Commit Graph

2295 Commits

Author SHA1 Message Date
Linus Torvalds
82339c4911 sanitize xattr and io_uring interactions with it,
add *xattrat() syscalls, sanitize struct filename handling in there.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull xattr updates from Al Viro:
 "Sanitize xattr and io_uring interactions with it, add *xattrat()
  syscalls, sanitize struct filename handling in there"

* tag 'pull-xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  xattr: remove redundant check on variable err
  fs/xattr: add *at family syscalls
  new helpers: file_removexattr(), filename_removexattr()
  new helpers: file_listxattr(), filename_listxattr()
  replace do_getxattr() with saner helpers.
  replace do_setxattr() with saner helpers.
  new helper: import_xattr_name()
  fs: rename struct xattr_ctx to kernel_xattr_ctx
  xattr: switch to CLASS(fd)
  io_[gs]etxattr_prep(): just use getname()
  io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE
  getname_maybe_null() - the third variant of pathname copy-in
  teach filename_lookup() to treat NULL filename as ""
2024-11-18 12:44:25 -08:00
Linus Torvalds
241c7ed4d4 vfs-6.13.untorn.writes
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Merge tag 'vfs-6.13.untorn.writes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs untorn write support from Christian Brauner:
 "An atomic write is a write issed with torn-write protection. This
  means for a power failure or any hardware failure all or none of the
  data from the write will be stored, never a mix of old and new data.

  This work is already supported for block devices. If a block device is
  opened with O_DIRECT and the block device supports atomic write, then
  FMODE_CAN_ATOMIC_WRITE is added to the file of the opened block
  device.

  This contains the work to expand atomic write support to filesystems,
  specifically ext4 and XFS. Currently, only support for writing exactly
  one filesystem block atomically is added.

  Since it's now possible to have filesystem block size > page size for
  XFS, it's possible to write 4K+ blocks atomically on x86"

* tag 'vfs-6.13.untorn.writes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: drop an obsolete comment in iomap_dio_bio_iter
  ext4: Do not fallback to buffered-io for DIO atomic write
  ext4: Support setting FMODE_CAN_ATOMIC_WRITE
  ext4: Check for atomic writes support in write iter
  ext4: Add statx support for atomic writes
  xfs: Support setting FMODE_CAN_ATOMIC_WRITE
  xfs: Validate atomic writes
  xfs: Support atomic write for statx
  fs: iomap: Atomic write support
  fs: Export generic_atomic_write_valid()
  block: Add bdev atomic write limits helpers
  fs/block: Check for IOCB_DIRECT in generic_atomic_write_valid()
  block/fs: Pass an iocb to generic_atomic_write_valid()
2024-11-18 11:30:09 -08:00
Linus Torvalds
7956186e75 vfs-6.13.tmpfs
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Merge tag 'vfs-6.13.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull tmpfs case folding updates from Christian Brauner:
 "This adds case-insensitive support for tmpfs.

  The work contained in here adds support for case-insensitive file
  names lookups in tmpfs. The main difference from other casefold
  filesystems is that tmpfs has no information on disk, just on RAM, so
  we can't use mkfs to create a case-insensitive tmpfs. For this
  implementation, there's a mount option for casefolding. The rest of
  the patchset follows a similar approach as ext4 and f2fs.

  The use case for this feature is similar to the use case for ext4, to
  better support compatibility layers (like Wine), particularly in
  combination with sandboxing/container tools (like Flatpak).

  Those containerization tools can share a subset of the host filesystem
  with an application. In the container, the root directory and any
  parent directories required for a shared directory are on tmpfs, with
  the shared directories bind-mounted into the container's view of the
  filesystem.

  If the host filesystem is using case-insensitive directories, then the
  application can do lookups inside those directories in a
  case-insensitive way, without this needing to be implemented in
  user-space. However, if the host is only sharing a subset of a
  case-insensitive directory with the application, then the parent
  directories of the mount point will be part of the container's root
  tmpfs. When the application tries to do case-insensitive lookups of
  those parent directories on a case-sensitive tmpfs, the lookup will
  fail"

* tag 'vfs-6.13.tmpfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  tmpfs: Initialize sysfs during tmpfs init
  tmpfs: Fix type for sysfs' casefold attribute
  libfs: Fix kernel-doc warning in generic_ci_validate_strict_name
  docs: tmpfs: Add casefold options
  tmpfs: Expose filesystem features via sysfs
  tmpfs: Add flag FS_CASEFOLD_FL support for tmpfs dirs
  tmpfs: Add casefold lookup support
  libfs: Export generic_ci_ dentry functions
  unicode: Recreate utf8_parse_version()
  unicode: Export latest available UTF-8 version number
  ext4: Use generic_ci_validate_strict_name helper
  libfs: Create the helper function generic_ci_validate_strict_name()
2024-11-18 11:05:26 -08:00
Linus Torvalds
4c797b11a8 vfs-6.13.file
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Merge tag 'vfs-6.13.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs file updates from Christian Brauner:
 "This contains changes the changes for files for this cycle:

   - Introduce a new reference counting mechanism for files.

     As atomic_inc_not_zero() is implemented with a try_cmpxchg() loop
     it has O(N^2) behaviour under contention with N concurrent
     operations and it is in a hot path in __fget_files_rcu().

     The rcuref infrastructures remedies this problem by using an
     unconditional increment relying on safe- and dead zones to make
     this work and requiring rcu protection for the data structure in
     question. This not just scales better it also introduces overflow
     protection.

     However, in contrast to generic rcuref, files require a memory
     barrier and thus cannot rely on *_relaxed() atomic operations and
     also require to be built on atomic_long_t as having massive amounts
     of reference isn't unheard of even if it is just an attack.

     This adds a file specific variant instead of making this a generic
     library.

     This has been tested by various people and it gives consistent
     improvement up to 3-5% on workloads with loads of threads.

   - Add a fastpath for find_next_zero_bit(). Skip 2-levels searching
     via find_next_zero_bit() when there is a free slot in the word that
     contains the next fd. This improves pts/blogbench-1.1.0 read by 8%
     and write by 4% on Intel ICX 160.

   - Conditionally clear full_fds_bits since it's very likely that a bit
     in full_fds_bits has been cleared during __clear_open_fds(). This
     improves pts/blogbench-1.1.0 read up to 13%, and write up to 5% on
     Intel ICX 160.

   - Get rid of all lookup_*_fdget_rcu() variants. They were used to
     lookup files without taking a reference count. That became invalid
     once files were switched to SLAB_TYPESAFE_BY_RCU and now we're
     always taking a reference count. Switch to an already existing
     helper and remove the legacy variants.

   - Remove pointless includes of <linux/fdtable.h>.

   - Avoid cmpxchg() in close_files() as nobody else has a reference to
     the files_struct at that point.

   - Move close_range() into fs/file.c and fold __close_range() into it.

   - Cleanup calling conventions of alloc_fdtable() and expand_files().

   - Merge __{set,clear}_close_on_exec() into one.

   - Make __set_open_fd() set cloexec as well instead of doing it in two
     separate steps"

* tag 'vfs-6.13.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  selftests: add file SLAB_TYPESAFE_BY_RCU recycling stressor
  fs: port files to file_ref
  fs: add file_ref
  expand_files(): simplify calling conventions
  make __set_open_fd() set cloexec state as well
  fs: protect backing files with rcu
  file.c: merge __{set,clear}_close_on_exec()
  alloc_fdtable(): change calling conventions.
  fs/file.c: add fast path in find_next_fd()
  fs/file.c: conditionally clear full_fds
  fs/file.c: remove sanity_check and add likely/unlikely in alloc_fd()
  move close_range(2) into fs/file.c, fold __close_range() into it
  close_files(): don't bother with xchg()
  remove pointless includes of <linux/fdtable.h>
  get rid of ...lookup...fdget_rcu() family
2024-11-18 10:30:29 -08:00
Linus Torvalds
70e7730c2a vfs-6.13.misc
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Merge tag 'vfs-6.13.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "Features:

   - Fixup and improve NLM and kNFSD file lock callbacks

     Last year both GFS2 and OCFS2 had some work done to make their
     locking more robust when exported over NFS. Unfortunately, part of
     that work caused both NLM (for NFS v3 exports) and kNFSD (for
     NFSv4.1+ exports) to no longer send lock notifications to clients

     This in itself is not a huge problem because most NFS clients will
     still poll the server in order to acquire a conflicted lock

     It's important for NLM and kNFSD that they do not block their
     kernel threads inside filesystem's file_lock implementations
     because that can produce deadlocks. We used to make sure of this by
     only trusting that posix_lock_file() can correctly handle blocking
     lock calls asynchronously, so the lock managers would only setup
     their file_lock requests for async callbacks if the filesystem did
     not define its own lock() file operation

     However, when GFS2 and OCFS2 grew the capability to correctly
     handle blocking lock requests asynchronously, they started
     signalling this behavior with EXPORT_OP_ASYNC_LOCK, and the check
     for also trusting posix_lock_file() was inadvertently dropped, so
     now most filesystems no longer produce lock notifications when
     exported over NFS

     Fix this by using an fop_flag which greatly simplifies the problem
     and grooms the way for future uses by both filesystems and lock
     managers alike

   - Add a sysctl to delete the dentry when a file is removed instead of
     making it a negative dentry

     Commit 681ce86235 ("vfs: Delete the associated dentry when
     deleting a file") introduced an unconditional deletion of the
     associated dentry when a file is removed. However, this led to
     performance regressions in specific benchmarks, such as
     ilebench.sum_operations/s, prompting a revert in commit
     4a4be1ad3a ("Revert "vfs: Delete the associated dentry when
     deleting a file""). This reintroduces the concept conditionally
     through a sysctl

   - Expand the statmount() system call:

       * Report the filesystem subtype in a new fs_subtype field to
         e.g., report fuse filesystem subtypes

       * Report the superblock source in a new sb_source field

       * Add a new way to return filesystem specific mount options in an
         option array that returns filesystem specific mount options
         separated by zero bytes and unescaped. This allows caller's to
         retrieve filesystem specific mount options and immediately pass
         them to e.g., fsconfig() without having to unescape or split
         them

       * Report security (LSM) specific mount options in a separate
         security option array. We don't lump them together with
         filesystem specific mount options as security mount options are
         generic and most users aren't interested in them

         The format is the same as for the filesystem specific mount
         option array

   - Support relative paths in fsconfig()'s FSCONFIG_SET_STRING command

   - Optimize acl_permission_check() to avoid costly {g,u}id ownership
     checks if possible

   - Use smp_mb__after_spinlock() to avoid full smp_mb() in evict()

   - Add synchronous wakeup support for ep_poll_callback.

     Currently, epoll only uses wake_up() to wake up task. But sometimes
     there are epoll users which want to use the synchronous wakeup flag
     to give a hint to the scheduler, e.g., the Android binder driver.
     So add a wake_up_sync() define, and use wake_up_sync() when sync is
     true in ep_poll_callback()

  Fixes:

   - Fix kernel documentation for inode_insert5() and iget5_locked()

   - Annotate racy epoll check on file->f_ep

   - Make F_DUPFD_QUERY associative

   - Avoid filename buffer overrun in initramfs

   - Don't let statmount() return empty strings

   - Add a cond_resched() to dump_user_range() to avoid hogging the CPU

   - Don't query the device logical blocksize multiple times for hfsplus

   - Make filemap_read() check that the offset is positive or zero

  Cleanups:

   - Various typo fixes

   - Cleanup wbc_attach_fdatawrite_inode()

   - Add __releases annotation to wbc_attach_and_unlock_inode()

   - Add hugetlbfs tracepoints

   - Fix various vfs kernel doc parameters

   - Remove obsolete TODO comment from io_cancel()

   - Convert wbc_account_cgroup_owner() to take a folio

   - Fix comments for BANDWITH_INTERVAL and wb_domain_writeout_add()

   - Reorder struct posix_acl to save 8 bytes

   - Annotate struct posix_acl with __counted_by()

   - Replace one-element array with flexible array member in freevxfs

   - Use idiomatic atomic64_inc_return() in alloc_mnt_ns()"

* tag 'vfs-6.13.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
  statmount: retrieve security mount options
  vfs: make evict() use smp_mb__after_spinlock instead of smp_mb
  statmount: add flag to retrieve unescaped options
  fs: add the ability for statmount() to report the sb_source
  writeback: wbc_attach_fdatawrite_inode out of line
  writeback: add a __releases annoation to wbc_attach_and_unlock_inode
  fs: add the ability for statmount() to report the fs_subtype
  fs: don't let statmount return empty strings
  fs:aio: Remove TODO comment suggesting hash or array usage in io_cancel()
  hfsplus: don't query the device logical block size multiple times
  freevxfs: Replace one-element array with flexible array member
  fs: optimize acl_permission_check()
  initramfs: avoid filename buffer overrun
  fs/writeback: convert wbc_account_cgroup_owner to take a folio
  acl: Annotate struct posix_acl with __counted_by()
  acl: Realign struct posix_acl to save 8 bytes
  epoll: Add synchronous wakeup support for ep_poll_callback
  coredump: add cond_resched() to dump_user_range
  mm/page-writeback.c: Fix comment of wb_domain_writeout_add()
  mm/page-writeback.c: Update comment for BANDWIDTH_INTERVAL
  ...
2024-11-18 09:35:30 -08:00
Linus Torvalds
6ac81fd55e vfs-6.13.mgtime
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Merge tag 'vfs-6.13.mgtime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs multigrain timestamps from Christian Brauner:
 "This is another try at implementing multigrain timestamps. This time
  with significant help from the timekeeping maintainers to reduce the
  performance impact.

  Thomas provided a base branch that contains the required timekeeping
  interfaces for the VFS. It serves as the base for the multi-grain
  timestamp work:

   - Multigrain timestamps allow the kernel to use fine-grained
     timestamps when an inode's attributes is being actively observed
     via ->getattr(). With this support, it's possible for a file to get
     a fine-grained timestamp, and another modified after it to get a
     coarse-grained stamp that is earlier than the fine-grained time. If
     this happens then the files can appear to have been modified in
     reverse order, which breaks VFS ordering guarantees.

     To prevent this, a floor value is maintained for multigrain
     timestamps. Whenever a fine-grained timestamp is handed out, record
     it, and when later coarse-grained stamps are handed out, ensure
     they are not earlier than that value. If the coarse-grained
     timestamp is earlier than the fine-grained floor, return the floor
     value instead.

     The timekeeper changes add a static singleton atomic64_t into
     timekeeper.c that is used to keep track of the latest fine-grained
     time ever handed out. This is tracked as a monotonic ktime_t value
     to ensure that it isn't affected by clock jumps. Because it is
     updated at different times than the rest of the timekeeper object,
     the floor value is managed independently of the timekeeper via a
     cmpxchg() operation, and sits on its own cacheline.

     Two new public timekeeper interfaces are added:

      (1) ktime_get_coarse_real_ts64_mg() fills a timespec64 with the
          later of the coarse-grained clock and the floor time

      (2) ktime_get_real_ts64_mg() gets the fine-grained clock value,
          and tries to swap it into the floor. A timespec64 is filled
          with the result.

   - The VFS has always used coarse-grained timestamps when updating the
     ctime and mtime after a change. This has the benefit of allowing
     filesystems to optimize away a lot metadata updates, down to around
     1 per jiffy, even when a file is under heavy writes.

     Unfortunately, this has always been an issue when we're exporting
     via NFSv3, which relies on timestamps to validate caches. A lot of
     changes can happen in a jiffy, so timestamps aren't sufficient to
     help the client decide when to invalidate the cache. Even with
     NFSv4, a lot of exported filesystems don't properly support a
     change attribute and are subject to the same problems with
     timestamp granularity. Other applications have similar issues with
     timestamps (e.g backup applications).

     If we were to always use fine-grained timestamps, that would
     improve the situation, but that becomes rather expensive, as the
     underlying filesystem would have to log a lot more metadata
     updates.

     This adds a way to only use fine-grained timestamps when they are
     being actively queried. Use the (unused) top bit in
     inode->i_ctime_nsec as a flag that indicates whether the current
     timestamps have been queried via stat() or the like. When it's set,
     we allow the kernel to use a fine-grained timestamp iff it's
     necessary to make the ctime show a different value.

     This solves the problem of being able to distinguish the timestamp
     between updates, but introduces a new problem: it's now possible
     for a file being changed to get a fine-grained timestamp. A file
     that is altered just a bit later can then get a coarse-grained one
     that appears older than the earlier fine-grained time. This
     violates timestamp ordering guarantees.

     This is where the earlier mentioned timkeeping interfaces help. A
     global monotonic atomic64_t value is kept that acts as a timestamp
     floor. When we go to stamp a file, we first get the latter of the
     current floor value and the current coarse-grained time. If the
     inode ctime hasn't been queried then we just attempt to stamp it
     with that value.

     If it has been queried, then first see whether the current coarse
     time is later than the existing ctime. If it is, then we accept
     that value. If it isn't, then we get a fine-grained time and try to
     swap that into the global floor. Whether that succeeds or fails, we
     take the resulting floor time, convert it to realtime and try to
     swap that into the ctime.

     We take the result of the ctime swap whether it succeeds or fails,
     since either is just as valid.

     Filesystems can opt into this by setting the FS_MGTIME fstype flag.
     Others should be unaffected (other than being subject to the same
     floor value as multigrain filesystems)"

* tag 'vfs-6.13.mgtime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: reduce pointer chasing in is_mgtime() test
  tmpfs: add support for multigrain timestamps
  btrfs: convert to multigrain timestamps
  ext4: switch to multigrain timestamps
  xfs: switch to multigrain timestamps
  Documentation: add a new file documenting multigrain timestamps
  fs: add percpu counters for significant multigrain timestamp events
  fs: tracepoints around multigrain timestamp events
  fs: handle delegated timestamps in setattr_copy_mgtime
  timekeeping: Add percpu counter for tracking floor swap events
  timekeeping: Add interfaces for handling timestamps with a floor value
  fs: have setattr_copy handle multigrain timestamps appropriately
  fs: add infrastructure for multigrain timestamps
2024-11-18 09:15:39 -08:00
Jeff Layton
9fed2c0f2f
fs: reduce pointer chasing in is_mgtime() test
The is_mgtime test checks whether the FS_MGTIME flag is set in the
fstype. To get there from the inode though, we have to dereference 3
pointers.

Add a new IOP_MGTIME flag, and have inode_init_always() set that flag
when the fstype flag is set. Then, make is_mgtime test for IOP_MGTIME
instead.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20241113-mgtime-v1-1-84e256980e11@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-14 10:45:53 +01:00
André Almeida
33b091c08e
libfs: Fix kernel-doc warning in generic_ci_validate_strict_name
Fix the indentation of the return values from
generic_ci_validate_strict_name() to properly render the comment and to
address a `make htmldocs` warning:

Documentation/filesystems/api-summary:14: include/linux/fs.h:3504:
WARNING: Bullet list ends without a blank line; unexpected unindent.

Fixes: 0e152beb5a ("libfs: Create the helper function generic_ci_validate_strict_name()")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/lkml/20241030162435.05425f60@canb.auug.org.au/
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241101164251.327884-2-andrealmeid@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-06 11:22:20 +01:00
Christian Brauner
90ee6ed776
fs: port files to file_ref
Port files to rely on file_ref reference to improve scaling and gain
overflow protection.

- We continue to WARN during get_file() in case a file that is already
  marked dead is revived as get_file() is only valid if the caller
  already holds a reference to the file. This hasn't changed just the
  check changes.

- The semantics for epoll and ttm's dmabuf usage have changed. Both
  epoll and ttm synchronize with __fput() to prevent the underlying file
  from beeing freed.

  (1) epoll

      Explaining epoll is straightforward using a simple diagram.
      Essentially, the mutex of the epoll instance needs to be taken in both
      __fput() and around epi_fget() preventing the file from being freed
      while it is polled or preventing the file from being resurrected.

          CPU1                                   CPU2
          fput(file)
          -> __fput(file)
             -> eventpoll_release(file)
                -> eventpoll_release_file(file)
                                                 mutex_lock(&ep->mtx)
                                                 epi_item_poll()
                                                 -> epi_fget()
                                                    -> file_ref_get(file)
                                                 mutex_unlock(&ep->mtx)
                   mutex_lock(&ep->mtx);
                   __ep_remove()
                   mutex_unlock(&ep->mtx);
             -> kmem_cache_free(file)

  (2) ttm dmabuf

      This explanation is a bit more involved. A regular dmabuf file stashed
      the dmabuf in file->private_data and the file in dmabuf->file:

          file->private_data = dmabuf;
          dmabuf->file = file;

      The generic release method of a dmabuf file handles file specific
      things:

          f_op->release::dma_buf_file_release()

      while the generic dentry release method of a dmabuf handles dmabuf
      freeing including driver specific things:

          dentry->d_release::dma_buf_release()

      During ttm dmabuf initialization in ttm_object_device_init() the ttm
      driver copies the provided struct dma_buf_ops into a private location:

          struct ttm_object_device {
                  spinlock_t object_lock;
                  struct dma_buf_ops ops;
                  void (*dmabuf_release)(struct dma_buf *dma_buf);
                  struct idr idr;
          };

          ttm_object_device_init(const struct dma_buf_ops *ops)
          {
                  // copy original dma_buf_ops in private location
                  tdev->ops = *ops;

                  // stash the release method of the original struct dma_buf_ops
                  tdev->dmabuf_release = tdev->ops.release;

                  // override the release method in the copy of the struct dma_buf_ops
                  // with ttm's own dmabuf release method
                  tdev->ops.release = ttm_prime_dmabuf_release;
          }

      When a new dmabuf is created the struct dma_buf_ops with the overriden
      release method set to ttm_prime_dmabuf_release is passed in exp_info.ops:

          DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
          exp_info.ops = &tdev->ops;
          exp_info.size = prime->size;
          exp_info.flags = flags;
          exp_info.priv = prime;

      The call to dma_buf_export() then sets

          mutex_lock_interruptible(&prime->mutex);
          dma_buf = dma_buf_export(&exp_info)
          {
                  dmabuf->ops = exp_info->ops;
          }
          mutex_unlock(&prime->mutex);

      which creates a new dmabuf file and then install a file descriptor to
      it in the callers file descriptor table:

          ret = dma_buf_fd(dma_buf, flags);

      When that dmabuf file is closed we now get:

          fput(file)
          -> __fput(file)
             -> f_op->release::dma_buf_file_release()
             -> dput()
                -> d_op->d_release::dma_buf_release()
                   -> dmabuf->ops->release::ttm_prime_dmabuf_release()
                      mutex_lock(&prime->mutex);
                      if (prime->dma_buf == dma_buf)
                            prime->dma_buf = NULL;
                      mutex_unlock(&prime->mutex);

      Where we can see that prime->dma_buf is set to NULL. So when we have
      the following diagram:

          CPU1                                                          CPU2
          fput(file)
          -> __fput(file)
             -> f_op->release::dma_buf_file_release()
             -> dput()
                -> d_op->d_release::dma_buf_release()
                   -> dmabuf->ops->release::ttm_prime_dmabuf_release()
                                                                        ttm_prime_handle_to_fd()
                                                                        mutex_lock_interruptible(&prime->mutex)
                                                                        dma_buf = prime->dma_buf
                                                                        dma_buf && get_dma_buf_unless_doomed(dma_buf)
                                                                        -> file_ref_get(dma_buf->file)
                                                                        mutex_unlock(&prime->mutex);

                      mutex_lock(&prime->mutex);
                      if (prime->dma_buf == dma_buf)
                            prime->dma_buf = NULL;
                      mutex_unlock(&prime->mutex);
             -> kmem_cache_free(file)

      The logic of the mechanism is the same as for epoll: sync with
      __fput() preventing the file from being freed. Here the
      synchronization happens through the ttm instance's prime->mutex.
      Basically, the lifetime of the dma_buf and the file are tighly
      coupled.

  Both (1) and (2) used to call atomic_inc_not_zero() to check whether
  the file has already been marked dead and then refuse to revive it.

  This is only safe because both (1) and (2) sync with __fput() and thus
  prevent kmem_cache_free() on the file being called and thus prevent
  the file from being immediately recycled due to SLAB_TYPESAFE_BY_RCU.

  Both (1) and (2) have been ported from atomic_inc_not_zero() to
  file_ref_get(). That means a file that is already in the process of
  being marked as FILE_REF_DEAD:

  file_ref_put()
  cnt = atomic_long_dec_return()
  -> __file_ref_put(cnt)
     if (cnt == FIlE_REF_NOREF)
             atomic_long_try_cmpxchg_release(cnt, FILE_REF_DEAD)

  can be revived again:

  CPU1                                                             CPU2
  file_ref_put()
  cnt = atomic_long_dec_return()
  -> __file_ref_put(cnt)
     if (cnt == FIlE_REF_NOREF)
                                                                   file_ref_get()
                                                                   // Brings reference back to FILE_REF_ONEREF
                                                                   atomic_long_add_negative()
             atomic_long_try_cmpxchg_release(cnt, FILE_REF_DEAD)

  This is fine and inherent to the file_ref_get()/file_ref_put()
  semantics. For both (1) and (2) this is safe because __fput() is
  prevented from making progress if file_ref_get() fails due to the
  aforementioned synchronization mechanisms.

  Two cases need to be considered that affect both (1) epoll and (2) ttm
  dmabuf:

   (i) fput()'s file_ref_put() and marks the file as FILE_REF_NOREF but
       before that fput() can mark the file as FILE_REF_DEAD someone
       manages to sneak in a file_ref_get() and brings the refcount back
       from FILE_REF_NOREF to FILE_REF_ONEREF. In that case the original
       fput() doesn't call __fput(). For epoll the poll will finish and
       for ttm dmabuf the file can be used again. For ttm dambuf this is
       actually an advantage because it avoids immediately allocating
       a new dmabuf object.

       CPU1                                                             CPU2
       file_ref_put()
       cnt = atomic_long_dec_return()
       -> __file_ref_put(cnt)
          if (cnt == FIlE_REF_NOREF)
                                                                        file_ref_get()
                                                                        // Brings reference back to FILE_REF_ONEREF
                                                                        atomic_long_add_negative()
                  atomic_long_try_cmpxchg_release(cnt, FILE_REF_DEAD)

  (ii) fput()'s file_ref_put() marks the file FILE_REF_NOREF and
       also suceeds in actually marking it FILE_REF_DEAD and then calls
       into __fput() to free the file.

       When either (1) or (2) call file_ref_get() they fail as
       atomic_long_add_negative() will return true.

       At the same time, both (1) and (2) all file_ref_get() under
       mutexes that __fput() must also acquire preventing
       kmem_cache_free() from freeing the file.

  So while this might be treated as a change in semantics for (1) and
  (2) it really isn't. It if should end up causing issues this can be
  fixed by adding a helper that does something like:

  long cnt = atomic_long_read(&ref->refcnt);
  do {
          if (cnt < 0)
                  return false;
  } while (!atomic_long_try_cmpxchg(&ref->refcnt, &cnt, cnt + 1));
  return true;

  which would block FILE_REF_NOREF to FILE_REF_ONEREF transitions.

- Jann correctly pointed out that kmem_cache_zalloc() cannot be used
  anymore once files have been ported to file_ref_t.

  The kmem_cache_zalloc() call will memset() the whole struct file to
  zero when it is reallocated. This will also set file->f_ref to zero
  which mens that a concurrent file_ref_get() can return true:

  CPU1                            CPU2
                                  __get_file_rcu()
                                    rcu_dereference_raw()
  close()
    [frees file]
  alloc_empty_file()
    kmem_cache_zalloc()
      [reallocates same file]
      memset(..., 0, ...)
                                    file_ref_get()
                                      [increments 0->1, returns true]
    init_file()
      file_ref_init(..., 1)
        [sets to 0]
                                    rcu_dereference_raw()
                                    fput()
                                      file_ref_put()
                                        [decrements 0->FILE_REF_NOREF, frees file]
    [UAF]

   causing a concurrent __get_file_rcu() call to acquire a reference to
   the file that is about to be reallocated and immediately freeing it
   on realizing that it has been recycled. This causes a UAF for the
   task that reallocated/recycled the file.

   This is prevented by switching from kmem_cache_zalloc() to
   kmem_cache_alloc() and initializing the fields manually. With
   file->f_ref initialized last.

   Note that a memset() also isn't guaranteed to atomically update an
   unsigned long so it's theoretically possible to see torn and
   therefore bogus counter values.

Link: https://lore.kernel.org/r/20241007-brauner-file-rcuref-v2-3-387e24dc9163@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-30 09:57:43 +01:00
André Almeida
458532c8df
libfs: Export generic_ci_ dentry functions
Export generic_ci_ dentry functions so they can be used by
case-insensitive filesystems that need something more custom than the
default one set by `struct generic_ci_dentry_ops`.

Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-5-f443d5814194@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-28 13:36:54 +01:00
André Almeida
0e152beb5a
libfs: Create the helper function generic_ci_validate_strict_name()
Create a helper function for filesystems do the checks required for
casefold directories and strict encoding.

Suggested-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-1-f443d5814194@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-28 13:36:53 +01:00
Al Viro
e896474fe4 getname_maybe_null() - the third variant of pathname copy-in
Semantics used by statx(2) (and later *xattrat(2)): without AT_EMPTY_PATH
it's standard getname() (i.e. ERR_PTR(-ENOENT) on empty string,
ERR_PTR(-EFAULT) on NULL), with AT_EMPTY_PATH both empty string and
NULL are accepted.

Calling conventions: getname_maybe_null(user_pointer, flags) returns
	* pointer to struct filename when non-empty string had been
successfully read
	* ERR_PTR(...) on error
	* NULL if an empty string or NULL pointer had been given
with AT_EMPTY_PATH in the flags argument.

It tries to avoid allocation in the last case; it's not always
able to do so, in which case the temporary struct filename instance
is freed and NULL returned anyway.

Fast path is inlined.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-10-19 20:33:34 -04:00
John Garry
c3be7ebbbc fs/block: Check for IOCB_DIRECT in generic_atomic_write_valid()
Currently FMODE_CAN_ATOMIC_WRITE is set if the bdev can atomic write and
the file is open for direct IO. This does not work if the file is not
opened for direct IO, yet fcntl(O_DIRECT) is used on the fd later.

Change to check for direct IO on a per-IO basis in
generic_atomic_write_valid(). Since we want to report -EOPNOTSUPP for
non-direct IO for an atomic write, change to return an error code.

Relocate the block fops atomic write checks to the common write path, as to
catch non-direct IO.

Fixes: c34fc6f26a ("fs: Initial atomic write support")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241019125113.369994-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-19 16:48:22 -06:00
John Garry
9a8dbdadae block/fs: Pass an iocb to generic_atomic_write_valid()
Darrick and Hannes both thought it better that generic_atomic_write_valid()
should be passed a struct iocb, and not just the member of that struct
which is referenced; see [0] and [1].

I think that makes a more generic and clean API, so make that change.

[0] https://lore.kernel.org/linux-block/680ce641-729b-4150-b875-531a98657682@suse.de/
[1] https://lore.kernel.org/linux-xfs/20240620212401.GA3058325@frogsfrogsfrogs/

Fixes: c34fc6f26a ("fs: Initial atomic write support")
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Suggested-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241019125113.369994-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-19 16:48:21 -06:00
Christian Brauner
b40508ca5d
Merge patch series "timekeeping/fs: multigrain timestamp redux"
Jeff Layton <jlayton@kernel.org> says:

The VFS has always used coarse-grained timestamps when updating the
ctime and mtime after a change. This has the benefit of allowing
filesystems to optimize away a lot metadata updates, down to around 1
per jiffy, even when a file is under heavy writes.

Unfortunately, this has always been an issue when we're exporting via
NFSv3, which relies on timestamps to validate caches. A lot of changes
can happen in a jiffy, so timestamps aren't sufficient to help the
client decide when to invalidate the cache. Even with NFSv4, a lot of
exported filesystems don't properly support a change attribute and are
subject to the same problems with timestamp granularity. Other
applications have similar issues with timestamps (e.g backup
applications).

If we were to always use fine-grained timestamps, that would improve the
situation, but that becomes rather expensive, as the underlying
filesystem would have to log a lot more metadata updates.

What we need is a way to only use fine-grained timestamps when they are
being actively queried. Use the (unused) top bit in inode->i_ctime_nsec
as a flag that indicates whether the current timestamps have been
queried via stat() or the like. When it's set, we allow the kernel to
use a fine-grained timestamp iff it's necessary to make the ctime show
a different value.

This solves the problem of being able to distinguish the timestamp
between updates, but introduces a new problem: it's now possible for a
file being changed to get a fine-grained timestamp. A file that is
altered just a bit later can then get a coarse-grained one that appears
older than the earlier fine-grained time. This violates timestamp
ordering guarantees.

To remedy this, keep a global monotonic atomic64_t value that acts as a
timestamp floor.  When we go to stamp a file, we first get the latter of
the current floor value and the current coarse-grained time. If the
inode ctime hasn't been queried then we just attempt to stamp it with
that value.

If it has been queried, then first see whether the current coarse time
is later than the existing ctime. If it is, then we accept that value.
If it isn't, then we get a fine-grained time and try to swap that into
the global floor. Whether that succeeds or fails, we take the resulting
floor time, convert it to realtime and try to swap that into the ctime.

We take the result of the ctime swap whether it succeeds or fails, since
either is just as valid.

Filesystems can opt into this by setting the FS_MGTIME fstype flag.
Others should be unaffected (other than being subject to the same floor
value as multigrain filesystems).

* patches from https://lore.kernel.org/r/20241002-mgtime-v10-0-d1c4717f5284@kernel.org:
  tmpfs: add support for multigrain timestamps
  btrfs: convert to multigrain timestamps
  ext4: switch to multigrain timestamps
  xfs: switch to multigrain timestamps
  Documentation: add a new file documenting multigrain timestamps
  fs: add percpu counters for significant multigrain timestamp events
  fs: tracepoints around multigrain timestamp events
  fs: handle delegated timestamps in setattr_copy_mgtime
  fs: have setattr_copy handle multigrain timestamps appropriately
  fs: add infrastructure for multigrain timestamps

Link: https://lore.kernel.org/r/20241002-mgtime-v10-0-d1c4717f5284@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-10 10:20:57 +02:00
Jeff Layton
7f2c86cba3
fs: handle delegated timestamps in setattr_copy_mgtime
An update to the inode ctime typically requires the latest clock
value possible. The exception to this rule is when there is a nfsd write
delegation and the server is proxying timestamps from the client.

When nfsd gets a CB_GETATTR response, update the timestamp value in the
inode to the values that the client is tracking. The client doesn't send
a ctime value (since that's always determined by the exported
filesystem), but it can send a mtime value. In the case where it does,
update the ctime to a value commensurate with that instead of the
current time.

If ATTR_DELEG is set, then use ia_ctime value instead of setting the
timestamp to the current time.

With the addition of delegated timestamps, the server may receive a
request to update only the atime, which doesn't involve a ctime update.
Trust the ATTR_CTIME flag in the update and only update the ctime when
it's set.

Tested-by: Randy Dunlap <rdunlap@infradead.org> # documentation bits
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20241002-mgtime-v10-5-d1c4717f5284@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-10 10:20:51 +02:00
Michal Hocko
9897713fe1 bcachefs: do not use PF_MEMALLOC_NORECLAIM
Patch series "remove PF_MEMALLOC_NORECLAIM" v3.


This patch (of 2):

bch2_new_inode relies on PF_MEMALLOC_NORECLAIM to try to allocate a new
inode to achieve GFP_NOWAIT semantic while holding locks. If this
allocation fails it will drop locks and use GFP_NOFS allocation context.

We would like to drop PF_MEMALLOC_NORECLAIM because it is really
dangerous to use if the caller doesn't control the full call chain with
this flag set. E.g. if any of the function down the chain needed
GFP_NOFAIL request the PF_MEMALLOC_NORECLAIM would override this and
cause unexpected failure.

While this is not the case in this particular case using the scoped gfp
semantic is not really needed bacause we can easily pus the allocation
context down the chain without too much clutter.

[akpm@linux-foundation.org: fix kerneldoc warnings]
Link: https://lkml.kernel.org/r/20240926172940.167084-1-mhocko@kernel.org
Link: https://lkml.kernel.org/r/20240926172940.167084-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz> # For vfs changes
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-09 12:47:18 -07:00
Jeff Layton
4e40eff0b5
fs: add infrastructure for multigrain timestamps
The VFS has always used coarse-grained timestamps when updating the
ctime and mtime after a change. This has the benefit of allowing
filesystems to optimize away a lot metadata updates, down to around 1
per jiffy, even when a file is under heavy writes.

Unfortunately, this has always been an issue when we're exporting via
NFSv3, which relies on timestamps to validate caches. A lot of changes
can happen in a jiffy, so timestamps aren't sufficient to help the
client decide when to invalidate the cache. Even with NFSv4, a lot of
exported filesystems don't properly support a change attribute and are
subject to the same problems with timestamp granularity. Other
applications have similar issues with timestamps (e.g backup
applications).

If fine-grained timestamps were always used, that would improve the
situation, but that becomes rather expensive, as the underlying
filesystem would have to log a lot more metadata updates.

What is needed is a way to only use fine-grained timestamps when they
are being actively queried. Use the (unused) top bit in
inode->i_ctime_nsec as a flag that indicates whether the current
timestamps have been queried via stat() or the like. When it's set,
allow the update to use a fine-grained timestamp iff it's necessary to
make the ctime show a different value.

If it has been queried, then first see whether the current coarse time
is later than the existing ctime. If it is, accept that value.  If it
isn't, then get a fine-grained timestamp and attempt to stamp the inode
ctime with that value. If that races with another concurrent stamp, then
abandon the update and take the new value without retrying.

Filesystems can opt into this by setting the FS_MGTIME fstype flag.
Others should be unaffected (other than being subject to the same floor
value as multigrain filesystems).

Tested-by: Randy Dunlap <rdunlap@infradead.org> # documentation bits
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20241002-mgtime-v10-3-d1c4717f5284@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-07 12:48:56 +02:00
Christian Brauner
09ee2a670d
Merge patch series "Fixup NLM and kNFSD file lock callbacks"
Benjamin Coddington <bcodding@redhat.com> says:

Last year both GFS2 and OCFS2 had some work done to make their locking more
robust when exported over NFS.  Unfortunately, part of that work caused both
NLM (for NFS v3 exports) and kNFSD (for NFSv4.1+ exports) to no longer send
lock notifications to clients.

This in itself is not a huge problem because most NFS clients will still
poll the server in order to acquire a conflicted lock, but now that I've
noticed it I can't help but try to fix it because there are big advantages
for setups that might depend on timely lock notifications, and we've
supported that as a feature for a long time.

Its important for NLM and kNFSD that they do not block their kernel threads
inside filesystem's file_lock implementations because that can produce
deadlocks.  We used to make sure of this by only trusting that
posix_lock_file() can correctly handle blocking lock calls asynchronously,
so the lock managers would only setup their file_lock requests for async
callbacks if the filesystem did not define its own lock() file operation.

However, when GFS2 and OCFS2 grew the capability to correctly
handle blocking lock requests asynchronously, they started signalling this
behavior with EXPORT_OP_ASYNC_LOCK, and the check for also trusting
posix_lock_file() was inadvertently dropped, so now most filesystems no
longer produce lock notifications when exported over NFS.

I tried to fix this by simply including the old check for lock(), but the
resulting include mess and layering violations was more than I could accept.
There's a much cleaner way presented here using an fop_flag, which while
potentially flag-greedy, greatly simplifies the problem and grooms the
way for future uses by both filesystems and lock managers alike.

* patches from https://lore.kernel.org/r/cover.1726083391.git.bcodding@redhat.com:
  exportfs: Remove EXPORT_OP_ASYNC_LOCK
  NLM/NFSD: Fix lock notifications for async-capable filesystems
  gfs2/ocfs2: set FOP_ASYNC_LOCK
  fs: Introduce FOP_ASYNC_LOCK
  NFS: trace: show TIMEDOUT instead of 0x6e
  nfsd: use system_unbound_wq for nfsd_file_gc_worker()
  nfsd: count nfsd_file allocations
  nfsd: fix refcount leak when file is unhashed after being found
  nfsd: remove unneeded EEXIST error check in nfsd_do_file_acquire
  nfsd: add list_head nf_gc to struct nfsd_file

Link: https://lore.kernel.org/r/cover.1726083391.git.bcodding@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-02 07:52:07 +02:00
Al Viro
cb787f4ac0 [tree-wide] finally take no_llseek out
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-27 08:18:43 -07:00
Linus Torvalds
f7fccaa772 fuse update for 6.12
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Merge tag 'fuse-update-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Add support for idmapped fuse mounts (Alexander Mikhalitsyn)

 - Add optimization when checking for writeback (yangyun)

 - Add tracepoints (Josef Bacik)

 - Clean up writeback code (Joanne Koong)

 - Clean up request queuing (me)

 - Misc fixes

* tag 'fuse-update-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (32 commits)
  fuse: use exclusive lock when FUSE_I_CACHE_IO_MODE is set
  fuse: clear FR_PENDING if abort is detected when sending request
  fs/fuse: convert to use invalid_mnt_idmap
  fs/mnt_idmapping: introduce an invalid_mnt_idmap
  fs/fuse: introduce and use fuse_simple_idmap_request() helper
  fs/fuse: fix null-ptr-deref when checking SB_I_NOIDMAP flag
  fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN
  virtio_fs: allow idmapped mounts
  fuse: allow idmapped mounts
  fuse: warn if fuse_access is called when idmapped mounts are allowed
  fuse: handle idmappings properly in ->write_iter()
  fuse: support idmapped ->rename op
  fuse: support idmapped ->set_acl
  fuse: drop idmap argument from __fuse_get_acl
  fuse: support idmapped ->setattr op
  fuse: support idmapped ->permission inode op
  fuse: support idmapped getattr inode op
  fuse: support idmap for mkdir/mknod/symlink/create/tmpfile
  fuse: support idmapped FUSE_EXT_GROUPS
  fuse: add an idmap argument to fuse_simple_request
  ...
2024-09-24 15:29:42 -07:00
Linus Torvalds
b3f391fddf bcachefs changes for 6.12-rc1
rcu_pending, btree key cache rework: this solves lock contenting in the
 key cache, eliminating the biggest source of the srcu lock hold time
 warnings, and drastically improving performance on some metadata heavy
 workloads - on multithreaded creates we're now 3-4x faster than xfs.
 
 We're now using an rhashtable instead of the system inode hash table;
 this is another significant performance improvement on multithreaded
 metadata workloads, eliminating more lock contention.
 
 for_each_btree_key_in_subvolume_upto(): new helper for iterating over
 keys within a specific subvolume, eliminating a lot of open coded
 "subvolume_get_snapshot()" and also fixing another source of srcu lock
 time warnings, by running each loop iteration in its own transaction (as
 the existing for_each_btree_key() does).
 
 More work on btree_trans locking asserts; we now assert that we don't
 hold btree node locks when trans->locked is false, which is important
 because we don't use lockdep for tracking individual btree node locks.
 
 Some cleanups and improvements in the bset.c btree node lookup code,
 from Alan.
 
 Rework of btree node pinning, which we use in backpointers fsck. The old
 hacky implementation, where the shrinker just skipped over nodes in the
 pinned range, was causing OOMs; instead we now use another shrinker with
 a much higher seeks number for pinned nodes.
 
 Rebalance now uses BCH_WRITE_ONLY_SPECIFIED_DEVS; this fixes an issue
 where rebalance would sometimes fall back to allocating from the full
 filesystem, which is not what we want when it's trying to move data to a
 specific target.
 
 Use __GFP_ACCOUNT, GFP_RECLAIMABLE for btree node, key cache
 allocations.
 
 Idmap mounts are now supported - Hongbo.
 
 Rename whiteouts are now supported - Hongbo.
 
 Erasure coding can now handle devices being marked as failed, or
 forcibly removed. We still need the evacuate path for erasure coding,
 but it's getting very close to ready for people to start using.
 
 Status, and when will we be taking off experimental:
 ----------------------------------------------------
 
 Going by critical, user facing bugs getting found and fixed, we're
 nearly there. There are a couple key items that need to be finished
 before we can take off the experimental label:
 
 - The end-user experience is still pretty painful when the root
   filesystem needs a fsck; we need some form of limited self healing so
   that necessary repair gets run automatically. Errors (by type) are
   recorded in the superblock, so what we need to do next is convert
   remaining inconsistent() errors to fsck() errors (so that all runtime
   inconsistencies are logged in the superblock), and we need to go
   through the list of fsck errors and classify them by which fsck passes
   are needed to repair them.
 
 - We need comprehensive torture testing for all our repair paths, to
   shake out remaining bugs there. Thomas has been working on the tooling
   for this, so this is coming soonish.
 
 Slightly less critical items:
 
 - We need to improve the end-user experience for degraded mounts: right
   now, a degraded root filesystem means dropping to an initramfs shell
   or somehow inputting mount options manually (we don't want to allow
   degraded mounts without some form of user input, except on unattended
   servers) - we need the mount helper to prompt the user to allow
   mounting degraded, and make sure this works with systemd.
 
 - Scalabiity: we have users running 100TB+ filesystems, and that's
   effectively the limit right now due to fsck times. We have some
   reworks in the pipeline to address this, we're aiming to make petabyte
   sized filesystems practical.
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Merge tag 'bcachefs-2024-09-21' of git://evilpiepirate.org/bcachefs

Pull bcachefs updates from Kent Overstreet:

 - rcu_pending, btree key cache rework: this solves lock contenting in
   the key cache, eliminating the biggest source of the srcu lock hold
   time warnings, and drastically improving performance on some metadata
   heavy workloads - on multithreaded creates we're now 3-4x faster than
   xfs.

 - We're now using an rhashtable instead of the system inode hash table;
   this is another significant performance improvement on multithreaded
   metadata workloads, eliminating more lock contention.

 - for_each_btree_key_in_subvolume_upto(): new helper for iterating over
   keys within a specific subvolume, eliminating a lot of open coded
   "subvolume_get_snapshot()" and also fixing another source of srcu
   lock time warnings, by running each loop iteration in its own
   transaction (as the existing for_each_btree_key() does).

 - More work on btree_trans locking asserts; we now assert that we don't
   hold btree node locks when trans->locked is false, which is important
   because we don't use lockdep for tracking individual btree node
   locks.

 - Some cleanups and improvements in the bset.c btree node lookup code,
   from Alan.

 - Rework of btree node pinning, which we use in backpointers fsck. The
   old hacky implementation, where the shrinker just skipped over nodes
   in the pinned range, was causing OOMs; instead we now use another
   shrinker with a much higher seeks number for pinned nodes.

 - Rebalance now uses BCH_WRITE_ONLY_SPECIFIED_DEVS; this fixes an issue
   where rebalance would sometimes fall back to allocating from the full
   filesystem, which is not what we want when it's trying to move data
   to a specific target.

 - Use __GFP_ACCOUNT, GFP_RECLAIMABLE for btree node, key cache
   allocations.

 - Idmap mounts are now supported (Hongbo Li)

 - Rename whiteouts are now supported (Hongbo Li)

 - Erasure coding can now handle devices being marked as failed, or
   forcibly removed. We still need the evacuate path for erasure coding,
   but it's getting very close to ready for people to start using.

* tag 'bcachefs-2024-09-21' of git://evilpiepirate.org/bcachefs: (99 commits)
  bcachefs: return err ptr instead of null in read sb clean
  bcachefs: Remove duplicated include in backpointers.c
  bcachefs: Don't drop devices with stripe pointers
  bcachefs: bch2_ec_stripe_head_get() now checks for change in rw devices
  bcachefs: bch_fs.rw_devs_change_count
  bcachefs: bch2_dev_remove_stripes()
  bcachefs: bch2_trigger_ptr() calculates sectors even when no device
  bcachefs: improve error messages in bch2_ec_read_extent()
  bcachefs: improve error message on too few devices for ec
  bcachefs: improve bch2_new_stripe_to_text()
  bcachefs: ec_stripe_head.nr_created
  bcachefs: bch_stripe.disk_label
  bcachefs: stripe_to_mem()
  bcachefs: EIO errcode cleanup
  bcachefs: Rework btree node pinning
  bcachefs: split up btree cache counters for live, freeable
  bcachefs: btree cache counters should be size_t
  bcachefs: Don't count "skipped access bit" as touched in btree cache scan
  bcachefs: Failed devices no longer require mounting in degraded mode
  bcachefs: bch2_dev_rcu_noerror()
  ...
2024-09-23 10:05:41 -07:00
Linus Torvalds
617a814f14 ALong with the usual shower of singleton patches, notable patch series in
this pull request are:
 
 "Align kvrealloc() with krealloc()" from Danilo Krummrich.  Adds
 consistency to the APIs and behaviour of these two core allocation
 functions.  This also simplifies/enables Rustification.
 
 "Some cleanups for shmem" from Baolin Wang.  No functional changes - mode
 code reuse, better function naming, logic simplifications.
 
 "mm: some small page fault cleanups" from Josef Bacik.  No functional
 changes - code cleanups only.
 
 "Various memory tiering fixes" from Zi Yan.  A small fix and a little
 cleanup.
 
 "mm/swap: remove boilerplate" from Yu Zhao.  Code cleanups and
 simplifications and .text shrinkage.
 
 "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt.  This
 is a feature, it adds new feilds to /proc/vmstat such as
 
     $ grep kstack /proc/vmstat
     kstack_1k 3
     kstack_2k 188
     kstack_4k 11391
     kstack_8k 243
     kstack_16k 0
 
 which tells us that 11391 processes used 4k of stack while none at all
 used 16k.  Useful for some system tuning things, but partivularly useful
 for "the dynamic kernel stack project".
 
 "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
 Teaches kmemleak to detect leaksage of percpu memory.
 
 "mm: memcg: page counters optimizations" from Roman Gushchin.  "3
 independent small optimizations of page counters".
 
 "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
 Hildenbrand.  Improves PTE/PMD splitlock detection, makes powerpc/8xx work
 correctly by design rather than by accident.
 
 "mm: remove arch_make_page_accessible()" from David Hildenbrand.  Some
 folio conversions which make arch_make_page_accessible() unneeded.
 
 "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
 Cleans up and fixes our handling of the resetting of the cgroup/process
 peak-memory-use detector.
 
 "Make core VMA operations internal and testable" from Lorenzo Stoakes.
 Rationalizaion and encapsulation of the VMA manipulation APIs.  With a
 view to better enable testing of the VMA functions, even from a
 userspace-only harness.
 
 "mm: zswap: fixes for global shrinker" from Takero Funaki.  Fix issues in
 the zswap global shrinker, resulting in improved performance.
 
 "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao.  Fill in
 some missing info in /proc/zoneinfo.
 
 "mm: replace follow_page() by folio_walk" from David Hildenbrand.  Code
 cleanups and rationalizations (conversion to folio_walk()) resulting in
 the removal of follow_page().
 
 "improving dynamic zswap shrinker protection scheme" from Nhat Pham.  Some
 tuning to improve zswap's dynamic shrinker.  Significant reductions in
 swapin and improvements in performance are shown.
 
 "mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
 Improvements to the new unaccepted memory feature,
 
 "mm/mprotect: Fix dax puds" from Peter Xu.  Implements mprotect on DAX
 PUDs.  This was missing, although nobody seems to have notied yet.
 
 "Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
 Cleanups and modest performance improvements for the maple tree library
 code.
 
 "memcg: further decouple v1 code from v2" from Shakeel Butt.  Move more
 cgroup v1 remnants away from the v2 memcg code.
 
 "memcg: initiate deprecation of v1 features" from Shakeel Butt.  Adds
 various warnings telling users that memcg v1 features are deprecated.
 
 "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
 Greatly improves the success rate of the mTHP swap allocation.
 
 "mm: introduce numa_memblks" from Mike Rapoport.  Moves various disparate
 per-arch implementations of numa_memblk code into generic code.
 
 "mm: batch free swaps for zap_pte_range()" from Barry Song.  Greatly
 improves the performance of munmap() of swap-filled ptes.
 
 "support large folio swap-out and swap-in for shmem" from Baolin Wang.
 With this series we no longer split shmem large folios into simgle-page
 folios when swapping out shmem.
 
 "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao.  Nice performance
 improvements and code reductions for gigantic folios.
 
 "support shmem mTHP collapse" from Baolin Wang.  Adds support for
 khugepaged's collapsing of shmem mTHP folios.
 
 "mm: Optimize mseal checks" from Pedro Falcato.  Fixes an mprotect()
 performance regression due to the addition of mseal().
 
 "Increase the number of bits available in page_type" from Matthew Wilcox.
 Increases the number of bits available in page_type!
 
 "Simplify the page flags a little" from Matthew Wilcox.  Many legacy page
 flags are now folio flags, so the page-based flags and their
 accessors/mutators can be removed.
 
 "mm: store zero pages to be swapped out in a bitmap" from Usama Arif.  An
 optimization which permits us to avoid writing/reading zero-filled zswap
 pages to backing store.
 
 "Avoid MAP_FIXED gap exposure" from Liam Howlett.  Fixes a race window
 which occurs when a MAP_FIXED operqtion is occurring during an unrelated
 vma tree walk.
 
 "mm: remove vma_merge()" from Lorenzo Stoakes.  Major rotorooting of the
 vma_merge() functionality, making ot cleaner, more testable and better
 tested.
 
 "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.  Minor
 fixups of DAMON selftests and kunit tests.
 
 "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.  Code
 cleanups and folio conversions.
 
 "Shmem mTHP controls and stats improvements" from Ryan Roberts.  Cleanups
 for shmem controls and stats.
 
 "mm: count the number of anonymous THPs per size" from Barry Song.  Expose
 additional anon THP stats to userspace for improved tuning.
 
 "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
 conversions and removal of now-unused page-based APIs.
 
 "replace per-quota region priorities histogram buffer with per-context
 one" from SeongJae Park.  DAMON histogram rationalization.
 
 "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
 Park.  DAMON documentation updates.
 
 "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
 related doc and warn" from Jason Wang: fixes usage of page allocator
 __GFP_NOFAIL and GFP_ATOMIC flags.
 
 "mm: split underused THPs" from Yu Zhao.  Improve THP=always policy - this
 was overprovisioning THPs in sparsely accessed memory areas.
 
 "zram: introduce custom comp backends API" frm Sergey Senozhatsky.  Add
 support for zram run-time compression algorithm tuning.
 
 "mm: Care about shadow stack guard gap when getting an unmapped area" from
 Mark Brown.  Fix up the various arch_get_unmapped_area() implementations
 to better respect guard areas.
 
 "Improve mem_cgroup_iter()" from Kinsey Ho.  Improve the reliability of
 mem_cgroup_iter() and various code cleanups.
 
 "mm: Support huge pfnmaps" from Peter Xu.  Extends the usage of huge
 pfnmap support.
 
 "resource: Fix region_intersects() vs add_memory_driver_managed()" from
 Huang Ying.  Fix a bug in region_intersects() for systems with CXL memory.
 
 "mm: hwpoison: two more poison recovery" from Kefeng Wang.  Teaches a
 couple more code paths to correctly recover from the encountering of
 poisoned memry.
 
 "mm: enable large folios swap-in support" from Barry Song.  Support the
 swapin of mTHP memory into appropriately-sized folios, rather than into
 single-page folios.
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Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Along with the usual shower of singleton patches, notable patch series
  in this pull request are:

   - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
     consistency to the APIs and behaviour of these two core allocation
     functions. This also simplifies/enables Rustification.

   - "Some cleanups for shmem" from Baolin Wang. No functional changes -
     mode code reuse, better function naming, logic simplifications.

   - "mm: some small page fault cleanups" from Josef Bacik. No
     functional changes - code cleanups only.

   - "Various memory tiering fixes" from Zi Yan. A small fix and a
     little cleanup.

   - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
     simplifications and .text shrinkage.

   - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
     Butt. This is a feature, it adds new feilds to /proc/vmstat such as

       $ grep kstack /proc/vmstat
       kstack_1k 3
       kstack_2k 188
       kstack_4k 11391
       kstack_8k 243
       kstack_16k 0

     which tells us that 11391 processes used 4k of stack while none at
     all used 16k. Useful for some system tuning things, but
     partivularly useful for "the dynamic kernel stack project".

   - "kmemleak: support for percpu memory leak detect" from Pavel
     Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.

   - "mm: memcg: page counters optimizations" from Roman Gushchin. "3
     independent small optimizations of page counters".

   - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
     David Hildenbrand. Improves PTE/PMD splitlock detection, makes
     powerpc/8xx work correctly by design rather than by accident.

   - "mm: remove arch_make_page_accessible()" from David Hildenbrand.
     Some folio conversions which make arch_make_page_accessible()
     unneeded.

   - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
     Finkel. Cleans up and fixes our handling of the resetting of the
     cgroup/process peak-memory-use detector.

   - "Make core VMA operations internal and testable" from Lorenzo
     Stoakes. Rationalizaion and encapsulation of the VMA manipulation
     APIs. With a view to better enable testing of the VMA functions,
     even from a userspace-only harness.

   - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
     issues in the zswap global shrinker, resulting in improved
     performance.

   - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
     in some missing info in /proc/zoneinfo.

   - "mm: replace follow_page() by folio_walk" from David Hildenbrand.
     Code cleanups and rationalizations (conversion to folio_walk())
     resulting in the removal of follow_page().

   - "improving dynamic zswap shrinker protection scheme" from Nhat
     Pham. Some tuning to improve zswap's dynamic shrinker. Significant
     reductions in swapin and improvements in performance are shown.

   - "mm: Fix several issues with unaccepted memory" from Kirill
     Shutemov. Improvements to the new unaccepted memory feature,

   - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
     DAX PUDs. This was missing, although nobody seems to have notied
     yet.

   - "Introduce a store type enum for the Maple tree" from Sidhartha
     Kumar. Cleanups and modest performance improvements for the maple
     tree library code.

   - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
     more cgroup v1 remnants away from the v2 memcg code.

   - "memcg: initiate deprecation of v1 features" from Shakeel Butt.
     Adds various warnings telling users that memcg v1 features are
     deprecated.

   - "mm: swap: mTHP swap allocator base on swap cluster order" from
     Chris Li. Greatly improves the success rate of the mTHP swap
     allocation.

   - "mm: introduce numa_memblks" from Mike Rapoport. Moves various
     disparate per-arch implementations of numa_memblk code into generic
     code.

   - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
     improves the performance of munmap() of swap-filled ptes.

   - "support large folio swap-out and swap-in for shmem" from Baolin
     Wang. With this series we no longer split shmem large folios into
     simgle-page folios when swapping out shmem.

   - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
     performance improvements and code reductions for gigantic folios.

   - "support shmem mTHP collapse" from Baolin Wang. Adds support for
     khugepaged's collapsing of shmem mTHP folios.

   - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
     performance regression due to the addition of mseal().

   - "Increase the number of bits available in page_type" from Matthew
     Wilcox. Increases the number of bits available in page_type!

   - "Simplify the page flags a little" from Matthew Wilcox. Many legacy
     page flags are now folio flags, so the page-based flags and their
     accessors/mutators can be removed.

   - "mm: store zero pages to be swapped out in a bitmap" from Usama
     Arif. An optimization which permits us to avoid writing/reading
     zero-filled zswap pages to backing store.

   - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
     window which occurs when a MAP_FIXED operqtion is occurring during
     an unrelated vma tree walk.

   - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
     the vma_merge() functionality, making ot cleaner, more testable and
     better tested.

   - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
     Minor fixups of DAMON selftests and kunit tests.

   - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
     Code cleanups and folio conversions.

   - "Shmem mTHP controls and stats improvements" from Ryan Roberts.
     Cleanups for shmem controls and stats.

   - "mm: count the number of anonymous THPs per size" from Barry Song.
     Expose additional anon THP stats to userspace for improved tuning.

   - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
     folio conversions and removal of now-unused page-based APIs.

   - "replace per-quota region priorities histogram buffer with
     per-context one" from SeongJae Park. DAMON histogram
     rationalization.

   - "Docs/damon: update GitHub repo URLs and maintainer-profile" from
     SeongJae Park. DAMON documentation updates.

   - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
     improve related doc and warn" from Jason Wang: fixes usage of page
     allocator __GFP_NOFAIL and GFP_ATOMIC flags.

   - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
     This was overprovisioning THPs in sparsely accessed memory areas.

   - "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
     Add support for zram run-time compression algorithm tuning.

   - "mm: Care about shadow stack guard gap when getting an unmapped
     area" from Mark Brown. Fix up the various arch_get_unmapped_area()
     implementations to better respect guard areas.

   - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
     of mem_cgroup_iter() and various code cleanups.

   - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
     pfnmap support.

   - "resource: Fix region_intersects() vs add_memory_driver_managed()"
     from Huang Ying. Fix a bug in region_intersects() for systems with
     CXL memory.

   - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
     a couple more code paths to correctly recover from the encountering
     of poisoned memry.

   - "mm: enable large folios swap-in support" from Barry Song. Support
     the swapin of mTHP memory into appropriately-sized folios, rather
     than into single-page folios"

* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
  zram: free secondary algorithms names
  uprobes: turn xol_area->pages[2] into xol_area->page
  uprobes: introduce the global struct vm_special_mapping xol_mapping
  Revert "uprobes: use vm_special_mapping close() functionality"
  mm: support large folios swap-in for sync io devices
  mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
  mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
  mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
  set_memory: add __must_check to generic stubs
  mm/vma: return the exact errno in vms_gather_munmap_vmas()
  memcg: cleanup with !CONFIG_MEMCG_V1
  mm/show_mem.c: report alloc tags in human readable units
  mm: support poison recovery from copy_present_page()
  mm: support poison recovery from do_cow_fault()
  resource, kunit: add test case for region_intersects()
  resource: make alloc_free_mem_region() works for iomem_resource
  mm: z3fold: deprecate CONFIG_Z3FOLD
  vfio/pci: implement huge_fault support
  mm/arm64: support large pfn mappings
  mm/x86: support large pfn mappings
  ...
2024-09-21 07:29:05 -07:00
Linus Torvalds
3352633ce6 vfs-6.12.file
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Merge tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs file updates from Christian Brauner:
 "This is the work to cleanup and shrink struct file significantly.

  Right now, (focusing on x86) struct file is 232 bytes. After this
  series struct file will be 184 bytes aka 3 cacheline and a spare 8
  bytes for future extensions at the end of the struct.

  With struct file being as ubiquitous as it is this should make a
  difference for file heavy workloads and allow further optimizations in
  the future.

   - struct fown_struct was embedded into struct file letting it take up
     32 bytes in total when really it shouldn't even be embedded in
     struct file in the first place. Instead, actual users of struct
     fown_struct now allocate the struct on demand. This frees up 24
     bytes.

   - Move struct file_ra_state into the union containg the cleanup hooks
     and move f_iocb_flags out of the union. This closes a 4 byte hole
     we created earlier and brings struct file to 192 bytes. Which means
     struct file is 3 cachelines and we managed to shrink it by 40
     bytes.

   - Reorder struct file so that nothing crosses a cacheline.

     I suspect that in the future we will end up reordering some members
     to mitigate false sharing issues or just because someone does
     actually provide really good perf data.

   - Shrinking struct file to 192 bytes is only part of the work.

     Files use a slab that is SLAB_TYPESAFE_BY_RCU and when a kmem cache
     is created with SLAB_TYPESAFE_BY_RCU the free pointer must be
     located outside of the object because the cache doesn't know what
     part of the memory can safely be overwritten as it may be needed to
     prevent object recycling.

     That has the consequence that SLAB_TYPESAFE_BY_RCU may end up
     adding a new cacheline.

     So this also contains work to add a new kmem_cache_create_rcu()
     function that allows the caller to specify an offset where the
     freelist pointer is supposed to be placed. Thus avoiding the
     implicit addition of a fourth cacheline.

   - And finally this removes the f_version member in struct file.

     The f_version member isn't particularly well-defined. It is mainly
     used as a cookie to detect concurrent seeks when iterating
     directories. But it is also abused by some subsystems for
     completely unrelated things.

     It is mostly a directory and filesystem specific thing that doesn't
     really need to live in struct file and with its wonky semantics it
     really lacks a specific function.

     For pipes, f_version is (ab)used to defer poll notifications until
     a write has happened. And struct pipe_inode_info is used by
     multiple struct files in their ->private_data so there's no chance
     of pushing that down into file->private_data without introducing
     another pointer indirection.

     But pipes don't rely on f_pos_lock so this adds a union into struct
     file encompassing f_pos_lock and a pipe specific f_pipe member that
     pipes can use. This union of course can be extended to other file
     types and is similar to what we do in struct inode already"

* tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  fs: remove f_version
  pipe: use f_pipe
  fs: add f_pipe
  ubifs: store cookie in private data
  ufs: store cookie in private data
  udf: store cookie in private data
  proc: store cookie in private data
  ocfs2: store cookie in private data
  input: remove f_version abuse
  ext4: store cookie in private data
  ext2: store cookie in private data
  affs: store cookie in private data
  fs: add generic_llseek_cookie()
  fs: use must_set_pos()
  fs: add must_set_pos()
  fs: add vfs_setpos_cookie()
  s390: remove unused f_version
  ceph: remove unused f_version
  adi: remove unused f_version
  mm: Removed @freeptr_offset to prevent doc warning
  ...
2024-09-16 09:14:02 +02:00
Linus Torvalds
2775df6e5e vfs-6.12.folio
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Merge tag 'vfs-6.12.folio' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull vfs folio updates from Christian Brauner:
 "This contains work to port write_begin and write_end to rely on folios
  for various filesystems.

  This converts ocfs2, vboxfs, orangefs, jffs2, hostfs, fuse, f2fs,
  ecryptfs, ntfs3, nilfs2, reiserfs, minixfs, qnx6, sysv, ufs, and
  squashfs.

  After this series lands a bunch of the filesystems in this list do not
  mention struct page anymore"

* tag 'vfs-6.12.folio' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (61 commits)
  Squashfs: Ensure all readahead pages have been used
  Squashfs: Rewrite and update squashfs_readahead_fragment() to not use page->index
  Squashfs: Update squashfs_readpage_block() to not use page->index
  Squashfs: Update squashfs_readahead() to not use page->index
  Squashfs: Update page_actor to not use page->index
  jffs2: Use a folio in jffs2_garbage_collect_dnode()
  jffs2: Convert jffs2_do_readpage_nolock to take a folio
  buffer: Convert __block_write_begin() to take a folio
  ocfs2: Convert ocfs2_write_zero_page to use a folio
  fs: Convert aops->write_begin to take a folio
  fs: Convert aops->write_end to take a folio
  vboxsf: Use a folio in vboxsf_write_end()
  orangefs: Convert orangefs_write_begin() to use a folio
  orangefs: Convert orangefs_write_end() to use a folio
  jffs2: Convert jffs2_write_begin() to use a folio
  jffs2: Convert jffs2_write_end() to use a folio
  hostfs: Convert hostfs_write_end() to use a folio
  fuse: Convert fuse_write_begin() to use a folio
  fuse: Convert fuse_write_end() to use a folio
  f2fs: Convert f2fs_write_begin() to use a folio
  ...
2024-09-16 08:54:30 +02:00
Linus Torvalds
8f72c31f45 vfs-6.12.misc
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Merge tag 'vfs-6.12.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual pile of misc updates:

  Features:

   - Add F_CREATED_QUERY fcntl() that allows userspace to query whether
     a file was actually created. Often userspace wants to know whether
     an O_CREATE request did actually create a file without using
     O_EXCL. The current logic is that to first attempts to open the
     file without O_CREAT | O_EXCL and if ENOENT is returned userspace
     tries again with both flags. If that succeeds all is well. If it
     now reports EEXIST it retries.

     That works fairly well but some corner cases make this more
     involved. If this operates on a dangling symlink the first openat()
     without O_CREAT | O_EXCL will return ENOENT but the second openat()
     with O_CREAT | O_EXCL will fail with EEXIST.

     The reason is that openat() without O_CREAT | O_EXCL follows the
     symlink while O_CREAT | O_EXCL doesn't for security reasons. So
     it's not something we can really change unless we add an explicit
     opt-in via O_FOLLOW which seems really ugly.

     All available workarounds are really nasty (fanotify, bpf lsm etc)
     so add a simple fcntl().

   - Try an opportunistic lookup for O_CREAT. Today, when opening a file
     we'll typically do a fast lookup, but if O_CREAT is set, the kernel
     always takes the exclusive inode lock. This was likely done with
     the expectation that O_CREAT means that we always expect to do the
     create, but that's often not the case. Many programs set O_CREAT
     even in scenarios where the file already exists (see related
     F_CREATED_QUERY patch motivation above).

     The series contained in the pr rearranges the pathwalk-for-open
     code to also attempt a fast_lookup in certain O_CREAT cases. If a
     positive dentry is found, the inode_lock can be avoided altogether
     and it can stay in rcuwalk mode for the last step_into.

   - Expose the 64 bit mount id via name_to_handle_at()

     Now that we provide a unique 64-bit mount ID interface in statx(2),
     we can now provide a race-free way for name_to_handle_at(2) to
     provide a file handle and corresponding mount without needing to
     worry about racing with /proc/mountinfo parsing or having to open a
     file just to do statx(2).

     While this is not necessary if you are using AT_EMPTY_PATH and
     don't care about an extra statx(2) call, users that pass full paths
     into name_to_handle_at(2) need to know which mount the file handle
     comes from (to make sure they don't try to open_by_handle_at a file
     handle from a different filesystem) and switching to AT_EMPTY_PATH
     would require allocating a file for every name_to_handle_at(2) call

   - Add a per dentry expire timeout to autofs

     There are two fairly well known automounter map formats, the autofs
     format and the amd format (more or less System V and Berkley).

     Some time ago Linux autofs added an amd map format parser that
     implemented a fair amount of the amd functionality. This was done
     within the autofs infrastructure and some functionality wasn't
     implemented because it either didn't make sense or required extra
     kernel changes. The idea was to restrict changes to be within the
     existing autofs functionality as much as possible and leave changes
     with a wider scope to be considered later.

     One of these changes is implementing the amd options:
      1) "unmount", expire this mount according to a timeout (same as
         the current autofs default).
      2) "nounmount", don't expire this mount (same as setting the
         autofs timeout to 0 except only for this specific mount) .
      3) "utimeout=<seconds>", expire this mount using the specified
         timeout (again same as setting the autofs timeout but only for
         this mount)

     To implement these options per-dentry expire timeouts need to be
     implemented for autofs indirect mounts. This is because all map
     keys (mounts) for autofs indirect mounts use an expire timeout
     stored in the autofs mount super block info. structure and all
     indirect mounts use the same expire timeout.

  Fixes:

   - Fix missing fput for FSCONFIG_SET_FD in autofs

   - Use param->file for FSCONFIG_SET_FD in coda

   - Delete the 'fs/netfs' proc subtreee when netfs module exits

   - Make sure that struct uid_gid_map fits into a single cacheline

   - Don't flush in-flight wb switches for superblocks without cgroup
     writeback

   - Correcting the idmapping mount example in the idmapping
     documentation

   - Fix a race between evice_inodes() and find_inode() and iput()

   - Refine the show_inode_state() macro definition in writeback code

   - Prevent dump_mapping() from accessing invalid dentry.d_name.name

   - Show actual source for debugfs in /proc/mounts

   - Annotate data-race of busy_poll_usecs in eventpoll

   - Don't WARN for racy path_noexec check in exec code

   - Handle OOM on mnt_warn_timestamp_expiry()

   - Fix some spelling in the iomap design documentation

   - Fix typo in procfs comment

   - Fix typo in fs/namespace.c comment

  Cleanups:

   - Add the VFS git tree to the MAINTAINERS file

   - Move FMODE_UNSIGNED_OFFSET to fop_flags freeing up another f_mode
     bit in struct file bringing us to 5 free f_mode bits

   - Remove the __I_DIO_WAKEUP bit from i_state flags as we can simplify
     the wait mechanism

   - Remove the unused path_put_init() helper

   - Replace a __u32 with u32 for s_fsnotify_mask as __u32 is uapi
     specific

   - Replace the unsigned long i_state member with a u32 i_state member
     in struct inode freeing up 4 bytes in struct inode. Instead of
     using the bit based wait apis we're now using the var event apis
     and using the individual bytes of the i_state member to wait on
     state changes

   - Explain how per-syscall AT_* flags should be allocated

   - Use in_group_or_capable() helper to simplify the posix acl mode
     update code

   - Switch to LIST_HEAD() in fsync_buffers_list() to simplify the code

   - Removed comment about d_rcu_to_refcount() as that function doesn't
     exist anymore

   - Add kernel documentation for lookup_fast()

   - Don't re-zero evenpoll fields

   - Remove outdated comment after close_fd()

   - Fix imprecise wording in comment about the pipe filesystem

   - Drop GFP_NOFAIL mode from alloc_page_buffers

   - Missing blank line warnings and struct declaration improved in
     file_table

   - Annotate struct poll_list with __counted_by()

   - Remove the unused read parameter in percpu-rwsem

   - Remove linux/prefetch.h include from direct-io code

   - Use kmemdup_array instead of kmemdup for multiple allocation in
     mnt_idmapping code

   - Remove unused mnt_cursor_del() declaration

  Performance tweaks:

   - Dodge smp_mb in break_lease and break_deleg in the common case

   - Only read fops once in fops_{get,put}()

   - Use RCU in ilookup()

   - Elide smp_mb in iversion handling in the common case

   - Drop one lock trip in evict()"

* tag 'vfs-6.12.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (58 commits)
  uidgid: make sure we fit into one cacheline
  proc: Fix typo in the comment
  fs/pipe: Correct imprecise wording in comment
  fhandle: expose u64 mount id to name_to_handle_at(2)
  uapi: explain how per-syscall AT_* flags should be allocated
  fs: drop GFP_NOFAIL mode from alloc_page_buffers
  writeback: Refine the show_inode_state() macro definition
  fs/inode: Prevent dump_mapping() accessing invalid dentry.d_name.name
  mnt_idmapping: Use kmemdup_array instead of kmemdup for multiple allocation
  netfs: Delete subtree of 'fs/netfs' when netfs module exits
  fs: use LIST_HEAD() to simplify code
  inode: make i_state a u32
  inode: port __I_LRU_ISOLATING to var event
  vfs: fix race between evice_inodes() and find_inode()&iput()
  inode: port __I_NEW to var event
  inode: port __I_SYNC to var event
  fs: reorder i_state bits
  fs: add i_state helpers
  MAINTAINERS: add the VFS git tree
  fs: s/__u32/u32/ for s_fsnotify_mask
  ...
2024-09-16 08:35:09 +02:00
Benjamin Coddington
8cf9a01edc
fs: Introduce FOP_ASYNC_LOCK
Some lock managers (NLM, kNFSD) fastidiously avoid blocking their
kernel threads while servicing blocking locks.  If a filesystem supports
asynchronous lock requests those lock managers can use notifications to
quickly inform clients they have acquired a file lock.

Historically, only posix_lock_file() was capable of supporting asynchronous
locks so the check for support was simply file_operations->lock(), but with
recent changes in DLM, both GFS2 and OCFS2 also support asynchronous locks
and have started signalling their support with EXPORT_OP_ASYNC_LOCK.

We recently noticed that those changes dropped the checks for whether a
filesystem simply defaults to posix_lock_file(), so async lock
notifications have not been attempted for NLM and NFSv4.1+ for most
filesystems.  While trying to fix this it has become clear that testing
both the export flag combined with testing ->lock() creates quite a
layering mess.  It seems appropriate to signal support with a fop_flag.

Add FOP_ASYNC_LOCK so that filesystems with ->lock() can signal their
capability to handle lock requests asynchronously.  Add a helper for
lock managers to properly test that support.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Link: https://lore.kernel.org/r/3330d5a324abe2ce9c1dafe89cacdc6db41945d1.1726083391.git.bcodding@redhat.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-12 14:39:05 +02:00
Christian Brauner
11068e0b64
fs: remove f_version
Now that detecting concurrent seeks is done by the filesystems that
require it we can remove f_version and free up 8 bytes for future
extensions.

Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-20-6d3e4816aa7b@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-12 11:58:45 +02:00
Christian Brauner
5e9b50dea9
fs: add f_pipe
Only regular files with FMODE_ATOMIC_POS and directories need
f_pos_lock. Place a new f_pipe member in a union with f_pos_lock
that they can use and make them stop abusing f_version in follow-up
patches.

Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-18-6d3e4816aa7b@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-12 11:58:45 +02:00
Kent Overstreet
88d2ae0e6e inode: make __iget() a static inline
bcachefs is switching to an rhashtable for vfs inodes instead of the
standard inode.c hashtable, so we need this exported, or - a static
inline makes more sense for a single atomic_inc().

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-09-09 09:41:47 -04:00
Christian Brauner
d688d65a84
fs: add generic_llseek_cookie()
This is similar to generic_file_llseek() but allows the caller to
specify a cookie that will be updated to indicate that a seek happened.
Caller's requiring that information in their readdir implementations can
use that.

Link: https://lore.kernel.org/r/20240830-vfs-file-f_version-v1-8-6d3e4816aa7b@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-09 11:58:07 +02:00
Alexander Mikhalitsyn
2097154a10 namespace: introduce SB_I_NOIDMAP flag
Right now we determine if filesystem support vfs idmappings or not basing
on the FS_ALLOW_IDMAP flag presence. This "static" way works perfecly well
for local filesystems like ext4, xfs, btrfs, etc. But for network-like
filesystems like fuse, cephfs this approach is not ideal, because sometimes
proper support of vfs idmaps requires some extensions for the on-wire
protocol, which implies that changes have to be made not only in the Linux
kernel code but also in the 3rd party components like libfuse, cephfs MDS
server and so on.

We have seen that issue during our work on cephfs idmapped mounts [1] with
Christian, but right now I'm working on the idmapped mounts support for
fuse/virtiofs and I think that it is a right time for this extension.

[1] 5ccd8530dd ("ceph: handle idmapped mounts in create_request_message()")

Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2024-09-04 16:47:49 +02:00
Yafang Shao
0a2d82946b mm: allow read-ahead with IOCB_NOWAIT set
Readahead support for IOCB_NOWAIT was introduced in commit 2e85abf053
("mm: allow read-ahead with IOCB_NOWAIT set").  However, this
implementation broke the semantics of IOCB_NOWAIT by potentially causing
it to wait on I/O during memory reclamation.  This behavior was later
modified in commit efa8480a83 ("fs: RWF_NOWAIT should imply IOCB_NOIO").

To resolve the blocking issue during memory reclamation, we can use
memalloc_noio_{save,restore} to ensure non-blocking behavior.  This change
restores the original functionality, allowing preadv2(IOCB_NOWAIT) to
trigger readahead if the file content is not present in the page cache.

While this process may trigger direct memory reclamation, the
__GFP_NORETRY flag is set in the readahead GFP flags, ensuring it won't
block.

A use case for this change is when we want to trigger readahead in the
preadv2(2) syscall if the file cache is absent, but without waiting for
certain filesystem locks, like xfs_ilock.  A simple example is as follows:

retry:
    if (preadv2(fd, iovec, cnt, offset, RWF_NOWAIT) < 0) {
        do_other_work();
        goto retry;
    }

Link: https://lore.gnuweeb.org/io-uring/20200624164127.GP21350@casper.infradead.org/
Link: https://lkml.kernel.org/r/20240820022639.89562-1-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-03 21:15:40 -07:00
Christian Brauner
2b111edbe0 inode: make i_state a u32
Now that we use the wait var event mechanism make i_state a u32 and free
up 4 bytes. This means we currently have two 4 byte holes in struct
inode which we can pack.

Link: https://lore.kernel.org/r/20240823-work-i_state-v3-6-5cd5fd207a57@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:40 +02:00
Christian Brauner
2ed634c96e fs: reorder i_state bits
so that we can use the first bits to derive unique addresses from
i_state.

Link: https://lore.kernel.org/r/20240823-work-i_state-v3-2-5cd5fd207a57@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:39 +02:00
Christian Brauner
da18ecbf0f fs: add i_state helpers
The i_state member is an unsigned long so that it can be used with the
wait bit infrastructure which expects unsigned long. This wastes 4 bytes
which we're unlikely to ever use. Switch to using the var event wait
mechanism using the address of the bit. Thanks to Linus for the address
idea.

Link: https://lore.kernel.org/r/20240823-work-i_state-v3-1-5cd5fd207a57@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:39 +02:00
Christian Brauner
71ff58ce34 fs: s/__u32/u32/ for s_fsnotify_mask
The underscore variants are for uapi whereas the non-underscore variants
are for in-kernel consumers.

Link: https://lore.kernel.org/r/20240822-anwerben-nutzung-1cd6c82a565f@brauner
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:38 +02:00
Christian Brauner
1c48d44146 inode: remove __I_DIO_WAKEUP
Afaict, we can just rely on inode->i_dio_count for waiting instead of
this awkward indirection through __I_DIO_WAKEUP. This survives LTP dio
and xfstests dio tests.

Link: https://lore.kernel.org/r/20240816-vfs-misc-dio-v1-1-80fe21a2c710@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:37 +02:00
Christian Brauner
641bb4394f fs: move FMODE_UNSIGNED_OFFSET to fop_flags
This is another flag that is statically set and doesn't need to use up
an FMODE_* bit. Move it to ->fop_flags and free up another FMODE_* bit.

(1) mem_open() used from proc_mem_operations
(2) adi_open() used from adi_fops
(3) drm_open_helper():
    (3.1) accel_open() used from DRM_ACCEL_FOPS
    (3.2) drm_open() used from
    (3.2.1) amdgpu_driver_kms_fops
    (3.2.2) psb_gem_fops
    (3.2.3) i915_driver_fops
    (3.2.4) nouveau_driver_fops
    (3.2.5) panthor_drm_driver_fops
    (3.2.6) radeon_driver_kms_fops
    (3.2.7) tegra_drm_fops
    (3.2.8) vmwgfx_driver_fops
    (3.2.9) xe_driver_fops
    (3.2.10) DRM_GEM_FOPS
    (3.2.11) DEFINE_DRM_GEM_DMA_FOPS
(4) struct memdev sets fmode flags based on type of device opened. For
    devices using struct mem_fops unsigned offset is used.

Mark all these file operations as FOP_UNSIGNED_OFFSET and add asserts
into the open helper to ensure that the flag is always set.

Link: https://lore.kernel.org/r/20240809-work-fop_unsigned-v1-1-658e054d893e@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:36 +02:00
Mateusz Guzik
8447d848e1 vfs: only read fops once in fops_get/put
In do_dentry_open() the usage is:
	f->f_op = fops_get(inode->i_fop);

In generated asm the compiler emits 2 reads from inode->i_fop instead of
just one.

This popped up due to false-sharing where loads from that offset end up
bouncing a cacheline during parallel open. While this is going to be fixed,
the spurious load does not need to be there.

This makes do_dentry_open() go down from 1177 to 1154 bytes.

fops_put() is patched to maintain some consistency.

No functional changes.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240810064753.1211441-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-30 08:22:36 +02:00
Christian Brauner
ea566e18b4 fs: use kmem_cache_create_rcu()
Switch to the new kmem_cache_create_rcu() helper which allows us to use
a custom free pointer offset avoiding the need to have an external free
pointer which would grow struct file behind our backs.

Link: https://lore.kernel.org/r/20240828-work-kmem_cache-rcu-v3-3-5460bc1f09f6@kernel.org
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-29 15:20:33 +02:00
Christian Brauner
c0390d5411 fs: pack struct file
Now that we shrunk struct file to 192 bytes aka 3 cachelines reorder
struct file to not leave any holes or have members cross cachelines.

Add a short comment to each of the fields and mark the cachelines.
It's possible that we may have to tweak this based on profiling in the
future. So far I had Jens test this comparing io_uring with non-fixed
and fixed files and it improved performance. The layout is a combination
of Jens' and my changes.

Link: https: //lore.kernel.org/r/20240824-peinigen-hocken-7384b977c643@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-29 15:20:25 +02:00
Linus Torvalds
a18093afa3 nfsd-6.11 fixes:
- Fix a number of crashers
 - Update email address for an NFSD reviewer
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Merge tag 'nfsd-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd fixes from Chuck Lever:

 - Fix a number of crashers

 - Update email address for an NFSD reviewer

* tag 'nfsd-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  fs/nfsd: fix update of inode attrs in CB_GETATTR
  nfsd: fix potential UAF in nfsd4_cb_getattr_release
  nfsd: hold reference to delegation when updating it for cb_getattr
  MAINTAINERS: Update Olga Kornievskaia's email address
  nfsd: prevent panic for nfsv4.0 closed files in nfs4_show_open
  nfsd: ensure that nfsd4_fattr_args.context is zeroed out
2024-08-29 06:20:44 +12:00
Christian Brauner
a55d1cbd17 fs: switch f_iocb_flags and f_ra
Now that we shrank struct file by 24 bytes we still have a 4 byte hole.
If we move struct file_ra_state into the union and f_iocb_flags out of
the union we close that whole and bring down struct file to 192 bytes.
Which means struct file is 3 cachelines and we managed to shrink it by
40 bytes this cycle.

I've tried to audit all codepaths that use f_ra and none of them seem to
rely on it in file->f_op->release() and never have since commit
1da177e4c3 ("Linux-2.6.12-rc2").

Link: https://lore.kernel.org/r/20240823-luftdicht-berappen-d69a2166a0db@brauner
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-28 13:06:12 +02:00
Christian Brauner
1934b21261 file: reclaim 24 bytes from f_owner
We do embedd struct fown_struct into struct file letting it take up 32
bytes in total. We could tweak struct fown_struct to be more compact but
really it shouldn't even be embedded in struct file in the first place.

Instead, actual users of struct fown_struct should allocate the struct
on demand. This frees up 24 bytes in struct file.

That will have some potentially user-visible changes for the ownership
fcntl()s. Some of them can now fail due to allocation failures.
Practically, that probably will almost never happen as the allocations
are small and they only happen once per file.

The fown_struct is used during kill_fasync() which is used by e.g.,
pipes to generate a SIGIO signal. Sending of such signals is conditional
on userspace having set an owner for the file using one of the F_OWNER
fcntl()s. Such users will be unaffected if struct fown_struct is
allocated during the fcntl() call.

There are a few subsystems that call __f_setown() expecting
file->f_owner to be allocated:

(1) tun devices
    file->f_op->fasync::tun_chr_fasync()
    -> __f_setown()

    There are no callers of tun_chr_fasync().

(2) tty devices

    file->f_op->fasync::tty_fasync()
    -> __tty_fasync()
       -> __f_setown()

    tty_fasync() has no additional callers but __tty_fasync() has. Note
    that __tty_fasync() only calls __f_setown() if the @on argument is
    true. It's called from:

    file->f_op->release::tty_release()
    -> tty_release()
       -> __tty_fasync()
          -> __f_setown()

    tty_release() calls __tty_fasync() with @on false
    => __f_setown() is never called from tty_release().
       => All callers of tty_release() are safe as well.

    file->f_op->release::tty_open()
    -> tty_release()
       -> __tty_fasync()
          -> __f_setown()

    __tty_hangup() calls __tty_fasync() with @on false
    => __f_setown() is never called from tty_release().
       => All callers of __tty_hangup() are safe as well.

From the callchains it's obvious that (1) and (2) end up getting called
via file->f_op->fasync(). That can happen either through the F_SETFL
fcntl() with the FASYNC flag raised or via the FIOASYNC ioctl(). If
FASYNC is requested and the file isn't already FASYNC then
file->f_op->fasync() is called with @on true which ends up causing both
(1) and (2) to call __f_setown().

(1) and (2) are the only subsystems that call __f_setown() from the
file->f_op->fasync() handler. So both (1) and (2) have been updated to
allocate a struct fown_struct prior to calling fasync_helper() to
register with the fasync infrastructure. That's safe as they both call
fasync_helper() which also does allocations if @on is true.

The other interesting case are file leases:

(3) file leases
    lease_manager_ops->lm_setup::lease_setup()
    -> __f_setown()

    Which in turn is called from:

    generic_add_lease()
    -> lease_manager_ops->lm_setup::lease_setup()
       -> __f_setown()

So here again we can simply make generic_add_lease() allocate struct
fown_struct prior to the lease_manager_ops->lm_setup::lease_setup()
which happens under a spinlock.

With that the two remaining subsystems that call __f_setown() are:

(4) dnotify
(5) sockets

Both have their own custom ioctls to set struct fown_struct and both
have been converted to allocate a struct fown_struct on demand from
their respective ioctls.

Interactions with O_PATH are fine as well e.g., when opening a /dev/tty
as O_PATH then no file->f_op->open() happens thus no file->f_owner is
allocated. That's fine as no file operation will be set for those and
the device has never been opened. fcntl()s called on such things will
just allocate a ->f_owner on demand. Although I have zero idea why'd you
care about f_owner on an O_PATH fd.

Link: https://lore.kernel.org/r/20240813-work-f_owner-v2-1-4e9343a79f9f@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-28 13:05:39 +02:00
Jeff Layton
7e8ae8486e fs/nfsd: fix update of inode attrs in CB_GETATTR
Currently, we copy the mtime and ctime to the in-core inode and then
mark the inode dirty. This is fine for certain types of filesystems, but
not all. Some require a real setattr to properly change these values
(e.g. ceph or reexported NFS).

Fix this code to call notify_change() instead, which is the proper way
to effect a setattr. There is one problem though:

In this case, the client is holding a write delegation and has sent us
attributes to update our cache. We don't want to break the delegation
for this since that would defeat the purpose. Add a new ATTR_DELEG flag
that makes notify_change bypass the try_break_deleg call.

Fixes: c5967721e1 ("NFSD: handle GETATTR conflict with write delegation")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-08-26 19:04:00 -04:00
Wang Long
c01a5d89e5 percpu-rwsem: remove the unused parameter 'read'
In the function percpu_rwsem_release, the parameter `read`
is unused, so remove it.

Signed-off-by: Wang Long <w@laoqinren.net>
Link: https://lore.kernel.org/r/20240802091901.2546797-1-w@laoqinren.net
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-19 13:45:03 +02:00
Zhihao Cheng
2a0629834c
vfs: Don't evict inode under the inode lru traversing context
The inode reclaiming process(See function prune_icache_sb) collects all
reclaimable inodes and mark them with I_FREEING flag at first, at that
time, other processes will be stuck if they try getting these inodes
(See function find_inode_fast), then the reclaiming process destroy the
inodes by function dispose_list(). Some filesystems(eg. ext4 with
ea_inode feature, ubifs with xattr) may do inode lookup in the inode
evicting callback function, if the inode lookup is operated under the
inode lru traversing context, deadlock problems may happen.

Case 1: In function ext4_evict_inode(), the ea inode lookup could happen
        if ea_inode feature is enabled, the lookup process will be stuck
	under the evicting context like this:

 1. File A has inode i_reg and an ea inode i_ea
 2. getfattr(A, xattr_buf) // i_ea is added into lru // lru->i_ea
 3. Then, following three processes running like this:

    PA                              PB
 echo 2 > /proc/sys/vm/drop_caches
  shrink_slab
   prune_dcache_sb
   // i_reg is added into lru, lru->i_ea->i_reg
   prune_icache_sb
    list_lru_walk_one
     inode_lru_isolate
      i_ea->i_state |= I_FREEING // set inode state
     inode_lru_isolate
      __iget(i_reg)
      spin_unlock(&i_reg->i_lock)
      spin_unlock(lru_lock)
                                     rm file A
                                      i_reg->nlink = 0
      iput(i_reg) // i_reg->nlink is 0, do evict
       ext4_evict_inode
        ext4_xattr_delete_inode
         ext4_xattr_inode_dec_ref_all
          ext4_xattr_inode_iget
           ext4_iget(i_ea->i_ino)
            iget_locked
             find_inode_fast
              __wait_on_freeing_inode(i_ea) ----→ AA deadlock
    dispose_list // cannot be executed by prune_icache_sb
     wake_up_bit(&i_ea->i_state)

Case 2: In deleted inode writing function ubifs_jnl_write_inode(), file
        deleting process holds BASEHD's wbuf->io_mutex while getting the
	xattr inode, which could race with inode reclaiming process(The
        reclaiming process could try locking BASEHD's wbuf->io_mutex in
	inode evicting function), then an ABBA deadlock problem would
	happen as following:

 1. File A has inode ia and a xattr(with inode ixa), regular file B has
    inode ib and a xattr.
 2. getfattr(A, xattr_buf) // ixa is added into lru // lru->ixa
 3. Then, following three processes running like this:

        PA                PB                        PC
                echo 2 > /proc/sys/vm/drop_caches
                 shrink_slab
                  prune_dcache_sb
                  // ib and ia are added into lru, lru->ixa->ib->ia
                  prune_icache_sb
                   list_lru_walk_one
                    inode_lru_isolate
                     ixa->i_state |= I_FREEING // set inode state
                    inode_lru_isolate
                     __iget(ib)
                     spin_unlock(&ib->i_lock)
                     spin_unlock(lru_lock)
                                                   rm file B
                                                    ib->nlink = 0
 rm file A
  iput(ia)
   ubifs_evict_inode(ia)
    ubifs_jnl_delete_inode(ia)
     ubifs_jnl_write_inode(ia)
      make_reservation(BASEHD) // Lock wbuf->io_mutex
      ubifs_iget(ixa->i_ino)
       iget_locked
        find_inode_fast
         __wait_on_freeing_inode(ixa)
          |          iput(ib) // ib->nlink is 0, do evict
          |           ubifs_evict_inode
          |            ubifs_jnl_delete_inode(ib)
          ↓             ubifs_jnl_write_inode
     ABBA deadlock ←-----make_reservation(BASEHD)
                   dispose_list // cannot be executed by prune_icache_sb
                    wake_up_bit(&ixa->i_state)

Fix the possible deadlock by using new inode state flag I_LRU_ISOLATING
to pin the inode in memory while inode_lru_isolate() reclaims its pages
instead of using ordinary inode reference. This way inode deletion
cannot be triggered from inode_lru_isolate() thus avoiding the deadlock.
evict() is made to wait for I_LRU_ISOLATING to be cleared before
proceeding with inode cleanup.

Link: https://lore.kernel.org/all/37c29c42-7685-d1f0-067d-63582ffac405@huaweicloud.com/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219022
Fixes: e50e5129f3 ("ext4: xattr-in-inode support")
Fixes: 7959cf3a75 ("ubifs: journal: Handle xattrs like files")
Cc: stable@vger.kernel.org
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Link: https://lore.kernel.org/r/20240809031628.1069873-1-chengzhihao@huaweicloud.com
Reviewed-by: Jan Kara <jack@suse.cz>
Suggested-by: Jan Kara <jack@suse.cz>
Suggested-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-13 13:52:16 +02:00
Matthew Wilcox (Oracle)
1da86618bd
fs: Convert aops->write_begin to take a folio
Convert all callers from working on a page to working on one page
of a folio (support for working on an entire folio can come later).
Removes a lot of folio->page->folio conversions.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-07 11:33:21 +02:00
Matthew Wilcox (Oracle)
a225800f32
fs: Convert aops->write_end to take a folio
Most callers have a folio, and most implementations operate on a folio,
so remove the conversion from folio->page->folio to fit through this
interface.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-07 11:32:02 +02:00
Linus Torvalds
3e78198862 for-6.11/block-20240710
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Merge tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux

Pull block updates from Jens Axboe:

 - NVMe updates via Keith:
     - Device initialization memory leak fixes (Keith)
     - More constants defined (Weiwen)
     - Target debugfs support (Hannes)
     - PCIe subsystem reset enhancements (Keith)
     - Queue-depth multipath policy (Redhat and PureStorage)
     - Implement get_unique_id (Christoph)
     - Authentication error fixes (Gaosheng)

 - MD updates via Song
     - sync_action fix and refactoring (Yu Kuai)
     - Various small fixes (Christoph Hellwig, Li Nan, and Ofir Gal, Yu
       Kuai, Benjamin Marzinski, Christophe JAILLET, Yang Li)

 - Fix loop detach/open race (Gulam)

 - Fix lower control limit for blk-throttle (Yu)

 - Add module descriptions to various drivers (Jeff)

 - Add support for atomic writes for block devices, and statx reporting
   for same. Includes SCSI and NVMe (John, Prasad, Alan)

 - Add IO priority information to block trace points (Dongliang)

 - Various zone improvements and tweaks (Damien)

 - mq-deadline tag reservation improvements (Bart)

 - Ignore direct reclaim swap writes in writeback throttling (Baokun)

 - Block integrity improvements and fixes (Anuj)

 - Add basic support for rust based block drivers. Has a dummy null_blk
   variant for now (Andreas)

 - Series converting driver settings to queue limits, and cleanups and
   fixes related to that (Christoph)

 - Cleanup for poking too deeply into the bvec internals, in preparation
   for DMA mapping API changes (Christoph)

 - Various minor tweaks and fixes (Jiapeng, John, Kanchan, Mikulas,
   Ming, Zhu, Damien, Christophe, Chaitanya)

* tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux: (206 commits)
  floppy: add missing MODULE_DESCRIPTION() macro
  loop: add missing MODULE_DESCRIPTION() macro
  ublk_drv: add missing MODULE_DESCRIPTION() macro
  xen/blkback: add missing MODULE_DESCRIPTION() macro
  block/rnbd: Constify struct kobj_type
  block: take offset into account in blk_bvec_map_sg again
  block: fix get_max_segment_size() warning
  loop: Don't bother validating blocksize
  virtio_blk: Don't bother validating blocksize
  null_blk: Don't bother validating blocksize
  block: Validate logical block size in blk_validate_limits()
  virtio_blk: Fix default logical block size fallback
  nvmet-auth: fix nvmet_auth hash error handling
  nvme: implement ->get_unique_id
  block: pass a phys_addr_t to get_max_segment_size
  block: add a bvec_phys helper
  blk-lib: check for kill signal in ioctl BLKZEROOUT
  block: limit the Write Zeroes to manually writing zeroes fallback
  block: refacto blkdev_issue_zeroout
  block: move read-only and supported checks into (__)blkdev_issue_zeroout
  ...
2024-07-15 14:20:22 -07:00
Linus Torvalds
2aae1d67fd vfs-6.11.inode
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Merge tag 'vfs-6.11.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs inode / dentry updates from Christian Brauner:
 "This contains smaller performance improvements to inodes and dentries:

  inode:

   - Add rcu based inode lookup variants.

     They avoid one inode hash lock acquire in the common case thereby
     significantly reducing contention. We already support RCU-based
     operations but didn't take advantage of them during inode
     insertion.

     Callers of iget_locked() get the improvement without any code
     changes. Callers that need a custom callback can switch to
     iget5_locked_rcu() as e.g., did btrfs.

     With 20 threads each walking a dedicated 1000 dirs * 1000 files
     directory tree to stat(2) on a 32 core + 24GB ram vm:

        before: 3.54s user 892.30s system 1966% cpu 45.549 total
        after:  3.28s user 738.66s system 1955% cpu 37.932 total (-16.7%)

     Long-term we should pick up the effort to introduce more
     fine-grained locking and possibly improve on the currently used
     hash implementation.

   - Start zeroing i_state in inode_init_always() instead of doing it in
     individual filesystems.

     This allows us to remove an unneeded lock acquire in new_inode()
     and not burden individual filesystems with this.

  dcache:

   - Move d_lockref out of the area used by RCU lookup to avoid
     cacheline ping poing because the embedded name is sharing a
     cacheline with d_lockref.

   - Fix dentry size on 32bit with CONFIG_SMP=y so it does actually end
     up with 128 bytes in total"

* tag 'vfs-6.11.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: fix dentry size
  vfs: move d_lockref out of the area used by RCU lookup
  bcachefs: remove now spurious i_state initialization
  xfs: remove now spurious i_state initialization in xfs_inode_alloc
  vfs: partially sanitize i_state zeroing on inode creation
  xfs: preserve i_state around inode_init_always in xfs_reinit_inode
  btrfs: use iget5_locked_rcu
  vfs: add rcu-based find_inode variants for iget ops
2024-07-15 11:39:44 -07:00
Linus Torvalds
4a051e4c21 vfs-6.11.casefold
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Merge tag 'vfs-6.11.casefold' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs casefolding updates from Christian Brauner:
 "This contains some work to simplify the handling of casefolded names:

   - Simplify the handling of casefolded names in f2fs and ext4 by
     keeping the names as a qstr to avoiding unnecessary conversions

   - Introduce a new generic_ci_match() libfs case-insensitive lookup
     helper and use it in both f2fs and ext4 allowing to remove the
     filesystem specific implementations

   - Remove a bunch of ifdefs by making the unicode build checks part of
     the code flow"

* tag 'vfs-6.11.casefold' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  f2fs: Move CONFIG_UNICODE defguards into the code flow
  ext4: Move CONFIG_UNICODE defguards into the code flow
  f2fs: Reuse generic_ci_match for ci comparisons
  ext4: Reuse generic_ci_match for ci comparisons
  libfs: Introduce case-insensitive string comparison helper
  f2fs: Simplify the handling of cached casefolded names
  ext4: Simplify the handling of cached casefolded names
2024-07-15 11:18:49 -07:00
Mateusz Guzik
f378ec4eec
vfs: rename parent_ino to d_parent_ino and make it use RCU
The routine is used by procfs through dir_emit_dots.

The combined RCU and lock fallback implementation is too big for an
inline. Given that the routine takes a dentry argument fs/dcache.c seems
like the place to put it in.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240627161152.802567-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-27 18:34:21 +02:00
Christian Brauner
1bc6d4452d
fs: new helper vfs_empty_path()
Make it possible to quickly check whether AT_EMPTY_PATH is valid.
Note, after some discussion we decided to also allow NULL to be passed
instead of requiring the empty string.

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-27 18:31:19 +02:00
Youling Tang
9b6a14f08b
fs: Export in_group_or_capable()
Export in_group_or_capable() as a VFS helper function.

Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Link: https://lore.kernel.org/r/20240620032335.147136-1-youling.tang@linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-25 11:15:48 +02:00
Prasad Singamsetty
0f9ca80fa4 fs: Add initial atomic write support info to statx
Extend statx system call to return additional info for atomic write support
support for a file.

Helper function generic_fill_statx_atomic_writes() can be used by FSes to
fill in the relevant statx fields. For now atomic_write_segments_max will
always be 1, otherwise some rules would need to be imposed on iovec length
and alignment, which we don't want now.

Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com>
jpg: relocate bdev support to another patch
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20240620125359.2684798-5-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 15:19:17 -06:00
Prasad Singamsetty
c34fc6f26a fs: Initial atomic write support
An atomic write is a write issued with torn-write protection, meaning
that for a power failure or any other hardware failure, all or none of the
data from the write will be stored, but never a mix of old and new data.

Userspace may add flag RWF_ATOMIC to pwritev2() to indicate that the
write is to be issued with torn-write prevention, according to special
alignment and length rules.

For any syscall interface utilizing struct iocb, add IOCB_ATOMIC for
iocb->ki_flags field to indicate the same.

A call to statx will give the relevant atomic write info for a file:
- atomic_write_unit_min
- atomic_write_unit_max
- atomic_write_segments_max

Both min and max values must be a power-of-2.

Applications can avail of atomic write feature by ensuring that the total
length of a write is a power-of-2 in size and also sized between
atomic_write_unit_min and atomic_write_unit_max, inclusive. Applications
must ensure that the write is at a naturally-aligned offset in the file
wrt the total write length. The value in atomic_write_segments_max
indicates the upper limit for IOV_ITER iovcnt.

Add file mode flag FMODE_CAN_ATOMIC_WRITE, so files which do not have the
flag set will have RWF_ATOMIC rejected and not just ignored.

Add a type argument to kiocb_set_rw_flags() to allows reads which have
RWF_ATOMIC set to be rejected.

Helper function generic_atomic_write_valid() can be used by FSes to verify
compliant writes. There we check for iov_iter type is for ubuf, which
implies iovcnt==1 for pwritev2(), which is an initial restriction for
atomic_write_segments_max. Initially the only user will be bdev file
operations write handler. We will rely on the block BIO submission path to
ensure write sizes are compliant for the bdev, so we don't need to check
atomic writes sizes yet.

Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com>
jpg: merge into single patch and much rewrite
Acked-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20240620125359.2684798-4-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 15:19:17 -06:00
Mateusz Guzik
7180f8d91f vfs: add rcu-based find_inode variants for iget ops
This avoids one inode hash lock acquire in the common case on inode
creation, in effect significantly reducing contention.

On the stock kernel said lock is typically taken twice:
1. once to check if the inode happens to already be present
2. once to add it to the hash

The back-to-back lock/unlock pattern is known to degrade performance
significantly, which is further exacerbated if the hash is heavily
populated (long chains to walk, extending hold time). Arguably hash
sizing and hashing algo need to be revisited, but that's beyond the
scope of this patch.

With the acquire from step 1 eliminated with RCU lookup throughput
increases significantly at the scale of 20 cores (benchmark results at
the bottom).

So happens the hash already supports RCU-based operation, but lookups on
inode insertions didn't take advantage of it.

This of course has its limits as the global lock is still a bottleneck.
There was a patchset posted which introduced fine-grained locking[1] but
it appears staled. Apart from that doubt was expressed whether a
handrolled hash implementation is appropriate to begin with, suggesting
replacement with rhashtables. Nobody committed to carrying [1] across
the finish line or implementing anything better, thus the bandaid below.

iget_locked consumers (notably ext4) get away without any changes
because inode comparison method is built-in.

iget5_locked consumers pass a custom callback. Since removal of locking
adds more problems (inode can be changing) it's not safe to assume all
filesystems happen to cope.  Thus iget5_locked_rcu gets added, requiring
manual conversion of interested filesystems.

In order to reduce code duplication find_inode and find_inode_fast grow
an argument indicating whether inode hash lock is held, which is passed
down in case sleeping is necessary. They always rcu_read_lock, which is
redundant but harmless. Doing it conditionally reduces readability for
no real gain that I can see. RCU-alike restrictions were already put on
callbacks due to the hash spinlock being held.

Benchmarking:
There is a real cache-busting workload scanning millions of files in
parallel (it's a backup appliance), where the initial lookup is
guaranteed to fail resulting in the two lock acquires on stock kernel
(and one with the patch at hand).

Implemented below is a synthetic benchmark providing the same behavior.
[I shall note the workload is not running on Linux, instead it was
causing trouble elsewhere. Benchmark below was used while addressing
said problems and was found to adequately represent the real workload.]

Total real time fluctuates by 1-2s.

With 20 threads each walking a dedicated 1000 dirs * 1000 files
directory tree to stat(2) on a 32 core + 24GB RAM vm:

ext4 (needed mkfs.ext4 -N 24000000):
before: 3.77s user 890.90s system 1939% cpu 46.118 total
after:  3.24s user 397.73s system 1858% cpu 21.581 total (-53%)

That's 20 million files to visit, while the machine can only cache about
15 million at a time (obtained from ext4_inode_cache object count in
/proc/slabinfo). Since each terminal inode is only visited once per run
this amounts to 0% hit ratio for the dentry cache and the hash table
(there are however hits for the intermediate directories).

On repeated runs the kernel caches the last ~15 mln, meaning there is ~5
mln of uncached inodes which are going to be visited first, evicting the
previously cached state as it happens.

Lack of hits can be trivially verified with bpftrace, like so:
bpftrace -e 'kretprobe:find_inode_fast { @[kstack(), retval != 0] = count(); }'\
-c "/bin/sh walktrees /testfs 20"

Best ran more than once.

Expected results after "warmup":
[snip]
@[
    __ext4_iget+275
    ext4_lookup+224
    __lookup_slow+130
    walk_component+219
    link_path_walk.part.0.constprop.0+614
    path_lookupat+62
    filename_lookup+204
    vfs_statx+128
    vfs_fstatat+131
    __do_sys_newfstatat+38
    do_syscall_64+87
    entry_SYSCALL_64_after_hwframe+118
, 1]: 20000
@[
    __ext4_iget+275
    ext4_lookup+224
    __lookup_slow+130
    walk_component+219
    path_lookupat+106
    filename_lookup+204
    vfs_statx+128
    vfs_fstatat+131
    __do_sys_newfstatat+38
    do_syscall_64+87
    entry_SYSCALL_64_after_hwframe+118
, 1]: 20000000

That is 20 million calls for the initial lookup and 20 million after
allocating a new inode, all of them failing to return a value != 0
(i.e., they are returning NULL -- no match found).

Of course aborting the benchmark in the middle and starting it again (or
messing with the state in other ways) is going to alter these results.

Benchmark can be found here: https://people.freebsd.org/~mjg/fstree.tgz

[1] https://lore.kernel.org/all/20231206060629.2827226-1-david@fromorbit.com/

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240611173824.535995-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-12 14:09:59 +02:00
Gabriel Krisman Bertazi
6a79a4e187
libfs: Introduce case-insensitive string comparison helper
generic_ci_match can be used by case-insensitive filesystems to compare
strings under lookup with dirents in a case-insensitive way.  This
function is currently reimplemented by each filesystem supporting
casefolding, so this reduces code duplication in filesystem-specific
code.

[eugen.hristev@collabora.com: rework to first test the exact match, cleanup
and add error message]

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com>
Link: https://lore.kernel.org/r/20240606073353.47130-4-eugen.hristev@collabora.com
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-07 17:00:44 +02:00
Mateusz Guzik
dff60734fc vfs: retire user_path_at_empty and drop empty arg from getname_flags
No users after do_readlinkat started doing the job on its own.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240604155257.109500-3-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-06-05 17:03:57 +02:00
Jeff Layton
3aa63a569c fs: switch timespec64 fields in inode to discrete integers
Adjacent struct timespec64's pack poorly. Switch them to discrete
integer fields for the seconds and nanoseconds. This shaves 8 bytes off
struct inode with a garden-variety Fedora Kconfig on x86_64, but that
also moves the i_lock into the previous cacheline, away from the fields
it protects.

To remedy that, move i_generation above the i_lock, which moves the new
4-byte hole to just after the i_fsnotify_mask in my setup. Amir has
plans to use that to expand the i_fsnotify_mask, so add a comment to
that effect as well.

Cc: Amir Goldstein <amir73il@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240517-amtime-v1-1-7b804ca4be8f@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-05-27 15:58:46 +02:00
Linus Torvalds
b6394d6f71 Assorted commits that had missed the last merge window...
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Merge tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc vfs updates from Al Viro:
 "Assorted commits that had missed the last merge window..."

* tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  remove call_{read,write}_iter() functions
  do_dentry_open(): kill inode argument
  kernel_file_open(): get rid of inode argument
  get_file_rcu(): no need to check for NULL separately
  fd_is_open(): move to fs/file.c
  close_on_exec(): pass files_struct instead of fdtable
2024-05-21 13:11:44 -07:00
Linus Torvalds
119d1b8a5d New code for 6.10:
* Introduce Parent Pointer extended attribute for inodes.
 
   * Online Repair
     - Implement atomic file content exchanges i.e. exchange ranges of bytes
       between two files atomically.
     - Create temporary files to repair file-based metadata. This uses atomic
       file content exchange facility to swap file fork mappings between the
       temporary file and the metadata inode.
 
     - Allow callers of directory/xattr code to set an explicit owner number to
       be written into the header fields of any new blocks that are created.
       This is required to avoid walking every block of the new structure and
       modify their ownership during online repair.
     - Repair
       - Extended attributes
       - Inode unlinked state
       - Directories
       - Symbolic links
       - AGI's unlinked inode list.
       - Parent pointers.
     - Move Orphan files to lost and found directory.
     - Fixes for Inode repair functionality.
     - Introduce a new sub-AG FITRIM implementation to reduce the duration for
       which the AGF lock is held.
     - Updates for the design documentation.
     - Use Parent Pointers to assist in checking directories, parent pointers,
       extended attributes, and link counts.
 
   * Bring back delalloc support for realtime devices which have an extent size
     that is equal to filesystem's block size.
 
   * Improve performance of log incompat feature handling.
 
   * Fixes
     - Prevent userspace from reading invalid file data due to incorrect.
       updation of file size when performing a non-atomic clone operation.
     - Minor fixes to online repair.
     - Fix confusing return values from xfs_bmapi_write().
     - Fix an out of bounds access due to incorrect h_size during log recovery.
     - Defer upgrading the extent counters in xfs_reflink_end_cow_extent() until
       we know we are going to modify the extent mapping.
     - Remove racy access to if_bytes check in xfs_reflink_end_cow_extent().
     - Fix sparse warnings.
 
   * Cleanups
     - Hold inode locks on all files involved in a rename until the completion
       of the operation. This is in preparation for the parent pointers patchset
       where parent pointers are applied in a separate chained update from the
       actual directory update.
     - Compile out v4 support when disabled.
     - Cleanup xfs_extent_busy_clear().
     - Remove unused flags and fields from struct xfs_da_args.
     - Remove definitions of unused functions.
     - Improve extended attribute validation.
     - Add higher level directory operations helpers to remove duplication of
       code.
     - Cleanup quota (un)reservation interfaces.
 
 Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
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Merge tag 'xfs-6.10-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Chandan Babu:
 "Online repair feature continues to be expanded. Also, we now support
  delayed allocation for realtime devices which have an extent size that
  is equal to filesystem's block size.

  New code:

   - Introduce Parent Pointer extended attribute for inodes

   - Bring back delalloc support for realtime devices which have an
     extent size that is equal to filesystem's block size

   - Improve performance of log incompat feature handling

  Online Repair:

   - Implement atomic file content exchanges i.e. exchange ranges of
     bytes between two files atomically

   - Create temporary files to repair file-based metadata. This uses
     atomic file content exchange facility to swap file fork mappings
     between the temporary file and the metadata inode

   - Allow callers of directory/xattr code to set an explicit owner
     number to be written into the header fields of any new blocks that
     are created. This is required to avoid walking every block of the
     new structure and modify their ownership during online repair

   - Repair more data structures:
       - Extended attributes
       - Inode unlinked state
       - Directories
       - Symbolic links
       - AGI's unlinked inode list
       - Parent pointers

   - Move Orphan files to lost and found directory

   - Fixes for Inode repair functionality

   - Introduce a new sub-AG FITRIM implementation to reduce the duration
     for which the AGF lock is held

   - Updates for the design documentation

   - Use Parent Pointers to assist in checking directories, parent
     pointers, extended attributes, and link counts

  Fixes:

   - Prevent userspace from reading invalid file data due to incorrect.
     updation of file size when performing a non-atomic clone operation

   - Minor fixes to online repair

   - Fix confusing return values from xfs_bmapi_write()

   - Fix an out of bounds access due to incorrect h_size during log
     recovery

   - Defer upgrading the extent counters in xfs_reflink_end_cow_extent()
     until we know we are going to modify the extent mapping

   - Remove racy access to if_bytes check in
     xfs_reflink_end_cow_extent()

   - Fix sparse warnings

  Cleanups:

   - Hold inode locks on all files involved in a rename until the
     completion of the operation. This is in preparation for the parent
     pointers patchset where parent pointers are applied in a separate
     chained update from the actual directory update

   - Compile out v4 support when disabled

   - Cleanup xfs_extent_busy_clear()

   - Remove unused flags and fields from struct xfs_da_args

   - Remove definitions of unused functions

   - Improve extended attribute validation

   - Add higher level directory operations helpers to remove duplication
     of code

   - Cleanup quota (un)reservation interfaces"

* tag 'xfs-6.10-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (221 commits)
  xfs: simplify iext overflow checking and upgrade
  xfs: remove a racy if_bytes check in xfs_reflink_end_cow_extent
  xfs: upgrade the extent counters in xfs_reflink_end_cow_extent later
  xfs: xfs_quota_unreserve_blkres can't fail
  xfs: consolidate the xfs_quota_reserve_blkres definitions
  xfs: clean up buffer allocation in xlog_do_recovery_pass
  xfs: fix log recovery buffer allocation for the legacy h_size fixup
  xfs: widen flags argument to the xfs_iflags_* helpers
  xfs: minor cleanups of xfs_attr3_rmt_blocks
  xfs: create a helper to compute the blockcount of a max sized remote value
  xfs: turn XFS_ATTR3_RMT_BUF_SPACE into a function
  xfs: use unsigned ints for non-negative quantities in xfs_attr_remote.c
  xfs: do not allocate the entire delalloc extent in xfs_bmapi_write
  xfs: fix xfs_bmap_add_extent_delay_real for partial conversions
  xfs: remove the xfs_iext_peek_prev_extent call in xfs_bmapi_allocate
  xfs: pass the actual offset and len to allocate to xfs_bmapi_allocate
  xfs: don't open code XFS_FILBLKS_MIN in xfs_bmapi_write
  xfs: lift a xfs_valid_startblock into xfs_bmapi_allocate
  xfs: remove the unusued tmp_logflags variable in xfs_bmapi_allocate
  xfs: fix error returns from xfs_bmapi_write
  ...
2024-05-20 12:55:12 -07:00
Linus Torvalds
5af9d1cf39 \n
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Merge tag 'fsnotify_for_v6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:

 - reduce overhead of fsnotify infrastructure when no permission events
   are in use

 - a few small cleanups

* tag 'fsnotify_for_v6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: fix UAF from FS_ERROR event on a shutting down filesystem
  fsnotify: optimize the case of no permission event watchers
  fsnotify: use an enum for group priority constants
  fsnotify: move s_fsnotify_connectors into fsnotify_sb_info
  fsnotify: lazy attach fsnotify_sb_info state to sb
  fsnotify: create helper fsnotify_update_sb_watchers()
  fsnotify: pass object pointer and type to fsnotify mark helpers
  fanotify: merge two checks regarding add of ignore mark
  fsnotify: create a wrapper fsnotify_find_inode_mark()
  fsnotify: create helpers to get sb and connp from object
  fsnotify: rename fsnotify_{get,put}_sb_connectors()
  fsnotify: Avoid -Wflex-array-member-not-at-end warning
  fanotify: remove unneeded sub-zero check for unsigned value
2024-05-20 12:31:43 -07:00
Linus Torvalds
61307b7be4 The usual shower of singleton fixes and minor series all over MM,
documented (hopefully adequately) in the respective changelogs.  Notable
 series include:
 
 - Lucas Stach has provided some page-mapping
   cleanup/consolidation/maintainability work in the series "mm/treewide:
   Remove pXd_huge() API".
 
 - In the series "Allow migrate on protnone reference with
   MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
   MPOL_PREFERRED_MANY mode, yielding almost doubled performance in one
   test.
 
 - In their series "Memory allocation profiling" Kent Overstreet and
   Suren Baghdasaryan have contributed a means of determining (via
   /proc/allocinfo) whereabouts in the kernel memory is being allocated:
   number of calls and amount of memory.
 
 - Matthew Wilcox has provided the series "Various significant MM
   patches" which does a number of rather unrelated things, but in largely
   similar code sites.
 
 - In his series "mm: page_alloc: freelist migratetype hygiene" Johannes
   Weiner has fixed the page allocator's handling of migratetype requests,
   with resulting improvements in compaction efficiency.
 
 - In the series "make the hugetlb migration strategy consistent" Baolin
   Wang has fixed a hugetlb migration issue, which should improve hugetlb
   allocation reliability.
 
 - Liu Shixin has hit an I/O meltdown caused by readahead in a
   memory-tight memcg.  Addressed in the series "Fix I/O high when memory
   almost met memcg limit".
 
 - In the series "mm/filemap: optimize folio adding and splitting" Kairui
   Song has optimized pagecache insertion, yielding ~10% performance
   improvement in one test.
 
 - Baoquan He has cleaned up and consolidated the early zone
   initialization code in the series "mm/mm_init.c: refactor
   free_area_init_core()".
 
 - Baoquan has also redone some MM initializatio code in the series
   "mm/init: minor clean up and improvement".
 
 - MM helper cleanups from Christoph Hellwig in his series "remove
   follow_pfn".
 
 - More cleanups from Matthew Wilcox in the series "Various page->flags
   cleanups".
 
 - Vlastimil Babka has contributed maintainability improvements in the
   series "memcg_kmem hooks refactoring".
 
 - More folio conversions and cleanups in Matthew Wilcox's series
 
 	"Convert huge_zero_page to huge_zero_folio"
 	"khugepaged folio conversions"
 	"Remove page_idle and page_young wrappers"
 	"Use folio APIs in procfs"
 	"Clean up __folio_put()"
 	"Some cleanups for memory-failure"
 	"Remove page_mapping()"
 	"More folio compat code removal"
 
 - David Hildenbrand chipped in with "fs/proc/task_mmu: convert hugetlb
   functions to work on folis".
 
 - Code consolidation and cleanup work related to GUP's handling of
   hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".
 
 - Rick Edgecombe has developed some fixes to stack guard gaps in the
   series "Cover a guard gap corner case".
 
 - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the series
   "mm/ksm: fix ksm exec support for prctl".
 
 - Baolin Wang has implemented NUMA balancing for multi-size THPs.  This
   is a simple first-cut implementation for now.  The series is "support
   multi-size THP numa balancing".
 
 - Cleanups to vma handling helper functions from Matthew Wilcox in the
   series "Unify vma_address and vma_pgoff_address".
 
 - Some selftests maintenance work from Dev Jain in the series
   "selftests/mm: mremap_test: Optimizations and style fixes".
 
 - Improvements to the swapping of multi-size THPs from Ryan Roberts in
   the series "Swap-out mTHP without splitting".
 
 - Kefeng Wang has significantly optimized the handling of arm64's
   permission page faults in the series
 
 	"arch/mm/fault: accelerate pagefault when badaccess"
 	"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"
 
 - GUP cleanups from David Hildenbrand in "mm/gup: consistently call it
   GUP-fast".
 
 - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault path to
   use struct vm_fault".
 
 - selftests build fixes from John Hubbard in the series "Fix
   selftests/mm build without requiring "make headers"".
 
 - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
   series "Improved Memory Tier Creation for CPUless NUMA Nodes".  Fixes
   the initialization code so that migration between different memory types
   works as intended.
 
 - David Hildenbrand has improved follow_pte() and fixed an errant driver
   in the series "mm: follow_pte() improvements and acrn follow_pte()
   fixes".
 
 - David also did some cleanup work on large folio mapcounts in his
   series "mm: mapcount for large folios + page_mapcount() cleanups".
 
 - Folio conversions in KSM in Alex Shi's series "transfer page to folio
   in KSM".
 
 - Barry Song has added some sysfs stats for monitoring multi-size THP's
   in the series "mm: add per-order mTHP alloc and swpout counters".
 
 - Some zswap cleanups from Yosry Ahmed in the series "zswap same-filled
   and limit checking cleanups".
 
 - Matthew Wilcox has been looking at buffer_head code and found the
   documentation to be lacking.  The series is "Improve buffer head
   documentation".
 
 - Multi-size THPs get more work, this time from Lance Yang.  His series
   "mm/madvise: enhance lazyfreeing with mTHP in madvise_free" optimizes
   the freeing of these things.
 
 - Kemeng Shi has added more userspace-visible writeback instrumentation
   in the series "Improve visibility of writeback".
 
 - Kemeng Shi then sent some maintenance work on top in the series "Fix
   and cleanups to page-writeback".
 
 - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in the
   series "Improve anon_vma scalability for anon VMAs".  Intel's test bot
   reported an improbable 3x improvement in one test.
 
 - SeongJae Park adds some DAMON feature work in the series
 
 	"mm/damon: add a DAMOS filter type for page granularity access recheck"
 	"selftests/damon: add DAMOS quota goal test"
 
 - Also some maintenance work in the series
 
 	"mm/damon/paddr: simplify page level access re-check for pageout"
 	"mm/damon: misc fixes and improvements"
 
 - David Hildenbrand has disabled some known-to-fail selftests ni the
   series "selftests: mm: cow: flag vmsplice() hugetlb tests as XFAIL".
 
 - memcg metadata storage optimizations from Shakeel Butt in "memcg:
   reduce memory consumption by memcg stats".
 
 - DAX fixes and maintenance work from Vishal Verma in the series
   "dax/bus.c: Fixups for dax-bus locking".
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Merge tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull mm updates from Andrew Morton:
 "The usual shower of singleton fixes and minor series all over MM,
  documented (hopefully adequately) in the respective changelogs.
  Notable series include:

   - Lucas Stach has provided some page-mapping cleanup/consolidation/
     maintainability work in the series "mm/treewide: Remove pXd_huge()
     API".

   - In the series "Allow migrate on protnone reference with
     MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
     MPOL_PREFERRED_MANY mode, yielding almost doubled performance in
     one test.

   - In their series "Memory allocation profiling" Kent Overstreet and
     Suren Baghdasaryan have contributed a means of determining (via
     /proc/allocinfo) whereabouts in the kernel memory is being
     allocated: number of calls and amount of memory.

   - Matthew Wilcox has provided the series "Various significant MM
     patches" which does a number of rather unrelated things, but in
     largely similar code sites.

   - In his series "mm: page_alloc: freelist migratetype hygiene"
     Johannes Weiner has fixed the page allocator's handling of
     migratetype requests, with resulting improvements in compaction
     efficiency.

   - In the series "make the hugetlb migration strategy consistent"
     Baolin Wang has fixed a hugetlb migration issue, which should
     improve hugetlb allocation reliability.

   - Liu Shixin has hit an I/O meltdown caused by readahead in a
     memory-tight memcg. Addressed in the series "Fix I/O high when
     memory almost met memcg limit".

   - In the series "mm/filemap: optimize folio adding and splitting"
     Kairui Song has optimized pagecache insertion, yielding ~10%
     performance improvement in one test.

   - Baoquan He has cleaned up and consolidated the early zone
     initialization code in the series "mm/mm_init.c: refactor
     free_area_init_core()".

   - Baoquan has also redone some MM initializatio code in the series
     "mm/init: minor clean up and improvement".

   - MM helper cleanups from Christoph Hellwig in his series "remove
     follow_pfn".

   - More cleanups from Matthew Wilcox in the series "Various
     page->flags cleanups".

   - Vlastimil Babka has contributed maintainability improvements in the
     series "memcg_kmem hooks refactoring".

   - More folio conversions and cleanups in Matthew Wilcox's series:
	"Convert huge_zero_page to huge_zero_folio"
	"khugepaged folio conversions"
	"Remove page_idle and page_young wrappers"
	"Use folio APIs in procfs"
	"Clean up __folio_put()"
	"Some cleanups for memory-failure"
	"Remove page_mapping()"
	"More folio compat code removal"

   - David Hildenbrand chipped in with "fs/proc/task_mmu: convert
     hugetlb functions to work on folis".

   - Code consolidation and cleanup work related to GUP's handling of
     hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".

   - Rick Edgecombe has developed some fixes to stack guard gaps in the
     series "Cover a guard gap corner case".

   - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the
     series "mm/ksm: fix ksm exec support for prctl".

   - Baolin Wang has implemented NUMA balancing for multi-size THPs.
     This is a simple first-cut implementation for now. The series is
     "support multi-size THP numa balancing".

   - Cleanups to vma handling helper functions from Matthew Wilcox in
     the series "Unify vma_address and vma_pgoff_address".

   - Some selftests maintenance work from Dev Jain in the series
     "selftests/mm: mremap_test: Optimizations and style fixes".

   - Improvements to the swapping of multi-size THPs from Ryan Roberts
     in the series "Swap-out mTHP without splitting".

   - Kefeng Wang has significantly optimized the handling of arm64's
     permission page faults in the series
	"arch/mm/fault: accelerate pagefault when badaccess"
	"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"

   - GUP cleanups from David Hildenbrand in "mm/gup: consistently call
     it GUP-fast".

   - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault
     path to use struct vm_fault".

   - selftests build fixes from John Hubbard in the series "Fix
     selftests/mm build without requiring "make headers"".

   - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
     series "Improved Memory Tier Creation for CPUless NUMA Nodes".
     Fixes the initialization code so that migration between different
     memory types works as intended.

   - David Hildenbrand has improved follow_pte() and fixed an errant
     driver in the series "mm: follow_pte() improvements and acrn
     follow_pte() fixes".

   - David also did some cleanup work on large folio mapcounts in his
     series "mm: mapcount for large folios + page_mapcount() cleanups".

   - Folio conversions in KSM in Alex Shi's series "transfer page to
     folio in KSM".

   - Barry Song has added some sysfs stats for monitoring multi-size
     THP's in the series "mm: add per-order mTHP alloc and swpout
     counters".

   - Some zswap cleanups from Yosry Ahmed in the series "zswap
     same-filled and limit checking cleanups".

   - Matthew Wilcox has been looking at buffer_head code and found the
     documentation to be lacking. The series is "Improve buffer head
     documentation".

   - Multi-size THPs get more work, this time from Lance Yang. His
     series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free"
     optimizes the freeing of these things.

   - Kemeng Shi has added more userspace-visible writeback
     instrumentation in the series "Improve visibility of writeback".

   - Kemeng Shi then sent some maintenance work on top in the series
     "Fix and cleanups to page-writeback".

   - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in
     the series "Improve anon_vma scalability for anon VMAs". Intel's
     test bot reported an improbable 3x improvement in one test.

   - SeongJae Park adds some DAMON feature work in the series
	"mm/damon: add a DAMOS filter type for page granularity access recheck"
	"selftests/damon: add DAMOS quota goal test"

   - Also some maintenance work in the series
	"mm/damon/paddr: simplify page level access re-check for pageout"
	"mm/damon: misc fixes and improvements"

   - David Hildenbrand has disabled some known-to-fail selftests ni the
     series "selftests: mm: cow: flag vmsplice() hugetlb tests as
     XFAIL".

   - memcg metadata storage optimizations from Shakeel Butt in "memcg:
     reduce memory consumption by memcg stats".

   - DAX fixes and maintenance work from Vishal Verma in the series
     "dax/bus.c: Fixups for dax-bus locking""

* tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits)
  memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order
  selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime
  mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp
  mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault
  selftests: cgroup: add tests to verify the zswap writeback path
  mm: memcg: make alloc_mem_cgroup_per_node_info() return bool
  mm/damon/core: fix return value from damos_wmark_metric_value
  mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
  selftests: cgroup: remove redundant enabling of memory controller
  Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree
  Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT
  Docs/mm/damon/design: use a list for supported filters
  Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command
  Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file
  selftests/damon: classify tests for functionalities and regressions
  selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None'
  selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts
  selftests/damon/_damon_sysfs: check errors from nr_schemes file reads
  mm/damon/core: initialize ->esz_bp from damos_quota_init_priv()
  selftests/damon: add a test for DAMOS quota goal
  ...
2024-05-19 09:21:03 -07:00
Linus Torvalds
353ad6c083 integrity-v6.10
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Merge tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:
 "Two IMA changes, one EVM change, a use after free bug fix, and a code
  cleanup to address "-Wflex-array-member-not-at-end" warnings:

   - The existing IMA {ascii, binary}_runtime_measurements lists include
     a hard coded SHA1 hash. To address this limitation, define per TPM
     enabled hash algorithm {ascii, binary}_runtime_measurements lists

   - Close an IMA integrity init_module syscall measurement gap by
     defining a new critical-data record

   - Enable (partial) EVM support on stacked filesystems (overlayfs).
     Only EVM portable & immutable file signatures are copied up, since
     they do not contain filesystem specific metadata"

* tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: add crypto agility support for template-hash algorithm
  evm: Rename is_unsupported_fs to is_unsupported_hmac_fs
  fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED
  evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509
  ima: re-evaluate file integrity on file metadata change
  evm: Store and detect metadata inode attributes changes
  ima: Move file-change detection variables into new structure
  evm: Use the metadata inode to calculate metadata hash
  evm: Implement per signature type decision in security_inode_copy_up_xattr
  security: allow finer granularity in permitting copy-up of security xattrs
  ima: Rename backing_inode to real_inode
  integrity: Avoid -Wflex-array-member-not-at-end warnings
  ima: define an init_module critical data record
  ima: Fix use-after-free on a dentry's dname.name
2024-05-15 08:43:02 -07:00
Linus Torvalds
1b0aabcc9a vfs-6.10.misc
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Merge tag 'vfs-6.10.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Free up FMODE_* bits. I've freed up bits 6, 7, 8, and 24. That
     means we now have six free FMODE_* bits in total (but bit #6
     already got used for FMODE_WRITE_RESTRICTED)

   - Add FOP_HUGE_PAGES flag (follow-up to FMODE_* cleanup)

   - Add fd_raw cleanup class so we can make use of automatic cleanup
     provided by CLASS(fd_raw, f)(fd) for O_PATH fds as well

   - Optimize seq_puts()

   - Simplify __seq_puts()

   - Add new anon_inode_getfile_fmode() api to allow specifying f_mode
     instead of open-coding it in multiple places

   - Annotate struct file_handle with __counted_by() and use
     struct_size()

   - Warn in get_file() whether f_count resurrection from zero is
     attempted (epoll/drm discussion)

   - Folio-sophize aio

   - Export the subvolume id in statx() for both btrfs and bcachefs

   - Relax linkat(AT_EMPTY_PATH) requirements

   - Add F_DUPFD_QUERY fcntl() allowing to compare two file descriptors
     for dup*() equality replacing kcmp()

  Cleanups:

   - Compile out swapfile inode checks when swap isn't enabled

   - Use (1 << n) notation for FMODE_* bitshifts for clarity

   - Remove redundant variable assignment in fs/direct-io

   - Cleanup uses of strncpy in orangefs

   - Speed up and cleanup writeback

   - Move fsparam_string_empty() helper into header since it's currently
     open-coded in multiple places

   - Add kernel-doc comments to proc_create_net_data_write()

   - Don't needlessly read dentry->d_flags twice

  Fixes:

   - Fix out-of-range warning in nilfs2

   - Fix ecryptfs overflow due to wrong encryption packet size
     calculation

   - Fix overly long line in xfs file_operations (follow-up to FMODE_*
     cleanup)

   - Don't raise FOP_BUFFER_{R,W}ASYNC for directories in xfs (follow-up
     to FMODE_* cleanup)

   - Don't call xfs_file_open from xfs_dir_open (follow-up to FMODE_*
     cleanup)

   - Fix stable offset api to prevent endless loops

   - Fix afs file server rotations

   - Prevent xattr node from overflowing the eraseblock in jffs2

   - Move fdinfo PTRACE_MODE_READ procfs check into the .permission()
     operation instead of .open() operation since this caused userspace
     regressions"

* tag 'vfs-6.10.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits)
  afs: Fix fileserver rotation getting stuck
  selftests: add F_DUPDFD_QUERY selftests
  fcntl: add F_DUPFD_QUERY fcntl()
  file: add fd_raw cleanup class
  fs: WARN when f_count resurrection is attempted
  seq_file: Simplify __seq_puts()
  seq_file: Optimize seq_puts()
  proc: Move fdinfo PTRACE_MODE_READ check into the inode .permission operation
  fs: Create anon_inode_getfile_fmode()
  xfs: don't call xfs_file_open from xfs_dir_open
  xfs: drop fop_flags for directories
  xfs: fix overly long line in the file_operations
  shmem: Fix shmem_rename2()
  libfs: Add simple_offset_rename() API
  libfs: Fix simple_offset_rename_exchange()
  jffs2: prevent xattr node from overflowing the eraseblock
  vfs, swap: compile out IS_SWAPFILE() on swapless configs
  vfs: relax linkat() AT_EMPTY_PATH - aka flink() - requirements
  fs/direct-io: remove redundant assignment to variable retval
  fs/dcache: Re-use value stored to dentry->d_flags instead of re-reading
  ...
2024-05-13 11:40:06 -07:00
Kees Cook
f6bdc7865e
fs: WARN when f_count resurrection is attempted
It should never happen that get_file() is called on a file with
f_count equal to zero. If this happens, a use-after-free condition
has happened[1], and we need to attempt a best-effort reporting of
the situation to help find the root cause more easily. Additionally,
this serves as a data corruption indicator that system owners using
warn_limit or panic_on_warn would like to have detected.

Link: https://lore.kernel.org/lkml/7c41cf3c-2a71-4dbb-8f34-0337890906fc@gmail.com/ [1]
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240503201620.work.651-kees@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-05-04 11:42:01 +02:00
Kent Overstreet
a5674119f0 fs: convert alloc_inode_sb() to a macro
We're introducing alloc tagging, which tracks memory allocations by
callsite.  Converting alloc_inode_sb() to a macro means allocations will
be tracked by its caller, which is a bit more useful.

Link: https://lkml.kernel.org/r/20240321163705.3067592-6-surenb@google.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:55:50 -07:00
Christian Brauner
193feb69af
Merge patch series 'Fix shmem_rename2 directory offset calculation' of https://lore.kernel.org/r/20240415152057.4605-1-cel@kernel.org
Pull shmem_rename2() offset fixes from Chuck Lever:

The existing code in shmem_rename2() allocates a fresh directory
offset value when renaming over an existing destination entry. User
space does not expect this behavior. In particular, applications
that rename while walking a directory can loop indefinitely because
they never reach the end of the directory.

* 'Fix shmem_rename2 directory offset calculation' of https://lore.kernel.org/r/20240415152057.4605-1-cel@kernel.org: (3 commits)
  shmem: Fix shmem_rename2()
  libfs: Add simple_offset_rename() API
  libfs: Fix simple_offset_rename_exchange()

 fs/libfs.c         | 55 +++++++++++++++++++++++++++++++++++++++++-----
 include/linux/fs.h |  2 ++
 mm/shmem.c         |  3 +--
 3 files changed, 52 insertions(+), 8 deletions(-)

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-17 13:49:56 +02:00
Chuck Lever
5a1a25be99
libfs: Add simple_offset_rename() API
I'm about to fix a tmpfs rename bug that requires the use of
internal simple_offset helpers that are not available in mm/shmem.c

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20240415152057.4605-3-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-17 13:49:43 +02:00
Darrick J. Wong
5b9932f600 vfs: export remap and write check helpers
Export these functions so that the next patch can use them to check the
file ranges being passed to the XFS_IOC_EXCHANGE_RANGE operation.

Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-04-15 14:54:13 -07:00
Miklos Szeredi
7c98f7cb8f remove call_{read,write}_iter() functions
These have no clear purpose.  This is effectively a revert of commit
bb7462b6fd ("vfs: use helpers for calling f_op->{read,write}_iter()").

The patch was created with the help of a coccinelle script.

Fixes: bb7462b6fd ("vfs: use helpers for calling f_op->{read,write}_iter()")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-04-15 16:03:25 -04:00
Al Viro
af58dc1f50 kernel_file_open(): get rid of inode argument
always equal to ->dentry->d_inode of the path argument these
days.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-04-15 16:03:24 -04:00
Alexey Dobriyan
e964fc7757
vfs, swap: compile out IS_SWAPFILE() on swapless configs
No swap support -- no swapfiles possible.

Signed-off-by: Alexey Dobriyan (Yandex) <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/2391c7f5-0f83-4188-ae56-4ec7ccbf2576@p183
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-15 16:56:14 +02:00
Stefan Berger
1f65e57dc5 fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED
Now that EVM supports RSA signatures for previously completely
unsupported filesystems rename the flag SB_I_EVM_UNSUPPORTED to
SB_I_EVM_HMAC_UNSUPPORTED to reflect that only HMAC is not supported.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Acked-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2024-04-09 17:14:58 -04:00
Matthew Wilcox (Oracle)
886b94d25a
fs: Add FOP_HUGE_PAGES
Instead of checking for specific file_operations, add a bit to
file_operations which denotes a file that only contain hugetlb pages.
This lets us make hugetlbfs_file_operations static, and removes
is_file_shm_hugepages() completely.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240407201122.3783877-1-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-09 10:53:44 +02:00
Christian Brauner
0a4f544d83
fs: use bit shifts for FMODE_* flags
Make it easier to see what bits are still available.

Link: https://lore.kernel.org/r/20240406061604.GA538574@ZenIV
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-07 18:04:46 +02:00
Christian Brauner
210a03c9d5
fs: claw back a few FMODE_* bits
There's a bunch of flags that are purely based on what the file
operations support while also never being conditionally set or unset.
IOW, they're not subject to change for individual files. Imho, such
flags don't need to live in f_mode they might as well live in the fops
structs itself. And the fops struct already has that lonely
mmap_supported_flags member. We might as well turn that into a generic
fop_flags member and move a few flags from FMODE_* space into FOP_*
space. That gets us four FMODE_* bits back and the ability for new
static flags that are about file ops to not have to live in FMODE_*
space but in their own FOP_* space. It's not the most beautiful thing
ever but it gets the job done. Yes, there'll be an additional pointer
chase but hopefully that won't matter for these flags.

I suspect there's a few more we can move into there and that we can also
redirect a bunch of new flag suggestions that follow this pattern into
the fop_flags field instead of f_mode.

Link: https://lore.kernel.org/r/20240328-gewendet-spargel-aa60a030ef74@brauner
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-07 13:49:02 +02:00
Gustavo A. R. Silva
68d6f4f3fb
fs: Annotate struct file_handle with __counted_by() and use struct_size()
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

While there, use struct_size() helper, instead of the open-coded
version.

[brauner@kernel.org: contains a fix by Edward for an OOB access]
Reported-by: syzbot+4139435cb1b34cf759c2@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Link: https://lore.kernel.org/r/tencent_A7845DD769577306D813742365E976E3A205@qq.com
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/ZgImCXTdGDTeBvSS@neat
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-04-05 15:53:47 +02:00
Amir Goldstein
cb5d4f48c1 fsnotify: move s_fsnotify_connectors into fsnotify_sb_info
Move the s_fsnotify_connectors counter into the per-sb fsnotify state.

Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240317184154.1200192-9-amir73il@gmail.com>
2024-04-04 16:24:16 +02:00
Amir Goldstein
07a3b8d0bf fsnotify: lazy attach fsnotify_sb_info state to sb
Define a container struct fsnotify_sb_info to hold per-sb state,
including the reference to sb marks connector.

Allocate the fsnotify_sb_info state before attaching connector to any
object on the sb and free it only when killing sb.

This state is going to be used for storing per priority watched objects
counters.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240317184154.1200192-8-amir73il@gmail.com>
2024-04-04 16:24:16 +02:00
Christian Brauner
ddd65e19c6
block: handle BLK_OPEN_RESTRICT_WRITES correctly
Last kernel release we introduce CONFIG_BLK_DEV_WRITE_MOUNTED. By
default this option is set. When it is set the long-standing behavior
of being able to write to mounted block devices is enabled.

But in order to guard against unintended corruption by writing to the
block device buffer cache CONFIG_BLK_DEV_WRITE_MOUNTED can be turned
off. In that case it isn't possible to write to mounted block devices
anymore.

A filesystem may open its block devices with BLK_OPEN_RESTRICT_WRITES
which disallows concurrent BLK_OPEN_WRITE access. When we still had the
bdev handle around we could recognize BLK_OPEN_RESTRICT_WRITES because
the mode was passed around. Since we managed to get rid of the bdev
handle we changed that logic to recognize BLK_OPEN_RESTRICT_WRITES based
on whether the file was opened writable and writes to that block device
are blocked. That logic doesn't work because we do allow
BLK_OPEN_RESTRICT_WRITES to be specified without BLK_OPEN_WRITE.

Fix the detection logic and use an FMODE_* bit. We could've also abused
O_EXCL as an indicator that BLK_OPEN_RESTRICT_WRITES has been requested.
For userspace open paths O_EXCL will never be retained but for internal
opens where we open files that are never installed into a file
descriptor table this is fine. But it would be a gamble that this
doesn't cause bugs. Note that BLK_OPEN_RESTRICT_WRITES is an internal
only flag that cannot directly be raised by userspace. It is implicitly
raised during mounting.

Passes xftests and blktests with CONFIG_BLK_DEV_WRITE_MOUNTED set and
unset.

Link: https://lore.kernel.org/r/ZfyyEwu9Uq5Pgb94@casper.infradead.org
Link: https://lore.kernel.org/r/20240323-zielbereich-mittragen-6fdf14876c3e@brauner
Fixes: 321de651fa ("block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access")
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-27 09:31:41 +01:00
Linus Torvalds
32a50540c3 bcachefs updates for 6.9
- Subvolume children btree; this is needed for providing a userspace
    interface for walking subvolumes, which will come later
  - Lots of improvements to directory structure checking
  - Improved journal pipelining, significantly improving performance on
    high iodepth write workloads
  - Discard path improvements: the discard path is more efficient, and no
    longer flushes the journal unnecessarily
  - Buffered write path can now avoid taking the inode lock
  - new mm helper: memalloc_flags_{save|restore}
  - mempool now does kvmalloc mempools
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Merge tag 'bcachefs-2024-03-13' of https://evilpiepirate.org/git/bcachefs

Pull bcachefs updates from Kent Overstreet:

 - Subvolume children btree; this is needed for providing a userspace
   interface for walking subvolumes, which will come later

 - Lots of improvements to directory structure checking

 - Improved journal pipelining, significantly improving performance on
   high iodepth write workloads

 - Discard path improvements: the discard path is more efficient, and no
   longer flushes the journal unnecessarily

 - Buffered write path can now avoid taking the inode lock

 - new mm helper: memalloc_flags_{save|restore}

 - mempool now does kvmalloc mempools

* tag 'bcachefs-2024-03-13' of https://evilpiepirate.org/git/bcachefs: (128 commits)
  bcachefs: time_stats: shrink time_stat_buffer for better alignment
  bcachefs: time_stats: split stats-with-quantiles into a separate structure
  bcachefs: mean_and_variance: put struct mean_and_variance_weighted on a diet
  bcachefs: time_stats: add larger units
  bcachefs: pull out time_stats.[ch]
  bcachefs: reconstruct_alloc cleanup
  bcachefs: fix bch_folio_sector padding
  bcachefs: Fix btree key cache coherency during replay
  bcachefs: Always flush write buffer in delete_dead_inodes()
  bcachefs: Fix order of gc_done passes
  bcachefs: fix deletion of indirect extents in btree_gc
  bcachefs: Prefer struct_size over open coded arithmetic
  bcachefs: Kill unused flags argument to btree_split()
  bcachefs: Check for writing superblocks with nonsense member seq fields
  bcachefs: fix bch2_journal_buf_to_text()
  lib/generic-radix-tree.c: Make nodes more reasonably sized
  bcachefs: copy_(to|from)_user_errcode()
  bcachefs: Split out bkey_types.h
  bcachefs: fix lost journal buf wakeup due to improved pipelining
  bcachefs: intercept mountoption value for bool type
  ...
2024-03-15 09:00:09 -07:00
Kent Overstreet
66a67c860c fs: file_remove_privs_flags()
Rename and export __file_remove_privs(); for a buffered write path that
doesn't take the inode lock we need to be able to check if the operation
needs to do work first.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
2024-03-13 21:22:25 -04:00
Linus Torvalds
e5e038b7ae \n
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Merge tag 'fs_for_v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull ext2, isofs, udf, and quota updates from Jan Kara:
 "A lot of material this time:

   - removal of a lot of GFP_NOFS usage from ext2, udf, quota (either it
     was legacy or replaced with scoped memalloc_nofs_*() API)

   - removal of BUG_ONs in quota code

   - conversion of UDF to the new mount API

   - tightening quota on disk format verification

   - fix some potentially unsafe use of RCU pointers in quota code and
     annotate everything properly to make sparse happy

   - a few other small quota, ext2, udf, and isofs fixes"

* tag 'fs_for_v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (26 commits)
  udf: remove SLAB_MEM_SPREAD flag usage
  quota: remove SLAB_MEM_SPREAD flag usage
  isofs: remove SLAB_MEM_SPREAD flag usage
  ext2: remove SLAB_MEM_SPREAD flag usage
  ext2: mark as deprecated
  udf: convert to new mount API
  udf: convert novrs to an option flag
  MAINTAINERS: add missing git address for ext2 entry
  quota: Detect loops in quota tree
  quota: Properly annotate i_dquot arrays with __rcu
  quota: Fix rcu annotations of inode dquot pointers
  isofs: handle CDs with bad root inode but good Joliet root directory
  udf: Avoid invalid LVID used on mount
  quota: Fix potential NULL pointer dereference
  quota: Drop GFP_NOFS instances under dquot->dq_lock and dqio_sem
  quota: Set nofs allocation context when acquiring dqio_sem
  ext2: Remove GFP_NOFS use in ext2_xattr_cache_insert()
  ext2: Drop GFP_NOFS use in ext2_get_blocks()
  ext2: Drop GFP_NOFS allocation from ext2_init_block_alloc_info()
  udf: Remove GFP_NOFS allocation in udf_expand_file_adinicb()
  ...
2024-03-13 14:30:58 -07:00
Linus Torvalds
0f1a876682 vfs-6.9.uuid
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Merge tag 'vfs-6.9.uuid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs uuid updates from Christian Brauner:
 "This adds two new ioctl()s for getting the filesystem uuid and
  retrieving the sysfs path based on the path of a mounted filesystem.
  Getting the filesystem uuid has been implemented in filesystem
  specific code for a while it's now lifted as a generic ioctl"

* tag 'vfs-6.9.uuid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  xfs: add support for FS_IOC_GETFSSYSFSPATH
  fs: add FS_IOC_GETFSSYSFSPATH
  fat: Hook up sb->s_uuid
  fs: FS_IOC_GETUUID
  ovl: convert to super_set_uuid()
  fs: super_set_uuid()
2024-03-11 11:02:06 -07:00
Linus Torvalds
910202f00a vfs-6.9.super
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Merge tag 'vfs-6.9.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull block handle updates from Christian Brauner:
 "Last cycle we changed opening of block devices, and opening a block
  device would return a bdev_handle. This allowed us to implement
  support for restricting and forbidding writes to mounted block
  devices. It was accompanied by converting and adding helpers to
  operate on bdev_handles instead of plain block devices.

  That was already a good step forward but ultimately it isn't necessary
  to have special purpose helpers for opening block devices internally
  that return a bdev_handle.

  Fundamentally, opening a block device internally should just be
  equivalent to opening files. So now all internal opens of block
  devices return files just as a userspace open would. Instead of
  introducing a separate indirection into bdev_open_by_*() via struct
  bdev_handle bdev_file_open_by_*() is made to just return a struct
  file. Opening and closing a block device just becomes equivalent to
  opening and closing a file.

  This all works well because internally we already have a pseudo fs for
  block devices and so opening block devices is simple. There's a few
  places where we needed to be careful such as during boot when the
  kernel is supposed to mount the rootfs directly without init doing it.
  Here we need to take care to ensure that we flush out any asynchronous
  file close. That's what we already do for opening, unpacking, and
  closing the initramfs. So nothing new here.

  The equivalence of opening and closing block devices to regular files
  is a win in and of itself. But it also has various other advantages.
  We can remove struct bdev_handle completely. Various low-level helpers
  are now private to the block layer. Other helpers were simply
  removable completely.

  A follow-up series that is already reviewed build on this and makes it
  possible to remove bdev->bd_inode and allows various clean ups of the
  buffer head code as well. All places where we stashed a bdev_handle
  now just stash a file and use simple accessors to get to the actual
  block device which was already the case for bdev_handle"

* tag 'vfs-6.9.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
  block: remove bdev_handle completely
  block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access
  bdev: remove bdev pointer from struct bdev_handle
  bdev: make struct bdev_handle private to the block layer
  bdev: make bdev_{release, open_by_dev}() private to block layer
  bdev: remove bdev_open_by_path()
  reiserfs: port block device access to file
  ocfs2: port block device access to file
  nfs: port block device access to files
  jfs: port block device access to file
  f2fs: port block device access to files
  ext4: port block device access to file
  erofs: port device access to file
  btrfs: port device access to file
  bcachefs: port block device access to file
  target: port block device access to file
  s390: port block device access to file
  nvme: port block device access to file
  block2mtd: port device access to files
  bcache: port block device access to files
  ...
2024-03-11 10:52:34 -07:00
Linus Torvalds
0c750012e8 vfs-6.9.file
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Merge tag 'vfs-6.9.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull file locking updates from Christian Brauner:
 "A few years ago struct file_lock_context was added to allow for
  separate lists to track different types of file locks instead of using
  a singly-linked list for all of them.

  Now leases no longer need to be tracked using struct file_lock.
  However, a lot of the infrastructure is identical for leases and locks
  so separating them isn't trivial.

  This splits a group of fields used by both file locks and leases into
  a new struct file_lock_core. The new core struct is embedded in struct
  file_lock. Coccinelle was used to convert a lot of the callers to deal
  with the move, with the remaining 25% or so converted by hand.

  Afterwards several internal functions in fs/locks.c are made to work
  with struct file_lock_core. Ultimately this allows to split struct
  file_lock into struct file_lock and struct file_lease. The file lease
  APIs are then converted to take struct file_lease"

* tag 'vfs-6.9.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (51 commits)
  filelock: fix deadlock detection in POSIX locking
  filelock: always define for_each_file_lock()
  smb: remove redundant check
  filelock: don't do security checks on nfsd setlease calls
  filelock: split leases out of struct file_lock
  filelock: remove temporary compatibility macros
  smb/server: adapt to breakup of struct file_lock
  smb/client: adapt to breakup of struct file_lock
  ocfs2: adapt to breakup of struct file_lock
  nfsd: adapt to breakup of struct file_lock
  nfs: adapt to breakup of struct file_lock
  lockd: adapt to breakup of struct file_lock
  fuse: adapt to breakup of struct file_lock
  gfs2: adapt to breakup of struct file_lock
  dlm: adapt to breakup of struct file_lock
  ceph: adapt to breakup of struct file_lock
  afs: adapt to breakup of struct file_lock
  9p: adapt to breakup of struct file_lock
  filelock: convert seqfile handling to use file_lock_core
  filelock: convert locks_translate_pid to take file_lock_core
  ...
2024-03-11 10:37:45 -07:00
Linus Torvalds
54126fafea vfs-6.9.iomap
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Merge tag 'vfs-6.9.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull iomap updates from Christian Brauner:

 - Restore read-write hints in struct bio through the bi_write_hint
   member for the sake of UFS devices in mobile applications. This can
   result in up to 40% lower write amplification in UFS devices. The
   patch series that builds on this will be coming in via the SCSI
   maintainers (Bart)

 - Overhaul the iomap writeback code. Afterwards ->map_blocks() is able
   to map multiple blocks at once as long as they're in the same folio.
   This reduces CPU usage for buffered write workloads on e.g., xfs on
   systems with lots of cores (Christoph)

 - Record processed bytes in iomap_iter() trace event (Kassey)

 - Extend iomap_writepage_map() trace event after Christoph's
   ->map_block() changes to map mutliple blocks at once (Zhang)

* tag 'vfs-6.9.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (22 commits)
  iomap: Add processed for iomap_iter
  iomap: add pos and dirty_len into trace_iomap_writepage_map
  block, fs: Restore the per-bio/request data lifetime fields
  fs: Propagate write hints to the struct block_device inode
  fs: Move enum rw_hint into a new header file
  fs: Split fcntl_rw_hint()
  fs: Verify write lifetime constants at compile time
  fs: Fix rw_hint validation
  iomap: pass the length of the dirty region to ->map_blocks
  iomap: map multiple blocks at a time
  iomap: submit ioends immediately
  iomap: factor out a iomap_writepage_map_block helper
  iomap: only call mapping_set_error once for each failed bio
  iomap: don't chain bios
  iomap: move the iomap_sector sector calculation out of iomap_add_to_ioend
  iomap: clean up the iomap_alloc_ioend calling convention
  iomap: move all remaining per-folio logic into iomap_writepage_map
  iomap: factor out a iomap_writepage_handle_eof helper
  iomap: move the PF_MEMALLOC check to iomap_writepages
  iomap: move the io_folios field out of struct iomap_ioend
  ...
2024-03-11 10:07:03 -07:00
Linus Torvalds
7ea65c89d8 vfs-6.9.misc
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Merge tag 'vfs-6.9.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "Misc features, cleanups, and fixes for vfs and individual filesystems.

  Features:

   - Support idmapped mounts for hugetlbfs.

   - Add RWF_NOAPPEND flag for pwritev2(). This allows us to fix a bug
     where the passed offset is ignored if the file is O_APPEND. The new
     flag allows a caller to enforce that the offset is honored to
     conform to posix even if the file was opened in append mode.

   - Move i_mmap_rwsem in struct address_space to avoid false sharing
     between i_mmap and i_mmap_rwsem.

   - Convert efs, qnx4, and coda to use the new mount api.

   - Add a generic is_dot_dotdot() helper that's used by various
     filesystems and the VFS code instead of open-coding it multiple
     times.

   - Recently we've added stable offsets which allows stable ordering
     when iterating directories exported through NFS on e.g., tmpfs
     filesystems. Originally an xarray was used for the offset map but
     that caused slab fragmentation issues over time. This switches the
     offset map to the maple tree which has a dense mode that handles
     this scenario a lot better. Includes tests.

   - Finally merge the case-insensitive improvement series Gabriel has
     been working on for a long time. This cleanly propagates case
     insensitive operations through ->s_d_op which in turn allows us to
     remove the quite ugly generic_set_encrypted_ci_d_ops() operations.
     It also improves performance by trying a case-sensitive comparison
     first and then fallback to case-insensitive lookup if that fails.
     This also fixes a bug where overlayfs would be able to be mounted
     over a case insensitive directory which would lead to all sort of
     odd behaviors.

  Cleanups:

   - Make file_dentry() a simple accessor now that ->d_real() is
     simplified because of the backing file work we did the last two
     cycles.

   - Use the dedicated file_mnt_idmap helper in ntfs3.

   - Use smp_load_acquire/store_release() in the i_size_read/write
     helpers and thus remove the hack to handle i_size reads in the
     filemap code.

   - The SLAB_MEM_SPREAD is a nop now. Remove it from various places in
     fs/

   - It's no longer necessary to perform a second built-in initramfs
     unpack call because we retain the contents of the previous
     extraction. Remove it.

   - Now that we have removed various allocators kfree_rcu() always
     works with kmem caches and kmalloc(). So simplify various places
     that only use an rcu callback in order to handle the kmem cache
     case.

   - Convert the pipe code to use a lockdep comparison function instead
     of open-coding the nesting making lockdep validation easier.

   - Move code into fs-writeback.c that was located in a header but can
     be made static as it's only used in that one file.

   - Rewrite the alignment checking iterators for iovec and bvec to be
     easier to read, and also significantly more compact in terms of
     generated code. This saves 270 bytes of text on x86-64 (with
     clang-18) and 224 bytes on arm64 (with gcc-13). In profiles it also
     saves a bit of time for the same workload.

   - Switch various places to use KMEM_CACHE instead of
     kmem_cache_create().

   - Use inode_set_ctime_to_ts() in inode_set_ctime_current()

   - Use kzalloc() in name_to_handle_at() to avoid kernel infoleak.

   - Various smaller cleanups for eventfds.

  Fixes:

   - Fix various comments and typos, and unneeded initializations.

   - Fix stack allocation hack for clang in the select code.

   - Improve dump_mapping() debug code on a best-effort basis.

   - Fix build errors in various selftests.

   - Avoid wrap-around instrumentation in various places.

   - Don't allow user namespaces without an idmapping to be used for
     idmapped mounts.

   - Fix sysv sb_read() call.

   - Fix fallback implementation of the get_name() export operation"

* tag 'vfs-6.9.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (70 commits)
  hugetlbfs: support idmapped mounts
  qnx4: convert qnx4 to use the new mount api
  fs: use inode_set_ctime_to_ts to set inode ctime to current time
  libfs: Drop generic_set_encrypted_ci_d_ops
  ubifs: Configure dentry operations at dentry-creation time
  f2fs: Configure dentry operations at dentry-creation time
  ext4: Configure dentry operations at dentry-creation time
  libfs: Add helper to choose dentry operations at mount-time
  libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
  fscrypt: Drop d_revalidate once the key is added
  fscrypt: Drop d_revalidate for valid dentries during lookup
  fscrypt: Factor out a helper to configure the lookup dentry
  ovl: Always reject mounting over case-insensitive directories
  libfs: Attempt exact-match comparison first during casefolded lookup
  efs: remove SLAB_MEM_SPREAD flag usage
  jfs: remove SLAB_MEM_SPREAD flag usage
  minix: remove SLAB_MEM_SPREAD flag usage
  openpromfs: remove SLAB_MEM_SPREAD flag usage
  proc: remove SLAB_MEM_SPREAD flag usage
  qnx6: remove SLAB_MEM_SPREAD flag usage
  ...
2024-03-11 09:38:17 -07:00
Christian Brauner
09406ad8e5 case-insensitive updates for 6.9
- Patch case-insensitive lookup by trying the case-exact comparison
 first, before falling back to costly utf8 casefolded comparison.
 
 - Fix to forbid using a case-insensitive directory as part of an
 overlayfs mount.
 
 - Patchset to ensure d_op are set at d_alloc time for fscrypt and
 casefold volumes, ensuring filesystem dentries will all have the correct
 ops, whether they come from a lookup or not.
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Merge tag 'for-next-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/krisman/unicode into vfs.misc

Merge case-insensitive updates from Gabriel Krisman Bertazi:

- Patch case-insensitive lookup by trying the case-exact comparison
  first, before falling back to costly utf8 casefolded comparison.

- Fix to forbid using a case-insensitive directory as part of an
  overlayfs mount.

- Patchset to ensure d_op are set at d_alloc time for fscrypt and
  casefold volumes, ensuring filesystem dentries will all have the
  correct ops, whether they come from a lookup or not.

* tag 'for-next-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/krisman/unicode:
  libfs: Drop generic_set_encrypted_ci_d_ops
  ubifs: Configure dentry operations at dentry-creation time
  f2fs: Configure dentry operations at dentry-creation time
  ext4: Configure dentry operations at dentry-creation time
  libfs: Add helper to choose dentry operations at mount-time
  libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops
  fscrypt: Drop d_revalidate once the key is added
  fscrypt: Drop d_revalidate for valid dentries during lookup
  fscrypt: Factor out a helper to configure the lookup dentry
  ovl: Always reject mounting over case-insensitive directories
  libfs: Attempt exact-match comparison first during casefolded lookup

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-03-07 11:55:41 +01:00
Gabriel Krisman Bertazi
101c3fad29 libfs: Drop generic_set_encrypted_ci_d_ops
No filesystems depend on it anymore, and it is generally a bad idea.
Since all dentries should have the same set of dentry operations in
case-insensitive capable filesystems, it should be propagated through
->s_d_op.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-11-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:35 -05:00
Gabriel Krisman Bertazi
70dfe3f0d2 libfs: Add helper to choose dentry operations at mount-time
In preparation to drop the similar helper that sets d_op at lookup time,
add a version to set the right d_op filesystem-wide, through sb->s_d_op.
The operations structures are shared across filesystems supporting
fscrypt and/or casefolding, therefore we can keep it in common libfs
code.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-7-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:34 -05:00
Gabriel Krisman Bertazi
2824083db7 ovl: Always reject mounting over case-insensitive directories
overlayfs relies on the filesystem setting DCACHE_OP_HASH or
DCACHE_OP_COMPARE to reject mounting over case-insensitive directories.

Since commit bb9cd9106b ("fscrypt: Have filesystems handle their
d_ops"), we set ->d_op through a hook in ->d_lookup, which
means the root dentry won't have them, causing the mount to accidentally
succeed.

In v6.7-rc7, the following sequence will succeed to mount, but any
dentry other than the root dentry will be a "weird" dentry to ovl and
fail with EREMOTE.

  mkfs.ext4 -O casefold lower.img
  mount -O loop lower.img lower
  mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work ovl /mnt

Mounting on a subdirectory fails, as expected, because DCACHE_OP_HASH
and DCACHE_OP_COMPARE are properly set by ->lookup.

Fix by explicitly rejecting superblocks that allow case-insensitive
dentries. Yes, this will be solved when we move d_op configuration back
to ->s_d_op. Yet, we better have an explicit fix to avoid messing up
again.

While there, re-sort the entries to have more descriptive error messages
first.

Fixes: bb9cd9106b ("fscrypt: Have filesystems handle their d_ops")
Acked-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-2-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
2024-02-27 16:55:34 -05:00
Christian Brauner
a56aefca8d
bdev: make struct bdev_handle private to the block layer
Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-29-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25 12:05:27 +01:00
Christian Brauner
f3a608827d
bdev: open block device as files
Add two new helpers to allow opening block devices as files.
This is not the final infrastructure. This still opens the block device
before opening a struct a file. Until we have removed all references to
struct bdev_handle we can't switch the order:

* Introduce blk_to_file_flags() to translate from block specific to
  flags usable to pen a new file.
* Introduce bdev_file_open_by_{dev,path}().
* Introduce temporary sb_bdev_handle() helper to retrieve a struct
  bdev_handle from a block device file and update places that directly
  reference struct bdev_handle to rely on it.
* Don't count block device openes against the number of open files. A
  bdev_file_open_by_{dev,path}() file is never installed into any
  file descriptor table.

One idea that came to mind was to use kernel_tmpfile_open() which
would require us to pass a path and it would then call do_dentry_open()
going through the regular fops->open::blkdev_open() path. But then we're
back to the problem of routing block specific flags such as
BLK_OPEN_RESTRICT_WRITES through the open path and would have to waste
FMODE_* flags every time we add a new one. With this we can avoid using
a flag bit and we have more leeway in how we open block devices from
bdev_open_by_{dev,path}().

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-1-adbd023e19cc@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25 12:05:21 +01:00
Linus Torvalds
1c892cdd8f vfs-6.8-rc6.fixes
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Merge tag 'vfs-6.8-rc6.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - Fix a memory leak in cachefiles

 - Restrict aio cancellations to I/O submitted through the aio
   interfaces as this is otherwise causing issues for I/O submitted
   via io_uring

 - Increase buffer for afs volume status to avoid overflow

 - Fix a missing zero-length check in unbuffered writes in the
   netfs library. If generic_write_checks() returns zero make
   netfs_unbuffered_write_iter() return right away

 - Prevent a leak in i_dio_count caused by netfs_begin_read() operating
   past i_size. It will return early and leave i_dio_count incremented

 - Account for ipv4 addresses as well as ipv6 addresses when processing
   incoming callbacks in afs

* tag 'vfs-6.8-rc6.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio
  afs: Increase buffer size in afs_update_volume_status()
  afs: Fix ignored callbacks over ipv4
  cachefiles: fix memory leak in cachefiles_add_cache()
  netfs: Fix missing zero-length check in unbuffered write
  netfs: Fix i_dio_count leak on DIO read past i_size
2024-02-22 10:06:29 -08:00
Christian Brauner
4af6ccb469
Merge series 'Use Maple Trees for simple_offset utilities' of https://lore.kernel.org/r/170820083431.6328.16233178852085891453.stgit@91.116.238.104.host.secureserver.net
Pull simple offset series from Chuck Lever

In an effort to address slab fragmentation issues reported a few
months ago, I've replaced the use of xarrays for the directory
offset map in "simple" file systems (including tmpfs).

Thanks to Liam Howlett for helping me get this working with Maple
Trees.

* series 'Use Maple Trees for simple_offset utilities' of https://lore.kernel.org/r/170820083431.6328.16233178852085891453.stgit@91.116.238.104.host.secureserver.net: (6 commits)
  libfs: Convert simple directory offsets to use a Maple Tree
  test_maple_tree: testing the cyclic allocation
  maple_tree: Add mtree_alloc_cyclic()
  libfs: Add simple_offset_empty()
  libfs: Define a minimum directory offset
  libfs: Re-arrange locking in offset_iterate_dir()

Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-22 10:03:26 +01:00
Bart Van Assche
b820de741a
fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio
If kiocb_set_cancel_fn() is called for I/O submitted via io_uring, the
following kernel warning appears:

WARNING: CPU: 3 PID: 368 at fs/aio.c:598 kiocb_set_cancel_fn+0x9c/0xa8
Call trace:
 kiocb_set_cancel_fn+0x9c/0xa8
 ffs_epfile_read_iter+0x144/0x1d0
 io_read+0x19c/0x498
 io_issue_sqe+0x118/0x27c
 io_submit_sqes+0x25c/0x5fc
 __arm64_sys_io_uring_enter+0x104/0xab0
 invoke_syscall+0x58/0x11c
 el0_svc_common+0xb4/0xf4
 do_el0_svc+0x2c/0xb0
 el0_svc+0x2c/0xa4
 el0t_64_sync_handler+0x68/0xb4
 el0t_64_sync+0x1a4/0x1a8

Fix this by setting the IOCB_AIO_RW flag for read and write I/O that is
submitted by libaio.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240215204739.2677806-2-bvanassche@acm.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 16:31:49 +01:00
Chuck Lever
0e4a862174 libfs: Convert simple directory offsets to use a Maple Tree
Test robot reports:
> kernel test robot noticed a -19.0% regression of aim9.disk_src.ops_per_sec on:
>
> commit: a2e459555c ("shmem: stable directory offsets")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

Feng Tang further clarifies that:
> ... the new simple_offset_add()
> called by shmem_mknod() brings extra cost related with slab,
> specifically the 'radix_tree_node', which cause the regression.

Willy's analysis is that, over time, the test workload causes
xa_alloc_cyclic() to fragment the underlying SLAB cache.

This patch replaces the offset_ctx's xarray with a Maple Tree in the
hope that Maple Tree's dense node mode will handle this scenario
more scalably.

In addition, we can widen the simple directory offset maximum to
signed long (as loff_t is also signed).

Suggested-by: Matthew Wilcox <willy@infradead.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202309081306.3ecb3734-oliver.sang@intel.com
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820145616.6328.12620992971699079156.stgit@91.116.238.104.host.secureserver.net
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 09:34:26 +01:00
Chuck Lever
ecba88a3b3 libfs: Add simple_offset_empty()
For simple filesystems that use directory offset mapping, rely
strictly on the directory offset map to tell when a directory has
no children.

After this patch is applied, the emptiness test holds only the RCU
read lock when the directory being tested has no children.

In addition, this adds another layer of confirmation that
simple_offset_add/remove() are working as expected.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820143463.6328.7872919188371286951.stgit@91.116.238.104.host.secureserver.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21 09:34:25 +01:00
Kent Overstreet
ae8c511757
fs: add FS_IOC_GETFSSYSFSPATH
Add a new ioctl for getting the sysfs name of a filesystem - the path
under /sys/fs.

This is going to let us standardize exporting data from sysfs across
filesystems, e.g. time stats.

The returned path will always be of the form "$FSTYP/$SYSFS_IDENTIFIER",
where the sysfs identifier may be a UUID (for bcachefs) or a device name
(xfs).

Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/r/20240207025624.1019754-6-kent.overstreet@linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-12 13:13:59 +01:00
Kent Overstreet
a4af51ce22
fs: super_set_uuid()
Some weird old filesytems have UUID-like things that we wish to expose
as UUIDs, but are smaller; add a length field so that the new
FS_IOC_(GET|SET)UUID ioctls can handle them in generic code.

And add a helper super_set_uuid(), for setting nonstandard length uuids.

Helper is now required for the new FS_IOC_GETUUID ioctl; if
super_set_uuid() hasn't been called, the ioctl won't be supported.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/r/20240207025624.1019754-2-kent.overstreet@linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-08 21:19:59 +01:00
Jan Kara
ccb49011bb quota: Properly annotate i_dquot arrays with __rcu
Dquots pointed to from i_dquot arrays in inodes are protected by
dquot_srcu. Annotate them as such and change .get_dquots callback to
return properly annotated pointer to make sparse happy.

Fixes: b9ba6f94b2 ("quota: remove dqptr_sem")
Signed-off-by: Jan Kara <jack@suse.cz>
2024-02-08 12:04:59 +01:00
Amir Goldstein
853b8d7597
remap_range: merge do_clone_file_range() into vfs_clone_file_range()
commit dfad37051a ("remap_range: move permission hooks out of
do_clone_file_range()") moved the permission hooks from
do_clone_file_range() out to its caller vfs_clone_file_range(),
but left all the fast sanity checks in do_clone_file_range().

This makes the expensive security hooks be called in situations
that they would not have been called before (e.g. fs does not support
clone).

The only reason for the do_clone_file_range() helper was that overlayfs
did not use to be able to call vfs_clone_file_range() from copy up
context with sb_writers lock held.  However, since commit c63e56a4a6
("ovl: do not open/llseek lower file with upper sb_writers held"),
overlayfs just uses an open coded version of vfs_clone_file_range().

Merge_clone_file_range() into vfs_clone_file_range(), restoring the
original order of checks as it was before the regressing commit and adapt
the overlayfs code to call vfs_clone_file_range() before the permission
hooks that were added by commit ca7ab48240 ("ovl: add permission hooks
outside of do_splice_direct()").

Note that in the merge of do_clone_file_range(), the file_start_write()
context was reduced to cover ->remap_file_range() without holding it
over the permission hooks, which was the reason for doing the regressing
commit in the first place.

Reported-and-tested-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401312229.eddeb9a6-oliver.sang@intel.com
Fixes: dfad37051a ("remap_range: move permission hooks out of do_clone_file_range()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20240202102258.1582671-1-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-06 17:07:21 +01:00
Amir Goldstein
3058fca1ed fs: make file_dentry() a simple accessor
file_dentry() is a relic from the days that overlayfs was using files with
a "fake" path, meaning, f_path on overlayfs and f_inode on underlying fs.

In those days, file_dentry() was needed to get the underlying fs dentry
that matches f_inode.

Files with "fake" path should not exist nowadays, so make file_dentry() a
simple accessor and use an assertion to make sure that file_dentry() was
not papering over filesystem bugs.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20240202110132.1584111-2-amir73il@gmail.com
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-06 16:54:45 +01:00
Bart Van Assche
fe3944fb24
fs: Move enum rw_hint into a new header file
Move enum rw_hint into a new header file to prepare for using this data
type in the block layer. Add the attribute __packed to reduce the space
occupied by instances of this data type from four bytes to one byte.
Change the data type of i_write_hint from u8 into enum rw_hint.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Chao Yu <chao@kernel.org> # for the F2FS part
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240202203926.2478590-5-bvanassche@acm.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-06 14:30:48 +01:00
Jeff Layton
c69ff40719
filelock: split leases out of struct file_lock
Add a new struct file_lease and move the lease-specific fields from
struct file_lock to it. Convert the appropriate API calls to take
struct file_lease instead, and convert the callers to use them.

There is zero overlap between the lock manager operations for file
locks and the ones for file leases, so split the lease-related
operations off into a new lease_manager_operations struct.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-47-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-05 13:11:44 +01:00
JonasZhou
d3b1a9a778 fs/address_space: move i_mmap_rwsem to mitigate a false sharing with i_mmap.
In the struct address_space, there is a 32-byte gap between i_mmap
and i_mmap_rwsem. Due to the alignment of struct address_space
variables to 8 bytes, in certain situations, i_mmap and i_mmap_rwsem
may end up in the same CACHE line.

While running Unixbench/execl, we observe high false sharing issues
when accessing i_mmap against i_mmap_rwsem. We move i_mmap_rwsem
after i_private_list, ensuring a 64-byte gap between i_mmap and
i_mmap_rwsem.

For Intel Silver machines (2 sockets) using kernel v6.8 rc-2, the score
of Unixbench/execl improves by ~3.94%, and the score of Unixbench/shell
improves by ~3.26%.

Baseline:
-------------------------------------------------------------
  162      546      748    11374       21  0xffff92e266af90c0
-------------------------------------------------------------
        46.89%   44.65%    0.00%    0.00%                 0x0     1       1  0xffffffff86d5fb96       460       258       271     1069        32  [k] __handle_mm_fault          [kernel.vmlinux]  memory.c:2940            0  1
         4.21%    4.41%    0.00%    0.00%                 0x4     1       1  0xffffffff86d0ed54       473       311       288       95        28  [k] filemap_read               [kernel.vmlinux]  atomic.h:23              0  1
         0.00%    0.00%    0.04%    4.76%                 0x8     1       1  0xffffffff86d4bcf1         0         0         0        5         4  [k] vma_interval_tree_remove   [kernel.vmlinux]  rbtree_augmented.h:204   0  1
         6.41%    6.02%    0.00%    0.00%                 0x8     1       1  0xffffffff86d4ba85       411       271       339      210        32  [k] vma_interval_tree_insert   [kernel.vmlinux]  interval_tree.c:23       0  1
         0.00%    0.00%    0.47%   95.24%                0x10     1       1  0xffffffff86d4bd34         0         0         0       74        32  [k] vma_interval_tree_remove   [kernel.vmlinux]  rbtree_augmented.h:339   0  1
         0.37%    0.13%    0.00%    0.00%                0x10     1       1  0xffffffff86d4bb4f       328       212       380        7         5  [k] vma_interval_tree_remove   [kernel.vmlinux]  rbtree_augmented.h:338   0  1
         5.13%    5.08%    0.00%    0.00%                0x10     1       1  0xffffffff86d4bb4b       416       255       357      197        32  [k] vma_interval_tree_remove   [kernel.vmlinux]  rbtree_augmented.h:338   0  1
         1.10%    0.53%    0.00%    0.00%                0x28     1       1  0xffffffff86e06eb8       395       228       351       24        14  [k] do_dentry_open             [kernel.vmlinux]  open.c:966               0  1
         1.10%    2.14%   57.07%    0.00%                0x38     1       1  0xffffffff878c9225      1364       792       462     7003        32  [k] down_write                 [kernel.vmlinux]  atomic64_64.h:109        0  1
         0.00%    0.00%    0.01%    0.00%                0x38     1       1  0xffffffff878c8e75         0         0       252        3         2  [k] rwsem_down_write_slowpath  [kernel.vmlinux]  atomic64_64.h:109        0  1
         0.00%    0.13%    0.00%    0.00%                0x38     1       1  0xffffffff878c8e23         0       596        63        2         2  [k] rwsem_down_write_slowpath  [kernel.vmlinux]  atomic64_64.h:15         0  1
         2.38%    2.94%    6.53%    0.00%                0x38     1       1  0xffffffff878c8ccb      1150       818       570     1197        32  [k] rwsem_down_write_slowpath  [kernel.vmlinux]  atomic64_64.h:109        0  1
        30.59%   32.22%    0.00%    0.00%                0x38     1       1  0xffffffff878c8cb4       423       251       380      648        32  [k] rwsem_down_write_slowpath  [kernel.vmlinux]  atomic64_64.h:15         0  1
         1.83%    1.74%   35.88%    0.00%                0x38     1       1  0xffffffff86b4f833      1217      1112       565     4586        32  [k] up_write                   [kernel.vmlinux]  atomic64_64.h:91         0  1

with this change:
-------------------------------------------------------------
  360       12      300       57       35  0xffff982cdae76400
-------------------------------------------------------------
        50.00%   59.67%    0.00%    0.00%                 0x0     1       1  0xffffffff8215fb86       352       200       191      558        32  [k] __handle_mm_fault         [kernel.vmlinux]  memory.c:2940            0  1
         8.33%    5.00%    0.00%    0.00%                 0x4     1       1  0xffffffff8210ed44       370       284       263       42        24  [k] filemap_read              [kernel.vmlinux]  atomic.h:23              0  1
         0.00%    0.00%    5.26%    2.86%                 0x8     1       1  0xffffffff8214bce1         0         0         0        4         4  [k] vma_interval_tree_remove  [kernel.vmlinux]  rbtree_augmented.h:204   0  1
        33.33%   14.33%    0.00%    0.00%                 0x8     1       1  0xffffffff8214ba75       344       186       219      140        32  [k] vma_interval_tree_insert  [kernel.vmlinux]  interval_tree.c:23       0  1
         0.00%    0.00%   94.74%   97.14%                0x10     1       1  0xffffffff8214bd24         0         0         0       88        29  [k] vma_interval_tree_remove  [kernel.vmlinux]  rbtree_augmented.h:339   0  1
         8.33%   20.00%    0.00%    0.00%                0x10     1       1  0xffffffff8214bb3b       296       209       226      167        31  [k] vma_interval_tree_remove  [kernel.vmlinux]  rbtree_augmented.h:338   0  1
         0.00%    0.67%    0.00%    0.00%                0x28     1       1  0xffffffff82206f45         0       140       334        4         3  [k] do_dentry_open            [kernel.vmlinux]  open.c:966               0  1
         0.00%    0.33%    0.00%    0.00%                0x38     1       1  0xffffffff8250a6c4         0       286       126        5         5  [k] errseq_sample             [kernel.vmlinux]  errseq.c:125             0

Signed-off-by: JonasZhou <JonasZhou@zhaoxin.com>
Link: https://lore.kernel.org/r/20240202083304.10995-1-JonasZhou-oc@zhaoxin.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-05 12:56:26 +01:00
Baokun Li
d8f899d13d fs: make the i_size_read/write helpers be smp_load_acquire/store_release()
In [Link] Linus mentions that acquire/release makes it clear which
_particular_ memory accesses are the ordered ones, and it's unlikely
to make any performance difference, so it's much better to pair up
the release->acquire ordering than have a "wmb->rmb" ordering.

=========================================================
 update pagecache
 folio_mark_uptodate(folio)
   smp_wmb()
   set_bit PG_uptodate

 === ↑↑↑ STLR ↑↑↑ === smp_store_release(&inode->i_size, i_size)

 folio_test_uptodate(folio)
   test_bit PG_uptodate
   smp_rmb()

 === ↓↓↓ LDAR ↓↓↓ === smp_load_acquire(&inode->i_size)

 copy_page_to_iter()
=========================================================

Calling smp_store_release() in i_size_write() ensures that the data
in the page and the PG_uptodate bit are updated before the isize is
updated, and calling smp_load_acquire() in i_size_read ensures that
it will not read a newer isize than the data in the page. Therefore,
this avoids buffered read-write inconsistencies caused by Load-Load
reordering.

Link: https://lore.kernel.org/r/CAHk-=wifOnmeJq+sn+2s-P46zw0SFEbw9BSCGgp2c5fYPtRPGw@mail.gmail.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240124142857.4146716-2-libaokun1@huawei.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-25 17:23:51 +01:00
Christian Brauner
0000ff2523 Merge tag 'exportfs-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/cel/linux
Merge exportfs fixes from Chuck Lever:

* tag 'exportfs-6.9' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  fs: Create a generic is_dot_dotdot() utility
  exportfs: fix the fallback implementation of the get_name export operation

Link: https://lore.kernel.org/r/BDC2AEB4-7085-4A7C-8DE8-A659FE1DBA6A@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-23 17:56:30 +01:00
Chuck Lever
42c3732fa8 fs: Create a generic is_dot_dotdot() utility
De-duplicate the same functionality in several places by hoisting
the is_dot_dotdot() utility function into linux/fs.h.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2024-01-23 10:58:56 -05:00
Rich Felker
73fa7547c7 vfs: add RWF_NOAPPEND flag for pwritev2
The pwrite function, originally defined by POSIX (thus the "p"), is
defined to ignore O_APPEND and write at the offset passed as its
argument. However, historically Linux honored O_APPEND if set and
ignored the offset. This cannot be changed due to stability policy,
but is documented in the man page as a bug.

Now that there's a pwritev2 syscall providing a superset of the pwrite
functionality that has a flags argument, the conforming behavior can
be offered to userspace via a new flag. Since pwritev2 checks flag
validity (in kiocb_set_rw_flags) and reports unknown ones with
EOPNOTSUPP, callers will not get wrong behavior on old kernels that
don't support the new flag; the error is reported and the caller can
decide how to handle it.

Signed-off-by: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20200831153207.GO3265@brightrain.aerifal.cx
Reviewed-by: Jann Horn <jannh@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-01-22 15:33:37 +01:00
Linus Torvalds
16df6e07d6 vfs-6.8.netfs
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Merge tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull netfs updates from Christian Brauner:
 "This extends the netfs helper library that network filesystems can use
  to replace their own implementations. Both afs and 9p are ported. cifs
  is ready as well but the patches are way bigger and will be routed
  separately once this is merged. That will remove lots of code as well.

  The overal goal is to get high-level I/O and knowledge of the page
  cache and ouf of the filesystem drivers. This includes knowledge about
  the existence of pages and folios

  The pull request converts afs and 9p. This removes about 800 lines of
  code from afs and 300 from 9p. For 9p it is now possible to do writes
  in larger than a page chunks. Additionally, multipage folio support
  can be turned on for 9p. Separate patches exist for cifs removing
  another 2000+ lines. I've included detailed information in the
  individual pulls I took.

  Summary:

   - Add NFS-style (and Ceph-style) locking around DIO vs buffered I/O
     calls to prevent these from happening at the same time.

   - Support for direct and unbuffered I/O.

   - Support for write-through caching in the page cache.

   - O_*SYNC and RWF_*SYNC writes use write-through rather than writing
     to the page cache and then flushing afterwards.

   - Support for write-streaming.

   - Support for write grouping.

   - Skip reads for which the server could only return zeros or EOF.

   - The fscache module is now part of the netfs library and the
     corresponding maintainer entry is updated.

   - Some helpers from the fscache subsystem are renamed to mark them as
     belonging to the netfs library.

   - Follow-up fixes for the netfs library.

   - Follow-up fixes for the 9p conversion"

* tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (50 commits)
  netfs: Fix wrong #ifdef hiding wait
  cachefiles: Fix signed/unsigned mixup
  netfs: Fix the loop that unmarks folios after writing to the cache
  netfs: Fix interaction between write-streaming and cachefiles culling
  netfs: Count DIO writes
  netfs: Mark netfs_unbuffered_write_iter_locked() static
  netfs: Fix proc/fs/fscache symlink to point to "netfs" not "../netfs"
  netfs: Rearrange netfs_io_subrequest to put request pointer first
  9p: Use length of data written to the server in preference to error
  9p: Do a couple of cleanups
  9p: Fix initialisation of netfs_inode for 9p
  cachefiles: Fix __cachefiles_prepare_write()
  9p: Use netfslib read/write_iter
  afs: Use the netfs write helpers
  netfs: Export the netfs_sreq tracepoint
  netfs: Optimise away reads above the point at which there can be no data
  netfs: Implement a write-through caching option
  netfs: Provide a launder_folio implementation
  netfs: Provide a writepages implementation
  netfs, cachefiles: Pass upper bound length to allow expansion
  ...
2024-01-19 09:10:23 -08:00
Linus Torvalds
6c1dd1fe5d integrity-v6.8
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Merge tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:

 - Add a new IMA/EVM maintainer and reviewer

 - Disable EVM on overlayfs

   The EVM HMAC and the original file signatures contain filesystem
   specific metadata (e.g. i_ino, i_generation and s_uuid), preventing
   the security.evm xattr from directly being copied up to the overlay.
   Further before calculating and writing out the overlay file's EVM
   HMAC, EVM must first verify the existing backing file's
   'security.evm' value.

   For now until a solution is developed, disable EVM on overlayfs.

 - One bug fix and two cleanups

* tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  overlay: disable EVM
  evm: add support to disable EVM on unsupported filesystems
  evm: don't copy up 'security.evm' xattr
  MAINTAINERS: Add Eric Snowberg as a reviewer to IMA
  MAINTAINERS: Add Roberto Sassu as co-maintainer to IMA and EVM
  KEYS: encrypted: Add check for strsep
  ima: Remove EXPERIMENTAL from Kconfig
  ima: Reword IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
2024-01-09 13:24:06 -08:00
Linus Torvalds
fb46e22a9e Many singleton patches against the MM code. The patch series which
are included in this merge do the following:
 
 - Peng Zhang has done some mapletree maintainance work in the
   series
 
 	"maple_tree: add mt_free_one() and mt_attr() helpers"
 	"Some cleanups of maple tree"
 
 - In the series "mm: use memmap_on_memory semantics for dax/kmem"
   Vishal Verma has altered the interworking between memory-hotplug
   and dax/kmem so that newly added 'device memory' can more easily
   have its memmap placed within that newly added memory.
 
 - Matthew Wilcox continues folio-related work (including a few
   fixes) in the patch series
 
 	"Add folio_zero_tail() and folio_fill_tail()"
 	"Make folio_start_writeback return void"
 	"Fix fault handler's handling of poisoned tail pages"
 	"Convert aops->error_remove_page to ->error_remove_folio"
 	"Finish two folio conversions"
 	"More swap folio conversions"
 
 - Kefeng Wang has also contributed folio-related work in the series
 
 	"mm: cleanup and use more folio in page fault"
 
 - Jim Cromie has improved the kmemleak reporting output in the
   series "tweak kmemleak report format".
 
 - In the series "stackdepot: allow evicting stack traces" Andrey
   Konovalov to permits clients (in this case KASAN) to cause
   eviction of no longer needed stack traces.
 
 - Charan Teja Kalla has fixed some accounting issues in the page
   allocator's atomic reserve calculations in the series "mm:
   page_alloc: fixes for high atomic reserve caluculations".
 
 - Dmitry Rokosov has added to the samples/ dorectory some sample
   code for a userspace memcg event listener application.  See the
   series "samples: introduce cgroup events listeners".
 
 - Some mapletree maintanance work from Liam Howlett in the series
   "maple_tree: iterator state changes".
 
 - Nhat Pham has improved zswap's approach to writeback in the
   series "workload-specific and memory pressure-driven zswap
   writeback".
 
 - DAMON/DAMOS feature and maintenance work from SeongJae Park in
   the series
 
 	"mm/damon: let users feed and tame/auto-tune DAMOS"
 	"selftests/damon: add Python-written DAMON functionality tests"
 	"mm/damon: misc updates for 6.8"
 
 - Yosry Ahmed has improved memcg's stats flushing in the series
   "mm: memcg: subtree stats flushing and thresholds".
 
 - In the series "Multi-size THP for anonymous memory" Ryan Roberts
   has added a runtime opt-in feature to transparent hugepages which
   improves performance by allocating larger chunks of memory during
   anonymous page faults.
 
 - Matthew Wilcox has also contributed some cleanup and maintenance
   work against eh buffer_head code int he series "More buffer_head
   cleanups".
 
 - Suren Baghdasaryan has done work on Andrea Arcangeli's series
   "userfaultfd move option".  UFFDIO_MOVE permits userspace heap
   compaction algorithms to move userspace's pages around rather than
   UFFDIO_COPY'a alloc/copy/free.
 
 - Stefan Roesch has developed a "KSM Advisor", in the series
   "mm/ksm: Add ksm advisor".  This is a governor which tunes KSM's
   scanning aggressiveness in response to userspace's current needs.
 
 - Chengming Zhou has optimized zswap's temporary working memory
   use in the series "mm/zswap: dstmem reuse optimizations and
   cleanups".
 
 - Matthew Wilcox has performed some maintenance work on the
   writeback code, both code and within filesystems.  The series is
   "Clean up the writeback paths".
 
 - Andrey Konovalov has optimized KASAN's handling of alloc and
   free stack traces for secondary-level allocators, in the series
   "kasan: save mempool stack traces".
 
 - Andrey also performed some KASAN maintenance work in the series
   "kasan: assorted clean-ups".
 
 - David Hildenbrand has gone to town on the rmap code.  Cleanups,
   more pte batching, folio conversions and more.  See the series
   "mm/rmap: interface overhaul".
 
 - Kinsey Ho has contributed some maintenance work on the MGLRU
   code in the series "mm/mglru: Kconfig cleanup".
 
 - Matthew Wilcox has contributed lruvec page accounting code
   cleanups in the series "Remove some lruvec page accounting
   functions".
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Merge tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Peng Zhang has done some mapletree maintainance work in the series

	'maple_tree: add mt_free_one() and mt_attr() helpers'
	'Some cleanups of maple tree'

   - In the series 'mm: use memmap_on_memory semantics for dax/kmem'
     Vishal Verma has altered the interworking between memory-hotplug
     and dax/kmem so that newly added 'device memory' can more easily
     have its memmap placed within that newly added memory.

   - Matthew Wilcox continues folio-related work (including a few fixes)
     in the patch series

	'Add folio_zero_tail() and folio_fill_tail()'
	'Make folio_start_writeback return void'
	'Fix fault handler's handling of poisoned tail pages'
	'Convert aops->error_remove_page to ->error_remove_folio'
	'Finish two folio conversions'
	'More swap folio conversions'

   - Kefeng Wang has also contributed folio-related work in the series

	'mm: cleanup and use more folio in page fault'

   - Jim Cromie has improved the kmemleak reporting output in the series
     'tweak kmemleak report format'.

   - In the series 'stackdepot: allow evicting stack traces' Andrey
     Konovalov to permits clients (in this case KASAN) to cause eviction
     of no longer needed stack traces.

   - Charan Teja Kalla has fixed some accounting issues in the page
     allocator's atomic reserve calculations in the series 'mm:
     page_alloc: fixes for high atomic reserve caluculations'.

   - Dmitry Rokosov has added to the samples/ dorectory some sample code
     for a userspace memcg event listener application. See the series
     'samples: introduce cgroup events listeners'.

   - Some mapletree maintanance work from Liam Howlett in the series
     'maple_tree: iterator state changes'.

   - Nhat Pham has improved zswap's approach to writeback in the series
     'workload-specific and memory pressure-driven zswap writeback'.

   - DAMON/DAMOS feature and maintenance work from SeongJae Park in the
     series

	'mm/damon: let users feed and tame/auto-tune DAMOS'
	'selftests/damon: add Python-written DAMON functionality tests'
	'mm/damon: misc updates for 6.8'

   - Yosry Ahmed has improved memcg's stats flushing in the series 'mm:
     memcg: subtree stats flushing and thresholds'.

   - In the series 'Multi-size THP for anonymous memory' Ryan Roberts
     has added a runtime opt-in feature to transparent hugepages which
     improves performance by allocating larger chunks of memory during
     anonymous page faults.

   - Matthew Wilcox has also contributed some cleanup and maintenance
     work against eh buffer_head code int he series 'More buffer_head
     cleanups'.

   - Suren Baghdasaryan has done work on Andrea Arcangeli's series
     'userfaultfd move option'. UFFDIO_MOVE permits userspace heap
     compaction algorithms to move userspace's pages around rather than
     UFFDIO_COPY'a alloc/copy/free.

   - Stefan Roesch has developed a 'KSM Advisor', in the series 'mm/ksm:
     Add ksm advisor'. This is a governor which tunes KSM's scanning
     aggressiveness in response to userspace's current needs.

   - Chengming Zhou has optimized zswap's temporary working memory use
     in the series 'mm/zswap: dstmem reuse optimizations and cleanups'.

   - Matthew Wilcox has performed some maintenance work on the writeback
     code, both code and within filesystems. The series is 'Clean up the
     writeback paths'.

   - Andrey Konovalov has optimized KASAN's handling of alloc and free
     stack traces for secondary-level allocators, in the series 'kasan:
     save mempool stack traces'.

   - Andrey also performed some KASAN maintenance work in the series
     'kasan: assorted clean-ups'.

   - David Hildenbrand has gone to town on the rmap code. Cleanups, more
     pte batching, folio conversions and more. See the series 'mm/rmap:
     interface overhaul'.

   - Kinsey Ho has contributed some maintenance work on the MGLRU code
     in the series 'mm/mglru: Kconfig cleanup'.

   - Matthew Wilcox has contributed lruvec page accounting code cleanups
     in the series 'Remove some lruvec page accounting functions'"

* tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (361 commits)
  mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
  mm, treewide: introduce NR_PAGE_ORDERS
  selftests/mm: add separate UFFDIO_MOVE test for PMD splitting
  selftests/mm: skip test if application doesn't has root privileges
  selftests/mm: conform test to TAP format output
  selftests: mm: hugepage-mmap: conform to TAP format output
  selftests/mm: gup_test: conform test to TAP format output
  mm/selftests: hugepage-mremap: conform test to TAP format output
  mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
  mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
  mm/memcontrol: remove __mod_lruvec_page_state()
  mm/khugepaged: use a folio more in collapse_file()
  slub: use a folio in __kmalloc_large_node
  slub: use folio APIs in free_large_kmalloc()
  slub: use alloc_pages_node() in alloc_slab_page()
  mm: remove inc/dec lruvec page state functions
  mm: ratelimit stat flush from workingset shrinker
  kasan: stop leaking stack trace handles
  mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE
  mm/mglru: add dummy pmd_dirty()
  ...
2024-01-09 11:18:47 -08:00
Linus Torvalds
bb93c5ed45 vfs-6.8.rw
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Merge tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs rw updates from Christian Brauner:
 "This contains updates from Amir for read-write backing file helpers
  for stacking filesystems such as overlayfs:

   - Fanotify is currently in the process of introducing pre content
     events. Roughly, a new permission event will be added indicating
     that it is safe to write to the file being accessed. These events
     are used by hierarchical storage managers to e.g., fill the content
     of files on first access.

     During that work we noticed that our current permission checking is
     inconsistent in rw_verify_area() and remap_verify_area().
     Especially in the splice code permission checking is done multiple
     times. For example, one time for the whole range and then again for
     partial ranges inside the iterator.

     In addition, we mostly do permission checking before we call
     file_start_write() except for a few places where we call it after.
     For pre-content events we need such permission checking to be done
     before file_start_write(). So this is a nice reason to clean this
     all up.

     After this series, all permission checking is done before
     file_start_write().

     As part of this cleanup we also massaged the splice code a bit. We
     got rid of a few helpers because we are alredy drowning in special
     read-write helpers. We also cleaned up the return types for splice
     helpers.

   - Introduce generic read-write helpers for backing files. This lifts
     some overlayfs code to common code so it can be used by the FUSE
     passthrough work coming in over the next cycles. Make Amir and
     Miklos the maintainers for this new subsystem of the vfs"

* tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
  fs: fix __sb_write_started() kerneldoc formatting
  fs: factor out backing_file_mmap() helper
  fs: factor out backing_file_splice_{read,write}() helpers
  fs: factor out backing_file_{read,write}_iter() helpers
  fs: prepare for stackable filesystems backing file helpers
  fsnotify: optionally pass access range in file permission hooks
  fsnotify: assert that file_start_write() is not held in permission hooks
  fsnotify: split fsnotify_perm() into two hooks
  fs: use splice_copy_file_range() inline helper
  splice: return type ssize_t from all helpers
  fs: use do_splice_direct() for nfsd/ksmbd server-side-copy
  fs: move file_start_write() into direct_splice_actor()
  fs: fork splice_file_range() from do_splice_direct()
  fs: create {sb,file}_write_not_started() helpers
  fs: create file_write_started() helper
  fs: create __sb_write_started() helper
  fs: move kiocb_start_write() into vfs_iocb_iter_write()
  fs: move permission hook out of do_iter_read()
  fs: move permission hook out of do_iter_write()
  fs: move file_start_write() into vfs_iter_write()
  ...
2024-01-08 11:11:51 -08:00
Linus Torvalds
3f6984e730 vfs-6.8.super
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Merge tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs super updates from Christian Brauner:
 "This contains the super work for this cycle including the long-awaited
  series by Jan to make it possible to prevent writing to mounted block
  devices:

   - Writing to mounted devices is dangerous and can lead to filesystem
     corruption as well as crashes. Furthermore syzbot comes with more
     and more involved examples how to corrupt block device under a
     mounted filesystem leading to kernel crashes and reports we can do
     nothing about. Add tracking of writers to each block device and a
     kernel cmdline argument which controls whether other writeable
     opens to block devices open with BLK_OPEN_RESTRICT_WRITES flag are
     allowed.

     Note that this effectively only prevents modification of the
     particular block device's page cache by other writers. The actual
     device content can still be modified by other means - e.g. by
     issuing direct scsi commands, by doing writes through devices lower
     in the storage stack (e.g. in case loop devices, DM, or MD are
     involved) etc. But blocking direct modifications of the block
     device page cache is enough to give filesystems a chance to perform
     data validation when loading data from the underlying storage and
     thus prevent kernel crashes.

     Syzbot can use this cmdline argument option to avoid uninteresting
     crashes. Also users whose userspace setup does not need writing to
     mounted block devices can set this option for hardening. We expect
     that this will be interesting to quite a few workloads.

     Btrfs is currently opted out of this because they still haven't
     merged patches we require for this to work from three kernel
     releases ago.

   - Reimplement block device freezing and thawing as holder operations
     on the block device.

     This allows us to extend block device freezing to all devices
     associated with a superblock and not just the main device. It also
     allows us to remove get_active_super() and thus another function
     that scans the global list of superblocks.

     Freezing via additional block devices only works if the filesystem
     chooses to use @fs_holder_ops for these additional devices as well.
     That currently only includes ext4 and xfs.

     Earlier releases switched get_tree_bdev() and mount_bdev() to use
     @fs_holder_ops. The remaining nilfs2 open-coded version of
     mount_bdev() has been converted to rely on @fs_holder_ops as well.
     So block device freezing for the main block device will continue to
     work as before.

     There should be no regressions in functionality. The only special
     case is btrfs where block device freezing for the main block device
     never worked because sb->s_bdev isn't set. Block device freezing
     for btrfs can be fixed once they can switch to @fs_holder_ops but
     that can happen whenever they're ready"

* tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits)
  block: Fix a memory leak in bdev_open_by_dev()
  super: don't bother with WARN_ON_ONCE()
  super: massage wait event mechanism
  ext4: Block writes to journal device
  xfs: Block writes to log device
  fs: Block writes to mounted block devices
  btrfs: Do not restrict writes to btrfs devices
  block: Add config option to not allow writing to mounted devices
  block: Remove blkdev_get_by_*() functions
  bcachefs: Convert to bdev_open_by_path()
  fs: handle freezing from multiple devices
  fs: remove dead check
  nilfs2: simplify device handling
  fs: streamline thaw_super_locked
  ext4: simplify device handling
  xfs: simplify device handling
  fs: simplify setup_bdev_super() calls
  blkdev: comment fs_holder_ops
  porting: document block device freeze and thaw changes
  fs: remove unused helper
  ...
2024-01-08 10:43:51 -08:00
Vegard Nossum
c39e2ae394
fs: fix __sb_write_started() kerneldoc formatting
When running 'make htmldocs', I see the following warning:

  Documentation/filesystems/api-summary:14: ./include/linux/fs.h:1659: WARNING: Definition list ends without a blank line; unexpected unindent.

The official guidance [1] seems to be to use lists, which will prevent
both the "unexpected unindent" warning as well as ensure that each line
is formatted on a separate line in the HTML output instead of being
all considered a single paragraph.

[1]: https://docs.kernel.org/doc-guide/kernel-doc.html#return-values

Fixes: 8802e580ee ("fs: create __sb_write_started() helper")
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20231228100608.3123987-1-vegard.nossum@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-28 11:40:40 +01:00
David Howells
c9c4ff12df netfs: Move pinning-for-writeback from fscache to netfs
Move the resource pinning-for-writeback from fscache code to netfslib code.
This is used to keep a cache backing object pinned whilst we have dirty
pages on the netfs inode in the pagecache such that VM writeback will be
able to reach it.

Whilst we're at it, switch the parameters of netfs_unpin_writeback() to
match ->write_inode() so that it can be used for that directly.

Note that this mechanism could be more generically useful than that for
network filesystems.  Quite often they have to keep around other resources
(e.g. authentication tokens or network connections) until the writeback is
complete.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2023-12-24 15:08:49 +00:00
Amir Goldstein
f91a704f71 fs: prepare for stackable filesystems backing file helpers
In preparation for factoring out some backing file io helpers from
overlayfs, move backing_file_open() into a new file fs/backing-file.c
and header.

Add a MAINTAINERS entry for stackable filesystems and add a Kconfig
FS_STACK which stackable filesystems need to select.

For now, the backing_file struct, the backing_file alloc/free functions
and the backing_file_real_path() accessor remain internal to file_table.c.
We may change that in the future.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2023-12-23 16:35:08 +02:00
Christian Brauner
2137e15642
Merge branch 'vfs.file'
Bring in the changes to the file infrastructure for this cycle. Mostly
cleanups and some performance tweaks.

* file: remove __receive_fd()
* file: stop exposing receive_fd_user()
* fs: replace f_rcuhead with f_task_work
* file: remove pointless wrapper
* file: s/close_fd_get_file()/file_close_fd()/g
* Improve __fget_files_rcu() code generation (and thus __fget_light())
* file: massage cleanup of files that failed to open

Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-21 13:21:52 +01:00
Andrei Vagin
3efdc78fdc
fs/proc: show correct device and inode numbers in /proc/pid/maps
/proc/pid/maps shows device and inode numbers of vma->vm_file-s. Here is
an issue. If a mapped file is on a stackable file system (e.g.,
overlayfs), vma->vm_file is a backing file whose f_inode is on the
underlying filesystem. To show correct numbers, we need to get a user
file and shows its numbers. The same trick is used to show file paths in
/proc/pid/maps.

Cc: Alexander Mikhalitsyn <alexander@mihalicyn.com>
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Andrei Vagin <avagin@google.com>
Link: https://lore.kernel.org/r/20231214064439.1023011-1-avagin@google.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-21 13:17:54 +01:00
Mimi Zohar
cd708c938f evm: add support to disable EVM on unsupported filesystems
Identify EVM unsupported filesystems by defining a new flag
SB_I_EVM_UNSUPPORTED.

Don't verify, write, remove or update 'security.evm' on unsupported
filesystems.

Acked-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2023-12-20 07:40:07 -05:00
Amir Goldstein
705bcfcbde
fs: use splice_copy_file_range() inline helper
generic_copy_file_range() is just a wrapper around splice_file_range(),
which caps the maximum copy length.

The only caller of splice_file_range(), namely __ceph_copy_file_range()
is already ready to cope with short copy.

Move the length capping into splice_file_range() and replace the exported
symbol generic_copy_file_range() with a simple inline helper.

Suggested-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-fsdevel/20231204083849.GC32438@lst.de/
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231212094440.250945-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12 16:20:02 +01:00
Christian Brauner
372a34e66f
fs: replace f_rcuhead with f_task_work
The naming is actively misleading since we switched to
SLAB_TYPESAFE_BY_RCU. rcu_head is #define callback_head. Use
callback_head directly and rename f_rcuhead to f_task_work.

Add comments in there to explain what it's used for.

Link: https://lore.kernel.org/r/20231130-vfs-files-fixes-v1-3-e73ca6f4ea83@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12 14:24:13 +01:00
Matthew Wilcox (Oracle)
af7628d6ec fs: convert error_remove_page to error_remove_folio
There were already assertions that we were not passing a tail page to
error_remove_page(), so make the compiler enforce that by converting
everything to pass and use a folio.

Link: https://lkml.kernel.org/r/20231117161447.2461643-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-10 16:51:42 -08:00
Amir Goldstein
488e8f6852 fs: fork splice_file_range() from do_splice_direct()
In preparation of calling do_splice_direct() without file_start_write()
held, create a new helper splice_file_range(), to be called from context
of ->copy_file_range() methods instead of do_splice_direct().

Currently, the only difference is that splice_file_range() does not take
flags argument and that it asserts that file_start_write() is held, but
we factor out a common helper do_splice_direct_actor() that will be used
later.

Use the new helper from __ceph_copy_file_range(), that was incorrectly
passing to do_splice_direct() the copy flags argument as splice flags.
The value of copy flags in ceph is always 0, so it is a smenatic bug fix.

Move the declaration of both helpers to linux/splice.h.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231130141624.3338942-2-amir73il@gmail.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-01 11:39:50 +01:00
Amir Goldstein
21b32e6a0a fs: create {sb,file}_write_not_started() helpers
Create new helpers {sb,file}_write_not_started() that can be used
to assert that sb_start_write() is not held.

This is needed for fanotify "pre content" events.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-17-amir73il@gmail.com
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:39:19 +01:00
Amir Goldstein
3d5cd4911e fs: create file_write_started() helper
Convenience wrapper for sb_write_started(file_inode(inode)->i_sb)), which
has a single occurrence in the code right now.

Document the false negatives of those helpers, which makes them unusable
to assert that sb_start_write() is not held.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-16-amir73il@gmail.com
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:39:19 +01:00
Amir Goldstein
8802e580ee fs: create __sb_write_started() helper
Similar to sb_write_started() for use by other sb freeze levels.

Unlike the boolean sb_write_started(), this helper returns a tristate
to distiguish the cases of lockdep disabled or unknown lock state.

This is needed for fanotify "pre content" events.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-15-amir73il@gmail.com
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-24 10:39:13 +01:00
Matthew Wilcox (Oracle)
600f111ef5 fs: Rename mapping private members
It is hard to find where mapping->private_lock, mapping->private_list and
mapping->private_data are used, due to private_XXX being a relatively
common name for variables and structure members in the kernel.  To fit
with other members of struct address_space, rename them all to have an
i_ prefix.  Tested with an allmodconfig build.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20231117215823.2821906-1-willy@infradead.org
Acked-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-21 11:57:10 +01:00
Christian Brauner
7366f8b6fc
fs: handle freezing from multiple devices
Before [1] freezing a filesystems through the block layer only worked
for the main block device as the owning superblock of additional block
devices could not be found. Any filesystem that made use of multiple
block devices would only be freezable via it's main block device.

For example, consider xfs over device mapper with /dev/dm-0 as main
block device and /dev/dm-1 as external log device. Two freeze requests
before [1]:

(1) dmsetup suspend /dev/dm-0 on the main block device

    bdev_freeze(dm-0)
    -> dm-0->bd_fsfreeze_count++
    -> freeze_super(xfs-sb)

    The owning superblock is found and the filesystem gets frozen.
    Returns 0.

(2) dmsetup suspend /dev/dm-1 on the log device

    bdev_freeze(dm-1)
    -> dm-1->bd_fsfreeze_count++

    The owning superblock isn't found and only the block device freeze
    count is incremented. Returns 0.

Two freeze requests after [1]:

(1') dmsetup suspend /dev/dm-0 on the main block device

    bdev_freeze(dm-0)
    -> dm-0->bd_fsfreeze_count++
    -> freeze_super(xfs-sb)

    The owning superblock is found and the filesystem gets frozen.
    Returns 0.

(2') dmsetup suspend /dev/dm-1 on the log device

    bdev_freeze(dm-0)
    -> dm-0->bd_fsfreeze_count++
    -> freeze_super(xfs-sb)

    The owning superblock is found and the filesystem gets frozen.
    Returns -EBUSY.

When (2') is called we initiate a freeze from another block device of
the same superblock. So we increment the bd_fsfreeze_count for that
additional block device. But we now also find the owning superblock for
additional block devices and call freeze_super() again which reports
-EBUSY.

This can be reproduced through xfstests via:

    mkfs.xfs -f -m crc=1,reflink=1,rmapbt=1, -i sparse=1 -lsize=1g,logdev=/dev/nvme1n1p4 /dev/nvme1n1p3
    mkfs.xfs -f -m crc=1,reflink=1,rmapbt=1, -i sparse=1 -lsize=1g,logdev=/dev/nvme1n1p6 /dev/nvme1n1p5

    FSTYP=xfs
    export TEST_DEV=/dev/nvme1n1p3
    export TEST_DIR=/mnt/test
    export TEST_LOGDEV=/dev/nvme1n1p4
    export SCRATCH_DEV=/dev/nvme1n1p5
    export SCRATCH_MNT=/mnt/scratch
    export SCRATCH_LOGDEV=/dev/nvme1n1p6
    export USE_EXTERNAL=yes

    sudo ./check generic/311

Current semantics allow two concurrent freezers: one initiated from
userspace via FREEZE_HOLDER_USERSPACE and one initiated from the kernel
via FREEZE_HOLDER_KERNEL. If there are multiple concurrent freeze
requests from either FREEZE_HOLDER_USERSPACE or FREEZE_HOLDER_KERNEL
-EBUSY is returned.

We need to preserve these semantics because as they are uapi via
FIFREEZE and FITHAW ioctl()s. IOW, freezes don't nest for FIFREEZE and
FITHAW. Other kernels consumers rely on non-nesting freezes as well.

With freezes initiated from the block layer freezes need to nest if the
same superblock is frozen via multiple devices. So we need to start
counting the number of freeze requests.

If FREEZE_MAY_NEST is passed alongside FREEZE_HOLDER_KERNEL or
FREEZE_HOLDER_USERSPACE we allow the caller to nest freeze calls.

To accommodate the old semantics we split the freeze counter into two
counting kernel initiated and userspace initiated freezes separately. We
can then also stop recording FREEZE_HOLDER_* in struct sb_writers.

We also simplify freezing by making all concurrent freezers share a
single active superblock reference count instead of having separate
references for kernel and userspace. I don't see why we would need two
active reference counts. Neither FREEZE_HOLDER_KERNEL nor
FREEZE_HOLDER_USERSPACE can put the active reference as long as they are
concurrent freezers anwyay. That was already true before we allowed
nesting freezes.

Survives various fstests runs with different options including the
reproducer, online scrub, and online repair, fsfreze, and so on. Also
survives blktests.

Link: https://lore.kernel.org/linux-block/87bkccnwxc.fsf@debian-BULLSEYE-live-builder-AMD64
Link: https://lore.kernel.org/r/20231104-vfs-multi-device-freeze-v2-2-5b5b69626eac@kernel.org
Fixes: 288d8706abfc ("bdev: implement freeze and thaw holder operations") [1] # no backport needed
Tested-by: Chandan Babu R <chandanbabu@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-18 14:59:25 +01:00
Christian Brauner
434f8d8299
fs: remove get_active_super()
This function is now unused so remove it. One less function that uses
the global superblock list.

Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-6-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-18 14:59:23 +01:00
Linus Torvalds
ecae0bd517 Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
 
 - Kemeng Shi has contributed some compation maintenance work in the
   series "Fixes and cleanups to compaction".
 
 - Joel Fernandes has a patchset ("Optimize mremap during mutual
   alignment within PMD") which fixes an obscure issue with mremap()'s
   pagetable handling during a subsequent exec(), based upon an
   implementation which Linus suggested.
 
 - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the
   following patch series:
 
 	mm/damon: misc fixups for documents, comments and its tracepoint
 	mm/damon: add a tracepoint for damos apply target regions
 	mm/damon: provide pseudo-moving sum based access rate
 	mm/damon: implement DAMOS apply intervals
 	mm/damon/core-test: Fix memory leaks in core-test
 	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval
 
 - In the series "Do not try to access unaccepted memory" Adrian Hunter
   provides some fixups for the recently-added "unaccepted memory' feature.
   To increase the feature's checking coverage.  "Plug a few gaps where
   RAM is exposed without checking if it is unaccepted memory".
 
 - In the series "cleanups for lockless slab shrink" Qi Zheng has done
   some maintenance work which is preparation for the lockless slab
   shrinking code.
 
 - Qi Zheng has redone the earlier (and reverted) attempt to make slab
   shrinking lockless in the series "use refcount+RCU method to implement
   lockless slab shrink".
 
 - David Hildenbrand contributes some maintenance work for the rmap code
   in the series "Anon rmap cleanups".
 
 - Kefeng Wang does more folio conversions and some maintenance work in
   the migration code.  Series "mm: migrate: more folio conversion and
   unification".
 
 - Matthew Wilcox has fixed an issue in the buffer_head code which was
   causing long stalls under some heavy memory/IO loads.  Some cleanups
   were added on the way.  Series "Add and use bdev_getblk()".
 
 - In the series "Use nth_page() in place of direct struct page
   manipulation" Zi Yan has fixed a potential issue with the direct
   manipulation of hugetlb page frames.
 
 - In the series "mm: hugetlb: Skip initialization of gigantic tail
   struct pages if freed by HVO" has improved our handling of gigantic
   pages in the hugetlb vmmemmep optimizaton code.  This provides
   significant boot time improvements when significant amounts of gigantic
   pages are in use.
 
 - Matthew Wilcox has sent the series "Small hugetlb cleanups" - code
   rationalization and folio conversions in the hugetlb code.
 
 - Yin Fengwei has improved mlock()'s handling of large folios in the
   series "support large folio for mlock"
 
 - In the series "Expose swapcache stat for memcg v1" Liu Shixin has
   added statistics for memcg v1 users which are available (and useful)
   under memcg v2.
 
 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
   prctl so that userspace may direct the kernel to not automatically
   propagate the denial to child processes.  The series is named "MDWE
   without inheritance".
 
 - Kefeng Wang has provided the series "mm: convert numa balancing
   functions to use a folio" which does what it says.
 
 - In the series "mm/ksm: add fork-exec support for prctl" Stefan Roesch
   makes is possible for a process to propagate KSM treatment across
   exec().
 
 - Huang Ying has enhanced memory tiering's calculation of memory
   distances.  This is used to permit the dax/kmem driver to use "high
   bandwidth memory" in addition to Optane Data Center Persistent Memory
   Modules (DCPMM).  The series is named "memory tiering: calculate
   abstract distance based on ACPI HMAT"
 
 - In the series "Smart scanning mode for KSM" Stefan Roesch has
   optimized KSM by teaching it to retain and use some historical
   information from previous scans.
 
 - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the
   series "mm: memcg: fix tracking of pending stats updates values".
 
 - In the series "Implement IOCTL to get and optionally clear info about
   PTEs" Peter Xu has added an ioctl to /proc/<pid>/pagemap which permits
   us to atomically read-then-clear page softdirty state.  This is mainly
   used by CRIU.
 
 - Hugh Dickins contributed the series "shmem,tmpfs: general maintenance"
   - a bunch of relatively minor maintenance tweaks to this code.
 
 - Matthew Wilcox has increased the use of the VMA lock over file-backed
   page faults in the series "Handle more faults under the VMA lock".  Some
   rationalizations of the fault path became possible as a result.
 
 - In the series "mm/rmap: convert page_move_anon_rmap() to
   folio_move_anon_rmap()" David Hildenbrand has implemented some cleanups
   and folio conversions.
 
 - In the series "various improvements to the GUP interface" Lorenzo
   Stoakes has simplified and improved the GUP interface with an eye to
   providing groundwork for future improvements.
 
 - Andrey Konovalov has sent along the series "kasan: assorted fixes and
   improvements" which does those things.
 
 - Some page allocator maintenance work from Kemeng Shi in the series
   "Two minor cleanups to break_down_buddy_pages".
 
 - In thes series "New selftest for mm" Breno Leitao has developed
   another MM self test which tickles a race we had between madvise() and
   page faults.
 
 - In the series "Add folio_end_read" Matthew Wilcox provides cleanups
   and an optimization to the core pagecache code.
 
 - Nhat Pham has added memcg accounting for hugetlb memory in the series
   "hugetlb memcg accounting".
 
 - Cleanups and rationalizations to the pagemap code from Lorenzo
   Stoakes, in the series "Abstract vma_merge() and split_vma()".
 
 - Audra Mitchell has fixed issues in the procfs page_owner code's new
   timestamping feature which was causing some misbehaviours.  In the
   series "Fix page_owner's use of free timestamps".
 
 - Lorenzo Stoakes has fixed the handling of new mappings of sealed files
   in the series "permit write-sealed memfd read-only shared mappings".
 
 - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
   series "Batch hugetlb vmemmap modification operations".
 
 - Some buffer_head folio conversions and cleanups from Matthew Wilcox in
   the series "Finish the create_empty_buffers() transition".
 
 - As a page allocator performance optimization Huang Ying has added
   automatic tuning to the allocator's per-cpu-pages feature, in the series
   "mm: PCP high auto-tuning".
 
 - Roman Gushchin has contributed the patchset "mm: improve performance
   of accounted kernel memory allocations" which improves their performance
   by ~30% as measured by a micro-benchmark.
 
 - folio conversions from Kefeng Wang in the series "mm: convert page
   cpupid functions to folios".
 
 - Some kmemleak fixups in Liu Shixin's series "Some bugfix about
   kmemleak".
 
 - Qi Zheng has improved our handling of memoryless nodes by keeping them
   off the allocation fallback list.  This is done in the series "handle
   memoryless nodes more appropriately".
 
 - khugepaged conversions from Vishal Moola in the series "Some
   khugepaged folio conversions".
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Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...
2023-11-02 19:38:47 -10:00
Linus Torvalds
2b93c2c3c0 lsm/stable-6.7 PR 20231030
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Merge tag 'lsm-pr-20231030' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull LSM updates from Paul Moore:

 - Add new credential functions, get_cred_many() and put_cred_many() to
   save some atomic_t operations for a few operations.

   While not strictly LSM related, this patchset had been rotting on the
   mailing lists for some time and since the LSMs do care a lot about
   credentials I thought it reasonable to give this patch a home.

 - Five patches to constify different LSM hook parameters.

 - Fix a spelling mistake.

* tag 'lsm-pr-20231030' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lsm: fix a spelling mistake
  cred: add get_cred_many and put_cred_many
  lsm: constify 'sb' parameter in security_sb_kern_mount()
  lsm: constify 'bprm' parameter in security_bprm_committed_creds()
  lsm: constify 'bprm' parameter in security_bprm_committing_creds()
  lsm: constify 'file' parameter in security_bprm_creds_from_file()
  lsm: constify 'sb' parameter in security_quotactl()
2023-10-30 20:13:17 -10:00
Linus Torvalds
8829687a4a fscrypt updates for 6.7
This update adds support for configuring the crypto data unit size (i.e.
 the granularity of file contents encryption) to be less than the
 filesystem block size. This can allow users to use inline encryption
 hardware in some cases when it wouldn't otherwise be possible.
 
 In addition, there are two commits that are prerequisites for the
 extent-based encryption support that the btrfs folks are working on.
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Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux

Pull fscrypt updates from Eric Biggers:
 "This update adds support for configuring the crypto data unit size
  (i.e. the granularity of file contents encryption) to be less than the
  filesystem block size. This can allow users to use inline encryption
  hardware in some cases when it wouldn't otherwise be possible.

  In addition, there are two commits that are prerequisites for the
  extent-based encryption support that the btrfs folks are working on"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux:
  fscrypt: track master key presence separately from secret
  fscrypt: rename fscrypt_info => fscrypt_inode_info
  fscrypt: support crypto data unit size less than filesystem block size
  fscrypt: replace get_ino_and_lblk_bits with just has_32bit_inodes
  fscrypt: compute max_lblk_bits from s_maxbytes and block size
  fscrypt: make the bounce page pool opt-in instead of opt-out
  fscrypt: make it clearer that key_prefix is deprecated
2023-10-30 10:23:42 -10:00
Linus Torvalds
14ab6d425e vfs-6.7.ctime
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Merge tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull vfs inode time accessor updates from Christian Brauner:
 "This finishes the conversion of all inode time fields to accessor
  functions as discussed on list. Changing timestamps manually as we
  used to do before is error prone. Using accessors function makes this
  robust.

  It does not contain the switch of the time fields to discrete 64 bit
  integers to replace struct timespec and free up space in struct inode.
  But after this, the switch can be trivially made and the patch should
  only affect the vfs if we decide to do it"

* tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits)
  fs: rename inode i_atime and i_mtime fields
  security: convert to new timestamp accessors
  selinux: convert to new timestamp accessors
  apparmor: convert to new timestamp accessors
  sunrpc: convert to new timestamp accessors
  mm: convert to new timestamp accessors
  bpf: convert to new timestamp accessors
  ipc: convert to new timestamp accessors
  linux: convert to new timestamp accessors
  zonefs: convert to new timestamp accessors
  xfs: convert to new timestamp accessors
  vboxsf: convert to new timestamp accessors
  ufs: convert to new timestamp accessors
  udf: convert to new timestamp accessors
  ubifs: convert to new timestamp accessors
  tracefs: convert to new timestamp accessors
  sysv: convert to new timestamp accessors
  squashfs: convert to new timestamp accessors
  server: convert to new timestamp accessors
  client: convert to new timestamp accessors
  ...
2023-10-30 09:47:13 -10:00
Linus Torvalds
7352a6765c vfs-6.7.xattr
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Merge tag 'vfs-6.7.xattr' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull vfs xattr updates from Christian Brauner:
 "The 's_xattr' field of 'struct super_block' currently requires a
  mutable table of 'struct xattr_handler' entries (although each handler
  itself is const). However, no code in vfs actually modifies the
  tables.

  This changes the type of 's_xattr' to allow const tables, and modifies
  existing file systems to move their tables to .rodata. This is
  desirable because these tables contain entries with function pointers
  in them; moving them to .rodata makes it considerably less likely to
  be modified accidentally or maliciously at runtime"

* tag 'vfs-6.7.xattr' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
  const_structs.checkpatch: add xattr_handler
  net: move sockfs_xattr_handlers to .rodata
  shmem: move shmem_xattr_handlers to .rodata
  overlayfs: move xattr tables to .rodata
  xfs: move xfs_xattr_handlers to .rodata
  ubifs: move ubifs_xattr_handlers to .rodata
  squashfs: move squashfs_xattr_handlers to .rodata
  smb: move cifs_xattr_handlers to .rodata
  reiserfs: move reiserfs_xattr_handlers to .rodata
  orangefs: move orangefs_xattr_handlers to .rodata
  ocfs2: move ocfs2_xattr_handlers and ocfs2_xattr_handler_map to .rodata
  ntfs3: move ntfs_xattr_handlers to .rodata
  nfs: move nfs4_xattr_handlers to .rodata
  kernfs: move kernfs_xattr_handlers to .rodata
  jfs: move jfs_xattr_handlers to .rodata
  jffs2: move jffs2_xattr_handlers to .rodata
  hfsplus: move hfsplus_xattr_handlers to .rodata
  hfs: move hfs_xattr_handlers to .rodata
  gfs2: move gfs2_xattr_handlers_max to .rodata
  fuse: move fuse_xattr_handlers to .rodata
  ...
2023-10-30 09:29:44 -10:00
Linus Torvalds
3b3f874cc1 vfs-6.7.misc
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Merge tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Rename and export helpers that get write access to a mount. They
     are used in overlayfs to get write access to the upper mount.

   - Print the pretty name of the root device on boot failure. This
     helps in scenarios where we would usually only print
     "unknown-block(1,2)".

   - Add an internal SB_I_NOUMASK flag. This is another part in the
     endless POSIX ACL saga in a way.

     When POSIX ACLs are enabled via SB_POSIXACL the vfs cannot strip
     the umask because if the relevant inode has POSIX ACLs set it might
     take the umask from there. But if the inode doesn't have any POSIX
     ACLs set then we apply the umask in the filesytem itself. So we end
     up with:

      (1) no SB_POSIXACL -> strip umask in vfs
      (2) SB_POSIXACL    -> strip umask in filesystem

     The umask semantics associated with SB_POSIXACL allowed filesystems
     that don't even support POSIX ACLs at all to raise SB_POSIXACL
     purely to avoid umask stripping. That specifically means NFS v4 and
     Overlayfs. NFS v4 does it because it delegates this to the server
     and Overlayfs because it needs to delegate umask stripping to the
     upper filesystem, i.e., the filesystem used as the writable layer.

     This went so far that SB_POSIXACL is raised eve on kernels that
     don't even have POSIX ACL support at all.

     Stop this blatant abuse and add SB_I_NOUMASK which is an internal
     superblock flag that filesystems can raise to opt out of umask
     handling. That should really only be the two mentioned above. It's
     not that we want any filesystems to do this. Ideally we have all
     umask handling always in the vfs.

   - Make overlayfs use SB_I_NOUMASK too.

   - Now that we have SB_I_NOUMASK, stop checking for SB_POSIXACL in
     IS_POSIXACL() if the kernel doesn't have support for it. This is a
     very old patch but it's only possible to do this now with the wider
     cleanup that was done.

   - Follow-up work on fake path handling from last cycle. Citing mostly
     from Amir:

     When overlayfs was first merged, overlayfs files of regular files
     and directories, the ones that are installed in file table, had a
     "fake" path, namely, f_path is the overlayfs path and f_inode is
     the "real" inode on the underlying filesystem.

     In v6.5, we took another small step by introducing of the
     backing_file container and the file_real_path() helper. This change
     allowed vfs and filesystem code to get the "real" path of an
     overlayfs backing file. With this change, we were able to make
     fsnotify work correctly and report events on the "real" filesystem
     objects that were accessed via overlayfs.

     This method works fine, but it still leaves the vfs vulnerable to
     new code that is not aware of files with fake path. A recent
     example is commit db1d1e8b98 ("IMA: use vfs_getattr_nosec to get
     the i_version"). This commit uses direct referencing to f_path in
     IMA code that otherwise uses file_inode() and file_dentry() to
     reference the filesystem objects that it is measuring.

     This contains work to switch things around: instead of having
     filesystem code opt-in to get the "real" path, have generic code
     opt-in for the "fake" path in the few places that it is needed.

     Is it far more likely that new filesystems code that does not use
     the file_dentry() and file_real_path() helpers will end up causing
     crashes or averting LSM/audit rules if we keep the "fake" path
     exposed by default.

     This change already makes file_dentry() moot, but for now we did
     not change this helper just added a WARN_ON() in ovl_d_real() to
     catch if we have made any wrong assumptions.

     After the dust settles on this change, we can make file_dentry() a
     plain accessor and we can drop the inode argument to ->d_real().

   - Switch struct file to SLAB_TYPESAFE_BY_RCU. This looks like a small
     change but it really isn't and I would like to see everyone on
     their tippie toes for any possible bugs from this work.

     Essentially we've been doing most of what SLAB_TYPESAFE_BY_RCU for
     files since a very long time because of the nasty interactions
     between the SCM_RIGHTS file descriptor garbage collection. So
     extending it makes a lot of sense but it is a subtle change. There
     are almost no places that fiddle with file rcu semantics directly
     and the ones that did mess around with struct file internal under
     rcu have been made to stop doing that because it really was always
     dodgy.

     I forgot to put in the link tag for this change and the discussion
     in the commit so adding it into the merge message:

       https://lore.kernel.org/r/20230926162228.68666-1-mjguzik@gmail.com

  Cleanups:

   - Various smaller pipe cleanups including the removal of a spin lock
     that was only used to protect against writes without pipe_lock()
     from O_NOTIFICATION_PIPE aka watch queues. As that was never
     implemented remove the additional locking from pipe_write().

   - Annotate struct watch_filter with the new __counted_by attribute.

   - Clarify do_unlinkat() cleanup so that it doesn't look like an extra
     iput() is done that would cause issues.

   - Simplify file cleanup when the file has never been opened.

   - Use module helper instead of open-coding it.

   - Predict error unlikely for stale retry.

   - Use WRITE_ONCE() for mount expiry field instead of just commenting
     that one hopes the compiler doesn't get smart.

  Fixes:

   - Fix readahead on block devices.

   - Fix writeback when layztime is enabled and inodes whose timestamp
     is the only thing that changed reside on wb->b_dirty_time. This
     caused excessively large zombie memory cgroup when lazytime was
     enabled as such inodes weren't handled fast enough.

   - Convert BUG_ON() to WARN_ON_ONCE() in open_last_lookups()"

* tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  file, i915: fix file reference for mmap_singleton()
  vfs: Convert BUG_ON to WARN_ON_ONCE in open_last_lookups
  writeback, cgroup: switch inodes with dirty timestamps to release dying cgwbs
  chardev: Simplify usage of try_module_get()
  ovl: rely on SB_I_NOUMASK
  fs: fix umask on NFS with CONFIG_FS_POSIX_ACL=n
  fs: store real path instead of fake path in backing file f_path
  fs: create helper file_user_path() for user displayed mapped file path
  fs: get mnt_writers count for an open backing file's real path
  vfs: stop counting on gcc not messing with mnt_expiry_mark if not asked
  vfs: predict the error in retry_estale as unlikely
  backing file: free directly
  vfs: fix readahead(2) on block devices
  io_uring: use files_lookup_fd_locked()
  file: convert to SLAB_TYPESAFE_BY_RCU
  vfs: shave work on failed file open
  fs: simplify misleading code to remove ambiguity regarding ihold()/iput()
  watch_queue: Annotate struct watch_filter with __counted_by
  fs/pipe: use spinlock in pipe_read() only if there is a watch_queue
  fs/pipe: remove unnecessary spinlock from pipe_write()
  ...
2023-10-30 09:14:19 -10:00
Jan Kara
f4a48bc36c
fs: Convert to bdev_open_by_dev()
Convert mount code to use bdev_open_by_dev() and propagate the handle
around to bdev_release().

Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-19-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-28 13:29:19 +02:00
Christian Brauner
61d4fb0b34
file, i915: fix file reference for mmap_singleton()
Today we got a report at [1] for rcu stalls on the i915 testsuite in [2]
due to the conversion of files to SLAB_TYPSSAFE_BY_RCU. Afaict,
get_file_rcu() goes into an infinite loop trying to carefully verify
that i915->gem.mmap_singleton hasn't changed - see the splat below.

So I stared at this code to figure out what it actually does. It seems
that the i915->gem.mmap_singleton pointer itself never had rcu semantics.

The i915->gem.mmap_singleton is replaced in
file->f_op->release::singleton_release():

        static int singleton_release(struct inode *inode, struct file *file)
        {
                struct drm_i915_private *i915 = file->private_data;

                cmpxchg(&i915->gem.mmap_singleton, file, NULL);
                drm_dev_put(&i915->drm);

                return 0;
        }

The cmpxchg() is ordered against a concurrent update of
i915->gem.mmap_singleton from mmap_singleton(). IOW, when
mmap_singleton() fails to get a reference on i915->gem.mmap_singleton:

While mmap_singleton() does

        rcu_read_lock();
        file = get_file_rcu(&i915->gem.mmap_singleton);
        rcu_read_unlock();

it allocates a new file via anon_inode_getfile() and does

        smp_store_mb(i915->gem.mmap_singleton, file);

So, then what happens in the case of this bug is that at some point
fput() is called and drops the file->f_count to zero leaving the pointer
in i915->gem.mmap_singleton in tact.

Now, there might be delays until
file->f_op->release::singleton_release() is called and
i915->gem.mmap_singleton is set to NULL.

Say concurrently another task hits mmap_singleton() and does:

        rcu_read_lock();
        file = get_file_rcu(&i915->gem.mmap_singleton);
        rcu_read_unlock();

When get_file_rcu() fails to get a reference via atomic_inc_not_zero()
it will try the reload from i915->gem.mmap_singleton expecting it to be
NULL, assuming it has comparable semantics as we expect in
__fget_files_rcu().

But it hasn't so it reloads the same pointer again, trying the same
atomic_inc_not_zero() again and doing so until
file->f_op->release::singleton_release() of the old file has been
called.

So, in contrast to __fget_files_rcu() here we want to not retry when
atomic_inc_not_zero() has failed. We only want to retry in case we
managed to get a reference but the pointer did change on reload.

<3> [511.395679] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
<3> [511.395716] rcu:   Tasks blocked on level-1 rcu_node (CPUs 0-9): P6238
<3> [511.395934] rcu:   (detected by 16, t=65002 jiffies, g=123977, q=439 ncpus=20)
<6> [511.395944] task:i915_selftest   state:R  running task     stack:10568 pid:6238  tgid:6238  ppid:1001   flags:0x00004002
<6> [511.395962] Call Trace:
<6> [511.395966]  <TASK>
<6> [511.395974]  ? __schedule+0x3a8/0xd70
<6> [511.395995]  ? asm_sysvec_apic_timer_interrupt+0x1a/0x20
<6> [511.396003]  ? lockdep_hardirqs_on+0xc3/0x140
<6> [511.396013]  ? asm_sysvec_apic_timer_interrupt+0x1a/0x20
<6> [511.396029]  ? get_file_rcu+0x10/0x30
<6> [511.396039]  ? get_file_rcu+0x10/0x30
<6> [511.396046]  ? i915_gem_object_mmap+0xbc/0x450 [i915]
<6> [511.396509]  ? i915_gem_mmap+0x272/0x480 [i915]
<6> [511.396903]  ? mmap_region+0x253/0xb60
<6> [511.396925]  ? do_mmap+0x334/0x5c0
<6> [511.396939]  ? vm_mmap_pgoff+0x9f/0x1c0
<6> [511.396949]  ? rcu_is_watching+0x11/0x50
<6> [511.396962]  ? igt_mmap_offset+0xfc/0x110 [i915]
<6> [511.397376]  ? __igt_mmap+0xb3/0x570 [i915]
<6> [511.397762]  ? igt_mmap+0x11e/0x150 [i915]
<6> [511.398139]  ? __trace_bprintk+0x76/0x90
<6> [511.398156]  ? __i915_subtests+0xbf/0x240 [i915]
<6> [511.398586]  ? __pfx___i915_live_setup+0x10/0x10 [i915]
<6> [511.399001]  ? __pfx___i915_live_teardown+0x10/0x10 [i915]
<6> [511.399433]  ? __run_selftests+0xbc/0x1a0 [i915]
<6> [511.399875]  ? i915_live_selftests+0x4b/0x90 [i915]
<6> [511.400308]  ? i915_pci_probe+0x106/0x200 [i915]
<6> [511.400692]  ? pci_device_probe+0x95/0x120
<6> [511.400704]  ? really_probe+0x164/0x3c0
<6> [511.400715]  ? __pfx___driver_attach+0x10/0x10
<6> [511.400722]  ? __driver_probe_device+0x73/0x160
<6> [511.400731]  ? driver_probe_device+0x19/0xa0
<6> [511.400741]  ? __driver_attach+0xb6/0x180
<6> [511.400749]  ? __pfx___driver_attach+0x10/0x10
<6> [511.400756]  ? bus_for_each_dev+0x77/0xd0
<6> [511.400770]  ? bus_add_driver+0x114/0x210
<6> [511.400781]  ? driver_register+0x5b/0x110
<6> [511.400791]  ? i915_init+0x23/0xc0 [i915]
<6> [511.401153]  ? __pfx_i915_init+0x10/0x10 [i915]
<6> [511.401503]  ? do_one_initcall+0x57/0x270
<6> [511.401515]  ? rcu_is_watching+0x11/0x50
<6> [511.401521]  ? kmalloc_trace+0xa3/0xb0
<6> [511.401532]  ? do_init_module+0x5f/0x210
<6> [511.401544]  ? load_module+0x1d00/0x1f60
<6> [511.401581]  ? init_module_from_file+0x86/0xd0
<6> [511.401590]  ? init_module_from_file+0x86/0xd0
<6> [511.401613]  ? idempotent_init_module+0x17c/0x230
<6> [511.401639]  ? __x64_sys_finit_module+0x56/0xb0
<6> [511.401650]  ? do_syscall_64+0x3c/0x90
<6> [511.401659]  ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8
<6> [511.401684]  </TASK>

Link: [1]: https://lore.kernel.org/intel-gfx/SJ1PR11MB6129CB39EED831784C331BAFB9DEA@SJ1PR11MB6129.namprd11.prod.outlook.com
Link: [2]: https://intel-gfx-ci.01.org/tree/linux-next/next-20231013/bat-dg2-11/igt@i915_selftest@live@mman.html#dmesg-warnings10963
Cc: Jann Horn <jannh@google.com>,
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231025-formfrage-watscheln-84526cd3bd7d@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-25 22:17:04 +02:00
Max Kellermann
e4e8b47a34
fs: fix umask on NFS with CONFIG_FS_POSIX_ACL=n
Make IS_POSIXACL() return false if POSIX ACL support is disabled.

Never skip applying the umask in namei.c and never bother to do any
ACL specific checks if the filesystem falsely indicates it has ACLs
enabled when the feature is completely disabled in the kernel.

This fixes a problem where the umask is always ignored in the NFS
client when compiled without CONFIG_FS_POSIX_ACL.  This is a 4 year
old regression caused by commit 013cdf1088 which itself was not
completely wrong, but failed to consider all the side effects by
misdesigned VFS code.

Prior to that commit, there were two places where the umask could be
applied, for example when creating a directory:

 1. in the VFS layer in SYSCALL_DEFINE3(mkdirat), but only if
    !IS_POSIXACL()

 2. again (unconditionally) in nfs3_proc_mkdir()

The first one does not apply, because even without
CONFIG_FS_POSIX_ACL, the NFS client sets SB_POSIXACL in
nfs_fill_super().

After that commit, (2.) was replaced by:

 2b. in posix_acl_create(), called by nfs3_proc_mkdir()

There's one branch in posix_acl_create() which applies the umask;
however, without CONFIG_FS_POSIX_ACL, posix_acl_create() is an empty
dummy function which does not apply the umask.

The approach chosen by this patch is to make IS_POSIXACL() always
return false when POSIX ACL support is disabled, so the umask always
gets applied by the VFS layer.  This is consistent with the (regular)
behavior of posix_acl_create(): that function returns early if
IS_POSIXACL() is false, before applying the umask.

Therefore, posix_acl_create() is responsible for applying the umask if
there is ACL support enabled in the file system (SB_POSIXACL), and the
VFS layer is responsible for all other cases (no SB_POSIXACL or no
CONFIG_FS_POSIX_ACL).

Signed-off-by: Max Kellermann <mk@cm4all.com>
Link: https://lore.kernel.org/r/151603744662.29035.4910161264124875658.stgit@rabbit.intern.cm-ag
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:03:15 +02:00
Amir Goldstein
def3ae83da
fs: store real path instead of fake path in backing file f_path
A backing file struct stores two path's, one "real" path that is referring
to f_inode and one "fake" path, which should be displayed to users in
/proc/<pid>/maps.

There is a lot more potential code that needs to know the "real" path, then
code that needs to know the "fake" path.

Instead of code having to request the "real" path with file_real_path(),
store the "real" path in f_path and require code that needs to know the
"fake" path request it with file_user_path().
Replace the file_real_path() helper with a simple const accessor f_path().

After this change, file_dentry() is not expected to observe any files
with overlayfs f_path and real f_inode, so the call to ->d_real() should
not be needed.  Leave the ->d_real() call for now and add an assertion
in ovl_d_real() to catch if we made wrong assumptions.

Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Link: https://lore.kernel.org/r/CAJfpegtt48eXhhjDFA1ojcHPNKj3Go6joryCPtEFAKpocyBsnw@mail.gmail.com/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231009153712.1566422-4-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:03:15 +02:00
Amir Goldstein
08582d678f
fs: create helper file_user_path() for user displayed mapped file path
Overlayfs uses backing files with "fake" overlayfs f_path and "real"
underlying f_inode, in order to use underlying inode aops for mapped
files and to display the overlayfs path in /proc/<pid>/maps.

In preparation for storing the overlayfs "fake" path instead of the
underlying "real" path in struct backing_file, define a noop helper
file_user_path() that returns f_path for now.

Use the new helper in procfs and kernel logs whenever a path of a
mapped file is displayed to users.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231009153712.1566422-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:03:15 +02:00
Christian Brauner
0ede61d858
file: convert to SLAB_TYPESAFE_BY_RCU
In recent discussions around some performance improvements in the file
handling area we discussed switching the file cache to rely on
SLAB_TYPESAFE_BY_RCU which allows us to get rid of call_rcu() based
freeing for files completely. This is a pretty sensitive change overall
but it might actually be worth doing.

The main downside is the subtlety. The other one is that we should
really wait for Jann's patch to land that enables KASAN to handle
SLAB_TYPESAFE_BY_RCU UAFs. Currently it doesn't but a patch for this
exists.

With SLAB_TYPESAFE_BY_RCU objects may be freed and reused multiple times
which requires a few changes. So it isn't sufficient anymore to just
acquire a reference to the file in question under rcu using
atomic_long_inc_not_zero() since the file might have already been
recycled and someone else might have bumped the reference.

In other words, callers might see reference count bumps from newer
users. For this reason it is necessary to verify that the pointer is the
same before and after the reference count increment. This pattern can be
seen in get_file_rcu() and __files_get_rcu().

In addition, it isn't possible to access or check fields in struct file
without first aqcuiring a reference on it. Not doing that was always
very dodgy and it was only usable for non-pointer data in struct file.
With SLAB_TYPESAFE_BY_RCU it is necessary that callers first acquire a
reference under rcu or they must hold the files_lock of the fdtable.
Failing to do either one of this is a bug.

Thanks to Jann for pointing out that we need to ensure memory ordering
between reallocations and pointer check by ensuring that all subsequent
loads have a dependency on the second load in get_file_rcu() and
providing a fixup that was folded into this patch.

Cc: Jann Horn <jannh@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:02:48 +02:00
Jeff Layton
5aa8fd9cea
fs: add a new SB_I_NOUMASK flag
SB_POSIXACL must be set when a filesystem supports POSIX ACLs, but NFSv4
also sets this flag to prevent the VFS from applying the umask on
newly-created files. NFSv4 doesn't support POSIX ACLs however, which
causes confusion when other subsystems try to test for them.

Add a new SB_I_NOUMASK flag that allows filesystems to opt-in to umask
stripping without advertising support for POSIX ACLs. Set the new flag
on NFSv4 instead of SB_POSIXACL.

Also, move mode_strip_umask to namei.h and convert init_mknod and
init_mkdir to use it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230911-acl-fix-v3-1-b25315333f6c@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:02:47 +02:00
Lorenzo Stoakes
e8e17ee90e mm: drop the assumption that VM_SHARED always implies writable
Patch series "permit write-sealed memfd read-only shared mappings", v4.

The man page for fcntl() describing memfd file seals states the following
about F_SEAL_WRITE:-

    Furthermore, trying to create new shared, writable memory-mappings via
    mmap(2) will also fail with EPERM.

With emphasis on 'writable'.  In turns out in fact that currently the
kernel simply disallows all new shared memory mappings for a memfd with
F_SEAL_WRITE applied, rendering this documentation inaccurate.

This matters because users are therefore unable to obtain a shared mapping
to a memfd after write sealing altogether, which limits their usefulness. 
This was reported in the discussion thread [1] originating from a bug
report [2].

This is a product of both using the struct address_space->i_mmap_writable
atomic counter to determine whether writing may be permitted, and the
kernel adjusting this counter when any VM_SHARED mapping is performed and
more generally implicitly assuming VM_SHARED implies writable.

It seems sensible that we should only update this mapping if VM_MAYWRITE
is specified, i.e.  whether it is possible that this mapping could at any
point be written to.

If we do so then all we need to do to permit write seals to function as
documented is to clear VM_MAYWRITE when mapping read-only.  It turns out
this functionality already exists for F_SEAL_FUTURE_WRITE - we can
therefore simply adapt this logic to do the same for F_SEAL_WRITE.

We then hit a chicken and egg situation in mmap_region() where the check
for VM_MAYWRITE occurs before we are able to clear this flag.  To work
around this, perform this check after we invoke call_mmap(), with careful
consideration of error paths.

Thanks to Andy Lutomirski for the suggestion!

[1]:https://lore.kernel.org/all/20230324133646.16101dfa666f253c4715d965@linux-foundation.org/
[2]:https://bugzilla.kernel.org/show_bug.cgi?id=217238


This patch (of 3):

There is a general assumption that VMAs with the VM_SHARED flag set are
writable.  If the VM_MAYWRITE flag is not set, then this is simply not the
case.

Update those checks which affect the struct address_space->i_mmap_writable
field to explicitly test for this by introducing
[vma_]is_shared_maywrite() helper functions.

This remains entirely conservative, as the lack of VM_MAYWRITE guarantees
that the VMA cannot be written to.

Link: https://lkml.kernel.org/r/cover.1697116581.git.lstoakes@gmail.com
Link: https://lkml.kernel.org/r/d978aefefa83ec42d18dfa964ad180dbcde34795.1697116581.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18 14:34:19 -07:00