Documentation/ABI/stable/sysfs-block states:
What: /sys/block/<disk>/queue/discard_granularity
[...]
A discard_granularity of 0 means that the device does not support
discard functionality.
but this got broken when sorting out the block limits updates. Fix this
by setting the discard_granularity limit to zero when the combined
max_discard_sectors is zero.
Fixes: 3c407dc723 ("block: default the discard granularity to sector size")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250731152228.873923-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The merging/splitting code and other queue limits checking depends on the
physical block size being a power-of-2, so enforce it.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20250729091448.1691334-3-john.g.garry@oracle.com
[axboe: add missing braces]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In blk_stack_limits(), we check that the t->chunk_sectors value is a
multiple of the t->physical_block_size value.
However, by finding the chunk_sectors value in bytes, we may overflow
the unsigned int which holds chunk_sectors, so change the check to be
based on sectors.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20250729091448.1691334-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For a device that does not advertize an optimal I/O size, the function
blk_apply_bdi_limits() defaults to an initial setting of the ra_pages
field of struct backing_dev_info to VM_READAHEAD_PAGES, that is, 128 KB.
This low I/O size value is far from being optimal for hard-disk devices:
when reading files from multiple contexts using buffered I/Os, the seek
overhead between the small read commands generated to read-ahead
multiple files will significantly limit the performance that can be
achieved.
This fact applies to all ATA devices as ATA does not define an optimal
I/O size and the SCSI SAT specification does not define a default value
to expose to the host.
Modify blk_apply_bdi_limits() to use a device max_sectors limit to
calculate the ra_pages field of struct backing_dev_info, when the device
is a rotational one (BLK_FEAT_ROTATIONAL feature is set). For a SCSI
disk, this defaults to 2560 KB, which significantly improve performance
for buffered reads. Using XFS and sequentially reading randomly selected
(large) files stored on a SATA HDD, the maximum throughput achieved with
8 readers reading files with 1MB buffered I/Os increases from 122 MB/s
to 167 MB/s (+36%). The improvement is even larger when reading files
using 128 KB buffered I/Os, with a throughput increasing from 57 MB/s to
165 MB/s (+189%).
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250616062856.1629897-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.17/block-20250728' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- MD pull request via Yu:
- call del_gendisk synchronously (Xiao)
- cleanup unused variable (John)
- cleanup workqueue flags (Ryo)
- fix faulty rdev can't be removed during resync (Qixing)
- NVMe pull request via Christoph:
- try PCIe function level reset on init failure (Keith Busch)
- log TLS handshake failures at error level (Maurizio Lombardi)
- pci-epf: do not complete commands twice if nvmet_req_init()
fails (Rick Wertenbroek)
- misc cleanups (Alok Tiwari)
- Removal of the pktcdvd driver
This has been more than a decade coming at this point, and some
recently revealed breakages that had it causing issues even for cases
where it isn't required made me re-pull the trigger on this one. It's
known broken and nobody has stepped up to maintain the code
- Series for ublk supporting batch commands, enabling the use of
multishot where appropriate
- Speed up ublk exit handling
- Fix for the two-stage elevator fixing which could leak data
- Convert NVMe to use the new IOVA based API
- Increase default max transfer size to something more reasonable
- Series fixing write operations on zoned DM devices
- Add tracepoints for zoned block device operations
- Prep series working towards improving blk-mq queue management in the
presence of isolated CPUs
- Don't allow updating of the block size of a loop device that is
currently under exclusively ownership/open
- Set chunk sectors from stacked device stripe size and use it for the
atomic write size limit
- Switch to folios in bcache read_super()
- Fix for CD-ROM MRW exit flush handling
- Various tweaks, fixes, and cleanups
* tag 'for-6.17/block-20250728' of git://git.kernel.dk/linux: (94 commits)
block: restore two stage elevator switch while running nr_hw_queue update
cdrom: Call cdrom_mrw_exit from cdrom_release function
sunvdc: Balance device refcount in vdc_port_mpgroup_check
nvme-pci: try function level reset on init failure
dm: split write BIOs on zone boundaries when zone append is not emulated
block: use chunk_sectors when evaluating stacked atomic write limits
dm-stripe: limit chunk_sectors to the stripe size
md/raid10: set chunk_sectors limit
md/raid0: set chunk_sectors limit
block: sanitize chunk_sectors for atomic write limits
ilog2: add max_pow_of_two_factor()
nvmet: pci-epf: Do not complete commands twice if nvmet_req_init() fails
nvme-tcp: log TLS handshake failures at error level
docs: nvme: fix grammar in nvme-pci-endpoint-target.rst
nvme: fix typo in status code constant for self-test in progress
nvmet: remove redundant assignment of error code in nvmet_ns_enable()
nvme: fix incorrect variable in io cqes error message
nvme: fix multiple spelling and grammar issues in host drivers
block: fix blk_zone_append_update_request_bio() kernel-doc
md/raid10: fix set but not used variable in sync_request_write()
...
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Merge tag 'vfs-6.17-rc1.integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs 'protection info' updates from Christian Brauner:
"This adds the new FS_IOC_GETLBMD_CAP ioctl() to query metadata and
protection info (PI) capabilities. This ioctl returns information
about the files integrity profile. This is useful for userspace
applications to understand a files end-to-end data protection support
and configure the I/O accordingly.
For now this interface is only supported by block devices. However the
design and placement of this ioctl in generic FS ioctl space allows us
to extend it to work over files as well. This maybe useful when
filesystems start supporting PI-aware layouts.
A new structure struct logical_block_metadata_cap is introduced, which
contains the following fields:
- lbmd_flags:
bitmask of logical block metadata capability flags
- lbmd_interval:
the amount of data described by each unit of logical block metadata
- lbmd_size:
size in bytes of the logical block metadata associated with each
interval
- lbmd_opaque_size:
size in bytes of the opaque block tag associated with each interval
- lbmd_opaque_offset:
offset in bytes of the opaque block tag within the logical block
metadata
- lbmd_pi_size:
size in bytes of the T10 PI tuple associated with each interval
- lbmd_pi_offset:
offset in bytes of T10 PI tuple within the logical block metadata
- lbmd_pi_guard_tag_type:
T10 PI guard tag type
- lbmd_pi_app_tag_size:
size in bytes of the T10 PI application tag
- lbmd_pi_ref_tag_size:
size in bytes of the T10 PI reference tag
- lbmd_pi_storage_tag_size:
size in bytes of the T10 PI storage tag
The internal logic to fetch the capability is encapsulated in a helper
function blk_get_meta_cap(), which uses the blk_integrity profile
associated with the device. The ioctl returns -EOPNOTSUPP, if
CONFIG_BLK_DEV_INTEGRITY is not enabled"
* tag 'vfs-6.17-rc1.integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
block: fix lbmd_guard_tag_type assignment in FS_IOC_GETLBMD_CAP
block: fix FS_IOC_GETLBMD_CAP parsing in blkdev_common_ioctl()
fs: add ioctl to query metadata and protection info capabilities
nvme: set pi_offset only when checksum type is not BLK_INTEGRITY_CSUM_NONE
block: introduce pi_tuple_size field in blk_integrity
block: rename tuple_size field in blk_integrity to metadata_size
The atomic write unit max value is limited by any stacked device stripe
size.
It is required that the atomic write unit is a power-of-2 factor of the
stripe size.
Currently we use io_min limit to hold the stripe size, and check for a
io_min <= SECTOR_SIZE when deciding if we have a striped stacked device.
Nilay reports that this causes a problem when the physical block size is
greater than SECTOR_SIZE [0].
Furthermore, io_min may be mutated when stacking devices, and this makes
it a poor candidate to hold the stripe size. Such an example (of when
io_min may change) would be when the io_min is less than the physical
block size.
Use chunk_sectors to hold the stripe size, which is more appropriate.
[0] https://lore.kernel.org/linux-block/888f3b1d-7817-4007-b3b3-1a2ea04df771@linux.ibm.com/T/#mecca17129f72811137d3c2f1e477634e77f06781
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Tested-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250711105258.3135198-7-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently we just ensure that a non-zero value in chunk_sectors aligns
with any atomic write boundary, as the blk boundary functionality uses
both these values.
However it is also improper to have atomic write unit max > chunk_sectors
(for non-zero chunk_sectors), as this would lead to splitting of atomic
write bios (which is disallowed).
Sanitize atomic write unit max against chunk_sectors to avoid any
potential problems.
Fixes: d00eea91de ("block: Add extra checks in blk_validate_atomic_write_limits()")
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250711105258.3135198-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Introduce a new pi_tuple_size field in struct blk_integrity to
explicitly represent the size (in bytes) of the protection information
(PI) tuple. This is a prep patch.
Add validation in blk_validate_integrity_limits() to ensure that
pi size matches the expected size for known checksum types and never
exceeds the pi_tuple_size.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/20250630090548.3317-3-anuj20.g@samsung.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The tuple_size field in blk_integrity currently represents the total
size of metadata associated with each data interval. To make the meaning
more explicit, rename tuple_size to metadata_size. This is a purely
mechanical rename with no functional changes.
Suggested-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/20250630090548.3317-2-anuj20.g@samsung.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Currently, disks primarily implement the write zeroes command (aka
REQ_OP_WRITE_ZEROES) through two mechanisms: the first involves
physically writing zeros to the disk media (e.g., HDDs), while the
second performs an unmap operation on the logical blocks, effectively
putting them into a deallocated state (e.g., SSDs). The first method is
generally slow, while the second method is typically very fast.
For example, on certain NVMe SSDs that support NVME_NS_DEAC, submitting
REQ_OP_WRITE_ZEROES requests with the NVME_WZ_DEAC bit can accelerate
the write zeros operation by placing disk blocks into a deallocated
state, which opportunistically avoids writing zeroes to media while
still guaranteeing that subsequent reads from the specified block range
will return zeroed data. This is a best-effort optimization, not a
mandatory requirement, some devices may partially fall back to writing
physical zeroes due to factors such as misalignment or being asked to
clear a block range smaller than the device's internal allocation unit.
Therefore, the speed of this operation is not guaranteed.
It is difficult to determine whether the storage device supports unmap
write zeroes operation. We cannot determine this by only querying
bdev_limits(bdev)->max_write_zeroes_sectors. Therefore, first, add a new
hardware queue limit parameters, max_hw_wzeroes_unmap_sectors, to
indicate whether a device supports this unmap write zeroes operation.
Then, add two new counterpart software queue limits,
max_wzeroes_unmap_sectors and max_user_wzeroes_unmap_sectors, which
allow users to disable this operation if the speed is very slow on some
sepcial devices.
Finally, for the stacked devices cases, initialize these two parameters
to UINT_MAX. This operation should be enabled by both the stacking
driver and all underlying devices.
Thanks to Martin K. Petersen for optimizing the documentation of the
write_zeroes_unmap sysfs interface.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/20250619111806.3546162-2-yi.zhang@huaweicloud.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The block layer bounce buffering support is unused now, remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250505081138.3435992-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When the user increased the read-ahead size through sysfs this value
currently get lost if the device is reprobe, including on a resume
from suspend.
As there is no hardware limitation for the read-ahead size there is
no real need to reset it or track a separate hardware limitation
like for max_sectors.
This restores the pre-atomic queue limit behavior in the sd driver as
sd did not use blk_queue_io_opt and thus never updated the read ahead
size to the value based of the optimal I/O, but changes behavior for
all other drivers. As the new behavior seems useful and sd is the
driver for which the readahead size tweaks are most useful that seems
like a worthwhile trade off.
Fixes: 804e498e04 ("sd: convert to the atomic queue limits API")
Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20250424082521.1967286-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There're few sysfs attributes in block layer which don't really need
acquiring q->sysfs_lock while accessing it. The reason being, reading/
writing a value from/to such attributes are either atomic or could be
easily protected using READ_ONCE()/WRITE_ONCE(). Moreover, sysfs
attributes are inherently protected with sysfs/kernfs internal locking.
So this change help segregate all existing sysfs attributes for which
we could avoid acquiring q->sysfs_lock. For all read-only attributes
we removed the q->sysfs_lock from show method of such attributes. In
case attribute is read/write then we removed the q->sysfs_lock from
both show and store methods of these attributes.
We audited all block sysfs attributes and found following list of
attributes which shouldn't require q->sysfs_lock protection:
1. io_poll:
Write to this attribute is ignored. So, we don't need q->sysfs_lock.
2. io_poll_delay:
Write to this attribute is NOP, so we don't need q->sysfs_lock.
3. io_timeout:
Write to this attribute updates q->rq_timeout and read of this
attribute returns the value stored in q->rq_timeout Moreover, the
q->rq_timeout is set only once when we init the queue (under blk_mq_
init_allocated_queue()) even before disk is added. So that means
that we don't need to protect it with q->sysfs_lock. As this
attribute is not directly correlated with anything else simply using
READ_ONCE/WRITE_ONCE should be enough.
4. nomerges:
Write to this attribute file updates two q->flags : QUEUE_FLAG_
NOMERGES and QUEUE_FLAG_NOXMERGES. These flags are accessed during
bio-merge which anyways doesn't run with q->sysfs_lock held.
Moreover, the q->flags are updated/accessed with bitops which are
atomic. So, protecting it with q->sysfs_lock is not necessary.
5. rq_affinity:
Write to this attribute file makes atomic updates to q->flags:
QUEUE_FLAG_SAME_COMP and QUEUE_FLAG_SAME_FORCE. These flags are
also accessed from blk_mq_complete_need_ipi() using test_bit macro.
As read/write to q->flags uses bitops which are atomic, protecting
it with q->stsys_lock is not necessary.
6. nr_zones:
Write to this attribute happens in the driver probe method (except
nvme) before disk is added and outside of q->sysfs_lock or any other
lock. Moreover nr_zones is defined as "unsigned int" and so reading
this attribute, even when it's simultaneously being updated on other
cpu, should not return torn value on any architecture supported by
linux. So we can avoid using q->sysfs_lock or any other lock/
protection while reading this attribute.
7. discard_zeroes_data:
Reading of this attribute always returns 0, so we don't require
holding q->sysfs_lock.
8. write_same_max_bytes
Reading of this attribute always returns 0, so we don't require
holding q->sysfs_lock.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Link: https://lore.kernel.org/r/20250304102551.2533767-4-nilay@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, BLK_INTEGRITY_NOGENERATE and BLK_INTEGRITY_NOVERIFY are not
explicitly set during integrity initialization. This can lead to
incorrect reporting of read_verify and write_generate sysfs values,
particularly when a device does not support integrity. Ensure that these
flags are correctly initialized by default.
Reported-by: M Nikhil <nikh1092@linux.ibm.com>
Link: https://lore.kernel.org/linux-block/f6130475-3ccd-45d2-abde-3ccceada0f0a@linux.ibm.com/
Fixes: 9f4aa46f2a ("block: invert the BLK_INTEGRITY_{GENERATE,VERIFY} flags")
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250305063033.1813-3-anuj20.g@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
queue_limits_stack_integrity() incorrectly sets
BLK_INTEGRITY_DEVICE_CAPABLE for a DM device even when none of its
underlying devices support integrity. This happens because the flag is
inherited unconditionally. Ensure that integrity capabilities are
correctly propagated only when the underlying devices actually support
integrity.
Reported-by: M Nikhil <nikh1092@linux.ibm.com>
Link: https://lore.kernel.org/linux-block/f6130475-3ccd-45d2-abde-3ccceada0f0a@linux.ibm.com/
Fixes: c6e56cf6b2 ("block: move integrity information into queue_limits")
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250305063033.1813-2-anuj20.g@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
None of the few drivers still using the legacy block layer bounce
buffering support integrity metadata. Explicitly mark the features as
incompatible and stop creating the slab and mempool for integrity
buffers for the bounce bio_set.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250225154449.422989-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Using PAGE_SIZE as a minimum expected DMA segment size in consideration
of devices which have a max DMA segment size of < 64k when used on 64k
PAGE_SIZE systems leads to devices not being able to probe such as
eMMC and Exynos UFS controller [0] [1] you can end up with a probe failure
as follows:
WARNING: CPU: 2 PID: 397 at block/blk-settings.c:339 blk_validate_limits+0x364/0x3c0
Ensure we use min(max_seg_size, seg_boundary_mask + 1) as the new min segment
size when max segment size is < PAGE_SIZE for 16k and 64k base page size systems.
If anyone need to backport this patch, the following commits are depended:
commit 6aeb4f8364 ("block: remove bio_add_pc_page")
commit 02ee5d69e3 ("block: remove blk_rq_bio_prep")
commit b7175e24d6 ("block: add a dma mapping iterator")
Link: https://lore.kernel.org/linux-block/20230612203314.17820-1-bvanassche@acm.org/ # [0]
Link: https://lore.kernel.org/linux-block/1d55e942-5150-de4c-3a02-c3d066f87028@acm.org/ # [1]
Cc: Yi Zhang <yi.zhang@redhat.com>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Keith Busch <kbusch@kernel.org>
Tested-by: Paul Bunyan <pbunyan@redhat.com>
Reviewed-by: Daniel Gomez <da.gomez@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250225022141.2154581-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When block drivers or the core block code perform allocations with a
frozen queue, this could try to recurse into the block device to
reclaim memory and deadlock. Thus all allocations done by a process
that froze a queue need to be done without __GFP_IO and __GFP_FS.
Instead of tying to track all of them down, force a noio scope as
part of freezing the queue.
Note that nvme is a bit of a mess here due to the non-owner freezes,
and they will be addressed separately.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250131120352.1315351-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently only stacked devices need to explicitly enable atomic writes by
setting BLK_FEAT_ATOMIC_WRITES_STACKED flag.
This does not work well for device mapper stacking devices, as there many
sets of limits are stacked and what is the 'bottom' and 'top' device can
swapped. This means that BLK_FEAT_ATOMIC_WRITES_STACKED needs to be set
for many queue limits, which is messy.
Generalize enabling atomic writes enabling by ensuring that all devices
must explicitly set a flag - that includes NVMe, SCSI sd, and md raid.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20250116170301.474130-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The current check in blk_stack_atomic_writes_limits() for a bottom device
supporting atomic writes is to verify that limit atomic_write_unit_min is
non-zero.
This would cause a problem for device mapper queue limits calculation. This
is because it uses a temporary queue_limits structure to stack the limits,
before finally commiting the limits update.
The value of atomic_write_unit_min for the temporary queue_limits
structure is never evaluated and so cannot be used, so use limit
atomic_write_hw_unit_min.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250109114000.2299896-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For stacking atomic writes, ensure that the start sector is aligned with
the device atomic write unit min and any boundary. Otherwise, we may
permit misaligned atomic writes.
Rework bdev_can_atomic_write() into a common helper to resuse the
alignment check. There also use atomic_write_hw_unit_min, which is more
proper (than atomic_write_unit_min).
Fixes: d7f36dc446 ("block: Support atomic writes limits for stacked devices")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250109114000.2299896-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper that freezes the queue, updates the queue limits and
unfreezes the queue and convert all open coded versions of that to the
new helper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250110054726.1499538-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
queue_limits_commit_update is the function that needs to operate on a
frozen queue, not queue_limits_start_update. Update the kerneldoc
comments to reflect that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20250110054726.1499538-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow stacked devices to support atomic writes by aggregating the minimum
capability of all bottom devices.
Flag BLK_FEAT_ATOMIC_WRITES_STACKED is set for stacked devices which
have been enabled to support atomic writes.
Some things to note on the implementation:
- For simplicity, all bottom devices must have same atomic write boundary
value (if any)
- The atomic write boundary must be a power-of-2 already, but this
restriction could be relaxed. Furthermore, it is now required that the
chunk sectors for a top device must be aligned with this boundary.
- If a bottom device atomic write unit min/max are not aligned with the
top device chunk sectors, the top device atomic write unit min/max are
reduced to a value which works for the chunk sectors.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is so far expected that the limits passed are valid.
In future atomic writes will be supported for stacked block devices, and
calculating the limits there will be complicated, so add extra sanity
checks to ensure that the values are always valid.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20241118105018.1870052-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
lim->discard_granularity is always at least SECTOR_SIZE, so drop the
pointless check for granularity less than SECTOR_SIZE.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241112092144.4059847-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There was a bug report [1] where the user got a warning alignment
inconsistency. The user has optimal I/O 16776704 (0xFFFE00) and physical
block size 4096. Note that the optimal I/O size may be set by the DMA
engines or SCSI controllers and they have no knowledge about the disks
attached to them, so the situation with optimal I/O not aligned to
physical block size may happen.
This commit makes blk_validate_limits round down optimal I/O size to the
physical block size of the block device.
Closes: https://lore.kernel.org/dm-devel/1426ad71-79b4-4062-b2bf-84278be66a5d@redhat.com/T/ [1]
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: a23634644a ("block: take io_opt and io_min into account for max_sectors")
Cc: stable@vger.kernel.org # v6.11+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/3dc0014b-9690-dc38-81c9-4a316a2d4fb2@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While block drivers do the validation as part of committing them to the
queue, users that use the limit outside of a block device context have
to validate the limits and fill in the calculated values as well.
So far btrfs is the only user of queue limits without a block device,
and it has gotten away with that more or less by accident. But with
commit 559218d43e ("block: pre-calculate max_zone_append_sectors")
this became fatal for setups that have small max zone append size,
as it won't be limited now.
Export blk_validate_limits so that it can be called directly from btrfs.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241113084541.34315-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
max_zone_append_sectors differs from all other queue limits in that the
final value used is not stored in the queue_limits but needs to be
obtained using queue_limits_max_zone_append_sectors helper. This not
only adds (tiny) extra overhead to the I/O path, but also can be easily
forgotten in file system code.
Add a new max_hw_zone_append_sectors value to queue_limits which is
set by the driver, and calculate max_zone_append_sectors from that and
the other inputs in blk_validate_zoned_limits, similar to how
max_sectors is calculated to fix this.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241104073955.112324-3-hch@lst.de
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20241108154657.845768-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
max_zone_append_sectors differs from all other queue limits in that the
final value used is not stored in the queue_limits but needs to be
obtained using queue_limits_max_zone_append_sectors helper. This not
only adds (tiny) extra overhead to the I/O path, but also can be easily
forgotten in file system code.
Add a new max_hw_zone_append_sectors value to queue_limits which is
set by the driver, and calculate max_zone_append_sectors from that and
the other inputs in blk_validate_zoned_limits, similar to how
max_sectors is calculated to fix this.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241104073955.112324-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Listing every single features that needs to be pre-set by stacking
drivers does not scale.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241104054218.45596-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to get the queue_limits from the bdev without having to
poke into the request_queue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241029141937.249920-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_limits_io_min and blk_limits_io_opt are unused since the
recent commit
0a94a469a4 ("dm: stop using blk_limits_io_{min,opt}")
Remove them.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20240920004817.676216-1-linux@treblig.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some drivers validate that their own logical block size. It is no harm to
always do this, so validate in blk_validate_limits().
This allows us to remove the validation in most of those drivers.
Add a comment to blk_validate_block_size() to inform users that self-
validation of LBS is usually unnecessary.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240708091651.177447-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't reduce the max_sectors value below the normal cap when the driver
advertsizes a very low io_opt. This restores the behavior we had before
the recent changes to the max_sectors calculation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240701051800.1245240-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If io_min is larger than the cap, it must by definition be non-zero.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240701051800.1245240-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
dma_pad_mask is a queue_limits by all ways of looking at it, so move it
there and set it through the atomic queue limits APIs.
Add a little helper that takes the alignment and pad into account to
simplify the code that is touched a bit.
Note that there never was any need for the > check in
blk_queue_update_dma_pad, this probably was just copy and paste from
dma_update_dma_alignment.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240626142637.300624-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Mark blk_apply_bdi_limits non-static and open code disk_update_readahead
in the only caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240626142637.300624-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
"static" never goes on a line of its own.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240626142637.300624-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is a flag for ->flags and not a feature for ->features. And fix the
one place that actually incorrectly cleared it from ->features.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240626142637.300624-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For arm32, we get the following build warning:
In file included from /tmp/next/build/include/linux/printk.h:10,
from /tmp/next/build/include/linux/kernel.h:31,
from /tmp/next/build/block/blk-settings.c:5:
/tmp/next/build/block/blk-settings.c: In function 'blk_validate_atomic_write_limits':
/tmp/next/build/include/asm-generic/div64.h:222:35: warning: comparison of distinct pointer types lacks a cast
222 | (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
| ^~
The divident for do_div() should be 64b, which it is not. Since we want to
check 2x unsigned ints, just use % operator. This allows us to drop the
chunk_sectors variable.
Fixes: 9da3d1e912 ("block: Add core atomic write support")
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/linux-next/b765d200-4e0f-48b1-a962-7dfa1c4aef9c@kernel.dk/T/#mbf067b1edd89c7f9d7dac6e258c516199953a108
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20240621183016.3092518-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add atomic write support, as follows:
- add helper functions to get request_queue atomic write limits
- report request_queue atomic write support limits to sysfs and update Doc
- support to safely merge atomic writes
- deal with splitting atomic writes
- misc helper functions
- add a per-request atomic write flag
New request_queue limits are added, as follows:
- atomic_write_hw_max is set by the block driver and is the maximum length
of an atomic write which the device may support. It is not
necessarily a power-of-2.
- atomic_write_max_sectors is derived from atomic_write_hw_max_sectors and
max_hw_sectors. It is always a power-of-2. Atomic writes may be merged,
and atomic_write_max_sectors would be the limit on a merged atomic write
request size. This value is not capped at max_sectors, as the value in
max_sectors can be controlled from userspace, and it would only cause
trouble if userspace could limit atomic_write_unit_max_bytes and the
other atomic write limits.
- atomic_write_hw_unit_{min,max} are set by the block driver and are the
min/max length of an atomic write unit which the device may support. They
both must be a power-of-2. Typically atomic_write_hw_unit_max will hold
the same value as atomic_write_hw_max.
- atomic_write_unit_{min,max} are derived from
atomic_write_hw_unit_{min,max}, max_hw_sectors, and block core limits.
Both min and max values must be a power-of-2.
- atomic_write_hw_boundary is set by the block driver. If non-zero, it
indicates an LBA space boundary at which an atomic write straddles no
longer is atomically executed by the disk. The value must be a
power-of-2. Note that it would be acceptable to enforce a rule that
atomic_write_hw_boundary_sectors is a multiple of
atomic_write_hw_unit_max, but the resultant code would be more
complicated.
All atomic writes limits are by default set 0 to indicate no atomic write
support. Even though it is assumed by Linux that a logical block can always
be atomically written, we ignore this as it is not of particular interest.
Stacked devices are just not supported either for now.
An atomic write must always be submitted to the block driver as part of a
single request. As such, only a single BIO must be submitted to the block
layer for an atomic write. When a single atomic write BIO is submitted, it
cannot be split. As such, atomic_write_unit_{max, min}_bytes are limited
by the maximum guaranteed BIO size which will not be required to be split.
This max size is calculated by request_queue max segments and the number
of bvecs a BIO can fit, BIO_MAX_VECS. Currently we rely on userspace
issuing a write with iovcnt=1 for pwritev2() - as such, we can rely on each
segment containing PAGE_SIZE of data, apart from the first+last, which each
can fit logical block size of data. The first+last will be LBS
length/aligned as we rely on direct IO alignment rules also.
New sysfs files are added to report the following atomic write limits:
- atomic_write_unit_max_bytes - same as atomic_write_unit_max_sectors in
bytes
- atomic_write_unit_min_bytes - same as atomic_write_unit_min_sectors in
bytes
- atomic_write_boundary_bytes - same as atomic_write_hw_boundary_sectors in
bytes
- atomic_write_max_bytes - same as atomic_write_max_sectors in bytes
Atomic writes may only be merged with other atomic writes and only under
the following conditions:
- total resultant request length <= atomic_write_max_bytes
- the merged write does not straddle a boundary
Helper function bdev_can_atomic_write() is added to indicate whether
atomic writes may be issued to a bdev. If a bdev is a partition, the
partition start must be aligned with both atomic_write_unit_min_sectors
and atomic_write_hw_boundary_sectors.
FSes will rely on the block layer to validate that an atomic write BIO
submitted will be of valid size, so add blk_validate_atomic_write_op_size()
for this purpose. Userspace expects an atomic write which is of invalid
size to be rejected with -EINVAL, so add BLK_STS_INVAL for this. Also use
BLK_STS_INVAL for when a BIO needs to be split, as this should mean an
invalid size BIO.
Flag REQ_ATOMIC is used for indicating an atomic write.
Co-developed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20240620125359.2684798-6-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge in queue limits cleanups.
* for-6.11/block-limits:
block: move the raid_partial_stripes_expensive flag into the features field
block: remove the discard_alignment flag
block: move the misaligned flag into the features field
block: renumber and rename the cache disabled flag
block: fix spelling and grammar for in writeback_cache_control.rst
block: remove the unused blk_bounce enum
Move the raid_partial_stripes_expensive flags into the features field to
reclaim a little bit of space.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240619154623.450048-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
queue_limits.discard_alignment is never read except in the places
where it is stacked into another limit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240619154623.450048-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the misaligned flags into the features field to reclaim a little
bit of space.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240619154623.450048-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge in last round of queue limits changes from Christoph.
* for-6.11/block-limits: (26 commits)
block: move the bounce flag into the features field
block: move the skip_tagset_quiesce flag to queue_limits
block: move the pci_p2pdma flag to queue_limits
block: move the zone_resetall flag to queue_limits
block: move the zoned flag into the features field
block: move the poll flag to queue_limits
block: move the dax flag to queue_limits
block: move the nowait flag to queue_limits
block: move the synchronous flag to queue_limits
block: move the stable_writes flag to queue_limits
block: move the io_stat flag setting to queue_limits
block: move the add_random flag to queue_limits
block: move the nonrot flag to queue_limits
block: move cache control settings out of queue->flags
block: remove blk_flush_policy
block: freeze the queue in queue_attr_store
nbd: move setting the cache control flags to __nbd_set_size
virtio_blk: remove virtblk_update_cache_mode
loop: fold loop_update_rotational into loop_reconfigure_limits
loop: also use the default block size from an underlying block device
...
Signed-off-by: Jens Axboe <axboe@kernel.dk>
