Commit Graph

160 Commits

Author SHA1 Message Date
Chao Yu
df0ce6cefa erofs: support to readahead dirent blocks in erofs_readdir()
This patch supports to readahead more blocks in erofs_readdir(), it can
enhance readdir performance in large direcotry.

readdir test in a large directory which contains 12000 sub-files.

		files_per_second
Before:		926385.54
After:		2380435.562

Meanwhile, let's introduces a new sysfs entry to control readahead
bytes to provide more flexible policy for readahead of readdir().
- location: /sys/fs/erofs/<disk>/dir_ra_bytes
- default value: 16384
- disable readahead: set the value to 0

Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250721021352.2495371-1-chao@kernel.org
[ Gao Xiang: minor styling adjustment. ]
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2025-07-24 19:44:08 +08:00
Bo Liu (OpenAnolis)
414091322c erofs: implement metadata compression
Thanks to the meta buffer infrastructure, metadata-compressed inodes are
just read from the metabox inode instead of the blockdevice (or backing
file) inode.

The same is true for shared extended attributes.

When metadata compression is enabled, inode numbers are divided from
on-disk NIDs because of non-LTS 32-bit application compatibility.

Co-developed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Bo Liu (OpenAnolis) <liubo03@inspur.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250722003229.2121752-1-hsiangkao@linux.alibaba.com
2025-07-24 19:43:31 +08:00
Gao Xiang
681acbda3a erofs: add on-disk definition for metadata compression
Filesystem metadata has a high degree of redundancy, so it should
compress well in the general case.

Although metadata compression can increase overall I/O latency, many
users care more about minimized image sizes than extreme runtime
performance.  Let's implement metadata compression in response to user
requests [1].

Actually, it's quite simple to implement metadata compression: since
EROFS already supports per-inode compression, we can simply treat a
special inode (called `the metabox inode`) as a container for compressed
inode metadata.  Since EROFS supports multiple algorithms, users can
even specify LZ4 for metadata and LZMA for data.

To better support incremental builds, the MSB of NIDs indicates where
the inode metadata is located: if bit 63 is set, the inode itself should
be read from `the metabox inode`.

Optionally, shared xattrs can also be kept in `the metabox inode` if
COMPAT_SHARED_EA_IN_METABOX is set.

[1] https://issues.redhat.com/browse/RHEL-75783

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250717070804.1446345-2-hsiangkao@linux.alibaba.com
2025-07-24 19:43:24 +08:00
Gao Xiang
5e744cb615 erofs: remove need_kmap in erofs_read_metabuf()
- need_kmap is always true except for a ztailpacking case; thus, just
   open-code that one;

 - The upcoming metadata compression will add a new boolean, so simplify
   this first.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250714090907.4095645-1-hsiangkao@linux.alibaba.com
2025-07-24 19:42:05 +08:00
Gao Xiang
b44686c839 erofs: fix large fragment handling
Fragments aren't limited by Z_EROFS_PCLUSTER_MAX_DSIZE. However, if
a fragment's logical length is larger than Z_EROFS_PCLUSTER_MAX_DSIZE
but the fragment is not the whole inode, it currently returns
-EOPNOTSUPP because m_flags has the wrong EROFS_MAP_ENCODED flag set.
It is not intended by design but should be rare, as it can only be
reproduced by mkfs with `-Eall-fragments` in a specific case.

Let's normalize fragment m_flags using the new EROFS_MAP_FRAGMENT.

Reported-by: Axel Fontaine <axel@axelfontaine.com>
Closes: https://github.com/erofs/erofs-utils/issues/23
Fixes: 7c3ca1838a ("erofs: restrict pcluster size limitations")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250711195826.3601157-1-hsiangkao@linux.alibaba.com
2025-07-12 04:02:44 +08:00
Gao Xiang
27917e8194 erofs: address D-cache aliasing
Flush the D-cache before unlocking folios for compressed inodes, as
they are dirtied during decompression.

Avoid calling flush_dcache_folio() on every CPU write, since it's more
like playing whack-a-mole without real benefit.

It has no impact on x86 and arm64/risc-v: on x86, flush_dcache_folio()
is a no-op, and on arm64/risc-v, PG_dcache_clean (PG_arch_1) is clear
for new page cache folios.  However, certain ARM boards are affected,
as reported.

Fixes: 3883a79abd ("staging: erofs: introduce VLE decompression support")
Closes: https://lore.kernel.org/r/c1e51e16-6cc6-49d0-a63e-4e9ff6c4dd53@pengutronix.de
Closes: https://lore.kernel.org/r/38d43fae-1182-4155-9c5b-ffc7382d9917@siemens.com
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250709034614.2780117-2-hsiangkao@linux.alibaba.com
2025-07-10 17:08:27 +08:00
Sheng Yong
c36ec00d7f erofs: add 'fsoffset' mount option to specify filesystem offset
When attempting to use an archive file, such as APEX on android,
as a file-backed mount source, it fails because EROFS image within
the archive file does not start at offset 0. As a result, a loop
or a dm device is still needed to attach the image file at an
appropriate offset first. Similarly, if an EROFS image within a
block device does not start at offset 0, it cannot be mounted
directly either.

To address this issue, this patch adds a new mount option `fsoffset=x'
to accept a start offset for the primary device. The offset should be
aligned to the block size. EROFS will add this offset before performing
read requests.

Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Signed-off-by: Wang Shuai <wangshuai12@xiaomi.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250517090544.2687651-1-shengyong1@xiaomi.com
[ Gao Xiang: minor update on documentation and the error message. ]
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2025-05-22 11:57:57 +08:00
Gao Xiang
1d191b4ca5 erofs: implement encoded extent metadata
Implement the extent metadata parsing described in the previous commit.
For 16-byte and 32-byte extent records, currently it is just a trivial
binary search without considering the last access footprint, but it can
be optimized for better sequential performance later.

Tail fragments are supported, but ztailpacking feature is not
for simplicity.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095459.2620647-9-hsiangkao@linux.alibaba.com
2025-03-17 14:02:15 +08:00
Gao Xiang
efb2aef569 erofs: add encoded extent on-disk definition
Previously, EROFS provided both (non-)compact compressed indexes to
keep necessary hints for each logical block, enabling O(1) random
indexing.  This approach was originally designed for small compression
units (e.g., 4KiB), where compressed data is strictly block-aligned via
fixed-sized output compression.

However, EROFS now supports big pclusters up to 1MiB and many users use
large configurations to minimize image sizes.  For such configurations,
the total number of extents decreases significantly (e.g., only 1,024
extents for a 1GiB file using 1MiB pclusters), then runtime metadata
overhead becomes negligible compared to data I/O and decoding costs.

Additionally, some popular compression algorithm (mainly Zstd) still
lacks native fixed-sized output compression support (although it's
planned by their authors).  Instead of just waiting for compressor
improvements, let's adopt byte-oriented extents, allowing these
compressors to retain their current methods.

For example, it speeds up Zstd compression a lot:
Processor: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz * 96
Dataset:   enwik9
Build time Size       Type Command Line
3m52.339s  266653696  FO   -C524288 -zzstd,22
3m48.549s  266174464  FO   -E48bit -C524288 -zzstd,22
0m12.821s  272134144  FI   -E48bit -C1048576 --max-extent-bytes=1048576 -zzstd,22

0m14.528s  248987648  FO   -C1048576 -zlzma,9
0m14.605s  248504320  FO   -E48bit -C1048576 -zlzma,9

Encoded extents are structured as an array of `struct z_erofs_extent`,
sorted by logical address in ascending order:
   __le32 plen       // encoded length, algorithm id and flags
   __le32 pstart_lo  // physical offset LSB
   __le32 pstart_hi  // physical offset MSB
   __le32 lstart_lo  // logical offset
   __le32 lstart_hi  // logical offset MSB
   ..

Note that prefixed reduced records can be used to minimize metadata for
specific cases (e.g. lstart less than 32 bits, then 32 to 16 bytes).

If the logical lengths of all encoded extents are the same, 4-byte
(plen) and 8-byte (plen, pstart_lo) records can be used. Or, 16-byte
(plen .. lstart_lo) and 32-byte full records have to be used instead.

If 16-byte and 32-byte records are used, the total number of extents
is kept in `struct z_erofs_map_header`, and binary search can be
applied on them.  Note that `eytzinger order` is not considerd because
data sequential access is important.

If 4-byte records are used, 8-byte start physical offset is between
`struct z_erofs_map_header` and the `plen` array.

In addition, 64-bit physical offsets can be applied with new encoded
extent format to match full 48-bit block addressing.

Remove redundant comments around `struct z_erofs_lcluster_index` too.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095459.2620647-8-hsiangkao@linux.alibaba.com
2025-03-17 14:02:15 +08:00
Gao Xiang
fe1e57d44d erofs: initialize decompression early
- Rename erofs_init_managed_cache() to z_erofs_init_super();
 - Move the initialization of managed_pslots into z_erofs_init_super() too;
 - Move z_erofs_init_super() and packed inode preparation upwards, before
   the root inode initialization.

Therefore, the root directory can also be compressible.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250317054840.3483000-1-hsiangkao@linux.alibaba.com
2025-03-17 14:02:08 +08:00
Gao Xiang
e9dfe33aea erofs: support dot-omitted directories
There's no need to record "." dirents in the directory data (while
they could be used for sanity checks, they aren't very useful.)
Omitting "." dirents also improves directory data deduplication.

Use a per-inode (instead of per-sb) flag to indicate if the "." dirent
is omitted or not, ensuring compatibility with incremental builds.  It
also reuses EROFS_I_NLINK_1_BIT, as it has very limited use cases for
directories with `nlink = 1`.

Emit the "." entry as the last virtual dirent in the directory because
it is _much_ less frequently used than the ".." dirent.  It also keeps
`f_pos` meaningful, as it strictly follows the directory data when it's
less than i_size.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095459.2620647-6-hsiangkao@linux.alibaba.com
2025-03-17 01:25:32 +08:00
Gao Xiang
2e1473d519 erofs: implement 48-bit block addressing for unencoded inodes
It adapts the on-disk changes from the previous commit.  It also
supports EROFS_NULL_ADDR (all 1's) for EROFS_INODE_FLAT_PLAIN inodes
to indicate 0-filled inodes, as it's common for composefs use cases.
As a result, EROFS_INODE_CHUNK_BASED is no longer needed.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095459.2620647-5-hsiangkao@linux.alibaba.com
2025-03-17 01:25:26 +08:00
Gao Xiang
61ba89b579 erofs: add 48-bit block addressing on-disk support
The current 32-bit block addressing limits EROFS to a 16TiB maximum
volume size with 4KiB blocks.  However, several new use cases now
require larger capacity support:
 - Massive datasets for model training in order to boost random
   sampling performance for each epoch;

 - Object storage clients using EROFS direct passthrough.

This extends core on-disk structures to support 48-bit block addressing,
such as inodes, device slots, and inode chunks.

Additionally:
 - Expand superblock root NID to 8-byte `rootnid_8b` to enable full
   out-of-place update incremental builds;

 - Introduce `epoch` field in the superblock as well as add `mtime`
   field to 32-byte compact inodes for basic timestamp support.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Acked-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250310095459.2620647-4-hsiangkao@linux.alibaba.com
2025-03-17 01:23:25 +08:00
Gao Xiang
b7710262d7 erofs: simplify tail inline pcluster handling
Use `z_idata_size != 0` to indicate that ztailpacking is enabled.
`Z_EROFS_ADVISE_INLINE_PCLUSTER` cannot be ignored, as `h_idata_size`
could be non-zero prior to erofs-utils 1.6 [1].

Additionally, merge `z_idataoff` and `z_fragmentoff` since these two
features are mutually exclusive for a given inode.

[1] https://git.kernel.org/xiang/erofs-utils/c/547bea3cb71a
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250225114038.3259726-1-hsiangkao@linux.alibaba.com
2025-03-17 01:22:18 +08:00
Gao Xiang
5794502777 erofs: allow 16-byte volume name again
Actually, volume name doesn't need to include the NIL terminator if
the string length matches the on-disk field size as mentioned in [1].

I tend to relax it together with the upcoming 48-bit block addressing
(or stable kernels which backport this fix) so that we could have a
chance to record a 16-byte volume name like ext4.

Since in-memory `volume_name` has no user, just get rid of the unneeded
check for now.  `sbi->uuid` is useless and avoid it too.

[1] https://lore.kernel.org/r/96efe46b-dcce-4490-bba1-a0b00932d1cc@linux.alibaba.com

Fixes: a64d9493f5 ("staging: erofs: refuse to mount images with malformed volume name")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250225033934.2542635-1-hsiangkao@linux.alibaba.com
2025-03-17 01:21:36 +08:00
Bo Liu
706e50e46a erofs: get rid of erofs_kmap_type
Since EROFS_KMAP_ATOMIC is no longer valid, get rid of erofs_kmap_type too.

Signed-off-by: Bo Liu <liubo03@inspur.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20250217093141.2659-1-liubo03@inspur.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2025-03-17 01:21:24 +08:00
Gao Xiang
6422cde1b0 erofs: use buffered I/O for file-backed mounts by default
For many use cases (e.g. container images are just fetched from remote),
performance will be impacted if underlay page cache is up-to-date but
direct i/o flushes dirty pages first.

Instead, let's use buffered I/O by default to keep in sync with loop
devices and add a (re)mount option to explicitly give a try to use
direct I/O if supported by the underlying files.

The container startup time is improved as below:
[workload] docker.io/library/workpress:latest
                                     unpack        1st run  non-1st runs
EROFS snapshotter buffered I/O file  4.586404265s  0.308s   0.198s
EROFS snapshotter direct I/O file    4.581742849s  2.238s   0.222s
EROFS snapshotter loop               4.596023152s  0.346s   0.201s
Overlayfs snapshotter                5.382851037s  0.206s   0.214s

Fixes: fb17675026 ("erofs: add file-backed mount support")
Cc: Derek McGowan <derek@mcg.dev>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241212134336.2059899-1-hsiangkao@linux.alibaba.com
2024-12-16 21:02:07 +08:00
Gao Xiang
f8d920a402 erofs: reference struct erofs_device_info for erofs_map_dev
Record `m_sb` and `m_dif` to replace `m_fscache`, `m_daxdev`, `m_fp`
and `m_dax_part_off` in order to simplify the codebase.

Note that `m_bdev` is still left since it can be assigned from
`sb->s_bdev` directly.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241212235401.2857246-1-hsiangkao@linux.alibaba.com
2024-12-16 21:02:06 +08:00
Gao Xiang
7b00af2c54 erofs: use struct erofs_device_info for the primary device
Instead of just listing each one directly in `struct erofs_sb_info`
except that we still use `sb->s_bdev` for the primary block device.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241216125310.930933-2-hsiangkao@linux.alibaba.com
2024-12-16 21:01:59 +08:00
Gao Xiang
ec4f59d1a9 erofs: get rid of buf->kmap_type
After commit 927e5010ff ("erofs: use kmap_local_page() only for
erofs_bread()"), `buf->kmap_type` actually has no use at all.

Let's get rid of `buf->kmap_type` now.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241114095813.839866-1-hsiangkao@linux.alibaba.com
2024-11-18 18:50:14 +08:00
Gao Xiang
3a23787ca8 erofs: fix file-backed mounts over FUSE
syzbot reported a null-ptr-deref in fuse_read_args_fill:
 fuse_read_folio+0xb0/0x100 fs/fuse/file.c:905
 filemap_read_folio+0xc6/0x2a0 mm/filemap.c:2367
 do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3825
 read_mapping_folio include/linux/pagemap.h:1011 [inline]
 erofs_bread+0x34d/0x7e0 fs/erofs/data.c:41
 erofs_read_superblock fs/erofs/super.c:281 [inline]
 erofs_fc_fill_super+0x2b9/0x2500 fs/erofs/super.c:625

Unlike most filesystems, some network filesystems and FUSE need
unavoidable valid `file` pointers for their read I/Os [1].
Anyway, those use cases need to be supported too.

[1] https://docs.kernel.org/filesystems/vfs.html

Reported-by: syzbot+0b1279812c46e48bb0c1@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/6727bbdf.050a0220.3c8d68.0a7e.GAE@google.com
Fixes: fb17675026 ("erofs: add file-backed mount support")
Tested-by: syzbot+0b1279812c46e48bb0c1@syzkaller.appspotmail.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241114234905.1873723-1-hsiangkao@linux.alibaba.com
2024-11-18 18:50:13 +08:00
Gou Hao
90655ee279 erofs: simplify definition of the log functions
Use printk instead of pr_info/err to reduce
redundant code.

Signed-off-by: Gou Hao <gouhao@uniontech.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241114013247.30821-1-gouhao@uniontech.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-11-18 18:50:13 +08:00
Chunhai Guo
db80b98305 erofs: add sysfs node to drop internal caches
Add a sysfs node to drop compression-related caches, currently used to
drop in-memory pclusters and cached compressed folios.

Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241113041148.749129-1-guochunhai@vivo.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-11-18 18:50:13 +08:00
Gao Xiang
bf1aa03980 erofs: sunset struct erofs_workgroup
`struct erofs_workgroup` was introduced to provide a unique header
for all physically indexed objects.  However, after big pclusters and
shared pclusters are implemented upstream, it seems that all EROFS
encoded data (which requires transformation) can be represented with
`struct z_erofs_pcluster` directly.

Move all members into `struct z_erofs_pcluster` for simplicity.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241021035323.3280682-3-hsiangkao@linux.alibaba.com
2024-11-18 18:50:12 +08:00
Gao Xiang
9c91f95962 erofs: move erofs_workgroup operations into zdata.c
Move related helpers into zdata.c as an intermediate step of getting
rid of `struct erofs_workgroup`, and rename:

 erofs_workgroup_put => z_erofs_put_pcluster
 erofs_workgroup_get => z_erofs_get_pcluster
 erofs_try_to_release_workgroup => erofs_try_to_release_pcluster
 erofs_shrink_workstation => z_erofs_shrink_scan

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241021035323.3280682-2-hsiangkao@linux.alibaba.com
2024-11-18 18:50:12 +08:00
Gao Xiang
b091e8ed24 erofs: get rid of erofs_{find,insert}_workgroup
Just fold them into the only two callers since
they are simple enough.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241021035323.3280682-1-hsiangkao@linux.alibaba.com
2024-11-18 18:50:03 +08:00
Gao Xiang
283213718f erofs: support compressed inodes for fileio
Use pseudo bios just like the previous fscache approach since
merged bio_vecs can be filled properly with unique interfaces.

Reviewed-by: Sandeep Dhavale <dhavale@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240830032840.3783206-3-hsiangkao@linux.alibaba.com
2024-09-10 15:27:09 +08:00
Gao Xiang
ce63cb62d7 erofs: support unencoded inodes for fileio
Since EROFS only needs to handle read requests in simple contexts,
Just directly use vfs_iocb_iter_read() for data I/Os.

Reviewed-by: Sandeep Dhavale <dhavale@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240905093031.2745929-1-hsiangkao@linux.alibaba.com
2024-09-10 15:26:36 +08:00
Gao Xiang
fb17675026 erofs: add file-backed mount support
It actually has been around for years: For containers and other sandbox
use cases, there will be thousands (and even more) of authenticated
(sub)images running on the same host, unlike OS images.

Of course, all scenarios can use the same EROFS on-disk format, but
bdev-backed mounts just work well for OS images since golden data is
dumped into real block devices.  However, it's somewhat hard for
container runtimes to manage and isolate so many unnecessary virtual
block devices safely and efficiently [1]: they just look like a burden
to orchestrators and file-backed mounts are preferred indeed.  There
were already enough attempts such as Incremental FS, the original
ComposeFS and PuzzleFS acting in the same way for immutable fses.  As
for current EROFS users, ComposeFS, containerd and Android APEXs will
be directly benefited from it.

On the other hand, previous experimental feature "erofs over fscache"
was once also intended to provide a similar solution (inspired by
Incremental FS discussion [2]), but the following facts show file-backed
mounts will be a better approach:
 - Fscache infrastructure has recently been moved into new Netfslib
   which is an unexpected dependency to EROFS really, although it
   originally claims "it could be used for caching other things such as
   ISO9660 filesystems too." [3]

 - It takes an unexpectedly long time to upstream Fscache/Cachefiles
   enhancements.  For example, the failover feature took more than
   one year, and the deamonless feature is still far behind now;

 - Ongoing HSM "fanotify pre-content hooks" [4] together with this will
   perfectly supersede "erofs over fscache" in a simpler way since
   developers (mainly containerd folks) could leverage their existing
   caching mechanism entirely in userspace instead of strictly following
   the predefined in-kernel caching tree hierarchy.

After "fanotify pre-content hooks" lands upstream to provide the same
functionality, "erofs over fscache" will be removed then (as an EROFS
internal improvement and EROFS will not have to bother with on-demand
fetching and/or caching improvements anymore.)

[1] https://github.com/containers/storage/pull/2039
[2] https://lore.kernel.org/r/CAOQ4uxjbVxnubaPjVaGYiSwoGDTdpWbB=w_AeM6YM=zVixsUfQ@mail.gmail.com
[3] https://docs.kernel.org/filesystems/caching/fscache.html
[4] https://lore.kernel.org/r/cover.1723670362.git.josef@toxicpanda.com

Closes: https://github.com/containers/composefs/issues/144
Reviewed-by: Sandeep Dhavale <dhavale@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240830032840.3783206-1-hsiangkao@linux.alibaba.com
2024-09-10 15:26:35 +08:00
Hongzhen Luo
5b5c96c63d erofs: simplify readdir operation
- Use i_size instead of i_size_read() due to immutable fses;

 - Get rid of an unneeded goto since erofs_fill_dentries() also works;

 - Remove unnecessary lines.

Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240801112622.2164029-1-hongzhen@linux.alibaba.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-08-19 11:06:20 +08:00
Gao Xiang
5a7cce827e erofs: refine z_erofs_{init,exit}_subsystem()
Introduce z_erofs_{init,exit}_decompressor() to unexport
z_erofs_{deflate,lzma,zstd}_{init,exit}().

Besides, call them in z_erofs_{init,exit}_subsystem()
for simplicity.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240709094106.3018109-2-hsiangkao@linux.alibaba.com
2024-07-09 19:04:40 +08:00
Gao Xiang
1a4821a0a0 erofs: convert z_erofs_pcluster_readmore() to folios
Unlike `pagecache_get_page()`, `__filemap_get_folio()` returns error
pointers instead of NULL, thus switching to `IS_ERR_OR_NULL`.

Apart from that, it's just a straightforward conversion.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240703120051.3653452-1-hsiangkao@linux.alibaba.com
2024-07-08 22:09:41 +08:00
Al Viro
e09815446d erofs: mechanically convert erofs_read_metabuf() to offsets
just lift the call of erofs_pos() into the callers; it will
collapse in most of them, but that's better done caller-by-caller.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20240425195846.GC1031757@ZenIV
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-05-18 01:46:18 +08:00
Hongzhen Luo
c34110e0fd erofs: clean up erofs_show_options()
Avoid unnecessary #ifdefs and simplify the code a bit.

Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240517095652.2282972-1-hongzhen@linux.alibaba.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-05-18 01:42:18 +08:00
Gao Xiang
20c02972ec Merge branch 'misc.erofs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git
Al Viro has a series of "->bd_inode elimination" which touches several
subsystems, but he also has EROFS-specific further cleanup patches
which I tend to go with EROFS tree for more testing.

Let's merge "#misc.erofs" as Al suggested in the previous email [1]:

"#misc.erofs (the first two commits) is put into never-rebased mode;
 you pull it into your tree and do whatever's convenient with the rest.
 I merge the same branch into block_device work; that way it doesn't
 cause conflicts whatever else happens in our trees."

[1] https://lore.kernel.org/r/20240503041542.GV2118490@ZenIV

Signed-off-by: Gao Xiang <xiang@kernel.org>
2024-05-18 01:39:54 +08:00
Gao Xiang
7c35de4df1 erofs: Zstandard compression support
Add Zstandard compression as the 4th supported algorithm since it
becomes more popular now and some end users have asked this for
quite a while [1][2].

Each EROFS physical cluster contains only one valid standard
Zstandard frame as described in [3] so that decompression can be
performed on a per-pcluster basis independently.

Currently, it just leverages multi-call stream decompression APIs with
internal sliding window buffers.  One-shot or bufferless decompression
could be implemented later for even better performance if needed.

[1] https://github.com/erofs/erofs-utils/issues/6
[2] https://lore.kernel.org/r/Y08h+z6CZdnS1XBm@B-P7TQMD6M-0146.lan
[3] https://www.rfc-editor.org/rfc/rfc8478.txt

Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240508234453.17896-1-xiang@kernel.org
2024-05-09 07:46:56 +08:00
Chunhai Guo
0f6273ab46 erofs: add a reserved buffer pool for lz4 decompression
This adds a special global buffer pool (in the end) for reserved pages.

Using a reserved pool for LZ4 decompression significantly reduces the
time spent on extra temporary page allocation for the extreme cases in
low memory scenarios.

The table below shows the reduction in time spent on page allocation for
LZ4 decompression when using a reserved pool. The results were obtained
from multi-app launch benchmarks on ARM64 Android devices running the
5.15 kernel with an 8-core CPU and 8GB of memory. In the benchmark, we
launched 16 frequently-used apps, and the camera app was the last one in
each round. The data in the table is the average time of camera app for
each round.

After using the reserved pool, there was an average improvement of 150ms
in the overall launch time of our camera app, which was obtained from
the systrace log.

+--------------+---------------+--------------+---------+
|              | w/o page pool | w/ page pool |  diff   |
+--------------+---------------+--------------+---------+
| Average (ms) |     3434      |      21      | -99.38% |
+--------------+---------------+--------------+---------+

Based on the benchmark logs, 64 pages are sufficient for 95% of
scenarios. This value can be adjusted with a module parameter
`reserved_pages`. The default value is 0.

This pool is currently only used for the LZ4 decompressor, but it can be
applied to more decompressors if needed.

Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240402131523.2703948-1-guochunhai@vivo.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-05-08 17:12:51 +08:00
Chunhai Guo
f36f3010f6 erofs: rename per-CPU buffers to global buffer pool and make it configurable
It will cost more time if compressed buffers are allocated on demand for
low-latency algorithms (like lz4) so EROFS uses per-CPU buffers to keep
compressed data if in-place decompression is unfulfilled.  While it is kind
of wasteful of memory for a device with hundreds of CPUs, and only a small
number of CPUs concurrently decompress most of the time.

This patch renames it as 'global buffer pool' and makes it configurable.
This allows two or more CPUs to share a common buffer to reduce memory
occupation.

Suggested-by: Gao Xiang <xiang@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Link: https://lore.kernel.org/r/20240402100036.2673604-1-guochunhai@vivo.com
Signed-off-by: Sandeep Dhavale <dhavale@google.com>
Link: https://lore.kernel.org/r/20240408215231.3376659-1-dhavale@google.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-05-08 17:12:49 +08:00
Baokun Li
07abe43a28 erofs: get rid of erofs_fs_context
Instead of allocating the erofs_sb_info in fill_super() allocate it during
erofs_init_fs_context() and ensure that erofs can always have the info
available during erofs_kill_sb(). After this erofs_fs_context is no longer
needed, replace ctx with sbi, no functional changes.

Suggested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20240419123611.947084-2-libaokun1@huawei.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-04-28 20:36:51 +08:00
Al Viro
958b9f85f8 erofs_buf: store address_space instead of inode
... seeing that ->i_mapping is the only thing we want from the inode.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-04-25 00:57:14 -04:00
Al Viro
469ad583c1 erofs: switch erofs_bread() to passing offset instead of block number
Callers are happier that way, especially since we no longer need to
play with splitting offset into block number and offset within block,
passing the former to erofs_bread(), then adding the latter...

erofs_bread() always reads entire pages, anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-04-07 03:04:50 -04:00
Linus Torvalds
f153fbe1ea Changes since last update:
- Some folio conversions for compressed inodes;
 
  - Add compressed inode support over fscache;
 
  - Fix lockdep false positives of erofs_pseudo_mnt.
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Merge tag 'erofs-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs updates from Gao Xiang:
 "In this cycle, we introduce compressed inode support over fscache
  since a lot of native EROFS images are explicitly compressed so that
  EROFS over fscache can be more widely used even without Dragonfly
  Nydus [1].

  Apart from that, there are some folio conversions for compressed
  inodes available as well as a lockdep false positive fix.

  Summary:

   - Some folio conversions for compressed inodes;

   - Add compressed inode support over fscache;

   - Fix lockdep false positives of erofs_pseudo_mnt"

Link: https://nydus.dev [1]

* tag 'erofs-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: support compressed inodes over fscache
  erofs: make iov_iter describe target buffers over fscache
  erofs: fix lockdep false positives on initializing erofs_pseudo_mnt
  erofs: refine managed cache operations to folios
  erofs: convert z_erofs_submissionqueue_endio() to folios
  erofs: convert z_erofs_fill_bio_vec() to folios
  erofs: get rid of `justfound` debugging tag
  erofs: convert z_erofs_do_read_page() to folios
  erofs: convert z_erofs_onlinepage_.* to folios
2024-03-12 13:25:53 -07:00
Jingbo Xu
a1bafc3109 erofs: support compressed inodes over fscache
Since fscache can utilize iov_iter to write dest buffers, bio_vec can
be used in this way too.

To simplify this, pseudo bios are prepared and bio_vec will be filled
with bio_add_page().  And a common .bi_end_io will be called directly
to handle I/O completions.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240308094159.40547-2-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-03-10 18:41:32 +08:00
Baokun Li
0f28be64d1 erofs: fix lockdep false positives on initializing erofs_pseudo_mnt
Lockdep reported the following issue when mounting erofs with a domain_id:

============================================
WARNING: possible recursive locking detected
6.8.0-rc7-xfstests #521 Not tainted
--------------------------------------------
mount/396 is trying to acquire lock:
ffff907a8aaaa0e0 (&type->s_umount_key#50/1){+.+.}-{3:3},
						at: alloc_super+0xe3/0x3d0

but task is already holding lock:
ffff907a8aaa90e0 (&type->s_umount_key#50/1){+.+.}-{3:3},
						at: alloc_super+0xe3/0x3d0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&type->s_umount_key#50/1);
  lock(&type->s_umount_key#50/1);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by mount/396:
 #0: ffff907a8aaa90e0 (&type->s_umount_key#50/1){+.+.}-{3:3},
			at: alloc_super+0xe3/0x3d0
 #1: ffffffffc00e6f28 (erofs_domain_list_lock){+.+.}-{3:3},
			at: erofs_fscache_register_fs+0x3d/0x270 [erofs]

stack backtrace:
CPU: 1 PID: 396 Comm: mount Not tainted 6.8.0-rc7-xfstests #521
Call Trace:
 <TASK>
 dump_stack_lvl+0x64/0xb0
 validate_chain+0x5c4/0xa00
 __lock_acquire+0x6a9/0xd50
 lock_acquire+0xcd/0x2b0
 down_write_nested+0x45/0xd0
 alloc_super+0xe3/0x3d0
 sget_fc+0x62/0x2f0
 vfs_get_super+0x21/0x90
 vfs_get_tree+0x2c/0xf0
 fc_mount+0x12/0x40
 vfs_kern_mount.part.0+0x75/0x90
 kern_mount+0x24/0x40
 erofs_fscache_register_fs+0x1ef/0x270 [erofs]
 erofs_fc_fill_super+0x213/0x380 [erofs]

This is because the file_system_type of both erofs and the pseudo-mount
point of domain_id is erofs_fs_type, so two successive calls to
alloc_super() are considered to be using the same lock and trigger the
warning above.

Therefore add a nodev file_system_type called erofs_anon_fs_type in
fscache.c to silence this complaint. Because kern_mount() takes a
pointer to struct file_system_type, not its (string) name. So we don't
need to call register_filesystem(). In addition, call init_pseudo() in
erofs_anon_init_fs_context() as suggested by Al Viro, so that we can
remove erofs_fc_fill_pseudo_super(), erofs_fc_anon_get_tree(), and
erofs_anon_context_ops.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: a9849560c5 ("erofs: introduce a pseudo mnt to manage shared cookies")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-and-tested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20240307101018.2021925-1-libaokun1@huawei.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-03-10 18:41:32 +08:00
Gao Xiang
706fd68fce erofs: refine managed cache operations to folios
Convert erofs_try_to_free_all_cached_pages() and
z_erofs_cache_release_folio().

Besides, erofs_page_is_managed() is moved to zdata.c and renamed
as erofs_folio_is_managed().

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240305091448.1384242-6-hsiangkao@linux.alibaba.com
2024-03-10 18:41:25 +08:00
Christian Brauner
87b355f448
erofs: port device access to file
Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-20-adbd023e19cc@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-25 12:05:25 +01:00
Linus Torvalds
87a201b43b Changes since last update:
- Fix inode metadata space layout documentation;
 
  - Avoid warning MicroLZMA format anymore;
 
  - Fix erofs_insert_workgroup() lockref usage;
 
  - Some cleanups.
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Merge tag 'erofs-for-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs updates from Gao Xiang:
 "Nothing exciting lands for this cycle, since we're still busying in
  developing support for sub-page blocks and large-folios of compressed
  data for new scenarios on Android.

  In this cycle, MicroLZMA format is marked as stable, and there are
  minor cleanups around documentation and codebase. In addition, it also
  fixes incorrect lockref usage in erofs_insert_workgroup().

  Summary:

   - Fix inode metadata space layout documentation

   - Avoid warning for MicroLZMA format anymore

   - Fix erofs_insert_workgroup() lockref usage

   - Some cleanups"

* tag 'erofs-for-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: fix erofs_insert_workgroup() lockref usage
  erofs: tidy up redundant includes
  erofs: get rid of ROOT_NID()
  erofs: simplify compression configuration parser
  erofs: don't warn MicroLZMA format anymore
  erofs: fix inode metadata space layout description in documentation
2023-11-02 07:53:57 -10:00
Ferry Meng
f5deddce60 erofs: tidy up redundant includes
- Remove unused includes like <linux/parser.h> and <linux/prefetch.h>;

- Move common includes into "internal.h".

Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20231026021627.23284-2-mengferry@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2023-10-31 06:58:49 +08:00
Ferry Meng
6b8a113cae erofs: get rid of ROOT_NID()
Let's open code this helper for simplicity.

Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20231026021627.23284-1-mengferry@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2023-10-31 06:58:35 +08:00
Gao Xiang
efb4fb02ce erofs: simplify compression configuration parser
Move erofs_load_compr_cfgs() into decompressor.c as well as introduce
a callback instead of a hard-coded switch for each algorithm for
simplicity.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20231022130957.11398-1-xiang@kernel.org
2023-10-31 06:57:19 +08:00