Currently, .fadvise() doesn't work well if page cache sharing is on
since shared inodes belong to a pseudo fs generated with init_pseudo(),
and sb->s_bdi is the default one &noop_backing_dev_info.
Then, generic_fadvise() will just behave as a no-op if sb->s_bdi is
&noop_backing_dev_info, but as the bdev fs (the bdev fs changes
inode_to_bdi() instead), it's actually NOT a pure memfs.
Let's generate a real bdi for erofs_ishare_mnt instead.
Fixes: d86d7817c0 ("erofs: implement .fadvise for page cache share")
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Refine the description to better highlight its features and use cases.
In addition, add instructions for building it as a module and clarify
the compression option.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
The bio completion path in the process context (e.g. dm-verity)
will directly call into decompression rather than trigger another
workqueue context for minimal scheduling latencies, which can
then call vm_map_ram() with GFP_KERNEL.
Due to insufficient memory, vm_map_ram() may generate memory
swapping I/O, which can cause submit_bio_wait to deadlock
in some scenarios.
Trimmed down the call stack, as follows:
f2fs_submit_read_io
submit_bio //bio_list is initialized.
mmc_blk_mq_recovery
z_erofs_endio
vm_map_ram
__pte_alloc_kernel
__alloc_pages_direct_reclaim
shrink_folio_list
__swap_writepage
submit_bio_wait //bio_list is non-NULL, hang!!!
Use memalloc_noio_{save,restore}() to wrap up this path.
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jiucheng Xu <jiucheng.xu@amlogic.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
For file-backed mount, IO requests are handled by vfs_iocb_iter_read().
However, it can be interrupted by SIGKILL, returning the number of
bytes actually copied. Unused folios in bio are unexpectedly marked
as uptodate.
vfs_read
filemap_read
filemap_get_pages
filemap_readahead
erofs_fileio_readahead
erofs_fileio_rq_submit
vfs_iocb_iter_read
filemap_read
filemap_get_pages <= detect signal
erofs_fileio_ki_complete <= set all folios uptodate
This patch addresses this by setting short read bio with an error
directly.
Fixes: bc804a8d7e ("erofs: handle end of filesystem properly for file-backed mounts")
Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Yunlei He <heyunlei@xiaomi.com>
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Only plain data whose start position and on-disk physical length are
both aligned to the block size should be classified as interlaced
plain extents. Otherwise, it must be treated as shifted plain extents.
This issue was found by syzbot using a crafted compressed image
containing plain extents with unaligned physical lengths, which can
cause OOB read in z_erofs_transform_plain().
Reported-and-tested-by: syzbot+d988dc155e740d76a331@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/699d5714.050a0220.cdd3c.03e7.GAE@google.com
Fixes: 1d191b4ca5 ("erofs: implement encoded extent metadata")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Many #ifdefs can be replaced with IS_ENABLED() to improve code
readability. No functional changes.
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Inode with identical data but different @aops cannot be mixed
because the page cache is managed by different subsystems (e.g.,
@aops for compressed on-disk inodes cannot handle plain on-disk
inodes).
In this patch, we never allow inodes to share the page cache
among plain, compressed, and fileio cases. When a shared inode
is created, we initialize @aops that is the same as the initial
real inode, and subsequent inodes cannot share the page cache
if the inferred @aops differ from the corresponding shared inode.
This is reasonable as a first step because, in typical use cases,
if an inode is compressible, it will fall into compressed
inodes across different filesystem images unless users use plain
filesystems. However, in that cases, users will use plain
filesystems all the time.
Fixes: 5ef3208e3b ("erofs: introduce the page cache share feature")
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This converts some of the visually simpler cases that have been split
over multiple lines. I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.
Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script. I probably had made it a bit _too_ trivial.
So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.
The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Total patches: 36
Reviews/patch: 1.77
Reviewed rate: 83%
- The 2 patch series "mm/vmscan: fix demotion targets checks in
reclaim/demotion" from Bing Jiao fixes a couple of issues in the
demotion code - pages were failed demotion and were finding themselves
demoted into disallowed nodes.
- The 11 patch series "Remove XA_ZERO from error recovery of dup_mmap()"
from Liam Howlett fixes a rare mapledtree race and performs a number of
cleanups.
- The 13 patch series "mm: add bitmap VMA flag helpers and convert all
mmap_prepare to use them" from Lorenzo Stoakes implements a lot of
cleanups following on from the conversion of the VMA flags into a
bitmap.
- The 5 patch series "support batch checking of references and unmapping
for large folios" from Baolin Wang implements batching to greatly
improve the performance of reclaiming clean file-backed large folios.
- The 3 patch series "selftests/mm: add memory failure selftests" from
Miaohe Lin does as claimed.
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Merge tag 'mm-stable-2026-02-18-19-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- "mm/vmscan: fix demotion targets checks in reclaim/demotion" fixes a
couple of issues in the demotion code - pages were failed demotion
and were finding themselves demoted into disallowed nodes (Bing Jiao)
- "Remove XA_ZERO from error recovery of dup_mmap()" fixes a rare
mapledtree race and performs a number of cleanups (Liam Howlett)
- "mm: add bitmap VMA flag helpers and convert all mmap_prepare to use
them" implements a lot of cleanups following on from the conversion
of the VMA flags into a bitmap (Lorenzo Stoakes)
- "support batch checking of references and unmapping for large folios"
implements batching to greatly improve the performance of reclaiming
clean file-backed large folios (Baolin Wang)
- "selftests/mm: add memory failure selftests" does as claimed (Miaohe
Lin)
* tag 'mm-stable-2026-02-18-19-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (36 commits)
mm/page_alloc: clear page->private in free_pages_prepare()
selftests/mm: add memory failure dirty pagecache test
selftests/mm: add memory failure clean pagecache test
selftests/mm: add memory failure anonymous page test
mm: rmap: support batched unmapping for file large folios
arm64: mm: implement the architecture-specific clear_flush_young_ptes()
arm64: mm: support batch clearing of the young flag for large folios
arm64: mm: factor out the address and ptep alignment into a new helper
mm: rmap: support batched checks of the references for large folios
tools/testing/vma: add VMA userland tests for VMA flag functions
tools/testing/vma: separate out vma_internal.h into logical headers
tools/testing/vma: separate VMA userland tests into separate files
mm: make vm_area_desc utilise vma_flags_t only
mm: update all remaining mmap_prepare users to use vma_flags_t
mm: update shmem_[kernel]_file_*() functions to use vma_flags_t
mm: update secretmem to use VMA flags on mmap_prepare
mm: update hugetlbfs to use VMA flags on mmap_prepare
mm: add basic VMA flag operation helper functions
tools: bitmap: add missing bitmap_[subset(), andnot()]
mm: add mk_vma_flags() bitmap flag macro helper
...
We will be shortly removing the vm_flags_t field from vm_area_desc so we
need to update all mmap_prepare users to only use the dessc->vma_flags
field.
This patch achieves that and makes all ancillary changes required to make
this possible.
This lays the groundwork for future work to eliminate the use of
vm_flags_t in vm_area_desc altogether and more broadly throughout the
kernel.
While we're here, we take the opportunity to replace VM_REMAP_FLAGS with
VMA_REMAP_FLAGS, the vma_flags_t equivalent.
No functional changes intended.
Link: https://lkml.kernel.org/r/fb1f55323799f09fe6a36865b31550c9ec67c225.1769097829.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Damien Le Moal <dlemoal@kernel.org> [zonefs]
Acked-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Yury Norov <ynorov@nvidia.com>
Cc: Chris Mason <clm@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
- Support inode page cache sharing among filesystems
- Formally separate optional encoded (aka compressed) inode layouts
(and the implementations) from the EROFS core on-disk aligned plain
format for future zero-trust security usage
- Improve performance by caching the fact that an inode does not have
a POSIX ACL
- Improve LZ4 decompression error reporting
- Enable LZMA by default and promote DEFLATE and Zstandard algorithms
out of EXPERIMENTAL status
- Switch to inode_set_cached_link() to cache symlink lengths
- random bugfixes and minor cleanups
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Merge tag 'erofs-for-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull erofs updates from Gao Xiang:
"In this cycle, inode page cache sharing among filesystems on the same
machine is now supported, which is particularly useful for
high-density hosts running tens of thousands of containers.
In addition, we fully isolate the EROFS core on-disk format from other
optional encoded layouts since the core on-disk part is designed to be
simple, effective, and secure. Users can use the core format to build
unique golden immutable images and import their filesystem trees
directly from raw block devices via DMA, page-mapped DAX devices,
and/or file-backed mounts without having to worry about unnecessary
intrinsic consistency issues found in other generic filesystems by
design. However, the full vision is still working in progress and will
spend more time to achieve final goals.
There are other improvements and bug fixes as usual, as listed below:
- Support inode page cache sharing among filesystems
- Formally separate optional encoded (aka compressed) inode layouts
(and the implementations) from the EROFS core on-disk aligned plain
format for future zero-trust security usage
- Improve performance by caching the fact that an inode does not have
a POSIX ACL
- Improve LZ4 decompression error reporting
- Enable LZMA by default and promote DEFLATE and Zstandard algorithms
out of EXPERIMENTAL status
- Switch to inode_set_cached_link() to cache symlink lengths
- random bugfixes and minor cleanups"
* tag 'erofs-for-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs: (31 commits)
erofs: fix UAF issue for file-backed mounts w/ directio option
erofs: update compression algorithm status
erofs: fix inline data read failure for ztailpacking pclusters
erofs: avoid some unnecessary #ifdefs
erofs: handle end of filesystem properly for file-backed mounts
erofs: separate plain and compressed filesystems formally
erofs: use inode_set_cached_link()
erofs: mark inodes without acls in erofs_read_inode()
erofs: implement .fadvise for page cache share
erofs: support compressed inodes for page cache share
erofs: support unencoded inodes for page cache share
erofs: pass inode to trace_erofs_read_folio
erofs: introduce the page cache share feature
erofs: using domain_id in the safer way
erofs: add erofs_inode_set_aops helper to set the aops
erofs: support user-defined fingerprint name
erofs: decouple `struct erofs_anon_fs_type`
fs: Export alloc_empty_backing_file
erofs: tidy up erofs_init_inode_xattrs()
erofs: add missing documentation about `directio` mount option
...
Please consider pulling these changes from the signed vfs-7.0-rc1.iomap tag.
Thanks!
Christian
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Merge tag 'vfs-7.0-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs iomap updates from Christian Brauner:
- Erofs page cache sharing preliminaries:
Plumb a void *private parameter through iomap_read_folio() and
iomap_readahead() into iomap_iter->private, matching iomap DIO. Erofs
uses this to replace a bogus kmap_to_page() call, as preparatory work
for page cache sharing.
- Fix for invalid folio access:
Fix an invalid folio access when a folio without iomap_folio_state
is fully submitted to the IO helper — the helper may call
folio_end_read() at any time, so ctx->cur_folio must be invalidated
after full submission.
* tag 'vfs-7.0-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
iomap: fix invalid folio access after folio_end_read()
erofs: hold read context in iomap_iter if needed
iomap: stash iomap read ctx in the private field of iomap_iter
Please consider pulling these changes from the signed vfs-7.0-rc1.fserror tag.
Thanks!
Christian
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Merge tag 'vfs-7.0-rc1.fserror' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs error reporting updates from Christian Brauner:
"This contains the changes to support generic I/O error reporting.
Filesystems currently have no standard mechanism for reporting
metadata corruption and file I/O errors to userspace via fsnotify.
Each filesystem (xfs, ext4, erofs, f2fs, etc.) privately defines
EFSCORRUPTED, and error reporting to fanotify is inconsistent or
absent entirely.
This introduces a generic fserror infrastructure built around struct
super_block that gives filesystems a standard way to queue metadata
and file I/O error reports for delivery to fsnotify.
Errors are queued via mempools and queue_work to avoid holding
filesystem locks in the notification path; unmount waits for pending
events to drain. A new super_operations::report_error callback lets
filesystem drivers respond to file I/O errors themselves (to be used
by an upcoming XFS self-healing patchset).
On the uapi side, EFSCORRUPTED and EUCLEAN are promoted from private
per-filesystem definitions to canonical errno.h values across all
architectures"
* tag 'vfs-7.0-rc1.fserror' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
ext4: convert to new fserror helpers
xfs: translate fsdax media errors into file "data lost" errors when convenient
xfs: report fs metadata errors via fsnotify
iomap: report file I/O errors to the VFS
fs: report filesystem and file I/O errors to fsnotify
uapi: promote EFSCORRUPTED and EUCLEAN to errno.h
The following changes are proposed in the upcoming Linux 7.0:
- Enable LZMA support by default, as it's already in use by Fedora 42/43
and some Android vendors for minimal filesystem sizes;
- Promote DEFLATE and Zstandard out of EXPERIMENTAL status, given that
they have been landed and well-tested for over a year and are
already ready for general use.
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Compressed folios for ztailpacking pclusters must be valid before adding
these pclusters to I/O chains. Otherwise, z_erofs_decompress_pcluster()
may assume they are already valid and then trigger a NULL pointer
dereference.
It is somewhat hard to reproduce because the inline data is in the same
block as the tail of the compressed indexes, which are usually read just
before. However, it may still happen if a fatal signal arrives while
read_mapping_folio() is running, as shown below:
erofs: (device dm-1): z_erofs_pcluster_begin: failed to get inline data -4
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
...
pc : z_erofs_decompress_queue+0x4c8/0xa14
lr : z_erofs_decompress_queue+0x160/0xa14
sp : ffffffc08b3eb3a0
x29: ffffffc08b3eb570 x28: ffffffc08b3eb418 x27: 0000000000001000
x26: ffffff8086ebdbb8 x25: ffffff8086ebdbb8 x24: 0000000000000001
x23: 0000000000000008 x22: 00000000fffffffb x21: dead000000000700
x20: 00000000000015e7 x19: ffffff808babb400 x18: ffffffc089edc098
x17: 00000000c006287d x16: 00000000c006287d x15: 0000000000000004
x14: ffffff80ba8f8000 x13: 0000000000000004 x12: 00000006589a77c9
x11: 0000000000000015 x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : ffffffffffffffe0 x3 : 0000000000000020
x2 : 0000000000000008 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
z_erofs_decompress_queue+0x4c8/0xa14
z_erofs_runqueue+0x908/0x97c
z_erofs_read_folio+0x128/0x228
filemap_read_folio+0x68/0x128
filemap_get_pages+0x44c/0x8b4
filemap_read+0x12c/0x5b8
generic_file_read_iter+0x4c/0x15c
do_iter_readv_writev+0x188/0x1e0
vfs_iter_read+0xac/0x1a4
backing_file_read_iter+0x170/0x34c
ovl_read_iter+0xf0/0x140
vfs_read+0x28c/0x344
ksys_read+0x80/0xf0
__arm64_sys_read+0x24/0x34
invoke_syscall+0x60/0x114
el0_svc_common+0x88/0xe4
do_el0_svc+0x24/0x30
el0_svc+0x40/0xa8
el0t_64_sync_handler+0x70/0xbc
el0t_64_sync+0x1bc/0x1c0
Fix this by reading the inline data before allocating and adding
the pclusters to the I/O chains.
Fixes: cecf864d3d ("erofs: support inline data decompression")
Reported-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Reviewed-and-tested-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
They can either be removed or replaced with IS_ENABLED().
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
I/O requests beyond the end of the filesystem should be zeroed out,
similar to loopback devices and that is what we expect.
Fixes: ce63cb62d7 ("erofs: support unencoded inodes for fileio")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
The EROFS on-disk format uses a tiny, plain metadata design that
prioritizes performance and minimizes complex inconsistencies against
common writable disk filesystems (almost all serious metadata
inconsistency cannot happen in well-designed immutable filesystems like
EROFS). EROFS deliberately avoids artificial design flaws to eliminate
serious security risks from untrusted remote sources by design,
although human-made implementation bugs can still happen sometimes.
Currently, there is no strict check to prevent compressed inodes,
especially LZ4-compressed inodes, from being read in plain filesystems.
Starting with erofs-utils 1.0 and Linux 5.3, LZ4_0PADDING sb feature
is automatically enabled for LZ4-compressed EROFS images to support
in-place decompression. Furthermore, since Linux 5.4 LTS is no longer
supported, we no longer need to handle ancient LZ4-compressed EROFS
images generated by erofs-utils prior to 1.0.
To formally distinguish different filesystem types for improved
security:
- Use the presence of LZ4_0PADDING or a non-zero
`dsb->u1.lz4_max_distance` as a marker for compressed filesystems
containing LZ4-compressed inodes only;
- For other algorithms, use `dsb->u1.available_compr_algs` bitmap.
Note: LZ4_0PADDING has been supported since Linux 5.4 (the first formal
kernel version), so exposing it via sysfs is no longer necessary and is
now deprecated (but remain it for five more years until 2031):
`dsb->u1` has been strictly non-zero for all EROFS images containing
compressed inodes starting with erofs-utils v1.3 and it is actually
a much better marker for compressed filesystems.
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Similar to commit 91ef18b567 ("ext4: mark inodes without acls in
__ext4_iget()"), the ACL state won't be read when the file owner
performs a lookup, and the RCU fast path for lookups won't work
because the ACL state remains unknown.
If there are no extended attributes, or if the xattr filter
indicates that no ACL xattr is present, call cache_no_acl() directly.
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This patch implements the .fadvise interface for page cache share.
Similar to overlayfs, it drops those clean, unused pages through
vfs_fadvise().
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
The trace_erofs_read_folio accesses inode information through folio,
but this method fails if the real inode is not associated with the
folio(such as in the upcoming page cache sharing case). Therefore,
we pass the real inode to it so that the inode information can be
printed out in that case.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Currently, reading files with different paths (or names) but the same
content will consume multiple copies of the page cache, even if the
content of these page caches is the same. For example, reading
identical files (e.g., *.so files) from two different minor versions of
container images will cost multiple copies of the same page cache,
since different containers have different mount points. Therefore,
sharing the page cache for files with the same content can save memory.
This introduces the page cache share feature in erofs. It allocate a
shared inode and use its page cache as shared. Reads for files
with identical content will ultimately be routed to the page cache of
the shared inode. In this way, a single page cache satisfies
multiple read requests for different files with the same contents.
We introduce new mount option `inode_share` to enable the page
sharing mode during mounting. This option is used in conjunction
with `domain_id` to share the page cache within the same trusted
domain.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Either the existing fscache usecase or the upcoming page
cache sharing case, the `domain_id` should be protected as
sensitive information, so we use the safer helpers to allocate,
free and display domain_id.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Add erofs_inode_set_aops helper to set the inode->i_mapping->a_ops
and use IS_ENABLED to make it cleaner.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
When creating the EROFS image, users can specify the fingerprint name.
This is to prepare for the upcoming inode page cache share.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
- Move the `struct erofs_anon_fs_type` to super.c and expose it
in preparation for the upcoming page cache share feature;
- Remove the `.owner` field, as they are all internal mounts and
fully managed by EROFS. Retaining `.owner` would unnecessarily
increment module reference counts, preventing the EROFS kernel
module from being unloaded.
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Pull 'vfs-7.0.iomap' to allow iomap page cache users to set
`iomap_iter::private` for the upcoming page cache sharing support.
It also includes a patch to avoid triggering inline data reads for
the FIEMAP operation.
Signed-off-by: Gao Xiang <xiang@kernel.org>
Mainly get rid of the use of `struct erofs_xattr_iter`, as it is
no longer needed now that meta buffers are used.
This also simplifies the code and uses an early return when there
are no xattrs.
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
- Get rid of `sbi->opt.max_sync_decompress_pages` since it's fixed as
3 all the time;
- Add Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES in bytes instead of in pages,
since for non-4K pages, 3-page limitation makes no sense;
- Move `sync_decompress` to sbi to avoid unexpected remount impact;
- Fold z_erofs_is_sync_decompress() into its caller;
- Better description of sysfs entry `sync_decompress`.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
It can be simply in xattr.c due to no external users.
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
No external users other than those in xattr.c.
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Crafted EROFS images containing valid volume labels can trigger
incorrect early returns, leading to folio reference leaks.
However, this does not cause system crashes or other severe issues.
Fixes: 1cf12c7177 ("erofs: Add support for FS_IOC_GETFSLABEL")
Cc: stable@kernel.org
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Crafted EROFS images with metadata compression enabled can trigger
incorrect early returns, leading to folio reference leaks.
However, this does not cause system crashes or other severe issues.
Fixes: 414091322c ("erofs: implement metadata compression")
Cc: stable@kernel.org
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
EROFS may allocate temporary pages using GFP_NOWAIT | GFP_NORETRY
when pcl->besteffort is off (e.g., for readahead requests).
If the allocation fails, the original request will fall back to
synchronous read, so the failure is transient.
Such fallback can frequently happen in low memory scenarios, but since
these failures are expected and temporary, avoid printing error
messages like below:
[ 7425.184264] erofs (device sr0): failed to decompress (lz4) -ENOMEM @ pa 148447232 size 28672 => 26788
[ 7426.244267] erofs (device sr0): failed to decompress (lz4) -ENOMEM @ pa 149422080 size 28672 => 15903
[ 7426.245508] erofs (device sr0): failed to decompress (lz4) -ENOMEM @ pa 138440704 size 28672 => 39294
...
[ 7504.258373] erofs (device sr0): failed to decompress (lz4) -ENOMEM @ pa 93581312 size 20480 => 47366
Fixes: 831faabed8 ("erofs: improve decompression error reporting")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Just like what was done for other algorithms, let's propagate detailed
error reasons for LZ4 instead of just -EFSCORRUPTED to users:
"corrupted compressed data":
the compressed data is malformed or
destination buffer is not large enough
"unexpected end of stream":
the compressed stream ends normally, but without producing enough
decompressed data.
"compressed data start not found":
can be returned by z_erofs_fixup_insize().
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
When mounting the EROFS file system, it is necessary to check the
available compression algorithms. At this time, the for_each_set_bit
function can be used to simplify the code logic.
Signed-off-by: Yuwen Chen <ywen.chen@foxmail.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reduce the scope of 'z_erofs_crypto[]' that is not used outside of
'decompressor_crypto.c'.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512102025.4mWeBSsf-lkp@intel.com/
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
%pe will print a symbolic error name (e.g,. -ENOMEM), opposed to the
raw errno (e.g,. -12) produced by PTR_ERR().
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Introduce `struct erofs_iomap_iter_ctx` to hold both `struct page *`
and `void *base`, avoiding bogus use of `kmap_to_page()` in
`erofs_iomap_end()`.
With this change, fiemap and bmap no longer need to read inline data.
Additionally, the upcoming page cache sharing mechanism requires
passing the backing inode pointer to `erofs_iomap_{begin,end}()`, as
I/O accesses must apply to backing inodes rather than anon inodes.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://patch.msgid.link/20260109102856.598531-3-lihongbo22@huawei.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stop definining these privately and instead move them to the uapi
errno.h so that they become canonical instead of copy pasta.
Cc: linux-api@vger.kernel.org
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://patch.msgid.link/176826402587.3490369.17659117524205214600.stgit@frogsfrogsfrogs
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Add the setlease file_operation to erofs_file_fops and erofs_dir_fops,
pointing to generic_setlease. A future patch will change the default
behavior to reject lease attempts with -EINVAL when there is no
setlease file operation defined. Add generic_setlease to retain the
ability to set leases on this filesystem.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260108-setlease-6-20-v1-4-ea4dec9b67fa@kernel.org
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Sheng Yong reported [1] that Android APEX images didn't work with commit
072a7c7cdb ("erofs: don't bother with s_stack_depth increasing for
now") because "EROFS-formatted APEX file images can be stored within an
EROFS-formatted Android system partition."
In response, I sent a quick fat-fingered [PATCH v3] to address the
report. Unfortunately, the updated condition was incorrect:
if (erofs_is_fileio_mode(sbi)) {
- sb->s_stack_depth =
- file_inode(sbi->dif0.file)->i_sb->s_stack_depth + 1;
- if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
- erofs_err(sb, "maximum fs stacking depth exceeded");
+ inode = file_inode(sbi->dif0.file);
+ if ((inode->i_sb->s_op == &erofs_sops && !sb->s_bdev) ||
+ inode->i_sb->s_stack_depth) {
The condition `!sb->s_bdev` is always true for all file-backed EROFS
mounts, making the check effectively a no-op.
The real fix tested and confirmed by Sheng Yong [2] at that time was
[PATCH v3 RESEND], which correctly ensures the following EROFS^2 setup
works:
EROFS (on a block device) + EROFS (file-backed mount)
But sadly I screwed it up again by upstreaming the outdated [PATCH v3].
This patch applies the same logic as the delta between the upstream
[PATCH v3] and the real fix [PATCH v3 RESEND].
Reported-by: Sheng Yong <shengyong1@xiaomi.com>
Closes: https://lore.kernel.org/r/3acec686-4020-4609-aee4-5dae7b9b0093@gmail.com [1]
Fixes: 072a7c7cdb ("erofs: don't bother with s_stack_depth increasing for now")
Link: https://lore.kernel.org/r/243f57b8-246f-47e7-9fb1-27a771e8e9e8@gmail.com [2]
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
