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>
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>
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 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>
- Fix a WARNING caused by a recent FSDAX misdetection regression
- Fix the filesystem stacking limit for file-backed mounts
- Print more informative diagnostics on decompression errors
- Switch the on-disk definition `erofs_fs.h` to the MIT license
- Minor cleanups
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Merge tag 'erofs-for-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull erofs updates from Gao Xiang:
- Fix a WARNING caused by a recent FSDAX misdetection regression
- Fix the filesystem stacking limit for file-backed mounts
- Print more informative diagnostics on decompression errors
- Switch the on-disk definition `erofs_fs.h` to the MIT license
- Minor cleanups
* tag 'erofs-for-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: switch on-disk header `erofs_fs.h` to MIT license
erofs: get rid of raw bi_end_io() usage
erofs: enable error reporting for z_erofs_fixup_insize()
erofs: enable error reporting for z_erofs_stream_switch_bufs()
erofs: improve Zstd, LZMA and DEFLATE error strings
erofs: improve decompression error reporting
erofs: tidy up z_erofs_lz4_handle_overlap()
erofs: limit the level of fs stacking for file-backed mounts
erofs: correct FSDAX detection
These BIOs are actually harmless in practice, as they are all pseudo
BIOs and do not use advanced features like chaining. Using the BIO
interface is a more friendly and unified approach for both bdev and
and file-backed I/Os (compared to awkward bvec interfaces).
Let's use bio_endio() instead.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
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
- 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
Previously, file operations on a file-backed mount used the current
process' credentials to access the backing FD. Attempting to do so on
Android lead to SELinux denials, as ACL rules on the backing file (e.g.
/system/apex/foo.apex) is restricted to a small set of process.
Arguably, this error is redundant and leaking implementation details, as
access to files on a mount is already ACL'ed by path.
Instead, override to use the opener's cred when accessing the backing
file. This makes the behavior similar to a loop-backed mount, which
uses kworker cred when accessing the backing file and does not cause
SELinux denials.
Signed-off-by: Tatsuyuki Ishi <ishitatsuyuki@google.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://lore.kernel.org/r/20250612-b4-erofs-impersonate-v1-1-8ea7d6f65171@google.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
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>
If bio_add_folio() fails (because it is full),
erofs_fileio_scan_folio() needs to submit the I/O request via
erofs_fileio_rq_submit() and allocate a new I/O request with an empty
`struct bio`. Then it retries the bio_add_folio() call.
However, at this point, erofs_onlinefolio_split() has already been
called which increments `folio->private`; the retry will call
erofs_onlinefolio_split() again, but there will never be a matching
erofs_onlinefolio_end() call. This leaves the folio locked forever
and all waiters will be stuck in folio_wait_bit_common().
This bug has been added by commit ce63cb62d7 ("erofs: support
unencoded inodes for fileio"), but was practically unreachable because
there was room for 256 folios in the `struct bio` - until commit
9f74ae8c9a ("erofs: shorten bvecs[] for file-backed mounts") which
reduced the array capacity to 16 folios.
It was now trivial to trigger the bug by manually invoking readahead
from userspace, e.g.:
posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED);
This should be fixed by invoking erofs_onlinefolio_split() only after
bio_add_folio() has succeeded. This is safe: asynchronous completions
invoking erofs_onlinefolio_end() will not unlock the folio because
erofs_fileio_scan_folio() is still holding a reference to be released
by erofs_onlinefolio_end() at the end.
Fixes: ce63cb62d7 ("erofs: support unencoded inodes for fileio")
Fixes: 9f74ae8c9a ("erofs: shorten bvecs[] for file-backed mounts")
Cc: stable@vger.kernel.org
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Reviewed-by: Gao Xiang <xiang@kernel.org>
Tested-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://lore.kernel.org/r/20250428230933.3422273-1-max.kellermann@ionos.com
Signed-off-by: Gao Xiang <xiang@kernel.org>
If a file-backed IO fails before submitting the bio to the lower
filesystem, an error is returned, but the bio->bi_status is not
marked as an error. However, the error information should be passed
to the end_io handler. Otherwise, the IO request will be treated as
successful.
Fixes: 283213718f ("erofs: support compressed inodes for fileio")
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250408122351.2104507-1-shengyong1@xiaomi.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
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>
BIO_MAX_VECS is too large for __GFP_NOFAIL allocation. We could use
a mempool (since BIOs can always proceed), but it seems overly
complicated for now.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250107082825.74242-1-hsiangkao@linux.alibaba.com
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
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
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
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
