kernel/linux.git/include/linux/fscache.h, branch v6.19.11

Merge patch series "netfs: Miscellaneous fixes"

2025-05-21T12:35:34+00:00

David Howells says: Here are some miscellaneous fixes and changes for netfslib, if you could pull them: (1) Fix an oops in write-retry due to mis-resetting the I/O iterator. (2) Fix the recording of transferred bytes for short DIO reads. (3) Fix a request's work item to not require a reference, thereby avoiding the need to get rid of it in BH/IRQ context. (4) Fix waiting and waking to be consistent about the waitqueue used. * patches from https://lore.kernel.org/20250519090707.2848510-1-dhowells@redhat.com: netfs: Fix wait/wake to be consistent about the waitqueue used netfs: Fix the request's work item to not require a ref netfs: Fix setting of transferred bytes with short DIO reads netfs: Fix oops in write-retry from mis-resetting the subreq iterator Link: https://lore.kernel.org/20250519090707.2848510-1-dhowells@redhat.com Signed-off-by: Christian Brauner

netfs: Fix the request's work item to not require a ref

2025-05-21T12:35:20+00:00

When the netfs_io_request struct's work item is queued, it must be supplied with a ref to the work item struct to prevent it being deallocated whilst on the queue or whilst it is being processed. This is tricky to manage as we have to get a ref before we try and queue it and then we may find it's already queued and is thus already holding a ref - in which case we have to try and get rid of the ref again. The problem comes if we're in BH or IRQ context and need to drop the ref: if netfs_put_request() reduces the count to 0, we have to do the cleanup - but the cleanup may need to wait. Fix this by adding a new work item to the request, ->cleanup_work, and dispatching that when the refcount hits zero. That can then synchronously cancel any outstanding work on the main work item before doing the cleanup. Adding a new work item also deals with another problem upstream where it's sometimes changing the work func in the put function and requeuing it - which has occasionally in the past caused the cleanup to happen incorrectly. As a bonus, this allows us to get rid of the 'was_async' parameter from a bunch of functions. This indicated whether the put function might not be permitted to sleep. Fixes: 3d3c95046742 ("netfs: Provide readahead and readpage netfs helpers") Signed-off-by: David Howells Link: https://lore.kernel.org/20250519090707.2848510-4-dhowells@redhat.com cc: Paulo Alcantara cc: Marc Dionne cc: Steve French cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner

fs/netfs: remove unused enum choice NETFS_READ_HOLE_CLEAR

2025-05-21T12:34:37+00:00

This choice was added by commit 3a11b3a86366 ("netfs: Pass more information on how to deal with a hole in the cache") but the last user was removed by commit 86b374d061ee ("netfs: Remove fs/netfs/io.c"). Signed-off-by: Max Kellermann Signed-off-by: David Howells Link: https://lore.kernel.org/20250519134813.2975312-6-dhowells@redhat.com cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner

netfs: Replace PG_fscache by setting folio->private and marking dirty

2024-04-29T14:01:42+00:00

When dirty data is being written to the cache, setting/waiting on/clearing the fscache flag is always done in tandem with setting/waiting on/clearing the writeback flag. The netfslib buffered write routines wait on and set both flags and the write request cleanup clears both flags, so the fscache flag is almost superfluous. The reason it isn't superfluous is because the fscache flag is also used to indicate that data just read from the server is being written to the cache. The flag is used to prevent a race involving overlapping direct-I/O writes to the cache. Change this to indicate that a page is in need of being copied to the cache by placing a magic value in folio->private and marking the folios dirty. Then when the writeback code sees a folio marked in this way, it only writes it to the cache and not to the server. If a folio that has this magic value set is modified, the value is just replaced and the folio will then be uplodaded too. With this, PG_fscache is no longer required by the netfslib core, 9p and afs. Ceph and nfs, however, still need to use the old PG_fscache-based tracking. To deal with this, a flag, NETFS_ICTX_USE_PGPRIV2, now has to be set on the flags in the netfs_inode struct for those filesystems. This reenables the use of PG_fscache in that inode. 9p and afs use the netfslib write helpers so get switched over; cifs, for the moment, does page-by-page manual access to the cache, so doesn't use PG_fscache and is unaffected. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Matthew Wilcox (Oracle) cc: Eric Van Hensbergen cc: Latchesar Ionkov cc: Dominique Martinet cc: Christian Schoenebeck cc: Marc Dionne cc: Ilya Dryomov cc: Xiubo Li cc: Steve French cc: Paulo Alcantara cc: Ronnie Sahlberg cc: Shyam Prasad N cc: Tom Talpey cc: Bharath SM cc: Trond Myklebust cc: Anna Schumaker cc: netfs@lists.linux.dev cc: v9fs@lists.linux.dev cc: linux-afs@lists.infradead.org cc: ceph-devel@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org

netfs: Move pinning-for-writeback from fscache to netfs

2023-12-24T15:08:49+00:00

Move the resource pinning-for-writeback from fscache code to netfslib code. This is used to keep a cache backing object pinned whilst we have dirty pages on the netfs inode in the pagecache such that VM writeback will be able to reach it. Whilst we're at it, switch the parameters of netfs_unpin_writeback() to match ->write_inode() so that it can be used for that directly. Note that this mechanism could be more generically useful than that for network filesystems. Quite often they have to keep around other resources (e.g. authentication tokens or network connections) until the writeback is complete. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org

netfs, fscache: Remove ->begin_cache_operation

2023-12-24T15:08:48+00:00

Remove ->begin_cache_operation() in favour of just calling fscache directly. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Christian Brauner cc: linux-fsdevel@vger.kernel.org cc: linux-cachefs@redhat.com

fscache: fix OOB Read in __fscache_acquire_volume

2022-11-23T18:31:13+00:00

The type of a->key[0] is char in fscache_volume_same(). If the length of cache volume key is greater than 127, the value of a->key[0] is less than 0. In this case, klen becomes much larger than 255 after type conversion, because the type of klen is size_t. As a result, memcmp() is read out of bounds. This causes a slab-out-of-bounds Read in __fscache_acquire_volume(), as reported by Syzbot. Fix this by changing the type of the stored key to "u8 *" rather than "char *" (it isn't a simple string anyway). Also put in a check that the volume name doesn't exceed NAME_MAX. BUG: KASAN: slab-out-of-bounds in memcmp+0x16f/0x1c0 lib/string.c:757 Read of size 8 at addr ffff888016f3aa90 by task syz-executor344/3613 Call Trace: memcmp+0x16f/0x1c0 lib/string.c:757 memcmp include/linux/fortify-string.h:420 [inline] fscache_volume_same fs/fscache/volume.c:133 [inline] fscache_hash_volume fs/fscache/volume.c:171 [inline] __fscache_acquire_volume+0x76c/0x1080 fs/fscache/volume.c:328 fscache_acquire_volume include/linux/fscache.h:204 [inline] v9fs_cache_session_get_cookie+0x143/0x240 fs/9p/cache.c:34 v9fs_session_init+0x1166/0x1810 fs/9p/v9fs.c:473 v9fs_mount+0xba/0xc90 fs/9p/vfs_super.c:126 legacy_get_tree+0x105/0x220 fs/fs_context.c:610 vfs_get_tree+0x89/0x2f0 fs/super.c:1530 do_new_mount fs/namespace.c:3040 [inline] path_mount+0x1326/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 Fixes: 62ab63352350 ("fscache: Implement volume registration") Reported-by: syzbot+a76f6a6e524cf2080aa3@syzkaller.appspotmail.com Signed-off-by: David Howells Reviewed-by: Zhang Peng Reviewed-by: Jingbo Xu cc: Dominique Martinet cc: Jeff Layton cc: v9fs-developer@lists.sourceforge.net cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/Y3OH+Dmi0QIOK18n@codewreck.org/ # Zhang Peng's v1 fix Link: https://lore.kernel.org/r/20221115140447.2971680-1-zhangpeng362@huawei.com/ # Zhang Peng's v2 fix Link: https://lore.kernel.org/r/166869954095.3793579.8500020902371015443.stgit@warthog.procyon.org.uk/ # v1 Signed-off-by: Linus Torvalds

fscache: fix misdocumented parameter

2022-08-31T13:57:28+00:00

This patch fixes two warnings generated by make docs. The functions fscache_use_cookie and fscache_unuse_cookie, both have a parameter named cookie. But they are documented with the name "object" with unclear description. Which generates the warning when creating docs. This commit will replace the currently misdocumented parameter names with the correct ones while adding proper descriptions. CC: Randy Dunlap Signed-off-by: Khalid Masum Signed-off-by: David Howells Link: https://lore.kernel.org/r/20220521142446.4746-1-khalid.masum.92@gmail.com/ # v1 Link: https://lore.kernel.org/r/20220818040738.12036-1-khalid.masum.92@gmail.com/ # v2 Link: https://lore.kernel.org/r/880d7d25753fb326ee17ac08005952112fcf9bdb.1657360984.git.mchehab@kernel.org/ # Mauro's version

Merge tag 'docs-6.0' of git://git.lwn.net/linux

2022-08-03T02:24:24+00:00

Pull documentation updates from Jonathan Corbet: "This was a moderately busy cycle for documentation, but nothing all that earth-shaking: - More Chinese translations, and an update to the Italian translations. The Japanese, Korean, and traditional Chinese translations are more-or-less unmaintained at this point, instead. - Some build-system performance improvements. - The removal of the archaic submitting-drivers.rst document, with the movement of what useful material that remained into other docs. - Improvements to sphinx-pre-install to, hopefully, give more useful suggestions. - A number of build-warning fixes Plus the usual collection of typo fixes, updates, and more" * tag 'docs-6.0' of git://git.lwn.net/linux: (92 commits) docs: efi-stub: Fix paths for x86 / arm stubs Docs/zh_CN: Update the translation of sched-stats to 5.19-rc8 Docs/zh_CN: Update the translation of pci to 5.19-rc8 Docs/zh_CN: Update the translation of pci-iov-howto to 5.19-rc8 Docs/zh_CN: Update the translation of usage to 5.19-rc8 Docs/zh_CN: Update the translation of testing-overview to 5.19-rc8 Docs/zh_CN: Update the translation of sparse to 5.19-rc8 Docs/zh_CN: Update the translation of kasan to 5.19-rc8 Docs/zh_CN: Update the translation of iio_configfs to 5.19-rc8 doc:it_IT: align Italian documentation docs: Remove spurious tag from admin-guide/mm/overcommit-accounting.rst Documentation: process: Update email client instructions for Thunderbird docs: ABI: correct QEMU fw_cfg spec path doc/zh_CN: remove submitting-driver reference from docs docs: zh_TW: align to submitting-drivers removal docs: zh_CN: align to submitting-drivers removal docs: ko_KR: howto: remove reference to removed submitting-drivers docs: ja_JP: howto: remove reference to removed submitting-drivers docs: it_IT: align to submitting-drivers removal docs: process: remove outdated submitting-drivers.rst ...

docs: filesystems: update netfs-api.rst reference

2022-07-07T19:09:59+00:00

Changeset efc930fa1d84 ("docs: filesystems: caching/netfs-api.txt: convert it to ReST") renamed: Documentation/filesystems/caching/netfs-api.txt to: Documentation/filesystems/caching/netfs-api.rst. Update its cross-reference accordingly. Fixes: efc930fa1d84 ("docs: filesystems: caching/netfs-api.txt: convert it to ReST") Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/5f867f01d42c3e65e111167739ed1a41a26623f9.1656234456.git.mchehab@kernel.org Signed-off-by: Jonathan Corbet