kernel/linux.git/fs/fuse/dir.c, branch v6.18.34

fuse: fix uninit-value in fuse_dentry_revalidate()

2026-06-01T15:50:37+00:00

commit 5a6baf204610589f8a5b5a1cd69d1fe661d9d3cd upstream. fuse_dentry_revalidate() may be called with a dentry that didn't had ->d_time initialised. The issue was found with KMSAN, where lookup_open() calls __d_alloc(), followed by d_revalidate(), as shown below: ===================================================== BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394 d_revalidate fs/namei.c:1030 [inline] lookup_open fs/namei.c:4405 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x1614/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] Uninit was created at: slab_post_alloc_hook mm/slub.c:4466 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807 __d_alloc+0x55/0xa00 fs/dcache.c:1740 d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604 lookup_open fs/namei.c:4398 [inline] open_last_lookups fs/namei.c:4583 [inline] path_openat+0x135f/0x64c0 fs/namei.c:4827 do_file_open+0x2aa/0x680 fs/namei.c:4859 [...] ===================================================== Reported-by: syzbot+fdebb2dc960aa56c600a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69917e0d.050a0220.340abe.02e2.GAE@google.com Fixes: 2396356a945b ("fuse: add more control over cache invalidation behaviour") Signed-off-by: Luis Henriques Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

Merge tag 'pull-finish_no_open' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2025-10-03T17:59:31+00:00

Pull finish_no_open updates from Al Viro: "finish_no_open calling conventions change to simplify callers" * tag 'pull-finish_no_open' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: slightly simplify nfs_atomic_open() simplify gfs2_atomic_open() simplify fuse_atomic_open() simplify nfs_atomic_open_v23() simplify vboxsf_dir_atomic_open() simplify cifs_atomic_open() 9p: simplify v9fs_vfs_atomic_open_dotl() 9p: simplify v9fs_vfs_atomic_open() allow finish_no_open(file, ERR_PTR(-E...))

simplify fuse_atomic_open()

2025-09-17T03:59:38+00:00

Reviewed-by: NeilBrown Signed-off-by: Al Viro

fuse: fix fuseblk i_blkbits for iomap partial writes

2025-08-26T10:43:31+00:00

On regular fuse filesystems, i_blkbits is set to PAGE_SHIFT which means any iomap partial writes will mark the entire folio as uptodate. However fuseblk filesystems work differently and allow the blocksize to be less than the page size. As such, this may lead to data corruption if fuseblk sets its blocksize to less than the page size, uses the writeback cache, and does a partial write, then a read and the read happens before the write has undergone writeback, since the folio will not be marked uptodate from the partial write so the read will read in the entire folio from disk, which will overwrite the partial write. The long-term solution for this, which will also be needed for fuse to enable large folios with the writeback cache on, is to have fuse also use iomap for folio reads, but until that is done, the cleanest workaround is to use the page size for fuseblk's internal kernel inode blksize/blkbits values while maintaining current behavior for stat(). This was verified using ntfs-3g: $ sudo mkfs.ntfs -f -c 512 /dev/vdd1 $ sudo ntfs-3g /dev/vdd1 ~/fuseblk $ stat ~/fuseblk/hi.txt IO Block: 512 Fixes: a4c9ab1d4975 ("fuse: use iomap for buffered writes") Signed-off-by: Joanne Koong Reviewed-by: Darrick J. Wong Signed-off-by: Miklos Szeredi

fuse: reflect cached blocksize if blocksize was changed

2025-08-26T10:43:31+00:00

As pointed out by Miklos[1], in the fuse_update_get_attr() path, the attributes returned to stat may be cached values instead of fresh ones fetched from the server. In the case where the server returned a modified blocksize value, we need to cache it and reflect it back to stat if values are not re-fetched since we now no longer directly change inode->i_blkbits. Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguCOxeVX88_zPd1hqziB_C+tmfuDhZP5qO2nKmnb-dTUA@mail.gmail.com/ [1] Fixes: 542ede096e48 ("fuse: keep inode->i_blkbits constant") Signed-off-by: Joanne Koong Reviewed-by: Darrick J. Wong Signed-off-by: Miklos Szeredi

fuse: no need for special dentry_operations for root dentry

2025-06-11T02:15:18+00:00

->d_revalidate() is never called for root anyway... Reviewed-by: Christian Brauner Acked-by: Miklos Szeredi Signed-off-by: Al Viro

Merge tag 'fuse-update-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2025-06-02T22:31:05+00:00

Pull fuse updates from Miklos Szeredi: - Remove tmp page copying in writeback path (Joanne). This removes ~300 lines and with that a lot of complexity related to avoiding reclaim related deadlock. The old mechanism is replaced with a mapping flag that tells the MM not to block reclaim waiting for writeback to complete. The MM parts have been reviewed/acked by respective maintainers. - Convert more code to handle large folios (Joanne). This still just adds the code to deal with large folios and does not enable them yet. - Allow invalidating all cached lookups atomically (Luis Henriques). This feature is useful for CernVMFS, which currently does this iteratively. - Align write prefaulting in fuse with generic one (Dave Hansen) - Fix race causing invalid data to be cached when setting attributes on different nodes of a distributed fs (Guang Yuan Wu) - Update documentation for passthrough (Chen Linxuan) - Add fdinfo about the device number associated with an opened /dev/fuse instance (Chen Linxuan) - Increase readdir buffer size (Miklos). This depends on a patch to VFS readdir code that was already merged through Christians tree. - Optimize io-uring request expiration (Joanne) - Misc cleanups * tag 'fuse-update-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (25 commits) fuse: increase readdir buffer size readdir: supply dir_context.count as readdir buffer size hint fuse: don't allow signals to interrupt getdents copying fuse: support large folios for writeback fuse: support large folios for readahead fuse: support large folios for queued writes fuse: support large folios for stores fuse: support large folios for symlinks fuse: support large folios for folio reads fuse: support large folios for writethrough writes fuse: refactor fuse_fill_write_pages() fuse: support large folios for retrieves fuse: support copying large folios fs: fuse: add dev id to /dev/fuse fdinfo docs: filesystems: add fuse-passthrough.rst MAINTAINERS: update filter of FUSE documentation fuse: fix race between concurrent setattrs from multiple nodes fuse: remove tmp folio for writebacks and internal rb tree mm: skip folio reclaim in legacy memcg contexts for deadlockable mappings fuse: optimize over-io-uring request expiration check ...

Merge tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2025-05-30T22:38:29+00:00

Pull automount updates from Al Viro: "Automount wart removal A bunch of odd boilerplate gone from instances - the reason for those was the need to protect the yet-to-be-attched mount from mark_mounts_for_expiry() deciding to take it out. But that's easy to detect and take care of in mark_mounts_for_expiry() itself; no need to have every instance simulate mount being busy by grabbing an extra reference to it, with finish_automount() undoing that once it attaches that mount. Should've done it that way from the very beginning... This is a flagday change, thankfully there are very few instances. vfs_submount() is gone - its sole remaining user (trace_automount) had been switched to saner primitives" * tag 'pull-automount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: kill vfs_submount() saner calling conventions for ->d_automount()

fuse: support large folios for symlinks

2025-05-29T10:31:23+00:00

Support large folios for symlinks and change the name from fuse_getlink_page() to fuse_getlink_folio(). Signed-off-by: Joanne Koong Reviewed-by: Josef Bacik Reviewed-by: Jeff Layton Reviewed-by: Bernd Schubert Signed-off-by: Miklos Szeredi

fs: Pass a folio to page_put_link()

2025-05-15T10:14:29+00:00

All callers now have a folio. Pass it to page_put_link(), saving a hidden call to compound_head(). Also add kernel-doc for page_get_link() and page_put_link(). Signed-off-by: "Matthew Wilcox (Oracle)" Link: https://lore.kernel.org/20250514171316.3002934-4-willy@infradead.org Signed-off-by: Christian Brauner