kernel/linux.git/fs/file_table.c, branch v6.18.21

fs: move initializing f_mode before file_ref_init()

2026-02-26T22:58:57+00:00

[ Upstream commit 1219e0feaefc9697f738b223540e8e8906291cb3 ] The comment above file_ref_init() says: "We're SLAB_TYPESAFE_BY_RCU so initialize f_ref last." but file_set_fsnotify_mode() was added after file_ref_init(). Move it right after setting f_mode, where it makes more sense. Fixes: 711f9b8fbe4f4 ("fsnotify: disable pre-content and permission events by default") Signed-off-by: Amir Goldstein Link: https://patch.msgid.link/20260109211536.3565697-1-amir73il@gmail.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

fs: update comment in init_file()

2025-10-07T10:48:33+00:00

The f_count member in struct file has been replaced by f_ref, so update f_count to f_ref in the comment. Signed-off-by: Zhou Yuhang Signed-off-by: Christian Brauner

Have cc(1) catch attempts to modify ->f_path

2025-09-28T00:18:41+00:00

There are very few places that have cause to do that - all in core VFS now, and all done to files that are not yet opened (or visible to anybody else, for that matter). Let's turn f_path into a union of struct path __f_path and const struct path f_path. It's C, not C++ - 6.5.2.3[4] in C99 and later explicitly allows that kind of type-punning. That way any attempts to bypass these checks will be either very easy to catch, or (if the bastards get sufficiently creative to make it hard to spot with grep alone) very clearly malicious - and still catchable with a bit of instrumentation for sparse. Reviewed-by: Jan Kara Reviewed-by: Christian Brauner Signed-off-by: Al Viro

backing_file_user_path(): constify struct path *

2025-09-16T01:17:07+00:00

Callers never use the resulting pointer to modify the struct path it points to (nor should they). Reviewed-by: Jan Kara Reviewed-by: Christian Brauner Signed-off-by: Al Viro

Merge tag 'fsnotify_for_v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

2025-07-31T17:31:00+00:00

Pull fsnotify updates from Jan Kara: "A couple of small improvements for fsnotify subsystem. The most interesting is probably Amir's change modifying the meaning of fsnotify fmode bits (and I spell it out specifically because I know you care about those). There's no change for the common cases of no fsnotify watches or no permission event watches. But when there are permission watches (either for open or for pre-content events) but no FAN_ACCESS_PERM watch (which nobody uses in practice) we are now able optimize away unnecessary cache loads from the read path" * tag 'fsnotify_for_v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fsnotify: optimize FMODE_NONOTIFY_PERM for the common cases fsnotify: merge file_set_fsnotify_mode_from_watchers() with open perm hook samples: fix building fs-monitor on musl systems fanotify: sanitize handle_type values when reporting fid

fsnotify: merge file_set_fsnotify_mode_from_watchers() with open perm hook

2025-07-28T16:14:38+00:00

Create helper fsnotify_open_perm_and_set_mode() that moves the fsnotify_open_perm() hook into file_set_fsnotify_mode_from_watchers(). This will allow some more optimizations. Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Link: https://patch.msgid.link/20250708143641.418603-2-amir73il@gmail.com

fs: constify file ptr in backing_file accessor helpers

2025-07-18T09:09:29+00:00

Add internal helper backing_file_set_user_path() for the only two cases that need to modify backing_file fields. Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/20250607115304.2521155-2-amir73il@gmail.com Signed-off-by: Christian Brauner

fs: Make file-nr output the total allocated file handles

2025-04-21T08:27:58+00:00

Make file-nr output the total allocated file handles, not per-cpu cache number, it's more precise, and not in hot path Signed-off-by: Li RongQing Link: https://lore.kernel.org/20250410112117.2851-1-lirongqing@baidu.com Signed-off-by: Christian Brauner

Merge tag 'vfs-6.15-rc1.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-03-24T20:19:17+00:00

Pull vfs file handling updates from Christian Brauner: "This contains performance improvements for struct file's new refcount mechanism and various other performance work: - The stock kernel transitioning the file to no refs held penalizes the caller with an extra atomic to block any increments. For cases where the file is highly likely to be going away this is easily avoidable. Add file_ref_put_close() to better handle the common case where closing a file descriptor also operates on the last reference and build fput_close_sync() and fput_close() on top of it. This brings about 1% performance improvement by eliding one atomic in the common case. - Predict no error in close() since the vast majority of the time system call returns 0. - Reduce the work done in fdget_pos() by predicting that the file was found and by explicitly comparing the reference count to one and ignoring the dead zone" * tag 'vfs-6.15-rc1.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: reduce work in fdget_pos() fs: use fput_close() in path_openat() fs: use fput_close() in filp_close() fs: use fput_close_sync() in close() file: add fput and file_ref_put routines optimized for use when closing a fd fs: predict no error in close()

Merge tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-03-24T16:13:50+00:00

Pull misc vfs updates from Christian Brauner: "Features: - Add CONFIG_DEBUG_VFS infrastucture: - Catch invalid modes in open - Use the new debug macros in inode_set_cached_link() - Use debug-only asserts around fd allocation and install - Place f_ref to 3rd cache line in struct file to resolve false sharing Cleanups: - Start using anon_inode_getfile_fmode() helper in various places - Don't take f_lock during SEEK_CUR if exclusion is guaranteed by f_pos_lock - Add unlikely() to kcmp() - Remove legacy ->remount_fs method from ecryptfs after port to the new mount api - Remove invalidate_inodes() in favour of evict_inodes() - Simplify ep_busy_loopER by removing unused argument - Avoid mmap sem relocks when coredumping with many missing pages - Inline getname() - Inline new_inode_pseudo() and de-staticize alloc_inode() - Dodge an atomic in putname if ref == 1 - Consistently deref the files table with rcu_dereference_raw() - Dedup handling of struct filename init and refcounts bumps - Use wq_has_sleeper() in end_dir_add() - Drop the lock trip around I_NEW wake up in evict() - Load the ->i_sb pointer once in inode_sb_list_{add,del} - Predict not reaching the limit in alloc_empty_file() - Tidy up do_sys_openat2() with likely/unlikely - Call inode_sb_list_add() outside of inode hash lock - Sort out fd allocation vs dup2 race commentary - Turn page_offset() into a wrapper around folio_pos() - Remove locking in exportfs around ->get_parent() call - try_lookup_one_len() does not need any locks in autofs - Fix return type of several functions from long to int in open - Fix return type of several functions from long to int in ioctls Fixes: - Fix watch queue accounting mismatch" * tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits) fs: sort out fd allocation vs dup2 race commentary, take 2 fs: call inode_sb_list_add() outside of inode hash lock fs: tidy up do_sys_openat2() with likely/unlikely fs: predict not reaching the limit in alloc_empty_file() fs: load the ->i_sb pointer once in inode_sb_list_{add,del} fs: drop the lock trip around I_NEW wake up in evict() fs: use wq_has_sleeper() in end_dir_add() VFS/autofs: try_lookup_one_len() does not need any locks fs: dedup handling of struct filename init and refcounts bumps fs: consistently deref the files table with rcu_dereference_raw() exportfs: remove locking around ->get_parent() call. fs: use debug-only asserts around fd allocation and install fs: dodge an atomic in putname if ref == 1 vfs: Remove invalidate_inodes() ecryptfs: remove NULL remount_fs from super_operations watch_queue: fix pipe accounting mismatch fs: place f_ref to 3rd cache line in struct file to resolve false sharing epoll: simplify ep_busy_loop by removing always 0 argument fs: Turn page_offset() into a wrapper around folio_pos() kcmp: improve performance adding an unlikely hint to task comparisons ...