kernel/linux.git/fs/notify/mark.c, branch v5.10.257

fsnotify: clear PARENT_WATCHED flags lazily

2024-09-12T09:06:41+00:00

[ Upstream commit 172e422ffea20a89bfdc672741c1aad6fbb5044e ] In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users. Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children. When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child. Suggested-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Stephen Brennan Signed-off-by: Jan Kara Signed-off-by: Sasha Levin

fsnotify: allow adding an inode mark without pinning inode

2024-06-21T12:53:40+00:00

[ Upstream commit c3638b5b13740fa31762d414bbce8b7a694e582a ] fsnotify_add_mark() and variants implicitly take a reference on inode when attaching a mark to an inode. Make that behavior opt-out with the mark flag FSNOTIFY_MARK_FLAG_NO_IREF. Instead of taking the inode reference when attaching connector to inode and dropping the inode reference when detaching connector from inode, take the inode reference on attach of the first mark that wants to hold an inode reference and drop the inode reference on detach of the last mark that wants to hold an inode reference. Backends can "upgrade" an existing mark to take an inode reference, but cannot "downgrade" a mark with inode reference to release the refernce. This leaves the choice to the backend whether or not to pin the inode when adding an inode mark. This is intended to be used when adding a mark with ignored mask that is used for optimization in cases where group can afford getting unneeded events and reinstate the mark with ignored mask when inode is accessed again after being evicted. Link: https://lore.kernel.org/r/20220422120327.3459282-12-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: create helpers for group mark_mutex lock

2024-06-21T12:53:39+00:00

[ Upstream commit 43b245a788e2d8f1bb742668a9bdace02fcb3e96 ] Create helpers to take and release the group mark_mutex lock. Define a flag FSNOTIFY_GROUP_NOFS in fsnotify_group that determines if the mark_mutex lock is fs reclaim safe or not. If not safe, the lock helpers take the lock and disable direct fs reclaim. In that case we annotate the mutex with a different lockdep class to express to lockdep that an allocation of mark of an fs reclaim safe group may take the group lock of another "NOFS" group to evict inodes. For now, converted only the callers in common code and no backend defines the NOFS flag. It is intended to be set by fanotify for evictable marks support. Link: https://lore.kernel.org/r/20220422120327.3459282-7-amir73il@gmail.com Suggested-by: Jan Kara Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/ Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: make allow_dups a property of the group

2024-06-21T12:53:39+00:00

[ Upstream commit f3010343d9e119da35ee864b3a28993bb5c78ed7 ] Instead of passing the allow_dups argument to fsnotify_add_mark() as an argument, define the group flag FSNOTIFY_GROUP_DUPS to express the allow_dups behavior and set this behavior at group creation time for all calls of fsnotify_add_mark(). Rename the allow_dups argument to generic add_flags argument for future use. Link: https://lore.kernel.org/r/20220422120327.3459282-6-amir73il@gmail.com Suggested-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: fix merge with parent's ignored mask

2024-06-21T12:53:38+00:00

[ Upstream commit 4f0b903ded728c505850daf2914bfc08841f0ae6 ] fsnotify_parent() does not consider the parent's mark at all unless the parent inode shows interest in events on children and in the specific event. So unless parent added an event to both its mark mask and ignored mask, the event will not be ignored. Fix this by declaring the interest of an object in an event when the event is in either a mark mask or ignored mask. Link: https://lore.kernel.org/r/20220223151438.790268-2-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: separate mark iterator type from object type enum

2024-06-21T12:53:27+00:00

[ Upstream commit 1c9007d62bea6fd164285314f7553f73e5308863 ] They are two different types that use the same enum, so this confusing. Use the object type to indicate the type of object mark is attached to and the iter type to indicate the type of watch. A group can have two different watches of the same object type (parent and child watches) that match the same event. Link: https://lore.kernel.org/r/20211129201537.1932819-3-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: clarify object type argument

2024-06-21T12:53:27+00:00

[ Upstream commit ad69cd9972e79aba103ba5365de0acd35770c265 ] In preparation for separating object type from iterator type, rename some 'type' arguments in functions to 'obj_type' and remove the unused interface to clear marks by object type mask. Link: https://lore.kernel.org/r/20211129201537.1932819-2-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: fix sb_connectors leak

2024-06-21T12:53:20+00:00

[ Upstream commit 4396a73115fc8739083536162e2228c0c0c3ed1a ] Fix a leak in s_fsnotify_connectors counter in case of a race between concurrent add of new fsnotify mark to an object. The task that lost the race fails to drop the counter before freeing the unused connector. Following umount() hangs in fsnotify_sb_delete()/wait_var_event(), because s_fsnotify_connectors never drops to zero. Fixes: ec44610fe2b8 ("fsnotify: count all objects with attached connectors") Reported-by: Murphy Zhou Link: https://lore.kernel.org/linux-fsdevel/20210907063338.ycaw6wvhzrfsfdlp@xzhoux.usersys.redhat.com/ Signed-off-by: Amir Goldstein Signed-off-by: Linus Torvalds Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: count all objects with attached connectors

2024-06-21T12:53:17+00:00

[ Upstream commit ec44610fe2b86daef70f3f53f47d2a2542d7094f ] Rename s_fsnotify_inode_refs to s_fsnotify_connectors and count all objects with attached connectors, not only inodes with attached connectors. This will be used to optimize fsnotify() calls on sb without any type of marks. Link: https://lore.kernel.org/r/20210810151220.285179-4-amir73il@gmail.com Signed-off-by: Amir Goldstein Reviewed-by: Matthew Bobrowski Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

fsnotify: count s_fsnotify_inode_refs for attached connectors

2024-06-21T12:53:17+00:00

[ Upstream commit 11fa333b58ba1518e7c69fafb6513a0117f8fe33 ] Instead of incrementing s_fsnotify_inode_refs when detaching connector from inode, increment it earlier when attaching connector to inode. Next patch is going to use s_fsnotify_inode_refs to count all objects with attached connectors. Link: https://lore.kernel.org/r/20210810151220.285179-3-amir73il@gmail.com Reviewed-by: Matthew Bobrowski Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin