linux.git/fs/notify/fanotify, branch vm-bind

fanotify: refine the validation checks on non-dir inode mask

2022-06-28T09:18:13+00:00

Commit ceaf69f8eadc ("fanotify: do not allow setting dirent events in mask of non-dir") added restrictions about setting dirent events in the mask of a non-dir inode mark, which does not make any sense. For backward compatibility, these restictions were added only to new (v5.17+) APIs. It also does not make any sense to set the flags FAN_EVENT_ON_CHILD or FAN_ONDIR in the mask of a non-dir inode. Add these flags to the dir-only restriction of the new APIs as well. Move the check of the dir-only flags for new APIs into the helper fanotify_events_supported(), which is only called for FAN_MARK_ADD, because there is no need to error on an attempt to remove the dir-only flags from non-dir inode. Fixes: ceaf69f8eadc ("fanotify: do not allow setting dirent events in mask of non-dir") Link: https://lore.kernel.org/linux-fsdevel/20220627113224.kr2725conevh53u4@quack3.lan/ Link: https://lore.kernel.org/r/20220627174719.2838175-1-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

Merge tag 'fsnotify_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

2022-05-26T02:29:54+00:00

Pull fsnotify updates from Jan Kara: "The biggest part of this is support for fsnotify inode marks that don't pin inodes in memory but rather get evicted together with the inode (they are useful if userspace needs to exclude receipt of events from potentially large subtrees using fanotify ignore marks). There is also a fix for more consistent handling of events sent to parent and a fix of sparse(1) complaints" * tag 'fsnotify_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fanotify: fix incorrect fmode_t casts fsnotify: consistent behavior for parent not watching children fsnotify: introduce mark type iterator fanotify: enable "evictable" inode marks fanotify: use fsnotify group lock helpers fanotify: implement "evictable" inode marks fanotify: factor out helper fanotify_mark_update_flags() fanotify: create helper fanotify_mark_user_flags() fsnotify: allow adding an inode mark without pinning inode dnotify: use fsnotify group lock helpers nfsd: use fsnotify group lock helpers audit: use fsnotify group lock helpers inotify: use fsnotify group lock helpers fsnotify: create helpers for group mark_mutex lock fsnotify: make allow_dups a property of the group fsnotify: pass flags argument to fsnotify_alloc_group() fsnotify: fix wrong lockdep annotations inotify: move control flags from mask to mark flags inotify: show inotify mask flags in proc fdinfo

fanotify: fix incorrect fmode_t casts

2022-05-23T09:42:53+00:00

Fixes sparce warnings: fs/notify/fanotify/fanotify_user.c:267:63: sparse: warning: restricted fmode_t degrades to integer fs/notify/fanotify/fanotify_user.c:1351:28: sparse: warning: restricted fmode_t degrades to integer FMODE_NONTIFY have bitwise fmode_t type and requires __force attribute for any casts. Signed-off-by: Vasily Averin Reviewed-by: Christian Brauner (Microsoft) Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/9adfd6ac-1b89-791e-796b-49ada3293985@openvz.org

fsnotify: consistent behavior for parent not watching children

2022-05-18T13:08:09+00:00

The logic for handling events on child in groups that have a mark on the parent inode, but without FS_EVENT_ON_CHILD flag in the mask is duplicated in several places and inconsistent. Move the logic into the preparation of mark type iterator, so that the parent mark type will be excluded from all mark type iterations in that case. This results in several subtle changes of behavior, hopefully all desired changes of behavior, for example: - Group A has a mount mark with FS_MODIFY in mask - Group A has a mark with ignore mask that does not survive FS_MODIFY and does not watch children on directory D. - Group B has a mark with FS_MODIFY in mask that does watch children on directory D. - FS_MODIFY event on file D/foo should not clear the ignore mask of group A, but before this change it does And if group A ignore mask was set to survive FS_MODIFY: - FS_MODIFY event on file D/foo should be reported to group A on account of the mount mark, but before this change it is wrongly ignored Fixes: 2f02fd3fa13e ("fanotify: fix ignore mask logic for events on child and on dir") Reported-by: Jan Kara Link: https://lore.kernel.org/linux-fsdevel/20220314113337.j7slrb5srxukztje@quack3.lan/ Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220511190213.831646-3-amir73il@gmail.com

fsnotify: introduce mark type iterator

2022-05-18T13:07:43+00:00

fsnotify_foreach_iter_mark_type() is used to reduce boilerplate code of iterating all marks of a specific group interested in an event by consulting the iterator report_mask. Use an open coded version of that iterator in fsnotify_iter_next() that collects all marks of the current iteration group without consulting the iterator report_mask. At the moment, the two iterator variants are the same, but this decoupling will allow us to exclude some of the group's marks from reporting the event, for example for event on child and inode marks on parent did not request to watch events on children. Fixes: 2f02fd3fa13e ("fanotify: fix ignore mask logic for events on child and on dir") Reported-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220511190213.831646-2-amir73il@gmail.com

fanotify: do not allow setting dirent events in mask of non-dir

2022-05-09T09:49:09+00:00

Dirent events (create/delete/move) are only reported on watched directory inodes, but in fanotify as well as in legacy inotify, it was always allowed to set them on non-dir inode, which does not result in any meaningful outcome. Until kernel v5.17, dirent events in fanotify also differed from events "on child" (e.g. FAN_OPEN) in the information provided in the event. For example, FAN_OPEN could be set in the mask of a non-dir or the mask of its parent and event would report the fid of the child regardless of the marked object. By contrast, FAN_DELETE is not reported if the child is marked and the child fid was not reported in the events. Since kernel v5.17, with fanotify group flag FAN_REPORT_TARGET_FID, the fid of the child is reported with dirent events, like events "on child", which may create confusion for users expecting the same behavior as events "on child" when setting events in the mask on a child. The desired semantics of setting dirent events in the mask of a child are not clear, so for now, deny this action for a group initialized with flag FAN_REPORT_TARGET_FID and for the new event FAN_RENAME. We may relax this restriction in the future if we decide on the semantics and implement them. Fixes: d61fd650e9d2 ("fanotify: introduce group flag FAN_REPORT_TARGET_FID") Fixes: 8cc3b1ccd930 ("fanotify: wire up FAN_RENAME event") Link: https://lore.kernel.org/linux-fsdevel/20220505133057.zm5t6vumc4xdcnsg@quack3.lan/ Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20220507080028.219826-1-amir73il@gmail.com

fanotify: enable "evictable" inode marks

2022-04-25T12:43:08+00:00

Now that the direct reclaim path is handled we can enable evictable inode marks. Link: https://lore.kernel.org/r/20220422120327.3459282-17-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fanotify: use fsnotify group lock helpers

2022-04-25T12:43:07+00:00

Direct reclaim from fanotify mark allocation context may try to evict inodes with evictable marks of the same group and hit this deadlock: [<0>] fsnotify_destroy_mark+0x1f/0x3a [<0>] fsnotify_destroy_marks+0x71/0xd9 [<0>] __destroy_inode+0x24/0x7e [<0>] destroy_inode+0x2c/0x67 [<0>] dispose_list+0x49/0x68 [<0>] prune_icache_sb+0x5b/0x79 [<0>] super_cache_scan+0x11c/0x16f [<0>] shrink_slab.constprop.0+0x23e/0x40f [<0>] shrink_node+0x218/0x3e7 [<0>] do_try_to_free_pages+0x12a/0x2d2 [<0>] try_to_free_pages+0x166/0x242 [<0>] __alloc_pages_slowpath.constprop.0+0x30c/0x903 [<0>] __alloc_pages+0xeb/0x1c7 [<0>] cache_grow_begin+0x6f/0x31e [<0>] fallback_alloc+0xe0/0x12d [<0>] ____cache_alloc_node+0x15a/0x17e [<0>] kmem_cache_alloc_trace+0xa1/0x143 [<0>] fanotify_add_mark+0xd5/0x2b2 [<0>] do_fanotify_mark+0x566/0x5eb [<0>] __x64_sys_fanotify_mark+0x21/0x24 [<0>] do_syscall_64+0x6d/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xae Set the FSNOTIFY_GROUP_NOFS flag to prevent going into direct reclaim from allocations under fanotify group lock and use the safe group lock helpers. Link: https://lore.kernel.org/r/20220422120327.3459282-16-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

fanotify: implement "evictable" inode marks

2022-04-25T12:43:03+00:00

When an inode mark is created with flag FAN_MARK_EVICTABLE, it will not pin the marked inode to inode cache, so when inode is evicted from cache due to memory pressure, the mark will be lost. When an inode mark with flag FAN_MARK_EVICATBLE is updated without using this flag, the marked inode is pinned to inode cache. When an inode mark is updated with flag FAN_MARK_EVICTABLE but an existing mark already has the inode pinned, the mark update fails with error EEXIST. Evictable inode marks can be used to setup inode marks with ignored mask to suppress events from uninteresting files or directories in a lazy manner, upon receiving the first event, without having to iterate all the uninteresting files or directories before hand. The evictbale inode mark feature allows performing this lazy marks setup without exhausting the system memory with pinned inodes. This change does not enable the feature yet. Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxiRDpuS=2uA6+ZUM7yG9vVU-u212tkunBmSnP_u=mkv=Q@mail.gmail.com/ Link: https://lore.kernel.org/r/20220422120327.3459282-15-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fanotify: factor out helper fanotify_mark_update_flags()

2022-04-25T12:43:01+00:00

Handle FAN_MARK_IGNORED_SURV_MODIFY flag change in a helper that is called after updating the mark mask. Replace the added and removed return values and help variables with bool recalc return values and help variable, which makes the code a bit easier to follow. Rename flags argument to fan_flags to emphasize the difference from mark->flags. Link: https://lore.kernel.org/r/20220422120327.3459282-14-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara