kernel.git/fs/notify/fsnotify.c, branch linux-5.16.y

fsnotify: Protect fsnotify_handle_inode_event from no-inode events

2021-10-27T10:34:12Z

FAN_FS_ERROR allows events without inodes - i.e. for file system-wide errors. Even though fsnotify_handle_inode_event is not currently used by fanotify, this patch protects other backends from cases where neither inode or dir are provided. Also document the constraints of the interface (inode and dir cannot be both NULL). Link: https://lore.kernel.org/r/20211025192746.66445-12-krisman@collabora.com Suggested-by: Amir Goldstein Signed-off-by: Gabriel Krisman Bertazi Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Jan Kara

fsnotify: Retrieve super block from the data field

2021-10-27T10:33:52Z

Some file system events (i.e. FS_ERROR) might not be associated with an inode or directory. For these, we can retrieve the super block from the data field. But, since the super_block is available in the data field on every event type, simplify the code to always retrieve it from there, through a new helper. Link: https://lore.kernel.org/r/20211025192746.66445-11-krisman@collabora.com Suggested-by: Jan Kara Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Jan Kara

fsnotify: count all objects with attached connectors

2021-08-11T11:50:48Z

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

fsnotify: fix events reported to watching parent and child

2020-12-11T10:40:43Z

fsnotify_parent() used to send two separate events to backends when a parent inode is watching children and the child inode is also watching. In an attempt to avoid duplicate events in fanotify, we unified the two backend callbacks to a single callback and handled the reporting of the two separate events for the relevant backends (inotify and dnotify). However the handling is buggy and can result in inotify and dnotify listeners receiving events of the type they never asked for or spurious events. The problem is the unified event callback with two inode marks (parent and child) is called when any of the parent and child inodes are watched and interested in the event, but the parent inode's mark that is interested in the event on the child is not necessarily the one we are currently reporting to (it could belong to a different group). So before reporting the parent or child event flavor to backend we need to check that the mark is really interested in that event flavor. The semantics of INODE and CHILD marks were hard to follow and made the logic more complicated than it should have been. Replace it with INODE and PARENT marks semantics to hopefully make the logic more clear. Thanks to Hugh Dickins for spotting a bug in the earlier version of this patch. Fixes: 497b0c5a7c06 ("fsnotify: send event to parent and child with single callback") CC: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201202120713.702387-4-amir73il@gmail.com Reported-by: Hugh Dickins Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: generalize handle_inode_event()

2020-12-03T13:58:35Z

The handle_inode_event() interface was added as (quoting comment): "a simple variant of handle_event() for groups that only have inode marks and don't have ignore mask". In other words, all backends except fanotify. The inotify backend also falls under this category, but because it required extra arguments it was left out of the initial pass of backends conversion to the simple interface. This results in code duplication between the generic helper fsnotify_handle_event() and the inotify_handle_event() callback which also happen to be buggy code. Generalize the handle_inode_event() arguments and add the check for FS_EXCL_UNLINK flag to the generic helper, so inotify backend could be converted to use the simple interface. Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com CC: stable@vger.kernel.org Fixes: b9a1b9772509 ("fsnotify: create method handle_inode_event() in fsnotify_operations") Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fanotify: fix logic of reporting name info with watched parent

2020-11-09T14:03:08Z

The victim inode's parent and name info is required when an event needs to be delivered to a group interested in filename info OR when the inode's parent is interested in an event on its children. Let us call the first condition 'parent_needed' and the second condition 'parent_interested'. In fsnotify_parent(), the condition where the inode's parent is interested in some events on its children, but not necessarily interested the specific event is called 'parent_watched'. fsnotify_parent() tests the condition (!parent_watched && !parent_needed) for sending the event without parent and name info, which is correct. It then wrongly assumes that parent_watched implies !parent_needed and tests the condition (parent_watched && !parent_interested) for sending the event without parent and name info, which is wrong, because parent may still be needed by some group. For example, after initializing a group with FAN_REPORT_DFID_NAME and adding a FAN_MARK_MOUNT with FAN_OPEN mask, open events on non-directory children of "testdir" are delivered with file name info. After adding another mark to the same group on the parent "testdir" with FAN_CLOSE|FAN_EVENT_ON_CHILD mask, open events on non-directory children of "testdir" are no longer delivered with file name info. Fix the logic and use auxiliary variables to clarify the conditions. Fixes: 9b93f33105f5 ("fsnotify: send event with parent/name info to sb/mount/non-dir marks") Cc: stable@vger.kernel.org#v5.9 Link: https://lore.kernel.org/r/20201108105906.8493-1-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: create method handle_inode_event() in fsnotify_operations

2020-07-27T21:25:50Z

The method handle_event() grew a lot of complexity due to the design of fanotify and merging of ignore masks. Most backends do not care about this complex functionality, so we can hide this complexity from them. Introduce a method handle_inode_event() that serves those backends and passes a single inode mark and less arguments. This change converts all backends except fanotify and inotify to use the simplified handle_inode_event() method. In pricipal, inotify could have also used the new method, but that would require passing more arguments on the simple helper (data, data_type, cookie), so we leave it with the handle_event() method. Link: https://lore.kernel.org/r/20200722125849.17418-9-amir73il@gmail.com Suggested-by: Jan Kara Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: send event with parent/name info to sb/mount/non-dir marks

2020-07-27T21:21:02Z

Similar to events "on child" to watching directory, send event with parent/name info if sb/mount/non-dir marks are interested in parent/name info. The FS_EVENT_ON_CHILD flag can be set on sb/mount/non-dir marks to specify interest in parent/name info for events on non-directory inodes. Events on "orphan" children (disconnected dentries) are sent without parent/name info. Events on directories are sent with parent/name info only if the parent directory is watching. After this change, even groups that do not subscribe to events on children could get an event with mark iterator type TYPE_CHILD and without mark iterator type TYPE_INODE if fanotify has marks on the same objects. dnotify and inotify event handlers can already cope with that situation. audit does not subscribe to events that are possible on child, so won't get to this situation. nfsd does not access the marks iterator from its event handler at the moment, so it is not affected. This is a bit too fragile, so we should prepare all groups to cope with mark type TYPE_CHILD preferably using a generic helper. Link: https://lore.kernel.org/r/20200716084230.30611-16-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: pass dir and inode arguments to fsnotify()

2020-07-27T21:15:48Z

The arguments of fsnotify() are overloaded and mean different things for different event types. Replace the to_tell argument with separate arguments @dir and @inode, because we may be sending to both dir and child. Using the @data argument to pass the child is not enough, because dirent events pass this argument (for audit), but we do not report to child. Document the new fsnotify() function argumenets. Link: https://lore.kernel.org/r/20200722125849.17418-7-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: create helper fsnotify_inode()

2020-07-27T21:13:51Z

Simple helper to consolidate biolerplate code. Link: https://lore.kernel.org/r/20200722125849.17418-5-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara