audit: do not set FS_EVENT_ON_CHILD in audit marks mask

The audit group marks mask does not contain any events possible on
a child so setting the flag FS_EVENT_ON_CHILD in the mask is counter
productive.

It may lead to the undesired outcome of setting the dentry flag
DCACHE_FSNOTIFY_PARENT_WATCHED on a directory inode even though it is
not watching children, because the audit mark contribute the flag
FS_EVENT_ON_CHILD to the inode's fsnotify_mask and another mark could
be contributing an event that is possible on child to the inode's mask.

Furthermore in the following patches we want to use FS_EVENT_ON_CHILD
for non-dir inodes for other purposes so stop using the flag.

Link: https://lore.kernel.org/r/20200722125849.17418-4-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Author: amir73il

kernel/audit_fsnotify.c

@@ -36,7 +36,7 @@ static struct fsnotify_group *audit_fsnotify_group;
 
 /* fsnotify events we care about. */
 #define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
-			 FS_MOVE_SELF | FS_EVENT_ON_CHILD)
+			 FS_MOVE_SELF)
 
 static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark)
 {

kernel/audit_watch.c

@@ -53,7 +53,7 @@ static struct fsnotify_group *audit_watch_group;
 
 /* fsnotify events we care about. */
 #define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
-			FS_MOVE_SELF | FS_EVENT_ON_CHILD | FS_UNMOUNT)
+			FS_MOVE_SELF | FS_UNMOUNT)
 
 static void audit_free_parent(struct audit_parent *parent)
 {