Commits
Naohiro Aota committed a4f9a9a635e
fsnotify: handle subfiles' perm events Recently I'm working on fanotify and found the following strange behaviors. I wrote a program to set fanotify_mark on "/tmp/block" and FAN_DENY all events notified. fanotify_mask = FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD: $ cd /tmp/block; cat foo cat: foo: Operation not permitted Operation on the file is blocked as expected. But, fanotify_mask = FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD: $ cd /tmp/block; cat foo aaa It's not blocked anymore. This is confusing behavior. Also reading commit "fsnotify: call fsnotify_parent in perm events", it seems like fsnotify should handle subfiles' perm events as well as the other notify events. With this patch, regardless of FAN_ALL_EVENTS set or not: $ cd /tmp/block; cat foo cat: foo: Operation not permitted Operation on the file is now blocked properly. FS_OPEN_PERM and FS_ACCESS_PERM are not listed on FS_EVENTS_POSS_ON_CHILD. Due to fsnotify_inode_watches_children() check, if you only specify only these events as fsnotify_mask, you don't get subfiles' perm events notified. This patch add the events to FS_EVENTS_POSS_ON_CHILD to get them notified even if only these events are specified to fsnotify_mask. Signed-off-by: Naohiro Aota <naota@elisp.net> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>