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linux/fs/notify
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Jim Somerville 676a0675cf inotify: remove broken mask checks causing unmount to be EINVAL 
Running the command:

	inotifywait -e unmount /mnt/disk

immediately aborts with a -EINVAL return code.  This is however a valid
parameter.  This abort occurs only if unmount is the sole event
parameter.  If other event parameters are supplied, then the unmount
event wait will work.

The problem was introduced by commit 44b350fc23 ("inotify: Fix mask
checks").  In that commit, it states:

	The mask checks in inotify_update_existing_watch() and
	inotify_new_watch() are useless because inotify_arg_to_mask()
	sets FS_IN_IGNORED and FS_EVENT_ON_CHILD bits anyway.

But instead of removing the useless checks, it did this:

	        mask = inotify_arg_to_mask(arg);
	-       if (unlikely(!mask))
	+       if (unlikely(!(mask & IN_ALL_EVENTS)))
	                return -EINVAL;

The problem is that IN_ALL_EVENTS doesn't include IN_UNMOUNT, and other
parts of the code keep IN_UNMOUNT separate from IN_ALL_EVENTS.  So the
check should be:

	if (unlikely(!(mask & (IN_ALL_EVENTS | IN_UNMOUNT))))

But inotify_arg_to_mask(arg) always sets the IN_UNMOUNT bit in the mask
anyway, so the check is always going to pass and thus should simply be
removed.  Also note that inotify_arg_to_mask completely controls what
mask bits get set from arg, there's no way for invalid bits to get
enabled there.

Lets fix it by simply removing the useless broken checks.

Signed-off-by: Jim Somerville <Jim.Somerville@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Eric Paris <eparis@parisplace.org>
Cc: <stable@vger.kernel.org>		[2.6.37+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:16 -08:00
..
dnotify fsnotify: pass group to fsnotify_destroy_mark() 2012-12-11 13:44:36 -05:00
fanotify Merge branch 'for-next' of git://git.infradead.org/users/eparis/notify 2012-12-20 20:11:52 -08:00
inotify inotify: remove broken mask checks causing unmount to be EINVAL 2013-02-21 17:22:16 -08:00
fdinfo.c Merge branch 'for-next' of git://git.infradead.org/users/eparis/notify 2012-12-20 20:11:52 -08:00
fdinfo.h fs, notify: add procfs fdinfo helper 2012-12-17 17:15:28 -08:00
fsnotify.c vfs: switch i_dentry/d_alias to hlist 2012-07-14 16:32:55 +04:00
fsnotify.h fsnotify: remove global fsnotify groups lists 2010-07-28 10:18:54 -04:00
group.c fsnotify: make fasync generic for both inotify and fanotify 2012-12-11 13:44:36 -05:00
inode_mark.c Merge branch 'for-next' of git://git.infradead.org/users/eparis/notify 2012-12-20 20:11:52 -08:00
Kconfig fanotify: allow fanotify to be built 2010-10-28 17:22:13 -04:00
Makefile fs, notify: add procfs fdinfo helper 2012-12-17 17:15:28 -08:00
mark.c fsnotify: change locking order 2012-12-11 13:44:36 -05:00
notification.c Merge branch 'for-next' of git://git.infradead.org/users/eparis/notify 2012-12-20 20:11:52 -08:00
vfsmount_mark.c fsnotify: pass group to fsnotify_destroy_mark() 2012-12-11 13:44:36 -05:00