tree 7a179ddd7e233668dbb108faf847ceb768d2e92c
parent 9ebb389d0a03b4415fe9014f6922a2412cb1109c
author Pavel Shilovsky <piastry@etersoft.ru> 1332957379 +0400
committer Steve French <sfrench@us.ibm.com> 1333306467 -0500

CIFS: Fix VFS lock usage for oplocked files

We can deadlock if we have a write oplock and two processes
use the same file handle. In this case the first process can't
unlock its lock if the second process blocked on the lock in the
same time.

Fix it by using posix_lock_file rather than posix_lock_file_wait
under cinode->lock_mutex. If we request a blocking lock and
posix_lock_file indicates that there is another lock that prevents
us, wait untill that lock is released and restart our call.

Cc: stable@kernel.org
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>