ocfs2: change ip_unaligned_aio to of type mutex from atomit_t
There is a problem that waitqueue_active() may check stale data thus miss
a wakeup of threads waiting on ip_unaligned_aio.
The valid value of ip_unaligned_aio is only 0 and 1 so we can change it to
be of type mutex thus the above prolem is avoid. Another benifit is that
mutex which works as FIFO is fairer than wake_up_all().
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 621fc73..9f1580b 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -44,7 +44,7 @@
struct rw_semaphore ip_xattr_sem;
/* Number of outstanding AIO's which are not page aligned */
- atomic_t ip_unaligned_aio;
+ struct mutex ip_unaligned_aio;
/* These fields are protected by ip_lock */
spinlock_t ip_lock;