From 311f08acde635e4e5ccea9b9d8c856cc2e0ced95 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Mon, 4 Feb 2013 10:13:11 -0600 Subject: [PATCH] xfs: memory barrier before wake_up_bit() In xfs_ifunlock() there is a call to wake_up_bit() after clearing the flush lock on the xfs inode. This is not guaranteed to be safe, as noted in the comments above wake_up_bit() beginning with: In order for this to function properly, as it uses waitqueue_active() internally, some kind of memory barrier must be done prior to calling this. Signed-off-by: Alex Elder Reviewed-by: Dave Chinner Signed-off-by: Ben Myers --- fs/xfs/xfs_inode.h | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index 22baf6ea4fac..237e7f6f2ab3 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -419,6 +419,7 @@ static inline void xfs_iflock(struct xfs_inode *ip) static inline void xfs_ifunlock(struct xfs_inode *ip) { xfs_iflags_clear(ip, XFS_IFLOCK); + smp_mb(); wake_up_bit(&ip->i_flags, __XFS_IFLOCK_BIT); }