[PATCH] fs: Make sure data stored into inode is properly seen before unlocking new inode

[Jan Kara <jack@suse.cz>]

In theory it could happen that on one CPU we initialize a new inode but clearing
of I_NEW | I_LOCK gets reordered before some of the initialization. Thus on
another CPU we return not fully uptodate inode from iget_locked().

This seems to fix a corruption issue on ext3 mounted over NFS.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/inode.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

  Since Al doesn't seem to be online, does anybody else have opinion on this
patch? I can merge it via my tree but I'd like to get a review from someone
else.

diff --git a/fs/inode.c b/fs/inode.c
index 901bad1..e9a8e77 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -696,6 +696,7 @@ void unlock_new_inode(struct inode *inode)
 	 * just created it (so there can be no old holders
 	 * that haven't tested I_LOCK).
 	 */
+	smp_mb();
 	WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW));
 	inode->i_state &= ~(I_LOCK|I_NEW);
 	wake_up_inode(inode);
-- 
1.6.0.2