[PATCH 3.16.y-ckt 042/183] xfs: set superblock buffer type correctly

[Luis Henriques]

3.16.7-ckt8 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Chinner <dchinner at redhat.com>

commit 3443a3bca54588f43286b725d8648d33a38c86f1 upstream.

When the superblock is modified in a transaction, the commonly
modified fields are not actually copied to the superblock buffer to
avoid the buffer lock becoming a serialisation point. However, there
are some other operations that modify the superblock fields within
the transaction that don't directly log to the superblock but rely
on the changes to be applied during the transaction commit (to
minimise the buffer lock hold time).

When we do this, we fail to mark the buffer log item as being a
superblock buffer and that can lead to the buffer not being marked
with the corect type in the log and hence causing recovery issues.
Fix it by setting the type correctly, similar to xfs_mod_sb()...

Tested-by: Jan Kara <jack at suse.cz>
Signed-off-by: Dave Chinner <dchinner at redhat.com>
Reviewed-by: Brian Foster <bfoster at redhat.com>
Signed-off-by: Dave Chinner <david at fromorbit.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/xfs/xfs_trans.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index d03932564ccb..c81f51c290c1 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -474,6 +474,7 @@ xfs_trans_apply_sb_deltas(
 		whole = 1;
 	}
 
+	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SB_BUF);
 	if (whole)
 		/*
 		 * Log the whole thing, the fields are noncontiguous.