[PATCH 13/36] xfs: fix node forward in xfs_node_toosmall

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

When a node is considered for a merge with a sibling, it overwrites the
sibling pointers of the original incore nodehdr with the sibling's
pointers.  This leads to loop considering the original node as a merge
candidate with itself in the second pass, and so it incorrectly
determines a merge should occur.)

Ported from equivalent kernel commit 997def25.

Signed-off-by: Dave Chinner <dchinner at redhat.com>
Reviewed-by: Christoph Hellwig <hch at lst.de>
---
 libxfs/xfs_da_btree.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libxfs/xfs_da_btree.c b/libxfs/xfs_da_btree.c
index f106e06..53414f5 100644
--- a/libxfs/xfs_da_btree.c
+++ b/libxfs/xfs_da_btree.c
@@ -1201,6 +1201,7 @@ xfs_da3_node_toosmall(
 	/* start with smaller blk num */
 	forward = nodehdr.forw < nodehdr.back;
 	for (i = 0; i < 2; forward = !forward, i++) {
+		struct xfs_da3_icnode_hdr thdr;
 		if (forward)
 			blkno = nodehdr.forw;
 		else
@@ -1213,10 +1214,10 @@ xfs_da3_node_toosmall(
 			return(error);
 
 		node = bp->b_addr;
-		xfs_da3_node_hdr_from_disk(&nodehdr, node);
+		xfs_da3_node_hdr_from_disk(&thdr, node);
 		xfs_trans_brelse(state->args->trans, bp);
 
-		if (count - nodehdr.count >= 0)
+		if (count - thdr.count >= 0)
 			break;	/* fits with at least 25% to spare */
 	}
 	if (i >= 2) {
-- 
1.8.4.rc3