xfs: fix node forward in xfs_node_toosmall

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@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rich Johnston <rjohnston@sgi.com>

diff --git a/libxfs/xfs_da_btree.c b/libxfs/xfs_da_btree.c
index f106e0665b8bf1a36a47d7e569ad5e20edb0f56a..53414f556803a1a4c8f09aa7d8c01cf2f6052dbd 100644 (file)
--- 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) {