[PATCH] xfs_repair: update btree ptr when attr node level moves to next buffer

[Brian Foster <bfoster@xxxxxxxxxx>]

xfs_repair walks the attribute fork btree for files with a significant
number of extended attributes. It creates a cursor, walks the leaf
blocks, and verifies the path from each leaf block back to the root of
the tree. Eryu reports that the following test causes xfs_repair to
report corruption on 512b filesystems:

        num_xattrs=577
        for ((i = 1; i <= $num_xattrs; i++)); do
                name="user.attr_$(printf "%04d" $i)"
                setfattr -n $name -v "val_$(printf "%04d" $i)" <file>
        done

xfs_repair complains that the block number of the leaf (level 0) does
not match the block number of the level 1 node block entry. This occurs
as soon as the left-most level 1 node block is completely processed and
the cursor is walked to the next level 1 block in the array. The problem
is that while verify_da_path() updates level 1 of the cursor to the next
level 1 buffer, it fails to correctly update the btree pointer to the
entry list of the new buffer. As a result, the child leaf block of the
next node block is incorrectly validated against the entry list of the
previous node block.

Update verify_da_path() to correctly update the btree pointer to the
entry list of the new node block when the cursor is walked forward at
higher (non-leaf) levels.

Reported-by: Eryu Guan <eguan@xxxxxxxxxx>
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
 repair/attr_repair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/repair/attr_repair.c b/repair/attr_repair.c
index 83a07a8..b76618a 100644
--- a/repair/attr_repair.c
+++ b/repair/attr_repair.c
@@ -562,7 +562,7 @@ verify_da_path(xfs_mount_t  *mp,
                }
 
                newnode = (xfs_da_intnode_t *)XFS_BUF_PTR(bp);
-               btree = M_DIROPS(mp)->node_tree_p(node);
+               btree = M_DIROPS(mp)->node_tree_p(newnode);
                M_DIROPS(mp)->node_hdr_from_disk(&nodehdr, newnode);
 
                /*
-- 
2.1.0