[PATCH] xfs: scrub: Disable check for non-optimized data fork bmbt node

[Chandan Babu R <chandanrlinux@gmail.com>]

xchk_btree_check_minrecs() checks if the contents of the immediate child of a
bmbt root block can fit within the root block. This check could fail on inodes
with an attr fork since xfs_bmap_add_attrfork_btree() used to demote the
current root node of the data fork as the child of a newly allocated root node
if it found that the size of "struct xfs_btree_block" along with the space
required for records exceeded that of space available in the data fork.

xfs_bmap_add_attrfork_btree() should have used "struct xfs_bmdr_block" instead
of "struct xfs_btree_block" for the above mentioned space requirement
calculation. This commit disables the check for non-optimized (in terms of
disk space usage) data fork bmbt trees since there could be filesystems
in use that already have such a layout.

Reported-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/scrub/btree.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index debf392e0515..79e0aa484b4a 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -9,6 +9,7 @@
 #include "xfs_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
+#include "xfs_inode.h"
 #include "xfs_btree.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
@@ -469,14 +470,17 @@ xchk_btree_check_minrecs(
 	 */
 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 	    level == cur->bc_nlevels - 2) {
+		struct xfs_inode 	*ip = bs->sc->ip;
 		struct xfs_btree_block	*root_block;
 		struct xfs_buf		*root_bp;
 		int			root_maxrecs;
+		int			whichfork = cur->bc_ino.whichfork;
 
 		root_block = xfs_btree_get_block(cur, root_level, &root_bp);
 		root_maxrecs = cur->bc_ops->get_dmaxrecs(cur, root_level);
 		if (be16_to_cpu(root_block->bb_numrecs) != 1 ||
-		    numrecs <= root_maxrecs)
+		    (!(whichfork == XFS_DATA_FORK && XFS_IFORK_Q(ip)) &&
+		     numrecs <= root_maxrecs))
 			xchk_btree_set_corrupt(bs->sc, cur, level);
 		return;
 	}
-- 
2.29.2