[PATCH 081/111] xfs: tighten up validation of root block in inode forks

Darrick J. Wong
2024-06-03T19:13:10Z

From: Christoph Hellwig <hch@lst.de>

Source kernel commit: d477f1749f00899c71605ea01aba0ce67e030471

Check that root blocks that sit in the inode fork and thus have a NULL
bp don't have siblings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
---
libxfs/xfs_btree.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/libxfs/xfs_btree.c b/libxfs/xfs_btree.c
index 0b5002540..2f5848b9d 100644
--- a/libxfs/xfs_btree.c
+++ b/libxfs/xfs_btree.c
@@ -104,7 +104,7 @@ __xfs_btree_check_lblock(
{
struct xfs_mount *mp = cur->bc_mp;
xfs_failaddr_t fa;
- xfs_fsblock_t fsb = NULLFSBLOCK;
+ xfs_fsblock_t fsb;

if (xfs_has_crc(mp)) {
if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
@@ -124,9 +124,19 @@ __xfs_btree_check_lblock(
cur->bc_ops->get_maxrecs(cur, level))
return __this_address;

- if (bp)
- fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
+ /*
+ * For inode-rooted btrees, the root block sits in the inode fork. In
+ * that case bp is NULL, and the block must not have any siblings.
+ */
+ if (!bp) {
+ if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK))
+ return __this_address;
+ if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK))
+ return __this_address;
+ return NULL;
+ }

+ fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
fa = xfs_btree_check_lblock_siblings(mp, fsb, block->bb_u.l.bb_leftsib);
if (!fa)
fa = xfs_btree_check_lblock_siblings(mp, fsb,