[PATCH 5.10 06/21] xfs: improve the code that checks recovered refcount intent items

[Siddh Raman Pant]

From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>

The code that validates recovered refcount intent items is kind of a
mess -- it doesn't use the standard xfs type validators, and it doesn't
check for things that it should.  Fix the validator function to use the
standard validation helpers and look for more types of obvious errors.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
(cherry picked from commit 0d79781a1aa6a6a567e63294012eee2384f406f2)
Stable-dep-of: 7b5f775be14a ("xfs: fix unmount hang with unflushable inodes stuck in the AIL")
Signed-off-by: Siddh Raman Pant <siddh.raman.pant@xxxxxxxxxx>
---
 fs/xfs/xfs_refcount_item.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
index 83dddec08f3c..2532a2a1cd59 100644
--- a/fs/xfs/xfs_refcount_item.c
+++ b/fs/xfs/xfs_refcount_item.c
@@ -423,27 +423,26 @@ xfs_cui_validate_phys(
 	struct xfs_mount		*mp,
 	struct xfs_phys_extent		*refc)
 {
-	xfs_fsblock_t			startblock_fsb;
-	bool				op_ok;
+	if (refc->pe_flags & ~XFS_REFCOUNT_EXTENT_FLAGS)
+		return false;
 
-	startblock_fsb = XFS_BB_TO_FSB(mp,
-			   XFS_FSB_TO_DADDR(mp, refc->pe_startblock));
 	switch (refc->pe_flags & XFS_REFCOUNT_EXTENT_TYPE_MASK) {
 	case XFS_REFCOUNT_INCREASE:
 	case XFS_REFCOUNT_DECREASE:
 	case XFS_REFCOUNT_ALLOC_COW:
 	case XFS_REFCOUNT_FREE_COW:
-		op_ok = true;
 		break;
 	default:
-		op_ok = false;
-		break;
+		return false;
 	}
-	if (!op_ok || startblock_fsb == 0 ||
-	    refc->pe_len == 0 ||
-	    startblock_fsb >= mp->m_sb.sb_dblocks ||
-	    refc->pe_len >= mp->m_sb.sb_agblocks ||
-	    (refc->pe_flags & ~XFS_REFCOUNT_EXTENT_FLAGS))
+
+	if (refc->pe_startblock + refc->pe_len <= refc->pe_startblock)
+		return false;
+
+	if (!xfs_verify_fsbno(mp, refc->pe_startblock))
+		return false;
+
+	if (!xfs_verify_fsbno(mp, refc->pe_startblock + refc->pe_len - 1))
 		return false;
 
 	return true;
-- 
2.53.0