[PATCH 6.1.y] xfs: cross-reference the primary superblock

[Sasha Levin <sashal@kernel.org>]

From: "Darrick J. Wong" <djwong@kernel.org>

[ Upstream commit 0c61016006ab08f8346f9e7b1e38559bd4ea499e ]

Make sure we cross-reference the primary superblock against the rest of
the AG 0 space metadata.  Drop the unused @bp parameter of
xchk_superblock_xref to avoid complaints about uninitialized variables.

Cc: stable@vger.kernel.org # v4.16
Fixes: 52dc4b44af7419 ("xfs: cross-reference with the bnobt")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
[ sashal: initialized the error variable to zero in xchk_superblock() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/xfs/scrub/agheader.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
index b7b838bd4ba43..89193f07b451f 100644
--- a/fs/xfs/scrub/agheader.c
+++ b/fs/xfs/scrub/agheader.c
@@ -23,8 +23,7 @@
 /* Cross-reference with the other btrees. */
 STATIC void
 xchk_superblock_xref(
-	struct xfs_scrub	*sc,
-	struct xfs_buf		*bp)
+	struct xfs_scrub	*sc)
 {
 	struct xfs_mount	*mp = sc->mp;
 	xfs_agnumber_t		agno = sc->sm->sm_agno;
@@ -64,16 +63,12 @@ xchk_superblock(
 	struct xfs_buf		*bp;
 	struct xfs_dsb		*sb;
 	struct xfs_perag	*pag;
-	xfs_agnumber_t		agno;
+	xfs_agnumber_t		agno = sc->sm->sm_agno;
 	uint32_t		v2_ok;
 	__be32			features_mask;
-	int			error;
+	int			error = 0;
 	__be16			vernum_mask;
 
-	agno = sc->sm->sm_agno;
-	if (agno == 0)
-		return 0;
-
 	/*
 	 * Grab an active reference to the perag structure.  If we can't get
 	 * it, we're racing with something that's tearing down the AG, so
@@ -83,6 +78,9 @@ xchk_superblock(
 	if (!pag)
 		return -ENOENT;
 
+	if (agno == 0)
+		goto out_xref;
+
 	error = xfs_sb_read_secondary(mp, sc->tp, agno, &bp);
 	/*
 	 * The superblock verifier can return several different error codes
@@ -344,7 +342,8 @@ xchk_superblock(
 			BBTOB(bp->b_length) - sizeof(struct xfs_dsb)))
 		xchk_block_set_corrupt(sc, bp);
 
-	xchk_superblock_xref(sc, bp);
+out_xref:
+	xchk_superblock_xref(sc);
 out_pag:
 	xfs_perag_put(pag);
 	return error;
-- 
2.53.0