xfs: stricter btree height checking when scanning for btree roots

When we're scanning for btree roots to rebuild the AG headers, make sure
that the proposed tree does not exceed the maximum height for that btree
type (and not just XFS_BTREE_MAXLEVELS).

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>

fs/xfs/scrub/agheader_repair.c

@@ -122,7 +122,7 @@ xrep_check_btree_root(
 	xfs_agnumber_t			agno = sc->sm->sm_agno;
 
 	return xfs_verify_agbno(mp, agno, fab->root) &&
-	       fab->height <= XFS_BTREE_MAXLEVELS;
+	       fab->height <= fab->maxlevels;
 }
 
 /*
@@ -339,18 +339,22 @@ xrep_agf(
 		[XREP_AGF_BNOBT] = {
 			.rmap_owner = XFS_RMAP_OWN_AG,
 			.buf_ops = &xfs_bnobt_buf_ops,
+			.maxlevels = sc->mp->m_ag_maxlevels,
 		},
 		[XREP_AGF_CNTBT] = {
 			.rmap_owner = XFS_RMAP_OWN_AG,
 			.buf_ops = &xfs_cntbt_buf_ops,
+			.maxlevels = sc->mp->m_ag_maxlevels,
 		},
 		[XREP_AGF_RMAPBT] = {
 			.rmap_owner = XFS_RMAP_OWN_AG,
 			.buf_ops = &xfs_rmapbt_buf_ops,
+			.maxlevels = sc->mp->m_rmap_maxlevels,
 		},
 		[XREP_AGF_REFCOUNTBT] = {
 			.rmap_owner = XFS_RMAP_OWN_REFC,
 			.buf_ops = &xfs_refcountbt_buf_ops,
+			.maxlevels = sc->mp->m_refc_maxlevels,
 		},
 		[XREP_AGF_END] = {
 			.buf_ops = NULL,
@@ -881,10 +885,12 @@ xrep_agi(
 		[XREP_AGI_INOBT] = {
 			.rmap_owner = XFS_RMAP_OWN_INOBT,
 			.buf_ops = &xfs_inobt_buf_ops,
+			.maxlevels = M_IGEO(sc->mp)->inobt_maxlevels,
 		},
 		[XREP_AGI_FINOBT] = {
 			.rmap_owner = XFS_RMAP_OWN_INOBT,
 			.buf_ops = &xfs_finobt_buf_ops,
+			.maxlevels = M_IGEO(sc->mp)->inobt_maxlevels,
 		},
 		[XREP_AGI_END] = {
 			.buf_ops = NULL

fs/xfs/scrub/repair.h

@@ -44,6 +44,9 @@ struct xrep_find_ag_btree {
 	/* in: buffer ops */
 	const struct xfs_buf_ops	*buf_ops;
 
+	/* in: maximum btree height */
+	unsigned int			maxlevels;
+
 	/* out: the highest btree block found and the tree height */
 	xfs_agblock_t			root;
 	unsigned int			height;