xfs: encode the max btree height in the cursor

Encode the maximum btree height in the cursor, since we're soon going to
allow smaller cursors for AG btrees and larger cursors for file btrees.

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

4 files changed, 12 insertions, 10 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 3ff4ca794095..cd97288f6abc 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -240,7 +240,7 @@ xfs_bmap_get_bp(
 	if (!cur)
 		return NULL;
 
-	for (i = 0; i < XFS_BTREE_MAXLEVELS; i++) {
+	for (i = 0; i < cur->bc_maxlevels; i++) {
 		if (!cur->bc_levels[i].bp)
 			break;
 		if (xfs_buf_daddr(cur->bc_levels[i].bp) == bno)
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 1d6f465e0e4b..29ce6aca58f5 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2944,7 +2944,7 @@ xfs_btree_promote_leaf_iroot(
 	/* Zap the old root and change the tree height. */
 	xfs_iroot_free(cur->bc_ino.ip, cur->bc_ino.whichfork);
 	cur->bc_nlevels++;
-	ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
+	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
 	cur->bc_levels[1].ptr = 1;
 
 	/*
@@ -3000,7 +3000,7 @@ xfs_btree_promote_node_iroot(
 	 */
 	be16_add_cpu(&block->bb_level, 1);
 	cur->bc_nlevels++;
-	ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
+	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
 	cur->bc_levels[level + 1].ptr = 1;
 
 	/*
@@ -3237,7 +3237,7 @@ xfs_btree_new_root(
 	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
 	cur->bc_levels[cur->bc_nlevels].ptr = nptr;
 	cur->bc_nlevels++;
-	ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
+	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
 	*stat = 1;
 	return 0;
 error0:
@@ -5255,6 +5255,7 @@ xfs_btree_alloc_cursor(
 	cur->bc_mp = mp;
 	cur->bc_btnum = btnum;
 	cur->bc_blocklog = mp->m_sb.sb_blocklog;
+	cur->bc_maxlevels = XFS_BTREE_MAXLEVELS;
 
 	return cur;
 }
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 559bbd823af8..c6dd9ba461b3 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -238,9 +238,10 @@ struct xfs_btree_cur
 	struct xfs_mount	*bc_mp;	/* file system mount struct */
 	const struct xfs_btree_ops *bc_ops;
 	uint			bc_flags; /* btree features - below */
-	union xfs_btree_irec	bc_rec;	/* current insert/search record value */
+	uint8_t		bc_maxlevels;	/* maximum levels for this btree type */
 	uint8_t		bc_nlevels;	/* number of levels in the tree */
 	uint8_t		bc_blocklog;	/* log2(blocksize) of btree blocks */
+	union xfs_btree_irec	bc_rec;	/* current insert/search record value */
 	xfs_btnum_t	bc_btnum;	/* identifies which btree type */
 	int		bc_statoff;	/* offset of btre stats array */
 
diff --git a/fs/xfs/libxfs/xfs_btree_staging.c b/fs/xfs/libxfs/xfs_btree_staging.c
index 6d9c89d8c918..03e23ce17314 100644
--- a/fs/xfs/libxfs/xfs_btree_staging.c
+++ b/fs/xfs/libxfs/xfs_btree_staging.c
@@ -664,12 +664,12 @@ xfs_btree_bload_compute_geometry(
 	 * checking levels 0 and 1 here, so set bc_nlevels such that the btree
 	 * code doesn't interpret either as the root level.
 	 */
-	cur->bc_nlevels = XFS_BTREE_MAXLEVELS - 1;
+	cur->bc_nlevels = cur->bc_maxlevels - 1;
 	xfs_btree_bload_ensure_slack(cur, &bbl->leaf_slack, 0);
 	xfs_btree_bload_ensure_slack(cur, &bbl->node_slack, 1);
 
 	bbl->nr_records = nr_this_level = nr_records;
-	for (cur->bc_nlevels = 1; cur->bc_nlevels <= XFS_BTREE_MAXLEVELS;) {
+	for (cur->bc_nlevels = 1; cur->bc_nlevels <= cur->bc_maxlevels;) {
 		uint64_t	level_blocks;
 		uint64_t	dontcare64;
 		unsigned int	level = cur->bc_nlevels - 1;
@@ -712,7 +712,7 @@ xfs_btree_bload_compute_geometry(
 			 * block-based btree level.
 			 */
 			cur->bc_nlevels++;
-			ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
+			ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
 			xfs_btree_bload_level_geometry(cur, bbl, level,
 					nr_this_level, &avg_per_block,
 					&level_blocks, &dontcare64);
@@ -728,14 +728,14 @@ xfs_btree_bload_compute_geometry(
 
 			/* Otherwise, we need another level of btree. */
 			cur->bc_nlevels++;
-			ASSERT(cur->bc_nlevels <= XFS_BTREE_MAXLEVELS);
+			ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
 		}
 
 		nr_blocks += level_blocks;
 		nr_this_level = level_blocks;
 	}
 
-	if (cur->bc_nlevels > XFS_BTREE_MAXLEVELS)
+	if (cur->bc_nlevels > cur->bc_maxlevels)
 		return -EOVERFLOW;
 
 	bbl->btree_height = cur->bc_nlevels;