[XFS] add get_maxrecs btree operation

Factor xfs_btree_maxrecs into a per-btree operation.

The get_maxrecs method is based on a patch from Dave Chinner.

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32188a
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Bill O'Donnell <billodo@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>

fs/xfs/xfs_alloc_btree.c

@@ -2219,6 +2219,14 @@ xfs_allocbt_dup_cursor(
 			cur->bc_btnum);
 }
 
+STATIC int
+xfs_allocbt_get_maxrecs(
+	struct xfs_btree_cur	*cur,
+	int			level)
+{
+	return cur->bc_mp->m_alloc_mxr[level != 0];
+}
+
 #ifdef XFS_BTREE_TRACE
 ktrace_t	*xfs_allocbt_trace_buf;
 
@@ -2287,6 +2295,7 @@ xfs_allocbt_trace_record(
 
 static const struct xfs_btree_ops xfs_allocbt_ops = {
 	.dup_cursor		= xfs_allocbt_dup_cursor,
+	.get_maxrecs		= xfs_allocbt_get_maxrecs,
 
 #ifdef XFS_BTREE_TRACE
 	.trace_enter		= xfs_allocbt_trace_enter,

fs/xfs/xfs_bmap_btree.c

@@ -2415,6 +2415,14 @@ xfs_bmbt_dup_cursor(
 	return new;
 }
 
+STATIC int
+xfs_bmbt_get_maxrecs(
+	struct xfs_btree_cur	*cur,
+	int			level)
+{
+	return XFS_BMAP_BLOCK_IMAXRECS(level, cur);
+}
+
 #ifdef XFS_BTREE_TRACE
 ktrace_t	*xfs_bmbt_trace_buf;
 
@@ -2502,6 +2510,7 @@ xfs_bmbt_trace_record(
 
 static const struct xfs_btree_ops xfs_bmbt_ops = {
 	.dup_cursor		= xfs_bmbt_dup_cursor,
+	.get_maxrecs		= xfs_bmbt_get_maxrecs,
 
 #ifdef XFS_BTREE_TRACE
 	.trace_enter		= xfs_bmbt_trace_enter,

fs/xfs/xfs_btree.c

@@ -50,31 +50,6 @@ const __uint32_t xfs_magics[XFS_BTNUM_MAX] = {
 	XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
 };
 
-/*
- * Checking routine: return maxrecs for the block.
- */
-STATIC int				/* number of records fitting in block */
-xfs_btree_maxrecs(
-	xfs_btree_cur_t		*cur,	/* btree cursor */
-	xfs_btree_block_t	*block)	/* generic btree block pointer */
-{
-	switch (cur->bc_btnum) {
-	case XFS_BTNUM_BNO:
-	case XFS_BTNUM_CNT:
-		return (int)XFS_ALLOC_BLOCK_MAXRECS(
-				be16_to_cpu(block->bb_level), cur);
-	case XFS_BTNUM_BMAP:
-		return (int)XFS_BMAP_BLOCK_IMAXRECS(
-				be16_to_cpu(block->bb_level), cur);
-	case XFS_BTNUM_INO:
-		return (int)XFS_INOBT_BLOCK_MAXRECS(
-				be16_to_cpu(block->bb_level), cur);
-	default:
-		ASSERT(0);
-		return 0;
-	}
-}
-
 /*
  * External routines.
  */
@@ -207,7 +182,7 @@ xfs_btree_check_lblock(
 		be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 		be16_to_cpu(block->bb_level) == level &&
 		be16_to_cpu(block->bb_numrecs) <=
-			xfs_btree_maxrecs(cur, (xfs_btree_block_t *)block) &&
+			cur->bc_ops->get_maxrecs(cur, level) &&
 		block->bb_leftsib &&
 		(be64_to_cpu(block->bb_leftsib) == NULLDFSBNO ||
 		 XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_leftsib))) &&
@@ -245,7 +220,7 @@ xfs_btree_check_sblock(
 		be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 		be16_to_cpu(block->bb_level) == level &&
 		be16_to_cpu(block->bb_numrecs) <=
-			xfs_btree_maxrecs(cur, (xfs_btree_block_t *)block) &&
+			cur->bc_ops->get_maxrecs(cur, level) &&
 		(be32_to_cpu(block->bb_leftsib) == NULLAGBLOCK ||
 		 be32_to_cpu(block->bb_leftsib) < agflen) &&
 		block->bb_leftsib &&

fs/xfs/xfs_btree.h

@@ -183,6 +183,9 @@ struct xfs_btree_ops {
 	/* cursor operations */
 	struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
 
+	/* records in block/level */
+	int	(*get_maxrecs)(struct xfs_btree_cur *cur, int level);
+
 	/* btree tracing */
 #ifdef XFS_BTREE_TRACE
 	void		(*trace_enter)(struct xfs_btree_cur *, const char *,

fs/xfs/xfs_ialloc_btree.c

@@ -2085,6 +2085,14 @@ xfs_inobt_dup_cursor(
 			cur->bc_private.a.agbp, cur->bc_private.a.agno);
 }
 
+STATIC int
+xfs_inobt_get_maxrecs(
+	struct xfs_btree_cur	*cur,
+	int			level)
+{
+	return cur->bc_mp->m_inobt_mxr[level != 0];
+}
+
 #ifdef XFS_BTREE_TRACE
 ktrace_t	*xfs_inobt_trace_buf;
 
@@ -2153,6 +2161,7 @@ xfs_inobt_trace_record(
 
 static const struct xfs_btree_ops xfs_inobt_ops = {
 	.dup_cursor		= xfs_inobt_dup_cursor,
+	.get_maxrecs		= xfs_inobt_get_maxrecs,
 
 #ifdef XFS_BTREE_TRACE
 	.trace_enter		= xfs_inobt_trace_enter,