xfs: use btree block initialisation functions in growfs

Factor xfs_btree_init_block() to be independent of the btree cursor,
and use the function to initialise btree blocks in the growfs code.
This makes adding support for different format btree blocks simple.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by Rich Johnston <rjohnston@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_btree.c

@@ -853,18 +853,22 @@ xfs_btree_set_sibling(
 	}
 }
 
-STATIC void
+void
 xfs_btree_init_block(
-	struct xfs_btree_cur	*cur,
+	struct xfs_mount *mp,
-	int			level,
+	struct xfs_buf	*bp,
-	int			numrecs,
+	__u32		magic,
-	struct xfs_btree_block	*new)	/* new block */
+	__u16		level,
+	__u16		numrecs,
+	unsigned int	flags)
 {
-	new->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
+	struct xfs_btree_block	*new = XFS_BUF_TO_BLOCK(bp);
+
+	new->bb_magic = cpu_to_be32(magic);
 	new->bb_level = cpu_to_be16(level);
 	new->bb_numrecs = cpu_to_be16(numrecs);
 
-	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
+	if (flags & XFS_BTREE_LONG_PTRS) {
 		new->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
 		new->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 	} else {
@@ -873,6 +877,17 @@ xfs_btree_init_block(
 	}
 }
 
+STATIC void
+xfs_btree_init_block_cur(
+	struct xfs_btree_cur	*cur,
+	int			level,
+	int			numrecs,
+	struct xfs_buf		*bp)
+{
+	xfs_btree_init_block(cur->bc_mp, bp, xfs_magics[cur->bc_btnum],
+			       level, numrecs, cur->bc_flags);
+}
+
 /*
  * Return true if ptr is the last record in the btree and
  * we need to track updateѕ to this record.  The decision
@@ -2183,7 +2198,7 @@ xfs_btree_split(
 		goto error0;
 
 	/* Fill in the btree header for the new right block. */
-	xfs_btree_init_block(cur, xfs_btree_get_level(left), 0, right);
+	xfs_btree_init_block_cur(cur, xfs_btree_get_level(left), 0, rbp);
 
 	/*
 	 * Split the entries between the old and the new block evenly.
@@ -2492,7 +2507,7 @@ xfs_btree_new_root(
 		nptr = 2;
 	}
 	/* Fill in the new block's btree header and log it. */
-	xfs_btree_init_block(cur, cur->bc_nlevels, 2, new);
+	xfs_btree_init_block_cur(cur, cur->bc_nlevels, 2, nbp);
 	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
 	ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
 			!xfs_btree_ptr_is_null(cur, &rptr));

fs/xfs/xfs_btree.h

@@ -378,6 +378,17 @@ xfs_btree_reada_bufs(
 	xfs_agblock_t		agbno,	/* allocation group block number */
 	xfs_extlen_t		count);	/* count of filesystem blocks */
 
+/*
+ * Initialise a new btree block header
+ */
+void
+xfs_btree_init_block(
+	struct xfs_mount *mp,
+	struct xfs_buf	*bp,
+	__u32		magic,
+	__u16		level,
+	__u16		numrecs,
+	unsigned int	flags);
 
 /*
  * Common btree core entry points.

fs/xfs/xfs_fsops.c

@@ -125,7 +125,6 @@ xfs_growfs_data_private(
 	xfs_extlen_t		agsize;
 	xfs_extlen_t		tmpsize;
 	xfs_alloc_rec_t		*arec;
-	struct xfs_btree_block	*block;
 	xfs_buf_t		*bp;
 	int			bucket;
 	int			dpct;
@@ -263,17 +262,14 @@ xfs_growfs_data_private(
 			error = ENOMEM;
 			goto error0;
 		}
-		block = XFS_BUF_TO_BLOCK(bp);
+		xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
-		memset(block, 0, mp->m_sb.sb_blocksize);
+		xfs_btree_init_block(mp, bp, XFS_ABTB_MAGIC, 0, 1, 0);
-		block->bb_magic = cpu_to_be32(XFS_ABTB_MAGIC);
+
-		block->bb_level = 0;
+		arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
-		block->bb_numrecs = cpu_to_be16(1);
-		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
-		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
-		arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
 		arec->ar_blockcount = cpu_to_be32(
 			agsize - be32_to_cpu(arec->ar_startblock));
+
 		error = xfs_bwrite(bp);
 		xfs_buf_relse(bp);
 		if (error)
@@ -289,18 +285,15 @@ xfs_growfs_data_private(
 			error = ENOMEM;
 			goto error0;
 		}
-		block = XFS_BUF_TO_BLOCK(bp);
+		xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
-		memset(block, 0, mp->m_sb.sb_blocksize);
+		xfs_btree_init_block(mp, bp, XFS_ABTC_MAGIC, 0, 1, 0);
-		block->bb_magic = cpu_to_be32(XFS_ABTC_MAGIC);
+
-		block->bb_level = 0;
+		arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
-		block->bb_numrecs = cpu_to_be16(1);
-		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
-		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
-		arec = XFS_ALLOC_REC_ADDR(mp, block, 1);
 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
 		arec->ar_blockcount = cpu_to_be32(
 			agsize - be32_to_cpu(arec->ar_startblock));
 		nfree += be32_to_cpu(arec->ar_blockcount);
+
 		error = xfs_bwrite(bp);
 		xfs_buf_relse(bp);
 		if (error)
@@ -316,13 +309,9 @@ xfs_growfs_data_private(
 			error = ENOMEM;
 			goto error0;
 		}
-		block = XFS_BUF_TO_BLOCK(bp);
+		xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
-		memset(block, 0, mp->m_sb.sb_blocksize);
+		xfs_btree_init_block(mp, bp, XFS_IBT_MAGIC, 0, 0, 0);
-		block->bb_magic = cpu_to_be32(XFS_IBT_MAGIC);
+
-		block->bb_level = 0;
-		block->bb_numrecs = 0;
-		block->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
-		block->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 		error = xfs_bwrite(bp);
 		xfs_buf_relse(bp);
 		if (error)