xfs: refactor xfs_iread_extents to use xfs_btree_visit_blocks

xfs_iread_extents open-codes everything in xfs_btree_visit_blocks, so
refactor the btree helper to be able to iterate only the records on
level 0, then port iread_extents to use it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 75 insertions, 112 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index f16c6cdf2c58..77e52874e8c5 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1155,6 +1155,65 @@ trans_cancel:
  * Internal and external extent tree search functions.
  */
 
+struct xfs_iread_state {
+	struct xfs_iext_cursor	icur;
+	xfs_extnum_t		loaded;
+};
+
+/* Stuff every bmbt record from this block into the incore extent map. */
+static int
+xfs_iread_bmbt_block(
+	struct xfs_btree_cur	*cur,
+	int			level,
+	void			*priv)
+{
+	struct xfs_iread_state	*ir = priv;
+	struct xfs_mount	*mp = cur->bc_mp;
+	struct xfs_inode	*ip = cur->bc_private.b.ip;
+	struct xfs_btree_block	*block;
+	struct xfs_buf		*bp;
+	struct xfs_bmbt_rec	*frp;
+	xfs_extnum_t		num_recs;
+	xfs_extnum_t		j;
+	int			whichfork = cur->bc_private.b.whichfork;
+
+	block = xfs_btree_get_block(cur, level, &bp);
+
+	/* Abort if we find more records than nextents. */
+	num_recs = xfs_btree_get_numrecs(block);
+	if (unlikely(ir->loaded + num_recs >
+		     XFS_IFORK_NEXTENTS(ip, whichfork))) {
+		xfs_warn(ip->i_mount, "corrupt dinode %llu, (btree extents).",
+				(unsigned long long)ip->i_ino);
+		xfs_inode_verifier_error(ip, -EFSCORRUPTED, __func__, block,
+				sizeof(*block), __this_address);
+		return -EFSCORRUPTED;
+	}
+
+	/* Copy records into the incore cache. */
+	frp = XFS_BMBT_REC_ADDR(mp, block, 1);
+	for (j = 0; j < num_recs; j++, frp++, ir->loaded++) {
+		struct xfs_bmbt_irec	new;
+		xfs_failaddr_t		fa;
+
+		xfs_bmbt_disk_get_all(frp, &new);
+		fa = xfs_bmap_validate_extent(ip, whichfork, &new);
+		if (fa) {
+			xfs_inode_verifier_error(ip, -EFSCORRUPTED,
+					"xfs_iread_extents(2)", frp,
+					sizeof(*frp), fa);
+			return -EFSCORRUPTED;
+		}
+		xfs_iext_insert(ip, &ir->icur, &new,
+				xfs_bmap_fork_to_state(whichfork));
+		trace_xfs_read_extent(ip, &ir->icur,
+				xfs_bmap_fork_to_state(whichfork), _THIS_IP_);
+		xfs_iext_next(XFS_IFORK_PTR(ip, whichfork), &ir->icur);
+	}
+
+	return 0;
+}
+
 /*
  * Read in extents from a btree-format inode.
  */
@@ -1164,134 +1223,38 @@ xfs_iread_extents(
 	struct xfs_inode	*ip,
 	int			whichfork)
 {
-	struct xfs_mount	*mp = ip->i_mount;
-	int			state = xfs_bmap_fork_to_state(whichfork);
+	struct xfs_iread_state	ir;
 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
-	xfs_extnum_t		nextents = XFS_IFORK_NEXTENTS(ip, whichfork);
-	struct xfs_btree_block	*block = ifp->if_broot;
-	struct xfs_iext_cursor	icur;
-	struct xfs_bmbt_irec	new;
-	xfs_fsblock_t		bno;
-	struct xfs_buf		*bp;
-	xfs_extnum_t		i, j;
-	int			level;
-	__be64			*pp;
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_btree_cur	*cur;
 	int			error;
 
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 
 	if (unlikely(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)) {
 		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
-		return -EFSCORRUPTED;
-	}
-
-	/*
-	 * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
-	 */
-	level = be16_to_cpu(block->bb_level);
-	if (unlikely(level == 0)) {
-		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
-		return -EFSCORRUPTED;
-	}
-	pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
-	bno = be64_to_cpu(*pp);
-
-	/*
-	 * Go down the tree until leaf level is reached, following the first
-	 * pointer (leftmost) at each level.
-	 */
-	while (level-- > 0) {
-		error = xfs_btree_read_bufl(mp, tp, bno, &bp,
-				XFS_BMAP_BTREE_REF, &xfs_bmbt_buf_ops);
-		if (error)
-			goto out;
-		block = XFS_BUF_TO_BLOCK(bp);
-		if (level == 0)
-			break;
-		pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
-		bno = be64_to_cpu(*pp);
-		XFS_WANT_CORRUPTED_GOTO(mp,
-			xfs_verify_fsbno(mp, bno), out_brelse);
-		xfs_trans_brelse(tp, bp);
+		error = -EFSCORRUPTED;
+		goto out;
 	}
 
-	/*
-	 * Here with bp and block set to the leftmost leaf node in the tree.
-	 */
-	i = 0;
-	xfs_iext_first(ifp, &icur);
-
-	/*
-	 * Loop over all leaf nodes.  Copy information to the extent records.
-	 */
-	for (;;) {
-		xfs_bmbt_rec_t	*frp;
-		xfs_fsblock_t	nextbno;
-		xfs_extnum_t	num_recs;
-
-		num_recs = xfs_btree_get_numrecs(block);
-		if (unlikely(i + num_recs > nextents)) {
-			xfs_warn(ip->i_mount,
-				"corrupt dinode %Lu, (btree extents).",
-				(unsigned long long) ip->i_ino);
-			xfs_inode_verifier_error(ip, -EFSCORRUPTED,
-					__func__, block, sizeof(*block),
-					__this_address);
-			error = -EFSCORRUPTED;
-			goto out_brelse;
-		}
-		/*
-		 * Read-ahead the next leaf block, if any.
-		 */
-		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
-		if (nextbno != NULLFSBLOCK)
-			xfs_btree_reada_bufl(mp, nextbno, 1,
-					     &xfs_bmbt_buf_ops);
-		/*
-		 * Copy records into the extent records.
-		 */
-		frp = XFS_BMBT_REC_ADDR(mp, block, 1);
-		for (j = 0; j < num_recs; j++, frp++, i++) {
-			xfs_failaddr_t	fa;
-
-			xfs_bmbt_disk_get_all(frp, &new);
-			fa = xfs_bmap_validate_extent(ip, whichfork, &new);
-			if (fa) {
-				error = -EFSCORRUPTED;
-				xfs_inode_verifier_error(ip, error,
-						"xfs_iread_extents(2)",
-						frp, sizeof(*frp), fa);
-				goto out_brelse;
-			}
-			xfs_iext_insert(ip, &icur, &new, state);
-			trace_xfs_read_extent(ip, &icur, state, _THIS_IP_);
-			xfs_iext_next(ifp, &icur);
-		}
-		xfs_trans_brelse(tp, bp);
-		bno = nextbno;
-		/*
-		 * If we've reached the end, stop.
-		 */
-		if (bno == NULLFSBLOCK)
-			break;
-		error = xfs_btree_read_bufl(mp, tp, bno, &bp,
-				XFS_BMAP_BTREE_REF, &xfs_bmbt_buf_ops);
-		if (error)
-			goto out;
-		block = XFS_BUF_TO_BLOCK(bp);
-	}
+	ir.loaded = 0;
+	xfs_iext_first(ifp, &ir.icur);
+	cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
+	error = xfs_btree_visit_blocks(cur, xfs_iread_bmbt_block,
+			XFS_BTREE_VISIT_RECORDS, &ir);
+	xfs_btree_del_cursor(cur, error);
+	if (error)
+		goto out;
 
-	if (i != XFS_IFORK_NEXTENTS(ip, whichfork)) {
+	if (ir.loaded != XFS_IFORK_NEXTENTS(ip, whichfork)) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
 		error = -EFSCORRUPTED;
 		goto out;
 	}
-	ASSERT(i == xfs_iext_count(ifp));
+	ASSERT(ir.loaded == xfs_iext_count(ifp));
 
 	ifp->if_flags |= XFS_IFEXTENTS;
 	return 0;
-
-out_brelse:
-	xfs_trans_brelse(tp, bp);
 out:
 	xfs_iext_destroy(ifp);
 	return error;