1 files changed, 91 insertions, 73 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 532c4aab20f2..69bf8d868b64 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5518,6 +5518,88 @@ out_error:
 }
 
 /*
+ * Shift a single extent.
+ */
+STATIC int
+xfs_bmse_shift_one(
+	struct xfs_inode		*ip,
+	int				whichfork,
+	xfs_fileoff_t			offset_shift_fsb,
+	int				*current_ext,
+	struct xfs_bmbt_rec_host	*gotp,
+	struct xfs_btree_cur		*cur,
+	int				*logflags)
+{
+	struct xfs_ifork		*ifp;
+	xfs_fileoff_t			startoff;
+	struct xfs_bmbt_rec_host	*leftp;
+	struct xfs_bmbt_irec		got;
+	struct xfs_bmbt_irec		left;
+	int				error;
+	int				i;
+
+	ifp = XFS_IFORK_PTR(ip, whichfork);
+
+	xfs_bmbt_get_all(gotp, &got);
+	startoff = got.br_startoff - offset_shift_fsb;
+
+	/*
+	 * If this is the first extent in the file, make sure there's enough
+	 * room at the start of the file and jump right to the shift as there's
+	 * no left extent to merge.
+	 */
+	if (*current_ext == 0) {
+		if (got.br_startoff < offset_shift_fsb)
+			return -EINVAL;
+		goto shift_extent;
+	}
+
+	/* grab the left extent and check for a large enough hole */
+	leftp = xfs_iext_get_ext(ifp, *current_ext - 1);
+	xfs_bmbt_get_all(leftp, &left);
+
+	if (startoff < left.br_startoff + left.br_blockcount)
+		return -EINVAL;
+
+	/* check whether to merge the extent or shift it down */
+	if (!xfs_bmse_can_merge(&left, &got, offset_shift_fsb))
+		goto shift_extent;
+
+	return xfs_bmse_merge(ip, whichfork, offset_shift_fsb, *current_ext,
+			      gotp, leftp, cur, logflags);
+
+shift_extent:
+	/*
+	 * Increment the extent index for the next iteration, update the start
+	 * offset of the in-core extent and update the btree if applicable.
+	 */
+	(*current_ext)++;
+	xfs_bmbt_set_startoff(gotp, startoff);
+	*logflags |= XFS_ILOG_CORE;
+	if (!cur) {
+		*logflags |= XFS_ILOG_DEXT;
+		return 0;
+	}
+
+	error = xfs_bmbt_lookup_eq(cur, got.br_startoff, got.br_startblock,
+				   got.br_blockcount, &i);
+	if (error)
+		return error;
+	XFS_WANT_CORRUPTED_GOTO(i == 1, out_error);
+
+	got.br_startoff = startoff;
+	error = xfs_bmbt_update(cur, got.br_startoff, got.br_startblock,
+				got.br_blockcount, got.br_state);
+	if (error)
+		return error;
+
+	return 0;
+
+out_error:
+	return error;
+}
+
+/*
  * Shift extent records to the left to cover a hole.
  *
  * The maximum number of extents to be shifted in a single operation is
@@ -5541,16 +5623,12 @@ xfs_bmap_shift_extents(
 {
 	struct xfs_btree_cur		*cur = NULL;
 	struct xfs_bmbt_rec_host	*gotp;
-	struct xfs_bmbt_rec_host	*leftp;
 	struct xfs_bmbt_irec            got;
-	struct xfs_bmbt_irec		left;
 	struct xfs_mount		*mp = ip->i_mount;
 	struct xfs_ifork		*ifp;
 	xfs_extnum_t			nexts = 0;
 	xfs_extnum_t			current_ext;
-	xfs_fileoff_t			startoff;
 	int				error = 0;
-	int				i;
 	int				whichfork = XFS_DATA_FORK;
 	int				logflags = 0;
 	int				total_extents;
@@ -5599,16 +5677,6 @@ xfs_bmap_shift_extents(
 		*done = 1;
 		goto del_cursor;
 	}
-	xfs_bmbt_get_all(gotp, &got);
-
-	/*
-	 * If the first extent is shifted, offset_shift_fsb cannot be larger
-	 * than the starting offset of the first extent.
-	 */
-	if (current_ext == 0 && got.br_startoff < offset_shift_fsb) {
-		error = -EINVAL;
-		goto del_cursor;
-	}
 
 	/*
 	 * There may be delalloc extents in the data fork before the range we
@@ -5617,75 +5685,25 @@ xfs_bmap_shift_extents(
 	 */
 	total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
 	while (nexts++ < num_exts && current_ext < total_extents) {
-		startoff = got.br_startoff - offset_shift_fsb;
-
-		/* grab the left extent and check for a potential merge */
-		if (current_ext > 0) {
-			leftp = xfs_iext_get_ext(ifp, current_ext - 1);
-			xfs_bmbt_get_all(leftp, &left);
-
-			/* make sure hole is large enough for shift */
-			if (startoff < left.br_startoff + left.br_blockcount) {
-				error = -EINVAL;
-				goto del_cursor;
-			}
-
-			if (xfs_bmse_can_merge(&left, &got, offset_shift_fsb)) {
-				error = xfs_bmse_merge(ip, whichfork,
-						offset_shift_fsb, current_ext, gotp,
-						leftp, cur, &logflags);
-				if (error)
-					goto del_cursor;
-
-				/*
-				 * The extent was merged so adjust the extent
-				 * index and move onto the next.
-				 */
-				current_ext--;
-				goto next;
-			}
-		}
-
-		/*
-		 * We didn't merge the extent so do the shift. Update the start
-		 * offset in the in-core extent and btree, if necessary.
-		 */
-		xfs_bmbt_set_startoff(gotp, startoff);
-		logflags |= XFS_ILOG_CORE;
-		if (cur) {
-			error = xfs_bmbt_lookup_eq(cur, got.br_startoff,
-						   got.br_startblock,
-						   got.br_blockcount,
-						   &i);
-			if (error)
-				goto del_cursor;
-			XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
-
-			got.br_startoff = startoff;
-			error = xfs_bmbt_update(cur, got.br_startoff,
-						got.br_startblock,
-						got.br_blockcount,
-						got.br_state);
-			if (error)
-				goto del_cursor;
-		} else {
-			logflags |= XFS_ILOG_DEXT;
-		}
+		error = xfs_bmse_shift_one(ip, whichfork, offset_shift_fsb,
+					&current_ext, gotp, cur, &logflags);
+		if (error)
+			goto del_cursor;
 
-next:
 		/* update total extent count and grab the next record */
 		total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
-		if (++current_ext >= total_extents)
+		if (current_ext >= total_extents)
 			break;
 		gotp = xfs_iext_get_ext(ifp, current_ext);
-		xfs_bmbt_get_all(gotp, &got);
 	}
 
 	/* Check if we are done */
-	if (current_ext == total_extents)
+	if (current_ext == total_extents) {
 		*done = 1;
-	else if (next_fsb)
+	} else if (next_fsb) {
+		xfs_bmbt_get_all(gotp, &got);
 		*next_fsb = got.br_startoff;
+	}
 
 del_cursor:
 	if (cur)