[PATCH v2 03/10] xfs: make xfs_bmapi_convert_delalloc() to allocate the target offset

[Zhang Yi <yi.zhang@xxxxxxxxxxxxxxx>]

From: Zhang Yi <yi.zhang@xxxxxxxxxx>

Since xfs_bmapi_convert_delalloc() only attempts to allocate the entire
delalloc extent and require multiple invocations to allocate the target
offset. So xfs_convert_blocks() add a loop to do this job and we call it
in the write back path, but xfs_convert_blocks() isn't a common helper.
Let's do it in xfs_bmapi_convert_delalloc(), preparing for the post EOF
delalloc blocks converting in the buffered write begin path.

Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_bmap.c | 34 ++++++++++++++++++++++++++++++++--
 fs/xfs/xfs_aops.c        | 15 +--------------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 07dc35de8ce5..042e8d3ab0ba 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4516,8 +4516,8 @@ xfs_bmapi_write(
  * invocations to allocate the target offset if a large enough physical extent
  * is not available.
  */
-int
-xfs_bmapi_convert_delalloc(
+static int
+__xfs_bmapi_convert_delalloc(
 	struct xfs_inode	*ip,
 	int			whichfork,
 	xfs_off_t		offset,
@@ -4648,6 +4648,36 @@ xfs_bmapi_convert_delalloc(
 	return error;
 }
 
+/*
+ * Pass in a dellalloc extent and convert it to real extents, return the real
+ * extent that maps offset_fsb in iomap.
+ */
+int
+xfs_bmapi_convert_delalloc(
+	struct xfs_inode	*ip,
+	int			whichfork,
+	loff_t			offset,
+	struct iomap		*iomap,
+	unsigned int		*seq)
+{
+	int			error;
+
+	/*
+	 * Attempt to allocate whatever delalloc extent currently backs offset
+	 * and put the result into iomap.  Allocate in a loop because it may
+	 * take several attempts to allocate real blocks for a contiguous
+	 * delalloc extent if free space is sufficiently fragmented.
+	 */
+	do {
+		error = __xfs_bmapi_convert_delalloc(ip, whichfork, offset,
+					iomap, seq);
+		if (error)
+			return error;
+	} while (iomap->offset + iomap->length <= offset);
+
+	return 0;
+}
+
 int
 xfs_bmapi_remap(
 	struct xfs_trans	*tp,
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 813f85156b0c..376ec0993943 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -248,7 +248,6 @@ xfs_convert_blocks(
 	int			whichfork,
 	loff_t			offset)
 {
-	int			error;
 	unsigned		*seq;
 
 	if (whichfork == XFS_COW_FORK)
@@ -256,20 +255,8 @@ xfs_convert_blocks(
 	else
 		seq = &XFS_WPC(wpc)->data_seq;
 
-	/*
-	 * Attempt to allocate whatever delalloc extent currently backs offset
-	 * and put the result into wpc->iomap.  Allocate in a loop because it
-	 * may take several attempts to allocate real blocks for a contiguous
-	 * delalloc extent if free space is sufficiently fragmented.
-	 */
-	do {
-		error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
+	return xfs_bmapi_convert_delalloc(ip, whichfork, offset,
 				&wpc->iomap, seq);
-		if (error)
-			return error;
-	} while (wpc->iomap.offset + wpc->iomap.length <= offset);
-
-	return 0;
 }
 
 static int
-- 
2.39.2