[PATCH 8/9] xfs: factor out a xfs_zoned_fill_srcmap helper

[Christoph Hellwig <hch@lst.de>]

The code filling the srcmap in xfs_zoned_buffered_write_iomap_begin isn't
terribly complicated, but fairly deeply indented and will become a bit
more complex soon.  Factor it into a helper and add some comments.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_iomap.c | 53 ++++++++++++++++++++++++++++++----------------
 1 file changed, 35 insertions(+), 18 deletions(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 7c6238fed61e..7bc17f179be7 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1588,6 +1588,37 @@ xfs_bmapi_reserve_delalloc(
 	return error;
 }
 
+static int
+xfs_zoned_fill_srcmap(
+	struct xfs_inode	*ip,
+	xfs_fileoff_t		offset_fsb,
+	xfs_fileoff_t		*end_fsb,
+	unsigned		flags,
+	struct iomap		*srcmap)
+{
+	struct xfs_bmbt_irec	smap;
+	struct xfs_iext_cursor	scur;
+
+	if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &scur, &smap))
+		smap.br_startoff = *end_fsb; /* fake hole until EOF */
+	if (smap.br_startoff > offset_fsb) {
+		/*
+		 * There is a hole at @offset_fsb.  Only map until the end of
+		 * the of it.
+		 */
+		*end_fsb = min(*end_fsb, smap.br_startoff);
+		return 0;
+	}
+
+	/*
+	 * There is a data fork mapping, only map until the end of it.
+	 */
+	*end_fsb = min(*end_fsb, smap.br_startoff + smap.br_blockcount);
+	xfs_trim_extent(&smap, offset_fsb, *end_fsb - offset_fsb);
+	return xfs_bmbt_to_iomap(ip, srcmap, &smap, flags, 0,
+			xfs_iomap_inode_sequence(ip, 0));
+}
+
 static int
 xfs_zoned_buffered_write_iomap_begin(
 	struct inode		*inode,
@@ -1655,24 +1686,10 @@ xfs_zoned_buffered_write_iomap_begin(
 	if (!IS_ALIGNED(offset, mp->m_sb.sb_blocksize) ||
 	    !IS_ALIGNED(offset + count, mp->m_sb.sb_blocksize) ||
 	    (flags & IOMAP_ZERO)) {
-		struct xfs_bmbt_irec	smap;
-		struct xfs_iext_cursor	scur;
-
-		if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &scur,
-				&smap))
-			smap.br_startoff = end_fsb; /* fake hole until EOF */
-		if (smap.br_startoff > offset_fsb) {
-			end_fsb = min(end_fsb, smap.br_startoff);
-		} else {
-			end_fsb = min(end_fsb,
-				smap.br_startoff + smap.br_blockcount);
-			xfs_trim_extent(&smap, offset_fsb,
-					end_fsb - offset_fsb);
-			error = xfs_bmbt_to_iomap(ip, srcmap, &smap, flags, 0,
-					xfs_iomap_inode_sequence(ip, 0));
-			if (error)
-				goto out_unlock;
-		}
+		error = xfs_zoned_fill_srcmap(ip, offset_fsb, &end_fsb, flags,
+				srcmap);
+		if (error)
+			goto out_unlock;
 	}
 
 	if (!ip->i_cowfp)
-- 
2.53.0