[PATCH 1/2] iomap: don't bother unsharing delalloc extents

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

If unshare encounters a delalloc reservation in the srcmap, that means
that the file range isn't shared because delalloc reservations cannot be
reflinked.  Therefore, don't try to unshare them.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/iomap/buffered-io.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 11ea747228aee..c1c559e0cc07c 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1321,7 +1321,7 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
 		return length;
 
 	/*
-	 * Don't bother with holes or unwritten extents.
+	 * Don't bother with delalloc reservations, holes or unwritten extents.
 	 *
 	 * Note that we use srcmap directly instead of iomap_iter_srcmap as
 	 * unsharing requires providing a separate source map, and the presence
@@ -1330,6 +1330,7 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
 	 * fork for XFS.
 	 */
 	if (iter->srcmap.type == IOMAP_HOLE ||
+	    iter->srcmap.type == IOMAP_DELALLOC ||
 	    iter->srcmap.type == IOMAP_UNWRITTEN)
 		return length;