iomap: mark ->iomap_end as optional

No need to implement it for read-only mappings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/iomap.c b/fs/iomap.c
index d9d1f50c36aa..0342254646e3 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -84,8 +84,11 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
          * Now the data has been copied, commit the range we've copied.  This
          * should not fail unless the filesystem has had a fatal error.
          */
-        ret = ops->iomap_end(inode, pos, length, written > 0 ? written : 0,
-                        flags, &iomap);
+        if (ops->iomap_end) {
+                ret = ops->iomap_end(inode, pos, length,
+                                     written > 0 ? written : 0,
+                                     flags, &iomap);
+        }
 
         return written ? written : ret;
 }