xfs: fix xfs_reflink_unshare usage of filemap_write_and_wait_range

The final parameter of filemap_write_and_wait_range is the end of the
range to flush, not the length of the range to flush.

Fixes: 46afb06 ("xfs: only flush the unshared range in xfs_reflink_unshare")
Signed-off-by: Darrick J. Wong <[email protected]>
Reviewed-by: Chandan Babu R <[email protected]>
Reviewed-by: Brian Foster <[email protected]>

Author: Darrick J. Wong

fs/xfs/xfs_reflink.c

@@ -1522,7 +1522,8 @@ xfs_reflink_unshare(
 	if (error)
 		goto out;
 
-	error = filemap_write_and_wait_range(inode->i_mapping, offset, len);
+	error = filemap_write_and_wait_range(inode->i_mapping, offset,
+			offset + len - 1);
 	if (error)
 		goto out;