Btrfs: fix wrong write range for filemap_fdatawrite_range()

filemap_fdatawrite_range() expect the third arg to be @end
not @len, fix it.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/inode.c

@@ -7533,7 +7533,8 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 	count = iov_iter_count(iter);
 	if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
 		     &BTRFS_I(inode)->runtime_flags))
-		filemap_fdatawrite_range(inode->i_mapping, offset, count);
+		filemap_fdatawrite_range(inode->i_mapping, offset,
+					 offset + count - 1);
 
 	if (rw & WRITE) {
 		/*