ext4: remove buffer_uninit handling

There isn't any need for setting BH_Uninit on buffers anymore.  It was
only used to signal we need to mark io_end as needing extent
conversion in add_bh_to_extent() but now we can mark the io_end
directly when mapping extent.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5939a47..736d164 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2047,8 +2047,6 @@
 					clear_buffer_delay(bh);
 					bh->b_blocknr = pblock++;
 				}
-				if (mpd->map.m_flags & EXT4_MAP_UNINIT)
-					set_buffer_uninit(bh);
 				clear_buffer_unwritten(bh);
 			} while (++lblk < blocks &&
 				 (bh = bh->b_this_page) != head);
@@ -2110,6 +2108,8 @@
 	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
 	if (err < 0)
 		return err;
+	if (map->m_flags & EXT4_MAP_UNINIT)
+		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
 
 	BUG_ON(map->m_len == 0);
 	if (map->m_flags & EXT4_MAP_NEW) {