f2fs: fix to reorder set_page_dirty and wait_on_page_writeback

This patch reorders flow from

- update page
- set_page_dirty
- wait_on_page_writeback

to

- wait_on_page_writeback
- update page
- set_page_dirty

The reason is:
- set_page_dirty will increase reference of dirty page, the reference
should be cleared before wait_on_page_writeback to keep its consistency.
- some devices need stable page during page writebacking, so we
should not change page's data.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index a63ce35a988f..f23bc3ebbdec 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1600,10 +1600,11 @@ int f2fs_move_node_page(struct page *node_page, int gc_type)
 			.for_reclaim = 0,
 		};
 
-		set_page_dirty(node_page);
 		f2fs_wait_on_page_writeback(node_page, NODE, true);
-
 		f2fs_bug_on(F2FS_P_SB(node_page), PageWriteback(node_page));
+
+		set_page_dirty(node_page);
+
 		if (!clear_page_dirty_for_io(node_page)) {
 			err = -EAGAIN;
 			goto out_page;