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, 2 insertions, 1 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 204d31e58967..e2e971e89b2d 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -387,8 +387,9 @@ static int __f2fs_commit_inmem_pages(struct inode *inode)
 		if (page->mapping == inode->i_mapping) {
 			trace_f2fs_commit_inmem_page(page, INMEM);
 
-			set_page_dirty(page);
 			f2fs_wait_on_page_writeback(page, DATA, true);
+
+			set_page_dirty(page);
 			if (clear_page_dirty_for_io(page)) {
 				inode_dec_dirty_pages(inode);
 				f2fs_remove_dirty_inode(inode);