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/gc.c b/fs/f2fs/gc.c
index 71462f2e47d4..666518eb7293 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -829,8 +829,8 @@ static int move_data_block(struct inode *inode, block_t bidx,
 	}
 
 write_page:
-	set_page_dirty(fio.encrypted_page);
 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
+	set_page_dirty(fio.encrypted_page);
 	if (clear_page_dirty_for_io(fio.encrypted_page))
 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
 
@@ -924,8 +924,9 @@ static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
 		bool is_dirty = PageDirty(page);
 
 retry:
-		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);