f2fs: don't use GFP_ZERO for page caches

Related to https://lkml.org/lkml/2018/4/8/661

Sometimes, we need to write meta data to new allocated block address,
then we will allocate a zeroed page in inner inode's address space, and
fill partial data in it, and leave other place with zero value which means
some fields are initial status.

There are two inner inodes (meta inode and node inode) setting __GFP_ZERO,
I have just checked them, for both of them, we can avoid using __GFP_ZERO,
and do initialization by ourselves to avoid unneeded/redundant zeroing
from mm.

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

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 3d3a1f6b21a1..8fc55d42ba25 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -100,8 +100,10 @@ repeat:
 	 * readonly and make sure do not write checkpoint with non-uptodate
 	 * meta page.
 	 */
-	if (unlikely(!PageUptodate(page)))
+	if (unlikely(!PageUptodate(page))) {
+		memset(page_address(page), 0, PAGE_SIZE);
 		f2fs_stop_checkpoint(sbi, false);
+	}
 out:
 	return page;
 }