FAILED: patch "[PATCH] f2fs: flush data when enabling checkpoint back" failed to apply to 5.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b0ff4fe746fd028eef920ddc8c7b0361c1ede6ec Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Tue, 26 Jan 2021 17:00:42 -0800
Subject: [PATCH] f2fs: flush data when enabling checkpoint back

During checkpoint=disable period, f2fs bypasses all the synchronous IOs such as
sync and fsync. So, when enabling it back, we must flush all of them in order
to keep the data persistent. Otherwise, suddern power-cut right after enabling
checkpoint will cause data loss.

Fixes: 4354994f097d ("f2fs: checkpoint disabling")
Cc: stable@vger.kernel.org
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index fc343243799c..429bc00af440 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1892,6 +1892,9 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 
 static void f2fs_enable_checkpoint(struct f2fs_sb_info *sbi)
 {
+	/* we should flush all the data to keep data consistency */
+	sync_inodes_sb(sbi->sb);
+
 	down_write(&sbi->gc_lock);
 	f2fs_dirty_to_prefree(sbi);