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From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Cc:     Jaegeuk Kim <jaegeuk@kernel.org>
Subject: [PATCH 2/2] f2fs: complete checkpoints during remount
Date:   Fri, 19 Aug 2022 16:15:14 -0700
Message-Id: <20220819231514.3609958-2-jaegeuk@kernel.org>
In-Reply-To: <20220819231514.3609958-1-jaegeuk@kernel.org>
References: <20220819231514.3609958-1-jaegeuk@kernel.org>
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Otherwise, pending checkpoints can contribute a race condition to give a
quota warning.

- Thread                      - checkpoint thread
                              add checkpoints to the list
do_remount()
 down_write(&sb->s_umount);
 f2fs_remount()
                              block_operations()
                               down_read_trylock(&sb->s_umount) = 0
 up_write(&sb->s_umount);
                               f2fs_quota_sync()
                                dquot_writeback_dquots()
                                 WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 48ac3de4a533..88879c483805 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2349,6 +2349,9 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 		f2fs_stop_ckpt_thread(sbi);
 		need_restart_ckpt = true;
 	} else {
+		/* flush if the prevous checkpoint, if exists. */
+		f2fs_flush_ckpt_thread(sbi);
+
 		err = f2fs_start_ckpt_thread(sbi);
 		if (err) {
 			f2fs_err(sbi,
-- 
2.37.1.595.g718a3a8f04-goog