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Subject: Re: [f2fs-dev] [PATCH] f2fs: don't ignore writing pages on fsync
 during checkpoint=disable
To:     Jaegeuk Kim <jaegeuk@kernel.org>, linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
References: <20210823170151.1434772-1-jaegeuk@kernel.org>
From:   Chao Yu <chao@kernel.org>
Message-ID: <baa8a361-1a22-76a0-423d-4378178f7073@kernel.org>
Date:   Tue, 24 Aug 2021 09:08:43 +0800
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On 2021/8/24 1:01, Jaegeuk Kim wrote:
> We must flush dirty pages when calling fsync() during checkpoint=disable.
> Returning zero makes inode being clear, which fails to flush them when
> enabling checkpoint back even by sync_inodes_sb().

Without this patch, file can be persisted via checkpoint=enable as well, my
testcase:

- mount -t f2fs -o checkpoint=disable,checkpoint_nomerge /dev/pmem0 /mnt/f2fs/
- cp file /mnt/f2fs/
- xfs_io /mnt/f2fs/file -c "fdatasync"
- mount -o remount,checkpoint=enable /dev/pmem0 /mnt/f2fs/
- umount /mnt/f2fs
- mount /dev/pmem0 /mnt/f2fs
- md5sum file /mnt/f2fs/file
chksum values are the same.

Am I missing something?

Thanks,