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Subject: Re: [PATCH v3] f2fs: checkpoint disabling
To:     Daniel Rosenberg <drosen@google.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        <linux-f2fs-devel@lists.sourceforge.net>
CC:     <linux-kernel@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-fsdevel@vger.kernel.org>, <kernel-team@android.com>
References: <20180807234843.129387-1-drosen@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <b156678d-56e6-a46b-c7a6-00f4bc2c4b3d@huawei.com>
Date:   Fri, 10 Aug 2018 16:40:53 +0800
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Hi Daniel,

On 2018/8/8 7:48, Daniel Rosenberg wrote:
> This adds a lightweight non-persistent snapshotting scheme to f2fs.
> 
> To use, mount with the option checkpoint=disable, and to return to
> normal operation, remount with checkpoint=enable. If the filesystem
> is shut down before remounting with checkpoint=enable, it will revert
> back to its apparent state when it was first mounted with
> checkpoint=disable. This is useful for situations where you wish to be
> able to roll back the state of the disk in case of some critical
> failure.

When filesystem is full, statfs shown abnormally as below:

/dev/zram0       2095104 -17177769548 17179864652    - /mnt/f2fs

I guess it's related to this patch, could you have a look at this?

Thanks,