Re: [PATCH] ubifs: Add freeze support

From	Amir Goldstein <amir73il@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] ubifs: Add freeze support
Date	2017-05-29 12:10 +0200
Message-ID	<tMpMB-6MM-3@gated-at.bofh.it> (permalink)
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On Mon, May 29, 2017 at 12:00 PM, Richard Weinberger <richard@nod.at> wrote:
> Amir, Hyunchul,
>
> Am 29.05.2017 um 07:40 schrieb Amir Goldstein:
>> On Mon, May 29, 2017 at 7:40 AM, Hyunchul Lee <hyc.lee@gmail.com> wrote:
>>>
>>> and I missed the following case.
>>>
>>> in some embedded systems, clean-up for shutdown should be fast.
>>> during this clean-up, freeze file system to guarantee integrity.
>>> umount with MNT_DETACH is not suitable because of not killing tasks.
>
> more details please, UBIFS is designed to survive a power-cut/reboot/etc.
> at any time. How would it corrupt?
>
>> Interesting point. It seems that good old "sync; reboot" does not cut
>> it anymore.
>> Not even emergency remount read-only sysrq trigger.
>>
>> Some of you may have been following this thread on fsdevel:
>> https://www.spinics.net/lists/linux-xfs/msg06953.html
>>
>> Probably less have been following this longer thread on xfs list:
>> https://www.spinics.net/lists/linux-xfs/msg06883.html
>
> Well, UBIFS is a bit different.
> The UBIFS journal is not an add-on feature, you have to replay it in
> any case. Otherwise you're facing corrupted data.

Yes, I suppose you are right.
I guess there is no equivalent of mount -oro,{norecovery,noload} for
ubifs.

I don't know the ubifs journal implementation details.
Can ubifs_run_commit() when writers are frozen contribute to
shorter journal replay time after boot with some workloads?

Amir.

Thread

[PATCH] ubifs: Add freeze support Hyunchul Lee <hyc.lee@gmail.com> - 2017-05-26 01:40 +0200
  Re: [PATCH] ubifs: Add freeze support Richard Weinberger <richard@nod.at> - 2017-05-26 12:00 +0200
    Re: [PATCH] ubifs: Add freeze support Christoph Hellwig <hch@infradead.org> - 2017-05-27 10:20 +0200
    Re: [PATCH] ubifs: Add freeze support Hyunchul Lee <hyc.lee@gmail.com> - 2017-05-29 03:20 +0200
      Re: [PATCH] ubifs: Add freeze support Hyunchul Lee <hyc.lee@gmail.com> - 2017-05-29 06:50 +0200
        Re: [PATCH] ubifs: Add freeze support Amir Goldstein <amir73il@gmail.com> - 2017-05-29 07:50 +0200
          Re: [PATCH] ubifs: Add freeze support Richard Weinberger <richard@nod.at> - 2017-05-29 11:10 +0200
            Re: [PATCH] ubifs: Add freeze support Amir Goldstein <amir73il@gmail.com> - 2017-05-29 12:10 +0200
              Re: [PATCH] ubifs: Add freeze support Richard Weinberger <richard@nod.at> - 2017-05-29 12:20 +0200
                Re: [PATCH] ubifs: Add freeze support Amir Goldstein <amir73il@gmail.com> - 2017-05-29 13:50 +0200
  Re: [PATCH] ubifs: Add freeze support Christoph Hellwig <hch@infradead.org> - 2017-05-27 10:30 +0200
    Re: [PATCH] ubifs: Add freeze support Hyunchul Lee <hyc.lee@gmail.com> - 2017-05-29 02:50 +0200
      Re: [PATCH] ubifs: Add freeze support Hyunchul Lee <hyc.lee@gmail.com> - 2017-05-29 04:30 +0200
        Re: [PATCH] ubifs: Add freeze support Richard Weinberger <richard@nod.at> - 2017-05-29 10:50 +0200
          Re: [PATCH] ubifs: Add freeze support Hyunchul Lee <hyc.lee@gmail.com> - 2017-05-30 04:40 +0200
            Re: [PATCH] ubifs: Add freeze support Richard Weinberger <richard@nod.at> - 2017-05-30 10:00 +0200

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