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From: Hyunchul Lee <hyc.lee@gmail.com>
To: Richard Weinberger <richard@nod.at>
Cc: Artem Bityutskiy <dedekind1@gmail.com>,
	adrian.hunter@intel.com, linux-kernel@vger.kernel.org,
	kernel-team@lge.com, linux-mtd@lists.infradead.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] ubifs: Add freeze support
Date: Mon, 29 May 2017 13:40:59 +0900	[thread overview]
Message-ID: <20170529044059.GA12991@sebu> (raw)
In-Reply-To: <20170529011834.GB10215@sebu>


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.

On Mon, May 29, 2017 at 10:18:34AM +0900, Hyunchul Lee wrote:
> Hi, Richard.
> 
> On Fri, May 26, 2017 at 11:52:42AM +0200, Richard Weinberger wrote:
> > Hyunchul,
> > 
> > Am 26.05.2017 um 01:30 schrieb Hyunchul Lee:
> > > From: Hyunchul Lee <cheol.lee@lge.com>
> > > 
> > > for un/freeze support, implement freeze_super and un/freeze_fs
> > > of super_operations.
> > > ubifs_freeze_super just calls freeze_super. because freeze_super always
> > > succeeds if file system is read-only,  UBIFS errors should be checked.
> > > if there are errors, UBIFS is switched to read-only mode.
> > > ubifs_freeze_fs runs commit if TNC/LPT isn't clean. though all writes
> > > are blocked and sync_fs is called before, if commit alreay was started
> > > before writes are blocked, TNC/LPT might have dirty COW nodes.
> > 
> > you explain how you implement that feature, but not why.
> > What is the use-case?
> > I always thought this interface is only being used by LVM.
> 
> Sorry, I forgot this. I implement this to make a backup of some files, and
> support fsfreeze utility and SysRq's freeze/thaw commmand.
> 
> > 
> > Thanks,
> > //richard
> > 
> > ______________________________________________________
> > Linux MTD discussion mailing list
> > http://lists.infradead.org/mailman/listinfo/linux-mtd/
> 
> -- 
> 
> Thanks,
> Hyunchul
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

-- 

Thanks,
Hyunchul

  reply	other threads:[~2017-05-29  4:41 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-25 23:30 [PATCH] ubifs: Add freeze support Hyunchul Lee
2017-05-26  9:52 ` Richard Weinberger
2017-05-27  8:18   ` Christoph Hellwig
2017-05-29  1:18   ` Hyunchul Lee
2017-05-29  4:40     ` Hyunchul Lee [this message]
2017-05-29  5:40       ` Amir Goldstein
2017-05-29  9:00         ` Richard Weinberger
2017-05-29 10:04           ` Amir Goldstein
2017-05-29 10:17             ` Richard Weinberger
2017-05-29 11:44               ` Amir Goldstein
2017-05-27  8:23 ` Christoph Hellwig
2017-05-29  0:43   ` Hyunchul Lee
2017-05-29  2:24     ` Hyunchul Lee
2017-05-29  8:42       ` Richard Weinberger
2017-05-30  2:37         ` Hyunchul Lee
2017-05-30  7:51           ` Richard Weinberger

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