From: Sergei Poselenov <sposelenov@emcraft.com>
To: Richard Weinberger <richard@nod.at>
Cc: linux-mtd <linux-mtd@lists.infradead.org>
Subject: Re: UBIFS: file data corruption during the power cut-off test
Date: Sun, 09 Jun 2019 12:59:09 +0300 [thread overview]
Message-ID: <ac7d203471da8db3a148c207b586cae919304307.camel@emcraft.com> (raw)
In-Reply-To: <1957000286.85744.1560070414116.JavaMail.zimbra@nod.at>
On Sun, 2019-06-09 at 10:53 +0200, Richard Weinberger wrote:
> ----- Ursprüngliche Mail -----
> > Now, the question: why are these 512 bytes of zeros in test4?
> >
> > Extrapolating to a real use case, consider a system writing a log
> > file
> > to the UBI partition. Power cutoff, recovery, and we have a garbage
> > at
> > the end of the log file. Is this expected?
>
> Well, zero bytes are not garbage. ;)
I've seen some data in the last 512 bytes as well.
> But yes, this is is expected. In your case, I guess, the inode size
> does not match exactly what is present on flash.
> So the file size is 512 bytes too large, if you read too far, 0x0
> bytes are returned.
> During journal replay UBIFS tries to fixup file lengths but is
> approach
> does not work in all cases perfectly.
>
> This case is actually documented, please see:
> http://www.linux-mtd.infradead.org/doc/ubifs.html#L_sync_semantics
>
Thank you for the pointer. I'll look.
Regards,
Sergei
> Thanks,
> //richard
>
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next prev parent reply other threads:[~2019-06-09 9:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 9:10 UBIFS: file data corruption during the power cut-off test Sergei Poselenov
2019-06-06 14:55 ` Richard Weinberger
2019-06-06 18:08 ` Sergei Poselenov
2019-06-06 18:13 ` Richard Weinberger
2019-06-07 14:23 ` Sergei Poselenov
2019-06-07 16:01 ` Steve deRosier
2019-06-09 8:32 ` Sergei Poselenov
2019-06-09 15:25 ` Steve deRosier
2019-06-07 16:02 ` Richard Weinberger
2019-06-08 6:42 ` Sergei Poselenov
2019-06-08 8:46 ` Richard Weinberger
2019-06-09 8:18 ` Sergei Poselenov
2019-06-09 8:53 ` Richard Weinberger
2019-06-09 9:59 ` Sergei Poselenov [this message]
2019-06-09 10:00 ` Richard Weinberger
2019-06-15 7:26 ` Sergei Poselenov
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