From: Richard Weinberger <richard@nod.at>
To: Sergei Poselenov <sposelenov@emcraft.com>
Cc: linux-mtd <linux-mtd@lists.infradead.org>
Subject: Re: UBIFS: file data corruption during the power cut-off test
Date: Sun, 9 Jun 2019 10:53:34 +0200 (CEST) [thread overview]
Message-ID: <1957000286.85744.1560070414116.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <a43eb232a51b7d0c95623de9403158c290163237.camel@emcraft.com>
----- 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. ;)
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
Thanks,
//richard
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next prev parent reply other threads:[~2019-06-09 8:53 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 [this message]
2019-06-09 9:59 ` Sergei Poselenov
2019-06-09 10:00 ` Richard Weinberger
2019-06-15 7:26 ` Sergei Poselenov
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