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From: Chris Mason <chris.mason@oracle.com>
To: Roman Mamedov <rm@romanrm.ru>
Cc: dave@jikos.cz, dima <dolenin@parallels.com>, linux-btrfs@vger.kernel.org
Subject: Re: NOCOW + compress-force = bug
Date: Thu, 16 Feb 2012 12:58:15 -0500	[thread overview]
Message-ID: <20120216175815.GM21896@shiny> (raw)
In-Reply-To: <20120216195515.643f4aa7@natsu>

On Thu, Feb 16, 2012 at 07:55:15PM +0600, Roman Mamedov wrote:
> Hello,
> 
> Please be aware that there seems to be a possible problem with using NOCOW
> flag on files situated on a filesystem mounted with compress-force(=lzo, in my
> case).
> 
> Since experimenting with NOCOW, I started regularly hitting this BUG at
> extent-tree.c:5813 
> 
>   5813                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
> 
> I was unable to make netconsole work over a bridged interface, so can only
> post screenshots of this OOPS:
>   http://romanrm.ru/pics/2012/2012-02-16-btrfs-bug-1.jpg
>   http://romanrm.ru/pics/2012/2012-02-16-btrfs-bug-2.jpg
> 
> This happened four times already, and always on snapshot creation (but not
> every case). I have hourly snapshots in crontab, and only one case out of about
> ten fails with this problem. Did not try to deliberately reproduce it yet by
> manually making snapshots very often, etc.

Interesting, NOCOW and compression don't really mix.  We always cow for
compression.  I'll try to reproduce it.

-chris

  parent reply	other threads:[~2012-02-16 17:58 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-13  7:17 Set nodatacow per file? Ralf-Peter Rohbeck
2012-02-13  7:34 ` Chester
2012-02-13  8:10   ` Liu Bo
2012-02-13  7:40 ` dima
2012-02-13  8:09   ` Roman Mamedov
2012-02-13  8:40     ` dima
2012-02-13 13:42     ` dima
2012-02-13 13:51       ` Roman Mamedov
2012-02-13 14:31         ` Dmitry Olenin
2012-02-13 14:10   ` David Sterba
2012-02-13 14:21     ` Timo Witte
2012-02-13 15:10     ` dima
2012-02-16 13:55     ` NOCOW + compress-force = bug Roman Mamedov
2012-02-16 14:30       ` David Sterba
2012-02-16 17:58       ` Chris Mason [this message]
2012-03-13 18:11         ` Jeff Mahoney
2012-03-13 18:36           ` Jeff Mahoney
2012-02-29 15:09     ` Set nodatacow per file? Kyle Gates
2012-02-29 15:34       ` cwillu
2012-02-24  5:22 ` dima
2012-02-27 13:54   ` dima
2012-02-27 22:10     ` Chester
2012-02-28  0:51       ` dima
2012-03-02  3:28         ` dima

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