From: Anthony Liguori <anthony@codemonkey.ws>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: KVM list <kvm@vger.kernel.org>, Kevin Wolf <kwolf@redhat.com>
Subject: Re: JFYI: ext4 bug triggerable by kvm
Date: Mon, 16 Aug 2010 09:43:09 -0500 [thread overview]
Message-ID: <4C694E7D.3060600@codemonkey.ws> (raw)
In-Reply-To: <4C694483.5010903@msgid.tls.msk.ru>
On 08/16/2010 09:00 AM, Michael Tokarev wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=16165
>
> When a (raw) guest image is placed on an ext4 filesystem,
> it is possible to get data corruption, now due to ext4
> bug, not kvm bug.
>
Yeah, there appears to be a few O_DIRECT related issues with ext4.
AFAIK, a preallocated raw image should be safe though which is probably
the only time you should use O_DIRECT.
> Also, ext4 is _very_ slow on O_SYNC writes (which is
> used in kvm with default cache).
>
Yeah, we probably need to switch to sync_file_range() to avoid the
journal commit on every write.
Regards,
Anthony Liguori
> JFYI.
>
> /mjt
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next prev parent reply other threads:[~2010-08-16 14:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-16 14:00 JFYI: ext4 bug triggerable by kvm Michael Tokarev
2010-08-16 14:43 ` Anthony Liguori [this message]
2010-08-16 18:42 ` Christoph Hellwig
2010-08-16 20:34 ` Anthony Liguori
2010-08-17 9:07 ` Christoph Hellwig
2010-08-17 9:23 ` Avi Kivity
2010-08-17 11:17 ` Christoph Hellwig
2010-08-17 12:56 ` Anthony Liguori
2010-08-17 13:07 ` Christoph Hellwig
2010-08-17 14:20 ` Anthony Liguori
2010-08-17 14:28 ` Christoph Hellwig
2010-08-17 14:39 ` Anthony Liguori
2010-08-17 14:45 ` Christoph Hellwig
2010-08-17 14:53 ` Avi Kivity
2010-08-17 14:54 ` Anthony Liguori
2010-08-17 15:01 ` Avi Kivity
2010-08-17 15:02 ` Christoph Hellwig
2010-08-17 14:40 ` Michael Tokarev
2010-08-17 14:44 ` Anthony Liguori
2010-08-17 14:46 ` Christoph Hellwig
2010-08-17 14:57 ` Anthony Liguori
2010-08-17 14:59 ` Avi Kivity
2010-08-17 15:04 ` Christoph Hellwig
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