From: "Daniel P. Berrange" <berrange@redhat.com>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: Fam Zheng <famz@redhat.com>, qemu-devel <qemu-devel@nongnu.org>,
qemu block <qemu-block@nongnu.org>
Subject: Re: [Qemu-devel] image locking
Date: Tue, 19 Sep 2017 16:55:23 +0100 [thread overview]
Message-ID: <20170919155523.GU9536@redhat.com> (raw)
In-Reply-To: <a6ad8398-fcef-2d7f-548a-024c54ad2379@virtuozzo.com>
On Tue, Sep 19, 2017 at 06:46:19PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Hi Fam!
>
> I have a question about your image locking series:
>
> Can you please explain, why OFD locking is enabled by default and posix
> locking is not? What is wrong with posix locking, what are the problems?
POSIX locking suffers from a horribly broken design making it practically
impossible to use it reliably, particularly in a threaded program. If
there are two file descriptors open to the same file, closing one FD
will release locks held by the other FD. See more details here:
http://0pointer.de/blog/projects/locking.html
Regards,
Daniel
--
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next prev parent reply other threads:[~2017-09-19 15:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 15:46 [Qemu-devel] image locking Vladimir Sementsov-Ogievskiy
2017-09-19 15:55 ` Daniel P. Berrange [this message]
2017-09-19 16:03 ` [Qemu-devel] [Qemu-block] " Eric Blake
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