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Re: [Qemu-devel] image locking
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] image locking |
Date: |
Tue, 19 Sep 2017 16:55:23 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
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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