Re: [Qemu-block] [Qemu-devel] image locking

[Daniel P. Berrange]

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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