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Date: Wed, 3 Sep 2014 19:47:57 +0400
From: Pavel Emelyanov <xemul@parallels.com>
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To: "J. Bruce Fields" <bfields@fieldses.org>
CC: Jeff Layton <jlayton@poochiereds.net>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
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Subject: Re: [PATCH] locks: Ability to test for flock presence on fd
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On 09/03/2014 07:44 PM, J. Bruce Fields wrote:
...

>> Hope this explanation is more clear.
> 
> Thanks, I think I understand.
> 
> Remind me how you figure out which file descriptors point to the same
> file description (struct file)?

We do it with the help of kcmp() syscall:
https://github.com/cyrillos/linux-2.6/commit/951bc60c6a

Thanks,
Pavel