From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Petr Vandrovec" <VANDROVE@vc.cvut.cz>
Subject: Re: Problem using mandatory locks (other apps can read/dele
Date: Wed, 17 Apr 2002 11:53:52 +0200
Sender: linux-fsdevel-owner@vger.kernel.org
Message-ID: <29CDCA24824@vcnet.vc.cvut.cz>
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Cc: linux-fsdevel@vger.kernel.org
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To: "E. Abbink" <esger@bumblebeast.com>
List-Id: linux-fsdevel.vger.kernel.org

On 17 Apr 02 at 12:22, E. Abbink wrote:
> reading with a mandatory file lock set:
> 
> display       -   reads & displays image fine, seems to break lock 

Did you tried 'strace'? display probably tries to mmap() it, and
for some strange reason your kernel allows mmap on file marked for
mandatory locking. There was some discussion about disabling mmap
for them, but I have no idea what current state is, and what other
platforms do.
                                        Petr Vandrovec
                                        vandrove@vc.cvut.cz