Received: with ECARTIS (v1.0.0; list xfs); Mon, 08 Jan 2007 23:57:06 -0800 (PST) Received: from fallback.mail.elte.hu (fallback.mail.elte.hu [157.181.151.13]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l097uwqw016475 for ; Mon, 8 Jan 2007 23:57:01 -0800 Received: from mx2.mail.elte.hu ([157.181.151.9]) by fallback.mail.elte.hu with esmtp (Exim) id 1H4Ak5-00074g-52 from for ; Tue, 09 Jan 2007 07:45:53 +0100 Received: from elvis.elte.hu ([157.181.1.14]) by mx2.mail.elte.hu with esmtp (Exim) id 1H4Aj5-00062Q-0v from ; Tue, 09 Jan 2007 07:44:51 +0100 Received: by elvis.elte.hu (Postfix, from userid 1004) id 6242D3E243E; Tue, 9 Jan 2007 07:44:11 +0100 (CET) Date: Tue, 9 Jan 2007 07:41:13 +0100 From: Ingo Molnar To: Andrew Morton Cc: David Chinner , linux-kernel Mailing List , xfs@oss.sgi.com, Arjan van de Ven , Peter Zijlstra Subject: Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock() Message-ID: <20070109064113.GB5569@elte.hu> References: <20070104001420.GA32440@m.safari.iki.fi> <20070107213734.GS44411608@melbourne.sgi.com> <20070108155636.a68dce33.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070108155636.a68dce33.akpm@osdl.org> User-Agent: Mutt/1.4.2.2i Received-SPF: softfail (mx2: transitioning domain of elte.hu does not designate 157.181.1.14 as permitted sender) client-ip=157.181.1.14; envelope-from=mingo@elte.hu; helo=elvis.elte.hu; X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.6 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.6 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] X-archive-position: 10225 X-ecartis-version: Ecartis v1.0.0 Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com X-original-sender: mingo@elte.hu Precedence: bulk X-list: xfs Content-Length: 619 Lines: 17 * Andrew Morton wrote: > > Revert bd_mount_mutex back to a semaphore so that xfs_freeze -f > > /mnt/newtest; xfs_freeze -u /mnt/newtest works safely and doesn't > > produce lockdep warnings. > > Sad. The alternative would be to implement > mutex_unlock_dont_warn_if_a_different_task_did_it(). Ingo? Possible? i'd like to avoid it as much as i'd like to avoid having to add spin_unlock_dont_warn_if_a_different_task_did_it(). Unlocking by a different task is usually a sign of messy locking and bugs lurking. Is it really true that XFS's use of bd_mount_mutex is safe and justified? Ingo