From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id ED7AB7CA7 for ; Tue, 6 Sep 2016 18:34:23 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay3.corp.sgi.com (Postfix) with ESMTP id 63835AC003 for ; Tue, 6 Sep 2016 16:34:23 -0700 (PDT) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net [150.101.137.143]) by cuda.sgi.com with ESMTP id 2Nd4mfXBGYACXSBh for ; Tue, 06 Sep 2016 16:34:20 -0700 (PDT) Date: Wed, 7 Sep 2016 09:34:18 +1000 From: Dave Chinner Subject: Re: xfs_file_splice_read: possible circular locking dependency detected Message-ID: <20160906233418.GM30056@dastard> References: <723420070.1340881.1472835555274.JavaMail.zimbra@redhat.com> <1832555471.1341372.1472835736236.JavaMail.zimbra@redhat.com> <20160903003919.GI30056@dastard> <58974432.234567.1473198839605.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <58974432.234567.1473198839605.JavaMail.zimbra@redhat.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: CAI Qian Cc: linux-xfs , Linus Torvalds , Al Viro , xfs@oss.sgi.com On Tue, Sep 06, 2016 at 05:53:59PM -0400, CAI Qian wrote: > > > ----- Original Message ----- > > Fundamentally a splice infrastructure problem. If we let splice race > > with hole punch and other fallocate() based extent manipulations to > > avoid this lockdep warning, we allow potential for read or write to > > regions of the file that have been freed. We can live with having > > lockdep complain about this potential deadlock as it is unlikely to > > ever occur in practice. The other option is simply not an acceptible > > solution.... > The problem with living with having this lockdep complain that > it seems once this lockdep happens, it will prevent other complains from > showing up. For example, I have to apply the commit dc3a04d to fix an early > rcu lockdep first during the bisecting. Not my problem. My primary responsibility is to maintain the filesystem integrity and data safety for the hundreds of thousands (millions?) of XFS users: it's their data, and I will always err on the side of safety and integrity. As such I really don't care if there's collateral damage to developer debug tools - user data integrity requirements always come first... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs