From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sunil Mushran Date: Wed, 13 Jan 2010 11:14:48 -0800 Subject: [Ocfs2-devel] [PATCH] ocfs2: fix __ocfs2_cluster_lock() dead lock In-Reply-To: <20100113075752.GA23372@mail.oracle.com> References: <201001060835.o067n0EO000623@rcsinet13.oracle.com> <20100107020005.GC20095@mail.oracle.com> <20100109180521.GA5148@laptop.oracle.com> <20100112015946.GE20285@mail.oracle.com> <20100113032049.GA4045@laptop.oracle.com> <20100113075752.GA23372@mail.oracle.com> Message-ID: <4B4E1BA8.3060408@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com Joel Becker wrote: > On Wed, Jan 13, 2010 at 11:20:49AM +0800, Wengang Wang wrote: >> before update_holders, the lock could be DCed(since no BUSY flag set by >> here). >> >> and even after update_holders, the lock could be DCed too. >> >> so that we get ocfs2_cluster_lock()(with holders increased) returned sucessfully >> but actually we don't hold the dlm lock. --thus more than one node is >> considering that they have the (EX) lock. > > You make a good point. I don't like the solution you propose, > though. Another flag that's almost the same? Eww! There's got to be a > better way. I don't see how we can resolve this without another flag. It could be a mirror image of the PENDING flag. PENDING takes care of the gap between BUSY set and calling dlm_lock(). This flag has to take care of the gap between BUSY clear and inc_holders. Am working on improving Wengang's patch. Mark is strangely silent.