From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Thu, 18 Oct 2007 18:27:39 -0700 (PDT) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.11.20060308/8.12.10/SuSE Linux 0.7) with SMTP id l9J1RRgn004695 for ; Thu, 18 Oct 2007 18:27:29 -0700 Message-ID: <47180922.4040709@sgi.com> Date: Fri, 19 Oct 2007 11:32:18 +1000 From: Lachlan McIlroy Reply-To: lachlan@sgi.com MIME-Version: 1.0 Subject: Re: review: use correct buffer flags when reading superblock References: <470C8F5B.90705@sgi.com> <20071010093451.GA7655@infradead.org> <20071010112505.GH23367404@sgi.com> <20071018154649.GA16837@infradead.org> In-Reply-To: <20071018154649.GA16837@infradead.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Christoph Hellwig Cc: David Chinner , xfs-dev , xfs-oss Christoph Hellwig wrote: > On Wed, Oct 10, 2007 at 09:25:06PM +1000, David Chinner wrote: >>> Where are these set up in the first time? AFAICS the buffer only written >>> out by xfs_unmountfs_writesb, xfs_syncsub and xfs_trans_log_buf, and all >>> these should only ever happen after log recovery has finished. >> It can also be written by xfsbufd when it has been bdwrite() >> or as a result of log tail pushing. > > Hmm, true. > >> Because the superblock buffer is XBF_FS_MANAGED, it does not get >> torn down when it is clean and has no references, so the XBF_ASYNC >> flag never gets cleared unless the fs specifically clears it. If the >> superblock is then not recovered out of any further transactions >> during recovery after xfsbufd flushed it, the XBF_ASYNC flag remains >> set for the re-read that is issued in xlog_do_recover() and we >> hang..... > > Makes sense as an explanation. I still don't really like patch, maybe > we should always clear the ASYNC flag in the b_iodone callback? > That sounds like a good idea. Or get rid of the XBF_FS_MANAGED special case and get a new fresh buffer each time.