From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 6A1177F8C for ; Tue, 15 Jul 2014 19:39:29 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay2.corp.sgi.com (Postfix) with ESMTP id 4BED4304048 for ; Tue, 15 Jul 2014 17:39:29 -0700 (PDT) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by cuda.sgi.com with ESMTP id 4W6EFQNGa8qUWLv2 for ; Tue, 15 Jul 2014 17:39:27 -0700 (PDT) Date: Wed, 16 Jul 2014 10:38:51 +1000 From: Dave Chinner Subject: Re: [PATCH] logprint: Fix printing of AGF buffers Message-ID: <20140716003851.GO22339@dastard> References: <1405349100-19734-1-git-send-email-jack@suse.cz> <20140715101931.GC30363@infradead.org> <20140715140938.GA1733@quack.suse.cz> <20140715153922.GB5369@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140715153922.GB5369@infradead.org> 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: Christoph Hellwig Cc: Jan Kara , xfs@oss.sgi.com On Tue, Jul 15, 2014 at 08:39:22AM -0700, Christoph Hellwig wrote: > On Tue, Jul 15, 2014 at 04:09:38PM +0200, Jan Kara wrote: > > I had a look before I submitted this patch and I didn't find anything. > > Now that I'm looking again, AGI buffers probably need a similar treatment. > > Superblock buffers are already checked against fixed number so those don't > > have a problem. Dquot buffers should be fine as well because those don't > > have a checksum and other unlogged stuff. And I didn't find any other > > structures in the log that would have the problem (please point me if I > > missed something). > > > > Regarding how to fix this cleanly - offsetof() seems like a reasonably > > clean way to me. If you prefer to define number of bytes each buffer type > > has to have in the log, I can do that as well. Or I could define > > alternative structures only containing fields we need in the log so that we > > can print info but this all seems like an additional complexity with > > disputable gain... > > I've taken a bit of a closer log (OMG, what a mess logprint is..), and > it seems at least in this are the AGF and AGI are affected of the struct > growth in v4. Yes, logprint is a steaming pile. At some point I'll properly abstract the kernel side log recovery code and share that with userspace and then convert logprint to use that.... > It seems like in this specific case using your offsetoff trick is > fine, it just needs a good comment explaining it. I added this: /* * The addition of spare space and the non-logged CRC format * fields to the AGF mean that the size that is logged is almost * always going to be smaller than the structure itself. Hence * we need to make sure that the buffer contains all the data we * want to print rather than just check against the structure * size. */ Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs