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 C6F257FF2 for ; Tue, 20 Aug 2013 18:19:12 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay3.corp.sgi.com (Postfix) with ESMTP id 3F341AC001 for ; Tue, 20 Aug 2013 16:19:09 -0700 (PDT) Received: from ipmail04.adl6.internode.on.net (ipmail04.adl6.internode.on.net [150.101.137.141]) by cuda.sgi.com with ESMTP id dBzYbAbIW2BjeBtn for ; Tue, 20 Aug 2013 16:19:07 -0700 (PDT) Date: Wed, 21 Aug 2013 09:19:03 +1000 From: Dave Chinner Subject: Re: [PATCH 51/50] xfs: add xfs sb v4 support for dirent filetype field Message-ID: <20130820231903.GN6023@dastard> References: <1376304611-22994-1-git-send-email-david@fromorbit.com> <20130819201940.516942026@sgi.com> <5212AA1D.3000809@sandeen.net> <52137D3D.8060205@sgi.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <52137D3D.8060205@sgi.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: Mark Tinguely Cc: Eric Sandeen , xfs@oss.sgi.com On Tue, Aug 20, 2013 at 09:29:17AM -0500, Mark Tinguely wrote: > On 08/19/13 18:28, Eric Sandeen wrote: > >On 8/19/13 3:19 PM, Mark Tinguely wrote: > > > > > > > >Thanks, Mark! > > > >Has you been able to test this at all? > > There is no test for this feature. Yes I did my version of testing. > First adding each type of inode type and verifying it. Then fsstress > testing using the same seed for sb v4+feature, v4 plain, v5+feature. > The resulting directory and checked with xfs_db. fsstress was chosen You would have had to have modified xfs_db to do this - can you send the patches out for review? > because how it manipulate directory items. But fsstress doesn't build large directories, so I don't think you've done anywhere near enough testing to say that you'd done anything more than smoke tested it. Indeed, in testing the dirent code on v5 superblocks, Michael Semon triggered a corner case failure in the v5 directory code that I haven't ever triggered in all my testin. Run this on a v5 filesystem: # seq 200000 | xargs touch And watch it fail when splitting a leaf in a node format directory. It's taken several months of testing to uncover this problem, and it is almost certain to be a bug that causes directory corruption. fsstress doesn't get anywhere near the per-directory file count necessary to exercise these sorts of directory operations. The moral of the story: the XFS directory code is *very hard to validate*. This is an clear demonstration of why I want to be extremely conservative in bringing this feature to v4 filesystems. The risk of there being an undiscovered corruption bug in the dtype code, or it exposes a pre-existing corruption bug in the directory code is still significant. > >I do still owe a promised xfstest - but for that, we'll need at least mkfs > >& xfs_repair support. > > > > Dave made changes so that xfs_repair will run (find the correct > directory items) but the feature verification and repairs has not > been done, so technically this is an incomplete feature. The patches I sent won't support a new v4 superblock feature bit, so you had had to write code to do that. Can you post your userspace patches at well? > >* XFS_IOC_FSGEOM support so that xfs_info can report the difference > >* xfs_repair needs to know that it's a valid feature on V4 > > okay, it will run xfs_repair to the same level as v5. AND ...As > pointed out, there is no xfs_repair support to verify/correct the > feature in v5 and therefore v4 - (again it is the same directory > code). As is, this feature is incomplete. That could keep the kernel > portion from moving forward. That's not what XFS_IOC_FSGEOM is for. Adding the feature bit to the XFS_IOC_FSGEOM ioctl is to allow us to find out if the user has enabled the feature via xfs_info.... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs