From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2120.oracle.com ([156.151.31.85]:58524 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726918AbeLEQsR (ORCPT ); Wed, 5 Dec 2018 11:48:17 -0500 Date: Wed, 5 Dec 2018 08:48:04 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH v2 2/6] xfs_repair: don't error out on dirs with a single leafn block Message-ID: <20181205164804.GK24487@magnolia> References: <154181071499.3727.3910572718199592407.stgit@magnolia> <154181072709.3727.17020900125846885320.stgit@magnolia> <20181122181346.GW6792@magnolia> <4580e90a-0040-6eb2-f499-7a45a6fe136c@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4580e90a-0040-6eb2-f499-7a45a6fe136c@sandeen.net> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Eric Sandeen Cc: Dave Chinner , linux-xfs@vger.kernel.org On Tue, Dec 04, 2018 at 10:11:50PM -0600, Eric Sandeen wrote: > > > On 12/4/18 9:48 PM, Eric Sandeen wrote: > > On 11/22/18 12:13 PM, Darrick J. Wong wrote: > >> From: Darrick J. Wong > >> > >> In process_node_dir2, we need to distinguish between a directory with a > >> single leafn block (yes, they exist) having no interior da nodes, and a > >> directory with a da tree that incorrectly points to dablk 0. If we > >> happened to fill out any part of the da cursor then we have a da btree > >> with garbage in it; otherwise, we have a single leafn block. > >> > >> This was found by repair repeatedly rebuilding a directory containing a > >> single leafn block (xfs/495). > >> > >> Fixes: 67a79e2cc932 ("xfs_repair: treat zero da btree pointers as corruption") > >> Reported-by: Dave Chinner > >> Signed-off-by: Darrick J. Wong > > > > I'm finding the commit log hard to parse/understand. > > > > Let's reference > > > > 71a6af8 Revert "xfs_repair: treat zero da btree pointers as corruption" > > > > for starters, but can we do something like this....? > > > > === > > > > As explained in > > > > 71a6af8 Revert "xfs_repair: treat zero da btree pointers as corruption" > > > > a single root LEAFN block can exist in a directory until it grows further. > > > > This is why, normally, we skip directories with a root marked > > XFS_DIR2_LEAFN_MAGIC, as detected by the left-most leaf block being > > found at file block 0. > > > > However, if we traversed any level of a btree to get here (as > > indicated by da_cursor.active > 0), then a leaf block claiming block > > 0 indicates corruption, and we should handle it as such, and rebuild > > the directory. > > > > This was found by repair repeatedly rebuilding a directory containing a > > single leafn block (xfs/495). > > > > Fixes: 67a79e2cc932 ("xfs_repair: treat zero da btree pointers as corruption") > > Reported-by: Dave Chinner > > Signed-off-by: Darrick J. Wong > > > > === > > > > I'm not hung up on rewriting the commit log, but if you like it give me > > thumbs up. I needed to think it through that way to grok the change. > > Anyway, for the change now that I do grok it, > > > > Reviewed-by: Eric Sandeen > > Uh, the summary is wrong too, o? We /already/ "don't error out" > on dirs with a single leafn block. Maybe: > > xfs_repair: rebuild directory when non-root leafn blocks claim block 0 > > ? Works for me. Want a resend or are you fixing it up on the way in? --D