From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92106C433F5 for ; Thu, 14 Oct 2021 23:05:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E2E661090 for ; Thu, 14 Oct 2021 23:05:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234012AbhJNXH4 (ORCPT ); Thu, 14 Oct 2021 19:07:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:43060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230503AbhJNXHz (ORCPT ); Thu, 14 Oct 2021 19:07:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A557F6108B; Thu, 14 Oct 2021 23:05:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634252749; bh=a59R0YLbeXjH5akMkUIvATUQeYElBx5L12gBl7zalG0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AjSZtFV7732Y2hR3cgOZJh1OrmW9MvVfKinAePkxKPOgTobH5hxM5IFv2zXiBmD03 6xdEmbuUSRrfGZRHwT2K2rVVdMtiZVxqllCnOI4U5I/IV2T3/CnXdUNOThTJfTWNB8 U6GLGEUiPjSSdb4BWgPf0SbTViobGcRNAfP8iAcVG9WDuO9zhGyzEsG5eLZlcq5lQU jNub7UpZuvXSxPMWrHo/xdCHXdWFMiLO/3QTFFLnVO08T9IxbV5RFgBJZqx1PoQLAC tvhP0IzaXmrxwb5zY/ctCXNmRAJoXjGdcrItrpmRkOWV/plJh1d2bob3Pm3CzP3SK6 yDhcSQCPZy/Uw== Date: Thu, 14 Oct 2021 16:05:49 -0700 From: "Darrick J. Wong" To: Dave Chinner Cc: linux-xfs@vger.kernel.org, chandan.babu@oracle.com, hch@lst.de Subject: Re: [PATCH 01/17] xfs: fix incorrect decoding in xchk_btree_cur_fsbno Message-ID: <20211014230549.GM24307@magnolia> References: <163424261462.756780.16294781570977242370.stgit@magnolia> <163424262046.756780.2366797746965376855.stgit@magnolia> <20211014224813.GN2361455@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211014224813.GN2361455@dread.disaster.area> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Oct 15, 2021 at 09:48:13AM +1100, Dave Chinner wrote: > On Thu, Oct 14, 2021 at 01:17:00PM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > During review of subsequent patches, Dave and I noticed that this > > function doesn't work quite right -- accessing cur->bc_ino depends on > > the ROOT_IN_INODE flag, not LONG_PTRS. Fix that and the parentheses > > isssue. While we're at it, remove the piece that accesses cur->bc_ag, > > because block 0 of an AG is never part of a btree. > > > > Signed-off-by: Darrick J. Wong > > --- > > fs/xfs/scrub/trace.c | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > > > diff --git a/fs/xfs/scrub/trace.c b/fs/xfs/scrub/trace.c > > index c0ef53fe6611..93c13763c15e 100644 > > --- a/fs/xfs/scrub/trace.c > > +++ b/fs/xfs/scrub/trace.c > > @@ -24,10 +24,11 @@ xchk_btree_cur_fsbno( > > if (level < cur->bc_nlevels && cur->bc_bufs[level]) > > return XFS_DADDR_TO_FSB(cur->bc_mp, > > xfs_buf_daddr(cur->bc_bufs[level])); > > - if (level == cur->bc_nlevels - 1 && cur->bc_flags & XFS_BTREE_LONG_PTRS) > > + > > + if (level == cur->bc_nlevels - 1 && > > + (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)) > > return XFS_INO_TO_FSB(cur->bc_mp, cur->bc_ino.ip->i_ino); > > Ok. > > > - if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS)) > > - return XFS_AGB_TO_FSB(cur->bc_mp, cur->bc_ag.pag->pag_agno, 0); > > + > > But doesn't this break the tracing code on short pointers as the > tracing code does: > > TP_fast_assign( > xfs_fsblock_t fsbno = xchk_btree_cur_fsbno(cur, level); > ... > __entry->agno = XFS_FSB_TO_AGNO(cur->bc_mp, fsbno); > > > i.e. the tracing will no longer give the correct agno for per-ag > cursors that don't have any buffers attached to them at the current > level? Hmmm. By that logic, maybe we should get rid of the (level == cur->bc_nlevels - 1) check entirely so that any cursor without a buffer attached at that level will always provide *some* kind of breadcrumb to the tracepoints? I almost did that instead, except for the consideration that if you're tracing the online fsck code, you should /probably/ have at least one of xchk_stop/xrep_attempt/xchk_done included in the filter list so you can be certain of what the kernel is checking. --D > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com