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 X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9169C433ED for ; Tue, 6 Apr 2021 13:57:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80ACB61279 for ; Tue, 6 Apr 2021 13:57:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244287AbhDFN5h (ORCPT ); Tue, 6 Apr 2021 09:57:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:37206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235074AbhDFN5e (ORCPT ); Tue, 6 Apr 2021 09:57:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2357B61260; Tue, 6 Apr 2021 13:57:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617717446; bh=jusJBIDBkMrA+UiQrH5Z/m+hJXbLJqQAdhkS4cyBpek=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Gcs2zrrO9G9fGOnaBswNr0K7DplIUHiti8KtL621M15INxJ6oRdkZ9jwbGOiE7VYV n0zzhBZwRvHZoP2YQLShdNCeR2f/s3YUlQHEfgYfkSDpOVK0Z8QbmP+Oi1PfDCPeU+ 8L62ctDmz8BNSfkE3qHIRSg7kPAqADbuOQJIfBUG/ewkg4RHMv6hCUyVP/bU3V8baI PqcCiW7vtRbpFFPCUu3BSvXpa2jnh4U4BG5eUIjl0VRtiIAqQpwTtgRH7aV3NqU0yt 0HauBW7KHg87kqSZc+/P+LiuNurv7lOx3OTMBDSkE9OM25jH0IEO0VQ+rQ1qBbVksZ +N7nnHyMGsnvg== Date: Tue, 6 Apr 2021 06:57:26 -0700 From: "Darrick J. Wong" To: Chandan Babu R Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH V2] xfs: scrub: Disable check for unoptimized data fork bmbt node Message-ID: <20210406135726.GF3957620@magnolia> References: <20210406065519.696-1-chandanrlinux@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210406065519.696-1-chandanrlinux@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Apr 06, 2021 at 12:25:19PM +0530, Chandan Babu R wrote: > xchk_btree_check_minrecs() checks if the contents of the immediate child of a > bmbt root block can fit within the root block. This check could fail on inodes > with an attr fork since xfs_bmap_add_attrfork_btree() used to demote the > current root node of the data fork as the child of a newly allocated root node > if it found that the size of "struct xfs_btree_block" along with the space > required for records exceeded that of space available in the data fork. > > xfs_bmap_add_attrfork_btree() should have used "struct xfs_bmdr_block" instead > of "struct xfs_btree_block" for the above mentioned space requirement > calculation. This commit disables the check for unoptimized (in terms of > disk space usage) data fork bmbt trees since there could be filesystems > in use that already have such a layout. > > Suggested-by: Darrick J. Wong > Signed-off-by: Chandan Babu R Looks good! Reviewed-by: Darrick J. Wong --D > --- > Changelog: > V1 -> V2: > 1. Apply "minimum records check" restriction only to BMBT btrees. > > fs/xfs/scrub/btree.c | 30 ++++++++++++++++++++++++++++-- > 1 file changed, 28 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c > index debf392e0515..a94bd8122c60 100644 > --- a/fs/xfs/scrub/btree.c > +++ b/fs/xfs/scrub/btree.c > @@ -9,6 +9,7 @@ > #include "xfs_format.h" > #include "xfs_trans_resv.h" > #include "xfs_mount.h" > +#include "xfs_inode.h" > #include "xfs_btree.h" > #include "scrub/scrub.h" > #include "scrub/common.h" > @@ -442,6 +443,30 @@ xchk_btree_check_owner( > return xchk_btree_check_block_owner(bs, level, XFS_BUF_ADDR(bp)); > } > > +/* Decide if we want to check minrecs of a btree block in the inode root. */ > +static inline bool > +xchk_btree_check_iroot_minrecs( > + struct xchk_btree *bs) > +{ > + /* > + * xfs_bmap_add_attrfork_btree had an implementation bug wherein it > + * would miscalculate the space required for the data fork bmbt root > + * when adding an attr fork, and promote the iroot contents to an > + * external block unnecessarily. This went unnoticed for many years > + * until scrub found filesystems in this state. Inode rooted btrees are > + * not supposed to have immediate child blocks that are small enough > + * that the contents could fit in the inode root, but we can't fail > + * existing filesystems, so instead we disable the check for data fork > + * bmap btrees when there's an attr fork. > + */ > + if (bs->cur->bc_btnum == XFS_BTNUM_BMAP && > + bs->cur->bc_ino.whichfork == XFS_DATA_FORK && > + XFS_IFORK_Q(bs->sc->ip)) > + return false; > + > + return true; > +} > + > /* > * Check that this btree block has at least minrecs records or is one of the > * special blocks that don't require that. > @@ -475,8 +500,9 @@ xchk_btree_check_minrecs( > > root_block = xfs_btree_get_block(cur, root_level, &root_bp); > root_maxrecs = cur->bc_ops->get_dmaxrecs(cur, root_level); > - if (be16_to_cpu(root_block->bb_numrecs) != 1 || > - numrecs <= root_maxrecs) > + if (xchk_btree_check_iroot_minrecs(bs) && > + (be16_to_cpu(root_block->bb_numrecs) != 1 || > + numrecs <= root_maxrecs)) > xchk_btree_set_corrupt(bs->sc, cur, level); > return; > } > -- > 2.29.2 >