From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:38988 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756048AbeDVPIm (ORCPT ); Sun, 22 Apr 2018 11:08:42 -0400 Subject: [PATCH 08/10] xfs: btree scrub should check minrecs From: "Darrick J. Wong" Date: Sun, 22 Apr 2018 08:08:23 -0700 Message-ID: <152440970335.30048.3140499875347648459.stgit@magnolia> In-Reply-To: <152440964593.30048.15577210457233332459.stgit@magnolia> References: <152440964593.30048.15577210457233332459.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: darrick.wong@oracle.com Cc: linux-xfs@vger.kernel.org, bfoster@redhat.com From: Darrick J. Wong Strengthen the btree block header checks to detect the number of records being less than the btree type's minimum record count. Certain blocks are allowed to violate this constraint -- specifically any btree block at the top of the tree can have fewer than minrecs records. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster --- fs/xfs/scrub/btree.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c index ea972da..2d29dce 100644 --- a/fs/xfs/scrub/btree.c +++ b/fs/xfs/scrub/btree.c @@ -455,6 +455,44 @@ xfs_scrub_btree_check_owner( } /* + * Check that this btree block has at least minrecs records or is one of the + * special blocks that don't require that. + */ +STATIC void +xfs_scrub_btree_check_minrecs( + struct xfs_scrub_btree *bs, + int level, + struct xfs_btree_block *block) +{ + unsigned int numrecs; + int ok_level; + + numrecs = be16_to_cpu(block->bb_numrecs); + + /* More records than minrecs means the block is ok. */ + if (numrecs >= bs->cur->bc_ops->get_minrecs(bs->cur, level)) + return; + + /* + * Certain btree blocks /can/ have fewer than minrecs records. Any + * level greater than or equal to the level of the highest dedicated + * btree block are allowed to violate this constraint. + * + * For a btree rooted in a block, the btree root can have fewer than + * minrecs records. If the btree is rooted in an inode and does not + * store records in the root, the direct children of the root and the + * root itself can have fewer than minrecs records. + */ + ok_level = bs->cur->bc_nlevels - 1; + if (bs->cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) + ok_level--; + if (level >= ok_level) + return; + + xfs_scrub_btree_set_corrupt(bs->sc, bs->cur, level); +} + +/* * Grab and scrub a btree block given a btree pointer. Returns block * and buffer pointers (if applicable) if they're ok to use. */ @@ -491,6 +529,8 @@ xfs_scrub_btree_get_block( if (*pbp) xfs_scrub_buffer_recheck(bs->sc, *pbp); + xfs_scrub_btree_check_minrecs(bs, level, *pblock); + /* * Check the block's owner; this function absorbs error codes * for us.