From patchwork Tue Oct 13 16:58:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 11835785 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 94C40A5C8 for ; Tue, 13 Oct 2020 18:11:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6150F2530A for ; Tue, 13 Oct 2020 17:01:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="M1RHRWhd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726780AbgJMRA7 (ORCPT ); Tue, 13 Oct 2020 13:00:59 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:42842 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726772AbgJMRA7 (ORCPT ); Tue, 13 Oct 2020 13:00:59 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09DGwesu138000; Tue, 13 Oct 2020 17:00:56 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type; s=corp-2020-01-29; bh=AEULCGoazW6p+wXUshZ4QF5+dVJIwsMPJOoGdDsckGE=; b=M1RHRWhd8KCsaRLncOy60eQSKq+p+cPIAjVY07h1ykeKOKzZ2vGlEjYNFYcyAGY7q+yO J3LwqPLpJkqpxiS7UO/f0YxcLaxdEEMd9RP80YdBm8u766laE06K700M3p2GPfazP0AT 7nju6qpWg70/0EPIfrNlEfwwOlM1M6YNW9HqZE6xm9oOA+JRrKT+1dW9k85dLeewjI7g rGShYRtgn+4k2DzBe0mcqEoBkzrEOYJRy0W8zpOPUq9lfCJsAoS8PMSODWTIKBlEYAxG hcZtnQQXoZaoQlYth6iF6Fej3N/qYTjEcnzr5nPIrizvH6FDL/GWrBf1QkpRUhDLpnwb aA== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2130.oracle.com with ESMTP id 343pajsxs2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 13 Oct 2020 17:00:56 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09DGnkgk188627; Tue, 13 Oct 2020 16:58:55 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 344by2fste-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 13 Oct 2020 16:58:55 +0000 Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09DGwsBQ018971; Tue, 13 Oct 2020 16:58:55 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 13 Oct 2020 09:58:54 -0700 Date: Tue, 13 Oct 2020 09:58:53 -0700 From: "Darrick J. Wong" To: xfs Cc: Chandan Babu R , Allison Collins , "Bill O'Donnell" Subject: [PATCH] xfs: fix high key handling in the rt allocator's query_range function Message-ID: <20201013165853.GC9832@magnolia> MIME-Version: 1.0 Content-Disposition: inline X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9773 signatures=668681 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 spamscore=0 suspectscore=5 mlxscore=0 malwarescore=0 adultscore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010130123 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9773 signatures=668681 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 suspectscore=5 impostorscore=0 priorityscore=1501 clxscore=1015 malwarescore=0 adultscore=0 lowpriorityscore=0 spamscore=0 phishscore=0 mlxscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010130124 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Darrick J. Wong Fix some off-by-one errors in xfs_rtalloc_query_range. The highest key in the realtime bitmap is always one less than the number of rt extents, which means that the key clamp at the start of the function is wrong. The 4th argument to xfs_rtfind_forw is the highest rt extent that we want to probe, which means that passing 1 less than the high key is wrong. Finally, drop the rem variable that controls the loop because we can compare the iteration point (rtstart) against the high key directly. The sordid history of this function is that the original commit (fb3c3) incorrectly passed (high_rec->ar_startblock - 1) as the 'limit' parameter to xfs_rtfind_forw. This was wrong because the "high key" is supposed to be the largest key for which the caller wants result rows, not the key for the first row that could possibly be outside the range that the caller wants to see. A subsequent attempt (8ad56) to strengthen the parameter checking added incorrect clamping of the parameters to the number of rt blocks in the system (despite the bitmap functions all taking units of rt extents) to avoid querying ranges past the end of rt bitmap file but failed to fix the incorrect _rtfind_forw parameter. The original _rtfind_forw parameter error then survived the conversion of the startblock and blockcount fields to rt extents (a0e5c), and the most recent off-by-one fix (a3a37) thought it was patching a problem when the end of the rt volume is not in use, but none of these fixes actually solved the original problem that the author was confused about the "limit" argument to xfs_rtfind_forw. Sadly, all four of these patches were written by this author and even his own usage of this function and rt testing were inadequate to get this fixed quickly. Original-problem: fb3c3de2f65c ("xfs: add a couple of queries to iterate free extents in the rtbitmap") Not-fixed-by: 8ad560d2565e ("xfs: strengthen rtalloc query range checks") Not-fixed-by: a0e5c435babd ("xfs: fix xfs_rtalloc_rec units") Fixes: a3a374bf1889 ("xfs: fix off-by-one error in xfs_rtalloc_query_range") Signed-off-by: Darrick J. Wong Reviewed-by: Chandan Babu R --- fs/xfs/libxfs/xfs_rtbitmap.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c index 1d9fa8a300f1..6c1aba16113c 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.c +++ b/fs/xfs/libxfs/xfs_rtbitmap.c @@ -1018,7 +1018,6 @@ xfs_rtalloc_query_range( struct xfs_mount *mp = tp->t_mountp; xfs_rtblock_t rtstart; xfs_rtblock_t rtend; - xfs_rtblock_t rem; int is_free; int error = 0; @@ -1027,13 +1026,12 @@ xfs_rtalloc_query_range( if (low_rec->ar_startext >= mp->m_sb.sb_rextents || low_rec->ar_startext == high_rec->ar_startext) return 0; - if (high_rec->ar_startext > mp->m_sb.sb_rextents) - high_rec->ar_startext = mp->m_sb.sb_rextents; + high_rec->ar_startext = min(high_rec->ar_startext, + mp->m_sb.sb_rextents - 1); /* Iterate the bitmap, looking for discrepancies. */ rtstart = low_rec->ar_startext; - rem = high_rec->ar_startext - rtstart; - while (rem) { + while (rtstart <= high_rec->ar_startext) { /* Is the first block free? */ error = xfs_rtcheck_range(mp, tp, rtstart, 1, 1, &rtend, &is_free); @@ -1042,7 +1040,7 @@ xfs_rtalloc_query_range( /* How long does the extent go for? */ error = xfs_rtfind_forw(mp, tp, rtstart, - high_rec->ar_startext - 1, &rtend); + high_rec->ar_startext, &rtend); if (error) break; @@ -1055,7 +1053,6 @@ xfs_rtalloc_query_range( break; } - rem -= rtend - rtstart + 1; rtstart = rtend + 1; }