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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 ADA64C5DF60 for ; Fri, 8 Nov 2019 12:13:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81AF2206A3 for ; Fri, 8 Nov 2019 12:13:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573215195; bh=GQey7TwbKvULlRfhwuWfjNyOcIhpTbmyqmXpesqkp0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NkNacPa1ZABZLexKvBoDKGh33oLpLrATa2LJBl10/q/zU8kcsKH72fQHv1f18rMjh M7nGn9yImmHwIfHPqH70GdCuzI/pinHleXbb3fJtv+tOoqbLUf2Lky5hs2Lu3VZt3b Wr5v3UWwHTmjZQY8rnii4lLfMEk67VIOhVUqYeU8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390281AbfKHMNN (ORCPT ); Fri, 8 Nov 2019 07:13:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:51418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732654AbfKHLia (ORCPT ); Fri, 8 Nov 2019 06:38:30 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5BB2D222C2; Fri, 8 Nov 2019 11:38:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573213109; bh=GQey7TwbKvULlRfhwuWfjNyOcIhpTbmyqmXpesqkp0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=icFy+Ooiw+m5pwkghf1SSsyR2bS188Bi9H6RXkFEj3vYs7K7EaBVdq4j7KgwKwdW3 h9IUs3TLefUJDERSJVAHq8KsKld7A88p75fjffvf5NYkA/gtSutw/wFxtNIZ44BD6P wfx8hl927NXQyWM7q3D2mEwhwUN9/B1/0az0Lb9c= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bob Peterson , Sasha Levin , cluster-devel@redhat.com Subject: [PATCH AUTOSEL 4.19 032/205] gfs2: Don't set GFS2_RDF_UPTODATE when the lvb is updated Date: Fri, 8 Nov 2019 06:34:59 -0500 Message-Id: <20191108113752.12502-32-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191108113752.12502-1-sashal@kernel.org> References: <20191108113752.12502-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bob Peterson [ Upstream commit 4f36cb36c9d14340bb200d2ad9117b03ce992cfe ] The GFS2_RDF_UPTODATE flag in the rgrp is used to determine when a rgrp buffer is valid. It's cleared when the glock is invalidated, signifying that the buffer data is now invalid. But before this patch, function update_rgrp_lvb was setting the flag when it determined it had a valid lvb. But that's an invalid assumption: just because you have a valid lvb doesn't mean you have valid buffers. After all, another node may have made the lvb valid, and this node just fetched it from the glock via dlm. Consider this scenario: 1. The file system is mounted with RGRPLVB option. 2. In gfs2_inplace_reserve it locks the rgrp glock EX, but thanks to GL_SKIP, it skips the gfs2_rgrp_bh_get. 3. Since loops == 0 and the allocation target (ap->target) is bigger than the largest known chunk of blocks in the rgrp (rs->rs_rbm.rgd->rd_extfail_pt) it skips that rgrp and bypasses the call to gfs2_rgrp_bh_get there as well. 4. update_rgrp_lvb sees the lvb MAGIC number is valid, so bypasses gfs2_rgrp_bh_get, but it still sets sets GFS2_RDF_UPTODATE due to this invalid assumption. 5. The next time update_rgrp_lvb is called, it sees the bit is set and just returns 0, assuming both the lvb and rgrp are both uptodate. But since this is a smaller allocation, or space has been freed by another node, thus adjusting the lvb values, it decides to use the rgrp for allocations, with invalid rd_free due to the fact it was never updated. This patch changes update_rgrp_lvb so it doesn't set the UPTODATE flag anymore. That way, it has no choice but to fetch the latest values. Signed-off-by: Bob Peterson Signed-off-by: Sasha Levin --- fs/gfs2/rgrp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 449d0cb45a845..63e5387c84d26 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1227,7 +1227,7 @@ static int update_rgrp_lvb(struct gfs2_rgrpd *rgd) rl_flags = be32_to_cpu(rgd->rd_rgl->rl_flags); rl_flags &= ~GFS2_RDF_MASK; rgd->rd_flags &= GFS2_RDF_MASK; - rgd->rd_flags |= (rl_flags | GFS2_RDF_UPTODATE | GFS2_RDF_CHECK); + rgd->rd_flags |= (rl_flags | GFS2_RDF_CHECK); if (rgd->rd_rgl->rl_unlinked == 0) rgd->rd_flags &= ~GFS2_RDF_CHECK; rgd->rd_free = be32_to_cpu(rgd->rd_rgl->rl_free); -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Date: Fri, 8 Nov 2019 06:34:59 -0500 Subject: [Cluster-devel] [PATCH AUTOSEL 4.19 032/205] gfs2: Don't set GFS2_RDF_UPTODATE when the lvb is updated In-Reply-To: <20191108113752.12502-1-sashal@kernel.org> References: <20191108113752.12502-1-sashal@kernel.org> Message-ID: <20191108113752.12502-32-sashal@kernel.org> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Bob Peterson [ Upstream commit 4f36cb36c9d14340bb200d2ad9117b03ce992cfe ] The GFS2_RDF_UPTODATE flag in the rgrp is used to determine when a rgrp buffer is valid. It's cleared when the glock is invalidated, signifying that the buffer data is now invalid. But before this patch, function update_rgrp_lvb was setting the flag when it determined it had a valid lvb. But that's an invalid assumption: just because you have a valid lvb doesn't mean you have valid buffers. After all, another node may have made the lvb valid, and this node just fetched it from the glock via dlm. Consider this scenario: 1. The file system is mounted with RGRPLVB option. 2. In gfs2_inplace_reserve it locks the rgrp glock EX, but thanks to GL_SKIP, it skips the gfs2_rgrp_bh_get. 3. Since loops == 0 and the allocation target (ap->target) is bigger than the largest known chunk of blocks in the rgrp (rs->rs_rbm.rgd->rd_extfail_pt) it skips that rgrp and bypasses the call to gfs2_rgrp_bh_get there as well. 4. update_rgrp_lvb sees the lvb MAGIC number is valid, so bypasses gfs2_rgrp_bh_get, but it still sets sets GFS2_RDF_UPTODATE due to this invalid assumption. 5. The next time update_rgrp_lvb is called, it sees the bit is set and just returns 0, assuming both the lvb and rgrp are both uptodate. But since this is a smaller allocation, or space has been freed by another node, thus adjusting the lvb values, it decides to use the rgrp for allocations, with invalid rd_free due to the fact it was never updated. This patch changes update_rgrp_lvb so it doesn't set the UPTODATE flag anymore. That way, it has no choice but to fetch the latest values. Signed-off-by: Bob Peterson Signed-off-by: Sasha Levin --- fs/gfs2/rgrp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 449d0cb45a845..63e5387c84d26 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1227,7 +1227,7 @@ static int update_rgrp_lvb(struct gfs2_rgrpd *rgd) rl_flags = be32_to_cpu(rgd->rd_rgl->rl_flags); rl_flags &= ~GFS2_RDF_MASK; rgd->rd_flags &= GFS2_RDF_MASK; - rgd->rd_flags |= (rl_flags | GFS2_RDF_UPTODATE | GFS2_RDF_CHECK); + rgd->rd_flags |= (rl_flags | GFS2_RDF_CHECK); if (rgd->rd_rgl->rl_unlinked == 0) rgd->rd_flags &= ~GFS2_RDF_CHECK; rgd->rd_free = be32_to_cpu(rgd->rd_rgl->rl_free); -- 2.20.1