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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 D6917C169C4 for ; Tue, 29 Jan 2019 12:08:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A803420882 for ; Tue, 29 Jan 2019 12:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548763680; bh=eHWD7ygfITcMbq+U6KkoekqpgaLEIGD8etCzc3215ls=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZAbbMZRQK2gSQ5NpbNMMOQXCiQRpsC9HUS77fVbvd9IWTkhhK+4IhoNmtFVjgSRVY 9rg3CF5x0qxmD5o+KOyEAcvitbZqZplbud6NZXUt2zuHQi/FWOfdLc7bHlGGJC8+BY lx/nIkDhL/1DsBaC54HVkfelSVQK7Gal1CQrkmZY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728628AbfA2MHx (ORCPT ); Tue, 29 Jan 2019 07:07:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:56710 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729515AbfA2Ljw (ORCPT ); Tue, 29 Jan 2019 06:39:52 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E3D8D2148E; Tue, 29 Jan 2019 11:39:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548761991; bh=eHWD7ygfITcMbq+U6KkoekqpgaLEIGD8etCzc3215ls=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hB87o/f9ITVmOFiEHfr9LAnI9UVeRrFALQojbdGcXHxsJEfB9b0xjDUYZak81m5w6 qX6KBzy0xLuVadet/cUHj49HlMkLGuiwa+iclOG35uCOmOe/N0/x6a5V/HJEez4Ss1 aKXRTmmjKCbUURMY894nXj6cVUr+AX0cLGLHTpro= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, ryan.p.norwood@gmail.com, Joe Thornber , Mike Snitzer Subject: [PATCH 4.20 072/117] dm thin: fix passdown_double_checking_shared_status() Date: Tue, 29 Jan 2019 12:35:23 +0100 Message-Id: <20190129113211.130270218@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190129113207.477505932@linuxfoundation.org> References: <20190129113207.477505932@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joe Thornber commit d445bd9cec1a850c2100fcf53684c13b3fd934f2 upstream. Commit 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") changed process_prepared_discard_passdown_pt1() to increment all the blocks being discarded until after the passdown had completed to avoid them being prematurely reused. IO issued to a thin device that breaks sharing with a snapshot, followed by a discard issued to snapshot(s) that previously shared the block(s), results in passdown_double_checking_shared_status() being called to iterate through the blocks double checking their reference count is zero and issuing the passdown if so. So a side effect of commit 00a0ea33b495 is passdown_double_checking_shared_status() was broken. Fix this by checking if the block reference count is greater than 1. Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared(). Fixes: 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") Cc: stable@vger.kernel.org # 4.9+ Reported-by: ryan.p.norwood@gmail.com Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-thin-metadata.c | 4 ++-- drivers/md/dm-thin-metadata.h | 2 +- drivers/md/dm-thin.c | 10 +++++----- 3 files changed, 8 insertions(+), 8 deletions(-) --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1678,7 +1678,7 @@ int dm_thin_remove_range(struct dm_thin_ return r; } -int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result) +int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result) { int r; uint32_t ref_count; @@ -1686,7 +1686,7 @@ int dm_pool_block_is_used(struct dm_pool down_read(&pmd->root_lock); r = dm_sm_get_count(pmd->data_sm, b, &ref_count); if (!r) - *result = (ref_count != 0); + *result = (ref_count > 1); up_read(&pmd->root_lock); return r; --- a/drivers/md/dm-thin-metadata.h +++ b/drivers/md/dm-thin-metadata.h @@ -195,7 +195,7 @@ int dm_pool_get_metadata_dev_size(struct int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result); -int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result); +int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result); int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e); int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e); --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -1048,7 +1048,7 @@ static void passdown_double_checking_sha * passdown we have to check that these blocks are now unused. */ int r = 0; - bool used = true; + bool shared = true; struct thin_c *tc = m->tc; struct pool *pool = tc->pool; dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin; @@ -1058,11 +1058,11 @@ static void passdown_double_checking_sha while (b != end) { /* find start of unmapped run */ for (; b < end; b++) { - r = dm_pool_block_is_used(pool->pmd, b, &used); + r = dm_pool_block_is_shared(pool->pmd, b, &shared); if (r) goto out; - if (!used) + if (!shared) break; } @@ -1071,11 +1071,11 @@ static void passdown_double_checking_sha /* find end of run */ for (e = b + 1; e != end; e++) { - r = dm_pool_block_is_used(pool->pmd, e, &used); + r = dm_pool_block_is_shared(pool->pmd, e, &shared); if (r) goto out; - if (used) + if (shared) break; }