From patchwork Thu Feb 14 18:38:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikos Tsironis X-Patchwork-Id: 10813485 X-Patchwork-Delegate: snitzer@redhat.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3D3D41390 for ; Thu, 14 Feb 2019 18:39:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 282132EDAB for ; Thu, 14 Feb 2019 18:39:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 152682EDC1; Thu, 14 Feb 2019 18:39:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 49F432EDAB for ; Thu, 14 Feb 2019 18:39:01 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A1572CAA70; Thu, 14 Feb 2019 18:38:59 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A21E710001BC; Thu, 14 Feb 2019 18:38:57 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 16E24181A00C; Thu, 14 Feb 2019 18:38:55 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id x1EIcrYH008447 for ; Thu, 14 Feb 2019 13:38:53 -0500 Received: by smtp.corp.redhat.com (Postfix) id AB43160F9B; Thu, 14 Feb 2019 18:38:53 +0000 (UTC) Delivered-To: dm-devel@redhat.com Received: from mx1.redhat.com (ext-mx10.extmail.prod.ext.phx2.redhat.com [10.5.110.39]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 83F5460BEC; Thu, 14 Feb 2019 18:38:53 +0000 (UTC) Received: from mx0.arrikto.com (mx0.arrikto.com [212.71.252.59]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5051658584; Thu, 14 Feb 2019 18:38:50 +0000 (UTC) Received: from troi.prod.arr (mail.arr [10.99.0.5]) by mx0.arrikto.com (Postfix) with ESMTP id 486A2182004; Thu, 14 Feb 2019 20:38:48 +0200 (EET) Received: from snf-864.vm.snf.arr (snf-864.vm.snf.arr [10.97.70.29]) by troi.prod.arr (Postfix) with ESMTPSA id F342F60; Thu, 14 Feb 2019 20:38:47 +0200 (EET) From: Nikos Tsironis To: agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com Date: Thu, 14 Feb 2019 20:38:47 +0200 Message-Id: <20190214183847.23743-1-ntsironis@arrikto.com> X-Greylist: Sender passed SPF test, ACL 242 matched, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 14 Feb 2019 18:38:51 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 14 Feb 2019 18:38:51 +0000 (UTC) for IP:'212.71.252.59' DOMAIN:'mx0.arrikto.com' HELO:'mx0.arrikto.com' FROM:'ntsironis@arrikto.com' RCPT:'' X-RedHat-Spam-Score: -0.001 (SPF_PASS) 212.71.252.59 mx0.arrikto.com 212.71.252.59 mx0.arrikto.com X-Scanned-By: MIMEDefang 2.78 on 10.5.110.39 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-loop: dm-devel@redhat.com Cc: ejt@redhat.com Subject: [dm-devel] [PATCH] dm thin: Fix bug wrt FUA request completion X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Thu, 14 Feb 2019 18:39:00 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP When provisioning a new data block for a virtual block, either because the block was previously unallocated or because we are breaking sharing, if the whole block of data is being overwritten the bio that triggered the provisioning is issued immediately, skipping copying or zeroing of the data block. When this bio completes the new mapping is inserted in to the pool's metadata by process_prepared_mapping(), where the bio completion is signaled to the upper layers. This completion is signaled without first committing the metadata. If the bio in question has the REQ_FUA flag set and the system crashes right after its completion and before the next metadata commit, then the write is lost despite the REQ_FUA flag requiring that I/O completion for this request is only signaled after the data has been committed to non-volatile storage. Fix this by deferring the completion of overwrite bios, with the REQ_FUA flag set, after the metadata has been committed. Signed-off-by: Nikos Tsironis --- drivers/md/dm-thin.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 49 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index ca8af21bf644..322b87745a6f 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -257,6 +257,7 @@ struct pool { spinlock_t lock; struct bio_list deferred_flush_bios; + struct bio_list deferred_flush_completions; struct list_head prepared_mappings; struct list_head prepared_discards; struct list_head prepared_discards_pt2; @@ -956,6 +957,39 @@ static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m) mempool_free(m, &m->tc->pool->mapping_pool); } +static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio) +{ + struct pool *pool = tc->pool; + unsigned long flags; + + /* + * If the bio has the REQ_FUA flag set we must commit the metadata + * before signaling its completion. + */ + if (!bio_triggers_commit(tc, bio)) { + bio_endio(bio); + return; + } + + /* + * Complete bio with an error if earlier I/O caused changes to the + * metadata that can't be committed, e.g, due to I/O errors on the + * metadata device. + */ + if (dm_thin_aborted_changes(tc->td)) { + bio_io_error(bio); + return; + } + + /* + * Batch together any bios that trigger commits and then issue a + * single commit for them in process_deferred_bios(). + */ + spin_lock_irqsave(&pool->lock, flags); + bio_list_add(&pool->deferred_flush_completions, bio); + spin_unlock_irqrestore(&pool->lock, flags); +} + static void process_prepared_mapping(struct dm_thin_new_mapping *m) { struct thin_c *tc = m->tc; @@ -988,7 +1022,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) */ if (bio) { inc_remap_and_issue_cell(tc, m->cell, m->data_block); - bio_endio(bio); + complete_overwrite_bio(tc, bio); } else { inc_all_io_entry(tc->pool, m->cell->holder); remap_and_issue(tc, m->cell->holder, m->data_block); @@ -2317,7 +2351,7 @@ static void process_deferred_bios(struct pool *pool) { unsigned long flags; struct bio *bio; - struct bio_list bios; + struct bio_list bios, bio_completions; struct thin_c *tc; tc = get_first_thin(pool); @@ -2328,26 +2362,36 @@ static void process_deferred_bios(struct pool *pool) } /* - * If there are any deferred flush bios, we must commit - * the metadata before issuing them. + * If there are any deferred flush bios, we must commit the metadata + * before issuing them or signaling their completion. */ bio_list_init(&bios); + bio_list_init(&bio_completions); + spin_lock_irqsave(&pool->lock, flags); bio_list_merge(&bios, &pool->deferred_flush_bios); bio_list_init(&pool->deferred_flush_bios); + + bio_list_merge(&bio_completions, &pool->deferred_flush_completions); + bio_list_init(&pool->deferred_flush_completions); spin_unlock_irqrestore(&pool->lock, flags); - if (bio_list_empty(&bios) && + if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) && !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool))) return; if (commit(pool)) { + bio_list_merge(&bios, &bio_completions); + while ((bio = bio_list_pop(&bios))) bio_io_error(bio); return; } pool->last_commit_jiffies = jiffies; + while ((bio = bio_list_pop(&bio_completions))) + bio_endio(bio); + while ((bio = bio_list_pop(&bios))) generic_make_request(bio); }