From patchwork Fri Feb 23 23:51:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Snow X-Patchwork-Id: 10240039 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AF44660390 for ; Sat, 24 Feb 2018 00:06:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A0C5229A93 for ; Sat, 24 Feb 2018 00:06:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9596F29A97; Sat, 24 Feb 2018 00:06:31 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2C1BF29A93 for ; Sat, 24 Feb 2018 00:06:31 +0000 (UTC) Received: from localhost ([::1]:47955 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1epNME-0001O1-BQ for patchwork-qemu-devel@patchwork.kernel.org; Fri, 23 Feb 2018 19:06:30 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55441) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1epN8Q-0005xq-P2 for qemu-devel@nongnu.org; Fri, 23 Feb 2018 18:52:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1epN8N-000625-CT for qemu-devel@nongnu.org; Fri, 23 Feb 2018 18:52:14 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:44374 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1epN8F-0005kz-Ks; Fri, 23 Feb 2018 18:52:03 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E8EE6EB710; Fri, 23 Feb 2018 23:51:54 +0000 (UTC) Received: from probe.bos.redhat.com (dhcp-17-231.bos.redhat.com [10.18.17.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id B8491104947E; Fri, 23 Feb 2018 23:51:54 +0000 (UTC) From: John Snow To: qemu-block@nongnu.org Date: Fri, 23 Feb 2018 18:51:36 -0500 Message-Id: <20180223235142.21501-16-jsnow@redhat.com> In-Reply-To: <20180223235142.21501-1-jsnow@redhat.com> References: <20180223235142.21501-1-jsnow@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 23 Feb 2018 23:51:54 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 23 Feb 2018 23:51:54 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jsnow@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [RFC v4 15/21] blockjobs: add prepare callback X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, John Snow , pkrempa@redhat.com, jtc@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Some jobs upon finalization may need to perform some work that can still fail. If these jobs are part of a transaction, it's important that these callbacks fail the entire transaction. We allow for a new callback in addition to commit/abort/clean that allows us the opportunity to have fairly late-breaking failures in the transactional process. The expected flow is: - All jobs in a transaction converge to the WAITING state (added in a forthcoming commit) - All jobs prepare to call either commit/abort - If any job fails, is canceled, or fails preparation, all jobs call their .abort callback. - All jobs enter the PENDING state, awaiting manual intervention (also added in a forthcoming commit) - block-job-finalize is issued by the user/management layer - All jobs call their commit callbacks. Signed-off-by: John Snow --- blockjob.c | 34 +++++++++++++++++++++++++++++++--- include/block/blockjob_int.h | 10 ++++++++++ 2 files changed, 41 insertions(+), 3 deletions(-) diff --git a/blockjob.c b/blockjob.c index 8f02c03880..1c010ec100 100644 --- a/blockjob.c +++ b/blockjob.c @@ -394,6 +394,18 @@ static void block_job_update_rc(BlockJob *job) } } +static int block_job_prepare(BlockJob *job) +{ + if (job->ret) { + goto out; + } + if (job->driver->prepare) { + job->ret = job->driver->prepare(job); + } + out: + return job->ret; +} + static void block_job_commit(BlockJob *job) { assert(!job->ret); @@ -417,7 +429,7 @@ static void block_job_clean(BlockJob *job) } } -static void block_job_completed_single(BlockJob *job) +static int block_job_completed_single(BlockJob *job) { assert(job->completed); @@ -452,6 +464,7 @@ static void block_job_completed_single(BlockJob *job) block_job_txn_unref(job->txn); block_job_event_concluded(job); block_job_unref(job); + return 0; } static void block_job_cancel_async(BlockJob *job) @@ -467,17 +480,22 @@ static void block_job_cancel_async(BlockJob *job) job->cancelled = true; } -static void block_job_txn_apply(BlockJobTxn *txn, void fn(BlockJob *)) +static int block_job_txn_apply(BlockJobTxn *txn, int fn(BlockJob *)) { AioContext *ctx; BlockJob *job, *next; + int rc; QLIST_FOREACH_SAFE(job, &txn->jobs, txn_list, next) { ctx = blk_get_aio_context(job->blk); aio_context_acquire(ctx); - fn(job); + rc = fn(job); aio_context_release(ctx); + if (rc) { + break; + } } + return rc; } static void block_job_do_dismiss(BlockJob *job) @@ -567,6 +585,8 @@ static void block_job_completed_txn_success(BlockJob *job) { BlockJobTxn *txn = job->txn; BlockJob *other_job; + int rc = 0; + /* * Successful completion, see if there are other running jobs in this * txn. @@ -576,6 +596,14 @@ static void block_job_completed_txn_success(BlockJob *job) return; } } + + /* Jobs may require some prep-work to complete without failure */ + rc = block_job_txn_apply(txn, block_job_prepare); + if (rc) { + block_job_completed_txn_abort(job); + return; + } + /* We are the last completed job, commit the transaction. */ block_job_txn_apply(txn, block_job_completed_single); } diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h index 259d49b32a..642adce68b 100644 --- a/include/block/blockjob_int.h +++ b/include/block/blockjob_int.h @@ -53,6 +53,16 @@ struct BlockJobDriver { */ void (*complete)(BlockJob *job, Error **errp); + /** + * If the callback is not NULL, prepare will be invoked when all the jobs + * belonging to the same transaction complete; or upon this job's completion + * if it is not in a transaction. + * + * This callback will not be invoked if the job has already failed. + * If it fails, abort and then clean will be called. + */ + int (*prepare)(BlockJob *job); + /** * If the callback is not NULL, it will be invoked when all the jobs * belonging to the same transaction complete; or upon this job's