From nobody Tue Feb 10 15:01:32 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1520670831961873.9160636100231; Sat, 10 Mar 2018 00:33:51 -0800 (PST) Received: from localhost ([::1]:49665 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1euZwt-0006Zn-6L for importer@patchew.org; Sat, 10 Mar 2018 03:33:51 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53676) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1euZrM-0002R9-Rk for qemu-devel@nongnu.org; Sat, 10 Mar 2018 03:28:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1euZrK-0000D6-7R for qemu-devel@nongnu.org; Sat, 10 Mar 2018 03:28:08 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56136 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 1euZrF-00008a-1P; Sat, 10 Mar 2018 03:28:01 -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 8E0CB402277A; Sat, 10 Mar 2018 08:28:00 +0000 (UTC) Received: from probe.redhat.com (ovpn-123-36.rdu2.redhat.com [10.10.123.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id 28ADA1007279; Sat, 10 Mar 2018 08:28:00 +0000 (UTC) From: John Snow To: qemu-block@nongnu.org Date: Sat, 10 Mar 2018 03:27:40 -0500 Message-Id: <20180310082746.24198-16-jsnow@redhat.com> In-Reply-To: <20180310082746.24198-1-jsnow@redhat.com> References: <20180310082746.24198-1-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 [10.11.55.7]); Sat, 10 Mar 2018 08:28:00 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Sat, 10 Mar 2018 08:28:00 +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] [PATCH v5 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 PENDING state, added in a forthcoming commit. - Upon being finalized, either automatically or explicitly by the user, jobs prepare to complete. - If any job fails preparation, all jobs call .abort. - Otherwise, they succeed and call .commit. Signed-off-by: John Snow --- blockjob.c | 30 +++++++++++++++++++++++++++--- include/block/blockjob_int.h | 10 ++++++++++ 2 files changed, 37 insertions(+), 3 deletions(-) diff --git a/blockjob.c b/blockjob.c index 7e03824751..1395d8eed1 100644 --- a/blockjob.c +++ b/blockjob.c @@ -415,6 +415,14 @@ static void block_job_update_rc(BlockJob *job) } } =20 +static int block_job_prepare(BlockJob *job) +{ + if (job->ret =3D=3D 0 && job->driver->prepare) { + job->ret =3D job->driver->prepare(job); + } + return job->ret; +} + static void block_job_commit(BlockJob *job) { assert(!job->ret); @@ -438,7 +446,7 @@ static void block_job_clean(BlockJob *job) } } =20 -static void block_job_completed_single(BlockJob *job) +static int block_job_completed_single(BlockJob *job) { assert(job->completed); =20 @@ -472,6 +480,7 @@ static void block_job_completed_single(BlockJob *job) QLIST_REMOVE(job, txn_list); block_job_txn_unref(job->txn); block_job_conclude(job); + return 0; } =20 static void block_job_cancel_async(BlockJob *job) @@ -487,17 +496,22 @@ static void block_job_cancel_async(BlockJob *job) job->cancelled =3D true; } =20 -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; =20 QLIST_FOREACH_SAFE(job, &txn->jobs, txn_list, next) { ctx =3D blk_get_aio_context(job->blk); aio_context_acquire(ctx); - fn(job); + rc =3D fn(job); aio_context_release(ctx); + if (rc) { + break; + } } + return rc; } =20 static int block_job_finish_sync(BlockJob *job, @@ -580,6 +594,8 @@ static void block_job_completed_txn_success(BlockJob *j= ob) { BlockJobTxn *txn =3D job->txn; BlockJob *other_job; + int rc =3D 0; + /* * Successful completion, see if there are other running jobs in this * txn. @@ -590,6 +606,14 @@ static void block_job_completed_txn_success(BlockJob *= job) } assert(other_job->ret =3D=3D 0); } + + /* Jobs may require some prep-work to complete without failure */ + rc =3D 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); =20 + /** + * If the callback is not NULL, prepare will be invoked when all the j= obs + * belonging to the same transaction complete; or upon this job's comp= letion + * 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 --=20 2.14.3