From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50788) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZDPHw-0008AU-De for qemu-devel@nongnu.org; Thu, 09 Jul 2015 23:47:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZDPHv-0007D3-3P for qemu-devel@nongnu.org; Thu, 09 Jul 2015 23:47:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40833) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZDPHu-0007Cp-S2 for qemu-devel@nongnu.org; Thu, 09 Jul 2015 23:47:47 -0400 From: Fam Zheng Date: Fri, 10 Jul 2015 11:46:47 +0800 Message-Id: <1436500012-32593-11-git-send-email-famz@redhat.com> In-Reply-To: <1436500012-32593-1-git-send-email-famz@redhat.com> References: <1436500012-32593-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v3 10/15] block: add block job transactions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , famz@redhat.com, John Snow , Jeff Cody , Max Reitz , vsementsov@parallels.com, stefanha@redhat.com From: Stefan Hajnoczi Sometimes block jobs must execute as a transaction group. Finishing jobs wait until all other jobs are ready to complete successfully. Failure or cancellation of one job cancels the other jobs in the group. Signed-off-by: Stefan Hajnoczi [Rewrite the implementation which is now contained in block_job_completed. --Fam] Signed-off-by: Fam Zheng --- blockjob.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++ include/block/block.h | 1 + include/block/blockjob.h | 26 +++++++++++++++ 3 files changed, 113 insertions(+) diff --git a/blockjob.c b/blockjob.c index e057dd5..7b59b53 100644 --- a/blockjob.c +++ b/blockjob.c @@ -36,6 +36,16 @@ #include "qemu/timer.h" #include "qapi-event.h" +/* Transactional group of block jobs */ +struct BlockJobTxn { + + /* Is this txn being cancelled? */ + bool aborting; + + /* List of jobs */ + QLIST_HEAD(, BlockJob) jobs; +}; + void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, int64_t speed, BlockCompletionFunc *cb, void *opaque, Error **errp) @@ -84,6 +94,59 @@ void block_job_release(BlockDriverState *bs) g_free(job); } +static void block_job_completed_txn(BlockJobTxn *txn, BlockJob *job, int ret) +{ + AioContext *ctx; + BlockJob *other_job, *next; + if (ret < 0 || block_job_is_cancelled(job)) { + if (!txn->aborting) { + /* We are the first failed job. Cancel other jobs. */ + txn->aborting = true; + QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) { + if (other_job == job || other_job->completed) { + continue; + } + ctx = bdrv_get_aio_context(other_job->bs); + aio_context_acquire(ctx); + block_job_cancel_sync(other_job); + assert(other_job->completed); + aio_context_release(ctx); + } + QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) { + if (other_job->driver->txn_abort) { + other_job->driver->txn_abort(other_job); + } + other_job->cb(other_job->opaque, + other_job->ret ? : -ECANCELED); + block_job_release(other_job->bs); + } + } else { + /* + * We are cancelled by another job, who will handle everything. + */ + return; + } + } else { + /* + * Successful completion, see if there is other running jobs in this + * txn. */ + QLIST_FOREACH(other_job, &txn->jobs, txn_list) { + if (!other_job->completed) { + return; + } + } + /* We are the last completed job, commit the transaction. */ + QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) { + if (other_job->driver->txn_commit) { + other_job->driver->txn_commit(other_job); + } + assert(other_job->ret == 0); + other_job->cb(other_job->opaque, 0); + block_job_release(other_job->bs); + } + } +} + void block_job_completed(BlockJob *job, int ret) { BlockDriverState *bs = job->bs; @@ -96,6 +159,10 @@ void block_job_completed(BlockJob *job, int ret) qemu_bh_delete(job->defer_to_main_loop_data.bh); job->defer_to_main_loop_data.bh = NULL; } + if (job->txn) { + block_job_completed_txn(job->txn, job, ret); + return; + } job->cb(job->opaque, ret); block_job_release(bs); } @@ -384,3 +451,22 @@ void block_job_defer_to_main_loop(BlockJob *job, qemu_bh_schedule(data->bh); } + +BlockJobTxn *block_job_txn_new(void) +{ + BlockJobTxn *txn = g_new0(BlockJobTxn, 1); + QLIST_INIT(&txn->jobs); + return txn; +} + +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job) +{ + if (!txn) { + return; + } + + assert(!job->txn); + job->txn = txn; + + QLIST_INSERT_HEAD(&txn->jobs, job, txn_list); +} diff --git a/include/block/block.h b/include/block/block.h index 7437590..c7fc5b6 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -13,6 +13,7 @@ typedef struct BlockDriver BlockDriver; typedef struct BlockJob BlockJob; typedef struct BdrvChildRole BdrvChildRole; +typedef struct BlockJobTxn BlockJobTxn; typedef struct BlockDriverInfo { /* in bytes, 0 if irrelevant */ diff --git a/include/block/blockjob.h b/include/block/blockjob.h index 5bac2e2..d854ee0 100644 --- a/include/block/blockjob.h +++ b/include/block/blockjob.h @@ -157,6 +157,9 @@ struct BlockJob { */ int ret; + /** Non-NULL if this job is part of a transaction */ + BlockJobTxn *txn; + QLIST_ENTRY(BlockJob) txn_list; }; /** @@ -389,4 +392,27 @@ void block_job_defer_to_main_loop(BlockJob *job, BlockJobDeferToMainLoopFn *fn, void *opaque); +/** + * block_job_txn_new: + * + * Allocate and return a new block job transaction. Jobs can be added to the + * transaction using block_job_txn_add_job(). + * + * All jobs in the transaction either complete successfully or fail/cancel as a + * group. Jobs wait for each other before completing. Cancelling one job + * cancels all jobs in the transaction. + */ +BlockJobTxn *block_job_txn_new(void); + +/** + * block_job_txn_add_job: + * @txn: The transaction (may be NULL) + * @job: Job to add to the transaction + * + * Add @job to the transaction. The @job must not already be in a transaction. + * The block job driver must call block_job_txn_prepare_to_complete() before + * final cleanup and completion. + */ +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job); + #endif -- 2.4.3