From: Fam Zheng <famz@redhat.com>
To: qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
famz@redhat.com, John Snow <jsnow@redhat.com>,
Jeff Cody <jcody@redhat.com>, Max Reitz <mreitz@redhat.com>,
vsementsov@parallels.com, stefanha@redhat.com
Subject: [Qemu-devel] [PATCH v3 10/15] block: add block job transactions
Date: Fri, 10 Jul 2015 11:46:47 +0800 [thread overview]
Message-ID: <1436500012-32593-11-git-send-email-famz@redhat.com> (raw)
In-Reply-To: <1436500012-32593-1-git-send-email-famz@redhat.com>
From: Stefan Hajnoczi <stefanha@redhat.com>
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 <stefanha@redhat.com>
[Rewrite the implementation which is now contained in block_job_completed.
--Fam]
Signed-off-by: Fam Zheng <famz@redhat.com>
---
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
next prev parent reply other threads:[~2015-07-10 3:47 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-10 3:46 [Qemu-devel] [PATCH v3 00/15] block: incremental backup transactions using BlockJobTxn Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 01/15] qapi: Add transaction support to block-dirty-bitmap operations Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 02/15] iotests: add transactional incremental backup test Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 03/15] block: rename BlkTransactionState and BdrvActionOps Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 04/15] block: keep bitmap if incremental backup job is cancelled Fam Zheng
2015-07-13 19:48 ` John Snow
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 05/15] backup: Extract dirty bitmap handling as a separate function Fam Zheng
2015-07-13 23:06 ` John Snow
2015-07-14 2:46 ` Fam Zheng
2015-07-14 8:26 ` Stefan Hajnoczi
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 06/15] blockjob: Add .txn_commit and .txn_abort transaction actions Fam Zheng
2015-07-13 23:06 ` John Snow
2015-07-14 8:35 ` Stefan Hajnoczi
2015-07-14 9:26 ` Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 07/15] blockjob: Add "completed" and "ret" in BlockJob Fam Zheng
2015-07-13 23:08 ` John Snow
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 08/15] blockjob: Simplify block_job_finish_sync Fam Zheng
2015-07-13 23:08 ` John Snow
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 09/15] blockjob: Move BlockJobDeferToMainLoopData into BlockJob Fam Zheng
2015-07-14 10:03 ` Stefan Hajnoczi
2015-07-14 10:36 ` Fam Zheng
2015-07-10 3:46 ` Fam Zheng [this message]
2015-07-13 23:12 ` [Qemu-devel] [PATCH v3 10/15] block: add block job transactions John Snow
2015-07-14 3:04 ` Fam Zheng
2015-07-14 15:05 ` John Snow
2015-07-14 10:27 ` Stefan Hajnoczi
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 11/15] blockdev: make BlockJobTxn available to qmp 'transaction' Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 12/15] block/backup: support block job transactions Fam Zheng
2015-07-13 23:14 ` John Snow
2015-07-14 3:12 ` Fam Zheng
2015-07-14 10:32 ` Stefan Hajnoczi
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 13/15] iotests: 124 - transactional failure test Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 14/15] qmp-commands.hx: Update the supported 'transaction' operations Fam Zheng
2015-07-10 3:46 ` [Qemu-devel] [PATCH v3 15/15] tests: add BlockJobTxn unit test Fam Zheng
2015-07-13 23:14 ` John Snow
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