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authorJohn Snow <jsnow@redhat.com>2018-03-10 03:27:43 -0500
committerKevin Wolf <kwolf@redhat.com>2018-03-19 12:01:24 +0100
commit11b61fbc0d1a447849f36d76e0e1d05be2dfaad2 (patch)
tree93bb4e5cc3452c6bc62021b982506b2f0187d133
parent5f241594c40875af526a53c7a8c6466e487f4e5e (diff)
downloadqemu-11b61fbc0d1a447849f36d76e0e1d05be2dfaad2.tar.gz
blockjobs: add block-job-finalize
Instead of automatically transitioning from PENDING to CONCLUDED, gate the .prepare() and .commit() phases behind an explicit acknowledgement provided by the QMP monitor if auto_finalize = false has been requested. This allows us to perform graph changes in prepare and/or commit so that graph changes do not occur autonomously without knowledge of the controlling management layer. Transactions that have reached the "PENDING" state together can all be moved to invoke their finalization methods by issuing block_job_finalize to any one job in the transaction. Jobs in a transaction with mixed job->auto_finalize settings will all remain stuck in the "PENDING" state, as if the entire transaction was specified with auto_finalize = false. Jobs that specified auto_finalize = true, however, will still not emit the PENDING event. Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/trace-events1
-rw-r--r--blockdev.c14
-rw-r--r--blockjob.c60
-rw-r--r--include/block/blockjob.h17
-rw-r--r--qapi/block-core.json23
5 files changed, 98 insertions, 17 deletions
diff --git a/block/trace-events b/block/trace-events
index 1c6edb0b5a..f8c50b4063 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -53,6 +53,7 @@ qmp_block_job_cancel(void *job) "job %p"
qmp_block_job_pause(void *job) "job %p"
qmp_block_job_resume(void *job) "job %p"
qmp_block_job_complete(void *job) "job %p"
+qmp_block_job_finalize(void *job) "job %p"
qmp_block_job_dismiss(void *job) "job %p"
qmp_block_stream(void *bs, void *job) "bs %p job %p"
diff --git a/blockdev.c b/blockdev.c
index fc35d7c7bb..96bbac6c53 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3872,6 +3872,20 @@ void qmp_block_job_complete(const char *device, Error **errp)
aio_context_release(aio_context);
}
+void qmp_block_job_finalize(const char *id, Error **errp)
+{
+ AioContext *aio_context;
+ BlockJob *job = find_block_job(id, &aio_context, errp);
+
+ if (!job) {
+ return;
+ }
+
+ trace_qmp_block_job_finalize(job);
+ block_job_finalize(job, errp);
+ aio_context_release(aio_context);
+}
+
void qmp_block_job_dismiss(const char *id, Error **errp)
{
AioContext *aio_context;
diff --git a/blockjob.c b/blockjob.c
index 0a22b924fe..d6b8bea514 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -65,6 +65,7 @@ bool BlockJobVerbTable[BLOCK_JOB_VERB__MAX][BLOCK_JOB_STATUS__MAX] = {
[BLOCK_JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
[BLOCK_JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
[BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
+ [BLOCK_JOB_VERB_FINALIZE] = {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
[BLOCK_JOB_VERB_DISMISS] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
};
@@ -449,7 +450,7 @@ static void block_job_clean(BlockJob *job)
}
}
-static int block_job_completed_single(BlockJob *job)
+static int block_job_finalize_single(BlockJob *job)
{
assert(job->completed);
@@ -590,18 +591,36 @@ static void block_job_completed_txn_abort(BlockJob *job)
assert(other_job->cancelled);
block_job_finish_sync(other_job, NULL, NULL);
}
- block_job_completed_single(other_job);
+ block_job_finalize_single(other_job);
aio_context_release(ctx);
}
block_job_txn_unref(txn);
}
+static int block_job_needs_finalize(BlockJob *job)
+{
+ return !job->auto_finalize;
+}
+
+static void block_job_do_finalize(BlockJob *job)
+{
+ int rc;
+ assert(job && job->txn);
+
+ /* prepare the transaction to complete */
+ rc = block_job_txn_apply(job->txn, block_job_prepare, true);
+ if (rc) {
+ block_job_completed_txn_abort(job);
+ } else {
+ block_job_txn_apply(job->txn, block_job_finalize_single, true);
+ }
+}
+
static void block_job_completed_txn_success(BlockJob *job)
{
BlockJobTxn *txn = job->txn;
BlockJob *other_job;
- int rc = 0;
block_job_state_transition(job, BLOCK_JOB_STATUS_WAITING);
@@ -616,16 +635,12 @@ static void block_job_completed_txn_success(BlockJob *job)
assert(other_job->ret == 0);
}
- /* Jobs may require some prep-work to complete without failure */
- rc = block_job_txn_apply(txn, block_job_prepare, true);
- 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_event_pending, false);
- block_job_txn_apply(txn, block_job_completed_single, true);
+
+ /* If no jobs need manual finalization, automatically do so */
+ if (block_job_txn_apply(txn, block_job_needs_finalize, false) == 0) {
+ block_job_do_finalize(job);
+ }
}
/* Assumes the block_job_mutex is held */
@@ -677,6 +692,15 @@ void block_job_complete(BlockJob *job, Error **errp)
job->driver->complete(job, errp);
}
+void block_job_finalize(BlockJob *job, Error **errp)
+{
+ assert(job && job->id && job->txn);
+ if (block_job_apply_verb(job, BLOCK_JOB_VERB_FINALIZE, errp)) {
+ return;
+ }
+ block_job_do_finalize(job);
+}
+
void block_job_dismiss(BlockJob **jobptr, Error **errp)
{
BlockJob *job = *jobptr;
@@ -727,11 +751,15 @@ void block_job_cancel(BlockJob *job)
{
if (job->status == BLOCK_JOB_STATUS_CONCLUDED) {
block_job_do_dismiss(job);
- } else if (block_job_started(job)) {
- block_job_cancel_async(job);
- block_job_enter(job);
- } else {
+ return;
+ }
+ block_job_cancel_async(job);
+ if (!block_job_started(job)) {
block_job_completed(job, -ECANCELED);
+ } else if (job->deferred_to_main_loop) {
+ block_job_completed_txn_abort(job);
+ } else {
+ block_job_enter(job);
}
}
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 7c8d51effa..978274ed2b 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -244,6 +244,23 @@ void block_job_cancel(BlockJob *job);
*/
void block_job_complete(BlockJob *job, Error **errp);
+
+/**
+ * block_job_finalize:
+ * @job: The job to fully commit and finish.
+ * @errp: Error object.
+ *
+ * For jobs that have finished their work and are pending
+ * awaiting explicit acknowledgement to commit their work,
+ * This will commit that work.
+ *
+ * FIXME: Make the below statement universally true:
+ * For jobs that support the manual workflow mode, all graph
+ * changes that occur as a result will occur after this command
+ * and before a successful reply.
+ */
+void block_job_finalize(BlockJob *job, Error **errp);
+
/**
* block_job_dismiss:
* @job: The job to be dismissed.
diff --git a/qapi/block-core.json b/qapi/block-core.json
index a3e64bb392..53ec9c31e9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -975,10 +975,13 @@
#
# @dismiss: see @block-job-dismiss
#
+# @finalize: see @block-job-finalize
+#
# Since: 2.12
##
{ 'enum': 'BlockJobVerb',
- 'data': ['cancel', 'pause', 'resume', 'set-speed', 'complete', 'dismiss' ] }
+ 'data': ['cancel', 'pause', 'resume', 'set-speed', 'complete', 'dismiss',
+ 'finalize' ] }
##
# @BlockJobStatus:
@@ -2278,6 +2281,24 @@
{ 'command': 'block-job-dismiss', 'data': { 'id': 'str' } }
##
+# @block-job-finalize:
+#
+# Once a job that has manual=true reaches the pending state, it can be
+# instructed to finalize any graph changes and do any necessary cleanup
+# via this command.
+# For jobs in a transaction, instructing one job to finalize will force
+# ALL jobs in the transaction to finalize, so it is only necessary to instruct
+# a single member job to finalize.
+#
+# @id: The job identifier.
+#
+# Returns: Nothing on success
+#
+# Since: 2.12
+##
+{ 'command': 'block-job-finalize', 'data': { 'id': 'str' } }
+
+##
# @BlockdevDiscardOptions:
#
# Determines how to handle discard requests.