From: Paolo Bonzini <pbonz...@redhat.com>
Job pausing reuses the existing support for cancellable sleeps. A pause
happens at the next sleeping point and lasts until the coroutine is
re-entered explicitly. Cancellation was already doing a forced resume,
so implement it explicitly in terms of resume.
Paused jobs cannot be canceled without first resuming them. This ensures
that I/O errors are never missed by management.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
blockdev.c | 4 ++++
blockjob.c | 35 ++++++++++++++++++++++++++++++-----
blockjob.h | 31 +++++++++++++++++++++++++++++++
qapi-schema.json | 5 ++++-
qerror.h | 3 +++
5 files changed, 72 insertions(+), 6 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 9a98ce9..612dd71 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1221,6 +1221,10 @@ void qmp_block_job_cancel(const char *device, Error
**errp)
error_set(errp, QERR_BLOCK_JOB_NOT_ACTIVE, device);
return;
}
+ if (job->paused) {
+ error_set(errp, QERR_BLOCK_JOB_PAUSED, device);
+ return;
+ }
trace_qmp_block_job_cancel(job);
block_job_cancel(job);
diff --git a/blockjob.c b/blockjob.c
index 64c9d2d..8219f73 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -99,14 +99,30 @@ void block_job_set_speed(BlockJob *job, int64_t speed,
Error **errp)
job->speed = speed;
}
-void block_job_cancel(BlockJob *job)
+void block_job_pause(BlockJob *job)
{
- job->cancelled = true;
+ job->paused = true;
+}
+
+bool block_job_is_paused(BlockJob *job)
+{
+ return job->paused;
+}
+
+void block_job_resume(BlockJob *job)
+{
+ job->paused = false;
if (job->co && !job->busy) {
qemu_coroutine_enter(job->co, NULL);
}
}
+void block_job_cancel(BlockJob *job)
+{
+ job->cancelled = true;
+ block_job_resume(job);
+}
+
bool block_job_is_cancelled(BlockJob *job)
{
return job->cancelled;
@@ -154,12 +170,20 @@ int block_job_cancel_sync(BlockJob *job)
void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns)
{
+ assert(job->busy);
+
/* Check cancellation *before* setting busy = false, too! */
- if (!block_job_is_cancelled(job)) {
- job->busy = false;
+ if (block_job_is_cancelled(job)) {
+ return;
+ }
+
+ job->busy = false;
+ if (block_job_is_paused(job)) {
+ qemu_coroutine_yield();
+ } else {
co_sleep_ns(clock, ns);
- job->busy = true;
}
+ job->busy = true;
}
BlockJobInfo *block_job_query(BlockJob *job)
@@ -169,6 +193,7 @@ BlockJobInfo *block_job_query(BlockJob *job)
info->device = g_strdup(bdrv_get_device_name(job->bs));
info->len = job->len;
info->busy = job->busy;
+ info->paused = job->paused;
info->offset = job->offset;
info->speed = job->speed;
return info;
diff --git a/blockjob.h b/blockjob.h
index f3d8d58..ece5afa 100644
--- a/blockjob.h
+++ b/blockjob.h
@@ -70,6 +70,12 @@ struct BlockJob {
bool cancelled;
/**
+ * Set to true if the job is either paused, or will pause itself
+ * as soon as possible (if busy == true).
+ */
+ bool paused;
+
+ /**
* Set to false by the job while it is in a quiescent state, where
* no I/O is pending and the job has yielded on any condition
* that is not detected by #qemu_aio_wait, such as a timer.
@@ -171,6 +177,31 @@ bool block_job_is_cancelled(BlockJob *job);
BlockJobInfo *block_job_query(BlockJob *job);
/**
+ * block_job_pause:
+ * @job: The job to be paused.
+ *
+ * Asynchronously pause the specified job.
+ */
+void block_job_pause(BlockJob *job);
+
+/**
+ * block_job_resume:
+ * @job: The job to be resumed.
+ *
+ * Resume the specified job.
+ */
+void block_job_resume(BlockJob *job);
+
+/**
+ * block_job_is_paused:
+ * @job: The job being queried.
+ *
+ * Returns whether the job is currently paused, or will pause
+ * as soon as it reaches a sleeping point.
+ */
+bool block_job_is_paused(BlockJob *job);
+
+/**
* block_job_cancel_sync:
* @job: The job to be canceled.
*
diff --git a/qapi-schema.json b/qapi-schema.json
index 6fc6eda..86a6c7f 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1101,6 +1101,9 @@
# @busy: false if the job is known to be in a quiescent state, with
# no pending I/O. Since 1.3.
#
+# @paused: whether the job is paused or, if @busy is true, will
+# pause itself as soon as possible. Since 1.3.
+#
# @offset: the current progress value
#
# @speed: the rate limit, bytes per second
@@ -1109,7 +1112,7 @@
##
{ 'type': 'BlockJobInfo',
'data': {'type': 'str', 'device': 'str', 'len': 'int',
- 'offset': 'int', 'busy': 'bool', 'speed': 'int'} }
+ 'offset': 'int', 'busy': 'bool', 'paused': 'bool', 'speed': 'int'} }
##
# @query-block-jobs:
diff --git a/qerror.h b/qerror.h
index 485c773..c91708c 100644
--- a/qerror.h
+++ b/qerror.h
@@ -51,6 +51,9 @@ void assert_no_error(Error *err);
#define QERR_BLOCK_JOB_NOT_ACTIVE \
ERROR_CLASS_DEVICE_NOT_ACTIVE, "No active block job on device '%s'"
+#define QERR_BLOCK_JOB_PAUSED \
+ ERROR_CLASS_GENERIC_ERROR, "The block job for device '%s' is currently
paused"
+
#define QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED \
ERROR_CLASS_GENERIC_ERROR, "Block format '%s' used by device '%s' does not
support feature '%s'"
--
1.7.6.5
