block: add support for job pause/resume
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 <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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:
