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[Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'blo
From: |
Kashyap Chamarthy |
Subject: |
[Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel' |
Date: |
Wed, 15 Nov 2017 10:09:47 +0100 |
When you cancel an in-progress live block operation with QMP
`block-job-cancel`, it emits the event: BLOCK_JOB_CANCELLED. However,
when `block-job-cancel` is issued after `drive-mirror` has indicated (by
emitting the event BLOCK_JOB_READY) that the source and destination
remain synchronized:
[...] # Snip `drive-mirror` invocation & outputs
{
"execute":"block-job-cancel",
"arguments":{
"device":"virtio0"
}
}
{"return": {}}
It (`block-job-cancel`) will counterintuitively emit the event
'BLOCK_JOB_COMPLETED':
{
"timestamp":{
"seconds":1510678024,
"microseconds":526240
},
"event":"BLOCK_JOB_COMPLETED",
"data":{
"device":"virtio0",
"len":41126400,
"offset":41126400,
"speed":0,
"type":"mirror"
}
}
But this is expected behaviour, where the _COMPLETED event indicates
that synchronization has successfully ended (and the destination has a
point-in-time copy, which is at the time of cancel).
So add a small note to this effect. (Thanks: Max Reitz for reminding
me of this on IRC.)
Signed-off-by: Kashyap Chamarthy <address@hidden>
---
Changes in v2:
- "Note:" seems to be a special construct in Patchew, my usage caused a
build failure. So do: s/Note:/Note that/
- Add the missing 'Signed-off-by'
---
qapi/block-core.json | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index
ab96e348e6317bb42769ae20f4a4519bac02e93a..4ecfd1fbc5bc231c69da15d489c44e3e8b0706a5
100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2065,6 +2065,14 @@
# BLOCK_JOB_CANCELLED event. Before that happens the job is still visible when
# enumerated using query-block-jobs.
#
+# Note that the 'block-job-cancel' command will emit the event
+# BLOCK_JOB_COMPLETED if you issue it ('block-job-cancel') after 'drive-mirror'
+# has indicated (by emitting the event BLOCK_JOB_READY) that the source and
+# destination remain synchronized. In this case, the BLOCK_JOB_COMPLETED
+# event indicates that synchronization (from 'drive-mirror') has successfully
+# ended and the destination now has a point-in-time copy, which is at the time
+# of cancel.
+#
# For streaming, the image file retains its backing file unless the streaming
# operation happens to complete just as it is being cancelled. A new streaming
# operation can be started at a later time to finish copying all data from the
--
2.9.5
- [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel',
Kashyap Chamarthy <=
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', John Snow, 2017/11/15
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', Kashyap Chamarthy, 2017/11/15
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', John Snow, 2017/11/15
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', Kashyap Chamarthy, 2017/11/16
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', John Snow, 2017/11/16
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', Kevin Wolf, 2017/11/17
- Re: [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel', Kashyap Chamarthy, 2017/11/17