Re: [Qemu-devel] Block job commands in QEMU 1.2 [v2, including support for replication]

[Kevin Wolf <kwolf@redhat.com>]

Am 25.05.2012 10:28, schrieb Stefan Hajnoczi:
> On Thu, May 24, 2012 at 03:41:29PM +0200, Paolo Bonzini wrote:
>> changes from v1:
>> - added per-job iostatus
>> - added description of persistent dirty bitmap
>>
>> The same content is also at
>> http://wiki.qemu.org/Features/LiveBlockMigration/1.2
>>
>>
>> QMP changes for error handling
>> ==============================
>>
>> * query-block-jobs: BlockJobInfo gets two new fields, paused and
>> io-status.  The job-specific iostatus is completely separate from the
>> block device iostatus.
>>
>>
>> * block-stream: I would still like to add on_error to the existing
>> block-stream command, if only to ease unit testing.  Concerns about the
>> stability of the API can be handled by adding introspection (exporting
>> the schema), which is not hard to do.  The new option is an enum with
>> the following possible values:
>>
>> 'report': The behavior is the same as in 1.1.  An I/O error will
>> complete the job immediately with an error code.
>>
>> 'ignore': An I/O error, respectively during a read or a write, will be
>> ignored.  For streaming, the job will complete with an error and the
>> backing file will be left in place.  For mirroring, the sector will be
>> marked again as dirty and re-examined later.
>>
>> 'stop': The job will be paused, and the job iostatus (which can be
>> examined with query-block-jobs) is updated.
>>
>> 'enospc': Behaves as 'stop' for ENOSPC errors, 'report' for others.

May I quote the next two lines as well?

"In all cases, even for 'report', the I/O error is reported as a QMP
event BLOCK_JOB_ERROR, with the same arguments as BLOCK_IO_ERROR."

> 'stop' and 'enospc' must raise a QMP event so the user is notified when
> the job is paused.  Are the details on this missing from this draft?

No, just from your quote. :-)

Kevin