Re: [Qemu-devel] [PATCH COLO v3 11/14] Backup: clear all bitmap when doing block checkpoint

[Paolo Bonzini <pbonzini@redhat.com>]

On 03/04/2015 12:01, Wen Congyang wrote:
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> Cc: Jeff Cody <jcody@redhat.com>
> ---
>  block/backup.c           | 13 +++++++++++++
>  blockjob.c               | 10 ++++++++++
>  include/block/blockjob.h | 12 ++++++++++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/block/backup.c b/block/backup.c
> index 1c535b1..e8b8931 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -208,11 +208,24 @@ static void backup_iostatus_reset(BlockJob *job)
>      bdrv_iostatus_reset(s->target);
>  }
>  
> +static void backup_do_checkpoint(BlockJob *job, Error **errp)
> +{
> +    BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
> +
> +    if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) {
> +        error_setg(errp, "this feature or command is not currently supported");
> +        return;
> +    }
> +
> +    hbitmap_reset_all(backup_job->bitmap);
> +}
> +
>  static const BlockJobDriver backup_job_driver = {
>      .instance_size  = sizeof(BackupBlockJob),
>      .job_type       = BLOCK_JOB_TYPE_BACKUP,
>      .set_speed      = backup_set_speed,
>      .iostatus_reset = backup_iostatus_reset,
> +    .do_checkpoint  = backup_do_checkpoint,
>  };
>  
>  static BlockErrorAction backup_error_action(BackupBlockJob *job,
> diff --git a/blockjob.c b/blockjob.c
> index ba2255d..dbac81e 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -388,3 +388,13 @@ void block_job_defer_to_main_loop(BlockJob *job,
>  
>      qemu_bh_schedule(data->bh);
>  }
> +
> +void block_job_do_checkpoint(BlockJob *job, Error **errp)
> +{
> +    if (!job->driver->do_checkpoint) {
> +        error_setg(errp, "this feature or command is not currently supported");
> +        return;
> +    }
> +
> +    job->driver->do_checkpoint(job, errp);
> +}
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index b6d4ebb..c6f1cad 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -50,6 +50,9 @@ typedef struct BlockJobDriver {
>       * manually.
>       */
>      void (*complete)(BlockJob *job, Error **errp);
> +
> +    /** Optional callback for job types that support checkpoint. */
> +    void (*do_checkpoint)(BlockJob *job, Error **errp);
>  } BlockJobDriver;
>  
>  /**
> @@ -334,4 +337,13 @@ void block_job_defer_to_main_loop(BlockJob *job,
>                                    BlockJobDeferToMainLoopFn *fn,
>                                    void *opaque);
>  
> +/**
> + * block_job_do_checkpoint:
> + * @job: The job.
> + * @errp: Error object.
> + *
> + * Do block checkpoint on the specified job.
> + */
> +void block_job_do_checkpoint(BlockJob *job, Error **errp);
> +
>  #endif
> 

Does this only run on the secondary, or also on the primary?  What
happens if you use a block job on the primary?

Perhaps a variant of backup_job_driver is needed for COLO, and the
default behavior of block_job_do_checkpoint should be to do nothing?

Paolo