Re: [Qemu-devel] [PATCH v13 10/14] qmp: Add command 'blockdev-backup'

["Benoît Canet" <benoit.canet@irqsave.net>]

The Monday 17 Feb 2014 à 21:32:51 (+0800), Fam Zheng wrote :
> On Thu, 02/13 14:48, Benoît Canet wrote:
> > The Wednesday 29 Jan 2014 à 13:07:37 (+0800), Fam Zheng wrote :
> > > Similar to drive-backup, but this command uses a device id as target
> > > instead of creating/opening an image file.
> > > 
> > > Also add blocker on target bs, since the target is also a named device
> > > now.
> > > 
> > > Add check and report error for bs == target which became possible but is
> > > an illegal case with introduction of blockdev-backup.
> > > 
> > > Signed-off-by: Fam Zheng <famz@redhat.com>
> > > ---
> > >  block/backup.c   | 26 ++++++++++++++++++++++++++
> > >  blockdev.c       | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> > >  qapi-schema.json | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
> > >  qmp-commands.hx  | 44 ++++++++++++++++++++++++++++++++++++++++++++
> > >  4 files changed, 166 insertions(+)
> > > 
> > > diff --git a/block/backup.c b/block/backup.c
> > > index 15a2e55..ea46340 100644
> > > --- a/block/backup.c
> > > +++ b/block/backup.c
> > > @@ -344,6 +344,7 @@ static void coroutine_fn backup_run(void *opaque)
> > >      hbitmap_free(job->bitmap);
> > >  
> > >      bdrv_iostatus_disable(target);
> > > +    bdrv_op_unblock_all(target, job->common.blocker);
> > >      bdrv_unref(target);
> > >  
> > >      block_job_completed(&job->common, ret);
> > > @@ -362,6 +363,11 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
> > >      assert(target);
> > >      assert(cb);
> > >  
> > > +    if (bs == target) {
> > > +        error_setg(errp, "Source and target cannot be the same");
> > > +        return;
> > > +    }
> > > +
> > >      if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
> > >           on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
> > >          !bdrv_iostatus_is_enabled(bs)) {
> > > @@ -369,6 +375,24 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
> > >          return;
> > >      }
> > >  
> > > +    if (!bdrv_is_inserted(bs)) {
> > > +        error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, bs->device_name);
> > > +        return;
> > > +    }
> > > +
> > > +    if (!bdrv_is_inserted(target)) {
> > > +        error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, target->device_name);
> > > +        return;
> > > +    }
> > > +
> > > +    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
> > > +        return;
> > > +    }
> > > +
> > > +    if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
> > > +        return;
> > > +    }
> > > +
> > >      len = bdrv_getlength(bs);
> > >      if (len < 0) {
> > >          error_setg_errno(errp, -len, "unable to get length for '%s'",
> > > @@ -382,6 +406,8 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
> > >          return;
> > >      }
> > >  
> > > +    bdrv_op_block_all(target, job->common.blocker);
> > > +
> > >      job->on_source_error = on_source_error;
> > >      job->on_target_error = on_target_error;
> > >      job->target = target;
> > > diff --git a/blockdev.c b/blockdev.c
> > > index ffaa6a9..b346cc1 100644
> > > --- a/blockdev.c
> > > +++ b/blockdev.c
> > > @@ -1940,6 +1940,8 @@ void qmp_drive_backup(const char *device, const char *target,
> > >          return;
> > >      }
> > >  
> > > +    /* Although backup_run has this check too, we need to use bs->drv below, so
> > > +     * do an early check redundantly. */
> > >      if (!bdrv_is_inserted(bs)) {
> > >          error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
> > >          return;
> > > @@ -1956,6 +1958,7 @@ void qmp_drive_backup(const char *device, const char *target,
> > >          }
> > >      }
> > >  
> > > +    /* Early check to avoid creating target */
> > >      if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
> > >          return;
> > >      }
> > > @@ -2019,6 +2022,50 @@ BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
> > >      return bdrv_named_nodes_list();
> > >  }
> > >  
> > > +void qmp_blockdev_backup(const char *device, const char *target,
> > > +                         enum MirrorSyncMode sync,
> > > +                         bool has_speed, int64_t speed,
> > > +                         bool has_on_source_error,
> > > +                         BlockdevOnError on_source_error,
> > > +                         bool has_on_target_error,
> > > +                         BlockdevOnError on_target_error,
> > > +                         Error **errp)
> > > +{
> > > +    BlockDriverState *bs;
> > > +    BlockDriverState *target_bs;
> > > +    Error *local_err = NULL;
> > > +
> > > +    if (!has_speed) {
> > > +        speed = 0;
> > > +    }
> > > +    if (!has_on_source_error) {
> > > +        on_source_error = BLOCKDEV_ON_ERROR_REPORT;
> > > +    }
> > > +    if (!has_on_target_error) {
> > > +        on_target_error = BLOCKDEV_ON_ERROR_REPORT;
> > > +    }
> > > +
> > > +    bs = bdrv_find(device);
> > This and the qmp prototype should be upgraded to the new device and node-name
> > alternative and make use of bdrv_lookup_bs().
> > 
> 
> Can we do it later in a separate patch?
sure.

> 
> Fam
>