Re: [Qemu-devel] [PATCH v2 7/9] qmp: Add dirty-bitmap-enable and dirty-bitmap-disable

[Fam Zheng]

On Thu, 03/13 14:55, Benoît Canet wrote:
> The Wednesday 12 Mar 2014 à 14:31:02 (+0800), Fam Zheng wrote :
> > This allows to put the dirty bitmap into a disabled state where no more
> > writes will be tracked.
> > 
> > It will be used before backup or writing to persistent file.
> > 
> > Signed-off-by: Fam Zheng <address@hidden>
> > ---
> >  block.c               | 15 +++++++++++++++
> >  blockdev.c            | 44 ++++++++++++++++++++++++++++++++++++++++++++
> >  include/block/block.h |  2 ++
> >  qapi-schema.json      | 32 ++++++++++++++++++++++++++++++++
> >  qmp-commands.hx       | 10 ++++++++++
> >  5 files changed, 103 insertions(+)
> > 
> > diff --git a/block.c b/block.c
> > index 199a465..1530fd1 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -55,6 +55,7 @@ struct BdrvDirtyBitmap {
> >      int64_t size;
> >      int64_t granularity;
> >      char *name;
> > +    bool enabled;
> >      QLIST_ENTRY(BdrvDirtyBitmap) list;
> >  };
> >  
> > @@ -5120,6 +5121,7 @@ BdrvDirtyBitmap 
> > *bdrv_create_dirty_bitmap(BlockDriverState *bs,
> >      if (name) {
> >          bitmap->name = g_strdup(name);
> >      }
> > +    bitmap->enabled = true;
> >      QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
> >      return bitmap;
> >  }
> > @@ -5138,6 +5140,16 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, 
> > BdrvDirtyBitmap *bitmap)
> >      }
> >  }
> >  
> > +void bdrv_disable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap 
> > *bitmap)
> > +{
> > +    bitmap->enabled = false;
> > +}
> > +
> > +void bdrv_enable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap 
> > *bitmap)
> > +{
> > +    bitmap->enabled = true;
> > +}
> > +
> >  BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
> >  {
> >      BdrvDirtyBitmap *bm;
> > @@ -5186,6 +5198,9 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t 
> > cur_sector,
> >  {
> >      BdrvDirtyBitmap *bitmap;
> >      QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
> > +        if (!bitmap->enabled) {
> > +            continue;
> > +        }
> >          hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> >      }
> >  }
> > diff --git a/blockdev.c b/blockdev.c
> > index 662c950..aa3ee55 100644
> > --- a/blockdev.c
> > +++ b/blockdev.c
> > @@ -1773,6 +1773,50 @@ void qmp_dirty_bitmap_remove(const char *device, 
> > const char *name,
> >      bdrv_release_dirty_bitmap(bs, bitmap);
> >  }
> >  
> > +void qmp_dirty_bitmap_enable(const char *device, const char *name,
> 
> > +                             bool has_granularity, int64_t granularity,
> What is the use of this line ?

Not useful for this command, but it's good to make the bitmap friends family
reuse the same data (DirtyBitmap, see below), especially for transaction
support.

> 
> > +                             Error **errp)
> > +{
> > +    BlockDriverState *bs;
> > +    BdrvDirtyBitmap *bitmap;
> > +
> > +    bs = bdrv_find(device);
> > +    if (!bs) {
> > +        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> > +        return;
> > +    }
> > +
> > +    bitmap = bdrv_find_dirty_bitmap(bs, name);
> > +    if (!bitmap) {
> > +        error_setg(errp, "Dirty bitmap not found: %s", name);
> > +        return;
> > +    }
> > +
> > +    bdrv_enable_dirty_bitmap(bs, bitmap);
> > +}
> > +
> > +void qmp_dirty_bitmap_disable(const char *device, const char *name,
> 
> > +                              bool has_granularity, int64_t granularity,
> Same question ?

Same answer :)

> 
> > +                              Error **errp)
> > +{
> > +    BlockDriverState *bs;
> > +    BdrvDirtyBitmap *bitmap;
> > +
> > +    bs = bdrv_find(device);
> > +    if (!bs) {
> > +        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> > +        return;
> > +    }
> > +
> > +    bitmap = bdrv_find_dirty_bitmap(bs, name);
> > +    if (!bitmap) {
> > +        error_setg(errp, "Dirty bitmap not found: %s", name);
> > +        return;
> > +    }
> > +
> > +    bdrv_disable_dirty_bitmap(bs, bitmap);
> > +}
> > +
> >  int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
> >  {
> >      const char *id = qdict_get_str(qdict, "id");
> > diff --git a/include/block/block.h b/include/block/block.h
> > index 66aae57..2875d7d 100644
> > --- a/include/block/block.h
> > +++ b/include/block/block.h
> > @@ -449,6 +449,8 @@ BdrvDirtyBitmap 
> > *bdrv_copy_dirty_bitmap(BlockDriverState *bs,
> >                                          const BdrvDirtyBitmap *bitmap,
> >                                          const char *name);
> >  void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap 
> > *bitmap);
> > +void bdrv_disable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap 
> > *bitmap);
> > +void bdrv_enable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap 
> > *bitmap);
> >  BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
> >  int bdrv_dirty_bitmap_granularity(BlockDriverState *bs,
> >                                    BdrvDirtyBitmap *bitmap);
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 632bb10..f8cd6b8 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -2225,6 +2225,38 @@
> >    'data': { 'device': 'str', 'name': 'str' } }
> >  
> >  ##
> > +# @dirty-bitmap-enable
> > +#
> > +# Enable a dirty bitmap on the device
> > +#
> > +# Setting granularity has no effect here.
> > +#
> > +# Returns: nothing on success
> > +#          If @device is not a valid block device, DeviceNotFound
> > +#          If @name is not found, GenericError with an explaining message
> > +#
> > +# Since 2.1
> > +##
> > +{'command': 'dirty-bitmap-enable',
> > +  'data': 'DirtyBitmap' }
> > +
> > +##
> > +# @dirty-bitmap-disable
> > +#
> > +# Disable a dirty bitmap on the device
> > +#
> > +# Setting granularity has no effect here.
> > +#
> > +# Returns: nothing on success
> > +#          If @device is not a valid block device, DeviceNotFound
> > +#          If @name is not found, GenericError with an explaining message
> > +#
> > +# Since 2.1
> > +##
> > +{'command': 'dirty-bitmap-disable',
> > +  'data': 'DirtyBitmap' }
> 
> Granularity is not defined on the QMP interface. Does it even compile ?

Yes it is defined in DirtyBitmap. See patch 2.

Thanks,
Fam