Re: [Qemu-devel] [PATCH v2 2/9] qmp: Add dirty-bitmap-add and dirty-bitmap-remove

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

The Wednesday 12 Mar 2014 à 14:30:57 (+0800), Fam Zheng wrote :
> The new command pair is added to manage user created dirty bitmap. The
> dirty bitmap's name is mandatory and must be unique for the same device,
> but different devices can have bitmaps with the same names.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockdev.c       | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qapi-schema.json | 45 ++++++++++++++++++++++++++++++++++++++++++
>  qmp-commands.hx  | 49 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 154 insertions(+)
> 
> diff --git a/blockdev.c b/blockdev.c
> index c3422a1..662c950 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1713,6 +1713,66 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
>      }
>  }
>  
> +void qmp_dirty_bitmap_add(const char *device, const char *name,
Do we want this to work on node-names too ?

> +                          bool has_granularity, int64_t granularity,
> +                          Error **errp)
> +{
> +    BlockDriverState *bs;
> +    BdrvDirtyBitmap *bitmap;
> +
> +    bs = bdrv_find(device);
Do we want bdrv_lookup_bs here ?

> +    if (!bs) {
> +        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> +        return;
> +    }
> +
> +    if (!name || name[0] == '\0') {
> +        error_setg(errp, "Bitmap name cannot be empty");
> +        return;
> +    }
> +    if (has_granularity) {
> +        if (granularity & (granularity - 1)) {
> +            error_setg(errp, "Granularity must be power of 2");
> +            return;
> +        }
> +    } else {
> +        granularity = 65536;
> +    }
> +
> +    bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
> +    if (!bitmap) {
> +        return;
> +    }
> +}
> +
> +void qmp_dirty_bitmap_remove(const char *device, const char *name,
> +                             Error **errp)
> +{
> +    BlockDriverState *bs;
> +    BdrvDirtyBitmap *bitmap;
> +
> +    bs = bdrv_find(device);
> +    if (!bs) {
> +        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> +        return;
> +    }
> +
> +    if (!name || name[0] == '\0') {
> +        error_setg(errp, "Bitmap name cannot be empty");
> +        return;
> +    }
> +    bitmap = bdrv_find_dirty_bitmap(bs, name);
> +    if (!bitmap) {
> +        error_setg(errp, "Dirty bitmap not found: %s", name);
> +        return;
> +    }
> +
> +    /* Make it invisible to user in case the following
> +     * bdrv_release_dirty_bitmap doens't free it because of refcnt */
> +    bdrv_dirty_bitmap_make_anon(bs, bitmap);
> +    bdrv_release_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/qapi-schema.json b/qapi-schema.json
> index 4d5bc13..632bb10 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -2180,6 +2180,51 @@
>              '*on-target-error': 'BlockdevOnError' } }
>  
>  ##
> +# @DirtyBitmap
> +#
> +# @device: name of device which the bitmap is tracking
> +#
> +# @name: name of the dirty bitmap
> +#
> +# @granularity: #optional the bitmap granularity, default is 64k for
> +#               dirty-bitmap-add
> +#
> +# Since 2.1
> +##
> +{ 'type': 'DirtyBitmap',
> +  'data': { 'device': 'str', 'name': 'str', '*granularity': 'int' } }
> +
> +##
> +# @dirty-bitmap-add
> +#
> +# Create a dirty bitmap with a name on the device
> +#
> +# Returns: nothing on success
> +#          If @device is not a valid block device, DeviceNotFound
> +#          If @name is already taken, GenericError with an explaining message
> +#
> +# Since 2.1
> +##
> +{'command': 'dirty-bitmap-add',
> +  'data': 'DirtyBitmap' }
> +
> +##
> +# @dirty-bitmap-remove
> +#
> +# Remove 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-remove',
> +  'data': { 'device': 'str', 'name': 'str' } }
> +
> +##
>  # @migrate_cancel
>  #
>  # Cancel the current executing migration process.
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index d982cd6..c42516d 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -1185,6 +1185,55 @@ Example:
>  EQMP
>  
>      {
> +        .name       = "dirty-bitmap-add",
> +        .args_type  = "device:B,name:s,granularity:i?",
> +        .mhandler.cmd_new = qmp_marshal_input_dirty_bitmap_add,
> +    },
> +    {
> +        .name       = "dirty-bitmap-remove",
> +        .args_type  = "device:B,name:s",
> +        .mhandler.cmd_new = qmp_marshal_input_dirty_bitmap_remove,
> +    },
> +
> +SQMP
> +
> +dirty-bitmap-add
> +----------------
> +
> +Create a dirty bitmap with a name on the device, and start tracking the writes.
> +
> +Arguments:
> +
> +- "device": device name to create dirty bitmap (json-string)
> +- "name": name of the new dirty bitmap (json-string)
> +- "granularity": granularity to track writes with. (int)
> +
> +Example:
> +
> +-> { "execute": "dirty-bitmap-add", "arguments": { "device": "drive0",
> +                                                   "name": "bitmap0" } }
> +<- { "return": {} }
> +
> +dirty-bitmap-remove
> +----------------
> +
> +Stop write tracking and remove the dirty bitmap that was created with
s/remove the/remove a/

> +dirty-bitmap-add.
> +
> +Arguments:
> +
> +- "device": device name to remove dirty bitmap (json-string)
> +- "name": name of the dirty bitmap to remove (json-string)
> +
> +Example:
> +
> +-> { "execute": "dirty-bitmap-remove", "arguments": { "device": "drive0",
> +                                                      "name": "bitmap0" } }
> +<- { "return": {} }
> +
> +EQMP
> +
> +    {
>          .name       = "blockdev-snapshot-sync",
>          .args_type  = "device:s?,node-name:s?,snapshot-file:s,snapshot-node-name:s?,format:s?,mode:s?",
>          .mhandler.cmd_new = qmp_marshal_input_blockdev_snapshot_sync,
> -- 
> 1.9.0
> 
>