Am 17.05.2010 12:19, schrieb MORITA Kazutaka:
> When snapshot handlers are not defined in the format driver, it is
> better to call the ones of the protocol driver. This enables us to
> implement snapshot support in the protocol driver.
>
> We need to call bdrv_close() and bdrv_open() handlers of the format
> driver before and after bdrv_snapshot_goto() call of the protocol. It is
> because the contents of the block driver state may need to be changed
> after loading vmstate.
>
> Signed-off-by: MORITA Kazutaka <morita.kazutaka@xxxxxxxxxxxxx>
> ---
> block.c | 61 +++++++++++++++++++++++++++++++++++++++++++------------------
> 1 files changed, 43 insertions(+), 18 deletions(-)
>
> diff --git a/block.c b/block.c
> index f3bf3f2..c987e57 100644
> --- a/block.c
> +++ b/block.c
> @@ -1683,9 +1683,11 @@ int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
> BlockDriver *drv = bs->drv;
> if (!drv)
> return -ENOMEDIUM;
> - if (!drv->bdrv_save_vmstate)
> - return -ENOTSUP;
> - return drv->bdrv_save_vmstate(bs, buf, pos, size);
> + if (drv->bdrv_save_vmstate)
> + return drv->bdrv_save_vmstate(bs, buf, pos, size);
> + if (bs->file)
> + return bdrv_save_vmstate(bs->file, buf, pos, size);
> + return -ENOTSUP;
> }
>
> int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
> @@ -1694,9 +1696,11 @@ int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
> BlockDriver *drv = bs->drv;
> if (!drv)
> return -ENOMEDIUM;
> - if (!drv->bdrv_load_vmstate)
> - return -ENOTSUP;
> - return drv->bdrv_load_vmstate(bs, buf, pos, size);
> + if (drv->bdrv_load_vmstate)
> + return drv->bdrv_load_vmstate(bs, buf, pos, size);
> + if (bs->file)
> + return bdrv_load_vmstate(bs->file, buf, pos, size);
> + return -ENOTSUP;
> }
>
> void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event)
> @@ -1720,20 +1724,37 @@ int bdrv_snapshot_create(BlockDriverState *bs,
> BlockDriver *drv = bs->drv;
> if (!drv)
> return -ENOMEDIUM;
> - if (!drv->bdrv_snapshot_create)
> - return -ENOTSUP;
> - return drv->bdrv_snapshot_create(bs, sn_info);
> + if (drv->bdrv_snapshot_create)
> + return drv->bdrv_snapshot_create(bs, sn_info);
> + if (bs->file)
> + return bdrv_snapshot_create(bs->file, sn_info);
> + return -ENOTSUP;
> }
>
> int bdrv_snapshot_goto(BlockDriverState *bs,
> const char *snapshot_id)
> {
> BlockDriver *drv = bs->drv;
> + int ret, open_ret;
> +
> if (!drv)
> return -ENOMEDIUM;
> - if (!drv->bdrv_snapshot_goto)
> - return -ENOTSUP;
> - return drv->bdrv_snapshot_goto(bs, snapshot_id);
> + if (drv->bdrv_snapshot_goto)
> + return drv->bdrv_snapshot_goto(bs, snapshot_id);
> +
> + if (bs->file) {
> + drv->bdrv_close(bs);
> + ret = bdrv_snapshot_goto(bs->file, snapshot_id);
> + open_ret = drv->bdrv_open(bs, bs->open_flags);
> + if (open_ret < 0) {
> + bdrv_delete(bs);
I think you mean bs->file here.
Kevin
> + bs->drv = NULL;
> + return open_ret;
> + }
> + return ret;
> + }
> +
> + return -ENOTSUP;
> }
>
> int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
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