The Saturday 02 Aug 2014 à 01:49:15 (+0200), Max Reitz wrote :
> Depending on the changed options and the image format,
> bdrv_amend_options() may take a significant amount of time. In these
> cases, a way to be informed about the operation's status is desirable.
>
> Since the operation is rather complex and may fundamentally change the
> image, implementing it as AIO or a couroutine does not seem feasible. On
> the other hand, implementing it as a block job would be significantly
> more difficult than a simple callback and would not add benefits other
> than progress report to the amending operation, because it should not
> actually be run as a block job at all.
>
> A callback may not be very pretty, but it's very easy to implement and
> perfectly fits its purpose here.
>
> Signed-off-by: Max Reitz <mre...@redhat.com>
> ---
> block.c | 5 +++--
> block/qcow2.c | 3 ++-
> include/block/block.h | 8 +++++++-
> include/block/block_int.h | 3 ++-
> qemu-img.c | 2 +-
> 5 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/block.c b/block.c
> index 3e252a2..4c8d4d8 100644
> --- a/block.c
> +++ b/block.c
> @@ -5708,12 +5708,13 @@ void bdrv_add_before_write_notifier(BlockDriverState
> *bs,
> notifier_with_return_list_add(&bs->before_write_notifiers, notifier);
> }
>
> -int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts)
> +int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts,
> + BlockDriverAmendStatusCB *status_cb)
> {
> if (!bs->drv->bdrv_amend_options) {
> return -ENOTSUP;
> }
> - return bs->drv->bdrv_amend_options(bs, opts);
> + return bs->drv->bdrv_amend_options(bs, opts, status_cb);
> }
>
> /* This function will be called by the bdrv_recurse_is_first_non_filter
> method
> diff --git a/block/qcow2.c b/block/qcow2.c
> index b0faa69..a3a7efc 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2210,7 +2210,8 @@ static int qcow2_downgrade(BlockDriverState *bs, int
> target_version)
> return 0;
> }
>
> -static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts)
> +static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
> + BlockDriverAmendStatusCB *status_cb)
> {
> BDRVQcowState *s = bs->opaque;
> int old_version = s->qcow_version, new_version = old_version;
> diff --git a/include/block/block.h b/include/block/block.h
> index 32d3676..3ce3076 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -309,7 +309,13 @@ typedef enum {
>
> int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode
> fix);
>
> -int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts);
> +/* The units of offset and total_work_size may be chosen arbitrarily by the
> + * block driver; total_work_size may change during the course of the
> amendment
> + * operation */
> +typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
> + int64_t total_work_size);
> +int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
> + BlockDriverAmendStatusCB *status_cb);
>
> /* external snapshots */
> bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index f6c3bef..5c5798d 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -228,7 +228,8 @@ struct BlockDriver {
> int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
> BdrvCheckMode fix);
>
> - int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts);
> + int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts,
> + BlockDriverAmendStatusCB *status_cb);
>
> void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
>
> diff --git a/qemu-img.c b/qemu-img.c
> index ef74ae4..90d6b79 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -2827,7 +2827,7 @@ static int img_amend(int argc, char **argv)
> goto out;
> }
>
> - ret = bdrv_amend_options(bs, opts);
> + ret = bdrv_amend_options(bs, opts, NULL);
> if (ret < 0) {
> error_report("Error while amending options: %s", strerror(-ret));
> goto out;
> --
> 2.0.3
>
Reviewed-by: Benoit Canet <ben...@irqsave.net>
