Re: [Qemu-devel] [PATCH 3/6] block: Extract blockdev part of qmp_drive_mirror

[Max Reitz <mreitz@redhat.com>]

On 09.06.2015 04:13, Fam Zheng wrote:
> This is the part that will be reused by blockdev-mirror.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>   blockdev.c | 158 +++++++++++++++++++++++++++++++++++--------------------------
>   1 file changed, 92 insertions(+), 66 deletions(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index b573e56..c32a9a9 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2883,29 +2883,22 @@ out:
>   
>   #define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
>   
> -void qmp_drive_mirror(const char *device, const char *target,
> -                      bool has_format, const char *format,
> -                      bool has_node_name, const char *node_name,
> -                      bool has_replaces, const char *replaces,
> -                      enum MirrorSyncMode sync,
> -                      bool has_mode, enum NewImageMode mode,
> -                      bool has_speed, int64_t speed,
> -                      bool has_granularity, uint32_t granularity,
> -                      bool has_buf_size, int64_t buf_size,
> -                      bool has_on_source_error, BlockdevOnError on_source_error,
> -                      bool has_on_target_error, BlockdevOnError on_target_error,
> -                      Error **errp)
> +/* Parameter check and block job starting for mirroring.
> + * Caller should hold @device and @target's aio context (They must to be on the
> + * same aio context). */
> +static void blockdev_mirror_common(BlockDriverState *bs,
> +                                   BlockDriverState *target,
> +                                   bool has_replaces, const char *replaces,
> +                                   enum MirrorSyncMode sync,
> +                                   bool has_speed, int64_t speed,
> +                                   bool has_granularity, uint32_t granularity,
> +                                   bool has_buf_size, int64_t buf_size,
> +                                   bool has_on_source_error,
> +                                   BlockdevOnError on_source_error,
> +                                   bool has_on_target_error,
> +                                   BlockdevOnError on_target_error,
> +                                   Error **errp)
>   {
> -    BlockBackend *blk;
> -    BlockDriverState *bs;
> -    BlockDriverState *source, *target_bs;
> -    AioContext *aio_context;
> -    BlockDriver *drv = NULL;
> -    Error *local_err = NULL;
> -    QDict *options = NULL;
> -    int flags;
> -    int64_t size;
> -    int ret;
>   
>       if (!has_speed) {
>           speed = 0;
> @@ -2916,9 +2909,6 @@ void qmp_drive_mirror(const char *device, const char *target,
>       if (!has_on_target_error) {
>           on_target_error = BLOCKDEV_ON_ERROR_REPORT;
>       }
> -    if (!has_mode) {
> -        mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
> -    }
>       if (!has_granularity) {
>           granularity = 0;
>       }
> @@ -2936,35 +2926,73 @@ void qmp_drive_mirror(const char *device, const char *target,
>           return;
>       }
>   
> -    blk = blk_by_name(device);
> -    if (!blk) {
> -        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> -        return;
> -    }
> -
> -    aio_context = blk_get_aio_context(blk);
> -    aio_context_acquire(aio_context);
> -
> -    if (!blk_is_available(blk)) {
> -        error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
> -        goto out;
> -    }
> -    bs = blk_bs(blk);
> -
> -    if (!has_format) {
> -        format = mode == NEW_IMAGE_MODE_EXISTING ? NULL : bs->drv->format_name;
> -    }
> -    if (format) {
> -        drv = bdrv_find_format(format);
> -        if (!drv) {
> -            error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
> -            goto out;
> -        }
> -    }
> -
>       if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR_SOURCE, errp)) {
> +        return;
> +    }
> +
> +    if (!bs->backing_hd && sync == MIRROR_SYNC_MODE_TOP) {
> +        sync = MIRROR_SYNC_MODE_FULL;
> +    }
> +
> +    /* pass the node name to replace to mirror start since it's loose coupling
> +     * and will allow to check whether the node still exist at mirror completion
> +     */
> +    mirror_start(bs, target,
> +                 has_replaces ? replaces : NULL,
> +                 speed, granularity, buf_size, sync,
> +                 on_source_error, on_target_error,
> +                 block_job_cb, bs, errp);
> +}
> +
> +void qmp_drive_mirror(const char *device, const char *target,
> +                      bool has_format, const char *format,
> +                      bool has_node_name, const char *node_name,
> +                      bool has_replaces, const char *replaces,
> +                      enum MirrorSyncMode sync,
> +                      bool has_mode, enum NewImageMode mode,
> +                      bool has_speed, int64_t speed,
> +                      bool has_granularity, uint32_t granularity,
> +                      bool has_buf_size, int64_t buf_size,
> +                      bool has_on_source_error, BlockdevOnError on_source_error,
> +                      bool has_on_target_error, BlockdevOnError on_target_error,
> +                      Error **errp)
> +{
> +    BlockDriverState *bs;
> +    BlockBackend *blk;
> +    BlockDriverState *source, *target_bs;
> +    AioContext *aio_context;
> +    BlockDriver *drv = NULL;
> +    Error *local_err = NULL;
> +    QDict *options = NULL;
> +    int flags;
> +    int64_t size;
> +    int ret;
> +
> +    blk = blk_by_name(device);
> +    if (!blk) {
> +        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
> +        return;
> +    }
> +
> +    aio_context = blk_get_aio_context(blk);
> +    aio_context_acquire(aio_context);
> +
> +    if (!blk_is_available(blk)) {
> +        error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
>           goto out;
>       }
> +    bs = blk_bs(blk);
> +
> +    if (!has_format) {
> +        format = mode == NEW_IMAGE_MODE_EXISTING ? NULL : bs->drv->format_name;
> +    }
> +    if (format) {
> +        drv = bdrv_find_format(format);
> +        if (!drv) {
> +            error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
> +            goto out;
> +        }
> +    }
>   
>       flags = bs->open_flags | BDRV_O_RDWR;
>       source = bs->backing_hd;
> @@ -2989,14 +3017,14 @@ void qmp_drive_mirror(const char *device, const char *target,
>           if (!has_node_name) {
>               error_setg(errp, "a node-name must be provided when replacing a"
>                                " named node of the graph");
> -            goto out;
> +            return;
>           }
>   
>           to_replace_bs = check_to_replace_node(replaces, &local_err);
>   
>           if (!to_replace_bs) {
>               error_propagate(errp, local_err);
> -            goto out;
> +            return;
>           }
>   
>           replace_aio_context = bdrv_get_aio_context(to_replace_bs);
> @@ -3007,7 +3035,7 @@ void qmp_drive_mirror(const char *device, const char *target,
>           if (size != replace_size) {
>               error_setg(errp, "cannot replace image with a mirror image of "
>                                "different size");
> -            goto out;
> +            return;
>           }
>       }

There are still a couple of "return;" statements left in the "if 
(has_replaces)" block. I think they should be replaced, too.

Max