Re: [Qemu-devel] [PATCH] block/create: Do not abort if a block driver is not available

[Eric Blake <eblake@redhat.com>]

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On 9/11/19 5:08 PM, Philippe Mathieu-Daudé wrote:
> The 'blockdev-create' QMP command was introduced as experimental
> feature in commit b0292b851b8, using the assert() debug call.
> It got promoted to 'stable' command in 3fb588a0f2c, but the
> assert call was not removed.
> 
> Some block drivers are optional, and bdrv_find_format() might
> return a NULL value, triggering the assertion.
> 
> Stable code is not expected to abort, so return an error instead.
> 

> 
> Reported-by: Xu Tian <xutian@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  block/create.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/block/create.c b/block/create.c
> index 1bd00ed5f8..89812669df 100644
> --- a/block/create.c
> +++ b/block/create.c
> @@ -64,9 +64,13 @@ void qmp_blockdev_create(const char *job_id, BlockdevCreateOptions *options,
>      const char *fmt = BlockdevDriver_str(options->driver);
>      BlockDriver *drv = bdrv_find_format(fmt);
>  
> +    if (!drv) {
> +        error_setg(errp, "Block driver '%s' not found or not supported", fmt);
> +        return;
> +    }
> +
>      /* If the driver is in the schema, we know that it exists. But it may not
>       * be whitelisted. */
> -    assert(drv);
>      if (bdrv_uses_whitelist() && !bdrv_is_whitelisted(drv, false)) {
>          error_setg(errp, "Driver is not whitelisted");

Matches that we error for not being on the whitelist.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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