Re: [PATCH 4/9] rbd: read the header before registering device

[Josh Durgin <josh.durgin@inktank.com>]

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

On 09/07/2012 08:44 AM, Alex Elder wrote:
> Read the rbd header information and call rbd_dev_set_mapping()
> earlier--before registering the block device or setting up the sysfs
> entries for the image.  The sysfs entries provide users access to
> some information that's only available after doing the rbd header
> initialization, so this will make sure it's valid right away.
>
> Signed-off-by: Alex Elder <elder@inktank.com>
> ---
>   drivers/block/rbd.c |   31 +++++++++++++++++--------------
>   1 file changed, 17 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index d60db25..89d8ed7 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -2598,10 +2598,24 @@ static ssize_t rbd_add(struct bus_type *bus,
>   		goto err_out_client;
>   	sprintf(rbd_dev->header_name, "%s%s", rbd_dev->image_name, RBD_SUFFIX);
>
> +	/* Get information about the image being mapped */
> +
> +	rc = rbd_read_header(rbd_dev, &rbd_dev->header);
> +	if (rc)
> +		goto err_out_client;
> +
> +	rc = rbd_dev_snaps_update(rbd_dev);
> +	if (rc)
> +		goto err_out_header;
> +
> +	rc = rbd_dev_set_mapping(rbd_dev, snap_name);
> +	if (rc)
> +		goto err_out_header;
> +
>   	/* register our block device */
>   	rc = register_blkdev(0, rbd_dev->name);
>   	if (rc < 0)
> -		goto err_out_client;
> +		goto err_out_header;
>   	rbd_dev->major = rc;
>
>   	rc = rbd_bus_add_dev(rbd_dev);
> @@ -2613,19 +2627,6 @@ static ssize_t rbd_add(struct bus_type *bus,
>   	 * of the sysfs code (initiated by rbd_bus_del_dev()).
>   	 */
>
> -	/* contact OSD, request size info about the object being mapped */
> -	rc = rbd_read_header(rbd_dev, &rbd_dev->header);
> -	if (rc)
> -		goto err_out_unlock;
> -
> -	rc = rbd_dev_snaps_update(rbd_dev);
> -	if (rc)
> -		goto err_out_unlock;
> -
> -	rc = rbd_dev_set_mapping(rbd_dev, snap_name);
> -	if (rc)
> -		goto err_out_unlock;
> -
>   	rc = rbd_dev_snaps_register(rbd_dev);
>   	if (rc)
>   		goto err_out_unlock;
> @@ -2662,6 +2663,8 @@ err_out_bus:
>
>   err_out_blkdev:
>   	unregister_blkdev(rbd_dev->major, rbd_dev->name);
> +err_out_header:
> +	rbd_header_free(&rbd_dev->header);
>   err_out_client:
>   	kfree(rbd_dev->header_name);
>   	rbd_put_client(rbd_dev);
>