Re: [Qemu-devel] [PATCH V15 02/13] quorum: Create BDRVQuorumState and BlkDriver and do init.

[Kevin Wolf <kwolf@redhat.com>]

Am 03.02.2014 um 22:51 hat Benoît Canet geschrieben:
> From: Benoît Canet <benoit@irqsave.net>
> 
> Signed-off-by: Benoit Canet <benoit@irqsave.net>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/quorum.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/block/quorum.c b/block/quorum.c
> index 17695d6..157efdf 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -15,6 +15,16 @@
>  
>  #include "block/block_int.h"
>  
> +/* the following structure holds the state of one quorum instance */
> +typedef struct {

The convention is to have both a struct name and a typedef name (and
it should be the same in both places, of course).

> +    BlockDriverState **bs; /* children BlockDriverStates */
> +    int total;             /* children count */

num_children? "total" could be anything.

> +    int threshold;         /* if less than threshold children reads gave the
> +                            * same result a quorum error occurs.
> +                            */
> +    bool is_blkverify;     /* true if the driver is in blkverify mode */

Can you describe in detail, what blkverify mode is?

> +} BDRVQuorumState;
> +
>  typedef struct QuorumAIOCB QuorumAIOCB;
>  
>  /* Quorum will create one instance of the following structure per operation it
> @@ -37,6 +47,7 @@ typedef struct QuorumSingleAIOCB {
>   */
>  struct QuorumAIOCB {
>      BlockDriverAIOCB common;
> +    BDRVQuorumState *bqs;
>  
>      /* Request metadata */
>      uint64_t sector_num;
> @@ -52,3 +63,17 @@ struct QuorumAIOCB {
>      bool is_read;
>      int vote_ret;
>  };
> +
> +static BlockDriver bdrv_quorum = {
> +    .format_name        = "quorum",
> +    .protocol_name      = "quorum",
> +
> +    .instance_size      = sizeof(BDRVQuorumState),
> +};
> +
> +static void bdrv_quorum_init(void)
> +{
> +    bdrv_register(&bdrv_quorum);
> +}
> +
> +block_init(bdrv_quorum_init);

I suspect that trying to use the driver will cause segfaults in this
state (has neither bdrv_open nor bdrv_file_open). But okay, we can live
with that.

Kevin