Re: [Qemu-devel] [RFC V2 03/10] quorum: Add quorum_open().

[Blue Swirl]

On Tue, Aug 7, 2012 at 1:44 PM, Benoît Canet <address@hidden> wrote:
> Signed-off-by: Benoit Canet <address@hidden>
> ---
>  block/quorum.c |   62 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 62 insertions(+)
>
> diff --git a/block/quorum.c b/block/quorum.c
> index e0405b6..de58ab8 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -47,11 +47,73 @@ struct QuorumAIOCB {
>      int vote_ret;
>  };
>
> +/* Valid quorum filenames look like
> + * quorum:path/to/a_image:path/to/b_image:path/to/c_image

This syntax would mean that stacking for example curl or other network
paths would not be possible. How about comma as separator?

> + */
> +static int quorum_open(BlockDriverState *bs, const char *filename, int flags)
> +{
> +    BDRVQuorumState *s = bs->opaque;
> +    int ret, i;
> +    char *a, *b, *c, *filenames[3];
> +
> +    /* Parse the quorum: prefix */
> +    if (strncmp(filename, "quorum:", strlen("quorum:"))) {
> +        return -EINVAL;
> +    }
> +    a = g_strdup(filename + strlen("quorum:"));
> +
> +    /* Find separators */
> +    b = strchr(a, ':');
> +    if (b == NULL) {
> +        return -EINVAL;
> +    }
> +
> +    c = strrchr(a, ':');
> +    if (c == NULL) {
> +        return -EINVAL;
> +    }
> +
> +    /* Check that filename contains two separate ':' */
> +    if (b == c) {
> +        return -EINVAL;
> +    }
> +
> +    /* Split string */
> +    *b = '\0';
> +    *c = '\0';
> +
> +    filenames[0] = a;
> +    filenames[1] = b + 1;
> +    filenames[2] = c + 1;
> +
> +    /* Open files */
> +    for (i = 0; i <= 2; i++) {
> +        s->bs[i] = bdrv_new("");
> +        ret = bdrv_open(s->bs[i], filenames[i], flags, NULL);
> +        if (ret < 0) {
> +            goto error_exit;

Successfully opening two out of three should be enough, but maybe it
does not make much sense.

> +        }
> +    }
> +
> +    goto clean_exit;
> +
> +error_exit:
> +    for (; i >= 0; i--) {
> +        bdrv_delete(s->bs[i]);

bdrv_close() instead?

> +        s->bs[i] = NULL;
> +    }
> +clean_exit:
> +    g_free(a);
> +    return ret;
> +}
> +
>  static BlockDriver bdrv_quorum = {
>      .format_name        = "quorum",
>      .protocol_name      = "quorum",
>
>      .instance_size      = sizeof(BDRVQuorumState),
> +
> +    .bdrv_file_open     = quorum_open,
>  };
>
>  static void bdrv_quorum_init(void)
> --
> 1.7.9.5
>