Re: [Qemu-devel] [RFC V4 3/9] quorum: Add quorum_open() and quorum_close().

[Blue Swirl]

On Mon, Aug 20, 2012 at 11:47 AM, Benoît Canet <address@hidden> wrote:
> Valid quorum resources look like:
> quorum:threshold/total:path/to/image_1: ... :path/to/image_total
>
> '\' can escape the ':' character.
>
> Signed-off-by: Benoit Canet <address@hidden>
> ---
>  block/quorum.c |  110 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 110 insertions(+)
>
> diff --git a/block/quorum.c b/block/quorum.c
> index 19a9a44..70e7216 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -52,11 +52,121 @@ struct QuorumAIOCB {
>      int vote_ret;
>  };
>
> +/* Valid quorum resources look like
> + * quorum:threshold/total:path/to/image_1: ... :path/to/image_total
> + */
> +static int quorum_open(BlockDriverState *bs, const char *filename, int flags)
> +{
> +    BDRVQuorumState *s = bs->opaque;
> +    int i, j, len, ret = 0;
> +    char *a, *b, *names;
> +    bool escape;
> +
> +    /* Parse the quorum: prefix */
> +    if (strncmp(filename, "quorum:", strlen("quorum:"))) {
> +        return -EINVAL;
> +    }
> +
> +    filename += strlen("quorum:");
> +
> +    /* Get n */

Here's still 'n' instead of threshold.

> +    errno = 0;
> +    s->threshold = strtoul(filename, &a, 10);
> +    if (*a != '/' || errno) {
> +        return -EINVAL;
> +    }
> +    a++;
> +
> +    /* Get m */

Also 'm' here.

> +    errno = 0;
> +    s->total = strtoul(a, &b, 10);
> +    if (*b != ':' || errno) {
> +        return -EINVAL;
> +    }
> +    b++;
> +
> +    if (s->threshold < 1 || s->total < 2) {
> +        return -EINVAL;
> +    }
> +
> +    if (s->threshold > s->total) {
> +        return -EINVAL;
> +    }
> +
> +    s->bs = g_malloc0(sizeof(BlockDriverState *) * s->total);
> +    /* Two allocations for all filenames: simpler to free */
> +    s->filenames = g_malloc0(sizeof(char *) * s->total);
> +    names = g_strdup(b);
> +
> +    /* Get the filenames pointers */
> +    escape = false;
> +    s->filenames[0] = names;
> +    len = strlen(names);
> +    for (i = 0, j = 1; i < len && j < s->total; i++) {
> +        if (!escape && names[i] == ':') {
> +            names[i] = '\0';
> +            s->filenames[j] = names + i + 1;
> +            j++;
> +        }
> +
> +        escape = !escape && names[i] == '\\';
> +    }
> +
> +    if (j != s->total) {
> +        ret = -EINVAL;
> +        goto free_exit;
> +    }
> +
> +    /* Open files */
> +    for (i = 0; i < s->total; i++) {
> +        s->bs[i] = bdrv_new("");
> +        ret = bdrv_open(s->bs[i], s->filenames[i], flags, NULL);
> +        if (ret < 0) {
> +            goto error_exit;
> +        }
> +    }
> +
> +    goto exit;
> +
> +error_exit:
> +    for (; i >= 0; i--) {
> +        bdrv_delete(s->bs[i]);
> +        s->bs[i] = NULL;
> +    }
> +free_exit:
> +    g_free(s->filenames[0]);
> +    g_free(s->filenames);
> +    s->filenames = NULL;
> +    g_free(s->bs);
> +exit:
> +    return ret;
> +}
> +
> +static void quorum_close(BlockDriverState *bs)
> +{
> +    BDRVQuorumState *s = bs->opaque;
> +    int i;
> +
> +    for (i = 0; i < s->total; i++) {
> +        /* Ensure writes reach stable storage */
> +        bdrv_flush(s->bs[i]);
> +        bdrv_delete(s->bs[i]);
> +    }
> +
> +    g_free(s->filenames[0]);
> +    g_free(s->filenames);
> +    s->filenames = NULL;
> +    g_free(s->bs);
> +}
> +
>  static BlockDriver bdrv_quorum = {
>      .format_name        = "quorum",
>      .protocol_name      = "quorum",
>
>      .instance_size      = sizeof(BDRVQuorumState),
> +
> +    .bdrv_file_open     = quorum_open,
> +    .bdrv_close         = quorum_close,
>  };
>
>  static void bdrv_quorum_init(void)
> --
> 1.7.9.5
>