Re: [PATCH 09/10] tools/xenstored: Dump delayed requests

[Luca Fancellu <luca.fancellu@xxxxxxx>]

> On 16 Jun 2021, at 15:43, Julien Grall <julien@xxxxxxx> wrote:
> 
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> Currently, only Live-Update request can be delayed. In a follow-up,
> we will want to delay more requests (e.g. transaction start).
> Therefore we want to preserve delayed requests across Live-Update.
> 
> Delayed requests are just complete "in" buffer. So the code is
> refactored to allow sharing the code to dump "in" buffer.
> 
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx>

> ---
> tools/xenstore/xenstored_core.c | 42 +++++++++++++++++++++++++--------
> 1 file changed, 32 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
> index 5b7ab7f74013..9eca58682b51 100644
> --- a/tools/xenstore/xenstored_core.c
> +++ b/tools/xenstore/xenstored_core.c
> @@ -2403,25 +2403,47 @@ const char *dump_state_global(FILE *fp)
>       return NULL;
> }
> 
> +static const char *dump_input_buffered_data(FILE *fp,
> +                                         const struct buffered_data *in,
> +                                         unsigned int *total_len)
> +{
> +     unsigned int hlen = in->inhdr ? in->used : sizeof(in->hdr);
> +
> +     *total_len += hlen;
> +     if (fp && fwrite(&in->hdr, hlen, 1, fp) != 1)
> +             return "Dump read data error";
> +     if (!in->inhdr && in->used) {
> +             *total_len += in->used;
> +             if (fp && fwrite(in->buffer, in->used, 1, fp) != 1)
> +                     return "Dump read data error";
> +     }
> +
> +     return NULL;
> +}
> +
> /* Called twice: first with fp == NULL to get length, then for writing data. 
> */
> const char *dump_state_buffered_data(FILE *fp, const struct connection *c,
>                                    struct xs_state_connection *sc)
> {
>       unsigned int len = 0, used;
> -     struct buffered_data *out, *in = c->in;
> +     struct buffered_data *out;
>       bool partial = true;
> +     struct delayed_request *req;
> +     const char *ret;
> 
> -     if (in) {
> -             len = in->inhdr ? in->used : sizeof(in->hdr);
> -             if (fp && fwrite(&in->hdr, len, 1, fp) != 1)
> -                     return "Dump read data error";
> -             if (!in->inhdr && in->used) {
> -                     len += in->used;
> -                     if (fp && fwrite(in->buffer, in->used, 1, fp) != 1)
> -                             return "Dump read data error";
> -             }
> +     /* Dump any command that was delayed */
> +     list_for_each_entry(req, &c->delayed, list) {
> +             if (req->func != process_delayed_message)
> +                     continue;
> +
> +             assert(!req->in->inhdr);
> +             if ((ret = dump_input_buffered_data(fp, req->in, &len)))
> +                     return ret;
>       }
> 
> +     if (c->in && (ret = dump_input_buffered_data(fp, c->in, &len)))
> +             return ret;
> +
>       if (sc) {
>               sc->data_in_len = len;
>               sc->data_resp_len = 0;
> -- 
> 2.17.1
> 
>