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

[Juergen Gross <jgross@xxxxxxxx>]

On 24.06.21 12:28, Julien Grall wrote:
> Hi Juergen,
>
> On 24/06/2021 10:41, Juergen Gross wrote:
> > On 16.06.21 16:43, Julien Grall 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>
> > > ---
> > >   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,
> > > +                        conststruct 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) {
> > Please add a comment here that the following if() serves especially to
> > avoid dumping the data for do_lu_start().
> Would you be happy to give your acked-by/reviewed-by if I add the 
> following on commit?
> "
> We only want to preserve commands that wasn't processed at all. All the 

s/wasn't/weren't/

> other delayed requests (such as do_lu_start()) must be processed before 
> Live-Update.
> "
With that change I'm fine.


Juergen

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