Re: [Libguestfs] [PATCH v4 15/24] nbd/server: Prepare to send extended header replies

On 08.06.23 16:56, Eric Blake wrote: > Although extended mode is not yet enabled, once we do turn it on, we > need to reply with extended headers to all messages. Update the low > level entry points necessary so that all other callers automatically > get the right header based on the current mode. > > Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; > --- > > v4: new patch, split out from v3 9/14 > --- > nbd/server.c | 30 ++++++++++++++++++++++-------- > 1 file changed, 22 insertions(+), 8 deletions(-) > > diff --git a/nbd/server.c b/nbd/server.c > index 119ac765f09..84c848a31d3 100644 > --- a/nbd/server.c > +++ b/nbd/server.c > @@ -1947,8 +1947,6 @@ static inline void set_be_chunk(NBDClient *client, struct iovec *iov, > size_t niov, uint16_t flags, uint16_t type, > NBDRequest *request) > { > - /* TODO - handle structured vs. extended replies */ > - NBDStructuredReplyChunk *chunk = iov->iov_base; > size_t i, length = 0; > > for (i = 1; i < niov; i++) { > @@ -1956,12 +1954,26 @@ static inline void set_be_chunk(NBDClient *client, struct iovec *iov, > } > assert(length <= NBD_MAX_BUFFER_SIZE + sizeof(NBDStructuredReadData)); > > - iov[0].iov_len = sizeof(*chunk); > - stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); > - stw_be_p(&chunk->flags, flags); > - stw_be_p(&chunk->type, type); > - stq_be_p(&chunk->cookie, request->cookie); > - stl_be_p(&chunk->length, length); > + if (client->mode >= NBD_MODE_EXTENDED) { > + NBDExtendedReplyChunk *chunk = iov->iov_base; > + > + iov->iov_len = sizeof(*chunk); I'd prefer to keep iov[0].iov_len notation, to stress that iov is an array anyway: Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru&gt;

> + stl_be_p(&chunk->magic, NBD_EXTENDED_REPLY_MAGIC); > + stw_be_p(&chunk->flags, flags); > + stw_be_p(&chunk->type, type); > + stq_be_p(&chunk->cookie, request->cookie); Hm. Not about this patch: we now moved to simple cookies. And it seems that actually, 64bit is too much for number of request.