| Message ID | 20181215135324.152629-14-eblake@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | nbd: add qemu-nbd --list | expand |
On Sat, Dec 15, 2018 at 07:53:15AM -0600, Eric Blake wrote: > Refactor nbd_negotiate_simple_meta_context() to pull out the > code that can be reused to send a LIST request for 0 or 1 query. > No semantic change. > > Signed-off-by: Eric Blake <eblake@redhat.com> > > --- > v2: split patch into easier-to-review pieces [Rich, Vladimir] > --- > nbd/client.c | 64 ++++++++++++++++++++++++++++++++++-------------- > nbd/trace-events | 2 +- > 2 files changed, 46 insertions(+), 20 deletions(-) > > diff --git a/nbd/client.c b/nbd/client.c > index b6a85fc3ef8..5b6b9964097 100644 > --- a/nbd/client.c > +++ b/nbd/client.c > @@ -627,6 +627,48 @@ static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, > return QIO_CHANNEL(tioc); > } > > +/* nbd_send_one_meta_context: > + * Send 0 or 1 set/list meta context queries. > + * return 0 on success, -1 with errp set for any error > + */ > +static int nbd_send_one_meta_context(QIOChannel *ioc, > + uint32_t opt, > + const char *export, > + const char *query, > + Error **errp) > +{ > + int ret; > + uint32_t export_len = strlen(export); > + uint32_t queries = !!query; > + uint32_t context_len = 0; > + uint32_t data_len; > + char *data; > + char *p; > + > + data_len = sizeof(export_len) + export_len + sizeof(queries); > + if (query) { > + context_len = strlen(query); > + data_len += sizeof(context_len) + context_len; > + } else { > + assert(opt == NBD_OPT_LIST_META_CONTEXT); > + } > + data = g_malloc(data_len); > + p = data; > + > + trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export); > + stl_be_p(p, export_len); > + memcpy(p += sizeof(export_len), export, export_len); > + stl_be_p(p += export_len, queries); > + if (query) { > + stl_be_p(p += sizeof(uint32_t), context_len); > + memcpy(p += sizeof(context_len), query, context_len); > + } > + > + ret = nbd_send_option_request(ioc, opt, data_len, data, errp); > + g_free(data); > + return ret; > +} > + > /* nbd_negotiate_simple_meta_context: > * Request the server to set the meta context for export @info->name > * using @info->x_dirty_bitmap with a fallback to "base:allocation", > @@ -651,26 +693,10 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, > NBDOptionReply reply; > const char *context = info->x_dirty_bitmap ?: "base:allocation"; > bool received = false; > - uint32_t export_len = strlen(info->name); > - uint32_t context_len = strlen(context); > - uint32_t data_len = sizeof(export_len) + export_len + > - sizeof(uint32_t) + /* number of queries */ > - sizeof(context_len) + context_len; > - char *data = g_malloc(data_len); > - char *p = data; > > - trace_nbd_opt_meta_request(context, info->name); > - stl_be_p(p, export_len); > - memcpy(p += sizeof(export_len), info->name, export_len); > - stl_be_p(p += export_len, 1); > - stl_be_p(p += sizeof(uint32_t), context_len); > - memcpy(p += sizeof(context_len), context, context_len); > - > - ret = nbd_send_option_request(ioc, NBD_OPT_SET_META_CONTEXT, data_len, data, > - errp); > - g_free(data); > - if (ret < 0) { > - return ret; > + if (nbd_send_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, > + info->name, context, errp) < 0) { > + return -1; > } > > if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply, > diff --git a/nbd/trace-events b/nbd/trace-events > index 446d10b8603..00872a6f9d4 100644 > --- a/nbd/trace-events > +++ b/nbd/trace-events > @@ -11,7 +11,7 @@ nbd_receive_query_exports_start(const char *wantname) "Querying export list for > nbd_receive_query_exports_success(const char *wantname) "Found desired export name '%s'" > nbd_receive_starttls_new_client(void) "Setting up TLS" > nbd_receive_starttls_tls_handshake(void) "Starting TLS handshake" > -nbd_opt_meta_request(const char *context, const char *export) "Requesting to set meta context %s for export %s" > +nbd_opt_meta_request(const char *optname, const char *context, const char *export) "Requesting %s %s for export %s" > nbd_opt_meta_reply(const char *context, uint32_t id) "Received mapping of context %s to id %" PRIu32 > nbd_receive_negotiate(void *tlscreds, const char *hostname) "Receiving negotiation tlscreds=%p hostname=%s" > nbd_receive_negotiate_magic(uint64_t magic) "Magic is 0x%" PRIx64 Although a straightforward refactoring, we still lost the comment /* number of queries */. I'd still perhaps like to see a bit more explanation of the layout and reasoning behind the data buffer. But anyway .. Reviewed-by: Richard W.M. Jones <rjones@redhat.com> Rich.
On 12/15/18 9:22 AM, Richard W.M. Jones wrote: > On Sat, Dec 15, 2018 at 07:53:15AM -0600, Eric Blake wrote: >> Refactor nbd_negotiate_simple_meta_context() to pull out the >> code that can be reused to send a LIST request for 0 or 1 query. >> No semantic change. >> >> Signed-off-by: Eric Blake <eblake@redhat.com> >> >> --- >> v2: split patch into easier-to-review pieces [Rich, Vladimir] >> --- >> nbd/client.c | 64 ++++++++++++++++++++++++++++++++++-------------- >> nbd/trace-events | 2 +- >> 2 files changed, 46 insertions(+), 20 deletions(-) >> + uint32_t queries = !!query; This initialization... >> + uint32_t context_len = 0; >> + uint32_t data_len; >> + char *data; >> + char *p; >> + >> + data_len = sizeof(export_len) + export_len + sizeof(queries); ...plus the fact that it is now sizeof(variable) instead of sizeof(type)... >> @@ -651,26 +693,10 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, >> NBDOptionReply reply; >> const char *context = info->x_dirty_bitmap ?: "base:allocation"; >> bool received = false; >> - uint32_t export_len = strlen(info->name); >> - uint32_t context_len = strlen(context); >> - uint32_t data_len = sizeof(export_len) + export_len + >> - sizeof(uint32_t) + /* number of queries */ ...was the reason that I dropped the comment here. The comment made sense for explaining why a sizeof(type) was being injected into data_len, >> - sizeof(context_len) + context_len; >> - char *data = g_malloc(data_len); >> - char *p = data; >> >> - trace_nbd_opt_meta_request(context, info->name); >> - stl_be_p(p, export_len); >> - memcpy(p += sizeof(export_len), info->name, export_len); >> - stl_be_p(p += export_len, 1); ...because the old code was hard-coding 1 query, while the new code uses the variable (whose value is the number of queries) rather than a hard-coding. > > Although a straightforward refactoring, we still lost the comment > /* number of queries */. I'd still perhaps like to see a bit more > explanation of the layout and reasoning behind the data buffer. Perhaps a possible improvement would be to introduce a packed struct that matches the protocol layout, instead of piece-meal constructing the struct. But I'm not sure how much effort to spend on this code. > But anyway .. > > Reviewed-by: Richard W.M. Jones <rjones@redhat.com> Thanks. I'm glad you forced me to split the v1 patch into more manageable pieces; I like how it turned out.
diff --git a/nbd/client.c b/nbd/client.c index b6a85fc3ef8..5b6b9964097 100644 --- a/nbd/client.c +++ b/nbd/client.c @@ -627,6 +627,48 @@ static QIOChannel *nbd_receive_starttls(QIOChannel *ioc, return QIO_CHANNEL(tioc); } +/* nbd_send_one_meta_context: + * Send 0 or 1 set/list meta context queries. + * return 0 on success, -1 with errp set for any error + */ +static int nbd_send_one_meta_context(QIOChannel *ioc, + uint32_t opt, + const char *export, + const char *query, + Error **errp) +{ + int ret; + uint32_t export_len = strlen(export); + uint32_t queries = !!query; + uint32_t context_len = 0; + uint32_t data_len; + char *data; + char *p; + + data_len = sizeof(export_len) + export_len + sizeof(queries); + if (query) { + context_len = strlen(query); + data_len += sizeof(context_len) + context_len; + } else { + assert(opt == NBD_OPT_LIST_META_CONTEXT); + } + data = g_malloc(data_len); + p = data; + + trace_nbd_opt_meta_request(nbd_opt_lookup(opt), query ?: "(all)", export); + stl_be_p(p, export_len); + memcpy(p += sizeof(export_len), export, export_len); + stl_be_p(p += export_len, queries); + if (query) { + stl_be_p(p += sizeof(uint32_t), context_len); + memcpy(p += sizeof(context_len), query, context_len); + } + + ret = nbd_send_option_request(ioc, opt, data_len, data, errp); + g_free(data); + return ret; +} + /* nbd_negotiate_simple_meta_context: * Request the server to set the meta context for export @info->name * using @info->x_dirty_bitmap with a fallback to "base:allocation", @@ -651,26 +693,10 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, NBDOptionReply reply; const char *context = info->x_dirty_bitmap ?: "base:allocation"; bool received = false; - uint32_t export_len = strlen(info->name); - uint32_t context_len = strlen(context); - uint32_t data_len = sizeof(export_len) + export_len + - sizeof(uint32_t) + /* number of queries */ - sizeof(context_len) + context_len; - char *data = g_malloc(data_len); - char *p = data; - trace_nbd_opt_meta_request(context, info->name); - stl_be_p(p, export_len); - memcpy(p += sizeof(export_len), info->name, export_len); - stl_be_p(p += export_len, 1); - stl_be_p(p += sizeof(uint32_t), context_len); - memcpy(p += sizeof(context_len), context, context_len); - - ret = nbd_send_option_request(ioc, NBD_OPT_SET_META_CONTEXT, data_len, data, - errp); - g_free(data); - if (ret < 0) { - return ret; + if (nbd_send_one_meta_context(ioc, NBD_OPT_SET_META_CONTEXT, + info->name, context, errp) < 0) { + return -1; } if (nbd_receive_option_reply(ioc, NBD_OPT_SET_META_CONTEXT, &reply, diff --git a/nbd/trace-events b/nbd/trace-events index 446d10b8603..00872a6f9d4 100644 --- a/nbd/trace-events +++ b/nbd/trace-events @@ -11,7 +11,7 @@ nbd_receive_query_exports_start(const char *wantname) "Querying export list for nbd_receive_query_exports_success(const char *wantname) "Found desired export name '%s'" nbd_receive_starttls_new_client(void) "Setting up TLS" nbd_receive_starttls_tls_handshake(void) "Starting TLS handshake" -nbd_opt_meta_request(const char *context, const char *export) "Requesting to set meta context %s for export %s" +nbd_opt_meta_request(const char *optname, const char *context, const char *export) "Requesting %s %s for export %s" nbd_opt_meta_reply(const char *context, uint32_t id) "Received mapping of context %s to id %" PRIu32 nbd_receive_negotiate(void *tlscreds, const char *hostname) "Receiving negotiation tlscreds=%p hostname=%s" nbd_receive_negotiate_magic(uint64_t magic) "Magic is 0x%" PRIx64
Refactor nbd_negotiate_simple_meta_context() to pull out the code that can be reused to send a LIST request for 0 or 1 query. No semantic change. Signed-off-by: Eric Blake <eblake@redhat.com> --- v2: split patch into easier-to-review pieces [Rich, Vladimir] --- nbd/client.c | 64 ++++++++++++++++++++++++++++++++++-------------- nbd/trace-events | 2 +- 2 files changed, 46 insertions(+), 20 deletions(-)