search for: nbd_set_opt_mode

...ed. As coded in this patch, state Negotiating can only be reached from a newstyle-fixed server (not even a plain newstyle server will get here, since that must go straight to NBD_OPT_EXPORT_NAME which has no error detection short of killing the connection). So our options after the user calls nbd_set_opt_mode(nbd, true) are: 1. silently proceed to nbd_aio_is_ready; the user never got a chance to reach Negotiating, and can readily deduce that this was because the server didn't support negotiation. The lack of negotiation does not stop the user from using the export. 2. error out at the magic nu...

I think this needs extra documentation in docs/libnbd.pod because it's definitely not clear just from the rather thin manual page for set_opt_mode how it works. docs/libnbd.pod is a good place for a broader description of how it works. IIUC let me try to explain: we get through as far as the end of group OPT_STRUCTURED_REPLY before we check the opt flag, and then the remainder of opt

On 8/11/20 12:12 PM, Richard W.M. Jones wrote: > I think this needs extra documentation in docs/libnbd.pod because it's > definitely not clear just from the rather thin manual page for > set_opt_mode how it works. docs/libnbd.pod is a good place for a > broader description of how it works. Yes, good idea. State-wise, the existing flow was: Created - Progress only by command

...of the earlier patches are ready to commit while I continue working on the latter half. Eric Blake (13): api: Add nbd_set_full_info and friends info: Improve info without --list api: Add nbd_is_state_negotiating for new state api: Permit several existing API in Negotiating state api: Add nbd_set_opt_mode api: Add nbd_opt_abort and nbd_aio_opt_abort api: Add nbd_opt_go and nbd_aio_opt_go examples: Update list-exports to demonstrate nbd_opt_go info: Simplify by using nbd_opt_go api: Add nbd_opt_list api: Add nbd_aio_opt_list wip: api: Give aio_opt_go a completion callback wip: api: ad...

This is the bare minimum needed to allow the user to take control over the rest of option negotiating. This patch adds several new API: nbd_set_opt_mode() - called during Created to enable the new mode nbd_get_opt_mode() - query whether opt mode is enabled nbd_opt_go() - used in Negotiating state to attempt to use export nbd_opt_abort() - used in Negotiating state to skip Connected state nbd_aio_is_negotiating() - used to detect Negotiating state...

...e mode 100644 generator/states-newstyle-opt-extended-headers.c diff --git a/generator/API.ml b/generator/API.ml index 36033817..d1849710 100644 --- a/generator/API.ml +++ b/generator/API.ml @@ -953,23 +953,24 @@ "set_request_meta_context", { (all C<nbd_connect_*> calls when L<nbd_set_opt_mode(3)> is false, or L<nbd_opt_go(3)> and L<nbd_opt_info(3)> when option mode is enabled) will also try to issue NBD_OPT_SET_META_CONTEXT when -the server supports structured replies and any contexts were -registered by L<nbd_add_meta_context(3)>. The default setting -is true; h...

...sing opt mode to alter the export. */ - name = export_list.names[i]; - nbd2 = nbd_create (); - if (nbd2 == NULL) { - fprintf (stderr, "%s\n", nbd_get_error ()); - exit (EXIT_FAILURE); - } - nbd_set_uri_allow_local_file (nbd2, true); /* Allow ?tls-psk-file. */ - nbd_set_opt_mode (nbd2, true); + if (probe_content) { + /* Connect to the original URI, but using opt mode to alter the export. */ + nbd2 = nbd_create (); + if (nbd2 == NULL) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + nbd_set_uri_...

...File "/usr/lib64/python3.8/code.py", line 90, in runcode exec(code, self.locals) File "<console>", line 1, in <module> File "/home/eblake/libnbd/python/nbd.py", line 570, in set_opt_mode return libnbdmod.set_opt_mode (self._o, enable) nbd.Error: nbd_set_opt_mode: invalid state: NEGOTIATING: the handle must be newly created: Invalid argument (EINVAL) nbd> quit() --- generator/API.ml | 12 ++++++++++-- generator/states-newstyle-opt-go.c | 19 +++++++++++++------ lib/opt.c | 18 ++++++++++++++++-- 3 files changed...

...security issues found in this release. If you find a security issue, please read SECURITY in the source (online here: https://github.com/libguestfs/libnbd/blob/master/SECURITY). To find out about previous security issues in libnbd, see libnbd-security(3). New APIs nbd_set_opt_mode(3) nbd_get_opt_mode(3) nbd_aio_is_negotiating(3) libnbd 1.4 adds a new “negotiating” state during NBD handshaking. For backwards compatibility programs must request this before starting the connection by calling nbd_set_opt_mode(3). You can...

...ll with + args = []; ret = RErr; + permitted_states = [ Negotiating ]; + shortdesc = "end negotiation and close the connection"; + longdesc = "\ +Request that the server finish negotiation, gracefully if possible, then +close the connection. This can only be used if L<nbd_set_opt_mode(3)> +enabled option mode."; + example = Some "examples/list-exports.c"; + see_also = [Link "set_opt_mode"; Link "aio_opt_abort"]; + }; + "set_list_exports", { default_call with args = [Bool "list"]; ret = RErr; @@ -1883,6...

This replaces 13/13 of my v2 series; and now that it has pretty good testsuite coverage and demonstrable performance improvement to nbdinfo, I'm going ahead and pushing this now. We may still want to add further nbd_opt_* commands for other fine-grained tuning of negotiation, but for now, I think things have stabilized on this end, and I can return to polishing .list_exports on the nbdkit

...static void list_one_export (struct nbd_handle *nbd, const char *desc, @@ -207,10 +213,10 @@ main (int argc, char *argv[]) nbd_set_uri_allow_local_file (nbd, true); /* Allow ?tls-psk-file. */ /* Set optional modes in the handle. */ - if (list_all) + if (!map && !size_only) { nbd_set_opt_mode (nbd, true); - if (!map && !size_only) nbd_set_full_info (nbd, true); + } if (map) nbd_add_meta_context (nbd, map); @@ -320,10 +326,32 @@ main (int argc, char *argv[]) } free (export_list.names); free (export_list.descs); + nbd_opt_abort (nbd); + nbd_shutdown (nbd...

In v2: ack'ed preliminary patches have been pushed, and I've added a lot of testsuite coverage as well as putting the new API to use in nbdinfo. Eric Blake (2): api: Add nbd_opt_list_meta_context info: List available meta-contexts lib/internal.h | 1 + generator/API.ml | 84 ++++++++-

...equest the server to list available meta contexts"; + longdesc = "\ +Request that the server list available meta contexts associated with +the export previously specified by the most recent +L<nbd_set_export_name(3)> or L<nbd_connect_uri(3)>. This can only be +used if L<nbd_set_opt_mode(3)> enabled option mode. + +The NBD protocol allows a client to decide how many queries to ask +the server. Rather than taking that list of queries as a parameter +to this function, libnbd reuses the current list of requested meta +contexts as set by L<nbd_add_meta_context(3)>; you can us...

...Connect to the original URI, but using opt mode to alter the export. */ + nbd2 = nbd_create (); + if (nbd2 == NULL) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + nbd_set_uri_allow_local_file (nbd2, true); /* Allow ?tls-psk-file. */ + nbd_set_opt_mode (nbd2, true); - if (nbd_connect_uri (nbd2, new_uri) == -1) { - fprintf (stderr, "%s\n", nbd_get_error ()); - exit (EXIT_FAILURE); - } + if (nbd_connect_uri (nbd2, uri) == -1 || + nbd_set_export_name (nbd2, name) == -1 || + nbd_opt_go (nbd2) == -1)...

I'm posting this now, as I'm at the end of a workday and I got things working for manual experimentation. Still to do: - write interop tests for qemu-nbd and nbdkit (including my proposed patch addition of qemu-nbd -A to show qemu:allocation-depth) - figure out if we can make 'nbdinfo --map' use the new API to automatically select all contexts advertised by the server Eric Blake

These patches aren't related to each other, but both are quite simple. The second one requires particular attention - it's my experience that printing out the state transitions in debug mode has never helped me to diagnose a bug, but it has made the debug logs huge and hard to follow. However that might just be me! Has it helped anyone else? Also I'm open to the concept of debug

This is a subset of my v2 posting, but limited to just the NBD_OPT_LIST handling. The biggest change since v2 is the addition of added unit testing in all four language bindings (C, python, ocaml, golang). The tests require nbdkit built from git on PATH, and may not be entirely idiomatic, but I at least validated that they catch issues (for example, adding an exit statement near the end of the

Another series on top of my exportname filter, marking off another todo bullet point. With this, you can now use the NBD plugin as a transparent passthrough of all export names served by the remote server in both directions (list advertisement server to client, and export name from client to server). Eric Blake (3): nbd: Implement .default_export, .export_description nbd: Add

...> +this is whether blocks of data are allocated, zero or sparse). + +This command resets the list of meta contexts to request back to +an empty list, for re-population by further use of +L<nbd_add_meta_context(3)>. It is primarily useful when option +negotiation mode is selected (see L<nbd_set_opt_mode(3)>), for +altering the list of attempted contexts between subsequent export +queries."; + see_also = [Link "block_status"; Link "can_meta_context"; + Link "add_meta_context"; Link "get_nr_meta_contexts"; + Link "...