search for: wait_for_option

...NISHED); - break; - } + else if (h->opt_mode) + SET_NEXT_STATE (%.NEGOTIATING); + else + SET_NEXT_STATE (%^PREPARE_OPT_ABORT); return 0; } /* END STATE MACHINE */ diff --git a/lib/opt.c b/lib/opt.c index 1a5f645..17f2508 100644 --- a/lib/opt.c +++ b/lib/opt.c @@ -60,16 +60,28 @@ wait_for_option (struct nbd_handle *h) return 0; } +static int +go_complete (void *opaque, int *err) +{ + int *i = opaque; + *i = *err; + return 0; +} + /* Issue NBD_OPT_GO (or NBD_OPT_EXPORT_NAME) and wait for the reply. */ int nbd_unlocked_opt_go (struct nbd_handle *h) { - int r = nbd_unlocked_aio_o...

This is my proposal for fixing the documentation to match practice (namely, that completion.callback is not invoked in the cases where the aio call itself reports errors); we could instead try to go the other direction and tweak the generator to guarantee that both completion.callback and completion.free are reached no matter what, but that felt more invasive to me. Eric Blake (2): api: Tighten

...t nbd_handle *h) +{ + if (h->current_opt == NBD_OPT_LIST) + FREE_CALLBACK (h->opt_cb.fn.list); + FREE_CALLBACK (h->opt_cb.completion); +} + int nbd_unlocked_set_opt_mode (struct nbd_handle *h, bool value) { @@ -78,37 +87,47 @@ nbd_unlocked_opt_abort (struct nbd_handle *h) return wait_for_option (h); } +struct list_helper { + int count; + nbd_list_callback list; + int err; +}; +static int +list_visitor (void *opaque, const char *name, const char *description) +{ + struct list_helper *h = opaque; + if (h->count < INT_MAX) + h->count++; + CALL_CALLBACK (h->list, name,...

Well, I'm not quite done (I still want to get nbdinfo to work on a single nbd connection for all cases when reading the heads of the file is not required), but I'm happy with patches 1-11, and 12-13 show where I'm headed for getting NBD_OPT_INFO to work. Posting now to see if some of the earlier patches are ready to commit while I continue working on the latter half. Eric Blake (13):

...AD); + } + return 0; + NEWSTYLE.FINISHED: SET_NEXT_STATE (%.READY); return 0; diff --git a/lib/opt.c b/lib/opt.c index 306a2e9..6243553 100644 --- a/lib/opt.c +++ b/lib/opt.c @@ -39,3 +39,37 @@ nbd_unlocked_get_opt_mode (struct nbd_handle *h) { return h->opt_mode; } + +static int +wait_for_option (struct nbd_handle *h) +{ + while (nbd_internal_is_state_connecting (get_next_state (h))) { + if (nbd_unlocked_poll (h, -1) == -1) + return -1; + } + + return 0; +} + +/* Issue NBD_OPT_ABORT and wait for the state change. */ +int +nbd_unlocked_opt_abort (struct nbd_handle *h) +{ + int r...

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

...t nbd_handle *h) +{ + if (h->opt_current == NBD_OPT_LIST) + FREE_CALLBACK (h->opt_cb.fn.list); + FREE_CALLBACK (h->opt_cb.completion); +} + int nbd_unlocked_set_opt_mode (struct nbd_handle *h, bool value) { @@ -76,37 +87,47 @@ nbd_unlocked_opt_abort (struct nbd_handle *h) return wait_for_option (h); } +struct list_helper { + int count; + nbd_list_callback list; + int err; +}; +static int +list_visitor (void *opaque, const char *name, const char *description) +{ + struct list_helper *h = opaque; + if (h->count < INT_MAX) + h->count++; + CALL_CALLBACK (h->list, name,...

As promised in my earlier thread on libnbd completion callback question. Eric Blake (2): generator: Refactor handling of closures in unlocked functions generator: Free closures on failure docs/libnbd.pod | 2 +- generator/C.ml | 48 +++++++++++------ generator/C.mli | 1 + lib/debug.c | 7 +-- lib/opt.c | 31 ++++++-----

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

...--git a/lib/opt.c b/lib/opt.c index 003ecf8..6ea8326 100644 --- a/lib/opt.c +++ b/lib/opt.c @@ -156,6 +156,7 @@ nbd_unlocked_opt_list (struct nbd_handle *h, nbd_list_callback *list) if (nbd_unlocked_aio_opt_list (h, &l, &c) == -1) return -1; + SET_CALLBACK_TO_NULL (*list); if (wait_for_option (h) == -1) return -1; if (s.err) { @@ -172,6 +173,7 @@ nbd_unlocked_aio_opt_go (struct nbd_handle *h, { h->opt_current = NBD_OPT_GO; h->opt_cb.completion = *complete; + SET_CALLBACK_TO_NULL (*complete); if (nbd_internal_run (h, cmd_issue) == -1) debug (h, "option...

...bd_context_callback l = { .callback = context_visitor, .user_data = &s }; + nbd_completion_callback c = { .callback = context_complete, .user_data = &s }; + + if (nbd_unlocked_aio_opt_list_meta_context (h, &l, &c) == -1) + return -1; + + SET_CALLBACK_TO_NULL (*context); + if (wait_for_option (h) == -1) + return -1; + if (s.err) { + set_error (s.err, "server replied with error to list meta context request"); + return -1; + } + return s.count; +} + /* Issue NBD_OPT_GO (or NBD_OPT_EXPORT_NAME) without waiting. */ int nbd_unlocked_aio_opt_go (struct nbd_handle *h,...

...st }; nbd_list_callback l = { .callback = list_visitor, .user_data = &s }; nbd_completion_callback c = { .callback = list_complete, .user_data = &s }; - if (nbd_unlocked_aio_opt_list (h, l, c) == -1) + if (nbd_unlocked_aio_opt_list (h, &l, &c) == -1) return -1; if (wait_for_option (h) == -1) @@ -168,10 +168,10 @@ nbd_unlocked_opt_list (struct nbd_handle *h, nbd_list_callback list) /* Issue NBD_OPT_GO (or NBD_OPT_EXPORT_NAME) without waiting. */ int nbd_unlocked_aio_opt_go (struct nbd_handle *h, - nbd_completion_callback complete) +...

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

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 ++++++++-

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