For 32-bit block status, we were able to cheat and use an array with an odd number of elements, with array[0] holding the context id, and passing &array[1] to the user's callback. But once we have 64-bit extents, we can no longer abuse array element 0 like that. Split out a new state to receive the context id separately from the extents array. No behavioral change, other than the rare possibility of landing in the new state. --- lib/internal.h | 1 + generator/state_machine.ml | 11 +++++- generator/states-reply-structured.c | 58 ++++++++++++++++++++--------- 3 files changed, 51 insertions(+), 19 deletions(-)
diff --git a/lib/internal.h b/lib/internal.h index 0e205aba..7e96e8e9 100644 --- a/lib/internal.h +++ b/lib/internal.h @@ -274,6 +274,7 @@ struct nbd_handle { size_t querynum; /* When receiving block status, this is used. */ + uint32_t bs_contextid; uint32_t *bs_entries; /* Commands which are waiting to be issued [meaning the request diff --git a/generator/state_machine.ml b/generator/state_machine.ml index 3bc77f24..99652948 100644 --- a/generator/state_machine.ml +++ b/generator/state_machine.ml @@ -1,6 +1,6 @@ (* hey emacs, this is OCaml code: -*- tuareg -*- *) (* nbd client library in userspace: state machine definition - * Copyright (C) 2013-2020 Red Hat Inc. + * Copyright (C) 2013-2021 Red Hat Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -862,10 +862,17 @@ and external_events = []; }; + State { + default_state with + name = "RECV_BS_CONTEXTID"; + comment = "Receive contextid of structured reply block-status payload"; + external_events = []; + }; + State { default_state with name = "RECV_BS_ENTRIES"; - comment = "Receive a structured reply block-status payload"; + comment = "Receive entries array of structured reply block-status payload"; external_events = []; }; diff --git a/generator/states-reply-structured.c b/generator/states-reply-structured.c index 70010474..e1da850d 100644 --- a/generator/states-reply-structured.c +++ b/generator/states-reply-structured.c @@ -1,5 +1,5 @@ /* nbd client library in userspace: state machine - * Copyright (C) 2013-2019 Red Hat Inc. + * Copyright (C) 2013-2021 Red Hat Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -185,19 +185,10 @@ STATE_MACHINE { set_error (0, "not expecting NBD_REPLY_TYPE_BLOCK_STATUS here"); return 0; } - /* We read the context ID followed by all the entries into a - * single array and deal with it at the end. - */ - free (h->bs_entries); - h->bs_entries = malloc (length); - if (h->bs_entries == NULL) { - SET_NEXT_STATE (%.DEAD); - set_error (errno, "malloc"); - return 0; - } - h->rbuf = h->bs_entries; - h->rlen = length; - SET_NEXT_STATE (%RECV_BS_ENTRIES); + /* Start by reading the context ID. */ + h->rbuf = &h->bs_contextid; + h->rlen = sizeof h->bs_contextid; + SET_NEXT_STATE (%RECV_BS_CONTEXTID); return 0; } else { @@ -452,9 +443,41 @@ STATE_MACHINE { } return 0; + REPLY.STRUCTURED_REPLY.RECV_BS_CONTEXTID: + struct command *cmd = h->reply_cmd; + uint32_t length; + + switch (recv_into_rbuf (h)) { + case -1: SET_NEXT_STATE (%.DEAD); return 0; + case 1: + save_reply_state (h); + SET_NEXT_STATE (%.READY); + return 0; + case 0: + length = be32toh (h->sbuf.sr.structured_reply.length); + + assert (cmd); /* guaranteed by CHECK */ + assert (cmd->type == NBD_CMD_BLOCK_STATUS); + assert (length >= 12); + length -= sizeof h->bs_contextid; + + free (h->bs_entries); + h->bs_entries = malloc (length); + if (h->bs_entries == NULL) { + SET_NEXT_STATE (%.DEAD); + set_error (errno, "malloc"); + return 0; + } + h->rbuf = h->bs_entries; + h->rlen = length; + SET_NEXT_STATE (%RECV_BS_ENTRIES); + } + return 0; + REPLY.STRUCTURED_REPLY.RECV_BS_ENTRIES: struct command *cmd = h->reply_cmd; uint32_t length; + uint32_t count; size_t i; uint32_t context_id; struct meta_context *meta_context; @@ -473,15 +496,16 @@ STATE_MACHINE { assert (CALLBACK_IS_NOT_NULL (cmd->cb.fn.extent)); assert (h->bs_entries); assert (length >= 12); + count = (length - sizeof h->bs_contextid) / sizeof *h->bs_entries; /* Need to byte-swap the entries returned, but apart from that we * don't validate them. */ - for (i = 0; i < length/4; ++i) + for (i = 0; i < count; ++i) h->bs_entries[i] = be32toh (h->bs_entries[i]); /* Look up the context ID. */ - context_id = h->bs_entries[0]; + context_id = be32toh (h->bs_contextid); for (meta_context = h->meta_contexts; meta_context; meta_context = meta_context->next) @@ -494,7 +518,7 @@ STATE_MACHINE { if (CALL_CALLBACK (cmd->cb.fn.extent, meta_context->name, cmd->offset, - &h->bs_entries[1], (length-4) / 4, + h->bs_entries, count, &error) == -1) if (cmd->error == 0) cmd->error = error ? error : EPROTO; -- 2.33.1