search for: issue_command_state_machine

...sue-command.c | 25 ++++++++++++++++++++++++- lib/internal.h | 1 + 3 files changed, 43 insertions(+), 9 deletions(-) diff --git a/generator/generator b/generator/generator index a4ad362..5c84a5d 100755 --- a/generator/generator +++ b/generator/generator @@ -620,12 +620,6 @@ and issue_command_state_machine = [ State { default_state with name = "START"; - (* XXX There's a possible deadlock here if a server cannot - * handle multiple requests pipelined on a single connection. - * We could try to issue a command and block, but reads might - * be available. It s...

...generator/states-reply.c | 5 ++++- lib/internal.h | 1 + 4 files changed, 47 insertions(+), 4 deletions(-) diff --git a/generator/generator b/generator/generator index a4ad362..23b3cbf 100755 --- a/generator/generator +++ b/generator/generator @@ -634,7 +634,15 @@ and issue_command_state_machine = [ default_state with name = "SEND_REQUEST"; comment = "Sending a request to the remote server"; - external_events = [ NotifyWrite, "" ]; + external_events = [ NotifyWrite, ""; + NotifyRead, "PAUSE_SEND_REQUES...

This might not be the final solution, but it certainly seems to solve a deadlock for me that I could trigger by using 'nbdkit --filter=noparallel memory 512k' and calling nbd_aio_pread for a request larger than 256k (enough for the Linux kernel to block the server until libnbd read()s), immediately followed by nbd_aio_pwrite for a request larger than 256k (enough to block libnbd until the

On v1, we discussed whether cmds_to_issue needed to be a list, since it never had more than one element. I played with the idea of making it a list, and allowing the client to queue up new commands regardless of whether the state machine is currently in READY. I also polished up the tmp demo into a bit more full-fledged example file, worth including since it also let me discover a hard-to-hit race

...++++++++++ generator/states-issue-command.c | 45 ++++++++++++++++++++------------ 2 files changed, 42 insertions(+), 17 deletions(-) diff --git a/generator/generator b/generator/generator index a1bf41d..a4ad362 100755 --- a/generator/generator +++ b/generator/generator @@ -637,12 +637,26 @@ and issue_command_state_machine = [ external_events = [ NotifyWrite, "" ]; }; + State { + default_state with + name = "PREPARE_WRITE_PAYLOAD"; + comment = "Prepare the write payload to send to the remote server"; + external_events = []; + }; + State { default_state with...

Since v2: - rebase to Rich's new API calls - more refactoring in patch 1 (retitled) - new patches 3 and 4 - fix data corruption in patch 6 (was 4) - more tweaks to the reproducer example (including using new API from 3) Eric Blake (7): lib: Refactor command_common() to do more common work commands: Allow for a command queue commands: Expose FIFO ordering of server completions

...E reply"; + external_events = [ NotifyRead, "" ]; + }; + + State { + default_state with + name = "CHECK_REPLY"; + comment = "Check newstyle NBD_OPT_EXPORT_NAME reply"; + external_events = []; + }; +] + (* Sending a command to the server. *) and issue_command_state_machine = [ State { diff --git a/generator/states-newstyle-opt-export-name.c b/generator/states-newstyle-opt-export-name.c new file mode 100644 index 0000000..6c6bce4 --- /dev/null +++ b/generator/states-newstyle-opt-export-name.c @@ -0,0 +1,73 @@ +/* nbd client library in userspace: state machine + * C...

nbdkit 1.2 as a server waits for read() to see EOF, even after the client has sent NBD_CMD_DISC. That was fixed in mbdkit 1.4; and most modern NBD servers are smarter than this (they close() the write end of their traffic soon after NBD_CMD_DISC). But it's easy enough to revert nbdkit commit c70616f8 to get back to a server with the same behavior as the older nbdkit, at which point both

Some of these affect attempts to connect to older qemu-nbd versions, some of them were triggered by manual edits to qemu-nbd source code to provoke various other compliant (if uncommon) server behaviors. Eric Blake (4): starttls: Skip error payload if falling back to unencrypted states: Reject payload to NBD_REP_ACK meta-context: Skip error payload if server lacks meta_context states: Add