similar to: [PATCH libnbd] states: In recv_into_rbuf and send_from_wbuf loop until EAGAIN.

This isn't quite finished because not all of the tests or examples have been updated, but it demonstrates an idea: Should we forget about the concept of having multiple connections managed under a single handle? In this patch there is a single ‘struct nbd_handle *’ which manages a single state machine and connection (and therefore no nbd_connection). To connect to a multi-conn server you must

Previously we performed a single call to recv(2) or send(2) (or the GnuTLS equivalents), and even if more data/space was immediately available to receive/send we would return to poll. Instead of this, loop until the socket returns EAGAIN. --- generator/states.c | 91 ++++++++++++++++++++++------------------------ 1 file changed, 43 insertions(+), 48 deletions(-) diff --git a/generator/states.c

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

This works, but there's no time saving and I'm still investigating whether it does what I think it does. Nevertheless I thought I would post it because it (probably) implements the idea I had last night outlined in: https://www.redhat.com/archives/libguestfs/2019-June/msg00010.html The meat of the change is patch 4. Patch 5 is an example which I would probably fold into patch 4 for

This was v3 patch 2/22, reworked to address the confusion about how a structured reply header is read in two pieces before getting to the payload portion. I'm still working on rebasing the rest of my v3 series (patches 1, 3-22) from other comments given, but this seemed independent enough that it's worth posting now rather than holding it up for the rest of the series. Eric Blake (4):

Appears to have a measurable benefit, see 3/3 for test results. Rich.

I've mentioned this topic before (in fact, the idea of adding NBD_CMD_FLAG_DF was first mentioned at [1]), but finally finished enough of an implementation to feel confident in posting it. I'd still like to add something under examples/ that uses the new API to implement strict checking of a server's structured replies read implementation (ensure that a server never sends data after

I still need to wire in the use of *_notify functions into nbdkit to prove whether it makes the code any faster or easier to maintain, but at least the added example shows one good use case for the new API. Eric Blake (6): api: Add nbd_aio_in_flight generator: Allow DEAD state actions to run generator: Allow Int64 in callbacks states: Prepare for aio notify callback api: Add new

This set of patches fixes virt-rescue rather cleanly. In particular the problems with handling ^C are completely fixed. Work still to be done before this can go upstream: - Shutdown doesn't work properly if you exit the shell. At the moment to exit you must do 'reboot -f'. Future improvements: - An escape sequence and escape commands that could be handled by virt-rescue,

This fixes the main issues in virt-rescue and is usable. There are some enhancements which could be made (in follow up work): - An escape sequence and escape commands that could be handled by virt-rescue, eg. to shut down the appliance, mount or unmount filesystems. - `virt-rescue -i' could be implemented cleanly by performing the right API calls before handing control to the

Proposal for new APIs to list exports. The general shape of the API can probably best be seen from the examples/list-exports.c example. Rich.

Similar to the recent --mask-handshake command line added to nbdkit to test client fallbacks to crippled servers, it can be worth testing server fallbacks to crippled clients. And just as we have exposed whether the client will request structured replies, we can also expose whether the client will understand various handshake flags from the NBD protocol. Of course, we default to supporting all

I'm still playing with ideas on how to split rstate from wstate (so that we can send a request without waiting for POLLIN to complete a pending reply), but this is some preliminary refactoring I found useful. I also fixed a couple of bugs while in the area (already pushed). There's a question of whether we want nbd_handle to be nearly 5k, or if we should instead keep it small and add one

There's an obvious bug in this patch in that it doesn't reset the h->wflags field in all cases. Updated patch below. I rechecked the performance measurements and they are the same after the updated patch. Rich. >From 15a687b50acecebcfd3dc6222d93e6df984b83c6 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" <rjones@redhat.com> Date: Sat, 8 Jun 2019 19:12:22 +0100

Just a simple refactoring in preparation for forthcoming work. --- generator/states-reply.c | 2 +- generator/states.c | 4 ++-- lib/crypto.c | 5 +++-- lib/internal.h | 6 ++++-- lib/socket.c | 5 +++-- 5 files changed, 13 insertions(+), 9 deletions(-) diff --git a/generator/states-reply.c b/generator/states-reply.c index 5be3431..f0ef47c 100644 ---

Most of the states were calling SET_NEXT_STATE(%.DEAD) then using return -1 on error, to reflect the fact that they had also called set_error() and wanted the caller to notice the failure. Unfortunately, the state machine engine refuses to run the entry code of the next state when the current state returned -1, which meant the DEAD state entry code never runs. A concrete example of the problems

This supersedes the two previous patch series: https://www.redhat.com/archives/libguestfs/2017-March/msg00017.html https://www.redhat.com/archives/libguestfs/2017-March/msg00046.html Rich.

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

Version 3: - Tidies up the code further. - Implements correct handling of SIGTSTP and SIGCONT. - Adds: ^] s - sync filesystems - Adds: ^] z - suspend virt-rescue Rich.

If the server passes us a malformed error reply type with a message length longer than the overall structured reply, we would blindly obey that size and get out of sync with the server (perhaps even hanging on a read for data that will never come). Broken since its introduction in commit 28952eda. Fix it by parsing the tail of an error separate from the message, which also lets us add other