search for: nbd_repli

I ran some local testing on my Fedora 29 system via: $ ./nbdkit memory 1m $ for i in `seq 10`; do ./nbdkit -U - --filter=stats nbd \ statsappend=true statsfile=$file hostname=localhost port=10809 \ --run '~/libnbd/examples/threaded-reads-and-writes $unixsocket' done Pre-patch, the runs averaged 1.266s, 1.30E+08 bits/s Post-patch, the runs averaged 1.154s, 1.42E+08

This one introduces a warning (error because I'm using -Werror): libtool: compile: gcc -DHAVE_CONFIG_H -I. -I../.. -I../../include -I../../src -Wall -Werror -g -O2 -MT nbdkit_nbd_plugin_la-nbd.lo -MD -MP -MF .deps/nbdkit_nbd_plugin_la-nbd.Tpo -c nbd.c -fPIC -DPIC -o .libs/nbdkit_nbd_plugin_la-nbd.o nbd.c: In function ‘nbd_reply’: nbd.c:306:19: error: ‘trans.cookie’ may be used uninitialized

This is a minimal implementation of an NBD forwarder; it lets us convert between old and newstyle connections (great if a client expects one style but the real server only provides the other), or add TLS safety on top of a server without having to rewrite that server. Right now, the real server is expected to live on a named Unix socket with no encryption, and the transactions are serialized

I'm still working on the interleaving (and Rich reminded me on IRC that we still don't have THREAD_MODEL_PARALLEL working anywhere yet, anyways). Since nbdkit doesn't really have a parallel plugin yet, my testing on that front will have to use qemu-nbd as the original server, as well as qemu-io as the driver (qemu-io's aio_read and aio_write commands can be used to trigger

This is a minimal implementation of an NBD forwarder; it lets us convert between old and newstyle connections (great if a client expects one style but the real server only provides the other), or add TLS safety on top of a server without having to rewrite that server. Right now, the real server is expected to live on a named Unix socket, and the transactions are serialized rather than

When we first used libnbd (nbdkit 1.14), it was brand new, so we left in the ability to build a limited nbd plugin without the use of libnbd for comparison. But now that libnbd has had more time under its belt, and we have learned that our nbd-standalone code is not getting much testing, it's time to follow through with our plan to finish off the old code, and now build the nbd plugin only

Tested via: term1$ qemu-nbd -k $PWD/sock -t -f raw -x foo junk --trace=nbd_\* term2$ ./nbdkit -f -v -e bar nbd socket=$PWD/sock export=foo term3$ qemu-io -t none -f raw nbd://localhost:10809/bar --trace=nbd_\* and checking the traces to see that 'w 0 1' vs. 'w -f 0 1' was able to influence whether the FUA flag showed up at the server in term1. Still to go: figure out how to

In preparation for allowing interleaved response, refactor the nbd forwarder so that writes are still done from the thread handling the original request from the client, but all reads are done by a dedicated reader thread. Control between the two flags is gated by a mutex for storing the transaction information, coupled with a pipe for the reader thread to send the final status back to the

Patch 1 played with an early draft of Rich's Fedora 30 libnbd package: https://bugzilla.redhat.com/show_bug.cgi?id=1713767#c17 Note that comment 21 provides a newer package 0.1.1-1 with a different API; and that libnbd has more unreleased API changes in the pipeline (whether that will be called 0.2 or 0.1.2); so we'll have to tweak things based on what is actually available in distros.

libnbd-0.1.2-1 is now available in Fedora 29/30 updates-testing, although it was not compiled against libxml2 so it lacks uri support (I ended up testing patch 4 with a self-built libnbd). Diffs since v1 - rebase to master, bump from libnbd 0.1 to 0.1.2, add URI support, better timing results Still not done - patch 5 needs associated tests Eric Blake (5): nbd: Check for libnbd nbd:

Updated based on other changes that have happened in the meantime: - rely more on cleanup.h (throughout) - split structured read for easier review (patch 2 and 3 were combined in v1) - rely on nbdkit not leaking a server's partial answer (patch 3) - add tests (patch 5) - other bug fixes I found while testing it - drop EOVERFLOW patch for now; it will be separate once upstream NBD protocol

libnbd-0.1.4-1 is now available in Fedora 29/30 updates testing. Diffs since v2 - rebase to master, bump from libnbd 0.1.2 to 0.1.3+, add tests to TLS usage which flushed out the need to turn relative pathnames into absolute, doc tweaks Now that the testsuite covers TLS and libnbd has been fixed to provide the things I found lacking when developing v2, I'm leaning towards pushing this on

I'm hoping to implement .extents for the nbd plugin; this is a prerequisite. I'm not sure about patch 3 - if we like it, I'll squash it to 2, if we don't, I think we are okay just dropping it. I'm also wondering if we have to worry about malicious plugins that don't populate the entire .pread buffer in an effort to get nbdkit to expose portions of the heap; my patch 7 loses

With this, I am finally able to get the nbd plugin to do out-of-order responses to the client. Once this series goes in, we should be ready for Rich to cut a release. Eric Blake (4): nbd: Split reading into separate thread nbd: Protect writes with mutex nbd: Enable parallel handling tests: Test parallel nbd behavior plugins/nbd/nbd.c | 217

The NBD spec was recently patched (nbd.git commit 7827f3ae and friends) to require NBD_OPT_GO for baseline interoperability, with the aim of fewer servers and clients falling back to NBD_OPT_EXPORT_NAME. And since nbdkit as server recently started supporting NBD_OPT_GO (commit f7dd9799), our nbd client as plugin should take advantage of it. This patch is a prerequisite to teaching the nbd plugin

Time to enhance the nbd plugin to request structured replies from the server. For now, deal only with structured reads. The server can now return sparse reads, even though we need nbdkit version 3 before we can in turn return sparse reads back to the client. In general, we have to assume the server is malicious, and so we must sanity check that it sends replies we expect. Thus, we have a choice

I'm still working my way through the filters before this series will be complete, but this is enough of a start to at least get some feedback on the idea of implementing another NBD protocol extension. Eric Blake (9): server: Internal hooks for implementing NBD_CMD_CACHE plugins: Add .cache callback file, split: Implement .cache with posix_fadvise nbd: Implement NBD_CMD_CACHE

A combination of the work that both Rich and I have been doing lately, where filters use only the new API with flags on every command that the client can send over the wire (we can then add support for more flags in nbdkit without having to add new callbacks, as NBD adds more flags upstream). Eric Blake (4): protocol: Split flags from cmd field in requests backend: Pass flags argument through

After more than a month since v2 [1], I've finally got my FUA support series polished. This is all of my outstanding patches, even though some of them were originally posted in separate threads from the original FUA post [2], [3] [1] https://www.redhat.com/archives/libguestfs/2018-January/msg00113.html [2] https://www.redhat.com/archives/libguestfs/2018-January/msg00219.html [3]

Since v1: - rework .can_cache to be tri-state, with default of no advertisement (ripple effect through other patches) - add a lot more patches in order to round out filter support And in the meantime, Rich pushed NBD_CMD_CACHE support into libnbd, so in theory we now have a way to test cache commands through the entire stack. Eric Blake (24): server: Internal hooks for implementing