similar to: [nbdkit PATCH 0/2] Another libnbd API bump

I'm not observing any noticeable performance differences, but I'm liking the diffstat. I can't push this patch until we release a new libnbd version with the _notify API addition, but am posting it now for playing with things. Eric Blake (2): nbd: Move transaction info from heap to stack nbd: Use nbdkit aio_*_notify variants plugins/nbd/nbd.c | 217

libnbd 0.1.8 is due out soon, which reorders several function arguments. Signed-off-by: Eric Blake <eblake@redhat.com> --- configure.ac | 4 ++-- plugins/nbd/nbd.c | 17 +++++++++-------- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/configure.ac b/configure.ac index 3b355667..77f08f46 100644 --- a/configure.ac +++ b/configure.ac @@ -718,12 +718,12 @@

--- configure.ac | 4 ++-- plugins/nbd/nbd.c | 12 +++++++++--- README | 2 +- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/configure.ac b/configure.ac index 8c7ee8b..0ce78c7 100644 --- a/configure.ac +++ b/configure.ac @@ -718,12 +718,12 @@ AC_ARG_WITH([libnbd], [], [with_libnbd=check]) AS_IF([test "$with_libnbd" != "no"],[ -

The 0.9.8 release breaks API, requiring a number of changes: - Use symbolic constants instead of magic numbers/open-coded strings (well, the string for "base:allocation" was present before this libnbd bump) - Change callbacks to drop the valid_flag parameter - Add _is to nbd_read_only call - Drop the _callback suffix on nbd_aio_FOO calls - Add a struct for managing callback/user_data

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:

We no longer have to track a linked list of in-flight transactions that are pending resolution, but rely instead on libnbd 0.1.6+ doing it on our behalf. Normally, we will get to call nbdplug_register() prior to the notify callback being reached, but under a heavily-loaded system, it is conceivable that the libnbd state machine can manage to fire off our request and receive a server reply all

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

libnbd 0.1.5 was released today, but is not yet packaged for Fedora. I'd prefer to bump the minimum version in the pkg-config check in configure.ac, as such, I won't be pushing this patch as-is, but waiting until Fedora does have the newer build. But anyone playing with a self-built libnbd library in the meantime needs this patch to deal with the ABI change. --- plugins/nbd/nbd.c | 11

This conversion should be feature compatible with the standalone nbd code. Note that the use of libnbd makes the binary for this particular plugin fall under an LGPLv2+ license rather than BSD; but the source code in nbd.c remains BSD. A lot of code simply disappears, now that I'm no longer directly utilizing the NBD protocol files but relying on libnbd. Coordination between threads from

This conversion should be feature compatible with the standalone nbd code. Note that the use of libnbd makes the binary for this particular plugin fall under an LGPLv2+ license rather than BSD; but the source code in nbd.c remains BSD. A lot of code simply disappears, now that I'm no longer directly utilizing the NBD protocol files but relying on libnbd. Coordination between threads from

When using the nbd_aio_FOO_callback commands, there is nothing further to be learned about the command by calling nbd_aio_command_completed() compared to what the callback already had access to. There are still scenarios where manually retiring the command after the fact is useful (whether the return was 0 to keep the status unchanged, or -1 to alter the retirement status to *error), but by

Another series on top of my exportname filter, marking off another todo bullet point. With this, you can now use the NBD plugin as a transparent passthrough of all export names served by the remote server in both directions (list advertisement server to client, and export name from client to server). Eric Blake (3): nbd: Implement .default_export, .export_description nbd: Add

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

Allow plugins to affect the handling of the new NBD_CMD_FLAG_FAST_ZERO flag, then update affected plugins. In particular, in-memory plugins are always fast; the full plugin is better served by omitting .zero and relying on .pwrite fallback; nbd takes advantage of libnbd extensions proposed in parallel to pass through support; and v2 language bindings expose the choice to their scripts. The

The first four patches are fairly routine clean up and can be reviewed/applied on their own. The fifth patch is problematic as described below. At the moment if you want to proxy through to qemu-nbd (eg. for handling qcow2 files) it's rather complicated and you end up having to manage the sockets and clean up yourself. However the library we use for the proxying supports a perfectly good

It is necessary to kick the state machine any time another thread blocks due to write() encountering a full buffer, to get the reader thread to learn that it must now poll on POLLOUT rather than just POLLIN. POSIX only provides two ways to do this: either poll() on a second fd (our pipe-to-self trick), or interrupt the polling with EINTR due to delivery of a signal. So, I played with the latter

This is a cover letter to a series of patches being proposed in tandem to four different projects: - nbd: Document a new NBD_CMD_FLAG_FAST_ZERO command flag - qemu: Implement the flag for both clients and server - libnbd: Implement the flag for clients - nbdkit: Implement the flag for servers, including the nbd passthrough client If you want to test the patches together, I've pushed a

With new-enough libnbd and our new dynamic-export mode, we can grab the export list from the server for replay to the client. Signed-off-by: Eric Blake <eblake@redhat.com> --- plugins/nbd/nbdkit-nbd-plugin.pod | 7 ++ tests/Makefile.am | 2 + plugins/nbd/nbd.c | 53 ++++++++++ tests/test-nbd-dynamic-content.sh | 2 +- tests/test-nbd-dynamic-list.sh

I fixed the deadlock - turned out to be an actual bug in the nbd plugin (see patch 8). I changed the command syntax so it's now: nbdkit nbd command=qemu arg=-f arg=qcow2 arg=/path/to/disk.qcow2 Nir wrote: 18:08 < nsoffer> rwmjones: regarding the nbd proxy patches, did you have specific flow that help us? 18:08 < nsoffer> rwmjones: or this is just a way to support qcow2 in the