similar to: [PATCH libnbd v2] examples: Include an example of integrating with glib main loop.

** NOT WORKING ** This patch shows how to integrate libnbd and the glib main loop. Posted mainly as a point of discussion as it doesn't quite work yet. Rich.

On 7/15/19 1:38 PM, Richard W.M. Jones wrote: > --- > .gitignore | 1 + > README | 2 + > configure.ac | 9 + > examples/Makefile.am | 22 ++ > examples/glib-main-loop.c | 501 ++++++++++++++++++++++++++++++++++++++ > 5 files changed, 535 insertions(+) > Rough review (since I've never used a glib main loop

Previously discussed here: https://www.redhat.com/archives/libguestfs/2019-July/msg00213.html It turns out that deferring callbacks is a PITA. (It would be a bit easier if C has closures.) However by rewriting the example we can avoid the need to use the cookie at all and make it run a bit more efficiently, so let's do that instead. Rich.

--- .gitignore | 1 + README | 2 + configure.ac | 9 + examples/Makefile.am | 22 ++ examples/glib-main-loop.c | 511 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 545 insertions(+) diff --git a/.gitignore b/.gitignore index ce02aef..9a8ba37 100644 --- a/.gitignore +++ b/.gitignore @@ -41,6 +41,7 @@ Makefile.in

--- .gitignore | 1 + README | 2 + configure.ac | 9 + examples/Makefile.am | 22 ++ examples/glib-main-loop.c | 501 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 535 insertions(+) diff --git a/.gitignore b/.gitignore index edbf941..79b95b5 100644 --- a/.gitignore +++ b/.gitignore @@ -41,6 +41,7 @@ Makefile.in

On 7/17/19 8:00 AM, Richard W.M. Jones wrote: > --- > .gitignore | 1 + > README | 2 + > configure.ac | 9 + > examples/Makefile.am | 22 ++ > examples/glib-main-loop.c | 511 ++++++++++++++++++++++++++++++++++++++ > 5 files changed, 545 insertions(+) Looks good. > > + revents = g_source_query_unix_fd

There was a theoretic race in this example: If the server was very fast at handling commands then it's possible that in a call such as: cookie = nbd_aio_pread_callback (..., callback, ...); buffers[i].cookie = cookie; nbd_aio_pread_callback finished and calls the callback before returning. buffers[i].cookie would therefore not be set, but the callback() function was checking the list of

I think I've addressed everything that was raised in review. Some of the highlights: - Callbacks should be freed reliably along all exit paths. - There's a simple test of closure lifetimes. - I've tried to use VALID|FREE in all the places where I'm confident that it's safe and correct to do. There may be more places. Note this is an optimization and shouldn't

On 8/13/19 5:36 PM, Richard W.M. Jones wrote: > The definition of functions that take a callback is changed so that > the callback and user_data are combined into a single structure, eg: > > int64_t nbd_aio_pread (struct nbd_handle *h, > void *buf, size_t count, uint64_t offset, > - int (*completion_callback) (/*..*/), void *user_data, > +

v1 was here: https://www.redhat.com/archives/libguestfs/2019-July/thread.html#00231 The changes address everything that Eric picked up in his review of the first two patches. I have also added two more patches (4 and 5) which respectively fix docs and change int status -> unsigned status, as discussed. Passes make, check, check-valgrind. Rich.

> diff --git a/hw/virtio/virtio-pstore.c b/hw/virtio/virtio-pstore.c > new file mode 100644 > index 0000000..b8fb4be > --- /dev/null > +++ b/hw/virtio/virtio-pstore.c > @@ -0,0 +1,699 @@ > +/* > + * Virtio Pstore Device > + * > + * Copyright (C) 2016 LG Electronics > + * > + * Authors: > + * Namhyung Kim <namhyung at gmail.com> > + * > + * This

> diff --git a/hw/virtio/virtio-pstore.c b/hw/virtio/virtio-pstore.c > new file mode 100644 > index 0000000..b8fb4be > --- /dev/null > +++ b/hw/virtio/virtio-pstore.c > @@ -0,0 +1,699 @@ > +/* > + * Virtio Pstore Device > + * > + * Copyright (C) 2016 LG Electronics > + * > + * Authors: > + * Namhyung Kim <namhyung at gmail.com> > + * > + * This

This implements most of what I wrote here: https://www.redhat.com/archives/libguestfs/2019-July/msg00213.html

Natural fallout after my recent testsuite additions that fixed a couple of ocaml bugs in the setters. However, on at least the OCaml code, I'm not sure what we should do if a newer libnbd ever returns a bit that an older NBD.mli was not expecting at the time the OCaml compiler ran (see below). I'm also not sure if there is a more efficient way to avoid outputting Val_FOO() converters for

On 7/17/19 8:40 AM, Eric Blake wrote: > > It may be possible in rare situations that the libnbd state machine can > send() the command AND see data ready to recv() (perhaps from a previous > command still in flight), where it ends up read()ing until blocking and > happens to get the server's reply to this command and fire off the > callback, all prior to the

This applies on top of the OClosure v2 series posted a few minutes ago. Rich.

On Sat, Sep 05, 2020 at 08:40:58PM -0500, Eric Blake wrote: > diff --git a/generator/API.mli b/generator/API.mli > index 712e837..e45b5c0 100644 > --- a/generator/API.mli > +++ b/generator/API.mli > @@ -78,6 +78,8 @@ and ret = > | RString (** return a newly allocated string, > caller frees, NULL for error *) > | RUInt

Still not working, but I took the latest patch and: - rebased it against libnbd 1.0 - fixed it so it handles new args and cbargs The generator now runs without warnings. This patch doesn't handle optargs at all. In C these are converted to non-optional parameter. Rust doesn't (AFAIK) have optional or labelled arguments unfortunately. Rich.

In v2: - now based on my proposal to add LIBNBD_SHUTDOWN_IMMEDIATE - four flags instead of two: STRICT_FLAGS is new (patch 4), and STRICT_BOUNDS is separate from STRICT_ZERO_SIZE (patch 5) - various refactorings for more shared code and less duplication Eric Blake (5): api: Add xxx_MASK constant for each Flags type generator: Refactor filtering of accepted OFlags api: Add

Previously closures had a crude flag which tells if they are persistent or transient. Transient closures (flag = false) last for the lifetime of the currently called libnbd function. Persistent closures had an indefinite lifetime which could last for as long as the handle. In language bindings handling persistent closures was wasteful as we needed to register a "close callback" to