search for: aio_pread_callback

On 8/13/19 5:06 AM, Richard W.M. Jones wrote: > An optional Closure parameter, but otherwise works the same way as > Closure. > @@ -3778,6 +3777,7 @@ let generate_lib_api_c () = > ) args; > List.iter ( > function > + | OClosure { cbname } -> pr ", %s_callback ? \"<fun>\" : \"NULL\"" cbname Well, it also permits a

...al > case for when the user omitted the optional argument and we thus... Yeah I'm not sure about this, plus we don't have any test coverage of it. But it doesn't work ... $ nbdkit null --run './run nbdsh --connect nbd://localhost -c "buf = nbd.Buffer(512)" -c "h.aio_pread_callback (buf, 0)"' Traceback (most recent call last): File "/usr/lib64/python3.7/runpy.py", line 193, in _run_module_as_main "__main__", mod_spec) File "/usr/lib64/python3.7/runpy.py", line 85, in _run_code exec(code, run_globals) File "/home/rjones...

..._aio_* > > (2) Any existing call to nbd_aio_* must have two extra NULL parameters > added before the final flags parameter. > > In non-C languages, only change (1) is required. It is still possible to compile for 0.9.6 and this patch simultaneously, by checking LIBNBD_HAVE_NBD_AIO_PREAD_CALLBACK as a witness of which API style to use (although it's also just as easy to bump minimum version requirements to 0.9.7, once we have a release including this and any other API changes being discussed...). > +++ b/docs/libnbd.pod > @@ -276,9 +276,8 @@ command has completed: > } >...

.../tests/test_590_aio_copy.ml | 5 +-- 4 files changed, 30 insertions(+), 28 deletions(-) diff --git a/generator/generator b/generator/generator index 3add9a4..7f20950 100755 --- a/generator/generator +++ b/generator/generator @@ -1836,9 +1836,8 @@ C<nbd_pread>."; "aio_pread_callback", { default_call with - args = [ BytesPersistOut ("buf", "count"); UInt64 "offset"; - Closure completion_closure ]; - optargs = [ OFlags ("flags", cmd_flags) ]; + args = [ BytesPersistOut ("buf", "count"); UI...

.../tests/test_590_aio_copy.ml | 5 +-- 4 files changed, 30 insertions(+), 28 deletions(-) diff --git a/generator/generator b/generator/generator index 8f15786..6ccfc5f 100755 --- a/generator/generator +++ b/generator/generator @@ -1836,9 +1836,8 @@ C<nbd_pread>."; "aio_pread_callback", { default_call with - args = [ BytesPersistOut ("buf", "count"); UInt64 "offset"; - Closure completion_closure ]; - optargs = [ OFlags ("flags", cmd_flags) ]; + args = [ BytesPersistOut ("buf", "count"); UI...

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

v1 was here: https://www.redhat.com/archives/libguestfs/2019-August/msg00168.html I pushed uncontroversial patches 1-4 v2: - The implementation of OClosure (new patch 1) in Python is fixed. - Patch 2 (old patch 5) is unchanged. - I added a new API for removing debug callbacks. I think this approach has some advantages over using OClosure. - I didn't yet do any work on changing the

...zeof *wrap); wrap->buf = malloc (sizeof (*wrap->buf)); caml_register_generational_global_root (wrap->buf); struct nbd_buffer *buf_buf = NBD_buffer_val (bufv); const void *buf = buf_buf->data; size_t count = buf_buf->len; if (in nbd_aio_pread) { wrap->callback = NULL; res = nbd_aio_pread_callback(h, buf, count, offset, NULL, free_cb, wrap, flags); } else /* in nbd_aio_pread_callback */ { wrap->callback = ...; res = nbd_aio_pread_callback(h, buf, count, offset, completion_cb, free_cb, wrap,...

...change but not significantly). I've run out of time on this patch today because I've got meetings for the rest of the day (and it's only 11am!) However if I did have more time there would be a 7th patch in the series which renames all aio_*_callback functions to simply aio_*. eg. nbd_aio_pread_callback is renamed to nbd_aio_pread (and old nbd_aio_pread is removed). That is obviously a somewhat large albeit it mechanical API change. Rich.

...1a03..aeecaee 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -276,9 +276,8 @@ command has completed: } For almost all high level synchronous calls (eg. C<nbd_pread>) there -are two low level asynchronous equivalents (eg. C<nbd_aio_pread> for -starting a command, and C<nbd_aio_pread_callback> for also registering -a callback to be invoked right before the command is complete). +is a low level asynchronous equivalents (eg. C<nbd_aio_pread> for +starting a command). =head2 glib2 integration @@ -600,8 +599,8 @@ will use your login name): =head1 CALLBACKS Some libnbd call...

...able (Int "error")] } ]; + args = [ UInt64 "count"; UInt64 "offset"; Closure extent_closure ]; optargs = [ OFlags ("flags", cmd_flags) ]; ret = RErr; permitted_states = [ Connected ]; @@ -1820,8 +1836,7 @@ C<nbd_pread>."; "aio_pread_callback", { default_call with args = [ BytesPersistOut ("buf", "count"); UInt64 "offset"; - Closure { cbname="completion"; - cbargs=[CBMutable (Int "error")] } ]; + Closure completion_closure ];...

...ll -returns. - -For these cases you must create a C<NBD.Buffer.t> and ensure that it -is not garbage collected until the command completes. The easiest way -to do this is to use the C<*_callback> variants and free the buffer in -the callback: - - let buf = NBD.Buffer.alloc 512 in - NBD.aio_pread_callback h buf 0_L ( - (* This is called when the command has completed. *) - fun _ -> - NBD.Buffer.free buf; - (* Returning 1 from this callback auto-retires the command. *) - 1 - ) - =head1 EXAMPLES This directory contains examples written in OCaml: diff --git a/ocaml/nbd-c.h b/ocam...

...ll -returns. - -For these cases you must create a C<NBD.Buffer.t> and ensure that it -is not garbage collected until the command completes. The easiest way -to do this is to use the C<*_callback> variants and free the buffer in -the callback: - - let buf = NBD.Buffer.alloc 512 in - NBD.aio_pread_callback h buf 0_L ( - (* This is called when the command has completed. *) - fun _ -> - NBD.Buffer.free buf; - (* Returning 1 from this callback auto-retires the command. *) - 1 - ) - =head1 EXAMPLES This directory contains examples written in OCaml: diff --git a/ocaml/tests/test_590...

On 8/12/19 11:08 AM, Richard W.M. Jones wrote: > This adds a C-only semi-private function for freeing various types of > persistent data passed to libnbd. > > There are some similarities with nbd_add_close_callback which we > removed in commit 7f191b150b52ed50098976309a6af883d245fc56. > --- > +=head1 FREE CALLBACKS > + > +B<Note:> The API described in this

v1 was here: https://www.redhat.com/archives/libguestfs/2019-August/msg00103.html In v2 I've made several changes: - Fix Python callbacks so if they don't return something which is int-like, we assume they mean to return 0. - Add nbd.Buffer free() method. Read commit message in patch 2 to see what this is about. - Fixed the asynch copy test to deal with the unbelievably

...r the entire request. The C<flags> parameter must be C<0> for now (it exists for future NBD protocol extensions)."; @@ -1591,6 +1656,26 @@ C<buf> is valid until the command has completed. Other parameters behave as documented in C<nbd_pread>."; }; + "aio_pread_callback", { + default_call with + args = [ BytesPersistOut ("buf", "count"); UInt64 "offset"; + Opaque "data"; + CallbackPersist ("chunk", [Opaque "data"; + BytesIn ("b...

In this patch series we use the newly introduced free callback on the completion function to dererence the OCaml NBD.Buffer. I will make the same kind of change for Python later in a separate series. The completion function is always called at the C level, even if the OCaml program didn't use the optional argument. That's because the free callback doesn't run otherwise. There is a

...e { cbname="debug_fn"; + args = [ Closure { cbname="debug"; cbargs=[String "context"; String "msg"] } ]; ret = RErr; shortdesc = "set the debug callback"; @@ -1731,7 +1731,7 @@ C<nbd_pread>."; "aio_pread_callback", { default_call with args = [ BytesPersistOut ("buf", "count"); UInt64 "offset"; - Closure { cbname="callback"; + Closure { cbname="completion"; cbargs=[Mutable (Int "error")]...

** INCOMPLETE ** This is the generator change as discussed on the list already. The Python and OCaml bindings are not yet done. It passes all [C only] tests and valgrind. Note that nbd_add_close_callback is inconsistent with other closure types because it passes the user_data parameter after the function. (This is not caused by the current patch, it was already inconsistent). We decided that

This doesn't yet work. However it does make me more convinced than ever that we really need to sort out persistent buffer lifetimes in the library (similar to what we did for closures). Rich.