search for: nbd_pread_callback

...ue a read command to the NBD server for the range starting at C<offset> and ending at C<offset> + C<count> - 1. NBD can only read all or nothing using this call. The call returns when the data has been read fully into C<buf> or there is an -error. +error. See also C<nbd_pread_callback>, if finer visibility is +required into the server's replies. + +The C<flags> parameter must be C<0> for now (it exists for future NBD +protocol extensions)."; + }; + + "pread_callback", { + default_call with + args = [ BytesOut ("buf", "coun...

...NBD server for the range starting > at C<offset> and ending at C<offset> + C<count> - 1. NBD > can only read all or nothing using this call. The call > returns when the data has been read fully into C<buf> or there is an > -error. > +error. See also C<nbd_pread_callback>, if finer visibility is > +required into the server's replies. > + > +The C<flags> parameter must be C<0> for now (it exists for future NBD > +protocol extensions)."; > + }; > + > + "pread_callback", { > + default_call with > + a...

...aving some sort of callback that gets invoked > on each chunk would allow the client to add in such checking; we could > even provide a utility function in the library to serve as such a > callback if our checking is sufficient for the client's purposes. > Something like: > > nbd_pread_callback(nbd, buf, count, offset, opaque, callback, flags) > > where we still read off the wire into buf (to avoid ping-ponging a read > into a temporary buf that the callback then has to memcpy() into the > real buf), but call the callback as soon as each chunk is received: > > callback...

On Mon, May 27, 2019 at 09:01:01PM -0500, Eric Blake wrote: > diff --git a/lib/rw.c b/lib/rw.c > index feaf468..343c340 100644 > --- a/lib/rw.c > +++ b/lib/rw.c > @@ -234,11 +234,17 @@ int64_t > nbd_unlocked_aio_pread (struct nbd_handle *h, void *buf, > size_t count, uint64_t offset, uint32_t flags) > { > - if (flags != 0) { > + if ((flags

...ent overlapping chunks). But having some sort of callback that gets invoked on each chunk would allow the client to add in such checking; we could even provide a utility function in the library to serve as such a callback if our checking is sufficient for the client's purposes. Something like: nbd_pread_callback(nbd, buf, count, offset, opaque, callback, flags) where we still read off the wire into buf (to avoid ping-ponging a read into a temporary buf that the callback then has to memcpy() into the real buf), but call the callback as soon as each chunk is received: callback(opaque, buf, count, offset, s...

...fs/2019-May/msg00209.html Eric Blake (8): states: Add state for structured reply completion states: Consolidate search for current reply's command pread: Reject server SR read response with no data chunks states: Prepare for read callback states: Wire in a read callback states: Add nbd_pread_callback API states: Add tests for nbd_pread_callback states: Add DF flag support for pread .gitignore | 1 + generator/generator | 140 +++++++++++++++++++-- generator/states-reply-simple.c | 31 +++-- generator/states-reply-structured.c | 147 +++++++++...

On Mon, Jun 17, 2019 at 08:39:43PM -0500, Eric Blake wrote: > Exploration of what it would take to treat the nbd_pread_callback > status parameter as a language-appropriate enum rather than a bare > integer. While I've identified a rough set of the places to change, I > have not actually got it working with Python or OCaml bindings. > --- > > Posting this more for an idea of whether we want to pursue...

...| 32 +- > 7 files changed, 364 insertions(+), 446 deletions(-) > > diff --git a/docs/libnbd.pod b/docs/libnbd.pod > index 5608e63..631bb3b 100644 > --- a/docs/libnbd.pod > +++ b/docs/libnbd.pod > @@ -487,8 +487,7 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call > these functions while processing. > > Callbacks have an opaque C<void *user_data> pointer. This is passed Should we tweak this to explicitly call out "Callbacks in the C language", to differentiate it from bindings to other languages that do n...

...> 7 files changed, 364 insertions(+), 446 deletions(-) > > > > diff --git a/docs/libnbd.pod b/docs/libnbd.pod > > index 5608e63..631bb3b 100644 > > --- a/docs/libnbd.pod > > +++ b/docs/libnbd.pod > > @@ -487,8 +487,7 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call > > these functions while processing. > > > > Callbacks have an opaque C<void *user_data> pointer. This is passed > > Should we tweak this to explicitly call out "Callbacks in the C > language", to differentiate it from binding...

...ents (eg. C<nbd_aio_pread> for equivalent > +starting a command). > > =head2 glib2 integration > > @@ -600,8 +599,8 @@ will use your login name): > =head1 CALLBACKS > > Some libnbd calls take function pointers (eg. > -C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call Eww - we had a bogus link (that should have been nbd_aio_pread_callback). Nice that we fix that as a side effect. > -these functions while processing. > +C<nbd_set_debug_callback>, C<nbd_aio_pread>). Libnbd can call these > +functions while processing....

Exploration of what it would take to treat the nbd_pread_callback status parameter as a language-appropriate enum rather than a bare integer. While I've identified a rough set of the places to change, I have not actually got it working with Python or OCaml bindings. --- Posting this more for an idea of whether we want to pursue it further. I have no hard fe...

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

..._CALLBACK_VALID|LIBNBD_CALLBACK_FREE, meaning it's the > last valid call.) > > > diff --git a/docs/libnbd.pod b/docs/libnbd.pod > index 631bb3b..e9a6030 100644 > --- a/docs/libnbd.pod > +++ b/docs/libnbd.pod > @@ -487,7 +487,59 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call > these functions while processing. > > Callbacks have an opaque C<void *user_data> pointer. This is passed > -as the first parameter to the callback. > +as the second parameter to the callback. > + > +=head2 Callback lifetimes > + > +All...

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

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.

...c | 11 +- tests/oldstyle.c | 10 +- 15 files changed, 233 insertions(+), 168 deletions(-) diff --git a/docs/libnbd.pod b/docs/libnbd.pod index 631bb3b..e9a6030 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -487,7 +487,59 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call these functions while processing. Callbacks have an opaque C<void *user_data> pointer. This is passed -as the first parameter to the callback. +as the second parameter to the callback. + +=head2 Callback lifetimes + +All callbacks have an C<int valid_flag> pa...

...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 calls take function pointers (eg. -C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call -these functions while processing. +C<nbd_set_debug_callback>, C<nbd_aio_pread>). Libnbd can call these +functions while processing. Callbacks have an opaque C<void *user_data> pointer. This is passed as the second parameter to the callback. The opaqu...

...c | 13 +- tests/oldstyle.c | 10 +- 15 files changed, 298 insertions(+), 236 deletions(-) diff --git a/docs/libnbd.pod b/docs/libnbd.pod index 631bb3b..0ce4d32 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -487,7 +487,59 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call these functions while processing. Callbacks have an opaque C<void *user_data> pointer. This is passed -as the first parameter to the callback. +as the second parameter to the callback. + +=head2 Callback lifetimes + +All callbacks have an C<unsigned valid_flag&g...

...| 3 +- lib/rw.c | 32 +- 7 files changed, 364 insertions(+), 446 deletions(-) diff --git a/docs/libnbd.pod b/docs/libnbd.pod index 5608e63..631bb3b 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -487,8 +487,7 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call these functions while processing. Callbacks have an opaque C<void *user_data> pointer. This is passed -as the first parameter to the callback. libnbd functions that take -two callback pointers share the same opaque data for both calls. +as the first parameter to t...

...g /tests/can-zero-flag +/tests/closure-lifetimes /tests/connect-tcp /tests/connect-tls-certs /tests/connect-tls-psk diff --git a/docs/libnbd.pod b/docs/libnbd.pod index 4d31c64..1924305 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -487,7 +487,64 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call these functions while processing. Callbacks have an opaque C<void *user_data> pointer. This is passed -as the first parameter to the callback. +as the second parameter to the callback. The opaque pointer is only +used from the C API, since in other languages you c...