similar to: [libnbd PATCH 0/2] Fix docs and testing of completion callback

As promised in my earlier thread on libnbd completion callback question. Eric Blake (2): generator: Refactor handling of closures in unlocked functions generator: Free closures on failure docs/libnbd.pod | 2 +- generator/C.ml | 48 +++++++++++------ generator/C.mli | 1 + lib/debug.c | 7 +-- lib/opt.c | 31 ++++++-----

As proposed here: https://www.redhat.com/archives/libguestfs/2019-August/msg00130.html I didn't actually read Eric's replies to that yet because I've been concentrating on writing these patches all day. Anyway here they are and I'll look at what Eric said about the proposal next. Rich.

Patches 1 & 2 are rather complex, but the end result is that we pass closures + user_data + free function in single struct parameters as I described previously in this email: https://www.redhat.com/archives/libguestfs/2019-August/msg00210.html Patch 3 adds a convenient FREE_CALLBACK macro which seems a worthwhile simplification if you buy into 1 & 2. Patch 4 adds another macro which is

We can easily demonstrate a memory leak when repeatedly calling nbd_aio_pread from nbdsh in the wrong state. True, that isn't something a sane client would normally do, but it's worth fixing. The culprit: when nbd_aio_pread returns a cookie, we guarantee to clean up the closure, but if we fail early and never scheduled the command, nothing ever cleans up the closure. We could document

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 Tue, May 30, 2023 at 04:06:32PM +0200, Laszlo Ersek wrote: > On 5/25/23 15:00, Eric Blake wrote: > > Support sending 64-bit requests if extended headers were negotiated. > > This includes setting NBD_CMD_FLAG_PAYLOAD_LEN any time we send an > > extended NBD_CMD_WRITE; this is such a fundamental part of the > > protocol that for now it is easier to silently ignore

The freeing feature can now be done by associating a free callback with a closure's user_data, so having the valid_flag is no longer necessary and it can be completely removed. This mostly reverts commit 2d9b98e96772e282d51dafac07f16387dadc8afa. --- TODO | 2 - docs/libnbd.pod | 64 ++-------------- examples/glib-main-loop.c |

Change the way that we deal with freeing closures in language bindings: * The valid_flag is removed (mostly reverting commit 2d9b98e96772e282d51dafac07f16387dadc8afa). * An extra ‘free’ parameter is added to all callback structures. This is called by the library whenever the closure won't be called again (so the user_data can be freed). This is analogous to valid_flag ==

This is a subset of my v2 posting, but limited to just the NBD_OPT_LIST handling. The biggest change since v2 is the addition of added unit testing in all four language bindings (C, python, ocaml, golang). The tests require nbdkit built from git on PATH, and may not be entirely idiomatic, but I at least validated that they catch issues (for example, adding an exit statement near the end of the

In v2: ack'ed preliminary patches have been pushed, and I've added a lot of testsuite coverage as well as putting the new API to use in nbdinfo. Eric Blake (2): api: Add nbd_opt_list_meta_context info: List available meta-contexts lib/internal.h | 1 + generator/API.ml | 84 ++++++++-

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

Well, I'm not quite done (I still want to get nbdinfo to work on a single nbd connection for all cases when reading the heads of the file is not required), but I'm happy with patches 1-11, and 12-13 show where I'm headed for getting NBD_OPT_INFO to work. Posting now to see if some of the earlier patches are ready to commit while I continue working on the latter half. Eric Blake (13):

I'm posting this now, as I'm at the end of a workday and I got things working for manual experimentation. Still to do: - write interop tests for qemu-nbd and nbdkit (including my proposed patch addition of qemu-nbd -A to show qemu:allocation-depth) - figure out if we can make 'nbdinfo --map' use the new API to automatically select all contexts advertised by the server Eric Blake

On 8/13/19 5:36 PM, Richard W.M. Jones wrote: > Change the way that we deal with freeing closures in language > bindings: > > * The valid_flag is removed (mostly reverting > commit 2d9b98e96772e282d51dafac07f16387dadc8afa). > > * An extra ‘free’ parameter is added to all callback structures. This > is called by the library whenever the closure won't be called

This continues the changes for adding NBD_OPT_LIST support. Now, instead of libnbd malloc'ing storage itself, the user passes a callback that can handle name/description pairs however it likes, and we get rid of the artificial cap at 10000 exports. However, the user will probably end up malloc'ing a list themselves, as we can't call nbd_set_export_name, or even request NBD_OPT_INFO

This continues the changes for adding NBD_OPT_LIST support. Now, instead of libnbd malloc'ing storage itself, the user passes a callback that can handle name/description pairs however it likes, and we get rid of the artificial cap at 10000 exports. However, the user will probably end up malloc'ing a list themselves, as we can't call nbd_set_export_name, or even request NBD_OPT_INFO

I'm pleased to announce the release of libnbd 1.4.0, a high performance Network Block Device (NBD) client library. Key features of libnbd: * Synchronous API for ease of use. * Asynchronous API for writing non-blocking, multithreaded clients. You can mix both APIs freely. * High performance. * Minimal dependencies for the basic library. * Well-documented, stable API. * Bindings

Let's check for a quite a few more errors. Among other things, this adds some coverage for a few things I've patched recently. --- And these enhancements set me up for my next fix: making NBD_CMD_DISC prevent future commands. tests/errors.c | 167 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 154 insertions(+), 13 deletions(-) diff --git a/tests/errors.c

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

Rich found that I had been using bogus logic, but it was hidden by other bugs in our language bindings until recently. Eric Blake (2): python: Fix test 505 ocaml: Fix test 505 python/t/505-aio-pread-callback.py | 14 +++++++------- .../test_505_aio_pread_structured_callback.ml | 14 +++++++------- 2 files changed, 14 insertions(+), 14 deletions(-) -- 2.20.1