search for: libnbd_cmd_flag_df

...all or nothing using this call. The call returns when the data has been read fully into C<buf> or there is an error. See also C<nbd_pread_structured>, if finer visibility is -required into the server's replies. +required into the server's replies, or if you want to use +C<LIBNBD_CMD_FLAG_DF>. The C<flags> parameter must be C<0> for now (it exists for future NBD protocol extensions)."; @@ -1379,8 +1391,11 @@ the server obeyed the requirement that a read call must not have overlapping chunks and must not succeed without enough chunks to cover the entire request....

...is call. The call returns when the data has been read fully into C<buf> or there is an error. -The C<flags> parameter must be C<0> for now (it exists for future NBD -protocol extensions)."; +The C<flags> parameter may be C<0> for no flags, or may contain +C<LIBNBD_CMD_FLAG_DF> meaning that the server should not fragment +a read reply across more than one packet, even if using multiple +packets would otherwise allow a more efficient representation of +holes contained in the region (if that is supported - some servers +cannot do this, see C<nbd_can_df>).";...

...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 & ~LIBNBD_CMD_FLAG_DF) != 0) { > set_error (EINVAL, "invalid flag: %" PRIu32, flags); > return -1; > } > > + if ((flags & LIBNBD_CMD_FLAG_DF) != 0 && > + nbd_unlocked_can_df (h) != 1) { > + set_error (EINVAL, "server does not support the DF flag&quot...

...} } return nbd_internal_command_common (h, 0, NBD_CMD_READ, offset, count, @@ -290,15 +292,17 @@ nbd_unlocked_aio_pread_structured (struct nbd_handle *h, void *buf, struct command_cb cb = { .fn.chunk = chunk, .completion = completion }; - if ((flags & ~LIBNBD_CMD_FLAG_DF) != 0) { - set_error (EINVAL, "invalid flag: %" PRIu32, flags); - return -1; - } + if (h->strict & LIBNBD_STRICT_COMMANDS) { + if ((flags & ~LIBNBD_CMD_FLAG_DF) != 0) { + set_error (EINVAL, "invalid flag: %" PRIu32, flags); + return -1; + } -...

...; --- 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 & ~LIBNBD_CMD_FLAG_DF) != 0) { >> set_error (EINVAL, "invalid flag: %" PRIu32, flags); >> return -1; >> } >> >> + if ((flags & LIBNBD_CMD_FLAG_DF) != 0 && >> + nbd_unlocked_can_df (h) != 1) { >> + set_error (EINVAL, "server does n...

...the libnbd API uses C<uint32_t>; bits outside of the +range permitted by the protocol are always a client-side error. + =back For convenience, the constant C<LIBNBD_STRICT_MASK> is available to @@ -1568,9 +1591,10 @@ required into the server's replies, or if you want to use C<LIBNBD_CMD_FLAG_DF>. The C<flags> parameter must be C<0> for now (it exists for future NBD -protocol extensions)."; +protocol extensions)." +^ strict_call_description; see_also = [Link "aio_pread"; Link "pread_structured"; - Link "get_block_size&...

...EPROTO; + return -1; +} + +static int +read_verify (void *opaque, int64_t handle, int *error) +{ + struct data *data = opaque; + int ret = -1; + + total_reads++; + total_chunks += data->chunks; + if (*error) + goto cleanup; + assert (data->chunks > 0); + if (data->flags & LIBNBD_CMD_FLAG_DF) { + total_df_reads++; + if (data->chunks > 1) { + fprintf (stderr, "buggy server: too many chunks for DF flag\n"); + *error = EPROTO; + goto cleanup; + } + } + if (data->remaining && !*error) { + fprintf (stderr, "buggy server: not enoug...

...alid_flag & LIBNBD_CALLBACK_VALID) { > - struct data *data = opaque; > - > - ret = -1; > - total_reads++; > - total_chunks += data->chunks; > - if (*error) > - goto cleanup; > - assert (data->chunks > 0); > - if (data->flags & LIBNBD_CMD_FLAG_DF) { > - total_df_reads++; > - if (data->chunks > 1) { > - fprintf (stderr, "buggy server: too many chunks for DF flag\n"); > - *error = EPROTO; > - goto cleanup; Pre-existing, but: > - } > - } > - if (data->remain...

We have been inconsistent on how much we reject client-side without even consulting the server, vs. how much we depend on the server to detect failure (even if our request can be deemed undefined per NBD protocol). I'd like to change it so that by default, we reject as much as we can client-side for less traffic, but where the user can also change things on the fly for server-side integration

...t;; bits outside of the > +range permitted by the protocol are always a client-side error. > + > =back > > For convenience, the constant C<LIBNBD_STRICT_MASK> is available to > @@ -1568,9 +1591,10 @@ required into the server's replies, or if you want to use > C<LIBNBD_CMD_FLAG_DF>. > > The C<flags> parameter must be C<0> for now (it exists for future NBD > -protocol extensions)."; > +protocol extensions)." > +^ strict_call_description; > see_also = [Link "aio_pread"; Link "pread_structured"; > -...

RFC because this is an API break, but we haven't declared stable API yet. If we like it, I'm working on using libnbd to implement the nbdkit-nbd plugin; knowing whether it is API version 0.1 or 0.2 will be useful. I also dabbled with allowing optional parameters in python, although my OCaml is weak enough that there may be cleaner ways to approach that. Eric Blake (4): api: Add flags

Since v1: - rebase to applied patches - split out support for Int in callbacks - sort of test that callbacks work in OCaml (see comment in patch 5) - rename API to nbd_pread_structured - expose error as explicit parameter to callback Eric Blake (5): generator: Allow Int in callbacks states: Wire in a read callback states: Add nbd_pread_structured API states: Add tests for

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

...* Repeat with DF flag. */ memset (rbuf, 2, sizeof rbuf); data = (struct data) { .df = true, .count = 1, }; - if (nbd_pread_structured (nbd, rbuf, sizeof rbuf, 2048, &data, read_cb, + if (nbd_pread_structured (nbd, rbuf, sizeof rbuf, 2048, read_cb, &data, LIBNBD_CMD_FLAG_DF) == -1) { fprintf (stderr, "%s\n", nbd_get_error ()); exit (EXIT_FAILURE); @@ -166,7 +166,7 @@ main (int argc, char *argv[]) */ memset (rbuf, 2, sizeof rbuf); data = (struct data) { .count = 2, .fail = true, }; - if (nbd_pread_structured (nbd, rbuf, sizeof rbuf, 2048,...

...NBD_CMD_READ, offset, count, buf, &cb); @@ -304,11 +295,6 @@ nbd_unlocked_aio_pread_structured (struct nbd_handle *h, void *buf, struct command_cb cb = { .fn.chunk = *chunk, .completion = *completion }; - if ((flags & ~LIBNBD_CMD_FLAG_DF) != 0) { - set_error (EINVAL, "invalid flag: %" PRIu32, flags); - return -1; - } - if ((flags & LIBNBD_CMD_FLAG_DF) != 0 && nbd_unlocked_can_df (h) != 1) { set_error (EINVAL, "server does not support the DF flag"); @@ -334,11 +320,6 @@ nbd_unloc...

...t a/lib/rw.c b/lib/rw.c index 95c002c..f49fe25 100644 --- a/lib/rw.c +++ b/lib/rw.c @@ -295,10 +295,12 @@ nbd_unlocked_aio_pread_structured (struct nbd_handle *h, void *buf, struct command_cb cb = { .fn.chunk = *chunk, .completion = *completion }; - if ((flags & LIBNBD_CMD_FLAG_DF) != 0 && - nbd_unlocked_can_df (h) != 1) { - set_error (EINVAL, "server does not support the DF flag"); - return -1; + if (h->strict & LIBNBD_STRICT_COMMANDS) { + if ((flags & LIBNBD_CMD_FLAG_DF) != 0 && + nbd_unlocked_can_df (h) != 1) { +...

...0; - if (valid_flag & LIBNBD_CALLBACK_VALID) { - struct data *data = opaque; + struct data *data = opaque; - ret = -1; - total_reads++; - total_chunks += data->chunks; - if (*error) - goto cleanup; - assert (data->chunks > 0); - if (data->flags & LIBNBD_CMD_FLAG_DF) { - total_df_reads++; - if (data->chunks > 1) { - fprintf (stderr, "buggy server: too many chunks for DF flag\n"); - *error = EPROTO; - goto cleanup; - } - } - if (data->remaining && !*error) { - fprintf (stderr, "buggy...

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

...k *completion, uint32_t flags) { - struct command_cb cb = { .fn.chunk = chunk, - .completion = completion }; + struct command_cb cb = { .fn.chunk = *chunk, + .completion = *completion }; if ((flags & ~LIBNBD_CMD_FLAG_DF) != 0) { set_error (EINVAL, "invalid flag: %" PRIu32, flags); @@ -308,10 +308,10 @@ nbd_unlocked_aio_pread_structured (struct nbd_handle *h, void *buf, int64_t nbd_unlocked_aio_pwrite (struct nbd_handle *h, const void *buf, size_t count, uint64_t offset, -...

...0; + struct data *data = opaque; - if (valid_flag & LIBNBD_CALLBACK_VALID) { - struct data *data = opaque; - - ret = -1; - total_reads++; - total_chunks += data->chunks; - if (*error) - goto cleanup; - assert (data->chunks > 0); - if (data->flags & LIBNBD_CMD_FLAG_DF) { - total_df_reads++; - if (data->chunks > 1) { - fprintf (stderr, "buggy server: too many chunks for DF flag\n"); - *error = EPROTO; - goto cleanup; - } - } - if (data->remaining && !*error) { - fprintf (stderr, "buggy...