search for: libnbd_cmd_flag_fua

...uot;server does not support write operations"); - return -1; - } + if (h->strict & LIBNBD_STRICT_COMMANDS) { + if (nbd_unlocked_is_read_only (h) == 1) { + set_error (EPERM, "server does not support write operations"); + return -1; + } - if ((flags & ~LIBNBD_CMD_FLAG_FUA) != 0) { - set_error (EINVAL, "invalid flag: %" PRIu32, flags); - return -1; - } + if ((flags & ~LIBNBD_CMD_FLAG_FUA) != 0) { + set_error (EINVAL, "invalid flag: %" PRIu32, flags); + return -1; + } - if ((flags & LIBNBD_CMD_FLAG_FUA) != 0 &&a...

...luding zero or more of the +following strictness flags: + +=over 4 + +=item C<LIBNBD_STRICT_COMMANDS> = 1 + +If set, this flag rejects client requests that do not comply with the +set of advertised server flags (for example, attempting a write on +a read-only server, or attempting to use C<LIBNBD_CMD_FLAG_FUA> when +L<nbd_can_fua(3)> returned false). If clear, this flag relies on the +server to reject unexpected commands. + +=back + +For convenience, the constant C<LIBNBD_STRICT_MASK> is available to +describe all strictness flags supported by this build of libnbd. +Future versions of li...

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

...- 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_unlocked_aio_pwrite (struct nbd_handle *h, const void *buf, return -1; } - if ((flags & ~LIBNBD_CMD_FLAG_FUA) != 0) { - set_error (EINVAL, "invalid flag: %" PRIu32, flags); - return -1; - } - if ((flags & LIBNBD_CMD_FLAG_FUA) != 0 && nbd_unlocked_can_fua (h) != 1) { set_error (EINVAL, "server does not support the FUA flag"); @@ -362,11 +343,6 @@ nbd_un...

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

...C<nbd_aio_zero>). Returns false if +the server does not." +^ non_blocking_test_call_description; + }; + "can_df", { default_call with args = []; ret = RBool; @@ -1668,9 +1682,12 @@ The C<flags> parameter may be C<0> for no flags, or may contain C<LIBNBD_CMD_FLAG_FUA> meaning that the server should not return until the data has been committed to permanent storage (if that is supported - some servers cannot do this, see -L<nbd_can_fua(3)>), and/or C<LIBNBD_CMD_FLAG_NO_HOLE> meaning that +L<nbd_can_fua(3)>), C<LIBNBD_CMD_FLAG_NO_HOLE>...

I'm not observing any noticeable performance differences, but I'm liking the diffstat. I can't push this patch until we release a new libnbd version with the _notify API addition, but am posting it now for playing with things. Eric Blake (2): nbd: Move transaction info from heap to stack nbd: Use nbdkit aio_*_notify variants plugins/nbd/nbd.c | 217

libnbd 0.1.7 was released today, which breaks compilation of nbdkit-nbd-plugin. We could work around it by using #ifdef LIBNBD_HAVE_XXX to learn about the renamed functions, but supporting older versions is not all that important when we don't yet have API stability. So patch 1 copes by just bumping the minimum version instead, except that we have yet another pending libnbd patch with an API

...1 lsl 0; "UNIX", 1 lsl 1; @@ -196,6 +202,7 @@ let allow_transport_flags = { } let shutdown_flags = { flag_prefix = "SHUTDOWN"; + guard = None; flags = [ "IMMEDIATE", 1 lsl 1; ] @@ -749,6 +756,22 @@ a read-only server, or attempting to use C<LIBNBD_CMD_FLAG_FUA> when L<nbd_can_fua(3)> returned false). If clear, this flag relies on the server to reject unexpected commands. +=item C<LIBNBD_STRICT_FLAGS> = 2 + +If set, this flag rejects client requests that attempt to set a +command flag not recognized by libnbd (those outside of +C<LIB...

...&s, nbdplug_notify, f)); + nbdplug_notify, &s, f)); return nbdplug_reply (h, &s); } @@ -709,7 +709,7 @@ nbdplug_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) f |= LIBNBD_CMD_FLAG_FUA; nbdplug_prepare (&s); nbdplug_register (h, &s, nbd_aio_zero_callback (h->nbd, count, offset, - &s, nbdplug_notify, f)); + nbdplug_notify, &s, f)); return nbdplug_reply (h,...

...> @@ -196,6 +202,7 @@ let allow_transport_flags = { > } > let shutdown_flags = { > flag_prefix = "SHUTDOWN"; > + guard = None; > flags = [ > "IMMEDIATE", 1 lsl 1; > ] > @@ -749,6 +756,22 @@ a read-only server, or attempting to use C<LIBNBD_CMD_FLAG_FUA> when > L<nbd_can_fua(3)> returned false). If clear, this flag relies on the > server to reject unexpected commands. > > +=item C<LIBNBD_STRICT_FLAGS> = 2 > + > +If set, this flag rejects client requests that attempt to set a > +command flag not recognized by...

...ify (h->nbd, buf, count, offset, + &s, nbdplug_notify, f)); return nbdplug_reply (h, &s); } @@ -751,7 +708,8 @@ nbdplug_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) if (flags & NBDKIT_FLAG_FUA) f |= LIBNBD_CMD_FLAG_FUA; nbdplug_prepare (&s); - nbdplug_register (h, &s, nbd_aio_zero (h->nbd, count, offset, f)); + nbdplug_register (h, &s, nbd_aio_zero_notify (h->nbd, count, offset, + &s, nbdplug_notify, f)); return nbdplug_reply (h, &s)...

...d_aio_pread (h->nbd, buf, count, offset /* , 0 */)); return nbdplug_reply (h, s); } @@ -1253,10 +629,10 @@ nbdplug_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, { struct handle *h = handle; struct transaction *s; + uint32_t f = flags & NBDKIT_FLAG_FUA ? LIBNBD_CMD_FLAG_FUA : 0; assert (!(flags & ~NBDKIT_FLAG_FUA)); - s = nbdplug_request_full (h, flags & NBDKIT_FLAG_FUA ? NBD_CMD_FLAG_FUA : 0, - NBD_CMD_WRITE, offset, count, buf, NULL, NULL); + s = nbdplug_register (h, nbd_aio_pwrite (h->nbd, buf, count, offset, f)); retu...

...(h, nbd_aio_pread (h->nbd, buf, count, offset, 0)); return nbdplug_reply (h, s); } @@ -1258,10 +616,10 @@ nbdplug_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset, { struct handle *h = handle; struct transaction *s; + uint32_t f = flags & NBDKIT_FLAG_FUA ? LIBNBD_CMD_FLAG_FUA : 0; assert (!(flags & ~NBDKIT_FLAG_FUA)); - s = nbdplug_request_full (h, flags & NBDKIT_FLAG_FUA ? NBD_CMD_FLAG_FUA : 0, - NBD_CMD_WRITE, offset, count, buf, NULL, NULL); + s = nbdplug_register (h, nbd_aio_pwrite (h->nbd, buf, count, offset, f)); retu...

...r (h, &s, nbd_aio_pwrite (h->nbd, buf, count, offset, + s.cb, f)); return nbdplug_reply (h, &s); } @@ -729,8 +731,7 @@ nbdplug_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) if (flags & NBDKIT_FLAG_FUA) f |= LIBNBD_CMD_FLAG_FUA; nbdplug_prepare (&s); - nbdplug_register (h, &s, nbd_aio_zero_callback (h->nbd, count, offset, - nbdplug_notify, &s, f)); + nbdplug_register (h, &s, nbd_aio_zero (h->nbd, count, offset, s.cb, f)); return nbdplug_reply (...

This isn't quite finished because not all of the tests or examples have been updated, but it demonstrates an idea: Should we forget about the concept of having multiple connections managed under a single handle? In this patch there is a single ‘struct nbd_handle *’ which manages a single state machine and connection (and therefore no nbd_connection). To connect to a multi-conn server you must

...flags & ~(NBDKIT_FLAG_FUA | NBDKIT_FLAG_MAY_TRIM))); + assert (!(flags & ~(NBDKIT_FLAG_FUA | NBDKIT_FLAG_MAY_TRIM | + NBDKIT_FLAG_FAST_ZERO))); if (!(flags & NBDKIT_FLAG_MAY_TRIM)) f |= LIBNBD_CMD_FLAG_NO_HOLE; if (flags & NBDKIT_FLAG_FUA) f |= LIBNBD_CMD_FLAG_FUA; +#if LIBNBD_HAVE_NBD_CAN_FAST_ZERO + if (flags & NBDKIT_FLAG_FAST_ZERO) + f |= LIBNBD_CMD_FLAG_FAST_ZERO; +#else + assert (!(flags & NBDKIT_FLAG_FAST_ZERO)); +#endif nbdplug_prepare (&s); nbdplug_register (h, &s, nbd_aio_zero (h->nbd, count, offset, s.cb, f)); retu...

This is a cover letter to a series of patches being proposed in tandem to four different projects: - nbd: Document a new NBD_CMD_FLAG_FAST_ZERO command flag - qemu: Implement the flag for both clients and server - libnbd: Implement the flag for clients - nbdkit: Implement the flag for servers, including the nbd passthrough client If you want to test the patches together, I've pushed a

Patch 1 played with an early draft of Rich's Fedora 30 libnbd package: https://bugzilla.redhat.com/show_bug.cgi?id=1713767#c17 Note that comment 21 provides a newer package 0.1.1-1 with a different API; and that libnbd has more unreleased API changes in the pipeline (whether that will be called 0.2 or 0.1.2); so we'll have to tweak things based on what is actually available in distros.

libnbd-0.1.2-1 is now available in Fedora 29/30 updates-testing, although it was not compiled against libxml2 so it lacks uri support (I ended up testing patch 4 with a self-built libnbd). Diffs since v1 - rebase to master, bump from libnbd 0.1 to 0.1.2, add URI support, better timing results Still not done - patch 5 needs associated tests Eric Blake (5): nbd: Check for libnbd nbd: