search for: nbdkit_flag_may_trim

..._can_extents (struct backend *b, struct connection *conn) { @@ -738,7 +750,8 @@ filter_zero (struct backend *b, struct connection *conn, void *handle = connection_get_handle (conn, f->backend.i); struct b_conn nxdata = { .b = f->backend.next, .conn = conn }; - assert (!(flags & ~(NBDKIT_FLAG_MAY_TRIM | NBDKIT_FLAG_FUA))); + assert (!(flags & ~(NBDKIT_FLAG_MAY_TRIM | NBDKIT_FLAG_FUA | + NBDKIT_FLAG_FAST_ZERO))); debug ("%s: zero count=%" PRIu32 " offset=%" PRIu64 " flags=0x%" PRIx32, f->name, count, offset, flags); @@ -818,...

...ct connection *conn, uint32_t count, uint64_t offset, uint32_t flags, int *err) { struct backend_plugin *p = container_of (b, struct backend_plugin, backend); - char *buf; + static const char buf[MAX_REQUEST_SIZE]; uint32_t limit; int r = -1; bool may_trim = flags & NBDKIT_FLAG_MAY_TRIM; @@ -639,12 +639,7 @@ plugin_zero (struct backend *b, struct connection *conn, assert (p->plugin.pwrite || p->plugin._pwrite_old); flags &= ~NBDKIT_FLAG_MAY_TRIM; threadlocal_set_error (0); - limit = count < MAX_REQUEST_SIZE ? count : MAX_REQUEST_SIZE; - buf = calloc (limit,...

...honor the semantics +of C<NBDKIT_FLAG_FAST_ZERO>). =head2 C<.can_extents> @@ -804,15 +832,25 @@ bytes of zeroes at C<offset> in the backing store. This function will not be called if C<.can_zero> returned false. On input, the parameter C<flags> may include C<NBDKIT_FLAG_MAY_TRIM> -unconditionally, and C<NBDKIT_FLAG_FUA> based on the result of -C<.can_fua>. +unconditionally, C<NBDKIT_FLAG_FUA> based on the result of +C<.can_fua>, and C<NBDKIT_FLAG_FAST_ZERO> based on the result of +C<.can_fast_zero>. If C<NBDKIT_FLAG_MAY_TRIM>...

...will ever be passed to a data callback. =item C<.close> @@ -152,6 +173,58 @@ is called once just before the plugin is unloaded from memory. =back +=head1 Flags + +The following flags are defined by nbdkit, and used in various data +serving callbacks as follows: + +=over 4 + +=item C<NBDKIT_FLAG_MAY_TRIM> + +This flag is used by the C<.zero> callback; a plugin may ignore it +without changing valid semantics, so there is no way to disable this +flag. + +=item C<NBDKIT_FLAG_FUA> + +This flag represents Forced Unit Access semantics. It is used by the +C<.pwrite>, C<.zero>,...

...fset) } static int -py_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) +py_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) { PyObject *obj = handle; PyObject *fn; PyObject *args; PyObject *kwargs; PyObject *r; + int may_trim = (flags & NBDKIT_FLAG_MAY_TRIM) != 0; + assert (!(flags & ~NBDKIT_FLAG_MAY_TRIM)); if (callback_defined ("zero", &fn)) { static int zero_may_trim = -1; -- 2.14.3

...void *handle, uint32_t count, uint64_t offset, int may_trim); + void *handle, uint32_t count, uint64_t offset, + uint32_t flags); This intercepts the plugin C<.zero> method and can be used to modify zero requests. +At this time, flags may include C<NBDKIT_FLAG_MAY_TRIM> +unconditionally, and C<NBDKIT_FLAG_FUA> based on the result of +C<.can_flush>. In turn, when calling C<next_ops->zero>, the filter may +pass C<NBDKIT_FLAG_MAY_TRIM> unconditionally, but may only pass +C<NBDKIT_FLAG_FUA> if C<next_ops->can_flush> retur...

...IZE_REQUESTS", > + NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS); > + PyModule_AddIntConstant (m, "THREAD_MODEL_PARALLEL", > + NBDKIT_THREAD_MODEL_PARALLEL); > + > + PyModule_AddIntConstant (m, "FLAG_MAY_TRIM", NBDKIT_FLAG_MAY_TRIM); > + PyModule_AddIntConstant (m, "FLAG_FUA", NBDKIT_FLAG_FUA); > + PyModule_AddIntConstant (m, "FLAG_REQ_ONE", NBDKIT_FLAG_REQ_ONE); > + PyModule_AddIntConstant (m, "FLAG_FAST_ZERO", NBDKIT_FLAG_FAST_ZERO); > + > + PyModule_AddIntConstant (m...

As mentioned in my reviews, I wonder if we should make our python callbacks look a bit more Pythonic by having kwargs added for each new flag that we want to expose. The idea was first floated here: https://www.redhat.com/archives/libguestfs/2018-April/msg00108.html Note that with my proposal, there is no need for a python script to expose a global API_VERSION variable; new flags are added

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

...k is used to write C<count> bytes of zeroes at C<offset> in the backing store. -This function will not be called if C<.can_write> returned false. On +This function will not be called if C<.can_zero> returned false. On input, the parameter C<flags> may include C<NBDKIT_FLAG_MAY_TRIM> unconditionally, and C<NBDKIT_FLAG_FUA> based on the result of C<.can_fua>. @@ -826,6 +845,7 @@ and then users will be able to run it like this: L<nbdkit(1)>, L<nbdkit-filter(3)>, +L<nbdkit-nozero-filter(3)>, L<nbdkit-example1-plugin(1)>, L<nbdkit-e...

...te; + return zeromode != NONE; } static int @@ -81,11 +105,15 @@ nozero_zero (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, uint32_t count, uint64_t offs, uint32_t flags, int *err) { - assert (emulate); + assert (zeromode != NONE); + flags &= ~NBDKIT_FLAG_MAY_TRIM; + + if (zeromode == NOTRIM) + return next_ops->zero (nxdata, count, offs, flags, err); + while (count) { uint32_t size = MIN (count, MAX_WRITE); - if (next_ops->pwrite (nxdata, buffer, size, offs, - flags & ~NBDKIT_FLAG_MAY_TRIM, err) == -1) + i...

...ount, uint64_t offset, uint32_t flags) return -1; } - return 0; + return need_flush ? py_flush (handle, 0) : 0; } static int @@ -556,8 +643,10 @@ py_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) PyObject *kwargs; PyObject *r; int may_trim = (flags & NBDKIT_FLAG_MAY_TRIM) != 0; + int fua = (flags & NBDKIT_FLAG_FUA) != 0; + int need_flush = fua && !zero_has_fua; - assert (!(flags & ~NBDKIT_FLAG_MAY_TRIM)); + assert (!(flags & ~(NBDKIT_FLAG_MAY_TRIM | NBDKIT_FLAG_FUA))); if (callback_defined ("zero", &fn)) { static int z...

...NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS); > > > + PyModule_AddIntConstant (m, "THREAD_MODEL_PARALLEL", > > > + NBDKIT_THREAD_MODEL_PARALLEL); > > > + > > > + PyModule_AddIntConstant (m, "FLAG_MAY_TRIM", NBDKIT_FLAG_MAY_TRIM); > > > + PyModule_AddIntConstant (m, "FLAG_FUA", NBDKIT_FLAG_FUA); > > > + PyModule_AddIntConstant (m, "FLAG_REQ_ONE", NBDKIT_FLAG_REQ_ONE); > > > + PyModule_AddIntConstant (m, "FLAG_FAST_ZERO", NBDKIT_FLAG_FAST_ZERO); > > &...

After more than a month since v2 [1], I've finally got my FUA support series polished. This is all of my outstanding patches, even though some of them were originally posted in separate threads from the original FUA post [2], [3] [1] https://www.redhat.com/archives/libguestfs/2018-January/msg00113.html [2] https://www.redhat.com/archives/libguestfs/2018-January/msg00219.html [3]

Another couple things I noticed that are worth improving, but aren't strictly related to implementing fast zero support. Eric Blake (2): server: Assert sane error responses nozero: More efficient FUA handling filters/nozero/nozero.c | 17 +++++++++++-- server/filters.c | 56 +++++++++++++++++++++++++++++++++-------- server/protocol.c | 32 +++++++++++++++++------ 3 files

...= p->plugin.trim (connection_get_handle (conn), count, offset); + r = p->plugin.trim (connection_get_handle (conn, 0), count, offset); else { errno = EINVAL; return -1; @@ -438,7 +439,7 @@ plugin_zero (struct backend *b, struct connection *conn, int may_trim = (flags & NBDKIT_FLAG_MAY_TRIM) != 0; bool fua = flags & NBDKIT_FLAG_FUA; - assert (connection_get_handle (conn)); + assert (connection_get_handle (conn, 0)); assert (!(flags & ~(NBDKIT_FLAG_MAY_TRIM | NBDKIT_FLAG_FUA))); debug ("zero count=%" PRIu32 " offset=%" PRIu64 " may_trim=%d...

...(r == -1) assert (*err); @@ -343,6 +414,7 @@ backend_zero (struct backend *b, struct connection *conn, uint32_t count, uint64_t offset, uint32_t flags, int *err) { + struct b_conn_handle *h = &conn->handles[b->i]; int r; assert (!(flags & ~(NBDKIT_FLAG_MAY_TRIM | NBDKIT_FLAG_FUA))); @@ -350,6 +422,20 @@ backend_zero (struct backend *b, struct connection *conn, b->name, count, offset, !!(flags & NBDKIT_FLAG_MAY_TRIM), !!(flags & NBDKIT_FLAG_FUA)); + if (writes_blocked (b, conn, "zero", flags)) { + *err = EROFS;...

...yright (C) 2013-2018 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -48,7 +48,16 @@ extern "C" { #define NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS 2 #define NBDKIT_THREAD_MODEL_PARALLEL 3 +#define NBDKIT_FLAG_MAY_TRIM (1<<0) +#define NBDKIT_FLAG_FUA (1<<1) + +/* By default, a plugin gets API version 1; but you may request + * version 2 prior to including this header */ +#ifndef NBDKIT_API_VERSION #define NBDKIT_API_VERSION 1 +#elif (NBDKIT_API_VERS...

...conditions are @@ -102,12 +102,22 @@ nozero_zero (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, uint32_t count, uint64_t offs, uint32_t flags, int *err) { + int writeflags = 0; + bool need_flush = false; + assert (zeromode != NONE); flags &= ~NBDKIT_FLAG_MAY_TRIM; if (zeromode == NOTRIM) return next_ops->zero (nxdata, count, offs, flags, err); + if (flags & NBDKIT_FLAG_FUA) { + if (next_ops->can_fua (nxdata) == NBDKIT_FUA_EMULATE) + need_flush = true; + else + writeflags = NBDKIT_FLAG_FUA; + } + while (count) {...

..."THREAD_MODEL_SERIALIZE_REQUESTS", + NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS); + PyModule_AddIntConstant (m, "THREAD_MODEL_PARALLEL", + NBDKIT_THREAD_MODEL_PARALLEL); + + PyModule_AddIntConstant (m, "FLAG_MAY_TRIM", NBDKIT_FLAG_MAY_TRIM); + PyModule_AddIntConstant (m, "FLAG_FUA", NBDKIT_FLAG_FUA); + PyModule_AddIntConstant (m, "FLAG_REQ_ONE", NBDKIT_FLAG_REQ_ONE); + PyModule_AddIntConstant (m, "FLAG_FAST_ZERO", NBDKIT_FLAG_FAST_ZERO); + + PyModule_AddIntConstant (m, "FUA_NONE",...