search for: nbdkit_extents_foreach

...r handling it > +would look like this: > + > + myfilter_extents (...) > + { > + struct nbdkit_extents_map *map2 = nbdkit_extents_new (); > + next_ops->extents (nxdata, count, offset, flags, map2, err); > + /* transform map2 and return results in extents_map */ > + nbdkit_extents_foreach (map2, transform_offset, extents_map); > + nbdkit_extents_free (map2); > + } And the fact that we can easily call nbdkit_extents_new() as needed means that a filter could, for example, call next_ops->extents() even for its pread implementation (of course, only for a plugin that .can_ext...

I'm not sure which version we're up to now. Anyway I believe this addresses all the points that Eric raised in: https://www.redhat.com/archives/libguestfs/2019-March/msg00038.html https://www.redhat.com/archives/libguestfs/2019-March/msg00040.html In particular: - default state of extents_map is all allocated disk - support hole + non-zero - you can now iterate with bounds -

Second version based on nbdkit_extent* calls, as discussed here: https://www.redhat.com/archives/libguestfs/2019-March/msg00033.html Note in particular there is some subtlety about how filters would work in this implementation. See docs/nbdkit-filter.pod for the details. Rich.

...this: > > + > > + myfilter_extents (...) > > + { > > + struct nbdkit_extents_map *map2 = nbdkit_extents_new (); > > + next_ops->extents (nxdata, count, offset, flags, map2, err); > > + /* transform map2 and return results in extents_map */ > > + nbdkit_extents_foreach (map2, transform_offset, extents_map); > > + nbdkit_extents_free (map2); > > + } > > And the fact that we can easily call nbdkit_extents_new() as needed > means that a filter could, for example, call next_ops->extents() even > for its pread implementation (of course, o...

...passed to the layer below. Without error handling it +would look like this: + + myfilter_extents (...) + { + struct nbdkit_extents_map *map2 = nbdkit_extents_new (); + next_ops->extents (nxdata, count, offset, flags, map2, err); + /* transform map2 and return results in extents_map */ + nbdkit_extents_foreach (map2, transform_offset, extents_map); + nbdkit_extents_free (map2); + } + +If there is an error, C<.extents> should call C<nbdkit_error> with an +error message B<and> return -1 with C<err> set to the positive errno +value to return to the client. + =head1 ERROR HANDLING...

...passed to the layer below. Without error +handling it would look like this: + + myfilter_extents (...) + { + struct nbdkit_extents_map *map2 = nbdkit_extents_new (); + next_ops->extents (nxdata, count, offset, flags, map2, err); + /* transform map2 and return results in extents_map */ + nbdkit_extents_foreach (map2, transform_offset, extents_map); + nbdkit_extents_free (map2); + } + +If there is an error, C<.extents> should call C<nbdkit_error> with an +error message B<and> return -1 with C<err> set to the positive errno +value to return to the client. + +=head3 Allocating and...

I want to post this but mainly for discussion and early review. It's not safe for these patches to all go upstream yet (because not all filters have been checked/adjusted), but if any patches were to go upstream then probably 1 & 2 only are safe. File, VDDK, memory and data plugins all work, although I have only done minimal testing on them. The current tests, such as they are, all

...passed to the layer below. Without error +handling it would look like this: + + myfilter_extents (...) + { + struct nbdkit_extents_map *map2 = nbdkit_extents_new (); + next_ops->extents (nxdata, count, offset, flags, map2, err); + /* transform map2 and return results in extents_map */ + nbdkit_extents_foreach (map2, transform_offset, extents_map, /*..*/); + nbdkit_extents_free (map2); + } + +If there is an error, C<.extents> should call C<nbdkit_error> with an +error message B<and> return -1 with C<err> set to the positive errno +value to return to the client. + +=head3 Allocat...

I think the extents map is just too complicated and is unnecessarily so. How about instead we define the plugin interface to be: int can_extents (void *handle); // as before int extents (void *handle, uint32_t count, uint64_t offset, uint32_t flags, struct nbdkit_extents_list *list); and have the extents_list be a simple list. The first extent you add must start at offset.

...e changed, 4 insertions(+) diff --git a/server/nbdkit.syms b/server/nbdkit.syms index 672abd2..95ef067 100644 --- a/server/nbdkit.syms +++ b/server/nbdkit.syms @@ -42,6 +42,10 @@ nbdkit_absolute_path; nbdkit_debug; nbdkit_error; + nbdkit_extent_add; + nbdkit_extents_free; + nbdkit_extents_foreach; + nbdkit_extents_new; nbdkit_parse_bool; nbdkit_parse_size; nbdkit_read_password; -- 2.20.1

...bdkit_extents_new (); + if (map2 == NULL) + return -1; + if (next_ops->extents (nxdata, count, offs + offset, + flags, map2, err) == -1) { + nbdkit_extents_free (map2); + return -1; + } + + /* Transform offsets in map2, return result in extents_map. */ + if (nbdkit_extents_foreach (map2, subtract_offset, extents_map, + NBDKIT_EXTENTS_FOREACH_FLAG_RANGE, + offset, range) == -1) { + nbdkit_extents_free (map2); + return -1; + } + nbdkit_extents_free (map2); + + return 0; +} + static struct nbdkit_filter filter...

...bdkit_extents_new (); + if (map2 == NULL) + return -1; + if (next_ops->extents (nxdata, count, offs + offset, + flags, map2, err) == -1) { + nbdkit_extents_free (map2); + return -1; + } + + /* Transform offsets in map2, return result in extents_map. */ + if (nbdkit_extents_foreach (map2, subtract_offset, extents_map, + NBDKIT_EXTENTS_FOREACH_FLAG_RANGE, + offset, range) == -1) { + nbdkit_extents_free (map2); + return -1; + } + nbdkit_extents_free (map2); because the plugin was calling: + if (nbdkit_extent...

...struct nbdkit_extents_map *extents_map, + struct block_descriptor **blocks, + size_t *nr_blocks) +{ + const bool req_one = flags & NBD_CMD_FLAG_REQ_ONE; + uint32_t foreach_flags; + struct copy_extents_data data; + + foreach_flags = NBDKIT_EXTENTS_FOREACH_FLAG_RANGE; + if (req_one) + foreach_flags |= NBDKIT_EXTENTS_FOREACH_FLAG_ONE; + + /* Calculate the number of blocks we will be returning. */ + *nr_blocks = 0; + if (nbdkit_extents_foreach (extents_map, + count_extents, nr_blocks, + f...

...over nbdkit_extents_map > + > +One function is provided to filters only to iterate over the extents > +map: > + > + typedef int (*nbdkit_extents_callback) (uint64_t offset, uint64_t length, > + uint32_t type, void *opaque); > + > + int nbdkit_extents_foreach ( > + const struct nbdkit_extents_map *extents_map, > + nbdkit_extents_callback fn, void *opaque, > + uint32_t flags, > + uint64_t range_offset, uint64_t range_length); > + > +=item C<NBDKIT_EXTENTS_FOREACH_FLAG_RANGE> > + >...

...t; + return -1; > + if (next_ops->extents (nxdata, count, offs + offset, > + flags, map2, err) == -1) { > + nbdkit_extents_free (map2); > + return -1; > + } > + > + /* Transform offsets in map2, return result in extents_map. */ > + if (nbdkit_extents_foreach (map2, subtract_offset, extents_map, > + NBDKIT_EXTENTS_FOREACH_FLAG_RANGE, > + offset, range) == -1) { > + nbdkit_extents_free (map2); > + return -1; > + } > + nbdkit_extents_free (map2); > > because the plu...