[Libguestfs] [PATCH nbdkit 4/8] offset: Implement mapping of extents.

Allows you to safely use nbdkit-offset-filter on top of a plugin supporting extents. --- filters/offset/offset.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/filters/offset/offset.c b/filters/offset/offset.c index 058571d..35791bf 100644 --- a/filters/offset/offset.c +++ b/filters/offset/offset.c @@ -37,6 +37,7 @@ #include <stdlib.h> #include <stdint.h> #include <string.h> +#include <assert.h> #include <nbdkit-filter.h> @@ -132,6 +133,39 @@ offset_zero (struct nbdkit_next_ops *next_ops, void *nxdata, return next_ops->zero (nxdata, count, offs + offset, flags, err); } +/* Extents. */ +static int +offset_extents (struct nbdkit_next_ops *next_ops, void *nxdata, + void *handle, uint32_t count, uint64_t offs, uint32_t flags, + struct nbdkit_extents *extents, int *err) +{ + size_t i; + struct nbdkit_extents *extents2; + struct nbdkit_extent e; + + extents2 = nbdkit_extents_new (offs + offset); + if (extents2 == NULL) { + *err = errno; + return -1; + } + if (next_ops->extents (nxdata, count, offs + offset, + flags, extents2, err) == -1) + goto error; + + for (i = 0; i < nbdkit_extents_size (extents2); ++i) { + e = nbdkit_get_extent (extents2, i); + e.offset -= offset; + if (nbdkit_add_extent (extents, e.offset, e.length, e.type) == -1) + goto error; + } + nbdkit_extents_free (extents2); + return 0; + + error: + nbdkit_extents_free (extents2); + return -1; +} + static struct nbdkit_filter filter = { .name = "offset", .longname = "nbdkit offset filter", @@ -144,6 +178,7 @@ static struct nbdkit_filter filter = { .pwrite = offset_pwrite, .trim = offset_trim, .zero = offset_zero, + .extents = offset_extents, }; NBDKIT_REGISTER_FILTER(filter) -- 2.20.1