Re: [Libguestfs] [PATCH nbdkit v5 FINAL 10/19] offset: Implement mapping of extents.

On 3/28/19 11:18 AM, Richard W.M. Jones wrote: > Allows you to safely use nbdkit-offset-filter on top of a plugin > supporting extents. > --- > filters/offset/offset.c | 36 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 36 insertions(+) > > + > + extents2 = nbdkit_extents_new (offs + offset, real_size - offset); > + if (extents2 == NULL) { > + *err = errno; > + return -1; > + } Here, we are careful to set *err. > + if (next_ops->extents (nxdata, count, offs + offset, > + flags, extents2, err) == -1) > + goto error; And here. > + > + for (i = 0; i < nbdkit_extents_count (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; But here, *err remains unchanged. Is this a problem? Should nbdkit_add_extent() guarantee that errno is sane on failure (right now, it does not)? Affects several filters.