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

On 3/20/19 5:11 PM, Richard W.M. Jones wrote: > 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(+) If we don't change our minds on the interface in patch 1, then this looks correct. > +/* 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; > + } Ouch - nbdkit_extents_new() returns NULL for 'start >= INT64_MAX' without setting errno. Of course, that failure path should be unreachable here, but if you are going to assign *err based on errno, then we have to make sure patch 1 guarantees sane errno settings on all failure paths.