[RFC PATCH] erofs/zmap.c: Bail out when no further region remains

[Siddh Raman Pant]

On Tue, 15 Nov 2022 08:54:47 +0530, Gao Xiang wrote:
> I just wonder if we should return -EINVAL for post-EOF cases or
> IOMAP_HOLE with arbitrary length?

Since it has been observed that length can be zeroed, and we
must stop, I think we should return an error appropriately.

For a read-only filesystem, we probably don't really need to
care what's after the EOF or in unmapped regions, nothing can
be changed/extended. The definition of IOMAP_HOLE in iomap.h
says it stands for "no blocks allocated, need allocation".

Alternatively, we can return error iff the length of the
extent with holes is zero, like here.

Thanks,
Siddh