Reimplement run_unaligned_operation over AlignedFile read_vectored_at
and write_vectored_at instead of scattering and gathering through the
per operation write_bytes_at and read_bytes_at closures. The aio and
uring engines already reach this helper for the O_DIRECT misaligned
case, so both now share the same vectored bounce path as the sync
engine and the scatter gather logic lives only in AlignedFile.
The operation iovecs point at the same memory that write_bytes_at and
read_bytes_at reach, and the aligned fast path already hands those
iovecs to the kernel, so the direct vectored call is equivalent. For
guest memory read targets the destination pages are marked dirty by
mark_read_dirty in execute_async before the operation is submitted,
independent of how the bounce copies bytes, so the raw iovec path
preserves dirty tracking. Drop the now unneeded mut bindings at the
call sites.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Filesystems such as tmpfs do not support fallocate with
FALLOC_FL_ZERO_RANGE or FALLOC_FL_PUNCH_HOLE and return EOPNOTSUPP.
When a raw disk image lives on such a filesystem, virtio write zeroes
and discard requests fail with IOERR.
Use the WriteZeroesAt trait from vmm_sys_util through AlignedFile,
which already bundles fallocate with a positional write fallback.
For punch_hole, catch EOPNOTSUPP and fall back to the same trait.
The io_uring engine previously submitted fallocate directly through
the ring, where the async EOPNOTSUPP completion had no retry path.
Route it through the same sync helpers that the other engines
already use.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Remove the worker submodule layer from the raw format directory. The
backend files move up as engine_sync.rs, engine_uring.rs, and
engine_aio.rs, the shared test helpers move up as tests.rs, and the
two alignment helper functions from worker/mod.rs merge into the raw
module.
The vhd backends that reused the raw io_uring and sync engines are
updated to the new block::formats::raw::engine_* paths.
Assisted-by: Claude:Opus-4.8
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
