Introduce DiskBackend with two variants:
- Legacy: wraps Box<dyn async_io::DiskFile> for existing formats
- Next: wraps Box<dyn disk_file::AsyncFullDiskFile>
Methods return BlockResult, with DiskFileError converted up to
BlockError on the Legacy path. The Next path passes through
directly with zero conversion overhead.
This is a transitional type. Once all formats implement
AsyncFullDiskFile, DiskBackend and Legacy are removed and
callers hold Box<dyn AsyncFullDiskFile> directly.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Marker trait combining FullDiskFile and AsyncDiskFile. Blanket impl
covers any type implementing both supertraits.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Marker trait bundling all optional capabilities (PhysicalSize, DiskFd,
SparseCapable, Resizable) on top of DiskFile. Blanket impl covers any
type implementing all constituent traits.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Extend DiskFile with async I/O construction for virtio queue workers.
AsyncDiskFile adds try_clone() for creating independent handles to
the same backing storage, and new_async_io() for constructing an
async I/O engine at the given ring depth.
Bounds: DiskFile + Unpin. Unpin ensures trait objects can be moved
freely (all concrete disk file types are naturally Unpin since they
hold no self referential state).
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Bundles DiskSize and Geometry as the universal disk
capabilities every format must implement. Adds Sync so
that Arc<dyn DiskFile> can be shared across threads for
concurrent readonly access.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Live disk resize support. Single method resize() taking
&mut self and the new size in bytes. Implementations may
return an error if the backend does not support resizing.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Sparse and zero flag support for thin provisioned disk
images. Two methods with false defaults: sparse operations
(punch hole, write zeroes, discard) and zero flag
optimization in WRITE_ZEROES.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Sector and cluster geometry of a disk image. Returns
DiskTopology with a default implementation providing
512B logical and physical block sizes. Formats that
probe the underlying device override this.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Backing file descriptor access for disk images backed by
a file. Returns a BorrowedDiskFd that wraps the raw fd
with lifetime tracking. Not available for network or
memory backed disk formats.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Host allocation size for file-backed disk images. Reports
actual bytes occupied on the host filesystem. Not every
format supports this, e.g. network or memory backed disks.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Reported capacity of a disk image. Every format, be it
file backed, network, memory, exposes a logical size.
Single method logical_size() returning the virtual size
in bytes.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Composable disk capability traits with DiskFile as a supertrait
bundling DiskSize and Geometry. Optional capabilities are
separate traits: PhysicalSize, DiskFd, SparseCapable, Resizable.
AsyncDiskFile extends DiskFile with async I/O construction.
Empty module with doc comment, trait definitions follow.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
