fs — virtio-fs
fs — virtio-fs
github.com/go-virtio/fs is a pure-Go virtio-fs (FUSE-over-virtio) guest
driver for the standard PCI-bound device (VID 0x1AF4, DID 0x105A — device
type 26). It implements the modern-transport (Virtio 1.0+) init sequence,
the request virtqueue, and the FUSE-over-virtio wire framing. CGO=0, no
architecture-specific assembly, 100% statement test coverage.
Scope
Like blk, this package owns device bring-up, a request
virtqueue, and the on-the-wire request format. For virtio-fs the request
is a FUSE message carried as a descriptor chain (Virtio 1.2 §5.11.6):
readable descriptors : [ struct fuse_in_header | op-specific in-args ]
writable descriptors : [ struct fuse_out_header | op-specific out-args ]The driver exposes a read-write mount closure, each op cited from
Linux include/uapi/linux/fuse.h.
| Side | Ops |
|---|---|
| Read | Init, Lookup, GetAttr, Open, Read, Release, Forget, Destroy |
| Write | OpenRW, Write, Create, Mkdir, Mknod, Symlink, Link, SetAttr, Unlink, Rmdir, Rename, Fsync, Flush |
SetAttr covers truncate (FattrSize), chmod (FattrMode), chown
(FattrUID/FattrGID) and utimes (FattrAtime/FattrMtime) via the
fuse_setattr_in.valid mask. FUSE_WRITE is the only op whose request
is a three-region descriptor chain (readable header + data, writable
reply).
Validated against a real virtiofsd
v0.2.1 fixes a fuse_attr struct-size bug found by real-virtiofsd
validation — the kind of bug a fake-device unit test cannot catch.
License
BSD-3-Clause.