Filesystem::init return value is ignored

[nrath-js]

As far as I can tell, the set of options returned by a Filesystem's init method is simply thrown away:

https://github.com/cloud-hypervisor/fuse-backend-rs/blob/master/src/api/vfs/sync_io.rs#L55

I can also see this in the debug output for a test filesystem.

2024-11-27T18:00:39.545827Z TRACE fuse: new req Init: InHeader { len: 104, opcode: 26, unique: 2, nodeid: 0x0, uid: 0, gid: 0, pid: 0, padding: 0 }    
2024-11-27T18:00:39.545959Z DEBUG init{_capable=ASYNC_READ | ATOMIC_O_TRUNC | BIG_WRITES | HAS_IOCTL_DIR | AUTO_INVAL_DATA | DO_READDIRPLUS | READDIRPLUS_AUTO | ASYNC_DIO | WRITEBACK_CACHE | PARALLEL_DIROPS | MAX_PAGES | CACHE_SYMLINKS | EXPLICIT_INVAL_DATA | PERFILE_DAX}: enter
2024-11-27T18:00:39.545994Z DEBUG init{_capable=ASYNC_READ | ATOMIC_O_TRUNC | BIG_WRITES | HAS_IOCTL_DIR | AUTO_INVAL_DATA | DO_READDIRPLUS | READDIRPLUS_AUTO | ASYNC_DIO | WRITEBACK_CACHE | PARALLEL_DIROPS | MAX_PAGES | CACHE_SYMLINKS | EXPLICIT_INVAL_DATA | PERFILE_DAX}: return=ASYNC_READ | EXPORT_SUPPORT | ASYNC_DIO | PARALLEL_DIROPS | CACHE_SYMLINKS
2024-11-27T18:00:39.546059Z  INFO FUSE INIT major 7 minor 38
 in_opts: ASYNC_READ | POSIX_LOCKS | ATOMIC_O_TRUNC | EXPORT_SUPPORT | BIG_WRITES | DONT_MASK | SPLICE_WRITE | SPLICE_MOVE | SPLICE_READ | FLOCK_LOCKS | HAS_IOCTL_DIR | AUTO_INVAL_DATA | DO_READDIRPLUS | READDIRPLUS_AUTO | ASYNC_DIO | WRITEBACK_CACHE | ZERO_MESSAGE_OPEN | PARALLEL_DIROPS | HANDLE_KILLPRIV | POSIX_ACL | ABORT_ERROR | MAX_PAGES | CACHE_SYMLINKS | ZERO_MESSAGE_OPENDIR | EXPLICIT_INVAL_DATA | HANDLE_KILLPRIV_V2 | INIT_EXT | PERFILE_DAX
out_opts: ASYNC_READ | ATOMIC_O_TRUNC | BIG_WRITES | HAS_IOCTL_DIR | AUTO_INVAL_DATA | DO_READDIRPLUS | READDIRPLUS_AUTO | ASYNC_DIO | WRITEBACK_CACHE | PARALLEL_DIROPS | MAX_PAGES | CACHE_SYMLINKS | EXPLICIT_INVAL_DATA | PERFILE_DAX    
2024-11-27T18:00:39.546082Z TRACE fuse: new reply OutHeader { len: 80, error: 0, unique: 2 }    

The DEBUG init [...] messages are generated by the test filesystem and indicate input arguments and the return value. Observe how e.g. the DO_READDIRPLUS flag is not included in the output, yet it shows up in out_opts.

Am I missing something?