Function fs_create_device 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn fs_create_device(
    path: *const c_char,
    total_blocks: u64,
    block_size: u32,
    initialize: i32,
    master_key: *const u8,
    master_key_len: usize,
) -> *mut FsHandle

Create a filesystem handle backed by a raw block device (e.g. /dev/xvdf).

path: null-terminated path to the block device. total_blocks: number of blocks. Pass 0 to infer from the device size. block_size: block size in bytes. Pass 0 to use the default (65536). initialize: if nonzero, fill the device with random data first (slow on large devices). If zero, open the device as-is. master_key: pointer to the master encryption key bytes. master_key_len: length of master_key in bytes (should be 32).

Returns a pointer to an opaque handle, or null on failure.

Safety

• path must be a valid null-terminated C string.
• master_key must point to master_key_len valid bytes.