rem: return EPERM;
add: Inode *inode = (Inode *)_node;  if (!inode->HasUserAccessableStream()) RETURN_ERROR(B_BAD_VALUE);  ReadLocked locked(inode->Lock()); return file_cache_write_pages(inode->FileCache(), pos, vecs, count, _numBytes);
context: bfs_write_pages(fs_volume _fs, fs_vnode _v, fs_cookie _cookie, off_t pos,	const iovec *vecs, size_t count, size_t *_numBytes){	return EPERM;}