rem: LOCK(bc.lock);
add: printf("remove_cached_device_blocks(%d, %d)\n", dev, allow_writes);  LOCK(bc.lock);
context: remove_cached_device_blocks(int dev, int allow_writes){    LOCK(bc.lock);    real_remove_cached_blocks(dev, allow_writes, &bc.normal);    real_remove_cached_blocks(dev, allow_writes, &bc.locked);    max_device_blocks[dev] = 0;    UNLOCK(bc.lock);    return 0;}