Merge "libsnapshot:snapuserd: Fix memory leak" am: ef8d3c39

    bool CommitMerge(int num_merge_ops);

    void CloseFds() { cow_fd_ = {}; }

    void FreeResources() { worker_threads_.clear(); }

    size_t GetMetadataAreaSize() { return vec_.size(); }

    void* GetExceptionBuffer(size_t i) { return vec_[i].get(); }

        auto iter = FindHandler(&lock, handler->misc_name());

        if (iter == dm_users_.end()) {

            // RemoveAndJoinHandler() already removed us from the list, and is

            // now waiting on a join(), so just return.

            // now waiting on a join(), so just return. Additionally, release

            // all the resources held by snapuserd object which are shared

            // by worker threads. This should be done when the last reference

            // of "handler" is released; but we will explicitly release here

            // to make sure snapuserd object is freed as it is the biggest

            // consumer of memory in the daemon.

            handler->FreeResources();

            LOG(INFO) << "Exiting handler thread to allow for join: " << misc_name;

            return;

        }

  public:

    explicit DmUserHandler(std::shared_ptr<Snapuserd> snapuserd);

    void FreeResources() { snapuserd_ = nullptr; }

    void FreeResources() {

        // Each worker thread holds a reference to snapuserd.

        // Clear them so that all the resources

        // held by snapuserd is released

        if (snapuserd_) {

            snapuserd_->FreeResources();

            snapuserd_ = nullptr;

        }

    }

    const std::shared_ptr<Snapuserd>& snapuserd() const { return snapuserd_; }

    std::thread& thread() { return thread_; }