Fix deadlock in conn cleanup (#244)

Calling through to request_free() from clean_req() causes deadlock since
sshfs.lock is already held by the caller of clean_req().

sshfs.c

@@ -1401,9 +1401,11 @@ static int sftp_read(struct conn *conn, uint8_t *type, struct buffer *buf)
 
 static void request_free(struct request *req)
 {
- pthread_mutex_lock(&sshfs.lock);
+ if (req->end_func)
+ req->end_func(req);
+
  req->conn->req_count--;
- pthread_mutex_unlock(&sshfs.lock);
+
  buf_free(&req->reply);
  sem_destroy(&req->ready);
  g_free(req);
@@ -1449,11 +1451,9 @@ static int clean_req(void *key, struct request *req, gpointer user_data)
  req->error = -EIO;
  if (req->want_reply)
  sem_post(&req->ready);
- else {
- if (req->end_func)
- req->end_func(req);
+ else
  request_free(req);
- }
+
  return TRUE;
 }
 
@@ -1515,12 +1515,9 @@ static int process_one_request(struct conn *conn)
  if (req->want_reply)
  sem_post(&req->ready);
  else {
- if (req->end_func) {
- pthread_mutex_lock(&sshfs.lock);
- req->end_func(req);
- pthread_mutex_unlock(&sshfs.lock);
- }
+ pthread_mutex_lock(&sshfs.lock);
  request_free(req);
+ pthread_mutex_unlock(&sshfs.lock);
  }
  } else
  buf_free(&buf);
@@ -1970,12 +1967,9 @@ static int sftp_request_wait(struct request *req, uint8_t type,
  }
 
 out:
- if (req->end_func) {
- pthread_mutex_lock(&sshfs.lock);
- req->end_func(req);
- pthread_mutex_unlock(&sshfs.lock);
- }
+ pthread_mutex_lock(&sshfs.lock);
  request_free(req);
+ pthread_mutex_unlock(&sshfs.lock);
  return err;
 }