refs #5380 don't assert_locked during call to writers(), we may call this when...

refs #5380 don't assert_locked during call to writers(), we may call this when we assume we own the write lock, and therefore don't need the mutex

git-svn-id: file:///svn/toku/tokudb@47043 c7de825b-a66e-492c-adef-691d508d4ae1

ft/cachetable.cc

@@ -2613,10 +2613,10 @@ int toku_cachetable_unpin_and_remove (
     CACHETABLE ct = cachefile->cachetable;
 
     p->dirty = CACHETABLE_CLEAN; // clear the dirty bit.  We're just supposed to remove it.
-    assert(p->value_rwlock.writers());
     // grab disk_nb_mutex to ensure any background thread writing
     // out a cloned value completes
     pair_lock(p);
+    assert(p->value_rwlock.writers());
     nb_mutex_lock(&p->disk_nb_mutex, &p->mutex);
     pair_unlock(p);
     assert(p->cloned_value_data == NULL);

ft/frwlock.cc

@@ -225,7 +225,9 @@ inline uint32_t frwlock::blocked_users(void) const {
     return m_num_want_read + m_num_want_write;
 }
 inline uint32_t frwlock::writers(void) const {
-    toku_mutex_assert_locked(m_mutex);
+    // this is sometimes called as "assert(lock->writers())" when we
+    // assume we have the write lock.  if that's the assumption, we may
+    // not own the mutex, so we don't assert_locked here
     return m_num_writers;
 }
 inline uint32_t frwlock::blocked_writers(void) const {