+ if clear:
+ # Kernel behavior seems to be that if a file is
+ # referenced, its parents remain referenced too. This
+ # means has_ref() exits early when a collection is not
+ # candidate for eviction.
+ #
+ # By contrast, in_use() doesn't increment references on
+ # parents, so it requires a full tree walk to determine if
+ # a collection is a candidate for eviction. This takes
+ # .07s for 240000 files, which becomes a major drag when
+ # cap_cache is being called several times a second and
+ # there are multiple non-evictable collections in the
+ # cache.
+ #
+ # So it is important for performance that we do the
+ # has_ref() check first.
+
+ if obj.has_ref(True):
+ _logger.debug("InodeCache cannot clear inode %i, still referenced", obj.inode)
+ return
+
+ if obj.in_use():
+ _logger.debug("InodeCache cannot clear inode %i, in use", obj.inode)
+ return
+
+ obj.kernel_invalidate()
+ _logger.debug("InodeCache sent kernel invalidate inode %i", obj.inode)
+ obj.clear()
+
+ # The llfuse lock is released in del_entry(), which is called by
+ # Directory.clear(). While the llfuse lock is released, it can happen
+ # that a reentrant call removes this entry before this call gets to it.
+ # Ensure that the entry is still valid before trying to remove it.
+ if obj.inode not in self._entries:
+ return
+