Don't try to drop inodes on ReleaseDir().

Dropping inodes is expensive (it looks through the entire tree), while
opendir/readdir/releasedir should be cheap.

fuse/fsconnector.go

@@ -144,13 +144,8 @@ func (c *FileSystemConnector) InodeHandleCount() int {
 	return c.inodeMap.Count()
 }
 
-func (c *FileSystemConnector) considerDropInode(node *Inode) {
-	node.treeLock.Lock()
-	c.recursiveConsiderDropInode(node)
-	node.treeLock.Unlock()
-}
-
 // Must hold treeLock.
+
 func (c *FileSystemConnector) recursiveConsiderDropInode(n *Inode) (drop bool) {
 	delChildren := []string{}
 	for k, v := range n.children {

fuse/fsops.go

@@ -298,7 +298,6 @@ func (c *FileSystemConnector) ReleaseDir(header *raw.InHeader, input *raw.Releas
 	node := c.toInode(header.NodeId)
 	opened := node.mount.unregisterFileHandle(input.Fh, node)
 	opened.dir.Release()
-	c.considerDropInode(node)
 }
 
 func (c *FileSystemConnector) GetXAttrSize(header *raw.InHeader, attribute string) (sz int, code Status) {