Add TimedCache.DropAll and CachingFileSystem.DropCache

unionfs/cachingfs.go

@@ -96,6 +96,12 @@ func NewCachingFileSystem(fs fuse.FileSystem, ttlNs int64) *CachingFileSystem {
 	return c
 }
 
+func (me *CachingFileSystem) DropCache() {
+	for _, c := range []*TimedCache{me.attributes, me.dirs, me.links, me.xattr} {
+		c.DropAll()
+	}
+}
+
 func (me *CachingFileSystem) GetAttr(name string) (*os.FileInfo, fuse.Status) {
 	r := me.attributes.Get(name).(*attrResponse)
 	return r.FileInfo, r.Status

unionfs/timedcache.go

@@ -97,3 +97,9 @@ func (me *TimedCache) RecurringPurge() {
 	me.PurgeTimer = time.AfterFunc(5*me.ttlNs,
 		func() { me.RecurringPurge() })
 }
+
+func (me *TimedCache) DropAll() {
+	me.cacheMapMutex.Lock()
+	defer me.cacheMapMutex.Unlock()
+	me.cacheMap = make(map[string]*cacheEntry, len(me.cacheMap))
+}