Make DropAll take a []string argument to have selective cache drops.

unionfs/cachingfs.go

@@ -100,7 +100,7 @@ func NewCachingFileSystem(fs fuse.FileSystem, ttlNs int64) *CachingFileSystem {
 
 func (me *CachingFileSystem) DropCache() {
 	for _, c := range []*TimedCache{me.attributes, me.dirs, me.links, me.xattr} {
-		c.DropAll()
+		c.DropAll(nil)
 	}
 }
 

unionfs/timedcache.go

@@ -103,8 +103,15 @@ func (me *TimedCache) RecurringPurge() {
 		func() { me.RecurringPurge() })
 }
 
-func (me *TimedCache) DropAll() {
+func (me *TimedCache) DropAll(names []string) {
 	me.cacheMapMutex.Lock()
 	defer me.cacheMapMutex.Unlock()
-	me.cacheMap = make(map[string]*cacheEntry, len(me.cacheMap))
+
+	if names == nil {
+		me.cacheMap = make(map[string]*cacheEntry, len(me.cacheMap))
+	} else {
+		for _, nm := range names {
+			me.cacheMap[nm] = nil, false
+		}
+	}
 }

unionfs/unionfs.go

@@ -716,10 +716,8 @@ func (me *UnionFs) Rename(src string, dst string) (code fuse.Status) {
 	return code
 }
 
-// TODO - a DropBranchCache which takes a list of names.
-
-func (me *UnionFs) DropBranchCache() {
-	me.branchCache.DropAll()
+func (me *UnionFs) DropBranchCache(names []string) {
+	me.branchCache.DropAll(names)
 }
 
 func (me *UnionFs) DropDeletionCache() {
@@ -743,7 +741,7 @@ func (me *UnionFs) Open(name string, flags uint32) (fuseFile fuse.File, status f
 	if name == _DROP_CACHE {
 		if flags&fuse.O_ANYWRITE != 0 {
 			log.Println("Forced cache drop on", me.Name())
-			me.DropBranchCache()
+			me.DropBranchCache(nil)
 			me.DropDeletionCache()
 			me.DropSubFsCaches()
 		}