diff --git a/fileserver/fileop.go b/fileserver/fileop.go
index b947539..62c5fd4 100644
--- a/fileserver/fileop.go
+++ b/fileserver/fileop.go
@@ -35,6 +35,14 @@ import (
 	"github.com/haiwen/seafile-server/fileserver/repomgr"
 )
 
+const (
+	cacheBlockMapThreshold          = 1 << 23
+	blockMapCacheExpiretime   int64 = 3600 * 24
+	fileopCleaningIntervalSec       = 3600
+)
+
+var blockMapCacheTable sync.Map
+
 // Dirents is an alias for slice of SeafDirent.
 type Dirents []*fsmgr.SeafDirent
 
@@ -49,6 +57,15 @@ func (d Dirents) Len() int {
 	return len(d)
 }
 
+func fileopInit() {
+	ticker := time.NewTicker(time.Second * fileopCleaningIntervalSec)
+	go func() {
+		for range ticker.C {
+			removeFileopExpireCache()
+		}
+	}()
+}
+
 func initUpload() {
 	objDir := filepath.Join(dataDir, "httptemp", "cluster-shared")
 	os.MkdirAll(objDir, os.ModePerm)
@@ -284,6 +301,11 @@ func doFile(rsp http.ResponseWriter, r *http.Request, repo *repomgr.Repo, fileID
 	return nil
 }
 
+type blockMap struct {
+	blkSize    []uint64
+	expireTime int64
+}
+
 func doFileRange(rsp http.ResponseWriter, r *http.Request, repo *repomgr.Repo, fileID string,
 	fileName string, operation string, byteRanges string, user string) *appError {
 
@@ -317,13 +339,32 @@ func doFileRange(rsp http.ResponseWriter, r *http.Request, repo *repomgr.Repo, f
 	rsp.Header().Set("Content-Range", conRange)
 
 	var blkSize []uint64
-	for _, v := range file.BlkIDs {
-		size, err := blockmgr.Stat(repo.StoreID, v)
-		if err != nil {
-			err := fmt.Errorf("failed to stat block %s : %v", v, err)
-			return &appError{err, "", http.StatusInternalServerError}
+	if file.FileSize > cacheBlockMapThreshold {
+		if v, ok := blockMapCacheTable.Load(file.FileID); ok {
+			if blkMap, ok := v.(*blockMap); ok {
+				blkSize = blkMap.blkSize
+			}
+		}
+		if len(blkSize) == 0 {
+			for _, v := range file.BlkIDs {
+				size, err := blockmgr.Stat(repo.StoreID, v)
+				if err != nil {
+					err := fmt.Errorf("failed to stat block %s : %v", v, err)
+					return &appError{err, "", http.StatusInternalServerError}
+				}
+				blkSize = append(blkSize, uint64(size))
+			}
+			blockMapCacheTable.Store(file.FileID, &blockMap{blkSize, time.Now().Unix() + blockMapCacheExpiretime})
+		}
+	} else {
+		for _, v := range file.BlkIDs {
+			size, err := blockmgr.Stat(repo.StoreID, v)
+			if err != nil {
+				err := fmt.Errorf("failed to stat block %s : %v", v, err)
+				return &appError{err, "", http.StatusInternalServerError}
+			}
+			blkSize = append(blkSize, uint64(size))
 		}
-		blkSize = append(blkSize, uint64(size))
 	}
 
 	var off uint64
@@ -3075,3 +3116,16 @@ func indexRawBlocks(repoID string, blockIDs []string, fileHeaders []*multipart.F
 
 	return nil
 }
+
+func removeFileopExpireCache() {
+	deleteBlockMaps := func(key interface{}, value interface{}) bool {
+		if blkMap, ok := value.(*blockMap); ok {
+			if blkMap.expireTime <= time.Now().Unix() {
+				blockMapCacheTable.Delete(key)
+			}
+		}
+		return true
+	}
+
+	blockMapCacheTable.Range(deleteBlockMaps)
+}
diff --git a/fileserver/fileserver.go b/fileserver/fileserver.go
index 3c055b3..d288968 100644
--- a/fileserver/fileserver.go
+++ b/fileserver/fileserver.go
@@ -338,6 +338,8 @@ func main() {
 
 	rpcClientInit()
 
+	fileopInit()
+
 	syncAPIInit()
 
 	sizeSchedulerInit()
diff --git a/fileserver/sync_api.go b/fileserver/sync_api.go
index c65ca54..47c9d76 100644
--- a/fileserver/sync_api.go
+++ b/fileserver/sync_api.go
@@ -35,13 +35,13 @@ const (
 )
 
 const (
-	seafileServerChannelEvent = "seaf_server.event"
-	seafileServerChannelStats = "seaf_server.stats"
-	emptySHA1                 = "0000000000000000000000000000000000000000"
-	tokenExpireTime           = 7200
-	permExpireTime            = 7200
-	virtualRepoExpireTime     = 7200
-	cleaningIntervalSec       = 300
+	seafileServerChannelEvent  = "seaf_server.event"
+	seafileServerChannelStats  = "seaf_server.stats"
+	emptySHA1                  = "0000000000000000000000000000000000000000"
+	tokenExpireTime            = 7200
+	permExpireTime             = 7200
+	virtualRepoExpireTime      = 7200
+	syncAPICleaningIntervalSec = 300
 )
 
 var (
@@ -83,10 +83,10 @@ type statusEventData struct {
 }
 
 func syncAPIInit() {
-	ticker := time.NewTicker(time.Second * cleaningIntervalSec)
+	ticker := time.NewTicker(time.Second * syncAPICleaningIntervalSec)
 	go func() {
 		for range ticker.C {
-			removeExpireCache()
+			removeSyncAPIExpireCache()
 		}
 	}()
 }
@@ -1130,7 +1130,7 @@ func publishRepoEvent(rData *repoEventData) {
 	}
 }
 
-func removeExpireCache() {
+func removeSyncAPIExpireCache() {
 	deleteTokens := func(key interface{}, value interface{}) bool {
 		if info, ok := value.(*tokenInfo); ok {
 			if info.expireTime <= time.Now().Unix() {