1 files changed, 23 insertions, 7 deletions
diff --git a/weed/filer/filechunk_section.go b/weed/filer/filechunk_section.go
index 11d6e631a..ba591d9ac 100644
--- a/weed/filer/filechunk_section.go
+++ b/weed/filer/filechunk_section.go
@@ -13,7 +13,8 @@ type FileChunkSection struct {
 	visibleIntervals *IntervalList[*VisibleInterval]
 	chunkViews       *IntervalList[*ChunkView]
 	reader           *ChunkReadAt
-	lock             sync.Mutex
+	lock             sync.RWMutex
+	isPrepared       bool
 }
 
 func NewFileChunkSection(si SectionIndex) *FileChunkSection {
@@ -61,6 +62,19 @@ func removeGarbageChunks(section *FileChunkSection, garbageFileIds map[string]st
 }
 
 func (section *FileChunkSection) setupForRead(group *ChunkGroup, fileSize int64) {
+	if section.isPrepared {
+		section.reader.fileSize = fileSize
+		return
+	}
+
+	section.lock.Lock()
+	defer section.lock.Unlock()
+
+	if section.isPrepared {
+		section.reader.fileSize = fileSize
+		return
+	}
+
 	if section.visibleIntervals == nil {
 		section.visibleIntervals = readResolvedChunks(section.chunks, int64(section.sectionIndex)*SectionSize, (int64(section.sectionIndex)+1)*SectionSize)
 		section.chunks, _ = SeparateGarbageChunks(section.visibleIntervals, section.chunks)
@@ -76,23 +90,25 @@ func (section *FileChunkSection) setupForRead(group *ChunkGroup, fileSize int64)
 	if section.reader == nil {
 		section.reader = NewChunkReaderAtFromClient(group.readerCache, section.chunkViews, min(int64(section.sectionIndex+1)*SectionSize, fileSize))
 	}
+
+	section.isPrepared = true
 	section.reader.fileSize = fileSize
 }
 
 func (section *FileChunkSection) readDataAt(group *ChunkGroup, fileSize int64, buff []byte, offset int64) (n int, tsNs int64, err error) {
-	section.lock.Lock()
-	defer section.lock.Unlock()
 
 	section.setupForRead(group, fileSize)
+	section.lock.RLock()
+	defer section.lock.RUnlock()
 
 	return section.reader.ReadAtWithTime(buff, offset)
 }
 
 func (section *FileChunkSection) DataStartOffset(group *ChunkGroup, offset int64, fileSize int64) int64 {
-	section.lock.Lock()
-	defer section.lock.Unlock()
 
 	section.setupForRead(group, fileSize)
+	section.lock.RLock()
+	defer section.lock.RUnlock()
 
 	for x := section.visibleIntervals.Front(); x != nil; x = x.Next {
 		visible := x.Value
@@ -108,10 +124,10 @@ func (section *FileChunkSection) DataStartOffset(group *ChunkGroup, offset int64
 }
 
 func (section *FileChunkSection) NextStopOffset(group *ChunkGroup, offset int64, fileSize int64) int64 {
-	section.lock.Lock()
-	defer section.lock.Unlock()
 
 	section.setupForRead(group, fileSize)
+	section.lock.RLock()
+	defer section.lock.RUnlock()
 
 	isAfterOffset := false
 	for x := section.visibleIntervals.Front(); x != nil; x = x.Next {