Mount concurrent read (#4400)

* fix:mount deadlock

* feat: concurrent read

* fix

* Remove useless code

* fix

---------

Co-authored-by: zemul <zhouzemiao@ihuman.com>

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 {

weed/filer/interval_list.go

@@ -27,7 +27,7 @@ func (interval *Interval[T]) Size() int64 {
 type IntervalList[T IntervalValue] struct {
 	head *Interval[T]
 	tail *Interval[T]
-	Lock sync.Mutex
+	Lock sync.RWMutex
 }
 
 func NewIntervalList[T IntervalValue]() *IntervalList[T] {
@@ -248,8 +248,8 @@ func (list *IntervalList[T]) overlayInterval(interval *Interval[T]) {
 }
 
 func (list *IntervalList[T]) Len() int {
-	list.Lock.Lock()
-	defer list.Lock.Unlock()
+	list.Lock.RLock()
+	defer list.Lock.RUnlock()
 
 	var count int
 	for t := list.head; t != nil; t = t.Next {

weed/filer/reader_at.go

@@ -106,8 +106,8 @@ func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) {
 
 	c.readerPattern.MonitorReadAt(offset, len(p))
 
-	c.chunkViews.Lock.Lock()
-	defer c.chunkViews.Lock.Unlock()
+	c.chunkViews.Lock.RLock()
+	defer c.chunkViews.Lock.RUnlock()
 
 	// glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews))
 	n, _, err = c.doReadAt(p, offset)
@@ -118,8 +118,8 @@ func (c *ChunkReadAt) ReadAtWithTime(p []byte, offset int64) (n int, ts int64, e
 
 	c.readerPattern.MonitorReadAt(offset, len(p))
 
-	c.chunkViews.Lock.Lock()
-	defer c.chunkViews.Lock.Unlock()
+	c.chunkViews.Lock.RLock()
+	defer c.chunkViews.Lock.RUnlock()
 
 	// glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews))
 	return c.doReadAt(p, offset)