fix file read crash (#6021)

weed/filer/reader_at.go

@@ -199,7 +199,8 @@ func (c *ChunkReadAt) readChunkSliceAt(buffer []byte, chunkView *ChunkView, next
 		return fetchChunkRange(buffer, c.readerCache.lookupFileIdFn, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset))
 	}
 
-	n, err = c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), (uint64(chunkView.ViewOffset)+chunkView.ChunkSize) <= c.readerCache.chunkCache.GetMaxFilePartSizeInCache())
+	shouldCache := (uint64(chunkView.ViewOffset) + chunkView.ChunkSize) <= c.readerCache.chunkCache.GetMaxFilePartSizeInCache()
+	n, err = c.readerCache.ReadChunkAt(buffer, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(chunkView.ChunkSize), shouldCache)
 	if c.lastChunkFid != chunkView.FileId {
 		if chunkView.OffsetInChunk == 0 { // start of a new chunk
 			if c.lastChunkFid != "" {

weed/filer/reader_cache.go

@@ -74,7 +74,8 @@ func (rc *ReaderCache) MaybeCache(chunkViews *Interval[*ChunkView]) {
 
 		// glog.V(4).Infof("prefetch %s offset %d", chunkView.FileId, chunkView.ViewOffset)
 		// cache this chunk if not yet
-		cacher := newSingleChunkCacher(rc, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int(chunkView.ChunkSize), (uint64(chunkView.ViewOffset)+chunkView.ChunkSize) <= rc.chunkCache.GetMaxFilePartSizeInCache())
+		shouldCache := (uint64(chunkView.ViewOffset) + chunkView.ChunkSize) <= rc.chunkCache.GetMaxFilePartSizeInCache()
+		cacher := newSingleChunkCacher(rc, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int(chunkView.ChunkSize), shouldCache)
 		go cacher.startCaching()
 		<-cacher.cacheStartedCh
 		rc.downloaders[chunkView.FileId] = cacher

weed/util/chunk_cache/chunk_cache.go

@@ -42,12 +42,15 @@ func NewTieredChunkCache(maxEntries int64, dir string, diskSizeInUnit int64, uni
 	c.diskCaches[0] = NewOnDiskCacheLayer(dir, "c0_2", diskSizeInUnit*unitSize/8, 2)
 	c.diskCaches[1] = NewOnDiskCacheLayer(dir, "c1_3", diskSizeInUnit*unitSize/4+diskSizeInUnit*unitSize/8, 3)
 	c.diskCaches[2] = NewOnDiskCacheLayer(dir, "c2_2", diskSizeInUnit*unitSize/2, 2)
-	c.maxFilePartSizeInCache = uint64(unitSize*diskSizeInUnit)/4
+	c.maxFilePartSizeInCache = uint64(unitSize*diskSizeInUnit) / 4
 
 	return c
 }
 
 func (c *TieredChunkCache) GetMaxFilePartSizeInCache() (answer uint64) {
+	if c == nil {
+		return 0
+	}
 	return c.maxFilePartSizeInCache
 }