seaweedfs/weed/mount/filehandle_read.go

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package mount
import (
"context"
"fmt"
"github.com/chrislusf/seaweedfs/weed/filer"
"github.com/chrislusf/seaweedfs/weed/glog"
"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
"io"
)
func (fh *FileHandle) lockForRead(startOffset int64, size int) {
fh.dirtyPages.LockForRead(startOffset, startOffset+int64(size))
}
func (fh *FileHandle) unlockForRead(startOffset int64, size int) {
fh.dirtyPages.UnlockForRead(startOffset, startOffset+int64(size))
}
func (fh *FileHandle) readFromDirtyPages(buff []byte, startOffset int64) (maxStop int64) {
maxStop = fh.dirtyPages.ReadDirtyDataAt(buff, startOffset)
return
}
func (fh *FileHandle) readFromChunks(buff []byte, offset int64) (int64, error) {
fileFullPath := fh.FullPath()
entry := fh.entry
if entry == nil {
return 0, io.EOF
}
if entry.IsInRemoteOnly() {
glog.V(4).Infof("download remote entry %s", fileFullPath)
newEntry, err := fh.downloadRemoteEntry(entry)
if err != nil {
glog.V(1).Infof("download remote entry %s: %v", fileFullPath, err)
return 0, err
}
entry = newEntry
}
fileSize := int64(filer.FileSize(entry))
if fileSize == 0 {
glog.V(1).Infof("empty fh %v", fileFullPath)
return 0, io.EOF
}
if offset+int64(len(buff)) <= int64(len(entry.Content)) {
totalRead := copy(buff, entry.Content[offset:])
glog.V(4).Infof("file handle read cached %s [%d,%d] %d", fileFullPath, offset, offset+int64(totalRead), totalRead)
return int64(totalRead), nil
}
var chunkResolveErr error
if fh.entryViewCache == nil {
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fh.entryViewCache, chunkResolveErr = filer.NonOverlappingVisibleIntervals(fh.wfs.LookupFn(), entry.Chunks, 0, fileSize)
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if chunkResolveErr != nil {
return 0, fmt.Errorf("fail to resolve chunk manifest: %v", chunkResolveErr)
}
fh.reader = nil
}
reader := fh.reader
if reader == nil {
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chunkViews := filer.ViewFromVisibleIntervals(fh.entryViewCache, 0, fileSize)
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glog.V(4).Infof("file handle read %s [%d,%d) from %d views", fileFullPath, offset, offset+int64(len(buff)), len(chunkViews))
for _, chunkView := range chunkViews {
glog.V(4).Infof(" read %s [%d,%d) from chunk %+v", fileFullPath, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size), chunkView.FileId)
}
reader = filer.NewChunkReaderAtFromClient(fh.wfs.LookupFn(), chunkViews, fh.wfs.chunkCache, fileSize)
}
fh.reader = reader
totalRead, err := reader.ReadAt(buff, offset)
if err != nil && err != io.EOF {
glog.Errorf("file handle read %s: %v", fileFullPath, err)
}
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// glog.V(4).Infof("file handle read %s [%d,%d] %d : %v", fileFullPath, offset, offset+int64(totalRead), totalRead, err)
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return int64(totalRead), err
}
func (fh *FileHandle) downloadRemoteEntry(entry *filer_pb.Entry) (*filer_pb.Entry, error) {
fileFullPath := fh.FullPath()
dir, _ := fileFullPath.DirAndName()
err := fh.wfs.WithFilerClient(false, func(client filer_pb.SeaweedFilerClient) error {
request := &filer_pb.CacheRemoteObjectToLocalClusterRequest{
Directory: string(dir),
Name: entry.Name,
}
glog.V(4).Infof("download entry: %v", request)
resp, err := client.CacheRemoteObjectToLocalCluster(context.Background(), request)
if err != nil {
return fmt.Errorf("CacheRemoteObjectToLocalCluster file %s: %v", fileFullPath, err)
}
entry = resp.Entry
fh.wfs.metaCache.InsertEntry(context.Background(), filer.FromPbEntry(request.Directory, resp.Entry))
return nil
})
return entry, err
}