feat: Small object optimization read data in single bulk call (#11207)

cmd/xl-storage.go

@@ -35,7 +35,6 @@ import (
 	"strings"
 	"sync"
 	"sync/atomic"
-	"syscall"
 	"time"
 
 	"github.com/dustin/go-humanize"
@@ -1123,7 +1122,14 @@ func (s *xlStorage) renameLegacyMetadata(volume, path string) error {
 }
 
 // ReadVersion - reads metadata and returns FileInfo at path `xl.meta`
-func (s *xlStorage) ReadVersion(ctx context.Context, volume, path, versionID string) (fi FileInfo, err error) {
+// for all objects less than `128KiB` this call returns data as well
+// along with metadata.
+func (s *xlStorage) ReadVersion(ctx context.Context, volume, path, versionID string, readData bool) (fi FileInfo, err error) {
+	volumeDir, err := s.getVolDir(volume)
+	if err != nil {
+		return fi, err
+	}
+
 	buf, err := s.ReadAll(ctx, volume, pathJoin(path, xlStorageFormatFile))
 	if err != nil {
 		if err == errFileNotFound {
@@ -1158,7 +1164,62 @@ func (s *xlStorage) ReadVersion(ctx context.Context, volume, path, versionID str
 		return fi, errFileNotFound
 	}
 
-	return getFileInfo(buf, volume, path, versionID)
+	fi, err = getFileInfo(buf, volume, path, versionID)
+	if err != nil {
+		return fi, err
+	}
+
+	if readData {
+		// Reading data for small objects when
+		// - object has not yet transitioned
+		// - object size lesser than 32KiB
+		// - object has maximum of 1 parts
+		if fi.TransitionStatus == "" && fi.DataDir != "" && fi.Size < 32*humanize.KiByte && len(fi.Parts) == 1 {
+			fi.Data, err = s.readAllData(volumeDir, pathJoin(volumeDir, path, fi.DataDir, fmt.Sprintf("part.%d", fi.Parts[0].Number)))
+			if err != nil {
+				return fi, err
+			}
+		}
+	}
+
+	return fi, nil
+}
+
+func (s *xlStorage) readAllData(volumeDir, filePath string) (buf []byte, err error) {
+	var file *os.File
+	if globalStorageClass.GetDMA() == storageclass.DMAReadWrite {
+		file, err = disk.OpenFileDirectIO(filePath, os.O_RDONLY, 0666)
+	} else {
+		file, err = os.Open(filePath)
+	}
+	if err != nil {
+		if osIsNotExist(err) {
+			// Check if the object doesn't exist because its bucket
+			// is missing in order to return the correct error.
+			_, err = os.Stat(volumeDir)
+			if err != nil && osIsNotExist(err) {
+				return nil, errVolumeNotFound
+			}
+			return nil, errFileNotFound
+		} else if osIsPermission(err) {
+			return nil, errFileAccessDenied
+		} else if isSysErrNotDir(err) || isSysErrIsDir(err) {
+			return nil, errFileNotFound
+		} else if isSysErrHandleInvalid(err) {
+			// This case is special and needs to be handled for windows.
+			return nil, errFileNotFound
+		} else if isSysErrIO(err) {
+			return nil, errFaultyDisk
+		} else if isSysErrTooManyFiles(err) {
+			return nil, errTooManyOpenFiles
+		} else if isSysErrInvalidArg(err) {
+			return nil, errFileNotFound
+		}
+		return nil, err
+	}
+	defer file.Close()
+
+	return ioutil.ReadAll(file)
 }
 
 // ReadAll reads from r until an error or EOF and returns the data it read.
@@ -1184,7 +1245,6 @@ func (s *xlStorage) ReadAll(ctx context.Context, volume string, path string) (bu
 		return nil, err
 	}
 
-	// Open the file for reading.
 	buf, err = ioutil.ReadFile(filePath)
 	if err != nil {
 		if osIsNotExist(err) {
@@ -1197,7 +1257,7 @@ func (s *xlStorage) ReadAll(ctx context.Context, volume string, path string) (bu
 			return nil, errFileNotFound
 		} else if osIsPermission(err) {
 			return nil, errFileAccessDenied
-		} else if errors.Is(err, syscall.ENOTDIR) || errors.Is(err, syscall.EISDIR) {
+		} else if isSysErrNotDir(err) || isSysErrIsDir(err) {
 			return nil, errFileNotFound
 		} else if isSysErrHandleInvalid(err) {
 			// This case is special and needs to be handled for windows.
@@ -1206,10 +1266,12 @@ func (s *xlStorage) ReadAll(ctx context.Context, volume string, path string) (bu
 			return nil, errFaultyDisk
 		} else if isSysErrTooManyFiles(err) {
 			return nil, errTooManyOpenFiles
+		} else if isSysErrInvalidArg(err) {
+			return nil, errFileNotFound
 		}
-
 		return nil, err
 	}
+
 	return buf, nil
 }
 
@@ -1330,6 +1392,7 @@ func (s *xlStorage) openFile(volume, path string, mode int) (f *os.File, err err
 	if err != nil {
 		return nil, err
 	}
+
 	// Stat a volume entry.
 	_, err = os.Stat(volumeDir)
 	if err != nil {