XL: CreateFile/ReadFile should write and read from all disks in parallel. (#1612)

* XL: CreateFile should write to all disks in parallel.

* XL: ReadFile should read from all disks in parallel.

xl-erasure-v1-createfile.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"io"
 	slashpath "path"
+	"sync"
 	"time"
 
 	"github.com/Sirupsen/logrus"
@@ -199,25 +200,35 @@ func (xl XL) writeErasure(volume, path string, reader *io.PipeReader, wcloser *w
 				return
 			}
 
+			var wg = &sync.WaitGroup{}
+			var wErrs = make([]error, len(writers))
 			// Loop through and write encoded data to quorum disks.
 			for index, writer := range writers {
 				if writer == nil {
 					continue
 				}
+				wg.Add(1)
+				go func(index int, writer io.Writer) {
+					defer wg.Done()
 					encodedData := dataBlocks[index]
-				_, err = writers[index].Write(encodedData)
-				if err != nil {
+					_, wErr := writers[index].Write(encodedData)
+					wErrs[index] = wErr
+				}(index, writer)
+			}
+			wg.Wait()
+			for _, wErr := range wErrs {
+				if wErr == nil {
+					continue
+				}
 				log.WithFields(logrus.Fields{
 					"volume": volume,
 					"path":   path,
-						"diskIndex": index,
-					}).Errorf("Writing encoded blocks failed with %s", err)
+				}).Errorf("Writing encoded blocks failed with %s", wErr)
 				// Remove all temp writers upon error.
 				xl.cleanupCreateFileOps(volume, path, append(writers, metadataWriters...)...)
-					reader.CloseWithError(err)
+				reader.CloseWithError(wErr)
 				return
 			}
-			}
 
 			// Update total written.
 			totalSize += int64(n)

xl-erasure-v1-readfile.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"io"
 	slashpath "path"
+	"sync"
 
 	"github.com/Sirupsen/logrus"
 )
@@ -95,6 +96,7 @@ func (xl XL) ReadFile(volume, path string, startOffset int64) (io.ReadCloser, er
 			// Calculate the current encoded block size.
 			curEncBlockSize := getEncodedBlockLen(curBlockSize, metadata.Erasure.DataBlocks)
 			enBlocks := make([][]byte, len(xl.storageDisks))
+			var wg = &sync.WaitGroup{}
 			// Loop through all readers and read.
 			for index, reader := range readers {
 				// Initialize shard slice and fill the data from each parts.
@@ -102,11 +104,19 @@ func (xl XL) ReadFile(volume, path string, startOffset int64) (io.ReadCloser, er
 				if reader == nil {
 					continue
 				}
-				_, err = io.ReadFull(reader, enBlocks[index])
-				if err != nil && err != io.ErrUnexpectedEOF {
+				// Parallelize reading.
+				wg.Add(1)
+				go func(index int, reader io.Reader) {
+					defer wg.Done()
+					// Read the necessary blocks.
+					_, rErr := io.ReadFull(reader, enBlocks[index])
+					if rErr != nil && rErr != io.ErrUnexpectedEOF {
 						readers[index] = nil
 					}
+				}(index, reader)
 			}
+			// Wait for the read routines to finish.
+			wg.Wait()
 
 			// Check blocks if they are all zero in length.
 			if checkBlockSize(enBlocks) == 0 {

xl-objects.go

@@ -109,8 +109,7 @@ func newXLObjects(exportPaths ...string) (ObjectLayer, error) {
 		}
 	}
 
-	// Validate if format exists and input arguments are validated
-	// with backend format.
+	// Validate if format exists and input arguments are validated with backend format.
 	if !isValidFormat(storage, exportPaths...) {
 		return nil, fmt.Errorf("Command-line arguments %s is not valid.", exportPaths)
 	}