XL: Bring in support for object versions written during writeQuorum. (#1762)

Erasure is initialized as needed depending on the quorum and onlineDisks.
This way we can manage the quorum at the object layer.

xl-v1-metadata.go

@@ -147,85 +147,6 @@ func (m xlMetaV1) getPartIndexOffset(offset int64) (partIndex int, partOffset in
 	return 0, 0, err
 }
 
-// This function does the following check, suppose
-// object is "a/b/c/d", stat makes sure that objects ""a/b/c""
-// "a/b" and "a" do not exist.
-func (xl xlObjects) parentDirIsObject(bucket, parent string) bool {
-	var isParentDirObject func(string) bool
-	isParentDirObject = func(p string) bool {
-		if p == "." {
-			return false
-		}
-		if xl.isObject(bucket, p) {
-			// If there is already a file at prefix "p" return error.
-			return true
-		}
-		// Check if there is a file as one of the parent paths.
-		return isParentDirObject(path.Dir(p))
-	}
-	return isParentDirObject(parent)
-}
-
-func (xl xlObjects) isObject(bucket, prefix string) bool {
-	// Create errs and volInfo slices of storageDisks size.
-	var errs = make([]error, len(xl.storageDisks))
-
-	// Allocate a new waitgroup.
-	var wg = &sync.WaitGroup{}
-	for index, disk := range xl.storageDisks {
-		wg.Add(1)
-		// Stat file on all the disks in a routine.
-		go func(index int, disk StorageAPI) {
-			defer wg.Done()
-			_, err := disk.StatFile(bucket, path.Join(prefix, xlMetaJSONFile))
-			if err != nil {
-				errs[index] = err
-				return
-			}
-			errs[index] = nil
-		}(index, disk)
-	}
-
-	// Wait for all the Stat operations to finish.
-	wg.Wait()
-
-	var errFileNotFoundCount int
-	for _, err := range errs {
-		if err != nil {
-			if err == errFileNotFound {
-				errFileNotFoundCount++
-				// If we have errors with file not found greater than allowed read
-				// quorum we return err as errFileNotFound.
-				if errFileNotFoundCount > len(xl.storageDisks)-xl.readQuorum {
-					return false
-				}
-				continue
-			}
-			errorIf(err, "Unable to access file "+path.Join(bucket, prefix))
-			return false
-		}
-	}
-	return true
-}
-
-// statPart - stat a part file.
-func (xl xlObjects) statPart(bucket, objectPart string) (fileInfo FileInfo, err error) {
-	// Count for errors encountered.
-	var xlJSONErrCount = 0
-
-	// Return the first success entry based on the selected random disk.
-	for xlJSONErrCount < len(xl.storageDisks) {
-		// Choose a random disk on each attempt, do not hit the same disk all the time.
-		disk := xl.getRandomDisk() // Pick a random disk.
-		fileInfo, err = disk.StatFile(bucket, objectPart)
-		if err == nil {
-			return fileInfo, nil
-		}
-		xlJSONErrCount++ // Update error count.
-	}
-	return FileInfo{}, err
-}
-
 // readXLMetadata - read xl metadata.
 func (xl xlObjects) readXLMetadata(bucket, object string) (xlMeta xlMetaV1, err error) {
 	// Count for errors encountered.
@@ -249,15 +170,6 @@ func (xl xlObjects) readXLMetadata(bucket, object string) (xlMeta xlMetaV1, err
 	return xlMetaV1{}, err
 }
 
-// getDiskDistribution - get disk distribution.
-func (xl xlObjects) getDiskDistribution() []int {
-	var distribution = make([]int, len(xl.storageDisks))
-	for index := range xl.storageDisks {
-		distribution[index] = index + 1
-	}
-	return distribution
-}
-
 // writeXLJson - write `xl.json` on all disks in order.
 func (xl xlObjects) writeXLMetadata(bucket, prefix string, xlMeta xlMetaV1) error {
 	var wg = &sync.WaitGroup{}
@@ -321,3 +233,12 @@ func (xl xlObjects) writeXLMetadata(bucket, prefix string, xlMeta xlMetaV1) erro
 	}
 	return nil
 }
+
+// getDiskDistribution - get disk distribution.
+func (xl xlObjects) getDiskDistribution() []int {
+	var distribution = make([]int, len(xl.storageDisks))
+	for index := range xl.storageDisks {
+		distribution[index] = index + 1
+	}
+	return distribution
+}