refactor objectQuorumFromMeta() to search for parity quorum (#15844)

cmd/erasure-healing-common_test.go

@@ -30,6 +30,53 @@ import (
 	"github.com/minio/madmin-go"
 )
 
+// Returns the latest updated FileInfo files and error in case of failure.
+func getLatestFileInfo(ctx context.Context, partsMetadata []FileInfo, defaultParityCount int, errs []error) (FileInfo, error) {
+	// There should be atleast half correct entries, if not return failure
+	expectedRQuorum := len(partsMetadata) / 2
+	if defaultParityCount == 0 {
+		// if parity count is '0', we expected all entries to be present.
+		expectedRQuorum = len(partsMetadata)
+	}
+
+	reducedErr := reduceReadQuorumErrs(ctx, errs, objectOpIgnoredErrs, expectedRQuorum)
+	if reducedErr != nil {
+		return FileInfo{}, reducedErr
+	}
+
+	// List all the file commit ids from parts metadata.
+	modTimes := listObjectModtimes(partsMetadata, errs)
+
+	// Count all latest updated FileInfo values
+	var count int
+	var latestFileInfo FileInfo
+
+	// Reduce list of UUIDs to a single common value - i.e. the last updated Time
+	modTime := commonTime(modTimes)
+
+	if modTime.IsZero() || modTime.Equal(timeSentinel) {
+		return FileInfo{}, errErasureReadQuorum
+	}
+
+	// Interate through all the modTimes and count the FileInfo(s) with latest time.
+	for index, t := range modTimes {
+		if partsMetadata[index].IsValid() && t.Equal(modTime) {
+			latestFileInfo = partsMetadata[index]
+			count++
+		}
+	}
+
+	if !latestFileInfo.IsValid() {
+		return FileInfo{}, errErasureReadQuorum
+	}
+
+	if count < latestFileInfo.Erasure.DataBlocks {
+		return FileInfo{}, errErasureReadQuorum
+	}
+
+	return latestFileInfo, nil
+}
+
 // validates functionality provided to find most common
 // time occurrence from a list of time.
 func TestCommonTime(t *testing.T) {