quorum calculation getLatestFileInfo should be itself (#13717)

FileInfo quorum shouldn't be passed down, instead
inferred after obtaining a maximally occurring FileInfo.

This PR also changes other functions that rely on
wrong quorum calculation.

Update tests as well to handle the proper requirement. All
these changes are needed when migrating from older deployments
where we used to set N/2 quorum for reads to EC:4 parity in
newer releases.

cmd/erasure-healing-common.go

@@ -134,9 +134,9 @@ func listOnlineDisks(disks []StorageAPI, partsMetadata []FileInfo, errs []error)
 }
 
 // Returns the latest updated FileInfo files and error in case of failure.
-func getLatestFileInfo(ctx context.Context, partsMetadata []FileInfo, errs []error, quorum int) (FileInfo, error) {
+func getLatestFileInfo(ctx context.Context, partsMetadata []FileInfo, errs []error) (FileInfo, error) {
 	// There should be atleast half correct entries, if not return failure
-	reducedErr := reduceReadQuorumErrs(ctx, errs, objectOpIgnoredErrs, quorum)
+	reducedErr := reduceReadQuorumErrs(ctx, errs, objectOpIgnoredErrs, len(partsMetadata)/2)
 	if reducedErr != nil {
 		return FileInfo{}, reducedErr
 	}
@@ -151,6 +151,10 @@ func getLatestFileInfo(ctx context.Context, partsMetadata []FileInfo, errs []err
 	// 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) {
@@ -159,7 +163,11 @@ func getLatestFileInfo(ctx context.Context, partsMetadata []FileInfo, errs []err
 		}
 	}
 
-	if count < quorum {
+	if !latestFileInfo.IsValid() {
+		return FileInfo{}, errErasureReadQuorum
+	}
+
+	if count < latestFileInfo.Erasure.DataBlocks {
 		return FileInfo{}, errErasureReadQuorum
 	}
 
@@ -174,10 +182,8 @@ func getLatestFileInfo(ctx context.Context, partsMetadata []FileInfo, errs []err
 // - slice of errors about the state of data files on disk - can have
 //   a not-found error or a hash-mismatch error.
 func disksWithAllParts(ctx context.Context, onlineDisks []StorageAPI, partsMetadata []FileInfo,
-	errs []error, bucket, object string, scanMode madmin.HealScanMode) ([]StorageAPI, []error) {
-
-	// List of disks having latest version of the object xl.meta (by modtime)
-	_, modTime := listOnlineDisks(onlineDisks, partsMetadata, errs)
+	errs []error, latestMeta FileInfo,
+	bucket, object string, scanMode madmin.HealScanMode) ([]StorageAPI, []error) {
 
 	availableDisks := make([]StorageAPI, len(onlineDisks))
 	dataErrs := make([]error, len(onlineDisks))
@@ -214,13 +220,13 @@ func disksWithAllParts(ctx context.Context, onlineDisks []StorageAPI, partsMetad
 			dataErrs[i] = errs[i]
 			continue
 		}
-		if onlineDisk == nil {
+		if onlineDisk == OfflineDisk {
 			dataErrs[i] = errDiskNotFound
 			continue
 		}
 
 		meta := partsMetadata[i]
-		if !meta.ModTime.Equal(modTime) {
+		if !meta.ModTime.Equal(latestMeta.ModTime) || meta.DataDir != latestMeta.DataDir {
 			dataErrs[i] = errFileCorrupt
 			partsMetadata[i] = FileInfo{}
 			continue
@@ -268,17 +274,18 @@ func disksWithAllParts(ctx context.Context, onlineDisks []StorageAPI, partsMetad
 			continue
 		}
 
+		meta.DataDir = latestMeta.DataDir
 		switch scanMode {
 		case madmin.HealDeepScan:
 			// disk has a valid xl.meta but may not have all the
 			// parts. This is considered an outdated disk, since
 			// it needs healing too.
-			if !partsMetadata[i].Deleted && !partsMetadata[i].IsRemote() {
-				dataErrs[i] = onlineDisk.VerifyFile(ctx, bucket, object, partsMetadata[i])
+			if !meta.Deleted && !meta.IsRemote() {
+				dataErrs[i] = onlineDisk.VerifyFile(ctx, bucket, object, meta)
 			}
 		case madmin.HealNormalScan:
-			if !partsMetadata[i].Deleted && !partsMetadata[i].IsRemote() {
-				dataErrs[i] = onlineDisk.CheckParts(ctx, bucket, object, partsMetadata[i])
+			if !meta.Deleted && !meta.IsRemote() {
+				dataErrs[i] = onlineDisk.CheckParts(ctx, bucket, object, meta)
 			}
 		}
 

cmd/erasure-healing-common_test.go

@@ -20,6 +20,7 @@ package cmd
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -193,7 +194,7 @@ func TestListOnlineDisks(t *testing.T) {
 			}
 
 			partsMetadata, errs := readAllFileInfo(ctx, erasureDisks, bucket, object, "", false)
-			fi, err := getLatestFileInfo(ctx, partsMetadata, errs, getReadQuorum(len(disks)))
+			fi, err := getLatestFileInfo(ctx, partsMetadata, errs)
 			if err != nil {
 				t.Fatalf("Failed to getLatestFileInfo %v", err)
 			}
@@ -250,7 +251,7 @@ func TestListOnlineDisks(t *testing.T) {
 				t.Fatalf("Expected modTime to be equal to %v but was found to be %v",
 					test.expectedTime, modTime)
 			}
-			availableDisks, newErrs := disksWithAllParts(ctx, onlineDisks, partsMetadata, test.errs, bucket, object, madmin.HealDeepScan)
+			availableDisks, newErrs := disksWithAllParts(ctx, onlineDisks, partsMetadata, test.errs, fi, bucket, object, madmin.HealDeepScan)
 			test.errs = newErrs
 
 			if test._tamperBackend != noTamper {
@@ -365,7 +366,7 @@ func TestListOnlineDisksSmallObjects(t *testing.T) {
 			}
 
 			partsMetadata, errs := readAllFileInfo(ctx, erasureDisks, bucket, object, "", true)
-			_, err = getLatestFileInfo(ctx, partsMetadata, errs, getReadQuorum(len(disks)))
+			_, err = getLatestFileInfo(ctx, partsMetadata, errs)
 			if err != nil {
 				t.Fatalf("Failed to getLatestFileInfo %v", err)
 			}
@@ -421,9 +422,9 @@ func TestListOnlineDisksSmallObjects(t *testing.T) {
 
 			}
 			partsMetadata, errs = readAllFileInfo(ctx, erasureDisks, bucket, object, "", true)
-			_, err = getLatestFileInfo(ctx, partsMetadata, errs, len(disks)/2)
-			if err != nil {
-				t.Fatalf("Failed to getLatestFileInfo %v", err)
+			fi, err := getLatestFileInfo(ctx, partsMetadata, errs)
+			if !errors.Is(err, errErasureReadQuorum) {
+				t.Fatalf("Failed to getLatestFileInfo, expected %v, got %v", errErasureReadQuorum, err)
 			}
 
 			onlineDisks, modTime := listOnlineDisks(erasureDisks, partsMetadata, test.errs)
@@ -432,7 +433,7 @@ func TestListOnlineDisksSmallObjects(t *testing.T) {
 					test.expectedTime, modTime)
 			}
 
-			availableDisks, newErrs := disksWithAllParts(ctx, onlineDisks, partsMetadata, test.errs, bucket, object, madmin.HealDeepScan)
+			availableDisks, newErrs := disksWithAllParts(ctx, onlineDisks, partsMetadata, test.errs, fi, bucket, object, madmin.HealDeepScan)
 			test.errs = newErrs
 
 			if test._tamperBackend != noTamper {
@@ -486,9 +487,14 @@ func TestDisksWithAllParts(t *testing.T) {
 		t.Fatalf("Failed to read xl meta data %v", err)
 	}
 
+	fi, err := getLatestFileInfo(ctx, partsMetadata, errs)
+	if err != nil {
+		t.Fatalf("Failed to get quorum consistent fileInfo %v", err)
+	}
+
 	erasureDisks, _ = listOnlineDisks(erasureDisks, partsMetadata, errs)
 
-	filteredDisks, errs := disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, bucket, object, madmin.HealDeepScan)
+	filteredDisks, errs := disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, fi, bucket, object, madmin.HealDeepScan)
 
 	if len(filteredDisks) != len(erasureDisks) {
 		t.Errorf("Unexpected number of disks: %d", len(filteredDisks))
@@ -509,7 +515,7 @@ func TestDisksWithAllParts(t *testing.T) {
 	partsMetadata[0].ModTime = partsMetadata[0].ModTime.Add(-1 * time.Hour)
 
 	errs = make([]error, len(erasureDisks))
-	filteredDisks, _ = disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, bucket, object, madmin.HealDeepScan)
+	filteredDisks, _ = disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, fi, bucket, object, madmin.HealDeepScan)
 
 	if len(filteredDisks) != len(erasureDisks) {
 		t.Errorf("Unexpected number of disks: %d", len(filteredDisks))
@@ -529,7 +535,7 @@ func TestDisksWithAllParts(t *testing.T) {
 	partsMetadata[1].DataDir = "foo-random"
 
 	errs = make([]error, len(erasureDisks))
-	filteredDisks, _ = disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, bucket, object, madmin.HealDeepScan)
+	filteredDisks, _ = disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, fi, bucket, object, madmin.HealDeepScan)
 
 	if len(filteredDisks) != len(erasureDisks) {
 		t.Errorf("Unexpected number of disks: %d", len(filteredDisks))
@@ -565,7 +571,7 @@ func TestDisksWithAllParts(t *testing.T) {
 	}
 
 	errs = make([]error, len(erasureDisks))
-	filteredDisks, errs = disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, bucket, object, madmin.HealDeepScan)
+	filteredDisks, errs = disksWithAllParts(ctx, erasureDisks, partsMetadata, errs, fi, bucket, object, madmin.HealDeepScan)
 
 	if len(filteredDisks) != len(erasureDisks) {
 		t.Errorf("Unexpected number of disks: %d", len(filteredDisks))

cmd/erasure-healing.go

@@ -288,13 +288,20 @@ func (er erasureObjects) healObject(ctx context.Context, bucket string, object s
 	// Re-read when we have lock...
 	partsMetadata, errs := readAllFileInfo(ctx, storageDisks, bucket, object, versionID, true)
 
-	if _, err = getLatestFileInfo(ctx, partsMetadata, errs, er.defaultParityCount); err != nil {
+	if _, err = getLatestFileInfo(ctx, partsMetadata, errs); err != nil {
 		return er.purgeObjectDangling(ctx, bucket, object, versionID, partsMetadata, errs, []error{}, opts)
 	}
 
 	// List of disks having latest version of the object er.meta
 	// (by modtime).
-	_, modTime := listOnlineDisks(storageDisks, partsMetadata, errs)
+	onlineDisks, modTime := listOnlineDisks(storageDisks, partsMetadata, errs)
+
+	// Latest FileInfo for reference. If a valid metadata is not
+	// present, it is as good as object not found.
+	latestMeta, err := pickValidFileInfo(ctx, partsMetadata, modTime, result.DataBlocks)
+	if err != nil {
+		return result, toObjectErr(err, bucket, object, versionID)
+	}
 
 	// List of disks having all parts as per latest metadata.
 	// NOTE: do not pass in latestDisks to diskWithAllParts since
@@ -305,15 +312,8 @@ func (er erasureObjects) healObject(ctx context.Context, bucket string, object s
 	// used here for reconstruction. This is done to ensure that
 	// we do not skip drives that have inconsistent metadata to be
 	// skipped from purging when they are stale.
-	availableDisks, dataErrs := disksWithAllParts(ctx, storageDisks, partsMetadata,
-		errs, bucket, object, scanMode)
-
-	// Latest FileInfo for reference. If a valid metadata is not
-	// present, it is as good as object not found.
-	latestMeta, err := pickValidFileInfo(ctx, partsMetadata, modTime, result.DataBlocks)
-	if err != nil {
-		return result, toObjectErr(err, bucket, object, versionID)
-	}
+	availableDisks, dataErrs := disksWithAllParts(ctx, onlineDisks, partsMetadata,
+		errs, latestMeta, bucket, object, scanMode)
 
 	// Loop to find number of disks with valid data, per-drive
 	// data state and a list of outdated disks on which data needs

cmd/erasure-healing_test.go

@@ -416,7 +416,7 @@ func TestHealObjectCorrupted(t *testing.T) {
 	}
 
 	fileInfos, errs := readAllFileInfo(ctx, erasureDisks, bucket, object, "", false)
-	fi, err := getLatestFileInfo(ctx, fileInfos, errs, er.defaultParityCount)
+	fi, err := getLatestFileInfo(ctx, fileInfos, errs)
 	if err != nil {
 		t.Fatalf("Failed to getLatestFileInfo - %v", err)
 	}
@@ -441,7 +441,7 @@ func TestHealObjectCorrupted(t *testing.T) {
 	}
 
 	fileInfos, errs = readAllFileInfo(ctx, erasureDisks, bucket, object, "", false)
-	nfi, err := getLatestFileInfo(ctx, fileInfos, errs, er.defaultParityCount)
+	nfi, err := getLatestFileInfo(ctx, fileInfos, errs)
 	if err != nil {
 		t.Fatalf("Failed to getLatestFileInfo - %v", err)
 	}
@@ -467,7 +467,7 @@ func TestHealObjectCorrupted(t *testing.T) {
 	}
 
 	fileInfos, errs = readAllFileInfo(ctx, erasureDisks, bucket, object, "", false)
-	nfi, err = getLatestFileInfo(ctx, fileInfos, errs, er.defaultParityCount)
+	nfi, err = getLatestFileInfo(ctx, fileInfos, errs)
 	if err != nil {
 		t.Fatalf("Failed to getLatestFileInfo - %v", err)
 	}

cmd/erasure-metadata.go

@@ -390,15 +390,11 @@ func writeUniqueFileInfo(ctx context.Context, disks []StorageAPI, bucket, prefix
 // writeQuorum is the min required disks to write data.
 func objectQuorumFromMeta(ctx context.Context, partsMetaData []FileInfo, errs []error, defaultParityCount int) (objectReadQuorum, objectWriteQuorum int, err error) {
 	// get the latest updated Metadata and a count of all the latest updated FileInfo(s)
-	latestFileInfo, err := getLatestFileInfo(ctx, partsMetaData, errs, defaultParityCount)
+	latestFileInfo, err := getLatestFileInfo(ctx, partsMetaData, errs)
 	if err != nil {
 		return 0, 0, err
 	}
 
-	if !latestFileInfo.IsValid() {
-		return 0, 0, errErasureReadQuorum
-	}
-
 	parityBlocks := globalStorageClass.GetParityForSC(latestFileInfo.Metadata[xhttp.AmzStorageClass])
 	if parityBlocks <= 0 {
 		parityBlocks = defaultParityCount