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

cmd/erasure-healing-common.go

@@ -179,53 +179,6 @@ func listOnlineDisks(disks []StorageAPI, partsMetadata []FileInfo, errs []error)
 	return onlineDisks, modTime
 }
 
-// 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
-}
-
 // disksWithAllParts - This function needs to be called with
 // []StorageAPI returned by listOnlineDisks. Returns,
 //

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) {

cmd/erasure-metadata.go

@@ -394,21 +394,73 @@ func writeUniqueFileInfo(ctx context.Context, disks []StorageAPI, bucket, prefix
 	return evalDisks(disks, mErrs), err
 }
 
+func commonParity(parities []int) int {
+	occMap := make(map[int]int)
+	for _, p := range parities {
+		occMap[p]++
+	}
+
+	var maxOcc, commonParity int
+
+	for parity, occ := range occMap {
+		if parity == -1 {
+			// Ignore non defined parity
+			continue
+		}
+		if occ >= maxOcc {
+			maxOcc = occ
+			commonParity = parity
+		}
+	}
+
+	if maxOcc == 0 {
+		// Did not found anything useful
+		return -1
+	}
+	return commonParity
+}
+
+func listObjectParities(partsMetadata []FileInfo, errs []error) (parities []int) {
+	parities = make([]int, len(partsMetadata))
+	for index, metadata := range partsMetadata {
+		if errs[index] != nil {
+			parities[index] = -1
+			continue
+		}
+		parities[index] = metadata.Erasure.ParityBlocks
+	}
+	return
+}
+
 // Returns per object readQuorum and writeQuorum
 // readQuorum is the min required disks to read data.
 // 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)
+	// There should be atleast half correct entries, if not return failure
-	latestFileInfo, err := getLatestFileInfo(ctx, partsMetaData, defaultParityCount, errs)
+	expectedRQuorum := len(partsMetaData) / 2
-	if err != nil {
+	if defaultParityCount == 0 {
-		return 0, 0, err
+		// 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 -1, -1, reducedErr
 	}
 
-	if latestFileInfo.Deleted {
 	// special case when parity is '0'
 	if defaultParityCount == 0 {
 		return len(partsMetaData), len(partsMetaData), nil
 	}
+
+	parities := listObjectParities(partsMetaData, errs)
+	parityBlocks := commonParity(parities)
+
+	if parityBlocks < 0 {
+		return -1, -1, errErasureReadQuorum
+	}
+
+	if parityBlocks == 0 {
 		// For delete markers do not use 'defaultParityCount' as it is not expected to be the case.
 		// Use maximum allowed read quorum instead, writeQuorum+1 is returned for compatibility sake
 		// but there are no callers that shall be using this.
@@ -416,23 +468,7 @@ func objectQuorumFromMeta(ctx context.Context, partsMetaData []FileInfo, errs []
 		return readQuorum, readQuorum + 1, nil
 	}
 
-	parityBlocks := globalStorageClass.GetParityForSC(latestFileInfo.Metadata[xhttp.AmzStorageClass])
+	dataBlocks := len(partsMetaData) - parityBlocks
-	if parityBlocks < 0 {
-		parityBlocks = defaultParityCount
-	}
-
-	// For erasure code upgraded objects choose the parity
-	// blocks saved internally, instead of 'defaultParityCount'
-	if _, ok := latestFileInfo.Metadata[minIOErasureUpgraded]; ok {
-		if latestFileInfo.Erasure.ParityBlocks != 0 {
-			parityBlocks = latestFileInfo.Erasure.ParityBlocks
-		}
-	}
-
-	dataBlocks := latestFileInfo.Erasure.DataBlocks
-	if dataBlocks == 0 {
-		dataBlocks = len(partsMetaData) - parityBlocks
-	}
 
 	writeQuorum := dataBlocks
 	if dataBlocks == parityBlocks {