heal: Include more use case of not healable but readable objects (#248) (#20776)

If one object has many parts where all parts are readable but some parts
are missing from some drives, this object can be sometimes un-healable,
which is wrong.

This commit will avoid reading from drives that have missing, corrupted or
outdated xl.meta. It will also check if any part is unreadable to avoid
healing in that case.

cmd/erasure-metadata-utils.go

@@ -295,34 +295,34 @@ func shuffleDisksAndPartsMetadata(disks []StorageAPI, partsMetadata []FileInfo,
 	return shuffledDisks, shuffledPartsMetadata
 }
 
-// Return shuffled partsMetadata depending on distribution.
-func shufflePartsMetadata(partsMetadata []FileInfo, distribution []int) (shuffledPartsMetadata []FileInfo) {
+func shuffleWithDist[T any](input []T, distribution []int) []T {
 	if distribution == nil {
-		return partsMetadata
+		return input
 	}
-	shuffledPartsMetadata = make([]FileInfo, len(partsMetadata))
-	// Shuffle slice xl metadata for expected distribution.
-	for index := range partsMetadata {
+	shuffled := make([]T, len(input))
+	for index := range input {
 		blockIndex := distribution[index]
-		shuffledPartsMetadata[blockIndex-1] = partsMetadata[index]
+		shuffled[blockIndex-1] = input[index]
 	}
-	return shuffledPartsMetadata
+	return shuffled
+}
+
+// Return shuffled partsMetadata depending on distribution.
+func shufflePartsMetadata(partsMetadata []FileInfo, distribution []int) []FileInfo {
+	return shuffleWithDist[FileInfo](partsMetadata, distribution)
+}
+
+// shuffleCheckParts - shuffle CheckParts slice depending on the
+// erasure distribution.
+func shuffleCheckParts(parts []int, distribution []int) []int {
+	return shuffleWithDist[int](parts, distribution)
 }
 
 // shuffleDisks - shuffle input disks slice depending on the
 // erasure distribution. Return shuffled slice of disks with
 // their expected distribution.
-func shuffleDisks(disks []StorageAPI, distribution []int) (shuffledDisks []StorageAPI) {
-	if distribution == nil {
-		return disks
-	}
-	shuffledDisks = make([]StorageAPI, len(disks))
-	// Shuffle disks for expected distribution.
-	for index := range disks {
-		blockIndex := distribution[index]
-		shuffledDisks[blockIndex-1] = disks[index]
-	}
-	return shuffledDisks
+func shuffleDisks(disks []StorageAPI, distribution []int) []StorageAPI {
+	return shuffleWithDist[StorageAPI](disks, distribution)
 }
 
 // evalDisks - returns a new slice of disks where nil is set if