heal: Should delete stale object parts before healing (#3649)

cmd/xl-v1-healing.go

@@ -344,22 +344,34 @@ func healObject(storageDisks []StorageAPI, bucket string, object string, quorum
 			// Not an outdated disk.
 			continue
 		}
-		if errs[index] != nil {
+
-			// If there was an error (most likely errFileNotFound)
+		// errFileNotFound implies that xl.json is missing. We
+		// may have object parts still present in the object
+		// directory. This needs to be deleted for object to
+		// healed successfully.
+		if errs[index] != nil && !isErr(errs[index], errFileNotFound) {
 			continue
 		}
+
 		// Outdated object with the same name exists that needs to be deleted.
 		outDatedMeta := partsMetadata[index]
-		// Delete all the parts.
+		// Consult valid metadata picked when there is no
-		for partIndex := 0; partIndex < len(outDatedMeta.Parts); partIndex++ {
+		// metadata available on this disk.
-			err := disk.DeleteFile(bucket, pathJoin(object, outDatedMeta.Parts[partIndex].Name))
+		if isErr(errs[index], errFileNotFound) {
-			if err != nil {
+			outDatedMeta = latestMeta
+		}
+
+		// Delete all the parts. Ignore if parts are not found.
+		for _, part := range outDatedMeta.Parts {
+			err := disk.DeleteFile(bucket, pathJoin(object, part.Name))
+			if err != nil && !isErr(err, errFileNotFound) {
 				return traceError(err)
 			}
 		}
-		// Delete xl.json file.
+
+		// Delete xl.json file. Ignore if xl.json not found.
 		err := disk.DeleteFile(bucket, pathJoin(object, xlMetaJSONFile))
-		if err != nil {
+		if err != nil && !isErr(err, errFileNotFound) {
 			return traceError(err)
 		}
 	}