xl: Rename 'xl.json' to 'file.json' (#1461)

Fixes #1460

file-json.md

@@ -1,6 +1,6 @@
-### xl.json
+### file.json
 
-``xl.json`` is a special file captured and written by XL storage API layer
+``file.json`` is a special file captured and written by XL storage API layer
 to interpret, manage and extract erasured data to multiple disks.
 
 ```json
@@ -9,6 +9,7 @@ to interpret, manage and extract erasured data to multiple disks.
     "stat": {
         "size": 24256,
         "modTime": "2016-04-28T00:11:37.843Z",
+        "delete": false,
         "version": 0
     },
     "erasure": {
@@ -30,6 +31,7 @@ to interpret, manage and extract erasured data to multiple disks.
 
   - "size"     // Size of the file.
   - "modTime"  // Modified time of the file.
+  - "deleted"  // Field to track if the file is deleted when disks are down.
   - "version"  // File version tracked when disks are down.
 
 - "erasure" // Erasure metadata for the written file.

xl-erasure-v1-common.go

@@ -112,7 +112,7 @@ func (xl XL) listOnlineDisks(volume, path string) (onlineDisks []StorageAPI, mda
 	return onlineDisks, mdata, heal, nil
 }
 
-// Get xl.json metadata as a map slice.
+// Get file.json metadata as a map slice.
 // Returns error slice indicating the failed metadata reads.
 // Read lockNS() should be done by caller.
 func (xl XL) getPartsMetadata(volume, path string) ([]xlMetaV1, []error) {
@@ -130,7 +130,7 @@ func (xl XL) getPartsMetadata(volume, path string) ([]xlMetaV1, []error) {
 
 		metadata, err := xlMetaV1Decode(metadataReader)
 		if err != nil {
-			// Unable to parse xl.json, set error.
+			// Unable to parse file.json, set error.
 			errs[index] = err
 			continue
 		}
@@ -139,8 +139,8 @@ func (xl XL) getPartsMetadata(volume, path string) ([]xlMetaV1, []error) {
 	return metadataArray, errs
 }
 
-// Writes/Updates `xl.json` for given file. updateParts carries
+// Writes/Updates `file.json` for given file. updateParts carries
-// index of disks where `xl.json` needs to be updated.
+// index of disks where `file.json` needs to be updated.
 //
 // Returns collection of errors, indexed in accordance with input
 // updateParts order.

xl-erasure-v1.go

@@ -29,8 +29,8 @@ import (
 )
 
 const (
-	// Part metadata file.
+	// XL erasure metadata file.
-	xlMetaV1File = "xl.json"
+	xlMetaV1File = "file.json"
 	// Maximum erasure blocks.
 	maxErasureBlocks = 16
 )
@@ -590,7 +590,7 @@ func listFiles(disk StorageAPI, volume, prefix, marker string, recursive bool, c
 			markerPath = fsFilesInfo[len(fsFilesInfo)-1].Name
 		}
 		if count == 0 && recursive && !strings.HasSuffix(markerPath, xlMetaV1File) {
-			// If last entry is not xl.json then loop once more to check if we have reached eof.
+			// If last entry is not file.json then loop once more to check if we have reached eof.
 			fsFilesInfo, eof, err = disk.ListFiles(volume, prefix, markerPath, recursive, 1)
 			if err != nil {
 				log.WithFields(logrus.Fields{
@@ -603,17 +603,17 @@ func listFiles(disk StorageAPI, volume, prefix, marker string, recursive bool, c
 				return nil, true, err
 			}
 			if !eof {
-				// file.N and xl.json are always in pairs and hence this
+				// file.N and file.json are always in pairs and hence this
-				// entry has to be xl.json. If not better to manually investigate
+				// entry has to be file.json. If not better to manually investigate
 				// and fix it.
 				// For the next ListFiles() call we can safely assume that the
-				// marker is "object/xl.json"
+				// marker is "object/file.json"
 				if !strings.HasSuffix(fsFilesInfo[0].Name, xlMetaV1File) {
 					log.WithFields(logrus.Fields{
 						"volume":          volume,
 						"prefix":          prefix,
 						"fsFileInfo.Name": fsFilesInfo[0].Name,
-					}).Errorf("ListFiles failed with %s, expected %s to be a xl.json file.", err, fsFilesInfo[0].Name)
+					}).Errorf("ListFiles failed with %s, expected %s to be a file.json file.", err, fsFilesInfo[0].Name)
 					return nil, true, errUnexpected
 				}
 			}