Adding separate toggle to purge absent vols

While this toggle is basically required to clean out entries for deleted volumes, having a separate description + toggling this separately seems like a good idea so people get a chance to check if their volumes are all mounted/connected as expected.

Also renamed forcePurge to just purge.

weed/shell/command_volume_fsck.go

@@ -64,7 +64,8 @@ func (c *commandVolumeFsck) Do(args []string, commandEnv *CommandEnv, writer io.
 	verbose := fsckCommand.Bool("v", false, "verbose mode")
 	findMissingChunksInFiler := fsckCommand.Bool("findMissingChunksInFiler", false, "see \"help volume.fsck\"")
 	findMissingChunksInFilerPath := fsckCommand.String("findMissingChunksInFilerPath", "/", "used together with findMissingChunksInFiler")
-	applyPurging := fsckCommand.Bool("forcePurge", false, "<expert only!> after detection, delete missing data from volumes / delete missing file entries from filer")
+	applyPurging := fsckCommand.Bool("purge", false, "<expert only!> after detection, delete missing data from volumes / delete missing file entries from filer")
+	purgeAbsent := fsckCommand.Bool("purgeAbsent", false, "<expert only!> delete missing file entries from filer if the corresponding volume is missing for any reason, please ensure all still existing/expected volumes are connected! used together with findMissingChunksInFiler")
 	if err = fsckCommand.Parse(args); err != nil {
 		return nil
 	}
@@ -101,7 +102,7 @@ func (c *commandVolumeFsck) Do(args []string, commandEnv *CommandEnv, writer io.
 
 	if *findMissingChunksInFiler {
 		// collect all filer file ids and paths
-		if err = c.collectFilerFileIdAndPaths(volumeIdToVInfo, tempFolder, writer, *findMissingChunksInFilerPath, *verbose, *applyPurging); err != nil {
+		if err = c.collectFilerFileIdAndPaths(volumeIdToVInfo, tempFolder, writer, *findMissingChunksInFilerPath, *verbose, *purgeAbsent); err != nil {
 			return fmt.Errorf("collectFilerFileIdAndPaths: %v", err)
 		}
 		// for each volume, check filer file ids
@@ -122,7 +123,7 @@ func (c *commandVolumeFsck) Do(args []string, commandEnv *CommandEnv, writer io.
 	return nil
 }
 
-func (c *commandVolumeFsck) collectFilerFileIdAndPaths(volumeIdToServer map[uint32]VInfo, tempFolder string, writer io.Writer, filerPath string, verbose bool, applyPurging bool) error {
+func (c *commandVolumeFsck) collectFilerFileIdAndPaths(volumeIdToServer map[uint32]VInfo, tempFolder string, writer io.Writer, filerPath string, verbose bool, purgeAbsent bool) error {
 
 	if verbose {
 		fmt.Fprintf(writer, "checking each file from filer ...\n")
@@ -179,8 +180,8 @@ func (c *commandVolumeFsck) collectFilerFileIdAndPaths(volumeIdToServer map[uint
 				// fmt.Fprintf(writer, "%d,%x%08x %d %s\n", i.vid, i.fileKey, i.cookie, len(i.path), i.path)
 			} else {
 				fmt.Fprintf(writer, "%d,%x%08x %s volume not found\n", i.vid, i.fileKey, i.cookie, i.path)
-				if applyPurging {
-					fmt.Printf("deleting path %s for volume not found", i.path)
+				if purgeAbsent {
+					fmt.Printf("deleting path %s after volume not found", i.path)
 					c.httpDelete(i.path, verbose)
 				}
 			}