cmd/mount: honour --no-lock flag

Do not lock the repository if --no-lock global flag is set. This allows
to mount repositories which are archived on a read only system.

Signed-off-by: Sébastien Gross <seb•ɑƬ•chezwam•ɖɵʈ•org>

changelog/unreleased/pull-2821

@@ -0,0 +1,8 @@
+Change: Honor the --no-lock flag in the mount command
+
+The mount command now does not lock the repository if given the
+--no-lock flag. This allows to mount repositories which are archived
+on a read only backend/filesystem.
+
+https://github.com/restic/restic/issues/1597
+https://github.com/restic/restic/pull/2821

cmd/restic/cmd_mount.go

@@ -90,10 +90,12 @@ func mount(opts MountOptions, gopts GlobalOptions, mountpoint string) error {
 		return err
 	}
 
-	lock, err := lockRepo(repo)
-	defer unlockRepo(lock)
-	if err != nil {
-		return err
+	if !gopts.NoLock {
+		lock, err := lockRepo(repo)
+		defer unlockRepo(lock)
+		if err != nil {
+			return err
+		}
 	}
 
 	err = repo.LoadIndex(gopts.ctx)