vfs: fix rename of directory containing files to be uploaded

Before this change, if you renamed a directory containg files yet to
be uploaded then deleted the directory the files would still be
uploaded.

This fixes the problem by changing the directory path in all the file
objects in a directory when it is renamed. This wasn't necessary until
we introduced virtual files and directories which lived beyond the
directory flush mechanism.

Fixes #6809

vfs/dir.go

@@ -325,10 +325,15 @@ func (d *Dir) renameTree(dirPath string) {
 		d.entry = fs.NewDirCopy(context.TODO(), d.entry).SetRemote(dirPath)
 	}
 
-	// Do the same to any child directories
+	// Do the same to any child directories and files
 	for leaf, node := range d.items {
-		if dir, ok := node.(*Dir); ok {
-			dir.renameTree(path.Join(dirPath, leaf))
+		switch x := node.(type) {
+		case *Dir:
+			x.renameTree(path.Join(dirPath, leaf))
+		case *File:
+			x.renameDir(dirPath)
+		default:
+			panic("bad dir entry")
 		}
 	}
 }

vfs/file.go

@@ -141,6 +141,13 @@ func (f *File) Node() Node {
 	return f
 }
 
+// renameDir - call when parent directory has been renamed
+func (f *File) renameDir(dPath string) {
+	f.mu.RLock()
+	f.dPath = dPath
+	f.mu.RUnlock()
+}
+
 // applyPendingRename runs a previously set rename operation if there are no
 // more remaining writers. Call without lock held.
 func (f *File) applyPendingRename() {