From 264b3f0c900a3023e4f391c32971ca4b3201af3f Mon Sep 17 00:00:00 2001
From: Saleh Dindar <salh@fb.com>
Date: Sun, 24 Sep 2023 14:51:08 -0700
Subject: [PATCH] vfs: [bugfix] Update dir modification time

A subtle bug where dir modification time is not updated when the dir already exists
in the cache. It is only noticeable when some clients use dir modification time to
invalidate cache.
---
 vfs/dir.go | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/vfs/dir.go b/vfs/dir.go
index 511d8db4a..5044ee855 100644
--- a/vfs/dir.go
+++ b/vfs/dir.go
@@ -694,9 +694,10 @@ func (d *Dir) _readDirFromEntries(entries fs.DirEntries, dirTree dirtree.DirTree
 			if node == nil || !node.IsDir() {
 				node = newDir(d.vfs, d.f, d, item)
 			}
+			dir := node.(*Dir)
+			dir.mu.Lock()
+			dir.modTime = item.ModTime(context.TODO())
 			if dirTree != nil {
-				dir := node.(*Dir)
-				dir.mu.Lock()
 				err = dir._readDirFromDirTree(dirTree, when)
 				if err != nil {
 					dir.read = time.Time{}
@@ -704,10 +705,10 @@ func (d *Dir) _readDirFromEntries(entries fs.DirEntries, dirTree dirtree.DirTree
 					dir.read = when
 					dir.cleanupTimer.Reset(d.vfs.Opt.DirCacheTime * 2)
 				}
-				dir.mu.Unlock()
-				if err != nil {
-					return err
-				}
+			}
+			dir.mu.Unlock()
+			if err != nil {
+				return err
 			}
 		default:
 			err = fmt.Errorf("unknown type %T", item)