From 00a0ee189959bf71913981482119f4836d25b632 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Mon, 26 Apr 2021 14:16:12 +0100
Subject: [PATCH] vfs: fix modtime changing when reading file into cache -
 fixes #5277

Before this change but after:

aea8776a4368ee8a vfs: fix modtimes not updating when writing via cache #4763

When a file was opened read-only the modtime was read from the cached
file. However this modtime wasn't correct leading to an incorrect
result.

This change fixes the definition of `item.IsDirty` to be true only
when the data is dirty. This fixes the problem as a read only file
isn't considered dirty.
---
 vfs/vfscache/cache.go | 2 +-
 vfs/vfscache/item.go  | 9 +--------
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/vfs/vfscache/cache.go b/vfs/vfscache/cache.go
index 3a3cf2bc6..7427e9d0e 100644
--- a/vfs/vfscache/cache.go
+++ b/vfs/vfscache/cache.go
@@ -549,7 +549,7 @@ func (c *Cache) purgeClean(quota int64) {
 
 	// Make a slice of clean cache files
 	for _, item := range c.item {
-		if !item.IsDataDirty() {
+		if !item.IsDirty() {
 			items = append(items, item)
 		}
 	}
diff --git a/vfs/vfscache/item.go b/vfs/vfscache/item.go
index 7c42563c8..1d07c57ff 100644
--- a/vfs/vfscache/item.go
+++ b/vfs/vfscache/item.go
@@ -450,15 +450,8 @@ func (item *Item) Dirty() {
 	item.mu.Unlock()
 }
 
-// IsDirty returns true if the item is dirty
+// IsDirty returns true if the item data is dirty
 func (item *Item) IsDirty() bool {
-	item.mu.Lock()
-	defer item.mu.Unlock()
-	return item.metaDirty || item.info.Dirty
-}
-
-// IsDataDirty returns true if the item's data is dirty
-func (item *Item) IsDataDirty() bool {
 	item.mu.Lock()
 	defer item.mu.Unlock()
 	return item.info.Dirty