SUNRPC/cache: Allow garbage collection of invalid cache entries

If the cache entry never gets initialised, we want the garbage collector to be able to evict it. Otherwise if the upcall daemon fails to initialise the entry, we end up never expiring it. Signed-off-by: Trond Myklebust <[email protected]> [ cel: resolved a merge conflict ] Signed-off-by: Chuck Lever <[email protected]>
wangyan0507 · Mar 16, 2020 · 277f27e · 277f27e
1 parent 65286b8
commit 277f27e
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Showing 2 changed files with 19 additions and 20 deletions.
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
@@ -209,9 +209,6 @@ static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
 
 static inline bool cache_is_expired(struct cache_detail *detail, struct cache_head *h)
 {
-	if (!test_bit(CACHE_VALID, &h->flags))
-		return false;
-
 	return  (h->expiry_time < seconds_since_boot()) ||
 		(detail->flush_time >= h->last_refresh);
 }

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
@@ -64,13 +64,14 @@ static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(tmp, head, cache_list) {
-		if (detail->match(tmp, key)) {
-			if (cache_is_expired(detail, tmp))
-				continue;
-			tmp = cache_get_rcu(tmp);
-			rcu_read_unlock();
-			return tmp;
-		}
+		if (!detail->match(tmp, key))
+			continue;
+		if (test_bit(CACHE_VALID, &tmp->flags) &&
+		    cache_is_expired(detail, tmp))
+			continue;
+		tmp = cache_get_rcu(tmp);
+		rcu_read_unlock();
+		return tmp;
 	}
 	rcu_read_unlock();
 	return NULL;
@@ -114,17 +115,18 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
 	/* check if entry appeared while we slept */
 	hlist_for_each_entry_rcu(tmp, head, cache_list,
 				 lockdep_is_held(&detail->hash_lock)) {
-		if (detail->match(tmp, key)) {
-			if (cache_is_expired(detail, tmp)) {
-				sunrpc_begin_cache_remove_entry(tmp, detail);
-				freeme = tmp;
-				break;
-			}
-			cache_get(tmp);
-			spin_unlock(&detail->hash_lock);
-			cache_put(new, detail);
-			return tmp;
+		if (!detail->match(tmp, key))
+			continue;
+		if (test_bit(CACHE_VALID, &tmp->flags) &&
+		    cache_is_expired(detail, tmp)) {
+			sunrpc_begin_cache_remove_entry(tmp, detail);
+			freeme = tmp;
+			break;
 		}
+		cache_get(tmp);
+		spin_unlock(&detail->hash_lock);
+		cache_put(new, detail);
+		return tmp;
 	}
 
 	hlist_add_head_rcu(&new->cache_list, head);