cifs: don't refresh cached referrals from unactive mounts

There is no point refreshing cached referrals from unactive mounts as
they will no longer be used and new mounts will either create or
refresh them anyway.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/dfs_cache.c

@@ -1549,74 +1549,6 @@ static void refresh_mounts(struct cifs_ses **sessions)
 	}
 }
 
-static void refresh_cache(struct cifs_ses **sessions)
-{
-	int i;
-	struct cifs_ses *ses;
-	unsigned int xid;
-	char *ref_paths[CACHE_MAX_ENTRIES];
-	int count = 0;
-	struct cache_entry *ce;
-
-	/*
-	 * Refresh all cached entries.  Get all new referrals outside critical section to avoid
-	 * starvation while performing SMB2 IOCTL on broken or slow connections.
-
-	 * The cache entries may cover more paths than the active mounts
-	 * (e.g. domain-based DFS referrals or multi tier DFS setups).
-	 */
-	down_read(&htable_rw_lock);
-	for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
-		struct hlist_head *l = &cache_htable[i];
-
-		hlist_for_each_entry(ce, l, hlist) {
-			if (count == ARRAY_SIZE(ref_paths))
-				goto out_unlock;
-			if (hlist_unhashed(&ce->hlist) || !cache_entry_expired(ce) ||
-			    IS_ERR(find_ipc_from_server_path(sessions, ce->path)))
-				continue;
-			ref_paths[count++] = kstrdup(ce->path, GFP_ATOMIC);
-		}
-	}
-
-out_unlock:
-	up_read(&htable_rw_lock);
-
-	for (i = 0; i < count; i++) {
-		char *path = ref_paths[i];
-		struct dfs_info3_param *refs = NULL;
-		int numrefs = 0;
-		int rc = 0;
-
-		if (!path)
-			continue;
-
-		ses = find_ipc_from_server_path(sessions, path);
-		if (IS_ERR(ses))
-			goto next_referral;
-
-		xid = get_xid();
-		rc = get_dfs_referral(xid, ses, path, &refs, &numrefs);
-		free_xid(xid);
-
-		if (!rc) {
-			down_write(&htable_rw_lock);
-			ce = lookup_cache_entry(path);
-			/*
-			 * We need to re-check it because other tasks might have it deleted or
-			 * updated.
-			 */
-			if (!IS_ERR(ce) && cache_entry_expired(ce))
-				update_cache_entry_locked(ce, refs, numrefs);
-			up_write(&htable_rw_lock);
-		}
-
-next_referral:
-		kfree(path);
-		free_dfs_info_array(refs, numrefs);
-	}
-}
-
 /*
  * Worker that will refresh DFS cache and active mounts based on lowest TTL value from a DFS
  * referral.
@@ -1654,11 +1586,8 @@ static void refresh_cache_worker(struct work_struct *work)
 		i += count;
 	}
 
-	if (sessions[0]) {
-		/* Refresh all active mounts and cached entries */
+	if (sessions[0])
 		refresh_mounts(sessions);
-		refresh_cache(sessions);
-	}
 
 	list_for_each_entry_safe(mg, tmp_mg, &mglist, refresh_list) {
 		list_del_init(&mg->refresh_list);