ksmbd: avoid reclaiming expired durable opens by the client

The expired durable opens should not be reclaimed by client.
This patch add ->durable_scavenger_timeout to fp and check it in
ksmbd_lookup_durable_fd().
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/vfs_cache.c

@@ -477,7 +477,10 @@ struct ksmbd_file *ksmbd_lookup_durable_fd(unsigned long long id)
 	struct ksmbd_file *fp;
 
 	fp = __ksmbd_lookup_fd(&global_ft, id);
-	if (fp && fp->conn) {
+	if (fp && (fp->conn ||
+		   (fp->durable_scavenger_timeout &&
+		    (fp->durable_scavenger_timeout <
+		     jiffies_to_msecs(jiffies))))) {
 		ksmbd_put_durable_fd(fp);
 		fp = NULL;
 	}
@@ -718,6 +721,10 @@ static bool session_fd_check(struct ksmbd_tree_connect *tcon,
 	fp->tcon = NULL;
 	fp->volatile_id = KSMBD_NO_FID;
 
+	if (fp->durable_timeout)
+		fp->durable_scavenger_timeout =
+			jiffies_to_msecs(jiffies) + fp->durable_timeout;
+
 	return true;
 }
 

fs/smb/server/vfs_cache.h

@@ -101,6 +101,7 @@ struct ksmbd_file {
 	struct list_head		lock_list;
 
 	int				durable_timeout;
+	int				durable_scavenger_timeout;
 
 	/* if ls is happening on directory, below is valid*/
 	struct ksmbd_readdir_data	readdir_data;