use local variable and fix debug log message
diff --git a/src/http/ngx_http_copy_filter_module.c b/src/http/ngx_http_copy_filter_module.c
index 5587ba4..61c3cb2 100644
--- a/src/http/ngx_http_copy_filter_module.c
+++ b/src/http/ngx_http_copy_filter_module.c
@@ -89,7 +89,7 @@
     }
 
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                   "copy filter: \"%V?%V\"", &r->uri, &r->args);
+                   "http copy filter: \"%V?%V\"", &r->uri, &r->args);
 
     ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module);
 
@@ -136,8 +136,8 @@
         r->buffered |= NGX_HTTP_COPY_BUFFERED;
     }
 
-    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
-                   "copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args);
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args);
 
     return rc;
 }