From fceef849cf709ff280865615142f0e68120f7dbf Mon Sep 17 00:00:00 2001
From: Jane Lusby <jane@zfnd.org>
Date: Mon, 30 Nov 2020 16:47:44 -0800
Subject: [PATCH] remove unused mutability to defuse deadlock

---
 zebrad/src/components/tracing/component.rs | 2 +-
 zebrad/src/components/tracing/endpoint.rs  | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/zebrad/src/components/tracing/component.rs b/zebrad/src/components/tracing/component.rs
index 0d0e56a3..491dba73 100644
--- a/zebrad/src/components/tracing/component.rs
+++ b/zebrad/src/components/tracing/component.rs
@@ -55,7 +55,7 @@ impl Tracing {
     /// Reload the currently-active filter with the supplied value.
     ///
     /// This can be used to provide a dynamic tracing filter endpoint.
-    pub fn reload_filter(&mut self, filter: impl Into<EnvFilter>) {
+    pub fn reload_filter(&self, filter: impl Into<EnvFilter>) {
         self.filter_handle
             .reload(filter)
             .expect("the subscriber is not dropped before the component is");
diff --git a/zebrad/src/components/tracing/endpoint.rs b/zebrad/src/components/tracing/endpoint.rs
index b406cacf..353bd0ba 100644
--- a/zebrad/src/components/tracing/endpoint.rs
+++ b/zebrad/src/components/tracing/endpoint.rs
@@ -104,10 +104,10 @@ To set the filter, POST the new filter string to /filter:
             .expect("response with known status code cannot fail"),
         (&Method::POST, "/filter") => match read_filter(req).await {
             Ok(filter) => {
-                app_writer()
-                    .state_mut()
+                app_reader()
+                    .state()
                     .components
-                    .get_downcast_mut::<Tracing>()
+                    .get_downcast_ref::<Tracing>()
                     .expect("Tracing component should be available")
                     .reload_filter(filter);