diff --git a/core/src/services/cos/backend.rs b/core/src/services/cos/backend.rs
index 0a9eb3f3dd6..921f56e7c4a 100644
--- a/core/src/services/cos/backend.rs
+++ b/core/src/services/cos/backend.rs
@@ -315,7 +315,7 @@ impl Access for CosBackend {
         match status {
             StatusCode::OK => {
                 let headers = resp.headers();
-                let mut meta = self.core.parse_metadata(path, resp.headers())?;
+                let meta = self.core.parse_metadata(path, resp.headers())?;
                 Ok(RpStat::new(meta))
             }
             _ => Err(parse_error(resp)),
diff --git a/core/src/services/cos/core.rs b/core/src/services/cos/core.rs
index eccef01ef85..bdbdf58ccae 100644
--- a/core/src/services/cos/core.rs
+++ b/core/src/services/cos/core.rs
@@ -26,9 +26,9 @@ use http::header::CONTENT_LENGTH;
 use http::header::CONTENT_TYPE;
 use http::header::IF_MATCH;
 use http::header::IF_NONE_MATCH;
+use http::HeaderMap;
 use http::Request;
 use http::Response;
-use http::HeaderMap;
 use reqsign::TencentCosCredential;
 use reqsign::TencentCosCredentialLoader;
 use reqsign::TencentCosSigner;