disable index_part upload check

Signed-off-by: Alex Chi Z <chi@neon.tech>

libs/remote_storage/src/local_fs.rs

@@ -570,7 +570,8 @@ impl RemoteStorage for LocalFs {
         encryption_key: Option<&[u8]>,
         cancel: &CancellationToken,
     ) -> anyhow::Result<()> {
-        unimplemented!()
+        self.upload(from, data_size_bytes, to, metadata, cancel)
+            .await
     }
 
     async fn delete_objects(

pageserver/src/tenant/remote_timeline_client.rs

@@ -1495,6 +1495,7 @@ impl RemoteTimelineClient {
         upload_queue.queued_operations.push_back(op);
     }
 
+    #[allow(dead_code)]
     fn is_kms_enabled(&self) -> bool {
         self.kms_impl.is_some()
     }

pageserver/src/tenant/remote_timeline_client/index.rs

@@ -274,14 +274,16 @@ impl IndexPart {
     /// Check for invariants in the index: this is useful when uploading an index to ensure that if
     /// we encounter a bug, we do not persist buggy metadata.
     pub(crate) fn validate(&self) -> Result<(), String> {
-        if self.import_pgdata.is_none()
-            && self.metadata.ancestor_timeline().is_none()
-            && self.layer_metadata.is_empty()
-        {
-            // Unless we're in the middle of a raw pgdata import, or this is a child timeline,the index must
-            // always have at least one layer.
-            return Err("Index has no ancestor and no layers".to_string());
-        }
+        // We have to disable this check: we might need to upload an empty index part with new keys, or new `reldirv2` flag.
+
+        // if self.import_pgdata.is_none()
+        //     && self.metadata.ancestor_timeline().is_none()
+        //     && self.layer_metadata.is_empty()
+        // {
+        //     // Unless we're in the middle of a raw pgdata import, or this is a child timeline,the index must
+        //     // always have at least one layer.
+        //     return Err("Index has no ancestor and no layers".to_string());
+        // }
 
         Ok(())
     }