feat(storcon): forward gc blocking and unblocking (#8956)

Currently using gc blocking and unblocking with storage controller
managed pageservers is painful. Implement the API on storage controller.

Fixes: #8893

pageserver/client/src/lib.rs

@@ -1,2 +1,20 @@
 pub mod mgmt_api;
 pub mod page_service;
+
+/// For timeline_block_unblock_gc, distinguish the two different operations. This could be a bool.
+// If file structure is per-kind not per-feature then where to put this?
+#[derive(Clone, Copy)]
+pub enum BlockUnblock {
+    Block,
+    Unblock,
+}
+
+impl std::fmt::Display for BlockUnblock {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let s = match self {
+            BlockUnblock::Block => "block",
+            BlockUnblock::Unblock => "unblock",
+        };
+        f.write_str(s)
+    }
+}

pageserver/client/src/mgmt_api.rs

@@ -12,6 +12,8 @@ use utils::{
 
 pub use reqwest::Body as ReqwestBody;
 
+use crate::BlockUnblock;
+
 pub mod util;
 
 #[derive(Debug, Clone)]
@@ -454,6 +456,20 @@ impl Client {
             .map_err(Error::ReceiveBody)
     }
 
+    pub async fn timeline_block_unblock_gc(
+        &self,
+        tenant_shard_id: TenantShardId,
+        timeline_id: TimelineId,
+        dir: BlockUnblock,
+    ) -> Result<()> {
+        let uri = format!(
+            "{}/v1/tenant/{tenant_shard_id}/timeline/{timeline_id}/{dir}_gc",
+            self.mgmt_api_endpoint,
+        );
+
+        self.request(Method::POST, &uri, ()).await.map(|_| ())
+    }
+
     pub async fn tenant_reset(&self, tenant_shard_id: TenantShardId) -> Result<()> {
         let uri = format!(
             "{}/v1/tenant/{}/reset",