fix(admin): advertise IAM admin capabilities in runtime capabilities

The v4 runtime capabilities response carried no admin.iam.* entries, so
the rc client's capability gate rejected policy detach even though the
detach route is implemented (rustfs/backlog#1900). Advertise the IAM
admin capability set as a flat named list whose statuses are derived
from the public admin route inventory, so the advertisement tracks the
actually registered routes instead of a hardcoded claim.

crates/ecstore/src/bucket/bucket_target_sys.rs

@@ -866,7 +866,7 @@ impl BucketTargetSys {
             return Some(cli);
         }
 
-        // TODO(backlog): spawn an async task to proactively reload the replication target
+        // TODO: spawn a task to reload the target
         if self.is_reloading_target(bucket, arn).await {
             return None;
         }

crates/ecstore/src/cluster/rpc/peer_s3_client.rs

@@ -454,7 +454,7 @@ impl S3PeerSys {
                 }
             }
             topology_complete &= bucket_map.values().all(|count| *count >= quorum);
-            // TODO(backlog): integrate MRF backlog stats into scanner bucket listing
+            // TODO: MRF
         }
 
         let mut buckets: Vec<BucketInfo> = result_map.into_values().collect();

crates/ecstore/src/cluster/rpc/remote_disk.rs

@@ -2406,7 +2406,7 @@ impl DiskAPI for RemoteDisk {
             return errors;
         }
 
-        // TODO(backlog): replace string errors with typed `StorageError` variants
+        // TODO: use Error not string
 
         let result = self
             .execute_with_timeout(

crates/ecstore/src/core/sets.rs

@@ -249,7 +249,7 @@ impl Sets {
 
         self.connect_disks().await;
 
-        // TODO(backlog): make monitor_and_connect interval configurable instead of hardcoded 15s
+        // TODO: config interval
         let mut interval = tokio::time::interval(Duration::from_secs(15));
         loop {
             tokio::select! {

crates/ecstore/src/disk/local.rs

@@ -5215,8 +5215,8 @@ impl LocalDisk {
 
         let cache = Cache::new(update_fn, Duration::from_secs(1), Opts::default());
 
-        // TODO(backlog): add O_DIRECT I/O support for performance-critical paths
-        // TODO(backlog): populate DiskInfo in constructor
+        // TODO: DIRECT support
+        // TODD: DiskInfo
         let mut disk = Self {
             root: root.clone(),
             publication_root,
@@ -5751,7 +5751,7 @@ impl LocalDisk {
 
         // return Ok(());
 
-        // TODO(backlog): make disk space checks and trash cleanup event-driven instead of poll-based
+        // TODO: async notifications for disk space checks and trash cleanup
 
         let trash_path = self.io_get_object_path(RUSTFS_META_TMP_DELETED_BUCKET, Uuid::new_v4().to_string().as_str())?;
         // if let Some(parent) = trash_path.parent() {
@@ -5997,7 +5997,7 @@ impl LocalDisk {
 
     #[hotpath::measure(impl_type = "LocalDisk")]
     async fn read_all_data(&self, volume: &str, volume_dir: impl AsRef<Path>, file_path: impl AsRef<Path>) -> Result<Vec<u8>> {
-        // TODO(backlog): add configurable timeout for read_all_data operations
+        // TODO: timeout support
         let (data, _) = self.read_all_data_with_dmtime(volume, volume_dir, file_path).await?;
         Ok(data)
     }
@@ -6674,7 +6674,7 @@ impl LocalDisk {
             return Ok(());
         }
 
-        // TODO(backlog): add directory listing lock to prevent concurrent enumeration
+        // TODO: add lock
 
         let stall = opts.stall_timeout_duration();
 
@@ -8796,7 +8796,7 @@ impl DiskAPI for LocalDisk {
         Ok(entries)
     }
 
-    // TODO(backlog): support io.writer cancellation and early termination in walk_dir
+    // FIXME: TODO: io.writer TODO cancel
     #[tracing::instrument(level = "trace", skip_all)]
     async fn walk_dir<W: AsyncWrite + Unpin + Send>(&self, opts: WalkDirOptions, wr: &mut W) -> Result<()> {
         self.wait_for_startup_cleanup().await;
@@ -9880,7 +9880,7 @@ impl DiskAPI for LocalDisk {
                 );
                 return Err(e);
             }
-            // TODO(backlog): add post-setup disk health verification
+            // TODO: health check
         }
         Ok(())
     }

crates/ecstore/src/layout/endpoints.rs

@@ -249,7 +249,7 @@ impl PoolEndpointList {
             endpoint.set_set_index(0);
             endpoint.set_disk_index(0);
 
-            // TODO(backlog): check for cross-device mounts in single-drive setup
+            // TODO Check for cross device mounts if any.
 
             return Ok(Self {
                 inner: vec![Endpoints::from(vec![endpoint])],
@@ -264,7 +264,7 @@ impl PoolEndpointList {
                 // Convert args to endpoints
                 let mut eps = Endpoints::try_from(set_layout.as_slice())?;
 
-                // TODO(backlog): check for cross-device mounts in multi-pool setup
+                // TODO Check for cross device mounts if any.
 
                 for (disk_idx, ep) in eps.as_mut().iter_mut().enumerate() {
                     ep.set_pool_index(pool_idx);

crates/ecstore/src/object_api/types.rs

@@ -1091,7 +1091,7 @@ impl ObjectInfo {
                     }
                 };
 
-                // TODO(backlog): handle VersionPurgeStatus in object listing
+                // TODO:VersionPurgeStatus
                 let versioned = vcfg.clone().map(|v| v.0.versioned(&entry.name)).unwrap_or_default();
                 objects.push(ObjectInfo::from_file_info(&fi, bucket, &entry.name, versioned));
 

crates/ecstore/src/set_disk/ops/multipart.rs

@@ -1575,7 +1575,7 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
         let parts_metadata = vec![fi.clone(); disks.len()];
 
         if !user_defined.contains_key("content-type") {
-            // TODO(backlog): detect content-type from part data when header is missing
+            // TODO: get content-type
         }
 
         if let Some(sc) = user_defined.get(AMZ_STORAGE_CLASS)
@@ -1971,7 +1971,7 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
                 return Err(Error::InvalidPart(p.part_num, ext_part.etag.clone(), p.etag.clone().unwrap_or_default()));
             }
 
-            // TODO(backlog): integrate encryption verification during complete multipart
+            // TODO: crypto
 
             if (i < uploaded_parts.len() - 1)
                 && !(opts.data_movement && ext_part.actual_size < 0)

crates/ecstore/src/set_disk/ops/object.rs

@@ -6161,7 +6161,7 @@ impl crate::storage_api_contracts::object::ObjectOperations for SetDisks {
 
         join_all(rollback_futures).await;
 
-        // TODO(backlog): support partial object deletion for multi-part objects
+        // TODO: add_partial
 
         if let Some(api) = opts.tier_delete_journal_api.as_ref() {
             for (idx, je) in persisted_journal_entries {
@@ -6371,7 +6371,7 @@ impl crate::storage_api_contracts::object::ObjectOperations for SetDisks {
             }
         }
 
-        // TODO(backlog): integrate lifecycle evaluation before object deletion
+        // TODO: Lifecycle
 
         let mut version_found = true;
         // delete_object_version below derives its own majority quorum from the
@@ -6465,7 +6465,7 @@ impl crate::storage_api_contracts::object::ObjectOperations for SetDisks {
                 mark_deleted: mark_delete,
                 mod_time: Some(mod_time),
                 replication_state_internal: opts.delete_replication.as_ref().map(replication_state_to_filemeta),
-                ..Default::default() // TODO(backlog): populate transition state on delete markers
+                ..Default::default() // TODO: Transition
             };
 
             fi.set_tier_free_version_id(&find_vid.to_string());

crates/ecstore/src/store/bucket.rs

@@ -601,7 +601,7 @@ impl ECStore {
 
     #[instrument(skip(self))]
     pub(super) async fn handle_list_bucket(&self, opts: &BucketOptions) -> Result<Vec<BucketInfo>> {
-        // TODO(backlog): support cached bucket listing via opts.cached
+        // TODO: opts.cached
 
         let mut buckets = self.peer_sys.list_bucket(opts).await?;
 

crates/ecstore/src/store/list_objects.rs

@@ -4673,7 +4673,7 @@ async fn gather_results(
             entry.name = entry.name.replace("\\", "/");
         }
 
-        // TODO(backlog): integrate rx.recv() for incremental listing results
+        // TODO: rx.recv()
 
         if let Some(marker) = &opts.marker
             && ((!opts.include_marker && &entry.name <= marker) || (opts.include_marker && &entry.name < marker))
@@ -4703,7 +4703,7 @@ async fn gather_results(
             continue;
         }
 
-        // TODO(backlog): integrate lifecycle evaluation during object listing
+        // TODO: Lifecycle
 
         entries.push(Some(entry));
         candidate_entries += 1;

crates/ecstore/src/store/multipart.rs

@@ -332,7 +332,7 @@ impl ECStore {
         let expected_incarnation_id = opts.expected_bucket_incarnation_id;
 
         if request.prefix.is_empty() {
-            // TODO(backlog): return cached multipart listing when prefix is empty
+            // TODO: return from cache
         }
 
         if self.single_pool() {
@@ -610,7 +610,7 @@ impl ECStore {
         let (opts, _bucket_lifecycle_guard) = self.guard_multipart_bucket_incarnation(bucket, opts).await?;
         let opts = &opts;
 
-        // TODO(backlog): defer DeleteUploadID to background for faster abort response
+        // TODO: defer DeleteUploadID
 
         if self.single_pool() {
             return self.pools[0].abort_multipart_upload(bucket, object, upload_id, opts).await;

crates/ecstore/src/store/rebalance.rs

@@ -385,7 +385,7 @@ impl ECStore {
     }
 
     pub(super) async fn is_suspended(&self, idx: usize) -> bool {
-        // TODO(backlog): acquire pool metadata lock for consistent suspension check
+        // TODO: LOCK
 
         let pool_meta = self.pool_meta.read().await;
 

rustfs/src/admin/handlers/system.rs

@@ -70,6 +70,12 @@ const SITE_REPLICATION_EDIT_ROUTE: &str = "/rustfs/admin/v3/site-replication/edi
 const SITE_REPLICATION_RESYNC_ROUTE: &str = "/rustfs/admin/v3/site-replication/resync/op";
 const SITE_REPLICATION_REPAIR_ROUTE: &str = "/rustfs/admin/v3/site-replication/repair";
 const SITE_REPLICATION_REPAIR_STATUS_ROUTE: &str = "/rustfs/admin/v3/site-replication/repair/status";
+const IAM_POLICY_ATTACH_ROUTE: &str = "/rustfs/admin/v3/idp/builtin/policy/attach";
+const IAM_POLICY_DETACH_ROUTE: &str = "/rustfs/admin/v3/idp/builtin/policy/detach";
+const IAM_POLICY_ENTITIES_ROUTE: &str = "/rustfs/admin/v3/idp/builtin/policy-entities";
+const IAM_ACCESS_KEYS_BULK_ROUTE: &str = "/rustfs/admin/v3/list-access-keys-bulk";
+const IAM_ACCESS_KEYS_BULK_LDAP_ROUTE: &str = "/rustfs/admin/v3/idp/ldap/list-access-keys-bulk";
+const IAM_ACCESS_KEYS_BULK_OPENID_ROUTE: &str = "/rustfs/admin/v3/idp/openid/list-access-keys-bulk";
 
 macro_rules! log_system_request_rejected {
     ($operation:expr, $reason:expr) => {
@@ -661,9 +667,24 @@ pub struct RuntimeCapabilitiesSummary {
     pub manual_transition_jobs: CapabilityStatus,
 }
 
+/// One named admin capability advertised to management clients
+/// (rustfs/backlog#1900). `name` is a cross-repo wire contract: the rc
+/// client gates commands on these exact strings (see rustfs/cli
+/// `IAM_POLICY_DETACH_CAPABILITY` etc.), so entries may be added but
+/// existing names must never be renamed or removed.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+pub struct AdvertisedAdminCapability {
+    pub name: &'static str,
+    pub status: CapabilityStatus,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize)]
 pub struct RuntimeCapabilitiesResponse {
     pub summary: RuntimeCapabilitiesSummary,
+    /// Additive field: absent in responses from older servers, so clients
+    /// must treat a missing list as "no dynamic advertisement" and fall
+    /// back to their pinned per-version contract.
+    pub advertised: Vec<AdvertisedAdminCapability>,
     pub replication: ReplicationCapabilities,
     pub manual_transition_jobs: ManualTransitionJobCapabilities,
     pub diagnostic_probes: DiagnosticProbeCapabilities,
@@ -986,6 +1007,7 @@ pub(crate) async fn build_runtime_capabilities_response()
 
     Ok(RuntimeCapabilitiesResponse {
         summary,
+        advertised: advertised_admin_capabilities(),
         replication: ReplicationCapabilities::current(),
         manual_transition_jobs: ManualTransitionJobCapabilities::current(),
         diagnostic_probes: DiagnosticProbeCapabilities::current(),
@@ -1077,6 +1099,23 @@ fn admin_route_capability(method: HttpMethod, path: &str) -> CapabilityStatus {
     admin_route_capability_from_inventory(method, path, ADMIN_ROUTE_POLICY_SPECS, DEFERRED_ADMIN_ROUTE_POLICIES)
 }
 
+fn advertised_admin_capabilities() -> Vec<AdvertisedAdminCapability> {
+    [
+        ("admin.iam.policy-attach", HttpMethod::Post, IAM_POLICY_ATTACH_ROUTE),
+        ("admin.iam.policy-detach", HttpMethod::Post, IAM_POLICY_DETACH_ROUTE),
+        ("admin.iam.policy-entities", HttpMethod::Get, IAM_POLICY_ENTITIES_ROUTE),
+        ("admin.iam.access-keys-bulk", HttpMethod::Get, IAM_ACCESS_KEYS_BULK_ROUTE),
+        ("admin.iam.access-keys-bulk.ldap", HttpMethod::Get, IAM_ACCESS_KEYS_BULK_LDAP_ROUTE),
+        ("admin.iam.access-keys-bulk.openid", HttpMethod::Get, IAM_ACCESS_KEYS_BULK_OPENID_ROUTE),
+    ]
+    .into_iter()
+    .map(|(name, method, route)| AdvertisedAdminCapability {
+        name,
+        status: admin_route_capability(method, route),
+    })
+    .collect()
+}
+
 fn admin_route_capability_from_inventory(
     method: HttpMethod,
     path: &str,
@@ -1239,6 +1278,48 @@ mod tests {
         );
     }
 
+    /// Wire-contract pin (rustfs/backlog#1900): the rc client keys its
+    /// command gates on these exact capability names, and parses each
+    /// entry as `{name, status: {state, reason?}}`. Renaming or dropping
+    /// a name silently disables the corresponding rc command.
+    #[tokio::test]
+    async fn runtime_capabilities_response_advertises_iam_capabilities() {
+        let response = build_runtime_capabilities_response()
+            .await
+            .expect("runtime capabilities response should build");
+
+        let expected_supported = [
+            "admin.iam.policy-attach",
+            "admin.iam.policy-detach",
+            "admin.iam.policy-entities",
+            "admin.iam.access-keys-bulk",
+            "admin.iam.access-keys-bulk.ldap",
+            "admin.iam.access-keys-bulk.openid",
+        ];
+        for name in expected_supported {
+            let entry = response
+                .advertised
+                .iter()
+                .find(|capability| capability.name == name)
+                .unwrap_or_else(|| panic!("{name} must be advertised"));
+            assert_eq!(entry.status.state, CapabilityState::Supported, "{name} must be supported");
+        }
+
+        let mut names: Vec<&str> = response.advertised.iter().map(|capability| capability.name).collect();
+        let total = names.len();
+        names.sort_unstable();
+        names.dedup();
+        assert_eq!(names.len(), total, "advertised capability names must be unique");
+
+        let serialized = serde_json::to_value(&response).expect("response should serialize");
+        let advertised = serialized["advertised"].as_array().expect("advertised must be an array");
+        let detach = advertised
+            .iter()
+            .find(|entry| entry["name"] == "admin.iam.policy-detach")
+            .expect("serialized detach entry must exist");
+        assert_eq!(detach["status"]["state"], "supported");
+    }
+
     #[tokio::test]
     async fn runtime_capabilities_response_reports_missing_topology_before_storage_init() {
         let response = build_runtime_capabilities_response()