rgw: modify radoslist to better support the rgw-gap-list tool

When the `radosgw-admin bucket radoslist ...` sub-command was
introduced, it was written specifically for finding orphans. It has
since been updated to work for finding gaps, that is indexed RGW
objects that are missing one or more supporting rados objects.

When a head object was not found, it was ignored. Now it does produce
output with the oid and related information for the missing head
object.

Signed-off-by: J. Eric Ivancich <[email protected]>

Author: ivancich

src/rgw/radosgw-admin/orphan.cc

@@ -1066,18 +1066,30 @@ int RGWRadosList::pop_and_handle_stat_op(
   RGWRados::Object::Stat& front_op = ops.front();
 
   int ret = front_op.wait(dpp);
-  if (ret < 0) {
-    if (ret != -ENOENT) {
-      ldpp_dout(dpp, -1) << "ERROR: stat_async() returned error: " <<
-	cpp_strerror(-ret) << dendl;
-    }
-    goto done;
-  }
+  if (ret == -ENOENT) {
+    const auto& result = front_op.result;
+    const rgw_bucket& bucket = result.obj.bucket;
+    const std::string oid = bucket.marker + "_" + result.obj.get_oid();
+    obj_oids.insert(oid);
 
-  ret = handle_stat_result(dpp, front_op.result, bucket_name, obj_key, obj_oids);
-  if (ret < 0) {
-    ldpp_dout(dpp, -1) << "ERROR: handle_stat_result() returned error: " <<
+    // needed for the processing below
+    bucket_name = result.obj.bucket.name;
+    obj_key = result.obj.key;
+
+    ldpp_dout(dpp, -1) << "ERROR: " << __func__ <<
+      ": stat of head object resulted in ENOENT; oid=" << oid << dendl;
+  } else if (ret < 0) {
+    ldpp_dout(dpp, -1) << "ERROR: " << __func__ <<
+      ": stat_async() returned error: " <<
       cpp_strerror(-ret) << dendl;
+    goto done;
+  } else {
+    ret = handle_stat_result(dpp, front_op.result, bucket_name, obj_key, obj_oids);
+    if (ret < 0) {
+      ldpp_dout(dpp, -1) << "ERROR: " << __func__ <<
+	": handle_stat_result() returned error: " <<
+	cpp_strerror(-ret) << dendl;
+    }
   }
 
   // output results
@@ -1099,6 +1111,7 @@ int RGWRadosList::pop_and_handle_stat_op(
   obj_ctx.invalidate(front_op.result.obj);
 
   ops.pop_front();
+
   return ret;
 }