Merge pull request ceph#58288 from cbodley/wip-66705

rgw: fix multipart get part when count==1

Reviewed-by: Matt Benjamin <[email protected]>
Reviewed-by: Daniel Gryniewicz <[email protected]>

Author: cbodley

src/rgw/driver/rados/rgw_rados.cc

@@ -6650,12 +6650,15 @@ static int get_part_obj_state(const DoutPrefixProvider* dpp, optional_yield y,
   }
   // navigate to the requested part in the manifest
   RGWObjManifest::obj_iterator end = manifest->obj_end(dpp);
-  if (end.get_cur_part_id() == 0) { // not multipart
+  const int last_part_id = end.get_cur_part_id();
+  if (last_part_id == 0) { // not multipart
     ldpp_dout(dpp, 20) << "object does not have a multipart manifest" << dendl;
     return -ERR_INVALID_PART;
   }
   if (parts_count) {
-    *parts_count = end.get_cur_part_id() - 1;
+    // when a multipart upload only contains a single part, the last part id
+    // is off by one. don't let parts_count go to 0
+    *parts_count = std::max(1, last_part_id - 1);
   }
   ldpp_dout(dpp, 20) << "seeking to part #" << part_num
       << " in the object manifest" << dendl;
@@ -6715,7 +6718,7 @@ static int get_part_obj_state(const DoutPrefixProvider* dpp, optional_yield y,
   do {
     ++iter;
     gen.create_next(iter.get_ofs() - part_offset);
-  } while (iter.get_cur_part_id() == part_num);
+  } while (iter != end && iter.get_cur_part_id() == part_num);
 
   // update the object size
   sm->state.size = part_manifest.get_obj_size();