Today if we detect concurrent modification of a snapshot repository then we mark it with `CORRUPTED_REPO_GEN` which blocks further writes to try and prevent additional damage to its contents. You can remove the marker by calling the register-repository API again, but this API will discard no-op re-registrations without taking any action. You can work around this by unregistering the repository first (which may be impossible if it's still in use for searchable snapshots) or by re-registering it with some trivial setting change (which seems hacky).

We should not consider it a no-op re-registration if the repository is currently marked with `CORRUPTED_REPO_GEN`, because doing this re-registration will re-read the repo contents and clear the corruption marker and therefore is not a no-op.
server/src/main/java/org/elasticsearch/repositories/RepositoriesService.java
} else {
                    repositoriesMetadata.add(repositoryMetadata);
                }
            }
            if (found == false) {
                repositoriesMetadata.add(new RepositoryMetadata(request.name(), request.type(), request.settings()));
            }
            repositories = new RepositoriesMetadata(repositoriesMetadata);
            mdBuilder.putCustom(RepositoriesMetadata.TYPE, repositories);
            changed = true;
            return ClusterState.builder(currentState).metadata(mdBuilder).build();
        }
    }
    /**
     * Ensures that we can create the repository and that it's creation actually works
     * <p>
     * This verification method will create and then close the repository we want to create.
     *
     * @param request
     */
    public void validateRepositoryCanBeCreated(final PutRepositoryRequest request) {
        final RepositoryMetadata newRepositoryMetadata = new RepositoryMetadata(request.name(), request.type(), request.settings());
        
        closeRepository(createRepository(newRepositoryMetadata, typesRegistry, RepositoriesService::throwRepositoryTypeDoesNotExists));
    }
    private void submitUnbatchedTask(@SuppressWarnings("SameParameterValue") String source, ClusterStateUpdateTask task) {
        submitUnbatchedTask(clusterService, source, task);
    }
    @SuppressForbidden(reason = "legacy usage of unbatched task") 
    private static void submitUnbatchedTask(