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.
test/framework/src/main/java/org/elasticsearch/snapshots/AbstractSnapshotIntegTestCase.java
});
        } else {
            logger.info("--> skipped repo consistency checks because [{}]", skipRepoConsistencyCheckReason);
        }
    }
    protected void disableRepoConsistencyCheck(String reason) {
        assertNotNull(reason);
        skipRepoConsistencyCheckReason = reason;
    }
    protected RepositoryData getRepositoryData(String repoName, Version version) {
        final RepositoryData repositoryData = getRepositoryData(repoName);
        if (SnapshotsService.includesUUIDs(version) == false) {
            return repositoryData.withoutUUIDs();
        } else {
            return repositoryData;
        }
    }
    @SuppressWarnings("cast")
    protected RepositoryData getRepositoryData(String repository) {
        return getRepositoryData((Repository) getRepositoryOnMaster(repository));
    }
    protected RepositoryData getRepositoryData(Repository repository) {
        return PlainActionFuture.get(repository::getRepositoryData);
    }
    public static long getFailureCount(String repository) {
        long failureCount = 0;
        for (RepositoriesService repositoriesService : internalCluster().getDataOrMasterNodeInstances(RepositoriesService.class)) {
            MockRepository mockRepository = (MockRepository) repositoriesService.repository(repository);
            failureCount += mockRepository.getFailureCount();
        }