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
this.verifyAction = new VerifyNodeRepositoryAction(transportService, clusterService, this);
        this.repositoriesStatsArchive = new RepositoriesStatsArchive(
            REPOSITORIES_STATS_ARCHIVE_RETENTION_PERIOD.get(settings),
            REPOSITORIES_STATS_ARCHIVE_MAX_ARCHIVED_STATS.get(settings),
            threadPool::relativeTimeInMillis
        );
        this.preRestoreChecks = preRestoreChecks;
    }
    /**
     * Registers new repository in the cluster
     * <p>
     * This method can be only called on the master node. It tries to create a new repository on the master
     * and if it was successful it adds new repository to cluster metadata.
     *
     * @param request  register repository request
     * @param listener register repository listener
     */
    public void registerRepository(final PutRepositoryRequest request, final ActionListener<AcknowledgedResponse> listener) {
        assert lifecycle.started() : "Trying to register new repository but service is in state [" + lifecycle.state() + "]";
        validateRepositoryName(request.name());
        
        try {
            validateRepositoryCanBeCreated(request);
        } catch (Exception e) {
            listener.onFailure(e);
            return;
        }
        final StepListener<AcknowledgedResponse> acknowledgementStep = new StepListener<>();
        final StepListener<Boolean> publicationStep = new StepListener<>(); 
        if (request.verify()) {