quota: Handle quotas without quota inodes in dquot_get_state()

Make dquot_get_state() gracefully handle a situation when there are no
quota files present even though quotas are enabled.
Signed-off-by: Jan Kara <jack@suse.cz>

fs/quota/dquot.c

@@ -2787,8 +2787,10 @@ int dquot_get_state(struct super_block *sb, struct qc_state *state)
 			tstate->flags |= QCI_LIMITS_ENFORCED;
 		tstate->spc_timelimit = mi->dqi_bgrace;
 		tstate->ino_timelimit = mi->dqi_igrace;
+		if (dqopt->files[type]) {
 			tstate->ino = dqopt->files[type]->i_ino;
 			tstate->blocks = dqopt->files[type]->i_blocks;
+		}
 		tstate->nextents = 1;	/* We don't know... */
 		spin_unlock(&dq_data_lock);
 	}