Quota code uses 'uid' or '(1 << 32) + gid' as the hash key, however, the quota hash function lqs_hash() always try to interpret such a unsigned long long key as a 'quota_adjust_qunit' struct, then calculate the hash value by quota_adjust_qunit->qaq_id, since the misused key->qaq_id most likely be a certain value (0 or something else), the calculated hash value for all uid/gid will be same.

I think this problem might be introduced by some landing or hash converting long time ago, since we can still store/fetch the qunit for each uig/gid (though they are always in same bucket), the bug was not detected by any test.