Re: [PATCH] ceph: fix incorrectly decoding the mdsmap bug

[Xiubo Li <xiubli@redhat.com>]

On 11/5/21 6:29 PM, Jeff Layton wrote:
> On Fri, 2021-11-05 at 17:34 +0800, xiubli@redhat.com wrote:
>> From: Xiubo Li <xiubli@redhat.com>
>>
>> When decreasing the 'max_mds' in the cephfs cluster, when the extra
>> MDS or MDSes are not removed yet, the mdsmap may only decreased the
>> 'max_mds' but still having the that or those MDSes 'in' or in the
>> export targets list.
>>
>> Signed-off-by: Xiubo Li <xiubli@redhat.com>
>> ---
>>   fs/ceph/mdsmap.c | 4 ----
>>   1 file changed, 4 deletions(-)
>>
>> diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
>> index 61d67cbcb367..30387733765d 100644
>> --- a/fs/ceph/mdsmap.c
>> +++ b/fs/ceph/mdsmap.c
>> @@ -263,10 +263,6 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end, bool msgr2)
>>   				goto nomem;
>>   			for (j = 0; j < num_export_targets; j++) {
>>   				target = ceph_decode_32(&pexport_targets);
>> -				if (target >= m->possible_max_rank) {
>> -					err = -EIO;
>> -					goto corrupt;
>> -				}
>>   				info->export_targets[j] = target;
>>   			}
>>   		} else {
> Thanks Xiubo, looks good. Given the severity when mdsmap decoding fails,
> I think we should probably mark this for stable too. Let me know if you
> have any objections.
Yeah, it should be.