Should NVME_SC_INVALID_NS be translated to BLK_STS_IOERR instead of BLK_STS_NOTSUPP so that multipath(both native and dm) can failover on the failure?

[Jirong Feng]

I've tested the patch basing on kernel version 6.6.0. It seems not 
working...

here's my steps & results:

1. create a VM and make & install kernel from source applying the patch.

[root at fjr-nvmet-1 ~]# uname -r
6.6.0-mytest+

2. clone that VM.

3. create a shared volume and attach to the both VMs.

4. config nvmet as below:

VM1:

o- / 
......................................................................................................................... 
[...]
   o- hosts 
................................................................................................................... 
[...]
   o- ports 
................................................................................................................... 
[...]
   | o- 1 ................................................ [trtype=tcp, 
traddr=192.168.111.99, trsvcid=4420, inline_data_size=262144]
   |   o- ana_groups 
.......................................................................................................... 
[...]
   |   | o- 1 
..................................................................................................... 
[state=optimized]
   |   o- referrals 
........................................................................................................... 
[...]
   |   o- subsystems 
.......................................................................................................... 
[...]
   |     o- 
nqn.2014-08.org.nvmexpress:NVMf:uuid:cf4bb93c-949f-4532-a5c1-b8bd267a4e06 
......................................... [...]
   o- subsystems 
.............................................................................................................. 
[...]
     o- 
nqn.2014-08.org.nvmexpress:NVMf:uuid:cf4bb93c-949f-4532-a5c1-b8bd267a4e06 
[version=1.3, allow_any=1, serial=308df2776344fdd17cba]
       o- allowed_hosts 
....................................................................................................... 
[...]
       o- namespaces 
.......................................................................................................... 
[...]
         o- 1 .......................................... [path=/dev/vdc, 
uuid=cf4bb93c-949f-4532-a5c1-b8bd267a4e06, grpid=1, enabled]

VM2:

o- / 
......................................................................................................................... 
[...]
   o- hosts 
................................................................................................................... 
[...]
   o- ports 
................................................................................................................... 
[...]
   | o- 1 ............................................... [trtype=tcp, 
traddr=192.168.111.111, trsvcid=4420, inline_data_size=262144]
   |   o- ana_groups 
.......................................................................................................... 
[...]
   |   | o- 1 
..................................................................................................... 
[state=optimized]
   |   o- referrals 
........................................................................................................... 
[...]
   |   o- subsystems 
.......................................................................................................... 
[...]
   |     o- 
nqn.2014-08.org.nvmexpress:NVMf:uuid:cf4bb93c-949f-4532-a5c1-b8bd267a4e06 
......................................... [...]
   o- subsystems 
.............................................................................................................. 
[...]
     o- 
nqn.2014-08.org.nvmexpress:NVMf:uuid:cf4bb93c-949f-4532-a5c1-b8bd267a4e06 
[version=1.3, allow_any=1, serial=0dcf77d36826000cc5a0]
       o- allowed_hosts 
....................................................................................................... 
[...]
       o- namespaces 
.......................................................................................................... 
[...]
         o- 1 .......................................... [path=/dev/vdc, 
uuid=cf4bb93c-949f-4532-a5c1-b8bd267a4e06, grpid=1, enabled]

5. create a host vm(CentOS 8.1, kernel version 
4.18.0-147.3.1.el8_1.aarch64), config dm multipath

[root at fjr-vm1 ~]# cat /etc/multipath/conf.d/nvme.conf
devices {
     device {
                 vendor                  "NVME"
                 product                 "Linux"
                 path_selector           "round-robin 0"
                 path_grouping_policy    failover
                 uid_attribute           ID_SERIAL
                 prio                    "ANA"
                 path_checker            "none"
                 #rr_min_io               100
                 #rr_min_io_rq            "1"
                 #fast_io_fail_tmo        15
                 #dev_loss_tmo            600
                 #rr_weight               uniform
                 rr_weight               priorities
                 failback                immediate
                 no_path_retry           queue
     }
}


6. connect nvme on host, finally it looks like:

[root at fjr-vm1 ~]# nvme list
Node             SN Model                                    Namespace 
Usage                      Format           FW Rev
---------------- -------------------- 
---------------------------------------- --------- 
-------------------------- ---------------- --------
/dev/nvme0n1     0dcf77d36826000cc5a0 
Linux                                    1         107.37  GB / 107.37  
GB    512   B +  0 B   6.6.0-my
/dev/nvme1n1     308df2776344fdd17cba 
Linux                                    1         107.37  GB / 107.37  
GB    512   B +  0 B   6.6.0-my

[root at fjr-vm1 ~]# nvme list-subsys
nvme-subsys0 - 
NQN=nqn.2014-08.org.nvmexpress:NVMf:uuid:cf4bb93c-949f-4532-a5c1-b8bd267a4e06
\
  +- nvme0 tcp traddr=192.168.111.111 trsvcid=4420 live
  +- nvme1 tcp traddr=192.168.111.99 trsvcid=4420 live

[root at fjr-vm1 ~]# multipath -ll
mpatha (Linux_0dcf77d36826000cc5a0) dm-0 NVME,Linux
size=100G features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=50 status=active
| `- 1:1:1:1 nvme1n1 259:1 active ready running
`-+- policy='round-robin 0' prio=50 status=enabled
   `- 0:1:1:1 nvme0n1 259:0 active ready running

7. execute fio on host, and disable namespace on the vm corresponding to 
nvme1, the same error goes again:

fio: io_u error on file /dev/dm-0: Operation not supported: write 
offset=14734594048, buflen=4096
fio: io_u error on file /dev/dm-0: Operation not supported: write 
offset=106607394816, buflen=4096
fio: pid=16076, err=95/file:io_u.c:1747, func=io_u error, 
error=Operation not supported