[Stgt-devel] yet another tgtd iSCSI misbehaviour (aborted journal, remounting ro)

[Tomasz Chmielewski]

FUJITA Tomonori schrieb:
> On Wed, 06 Feb 2008 10:45:54 +0100
> Tomasz Chmielewski <mangoo at wpkg.org> wrote:
> 
>> It seems there is yet another problem (?) in tgtd.
>>
>> It can be easily reproduced when the initiator crashes and then starts 
>> again. I tested it only with diskless machines booted off iSCSI.
>>
>> To reproduce:
>>
>> 1. Start tgtd, apply settings with tgtadm
>> 2. Start a diskless initiator:
>>   a) a diskless initiator fetches the kernel and the initrd via PXE/tftp
>>   b) kernel executes initrd; initrd brings the interface up
>>   c) initrd starts the iSCSI connection with "iscsistart" command from 
>> open-iscsi
>>   d) we switch to a new root, system boots fine
>>   e) IMPORTANT - system starts iscsid now (/etc/init.d/open-iscsi start)
>>
>> So far, everything was fine and unproblematic.
>>
>> 3. Now, crash your initiator machine (i.e. press reboot button)[1].
>>
>> 4. Initiator starts just fine again - the connection was established 
>> with "iscsistart".
>>
>> 5. IMPORTANT - start iscsid now (/etc/init.d/open-iscsi start). The 
>> initiator will report "connection1:0: iscsi: detected conn error (1011)" 
>> and eventually, will break the connection, remount fs readonly etc. 
>> scary things will happen.
>>
>>   a) there is a workaround to that: when initiator reports 
>> "connection1:0: iscsi: detected conn error..." - kill tgtd, and start it 
>> again. Initiator will reconnect flawlessly
>>   b) if you don't kill/start tgtd again, connection will break and fs 
>> will be remounted ro.
>>
>>
>> The issue does not happen with IET or SCST.
>>
>> It looks like:
>> - tgtd has an established connection with an initiator
>> - initiator is killed, but tgtd still thinks initiator is connected
>> to it
> 
> Did you confirm this? 'tgtadm --op show --mode target' shows you the
> active initiators (and its connections).

Yes, as I remember, it was showing multiple initiators connected.



-- 
Tomasz Chmielewski
http://wpkg.org