RE: [Drbd-dev] DRBD 8 rejects some state changes that it shouldn't

RE: [Drbd-dev] DRBD 8 rejects some state changes that it shouldn't

[Graham, Simon]

> 
> I think you the bug you mean is the missing ChgStateHard in
> receive_state(). But before patching it in there, I wait for your
> reply.
> 

I agree - this seems like the right fix to me.
Simon

Re: [Drbd-dev] DRBD 8 rejects some state changes that it shouldn't

[Philipp Reisner]

Am Dienstag, 8. August 2006 19:47 schrieb Graham, Simon:
> > I think you the bug you mean is the missing ChgStateHard in
> > receive_state(). But before patching it in there, I wait for your
> > reply.
>
> I agree - this seems like the right fix to me.
> Simon

Ok, here it the fix...
http://lists.linbit.com/pipermail/drbd-cvs/2006-August/001182.html

-Phil
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :

[Drbd-dev] DRBD 8 rejects some state changes that it shouldn't

[Graham, Simon]

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In general, the state change code does the right thing in refusing
invalid state changes, however there are some cases where it rejects a
change that cannot really be rejected - for example, if the peer tells
you that it has gone diskless, it's really not possible to refuse the
state change - here's an example:

drbd15: State change failed: Refusing to be inconsistent on both
nodesdrbd15:   state = { cs:SyncTarget st:Secondary/Primary
ds:Inconsistent/UpToDate r--- }drbd15:  wanted = { cs:SyncTarget
st:Secondary/Primary ds:Inconsistent/Diskless r--- }
I'm not sure how important this is but it definitely results in the
local state being incorrect. I'm not totally sure but I suspect you
should always let the peer state change by setting the ChgStateHard flag
in the call to drbd_change_state in receive_req_state?

Simon

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Re: [Drbd-dev] DRBD 8 rejects some state changes that it shouldn't

[Philipp Reisner]

Am Montag, 7. August 2006 15:12 schrieb Graham, Simon:
> In general, the state change code does the right thing in refusing
> invalid state changes, however there are some cases where it rejects a
> change that cannot really be rejected - for example, if the peer tells
> you that it has gone diskless, it's really not possible to refuse the
> state change - here's an example:
>
> drbd15: State change failed: Refusing to be inconsistent on both
> nodesdrbd15:   state = { cs:SyncTarget st:Secondary/Primary
> ds:Inconsistent/UpToDate r--- }drbd15:  wanted = { cs:SyncTarget
> st:Secondary/Primary ds:Inconsistent/Diskless r--- }

> I'm not sure how important this is but it definitely results in the
> local state being incorrect. I'm not totally sure but I suspect you
> should always let the peer state change by setting the ChgStateHard flag
> in the call to drbd_change_state in receive_req_state?

The idea is to know the correct state of the peer.

In case the peer's disk failes, it (should) origin in
drbd_io_error() -> drbd_send_state()  ===network==>> 
receive_state() /* Hmm, here is ChgStateHard missing!!! */

If the user at the peer node wants to detach, it should go
through _drbd_request_state() -> drbd_send_state_req()
==network==>>  receive_req_state() ...

if the state change failes there, it should fail the
state change on the peer node as well...


I think you the bug you mean is the missing ChgStateHard in
receive_state(). But before patching it in there, I wait for your
reply.

-Philipp
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :