Re: [Drbd-dev] DRBD8: drbd nodes deadlock in WFBitMapT

[Philipp Reisner <philipp.reisner@linbit.com>]

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Am Montag, 2. April 2007 23:44 schrieb Montrose, Ernest:
> Phil,
> OK...I have learned a tad more since that last email.  So before I even
> try the proposed patch here is a way I was able to duplicate the
> problem.
> Perhaps that will help a bit.  Here it is with two nodes 'a' and 'b' .
> Suppose
> They are in steady states with UUIDS:
> Xa:0:Ha:HH:1:1:0:1:0:0
> Xb:0:Hb:HH:1:1:0:1:0:0
> Role Secondary/Secondary
>
> 1) Disconnect/detach /dev/drbdX on nodea
> 2) Move Current UUID of nodea to history-UUID of nodea and set
> current_UUID of nodea to 00000000000 with drbdmeta..
> 0:0:Xa:HH:1:1:0:1:0:0
> 3) Now attach and connect /dev/drbdX and the problem will occur
>
> I have attached the logs for my "manufactured" version of the problem
>

Ernest,

You are right, that DRBD should get out of this situation. The attached
patch fixes this. (I will commit it when you confirm that it also fixes
the issue for your)

But I am still asking myself how the CRASHED_PRIMARY got lost. Ernest,
do you still have the log of jerry from Mar 23 13:16:54 ?

I would really like to see the last 30 lines before Mar 23 13:16:54.

Thanks!
-Phil
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
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Index: drbd_receiver.c
===================================================================
--- drbd_receiver.c	(revision 2822)
+++ drbd_receiver.c	(working copy)
@@ -1890,7 +1890,7 @@
 
 	*rule_nr = 5;
 	peer = mdev->p_uuid[Bitmap] & ~((u64)1);
-	if (self == peer) return -1;
+	if (self == peer && self != ((u64)0)) return -1;
 
 	*rule_nr = 6;
 	for ( i=History_start ; i<=History_end ; i++ ) {
@@ -1901,7 +1901,7 @@
 	*rule_nr = 7;
 	self = mdev->bc->md.uuid[Bitmap] & ~((u64)1);
 	peer = mdev->p_uuid[Current] & ~((u64)1);
-	if (self == peer) return 1;
+	if (self == peer && self != ((u64)0)) return 1;
 
 	*rule_nr = 8;
 	for ( i=History_start ; i<=History_end ; i++ ) {