dlm: master - dlm_controld: Reset fs_notified when check_fs_done

[David Teigland]

Gitweb:        http://git.fedorahosted.org/git/dlm.git?p=dlm.git;a=commitdiff;h=70a61dc4d5d...
Commit:        70a61dc4d5d91119da30a7165e70bb9646a6d6c1
Parent:        9ccd853b6d36e99af1100548d1e389fc921f10d4
Author:        Jiaju Zhang 
AuthorDate:    Mon Nov 8 16:07:31 2010 -0600
Committer:     David Teigland 
CommitterDate: Tue Feb 22 11:09:10 2011 -0600

dlm_controld: Reset fs_notified when check_fs_done

This situation only seems to arise with ocfs2_controld.
Copying bug description from email
https://www.redhat.com/archives/cluster-devel/2010-November/msg00004.html
> About the issue that dlm_controld and fs_controld sit spinning,
> retrying and replying for the fs_notified check, I have a suspision
> that another scenario may also hit that logic:
>
> If the node->fs_notified has been set to 1 by previous change, when a
> new change comes and needs to check the node->fs_notified, because it
> has not been reset to 0, so check_fs_done will succeed even if
> dlm_controld has not received the notification from fs_controld this
> time.
> For example, given that the following membership changes n, n+1, n+2,
> we see what happens on node X:
> Step 1: cg n: node Y leaves with CPG_REASON_NODEDOWN reason,
>         eventually in node X's ls->node_history, node Y's fs_notified
>         = 1
> Step 2: cg n+1: node Y joins ...
> Step 3: cg n+2: node Y leaves with CPG_REASON_NODEDOWN reason, one
>         possible scenario is: before fs_controld's notification
>         arrives, dlm_controld has known node Y is down from CPG
>         message and done a lot of work, and it saw node Y's
>         fs_notified = 1 (been set in Step 1) then passed the fs check
>         wrongly. So node Y's check_fs reset to 0.
> Step 4: fs_controld's notification arrives, it sees node Y's check_fs
>         = 0 and assumes dlm_controld has not known node Y is down and
>         retries to send the notification. But in fact, dlm_controld
>         has already known this and finished all the work, which will
>         result in the spinning ...

Signed-off-by: Jiaju Zhang 
Signed-off-by: David Teigland 
---
 group/dlm_controld/cpg.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/group/dlm_controld/cpg.c b/group/dlm_controld/cpg.c
index 9b0d223..12cb202 100644
--- a/group/dlm_controld/cpg.c
+++ b/group/dlm_controld/cpg.c
@@ -651,6 +651,7 @@ static int check_fs_done(struct lockspace *ls)
    	if (node->fs_notified) {
    		log_group(ls, "check_fs nodeid %d clear", node->nodeid);
    		node->check_fs = 0;
+			node->fs_notified = 0;
    	} else {
    		log_group(ls, "check_fs nodeid %d needs fs notify",
    			  node->nodeid);