Bug 594511

Description of problem:

dlm_controld checks that a failed node has been fenced by comparing the time it was fenced to the time it properly joined the cpg.  In one of Nate's QE tests, he found a case where the failed node rejoined the cpg just before the fencing time was recorded.  This causes dlm_controld to get stuck waiting for a fencing to occur when it already has.

1274304702 dlm:ls:clvmd conf 2 0 1 memb 1 4 join left 3
1274304702 clvmd add_change cg 2 remove nodeid 3 reason 3
1274304702 clvmd add_change cg 2 counts member 2 joined 0 remove 1 failed 1
1274304702 clvmd stop_kernel cg 2
1274304702 write "0" to "/sys/kernel/dlm/clvmd/control"
1274304702 clvmd check_fencing 3 not fenced add 1274304347 fence 0
1274304702 dlm:ls:clvmd conf 1 0 1 memb 1 join left 4
1274304702 clvmd add_change cg 3 remove nodeid 4 reason 3
1274304702 clvmd add_change cg 3 counts member 1 joined 0 remove 1 failed 1
1274304702 clvmd check_fencing 4 not fenced add 1274304347 fence 0
....
1274304741 cluster node 3 added
...
1274304752 dlm:ls:clvmd conf 2 1 0 memb 1 3 join 3 left
1274304752 clvmd add_change cg 4 joined nodeid 3
1274304752 clvmd add_change cg 4 counts member 2 joined 1 remove 0 failed 0
1274304754 clvmd receive_start 3:1 len 80
1274304754 clvmd match_change 3:1 skip 2 sender not member
1274304754 clvmd match_change 3:1 skip 3 sender not member
1274304754 clvmd match_change 3:1 matches cg 4
1274304754 clvmd check_fencing 3 not fenced add 1274304754 fence 1274304753
1274304754 clvmd check_fencing 4 1274304347 fenced at 1274304753
...
1274304832 dlm:ls:clvmd conf 3 1 0 memb 1 3 4 join 4 left
1274304832 clvmd add_change cg 5 joined nodeid 4
1274304832 clvmd add_change cg 5 counts member 3 joined 1 remove 0 failed 0
1274304832 clvmd receive_start 4:1 len 84
1274304832 clvmd match_change 4:1 skip cg 2 created 1274304702 cluster add 12743
1274304832 clvmd match_change 4:1 skip 3 sender not member
1274304832 clvmd match_change 4:1 skip 4 sender not member
1274304832 clvmd match_change 4:1 matches cg 5
1274304832 clvmd receive_start 3:2 len 84
1274304832 clvmd match_change 3:2 skip 2 sender not member
1274304832 clvmd match_change 3:2 skip 3 sender not member
1274304832 clvmd match_change 3:2 skip 4 already start
1274304832 clvmd match_change 3:2 matches cg 5

This line: clvmd check_fencing 3 not fenced add 1274304754 fence 1274304753
shows that 3 was added to the cpg one second after fenced recorded that fencing was done.  The fenced log confirms that this is when it received the message indicating the 3 was fenced:

1274304753 receive_victim_done 1:3 flags 2 len 80
1274304753 receive_victim_done 1:3 remove victim 3 time 1274304753 how 2

I've not been able to reproduce this, but I believe the fix is for dlm_controld to check that the fencing time is later than the time it saw the node fail instead of later than the time it saw the node most recently join.


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