[DLM] fix requestqueue race
Red Hat BZ 211914
There's a race between dlm_recoverd (1) enabling locking and (2) clearing
out the requestqueue, and dlm_recvd (1) checking if locking is enabled and
(2) adding a message to the requestqueue. An order of recoverd(1),
recvd(1), recvd(2), recoverd(2) will result in a message being left on the
requestqueue. The fix is to have dlm_recvd check if dlm_recoverd has
enabled locking after taking the mutex for the requestqueue and if it has
processing the message instead of queueing it.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 3f2befa..6088a16 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3028,10 +3028,17 @@
while (1) {
if (dlm_locking_stopped(ls)) {
- if (!recovery)
- dlm_add_requestqueue(ls, nodeid, hd);
- error = -EINTR;
- goto out;
+ if (recovery) {
+ error = -EINTR;
+ goto out;
+ }
+ error = dlm_add_requestqueue(ls, nodeid, hd);
+ if (error == -EAGAIN)
+ continue;
+ else {
+ error = -EINTR;
+ goto out;
+ }
}
if (lock_recovery_try(ls))