[DLM] don't overwrite castparam if it's NULL
If the castaddr passed to the userland API is NULL then don't overwrite the
existing castparam. This allows a different thread to cancel a lock request and
the CANCEL AST gets delivered to the original thread.
bz#306391 (for RHEL4) refers.
Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 2082daf..031229f 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -4429,7 +4429,8 @@
if (lvb_in && ua->lksb.sb_lvbptr)
memcpy(ua->lksb.sb_lvbptr, lvb_in, DLM_USER_LVB_LEN);
- ua->castparam = ua_tmp->castparam;
+ if (ua_tmp->castparam)
+ ua->castparam = ua_tmp->castparam;
ua->user_lksb = ua_tmp->user_lksb;
error = set_unlock_args(flags, ua, &args);
@@ -4474,7 +4475,8 @@
goto out;
ua = (struct dlm_user_args *)lkb->lkb_astparam;
- ua->castparam = ua_tmp->castparam;
+ if (ua_tmp->castparam)
+ ua->castparam = ua_tmp->castparam;
ua->user_lksb = ua_tmp->user_lksb;
error = set_unlock_args(flags, ua, &args);
