- Added preventative locking in two areas, where we're walking shared lists

- Fixed a subtle race condition in ldlm_local_lock_enqueue: we checked to see if
  a completion AST had been received and then acted, with no lock.  This fixes
  the assertion that I was seeing yesterday.

diff --git a/lustre/ldlm/ldlm_extent.c b/lustre/ldlm/ldlm_extent.c
index 4f7f9eb..a89aed0 100644 (file)
--- a/lustre/ldlm/ldlm_extent.c
+++ b/lustre/ldlm/ldlm_extent.c
@@ -79,9 +79,11 @@ int ldlm_extent_policy(struct ldlm_lock *lock, void *req_cookie,
         if (!res)
                 LBUG();
 
+        l_lock(&res->lr_namespace->ns_lock);
         policy_internal(&res->lr_granted, req_ex, &new_ex, mode);
         policy_internal(&res->lr_converting, req_ex, &new_ex, mode);
         policy_internal(&res->lr_waiting, req_ex, &new_ex, mode);
+        l_unlock(&res->lr_namespace->ns_lock);
 
         memcpy(&lock->l_extent, &new_ex, sizeof(new_ex));
 

diff --git a/lustre/ldlm/ldlm_lock.c b/lustre/ldlm/ldlm_lock.c
index 02cf2a2..de02509 100644 (file)
--- a/lustre/ldlm/ldlm_lock.c
+++ b/lustre/ldlm/ldlm_lock.c
@@ -649,6 +649,7 @@ ldlm_error_t ldlm_lock_enqueue(struct ldlm_lock * lock,
         lock->l_cookie = cookie;
         lock->l_cookie_len = cookie_len;
 
+        l_lock(&res->lr_namespace->ns_lock);
         if (local && lock->l_req_mode == lock->l_granted_mode) {
                 /* The server returned a blocked lock, but it was granted before
                  * we got a chance to actually enqueue it.  We don't need to do
@@ -695,6 +696,7 @@ ldlm_error_t ldlm_lock_enqueue(struct ldlm_lock * lock,
         ldlm_grant_lock(lock);
         EXIT;
       out:
+        l_unlock(&res->lr_namespace->ns_lock);
         /* Don't set 'completion_ast' until here so that if the lock is granted
          * immediately we don't do an unnecessary completion call. */
         lock->l_completion_ast = completion;
@@ -830,7 +832,7 @@ struct ldlm_resource *ldlm_lock_convert(struct ldlm_lock *lock, int new_mode,
         } else {
                 /* FIXME: We should try the conversion right away and possibly
                  * return success without the need for an extra AST */
-                list_add_tail(&lock->l_res_link, &res->lr_converting);
+                ldlm_resource_add_lock(res, res->lr_converting.prev, lock);
                 *flags |= LDLM_FL_BLOCK_CONV;
         }