LU-1428 ldlm: fix a race in ldlm_lock_destroy_internal

[fs/lustre-release.git] / lustre / ldlm / ldlm_lock.c

diff --git a/lustre/ldlm/ldlm_lock.c b/lustre/ldlm/ldlm_lock.c
index 550cc1c..09126de 100644 (file)
--- a/lustre/ldlm/ldlm_lock.c
+++ b/lustre/ldlm/ldlm_lock.c
@@ -335,10 +335,12 @@ int ldlm_lock_destroy_internal(struct ldlm_lock *lock)
         }
         lock->l_destroyed = 1;
 
-        if (lock->l_export && lock->l_export->exp_lock_hash &&
-            !cfs_hlist_unhashed(&lock->l_exp_hash))
-                cfs_hash_del(lock->l_export->exp_lock_hash,
-                             &lock->l_remote_handle, &lock->l_exp_hash);
+       if (lock->l_export && lock->l_export->exp_lock_hash) {
+               /* NB: it's safe to call cfs_hash_del() even lock isn't
+                * in exp_lock_hash. */
+               cfs_hash_del(lock->l_export->exp_lock_hash,
+                            &lock->l_remote_handle, &lock->l_exp_hash);
+       }
 
         ldlm_lock_remove_from_lru(lock);
         class_handle_unhash(&lock->l_handle);
@@ -1818,11 +1820,17 @@ int ldlm_lock_set_data(struct lustre_handle *lockh, void *data)
 }
 EXPORT_SYMBOL(ldlm_lock_set_data);
 
+struct export_cl_data {
+       struct obd_export       *ecl_exp;
+       int                     ecl_loop;
+};
+
 int ldlm_cancel_locks_for_export_cb(cfs_hash_t *hs, cfs_hash_bd_t *bd,
                                     cfs_hlist_node_t *hnode, void *data)
 
 {
-        struct obd_export    *exp  = data;
+       struct export_cl_data   *ecl = (struct export_cl_data *)data;
+       struct obd_export       *exp  = ecl->ecl_exp;
         struct ldlm_lock     *lock = cfs_hash_object(hs, hnode);
         struct ldlm_resource *res;
 
@@ -1835,13 +1843,28 @@ int ldlm_cancel_locks_for_export_cb(cfs_hash_t *hs, cfs_hash_bd_t *bd,
         ldlm_reprocess_all(res);
         ldlm_resource_putref(res);
         LDLM_LOCK_RELEASE(lock);
-        return 0;
+
+       ecl->ecl_loop++;
+       if ((ecl->ecl_loop & -ecl->ecl_loop) == ecl->ecl_loop) {
+               CDEBUG(D_INFO,
+                      "Cancel lock %p for export %p (loop %d), still have "
+                      "%d locks left on hash table.\n",
+                      lock, exp, ecl->ecl_loop,
+                      cfs_atomic_read(&hs->hs_count));
+       }
+
+       return 0;
 }
 
 void ldlm_cancel_locks_for_export(struct obd_export *exp)
 {
-        cfs_hash_for_each_empty(exp->exp_lock_hash,
-                                ldlm_cancel_locks_for_export_cb, exp);
+       struct export_cl_data   ecl = {
+               .ecl_exp        = exp,
+               .ecl_loop       = 0,
+       };
+
+       cfs_hash_for_each_empty(exp->exp_lock_hash,
+                               ldlm_cancel_locks_for_export_cb, &ecl);
 }
 
 /**