LU-4801 ldlm: discard l_lock from struct ldlm_lock.

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

diff --git a/lustre/ldlm/ldlm_lockd.c b/lustre/ldlm/ldlm_lockd.c
index 5f331cc..f7a320f 100644 (file)
--- a/lustre/ldlm/ldlm_lockd.c
+++ b/lustre/ldlm/ldlm_lockd.c
@@ -40,6 +40,7 @@
 #include <linux/kthread.h>
 #include <linux/list.h>
 #include <libcfs/libcfs.h>
+#include <libcfs/linux/linux-mem.h>
 #include <lustre_errno.h>
 #include <lustre_dlm.h>
 #include <obd_class.h>
@@ -3372,11 +3373,30 @@ static int ldlm_cleanup(void)
        RETURN(0);
 }
 
+void ldlm_resource_init_once(void *p)
+{
+       /*
+        * It is import to initialise the spinlock only once,
+        * as ldlm_lock_change_resource() could try to lock
+        * the resource *after* it has been freed and possibly
+        * reused. SLAB_TYPESAFE_BY_RCU ensures the memory won't
+        * be freed while the lock is being taken, but we need to
+        * ensure that it doesn't get reinitialized either.
+        */
+       struct ldlm_resource *res = p;
+
+       memset(res, 0, sizeof(*res));
+       mutex_init(&res->lr_lvb_mutex);
+       spin_lock_init(&res->lr_lock);
+}
+
 int ldlm_init(void)
 {
        ldlm_resource_slab = kmem_cache_create("ldlm_resources",
                                               sizeof(struct ldlm_resource), 0,
-                                              SLAB_HWCACHE_ALIGN, NULL);
+                                              SLAB_TYPESAFE_BY_RCU |
+                                              SLAB_HWCACHE_ALIGN,
+                                              ldlm_resource_init_once);
        if (ldlm_resource_slab == NULL)
                return -ENOMEM;
 
@@ -3436,6 +3456,13 @@ void ldlm_exit(void)
 {
        if (ldlm_refcount)
                CERROR("ldlm_refcount is %d in ldlm_exit!\n", ldlm_refcount);
+       /* These two lines should not be needed, but appear to fix
+        * a crash on RHEL7. The slab_cache sometimes gets freed before the
+        * last slab is rcu_freed, and that can cause kmem_freepages()
+        * to free too many pages and trip a BUG
+        */
+       kmem_cache_shrink(ldlm_resource_slab);
+       synchronize_rcu();
        kmem_cache_destroy(ldlm_resource_slab);
        /*
         * ldlm_lock_put() use RCU to call ldlm_lock_free, so need call