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b=24375 Fix lvb updating race in enqueue vs completion case
[fs/lustre-release.git] / lustre / ldlm / ldlm_request.c
index 46e7607..5d718c9 100644 (file)
@@ -26,7 +26,7 @@
  * GPL HEADER END
  */
 /*
- * Copyright  2008 Sun Microsystems, Inc. All rights reserved
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  */
 /*
@@ -50,6 +50,9 @@ int ldlm_enqueue_min = OBD_TIMEOUT_DEFAULT;
 CFS_MODULE_PARM(ldlm_enqueue_min, "i", int, 0644,
                 "lock enqueue timeout minimum");
 
+/* in client side, whether the cached locks will be canceled before replay */
+unsigned int ldlm_cancel_unused_locks_before_replay = 1;
+
 static void interrupted_completion_wait(void *data)
 {
 }
@@ -78,16 +81,16 @@ int ldlm_expired_completion_wait(void *data)
                         RETURN(0);
 
                 LDLM_ERROR(lock, "lock timed out (enqueued at "CFS_TIME_T", "
-                          CFS_DURATION_T"s ago); not entering recovery in "
+                           CFS_DURATION_T"s ago); not entering recovery in "
                            "server code, just going back to sleep",
-                          lock->l_enqueued_time.tv_sec,
+                           lock->l_last_activity,
                            cfs_time_sub(cfs_time_current_sec(),
-                           lock->l_enqueued_time.tv_sec));
+                           lock->l_last_activity));
                 if (cfs_time_after(cfs_time_current(), next_dump)) {
                         last_dump = next_dump;
                         next_dump = cfs_time_shift(300);
                         ldlm_namespace_dump(D_DLMTRACE,
-                                            lock->l_resource->lr_namespace);
+                                            ldlm_lock_to_ns(lock));
                         if (last_dump == 0)
                                 libcfs_debug_dumplog();
                 }
@@ -99,9 +102,8 @@ int ldlm_expired_completion_wait(void *data)
         ptlrpc_fail_import(imp, lwd->lwd_conn_cnt);
         LDLM_ERROR(lock, "lock timed out (enqueued at "CFS_TIME_T", "
                   CFS_DURATION_T"s ago), entering recovery for %s@%s",
-                  lock->l_enqueued_time.tv_sec,
-                  cfs_time_sub(cfs_time_current_sec(),
-                  lock->l_enqueued_time.tv_sec),
+                  lock->l_last_activity,
+                  cfs_time_sub(cfs_time_current_sec(), lock->l_last_activity),
                   obd2cli_tgt(obd), imp->imp_connection->c_remote_uuid.uuid);
 
         RETURN(0);
@@ -111,13 +113,13 @@ int ldlm_expired_completion_wait(void *data)
    from a single node. */
 int ldlm_get_enq_timeout(struct ldlm_lock *lock)
 {
-        int timeout = at_get(&lock->l_resource->lr_namespace->ns_at_estimate);
+        int timeout = at_get(ldlm_lock_to_ns_at(lock));
         if (AT_OFF)
                 return obd_timeout / 2;
         /* Since these are non-updating timeouts, we should be conservative.
            It would be nice to have some kind of "early reply" mechanism for
            lock callbacks too... */
-        timeout = timeout + (timeout >> 1); /* 150% */
+        timeout = min_t(int, at_max, timeout + (timeout >> 1)); /* 150% */
         return max(timeout, ldlm_enqueue_min);
 }
 EXPORT_SYMBOL(ldlm_get_enq_timeout);
@@ -136,12 +138,13 @@ static int ldlm_completion_tail(struct ldlm_lock *lock)
                 result = -EIO;
         } else {
                 delay = cfs_time_sub(cfs_time_current_sec(),
-                                     lock->l_enqueued_time.tv_sec);
+                                     lock->l_last_activity);
                 LDLM_DEBUG(lock, "client-side enqueue: granted after "
                            CFS_DURATION_T"s", delay);
 
                 /* Update our time estimate */
-                at_add(&lock->l_resource->lr_namespace->ns_at_estimate, delay);
+                at_measured(ldlm_lock_to_ns_at(lock),
+                            delay);
                 result = 0;
         }
         return result;
@@ -247,12 +250,12 @@ noreproc:
         }
 
         if (imp != NULL) {
-                spin_lock(&imp->imp_lock);
+                cfs_spin_lock(&imp->imp_lock);
                 lwd.lwd_conn_cnt = imp->imp_conn_cnt;
-                spin_unlock(&imp->imp_lock);
+                cfs_spin_unlock(&imp->imp_lock);
         }
 
-        if (ns_is_client(lock->l_resource->lr_namespace) &&
+        if (ns_is_client(ldlm_lock_to_ns(lock)) &&
             OBD_FAIL_CHECK_RESET(OBD_FAIL_LDLM_INTR_CP_AST,
                                  OBD_FAIL_LDLM_CP_BL_RACE | OBD_FAIL_ONCE)) {
                 lock->l_flags |= LDLM_FL_FAIL_LOC;
@@ -334,7 +337,7 @@ int ldlm_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
         lock_res_and_lock(lock);
         /* Get this: if ldlm_blocking_ast is racing with intent_policy, such
          * that ldlm_blocking_ast is called just before intent_policy method
-         * takes the ns_lock, then by the time we get the lock, we might not
+         * takes the lr_lock, then by the time we get the lock, we might not
          * be the correct blocking function anymore.  So check, and return
          * early, if so. */
         if (lock->l_blocking_ast != ldlm_blocking_ast) {
@@ -378,7 +381,7 @@ int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
                            ldlm_blocking_callback blocking,
                            ldlm_completion_callback completion,
                            ldlm_glimpse_callback glimpse,
-                           void *data, __u32 lvb_len, void *lvb_swabber,
+                           void *data, __u32 lvb_len,
                            const __u64 *client_cookie,
                            struct lustre_handle *lockh)
 {
@@ -399,16 +402,16 @@ int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
         lock = ldlm_lock_create(ns, res_id, type, mode, &cbs, data, lvb_len);
         if (unlikely(!lock))
                 GOTO(out_nolock, err = -ENOMEM);
-        LDLM_DEBUG(lock, "client-side local enqueue handler, new lock created");
 
-        ldlm_lock_addref_internal(lock, mode);
         ldlm_lock2handle(lock, lockh);
-        lock_res_and_lock(lock);
+
+        /* NB: we don't have any lock now (lock_res_and_lock)
+         * because it's a new lock */
+        ldlm_lock_addref_internal_nolock(lock, mode);
         lock->l_flags |= LDLM_FL_LOCAL;
         if (*flags & LDLM_FL_ATOMIC_CB)
                 lock->l_flags |= LDLM_FL_ATOMIC_CB;
-        lock->l_lvb_swabber = lvb_swabber;
-        unlock_res_and_lock(lock);
+
         if (policy != NULL)
                 lock->l_policy_data = *policy;
         if (client_cookie != NULL)
@@ -423,13 +426,10 @@ int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
         if (policy != NULL)
                 *policy = lock->l_policy_data;
 
-        LDLM_DEBUG_NOLOCK("client-side local enqueue handler END (lock %p)",
-                          lock);
-
         if (lock->l_completion_ast)
                 lock->l_completion_ast(lock, *flags, NULL);
 
-        LDLM_DEBUG(lock, "client-side local enqueue END");
+        LDLM_DEBUG(lock, "client-side local enqueue handler, new lock created");
         EXIT;
  out:
         LDLM_LOCK_RELEASE(lock);
@@ -438,8 +438,7 @@ int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
 }
 
 static void failed_lock_cleanup(struct ldlm_namespace *ns,
-                                struct ldlm_lock *lock,
-                                struct lustre_handle *lockh, int mode)
+                                struct ldlm_lock *lock, int mode)
 {
         int need_cancel = 0;
 
@@ -452,38 +451,44 @@ static void failed_lock_cleanup(struct ldlm_namespace *ns,
                  * bl_ast and -EINVAL reply is sent to server anyways.
                  * bug 17645 */
                 lock->l_flags |= LDLM_FL_LOCAL_ONLY | LDLM_FL_FAILED |
-                                 LDLM_FL_ATOMIC_CB;
+                                 LDLM_FL_ATOMIC_CB | LDLM_FL_CBPENDING;
                 need_cancel = 1;
         }
         unlock_res_and_lock(lock);
 
-        if (need_cancel) {
+        if (need_cancel)
                 LDLM_DEBUG(lock,
                            "setting FL_LOCAL_ONLY | LDLM_FL_FAILED | "
-                           "LDLM_FL_ATOMIC_CB");
-                ldlm_lock_decref_and_cancel(lockh, mode);
-        } else {
+                           "LDLM_FL_ATOMIC_CB | LDLM_FL_CBPENDING");
+        else
                 LDLM_DEBUG(lock, "lock was granted or failed in race");
-                ldlm_lock_decref(lockh, mode);
-        }
+
+        ldlm_lock_decref_internal(lock, mode);
 
         /* XXX - HACK because we shouldn't call ldlm_lock_destroy()
          *       from llite/file.c/ll_file_flock(). */
+        /* This code makes for the fact that we do not have blocking handler on
+         * a client for flock locks. As such this is the place where we must
+         * completely kill failed locks. (interrupted and those that
+         * were waiting to be granted when server evicted us. */
         if (lock->l_resource->lr_type == LDLM_FLOCK) {
-                ldlm_lock_destroy(lock);
+                lock_res_and_lock(lock);
+                ldlm_resource_unlink_lock(lock);
+                ldlm_lock_destroy_nolock(lock);
+                unlock_res_and_lock(lock);
         }
 }
 
 int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
                           ldlm_type_t type, __u8 with_policy, ldlm_mode_t mode,
                           int *flags, void *lvb, __u32 lvb_len,
-                          void *lvb_swabber, struct lustre_handle *lockh,int rc)
+                          struct lustre_handle *lockh,int rc)
 {
         struct ldlm_namespace *ns = exp->exp_obd->obd_namespace;
         int is_replay = *flags & LDLM_FL_REPLAY;
-        struct lustre_handle old_hash_key;
         struct ldlm_lock *lock;
         struct ldlm_reply *reply;
+        struct ost_lvb *tmplvb;
         int cleanup_phase = 1;
         ENTRY;
 
@@ -505,14 +510,12 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
                         if (reply == NULL)
                                 rc = -EPROTO;
                         if (lvb_len) {
-                                struct ost_lvb *tmplvb;
 
                                 req_capsule_set_size(&req->rq_pill,
                                                      &RMF_DLM_LVB, RCL_SERVER,
                                                      lvb_len);
-                            tmplvb = req_capsule_server_swab_get(&req->rq_pill,
-                                                                 &RMF_DLM_LVB,
-                                                                 lvb_swabber);
+                                tmplvb = req_capsule_server_get(&req->rq_pill,
+                                                                 &RMF_DLM_LVB);
                                 if (tmplvb == NULL)
                                         GOTO(cleanup, rc = -EPROTO);
                                 if (lvb != NULL)
@@ -530,14 +533,15 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
         cleanup_phase = 0;
 
         lock_res_and_lock(lock);
-        old_hash_key = lock->l_remote_handle;
-        lock->l_remote_handle = reply->lock_handle;
-
         /* Key change rehash lock in per-export hash with new key */
-        if (exp->exp_lock_hash)
-                lustre_hash_rehash_key(exp->exp_lock_hash, &old_hash_key,
-                                       &lock->l_remote_handle,
-                                       &lock->l_exp_hash);
+        if (exp->exp_lock_hash) {
+                cfs_hash_rehash_key(exp->exp_lock_hash,
+                                    &lock->l_remote_handle,
+                                    &reply->lock_handle,
+                                    &lock->l_exp_hash);
+        } else {
+                lock->l_remote_handle = reply->lock_handle;
+        }
 
         *flags = reply->lock_flags;
         lock->l_flags |= reply->lock_flags & LDLM_INHERIT_FLAGS;
@@ -602,17 +606,25 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
 
         /* If the lock has already been granted by a completion AST, don't
          * clobber the LVB with an older one. */
-        if (lvb_len && (lock->l_req_mode != lock->l_granted_mode)) {
-                void *tmplvb;
+        if (lvb_len) {
+                /* We must lock or a racing completion might update lvb
+                   without letting us know and we'll clobber the correct value.
+                   Cannot unlock after the check either, a that still leaves
+                   a tiny window for completion to get in */
+                lock_res_and_lock(lock);
+                if (lock->l_req_mode != lock->l_granted_mode) {
 
-                req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
-                                     lvb_len);
-                tmplvb = req_capsule_server_swab_get(&req->rq_pill,
-                                                     &RMF_DLM_LVB,
-                                                     lvb_swabber);
-                if (tmplvb == NULL)
-                        GOTO(cleanup, rc = -EPROTO);
-                memcpy(lock->l_lvb_data, tmplvb, lvb_len);
+                        req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB,
+                                             RCL_SERVER, lvb_len);
+                        tmplvb = req_capsule_server_get(&req->rq_pill,
+                                                             &RMF_DLM_LVB);
+                        if (tmplvb == NULL) {
+                                unlock_res_and_lock(lock);
+                                GOTO(cleanup, rc = -EPROTO);
+                        }
+                        memcpy(lock->l_lvb_data, tmplvb, lvb_len);
+                }
+                unlock_res_and_lock(lock);
         }
 
         if (!is_replay) {
@@ -621,7 +633,7 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
                         int err = lock->l_completion_ast(lock, *flags, NULL);
                         if (!rc)
                                 rc = err;
-                        if (rc && type != LDLM_FLOCK) /* bug 9425, bug 10250 */
+                        if (rc)
                                 cleanup_phase = 1;
                 }
         }
@@ -636,7 +648,7 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
         EXIT;
 cleanup:
         if (cleanup_phase == 1 && rc)
-                failed_lock_cleanup(ns, lock, lockh, mode);
+                failed_lock_cleanup(ns, lock, mode);
         /* Put lock 2 times, the second reference is held by ldlm_cli_enqueue */
         LDLM_LOCK_PUT(lock);
         LDLM_LOCK_RELEASE(lock);
@@ -680,7 +692,7 @@ static inline int ldlm_format_handles_avail(struct obd_import *imp,
  * @count locks in @cancels. */
 int ldlm_prep_elc_req(struct obd_export *exp, struct ptlrpc_request *req,
                       int version, int opc, int canceloff,
-                      struct list_head *cancels, int count)
+                      cfs_list_t *cancels, int count)
 {
         struct ldlm_namespace   *ns = exp->exp_obd->obd_namespace;
         struct req_capsule      *pill = &req->rq_pill;
@@ -743,7 +755,7 @@ int ldlm_prep_elc_req(struct obd_export *exp, struct ptlrpc_request *req,
 }
 
 int ldlm_prep_enqueue_req(struct obd_export *exp, struct ptlrpc_request *req,
-                          struct list_head *cancels, int count)
+                          cfs_list_t *cancels, int count)
 {
         return ldlm_prep_elc_req(exp, req, LUSTRE_DLM_VERSION, LDLM_ENQUEUE,
                                  LDLM_ENQUEUE_CANCEL_OFF, cancels, count);
@@ -758,9 +770,9 @@ int ldlm_prep_enqueue_req(struct obd_export *exp, struct ptlrpc_request *req,
 int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
                      struct ldlm_enqueue_info *einfo,
                      const struct ldlm_res_id *res_id,
-                     ldlm_policy_data_t *policy, int *flags,
-                     void *lvb, __u32 lvb_len, void *lvb_swabber,
-                     struct lustre_handle *lockh, int async)
+                     ldlm_policy_data_t const *policy, int *flags,
+                     void *lvb, __u32 lvb_len, struct lustre_handle *lockh,
+                     int async)
 {
         struct ldlm_namespace *ns = exp->exp_obd->obd_namespace;
         struct ldlm_lock      *lock;
@@ -795,7 +807,6 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
                 /* for the local lock, add the reference */
                 ldlm_lock_addref_internal(lock, einfo->ei_mode);
                 ldlm_lock2handle(lock, lockh);
-                lock->l_lvb_swabber = lvb_swabber;
                 if (policy != NULL) {
                         /* INODEBITS_INTEROP: If the server does not support
                          * inodebits, we will request a plain lock in the
@@ -824,7 +835,7 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
                                                 LUSTRE_DLM_VERSION,
                                                 LDLM_ENQUEUE);
                 if (req == NULL) {
-                        failed_lock_cleanup(ns, lock, lockh, einfo->ei_mode);
+                        failed_lock_cleanup(ns, lock, einfo->ei_mode);
                         LDLM_LOCK_RELEASE(lock);
                         RETURN(-ENOMEM);
                 }
@@ -881,7 +892,7 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
 
         err = ldlm_cli_enqueue_fini(exp, req, einfo->ei_type, policy ? 1 : 0,
                                     einfo->ei_mode, flags, lvb, lvb_len,
-                                    lvb_swabber, lockh, rc);
+                                    lockh, rc);
 
         /* If ldlm_cli_enqueue_fini did not find the lock, we need to free
          * one reference that we took */
@@ -905,7 +916,7 @@ static int ldlm_cli_convert_local(struct ldlm_lock *lock, int new_mode,
         struct ldlm_resource *res;
         int rc;
         ENTRY;
-        if (ns_is_client(lock->l_resource->lr_namespace)) {
+        if (ns_is_client(ldlm_lock_to_ns(lock))) {
                 CERROR("Trying to cancel local lock\n");
                 LBUG();
         }
@@ -1028,14 +1039,13 @@ static int ldlm_cli_cancel_local(struct ldlm_lock *lock)
                 }
                 ldlm_lock_cancel(lock);
         } else {
-                if (ns_is_client(lock->l_resource->lr_namespace)) {
+                if (ns_is_client(ldlm_lock_to_ns(lock))) {
                         LDLM_ERROR(lock, "Trying to cancel local lock");
                         LBUG();
                 }
                 LDLM_DEBUG(lock, "server-side local cancel");
                 ldlm_lock_cancel(lock);
                 ldlm_reprocess_all(lock->l_resource);
-                LDLM_DEBUG(lock, "server-side local cancel handler END");
         }
 
         RETURN(rc);
@@ -1044,7 +1054,7 @@ static int ldlm_cli_cancel_local(struct ldlm_lock *lock)
 /* Pack @count locks in @head into ldlm_request buffer at the offset @off,
    of the request @req. */
 static void ldlm_cancel_pack(struct ptlrpc_request *req,
-                             struct list_head *head, int count)
+                             cfs_list_t *head, int count)
 {
         struct ldlm_request *dlm;
         struct ldlm_lock *lock;
@@ -1064,7 +1074,7 @@ static void ldlm_cancel_pack(struct ptlrpc_request *req,
         /* XXX: it would be better to pack lock handles grouped by resource.
          * so that the server cancel would call filter_lvbo_update() less
          * frequently. */
-        list_for_each_entry(lock, head, l_bl_ast) {
+        cfs_list_for_each_entry(lock, head, l_bl_ast) {
                 if (!count--)
                         break;
                 LASSERT(lock->l_conn_export);
@@ -1079,8 +1089,8 @@ static void ldlm_cancel_pack(struct ptlrpc_request *req,
 
 /* Prepare and send a batched cancel rpc, it will include count lock handles
  * of locks given in @head. */
-int ldlm_cli_cancel_req(struct obd_export *exp, struct list_head *cancels,
-                        int count, int flags)
+int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
+                        int count, ldlm_cancel_flags_t flags)
 {
         struct ptlrpc_request *req = NULL;
         struct obd_import *imp;
@@ -1134,7 +1144,7 @@ int ldlm_cli_cancel_req(struct obd_export *exp, struct list_head *cancels,
                 ldlm_cancel_pack(req, cancels, count);
 
                 ptlrpc_request_set_replen(req);
-                if (flags & LDLM_FL_ASYNC) {
+                if (flags & LCF_ASYNC) {
                         ptlrpcd_add_req(req, PSCOPE_OTHER);
                         sent = count;
                         GOTO(out, 0);
@@ -1217,11 +1227,11 @@ int ldlm_cli_update_pool(struct ptlrpc_request *req)
          * alive in cleanup time. Evil races are possible which may cause
          * oops in that time.
          */
-        write_lock(&obd->obd_pool_lock);
+        cfs_write_lock(&obd->obd_pool_lock);
         old_slv = obd->obd_pool_slv;
         obd->obd_pool_slv = new_slv;
         obd->obd_pool_limit = new_limit;
-        write_unlock(&obd->obd_pool_lock);
+        cfs_write_unlock(&obd->obd_pool_lock);
 
         RETURN(0);
 }
@@ -1251,8 +1261,8 @@ int ldlm_cli_cancel(struct lustre_handle *lockh)
         /* Even if the lock is marked as LDLM_FL_BL_AST, this is a LDLM_CANCEL
          * rpc which goes to canceld portal, so we can cancel other lru locks
          * here and send them all as one LDLM_CANCEL rpc. */
-        LASSERT(list_empty(&lock->l_bl_ast));
-        list_add(&lock->l_bl_ast, &cancels);
+        LASSERT(cfs_list_empty(&lock->l_bl_ast));
+        cfs_list_add(&lock->l_bl_ast, &cancels);
 
         exp = lock->l_conn_export;
         if (exp_connect_cancelset(exp)) {
@@ -1261,11 +1271,11 @@ int ldlm_cli_cancel(struct lustre_handle *lockh)
                                                   RCL_CLIENT, 0);
                 LASSERT(avail > 0);
 
-                ns = lock->l_resource->lr_namespace;
+                ns = ldlm_lock_to_ns(lock);
                 flags = ns_connect_lru_resize(ns) ?
                         LDLM_CANCEL_LRUR : LDLM_CANCEL_AGED;
                 count += ldlm_cancel_lru_local(ns, &cancels, 0, avail - 1,
-                                               LDLM_FL_BL_AST, flags);
+                                               LCF_BL_AST, flags);
         }
         ldlm_cli_cancel_list(&cancels, count, NULL, 0);
         RETURN(0);
@@ -1273,33 +1283,34 @@ int ldlm_cli_cancel(struct lustre_handle *lockh)
 
 /* XXX until we will have compound requests and can cut cancels from generic rpc
  * we need send cancels with LDLM_FL_BL_AST flag as separate rpc */
-static int ldlm_cancel_list(struct list_head *cancels, int count, int flags)
+int ldlm_cli_cancel_list_local(cfs_list_t *cancels, int count,
+                               ldlm_cancel_flags_t flags)
 {
         CFS_LIST_HEAD(head);
         struct ldlm_lock *lock, *next;
         int left = 0, bl_ast = 0, rc;
 
         left = count;
-        list_for_each_entry_safe(lock, next, cancels, l_bl_ast) {
+        cfs_list_for_each_entry_safe(lock, next, cancels, l_bl_ast) {
                 if (left-- == 0)
                         break;
 
-                if (flags & LDLM_FL_LOCAL_ONLY) {
+                if (flags & LCF_LOCAL) {
                         rc = LDLM_FL_LOCAL_ONLY;
                         ldlm_lock_cancel(lock);
                 } else {
                         rc = ldlm_cli_cancel_local(lock);
                 }
-                if (!(flags & LDLM_FL_BL_AST) && (rc == LDLM_FL_BL_AST)) {
+                if (!(flags & LCF_BL_AST) && (rc == LDLM_FL_BL_AST)) {
                         LDLM_DEBUG(lock, "Cancel lock separately");
-                        list_del_init(&lock->l_bl_ast);
-                        list_add(&lock->l_bl_ast, &head);
+                        cfs_list_del_init(&lock->l_bl_ast);
+                        cfs_list_add(&lock->l_bl_ast, &head);
                         bl_ast ++;
                         continue;
                 }
                 if (rc == LDLM_FL_LOCAL_ONLY) {
                         /* CANCEL RPC should not be sent to server. */
-                        list_del_init(&lock->l_bl_ast);
+                        cfs_list_del_init(&lock->l_bl_ast);
                         LDLM_LOCK_RELEASE(lock);
                         count--;
                 }
@@ -1314,62 +1325,34 @@ static int ldlm_cancel_list(struct list_head *cancels, int count, int flags)
 }
 
 /**
- * Callback function for shrink policy. Makes decision whether to keep
- * \a lock in LRU for current \a LRU size \a unused, added in current scan
- * \a added and number of locks to be preferably canceled \a count.
- *
- * \retval LDLM_POLICY_KEEP_LOCK keep lock in LRU in stop scanning
- *
- * \retval LDLM_POLICY_CANCEL_LOCK cancel lock from LRU
+ * Cancel as many locks as possible w/o sending any rpcs (e.g. to write back
+ * dirty data, to close a file, ...) or waiting for any rpcs in-flight (e.g.
+ * readahead requests, ...)
  */
-static ldlm_policy_res_t ldlm_cancel_shrink_policy(struct ldlm_namespace *ns,
-                                                   struct ldlm_lock *lock,
-                                                   int unused, int added,
-                                                   int count)
+static ldlm_policy_res_t ldlm_cancel_no_wait_policy(struct ldlm_namespace *ns,
+                                                    struct ldlm_lock *lock,
+                                                    int unused, int added,
+                                                    int count)
 {
-        int lock_cost;
-        __u64 page_nr;
-
-        /*
-         * Stop lru processing when we reached passed @count or checked all
-         * locks in lru.
-         */
-        if (count && added >= count)
-                return LDLM_POLICY_KEEP_LOCK;
-
-        if (lock->l_resource->lr_type == LDLM_EXTENT) {
-                if (lock->l_weigh_ast) {
-                        /*
-                         * For liblustre, l_weigh_ast should return 0 since it
-                         * don't cache pages
-                         */
-                        page_nr = lock->l_weigh_ast(lock);
-                } else {
-                        struct ldlm_extent *l_extent;
+        ldlm_policy_res_t result = LDLM_POLICY_CANCEL_LOCK;
+        ldlm_cancel_for_recovery cb = ns->ns_cancel_for_recovery;
+        lock_res_and_lock(lock);
 
-                        /*
-                         * For all extent locks cost is 1 + number of pages in
-                         * their extent.
-                         */
-                        l_extent = &lock->l_policy_data.l_extent;
-                        page_nr = l_extent->end - l_extent->start;
-                        do_div(page_nr, CFS_PAGE_SIZE);
-                }
-                lock_cost = 1 + page_nr;
-        } else {
-                /*
-                 * For all locks which are not extent ones cost is 1
-                 */
-                lock_cost = 1;
+        /* don't check added & count since we want to process all locks
+         * from unused list */
+        switch (lock->l_resource->lr_type) {
+                case LDLM_EXTENT:
+                case LDLM_IBITS:
+                        if (cb && cb(lock))
+                                break;
+                default:
+                        result = LDLM_POLICY_SKIP_LOCK;
+                        lock->l_flags |= LDLM_FL_SKIPPED;
+                        break;
         }
 
-        /*
-         * Keep all expensive locks in lru for the memory pressure time
-         * cancel policy. They anyways may be canceled by lru resize
-         * pplicy if they have not small enough CLV.
-         */
-        return lock_cost > ns->ns_shrink_thumb ?
-                LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
+        unlock_res_and_lock(lock);
+        RETURN(result);
 }
 
 /**
@@ -1413,7 +1396,7 @@ static ldlm_policy_res_t ldlm_cancel_lrur_policy(struct ldlm_namespace *ns,
          * Inform pool about current CLV to see it via proc.
          */
         ldlm_pool_set_clv(pl, lv);
-        return (slv == 1 || lv < slv) ?
+        return (slv == 0 || lv < slv) ?
                 LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
 }
 
@@ -1493,9 +1476,13 @@ typedef ldlm_policy_res_t (*ldlm_cancel_lru_policy_t)(struct ldlm_namespace *,
 static ldlm_cancel_lru_policy_t
 ldlm_cancel_lru_policy(struct ldlm_namespace *ns, int flags)
 {
+        if (flags & LDLM_CANCEL_NO_WAIT)
+                return ldlm_cancel_no_wait_policy;
+
         if (ns_connect_lru_resize(ns)) {
                 if (flags & LDLM_CANCEL_SHRINK)
-                        return ldlm_cancel_shrink_policy;
+                        /* We kill passed number of old locks. */
+                        return ldlm_cancel_passed_policy;
                 else if (flags & LDLM_CANCEL_LRUR)
                         return ldlm_cancel_lrur_policy;
                 else if (flags & LDLM_CANCEL_PASSED)
@@ -1533,17 +1520,23 @@ ldlm_cancel_lru_policy(struct ldlm_namespace *ns, int flags)
  *                              memory pressre policy function;
  *
  * flags & LDLM_CANCEL_AGED -   cancel alocks according to "aged policy".
+ *
+ * flags & LDLM_CANCEL_NO_WAIT - cancel as many unused locks as possible
+ *                               (typically before replaying locks) w/o
+ *                               sending any rpcs or waiting for any
+ *                               outstanding rpc to complete.
  */
-int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
-                          int count, int max, int cancel_flags, int flags)
+static int ldlm_prepare_lru_list(struct ldlm_namespace *ns, cfs_list_t *cancels,
+                                 int count, int max, int flags)
 {
         ldlm_cancel_lru_policy_t pf;
         struct ldlm_lock *lock, *next;
-        int added = 0, unused;
+        int added = 0, unused, remained;
         ENTRY;
 
-        spin_lock(&ns->ns_unused_lock);
+        cfs_spin_lock(&ns->ns_lock);
         unused = ns->ns_nr_unused;
+        remained = unused;
 
         if (!ns_connect_lru_resize(ns))
                 count += unused - ns->ns_max_unused;
@@ -1551,15 +1544,27 @@ int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
         pf = ldlm_cancel_lru_policy(ns, flags);
         LASSERT(pf != NULL);
 
-        while (!list_empty(&ns->ns_unused_list)) {
+        while (!cfs_list_empty(&ns->ns_unused_list)) {
+                ldlm_policy_res_t result;
+
+                /* all unused locks */
+                if (remained-- <= 0)
+                        break;
+
                 /* For any flags, stop scanning if @max is reached. */
                 if (max && added >= max)
                         break;
 
-                list_for_each_entry_safe(lock, next, &ns->ns_unused_list, l_lru){
+                cfs_list_for_each_entry_safe(lock, next, &ns->ns_unused_list,
+                                             l_lru){
                         /* No locks which got blocking requests. */
                         LASSERT(!(lock->l_flags & LDLM_FL_BL_AST));
 
+                        if (flags & LDLM_CANCEL_NO_WAIT &&
+                            lock->l_flags & LDLM_FL_SKIPPED)
+                                /* already processed */
+                                continue;
+
                         /* Somebody is already doing CANCEL. No need in this
                          * lock in lru, do not traverse it again. */
                         if (!(lock->l_flags & LDLM_FL_CANCELING))
@@ -1571,7 +1576,7 @@ int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
                         break;
 
                 LDLM_LOCK_GET(lock);
-                spin_unlock(&ns->ns_unused_lock);
+                cfs_spin_unlock(&ns->ns_lock);
                 lu_ref_add(&lock->l_reference, __FUNCTION__, cfs_current());
 
                 /* Pass the lock through the policy filter and see if it
@@ -1587,14 +1592,21 @@ int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
                  * old locks, but additionally chose them by
                  * their weight. Big extent locks will stay in
                  * the cache. */
-                if (pf(ns, lock, unused, added, count) ==
-                    LDLM_POLICY_KEEP_LOCK) {
+                result = pf(ns, lock, unused, added, count);
+                if (result == LDLM_POLICY_KEEP_LOCK) {
                         lu_ref_del(&lock->l_reference,
                                    __FUNCTION__, cfs_current());
                         LDLM_LOCK_RELEASE(lock);
-                        spin_lock(&ns->ns_unused_lock);
+                        cfs_spin_lock(&ns->ns_lock);
                         break;
                 }
+                if (result == LDLM_POLICY_SKIP_LOCK) {
+                        lu_ref_del(&lock->l_reference,
+                                   __FUNCTION__, cfs_current());
+                        LDLM_LOCK_RELEASE(lock);
+                        cfs_spin_lock(&ns->ns_lock);
+                        continue;
+                }
 
                 lock_res_and_lock(lock);
                 /* Check flags again under the lock. */
@@ -1609,7 +1621,7 @@ int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
                         lu_ref_del(&lock->l_reference,
                                    __FUNCTION__, cfs_current());
                         LDLM_LOCK_RELEASE(lock);
-                        spin_lock(&ns->ns_unused_lock);
+                        cfs_spin_lock(&ns->ns_lock);
                         continue;
                 }
                 LASSERT(!lock->l_readers && !lock->l_writers);
@@ -1631,82 +1643,38 @@ int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
 
                 /* We can't re-add to l_lru as it confuses the
                  * refcounting in ldlm_lock_remove_from_lru() if an AST
-                 * arrives after we drop ns_lock below. We use l_bl_ast
+                 * arrives after we drop lr_lock below. We use l_bl_ast
                  * and can't use l_pending_chain as it is used both on
                  * server and client nevertheless bug 5666 says it is
                  * used only on server */
-                LASSERT(list_empty(&lock->l_bl_ast));
-                list_add(&lock->l_bl_ast, cancels);
+                LASSERT(cfs_list_empty(&lock->l_bl_ast));
+                cfs_list_add(&lock->l_bl_ast, cancels);
                 unlock_res_and_lock(lock);
                 lu_ref_del(&lock->l_reference, __FUNCTION__, cfs_current());
-                spin_lock(&ns->ns_unused_lock);
+                cfs_spin_lock(&ns->ns_lock);
                 added++;
                 unused--;
         }
-        spin_unlock(&ns->ns_unused_lock);
-        RETURN(ldlm_cancel_list(cancels, added, cancel_flags));
+        cfs_spin_unlock(&ns->ns_lock);
+        RETURN(added);
 }
 
-/* Returns number of locks which could be canceled next time when
- * ldlm_cancel_lru() is called. Used from locks pool shrinker. */
-int ldlm_cancel_lru_estimate(struct ldlm_namespace *ns,
-                             int count, int max, int flags)
+int ldlm_cancel_lru_local(struct ldlm_namespace *ns, cfs_list_t *cancels,
+                          int count, int max, ldlm_cancel_flags_t cancel_flags,
+                          int flags)
 {
-        struct list_head disp = CFS_LIST_HEAD_INIT(disp);
-        ldlm_cancel_lru_policy_t pf;
-        struct ldlm_lock *lock;
-        int added = 0, unused;
-        int loop_stop = 0;
-        ENTRY;
-
-        pf = ldlm_cancel_lru_policy(ns, flags);
-        LASSERT(pf != NULL);
-        spin_lock(&ns->ns_unused_lock);
-        unused = ns->ns_nr_unused;
-        list_splice_init(&ns->ns_unused_list, &disp);
-        while (!list_empty(&disp)) {
-                lock = list_entry(disp.next, struct ldlm_lock, l_lru);
-                list_move_tail(&lock->l_lru, &ns->ns_unused_list);
-
-                /* For any flags, stop scanning if @max is reached. */
-                if (max && added >= max)
-                        break;
-
-                /* Somebody is already doing CANCEL or there is a
-                 * blocking request will send cancel. Let's not count
-                 * this lock. */
-                if ((lock->l_flags & LDLM_FL_CANCELING) ||
-                    (lock->l_flags & LDLM_FL_BL_AST))
-                        continue;
-
-                LDLM_LOCK_GET(lock);
-                spin_unlock(&ns->ns_unused_lock);
-                lu_ref_add(&lock->l_reference, __FUNCTION__, cfs_current());
-
-                /* Pass the lock through the policy filter and see if it
-                 * should stay in lru. */
-                if (pf(ns, lock, unused, added, count) == LDLM_POLICY_KEEP_LOCK)
-                        loop_stop = 1;
-
-                lu_ref_del(&lock->l_reference, __FUNCTION__, cfs_current());
-                LDLM_LOCK_RELEASE(lock);
-                spin_lock(&ns->ns_unused_lock);
-                if (loop_stop)
-                        break;
-
-                added++;
-                unused--;
-        }
-        list_splice(&disp, ns->ns_unused_list.prev);
-        spin_unlock(&ns->ns_unused_lock);
-        RETURN(added);
+        int added;
+        added = ldlm_prepare_lru_list(ns, cancels, count, max, flags);
+        if (added <= 0)
+                return added;
+        return ldlm_cli_cancel_list_local(cancels, added, cancel_flags);
 }
 
 /* when called with LDLM_ASYNC the blocking callback will be handled
  * in a thread and this function will return after the thread has been
  * asked to call the callback.  when called with LDLM_SYNC the blocking
  * callback will be performed in this function. */
-int ldlm_cancel_lru(struct ldlm_namespace *ns, int nr, ldlm_sync_t sync,
+int ldlm_cancel_lru(struct ldlm_namespace *ns, int nr, ldlm_sync_t mode,
                     int flags)
 {
         CFS_LIST_HEAD(cancels);
@@ -1714,36 +1682,33 @@ int ldlm_cancel_lru(struct ldlm_namespace *ns, int nr, ldlm_sync_t sync,
         ENTRY;
 
 #ifndef __KERNEL__
-        sync = LDLM_SYNC; /* force to be sync in user space */
+        mode = LDLM_SYNC; /* force to be sync in user space */
 #endif
-        count = ldlm_cancel_lru_local(ns, &cancels, nr, 0, 0, flags);
-        if (sync == LDLM_ASYNC) {
-                rc = ldlm_bl_to_thread_list(ns, NULL, &cancels, count);
-                if (rc == 0)
-                        RETURN(count);
-        }
+        /* Just prepare the list of locks, do not actually cancel them yet.
+         * Locks are cancelled later in a separate thread. */
+        count = ldlm_prepare_lru_list(ns, &cancels, nr, 0, flags);
+        rc = ldlm_bl_to_thread_list(ns, NULL, &cancels, count, mode);
+        if (rc == 0)
+                RETURN(count);
 
-        /* If an error occured in ASYNC mode, or
-         * this is SYNC mode, cancel the list. */
-        ldlm_cli_cancel_list(&cancels, count, NULL, 0);
-        RETURN(count);
+        RETURN(0);
 }
 
 /* Find and cancel locally unused locks found on resource, matched to the
  * given policy, mode. GET the found locks and add them into the @cancels
  * list. */
 int ldlm_cancel_resource_local(struct ldlm_resource *res,
-                               struct list_head *cancels,
+                               cfs_list_t *cancels,
                                ldlm_policy_data_t *policy,
                                ldlm_mode_t mode, int lock_flags,
-                               int cancel_flags, void *opaque)
+                               ldlm_cancel_flags_t cancel_flags, void *opaque)
 {
         struct ldlm_lock *lock;
         int count = 0;
         ENTRY;
 
         lock_res(res);
-        list_for_each_entry(lock, &res->lr_granted, l_res_link) {
+        cfs_list_for_each_entry(lock, &res->lr_granted, l_res_link) {
                 if (opaque != NULL && lock->l_ast_data != opaque) {
                         LDLM_ERROR(lock, "data %p doesn't match opaque %p",
                                    lock->l_ast_data, opaque);
@@ -1751,13 +1716,8 @@ int ldlm_cancel_resource_local(struct ldlm_resource *res,
                         continue;
                 }
 
-                if (lock->l_readers || lock->l_writers) {
-                        if (cancel_flags & LDLM_FL_WARN) {
-                                LDLM_ERROR(lock, "lock in use");
-                                //LBUG();
-                        }
+                if (lock->l_readers || lock->l_writers)
                         continue;
-                }
 
                 /* If somebody is already doing CANCEL, or blocking ast came,
                  * skip this lock. */
@@ -1779,14 +1739,14 @@ int ldlm_cancel_resource_local(struct ldlm_resource *res,
                 lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING |
                                  lock_flags;
 
-                LASSERT(list_empty(&lock->l_bl_ast));
-                list_add(&lock->l_bl_ast, cancels);
+                LASSERT(cfs_list_empty(&lock->l_bl_ast));
+                cfs_list_add(&lock->l_bl_ast, cancels);
                 LDLM_LOCK_GET(lock);
                 count++;
         }
         unlock_res(res);
 
-        RETURN(ldlm_cancel_list(cancels, count, cancel_flags));
+        RETURN(ldlm_cli_cancel_list_local(cancels, count, cancel_flags));
 }
 
 /* If @req is NULL, send CANCEL request to server with handles of locks
@@ -1795,14 +1755,14 @@ int ldlm_cancel_resource_local(struct ldlm_resource *res,
  * If @req is not NULL, put handles of locks in @cancels into the request
  * buffer at the offset @off.
  * Destroy @cancels at the end. */
-int ldlm_cli_cancel_list(struct list_head *cancels, int count,
-                         struct ptlrpc_request *req, int flags)
+int ldlm_cli_cancel_list(cfs_list_t *cancels, int count,
+                         struct ptlrpc_request *req, ldlm_cancel_flags_t flags)
 {
         struct ldlm_lock *lock;
         int res = 0;
         ENTRY;
 
-        if (list_empty(cancels) || count == 0)
+        if (cfs_list_empty(cancels) || count == 0)
                 RETURN(0);
 
         /* XXX: requests (both batched and not) could be sent in parallel.
@@ -1811,8 +1771,9 @@ int ldlm_cli_cancel_list(struct list_head *cancels, int count,
          * It would also speed up the case when the server does not support
          * the feature. */
         while (count > 0) {
-                LASSERT(!list_empty(cancels));
-                lock = list_entry(cancels->next, struct ldlm_lock, l_bl_ast);
+                LASSERT(!cfs_list_empty(cancels));
+                lock = cfs_list_entry(cancels->next, struct ldlm_lock,
+                                      l_bl_ast);
                 LASSERT(lock->l_conn_export);
 
                 if (exp_connect_cancelset(lock->l_conn_export)) {
@@ -1843,7 +1804,9 @@ int ldlm_cli_cancel_list(struct list_head *cancels, int count,
 int ldlm_cli_cancel_unused_resource(struct ldlm_namespace *ns,
                                     const struct ldlm_res_id *res_id,
                                     ldlm_policy_data_t *policy,
-                                    ldlm_mode_t mode, int flags, void *opaque)
+                                    ldlm_mode_t mode,
+                                    ldlm_cancel_flags_t flags,
+                                    void *opaque)
 {
         struct ldlm_resource *res;
         CFS_LIST_HEAD(cancels);
@@ -1860,7 +1823,7 @@ int ldlm_cli_cancel_unused_resource(struct ldlm_namespace *ns,
 
         LDLM_RESOURCE_ADDREF(res);
         count = ldlm_cancel_resource_local(res, &cancels, policy, mode,
-                                           0, flags, opaque);
+                                           0, flags | LCF_BL_AST, opaque);
         rc = ldlm_cli_cancel_list(&cancels, count, NULL, flags);
         if (rc != ELDLM_OK)
                 CERROR("ldlm_cli_cancel_unused_resource: %d\n", rc);
@@ -1870,68 +1833,57 @@ int ldlm_cli_cancel_unused_resource(struct ldlm_namespace *ns,
         RETURN(0);
 }
 
-static inline int have_no_nsresource(struct ldlm_namespace *ns)
-{
-        int no_resource = 0;
-
-        spin_lock(&ns->ns_hash_lock);
-        if (ns->ns_resources == 0)
-                no_resource = 1;
-        spin_unlock(&ns->ns_hash_lock);
+struct ldlm_cli_cancel_arg {
+        int     lc_flags;
+        void   *lc_opaque;
+};
 
-        RETURN(no_resource);
+static int ldlm_cli_hash_cancel_unused(cfs_hash_t *hs, cfs_hash_bd_t *bd,
+                                       cfs_hlist_node_t *hnode, void *arg)
+{
+        struct ldlm_resource           *res = cfs_hash_object(hs, hnode);
+        struct ldlm_cli_cancel_arg     *lc = arg;
+        int                             rc;
+
+        rc = ldlm_cli_cancel_unused_resource(ldlm_res_to_ns(res), &res->lr_name,
+                                             NULL, LCK_MINMODE,
+                                             lc->lc_flags, lc->lc_opaque);
+        if (rc != 0) {
+                CERROR("ldlm_cli_cancel_unused ("LPU64"): %d\n",
+                       res->lr_name.name[0], rc);
+        }
+        /* must return 0 for hash iteration */
+        return 0;
 }
 
 /* Cancel all locks on a namespace (or a specific resource, if given)
  * that have 0 readers/writers.
  *
- * If flags & LDLM_FL_LOCAL_ONLY, throw the locks away without trying
+ * If flags & LCF_LOCAL, throw the locks away without trying
  * to notify the server. */
 int ldlm_cli_cancel_unused(struct ldlm_namespace *ns,
                            const struct ldlm_res_id *res_id,
-                           int flags, void *opaque)
+                           ldlm_cancel_flags_t flags, void *opaque)
 {
-        int i;
+        struct ldlm_cli_cancel_arg arg = {
+                .lc_flags       = flags,
+                .lc_opaque      = opaque,
+        };
+
         ENTRY;
 
         if (ns == NULL)
                 RETURN(ELDLM_OK);
 
-        if (res_id)
+        if (res_id != NULL) {
                 RETURN(ldlm_cli_cancel_unused_resource(ns, res_id, NULL,
                                                        LCK_MINMODE, flags,
                                                        opaque));
-
-        spin_lock(&ns->ns_hash_lock);
-        for (i = 0; i < RES_HASH_SIZE; i++) {
-                struct list_head *tmp;
-                tmp = ns->ns_hash[i].next;
-                while (tmp != &(ns->ns_hash[i])) {
-                        struct ldlm_resource *res;
-                        int rc;
-
-                        res = list_entry(tmp, struct ldlm_resource, lr_hash);
-                        ldlm_resource_getref(res);
-                        spin_unlock(&ns->ns_hash_lock);
-
-                        LDLM_RESOURCE_ADDREF(res);
-                        rc = ldlm_cli_cancel_unused_resource(ns, &res->lr_name,
-                                                             NULL, LCK_MINMODE,
-                                                             flags, opaque);
-
-                        if (rc)
-                                CERROR("ldlm_cli_cancel_unused ("LPU64"): %d\n",
-                                       res->lr_name.name[0], rc);
-
-                        LDLM_RESOURCE_DELREF(res);
-                        spin_lock(&ns->ns_hash_lock);
-                        tmp = tmp->next;
-                        ldlm_resource_putref_locked(res);
-                }
+        } else {
+                cfs_hash_for_each_nolock(ns->ns_rs_hash,
+                                         ldlm_cli_hash_cancel_unused, &arg);
+                RETURN(ELDLM_OK);
         }
-        spin_unlock(&ns->ns_hash_lock);
-
-        RETURN(ELDLM_OK);
 }
 
 /* Lock iterators. */
@@ -1939,7 +1891,7 @@ int ldlm_cli_cancel_unused(struct ldlm_namespace *ns,
 int ldlm_resource_foreach(struct ldlm_resource *res, ldlm_iterator_t iter,
                           void *closure)
 {
-        struct list_head *tmp, *next;
+        cfs_list_t *tmp, *next;
         struct ldlm_lock *lock;
         int rc = LDLM_ITER_CONTINUE;
 
@@ -1949,22 +1901,22 @@ int ldlm_resource_foreach(struct ldlm_resource *res, ldlm_iterator_t iter,
                 RETURN(LDLM_ITER_CONTINUE);
 
         lock_res(res);
-        list_for_each_safe(tmp, next, &res->lr_granted) {
-                lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+        cfs_list_for_each_safe(tmp, next, &res->lr_granted) {
+                lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
 
                 if (iter(lock, closure) == LDLM_ITER_STOP)
                         GOTO(out, rc = LDLM_ITER_STOP);
         }
 
-        list_for_each_safe(tmp, next, &res->lr_converting) {
-                lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+        cfs_list_for_each_safe(tmp, next, &res->lr_converting) {
+                lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
 
                 if (iter(lock, closure) == LDLM_ITER_STOP)
                         GOTO(out, rc = LDLM_ITER_STOP);
         }
 
-        list_for_each_safe(tmp, next, &res->lr_waiting) {
-                lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+        cfs_list_for_each_safe(tmp, next, &res->lr_waiting) {
+                lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
 
                 if (iter(lock, closure) == LDLM_ITER_STOP)
                         GOTO(out, rc = LDLM_ITER_STOP);
@@ -1985,56 +1937,38 @@ static int ldlm_iter_helper(struct ldlm_lock *lock, void *closure)
         return helper->iter(lock, helper->closure);
 }
 
-static int ldlm_res_iter_helper(struct ldlm_resource *res, void *closure)
+static int ldlm_res_iter_helper(cfs_hash_t *hs, cfs_hash_bd_t *bd,
+                                cfs_hlist_node_t *hnode, void *arg)
+
 {
-        return ldlm_resource_foreach(res, ldlm_iter_helper, closure);
+        struct ldlm_resource *res = cfs_hash_object(hs, hnode);
+
+        return ldlm_resource_foreach(res, ldlm_iter_helper, arg) ==
+               LDLM_ITER_STOP;
 }
 
-int ldlm_namespace_foreach(struct ldlm_namespace *ns, ldlm_iterator_t iter,
-                           void *closure)
+void ldlm_namespace_foreach(struct ldlm_namespace *ns,
+                            ldlm_iterator_t iter, void *closure)
+
 {
         struct iter_helper_data helper = { iter: iter, closure: closure };
-        return ldlm_namespace_foreach_res(ns, ldlm_res_iter_helper, &helper);
-}
 
-int ldlm_namespace_foreach_res(struct ldlm_namespace *ns,
-                               ldlm_res_iterator_t iter, void *closure)
-{
-        int i, rc = LDLM_ITER_CONTINUE;
-        struct ldlm_resource *res;
-        struct list_head *tmp;
+        cfs_hash_for_each_nolock(ns->ns_rs_hash,
+                                 ldlm_res_iter_helper, &helper);
 
-        ENTRY;
-        spin_lock(&ns->ns_hash_lock);
-        for (i = 0; i < RES_HASH_SIZE; i++) {
-                tmp = ns->ns_hash[i].next;
-                while (tmp != &(ns->ns_hash[i])) {
-                        res = list_entry(tmp, struct ldlm_resource, lr_hash);
-                        ldlm_resource_getref(res);
-                        spin_unlock(&ns->ns_hash_lock);
-                        LDLM_RESOURCE_ADDREF(res);
-
-                        rc = iter(res, closure);
-
-                        LDLM_RESOURCE_DELREF(res);
-                        spin_lock(&ns->ns_hash_lock);
-                        tmp = tmp->next;
-                        ldlm_resource_putref_locked(res);
-                        if (rc == LDLM_ITER_STOP)
-                                GOTO(out, rc);
-                }
-        }
- out:
-        spin_unlock(&ns->ns_hash_lock);
-        RETURN(rc);
 }
 
-/* non-blocking function to manipulate a lock whose cb_data is being put away.*/
-void ldlm_resource_iterate(struct ldlm_namespace *ns,
-                           const struct ldlm_res_id *res_id,
-                           ldlm_iterator_t iter, void *data)
+/* non-blocking function to manipulate a lock whose cb_data is being put away.
+ * return  0:  find no resource
+ *       > 0:  must be LDLM_ITER_STOP/LDLM_ITER_CONTINUE.
+ *       < 0:  errors
+ */
+int ldlm_resource_iterate(struct ldlm_namespace *ns,
+                          const struct ldlm_res_id *res_id,
+                          ldlm_iterator_t iter, void *data)
 {
         struct ldlm_resource *res;
+        int rc;
         ENTRY;
 
         if (ns == NULL) {
@@ -2043,30 +1977,35 @@ void ldlm_resource_iterate(struct ldlm_namespace *ns,
         }
 
         res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
-        if (res == NULL) {
-                EXIT;
-                return;
-        }
+        if (res == NULL)
+                RETURN(0);
 
         LDLM_RESOURCE_ADDREF(res);
-        ldlm_resource_foreach(res, iter, data);
+        rc = ldlm_resource_foreach(res, iter, data);
         LDLM_RESOURCE_DELREF(res);
         ldlm_resource_putref(res);
-        EXIT;
+        RETURN(rc);
 }
 
 /* Lock replay */
 
 static int ldlm_chain_lock_for_replay(struct ldlm_lock *lock, void *closure)
 {
-        struct list_head *list = closure;
+        cfs_list_t *list = closure;
 
         /* we use l_pending_chain here, because it's unused on clients. */
-        LASSERTF(list_empty(&lock->l_pending_chain),"lock %p next %p prev %p\n",
+        LASSERTF(cfs_list_empty(&lock->l_pending_chain),
+                 "lock %p next %p prev %p\n",
                  lock, &lock->l_pending_chain.next,&lock->l_pending_chain.prev);
-        /* bug 9573: don't replay locks left after eviction */
-        if (!(lock->l_flags & LDLM_FL_FAILED))
-                list_add(&lock->l_pending_chain, list);
+        /* bug 9573: don't replay locks left after eviction, or
+         * bug 17614: locks being actively cancelled. Get a reference
+         * on a lock so that it does not disapear under us (e.g. due to cancel)
+         */
+        if (!(lock->l_flags & (LDLM_FL_FAILED|LDLM_FL_CANCELING))) {
+                cfs_list_add(&lock->l_pending_chain, list);
+                LDLM_LOCK_GET(lock);
+        }
+
         return LDLM_ITER_CONTINUE;
 }
 
@@ -2074,13 +2013,12 @@ static int replay_lock_interpret(const struct lu_env *env,
                                  struct ptlrpc_request *req,
                                  struct ldlm_async_args *aa, int rc)
 {
-        struct lustre_handle  old_hash_key;
         struct ldlm_lock     *lock;
         struct ldlm_reply    *reply;
         struct obd_export    *exp;
 
         ENTRY;
-        atomic_dec(&req->rq_import->imp_replay_inflight);
+        cfs_atomic_dec(&req->rq_import->imp_replay_inflight);
         if (rc != ELDLM_OK)
                 GOTO(out, rc);
 
@@ -2099,15 +2037,16 @@ static int replay_lock_interpret(const struct lu_env *env,
                 GOTO(out, rc = -ESTALE);
         }
 
-        old_hash_key = lock->l_remote_handle;
-        lock->l_remote_handle = reply->lock_handle;
-
         /* Key change rehash lock in per-export hash with new key */
-       exp = req->rq_export;
-        if (exp && exp->exp_lock_hash)
-                lustre_hash_rehash_key(exp->exp_lock_hash, &old_hash_key,
-                                      &lock->l_remote_handle,
-                                       &lock->l_exp_hash);
+        exp = req->rq_export;
+        if (exp && exp->exp_lock_hash) {
+                cfs_hash_rehash_key(exp->exp_lock_hash,
+                                    &lock->l_remote_handle,
+                                    &reply->lock_handle,
+                                    &lock->l_exp_hash);
+        } else {
+                lock->l_remote_handle = reply->lock_handle;
+        }
 
         LDLM_DEBUG(lock, "replayed lock:");
         ptlrpc_import_recovery_state_machine(req->rq_import);
@@ -2160,7 +2099,7 @@ static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
                 flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_GRANTED;
         else if (lock->l_granted_mode)
                 flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_CONV;
-        else if (!list_empty(&lock->l_res_link))
+        else if (!cfs_list_empty(&lock->l_res_link))
                 flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_WAIT;
         else
                 flags = LDLM_FL_REPLAY;
@@ -2192,7 +2131,7 @@ static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
 
         LDLM_DEBUG(lock, "replaying lock:");
 
-        atomic_inc(&req->rq_import->imp_replay_inflight);
+        cfs_atomic_inc(&req->rq_import->imp_replay_inflight);
         CLASSERT(sizeof(*aa) <= sizeof(req->rq_async_args));
         aa = ptlrpc_req_async_args(req);
         aa->lock_handle = body->lock_handle[0];
@@ -2202,6 +2141,35 @@ static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
         RETURN(0);
 }
 
+/**
+ * Cancel as many unused locks as possible before replay. since we are
+ * in recovery, we can't wait for any outstanding RPCs to send any RPC
+ * to the server.
+ *
+ * Called only in recovery before replaying locks. there is no need to
+ * replay locks that are unused. since the clients may hold thousands of
+ * cached unused locks, dropping the unused locks can greatly reduce the
+ * load on the servers at recovery time.
+ */
+static void ldlm_cancel_unused_locks_for_replay(struct ldlm_namespace *ns)
+{
+        int canceled;
+        CFS_LIST_HEAD(cancels);
+
+        CDEBUG(D_DLMTRACE, "Dropping as many unused locks as possible before"
+                           "replay for namespace %s (%d)\n",
+                           ldlm_ns_name(ns), ns->ns_nr_unused);
+
+        /* We don't need to care whether or not LRU resize is enabled
+         * because the LDLM_CANCEL_NO_WAIT policy doesn't use the
+         * count parameter */
+        canceled = ldlm_cancel_lru_local(ns, &cancels, ns->ns_nr_unused, 0,
+                                         LCF_LOCAL, LDLM_CANCEL_NO_WAIT);
+
+        CDEBUG(D_DLMTRACE, "Canceled %d unused locks from namespace %s\n",
+                           canceled, ldlm_ns_name(ns));
+}
+
 int ldlm_replay_locks(struct obd_import *imp)
 {
         struct ldlm_namespace *ns = imp->imp_obd->obd_namespace;
@@ -2211,21 +2179,31 @@ int ldlm_replay_locks(struct obd_import *imp)
 
         ENTRY;
 
-        LASSERT(atomic_read(&imp->imp_replay_inflight) == 0);
+        LASSERT(cfs_atomic_read(&imp->imp_replay_inflight) == 0);
+
+        /* don't replay locks if import failed recovery */
+        if (imp->imp_vbr_failed)
+                RETURN(0);
 
         /* ensure this doesn't fall to 0 before all have been queued */
-        atomic_inc(&imp->imp_replay_inflight);
+        cfs_atomic_inc(&imp->imp_replay_inflight);
 
-        (void)ldlm_namespace_foreach(ns, ldlm_chain_lock_for_replay, &list);
+        if (ldlm_cancel_unused_locks_before_replay)
+                ldlm_cancel_unused_locks_for_replay(ns);
 
-        list_for_each_entry_safe(lock, next, &list, l_pending_chain) {
-                list_del_init(&lock->l_pending_chain);
-                if (rc)
+        ldlm_namespace_foreach(ns, ldlm_chain_lock_for_replay, &list);
+
+        cfs_list_for_each_entry_safe(lock, next, &list, l_pending_chain) {
+                cfs_list_del_init(&lock->l_pending_chain);
+                if (rc) {
+                        LDLM_LOCK_RELEASE(lock);
                         continue; /* or try to do the rest? */
+                }
                 rc = replay_one_lock(imp, lock);
+                LDLM_LOCK_RELEASE(lock);
         }
 
-        atomic_dec(&imp->imp_replay_inflight);
+        cfs_atomic_dec(&imp->imp_replay_inflight);
 
         RETURN(rc);
 }