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LU-6529 ldlm: cancel aged locks for LRUR
[fs/lustre-release.git] / lustre / ldlm / ldlm_request.c
index 13e3a6d..684062f 100644 (file)
@@ -1,6 +1,4 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 /*
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2010, 2014, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  */
+/**
+ * This file contains Asynchronous System Trap (AST) handlers and related
+ * LDLM request-processing routines.
+ *
+ * An AST is a callback issued on a lock when its state is changed. There are
+ * several different types of ASTs (callbacks) registered for each lock:
+ *
+ * - completion AST: when a lock is enqueued by some process, but cannot be
+ *   granted immediately due to other conflicting locks on the same resource,
+ *   the completion AST is sent to notify the caller when the lock is
+ *   eventually granted
+ *
+ * - blocking AST: when a lock is granted to some process, if another process
+ *   enqueues a conflicting (blocking) lock on a resource, a blocking AST is
+ *   sent to notify the holder(s) of the lock(s) of the conflicting lock
+ *   request. The lock holder(s) must release their lock(s) on that resource in
+ *   a timely manner or be evicted by the server.
+ *
+ * - glimpse AST: this is used when a process wants information about a lock
+ *   (i.e. the lock value block (LVB)) but does not necessarily require holding
+ *   the lock. If the resource is locked, the lock holder(s) are sent glimpse
+ *   ASTs and the LVB is returned to the caller, and lock holder(s) may CANCEL
+ *   their lock(s) if they are idle. If the resource is not locked, the server
+ *   may grant the lock.
+ */
 
 #define DEBUG_SUBSYSTEM S_LDLM
-#ifndef __KERNEL__
-#include <signal.h>
-#include <liblustre.h>
-#endif
 
 #include <lustre_dlm.h>
 #include <obd_class.h>
 
 #include "ldlm_internal.h"
 
-int ldlm_enqueue_min = OBD_TIMEOUT_DEFAULT;
-CFS_MODULE_PARM(ldlm_enqueue_min, "i", int, 0644,
+unsigned int ldlm_enqueue_min = OBD_TIMEOUT_DEFAULT;
+CFS_MODULE_PARM(ldlm_enqueue_min, "i", uint, 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)
 {
 }
@@ -74,20 +98,22 @@ int ldlm_expired_completion_wait(void *data)
         if (lock->l_conn_export == NULL) {
                 static cfs_time_t next_dump = 0, last_dump = 0;
 
-                if (ptlrpc_check_suspend())
-                        RETURN(0);
-
-                LDLM_ERROR(lock, "lock timed out (enqueued at "CFS_TIME_T", "
-                           CFS_DURATION_T"s ago); not entering recovery in "
-                           "server code, just going back to sleep",
-                           lock->l_last_activity,
-                           cfs_time_sub(cfs_time_current_sec(),
-                           lock->l_last_activity));
+               LCONSOLE_WARN("lock timed out (enqueued at "CFS_TIME_T", "
+                             CFS_DURATION_T"s ago)\n",
+                             lock->l_last_activity,
+                             cfs_time_sub(cfs_time_current_sec(),
+                                          lock->l_last_activity));
+               LDLM_DEBUG(lock, "lock timed out (enqueued at "CFS_TIME_T", "
+                          CFS_DURATION_T"s ago); not entering recovery in "
+                          "server code, just going back to sleep",
+                          lock->l_last_activity,
+                          cfs_time_sub(cfs_time_current_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();
                 }
@@ -106,45 +132,57 @@ int ldlm_expired_completion_wait(void *data)
         RETURN(0);
 }
 
+/**
+ * Calculate the Completion timeout (covering enqueue, BL AST, data flush,
+ * lock cancel, and their replies). Used for lock completion timeout on the
+ * client side.
+ *
+ * \param[in] lock        lock which is waiting the completion callback
+ *
+ * \retval            timeout in seconds to wait for the server reply
+ */
+
 /* We use the same basis for both server side and client side functions
    from a single node. */
-int ldlm_get_enq_timeout(struct ldlm_lock *lock)
+static unsigned int ldlm_cp_timeout(struct ldlm_lock *lock)
 {
-        int timeout = at_get(&lock->l_resource->lr_namespace->ns_at_estimate);
-        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 = min_t(int, at_max, timeout + (timeout >> 1)); /* 150% */
-        return max(timeout, ldlm_enqueue_min);
+       unsigned int timeout;
+
+       if (AT_OFF)
+               return obd_timeout;
+
+       /* Wait a long time for enqueue - server may have to callback a
+        * lock from another client.  Server will evict the other client if it
+        * doesn't respond reasonably, and then give us the lock. */
+       timeout = at_get(ldlm_lock_to_ns_at(lock));
+       return max(3 * timeout, ldlm_enqueue_min);
 }
-EXPORT_SYMBOL(ldlm_get_enq_timeout);
 
 /**
  * Helper function for ldlm_completion_ast(), updating timings when lock is
  * actually granted.
  */
-static int ldlm_completion_tail(struct ldlm_lock *lock)
+static int ldlm_completion_tail(struct ldlm_lock *lock, void *data)
 {
-        long delay;
-        int  result;
-
-        if (lock->l_destroyed || lock->l_flags & LDLM_FL_FAILED) {
-                LDLM_DEBUG(lock, "client-side enqueue: destroyed");
-                result = -EIO;
-        } else {
-                delay = cfs_time_sub(cfs_time_current_sec(),
-                                     lock->l_last_activity);
-                LDLM_DEBUG(lock, "client-side enqueue: granted after "
-                           CFS_DURATION_T"s", delay);
-
-                /* Update our time estimate */
-                at_measured(&lock->l_resource->lr_namespace->ns_at_estimate,
-                            delay);
-                result = 0;
-        }
-        return result;
+       long delay;
+       int  result = 0;
+
+       if (ldlm_is_destroyed(lock) || ldlm_is_failed(lock)) {
+               LDLM_DEBUG(lock, "client-side enqueue: destroyed");
+               result = -EIO;
+       } else if (data == NULL) {
+               LDLM_DEBUG(lock, "client-side enqueue: granted");
+       } else {
+               /* Take into AT only CP RPC, not immediately granted locks */
+               delay = cfs_time_sub(cfs_time_current_sec(),
+                                    lock->l_last_activity);
+               LDLM_DEBUG(lock, "client-side enqueue: granted after "
+                          CFS_DURATION_T"s", delay);
+
+               /* Update our time estimate */
+               at_measured(ldlm_lock_to_ns_at(lock), delay);
+       }
+       return result;
 }
 
 /**
@@ -152,36 +190,35 @@ static int ldlm_completion_tail(struct ldlm_lock *lock)
  * until lock is granted. Suitable for locks enqueued through ptlrpcd, of
  * other threads that cannot block for long.
  */
-int ldlm_completion_ast_async(struct ldlm_lock *lock, int flags, void *data)
+int ldlm_completion_ast_async(struct ldlm_lock *lock, __u64 flags, void *data)
 {
-        ENTRY;
-
-        if (flags == LDLM_FL_WAIT_NOREPROC) {
-                LDLM_DEBUG(lock, "client-side enqueue waiting on pending lock");
-                RETURN(0);
-        }
-
-        if (!(flags & (LDLM_FL_BLOCK_WAIT | LDLM_FL_BLOCK_GRANTED |
-                       LDLM_FL_BLOCK_CONV))) {
-                cfs_waitq_signal(&lock->l_waitq);
-                RETURN(ldlm_completion_tail(lock));
-        }
-
-        LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
-                   "going forward");
-        ldlm_lock_dump(D_OTHER, lock, 0);
-        ldlm_reprocess_all(lock->l_resource);
-        RETURN(0);
+       ENTRY;
+
+       if (flags == LDLM_FL_WAIT_NOREPROC) {
+               LDLM_DEBUG(lock, "client-side enqueue waiting on pending lock");
+               RETURN(0);
+       }
+
+       if (!(flags & LDLM_FL_BLOCKED_MASK)) {
+               wake_up(&lock->l_waitq);
+               RETURN(ldlm_completion_tail(lock, data));
+       }
+
+       LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
+                  "going forward");
+       ldlm_reprocess_all(lock->l_resource);
+       RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_completion_ast_async);
 
 /**
- * Client side LDLM "completion" AST. This is called in several cases:
+ * Generic LDLM "completion" AST. This is called in several cases:
  *
- *     - when a reply to an ENQUEUE rpc is received from the server
+ *     - when a reply to an ENQUEUE RPC is received from the server
  *       (ldlm_cli_enqueue_fini()). Lock might be granted or not granted at
  *       this point (determined by flags);
  *
- *     - when LDLM_CP_CALLBACK rpc comes to client to notify it that lock has
+ *     - when LDLM_CP_CALLBACK RPC comes to client to notify it that lock has
  *       been granted;
  *
  *     - when ldlm_lock_match(LDLM_FL_LVB_READY) is about to wait until lock
@@ -195,7 +232,7 @@ int ldlm_completion_ast_async(struct ldlm_lock *lock, int flags, void *data)
  * or penultimate cases happen in some other thread.
  *
  */
-int ldlm_completion_ast(struct ldlm_lock *lock, int flags, void *data)
+int ldlm_completion_ast(struct ldlm_lock *lock, __u64 flags, void *data)
 {
         /* XXX ALLOCATE - 160 bytes */
         struct lock_wait_data lwd;
@@ -211,15 +248,13 @@ int ldlm_completion_ast(struct ldlm_lock *lock, int flags, void *data)
                 goto noreproc;
         }
 
-        if (!(flags & (LDLM_FL_BLOCK_WAIT | LDLM_FL_BLOCK_GRANTED |
-                       LDLM_FL_BLOCK_CONV))) {
-                cfs_waitq_signal(&lock->l_waitq);
-                RETURN(0);
-        }
+       if (!(flags & LDLM_FL_BLOCKED_MASK)) {
+               wake_up(&lock->l_waitq);
+               RETURN(0);
+       }
 
         LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
                    "sleeping");
-        ldlm_lock_dump(D_OTHER, lock, 0);
 
 noreproc:
 
@@ -230,14 +265,12 @@ noreproc:
                 imp = obd->u.cli.cl_import;
         }
 
-        /* Wait a long time for enqueue - server may have to callback a
-           lock from another client.  Server will evict the other client if it
-           doesn't respond reasonably, and then give us the lock. */
-        timeout = ldlm_get_enq_timeout(lock) * 2;
+       timeout = ldlm_cp_timeout(lock);
 
-        lwd.lwd_lock = lock;
+       lwd.lwd_lock = lock;
+       lock->l_last_activity = cfs_time_current_sec();
 
-        if (lock->l_flags & LDLM_FL_NO_TIMEOUT) {
+       if (ldlm_is_no_timeout(lock)) {
                 LDLM_DEBUG(lock, "waiting indefinitely because of NO_TIMEOUT");
                 lwi = LWI_INTR(interrupted_completion_wait, &lwd);
         } else {
@@ -246,16 +279,16 @@ noreproc:
                                        interrupted_completion_wait, &lwd);
         }
 
-        if (imp != NULL) {
-                cfs_spin_lock(&imp->imp_lock);
-                lwd.lwd_conn_cnt = imp->imp_conn_cnt;
-                cfs_spin_unlock(&imp->imp_lock);
-        }
+       if (imp != NULL) {
+               spin_lock(&imp->imp_lock);
+               lwd.lwd_conn_cnt = imp->imp_conn_cnt;
+               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;
+               ldlm_set_fail_loc(lock);
                 rc = -EINTR;
         } else {
                 /* Go to sleep until the lock is granted or cancelled. */
@@ -267,18 +300,19 @@ noreproc:
                 LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
                            rc);
                 RETURN(rc);
-        }
+       }
 
-        RETURN(ldlm_completion_tail(lock));
+       RETURN(ldlm_completion_tail(lock, data));
 }
+EXPORT_SYMBOL(ldlm_completion_ast);
 
 /**
- * A helper to build a blocking ast function
+ * A helper to build a blocking AST function
  *
- * Perform a common operation for blocking asts:
+ * Perform a common operation for blocking ASTs:
  * defferred lock cancellation.
  *
- * \param lock the lock blocking or canceling ast was called on
+ * \param lock the lock blocking or canceling AST was called on
  * \retval 0
  * \see mdt_blocking_ast
  * \see ldlm_blocking_ast
@@ -288,7 +322,7 @@ int ldlm_blocking_ast_nocheck(struct ldlm_lock *lock)
         int do_ast;
         ENTRY;
 
-        lock->l_flags |= LDLM_FL_CBPENDING;
+       ldlm_set_cbpending(lock);
         do_ast = (!lock->l_readers && !lock->l_writers);
         unlock_res_and_lock(lock);
 
@@ -298,7 +332,7 @@ int ldlm_blocking_ast_nocheck(struct ldlm_lock *lock)
 
                 LDLM_DEBUG(lock, "already unused, calling ldlm_cli_cancel");
                 ldlm_lock2handle(lock, &lockh);
-                rc = ldlm_cli_cancel(&lockh);
+               rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
                 if (rc < 0)
                         CERROR("ldlm_cli_cancel: %d\n", rc);
         } else {
@@ -307,6 +341,7 @@ int ldlm_blocking_ast_nocheck(struct ldlm_lock *lock)
         }
         RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_blocking_ast_nocheck);
 
 /**
  * Server blocking AST
@@ -334,7 +369,7 @@ 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) {
@@ -343,42 +378,53 @@ int ldlm_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
         }
         RETURN(ldlm_blocking_ast_nocheck(lock));
 }
+EXPORT_SYMBOL(ldlm_blocking_ast);
 
-/*
- * ->l_glimpse_ast() for DLM extent locks acquired on the server-side. See
- * comment in filter_intent_policy() on why you may need this.
+/**
+ * Implements ldlm_lock::l_glimpse_ast for extent locks acquired on the server.
+ *
+ * Returning -ELDLM_NO_LOCK_DATA actually works, but the reason for that is
+ * rather subtle: with OST-side locking, it may so happen that _all_ extent
+ * locks are held by the OST. If client wants to obtain the current file size
+ * it calls ll_glimpse_size(), and (as all locks are held only on the server),
+ * this dummy glimpse callback fires and does nothing. The client still
+ * receives the correct file size due to the following fragment of code in
+ * ldlm_cb_interpret():
+ *
+ *     if (rc == -ELDLM_NO_LOCK_DATA) {
+ *             LDLM_DEBUG(lock, "lost race - client has a lock but no"
+ *                        "inode");
+ *             ldlm_res_lvbo_update(lock->l_resource, NULL, 1);
+ *     }
+ *
+ * That is, after the glimpse returns this error, ofd_lvbo_update() is called
+ * and returns the updated file attributes from the inode to the client.
+ *
+ * See also comment in ofd_intent_policy() on why servers must set a non-NULL
+ * l_glimpse_ast when grabbing DLM locks.  Otherwise, the server will assume
+ * that the object is in the process of being destroyed.
+ *
+ * \param[in] lock     DLM lock being glimpsed, unused
+ * \param[in] reqp     pointer to ptlrpc_request, unused
+ *
+ * \retval             -ELDLM_NO_LOCK_DATA to get attributes from disk object
  */
 int ldlm_glimpse_ast(struct ldlm_lock *lock, void *reqp)
 {
-        /*
-         * Returning -ELDLM_NO_LOCK_DATA actually works, but the reason for
-         * that is rather subtle: with OST-side locking, it may so happen that
-         * _all_ extent locks are held by the OST. If client wants to obtain
-         * current file size it calls ll{,u}_glimpse_size(), and (as locks are
-         * on the server), dummy glimpse callback fires and does
-         * nothing. Client still receives correct file size due to the
-         * following fragment in filter_intent_policy():
-         *
-         * rc = l->l_glimpse_ast(l, NULL); // this will update the LVB
-         * if (rc != 0 && res->lr_namespace->ns_lvbo &&
-         *     res->lr_namespace->ns_lvbo->lvbo_update) {
-         *         res->lr_namespace->ns_lvbo->lvbo_update(res, NULL, 0, 1);
-         * }
-         *
-         * that is, after glimpse_ast() fails, filter_lvbo_update() runs, and
-         * returns correct file size to the client.
-         */
         return -ELDLM_NO_LOCK_DATA;
 }
 
+/**
+ * Enqueue a local lock (typically on a server).
+ */
 int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
                            const struct ldlm_res_id *res_id,
                            ldlm_type_t type, ldlm_policy_data_t *policy,
-                           ldlm_mode_t mode, int *flags,
+                          ldlm_mode_t mode, __u64 *flags,
                            ldlm_blocking_callback blocking,
                            ldlm_completion_callback completion,
                            ldlm_glimpse_callback glimpse,
-                           void *data, __u32 lvb_len,
+                          void *data, __u32 lvb_len, enum lvb_type lvb_type,
                            const __u64 *client_cookie,
                            struct lustre_handle *lockh)
 {
@@ -396,23 +442,37 @@ int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
                 LBUG();
         }
 
-        lock = ldlm_lock_create(ns, res_id, type, mode, &cbs, data, lvb_len);
-        if (unlikely(!lock))
-                GOTO(out_nolock, err = -ENOMEM);
+       lock = ldlm_lock_create(ns, res_id, type, mode, &cbs, data, lvb_len,
+                               lvb_type);
+       if (IS_ERR(lock))
+               GOTO(out_nolock, err = PTR_ERR(lock));
+
+       err = ldlm_lvbo_init(lock->l_resource);
+       if (err < 0) {
+               LDLM_ERROR(lock, "delayed lvb init failed (rc %d)", err);
+               GOTO(out, err);
+       }
 
-        ldlm_lock_addref_internal(lock, mode);
         ldlm_lock2handle(lock, lockh);
-        lock_res_and_lock(lock);
-        lock->l_flags |= LDLM_FL_LOCAL;
+
+        /* 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);
+       ldlm_set_local(lock);
         if (*flags & LDLM_FL_ATOMIC_CB)
-                lock->l_flags |= LDLM_FL_ATOMIC_CB;
-        unlock_res_and_lock(lock);
+               ldlm_set_atomic_cb(lock);
+
         if (policy != NULL)
                 lock->l_policy_data = *policy;
         if (client_cookie != NULL)
                 lock->l_client_cookie = *client_cookie;
-        if (type == LDLM_EXTENT)
-                lock->l_req_extent = policy->l_extent;
+       if (type == LDLM_EXTENT) {
+               /* extent lock without policy is a bug */
+               if (policy == NULL)
+                       LBUG();
+
+               lock->l_req_extent = policy->l_extent;
+       }
 
         err = ldlm_lock_enqueue(ns, &lock, policy, flags);
         if (unlikely(err != ELDLM_OK))
@@ -431,6 +491,7 @@ int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
  out_nolock:
         return err;
 }
+EXPORT_SYMBOL(ldlm_cli_enqueue_local);
 
 static void failed_lock_cleanup(struct ldlm_namespace *ns,
                                 struct ldlm_lock *lock, int mode)
@@ -441,13 +502,13 @@ static void failed_lock_cleanup(struct ldlm_namespace *ns,
         lock_res_and_lock(lock);
         /* Check that lock is not granted or failed, we might race. */
         if ((lock->l_req_mode != lock->l_granted_mode) &&
-            !(lock->l_flags & LDLM_FL_FAILED)) {
-                /* Make sure that this lock will not be found by raced
-                 * 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_CBPENDING;
-                need_cancel = 1;
+           !ldlm_is_failed(lock)) {
+               /* Make sure that this lock will not be found by raced
+                * bl_ast and -EINVAL reply is sent to server anyways.
+                * b=17645*/
+               lock->l_flags |= LDLM_FL_LOCAL_ONLY | LDLM_FL_FAILED |
+                                LDLM_FL_ATOMIC_CB | LDLM_FL_CBPENDING;
+               need_cancel = 1;
         }
         unlock_res_and_lock(lock);
 
@@ -458,30 +519,37 @@ static void failed_lock_cleanup(struct ldlm_namespace *ns,
         else
                 LDLM_DEBUG(lock, "lock was granted or failed in race");
 
-        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) {
-                lock_res_and_lock(lock);
-                ldlm_resource_unlink_lock(lock);
-                ldlm_lock_destroy_nolock(lock);
-                unlock_res_and_lock(lock);
-        }
+       /* 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) {
+               lock_res_and_lock(lock);
+               if (!ldlm_is_destroyed(lock)) {
+                       ldlm_resource_unlink_lock(lock);
+                       ldlm_lock_decref_internal_nolock(lock, mode);
+                       ldlm_lock_destroy_nolock(lock);
+               }
+               unlock_res_and_lock(lock);
+       } else {
+               ldlm_lock_decref_internal(lock, mode);
+       }
 }
 
+/**
+ * Finishing portion of client lock enqueue code.
+ *
+ * Called after receiving reply from server.
+ */
 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,
+                         __u64 *flags, void *lvb, __u32 lvb_len,
                           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;
         int cleanup_phase = 1;
@@ -494,123 +562,132 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
                 RETURN(-ENOLCK);
         }
 
+       LASSERTF(ergo(lvb_len != 0, lvb_len == lock->l_lvb_len),
+                "lvb_len = %d, l_lvb_len = %d\n", lvb_len, lock->l_lvb_len);
+
         if (rc != ELDLM_OK) {
                 LASSERT(!is_replay);
                 LDLM_DEBUG(lock, "client-side enqueue END (%s)",
                            rc == ELDLM_LOCK_ABORTED ? "ABORTED" : "FAILED");
-                if (rc == ELDLM_LOCK_ABORTED) {
-                        /* Before we return, swab the reply */
-                        reply = req_capsule_server_get(&req->rq_pill,
-                                                       &RMF_DLM_REP);
-                        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_get(&req->rq_pill,
-                                                                 &RMF_DLM_LVB);
-                                if (tmplvb == NULL)
-                                        GOTO(cleanup, rc = -EPROTO);
-                                if (lvb != NULL)
-                                        memcpy(lvb, tmplvb, lvb_len);
-                        }
-                }
-                GOTO(cleanup, rc);
-        }
 
-        reply = req_capsule_server_get(&req->rq_pill, &RMF_DLM_REP);
-        if (reply == NULL)
-                GOTO(cleanup, rc = -EPROTO);
+               if (rc != ELDLM_LOCK_ABORTED)
+                       GOTO(cleanup, rc);
+       }
+
+       /* Before we return, swab the reply */
+       reply = req_capsule_server_get(&req->rq_pill, &RMF_DLM_REP);
+       if (reply == NULL)
+               GOTO(cleanup, rc = -EPROTO);
+
+       if (lvb_len > 0) {
+               int size = 0;
+
+               size = req_capsule_get_size(&req->rq_pill, &RMF_DLM_LVB,
+                                           RCL_SERVER);
+               if (size < 0) {
+                       LDLM_ERROR(lock, "Fail to get lvb_len, rc = %d", size);
+                       GOTO(cleanup, rc = size);
+               } else if (unlikely(size > lvb_len)) {
+                       LDLM_ERROR(lock, "Replied LVB is larger than "
+                                  "expectation, expected = %d, replied = %d",
+                                  lvb_len, size);
+                       GOTO(cleanup, rc = -EINVAL);
+               }
+               lvb_len = size;
+       }
+
+       if (rc == ELDLM_LOCK_ABORTED) {
+               if (lvb_len > 0 && lvb != NULL)
+                       rc = ldlm_fill_lvb(lock, &req->rq_pill, RCL_SERVER,
+                                          lvb, lvb_len);
+               GOTO(cleanup, rc = rc ? : ELDLM_LOCK_ABORTED);
+       }
 
         /* lock enqueued on the server */
         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)
-                cfs_hash_rehash_key(exp->exp_lock_hash, &old_hash_key,
+        if (exp->exp_lock_hash) {
+               /* In the function below, .hs_keycmp resolves to
+                * ldlm_export_lock_keycmp() */
+               /* coverity[overrun-buffer-val] */
+                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;
-        /* move NO_TIMEOUT flag to the lock to force ldlm_lock_match()
-         * to wait with no timeout as well */
-        lock->l_flags |= reply->lock_flags & LDLM_FL_NO_TIMEOUT;
+       *flags = ldlm_flags_from_wire(reply->lock_flags);
+       lock->l_flags |= ldlm_flags_from_wire(reply->lock_flags &
+                                             LDLM_FL_INHERIT_MASK);
         unlock_res_and_lock(lock);
 
-        CDEBUG(D_INFO, "local: %p, remote cookie: "LPX64", flags: 0x%x\n",
-               lock, reply->lock_handle.cookie, *flags);
-
-        /* If enqueue returned a blocked lock but the completion handler has
-         * already run, then it fixed up the resource and we don't need to do it
-         * again. */
-        if ((*flags) & LDLM_FL_LOCK_CHANGED) {
-                int newmode = reply->lock_desc.l_req_mode;
-                LASSERT(!is_replay);
-                if (newmode && newmode != lock->l_req_mode) {
-                        LDLM_DEBUG(lock, "server returned different mode %s",
-                                   ldlm_lockname[newmode]);
-                        lock->l_req_mode = newmode;
-                }
-
-                if (memcmp(reply->lock_desc.l_resource.lr_name.name,
-                          lock->l_resource->lr_name.name,
-                          sizeof(struct ldlm_res_id))) {
-                        CDEBUG(D_INFO, "remote intent success, locking "
-                                        "(%ld,%ld,%ld) instead of "
-                                        "(%ld,%ld,%ld)\n",
-                              (long)reply->lock_desc.l_resource.lr_name.name[0],
-                              (long)reply->lock_desc.l_resource.lr_name.name[1],
-                              (long)reply->lock_desc.l_resource.lr_name.name[2],
-                              (long)lock->l_resource->lr_name.name[0],
-                              (long)lock->l_resource->lr_name.name[1],
-                              (long)lock->l_resource->lr_name.name[2]);
-
-                        rc = ldlm_lock_change_resource(ns, lock,
-                                        &reply->lock_desc.l_resource.lr_name);
-                        if (rc || lock->l_resource == NULL)
-                                GOTO(cleanup, rc = -ENOMEM);
-                        LDLM_DEBUG(lock, "client-side enqueue, new resource");
-                }
-                if (with_policy)
-                        if (!(type == LDLM_IBITS && !(exp->exp_connect_flags &
-                                                    OBD_CONNECT_IBITS)))
-                                lock->l_policy_data =
-                                                 reply->lock_desc.l_policy_data;
+       CDEBUG(D_INFO, "local: %p, remote cookie: "LPX64", flags: "LPX64"\n",
+              lock, reply->lock_handle.cookie, *flags);
+
+       /* If enqueue returned a blocked lock but the completion handler has
+        * already run, then it fixed up the resource and we don't need to do it
+        * again. */
+       if ((*flags) & LDLM_FL_LOCK_CHANGED) {
+               int newmode = reply->lock_desc.l_req_mode;
+               LASSERT(!is_replay);
+               if (newmode && newmode != lock->l_req_mode) {
+                       LDLM_DEBUG(lock, "server returned different mode %s",
+                                  ldlm_lockname[newmode]);
+                       lock->l_req_mode = newmode;
+               }
+
+               if (!ldlm_res_eq(&reply->lock_desc.l_resource.lr_name,
+                                &lock->l_resource->lr_name)) {
+                       CDEBUG(D_INFO, "remote intent success, locking "DLDLMRES
+                                      " instead of "DLDLMRES"\n",
+                              PLDLMRES(&reply->lock_desc.l_resource),
+                              PLDLMRES(lock->l_resource));
+
+                       rc = ldlm_lock_change_resource(ns, lock,
+                                       &reply->lock_desc.l_resource.lr_name);
+                       if (rc || lock->l_resource == NULL)
+                               GOTO(cleanup, rc = -ENOMEM);
+                       LDLM_DEBUG(lock, "client-side enqueue, new resource");
+               }
+               if (with_policy)
+                       if (!(type == LDLM_IBITS &&
+                             !(exp_connect_flags(exp) & OBD_CONNECT_IBITS)))
+                               /* We assume lock type cannot change on server*/
+                               ldlm_convert_policy_to_local(exp,
+                                               lock->l_resource->lr_type,
+                                               &reply->lock_desc.l_policy_data,
+                                               &lock->l_policy_data);
                 if (type != LDLM_PLAIN)
                         LDLM_DEBUG(lock,"client-side enqueue, new policy data");
         }
 
-        if ((*flags) & LDLM_FL_AST_SENT ||
-            /* Cancel extent locks as soon as possible on a liblustre client,
-             * because it cannot handle asynchronous ASTs robustly (see
-             * bug 7311). */
-            (LIBLUSTRE_CLIENT && type == LDLM_EXTENT)) {
+       if ((*flags) & LDLM_FL_AST_SENT) {
                 lock_res_and_lock(lock);
-                lock->l_flags |= LDLM_FL_CBPENDING |  LDLM_FL_BL_AST;
+               lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_BL_AST;
                 unlock_res_and_lock(lock);
                 LDLM_DEBUG(lock, "enqueue reply includes blocking AST");
         }
 
         /* 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;
-
-                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)
-                        GOTO(cleanup, rc = -EPROTO);
-                memcpy(lock->l_lvb_data, tmplvb, lvb_len);
+       if (lvb_len > 0) {
+               /* 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)
+                       rc = ldlm_fill_lvb(lock, &req->rq_pill, RCL_SERVER,
+                                          lock->l_lvb_data, lvb_len);
+               unlock_res_and_lock(lock);
+               if (rc < 0) {
+                       cleanup_phase = 1;
+                       GOTO(cleanup, rc);
+               }
         }
 
         if (!is_replay) {
@@ -624,11 +701,11 @@ int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
                 }
         }
 
-        if (lvb_len && lvb != NULL) {
-                /* Copy the LVB here, and not earlier, because the completion
-                 * AST (if any) can override what we got in the reply */
-                memcpy(lvb, lock->l_lvb_data, lvb_len);
-        }
+       if (lvb_len > 0 && lvb != NULL) {
+               /* Copy the LVB here, and not earlier, because the completion
+                * AST (if any) can override what we got in the reply */
+               memcpy(lvb, lock->l_lvb_data, lvb_len);
+       }
 
         LDLM_DEBUG(lock, "client-side enqueue END");
         EXIT;
@@ -640,15 +717,19 @@ cleanup:
         LDLM_LOCK_RELEASE(lock);
         return rc;
 }
+EXPORT_SYMBOL(ldlm_cli_enqueue_fini);
 
-/* PAGE_SIZE-512 is to allow TCP/IP and LNET headers to fit into
- * a single page on the send/receive side. XXX: 512 should be changed
- * to more adequate value. */
+/**
+ * Estimate number of lock handles that would fit into request of given
+ * size.  PAGE_SIZE-512 is to allow TCP/IP and LNET headers to fit into
+ * a single page on the send/receive side. XXX: 512 should be changed to
+ * more adequate value.
+ */
 static inline int ldlm_req_handles_avail(int req_size, int off)
 {
         int avail;
 
-        avail = min_t(int, LDLM_MAXREQSIZE, CFS_PAGE_SIZE - 512) - req_size;
+       avail = min_t(int, LDLM_MAXREQSIZE, PAGE_CACHE_SIZE - 512) - req_size;
         if (likely(avail >= 0))
                 avail /= (int)sizeof(struct lustre_handle);
         else
@@ -662,37 +743,43 @@ static inline int ldlm_capsule_handles_avail(struct req_capsule *pill,
                                              enum req_location loc,
                                              int off)
 {
-        int size = req_capsule_msg_size(pill, loc);
-        return ldlm_req_handles_avail(size, off);
+       __u32 size = req_capsule_msg_size(pill, loc);
+       return ldlm_req_handles_avail(size, off);
 }
 
 static inline int ldlm_format_handles_avail(struct obd_import *imp,
                                             const struct req_format *fmt,
                                             enum req_location loc, int off)
 {
-        int size = req_capsule_fmt_size(imp->imp_msg_magic, fmt, loc);
-        return ldlm_req_handles_avail(size, off);
+       __u32 size = req_capsule_fmt_size(imp->imp_msg_magic, fmt, loc);
+       return ldlm_req_handles_avail(size, off);
 }
 
-/* Cancel lru locks and pack them into the enqueue request. Pack there the given
- * @count locks in @cancels. */
+/**
+ * Cancel LRU locks and pack them into the enqueue request. Pack there the given
+ * \a count locks in \a cancels.
+ *
+ * This is to be called by functions preparing their own requests that
+ * might contain lists of locks to cancel in addition to actual operation
+ * that needs to be performed.
+ */
 int ldlm_prep_elc_req(struct obd_export *exp, struct ptlrpc_request *req,
-                      int version, int opc, int canceloff,
-                      cfs_list_t *cancels, int count)
-{
-        struct ldlm_namespace   *ns = exp->exp_obd->obd_namespace;
-        struct req_capsule      *pill = &req->rq_pill;
-        struct ldlm_request     *dlm = NULL;
-        int flags, avail, to_free, bufcount, pack = 0;
-        CFS_LIST_HEAD(head);
-        int rc;
-        ENTRY;
-
-        if (cancels == NULL)
-                cancels = &head;
-        if (exp_connect_cancelset(exp)) {
+                     int version, int opc, int canceloff,
+                     struct list_head *cancels, int count)
+       {
+       struct ldlm_namespace   *ns = exp->exp_obd->obd_namespace;
+       struct req_capsule      *pill = &req->rq_pill;
+       struct ldlm_request     *dlm = NULL;
+       struct list_head        head = LIST_HEAD_INIT(head);
+       int flags, avail, to_free, pack = 0;
+       int rc;
+       ENTRY;
+
+       if (cancels == NULL)
+               cancels = &head;
+       if (ns_connect_cancelset(ns)) {
                 /* Estimate the amount of available space in the request. */
-                bufcount = req_capsule_filled_sizes(pill, RCL_CLIENT);
+                req_capsule_filled_sizes(pill, RCL_CLIENT);
                 avail = ldlm_capsule_handles_avail(pill, RCL_CLIENT, canceloff);
 
                 flags = ns_connect_lru_resize(ns) ?
@@ -700,9 +787,9 @@ int ldlm_prep_elc_req(struct obd_export *exp, struct ptlrpc_request *req,
                 to_free = !ns_connect_lru_resize(ns) &&
                           opc == LDLM_ENQUEUE ? 1 : 0;
 
-                /* Cancel lru locks here _only_ if the server supports
-                 * EARLY_CANCEL. Otherwise we have to send extra CANCEL
-                 * rpc, what will make us slower. */
+               /* Cancel LRU locks here _only_ if the server supports
+                * EARLY_CANCEL. Otherwise we have to send extra CANCEL
+                * RPC, which will make us slower. */
                 if (avail > count)
                         count += ldlm_cancel_lru_local(ns, cancels, to_free,
                                                        avail - count, 0, flags);
@@ -720,47 +807,75 @@ int ldlm_prep_elc_req(struct obd_export *exp, struct ptlrpc_request *req,
                 RETURN(rc);
         }
 
-        if (exp_connect_cancelset(exp)) {
+       if (ns_connect_cancelset(ns)) {
                 if (canceloff) {
                         dlm = req_capsule_client_get(pill, &RMF_DLM_REQ);
                         LASSERT(dlm);
                         /* Skip first lock handler in ldlm_request_pack(),
-                         * this method will incrment @lock_count according
+                        * this method will increment @lock_count according
                          * to the lock handle amount actually written to
                          * the buffer. */
                         dlm->lock_count = canceloff;
                 }
                 /* Pack into the request @pack lock handles. */
                 ldlm_cli_cancel_list(cancels, pack, req, 0);
-                /* Prepare and send separate cancel rpc for others. */
+               /* Prepare and send separate cancel RPC for others. */
                 ldlm_cli_cancel_list(cancels, count - pack, NULL, 0);
         } else {
                 ldlm_lock_list_put(cancels, l_bl_ast, count);
         }
         RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_prep_elc_req);
 
 int ldlm_prep_enqueue_req(struct obd_export *exp, struct ptlrpc_request *req,
-                          cfs_list_t *cancels, int count)
+                         struct list_head *cancels, int count)
 {
         return ldlm_prep_elc_req(exp, req, LUSTRE_DLM_VERSION, LDLM_ENQUEUE,
                                  LDLM_ENQUEUE_CANCEL_OFF, cancels, count);
 }
+EXPORT_SYMBOL(ldlm_prep_enqueue_req);
 
-/* If a request has some specific initialisation it is passed in @reqp,
+struct ptlrpc_request *ldlm_enqueue_pack(struct obd_export *exp, int lvb_len)
+{
+       struct ptlrpc_request *req;
+       int rc;
+       ENTRY;
+
+       req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_LDLM_ENQUEUE);
+       if (req == NULL)
+               RETURN(ERR_PTR(-ENOMEM));
+
+       rc = ldlm_prep_enqueue_req(exp, req, NULL, 0);
+       if (rc) {
+               ptlrpc_request_free(req);
+               RETURN(ERR_PTR(rc));
+       }
+
+       req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER, lvb_len);
+       ptlrpc_request_set_replen(req);
+       RETURN(req);
+}
+EXPORT_SYMBOL(ldlm_enqueue_pack);
+
+/**
+ * Client-side lock enqueue.
+ *
+ * If a request has some specific initialisation it is passed in \a reqp,
  * otherwise it is created in ldlm_cli_enqueue.
  *
- * Supports sync and async requests, pass @async flag accordingly. If a
+ * Supports sync and async requests, pass \a async flag accordingly. If a
  * request was created in ldlm_cli_enqueue and it is the async request,
- * pass it to the caller in @reqp. */
+ * pass it to the caller in \a reqp.
+ */
 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 const *policy, int *flags,
-                     void *lvb, __u32 lvb_len, struct lustre_handle *lockh,
-                     int async)
+                    ldlm_policy_data_t const *policy, __u64 *flags,
+                    void *lvb, __u32 lvb_len, enum lvb_type lvb_type,
+                    struct lustre_handle *lockh, int async)
 {
-        struct ldlm_namespace *ns = exp->exp_obd->obd_namespace;
+       struct ldlm_namespace *ns;
         struct ldlm_lock      *lock;
         struct ldlm_request   *body;
         int                    is_replay = *flags & LDLM_FL_REPLAY;
@@ -771,6 +886,8 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
 
         LASSERT(exp != NULL);
 
+       ns = exp->exp_obd->obd_namespace;
+
         /* If we're replaying this lock, just check some invariants.
          * If we're creating a new lock, get everything all setup nice. */
         if (is_replay) {
@@ -779,39 +896,38 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
                 LDLM_DEBUG(lock, "client-side enqueue START");
                 LASSERT(exp == lock->l_conn_export);
         } else {
-                const struct ldlm_callback_suite cbs = {
-                        .lcs_completion = einfo->ei_cb_cp,
-                        .lcs_blocking   = einfo->ei_cb_bl,
-                        .lcs_glimpse    = einfo->ei_cb_gl,
-                        .lcs_weigh      = einfo->ei_cb_wg
-                };
-                lock = ldlm_lock_create(ns, res_id, einfo->ei_type,
-                                        einfo->ei_mode, &cbs, einfo->ei_cbdata,
-                                        lvb_len);
-                if (lock == NULL)
-                        RETURN(-ENOMEM);
+               const struct ldlm_callback_suite cbs = {
+                       .lcs_completion = einfo->ei_cb_cp,
+                       .lcs_blocking   = einfo->ei_cb_bl,
+                       .lcs_glimpse    = einfo->ei_cb_gl
+               };
+               lock = ldlm_lock_create(ns, res_id, einfo->ei_type,
+                                       einfo->ei_mode, &cbs, einfo->ei_cbdata,
+                                       lvb_len, lvb_type);
+               if (IS_ERR(lock))
+                       RETURN(PTR_ERR(lock));
                 /* for the local lock, add the reference */
                 ldlm_lock_addref_internal(lock, einfo->ei_mode);
                 ldlm_lock2handle(lock, lockh);
-                if (policy != NULL) {
-                        /* INODEBITS_INTEROP: If the server does not support
-                         * inodebits, we will request a plain lock in the
-                         * descriptor (ldlm_lock2desc() below) but use an
-                         * inodebits lock internally with both bits set.
-                         */
-                        if (einfo->ei_type == LDLM_IBITS &&
-                            !(exp->exp_connect_flags & OBD_CONNECT_IBITS))
-                                lock->l_policy_data.l_inodebits.bits =
-                                        MDS_INODELOCK_LOOKUP |
-                                        MDS_INODELOCK_UPDATE;
-                        else
-                                lock->l_policy_data = *policy;
-                }
-
-                if (einfo->ei_type == LDLM_EXTENT)
-                        lock->l_req_extent = policy->l_extent;
-                LDLM_DEBUG(lock, "client-side enqueue START");
-        }
+               if (policy != NULL)
+                       lock->l_policy_data = *policy;
+
+               if (einfo->ei_type == LDLM_EXTENT) {
+                       /* extent lock without policy is a bug */
+                       if (policy == NULL)
+                               LBUG();
+
+                       lock->l_req_extent = policy->l_extent;
+               }
+               LDLM_DEBUG(lock, "client-side enqueue START, flags "LPX64"\n",
+                          *flags);
+       }
+
+       lock->l_conn_export = exp;
+       lock->l_export = NULL;
+       lock->l_blocking_ast = einfo->ei_cb_bl;
+       lock->l_flags |= (*flags & (LDLM_FL_NO_LRU | LDLM_FL_EXCL));
+        lock->l_last_activity = cfs_time_current_sec();
 
         /* lock not sent to server yet */
 
@@ -838,35 +954,22 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
                          DLM_LOCKREQ_OFF, len, (int)sizeof(*body));
         }
 
-        lock->l_conn_export = exp;
-        lock->l_export = NULL;
-        lock->l_blocking_ast = einfo->ei_cb_bl;
-
         /* Dump lock data into the request buffer */
         body = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
         ldlm_lock2desc(lock, &body->lock_desc);
-        body->lock_flags = *flags;
+       body->lock_flags = ldlm_flags_to_wire(*flags);
         body->lock_handle[0] = *lockh;
 
         /* Continue as normal. */
         if (!req_passed_in) {
-                if (lvb_len > 0) {
-                        req_capsule_extend(&req->rq_pill,
-                                           &RQF_LDLM_ENQUEUE_LVB);
-                        req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB,
-                                             RCL_SERVER, lvb_len);
-                }
-                ptlrpc_request_set_replen(req);
+               if (lvb_len > 0)
+                       req_capsule_extend(&req->rq_pill,
+                                          &RQF_LDLM_ENQUEUE_LVB);
+               req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
+                                    lvb_len);
+               ptlrpc_request_set_replen(req);
         }
 
-        /*
-         * Liblustre client doesn't get extent locks, except for O_APPEND case
-         * where [0, OBD_OBJECT_EOF] lock is taken, or truncate, where
-         * [i_size, OBD_OBJECT_EOF] lock is taken.
-         */
-        LASSERT(ergo(LIBLUSTRE_CLIENT, einfo->ei_type != LDLM_EXTENT ||
-                     policy->l_extent.end == OBD_OBJECT_EOF));
-
         if (async) {
                 LASSERT(reqp != NULL);
                 RETURN(0);
@@ -895,6 +998,7 @@ int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
 
         RETURN(rc);
 }
+EXPORT_SYMBOL(ldlm_cli_enqueue);
 
 static int ldlm_cli_convert_local(struct ldlm_lock *lock, int new_mode,
                                   __u32 *flags)
@@ -902,7 +1006,7 @@ 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();
         }
@@ -913,7 +1017,7 @@ static int ldlm_cli_convert_local(struct ldlm_lock *lock, int new_mode,
                 ldlm_reprocess_all(res);
                 rc = 0;
         } else {
-                rc = EDEADLOCK;
+               rc = LUSTRE_EDEADLK;
         }
         LDLM_DEBUG(lock, "client-side local convert handler END");
         LDLM_LOCK_PUT(lock);
@@ -958,7 +1062,7 @@ int ldlm_cli_convert(struct lustre_handle *lockh, int new_mode, __u32 *flags)
         body->lock_handle[0] = lock->l_remote_handle;
 
         body->lock_desc.l_req_mode = new_mode;
-        body->lock_flags = *flags;
+       body->lock_flags = ldlm_flags_to_wire(*flags);
 
 
         ptlrpc_request_set_replen(req);
@@ -985,7 +1089,7 @@ int ldlm_cli_convert(struct lustre_handle *lockh, int new_mode, __u32 *flags)
                                 GOTO(out, rc);
                 }
         } else {
-                rc = EDEADLOCK;
+               rc = LUSTRE_EDEADLK;
         }
         EXIT;
  out:
@@ -994,29 +1098,31 @@ int ldlm_cli_convert(struct lustre_handle *lockh, int new_mode, __u32 *flags)
         return rc;
 }
 
-/* Cancel locks locally.
+/**
+ * Cancel locks locally.
  * Returns:
- * LDLM_FL_LOCAL_ONLY if tere is no need in a CANCEL rpc to the server;
- * LDLM_FL_CANCELING otherwise;
- * LDLM_FL_BL_AST if there is a need in a separate CANCEL rpc. */
-static int ldlm_cli_cancel_local(struct ldlm_lock *lock)
+ * \retval LDLM_FL_LOCAL_ONLY if there is no need for a CANCEL RPC to the server
+ * \retval LDLM_FL_CANCELING otherwise;
+ * \retval LDLM_FL_BL_AST if there is a need for a separate CANCEL RPC.
+ */
+static __u64 ldlm_cli_cancel_local(struct ldlm_lock *lock)
 {
-        int rc = LDLM_FL_LOCAL_ONLY;
+       __u64 rc = LDLM_FL_LOCAL_ONLY;
         ENTRY;
 
         if (lock->l_conn_export) {
-                int local_only;
+                bool local_only;
 
                 LDLM_DEBUG(lock, "client-side cancel");
                 /* Set this flag to prevent others from getting new references*/
                 lock_res_and_lock(lock);
-                lock->l_flags |= LDLM_FL_CBPENDING;
-                local_only = (lock->l_flags &
-                              (LDLM_FL_LOCAL_ONLY|LDLM_FL_CANCEL_ON_BLOCK));
-                ldlm_cancel_callback(lock);
-                rc = (lock->l_flags & LDLM_FL_BL_AST) ?
-                        LDLM_FL_BL_AST : LDLM_FL_CANCELING;
-                unlock_res_and_lock(lock);
+               ldlm_set_cbpending(lock);
+               local_only = !!(lock->l_flags &
+                               (LDLM_FL_LOCAL_ONLY|LDLM_FL_CANCEL_ON_BLOCK));
+               ldlm_cancel_callback(lock);
+               rc = (ldlm_is_bl_ast(lock)) ?
+                       LDLM_FL_BL_AST : LDLM_FL_CANCELING;
+               unlock_res_and_lock(lock);
 
                 if (local_only) {
                         CDEBUG(D_DLMTRACE, "not sending request (at caller's "
@@ -1025,7 +1131,7 @@ 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();
                 }
@@ -1037,10 +1143,11 @@ static int ldlm_cli_cancel_local(struct ldlm_lock *lock)
         RETURN(rc);
 }
 
-/* Pack @count locks in @head into ldlm_request buffer at the offset @off,
-   of the request @req. */
+/**
+ * Pack \a count locks in \a head into ldlm_request buffer of request \a req.
+ */
 static void ldlm_cancel_pack(struct ptlrpc_request *req,
-                             cfs_list_t *head, int count)
+                            struct list_head *head, int count)
 {
         struct ldlm_request *dlm;
         struct ldlm_lock *lock;
@@ -1060,7 +1167,7 @@ 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. */
-        cfs_list_for_each_entry(lock, head, l_bl_ast) {
+       list_for_each_entry(lock, head, l_bl_ast) {
                 if (!count--)
                         break;
                 LASSERT(lock->l_conn_export);
@@ -1073,9 +1180,10 @@ static void ldlm_cancel_pack(struct ptlrpc_request *req,
         EXIT;
 }
 
-/* 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, cfs_list_t *cancels,
+/**
+ * Prepare and send a batched cancel RPC. It will include \a count lock
+ * handles of locks given in \a cancels list. */
+int ldlm_cli_cancel_req(struct obd_export *exp, struct list_head *cancels,
                         int count, ldlm_cancel_flags_t flags)
 {
         struct ptlrpc_request *req = NULL;
@@ -1087,9 +1195,9 @@ int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
         LASSERT(exp != NULL);
         LASSERT(count > 0);
 
-        OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_PAUSE_CANCEL, obd_fail_val);
+        CFS_FAIL_TIMEOUT(OBD_FAIL_LDLM_PAUSE_CANCEL, cfs_fail_val);
 
-        if (OBD_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_RACE))
+        if (CFS_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_RACE))
                 RETURN(count);
 
         free = ldlm_format_handles_avail(class_exp2cliimp(exp),
@@ -1098,8 +1206,6 @@ int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
                 count = free;
 
         while (1) {
-                int bufcount;
-
                 imp = class_exp2cliimp(exp);
                 if (imp == NULL || imp->imp_invalid) {
                         CDEBUG(D_DLMTRACE,
@@ -1111,7 +1217,7 @@ int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
                 if (req == NULL)
                         GOTO(out, rc = -ENOMEM);
 
-                bufcount = req_capsule_filled_sizes(&req->rq_pill, RCL_CLIENT);
+                req_capsule_filled_sizes(&req->rq_pill, RCL_CLIENT);
                 req_capsule_set_size(&req->rq_pill, &RMF_DLM_REQ, RCL_CLIENT,
                                      ldlm_request_bufsize(count, LDLM_CANCEL));
 
@@ -1120,8 +1226,6 @@ int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
                         ptlrpc_request_free(req);
                         GOTO(out, rc);
                 }
-                req->rq_no_resend = 1;
-                req->rq_no_delay = 1;
 
                 req->rq_request_portal = LDLM_CANCEL_REQUEST_PORTAL;
                 req->rq_reply_portal = LDLM_CANCEL_REPLY_PORTAL;
@@ -1131,13 +1235,13 @@ int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
 
                 ptlrpc_request_set_replen(req);
                 if (flags & LCF_ASYNC) {
-                        ptlrpcd_add_req(req, PSCOPE_OTHER);
+                        ptlrpcd_add_req(req, PDL_POLICY_LOCAL, -1);
                         sent = count;
                         GOTO(out, 0);
                 } else {
                         rc = ptlrpc_queue_wait(req);
                 }
-                if (rc == ESTALE) {
+               if (rc == LUSTRE_ESTALE) {
                         CDEBUG(D_DLMTRACE, "client/server (nid %s) "
                                "out of sync -- not fatal\n",
                                libcfs_nid2str(req->rq_import->
@@ -1148,9 +1252,11 @@ int ldlm_cli_cancel_req(struct obd_export *exp, cfs_list_t *cancels,
                         ptlrpc_req_finished(req);
                         continue;
                 } else if (rc != ELDLM_OK) {
-                        CERROR("Got rc %d from cancel RPC: canceling "
-                               "anyway\n", rc);
-                        break;
+                       /* -ESHUTDOWN is common on umount */
+                       CDEBUG_LIMIT(rc == -ESHUTDOWN ? D_DLMTRACE : D_ERROR,
+                                    "Got rc %d from cancel RPC: "
+                                    "canceling anyway\n", rc);
+                       break;
                 }
                 sent = count;
                 break;
@@ -1169,12 +1275,12 @@ static inline struct ldlm_pool *ldlm_imp2pl(struct obd_import *imp)
 }
 
 /**
- * Update client's obd pool related fields with new SLV and Limit from \a req.
+ * Update client's OBD pool related fields with new SLV and Limit from \a req.
  */
 int ldlm_cli_update_pool(struct ptlrpc_request *req)
 {
         struct obd_device *obd;
-        __u64 old_slv, new_slv;
+        __u64 new_slv;
         __u32 new_limit;
         ENTRY;
         if (unlikely(!req->rq_import || !req->rq_import->imp_obd ||
@@ -1186,13 +1292,11 @@ int ldlm_cli_update_pool(struct ptlrpc_request *req)
                 RETURN(0);
         }
 
-        /*
-         * In some cases RPC may contain slv and limit zeroed out. This is
-         * the case when server does not support lru resize feature. This is
-         * also possible in some recovery cases when server side reqs have no
-         * ref to obd export and thus access to server side namespace is no
-         * possible.
-         */
+       /* In some cases RPC may contain SLV and limit zeroed out. This
+        * is the case when server does not support LRU resize feature.
+        * This is also possible in some recovery cases when server-side
+        * reqs have no reference to the OBD export and thus access to
+        * server-side namespace is not possible. */
         if (lustre_msg_get_slv(req->rq_repmsg) == 0 ||
             lustre_msg_get_limit(req->rq_repmsg) == 0) {
                 DEBUG_REQ(D_HA, req, "Zero SLV or Limit found "
@@ -1206,49 +1310,52 @@ int ldlm_cli_update_pool(struct ptlrpc_request *req)
         new_slv = lustre_msg_get_slv(req->rq_repmsg);
         obd = req->rq_import->imp_obd;
 
-        /*
-         * Set new SLV and Limit to obd fields to make accessible for pool
-         * thread. We do not access obd_namespace and pool directly here
-         * as there is no reliable way to make sure that they are still
-         * alive in cleanup time. Evil races are possible which may cause
-         * oops in that time.
-         */
-        cfs_write_lock(&obd->obd_pool_lock);
-        old_slv = obd->obd_pool_slv;
+       /* Set new SLV and limit in OBD fields to make them accessible
+        * to the pool thread. We do not access obd_namespace and pool
+        * directly here as there is no reliable way to make sure that
+        * they are still alive at cleanup time. Evil races are possible
+        * which may cause Oops at that time. */
+       write_lock(&obd->obd_pool_lock);
         obd->obd_pool_slv = new_slv;
         obd->obd_pool_limit = new_limit;
-        cfs_write_unlock(&obd->obd_pool_lock);
+       write_unlock(&obd->obd_pool_lock);
 
         RETURN(0);
 }
-EXPORT_SYMBOL(ldlm_cli_update_pool);
 
-int ldlm_cli_cancel(struct lustre_handle *lockh)
+/**
+ * Client side lock cancel.
+ *
+ * Lock must not have any readers or writers by this time.
+ */
+int ldlm_cli_cancel(struct lustre_handle *lockh,
+                   ldlm_cancel_flags_t cancel_flags)
 {
-        struct obd_export *exp;
-        int avail, flags, count = 1, rc = 0;
-        struct ldlm_namespace *ns;
-        struct ldlm_lock *lock;
-        CFS_LIST_HEAD(cancels);
-        ENTRY;
+       struct obd_export *exp;
+       int avail, flags, count = 1;
+       __u64 rc = 0;
+       struct ldlm_namespace *ns;
+       struct ldlm_lock *lock;
+       struct list_head cancels = LIST_HEAD_INIT(cancels);
+       ENTRY;
 
         /* concurrent cancels on the same handle can happen */
         lock = ldlm_handle2lock_long(lockh, LDLM_FL_CANCELING);
-        if (lock == NULL) {
-                LDLM_DEBUG_NOLOCK("lock is already being destroyed\n");
-                RETURN(0);
-        }
-
-        rc = ldlm_cli_cancel_local(lock);
-        if (rc < 0 || rc == LDLM_FL_LOCAL_ONLY) {
-                LDLM_LOCK_RELEASE(lock);
-                RETURN(rc < 0 ? rc : 0);
-        }
-        /* 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(cfs_list_empty(&lock->l_bl_ast));
-        cfs_list_add(&lock->l_bl_ast, &cancels);
+       if (lock == NULL) {
+               LDLM_DEBUG_NOLOCK("lock is already being destroyed");
+               RETURN(0);
+       }
+
+       rc = ldlm_cli_cancel_local(lock);
+       if (rc == LDLM_FL_LOCAL_ONLY || cancel_flags & LCF_LOCAL) {
+               LDLM_LOCK_RELEASE(lock);
+               RETURN(0);
+       }
+       /* 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);
 
         exp = lock->l_conn_export;
         if (exp_connect_cancelset(exp)) {
@@ -1257,27 +1364,31 @@ 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,
                                                LCF_BL_AST, flags);
         }
-        ldlm_cli_cancel_list(&cancels, count, NULL, 0);
+       ldlm_cli_cancel_list(&cancels, count, NULL, cancel_flags);
         RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_cli_cancel);
 
-/* 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 */
-int ldlm_cli_cancel_list_local(cfs_list_t *cancels, int count,
-                               ldlm_cancel_flags_t flags)
+/**
+ * Locally cancel up to \a count locks in list \a cancels.
+ * Return the number of cancelled locks.
+ */
+int ldlm_cli_cancel_list_local(struct list_head *cancels, int count,
+                              ldlm_cancel_flags_t flags)
 {
-        CFS_LIST_HEAD(head);
-        struct ldlm_lock *lock, *next;
-        int left = 0, bl_ast = 0, rc;
+       struct list_head head = LIST_HEAD_INIT(head);
+       struct ldlm_lock *lock, *next;
+       int left = 0, bl_ast = 0;
+       __u64 rc;
 
         left = count;
-        cfs_list_for_each_entry_safe(lock, next, cancels, l_bl_ast) {
+       list_for_each_entry_safe(lock, next, cancels, l_bl_ast) {
                 if (left-- == 0)
                         break;
 
@@ -1287,20 +1398,23 @@ int ldlm_cli_cancel_list_local(cfs_list_t *cancels, int count,
                 } else {
                         rc = ldlm_cli_cancel_local(lock);
                 }
-                if (!(flags & LCF_BL_AST) && (rc == LDLM_FL_BL_AST)) {
-                        LDLM_DEBUG(lock, "Cancel lock separately");
-                        cfs_list_del_init(&lock->l_bl_ast);
-                        cfs_list_add(&lock->l_bl_ast, &head);
-                        bl_ast ++;
+               /* Until we have compound requests and can send LDLM_CANCEL
+                * requests batched with generic RPCs, we need to send cancels
+                * with the LDLM_FL_BL_AST flag in a separate RPC from
+                * the one being generated now. */
+               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);
+                       bl_ast++;
                         continue;
                 }
                 if (rc == LDLM_FL_LOCAL_ONLY) {
                         /* CANCEL RPC should not be sent to server. */
-                        cfs_list_del_init(&lock->l_bl_ast);
+                       list_del_init(&lock->l_bl_ast);
                         LDLM_LOCK_RELEASE(lock);
                         count--;
                 }
-
         }
         if (bl_ast > 0) {
                 count -= bl_ast;
@@ -1311,9 +1425,41 @@ int ldlm_cli_cancel_list_local(cfs_list_t *cancels, int count,
 }
 
 /**
- * Callback function for lru-resize 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.
+ * 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_no_wait_policy(struct ldlm_namespace *ns,
+                                                    struct ldlm_lock *lock,
+                                                    int unused, int added,
+                                                    int count)
+{
+       ldlm_policy_res_t result = LDLM_POLICY_CANCEL_LOCK;
+
+       /* don't check added & count since we want to process all locks
+        * from unused list.
+        * It's fine to not take lock to access lock->l_resource since
+        * the lock has already been granted so it won't change. */
+       switch (lock->l_resource->lr_type) {
+               case LDLM_EXTENT:
+               case LDLM_IBITS:
+                       if (ns->ns_cancel != NULL && ns->ns_cancel(lock) != 0)
+                               break;
+               default:
+                       result = LDLM_POLICY_SKIP_LOCK;
+                       lock_res_and_lock(lock);
+                       ldlm_set_skipped(lock);
+                       unlock_res_and_lock(lock);
+                       break;
+       }
+
+       RETURN(result);
+}
+
+/**
+ * Callback function for LRU-resize policy. Decides 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
  *
@@ -1324,41 +1470,43 @@ static ldlm_policy_res_t ldlm_cancel_lrur_policy(struct ldlm_namespace *ns,
                                                  int unused, int added,
                                                  int count)
 {
-        cfs_time_t cur = cfs_time_current();
-        struct ldlm_pool *pl = &ns->ns_pool;
-        __u64 slv, lvf, lv;
-        cfs_time_t la;
-
-        /*
-         * Stop lru processing when we reached passed @count or checked all
-         * locks in lru.
-         */
-        if (count && added >= count)
-                return LDLM_POLICY_KEEP_LOCK;
-
-        slv = ldlm_pool_get_slv(pl);
-        lvf = ldlm_pool_get_lvf(pl);
-        la = cfs_duration_sec(cfs_time_sub(cur,
-                              lock->l_last_used));
-
-        /*
-         * Stop when slv is not yet come from server or lv is smaller than
-         * it is.
-         */
-        lv = lvf * la * unused;
-
-        /*
-         * Inform pool about current CLV to see it via proc.
-         */
-        ldlm_pool_set_clv(pl, lv);
-        return (slv == 0 || lv < slv) ?
-                LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
+       cfs_time_t cur = cfs_time_current();
+       struct ldlm_pool *pl = &ns->ns_pool;
+       __u64 slv, lvf, lv;
+       cfs_time_t la;
+
+       /* Stop LRU processing when we reach past @count or have checked all
+        * locks in LRU. */
+       if (count && added >= count)
+               return LDLM_POLICY_KEEP_LOCK;
+
+       /* Despite of the LV, It doesn't make sense to keep the lock which
+        * is unused for ns_max_age time. */
+       if (cfs_time_after(cfs_time_current(),
+                          cfs_time_add(lock->l_last_used, ns->ns_max_age)))
+               return LDLM_POLICY_CANCEL_LOCK;
+
+       slv = ldlm_pool_get_slv(pl);
+       lvf = ldlm_pool_get_lvf(pl);
+       la = cfs_duration_sec(cfs_time_sub(cur,
+                             lock->l_last_used));
+       lv = lvf * la * unused;
+
+       /* Inform pool about current CLV to see it via proc. */
+       ldlm_pool_set_clv(pl, lv);
+
+       /* Stop when SLV is not yet come from server or lv is smaller than
+        * it is. */
+       if (slv == 0 || lv < slv)
+               return LDLM_POLICY_KEEP_LOCK;
+
+       return LDLM_POLICY_CANCEL_LOCK;
 }
 
 /**
  * Callback function for proc used 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.
+ * \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
  *
@@ -1369,57 +1517,50 @@ static ldlm_policy_res_t ldlm_cancel_passed_policy(struct ldlm_namespace *ns,
                                                    int unused, int added,
                                                    int count)
 {
-        /*
-         * Stop lru processing when we reached passed @count or checked all
-         * locks in lru.
-         */
-        return (added >= count) ?
-                LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
+       /* Stop LRU processing when we reach past @count or have checked all
+        * locks in LRU. */
+       return (added >= count) ?
+               LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
 }
 
 /**
- * Callback function for aged 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.
+ * Callback function for aged policy. Makes decision whether to keep \a lock in
+ * LRU for current 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
  */
 static ldlm_policy_res_t ldlm_cancel_aged_policy(struct ldlm_namespace *ns,
-                                                 struct ldlm_lock *lock,
-                                                 int unused, int added,
-                                                 int count)
+                                                struct ldlm_lock *lock,
+                                                int unused, int added,
+                                                int count)
 {
-        /*
-         * Stop lru processing if young lock is found and we reached passed
-         * @count.
-         */
-        return ((added >= count) &&
-                cfs_time_before(cfs_time_current(),
-                                cfs_time_add(lock->l_last_used,
-                                             ns->ns_max_age))) ?
-                LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
+       if ((added >= count) &&
+           cfs_time_before(cfs_time_current(),
+                           cfs_time_add(lock->l_last_used, ns->ns_max_age)))
+               return LDLM_POLICY_KEEP_LOCK;
+
+       return LDLM_POLICY_CANCEL_LOCK;
 }
 
 /**
- * Callback function for default 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.
+ * Callback function for default policy. Makes decision whether to keep \a lock
+ * in LRU for current 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
  */
 static ldlm_policy_res_t ldlm_cancel_default_policy(struct ldlm_namespace *ns,
-                                                    struct ldlm_lock *lock,
-                                                    int unused, int added,
-                                                    int count)
+                                                   struct ldlm_lock *lock,
+                                                   int unused, int added,
+                                                   int count)
 {
-        /*
-         * Stop lru processing when we reached passed @count or checked all
-         * locks in lru.
-         */
+       /* Stop LRU processing when we reach past count or have checked all
+        * locks in LRU. */
         return (added >= count) ?
                 LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
 }
@@ -1431,6 +1572,9 @@ 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)
                         /* We kill passed number of old locks. */
@@ -1447,42 +1591,51 @@ ldlm_cancel_lru_policy(struct ldlm_namespace *ns, int flags)
         return ldlm_cancel_default_policy;
 }
 
-/* - Free space in lru for @count new locks,
+/**
+ * - Free space in LRU for \a count new locks,
  *   redundant unused locks are canceled locally;
  * - also cancel locally unused aged locks;
- * - do not cancel more than @max locks;
- * - GET the found locks and add them into the @cancels list.
+ * - do not cancel more than \a max locks;
+ * - GET the found locks and add them into the \a cancels list.
  *
  * A client lock can be added to the l_bl_ast list only when it is
- * marked LDLM_FL_CANCELING. Otherwise, somebody is already doing CANCEL.
- * There are the following use cases: ldlm_cancel_resource_local(),
- * ldlm_cancel_lru_local() and ldlm_cli_cancel(), which check&set this
- * flag properly. As any attempt to cancel a lock rely on this flag,
- * l_bl_ast list is accessed later without any special locking.
+ * marked LDLM_FL_CANCELING. Otherwise, somebody is already doing
+ * CANCEL.  There are the following use cases:
+ * ldlm_cancel_resource_local(), ldlm_cancel_lru_local() and
+ * ldlm_cli_cancel(), which check and set this flag properly. As any
+ * attempt to cancel a lock rely on this flag, l_bl_ast list is accessed
+ * later without any special locking.
  *
- * Calling policies for enabled lru resize:
+ * Calling policies for enabled LRU resize:
  * ----------------------------------------
- * flags & LDLM_CANCEL_LRUR - use lru resize policy (SLV from server) to
- *                            cancel not more than @count locks;
+ * flags & LDLM_CANCEL_LRUR - use LRU resize policy (SLV from server) to
+ *                            cancel not more than \a count locks;
  *
- * flags & LDLM_CANCEL_PASSED - cancel @count number of old locks (located at
- *                              the beginning of lru list);
+ * flags & LDLM_CANCEL_PASSED - cancel \a count number of old locks (located at
+ *                              the beginning of LRU list);
  *
- * flags & LDLM_CANCEL_SHRINK - cancel not more than @count locks according to
+ * flags & LDLM_CANCEL_SHRINK - cancel not more than \a count locks according to
  *                              memory pressre policy function;
  *
- * flags & LDLM_CANCEL_AGED -   cancel alocks according to "aged policy".
+ * flags & LDLM_CANCEL_AGED - cancel \a count locks 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.
  */
-static int ldlm_prepare_lru_list(struct ldlm_namespace *ns, cfs_list_t *cancels,
-                                 int count, int max, int flags)
+static int ldlm_prepare_lru_list(struct ldlm_namespace *ns,
+                                struct list_head *cancels, int count, int max,
+                                int flags)
 {
-        ldlm_cancel_lru_policy_t pf;
-        struct ldlm_lock *lock, *next;
-        int added = 0, unused;
-        ENTRY;
+       ldlm_cancel_lru_policy_t pf;
+       struct ldlm_lock *lock, *next;
+       int added = 0, unused, remained;
+       ENTRY;
 
-        cfs_spin_lock(&ns->ns_unused_lock);
+       spin_lock(&ns->ns_lock);
         unused = ns->ns_nr_unused;
+        remained = unused;
 
         if (!ns_connect_lru_resize(ns))
                 count += unused - ns->ns_max_unused;
@@ -1490,104 +1643,120 @@ static int ldlm_prepare_lru_list(struct ldlm_namespace *ns, cfs_list_t *cancels,
         pf = ldlm_cancel_lru_policy(ns, flags);
         LASSERT(pf != NULL);
 
-        while (!cfs_list_empty(&ns->ns_unused_list)) {
+       while (!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;
 
-                cfs_list_for_each_entry_safe(lock, next, &ns->ns_unused_list,
-                                             l_lru){
+               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));
+                       LASSERT(!ldlm_is_bl_ast(lock));
 
-                        /* Somebody is already doing CANCEL. No need in this
-                         * lock in lru, do not traverse it again. */
-                        if (!(lock->l_flags & LDLM_FL_CANCELING))
-                                break;
+                       if (flags & LDLM_CANCEL_NO_WAIT &&
+                           ldlm_is_skipped(lock))
+                               /* already processed */
+                               continue;
 
-                        ldlm_lock_remove_from_lru_nolock(lock);
-                }
-                if (&lock->l_lru == &ns->ns_unused_list)
-                        break;
-
-                LDLM_LOCK_GET(lock);
-                cfs_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.
-                 *
-                 * Even for shrinker policy we stop scanning if
-                 * we find a lock that should stay in the cache.
-                 * We should take into account lock age anyway
-                 * as new lock even if it is small of weight is
-                 * valuable resource.
-                 *
-                 * That is, for shrinker policy we drop only
-                 * 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) {
-                        lu_ref_del(&lock->l_reference,
-                                   __FUNCTION__, cfs_current());
-                        LDLM_LOCK_RELEASE(lock);
-                        cfs_spin_lock(&ns->ns_unused_lock);
-                        break;
-                }
+                       /* Somebody is already doing CANCEL. No need for this
+                        * lock in LRU, do not traverse it again. */
+                       if (!ldlm_is_canceling(lock))
+                                break;
 
-                lock_res_and_lock(lock);
-                /* Check flags again under the lock. */
-                if ((lock->l_flags & LDLM_FL_CANCELING) ||
-                    (ldlm_lock_remove_from_lru(lock) == 0)) {
-                        /* other thread is removing lock from lru or
-                         * somebody is already doing CANCEL or
-                         * there is a blocking request which will send
-                         * cancel by itseft or the lock is matched
-                         * is already not unused. */
-                        unlock_res_and_lock(lock);
-                        lu_ref_del(&lock->l_reference,
-                                   __FUNCTION__, cfs_current());
-                        LDLM_LOCK_RELEASE(lock);
-                        cfs_spin_lock(&ns->ns_unused_lock);
-                        continue;
-                }
-                LASSERT(!lock->l_readers && !lock->l_writers);
-
-                /* If we have chosen to cancel this lock voluntarily, we
-                 * better send cancel notification to server, so that it
-                 * frees appropriate state. This might lead to a race
-                 * where while we are doing cancel here, server is also
-                 * silently cancelling this lock. */
-                lock->l_flags &= ~LDLM_FL_CANCEL_ON_BLOCK;
-
-                /* Setting the CBPENDING flag is a little misleading,
-                 * but prevents an important race; namely, once
-                 * CBPENDING is set, the lock can accumulate no more
-                 * readers/writers. Since readers and writers are
-                 * already zero here, ldlm_lock_decref() won't see
-                 * this flag and call l_blocking_ast */
-                lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING;
-
-                /* 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
-                 * 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(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());
-                cfs_spin_lock(&ns->ns_unused_lock);
-                added++;
-                unused--;
-        }
-        cfs_spin_unlock(&ns->ns_unused_lock);
-        RETURN(added);
+                       ldlm_lock_remove_from_lru_nolock(lock);
+               }
+               if (&lock->l_lru == &ns->ns_unused_list)
+                       break;
+
+               LDLM_LOCK_GET(lock);
+               spin_unlock(&ns->ns_lock);
+               lu_ref_add(&lock->l_reference, __FUNCTION__, current);
+
+               /* Pass the lock through the policy filter and see if it
+                * should stay in LRU.
+                *
+                * Even for shrinker policy we stop scanning if
+                * we find a lock that should stay in the cache.
+                * We should take into account lock age anyway
+                * as a new lock is a valuable resource even if
+                * it has a low weight.
+                *
+                * That is, for shrinker policy we drop only
+                * old locks, but additionally choose them by
+                * their weight. Big extent locks will stay in
+                * the cache. */
+               result = pf(ns, lock, unused, added, count);
+               if (result == LDLM_POLICY_KEEP_LOCK) {
+                       lu_ref_del(&lock->l_reference,
+                                  __FUNCTION__, current);
+                       LDLM_LOCK_RELEASE(lock);
+                       spin_lock(&ns->ns_lock);
+                       break;
+               }
+               if (result == LDLM_POLICY_SKIP_LOCK) {
+                       lu_ref_del(&lock->l_reference,
+                                  __func__, current);
+                       LDLM_LOCK_RELEASE(lock);
+                       spin_lock(&ns->ns_lock);
+                       continue;
+               }
+
+               lock_res_and_lock(lock);
+               /* Check flags again under the lock. */
+               if (ldlm_is_canceling(lock) ||
+                   (ldlm_lock_remove_from_lru(lock) == 0)) {
+                       /* Another thread is removing lock from LRU, or
+                        * somebody is already doing CANCEL, or there
+                        * is a blocking request which will send cancel
+                        * by itself, or the lock is no longer unused. */
+                       unlock_res_and_lock(lock);
+                       lu_ref_del(&lock->l_reference, __FUNCTION__, current);
+                       LDLM_LOCK_RELEASE(lock);
+                       spin_lock(&ns->ns_lock);
+                       continue;
+               }
+               LASSERT(!lock->l_readers && !lock->l_writers);
+
+               /* If we have chosen to cancel this lock voluntarily, we
+                * better send cancel notification to server, so that it
+                * frees appropriate state. This might lead to a race
+                * where while we are doing cancel here, server is also
+                * silently cancelling this lock. */
+               ldlm_clear_cancel_on_block(lock);
+
+               /* Setting the CBPENDING flag is a little misleading,
+                * but prevents an important race; namely, once
+                * CBPENDING is set, the lock can accumulate no more
+                * readers/writers. Since readers and writers are
+                * already zero here, ldlm_lock_decref() won't see
+                * this flag and call l_blocking_ast */
+               lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING;
+
+               /* 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 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);
+               unlock_res_and_lock(lock);
+               lu_ref_del(&lock->l_reference, __FUNCTION__, current);
+               spin_lock(&ns->ns_lock);
+               added++;
+               unused--;
+       }
+       spin_unlock(&ns->ns_lock);
+       RETURN(added);
 }
 
-int ldlm_cancel_lru_local(struct ldlm_namespace *ns, cfs_list_t *cancels,
+int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
                           int count, int max, ldlm_cancel_flags_t cancel_flags,
                           int flags)
 {
@@ -1598,45 +1767,49 @@ int ldlm_cancel_lru_local(struct ldlm_namespace *ns, cfs_list_t *cancels,
         return ldlm_cli_cancel_list_local(cancels, added, cancel_flags);
 }
 
-/* when called with LDLM_ASYNC the blocking callback will be handled
+/**
+ * Cancel at least \a nr locks from given namespace LRU.
+ *
+ * When called with LCF_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 mode,
-                    int flags)
+ * asked to call the callback.  When called with LCF_ASYNC the blocking
+ * callback will be performed in this function.
+ */
+int ldlm_cancel_lru(struct ldlm_namespace *ns, int nr,
+                   ldlm_cancel_flags_t cancel_flags,
+                   int flags)
 {
-        CFS_LIST_HEAD(cancels);
-        int count, rc;
-        ENTRY;
-
-#ifndef __KERNEL__
-        mode = LDLM_SYNC; /* force to be sync in user space */
-#endif
-        /* 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);
-
-        RETURN(0);
+       struct list_head cancels = LIST_HEAD_INIT(cancels);
+       int count, rc;
+       ENTRY;
+
+       /* 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, cancel_flags);
+       if (rc == 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. */
+/**
+ * Find and cancel locally unused locks found on resource, matched to the
+ * given policy, mode. GET the found locks and add them into the \a cancels
+ * list.
+ */
 int ldlm_cancel_resource_local(struct ldlm_resource *res,
-                               cfs_list_t *cancels,
-                               ldlm_policy_data_t *policy,
-                               ldlm_mode_t mode, int lock_flags,
-                               ldlm_cancel_flags_t cancel_flags, void *opaque)
+                              struct list_head *cancels,
+                              ldlm_policy_data_t *policy,
+                              ldlm_mode_t mode, __u64 lock_flags,
+                              ldlm_cancel_flags_t cancel_flags, void *opaque)
 {
         struct ldlm_lock *lock;
         int count = 0;
         ENTRY;
 
         lock_res(res);
-        cfs_list_for_each_entry(lock, &res->lr_granted, l_res_link) {
+       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);
@@ -1647,11 +1820,10 @@ int ldlm_cancel_resource_local(struct ldlm_resource *res,
                 if (lock->l_readers || lock->l_writers)
                         continue;
 
-                /* If somebody is already doing CANCEL, or blocking ast came,
-                 * skip this lock. */
-                if (lock->l_flags & LDLM_FL_BL_AST ||
-                    lock->l_flags & LDLM_FL_CANCELING)
-                        continue;
+               /* If somebody is already doing CANCEL, or blocking AST came,
+                * skip this lock. */
+               if (ldlm_is_bl_ast(lock) || ldlm_is_canceling(lock))
+                       continue;
 
                 if (lockmode_compat(lock->l_granted_mode, mode))
                         continue;
@@ -1663,12 +1835,12 @@ int ldlm_cancel_resource_local(struct ldlm_resource *res,
                       policy->l_inodebits.bits))
                         continue;
 
-                /* See CBPENDING comment in ldlm_cancel_lru */
-                lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING |
-                                 lock_flags;
+               /* See CBPENDING comment in ldlm_cancel_lru */
+               lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING |
+                                lock_flags;
 
-                LASSERT(cfs_list_empty(&lock->l_bl_ast));
-                cfs_list_add(&lock->l_bl_ast, cancels);
+               LASSERT(list_empty(&lock->l_bl_ast));
+               list_add(&lock->l_bl_ast, cancels);
                 LDLM_LOCK_GET(lock);
                 count++;
         }
@@ -1676,31 +1848,36 @@ int ldlm_cancel_resource_local(struct ldlm_resource *res,
 
         RETURN(ldlm_cli_cancel_list_local(cancels, count, cancel_flags));
 }
+EXPORT_SYMBOL(ldlm_cancel_resource_local);
 
-/* If @req is NULL, send CANCEL request to server with handles of locks
- * in the @cancels. If EARLY_CANCEL is not supported, send CANCEL requests
+/**
+ * Cancel client-side locks from a list and send/prepare cancel RPCs to the
+ * server.
+ * If \a req is NULL, send CANCEL request to server with handles of locks
+ * in the \a cancels. If EARLY_CANCEL is not supported, send CANCEL requests
  * separately per lock.
- * 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(cfs_list_t *cancels, int count,
+ * If \a req is not NULL, put handles of locks in \a cancels into the request
+ * buffer at the offset \a off.
+ * Destroy \a cancels at the end.
+ */
+int ldlm_cli_cancel_list(struct list_head *cancels, int count,
                          struct ptlrpc_request *req, ldlm_cancel_flags_t flags)
 {
         struct ldlm_lock *lock;
         int res = 0;
         ENTRY;
 
-        if (cfs_list_empty(cancels) || count == 0)
+       if (list_empty(cancels) || count == 0)
                 RETURN(0);
 
         /* XXX: requests (both batched and not) could be sent in parallel.
          * Usually it is enough to have just 1 RPC, but it is possible that
-         * there are to many locks to be cancelled in LRU or on a resource.
+         * there are too many locks to be cancelled in LRU or on a resource.
          * It would also speed up the case when the server does not support
          * the feature. */
         while (count > 0) {
-                LASSERT(!cfs_list_empty(cancels));
-                lock = cfs_list_entry(cancels->next, struct ldlm_lock,
+               LASSERT(!list_empty(cancels));
+               lock = list_entry(cancels->next, struct ldlm_lock,
                                       l_bl_ast);
                 LASSERT(lock->l_conn_export);
 
@@ -1717,10 +1894,11 @@ int ldlm_cli_cancel_list(cfs_list_t *cancels, int count,
                                                   cancels, 1, flags);
                 }
 
-                if (res < 0) {
-                        CERROR("ldlm_cli_cancel_list: %d\n", res);
-                        res = count;
-                }
+               if (res < 0) {
+                       CDEBUG_LIMIT(res == -ESHUTDOWN ? D_DLMTRACE : D_ERROR,
+                                    "ldlm_cli_cancel_list: %d\n", res);
+                       res = count;
+               }
 
                 count -= res;
                 ldlm_lock_list_put(cancels, l_bl_ast, res);
@@ -1728,52 +1906,67 @@ int ldlm_cli_cancel_list(cfs_list_t *cancels, int count,
         LASSERT(count == 0);
         RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_cli_cancel_list);
 
+/**
+ * Cancel all locks on a resource that have 0 readers/writers.
+ *
+ * If flags & LDLM_FL_LOCAL_ONLY, throw the locks away without trying
+ * to notify the server. */
 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,
-                                    ldlm_cancel_flags_t flags,
-                                    void *opaque)
+                                   const struct ldlm_res_id *res_id,
+                                   ldlm_policy_data_t *policy,
+                                   ldlm_mode_t mode,
+                                   ldlm_cancel_flags_t flags,
+                                   void *opaque)
 {
-        struct ldlm_resource *res;
-        CFS_LIST_HEAD(cancels);
-        int count;
-        int rc;
-        ENTRY;
-
-        res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
-        if (res == NULL) {
-                /* This is not a problem. */
-                CDEBUG(D_INFO, "No resource "LPU64"\n", res_id->name[0]);
-                RETURN(0);
-        }
-
-        LDLM_RESOURCE_ADDREF(res);
-        count = ldlm_cancel_resource_local(res, &cancels, policy, mode,
-                                           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);
-
-        LDLM_RESOURCE_DELREF(res);
-        ldlm_resource_putref(res);
-        RETURN(0);
+       struct ldlm_resource *res;
+       struct list_head cancels = LIST_HEAD_INIT(cancels);
+       int count;
+       int rc;
+       ENTRY;
+
+       res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
+       if (IS_ERR(res)) {
+               /* This is not a problem. */
+               CDEBUG(D_INFO, "No resource "LPU64"\n", res_id->name[0]);
+               RETURN(0);
+       }
+
+       LDLM_RESOURCE_ADDREF(res);
+       count = ldlm_cancel_resource_local(res, &cancels, policy, mode,
+                                          0, flags | LCF_BL_AST, opaque);
+       rc = ldlm_cli_cancel_list(&cancels, count, NULL, flags);
+       if (rc != ELDLM_OK)
+               CERROR("canceling unused lock "DLDLMRES": rc = %d\n",
+                      PLDLMRES(res), rc);
+
+       LDLM_RESOURCE_DELREF(res);
+       ldlm_resource_putref(res);
+       RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_cli_cancel_unused_resource);
 
-static inline int have_no_nsresource(struct ldlm_namespace *ns)
-{
-        int no_resource = 0;
-
-        cfs_spin_lock(&ns->ns_hash_lock);
-        if (ns->ns_resources == 0)
-                no_resource = 1;
-        cfs_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,
+                                      struct hlist_node *hnode, void *arg)
+{
+       struct ldlm_resource           *res = cfs_hash_object(hs, hnode);
+       struct ldlm_cli_cancel_arg     *lc = arg;
+
+       ldlm_cli_cancel_unused_resource(ldlm_res_to_ns(res), &res->lr_name,
+                                       NULL, LCK_MINMODE, lc->lc_flags,
+                                       lc->lc_opaque);
+       /* must return 0 for hash iteration */
+       return 0;
 }
 
-/* Cancel all locks on a namespace (or a specific resource, if given)
+/**
+ * Cancel all locks on a namespace (or a specific resource, if given)
  * that have 0 readers/writers.
  *
  * If flags & LCF_LOCAL, throw the locks away without trying
@@ -1782,48 +1975,25 @@ int ldlm_cli_cancel_unused(struct ldlm_namespace *ns,
                            const struct ldlm_res_id *res_id,
                            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));
-
-        cfs_spin_lock(&ns->ns_hash_lock);
-        for (i = 0; i < RES_HASH_SIZE; i++) {
-                cfs_list_t *tmp;
-                tmp = ns->ns_hash[i].next;
-                while (tmp != &(ns->ns_hash[i])) {
-                        struct ldlm_resource *res;
-                        int rc;
-
-                        res = cfs_list_entry(tmp, struct ldlm_resource,
-                                             lr_hash);
-                        ldlm_resource_getref(res);
-                        cfs_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);
-                        cfs_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);
         }
-        cfs_spin_unlock(&ns->ns_hash_lock);
-
-        RETURN(ELDLM_OK);
 }
 
 /* Lock iterators. */
@@ -1831,7 +2001,7 @@ int ldlm_cli_cancel_unused(struct ldlm_namespace *ns,
 int ldlm_resource_foreach(struct ldlm_resource *res, ldlm_iterator_t iter,
                           void *closure)
 {
-        cfs_list_t *tmp, *next;
+       struct list_head *tmp, *next;
         struct ldlm_lock *lock;
         int rc = LDLM_ITER_CONTINUE;
 
@@ -1841,22 +2011,22 @@ int ldlm_resource_foreach(struct ldlm_resource *res, ldlm_iterator_t iter,
                 RETURN(LDLM_ITER_CONTINUE);
 
         lock_res(res);
-        cfs_list_for_each_safe(tmp, next, &res->lr_granted) {
-                lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
+       list_for_each_safe(tmp, next, &res->lr_granted) {
+               lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 
                 if (iter(lock, closure) == LDLM_ITER_STOP)
                         GOTO(out, rc = LDLM_ITER_STOP);
         }
 
-        cfs_list_for_each_safe(tmp, next, &res->lr_converting) {
-                lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
+       list_for_each_safe(tmp, next, &res->lr_converting) {
+               lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 
                 if (iter(lock, closure) == LDLM_ITER_STOP)
                         GOTO(out, rc = LDLM_ITER_STOP);
         }
 
-        cfs_list_for_each_safe(tmp, next, &res->lr_waiting) {
-                lock = cfs_list_entry(tmp, struct ldlm_lock, l_res_link);
+       list_for_each_safe(tmp, next, &res->lr_waiting) {
+               lock = list_entry(tmp, struct ldlm_lock, l_res_link);
 
                 if (iter(lock, closure) == LDLM_ITER_STOP)
                         GOTO(out, rc = LDLM_ITER_STOP);
@@ -1877,49 +2047,25 @@ 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)
-{
-        return ldlm_resource_foreach(res, ldlm_iter_helper, closure);
-}
+static int ldlm_res_iter_helper(cfs_hash_t *hs, cfs_hash_bd_t *bd,
+                               struct hlist_node *hnode, void *arg)
 
-int 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);
+        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_res(struct ldlm_namespace *ns,
-                               ldlm_res_iterator_t iter, void *closure)
+void ldlm_namespace_foreach(struct ldlm_namespace *ns,
+                            ldlm_iterator_t iter, void *closure)
+
 {
-        int i, rc = LDLM_ITER_CONTINUE;
-        struct ldlm_resource *res;
-        cfs_list_t *tmp;
+       struct iter_helper_data helper = { .iter = iter, .closure = closure };
+
+        cfs_hash_for_each_nolock(ns->ns_rs_hash,
+                                 ldlm_res_iter_helper, &helper);
 
-        ENTRY;
-        cfs_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 = cfs_list_entry(tmp, struct ldlm_resource,
-                                             lr_hash);
-                        ldlm_resource_getref(res);
-                        cfs_spin_unlock(&ns->ns_hash_lock);
-                        LDLM_RESOURCE_ADDREF(res);
-
-                        rc = iter(res, closure);
-
-                        LDLM_RESOURCE_DELREF(res);
-                        cfs_spin_lock(&ns->ns_hash_lock);
-                        tmp = tmp->next;
-                        ldlm_resource_putref_locked(res);
-                        if (rc == LDLM_ITER_STOP)
-                                GOTO(out, rc);
-                }
-        }
- out:
-        cfs_spin_unlock(&ns->ns_hash_lock);
-        RETURN(rc);
 }
 
 /* non-blocking function to manipulate a lock whose cb_data is being put away.
@@ -1928,37 +2074,35 @@ int ldlm_namespace_foreach_res(struct ldlm_namespace *ns,
  *       < 0:  errors
  */
 int ldlm_resource_iterate(struct ldlm_namespace *ns,
-                          const struct ldlm_res_id *res_id,
-                          ldlm_iterator_t iter, void *data)
+                         const struct ldlm_res_id *res_id,
+                         ldlm_iterator_t iter, void *data)
 {
-        struct ldlm_resource *res;
-        int rc;
-        ENTRY;
+       struct ldlm_resource *res;
+       int rc;
+       ENTRY;
 
-        if (ns == NULL) {
-                CERROR("must pass in namespace\n");
-                LBUG();
-        }
+       LASSERTF(ns != NULL, "must pass in namespace\n");
 
-        res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
-        if (res == NULL)
-                RETURN(0);
+       res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
+       if (IS_ERR(res))
+               RETURN(0);
 
-        LDLM_RESOURCE_ADDREF(res);
-        rc = ldlm_resource_foreach(res, iter, data);
-        LDLM_RESOURCE_DELREF(res);
-        ldlm_resource_putref(res);
-        RETURN(rc);
+       LDLM_RESOURCE_ADDREF(res);
+       rc = ldlm_resource_foreach(res, iter, data);
+       LDLM_RESOURCE_DELREF(res);
+       ldlm_resource_putref(res);
+       RETURN(rc);
 }
+EXPORT_SYMBOL(ldlm_resource_iterate);
 
 /* Lock replay */
 
 static int ldlm_chain_lock_for_replay(struct ldlm_lock *lock, void *closure)
 {
-        cfs_list_t *list = closure;
+       struct list_head *list = closure;
 
         /* we use l_pending_chain here, because it's unused on clients. */
-        LASSERTF(cfs_list_empty(&lock->l_pending_chain),
+       LASSERTF(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, or
@@ -1966,7 +2110,7 @@ static int ldlm_chain_lock_for_replay(struct ldlm_lock *lock, void *closure)
          * 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);
+               list_add(&lock->l_pending_chain, list);
                 LDLM_LOCK_GET(lock);
         }
 
@@ -1974,19 +2118,17 @@ static int ldlm_chain_lock_for_replay(struct ldlm_lock *lock, void *closure)
 }
 
 static int replay_lock_interpret(const struct lu_env *env,
-                                 struct ptlrpc_request *req,
-                                 struct ldlm_async_args *aa, int rc)
+                                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;
-        cfs_atomic_dec(&req->rq_import->imp_replay_inflight);
-        if (rc != ELDLM_OK)
-                GOTO(out, rc);
+       struct ldlm_lock     *lock;
+       struct ldlm_reply    *reply;
+       struct obd_export    *exp;
 
+       ENTRY;
+       atomic_dec(&req->rq_import->imp_replay_inflight);
+       if (rc != ELDLM_OK)
+               GOTO(out, rc);
 
         reply = req_capsule_server_get(&req->rq_pill, &RMF_DLM_REP);
         if (reply == NULL)
@@ -2002,22 +2144,26 @@ 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)
-                cfs_hash_rehash_key(exp->exp_lock_hash, &old_hash_key,
+        if (exp && exp->exp_lock_hash) {
+               /* In the function below, .hs_keycmp resolves to
+                * ldlm_export_lock_keycmp() */
+               /* coverity[overrun-buffer-val] */
+                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);
         LDLM_LOCK_PUT(lock);
 out:
         if (rc != ELDLM_OK)
-                ptlrpc_connect_import(req->rq_import, NULL);
+                ptlrpc_connect_import(req->rq_import);
 
         RETURN(rc);
 }
@@ -2032,7 +2178,7 @@ static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
 
 
         /* Bug 11974: Do not replay a lock which is actively being canceled */
-        if (lock->l_flags & LDLM_FL_CANCELING) {
+       if (ldlm_is_canceling(lock)) {
                 LDLM_DEBUG(lock, "Not replaying canceled lock:");
                 RETURN(0);
         }
@@ -2040,11 +2186,12 @@ static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
         /* If this is reply-less callback lock, we cannot replay it, since
          * server might have long dropped it, but notification of that event was
          * lost by network. (and server granted conflicting lock already) */
-        if (lock->l_flags & LDLM_FL_CANCEL_ON_BLOCK) {
+       if (ldlm_is_cancel_on_block(lock)) {
                 LDLM_DEBUG(lock, "Not replaying reply-less lock:");
                 ldlm_lock_cancel(lock);
                 RETURN(0);
         }
+
         /*
          * If granted mode matches the requested mode, this lock is granted.
          *
@@ -2063,7 +2210,7 @@ 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 (!cfs_list_empty(&lock->l_res_link))
+       else if (!list_empty(&lock->l_res_link))
                 flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_WAIT;
         else
                 flags = LDLM_FL_REPLAY;
@@ -2078,64 +2225,95 @@ static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
 
         body = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
         ldlm_lock2desc(lock, &body->lock_desc);
-        body->lock_flags = flags;
+       body->lock_flags = ldlm_flags_to_wire(flags);
 
         ldlm_lock2handle(lock, &body->lock_handle[0]);
-        if (lock->l_lvb_len != 0) {
-                req_capsule_extend(&req->rq_pill, &RQF_LDLM_ENQUEUE_LVB);
-                req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
-                                     lock->l_lvb_len);
-        }
+       if (lock->l_lvb_len > 0)
+               req_capsule_extend(&req->rq_pill, &RQF_LDLM_ENQUEUE_LVB);
+       req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
+                            lock->l_lvb_len);
         ptlrpc_request_set_replen(req);
         /* notify the server we've replayed all requests.
          * also, we mark the request to be put on a dedicated
          * queue to be processed after all request replayes.
          * bug 6063 */
-        lustre_msg_set_flags(req->rq_reqmsg, MSG_REQ_REPLAY_DONE);
+       lustre_msg_set_flags(req->rq_reqmsg, MSG_REQ_REPLAY_DONE);
 
-        LDLM_DEBUG(lock, "replaying lock:");
+       LDLM_DEBUG(lock, "replaying lock:");
 
-        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];
-        req->rq_interpret_reply = (ptlrpc_interpterer_t)replay_lock_interpret;
-        ptlrpcd_add_req(req, PSCOPE_OTHER);
+       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];
+       req->rq_interpret_reply = (ptlrpc_interpterer_t)replay_lock_interpret;
+       ptlrpcd_add_req(req, PDL_POLICY_LOCAL, -1);
 
-        RETURN(0);
+       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;
+       struct list_head cancels = LIST_HEAD_INIT(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;
-        CFS_LIST_HEAD(list);
-        struct ldlm_lock *lock, *next;
-        int rc = 0;
+       struct ldlm_namespace *ns = imp->imp_obd->obd_namespace;
+       struct list_head list = LIST_HEAD_INIT(list);
+       struct ldlm_lock *lock, *next;
+       int rc = 0;
 
-        ENTRY;
+       ENTRY;
 
-        LASSERT(cfs_atomic_read(&imp->imp_replay_inflight) == 0);
+       LASSERT(atomic_read(&imp->imp_replay_inflight) == 0);
 
-        /* don't replay locks if import failed recovery */
-        if (imp->imp_vbr_failed)
-                RETURN(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 */
-        cfs_atomic_inc(&imp->imp_replay_inflight);
+       /* ensure this doesn't fall to 0 before all have been queued */
+       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);
 
-        cfs_list_for_each_entry_safe(lock, next, &list, l_pending_chain) {
-                cfs_list_del_init(&lock->l_pending_chain);
-                if (rc) {
-                        LDLM_LOCK_PUT(lock);
-                        continue; /* or try to do the rest? */
-                }
-                rc = replay_one_lock(imp, lock);
-                LDLM_LOCK_PUT(lock);
-        }
+       ldlm_namespace_foreach(ns, ldlm_chain_lock_for_replay, &list);
 
-        cfs_atomic_dec(&imp->imp_replay_inflight);
+       list_for_each_entry_safe(lock, next, &list, l_pending_chain) {
+               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);
+       }
 
-        RETURN(rc);
+       atomic_dec(&imp->imp_replay_inflight);
+
+       RETURN(rc);
 }