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LU-3409 llite: silence lockdep warning in ll_md_blocking_ast
[fs/lustre-release.git] / lustre / ldlm / ldlm_flock.c
index 7ef1341..f59c354 100644 (file)
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
+/*
+ * GPL HEADER START
  *
- *  Copyright (c) 2002, 2003 Cluster File Systems, Inc.
- *   Author: Peter Braam <braam@clusterfs.com>
- *   Author: Phil Schwan <phil@clusterfs.com>
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
- *   This file is part of Lustre, http://www.lustre.org.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
  *
- *   Lustre is free software; you can redistribute it and/or
- *   modify it under the terms of version 2 of the GNU General Public
- *   License as published by the Free Software Foundation.
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
  *
- *   Lustre is distributed in the hope that it will be useful,
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *   GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  *
- *   You should have received a copy of the GNU General Public License
- *   along with Lustre; if not, write to the Free Software
- *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2003 Hewlett-Packard Development Company LP.
+ * Developed under the sponsorship of the US Government under
+ * Subcontract No. B514193
+ *
+ * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2010, 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ */
+
+/**
+ * This file implements POSIX lock type for Lustre.
+ * Its policy properties are start and end of extent and PID.
+ *
+ * These locks are only done through MDS due to POSIX semantics requiring
+ * e.g. that locks could be only partially released and as such split into
+ * two parts, and also that two adjacent locks from the same process may be
+ * merged into a single wider lock.
+ *
+ * Lock modes are mapped like this:
+ * PR and PW for READ and WRITE locks
+ * NL to request a releasing of a portion of the lock
+ *
+ * These flock locks never timeout.
  */
 
 #define DEBUG_SUBSYSTEM S_LDLM
 
 #ifdef __KERNEL__
-#include <linux/lustre_dlm.h>
-#include <linux/obd_support.h>
-#include <linux/obd_class.h>
-#include <linux/lustre_lib.h>
+#include <lustre_dlm.h>
+#include <obd_support.h>
+#include <obd_class.h>
+#include <lustre_lib.h>
+#include <libcfs/list.h>
 #else
 #include <liblustre.h>
+#include <obd_class.h>
 #endif
 
+#include "ldlm_internal.h"
+
+int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
+                            void *data, int flag);
+
+/**
+ * list_for_remaining_safe - iterate over the remaining entries in a list
+ *              and safeguard against removal of a list entry.
+ * \param pos   the &struct list_head to use as a loop counter. pos MUST
+ *              have been initialized prior to using it in this macro.
+ * \param n     another &struct list_head to use as temporary storage
+ * \param head  the head for your list.
+ */
+#define list_for_remaining_safe(pos, n, head) \
+        for (n = pos->next; pos != (head); pos = n, n = pos->next)
+
 static inline int
 ldlm_same_flock_owner(struct ldlm_lock *lock, struct ldlm_lock *new)
 {
-        if ((new->l_data.l_flock.pid == lock->l_data.l_flock.pid) &&
-            (new->l_export == lock->l_export))
-                return 1;
-        else
-                return 0;
+        return((new->l_policy_data.l_flock.owner ==
+                lock->l_policy_data.l_flock.owner) &&
+               (new->l_export == lock->l_export));
 }
 
 static inline int
 ldlm_flocks_overlap(struct ldlm_lock *lock, struct ldlm_lock *new)
 {
-        if ((new->l_data.l_flock.start <= lock->l_data.l_flock.end) &&
-            (new->l_data.l_flock.end >= lock->l_data.l_flock.start))
-                return 1;
-        else
-                return 0;
+        return((new->l_policy_data.l_flock.start <=
+                lock->l_policy_data.l_flock.end) &&
+               (new->l_policy_data.l_flock.end >=
+                lock->l_policy_data.l_flock.start));
+}
+
+static inline int ldlm_flock_blocking_link(struct ldlm_lock *req,
+                                          struct ldlm_lock *lock)
+{
+       int rc = 0;
+
+        /* For server only */
+        if (req->l_export == NULL)
+               return 0;
+
+       if (unlikely(req->l_export->exp_flock_hash == NULL)) {
+               rc = ldlm_init_flock_export(req->l_export);
+               if (rc)
+                       goto error;
+       }
+
+       LASSERT(cfs_hlist_unhashed(&req->l_exp_flock_hash));
+
+        req->l_policy_data.l_flock.blocking_owner =
+                lock->l_policy_data.l_flock.owner;
+        req->l_policy_data.l_flock.blocking_export =
+               lock->l_export;
+       req->l_policy_data.l_flock.blocking_refs = 0;
+
+       cfs_hash_add(req->l_export->exp_flock_hash,
+                    &req->l_policy_data.l_flock.owner,
+                    &req->l_exp_flock_hash);
+error:
+       return rc;
+}
+
+static inline void ldlm_flock_blocking_unlink(struct ldlm_lock *req)
+{
+        /* For server only */
+        if (req->l_export == NULL)
+                return;
+
+       check_res_locked(req->l_resource);
+       if (req->l_export->exp_flock_hash != NULL &&
+           !cfs_hlist_unhashed(&req->l_exp_flock_hash))
+               cfs_hash_del(req->l_export->exp_flock_hash,
+                            &req->l_policy_data.l_flock.owner,
+                            &req->l_exp_flock_hash);
 }
 
 static inline void
-ldlm_flock_destroy(struct ldlm_lock *lock, int flags)
+ldlm_flock_destroy(struct ldlm_lock *lock, ldlm_mode_t mode, __u64 flags)
 {
         ENTRY;
 
-        list_del_init(&lock->l_res_link);
-        if (flags == LDLM_FL_WAIT_NOREPROC) {
-                /* client side */
-                struct lustre_handle lockh;
+       LDLM_DEBUG(lock, "ldlm_flock_destroy(mode: %d, flags: 0x%llx)",
+                  mode, flags);
+
+       /* Safe to not lock here, since it should be empty anyway */
+       LASSERT(cfs_hlist_unhashed(&lock->l_exp_flock_hash));
 
-                /* Set a flag to prevent us from sending a CANCEL */
-                lock->l_flags |= LDLM_FL_LOCAL_ONLY;
+        cfs_list_del_init(&lock->l_res_link);
+        if (flags == LDLM_FL_WAIT_NOREPROC &&
+            !(lock->l_flags & LDLM_FL_FAILED)) {
+                /* client side - set a flag to prevent sending a CANCEL */
+                lock->l_flags |= LDLM_FL_LOCAL_ONLY | LDLM_FL_CBPENDING;
 
-                ldlm_lock2handle(lock, &lockh);
-                ldlm_lock_decref_and_cancel(&lockh, lock->l_granted_mode);
+                /* when reaching here, it is under lock_res_and_lock(). Thus,
+                   need call the nolock version of ldlm_lock_decref_internal*/
+                ldlm_lock_decref_internal_nolock(lock, mode);
         }
 
-        ldlm_lock_destroy(lock);
+        ldlm_lock_destroy_nolock(lock);
         EXIT;
 }
 
+/**
+ * POSIX locks deadlock detection code.
+ *
+ * Given a new lock \a req and an existing lock \a bl_lock it conflicts
+ * with, we need to iterate through all blocked POSIX locks for this
+ * export and see if there is a deadlock condition arising. (i.e. when
+ * one client holds a lock on something and want a lock on something
+ * else and at the same time another client has the opposite situation).
+ */
+static int
+ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock)
+{
+        struct obd_export *req_exp = req->l_export;
+        struct obd_export *bl_exp = bl_lock->l_export;
+        __u64 req_owner = req->l_policy_data.l_flock.owner;
+        __u64 bl_owner = bl_lock->l_policy_data.l_flock.owner;
+
+        /* For server only */
+        if (req_exp == NULL)
+                return 0;
+
+        class_export_get(bl_exp);
+       while (1) {
+               struct obd_export *bl_exp_new;
+               struct ldlm_lock *lock = NULL;
+               struct ldlm_flock *flock;
+
+               if (bl_exp->exp_flock_hash != NULL)
+                       lock = cfs_hash_lookup(bl_exp->exp_flock_hash,
+                                              &bl_owner);
+               if (lock == NULL)
+                       break;
+
+               flock = &lock->l_policy_data.l_flock;
+               LASSERT(flock->owner == bl_owner);
+                bl_owner = flock->blocking_owner;
+                bl_exp_new = class_export_get(flock->blocking_export);
+                class_export_put(bl_exp);
+
+               cfs_hash_put(bl_exp->exp_flock_hash, &lock->l_exp_flock_hash);
+                bl_exp = bl_exp_new;
+
+                if (bl_owner == req_owner && bl_exp == req_exp) {
+                        class_export_put(bl_exp);
+                        return 1;
+                }
+        }
+        class_export_put(bl_exp);
+
+        return 0;
+}
+
+/**
+ * Process a granting attempt for flock lock.
+ * Must be called under ns lock held.
+ *
+ * This function looks for any conflicts for \a lock in the granted or
+ * waiting queues. The lock is granted if no conflicts are found in
+ * either queue.
+ *
+ * It is also responsible for splitting a lock if a portion of the lock
+ * is released.
+ *
+ * If \a first_enq is 0 (ie, called from ldlm_reprocess_queue):
+ *   - blocking ASTs have already been sent
+ *
+ * If \a first_enq is 1 (ie, called from ldlm_lock_enqueue):
+ *   - blocking ASTs have not been sent yet, so list of conflicting locks
+ *     would be collected and ASTs sent.
+ */
 int
-ldlm_flock_enqueue(struct ldlm_lock **reqp, void *req_cookie, int *flags,
-                   int first_enq, ldlm_error_t *err)
+ldlm_process_flock_lock(struct ldlm_lock *req, __u64 *flags, int first_enq,
+                       ldlm_error_t *err, cfs_list_t *work_list)
 {
-        struct ldlm_lock *req = *reqp;
+        struct ldlm_resource *res = req->l_resource;
+        struct ldlm_namespace *ns = ldlm_res_to_ns(res);
+        cfs_list_t *tmp;
+        cfs_list_t *ownlocks = NULL;
+        struct ldlm_lock *lock = NULL;
         struct ldlm_lock *new = req;
         struct ldlm_lock *new2 = NULL;
-        struct ldlm_lock *lock = NULL;
-        struct ldlm_resource *res = req->l_resource;
-        struct ldlm_namespace *ns = res->lr_namespace;
-        struct list_head *tmp;
-        struct list_head *ownlocks;
         ldlm_mode_t mode = req->l_req_mode;
-        int added = 0;
+        int local = ns_is_client(ns);
+        int added = (mode == LCK_NL);
         int overlaps = 0;
+        int splitted = 0;
+        const struct ldlm_callback_suite null_cbs = { NULL };
+       int rc;
         ENTRY;
 
-        CDEBUG(D_FLOCK, "flags: 0x%x pid: %d mode: %d start: %llu end: %llu\n",
-               *flags, new->l_data.l_flock.pid, mode,
-               req->l_data.l_flock.start, req->l_data.l_flock.end);
+       CDEBUG(D_DLMTRACE, "flags %#llx owner "LPU64" pid %u mode %u start "
+              LPU64" end "LPU64"\n", *flags,
+              new->l_policy_data.l_flock.owner,
+               new->l_policy_data.l_flock.pid, mode,
+               req->l_policy_data.l_flock.start,
+               req->l_policy_data.l_flock.end);
 
         *err = ELDLM_OK;
 
-        /* No blocking ASTs are sent for record locks */
-        req->l_blocking_ast = NULL;
-
-        ownlocks = NULL;
-       if ((*flags == LDLM_FL_WAIT_NOREPROC) || (mode == LCK_NL)) {
-                list_for_each(tmp, &res->lr_granted) {
-                        lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+        if (local) {
+                /* No blocking ASTs are sent to the clients for
+                 * Posix file & record locks */
+                req->l_blocking_ast = NULL;
+        } else {
+                /* Called on the server for lock cancels. */
+                req->l_blocking_ast = ldlm_flock_blocking_ast;
+        }
 
+reprocess:
+        if ((*flags == LDLM_FL_WAIT_NOREPROC) || (mode == LCK_NL)) {
+                /* This loop determines where this processes locks start
+                 * in the resource lr_granted list. */
+                cfs_list_for_each(tmp, &res->lr_granted) {
+                        lock = cfs_list_entry(tmp, struct ldlm_lock,
+                                              l_res_link);
                         if (ldlm_same_flock_owner(lock, req)) {
                                 ownlocks = tmp;
                                 break;
                         }
                 }
         } else {
-                list_for_each(tmp, &res->lr_granted) {
-                        lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+                lockmode_verify(mode);
+
+                /* This loop determines if there are existing locks
+                 * that conflict with the new lock request. */
+                cfs_list_for_each(tmp, &res->lr_granted) {
+                        lock = cfs_list_entry(tmp, struct ldlm_lock,
+                                              l_res_link);
 
                         if (ldlm_same_flock_owner(lock, req)) {
                                 if (!ownlocks)
@@ -122,120 +308,141 @@ ldlm_flock_enqueue(struct ldlm_lock **reqp, void *req_cookie, int *flags,
                         /* locks are compatible, overlap doesn't matter */
                         if (lockmode_compat(lock->l_granted_mode, mode))
                                 continue;
-                        
+
                         if (!ldlm_flocks_overlap(lock, req))
                                 continue;
 
+                        if (!first_enq)
+                                RETURN(LDLM_ITER_CONTINUE);
+
                         if (*flags & LDLM_FL_BLOCK_NOWAIT) {
-                                ldlm_flock_destroy(req, *flags);
-                                *err = ELDLM_LOCK_ABORTED;
+                                ldlm_flock_destroy(req, mode, *flags);
+                                *err = -EAGAIN;
                                 RETURN(LDLM_ITER_STOP);
                         }
 
                         if (*flags & LDLM_FL_TEST_LOCK) {
-                                req->l_granted_mode = lock->l_granted_mode;
-                                req->l_data.l_flock.pid =
-                                        lock->l_data.l_flock.pid;
-                                req->l_data.l_flock.start =
-                                        lock->l_data.l_flock.start;
-                                req->l_data.l_flock.end =
-                                        lock->l_data.l_flock.end;
-                                ldlm_flock_destroy(req, *flags);
+                                ldlm_flock_destroy(req, mode, *flags);
+                                req->l_req_mode = lock->l_granted_mode;
+                                req->l_policy_data.l_flock.pid =
+                                        lock->l_policy_data.l_flock.pid;
+                                req->l_policy_data.l_flock.start =
+                                        lock->l_policy_data.l_flock.start;
+                                req->l_policy_data.l_flock.end =
+                                        lock->l_policy_data.l_flock.end;
+                                *flags |= LDLM_FL_LOCK_CHANGED;
                                 RETURN(LDLM_ITER_STOP);
                         }
 
-                        if (first_enq) {
-                                /* XXX - add deadlock detection check here */
+                        if (ldlm_flock_deadlock(req, lock)) {
+                                ldlm_flock_destroy(req, mode, *flags);
+                                *err = -EDEADLK;
+                                RETURN(LDLM_ITER_STOP);
                         }
 
+                       rc = ldlm_flock_blocking_link(req, lock);
+                       if (rc) {
+                               ldlm_flock_destroy(req, mode, *flags);
+                               *err = rc;
+                               RETURN(LDLM_ITER_STOP);
+                       }
+                        ldlm_resource_add_lock(res, &res->lr_waiting, req);
                         *flags |= LDLM_FL_BLOCK_GRANTED;
-                        RETURN(LDLM_ITER_CONTINUE);
+                        RETURN(LDLM_ITER_STOP);
                 }
         }
 
         if (*flags & LDLM_FL_TEST_LOCK) {
-                LASSERT(first_enq);
-                req->l_granted_mode = req->l_req_mode;
+                ldlm_flock_destroy(req, mode, *flags);
+                req->l_req_mode = LCK_NL;
+                *flags |= LDLM_FL_LOCK_CHANGED;
                 RETURN(LDLM_ITER_STOP);
         }
 
-        added = (mode == LCK_NL);
+        /* In case we had slept on this lock request take it off of the
+        * deadlock detection hash list. */
+        ldlm_flock_blocking_unlink(req);
 
-        /* Insert the new lock into the list */
+        /* Scan the locks owned by this process that overlap this request.
+         * We may have to merge or split existing locks. */
 
         if (!ownlocks)
                 ownlocks = &res->lr_granted;
 
-        for (tmp = ownlocks->next; ownlocks != &res->lr_granted;
-             ownlocks = tmp, tmp = ownlocks->next) {
-                lock = list_entry(ownlocks, struct ldlm_lock, l_res_link);
+        list_for_remaining_safe(ownlocks, tmp, &res->lr_granted) {
+                lock = cfs_list_entry(ownlocks, struct ldlm_lock, l_res_link);
 
                 if (!ldlm_same_flock_owner(lock, new))
                         break;
 
-               if (lock->l_granted_mode == mode) {
-                       if (lock->l_data.l_flock.end <
-                            (new->l_data.l_flock.start - 1))
-                               continue;
-
-                       if (lock->l_data.l_flock.start >
-                            (new->l_data.l_flock.end + 1))
-                               break;
-
-                       if (lock->l_data.l_flock.start >
-                            new->l_data.l_flock.start)
-                               lock->l_data.l_flock.start =
-                                        new->l_data.l_flock.start;
-                       else
-                               new->l_data.l_flock.start =
-                                        lock->l_data.l_flock.start;
-
-                       if (lock->l_data.l_flock.end <
-                            new->l_data.l_flock.end)
-                               lock->l_data.l_flock.end =
-                                        new->l_data.l_flock.end;
-                       else
-                               new->l_data.l_flock.end =
-                                        lock->l_data.l_flock.end;
-
-                       if (added) {
-                                ldlm_flock_destroy(lock, *flags);
-                       } else {
+                if (lock->l_granted_mode == mode) {
+                        /* If the modes are the same then we need to process
+                         * locks that overlap OR adjoin the new lock. The extra
+                         * logic condition is necessary to deal with arithmetic
+                         * overflow and underflow. */
+                        if ((new->l_policy_data.l_flock.start >
+                             (lock->l_policy_data.l_flock.end + 1))
+                            && (lock->l_policy_data.l_flock.end !=
+                                OBD_OBJECT_EOF))
+                                continue;
+
+                        if ((new->l_policy_data.l_flock.end <
+                             (lock->l_policy_data.l_flock.start - 1))
+                            && (lock->l_policy_data.l_flock.start != 0))
+                                break;
+
+                        if (new->l_policy_data.l_flock.start <
+                            lock->l_policy_data.l_flock.start) {
+                                lock->l_policy_data.l_flock.start =
+                                        new->l_policy_data.l_flock.start;
+                        } else {
+                                new->l_policy_data.l_flock.start =
+                                        lock->l_policy_data.l_flock.start;
+                        }
+
+                        if (new->l_policy_data.l_flock.end >
+                            lock->l_policy_data.l_flock.end) {
+                                lock->l_policy_data.l_flock.end =
+                                        new->l_policy_data.l_flock.end;
+                        } else {
+                                new->l_policy_data.l_flock.end =
+                                        lock->l_policy_data.l_flock.end;
+                        }
+
+                        if (added) {
+                                ldlm_flock_destroy(lock, mode, *flags);
+                        } else {
                                 new = lock;
                                 added = 1;
                         }
                         continue;
-               }
+                }
 
-                if (lock->l_data.l_flock.end < new->l_data.l_flock.start)
+                if (new->l_policy_data.l_flock.start >
+                    lock->l_policy_data.l_flock.end)
                         continue;
-                if (lock->l_data.l_flock.start > new->l_data.l_flock.end)
+
+                if (new->l_policy_data.l_flock.end <
+                    lock->l_policy_data.l_flock.start)
                         break;
 
                 ++overlaps;
 
-                if (new->l_data.l_flock.start <=
-                    lock->l_data.l_flock.start) {
-                        if (new->l_data.l_flock.end <
-                            lock->l_data.l_flock.end) {
-                                lock->l_data.l_flock.start =
-                                        new->l_data.l_flock.end + 1;
+                if (new->l_policy_data.l_flock.start <=
+                    lock->l_policy_data.l_flock.start) {
+                        if (new->l_policy_data.l_flock.end <
+                            lock->l_policy_data.l_flock.end) {
+                                lock->l_policy_data.l_flock.start =
+                                        new->l_policy_data.l_flock.end + 1;
                                 break;
-                        } else if (added) {
-                                ldlm_flock_destroy(lock, *flags);
-                        } else {
-                                lock->l_data.l_flock.start =
-                                        new->l_data.l_flock.start;
-                                lock->l_data.l_flock.end =
-                                        new->l_data.l_flock.end;
-                                new = lock;
-                                added = 1;
                         }
+                        ldlm_flock_destroy(lock, lock->l_req_mode, *flags);
                         continue;
                 }
-                if (new->l_data.l_flock.end >= lock->l_data.l_flock.end) {
-                        lock->l_data.l_flock.end =
-                                new->l_data.l_flock.start - 1;
+                if (new->l_policy_data.l_flock.end >=
+                    lock->l_policy_data.l_flock.end) {
+                        lock->l_policy_data.l_flock.end =
+                                new->l_policy_data.l_flock.start - 1;
                         continue;
                 }
 
@@ -245,131 +452,219 @@ ldlm_flock_enqueue(struct ldlm_lock **reqp, void *req_cookie, int *flags,
                  * allocating a new lock and use the req lock passed in
                  * with the request but this would complicate the reply
                  * processing since updates to req get reflected in the
-                 * reply. The client side must see the original lock data
-                 * so that it can process the unlock properly. */
-
-                /* XXX - if ldlm_lock_new() can sleep we have to
-                 * release the ns_lock, allocate the new lock, and
-                 * restart processing this lock. */
-                new2 = ldlm_lock_create(ns, NULL, res->lr_name, LDLM_FLOCK,
-                                        lock->l_granted_mode, NULL, NULL);
+                 * reply. The client side replays the lock request so
+                 * it must see the original lock data in the reply. */
+
+                /* XXX - if ldlm_lock_new() can sleep we should
+                 * release the lr_lock, allocate the new lock,
+                 * and restart processing this lock. */
                 if (!new2) {
-                        /* LBUG for now */
-                        LASSERT(0);
-                        RETURN(ENOMEM);
+                        unlock_res_and_lock(req);
+                       new2 = ldlm_lock_create(ns, &res->lr_name, LDLM_FLOCK,
+                                               lock->l_granted_mode, &null_cbs,
+                                               NULL, 0, LVB_T_NONE);
+                        lock_res_and_lock(req);
+                        if (!new2) {
+                                ldlm_flock_destroy(req, lock->l_granted_mode,
+                                                   *flags);
+                                *err = -ENOLCK;
+                                RETURN(LDLM_ITER_STOP);
+                        }
+                        goto reprocess;
                 }
 
+                splitted = 1;
+
                 new2->l_granted_mode = lock->l_granted_mode;
-                new2->l_data.l_flock.pid = new->l_data.l_flock.pid;
-                new2->l_data.l_flock.start = lock->l_data.l_flock.start;
-                new2->l_data.l_flock.end = new->l_data.l_flock.start - 1;
-                lock->l_data.l_flock.start = new->l_data.l_flock.end + 1;
-                new2->l_connh = lock->l_connh;
-                if ((new2->l_export = lock->l_export) != NULL) {
-                        list_add(&new2->l_export_chain,
-                                 &new2->l_export->
-                                 exp_ldlm_data.led_held_locks);
-                }
-                if (*flags == LDLM_FL_WAIT_NOREPROC) {
-                        /* client side */
-                        ldlm_lock_addref_internal(new2, lock->l_granted_mode);
+                new2->l_policy_data.l_flock.pid =
+                        new->l_policy_data.l_flock.pid;
+                new2->l_policy_data.l_flock.owner =
+                        new->l_policy_data.l_flock.owner;
+                new2->l_policy_data.l_flock.start =
+                        lock->l_policy_data.l_flock.start;
+                new2->l_policy_data.l_flock.end =
+                        new->l_policy_data.l_flock.start - 1;
+                lock->l_policy_data.l_flock.start =
+                        new->l_policy_data.l_flock.end + 1;
+                new2->l_conn_export = lock->l_conn_export;
+                if (lock->l_export != NULL) {
+                        new2->l_export = class_export_lock_get(lock->l_export, new2);
+                        if (new2->l_export->exp_lock_hash &&
+                            cfs_hlist_unhashed(&new2->l_exp_hash))
+                                cfs_hash_add(new2->l_export->exp_lock_hash,
+                                             &new2->l_remote_handle,
+                                             &new2->l_exp_hash);
                 }
+                if (*flags == LDLM_FL_WAIT_NOREPROC)
+                        ldlm_lock_addref_internal_nolock(new2,
+                                                         lock->l_granted_mode);
 
                 /* insert new2 at lock */
-                list_add_tail(&new2->l_res_link, ownlocks);
-                LDLM_LOCK_PUT(new2);
+                ldlm_resource_add_lock(res, ownlocks, new2);
+                LDLM_LOCK_RELEASE(new2);
                 break;
         }
 
-        if (added) {
-                ldlm_flock_destroy(req, *flags);
-        } else {
-                /* insert new at ownlocks */
-                new->l_granted_mode = new->l_req_mode;
-                list_del_init(&new->l_res_link);
-                list_add_tail(&new->l_res_link, ownlocks);
-        }
+        /* if new2 is created but never used, destroy it*/
+        if (splitted == 0 && new2 != NULL)
+                ldlm_lock_destroy_nolock(new2);
+
+        /* At this point we're granting the lock request. */
+        req->l_granted_mode = req->l_req_mode;
 
-       if (*flags != LDLM_FL_WAIT_NOREPROC) {
-                if (req->l_completion_ast)
-                        ldlm_add_ast_work_item(req, NULL, NULL, 0);
-
-                /* The only problem with doing the reprocessing here is that
-                 * the completion ASTs for newly granted locks will be sent
-                 * before the unlock completion is sent. It shouldn't be an
-                 * issue. Also note that ldlm_flock_enqueue() will recurse,
-                 * but only once because there can't be unlock requests on
-                 * the wait queue. */
-                if ((mode == LCK_NL) && overlaps)
-                        ldlm_reprocess_queue(res, &res->lr_waiting);
+        /* Add req to the granted queue before calling ldlm_reprocess_all(). */
+        if (!added) {
+                cfs_list_del_init(&req->l_res_link);
+                /* insert new lock before ownlocks in list. */
+                ldlm_resource_add_lock(res, ownlocks, req);
         }
 
-        ldlm_resource_dump(res);
+        if (*flags != LDLM_FL_WAIT_NOREPROC) {
+#ifdef HAVE_SERVER_SUPPORT
+                if (first_enq) {
+                        /* If this is an unlock, reprocess the waitq and
+                         * send completions ASTs for locks that can now be
+                         * granted. The only problem with doing this
+                         * reprocessing here is that the completion ASTs for
+                         * newly granted locks will be sent before the unlock
+                         * completion is sent. It shouldn't be an issue. Also
+                         * note that ldlm_process_flock_lock() will recurse,
+                         * but only once because first_enq will be false from
+                         * ldlm_reprocess_queue. */
+                        if ((mode == LCK_NL) && overlaps) {
+                                CFS_LIST_HEAD(rpc_list);
+                                int rc;
+restart:
+                                ldlm_reprocess_queue(res, &res->lr_waiting,
+                                                     &rpc_list);
+
+                                unlock_res_and_lock(req);
+                                rc = ldlm_run_ast_work(ns, &rpc_list,
+                                                       LDLM_WORK_CP_AST);
+                                lock_res_and_lock(req);
+                                if (rc == -ERESTART)
+                                        GOTO(restart, -ERESTART);
+                       }
+                } else {
+                        LASSERT(req->l_completion_ast);
+                        ldlm_add_ast_work_item(req, NULL, work_list);
+                }
+#else /* !HAVE_SERVER_SUPPORT */
+                /* The only one possible case for client-side calls flock
+                 * policy function is ldlm_flock_completion_ast inside which
+                 * carries LDLM_FL_WAIT_NOREPROC flag. */
+                CERROR("Illegal parameter for client-side-only module.\n");
+                LBUG();
+#endif /* HAVE_SERVER_SUPPORT */
+        }
 
-       RETURN(LDLM_ITER_CONTINUE);
-}
+       /* In case we're reprocessing the requested lock we can't destroy
+        * it until after calling ldlm_add_ast_work_item() above so that laawi()
+        * can bump the reference count on \a req. Otherwise \a req
+        * could be freed before the completion AST can be sent.  */
+        if (added)
+                ldlm_flock_destroy(req, mode, *flags);
 
-static void interrupted_flock_completion_wait(void *data)
-{
+        ldlm_resource_dump(D_INFO, res);
+        RETURN(LDLM_ITER_CONTINUE);
 }
 
-struct flock_wait_data {
+struct ldlm_flock_wait_data {
         struct ldlm_lock *fwd_lock;
         int               fwd_generation;
 };
 
-int
-ldlm_flock_completion_ast(struct ldlm_lock *lock, int flags, void *data)
+static void
+ldlm_flock_interrupted_wait(void *data)
 {
-        struct ldlm_namespace *ns;
-        struct file_lock *getlk = data;
-        struct flock_wait_data fwd;
-        unsigned long irqflags;
-        struct obd_device *obd;
-        struct obd_import *imp = NULL;
-        ldlm_error_t err;
-        int rc = 0;
-        struct l_wait_info lwi;
+        struct ldlm_lock *lock;
         ENTRY;
 
-        LASSERT(flags != LDLM_FL_WAIT_NOREPROC);
+        lock = ((struct ldlm_flock_wait_data *)data)->fwd_lock;
+
+       /* take lock off the deadlock detection hash list. */
+       lock_res_and_lock(lock);
+        ldlm_flock_blocking_unlink(lock);
+
+       /* client side - set flag to prevent lock from being put on LRU list */
+        lock->l_flags |= LDLM_FL_CBPENDING;
+        unlock_res_and_lock(lock);
+
+        EXIT;
+}
+
+/**
+ * Flock completion callback function.
+ *
+ * \param lock [in,out]: A lock to be handled
+ * \param flags    [in]: flags
+ * \param *data    [in]: ldlm_work_cp_ast_lock() will use ldlm_cb_set_arg
+ *
+ * \retval 0    : success
+ * \retval <0   : failure
+ */
+int
+ldlm_flock_completion_ast(struct ldlm_lock *lock, __u64 flags, void *data)
+{
+       struct file_lock                *getlk = lock->l_ast_data;
+        struct obd_device              *obd;
+        struct obd_import              *imp = NULL;
+        struct ldlm_flock_wait_data     fwd;
+        struct l_wait_info              lwi;
+        ldlm_error_t                    err;
+        int                             rc = 0;
+        ENTRY;
 
-        if (flags == 0) {
-                wake_up(&lock->l_waitq);
+       CDEBUG(D_DLMTRACE, "flags: 0x%llx data: %p getlk: %p\n",
+               flags, data, getlk);
+
+        /* Import invalidation. We need to actually release the lock
+         * references being held, so that it can go away. No point in
+         * holding the lock even if app still believes it has it, since
+         * server already dropped it anyway. Only for granted locks too. */
+        if ((lock->l_flags & (LDLM_FL_FAILED|LDLM_FL_LOCAL_ONLY)) ==
+            (LDLM_FL_FAILED|LDLM_FL_LOCAL_ONLY)) {
+                if (lock->l_req_mode == lock->l_granted_mode &&
+                    lock->l_granted_mode != LCK_NL &&
+                    NULL == data)
+                        ldlm_lock_decref_internal(lock, lock->l_req_mode);
+
+                /* Need to wake up the waiter if we were evicted */
+                cfs_waitq_signal(&lock->l_waitq);
                 RETURN(0);
         }
 
+        LASSERT(flags != LDLM_FL_WAIT_NOREPROC);
+
         if (!(flags & (LDLM_FL_BLOCK_WAIT | LDLM_FL_BLOCK_GRANTED |
-                       LDLM_FL_BLOCK_CONV)))
-                goto  granted;
+                       LDLM_FL_BLOCK_CONV))) {
+                if (NULL == data)
+                        /* mds granted the lock in the reply */
+                        goto granted;
+                /* CP AST RPC: lock get granted, wake it up */
+                cfs_waitq_signal(&lock->l_waitq);
+                RETURN(0);
+        }
 
         LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
                    "sleeping");
-
-        ldlm_lock_dump(D_OTHER, lock);
-
         fwd.fwd_lock = lock;
-        obd = class_conn2obd(lock->l_connh);
+        obd = class_exp2obd(lock->l_conn_export);
 
-        /* if this is a local lock, then there is no import */
-        if (obd != NULL)
+        /* if this is a local lock, there is no import */
+        if (NULL != obd)
                 imp = obd->u.cli.cl_import;
 
-        if (imp != NULL) {
-                spin_lock_irqsave(&imp->imp_lock, irqflags);
-                fwd.fwd_generation = imp->imp_generation;
-                spin_unlock_irqrestore(&imp->imp_lock, irqflags);
+        if (NULL != imp) {
+               spin_lock(&imp->imp_lock);
+               fwd.fwd_generation = imp->imp_generation;
+               spin_unlock(&imp->imp_lock);
         }
 
-        lwi = LWI_TIMEOUT_INTR(0, NULL, interrupted_flock_completion_wait,
-                               &fwd);
+        lwi = LWI_TIMEOUT_INTR(0, NULL, ldlm_flock_interrupted_wait, &fwd);
 
         /* Go to sleep until the lock is granted. */
-        rc = l_wait_event(lock->l_waitq,
-                          ((lock->l_req_mode == lock->l_granted_mode) ||
-                           lock->l_destroyed), &lwi);
-
-        LASSERT(!(lock->l_destroyed));
+        rc = l_wait_event(lock->l_waitq, is_granted_or_cancelled(lock), &lwi);
 
         if (rc) {
                 LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
@@ -378,41 +673,213 @@ ldlm_flock_completion_ast(struct ldlm_lock *lock, int flags, void *data)
         }
 
 granted:
+        OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT, 10);
 
-        LDLM_DEBUG(lock, "client-side enqueue waking up");
-        ns = lock->l_resource->lr_namespace;
-        l_lock(&ns->ns_lock);
+        if (lock->l_destroyed) {
+                LDLM_DEBUG(lock, "client-side enqueue waking up: destroyed");
+                RETURN(0);
+        }
+
+        if (lock->l_flags & LDLM_FL_FAILED) {
+                LDLM_DEBUG(lock, "client-side enqueue waking up: failed");
+                RETURN(-EIO);
+        }
+
+        if (rc) {
+                LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
+                           rc);
+                RETURN(rc);
+        }
+
+        LDLM_DEBUG(lock, "client-side enqueue granted");
+
+       lock_res_and_lock(lock);
+
+       /* take lock off the deadlock detection hash list. */
+        ldlm_flock_blocking_unlink(lock);
 
         /* ldlm_lock_enqueue() has already placed lock on the granted list. */
-        list_del_init(&lock->l_res_link);
+        cfs_list_del_init(&lock->l_res_link);
 
-        if (getlk) {
+        if (flags & LDLM_FL_TEST_LOCK) {
                 /* fcntl(F_GETLK) request */
-                if (lock->l_granted_mode == LCK_PR)
-                        getlk->fl_type = F_RDLCK;
-                else if (lock->l_granted_mode == LCK_PW)
-                        getlk->fl_type = F_WRLCK;
-                else
-                        getlk->fl_type = F_UNLCK;
-                getlk->fl_pid = lock->l_data.l_flock.pid;
-                getlk->fl_start = lock->l_data.l_flock.start;
-                getlk->fl_end = lock->l_data.l_flock.end;
-                /* ldlm_flock_destroy(lock); */
-        } else {
-                flags = LDLM_FL_WAIT_NOREPROC;
-                /* We need to reprocess the lock to do merges or split */
-                ldlm_flock_enqueue(&lock, NULL, &flags, 1, &err);
-        }
-        l_unlock(&ns->ns_lock);
-        RETURN(0);
+                /* The old mode was saved in getlk->fl_type so that if the mode
+                 * in the lock changes we can decref the appropriate refcount.*/
+               ldlm_flock_destroy(lock, flock_type(getlk),
+                                  LDLM_FL_WAIT_NOREPROC);
+               switch (lock->l_granted_mode) {
+               case LCK_PR:
+                       flock_set_type(getlk, F_RDLCK);
+                       break;
+               case LCK_PW:
+                       flock_set_type(getlk, F_WRLCK);
+                       break;
+               default:
+                       flock_set_type(getlk, F_UNLCK);
+               }
+               flock_set_pid(getlk, (pid_t)lock->l_policy_data.l_flock.pid);
+               flock_set_start(getlk,
+                               (loff_t)lock->l_policy_data.l_flock.start);
+               flock_set_end(getlk,
+                             (loff_t)lock->l_policy_data.l_flock.end);
+       } else {
+               __u64 noreproc = LDLM_FL_WAIT_NOREPROC;
+
+               /* We need to reprocess the lock to do merges or splits
+                * with existing locks owned by this process. */
+               ldlm_process_flock_lock(lock, &noreproc, 1, &err, NULL);
+       }
+       unlock_res_and_lock(lock);
+       RETURN(0);
 }
+EXPORT_SYMBOL(ldlm_flock_completion_ast);
 
-/* This function is only called on the client when a lock is aborted. */
-int
-ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *ld,
-                        void *data, int flag)
+int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
+                            void *data, int flag)
 {
         ENTRY;
-        ldlm_lock_destroy(lock);
+
+        LASSERT(lock);
+        LASSERT(flag == LDLM_CB_CANCELING);
+
+       /* take lock off the deadlock detection hash list. */
+       lock_res_and_lock(lock);
+        ldlm_flock_blocking_unlink(lock);
+       unlock_res_and_lock(lock);
         RETURN(0);
 }
+
+void ldlm_flock_policy_wire18_to_local(const ldlm_wire_policy_data_t *wpolicy,
+                                       ldlm_policy_data_t *lpolicy)
+{
+        memset(lpolicy, 0, sizeof(*lpolicy));
+        lpolicy->l_flock.start = wpolicy->l_flock.lfw_start;
+        lpolicy->l_flock.end = wpolicy->l_flock.lfw_end;
+        lpolicy->l_flock.pid = wpolicy->l_flock.lfw_pid;
+        /* Compat code, old clients had no idea about owner field and
+         * relied solely on pid for ownership. Introduced in LU-104, 2.1,
+         * April 2011 */
+        lpolicy->l_flock.owner = wpolicy->l_flock.lfw_pid;
+}
+
+
+void ldlm_flock_policy_wire21_to_local(const ldlm_wire_policy_data_t *wpolicy,
+                                       ldlm_policy_data_t *lpolicy)
+{
+        memset(lpolicy, 0, sizeof(*lpolicy));
+        lpolicy->l_flock.start = wpolicy->l_flock.lfw_start;
+        lpolicy->l_flock.end = wpolicy->l_flock.lfw_end;
+        lpolicy->l_flock.pid = wpolicy->l_flock.lfw_pid;
+        lpolicy->l_flock.owner = wpolicy->l_flock.lfw_owner;
+}
+
+void ldlm_flock_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
+                                     ldlm_wire_policy_data_t *wpolicy)
+{
+        memset(wpolicy, 0, sizeof(*wpolicy));
+        wpolicy->l_flock.lfw_start = lpolicy->l_flock.start;
+        wpolicy->l_flock.lfw_end = lpolicy->l_flock.end;
+        wpolicy->l_flock.lfw_pid = lpolicy->l_flock.pid;
+        wpolicy->l_flock.lfw_owner = lpolicy->l_flock.owner;
+}
+
+/*
+ * Export handle<->flock hash operations.
+ */
+static unsigned
+ldlm_export_flock_hash(cfs_hash_t *hs, const void *key, unsigned mask)
+{
+       return cfs_hash_u64_hash(*(__u64 *)key, mask);
+}
+
+static void *
+ldlm_export_flock_key(cfs_hlist_node_t *hnode)
+{
+       struct ldlm_lock *lock;
+
+       lock = cfs_hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
+       return &lock->l_policy_data.l_flock.owner;
+}
+
+static int
+ldlm_export_flock_keycmp(const void *key, cfs_hlist_node_t *hnode)
+{
+       return !memcmp(ldlm_export_flock_key(hnode), key, sizeof(__u64));
+}
+
+static void *
+ldlm_export_flock_object(cfs_hlist_node_t *hnode)
+{
+       return cfs_hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
+}
+
+static void
+ldlm_export_flock_get(cfs_hash_t *hs, cfs_hlist_node_t *hnode)
+{
+       struct ldlm_lock *lock;
+       struct ldlm_flock *flock;
+
+       lock = cfs_hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
+       LDLM_LOCK_GET(lock);
+
+       flock = &lock->l_policy_data.l_flock;
+       LASSERT(flock->blocking_export != NULL);
+       class_export_get(flock->blocking_export);
+       flock->blocking_refs++;
+}
+
+static void
+ldlm_export_flock_put(cfs_hash_t *hs, cfs_hlist_node_t *hnode)
+{
+       struct ldlm_lock *lock;
+       struct ldlm_flock *flock;
+
+       lock = cfs_hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
+       LDLM_LOCK_RELEASE(lock);
+
+       flock = &lock->l_policy_data.l_flock;
+       LASSERT(flock->blocking_export != NULL);
+       class_export_put(flock->blocking_export);
+       if (--flock->blocking_refs == 0) {
+               flock->blocking_owner = 0;
+               flock->blocking_export = NULL;
+       }
+}
+
+static cfs_hash_ops_t ldlm_export_flock_ops = {
+       .hs_hash        = ldlm_export_flock_hash,
+       .hs_key         = ldlm_export_flock_key,
+       .hs_keycmp      = ldlm_export_flock_keycmp,
+       .hs_object      = ldlm_export_flock_object,
+       .hs_get         = ldlm_export_flock_get,
+       .hs_put         = ldlm_export_flock_put,
+       .hs_put_locked  = ldlm_export_flock_put,
+};
+
+int ldlm_init_flock_export(struct obd_export *exp)
+{
+       exp->exp_flock_hash =
+               cfs_hash_create(obd_uuid2str(&exp->exp_client_uuid),
+                               HASH_EXP_LOCK_CUR_BITS,
+                               HASH_EXP_LOCK_MAX_BITS,
+                               HASH_EXP_LOCK_BKT_BITS, 0,
+                               CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
+                               &ldlm_export_flock_ops,
+                               CFS_HASH_DEFAULT | CFS_HASH_NBLK_CHANGE);
+       if (!exp->exp_flock_hash)
+               RETURN(-ENOMEM);
+
+       RETURN(0);
+}
+EXPORT_SYMBOL(ldlm_init_flock_export);
+
+void ldlm_destroy_flock_export(struct obd_export *exp)
+{
+       ENTRY;
+       if (exp->exp_flock_hash) {
+               cfs_hash_putref(exp->exp_flock_hash);
+               exp->exp_flock_hash = NULL;
+       }
+       EXIT;
+}
+EXPORT_SYMBOL(ldlm_destroy_flock_export);