Whamcloud - gitweb
LU-10467 ldlm: convert waiting in ldlm_flock_completion_ast()
[fs/lustre-release.git] / lustre / ldlm / ldlm_flock.c
index 4090ae0..b76638b 100644 (file)
  *
  * 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
- *
- * 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.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2010, 2011, Whamcloud, Inc.
+ * Copyright (c) 2010, 2017, 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/list.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"
 
-#define l_flock_waitq   l_lru
-
 int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
-                            void *data, int flag);
+                           void *data, int flag);
 
 /**
  * list_for_remaining_safe - iterate over the remaining entries in a list
@@ -67,481 +72,565 @@ int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
  * \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)
+       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)
 {
-        return((new->l_policy_data.l_flock.owner ==
-                lock->l_policy_data.l_flock.owner) &&
-               (new->l_export == lock->l_export));
+       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)
 {
-        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));
+       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 void ldlm_flock_blocking_link(struct ldlm_lock *req,
-                                            struct ldlm_lock *lock)
+                                           struct ldlm_lock *lock)
 {
-        /* For server only */
-        if (req->l_export == NULL)
-                return;
+       /* For server only */
+       if (req->l_export == NULL)
+               return;
 
-        LASSERT(cfs_list_empty(&req->l_flock_waitq));
-        cfs_write_lock(&req->l_export->exp_flock_wait_lock);
+       LASSERT(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 =
-                class_export_get(lock->l_export);
+       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;
+       atomic_set(&req->l_policy_data.l_flock.blocking_refs, 0);
 
-        cfs_list_add_tail(&req->l_flock_waitq,
-                          &req->l_export->exp_flock_wait_list);
-        cfs_write_unlock(&req->l_export->exp_flock_wait_lock);
+       cfs_hash_add(req->l_export->exp_flock_hash,
+                    &req->l_policy_data.l_flock.owner,
+                    &req->l_exp_flock_hash);
 }
 
 static inline void ldlm_flock_blocking_unlink(struct ldlm_lock *req)
 {
-        /* For server only */
-        if (req->l_export == NULL)
-                return;
-
-        cfs_write_lock(&req->l_export->exp_flock_wait_lock);
-        if (!cfs_list_empty(&req->l_flock_waitq)) {
-                cfs_list_del_init(&req->l_flock_waitq);
-
-                class_export_put(req->l_policy_data.l_flock.blocking_export);
-                req->l_policy_data.l_flock.blocking_owner = 0;
-                req->l_policy_data.l_flock.blocking_export = NULL;
-        }
-        cfs_write_unlock(&req->l_export->exp_flock_wait_lock);
+       /* For server only */
+       if (req->l_export == NULL)
+               return;
+
+       check_res_locked(req->l_resource);
+       if (req->l_export->exp_flock_hash != NULL &&
+           !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, ldlm_mode_t mode, int flags)
+ldlm_flock_destroy(struct ldlm_lock *lock, enum ldlm_mode mode, __u64 flags)
 {
-        ENTRY;
+       ENTRY;
 
-        LDLM_DEBUG(lock, "ldlm_flock_destroy(mode: %d, flags: 0x%x)",
-                   mode, flags);
+       LDLM_DEBUG(lock, "ldlm_flock_destroy(mode: %d, flags: %#llx)",
+                  mode, flags);
 
-        /* Safe to not lock here, since it should be empty anyway */
-        LASSERT(cfs_list_empty(&lock->l_flock_waitq));
+       /* Safe to not lock here, since it should be empty anyway */
+       LASSERT(hlist_unhashed(&lock->l_exp_flock_hash));
 
-        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;
+       list_del_init(&lock->l_res_link);
+       if (flags == LDLM_FL_WAIT_NOREPROC) {
+               /* client side - set a flag to prevent sending a CANCEL */
+               lock->l_flags |= LDLM_FL_LOCAL_ONLY | LDLM_FL_CBPENDING;
 
-                /* 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);
-        }
+               /* 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_nolock(lock);
-        EXIT;
+       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).
+ */
+
+struct ldlm_flock_lookup_cb_data {
+       __u64 *bl_owner;
+       struct ldlm_lock *lock;
+       struct obd_export *exp;
+};
+
+static int ldlm_flock_lookup_cb(struct cfs_hash *hs, struct cfs_hash_bd *bd,
+                               struct hlist_node *hnode, void *data)
+{
+       struct ldlm_flock_lookup_cb_data *cb_data = data;
+       struct obd_export *exp = cfs_hash_object(hs, hnode);
+       struct ldlm_lock *lock;
+
+       lock = cfs_hash_lookup(exp->exp_flock_hash, cb_data->bl_owner);
+       if (lock == NULL)
+               return 0;
+
+       /* Stop on first found lock. Same process can't sleep twice */
+       cb_data->lock = lock;
+       cb_data->exp = class_export_get(exp);
+
+       return 1;
 }
 
 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;
-        struct obd_export *bl_exp_new;
-        __u64 req_owner = req->l_policy_data.l_flock.owner;
-        __u64 bl_owner = bl_lock->l_policy_data.l_flock.owner;
-        struct ldlm_lock *lock;
-
-        /* For server only */
-        if (req_exp == NULL)
-                return 0;
-
-        class_export_get(bl_exp);
-restart:
-        cfs_read_lock(&bl_exp->exp_flock_wait_lock);
-        cfs_list_for_each_entry(lock, &bl_exp->exp_flock_wait_list,
-                                l_flock_waitq) {
-                struct ldlm_flock *flock = &lock->l_policy_data.l_flock;
-
-                /* want to find something from same client and same process */
-                if (flock->owner != bl_owner)
-                        continue;
-
-                bl_owner = flock->blocking_owner;
-                bl_exp_new = class_export_get(flock->blocking_export);
-                cfs_read_unlock(&bl_exp->exp_flock_wait_lock);
-                class_export_put(bl_exp);
-                bl_exp = bl_exp_new;
-
-                if (bl_owner == req_owner && bl_exp == req_exp) {
-                        class_export_put(bl_exp);
-                        return 1;
-                }
-
-                goto restart;
-        }
-        cfs_read_unlock(&bl_exp->exp_flock_wait_lock);
-        class_export_put(bl_exp);
-
-        return 0;
+       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 ldlm_flock_lookup_cb_data cb_data = {
+                       .bl_owner = &bl_owner,
+                       .lock = NULL,
+                       .exp = NULL,
+               };
+               struct obd_export *bl_exp_new;
+               struct ldlm_lock *lock = NULL;
+               struct ldlm_flock *flock;
+
+               if (bl_exp->exp_flock_hash != NULL) {
+                       cfs_hash_for_each_key(
+                               bl_exp->exp_obd->obd_nid_hash,
+                               &bl_exp->exp_connection->c_peer.nid,
+                               ldlm_flock_lookup_cb, &cb_data);
+                       lock = cb_data.lock;
+               }
+               if (lock == NULL)
+                       break;
+
+               class_export_put(bl_exp);
+               bl_exp = cb_data.exp;
+
+               LASSERT(req != lock);
+               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_exp->exp_failed)
+                       break;
+
+               if (bl_owner == req_owner &&
+                   (bl_exp->exp_connection->c_peer.nid ==
+                    req_exp->exp_connection->c_peer.nid)) {
+                       class_export_put(bl_exp);
+                       return 1;
+               }
+       }
+       class_export_put(bl_exp);
+
+       return 0;
 }
 
+static void ldlm_flock_cancel_on_deadlock(struct ldlm_lock *lock,
+                                         struct list_head *work_list)
+{
+       CDEBUG(D_INFO, "reprocess deadlock req=%p\n", lock);
+
+       if ((exp_connect_flags(lock->l_export) &
+            OBD_CONNECT_FLOCK_DEAD) == 0) {
+               CERROR("deadlock found, but client doesn't support flock canceliation\n");
+       } else {
+               LASSERT(lock->l_completion_ast);
+               LASSERT(!ldlm_is_ast_sent(lock));
+               lock->l_flags |= (LDLM_FL_AST_SENT | LDLM_FL_CANCEL_ON_BLOCK |
+                                 LDLM_FL_FLOCK_DEADLOCK);
+               ldlm_flock_blocking_unlink(lock);
+               ldlm_resource_unlink_lock(lock);
+               ldlm_add_ast_work_item(lock, NULL, work_list);
+       }
+}
+
+/**
+ * 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.
+ */
 int
-ldlm_process_flock_lock(struct ldlm_lock *req, int *flags, int first_enq,
-                        ldlm_error_t *err, cfs_list_t *work_list)
+ldlm_process_flock_lock(struct ldlm_lock *req, __u64 *flags,
+                       enum ldlm_process_intention intention,
+                       enum ldlm_error *err, struct list_head *work_list)
 {
-        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;
-        ldlm_mode_t mode = req->l_req_mode;
-        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 };
-        ENTRY;
-
-        CDEBUG(D_DLMTRACE, "flags %#x 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;
-
-        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;
-        }
+       struct ldlm_resource *res = req->l_resource;
+       struct ldlm_namespace *ns = ldlm_res_to_ns(res);
+       struct list_head *tmp;
+       struct list_head *ownlocks = NULL;
+       struct ldlm_lock *lock = NULL;
+       struct ldlm_lock *new = req;
+       struct ldlm_lock *new2 = NULL;
+       enum ldlm_mode mode = req->l_req_mode;
+       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 };
+       struct list_head *grant_work = (intention == LDLM_PROCESS_ENQUEUE ?
+                                       NULL : work_list);
+       ENTRY;
+
+       CDEBUG(D_DLMTRACE, "flags %#llx owner %llu pid %u mode %u start "
+              "%llu end %llu\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;
+
+       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 {
-                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)
-                                        ownlocks = tmp;
-                                continue;
-                        }
-
-                        /* 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, mode, *flags);
-                                *err = -EAGAIN;
-                                RETURN(LDLM_ITER_STOP);
-                        }
-
-                        if (*flags & LDLM_FL_TEST_LOCK) {
-                                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 (ldlm_flock_deadlock(req, lock)) {
-                                ldlm_flock_destroy(req, mode, *flags);
-                                *err = -EDEADLK;
-                                RETURN(LDLM_ITER_STOP);
-                        }
-
-
-                        ldlm_flock_blocking_link(req, lock);
-                        ldlm_resource_add_lock(res, &res->lr_waiting, req);
-                        *flags |= LDLM_FL_BLOCK_GRANTED;
-                        RETURN(LDLM_ITER_STOP);
-                }
-        }
-
-        if (*flags & LDLM_FL_TEST_LOCK) {
-                ldlm_flock_destroy(req, mode, *flags);
-                req->l_req_mode = LCK_NL;
-                *flags |= LDLM_FL_LOCK_CHANGED;
-                RETURN(LDLM_ITER_STOP);
-        }
-
-        /* In case we had slept on this lock request take it off of the
-         * deadlock detection waitq. */
-        ldlm_flock_blocking_unlink(req);
-
-        /* 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;
-
-        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 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 (new->l_policy_data.l_flock.start >
-                    lock->l_policy_data.l_flock.end)
-                        continue;
-
-                if (new->l_policy_data.l_flock.end <
-                    lock->l_policy_data.l_flock.start)
-                        break;
-
-                ++overlaps;
-
-                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;
-                        }
-                        ldlm_flock_destroy(lock, lock->l_req_mode, *flags);
-                        continue;
-                }
-                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;
-                }
-
-                /* split the existing lock into two locks */
-
-                /* if this is an F_UNLCK operation then we could avoid
-                 * 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 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) {
-                        unlock_res_and_lock(req);
-                         new2 = ldlm_lock_create(ns, &res->lr_name, LDLM_FLOCK,
-                                        lock->l_granted_mode, &null_cbs,
-                                        NULL, 0);
-                        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_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 */
-                ldlm_resource_add_lock(res, ownlocks, new2);
-                LDLM_LOCK_RELEASE(new2);
-                break;
-        }
-
-        /* 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;
-
-        /* 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);
-        }
-
-        if (*flags != LDLM_FL_WAIT_NOREPROC) {
+       if ((*flags == LDLM_FL_WAIT_NOREPROC) || (mode == LCK_NL)) {
+               /* This loop determines where this processes locks start
+                * in the resource lr_granted list.
+                */
+               list_for_each(tmp, &res->lr_granted) {
+                       lock = list_entry(tmp, struct ldlm_lock,
+                                         l_res_link);
+                       if (ldlm_same_flock_owner(lock, req)) {
+                               ownlocks = tmp;
+                               break;
+                       }
+               }
+       } else {
+               int reprocess_failed = 0;
+               lockmode_verify(mode);
+
+               /* This loop determines if there are existing locks
+                * that conflict with the new lock request.
+                */
+               list_for_each(tmp, &res->lr_granted) {
+                       lock = list_entry(tmp, struct ldlm_lock,
+                                         l_res_link);
+
+                       if (ldlm_same_flock_owner(lock, req)) {
+                               if (!ownlocks)
+                                       ownlocks = tmp;
+                               continue;
+                       }
+
+                       /* locks are compatible, overlap doesn't matter */
+                       if (lockmode_compat(lock->l_granted_mode, mode))
+                               continue;
+
+                       if (!ldlm_flocks_overlap(lock, req))
+                               continue;
+
+                       if (intention != LDLM_PROCESS_ENQUEUE) {
+                               reprocess_failed = 1;
+                               if (ldlm_flock_deadlock(req, lock)) {
+                                       ldlm_flock_cancel_on_deadlock(
+                                               req, grant_work);
+                                       RETURN(LDLM_ITER_CONTINUE);
+                               }
+                               continue;
+                       }
+
+                       if (*flags & LDLM_FL_BLOCK_NOWAIT) {
+                               ldlm_flock_destroy(req, mode, *flags);
+                               *err = -EAGAIN;
+                               RETURN(LDLM_ITER_STOP);
+                       }
+
+                       if (*flags & LDLM_FL_TEST_LOCK) {
+                               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);
+                       }
+
+                       /* add lock to blocking list before deadlock
+                        * check to prevent race
+                        */
+                       ldlm_flock_blocking_link(req, lock);
+
+                       if (ldlm_flock_deadlock(req, lock)) {
+                               ldlm_flock_blocking_unlink(req);
+                               ldlm_flock_destroy(req, mode, *flags);
+                               *err = -EDEADLK;
+                               RETURN(LDLM_ITER_STOP);
+                       }
+
+                       ldlm_resource_add_lock(res, &res->lr_waiting, req);
+                       *flags |= LDLM_FL_BLOCK_GRANTED;
+                       RETURN(LDLM_ITER_STOP);
+               }
+               if (reprocess_failed)
+                       RETURN(LDLM_ITER_CONTINUE);
+       }
+
+       if (*flags & LDLM_FL_TEST_LOCK) {
+               ldlm_flock_destroy(req, mode, *flags);
+               req->l_req_mode = LCK_NL;
+               *flags |= LDLM_FL_LOCK_CHANGED;
+               RETURN(LDLM_ITER_STOP);
+       }
+
+       /* In case we had slept on this lock request take it off of the
+        * deadlock detection hash list.
+        */
+       ldlm_flock_blocking_unlink(req);
+
+       /* 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;
+
+       list_for_remaining_safe(ownlocks, tmp, &res->lr_granted) {
+               lock = list_entry(ownlocks, struct ldlm_lock, l_res_link);
+
+               if (!ldlm_same_flock_owner(lock, new))
+                       break;
+
+               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 (new->l_policy_data.l_flock.start >
+                   lock->l_policy_data.l_flock.end)
+                       continue;
+
+               if (new->l_policy_data.l_flock.end <
+                   lock->l_policy_data.l_flock.start)
+                       break;
+
+               ++overlaps;
+
+               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;
+                       }
+                       ldlm_flock_destroy(lock, lock->l_req_mode, *flags);
+                       continue;
+               }
+               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;
+               }
+
+               /* split the existing lock into two locks */
+
+               /* if this is an F_UNLCK operation then we could avoid
+                * 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 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 == NULL) {
+                       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 (IS_ERR(new2)) {
+                               ldlm_flock_destroy(req, lock->l_granted_mode,
+                                                  *flags);
+                               *err = PTR_ERR(new2);
+                               RETURN(LDLM_ITER_STOP);
+                       }
+                       goto reprocess;
+               }
+
+               splitted = 1;
+
+               new2->l_granted_mode = 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 &&
+                           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 */
+               ldlm_resource_add_lock(res, ownlocks, new2);
+               LDLM_LOCK_RELEASE(new2);
+               break;
+       }
+
+       /* 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;
+
+       /* Add req to the granted queue before calling ldlm_reprocess_all(). */
+       if (!added) {
+               list_del_init(&req->l_res_link);
+               /* insert new lock before ownlocks in list. */
+               ldlm_resource_add_lock(res, ownlocks, req);
+       }
+
+       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;
+               if (intention == LDLM_PROCESS_ENQUEUE) {
+                       /* 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 'intention' won't be
+                        * LDLM_PROCESS_ENQUEUE from ldlm_reprocess_queue.
+                        */
+                       if ((mode == LCK_NL) && overlaps) {
+                               struct list_head rpc_list;
+                               int rc;
+
+                               INIT_LIST_HEAD(&rpc_list);
 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);
-                }
+                               ldlm_reprocess_queue(res, &res->lr_waiting,
+                                                    &rpc_list,
+                                                    LDLM_PROCESS_RESCAN, NULL);
+
+                               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, rc);
+                       }
+               } else {
+                       LASSERT(req->l_completion_ast);
+                       ldlm_add_ast_work_item(req, NULL, grant_work);
+               }
 #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();
+               /* 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 */
-        }
-
-        /* In case we're reprocessing the requested lock we can't destroy
-         * it until after calling ldlm_ast_work_item() above so that lawi()
-         * can bump the reference count on req. Otherwise req could be freed
-         * before the completion AST can be sent.  */
-        if (added)
-                ldlm_flock_destroy(req, mode, *flags);
-
-        ldlm_resource_dump(D_INFO, res);
-        RETURN(LDLM_ITER_CONTINUE);
-}
-
-struct ldlm_flock_wait_data {
-        struct ldlm_lock *fwd_lock;
-        int               fwd_generation;
-};
-
-static void
-ldlm_flock_interrupted_wait(void *data)
-{
-        struct ldlm_lock *lock;
-        ENTRY;
-
-        lock = ((struct ldlm_flock_wait_data *)data)->fwd_lock;
-
-        /* take lock off the deadlock detection waitq. */
-        ldlm_flock_blocking_unlink(lock);
-
-        /* client side - set flag to prevent lock from being put on lru list */
-        lock_res_and_lock(lock);
-        lock->l_flags |= LDLM_FL_CBPENDING;
-        unlock_res_and_lock(lock);
-
-        EXIT;
+       }
+
+       /* 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);
+
+       ldlm_resource_dump(D_INFO, res);
+       RETURN(LDLM_ITER_CONTINUE);
 }
 
 /**
- * Flock completion calback function.
+ * Flock completion callback function.
  *
  * \param lock [in,out]: A lock to be handled
  * \param flags    [in]: flags
@@ -551,179 +640,305 @@ ldlm_flock_interrupted_wait(void *data)
  * \retval <0   : failure
  */
 int
-ldlm_flock_completion_ast(struct ldlm_lock *lock, int flags, void *data)
+ldlm_flock_completion_ast(struct ldlm_lock *lock, __u64 flags, void *data)
 {
-        cfs_flock_t                    *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;
-
-        CDEBUG(D_DLMTRACE, "flags: 0x%x 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))) {
-                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");
-        fwd.fwd_lock = lock;
-        obd = class_exp2obd(lock->l_conn_export);
-
-        /* if this is a local lock, there is no import */
-        if (NULL != obd)
-                imp = obd->u.cli.cl_import;
-
-        if (NULL != imp) {
-                cfs_spin_lock(&imp->imp_lock);
-                fwd.fwd_generation = imp->imp_generation;
-                cfs_spin_unlock(&imp->imp_lock);
-        }
-
-        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, is_granted_or_cancelled(lock), &lwi);
-
-        if (rc) {
-                LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
-                           rc);
-                RETURN(rc);
-        }
+       struct file_lock *getlk = lock->l_ast_data;
+       struct obd_device *obd;
+       struct obd_import *imp = NULL;
+       enum ldlm_error err;
+       int rc = 0;
+       ENTRY;
+
+       OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT2, 4);
+       if (OBD_FAIL_PRECHECK(OBD_FAIL_LDLM_CP_CB_WAIT3)) {
+               lock_res_and_lock(lock);
+               lock->l_flags |= LDLM_FL_FAIL_LOC;
+               unlock_res_and_lock(lock);
+               OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT3, 4);
+       }
+       CDEBUG(D_DLMTRACE, "flags: %#llx data: %p getlk: %p\n",
+              flags, data, getlk);
+
+       LASSERT(flags != LDLM_FL_WAIT_NOREPROC);
+
+       if (flags & LDLM_FL_FAILED)
+               goto granted;
+
+       if (!(flags & LDLM_FL_BLOCKED_MASK)) {
+               if (NULL == data)
+                       /* mds granted the lock in the reply */
+                       goto granted;
+               /* CP AST RPC: lock get granted, wake it up */
+               wake_up(&lock->l_waitq);
+               RETURN(0);
+       }
+
+       LDLM_DEBUG(lock,
+                  "client-side enqueue returned a blocked lock, sleeping");
+       obd = class_exp2obd(lock->l_conn_export);
+
+       /* if this is a local lock, there is no import */
+       if (obd)
+               imp = obd->u.cli.cl_import;
+
+       /* Go to sleep until the lock is granted. */
+       rc = l_wait_event_abortable(lock->l_waitq,
+                                   is_granted_or_cancelled(lock));
+       if (rc < 0) {
+               /* 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
+                */
+               ldlm_set_cbpending(lock);
+               unlock_res_and_lock(lock);
+
+               LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
+                          rc);
+               RETURN(rc);
+       }
 
 granted:
-        OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT, 10);
-
-        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");
-
-        /* take lock off the deadlock detection waitq. */
-        ldlm_flock_blocking_unlink(lock);
-
-        lock_res_and_lock(lock);
-        /* ldlm_lock_enqueue() has already placed lock on the granted list. */
-        cfs_list_del_init(&lock->l_res_link);
-
-        if (flags & LDLM_FL_TEST_LOCK) {
-                /* fcntl(F_GETLK) request */
-                /* 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, cfs_flock_type(getlk),
-                                   LDLM_FL_WAIT_NOREPROC);
-                switch (lock->l_granted_mode) {
-                case LCK_PR:
-                        cfs_flock_set_type(getlk, F_RDLCK);
-                        break;
-                case LCK_PW:
-                        cfs_flock_set_type(getlk, F_WRLCK);
-                        break;
-                default:
-                        cfs_flock_set_type(getlk, F_UNLCK);
-                }
-                cfs_flock_set_pid(getlk,
-                                  (pid_t)lock->l_policy_data.l_flock.pid);
-                cfs_flock_set_start(getlk,
-                                    (loff_t)lock->l_policy_data.l_flock.start);
-                cfs_flock_set_end(getlk,
-                                  (loff_t)lock->l_policy_data.l_flock.end);
-        } else {
-                int 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);
+       OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT, 10);
+
+       if (OBD_FAIL_PRECHECK(OBD_FAIL_LDLM_CP_CB_WAIT4)) {
+               lock_res_and_lock(lock);
+               /* DEADLOCK is always set with CBPENDING */
+               lock->l_flags |= LDLM_FL_FLOCK_DEADLOCK | LDLM_FL_CBPENDING;
+               unlock_res_and_lock(lock);
+               OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT4, 4);
+       }
+       if (OBD_FAIL_PRECHECK(OBD_FAIL_LDLM_CP_CB_WAIT5)) {
+               lock_res_and_lock(lock);
+               /* DEADLOCK is always set with CBPENDING */
+               lock->l_flags |= (LDLM_FL_FAIL_LOC |
+                                 LDLM_FL_FLOCK_DEADLOCK | LDLM_FL_CBPENDING);
+               unlock_res_and_lock(lock);
+               OBD_FAIL_TIMEOUT(OBD_FAIL_LDLM_CP_CB_WAIT5, 4);
+       }
+
+       lock_res_and_lock(lock);
+
+
+       /* Protect against race where lock could have been just destroyed
+        * due to overlap in ldlm_process_flock_lock().
+        */
+       if (ldlm_is_destroyed(lock)) {
+               unlock_res_and_lock(lock);
+               LDLM_DEBUG(lock, "client-side enqueue waking up: destroyed");
+
+               /* An error is still to be returned, to propagate it up to
+                * ldlm_cli_enqueue_fini() caller. */
+               RETURN(-EIO);
+       }
+
+       /* ldlm_lock_enqueue() has already placed lock on the granted list. */
+       ldlm_resource_unlink_lock(lock);
+
+       /* 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.
+        */
+       /* Do the same for DEADLOCK'ed locks. */
+       if (ldlm_is_failed(lock) || ldlm_is_flock_deadlock(lock)) {
+               int mode;
+
+               if (flags & LDLM_FL_TEST_LOCK)
+                       LASSERT(ldlm_is_test_lock(lock));
+
+               if (ldlm_is_test_lock(lock) || ldlm_is_flock_deadlock(lock))
+                       mode = getlk->fl_type;
+               else
+                       mode = lock->l_granted_mode;
+
+               if (ldlm_is_flock_deadlock(lock)) {
+                       LDLM_DEBUG(lock, "client-side enqueue deadlock "
+                                  "received");
+                       rc = -EDEADLK;
+               }
+               ldlm_flock_destroy(lock, mode, LDLM_FL_WAIT_NOREPROC);
+               unlock_res_and_lock(lock);
+
+               /* Need to wake up the waiter if we were evicted */
+               wake_up(&lock->l_waitq);
+
+               /* An error is still to be returned, to propagate it up to
+                * ldlm_cli_enqueue_fini() caller.
+                */
+               RETURN(rc ? : -EIO);
+       }
+
+       LDLM_DEBUG(lock, "client-side enqueue granted");
+
+       if (flags & LDLM_FL_TEST_LOCK) {
+               /*
+                * fcntl(F_GETLK) request
+                * The old mode was saved in getlk->fl_type so that if the mode
+                * in the lock changes we can decref the appropriate refcount.
+                */
+               LASSERT(ldlm_is_test_lock(lock));
+               ldlm_flock_destroy(lock, getlk->fl_type, LDLM_FL_WAIT_NOREPROC);
+               switch (lock->l_granted_mode) {
+               case LCK_PR:
+                       getlk->fl_type = F_RDLCK;
+                       break;
+               case LCK_PW:
+                       getlk->fl_type = F_WRLCK;
+                       break;
+               default:
+                       getlk->fl_type = F_UNLCK;
+               }
+               getlk->fl_pid = (pid_t)lock->l_policy_data.l_flock.pid;
+               getlk->fl_start = (loff_t)lock->l_policy_data.l_flock.start;
+               getlk->fl_end = (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(rc);
 }
 EXPORT_SYMBOL(ldlm_flock_completion_ast);
 
 int ldlm_flock_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
-                            void *data, int flag)
+                           void *data, int flag)
+{
+       ENTRY;
+
+       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_wire_to_local(const union ldlm_wire_policy_data *wpolicy,
+                                    union ldlm_policy_data *lpolicy)
 {
-        ENTRY;
+       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;
+}
 
-        LASSERT(lock);
-        LASSERT(flag == LDLM_CB_CANCELING);
+void ldlm_flock_policy_local_to_wire(const union ldlm_policy_data *lpolicy,
+                                    union ldlm_wire_policy_data *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;
+}
 
-        /* take lock off the deadlock detection waitq. */
-        ldlm_flock_blocking_unlink(lock);
-        RETURN(0);
+/*
+ * Export handle<->flock hash operations.
+ */
+static unsigned
+ldlm_export_flock_hash(struct cfs_hash *hs, const void *key, unsigned mask)
+{
+       return cfs_hash_u64_hash(*(__u64 *)key, mask);
 }
 
-void ldlm_flock_policy_wire18_to_local(const ldlm_wire_policy_data_t *wpolicy,
-                                       ldlm_policy_data_t *lpolicy)
+static void *
+ldlm_export_flock_key(struct hlist_node *hnode)
 {
-        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;
+       struct ldlm_lock *lock;
+
+       lock = 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, struct hlist_node *hnode)
+{
+       return !memcmp(ldlm_export_flock_key(hnode), key, sizeof(__u64));
+}
+
+static void *
+ldlm_export_flock_object(struct hlist_node *hnode)
+{
+       return hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
+}
+
+static void
+ldlm_export_flock_get(struct cfs_hash *hs, struct hlist_node *hnode)
+{
+       struct ldlm_lock *lock;
+       struct ldlm_flock *flock;
+
+       lock = 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);
+       atomic_inc(&flock->blocking_refs);
+}
+
+static void
+ldlm_export_flock_put(struct cfs_hash *hs, struct hlist_node *hnode)
+{
+       struct ldlm_lock *lock;
+       struct ldlm_flock *flock;
+
+       lock = hlist_entry(hnode, struct ldlm_lock, l_exp_flock_hash);
+
+       flock = &lock->l_policy_data.l_flock;
+       LASSERT(flock->blocking_export != NULL);
+       class_export_put(flock->blocking_export);
+       if (atomic_dec_and_test(&flock->blocking_refs)) {
+               flock->blocking_owner = 0;
+               flock->blocking_export = NULL;
+       }
+       LDLM_LOCK_RELEASE(lock);
+}
+
+static struct cfs_hash_ops 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,
+};
 
-void ldlm_flock_policy_wire21_to_local(const ldlm_wire_policy_data_t *wpolicy,
-                                       ldlm_policy_data_t *lpolicy)
+int ldlm_init_flock_export(struct obd_export *exp)
 {
-        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;
+       if( strcmp(exp->exp_obd->obd_type->typ_name, LUSTRE_MDT_NAME) != 0)
+               RETURN(0);
+
+       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);
 }
 
-void ldlm_flock_policy_local_to_wire(const ldlm_policy_data_t *lpolicy,
-                                     ldlm_wire_policy_data_t *wpolicy)
+void ldlm_destroy_flock_export(struct obd_export *exp)
 {
-        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;
+       ENTRY;
+       if (exp->exp_flock_hash) {
+               cfs_hash_putref(exp->exp_flock_hash);
+               exp->exp_flock_hash = NULL;
+       }
+       EXIT;
 }