Whamcloud - gitweb
LU-3540 lod: update recovery thread
[fs/lustre-release.git] / lustre / ldlm / ldlm_lib.c
index a85eea8..2c288c2 100644 (file)
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011, 2012, Whamcloud, Inc.
+ * Copyright (c) 2010, 2014, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
+/**
+ * This file deals with various client/target related logic including recovery.
+ *
+ * TODO: This code more logically belongs in the ptlrpc module than in ldlm and
+ * should be moved.
+ */
+
 #define DEBUG_SUBSYSTEM S_LDLM
 
-#ifdef __KERNEL__
-# include <libcfs/libcfs.h>
-#else
-# include <liblustre.h>
-#endif
+#include <linux/kthread.h>
+#include <libcfs/libcfs.h>
 #include <obd.h>
 #include <obd_class.h>
 #include <lustre_dlm.h>
@@ -48,8 +52,8 @@
 #include <lustre_sec.h>
 #include "ldlm_internal.h"
 
-/* @priority: if non-zero, move the selected to the list head
- * @create: if zero, only search in existed connections
+/* @priority: If non-zero, move the selected connection to the list head.
+ * @create: If zero, only search in existing connections.
  */
 static int import_set_conn(struct obd_import *imp, struct obd_uuid *uuid,
                            int priority, int create)
@@ -77,41 +81,41 @@ static int import_set_conn(struct obd_import *imp, struct obd_uuid *uuid,
                 }
         }
 
-        cfs_spin_lock(&imp->imp_lock);
-        cfs_list_for_each_entry(item, &imp->imp_conn_list, oic_item) {
+       spin_lock(&imp->imp_lock);
+       list_for_each_entry(item, &imp->imp_conn_list, oic_item) {
                 if (obd_uuid_equals(uuid, &item->oic_uuid)) {
                         if (priority) {
-                                cfs_list_del(&item->oic_item);
-                                cfs_list_add(&item->oic_item,
+                               list_del(&item->oic_item);
+                               list_add(&item->oic_item,
                                              &imp->imp_conn_list);
                                 item->oic_last_attempt = 0;
                         }
                         CDEBUG(D_HA, "imp %p@%s: found existing conn %s%s\n",
                                imp, imp->imp_obd->obd_name, uuid->uuid,
                                (priority ? ", moved to head" : ""));
-                        cfs_spin_unlock(&imp->imp_lock);
+                       spin_unlock(&imp->imp_lock);
                         GOTO(out_free, rc = 0);
                 }
         }
-        /* not found */
+       /* No existing import connection found for \a uuid. */
         if (create) {
                 imp_conn->oic_conn = ptlrpc_conn;
                 imp_conn->oic_uuid = *uuid;
                 imp_conn->oic_last_attempt = 0;
                 if (priority)
-                        cfs_list_add(&imp_conn->oic_item, &imp->imp_conn_list);
+                       list_add(&imp_conn->oic_item, &imp->imp_conn_list);
                 else
-                        cfs_list_add_tail(&imp_conn->oic_item,
+                       list_add_tail(&imp_conn->oic_item,
                                           &imp->imp_conn_list);
                 CDEBUG(D_HA, "imp %p@%s: add connection %s at %s\n",
                        imp, imp->imp_obd->obd_name, uuid->uuid,
                        (priority ? "head" : "tail"));
         } else {
-                cfs_spin_unlock(&imp->imp_lock);
-                GOTO(out_free, rc = -ENOENT);
-        }
+               spin_unlock(&imp->imp_lock);
+               GOTO(out_free, rc = -ENOENT);
+       }
 
-        cfs_spin_unlock(&imp->imp_lock);
+       spin_unlock(&imp->imp_lock);
         RETURN(0);
 out_free:
         if (imp_conn)
@@ -131,26 +135,26 @@ int client_import_add_conn(struct obd_import *imp, struct obd_uuid *uuid,
 {
         return import_set_conn(imp, uuid, priority, 1);
 }
+EXPORT_SYMBOL(client_import_add_conn);
 
 int client_import_del_conn(struct obd_import *imp, struct obd_uuid *uuid)
 {
-        struct obd_import_conn *imp_conn;
-        struct obd_export *dlmexp;
-        int rc = -ENOENT;
-        ENTRY;
+       struct obd_import_conn *imp_conn;
+       struct obd_export *dlmexp;
+       int rc = -ENOENT;
+       ENTRY;
 
-        cfs_spin_lock(&imp->imp_lock);
-        if (cfs_list_empty(&imp->imp_conn_list)) {
+       spin_lock(&imp->imp_lock);
+       if (list_empty(&imp->imp_conn_list)) {
                 LASSERT(!imp->imp_connection);
                 GOTO(out, rc);
         }
 
-        cfs_list_for_each_entry(imp_conn, &imp->imp_conn_list, oic_item) {
+       list_for_each_entry(imp_conn, &imp->imp_conn_list, oic_item) {
                 if (!obd_uuid_equals(uuid, &imp_conn->oic_uuid))
                         continue;
                 LASSERT(imp_conn->oic_conn);
 
-                /* is current conn? */
                 if (imp_conn == imp->imp_conn_current) {
                         LASSERT(imp_conn->oic_conn == imp->imp_connection);
 
@@ -172,7 +176,7 @@ int client_import_del_conn(struct obd_import *imp, struct obd_uuid *uuid)
                         }
                 }
 
-                cfs_list_del(&imp_conn->oic_item);
+               list_del(&imp_conn->oic_item);
                 ptlrpc_connection_put(imp_conn->oic_conn);
                 OBD_FREE(imp_conn, sizeof(*imp_conn));
                 CDEBUG(D_HA, "imp %p@%s: remove connection %s\n",
@@ -181,41 +185,42 @@ int client_import_del_conn(struct obd_import *imp, struct obd_uuid *uuid)
                 break;
         }
 out:
-        cfs_spin_unlock(&imp->imp_lock);
-        if (rc == -ENOENT)
-                CERROR("connection %s not found\n", uuid->uuid);
-        RETURN(rc);
+       spin_unlock(&imp->imp_lock);
+       if (rc == -ENOENT)
+               CERROR("connection %s not found\n", uuid->uuid);
+       RETURN(rc);
 }
+EXPORT_SYMBOL(client_import_del_conn);
 
 /**
- * Find conn uuid by peer nid. @peer is a server nid. This function is used
- * to find a conn uuid of @imp which can reach @peer.
+ * Find conn UUID by peer NID. \a peer is a server NID. This function is used
+ * to find a conn uuid of \a imp which can reach \a peer.
  */
 int client_import_find_conn(struct obd_import *imp, lnet_nid_t peer,
-                            struct obd_uuid *uuid)
+                           struct obd_uuid *uuid)
 {
-        struct obd_import_conn *conn;
-        int rc = -ENOENT;
-        ENTRY;
+       struct obd_import_conn *conn;
+       int rc = -ENOENT;
+       ENTRY;
 
-        cfs_spin_lock(&imp->imp_lock);
-        cfs_list_for_each_entry(conn, &imp->imp_conn_list, oic_item) {
-                /* check if conn uuid does have this peer nid */
+       spin_lock(&imp->imp_lock);
+       list_for_each_entry(conn, &imp->imp_conn_list, oic_item) {
+               /* Check if conn UUID does have this peer NID. */
                 if (class_check_uuid(&conn->oic_uuid, peer)) {
                         *uuid = conn->oic_uuid;
                         rc = 0;
                         break;
                 }
         }
-        cfs_spin_unlock(&imp->imp_lock);
-        RETURN(rc);
+       spin_unlock(&imp->imp_lock);
+       RETURN(rc);
 }
 EXPORT_SYMBOL(client_import_find_conn);
 
 void client_destroy_import(struct obd_import *imp)
 {
-        /* drop security policy instance after all rpc finished/aborted
-         * to let all busy contexts be released. */
+       /* Drop security policy instance after all RPCs have finished/aborted
+        * to let all busy contexts be released. */
         class_import_get(imp);
         class_destroy_import(imp);
         sptlrpc_import_sec_put(imp);
@@ -224,7 +229,7 @@ void client_destroy_import(struct obd_import *imp)
 EXPORT_SYMBOL(client_destroy_import);
 
 /**
- * check whether the osc is on MDT or not
+ * Check whether or not the OSC is on MDT.
  * In the config log,
  * osc on MDT
  *     setup 0:{fsname}-OSTxxxx-osc[-MDTxxxx] 1:lustre-OST0000_UUID 2:NID
@@ -246,7 +251,7 @@ static int osc_on_mdt(char *obdname)
        return 0;
 }
 
-/* configure an RPC client OBD device
+/* Configure an RPC client OBD device.
  *
  * lcfg parameters:
  * 1 - client UUID
@@ -266,26 +271,37 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
 
         /* In a more perfect world, we would hang a ptlrpc_client off of
          * obd_type and just use the values from there. */
-       if (!strcmp(name, LUSTRE_OSC_NAME) ||
-           (!strcmp(name, LUSTRE_OSP_NAME) &&
-            !is_osp_on_ost(lustre_cfg_buf(lcfg, 0)))) {
-                rq_portal = OST_REQUEST_PORTAL;
-                rp_portal = OSC_REPLY_PORTAL;
-                connect_op = OST_CONNECT;
-                cli->cl_sp_me = LUSTRE_SP_CLI;
-                cli->cl_sp_to = LUSTRE_SP_OST;
-                ns_type = LDLM_NS_TYPE_OSC;
-
+       if (!strcmp(name, LUSTRE_OSC_NAME)) {
+               rq_portal = OST_REQUEST_PORTAL;
+               rp_portal = OSC_REPLY_PORTAL;
+               connect_op = OST_CONNECT;
+               cli->cl_sp_me = LUSTRE_SP_CLI;
+               cli->cl_sp_to = LUSTRE_SP_OST;
+               ns_type = LDLM_NS_TYPE_OSC;
        } else if (!strcmp(name, LUSTRE_MDC_NAME) ||
-                  (!strcmp(name, LUSTRE_OSP_NAME) &&
-                   is_osp_on_ost(lustre_cfg_buf(lcfg, 0)))) {
-                rq_portal = MDS_REQUEST_PORTAL;
-                rp_portal = MDC_REPLY_PORTAL;
-                connect_op = MDS_CONNECT;
-                cli->cl_sp_me = LUSTRE_SP_CLI;
-                cli->cl_sp_to = LUSTRE_SP_MDT;
-                ns_type = LDLM_NS_TYPE_MDC;
-
+                  !strcmp(name, LUSTRE_LWP_NAME)) {
+               rq_portal = MDS_REQUEST_PORTAL;
+               rp_portal = MDC_REPLY_PORTAL;
+               connect_op = MDS_CONNECT;
+               cli->cl_sp_me = LUSTRE_SP_CLI;
+               cli->cl_sp_to = LUSTRE_SP_MDT;
+               ns_type = LDLM_NS_TYPE_MDC;
+       } else if (!strcmp(name, LUSTRE_OSP_NAME)) {
+               if (strstr(lustre_cfg_buf(lcfg, 1), "OST") == NULL) {
+                       /* OSP_on_MDT for other MDTs */
+                       connect_op = MDS_CONNECT;
+                       cli->cl_sp_to = LUSTRE_SP_MDT;
+                       ns_type = LDLM_NS_TYPE_MDC;
+                       rq_portal = OUT_PORTAL;
+               } else {
+                       /* OSP on MDT for OST */
+                       connect_op = OST_CONNECT;
+                       cli->cl_sp_to = LUSTRE_SP_OST;
+                       ns_type = LDLM_NS_TYPE_OSC;
+                       rq_portal = OST_REQUEST_PORTAL;
+               }
+               rp_portal = OSC_REPLY_PORTAL;
+               cli->cl_sp_me = LUSTRE_SP_CLI;
         } else if (!strcmp(name, LUSTRE_MGC_NAME)) {
                 rq_portal = MGS_REQUEST_PORTAL;
                 rp_portal = MGC_REPLY_PORTAL;
@@ -294,16 +310,7 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
                 cli->cl_sp_to = LUSTRE_SP_MGS;
                 cli->cl_flvr_mgc.sf_rpc = SPTLRPC_FLVR_INVALID;
                 ns_type = LDLM_NS_TYPE_MGC;
-
-       } else if (!strcmp(name, LUSTRE_OSP_NAME)) {
-               rq_portal = OST_REQUEST_PORTAL;
-               rp_portal = OSC_REPLY_PORTAL;
-               connect_op = OST_CONNECT;
-               cli->cl_sp_me = LUSTRE_SP_CLI;
-               cli->cl_sp_to = LUSTRE_SP_OST;
-               ns_type = LDLM_NS_TYPE_OSC;
-
-        } else {
+       } else {
                 CERROR("unknown client OBD type \"%s\", can't setup\n",
                        name);
                 RETURN(-EINVAL);
@@ -329,68 +336,84 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
                 RETURN(-EINVAL);
         }
 
-        cfs_init_rwsem(&cli->cl_sem);
-        cfs_sema_init(&cli->cl_mgc_sem, 1);
+       init_rwsem(&cli->cl_sem);
+       mutex_init(&cli->cl_mgc_mutex);
         cli->cl_conn_count = 0;
         memcpy(server_uuid.uuid, lustre_cfg_buf(lcfg, 2),
                min_t(unsigned int, LUSTRE_CFG_BUFLEN(lcfg, 2),
                      sizeof(server_uuid)));
 
-        cli->cl_dirty = 0;
-        cli->cl_avail_grant = 0;
-        /* FIXME: should limit this for the sum of all cl_dirty_max */
-        cli->cl_dirty_max = OSC_MAX_DIRTY_DEFAULT * 1024 * 1024;
-        if (cli->cl_dirty_max >> CFS_PAGE_SHIFT > cfs_num_physpages / 8)
-                cli->cl_dirty_max = cfs_num_physpages << (CFS_PAGE_SHIFT - 3);
-        CFS_INIT_LIST_HEAD(&cli->cl_cache_waiters);
-        CFS_INIT_LIST_HEAD(&cli->cl_loi_ready_list);
-        CFS_INIT_LIST_HEAD(&cli->cl_loi_hp_ready_list);
-        CFS_INIT_LIST_HEAD(&cli->cl_loi_write_list);
-        CFS_INIT_LIST_HEAD(&cli->cl_loi_read_list);
-        client_obd_list_lock_init(&cli->cl_loi_list_lock);
-       cfs_atomic_set(&cli->cl_pending_w_pages, 0);
-       cfs_atomic_set(&cli->cl_pending_r_pages, 0);
-        cli->cl_r_in_flight = 0;
-        cli->cl_w_in_flight = 0;
-
-        cfs_spin_lock_init(&cli->cl_read_rpc_hist.oh_lock);
-        cfs_spin_lock_init(&cli->cl_write_rpc_hist.oh_lock);
-        cfs_spin_lock_init(&cli->cl_read_page_hist.oh_lock);
-        cfs_spin_lock_init(&cli->cl_write_page_hist.oh_lock);
-        cfs_spin_lock_init(&cli->cl_read_offset_hist.oh_lock);
-        cfs_spin_lock_init(&cli->cl_write_offset_hist.oh_lock);
-        cfs_waitq_init(&cli->cl_destroy_waitq);
-        cfs_atomic_set(&cli->cl_destroy_in_flight, 0);
+       cli->cl_dirty_pages = 0;
+       cli->cl_avail_grant = 0;
+       /* FIXME: Should limit this for the sum of all cl_dirty_max_pages. */
+       /* cl_dirty_max_pages may be changed at connect time in
+        * ptlrpc_connect_interpret(). */
+       client_adjust_max_dirty(cli);
+       INIT_LIST_HEAD(&cli->cl_cache_waiters);
+       INIT_LIST_HEAD(&cli->cl_loi_ready_list);
+       INIT_LIST_HEAD(&cli->cl_loi_hp_ready_list);
+       INIT_LIST_HEAD(&cli->cl_loi_write_list);
+       INIT_LIST_HEAD(&cli->cl_loi_read_list);
+       spin_lock_init(&cli->cl_loi_list_lock);
+       atomic_set(&cli->cl_pending_w_pages, 0);
+       atomic_set(&cli->cl_pending_r_pages, 0);
+       cli->cl_r_in_flight = 0;
+       cli->cl_w_in_flight = 0;
+
+       spin_lock_init(&cli->cl_read_rpc_hist.oh_lock);
+       spin_lock_init(&cli->cl_write_rpc_hist.oh_lock);
+       spin_lock_init(&cli->cl_read_page_hist.oh_lock);
+       spin_lock_init(&cli->cl_write_page_hist.oh_lock);
+       spin_lock_init(&cli->cl_read_offset_hist.oh_lock);
+       spin_lock_init(&cli->cl_write_offset_hist.oh_lock);
+
+       /* lru for osc. */
+       INIT_LIST_HEAD(&cli->cl_lru_osc);
+       atomic_set(&cli->cl_lru_shrinkers, 0);
+       atomic_long_set(&cli->cl_lru_busy, 0);
+       atomic_long_set(&cli->cl_lru_in_list, 0);
+       INIT_LIST_HEAD(&cli->cl_lru_list);
+       spin_lock_init(&cli->cl_lru_list_lock);
+       atomic_long_set(&cli->cl_unstable_count, 0);
+
+       init_waitqueue_head(&cli->cl_destroy_waitq);
+       atomic_set(&cli->cl_destroy_in_flight, 0);
 #ifdef ENABLE_CHECKSUM
-        /* Turn on checksumming by default. */
-        cli->cl_checksum = 1;
-        /*
-         * The supported checksum types will be worked out at connect time
-         * Set cl_chksum* to CRC32 for now to avoid returning screwed info
-         * through procfs.
-         */
-        cli->cl_cksum_type = cli->cl_supp_cksum_types = OBD_CKSUM_CRC32;
+       /* Turn on checksumming by default. */
+       cli->cl_checksum = 1;
+       /*
+        * The supported checksum types will be worked out at connect time
+        * Set cl_chksum* to CRC32 for now to avoid returning screwed info
+        * through procfs.
+        */
+       cli->cl_cksum_type = cli->cl_supp_cksum_types = OBD_CKSUM_CRC32;
 #endif
-        cfs_atomic_set(&cli->cl_resends, OSC_DEFAULT_RESENDS);
-
-        /* This value may be changed at connect time in
-           ptlrpc_connect_interpret. */
-        cli->cl_max_pages_per_rpc = min((int)PTLRPC_MAX_BRW_PAGES,
-                                        (int)(1024 * 1024 >> CFS_PAGE_SHIFT));
-
-        if (!strcmp(name, LUSTRE_MDC_NAME)) {
-                cli->cl_max_rpcs_in_flight = MDC_MAX_RIF_DEFAULT;
-        } else if (cfs_num_physpages >> (20 - CFS_PAGE_SHIFT) <= 128 /* MB */) {
-                cli->cl_max_rpcs_in_flight = 2;
-        } else if (cfs_num_physpages >> (20 - CFS_PAGE_SHIFT) <= 256 /* MB */) {
-                cli->cl_max_rpcs_in_flight = 3;
-        } else if (cfs_num_physpages >> (20 - CFS_PAGE_SHIFT) <= 512 /* MB */) {
-                cli->cl_max_rpcs_in_flight = 4;
-        } else {
+       atomic_set(&cli->cl_resends, OSC_DEFAULT_RESENDS);
+
+       /* This value may be reduced at connect time in
+        * ptlrpc_connect_interpret() . We initialize it to only
+        * 1MB until we know what the performance looks like.
+        * In the future this should likely be increased. LU-1431 */
+       cli->cl_max_pages_per_rpc = min_t(int, PTLRPC_MAX_BRW_PAGES,
+                                         LNET_MTU >> PAGE_CACHE_SHIFT);
+
+       /* set cl_chunkbits default value to PAGE_CACHE_SHIFT,
+        * it will be updated at OSC connection time. */
+       cli->cl_chunkbits = PAGE_CACHE_SHIFT;
+
+       if (!strcmp(name, LUSTRE_MDC_NAME)) {
+               cli->cl_max_rpcs_in_flight = OBD_MAX_RIF_DEFAULT;
+       } else if (totalram_pages >> (20 - PAGE_CACHE_SHIFT) <= 128 /* MB */) {
+               cli->cl_max_rpcs_in_flight = 2;
+       } else if (totalram_pages >> (20 - PAGE_CACHE_SHIFT) <= 256 /* MB */) {
+               cli->cl_max_rpcs_in_flight = 3;
+       } else if (totalram_pages >> (20 - PAGE_CACHE_SHIFT) <= 512 /* MB */) {
+               cli->cl_max_rpcs_in_flight = 4;
+       } else {
                if (osc_on_mdt(obddev->obd_name))
-                       cli->cl_max_rpcs_in_flight = MDS_OSC_MAX_RIF_DEFAULT;
+                       cli->cl_max_rpcs_in_flight = OBD_MAX_RIF_MAX;
                else
-                       cli->cl_max_rpcs_in_flight = OSC_MAX_RIF_DEFAULT;
+                       cli->cl_max_rpcs_in_flight = OBD_MAX_RIF_DEFAULT;
         }
         rc = ldlm_get_ref();
         if (rc) {
@@ -406,7 +429,6 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
                 GOTO(err_ldlm, rc = -ENOENT);
         imp->imp_client = &obddev->obd_ldlm_client;
         imp->imp_connect_op = connect_op;
-        CFS_INIT_LIST_HEAD(&imp->imp_pinger_chain);
         memcpy(cli->cl_target_uuid.uuid, lustre_cfg_buf(lcfg, 1),
                LUSTRE_CFG_BUFLEN(lcfg, 1));
         class_import_put(imp);
@@ -417,19 +439,18 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
                 GOTO(err_import, rc);
         }
 
-        cli->cl_import = imp;
-        /* cli->cl_max_mds_{easize,cookiesize} updated by mdc_init_ea_size() */
-        cli->cl_max_mds_easize = sizeof(struct lov_mds_md_v3);
-        cli->cl_max_mds_cookiesize = sizeof(struct llog_cookie);
+       cli->cl_import = imp;
+       /* cli->cl_max_mds_easize updated by mdc_init_ea_size() */
+       cli->cl_max_mds_easize = sizeof(struct lov_mds_md_v3);
 
         if (LUSTRE_CFG_BUFLEN(lcfg, 3) > 0) {
                 if (!strcmp(lustre_cfg_string(lcfg, 3), "inactive")) {
                         CDEBUG(D_HA, "marking %s %s->%s as inactive\n",
                                name, obddev->obd_name,
                                cli->cl_target_uuid.uuid);
-                        cfs_spin_lock(&imp->imp_lock);
-                        imp->imp_deactive = 1;
-                        cfs_spin_unlock(&imp->imp_lock);
+                       spin_lock(&imp->imp_lock);
+                       imp->imp_deactive = 1;
+                       spin_unlock(&imp->imp_lock);
                 }
         }
 
@@ -443,8 +464,6 @@ int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
                 GOTO(err_import, rc = -ENOMEM);
         }
 
-        cli->cl_qchk_stat = CL_NOT_QUOTACHECKED;
-
         RETURN(rc);
 
 err_import:
@@ -455,19 +474,22 @@ err:
         RETURN(rc);
 
 }
+EXPORT_SYMBOL(client_obd_setup);
 
 int client_obd_cleanup(struct obd_device *obddev)
 {
-        ENTRY;
+       ENTRY;
 
-        ldlm_namespace_free_post(obddev->obd_namespace);
-        obddev->obd_namespace = NULL;
+       ldlm_namespace_free_post(obddev->obd_namespace);
+       obddev->obd_namespace = NULL;
 
-        LASSERT(obddev->u.cli.cl_import == NULL);
+       obd_cleanup_client_import(obddev);
+       LASSERT(obddev->u.cli.cl_import == NULL);
 
-        ldlm_put_ref();
-        RETURN(0);
+       ldlm_put_ref();
+       RETURN(0);
 }
+EXPORT_SYMBOL(client_obd_cleanup);
 
 /* ->o_connect() method for client side (OSC and MDC and MGC) */
 int client_connect_import(const struct lu_env *env,
@@ -475,16 +497,16 @@ int client_connect_import(const struct lu_env *env,
                           struct obd_device *obd, struct obd_uuid *cluuid,
                           struct obd_connect_data *data, void *localdata)
 {
-        struct client_obd *cli = &obd->u.cli;
-        struct obd_import *imp = cli->cl_import;
-        struct obd_connect_data *ocd;
-        struct lustre_handle conn = { 0 };
-        int rc;
-        ENTRY;
+       struct client_obd       *cli    = &obd->u.cli;
+       struct obd_import       *imp    = cli->cl_import;
+       struct obd_connect_data *ocd;
+       struct lustre_handle    conn    = { 0 };
+       int                     rc;
+       ENTRY;
 
         *exp = NULL;
-        cfs_down_write(&cli->cl_sem);
-        if (cli->cl_conn_count > 0 )
+       down_write(&cli->cl_sem);
+       if (cli->cl_conn_count > 0)
                 GOTO(out_sem, rc = -EALREADY);
 
         rc = class_connect(&conn, obd, cluuid);
@@ -512,7 +534,7 @@ int client_connect_import(const struct lu_env *env,
                 LASSERT (imp->imp_state == LUSTRE_IMP_DISCON);
                 GOTO(out_ldlm, rc);
         }
-        LASSERT((*exp)->exp_connection);
+       LASSERT(*exp != NULL && (*exp)->exp_connection);
 
         if (data) {
                 LASSERTF((ocd->ocd_connect_flags & data->ocd_connect_flags) ==
@@ -532,10 +554,11 @@ out_ldlm:
                 *exp = NULL;
         }
 out_sem:
-        cfs_up_write(&cli->cl_sem);
+       up_write(&cli->cl_sem);
 
-        return rc;
+       return rc;
 }
+EXPORT_SYMBOL(client_connect_import);
 
 int client_disconnect_export(struct obd_export *exp)
 {
@@ -554,26 +577,26 @@ int client_disconnect_export(struct obd_export *exp)
         cli = &obd->u.cli;
         imp = cli->cl_import;
 
-        cfs_down_write(&cli->cl_sem);
-        CDEBUG(D_INFO, "disconnect %s - %d\n", obd->obd_name,
-               cli->cl_conn_count);
+       down_write(&cli->cl_sem);
+       CDEBUG(D_INFO, "disconnect %s - %zu\n", obd->obd_name,
+               cli->cl_conn_count);
 
-        if (!cli->cl_conn_count) {
+       if (cli->cl_conn_count == 0) {
                 CERROR("disconnecting disconnected device (%s)\n",
                        obd->obd_name);
                 GOTO(out_disconnect, rc = -EINVAL);
         }
 
         cli->cl_conn_count--;
-        if (cli->cl_conn_count)
+       if (cli->cl_conn_count != 0)
                 GOTO(out_disconnect, rc = 0);
 
-        /* Mark import deactivated now, so we don't try to reconnect if any
-         * of the cleanup RPCs fails (e.g. ldlm cancel, etc).  We don't
-         * fully deactivate the import, or that would drop all requests. */
-        cfs_spin_lock(&imp->imp_lock);
-        imp->imp_deactive = 1;
-        cfs_spin_unlock(&imp->imp_lock);
+       /* Mark import deactivated now, so we don't try to reconnect if any
+        * of the cleanup RPCs fails (e.g. LDLM cancel, etc).  We don't
+        * fully deactivate the import, or that would drop all requests. */
+       spin_lock(&imp->imp_lock);
+       imp->imp_deactive = 1;
+       spin_unlock(&imp->imp_lock);
 
         /* Some non-replayable imports (MDS's OSCs) are pinged, so just
          * delete it regardless.  (It's safe to delete an import that was
@@ -587,29 +610,28 @@ int client_disconnect_export(struct obd_export *exp)
                 ldlm_namespace_free_prior(obd->obd_namespace, imp, obd->obd_force);
         }
 
-        /*
-         * there's no need to hold sem during disconnecting an import,
-         * and actually it may cause deadlock in gss.
-         */
-        cfs_up_write(&cli->cl_sem);
-        rc = ptlrpc_disconnect_import(imp, 0);
-        cfs_down_write(&cli->cl_sem);
+       /* There's no need to hold sem while disconnecting an import,
+        * and it may actually cause deadlock in GSS. */
+       up_write(&cli->cl_sem);
+       rc = ptlrpc_disconnect_import(imp, 0);
+       down_write(&cli->cl_sem);
 
         ptlrpc_invalidate_import(imp);
 
         EXIT;
 
- out_disconnect:
-        /* use server style - class_disconnect should be always called for
-         * o_disconnect */
+out_disconnect:
+       /* Use server style - class_disconnect should be always called for
+        * o_disconnect. */
         err = class_disconnect(exp);
         if (!rc && err)
                 rc = err;
 
-        cfs_up_write(&cli->cl_sem);
+       up_write(&cli->cl_sem);
 
         RETURN(rc);
 }
+EXPORT_SYMBOL(client_disconnect_export);
 
 #ifdef HAVE_SERVER_SUPPORT
 int server_disconnect_export(struct obd_export *exp)
@@ -617,36 +639,37 @@ int server_disconnect_export(struct obd_export *exp)
         int rc;
         ENTRY;
 
-        /* Disconnect early so that clients can't keep using export */
-        rc = class_disconnect(exp);
-        /* close import for avoid sending any requests */
-        if (exp->exp_imp_reverse)
-                ptlrpc_cleanup_imp(exp->exp_imp_reverse);
+       /* Disconnect early so that clients can't keep using export. */
+       rc = class_disconnect(exp);
+       /* Close import to avoid sending any requests. */
+       if (exp->exp_imp_reverse)
+               ptlrpc_cleanup_imp(exp->exp_imp_reverse);
 
-        if (exp->exp_obd->obd_namespace != NULL)
-                ldlm_cancel_locks_for_export(exp);
+       if (exp->exp_obd->obd_namespace != NULL)
+               ldlm_cancel_locks_for_export(exp);
 
         /* complete all outstanding replies */
-        cfs_spin_lock(&exp->exp_lock);
-        while (!cfs_list_empty(&exp->exp_outstanding_replies)) {
-                struct ptlrpc_reply_state *rs =
-                        cfs_list_entry(exp->exp_outstanding_replies.next,
-                                       struct ptlrpc_reply_state, rs_exp_list);
+       spin_lock(&exp->exp_lock);
+       while (!list_empty(&exp->exp_outstanding_replies)) {
+               struct ptlrpc_reply_state *rs =
+                       list_entry(exp->exp_outstanding_replies.next,
+                                      struct ptlrpc_reply_state, rs_exp_list);
                struct ptlrpc_service_part *svcpt = rs->rs_svcpt;
 
-               cfs_spin_lock(&svcpt->scp_rep_lock);
+               spin_lock(&svcpt->scp_rep_lock);
 
-               cfs_list_del_init(&rs->rs_exp_list);
-               cfs_spin_lock(&rs->rs_lock);
+               list_del_init(&rs->rs_exp_list);
+               spin_lock(&rs->rs_lock);
                ptlrpc_schedule_difficult_reply(rs);
-               cfs_spin_unlock(&rs->rs_lock);
+               spin_unlock(&rs->rs_lock);
 
-               cfs_spin_unlock(&svcpt->scp_rep_lock);
+               spin_unlock(&svcpt->scp_rep_lock);
        }
-       cfs_spin_unlock(&exp->exp_lock);
+       spin_unlock(&exp->exp_lock);
 
        RETURN(rc);
 }
+EXPORT_SYMBOL(server_disconnect_export);
 
 /* --------------------------------------------------------------------------
  * from old lib/target.c
@@ -722,24 +745,15 @@ void target_client_add_cb(struct obd_device *obd, __u64 transno, void *cb_data,
         CDEBUG(D_RPCTRACE, "%s: committing for initial connect of %s\n",
                obd->obd_name, exp->exp_client_uuid.uuid);
 
-        cfs_spin_lock(&exp->exp_lock);
-        exp->exp_need_sync = 0;
-        cfs_spin_unlock(&exp->exp_lock);
-        class_export_cb_put(exp);
+       spin_lock(&exp->exp_lock);
+       exp->exp_need_sync = 0;
+       spin_unlock(&exp->exp_lock);
+       class_export_cb_put(exp);
 }
-EXPORT_SYMBOL(target_client_add_cb);
 
-#ifdef __KERNEL__
 static void
 check_and_start_recovery_timer(struct obd_device *obd,
                                struct ptlrpc_request *req, int new_client);
-#else
-static inline void
-check_and_start_recovery_timer(struct obd_device *obd,
-                               struct ptlrpc_request *req, int new_client)
-{
-}
-#endif
 
 int target_handle_connect(struct ptlrpc_request *req)
 {
@@ -757,6 +771,8 @@ int target_handle_connect(struct ptlrpc_request *req)
         char *target_start;
         int target_len;
        bool     mds_conn = false, lw_client = false;
+       bool     mds_mds_conn = false;
+       bool     new_mds_mds_conn = false;
         struct obd_connect_data *data, *tmpdata;
         int size, tmpsize;
         lnet_nid_t *client_nid = NULL;
@@ -777,40 +793,43 @@ int target_handle_connect(struct ptlrpc_request *req)
 
        if (!target) {
                deuuidify(str, NULL, &target_start, &target_len);
-               LCONSOLE_ERROR_MSG(0x137, "UUID '%s' is not available for "
-                                  "connect (no target)\n", str);
+               LCONSOLE_ERROR_MSG(0x137, "%s: not available for connect "
+                                  "from %s (no target). If you are running "
+                                  "an HA pair check that the target is "
+                                  "mounted on the other server.\n", str,
+                                  libcfs_nid2str(req->rq_peer.nid));
                GOTO(out, rc = -ENODEV);
        }
 
-       cfs_spin_lock(&target->obd_dev_lock);
+       spin_lock(&target->obd_dev_lock);
        if (target->obd_stopping || !target->obd_set_up) {
-               cfs_spin_unlock(&target->obd_dev_lock);
+               spin_unlock(&target->obd_dev_lock);
 
                deuuidify(str, NULL, &target_start, &target_len);
-               LCONSOLE_ERROR_MSG(0x137, "%.*s: Not available for connect "
-                                  "from %s (%s)\n", target_len, target_start,
-                                  libcfs_nid2str(req->rq_peer.nid), 
-                                  (target->obd_stopping ?
-                                  "stopping" : "not set up"));
+               LCONSOLE_INFO("%.*s: Not available for connect from %s (%s)\n",
+                             target_len, target_start,
+                             libcfs_nid2str(req->rq_peer.nid),
+                             (target->obd_stopping ?
+                              "stopping" : "not set up"));
                GOTO(out, rc = -ENODEV);
        }
 
         if (target->obd_no_conn) {
-               cfs_spin_unlock(&target->obd_dev_lock);
+               spin_unlock(&target->obd_dev_lock);
 
-                LCONSOLE_WARN("%s: Temporarily refusing client connection "
-                              "from %s\n", target->obd_name,
-                              libcfs_nid2str(req->rq_peer.nid));
-                GOTO(out, rc = -EAGAIN);
-        }
+               CDEBUG(D_INFO, "%s: Temporarily refusing client connection "
+                              "from %s\n", target->obd_name,
+                              libcfs_nid2str(req->rq_peer.nid));
+               GOTO(out, rc = -EAGAIN);
+       }
 
-        /* Make sure the target isn't cleaned up while we're here. Yes,
-           there's still a race between the above check and our incref here.
-           Really, class_uuid2obd should take the ref. */
-        targref = class_incref(target, __FUNCTION__, cfs_current());
+       /* Make sure the target isn't cleaned up while we're here. Yes,
+        * there's still a race between the above check and our incref here.
+        * Really, class_uuid2obd should take the ref. */
+       targref = class_incref(target, __FUNCTION__, current);
 
        target->obd_conn_inprogress++;
-       cfs_spin_unlock(&target->obd_dev_lock);
+       spin_unlock(&target->obd_dev_lock);
 
         str = req_capsule_client_get(&req->rq_pill, &RMF_CLUUID);
         if (str == NULL) {
@@ -820,9 +839,9 @@ int target_handle_connect(struct ptlrpc_request *req)
 
         obd_str2uuid(&cluuid, str);
 
-        /* XXX extract a nettype and format accordingly */
-        switch (sizeof(lnet_nid_t)) {
-                /* NB the casts only avoid compiler warnings */
+       /* XXX Extract a nettype and format accordingly. */
+       switch (sizeof(lnet_nid_t)) {
+       /* NB the casts only avoid compiler warnings. */
         case 8:
                 snprintf(remote_uuid.uuid, sizeof remote_uuid,
                          "NET_"LPX64"_UUID", (__u64)req->rq_peer.nid);
@@ -851,41 +870,87 @@ int target_handle_connect(struct ptlrpc_request *req)
         if (rc)
                 GOTO(out, rc);
 
-        if (lustre_msg_get_op_flags(req->rq_reqmsg) & MSG_CONNECT_LIBCLIENT) {
-                if (!data) {
-                        DEBUG_REQ(D_WARNING, req, "Refusing old (unversioned) "
-                                  "libclient connection attempt");
-                        GOTO(out, rc = -EPROTO);
-                } else if (data->ocd_version < LUSTRE_VERSION_CODE -
-                                               LUSTRE_VERSION_ALLOWED_OFFSET ||
-                           data->ocd_version > LUSTRE_VERSION_CODE +
-                                               LUSTRE_VERSION_ALLOWED_OFFSET) {
-                        DEBUG_REQ(D_WARNING, req, "Refusing %s (%d.%d.%d.%d) "
-                                  "libclient connection attempt",
-                                  data->ocd_version < LUSTRE_VERSION_CODE ?
-                                  "old" : "new",
-                                  OBD_OCD_VERSION_MAJOR(data->ocd_version),
-                                  OBD_OCD_VERSION_MINOR(data->ocd_version),
-                                  OBD_OCD_VERSION_PATCH(data->ocd_version),
-                                  OBD_OCD_VERSION_FIX(data->ocd_version));
-                        data = req_capsule_server_sized_get(&req->rq_pill,
-                                                        &RMF_CONNECT_DATA,
-                                    offsetof(typeof(*data), ocd_version) +
-                                             sizeof(data->ocd_version));
-                        if (data) {
-                                data->ocd_connect_flags = OBD_CONNECT_VERSION;
-                                data->ocd_version = LUSTRE_VERSION_CODE;
-                        }
-                        GOTO(out, rc = -EPROTO);
-                }
-        }
+#if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(3, 0, 53, 0)
+       /* Don't allow clients to connect that are using old 1.8 format
+        * protocol conventions (LUSTRE_MSG_MAGIC_v1, !MSGHDR_CKSUM_INCOMPAT18,
+        * ldlm_flock_policy_wire format, MDT_ATTR_xTIME_SET, etc).  The
+        * FULL20 flag should be set on all connections since 2.0, but no
+        * longer affects behaviour.
+        *
+        * Later this check will be disabled and the flag can be retired
+        * completely once interop with 3.0 is no longer needed.
+        */
+       if (!(data->ocd_connect_flags & OBD_CONNECT_FULL20))
+               GOTO(out, rc = -EPROTO);
+#endif
 
-        if ((lustre_msg_get_op_flags(req->rq_reqmsg) & MSG_CONNECT_INITIAL) &&
-            (data->ocd_connect_flags & OBD_CONNECT_MDS))
-               mds_conn = true;
+       if (lustre_msg_get_op_flags(req->rq_reqmsg) & MSG_CONNECT_LIBCLIENT) {
+               if (data->ocd_version < LUSTRE_VERSION_CODE -
+                                              LUSTRE_VERSION_ALLOWED_OFFSET ||
+                   data->ocd_version > LUSTRE_VERSION_CODE +
+                                              LUSTRE_VERSION_ALLOWED_OFFSET) {
+                       DEBUG_REQ(D_WARNING, req, "Refusing %s (%d.%d.%d.%d) "
+                                 "libclient connection attempt",
+                                 data->ocd_version < LUSTRE_VERSION_CODE ?
+                                 "old" : "new",
+                                 OBD_OCD_VERSION_MAJOR(data->ocd_version),
+                                 OBD_OCD_VERSION_MINOR(data->ocd_version),
+                                 OBD_OCD_VERSION_PATCH(data->ocd_version),
+                                 OBD_OCD_VERSION_FIX(data->ocd_version));
+                       data = req_capsule_server_sized_get(&req->rq_pill,
+                                                           &RMF_CONNECT_DATA,
+                                   offsetof(typeof(*data), ocd_version) +
+                                            sizeof(data->ocd_version));
+                       if (data) {
+                               data->ocd_connect_flags = OBD_CONNECT_VERSION;
+                               data->ocd_version = LUSTRE_VERSION_CODE;
+                       }
+                       GOTO(out, rc = -EPROTO);
+               }
+       }
 
-       if ((data->ocd_connect_flags & OBD_CONNECT_LIGHTWEIGHT) != 0)
-               lw_client = true;
+       /* Note: lw_client is needed in MDS-MDS failover during update log
+        * processing, so we needs to allow lw_client to be connected at
+        * anytime, instead of only the initial connection */
+       lw_client = (data->ocd_connect_flags & OBD_CONNECT_LIGHTWEIGHT) != 0;
+
+       if (lustre_msg_get_op_flags(req->rq_reqmsg) & MSG_CONNECT_INITIAL) {
+               mds_conn = (data->ocd_connect_flags & OBD_CONNECT_MDS) != 0;
+               mds_mds_conn = (data->ocd_connect_flags &
+                               OBD_CONNECT_MDS_MDS) != 0;
+
+               /* OBD_CONNECT_MNE_SWAB is defined as OBD_CONNECT_MDS_MDS
+                * for Imperative Recovery connection from MGC to MGS.
+                *
+                * Via check OBD_CONNECT_FID, we can distinguish whether
+                * the OBD_CONNECT_MDS_MDS/OBD_CONNECT_MNE_SWAB is from
+                * MGC or MDT. */
+               if (!lw_client &&
+                   (data->ocd_connect_flags & OBD_CONNECT_MDS_MDS) &&
+                   (data->ocd_connect_flags & OBD_CONNECT_FID) &&
+                   (data->ocd_connect_flags & OBD_CONNECT_VERSION)) {
+                       __u32 major = OBD_OCD_VERSION_MAJOR(data->ocd_version);
+                       __u32 minor = OBD_OCD_VERSION_MINOR(data->ocd_version);
+                       __u32 patch = OBD_OCD_VERSION_PATCH(data->ocd_version);
+
+                       /* We do not support the MDT-MDT interoperations with
+                        * different version MDT because of protocol changes. */
+                       if (unlikely(major != LUSTRE_MAJOR ||
+                                    minor != LUSTRE_MINOR ||
+                                    abs(patch - LUSTRE_PATCH) > 3)) {
+                               LCONSOLE_WARN("%s (%u.%u.%u.%u) refused the "
+                                       "connection from different version MDT "
+                                       "(%d.%d.%d.%d) %s %s\n",
+                                       target->obd_name, LUSTRE_MAJOR,
+                                       LUSTRE_MINOR, LUSTRE_PATCH, LUSTRE_FIX,
+                                       major, minor, patch,
+                                       OBD_OCD_VERSION_FIX(data->ocd_version),
+                                       libcfs_nid2str(req->rq_peer.nid), str);
+
+                               GOTO(out, rc = -EPROTO);
+                       }
+               }
+       }
 
         /* lctl gets a backstage, all-access pass. */
         if (obd_uuid_equals(&cluuid, &target->obd_uuid))
@@ -895,31 +960,33 @@ int target_handle_connect(struct ptlrpc_request *req)
         if (!export)
                 goto no_export;
 
-        /* we've found an export in the hash */
-
-       cfs_spin_lock(&export->exp_lock);
-
-        if (export->exp_connecting) { /* bug 9635, et. al. */
-               cfs_spin_unlock(&export->exp_lock);
-                LCONSOLE_WARN("%s: Export %p already connecting from %s\n",
-                              export->exp_obd->obd_name, export,
-                              libcfs_nid2str(req->rq_peer.nid));
-                class_export_put(export);
-                export = NULL;
-                rc = -EALREADY;
-        } else if (mds_conn && export->exp_connection) {
-               cfs_spin_unlock(&export->exp_lock);
-                if (req->rq_peer.nid != export->exp_connection->c_peer.nid)
-                        /* mds reconnected after failover */
-                        LCONSOLE_WARN("%s: Received MDS connection from "
-                            "%s, removing former export from %s\n",
-                            target->obd_name, libcfs_nid2str(req->rq_peer.nid),
-                            libcfs_nid2str(export->exp_connection->c_peer.nid));
-                else
-                        /* new mds connection from the same nid */
-                        LCONSOLE_WARN("%s: Received new MDS connection from "
-                            "%s, removing former export from same NID\n",
-                            target->obd_name, libcfs_nid2str(req->rq_peer.nid));
+       /* We've found an export in the hash. */
+
+       spin_lock(&export->exp_lock);
+
+       if (export->exp_connecting) { /* bug 9635, et. al. */
+               spin_unlock(&export->exp_lock);
+               LCONSOLE_WARN("%s: Export %p already connecting from %s\n",
+                             export->exp_obd->obd_name, export,
+                             libcfs_nid2str(req->rq_peer.nid));
+               class_export_put(export);
+               export = NULL;
+               rc = -EALREADY;
+       } else if ((mds_conn || lw_client) && export->exp_connection != NULL) {
+               spin_unlock(&export->exp_lock);
+               if (req->rq_peer.nid != export->exp_connection->c_peer.nid)
+                       /* MDS or LWP reconnected after failover. */
+                       LCONSOLE_WARN("%s: Received %s connection from "
+                           "%s, removing former export from %s\n",
+                           target->obd_name, mds_conn ? "MDS" : "LWP",
+                           libcfs_nid2str(req->rq_peer.nid),
+                           libcfs_nid2str(export->exp_connection->c_peer.nid));
+               else
+                       /* New MDS connection from the same NID. */
+                       LCONSOLE_WARN("%s: Received new %s connection from "
+                               "%s, removing former export from same NID\n",
+                               target->obd_name, mds_conn ? "MDS" : "LWP",
+                               libcfs_nid2str(req->rq_peer.nid));
                 class_fail_export(export);
                 class_export_put(export);
                 export = NULL;
@@ -928,9 +995,8 @@ int target_handle_connect(struct ptlrpc_request *req)
                    req->rq_peer.nid != export->exp_connection->c_peer.nid &&
                    (lustre_msg_get_op_flags(req->rq_reqmsg) &
                     MSG_CONNECT_INITIAL)) {
-               cfs_spin_unlock(&export->exp_lock);
-                /* in mds failover we have static uuid but nid can be
-                 * changed*/
+               spin_unlock(&export->exp_lock);
+               /* In MDS failover we have static UUID but NID can change. */
                 LCONSOLE_WARN("%s: Client %s seen on new nid %s when "
                               "existing nid %s is already connected\n",
                               target->obd_name, cluuid.uuid,
@@ -942,7 +1008,7 @@ int target_handle_connect(struct ptlrpc_request *req)
                 export = NULL;
         } else {
                export->exp_connecting = 1;
-               cfs_spin_unlock(&export->exp_lock);
+               spin_unlock(&export->exp_lock);
                LASSERT(export->exp_obd == target);
 
                rc = target_handle_reconnect(&conn, export, &cluuid);
@@ -953,27 +1019,12 @@ int target_handle_connect(struct ptlrpc_request *req)
 no_export:
                 OBD_FAIL_TIMEOUT(OBD_FAIL_TGT_DELAY_CONNECT, 2 * obd_timeout);
         } else if (req->rq_export == NULL &&
-                   cfs_atomic_read(&export->exp_rpc_count) > 0) {
+                  atomic_read(&export->exp_rpc_count) > 0) {
                 LCONSOLE_WARN("%s: Client %s (at %s) refused connection, "
                               "still busy with %d references\n",
                               target->obd_name, cluuid.uuid,
                               libcfs_nid2str(req->rq_peer.nid),
-                              cfs_atomic_read(&export->exp_refcount));
-                GOTO(out, rc = -EBUSY);
-        } else if (req->rq_export != NULL &&
-                   (cfs_atomic_read(&export->exp_rpc_count) > 1)) {
-                /* the current connect rpc has increased exp_rpc_count */
-                LCONSOLE_WARN("%s: Client %s (at %s) refused reconnection, "
-                              "still busy with %d active RPCs\n",
-                              target->obd_name, cluuid.uuid,
-                              libcfs_nid2str(req->rq_peer.nid),
-                              cfs_atomic_read(&export->exp_rpc_count) - 1);
-                cfs_spin_lock(&export->exp_lock);
-                if (req->rq_export->exp_conn_cnt <
-                    lustre_msg_get_conn_cnt(req->rq_reqmsg))
-                        /* try to abort active requests */
-                        req->rq_export->exp_abort_active_req = 1;
-                cfs_spin_unlock(&export->exp_lock);
+                             atomic_read(&export->exp_refcount));
                 GOTO(out, rc = -EBUSY);
         } else if (lustre_msg_get_conn_cnt(req->rq_reqmsg) == 1) {
                 if (!strstr(cluuid.uuid, "mdt"))
@@ -997,13 +1048,13 @@ no_export:
               export, (long)cfs_time_current_sec(),
               export ? (long)export->exp_last_request_time : 0);
 
-        /* If this is the first time a client connects, reset the recovery
-        * timer. Discard lightweight connections which might be local */
+       /* If this is the first time a client connects, reset the recovery
+        * timer. Discard lightweight connections which might be local. */
        if (!lw_client && rc == 0 && target->obd_recovering)
-                check_and_start_recovery_timer(target, req, export == NULL);
+               check_and_start_recovery_timer(target, req, export == NULL);
 
-        /* We want to handle EALREADY but *not* -EALREADY from
-         * target_handle_reconnect(), return reconnection state in a flag */
+       /* We want to handle EALREADY but *not* -EALREADY from
+        * target_handle_reconnect(), return reconnection state in a flag. */
         if (rc == EALREADY) {
                 lustre_msg_add_op_flags(req->rq_repmsg, MSG_CONNECT_RECONNECT);
                 rc = 0;
@@ -1011,65 +1062,61 @@ no_export:
                 LASSERT(rc == 0);
         }
 
-        /* Tell the client if we support replayable requests */
+       /* Tell the client if we support replayable requests. */
         if (target->obd_replayable)
                 lustre_msg_add_op_flags(req->rq_repmsg, MSG_CONNECT_REPLAYABLE);
         client_nid = &req->rq_peer.nid;
 
         if (export == NULL) {
                /* allow lightweight connections during recovery */
-               if (target->obd_recovering && !lw_client) {
+               /* allow "new" MDT to be connected during recovery, since we
+                * need retrieve recovery update records from it */
+               if (target->obd_recovering && !lw_client && !mds_mds_conn) {
                         cfs_time_t t;
-                       int        c; /* connected */
-                       int        i; /* in progress */
-                       int        k; /* known */
+                       int     c; /* connected */
+                       int     i; /* in progress */
+                       int     k; /* known */
+                       int     s; /* stale/evicted */
 
-                       c = cfs_atomic_read(&target->obd_connected_clients);
-                       i = cfs_atomic_read(&target->obd_lock_replay_clients);
+                       c = atomic_read(&target->obd_connected_clients);
+                       i = atomic_read(&target->obd_lock_replay_clients);
                        k = target->obd_max_recoverable_clients;
+                       s = target->obd_stale_clients;
                        t = cfs_timer_deadline(&target->obd_recovery_timer);
                        t = cfs_time_sub(t, cfs_time_current());
                        t = cfs_duration_sec(t);
-                       LCONSOLE_WARN("%s: Denying connection for new client "
-                                     "%s (at %s), waiting for all %d known "
-                                     "clients (%d recovered, %d in progress, "
-                                     "and %d unseen) to recover in %d:%.02d\n",
+                       LCONSOLE_WARN("%s: Denying connection for new client %s"
+                                     "(at %s), waiting for %d known clients "
+                                     "(%d recovered, %d in progress, and %d "
+                                     "evicted) to recover in %d:%.02d\n",
                                      target->obd_name, cluuid.uuid,
                                      libcfs_nid2str(req->rq_peer.nid), k,
-                                     c - i, i, k - c, (int)t / 60,
+                                     c - i, i, s, (int)t / 60,
                                      (int)t % 60);
-                        rc = -EBUSY;
-                } else {
+                       rc = -EBUSY;
+               } else {
 dont_check_exports:
-                        rc = obd_connect(req->rq_svc_thread->t_env,
-                                         &export, target, &cluuid, data,
-                                         client_nid);
-                        if (rc == 0)
-                                conn.cookie = export->exp_handle.h_cookie;
-                }
-        } else {
-                rc = obd_reconnect(req->rq_svc_thread->t_env,
-                                   export, target, &cluuid, data, client_nid);
-        }
-        if (rc)
-                GOTO(out, rc);
-
-#if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(2, 6, 50, 0)
-       /* 2.2.0 clients always swab nidtbl entries due to a bug, so server
-        * will do the swabbing for if the client is using the same endianness.
-        *
-        * This fixup is version-limited, because we don't want to carry the
-        * OBD_CONNECT_MNE_SWAB flag around forever, just so long as we need
-        * interop with unpatched 2.2 clients.  For newer clients, servers
-        * will never do MNE swabbing, let the client handle that.  LU-1644 */
-       export->exp_need_mne_swab = !ptlrpc_req_need_swab(req) &&
-                       !(data->ocd_connect_flags & OBD_CONNECT_MNE_SWAB);
-#else
-#warning "LU-1644: Remove old OBD_CONNECT_MNE_SWAB fixup and exp_need_mne_swab"
-#endif
+                       rc = obd_connect(req->rq_svc_thread->t_env,
+                                        &export, target, &cluuid, data,
+                                        client_nid);
+                       if (mds_conn && OBD_FAIL_CHECK(OBD_FAIL_TGT_RCVG_FLAG))
+                               lustre_msg_add_op_flags(req->rq_repmsg,
+                                                       MSG_CONNECT_RECOVERING);
+                       if (rc == 0)
+                               conn.cookie = export->exp_handle.h_cookie;
+
+                       if (mds_mds_conn)
+                               new_mds_mds_conn = true;
+               }
+       } else {
+               rc = obd_reconnect(req->rq_svc_thread->t_env,
+                                  export, target, &cluuid, data, client_nid);
+       }
+       if (rc)
+               GOTO(out, rc);
 
-        LASSERT(target->u.obt.obt_magic == OBT_MAGIC);
-        data->ocd_instance = target->u.obt.obt_instance;
+       LASSERT(target->u.obt.obt_magic == OBT_MAGIC);
+       data->ocd_instance = target->u.obt.obt_instance;
 
         /* Return only the parts of obd_connect_data that we understand, so the
          * client knows that we don't understand the rest. */
@@ -1096,17 +1143,13 @@ dont_check_exports:
          * XXX this will go away when shaver stops sending the "connect" handle
          * in the real "remote handle" field of the request --phik 24 Apr 2003
          */
-        if (req->rq_export != NULL)
-                class_export_put(req->rq_export);
+       ptlrpc_request_change_export(req, export);
 
-       /* request takes one export refcount */
-       req->rq_export = class_export_get(export);
-
-        cfs_spin_lock(&export->exp_lock);
-        if (export->exp_conn_cnt >= lustre_msg_get_conn_cnt(req->rq_reqmsg)) {
-                cfs_spin_unlock(&export->exp_lock);
-                CDEBUG(D_RPCTRACE, "%s: %s already connected at higher "
-                       "conn_cnt: %d > %d\n",
+       spin_lock(&export->exp_lock);
+       if (export->exp_conn_cnt >= lustre_msg_get_conn_cnt(req->rq_reqmsg)) {
+               spin_unlock(&export->exp_lock);
+               CDEBUG(D_RPCTRACE, "%s: %s already connected at greater "
+                      "or equal conn_cnt: %d >= %d\n",
                        cluuid.uuid, libcfs_nid2str(req->rq_peer.nid),
                        export->exp_conn_cnt,
                        lustre_msg_get_conn_cnt(req->rq_reqmsg));
@@ -1115,24 +1158,23 @@ dont_check_exports:
         }
         LASSERT(lustre_msg_get_conn_cnt(req->rq_reqmsg) > 0);
         export->exp_conn_cnt = lustre_msg_get_conn_cnt(req->rq_reqmsg);
-        export->exp_abort_active_req = 0;
 
-        /* request from liblustre?  Don't evict it for not pinging. */
+       /* Don't evict liblustre clients for not pinging. */
         if (lustre_msg_get_op_flags(req->rq_reqmsg) & MSG_CONNECT_LIBCLIENT) {
                 export->exp_libclient = 1;
-                cfs_spin_unlock(&export->exp_lock);
+               spin_unlock(&export->exp_lock);
 
-                cfs_spin_lock(&target->obd_dev_lock);
-                cfs_list_del_init(&export->exp_obd_chain_timed);
-                cfs_spin_unlock(&target->obd_dev_lock);
-        } else {
-                cfs_spin_unlock(&export->exp_lock);
-        }
+               spin_lock(&target->obd_dev_lock);
+               list_del_init(&export->exp_obd_chain_timed);
+               spin_unlock(&target->obd_dev_lock);
+       } else {
+               spin_unlock(&export->exp_lock);
+       }
 
         if (export->exp_connection != NULL) {
-                /* Check to see if connection came from another NID */
+               /* Check to see if connection came from another NID. */
                 if ((export->exp_connection->c_peer.nid != req->rq_peer.nid) &&
-                    !cfs_hlist_unhashed(&export->exp_nid_hash))
+                   !hlist_unhashed(&export->exp_nid_hash))
                         cfs_hash_del(export->exp_obd->obd_nid_hash,
                                      &export->exp_connection->c_peer.nid,
                                      &export->exp_nid_hash);
@@ -1143,7 +1185,7 @@ dont_check_exports:
         export->exp_connection = ptlrpc_connection_get(req->rq_peer,
                                                        req->rq_self,
                                                        &remote_uuid);
-        if (cfs_hlist_unhashed(&export->exp_nid_hash)) {
+       if (hlist_unhashed(&export->exp_nid_hash)) {
                 cfs_hash_add(export->exp_obd->obd_nid_hash,
                              &export->exp_connection->c_peer.nid,
                              &export->exp_nid_hash);
@@ -1153,17 +1195,17 @@ dont_check_exports:
                 int has_transno;
                 __u64 transno = data->ocd_transno;
 
-                cfs_spin_lock(&export->exp_lock);
+               spin_lock(&export->exp_lock);
                /* possible race with class_disconnect_stale_exports,
                 * export may be already in the eviction process */
                if (export->exp_failed) {
-                       cfs_spin_unlock(&export->exp_lock);
+                       spin_unlock(&export->exp_lock);
                        GOTO(out, rc = -ENODEV);
                }
-                export->exp_in_recovery = 1;
-                export->exp_req_replay_needed = 1;
-                export->exp_lock_replay_needed = 1;
-                cfs_spin_unlock(&export->exp_lock);
+               export->exp_in_recovery = 1;
+               export->exp_req_replay_needed = 1;
+               export->exp_lock_replay_needed = 1;
+               spin_unlock(&export->exp_lock);
 
                 has_transno = !!(lustre_msg_get_op_flags(req->rq_reqmsg) &
                                  MSG_CONNECT_TRANSNO);
@@ -1173,20 +1215,27 @@ dont_check_exports:
                 if (has_transno && transno > 0 &&
                     transno < target->obd_next_recovery_transno &&
                     transno > target->obd_last_committed) {
-                        /* another way is to use cmpxchg() so it will be
-                         * lock free */
-                        cfs_spin_lock(&target->obd_recovery_task_lock);
-                        if (transno < target->obd_next_recovery_transno)
-                                target->obd_next_recovery_transno = transno;
-                        cfs_spin_unlock(&target->obd_recovery_task_lock);
+                       /* Another way is to use cmpxchg() to be lock-free. */
+                       spin_lock(&target->obd_recovery_task_lock);
+                       if (transno < target->obd_next_recovery_transno)
+                               target->obd_next_recovery_transno = transno;
+                       spin_unlock(&target->obd_recovery_task_lock);
                 }
 
-                cfs_atomic_inc(&target->obd_req_replay_clients);
-                cfs_atomic_inc(&target->obd_lock_replay_clients);
-                if (cfs_atomic_inc_return(&target->obd_connected_clients) ==
-                    target->obd_max_recoverable_clients)
-                        cfs_waitq_signal(&target->obd_next_transno_waitq);
-        }
+               atomic_inc(&target->obd_req_replay_clients);
+               atomic_inc(&target->obd_lock_replay_clients);
+               /* Note: MDS-MDS connection is allowed to be connected during
+                * recovery, no matter if the exports needs to be recoveried.
+                * Because we need retrieve updates logs from all other MDTs.
+                * So if the MDS-MDS export is new, obd_max_recoverable_clients
+                * also needs to be increased to match other recovery checking
+                * condition. */
+               if (new_mds_mds_conn)
+                       target->obd_max_recoverable_clients++;
+               if (atomic_inc_return(&target->obd_connected_clients) ==
+                   target->obd_max_recoverable_clients)
+                       wake_up(&target->obd_next_transno_waitq);
+       }
 
         /* Tell the client we're in recovery, when client is involved in it. */
        if (target->obd_recovering && !lw_client)
@@ -1195,25 +1244,19 @@ dont_check_exports:
         tmp = req_capsule_client_get(&req->rq_pill, &RMF_CONN);
         conn = *tmp;
 
-       /* for the rest part, we return -ENOTCONN in case of errors
-        * in order to let client initialize connection again.
-        */
+       /* Return -ENOTCONN in case of errors to let client reconnect. */
        revimp = class_new_import(target);
        if (revimp == NULL) {
                CERROR("fail to alloc new reverse import.\n");
                GOTO(out, rc = -ENOTCONN);
        }
 
-       cfs_spin_lock(&export->exp_lock);
-       if (export->exp_imp_reverse != NULL) {
+       spin_lock(&export->exp_lock);
+       if (export->exp_imp_reverse != NULL)
                /* destroyed import can be still referenced in ctxt */
-               obd_set_info_async(req->rq_svc_thread->t_env, export,
-                                  sizeof(KEY_REVIMP_UPD), KEY_REVIMP_UPD,
-                                  0, NULL, NULL);
                tmp_imp = export->exp_imp_reverse;
-       }
        export->exp_imp_reverse = revimp;
-       cfs_spin_unlock(&export->exp_lock);
+       spin_unlock(&export->exp_lock);
 
         revimp->imp_connection = ptlrpc_connection_addref(export->exp_connection);
         revimp->imp_client = &export->exp_obd->obd_ldlm_client;
@@ -1221,28 +1264,23 @@ dont_check_exports:
         revimp->imp_dlm_fake = 1;
         revimp->imp_state = LUSTRE_IMP_FULL;
 
-        /* unknown versions will be caught in
-         * ptlrpc_handle_server_req_in->lustre_unpack_msg() */
+       /* Unknown versions will be caught in
+        * ptlrpc_handle_server_req_in->lustre_unpack_msg(). */
         revimp->imp_msg_magic = req->rq_reqmsg->lm_magic;
 
-        if ((export->exp_connect_flags & OBD_CONNECT_AT) &&
-            (revimp->imp_msg_magic != LUSTRE_MSG_MAGIC_V1))
-                revimp->imp_msghdr_flags |= MSGHDR_AT_SUPPORT;
-        else
-                revimp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
+       if (data->ocd_connect_flags & OBD_CONNECT_AT)
+               revimp->imp_msghdr_flags |= MSGHDR_AT_SUPPORT;
+       else
+               revimp->imp_msghdr_flags &= ~MSGHDR_AT_SUPPORT;
 
-        if ((export->exp_connect_flags & OBD_CONNECT_FULL20) &&
-            (revimp->imp_msg_magic != LUSTRE_MSG_MAGIC_V1))
-                revimp->imp_msghdr_flags |= MSGHDR_CKSUM_INCOMPAT18;
-        else
-                revimp->imp_msghdr_flags &= ~MSGHDR_CKSUM_INCOMPAT18;
+       revimp->imp_msghdr_flags |= MSGHDR_CKSUM_INCOMPAT18;
 
        rc = sptlrpc_import_sec_adapt(revimp, req->rq_svc_ctx, &req->rq_flvr);
        if (rc) {
                CERROR("Failed to get sec for reverse import: %d\n", rc);
-               cfs_spin_lock(&export->exp_lock);
+               spin_lock(&export->exp_lock);
                export->exp_imp_reverse = NULL;
-               cfs_spin_unlock(&export->exp_lock);
+               spin_unlock(&export->exp_lock);
                class_destroy_import(revimp);
        }
 
@@ -1251,23 +1289,23 @@ dont_check_exports:
 out:
        if (tmp_imp != NULL)
                client_destroy_import(tmp_imp);
-        if (export) {
-                cfs_spin_lock(&export->exp_lock);
-                export->exp_connecting = 0;
-                cfs_spin_unlock(&export->exp_lock);
+       if (export) {
+               spin_lock(&export->exp_lock);
+               export->exp_connecting = 0;
+               spin_unlock(&export->exp_lock);
 
-                class_export_put(export);
-        }
-        if (targref) {
-               cfs_spin_lock(&target->obd_dev_lock);
+               class_export_put(export);
+       }
+       if (targref) {
+               spin_lock(&target->obd_dev_lock);
                target->obd_conn_inprogress--;
-               cfs_spin_unlock(&target->obd_dev_lock);
+               spin_unlock(&target->obd_dev_lock);
 
-                class_decref(targref, __FUNCTION__, cfs_current());
+               class_decref(targref, __func__, current);
        }
-        if (rc)
-                req->rq_status = rc;
-        RETURN(rc);
+       if (rc)
+               req->rq_status = rc;
+       RETURN(rc);
 }
 
 int target_handle_disconnect(struct ptlrpc_request *req)
@@ -1279,7 +1317,7 @@ int target_handle_disconnect(struct ptlrpc_request *req)
         if (rc)
                 RETURN(rc);
 
-        /* keep the rq_export around so we can send the reply */
+       /* Keep the rq_export around so we can send the reply. */
         req->rq_status = obd_disconnect(class_export_get(req->rq_export));
 
         RETURN(0);
@@ -1290,12 +1328,12 @@ void target_destroy_export(struct obd_export *exp)
        struct obd_import       *imp = NULL;
        /* exports created from last_rcvd data, and "fake"
           exports created by lctl don't have an import */
-       cfs_spin_lock(&exp->exp_lock);
+       spin_lock(&exp->exp_lock);
        if (exp->exp_imp_reverse != NULL) {
                imp = exp->exp_imp_reverse;
                exp->exp_imp_reverse = NULL;
        }
-       cfs_spin_unlock(&exp->exp_lock);
+       spin_unlock(&exp->exp_lock);
        if (imp != NULL)
                client_destroy_import(imp);
 
@@ -1304,30 +1342,31 @@ void target_destroy_export(struct obd_export *exp)
        LASSERT_ATOMIC_ZERO(&exp->exp_cb_count);
        LASSERT_ATOMIC_ZERO(&exp->exp_replay_count);
 }
+EXPORT_SYMBOL(target_destroy_export);
 
 /*
  * Recovery functions
  */
 static void target_request_copy_get(struct ptlrpc_request *req)
 {
-        class_export_rpc_get(req->rq_export);
-        LASSERT(cfs_list_empty(&req->rq_list));
-        CFS_INIT_LIST_HEAD(&req->rq_replay_list);
-
-        /* increase refcount to keep request in queue */
-        cfs_atomic_inc(&req->rq_refcount);
-        /** let export know it has replays to be handled */
-        cfs_atomic_inc(&req->rq_export->exp_replay_count);
+       class_export_rpc_inc(req->rq_export);
+       LASSERT(list_empty(&req->rq_list));
+       INIT_LIST_HEAD(&req->rq_replay_list);
+
+       /* Increase refcount to keep request in queue. */
+       atomic_inc(&req->rq_refcount);
+       /* Let export know it has replays to be handled. */
+       atomic_inc(&req->rq_export->exp_replay_count);
 }
 
 static void target_request_copy_put(struct ptlrpc_request *req)
 {
-        LASSERT(cfs_list_empty(&req->rq_replay_list));
-        LASSERT_ATOMIC_POS(&req->rq_export->exp_replay_count);
+       LASSERT(list_empty(&req->rq_replay_list));
+       LASSERT_ATOMIC_POS(&req->rq_export->exp_replay_count);
 
-        cfs_atomic_dec(&req->rq_export->exp_replay_count);
-        class_export_rpc_put(req->rq_export);
-        ptlrpc_server_drop_request(req);
+       atomic_dec(&req->rq_export->exp_replay_count);
+       class_export_rpc_dec(req->rq_export);
+       ptlrpc_server_drop_request(req);
 }
 
 static int target_exp_enqueue_req_replay(struct ptlrpc_request *req)
@@ -1339,8 +1378,8 @@ static int target_exp_enqueue_req_replay(struct ptlrpc_request *req)
 
         LASSERT(exp);
 
-        cfs_spin_lock(&exp->exp_lock);
-        cfs_list_for_each_entry(reqiter, &exp->exp_req_replay_queue,
+       spin_lock(&exp->exp_lock);
+       list_for_each_entry(reqiter, &exp->exp_req_replay_queue,
                                 rq_replay_list) {
                 if (lustre_msg_get_transno(reqiter->rq_reqmsg) == transno) {
                         dup = 1;
@@ -1349,36 +1388,36 @@ static int target_exp_enqueue_req_replay(struct ptlrpc_request *req)
         }
 
         if (dup) {
-                /* we expect it with RESENT and REPLAY flags */
+               /* We expect it with RESENT and REPLAY flags. */
                 if ((lustre_msg_get_flags(req->rq_reqmsg) &
                      (MSG_RESENT | MSG_REPLAY)) != (MSG_RESENT | MSG_REPLAY))
                         CERROR("invalid flags %x of resent replay\n",
                                lustre_msg_get_flags(req->rq_reqmsg));
         } else {
-                cfs_list_add_tail(&req->rq_replay_list,
+               list_add_tail(&req->rq_replay_list,
                                   &exp->exp_req_replay_queue);
         }
 
-        cfs_spin_unlock(&exp->exp_lock);
+       spin_unlock(&exp->exp_lock);
         return dup;
 }
 
 static void target_exp_dequeue_req_replay(struct ptlrpc_request *req)
 {
-        LASSERT(!cfs_list_empty(&req->rq_replay_list));
-        LASSERT(req->rq_export);
+       LASSERT(!list_empty(&req->rq_replay_list));
+       LASSERT(req->rq_export);
 
-        cfs_spin_lock(&req->rq_export->exp_lock);
-        cfs_list_del_init(&req->rq_replay_list);
-        cfs_spin_unlock(&req->rq_export->exp_lock);
+       spin_lock(&req->rq_export->exp_lock);
+       list_del_init(&req->rq_replay_list);
+       spin_unlock(&req->rq_export->exp_lock);
 }
 
-#ifdef __KERNEL__
-static void target_finish_recovery(struct obd_device *obd)
+static void target_finish_recovery(struct lu_target *lut)
 {
+       struct obd_device *obd = lut->lut_obd;
         ENTRY;
 
-       /* only log a recovery message when recovery has occurred */
+       /* Only log a recovery message when recovery has occurred. */
        if (obd->obd_recovery_start) {
                time_t elapsed_time = max_t(time_t, 1, cfs_time_current_sec() -
                                        obd->obd_recovery_start);
@@ -1386,31 +1425,35 @@ static void target_finish_recovery(struct obd_device *obd)
                        "%d recovered and %d %s evicted.\n", obd->obd_name,
                        (int)elapsed_time / 60, (int)elapsed_time % 60,
                        obd->obd_max_recoverable_clients,
-                       cfs_atomic_read(&obd->obd_connected_clients),
+                       atomic_read(&obd->obd_connected_clients),
                        obd->obd_stale_clients,
                        obd->obd_stale_clients == 1 ? "was" : "were");
        }
 
         ldlm_reprocess_all_ns(obd->obd_namespace);
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (!cfs_list_empty(&obd->obd_req_replay_queue) ||
-            !cfs_list_empty(&obd->obd_lock_replay_queue) ||
-            !cfs_list_empty(&obd->obd_final_req_queue)) {
+       spin_lock(&obd->obd_recovery_task_lock);
+       if (!list_empty(&obd->obd_req_replay_queue) ||
+           !list_empty(&obd->obd_lock_replay_queue) ||
+           !list_empty(&obd->obd_final_req_queue)) {
                 CERROR("%s: Recovery queues ( %s%s%s) are not empty\n",
                        obd->obd_name,
-                       cfs_list_empty(&obd->obd_req_replay_queue) ? "" : "req ",
-                       cfs_list_empty(&obd->obd_lock_replay_queue) ? \
+                      list_empty(&obd->obd_req_replay_queue) ? "" : "req ",
+                      list_empty(&obd->obd_lock_replay_queue) ? \
                                "" : "lock ",
-                       cfs_list_empty(&obd->obd_final_req_queue) ? \
+                      list_empty(&obd->obd_final_req_queue) ? \
                                "" : "final ");
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                LBUG();
-        }
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
+               spin_unlock(&obd->obd_recovery_task_lock);
+               LBUG();
+       }
+       spin_unlock(&obd->obd_recovery_task_lock);
+
+       if (lut->lut_tdtd != NULL &&
+           !list_empty(&lut->lut_tdtd->tdtd_replay_list))
+               dtrq_list_dump(lut->lut_tdtd, D_ERROR);
 
         obd->obd_recovery_end = cfs_time_current_sec();
 
-        /* when recovery finished, cleanup orphans on mds and ost */
+       /* When recovery finished, cleanup orphans on MDS and OST. */
         if (OBT(obd) && OBP(obd, postrecov)) {
                 int rc = OBP(obd, postrecov)(obd);
                 if (rc < 0)
@@ -1422,14 +1465,14 @@ static void target_finish_recovery(struct obd_device *obd)
 
 static void abort_req_replay_queue(struct obd_device *obd)
 {
-        struct ptlrpc_request *req, *n;
-        cfs_list_t abort_list;
-
-        CFS_INIT_LIST_HEAD(&abort_list);
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        cfs_list_splice_init(&obd->obd_req_replay_queue, &abort_list);
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        cfs_list_for_each_entry_safe(req, n, &abort_list, rq_list) {
+       struct ptlrpc_request *req, *n;
+       struct list_head abort_list;
+
+       INIT_LIST_HEAD(&abort_list);
+       spin_lock(&obd->obd_recovery_task_lock);
+       list_splice_init(&obd->obd_req_replay_queue, &abort_list);
+       spin_unlock(&obd->obd_recovery_task_lock);
+       list_for_each_entry_safe(req, n, &abort_list, rq_list) {
                 DEBUG_REQ(D_WARNING, req, "aborted:");
                 req->rq_status = -ENOTCONN;
                 if (ptlrpc_error(req)) {
@@ -1443,14 +1486,14 @@ static void abort_req_replay_queue(struct obd_device *obd)
 
 static void abort_lock_replay_queue(struct obd_device *obd)
 {
-        struct ptlrpc_request *req, *n;
-        cfs_list_t abort_list;
-
-        CFS_INIT_LIST_HEAD(&abort_list);
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        cfs_list_splice_init(&obd->obd_lock_replay_queue, &abort_list);
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        cfs_list_for_each_entry_safe(req, n, &abort_list, rq_list){
+       struct ptlrpc_request *req, *n;
+       struct list_head abort_list;
+
+       INIT_LIST_HEAD(&abort_list);
+       spin_lock(&obd->obd_recovery_task_lock);
+       list_splice_init(&obd->obd_lock_replay_queue, &abort_list);
+       spin_unlock(&obd->obd_recovery_task_lock);
+       list_for_each_entry_safe(req, n, &abort_list, rq_list) {
                 DEBUG_REQ(D_ERROR, req, "aborted:");
                 req->rq_status = -ENOTCONN;
                 if (ptlrpc_error(req)) {
@@ -1473,42 +1516,44 @@ static void abort_lock_replay_queue(struct obd_device *obd)
 void target_cleanup_recovery(struct obd_device *obd)
 {
         struct ptlrpc_request *req, *n;
-        cfs_list_t clean_list;
+       struct list_head clean_list;
         ENTRY;
 
-        CFS_INIT_LIST_HEAD(&clean_list);
-        cfs_spin_lock(&obd->obd_dev_lock);
-        if (!obd->obd_recovering) {
-                cfs_spin_unlock(&obd->obd_dev_lock);
-                EXIT;
-                return;
-        }
-        obd->obd_recovering = obd->obd_abort_recovery = 0;
-        cfs_spin_unlock(&obd->obd_dev_lock);
-
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        target_cancel_recovery_timer(obd);
-        cfs_list_splice_init(&obd->obd_req_replay_queue, &clean_list);
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-
-        cfs_list_for_each_entry_safe(req, n, &clean_list, rq_list) {
-                LASSERT(req->rq_reply_state == 0);
-                target_exp_dequeue_req_replay(req);
-                target_request_copy_put(req);
-        }
+       INIT_LIST_HEAD(&clean_list);
+       spin_lock(&obd->obd_dev_lock);
+       if (!obd->obd_recovering) {
+               spin_unlock(&obd->obd_dev_lock);
+               EXIT;
+               return;
+       }
+       obd->obd_recovering = obd->obd_abort_recovery = 0;
+       obd->obd_force_abort_recovery = 0;
+       spin_unlock(&obd->obd_dev_lock);
+
+       spin_lock(&obd->obd_recovery_task_lock);
+       target_cancel_recovery_timer(obd);
+       list_splice_init(&obd->obd_req_replay_queue, &clean_list);
+       spin_unlock(&obd->obd_recovery_task_lock);
+
+       list_for_each_entry_safe(req, n, &clean_list, rq_list) {
+               LASSERT(req->rq_reply_state == NULL);
+               target_exp_dequeue_req_replay(req);
+               target_request_copy_put(req);
+       }
 
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        cfs_list_splice_init(&obd->obd_lock_replay_queue, &clean_list);
-        cfs_list_splice_init(&obd->obd_final_req_queue, &clean_list);
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
+       spin_lock(&obd->obd_recovery_task_lock);
+       list_splice_init(&obd->obd_lock_replay_queue, &clean_list);
+       list_splice_init(&obd->obd_final_req_queue, &clean_list);
+       spin_unlock(&obd->obd_recovery_task_lock);
 
-        cfs_list_for_each_entry_safe(req, n, &clean_list, rq_list){
-                LASSERT(req->rq_reply_state == 0);
+       list_for_each_entry_safe(req, n, &clean_list, rq_list) {
+               LASSERT(req->rq_reply_state == NULL);
                 target_request_copy_put(req);
         }
 
         EXIT;
 }
+EXPORT_SYMBOL(target_cleanup_recovery);
 
 /* obd_recovery_task_lock should be held */
 void target_cancel_recovery_timer(struct obd_device *obd)
@@ -1519,26 +1564,27 @@ void target_cancel_recovery_timer(struct obd_device *obd)
 
 static void target_start_recovery_timer(struct obd_device *obd)
 {
-        if (obd->obd_recovery_start != 0)
-                return;
-
-        cfs_spin_lock(&obd->obd_dev_lock);
-        if (!obd->obd_recovering || obd->obd_abort_recovery) {
-                cfs_spin_unlock(&obd->obd_dev_lock);
-                return;
-        }
+       if (obd->obd_recovery_start != 0)
+               return;
+
+       spin_lock(&obd->obd_dev_lock);
+       if (!obd->obd_recovering || obd->obd_abort_recovery ||
+           obd->obd_force_abort_recovery) {
+               spin_unlock(&obd->obd_dev_lock);
+               return;
+       }
 
-        LASSERT(obd->obd_recovery_timeout != 0);
+       LASSERT(obd->obd_recovery_timeout != 0);
 
-        if (obd->obd_recovery_start != 0) {
-                cfs_spin_unlock(&obd->obd_dev_lock);
-                return;
-        }
+       if (obd->obd_recovery_start != 0) {
+               spin_unlock(&obd->obd_dev_lock);
+               return;
+       }
 
-        cfs_timer_arm(&obd->obd_recovery_timer,
-                      cfs_time_shift(obd->obd_recovery_timeout));
-        obd->obd_recovery_start = cfs_time_current_sec();
-        cfs_spin_unlock(&obd->obd_dev_lock);
+       cfs_timer_arm(&obd->obd_recovery_timer,
+                     cfs_time_shift(obd->obd_recovery_timeout));
+       obd->obd_recovery_start = cfs_time_current_sec();
+       spin_unlock(&obd->obd_dev_lock);
 
         LCONSOLE_WARN("%s: Will be in recovery for at least %d:%.02d, "
                       "or until %d client%s reconnect%s\n",
@@ -1558,14 +1604,15 @@ static void target_start_recovery_timer(struct obd_device *obd)
  */
 static void extend_recovery_timer(struct obd_device *obd, int drt, bool extend)
 {
-        cfs_time_t now;
-        cfs_time_t end;
-        cfs_duration_t left;
-        int to;
-
-        cfs_spin_lock(&obd->obd_dev_lock);
-        if (!obd->obd_recovering || obd->obd_abort_recovery) {
-                cfs_spin_unlock(&obd->obd_dev_lock);
+       cfs_time_t now;
+       cfs_time_t end;
+       cfs_duration_t left;
+       int to;
+
+       spin_lock(&obd->obd_dev_lock);
+       if (!obd->obd_recovering || obd->obd_abort_recovery ||
+           obd->obd_force_abort_recovery) {
+               spin_unlock(&obd->obd_dev_lock);
                 return;
         }
         LASSERT(obd->obd_recovery_start != 0);
@@ -1579,21 +1626,20 @@ static void extend_recovery_timer(struct obd_device *obd, int drt, bool extend)
                 to += drt - left;
         } else if (!extend && (drt > to)) {
                 to = drt;
-                /* reduce drt by already passed time */
-                drt -= obd->obd_recovery_timeout - left;
         }
 
         if (to > obd->obd_recovery_time_hard)
                 to = obd->obd_recovery_time_hard;
-        if (obd->obd_recovery_timeout < to) {
+       if (obd->obd_recovery_timeout < to) {
                 obd->obd_recovery_timeout = to;
-                cfs_timer_arm(&obd->obd_recovery_timer,
-                              cfs_time_shift(drt));
+               end = obd->obd_recovery_start + to;
+               cfs_timer_arm(&obd->obd_recovery_timer,
+                               cfs_time_shift(end - now));
         }
-        cfs_spin_unlock(&obd->obd_dev_lock);
+       spin_unlock(&obd->obd_dev_lock);
 
-        CDEBUG(D_HA, "%s: recovery timer will expire in %u seconds\n",
-               obd->obd_name, (unsigned)drt);
+       CDEBUG(D_HA, "%s: recovery timer will expire in %u seconds\n",
+               obd->obd_name, (unsigned)cfs_time_sub(end, now));
 }
 
 /* Reset the timer with each new client connection */
@@ -1614,7 +1660,6 @@ check_and_start_recovery_timer(struct obd_device *obd,
 {
         int service_time = lustre_msg_get_service_time(req->rq_reqmsg);
         struct obd_device_target *obt = &obd->u.obt;
-        struct lustre_sb_info *lsi;
 
         if (!new_client && service_time)
                 /* Teach server about old server's estimates, as first guess
@@ -1624,22 +1669,19 @@ check_and_start_recovery_timer(struct obd_device *obd,
 
         target_start_recovery_timer(obd);
 
-        /* convert the service time to rpc timeout,
-         * reuse service_time to limit stack usage */
-        service_time = at_est2timeout(service_time);
+       /* Convert the service time to RPC timeout,
+        * and reuse service_time to limit stack usage. */
+       service_time = at_est2timeout(service_time);
 
-        /* We expect other clients to timeout within service_time, then try
-         * to reconnect, then try the failover server.  The max delay between
-         * connect attempts is SWITCH_MAX + SWITCH_INC + INITIAL */
+       /* We expect other clients to timeout within service_time, then try
+        * to reconnect, then try the failover server.  The max delay between
+        * connect attempts is SWITCH_MAX + SWITCH_INC + INITIAL. */
         service_time += 2 * INITIAL_CONNECT_TIMEOUT;
 
         LASSERT(obt->obt_magic == OBT_MAGIC);
-        lsi = s2lsi(obt->obt_sb);
-       if (!(lsi->lsi_flags | LDD_F_IR_CAPABLE))
-                service_time += 2 * (CONNECTION_SWITCH_MAX +
-                                     CONNECTION_SWITCH_INC);
-        if (service_time > obd->obd_recovery_timeout && !new_client)
-                extend_recovery_timer(obd, service_time, false);
+       service_time += 2 * (CONNECTION_SWITCH_MAX + CONNECTION_SWITCH_INC);
+       if (service_time > obd->obd_recovery_timeout && !new_client)
+               extend_recovery_timer(obd, service_time, false);
 }
 
 /** Health checking routines */
@@ -1651,14 +1693,14 @@ static inline int exp_connect_healthy(struct obd_export *exp)
 /** if export done req_replay or has replay in queue */
 static inline int exp_req_replay_healthy(struct obd_export *exp)
 {
-        return (!exp->exp_req_replay_needed ||
-                cfs_atomic_read(&exp->exp_replay_count) > 0);
+       return (!exp->exp_req_replay_needed ||
+               atomic_read(&exp->exp_replay_count) > 0);
 }
 /** if export done lock_replay or has replay in queue */
 static inline int exp_lock_replay_healthy(struct obd_export *exp)
 {
-        return (!exp->exp_lock_replay_needed ||
-                cfs_atomic_read(&exp->exp_replay_count) > 0);
+       return (!exp->exp_lock_replay_needed ||
+               atomic_read(&exp->exp_replay_count) > 0);
 }
 
 static inline int exp_vbr_healthy(struct obd_export *exp)
@@ -1671,107 +1713,105 @@ static inline int exp_finished(struct obd_export *exp)
         return (exp->exp_in_recovery && !exp->exp_lock_replay_needed);
 }
 
-/** Checking routines for recovery */
-static int check_for_clients(struct obd_device *obd)
+static int check_for_next_transno(struct lu_target *lut)
 {
-        unsigned int clnts = cfs_atomic_read(&obd->obd_connected_clients);
+       struct ptlrpc_request *req = NULL;
+       struct obd_device *obd = lut->lut_obd;
+       int wake_up = 0, connected, completed, queue_len;
+       __u64 req_transno = 0;
+       __u64 update_transno = 0;
+       __u64 next_transno = 0;
+       ENTRY;
 
-        if (obd->obd_abort_recovery || obd->obd_recovery_expired)
-                return 1;
-        LASSERT(clnts <= obd->obd_max_recoverable_clients);
-        if (obd->obd_no_conn == 0 &&
-            clnts + obd->obd_stale_clients == obd->obd_max_recoverable_clients)
-                return 1;
-        return 0;
-}
+       spin_lock(&obd->obd_recovery_task_lock);
+       if (!list_empty(&obd->obd_req_replay_queue)) {
+               req = list_entry(obd->obd_req_replay_queue.next,
+                                    struct ptlrpc_request, rq_list);
+               req_transno = lustre_msg_get_transno(req->rq_reqmsg);
+       }
 
-static int check_for_next_transno(struct obd_device *obd)
-{
-        struct ptlrpc_request *req = NULL;
-        int wake_up = 0, connected, completed, queue_len;
-        __u64 next_transno, req_transno;
-        ENTRY;
+       if (lut->lut_tdtd != NULL) {
+               struct target_distribute_txn_data *tdtd;
+               __u64 update_transno;
 
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (!cfs_list_empty(&obd->obd_req_replay_queue)) {
-                req = cfs_list_entry(obd->obd_req_replay_queue.next,
-                                     struct ptlrpc_request, rq_list);
-                req_transno = lustre_msg_get_transno(req->rq_reqmsg);
-        } else {
-                req_transno = 0;
-        }
+               tdtd = lut->lut_tdtd;
+               update_transno = distribute_txn_get_next_transno(lut->lut_tdtd);
+       }
 
-        connected = cfs_atomic_read(&obd->obd_connected_clients);
-        completed = connected - cfs_atomic_read(&obd->obd_req_replay_clients);
-        queue_len = obd->obd_requests_queued_for_recovery;
-        next_transno = obd->obd_next_recovery_transno;
-
-        CDEBUG(D_HA, "max: %d, connected: %d, completed: %d, queue_len: %d, "
-               "req_transno: "LPU64", next_transno: "LPU64"\n",
-               obd->obd_max_recoverable_clients, connected, completed,
-               queue_len, req_transno, next_transno);
-
-        if (obd->obd_abort_recovery) {
-                CDEBUG(D_HA, "waking for aborted recovery\n");
-                wake_up = 1;
-        } else if (obd->obd_recovery_expired) {
-                CDEBUG(D_HA, "waking for expired recovery\n");
-                wake_up = 1;
-        } else if (cfs_atomic_read(&obd->obd_req_replay_clients) == 0) {
-                CDEBUG(D_HA, "waking for completed recovery\n");
-                wake_up = 1;
-        } else if (req_transno == next_transno) {
-                CDEBUG(D_HA, "waking for next ("LPD64")\n", next_transno);
-                wake_up = 1;
-        } else if (queue_len == cfs_atomic_read(&obd->obd_req_replay_clients)) {
-                int d_lvl = D_HA;
-                /** handle gaps occured due to lost reply or VBR */
-                LASSERTF(req_transno >= next_transno,
-                         "req_transno: "LPU64", next_transno: "LPU64"\n",
-                         req_transno, next_transno);
-                if (req_transno > obd->obd_last_committed &&
-                    !obd->obd_version_recov)
-                        d_lvl = D_ERROR;
-                CDEBUG(d_lvl,
-                       "%s: waking for gap in transno, VBR is %s (skip: "
-                       LPD64", ql: %d, comp: %d, conn: %d, next: "LPD64
-                       ", last_committed: "LPD64")\n",
-                       obd->obd_name, obd->obd_version_recov ? "ON" : "OFF",
-                       next_transno, queue_len, completed, connected,
-                       req_transno, obd->obd_last_committed);
-                obd->obd_next_recovery_transno = req_transno;
-                wake_up = 1;
-        } else if (OBD_FAIL_CHECK(OBD_FAIL_MDS_RECOVERY_ACCEPTS_GAPS)) {
-                CDEBUG(D_HA, "accepting transno gaps is explicitly allowed"
-                       " by fail_lock, waking up ("LPD64")\n", next_transno);
-                obd->obd_next_recovery_transno = req_transno;
-                wake_up = 1;
-        }
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        return wake_up;
-}
-
-static int check_for_next_lock(struct obd_device *obd)
-{
-        int wake_up = 0;
-
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (!cfs_list_empty(&obd->obd_lock_replay_queue)) {
-                CDEBUG(D_HA, "waking for next lock\n");
-                wake_up = 1;
-        } else if (cfs_atomic_read(&obd->obd_lock_replay_clients) == 0) {
-                CDEBUG(D_HA, "waking for completed lock replay\n");
-                wake_up = 1;
-        } else if (obd->obd_abort_recovery) {
-                CDEBUG(D_HA, "waking for aborted recovery\n");
-                wake_up = 1;
-        } else if (obd->obd_recovery_expired) {
-                CDEBUG(D_HA, "waking for expired recovery\n");
-                wake_up = 1;
-        }
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
+       connected = atomic_read(&obd->obd_connected_clients);
+       completed = connected - atomic_read(&obd->obd_req_replay_clients);
+       queue_len = obd->obd_requests_queued_for_recovery;
+       next_transno = obd->obd_next_recovery_transno;
+
+       CDEBUG(D_HA, "max: %d, connected: %d, completed: %d, queue_len: %d, "
+              "req_transno: "LPU64", next_transno: "LPU64"\n",
+              obd->obd_max_recoverable_clients, connected, completed,
+              queue_len, req_transno, next_transno);
+
+       if (obd->obd_abort_recovery || obd->obd_force_abort_recovery) {
+               CDEBUG(D_HA, "waking for aborted recovery\n");
+               wake_up = 1;
+       } else if (obd->obd_recovery_expired) {
+               CDEBUG(D_HA, "waking for expired recovery\n");
+               wake_up = 1;
+       } else if (req_transno == next_transno || (update_transno != 0 &&
+                                          update_transno <= next_transno)) {
+               CDEBUG(D_HA, "waking for next ("LPD64")\n", next_transno);
+               wake_up = 1;
+       } else if (queue_len > 0 &&
+                  queue_len == atomic_read(&obd->obd_req_replay_clients)) {
+               int d_lvl = D_HA;
+               /** handle gaps occured due to lost reply or VBR */
+               LASSERTF(req_transno >= next_transno,
+                        "req_transno: "LPU64", next_transno: "LPU64"\n",
+                        req_transno, next_transno);
+               if (req_transno > obd->obd_last_committed &&
+                   !obd->obd_version_recov)
+                       d_lvl = D_ERROR;
+               CDEBUG(d_lvl,
+                      "%s: waking for gap in transno, VBR is %s (skip: "
+                      LPD64", ql: %d, comp: %d, conn: %d, next: "LPD64
+                      ", next_update "LPD64" last_committed: "LPD64")\n",
+                      obd->obd_name, obd->obd_version_recov ? "ON" : "OFF",
+                      next_transno, queue_len, completed, connected,
+                      req_transno, update_transno, obd->obd_last_committed);
+               obd->obd_next_recovery_transno = req_transno;
+               wake_up = 1;
+       } else if (atomic_read(&obd->obd_req_replay_clients) == 0) {
+               CDEBUG(D_HA, "waking for completed recovery\n");
+               wake_up = 1;
+       } else if (OBD_FAIL_CHECK(OBD_FAIL_MDS_RECOVERY_ACCEPTS_GAPS)) {
+               CDEBUG(D_HA, "accepting transno gaps is explicitly allowed"
+                      " by fail_lock, waking up ("LPD64")\n", next_transno);
+               obd->obd_next_recovery_transno = req_transno;
+               wake_up = 1;
+       }
+       spin_unlock(&obd->obd_recovery_task_lock);
+       return wake_up;
+}
 
-        return wake_up;
+static int check_for_next_lock(struct lu_target *lut)
+{
+       struct obd_device *obd = lut->lut_obd;
+       int wake_up = 0;
+
+       spin_lock(&obd->obd_recovery_task_lock);
+       if (!list_empty(&obd->obd_lock_replay_queue)) {
+               CDEBUG(D_HA, "waking for next lock\n");
+               wake_up = 1;
+       } else if (atomic_read(&obd->obd_lock_replay_clients) == 0) {
+               CDEBUG(D_HA, "waking for completed lock replay\n");
+               wake_up = 1;
+       } else if (obd->obd_abort_recovery || obd->obd_force_abort_recovery) {
+               CDEBUG(D_HA, "waking for aborted recovery\n");
+               wake_up = 1;
+       } else if (obd->obd_recovery_expired) {
+               CDEBUG(D_HA, "waking for expired recovery\n");
+               wake_up = 1;
+       }
+       spin_unlock(&obd->obd_recovery_task_lock);
+
+       return wake_up;
 }
 
 /**
@@ -1779,148 +1819,119 @@ static int check_for_next_lock(struct obd_device *obd)
  * check its status with help of check_routine
  * evict dead clients via health_check
  */
-static int target_recovery_overseer(struct obd_device *obd,
-                                    int (*check_routine)(struct obd_device *),
-                                    int (*health_check)(struct obd_export *))
+static int target_recovery_overseer(struct lu_target *lut,
+                                   int (*check_routine)(struct lu_target *),
+                                   int (*health_check)(struct obd_export *))
 {
+       struct obd_device       *obd = lut->lut_obd;
 repeat:
-        cfs_wait_event(obd->obd_next_transno_waitq, check_routine(obd));
-        if (obd->obd_abort_recovery) {
-                CWARN("recovery is aborted, evict exports in recovery\n");
-                /** evict exports which didn't finish recovery yet */
-                class_disconnect_stale_exports(obd, exp_finished);
-                return 1;
-        } else if (obd->obd_recovery_expired) {
-                obd->obd_recovery_expired = 0;
-                /** If some clients died being recovered, evict them */
-                LCONSOLE_WARN("%s: recovery is timed out, "
-                              "evict stale exports\n", obd->obd_name);
-                /** evict cexports with no replay in queue, they are stalled */
-                class_disconnect_stale_exports(obd, health_check);
-                /** continue with VBR */
-                cfs_spin_lock(&obd->obd_dev_lock);
-                obd->obd_version_recov = 1;
-                cfs_spin_unlock(&obd->obd_dev_lock);
-                /**
-                 * reset timer, recovery will proceed with versions now,
-                 * timeout is set just to handle reconnection delays
-                 */
-                extend_recovery_timer(obd, RECONNECT_DELAY_MAX, true);
-                /** Wait for recovery events again, after evicting bad clients */
-                goto repeat;
-        }
-        return 0;
-}
-
-static struct ptlrpc_request *target_next_replay_req(struct obd_device *obd)
-{
-        struct ptlrpc_request *req = NULL;
-        ENTRY;
+       if ((obd->obd_recovery_start != 0) && (cfs_time_current_sec() >=
+             (obd->obd_recovery_start + obd->obd_recovery_time_hard))) {
+               CWARN("recovery is aborted by hard timeout\n");
+               obd->obd_abort_recovery = 1;
+       }
 
-        CDEBUG(D_HA, "Waiting for transno "LPD64"\n",
-               obd->obd_next_recovery_transno);
+       while (wait_event_timeout(obd->obd_next_transno_waitq,
+                                 check_routine(lut),
+                                 msecs_to_jiffies(60 * MSEC_PER_SEC)) == 0)
+               /* wait indefinitely for event, but don't trigger watchdog */;
 
-        if (target_recovery_overseer(obd, check_for_next_transno,
-                                     exp_req_replay_healthy)) {
-                abort_req_replay_queue(obd);
-                abort_lock_replay_queue(obd);
-        }
-
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (!cfs_list_empty(&obd->obd_req_replay_queue)) {
-                req = cfs_list_entry(obd->obd_req_replay_queue.next,
-                                     struct ptlrpc_request, rq_list);
-                cfs_list_del_init(&req->rq_list);
-                obd->obd_requests_queued_for_recovery--;
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        } else {
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                LASSERT(cfs_list_empty(&obd->obd_req_replay_queue));
-                LASSERT(cfs_atomic_read(&obd->obd_req_replay_clients) == 0);
-                /** evict exports failed VBR */
-                class_disconnect_stale_exports(obd, exp_vbr_healthy);
-        }
-        RETURN(req);
+       if (obd->obd_abort_recovery || obd->obd_force_abort_recovery) {
+               CWARN("recovery is aborted, evict exports in recovery\n");
+               /** evict exports which didn't finish recovery yet */
+               class_disconnect_stale_exports(obd, exp_finished);
+               return 1;
+       } else if (obd->obd_recovery_expired) {
+               obd->obd_recovery_expired = 0;
+               /** If some clients died being recovered, evict them */
+               LCONSOLE_WARN("%s: recovery is timed out, "
+                             "evict stale exports\n", obd->obd_name);
+               /** evict cexports with no replay in queue, they are stalled */
+               class_disconnect_stale_exports(obd, health_check);
+               /** continue with VBR */
+               spin_lock(&obd->obd_dev_lock);
+               obd->obd_version_recov = 1;
+               spin_unlock(&obd->obd_dev_lock);
+               /**
+                * reset timer, recovery will proceed with versions now,
+                * timeout is set just to handle reconnection delays
+                */
+               extend_recovery_timer(obd, RECONNECT_DELAY_MAX, true);
+               /** Wait for recovery events again, after evicting bad clients */
+               goto repeat;
+       }
+       return 0;
 }
 
-static struct ptlrpc_request *target_next_replay_lock(struct obd_device *obd)
+static struct ptlrpc_request *target_next_replay_lock(struct lu_target *lut)
 {
-        struct ptlrpc_request *req = NULL;
-
-        CDEBUG(D_HA, "Waiting for lock\n");
-        if (target_recovery_overseer(obd, check_for_next_lock,
-                                     exp_lock_replay_healthy))
-                abort_lock_replay_queue(obd);
-
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (!cfs_list_empty(&obd->obd_lock_replay_queue)) {
-                req = cfs_list_entry(obd->obd_lock_replay_queue.next,
-                                     struct ptlrpc_request, rq_list);
-                cfs_list_del_init(&req->rq_list);
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        } else {
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                LASSERT(cfs_list_empty(&obd->obd_lock_replay_queue));
-                LASSERT(cfs_atomic_read(&obd->obd_lock_replay_clients) == 0);
-                /** evict exports failed VBR */
-                class_disconnect_stale_exports(obd, exp_vbr_healthy);
-        }
-        return req;
+       struct obd_device       *obd = lut->lut_obd;
+       struct ptlrpc_request *req = NULL;
+
+       CDEBUG(D_HA, "Waiting for lock\n");
+       if (target_recovery_overseer(lut, check_for_next_lock,
+                                    exp_lock_replay_healthy))
+               abort_lock_replay_queue(obd);
+
+       spin_lock(&obd->obd_recovery_task_lock);
+       if (!list_empty(&obd->obd_lock_replay_queue)) {
+               req = list_entry(obd->obd_lock_replay_queue.next,
+                                    struct ptlrpc_request, rq_list);
+               list_del_init(&req->rq_list);
+               spin_unlock(&obd->obd_recovery_task_lock);
+       } else {
+               spin_unlock(&obd->obd_recovery_task_lock);
+               LASSERT(list_empty(&obd->obd_lock_replay_queue));
+               LASSERT(atomic_read(&obd->obd_lock_replay_clients) == 0);
+               /** evict exports failed VBR */
+               class_disconnect_stale_exports(obd, exp_vbr_healthy);
+       }
+       return req;
 }
 
 static struct ptlrpc_request *target_next_final_ping(struct obd_device *obd)
 {
-        struct ptlrpc_request *req = NULL;
-
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (!cfs_list_empty(&obd->obd_final_req_queue)) {
-                req = cfs_list_entry(obd->obd_final_req_queue.next,
-                                     struct ptlrpc_request, rq_list);
-                cfs_list_del_init(&req->rq_list);
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                if (req->rq_export->exp_in_recovery) {
-                        cfs_spin_lock(&req->rq_export->exp_lock);
-                        req->rq_export->exp_in_recovery = 0;
-                        cfs_spin_unlock(&req->rq_export->exp_lock);
-                }
-        } else {
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        }
-        return req;
+       struct ptlrpc_request *req = NULL;
+
+       spin_lock(&obd->obd_recovery_task_lock);
+       if (!list_empty(&obd->obd_final_req_queue)) {
+               req = list_entry(obd->obd_final_req_queue.next,
+                                    struct ptlrpc_request, rq_list);
+               list_del_init(&req->rq_list);
+               spin_unlock(&obd->obd_recovery_task_lock);
+               if (req->rq_export->exp_in_recovery) {
+                       spin_lock(&req->rq_export->exp_lock);
+                       req->rq_export->exp_in_recovery = 0;
+                       spin_unlock(&req->rq_export->exp_lock);
+               }
+       } else {
+               spin_unlock(&obd->obd_recovery_task_lock);
+       }
+       return req;
 }
 
-static int handle_recovery_req(struct ptlrpc_thread *thread,
-                               struct ptlrpc_request *req,
-                               svc_handler_t handler)
+static void handle_recovery_req(struct ptlrpc_thread *thread,
+                               struct ptlrpc_request *req,
+                               svc_handler_t handler)
 {
-        int rc;
-        ENTRY;
-
-        /**
-         * export can be evicted during recovery, no need to handle replays for
-         * it after that, discard such request silently
-         */
-        if (req->rq_export->exp_disconnected)
-                GOTO(reqcopy_put, rc = 0);
+       ENTRY;
 
-        rc = lu_context_init(&req->rq_recov_session, LCT_SESSION);
-        if (rc) {
-                CERROR("Failure to initialize session: %d\n", rc);
-                GOTO(reqcopy_put, rc);
-        }
+       /**
+        * export can be evicted during recovery, no need to handle replays for
+        * it after that, discard such request silently
+        */
+       if (req->rq_export->exp_disconnected)
+               RETURN_EXIT;
 
-        req->rq_recov_session.lc_thread = thread;
-        lu_context_enter(&req->rq_recov_session);
-        req->rq_svc_thread = thread;
-        req->rq_svc_thread->t_env->le_ses = &req->rq_recov_session;
+       req->rq_session.lc_thread = thread;
+       req->rq_svc_thread = thread;
+       req->rq_svc_thread->t_env->le_ses = &req->rq_session;
 
         /* thread context */
         lu_context_enter(&thread->t_env->le_ctx);
         (void)handler(req);
         lu_context_exit(&thread->t_env->le_ctx);
 
-        lu_context_exit(&req->rq_recov_session);
-        lu_context_fini(&req->rq_recov_session);
         /* don't reset timer for final stage */
         if (!exp_finished(req->rq_export)) {
                 int to = obd_timeout;
@@ -1941,13 +1952,327 @@ static int handle_recovery_req(struct ptlrpc_thread *thread,
                        to = max((int)at_est2timeout(
                                 at_get(&svcpt->scp_at_estimate)),
                                 (int)lustre_msg_get_timeout(req->rq_reqmsg));
-                        /* Add net_latency (see ptlrpc_replay_req) */
-                        to += lustre_msg_get_service_time(req->rq_reqmsg);
+                       /* Add 2 net_latency, one for balance rq_deadline
+                        * (see ptl_send_rpc), one for resend the req to server,
+                        * Note: client will pack net_latency in replay req
+                        * (see ptlrpc_replay_req) */
+                       to += 2 * lustre_msg_get_service_time(req->rq_reqmsg);
                 }
                 extend_recovery_timer(class_exp2obd(req->rq_export), to, true);
         }
-reqcopy_put:
-        RETURN(rc);
+       EXIT;
+}
+
+/** Checking routines for recovery */
+static int check_for_recovery_ready(struct lu_target *lut)
+{
+       struct obd_device *obd = lut->lut_obd;
+       unsigned int clnts = atomic_read(&obd->obd_connected_clients);
+
+       CDEBUG(D_HA, "connected %d stale %d max_recoverable_clients %d"
+              " abort %d expired %d\n", clnts, obd->obd_stale_clients,
+              obd->obd_max_recoverable_clients, obd->obd_abort_recovery,
+              obd->obd_recovery_expired);
+
+       if (obd->obd_force_abort_recovery)
+               return 1;
+
+       if (!obd->obd_abort_recovery && !obd->obd_recovery_expired) {
+               LASSERT(clnts <= obd->obd_max_recoverable_clients);
+               if (clnts + obd->obd_stale_clients <
+                   obd->obd_max_recoverable_clients)
+                       return 0;
+       }
+
+       if (lut->lut_tdtd != NULL) {
+               if (!lut->lut_tdtd->tdtd_replay_ready) {
+                       /* Let's extend recovery timer, in case the recovery
+                        * timer expired, and some clients got evicted */
+                       extend_recovery_timer(obd, obd->obd_recovery_timeout,
+                                             true);
+                       return 0;
+               } else {
+                       dtrq_list_dump(lut->lut_tdtd, D_HA);
+               }
+       }
+
+       return 1;
+}
+
+enum {
+       REQUEST_RECOVERY = 1,
+       UPDATE_RECOVERY = 2,
+};
+
+static __u64 get_next_replay_req_transno(struct obd_device *obd)
+{
+       __u64 transno = 0;
+
+       if (!list_empty(&obd->obd_req_replay_queue)) {
+               struct ptlrpc_request *req;
+
+               req = list_entry(obd->obd_req_replay_queue.next,
+                                struct ptlrpc_request, rq_list);
+               transno = lustre_msg_get_transno(req->rq_reqmsg);
+       }
+
+       return transno;
+}
+__u64 get_next_transno(struct lu_target *lut, int *type)
+{
+       struct obd_device *obd = lut->lut_obd;
+       struct target_distribute_txn_data *tdtd = lut->lut_tdtd;
+       __u64 transno = 0;
+       __u64 update_transno;
+       ENTRY;
+
+       transno = get_next_replay_req_transno(obd);
+       if (type != NULL)
+               *type = REQUEST_RECOVERY;
+
+       if (tdtd == NULL)
+               RETURN(transno);
+
+       update_transno = distribute_txn_get_next_transno(tdtd);
+       if (transno == 0 || (transno >= update_transno &&
+                            update_transno != 0)) {
+               transno = update_transno;
+               if (type != NULL)
+                       *type = UPDATE_RECOVERY;
+       }
+
+       RETURN(transno);
+}
+
+/**
+ * drop duplicate replay request
+ *
+ * Because the operation has been replayed by update recovery, the request
+ * with the same transno will be dropped and also notify the client to send
+ * next replay request.
+ *
+ * \param[in] env      execution environment
+ * \param[in] obd      failover obd device
+ * \param[in] req      request to be dropped
+ */
+static void drop_duplicate_replay_req(struct lu_env *env,
+                                     struct obd_device *obd,
+                                     struct ptlrpc_request *req)
+{
+       DEBUG_REQ(D_HA, req, "remove t"LPD64" from %s because of duplicate"
+                 " update records are found.\n",
+                 lustre_msg_get_transno(req->rq_reqmsg),
+                 libcfs_nid2str(req->rq_peer.nid));
+
+       /* Right now, only for MDS reint operation update replay and
+        * normal request replay can have the same transno */
+       if (lustre_msg_get_opc(req->rq_reqmsg) == MDS_REINT) {
+               req_capsule_set(&req->rq_pill, &RQF_MDS_REINT);
+               req->rq_status = req_capsule_server_pack(&req->rq_pill);
+               if (likely(req->rq_export))
+                       target_committed_to_req(req);
+               lustre_msg_set_transno(req->rq_repmsg, req->rq_transno);
+               target_send_reply(req, req->rq_status, 0);
+       } else {
+               DEBUG_REQ(D_ERROR, req, "wrong opc" "from %s\n",
+               libcfs_nid2str(req->rq_peer.nid));
+       }
+       target_exp_dequeue_req_replay(req);
+       target_request_copy_put(req);
+       obd->obd_replayed_requests++;
+}
+
+/**
+ * Update last_rcvd of the update
+ *
+ * Because update recovery might update the last_rcvd by updates, i.e.
+ * it will not update the last_rcvd information in memory, so we need
+ * refresh these information in memory after update recovery.
+ *
+ * \param[in] obd      obd_device under recoverying.
+ * \param[in] dtrq     the update replay requests being replayed.
+ */
+static void target_update_lcd(struct lu_env *env, struct lu_target *lut,
+                             struct distribute_txn_replay_req *dtrq)
+{
+       struct obd_device       *obd = lut->lut_obd;
+       struct obd_export       *export;
+       struct tg_export_data   *ted;
+       struct distribute_txn_replay_req_sub    *dtrqs;
+       struct seq_server_site *site;
+       struct update_records   *ur;
+       const struct lu_fid     *fid;
+       struct update_ops       *ops;
+       struct update_params    *params;
+       struct update_op        *op;
+       __u32                   mdt_index;
+       unsigned int            i;
+       struct lsd_client_data  *lcd = NULL;
+
+       /* if Updates has been executed(committed) on the recovery target,
+        * i.e. the updates is not being executed on the target, so we do
+        * not need update it in memory */
+       site = lu_site2seq(obd->obd_lu_dev->ld_site);
+       mdt_index = site->ss_node_id;
+       dtrqs = dtrq_sub_lookup(dtrq, mdt_index);
+       if (dtrqs != NULL)
+               return;
+
+       if (dtrq->dtrq_lur == NULL)
+               return;
+
+       /* Find the update last_rcvd record */
+       fid = lu_object_fid(&lut->lut_last_rcvd->do_lu);
+       ur = &dtrq->dtrq_lur->lur_update_rec;
+       ops = &ur->ur_ops;
+       params = update_records_get_params(ur);
+       for (i = 0, op = &ops->uops_op[0]; i < ur->ur_update_count;
+            i++, op = update_op_next_op(op)) {
+               __u64 pos;
+               __u16 size;
+               void *buf;
+
+               if (!lu_fid_eq(&op->uop_fid, fid))
+                       continue;
+
+               if (op->uop_type != OUT_WRITE)
+                       continue;
+
+               buf = update_params_get_param_buf(params, op->uop_params_off[1],
+                                                 ur->ur_param_count, NULL);
+               if (buf == NULL)
+                       continue;
+
+               pos = le64_to_cpu(*(__u64 *)buf);
+               if (pos == 0)
+                       continue;
+
+               buf = update_params_get_param_buf(params, op->uop_params_off[0],
+                                                 ur->ur_param_count, &size);
+               if (buf == NULL)
+                       continue;
+
+               if (size != sizeof(*lcd))
+                       continue;
+               lcd = buf;
+       }
+
+       if (lcd == NULL || lcd->lcd_uuid[0] == '\0')
+               return;
+
+       /* locate the export then update the exp_target_data if needed */
+       export = cfs_hash_lookup(obd->obd_uuid_hash, lcd->lcd_uuid);
+       if (export == NULL)
+               return;
+
+       ted = &export->exp_target_data;
+       if (lcd->lcd_last_xid > ted->ted_lcd->lcd_last_xid) {
+               CDEBUG(D_HA, "%s update xid from "LPU64" to "LPU64"\n",
+                      lut->lut_obd->obd_name, ted->ted_lcd->lcd_last_xid,
+                      lcd->lcd_last_xid);
+               ted->ted_lcd->lcd_last_xid = lcd->lcd_last_xid;
+               ted->ted_lcd->lcd_last_result = lcd->lcd_last_result;
+       }
+       class_export_put(export);
+}
+
+static void replay_request_or_update(struct lu_env *env,
+                                    struct lu_target *lut,
+                                    struct target_recovery_data *trd,
+                                    struct ptlrpc_thread *thread)
+{
+       struct obd_device *obd = lut->lut_obd;
+       struct ptlrpc_request *req = NULL;
+       int                     type;
+       __u64                   transno;
+       ENTRY;
+
+       CDEBUG(D_HA, "Waiting for transno "LPD64"\n",
+              obd->obd_next_recovery_transno);
+
+       /* Replay all of request and update by transno */
+       do {
+               struct target_distribute_txn_data *tdtd = lut->lut_tdtd;
+
+               CFS_FAIL_TIMEOUT(OBD_FAIL_TGT_REPLAY_DELAY2, cfs_fail_val);
+
+               /** It is needed to extend recovery window above
+                *  recovery_time_soft. Extending is possible only in the
+                *  end of recovery window (see more details in
+                *  handle_recovery_req()).
+                */
+               CFS_FAIL_TIMEOUT_MS(OBD_FAIL_TGT_REPLAY_DELAY, 300);
+
+               if (target_recovery_overseer(lut, check_for_next_transno,
+                                            exp_req_replay_healthy)) {
+                       abort_req_replay_queue(obd);
+                       abort_lock_replay_queue(obd);
+               }
+
+               spin_lock(&obd->obd_recovery_task_lock);
+               transno = get_next_transno(lut, &type);
+               if (type == REQUEST_RECOVERY && tdtd != NULL &&
+                   transno == tdtd->tdtd_last_update_transno) {
+                       /* Drop replay request from client side, if the
+                        * replay has been executed by update with the
+                        * same transno */
+                       req = list_entry(obd->obd_req_replay_queue.next,
+                                       struct ptlrpc_request, rq_list);
+                       list_del_init(&req->rq_list);
+                       obd->obd_requests_queued_for_recovery--;
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       drop_duplicate_replay_req(env, obd, req);
+               } else if (type == REQUEST_RECOVERY && transno != 0) {
+                       req = list_entry(obd->obd_req_replay_queue.next,
+                                            struct ptlrpc_request, rq_list);
+                       list_del_init(&req->rq_list);
+                       obd->obd_requests_queued_for_recovery--;
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       LASSERT(trd->trd_processing_task == current_pid());
+                       DEBUG_REQ(D_HA, req, "processing t"LPD64" from %s",
+                                 lustre_msg_get_transno(req->rq_reqmsg),
+                                 libcfs_nid2str(req->rq_peer.nid));
+
+                       handle_recovery_req(thread, req,
+                                           trd->trd_recovery_handler);
+                       /**
+                        * bz18031: increase next_recovery_transno before
+                        * target_request_copy_put() will drop exp_rpc reference
+                        */
+                       spin_lock(&obd->obd_recovery_task_lock);
+                       obd->obd_next_recovery_transno++;
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       target_exp_dequeue_req_replay(req);
+                       target_request_copy_put(req);
+                       obd->obd_replayed_requests++;
+               } else if (type == UPDATE_RECOVERY && transno != 0) {
+                       struct distribute_txn_replay_req *dtrq;
+
+                       spin_unlock(&obd->obd_recovery_task_lock);
+
+                       LASSERT(tdtd != NULL);
+                       dtrq = distribute_txn_get_next_req(tdtd);
+                       lu_context_enter(&thread->t_env->le_ctx);
+                       tdtd->tdtd_replay_handler(env, tdtd, dtrq);
+                       lu_context_exit(&thread->t_env->le_ctx);
+                       extend_recovery_timer(obd, obd_timeout, true);
+                       LASSERT(tdtd->tdtd_last_update_transno <= transno);
+                       tdtd->tdtd_last_update_transno = transno;
+                       spin_lock(&obd->obd_recovery_task_lock);
+                       if (transno > obd->obd_next_recovery_transno)
+                               obd->obd_next_recovery_transno = transno;
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       target_update_lcd(env, lut, dtrq);
+                       dtrq_destory(dtrq);
+               } else {
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       LASSERT(list_empty(&obd->obd_req_replay_queue));
+                       LASSERT(atomic_read(&obd->obd_req_replay_clients) == 0);
+                       /** evict exports failed VBR */
+                       class_disconnect_stale_exports(obd, exp_vbr_healthy);
+                       break;
+               }
+       } while (1);
 }
 
 static int target_recovery_thread(void *arg)
@@ -1957,19 +2282,12 @@ static int target_recovery_thread(void *arg)
         struct ptlrpc_request *req;
         struct target_recovery_data *trd = &obd->obd_recovery_data;
         unsigned long delta;
-        unsigned long flags;
         struct lu_env *env;
         struct ptlrpc_thread *thread = NULL;
         int rc = 0;
         ENTRY;
 
-        cfs_daemonize_ctxt("tgt_recov");
-
-        SIGNAL_MASK_LOCK(current, flags);
-        sigfillset(&current->blocked);
-        RECALC_SIGPENDING;
-        SIGNAL_MASK_UNLOCK(current, flags);
-
+       unshare_fs_struct();
         OBD_ALLOC_PTR(thread);
         if (thread == NULL)
                 RETURN(-ENOMEM);
@@ -1990,143 +2308,137 @@ static int target_recovery_thread(void *arg)
         thread->t_env = env;
         thread->t_id = -1; /* force filter_iobuf_get/put to use local buffers */
         env->le_ctx.lc_thread = thread;
-        thread->t_data = NULL;
-        thread->t_watchdog = NULL;
-
-        CDEBUG(D_HA, "%s: started recovery thread pid %d\n", obd->obd_name,
-               cfs_curproc_pid());
-        trd->trd_processing_task = cfs_curproc_pid();
-
-        cfs_spin_lock(&obd->obd_dev_lock);
-        obd->obd_recovering = 1;
-        cfs_spin_unlock(&obd->obd_dev_lock);
-        cfs_complete(&trd->trd_starting);
-
-        /* first of all, we have to know the first transno to replay */
-        if (target_recovery_overseer(obd, check_for_clients,
-                                     exp_connect_healthy)) {
-                abort_req_replay_queue(obd);
-                abort_lock_replay_queue(obd);
-        }
+       tgt_io_thread_init(thread); /* init thread_big_cache for IO requests */
+       thread->t_watchdog = NULL;
+
+       CDEBUG(D_HA, "%s: started recovery thread pid %d\n", obd->obd_name,
+              current_pid());
+       trd->trd_processing_task = current_pid();
+
+       spin_lock(&obd->obd_dev_lock);
+       obd->obd_recovering = 1;
+       spin_unlock(&obd->obd_dev_lock);
+       complete(&trd->trd_starting);
+
+       /* first of all, we have to know the first transno to replay */
+       if (target_recovery_overseer(lut, check_for_recovery_ready,
+                                    exp_connect_healthy)) {
+               abort_req_replay_queue(obd);
+               abort_lock_replay_queue(obd);
+               if (lut->lut_tdtd != NULL)
+                       dtrq_list_destroy(lut->lut_tdtd);
+       }
 
-        /* next stage: replay requests */
-        delta = jiffies;
-        CDEBUG(D_INFO, "1: request replay stage - %d clients from t"LPU64"\n",
-               cfs_atomic_read(&obd->obd_req_replay_clients),
-               obd->obd_next_recovery_transno);
-        while ((req = target_next_replay_req(obd))) {
-                LASSERT(trd->trd_processing_task == cfs_curproc_pid());
-                DEBUG_REQ(D_HA, req, "processing t"LPD64" from %s",
-                          lustre_msg_get_transno(req->rq_reqmsg),
-                          libcfs_nid2str(req->rq_peer.nid));
-                handle_recovery_req(thread, req,
-                                    trd->trd_recovery_handler);
-                /**
-                 * bz18031: increase next_recovery_transno before
-                 * target_request_copy_put() will drop exp_rpc reference
-                 */
-                cfs_spin_lock(&obd->obd_recovery_task_lock);
-                obd->obd_next_recovery_transno++;
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                target_exp_dequeue_req_replay(req);
-                target_request_copy_put(req);
-                obd->obd_replayed_requests++;
-        }
+       /* next stage: replay requests or update */
+       delta = jiffies;
+       CDEBUG(D_INFO, "1: request replay stage - %d clients from t"LPU64"\n",
+              atomic_read(&obd->obd_req_replay_clients),
+              obd->obd_next_recovery_transno);
+       replay_request_or_update(env, lut, trd, thread);
 
-        /**
-         * The second stage: replay locks
-         */
-        CDEBUG(D_INFO, "2: lock replay stage - %d clients\n",
-               cfs_atomic_read(&obd->obd_lock_replay_clients));
-        while ((req = target_next_replay_lock(obd))) {
-                LASSERT(trd->trd_processing_task == cfs_curproc_pid());
-                DEBUG_REQ(D_HA, req, "processing lock from %s: ",
-                          libcfs_nid2str(req->rq_peer.nid));
-                handle_recovery_req(thread, req,
-                                    trd->trd_recovery_handler);
-                target_request_copy_put(req);
-                obd->obd_replayed_locks++;
-        }
+       /**
+        * The second stage: replay locks
+        */
+       CDEBUG(D_INFO, "2: lock replay stage - %d clients\n",
+              atomic_read(&obd->obd_lock_replay_clients));
+       while ((req = target_next_replay_lock(lut))) {
+               LASSERT(trd->trd_processing_task == current_pid());
+               DEBUG_REQ(D_HA, req, "processing lock from %s: ",
+                         libcfs_nid2str(req->rq_peer.nid));
+               handle_recovery_req(thread, req,
+                                   trd->trd_recovery_handler);
+               target_request_copy_put(req);
+               obd->obd_replayed_locks++;
+       }
 
         /**
          * The third stage: reply on final pings, at this moment all clients
          * must have request in final queue
          */
+       CFS_FAIL_TIMEOUT(OBD_FAIL_TGT_REPLAY_RECONNECT, cfs_fail_val);
         CDEBUG(D_INFO, "3: final stage - process recovery completion pings\n");
         /** Update server last boot epoch */
-        lut_boot_epoch_update(lut);
+        tgt_boot_epoch_update(lut);
         /* We drop recoverying flag to forward all new requests
          * to regular mds_handle() since now */
-        cfs_spin_lock(&obd->obd_dev_lock);
-        obd->obd_recovering = obd->obd_abort_recovery = 0;
-        cfs_spin_unlock(&obd->obd_dev_lock);
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        target_cancel_recovery_timer(obd);
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        while ((req = target_next_final_ping(obd))) {
-                LASSERT(trd->trd_processing_task == cfs_curproc_pid());
-                DEBUG_REQ(D_HA, req, "processing final ping from %s: ",
-                          libcfs_nid2str(req->rq_peer.nid));
+       spin_lock(&obd->obd_dev_lock);
+       obd->obd_recovering = obd->obd_abort_recovery = 0;
+       spin_unlock(&obd->obd_dev_lock);
+       spin_lock(&obd->obd_recovery_task_lock);
+       target_cancel_recovery_timer(obd);
+       spin_unlock(&obd->obd_recovery_task_lock);
+       while ((req = target_next_final_ping(obd))) {
+               LASSERT(trd->trd_processing_task == current_pid());
+               DEBUG_REQ(D_HA, req, "processing final ping from %s: ",
+                         libcfs_nid2str(req->rq_peer.nid));
                 handle_recovery_req(thread, req,
                                     trd->trd_recovery_handler);
-                target_request_copy_put(req);
-        }
+               /* Because the waiting client can not send ping to server,
+                * so we need refresh the last_request_time, to avoid the
+                * export is being evicted */
+               ptlrpc_update_export_timer(req->rq_export, 0);
+               target_request_copy_put(req);
+       }
 
-        delta = (jiffies - delta) / CFS_HZ;
-        CDEBUG(D_INFO,"4: recovery completed in %lus - %d/%d reqs/locks\n",
-              delta, obd->obd_replayed_requests, obd->obd_replayed_locks);
-        if (delta > OBD_RECOVERY_TIME_SOFT) {
-                CWARN("too long recovery - read logs\n");
-                libcfs_debug_dumplog();
-        }
+       delta = jiffies_to_msecs(jiffies - delta) / MSEC_PER_SEC;
+       CDEBUG(D_INFO,"4: recovery completed in %lus - %d/%d reqs/locks\n",
+             delta, obd->obd_replayed_requests, obd->obd_replayed_locks);
+       if (delta > OBD_RECOVERY_TIME_SOFT) {
+               CWARN("too long recovery - read logs\n");
+               libcfs_debug_dumplog();
+       }
 
-        target_finish_recovery(obd);
+       target_finish_recovery(lut);
 
         lu_context_fini(&env->le_ctx);
         trd->trd_processing_task = 0;
-        cfs_complete(&trd->trd_finishing);
+       complete(&trd->trd_finishing);
 
-        OBD_FREE_PTR(thread);
-        OBD_FREE_PTR(env);
-        RETURN(rc);
+       tgt_io_thread_done(thread);
+       OBD_FREE_PTR(thread);
+       OBD_FREE_PTR(env);
+       RETURN(rc);
 }
 
 static int target_start_recovery_thread(struct lu_target *lut,
                                         svc_handler_t handler)
 {
-        struct obd_device *obd = lut->lut_obd;
-        int rc = 0;
-        struct target_recovery_data *trd = &obd->obd_recovery_data;
-
-        memset(trd, 0, sizeof(*trd));
-        cfs_init_completion(&trd->trd_starting);
-        cfs_init_completion(&trd->trd_finishing);
-        trd->trd_recovery_handler = handler;
-
-        if (cfs_create_thread(target_recovery_thread, lut, 0) > 0) {
-                cfs_wait_for_completion(&trd->trd_starting);
-                LASSERT(obd->obd_recovering != 0);
-        } else
-                rc = -ECHILD;
+       struct obd_device *obd = lut->lut_obd;
+       int rc = 0;
+       struct target_recovery_data *trd = &obd->obd_recovery_data;
+
+       memset(trd, 0, sizeof(*trd));
+       init_completion(&trd->trd_starting);
+       init_completion(&trd->trd_finishing);
+       trd->trd_recovery_handler = handler;
+
+       if (!IS_ERR(kthread_run(target_recovery_thread,
+                               lut, "tgt_recov"))) {
+               wait_for_completion(&trd->trd_starting);
+               LASSERT(obd->obd_recovering != 0);
+       } else {
+               rc = -ECHILD;
+       }
 
-        return rc;
+       return rc;
 }
 
 void target_stop_recovery_thread(struct obd_device *obd)
 {
-        if (obd->obd_recovery_data.trd_processing_task > 0) {
-                struct target_recovery_data *trd = &obd->obd_recovery_data;
-                /** recovery can be done but postrecovery is not yet */
-                cfs_spin_lock(&obd->obd_dev_lock);
-                if (obd->obd_recovering) {
-                        CERROR("%s: Aborting recovery\n", obd->obd_name);
-                        obd->obd_abort_recovery = 1;
-                        cfs_waitq_signal(&obd->obd_next_transno_waitq);
-                }
-                cfs_spin_unlock(&obd->obd_dev_lock);
-                cfs_wait_for_completion(&trd->trd_finishing);
-        }
+       if (obd->obd_recovery_data.trd_processing_task > 0) {
+               struct target_recovery_data *trd = &obd->obd_recovery_data;
+               /** recovery can be done but postrecovery is not yet */
+               spin_lock(&obd->obd_dev_lock);
+               if (obd->obd_recovering) {
+                       CERROR("%s: Aborting recovery\n", obd->obd_name);
+                       obd->obd_abort_recovery = 1;
+                       wake_up(&obd->obd_next_transno_waitq);
+               }
+               spin_unlock(&obd->obd_dev_lock);
+               wait_for_completion(&trd->trd_finishing);
+       }
 }
+EXPORT_SYMBOL(target_stop_recovery_thread);
 
 void target_recovery_fini(struct obd_device *obd)
 {
@@ -2138,29 +2450,30 @@ EXPORT_SYMBOL(target_recovery_fini);
 
 static void target_recovery_expired(unsigned long castmeharder)
 {
-        struct obd_device *obd = (struct obd_device *)castmeharder;
-        CDEBUG(D_HA, "%s: recovery timed out; %d clients are still in recovery"
-               " after %lds (%d clients connected)\n",
-               obd->obd_name, cfs_atomic_read(&obd->obd_lock_replay_clients),
-               cfs_time_current_sec()- obd->obd_recovery_start,
-               cfs_atomic_read(&obd->obd_connected_clients));
-
-        obd->obd_recovery_expired = 1;
-        cfs_waitq_signal(&obd->obd_next_transno_waitq);
+       struct obd_device *obd = (struct obd_device *)castmeharder;
+       CDEBUG(D_HA, "%s: recovery timed out; %d clients are still in recovery"
+              " after %lds (%d clients connected)\n",
+              obd->obd_name, atomic_read(&obd->obd_lock_replay_clients),
+              cfs_time_current_sec()- obd->obd_recovery_start,
+              atomic_read(&obd->obd_connected_clients));
+
+       obd->obd_recovery_expired = 1;
+       wake_up(&obd->obd_next_transno_waitq);
 }
 
 void target_recovery_init(struct lu_target *lut, svc_handler_t handler)
 {
         struct obd_device *obd = lut->lut_obd;
+
         if (obd->obd_max_recoverable_clients == 0) {
                 /** Update server last boot epoch */
-                lut_boot_epoch_update(lut);
+                tgt_boot_epoch_update(lut);
                 return;
         }
 
-        CWARN("RECOVERY: service %s, %d recoverable clients, "
-              "last_transno "LPU64"\n", obd->obd_name,
-              obd->obd_max_recoverable_clients, obd->obd_last_committed);
+       CDEBUG(D_HA, "RECOVERY: service %s, %d recoverable clients, "
+              "last_transno "LPU64"\n", obd->obd_name,
+              obd->obd_max_recoverable_clients, obd->obd_last_committed);
         LASSERT(obd->obd_stopping == 0);
         obd->obd_next_recovery_transno = obd->obd_last_committed + 1;
         obd->obd_recovery_start = 0;
@@ -2171,101 +2484,99 @@ void target_recovery_init(struct lu_target *lut, svc_handler_t handler)
 }
 EXPORT_SYMBOL(target_recovery_init);
 
-#endif /* __KERNEL__ */
-
 static int target_process_req_flags(struct obd_device *obd,
                                     struct ptlrpc_request *req)
 {
-        struct obd_export *exp = req->rq_export;
-        LASSERT(exp != NULL);
-        if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_REQ_REPLAY_DONE) {
-                /* client declares he's ready to replay locks */
-                cfs_spin_lock(&exp->exp_lock);
-                if (exp->exp_req_replay_needed) {
-                        exp->exp_req_replay_needed = 0;
-                        cfs_spin_unlock(&exp->exp_lock);
-
-                        LASSERT_ATOMIC_POS(&obd->obd_req_replay_clients);
-                        cfs_atomic_dec(&obd->obd_req_replay_clients);
-                } else {
-                        cfs_spin_unlock(&exp->exp_lock);
-                }
-        }
-        if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_LOCK_REPLAY_DONE) {
-                /* client declares he's ready to complete recovery
-                 * so, we put the request on th final queue */
-                cfs_spin_lock(&exp->exp_lock);
-                if (exp->exp_lock_replay_needed) {
-                        exp->exp_lock_replay_needed = 0;
-                        cfs_spin_unlock(&exp->exp_lock);
-
-                        LASSERT_ATOMIC_POS(&obd->obd_lock_replay_clients);
-                        cfs_atomic_dec(&obd->obd_lock_replay_clients);
-                } else {
-                        cfs_spin_unlock(&exp->exp_lock);
-                }
-        }
-        return 0;
+       struct obd_export *exp = req->rq_export;
+       LASSERT(exp != NULL);
+       if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_REQ_REPLAY_DONE) {
+               /* client declares he's ready to replay locks */
+               spin_lock(&exp->exp_lock);
+               if (exp->exp_req_replay_needed) {
+                       exp->exp_req_replay_needed = 0;
+                       spin_unlock(&exp->exp_lock);
+
+                       LASSERT_ATOMIC_POS(&obd->obd_req_replay_clients);
+                       atomic_dec(&obd->obd_req_replay_clients);
+               } else {
+                       spin_unlock(&exp->exp_lock);
+               }
+       }
+       if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_LOCK_REPLAY_DONE) {
+               /* client declares he's ready to complete recovery
+                * so, we put the request on th final queue */
+               spin_lock(&exp->exp_lock);
+               if (exp->exp_lock_replay_needed) {
+                       exp->exp_lock_replay_needed = 0;
+                       spin_unlock(&exp->exp_lock);
+
+                       LASSERT_ATOMIC_POS(&obd->obd_lock_replay_clients);
+                       atomic_dec(&obd->obd_lock_replay_clients);
+               } else {
+                       spin_unlock(&exp->exp_lock);
+               }
+       }
+       return 0;
 }
 
 int target_queue_recovery_request(struct ptlrpc_request *req,
                                   struct obd_device *obd)
 {
-        cfs_list_t *tmp;
-        int inserted = 0;
         __u64 transno = lustre_msg_get_transno(req->rq_reqmsg);
-        ENTRY;
+       struct ptlrpc_request *reqiter;
+       int inserted = 0;
+       ENTRY;
 
-        if (obd->obd_recovery_data.trd_processing_task == cfs_curproc_pid()) {
-                /* Processing the queue right now, don't re-add. */
-                RETURN(1);
-        }
+       if (obd->obd_recovery_data.trd_processing_task == current_pid()) {
+               /* Processing the queue right now, don't re-add. */
+               RETURN(1);
+       }
 
         target_process_req_flags(obd, req);
 
         if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_LOCK_REPLAY_DONE) {
                 /* client declares he's ready to complete recovery
                  * so, we put the request on th final queue */
-                target_request_copy_get(req);
-                DEBUG_REQ(D_HA, req, "queue final req");
-                cfs_waitq_signal(&obd->obd_next_transno_waitq);
-                cfs_spin_lock(&obd->obd_recovery_task_lock);
-                if (obd->obd_recovering) {
-                        cfs_list_add_tail(&req->rq_list,
-                                          &obd->obd_final_req_queue);
-                } else {
-                        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                        target_request_copy_put(req);
-                        RETURN(obd->obd_stopping ? -ENOTCONN : 1);
-                }
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                RETURN(0);
-        }
-        if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_REQ_REPLAY_DONE) {
-                /* client declares he's ready to replay locks */
-                target_request_copy_get(req);
-                DEBUG_REQ(D_HA, req, "queue lock replay req");
-                cfs_waitq_signal(&obd->obd_next_transno_waitq);
-                cfs_spin_lock(&obd->obd_recovery_task_lock);
-                LASSERT(obd->obd_recovering);
-                /* usually due to recovery abort */
-                if (!req->rq_export->exp_in_recovery) {
-                        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                        target_request_copy_put(req);
-                        RETURN(-ENOTCONN);
-                }
-                LASSERT(req->rq_export->exp_lock_replay_needed);
-                cfs_list_add_tail(&req->rq_list, &obd->obd_lock_replay_queue);
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                RETURN(0);
-        }
+               target_request_copy_get(req);
+               DEBUG_REQ(D_HA, req, "queue final req");
+               wake_up(&obd->obd_next_transno_waitq);
+               spin_lock(&obd->obd_recovery_task_lock);
+               if (obd->obd_recovering) {
+                       list_add_tail(&req->rq_list,
+                                         &obd->obd_final_req_queue);
+               } else {
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       target_request_copy_put(req);
+                       RETURN(obd->obd_stopping ? -ENOTCONN : 1);
+               }
+               spin_unlock(&obd->obd_recovery_task_lock);
+               RETURN(0);
+       }
+       if (lustre_msg_get_flags(req->rq_reqmsg) & MSG_REQ_REPLAY_DONE) {
+               /* client declares he's ready to replay locks */
+               target_request_copy_get(req);
+               DEBUG_REQ(D_HA, req, "queue lock replay req");
+               wake_up(&obd->obd_next_transno_waitq);
+               spin_lock(&obd->obd_recovery_task_lock);
+               LASSERT(obd->obd_recovering);
+               /* usually due to recovery abort */
+               if (!req->rq_export->exp_in_recovery) {
+                       spin_unlock(&obd->obd_recovery_task_lock);
+                       target_request_copy_put(req);
+                       RETURN(-ENOTCONN);
+               }
+               LASSERT(req->rq_export->exp_lock_replay_needed);
+               list_add_tail(&req->rq_list, &obd->obd_lock_replay_queue);
+               spin_unlock(&obd->obd_recovery_task_lock);
+               RETURN(0);
+       }
 
         /* CAVEAT EMPTOR: The incoming request message has been swabbed
          * (i.e. buflens etc are in my own byte order), but type-dependent
          * buffers (eg mdt_body, ost_body etc) have NOT been swabbed. */
 
         if (!transno) {
-                CFS_INIT_LIST_HEAD(&req->rq_list);
+               INIT_LIST_HEAD(&req->rq_list);
                 DEBUG_REQ(D_HA, req, "not queueing");
                 RETURN(1);
         }
@@ -2283,14 +2594,14 @@ int target_queue_recovery_request(struct ptlrpc_request *req,
         CDEBUG(D_HA, "Next recovery transno: "LPU64
                ", current: "LPU64", replaying\n",
                obd->obd_next_recovery_transno, transno);
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (transno < obd->obd_next_recovery_transno) {
-                /* Processing the queue right now, don't re-add. */
-                LASSERT(cfs_list_empty(&req->rq_list));
-                cfs_spin_unlock(&obd->obd_recovery_task_lock);
-                RETURN(1);
-        }
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
+       spin_lock(&obd->obd_recovery_task_lock);
+       if (transno < obd->obd_next_recovery_transno) {
+               /* Processing the queue right now, don't re-add. */
+               LASSERT(list_empty(&req->rq_list));
+               spin_unlock(&obd->obd_recovery_task_lock);
+               RETURN(1);
+       }
+       spin_unlock(&obd->obd_recovery_task_lock);
 
         if (OBD_FAIL_CHECK(OBD_FAIL_TGT_REPLAY_DROP))
                 RETURN(0);
@@ -2308,37 +2619,34 @@ int target_queue_recovery_request(struct ptlrpc_request *req,
                 RETURN(0);
         }
 
-        /* XXX O(n^2) */
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        LASSERT(obd->obd_recovering);
-        cfs_list_for_each(tmp, &obd->obd_req_replay_queue) {
-                struct ptlrpc_request *reqiter =
-                        cfs_list_entry(tmp, struct ptlrpc_request, rq_list);
-
-                if (lustre_msg_get_transno(reqiter->rq_reqmsg) > transno) {
-                        cfs_list_add_tail(&req->rq_list, &reqiter->rq_list);
-                        inserted = 1;
-                        break;
-                }
+       /* XXX O(n^2) */
+       spin_lock(&obd->obd_recovery_task_lock);
+       LASSERT(obd->obd_recovering);
+       list_for_each_entry(reqiter, &obd->obd_req_replay_queue, rq_list) {
+               if (lustre_msg_get_transno(reqiter->rq_reqmsg) > transno) {
+                       list_add_tail(&req->rq_list, &reqiter->rq_list);
+                       inserted = 1;
+                       goto added;
+               }
 
                 if (unlikely(lustre_msg_get_transno(reqiter->rq_reqmsg) ==
                              transno)) {
                         DEBUG_REQ(D_ERROR, req, "dropping replay: transno "
                                   "has been claimed by another client");
-                        cfs_spin_unlock(&obd->obd_recovery_task_lock);
+                       spin_unlock(&obd->obd_recovery_task_lock);
                         target_exp_dequeue_req_replay(req);
                         target_request_copy_put(req);
                         RETURN(0);
                 }
         }
-
+added:
         if (!inserted)
-                cfs_list_add_tail(&req->rq_list, &obd->obd_req_replay_queue);
+               list_add_tail(&req->rq_list, &obd->obd_req_replay_queue);
 
         obd->obd_requests_queued_for_recovery++;
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        cfs_waitq_signal(&obd->obd_next_transno_waitq);
-        RETURN(0);
+       spin_unlock(&obd->obd_recovery_task_lock);
+       wake_up(&obd->obd_next_transno_waitq);
+       RETURN(0);
 }
 
 int target_handle_ping(struct ptlrpc_request *req)
@@ -2362,7 +2670,6 @@ void target_committed_to_req(struct ptlrpc_request *req)
         CDEBUG(D_INFO, "last_committed "LPU64", transno "LPU64", xid "LPU64"\n",
                exp->exp_last_committed, req->rq_transno, req->rq_xid);
 }
-EXPORT_SYMBOL(target_committed_to_req);
 
 #endif /* HAVE_SERVER_SUPPORT */
 
@@ -2374,10 +2681,8 @@ int target_pack_pool_reply(struct ptlrpc_request *req)
         struct obd_device *obd;
         ENTRY;
 
-        /*
-         * Check that we still have all structures alive as this may
-         * be some late rpc in shutdown time.
-         */
+       /* Check that we still have all structures alive as this may
+        * be some late RPC at shutdown time. */
         if (unlikely(!req->rq_export || !req->rq_export->exp_obd ||
                      !exp_connect_lru_resize(req->rq_export))) {
                 lustre_msg_set_slv(req->rq_repmsg, 0);
@@ -2385,20 +2690,19 @@ int target_pack_pool_reply(struct ptlrpc_request *req)
                 RETURN(0);
         }
 
-        /*
-         * OBD is alive here as export is alive, which we checked above.
-         */
+       /* OBD is alive here as export is alive, which we checked above. */
         obd = req->rq_export->exp_obd;
 
-        cfs_read_lock(&obd->obd_pool_lock);
+       read_lock(&obd->obd_pool_lock);
         lustre_msg_set_slv(req->rq_repmsg, obd->obd_pool_slv);
         lustre_msg_set_limit(req->rq_repmsg, obd->obd_pool_limit);
-        cfs_read_unlock(&obd->obd_pool_lock);
+       read_unlock(&obd->obd_pool_lock);
 
         RETURN(0);
 }
 
-int target_send_reply_msg(struct ptlrpc_request *req, int rc, int fail_id)
+static int target_send_reply_msg(struct ptlrpc_request *req,
+                                int rc, int fail_id)
 {
         if (OBD_FAIL_CHECK_ORSET(fail_id & ~OBD_FAIL_ONCE, OBD_FAIL_ONCE)) {
                 DEBUG_REQ(D_ERROR, req, "dropping reply");
@@ -2439,20 +2743,20 @@ void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id)
         }
 
         /* must be an export if locks saved */
-        LASSERT (req->rq_export != NULL);
+       LASSERT(req->rq_export != NULL);
         /* req/reply consistent */
        LASSERT(rs->rs_svcpt == svcpt);
 
         /* "fresh" reply */
-        LASSERT (!rs->rs_scheduled);
-        LASSERT (!rs->rs_scheduled_ever);
-        LASSERT (!rs->rs_handled);
-        LASSERT (!rs->rs_on_net);
-        LASSERT (rs->rs_export == NULL);
-        LASSERT (cfs_list_empty(&rs->rs_obd_list));
-        LASSERT (cfs_list_empty(&rs->rs_exp_list));
+       LASSERT(!rs->rs_scheduled);
+       LASSERT(!rs->rs_scheduled_ever);
+       LASSERT(!rs->rs_handled);
+       LASSERT(!rs->rs_on_net);
+       LASSERT(rs->rs_export == NULL);
+       LASSERT(list_empty(&rs->rs_obd_list));
+       LASSERT(list_empty(&rs->rs_exp_list));
 
-        exp = class_export_get (req->rq_export);
+       exp = class_export_get(req->rq_export);
 
         /* disable reply scheduling while I'm setting up */
         rs->rs_scheduled = 1;
@@ -2462,61 +2766,61 @@ void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id)
         rs->rs_export    = exp;
         rs->rs_opc       = lustre_msg_get_opc(req->rq_reqmsg);
 
-        cfs_spin_lock(&exp->exp_uncommitted_replies_lock);
-        CDEBUG(D_NET, "rs transno = "LPU64", last committed = "LPU64"\n",
-               rs->rs_transno, exp->exp_last_committed);
-        if (rs->rs_transno > exp->exp_last_committed) {
-                /* not committed already */
-                cfs_list_add_tail(&rs->rs_obd_list,
-                                  &exp->exp_uncommitted_replies);
-        }
-        cfs_spin_unlock (&exp->exp_uncommitted_replies_lock);
+       spin_lock(&exp->exp_uncommitted_replies_lock);
+       CDEBUG(D_NET, "rs transno = "LPU64", last committed = "LPU64"\n",
+              rs->rs_transno, exp->exp_last_committed);
+       if (rs->rs_transno > exp->exp_last_committed) {
+               /* not committed already */
+               list_add_tail(&rs->rs_obd_list,
+                                 &exp->exp_uncommitted_replies);
+       }
+       spin_unlock(&exp->exp_uncommitted_replies_lock);
 
-        cfs_spin_lock(&exp->exp_lock);
-        cfs_list_add_tail(&rs->rs_exp_list, &exp->exp_outstanding_replies);
-        cfs_spin_unlock(&exp->exp_lock);
+       spin_lock(&exp->exp_lock);
+       list_add_tail(&rs->rs_exp_list, &exp->exp_outstanding_replies);
+       spin_unlock(&exp->exp_lock);
 
-        netrc = target_send_reply_msg (req, rc, fail_id);
+       netrc = target_send_reply_msg(req, rc, fail_id);
 
-       cfs_spin_lock(&svcpt->scp_rep_lock);
+       spin_lock(&svcpt->scp_rep_lock);
 
-       cfs_atomic_inc(&svcpt->scp_nreps_difficult);
+       atomic_inc(&svcpt->scp_nreps_difficult);
 
-        if (netrc != 0) {
-                /* error sending: reply is off the net.  Also we need +1
-                 * reply ref until ptlrpc_handle_rs() is done
-                 * with the reply state (if the send was successful, there
-                 * would have been +1 ref for the net, which
-                 * reply_out_callback leaves alone) */
-                rs->rs_on_net = 0;
-                ptlrpc_rs_addref(rs);
-        }
+       if (netrc != 0) {
+               /* error sending: reply is off the net.  Also we need +1
+                * reply ref until ptlrpc_handle_rs() is done
+                * with the reply state (if the send was successful, there
+                * would have been +1 ref for the net, which
+                * reply_out_callback leaves alone) */
+               rs->rs_on_net = 0;
+               ptlrpc_rs_addref(rs);
+       }
 
-        cfs_spin_lock(&rs->rs_lock);
-        if (rs->rs_transno <= exp->exp_last_committed ||
-            (!rs->rs_on_net && !rs->rs_no_ack) ||
-             cfs_list_empty(&rs->rs_exp_list) ||     /* completed already */
-             cfs_list_empty(&rs->rs_obd_list)) {
-                CDEBUG(D_HA, "Schedule reply immediately\n");
-                ptlrpc_dispatch_difficult_reply(rs);
-        } else {
-               cfs_list_add(&rs->rs_list, &svcpt->scp_rep_active);
+       spin_lock(&rs->rs_lock);
+       if (rs->rs_transno <= exp->exp_last_committed ||
+           (!rs->rs_on_net && !rs->rs_no_ack) ||
+           list_empty(&rs->rs_exp_list) ||     /* completed already */
+           list_empty(&rs->rs_obd_list)) {
+               CDEBUG(D_HA, "Schedule reply immediately\n");
+               ptlrpc_dispatch_difficult_reply(rs);
+       } else {
+               list_add(&rs->rs_list, &svcpt->scp_rep_active);
                rs->rs_scheduled = 0;   /* allow notifier to schedule */
        }
-       cfs_spin_unlock(&rs->rs_lock);
-       cfs_spin_unlock(&svcpt->scp_rep_lock);
+       spin_unlock(&rs->rs_lock);
+       spin_unlock(&svcpt->scp_rep_lock);
        EXIT;
 }
 
 ldlm_mode_t lck_compat_array[] = {
-        [LCK_EX] LCK_COMPAT_EX,
-        [LCK_PW] LCK_COMPAT_PW,
-        [LCK_PR] LCK_COMPAT_PR,
-        [LCK_CW] LCK_COMPAT_CW,
-        [LCK_CR] LCK_COMPAT_CR,
-        [LCK_NL] LCK_COMPAT_NL,
-        [LCK_GROUP] LCK_COMPAT_GROUP,
-        [LCK_COS] LCK_COMPAT_COS,
+       [LCK_EX]    = LCK_COMPAT_EX,
+       [LCK_PW]    = LCK_COMPAT_PW,
+       [LCK_PR]    = LCK_COMPAT_PR,
+       [LCK_CW]    = LCK_COMPAT_CW,
+       [LCK_CR]    = LCK_COMPAT_CR,
+       [LCK_NL]    = LCK_COMPAT_NL,
+       [LCK_GROUP] = LCK_COMPAT_GROUP,
+       [LCK_COS]   = LCK_COMPAT_COS,
 };
 
 /**
@@ -2529,6 +2833,7 @@ int ldlm_error2errno(ldlm_error_t error)
 
         switch (error) {
         case ELDLM_OK:
+       case ELDLM_LOCK_MATCHED:
                 result = 0;
                 break;
         case ELDLM_LOCK_CHANGED:
@@ -2595,21 +2900,21 @@ ldlm_error_t ldlm_errno2error(int err_no)
         }
         return error;
 }
-EXPORT_SYMBOL(ldlm_errno2error);
 
 #if LUSTRE_TRACKS_LOCK_EXP_REFS
 void ldlm_dump_export_locks(struct obd_export *exp)
 {
-        cfs_spin_lock(&exp->exp_locks_list_guard);
-        if (!cfs_list_empty(&exp->exp_locks_list)) {
-            struct ldlm_lock *lock;
-
-            CERROR("dumping locks for export %p,"
-                   "ignore if the unmount doesn't hang\n", exp);
-            cfs_list_for_each_entry(lock, &exp->exp_locks_list, l_exp_refs_link)
-                LDLM_ERROR(lock, "lock:");
-        }
-        cfs_spin_unlock(&exp->exp_locks_list_guard);
+       spin_lock(&exp->exp_locks_list_guard);
+       if (!list_empty(&exp->exp_locks_list)) {
+               struct ldlm_lock *lock;
+
+               CERROR("dumping locks for export %p,"
+                      "ignore if the unmount doesn't hang\n", exp);
+               list_for_each_entry(lock, &exp->exp_locks_list,
+                                       l_exp_refs_link)
+                       LDLM_ERROR(lock, "lock:");
+       }
+       spin_unlock(&exp->exp_locks_list_guard);
 }
 #endif
 
@@ -2623,98 +2928,119 @@ static int target_bulk_timeout(void *data)
         RETURN(1);
 }
 
-static inline char *bulk2type(struct ptlrpc_bulk_desc *desc)
+static inline const char *bulk2type(struct ptlrpc_request *req)
 {
-        return desc->bd_type == BULK_GET_SINK ? "GET" : "PUT";
+       if (req->rq_bulk_read)
+               return "READ";
+       if (req->rq_bulk_write)
+               return "WRITE";
+       return "UNKNOWN";
 }
 
 int target_bulk_io(struct obd_export *exp, struct ptlrpc_bulk_desc *desc,
                    struct l_wait_info *lwi)
 {
-        struct ptlrpc_request *req = desc->bd_req;
-        int rc = 0;
-        ENTRY;
+       struct ptlrpc_request   *req = desc->bd_req;
+       time_t                   start = cfs_time_current_sec();
+       time_t                   deadline;
+       int                      rc = 0;
 
-        /* Check if there is eviction in progress, and if so, wait for
-         * it to finish */
-        if (unlikely(cfs_atomic_read(&exp->exp_obd->obd_evict_inprogress))) {
-                *lwi = LWI_INTR(NULL, NULL);
-                rc = l_wait_event(exp->exp_obd->obd_evict_inprogress_waitq,
-                                  !cfs_atomic_read(&exp->exp_obd->
-                                                   obd_evict_inprogress),
-                                  lwi);
-        }
+       ENTRY;
 
-        /* Check if client was evicted or tried to reconnect already */
-        if (exp->exp_failed || exp->exp_abort_active_req) {
-                rc = -ENOTCONN;
-        } else {
-                if (desc->bd_type == BULK_PUT_SINK)
-                        rc = sptlrpc_svc_wrap_bulk(req, desc);
-                if (rc == 0)
-                        rc = ptlrpc_start_bulk_transfer(desc);
-        }
+       /* If there is eviction in progress, wait for it to finish. */
+       if (unlikely(atomic_read(&exp->exp_obd->obd_evict_inprogress))) {
+               *lwi = LWI_INTR(NULL, NULL);
+               rc = l_wait_event(exp->exp_obd->obd_evict_inprogress_waitq,
+                                 !atomic_read(&exp->exp_obd->
+                                                  obd_evict_inprogress),
+                                 lwi);
+       }
 
-        if (rc == 0 && OBD_FAIL_CHECK(OBD_FAIL_MDS_SENDPAGE)) {
-                ptlrpc_abort_bulk(desc);
-        } else if (rc == 0) {
-                time_t start = cfs_time_current_sec();
-                do {
-                        long timeoutl = req->rq_deadline - cfs_time_current_sec();
-                        cfs_duration_t timeout = timeoutl <= 0 ?
-                                CFS_TICK : cfs_time_seconds(timeoutl);
-                        *lwi = LWI_TIMEOUT_INTERVAL(timeout,
-                                                    cfs_time_seconds(1),
-                                                   target_bulk_timeout,
-                                                   desc);
-                        rc = l_wait_event(desc->bd_waitq,
-                                          !ptlrpc_server_bulk_active(desc) ||
-                                          exp->exp_failed ||
-                                          exp->exp_abort_active_req,
-                                          lwi);
-                        LASSERT(rc == 0 || rc == -ETIMEDOUT);
-                        /* Wait again if we changed deadline */
-                } while ((rc == -ETIMEDOUT) &&
-                         (req->rq_deadline > cfs_time_current_sec()));
-
-                if (rc == -ETIMEDOUT) {
-                        DEBUG_REQ(D_ERROR, req,
-                                  "timeout on bulk %s after %ld%+lds",
-                                  bulk2type(desc),
-                                  req->rq_deadline - start,
-                                  cfs_time_current_sec() -
-                                  req->rq_deadline);
-                        ptlrpc_abort_bulk(desc);
-                } else if (exp->exp_failed) {
-                        DEBUG_REQ(D_ERROR, req, "Eviction on bulk %s",
-                                  bulk2type(desc));
-                        rc = -ENOTCONN;
-                        ptlrpc_abort_bulk(desc);
-                } else if (exp->exp_abort_active_req) {
-                        DEBUG_REQ(D_ERROR, req, "Reconnect on bulk %s",
-                                  bulk2type(desc));
-                        /* we don't reply anyway */
-                        rc = -ETIMEDOUT;
-                        ptlrpc_abort_bulk(desc);
-                } else if (!desc->bd_success ||
-                           desc->bd_nob_transferred != desc->bd_nob) {
-                        DEBUG_REQ(D_ERROR, req, "%s bulk %s %d(%d)",
-                                  desc->bd_success ?
-                                  "truncated" : "network error on",
-                                  bulk2type(desc),
-                                  desc->bd_nob_transferred,
-                                  desc->bd_nob);
-                        /* XXX should this be a different errno? */
-                        rc = -ETIMEDOUT;
-                } else if (desc->bd_type == BULK_GET_SINK) {
-                        rc = sptlrpc_svc_unwrap_bulk(req, desc);
-                }
-        } else {
-                DEBUG_REQ(D_ERROR, req, "bulk %s failed: rc %d",
-                          bulk2type(desc), rc);
-        }
+       /* Check if client was evicted or reconnected already. */
+       if (exp->exp_failed ||
+           exp->exp_conn_cnt > lustre_msg_get_conn_cnt(req->rq_reqmsg)) {
+               rc = -ENOTCONN;
+       } else {
+               if (req->rq_bulk_read)
+                       rc = sptlrpc_svc_wrap_bulk(req, desc);
+               if (rc == 0)
+                       rc = ptlrpc_start_bulk_transfer(desc);
+       }
 
-        RETURN(rc);
+       if (rc < 0) {
+               DEBUG_REQ(D_ERROR, req, "bulk %s failed: rc %d",
+                         bulk2type(req), rc);
+               RETURN(rc);
+       }
+
+       if (OBD_FAIL_CHECK(OBD_FAIL_MDS_SENDPAGE)) {
+               ptlrpc_abort_bulk(desc);
+               RETURN(0);
+       }
+
+       /* limit actual bulk transfer to bulk_timeout seconds */
+       deadline = start + bulk_timeout;
+       if (deadline > req->rq_deadline)
+               deadline = req->rq_deadline;
+
+       do {
+               long timeoutl = deadline - cfs_time_current_sec();
+               cfs_duration_t timeout = timeoutl <= 0 ?
+                                        CFS_TICK : cfs_time_seconds(timeoutl);
+               time_t  rq_deadline;
+
+               *lwi = LWI_TIMEOUT_INTERVAL(timeout, cfs_time_seconds(1),
+                                           target_bulk_timeout, desc);
+               rc = l_wait_event(desc->bd_waitq,
+                                 !ptlrpc_server_bulk_active(desc) ||
+                                 exp->exp_failed ||
+                                 exp->exp_conn_cnt >
+                                 lustre_msg_get_conn_cnt(req->rq_reqmsg),
+                                 lwi);
+               LASSERT(rc == 0 || rc == -ETIMEDOUT);
+               /* Wait again if we changed rq_deadline. */
+               rq_deadline = ACCESS_ONCE(req->rq_deadline);
+               deadline = start + bulk_timeout;
+               if (deadline > rq_deadline)
+                       deadline = rq_deadline;
+       } while ((rc == -ETIMEDOUT) &&
+                (deadline > cfs_time_current_sec()));
+
+       if (rc == -ETIMEDOUT) {
+               DEBUG_REQ(D_ERROR, req, "timeout on bulk %s after %ld%+lds",
+                         bulk2type(req), deadline - start,
+                         cfs_time_current_sec() - deadline);
+               ptlrpc_abort_bulk(desc);
+       } else if (exp->exp_failed) {
+               DEBUG_REQ(D_ERROR, req, "Eviction on bulk %s",
+                         bulk2type(req));
+               rc = -ENOTCONN;
+               ptlrpc_abort_bulk(desc);
+       } else if (exp->exp_conn_cnt >
+                  lustre_msg_get_conn_cnt(req->rq_reqmsg)) {
+               DEBUG_REQ(D_ERROR, req, "Reconnect on bulk %s",
+                         bulk2type(req));
+               /* We don't reply anyway. */
+               rc = -ETIMEDOUT;
+               ptlrpc_abort_bulk(desc);
+       } else if (desc->bd_failure) {
+               DEBUG_REQ(D_ERROR, req, "network error on bulk %s",
+                         bulk2type(req));
+               /* XXX should this be a different errno? */
+               rc = -ETIMEDOUT;
+       } else {
+               if (req->rq_bulk_write)
+                       rc = sptlrpc_svc_unwrap_bulk(req, desc);
+               if (rc == 0 && desc->bd_nob_transferred != desc->bd_nob) {
+                       DEBUG_REQ(D_ERROR, req, "truncated bulk %s %d(%d)",
+                                 bulk2type(req), desc->bd_nob_transferred,
+                                 desc->bd_nob);
+                       /* XXX should this be a different errno? */
+                       rc = -ETIMEDOUT;
+               }
+       }
+
+       RETURN(rc);
 }
 EXPORT_SYMBOL(target_bulk_io);