[mirror_ubuntu-artful-kernel.git] / drivers / staging / lustre / lustre / ldlm / ldlm_lib.c

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2010, 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

/**
 * This file 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

#include "../../include/linux/libcfs/libcfs.h"
#include "../include/obd.h"
#include "../include/obd_class.h"
#include "../include/lustre_dlm.h"
#include "../include/lustre_net.h"
#include "../include/lustre_sec.h"
#include "ldlm_internal.h"

/* @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)
{
        struct ptlrpc_connection *ptlrpc_conn;
        struct obd_import_conn *imp_conn = NULL, *item;
        int rc = 0;

        if (!create && !priority) {
                CDEBUG(D_HA, "Nothing to do\n");
                return -EINVAL;
        }

        ptlrpc_conn = ptlrpc_uuid_to_connection(uuid);
        if (!ptlrpc_conn) {
                CDEBUG(D_HA, "can't find connection %s\n", uuid->uuid);
                return -ENOENT;
        }

        if (create) {
                OBD_ALLOC(imp_conn, sizeof(*imp_conn));
                if (!imp_conn)
                        GOTO(out_put, rc = -ENOMEM);
        }

        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) {
                                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" : ""));
                        spin_unlock(&imp->imp_lock);
                        GOTO(out_free, rc = 0);
                }
        }
        /* 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)
                        list_add(&imp_conn->oic_item, &imp->imp_conn_list);
                else
                        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 {
                spin_unlock(&imp->imp_lock);
                GOTO(out_free, rc = -ENOENT);
        }

        spin_unlock(&imp->imp_lock);
        return 0;
out_free:
        if (imp_conn)
                OBD_FREE(imp_conn, sizeof(*imp_conn));
out_put:
        ptlrpc_connection_put(ptlrpc_conn);
        return rc;
}

int import_set_conn_priority(struct obd_import *imp, struct obd_uuid *uuid)
{
        return import_set_conn(imp, uuid, 1, 0);
}

int client_import_add_conn(struct obd_import *imp, struct obd_uuid *uuid,
                           int priority)
{
        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;

        spin_lock(&imp->imp_lock);
        if (list_empty(&imp->imp_conn_list)) {
                LASSERT(!imp->imp_connection);
                GOTO(out, rc);
        }

        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);

                if (imp_conn == imp->imp_conn_current) {
                        LASSERT(imp_conn->oic_conn == imp->imp_connection);

                        if (imp->imp_state != LUSTRE_IMP_CLOSED &&
                            imp->imp_state != LUSTRE_IMP_DISCON) {
                                CERROR("can't remove current connection\n");
                                GOTO(out, rc = -EBUSY);
                        }

                        ptlrpc_connection_put(imp->imp_connection);
                        imp->imp_connection = NULL;

                        dlmexp = class_conn2export(&imp->imp_dlm_handle);
                        if (dlmexp && dlmexp->exp_connection) {
                                LASSERT(dlmexp->exp_connection ==
                                        imp_conn->oic_conn);
                                ptlrpc_connection_put(dlmexp->exp_connection);
                                dlmexp->exp_connection = NULL;
                        }
                }

                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",
                       imp, imp->imp_obd->obd_name, uuid->uuid);
                rc = 0;
                break;
        }
out:
        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. \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_import_conn *conn;
        int rc = -ENOENT;

        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;
                }
        }
        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 RPCs have finished/aborted
         * to let all busy contexts be released. */
        class_import_get(imp);
        class_destroy_import(imp);
        sptlrpc_import_sec_put(imp);
        class_import_put(imp);
}
EXPORT_SYMBOL(client_destroy_import);

/**
 * 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
 * osc on client
 *      setup 0:{fsname}-OSTxxxx-osc 1:lustre-OST0000_UUID 2:NID
 *
 **/
static int osc_on_mdt(char *obdname)
{
        char *ptr;

        ptr = strrchr(obdname, '-');
        if (ptr == NULL)
                return 0;

        if (strncmp(ptr + 1, "MDT", 3) == 0)
                return 1;

        return 0;
}

/* Configure an RPC client OBD device.
 *
 * lcfg parameters:
 * 1 - client UUID
 * 2 - server UUID
 * 3 - inactive-on-startup
 */
int client_obd_setup(struct obd_device *obddev, struct lustre_cfg *lcfg)
{
        struct client_obd *cli = &obddev->u.cli;
        struct obd_import *imp;
        struct obd_uuid server_uuid;
        int rq_portal, rp_portal, connect_op;
        char *name = obddev->obd_type->typ_name;
        ldlm_ns_type_t ns_type = LDLM_NS_TYPE_UNKNOWN;
        int rc;
        char    *cli_name = lustre_cfg_buf(lcfg, 0);

        /* 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_mdt(cli_name) &&
               strstr(lustre_cfg_buf(lcfg, 1), "OST") != NULL))) {
                /* OSC or OSP_on_MDT for OSTs */
                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_LWP_NAME) ||
                   (!strcmp(name, LUSTRE_OSP_NAME) &&
                    (is_osp_on_mdt(cli_name) &&
                     strstr(lustre_cfg_buf(lcfg, 1), "OST") == NULL))) {
                /* MDC or OSP_on_MDT for other MDTs */
                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_MGC_NAME)) {
                rq_portal = MGS_REQUEST_PORTAL;
                rp_portal = MGC_REPLY_PORTAL;
                connect_op = MGS_CONNECT;
                cli->cl_sp_me = LUSTRE_SP_MGC;
                cli->cl_sp_to = LUSTRE_SP_MGS;
                cli->cl_flvr_mgc.sf_rpc = SPTLRPC_FLVR_INVALID;
                ns_type = LDLM_NS_TYPE_MGC;
        } else {
                CERROR("unknown client OBD type \"%s\", can't setup\n",
                       name);
                return -EINVAL;
        }

        if (LUSTRE_CFG_BUFLEN(lcfg, 1) < 1) {
                CERROR("requires a TARGET UUID\n");
                return -EINVAL;
        }

        if (LUSTRE_CFG_BUFLEN(lcfg, 1) > 37) {
                CERROR("client UUID must be less than 38 characters\n");
                return -EINVAL;
        }

        if (LUSTRE_CFG_BUFLEN(lcfg, 2) < 1) {
                CERROR("setup requires a SERVER UUID\n");
                return -EINVAL;
        }

        if (LUSTRE_CFG_BUFLEN(lcfg, 2) > 37) {
                CERROR("target UUID must be less than 38 characters\n");
                return -EINVAL;
        }

        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 >> PAGE_CACHE_SHIFT > totalram_pages / 8)
                cli->cl_dirty_max = totalram_pages << (PAGE_CACHE_SHIFT - 3);
        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);
        client_obd_list_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_set(&cli->cl_lru_busy, 0);
        atomic_set(&cli->cl_lru_in_list, 0);
        INIT_LIST_HEAD(&cli->cl_lru_list);
        client_obd_list_lock_init(&cli->cl_lru_list_lock);

        init_waitqueue_head(&cli->cl_destroy_waitq);
        atomic_set(&cli->cl_destroy_in_flight, 0);
        /* 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;
        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);

        if (!strcmp(name, LUSTRE_MDC_NAME)) {
                cli->cl_max_rpcs_in_flight = MDC_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;
                else
                        cli->cl_max_rpcs_in_flight = OSC_MAX_RIF_DEFAULT;
        }
        rc = ldlm_get_ref();
        if (rc) {
                CERROR("ldlm_get_ref failed: %d\n", rc);
                GOTO(err, rc);
        }

        ptlrpc_init_client(rq_portal, rp_portal, name,
                           &obddev->obd_ldlm_client);

        imp = class_new_import(obddev);
        if (imp == NULL)
                GOTO(err_ldlm, rc = -ENOENT);
        imp->imp_client = &obddev->obd_ldlm_client;
        imp->imp_connect_op = connect_op;
        memcpy(cli->cl_target_uuid.uuid, lustre_cfg_buf(lcfg, 1),
               LUSTRE_CFG_BUFLEN(lcfg, 1));
        class_import_put(imp);

        rc = client_import_add_conn(imp, &server_uuid, 1);
        if (rc) {
                CERROR("can't add initial connection\n");
                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);

        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);
                        spin_lock(&imp->imp_lock);
                        imp->imp_deactive = 1;
                        spin_unlock(&imp->imp_lock);
                }
        }

        obddev->obd_namespace = ldlm_namespace_new(obddev, obddev->obd_name,
                                                   LDLM_NAMESPACE_CLIENT,
                                                   LDLM_NAMESPACE_GREEDY,
                                                   ns_type);
        if (obddev->obd_namespace == NULL) {
                CERROR("Unable to create client namespace - %s\n",
                       obddev->obd_name);
                GOTO(err_import, rc = -ENOMEM);
        }

        cli->cl_qchk_stat = CL_NOT_QUOTACHECKED;

        return rc;

err_import:
        class_destroy_import(imp);
err_ldlm:
        ldlm_put_ref();
err:
        return rc;

}
EXPORT_SYMBOL(client_obd_setup);

int client_obd_cleanup(struct obd_device *obddev)
{
        ldlm_namespace_free_post(obddev->obd_namespace);
        obddev->obd_namespace = NULL;

        LASSERT(obddev->u.cli.cl_import == NULL);

        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,
                          struct obd_export **exp,
                          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;

        *exp = NULL;
        down_write(&cli->cl_sem);
        if (cli->cl_conn_count > 0 )
                GOTO(out_sem, rc = -EALREADY);

        rc = class_connect(&conn, obd, cluuid);
        if (rc)
                GOTO(out_sem, rc);

        cli->cl_conn_count++;
        *exp = class_conn2export(&conn);

        LASSERT(obd->obd_namespace);

        imp->imp_dlm_handle = conn;
        rc = ptlrpc_init_import(imp);
        if (rc != 0)
                GOTO(out_ldlm, rc);

        ocd = &imp->imp_connect_data;
        if (data) {
                *ocd = *data;
                imp->imp_connect_flags_orig = data->ocd_connect_flags;
        }

        rc = ptlrpc_connect_import(imp);
        if (rc != 0) {
                LASSERT(imp->imp_state == LUSTRE_IMP_DISCON);
                GOTO(out_ldlm, rc);
        }
        LASSERT(*exp != NULL && (*exp)->exp_connection);

        if (data) {
                LASSERTF((ocd->ocd_connect_flags & data->ocd_connect_flags) ==
                         ocd->ocd_connect_flags, "old "LPX64", new "LPX64"\n",
                         data->ocd_connect_flags, ocd->ocd_connect_flags);
                data->ocd_connect_flags = ocd->ocd_connect_flags;
        }

        ptlrpc_pinger_add_import(imp);

        if (rc) {
out_ldlm:
                cli->cl_conn_count--;
                class_disconnect(*exp);
                *exp = NULL;
        }
out_sem:
        up_write(&cli->cl_sem);

        return rc;
}
EXPORT_SYMBOL(client_connect_import);

int client_disconnect_export(struct obd_export *exp)
{
        struct obd_device *obd = class_exp2obd(exp);
        struct client_obd *cli;
        struct obd_import *imp;
        int rc = 0, err;

        if (!obd) {
                CERROR("invalid export for disconnect: exp %p cookie "LPX64"\n",
                       exp, exp ? exp->exp_handle.h_cookie : -1);
                return -EINVAL;
        }

        cli = &obd->u.cli;
        imp = cli->cl_import;

        down_write(&cli->cl_sem);
        CDEBUG(D_INFO, "disconnect %s - %d\n", obd->obd_name,
               cli->cl_conn_count);

        if (!cli->cl_conn_count) {
                CERROR("disconnecting disconnected device (%s)\n",
                       obd->obd_name);
                GOTO(out_disconnect, rc = -EINVAL);
        }

        cli->cl_conn_count--;
        if (cli->cl_conn_count)
                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. */
        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
         * never added.) */
        (void)ptlrpc_pinger_del_import(imp);

        if (obd->obd_namespace != NULL) {
                /* obd_force == local only */
                ldlm_cli_cancel_unused(obd->obd_namespace, NULL,
                                       obd->obd_force ? LCF_LOCAL : 0, NULL);
                ldlm_namespace_free_prior(obd->obd_namespace, imp, obd->obd_force);
        }

        /* 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);

out_disconnect:
        /* Use server style - class_disconnect should be always called for
         * o_disconnect. */
        err = class_disconnect(exp);
        if (!rc && err)
                rc = err;

        up_write(&cli->cl_sem);

        return rc;
}
EXPORT_SYMBOL(client_disconnect_export);


/**
 * Packs current SLV and Limit into \a req.
 */
int target_pack_pool_reply(struct ptlrpc_request *req)
{
        struct obd_device *obd;

        /* 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);
                lustre_msg_set_limit(req->rq_repmsg, 0);
                return 0;
        }

        /* OBD is alive here as export is alive, which we checked above. */
        obd = req->rq_export->exp_obd;

        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);
        read_unlock(&obd->obd_pool_lock);

        return 0;
}
EXPORT_SYMBOL(target_pack_pool_reply);

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");
                return (-ECOMM);
        }

        if (unlikely(rc)) {
                DEBUG_REQ(D_NET, req, "processing error (%d)", rc);
                req->rq_status = rc;
                return (ptlrpc_send_error(req, 1));
        } else {
                DEBUG_REQ(D_NET, req, "sending reply");
        }

        return (ptlrpc_send_reply(req, PTLRPC_REPLY_MAYBE_DIFFICULT));
}

void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id)
{
        struct ptlrpc_service_part *svcpt;
        int                     netrc;
        struct ptlrpc_reply_state *rs;
        struct obd_export        *exp;

        if (req->rq_no_reply)
                return;

        svcpt = req->rq_rqbd->rqbd_svcpt;
        rs = req->rq_reply_state;
        if (rs == NULL || !rs->rs_difficult) {
                /* no notifiers */
                target_send_reply_msg(req, rc, fail_id);
                return;
        }

        /* must be an export if locks saved */
        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(list_empty(&rs->rs_obd_list));
        LASSERT(list_empty(&rs->rs_exp_list));

        exp = class_export_get(req->rq_export);

        /* disable reply scheduling while I'm setting up */
        rs->rs_scheduled = 1;
        rs->rs_on_net    = 1;
        rs->rs_xid       = req->rq_xid;
        rs->rs_transno   = req->rq_transno;
        rs->rs_export    = exp;
        rs->rs_opc       = lustre_msg_get_opc(req->rq_reqmsg);

        spin_lock(&exp->exp_uncommitted_replies_lock);
        CDEBUG(D_NET, "rs transno = %llu, last committed = %llu\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);

        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);

        spin_lock(&svcpt->scp_rep_lock);

        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);
        }

        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 */
        }
        spin_unlock(&rs->rs_lock);
        spin_unlock(&svcpt->scp_rep_lock);
}
EXPORT_SYMBOL(target_send_reply);

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,
};

/**
 * Rather arbitrary mapping from LDLM error codes to errno values. This should
 * not escape to the user level.
 */
int ldlm_error2errno(ldlm_error_t error)
{
        int result;

        switch (error) {
        case ELDLM_OK:
                result = 0;
                break;
        case ELDLM_LOCK_CHANGED:
                result = -ESTALE;
                break;
        case ELDLM_LOCK_ABORTED:
                result = -ENAVAIL;
                break;
        case ELDLM_LOCK_REPLACED:
                result = -ESRCH;
                break;
        case ELDLM_NO_LOCK_DATA:
                result = -ENOENT;
                break;
        case ELDLM_NAMESPACE_EXISTS:
                result = -EEXIST;
                break;
        case ELDLM_BAD_NAMESPACE:
                result = -EBADF;
                break;
        default:
                if (((int)error) < 0)  /* cast to signed type */
                        result = error; /* as ldlm_error_t can be unsigned */
                else {
                        CERROR("Invalid DLM result code: %d\n", error);
                        result = -EPROTO;
                }
        }
        return result;
}
EXPORT_SYMBOL(ldlm_error2errno);

/**
 * Dual to ldlm_error2errno(): maps errno values back to ldlm_error_t.
 */
ldlm_error_t ldlm_errno2error(int err_no)
{
        int error;

        switch (err_no) {
        case 0:
                error = ELDLM_OK;
                break;
        case -ESTALE:
                error = ELDLM_LOCK_CHANGED;
                break;
        case -ENAVAIL:
                error = ELDLM_LOCK_ABORTED;
                break;
        case -ESRCH:
                error = ELDLM_LOCK_REPLACED;
                break;
        case -ENOENT:
                error = ELDLM_NO_LOCK_DATA;
                break;
        case -EEXIST:
                error = ELDLM_NAMESPACE_EXISTS;
                break;
        case -EBADF:
                error = ELDLM_BAD_NAMESPACE;
                break;
        default:
                error = err_no;
        }
        return error;
}
EXPORT_SYMBOL(ldlm_errno2error);

#if LUSTRE_TRACKS_LOCK_EXP_REFS
void ldlm_dump_export_locks(struct obd_export *exp)
{
        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