/*
 * 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) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#define DEBUG_SUBSYSTEM S_LMV
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/mm.h>
#include <asm/div64.h>
#include <linux/seq_file.h>
#include <linux/namei.h>
#include <linux/uaccess.h>

#include "../include/lustre/lustre_idl.h"
#include "../include/obd_support.h"
#include "../include/lustre_lib.h"
#include "../include/lustre_net.h"
#include "../include/obd_class.h"
#include "../include/lprocfs_status.h"
#include "../include/lustre_lite.h"
#include "../include/lustre_fid.h"
#include "../include/lustre_kernelcomm.h"
#include "lmv_internal.h"

static void lmv_activate_target(struct lmv_obd *lmv,
                                struct lmv_tgt_desc *tgt,
                                int activate)
{
        if (tgt->ltd_active == activate)
                return;

        tgt->ltd_active = activate;
        lmv->desc.ld_active_tgt_count += (activate ? 1 : -1);
}

/**
 * Error codes:
 *
 *  -EINVAL  : UUID can't be found in the LMV's target list
 *  -ENOTCONN: The UUID is found, but the target connection is bad (!)
 *  -EBADF   : The UUID is found, but the OBD of the wrong type (!)
 */
static int lmv_set_mdc_active(struct lmv_obd *lmv, struct obd_uuid *uuid,
                              int activate)
{
        struct lmv_tgt_desc    *uninitialized_var(tgt);
        struct obd_device      *obd;
        int                  i;
        int                  rc = 0;

        CDEBUG(D_INFO, "Searching in lmv %p for uuid %s (activate=%d)\n",
               lmv, uuid->uuid, activate);

        spin_lock(&lmv->lmv_lock);
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                tgt = lmv->tgts[i];
                if (!tgt || !tgt->ltd_exp)
                        continue;

                CDEBUG(D_INFO, "Target idx %d is %s conn %#llx\n", i,
                       tgt->ltd_uuid.uuid, tgt->ltd_exp->exp_handle.h_cookie);

                if (obd_uuid_equals(uuid, &tgt->ltd_uuid))
                        break;
        }

        if (i == lmv->desc.ld_tgt_count) {
                rc = -EINVAL;
                goto out_lmv_lock;
        }

        obd = class_exp2obd(tgt->ltd_exp);
        if (!obd) {
                rc = -ENOTCONN;
                goto out_lmv_lock;
        }

        CDEBUG(D_INFO, "Found OBD %s=%s device %d (%p) type %s at LMV idx %d\n",
               obd->obd_name, obd->obd_uuid.uuid, obd->obd_minor, obd,
               obd->obd_type->typ_name, i);
        LASSERT(strcmp(obd->obd_type->typ_name, LUSTRE_MDC_NAME) == 0);

        if (tgt->ltd_active == activate) {
                CDEBUG(D_INFO, "OBD %p already %sactive!\n", obd,
                       activate ? "" : "in");
                goto out_lmv_lock;
        }

        CDEBUG(D_INFO, "Marking OBD %p %sactive\n", obd,
               activate ? "" : "in");
        lmv_activate_target(lmv, tgt, activate);

 out_lmv_lock:
        spin_unlock(&lmv->lmv_lock);
        return rc;
}

static struct obd_uuid *lmv_get_uuid(struct obd_export *exp)
{
        struct lmv_obd *lmv = &exp->exp_obd->u.lmv;

        return obd_get_uuid(lmv->tgts[0]->ltd_exp);
}

static int lmv_notify(struct obd_device *obd, struct obd_device *watched,
                      enum obd_notify_event ev, void *data)
{
        struct obd_connect_data *conn_data;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct obd_uuid  *uuid;
        int                   rc = 0;

        if (strcmp(watched->obd_type->typ_name, LUSTRE_MDC_NAME)) {
                CERROR("unexpected notification of %s %s!\n",
                       watched->obd_type->typ_name,
                       watched->obd_name);
                return -EINVAL;
        }

        uuid = &watched->u.cli.cl_target_uuid;
        if (ev == OBD_NOTIFY_ACTIVE || ev == OBD_NOTIFY_INACTIVE) {
                /*
                 * Set MDC as active before notifying the observer, so the
                 * observer can use the MDC normally.
                 */
                rc = lmv_set_mdc_active(lmv, uuid,
                                        ev == OBD_NOTIFY_ACTIVE);
                if (rc) {
                        CERROR("%sactivation of %s failed: %d\n",
                               ev == OBD_NOTIFY_ACTIVE ? "" : "de",
                               uuid->uuid, rc);
                        return rc;
                }
        } else if (ev == OBD_NOTIFY_OCD) {
                conn_data = &watched->u.cli.cl_import->imp_connect_data;
                /*
                 * XXX: Make sure that ocd_connect_flags from all targets are
                 * the same. Otherwise one of MDTs runs wrong version or
                 * something like this.  --umka
                 */
                obd->obd_self_export->exp_connect_data = *conn_data;
        }
#if 0
        else if (ev == OBD_NOTIFY_DISCON) {
                /*
                 * For disconnect event, flush fld cache for failout MDS case.
                 */
                fld_client_flush(&lmv->lmv_fld);
        }
#endif
        /*
         * Pass the notification up the chain.
         */
        if (obd->obd_observer)
                rc = obd_notify(obd->obd_observer, watched, ev, data);

        return rc;
}

/**
 * This is fake connect function. Its purpose is to initialize lmv and say
 * caller that everything is okay. Real connection will be performed later.
 */
static int lmv_connect(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 lmv_obd  *lmv = &obd->u.lmv;
        struct lustre_handle  conn = { 0 };
        int                 rc = 0;

        /*
         * We don't want to actually do the underlying connections more than
         * once, so keep track.
         */
        lmv->refcount++;
        if (lmv->refcount > 1) {
                *exp = NULL;
                return 0;
        }

        rc = class_connect(&conn, obd, cluuid);
        if (rc) {
                CERROR("class_connection() returned %d\n", rc);
                return rc;
        }

        *exp = class_conn2export(&conn);
        class_export_get(*exp);

        lmv->exp = *exp;
        lmv->connected = 0;
        lmv->cluuid = *cluuid;

        if (data)
                lmv->conn_data = *data;

        lmv->lmv_tgts_kobj = kobject_create_and_add("target_obds",
                                                    &obd->obd_kobj);
        /*
         * All real clients should perform actual connection right away, because
         * it is possible, that LMV will not have opportunity to connect targets
         * and MDC stuff will be called directly, for instance while reading
         * ../mdc/../kbytesfree procfs file, etc.
         */
        if (data && data->ocd_connect_flags & OBD_CONNECT_REAL)
                rc = lmv_check_connect(obd);

        if (rc && lmv->lmv_tgts_kobj)
                kobject_put(lmv->lmv_tgts_kobj);

        return rc;
}

static void lmv_set_timeouts(struct obd_device *obd)
{
        struct lmv_tgt_desc   *tgt;
        struct lmv_obd  *lmv;
        int                 i;

        lmv = &obd->u.lmv;
        if (lmv->server_timeout == 0)
                return;

        if (lmv->connected == 0)
                return;

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                tgt = lmv->tgts[i];
                if (!tgt || !tgt->ltd_exp || tgt->ltd_active == 0)
                        continue;

                obd_set_info_async(NULL, tgt->ltd_exp, sizeof(KEY_INTERMDS),
                                   KEY_INTERMDS, 0, NULL, NULL);
        }
}

static int lmv_init_ea_size(struct obd_export *exp, int easize,
                            int def_easize, int cookiesize, int def_cookiesize)
{
        struct obd_device   *obd = exp->exp_obd;
        struct lmv_obd      *lmv = &obd->u.lmv;
        int               i;
        int               rc = 0;
        int               change = 0;

        if (lmv->max_easize < easize) {
                lmv->max_easize = easize;
                change = 1;
        }
        if (lmv->max_def_easize < def_easize) {
                lmv->max_def_easize = def_easize;
                change = 1;
        }
        if (lmv->max_cookiesize < cookiesize) {
                lmv->max_cookiesize = cookiesize;
                change = 1;
        }
        if (lmv->max_def_cookiesize < def_cookiesize) {
                lmv->max_def_cookiesize = def_cookiesize;
                change = 1;
        }
        if (change == 0)
                return 0;

        if (lmv->connected == 0)
                return 0;

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp ||
                    lmv->tgts[i]->ltd_active == 0) {
                        CWARN("%s: NULL export for %d\n", obd->obd_name, i);
                        continue;
                }

                rc = md_init_ea_size(lmv->tgts[i]->ltd_exp, easize, def_easize,
                                     cookiesize, def_cookiesize);
                if (rc) {
                        CERROR("%s: obd_init_ea_size() failed on MDT target %d: rc = %d\n",
                               obd->obd_name, i, rc);
                        break;
                }
        }
        return rc;
}

#define MAX_STRING_SIZE 128

static int lmv_connect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
{
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct obd_uuid  *cluuid = &lmv->cluuid;
        struct obd_uuid   lmv_mdc_uuid = { "LMV_MDC_UUID" };
        struct obd_device       *mdc_obd;
        struct obd_export       *mdc_exp;
        struct lu_fld_target     target;
        int                   rc;

        mdc_obd = class_find_client_obd(&tgt->ltd_uuid, LUSTRE_MDC_NAME,
                                        &obd->obd_uuid);
        if (!mdc_obd) {
                CERROR("target %s not attached\n", tgt->ltd_uuid.uuid);
                return -EINVAL;
        }

        CDEBUG(D_CONFIG, "connect to %s(%s) - %s, %s FOR %s\n",
               mdc_obd->obd_name, mdc_obd->obd_uuid.uuid,
               tgt->ltd_uuid.uuid, obd->obd_uuid.uuid, cluuid->uuid);

        if (!mdc_obd->obd_set_up) {
                CERROR("target %s is not set up\n", tgt->ltd_uuid.uuid);
                return -EINVAL;
        }

        rc = obd_connect(NULL, &mdc_exp, mdc_obd, &lmv_mdc_uuid,
                         &lmv->conn_data, NULL);
        if (rc) {
                CERROR("target %s connect error %d\n", tgt->ltd_uuid.uuid, rc);
                return rc;
        }

        /*
         * Init fid sequence client for this mdc and add new fld target.
         */
        rc = obd_fid_init(mdc_obd, mdc_exp, LUSTRE_SEQ_METADATA);
        if (rc)
                return rc;

        target.ft_srv = NULL;
        target.ft_exp = mdc_exp;
        target.ft_idx = tgt->ltd_idx;

        fld_client_add_target(&lmv->lmv_fld, &target);

        rc = obd_register_observer(mdc_obd, obd);
        if (rc) {
                obd_disconnect(mdc_exp);
                CERROR("target %s register_observer error %d\n",
                       tgt->ltd_uuid.uuid, rc);
                return rc;
        }

        if (obd->obd_observer) {
                /*
                 * Tell the observer about the new target.
                 */
                rc = obd_notify(obd->obd_observer, mdc_exp->exp_obd,
                                OBD_NOTIFY_ACTIVE,
                                (void *)(tgt - lmv->tgts[0]));
                if (rc) {
                        obd_disconnect(mdc_exp);
                        return rc;
                }
        }

        tgt->ltd_active = 1;
        tgt->ltd_exp = mdc_exp;
        lmv->desc.ld_active_tgt_count++;

        md_init_ea_size(tgt->ltd_exp, lmv->max_easize, lmv->max_def_easize,
                        lmv->max_cookiesize, lmv->max_def_cookiesize);

        CDEBUG(D_CONFIG, "Connected to %s(%s) successfully (%d)\n",
               mdc_obd->obd_name, mdc_obd->obd_uuid.uuid,
               atomic_read(&obd->obd_refcount));

        if (lmv->lmv_tgts_kobj)
                /* Even if we failed to create the link, that's fine */
                rc = sysfs_create_link(lmv->lmv_tgts_kobj, &mdc_obd->obd_kobj,
                                       mdc_obd->obd_name);
        return 0;
}

static void lmv_del_target(struct lmv_obd *lmv, int index)
{
        if (!lmv->tgts[index])
                return;

        kfree(lmv->tgts[index]);
        lmv->tgts[index] = NULL;
        return;
}

static int lmv_add_target(struct obd_device *obd, struct obd_uuid *uuidp,
                          __u32 index, int gen)
{
        struct lmv_obd      *lmv = &obd->u.lmv;
        struct lmv_tgt_desc *tgt;
        int               rc = 0;

        CDEBUG(D_CONFIG, "Target uuid: %s. index %d\n", uuidp->uuid, index);

        lmv_init_lock(lmv);

        if (lmv->desc.ld_tgt_count == 0) {
                struct obd_device *mdc_obd;

                mdc_obd = class_find_client_obd(uuidp, LUSTRE_MDC_NAME,
                                                &obd->obd_uuid);
                if (!mdc_obd) {
                        lmv_init_unlock(lmv);
                        CERROR("%s: Target %s not attached: rc = %d\n",
                               obd->obd_name, uuidp->uuid, -EINVAL);
                        return -EINVAL;
                }
        }

        if ((index < lmv->tgts_size) && lmv->tgts[index]) {
                tgt = lmv->tgts[index];
                CERROR("%s: UUID %s already assigned at LOV target index %d: rc = %d\n",
                       obd->obd_name,
                       obd_uuid2str(&tgt->ltd_uuid), index, -EEXIST);
                lmv_init_unlock(lmv);
                return -EEXIST;
        }

        if (index >= lmv->tgts_size) {
                /* We need to reallocate the lmv target array. */
                struct lmv_tgt_desc **newtgts, **old = NULL;
                __u32 newsize = 1;
                __u32 oldsize = 0;

                while (newsize < index + 1)
                        newsize <<= 1;
                newtgts = kcalloc(newsize, sizeof(*newtgts), GFP_NOFS);
                if (!newtgts) {
                        lmv_init_unlock(lmv);
                        return -ENOMEM;
                }

                if (lmv->tgts_size) {
                        memcpy(newtgts, lmv->tgts,
                               sizeof(*newtgts) * lmv->tgts_size);
                        old = lmv->tgts;
                        oldsize = lmv->tgts_size;
                }

                lmv->tgts = newtgts;
                lmv->tgts_size = newsize;
                smp_rmb();
                kfree(old);

                CDEBUG(D_CONFIG, "tgts: %p size: %d\n", lmv->tgts,
                       lmv->tgts_size);
        }

        tgt = kzalloc(sizeof(*tgt), GFP_NOFS);
        if (!tgt) {
                lmv_init_unlock(lmv);
                return -ENOMEM;
        }

        mutex_init(&tgt->ltd_fid_mutex);
        tgt->ltd_idx = index;
        tgt->ltd_uuid = *uuidp;
        tgt->ltd_active = 0;
        lmv->tgts[index] = tgt;
        if (index >= lmv->desc.ld_tgt_count)
                lmv->desc.ld_tgt_count = index + 1;

        if (lmv->connected) {
                rc = lmv_connect_mdc(obd, tgt);
                if (rc) {
                        spin_lock(&lmv->lmv_lock);
                        lmv->desc.ld_tgt_count--;
                        memset(tgt, 0, sizeof(*tgt));
                        spin_unlock(&lmv->lmv_lock);
                } else {
                        int easize = sizeof(struct lmv_stripe_md) +
                                lmv->desc.ld_tgt_count * sizeof(struct lu_fid);
                        lmv_init_ea_size(obd->obd_self_export, easize, 0, 0, 0);
                }
        }

        lmv_init_unlock(lmv);
        return rc;
}

int lmv_check_connect(struct obd_device *obd)
{
        struct lmv_obd       *lmv = &obd->u.lmv;
        struct lmv_tgt_desc  *tgt;
        int                i;
        int                rc;
        int                easize;

        if (lmv->connected)
                return 0;

        lmv_init_lock(lmv);
        if (lmv->connected) {
                lmv_init_unlock(lmv);
                return 0;
        }

        if (lmv->desc.ld_tgt_count == 0) {
                lmv_init_unlock(lmv);
                CERROR("%s: no targets configured.\n", obd->obd_name);
                return -EINVAL;
        }

        CDEBUG(D_CONFIG, "Time to connect %s to %s\n",
               lmv->cluuid.uuid, obd->obd_name);

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                tgt = lmv->tgts[i];
                if (!tgt)
                        continue;
                rc = lmv_connect_mdc(obd, tgt);
                if (rc)
                        goto out_disc;
        }

        lmv_set_timeouts(obd);
        class_export_put(lmv->exp);
        lmv->connected = 1;
        easize = lmv_get_easize(lmv);
        lmv_init_ea_size(obd->obd_self_export, easize, 0, 0, 0);
        lmv_init_unlock(lmv);
        return 0;

 out_disc:
        while (i-- > 0) {
                int rc2;

                tgt = lmv->tgts[i];
                if (!tgt)
                        continue;
                tgt->ltd_active = 0;
                if (tgt->ltd_exp) {
                        --lmv->desc.ld_active_tgt_count;
                        rc2 = obd_disconnect(tgt->ltd_exp);
                        if (rc2) {
                                CERROR("LMV target %s disconnect on MDC idx %d: error %d\n",
                                       tgt->ltd_uuid.uuid, i, rc2);
                        }
                }
        }
        class_disconnect(lmv->exp);
        lmv_init_unlock(lmv);
        return rc;
}

static int lmv_disconnect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
{
        struct lmv_obd   *lmv = &obd->u.lmv;
        struct obd_device      *mdc_obd;
        int                  rc;

        mdc_obd = class_exp2obd(tgt->ltd_exp);

        if (mdc_obd) {
                mdc_obd->obd_force = obd->obd_force;
                mdc_obd->obd_fail = obd->obd_fail;
                mdc_obd->obd_no_recov = obd->obd_no_recov;

                if (lmv->lmv_tgts_kobj)
                        sysfs_remove_link(lmv->lmv_tgts_kobj,
                                          mdc_obd->obd_name);
        }

        rc = obd_fid_fini(tgt->ltd_exp->exp_obd);
        if (rc)
                CERROR("Can't finalize fids factory\n");

        CDEBUG(D_INFO, "Disconnected from %s(%s) successfully\n",
               tgt->ltd_exp->exp_obd->obd_name,
               tgt->ltd_exp->exp_obd->obd_uuid.uuid);

        obd_register_observer(tgt->ltd_exp->exp_obd, NULL);
        rc = obd_disconnect(tgt->ltd_exp);
        if (rc) {
                if (tgt->ltd_active) {
                        CERROR("Target %s disconnect error %d\n",
                               tgt->ltd_uuid.uuid, rc);
                }
        }

        lmv_activate_target(lmv, tgt, 0);
        tgt->ltd_exp = NULL;
        return 0;
}

static int lmv_disconnect(struct obd_export *exp)
{
        struct obd_device     *obd = class_exp2obd(exp);
        struct lmv_obd  *lmv = &obd->u.lmv;
        int                 rc;
        int                 i;

        if (!lmv->tgts)
                goto out_local;

        /*
         * Only disconnect the underlying layers on the final disconnect.
         */
        lmv->refcount--;
        if (lmv->refcount != 0)
                goto out_local;

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp)
                        continue;

                lmv_disconnect_mdc(obd, lmv->tgts[i]);
        }

        if (lmv->lmv_tgts_kobj)
                kobject_put(lmv->lmv_tgts_kobj);

out_local:
        /*
         * This is the case when no real connection is established by
         * lmv_check_connect().
         */
        if (!lmv->connected)
                class_export_put(exp);
        rc = class_disconnect(exp);
        if (lmv->refcount == 0)
                lmv->connected = 0;
        return rc;
}

static int lmv_fid2path(struct obd_export *exp, int len, void *karg,
                        void __user *uarg)
{
        struct obd_device       *obddev = class_exp2obd(exp);
        struct lmv_obd          *lmv = &obddev->u.lmv;
        struct getinfo_fid2path *gf;
        struct lmv_tgt_desc     *tgt;
        struct getinfo_fid2path *remote_gf = NULL;
        int                     remote_gf_size = 0;
        int                     rc;

        gf = (struct getinfo_fid2path *)karg;
        tgt = lmv_find_target(lmv, &gf->gf_fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

repeat_fid2path:
        rc = obd_iocontrol(OBD_IOC_FID2PATH, tgt->ltd_exp, len, gf, uarg);
        if (rc != 0 && rc != -EREMOTE)
                goto out_fid2path;

        /* If remote_gf != NULL, it means just building the
         * path on the remote MDT, copy this path segment to gf
         */
        if (remote_gf) {
                struct getinfo_fid2path *ori_gf;
                char *ptr;

                ori_gf = (struct getinfo_fid2path *)karg;
                if (strlen(ori_gf->gf_path) +
                    strlen(gf->gf_path) > ori_gf->gf_pathlen) {
                        rc = -EOVERFLOW;
                        goto out_fid2path;
                }

                ptr = ori_gf->gf_path;

                memmove(ptr + strlen(gf->gf_path) + 1, ptr,
                        strlen(ori_gf->gf_path));

                strncpy(ptr, gf->gf_path, strlen(gf->gf_path));
                ptr += strlen(gf->gf_path);
                *ptr = '/';
        }

        CDEBUG(D_INFO, "%s: get path %s "DFID" rec: %llu ln: %u\n",
               tgt->ltd_exp->exp_obd->obd_name,
               gf->gf_path, PFID(&gf->gf_fid), gf->gf_recno,
               gf->gf_linkno);

        if (rc == 0)
                goto out_fid2path;

        /* sigh, has to go to another MDT to do path building further */
        if (!remote_gf) {
                remote_gf_size = sizeof(*remote_gf) + PATH_MAX;
                remote_gf = kzalloc(remote_gf_size, GFP_NOFS);
                if (!remote_gf) {
                        rc = -ENOMEM;
                        goto out_fid2path;
                }
                remote_gf->gf_pathlen = PATH_MAX;
        }

        if (!fid_is_sane(&gf->gf_fid)) {
                CERROR("%s: invalid FID "DFID": rc = %d\n",
                       tgt->ltd_exp->exp_obd->obd_name,
                       PFID(&gf->gf_fid), -EINVAL);
                rc = -EINVAL;
                goto out_fid2path;
        }

        tgt = lmv_find_target(lmv, &gf->gf_fid);
        if (IS_ERR(tgt)) {
                rc = -EINVAL;
                goto out_fid2path;
        }

        remote_gf->gf_fid = gf->gf_fid;
        remote_gf->gf_recno = -1;
        remote_gf->gf_linkno = -1;
        memset(remote_gf->gf_path, 0, remote_gf->gf_pathlen);
        gf = remote_gf;
        goto repeat_fid2path;

out_fid2path:
        kfree(remote_gf);
        return rc;
}

static int lmv_hsm_req_count(struct lmv_obd *lmv,
                             const struct hsm_user_request *hur,
                             const struct lmv_tgt_desc *tgt_mds)
{
        int                     i, nr = 0;
        struct lmv_tgt_desc    *curr_tgt;

        /* count how many requests must be sent to the given target */
        for (i = 0; i < hur->hur_request.hr_itemcount; i++) {
                curr_tgt = lmv_find_target(lmv, &hur->hur_user_item[i].hui_fid);
                if (obd_uuid_equals(&curr_tgt->ltd_uuid, &tgt_mds->ltd_uuid))
                        nr++;
        }
        return nr;
}

static void lmv_hsm_req_build(struct lmv_obd *lmv,
                              struct hsm_user_request *hur_in,
                              const struct lmv_tgt_desc *tgt_mds,
                              struct hsm_user_request *hur_out)
{
        int                     i, nr_out;
        struct lmv_tgt_desc    *curr_tgt;

        /* build the hsm_user_request for the given target */
        hur_out->hur_request = hur_in->hur_request;
        nr_out = 0;
        for (i = 0; i < hur_in->hur_request.hr_itemcount; i++) {
                curr_tgt = lmv_find_target(lmv,
                                           &hur_in->hur_user_item[i].hui_fid);
                if (obd_uuid_equals(&curr_tgt->ltd_uuid, &tgt_mds->ltd_uuid)) {
                        hur_out->hur_user_item[nr_out] =
                                hur_in->hur_user_item[i];
                        nr_out++;
                }
        }
        hur_out->hur_request.hr_itemcount = nr_out;
        memcpy(hur_data(hur_out), hur_data(hur_in),
               hur_in->hur_request.hr_data_len);
}

static int lmv_hsm_ct_unregister(struct lmv_obd *lmv, unsigned int cmd, int len,
                                 struct lustre_kernelcomm *lk,
                                 void __user *uarg)
{
        int rc = 0;
        __u32 i;

        /* unregister request (call from llapi_hsm_copytool_fini) */
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                /* best effort: try to clean as much as possible
                 * (continue on error)
                 */
                obd_iocontrol(cmd, lmv->tgts[i]->ltd_exp, len, lk, uarg);
        }

        /* Whatever the result, remove copytool from kuc groups.
         * Unreached coordinators will get EPIPE on next requests
         * and will unregister automatically.
         */
        rc = libcfs_kkuc_group_rem(lk->lk_uid, lk->lk_group);

        return rc;
}

static int lmv_hsm_ct_register(struct lmv_obd *lmv, unsigned int cmd, int len,
                               struct lustre_kernelcomm *lk, void __user *uarg)
{
        struct file *filp;
        __u32 i, j;
        int err, rc = 0;
        bool any_set = false;
        struct kkuc_ct_data kcd = { 0 };

        /* All or nothing: try to register to all MDS.
         * In case of failure, unregister from previous MDS,
         * except if it because of inactive target.
         */
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                err = obd_iocontrol(cmd, lmv->tgts[i]->ltd_exp, len, lk, uarg);
                if (err) {
                        if (lmv->tgts[i]->ltd_active) {
                                /* permanent error */
                                CERROR("error: iocontrol MDC %s on MDTidx %d cmd %x: err = %d\n",
                                       lmv->tgts[i]->ltd_uuid.uuid,
                                       i, cmd, err);
                                rc = err;
                                lk->lk_flags |= LK_FLG_STOP;
                                /* unregister from previous MDS */
                                for (j = 0; j < i; j++)
                                        obd_iocontrol(cmd,
                                                      lmv->tgts[j]->ltd_exp,
                                                      len, lk, uarg);
                                return rc;
                        }
                        /* else: transient error.
                         * kuc will register to the missing MDT when it is back
                         */
                } else {
                        any_set = true;
                }
        }

        if (!any_set)
                /* no registration done: return error */
                return -ENOTCONN;

        /* at least one registration done, with no failure */
        filp = fget(lk->lk_wfd);
        if (!filp)
                return -EBADF;

        kcd.kcd_magic = KKUC_CT_DATA_MAGIC;
        kcd.kcd_uuid = lmv->cluuid;
        kcd.kcd_archive = lk->lk_data;

        rc = libcfs_kkuc_group_add(filp, lk->lk_uid, lk->lk_group,
                                   &kcd, sizeof(kcd));
        if (rc) {
                if (filp)
                        fput(filp);
        }

        return rc;
}

static int lmv_iocontrol(unsigned int cmd, struct obd_export *exp,
                         int len, void *karg, void __user *uarg)
{
        struct obd_device    *obddev = class_exp2obd(exp);
        struct lmv_obd       *lmv = &obddev->u.lmv;
        int                i = 0;
        int                rc = 0;
        int                set = 0;
        int                count = lmv->desc.ld_tgt_count;

        if (count == 0)
                return -ENOTTY;

        switch (cmd) {
        case IOC_OBD_STATFS: {
                struct obd_ioctl_data *data = karg;
                struct obd_device *mdc_obd;
                struct obd_statfs stat_buf = {0};
                __u32 index;

                memcpy(&index, data->ioc_inlbuf2, sizeof(__u32));
                if (index >= count)
                        return -ENODEV;

                if (!lmv->tgts[index] || lmv->tgts[index]->ltd_active == 0)
                        return -ENODATA;

                mdc_obd = class_exp2obd(lmv->tgts[index]->ltd_exp);
                if (!mdc_obd)
                        return -EINVAL;

                /* copy UUID */
                if (copy_to_user(data->ioc_pbuf2, obd2cli_tgt(mdc_obd),
                                 min((int)data->ioc_plen2,
                                     (int)sizeof(struct obd_uuid))))
                        return -EFAULT;

                rc = obd_statfs(NULL, lmv->tgts[index]->ltd_exp, &stat_buf,
                                cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
                                0);
                if (rc)
                        return rc;
                if (copy_to_user(data->ioc_pbuf1, &stat_buf,
                                 min((int)data->ioc_plen1,
                                     (int)sizeof(stat_buf))))
                        return -EFAULT;
                break;
        }
        case OBD_IOC_QUOTACTL: {
                struct if_quotactl *qctl = karg;
                struct lmv_tgt_desc *tgt = NULL;
                struct obd_quotactl *oqctl;

                if (qctl->qc_valid == QC_MDTIDX) {
                        if (qctl->qc_idx < 0 || count <= qctl->qc_idx)
                                return -EINVAL;

                        tgt = lmv->tgts[qctl->qc_idx];
                        if (!tgt || !tgt->ltd_exp)
                                return -EINVAL;
                } else if (qctl->qc_valid == QC_UUID) {
                        for (i = 0; i < count; i++) {
                                tgt = lmv->tgts[i];
                                if (!tgt)
                                        continue;
                                if (!obd_uuid_equals(&tgt->ltd_uuid,
                                                     &qctl->obd_uuid))
                                        continue;

                                if (!tgt->ltd_exp)
                                        return -EINVAL;

                                break;
                        }
                } else {
                        return -EINVAL;
                }

                if (i >= count)
                        return -EAGAIN;

                LASSERT(tgt && tgt->ltd_exp);
                oqctl = kzalloc(sizeof(*oqctl), GFP_NOFS);
                if (!oqctl)
                        return -ENOMEM;

                QCTL_COPY(oqctl, qctl);
                rc = obd_quotactl(tgt->ltd_exp, oqctl);
                if (rc == 0) {
                        QCTL_COPY(qctl, oqctl);
                        qctl->qc_valid = QC_MDTIDX;
                        qctl->obd_uuid = tgt->ltd_uuid;
                }
                kfree(oqctl);
                break;
        }
        case OBD_IOC_CHANGELOG_SEND:
        case OBD_IOC_CHANGELOG_CLEAR: {
                struct ioc_changelog *icc = karg;

                if (icc->icc_mdtindex >= count)
                        return -ENODEV;

                if (!lmv->tgts[icc->icc_mdtindex] ||
                    !lmv->tgts[icc->icc_mdtindex]->ltd_exp ||
                    lmv->tgts[icc->icc_mdtindex]->ltd_active == 0)
                        return -ENODEV;
                rc = obd_iocontrol(cmd, lmv->tgts[icc->icc_mdtindex]->ltd_exp,
                                   sizeof(*icc), icc, NULL);
                break;
        }
        case LL_IOC_GET_CONNECT_FLAGS: {
                if (!lmv->tgts[0])
                        return -ENODATA;
                rc = obd_iocontrol(cmd, lmv->tgts[0]->ltd_exp, len, karg, uarg);
                break;
        }
        case OBD_IOC_FID2PATH: {
                rc = lmv_fid2path(exp, len, karg, uarg);
                break;
        }
        case LL_IOC_HSM_STATE_GET:
        case LL_IOC_HSM_STATE_SET:
        case LL_IOC_HSM_ACTION: {
                struct md_op_data       *op_data = karg;
                struct lmv_tgt_desc     *tgt;

                tgt = lmv_find_target(lmv, &op_data->op_fid1);
                if (IS_ERR(tgt))
                        return PTR_ERR(tgt);

                if (!tgt->ltd_exp)
                        return -EINVAL;

                rc = obd_iocontrol(cmd, tgt->ltd_exp, len, karg, uarg);
                break;
        }
        case LL_IOC_HSM_PROGRESS: {
                const struct hsm_progress_kernel *hpk = karg;
                struct lmv_tgt_desc     *tgt;

                tgt = lmv_find_target(lmv, &hpk->hpk_fid);
                if (IS_ERR(tgt))
                        return PTR_ERR(tgt);
                rc = obd_iocontrol(cmd, tgt->ltd_exp, len, karg, uarg);
                break;
        }
        case LL_IOC_HSM_REQUEST: {
                struct hsm_user_request *hur = karg;
                struct lmv_tgt_desc     *tgt;
                unsigned int reqcount = hur->hur_request.hr_itemcount;

                if (reqcount == 0)
                        return 0;

                /* if the request is about a single fid
                 * or if there is a single MDS, no need to split
                 * the request.
                 */
                if (reqcount == 1 || count == 1) {
                        tgt = lmv_find_target(lmv,
                                              &hur->hur_user_item[0].hui_fid);
                        if (IS_ERR(tgt))
                                return PTR_ERR(tgt);
                        rc = obd_iocontrol(cmd, tgt->ltd_exp, len, karg, uarg);
                } else {
                        /* split fid list to their respective MDS */
                        for (i = 0; i < count; i++) {
                                unsigned int            nr, reqlen;
                                int                     rc1;
                                struct hsm_user_request *req;

                                nr = lmv_hsm_req_count(lmv, hur, lmv->tgts[i]);
                                if (nr == 0) /* nothing for this MDS */
                                        continue;

                                /* build a request with fids for this MDS */
                                reqlen = offsetof(typeof(*hur),
                                                  hur_user_item[nr])
                                         + hur->hur_request.hr_data_len;
                                req = libcfs_kvzalloc(reqlen, GFP_NOFS);
                                if (!req)
                                        return -ENOMEM;

                                lmv_hsm_req_build(lmv, hur, lmv->tgts[i], req);

                                rc1 = obd_iocontrol(cmd, lmv->tgts[i]->ltd_exp,
                                                    reqlen, req, uarg);
                                if (rc1 != 0 && rc == 0)
                                        rc = rc1;
                                kvfree(req);
                        }
                }
                break;
        }
        case LL_IOC_LOV_SWAP_LAYOUTS: {
                struct md_op_data       *op_data = karg;
                struct lmv_tgt_desc     *tgt1, *tgt2;

                tgt1 = lmv_find_target(lmv, &op_data->op_fid1);
                if (IS_ERR(tgt1))
                        return PTR_ERR(tgt1);

                tgt2 = lmv_find_target(lmv, &op_data->op_fid2);
                if (IS_ERR(tgt2))
                        return PTR_ERR(tgt2);

                if (!tgt1->ltd_exp || !tgt2->ltd_exp)
                        return -EINVAL;

                /* only files on same MDT can have their layouts swapped */
                if (tgt1->ltd_idx != tgt2->ltd_idx)
                        return -EPERM;

                rc = obd_iocontrol(cmd, tgt1->ltd_exp, len, karg, uarg);
                break;
        }
        case LL_IOC_HSM_CT_START: {
                struct lustre_kernelcomm *lk = karg;

                if (lk->lk_flags & LK_FLG_STOP)
                        rc = lmv_hsm_ct_unregister(lmv, cmd, len, lk, uarg);
                else
                        rc = lmv_hsm_ct_register(lmv, cmd, len, lk, uarg);
                break;
        }
        default:
                for (i = 0; i < count; i++) {
                        struct obd_device *mdc_obd;
                        int err;

                        if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp)
                                continue;
                        /* ll_umount_begin() sets force flag but for lmv, not
                         * mdc. Let's pass it through
                         */
                        mdc_obd = class_exp2obd(lmv->tgts[i]->ltd_exp);
                        mdc_obd->obd_force = obddev->obd_force;
                        err = obd_iocontrol(cmd, lmv->tgts[i]->ltd_exp, len,
                                            karg, uarg);
                        if (err == -ENODATA && cmd == OBD_IOC_POLL_QUOTACHECK) {
                                return err;
                        } else if (err) {
                                if (lmv->tgts[i]->ltd_active) {
                                        CERROR("error: iocontrol MDC %s on MDTidx %d cmd %x: err = %d\n",
                                               lmv->tgts[i]->ltd_uuid.uuid,
                                               i, cmd, err);
                                        if (!rc)
                                                rc = err;
                                }
                        } else
                                set = 1;
                }
                if (!set && !rc)
                        rc = -EIO;
        }
        return rc;
}

/**
 * This is _inode_ placement policy function (not name).
 */
static int lmv_placement_policy(struct obd_device *obd,
                                struct md_op_data *op_data, u32 *mds)
{
        struct lmv_obd    *lmv = &obd->u.lmv;

        LASSERT(mds);

        if (lmv->desc.ld_tgt_count == 1) {
                *mds = 0;
                return 0;
        }

        /**
         * If stripe_offset is provided during setdirstripe
         * (setdirstripe -i xx), xx MDS will be chosen.
         */
        if (op_data->op_cli_flags & CLI_SET_MEA) {
                struct lmv_user_md *lum;

                lum = (struct lmv_user_md *)op_data->op_data;
                if (lum->lum_type == LMV_STRIPE_TYPE &&
                    lum->lum_stripe_offset != -1) {
                        if (lum->lum_stripe_offset >= lmv->desc.ld_tgt_count) {
                                CERROR("%s: Stripe_offset %d > MDT count %d: rc = %d\n",
                                       obd->obd_name,
                                       lum->lum_stripe_offset,
                                       lmv->desc.ld_tgt_count, -ERANGE);
                                return -ERANGE;
                        }
                        *mds = lum->lum_stripe_offset;
                        return 0;
                }
        }

        /* Allocate new fid on target according to operation type and parent
         * home mds.
         */
        *mds = op_data->op_mds;
        return 0;
}

int __lmv_fid_alloc(struct lmv_obd *lmv, struct lu_fid *fid, u32 mds)
{
        struct lmv_tgt_desc     *tgt;
        int                      rc;

        tgt = lmv_get_target(lmv, mds);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        /*
         * New seq alloc and FLD setup should be atomic. Otherwise we may find
         * on server that seq in new allocated fid is not yet known.
         */
        mutex_lock(&tgt->ltd_fid_mutex);

        if (tgt->ltd_active == 0 || !tgt->ltd_exp) {
                rc = -ENODEV;
                goto out;
        }

        /*
         * Asking underlaying tgt layer to allocate new fid.
         */
        rc = obd_fid_alloc(tgt->ltd_exp, fid, NULL);
        if (rc > 0) {
                LASSERT(fid_is_sane(fid));
                rc = 0;
        }

out:
        mutex_unlock(&tgt->ltd_fid_mutex);
        return rc;
}

int lmv_fid_alloc(struct obd_export *exp, struct lu_fid *fid,
                  struct md_op_data *op_data)
{
        struct obd_device     *obd = class_exp2obd(exp);
        struct lmv_obd  *lmv = &obd->u.lmv;
        u32                    mds = 0;
        int                 rc;

        LASSERT(op_data);
        LASSERT(fid);

        rc = lmv_placement_policy(obd, op_data, &mds);
        if (rc) {
                CERROR("Can't get target for allocating fid, rc %d\n",
                       rc);
                return rc;
        }

        rc = __lmv_fid_alloc(lmv, fid, mds);
        if (rc) {
                CERROR("Can't alloc new fid, rc %d\n", rc);
                return rc;
        }

        return rc;
}

static int lmv_setup(struct obd_device *obd, struct lustre_cfg *lcfg)
{
        struct lmv_obd       *lmv = &obd->u.lmv;
        struct lprocfs_static_vars  lvars = { NULL };
        struct lmv_desc     *desc;
        int                      rc;

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

        desc = (struct lmv_desc *)lustre_cfg_buf(lcfg, 1);
        if (sizeof(*desc) > LUSTRE_CFG_BUFLEN(lcfg, 1)) {
                CERROR("Lmv descriptor size wrong: %d > %d\n",
                       (int)sizeof(*desc), LUSTRE_CFG_BUFLEN(lcfg, 1));
                return -EINVAL;
        }

        lmv->tgts = kcalloc(32, sizeof(*lmv->tgts), GFP_NOFS);
        if (!lmv->tgts)
                return -ENOMEM;
        lmv->tgts_size = 32;

        obd_str2uuid(&lmv->desc.ld_uuid, desc->ld_uuid.uuid);
        lmv->desc.ld_tgt_count = 0;
        lmv->desc.ld_active_tgt_count = 0;
        lmv->max_cookiesize = 0;
        lmv->max_def_easize = 0;
        lmv->max_easize = 0;
        lmv->lmv_placement = PLACEMENT_CHAR_POLICY;

        spin_lock_init(&lmv->lmv_lock);
        mutex_init(&lmv->init_mutex);

        lprocfs_lmv_init_vars(&lvars);

        lprocfs_obd_setup(obd, lvars.obd_vars, lvars.sysfs_vars);
        rc = ldebugfs_seq_create(obd->obd_debugfs_entry, "target_obd",
                                 0444, &lmv_proc_target_fops, obd);
        if (rc)
                CWARN("%s: error adding LMV target_obd file: rc = %d\n",
                      obd->obd_name, rc);
        rc = fld_client_init(&lmv->lmv_fld, obd->obd_name,
                             LUSTRE_CLI_FLD_HASH_DHT);
        if (rc) {
                CERROR("Can't init FLD, err %d\n", rc);
                goto out;
        }

        return 0;

out:
        return rc;
}

static int lmv_cleanup(struct obd_device *obd)
{
        struct lmv_obd   *lmv = &obd->u.lmv;

        fld_client_fini(&lmv->lmv_fld);
        if (lmv->tgts) {
                int i;

                for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                        if (!lmv->tgts[i])
                                continue;
                        lmv_del_target(lmv, i);
                }
                kfree(lmv->tgts);
                lmv->tgts_size = 0;
        }
        return 0;
}

static int lmv_process_config(struct obd_device *obd, u32 len, void *buf)
{
        struct lustre_cfg       *lcfg = buf;
        struct obd_uuid         obd_uuid;
        int                     gen;
        __u32                   index;
        int                     rc;

        switch (lcfg->lcfg_command) {
        case LCFG_ADD_MDC:
                /* modify_mdc_tgts add 0:lustre-clilmv  1:lustre-MDT0000_UUID
                 * 2:0  3:1  4:lustre-MDT0000-mdc_UUID
                 */
                if (LUSTRE_CFG_BUFLEN(lcfg, 1) > sizeof(obd_uuid.uuid)) {
                        rc = -EINVAL;
                        goto out;
                }

                obd_str2uuid(&obd_uuid,  lustre_cfg_buf(lcfg, 1));

                if (sscanf(lustre_cfg_buf(lcfg, 2), "%d", &index) != 1) {
                        rc = -EINVAL;
                        goto out;
                }
                if (sscanf(lustre_cfg_buf(lcfg, 3), "%d", &gen) != 1) {
                        rc = -EINVAL;
                        goto out;
                }
                rc = lmv_add_target(obd, &obd_uuid, index, gen);
                goto out;
        default:
                CERROR("Unknown command: %d\n", lcfg->lcfg_command);
                rc = -EINVAL;
                goto out;
        }
out:
        return rc;
}

static int lmv_statfs(const struct lu_env *env, struct obd_export *exp,
                      struct obd_statfs *osfs, __u64 max_age, __u32 flags)
{
        struct obd_device     *obd = class_exp2obd(exp);
        struct lmv_obd  *lmv = &obd->u.lmv;
        struct obd_statfs     *temp;
        int                 rc = 0;
        int                 i;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        temp = kzalloc(sizeof(*temp), GFP_NOFS);
        if (!temp)
                return -ENOMEM;

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp)
                        continue;

                rc = obd_statfs(env, lmv->tgts[i]->ltd_exp, temp,
                                max_age, flags);
                if (rc) {
                        CERROR("can't stat MDS #%d (%s), error %d\n", i,
                               lmv->tgts[i]->ltd_exp->exp_obd->obd_name,
                               rc);
                        goto out_free_temp;
                }

                if (i == 0) {
                        *osfs = *temp;
                        /* If the statfs is from mount, it will needs
                         * retrieve necessary information from MDT0.
                         * i.e. mount does not need the merged osfs
                         * from all of MDT.
                         * And also clients can be mounted as long as
                         * MDT0 is in service
                         */
                        if (flags & OBD_STATFS_FOR_MDT0)
                                goto out_free_temp;
                } else {
                        osfs->os_bavail += temp->os_bavail;
                        osfs->os_blocks += temp->os_blocks;
                        osfs->os_ffree += temp->os_ffree;
                        osfs->os_files += temp->os_files;
                }
        }

out_free_temp:
        kfree(temp);
        return rc;
}

static int lmv_getstatus(struct obd_export *exp,
                         struct lu_fid *fid)
{
        struct obd_device    *obd = exp->exp_obd;
        struct lmv_obd       *lmv = &obd->u.lmv;
        int                rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        rc = md_getstatus(lmv->tgts[0]->ltd_exp, fid);
        return rc;
}

static int lmv_getxattr(struct obd_export *exp, const struct lu_fid *fid,
                        u64 valid, const char *name,
                        const char *input, int input_size, int output_size,
                        int flags, struct ptlrpc_request **request)
{
        struct obd_device      *obd = exp->exp_obd;
        struct lmv_obd   *lmv = &obd->u.lmv;
        struct lmv_tgt_desc    *tgt;
        int                  rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_getxattr(tgt->ltd_exp, fid, valid, name, input,
                         input_size, output_size, flags, request);

        return rc;
}

static int lmv_setxattr(struct obd_export *exp, const struct lu_fid *fid,
                        u64 valid, const char *name,
                        const char *input, int input_size, int output_size,
                        int flags, __u32 suppgid,
                        struct ptlrpc_request **request)
{
        struct obd_device      *obd = exp->exp_obd;
        struct lmv_obd   *lmv = &obd->u.lmv;
        struct lmv_tgt_desc    *tgt;
        int                  rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_setxattr(tgt->ltd_exp, fid, valid, name, input,
                         input_size, output_size, flags, suppgid,
                         request);

        return rc;
}

static int lmv_getattr(struct obd_export *exp, struct md_op_data *op_data,
                       struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        if (op_data->op_flags & MF_GET_MDT_IDX) {
                op_data->op_mds = tgt->ltd_idx;
                return 0;
        }

        rc = md_getattr(tgt->ltd_exp, op_data, request);

        return rc;
}

static int lmv_null_inode(struct obd_export *exp, const struct lu_fid *fid)
{
        struct obd_device   *obd = exp->exp_obd;
        struct lmv_obd      *lmv = &obd->u.lmv;
        int               i;
        int               rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        CDEBUG(D_INODE, "CBDATA for "DFID"\n", PFID(fid));

        /*
         * With DNE every object can have two locks in different namespaces:
         * lookup lock in space of MDT storing direntry and update/open lock in
         * space of MDT storing inode.
         */
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp)
                        continue;
                md_null_inode(lmv->tgts[i]->ltd_exp, fid);
        }

        return 0;
}

static int lmv_find_cbdata(struct obd_export *exp, const struct lu_fid *fid,
                           ldlm_iterator_t it, void *data)
{
        struct obd_device   *obd = exp->exp_obd;
        struct lmv_obd      *lmv = &obd->u.lmv;
        int               i;
        int               rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        CDEBUG(D_INODE, "CBDATA for "DFID"\n", PFID(fid));

        /*
         * With DNE every object can have two locks in different namespaces:
         * lookup lock in space of MDT storing direntry and update/open lock in
         * space of MDT storing inode.
         */
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp)
                        continue;
                rc = md_find_cbdata(lmv->tgts[i]->ltd_exp, fid, it, data);
                if (rc)
                        return rc;
        }

        return rc;
}

static int lmv_close(struct obd_export *exp, struct md_op_data *op_data,
                     struct md_open_data *mod, struct ptlrpc_request **request)
{
        struct obd_device     *obd = exp->exp_obd;
        struct lmv_obd  *lmv = &obd->u.lmv;
        struct lmv_tgt_desc   *tgt;
        int                 rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        CDEBUG(D_INODE, "CLOSE "DFID"\n", PFID(&op_data->op_fid1));
        rc = md_close(tgt->ltd_exp, op_data, mod, request);
        return rc;
}

struct lmv_tgt_desc
*lmv_locate_mds(struct lmv_obd *lmv, struct md_op_data *op_data,
                struct lu_fid *fid)
{
        struct lmv_tgt_desc *tgt;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return tgt;

        op_data->op_mds = tgt->ltd_idx;

        return tgt;
}

static int lmv_create(struct obd_export *exp, struct md_op_data *op_data,
                      const void *data, int datalen, int mode, __u32 uid,
                      __u32 gid, cfs_cap_t cap_effective, __u64 rdev,
                      struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        if (!lmv->desc.ld_active_tgt_count)
                return -EIO;

        tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = lmv_fid_alloc(exp, &op_data->op_fid2, op_data);
        if (rc)
                return rc;

        CDEBUG(D_INODE, "CREATE '%*s' on "DFID" -> mds #%x\n",
               op_data->op_namelen, op_data->op_name, PFID(&op_data->op_fid1),
               op_data->op_mds);

        op_data->op_flags |= MF_MDC_CANCEL_FID1;
        rc = md_create(tgt->ltd_exp, op_data, data, datalen, mode, uid, gid,
                       cap_effective, rdev, request);

        if (rc == 0) {
                if (!*request)
                        return rc;
                CDEBUG(D_INODE, "Created - "DFID"\n", PFID(&op_data->op_fid2));
        }
        return rc;
}

static int lmv_done_writing(struct obd_export *exp,
                            struct md_op_data *op_data,
                            struct md_open_data *mod)
{
        struct obd_device     *obd = exp->exp_obd;
        struct lmv_obd  *lmv = &obd->u.lmv;
        struct lmv_tgt_desc   *tgt;
        int                 rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_done_writing(tgt->ltd_exp, op_data, mod);
        return rc;
}

static int
lmv_enqueue_remote(struct obd_export *exp, struct ldlm_enqueue_info *einfo,
                   struct lookup_intent *it, struct md_op_data *op_data,
                   struct lustre_handle *lockh, void *lmm, int lmmsize,
                   __u64 extra_lock_flags)
{
        struct ptlrpc_request      *req = it->d.lustre.it_data;
        struct obd_device         *obd = exp->exp_obd;
        struct lmv_obd       *lmv = &obd->u.lmv;
        struct lustre_handle    plock;
        struct lmv_tgt_desc     *tgt;
        struct md_op_data         *rdata;
        struct lu_fid          fid1;
        struct mdt_body     *body;
        int                      rc = 0;
        int                      pmode;

        body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);

        if (!(body->valid & OBD_MD_MDS))
                return 0;

        CDEBUG(D_INODE, "REMOTE_ENQUEUE '%s' on "DFID" -> "DFID"\n",
               LL_IT2STR(it), PFID(&op_data->op_fid1), PFID(&body->fid1));

        /*
         * We got LOOKUP lock, but we really need attrs.
         */
        pmode = it->d.lustre.it_lock_mode;
        LASSERT(pmode != 0);
        memcpy(&plock, lockh, sizeof(plock));
        it->d.lustre.it_lock_mode = 0;
        it->d.lustre.it_data = NULL;
        fid1 = body->fid1;

        ptlrpc_req_finished(req);

        tgt = lmv_find_target(lmv, &fid1);
        if (IS_ERR(tgt)) {
                rc = PTR_ERR(tgt);
                goto out;
        }

        rdata = kzalloc(sizeof(*rdata), GFP_NOFS);
        if (!rdata) {
                rc = -ENOMEM;
                goto out;
        }

        rdata->op_fid1 = fid1;
        rdata->op_bias = MDS_CROSS_REF;

        rc = md_enqueue(tgt->ltd_exp, einfo, it, rdata, lockh,
                        lmm, lmmsize, NULL, extra_lock_flags);
        kfree(rdata);
out:
        ldlm_lock_decref(&plock, pmode);
        return rc;
}

static int
lmv_enqueue(struct obd_export *exp, struct ldlm_enqueue_info *einfo,
            struct lookup_intent *it, struct md_op_data *op_data,
            struct lustre_handle *lockh, void *lmm, int lmmsize,
            struct ptlrpc_request **req, __u64 extra_lock_flags)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd     *lmv = &obd->u.lmv;
        struct lmv_tgt_desc      *tgt;
        int                    rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        CDEBUG(D_INODE, "ENQUEUE '%s' on "DFID"\n",
               LL_IT2STR(it), PFID(&op_data->op_fid1));

        tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        CDEBUG(D_INODE, "ENQUEUE '%s' on "DFID" -> mds #%d\n",
               LL_IT2STR(it), PFID(&op_data->op_fid1), tgt->ltd_idx);

        rc = md_enqueue(tgt->ltd_exp, einfo, it, op_data, lockh,
                        lmm, lmmsize, req, extra_lock_flags);

        if (rc == 0 && it && it->it_op == IT_OPEN) {
                rc = lmv_enqueue_remote(exp, einfo, it, op_data, lockh,
                                        lmm, lmmsize, extra_lock_flags);
        }
        return rc;
}

static int
lmv_getattr_name(struct obd_export *exp, struct md_op_data *op_data,
                 struct ptlrpc_request **request)
{
        struct ptlrpc_request   *req = NULL;
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        struct mdt_body  *body;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        CDEBUG(D_INODE, "GETATTR_NAME for %*s on "DFID" -> mds #%d\n",
               op_data->op_namelen, op_data->op_name, PFID(&op_data->op_fid1),
               tgt->ltd_idx);

        rc = md_getattr_name(tgt->ltd_exp, op_data, request);
        if (rc != 0)
                return rc;

        body = req_capsule_server_get(&(*request)->rq_pill,
                                      &RMF_MDT_BODY);

        if (body->valid & OBD_MD_MDS) {
                struct lu_fid rid = body->fid1;

                CDEBUG(D_INODE, "Request attrs for "DFID"\n",
                       PFID(&rid));

                tgt = lmv_find_target(lmv, &rid);
                if (IS_ERR(tgt)) {
                        ptlrpc_req_finished(*request);
                        return PTR_ERR(tgt);
                }

                op_data->op_fid1 = rid;
                op_data->op_valid |= OBD_MD_FLCROSSREF;
                op_data->op_namelen = 0;
                op_data->op_name = NULL;
                rc = md_getattr_name(tgt->ltd_exp, op_data, &req);
                ptlrpc_req_finished(*request);
                *request = req;
        }

        return rc;
}

#define md_op_data_fid(op_data, fl)                  \
        (fl == MF_MDC_CANCEL_FID1 ? &op_data->op_fid1 : \
         fl == MF_MDC_CANCEL_FID2 ? &op_data->op_fid2 : \
         fl == MF_MDC_CANCEL_FID3 ? &op_data->op_fid3 : \
         fl == MF_MDC_CANCEL_FID4 ? &op_data->op_fid4 : \
         NULL)

static int lmv_early_cancel(struct obd_export *exp, struct md_op_data *op_data,
                            int op_tgt, enum ldlm_mode mode, int bits,
                            int flag)
{
        struct lu_fid     *fid = md_op_data_fid(op_data, flag);
        struct obd_device      *obd = exp->exp_obd;
        struct lmv_obd   *lmv = &obd->u.lmv;
        struct lmv_tgt_desc    *tgt;
        ldlm_policy_data_t      policy = { {0} };
        int                  rc = 0;

        if (!fid_is_sane(fid))
                return 0;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        if (tgt->ltd_idx != op_tgt) {
                CDEBUG(D_INODE, "EARLY_CANCEL on "DFID"\n", PFID(fid));
                policy.l_inodebits.bits = bits;
                rc = md_cancel_unused(tgt->ltd_exp, fid, &policy,
                                      mode, LCF_ASYNC, NULL);
        } else {
                CDEBUG(D_INODE,
                       "EARLY_CANCEL skip operation target %d on "DFID"\n",
                       op_tgt, PFID(fid));
                op_data->op_flags |= flag;
                rc = 0;
        }

        return rc;
}

/*
 * llite passes fid of an target inode in op_data->op_fid1 and id of directory in
 * op_data->op_fid2
 */
static int lmv_link(struct obd_export *exp, struct md_op_data *op_data,
                    struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        LASSERT(op_data->op_namelen != 0);

        CDEBUG(D_INODE, "LINK "DFID":%*s to "DFID"\n",
               PFID(&op_data->op_fid2), op_data->op_namelen,
               op_data->op_name, PFID(&op_data->op_fid1));

        op_data->op_fsuid = from_kuid(&init_user_ns, current_fsuid());
        op_data->op_fsgid = from_kgid(&init_user_ns, current_fsgid());
        op_data->op_cap = cfs_curproc_cap_pack();
        tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid2);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        /*
         * Cancel UPDATE lock on child (fid1).
         */
        op_data->op_flags |= MF_MDC_CANCEL_FID2;
        rc = lmv_early_cancel(exp, op_data, tgt->ltd_idx, LCK_EX,
                              MDS_INODELOCK_UPDATE, MF_MDC_CANCEL_FID1);
        if (rc != 0)
                return rc;

        rc = md_link(tgt->ltd_exp, op_data, request);

        return rc;
}

static int lmv_rename(struct obd_export *exp, struct md_op_data *op_data,
                      const char *old, int oldlen, const char *new, int newlen,
                      struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *src_tgt;
        struct lmv_tgt_desc     *tgt_tgt;
        int                     rc;

        LASSERT(oldlen != 0);

        CDEBUG(D_INODE, "RENAME %*s in "DFID" to %*s in "DFID"\n",
               oldlen, old, PFID(&op_data->op_fid1),
               newlen, new, PFID(&op_data->op_fid2));

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        op_data->op_fsuid = from_kuid(&init_user_ns, current_fsuid());
        op_data->op_fsgid = from_kgid(&init_user_ns, current_fsgid());
        op_data->op_cap = cfs_curproc_cap_pack();
        src_tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(src_tgt))
                return PTR_ERR(src_tgt);

        tgt_tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid2);
        if (IS_ERR(tgt_tgt))
                return PTR_ERR(tgt_tgt);
        /*
         * LOOKUP lock on src child (fid3) should also be cancelled for
         * src_tgt in mdc_rename.
         */
        op_data->op_flags |= MF_MDC_CANCEL_FID1 | MF_MDC_CANCEL_FID3;

        /*
         * Cancel UPDATE locks on tgt parent (fid2), tgt_tgt is its
         * own target.
         */
        rc = lmv_early_cancel(exp, op_data, src_tgt->ltd_idx,
                              LCK_EX, MDS_INODELOCK_UPDATE,
                              MF_MDC_CANCEL_FID2);

        /*
         * Cancel LOOKUP locks on tgt child (fid4) for parent tgt_tgt.
         */
        if (rc == 0) {
                rc = lmv_early_cancel(exp, op_data, src_tgt->ltd_idx,
                                      LCK_EX, MDS_INODELOCK_LOOKUP,
                                      MF_MDC_CANCEL_FID4);
        }

        /*
         * Cancel all the locks on tgt child (fid4).
         */
        if (rc == 0)
                rc = lmv_early_cancel(exp, op_data, src_tgt->ltd_idx,
                                      LCK_EX, MDS_INODELOCK_FULL,
                                      MF_MDC_CANCEL_FID4);

        if (rc == 0)
                rc = md_rename(src_tgt->ltd_exp, op_data, old, oldlen,
                               new, newlen, request);
        return rc;
}

static int lmv_setattr(struct obd_export *exp, struct md_op_data *op_data,
                       void *ea, int ealen, void *ea2, int ea2len,
                       struct ptlrpc_request **request,
                       struct md_open_data **mod)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        CDEBUG(D_INODE, "SETATTR for "DFID", valid 0x%x\n",
               PFID(&op_data->op_fid1), op_data->op_attr.ia_valid);

        op_data->op_flags |= MF_MDC_CANCEL_FID1;
        tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_setattr(tgt->ltd_exp, op_data, ea, ealen, ea2,
                        ea2len, request, mod);

        return rc;
}

static int lmv_sync(struct obd_export *exp, const struct lu_fid *fid,
                    struct ptlrpc_request **request)
{
        struct obd_device        *obd = exp->exp_obd;
        struct lmv_obd      *lmv = &obd->u.lmv;
        struct lmv_tgt_desc       *tgt;
        int                     rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_sync(tgt->ltd_exp, fid, request);
        return rc;
}

/*
 * Adjust a set of pages, each page containing an array of lu_dirpages,
 * so that each page can be used as a single logical lu_dirpage.
 *
 * A lu_dirpage is laid out as follows, where s = ldp_hash_start,
 * e = ldp_hash_end, f = ldp_flags, p = padding, and each "ent" is a
 * struct lu_dirent.  It has size up to LU_PAGE_SIZE. The ldp_hash_end
 * value is used as a cookie to request the next lu_dirpage in a
 * directory listing that spans multiple pages (two in this example):
 *   ________
 *  |   |
 * .|--------v-------   -----.
 * |s|e|f|p|ent|ent| ... |ent|
 * '--|--------------   -----'   Each CFS_PAGE contains a single
 *    '------.             lu_dirpage.
 * .---------v-------   -----.
 * |s|e|f|p|ent| 0 | ... | 0 |
 * '-----------------   -----'
 *
 * However, on hosts where the native VM page size (PAGE_SIZE) is
 * larger than LU_PAGE_SIZE, a single host page may contain multiple
 * lu_dirpages. After reading the lu_dirpages from the MDS, the
 * ldp_hash_end of the first lu_dirpage refers to the one immediately
 * after it in the same CFS_PAGE (arrows simplified for brevity, but
 * in general e0==s1, e1==s2, etc.):
 *
 * .--------------------   -----.
 * |s0|e0|f0|p|ent|ent| ... |ent|
 * |---v----------------   -----|
 * |s1|e1|f1|p|ent|ent| ... |ent|
 * |---v----------------   -----|  Here, each CFS_PAGE contains
 *           ...                 multiple lu_dirpages.
 * |---v----------------   -----|
 * |s'|e'|f'|p|ent|ent| ... |ent|
 * '---|----------------   -----'
 *     v
 * .----------------------------.
 * |    next CFS_PAGE       |
 *
 * This structure is transformed into a single logical lu_dirpage as follows:
 *
 * - Replace e0 with e' so the request for the next lu_dirpage gets the page
 *   labeled 'next CFS_PAGE'.
 *
 * - Copy the LDF_COLLIDE flag from f' to f0 to correctly reflect whether
 *   a hash collision with the next page exists.
 *
 * - Adjust the lde_reclen of the ending entry of each lu_dirpage to span
 *   to the first entry of the next lu_dirpage.
 */
#if PAGE_SIZE > LU_PAGE_SIZE
static void lmv_adjust_dirpages(struct page **pages, int ncfspgs, int nlupgs)
{
        int i;

        for (i = 0; i < ncfspgs; i++) {
                struct lu_dirpage       *dp = kmap(pages[i]);
                struct lu_dirpage       *first = dp;
                struct lu_dirent        *end_dirent = NULL;
                struct lu_dirent        *ent;
                __u64                   hash_end = dp->ldp_hash_end;
                __u32                   flags = dp->ldp_flags;

                while (--nlupgs > 0) {
                        ent = lu_dirent_start(dp);
                        for (end_dirent = ent; ent;
                             end_dirent = ent, ent = lu_dirent_next(ent))
                                ;

                        /* Advance dp to next lu_dirpage. */
                        dp = (struct lu_dirpage *)((char *)dp + LU_PAGE_SIZE);

                        /* Check if we've reached the end of the CFS_PAGE. */
                        if (!((unsigned long)dp & ~CFS_PAGE_MASK))
                                break;

                        /* Save the hash and flags of this lu_dirpage. */
                        hash_end = dp->ldp_hash_end;
                        flags = dp->ldp_flags;

                        /* Check if lu_dirpage contains no entries. */
                        if (!end_dirent)
                                break;

                        /* Enlarge the end entry lde_reclen from 0 to
                         * first entry of next lu_dirpage.
                         */
                        LASSERT(le16_to_cpu(end_dirent->lde_reclen) == 0);
                        end_dirent->lde_reclen =
                                cpu_to_le16((char *)(dp->ldp_entries) -
                                            (char *)end_dirent);
                }

                first->ldp_hash_end = hash_end;
                first->ldp_flags &= ~cpu_to_le32(LDF_COLLIDE);
                first->ldp_flags |= flags & cpu_to_le32(LDF_COLLIDE);

                kunmap(pages[i]);
        }
        LASSERTF(nlupgs == 0, "left = %d", nlupgs);
}
#else
#define lmv_adjust_dirpages(pages, ncfspgs, nlupgs) do {} while (0)
#endif  /* PAGE_SIZE > LU_PAGE_SIZE */

static int lmv_readpage(struct obd_export *exp, struct md_op_data *op_data,
                        struct page **pages, struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd          *lmv = &obd->u.lmv;
        __u64                   offset = op_data->op_offset;
        int                     rc;
        int                     ncfspgs; /* pages read in PAGE_SIZE */
        int                     nlupgs; /* pages read in LU_PAGE_SIZE */
        struct lmv_tgt_desc     *tgt;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        CDEBUG(D_INODE, "READPAGE at %#llx from "DFID"\n",
               offset, PFID(&op_data->op_fid1));

        tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_readpage(tgt->ltd_exp, op_data, pages, request);
        if (rc != 0)
                return rc;

        ncfspgs = ((*request)->rq_bulk->bd_nob_transferred + PAGE_SIZE - 1)
                 >> PAGE_SHIFT;
        nlupgs = (*request)->rq_bulk->bd_nob_transferred >> LU_PAGE_SHIFT;
        LASSERT(!((*request)->rq_bulk->bd_nob_transferred & ~LU_PAGE_MASK));
        LASSERT(ncfspgs > 0 && ncfspgs <= op_data->op_npages);

        CDEBUG(D_INODE, "read %d(%d)/%d pages\n", ncfspgs, nlupgs,
               op_data->op_npages);

        lmv_adjust_dirpages(pages, ncfspgs, nlupgs);

        return rc;
}

static int lmv_unlink(struct obd_export *exp, struct md_op_data *op_data,
                      struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt = NULL;
        struct mdt_body         *body;
        int                  rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;
retry:
        /* Send unlink requests to the MDT where the child is located */
        if (likely(!fid_is_zero(&op_data->op_fid2)))
                tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid2);
        else
                tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        op_data->op_fsuid = from_kuid(&init_user_ns, current_fsuid());
        op_data->op_fsgid = from_kgid(&init_user_ns, current_fsgid());
        op_data->op_cap = cfs_curproc_cap_pack();

        /*
         * If child's fid is given, cancel unused locks for it if it is from
         * another export than parent.
         *
         * LOOKUP lock for child (fid3) should also be cancelled on parent
         * tgt_tgt in mdc_unlink().
         */
        op_data->op_flags |= MF_MDC_CANCEL_FID1 | MF_MDC_CANCEL_FID3;

        /*
         * Cancel FULL locks on child (fid3).
         */
        rc = lmv_early_cancel(exp, op_data, tgt->ltd_idx, LCK_EX,
                              MDS_INODELOCK_FULL, MF_MDC_CANCEL_FID3);

        if (rc != 0)
                return rc;

        CDEBUG(D_INODE, "unlink with fid="DFID"/"DFID" -> mds #%d\n",
               PFID(&op_data->op_fid1), PFID(&op_data->op_fid2), tgt->ltd_idx);

        rc = md_unlink(tgt->ltd_exp, op_data, request);
        if (rc != 0 && rc != -EREMOTE)
                return rc;

        body = req_capsule_server_get(&(*request)->rq_pill, &RMF_MDT_BODY);
        if (!body)
                return -EPROTO;

        /* Not cross-ref case, just get out of here. */
        if (likely(!(body->valid & OBD_MD_MDS)))
                return 0;

        CDEBUG(D_INODE, "%s: try unlink to another MDT for "DFID"\n",
               exp->exp_obd->obd_name, PFID(&body->fid1));

        /* This is a remote object, try remote MDT, Note: it may
         * try more than 1 time here, Considering following case
         * /mnt/lustre is root on MDT0, remote1 is on MDT1
         * 1. Initially A does not know where remote1 is, it send
         *    unlink RPC to MDT0, MDT0 return -EREMOTE, it will
         *    resend unlink RPC to MDT1 (retry 1st time).
         *
         * 2. During the unlink RPC in flight,
         *    client B mv /mnt/lustre/remote1 /mnt/lustre/remote2
         *    and create new remote1, but on MDT0
         *
         * 3. MDT1 get unlink RPC(from A), then do remote lock on
         *    /mnt/lustre, then lookup get fid of remote1, and find
         *    it is remote dir again, and replay -EREMOTE again.
         *
         * 4. Then A will resend unlink RPC to MDT0. (retry 2nd times).
         *
         * In theory, it might try unlimited time here, but it should
         * be very rare case.
         */
        op_data->op_fid2 = body->fid1;
        ptlrpc_req_finished(*request);
        *request = NULL;

        goto retry;
}

static int lmv_precleanup(struct obd_device *obd, enum obd_cleanup_stage stage)
{
        struct lmv_obd *lmv = &obd->u.lmv;

        switch (stage) {
        case OBD_CLEANUP_EARLY:
                /* XXX: here should be calling obd_precleanup() down to
                 * stack.
                 */
                break;
        case OBD_CLEANUP_EXPORTS:
                fld_client_debugfs_fini(&lmv->lmv_fld);
                lprocfs_obd_cleanup(obd);
                break;
        default:
                break;
        }
        return 0;
}

static int lmv_get_info(const struct lu_env *env, struct obd_export *exp,
                        __u32 keylen, void *key, __u32 *vallen, void *val,
                        struct lov_stripe_md *lsm)
{
        struct obd_device       *obd;
        struct lmv_obd    *lmv;
        int                   rc = 0;

        obd = class_exp2obd(exp);
        if (!obd) {
                CDEBUG(D_IOCTL, "Invalid client cookie %#llx\n",
                       exp->exp_handle.h_cookie);
                return -EINVAL;
        }

        lmv = &obd->u.lmv;
        if (keylen >= strlen("remote_flag") && !strcmp(key, "remote_flag")) {
                struct lmv_tgt_desc *tgt;
                int i;

                rc = lmv_check_connect(obd);
                if (rc)
                        return rc;

                LASSERT(*vallen == sizeof(__u32));
                for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                        tgt = lmv->tgts[i];
                        /*
                         * All tgts should be connected when this gets called.
                         */
                        if (!tgt || !tgt->ltd_exp)
                                continue;

                        if (!obd_get_info(env, tgt->ltd_exp, keylen, key,
                                          vallen, val, NULL))
                                return 0;
                }
                return -EINVAL;
        } else if (KEY_IS(KEY_MAX_EASIZE) ||
                   KEY_IS(KEY_DEFAULT_EASIZE) ||
                   KEY_IS(KEY_CONN_DATA)) {
                rc = lmv_check_connect(obd);
                if (rc)
                        return rc;

                /*
                 * Forwarding this request to first MDS, it should know LOV
                 * desc.
                 */
                rc = obd_get_info(env, lmv->tgts[0]->ltd_exp, keylen, key,
                                  vallen, val, NULL);
                if (!rc && KEY_IS(KEY_CONN_DATA))
                        exp->exp_connect_data = *(struct obd_connect_data *)val;
                return rc;
        } else if (KEY_IS(KEY_TGT_COUNT)) {
                *((int *)val) = lmv->desc.ld_tgt_count;
                return 0;
        }

        CDEBUG(D_IOCTL, "Invalid key\n");
        return -EINVAL;
}

static int lmv_set_info_async(const struct lu_env *env, struct obd_export *exp,
                              u32 keylen, void *key, u32 vallen,
                              void *val, struct ptlrpc_request_set *set)
{
        struct lmv_tgt_desc    *tgt;
        struct obd_device      *obd;
        struct lmv_obd   *lmv;
        int rc = 0;

        obd = class_exp2obd(exp);
        if (!obd) {
                CDEBUG(D_IOCTL, "Invalid client cookie %#llx\n",
                       exp->exp_handle.h_cookie);
                return -EINVAL;
        }
        lmv = &obd->u.lmv;

        if (KEY_IS(KEY_READ_ONLY) || KEY_IS(KEY_FLUSH_CTX)) {
                int i, err = 0;

                for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                        tgt = lmv->tgts[i];

                        if (!tgt || !tgt->ltd_exp)
                                continue;

                        err = obd_set_info_async(env, tgt->ltd_exp,
                                                 keylen, key, vallen, val, set);
                        if (err && rc == 0)
                                rc = err;
                }

                return rc;
        }

        return -EINVAL;
}

static int lmv_packmd(struct obd_export *exp, struct lov_mds_md **lmmp,
                      struct lov_stripe_md *lsm)
{
        struct obd_device        *obd = class_exp2obd(exp);
        struct lmv_obd      *lmv = &obd->u.lmv;
        struct lmv_stripe_md      *meap;
        struct lmv_stripe_md      *lsmp;
        int                     mea_size;
        int                     i;

        mea_size = lmv_get_easize(lmv);
        if (!lmmp)
                return mea_size;

        if (*lmmp && !lsm) {
                kvfree(*lmmp);
                *lmmp = NULL;
                return 0;
        }

        if (!*lmmp) {
                *lmmp = libcfs_kvzalloc(mea_size, GFP_NOFS);
                if (!*lmmp)
                        return -ENOMEM;
        }

        if (!lsm)
                return mea_size;

        lsmp = (struct lmv_stripe_md *)lsm;
        meap = (struct lmv_stripe_md *)*lmmp;

        if (lsmp->mea_magic != MEA_MAGIC_LAST_CHAR &&
            lsmp->mea_magic != MEA_MAGIC_ALL_CHARS)
                return -EINVAL;

        meap->mea_magic = cpu_to_le32(lsmp->mea_magic);
        meap->mea_count = cpu_to_le32(lsmp->mea_count);
        meap->mea_master = cpu_to_le32(lsmp->mea_master);

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                meap->mea_ids[i] = lsmp->mea_ids[i];
                fid_cpu_to_le(&meap->mea_ids[i], &lsmp->mea_ids[i]);
        }

        return mea_size;
}

static int lmv_unpackmd(struct obd_export *exp, struct lov_stripe_md **lsmp,
                        struct lov_mds_md *lmm, int lmm_size)
{
        struct obd_device         *obd = class_exp2obd(exp);
        struct lmv_stripe_md      **tmea = (struct lmv_stripe_md **)lsmp;
        struct lmv_stripe_md       *mea = (struct lmv_stripe_md *)lmm;
        struct lmv_obd       *lmv = &obd->u.lmv;
        int                      mea_size;
        int                      i;
        __u32                  magic;

        mea_size = lmv_get_easize(lmv);
        if (!lsmp)
                return mea_size;

        if (*lsmp && !lmm) {
                kvfree(*tmea);
                *lsmp = NULL;
                return 0;
        }

        LASSERT(mea_size == lmm_size);

        *tmea = libcfs_kvzalloc(mea_size, GFP_NOFS);
        if (!*tmea)
                return -ENOMEM;

        if (!lmm)
                return mea_size;

        if (mea->mea_magic == MEA_MAGIC_LAST_CHAR ||
            mea->mea_magic == MEA_MAGIC_ALL_CHARS ||
            mea->mea_magic == MEA_MAGIC_HASH_SEGMENT) {
                magic = le32_to_cpu(mea->mea_magic);
        } else {
                /*
                 * Old mea is not handled here.
                 */
                CERROR("Old not supportable EA is found\n");
                LBUG();
        }

        (*tmea)->mea_magic = magic;
        (*tmea)->mea_count = le32_to_cpu(mea->mea_count);
        (*tmea)->mea_master = le32_to_cpu(mea->mea_master);

        for (i = 0; i < (*tmea)->mea_count; i++) {
                (*tmea)->mea_ids[i] = mea->mea_ids[i];
                fid_le_to_cpu(&(*tmea)->mea_ids[i], &(*tmea)->mea_ids[i]);
        }
        return mea_size;
}

static int lmv_cancel_unused(struct obd_export *exp, const struct lu_fid *fid,
                             ldlm_policy_data_t *policy, enum ldlm_mode mode,
                             enum ldlm_cancel_flags flags, void *opaque)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        int                   rc = 0;
        int                   err;
        int                   i;

        LASSERT(fid);

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp ||
                    lmv->tgts[i]->ltd_active == 0)
                        continue;

                err = md_cancel_unused(lmv->tgts[i]->ltd_exp, fid,
                                       policy, mode, flags, opaque);
                if (!rc)
                        rc = err;
        }
        return rc;
}

static int lmv_set_lock_data(struct obd_export *exp, __u64 *lockh, void *data,
                             __u64 *bits)
{
        struct lmv_obd    *lmv = &exp->exp_obd->u.lmv;
        int                   rc;

        rc =  md_set_lock_data(lmv->tgts[0]->ltd_exp, lockh, data, bits);
        return rc;
}

static enum ldlm_mode lmv_lock_match(struct obd_export *exp, __u64 flags,
                                     const struct lu_fid *fid,
                                     enum ldlm_type type,
                                     ldlm_policy_data_t *policy,
                                     enum ldlm_mode mode,
                                     struct lustre_handle *lockh)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        enum ldlm_mode        rc;
        int                   i;

        CDEBUG(D_INODE, "Lock match for "DFID"\n", PFID(fid));

        /*
         * With CMD every object can have two locks in different namespaces:
         * lookup lock in space of mds storing direntry and update/open lock in
         * space of mds storing inode. Thus we check all targets, not only that
         * one fid was created in.
         */
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                if (!lmv->tgts[i] || !lmv->tgts[i]->ltd_exp ||
                    lmv->tgts[i]->ltd_active == 0)
                        continue;

                rc = md_lock_match(lmv->tgts[i]->ltd_exp, flags, fid,
                                   type, policy, mode, lockh);
                if (rc)
                        return rc;
        }

        return 0;
}

static int lmv_get_lustre_md(struct obd_export *exp,
                             struct ptlrpc_request *req,
                             struct obd_export *dt_exp,
                             struct obd_export *md_exp,
                             struct lustre_md *md)
{
        struct lmv_obd    *lmv = &exp->exp_obd->u.lmv;

        return md_get_lustre_md(lmv->tgts[0]->ltd_exp, req, dt_exp, md_exp, md);
}

static int lmv_free_lustre_md(struct obd_export *exp, struct lustre_md *md)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;

        if (md->mea)
                obd_free_memmd(exp, (void *)&md->mea);
        return md_free_lustre_md(lmv->tgts[0]->ltd_exp, md);
}

static int lmv_set_open_replay_data(struct obd_export *exp,
                                    struct obd_client_handle *och,
                                    struct lookup_intent *it)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;

        tgt = lmv_find_target(lmv, &och->och_fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        return md_set_open_replay_data(tgt->ltd_exp, och, it);
}

static int lmv_clear_open_replay_data(struct obd_export *exp,
                                      struct obd_client_handle *och)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;

        tgt = lmv_find_target(lmv, &och->och_fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        return md_clear_open_replay_data(tgt->ltd_exp, och);
}

static int lmv_get_remote_perm(struct obd_export *exp,
                               const struct lu_fid *fid,
                               __u32 suppgid, struct ptlrpc_request **request)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_get_remote_perm(tgt->ltd_exp, fid, suppgid, request);
        return rc;
}

static int lmv_intent_getattr_async(struct obd_export *exp,
                                    struct md_enqueue_info *minfo,
                                    struct ldlm_enqueue_info *einfo)
{
        struct md_op_data       *op_data = &minfo->mi_data;
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt = NULL;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_intent_getattr_async(tgt->ltd_exp, minfo, einfo);
        return rc;
}

static int lmv_revalidate_lock(struct obd_export *exp, struct lookup_intent *it,
                               struct lu_fid *fid, __u64 *bits)
{
        struct obd_device       *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc     *tgt;
        int                   rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;

        tgt = lmv_find_target(lmv, fid);
        if (IS_ERR(tgt))
                return PTR_ERR(tgt);

        rc = md_revalidate_lock(tgt->ltd_exp, it, fid, bits);
        return rc;
}

/**
 * For lmv, only need to send request to master MDT, and the master MDT will
 * process with other slave MDTs. The only exception is Q_GETOQUOTA for which
 * we directly fetch data from the slave MDTs.
 */
static int lmv_quotactl(struct obd_device *unused, struct obd_export *exp,
                        struct obd_quotactl *oqctl)
{
        struct obd_device   *obd = class_exp2obd(exp);
        struct lmv_obd      *lmv = &obd->u.lmv;
        struct lmv_tgt_desc *tgt = lmv->tgts[0];
        int               rc = 0, i;
        __u64           curspace, curinodes;

        if (!lmv->desc.ld_tgt_count || !tgt->ltd_active) {
                CERROR("master lmv inactive\n");
                return -EIO;
        }

        if (oqctl->qc_cmd != Q_GETOQUOTA) {
                rc = obd_quotactl(tgt->ltd_exp, oqctl);
                return rc;
        }

        curspace = curinodes = 0;
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                int err;

                tgt = lmv->tgts[i];

                if (!tgt || !tgt->ltd_exp || tgt->ltd_active == 0)
                        continue;
                if (!tgt->ltd_active) {
                        CDEBUG(D_HA, "mdt %d is inactive.\n", i);
                        continue;
                }

                err = obd_quotactl(tgt->ltd_exp, oqctl);
                if (err) {
                        CERROR("getquota on mdt %d failed. %d\n", i, err);
                        if (!rc)
                                rc = err;
                } else {
                        curspace += oqctl->qc_dqblk.dqb_curspace;
                        curinodes += oqctl->qc_dqblk.dqb_curinodes;
                }
        }
        oqctl->qc_dqblk.dqb_curspace = curspace;
        oqctl->qc_dqblk.dqb_curinodes = curinodes;

        return rc;
}

static int lmv_quotacheck(struct obd_device *unused, struct obd_export *exp,
                          struct obd_quotactl *oqctl)
{
        struct obd_device   *obd = class_exp2obd(exp);
        struct lmv_obd      *lmv = &obd->u.lmv;
        struct lmv_tgt_desc *tgt;
        int               i, rc = 0;

        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                int err;

                tgt = lmv->tgts[i];
                if (!tgt || !tgt->ltd_exp || !tgt->ltd_active) {
                        CERROR("lmv idx %d inactive\n", i);
                        return -EIO;
                }

                err = obd_quotacheck(tgt->ltd_exp, oqctl);
                if (err && !rc)
                        rc = err;
        }

        return rc;
}

static struct obd_ops lmv_obd_ops = {
        .owner          = THIS_MODULE,
        .setup          = lmv_setup,
        .cleanup        = lmv_cleanup,
        .precleanup     = lmv_precleanup,
        .process_config = lmv_process_config,
        .connect        = lmv_connect,
        .disconnect     = lmv_disconnect,
        .statfs         = lmv_statfs,
        .get_info       = lmv_get_info,
        .set_info_async = lmv_set_info_async,
        .packmd         = lmv_packmd,
        .unpackmd       = lmv_unpackmd,
        .notify         = lmv_notify,
        .get_uuid       = lmv_get_uuid,
        .iocontrol      = lmv_iocontrol,
        .quotacheck     = lmv_quotacheck,
        .quotactl       = lmv_quotactl
};

static struct md_ops lmv_md_ops = {
        .getstatus              = lmv_getstatus,
        .null_inode             = lmv_null_inode,
        .find_cbdata            = lmv_find_cbdata,
        .close                  = lmv_close,
        .create                 = lmv_create,
        .done_writing           = lmv_done_writing,
        .enqueue                = lmv_enqueue,
        .getattr                = lmv_getattr,
        .getxattr               = lmv_getxattr,
        .getattr_name           = lmv_getattr_name,
        .intent_lock            = lmv_intent_lock,
        .link                   = lmv_link,
        .rename                 = lmv_rename,
        .setattr                = lmv_setattr,
        .setxattr               = lmv_setxattr,
        .sync                   = lmv_sync,
        .readpage               = lmv_readpage,
        .unlink                 = lmv_unlink,
        .init_ea_size           = lmv_init_ea_size,
        .cancel_unused          = lmv_cancel_unused,
        .set_lock_data          = lmv_set_lock_data,
        .lock_match             = lmv_lock_match,
        .get_lustre_md          = lmv_get_lustre_md,
        .free_lustre_md         = lmv_free_lustre_md,
        .set_open_replay_data   = lmv_set_open_replay_data,
        .clear_open_replay_data = lmv_clear_open_replay_data,
        .get_remote_perm        = lmv_get_remote_perm,
        .intent_getattr_async   = lmv_intent_getattr_async,
        .revalidate_lock        = lmv_revalidate_lock
};

static int __init lmv_init(void)
{
        struct lprocfs_static_vars lvars;
        int                     rc;

        lprocfs_lmv_init_vars(&lvars);

        rc = class_register_type(&lmv_obd_ops, &lmv_md_ops,
                                 LUSTRE_LMV_NAME, NULL);
        return rc;
}

static void lmv_exit(void)
{
        class_unregister_type(LUSTRE_LMV_NAME);
}

MODULE_AUTHOR("OpenSFS, Inc. <http://www.lustre.org/>");
MODULE_DESCRIPTION("Lustre Logical Metadata Volume");
MODULE_VERSION(LUSTRE_VERSION_STRING);
MODULE_LICENSE("GPL");

module_init(lmv_init);
module_exit(lmv_exit);