iio: imu: inv_mpu6050: test whoami first and against all known values

[mirror_ubuntu-artful-kernel.git] / drivers / staging / lustre / lustre / lmv / lmv_obd.c

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * 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_net.h"
#include "../include/obd_class.h"
#include "../include/lustre_lmv.h"
#include "../include/lprocfs_status.h"
#include "../include/cl_object.h"
#include "../include/lustre_fid.h"
#include "../include/lustre/lustre_ioctl.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);
        tgt->ltd_exp->exp_obd->obd_inactive = !activate;
}

/**
 * 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, const struct obd_uuid *uuid,
                              int activate)
{
        struct lmv_tgt_desc    *uninitialized_var(tgt);
        struct obd_device      *obd;
        u32                  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;
        struct lmv_tgt_desc *tgt = lmv->tgts[0];

        return tgt ? obd_get_uuid(tgt->ltd_exp) : NULL;
}

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;
        }

        /*
         * 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 int lmv_init_ea_size(struct obd_export *exp, u32 easize, u32 def_easize)
{
        struct obd_device   *obd = exp->exp_obd;
        struct lmv_obd      *lmv = &obd->u.lmv;
        u32 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 (change == 0)
                return 0;

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

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

                if (!tgt || !tgt->ltd_exp || !tgt->ltd_active) {
                        CWARN("%s: NULL export for %d\n", obd->obd_name, i);
                        continue;
                }

                rc = md_init_ea_size(tgt->ltd_exp, easize, def_easize);
                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);

        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;
}

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 obd_device *mdc_obd;
        struct lmv_tgt_desc *tgt;
        int orig_tgt_count = 0;
        int               rc = 0;

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

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

        mutex_lock(&lmv->lmv_init_mutex);

        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);
                mutex_unlock(&lmv->lmv_init_mutex);
                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) {
                        mutex_unlock(&lmv->lmv_init_mutex);
                        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) {
                mutex_unlock(&lmv->lmv_init_mutex);
                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) {
                orig_tgt_count = lmv->desc.ld_tgt_count;
                lmv->desc.ld_tgt_count = index + 1;
        }

        if (!lmv->connected) {
                /* lmv_check_connect() will connect this target. */
                mutex_unlock(&lmv->lmv_init_mutex);
                return rc;
        }

        /* Otherwise let's connect it ourselves */
        mutex_unlock(&lmv->lmv_init_mutex);
        rc = lmv_connect_mdc(obd, tgt);
        if (rc) {
                spin_lock(&lmv->lmv_lock);
                if (lmv->desc.ld_tgt_count == index + 1)
                        lmv->desc.ld_tgt_count = orig_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);
        }

        return rc;
}

int lmv_check_connect(struct obd_device *obd)
{
        struct lmv_obd       *lmv = &obd->u.lmv;
        struct lmv_tgt_desc  *tgt;
        u32 i;
        int                rc;
        int                easize;

        if (lmv->connected)
                return 0;

        mutex_lock(&lmv->lmv_init_mutex);
        if (lmv->connected) {
                mutex_unlock(&lmv->lmv_init_mutex);
                return 0;
        }

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

        LASSERT(lmv->tgts);

        if (!lmv->tgts[0]) {
                mutex_unlock(&lmv->lmv_init_mutex);
                CERROR("%s: no target configured for index 0.\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;
        }

        class_export_put(lmv->exp);
        lmv->connected = 1;
        easize = lmv_mds_md_size(lmv->desc.ld_tgt_count, LMV_MAGIC);
        lmv_init_ea_size(obd->obd_self_export, easize, 0);
        mutex_unlock(&lmv->lmv_init_mutex);
        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);
        mutex_unlock(&lmv->lmv_init_mutex);
        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;
        u32 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 = 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 = 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)
{
        u32 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 (IS_ERR(curr_tgt))
                        return PTR_ERR(curr_tgt);
                if (obd_uuid_equals(&curr_tgt->ltd_uuid, &tgt_mds->ltd_uuid))
                        nr++;
        }
        return nr;
}

static int 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 (IS_ERR(curr_tgt))
                        return PTR_ERR(curr_tgt);
                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);

        return 0;
}

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

        /* unregister request (call from llapi_hsm_copytool_fini) */
        for (i = 0; i < lmv->desc.ld_tgt_count; i++) {
                struct lmv_tgt_desc *tgt = lmv->tgts[i];

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

                /* 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.
         */
        return libcfs_kkuc_group_rem(lk->lk_uid, lk->lk_group);
}

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++) {
                struct lmv_tgt_desc *tgt = lmv->tgts[i];

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

                err = obd_iocontrol(cmd, tgt->ltd_exp, len, lk, uarg);
                if (err) {
                        if (tgt->ltd_active) {
                                /* permanent error */
                                CERROR("error: iocontrol MDC %s on MDTidx %d cmd %x: err = %d\n",
                                       tgt->ltd_uuid.uuid, i, cmd, err);
                                rc = err;
                                lk->lk_flags |= LK_FLG_STOP;
                                /* unregister from previous MDS */
                                for (j = 0; j < i; j++) {
                                        tgt = lmv->tgts[j];

                                        if (!tgt || !tgt->ltd_exp)
                                                continue;
                                        obd_iocontrol(cmd, tgt->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)
                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;
        struct lmv_tgt_desc *tgt = NULL;
        u32 i = 0;
        int                rc = 0;
        int                set = 0;
        u32 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;

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

                mdc_obd = class_exp2obd(tgt->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, tgt->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 obd_quotactl *oqctl;

                if (qctl->qc_valid == QC_MDTIDX) {
                        if (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;

                tgt = lmv->tgts[icc->icc_mdtindex];
                if (!tgt || !tgt->ltd_exp || !tgt->ltd_active)
                        return -ENODEV;
                rc = obd_iocontrol(cmd, tgt->ltd_exp, sizeof(*icc), icc, NULL);
                break;
        }
        case LL_IOC_GET_CONNECT_FLAGS: {
                tgt = lmv->tgts[0];

                if (!tgt || !tgt->ltd_exp)
                        return -ENODATA;
                rc = obd_iocontrol(cmd, tgt->ltd_exp, len, karg, uarg);
                break;
        }
        case LL_IOC_FID2MDTIDX: {
                struct lu_fid *fid = karg;
                int mdt_index;

                rc = lmv_fld_lookup(lmv, fid, &mdt_index);
                if (rc)
                        return rc;

                /*
                 * Note: this is from llite(see ll_dir_ioctl()), @uarg does not
                 * point to user space memory for FID2MDTIDX.
                 */
                *(__u32 *)uarg = mdt_index;
                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;

                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;

                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;
                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++) {
                                struct hsm_user_request *req;
                                size_t reqlen;
                                int nr, rc1;

                                tgt = lmv->tgts[i];
                                if (!tgt || !tgt->ltd_exp)
                                        continue;

                                nr = lmv_hsm_req_count(lmv, hur, tgt);
                                if (nr < 0)
                                        return nr;
                                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;

                                rc1 = lmv_hsm_req_build(lmv, hur, tgt, req);
                                if (rc1 < 0)
                                        goto hsm_req_err;

                                rc1 = obd_iocontrol(cmd, tgt->ltd_exp, reqlen,
                                                    req, uarg);
hsm_req_err:
                                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;

                        tgt = lmv->tgts[i];
                        if (!tgt || !tgt->ltd_exp)
                                continue;
                        /* ll_umount_begin() sets force flag but for lmv, not
                         * mdc. Let's pass it through
                         */
                        mdc_obd = class_exp2obd(tgt->ltd_exp);
                        mdc_obd->obd_force = obddev->obd_force;
                        err = obd_iocontrol(cmd, tgt->ltd_exp, len, karg, uarg);
                        if (err) {
                                if (tgt->ltd_active) {
                                        CERROR("error: iocontrol MDC %s on MDTidx %d cmd %x: err = %d\n",
                                               tgt->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 (op_data->op_default_stripe_offset != -1) {
                *mds = op_data->op_default_stripe_offset;
                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 && op_data->op_data) {
                struct lmv_user_md *lum;

                lum = op_data->op_data;
                if (le32_to_cpu(lum->lum_stripe_offset) != (__u32)-1) {
                        *mds = le32_to_cpu(lum->lum_stripe_offset);
                } else {
                        /*
                         * -1 means default, which will be in the same MDT with
                         * the stripe
                         */
                        *mds = op_data->op_mds;
                        lum->lum_stripe_offset = cpu_to_le32(op_data->op_mds);
                }
        } else {
                /*
                 * 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, NULL);
        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(NULL, 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(const struct lu_env *env, 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_size = 32U;
        lmv->tgts = kcalloc(lmv->tgts_size, sizeof(*lmv->tgts), GFP_NOFS);
        if (!lmv->tgts)
                return -ENOMEM;

        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_def_easize = 0;
        lmv->max_easize = 0;

        spin_lock_init(&lmv->lmv_lock);
        mutex_init(&lmv->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), "%u", &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;
        u32 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;

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

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);

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

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);

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

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;
        }

        return md_getattr(tgt->ltd_exp, op_data, request);
}

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;
        u32 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_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));
        return md_close(tgt->ltd_exp, op_data, mod, request);
}

/**
 * Choosing the MDT by name or FID in @op_data.
 * For non-striped directory, it will locate MDT by fid.
 * For striped-directory, it will locate MDT by name. And also
 * it will reset op_fid1 with the FID of the chosen stripe.
 **/
static struct lmv_tgt_desc *
lmv_locate_target_for_name(struct lmv_obd *lmv, struct lmv_stripe_md *lsm,
                           const char *name, int namelen, struct lu_fid *fid,
                           u32 *mds)
{
        const struct lmv_oinfo *oinfo;
        struct lmv_tgt_desc *tgt;

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_NAME_HASH)) {
                if (cfs_fail_val >= lsm->lsm_md_stripe_count)
                        return ERR_PTR(-EBADF);
                oinfo = &lsm->lsm_md_oinfo[cfs_fail_val];
        } else {
                oinfo = lsm_name_to_stripe_info(lsm, name, namelen);
                if (IS_ERR(oinfo))
                        return ERR_CAST(oinfo);
        }

        if (fid)
                *fid = oinfo->lmo_fid;
        if (mds)
                *mds = oinfo->lmo_mds;

        tgt = lmv_get_target(lmv, oinfo->lmo_mds, NULL);

        CDEBUG(D_INFO, "locate on mds %u " DFID "\n", oinfo->lmo_mds,
               PFID(&oinfo->lmo_fid));
        return tgt;
}

/**
 * Locate mds by fid or name
 *
 * For striped directory (lsm != NULL), it will locate the stripe
 * by name hash (see lsm_name_to_stripe_info()). Note: if the hash_type
 * is unknown, it will return -EBADFD, and lmv_intent_lookup might need
 * walk through all of stripes to locate the entry.
 *
 * For normal direcotry, it will locate MDS by FID directly.
 * \param[in] lmv       LMV device
 * \param[in] op_data   client MD stack parameters, name, namelen
 *                      mds_num etc.
 * \param[in] fid       object FID used to locate MDS.
 *
 * retval               pointer to the lmv_tgt_desc if succeed.
 *                      ERR_PTR(errno) if failed.
 */
struct lmv_tgt_desc*
lmv_locate_mds(struct lmv_obd *lmv, struct md_op_data *op_data,
               struct lu_fid *fid)
{
        struct lmv_stripe_md *lsm = op_data->op_mea1;
        struct lmv_tgt_desc *tgt;

        /*
         * During creating VOLATILE file, it should honor the mdt
         * index if the file under striped dir is being restored, see
         * ct_restore().
         */
        if (op_data->op_bias & MDS_CREATE_VOLATILE &&
            (int)op_data->op_mds != -1) {
                int i;

                tgt = lmv_get_target(lmv, op_data->op_mds, NULL);
                if (IS_ERR(tgt))
                        return tgt;

                if (lsm) {
                        /* refill the right parent fid */
                        for (i = 0; i < lsm->lsm_md_stripe_count; i++) {
                                struct lmv_oinfo *oinfo;

                                oinfo = &lsm->lsm_md_oinfo[i];
                                if (oinfo->lmo_mds == op_data->op_mds) {
                                        *fid = oinfo->lmo_fid;
                                        break;
                                }
                        }

                        if (i == lsm->lsm_md_stripe_count)
                                *fid = lsm->lsm_md_oinfo[0].lmo_fid;
                }

                return tgt;
        }

        if (!lsm || !op_data->op_namelen) {
                tgt = lmv_find_target(lmv, fid);
                if (IS_ERR(tgt))
                        return tgt;

                op_data->op_mds = tgt->ltd_idx;

                return tgt;
        }

        return lmv_locate_target_for_name(lmv, lsm, op_data->op_name,
                                          op_data->op_namelen, fid,
                                          &op_data->op_mds);
}

static int lmv_create(struct obd_export *exp, struct md_op_data *op_data,
                      const void *data, size_t datalen, umode_t mode,
                      uid_t uid, gid_t 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);

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

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

        if (exp_connect_flags(exp) & OBD_CONNECT_DIR_STRIPE) {
                /*
                 * Send the create request to the MDT where the object
                 * will be located
                 */
                tgt = lmv_find_target(lmv, &op_data->op_fid2);
                if (IS_ERR(tgt))
                        return PTR_ERR(tgt);

                op_data->op_mds = tgt->ltd_idx;
        } else {
                CDEBUG(D_CONFIG, "Server doesn't support striped dirs\n");
        }

        CDEBUG(D_INODE, "CREATE obj "DFID" -> mds #%x\n",
               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_enqueue(struct obd_export *exp, struct ldlm_enqueue_info *einfo,
            const union ldlm_policy_data *policy,
            struct lookup_intent *it, struct md_op_data *op_data,
            struct lustre_handle *lockh, __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 #%u\n",
               LL_IT2STR(it), PFID(&op_data->op_fid1), tgt->ltd_idx);

        return md_enqueue(tgt->ltd_exp, einfo, policy, it, op_data, lockh,
                        extra_lock_flags);
}

static int
lmv_getattr_name(struct obd_export *exp, struct md_op_data *op_data,
                 struct ptlrpc_request **preq)
{
        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 #%u\n",
               (int)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, preq);
        if (rc != 0)
                return rc;

        body = req_capsule_server_get(&(*preq)->rq_pill, &RMF_MDT_BODY);
        if (body->mbo_valid & OBD_MD_MDS) {
                struct lu_fid rid = body->mbo_fid1;

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

                tgt = lmv_find_target(lmv, &rid);
                if (IS_ERR(tgt)) {
                        ptlrpc_req_finished(*preq);
                        *preq = NULL;
                        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(*preq);
                *preq = 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 lmv_tgt_desc *tgt,
                            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;
        union ldlm_policy_data policy = { { 0 } };
        int                  rc = 0;

        if (!fid_is_sane(fid))
                return 0;

        if (!tgt) {
                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), (int)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();
        if (op_data->op_mea2) {
                struct lmv_stripe_md *lsm = op_data->op_mea2;
                const struct lmv_oinfo *oinfo;

                oinfo = lsm_name_to_stripe_info(lsm, op_data->op_name,
                                                op_data->op_namelen);
                if (IS_ERR(oinfo))
                        return PTR_ERR(oinfo);

                op_data->op_fid2 = oinfo->lmo_fid;
        }

        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, NULL, op_data, tgt->ltd_idx, LCK_EX,
                              MDS_INODELOCK_UPDATE, MF_MDC_CANCEL_FID1);
        if (rc != 0)
                return rc;

        return md_link(tgt->ltd_exp, op_data, request);
}

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

        LASSERT(oldlen != 0);

        CDEBUG(D_INODE, "RENAME %.*s in "DFID":%d to %.*s in "DFID":%d\n",
               (int)oldlen, old, PFID(&op_data->op_fid1),
               op_data->op_mea1 ? op_data->op_mea1->lsm_md_stripe_count : 0,
               (int)newlen, new, PFID(&op_data->op_fid2),
               op_data->op_mea2 ? op_data->op_mea2->lsm_md_stripe_count : 0);

        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();

        if (op_data->op_cli_flags & CLI_MIGRATE) {
                LASSERTF(fid_is_sane(&op_data->op_fid3), "invalid FID "DFID"\n",
                         PFID(&op_data->op_fid3));

                if (op_data->op_mea1) {
                        struct lmv_stripe_md *lsm = op_data->op_mea1;
                        struct lmv_tgt_desc *tmp;

                        /* Fix the parent fid for striped dir */
                        tmp = lmv_locate_target_for_name(lmv, lsm, old,
                                                         oldlen,
                                                         &op_data->op_fid1,
                                                         NULL);
                        if (IS_ERR(tmp))
                                return PTR_ERR(tmp);
                }

                rc = lmv_fid_alloc(NULL, exp, &op_data->op_fid2, op_data);
                if (rc)
                        return rc;
                src_tgt = lmv_find_target(lmv, &op_data->op_fid3);
                if (IS_ERR(src_tgt))
                        return PTR_ERR(src_tgt);

                target_exp = src_tgt->ltd_exp;
        } else {
                if (op_data->op_mea1) {
                        struct lmv_stripe_md *lsm = op_data->op_mea1;

                        src_tgt = lmv_locate_target_for_name(lmv, lsm, old,
                                                             oldlen,
                                                             &op_data->op_fid1,
                                                             &op_data->op_mds);
                } else {
                        src_tgt = lmv_find_target(lmv, &op_data->op_fid1);
                }
                if (IS_ERR(src_tgt))
                        return PTR_ERR(src_tgt);

                if (op_data->op_mea2) {
                        struct lmv_stripe_md *lsm = op_data->op_mea2;

                        tgt_tgt = lmv_locate_target_for_name(lmv, lsm, new,
                                                             newlen,
                                                             &op_data->op_fid2,
                                                             &op_data->op_mds);
                } else {
                        tgt_tgt = lmv_find_target(lmv, &op_data->op_fid2);
                }
                if (IS_ERR(tgt_tgt))
                        return PTR_ERR(tgt_tgt);

                target_exp = tgt_tgt->ltd_exp;
        }

        /*
         * 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, NULL, op_data, src_tgt->ltd_idx,
                              LCK_EX, MDS_INODELOCK_UPDATE,
                              MF_MDC_CANCEL_FID2);
        if (rc)
                return rc;
        /*
         * Cancel LOOKUP locks on source child (fid3) for parent tgt_tgt.
         */
        if (fid_is_sane(&op_data->op_fid3)) {
                struct lmv_tgt_desc *tgt;

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

                /* Cancel LOOKUP lock on its parent */
                rc = lmv_early_cancel(exp, tgt, op_data, src_tgt->ltd_idx,
                                      LCK_EX, MDS_INODELOCK_LOOKUP,
                                      MF_MDC_CANCEL_FID3);
                if (rc)
                        return rc;

                rc = lmv_early_cancel(exp, NULL, op_data, src_tgt->ltd_idx,
                                      LCK_EX, MDS_INODELOCK_FULL,
                                      MF_MDC_CANCEL_FID3);
                if (rc)
                        return rc;
        }

retry_rename:
        /*
         * Cancel all the locks on tgt child (fid4).
         */
        if (fid_is_sane(&op_data->op_fid4)) {
                struct lmv_tgt_desc *tgt;

                rc = lmv_early_cancel(exp, NULL, op_data, src_tgt->ltd_idx,
                                      LCK_EX, MDS_INODELOCK_FULL,
                                      MF_MDC_CANCEL_FID4);
                if (rc)
                        return rc;

                tgt = lmv_find_target(lmv, &op_data->op_fid4);
                if (IS_ERR(tgt))
                        return PTR_ERR(tgt);

                /*
                 * Since the target child might be destroyed, and it might
                 * become orphan, and we can only check orphan on the local
                 * MDT right now, so we send rename request to the MDT where
                 * target child is located. If target child does not exist,
                 * then it will send the request to the target parent
                 */
                target_exp = tgt->ltd_exp;
        }

        rc = md_rename(target_exp, op_data, old, oldlen, new, newlen, request);
        if (rc && 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->mbo_valid & OBD_MD_MDS)))
                return rc;

        CDEBUG(D_INODE, "%s: try rename to another MDT for " DFID "\n",
               exp->exp_obd->obd_name, PFID(&body->mbo_fid1));

        op_data->op_fid4 = body->mbo_fid1;
        ptlrpc_req_finished(*request);
        *request = NULL;
        goto retry_rename;
}

static int lmv_setattr(struct obd_export *exp, struct md_op_data *op_data,
                       void *ea, size_t ealen, 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;

        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);

        return md_setattr(tgt->ltd_exp, op_data, ea, ealen, request);
}

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);

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

/**
 * Get current minimum entry from striped directory
 *
 * This function will search the dir entry, whose hash value is the
 * closest(>=) to @hash_offset, from all of sub-stripes, and it is
 * only being called for striped directory.
 *
 * \param[in] exp               export of LMV
 * \param[in] op_data           parameters transferred beween client MD stack
 *                              stripe_information will be included in this
 *                              parameter
 * \param[in] cb_op             ldlm callback being used in enqueue in
 *                              mdc_read_page
 * \param[in] hash_offset       the hash value, which is used to locate
 *                              minum(closet) dir entry
 * \param[in|out] stripe_offset the caller use this to indicate the stripe
 *                              index of last entry, so to avoid hash conflict
 *                              between stripes. It will also be used to
 *                              return the stripe index of current dir entry.
 * \param[in|out] entp          the minum entry and it also is being used
 *                              to input the last dir entry to resolve the
 *                              hash conflict
 *
 * \param[out] ppage            the page which holds the minum entry
 *
 * \retval                      = 0 get the entry successfully
 *                              negative errno (< 0) does not get the entry
 */
static int lmv_get_min_striped_entry(struct obd_export *exp,
                                     struct md_op_data *op_data,
                                     struct md_callback *cb_op,
                                     __u64 hash_offset, int *stripe_offset,
                                     struct lu_dirent **entp,
                                     struct page **ppage)
{
        struct lmv_stripe_md *lsm = op_data->op_mea1;
        struct obd_device *obd = exp->exp_obd;
        struct lmv_obd *lmv = &obd->u.lmv;
        struct lu_dirent *min_ent = NULL;
        struct page *min_page = NULL;
        struct lmv_tgt_desc *tgt;
        int stripe_count;
        int min_idx = 0;
        int rc = 0;
        int i;

        stripe_count = lsm->lsm_md_stripe_count;
        for (i = 0; i < stripe_count; i++) {
                __u64 stripe_hash = hash_offset;
                struct lu_dirent *ent = NULL;
                struct page *page = NULL;
                struct lu_dirpage *dp;

                tgt = lmv_get_target(lmv, lsm->lsm_md_oinfo[i].lmo_mds, NULL);
                if (IS_ERR(tgt)) {
                        rc = PTR_ERR(tgt);
                        goto out;
                }

                /*
                 * op_data will be shared by each stripe, so we need
                 * reset these value for each stripe
                 */
                op_data->op_fid1 = lsm->lsm_md_oinfo[i].lmo_fid;
                op_data->op_fid2 = lsm->lsm_md_oinfo[i].lmo_fid;
                op_data->op_data = lsm->lsm_md_oinfo[i].lmo_root;
next:
                rc = md_read_page(tgt->ltd_exp, op_data, cb_op, stripe_hash,
                                  &page);
                if (rc)
                        goto out;

                dp = page_address(page);
                for (ent = lu_dirent_start(dp); ent;
                     ent = lu_dirent_next(ent)) {
                        /* Skip dummy entry */
                        if (!le16_to_cpu(ent->lde_namelen))
                                continue;

                        if (le64_to_cpu(ent->lde_hash) < hash_offset)
                                continue;

                        if (le64_to_cpu(ent->lde_hash) == hash_offset &&
                            (*entp == ent || i < *stripe_offset))
                                continue;

                        /* skip . and .. for other stripes */
                        if (i && (!strncmp(ent->lde_name, ".",
                                           le16_to_cpu(ent->lde_namelen)) ||
                                  !strncmp(ent->lde_name, "..",
                                           le16_to_cpu(ent->lde_namelen))))
                                continue;
                        break;
                }

                if (!ent) {
                        stripe_hash = le64_to_cpu(dp->ldp_hash_end);

                        kunmap(page);
                        put_page(page);
                        page = NULL;

                        /*
                         * reach the end of current stripe, go to next stripe
                         */
                        if (stripe_hash == MDS_DIR_END_OFF)
                                continue;
                        else
                                goto next;
                }

                if (min_ent) {
                        if (le64_to_cpu(min_ent->lde_hash) >
                            le64_to_cpu(ent->lde_hash)) {
                                min_ent = ent;
                                kunmap(min_page);
                                put_page(min_page);
                                min_idx = i;
                                min_page = page;
                        } else {
                                kunmap(page);
                                put_page(page);
                                page = NULL;
                        }
                } else {
                        min_ent = ent;
                        min_page = page;
                        min_idx = i;
                }
        }

out:
        if (*ppage) {
                kunmap(*ppage);
                put_page(*ppage);
        }
        *stripe_offset = min_idx;
        *entp = min_ent;
        *ppage = min_page;
        return rc;
}

/**
 * Build dir entry page from a striped directory
 *
 * This function gets one entry by @offset from a striped directory. It will
 * read entries from all of stripes, and choose one closest to the required
 * offset(&offset). A few notes
 * 1. skip . and .. for non-zero stripes, because there can only have one .
 * and .. in a directory.
 * 2. op_data will be shared by all of stripes, instead of allocating new
 * one, so need to restore before reusing.
 * 3. release the entry page if that is not being chosen.
 *
 * \param[in] exp       obd export refer to LMV
 * \param[in] op_data   hold those MD parameters of read_entry
 * \param[in] cb_op     ldlm callback being used in enqueue in mdc_read_entry
 * \param[out] ldp      the entry being read
 * \param[out] ppage    the page holding the entry. Note: because the entry
 *                      will be accessed in upper layer, so we need hold the
 *                      page until the usages of entry is finished, see
 *                      ll_dir_entry_next.
 *
 * retval               =0 if get entry successfully
 *                      <0 cannot get entry
 */
static int lmv_read_striped_page(struct obd_export *exp,
                                 struct md_op_data *op_data,
                                 struct md_callback *cb_op,
                                 __u64 offset, struct page **ppage)
{
        struct inode *master_inode = op_data->op_data;
        struct lu_fid master_fid = op_data->op_fid1;
        struct obd_device *obd = exp->exp_obd;
        __u64 hash_offset = offset;
        struct page *min_ent_page = NULL;
        struct page *ent_page = NULL;
        struct lu_dirent *min_ent = NULL;
        struct lu_dirent *last_ent;
        struct lu_dirent *ent;
        struct lu_dirpage *dp;
        size_t left_bytes;
        int ent_idx = 0;
        void *area;
        int rc;

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

        /*
         * Allocate a page and read entries from all of stripes and fill
         * the page by hash order
         */
        ent_page = alloc_page(GFP_KERNEL);
        if (!ent_page)
                return -ENOMEM;

        /* Initialize the entry page */
        dp = kmap(ent_page);
        memset(dp, 0, sizeof(*dp));
        dp->ldp_hash_start = cpu_to_le64(offset);
        dp->ldp_flags |= LDF_COLLIDE;

        area = dp + 1;
        left_bytes = PAGE_SIZE - sizeof(*dp);
        ent = area;
        last_ent = ent;
        do {
                __u16 ent_size;

                /* Find the minum entry from all sub-stripes */
                rc = lmv_get_min_striped_entry(exp, op_data, cb_op, hash_offset,
                                               &ent_idx, &min_ent,
                                               &min_ent_page);
                if (rc)
                        goto out;

                /*
                 * If it can not get minum entry, it means it already reaches
                 * the end of this directory
                 */
                if (!min_ent) {
                        last_ent->lde_reclen = 0;
                        hash_offset = MDS_DIR_END_OFF;
                        goto out;
                }

                ent_size = le16_to_cpu(min_ent->lde_reclen);

                /*
                 * the last entry lde_reclen is 0, but it might not
                 * the end of this entry of this temporay entry
                 */
                if (!ent_size)
                        ent_size = lu_dirent_calc_size(
                                        le16_to_cpu(min_ent->lde_namelen),
                                        le32_to_cpu(min_ent->lde_attrs));
                if (ent_size > left_bytes) {
                        last_ent->lde_reclen = cpu_to_le16(0);
                        hash_offset = le64_to_cpu(min_ent->lde_hash);
                        goto out;
                }

                memcpy(ent, min_ent, ent_size);

                /*
                 * Replace . with master FID and Replace .. with the parent FID
                 * of master object
                 */
                if (!strncmp(ent->lde_name, ".",
                             le16_to_cpu(ent->lde_namelen)) &&
                    le16_to_cpu(ent->lde_namelen) == 1)
                        fid_cpu_to_le(&ent->lde_fid, &master_fid);
                else if (!strncmp(ent->lde_name, "..",
                                  le16_to_cpu(ent->lde_namelen)) &&
                         le16_to_cpu(ent->lde_namelen) == 2)
                        fid_cpu_to_le(&ent->lde_fid, &op_data->op_fid3);

                left_bytes -= ent_size;
                ent->lde_reclen = cpu_to_le16(ent_size);
                last_ent = ent;
                ent = (void *)ent + ent_size;
                hash_offset = le64_to_cpu(min_ent->lde_hash);
                if (hash_offset == MDS_DIR_END_OFF) {
                        last_ent->lde_reclen = 0;
                        break;
                }
        } while (1);
out:
        if (min_ent_page) {
                kunmap(min_ent_page);
                put_page(min_ent_page);
        }

        if (unlikely(rc)) {
                __free_page(ent_page);
                ent_page = NULL;
        } else {
                if (ent == area)
                        dp->ldp_flags |= LDF_EMPTY;
                dp->ldp_flags = cpu_to_le32(dp->ldp_flags);
                dp->ldp_hash_end = cpu_to_le64(hash_offset);
        }

        /*
         * We do not want to allocate md_op_data during each
         * dir entry reading, so op_data will be shared by every stripe,
         * then we need to restore it back to original value before
         * return to the upper layer
         */
        op_data->op_fid1 = master_fid;
        op_data->op_fid2 = master_fid;
        op_data->op_data = master_inode;

        *ppage = ent_page;

        return rc;
}

static int lmv_read_page(struct obd_export *exp, struct md_op_data *op_data,
                         struct md_callback *cb_op, __u64 offset,
                         struct page **ppage)
{
        struct lmv_stripe_md *lsm = op_data->op_mea1;
        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 (unlikely(lsm))
                return lmv_read_striped_page(exp, op_data, cb_op, offset, ppage);

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

        return md_read_page(tgt->ltd_exp, op_data, cb_op, offset, ppage);
}

/**
 * Unlink a file/directory
 *
 * Unlink a file or directory under the parent dir. The unlink request
 * usually will be sent to the MDT where the child is located, but if
 * the client does not have the child FID then request will be sent to the
 * MDT where the parent is located.
 *
 * If the parent is a striped directory then it also needs to locate which
 * stripe the name of the child is located, and replace the parent FID
 * (@op->op_fid1) with the stripe FID. Note: if the stripe is unknown,
 * it will walk through all of sub-stripes until the child is being
 * unlinked finally.
 *
 * \param[in] exp       export refer to LMV
 * \param[in] op_data   different parameters transferred beween client
 *                      MD stacks, name, namelen, FIDs etc.
 *                      op_fid1 is the parent FID, op_fid2 is the child
 *                      FID.
 * \param[out] request point to the request of unlink.
 *
 * retval               0 if succeed
 *                      negative errno if failed.
 */
static int lmv_unlink(struct obd_export *exp, struct md_op_data *op_data,
                      struct ptlrpc_request **request)
{
        struct lmv_stripe_md *lsm = op_data->op_mea1;
        struct obd_device    *obd = exp->exp_obd;
        struct lmv_obd    *lmv = &obd->u.lmv;
        struct lmv_tgt_desc *parent_tgt = NULL;
        struct lmv_tgt_desc     *tgt = NULL;
        struct mdt_body         *body;
        int stripe_index = 0;
        int                  rc;

        rc = lmv_check_connect(obd);
        if (rc)
                return rc;
retry_unlink:
        /* For striped dir, we need to locate the parent as well */
        if (lsm) {
                struct lmv_tgt_desc *tmp;

                LASSERT(op_data->op_name && op_data->op_namelen);

                tmp = lmv_locate_target_for_name(lmv, lsm,
                                                 op_data->op_name,
                                                 op_data->op_namelen,
                                                 &op_data->op_fid1,
                                                 &op_data->op_mds);

                /*
                 * return -EBADFD means unknown hash type, might
                 * need try all sub-stripe here
                 */
                if (IS_ERR(tmp) && PTR_ERR(tmp) != -EBADFD)
                        return PTR_ERR(tmp);

                /*
                 * Note: both migrating dir and unknown hash dir need to
                 * try all of sub-stripes, so we need start search the
                 * name from stripe 0, but migrating dir is already handled
                 * inside lmv_locate_target_for_name(), so we only check
                 * unknown hash type directory here
                 */
                if (!lmv_is_known_hash_type(lsm->lsm_md_hash_type)) {
                        struct lmv_oinfo *oinfo;

                        oinfo = &lsm->lsm_md_oinfo[stripe_index];

                        op_data->op_fid1 = oinfo->lmo_fid;
                        op_data->op_mds = oinfo->lmo_mds;
                }
        }

try_next_stripe:
        /* Send unlink requests to the MDT where the child is located */
        if (likely(!fid_is_zero(&op_data->op_fid2)))
                tgt = lmv_find_target(lmv, &op_data->op_fid2);
        else if (lsm)
                tgt = lmv_get_target(lmv, op_data->op_mds, NULL);
        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).
         */
        parent_tgt = lmv_find_target(lmv, &op_data->op_fid1);
        if (IS_ERR(parent_tgt))
                return PTR_ERR(parent_tgt);

        if (parent_tgt != tgt) {
                rc = lmv_early_cancel(exp, parent_tgt, op_data, tgt->ltd_idx,
                                      LCK_EX, MDS_INODELOCK_LOOKUP,
                                      MF_MDC_CANCEL_FID3);
        }

        rc = lmv_early_cancel(exp, NULL, 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 #%u\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  && rc != -ENOENT)
                return rc;

        /* Try next stripe if it is needed. */
        if (rc == -ENOENT && lsm && lmv_need_try_all_stripes(lsm)) {
                struct lmv_oinfo *oinfo;

                stripe_index++;
                if (stripe_index >= lsm->lsm_md_stripe_count)
                        return rc;

                oinfo = &lsm->lsm_md_oinfo[stripe_index];

                op_data->op_fid1 = oinfo->lmo_fid;
                op_data->op_mds = oinfo->lmo_mds;

                ptlrpc_req_finished(*request);
                *request = NULL;

                goto try_next_stripe;
        }

        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->mbo_valid & OBD_MD_MDS)))
                return rc;

        CDEBUG(D_INODE, "%s: try unlink to another MDT for "DFID"\n",
               exp->exp_obd->obd_name, PFID(&body->mbo_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->mbo_fid1;
        ptlrpc_req_finished(*request);
        *request = NULL;

        goto retry_unlink;
}

static int lmv_precleanup(struct obd_device *obd)
{
        fld_client_debugfs_fini(&obd->u.lmv.lmv_fld);
        lprocfs_obd_cleanup(obd);
        return 0;
}

/**
 * Get by key a value associated with a LMV device.
 *
 * Dispatch request to lower-layer devices as needed.
 *
 * \param[in]  env      execution environment for this thread
 * \param[in]  exp      export for the LMV device
 * \param[in]  keylen   length of key identifier
 * \param[in]  key      identifier of key to get value for
 * \param[in]  vallen   size of \a val
 * \param[out] val      pointer to storage location for value
 *
 * \retval 0            on success
 * \retval negative     negated errno on failure
 */
static int lmv_get_info(const struct lu_env *env, struct obd_export *exp,
                        __u32 keylen, void *key, __u32 *vallen, void *val)
{
        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")) {
                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++) {
                        struct lmv_tgt_desc *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))
                                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);
                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;
}

/**
 * Asynchronously set by key a value associated with a LMV device.
 *
 * Dispatch request to lower-layer devices as needed.
 *
 * \param[in] env       execution environment for this thread
 * \param[in] exp       export for the LMV device
 * \param[in] keylen    length of key identifier
 * \param[in] key       identifier of key to store value for
 * \param[in] vallen    size of value to store
 * \param[in] val       pointer to data to be stored
 * \param[in] set       optional list of related ptlrpc requests
 *
 * \retval 0            on success
 * \retval negative     negated errno on failure
 */
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) ||
            KEY_IS(KEY_DEFAULT_EASIZE)) {
                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_unpack_md_v1(struct obd_export *exp, struct lmv_stripe_md *lsm,
                            const struct lmv_mds_md_v1 *lmm1)
{
        struct lmv_obd *lmv = &exp->exp_obd->u.lmv;
        int stripe_count;
        int rc = 0;
        int cplen;
        int i;

        lsm->lsm_md_magic = le32_to_cpu(lmm1->lmv_magic);
        lsm->lsm_md_stripe_count = le32_to_cpu(lmm1->lmv_stripe_count);
        lsm->lsm_md_master_mdt_index = le32_to_cpu(lmm1->lmv_master_mdt_index);
        if (OBD_FAIL_CHECK(OBD_FAIL_UNKNOWN_LMV_STRIPE))
                lsm->lsm_md_hash_type = LMV_HASH_TYPE_UNKNOWN;
        else
                lsm->lsm_md_hash_type = le32_to_cpu(lmm1->lmv_hash_type);
        lsm->lsm_md_layout_version = le32_to_cpu(lmm1->lmv_layout_version);
        cplen = strlcpy(lsm->lsm_md_pool_name, lmm1->lmv_pool_name,
                        sizeof(lsm->lsm_md_pool_name));

        if (cplen >= sizeof(lsm->lsm_md_pool_name))
                return -E2BIG;

        CDEBUG(D_INFO, "unpack lsm count %d, master %d hash_type %d layout_version %d\n",
               lsm->lsm_md_stripe_count, lsm->lsm_md_master_mdt_index,
               lsm->lsm_md_hash_type, lsm->lsm_md_layout_version);

        stripe_count = le32_to_cpu(lmm1->lmv_stripe_count);
        for (i = 0; i < stripe_count; i++) {
                fid_le_to_cpu(&lsm->lsm_md_oinfo[i].lmo_fid,
                              &lmm1->lmv_stripe_fids[i]);
                rc = lmv_fld_lookup(lmv, &lsm->lsm_md_oinfo[i].lmo_fid,
                                    &lsm->lsm_md_oinfo[i].lmo_mds);
                if (rc)
                        return rc;
                CDEBUG(D_INFO, "unpack fid #%d "DFID"\n", i,
                       PFID(&lsm->lsm_md_oinfo[i].lmo_fid));
        }

        return rc;
}

static int lmv_unpackmd(struct obd_export *exp, struct lmv_stripe_md **lsmp,
                        const union lmv_mds_md *lmm, size_t lmm_size)
{
        struct lmv_stripe_md *lsm;
        bool allocated = false;
        int lsm_size, rc;

        LASSERT(lsmp);

        lsm = *lsmp;
        /* Free memmd */
        if (lsm && !lmm) {
                int i;

                for (i = 1; i < lsm->lsm_md_stripe_count; i++) {
                        /*
                         * For migrating inode, the master stripe and master
                         * object will be the same, so do not need iput, see
                         * ll_update_lsm_md
                         */
                        if (!(lsm->lsm_md_hash_type & LMV_HASH_FLAG_MIGRATION &&
                              !i) && lsm->lsm_md_oinfo[i].lmo_root)
                                iput(lsm->lsm_md_oinfo[i].lmo_root);
                }

                kvfree(lsm);
                *lsmp = NULL;
                return 0;
        }

        if (le32_to_cpu(lmm->lmv_magic) == LMV_MAGIC_STRIPE)
                return -EPERM;

        /* Unpack memmd */
        if (le32_to_cpu(lmm->lmv_magic) != LMV_MAGIC_V1 &&
            le32_to_cpu(lmm->lmv_magic) != LMV_USER_MAGIC) {
                CERROR("%s: invalid lmv magic %x: rc = %d\n",
                       exp->exp_obd->obd_name, le32_to_cpu(lmm->lmv_magic),
                       -EIO);
                return -EIO;
        }

        if (le32_to_cpu(lmm->lmv_magic) == LMV_MAGIC_V1)
                lsm_size = lmv_stripe_md_size(lmv_mds_md_stripe_count_get(lmm));
        else
                /**
                 * Unpack default dirstripe(lmv_user_md) to lmv_stripe_md,
                 * stripecount should be 0 then.
                 */
                lsm_size = lmv_stripe_md_size(0);

        if (!lsm) {
                lsm = libcfs_kvzalloc(lsm_size, GFP_NOFS);
                if (!lsm)
                        return -ENOMEM;
                allocated = true;
                *lsmp = lsm;
        }

        switch (le32_to_cpu(lmm->lmv_magic)) {
        case LMV_MAGIC_V1:
                rc = lmv_unpack_md_v1(exp, lsm, &lmm->lmv_md_v1);
                break;
        default:
                CERROR("%s: unrecognized magic %x\n", exp->exp_obd->obd_name,
                       le32_to_cpu(lmm->lmv_magic));
                rc = -EINVAL;
                break;
        }

        if (rc && allocated) {
                kvfree(lsm);
                *lsmp = NULL;
                lsm_size = rc;
        }
        return lsm_size;
}

void lmv_free_memmd(struct lmv_stripe_md *lsm)
{
        lmv_unpackmd(NULL, &lsm, NULL, 0);
}
EXPORT_SYMBOL(lmv_free_memmd);

static int lmv_cancel_unused(struct obd_export *exp, const struct lu_fid *fid,
                             union ldlm_policy_data *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;
        u32 i;

        LASSERT(fid);

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

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

                err = md_cancel_unused(tgt->ltd_exp, fid, policy, mode, flags,
                                       opaque);
                if (!rc)
                        rc = err;
        }
        return rc;
}

static int lmv_set_lock_data(struct obd_export *exp,
                             const struct lustre_handle *lockh,
                             void *data, __u64 *bits)
{
        struct lmv_obd    *lmv = &exp->exp_obd->u.lmv;
        struct lmv_tgt_desc *tgt = lmv->tgts[0];

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

        return md_set_lock_data(tgt->ltd_exp, lockh, data, bits);
}

static enum ldlm_mode lmv_lock_match(struct obd_export *exp, __u64 flags,
                                     const struct lu_fid *fid,
                                     enum ldlm_type type,
                                     union ldlm_policy_data *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 tgt;
        u32 i;

        CDEBUG(D_INODE, "Lock match 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.  Try the MDT that the FID maps to first,
         * since this can be easily found, and only try others if that fails.
         */
        for (i = 0, tgt = lmv_find_target_index(lmv, fid);
             i < lmv->desc.ld_tgt_count;
             i++, tgt = (tgt + 1) % lmv->desc.ld_tgt_count) {
                if (tgt < 0) {
                        CDEBUG(D_HA, "%s: "DFID" is inaccessible: rc = %d\n",
                               obd->obd_name, PFID(fid), tgt);
                        tgt = 0;
                }

                if (!lmv->tgts[tgt] || !lmv->tgts[tgt]->ltd_exp ||
                    !lmv->tgts[tgt]->ltd_active)
                        continue;

                rc = md_lock_match(lmv->tgts[tgt]->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;
        struct lmv_tgt_desc *tgt = lmv->tgts[0];

        if (!tgt || !tgt->ltd_exp)
                return -EINVAL;
        return md_get_lustre_md(tgt->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;
        struct lmv_tgt_desc *tgt = lmv->tgts[0];

        if (md->lmv) {
                lmv_free_memmd(md->lmv);
                md->lmv = NULL;
        }
        if (!tgt || !tgt->ltd_exp)
                return -EINVAL;
        return md_free_lustre_md(tgt->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_intent_getattr_async(struct obd_export *exp,
                                    struct md_enqueue_info *minfo)
{
        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 *ptgt = NULL;
        struct lmv_tgt_desc *ctgt = NULL;
        int                   rc;

        if (!fid_is_sane(&op_data->op_fid2))
                return -EINVAL;

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

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

        ctgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid2);
        if (IS_ERR(ctgt))
                return PTR_ERR(ctgt);

        /*
         * if child is on remote MDT, we need 2 async RPCs to fetch both LOOKUP
         * lock on parent, and UPDATE lock on child MDT, which makes all
         * complicated. Considering remote dir is rare case, and not supporting
         * it in statahead won't cause any issue, drop its support for now.
         */
        if (ptgt != ctgt)
                return -ENOTSUPP;

        return md_intent_getattr_async(ptgt->ltd_exp, minfo);
}

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);

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

static int
lmv_get_fid_from_lsm(struct obd_export *exp,
                     const struct lmv_stripe_md *lsm,
                     const char *name, int namelen, struct lu_fid *fid)
{
        const struct lmv_oinfo *oinfo;

        LASSERT(lsm);
        oinfo = lsm_name_to_stripe_info(lsm, name, namelen);
        if (IS_ERR(oinfo))
                return PTR_ERR(oinfo);

        *fid = oinfo->lmo_fid;

        return 0;
}

/**
 * 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;
        __u64 curspace = 0, curinodes = 0;
        u32 i;

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

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

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

                tgt = lmv->tgts[i];

                if (!tgt || !tgt->ltd_exp || !tgt->ltd_active)
                        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_merge_attr(struct obd_export *exp,
                          const struct lmv_stripe_md *lsm,
                          struct cl_attr *attr,
                          ldlm_blocking_callback cb_blocking)
{
        int rc, i;

        rc = lmv_revalidate_slaves(exp, lsm, cb_blocking, 0);
        if (rc < 0)
                return rc;

        for (i = 0; i < lsm->lsm_md_stripe_count; i++) {
                struct inode *inode = lsm->lsm_md_oinfo[i].lmo_root;

                CDEBUG(D_INFO, ""DFID" size %llu, blocks %llu nlink %u, atime %lu ctime %lu, mtime %lu.\n",
                       PFID(&lsm->lsm_md_oinfo[i].lmo_fid),
                       i_size_read(inode), (unsigned long long)inode->i_blocks,
                       inode->i_nlink, LTIME_S(inode->i_atime),
                       LTIME_S(inode->i_ctime), LTIME_S(inode->i_mtime));

                /* for slave stripe, it needs to subtract nlink for . and .. */
                if (i)
                        attr->cat_nlink += inode->i_nlink - 2;
                else
                        attr->cat_nlink = inode->i_nlink;

                attr->cat_size += i_size_read(inode);
                attr->cat_blocks += inode->i_blocks;

                if (attr->cat_atime < LTIME_S(inode->i_atime))
                        attr->cat_atime = LTIME_S(inode->i_atime);

                if (attr->cat_ctime < LTIME_S(inode->i_ctime))
                        attr->cat_ctime = LTIME_S(inode->i_ctime);

                if (attr->cat_mtime < LTIME_S(inode->i_mtime))
                        attr->cat_mtime = LTIME_S(inode->i_mtime);
        }
        return 0;
}

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,
        .notify         = lmv_notify,
        .get_uuid       = lmv_get_uuid,
        .iocontrol      = lmv_iocontrol,
        .quotactl       = lmv_quotactl
};

static struct md_ops lmv_md_ops = {
        .getstatus              = lmv_getstatus,
        .null_inode             = lmv_null_inode,
        .close                  = lmv_close,
        .create                 = lmv_create,
        .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,
        .read_page              = lmv_read_page,
        .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,
        .merge_attr             = lmv_merge_attr,
        .set_open_replay_data   = lmv_set_open_replay_data,
        .clear_open_replay_data = lmv_clear_open_replay_data,
        .intent_getattr_async   = lmv_intent_getattr_async,
        .revalidate_lock        = lmv_revalidate_lock,
        .get_fid_from_lsm       = lmv_get_fid_from_lsm,
        .unpackmd               = lmv_unpackmd,
};

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

        lprocfs_lmv_init_vars(&lvars);

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

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);