[fs/lustre-release.git] / lustre / lod / lod_lov.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 COPYING 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  2009 Sun Microsystems, Inc. All rights reserved
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2017, Intel Corporation.
 */
/*
 * lustre/lod/lod_lov.c
 *
 * A set of helpers to maintain Logical Object Volume (LOV)
 * Extended Attribute (EA) and known OST targets
 *
 * Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
 */

#define DEBUG_SUBSYSTEM S_MDS

#include <obd_class.h>
#include <lustre_lfsck.h>
#include <lustre_lmv.h>
#include <lustre_swab.h>

#include "lod_internal.h"

/**
 * Increase reference count on the target table.
 *
 * Increase reference count on the target table usage to prevent racing with
 * addition/deletion. Any function that expects the table to remain
 * stationary must take a ref.
 *
 * \param[in] ltd       target table (lod_ost_descs or lod_mdt_descs)
 */
void lod_getref(struct lod_tgt_descs *ltd)
{
        down_read(&ltd->ltd_rw_sem);
        mutex_lock(&ltd->ltd_mutex);
        ltd->ltd_refcount++;
        mutex_unlock(&ltd->ltd_mutex);
}

/**
 * Decrease reference count on the target table.
 *
 * Companion of lod_getref() to release a reference on the target table.
 * If this is the last reference and the OST entry was scheduled for deletion,
 * the descriptor is removed from the table.
 *
 * \param[in] lod       LOD device from which we release a reference
 * \param[in] ltd       target table (lod_ost_descs or lod_mdt_descs)
 */
void lod_putref(struct lod_device *lod, struct lod_tgt_descs *ltd)
{
        mutex_lock(&ltd->ltd_mutex);
        ltd->ltd_refcount--;
        if (ltd->ltd_refcount == 0 && ltd->ltd_death_row) {
                struct lod_tgt_desc *tgt_desc, *tmp;
                LIST_HEAD(kill);

                CDEBUG(D_CONFIG, "destroying %d ltd desc\n",
                       ltd->ltd_death_row);

                ltd_foreach_tgt_safe(ltd, tgt_desc, tmp) {
                        LASSERT(tgt_desc);
                        if (!tgt_desc->ltd_reap)
                                continue;

                        list_add(&tgt_desc->ltd_kill, &kill);
                        lu_tgt_pool_remove(&ltd->ltd_tgt_pool,
                                           tgt_desc->ltd_index);
                        ltd_del_tgt(ltd, tgt_desc);
                        ltd->ltd_death_row--;
                }
                mutex_unlock(&ltd->ltd_mutex);
                up_read(&ltd->ltd_rw_sem);

                list_for_each_entry_safe(tgt_desc, tmp, &kill, ltd_kill) {
                        int rc;

                        list_del(&tgt_desc->ltd_kill);
                        rc = obd_disconnect(tgt_desc->ltd_exp);
                        if (rc)
                                CERROR("%s: failed to disconnect %s: rc = %d\n",
                                       lod2obd(lod)->obd_name,
                                       obd_uuid2str(&tgt_desc->ltd_uuid), rc);
                        OBD_FREE_PTR(tgt_desc);
                }
        } else {
                mutex_unlock(&ltd->ltd_mutex);
                up_read(&ltd->ltd_rw_sem);
        }
}

/**
 * Connect LOD to a new OSP and add it to the target table.
 *
 * Connect to the OSP device passed, initialize all the internal
 * structures related to the device and add it to the target table.
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lod               LOD device to be connected to the new OSP
 * \param[in] osp               name of OSP device name to be added
 * \param[in] index             index of the new target
 * \param[in] gen               target's generation number
 * \param[in] tgt_index         OSP's group
 * \param[in] type              type of device (mdc or osc)
 * \param[in] active            state of OSP: 0 - inactive, 1 - active
 *
 * \retval                      0 if added successfully
 * \retval                      negative error number on failure
 */
int lod_add_device(const struct lu_env *env, struct lod_device *lod,
                   char *osp, unsigned index, unsigned gen, int tgt_index,
                   char *type, int active)
{
        struct obd_connect_data *data = NULL;
        struct obd_export       *exp = NULL;
        struct obd_device       *obd;
        struct lu_device        *lu_dev;
        struct dt_device        *dt_dev;
        int                      rc;
        struct lod_tgt_desc     *tgt_desc;
        struct lod_tgt_descs    *ltd;
        struct lustre_cfg       *lcfg;
        struct obd_uuid         obd_uuid;
        bool                    for_ost;
        bool connected = false;
        ENTRY;

        CDEBUG(D_CONFIG, "osp:%s idx:%d gen:%d\n", osp, index, gen);

        if (gen <= 0) {
                CERROR("request to add OBD %s with invalid generation: %d\n",
                       osp, gen);
                RETURN(-EINVAL);
        }

        obd_str2uuid(&obd_uuid, osp);

        obd = class_find_client_obd(&obd_uuid, LUSTRE_OSP_NAME,
                                &lod->lod_dt_dev.dd_lu_dev.ld_obd->obd_uuid);
        if (obd == NULL) {
                CERROR("can't find %s device\n", osp);
                RETURN(-EINVAL);
        }

        LASSERT(obd->obd_lu_dev != NULL);
        LASSERT(obd->obd_lu_dev->ld_site == lod->lod_dt_dev.dd_lu_dev.ld_site);

        lu_dev = obd->obd_lu_dev;
        dt_dev = lu2dt_dev(lu_dev);

        OBD_ALLOC_PTR(data);
        if (data == NULL)
                GOTO(out_cleanup, rc = -ENOMEM);

        data->ocd_connect_flags = OBD_CONNECT_INDEX | OBD_CONNECT_VERSION |
                                  OBD_CONNECT_FLAGS2;
        data->ocd_version = LUSTRE_VERSION_CODE;
        data->ocd_index = index;

        if (strcmp(LUSTRE_OSC_NAME, type) == 0) {
                for_ost = true;
                data->ocd_connect_flags |= OBD_CONNECT_AT |
                                           OBD_CONNECT_FULL20 |
                                           OBD_CONNECT_INDEX |
#ifdef HAVE_LRU_RESIZE_SUPPORT
                                           OBD_CONNECT_LRU_RESIZE |
#endif
                                           OBD_CONNECT_MDS |
                                           OBD_CONNECT_REQPORTAL |
                                           OBD_CONNECT_SKIP_ORPHAN |
                                           OBD_CONNECT_FID |
                                           OBD_CONNECT_LVB_TYPE |
                                           OBD_CONNECT_VERSION |
                                           OBD_CONNECT_PINGLESS |
                                           OBD_CONNECT_LFSCK |
                                           OBD_CONNECT_BULK_MBITS;
                data->ocd_connect_flags2 = OBD_CONNECT2_REPLAY_CREATE;

                data->ocd_group = tgt_index;
                ltd = &lod->lod_ost_descs;
        } else {
                struct obd_import *imp = obd->u.cli.cl_import;

                for_ost = false;
                data->ocd_ibits_known = MDS_INODELOCK_UPDATE;
                data->ocd_connect_flags |= OBD_CONNECT_ACL |
                                           OBD_CONNECT_IBITS |
                                           OBD_CONNECT_MDS_MDS |
                                           OBD_CONNECT_MULTIMODRPCS |
                                           OBD_CONNECT_FID |
                                           OBD_CONNECT_AT |
                                           OBD_CONNECT_FULL20 |
                                           OBD_CONNECT_LFSCK |
                                           OBD_CONNECT_BULK_MBITS;
                spin_lock(&imp->imp_lock);
                imp->imp_server_timeout = 1;
                spin_unlock(&imp->imp_lock);
                imp->imp_client->cli_request_portal = OUT_PORTAL;
                CDEBUG(D_OTHER, "%s: Set 'mds' portal and timeout\n",
                      obd->obd_name);
                ltd = &lod->lod_mdt_descs;
        }

        rc = obd_connect(env, &exp, obd, &obd->obd_uuid, data, NULL);
        OBD_FREE_PTR(data);
        if (rc) {
                CERROR("%s: cannot connect to next dev %s (%d)\n",
                       obd->obd_name, osp, rc);
                GOTO(out_cleanup, rc);
        }
        connected = true;

        /* Allocate ost descriptor and fill it */
        OBD_ALLOC_PTR(tgt_desc);
        if (!tgt_desc)
                GOTO(out_cleanup, rc = -ENOMEM);

        tgt_desc->ltd_tgt    = dt_dev;
        tgt_desc->ltd_exp    = exp;
        tgt_desc->ltd_uuid   = obd->u.cli.cl_target_uuid;
        tgt_desc->ltd_gen    = gen;
        tgt_desc->ltd_index  = index;
        tgt_desc->ltd_active = active;

        down_write(&ltd->ltd_rw_sem);
        mutex_lock(&ltd->ltd_mutex);
        rc = ltd_add_tgt(ltd, tgt_desc);
        if (rc)
                GOTO(out_mutex, rc);

        rc = lu_qos_add_tgt(&ltd->ltd_qos, tgt_desc);
        if (rc)
                GOTO(out_del_tgt, rc);

        rc = lu_tgt_pool_add(&ltd->ltd_tgt_pool, index,
                          ltd->ltd_lov_desc.ld_tgt_count);
        if (rc) {
                CERROR("%s: can't set up pool, failed with %d\n",
                       obd->obd_name, rc);
                GOTO(out_del_tgt, rc);
        }

        mutex_unlock(&ltd->ltd_mutex);
        up_write(&ltd->ltd_rw_sem);

        if (lod->lod_recovery_completed)
                lu_dev->ld_ops->ldo_recovery_complete(env, lu_dev);

        if (!for_ost && lod->lod_initialized) {
                rc = lod_sub_init_llog(env, lod, tgt_desc->ltd_tgt);
                if (rc != 0) {
                        CERROR("%s: cannot start llog on %s:rc = %d\n",
                               lod2obd(lod)->obd_name, osp, rc);
                        GOTO(out_ltd, rc);
                }
        }

        rc = lfsck_add_target(env, lod->lod_child, dt_dev, exp, index, for_ost);
        if (rc != 0) {
                CERROR("Fail to add LFSCK target: name = %s, type = %s, "
                       "index = %u, rc = %d\n", osp, type, index, rc);
                GOTO(out_fini_llog, rc);
        }
        RETURN(rc);
out_fini_llog:
        lod_sub_fini_llog(env, tgt_desc->ltd_tgt,
                          &tgt_desc->ltd_recovery_task);
out_ltd:
        down_write(&ltd->ltd_rw_sem);
        mutex_lock(&ltd->ltd_mutex);
        lu_tgt_pool_remove(&ltd->ltd_tgt_pool, index);
out_del_tgt:
        ltd_del_tgt(ltd, tgt_desc);
out_mutex:
        mutex_unlock(&ltd->ltd_mutex);
        up_write(&ltd->ltd_rw_sem);
        OBD_FREE_PTR(tgt_desc);
out_cleanup:
        /* XXX OSP needs us to send down LCFG_CLEANUP because it uses
         * objects from the MDT stack. See LU-7184. */
        lcfg = &lod_env_info(env)->lti_lustre_cfg;
        memset(lcfg, 0, sizeof(*lcfg));
        lcfg->lcfg_version = LUSTRE_CFG_VERSION;
        lcfg->lcfg_command = LCFG_CLEANUP;
        lu_dev->ld_ops->ldo_process_config(env, lu_dev, lcfg);

        if (connected)
                obd_disconnect(exp);

        return rc;
}

/**
 * Schedule target removal from the target table.
 *
 * Mark the device as dead. The device is not removed here because it may
 * still be in use. The device will be removed in lod_putref() when the
 * last reference is released.
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lod               LOD device the target table belongs to
 * \param[in] ltd               target table
 * \param[in] tgt               target
 */
static void __lod_del_device(const struct lu_env *env, struct lod_device *lod,
                             struct lod_tgt_descs *ltd, struct lu_tgt_desc *tgt)
{
        lfsck_del_target(env, lod->lod_child, tgt->ltd_tgt, tgt->ltd_index,
                         !ltd->ltd_is_mdt);

        if (!tgt->ltd_reap) {
                tgt->ltd_reap = 1;
                ltd->ltd_death_row++;
        }
}

/**
 * Schedule removal of all the targets from the given target table.
 *
 * See more details in the description for __lod_del_device()
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lod               LOD device the target table belongs to
 * \param[in] ltd               target table
 *
 * \retval                      0 always
 */
int lod_fini_tgt(const struct lu_env *env, struct lod_device *lod,
                 struct lod_tgt_descs *ltd)
{
        struct lu_tgt_desc *tgt;

        if (ltd->ltd_tgts_size <= 0)
                return 0;

        lod_getref(ltd);
        mutex_lock(&ltd->ltd_mutex);
        ltd_foreach_tgt(ltd, tgt)
                __lod_del_device(env, lod, ltd, tgt);
        mutex_unlock(&ltd->ltd_mutex);
        lod_putref(lod, ltd);

        lu_tgt_descs_fini(ltd);

        return 0;
}

/**
 * Remove device by name.
 *
 * Remove a device identified by \a osp from the target table. Given
 * the device can be in use, the real deletion happens in lod_putref().
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lod               LOD device to be connected to the new OSP
 * \param[in] ltd               target table
 * \param[in] osp               name of OSP device to be removed
 * \param[in] idx               index of the target
 * \param[in] gen               generation number, not used currently
 *
 * \retval                      0 if the device was scheduled for removal
 * \retval                      -EINVAL if no device was found
 */
int lod_del_device(const struct lu_env *env, struct lod_device *lod,
                   struct lod_tgt_descs *ltd, char *osp, unsigned int idx,
                   unsigned int gen)
{
        struct obd_device *obd;
        struct lu_tgt_desc *tgt;
        struct obd_uuid uuid;
        int rc = 0;

        ENTRY;

        CDEBUG(D_CONFIG, "osp:%s idx:%d gen:%d\n", osp, idx, gen);

        obd_str2uuid(&uuid, osp);

        obd = class_find_client_obd(&uuid, LUSTRE_OSP_NAME,
                                   &lod->lod_dt_dev.dd_lu_dev.ld_obd->obd_uuid);
        if (obd == NULL) {
                CERROR("can't find %s device\n", osp);
                RETURN(-EINVAL);
        }

        if (gen <= 0) {
                CERROR("%s: request to remove OBD %s with invalid generation %d"
                       "\n", obd->obd_name, osp, gen);
                RETURN(-EINVAL);
        }

        obd_str2uuid(&uuid,  osp);

        lod_getref(ltd);
        mutex_lock(&ltd->ltd_mutex);
        tgt = LTD_TGT(ltd, idx);
        /* check that the index is allocated in the bitmap */
        if (!test_bit(idx, ltd->ltd_tgt_bitmap) || !tgt) {
                CERROR("%s: device %d is not set up\n", obd->obd_name, idx);
                GOTO(out, rc = -EINVAL);
        }

        /* check that the UUID matches */
        if (!obd_uuid_equals(&uuid, &tgt->ltd_uuid)) {
                CERROR("%s: LOD target UUID %s at index %d does not match %s\n",
                       obd->obd_name, obd_uuid2str(&tgt->ltd_uuid), idx, osp);
                GOTO(out, rc = -EINVAL);
        }

        __lod_del_device(env, lod, ltd, tgt);
        EXIT;
out:
        mutex_unlock(&ltd->ltd_mutex);
        lod_putref(lod, ltd);
        return(rc);
}

/**
 * Resize per-thread storage to hold specified size.
 *
 * A helper function to resize per-thread temporary storage. This storage
 * is used to process LOV/LVM EAs and may be quite large. We do not want to
 * allocate/release it every time, so instead we put it into the env and
 * reallocate on demand. The memory is released when the correspondent thread
 * is finished.
 *
 * \param[in] info              LOD-specific storage in the environment
 * \param[in] size              new size to grow the buffer to

 * \retval                      0 on success, -ENOMEM if reallocation failed
 */
int lod_ea_store_resize(struct lod_thread_info *info, size_t size)
{
        __u32 round = size_roundup_power2(size);

        if (info->lti_ea_store) {
                LASSERT(info->lti_ea_store_size);
                CDEBUG(D_INFO, "EA store size %d is not enough, need %d\n",
                       info->lti_ea_store_size, round);
                OBD_FREE_LARGE(info->lti_ea_store, info->lti_ea_store_size);
                info->lti_ea_store = NULL;
                info->lti_ea_store_size = 0;
        }

        OBD_ALLOC_LARGE(info->lti_ea_store, round);
        if (info->lti_ea_store == NULL)
                RETURN(-ENOMEM);
        info->lti_ea_store_size = round;

        RETURN(0);
}

static void lod_free_comp_buffer(struct lod_layout_component *entries,
                                 __u16 count, __u32 bufsize)
{
        struct lod_layout_component *entry;
        int i;

        for (i = 0; i < count; i++) {
                entry = &entries[i];
                if (entry->llc_magic == LOV_MAGIC_FOREIGN)
                        continue;
                if (entry->llc_pool != NULL)
                        lod_set_pool(&entry->llc_pool, NULL);
                if (entry->llc_ostlist.op_array) {
                        OBD_FREE(entry->llc_ostlist.op_array,
                                 entry->llc_ostlist.op_size);
                        entry->llc_ostlist.op_array = NULL;
                        entry->llc_ostlist.op_size = 0;
                }
                LASSERT(entry->llc_stripe == NULL);
                LASSERT(entry->llc_stripes_allocated == 0);
        }

        if (bufsize != 0)
                OBD_FREE_LARGE(entries, bufsize);
}

void lod_free_def_comp_entries(struct lod_default_striping *lds)
{
        lod_free_comp_buffer(lds->lds_def_comp_entries,
                             lds->lds_def_comp_size_cnt,
                             size_roundup_power2(
                                     sizeof(*lds->lds_def_comp_entries) *
                                     lds->lds_def_comp_size_cnt));
        lds->lds_def_comp_entries = NULL;
        lds->lds_def_comp_cnt = 0;
        lds->lds_def_striping_is_composite = 0;
        lds->lds_def_comp_size_cnt = 0;
}

/**
 * Resize per-thread storage to hold default striping component entries
 *
 * A helper function to resize per-thread temporary storage. This storage
 * is used to hold default LOV/LVM EAs and may be quite large. We do not want
 * to allocate/release it every time, so instead we put it into the env and
 * reallocate it on demand. The memory is released when the correspondent
 * thread is finished.
 *
 * \param[in,out] lds           default striping
 * \param[in] count             new component count to grow the buffer to

 * \retval                      0 on success, -ENOMEM if reallocation failed
 */
int lod_def_striping_comp_resize(struct lod_default_striping *lds, __u16 count)
{
        struct lod_layout_component *entries;
        __u32 new = size_roundup_power2(sizeof(*lds->lds_def_comp_entries) *
                                        count);
        __u32 old = size_roundup_power2(sizeof(*lds->lds_def_comp_entries) *
                                        lds->lds_def_comp_size_cnt);

        if (new <= old)
                return 0;

        OBD_ALLOC_LARGE(entries, new);
        if (entries == NULL)
                return -ENOMEM;

        if (lds->lds_def_comp_entries != NULL) {
                CDEBUG(D_INFO, "default striping component size %d is not "
                       "enough, need %d\n", old, new);
                lod_free_def_comp_entries(lds);
        }

        lds->lds_def_comp_entries = entries;
        lds->lds_def_comp_size_cnt = count;

        RETURN(0);
}

void lod_free_comp_entries(struct lod_object *lo)
{
        if (lo->ldo_mirrors) {
                OBD_FREE_PTR_ARRAY(lo->ldo_mirrors, lo->ldo_mirror_count);
                lo->ldo_mirrors = NULL;
                lo->ldo_mirror_count = 0;
        }
        lod_free_comp_buffer(lo->ldo_comp_entries,
                             lo->ldo_comp_cnt,
                             sizeof(*lo->ldo_comp_entries) * lo->ldo_comp_cnt);
        lo->ldo_comp_entries = NULL;
        lo->ldo_comp_cnt = 0;
        lo->ldo_is_composite = 0;
}

int lod_alloc_comp_entries(struct lod_object *lo,
                           int mirror_count, int comp_count)
{
        LASSERT(comp_count != 0);
        LASSERT(lo->ldo_comp_cnt == 0 && lo->ldo_comp_entries == NULL);

        if (mirror_count > 0) {
                OBD_ALLOC_PTR_ARRAY(lo->ldo_mirrors, mirror_count);
                if (!lo->ldo_mirrors)
                        return -ENOMEM;

                lo->ldo_mirror_count = mirror_count;
        }

        OBD_ALLOC_LARGE(lo->ldo_comp_entries,
                        sizeof(*lo->ldo_comp_entries) * comp_count);
        if (lo->ldo_comp_entries == NULL) {
                OBD_FREE_PTR_ARRAY(lo->ldo_mirrors, mirror_count);
                lo->ldo_mirrors = NULL;
                lo->ldo_mirror_count = 0;
                return -ENOMEM;
        }

        lo->ldo_comp_cnt = comp_count;
        lo->ldo_is_foreign = 0;
        return 0;
}

int lod_fill_mirrors(struct lod_object *lo)
{
        struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct lod_layout_component *lod_comp;
        bool found_preferred = false;
        int mirror_idx = -1;
        __u16 mirror_id = 0xffff;
        int i, pref;
        ENTRY;

        LASSERT(equi(!lo->ldo_is_composite, lo->ldo_mirror_count == 0));

        if (!lo->ldo_is_composite)
                RETURN(0);

        lod_comp = &lo->ldo_comp_entries[0];

        for (i = 0; i < lo->ldo_comp_cnt; i++, lod_comp++) {
                bool stale = lod_comp->llc_flags & LCME_FL_STALE;
                bool preferred = lod_comp->llc_flags & LCME_FL_PREF_WR;
                bool mirror_hsm = lod_is_hsm(lod_comp);
                bool init = (lod_comp->llc_stripe != NULL) &&
                            !(lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED) &&
                            !(lod_comp->llc_pattern & LOV_PATTERN_MDT);
                int j;

                pref = 0;
                /* calculate component preference over all used OSTs */
                for (j = 0; init && j < lod_comp->llc_stripes_allocated; j++) {
                        __u32 idx = lod_comp->llc_ost_indices[j];
                        struct lod_tgt_desc *ltd;

                        if (lod_comp->llc_stripe[j] == NULL)
                                continue;

                        if (unlikely(idx >= lod->lod_ost_descs.ltd_tgts_size)) {
                                CERROR("%s: "DFID" OST idx %u > max %u\n",
                                       lod2obd(lod)->obd_name,
                                       PFID(lu_object_fid(&lo->ldo_obj.do_lu)),
                                       idx, lod->lod_ost_descs.ltd_tgts_size);
                                continue;
                        }
                        ltd = OST_TGT(lod, idx);
                        if (unlikely(!ltd)) {
                                CERROR("%s: "DFID" OST idx %u is NULL\n",
                                       lod2obd(lod)->obd_name,
                                       PFID(lu_object_fid(&lo->ldo_obj.do_lu)),
                                       idx);
                                continue;
                        }

                        if (ltd->ltd_statfs.os_state & OS_STATFS_NONROT)
                                pref++;
                }

                if (mirror_id_of(lod_comp->llc_id) == mirror_id) {
                        /* Currently HSM mirror does not support PFL. */
                        if (lo->ldo_mirrors[mirror_idx].lme_hsm)
                                RETURN(-EINVAL);
                        lo->ldo_mirrors[mirror_idx].lme_stale |= stale;
                        lo->ldo_mirrors[mirror_idx].lme_prefer |= preferred;
                        lo->ldo_mirrors[mirror_idx].lme_preference += pref;
                        lo->ldo_mirrors[mirror_idx].lme_end = i;
                        continue;
                }

                if (mirror_idx >= 0 && preferred &&
                    !lo->ldo_mirrors[mirror_idx].lme_stale)
                        found_preferred = true;

                /* new mirror */
                ++mirror_idx;
                if (mirror_idx >= lo->ldo_mirror_count)
                        RETURN(-EINVAL);

                if (mirror_hsm && (lod_comp->llc_extent.e_start != 0 ||
                                   lod_comp->llc_extent.e_end != LUSTRE_EOF))
                        RETURN(-EINVAL);

                mirror_id = mirror_id_of(lod_comp->llc_id);

                lo->ldo_mirrors[mirror_idx].lme_id = mirror_id;
                lo->ldo_mirrors[mirror_idx].lme_stale = stale;
                lo->ldo_mirrors[mirror_idx].lme_prefer = preferred;
                lo->ldo_mirrors[mirror_idx].lme_hsm = mirror_hsm;
                lo->ldo_mirrors[mirror_idx].lme_preference = pref;
                lo->ldo_mirrors[mirror_idx].lme_start = i;
                lo->ldo_mirrors[mirror_idx].lme_end = i;
        }
        if (mirror_idx != lo->ldo_mirror_count - 1)
                RETURN(-EINVAL);

        if (!found_preferred && mirror_idx > 0) {
                int best = -1;

                /*
                 * if no explicited preferred found, then find a mirror
                 * with higher number of non-rotational OSTs
                 * */
                pref = -1;
                for (i = 0; i <= mirror_idx; i++) {
                        if (lo->ldo_mirrors[i].lme_stale)
                                continue;
                        if (lo->ldo_mirrors[i].lme_preference > pref) {
                                pref = lo->ldo_mirrors[i].lme_preference;
                                best = i;
                        }
                }

                LASSERT(best >= 0);
                lo->ldo_mirrors[best].lme_prefer = 1;
        }

        RETURN(0);
}

/**
 * Generate on-disk lov_mds_md structure for each layout component based on
 * the information in lod_object->ldo_comp_entries[i].
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lo                LOD object
 * \param[in] comp_idx          index of ldo_comp_entries
 * \param[in] lmm               buffer to cotain the on-disk lov_mds_md
 * \param[in|out] lmm_size      buffer size/lmm size
 * \param[in] is_dir            generate lov ea for dir or file? For dir case,
 *                              the stripe info is from the default stripe
 *                              template, which is collected in lod_ah_init(),
 *                              either from parent object or root object; for
 *                              file case, it's from the @lo object
 *
 * \retval                      0 if on disk structure is created successfully
 * \retval                      negative error number on failure
 */
static int lod_gen_component_ea(const struct lu_env *env,
                                struct lod_object *lo, int comp_idx,
                                struct lov_mds_md *lmm, int *lmm_size,
                                bool is_dir)
{
        struct lod_thread_info  *info = lod_env_info(env);
        const struct lu_fid     *fid  = lu_object_fid(&lo->ldo_obj.do_lu);
        struct lod_device       *lod;
        struct lov_ost_data_v1  *objs;
        struct lod_layout_component *lod_comp;
        __u32   magic;
        __u16 stripe_count;
        int     i, rc = 0;
        ENTRY;

        LASSERT(lo);
        if (is_dir)
                lod_comp =
                        &lo->ldo_def_striping->lds_def_comp_entries[comp_idx];
        else
                lod_comp = &lo->ldo_comp_entries[comp_idx];

        magic = lod_comp->llc_pool != NULL ? LOV_MAGIC_V3 : LOV_MAGIC_V1;
        if (is_dir && lod_comp->llc_ostlist.op_count)
                magic = LOV_MAGIC_SPECIFIC;

        if (lod_comp->llc_pattern == 0) /* default striping */
                lod_comp->llc_pattern = LOV_PATTERN_RAID0;

        lmm->lmm_magic = cpu_to_le32(magic);
        lmm->lmm_pattern = cpu_to_le32(lod_comp->llc_pattern);
        fid_to_lmm_oi(fid, &lmm->lmm_oi);
        if (CFS_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_LMMOI))
                lmm->lmm_oi.oi.oi_id++;
        lmm_oi_cpu_to_le(&lmm->lmm_oi, &lmm->lmm_oi);

        lmm->lmm_stripe_size = cpu_to_le32(lod_comp->llc_stripe_size);
        lmm->lmm_stripe_count = cpu_to_le16(lod_comp->llc_stripe_count);
        /**
         * for dir and uninstantiated component, lmm_layout_gen stores
         * default stripe offset.
         */
        lmm->lmm_layout_gen =
                (is_dir || !lod_comp_inited(lod_comp)) ?
                        cpu_to_le16(lod_comp->llc_stripe_offset) :
                        cpu_to_le16(lod_comp->llc_layout_gen);

        if (magic == LOV_MAGIC_V1) {
                objs = &lmm->lmm_objects[0];
        } else {
                struct lov_mds_md_v3 *v3 = (struct lov_mds_md_v3 *)lmm;
                size_t cplen = strscpy(v3->lmm_pool_name,
                                       lod_comp->llc_pool ? : "\0",
                                       sizeof(v3->lmm_pool_name));
                if (cplen < 0)
                        RETURN(cplen);
                objs = &v3->lmm_objects[0];
        }
        lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        stripe_count = lod_comp_entry_stripe_count(lo, comp_idx, is_dir);
        if (stripe_count == 0 && !is_dir &&
            !(lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED) &&
            !(lod_comp->llc_pattern & LOV_PATTERN_MDT)) {
                /* Try again if all active targets are disconnected.
                 * It is possible when MDS does failover. */
                if (!lod->lod_ost_active_count &&
                    lod->lod_ost_count)
                        RETURN(-EAGAIN);
                RETURN(-E2BIG);
        }

        if (!is_dir && lo->ldo_is_composite)
                lod_comp_shrink_stripe_count(lod_comp, &stripe_count);

        if ((is_dir && magic != LOV_MAGIC_SPECIFIC) ||
            lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED)
                GOTO(done, rc = 0);

        /* generate ost_idx of this component stripe */
        for (i = 0; i < stripe_count; i++) {
                struct dt_object *object;
                __u32 ost_idx = (__u32)-1UL;
                int type = LU_SEQ_RANGE_OST;

                if (lod_comp->llc_stripe && lod_comp->llc_stripe[i]) {
                        object = lod_comp->llc_stripe[i];
                        /* instantiated component */
                        info->lti_fid = *lu_object_fid(&object->do_lu);

                        if (CFS_FAIL_CHECK(OBD_FAIL_LFSCK_MULTIPLE_REF) &&
                            comp_idx == 0) {
                                if (cfs_fail_val == 0)
                                        cfs_fail_val = info->lti_fid.f_oid;
                                else if (i == 0)
                                        info->lti_fid.f_oid = cfs_fail_val;
                        }

                        rc = fid_to_ostid(&info->lti_fid, &info->lti_ostid);
                        LASSERT(rc == 0);

                        ostid_cpu_to_le(&info->lti_ostid, &objs[i].l_ost_oi);
                        objs[i].l_ost_gen = cpu_to_le32(0);
                        if (CFS_FAIL_CHECK(OBD_FAIL_MDS_FLD_LOOKUP))
                                rc = -ENOENT;
                        else
                                rc = lod_fld_lookup(env, lod, &info->lti_fid,
                                                    &ost_idx, &type);
                        if (rc < 0) {
                                CERROR("%s: Can not locate "DFID": rc = %d\n",
                                       lod2obd(lod)->obd_name,
                                       PFID(&info->lti_fid), rc);
                                RETURN(rc);
                        }
                } else if (lod_comp->llc_ostlist.op_array &&
                           lod_comp->llc_ostlist.op_count) {
                        /* user specified ost list */
                        ost_idx = lod_comp->llc_ostlist.op_array[i];
                }
                /*
                 * with un-instantiated or with no specified ost list
                 * component, its l_ost_idx does not matter.
                 */
                objs[i].l_ost_idx = cpu_to_le32(ost_idx);

                /* simulation of broken LOVEA */
                if (CFS_FAIL_CHECK(OBD_FAIL_LOV_INVALID_OSTIDX) &&
                    comp_idx == 0 && i == 0 && lo->ldo_mirror_count > 1) {
                        objs[i].l_ost_idx = cpu_to_le32(0xffffffff);
                }

        }
done:
        if (lmm_size != NULL)
                *lmm_size = lov_mds_md_size(stripe_count, magic);
        RETURN(rc);
}

/**
 * Generate on-disk lov_hsm_md structure based on the information in
 * the lod_object->ldo_comp_entries.
 */
static int lod_gen_component_ea_foreign(const struct lu_env *env,
                                        struct lod_object *lo,
                                        struct lod_layout_component *lod_comp,
                                        void *lmm, int *lmm_size)
{
        struct lov_foreign_md *lfm = (struct lov_foreign_md *)lmm;

        ENTRY;

        lfm->lfm_magic = cpu_to_le32(LOV_MAGIC_FOREIGN);
        lfm->lfm_length = cpu_to_le32(lod_comp->llc_length);
        lfm->lfm_type = cpu_to_le32(lod_comp->llc_type);
        lfm->lfm_flags = cpu_to_le32(lod_comp->llc_foreign_flags);

        if (lov_hsm_type_supported(lod_comp->llc_type)) {
                if (lod_comp->llc_length != sizeof(struct lov_hsm_base))
                        return -EINVAL;

                lov_foreign_hsm_to_le(lfm, &lod_comp->llc_hsm);
        }

        if (lmm_size)
                *lmm_size = lov_foreign_md_size(lod_comp->llc_length);

        RETURN(0);
}

/**
 * Generate on-disk lov_mds_md structure based on the information in
 * the lod_object->ldo_comp_entries.
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lo                LOD object
 * \param[in] lmm               buffer to cotain the on-disk lov_mds_md
 * \param[in|out] lmm_size      buffer size/lmm size
 * \param[in] is_dir            generate lov ea for dir or file? For dir case,
 *                              the stripe info is from the default stripe
 *                              template, which is collected in lod_ah_init(),
 *                              either from parent object or root object; for
 *                              file case, it's from the @lo object
 *
 * \retval                      0 if on disk structure is created successfully
 * \retval                      negative error number on failure
 */
int lod_generate_lovea(const struct lu_env *env, struct lod_object *lo,
                       struct lov_mds_md *lmm, int *lmm_size, bool is_dir)
{
        struct lov_comp_md_entry_v1 *lcme;
        struct lov_comp_md_v1 *lcm;
        struct lod_layout_component *comp_entries;
        __u16 comp_cnt, mirror_cnt;
        bool is_composite, is_foreign = false;
        int i, rc = 0, offset;
        ENTRY;

        if (is_dir) {
                comp_cnt = lo->ldo_def_striping->lds_def_comp_cnt;
                mirror_cnt = lo->ldo_def_striping->lds_def_mirror_cnt;
                comp_entries = lo->ldo_def_striping->lds_def_comp_entries;
                is_composite =
                        lo->ldo_def_striping->lds_def_striping_is_composite;
        } else {
                comp_cnt = lo->ldo_comp_cnt;
                mirror_cnt = lo->ldo_mirror_count;
                comp_entries = lo->ldo_comp_entries;
                is_composite = lo->ldo_is_composite;
                is_foreign = lo->ldo_is_foreign;
        }

        LASSERT(lmm_size != NULL);

        if (is_foreign) {
                struct lov_foreign_md *lfm;

                lfm = (struct lov_foreign_md *)lmm;
                memcpy(lfm, lo->ldo_foreign_lov, lo->ldo_foreign_lov_size);
                /* need to store little-endian */
                if (cpu_to_le32(LOV_MAGIC_FOREIGN) != LOV_MAGIC_FOREIGN) {
                        __swab32s(&lfm->lfm_magic);
                        __swab32s(&lfm->lfm_length);
                        __swab32s(&lfm->lfm_type);
                        __swab32s(&lfm->lfm_flags);
                }
                *lmm_size = lo->ldo_foreign_lov_size;
                RETURN(0);
        }

        LASSERT(comp_cnt != 0 && comp_entries != NULL);

        if (!is_composite) {
                rc = lod_gen_component_ea(env, lo, 0, lmm, lmm_size, is_dir);
                RETURN(rc);
        }

        lcm = (struct lov_comp_md_v1 *)lmm;
        memset(lcm, 0, sizeof(*lcm));

        lcm->lcm_magic = cpu_to_le32(LOV_MAGIC_COMP_V1);
        lcm->lcm_entry_count = cpu_to_le16(comp_cnt);
        lcm->lcm_mirror_count = cpu_to_le16(mirror_cnt - 1);
        if (mirror_cnt > 1)
                lcm->lcm_flags = cpu_to_le16(lo->ldo_flr_state);
        else
                lcm->lcm_flags = LCM_FL_NONE;

        offset = sizeof(*lcm) + sizeof(*lcme) * comp_cnt;
        LASSERT(offset % sizeof(__u64) == 0);

        for (i = 0; i < comp_cnt; i++) {
                struct lod_layout_component *lod_comp;
                struct lov_mds_md *sub_md;
                int size;

                lod_comp = &comp_entries[i];
                lcme = &lcm->lcm_entries[i];

                LASSERT(ergo(!is_dir, lod_comp->llc_id != LCME_ID_INVAL));
                lcme->lcme_id = cpu_to_le32(lod_comp->llc_id);

                /* component could be un-inistantiated */
                lcme->lcme_flags = cpu_to_le32(lod_comp->llc_flags);
                if (lod_comp->llc_flags & LCME_FL_NOSYNC)
                        lcme->lcme_timestamp =
                                cpu_to_le64(lod_comp->llc_timestamp);
                if (lod_comp->llc_flags & LCME_FL_EXTENSION && !is_dir)
                        lcm->lcm_magic = cpu_to_le32(LOV_MAGIC_SEL);

                lcme->lcme_extent.e_start =
                        cpu_to_le64(lod_comp->llc_extent.e_start);
                lcme->lcme_extent.e_end =
                        cpu_to_le64(lod_comp->llc_extent.e_end);
                lcme->lcme_offset = cpu_to_le32(offset);

                sub_md = (struct lov_mds_md *)((char *)lcm + offset);
                if (lod_comp->llc_magic == LOV_MAGIC_FOREIGN) {
                        if (!lov_hsm_type_supported(lod_comp->llc_type)) {
                                CDEBUG(D_LAYOUT, "Unknown HSM type: %u\n",
                                       lod_comp->llc_type);
                                GOTO(out, rc = -EINVAL);
                        }
                        rc = lod_gen_component_ea_foreign(env, lo, lod_comp,
                                                          sub_md, &size);
                } else {
                        rc = lod_gen_component_ea(env, lo, i, sub_md,
                                                  &size, is_dir);
                }
                if (rc)
                        GOTO(out, rc);
                lcme->lcme_size = cpu_to_le32(size);
                offset += size;
                LASSERTF((offset <= *lmm_size) && (offset % sizeof(__u64) == 0),
                         "offset:%d lmm_size:%d\n", offset, *lmm_size);
        }
        lcm->lcm_size = cpu_to_le32(offset);
        lcm->lcm_layout_gen = cpu_to_le32(is_dir ? 0 : lo->ldo_layout_gen);

        lustre_print_user_md(D_LAYOUT, (struct lov_user_md *)lmm,
                             "generate lum");
out:
        if (rc == 0)
                *lmm_size = offset;
        RETURN(rc);
}

/**
 * Get LOV EA.
 *
 * Fill lti_ea_store buffer in the environment with a value for the given
 * EA. The buffer is reallocated if the value doesn't fit.
 *
 * \param[in,out] env           execution environment for this thread
 *                              .lti_ea_store buffer is filled with EA's value
 * \param[in] lo                LOD object
 * \param[in] name              name of the EA
 *
 * \retval                      > 0 if EA is fetched successfully
 * \retval                      0 if EA is empty
 * \retval                      negative error number on failure
 */
int lod_get_ea(const struct lu_env *env, struct lod_object *lo,
               const char *name)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct dt_object        *next = dt_object_child(&lo->ldo_obj);
        int rc, count = 0;
        ENTRY;

        LASSERT(info);

        if (unlikely(info->lti_ea_store == NULL)) {
                /* just to enter in allocation block below */
                rc = -ERANGE;
        } else {
repeat:
                info->lti_buf.lb_buf = info->lti_ea_store;
                info->lti_buf.lb_len = info->lti_ea_store_size;
                rc = dt_xattr_get(env, next, &info->lti_buf, name);
        }

        /* if object is not striped or inaccessible */
        if (rc == -ENODATA || rc == -ENOENT)
                RETURN(0);

        if (rc == -ERANGE) {
                /* EA doesn't fit, reallocate new buffer */
                rc = dt_xattr_get(env, next, &LU_BUF_NULL, name);
                if (rc == -ENODATA || rc == -ENOENT)
                        RETURN(0);
                else if (rc < 0)
                        RETURN(rc);

                LASSERT(rc > 0);
                if (rc <= info->lti_ea_store_size) {
                        /* sometimes LOVEA can shrink in parallel */
                        LASSERT(count++ < 10);
                        goto repeat;
                }
                rc = lod_ea_store_resize(info, rc);
                if (rc)
                        RETURN(rc);
                goto repeat;
        }

        RETURN(rc);
}

/**
 * Verify the target index is present in the current configuration.
 *
 * \param[in] md                LOD device where the target table is stored
 * \param[in] idx               target's index
 *
 * \retval                      0 if the index is present
 * \retval                      -EINVAL if not
 */
int validate_lod_and_idx(struct lod_device *md, __u32 idx)
{
        if (unlikely(idx >= md->lod_ost_descs.ltd_tgts_size ||
                     !test_bit(idx, md->lod_ost_bitmap))) {
                CERROR("%s: bad idx: %d of %d\n", lod2obd(md)->obd_name, idx,
                       md->lod_ost_descs.ltd_tgts_size);
                return -EINVAL;
        }

        if (unlikely(OST_TGT(md, idx) == NULL)) {
                CERROR("%s: bad lod_tgt_desc for idx: %d\n",
                       lod2obd(md)->obd_name, idx);
                return -EINVAL;
        }

        if (unlikely(OST_TGT(md, idx)->ltd_tgt == NULL)) {
                CERROR("%s: invalid lod device, for idx: %d\n",
                       lod2obd(md)->obd_name , idx);
                return -EINVAL;
        }

        return 0;
}

/**
 * Instantiate objects for stripes.
 *
 * Allocate and initialize LU-objects representing the stripes. The number
 * of the stripes (llc_stripe_count) must be initialized already. The caller
 * must ensure nobody else is calling the function on the object at the same
 * time. FLDB service must be running to be able to map a FID to the targets
 * and find appropriate device representing that target.
 *
 * \param[in] env               execution environment for this thread
 * \param[in,out] lo            LOD object
 * \param[in] objs              an array of IDs to creates the objects from
 * \param[in] comp_idx          index of ldo_comp_entries
 *
 * \retval                      0 if the objects are instantiated successfully
 * \retval                      negative error number on failure
 */
int lod_initialize_objects(const struct lu_env *env, struct lod_object *lo,
                           struct lov_ost_data_v1 *objs, int comp_idx)
{
        struct lod_layout_component *lod_comp;
        struct lod_thread_info *info = lod_env_info(env);
        struct lod_device *md;
        struct lu_object *o, *n;
        struct lu_device *nd;
        struct dt_object **stripe = NULL;
        __u32 *ost_indices = NULL;
        int stripe_len;
        int i, rc = 0;
        __u32 idx;
        ENTRY;

        LASSERT(lo != NULL);
        md = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);

        LASSERT(lo->ldo_comp_cnt != 0 && lo->ldo_comp_entries != NULL);
        lod_comp = &lo->ldo_comp_entries[comp_idx];

        LASSERT(lod_comp->llc_stripe == NULL);
        LASSERT(lod_comp->llc_stripe_count > 0);
        LASSERT(lod_comp->llc_stripe_size > 0);

        stripe_len = lod_comp->llc_stripe_count;
        OBD_ALLOC_PTR_ARRAY(stripe, stripe_len);
        if (stripe == NULL)
                RETURN(-ENOMEM);
        OBD_ALLOC_PTR_ARRAY(ost_indices, stripe_len);
        if (!ost_indices)
                GOTO(out, rc = -ENOMEM);

        for (i = 0; i < lod_comp->llc_stripe_count; i++) {
                if (unlikely(lovea_slot_is_dummy(&objs[i])))
                        continue;

                ostid_le_to_cpu(&objs[i].l_ost_oi, &info->lti_ostid);
                idx = le32_to_cpu(objs[i].l_ost_idx);
                rc = ostid_to_fid(&info->lti_fid, &info->lti_ostid, idx);
                if (rc != 0)
                        GOTO(out, rc);
                LASSERTF(fid_is_sane(&info->lti_fid), ""DFID" insane!\n",
                         PFID(&info->lti_fid));
                lod_getref(&md->lod_ost_descs);

                rc = validate_lod_and_idx(md, idx);
                if (unlikely(rc != 0)) {
                        lod_putref(md, &md->lod_ost_descs);
                        GOTO(out, rc);
                }

                nd = &OST_TGT(md, idx)->ltd_tgt->dd_lu_dev;
                lod_putref(md, &md->lod_ost_descs);

                /* In the function below, .hs_keycmp resolves to
                 * u_obj_hop_keycmp() */
                o = lu_object_find_at(env, nd, &info->lti_fid, NULL);
                if (IS_ERR(o))
                        GOTO(out, rc = PTR_ERR(o));

                n = lu_object_locate(o->lo_header, nd->ld_type);
                LASSERT(n);

                stripe[i] = container_of(n, struct dt_object, do_lu);
                ost_indices[i] = idx;
        }

out:
        if (rc != 0) {
                for (i = 0; i < stripe_len; i++)
                        if (stripe[i] != NULL)
                                dt_object_put(env, stripe[i]);

                OBD_FREE_PTR_ARRAY(stripe, stripe_len);
                lod_comp->llc_stripe_count = 0;
                if (ost_indices)
                        OBD_FREE_PTR_ARRAY(ost_indices, stripe_len);
        } else {
                lod_comp->llc_stripe = stripe;
                lod_comp->llc_ost_indices = ost_indices;
                lod_comp->llc_stripes_allocated = stripe_len;
        }

        RETURN(rc);
}

int lod_init_comp_foreign(struct lod_layout_component *lod_comp, void *lmm)
{
        struct lov_foreign_md *lfm;

        lfm = (struct lov_foreign_md *)lmm;
        lod_comp->llc_length = le32_to_cpu(lfm->lfm_length);
        lod_comp->llc_type = le32_to_cpu(lfm->lfm_type);

        if (!lov_hsm_type_supported(lod_comp->llc_type)) {
                CDEBUG(D_LAYOUT,
                       "Unsupport HSM type: %u length: %u flags: %08X\n",
                       lod_comp->llc_type, lod_comp->llc_length,
                       le32_to_cpu(lfm->lfm_flags));
                return -EINVAL;
        }

        /*
         * Currently it only stores the file FID as the field @lhm_archive_uuid
         * which is used to be the identifier within HSM backend for the archive
         * copy.
         * Thus the length of foreign layout value (HSM is a kind of foreign
         * layout type) is: sizeof(lhm_archive_id) + sizeof(lhm_archive_ver) +
         *                  UUID_MAX
         * It should fix to support other kinds of identifier for different HSM
         * solutions such as S3.
         */
        if (lod_comp->llc_length != sizeof(struct lov_hsm_base)) {
                CDEBUG(D_LAYOUT, "Invalid HSM len: %u, should be %zu\n",
                       lod_comp->llc_length, sizeof(struct lov_hsm_base));
                return -EINVAL;
        }

        lod_comp->llc_foreign_flags = le32_to_cpu(lfm->lfm_flags);
        lov_foreign_hsm_to_cpu(&lod_comp->llc_hsm, lfm);
        return 0;
}

/**
 * Instantiate objects for striping.
 *
 * Parse striping information in \a buf and instantiate the objects
 * representing the stripes.
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lo                LOD object
 * \param[in] buf               buffer storing LOV EA to parse
 * \param[in] lvf               verify flags when parsing the layout
 *
 * \retval                      0 if parsing and objects creation succeed
 * \retval                      negative error number on failure
 */
int lod_parse_striping(const struct lu_env *env, struct lod_object *lo,
                       const struct lu_buf *buf, enum layout_verify_flags lvf)
{
        struct lod_device *d = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct lov_mds_md_v1 *lmm;
        struct lov_comp_md_v1 *comp_v1 = NULL;
        struct lov_foreign_md *foreign = NULL;
        struct lov_ost_data_v1 *objs;
        __u32 magic, pattern;
        __u16 mirror_cnt = 0;
        __u16 comp_cnt;
        __u64 dom_size = 0;
        int i, rc;
        __u16 mirror_id = MIRROR_ID_NEG;
        bool stale = false;
        int stale_mirrors = 0;
        ENTRY;

        LASSERT(buf);
        LASSERT(buf->lb_buf);
        LASSERT(buf->lb_len);
        LASSERT(mutex_is_locked(&lo->ldo_layout_mutex));

        lmm = (struct lov_mds_md_v1 *)buf->lb_buf;
        magic = le32_to_cpu(lmm->lmm_magic);

        if (magic != LOV_MAGIC_V1 && magic != LOV_MAGIC_V3 &&
            magic != LOV_MAGIC_COMP_V1 && magic != LOV_MAGIC_FOREIGN &&
            magic != LOV_MAGIC_SEL)
                GOTO(out, rc = -EINVAL);

        lod_striping_free_nolock(env, lo);

        if (magic == LOV_MAGIC_COMP_V1 || magic == LOV_MAGIC_SEL) {
                comp_v1 = (struct lov_comp_md_v1 *)lmm;
                comp_cnt = le16_to_cpu(comp_v1->lcm_entry_count);
                if (comp_cnt == 0)
                        GOTO(out, rc = -EINVAL);

                lo->ldo_layout_gen = le32_to_cpu(comp_v1->lcm_layout_gen);
                lo->ldo_is_composite = 1;
                mirror_cnt = le16_to_cpu(comp_v1->lcm_mirror_count) + 1;
                if (mirror_cnt > 1)
                        lo->ldo_flr_state = le16_to_cpu(comp_v1->lcm_flags) &
                                                        LCM_FL_FLR_MASK;
                else
                        lo->ldo_flr_state = LCM_FL_NONE;
        } else if (magic == LOV_MAGIC_FOREIGN) {
                size_t length;

                foreign = (struct lov_foreign_md *)buf->lb_buf;
                length = offsetof(typeof(*foreign), lfm_value);
                if (buf->lb_len < length ||
                    buf->lb_len < (length + le32_to_cpu(foreign->lfm_length))) {
                        CDEBUG(D_LAYOUT,
                               "buf len %zu too small for lov_foreign_md\n",
                               buf->lb_len);
                        GOTO(out, rc = -EINVAL);
                }

                /* just cache foreign LOV EA raw */
                rc = lod_alloc_foreign_lov(lo, length);
                if (rc)
                        GOTO(out, rc);
                memcpy(lo->ldo_foreign_lov, buf->lb_buf, length);
                GOTO(out, rc);
        } else {
                comp_cnt = 1;
                lo->ldo_layout_gen = le16_to_cpu(lmm->lmm_layout_gen);
                lo->ldo_is_composite = 0;
        }

        rc = lod_alloc_comp_entries(lo, mirror_cnt, comp_cnt);
        if (rc)
                GOTO(out, rc);

        for (i = 0; i < comp_cnt; i++) {
                struct lod_layout_component *lod_comp;
                struct lu_extent *ext;
                __u32 offs;

                lod_comp = &lo->ldo_comp_entries[i];
                if (lo->ldo_is_composite) {
                        offs = le32_to_cpu(comp_v1->lcm_entries[i].lcme_offset);
                        lmm = (struct lov_mds_md_v1 *)((char *)comp_v1 + offs);

                        ext = &comp_v1->lcm_entries[i].lcme_extent;
                        lod_comp->llc_extent.e_start =
                                le64_to_cpu(ext->e_start);
                        if (lod_comp->llc_extent.e_start &
                            (LOV_MIN_STRIPE_SIZE - 1)) {
                                CDEBUG(D_LAYOUT,
                                       "extent start %llu is not a multiple of min size %u\n",
                                       lod_comp->llc_extent.e_start,
                                       LOV_MIN_STRIPE_SIZE);
                                GOTO(out, rc = -EINVAL);
                        }

                        lod_comp->llc_extent.e_end = le64_to_cpu(ext->e_end);
                        if (lod_comp->llc_extent.e_end != LUSTRE_EOF &&
                            lod_comp->llc_extent.e_end &
                            (LOV_MIN_STRIPE_SIZE - 1)) {
                                CDEBUG(D_LAYOUT,
                                       "extent end %llu is not a multiple of min size %u\n",
                                       lod_comp->llc_extent.e_end,
                                       LOV_MIN_STRIPE_SIZE);
                                GOTO(out, rc = -EINVAL);
                        }

                        lod_comp->llc_flags =
                                le32_to_cpu(comp_v1->lcm_entries[i].lcme_flags);

                        if (lod_comp->llc_flags & LCME_FL_NOSYNC)
                                lod_comp->llc_timestamp = le64_to_cpu(
                                        comp_v1->lcm_entries[i].lcme_timestamp);
                        lod_comp->llc_id =
                                le32_to_cpu(comp_v1->lcm_entries[i].lcme_id);
                        if (lod_comp->llc_id == LCME_ID_INVAL)
                                GOTO(out, rc = -EINVAL);

                        if (lvf & LVF_ALL_STALE) {
                                if (mirror_id_of(lod_comp->llc_id) ==
                                    mirror_id) {
                                        /* remaining comps in the mirror */
                                        stale |= lod_comp->llc_flags &
                                                 LCME_FL_STALE;
                                } else {
                                        /*
                                         * new mirror, check last mirror's
                                         * stale-ness
                                         */
                                        if (stale)
                                                stale_mirrors++;

                                        mirror_id =
                                                mirror_id_of(lod_comp->llc_id);

                                        /* the first comp of the new mirror */
                                        stale = lod_comp->llc_flags &
                                                LCME_FL_STALE;
                                }
                        }

                        if ((lod_comp->llc_flags & LCME_FL_EXTENSION) &&
                            comp_v1->lcm_magic != cpu_to_le32(LOV_MAGIC_SEL)) {
                                CWARN("%s: EXTENSION flags=%x set on component[%u]=%x of non-SEL file "DFID" with magic=%#08x\n",
                                      lod2obd(d)->obd_name,
                                      lod_comp->llc_flags, lod_comp->llc_id, i,
                                      PFID(lod_object_fid(lo)),
                                      le32_to_cpu(comp_v1->lcm_magic));
                        }

                        lod_comp->llc_magic = le32_to_cpu(lmm->lmm_magic);
                        if (lod_comp->llc_magic == LOV_MAGIC_FOREIGN) {
                                rc = lod_init_comp_foreign(lod_comp, lmm);
                                if (rc)
                                        GOTO(out, rc);
                                continue;
                        }
                } else {
                        lod_comp->llc_magic = le32_to_cpu(lmm->lmm_magic);
                        lod_comp_set_init(lod_comp);
                }

                pattern = le32_to_cpu(lmm->lmm_pattern);
                if (!lov_pattern_supported(lov_pattern(pattern)))
                        GOTO(out, rc = -EINVAL);

                if (pattern & LOV_PATTERN_MDT) {
                        if (lod_comp->llc_extent.e_start != 0) {
                                CERROR("%s: DOM entry must be the first stripe "
                                       "in a mirror\n", lod2obd(d)->obd_name);
                                GOTO(out, rc = -EINVAL);
                        }
                        if (!dom_size) {
                                dom_size = lod_comp->llc_extent.e_end;
                        } else if (dom_size != lod_comp->llc_extent.e_end) {
                                CERROR("%s: DOM entries with different sizes "
                                       "%#llx/%#llx\n", lod2obd(d)->obd_name,
                                       dom_size, lod_comp->llc_extent.e_end);
                                GOTO(out, rc = -EINVAL);
                        }
                }

                lod_comp->llc_pattern = pattern;
                lod_comp->llc_stripe_size = le32_to_cpu(lmm->lmm_stripe_size);
                lod_comp->llc_stripe_count = le16_to_cpu(lmm->lmm_stripe_count);
                lod_comp->llc_layout_gen = le16_to_cpu(lmm->lmm_layout_gen);

                if (lmm->lmm_magic == cpu_to_le32(LOV_MAGIC_V3)) {
                        struct lov_mds_md_v3 *v3 = (struct lov_mds_md_v3 *)lmm;

                        lod_set_pool(&lod_comp->llc_pool, v3->lmm_pool_name);
                        objs = &v3->lmm_objects[0];
                } else {
                        lod_set_pool(&lod_comp->llc_pool, NULL);
                        objs = &lmm->lmm_objects[0];
                }

                /**
                 * If uninstantiated template component has valid l_ost_idx,
                 * then user has specified ost list for this component.
                 */
                if (!lod_comp_inited(lod_comp)) {
                        __u16 stripe_count;

                        if (objs[0].l_ost_idx != (__u32)-1UL) {
                                int j;

                                stripe_count = lod_comp_entry_stripe_count(
                                                        lo, i, false);
                                if (stripe_count == 0 &&
                                    !(lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED) &&
                                    !(lod_comp->llc_pattern & LOV_PATTERN_MDT))
                                        GOTO(out, rc = -E2BIG);
                                /**
                                 * load the user specified ost list, when this
                                 * component is instantiated later, it will be
                                 * used in lod_alloc_ost_list().
                                 */
                                lod_comp->llc_ostlist.op_count = stripe_count;
                                lod_comp->llc_ostlist.op_size =
                                        stripe_count * sizeof(__u32);
                                OBD_ALLOC(lod_comp->llc_ostlist.op_array,
                                          lod_comp->llc_ostlist.op_size);
                                if (!lod_comp->llc_ostlist.op_array)
                                        GOTO(out, rc = -ENOMEM);

                                for (j = 0; j < stripe_count; j++)
                                        lod_comp->llc_ostlist.op_array[j] =
                                                le32_to_cpu(objs[j].l_ost_idx);

                                /**
                                 * this component OST objects starts from the
                                 * first ost_idx, lod_alloc_ost_list() will
                                 * check this.
                                 */
                                lod_comp->llc_stripe_offset = objs[0].l_ost_idx;
                        } else {
                                /**
                                 * for uninstantiated component,
                                 * lmm_layout_gen stores default stripe offset.
                                 */
                                lod_comp->llc_stripe_offset =
                                                        lmm->lmm_layout_gen;
                        }
                }

                /* skip un-instantiated component object initialization */
                if (!lod_comp_inited(lod_comp))
                        continue;

                if (!(lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED) &&
                    !(lod_comp->llc_pattern & LOV_PATTERN_MDT)) {
                        rc = lod_initialize_objects(env, lo, objs, i);
                        if (rc)
                                GOTO(out, rc);
                }
        }

        if (lo->ldo_is_composite && (lvf & LVF_ALL_STALE)) {
                /* check the last mirror stale-ness */
                if (stale)
                        stale_mirrors++;

                if (mirror_cnt == stale_mirrors) {
                        rc = -EPERM;
                        CERROR("%s: can not set all stale mirrors for "
                               DFID": rc = %d\n",
                               lod2obd(d)->obd_name, PFID(lod_object_fid(lo)),
                               rc);
                        GOTO(out, rc);
                }
        }

        rc = lod_fill_mirrors(lo);
        if (rc)
                GOTO(out, rc);

out:
        if (rc)
                lod_striping_free_nolock(env, lo);
        RETURN(rc);
}

/**
 * Check whether the striping (LOVEA for regular file, LMVEA for directory)
 * is already cached.
 *
 * \param[in] lo        LOD object
 *
 * \retval              True if the striping is cached, otherwise
 *                      return false.
 */
static bool lod_striping_loaded(struct lod_object *lo)
{
        if (S_ISREG(lod2lu_obj(lo)->lo_header->loh_attr) &&
            lo->ldo_comp_cached)
                return true;

        if (S_ISDIR(lod2lu_obj(lo)->lo_header->loh_attr)) {
                if (lo->ldo_dir_stripe_loaded)
                        return true;

                /* Never load LMV stripe for slaves of striped dir */
                if (lo->ldo_dir_slave_stripe)
                        return true;
        }

        return false;
}

/**
 * A generic function to initialize the stripe objects.
 *
 * A protected version of lod_striping_load_locked() - load the striping
 * information from storage, parse that and instantiate LU objects to
 * represent the stripes.  The LOD object \a lo supplies a pointer to the
 * next sub-object in the LU stack so we can lock it. Also use \a lo to
 * return an array of references to the newly instantiated objects.
 *
 * \param[in] env               execution environment for this thread
 * \param[in,out] lo            LOD object, where striping is stored and
 *                              which gets an array of references
 *
 * \retval                      0 if parsing and object creation succeed
 * \retval                      negative error number on failure
 **/
int lod_striping_load(const struct lu_env *env, struct lod_object *lo)
{
        struct lod_thread_info *info = lod_env_info(env);
        struct dt_object *next = dt_object_child(&lo->ldo_obj);
        struct lu_buf *buf = &info->lti_buf;
        int rc = 0;

        ENTRY;

        if (!dt_object_exists(next))
                RETURN(0);

        if (lod_striping_loaded(lo))
                RETURN(0);

        mutex_lock(&lo->ldo_layout_mutex);
        if (lod_striping_loaded(lo))
                GOTO(unlock, rc = 0);

        if (S_ISREG(lod2lu_obj(lo)->lo_header->loh_attr)) {
                rc = lod_get_lov_ea(env, lo);
                if (rc <= 0)
                        GOTO(unlock, rc);

                /*
                 * there is LOV EA (striping information) in this object
                 * let's parse it and create in-core objects for the stripes
                 */
                buf->lb_buf = info->lti_ea_store;
                buf->lb_len = info->lti_ea_store_size;
                rc = lod_parse_striping(env, lo, buf, 0);
                if (rc == 0)
                        lo->ldo_comp_cached = 1;
        } else if (S_ISDIR(lod2lu_obj(lo)->lo_header->loh_attr)) {
                rc = lod_get_lmv_ea(env, lo);

                if (rc > (int)sizeof(struct lmv_foreign_md)) {
                        struct lmv_foreign_md *lfm = info->lti_ea_store;

                        if (le32_to_cpu(lfm->lfm_magic) == LMV_MAGIC_FOREIGN) {
                                lo->ldo_foreign_lmv = info->lti_ea_store;
                                lo->ldo_foreign_lmv_size =
                                        info->lti_ea_store_size;
                                info->lti_ea_store = NULL;
                                info->lti_ea_store_size = 0;

                                lo->ldo_dir_stripe_loaded = 1;
                                lo->ldo_is_foreign = 1;
                                GOTO(unlock, rc = 0);
                        }
                }

                if (rc < (int)sizeof(struct lmv_mds_md_v1)) {
                        /* Let's set stripe_loaded to avoid further
                         * stripe loading especially for non-stripe directory,
                         * which can hurt performance. (See LU-9840)
                         */
                        if (rc == 0)
                                lo->ldo_dir_stripe_loaded = 1;
                        GOTO(unlock, rc = rc > 0 ? -EINVAL : rc);
                }
                buf->lb_buf = info->lti_ea_store;
                buf->lb_len = info->lti_ea_store_size;
                if (rc == sizeof(struct lmv_mds_md_v1)) {
                        rc = lod_load_lmv_shards(env, lo, buf, true);
                        if (buf->lb_buf != info->lti_ea_store) {
                                OBD_FREE_LARGE(info->lti_ea_store,
                                               info->lti_ea_store_size);
                                info->lti_ea_store = buf->lb_buf;
                                info->lti_ea_store_size = buf->lb_len;
                        }

                        if (rc < 0)
                                GOTO(unlock, rc);
                }

                /*
                 * there is LMV EA (striping information) in this object
                 * let's parse it and create in-core objects for the stripes
                 */
                rc = lod_parse_dir_striping(env, lo, buf);
                if (rc == 0)
                        lo->ldo_dir_stripe_loaded = 1;
        }
        EXIT;
unlock:
        mutex_unlock(&lo->ldo_layout_mutex);

        return rc;
}

int lod_striping_reload(const struct lu_env *env, struct lod_object *lo,
                        const struct lu_buf *buf, enum layout_verify_flags lvf)
{
        int rc;

        ENTRY;

        mutex_lock(&lo->ldo_layout_mutex);
        rc = lod_parse_striping(env, lo, buf, lvf);
        mutex_unlock(&lo->ldo_layout_mutex);

        RETURN(rc);
}

/**
 * Verify lov_user_md_v1/v3 striping.
 *
 * Check the validity of all fields including the magic, stripe size,
 * stripe count, stripe offset and that the pool is present.  Also check
 * that each target index points to an existing target. The additional
 * \a is_from_disk turns additional checks. In some cases zero fields
 * are allowed (like pattern=0).
 *
 * \param[in] d                 LOD device
 * \param[in] buf               buffer with LOV EA to verify
 * \param[in] is_from_disk      0 - from user, allow some fields to be 0
 *                              1 - from disk, do not allow
 *
 * \retval                      0 if the striping is valid
 * \retval                      -EINVAL if striping is invalid
 */
static int lod_verify_v1v3(struct lod_device *d, const struct lu_buf *buf,
                           bool is_from_disk)
{
        struct lov_user_md_v1   *lum;
        struct lov_user_md_v3   *lum3;
        struct lod_pool_desc    *pool = NULL;
        __u32                    magic;
        __u32                    stripe_size;
        __u16                    stripe_count;
        __u16                    stripe_offset;
        size_t                   lum_size;
        int                      rc = 0;
        ENTRY;

        lum = buf->lb_buf;

        if (buf->lb_len < sizeof(*lum)) {
                CDEBUG(D_LAYOUT, "buf len %zu too small for lov_user_md\n",
                       buf->lb_len);
                GOTO(out, rc = -EINVAL);
        }

        magic = le32_to_cpu(lum->lmm_magic) & ~LOV_MAGIC_DEFINED;
        if (magic != LOV_USER_MAGIC_V1 &&
            magic != LOV_USER_MAGIC_V3 &&
            magic != LOV_USER_MAGIC_SPECIFIC) {
                CDEBUG(D_LAYOUT, "bad userland LOV MAGIC: %#x\n",
                       le32_to_cpu(lum->lmm_magic));
                GOTO(out, rc = -EINVAL);
        }

        /* the user uses "0" for default stripe pattern normally. */
        if (!is_from_disk && lum->lmm_pattern == LOV_PATTERN_NONE)
                lum->lmm_pattern = cpu_to_le32(LOV_PATTERN_RAID0);

        if (!lov_pattern_supported(le32_to_cpu(lum->lmm_pattern))) {
                CDEBUG(D_LAYOUT, "bad userland stripe pattern: %#x\n",
                       le32_to_cpu(lum->lmm_pattern));
                GOTO(out, rc = -EINVAL);
        }

        /* a released lum comes from creating orphan on hsm release,
         * doesn't make sense to verify it. */
        if (le32_to_cpu(lum->lmm_pattern) & LOV_PATTERN_F_RELEASED)
                GOTO(out, rc = 0);

        /* 64kB is the largest common page size we see (ia64), and matches the
         * check in lfs */
        stripe_size = le32_to_cpu(lum->lmm_stripe_size);
        if (stripe_size & (LOV_MIN_STRIPE_SIZE - 1)) {
                CDEBUG(D_LAYOUT, "stripe size %u not a multiple of %u\n",
                       stripe_size, LOV_MIN_STRIPE_SIZE);
                GOTO(out, rc = -EINVAL);
        }

        stripe_offset = le16_to_cpu(lum->lmm_stripe_offset);
        if (!is_from_disk && stripe_offset != LOV_OFFSET_DEFAULT &&
            !(lov_pattern(le32_to_cpu(lum->lmm_pattern)) & LOV_PATTERN_MDT)) {
                /* if offset is not within valid range [0, osts_size) */
                if (stripe_offset >= d->lod_ost_descs.ltd_tgts_size) {
                        CDEBUG(D_LAYOUT, "stripe offset %u >= bitmap size %u\n",
                               stripe_offset, d->lod_ost_descs.ltd_tgts_size);
                        GOTO(out, rc = -EINVAL);
                }

                /* if lmm_stripe_offset is *not* in bitmap */
                if (!test_bit(stripe_offset, d->lod_ost_bitmap)) {
                        CDEBUG(D_LAYOUT, "stripe offset %u not in bitmap\n",
                               stripe_offset);
                        GOTO(out, rc = -EINVAL);
                }
        }

        if (magic == LOV_USER_MAGIC_V1)
                lum_size = offsetof(struct lov_user_md_v1,
                                    lmm_objects[0]);
        else if (magic == LOV_USER_MAGIC_V3 || magic == LOV_USER_MAGIC_SPECIFIC)
                lum_size = offsetof(struct lov_user_md_v3,
                                    lmm_objects[0]);
        else
                GOTO(out, rc = -EINVAL);

        stripe_count = le16_to_cpu(lum->lmm_stripe_count);
        if (buf->lb_len < lum_size) {
                CDEBUG(D_LAYOUT, "invalid buf len %zu/%zu for lov_user_md with "
                       "magic %#x and stripe_count %u\n",
                       buf->lb_len, lum_size, magic, stripe_count);
                GOTO(out, rc = -EINVAL);
        }

        if (!(magic == LOV_USER_MAGIC_V3 || magic == LOV_USER_MAGIC_SPECIFIC))
                goto out;

        lum3 = buf->lb_buf;
        /* In the function below, .hs_keycmp resolves to
         * pool_hashkey_keycmp() */
        pool = lod_find_pool(d, lum3->lmm_pool_name);
        if (pool == NULL)
                goto out;

        if (!is_from_disk && stripe_offset != LOV_OFFSET_DEFAULT) {
                rc = lod_check_index_in_pool(stripe_offset, pool);
                if (rc < 0)
                        GOTO(out, rc = -EINVAL);
        }

        if (is_from_disk && stripe_count > pool_tgt_count(pool)) {
                CDEBUG(D_LAYOUT, "stripe count %u > # OSTs %u in the pool\n",
                       stripe_count, pool_tgt_count(pool));
                GOTO(out, rc = -EINVAL);
        }

out:
        if (pool != NULL)
                lod_pool_putref(pool);

        RETURN(rc);
}

static inline
struct lov_comp_md_entry_v1 *comp_entry_v1(struct lov_comp_md_v1 *comp, int i)
{
        LASSERTF((le32_to_cpu(comp->lcm_magic) & ~LOV_MAGIC_DEFINED) ==
                 LOV_USER_MAGIC_COMP_V1 ||
                 (le32_to_cpu(comp->lcm_magic) & ~LOV_MAGIC_DEFINED) ==
                 LOV_USER_MAGIC_SEL, "Wrong magic %x\n",
                 le32_to_cpu(comp->lcm_magic));
        LASSERTF(i >= 0 && i < le16_to_cpu(comp->lcm_entry_count),
                 "bad index %d, max = %d\n",
                 i, le16_to_cpu(comp->lcm_entry_count));

        return &comp->lcm_entries[i];
}

#define for_each_comp_entry_v1(comp, entry) \
        for (entry = comp_entry_v1(comp, 0); \
             entry <= comp_entry_v1(comp, \
                                   le16_to_cpu(comp->lcm_entry_count) - 1); \
             entry++)

static int lod_erase_dom_stripe(struct lov_comp_md_v1 *comp_v1,
                                struct lov_comp_md_entry_v1 *dom_ent)
{
        struct lov_comp_md_entry_v1 *ent;
        __u16 entries;
        __u32 dom_off, dom_size, comp_size, off;
        void *src, *dst;
        unsigned int size, shift;

        entries = le16_to_cpu(comp_v1->lcm_entry_count) - 1;
        LASSERT(entries > 0);
        comp_v1->lcm_entry_count = cpu_to_le16(entries);

        comp_size = le32_to_cpu(comp_v1->lcm_size);
        dom_off = le32_to_cpu(dom_ent->lcme_offset);
        dom_size = le32_to_cpu(dom_ent->lcme_size);

        /* all entries offsets are shifted by entry size at least */
        shift = sizeof(*dom_ent);
        for_each_comp_entry_v1(comp_v1, ent) {
                off = le32_to_cpu(ent->lcme_offset);
                if (off == dom_off) {
                        /* Entry deletion creates two holes in layout data:
                         * - hole in entries array
                         * - hole in layout data at dom_off with dom_size
                         *
                         * First memmove is one entry shift from next entry
                         * start with size up to dom_off in blob
                         */
                        dst = (void *)ent;
                        src = (void *)(ent + 1);
                        size = (unsigned long)((void *)comp_v1 + dom_off - src);
                        memmove(dst, src, size);
                        /* take 'off' from just moved entry */
                        off = le32_to_cpu(ent->lcme_offset);
                        /* second memmove is blob tail after 'off' up to
                         * component end
                         */
                        dst = (void *)comp_v1 + dom_off - sizeof(*ent);
                        src = (void *)comp_v1 + off;
                        size = (unsigned long)(comp_size - off);
                        memmove(dst, src, size);
                        /* all entries offsets after DoM entry are shifted by
                         * dom_size additionally
                         */
                        shift += dom_size;
                }
                ent->lcme_offset = cpu_to_le32(off - shift);
        }
        comp_v1->lcm_size = cpu_to_le32(comp_size - shift);

        /* notify a caller to re-check entry */
        return -ERESTART;
}

void lod_dom_stripesize_recalc(struct lod_device *d)
{
        __u64 threshold_mb = d->lod_dom_threshold_free_mb;
        __u32 max_size = d->lod_dom_stripesize_max_kb;
        __u32 def_size = d->lod_dom_stripesize_cur_kb;

        /* use maximum allowed value if free space is above threshold */
        if (d->lod_lsfs_free_mb >= threshold_mb) {
                def_size = max_size;
        } else if (!d->lod_lsfs_free_mb || max_size <= LOD_DOM_MIN_SIZE_KB) {
                def_size = 0;
        } else {
                /* recalc threshold like it would be with def_size as max */
                threshold_mb = mult_frac(threshold_mb, def_size, max_size);
                if (d->lod_lsfs_free_mb < threshold_mb)
                        def_size = rounddown(def_size / 2, LOD_DOM_MIN_SIZE_KB);
                else if (d->lod_lsfs_free_mb > threshold_mb * 2)
                        def_size = max_t(unsigned int, def_size * 2,
                                         LOD_DOM_MIN_SIZE_KB);
        }

        if (d->lod_dom_stripesize_cur_kb != def_size) {
                CDEBUG(D_LAYOUT, "Change default DOM stripe size %d->%d\n",
                       d->lod_dom_stripesize_cur_kb, def_size);
                d->lod_dom_stripesize_cur_kb = def_size;
        }
}

static __u32 lod_dom_stripesize_limit(const struct lu_env *env,
                                      struct lod_device *d)
{
        int rc;

        /* set bfree as fraction of total space */
        if (CFS_FAIL_CHECK(OBD_FAIL_MDS_STATFS_SPOOF)) {
                spin_lock(&d->lod_lsfs_lock);
                d->lod_lsfs_free_mb = mult_frac(d->lod_lsfs_total_mb,
                                        min_t(int, cfs_fail_val, 100), 100);
                GOTO(recalc, rc = 0);
        }

        if (d->lod_lsfs_age < ktime_get_seconds() - LOD_DOM_SFS_MAX_AGE) {
                struct obd_statfs sfs;

                spin_lock(&d->lod_lsfs_lock);
                if (d->lod_lsfs_age > ktime_get_seconds() - LOD_DOM_SFS_MAX_AGE)
                        GOTO(unlock, rc = 0);

                d->lod_lsfs_age = ktime_get_seconds();
                spin_unlock(&d->lod_lsfs_lock);
                rc = dt_statfs(env, d->lod_child, &sfs);
                if (rc) {
                        CDEBUG(D_LAYOUT,
                               "%s: failed to get OSD statfs: rc = %d\n",
                               lod2obd(d)->obd_name, rc);
                        GOTO(out, rc);
                }
                /* udpate local OSD cached statfs data */
                spin_lock(&d->lod_lsfs_lock);
                d->lod_lsfs_total_mb = (sfs.os_blocks * sfs.os_bsize) >> 20;
                d->lod_lsfs_free_mb = (sfs.os_bfree * sfs.os_bsize) >> 20;
recalc:
                lod_dom_stripesize_recalc(d);
unlock:
                spin_unlock(&d->lod_lsfs_lock);
        }
out:
        return d->lod_dom_stripesize_cur_kb << 10;
}

static int lod_dom_stripesize_choose(const struct lu_env *env,
                                     struct lod_device *d,
                                     struct lov_comp_md_v1 *comp_v1,
                                     struct lov_comp_md_entry_v1 *dom_ent,
                                     __u32 stripe_size)
{
        struct lov_comp_md_entry_v1 *ent;
        struct lu_extent *dom_ext, *ext;
        struct lov_user_md_v1 *lum;
        __u32 max_stripe_size;
        __u16 mid, dom_mid;
        int rc = 0;
        bool dom_next_entry = false;

        dom_ext = &dom_ent->lcme_extent;
        dom_mid = mirror_id_of(le32_to_cpu(dom_ent->lcme_id));
        max_stripe_size = lod_dom_stripesize_limit(env, d);

        /* Check stripe size againts current per-MDT limit */
        if (stripe_size <= max_stripe_size)
                return 0;

        lum = (void *)comp_v1 + le32_to_cpu(dom_ent->lcme_offset);
        CDEBUG(D_LAYOUT, "overwrite DoM component size %u with MDT limit %u\n",
               stripe_size, max_stripe_size);
        lum->lmm_stripe_size = cpu_to_le32(max_stripe_size);

        /* In common case the DoM stripe is first entry in a mirror and
         * can be deleted only if it is not single entry in layout or
         * mirror, otherwise error should be returned.
         */
        for_each_comp_entry_v1(comp_v1, ent) {
                if (ent == dom_ent)
                        continue;

                mid = mirror_id_of(le32_to_cpu(ent->lcme_id));
                if (mid != dom_mid)
                        continue;

                ext = &ent->lcme_extent;
                if (ext->e_start != dom_ext->e_end)
                        continue;

                /* Found next component after the DoM one with the same
                 * mirror_id and adjust its start with DoM component end.
                 *
                 * NOTE: we are considering here that there can be only one
                 * DoM component in a file, all replicas are located on OSTs
                 * always and don't need adjustment since use own layouts.
                 */
                ext->e_start = cpu_to_le64(max_stripe_size);
                dom_next_entry = true;
                break;
        }

        if (max_stripe_size == 0) {
                /* DoM component size is zero due to server setting, remove
                 * it from the layout but only if next component exists in
                 * the same mirror. That must be checked prior calling the
                 * lod_erase_dom_stripe().
                 */
                if (!dom_next_entry)
                        return -EFBIG;

                rc = lod_erase_dom_stripe(comp_v1, dom_ent);
        } else {
                /* Update DoM extent end finally */
                dom_ext->e_end = cpu_to_le64(max_stripe_size);
        }

        return rc;
}

/**
 * Verify LOV striping.
 *
 * \param[in] d                 LOD device
 * \param[in] buf               buffer with LOV EA to verify
 * \param[in] is_from_disk      0 - from user, allow some fields to be 0
 *                              1 - from disk, do not allow
 * \param[in] start             extent start for composite layout
 *
 * \retval                      0 if the striping is valid
 * \retval                      -EINVAL if striping is invalid
 */
int lod_verify_striping(const struct lu_env *env, struct lod_device *d,
                        struct lod_object *lo, const struct lu_buf *buf,
                        bool is_from_disk)
{
        struct lov_user_md_v1   *lum;
        struct lov_comp_md_v1   *comp_v1;
        struct lov_comp_md_entry_v1     *ent;
        struct lu_extent        *ext;
        struct lu_buf   tmp;
        __u64   prev_end = 0;
        __u32   stripe_size = 0;
        __u16   prev_mid = -1, mirror_id = -1;
        __u32   mirror_count;
        __u32   magic;
        int     rc = 0;
        ENTRY;

        if (buf->lb_len < sizeof(lum->lmm_magic)) {
                CDEBUG(D_LAYOUT, "invalid buf len %zu\n", buf->lb_len);
                RETURN(-EINVAL);
        }

        lum = buf->lb_buf;

        magic = le32_to_cpu(lum->lmm_magic) & ~LOV_MAGIC_DEFINED;
        /* treat foreign LOV EA/object case first
         * XXX is it expected to try setting again a foreign?
         * XXX should we care about different current vs new layouts ?
         */
        if (unlikely(magic == LOV_USER_MAGIC_FOREIGN)) {
                struct lov_foreign_md *lfm = buf->lb_buf;

                if (buf->lb_len < offsetof(typeof(*lfm), lfm_value)) {
                        CDEBUG(D_LAYOUT,
                               "buf len %zu < min lov_foreign_md size (%zu)\n",
                               buf->lb_len, offsetof(typeof(*lfm),
                               lfm_value));
                        RETURN(-EINVAL);
                }

                if (lov_foreign_size_le(lfm) > buf->lb_len) {
                        CDEBUG(D_LAYOUT,
                               "buf len %zu < this lov_foreign_md size (%zu)\n",
                               buf->lb_len, lov_foreign_size_le(lfm));
                        RETURN(-EINVAL);
                }
                /* Don't do anything with foreign layouts */
                RETURN(0);
        }

        /* normal LOV/layout cases */

        if (buf->lb_len < sizeof(*lum)) {
                CDEBUG(D_LAYOUT, "buf len %zu too small for lov_user_md\n",
                       buf->lb_len);
                RETURN(-EINVAL);
        }

        switch (magic) {
        case LOV_USER_MAGIC_FOREIGN:
                RETURN(0);
        case LOV_USER_MAGIC_V1:
        case LOV_USER_MAGIC_V3:
        case LOV_USER_MAGIC_SPECIFIC:
                if (lov_pattern(le32_to_cpu(lum->lmm_pattern)) &
                    LOV_PATTERN_MDT) {
                        /* DoM must use composite layout */
                        CDEBUG(D_LAYOUT, "DoM without composite layout\n");
                        RETURN(-EINVAL);
                }
                RETURN(lod_verify_v1v3(d, buf, is_from_disk));
        case LOV_USER_MAGIC_COMP_V1:
        case LOV_USER_MAGIC_SEL:
                break;
        default:
                CDEBUG(D_LAYOUT, "bad userland LOV MAGIC: %#x\n",
                       le32_to_cpu(lum->lmm_magic));
                RETURN(-EINVAL);
        }

        /* magic == LOV_USER_MAGIC_COMP_V1 */
        comp_v1 = buf->lb_buf;
        if (buf->lb_len < le32_to_cpu(comp_v1->lcm_size)) {
                CDEBUG(D_LAYOUT, "buf len %zu is less than %u\n",
                       buf->lb_len, le32_to_cpu(comp_v1->lcm_size));
                RETURN(-EINVAL);
        }

recheck:
        mirror_count = 0;
        if (le16_to_cpu(comp_v1->lcm_entry_count) == 0) {
                CDEBUG(D_LAYOUT, "entry count is zero\n");
                RETURN(-EINVAL);
        }

        if (S_ISREG(lod2lu_obj(lo)->lo_header->loh_attr) &&
            lo->ldo_comp_cnt > 0) {
                /* could be called from lustre.lov.add */
                __u32 cnt = lo->ldo_comp_cnt;

                ext = &lo->ldo_comp_entries[cnt - 1].llc_extent;
                prev_end = ext->e_end;

                ++mirror_count;
        }

        for_each_comp_entry_v1(comp_v1, ent) {
                ext = &ent->lcme_extent;

                if (le64_to_cpu(ext->e_start) > le64_to_cpu(ext->e_end) ||
                    le64_to_cpu(ext->e_start) & (LOV_MIN_STRIPE_SIZE - 1) ||
                    ((__s64)le64_to_cpu(ext->e_start) < 0 &&
                    le64_to_cpu(ext->e_start) != LUSTRE_EOF) ||
                    (le64_to_cpu(ext->e_end) != LUSTRE_EOF &&
                    le64_to_cpu(ext->e_end) & (LOV_MIN_STRIPE_SIZE - 1)) ||
                    ((__s64)le64_to_cpu(ext->e_end) < 0 &&
                    le64_to_cpu(ext->e_end) != LUSTRE_EOF)) {
                        CDEBUG(D_LAYOUT, "invalid extent "DEXT"\n",
                               le64_to_cpu(ext->e_start),
                               le64_to_cpu(ext->e_end));
                        RETURN(-EINVAL);
                }

                if (is_from_disk) {
                        /* lcme_id contains valid value */
                        if (le32_to_cpu(ent->lcme_id) == 0 ||
                            le32_to_cpu(ent->lcme_id) > LCME_ID_MAX) {
                                CDEBUG(D_LAYOUT, "invalid id %u\n",
                                       le32_to_cpu(ent->lcme_id));
                                RETURN(-EINVAL);
                        }

                        if (le16_to_cpu(comp_v1->lcm_mirror_count) > 0) {
                                mirror_id = mirror_id_of(
                                                le32_to_cpu(ent->lcme_id));

                                /* first component must start with 0 */
                                if (mirror_id != prev_mid &&
                                    le64_to_cpu(ext->e_start) != 0) {
                                        CDEBUG(D_LAYOUT,
                                               "invalid start:%llu, expect:0\n",
                                               le64_to_cpu(ext->e_start));
                                        RETURN(-EINVAL);
                                }

                                prev_mid = mirror_id;
                        }
                }

                if (le64_to_cpu(ext->e_start) == 0) {
                        ++mirror_count;
                        prev_end = 0;
                }

                /* the next must be adjacent with the previous one */
                if (le64_to_cpu(ext->e_start) != prev_end) {
                        CDEBUG(D_LAYOUT,
                               "invalid start actual:%llu, expect:%llu\n",
                               le64_to_cpu(ext->e_start), prev_end);
                        RETURN(-EINVAL);
                }

                tmp.lb_buf = (char *)comp_v1 + le32_to_cpu(ent->lcme_offset);
                tmp.lb_len = le32_to_cpu(ent->lcme_size);

                lum = tmp.lb_buf;
                if (le32_to_cpu(lum->lmm_magic) == LOV_MAGIC_FOREIGN) {
                        struct lov_foreign_md *lfm;
                        struct lov_hsm_md *lhm;
                        u32 hsmsize;
                        u32 ftype;

                        /*
                         * Currently when the foreign layout is used as a basic
                         * layout component, it only supports HSM foreign types:
                         * LU_FOREIGN_TYPE_{POSIX, S3, PCCRW, PCCRO}.
                         */
                        lfm = (struct lov_foreign_md *)lum;
                        ftype = le32_to_cpu(lfm->lfm_type);
                        if (!lov_hsm_type_supported(ftype)) {
                                CDEBUG(D_LAYOUT,
                                       "Foreign type %#x is not HSM\n", ftype);
                                RETURN(-EINVAL);
                        }

                        /* Current HSM component must cover [0, EOF]. */
                        if (le64_to_cpu(ext->e_start) > 0) {
                                CDEBUG(D_LAYOUT, "Invalid HSM component with %llu extent start\n",
                                       le64_to_cpu(ext->e_start));
                                RETURN(-EINVAL);
                        }
                        if (le64_to_cpu(ext->e_end) != LUSTRE_EOF) {
                                CDEBUG(D_LAYOUT, "Invalid HSM component with %llu extent end\n",
                                       le64_to_cpu(ext->e_end));
                                RETURN(-EINVAL);
                        }

                        lhm = (struct lov_hsm_md *)lfm;
                        hsmsize = lov_foreign_size_le(lhm);

                        if (le32_to_cpu(lhm->lhm_length) !=
                            sizeof(struct lov_hsm_base)) {
                                CDEBUG(D_LAYOUT,
                                       "Invalid HSM component size %u != %u\n",
                                       le32_to_cpu(ent->lcme_size), hsmsize);
                                RETURN(-EINVAL);
                        }

                        if (le32_to_cpu(ent->lcme_size) < hsmsize) {
                                CDEBUG(D_LAYOUT,
                                       "Invalid HSM component size %u != %u\n",
                                       le32_to_cpu(ent->lcme_size), hsmsize);
                                RETURN(-EINVAL);
                        }
                        if (le32_to_cpu(lhm->lhm_flags) & ~HSM_FLAGS_MASK ||
                            !(le32_to_cpu(lhm->lhm_flags) & HSM_FLAGS_MASK)) {
                                CDEBUG(D_LAYOUT,
                                       "Invalid HSM component flags %#x\n",
                                       le32_to_cpu(lhm->lhm_flags));
                                RETURN(-EINVAL);
                        }
                        continue;
                }

                /* Check DoM entry is always the first one */
                if (lov_pattern(le32_to_cpu(lum->lmm_pattern)) &
                    LOV_PATTERN_MDT) {
                        /* DoM component must be the first in a mirror */
                        if (le64_to_cpu(ext->e_start) > 0) {
                                CDEBUG(D_LAYOUT, "invalid DoM component "
                                       "with %llu extent start\n",
                                       le64_to_cpu(ext->e_start));
                                RETURN(-EINVAL);
                        }
                        stripe_size = le32_to_cpu(lum->lmm_stripe_size);
                        /* There is just one stripe on MDT and it must
                         * cover whole component size. */
                        if (stripe_size != le64_to_cpu(ext->e_end)) {
                                CDEBUG(D_LAYOUT, "invalid DoM layout "
                                       "stripe size %u != %llu "
                                       "(component size)\n",
                                       stripe_size, prev_end);
                                RETURN(-EINVAL);
                        }
                        /* Check and adjust stripe size by per-MDT limit */
                        rc = lod_dom_stripesize_choose(env, d, comp_v1, ent,
                                                       stripe_size);
                        /* DoM entry was removed, re-check layout from start */
                        if (rc == -ERESTART)
                                goto recheck;
                        else if (rc)
                                RETURN(rc);

                        if (le16_to_cpu(lum->lmm_stripe_count) == 1)
                                lum->lmm_stripe_count = 0;
                        /* Any stripe count is forbidden on DoM component */
                        if (lum->lmm_stripe_count > 0) {
                                CDEBUG(D_LAYOUT,
                                       "invalid DoM layout stripe count %u, must be 0\n",
                                       le16_to_cpu(lum->lmm_stripe_count));
                                RETURN(-EINVAL);
                        }

                        /* Any pool is forbidden on DoM component */
                        if (lum->lmm_magic == LOV_USER_MAGIC_V3) {
                                struct lov_user_md_v3 *v3 = (void *)lum;

                                if (v3->lmm_pool_name[0] != '\0') {
                                        CDEBUG(D_LAYOUT,
                                               "DoM component cannot have pool assigned\n");
                                        RETURN(-EINVAL);
                                }
                        }
                }

                prev_end = le64_to_cpu(ext->e_end);

                rc = lod_verify_v1v3(d, &tmp, is_from_disk);
                if (rc)
                        RETURN(rc);

                if (prev_end == LUSTRE_EOF || ext->e_start == prev_end)
                        continue;

                /* extent end must be aligned with the stripe_size */
                stripe_size = le32_to_cpu(lum->lmm_stripe_size);
                if (stripe_size && prev_end % stripe_size) {
                        CDEBUG(D_LAYOUT, "stripe size isn't aligned, "
                               "stripe_sz: %u, [%llu, %llu)\n",
                               stripe_size, ext->e_start, prev_end);
                        RETURN(-EINVAL);
                }
        }

        /* make sure that the mirror_count is telling the truth */
        if (mirror_count != le16_to_cpu(comp_v1->lcm_mirror_count) + 1)
                RETURN(-EINVAL);

        RETURN(0);
}

/**
 * set the default stripe size, if unset.
 *
 * \param[in,out] val   number of bytes per OST stripe
 *
 * The minimum stripe size is 64KB to ensure that a single stripe is an
 * even multiple of a client PAGE_SIZE (IA64, PPC, etc).  Otherwise, it
 * is difficult to split dirty pages across OSCs during writes.
 */
void lod_fix_desc_stripe_size(__u64 *val)
{
        if (*val < LOV_MIN_STRIPE_SIZE) {
                if (*val != 0)
                        LCONSOLE_INFO("Increasing default stripe size to "
                                      "minimum value %u\n",
                                      LOV_DESC_STRIPE_SIZE_DEFAULT);
                *val = LOV_DESC_STRIPE_SIZE_DEFAULT;
        } else if (*val & (LOV_MIN_STRIPE_SIZE - 1)) {
                *val &= ~(LOV_MIN_STRIPE_SIZE - 1);
                LCONSOLE_WARN("Changing default stripe size to %llu (a "
                              "multiple of %u)\n",
                              *val, LOV_MIN_STRIPE_SIZE);
        }
}

/**
 * set the filesystem default number of stripes, if unset.
 *
 * \param[in,out] val   number of stripes
 *
 * A value of "0" means "use the system-wide default stripe count", which
 * has either been inherited by now, or falls back to 1 stripe per file.
 * A value of "-1" (0xffffffff) means "stripe over all available OSTs",
 * and is a valid value, so is left unchanged here.
 */
void lod_fix_desc_stripe_count(__u32 *val)
{
        if (*val == 0)
                *val = 1;
}

/**
 * set the filesystem default layout pattern
 *
 * \param[in,out] val   LOV_PATTERN_* layout
 *
 * A value of "0" means "use the system-wide default layout type", which
 * has either been inherited by now, or falls back to plain RAID0 striping.
 */
void lod_fix_desc_pattern(__u32 *val)
{
        /* from lov_setstripe */
        if ((*val != 0) && !lov_pattern_supported_normal_comp(*val)) {
                LCONSOLE_WARN("lod: Unknown stripe pattern: %#x\n", *val);
                *val = 0;
        }
}

void lod_fix_lmv_desc_pattern(__u32 *val)
{
        if ((*val) && !lmv_is_known_hash_type(*val)) {
                LCONSOLE_WARN("lod: Unknown md stripe pattern: %#x\n", *val);
                *val = 0;
        }
}

void lod_fix_desc_qos_maxage(__u32 *val)
{
        /* fix qos_maxage */
        if (*val == 0)
                *val = LOV_DESC_QOS_MAXAGE_DEFAULT;
}

/**
 * Used to fix insane default striping.
 *
 * \param[in] desc      striping description
 */
void lod_fix_desc(struct lov_desc *desc)
{
        lod_fix_desc_stripe_size(&desc->ld_default_stripe_size);
        lod_fix_desc_stripe_count(&desc->ld_default_stripe_count);
        lod_fix_desc_pattern(&desc->ld_pattern);
        lod_fix_desc_qos_maxage(&desc->ld_qos_maxage);
}

static void lod_fix_lmv_desc(struct lmv_desc *desc)
{
        desc->ld_active_tgt_count = 0;
        lod_fix_desc_stripe_count(&desc->ld_default_stripe_count);
        lod_fix_lmv_desc_pattern(&desc->ld_pattern);
        lod_fix_desc_qos_maxage(&desc->ld_qos_maxage);
}

/**
 * Initialize the structures used to store pools and default striping.
 *
 * \param[in] lod       LOD device
 * \param[in] lcfg      configuration structure storing default striping.
 *
 * \retval              0 if initialization succeeds
 * \retval              negative error number on failure
 */
int lod_pools_init(struct lod_device *lod, struct lustre_cfg *lcfg)
{
        struct obd_device          *obd;
        struct lov_desc            *desc;
        int                         rc;
        ENTRY;

        obd = class_name2obd(lustre_cfg_string(lcfg, 0));
        LASSERT(obd != NULL);
        obd->obd_lu_dev = &lod->lod_dt_dev.dd_lu_dev;

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

        desc = (struct lov_desc *)lustre_cfg_buf(lcfg, 1);

        if (sizeof(*desc) > LUSTRE_CFG_BUFLEN(lcfg, 1)) {
                CERROR("descriptor size wrong: %d > %d\n",
                       (int)sizeof(*desc), LUSTRE_CFG_BUFLEN(lcfg, 1));
                RETURN(-EINVAL);
        }

        if (desc->ld_magic != LOV_DESC_MAGIC) {
                if (desc->ld_magic == __swab32(LOV_DESC_MAGIC)) {
                        CDEBUG(D_OTHER, "%s: Swabbing lov desc %p\n",
                               obd->obd_name, desc);
                        lustre_swab_lov_desc(desc);
                } else {
                        CERROR("%s: Bad lov desc magic: %#x\n",
                               obd->obd_name, desc->ld_magic);
                        RETURN(-EINVAL);
                }
        }

        lod_fix_desc(desc);

        desc->ld_active_tgt_count = 0;
        lod->lod_ost_descs.ltd_lov_desc = *desc;

        /* NB: config doesn't contain lmv_desc, alter it via sysfs. */
        lod_fix_lmv_desc(&lod->lod_mdt_descs.ltd_lmv_desc);

        lod->lod_sp_me = LUSTRE_SP_CLI;

        /* Set up OST pool environment */
        lod->lod_pool_count = 0;
        rc = lod_pool_hash_init(&lod->lod_pools_hash_body);
        if (rc)
                RETURN(-ENOMEM);

        INIT_LIST_HEAD(&lod->lod_pool_list);
        lod->lod_pool_count = 0;
        rc = lu_tgt_pool_init(&lod->lod_mdt_descs.ltd_tgt_pool, 0);
        if (rc)
                GOTO(out_hash, rc);

        rc = lu_tgt_pool_init(&lod->lod_mdt_descs.ltd_qos.lq_rr.lqr_pool, 0);
        if (rc)
                GOTO(out_mdt_pool, rc);

        rc = lu_tgt_pool_init(&lod->lod_ost_descs.ltd_tgt_pool, 0);
        if (rc)
                GOTO(out_mdt_rr_pool, rc);

        rc = lu_tgt_pool_init(&lod->lod_ost_descs.ltd_qos.lq_rr.lqr_pool, 0);
        if (rc)
                GOTO(out_ost_pool, rc);

        RETURN(0);

out_ost_pool:
        lu_tgt_pool_free(&lod->lod_ost_descs.ltd_tgt_pool);
out_mdt_rr_pool:
        lu_tgt_pool_free(&lod->lod_mdt_descs.ltd_qos.lq_rr.lqr_pool);
out_mdt_pool:
        lu_tgt_pool_free(&lod->lod_mdt_descs.ltd_tgt_pool);
out_hash:
        lod_pool_hash_destroy(&lod->lod_pools_hash_body);

        return rc;
}

/**
 * Release the structures describing the pools.
 *
 * \param[in] lod       LOD device from which we release the structures
 *
 * \retval              0 always
 */
int lod_pools_fini(struct lod_device *lod)
{
        struct obd_device   *obd = lod2obd(lod);
        struct lod_pool_desc *pool, *tmp;
        ENTRY;

        list_for_each_entry_safe(pool, tmp, &lod->lod_pool_list, pool_list) {
                /* free pool structs */
                CDEBUG(D_INFO, "delete pool %p\n", pool);
                /* In the function below, .hs_keycmp resolves to
                 * pool_hashkey_keycmp() */
                lod_pool_del(obd, pool->pool_name);
        }

        lod_pool_hash_destroy(&lod->lod_pools_hash_body);
        lu_tgt_pool_free(&lod->lod_ost_descs.ltd_qos.lq_rr.lqr_pool);
        lu_tgt_pool_free(&lod->lod_ost_descs.ltd_tgt_pool);
        lu_tgt_pool_free(&lod->lod_mdt_descs.ltd_qos.lq_rr.lqr_pool);
        lu_tgt_pool_free(&lod->lod_mdt_descs.ltd_tgt_pool);

        RETURN(0);
}