LU-4974 lod: documentation for lod_object.c

[fs/lustre-release.git] / lustre / lod / lod_object.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
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * GPL HEADER END
 */
/*
 * Copyright  2009 Sun Microsystems, Inc. All rights reserved
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2013, Intel Corporation.
 */
/*
 * lustre/lod/lod_object.c
 *
 * This file contains implementations of methods for the OSD API
 * for the Logical Object Device (LOD) layer, which provides a virtual
 * local OSD object interface to the MDD layer, and abstracts the
 * addressing of local (OSD) and remote (OSP) objects. The API is
 * described in the file lustre/include/dt_object.h and in
 * lustre/doc/osd-api.txt.
 *
 * Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
 */

#define DEBUG_SUBSYSTEM S_MDS

#include <obd.h>
#include <obd_class.h>
#include <lustre_ver.h>
#include <obd_support.h>
#include <lprocfs_status.h>

#include <lustre_fid.h>
#include <lustre_param.h>
#include <lustre_fid.h>
#include <lustre_lmv.h>
#include <md_object.h>
#include <lustre_linkea.h>

#include "lod_internal.h"

static const char dot[] = ".";
static const char dotdot[] = "..";

extern struct kmem_cache *lod_object_kmem;
static const struct dt_body_operations lod_body_lnk_ops;

/**
 * Implementation of dt_index_operations::dio_lookup
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_index_operations::dio_lookup() in the API description for details.
 */
static int lod_index_lookup(const struct lu_env *env, struct dt_object *dt,
                            struct dt_rec *rec, const struct dt_key *key,
                            struct lustre_capa *capa)
{
        struct dt_object *next = dt_object_child(dt);
        return next->do_index_ops->dio_lookup(env, next, rec, key, capa);
}

/**
 * Implementation of dt_index_operations::dio_declare_insert.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_index_operations::dio_declare_insert() in the API description
 * for details.
 */
static int lod_declare_index_insert(const struct lu_env *env,
                                    struct dt_object *dt,
                                    const struct dt_rec *rec,
                                    const struct dt_key *key,
                                    struct thandle *handle)
{
        return dt_declare_insert(env, dt_object_child(dt), rec, key, handle);
}

/**
 * Implementation of dt_index_operations::dio_insert.
 *
 * Used with regular (non-striped) objects
 *
 * \see dt_index_operations::dio_insert() in the API description for details.
 */
static int lod_index_insert(const struct lu_env *env,
                            struct dt_object *dt,
                            const struct dt_rec *rec,
                            const struct dt_key *key,
                            struct thandle *th,
                            struct lustre_capa *capa,
                            int ign)
{
        return dt_insert(env, dt_object_child(dt), rec, key, th, capa, ign);
}

/**
 * Implementation of dt_index_operations::dio_declare_delete.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_index_operations::dio_declare_delete() in the API description
 * for details.
 */
static int lod_declare_index_delete(const struct lu_env *env,
                                    struct dt_object *dt,
                                    const struct dt_key *key,
                                    struct thandle *th)
{
        return dt_declare_delete(env, dt_object_child(dt), key, th);
}

/**
 * Implementation of dt_index_operations::dio_delete.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_index_operations::dio_delete() in the API description for details.
 */
static int lod_index_delete(const struct lu_env *env,
                            struct dt_object *dt,
                            const struct dt_key *key,
                            struct thandle *th,
                            struct lustre_capa *capa)
{
        return dt_delete(env, dt_object_child(dt), key, th, capa);
}

/**
 * Implementation of dt_it_ops::init.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::init() in the API description for details.
 */
static struct dt_it *lod_it_init(const struct lu_env *env,
                                 struct dt_object *dt, __u32 attr,
                                 struct lustre_capa *capa)
{
        struct dt_object        *next = dt_object_child(dt);
        struct lod_it           *it = &lod_env_info(env)->lti_it;
        struct dt_it            *it_next;


        it_next = next->do_index_ops->dio_it.init(env, next, attr, capa);
        if (IS_ERR(it_next))
                return it_next;

        /* currently we do not use more than one iterator per thread
         * so we store it in thread info. if at some point we need
         * more active iterators in a single thread, we can allocate
         * additional ones */
        LASSERT(it->lit_obj == NULL);

        it->lit_it = it_next;
        it->lit_obj = next;

        return (struct dt_it *)it;
}

#define LOD_CHECK_IT(env, it)                                   \
do {                                                            \
        LASSERT((it)->lit_obj != NULL);                         \
        LASSERT((it)->lit_it != NULL);                          \
} while (0)

/**
 * Implementation of dt_index_operations::dio_it.fini.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_index_operations::dio_it.fini() in the API description for details.
 */
void lod_it_fini(const struct lu_env *env, struct dt_it *di)
{
        struct lod_it *it = (struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        it->lit_obj->do_index_ops->dio_it.fini(env, it->lit_it);

        /* the iterator not in use any more */
        it->lit_obj = NULL;
        it->lit_it = NULL;
}

/**
 * Implementation of dt_it_ops::get.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::get() in the API description for details.
 */
int lod_it_get(const struct lu_env *env, struct dt_it *di,
               const struct dt_key *key)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.get(env, it->lit_it, key);
}

/**
 * Implementation of dt_it_ops::put.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::put() in the API description for details.
 */
void lod_it_put(const struct lu_env *env, struct dt_it *di)
{
        struct lod_it *it = (struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.put(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::next.
 *
 * Used with regular (non-striped) objects
 *
 * \see dt_it_ops::next() in the API description for details.
 */
int lod_it_next(const struct lu_env *env, struct dt_it *di)
{
        struct lod_it *it = (struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.next(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::key.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::key() in the API description for details.
 */
struct dt_key *lod_it_key(const struct lu_env *env, const struct dt_it *di)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.key(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::key_size.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::key_size() in the API description for details.
 */
int lod_it_key_size(const struct lu_env *env, const struct dt_it *di)
{
        struct lod_it *it = (struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.key_size(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::rec.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::rec() in the API description for details.
 */
int lod_it_rec(const struct lu_env *env, const struct dt_it *di,
               struct dt_rec *rec, __u32 attr)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.rec(env, it->lit_it, rec,
                                                     attr);
}

/**
 * Implementation of dt_it_ops::rec_size.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::rec_size() in the API description for details.
 */
int lod_it_rec_size(const struct lu_env *env, const struct dt_it *di,
                    __u32 attr)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.rec_size(env, it->lit_it,
                                                          attr);
}

/**
 * Implementation of dt_it_ops::store.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::store() in the API description for details.
 */
__u64 lod_it_store(const struct lu_env *env, const struct dt_it *di)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.store(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::load.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::load() in the API description for details.
 */
int lod_it_load(const struct lu_env *env, const struct dt_it *di, __u64 hash)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.load(env, it->lit_it, hash);
}

/**
 * Implementation of dt_it_ops::key_rec.
 *
 * Used with regular (non-striped) objects.
 *
 * \see dt_it_ops::rec() in the API description for details.
 */
int lod_it_key_rec(const struct lu_env *env, const struct dt_it *di,
                   void *key_rec)
{
        const struct lod_it *it = (const struct lod_it *)di;

        LOD_CHECK_IT(env, it);
        return it->lit_obj->do_index_ops->dio_it.key_rec(env, it->lit_it,
                                                         key_rec);
}

static struct dt_index_operations lod_index_ops = {
        .dio_lookup             = lod_index_lookup,
        .dio_declare_insert     = lod_declare_index_insert,
        .dio_insert             = lod_index_insert,
        .dio_declare_delete     = lod_declare_index_delete,
        .dio_delete             = lod_index_delete,
        .dio_it = {
                .init           = lod_it_init,
                .fini           = lod_it_fini,
                .get            = lod_it_get,
                .put            = lod_it_put,
                .next           = lod_it_next,
                .key            = lod_it_key,
                .key_size       = lod_it_key_size,
                .rec            = lod_it_rec,
                .rec_size       = lod_it_rec_size,
                .store          = lod_it_store,
                .load           = lod_it_load,
                .key_rec        = lod_it_key_rec,
        }
};

/**
 * Implementation of dt_it_ops::init.
 *
 * Used with striped objects. Internally just initializes the iterator
 * on the first stripe.
 *
 * \see dt_it_ops::init() in the API description for details.
 */
static struct dt_it *lod_striped_it_init(const struct lu_env *env,
                                         struct dt_object *dt, __u32 attr,
                                         struct lustre_capa *capa)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct dt_object        *next;
        struct lod_it           *it = &lod_env_info(env)->lti_it;
        struct dt_it            *it_next;
        ENTRY;

        LASSERT(lo->ldo_stripenr > 0);
        next = lo->ldo_stripe[0];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        it_next = next->do_index_ops->dio_it.init(env, next, attr, capa);
        if (IS_ERR(it_next))
                return it_next;

        /* currently we do not use more than one iterator per thread
         * so we store it in thread info. if at some point we need
         * more active iterators in a single thread, we can allocate
         * additional ones */
        LASSERT(it->lit_obj == NULL);

        it->lit_stripe_index = 0;
        it->lit_attr = attr;
        it->lit_it = it_next;
        it->lit_obj = dt;

        return (struct dt_it *)it;
}

#define LOD_CHECK_STRIPED_IT(env, it, lo)                       \
do {                                                            \
        LASSERT((it)->lit_obj != NULL);                         \
        LASSERT((it)->lit_it != NULL);                          \
        LASSERT((lo)->ldo_stripenr > 0);                        \
        LASSERT((it)->lit_stripe_index < (lo)->ldo_stripenr);   \
} while (0)

/**
 * Implementation of dt_it_ops::fini.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::fini() in the API description for details.
 */
static void lod_striped_it_fini(const struct lu_env *env, struct dt_it *di)
{
        struct lod_it           *it = (struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        next->do_index_ops->dio_it.fini(env, it->lit_it);

        /* the iterator not in use any more */
        it->lit_obj = NULL;
        it->lit_it = NULL;
        it->lit_stripe_index = 0;
}

/**
 * Implementation of dt_it_ops::get.
 *
 * Right now it's not used widely, only to reset the iterator to the
 * initial position. It should be possible to implement a full version
 * which chooses a correct stripe to be able to position with any key.
 *
 * \see dt_it_ops::get() in the API description for details.
 */
static int lod_striped_it_get(const struct lu_env *env, struct dt_it *di,
                              const struct dt_key *key)
{
        const struct lod_it     *it = (const struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;
        ENTRY;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.get(env, it->lit_it, key);
}

/**
 * Implementation of dt_it_ops::put.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::put() in the API description for details.
 */
static void lod_striped_it_put(const struct lu_env *env, struct dt_it *di)
{
        struct lod_it           *it = (struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.put(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::next.
 *
 * Used with striped objects. When the end of the current stripe is
 * reached, the method takes the next stripe's iterator.
 *
 * \see dt_it_ops::next() in the API description for details.
 */
static int lod_striped_it_next(const struct lu_env *env, struct dt_it *di)
{
        struct lod_it           *it = (struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;
        struct dt_it            *it_next;
        int                     rc;
        ENTRY;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);
again:
        rc = next->do_index_ops->dio_it.next(env, it->lit_it);
        if (rc < 0)
                RETURN(rc);

        if (rc == 0 && it->lit_stripe_index == 0)
                RETURN(rc);

        if (rc == 0 && it->lit_stripe_index > 0) {
                struct lu_dirent *ent;

                ent = (struct lu_dirent *)lod_env_info(env)->lti_key;

                rc = next->do_index_ops->dio_it.rec(env, it->lit_it,
                                                    (struct dt_rec *)ent,
                                                    it->lit_attr);
                if (rc != 0)
                        RETURN(rc);

                /* skip . and .. for slave stripe */
                if ((strncmp(ent->lde_name, ".",
                             le16_to_cpu(ent->lde_namelen)) == 0 &&
                     le16_to_cpu(ent->lde_namelen) == 1) ||
                    (strncmp(ent->lde_name, "..",
                             le16_to_cpu(ent->lde_namelen)) == 0 &&
                     le16_to_cpu(ent->lde_namelen) == 2))
                        goto again;

                RETURN(rc);
        }

        /* go to next stripe */
        if (it->lit_stripe_index + 1 >= lo->ldo_stripenr)
                RETURN(1);

        it->lit_stripe_index++;

        next->do_index_ops->dio_it.put(env, it->lit_it);
        next->do_index_ops->dio_it.fini(env, it->lit_it);

        rc = next->do_ops->do_index_try(env, next, &dt_directory_features);
        if (rc != 0)
                RETURN(rc);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        it_next = next->do_index_ops->dio_it.init(env, next, it->lit_attr,
                                                  BYPASS_CAPA);
        if (!IS_ERR(it_next)) {
                it->lit_it = it_next;
                goto again;
        } else {
                rc = PTR_ERR(it_next);
        }

        RETURN(rc);
}

/**
 * Implementation of dt_it_ops::key.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::key() in the API description for details.
 */
static struct dt_key *lod_striped_it_key(const struct lu_env *env,
                                         const struct dt_it *di)
{
        const struct lod_it     *it = (const struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.key(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::key_size.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::size() in the API description for details.
 */
static int lod_striped_it_key_size(const struct lu_env *env,
                                   const struct dt_it *di)
{
        struct lod_it           *it = (struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.key_size(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::rec.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::rec() in the API description for details.
 */
static int lod_striped_it_rec(const struct lu_env *env, const struct dt_it *di,
                              struct dt_rec *rec, __u32 attr)
{
        const struct lod_it     *it = (const struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.rec(env, it->lit_it, rec, attr);
}

/**
 * Implementation of dt_it_ops::rec_size.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::rec_size() in the API description for details.
 */
static int lod_striped_it_rec_size(const struct lu_env *env,
                                   const struct dt_it *di, __u32 attr)
{
        struct lod_it           *it = (struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.rec_size(env, it->lit_it, attr);
}

/**
 * Implementation of dt_it_ops::store.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::store() in the API description for details.
 */
static __u64 lod_striped_it_store(const struct lu_env *env,
                                  const struct dt_it *di)
{
        const struct lod_it     *it = (const struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.store(env, it->lit_it);
}

/**
 * Implementation of dt_it_ops::load.
 *
 * Used with striped objects.
 *
 * \see dt_it_ops::load() in the API description for details.
 */
static int lod_striped_it_load(const struct lu_env *env,
                               const struct dt_it *di, __u64 hash)
{
        const struct lod_it     *it = (const struct lod_it *)di;
        struct lod_object       *lo = lod_dt_obj(it->lit_obj);
        struct dt_object        *next;

        LOD_CHECK_STRIPED_IT(env, it, lo);

        next = lo->ldo_stripe[it->lit_stripe_index];
        LASSERT(next != NULL);
        LASSERT(next->do_index_ops != NULL);

        return next->do_index_ops->dio_it.load(env, it->lit_it, hash);
}

static struct dt_index_operations lod_striped_index_ops = {
        .dio_lookup             = lod_index_lookup,
        .dio_declare_insert     = lod_declare_index_insert,
        .dio_insert             = lod_index_insert,
        .dio_declare_delete     = lod_declare_index_delete,
        .dio_delete             = lod_index_delete,
        .dio_it = {
                .init           = lod_striped_it_init,
                .fini           = lod_striped_it_fini,
                .get            = lod_striped_it_get,
                .put            = lod_striped_it_put,
                .next           = lod_striped_it_next,
                .key            = lod_striped_it_key,
                .key_size       = lod_striped_it_key_size,
                .rec            = lod_striped_it_rec,
                .rec_size       = lod_striped_it_rec_size,
                .store          = lod_striped_it_store,
                .load           = lod_striped_it_load,
        }
};

/**
 * Append the FID for each shard of the striped directory after the
 * given LMV EA header.
 *
 * To simplify striped directory and the consistency verification,
 * we only store the LMV EA header on disk, for both master object
 * and slave objects. When someone wants to know the whole LMV EA,
 * such as client readdir(), we can build the entrie LMV EA on the
 * MDT side (in RAM) via iterating the sub-directory entries that
 * are contained in the master object of the stripe directory.
 *
 * For the master object of the striped directroy, the valid name
 * for each shard is composed of the ${shard_FID}:${shard_idx}.
 *
 * There may be holes in the LMV EA if some shards' name entries
 * are corrupted or lost.
 *
 * \param[in] env       pointer to the thread context
 * \param[in] lo        pointer to the master object of the striped directory
 * \param[in] buf       pointer to the lu_buf which will hold the LMV EA
 * \param[in] resize    whether re-allocate the buffer if it is not big enough
 *
 * \retval              positive size of the LMV EA
 * \retval              0 for nothing to be loaded
 * \retval              negative error number on failure
 */
int lod_load_lmv_shards(const struct lu_env *env, struct lod_object *lo,
                        struct lu_buf *buf, bool resize)
{
        struct lu_dirent        *ent    =
                        (struct lu_dirent *)lod_env_info(env)->lti_key;
        struct lod_device       *lod    = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct dt_object        *obj    = dt_object_child(&lo->ldo_obj);
        struct lmv_mds_md_v1    *lmv1   = buf->lb_buf;
        struct dt_it            *it;
        const struct dt_it_ops  *iops;
        __u32                    stripes;
        __u32                    magic  = le32_to_cpu(lmv1->lmv_magic);
        size_t                   lmv1_size;
        int                      rc;
        ENTRY;

        /* If it is not a striped directory, then load nothing. */
        if (magic != LMV_MAGIC_V1)
                RETURN(0);

        /* If it is in migration (or failure), then load nothing. */
        if (le32_to_cpu(lmv1->lmv_hash_type) & LMV_HASH_FLAG_MIGRATION)
                RETURN(0);

        stripes = le32_to_cpu(lmv1->lmv_stripe_count);
        if (stripes < 1)
                RETURN(0);

        rc = lmv_mds_md_size(stripes, magic);
        if (rc < 0)
                RETURN(rc);
        lmv1_size = rc;
        if (buf->lb_len < lmv1_size) {
                struct lu_buf tbuf;

                if (!resize)
                        RETURN(-ERANGE);

                tbuf = *buf;
                buf->lb_buf = NULL;
                buf->lb_len = 0;
                lu_buf_alloc(buf, lmv1_size);
                lmv1 = buf->lb_buf;
                if (lmv1 == NULL)
                        RETURN(-ENOMEM);

                memcpy(buf->lb_buf, tbuf.lb_buf, tbuf.lb_len);
        }

        if (unlikely(!dt_try_as_dir(env, obj)))
                RETURN(-ENOTDIR);

        memset(&lmv1->lmv_stripe_fids[0], 0, stripes * sizeof(struct lu_fid));
        iops = &obj->do_index_ops->dio_it;
        it = iops->init(env, obj, LUDA_64BITHASH, BYPASS_CAPA);
        if (IS_ERR(it))
                RETURN(PTR_ERR(it));

        rc = iops->load(env, it, 0);
        if (rc == 0)
                rc = iops->next(env, it);
        else if (rc > 0)
                rc = 0;

        while (rc == 0) {
                char             name[FID_LEN + 2] = "";
                struct lu_fid    fid;
                __u32            index;
                int              len;

                rc = iops->rec(env, it, (struct dt_rec *)ent, LUDA_64BITHASH);
                if (rc != 0)
                        break;

                rc = -EIO;

                fid_le_to_cpu(&fid, &ent->lde_fid);
                ent->lde_namelen = le16_to_cpu(ent->lde_namelen);
                if (ent->lde_name[0] == '.') {
                        if (ent->lde_namelen == 1)
                                goto next;

                        if (ent->lde_namelen == 2 && ent->lde_name[1] == '.')
                                goto next;
                }

                len = snprintf(name, FID_LEN + 1, DFID":", PFID(&ent->lde_fid));
                /* The ent->lde_name is composed of ${FID}:${index} */
                if (ent->lde_namelen < len + 1 ||
                    memcmp(ent->lde_name, name, len) != 0) {
                        CDEBUG(lod->lod_lmv_failout ? D_ERROR : D_INFO,
                               "%s: invalid shard name %.*s with the FID "DFID
                               " for the striped directory "DFID", %s\n",
                               lod2obd(lod)->obd_name, ent->lde_namelen,
                               ent->lde_name, PFID(&fid),
                               PFID(lu_object_fid(&obj->do_lu)),
                               lod->lod_lmv_failout ? "failout" : "skip");

                        if (lod->lod_lmv_failout)
                                break;

                        goto next;
                }

                index = 0;
                do {
                        if (ent->lde_name[len] < '0' ||
                            ent->lde_name[len] > '9') {
                                CDEBUG(lod->lod_lmv_failout ? D_ERROR : D_INFO,
                                       "%s: invalid shard name %.*s with the "
                                       "FID "DFID" for the striped directory "
                                       DFID", %s\n",
                                       lod2obd(lod)->obd_name, ent->lde_namelen,
                                       ent->lde_name, PFID(&fid),
                                       PFID(lu_object_fid(&obj->do_lu)),
                                       lod->lod_lmv_failout ?
                                       "failout" : "skip");

                                if (lod->lod_lmv_failout)
                                        break;

                                goto next;
                        }

                        index = index * 10 + ent->lde_name[len++] - '0';
                } while (len < ent->lde_namelen);

                if (len == ent->lde_namelen) {
                        /* Out of LMV EA range. */
                        if (index >= stripes) {
                                CERROR("%s: the shard %.*s for the striped "
                                       "directory "DFID" is out of the known "
                                       "LMV EA range [0 - %u], failout\n",
                                       lod2obd(lod)->obd_name, ent->lde_namelen,
                                       ent->lde_name,
                                       PFID(lu_object_fid(&obj->do_lu)),
                                       stripes - 1);

                                break;
                        }

                        /* The slot has been occupied. */
                        if (!fid_is_zero(&lmv1->lmv_stripe_fids[index])) {
                                struct lu_fid fid0;

                                fid_le_to_cpu(&fid0,
                                        &lmv1->lmv_stripe_fids[index]);
                                CERROR("%s: both the shard "DFID" and "DFID
                                       " for the striped directory "DFID
                                       " claim the same LMV EA slot at the "
                                       "index %d, failout\n",
                                       lod2obd(lod)->obd_name,
                                       PFID(&fid0), PFID(&fid),
                                       PFID(lu_object_fid(&obj->do_lu)), index);

                                break;
                        }

                        /* stored as LE mode */
                        lmv1->lmv_stripe_fids[index] = ent->lde_fid;

next:
                        rc = iops->next(env, it);
                }
        }

        iops->put(env, it);
        iops->fini(env, it);

        RETURN(rc > 0 ? lmv_mds_md_size(stripes, magic) : rc);
}

/**
 * Implementation of dt_object_operations::do_index_try.
 *
 * \see dt_object_operations::do_index_try() in the API description for details.
 */
static int lod_index_try(const struct lu_env *env, struct dt_object *dt,
                         const struct dt_index_features *feat)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct dt_object        *next = dt_object_child(dt);
        int                     rc;
        ENTRY;

        LASSERT(next->do_ops);
        LASSERT(next->do_ops->do_index_try);

        rc = lod_load_striping_locked(env, lo);
        if (rc != 0)
                RETURN(rc);

        rc = next->do_ops->do_index_try(env, next, feat);
        if (rc != 0)
                RETURN(rc);

        if (lo->ldo_stripenr > 0) {
                int i;

                for (i = 0; i < lo->ldo_stripenr; i++) {
                        if (dt_object_exists(lo->ldo_stripe[i]) == 0)
                                continue;
                        rc = lo->ldo_stripe[i]->do_ops->do_index_try(env,
                                                lo->ldo_stripe[i], feat);
                        if (rc != 0)
                                RETURN(rc);
                }
                dt->do_index_ops = &lod_striped_index_ops;
        } else {
                dt->do_index_ops = &lod_index_ops;
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_read_lock.
 *
 * \see dt_object_operations::do_read_lock() in the API description for details.
 */
static void lod_object_read_lock(const struct lu_env *env,
                                 struct dt_object *dt, unsigned role)
{
        dt_read_lock(env, dt_object_child(dt), role);
}

/**
 * Implementation of dt_object_operations::do_write_lock.
 *
 * \see dt_object_operations::do_write_lock() in the API description for
 * details.
 */
static void lod_object_write_lock(const struct lu_env *env,
                                  struct dt_object *dt, unsigned role)
{
        dt_write_lock(env, dt_object_child(dt), role);
}

/**
 * Implementation of dt_object_operations::do_read_unlock.
 *
 * \see dt_object_operations::do_read_unlock() in the API description for
 * details.
 */
static void lod_object_read_unlock(const struct lu_env *env,
                                   struct dt_object *dt)
{
        dt_read_unlock(env, dt_object_child(dt));
}

/**
 * Implementation of dt_object_operations::do_write_unlock.
 *
 * \see dt_object_operations::do_write_unlock() in the API description for
 * details.
 */
static void lod_object_write_unlock(const struct lu_env *env,
                                    struct dt_object *dt)
{
        dt_write_unlock(env, dt_object_child(dt));
}

/**
 * Implementation of dt_object_operations::do_write_locked.
 *
 * \see dt_object_operations::do_write_locked() in the API description for
 * details.
 */
static int lod_object_write_locked(const struct lu_env *env,
                                   struct dt_object *dt)
{
        return dt_write_locked(env, dt_object_child(dt));
}

/**
 * Implementation of dt_object_operations::do_attr_get.
 *
 * \see dt_object_operations::do_attr_get() in the API description for details.
 */
static int lod_attr_get(const struct lu_env *env,
                        struct dt_object *dt,
                        struct lu_attr *attr,
                        struct lustre_capa *capa)
{
        /* Note: for striped directory, client will merge attributes
         * from all of the sub-stripes see lmv_merge_attr(), and there
         * no MDD logic depend on directory nlink/size/time, so we can
         * always use master inode nlink and size for now. */
        return dt_attr_get(env, dt_object_child(dt), attr, capa);
}

/**
 * Mark all of the striped directory sub-stripes dead.
 *
 * When a striped object is a subject to removal, we have
 * to mark all the stripes to prevent further access to
 * them (e.g. create a new file in those). So we mark
 * all the stripes with LMV_HASH_FLAG_DEAD. The function
 * can be used to declare the changes and to apply them.
 * If the object isn't striped, then just return success.
 *
 * \param[in] env       execution environment
 * \param[in] dt        the striped object
 * \param[in] handle    transaction handle
 * \param[in] declare   whether to declare the change or apply
 *
 * \retval              0 on success
 * \retval              negative if failed
 **/
static int lod_mark_dead_object(const struct lu_env *env,
                                struct dt_object *dt,
                                struct thandle *handle,
                                bool declare)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lmv_mds_md_v1    *lmv;
        __u32                   dead_hash_type;
        int                     rc;
        int                     i;

        ENTRY;

        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr))
                RETURN(0);

        rc = lod_load_striping_locked(env, lo);
        if (rc != 0)
                RETURN(rc);

        if (lo->ldo_stripenr == 0)
                RETURN(0);

        rc = lod_get_lmv_ea(env, lo);
        if (rc <= 0)
                RETURN(rc);

        lmv = lod_env_info(env)->lti_ea_store;
        lmv->lmv_magic = cpu_to_le32(LMV_MAGIC_STRIPE);
        dead_hash_type = le32_to_cpu(lmv->lmv_hash_type) | LMV_HASH_FLAG_DEAD;
        lmv->lmv_hash_type = cpu_to_le32(dead_hash_type);
        for (i = 0; i < lo->ldo_stripenr; i++) {
                struct lu_buf buf;

                lmv->lmv_master_mdt_index = i;
                buf.lb_buf = lmv;
                buf.lb_len = sizeof(*lmv);
                if (declare) {
                        rc = dt_declare_xattr_set(env, lo->ldo_stripe[i], &buf,
                                                  XATTR_NAME_LMV,
                                                  LU_XATTR_REPLACE, handle);
                } else {
                        rc = dt_xattr_set(env, lo->ldo_stripe[i], &buf,
                                          XATTR_NAME_LMV, LU_XATTR_REPLACE,
                                          handle, BYPASS_CAPA);
                }
                if (rc != 0)
                        break;
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_declare_attr_set.
 *
 * If the object is striped, then apply the changes to all the stripes.
 *
 * \see dt_object_operations::do_declare_attr_set() in the API description
 * for details.
 */
static int lod_declare_attr_set(const struct lu_env *env,
                                struct dt_object *dt,
                                const struct lu_attr *attr,
                                struct thandle *handle)
{
        struct dt_object  *next = dt_object_child(dt);
        struct lod_object *lo = lod_dt_obj(dt);
        int                rc, i;
        ENTRY;

        /* Set dead object on all other stripes */
        if (attr->la_valid & LA_FLAGS && !(attr->la_valid & ~LA_FLAGS) &&
            attr->la_flags & LUSTRE_SLAVE_DEAD_FL) {
                rc = lod_mark_dead_object(env, dt, handle, true);
                RETURN(rc);
        }

        /*
         * declare setattr on the local object
         */
        rc = dt_declare_attr_set(env, next, attr, handle);
        if (rc)
                RETURN(rc);

        /* osp_declare_attr_set() ignores all attributes other than
         * UID, GID, and size, and osp_attr_set() ignores all but UID
         * and GID.  Declaration of size attr setting happens through
         * lod_declare_init_size(), and not through this function.
         * Therefore we need not load striping unless ownership is
         * changing.  This should save memory and (we hope) speed up
         * rename(). */
        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr)) {
                if (!(attr->la_valid & (LA_UID | LA_GID)))
                        RETURN(rc);

                if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_OWNER))
                        RETURN(0);
        } else {
                if (!(attr->la_valid & (LA_UID | LA_GID | LA_MODE |
                                        LA_ATIME | LA_MTIME | LA_CTIME)))
                        RETURN(rc);
        }
        /*
         * load striping information, notice we don't do this when object
         * is being initialized as we don't need this information till
         * few specific cases like destroy, chown
         */
        rc = lod_load_striping(env, lo);
        if (rc)
                RETURN(rc);

        if (lo->ldo_stripenr == 0)
                RETURN(0);

        /*
         * if object is striped declare changes on the stripes
         */
        LASSERT(lo->ldo_stripe);
        for (i = 0; i < lo->ldo_stripenr; i++) {
                if (likely(lo->ldo_stripe[i] != NULL)) {
                        rc = dt_declare_attr_set(env, lo->ldo_stripe[i], attr,
                                                 handle);
                        if (rc != 0) {
                                CERROR("failed declaration: %d\n", rc);
                                break;
                        }
                }
        }

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_LOST_STRIPE) &&
            dt_object_exists(next) != 0 &&
            dt_object_remote(next) == 0)
                dt_declare_xattr_del(env, next, XATTR_NAME_LOV, handle);

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_CHANGE_STRIPE) &&
            dt_object_exists(next) &&
            dt_object_remote(next) == 0 && S_ISREG(attr->la_mode)) {
                struct lod_thread_info *info = lod_env_info(env);
                struct lu_buf *buf = &info->lti_buf;

                buf->lb_buf = info->lti_ea_store;
                buf->lb_len = info->lti_ea_store_size;
                dt_declare_xattr_set(env, next, buf, XATTR_NAME_LOV,
                                     LU_XATTR_REPLACE, handle);
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_attr_set.
 *
 * If the object is striped, then apply the changes to all or subset of
 * the stripes depending on the object type and specific attributes.
 *
 * \see dt_object_operations::do_attr_set() in the API description for details.
 */
static int lod_attr_set(const struct lu_env *env,
                        struct dt_object *dt,
                        const struct lu_attr *attr,
                        struct thandle *handle,
                        struct lustre_capa *capa)
{
        struct dt_object        *next = dt_object_child(dt);
        struct lod_object       *lo = lod_dt_obj(dt);
        int                     rc, i;
        ENTRY;

        /* Set dead object on all other stripes */
        if (attr->la_valid & LA_FLAGS && !(attr->la_valid & ~LA_FLAGS) &&
            attr->la_flags & LUSTRE_SLAVE_DEAD_FL) {
                rc = lod_mark_dead_object(env, dt, handle, false);
                RETURN(rc);
        }

        /*
         * apply changes to the local object
         */
        rc = dt_attr_set(env, next, attr, handle, capa);
        if (rc)
                RETURN(rc);

        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr)) {
                if (!(attr->la_valid & (LA_UID | LA_GID)))
                        RETURN(rc);

                if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_OWNER))
                        RETURN(0);
        } else {
                if (!(attr->la_valid & (LA_UID | LA_GID | LA_MODE |
                                        LA_ATIME | LA_MTIME | LA_CTIME)))
                        RETURN(rc);
        }

        if (lo->ldo_stripenr == 0)
                RETURN(0);

        /*
         * if object is striped, apply changes to all the stripes
         */
        LASSERT(lo->ldo_stripe);
        for (i = 0; i < lo->ldo_stripenr; i++) {
                if (unlikely(lo->ldo_stripe[i] == NULL))
                        continue;
                if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
                    (dt_object_exists(lo->ldo_stripe[i]) == 0))
                        continue;

                rc = dt_attr_set(env, lo->ldo_stripe[i], attr, handle, capa);
                if (rc != 0) {
                        CERROR("failed declaration: %d\n", rc);
                        break;
                }
        }

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_LOST_STRIPE) &&
            dt_object_exists(next) != 0 &&
            dt_object_remote(next) == 0)
                dt_xattr_del(env, next, XATTR_NAME_LOV, handle, BYPASS_CAPA);

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_CHANGE_STRIPE) &&
            dt_object_exists(next) &&
            dt_object_remote(next) == 0 && S_ISREG(attr->la_mode)) {
                struct lod_thread_info *info = lod_env_info(env);
                struct lu_buf *buf = &info->lti_buf;
                struct ost_id *oi = &info->lti_ostid;
                struct lu_fid *fid = &info->lti_fid;
                struct lov_mds_md_v1 *lmm;
                struct lov_ost_data_v1 *objs;
                __u32 magic;
                int rc1;

                rc1 = lod_get_lov_ea(env, lo);
                if (rc1  <= 0)
                        RETURN(rc);

                buf->lb_buf = info->lti_ea_store;
                buf->lb_len = info->lti_ea_store_size;
                lmm = info->lti_ea_store;
                magic = le32_to_cpu(lmm->lmm_magic);
                if (magic == LOV_MAGIC_V1)
                        objs = &(lmm->lmm_objects[0]);
                else
                        objs = &((struct lov_mds_md_v3 *)lmm)->lmm_objects[0];
                ostid_le_to_cpu(&objs->l_ost_oi, oi);
                ostid_to_fid(fid, oi, le32_to_cpu(objs->l_ost_idx));
                fid->f_oid--;
                fid_to_ostid(fid, oi);
                ostid_cpu_to_le(oi, &objs->l_ost_oi);
                dt_xattr_set(env, next, buf, XATTR_NAME_LOV,
                             LU_XATTR_REPLACE, handle, BYPASS_CAPA);
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_xattr_get.
 *
 * If LOV EA is requested from the root object and it's not
 * found, then return default striping for the filesystem.
 *
 * \see dt_object_operations::do_xattr_get() in the API description for details.
 */
static int lod_xattr_get(const struct lu_env *env, struct dt_object *dt,
                         struct lu_buf *buf, const char *name,
                         struct lustre_capa *capa)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lod_device       *dev = lu2lod_dev(dt->do_lu.lo_dev);
        int                      rc, is_root;
        ENTRY;

        rc = dt_xattr_get(env, dt_object_child(dt), buf, name, capa);
        if (strcmp(name, XATTR_NAME_LMV) == 0) {
                struct lmv_mds_md_v1    *lmv1;
                int                      rc1 = 0;

                if (rc > (typeof(rc))sizeof(*lmv1))
                        RETURN(rc);

                if (rc < (typeof(rc))sizeof(*lmv1))
                        RETURN(rc = rc > 0 ? -EINVAL : rc);

                if (buf->lb_buf == NULL || buf->lb_len == 0) {
                        CLASSERT(sizeof(*lmv1) <= sizeof(info->lti_key));

                        info->lti_buf.lb_buf = info->lti_key;
                        info->lti_buf.lb_len = sizeof(*lmv1);
                        rc = dt_xattr_get(env, dt_object_child(dt),
                                          &info->lti_buf, name, capa);
                        if (unlikely(rc != sizeof(*lmv1)))
                                RETURN(rc = rc > 0 ? -EINVAL : rc);

                        lmv1 = info->lti_buf.lb_buf;
                        /* The on-disk LMV EA only contains header, but the
                         * returned LMV EA size should contain the space for
                         * the FIDs of all shards of the striped directory. */
                        if (le32_to_cpu(lmv1->lmv_magic) == LMV_MAGIC_V1)
                                rc = lmv_mds_md_size(
                                        le32_to_cpu(lmv1->lmv_stripe_count),
                                        LMV_MAGIC_V1);
                } else {
                        rc1 = lod_load_lmv_shards(env, lod_dt_obj(dt),
                                                  buf, false);
                }

                RETURN(rc = rc1 != 0 ? rc1 : rc);
        }

        if (rc != -ENODATA || !S_ISDIR(dt->do_lu.lo_header->loh_attr & S_IFMT))
                RETURN(rc);

        /*
         * lod returns default striping on the real root of the device
         * this is like the root stores default striping for the whole
         * filesystem. historically we've been using a different approach
         * and store it in the config.
         */
        dt_root_get(env, dev->lod_child, &info->lti_fid);
        is_root = lu_fid_eq(&info->lti_fid, lu_object_fid(&dt->do_lu));

        if (is_root && strcmp(XATTR_NAME_LOV, name) == 0) {
                struct lov_user_md *lum = buf->lb_buf;
                struct lov_desc    *desc = &dev->lod_desc;

                if (buf->lb_buf == NULL) {
                        rc = sizeof(*lum);
                } else if (buf->lb_len >= sizeof(*lum)) {
                        lum->lmm_magic = cpu_to_le32(LOV_USER_MAGIC_V1);
                        lmm_oi_set_seq(&lum->lmm_oi, FID_SEQ_LOV_DEFAULT);
                        lmm_oi_set_id(&lum->lmm_oi, 0);
                        lmm_oi_cpu_to_le(&lum->lmm_oi, &lum->lmm_oi);
                        lum->lmm_pattern = cpu_to_le32(desc->ld_pattern);
                        lum->lmm_stripe_size = cpu_to_le32(
                                                desc->ld_default_stripe_size);
                        lum->lmm_stripe_count = cpu_to_le16(
                                                desc->ld_default_stripe_count);
                        lum->lmm_stripe_offset = cpu_to_le16(
                                                desc->ld_default_stripe_offset);
                        rc = sizeof(*lum);
                } else {
                        rc = -ERANGE;
                }
        }

        RETURN(rc);
}

/**
 * Verify LVM EA.
 *
 * Checks that the magic and the number of the stripes are sane.
 *
 * \param[in] lod       lod device
 * \param[in] lum       a buffer storing LMV EA to verify
 *
 * \retval              0 if the EA is sane
 * \retval              negative otherwise
 */
static int lod_verify_md_striping(struct lod_device *lod,
                                  const struct lmv_user_md_v1 *lum)
{
        int     rc = 0;
        ENTRY;

        if (unlikely(le32_to_cpu(lum->lum_magic) != LMV_USER_MAGIC))
                GOTO(out, rc = -EINVAL);

        if (unlikely(le32_to_cpu(lum->lum_stripe_count) == 0))
                GOTO(out, rc = -EINVAL);
out:
        if (rc != 0)
                CERROR("%s: invalid lmv_user_md: magic = %x, "
                       "stripe_offset = %d, stripe_count = %u: rc = %d\n",
                       lod2obd(lod)->obd_name, le32_to_cpu(lum->lum_magic),
                       (int)le32_to_cpu(lum->lum_stripe_offset),
                       le32_to_cpu(lum->lum_stripe_count), rc);
        return rc;
}

/**
 * Initialize LMV EA for a slave.
 *
 * Initialize slave's LMV EA from the master's LMV EA.
 *
 * \param[in] master_lmv        a buffer containing master's EA
 * \param[out] slave_lmv        a buffer where slave's EA will be stored
 *
 */
static void lod_prep_slave_lmv_md(struct lmv_mds_md_v1 *slave_lmv,
                                  const struct lmv_mds_md_v1 *master_lmv)
{
        *slave_lmv = *master_lmv;
        slave_lmv->lmv_magic = cpu_to_le32(LMV_MAGIC_STRIPE);
}

/**
 * Generate LMV EA.
 *
 * Generate LMV EA from the object passed as \a dt. The object must have
 * the stripes created and initialized.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[out] lmv_buf  buffer storing generated LMV EA
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
int lod_prep_lmv_md(const struct lu_env *env, struct dt_object *dt,
                    struct lu_buf *lmv_buf)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lod_device       *lod = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lmv_mds_md_v1    *lmm1;
        int                     stripe_count;
        int                     type = LU_SEQ_RANGE_ANY;
        int                     rc;
        __u32                   mdtidx;
        ENTRY;

        LASSERT(lo->ldo_dir_striped != 0);
        LASSERT(lo->ldo_stripenr > 0);
        stripe_count = lo->ldo_stripenr;
        /* Only store the LMV EA heahder on the disk. */
        if (info->lti_ea_store_size < sizeof(*lmm1)) {
                rc = lod_ea_store_resize(info, sizeof(*lmm1));
                if (rc != 0)
                        RETURN(rc);
        } else {
                memset(info->lti_ea_store, 0, sizeof(*lmm1));
        }

        lmm1 = (struct lmv_mds_md_v1 *)info->lti_ea_store;
        lmm1->lmv_magic = cpu_to_le32(LMV_MAGIC);
        lmm1->lmv_stripe_count = cpu_to_le32(stripe_count);
        lmm1->lmv_hash_type = cpu_to_le32(lo->ldo_dir_hash_type);
        rc = lod_fld_lookup(env, lod, lu_object_fid(&dt->do_lu),
                            &mdtidx, &type);
        if (rc != 0)
                RETURN(rc);

        lmm1->lmv_master_mdt_index = cpu_to_le32(mdtidx);
        lmv_buf->lb_buf = info->lti_ea_store;
        lmv_buf->lb_len = sizeof(*lmm1);
        lo->ldo_dir_striping_cached = 1;

        RETURN(rc);
}

/**
 * Create in-core represenation for a striped directory.
 *
 * Parse the buffer containing LMV EA and instantiate LU objects
 * representing the stripe objects. The pointers to the objects are
 * stored in ldo_stripe field of \a lo. This function is used when
 * we need to access an already created object (i.e. load from a disk).
 *
 * \param[in] env       execution environment
 * \param[in] lo        lod object
 * \param[in] buf       buffer containing LMV EA
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
int lod_parse_dir_striping(const struct lu_env *env, struct lod_object *lo,
                           const struct lu_buf *buf)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lod_device       *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct lod_tgt_descs    *ltd = &lod->lod_mdt_descs;
        struct dt_object        **stripe;
        union lmv_mds_md        *lmm = buf->lb_buf;
        struct lmv_mds_md_v1    *lmv1 = &lmm->lmv_md_v1;
        struct lu_fid           *fid = &info->lti_fid;
        unsigned int            i;
        int                     rc = 0;
        ENTRY;

        if (le32_to_cpu(lmv1->lmv_hash_type) & LMV_HASH_FLAG_MIGRATION)
                RETURN(0);

        if (le32_to_cpu(lmv1->lmv_magic) == LMV_MAGIC_STRIPE) {
                lo->ldo_dir_slave_stripe = 1;
                RETURN(0);
        }

        if (le32_to_cpu(lmv1->lmv_magic) != LMV_MAGIC_V1)
                RETURN(-EINVAL);

        if (le32_to_cpu(lmv1->lmv_stripe_count) < 1)
                RETURN(0);

        LASSERT(lo->ldo_stripe == NULL);
        OBD_ALLOC(stripe, sizeof(stripe[0]) *
                  (le32_to_cpu(lmv1->lmv_stripe_count)));
        if (stripe == NULL)
                RETURN(-ENOMEM);

        for (i = 0; i < le32_to_cpu(lmv1->lmv_stripe_count); i++) {
                struct dt_device        *tgt_dt;
                struct dt_object        *dto;
                int                     type = LU_SEQ_RANGE_ANY;
                __u32                   idx;

                fid_le_to_cpu(fid, &lmv1->lmv_stripe_fids[i]);
                if (!fid_is_sane(fid))
                        GOTO(out, rc = -ESTALE);

                rc = lod_fld_lookup(env, lod, fid, &idx, &type);
                if (rc != 0)
                        GOTO(out, rc);

                if (idx == lod2lu_dev(lod)->ld_site->ld_seq_site->ss_node_id) {
                        tgt_dt = lod->lod_child;
                } else {
                        struct lod_tgt_desc     *tgt;

                        tgt = LTD_TGT(ltd, idx);
                        if (tgt == NULL)
                                GOTO(out, rc = -ESTALE);
                        tgt_dt = tgt->ltd_tgt;
                }

                dto = dt_locate_at(env, tgt_dt, fid,
                                  lo->ldo_obj.do_lu.lo_dev->ld_site->ls_top_dev,
                                  NULL);
                if (IS_ERR(dto))
                        GOTO(out, rc = PTR_ERR(dto));

                stripe[i] = dto;
        }
out:
        lo->ldo_stripe = stripe;
        lo->ldo_stripenr = le32_to_cpu(lmv1->lmv_stripe_count);
        lo->ldo_stripes_allocated = le32_to_cpu(lmv1->lmv_stripe_count);
        if (rc != 0)
                lod_object_free_striping(env, lo);

        RETURN(rc);
}

/**
 * Create a striped directory.
 *
 * Create a striped directory with a given stripe pattern on the specified MDTs.
 * A striped directory is represented as a regular directory - an index listing
 * all the stripes. The stripes point back to the master object with ".." and
 * LinkEA. The master object gets LMV EA which identifies it as a striped
 * directory. The function allocates FIDs for all the stripes.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] attr      attributes to initialize the objects with
 * \param[in] lum       a pattern specifying the number of stripes and
 *                      MDT to start from
 * \param[in] dof       type of objects to be created
 * \param[in] th        transaction handle
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_prep_md_striped_create(const struct lu_env *env,
                                      struct dt_object *dt,
                                      struct lu_attr *attr,
                                      const struct lmv_user_md_v1 *lum,
                                      struct dt_object_format *dof,
                                      struct thandle *th)
{
        struct lod_device       *lod = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_tgt_descs    *ltd = &lod->lod_mdt_descs;
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lod_thread_info  *info = lod_env_info(env);
        struct dt_object        **stripe;
        struct lu_buf           lmv_buf;
        struct lu_buf           slave_lmv_buf;
        struct lmv_mds_md_v1    *lmm;
        struct lmv_mds_md_v1    *slave_lmm = NULL;
        struct dt_insert_rec    *rec = &info->lti_dt_rec;
        __u32                   stripe_count;
        int                     *idx_array;
        int                     rc = 0;
        __u32                   i;
        __u32                   j;
        ENTRY;

        /* The lum has been verifed in lod_verify_md_striping */
        LASSERT(le32_to_cpu(lum->lum_magic) == LMV_USER_MAGIC);
        LASSERT(le32_to_cpu(lum->lum_stripe_count) > 0);

        stripe_count = le32_to_cpu(lum->lum_stripe_count);

        /* shrink the stripe_count to the avaible MDT count */
        if (stripe_count > lod->lod_remote_mdt_count + 1)
                stripe_count = lod->lod_remote_mdt_count + 1;

        OBD_ALLOC(stripe, sizeof(stripe[0]) * stripe_count);
        if (stripe == NULL)
                RETURN(-ENOMEM);

        OBD_ALLOC(idx_array, sizeof(idx_array[0]) * stripe_count);
        if (idx_array == NULL)
                GOTO(out_free, rc = -ENOMEM);

        for (i = 0; i < stripe_count; i++) {
                struct lod_tgt_desc     *tgt = NULL;
                struct dt_object        *dto;
                struct lu_fid           fid = { 0 };
                int                     idx;
                struct lu_object_conf   conf = { 0 };
                struct dt_device        *tgt_dt = NULL;

                if (i == 0) {
                        /* Right now, master stripe and master object are
                         * on the same MDT */
                        idx = le32_to_cpu(lum->lum_stripe_offset);
                        rc = obd_fid_alloc(env, lod->lod_child_exp, &fid,
                                           NULL);
                        if (rc < 0)
                                GOTO(out_put, rc);
                        tgt_dt = lod->lod_child;
                        goto next;
                }

                idx = (idx_array[i - 1] + 1) % (lod->lod_remote_mdt_count + 1);

                for (j = 0; j < lod->lod_remote_mdt_count;
                     j++, idx = (idx + 1) % (lod->lod_remote_mdt_count + 1)) {
                        bool already_allocated = false;
                        __u32 k;

                        CDEBUG(D_INFO, "try idx %d, mdt cnt %u,"
                               " allocated %u, last allocated %d\n", idx,
                               lod->lod_remote_mdt_count, i, idx_array[i - 1]);

                        /* Find next available target */
                        if (!cfs_bitmap_check(ltd->ltd_tgt_bitmap, idx))
                                continue;

                        /* check whether the idx already exists
                         * in current allocated array */
                        for (k = 0; k < i; k++) {
                                if (idx_array[k] == idx) {
                                        already_allocated = true;
                                        break;
                                }
                        }

                        if (already_allocated)
                                continue;

                        /* check the status of the OSP */
                        tgt = LTD_TGT(ltd, idx);
                        if (tgt == NULL)
                                continue;

                        tgt_dt = tgt->ltd_tgt;
                        rc = dt_statfs(env, tgt_dt, NULL);
                        if (rc) {
                                /* this OSP doesn't feel well */
                                rc = 0;
                                continue;
                        }

                        rc = obd_fid_alloc(env, tgt->ltd_exp, &fid, NULL);
                        if (rc < 0) {
                                rc = 0;
                                continue;
                        }

                        break;
                }

                /* Can not allocate more stripes */
                if (j == lod->lod_remote_mdt_count) {
                        CDEBUG(D_INFO, "%s: require stripes %u only get %d\n",
                               lod2obd(lod)->obd_name, stripe_count, i - 1);
                        break;
                }

                CDEBUG(D_INFO, "idx %d, mdt cnt %u,"
                       " allocated %u, last allocated %d\n", idx,
                       lod->lod_remote_mdt_count, i, idx_array[i - 1]);

next:
                /* tgt_dt and fid must be ready after search avaible OSP
                 * in the above loop */
                LASSERT(tgt_dt != NULL);
                LASSERT(fid_is_sane(&fid));
                conf.loc_flags = LOC_F_NEW;
                dto = dt_locate_at(env, tgt_dt, &fid,
                                   dt->do_lu.lo_dev->ld_site->ls_top_dev,
                                   &conf);
                if (IS_ERR(dto))
                        GOTO(out_put, rc = PTR_ERR(dto));
                stripe[i] = dto;
                idx_array[i] = idx;
        }

        lo->ldo_dir_striped = 1;
        lo->ldo_stripe = stripe;
        lo->ldo_stripenr = i;
        lo->ldo_stripes_allocated = stripe_count;

        if (lo->ldo_stripenr == 0)
                GOTO(out_put, rc = -ENOSPC);

        rc = lod_prep_lmv_md(env, dt, &lmv_buf);
        if (rc != 0)
                GOTO(out_put, rc);
        lmm = lmv_buf.lb_buf;

        OBD_ALLOC_PTR(slave_lmm);
        if (slave_lmm == NULL)
                GOTO(out_put, rc = -ENOMEM);

        lod_prep_slave_lmv_md(slave_lmm, lmm);
        slave_lmv_buf.lb_buf = slave_lmm;
        slave_lmv_buf.lb_len = sizeof(*slave_lmm);

        if (!dt_try_as_dir(env, dt_object_child(dt)))
                GOTO(out_put, rc = -EINVAL);

        rec->rec_type = S_IFDIR;
        for (i = 0; i < lo->ldo_stripenr; i++) {
                struct dt_object        *dto            = stripe[i];
                char                    *stripe_name    = info->lti_key;
                struct lu_name          *sname;
                struct linkea_data       ldata          = { 0 };
                struct lu_buf            linkea_buf;

                rc = dt_declare_create(env, dto, attr, NULL, dof, th);
                if (rc != 0)
                        GOTO(out_put, rc);

                if (!dt_try_as_dir(env, dto))
                        GOTO(out_put, rc = -EINVAL);

                rec->rec_fid = lu_object_fid(&dto->do_lu);
                rc = dt_declare_insert(env, dto, (const struct dt_rec *)rec,
                                       (const struct dt_key *)dot, th);
                if (rc != 0)
                        GOTO(out_put, rc);

                /* master stripe FID will be put to .. */
                rec->rec_fid = lu_object_fid(&dt->do_lu);
                rc = dt_declare_insert(env, dto, (const struct dt_rec *)rec,
                                       (const struct dt_key *)dotdot, th);
                if (rc != 0)
                        GOTO(out_put, rc);

                /* probably nothing to inherite */
                if (lo->ldo_striping_cached &&
                    !LOVEA_DELETE_VALUES(lo->ldo_def_stripe_size,
                                         lo->ldo_def_stripenr,
                                         lo->ldo_def_stripe_offset)) {
                        struct lov_user_md_v3   *v3;

                        /* sigh, lti_ea_store has been used for lmv_buf,
                         * so we have to allocate buffer for default
                         * stripe EA */
                        OBD_ALLOC_PTR(v3);
                        if (v3 == NULL)
                                GOTO(out_put, rc = -ENOMEM);

                        memset(v3, 0, sizeof(*v3));
                        v3->lmm_magic = cpu_to_le32(LOV_USER_MAGIC_V3);
                        v3->lmm_stripe_count =
                                cpu_to_le16(lo->ldo_def_stripenr);
                        v3->lmm_stripe_offset =
                                cpu_to_le16(lo->ldo_def_stripe_offset);
                        v3->lmm_stripe_size =
                                cpu_to_le32(lo->ldo_def_stripe_size);
                        if (lo->ldo_pool != NULL)
                                strlcpy(v3->lmm_pool_name, lo->ldo_pool,
                                        sizeof(v3->lmm_pool_name));

                        info->lti_buf.lb_buf = v3;
                        info->lti_buf.lb_len = sizeof(*v3);
                        rc = dt_declare_xattr_set(env, dto,
                                                  &info->lti_buf,
                                                  XATTR_NAME_LOV,
                                                  0, th);
                        OBD_FREE_PTR(v3);
                        if (rc != 0)
                                GOTO(out_put, rc);
                }

                slave_lmm->lmv_master_mdt_index = cpu_to_le32(i);
                rc = dt_declare_xattr_set(env, dto, &slave_lmv_buf,
                                          XATTR_NAME_LMV, 0, th);
                if (rc != 0)
                        GOTO(out_put, rc);

                snprintf(stripe_name, sizeof(info->lti_key), DFID":%u",
                        PFID(lu_object_fid(&dto->do_lu)), i);

                sname = lod_name_get(env, stripe_name, strlen(stripe_name));
                rc = linkea_data_new(&ldata, &info->lti_linkea_buf);
                if (rc != 0)
                        GOTO(out_put, rc);

                rc = linkea_add_buf(&ldata, sname, lu_object_fid(&dt->do_lu));
                if (rc != 0)
                        GOTO(out_put, rc);

                linkea_buf.lb_buf = ldata.ld_buf->lb_buf;
                linkea_buf.lb_len = ldata.ld_leh->leh_len;
                rc = dt_declare_xattr_set(env, dto, &linkea_buf,
                                          XATTR_NAME_LINK, 0, th);
                if (rc != 0)
                        GOTO(out_put, rc);

                rec->rec_fid = lu_object_fid(&dto->do_lu);
                rc = dt_declare_insert(env, dt_object_child(dt),
                                       (const struct dt_rec *)rec,
                                       (const struct dt_key *)stripe_name, th);
                if (rc != 0)
                        GOTO(out_put, rc);

                rc = dt_declare_ref_add(env, dt_object_child(dt), th);
                if (rc != 0)
                        GOTO(out_put, rc);
        }

        rc = dt_declare_xattr_set(env, dt_object_child(dt), &lmv_buf,
                                  XATTR_NAME_LMV, 0, th);
        if (rc != 0)
                GOTO(out_put, rc);

out_put:
        if (rc < 0) {
                for (i = 0; i < stripe_count; i++)
                        if (stripe[i] != NULL)
                                lu_object_put(env, &stripe[i]->do_lu);
                OBD_FREE(stripe, sizeof(stripe[0]) * stripe_count);
                lo->ldo_stripenr = 0;
                lo->ldo_stripes_allocated = 0;
                lo->ldo_stripe = NULL;
        }

out_free:
        if (idx_array != NULL)
                OBD_FREE(idx_array, sizeof(idx_array[0]) * stripe_count);
        if (slave_lmm != NULL)
                OBD_FREE_PTR(slave_lmm);

        RETURN(rc);
}

/**
 * Declare create striped md object.
 *
 * The function declares intention to create a striped directory. This is a
 * wrapper for lod_prep_md_striped_create(). The only additional functionality
 * is to verify pattern \a lum_buf is good. Check that function for the details.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] attr      attributes to initialize the objects with
 * \param[in] lum_buf   a pattern specifying the number of stripes and
 *                      MDT to start from
 * \param[in] dof       type of objects to be created
 * \param[in] th        transaction handle
 *
 * \retval              0 on success
 * \retval              negative if failed
 *
 */
static int lod_declare_xattr_set_lmv(const struct lu_env *env,
                                     struct dt_object *dt,
                                     struct lu_attr *attr,
                                     const struct lu_buf *lum_buf,
                                     struct dt_object_format *dof,
                                     struct thandle *th)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lod_device       *lod = lu2lod_dev(dt->do_lu.lo_dev);
        struct lmv_user_md_v1   *lum;
        int                     rc;
        ENTRY;

        lum = lum_buf->lb_buf;
        LASSERT(lum != NULL);

        CDEBUG(D_INFO, "lum magic = %x count = %u offset = %d\n",
               le32_to_cpu(lum->lum_magic), le32_to_cpu(lum->lum_stripe_count),
               (int)le32_to_cpu(lum->lum_stripe_offset));

        if (le32_to_cpu(lum->lum_stripe_count) == 0)
                GOTO(out, rc = 0);

        rc = lod_verify_md_striping(lod, lum);
        if (rc != 0)
                GOTO(out, rc);

        /* prepare dir striped objects */
        rc = lod_prep_md_striped_create(env, dt, attr, lum, dof, th);
        if (rc != 0) {
                /* failed to create striping, let's reset
                 * config so that others don't get confused */
                lod_object_free_striping(env, lo);
                GOTO(out, rc);
        }
out:
        RETURN(rc);
}


/**
 * Implementation of dt_object_operations::do_declare_xattr_set.
 *
 * Used with regular (non-striped) objects. Basically it
 * initializes the striping information and applies the
 * change to all the stripes.
 *
 * \see dt_object_operations::do_declare_xattr_set() in the API description
 * for details.
 */
static int lod_dir_declare_xattr_set(const struct lu_env *env,
                                     struct dt_object *dt,
                                     const struct lu_buf *buf,
                                     const char *name, int fl,
                                     struct thandle *th)
{
        struct dt_object        *next = dt_object_child(dt);
        struct lod_device       *d = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_object       *lo = lod_dt_obj(dt);
        int                     i;
        int                     rc;
        ENTRY;

        if (strcmp(name, XATTR_NAME_DEFAULT_LMV) == 0) {
                struct lmv_user_md_v1 *lum;

                LASSERT(buf != NULL && buf->lb_buf != NULL);
                lum = buf->lb_buf;
                rc = lod_verify_md_striping(d, lum);
                if (rc != 0)
                        RETURN(rc);
        }

        rc = dt_declare_xattr_set(env, next, buf, name, fl, th);
        if (rc != 0)
                RETURN(rc);

        /* set xattr to each stripes, if needed */
        rc = lod_load_striping(env, lo);
        if (rc != 0)
                RETURN(rc);

        /* Note: Do not set LinkEA on sub-stripes, otherwise
         * it will confuse the fid2path process(see mdt_path_current()).
         * The linkEA between master and sub-stripes is set in
         * lod_xattr_set_lmv(). */
        if (lo->ldo_stripenr == 0 || strcmp(name, XATTR_NAME_LINK) == 0)
                RETURN(0);

        for (i = 0; i < lo->ldo_stripenr; i++) {
                LASSERT(lo->ldo_stripe[i]);
                rc = dt_declare_xattr_set(env, lo->ldo_stripe[i], buf,
                                          name, fl, th);
                if (rc != 0)
                        break;
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_declare_xattr_set.
 *
 * \see dt_object_operations::do_declare_xattr_set() in the API description
 * for details.
 *
 * the extension to the API:
 *   - declaring LOVEA requests striping creation
 *   - LU_XATTR_REPLACE means layout swap
 */
static int lod_declare_xattr_set(const struct lu_env *env,
                                 struct dt_object *dt,
                                 const struct lu_buf *buf,
                                 const char *name, int fl,
                                 struct thandle *th)
{
        struct dt_object *next = dt_object_child(dt);
        struct lu_attr   *attr = &lod_env_info(env)->lti_attr;
        __u32             mode;
        int               rc;
        ENTRY;

        /*
         * allow to declare predefined striping on a new (!mode) object
         * which is supposed to be replay of regular file creation
         * (when LOV setting is declared)
         * LU_XATTR_REPLACE is set to indicate a layout swap
         */
        mode = dt->do_lu.lo_header->loh_attr & S_IFMT;
        if ((S_ISREG(mode) || mode == 0) && strcmp(name, XATTR_NAME_LOV) == 0 &&
             !(fl & LU_XATTR_REPLACE)) {
                /*
                 * this is a request to manipulate object's striping
                 */
                if (dt_object_exists(dt)) {
                        rc = dt_attr_get(env, next, attr, BYPASS_CAPA);
                        if (rc)
                                RETURN(rc);
                } else {
                        memset(attr, 0, sizeof(*attr));
                        attr->la_valid = LA_TYPE | LA_MODE;
                        attr->la_mode = S_IFREG;
                }
                rc = lod_declare_striped_object(env, dt, attr, buf, th);
        } else if (S_ISDIR(mode)) {
                rc = lod_dir_declare_xattr_set(env, dt, buf, name, fl, th);
        } else {
                rc = dt_declare_xattr_set(env, next, buf, name, fl, th);
        }

        RETURN(rc);
}

/**
 * Resets cached default striping in the object.
 *
 * \param[in] lo        object
 */
static void lod_lov_stripe_cache_clear(struct lod_object *lo)
{
        lo->ldo_striping_cached = 0;
        lo->ldo_def_striping_set = 0;
        lod_object_set_pool(lo, NULL);
        lo->ldo_def_stripe_size = 0;
        lo->ldo_def_stripenr = 0;
        if (lo->ldo_dir_stripe != NULL)
                lo->ldo_dir_striping_cached = 0;
}

/**
 * Apply xattr changes to the object.
 *
 * Applies xattr changes to the object and the stripes if the latter exist.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] buf       buffer pointing to the new value of xattr
 * \param[in] name      name of xattr
 * \param[in] fl        flags
 * \param[in] th        transaction handle
 * \param[in] capa      not used currently
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_xattr_set_internal(const struct lu_env *env,
                                  struct dt_object *dt,
                                  const struct lu_buf *buf,
                                  const char *name, int fl, struct thandle *th,
                                  struct lustre_capa *capa)
{
        struct dt_object        *next = dt_object_child(dt);
        struct lod_object       *lo = lod_dt_obj(dt);
        int                     rc;
        int                     i;
        ENTRY;

        rc = dt_xattr_set(env, next, buf, name, fl, th, capa);
        if (rc != 0 || !S_ISDIR(dt->do_lu.lo_header->loh_attr))
                RETURN(rc);

        /* Note: Do not set LinkEA on sub-stripes, otherwise
         * it will confuse the fid2path process(see mdt_path_current()).
         * The linkEA between master and sub-stripes is set in
         * lod_xattr_set_lmv(). */
        if (lo->ldo_stripenr == 0 || strcmp(name, XATTR_NAME_LINK) == 0)
                RETURN(0);

        for (i = 0; i < lo->ldo_stripenr; i++) {
                LASSERT(lo->ldo_stripe[i]);
                rc = dt_xattr_set(env, lo->ldo_stripe[i], buf, name, fl, th,
                                  capa);
                if (rc != 0)
                        break;
        }

        RETURN(rc);
}

/**
 * Delete an extended attribute.
 *
 * Deletes specified xattr from the object and the stripes if the latter exist.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] name      name of xattr
 * \param[in] th        transaction handle
 * \param[in] capa      not used currently
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_xattr_del_internal(const struct lu_env *env,
                                  struct dt_object *dt,
                                  const char *name, struct thandle *th,
                                  struct lustre_capa *capa)
{
        struct dt_object        *next = dt_object_child(dt);
        struct lod_object       *lo = lod_dt_obj(dt);
        int                     rc;
        int                     i;
        ENTRY;

        rc = dt_xattr_del(env, next, name, th, capa);
        if (rc != 0 || !S_ISDIR(dt->do_lu.lo_header->loh_attr))
                RETURN(rc);

        if (lo->ldo_stripenr == 0)
                RETURN(rc);

        for (i = 0; i < lo->ldo_stripenr; i++) {
                LASSERT(lo->ldo_stripe[i]);
                rc = dt_xattr_del(env, lo->ldo_stripe[i], name, th,
                                  capa);
                if (rc != 0)
                        break;
        }

        RETURN(rc);
}

/**
 * Set default striping on a directory.
 *
 * Sets specified striping on a directory object unless it matches the default
 * striping (LOVEA_DELETE_VALUES() macro). In the latter case remove existing
 * EA. This striping will be used when regular file is being created in this
 * directory.
 *
 * \param[in] env       execution environment
 * \param[in] dt        the striped object
 * \param[in] buf       buffer with the striping
 * \param[in] name      name of EA
 * \param[in] fl        xattr flag (see OSD API description)
 * \param[in] th        transaction handle
 * \param[in] capa      not used
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_xattr_set_lov_on_dir(const struct lu_env *env,
                                    struct dt_object *dt,
                                    const struct lu_buf *buf,
                                    const char *name, int fl,
                                    struct thandle *th,
                                    struct lustre_capa *capa)
{
        struct lod_device       *d = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_object       *l = lod_dt_obj(dt);
        struct lov_user_md_v1   *lum;
        struct lov_user_md_v3   *v3 = NULL;
        int                      rc;
        ENTRY;

        /* If it is striped dir, we should clear the stripe cache for
         * slave stripe as well, but there are no effective way to
         * notify the LOD on the slave MDT, so we do not cache stripe
         * information for slave stripe for now. XXX*/
        lod_lov_stripe_cache_clear(l);
        LASSERT(buf != NULL && buf->lb_buf != NULL);
        lum = buf->lb_buf;

        rc = lod_verify_striping(d, buf, false);
        if (rc)
                RETURN(rc);

        if (lum->lmm_magic == LOV_USER_MAGIC_V3)
                v3 = buf->lb_buf;

        /* if { size, offset, count } = { 0, -1, 0 } and no pool
         * (i.e. all default values specified) then delete default
         * striping from dir. */
        CDEBUG(D_OTHER,
                "set default striping: sz %u # %u offset %d %s %s\n",
                (unsigned)lum->lmm_stripe_size,
                (unsigned)lum->lmm_stripe_count,
                (int)lum->lmm_stripe_offset,
                v3 ? "from" : "", v3 ? v3->lmm_pool_name : "");

        if (LOVEA_DELETE_VALUES((lum->lmm_stripe_size),
                                (lum->lmm_stripe_count),
                                (lum->lmm_stripe_offset)) &&
                        lum->lmm_magic == LOV_USER_MAGIC_V1) {
                rc = lod_xattr_del_internal(env, dt, name, th, capa);
                if (rc == -ENODATA)
                        rc = 0;
        } else {
                rc = lod_xattr_set_internal(env, dt, buf, name, fl, th, capa);
        }

        RETURN(rc);
}

/**
 * Set default striping on a directory object.
 *
 * Sets specified striping on a directory object unless it matches the default
 * striping (LOVEA_DELETE_VALUES() macro). In the latter case remove existing
 * EA. This striping will be used when a new directory is being created in the
 * directory.
 *
 * \param[in] env       execution environment
 * \param[in] dt        the striped object
 * \param[in] buf       buffer with the striping
 * \param[in] name      name of EA
 * \param[in] fl        xattr flag (see OSD API description)
 * \param[in] th        transaction handle
 * \param[in] capa      not used
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_xattr_set_default_lmv_on_dir(const struct lu_env *env,
                                            struct dt_object *dt,
                                            const struct lu_buf *buf,
                                            const char *name, int fl,
                                            struct thandle *th,
                                            struct lustre_capa *capa)
{
        struct lod_object       *l = lod_dt_obj(dt);
        struct lmv_user_md_v1   *lum;
        int                      rc;
        ENTRY;

        LASSERT(buf != NULL && buf->lb_buf != NULL);
        lum = buf->lb_buf;

        CDEBUG(D_OTHER, "set default stripe_count # %u stripe_offset %d\n",
              le32_to_cpu(lum->lum_stripe_count),
              (int)le32_to_cpu(lum->lum_stripe_offset));

        if (LMVEA_DELETE_VALUES((le32_to_cpu(lum->lum_stripe_count)),
                                 le32_to_cpu(lum->lum_stripe_offset)) &&
                                le32_to_cpu(lum->lum_magic) == LMV_USER_MAGIC) {
                rc = lod_xattr_del_internal(env, dt, name, th, capa);
                if (rc == -ENODATA)
                        rc = 0;
        } else {
                rc = lod_xattr_set_internal(env, dt, buf, name, fl, th, capa);
                if (rc != 0)
                        RETURN(rc);
        }

        /* Update default stripe cache */
        if (l->ldo_dir_stripe == NULL) {
                OBD_ALLOC_PTR(l->ldo_dir_stripe);
                if (l->ldo_dir_stripe == NULL)
                        RETURN(-ENOMEM);
        }

        l->ldo_dir_striping_cached = 0;
        l->ldo_dir_def_striping_set = 1;
        l->ldo_dir_def_stripenr = le32_to_cpu(lum->lum_stripe_count);

        RETURN(rc);
}

/**
 * Turn directory into a striped directory.
 *
 * During replay the client sends the striping created before MDT
 * failure, then the layer above LOD sends this defined striping
 * using ->do_xattr_set(), so LOD uses this method to replay creation
 * of the stripes. Notice the original information for the striping
 * (#stripes, FIDs, etc) was transfered in declare path.
 *
 * \param[in] env       execution environment
 * \param[in] dt        the striped object
 * \param[in] buf       not used currently
 * \param[in] name      not used currently
 * \param[in] fl        xattr flag (see OSD API description)
 * \param[in] th        transaction handle
 * \param[in] capa      not used
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_xattr_set_lmv(const struct lu_env *env, struct dt_object *dt,
                             const struct lu_buf *buf, const char *name,
                             int fl, struct thandle *th,
                             struct lustre_capa *capa)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lod_thread_info  *info = lod_env_info(env);
        struct lu_attr          *attr = &info->lti_attr;
        struct dt_object_format *dof = &info->lti_format;
        struct lu_buf           lmv_buf;
        struct lu_buf           slave_lmv_buf;
        struct lmv_mds_md_v1    *lmm;
        struct lmv_mds_md_v1    *slave_lmm = NULL;
        struct dt_insert_rec    *rec = &info->lti_dt_rec;
        int                     i;
        int                     rc;
        ENTRY;

        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr))
                RETURN(-ENOTDIR);

        /* The stripes are supposed to be allocated in declare phase,
         * if there are no stripes being allocated, it will skip */
        if (lo->ldo_stripenr == 0)
                RETURN(0);

        rc = dt_attr_get(env, dt_object_child(dt), attr, BYPASS_CAPA);
        if (rc != 0)
                RETURN(rc);

        attr->la_valid = LA_TYPE | LA_MODE;
        dof->dof_type = DFT_DIR;

        rc = lod_prep_lmv_md(env, dt, &lmv_buf);
        if (rc != 0)
                RETURN(rc);
        lmm = lmv_buf.lb_buf;

        OBD_ALLOC_PTR(slave_lmm);
        if (slave_lmm == NULL)
                RETURN(-ENOMEM);

        lod_prep_slave_lmv_md(slave_lmm, lmm);
        slave_lmv_buf.lb_buf = slave_lmm;
        slave_lmv_buf.lb_len = sizeof(*slave_lmm);

        rec->rec_type = S_IFDIR;
        for (i = 0; i < lo->ldo_stripenr; i++) {
                struct dt_object        *dto;
                char                    *stripe_name    = info->lti_key;
                struct lu_name          *sname;
                struct linkea_data       ldata          = { 0 };
                struct lu_buf            linkea_buf;

                dto = lo->ldo_stripe[i];
                dt_write_lock(env, dto, MOR_TGT_CHILD);
                rc = dt_create(env, dto, attr, NULL, dof, th);
                dt_write_unlock(env, dto);
                if (rc != 0)
                        RETURN(rc);

                rec->rec_fid = lu_object_fid(&dto->do_lu);
                rc = dt_insert(env, dto, (const struct dt_rec *)rec,
                               (const struct dt_key *)dot, th, capa, 0);
                if (rc != 0)
                        RETURN(rc);

                rec->rec_fid = lu_object_fid(&dt->do_lu);
                rc = dt_insert(env, dto, (struct dt_rec *)rec,
                               (const struct dt_key *)dotdot, th, capa, 0);
                if (rc != 0)
                        RETURN(rc);

                if (lo->ldo_striping_cached &&
                    !LOVEA_DELETE_VALUES(lo->ldo_def_stripe_size,
                                         lo->ldo_def_stripenr,
                                         lo->ldo_def_stripe_offset)) {
                        struct lov_user_md_v3   *v3;

                        /* sigh, lti_ea_store has been used for lmv_buf,
                         * so we have to allocate buffer for default
                         * stripe EA */
                        OBD_ALLOC_PTR(v3);
                        if (v3 == NULL)
                                GOTO(out, rc);

                        memset(v3, 0, sizeof(*v3));
                        v3->lmm_magic = cpu_to_le32(LOV_USER_MAGIC_V3);
                        v3->lmm_stripe_count =
                                cpu_to_le16(lo->ldo_def_stripenr);
                        v3->lmm_stripe_offset =
                                cpu_to_le16(lo->ldo_def_stripe_offset);
                        v3->lmm_stripe_size =
                                cpu_to_le32(lo->ldo_def_stripe_size);
                        if (lo->ldo_pool != NULL)
                                strlcpy(v3->lmm_pool_name, lo->ldo_pool,
                                        sizeof(v3->lmm_pool_name));

                        info->lti_buf.lb_buf = v3;
                        info->lti_buf.lb_len = sizeof(*v3);
                        rc = dt_xattr_set(env, dto, &info->lti_buf,
                                          XATTR_NAME_LOV, 0, th, capa);
                        OBD_FREE_PTR(v3);
                        if (rc != 0)
                                GOTO(out, rc);
                }

                slave_lmm->lmv_master_mdt_index = cpu_to_le32(i);
                rc = dt_xattr_set(env, dto, &slave_lmv_buf, XATTR_NAME_LMV,
                                  fl, th, capa);
                if (rc != 0)
                        GOTO(out, rc);

                snprintf(stripe_name, sizeof(info->lti_key), DFID":%d",
                         PFID(lu_object_fid(&dto->do_lu)), i);

                sname = lod_name_get(env, stripe_name, strlen(stripe_name));
                rc = linkea_data_new(&ldata, &info->lti_linkea_buf);
                if (rc != 0)
                        GOTO(out, rc);

                rc = linkea_add_buf(&ldata, sname, lu_object_fid(&dt->do_lu));
                if (rc != 0)
                        GOTO(out, rc);

                linkea_buf.lb_buf = ldata.ld_buf->lb_buf;
                linkea_buf.lb_len = ldata.ld_leh->leh_len;
                rc = dt_xattr_set(env, dto, &linkea_buf, XATTR_NAME_LINK,
                                  0, th, BYPASS_CAPA);
                if (rc != 0)
                        GOTO(out, rc);

                rec->rec_fid = lu_object_fid(&dto->do_lu);
                rc = dt_insert(env, dt_object_child(dt),
                               (const struct dt_rec *)rec,
                               (const struct dt_key *)stripe_name, th, capa, 0);
                if (rc != 0)
                        GOTO(out, rc);

                rc = dt_ref_add(env, dt_object_child(dt), th);
                if (rc != 0)
                        GOTO(out, rc);
        }

        rc = dt_xattr_set(env, dt_object_child(dt), &lmv_buf, XATTR_NAME_LMV,
                          fl, th, capa);

out:
        if (slave_lmm != NULL)
                OBD_FREE_PTR(slave_lmm);

        RETURN(rc);
}

/**
 * Helper function to declare/execute creation of a striped directory
 *
 * Called in declare/create object path, prepare striping for a directory
 * and prepare defaults data striping for the objects to be created in
 * that directory. Notice the function calls "declaration" or "execution"
 * methods depending on \a declare param. This is a consequence of the
 * current approach while we don't have natural distributed transactions:
 * we basically execute non-local updates in the declare phase. So, the
 * arguments for the both phases are the same and this is the reason for
 * this function to exist.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] attr      attributes the stripes will be created with
 * \param[in] dof       format of stripes (see OSD API description)
 * \param[in] th        transaction handle
 * \param[in] declare   where to call "declare" or "execute" methods
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
int lod_dir_striping_create_internal(const struct lu_env *env,
                                     struct dt_object *dt,
                                     struct lu_attr *attr,
                                     struct dt_object_format *dof,
                                     struct thandle *th,
                                     bool declare)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lod_object       *lo = lod_dt_obj(dt);
        int                     rc;
        ENTRY;

        if (!LMVEA_DELETE_VALUES(lo->ldo_stripenr,
                                 lo->ldo_dir_stripe_offset)) {
                struct lmv_user_md_v1 *v1 = info->lti_ea_store;
                int stripe_count = lo->ldo_stripenr;

                if (info->lti_ea_store_size < sizeof(*v1)) {
                        rc = lod_ea_store_resize(info, sizeof(*v1));
                        if (rc != 0)
                                RETURN(rc);
                        v1 = info->lti_ea_store;
                }

                memset(v1, 0, sizeof(*v1));
                v1->lum_magic = cpu_to_le32(LMV_USER_MAGIC);
                v1->lum_stripe_count = cpu_to_le32(stripe_count);
                v1->lum_stripe_offset =
                                cpu_to_le32(lo->ldo_dir_stripe_offset);

                info->lti_buf.lb_buf = v1;
                info->lti_buf.lb_len = sizeof(*v1);

                if (declare)
                        rc = lod_declare_xattr_set_lmv(env, dt, attr,
                                                       &info->lti_buf, dof, th);
                else
                        rc = lod_xattr_set_lmv(env, dt, &info->lti_buf,
                                               XATTR_NAME_LMV, 0, th,
                                               BYPASS_CAPA);
                if (rc != 0)
                        RETURN(rc);
        }

        /* Transfer default LMV striping from the parent */
        if (lo->ldo_dir_striping_cached &&
            !LMVEA_DELETE_VALUES(lo->ldo_dir_def_stripenr,
                                 lo->ldo_dir_def_stripe_offset)) {
                struct lmv_user_md_v1 *v1 = info->lti_ea_store;
                int def_stripe_count = lo->ldo_dir_def_stripenr;

                if (info->lti_ea_store_size < sizeof(*v1)) {
                        rc = lod_ea_store_resize(info, sizeof(*v1));
                        if (rc != 0)
                                RETURN(rc);
                        v1 = info->lti_ea_store;
                }

                memset(v1, 0, sizeof(*v1));
                v1->lum_magic = cpu_to_le32(LMV_USER_MAGIC);
                v1->lum_stripe_count = cpu_to_le32(def_stripe_count);
                v1->lum_stripe_offset =
                                cpu_to_le32(lo->ldo_dir_def_stripe_offset);
                v1->lum_hash_type =
                                cpu_to_le32(lo->ldo_dir_def_hash_type);

                info->lti_buf.lb_buf = v1;
                info->lti_buf.lb_len = sizeof(*v1);
                if (declare)
                        rc = lod_dir_declare_xattr_set(env, dt, &info->lti_buf,
                                                       XATTR_NAME_DEFAULT_LMV,
                                                       0, th);
                else
                        rc = lod_xattr_set_default_lmv_on_dir(env, dt,
                                                  &info->lti_buf,
                                                  XATTR_NAME_DEFAULT_LMV, 0,
                                                  th, BYPASS_CAPA);
                if (rc != 0)
                        RETURN(rc);
        }

        /* Transfer default LOV striping from the parent */
        if (lo->ldo_striping_cached &&
            !LOVEA_DELETE_VALUES(lo->ldo_def_stripe_size,
                                 lo->ldo_def_stripenr,
                                 lo->ldo_def_stripe_offset)) {
                struct lov_user_md_v3 *v3 = info->lti_ea_store;

                if (info->lti_ea_store_size < sizeof(*v3)) {
                        rc = lod_ea_store_resize(info, sizeof(*v3));
                        if (rc != 0)
                                RETURN(rc);
                        v3 = info->lti_ea_store;
                }

                memset(v3, 0, sizeof(*v3));
                v3->lmm_magic = cpu_to_le32(LOV_USER_MAGIC_V3);
                v3->lmm_stripe_count = cpu_to_le16(lo->ldo_def_stripenr);
                v3->lmm_stripe_offset = cpu_to_le16(lo->ldo_def_stripe_offset);
                v3->lmm_stripe_size = cpu_to_le32(lo->ldo_def_stripe_size);
                if (lo->ldo_pool != NULL)
                        strlcpy(v3->lmm_pool_name, lo->ldo_pool,
                                sizeof(v3->lmm_pool_name));

                info->lti_buf.lb_buf = v3;
                info->lti_buf.lb_len = sizeof(*v3);

                if (declare)
                        rc = lod_dir_declare_xattr_set(env, dt, &info->lti_buf,
                                                       XATTR_NAME_LOV, 0, th);
                else
                        rc = lod_xattr_set_lov_on_dir(env, dt, &info->lti_buf,
                                                      XATTR_NAME_LOV, 0, th,
                                                      BYPASS_CAPA);
                if (rc != 0)
                        RETURN(rc);
        }

        RETURN(0);
}

static int lod_declare_dir_striping_create(const struct lu_env *env,
                                           struct dt_object *dt,
                                           struct lu_attr *attr,
                                           struct dt_object_format *dof,
                                           struct thandle *th)
{
        return lod_dir_striping_create_internal(env, dt, attr, dof, th, true);
}

static int lod_dir_striping_create(const struct lu_env *env,
                                   struct dt_object *dt,
                                   struct lu_attr *attr,
                                   struct dt_object_format *dof,
                                   struct thandle *th)
{
        return lod_dir_striping_create_internal(env, dt, attr, dof, th, false);
}

/**
 * Implementation of dt_object_operations::do_xattr_set.
 *
 * Sets specified extended attribute on the object. Three types of EAs are
 * special:
 *   LOV EA - stores striping for a regular file or default striping (when set
 *            on a directory)
 *   LMV EA - stores a marker for the striped directories
 *   DMV EA - stores default directory striping
 *
 * When striping is applied to a non-striped existing object (this is called
 * late striping), then LOD notices the caller wants to turn the object into a
 * striped one. The stripe objects are created and appropriate EA is set:
 * LOV EA storing all the stripes directly or LMV EA storing just a small header
 * with striping configuration.
 *
 * \see dt_object_operations::do_xattr_set() in the API description for details.
 */
static int lod_xattr_set(const struct lu_env *env,
                         struct dt_object *dt, const struct lu_buf *buf,
                         const char *name, int fl, struct thandle *th,
                         struct lustre_capa *capa)
{
        struct dt_object        *next = dt_object_child(dt);
        int                      rc;
        ENTRY;

        if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
            strcmp(name, XATTR_NAME_LMV) == 0) {
                struct lmv_mds_md_v1 *lmm = buf->lb_buf;

                if (lmm != NULL && le32_to_cpu(lmm->lmv_hash_type) &
                                                LMV_HASH_FLAG_MIGRATION)
                        rc = dt_xattr_set(env, next, buf, name, fl, th, capa);
                else
                        rc = lod_dir_striping_create(env, dt, NULL, NULL, th);

                RETURN(rc);
        }

        if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
            strcmp(name, XATTR_NAME_LOV) == 0) {
                /* default LOVEA */
                rc = lod_xattr_set_lov_on_dir(env, dt, buf, name, fl, th, capa);
                RETURN(rc);
        } else if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
                   strcmp(name, XATTR_NAME_DEFAULT_LMV) == 0) {
                /* default LMVEA */
                rc = lod_xattr_set_default_lmv_on_dir(env, dt, buf, name, fl,
                                                      th, capa);
                RETURN(rc);
        } else if (S_ISREG(dt->do_lu.lo_header->loh_attr) &&
                   !strcmp(name, XATTR_NAME_LOV)) {
                /* in case of lov EA swap, just set it
                 * if not, it is a replay so check striping match what we
                 * already have during req replay, declare_xattr_set()
                 * defines striping, then create() does the work
                */
                if (fl & LU_XATTR_REPLACE) {
                        /* free stripes, then update disk */
                        lod_object_free_striping(env, lod_dt_obj(dt));
                        rc = dt_xattr_set(env, next, buf, name, fl, th, capa);
                } else {
                        rc = lod_striping_create(env, dt, NULL, NULL, th);
                }
                RETURN(rc);
        }

        /* then all other xattr */
        rc = lod_xattr_set_internal(env, dt, buf, name, fl, th, capa);

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_declare_xattr_del.
 *
 * \see dt_object_operations::do_declare_xattr_del() in the API description
 * for details.
 */
static int lod_declare_xattr_del(const struct lu_env *env,
                                 struct dt_object *dt, const char *name,
                                 struct thandle *th)
{
        return dt_declare_xattr_del(env, dt_object_child(dt), name, th);
}

/**
 * Implementation of dt_object_operations::do_xattr_del.
 *
 * If EA storing a regular striping is being deleted, then release
 * all the references to the stripe objects in core.
 *
 * \see dt_object_operations::do_xattr_del() in the API description for details.
 */
static int lod_xattr_del(const struct lu_env *env, struct dt_object *dt,
                         const char *name, struct thandle *th,
                         struct lustre_capa *capa)
{
        if (!strcmp(name, XATTR_NAME_LOV))
                lod_object_free_striping(env, lod_dt_obj(dt));
        return dt_xattr_del(env, dt_object_child(dt), name, th, capa);
}

/**
 * Implementation of dt_object_operations::do_xattr_list.
 *
 * \see dt_object_operations::do_xattr_list() in the API description
 * for details.
 */
static int lod_xattr_list(const struct lu_env *env,
                          struct dt_object *dt, struct lu_buf *buf,
                          struct lustre_capa *capa)
{
        return dt_xattr_list(env, dt_object_child(dt), buf, capa);
}

/**
 * Initialize a pool the object belongs to.
 *
 * When a striped object is being created, striping configuration
 * may demand the stripes are allocated on a limited set of the
 * targets. These limited sets are known as "pools". So we copy
 * a pool name into the object and later actual creation methods
 * (like lod_object_create()) will use this information to allocate
 * the stripes properly.
 *
 * \param[in] o         object
 * \param[in] pool      pool name
 */
int lod_object_set_pool(struct lod_object *o, char *pool)
{
        int len;

        if (o->ldo_pool) {
                len = strlen(o->ldo_pool);
                OBD_FREE(o->ldo_pool, len + 1);
                o->ldo_pool = NULL;
        }
        if (pool) {
                len = strlen(pool);
                OBD_ALLOC(o->ldo_pool, len + 1);
                if (o->ldo_pool == NULL)
                        return -ENOMEM;
                strcpy(o->ldo_pool, pool);
        }
        return 0;
}

static inline int lod_object_will_be_striped(int is_reg, const struct lu_fid *fid)
{
        return (is_reg && fid_seq(fid) != FID_SEQ_LOCAL_FILE);
}


/**
 * Cache default regular striping in the object.
 *
 * To improve performance of striped regular object creation we cache
 * default LOV striping (if it exists) in the parent directory object.
 *
 * \param[in] env               execution environment
 * \param[in] lp                object
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_cache_parent_lov_striping(const struct lu_env *env,
                                         struct lod_object *lp)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lov_user_md_v1   *v1 = NULL;
        struct lov_user_md_v3   *v3 = NULL;
        int                      rc;
        ENTRY;

        /* called from MDD without parent being write locked,
         * lock it here */
        dt_write_lock(env, dt_object_child(&lp->ldo_obj), 0);
        rc = lod_get_lov_ea(env, lp);
        if (rc < 0)
                GOTO(unlock, rc);

        if (rc < (typeof(rc))sizeof(struct lov_user_md)) {
                /* don't lookup for non-existing or invalid striping */
                lp->ldo_def_striping_set = 0;
                lp->ldo_striping_cached = 1;
                lp->ldo_def_stripe_size = 0;
                lp->ldo_def_stripenr = 0;
                lp->ldo_def_stripe_offset = (typeof(v1->lmm_stripe_offset))(-1);
                GOTO(unlock, rc = 0);
        }

        rc = 0;
        v1 = info->lti_ea_store;
        if (v1->lmm_magic == __swab32(LOV_USER_MAGIC_V1)) {
                lustre_swab_lov_user_md_v1(v1);
        } else if (v1->lmm_magic == __swab32(LOV_USER_MAGIC_V3)) {
                v3 = (struct lov_user_md_v3 *)v1;
                lustre_swab_lov_user_md_v3(v3);
        }

        if (v1->lmm_magic != LOV_MAGIC_V3 && v1->lmm_magic != LOV_MAGIC_V1)
                GOTO(unlock, rc = 0);

        if (v1->lmm_pattern != LOV_PATTERN_RAID0 && v1->lmm_pattern != 0)
                GOTO(unlock, rc = 0);

        CDEBUG(D_INFO, DFID" stripe_count=%d stripe_size=%d stripe_offset=%d\n",
               PFID(lu_object_fid(&lp->ldo_obj.do_lu)),
               (int)v1->lmm_stripe_count,
               (int)v1->lmm_stripe_size, (int)v1->lmm_stripe_offset);

        lp->ldo_def_stripenr = v1->lmm_stripe_count;
        lp->ldo_def_stripe_size = v1->lmm_stripe_size;
        lp->ldo_def_stripe_offset = v1->lmm_stripe_offset;
        lp->ldo_striping_cached = 1;
        lp->ldo_def_striping_set = 1;
        if (v1->lmm_magic == LOV_USER_MAGIC_V3) {
                /* XXX: sanity check here */
                v3 = (struct lov_user_md_v3 *) v1;
                if (v3->lmm_pool_name[0])
                        lod_object_set_pool(lp, v3->lmm_pool_name);
        }
        EXIT;
unlock:
        dt_write_unlock(env, dt_object_child(&lp->ldo_obj));
        return rc;
}


/**
 * Cache default directory striping in the object.
 *
 * To improve performance of striped directory creation we cache default
 * directory striping (if it exists) in the parent directory object.
 *
 * \param[in] env               execution environment
 * \param[in] lp                object
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_cache_parent_lmv_striping(const struct lu_env *env,
                                         struct lod_object *lp)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lmv_user_md_v1   *v1 = NULL;
        int                      rc;
        ENTRY;

        /* called from MDD without parent being write locked,
         * lock it here */
        dt_write_lock(env, dt_object_child(&lp->ldo_obj), 0);
        rc = lod_get_default_lmv_ea(env, lp);
        if (rc < 0)
                GOTO(unlock, rc);

        if (rc < (typeof(rc))sizeof(struct lmv_user_md)) {
                /* don't lookup for non-existing or invalid striping */
                lp->ldo_dir_def_striping_set = 0;
                lp->ldo_dir_striping_cached = 1;
                lp->ldo_dir_def_stripenr = 0;
                lp->ldo_dir_def_stripe_offset =
                                        (typeof(v1->lum_stripe_offset))(-1);
                lp->ldo_dir_def_hash_type = LMV_HASH_TYPE_FNV_1A_64;
                GOTO(unlock, rc = 0);
        }

        rc = 0;
        v1 = info->lti_ea_store;

        lp->ldo_dir_def_stripenr = le32_to_cpu(v1->lum_stripe_count);
        lp->ldo_dir_def_stripe_offset = le32_to_cpu(v1->lum_stripe_offset);
        lp->ldo_dir_def_hash_type = le32_to_cpu(v1->lum_hash_type);
        lp->ldo_dir_def_striping_set = 1;
        lp->ldo_dir_striping_cached = 1;

        EXIT;
unlock:
        dt_write_unlock(env, dt_object_child(&lp->ldo_obj));
        return rc;
}

/**
 * Cache default striping in the object.
 *
 * To improve performance of striped object creation we cache default striping
 * (if it exists) in the parent directory object. We always cache default
 * striping for the regular files (stored in LOV EA) and we cache default
 * striping for the directories if requested by \a child_mode (when a new
 * directory is being created).
 *
 * \param[in] env               execution environment
 * \param[in] lp                object
 * \param[in] child_mode        new object's mode
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_cache_parent_striping(const struct lu_env *env,
                                     struct lod_object *lp,
                                     umode_t child_mode)
{
        int rc = 0;
        ENTRY;

        rc = lod_load_striping(env, lp);
        if (rc != 0)
                RETURN(rc);

        if (!lp->ldo_striping_cached) {
                /* we haven't tried to get default striping for
                 * the directory yet, let's cache it in the object */
                rc = lod_cache_parent_lov_striping(env, lp);
                if (rc != 0)
                        RETURN(rc);
        }

        if (S_ISDIR(child_mode) && !lp->ldo_dir_striping_cached)
                rc = lod_cache_parent_lmv_striping(env, lp);

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_ah_init.
 *
 * This method is used to make a decision on the striping configuration for the
 * object being created. It can be taken from the \a parent object if it exists,
 * or filesystem's default. The resulting configuration (number of stripes,
 * stripe size/offset, pool name, etc) is stored in the object itself and will
 * be used by the methods like ->doo_declare_create().
 *
 * \see dt_object_operations::do_ah_init() in the API description for details.
 */
static void lod_ah_init(const struct lu_env *env,
                        struct dt_allocation_hint *ah,
                        struct dt_object *parent,
                        struct dt_object *child,
                        umode_t child_mode)
{
        struct lod_device *d = lu2lod_dev(child->do_lu.lo_dev);
        struct dt_object  *nextp = NULL;
        struct dt_object  *nextc;
        struct lod_object *lp = NULL;
        struct lod_object *lc;
        struct lov_desc   *desc;
        int               rc;
        ENTRY;

        LASSERT(child);

        if (likely(parent)) {
                nextp = dt_object_child(parent);
                lp = lod_dt_obj(parent);
                rc = lod_load_striping(env, lp);
                if (rc != 0)
                        return;
        }

        nextc = dt_object_child(child);
        lc = lod_dt_obj(child);

        LASSERT(lc->ldo_stripenr == 0);
        LASSERT(lc->ldo_stripe == NULL);

        /*
         * local object may want some hints
         * in case of late striping creation, ->ah_init()
         * can be called with local object existing
         */
        if (!dt_object_exists(nextc) || dt_object_remote(nextc))
                nextc->do_ops->do_ah_init(env, ah, dt_object_remote(nextp) ?
                                          NULL : nextp, nextc, child_mode);

        if (S_ISDIR(child_mode)) {
                if (lc->ldo_dir_stripe == NULL) {
                        OBD_ALLOC_PTR(lc->ldo_dir_stripe);
                        if (lc->ldo_dir_stripe == NULL)
                                return;
                }

                if (lp->ldo_dir_stripe == NULL) {
                        OBD_ALLOC_PTR(lp->ldo_dir_stripe);
                        if (lp->ldo_dir_stripe == NULL)
                                return;
                }

                rc = lod_cache_parent_striping(env, lp, child_mode);
                if (rc != 0)
                        return;

                /* transfer defaults to new directory */
                if (lp->ldo_striping_cached) {
                        if (lp->ldo_pool)
                                lod_object_set_pool(lc, lp->ldo_pool);
                        lc->ldo_def_stripenr = lp->ldo_def_stripenr;
                        lc->ldo_def_stripe_size = lp->ldo_def_stripe_size;
                        lc->ldo_def_stripe_offset = lp->ldo_def_stripe_offset;
                        lc->ldo_striping_cached = 1;
                        lc->ldo_def_striping_set = 1;
                        CDEBUG(D_OTHER, "inherite EA sz:%d off:%d nr:%d\n",
                               (int)lc->ldo_def_stripe_size,
                               (int)lc->ldo_def_stripe_offset,
                               (int)lc->ldo_def_stripenr);
                }

                /* transfer dir defaults to new directory */
                if (lp->ldo_dir_striping_cached) {
                        lc->ldo_dir_def_stripenr = lp->ldo_dir_def_stripenr;
                        lc->ldo_dir_def_stripe_offset =
                                                  lp->ldo_dir_def_stripe_offset;
                        lc->ldo_dir_def_hash_type =
                                                  lp->ldo_dir_def_hash_type;
                        lc->ldo_dir_striping_cached = 1;
                        lc->ldo_dir_def_striping_set = 1;
                        CDEBUG(D_INFO, "inherit default EA nr:%d off:%d t%u\n",
                               (int)lc->ldo_dir_def_stripenr,
                               (int)lc->ldo_dir_def_stripe_offset,
                               lc->ldo_dir_def_hash_type);
                }

                /* It should always honour the specified stripes */
                if (ah->dah_eadata != NULL && ah->dah_eadata_len != 0) {
                        const struct lmv_user_md_v1 *lum1 = ah->dah_eadata;

                        rc = lod_verify_md_striping(d, lum1);
                        if (rc == 0 &&
                                le32_to_cpu(lum1->lum_stripe_count) > 1) {
                                /* Directory will be striped only if
                                 * stripe_count > 1 */
                                lc->ldo_stripenr =
                                        le32_to_cpu(lum1->lum_stripe_count);
                                lc->ldo_dir_stripe_offset =
                                        le32_to_cpu(lum1->lum_stripe_offset);
                                lc->ldo_dir_hash_type =
                                        le32_to_cpu(lum1->lum_hash_type);
                                CDEBUG(D_INFO, "set stripe EA nr:%hu off:%d\n",
                                       lc->ldo_stripenr,
                                       (int)lc->ldo_dir_stripe_offset);
                        }
                /* then check whether there is default stripes from parent */
                } else if (lp->ldo_dir_def_striping_set) {
                        /* If there are default dir stripe from parent */
                        lc->ldo_stripenr = lp->ldo_dir_def_stripenr;
                        lc->ldo_dir_stripe_offset =
                                        lp->ldo_dir_def_stripe_offset;
                        lc->ldo_dir_hash_type =
                                        lp->ldo_dir_def_hash_type;
                        CDEBUG(D_INFO, "inherit EA nr:%hu off:%d\n",
                               lc->ldo_stripenr,
                               (int)lc->ldo_dir_stripe_offset);
                } else {
                        /* set default stripe for this directory */
                        lc->ldo_stripenr = 0;
                        lc->ldo_dir_stripe_offset = -1;
                }

                CDEBUG(D_INFO, "final striping count:%hu, offset:%d\n",
                       lc->ldo_stripenr, (int)lc->ldo_dir_stripe_offset);

                goto out;
        }

        /*
         * if object is going to be striped over OSTs, transfer default
         * striping information to the child, so that we can use it
         * during declaration and creation
         */
        if (!lod_object_will_be_striped(S_ISREG(child_mode),
                                        lu_object_fid(&child->do_lu)))
                goto out;
        /*
         * try from the parent
         */
        if (likely(parent)) {
                lod_cache_parent_striping(env, lp, child_mode);

                lc->ldo_def_stripe_offset = (__u16) -1;

                if (lp->ldo_def_striping_set) {
                        if (lp->ldo_pool)
                                lod_object_set_pool(lc, lp->ldo_pool);
                        lc->ldo_stripenr = lp->ldo_def_stripenr;
                        lc->ldo_stripe_size = lp->ldo_def_stripe_size;
                        lc->ldo_def_stripe_offset = lp->ldo_def_stripe_offset;
                        CDEBUG(D_OTHER, "striping from parent: #%d, sz %d %s\n",
                               lc->ldo_stripenr, lc->ldo_stripe_size,
                               lp->ldo_pool ? lp->ldo_pool : "");
                }
        }

        /*
         * if the parent doesn't provide with specific pattern, grab fs-wide one
         */
        desc = &d->lod_desc;
        if (lc->ldo_stripenr == 0)
                lc->ldo_stripenr = desc->ld_default_stripe_count;
        if (lc->ldo_stripe_size == 0)
                lc->ldo_stripe_size = desc->ld_default_stripe_size;
        CDEBUG(D_OTHER, "final striping: # %d stripes, sz %d from %s\n",
               lc->ldo_stripenr, lc->ldo_stripe_size,
               lc->ldo_pool ? lc->ldo_pool : "");

out:
        /* we do not cache stripe information for slave stripe, see
         * lod_xattr_set_lov_on_dir */
        if (lp != NULL && lp->ldo_dir_slave_stripe)
                lod_lov_stripe_cache_clear(lp);

        EXIT;
}

#define ll_do_div64(aaa,bbb)    do_div((aaa), (bbb))
/**
 * Size initialization on late striping.
 *
 * Propagate the size of a truncated object to a deferred striping.
 * This function handles a special case when truncate was done on a
 * non-striped object and now while the striping is being created
 * we can't lose that size, so we have to propagate it to the stripes
 * being created.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] th        transaction handle
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_declare_init_size(const struct lu_env *env,
                                 struct dt_object *dt, struct thandle *th)
{
        struct dt_object   *next = dt_object_child(dt);
        struct lod_object  *lo = lod_dt_obj(dt);
        struct lu_attr     *attr = &lod_env_info(env)->lti_attr;
        uint64_t            size, offs;
        int                 rc, stripe;
        ENTRY;

        /* XXX: we support the simplest (RAID0) striping so far */
        LASSERT(lo->ldo_stripe || lo->ldo_stripenr == 0);
        LASSERT(lo->ldo_stripe_size > 0);

        rc = dt_attr_get(env, next, attr, BYPASS_CAPA);
        LASSERT(attr->la_valid & LA_SIZE);
        if (rc)
                RETURN(rc);

        size = attr->la_size;
        if (size == 0)
                RETURN(0);

        /* ll_do_div64(a, b) returns a % b, and a = a / b */
        ll_do_div64(size, (__u64) lo->ldo_stripe_size);
        stripe = ll_do_div64(size, (__u64) lo->ldo_stripenr);

        size = size * lo->ldo_stripe_size;
        offs = attr->la_size;
        size += ll_do_div64(offs, lo->ldo_stripe_size);

        attr->la_valid = LA_SIZE;
        attr->la_size = size;

        rc = dt_declare_attr_set(env, lo->ldo_stripe[stripe], attr, th);

        RETURN(rc);
}

/**
 * Declare creation of striped object.
 *
 * The function declares creation stripes for a regular object. The function
 * also declares whether the stripes will be created with non-zero size if
 * previously size was set non-zero on the master object. If object \a dt is
 * not local, then only fully defined striping can be applied in \a lovea.
 * Otherwise \a lovea can be in the form of pattern, see lod_qos_parse_config()
 * for the details.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] attr      attributes the stripes will be created with
 * \param[in] lovea     a buffer containing striping description
 * \param[in] th        transaction handle
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
int lod_declare_striped_object(const struct lu_env *env, struct dt_object *dt,
                               struct lu_attr *attr,
                               const struct lu_buf *lovea, struct thandle *th)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct dt_object        *next = dt_object_child(dt);
        struct lod_object       *lo = lod_dt_obj(dt);
        int                      rc;
        ENTRY;

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_ALLOC_OBDO)) {
                /* failed to create striping, let's reset
                 * config so that others don't get confused */
                lod_object_free_striping(env, lo);
                GOTO(out, rc = -ENOMEM);
        }

        if (!dt_object_remote(next)) {
                /* choose OST and generate appropriate objects */
                rc = lod_qos_prep_create(env, lo, attr, lovea, th);
                if (rc) {
                        /* failed to create striping, let's reset
                         * config so that others don't get confused */
                        lod_object_free_striping(env, lo);
                        GOTO(out, rc);
                }

                /*
                 * declare storage for striping data
                 */
                info->lti_buf.lb_len = lov_mds_md_size(lo->ldo_stripenr,
                                lo->ldo_pool ?  LOV_MAGIC_V3 : LOV_MAGIC_V1);
        } else {
                /* LOD can not choose OST objects for remote objects, i.e.
                 * stripes must be ready before that. Right now, it can only
                 * happen during migrate, i.e. migrate process needs to create
                 * remote regular file (mdd_migrate_create), then the migrate
                 * process will provide stripeEA. */
                LASSERT(lovea != NULL);
                info->lti_buf = *lovea;
        }

        rc = dt_declare_xattr_set(env, next, &info->lti_buf,
                                  XATTR_NAME_LOV, 0, th);
        if (rc)
                GOTO(out, rc);

        /*
         * if striping is created with local object's size > 0,
         * we have to propagate this size to specific object
         * the case is possible only when local object was created previously
         */
        if (dt_object_exists(next))
                rc = lod_declare_init_size(env, dt, th);

out:
        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_declare_create.
 *
 * The method declares creation of a new object. If the object will be striped,
 * then helper functions are called to find FIDs for the stripes, declare
 * creation of the stripes and declare initialization of the striping
 * information to be stored in the master object.
 *
 * \see dt_object_operations::do_declare_create() in the API description
 * for details.
 */
static int lod_declare_object_create(const struct lu_env *env,
                                     struct dt_object *dt,
                                     struct lu_attr *attr,
                                     struct dt_allocation_hint *hint,
                                     struct dt_object_format *dof,
                                     struct thandle *th)
{
        struct dt_object   *next = dt_object_child(dt);
        struct lod_object  *lo = lod_dt_obj(dt);
        int                 rc;
        ENTRY;

        LASSERT(dof);
        LASSERT(attr);
        LASSERT(th);

        /*
         * first of all, we declare creation of local object
         */
        rc = dt_declare_create(env, next, attr, hint, dof, th);
        if (rc)
                GOTO(out, rc);

        if (dof->dof_type == DFT_SYM)
                dt->do_body_ops = &lod_body_lnk_ops;

        /*
         * it's lod_ah_init() who has decided the object will striped
         */
        if (dof->dof_type == DFT_REGULAR) {
                /* callers don't want stripes */
                /* XXX: all tricky interactions with ->ah_make_hint() decided
                 * to use striping, then ->declare_create() behaving differently
                 * should be cleaned */
                if (dof->u.dof_reg.striped == 0)
                        lo->ldo_stripenr = 0;
                if (lo->ldo_stripenr > 0)
                        rc = lod_declare_striped_object(env, dt, attr,
                                                        NULL, th);
        } else if (dof->dof_type == DFT_DIR) {
                /* Orphan object (like migrating object) does not have
                 * lod_dir_stripe, see lod_ah_init */
                if (lo->ldo_dir_stripe != NULL)
                        rc = lod_declare_dir_striping_create(env, dt, attr,
                                                             dof, th);
        }
out:
        RETURN(rc);
}

/**
 * Creation of a striped regular object.
 *
 * The function is called to create the stripe objects for a regular
 * striped file. This can happen at the initial object creation or
 * when the caller asks LOD to do so using ->do_xattr_set() method
 * (so called late striping). Notice all the information are already
 * prepared in the form of the list of objects (ldo_stripe field).
 * This is done during declare phase.
 *
 * \param[in] env       execution environment
 * \param[in] dt        object
 * \param[in] attr      attributes the stripes will be created with
 * \param[in] dof       format of stripes (see OSD API description)
 * \param[in] th        transaction handle
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
int lod_striping_create(const struct lu_env *env, struct dt_object *dt,
                        struct lu_attr *attr, struct dt_object_format *dof,
                        struct thandle *th)
{
        struct lod_object *lo = lod_dt_obj(dt);
        int                rc = 0, i;
        ENTRY;

        LASSERT(lo->ldo_striping_cached == 0);

        /* create all underlying objects */
        for (i = 0; i < lo->ldo_stripenr; i++) {
                LASSERT(lo->ldo_stripe[i]);
                rc = dt_create(env, lo->ldo_stripe[i], attr, NULL, dof, th);

                if (rc)
                        break;
        }
        if (rc == 0)
                rc = lod_generate_and_set_lovea(env, lo, th);

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_create.
 *
 * If any of preceeding methods (like ->do_declare_create(),
 * ->do_ah_init(), etc) chose to create a striped object,
 * then this method will create the master and the stripes.
 *
 * \see dt_object_operations::do_create() in the API description for details.
 */
static int lod_object_create(const struct lu_env *env, struct dt_object *dt,
                             struct lu_attr *attr,
                             struct dt_allocation_hint *hint,
                             struct dt_object_format *dof, struct thandle *th)
{
        struct dt_object   *next = dt_object_child(dt);
        struct lod_object  *lo = lod_dt_obj(dt);
        int                 rc;
        ENTRY;

        /* create local object */
        rc = dt_create(env, next, attr, hint, dof, th);
        if (rc != 0)
                RETURN(rc);

        if (S_ISREG(dt->do_lu.lo_header->loh_attr) &&
            lo->ldo_stripe && dof->u.dof_reg.striped != 0)
                rc = lod_striping_create(env, dt, attr, dof, th);

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_declare_destroy.
 *
 * If the object is a striped directory, then the function declares reference
 * removal from the master object (this is an index) to the stripes and declares
 * destroy of all the stripes. In all the cases, it declares an intention to
 * destroy the object itself.
 *
 * \see dt_object_operations::do_declare_destroy() in the API description
 * for details.
 */
static int lod_declare_object_destroy(const struct lu_env *env,
                                      struct dt_object *dt,
                                      struct thandle *th)
{
        struct dt_object   *next = dt_object_child(dt);
        struct lod_object  *lo = lod_dt_obj(dt);
        struct lod_thread_info *info = lod_env_info(env);
        char               *stripe_name = info->lti_key;
        int                 rc, i;
        ENTRY;

        /*
         * load striping information, notice we don't do this when object
         * is being initialized as we don't need this information till
         * few specific cases like destroy, chown
         */
        rc = lod_load_striping(env, lo);
        if (rc)
                RETURN(rc);

        /* declare destroy for all underlying objects */
        if (S_ISDIR(dt->do_lu.lo_header->loh_attr)) {
                rc = next->do_ops->do_index_try(env, next,
                                                &dt_directory_features);
                if (rc != 0)
                        RETURN(rc);

                for (i = 0; i < lo->ldo_stripenr; i++) {
                        rc = dt_declare_ref_del(env, next, th);
                        if (rc != 0)
                                RETURN(rc);
                        snprintf(stripe_name, sizeof(info->lti_key), DFID":%d",
                                PFID(lu_object_fid(&lo->ldo_stripe[i]->do_lu)),
                                i);
                        rc = dt_declare_delete(env, next,
                                        (const struct dt_key *)stripe_name, th);
                        if (rc != 0)
                                RETURN(rc);
                }
        }
        /*
         * we declare destroy for the local object
         */
        rc = dt_declare_destroy(env, next, th);
        if (rc)
                RETURN(rc);

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_LOST_MDTOBJ))
                RETURN(0);

        /* declare destroy all striped objects */
        for (i = 0; i < lo->ldo_stripenr; i++) {
                if (likely(lo->ldo_stripe[i] != NULL)) {
                        rc = dt_declare_destroy(env, lo->ldo_stripe[i], th);
                        if (rc != 0)
                                break;
                }
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_destroy.
 *
 * If the object is a striped directory, then the function removes references
 * from the master object (this is an index) to the stripes and destroys all
 * the stripes. In all the cases, the function destroys the object itself.
 *
 * \see dt_object_operations::do_destroy() in the API description for details.
 */
static int lod_object_destroy(const struct lu_env *env,
                struct dt_object *dt, struct thandle *th)
{
        struct dt_object  *next = dt_object_child(dt);
        struct lod_object *lo = lod_dt_obj(dt);
        struct lod_thread_info *info = lod_env_info(env);
        char               *stripe_name = info->lti_key;
        unsigned int       i;
        int                rc;
        ENTRY;

        /* destroy sub-stripe of master object */
        if (S_ISDIR(dt->do_lu.lo_header->loh_attr)) {
                rc = next->do_ops->do_index_try(env, next,
                                                &dt_directory_features);
                if (rc != 0)
                        RETURN(rc);

                for (i = 0; i < lo->ldo_stripenr; i++) {
                        rc = dt_ref_del(env, next, th);
                        if (rc != 0)
                                RETURN(rc);

                        snprintf(stripe_name, sizeof(info->lti_key), DFID":%d",
                                PFID(lu_object_fid(&lo->ldo_stripe[i]->do_lu)),
                                i);

                        CDEBUG(D_INFO, DFID" delete stripe %s "DFID"\n",
                               PFID(lu_object_fid(&dt->do_lu)), stripe_name,
                               PFID(lu_object_fid(&lo->ldo_stripe[i]->do_lu)));

                        rc = dt_delete(env, next,
                                       (const struct dt_key *)stripe_name,
                                       th, BYPASS_CAPA);
                        if (rc != 0)
                                RETURN(rc);
                }
        }
        rc = dt_destroy(env, next, th);
        if (rc != 0)
                RETURN(rc);

        if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_LOST_MDTOBJ))
                RETURN(0);

        /* destroy all striped objects */
        for (i = 0; i < lo->ldo_stripenr; i++) {
                if (likely(lo->ldo_stripe[i] != NULL) &&
                    (!OBD_FAIL_CHECK(OBD_FAIL_LFSCK_LOST_SPEOBJ) ||
                     i == cfs_fail_val)) {
                        rc = dt_destroy(env, lo->ldo_stripe[i], th);
                        if (rc != 0)
                                break;
                }
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_declare_ref_add.
 *
 * \see dt_object_operations::do_declare_ref_add() in the API description
 * for details.
 */
static int lod_declare_ref_add(const struct lu_env *env,
                               struct dt_object *dt, struct thandle *th)
{
        return dt_declare_ref_add(env, dt_object_child(dt), th);
}

/**
 * Implementation of dt_object_operations::do_ref_add.
 *
 * \see dt_object_operations::do_ref_add() in the API description for details.
 */
static int lod_ref_add(const struct lu_env *env,
                       struct dt_object *dt, struct thandle *th)
{
        return dt_ref_add(env, dt_object_child(dt), th);
}

/**
 * Implementation of dt_object_operations::do_declare_ref_del.
 *
 * \see dt_object_operations::do_declare_ref_del() in the API description
 * for details.
 */
static int lod_declare_ref_del(const struct lu_env *env,
                               struct dt_object *dt, struct thandle *th)
{
        return dt_declare_ref_del(env, dt_object_child(dt), th);
}

/**
 * Implementation of dt_object_operations::do_ref_del
 *
 * \see dt_object_operations::do_ref_del() in the API description for details.
 */
static int lod_ref_del(const struct lu_env *env,
                       struct dt_object *dt, struct thandle *th)
{
        return dt_ref_del(env, dt_object_child(dt), th);
}

/**
 * Implementation of dt_object_operations::do_capa_get.
 *
 * \see dt_object_operations::do_capa_get() in the API description for details.
 */
static struct obd_capa *lod_capa_get(const struct lu_env *env,
                                     struct dt_object *dt,
                                     struct lustre_capa *old, __u64 opc)
{
        return dt_capa_get(env, dt_object_child(dt), old, opc);
}

/**
 * Implementation of dt_object_operations::do_object_sync.
 *
 * \see dt_object_operations::do_object_sync() in the API description
 * for details.
 */
static int lod_object_sync(const struct lu_env *env, struct dt_object *dt,
                           __u64 start, __u64 end)
{
        return dt_object_sync(env, dt_object_child(dt), start, end);
}

struct lod_slave_locks  {
        int                     lsl_lock_count;
        struct lustre_handle    lsl_handle[0];
};

/**
 * Release LDLM locks on the stripes of a striped directory.
 *
 * Iterates over all the locks taken on the stripe objects and
 * release them using ->do_object_unlock() method.
 *
 * \param[in] env       execution environment
 * \param[in] dt        striped object
 * \param[in] einfo     lock description
 * \param[in] policy    data describing requested lock
 *
 * \retval              0 on success
 * \retval              negative if failed
 */
static int lod_object_unlock_internal(const struct lu_env *env,
                                      struct dt_object *dt,
                                      struct ldlm_enqueue_info *einfo,
                                      ldlm_policy_data_t *policy)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lod_slave_locks  *slave_locks = einfo->ei_cbdata;
        int                     rc = 0;
        int                     i;
        ENTRY;

        if (slave_locks == NULL)
                RETURN(0);

        for (i = 1; i < slave_locks->lsl_lock_count; i++) {
                if (lustre_handle_is_used(&slave_locks->lsl_handle[i])) {
                        int     rc1;

                        einfo->ei_cbdata = &slave_locks->lsl_handle[i];
                        rc1 = dt_object_unlock(env, lo->ldo_stripe[i], einfo,
                                               policy);
                        if (rc1 < 0)
                                rc = rc == 0 ? rc1 : rc;
                }
        }

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_object_unlock.
 *
 * Used to release LDLM lock(s).
 *
 * \see dt_object_operations::do_object_unlock() in the API description
 * for details.
 */
static int lod_object_unlock(const struct lu_env *env, struct dt_object *dt,
                             struct ldlm_enqueue_info *einfo,
                             union ldlm_policy_data *policy)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lod_slave_locks  *slave_locks = einfo->ei_cbdata;
        int                     slave_locks_size;
        int                     rc;
        ENTRY;

        if (slave_locks == NULL)
                RETURN(0);

        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr))
                RETURN(-ENOTDIR);

        rc = lod_load_striping(env, lo);
        if (rc != 0)
                RETURN(rc);

        /* Note: for remote lock for single stripe dir, MDT will cancel
         * the lock by lockh directly */
        if (lo->ldo_stripenr <= 1 && dt_object_remote(dt_object_child(dt)))
                RETURN(0);

        /* Only cancel slave lock for striped dir */
        rc = lod_object_unlock_internal(env, dt, einfo, policy);

        slave_locks_size = sizeof(*slave_locks) + slave_locks->lsl_lock_count *
                           sizeof(slave_locks->lsl_handle[0]);
        OBD_FREE(slave_locks, slave_locks_size);
        einfo->ei_cbdata = NULL;

        RETURN(rc);
}

/**
 * Implementation of dt_object_operations::do_object_lock.
 *
 * Used to get LDLM lock on the non-striped and striped objects.
 *
 * \see dt_object_operations::do_object_lock() in the API description
 * for details.
 */
static int lod_object_lock(const struct lu_env *env,
                           struct dt_object *dt,
                           struct lustre_handle *lh,
                           struct ldlm_enqueue_info *einfo,
                           union ldlm_policy_data *policy)
{
        struct lod_object       *lo = lod_dt_obj(dt);
        int                     rc = 0;
        int                     i;
        int                     slave_locks_size;
        struct lod_slave_locks  *slave_locks = NULL;
        ENTRY;

        /* remote object lock */
        if (!einfo->ei_enq_slave) {
                LASSERT(dt_object_remote(dt));
                return dt_object_lock(env, dt_object_child(dt), lh, einfo,
                                      policy);
        }

        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr))
                RETURN(-ENOTDIR);

        rc = lod_load_striping(env, lo);
        if (rc != 0)
                RETURN(rc);

        /* No stripes */
        if (lo->ldo_stripenr <= 1)
                RETURN(0);

        slave_locks_size = sizeof(*slave_locks) + lo->ldo_stripenr *
                           sizeof(slave_locks->lsl_handle[0]);
        /* Freed in lod_object_unlock */
        OBD_ALLOC(slave_locks, slave_locks_size);
        if (slave_locks == NULL)
                RETURN(-ENOMEM);
        slave_locks->lsl_lock_count = lo->ldo_stripenr;

        /* striped directory lock */
        for (i = 1; i < lo->ldo_stripenr; i++) {
                struct lustre_handle    lockh;
                struct ldlm_res_id      *res_id;

                res_id = &lod_env_info(env)->lti_res_id;
                fid_build_reg_res_name(lu_object_fid(&lo->ldo_stripe[i]->do_lu),
                                       res_id);
                einfo->ei_res_id = res_id;

                LASSERT(lo->ldo_stripe[i]);
                rc = dt_object_lock(env, lo->ldo_stripe[i], &lockh, einfo,
                                    policy);
                if (rc != 0)
                        GOTO(out, rc);
                slave_locks->lsl_handle[i] = lockh;
        }

        einfo->ei_cbdata = slave_locks;

out:
        if (rc != 0 && slave_locks != NULL) {
                einfo->ei_cbdata = slave_locks;
                lod_object_unlock_internal(env, dt, einfo, policy);
                OBD_FREE(slave_locks, slave_locks_size);
                einfo->ei_cbdata = NULL;
        }

        RETURN(rc);
}

struct dt_object_operations lod_obj_ops = {
        .do_read_lock           = lod_object_read_lock,
        .do_write_lock          = lod_object_write_lock,
        .do_read_unlock         = lod_object_read_unlock,
        .do_write_unlock        = lod_object_write_unlock,
        .do_write_locked        = lod_object_write_locked,
        .do_attr_get            = lod_attr_get,
        .do_declare_attr_set    = lod_declare_attr_set,
        .do_attr_set            = lod_attr_set,
        .do_xattr_get           = lod_xattr_get,
        .do_declare_xattr_set   = lod_declare_xattr_set,
        .do_xattr_set           = lod_xattr_set,
        .do_declare_xattr_del   = lod_declare_xattr_del,
        .do_xattr_del           = lod_xattr_del,
        .do_xattr_list          = lod_xattr_list,
        .do_ah_init             = lod_ah_init,
        .do_declare_create      = lod_declare_object_create,
        .do_create              = lod_object_create,
        .do_declare_destroy     = lod_declare_object_destroy,
        .do_destroy             = lod_object_destroy,
        .do_index_try           = lod_index_try,
        .do_declare_ref_add     = lod_declare_ref_add,
        .do_ref_add             = lod_ref_add,
        .do_declare_ref_del     = lod_declare_ref_del,
        .do_ref_del             = lod_ref_del,
        .do_capa_get            = lod_capa_get,
        .do_object_sync         = lod_object_sync,
        .do_object_lock         = lod_object_lock,
        .do_object_unlock       = lod_object_unlock,
};

/**
 * Implementation of dt_body_operations::dbo_read.
 *
 * \see dt_body_operations::dbo_read() in the API description for details.
 */
static ssize_t lod_read(const struct lu_env *env, struct dt_object *dt,
                        struct lu_buf *buf, loff_t *pos,
                        struct lustre_capa *capa)
{
        struct dt_object *next = dt_object_child(dt);
        return next->do_body_ops->dbo_read(env, next, buf, pos, capa);
}

/**
 * Implementation of dt_body_operations::dbo_declare_write.
 *
 * \see dt_body_operations::dbo_declare_write() in the API description
 * for details.
 */
static ssize_t lod_declare_write(const struct lu_env *env,
                                 struct dt_object *dt,
                                 const struct lu_buf *buf, loff_t pos,
                                 struct thandle *th)
{
        return dt_declare_record_write(env, dt_object_child(dt),
                                       buf, pos, th);
}

/**
 * Implementation of dt_body_operations::dbo_write.
 *
 * \see dt_body_operations::dbo_write() in the API description for details.
 */
static ssize_t lod_write(const struct lu_env *env, struct dt_object *dt,
                         const struct lu_buf *buf, loff_t *pos,
                         struct thandle *th, struct lustre_capa *capa, int iq)
{
        struct dt_object *next = dt_object_child(dt);
        LASSERT(next);
        return next->do_body_ops->dbo_write(env, next, buf, pos, th, capa, iq);
}

static const struct dt_body_operations lod_body_lnk_ops = {
        .dbo_read               = lod_read,
        .dbo_declare_write      = lod_declare_write,
        .dbo_write              = lod_write
};

/**
 * Implementation of lu_object_operations::loo_object_init.
 *
 * The function determines the type and the index of the target device using
 * sequence of the object's FID. Then passes control down to the
 * corresponding device:
 *  OSD for the local objects, OSP for remote
 *
 * \see lu_object_operations::loo_object_init() in the API description
 * for details.
 */
static int lod_object_init(const struct lu_env *env, struct lu_object *lo,
                           const struct lu_object_conf *conf)
{
        struct lod_device       *lod    = lu2lod_dev(lo->lo_dev);
        struct lu_device        *cdev   = NULL;
        struct lu_object        *cobj;
        struct lod_tgt_descs    *ltd    = NULL;
        struct lod_tgt_desc     *tgt;
        u32                      idx    = 0;
        int                      type   = LU_SEQ_RANGE_ANY;
        int                      rc;
        ENTRY;

        rc = lod_fld_lookup(env, lod, lu_object_fid(lo), &idx, &type);
        if (rc != 0)
                RETURN(rc);

        if (type == LU_SEQ_RANGE_MDT &&
            idx == lu_site2seq(lo->lo_dev->ld_site)->ss_node_id) {
                cdev = &lod->lod_child->dd_lu_dev;
        } else if (type == LU_SEQ_RANGE_MDT) {
                ltd = &lod->lod_mdt_descs;
                lod_getref(ltd);
        } else if (type == LU_SEQ_RANGE_OST) {
                ltd = &lod->lod_ost_descs;
                lod_getref(ltd);
        } else {
                LBUG();
        }

        if (ltd != NULL) {
                if (ltd->ltd_tgts_size > idx &&
                    cfs_bitmap_check(ltd->ltd_tgt_bitmap, idx)) {
                        tgt = LTD_TGT(ltd, idx);

                        LASSERT(tgt != NULL);
                        LASSERT(tgt->ltd_tgt != NULL);

                        cdev = &(tgt->ltd_tgt->dd_lu_dev);
                }
                lod_putref(lod, ltd);
        }

        if (unlikely(cdev == NULL))
                RETURN(-ENOENT);

        cobj = cdev->ld_ops->ldo_object_alloc(env, lo->lo_header, cdev);
        if (unlikely(cobj == NULL))
                RETURN(-ENOMEM);

        lu_object_add(lo, cobj);

        RETURN(0);
}

/**
 *
 * Release resources associated with striping.
 *
 * If the object is striped (regular or directory), then release
 * the stripe objects references and free the ldo_stripe array.
 *
 * \param[in] env       execution environment
 * \param[in] lo        object
 */
void lod_object_free_striping(const struct lu_env *env, struct lod_object *lo)
{
        int i;

        if (lo->ldo_dir_stripe != NULL) {
                OBD_FREE_PTR(lo->ldo_dir_stripe);
                lo->ldo_dir_stripe = NULL;
        }

        if (lo->ldo_stripe) {
                LASSERT(lo->ldo_stripes_allocated > 0);

                for (i = 0; i < lo->ldo_stripenr; i++) {
                        if (lo->ldo_stripe[i])
                                lu_object_put(env, &lo->ldo_stripe[i]->do_lu);
                }

                i = sizeof(struct dt_object *) * lo->ldo_stripes_allocated;
                OBD_FREE(lo->ldo_stripe, i);
                lo->ldo_stripe = NULL;
                lo->ldo_stripes_allocated = 0;
        }
        lo->ldo_stripenr = 0;
        lo->ldo_pattern = 0;
}

/**
 * Implementation of lu_object_operations::loo_object_start.
 *
 * \see lu_object_operations::loo_object_start() in the API description
 * for details.
 */
static int lod_object_start(const struct lu_env *env, struct lu_object *o)
{
        if (S_ISLNK(o->lo_header->loh_attr & S_IFMT))
                lu2lod_obj(o)->ldo_obj.do_body_ops = &lod_body_lnk_ops;
        return 0;
}

/**
 * Implementation of lu_object_operations::loo_object_free.
 *
 * \see lu_object_operations::loo_object_free() in the API description
 * for details.
 */
static void lod_object_free(const struct lu_env *env, struct lu_object *o)
{
        struct lod_object *mo = lu2lod_obj(o);

        /*
         * release all underlying object pinned
         */

        lod_object_free_striping(env, mo);

        lod_object_set_pool(mo, NULL);

        lu_object_fini(o);
        OBD_SLAB_FREE_PTR(mo, lod_object_kmem);
}

/**
 * Implementation of lu_object_operations::loo_object_release.
 *
 * \see lu_object_operations::loo_object_release() in the API description
 * for details.
 */
static void lod_object_release(const struct lu_env *env, struct lu_object *o)
{
        /* XXX: shouldn't we release everything here in case if object
         * creation failed before? */
}

/**
 * Implementation of lu_object_operations::loo_object_print.
 *
 * \see lu_object_operations::loo_object_print() in the API description
 * for details.
 */
static int lod_object_print(const struct lu_env *env, void *cookie,
                            lu_printer_t p, const struct lu_object *l)
{
        struct lod_object *o = lu2lod_obj((struct lu_object *) l);

        return (*p)(env, cookie, LUSTRE_LOD_NAME"-object@%p", o);
}

struct lu_object_operations lod_lu_obj_ops = {
        .loo_object_init        = lod_object_init,
        .loo_object_start       = lod_object_start,
        .loo_object_free        = lod_object_free,
        .loo_object_release     = lod_object_release,
        .loo_object_print       = lod_object_print,
};