[fs/lustre-release.git] / lustre / lod / lod_lov.c

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License version 2 for more details.  A copy is
 * included in the COPYING file that accompanied this code.
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright  2009 Sun Microsystems, Inc. All rights reserved
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2016, Intel Corporation.
 */
/*
 * lustre/lod/lod_lov.c
 *
 * A set of helpers to maintain Logical Object Volume (LOV)
 * Extended Attribute (EA) and known OST targets
 *
 * Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
 */

#define DEBUG_SUBSYSTEM S_MDS

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

#include "lod_internal.h"

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

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

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

                INIT_LIST_HEAD(&kill);

                cfs_foreach_bit(ltd->ltd_tgt_bitmap, idx) {
                        tgt_desc = LTD_TGT(ltd, idx);
                        LASSERT(tgt_desc);

                        if (!tgt_desc->ltd_reap)
                                continue;

                        list_add(&tgt_desc->ltd_kill, &kill);
                        LTD_TGT(ltd, idx) = NULL;
                        /*FIXME: only support ost pool for now */
                        if (ltd == &lod->lod_ost_descs) {
                                lod_ost_pool_remove(&lod->lod_pool_info, idx);
                                if (tgt_desc->ltd_active)
                                        lod->lod_desc.ld_active_tgt_count--;
                        }
                        ltd->ltd_tgtnr--;
                        cfs_bitmap_clear(ltd->ltd_tgt_bitmap, idx);
                        ltd->ltd_death_row--;
                }
                mutex_unlock(&ltd->ltd_mutex);
                up_read(&ltd->ltd_rw_sem);

                list_for_each_entry_safe(tgt_desc, tmp, &kill, ltd_kill) {
                        int rc;
                        list_del(&tgt_desc->ltd_kill);
                        if (ltd == &lod->lod_ost_descs) {
                                /* remove from QoS structures */
                                rc = qos_del_tgt(lod, tgt_desc);
                                if (rc)
                                        CERROR("%s: qos_del_tgt(%s) failed:"
                                               "rc = %d\n",
                                               lod2obd(lod)->obd_name,
                                              obd_uuid2str(&tgt_desc->ltd_uuid),
                                               rc);
                        }
                        rc = obd_disconnect(tgt_desc->ltd_exp);
                        if (rc)
                                CERROR("%s: failed to disconnect %s: rc = %d\n",
                                       lod2obd(lod)->obd_name,
                                       obd_uuid2str(&tgt_desc->ltd_uuid), rc);
                        OBD_FREE_PTR(tgt_desc);
                }
        } else {
                mutex_unlock(&ltd->ltd_mutex);
                up_read(&ltd->ltd_rw_sem);
        }
}

/**
 * Expand size of target table.
 *
 * When the target table is full, we have to extend the table. To do so,
 * we allocate new memory with some reserve, move data from the old table
 * to the new one and release memory consumed by the old table.
 * Notice we take ltd_rw_sem exclusively to ensure atomic switch.
 *
 * \param[in] ltd               target table
 * \param[in] newsize           new size of the table
 *
 * \retval                      0 on success
 * \retval                      -ENOMEM if reallocation failed
 */
static int ltd_bitmap_resize(struct lod_tgt_descs *ltd, __u32 newsize)
{
        struct cfs_bitmap *new_bitmap, *old_bitmap = NULL;
        int           rc = 0;
        ENTRY;

        /* grab write reference on the lod. Relocating the array requires
         * exclusive access */

        down_write(&ltd->ltd_rw_sem);
        if (newsize <= ltd->ltd_tgts_size)
                /* someone else has already resize the array */
                GOTO(out, rc = 0);

        /* allocate new bitmap */
        new_bitmap = CFS_ALLOCATE_BITMAP(newsize);
        if (!new_bitmap)
                GOTO(out, rc = -ENOMEM);

        if (ltd->ltd_tgts_size > 0) {
                /* the bitmap already exists, we need
                 * to copy data from old one */
                cfs_bitmap_copy(new_bitmap, ltd->ltd_tgt_bitmap);
                old_bitmap = ltd->ltd_tgt_bitmap;
        }

        ltd->ltd_tgts_size  = newsize;
        ltd->ltd_tgt_bitmap = new_bitmap;

        if (old_bitmap)
                CFS_FREE_BITMAP(old_bitmap);

        CDEBUG(D_CONFIG, "tgt size: %d\n", ltd->ltd_tgts_size);

        EXIT;
out:
        up_write(&ltd->ltd_rw_sem);
        return rc;
}

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

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

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

        obd_str2uuid(&obd_uuid, osp);

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

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

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

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

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

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

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

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

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

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

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

        lod_getref(ltd);
        if (index >= ltd->ltd_tgts_size) {
                /* we have to increase the size of the lod_osts array */
                __u32  newsize;

                newsize = max(ltd->ltd_tgts_size, (__u32)2);
                while (newsize < index + 1)
                        newsize = newsize << 1;

                /* lod_bitmap_resize() needs lod_rw_sem
                 * which we hold with th reference */
                lod_putref(lod, ltd);

                rc = ltd_bitmap_resize(ltd, newsize);
                if (rc)
                        GOTO(out_desc, rc);

                lod_getref(ltd);
        }

        mutex_lock(&ltd->ltd_mutex);
        lock = true;
        if (cfs_bitmap_check(ltd->ltd_tgt_bitmap, index)) {
                CERROR("%s: device %d is registered already\n", obd->obd_name,
                       index);
                GOTO(out_mutex, rc = -EEXIST);
        }

        if (ltd->ltd_tgt_idx[index / TGT_PTRS_PER_BLOCK] == NULL) {
                OBD_ALLOC_PTR(ltd->ltd_tgt_idx[index / TGT_PTRS_PER_BLOCK]);
                if (ltd->ltd_tgt_idx[index / TGT_PTRS_PER_BLOCK] == NULL) {
                        CERROR("can't allocate index to add %s\n",
                               obd->obd_name);
                        GOTO(out_mutex, rc = -ENOMEM);
                }
        }

        if (for_ost) {
                /* pool and qos are not supported for MDS stack yet */
                rc = lod_ost_pool_add(&lod->lod_pool_info, index,
                                      lod->lod_osts_size);
                if (rc) {
                        CERROR("%s: can't set up pool, failed with %d\n",
                               obd->obd_name, rc);
                        GOTO(out_mutex, rc);
                }

                rc = qos_add_tgt(lod, tgt_desc);
                if (rc) {
                        CERROR("%s: qos_add_tgt failed with %d\n",
                                obd->obd_name, rc);
                        GOTO(out_pool, rc);
                }

                /* The new OST is now a full citizen */
                if (index >= lod->lod_desc.ld_tgt_count)
                        lod->lod_desc.ld_tgt_count = index + 1;
                if (active)
                        lod->lod_desc.ld_active_tgt_count++;
        }

        LTD_TGT(ltd, index) = tgt_desc;
        cfs_bitmap_set(ltd->ltd_tgt_bitmap, index);
        ltd->ltd_tgtnr++;
        mutex_unlock(&ltd->ltd_mutex);
        lod_putref(lod, ltd);
        lock = false;
        if (lod->lod_recovery_completed)
                lu_dev->ld_ops->ldo_recovery_complete(env, lu_dev);

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

        rc = lfsck_add_target(env, lod->lod_child, dt_dev, exp, index, for_ost);
        if (rc != 0) {
                CERROR("Fail to add LFSCK target: name = %s, type = %s, "
                       "index = %u, rc = %d\n", osp, type, index, rc);
                GOTO(out_fini_llog, rc);
        }
        RETURN(rc);
out_fini_llog:
        lod_sub_fini_llog(env, tgt_desc->ltd_tgt,
                          tgt_desc->ltd_recovery_thread);
out_ltd:
        lod_getref(ltd);
        mutex_lock(&ltd->ltd_mutex);
        lock = true;
        if (!for_ost && LTD_TGT(ltd, index)->ltd_recovery_thread != NULL) {
                struct ptlrpc_thread *thread;

                thread = LTD_TGT(ltd, index)->ltd_recovery_thread;
                OBD_FREE_PTR(thread);
        }
        ltd->ltd_tgtnr--;
        cfs_bitmap_clear(ltd->ltd_tgt_bitmap, index);
        LTD_TGT(ltd, index) = NULL;
out_pool:
        lod_ost_pool_remove(&lod->lod_pool_info, index);
out_mutex:
        if (lock) {
                mutex_unlock(&ltd->ltd_mutex);
                lod_putref(lod, ltd);
        }
out_desc:
        OBD_FREE_PTR(tgt_desc);
out_conn:
        obd_disconnect(exp);
out_cleanup:
        /* XXX OSP needs us to send down LCFG_CLEANUP because it uses
         * objects from the MDT stack. See LU-7184. */
        lcfg = &lod_env_info(env)->lti_lustre_cfg;
        memset(lcfg, 0, sizeof(*lcfg));
        lcfg->lcfg_version = LUSTRE_CFG_VERSION;
        lcfg->lcfg_command = LCFG_CLEANUP;
        lu_dev->ld_ops->ldo_process_config(env, lu_dev, lcfg);

        return rc;
}

/**
 * Schedule target removal from the target table.
 *
 * Mark the device as dead. The device is not removed here because it may
 * still be in use. The device will be removed in lod_putref() when the
 * last reference is released.
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lod               LOD device the target table belongs to
 * \param[in] ltd               target table
 * \param[in] idx               index of the target
 * \param[in] for_ost           type of the target: 0 - MDT, 1 - OST
 */
static void __lod_del_device(const struct lu_env *env, struct lod_device *lod,
                             struct lod_tgt_descs *ltd, unsigned idx,
                             bool for_ost)
{
        LASSERT(LTD_TGT(ltd, idx));

        lfsck_del_target(env, lod->lod_child, LTD_TGT(ltd, idx)->ltd_tgt,
                         idx, for_ost);

        if (!for_ost && LTD_TGT(ltd, idx)->ltd_recovery_thread != NULL) {
                struct ptlrpc_thread *thread;

                thread = LTD_TGT(ltd, idx)->ltd_recovery_thread;
                OBD_FREE_PTR(thread);
        }

        if (LTD_TGT(ltd, idx)->ltd_reap == 0) {
                LTD_TGT(ltd, idx)->ltd_reap = 1;
                ltd->ltd_death_row++;
        }
}

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

        if (ltd->ltd_tgts_size <= 0)
                return 0;
        lod_getref(ltd);
        mutex_lock(&ltd->ltd_mutex);
        cfs_foreach_bit(ltd->ltd_tgt_bitmap, idx)
                __lod_del_device(env, lod, ltd, idx, for_ost);
        mutex_unlock(&ltd->ltd_mutex);
        lod_putref(lod, ltd);
        CFS_FREE_BITMAP(ltd->ltd_tgt_bitmap);
        for (idx = 0; idx < TGT_PTRS; idx++) {
                if (ltd->ltd_tgt_idx[idx])
                        OBD_FREE_PTR(ltd->ltd_tgt_idx[idx]);
        }
        ltd->ltd_tgts_size = 0;
        return 0;
}

/**
 * Remove device by name.
 *
 * Remove a device identified by \a osp from the target table. Given
 * the device can be in use, the real deletion happens in lod_putref().
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lod               LOD device to be connected to the new OSP
 * \param[in] ltd               target table
 * \param[in] osp               name of OSP device to be removed
 * \param[in] idx               index of the target
 * \param[in] gen               generation number, not used currently
 * \param[in] for_ost           type of the target: 0 - MDT, 1 - OST
 *
 * \retval                      0 if the device was scheduled for removal
 * \retval                      -EINVAL if no device was found
 */
int lod_del_device(const struct lu_env *env, struct lod_device *lod,
                   struct lod_tgt_descs *ltd, char *osp, unsigned idx,
                   unsigned gen, bool for_ost)
{
        struct obd_device *obd;
        int                rc = 0;
        struct obd_uuid    uuid;
        ENTRY;

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

        obd_str2uuid(&uuid, osp);

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

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

        obd_str2uuid(&uuid,  osp);

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

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

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

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

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

        LASSERT(round <=
                lov_mds_md_size(LOV_MAX_STRIPE_COUNT, LOV_MAGIC_V3));
        if (info->lti_ea_store) {
                LASSERT(info->lti_ea_store_size);
                LASSERT(info->lti_ea_store_size < round);
                CDEBUG(D_INFO, "EA store size %d is not enough, need %d\n",
                       info->lti_ea_store_size, round);
                OBD_FREE_LARGE(info->lti_ea_store, info->lti_ea_store_size);
                info->lti_ea_store = NULL;
                info->lti_ea_store_size = 0;
        }

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

        RETURN(0);
}

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

        for (i = 0; i < count; i++) {
                entry = &entries[i];
                if (entry->llc_pool != NULL)
                        lod_set_pool(&entry->llc_pool, NULL);
                LASSERT(entry->llc_stripe == NULL);
                LASSERT(entry->llc_stripes_allocated == 0);
        }

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

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

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

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

        if (new <= old)
                return 0;

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

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

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

        RETURN(0);
}

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

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

        OBD_ALLOC_LARGE(lo->ldo_comp_entries,
                        sizeof(*lo->ldo_comp_entries) * cnt);
        if (lo->ldo_comp_entries == NULL)
                return -ENOMEM;
        lo->ldo_comp_cnt = cnt;
        return 0;
}

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

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

        magic = lod_comp->llc_pool != NULL ? LOV_MAGIC_V3 : LOV_MAGIC_V1;
        if (lod_comp->llc_pattern == 0) /* default striping */
                lod_comp->llc_pattern = LOV_PATTERN_RAID0;

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

        lmm->lmm_stripe_size = cpu_to_le32(lod_comp->llc_stripe_size);
        lmm->lmm_stripe_count = cpu_to_le16(lod_comp->llc_stripenr);
        /* for dir, lmm_layout_gen stores default stripe offset. */
        lmm->lmm_layout_gen = is_dir ?
                        cpu_to_le16(lod_comp->llc_stripe_offset) :
                        cpu_to_le16(lod_comp->llc_layout_gen);

        if (magic == LOV_MAGIC_V1) {
                objs = &lmm->lmm_objects[0];
        } else {
                struct lov_mds_md_v3 *v3 = (struct lov_mds_md_v3 *)lmm;
                size_t cplen = strlcpy(v3->lmm_pool_name,
                                       lod_comp->llc_pool,
                                       sizeof(v3->lmm_pool_name));
                if (cplen >= sizeof(v3->lmm_pool_name))
                        RETURN(-E2BIG);
                objs = &v3->lmm_objects[0];
        }

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

        lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        for (i = 0; i < lod_comp->llc_stripenr; i++) {
                struct dt_object        *object;
                __u32   ost_idx;
                int     type = LU_SEQ_RANGE_OST;

                object = lod_comp->llc_stripe[i];
                LASSERT(object != NULL);
                info->lti_fid = *lu_object_fid(&object->do_lu);

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

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

                ostid_cpu_to_le(&info->lti_ostid, &objs[i].l_ost_oi);
                objs[i].l_ost_gen = cpu_to_le32(0);
                if (OBD_FAIL_CHECK(OBD_FAIL_MDS_FLD_LOOKUP))
                        rc = -ENOENT;
                else
                        rc = lod_fld_lookup(env, lod, &info->lti_fid,
                                            &ost_idx, &type);
                if (rc < 0) {
                        CERROR("%s: Can not locate "DFID": rc = %d\n",
                               lod2obd(lod)->obd_name, PFID(&info->lti_fid),
                               rc);
                        RETURN(rc);
                }
                objs[i].l_ost_idx = cpu_to_le32(ost_idx);
        }
done:
        if (lmm_size != NULL)
                *lmm_size = lov_mds_md_size(is_dir ?
                                0 : lod_comp->llc_stripenr, magic);
        RETURN(rc);
}

/**
 * Generate component ID for new created component.
 *
 * \param[in] lo                LOD object
 * \param[in] comp_idx          index of ldo_comp_entries
 *
 * \retval                      component ID on success
 * \retval                      LCME_ID_INVAL on failure
 */
static __u32 lod_gen_component_id(struct lod_object *lo, int comp_idx)
{
        struct lod_layout_component *lod_comp;
        __u32   id, start, end;
        int     i;

        LASSERT(lo->ldo_comp_entries[comp_idx].llc_id == LCME_ID_INVAL);

        lod_obj_inc_layout_gen(lo);
        id = lo->ldo_layout_gen;
        if (likely(id <= LCME_ID_MAX))
                return id;

        /* Layout generation wraps, need to check collisions. */
        start = id & LCME_ID_MASK;
        end = (__u32)LCME_ID_MAX + 1;
again:
        for (id = start; id < end; id++) {
                for (i = 0; i < lo->ldo_comp_cnt; i++) {
                        lod_comp = &lo->ldo_comp_entries[i];
                        if (id == lod_comp->llc_id)
                                break;
                }
                /* Found the ununsed ID */
                if (i == lo->ldo_comp_cnt)
                        return id;
        }
        if (end == (__u32)LCME_ID_MAX + 1) {
                start = 0;
                end = lo->ldo_layout_gen & LCME_ID_MASK;
                goto again;
        }

        return LCME_ID_INVAL;
}

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

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

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

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

        lcm = (struct lov_comp_md_v1 *)lmm;
        lcm->lcm_magic = cpu_to_le32(LOV_MAGIC_COMP_V1);
        lcm->lcm_entry_count = cpu_to_le16(comp_cnt);

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

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

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

                if (lod_comp->llc_id == LCME_ID_INVAL && !is_dir) {
                        lod_comp->llc_id = lod_gen_component_id(lo, i);
                        if (lod_comp->llc_id == LCME_ID_INVAL)
                                GOTO(out, rc = -ERANGE);
                }
                lcme->lcme_id = cpu_to_le32(lod_comp->llc_id);
                /* component must has been inistantiated */
                LASSERT(ergo(!is_dir, lod_comp->llc_flags & LCME_FL_INIT));
                lcme->lcme_flags = cpu_to_le32(lod_comp->llc_flags);
                lcme->lcme_extent.e_start =
                        cpu_to_le64(lod_comp->llc_extent.e_start);
                lcme->lcme_extent.e_end =
                        cpu_to_le64(lod_comp->llc_extent.e_end);
                lcme->lcme_offset = cpu_to_le32(offset);

                sub_md = (struct lov_mds_md *)((char *)lcm + offset);
                rc = lod_gen_component_ea(env, lo, i, sub_md, &size, is_dir);
                if (rc)
                        GOTO(out, rc);
                lcme->lcme_size = cpu_to_le32(size);
                offset += size;
                LASSERTF((offset <= *lmm_size) && (offset % sizeof(__u64) == 0),
                         "offset:%d lmm_size:%d\n", offset, *lmm_size);
        }
        lcm->lcm_size = cpu_to_le32(offset);
        lcm->lcm_layout_gen = cpu_to_le32(is_dir ? 0 : lo->ldo_layout_gen);

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

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

        LASSERT(info);

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

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

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

                LASSERT(rc > 0);
                rc = lod_ea_store_resize(info, rc);
                if (rc)
                        RETURN(rc);
                goto repeat;
        }

        RETURN(rc);
}

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

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

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

        return 0;
}

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

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

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

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

        stripe_len = lod_comp->llc_stripenr;
        OBD_ALLOC(stripe, sizeof(stripe[0]) * stripe_len);
        if (stripe == NULL)
                RETURN(-ENOMEM);

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

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

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

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

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

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

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

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

                OBD_FREE(stripe, sizeof(stripe[0]) * stripe_len);
                lod_comp->llc_stripenr = 0;
        } else {
                lod_comp->llc_stripe = stripe;
                lod_comp->llc_stripes_allocated = stripe_len;
        }

        RETURN(rc);
}

/**
 * Instantiate objects for striping.
 *
 * Parse striping information in \a buf and instantiate the objects
 * representing the stripes.
 *
 * \param[in] env               execution environment for this thread
 * \param[in] lo                LOD object
 * \param[in] buf               buffer storing LOV EA to parse
 *
 * \retval                      0 if parsing and objects creation succeed
 * \retval                      negative error number on failure
 */
int lod_parse_striping(const struct lu_env *env, struct lod_object *lo,
                       const struct lu_buf *buf)
{
        struct lov_mds_md_v1    *lmm;
        struct lov_comp_md_v1   *comp_v1 = NULL;
        struct lov_ost_data_v1  *objs;
        __u32   magic, pattern;
        int     i, rc = 0;
        __u16   comp_cnt;
        ENTRY;

        LASSERT(buf);
        LASSERT(buf->lb_buf);
        LASSERT(buf->lb_len);

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

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

        lod_free_comp_entries(lo);

        if (magic == LOV_MAGIC_COMP_V1) {
                comp_v1 = (struct lov_comp_md_v1 *)lmm;
                comp_cnt = le16_to_cpu(comp_v1->lcm_entry_count);
                if (comp_cnt == 0)
                        GOTO(out, rc = -EINVAL);
                lo->ldo_layout_gen = le32_to_cpu(comp_v1->lcm_layout_gen);
                lo->ldo_is_composite = 1;
        } else {
                comp_cnt = 1;
                lo->ldo_layout_gen = le16_to_cpu(lmm->lmm_layout_gen);
                lo->ldo_is_composite = 0;
        }

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

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

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

                        ext = &comp_v1->lcm_entries[i].lcme_extent;
                        lod_comp->llc_extent.e_start =
                                le64_to_cpu(ext->e_start);
                        lod_comp->llc_extent.e_end = le64_to_cpu(ext->e_end);
                        lod_comp->llc_flags =
                                le32_to_cpu(comp_v1->lcm_entries[i].lcme_flags);
                        lod_comp->llc_id =
                                le32_to_cpu(comp_v1->lcm_entries[i].lcme_id);
                        if (lod_comp->llc_id == LCME_ID_INVAL)
                                GOTO(out, rc = -EINVAL);
                } else {
                        lod_comp->llc_flags = LCME_FL_INIT;
                }

                pattern = le32_to_cpu(lmm->lmm_pattern);
                if (lov_pattern(pattern) != LOV_PATTERN_RAID0)
                        GOTO(out, rc = -EINVAL);

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

                if (magic == LOV_MAGIC_V3) {
                        struct lov_mds_md_v3 *v3 = (struct lov_mds_md_v3 *)lmm;
                        objs = &v3->lmm_objects[0];
                        /* no need to set pool, which is used in create only */
                } else {
                        objs = &lmm->lmm_objects[0];
                }

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

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

        if (S_ISDIR(lod2lu_obj(lo)->lo_header->loh_attr)) {
                if (lo->ldo_stripe != NULL)
                        return true;

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

        return false;
}

/**
 * Initialize the object representing the stripes.
 *
 * Unless the stripes are initialized already, fetch LOV (for regular
 * objects) or LMV (for directory objects) EA and call lod_parse_striping()
 * to instantiate the objects representing the stripes. Caller should
 * hold the dt_write_lock(next).
 *
 * \param[in] env               execution environment for this thread
 * \param[in,out] lo            LOD object
 *
 * \retval                      0 if parsing and object creation succeed
 * \retval                      negative error number on failure
 */
int lod_load_striping_locked(const struct lu_env *env, struct lod_object *lo)
{
        struct lod_thread_info  *info = lod_env_info(env);
        struct lu_buf           *buf  = &info->lti_buf;
        struct dt_object        *next = dt_object_child(&lo->ldo_obj);
        int                      rc = 0;
        ENTRY;

        if (!dt_object_exists(next))
                GOTO(out, rc = 0);

        if (lod_striping_loaded(lo))
                GOTO(out, rc = 0);

        if (S_ISREG(lod2lu_obj(lo)->lo_header->loh_attr)) {
                rc = lod_get_lov_ea(env, lo);
                if (rc <= 0)
                        GOTO(out, rc);
                /*
                 * there is LOV EA (striping information) in this object
                 * let's parse it and create in-core objects for the stripes
                 */
                buf->lb_buf = info->lti_ea_store;
                buf->lb_len = info->lti_ea_store_size;
                rc = lod_parse_striping(env, lo, buf);
                if (rc == 0)
                        lo->ldo_comp_cached = 1;
        } else if (S_ISDIR(lod2lu_obj(lo)->lo_header->loh_attr)) {
                rc = lod_get_lmv_ea(env, lo);
                if (rc < (typeof(rc))sizeof(struct lmv_mds_md_v1))
                        GOTO(out, rc = rc > 0 ? -EINVAL : rc);

                buf->lb_buf = info->lti_ea_store;
                buf->lb_len = info->lti_ea_store_size;
                if (rc == sizeof(struct lmv_mds_md_v1)) {
                        rc = lod_load_lmv_shards(env, lo, buf, true);
                        if (buf->lb_buf != info->lti_ea_store) {
                                OBD_FREE_LARGE(info->lti_ea_store,
                                               info->lti_ea_store_size);
                                info->lti_ea_store = buf->lb_buf;
                                info->lti_ea_store_size = buf->lb_len;
                        }

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

                /*
                 * there is LMV EA (striping information) in this object
                 * let's parse it and create in-core objects for the stripes
                 */
                rc = lod_parse_dir_striping(env, lo, buf);
        }
out:
        RETURN(rc);
}

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

        if (!dt_object_exists(next))
                return 0;

        /* Check without locking first */
        if (lod_striping_loaded(lo))
                return 0;

        /* currently this code is supposed to be called from declaration
         * phase only, thus the object is not expected to be locked by caller */
        dt_write_lock(env, next, 0);
        rc = lod_load_striping_locked(env, lo);
        dt_write_unlock(env, next);
        return rc;
}

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

        lum = buf->lb_buf;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        RETURN(rc);
}

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

        lum = buf->lb_buf;

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

        magic = le32_to_cpu(lum->lmm_magic) & ~LOV_MAGIC_DEF;
        if (magic != LOV_USER_MAGIC_V1 &&
            magic != LOV_USER_MAGIC_V3 &&
            magic != LOV_USER_MAGIC_SPECIFIC &&
            magic != LOV_USER_MAGIC_COMP_V1) {
                CDEBUG(D_LAYOUT, "bad userland LOV MAGIC: %#x\n",
                       le32_to_cpu(lum->lmm_magic));
                RETURN(-EINVAL);
        }

        if (magic == LOV_USER_MAGIC_COMP_V1) {
                struct lov_comp_md_entry_v1     *ent;
                struct lu_extent        *ext;
                struct lov_desc *desc = &d->lod_desc;
                struct lu_buf   tmp;
                __u32   stripe_size = 0;
                __u64   prev_end = start;

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

                if (le32_to_cpu(comp_v1->lcm_entry_count) == 0) {
                        CDEBUG(D_LAYOUT, "entry count is zero\n");
                        RETURN(-EINVAL);
                }

                for (i = 0; i < le32_to_cpu(comp_v1->lcm_entry_count); i++) {
                        ent = &comp_v1->lcm_entries[i];
                        ext = &ent->lcme_extent;

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

                        if (le64_to_cpu(ext->e_start) >=
                            le64_to_cpu(ext->e_end)) {
                                CDEBUG(D_LAYOUT, "invalid extent "
                                       "[%llu, %llu)\n",
                                       le64_to_cpu(ext->e_start),
                                       le64_to_cpu(ext->e_end));
                                RETURN(-EINVAL);
                        }

                        /* first component must start with 0, and the next
                         * must be adjacent with the previous one */
                        if (le64_to_cpu(ext->e_start) != prev_end) {
                                CDEBUG(D_LAYOUT, "invalid start "
                                       "actual:%llu, expect:%llu\n",
                                       le64_to_cpu(ext->e_start), prev_end);
                                RETURN(-EINVAL);
                        }
                        prev_end = le64_to_cpu(ext->e_end);

                        tmp.lb_buf = (char *)comp_v1 +
                                     le32_to_cpu(ent->lcme_offset);
                        tmp.lb_len = le32_to_cpu(ent->lcme_size);
                        rc = lod_verify_v1v3(d, &tmp, is_from_disk);
                        if (rc)
                                break;

                        lum = tmp.lb_buf;

                        /* extent end must be aligned with the stripe_size */
                        stripe_size = le32_to_cpu(lum->lmm_stripe_size);
                        if (stripe_size == 0)
                                stripe_size = desc->ld_default_stripe_size;
                        if (stripe_size == 0 ||
                            (prev_end != LUSTRE_EOF &&
                             (prev_end & (stripe_size - 1)))) {
                                CDEBUG(D_LAYOUT, "stripe size isn't aligned. "
                                       " stripe_sz: %u, [%llu, %llu)\n",
                                       stripe_size, ext->e_start, prev_end);
                                RETURN(-EINVAL);
                        }
                }
        } else {
                rc = lod_verify_v1v3(d, buf, is_from_disk);
        }

        RETURN(rc);
}

void lod_fix_desc_stripe_size(__u64 *val)
{
        if (*val < LOV_MIN_STRIPE_SIZE) {
                if (*val != 0)
                        LCONSOLE_INFO("Increasing default stripe size to "
                                      "minimum value %u\n",
                                      LOV_DESC_STRIPE_SIZE_DEFAULT);
                *val = LOV_DESC_STRIPE_SIZE_DEFAULT;
        } else if (*val & (LOV_MIN_STRIPE_SIZE - 1)) {
                *val &= ~(LOV_MIN_STRIPE_SIZE - 1);
                LCONSOLE_WARN("Changing default stripe size to %llu (a "
                              "multiple of %u)\n",
                              *val, LOV_MIN_STRIPE_SIZE);
        }
}

void lod_fix_desc_stripe_count(__u32 *val)
{
        if (*val == 0)
                *val = 1;
}

void lod_fix_desc_pattern(__u32 *val)
{
        /* from lov_setstripe */
        if ((*val != 0) && (*val != LOV_PATTERN_RAID0)) {
                LCONSOLE_WARN("Unknown stripe pattern: %#x\n", *val);
                *val = 0;
        }
}

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

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

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

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

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

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

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

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

        lod_fix_desc(desc);

        desc->ld_active_tgt_count = 0;
        lod->lod_desc = *desc;

        lod->lod_sp_me = LUSTRE_SP_CLI;

        /* Set up allocation policy (QoS and RR) */
        INIT_LIST_HEAD(&lod->lod_qos.lq_oss_list);
        init_rwsem(&lod->lod_qos.lq_rw_sem);
        lod->lod_qos.lq_dirty = 1;
        lod->lod_qos.lq_rr.lqr_dirty = 1;
        lod->lod_qos.lq_reset = 1;
        /* Default priority is toward free space balance */
        lod->lod_qos.lq_prio_free = 232;
        /* Default threshold for rr (roughly 17%) */
        lod->lod_qos.lq_threshold_rr = 43;

        /* Set up OST pool environment */
        lod->lod_pools_hash_body = cfs_hash_create("POOLS", HASH_POOLS_CUR_BITS,
                                                   HASH_POOLS_MAX_BITS,
                                                   HASH_POOLS_BKT_BITS, 0,
                                                   CFS_HASH_MIN_THETA,
                                                   CFS_HASH_MAX_THETA,
                                                   &pool_hash_operations,
                                                   CFS_HASH_DEFAULT);
        if (lod->lod_pools_hash_body == NULL)
                RETURN(-ENOMEM);

        INIT_LIST_HEAD(&lod->lod_pool_list);
        lod->lod_pool_count = 0;
        rc = lod_ost_pool_init(&lod->lod_pool_info, 0);
        if (rc)
                GOTO(out_hash, rc);
        lod_qos_rr_init(&lod->lod_qos.lq_rr);
        rc = lod_ost_pool_init(&lod->lod_qos.lq_rr.lqr_pool, 0);
        if (rc)
                GOTO(out_pool_info, rc);

        RETURN(0);

out_pool_info:
        lod_ost_pool_free(&lod->lod_pool_info);
out_hash:
        cfs_hash_putref(lod->lod_pools_hash_body);

        return rc;
}

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

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

        cfs_hash_putref(lod->lod_pools_hash_body);
        lod_ost_pool_free(&(lod->lod_qos.lq_rr.lqr_pool));
        lod_ost_pool_free(&lod->lod_pool_info);

        RETURN(0);
}