/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2014, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * Implementation of cl_object for LOV layer.
 *
 *   Author: Nikita Danilov <nikita.danilov@sun.com>
 *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
 */

#define DEBUG_SUBSYSTEM S_LOV

#include "lov_cl_internal.h"

/** \addtogroup lov
 *  @{
 */

/*****************************************************************************
 *
 * Layout operations.
 *
 */

struct lov_layout_operations {
        int (*llo_init)(const struct lu_env *env, struct lov_device *dev,
                        struct lov_object *lov,
                        const struct cl_object_conf *conf,
                        union lov_layout_state *state);
	int (*llo_delete)(const struct lu_env *env, struct lov_object *lov,
                           union lov_layout_state *state);
        void (*llo_fini)(const struct lu_env *env, struct lov_object *lov,
                         union lov_layout_state *state);
        void (*llo_install)(const struct lu_env *env, struct lov_object *lov,
                            union lov_layout_state *state);
        int  (*llo_print)(const struct lu_env *env, void *cookie,
                          lu_printer_t p, const struct lu_object *o);
        int  (*llo_page_init)(const struct lu_env *env, struct cl_object *obj,
			      struct cl_page *page, pgoff_t index);
        int  (*llo_lock_init)(const struct lu_env *env,
                              struct cl_object *obj, struct cl_lock *lock,
                              const struct cl_io *io);
        int  (*llo_io_init)(const struct lu_env *env,
                            struct cl_object *obj, struct cl_io *io);
        int  (*llo_getattr)(const struct lu_env *env, struct cl_object *obj,
                            struct cl_attr *attr);
	int  (*llo_find_cbdata)(const struct lu_env *env, struct cl_object *obj,
				ldlm_iterator_t iter, void *data);
};

static int lov_layout_wait(const struct lu_env *env, struct lov_object *lov);

struct lov_stripe_md *lov_lsm_get(struct cl_object *clobj)
{
	struct lu_object *luobj;
	struct lov_stripe_md *lsm = NULL;

	if (clobj == NULL)
		return NULL;

	luobj = lu_object_locate(&cl_object_header(clobj)->coh_lu,
				 &lov_device_type);
	if (luobj != NULL)
		lsm = lov_lsm_addref(lu2lov(luobj));
	return lsm;
}
EXPORT_SYMBOL(lov_lsm_get);

void lov_lsm_put(struct cl_object *unused, struct lov_stripe_md *lsm)
{
	if (lsm != NULL)
		lov_free_memmd(&lsm);
}
EXPORT_SYMBOL(lov_lsm_put);

/*****************************************************************************
 *
 * Lov object layout operations.
 *
 */

static void lov_install_empty(const struct lu_env *env,
                              struct lov_object *lov,
                              union  lov_layout_state *state)
{
        /*
         * File without objects.
         */
}

static int lov_init_empty(const struct lu_env *env,
                          struct lov_device *dev, struct lov_object *lov,
                          const struct cl_object_conf *conf,
                          union  lov_layout_state *state)
{
        return 0;
}

static void lov_install_raid0(const struct lu_env *env,
                              struct lov_object *lov,
                              union  lov_layout_state *state)
{
}

static struct cl_object *lov_sub_find(const struct lu_env *env,
                                      struct cl_device *dev,
                                      const struct lu_fid *fid,
                                      const struct cl_object_conf *conf)
{
        struct lu_object *o;

        ENTRY;
        o = lu_object_find_at(env, cl2lu_dev(dev), fid, &conf->coc_lu);
        LASSERT(ergo(!IS_ERR(o), o->lo_dev->ld_type == &lovsub_device_type));
        RETURN(lu2cl(o));
}

static int lov_init_sub(const struct lu_env *env, struct lov_object *lov,
			struct cl_object *stripe, struct lov_layout_raid0 *r0,
			int idx)
{
	struct cl_object_header *hdr;
	struct cl_object_header *subhdr;
	struct cl_object_header *parent;
	struct lov_oinfo        *oinfo;
	int result;

	if (OBD_FAIL_CHECK(OBD_FAIL_LOV_INIT)) {
		/* For sanity:test_206.
		 * Do not leave the object in cache to avoid accessing
		 * freed memory. This is because osc_object is referring to
		 * lov_oinfo of lsm_stripe_data which will be freed due to
		 * this failure. */
		cl_object_kill(env, stripe);
		cl_object_put(env, stripe);
		return -EIO;
	}

	hdr    = cl_object_header(lov2cl(lov));
	subhdr = cl_object_header(stripe);

	oinfo = lov->lo_lsm->lsm_oinfo[idx];
	CDEBUG(D_INODE, DFID"@%p[%d] -> "DFID"@%p: ostid: "DOSTID
	       " idx: %d gen: %d\n",
	       PFID(&subhdr->coh_lu.loh_fid), subhdr, idx,
	       PFID(&hdr->coh_lu.loh_fid), hdr, POSTID(&oinfo->loi_oi),
	       oinfo->loi_ost_idx, oinfo->loi_ost_gen);

	/* reuse ->coh_attr_guard to protect coh_parent change */
	spin_lock(&subhdr->coh_attr_guard);
	parent = subhdr->coh_parent;
	if (parent == NULL) {
		subhdr->coh_parent = hdr;
		spin_unlock(&subhdr->coh_attr_guard);
		subhdr->coh_nesting = hdr->coh_nesting + 1;
		lu_object_ref_add(&stripe->co_lu, "lov-parent", lov);
		r0->lo_sub[idx] = cl2lovsub(stripe);
		r0->lo_sub[idx]->lso_super = lov;
		r0->lo_sub[idx]->lso_index = idx;
		result = 0;
	} else {
		struct lu_object  *old_obj;
		struct lov_object *old_lov;
		unsigned int mask = D_INODE;

		spin_unlock(&subhdr->coh_attr_guard);
		old_obj = lu_object_locate(&parent->coh_lu, &lov_device_type);
		LASSERT(old_obj != NULL);
		old_lov = cl2lov(lu2cl(old_obj));
		if (old_lov->lo_layout_invalid) {
			/* the object's layout has already changed but isn't
			 * refreshed */
			lu_object_unhash(env, &stripe->co_lu);
			result = -EAGAIN;
		} else {
			mask = D_ERROR;
			result = -EIO;
		}

		LU_OBJECT_DEBUG(mask, env, &stripe->co_lu,
				"stripe %d is already owned.\n", idx);
		LU_OBJECT_DEBUG(mask, env, old_obj, "owned.\n");
		LU_OBJECT_HEADER(mask, env, lov2lu(lov), "try to own.\n");
		cl_object_put(env, stripe);
	}
	return result;
}

static int lov_page_slice_fixup(struct lov_object *lov,
				struct cl_object *stripe)
{
	struct cl_object_header *hdr = cl_object_header(&lov->lo_cl);
	struct cl_object *o;

	if (stripe == NULL)
		return hdr->coh_page_bufsize - lov->lo_cl.co_slice_off -
		       cfs_size_round(sizeof(struct lov_page));

	cl_object_for_each(o, stripe)
		o->co_slice_off += hdr->coh_page_bufsize;

	return cl_object_header(stripe)->coh_page_bufsize;
}

static int lov_init_raid0(const struct lu_env *env,
                          struct lov_device *dev, struct lov_object *lov,
                          const struct cl_object_conf *conf,
                          union  lov_layout_state *state)
{
        int result;
        int i;

        struct cl_object        *stripe;
        struct lov_thread_info  *lti     = lov_env_info(env);
        struct cl_object_conf   *subconf = &lti->lti_stripe_conf;
        struct lov_stripe_md    *lsm     = conf->u.coc_md->lsm;
        struct lu_fid           *ofid    = &lti->lti_fid;
        struct lov_layout_raid0 *r0      = &state->raid0;

        ENTRY;

	if (lsm->lsm_magic != LOV_MAGIC_V1 && lsm->lsm_magic != LOV_MAGIC_V3) {
		dump_lsm(D_ERROR, lsm);
		LASSERTF(0, "magic mismatch, expected %d/%d, actual %d.\n",
			 LOV_MAGIC_V1, LOV_MAGIC_V3, lsm->lsm_magic);
	}

	LASSERT(lov->lo_lsm == NULL);
	lov->lo_lsm = lsm_addref(lsm);
	r0->lo_nr  = lsm->lsm_stripe_count;
	LASSERT(r0->lo_nr <= lov_targets_nr(dev));

	lov->lo_layout_invalid = true;

	OBD_ALLOC_LARGE(r0->lo_sub, r0->lo_nr * sizeof r0->lo_sub[0]);
	if (r0->lo_sub != NULL) {
		int psz = 0;

		result = 0;
		subconf->coc_inode = conf->coc_inode;
		spin_lock_init(&r0->lo_sub_lock);
                /*
                 * Create stripe cl_objects.
                 */
                for (i = 0; i < r0->lo_nr && result == 0; ++i) {
                        struct cl_device *subdev;
                        struct lov_oinfo *oinfo = lsm->lsm_oinfo[i];
                        int ost_idx = oinfo->loi_ost_idx;

			if (lov_oinfo_is_dummy(oinfo))
				continue;

			result = ostid_to_fid(ofid, &oinfo->loi_oi,
					      oinfo->loi_ost_idx);
			if (result != 0)
				GOTO(out, result);

			subdev = lovsub2cl_dev(dev->ld_target[ost_idx]);
			subconf->u.coc_oinfo = oinfo;
			LASSERTF(subdev != NULL, "not init ost %d\n", ost_idx);
			/* In the function below, .hs_keycmp resolves to
			 * lu_obj_hop_keycmp() */
			/* coverity[overrun-buffer-val] */
			stripe = lov_sub_find(env, subdev, ofid, subconf);
			if (!IS_ERR(stripe)) {
				result = lov_init_sub(env, lov, stripe, r0, i);
				if (result == -EAGAIN) { /* try again */
					--i;
					result = 0;
					continue;
				}
			} else {
				result = PTR_ERR(stripe);
			}

			if (result == 0) {
				int sz = lov_page_slice_fixup(lov, stripe);
				LASSERT(ergo(psz > 0, psz == sz));
				psz = sz;
			}
                }
		if (result == 0)
			cl_object_header(&lov->lo_cl)->coh_page_bufsize += psz;
	} else
		result = -ENOMEM;
out:
	RETURN(result);
}

static int lov_init_released(const struct lu_env *env,
			struct lov_device *dev, struct lov_object *lov,
			const struct cl_object_conf *conf,
			union  lov_layout_state *state)
{
	struct lov_stripe_md *lsm = conf->u.coc_md->lsm;

	LASSERT(lsm != NULL);
	LASSERT(lsm_is_released(lsm));
	LASSERT(lov->lo_lsm == NULL);

	lov->lo_lsm = lsm_addref(lsm);
	return 0;
}

static struct cl_object *lov_find_subobj(const struct lu_env *env,
					 struct lov_object *lov,
					 struct lov_stripe_md *lsm,
					 int stripe_idx)
{
	struct lov_device	*dev = lu2lov_dev(lov2lu(lov)->lo_dev);
	struct lov_oinfo	*oinfo = lsm->lsm_oinfo[stripe_idx];
	struct lov_thread_info  *lti = lov_env_info(env);
	struct lu_fid		*ofid = &lti->lti_fid;
	struct cl_device	*subdev;
	int			ost_idx;
	int			rc;
	struct cl_object	*result;

	if (lov->lo_type != LLT_RAID0)
		GOTO(out, result = NULL);

	ost_idx = oinfo->loi_ost_idx;
	rc = ostid_to_fid(ofid, &oinfo->loi_oi, ost_idx);
	if (rc != 0)
		GOTO(out, result = NULL);

	subdev = lovsub2cl_dev(dev->ld_target[ost_idx]);
	result = lov_sub_find(env, subdev, ofid, NULL);
out:
	if (result == NULL)
		result = ERR_PTR(-EINVAL);
	return result;
}

static int lov_delete_empty(const struct lu_env *env, struct lov_object *lov,
			    union lov_layout_state *state)
{
	LASSERT(lov->lo_type == LLT_EMPTY || lov->lo_type == LLT_RELEASED);

	lov_layout_wait(env, lov);
	return 0;
}

static void lov_subobject_kill(const struct lu_env *env, struct lov_object *lov,
			       struct lovsub_object *los, int idx)
{
	struct cl_object        *sub;
	struct lov_layout_raid0 *r0;
	struct lu_site          *site;
	struct lu_site_bkt_data *bkt;
	wait_queue_t          *waiter;

        r0  = &lov->u.raid0;
        LASSERT(r0->lo_sub[idx] == los);

        sub  = lovsub2cl(los);
        site = sub->co_lu.lo_dev->ld_site;
        bkt  = lu_site_bkt_from_fid(site, &sub->co_lu.lo_header->loh_fid);

        cl_object_kill(env, sub);
        /* release a reference to the sub-object and ... */
        lu_object_ref_del(&sub->co_lu, "lov-parent", lov);
        cl_object_put(env, sub);

        /* ... wait until it is actually destroyed---sub-object clears its
         * ->lo_sub[] slot in lovsub_object_fini() */
	if (r0->lo_sub[idx] == los) {
		waiter = &lov_env_info(env)->lti_waiter;
		init_waitqueue_entry_current(waiter);
		add_wait_queue(&bkt->lsb_marche_funebre, waiter);
		set_current_state(TASK_UNINTERRUPTIBLE);
		while (1) {
			/* this wait-queue is signaled at the end of
			 * lu_object_free(). */
			set_current_state(TASK_UNINTERRUPTIBLE);
			spin_lock(&r0->lo_sub_lock);
			if (r0->lo_sub[idx] == los) {
				spin_unlock(&r0->lo_sub_lock);
				waitq_wait(waiter, TASK_UNINTERRUPTIBLE);
			} else {
				spin_unlock(&r0->lo_sub_lock);
				set_current_state(TASK_RUNNING);
				break;
			}
		}
		remove_wait_queue(&bkt->lsb_marche_funebre, waiter);
	}
	LASSERT(r0->lo_sub[idx] == NULL);
}

static int lov_delete_raid0(const struct lu_env *env, struct lov_object *lov,
			    union lov_layout_state *state)
{
	struct lov_layout_raid0 *r0 = &state->raid0;
	struct lov_stripe_md    *lsm = lov->lo_lsm;
	int i;

	ENTRY;

	dump_lsm(D_INODE, lsm);

	lov_layout_wait(env, lov);
        if (r0->lo_sub != NULL) {
                for (i = 0; i < r0->lo_nr; ++i) {
                        struct lovsub_object *los = r0->lo_sub[i];

                        if (los != NULL) {
				cl_object_prune(env, &los->lso_cl);
                                /*
                                 * If top-level object is to be evicted from
                                 * the cache, so are its sub-objects.
                                 */
                                lov_subobject_kill(env, lov, los, i);
			}
		}
	}
	RETURN(0);
}

static void lov_fini_empty(const struct lu_env *env, struct lov_object *lov,
                           union lov_layout_state *state)
{
	LASSERT(lov->lo_type == LLT_EMPTY || lov->lo_type == LLT_RELEASED);
}

static void lov_fini_raid0(const struct lu_env *env, struct lov_object *lov,
                           union lov_layout_state *state)
{
	struct lov_layout_raid0 *r0 = &state->raid0;
	ENTRY;

	if (r0->lo_sub != NULL) {
		OBD_FREE_LARGE(r0->lo_sub, r0->lo_nr * sizeof r0->lo_sub[0]);
		r0->lo_sub = NULL;
	}

	dump_lsm(D_INODE, lov->lo_lsm);
	lov_free_memmd(&lov->lo_lsm);

	EXIT;
}

static void lov_fini_released(const struct lu_env *env, struct lov_object *lov,
				union lov_layout_state *state)
{
	ENTRY;
	dump_lsm(D_INODE, lov->lo_lsm);
	lov_free_memmd(&lov->lo_lsm);
	EXIT;
}

static int lov_print_empty(const struct lu_env *env, void *cookie,
                           lu_printer_t p, const struct lu_object *o)
{
        (*p)(env, cookie, "empty %d\n", lu2lov(o)->lo_layout_invalid);
        return 0;
}

static int lov_print_raid0(const struct lu_env *env, void *cookie,
			   lu_printer_t p, const struct lu_object *o)
{
	struct lov_object	*lov = lu2lov(o);
	struct lov_layout_raid0	*r0  = lov_r0(lov);
	struct lov_stripe_md	*lsm = lov->lo_lsm;
	int			 i;

	(*p)(env, cookie, "stripes: %d, %s, lsm{%p 0x%08X %d %u %u}:\n",
		r0->lo_nr, lov->lo_layout_invalid ? "invalid" : "valid", lsm,
		lsm->lsm_magic, atomic_read(&lsm->lsm_refc),
		lsm->lsm_stripe_count, lsm->lsm_layout_gen);
	for (i = 0; i < r0->lo_nr; ++i) {
		struct lu_object *sub;

		if (r0->lo_sub[i] != NULL) {
			sub = lovsub2lu(r0->lo_sub[i]);
			lu_object_print(env, cookie, p, sub);
		} else {
			(*p)(env, cookie, "sub %d absent\n", i);
		}
	}
	return 0;
}

static int lov_print_released(const struct lu_env *env, void *cookie,
				lu_printer_t p, const struct lu_object *o)
{
	struct lov_object	*lov = lu2lov(o);
	struct lov_stripe_md	*lsm = lov->lo_lsm;

	(*p)(env, cookie,
		"released: %s, lsm{%p 0x%08X %d %u %u}:\n",
		lov->lo_layout_invalid ? "invalid" : "valid", lsm,
		lsm->lsm_magic, atomic_read(&lsm->lsm_refc),
		lsm->lsm_stripe_count, lsm->lsm_layout_gen);
	return 0;
}

/**
 * Implements cl_object_operations::coo_attr_get() method for an object
 * without stripes (LLT_EMPTY layout type).
 *
 * The only attributes this layer is authoritative in this case is
 * cl_attr::cat_blocks---it's 0.
 */
static int lov_attr_get_empty(const struct lu_env *env, struct cl_object *obj,
                              struct cl_attr *attr)
{
        attr->cat_blocks = 0;
        return 0;
}

static int lov_attr_get_raid0(const struct lu_env *env, struct cl_object *obj,
                              struct cl_attr *attr)
{
	struct lov_object	*lov = cl2lov(obj);
	struct lov_layout_raid0 *r0 = lov_r0(lov);
	struct cl_attr		*lov_attr = &r0->lo_attr;
	int			 result = 0;

        ENTRY;

	/* this is called w/o holding type guard mutex, so it must be inside
	 * an on going IO otherwise lsm may be replaced.
	 * LU-2117: it turns out there exists one exception. For mmaped files,
	 * the lock of those files may be requested in the other file's IO
	 * context, and this function is called in ccc_lock_state(), it will
	 * hit this assertion.
	 * Anyway, it's still okay to call attr_get w/o type guard as layout
	 * can't go if locks exist. */
	/* LASSERT(atomic_read(&lsm->lsm_refc) > 1); */

	if (!r0->lo_attr_valid) {
		struct lov_stripe_md    *lsm = lov->lo_lsm;
		struct ost_lvb          *lvb = &lov_env_info(env)->lti_lvb;
		__u64                    kms = 0;

		memset(lvb, 0, sizeof(*lvb));
		/* XXX: timestamps can be negative by sanity:test_39m,
		 * how can it be? */
		lvb->lvb_atime = LLONG_MIN;
		lvb->lvb_ctime = LLONG_MIN;
		lvb->lvb_mtime = LLONG_MIN;

		/*
		 * XXX that should be replaced with a loop over sub-objects,
		 * doing cl_object_attr_get() on them. But for now, let's
		 * reuse old lov code.
		 */

		/*
		 * XXX take lsm spin-lock to keep lov_merge_lvb_kms()
		 * happy. It's not needed, because new code uses
		 * ->coh_attr_guard spin-lock to protect consistency of
		 * sub-object attributes.
		 */
		lov_stripe_lock(lsm);
		result = lov_merge_lvb_kms(lsm, lvb, &kms);
		lov_stripe_unlock(lsm);
		if (result == 0) {
			cl_lvb2attr(lov_attr, lvb);
			lov_attr->cat_kms = kms;
			r0->lo_attr_valid = 1;
		}
	}
	if (result == 0) { /* merge results */
		attr->cat_blocks = lov_attr->cat_blocks;
		attr->cat_size = lov_attr->cat_size;
		attr->cat_kms = lov_attr->cat_kms;
		if (attr->cat_atime < lov_attr->cat_atime)
			attr->cat_atime = lov_attr->cat_atime;
		if (attr->cat_ctime < lov_attr->cat_ctime)
			attr->cat_ctime = lov_attr->cat_ctime;
		if (attr->cat_mtime < lov_attr->cat_mtime)
			attr->cat_mtime = lov_attr->cat_mtime;
	}
	RETURN(result);
}

static int lov_find_cbdata_empty(const struct lu_env *env,
				 struct cl_object *obj, ldlm_iterator_t iter,
				 void *data)
{
	return 0;
}

static int lov_find_cbdata_raid0(const struct lu_env *env,
				 struct cl_object *obj, ldlm_iterator_t iter,
				 void *data)
{
	struct lov_object	*lov = cl2lov(obj);
	struct lov_layout_raid0	*r0 = lov_r0(lov);
	struct cl_object	*subobj;
	int			i;
	int			rc = 0;

	for (i = 0; i < r0->lo_nr; ++i) {
		if (r0->lo_sub[i] == NULL)
			continue;

		subobj = lovsub2cl(r0->lo_sub[i]);

		rc = cl_object_find_cbdata(env, subobj, iter, data);
		if (rc != 0)
			break;
	}

	return rc;
}

const static struct lov_layout_operations lov_dispatch[] = {
        [LLT_EMPTY] = {
                .llo_init      = lov_init_empty,
                .llo_delete    = lov_delete_empty,
                .llo_fini      = lov_fini_empty,
                .llo_install   = lov_install_empty,
                .llo_print     = lov_print_empty,
                .llo_page_init = lov_page_init_empty,
                .llo_lock_init = lov_lock_init_empty,
                .llo_io_init   = lov_io_init_empty,
		.llo_getattr   = lov_attr_get_empty,
		.llo_find_cbdata = lov_find_cbdata_empty
        },
        [LLT_RAID0] = {
                .llo_init      = lov_init_raid0,
                .llo_delete    = lov_delete_raid0,
                .llo_fini      = lov_fini_raid0,
                .llo_install   = lov_install_raid0,
                .llo_print     = lov_print_raid0,
                .llo_page_init = lov_page_init_raid0,
                .llo_lock_init = lov_lock_init_raid0,
                .llo_io_init   = lov_io_init_raid0,
		.llo_getattr   = lov_attr_get_raid0,
		.llo_find_cbdata = lov_find_cbdata_raid0
	},
        [LLT_RELEASED] = {
                .llo_init      = lov_init_released,
                .llo_delete    = lov_delete_empty,
                .llo_fini      = lov_fini_released,
                .llo_install   = lov_install_empty,
                .llo_print     = lov_print_released,
                .llo_page_init = lov_page_init_empty,
                .llo_lock_init = lov_lock_init_empty,
                .llo_io_init   = lov_io_init_released,
		.llo_getattr   = lov_attr_get_empty,
		.llo_find_cbdata = lov_find_cbdata_empty
        }
};

/**
 * Performs a double-dispatch based on the layout type of an object.
 */
#define LOV_2DISPATCH_NOLOCK(obj, op, ...)                              \
({                                                                      \
        struct lov_object                      *__obj = (obj);          \
        enum lov_layout_type                    __llt;                  \
                                                                        \
        __llt = __obj->lo_type;                                         \
        LASSERT(0 <= __llt && __llt < ARRAY_SIZE(lov_dispatch));        \
        lov_dispatch[__llt].op(__VA_ARGS__);                            \
})

/**
 * Return lov_layout_type associated with a given lsm
 */
static enum lov_layout_type lov_type(struct lov_stripe_md *lsm)
{
	if (lsm == NULL)
		return LLT_EMPTY;
	if (lsm_is_released(lsm))
		return LLT_RELEASED;
	return LLT_RAID0;
}

static inline void lov_conf_freeze(struct lov_object *lov)
{
	if (lov->lo_owner != current)
		down_read(&lov->lo_type_guard);
}

static inline void lov_conf_thaw(struct lov_object *lov)
{
	if (lov->lo_owner != current)
		up_read(&lov->lo_type_guard);
}

#define LOV_2DISPATCH_MAYLOCK(obj, op, lock, ...)                       \
({                                                                      \
        struct lov_object                      *__obj = (obj);          \
        int                                     __lock = !!(lock);      \
        typeof(lov_dispatch[0].op(__VA_ARGS__)) __result;               \
                                                                        \
        if (__lock)                                                     \
                lov_conf_freeze(__obj);					\
        __result = LOV_2DISPATCH_NOLOCK(obj, op, __VA_ARGS__);          \
        if (__lock)                                                     \
                lov_conf_thaw(__obj);					\
        __result;                                                       \
})

/**
 * Performs a locked double-dispatch based on the layout type of an object.
 */
#define LOV_2DISPATCH(obj, op, ...)                     \
        LOV_2DISPATCH_MAYLOCK(obj, op, 1, __VA_ARGS__)

#define LOV_2DISPATCH_VOID(obj, op, ...)                                \
do {                                                                    \
        struct lov_object                      *__obj = (obj);          \
        enum lov_layout_type                    __llt;                  \
                                                                        \
	lov_conf_freeze(__obj);						\
        __llt = __obj->lo_type;                                         \
        LASSERT(0 <= __llt && __llt < ARRAY_SIZE(lov_dispatch));        \
        lov_dispatch[__llt].op(__VA_ARGS__);                            \
	lov_conf_thaw(__obj);						\
} while (0)

static void lov_conf_lock(struct lov_object *lov)
{
	LASSERT(lov->lo_owner != current);
	down_write(&lov->lo_type_guard);
	LASSERT(lov->lo_owner == NULL);
	lov->lo_owner = current;
}

static void lov_conf_unlock(struct lov_object *lov)
{
	lov->lo_owner = NULL;
	up_write(&lov->lo_type_guard);
}

static int lov_layout_wait(const struct lu_env *env, struct lov_object *lov)
{
	struct l_wait_info lwi = { 0 };
	ENTRY;

	while (atomic_read(&lov->lo_active_ios) > 0) {
		CDEBUG(D_INODE, "file:"DFID" wait for active IO, now: %d.\n",
			PFID(lu_object_fid(lov2lu(lov))),
			atomic_read(&lov->lo_active_ios));

		l_wait_event(lov->lo_waitq,
			     atomic_read(&lov->lo_active_ios) == 0, &lwi);
	}
	RETURN(0);
}

static int lov_layout_change(const struct lu_env *unused,
			     struct lov_object *lov,
			     const struct cl_object_conf *conf)
{
	int result;
	enum lov_layout_type llt = LLT_EMPTY;
	union lov_layout_state *state = &lov->u;
	const struct lov_layout_operations *old_ops;
	const struct lov_layout_operations *new_ops;

	void *cookie;
	struct lu_env *env;
	int refcheck;
	ENTRY;

	LASSERT(0 <= lov->lo_type && lov->lo_type < ARRAY_SIZE(lov_dispatch));

	if (conf->u.coc_md != NULL)
		llt = lov_type(conf->u.coc_md->lsm);
	LASSERT(0 <= llt && llt < ARRAY_SIZE(lov_dispatch));

	cookie = cl_env_reenter();
	env = cl_env_get(&refcheck);
	if (IS_ERR(env)) {
		cl_env_reexit(cookie);
		RETURN(PTR_ERR(env));
	}

	CDEBUG(D_INODE, DFID" from %s to %s\n",
	       PFID(lu_object_fid(lov2lu(lov))),
	       llt2str(lov->lo_type), llt2str(llt));

	old_ops = &lov_dispatch[lov->lo_type];
	new_ops = &lov_dispatch[llt];

	result = cl_object_prune(env, &lov->lo_cl);
	if (result != 0)
		GOTO(out, result);

	result = old_ops->llo_delete(env, lov, &lov->u);
	if (result == 0) {
		old_ops->llo_fini(env, lov, &lov->u);

		LASSERT(atomic_read(&lov->lo_active_ios) == 0);

		lov->lo_type = LLT_EMPTY;
		/* page bufsize fixup */
		cl_object_header(&lov->lo_cl)->coh_page_bufsize -=
			lov_page_slice_fixup(lov, NULL);

		result = new_ops->llo_init(env,
					lu2lov_dev(lov->lo_cl.co_lu.lo_dev),
					lov, conf, state);
		if (result == 0) {
			new_ops->llo_install(env, lov, state);
			lov->lo_type = llt;
		} else {
			new_ops->llo_delete(env, lov, state);
			new_ops->llo_fini(env, lov, state);
			/* this file becomes an EMPTY file. */
		}
	}

out:
	cl_env_put(env, &refcheck);
	cl_env_reexit(cookie);
	RETURN(result);
}

/*****************************************************************************
 *
 * Lov object operations.
 *
 */
int lov_object_init(const struct lu_env *env, struct lu_object *obj,
                    const struct lu_object_conf *conf)
{
        struct lov_device            *dev   = lu2lov_dev(obj->lo_dev);
        struct lov_object            *lov   = lu2lov(obj);
        const struct cl_object_conf  *cconf = lu2cl_conf(conf);
        union  lov_layout_state      *set   = &lov->u;
        const struct lov_layout_operations *ops;
        int result;

        ENTRY;
	init_rwsem(&lov->lo_type_guard);
	atomic_set(&lov->lo_active_ios, 0);
	init_waitqueue_head(&lov->lo_waitq);

	cl_object_page_init(lu2cl(obj), sizeof(struct lov_page));

        /* no locking is necessary, as object is being created */
	lov->lo_type = lov_type(cconf->u.coc_md->lsm);
        ops = &lov_dispatch[lov->lo_type];
        result = ops->llo_init(env, dev, lov, cconf, set);
        if (result == 0)
                ops->llo_install(env, lov, set);
        RETURN(result);
}

static int lov_conf_set(const struct lu_env *env, struct cl_object *obj,
                        const struct cl_object_conf *conf)
{
	struct lov_stripe_md	*lsm = NULL;
	struct lov_object	*lov = cl2lov(obj);
	int			 result = 0;
	ENTRY;

	lov_conf_lock(lov);
	if (conf->coc_opc == OBJECT_CONF_INVALIDATE) {
		lov->lo_layout_invalid = true;
		GOTO(out, result = 0);
	}

	if (conf->coc_opc == OBJECT_CONF_WAIT) {
		if (lov->lo_layout_invalid &&
		    atomic_read(&lov->lo_active_ios) > 0) {
			lov_conf_unlock(lov);
			result = lov_layout_wait(env, lov);
			lov_conf_lock(lov);
		}
		GOTO(out, result);
	}

	LASSERT(conf->coc_opc == OBJECT_CONF_SET);

	if (conf->u.coc_md != NULL)
		lsm = conf->u.coc_md->lsm;
	if ((lsm == NULL && lov->lo_lsm == NULL) ||
	    ((lsm != NULL && lov->lo_lsm != NULL) &&
	     (lov->lo_lsm->lsm_layout_gen == lsm->lsm_layout_gen) &&
	     (lov->lo_lsm->lsm_pattern == lsm->lsm_pattern))) {
		/* same version of layout */
		lov->lo_layout_invalid = false;
		GOTO(out, result = 0);
	}

	/* will change layout - check if there still exists active IO. */
	if (atomic_read(&lov->lo_active_ios) > 0) {
		lov->lo_layout_invalid = true;
		GOTO(out, result = -EBUSY);
	}

	result = lov_layout_change(env, lov, conf);
	lov->lo_layout_invalid = result != 0;
	EXIT;

out:
	lov_conf_unlock(lov);
	CDEBUG(D_INODE, DFID" lo_layout_invalid=%d\n",
	       PFID(lu_object_fid(lov2lu(lov))), lov->lo_layout_invalid);
	RETURN(result);
}

static void lov_object_delete(const struct lu_env *env, struct lu_object *obj)
{
        struct lov_object *lov = lu2lov(obj);

        ENTRY;
        LOV_2DISPATCH_VOID(lov, llo_delete, env, lov, &lov->u);
        EXIT;
}

static void lov_object_free(const struct lu_env *env, struct lu_object *obj)
{
        struct lov_object *lov = lu2lov(obj);

        ENTRY;
        LOV_2DISPATCH_VOID(lov, llo_fini, env, lov, &lov->u);
        lu_object_fini(obj);
        OBD_SLAB_FREE_PTR(lov, lov_object_kmem);
        EXIT;
}

static int lov_object_print(const struct lu_env *env, void *cookie,
                            lu_printer_t p, const struct lu_object *o)
{
        return LOV_2DISPATCH_NOLOCK(lu2lov(o), llo_print, env, cookie, p, o);
}

int lov_page_init(const struct lu_env *env, struct cl_object *obj,
		  struct cl_page *page, pgoff_t index)
{
	return LOV_2DISPATCH_NOLOCK(cl2lov(obj), llo_page_init, env, obj, page,
				    index);
}

/**
 * Implements cl_object_operations::clo_io_init() method for lov
 * layer. Dispatches to the appropriate layout io initialization method.
 */
int lov_io_init(const struct lu_env *env, struct cl_object *obj,
		struct cl_io *io)
{
	CL_IO_SLICE_CLEAN(lov_env_io(env), lis_cl);
	return LOV_2DISPATCH_MAYLOCK(cl2lov(obj), llo_io_init,
				     !io->ci_ignore_layout, env, obj, io);
}

/**
 * An implementation of cl_object_operations::clo_attr_get() method for lov
 * layer. For raid0 layout this collects and merges attributes of all
 * sub-objects.
 */
static int lov_attr_get(const struct lu_env *env, struct cl_object *obj,
                        struct cl_attr *attr)
{
        /* do not take lock, as this function is called under a
         * spin-lock. Layout is protected from changing by ongoing IO. */
        return LOV_2DISPATCH_NOLOCK(cl2lov(obj), llo_getattr, env, obj, attr);
}

static int lov_attr_update(const struct lu_env *env, struct cl_object *obj,
			   const struct cl_attr *attr, unsigned valid)
{
	/*
	 * No dispatch is required here, as no layout implements this.
	 */
	return 0;
}

int lov_lock_init(const struct lu_env *env, struct cl_object *obj,
		  struct cl_lock *lock, const struct cl_io *io)
{
	/* No need to lock because we've taken one refcount of layout.  */
	return LOV_2DISPATCH_NOLOCK(cl2lov(obj), llo_lock_init, env, obj, lock,
				    io);
}

/**
 * We calculate on which OST the mapping will end. If the length of mapping
 * is greater than (stripe_size * stripe_count) then the last_stripe will
 * will be one just before start_stripe. Else we check if the mapping
 * intersects each OST and find last_stripe.
 * This function returns the last_stripe and also sets the stripe_count
 * over which the mapping is spread
 *
 * \param lsm [in]		striping information for the file
 * \param fm_start [in]		logical start of mapping
 * \param fm_end [in]		logical end of mapping
 * \param start_stripe [in]	starting stripe of the mapping
 * \param stripe_count [out]	the number of stripes across which to map is
 *				returned
 *
 * \retval last_stripe		return the last stripe of the mapping
 */
static int fiemap_calc_last_stripe(struct lov_stripe_md *lsm,
				   loff_t fm_start, loff_t fm_end,
				   int start_stripe, int *stripe_count)
{
	int last_stripe;
	loff_t obd_start;
	loff_t obd_end;
	int i, j;

	if (fm_end - fm_start > lsm->lsm_stripe_size * lsm->lsm_stripe_count) {
		last_stripe = (start_stripe < 1 ? lsm->lsm_stripe_count - 1 :
							      start_stripe - 1);
		*stripe_count = lsm->lsm_stripe_count;
	} else {
		for (j = 0, i = start_stripe; j < lsm->lsm_stripe_count;
		     i = (i + 1) % lsm->lsm_stripe_count, j++) {
			if ((lov_stripe_intersects(lsm, i, fm_start, fm_end,
						   &obd_start, &obd_end)) == 0)
				break;
		}
		*stripe_count = j;
		last_stripe = (start_stripe + j - 1) % lsm->lsm_stripe_count;
	}

	return last_stripe;
}

/**
 * Set fe_device and copy extents from local buffer into main return buffer.
 *
 * \param fiemap [out]		fiemap to hold all extents
 * \param lcl_fm_ext [in]	array of fiemap extents get from OSC layer
 * \param ost_index [in]	OST index to be written into the fm_device
 *				field for each extent
 * \param ext_count [in]	number of extents to be copied
 * \param current_extent [in]	where to start copying in the extent array
 */
static void fiemap_prepare_and_copy_exts(struct fiemap *fiemap,
					 struct ll_fiemap_extent *lcl_fm_ext,
					 int ost_index, unsigned int ext_count,
					 int current_extent)
{
	char		*to;
	unsigned int	ext;

	for (ext = 0; ext < ext_count; ext++) {
		lcl_fm_ext[ext].fe_device = ost_index;
		lcl_fm_ext[ext].fe_flags |= FIEMAP_EXTENT_NET;
	}

	/* Copy fm_extent's from fm_local to return buffer */
	to = (char *)fiemap + fiemap_count_to_size(current_extent);
	memcpy(to, lcl_fm_ext, ext_count * sizeof(struct ll_fiemap_extent));
}

#define FIEMAP_BUFFER_SIZE 4096

/**
 * Non-zero fe_logical indicates that this is a continuation FIEMAP
 * call. The local end offset and the device are sent in the first
 * fm_extent. This function calculates the stripe number from the index.
 * This function returns a stripe_no on which mapping is to be restarted.
 *
 * This function returns fm_end_offset which is the in-OST offset at which
 * mapping should be restarted. If fm_end_offset=0 is returned then caller
 * will re-calculate proper offset in next stripe.
 * Note that the first extent is passed to lov_get_info via the value field.
 *
 * \param fiemap [in]		fiemap request header
 * \param lsm [in]		striping information for the file
 * \param fm_start [in]		logical start of mapping
 * \param fm_end [in]		logical end of mapping
 * \param start_stripe [out]	starting stripe will be returned in this
 */
static loff_t fiemap_calc_fm_end_offset(struct fiemap *fiemap,
					struct lov_stripe_md *lsm,
					loff_t fm_start, loff_t fm_end,
					int *start_stripe)
{
	loff_t local_end = fiemap->fm_extents[0].fe_logical;
	loff_t lun_start;
	loff_t lun_end;
	loff_t fm_end_offset;
	int stripe_no = -1;
	int i;

	if (fiemap->fm_extent_count == 0 ||
	    fiemap->fm_extents[0].fe_logical == 0)
		return 0;

	/* Find out stripe_no from ost_index saved in the fe_device */
	for (i = 0; i < lsm->lsm_stripe_count; i++) {
		struct lov_oinfo *oinfo = lsm->lsm_oinfo[i];

		if (lov_oinfo_is_dummy(oinfo))
			continue;

		if (oinfo->loi_ost_idx == fiemap->fm_extents[0].fe_device) {
			stripe_no = i;
			break;
		}
	}

	if (stripe_no == -1)
		return -EINVAL;

	/* If we have finished mapping on previous device, shift logical
	 * offset to start of next device */
	if (lov_stripe_intersects(lsm, stripe_no, fm_start, fm_end,
				  &lun_start, &lun_end) != 0 &&
	    local_end < lun_end) {
		fm_end_offset = local_end;
		*start_stripe = stripe_no;
	} else {
		/* This is a special value to indicate that caller should
		 * calculate offset in next stripe. */
		fm_end_offset = 0;
		*start_stripe = (stripe_no + 1) % lsm->lsm_stripe_count;
	}

	return fm_end_offset;
}

/**
 * Break down the FIEMAP request and send appropriate calls to individual OSTs.
 * This also handles the restarting of FIEMAP calls in case mapping overflows
 * the available number of extents in single call.
 *
 * \param env [in]		lustre environment
 * \param obj [in]		file object
 * \param fmkey [in]		fiemap request header and other info
 * \param fiemap [out]		fiemap buffer holding retrived map extents
 * \param buflen [in/out]	max buffer length of @fiemap, when iterate
 *				each OST, it is used to limit max map needed
 * \retval 0	success
 * \retval < 0	error
 */
static int lov_object_fiemap(const struct lu_env *env, struct cl_object *obj,
			     struct ll_fiemap_info_key *fmkey,
			     struct fiemap *fiemap, size_t *buflen)
{
	struct lov_stripe_md	*lsm;
	struct cl_object	*subobj = NULL;
	struct lov_obd		*lov = lu2lov_dev(obj->co_lu.lo_dev)->ld_lov;
	struct fiemap		*fm_local = NULL;
	struct ll_fiemap_extent	*lcl_fm_ext;
	loff_t			fm_start;
	loff_t			fm_end;
	loff_t			fm_length;
	loff_t			fm_end_offset;
	int			count_local;
	int			ost_index = 0;
	int			start_stripe;
	int			current_extent = 0;
	int			rc = 0;
	int			last_stripe;
	int			cur_stripe = 0;
	int			cur_stripe_wrap = 0;
	int			stripe_count;
	unsigned int		buffer_size = FIEMAP_BUFFER_SIZE;
	/* Whether have we collected enough extents */
	bool			enough = false;
	/* EOF for object */
	bool			ost_eof = false;
	/* done with required mapping for this OST? */
	bool			ost_done = false;
	ENTRY;

	lsm = lov_lsm_addref(cl2lov(obj));
	if (lsm == NULL)
		RETURN(-ENODATA);

	/**
	 * If the stripe_count > 1 and the application does not understand
	 * DEVICE_ORDER flag, it cannot interpret the extents correctly.
	 */
	if (lsm->lsm_stripe_count > 1 && !(fiemap->fm_flags &
					   FIEMAP_FLAG_DEVICE_ORDER))
		GOTO(out, rc = -ENOTSUPP);

	if (lsm_is_released(lsm)) {
		if (fiemap->fm_start < fmkey->oa.o_size) {
			/**
			 * released file, return a minimal FIEMAP if
			 * request fits in file-size.
			 */
			fiemap->fm_mapped_extents = 1;
			fiemap->fm_extents[0].fe_logical = fiemap->fm_start;
			if (fiemap->fm_start + fiemap->fm_length <
			    fmkey->oa.o_size)
				fiemap->fm_extents[0].fe_length =
					fiemap->fm_length;
			else
				fiemap->fm_extents[0].fe_length =
					fmkey->oa.o_size - fiemap->fm_start;
			fiemap->fm_extents[0].fe_flags |=
				FIEMAP_EXTENT_UNKNOWN | FIEMAP_EXTENT_LAST;
		}
		GOTO(out, rc = 0);
	}

	if (fiemap_count_to_size(fiemap->fm_extent_count) < buffer_size)
		buffer_size = fiemap_count_to_size(fiemap->fm_extent_count);

	OBD_ALLOC_LARGE(fm_local, buffer_size);
	if (fm_local == NULL)
		GOTO(out, rc = -ENOMEM);
	lcl_fm_ext = &fm_local->fm_extents[0];
	count_local = fiemap_size_to_count(buffer_size);

	fm_start = fiemap->fm_start;
	fm_length = fiemap->fm_length;
	/* Calculate start stripe, last stripe and length of mapping */
	start_stripe = lov_stripe_number(lsm, fm_start);
	fm_end = (fm_length == ~0ULL) ? fmkey->oa.o_size :
					fm_start + fm_length - 1;
	/* If fm_length != ~0ULL but fm_start_fm_length-1 exceeds file size */
	if (fm_end > fmkey->oa.o_size)
		fm_end = fmkey->oa.o_size;

	last_stripe = fiemap_calc_last_stripe(lsm, fm_start, fm_end,
					      start_stripe, &stripe_count);
	fm_end_offset = fiemap_calc_fm_end_offset(fiemap, lsm, fm_start, fm_end,
						  &start_stripe);
	if (fm_end_offset == -EINVAL)
		GOTO(out, rc = -EINVAL);

	/**
	 * Requested extent count exceeds the fiemap buffer size, shrink our
	 * ambition.
	 */
	if (fiemap_count_to_size(fiemap->fm_extent_count) > *buflen)
		fiemap->fm_extent_count = fiemap_size_to_count(*buflen);
	if (fiemap->fm_extent_count == 0)
		count_local = 0;

	/* Check each stripe */
	for (cur_stripe = start_stripe; stripe_count > 0;
	     --stripe_count,
	     cur_stripe = (cur_stripe + 1) % lsm->lsm_stripe_count) {
		loff_t req_fm_len; /* Stores length of required mapping */
		loff_t len_mapped_single_call;
		loff_t lun_start;
		loff_t lun_end;
		loff_t obd_object_end;
		unsigned int ext_count;

		cur_stripe_wrap = cur_stripe;

		/* Find out range of mapping on this stripe */
		if ((lov_stripe_intersects(lsm, cur_stripe, fm_start, fm_end,
					   &lun_start, &obd_object_end)) == 0)
			continue;

		if (lov_oinfo_is_dummy(lsm->lsm_oinfo[cur_stripe]))
			GOTO(out, rc = -EIO);

		/* If this is a continuation FIEMAP call and we are on
		 * starting stripe then lun_start needs to be set to
		 * fm_end_offset */
		if (fm_end_offset != 0 && cur_stripe == start_stripe)
			lun_start = fm_end_offset;

		if (fm_length != ~0ULL) {
			/* Handle fm_start + fm_length overflow */
			if (fm_start + fm_length < fm_start)
				fm_length = ~0ULL - fm_start;
			lun_end = lov_size_to_stripe(lsm, fm_start + fm_length,
						     cur_stripe);
		} else {
			lun_end = ~0ULL;
		}

		if (lun_start == lun_end)
			continue;

		req_fm_len = obd_object_end - lun_start;
		fm_local->fm_length = 0;
		len_mapped_single_call = 0;

		/* find lobsub object */
		subobj = lov_find_subobj(env, cl2lov(obj), lsm,
					     cur_stripe);
		if (IS_ERR(subobj))
			GOTO(out, rc = PTR_ERR(subobj));
		/* If the output buffer is very large and the objects have many
		 * extents we may need to loop on a single OST repeatedly */
		ost_eof = false;
		ost_done = false;
		do {
			if (fiemap->fm_extent_count > 0) {
				/* Don't get too many extents. */
				if (current_extent + count_local >
				    fiemap->fm_extent_count)
					count_local = fiemap->fm_extent_count -
						      current_extent;
			}

			lun_start += len_mapped_single_call;
			fm_local->fm_length = req_fm_len -
					      len_mapped_single_call;
			req_fm_len = fm_local->fm_length;
			fm_local->fm_extent_count = enough ? 1 : count_local;
			fm_local->fm_mapped_extents = 0;
			fm_local->fm_flags = fiemap->fm_flags;

			ost_index = lsm->lsm_oinfo[cur_stripe]->loi_ost_idx;

			if (ost_index < 0 ||
			    ost_index >= lov->desc.ld_tgt_count)
				GOTO(obj_put, rc = -EINVAL);
			/* If OST is inactive, return extent with UNKNOWN
			 * flag. */
			if (!lov->lov_tgts[ost_index]->ltd_active) {
				fm_local->fm_flags |= FIEMAP_EXTENT_LAST;
				fm_local->fm_mapped_extents = 1;

				lcl_fm_ext[0].fe_logical = lun_start;
				lcl_fm_ext[0].fe_length = obd_object_end -
							  lun_start;
				lcl_fm_ext[0].fe_flags |= FIEMAP_EXTENT_UNKNOWN;

				goto inactive_tgt;
			}

			fm_local->fm_start = lun_start;
			fm_local->fm_flags &= ~FIEMAP_FLAG_DEVICE_ORDER;
			memcpy(&fmkey->fiemap, fm_local, sizeof(*fm_local));
			*buflen = fiemap_count_to_size(
						fm_local->fm_extent_count);

			rc = cl_object_fiemap(env, subobj, fmkey, fm_local,
					      buflen);
			if (rc != 0)
				GOTO(obj_put, rc);
inactive_tgt:
			ext_count = fm_local->fm_mapped_extents;
			if (ext_count == 0) {
				ost_done = true;
				/* If last stripe has hold at the end,
				 * we need to return */
				if (cur_stripe_wrap == last_stripe) {
					fiemap->fm_mapped_extents = 0;
					goto finish;
				}
				break;
			} else if (enough) {
				/*
				 * We've collected enough extents and there are
				 * more extents after it.
				 */
				goto finish;
			}

			/* If we just need num of extents, got to next device */
			if (fiemap->fm_extent_count == 0) {
				current_extent += ext_count;
				break;
			}

			/* prepare to copy retrived map extents */
			len_mapped_single_call =
				lcl_fm_ext[ext_count - 1].fe_logical -
				lun_start + lcl_fm_ext[ext_count - 1].fe_length;

			/* Have we finished mapping on this device? */
			if (req_fm_len <= len_mapped_single_call)
				ost_done = true;

			/* Clear the EXTENT_LAST flag which can be present on
			 * the last extent */
			if (lcl_fm_ext[ext_count - 1].fe_flags &
			    FIEMAP_EXTENT_LAST)
				lcl_fm_ext[ext_count - 1].fe_flags &=
							~FIEMAP_EXTENT_LAST;
			if (lov_stripe_size(lsm,
					lcl_fm_ext[ext_count - 1].fe_logical +
					lcl_fm_ext[ext_count - 1].fe_length,
					cur_stripe) >= fmkey->oa.o_size)
				ost_eof = true;

			fiemap_prepare_and_copy_exts(fiemap, lcl_fm_ext,
						     ost_index, ext_count,
						     current_extent);
			current_extent += ext_count;

			/* Ran out of available extents? */
			if (current_extent >= fiemap->fm_extent_count)
				enough = true;
		} while (!ost_done && !ost_eof);

		cl_object_put(env, subobj);
		subobj = NULL;

		if (cur_stripe_wrap == last_stripe)
			goto finish;
	} /* for each stripe */
finish:
	/* Indicate that we are returning device offsets unless file just has
	 * single stripe */
	if (lsm->lsm_stripe_count > 1)
		fiemap->fm_flags |= FIEMAP_FLAG_DEVICE_ORDER;

	if (fiemap->fm_extent_count == 0)
		goto skip_last_device_calc;

	/* Check if we have reached the last stripe and whether mapping for that
	 * stripe is done. */
	if ((cur_stripe_wrap == last_stripe) && (ost_done || ost_eof))
		fiemap->fm_extents[current_extent - 1].fe_flags |=
							     FIEMAP_EXTENT_LAST;
skip_last_device_calc:
	fiemap->fm_mapped_extents = current_extent;
obj_put:
	if (subobj != NULL)
		cl_object_put(env, subobj);
out:
	if (fm_local != NULL)
		OBD_FREE_LARGE(fm_local, buffer_size);
	lov_lsm_put(obj, lsm);
	RETURN(rc);
}

static int lov_dispatch_obd_info_get(const struct lu_env *env,
				     struct cl_object *obj,
				     struct obd_info *oinfo,
				     struct ptlrpc_request_set *set)
{
	struct cl_object	*subobj = NULL;
	struct lov_obd		*lov = lu2lov_dev(obj->co_lu.lo_dev)->ld_lov;
	struct lov_request_set	*lovset;
	struct list_head	*pos;
	struct lov_request	*req;
	int			rc;
	int			rc2;
	ENTRY;

	rc = lov_prep_getattr_set(lov2obd(lov)->obd_self_export, oinfo,
				  &lovset);
	if (rc != 0)
		RETURN(rc);

	CDEBUG(D_INFO, "objid "DOSTID": %ux%u byte stripes.\n",
	       POSTID(&oinfo->oi_md->lsm_oi),
	       oinfo->oi_md->lsm_stripe_count,
	       oinfo->oi_md->lsm_stripe_size);

	list_for_each(pos, &lovset->set_list) {
		req = list_entry(pos, struct lov_request, rq_link);

		CDEBUG(D_INFO, "objid "DOSTID"[%d] has subobj "DOSTID" at idx"
		       "%u\n", POSTID(&oinfo->oi_oa->o_oi), req->rq_stripe,
		       POSTID(&req->rq_oi.oi_oa->o_oi), req->rq_idx);
		subobj = lov_find_subobj(env, cl2lov(obj), oinfo->oi_md,
					 req->rq_stripe);
		if (IS_ERR(subobj))
			GOTO(errout, rc = PTR_ERR(subobj));

		rc = cl_object_obd_info_get(env, subobj, &req->rq_oi, set);
		cl_object_put(env, subobj);
		if (rc != 0) {
			CERROR("%s: getattr objid "DOSTID" subobj"
			       DOSTID" on OST idx %d: rc = %d\n",
			       lov2obd(lov)->obd_name,
			       POSTID(&oinfo->oi_oa->o_oi),
			       POSTID(&req->rq_oi.oi_oa->o_oi),
			       req->rq_idx, rc);
			GOTO(errout, rc);
		}
	}

	if (!list_empty(&set->set_requests)) {
		LASSERT(rc == 0);
		LASSERT(set->set_interpret == NULL);
		set->set_interpret = lov_getattr_interpret;
		set->set_arg = lovset;
		GOTO(out, rc);
	}
errout:
	if (rc)
		atomic_set(&lovset->set_completes, 0);
	rc2 = lov_fini_getattr_set(lovset);
	rc = rc != 0 ? rc : rc2;
out:
	RETURN(rc);
}

static int lov_object_data_version(const struct lu_env *env,
				   struct cl_object *obj, __u64 *data_version,
				   int flags)
{
	struct ptlrpc_request_set	*set;
	struct obd_info			oinfo =  { { { 0 } } };
	struct obdo			*obdo = NULL;
	struct lov_stripe_md		*lsm;
	int				rc;
	ENTRY;

	lsm = lov_lsm_addref(cl2lov(obj));
	if (!lsm_has_objects(lsm)) {
		/* If no stripe, we consider version is 0. */
		*data_version = 0;
		GOTO(out, rc = 0);
	}

	OBD_ALLOC_PTR(obdo);
	if (obdo == NULL)
		GOTO(out, rc = -ENOMEM);

	oinfo.oi_md = lsm;
	oinfo.oi_oa = obdo;
	obdo->o_oi = lsm->lsm_oi;
	obdo->o_mode = S_IFREG;
	obdo->o_valid = OBD_MD_FLID | OBD_MD_FLGROUP | OBD_MD_FLTYPE;
	if (flags & (LL_DV_RD_FLUSH | LL_DV_WR_FLUSH)) {
		obdo->o_valid |= OBD_MD_FLFLAGS;
		obdo->o_flags |= OBD_FL_SRVLOCK;
		if (flags & LL_DV_WR_FLUSH)
			obdo->o_flags |= OBD_FL_FLUSH;
	}

	set = ptlrpc_prep_set();
	if (set == NULL)
		GOTO(out_obdo, rc = -ENOMEM);

	rc = lov_dispatch_obd_info_get(env, obj, &oinfo, set);
	if (rc == 0)
		rc = ptlrpc_set_wait(set);
	ptlrpc_set_destroy(set);
	if (rc == 0) {
		oinfo.oi_oa->o_valid &= OBD_MD_FLDATAVERSION | OBD_MD_FLFLAGS;
		if (flags & LL_DV_WR_FLUSH &&
		    !(oinfo.oi_oa->o_valid & OBD_MD_FLFLAGS &&
		      oinfo.oi_oa->o_flags & OBD_FL_FLUSH))
			rc = -EOPNOTSUPP;
		else if (!(obdo->o_valid & OBD_MD_FLDATAVERSION))
			rc = -EOPNOTSUPP;
		else
			*data_version = obdo->o_data_version;
	}
out_obdo:
	OBD_FREE_PTR(obdo);
out:
	lov_lsm_put(obj, lsm);
	RETURN(rc);
}

static int lov_object_getstripe(const struct lu_env *env, struct cl_object *obj,
				struct lov_user_md __user *lum)
{
	struct lov_object	*lov = cl2lov(obj);
	struct lov_stripe_md	*lsm;
	int			rc = 0;
	ENTRY;

	lsm = lov_lsm_addref(lov);
	if (lsm == NULL)
		RETURN(-ENODATA);

	rc = lov_getstripe(cl2lov(obj), lsm, lum);
	lov_lsm_put(obj, lsm);
	RETURN(rc);
}

static int lov_object_find_cbdata(const struct lu_env *env,
				  struct cl_object *obj, ldlm_iterator_t iter,
				  void *data)
{
	int rc;
	ENTRY;

	/* call cl_object_find_cbdata for sub obj */
	rc = LOV_2DISPATCH_NOLOCK(cl2lov(obj), llo_find_cbdata,
				  env, obj, iter, data);
	RETURN(rc);
}

static const struct cl_object_operations lov_ops = {
	.coo_page_init    = lov_page_init,
	.coo_lock_init    = lov_lock_init,
	.coo_io_init      = lov_io_init,
	.coo_attr_get     = lov_attr_get,
	.coo_attr_update  = lov_attr_update,
	.coo_conf_set     = lov_conf_set,
	.coo_getstripe    = lov_object_getstripe,
	.coo_find_cbdata  = lov_object_find_cbdata,
	.coo_fiemap       = lov_object_fiemap,
	.coo_data_version = lov_object_data_version,
};

static const struct lu_object_operations lov_lu_obj_ops = {
        .loo_object_init      = lov_object_init,
        .loo_object_delete    = lov_object_delete,
        .loo_object_release   = NULL,
        .loo_object_free      = lov_object_free,
        .loo_object_print     = lov_object_print,
        .loo_object_invariant = NULL
};

struct lu_object *lov_object_alloc(const struct lu_env *env,
				   const struct lu_object_header *unused,
				   struct lu_device *dev)
{
	struct lov_object *lov;
	struct lu_object  *obj;

	ENTRY;
	OBD_SLAB_ALLOC_PTR_GFP(lov, lov_object_kmem, GFP_NOFS);
	if (lov != NULL) {
		obj = lov2lu(lov);
		lu_object_init(obj, NULL, dev);
		lov->lo_cl.co_ops = &lov_ops;
		lov->lo_type = -1; /* invalid, to catch uninitialized type */
		/*
		 * object io operation vector (cl_object::co_iop) is installed
		 * later in lov_object_init(), as different vectors are used
		 * for object with different layouts.
		 */
		obj->lo_ops = &lov_lu_obj_ops;
	} else
		obj = NULL;
	RETURN(obj);
}

struct lov_stripe_md *lov_lsm_addref(struct lov_object *lov)
{
	struct lov_stripe_md *lsm = NULL;

	lov_conf_freeze(lov);
	if (lov->lo_lsm != NULL) {
		lsm = lsm_addref(lov->lo_lsm);
		CDEBUG(D_INODE, "lsm %p addref %d/%d by %p.\n",
			lsm, atomic_read(&lsm->lsm_refc),
			lov->lo_layout_invalid, current);
	}
	lov_conf_thaw(lov);
	return lsm;
}

int lov_read_and_clear_async_rc(struct cl_object *clob)
{
	struct lu_object *luobj;
	int rc = 0;
	ENTRY;

	luobj = lu_object_locate(&cl_object_header(clob)->coh_lu,
				 &lov_device_type);
	if (luobj != NULL) {
		struct lov_object *lov = lu2lov(luobj);

		lov_conf_freeze(lov);
		switch (lov->lo_type) {
		case LLT_RAID0: {
			struct lov_stripe_md *lsm;
			int i;

			lsm = lov->lo_lsm;
			LASSERT(lsm != NULL);
			for (i = 0; i < lsm->lsm_stripe_count; i++) {
				struct lov_oinfo *loi = lsm->lsm_oinfo[i];

				if (lov_oinfo_is_dummy(loi))
					continue;

				if (loi->loi_ar.ar_rc && !rc)
					rc = loi->loi_ar.ar_rc;
				loi->loi_ar.ar_rc = 0;
			}
		}
		case LLT_RELEASED:
		case LLT_EMPTY:
			break;
		default:
			LBUG();
		}
		lov_conf_thaw(lov);
	}
	RETURN(rc);
}
EXPORT_SYMBOL(lov_read_and_clear_async_rc);

/** @} lov */