/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2016, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/obdclass/dt_object.c
 *
 * Dt Object.
 * Generic functions from dt_object.h
 *
 * Author: Nikita Danilov <nikita@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_CLASS

#include <linux/list.h>
#include <obd.h>
#include <dt_object.h>
/* fid_be_to_cpu() */
#include <lustre_fid.h>
#include <lustre_nodemap.h>
#include <lustre_quota.h>

/* context key constructor/destructor: dt_global_key_init, dt_global_key_fini */
LU_KEY_INIT(dt_global, struct dt_thread_info);
LU_KEY_FINI(dt_global, struct dt_thread_info);

struct lu_context_key dt_key = {
        .lct_tags = LCT_MD_THREAD | LCT_DT_THREAD | LCT_MG_THREAD | LCT_LOCAL,
        .lct_init = dt_global_key_init,
        .lct_fini = dt_global_key_fini
};

/* no lock is necessary to protect the list, because call-backs
 * are added during system startup. Please refer to "struct dt_device".
 */
void dt_txn_callback_add(struct dt_device *dev, struct dt_txn_callback *cb)
{
	list_add(&cb->dtc_linkage, &dev->dd_txn_callbacks);
}
EXPORT_SYMBOL(dt_txn_callback_add);

void dt_txn_callback_del(struct dt_device *dev, struct dt_txn_callback *cb)
{
	list_del_init(&cb->dtc_linkage);
}
EXPORT_SYMBOL(dt_txn_callback_del);

int dt_txn_hook_start(const struct lu_env *env,
                      struct dt_device *dev, struct thandle *th)
{
	int rc = 0;
	struct dt_txn_callback *cb;

	if (th->th_local)
		return 0;

	list_for_each_entry(cb, &dev->dd_txn_callbacks, dtc_linkage) {
		struct thandle *dtc_th = th;

		if (cb->dtc_txn_start == NULL ||
		    !(cb->dtc_tag & env->le_ctx.lc_tags))
			continue;

		/* Usually dt_txn_hook_start is called from bottom device,
		 * and if the thandle has th_top, then we need use top
		 * thandle for the callback in the top thandle layer */
		if (th->th_top != NULL)
			dtc_th = th->th_top;

		rc = cb->dtc_txn_start(env, dtc_th, cb->dtc_cookie);
		if (rc < 0)
			break;
	}
	return rc;
}
EXPORT_SYMBOL(dt_txn_hook_start);

int dt_txn_hook_stop(const struct lu_env *env, struct thandle *th)
{
	struct dt_device       *dev = th->th_dev;
	struct dt_txn_callback *cb;
	int                     rc = 0;

	if (th->th_local)
		return 0;

	if (OBD_FAIL_CHECK(OBD_FAIL_DT_TXN_STOP))
		return -EIO;

	list_for_each_entry(cb, &dev->dd_txn_callbacks, dtc_linkage) {
		struct thandle *dtc_th = th;

		if (cb->dtc_txn_stop == NULL ||
		    !(cb->dtc_tag & env->le_ctx.lc_tags))
			continue;

		/* Usually dt_txn_hook_stop is called from bottom device,
		 * and if the thandle has th_top, then we need use top
		 * thandle for the callback in the top thandle layer */
		if (th->th_top != NULL)
			dtc_th = th->th_top;

		rc = cb->dtc_txn_stop(env, dtc_th, cb->dtc_cookie);
		if (rc < 0)
			break;
	}
	return rc;
}
EXPORT_SYMBOL(dt_txn_hook_stop);

void dt_txn_hook_commit(struct thandle *th)
{
	struct dt_txn_callback *cb;

	if (th->th_local)
		return;

	list_for_each_entry(cb, &th->th_dev->dd_txn_callbacks,
			    dtc_linkage) {
		/* Right now, the bottom device (OSD) will use this hook
		 * commit to notify OSP, so we do not check and replace
		 * the thandle to top thandle now */
		if (cb->dtc_txn_commit)
			cb->dtc_txn_commit(th, cb->dtc_cookie);
	}
}
EXPORT_SYMBOL(dt_txn_hook_commit);

int dt_device_init(struct dt_device *dev, struct lu_device_type *t)
{
	INIT_LIST_HEAD(&dev->dd_txn_callbacks);
	return lu_device_init(&dev->dd_lu_dev, t);
}
EXPORT_SYMBOL(dt_device_init);

void dt_device_fini(struct dt_device *dev)
{
        lu_device_fini(&dev->dd_lu_dev);
}
EXPORT_SYMBOL(dt_device_fini);

int dt_object_init(struct dt_object *obj,
                   struct lu_object_header *h, struct lu_device *d)

{
        return lu_object_init(&obj->do_lu, h, d);
}
EXPORT_SYMBOL(dt_object_init);

void dt_object_fini(struct dt_object *obj)
{
        lu_object_fini(&obj->do_lu);
}
EXPORT_SYMBOL(dt_object_fini);

int dt_try_as_dir(const struct lu_env *env, struct dt_object *obj)
{
        if (obj->do_index_ops == NULL)
                obj->do_ops->do_index_try(env, obj, &dt_directory_features);
        return obj->do_index_ops != NULL;
}
EXPORT_SYMBOL(dt_try_as_dir);

enum dt_format_type dt_mode_to_dft(__u32 mode)
{
        enum dt_format_type result;

        switch (mode & S_IFMT) {
        case S_IFDIR:
                result = DFT_DIR;
                break;
        case S_IFREG:
                result = DFT_REGULAR;
                break;
        case S_IFLNK:
                result = DFT_SYM;
                break;
        case S_IFCHR:
        case S_IFBLK:
        case S_IFIFO:
        case S_IFSOCK:
                result = DFT_NODE;
                break;
        default:
                LBUG();
                break;
        }
        return result;
}
EXPORT_SYMBOL(dt_mode_to_dft);

/**
 * lookup fid for object named \a name in directory \a dir.
 */

int dt_lookup_dir(const struct lu_env *env, struct dt_object *dir,
                  const char *name, struct lu_fid *fid)
{
	if (dt_try_as_dir(env, dir))
		return dt_lookup(env, dir, (struct dt_rec *)fid,
				 (const struct dt_key *)name);
	return -ENOTDIR;
}
EXPORT_SYMBOL(dt_lookup_dir);

/* this differs from dt_locate by top_dev as parameter
 * but not one from lu_site */
struct dt_object *dt_locate_at(const struct lu_env *env,
			       struct dt_device *dev,
			       const struct lu_fid *fid,
			       struct lu_device *top_dev,
			       const struct lu_object_conf *conf)
{
	struct lu_object *lo;
	struct lu_object *n;

	lo = lu_object_find_at(env, top_dev, fid, conf);
	if (IS_ERR(lo))
		return ERR_PTR(PTR_ERR(lo));

	LASSERT(lo != NULL);

	list_for_each_entry(n, &lo->lo_header->loh_layers, lo_linkage) {
		if (n->lo_dev == &dev->dd_lu_dev)
			return container_of0(n, struct dt_object, do_lu);
	}

	return ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL(dt_locate_at);

/**
 * find an object named \a entry in given \a dfh->dfh_o directory.
 */
static int dt_find_entry(const struct lu_env *env, const char *entry, void *data)
{
        struct dt_find_hint  *dfh = data;
        struct dt_device     *dt = dfh->dfh_dt;
        struct lu_fid        *fid = dfh->dfh_fid;
        struct dt_object     *obj = dfh->dfh_o;
        int                   result;

        result = dt_lookup_dir(env, obj, entry, fid);
        lu_object_put(env, &obj->do_lu);
        if (result == 0) {
                obj = dt_locate(env, dt, fid);
                if (IS_ERR(obj))
                        result = PTR_ERR(obj);
        }
        dfh->dfh_o = obj;
        return result;
}

/**
 * Abstract function which parses path name. This function feeds
 * path component to \a entry_func.
 */
int dt_path_parser(const struct lu_env *env,
                   char *path, dt_entry_func_t entry_func,
                   void *data)
{
        char *e;
        int rc = 0;

        while (1) {
                e = strsep(&path, "/");
                if (e == NULL)
                        break;

                if (e[0] == 0) {
                        if (!path || path[0] == '\0')
                                break;
                        continue;
                }
                rc = entry_func(env, e, data);
                if (rc)
                        break;
        }

        return rc;
}

struct dt_object *
dt_store_resolve(const struct lu_env *env, struct dt_device *dt,
		 const char *path, struct lu_fid *fid)
{
	struct dt_thread_info *info = dt_info(env);
	struct dt_find_hint   *dfh = &info->dti_dfh;
	struct dt_object      *obj;
	int		       result;


        dfh->dfh_dt = dt;
        dfh->dfh_fid = fid;

	strlcpy(info->dti_buf, path, sizeof(info->dti_buf));

        result = dt->dd_ops->dt_root_get(env, dt, fid);
        if (result == 0) {
                obj = dt_locate(env, dt, fid);
                if (!IS_ERR(obj)) {
                        dfh->dfh_o = obj;
			result = dt_path_parser(env, info->dti_buf,
						dt_find_entry, dfh);
                        if (result != 0)
                                obj = ERR_PTR(result);
                        else
                                obj = dfh->dfh_o;
                }
        } else {
                obj = ERR_PTR(result);
        }
        return obj;
}

static struct dt_object *dt_reg_open(const struct lu_env *env,
                                     struct dt_device *dt,
                                     struct dt_object *p,
                                     const char *name,
                                     struct lu_fid *fid)
{
        struct dt_object *o;
        int result;

        result = dt_lookup_dir(env, p, name, fid);
        if (result == 0){
                o = dt_locate(env, dt, fid);
        }
        else
                o = ERR_PTR(result);

        return o;
}

/**
 * Open dt object named \a filename from \a dirname directory.
 *      \param  dt      dt device
 *      \param  fid     on success, object fid is stored in *fid
 */
struct dt_object *dt_store_open(const struct lu_env *env,
                                struct dt_device *dt,
                                const char *dirname,
                                const char *filename,
                                struct lu_fid *fid)
{
        struct dt_object *file;
        struct dt_object *dir;

        dir = dt_store_resolve(env, dt, dirname, fid);
        if (!IS_ERR(dir)) {
                file = dt_reg_open(env, dt, dir,
                                   filename, fid);
                lu_object_put(env, &dir->do_lu);
        } else {
                file = dir;
        }
        return file;
}

struct dt_object *dt_find_or_create(const struct lu_env *env,
                                    struct dt_device *dt,
                                    const struct lu_fid *fid,
                                    struct dt_object_format *dof,
                                    struct lu_attr *at)
{
        struct dt_object *dto;
        struct thandle *th;
        int rc;

        ENTRY;

        dto = dt_locate(env, dt, fid);
        if (IS_ERR(dto))
                RETURN(dto);

        LASSERT(dto != NULL);
        if (dt_object_exists(dto))
                RETURN(dto);

        th = dt_trans_create(env, dt);
        if (IS_ERR(th))
                GOTO(out, rc = PTR_ERR(th));

        rc = dt_declare_create(env, dto, at, NULL, dof, th);
        if (rc)
                GOTO(trans_stop, rc);

        rc = dt_trans_start_local(env, dt, th);
        if (rc)
                GOTO(trans_stop, rc);

        dt_write_lock(env, dto, 0);
        if (dt_object_exists(dto))
                GOTO(unlock, rc = 0);

        CDEBUG(D_OTHER, "create new object "DFID"\n", PFID(fid));

        rc = dt_create(env, dto, at, NULL, dof, th);
        if (rc)
                GOTO(unlock, rc);
        LASSERT(dt_object_exists(dto));
unlock:
        dt_write_unlock(env, dto);
trans_stop:
        dt_trans_stop(env, dt, th);
out:
        if (rc) {
                lu_object_put(env, &dto->do_lu);
                RETURN(ERR_PTR(rc));
        }
        RETURN(dto);
}
EXPORT_SYMBOL(dt_find_or_create);

/* dt class init function. */
int dt_global_init(void)
{
        int result;

        LU_CONTEXT_KEY_INIT(&dt_key);
        result = lu_context_key_register(&dt_key);
        return result;
}

void dt_global_fini(void)
{
        lu_context_key_degister(&dt_key);
}

/**
 * Generic read helper. May return an error for partial reads.
 *
 * \param env  lustre environment
 * \param dt   object to be read
 * \param buf  lu_buf to be filled, with buffer pointer and length
 * \param pos position to start reading, updated as data is read
 *
 * \retval real size of data read
 * \retval -ve errno on failure
 */
int dt_read(const struct lu_env *env, struct dt_object *dt,
            struct lu_buf *buf, loff_t *pos)
{
	LASSERTF(dt != NULL, "dt is NULL when we want to read record\n");
	return dt->do_body_ops->dbo_read(env, dt, buf, pos);
}
EXPORT_SYMBOL(dt_read);

/**
 * Read structures of fixed size from storage.  Unlike dt_read(), using
 * dt_record_read() will return an error for partial reads.
 *
 * \param env  lustre environment
 * \param dt   object to be read
 * \param buf  lu_buf to be filled, with buffer pointer and length
 * \param pos position to start reading, updated as data is read
 *
 * \retval 0 on successfully reading full buffer
 * \retval -EFAULT on short read
 * \retval -ve errno on failure
 */
int dt_record_read(const struct lu_env *env, struct dt_object *dt,
                   struct lu_buf *buf, loff_t *pos)
{
	ssize_t size;

	LASSERTF(dt != NULL, "dt is NULL when we want to read record\n");

	size = dt->do_body_ops->dbo_read(env, dt, buf, pos);
	if (size < 0)
		return size;
	return (size == (ssize_t)buf->lb_len) ? 0 : -EFAULT;
}
EXPORT_SYMBOL(dt_record_read);

int dt_record_write(const struct lu_env *env, struct dt_object *dt,
                    const struct lu_buf *buf, loff_t *pos, struct thandle *th)
{
	ssize_t size;

	LASSERTF(dt != NULL, "dt is NULL when we want to write record\n");
	LASSERT(th != NULL);
	LASSERT(dt->do_body_ops);
	LASSERT(dt->do_body_ops->dbo_write);

	size = dt->do_body_ops->dbo_write(env, dt, buf, pos, th, 1);
	if (size < 0)
		return size;
	return (size == (ssize_t)buf->lb_len) ? 0 : -EFAULT;
}
EXPORT_SYMBOL(dt_record_write);

int dt_declare_version_set(const struct lu_env *env, struct dt_object *o,
                           struct thandle *th)
{
        struct lu_buf vbuf;
        char *xname = XATTR_NAME_VERSION;

        LASSERT(o);
        vbuf.lb_buf = NULL;
        vbuf.lb_len = sizeof(dt_obj_version_t);
        return dt_declare_xattr_set(env, o, &vbuf, xname, 0, th);

}
EXPORT_SYMBOL(dt_declare_version_set);

void dt_version_set(const struct lu_env *env, struct dt_object *o,
                    dt_obj_version_t version, struct thandle *th)
{
        struct lu_buf vbuf;
        char *xname = XATTR_NAME_VERSION;
        int rc;

        LASSERT(o);
        vbuf.lb_buf = &version;
        vbuf.lb_len = sizeof(version);

	rc = dt_xattr_set(env, o, &vbuf, xname, 0, th);
        if (rc < 0)
                CDEBUG(D_INODE, "Can't set version, rc %d\n", rc);
        return;
}
EXPORT_SYMBOL(dt_version_set);

dt_obj_version_t dt_version_get(const struct lu_env *env, struct dt_object *o)
{
        struct lu_buf vbuf;
        char *xname = XATTR_NAME_VERSION;
        dt_obj_version_t version;
        int rc;

        LASSERT(o);
        vbuf.lb_buf = &version;
        vbuf.lb_len = sizeof(version);
	rc = dt_xattr_get(env, o, &vbuf, xname);
        if (rc != sizeof(version)) {
                CDEBUG(D_INODE, "Can't get version, rc %d\n", rc);
                version = 0;
        }
        return version;
}
EXPORT_SYMBOL(dt_version_get);

/* list of all supported index types */

/* directories */
const struct dt_index_features dt_directory_features;
EXPORT_SYMBOL(dt_directory_features);

/* scrub iterator */
const struct dt_index_features dt_otable_features;
EXPORT_SYMBOL(dt_otable_features);

/* lfsck layout orphan */
const struct dt_index_features dt_lfsck_layout_orphan_features = {
	.dif_flags		= 0,
	.dif_keysize_min	= sizeof(struct lu_fid),
	.dif_keysize_max	= sizeof(struct lu_fid),
	.dif_recsize_min	= sizeof(struct lu_orphan_rec),
	.dif_recsize_max	= sizeof(struct lu_orphan_rec),
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_lfsck_layout_orphan_features);

/* lfsck layout dangling */
const struct dt_index_features dt_lfsck_layout_dangling_features = {
	.dif_flags		= DT_IND_UPDATE,
	.dif_keysize_min	= sizeof(struct lu_fid),
	.dif_keysize_max	= sizeof(struct lu_fid),
	.dif_recsize_min	= sizeof(struct lu_fid),
	.dif_recsize_max	= sizeof(struct lu_fid),
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_lfsck_layout_dangling_features);

/* lfsck namespace */
const struct dt_index_features dt_lfsck_namespace_features = {
	.dif_flags		= DT_IND_UPDATE,
	.dif_keysize_min	= sizeof(struct lu_fid),
	.dif_keysize_max	= sizeof(struct lu_fid),
	.dif_recsize_min	= sizeof(__u8),
	.dif_recsize_max	= sizeof(__u8),
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_lfsck_namespace_features);

/* accounting indexes */
const struct dt_index_features dt_acct_features = {
	.dif_flags		= DT_IND_UPDATE,
	.dif_keysize_min	= sizeof(__u64), /* 64-bit uid/gid */
	.dif_keysize_max	= sizeof(__u64), /* 64-bit uid/gid */
	.dif_recsize_min	= sizeof(struct lquota_acct_rec), /* 16 bytes */
	.dif_recsize_max	= sizeof(struct lquota_acct_rec), /* 16 bytes */
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_acct_features);

/* global quota files */
const struct dt_index_features dt_quota_glb_features = {
	.dif_flags		= DT_IND_UPDATE,
	/* a different key would have to be used for per-directory quota */
	.dif_keysize_min	= sizeof(__u64), /* 64-bit uid/gid */
	.dif_keysize_max	= sizeof(__u64), /* 64-bit uid/gid */
	.dif_recsize_min	= sizeof(struct lquota_glb_rec), /* 32 bytes */
	.dif_recsize_max	= sizeof(struct lquota_glb_rec), /* 32 bytes */
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_quota_glb_features);

/* slave quota files */
const struct dt_index_features dt_quota_slv_features = {
	.dif_flags		= DT_IND_UPDATE,
	/* a different key would have to be used for per-directory quota */
	.dif_keysize_min	= sizeof(__u64), /* 64-bit uid/gid */
	.dif_keysize_max	= sizeof(__u64), /* 64-bit uid/gid */
	.dif_recsize_min	= sizeof(struct lquota_slv_rec), /* 8 bytes */
	.dif_recsize_max	= sizeof(struct lquota_slv_rec), /* 8 bytes */
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_quota_slv_features);

/* nodemap files, nodemap_rec size asserted in nodemap_storage.c */
const struct dt_index_features dt_nodemap_features = {
	.dif_flags		= DT_IND_UPDATE,
	.dif_keysize_min	= sizeof(__u64), /* 64-bit nodemap/record id */
	.dif_keysize_max	= sizeof(__u64), /* 64-bit nodemap/record id */
	.dif_recsize_min	= sizeof(union nodemap_rec), /* 32 bytes */
	.dif_recsize_max	= sizeof(union nodemap_rec), /* 32 bytes */
	.dif_ptrsize		= 4
};
EXPORT_SYMBOL(dt_nodemap_features);

/* helper function returning what dt_index_features structure should be used
 * based on the FID sequence. This is used by OBD_IDX_READ RPC */
static inline const struct dt_index_features *dt_index_feat_select(__u64 seq,
								   __u32 mode)
{
	if (seq == FID_SEQ_QUOTA_GLB) {
		/* global quota index */
		if (!S_ISREG(mode))
			/* global quota index should be a regular file */
			return ERR_PTR(-ENOENT);
		return &dt_quota_glb_features;
	} else if (seq == FID_SEQ_QUOTA) {
		/* quota slave index */
		if (!S_ISREG(mode))
			/* slave index should be a regular file */
			return ERR_PTR(-ENOENT);
		return &dt_quota_slv_features;
	} else if (seq == FID_SEQ_LAYOUT_RBTREE){
		return &dt_lfsck_layout_orphan_features;
	} else if (seq >= FID_SEQ_NORMAL) {
		/* object is part of the namespace, verify that it is a
		 * directory */
		if (!S_ISDIR(mode))
			/* sorry, we can only deal with directory */
			return ERR_PTR(-ENOTDIR);
		return &dt_directory_features;
	}

	return ERR_PTR(-EOPNOTSUPP);
}

/*
 * Fill a lu_idxpage with key/record pairs read for transfer via OBD_IDX_READ
 * RPC
 *
 * \param env - is the environment passed by the caller
 * \param lp  - is a pointer to the lu_page to fill
 * \param nob - is the maximum number of bytes that should be copied
 * \param iops - is the index operation vector associated with the index object
 * \param it   - is a pointer to the current iterator
 * \param attr - is the index attribute to pass to iops->rec()
 * \param arg  - is a pointer to the idx_info structure
 */
static int dt_index_page_build(const struct lu_env *env, union lu_page *lp,
			       size_t nob, const struct dt_it_ops *iops,
			       struct dt_it *it, __u32 attr, void *arg)
{
	struct idx_info		*ii = (struct idx_info *)arg;
	struct lu_idxpage	*lip = &lp->lp_idx;
	char			*entry;
	size_t			 size;
	int			 rc;
	ENTRY;

	if (nob < LIP_HDR_SIZE)
		return -EINVAL;

	/* initialize the header of the new container */
	memset(lip, 0, LIP_HDR_SIZE);
	lip->lip_magic = LIP_MAGIC;
	nob           -= LIP_HDR_SIZE;

	/* compute size needed to store a key/record pair */
	size = ii->ii_recsize + ii->ii_keysize;
	if ((ii->ii_flags & II_FL_NOHASH) == 0)
		/* add hash if the client wants it */
		size += sizeof(__u64);

	entry = lip->lip_entries;
	do {
		char		*tmp_entry = entry;
		struct dt_key	*key;
		__u64		hash;
		__u16		keysize;
		__u16		recsize;

		/* fetch 64-bit hash value */
		hash = iops->store(env, it);
		ii->ii_hash_end = hash;

		if (OBD_FAIL_CHECK(OBD_FAIL_OBD_IDX_READ_BREAK)) {
			if (lip->lip_nr != 0)
				GOTO(out, rc = 0);
		}

		if (nob < size) {
			if (lip->lip_nr == 0)
				GOTO(out, rc = -EINVAL);
			GOTO(out, rc = 0);
		}

		if (!(ii->ii_flags & II_FL_NOHASH)) {
			/* client wants to the 64-bit hash value associated with
			 * each record */
			memcpy(tmp_entry, &hash, sizeof(hash));
			tmp_entry += sizeof(hash);
		}

		if (ii->ii_flags & II_FL_VARKEY)
			keysize = iops->key_size(env, it);
		else
			keysize = ii->ii_keysize;

		if (!(ii->ii_flags & II_FL_NOKEY)) {
			/* then the key value */
			key = iops->key(env, it);
			memcpy(tmp_entry, key, keysize);
			tmp_entry += keysize;
		}

		/* and finally the record */
		rc = iops->rec(env, it, (struct dt_rec *)tmp_entry, attr);
		if (rc != -ESTALE) {
			if (rc != 0)
				GOTO(out, rc);

			/* hash/key/record successfully copied! */
			lip->lip_nr++;
			if (unlikely(lip->lip_nr == 1 && ii->ii_count == 0))
				ii->ii_hash_start = hash;

			if (ii->ii_flags & II_FL_VARREC)
				recsize = iops->rec_size(env, it, attr);
			else
				recsize = ii->ii_recsize;

			entry = tmp_entry + recsize;
			nob -= size;
		}

		/* move on to the next record */
		do {
			rc = iops->next(env, it);
		} while (rc == -ESTALE);

	} while (rc == 0);

	GOTO(out, rc);
out:
	if (rc >= 0 && lip->lip_nr > 0)
		/* one more container */
		ii->ii_count++;
	if (rc > 0)
		/* no more entries */
		ii->ii_hash_end = II_END_OFF;
	return rc;
}


/*
 * Walk index and fill lu_page containers with key/record pairs
 *
 * \param env - is the environment passed by the caller
 * \param obj - is the index object to parse
 * \param rdpg - is the lu_rdpg descriptor associated with the transfer
 * \param filler - is the callback function responsible for filling a lu_page
 *                 with key/record pairs in the format wanted by the caller.
 *                 If NULL, uses dt_index_page_build
 * \param arg    - is an opaq argument passed to the filler function
 *
 * \retval sum (in bytes) of all filled lu_pages
 * \retval -ve errno on failure
 */
int dt_index_walk(const struct lu_env *env, struct dt_object *obj,
		  const struct lu_rdpg *rdpg, dt_index_page_build_t filler,
		  void *arg)
{
	struct dt_it		*it;
	const struct dt_it_ops	*iops;
	size_t			 pageidx, nob, nlupgs = 0;
	int			 rc;
	ENTRY;

	LASSERT(rdpg->rp_pages != NULL);
	LASSERT(obj->do_index_ops != NULL);

	if (filler == NULL)
		filler = dt_index_page_build;

	nob = rdpg->rp_count;
	if (nob == 0)
		RETURN(-EFAULT);

	/* Iterate through index and fill containers from @rdpg */
	iops = &obj->do_index_ops->dio_it;
	LASSERT(iops != NULL);
	it = iops->init(env, obj, rdpg->rp_attrs);
	if (IS_ERR(it))
		RETURN(PTR_ERR(it));

	rc = iops->load(env, it, rdpg->rp_hash);
	if (rc == 0) {
		/*
		 * Iterator didn't find record with exactly the key requested.
		 *
		 * It is currently either
		 *
		 *     - positioned above record with key less than
		 *     requested---skip it.
		 *     - or not positioned at all (is in IAM_IT_SKEWED
		 *     state)---position it on the next item.
		 */
		rc = iops->next(env, it);
	} else if (rc > 0) {
		rc = 0;
	} else {
		if (rc == -ENODATA)
			rc = 0;
		GOTO(out, rc);
	}

	/* Fill containers one after the other. There might be multiple
	 * containers per physical page.
	 *
	 * At this point and across for-loop:
	 *  rc == 0 -> ok, proceed.
	 *  rc >  0 -> end of index.
	 *  rc <  0 -> error. */
	for (pageidx = 0; rc == 0 && nob > 0; pageidx++) {
		union lu_page	*lp;
		int		 i;

		LASSERT(pageidx < rdpg->rp_npages);
		lp = kmap(rdpg->rp_pages[pageidx]);

		/* fill lu pages */
		for (i = 0; i < LU_PAGE_COUNT; i++, lp++, nob -= LU_PAGE_SIZE) {
			rc = filler(env, lp, min_t(size_t, nob, LU_PAGE_SIZE),
				    iops, it, rdpg->rp_attrs, arg);
			if (rc < 0)
				break;
			/* one more lu_page */
			nlupgs++;
			if (rc > 0)
				/* end of index */
				break;
		}
		kunmap(rdpg->rp_pages[i]);
	}

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

	if (rc >= 0)
		rc = min_t(size_t, nlupgs * LU_PAGE_SIZE, rdpg->rp_count);

	RETURN(rc);
}
EXPORT_SYMBOL(dt_index_walk);

/**
 * Walk key/record pairs of an index and copy them into 4KB containers to be
 * transferred over the network. This is the common handler for OBD_IDX_READ
 * RPC processing.
 *
 * \param env - is the environment passed by the caller
 * \param dev - is the dt_device storing the index
 * \param ii  - is the idx_info structure packed by the client in the
 *              OBD_IDX_READ request
 * \param rdpg - is the lu_rdpg descriptor
 *
 * \retval on success, return sum (in bytes) of all filled containers
 * \retval appropriate error otherwise.
 */
int dt_index_read(const struct lu_env *env, struct dt_device *dev,
		  struct idx_info *ii, const struct lu_rdpg *rdpg)
{
	const struct dt_index_features	*feat;
	struct dt_object		*obj;
	int				 rc;
	ENTRY;

	/* rp_count shouldn't be null and should be a multiple of the container
	 * size */
	if (rdpg->rp_count == 0 || (rdpg->rp_count & (LU_PAGE_SIZE - 1)) != 0)
		RETURN(-EFAULT);

	if (!fid_is_quota(&ii->ii_fid) && !fid_is_layout_rbtree(&ii->ii_fid) &&
	    !fid_is_norm(&ii->ii_fid))
		RETURN(-EOPNOTSUPP);

	/* lookup index object subject to the transfer */
	obj = dt_locate(env, dev, &ii->ii_fid);
	if (IS_ERR(obj))
		RETURN(PTR_ERR(obj));
	if (dt_object_exists(obj) == 0)
		GOTO(out, rc = -ENOENT);

	/* fetch index features associated with index object */
	feat = dt_index_feat_select(fid_seq(&ii->ii_fid),
				    lu_object_attr(&obj->do_lu));
	if (IS_ERR(feat))
		GOTO(out, rc = PTR_ERR(feat));

	/* load index feature if not done already */
	if (obj->do_index_ops == NULL) {
		rc = obj->do_ops->do_index_try(env, obj, feat);
		if (rc)
			GOTO(out, rc);
	}

	/* fill ii_flags with supported index features */
	ii->ii_flags &= (II_FL_NOHASH | II_FL_NOKEY | II_FL_VARKEY |
			 II_FL_VARREC);

	if (!(feat->dif_flags & DT_IND_VARKEY))
		ii->ii_keysize = feat->dif_keysize_max;

	if (!(feat->dif_flags & DT_IND_VARREC))
		ii->ii_recsize = feat->dif_recsize_max;

	if (feat->dif_flags & DT_IND_NONUNQ)
		/* key isn't necessarily unique */
		ii->ii_flags |= II_FL_NONUNQ;

	if (!fid_is_layout_rbtree(&ii->ii_fid)) {
		dt_read_lock(env, obj, 0);
		/* fetch object version before walking the index */
		ii->ii_version = dt_version_get(env, obj);
	}

	/* walk the index and fill lu_idxpages with key/record pairs */
	rc = dt_index_walk(env, obj, rdpg, dt_index_page_build, ii);
	if (!fid_is_layout_rbtree(&ii->ii_fid))
		dt_read_unlock(env, obj);

	if (rc == 0) {
		/* index is empty */
		LASSERT(ii->ii_count == 0);
		ii->ii_hash_end = II_END_OFF;
	}

	GOTO(out, rc);
out:
	lu_object_put(env, &obj->do_lu);
	return rc;
}
EXPORT_SYMBOL(dt_index_read);

#ifdef CONFIG_PROC_FS
int lprocfs_dt_blksize_seq_show(struct seq_file *m, void *v)
{
	struct dt_device *dt = m->private;
	struct obd_statfs osfs;

	int rc = dt_statfs(NULL, dt, &osfs);
	if (rc == 0)
		seq_printf(m, "%u\n", (unsigned) osfs.os_bsize);
	return rc;
}
EXPORT_SYMBOL(lprocfs_dt_blksize_seq_show);

int lprocfs_dt_kbytestotal_seq_show(struct seq_file *m, void *v)
{
	struct dt_device *dt = m->private;
	struct obd_statfs osfs;

	int rc = dt_statfs(NULL, dt, &osfs);
	if (rc == 0) {
		__u32 blk_size = osfs.os_bsize >> 10;
		__u64 result = osfs.os_blocks;

		while (blk_size >>= 1)
			result <<= 1;

		seq_printf(m, "%llu\n", result);
	}
	return rc;
}
EXPORT_SYMBOL(lprocfs_dt_kbytestotal_seq_show);

int lprocfs_dt_kbytesfree_seq_show(struct seq_file *m, void *v)
{
	struct dt_device *dt = m->private;
	struct obd_statfs osfs;

	int rc = dt_statfs(NULL, dt, &osfs);
	if (rc == 0) {
		__u32 blk_size = osfs.os_bsize >> 10;
		__u64 result = osfs.os_bfree;

		while (blk_size >>= 1)
			result <<= 1;

		seq_printf(m, "%llu\n", result);
	}
	return rc;
}
EXPORT_SYMBOL(lprocfs_dt_kbytesfree_seq_show);

int lprocfs_dt_kbytesavail_seq_show(struct seq_file *m, void *v)
{
	struct dt_device *dt = m->private;
	struct obd_statfs osfs;

	int rc = dt_statfs(NULL, dt, &osfs);
	if (rc == 0) {
		__u32 blk_size = osfs.os_bsize >> 10;
		__u64 result = osfs.os_bavail;

		while (blk_size >>= 1)
			result <<= 1;

		seq_printf(m, "%llu\n", result);
	}
	return rc;
}
EXPORT_SYMBOL(lprocfs_dt_kbytesavail_seq_show);

int lprocfs_dt_filestotal_seq_show(struct seq_file *m, void *v)
{
	struct dt_device *dt = m->private;
	struct obd_statfs osfs;

	int rc = dt_statfs(NULL, dt, &osfs);
	if (rc == 0)
		seq_printf(m, "%llu\n", osfs.os_files);
	return rc;
}
EXPORT_SYMBOL(lprocfs_dt_filestotal_seq_show);

int lprocfs_dt_filesfree_seq_show(struct seq_file *m, void *v)
{
	struct dt_device *dt = m->private;
	struct obd_statfs osfs;

	int rc = dt_statfs(NULL, dt, &osfs);
	if (rc == 0)
		seq_printf(m, "%llu\n", osfs.os_ffree);
	return rc;
}
EXPORT_SYMBOL(lprocfs_dt_filesfree_seq_show);

#endif /* CONFIG_PROC_FS */