/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License version 2 for more details.  A copy is
 * included in the COPYING file that accompanied this code.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2012, Intel Corporation.
 */
/*
 * lustre/osd-ldiskfs/osd_scrub.c
 *
 * Top-level entry points into osd module
 *
 * The OI scrub is used for rebuilding Object Index files when restores MDT from
 * file-level backup.
 *
 * The otable based iterator scans ldiskfs inode table to feed up layer LFSCK.
 *
 * Author: Fan Yong <yong.fan@whamcloud.com>
 */

#ifndef EXPORT_SYMTAB
# define EXPORT_SYMTAB
#endif
#define DEBUG_SUBSYSTEM S_MDS

#include <lustre/lustre_idl.h>
#include <lustre_disk.h>
#include <dt_object.h>

#include "osd_internal.h"
#include "osd_oi.h"
#include "osd_scrub.h"

#define HALF_SEC	(CFS_HZ >> 1)

static inline struct osd_device *osd_scrub2dev(struct osd_scrub *scrub)
{
	return container_of0(scrub, struct osd_device, od_scrub);
}

static inline struct super_block *osd_scrub2sb(struct osd_scrub *scrub)
{
	return osd_sb(osd_scrub2dev(scrub));
}

static void osd_scrub_file_to_cpu(struct scrub_file *des,
				  struct scrub_file *src)
{
	memcpy(des->sf_uuid, src->sf_uuid, 16);
	des->sf_flags	= le64_to_cpu(src->sf_flags);
	des->sf_magic	= le32_to_cpu(src->sf_magic);
	des->sf_status	= le16_to_cpu(src->sf_status);
	des->sf_param	= le16_to_cpu(src->sf_param);
	des->sf_time_last_complete      =
				le64_to_cpu(src->sf_time_last_complete);
	des->sf_time_latest_start       =
				le64_to_cpu(src->sf_time_latest_start);
	des->sf_time_last_checkpoint    =
				le64_to_cpu(src->sf_time_last_checkpoint);
	des->sf_pos_latest_start	=
				le64_to_cpu(src->sf_pos_latest_start);
	des->sf_pos_last_checkpoint     =
				le64_to_cpu(src->sf_pos_last_checkpoint);
	des->sf_pos_first_inconsistent  =
				le64_to_cpu(src->sf_pos_first_inconsistent);
	des->sf_items_checked		=
				le64_to_cpu(src->sf_items_checked);
	des->sf_items_updated		=
				le64_to_cpu(src->sf_items_updated);
	des->sf_items_failed		=
				le64_to_cpu(src->sf_items_failed);
	des->sf_items_updated_prior     =
				le64_to_cpu(src->sf_items_updated_prior);
	des->sf_run_time	= le32_to_cpu(src->sf_run_time);
	des->sf_success_count   = le32_to_cpu(src->sf_success_count);
	des->sf_oi_count	= le16_to_cpu(src->sf_oi_count);
	memcpy(des->sf_oi_bitmap, src->sf_oi_bitmap, SCRUB_OI_BITMAP_SIZE);
}

static void osd_scrub_file_to_le(struct scrub_file *des,
				 struct scrub_file *src)
{
	memcpy(des->sf_uuid, src->sf_uuid, 16);
	des->sf_flags	= cpu_to_le64(src->sf_flags);
	des->sf_magic	= cpu_to_le32(src->sf_magic);
	des->sf_status	= cpu_to_le16(src->sf_status);
	des->sf_param	= cpu_to_le16(src->sf_param);
	des->sf_time_last_complete      =
				cpu_to_le64(src->sf_time_last_complete);
	des->sf_time_latest_start       =
				cpu_to_le64(src->sf_time_latest_start);
	des->sf_time_last_checkpoint    =
				cpu_to_le64(src->sf_time_last_checkpoint);
	des->sf_pos_latest_start	=
				cpu_to_le64(src->sf_pos_latest_start);
	des->sf_pos_last_checkpoint     =
				cpu_to_le64(src->sf_pos_last_checkpoint);
	des->sf_pos_first_inconsistent  =
				cpu_to_le64(src->sf_pos_first_inconsistent);
	des->sf_items_checked		=
				cpu_to_le64(src->sf_items_checked);
	des->sf_items_updated		=
				cpu_to_le64(src->sf_items_updated);
	des->sf_items_failed		=
				cpu_to_le64(src->sf_items_failed);
	des->sf_items_updated_prior     =
				cpu_to_le64(src->sf_items_updated_prior);
	des->sf_run_time	= cpu_to_le32(src->sf_run_time);
	des->sf_success_count   = cpu_to_le32(src->sf_success_count);
	des->sf_oi_count	= cpu_to_le16(src->sf_oi_count);
	memcpy(des->sf_oi_bitmap, src->sf_oi_bitmap, SCRUB_OI_BITMAP_SIZE);
}

static void osd_scrub_file_init(struct osd_scrub *scrub, __u8 *uuid)
{
	struct scrub_file *sf = &scrub->os_file;

	memset(sf, 0, sizeof(*sf));
	memcpy(sf->sf_uuid, uuid, 16);
	sf->sf_magic = SCRUB_MAGIC_V1;
	sf->sf_status = SS_INIT;
}

void osd_scrub_file_reset(struct osd_scrub *scrub, __u8 *uuid, __u64 flags)
{
	struct scrub_file *sf = &scrub->os_file;

	CDEBUG(D_LFSCK, "Reset OI scrub file, flags = "LPX64"\n", flags);
	memcpy(sf->sf_uuid, uuid, 16);
	sf->sf_status = SS_INIT;
	sf->sf_flags |= flags;
	sf->sf_param = 0;
	sf->sf_run_time = 0;
	sf->sf_time_latest_start = 0;
	sf->sf_time_last_checkpoint = 0;
	sf->sf_pos_latest_start = 0;
	sf->sf_pos_last_checkpoint = 0;
	sf->sf_pos_first_inconsistent = 0;
	sf->sf_items_checked = 0;
	sf->sf_items_updated = 0;
	sf->sf_items_failed = 0;
	sf->sf_items_updated_prior = 0;
	sf->sf_items_noscrub = 0;
	sf->sf_items_igif = 0;
}

static int osd_scrub_file_load(struct osd_scrub *scrub)
{
	loff_t	pos  = 0;
	char   *name = LDISKFS_SB(osd_scrub2sb(scrub))->s_es->s_volume_name;
	int	len  = sizeof(scrub->os_file_disk);
	int	rc;

	rc = osd_ldiskfs_read(scrub->os_inode, &scrub->os_file_disk, len, &pos);
	if (rc == len) {
		struct scrub_file *sf = &scrub->os_file;

		osd_scrub_file_to_cpu(sf, &scrub->os_file_disk);
		if (sf->sf_magic != SCRUB_MAGIC_V1) {
			CWARN("%.16s: invalid scrub magic 0x%x != 0x%x\n,",
			      name, sf->sf_magic, SCRUB_MAGIC_V1);
			/* Process it as new scrub file. */
			rc = -ENOENT;
		} else {
			rc = 0;
		}
	} else if (rc != 0) {
		CERROR("%.16s: fail to load scrub file, expected = %d, "
		       "rc = %d\n", name, len, rc);
		if (rc > 0)
			rc = -EFAULT;
	} else {
		/* return -ENOENT for empty scrub file case. */
		rc = -ENOENT;
	}

	return rc;
}

int osd_scrub_file_store(struct osd_scrub *scrub)
{
	struct osd_device *dev;
	handle_t	  *jh;
	loff_t		   pos     = 0;
	int		   len     = sizeof(scrub->os_file_disk);
	int		   credits;
	int		   rc;

	dev = container_of0(scrub, struct osd_device, od_scrub);
	credits = osd_dto_credits_noquota[DTO_WRITE_BASE] +
		  osd_dto_credits_noquota[DTO_WRITE_BLOCK];
	jh = ldiskfs_journal_start_sb(osd_sb(dev), credits);
	if (IS_ERR(jh)) {
		rc = PTR_ERR(jh);
		CERROR("%.16s: fail to start trans for scrub store, rc = %d\n",
		       LDISKFS_SB(osd_scrub2sb(scrub))->s_es->s_volume_name,rc);
		return rc;
	}

	osd_scrub_file_to_le(&scrub->os_file_disk, &scrub->os_file);
	rc = osd_ldiskfs_write_record(scrub->os_inode, &scrub->os_file_disk,
				      len, 0, &pos, jh);
	ldiskfs_journal_stop(jh);
	if (rc != 0)
		CERROR("%.16s: fail to store scrub file, expected = %d, "
		       "rc = %d\n",
		       LDISKFS_SB(osd_scrub2sb(scrub))->s_es->s_volume_name,
		       len, rc);
	scrub->os_time_last_checkpoint = cfs_time_current();
	scrub->os_time_next_checkpoint = scrub->os_time_last_checkpoint +
				cfs_time_seconds(SCRUB_CHECKPOINT_INTERVAL);
	return rc;
}

static int osd_scrub_prep(struct osd_device *dev)
{
	struct osd_scrub     *scrub  = &dev->od_scrub;
	struct ptlrpc_thread *thread = &scrub->os_thread;
	struct scrub_file    *sf     = &scrub->os_file;
	__u32		      flags  = scrub->os_start_flags;
	int		      rc;
	ENTRY;

	down_write(&scrub->os_rwsem);
	if (flags & SS_SET_FAILOUT)
		sf->sf_param |= SP_FAILOUT;

	if (flags & SS_CLEAR_FAILOUT)
		sf->sf_param &= ~SP_FAILOUT;

	if (flags & SS_RESET)
		osd_scrub_file_reset(scrub,
			LDISKFS_SB(osd_sb(dev))->s_es->s_uuid, sf->sf_flags);

	if (flags & SS_AUTO) {
		scrub->os_full_speed = 1;
		sf->sf_flags |= SF_AUTO;
	} else {
		scrub->os_full_speed = 0;
	}

	if (sf->sf_flags & (SF_RECREATED | SF_INCONSISTENT))
		scrub->os_full_speed = 1;

	scrub->os_in_prior = 0;
	scrub->os_waiting = 0;
	scrub->os_new_checked = 0;
	if (sf->sf_pos_last_checkpoint != 0)
		sf->sf_pos_latest_start = sf->sf_pos_last_checkpoint + 1;
	else
		sf->sf_pos_latest_start = LDISKFS_FIRST_INO(osd_sb(dev));

	scrub->os_pos_current = sf->sf_pos_latest_start;
	sf->sf_status = SS_SCANNING;
	sf->sf_time_latest_start = cfs_time_current_sec();
	sf->sf_time_last_checkpoint = sf->sf_time_latest_start;
	rc = osd_scrub_file_store(scrub);
	if (rc == 0) {
		spin_lock(&scrub->os_lock);
		thread_set_flags(thread, SVC_RUNNING);
		spin_unlock(&scrub->os_lock);
		cfs_waitq_broadcast(&thread->t_ctl_waitq);
	}
	up_write(&scrub->os_rwsem);

	RETURN(rc);
}

static int
osd_scrub_error(struct osd_device *dev, struct osd_inode_id *lid, int rc)
{
	struct osd_scrub  *scrub = &dev->od_scrub;
	struct scrub_file *sf    = &scrub->os_file;

	down_write(&scrub->os_rwsem);
	scrub->os_new_checked++;
	sf->sf_items_failed++;
	if (sf->sf_pos_first_inconsistent == 0 ||
	    sf->sf_pos_first_inconsistent > lid->oii_ino)
		sf->sf_pos_first_inconsistent = lid->oii_ino;
	up_write(&scrub->os_rwsem);
	return sf->sf_param & SP_FAILOUT ? rc : 0;
}

static int
osd_scrub_check_update(struct osd_thread_info *info, struct osd_device *dev,
		       struct osd_idmap_cache *oic)
{
	struct osd_scrub	     *scrub  = &dev->od_scrub;
	struct scrub_file	     *sf     = &scrub->os_file;
	struct osd_inode_id	     *lid2   = &info->oti_id;
	struct lu_fid		     *oi_fid = &info->oti_fid;
	struct osd_inode_id	     *oi_id  = &info->oti_id2;
	handle_t		     *jh     = NULL;
	struct osd_inconsistent_item *oii    = NULL;
	struct inode		     *inode  = NULL;
	struct lu_fid		     *fid    = &oic->oic_fid;
	struct osd_inode_id	     *lid    = &oic->oic_lid;
	struct iam_container	     *bag;
	struct iam_path_descr	     *ipd;
	int			      ops    = DTO_INDEX_UPDATE;
	int			      idx;
	int			      rc;
	ENTRY;

	if (scrub->os_in_prior)
		oii = cfs_list_entry(oic, struct osd_inconsistent_item,
				     oii_cache);

	down_write(&scrub->os_rwsem);
	scrub->os_new_checked++;
	if (lid->oii_ino < sf->sf_pos_latest_start && oii == NULL)
		GOTO(out, rc = 0);

	if (oii != NULL && oii->oii_insert)
		goto iget;

	rc = osd_oi_lookup(info, dev, fid, lid2);
	if (rc != 0) {
		if (rc != -ENOENT)
			GOTO(out, rc);

iget:
		inode = osd_iget(info, dev, lid);
		if (IS_ERR(inode)) {
			rc = PTR_ERR(inode);
			/* Someone removed the inode. */
			if (rc == -ENOENT || rc == -ESTALE)
				rc = 0;
			GOTO(out, rc);
		}

		/* Prevent the inode to be unlinked during OI scrub. */
		mutex_lock(&inode->i_mutex);
		if (unlikely(inode->i_nlink == 0)) {
			mutex_unlock(&inode->i_mutex);
			iput(inode);
			GOTO(out, rc = 0);
		}

		ops = DTO_INDEX_INSERT;
		idx = osd_oi_fid2idx(dev, fid);
		if (unlikely(!ldiskfs_test_bit(idx, sf->sf_oi_bitmap)))
			ldiskfs_set_bit(idx, sf->sf_oi_bitmap);
		sf->sf_flags |= SF_RECREATED;
	} else if (osd_id_eq(lid, lid2)) {
			GOTO(out, rc = 0);
	}

	sf->sf_flags |= SF_INCONSISTENT;
	fid_cpu_to_be(oi_fid, fid);
	osd_id_pack(oi_id, &oic->oic_lid);
	jh = ldiskfs_journal_start_sb(osd_sb(dev),
				osd_dto_credits_noquota[ops]);
	if (IS_ERR(jh)) {
		rc = PTR_ERR(jh);
		CERROR("%.16s: fail to start trans for scrub store, rc = %d\n",
		       LDISKFS_SB(osd_sb(dev))->s_es->s_volume_name, rc);
		GOTO(out, rc);
	}

	bag = &osd_fid2oi(dev, fid)->oi_dir.od_container;
	ipd = osd_idx_ipd_get(info->oti_env, bag);
	if (unlikely(ipd == NULL)) {
		ldiskfs_journal_stop(jh);
		CERROR("%.16s: fail to get ipd for scrub store\n",
			LDISKFS_SB(osd_sb(dev))->s_es->s_volume_name);
		GOTO(out, rc = -ENOMEM);
	}

	if (ops == DTO_INDEX_UPDATE) {
		rc = iam_update(jh, bag, (const struct iam_key *)oi_fid,
				(struct iam_rec *)oi_id, ipd);
	} else {
		rc = iam_insert(jh, bag, (const struct iam_key *)oi_fid,
				(struct iam_rec *)oi_id, ipd);
		if (rc == -EEXIST)
			rc = 1;
	}
	osd_ipd_put(info->oti_env, bag, ipd);
	ldiskfs_journal_stop(jh);
	if (rc == 0) {
		if (scrub->os_in_prior)
			sf->sf_items_updated_prior++;
		else
			sf->sf_items_updated++;
	}

	GOTO(out, rc);

out:
	if (rc < 0) {
		sf->sf_items_failed++;
		if (sf->sf_pos_first_inconsistent == 0 ||
		    sf->sf_pos_first_inconsistent > lid->oii_ino)
			sf->sf_pos_first_inconsistent = lid->oii_ino;
	} else {
		rc = 0;
	}

	if (ops == DTO_INDEX_INSERT) {
		mutex_unlock(&inode->i_mutex);
		iput(inode);
	}
	up_write(&scrub->os_rwsem);

	if (oii != NULL) {
		LASSERT(!cfs_list_empty(&oii->oii_list));

		spin_lock(&scrub->os_lock);
		cfs_list_del_init(&oii->oii_list);
		spin_unlock(&scrub->os_lock);
		OBD_FREE_PTR(oii);
	}
	RETURN(sf->sf_param & SP_FAILOUT ? rc : 0);
}

static int do_osd_scrub_checkpoint(struct osd_scrub *scrub)
{
	struct scrub_file *sf = &scrub->os_file;
	int		   rc;
	ENTRY;

	down_write(&scrub->os_rwsem);
	sf->sf_items_checked += scrub->os_new_checked;
	scrub->os_new_checked = 0;
	sf->sf_pos_last_checkpoint = scrub->os_pos_current;
	sf->sf_time_last_checkpoint = cfs_time_current_sec();
	sf->sf_run_time += cfs_duration_sec(cfs_time_current() + HALF_SEC -
					    scrub->os_time_last_checkpoint);
	rc = osd_scrub_file_store(scrub);
	up_write(&scrub->os_rwsem);

	RETURN(rc);
}

static inline int osd_scrub_checkpoint(struct osd_scrub *scrub)
{
	if (unlikely(cfs_time_beforeq(scrub->os_time_next_checkpoint,
				      cfs_time_current()) &&
		     scrub->os_new_checked > 0))
		return do_osd_scrub_checkpoint(scrub);
	return 0;
}

static void osd_scrub_post(struct osd_scrub *scrub, int result)
{
	struct scrub_file *sf = &scrub->os_file;
	ENTRY;

	down_write(&scrub->os_rwsem);
	spin_lock(&scrub->os_lock);
	thread_set_flags(&scrub->os_thread, SVC_STOPPING);
	spin_unlock(&scrub->os_lock);
	if (scrub->os_new_checked > 0) {
		sf->sf_items_checked += scrub->os_new_checked;
		scrub->os_new_checked = 0;
		sf->sf_pos_last_checkpoint = scrub->os_pos_current;
	}
	sf->sf_time_last_checkpoint = cfs_time_current_sec();
	if (result > 0) {
		sf->sf_status = SS_COMPLETED;
		memset(sf->sf_oi_bitmap, 0, SCRUB_OI_BITMAP_SIZE);
		sf->sf_flags &= ~(SF_RECREATED | SF_INCONSISTENT | SF_AUTO);
		sf->sf_time_last_complete = sf->sf_time_last_checkpoint;
		sf->sf_success_count++;
	} else if (result == 0) {
		if (scrub->os_paused)
			sf->sf_status = SS_PAUSED;
		else
			sf->sf_status = SS_STOPPED;
	} else {
		sf->sf_status = SS_FAILED;
	}
	sf->sf_run_time += cfs_duration_sec(cfs_time_current() + HALF_SEC -
					    scrub->os_time_last_checkpoint);
	result = osd_scrub_file_store(scrub);
	if (result < 0)
		CERROR("%.16s: fail to osd_scrub_post, rc = %d\n",
		       LDISKFS_SB(osd_scrub2sb(scrub))->s_es->s_volume_name,
		       result);
	up_write(&scrub->os_rwsem);

	EXIT;
}

#define SCRUB_NEXT_BREAK	1 /* exit current loop and process next group */
#define SCRUB_NEXT_CONTINUE	2 /* skip current object and process next bit */
#define SCRUB_NEXT_EXIT 	3 /* exit all the loops */
#define SCRUB_NEXT_WAIT 	4 /* wait for free cache slot */
#define SCRUB_NEXT_CRASH	5 /* simulate system crash during OI scrub */
#define SCRUB_NEXT_FATAL	6 /* simulate failure during OI scrub */
#define SCRUB_NEXT_NOSCRUB	7 /* new created object, no scrub on it */
#define SCRUB_NEXT_IGIF 	8 /* IGIF object */

struct osd_iit_param {
	struct super_block *sb;
	struct buffer_head *bitmap;
	ldiskfs_group_t bg;
	__u32 gbase;
	__u32 offset;
};

typedef int (*osd_iit_next_policy)(struct osd_thread_info *info,
				   struct osd_device *dev,
				   struct osd_iit_param *param,
				   struct osd_idmap_cache **oic,
				   int noslot);

typedef int (*osd_iit_exec_policy)(struct osd_thread_info *info,
				   struct osd_device *dev,
				   struct osd_iit_param *param,
				   struct osd_idmap_cache *oic,
				   int *noslot, int rc);

static inline int osd_scrub_has_window(struct osd_scrub *scrub,
				       struct osd_otable_cache *ooc)
{
	return scrub->os_pos_current < ooc->ooc_pos_preload + SCRUB_WINDOW_SIZE;
}

static int osd_iit_next(struct osd_iit_param *param, __u32 *pos)
{
	param->offset = ldiskfs_find_next_bit(param->bitmap->b_data,
			LDISKFS_INODES_PER_GROUP(param->sb), param->offset);
	if (param->offset >= LDISKFS_INODES_PER_GROUP(param->sb)) {
		*pos = 1 + (param->bg+1) * LDISKFS_INODES_PER_GROUP(param->sb);
		return SCRUB_NEXT_BREAK;
	} else {
		*pos = param->gbase + param->offset;
		return 0;
	}
}

static int osd_iit_iget(struct osd_thread_info *info, struct osd_device *dev,
			struct lu_fid *fid, struct osd_inode_id *lid, __u32 pos,
			struct super_block *sb, struct inode **pinode)
{
	struct inode *inode;
	int	      rc;

	osd_id_gen(lid, pos, OSD_OII_NOGEN);
	inode = osd_iget_fid(info, dev, lid, fid);
	if (IS_ERR(inode)) {
		rc = PTR_ERR(inode);
		/* The inode may be removed after bitmap searching, or the
		 * file is new created without inode initialized yet. */
		if (rc == -ENOENT || rc == -ESTALE)
			return SCRUB_NEXT_CONTINUE;

		CERROR("%.16s: fail to read inode, ino# = %u, rc = %d\n",
		       LDISKFS_SB(sb)->s_es->s_volume_name, pos, rc);
		return rc;
	}

	*pinode = inode;
	return 0;
}

static int osd_scrub_next(struct osd_thread_info *info, struct osd_device *dev,
			  struct osd_iit_param *param,
			  struct osd_idmap_cache **oic, int noslot)
{
	struct osd_scrub     *scrub  = &dev->od_scrub;
	struct ptlrpc_thread *thread = &scrub->os_thread;
	struct lu_fid	     *fid;
	struct osd_inode_id  *lid;
	struct inode	     *inode;
	int		      rc;

	if (OBD_FAIL_CHECK(OBD_FAIL_OSD_SCRUB_DELAY) && cfs_fail_val > 0) {
		struct l_wait_info lwi;

		lwi = LWI_TIMEOUT(cfs_time_seconds(cfs_fail_val), NULL, NULL);
		l_wait_event(thread->t_ctl_waitq,
			     !cfs_list_empty(&scrub->os_inconsistent_items) ||
			     !thread_is_running(thread),
			     &lwi);
	}

	if (OBD_FAIL_CHECK(OBD_FAIL_OSD_SCRUB_CRASH)) {
		spin_lock(&scrub->os_lock);
		thread_set_flags(thread, SVC_STOPPING);
		spin_unlock(&scrub->os_lock);
		return SCRUB_NEXT_CRASH;
	}

	if (OBD_FAIL_CHECK(OBD_FAIL_OSD_SCRUB_FATAL))
		return SCRUB_NEXT_FATAL;

	if (unlikely(!thread_is_running(thread)))
		return SCRUB_NEXT_EXIT;

	if (!cfs_list_empty(&scrub->os_inconsistent_items)) {
		struct osd_inconsistent_item *oii;

		oii = cfs_list_entry(scrub->os_inconsistent_items.next,
				     struct osd_inconsistent_item, oii_list);
		*oic = &oii->oii_cache;
		scrub->os_in_prior = 1;
		return 0;
	}

	if (noslot != 0)
		return SCRUB_NEXT_WAIT;

	rc = osd_iit_next(param, &scrub->os_pos_current);
	if (rc != 0)
		return rc;

	*oic = &scrub->os_oic;
	fid = &(*oic)->oic_fid;
	lid = &(*oic)->oic_lid;
	rc = osd_iit_iget(info, dev, fid, lid,
			  scrub->os_pos_current, param->sb, &inode);
	if (rc != 0)
		return rc;

	if (inode->i_state & I_LUSTRE_NOSCRUB) {
		/* Only skip it for the first OI scrub accessing. */
		inode->i_state &= ~I_LUSTRE_NOSCRUB;
		rc = SCRUB_NEXT_NOSCRUB;
	} else if (!fid_is_norm(fid)) {
		rc = SCRUB_NEXT_IGIF;
	}

	iput(inode);
	return rc;
}

static int osd_preload_next(struct osd_thread_info *info,
			    struct osd_device *dev, struct osd_iit_param *param,
			    struct osd_idmap_cache **oic, int noslot)
{
	struct osd_otable_cache *ooc    = &dev->od_otable_it->ooi_cache;
	struct osd_scrub	*scrub;
	struct ptlrpc_thread	*thread;
	struct inode		*inode;
	int			 rc;

	rc = osd_iit_next(param, &ooc->ooc_pos_preload);
	if (rc != 0)
		return rc;

	scrub = &dev->od_scrub;
	thread = &scrub->os_thread;
	if (thread_is_running(thread) &&
	    ooc->ooc_pos_preload >= scrub->os_pos_current)
		return SCRUB_NEXT_EXIT;

	rc = osd_iit_iget(info, dev,
			  &ooc->ooc_cache[ooc->ooc_producer_idx].oic_fid,
			  &ooc->ooc_cache[ooc->ooc_producer_idx].oic_lid,
			  ooc->ooc_pos_preload, param->sb, &inode);
	/* If succeed, it needs to move forward; otherwise up layer LFSCK may
	 * ignore the failure, so it still need to skip the inode next time. */
	ooc->ooc_pos_preload = param->gbase + ++(param->offset);
	if (rc == 0)
		iput(inode);
	return rc;
}

static int osd_scrub_exec(struct osd_thread_info *info, struct osd_device *dev,
			  struct osd_iit_param *param,
			  struct osd_idmap_cache *oic, int *noslot, int rc)
{
	struct l_wait_info	 lwi    = { 0 };
	struct osd_scrub	*scrub  = &dev->od_scrub;
	struct scrub_file	*sf     = &scrub->os_file;
	__u64			*items  = NULL;
	struct ptlrpc_thread	*thread = &scrub->os_thread;
	struct osd_otable_it	*it     = dev->od_otable_it;
	struct osd_otable_cache *ooc    = it ? &it->ooi_cache : NULL;

	switch (rc) {
	case SCRUB_NEXT_CONTINUE:
		goto next;
	case SCRUB_NEXT_WAIT:
		goto wait;
	case SCRUB_NEXT_NOSCRUB:
		items = &sf->sf_items_noscrub;
		break;
	case SCRUB_NEXT_IGIF:
		items = &sf->sf_items_igif;
		break;
	}

	if (items != NULL) {
		down_write(&scrub->os_rwsem);
		scrub->os_new_checked++;
		(*items)++;
		up_write(&scrub->os_rwsem);
		goto next;
	}

	LASSERTF(rc <= 0, "unexpected rc = %d\n", rc);

	if (rc != 0)
		rc = osd_scrub_error(dev, &oic->oic_lid, rc);
	else
		rc = osd_scrub_check_update(info, dev, oic);
	if (rc != 0)
		return rc;

	rc = osd_scrub_checkpoint(scrub);
	if (rc != 0) {
		CERROR("%.16s: fail to checkpoint, pos = %u, rc = %d\n",
		       LDISKFS_SB(param->sb)->s_es->s_volume_name,
		       scrub->os_pos_current, rc);
		/* Continue, as long as the scrub itself can go ahead. */
	}

	if (scrub->os_in_prior) {
		scrub->os_in_prior = 0;
		return 0;
	}

next:
	scrub->os_pos_current = param->gbase + ++(param->offset);
	if (it != NULL && it->ooi_waiting &&
	    ooc->ooc_pos_preload < scrub->os_pos_current) {
		it->ooi_waiting = 0;
		cfs_waitq_broadcast(&thread->t_ctl_waitq);
	}

	if (scrub->os_full_speed || rc == SCRUB_NEXT_CONTINUE)
		return 0;

wait:
	if (osd_scrub_has_window(scrub, ooc)) {
		*noslot = 0;
		return 0;
	}

	scrub->os_waiting = 1;
	l_wait_event(thread->t_ctl_waitq,
		     osd_scrub_has_window(scrub, ooc) ||
		     !cfs_list_empty(&scrub->os_inconsistent_items) ||
		     !thread_is_running(thread),
		     &lwi);
	scrub->os_waiting = 0;

	if (osd_scrub_has_window(scrub, ooc))
		*noslot = 0;
	else
		*noslot = 1;
	return 0;
}

static int osd_preload_exec(struct osd_thread_info *info,
			    struct osd_device *dev, struct osd_iit_param *param,
			    struct osd_idmap_cache *oic, int *noslot, int rc)
{
	struct osd_otable_cache *ooc = &dev->od_otable_it->ooi_cache;

	if (rc == 0) {
		ooc->ooc_cached_items++;
		ooc->ooc_producer_idx = (ooc->ooc_producer_idx + 1) &
					~OSD_OTABLE_IT_CACHE_MASK;
	}
	return rc > 0 ? 0 : rc;
}

#define SCRUB_IT_ALL	1
#define SCRUB_IT_CRASH	2

static int osd_inode_iteration(struct osd_thread_info *info,
			       struct osd_device *dev, __u32 max, int preload)
{
	osd_iit_next_policy   next;
	osd_iit_exec_policy   exec;
	__u32		     *pos;
	__u32		     *count;
	struct osd_iit_param  param;
	__u32		      limit;
	int		      noslot = 0;
	int		      rc;
	ENTRY;

	if (preload == 0) {
		struct osd_scrub *scrub = &dev->od_scrub;

		next = osd_scrub_next;
		exec = osd_scrub_exec;
		pos = &scrub->os_pos_current;
		count = &scrub->os_new_checked;
	} else {
		struct osd_otable_cache *ooc = &dev->od_otable_it->ooi_cache;

		next = osd_preload_next;
		exec = osd_preload_exec;
		pos = &ooc->ooc_pos_preload;
		count = &ooc->ooc_cached_items;
	}
	param.sb = osd_sb(dev);
	limit = le32_to_cpu(LDISKFS_SB(param.sb)->s_es->s_inodes_count);

	while (*pos <= limit && *count < max) {
		struct osd_idmap_cache *oic = NULL;

		param.bg = (*pos - 1) / LDISKFS_INODES_PER_GROUP(param.sb);
		param.offset = (*pos - 1) % LDISKFS_INODES_PER_GROUP(param.sb);
		param.gbase = 1 + param.bg * LDISKFS_INODES_PER_GROUP(param.sb);
		param.bitmap = ldiskfs_read_inode_bitmap(param.sb, param.bg);
		if (param.bitmap == NULL) {
			CERROR("%.16s: fail to read bitmap for %u, "
			       "scrub will stop, urgent mode\n",
			       LDISKFS_SB(param.sb)->s_es->s_volume_name,
			       (__u32)param.bg);
			RETURN(-EIO);
		}

		while (param.offset < LDISKFS_INODES_PER_GROUP(param.sb) &&
		       *count < max) {
			rc = next(info, dev, &param, &oic, noslot);
			switch (rc) {
			case SCRUB_NEXT_BREAK:
				goto next_group;
			case SCRUB_NEXT_EXIT:
				brelse(param.bitmap);
				RETURN(0);
			case SCRUB_NEXT_CRASH:
				brelse(param.bitmap);
				RETURN(SCRUB_IT_CRASH);
			case SCRUB_NEXT_FATAL:
				brelse(param.bitmap);
				RETURN(-EINVAL);
			}

			rc = exec(info, dev, &param, oic, &noslot, rc);
			if (rc != 0) {
				brelse(param.bitmap);
				RETURN(rc);
			}
		}

next_group:
		brelse(param.bitmap);
	}

	if (*pos > limit)
		RETURN(SCRUB_IT_ALL);
	RETURN(0);
}

static int osd_scrub_main(void *args)
{
	struct lu_env	      env;
	struct osd_device    *dev    = (struct osd_device *)args;
	struct osd_scrub     *scrub  = &dev->od_scrub;
	struct ptlrpc_thread *thread = &scrub->os_thread;
	struct super_block   *sb     = osd_sb(dev);
	int		      rc;
	ENTRY;

	cfs_daemonize("OI_scrub");
	rc = lu_env_init(&env, LCT_DT_THREAD);
	if (rc != 0) {
		CERROR("%.16s: OI scrub, fail to init env, rc = %d\n",
		       LDISKFS_SB(sb)->s_es->s_volume_name, rc);
		GOTO(noenv, rc);
	}

	rc = osd_scrub_prep(dev);
	if (rc != 0) {
		CERROR("%.16s: OI scrub, fail to scrub prep, rc = %d\n",
		       LDISKFS_SB(sb)->s_es->s_volume_name, rc);
		GOTO(out, rc);
	}

	if (!scrub->os_full_speed) {
		struct l_wait_info lwi = { 0 };
		struct osd_otable_it *it = dev->od_otable_it;
		struct osd_otable_cache *ooc = &it->ooi_cache;

		l_wait_event(thread->t_ctl_waitq,
			     it->ooi_user_ready || !thread_is_running(thread),
			     &lwi);
		if (unlikely(!thread_is_running(thread)))
			GOTO(post, rc = 0);

		LASSERT(scrub->os_pos_current >= ooc->ooc_pos_preload);
		scrub->os_pos_current = ooc->ooc_pos_preload;
	}

	CDEBUG(D_LFSCK, "OI scrub: flags = 0x%x, pos = %u\n",
	       scrub->os_start_flags, scrub->os_pos_current);

	rc = osd_inode_iteration(osd_oti_get(&env), dev, ~0U, 0);
	if (unlikely(rc == SCRUB_IT_CRASH))
		GOTO(out, rc = -EINVAL);
	GOTO(post, rc);

post:
	osd_scrub_post(scrub, rc);
	CDEBUG(D_LFSCK, "OI scrub: stop, rc = %d, pos = %u\n",
	       rc, scrub->os_pos_current);

out:
	while (!cfs_list_empty(&scrub->os_inconsistent_items)) {
		struct osd_inconsistent_item *oii;

		oii = cfs_list_entry(scrub->os_inconsistent_items.next,
				     struct osd_inconsistent_item, oii_list);
		cfs_list_del_init(&oii->oii_list);
		OBD_FREE_PTR(oii);
	}
	lu_env_fini(&env);

noenv:
	spin_lock(&scrub->os_lock);
	thread_set_flags(thread, SVC_STOPPED);
	cfs_waitq_broadcast(&thread->t_ctl_waitq);
	spin_unlock(&scrub->os_lock);
	return rc;
}

static int do_osd_scrub_start(struct osd_device *dev, __u32 flags)
{
	struct osd_scrub     *scrub  = &dev->od_scrub;
	struct ptlrpc_thread *thread = &scrub->os_thread;
	struct l_wait_info    lwi    = { 0 };
	int		      rc;
	ENTRY;

again:
	/* os_lock: sync status between stop and scrub thread */
	spin_lock(&scrub->os_lock);
	if (thread_is_running(thread)) {
		spin_unlock(&scrub->os_lock);
		RETURN(-EALREADY);
	} else if (unlikely(thread_is_stopping(thread))) {
		spin_unlock(&scrub->os_lock);
		l_wait_event(thread->t_ctl_waitq,
			     thread_is_stopped(thread),
			     &lwi);
		goto again;
	}
	spin_unlock(&scrub->os_lock);

	if (scrub->os_file.sf_status == SS_COMPLETED)
		flags |= SS_RESET;

	scrub->os_start_flags = flags;
	thread_set_flags(thread, 0);
	rc = cfs_create_thread(osd_scrub_main, dev, 0);
	if (rc < 0) {
		CERROR("%.16s: cannot start iteration thread, rc = %d\n",
		       LDISKFS_SB(osd_sb(dev))->s_es->s_volume_name, rc);
		RETURN(rc);
	}

	l_wait_event(thread->t_ctl_waitq,
		     thread_is_running(thread) || thread_is_stopped(thread),
		     &lwi);

	RETURN(0);
}

int osd_scrub_start(struct osd_device *dev)
{
	int rc;
	ENTRY;

	/* od_otable_mutex: prevent curcurrent start/stop */
	mutex_lock(&dev->od_otable_mutex);
	rc = do_osd_scrub_start(dev, SS_AUTO);
	mutex_unlock(&dev->od_otable_mutex);

	RETURN(rc == -EALREADY ? 0 : rc);
}

static void do_osd_scrub_stop(struct osd_scrub *scrub)
{
	struct ptlrpc_thread *thread = &scrub->os_thread;
	struct l_wait_info    lwi    = { 0 };

	/* os_lock: sync status between stop and scrub thread */
	spin_lock(&scrub->os_lock);
	if (!thread_is_init(thread) && !thread_is_stopped(thread)) {
		thread_set_flags(thread, SVC_STOPPING);
		spin_unlock(&scrub->os_lock);
		cfs_waitq_broadcast(&thread->t_ctl_waitq);
		l_wait_event(thread->t_ctl_waitq,
			     thread_is_stopped(thread),
			     &lwi);
		/* Do not skip the last lock/unlock, which can guarantee that
		 * the caller cannot return until the OI scrub thread exit. */
		spin_lock(&scrub->os_lock);
	}
	spin_unlock(&scrub->os_lock);
}

static void osd_scrub_stop(struct osd_device *dev)
{
	/* od_otable_mutex: prevent curcurrent start/stop */
	mutex_lock(&dev->od_otable_mutex);
	dev->od_scrub.os_paused = 1;
	do_osd_scrub_stop(&dev->od_scrub);
	mutex_unlock(&dev->od_otable_mutex);
}

static const char osd_scrub_name[] = "OI_scrub";

int osd_scrub_setup(const struct lu_env *env, struct osd_device *dev)
{
	struct osd_thread_info	   *info   = osd_oti_get(env);
	struct osd_scrub	   *scrub  = &dev->od_scrub;
	struct lvfs_run_ctxt	   *ctxt   = &scrub->os_ctxt;
	struct scrub_file	   *sf     = &scrub->os_file;
	struct osd_inode_id	   *id     = &scrub->os_oic.oic_lid;
	struct super_block	   *sb     = osd_sb(dev);
	struct ldiskfs_super_block *es     = LDISKFS_SB(sb)->s_es;
	struct inode		   *inode;
	struct lvfs_run_ctxt	    saved;
	struct file		   *filp;
	int			    dirty  = 0;
	int			    init   = 0;
	int			    rc     = 0;
	ENTRY;

	memset(scrub, 0, sizeof(*scrub));
	OBD_SET_CTXT_MAGIC(ctxt);
	ctxt->pwdmnt = dev->od_mnt;
	ctxt->pwd = dev->od_mnt->mnt_root;
	ctxt->fs = get_ds();

	cfs_waitq_init(&scrub->os_thread.t_ctl_waitq);
	init_rwsem(&scrub->os_rwsem);
	spin_lock_init(&scrub->os_lock);
	CFS_INIT_LIST_HEAD(&scrub->os_inconsistent_items);

	push_ctxt(&saved, ctxt, NULL);
	filp = filp_open(osd_scrub_name, O_RDWR | O_CREAT, 0644);
	if (IS_ERR(filp))
		RETURN(PTR_ERR(filp));

	scrub->os_inode = igrab(filp->f_dentry->d_inode);
	filp_close(filp, 0);
	pop_ctxt(&saved, ctxt, NULL);

	rc = osd_scrub_file_load(scrub);
	if (rc == -ENOENT) {
		osd_scrub_file_init(scrub, es->s_uuid);
		dirty = 1;
		init = 1;
	} else if (rc != 0) {
		RETURN(rc);
	} else {
		if (memcmp(sf->sf_uuid, es->s_uuid, 16) != 0) {
			osd_scrub_file_reset(scrub, es->s_uuid,SF_INCONSISTENT);
			dirty = 1;
		} else if (sf->sf_status == SS_SCANNING) {
			sf->sf_status = SS_CRASHED;
			dirty = 1;
		}
	}

	if (sf->sf_pos_last_checkpoint != 0)
		scrub->os_pos_current = sf->sf_pos_last_checkpoint + 1;
	else
		scrub->os_pos_current = LDISKFS_FIRST_INO(sb);

	if (dirty != 0) {
		rc = osd_scrub_file_store(scrub);
		if (rc != 0)
			RETURN(rc);
	}

	/* Initialize OI files. */
	rc = osd_oi_init(info, dev);
	if (rc < 0)
		RETURN(rc);

	if (init != 0) {
		rc = __osd_oi_lookup(info, dev, &LU_DOT_LUSTRE_FID, id);
		if (rc == 0) {
			inode = osd_iget(info, dev, id);
			if (IS_ERR(inode)) {
				rc = PTR_ERR(inode);
				/* It is restored from old 2.x backup. */
				if (rc == -ENOENT || rc == -ESTALE) {
					osd_scrub_file_reset(scrub, es->s_uuid,
							     SF_INCONSISTENT);
					rc = osd_scrub_file_store(scrub);
				}
			} else {
				iput(inode);
			}
		} else if (rc == -ENOENT) {
			rc = 0;
		}
	}

	if (rc == 0 && !dev->od_noscrub &&
	    ((sf->sf_status == SS_PAUSED) ||
	     (sf->sf_status == SS_CRASHED &&
	      sf->sf_flags & (SF_RECREATED | SF_INCONSISTENT | SF_AUTO)) ||
	     (sf->sf_status == SS_INIT &&
	      sf->sf_flags & (SF_RECREATED | SF_INCONSISTENT))))
		rc = osd_scrub_start(dev);

	RETURN(rc);
}

void osd_scrub_cleanup(const struct lu_env *env, struct osd_device *dev)
{
	struct osd_scrub *scrub = &dev->od_scrub;

	LASSERT(dev->od_otable_it == NULL);

	if (scrub->os_inode != NULL) {
		osd_scrub_stop(dev);
		iput(scrub->os_inode);
		scrub->os_inode = NULL;
	}
	if (dev->od_oi_table != NULL)
		osd_oi_fini(osd_oti_get(env), dev);
}

static struct dt_it *osd_otable_it_init(const struct lu_env *env,
				       struct dt_object *dt, __u32 attr,
				       struct lustre_capa *capa)
{
	enum dt_otable_it_flags flags = attr >> DT_OTABLE_IT_FLAGS_SHIFT;
	enum dt_otable_it_valid valid = attr & ~DT_OTABLE_IT_FLAGS_MASK;
	struct osd_device      *dev   = osd_dev(dt->do_lu.lo_dev);
	struct osd_scrub       *scrub = &dev->od_scrub;
	struct osd_otable_it   *it;
	__u32			start = 0;
	int			rc;
	ENTRY;

	/* od_otable_mutex: prevent curcurrent init/fini */
	mutex_lock(&dev->od_otable_mutex);
	if (dev->od_otable_it != NULL)
		GOTO(out, it = ERR_PTR(-EALREADY));

	OBD_ALLOC_PTR(it);
	if (it == NULL)
		GOTO(out, it = ERR_PTR(-ENOMEM));

	dev->od_otable_it = it;
	it->ooi_dev = dev;
	it->ooi_cache.ooc_consumer_idx = -1;
	if (flags & DOIF_OUTUSED)
		it->ooi_used_outside = 1;

	if (flags & DOIF_RESET)
		start |= SS_RESET;

	if (valid & DOIV_ERROR_HANDLE) {
		if (flags & DOIF_FAILOUT)
			start |= SS_SET_FAILOUT;
		else
			start |= SS_CLEAR_FAILOUT;
	}

	rc = do_osd_scrub_start(dev, start);
	if (rc == -EALREADY) {
		it->ooi_cache.ooc_pos_preload = scrub->os_pos_current - 1;
	} else if (rc < 0) {
		dev->od_otable_it = NULL;
		OBD_FREE_PTR(it);
		GOTO(out, it = ERR_PTR(-EALREADY));
	} else {
		it->ooi_cache.ooc_pos_preload = scrub->os_pos_current;
	}

	GOTO(out, it);

out:
	mutex_unlock(&dev->od_otable_mutex);
	return (struct dt_it *)it;
}

static void osd_otable_it_fini(const struct lu_env *env, struct dt_it *di)
{
	struct osd_otable_it *it  = (struct osd_otable_it *)di;
	struct osd_device    *dev = it->ooi_dev;

	/* od_otable_mutex: prevent curcurrent init/fini */
	mutex_lock(&dev->od_otable_mutex);
	do_osd_scrub_stop(&dev->od_scrub);
	LASSERT(dev->od_otable_it == it);

	dev->od_otable_it = NULL;
	mutex_unlock(&dev->od_otable_mutex);
	OBD_FREE_PTR(it);
}

/**
 * XXX: Temporary used to notify otable iteration to be paused.
 */
static void osd_otable_it_put(const struct lu_env *env, struct dt_it *di)
{
	struct osd_device *dev = ((struct osd_otable_it *)di)->ooi_dev;

	/* od_otable_mutex: prevent curcurrent init/fini */
	mutex_lock(&dev->od_otable_mutex);
	dev->od_scrub.os_paused = 1;
	mutex_unlock(&dev->od_otable_mutex);
}

/**
 * Set the OSD layer iteration start position as the specified key.
 *
 * The LFSCK out of OSD layer does not know the detail of the key, so if there
 * are several keys, they cannot be compared out of OSD, so call "::get()" for
 * each key, and OSD will select the smallest one by itself.
 */
static int osd_otable_it_get(const struct lu_env *env,
			     struct dt_it *di, const struct dt_key *key)
{
	struct osd_otable_it    *it  = (struct osd_otable_it *)di;
	struct osd_otable_cache *ooc = &it->ooi_cache;
	const char		*str = (const char *)key;
	__u32			 ino;
	ENTRY;

	/* Forbid to set iteration position after iteration started. */
	if (it->ooi_user_ready)
		RETURN(-EPERM);

	if (str[0] == '\0')
		RETURN(-EINVAL);

	if (sscanf(str, "%u", &ino) <= 0)
		RETURN(-EINVAL);

	/* Skip the one that has been processed last time. */
	if (ooc->ooc_pos_preload > ++ino)
		ooc->ooc_pos_preload = ino;

	RETURN(0);
}

static int osd_otable_it_preload(const struct lu_env *env,
				 struct osd_otable_it *it)
{
	struct osd_device       *dev   = it->ooi_dev;
	struct osd_scrub	*scrub = &dev->od_scrub;
	struct osd_otable_cache *ooc   = &it->ooi_cache;
	int			 rc;
	ENTRY;

	rc = osd_inode_iteration(osd_oti_get(env), dev,
				 OSD_OTABLE_IT_CACHE_SIZE, 1);
	if (rc == SCRUB_IT_ALL)
		it->ooi_all_cached = 1;

	CDEBUG(D_LFSCK, "OSD pre-loaded: max = %u, preload = %u, rc = %d\n",
	       le32_to_cpu(LDISKFS_SB(osd_sb(dev))->s_es->s_inodes_count),
	       ooc->ooc_pos_preload, rc);

	if (scrub->os_waiting && osd_scrub_has_window(scrub, ooc)) {
		scrub->os_waiting = 0;
		cfs_waitq_broadcast(&scrub->os_thread.t_ctl_waitq);
	}

	RETURN(rc < 0 ? rc : ooc->ooc_cached_items);
}

static int osd_otable_it_next(const struct lu_env *env, struct dt_it *di)
{
	struct osd_otable_it    *it     = (struct osd_otable_it *)di;
	struct osd_device       *dev    = it->ooi_dev;
	struct osd_scrub	*scrub  = &dev->od_scrub;
	struct osd_otable_cache *ooc    = &it->ooi_cache;
	struct ptlrpc_thread    *thread = &scrub->os_thread;
	struct l_wait_info       lwi    = { 0 };
	int			 rc;
	ENTRY;

	LASSERT(it->ooi_user_ready);

again:
	if (!thread_is_running(thread) && !it->ooi_used_outside)
		RETURN(1);

	if (ooc->ooc_cached_items > 0) {
		ooc->ooc_cached_items--;
		ooc->ooc_consumer_idx = (ooc->ooc_consumer_idx + 1) &
					~OSD_OTABLE_IT_CACHE_MASK;
		RETURN(0);
	}

	if (it->ooi_all_cached) {
		l_wait_event(thread->t_ctl_waitq,
			     !thread_is_running(thread),
			     &lwi);
		RETURN(1);
	}

	it->ooi_waiting = 1;
	l_wait_event(thread->t_ctl_waitq,
		     ooc->ooc_pos_preload < scrub->os_pos_current ||
		     !thread_is_running(thread),
		     &lwi);
	it->ooi_waiting = 0;

	if (!thread_is_running(thread) && !it->ooi_used_outside)
		RETURN(1);

	rc = osd_otable_it_preload(env, it);
	if (rc >= 0)
		goto again;

	RETURN(rc);
}

static struct dt_key *osd_otable_it_key(const struct lu_env *env,
					const struct dt_it *di)
{
	struct osd_otable_it    *it  = (struct osd_otable_it *)di;
	struct osd_otable_cache *ooc = &it->ooi_cache;

	sprintf(it->ooi_key, "%u",
		ooc->ooc_cache[ooc->ooc_consumer_idx].oic_lid.oii_ino);
	return (struct dt_key *)it->ooi_key;
}

static int osd_otable_it_key_size(const struct lu_env *env,
				  const struct dt_it *di)
{
	return sizeof(((struct osd_otable_it *)di)->ooi_key);
}

static int osd_otable_it_rec(const struct lu_env *env, const struct dt_it *di,
			     struct dt_rec *rec, __u32 attr)
{
	struct osd_otable_it    *it  = (struct osd_otable_it *)di;
	struct osd_otable_cache *ooc = &it->ooi_cache;

	*(struct lu_fid *)rec = ooc->ooc_cache[ooc->ooc_consumer_idx].oic_fid;
	return 0;
}

static int osd_otable_it_load(const struct lu_env *env,
			      const struct dt_it *di, __u64 hash)
{
	struct osd_otable_it    *it    = (struct osd_otable_it *)di;
	struct osd_device       *dev   = it->ooi_dev;
	struct osd_otable_cache *ooc   = &it->ooi_cache;
	struct osd_scrub	*scrub = &dev->od_scrub;

	if (it->ooi_user_ready)
		return 0;

	if (ooc->ooc_pos_preload < LDISKFS_FIRST_INO(osd_sb(dev)))
		ooc->ooc_pos_preload = LDISKFS_FIRST_INO(osd_sb(dev));
	it->ooi_user_ready = 1;
	if (!scrub->os_full_speed)
		cfs_waitq_broadcast(&scrub->os_thread.t_ctl_waitq);

	/* Unplug OSD layer iteration by the first next() call. */
	return osd_otable_it_next(env, (struct dt_it *)it);
}

const struct dt_index_operations osd_otable_ops = {
	.dio_it = {
		.init     = osd_otable_it_init,
		.fini     = osd_otable_it_fini,
		.put	  = osd_otable_it_put,
		.get      = osd_otable_it_get,
		.next     = osd_otable_it_next,
		.key      = osd_otable_it_key,
		.key_size = osd_otable_it_key_size,
		.rec      = osd_otable_it_rec,
		.load     = osd_otable_it_load,
	}
};

int osd_oii_insert(struct osd_device *dev, struct osd_idmap_cache *oic,
		   int insert)
{
	struct osd_inconsistent_item *oii;
	struct osd_scrub	     *scrub  = &dev->od_scrub;
	struct ptlrpc_thread	     *thread = &scrub->os_thread;
	int			      wakeup = 0;
	ENTRY;

	OBD_ALLOC_PTR(oii);
	if (unlikely(oii == NULL))
		RETURN(-ENOMEM);

	CFS_INIT_LIST_HEAD(&oii->oii_list);
	oii->oii_cache = *oic;
	oii->oii_insert = insert;

	spin_lock(&scrub->os_lock);
	if (unlikely(!thread_is_running(thread))) {
		spin_unlock(&scrub->os_lock);
		OBD_FREE_PTR(oii);
		RETURN(-EAGAIN);
	}

	if (cfs_list_empty(&scrub->os_inconsistent_items))
		wakeup = 1;
	cfs_list_add_tail(&oii->oii_list, &scrub->os_inconsistent_items);
	spin_unlock(&scrub->os_lock);

	if (wakeup != 0)
		cfs_waitq_broadcast(&thread->t_ctl_waitq);

	RETURN(0);
}

int osd_oii_lookup(struct osd_device *dev, const struct lu_fid *fid,
		   struct osd_inode_id *id)
{
	struct osd_scrub	     *scrub = &dev->od_scrub;
	struct osd_inconsistent_item *oii;
	ENTRY;

	spin_lock(&scrub->os_lock);
	cfs_list_for_each_entry(oii, &scrub->os_inconsistent_items, oii_list) {
		if (lu_fid_eq(fid, &oii->oii_cache.oic_fid)) {
			*id = oii->oii_cache.oic_lid;
			spin_unlock(&scrub->os_lock);
			RETURN(0);
		}
	}
	spin_unlock(&scrub->os_lock);

	RETURN(-ENOENT);
}

static const char *scrub_status_names[] = {
	"init",
	"scanning",
	"completed",
	"failed",
	"stopped",
	"paused",
	"crashed",
	NULL
};

static const char *scrub_flags_names[] = {
	"recreated",
	"inconsistent",
	"auto",
	NULL
};

static const char *scrub_param_names[] = {
	"failout",
	NULL
};

static int scrub_bits_dump(char **buf, int *len, int bits, const char *names[],
			   const char *prefix)
{
	int save = *len;
	int flag;
	int rc;
	int i;

	rc = snprintf(*buf, *len, "%s:%c", prefix, bits != 0 ? ' ' : '\n');
	if (rc <= 0)
		return -ENOSPC;

	*buf += rc;
	*len -= rc;
	for (i = 0, flag = 1; bits != 0; i++, flag = 1 << i) {
		if (flag & bits) {
			bits &= ~flag;
			rc = snprintf(*buf, *len, "%s%c", names[i],
				      bits != 0 ? ',' : '\n');
			if (rc <= 0)
				return -ENOSPC;

			*buf += rc;
			*len -= rc;
		}
	}
	return save - *len;
}

static int scrub_time_dump(char **buf, int *len, __u64 time, const char *prefix)
{
	int rc;

	if (time != 0)
		rc = snprintf(*buf, *len, "%s: "LPU64" seconds\n", prefix,
			      cfs_time_current_sec() - time);
	else
		rc = snprintf(*buf, *len, "%s: N/A\n", prefix);
	if (rc <= 0)
		return -ENOSPC;

	*buf += rc;
	*len -= rc;
	return rc;
}

static int scrub_pos_dump(char **buf, int *len, __u64 pos, const char *prefix)
{
	int rc;

	if (pos != 0)
		rc = snprintf(*buf, *len, "%s: "LPU64"\n", prefix, pos);
	else
		rc = snprintf(*buf, *len, "%s: N/A\n", prefix);
	if (rc <= 0)
		return -ENOSPC;

	*buf += rc;
	*len -= rc;
	return rc;
}

int osd_scrub_dump(struct osd_device *dev, char *buf, int len)
{
	struct osd_scrub  *scrub   = &dev->od_scrub;
	struct scrub_file *sf      = &scrub->os_file;
	__u64		   checked;
	__u64		   speed;
	int		   save    = len;
	int		   ret     = -ENOSPC;
	int		   rc;

	down_read(&scrub->os_rwsem);
	rc = snprintf(buf, len,
		      "name: OI scrub\n"
		      "magic: 0x%x\n"
		      "oi_files: %d\n"
		      "status: %s\n",
		      sf->sf_magic, (int)sf->sf_oi_count,
		      scrub_status_names[sf->sf_status]);
	if (rc <= 0)
		goto out;

	buf += rc;
	len -= rc;
	rc = scrub_bits_dump(&buf, &len, sf->sf_flags, scrub_flags_names,
			     "flags");
	if (rc < 0)
		goto out;

	rc = scrub_bits_dump(&buf, &len, sf->sf_param, scrub_param_names,
			     "param");
	if (rc < 0)
		goto out;

	rc = scrub_time_dump(&buf, &len, sf->sf_time_last_complete,
			     "time_since_last_completed");
	if (rc < 0)
		goto out;

	rc = scrub_time_dump(&buf, &len, sf->sf_time_latest_start,
			     "time_since_latest_start");
	if (rc < 0)
		goto out;

	rc = scrub_time_dump(&buf, &len, sf->sf_time_last_checkpoint,
			     "time_since_last_checkpoint");
	if (rc < 0)
		goto out;

	rc = scrub_pos_dump(&buf, &len, sf->sf_pos_latest_start,
			    "latest_start_position");
	if (rc < 0)
		goto out;

	rc = scrub_pos_dump(&buf, &len, sf->sf_pos_last_checkpoint,
			    "last_checkpoint_position");
	if (rc < 0)
		goto out;

	rc = scrub_pos_dump(&buf, &len, sf->sf_pos_first_inconsistent,
			    "first_failure_position");
	if (rc < 0)
		goto out;

	checked = sf->sf_items_checked + scrub->os_new_checked;
	rc = snprintf(buf, len,
		      "checked: "LPU64"\n"
		      "updated: "LPU64"\n"
		      "failed: "LPU64"\n"
		      "prior_updated: "LPU64"\n"
		      "noscrub: "LPU64"\n"
		      "igif: "LPU64"\n"
		      "success_count: %u\n",
		      checked, sf->sf_items_updated, sf->sf_items_failed,
		      sf->sf_items_updated_prior, sf->sf_items_noscrub,
		      sf->sf_items_igif, sf->sf_success_count);
	if (rc <= 0)
		goto out;

	buf += rc;
	len -= rc;
	speed = checked;
	if (thread_is_running(&scrub->os_thread)) {
		cfs_duration_t duration = cfs_time_current() -
					  scrub->os_time_last_checkpoint;
		__u64 new_checked = scrub->os_new_checked * CFS_HZ;
		__u32 rtime = sf->sf_run_time +
			      cfs_duration_sec(duration + HALF_SEC);

		if (duration != 0)
			do_div(new_checked, duration);
		if (rtime != 0)
			do_div(speed, rtime);
		rc = snprintf(buf, len,
			      "run_time: %u seconds\n"
			      "average_speed: "LPU64" objects/sec\n"
			      "real-time_speed: "LPU64" objects/sec\n"
			      "current_position: %u\n",
			      rtime, speed, new_checked, scrub->os_pos_current);
	} else {
		if (sf->sf_run_time != 0)
			do_div(speed, sf->sf_run_time);
		rc = snprintf(buf, len,
			      "run_time: %u seconds\n"
			      "average_speed: "LPU64" objects/sec\n"
			      "real-time_speed: N/A\n"
			      "current_position: N/A\n",
			      sf->sf_run_time, speed);
	}
	if (rc <= 0)
		goto out;

	buf += rc;
	len -= rc;
	ret = save - len;

out:
	up_read(&scrub->os_rwsem);
	return ret;
}