/*
 * 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/mdd/mdd_lfsck.c
 *
 * Top-level entry points into mdd module
 *
 * LFSCK controller, which scans the whole device through low layer
 * iteration APIs, drives all lfsck compeonents, controls the speed.
 *
 * 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_fid.h>
#include <obd_support.h>

#include "mdd_internal.h"
#include "mdd_lfsck.h"

#define HALF_SEC			(CFS_HZ >> 1)
#define LFSCK_CHECKPOINT_INTERVAL	60

const char lfsck_bookmark_name[] = "lfsck_bookmark";

/* misc functions */

static inline struct mdd_device *mdd_lfsck2mdd(struct md_lfsck *lfsck)
{
	return container_of0(lfsck, struct mdd_device, mdd_lfsck);
}

static inline char *mdd_lfsck2name(struct md_lfsck *lfsck)
{
	struct mdd_device *mdd = mdd_lfsck2mdd(lfsck);

	return mdd2obd_dev(mdd)->obd_name;
}

static inline void mdd_lfsck_component_put(const struct lu_env *env,
					   struct lfsck_component *com)
{
	if (atomic_dec_and_test(&com->lc_ref)) {
		if (com->lc_obj != NULL)
			lu_object_put(env, &com->lc_obj->do_lu);
		if (com->lc_file_ram != NULL)
			OBD_FREE(com->lc_file_ram, com->lc_file_size);
		if (com->lc_file_disk != NULL)
			OBD_FREE(com->lc_file_disk, com->lc_file_size);
		OBD_FREE_PTR(com);
	}
}

static inline struct lfsck_component *
__mdd_lfsck_component_find(struct md_lfsck *lfsck, __u16 type, cfs_list_t *list)
{
	struct lfsck_component *com;

	cfs_list_for_each_entry(com, list, lc_link) {
		if (com->lc_type == type)
			return com;
	}
	return NULL;
}

static void mdd_lfsck_component_cleanup(const struct lu_env *env,
					struct lfsck_component *com)
{
	if (!cfs_list_empty(&com->lc_link))
		cfs_list_del_init(&com->lc_link);
	if (!cfs_list_empty(&com->lc_link_dir))
		cfs_list_del_init(&com->lc_link_dir);

	mdd_lfsck_component_put(env, com);
}

static void __mdd_lfsck_set_speed(struct md_lfsck *lfsck, __u32 limit)
{
	lfsck->ml_bookmark_ram.lb_speed_limit = limit;
	if (limit != LFSCK_SPEED_NO_LIMIT) {
		if (limit > CFS_HZ) {
			lfsck->ml_sleep_rate = limit / CFS_HZ;
			lfsck->ml_sleep_jif = 1;
		} else {
			lfsck->ml_sleep_rate = 1;
			lfsck->ml_sleep_jif = CFS_HZ / limit;
		}
	} else {
		lfsck->ml_sleep_jif = 0;
		lfsck->ml_sleep_rate = 0;
	}
}

static void mdd_lfsck_control_speed(struct md_lfsck *lfsck)
{
	struct ptlrpc_thread *thread = &lfsck->ml_thread;
	struct l_wait_info    lwi;

	if (lfsck->ml_sleep_jif > 0 &&
	    lfsck->ml_new_scanned >= lfsck->ml_sleep_rate) {
		spin_lock(&lfsck->ml_lock);
		if (likely(lfsck->ml_sleep_jif > 0 &&
			   lfsck->ml_new_scanned >= lfsck->ml_sleep_rate)) {
			lwi = LWI_TIMEOUT_INTR(lfsck->ml_sleep_jif, NULL,
					       LWI_ON_SIGNAL_NOOP, NULL);
			spin_unlock(&lfsck->ml_lock);

			l_wait_event(thread->t_ctl_waitq,
				     !thread_is_running(thread),
				     &lwi);
			lfsck->ml_new_scanned = 0;
		} else {
			spin_unlock(&lfsck->ml_lock);
		}
	}
}

/* lfsck_bookmark file ops */

static void inline mdd_lfsck_bookmark_to_cpu(struct lfsck_bookmark *des,
					     struct lfsck_bookmark *src)
{
	des->lb_magic = le32_to_cpu(src->lb_magic);
	des->lb_version = le16_to_cpu(src->lb_version);
	des->lb_param = le16_to_cpu(src->lb_param);
	des->lb_speed_limit = le32_to_cpu(src->lb_speed_limit);
}

static void inline mdd_lfsck_bookmark_to_le(struct lfsck_bookmark *des,
					    struct lfsck_bookmark *src)
{
	des->lb_magic = cpu_to_le32(src->lb_magic);
	des->lb_version = cpu_to_le16(src->lb_version);
	des->lb_param = cpu_to_le16(src->lb_param);
	des->lb_speed_limit = cpu_to_le32(src->lb_speed_limit);
}

static int mdd_lfsck_bookmark_load(const struct lu_env *env,
				   struct md_lfsck *lfsck)
{
	loff_t pos = 0;
	int    len = sizeof(struct lfsck_bookmark);
	int    rc;

	rc = dt_record_read(env, lfsck->ml_bookmark_obj,
			    mdd_buf_get(env, &lfsck->ml_bookmark_disk, len),
			    &pos);
	if (rc == 0) {
		struct lfsck_bookmark *bm = &lfsck->ml_bookmark_ram;

		mdd_lfsck_bookmark_to_cpu(bm, &lfsck->ml_bookmark_disk);
		if (bm->lb_magic != LFSCK_BOOKMARK_MAGIC) {
			CWARN("%.16s: invalid lfsck_bookmark magic "
			      "0x%x != 0x%x\n", mdd_lfsck2name(lfsck),
			      bm->lb_magic, LFSCK_BOOKMARK_MAGIC);
			/* Process it as new lfsck_bookmark. */
			rc = -ENODATA;
		}
	} else {
		if (rc == -EFAULT && pos == 0)
			/* return -ENODATA for empty lfsck_bookmark. */
			rc = -ENODATA;
		else
			CERROR("%.16s: fail to load lfsck_bookmark, "
			       "expected = %d, rc = %d\n",
			       mdd_lfsck2name(lfsck), len, rc);
	}
	return rc;
}

static int mdd_lfsck_bookmark_store(const struct lu_env *env,
				    struct md_lfsck *lfsck)
{
	struct mdd_device *mdd    = mdd_lfsck2mdd(lfsck);
	struct thandle    *handle;
	struct dt_object  *obj    = lfsck->ml_bookmark_obj;
	loff_t		   pos    = 0;
	int		   len    = sizeof(struct lfsck_bookmark);
	int		   rc;
	ENTRY;

	mdd_lfsck_bookmark_to_le(&lfsck->ml_bookmark_disk,
				 &lfsck->ml_bookmark_ram);
	handle = dt_trans_create(env, mdd->mdd_bottom);
	if (IS_ERR(handle)) {
		rc = PTR_ERR(handle);
		CERROR("%.16s: fail to create trans for storing "
		       "lfsck_bookmark: %d\n,", mdd_lfsck2name(lfsck), rc);
		RETURN(rc);
	}

	rc = dt_declare_record_write(env, obj, len, 0, handle);
	if (rc != 0) {
		CERROR("%.16s: fail to declare trans for storing "
		       "lfsck_bookmark: %d\n,", mdd_lfsck2name(lfsck), rc);
		GOTO(out, rc);
	}

	rc = dt_trans_start_local(env, mdd->mdd_bottom, handle);
	if (rc != 0) {
		CERROR("%.16s: fail to start trans for storing "
		       "lfsck_bookmark: %d\n,", mdd_lfsck2name(lfsck), rc);
		GOTO(out, rc);
	}

	rc = dt_record_write(env, obj,
			     mdd_buf_get(env, &lfsck->ml_bookmark_disk, len),
			     &pos, handle);
	if (rc != 0)
		CERROR("%.16s: fail to store lfsck_bookmark, expected = %d, "
		       "rc = %d\n", mdd_lfsck2name(lfsck), len, rc);

	GOTO(out, rc);

out:
	dt_trans_stop(env, mdd->mdd_bottom, handle);
	return rc;
}

static int mdd_lfsck_bookmark_init(const struct lu_env *env,
				   struct md_lfsck *lfsck)
{
	struct lfsck_bookmark *mb = &lfsck->ml_bookmark_ram;
	int rc;

	memset(mb, 0, sizeof(mb));
	mb->lb_magic = LFSCK_BOOKMARK_MAGIC;
	mb->lb_version = LFSCK_VERSION_V1;
	mutex_lock(&lfsck->ml_mutex);
	rc = mdd_lfsck_bookmark_store(env, lfsck);
	mutex_unlock(&lfsck->ml_mutex);
	return rc;
}

/* LFSCK engines */

static int mdd_lfsck_main(void *args)
{
	struct lu_env		 env;
	struct md_lfsck		*lfsck  = (struct md_lfsck *)args;
	struct ptlrpc_thread	*thread = &lfsck->ml_thread;
	struct dt_object	*obj    = lfsck->ml_obj_oit;
	const struct dt_it_ops	*iops   = &obj->do_index_ops->dio_it;
	struct dt_it		*di;
	struct lu_fid		*fid;
	int			 rc;
	ENTRY;

	cfs_daemonize("lfsck");
	rc = lu_env_init(&env, LCT_MD_THREAD | LCT_DT_THREAD);
	if (rc != 0) {
		CERROR("%s: LFSCK, fail to init env, rc = %d\n",
		       mdd_lfsck2name(lfsck), rc);
		GOTO(noenv, rc);
	}

	di = iops->init(&env, obj, lfsck->ml_args_oit, BYPASS_CAPA);
	if (IS_ERR(di)) {
		rc = PTR_ERR(di);
		CERROR("%s: LFSCK, fail to init iteration, rc = %d\n",
		       mdd_lfsck2name(lfsck), rc);
		GOTO(fini_env, rc);
	}

	CDEBUG(D_LFSCK, "LFSCK: flags = 0x%x, pid = %d\n",
	       lfsck->ml_args_oit, cfs_curproc_pid());

	spin_lock(&lfsck->ml_lock);
	thread_set_flags(thread, SVC_RUNNING);
	spin_unlock(&lfsck->ml_lock);
	cfs_waitq_broadcast(&thread->t_ctl_waitq);

	/* The call iops->load() will unplug low layer iteration. */
	rc = iops->load(&env, di, 0);
	if (rc != 0)
		GOTO(out, rc);

	CDEBUG(D_LFSCK, "LFSCK: iteration start: pos = %s\n",
	       (char *)iops->key(&env, di));

	lfsck->ml_new_scanned = 0;
	fid = &mdd_env_info(&env)->mti_fid;
	while (rc == 0) {
		iops->rec(&env, di, (struct dt_rec *)fid, 0);

		/* XXX: here, perform LFSCK when some LFSCK component(s)
		 *      introduced in the future. */
		lfsck->ml_new_scanned++;

		/* XXX: here, make checkpoint when some LFSCK component(s)
		 *      introduced in the future. */

		/* Rate control. */
		mdd_lfsck_control_speed(lfsck);
		if (unlikely(!thread_is_running(thread)))
			GOTO(out, rc = 0);

		rc = iops->next(&env, di);
	}

	GOTO(out, rc);

out:
	if (lfsck->ml_paused) {
		/* XXX: It is hack here: if the lfsck is still running when MDS
		 *	umounts, it should be restarted automatically after MDS
		 *	remounts up.
		 *
		 *	To support that, we need to record the lfsck status in
		 *	the lfsck on-disk bookmark file. But now, there is not
		 *	lfsck component under the lfsck framework. To avoid to
		 *	introduce unnecessary bookmark incompatibility issues,
		 *	we write nothing to the lfsck bookmark file now.
		 *
		 *	Instead, we will reuse dt_it_ops::put() method to notify
		 *	low layer iterator to process such case.
		 *
		 * 	It is just temporary solution, and will be replaced when
		 * 	some lfsck component is introduced in the future. */
		iops->put(&env, di);
		CDEBUG(D_LFSCK, "LFSCK: iteration pasued: pos = %s, rc = %d\n",
		       (char *)iops->key(&env, di), rc);
	} else {
		CDEBUG(D_LFSCK, "LFSCK: iteration stop: pos = %s, rc = %d\n",
		       (char *)iops->key(&env, di), rc);
	}
	iops->fini(&env, di);

fini_env:
	lu_env_fini(&env);

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

/* external interfaces */

int mdd_lfsck_set_speed(const struct lu_env *env, struct md_lfsck *lfsck,
			__u32 limit)
{
	int rc;

	mutex_lock(&lfsck->ml_mutex);
	__mdd_lfsck_set_speed(lfsck, limit);
	rc = mdd_lfsck_bookmark_store(env, lfsck);
	mutex_unlock(&lfsck->ml_mutex);
	return rc;
}

int mdd_lfsck_start(const struct lu_env *env, struct md_lfsck *lfsck,
		    struct lfsck_start *start)
{
	struct lfsck_bookmark  *bk     = &lfsck->ml_bookmark_ram;
	struct ptlrpc_thread   *thread = &lfsck->ml_thread;
	struct lfsck_component *com;
	struct l_wait_info      lwi    = { 0 };
	bool			dirty  = false;
	int			rc     = 0;
	__u16			valid  = 0;
	__u16			flags  = 0;
	ENTRY;

	if (lfsck->ml_obj_oit == NULL)
		RETURN(-ENOTSUPP);

	/* start == NULL means auto trigger paused LFSCK. */
	if (start == NULL && cfs_list_empty(&lfsck->ml_list_scan))
		RETURN(0);

	mutex_lock(&lfsck->ml_mutex);
	spin_lock(&lfsck->ml_lock);
	if (!thread_is_init(thread) && !thread_is_stopped(thread)) {
		spin_unlock(&lfsck->ml_lock);
		mutex_unlock(&lfsck->ml_mutex);
		RETURN(-EALREADY);
	}

	spin_unlock(&lfsck->ml_lock);

	lfsck->ml_paused = 0;
	lfsck->ml_oit_over = 0;
	lfsck->ml_drop_dryrun = 0;
	lfsck->ml_new_scanned = 0;

	/* For auto trigger. */
	if (start == NULL)
		goto trigger;

	start->ls_version = bk->lb_version;
	if (start->ls_valid & LSV_SPEED_LIMIT) {
		__mdd_lfsck_set_speed(lfsck, start->ls_speed_limit);
		dirty = true;
	}

	if (start->ls_valid & LSV_ERROR_HANDLE) {
		valid |= DOIV_ERROR_HANDLE;
		if (start->ls_flags & LPF_FAILOUT)
			flags |= DOIF_FAILOUT;

		if ((start->ls_flags & LPF_FAILOUT) &&
		    !(bk->lb_param & LPF_FAILOUT)) {
			bk->lb_param |= LPF_FAILOUT;
			dirty = true;
		} else if (!(start->ls_flags & LPF_FAILOUT) &&
			   (bk->lb_param & LPF_FAILOUT)) {
			bk->lb_param &= ~LPF_FAILOUT;
			dirty = true;
		}
	}

	if (start->ls_valid & LSV_DRYRUN) {
		if ((start->ls_flags & LPF_DRYRUN) &&
		    !(bk->lb_param & LPF_DRYRUN)) {
			bk->lb_param |= LPF_DRYRUN;
			dirty = true;
		} else if (!(start->ls_flags & LPF_DRYRUN) &&
			   (bk->lb_param & LPF_DRYRUN)) {
			bk->lb_param &= ~LPF_DRYRUN;
			lfsck->ml_drop_dryrun = 1;
			dirty = true;
		}
	}

	if (dirty) {
		rc = mdd_lfsck_bookmark_store(env, lfsck);
		if (rc != 0)
			GOTO(out, rc);
	}

	if (start->ls_flags & LPF_RESET)
		flags |= DOIF_RESET;

	if (start->ls_active != 0) {
		struct lfsck_component *next;
		__u16 type = 1;

		if (start->ls_active == LFSCK_TYPES_ALL)
			start->ls_active = LFSCK_TYPES_SUPPORTED;

		if (start->ls_active & ~LFSCK_TYPES_SUPPORTED) {
			start->ls_active &= ~LFSCK_TYPES_SUPPORTED;
			GOTO(out, rc = -ENOTSUPP);
		}

		cfs_list_for_each_entry_safe(com, next,
					     &lfsck->ml_list_scan, lc_link) {
			if (!(com->lc_type & start->ls_active)) {
				rc = com->lc_ops->lfsck_post(env, com, 0);
				if (rc != 0)
					GOTO(out, rc);
			}
		}

		while (start->ls_active != 0) {
			if (type & start->ls_active) {
				com = __mdd_lfsck_component_find(lfsck, type,
							&lfsck->ml_list_idle);
				if (com != NULL) {
					/* The component status will be updated
					 * when its prep() is called later by
					 * the LFSCK main engine. */
					cfs_list_del_init(&com->lc_link);
					cfs_list_add_tail(&com->lc_link,
							  &lfsck->ml_list_scan);
				}
				start->ls_active &= ~type;
			}
			type <<= 1;
		}
	}

	cfs_list_for_each_entry(com, &lfsck->ml_list_scan, lc_link) {
		start->ls_active |= com->lc_type;
		if (flags & DOIF_RESET) {
			rc = com->lc_ops->lfsck_reset(env, com, false);
			if (rc != 0)
				GOTO(out, rc);
		}
	}

trigger:
	lfsck->ml_args_dir = LUDA_64BITHASH | LUDA_VERIFY;
	if (bk->lb_param & LPF_DRYRUN)
		lfsck->ml_args_dir |= LUDA_VERIFY_DRYRUN;

	if (bk->lb_param & LPF_FAILOUT) {
		valid |= DOIV_ERROR_HANDLE;
		flags |= DOIF_FAILOUT;
	}

	if (!cfs_list_empty(&lfsck->ml_list_scan))
		flags |= DOIF_OUTUSED;

	lfsck->ml_args_oit = (flags << DT_OTABLE_IT_FLAGS_SHIFT) | valid;
	thread_set_flags(thread, 0);
	rc = cfs_create_thread(mdd_lfsck_main, lfsck, 0);
	if (rc < 0)
		CERROR("%s: cannot start LFSCK thread, rc = %d\n",
		       mdd_lfsck2name(lfsck), rc);
	else
		l_wait_event(thread->t_ctl_waitq,
			     thread_is_running(thread) ||
			     thread_is_stopped(thread),
			     &lwi);

	GOTO(out, rc = 0);

out:
	mutex_unlock(&lfsck->ml_mutex);
	return (rc < 0 ? rc : 0);
}

int mdd_lfsck_stop(const struct lu_env *env, struct md_lfsck *lfsck,
		   bool pause)
{
	struct ptlrpc_thread *thread = &lfsck->ml_thread;
	struct l_wait_info    lwi    = { 0 };
	ENTRY;

	mutex_lock(&lfsck->ml_mutex);
	spin_lock(&lfsck->ml_lock);
	if (thread_is_init(thread) || thread_is_stopped(thread)) {
		spin_unlock(&lfsck->ml_lock);
		mutex_unlock(&lfsck->ml_mutex);
		RETURN(-EALREADY);
	}

	if (pause)
		lfsck->ml_paused = 1;
	thread_set_flags(thread, SVC_STOPPING);
	/* The LFSCK thread may be sleeping on low layer wait queue,
	 * wake it up. */
	if (likely(lfsck->ml_di_oit != NULL))
		lfsck->ml_obj_oit->do_index_ops->dio_it.put(env,
							    lfsck->ml_di_oit);
	spin_unlock(&lfsck->ml_lock);

	cfs_waitq_broadcast(&thread->t_ctl_waitq);
	l_wait_event(thread->t_ctl_waitq,
		     thread_is_stopped(thread),
		     &lwi);
	mutex_unlock(&lfsck->ml_mutex);

	RETURN(0);
}

static const struct lu_fid lfsck_it_fid = { .f_seq = FID_SEQ_LOCAL_FILE,
					    .f_oid = OTABLE_IT_OID,
					    .f_ver = 0 };

int mdd_lfsck_setup(const struct lu_env *env, struct mdd_device *mdd)
{
	struct md_lfsck  *lfsck = &mdd->mdd_lfsck;
	struct dt_object *obj;
	int		  rc;
	ENTRY;

	LASSERT(!lfsck->ml_initialized);

	lfsck->ml_initialized = 1;
	mutex_init(&lfsck->ml_mutex);
	spin_lock_init(&lfsck->ml_lock);
	CFS_INIT_LIST_HEAD(&lfsck->ml_list_scan);
	CFS_INIT_LIST_HEAD(&lfsck->ml_list_dir);
	CFS_INIT_LIST_HEAD(&lfsck->ml_list_double_scan);
	CFS_INIT_LIST_HEAD(&lfsck->ml_list_idle);
	cfs_waitq_init(&lfsck->ml_thread.t_ctl_waitq);

	obj = dt_locate(env, mdd->mdd_bottom, &lfsck_it_fid);
	if (IS_ERR(obj))
		RETURN(PTR_ERR(obj));

	lfsck->ml_obj_oit = obj;
	rc = obj->do_ops->do_index_try(env, obj, &dt_otable_features);
	if (rc != 0) {
		if (rc == -ENOTSUPP)
			rc = 0;

		RETURN(rc);
	}

	obj = dt_store_open(env, mdd->mdd_bottom, "", lfsck_bookmark_name,
			    &mdd_env_info(env)->mti_fid);
	if (IS_ERR(obj))
		RETURN(PTR_ERR(obj));

	lfsck->ml_bookmark_obj = obj;
	rc = mdd_lfsck_bookmark_load(env, lfsck);
	if (rc == -ENODATA)
		rc = mdd_lfsck_bookmark_init(env, lfsck);

	/* XXX: LFSCK components initialization to be added here. */

	RETURN(rc);
}

void mdd_lfsck_cleanup(const struct lu_env *env, struct mdd_device *mdd)
{
	struct md_lfsck		*lfsck  = &mdd->mdd_lfsck;
	struct ptlrpc_thread	*thread = &lfsck->ml_thread;
	struct lfsck_component	*com;

	if (!lfsck->ml_initialized)
		return;

	LASSERT(thread_is_init(thread) || thread_is_stopped(thread));

	if (lfsck->ml_obj_oit != NULL) {
		lu_object_put(env, &lfsck->ml_obj_oit->do_lu);
		lfsck->ml_obj_oit = NULL;
	}

	LASSERT(lfsck->ml_obj_dir == NULL);

	if (lfsck->ml_bookmark_obj != NULL) {
		lu_object_put(env, &lfsck->ml_bookmark_obj->do_lu);
		lfsck->ml_bookmark_obj = NULL;
	}

	while (!cfs_list_empty(&lfsck->ml_list_scan)) {
		com = cfs_list_entry(lfsck->ml_list_scan.next,
				     struct lfsck_component,
				     lc_link);
		mdd_lfsck_component_cleanup(env, com);
	}

	LASSERT(cfs_list_empty(&lfsck->ml_list_dir));

	while (!cfs_list_empty(&lfsck->ml_list_double_scan)) {
		com = cfs_list_entry(lfsck->ml_list_double_scan.next,
				     struct lfsck_component,
				     lc_link);
		mdd_lfsck_component_cleanup(env, com);
	}

	while (!cfs_list_empty(&lfsck->ml_list_idle)) {
		com = cfs_list_entry(lfsck->ml_list_idle.next,
				     struct lfsck_component,
				     lc_link);
		mdd_lfsck_component_cleanup(env, com);
	}
}