/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.

 */

#include <sys/spa.h>

#include <sys/spa_impl.h>

#include <sys/zap.h>

#include <sys/dsl_synctask.h>

#include <sys/dmu_tx.h>

#include <sys/dmu_objset.h>

#include <sys/utsname.h>

#include <sys/cmn_err.h>

#include <sys/sunddi.h>

#include "zfs_comutil.h"

#ifdef _KERNEL

#include <sys/zone.h>

#endif

/*

 * Routines to manage the on-disk history log.

 *

 * The history log is stored as a dmu object containing

 * <packed record length, record nvlist> tuples.

 *

 * Where "record nvlist" is a nvlist containing uint64_ts and strings, and

 * "packed record length" is the packed length of the "record nvlist" stored

 * as a little endian uint64_t.

 *

 * The log is implemented as a ring buffer, though the original creation

 * of the pool ('zpool create') is never overwritten.

 *

 * The history log is tracked as object 'spa_t::spa_history'.  The bonus buffer

 * of 'spa_history' stores the offsets for logging/retrieving history as

 * 'spa_history_phys_t'.  'sh_pool_create_len' is the ending offset in bytes of

 * where the 'zpool create' record is stored.  This allows us to never

 * overwrite the original creation of the pool.  'sh_phys_max_off' is the

 * physical ending offset in bytes of the log.  This tells you the length of

 * the buffer. 'sh_eof' is the logical EOF (in bytes).  Whenever a record

 * is added, 'sh_eof' is incremented by the the size of the record.

 * 'sh_eof' is never decremented.  'sh_bof' is the logical BOF (in bytes).

 * This is where the consumer should start reading from after reading in

 * the 'zpool create' portion of the log.

 *

 * 'sh_records_lost' keeps track of how many records have been overwritten

 * and permanently lost.

 */

/* convert a logical offset to physical */

static uint64_t

spa_history_log_to_phys(uint64_t log_off, spa_history_phys_t *shpp)

{

	uint64_t phys_len;

	phys_len = shpp->sh_phys_max_off - shpp->sh_pool_create_len;

	return ((log_off - shpp->sh_pool_create_len) % phys_len

	    + shpp->sh_pool_create_len);

}

void

spa_history_create_obj(spa_t *spa, dmu_tx_t *tx)

{

	dmu_buf_t *dbp;

	spa_history_phys_t *shpp;

	objset_t *mos = spa->spa_meta_objset;

	ASSERT(spa->spa_history == 0);

	spa->spa_history = dmu_object_alloc(mos, DMU_OT_SPA_HISTORY,

	    SPA_MAXBLOCKSIZE, DMU_OT_SPA_HISTORY_OFFSETS,

	    sizeof (spa_history_phys_t), tx);

	VERIFY(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,

	    DMU_POOL_HISTORY, sizeof (uint64_t), 1,

	    &spa->spa_history, tx) == 0);

	VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));

	ASSERT(dbp->db_size >= sizeof (spa_history_phys_t));

	shpp = dbp->db_data;

	dmu_buf_will_dirty(dbp, tx);

	/*

	 * Figure out maximum size of history log.  We set it at

	 */

	shpp->sh_phys_max_off =

	shpp->sh_phys_max_off = MAX(shpp->sh_phys_max_off, 128<<10);

	dmu_buf_rele(dbp, FTAG);

}

/*

 * Change 'sh_bof' to the beginning of the next record.

 */

static int

spa_history_advance_bof(spa_t *spa, spa_history_phys_t *shpp)

{

	objset_t *mos = spa->spa_meta_objset;

	uint64_t firstread, reclen, phys_bof;

	char buf[sizeof (reclen)];

	int err;

	phys_bof = spa_history_log_to_phys(shpp->sh_bof, shpp);

	firstread = MIN(sizeof (reclen), shpp->sh_phys_max_off - phys_bof);

	if ((err = dmu_read(mos, spa->spa_history, phys_bof, firstread,

	    buf, DMU_READ_PREFETCH)) != 0)

		return (err);

	if (firstread != sizeof (reclen)) {

		if ((err = dmu_read(mos, spa->spa_history,

		    shpp->sh_pool_create_len, sizeof (reclen) - firstread,

		    buf + firstread, DMU_READ_PREFETCH)) != 0)

			return (err);

	}

	reclen = LE_64(*((uint64_t *)buf));

	shpp->sh_bof += reclen + sizeof (reclen);

	shpp->sh_records_lost++;

	return (0);

}

static int

spa_history_write(spa_t *spa, void *buf, uint64_t len, spa_history_phys_t *shpp,

    dmu_tx_t *tx)

{

	uint64_t firstwrite, phys_eof;

	objset_t *mos = spa->spa_meta_objset;

	int err;

	ASSERT(MUTEX_HELD(&spa->spa_history_lock));

	/* see if we need to reset logical BOF */

	while (shpp->sh_phys_max_off - shpp->sh_pool_create_len -

	    (shpp->sh_eof - shpp->sh_bof) <= len) {

		if ((err = spa_history_advance_bof(spa, shpp)) != 0) {

			return (err);

		}

	}

	phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp);

	firstwrite = MIN(len, shpp->sh_phys_max_off - phys_eof);

	shpp->sh_eof += len;

	dmu_write(mos, spa->spa_history, phys_eof, firstwrite, buf, tx);

	len -= firstwrite;

	if (len > 0) {

		/* write out the rest at the beginning of physical file */

		dmu_write(mos, spa->spa_history, shpp->sh_pool_create_len,

		    len, (char *)buf + firstwrite, tx);

	}

	return (0);

}

static char *

spa_history_zone()

{

#ifdef _KERNEL

	return (curproc->p_zone->zone_name);

#else

	return ("global");

#endif

}

/*

 * Write out a history event.

 */

/*ARGSUSED*/

static void

spa_history_log_sync(void *arg1, void *arg2, dmu_tx_t *tx)

{

	spa_t		*spa = arg1;

	history_arg_t	*hap = arg2;

	const char	*history_str = hap->ha_history_str;

	objset_t	*mos = spa->spa_meta_objset;

	dmu_buf_t	*dbp;

	spa_history_phys_t *shpp;

	size_t		reclen;

	uint64_t	le_len;

	nvlist_t	*nvrecord;

	char		*record_packed = NULL;

	int		ret;

	/*

	 * If we have an older pool that doesn't have a command

	 * history object, create it now.

	 */

	mutex_enter(&spa->spa_history_lock);

	if (!spa->spa_history)

		spa_history_create_obj(spa, tx);

	mutex_exit(&spa->spa_history_lock);

	/*

	 * Get the offset of where we need to write via the bonus buffer.

	 * Update the offset when the write completes.

	 */

	VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));

	shpp = dbp->db_data;

	dmu_buf_will_dirty(dbp, tx);

#ifdef ZFS_DEBUG

	{

		dmu_object_info_t doi;

		dmu_object_info_from_db(dbp, &doi);

		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);

	}

#endif

	VERIFY(nvlist_alloc(&nvrecord, NV_UNIQUE_NAME, KM_SLEEP) == 0);

	VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_TIME,

	    gethrestime_sec()) == 0);

	VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_WHO, hap->ha_uid) == 0);

	if (hap->ha_zone != NULL)

		VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_ZONE,

		    hap->ha_zone) == 0);

#ifdef _KERNEL

	VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_HOST,

	    utsname.nodename) == 0);

#endif

	if (hap->ha_log_type == LOG_CMD_POOL_CREATE ||

	    hap->ha_log_type == LOG_CMD_NORMAL) {

		VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_CMD,

		    history_str) == 0);

		zfs_dbgmsg("command: %s", history_str);

	} else {

		VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_INT_EVENT,

		    hap->ha_event) == 0);

		VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_TXG,

		    tx->tx_txg) == 0);

		VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_INT_STR,

		    history_str) == 0);

		zfs_dbgmsg("internal %s pool:%s txg:%llu %s",

		    zfs_history_event_names[hap->ha_event], spa_name(spa),

		    (longlong_t)tx->tx_txg, history_str);

	}

	VERIFY(nvlist_size(nvrecord, &reclen, NV_ENCODE_XDR) == 0);

	record_packed = kmem_alloc(reclen, KM_SLEEP);

	VERIFY(nvlist_pack(nvrecord, &record_packed, &reclen,

	    NV_ENCODE_XDR, KM_SLEEP) == 0);

	mutex_enter(&spa->spa_history_lock);

	if (hap->ha_log_type == LOG_CMD_POOL_CREATE)

		VERIFY(shpp->sh_eof == shpp->sh_pool_create_len);

	/* write out the packed length as little endian */

	le_len = LE_64((uint64_t)reclen);

	ret = spa_history_write(spa, &le_len, sizeof (le_len), shpp, tx);

	if (!ret)

		ret = spa_history_write(spa, record_packed, reclen, shpp, tx);

	if (!ret && hap->ha_log_type == LOG_CMD_POOL_CREATE) {

		shpp->sh_pool_create_len += sizeof (le_len) + reclen;

		shpp->sh_bof = shpp->sh_pool_create_len;

	}

	mutex_exit(&spa->spa_history_lock);

	nvlist_free(nvrecord);

	kmem_free(record_packed, reclen);

	dmu_buf_rele(dbp, FTAG);

	strfree(hap->ha_history_str);

	if (hap->ha_zone != NULL)

		strfree(hap->ha_zone);

	kmem_free(hap, sizeof (history_arg_t));

}

/*

 * Write out a history event.

 */

int

spa_history_log(spa_t *spa, const char *history_str, history_log_type_t what)

{

	history_arg_t *ha;

	int err = 0;

	dmu_tx_t *tx;

	ASSERT(what != LOG_INTERNAL);

	tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);

	err = dmu_tx_assign(tx, TXG_WAIT);

	if (err) {

		dmu_tx_abort(tx);

		return (err);

	}

	ha = kmem_alloc(sizeof (history_arg_t), KM_SLEEP);

	ha->ha_history_str = strdup(history_str);

	ha->ha_zone = strdup(spa_history_zone());

	ha->ha_log_type = what;

	ha->ha_uid = crgetuid(CRED());

	/* Kick this off asynchronously; errors are ignored. */

	dsl_sync_task_do_nowait(spa_get_dsl(spa), NULL,

	    spa_history_log_sync, spa, ha, 0, tx);

	dmu_tx_commit(tx);

	/* spa_history_log_sync will free ha and strings */

	return (err);

}

/*

 * Read out the command history.

 */

int

spa_history_get(spa_t *spa, uint64_t *offp, uint64_t *len, char *buf)

{

	objset_t *mos = spa->spa_meta_objset;

	dmu_buf_t *dbp;

	uint64_t read_len, phys_read_off, phys_eof;

	uint64_t leftover = 0;

	spa_history_phys_t *shpp;

	int err;

	/*

	 * If the command history  doesn't exist (older pool),

	 * that's ok, just return ENOENT.

	 */

	if (!spa->spa_history)

		return (ENOENT);

	/*

	 * The history is logged asynchronously, so when they request

	 * the first chunk of history, make sure everything has been

	 * synced to disk so that we get it.

	 */

	if (*offp == 0 && spa_writeable(spa))

		txg_wait_synced(spa_get_dsl(spa), 0);

	if ((err = dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp)) != 0)

		return (err);

	shpp = dbp->db_data;

#ifdef ZFS_DEBUG

	{

		dmu_object_info_t doi;

		dmu_object_info_from_db(dbp, &doi);

		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);

	}

#endif

	mutex_enter(&spa->spa_history_lock);

	phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp);

	if (*offp < shpp->sh_pool_create_len) {

		/* read in just the zpool create history */

		phys_read_off = *offp;

		read_len = MIN(*len, shpp->sh_pool_create_len -

		    phys_read_off);

	} else {

		/*

		 * Need to reset passed in offset to BOF if the passed in

		 * offset has since been overwritten.

		 */

		*offp = MAX(*offp, shpp->sh_bof);

		phys_read_off = spa_history_log_to_phys(*offp, shpp);

		/*

		 * Read up to the minimum of what the user passed down or

		 * the EOF (physical or logical).  If we hit physical EOF,

		 * use 'leftover' to read from the physical BOF.

		 */

		if (phys_read_off <= phys_eof) {

			read_len = MIN(*len, phys_eof - phys_read_off);

		} else {

			read_len = MIN(*len,

			    shpp->sh_phys_max_off - phys_read_off);

			if (phys_read_off + *len > shpp->sh_phys_max_off) {

				leftover = MIN(*len - read_len,

				    phys_eof - shpp->sh_pool_create_len);

			}

		}

	}

	/* offset for consumer to use next */

	*offp += read_len + leftover;

	/* tell the consumer how much you actually read */

	*len = read_len + leftover;

	if (read_len == 0) {

		mutex_exit(&spa->spa_history_lock);

		dmu_buf_rele(dbp, FTAG);

		return (0);

	}

	err = dmu_read(mos, spa->spa_history, phys_read_off, read_len, buf,

	    DMU_READ_PREFETCH);

	if (leftover && err == 0) {

		err = dmu_read(mos, spa->spa_history, shpp->sh_pool_create_len,

		    leftover, buf + read_len, DMU_READ_PREFETCH);

	}

	mutex_exit(&spa->spa_history_lock);

	dmu_buf_rele(dbp, FTAG);

	return (err);

}

static void

log_internal(history_internal_events_t event, spa_t *spa,

    dmu_tx_t *tx, const char *fmt, va_list adx)

{

	history_arg_t *ha;

	/*

	 * If this is part of creating a pool, not everything is

	 * initialized yet, so don't bother logging the internal events.

	 */

	if (tx->tx_txg == TXG_INITIAL)

		return;

	ha = kmem_alloc(sizeof (history_arg_t), KM_SLEEP);

	ha->ha_history_str = kmem_alloc(vsnprintf(NULL, 0, fmt, adx) + 1,

	    KM_SLEEP);

	(void) vsprintf(ha->ha_history_str, fmt, adx);

	ha->ha_log_type = LOG_INTERNAL;

	ha->ha_event = event;

	ha->ha_zone = NULL;

	ha->ha_uid = 0;

	if (dmu_tx_is_syncing(tx)) {

		spa_history_log_sync(spa, ha, tx);

	} else {

		dsl_sync_task_do_nowait(spa_get_dsl(spa), NULL,

		    spa_history_log_sync, spa, ha, 0, tx);

	}

	/* spa_history_log_sync() will free ha and strings */

}

void

spa_history_log_internal(history_internal_events_t event, spa_t *spa,

    dmu_tx_t *tx, const char *fmt, ...)

{

	dmu_tx_t *htx = tx;

	va_list adx;

	/* create a tx if we didn't get one */

	if (tx == NULL) {

		htx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);

		if (dmu_tx_assign(htx, TXG_WAIT) != 0) {

			dmu_tx_abort(htx);

			return;

		}

	}

	va_start(adx, fmt);

	log_internal(event, spa, htx, fmt, adx);

	va_end(adx);

	/* if we didn't get a tx from the caller, commit the one we made */

	if (tx == NULL)

		dmu_tx_commit(htx);

}

void

spa_history_log_version(spa_t *spa, history_internal_events_t event)

{

#ifdef _KERNEL

	uint64_t current_vers = spa_version(spa);

	if (current_vers >= SPA_VERSION_ZPOOL_HISTORY) {

		spa_history_log_internal(event, spa, NULL,

		    "pool spa %llu; zfs spa %llu; zpl %d; uts %s %s %s %s",

		    (u_longlong_t)current_vers, SPA_VERSION, ZPL_VERSION,

		    utsname.nodename, utsname.release, utsname.version,

		    utsname.machine);

	}

	cmn_err(CE_CONT, "!%s version %llu pool %s using %llu",

	    event == LOG_POOL_IMPORT ? "imported" :

	    event == LOG_POOL_CREATE ? "created" : "accessed",

	    (u_longlong_t)current_vers, spa_name(spa), SPA_VERSION);

#endif

}