/*

 * 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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.

 */

#include <sys/dsl_pool.h>

#include <sys/dsl_dataset.h>

#include <sys/dsl_prop.h>

#include <sys/dsl_dir.h>

#include <sys/dsl_synctask.h>

#include <sys/dsl_scan.h>

#include <sys/dnode.h>

#include <sys/dmu_tx.h>

#include <sys/dmu_objset.h>

#include <sys/arc.h>

#include <sys/zap.h>

#include <sys/zio.h>

#include <sys/zfs_context.h>

#include <sys/fs/zfs.h>

#include <sys/zfs_znode.h>

#include <sys/spa_impl.h>

#include <sys/dsl_deadlist.h>

int zfs_no_write_throttle = 0;

int zfs_write_limit_shift = 3;			/* 1/8th of physical memory */

int zfs_txg_synctime_ms = 1000;		/* target millisecs to sync a txg */

uint64_t zfs_write_limit_min = 32 << 20;	/* min write limit is 32MB */

uint64_t zfs_write_limit_max = 0;		/* max data payload per txg */

uint64_t zfs_write_limit_inflated = 0;

uint64_t zfs_write_limit_override = 0;

kmutex_t zfs_write_limit_lock;

static pgcnt_t old_physmem = 0;

int

dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)

{

	uint64_t obj;

	int err;

	err = zap_lookup(dp->dp_meta_objset,

	    dp->dp_root_dir->dd_phys->dd_child_dir_zapobj,

	    name, sizeof (obj), 1, &obj);

	if (err)

		return (err);

	return (dsl_dir_open_obj(dp, obj, name, dp, ddp));

}

static dsl_pool_t *

dsl_pool_open_impl(spa_t *spa, uint64_t txg)

{

	dsl_pool_t *dp;

	blkptr_t *bp = spa_get_rootblkptr(spa);

	dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);

	dp->dp_spa = spa;

	dp->dp_meta_rootbp = *bp;

	rw_init(&dp->dp_config_rwlock, NULL, RW_DEFAULT, NULL);

	dp->dp_write_limit = zfs_write_limit_min;

	txg_init(dp, txg);

	txg_list_create(&dp->dp_dirty_datasets,

	    offsetof(dsl_dataset_t, ds_dirty_link));

	txg_list_create(&dp->dp_dirty_dirs,

	    offsetof(dsl_dir_t, dd_dirty_link));

	txg_list_create(&dp->dp_sync_tasks,

	    offsetof(dsl_sync_task_group_t, dstg_node));

	list_create(&dp->dp_synced_datasets, sizeof (dsl_dataset_t),

	    offsetof(dsl_dataset_t, ds_synced_link));

	mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);

	dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri,

	    1, 4, 0);

	return (dp);

}

int

dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)

{

	int err;

	dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);

	dsl_dir_t *dd;

	dsl_dataset_t *ds;

	uint64_t obj;

	rw_enter(&dp->dp_config_rwlock, RW_WRITER);

	err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,

	    &dp->dp_meta_objset);

	if (err)

		goto out;

	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,

	    DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,

	    &dp->dp_root_dir_obj);

	if (err)

		goto out;

	err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,

	    NULL, dp, &dp->dp_root_dir);

	if (err)

		goto out;

	err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);

	if (err)

		goto out;

	if (spa_version(spa) >= SPA_VERSION_ORIGIN) {

		err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);

		if (err)

			goto out;

		err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj,

		    FTAG, &ds);

		if (err == 0) {

			err = dsl_dataset_hold_obj(dp,

			    ds->ds_phys->ds_prev_snap_obj, dp,

			    &dp->dp_origin_snap);

			dsl_dataset_rele(ds, FTAG);

		}

		dsl_dir_close(dd, dp);

		if (err)

			goto out;

	}

	if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {

		err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME,

		    &dp->dp_free_dir);

		if (err)

			goto out;

		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,

		    DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);

		if (err)

			goto out;

		VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,

		    dp->dp_meta_objset, obj));

	}

	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,

	    DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,

	    &dp->dp_tmp_userrefs_obj);

	if (err == ENOENT)

		err = 0;

	if (err)

		goto out;

	err = dsl_scan_init(dp, txg);

out:

	rw_exit(&dp->dp_config_rwlock);

	if (err)

		dsl_pool_close(dp);

	else

		*dpp = dp;

	return (err);

}

void

dsl_pool_close(dsl_pool_t *dp)

{

	/* drop our references from dsl_pool_open() */

	/*

	 * Since we held the origin_snap from "syncing" context (which

	 * includes pool-opening context), it actually only got a "ref"

	 * and not a hold, so just drop that here.

	 */

	if (dp->dp_origin_snap)

		dsl_dataset_drop_ref(dp->dp_origin_snap, dp);

	if (dp->dp_mos_dir)

		dsl_dir_close(dp->dp_mos_dir, dp);

	if (dp->dp_free_dir)

		dsl_dir_close(dp->dp_free_dir, dp);

	if (dp->dp_root_dir)

		dsl_dir_close(dp->dp_root_dir, dp);

	bpobj_close(&dp->dp_free_bpobj);

	/* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */

	if (dp->dp_meta_objset)

		dmu_objset_evict(dp->dp_meta_objset);

	txg_list_destroy(&dp->dp_dirty_datasets);

	txg_list_destroy(&dp->dp_sync_tasks);

	txg_list_destroy(&dp->dp_dirty_dirs);

	list_destroy(&dp->dp_synced_datasets);

	arc_flush(dp->dp_spa);

	txg_fini(dp);

	dsl_scan_fini(dp);

	rw_destroy(&dp->dp_config_rwlock);

	mutex_destroy(&dp->dp_lock);

	taskq_destroy(dp->dp_vnrele_taskq);

	if (dp->dp_blkstats)

		kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));

	kmem_free(dp, sizeof (dsl_pool_t));

}

dsl_pool_t *

dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)

{

	int err;

	dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);

	dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);

	objset_t *os;

	dsl_dataset_t *ds;

	uint64_t obj;

	/* create and open the MOS (meta-objset) */

	dp->dp_meta_objset = dmu_objset_create_impl(spa,

	    NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);

	/* create the pool directory */

	err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,

	    DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);

	ASSERT3U(err, ==, 0);

	/* Initialize scan structures */

	VERIFY3U(0, ==, dsl_scan_init(dp, txg));

	/* create and open the root dir */

	dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);

	VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,

	    NULL, dp, &dp->dp_root_dir));

	/* create and open the meta-objset dir */

	(void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);

	VERIFY(0 == dsl_pool_open_special_dir(dp,

	    MOS_DIR_NAME, &dp->dp_mos_dir));

	if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {

		/* create and open the free dir */

		(void) dsl_dir_create_sync(dp, dp->dp_root_dir,

		    FREE_DIR_NAME, tx);

		VERIFY(0 == dsl_pool_open_special_dir(dp,

		    FREE_DIR_NAME, &dp->dp_free_dir));

		/* create and open the free_bplist */

		obj = bpobj_alloc(dp->dp_meta_objset, SPA_MAXBLOCKSIZE, tx);

		VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,

		    DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);

		VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,

		    dp->dp_meta_objset, obj));

	}

	if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)

		dsl_pool_create_origin(dp, tx);

	/* create the root dataset */

	obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);

	/* create the root objset */

	VERIFY(0 == dsl_dataset_hold_obj(dp, obj, FTAG, &ds));

	os = dmu_objset_create_impl(dp->dp_spa, ds,

	    dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx);

#ifdef _KERNEL

	zfs_create_fs(os, kcred, zplprops, tx);

#endif

	dsl_dataset_rele(ds, FTAG);

	dmu_tx_commit(tx);

	return (dp);

}

static int

deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)

{

	dsl_deadlist_t *dl = arg;

	dsl_deadlist_insert(dl, bp, tx);

	return (0);

}

void

dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)

{

	zio_t *zio;

	dmu_tx_t *tx;

	dsl_dir_t *dd;

	dsl_dataset_t *ds;

	dsl_sync_task_group_t *dstg;

	objset_t *mos = dp->dp_meta_objset;

	hrtime_t start, write_time;

	uint64_t data_written;

	int err;

	/*

	 * We need to copy dp_space_towrite() before doing

	 * dsl_sync_task_group_sync(), because

	 * dsl_dataset_snapshot_reserve_space() will increase

	 * dp_space_towrite but not actually write anything.

	 */

	data_written = dp->dp_space_towrite[txg & TXG_MASK];

	tx = dmu_tx_create_assigned(dp, txg);

	dp->dp_read_overhead = 0;

	start = gethrtime();

	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);

	while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {

		/*

		 * We must not sync any non-MOS datasets twice, because

		 * we may have taken a snapshot of them.  However, we

		 * may sync newly-created datasets on pass 2.

		 */

		ASSERT(!list_link_active(&ds->ds_synced_link));

		list_insert_tail(&dp->dp_synced_datasets, ds);

		dsl_dataset_sync(ds, zio, tx);

	}

	DTRACE_PROBE(pool_sync__1setup);

	err = zio_wait(zio);

	write_time = gethrtime() - start;

	ASSERT(err == 0);

	DTRACE_PROBE(pool_sync__2rootzio);

	for (ds = list_head(&dp->dp_synced_datasets); ds;

	    ds = list_next(&dp->dp_synced_datasets, ds))

		dmu_objset_do_userquota_updates(ds->ds_objset, tx);

	/*

	 * Sync the datasets again to push out the changes due to

	 * userspace updates.  This must be done before we process the

	 * sync tasks, because that could cause a snapshot of a dataset

	 * whose ds_bp will be rewritten when we do this 2nd sync.

	 */

	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);

	while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {

		ASSERT(list_link_active(&ds->ds_synced_link));

		dmu_buf_rele(ds->ds_dbuf, ds);

		dsl_dataset_sync(ds, zio, tx);

	}

	err = zio_wait(zio);

	/*

	 * Move dead blocks from the pending deadlist to the on-disk

	 * deadlist.

	 */

	for (ds = list_head(&dp->dp_synced_datasets); ds;

	    ds = list_next(&dp->dp_synced_datasets, ds)) {

		bplist_iterate(&ds->ds_pending_deadlist,

		    deadlist_enqueue_cb, &ds->ds_deadlist, tx);

	}

	while (dstg = txg_list_remove(&dp->dp_sync_tasks, txg)) {

		/*

		 * No more sync tasks should have been added while we

		 * were syncing.

		 */

		ASSERT(spa_sync_pass(dp->dp_spa) == 1);

		dsl_sync_task_group_sync(dstg, tx);

	}

	DTRACE_PROBE(pool_sync__3task);

	start = gethrtime();

	while (dd = txg_list_remove(&dp->dp_dirty_dirs, txg))

		dsl_dir_sync(dd, tx);

	write_time += gethrtime() - start;

	start = gethrtime();

	if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||

	    list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) {

		zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);

		dmu_objset_sync(mos, zio, tx);

		err = zio_wait(zio);

		ASSERT(err == 0);

		dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");

		spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);

	}

	write_time += gethrtime() - start;

	DTRACE_PROBE2(pool_sync__4io, hrtime_t, write_time,

	    hrtime_t, dp->dp_read_overhead);

	write_time -= dp->dp_read_overhead;

	dmu_tx_commit(tx);

	dp->dp_space_towrite[txg & TXG_MASK] = 0;

	ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0);

	/*

	 * If the write limit max has not been explicitly set, set it

	 * to a fraction of available physical memory (default 1/8th).

	 * Note that we must inflate the limit because the spa

	 * inflates write sizes to account for data replication.

	 * Check this each sync phase to catch changing memory size.

	 */

	if (physmem != old_physmem && zfs_write_limit_shift) {

		mutex_enter(&zfs_write_limit_lock);

		old_physmem = physmem;

		zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;

		zfs_write_limit_inflated = MAX(zfs_write_limit_min,

		    spa_get_asize(dp->dp_spa, zfs_write_limit_max));

		mutex_exit(&zfs_write_limit_lock);

	}

	/*

	 * Attempt to keep the sync time consistent by adjusting the

	 * amount of write traffic allowed into each transaction group.

	 * Weight the throughput calculation towards the current value:

	 * 	thru = 3/4 old_thru + 1/4 new_thru

	 *

	 * Note: write_time is in nanosecs, so write_time/MICROSEC

	 * yields millisecs

	 */

	ASSERT(zfs_write_limit_min > 0);

	if (data_written > zfs_write_limit_min / 8 && write_time > MICROSEC) {

		uint64_t throughput = data_written / (write_time / MICROSEC);

		if (dp->dp_throughput)

			dp->dp_throughput = throughput / 4 +

			    3 * dp->dp_throughput / 4;

		else

			dp->dp_throughput = throughput;

		dp->dp_write_limit = MIN(zfs_write_limit_inflated,

		    MAX(zfs_write_limit_min,

		    dp->dp_throughput * zfs_txg_synctime_ms));

	}

}

void

dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)

{

	dsl_dataset_t *ds;

	objset_t *os;

	while (ds = list_head(&dp->dp_synced_datasets)) {

		list_remove(&dp->dp_synced_datasets, ds);

		os = ds->ds_objset;

		zil_clean(os->os_zil, txg);

		ASSERT(!dmu_objset_is_dirty(os, txg));

		dmu_buf_rele(ds->ds_dbuf, ds);

	}

	ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));

}

/*

 * TRUE if the current thread is the tx_sync_thread or if we

 * are being called from SPA context during pool initialization.

 */

int

dsl_pool_sync_context(dsl_pool_t *dp)

{

	return (curthread == dp->dp_tx.tx_sync_thread ||

	    spa_get_dsl(dp->dp_spa) == NULL);

}

uint64_t

dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)

{

	uint64_t space, resv;

	/*

	 * Reserve about 1.6% (1/64), or at least 32MB, for allocation

	 * efficiency.

	 * XXX The intent log is not accounted for, so it must fit

	 * within this slop.

	 *

	 * If we're trying to assess whether it's OK to do a free,

	 * cut the reservation in half to allow forward progress

	 * (e.g. make it possible to rm(1) files from a full pool).

	 */

	space = spa_get_dspace(dp->dp_spa);

	resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1);

	if (netfree)

		resv >>= 1;

	return (space - resv);

}