/*

 * 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/zfs_context.h>

#include <sys/dmu_objset.h>

#include <sys/dmu_traverse.h>

#include <sys/dsl_dataset.h>

#include <sys/dsl_dir.h>

#include <sys/dsl_pool.h>

#include <sys/dnode.h>

#include <sys/spa.h>

#include <sys/zio.h>

#include <sys/dmu_impl.h>

#include <sys/sa.h>

#include <sys/sa_impl.h>

#include <sys/callb.h>

int zfs_pd_blks_max = 100;

typedef struct prefetch_data {

	kmutex_t pd_mtx;

	kcondvar_t pd_cv;

	int pd_blks_max;

	int pd_blks_fetched;

	int pd_flags;

	boolean_t pd_cancel;

	boolean_t pd_exited;

} prefetch_data_t;

typedef struct traverse_data {

	spa_t *td_spa;

	uint64_t td_objset;

	blkptr_t *td_rootbp;

	uint64_t td_min_txg;

	int td_flags;

	prefetch_data_t *td_pfd;

	blkptr_cb_t *td_func;

	void *td_arg;

} traverse_data_t;

static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,

    arc_buf_t *buf, uint64_t objset, uint64_t object);

static int

traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)

{

	traverse_data_t *td = arg;

	zbookmark_t zb;

	if (bp->blk_birth == 0)

		return (0);

	if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(td->td_spa))

		return (0);

	SET_BOOKMARK(&zb, td->td_objset, ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,

	    bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);

	(void) td->td_func(td->td_spa, zilog, bp, NULL, &zb, NULL, td->td_arg);

	return (0);

}

static int

traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)

{

	traverse_data_t *td = arg;

	if (lrc->lrc_txtype == TX_WRITE) {

		lr_write_t *lr = (lr_write_t *)lrc;

		blkptr_t *bp = &lr->lr_blkptr;

		zbookmark_t zb;

		if (bp->blk_birth == 0)

			return (0);

		if (claim_txg == 0 || bp->blk_birth < claim_txg)

			return (0);

		SET_BOOKMARK(&zb, td->td_objset, lr->lr_foid,

		    ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));

		(void) td->td_func(td->td_spa, zilog, bp, NULL, &zb, NULL,

		    td->td_arg);

	}

	return (0);

}

static void

traverse_zil(traverse_data_t *td, zil_header_t *zh)

{

	uint64_t claim_txg = zh->zh_claim_txg;

	zilog_t *zilog;

	/*

	 * We only want to visit blocks that have been claimed but not yet

	 * replayed; plus, in read-only mode, blocks that are already stable.

	 */

	if (claim_txg == 0 && spa_writeable(td->td_spa))

		return;

	zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);

	(void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,

	    claim_txg);

	zil_free(zilog);

}

static int

traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,

    arc_buf_t *pbuf, blkptr_t *bp, const zbookmark_t *zb)

{

	zbookmark_t czb;

	int err = 0, lasterr = 0;

	arc_buf_t *buf = NULL;

	prefetch_data_t *pd = td->td_pfd;

	boolean_t hard = td->td_flags & TRAVERSE_HARD;

		err = td->td_func(td->td_spa, NULL, NULL, pbuf, zb, dnp,

		    td->td_arg);

		return (err);

	}

	if (bp->blk_birth <= td->td_min_txg)

		return (0);

	if (pd && !pd->pd_exited &&

	    ((pd->pd_flags & TRAVERSE_PREFETCH_DATA) ||

	    BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0)) {

		mutex_enter(&pd->pd_mtx);

		ASSERT(pd->pd_blks_fetched >= 0);

		while (pd->pd_blks_fetched == 0 && !pd->pd_exited)

			cv_wait(&pd->pd_cv, &pd->pd_mtx);

		pd->pd_blks_fetched--;

		cv_broadcast(&pd->pd_cv);

		mutex_exit(&pd->pd_mtx);

	}

	if (td->td_flags & TRAVERSE_PRE) {

		err = td->td_func(td->td_spa, NULL, bp, pbuf, zb, dnp,

		    td->td_arg);

		if (err == TRAVERSE_VISIT_NO_CHILDREN)

			return (0);

	}

	if (BP_GET_LEVEL(bp) > 0) {

		uint32_t flags = ARC_WAIT;

		int i;

		blkptr_t *cbp;

		int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;

		err = dsl_read(NULL, td->td_spa, bp, pbuf,

		    arc_getbuf_func, &buf,

		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);

		if (err)

			return (err);

		/* recursively visitbp() blocks below this */

		cbp = buf->b_data;

		for (i = 0; i < epb; i++, cbp++) {

			SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,

			    zb->zb_level - 1,

			    zb->zb_blkid * epb + i);

			err = traverse_visitbp(td, dnp, buf, cbp, &czb);

			if (err) {

				if (!hard)

					break;

				lasterr = err;

			}

		}

	} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {

		uint32_t flags = ARC_WAIT;

		int i;

		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;

		err = dsl_read(NULL, td->td_spa, bp, pbuf,

		    arc_getbuf_func, &buf,

		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);

		if (err)

			return (err);

		/* recursively visitbp() blocks below this */

		dnp = buf->b_data;

		for (i = 0; i < epb; i++, dnp++) {

			err = traverse_dnode(td, dnp, buf, zb->zb_objset,

			    zb->zb_blkid * epb + i);

			if (err) {

				if (!hard)

					break;

				lasterr = err;

			}

		}

	} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {

		uint32_t flags = ARC_WAIT;

		objset_phys_t *osp;

		dnode_phys_t *dnp;

		err = dsl_read_nolock(NULL, td->td_spa, bp,

		    arc_getbuf_func, &buf,

		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);

		if (err)

			return (err);

		osp = buf->b_data;

		dnp = &osp->os_meta_dnode;

		err = traverse_dnode(td, dnp, buf, zb->zb_objset,

		    DMU_META_DNODE_OBJECT);

		if (err && hard) {

			lasterr = err;

			err = 0;

		}

		if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {

			dnp = &osp->os_userused_dnode;

			err = traverse_dnode(td, dnp, buf, zb->zb_objset,

			    DMU_USERUSED_OBJECT);

		}

		if (err && hard) {

			lasterr = err;

			err = 0;

		}

		if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {

			dnp = &osp->os_groupused_dnode;

			err = traverse_dnode(td, dnp, buf, zb->zb_objset,

			    DMU_GROUPUSED_OBJECT);

		}

	}

	if (buf)

		(void) arc_buf_remove_ref(buf, &buf);

	if (err == 0 && lasterr == 0 && (td->td_flags & TRAVERSE_POST)) {

		err = td->td_func(td->td_spa, NULL, bp, pbuf, zb, dnp,

		    td->td_arg);

	}

	return (err != 0 ? err : lasterr);

}

static int

traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,

    arc_buf_t *buf, uint64_t objset, uint64_t object)

{

	int j, err = 0, lasterr = 0;

	zbookmark_t czb;

	boolean_t hard = (td->td_flags & TRAVERSE_HARD);

	for (j = 0; j < dnp->dn_nblkptr; j++) {

		SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);

		err = traverse_visitbp(td, dnp, buf,

		    (blkptr_t *)&dnp->dn_blkptr[j], &czb);

		if (err) {

			if (!hard)

				break;

			lasterr = err;

		}

	}

	if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {

		SET_BOOKMARK(&czb, objset,

		    object, 0, DMU_SPILL_BLKID);

		err = traverse_visitbp(td, dnp, buf,

		    (blkptr_t *)&dnp->dn_spill, &czb);

		if (err) {

			if (!hard)

				return (err);

			lasterr = err;

		}

	}

	return (err != 0 ? err : lasterr);

}

/* ARGSUSED */

static int

traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,

    arc_buf_t *pbuf, const zbookmark_t *zb, const dnode_phys_t *dnp,

    void *arg)

{

	prefetch_data_t *pfd = arg;

	uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;

	ASSERT(pfd->pd_blks_fetched >= 0);

	if (pfd->pd_cancel)

		return (EINTR);

	if (bp == NULL || !((pfd->pd_flags & TRAVERSE_PREFETCH_DATA) ||

	    BP_GET_TYPE(bp) == DMU_OT_DNODE || BP_GET_LEVEL(bp) > 0) ||

	    BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG)

		return (0);

	mutex_enter(&pfd->pd_mtx);

	while (!pfd->pd_cancel && pfd->pd_blks_fetched >= pfd->pd_blks_max)

		cv_wait(&pfd->pd_cv, &pfd->pd_mtx);

	pfd->pd_blks_fetched++;

	cv_broadcast(&pfd->pd_cv);

	mutex_exit(&pfd->pd_mtx);

	(void) dsl_read(NULL, spa, bp, pbuf, NULL, NULL,

	    ZIO_PRIORITY_ASYNC_READ,

	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,

	    &aflags, zb);

	return (0);

}

static void

traverse_prefetch_thread(void *arg)

{

	traverse_data_t *td_main = arg;

	traverse_data_t td = *td_main;

	zbookmark_t czb;

	td.td_func = traverse_prefetcher;

	td.td_arg = td_main->td_pfd;

	td.td_pfd = NULL;

	SET_BOOKMARK(&czb, td.td_objset,

	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);

	(void) traverse_visitbp(&td, NULL, NULL, td.td_rootbp, &czb);

	mutex_enter(&td_main->td_pfd->pd_mtx);

	td_main->td_pfd->pd_exited = B_TRUE;

	cv_broadcast(&td_main->td_pfd->pd_cv);

	mutex_exit(&td_main->td_pfd->pd_mtx);

}

/*

 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are

 * in syncing context).

 */

static int

{

	traverse_data_t td;

	prefetch_data_t pd = { 0 };

	zbookmark_t czb;

	int err;

	td.td_spa = spa;

	td.td_rootbp = rootbp;

	td.td_min_txg = txg_start;

	td.td_func = func;

	td.td_arg = arg;

	td.td_pfd = &pd;

	td.td_flags = flags;

	pd.pd_blks_max = zfs_pd_blks_max;

	pd.pd_flags = flags;

	mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);

	cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);

	/* See comment on ZIL traversal in dsl_scan_visitds. */

	if (ds != NULL && !dsl_dataset_is_snapshot(ds)) {

		objset_t *os;

		err = dmu_objset_from_ds(ds, &os);

		if (err)

			return (err);

		traverse_zil(&td, &os->os_zil_header);

	}

	if (!(flags & TRAVERSE_PREFETCH) ||

	    0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,

	    &td, TQ_NOQUEUE))

		pd.pd_exited = B_TRUE;

	SET_BOOKMARK(&czb, td.td_objset,

	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);

	err = traverse_visitbp(&td, NULL, NULL, rootbp, &czb);

	mutex_enter(&pd.pd_mtx);

	pd.pd_cancel = B_TRUE;

	cv_broadcast(&pd.pd_cv);

	while (!pd.pd_exited)

		cv_wait(&pd.pd_cv, &pd.pd_mtx);

	mutex_exit(&pd.pd_mtx);

	mutex_destroy(&pd.pd_mtx);

	cv_destroy(&pd.pd_cv);

	return (err);