/*

 * 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

 */

/*

 * Use is subject to license terms.

 */

#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/callb.h>

#define	SET_BOOKMARK(zb, objset, object, level, blkid)  \

{                                                       \

	(zb)->zb_objset = objset;                       \

	(zb)->zb_object = object;                       \

	(zb)->zb_level = level;                         \

	(zb)->zb_blkid = blkid;                         \

}

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;

};

struct traverse_data {

	spa_t *td_spa;

	uint64_t td_objset;

	blkptr_t *td_rootbp;

	uint64_t td_min_txg;

	int td_flags;

	struct prefetch_data *td_pfd;

	blkptr_cb_t *td_func;

	void *td_arg;

};

/* ARGSUSED */

static void

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

{

	struct traverse_data *td = arg;

	zbookmark_t zb;

	if (bp->blk_birth == 0)

		return;

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

		return;

	zb.zb_objset = td->td_objset;

	zb.zb_object = 0;

	zb.zb_level = -1;

	zb.zb_blkid = bp->blk_cksum.zc_word[ZIL_ZC_SEQ];

	VERIFY(0 == td->td_func(td->td_spa, bp, &zb, NULL, td->td_arg));

}

/* ARGSUSED */

static void

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

{

	struct traverse_data *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;

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

			return;

		zb.zb_objset = td->td_objset;

		zb.zb_object = lr->lr_foid;

		zb.zb_level = BP_GET_LEVEL(bp);

		zb.zb_blkid = lr->lr_offset / BP_GET_LSIZE(bp);

		VERIFY(0 == td->td_func(td->td_spa, bp, &zb, NULL, td->td_arg));

	}

}

static void

traverse_zil(struct traverse_data *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 (or, in read-only mode, blocks that *would* be claimed).

	 */

	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(struct traverse_data *td, const dnode_phys_t *dnp,

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

{

	zbookmark_t czb;

	int err = 0;

	arc_buf_t *buf = NULL;

	struct prefetch_data *pd = td->td_pfd;

	if (bp->blk_birth == 0) {

		err = td->td_func(td->td_spa, NULL, 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, bp, zb, dnp, td->td_arg);

		if (err)

			return (err);

	}

	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 = arc_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)

				break;

		}

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

		uint32_t flags = ARC_WAIT;

		int i, j;

		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;

		err = arc_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 && err == 0; i++, dnp++) {

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

				SET_BOOKMARK(&czb, zb->zb_objset,

				    zb->zb_blkid * epb + i,

				    dnp->dn_nlevels - 1, j);

				err = traverse_visitbp(td, dnp, buf,

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

				if (err)

					break;

			}

		}

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

		uint32_t flags = ARC_WAIT;

		objset_phys_t *osp;

		int j;

		err = arc_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;

		traverse_zil(td, &osp->os_zil_header);

		for (j = 0; j < osp->os_meta_dnode.dn_nblkptr; j++) {

			SET_BOOKMARK(&czb, zb->zb_objset, 0,

			    osp->os_meta_dnode.dn_nlevels - 1, j);

			err = traverse_visitbp(td, &osp->os_meta_dnode, buf,

			    (blkptr_t *)&osp->os_meta_dnode.dn_blkptr[j],

			    &czb);

			if (err)

				break;

		}

	}

	if (buf)

		(void) arc_buf_remove_ref(buf, &buf);

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

		err = td->td_func(td->td_spa, bp, zb, dnp, td->td_arg);

	return (err);

}

/* ARGSUSED */

static int

traverse_prefetcher(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,

    const dnode_phys_t *dnp, void *arg)

{

	struct prefetch_data *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))

		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) arc_read_nolock(NULL, spa, bp, NULL, NULL,

	    ZIO_PRIORITY_ASYNC_READ,

	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,

	    &aflags, zb);

	return (0);

}

static void

traverse_prefetch_thread(void *arg)

{

	struct traverse_data *td_main = arg;

	struct traverse_data 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, 0, -1, 0);

	(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_impl(spa_t *spa, uint64_t objset, blkptr_t *rootbp,

    uint64_t txg_start, int flags, blkptr_cb_t func, void *arg)

{

	struct traverse_data td;

	struct prefetch_data pd = { 0 };

	zbookmark_t czb;

	int err;

	td.td_spa = spa;

	td.td_objset = objset;

	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 = 100;

	pd.pd_flags = flags;

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

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

	if (!(flags & TRAVERSE_PREFETCH) ||

	    0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,

	    &td, TQ_NOQUEUE))

		pd.pd_exited = B_TRUE;

	SET_BOOKMARK(&czb, objset, 0, -1, 0);

	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);

}

/*

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

 * in syncing context).

 */

int

traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start, int flags,

    blkptr_cb_t func, void *arg)

{

	return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds->ds_object,

	    &ds->ds_phys->ds_bp, txg_start, flags, func, arg));

}

/*

 * NB: pool must not be changing on-disk (eg, from zdb or sync context).

 */

int

traverse_pool(spa_t *spa, blkptr_cb_t func, void *arg)

{

	int err;

	uint64_t obj;

	dsl_pool_t *dp = spa_get_dsl(spa);

	objset_t *mos = dp->dp_meta_objset;

	/* visit the MOS */

	err = traverse_impl(spa, 0, spa_get_rootblkptr(spa),

	    0, TRAVERSE_PRE, func, arg);

	if (err)

		return (err);

	/* visit each dataset */

	for (obj = 1; err == 0; err = dmu_object_next(mos, &obj, FALSE, 0)) {

		dmu_object_info_t doi;

		err = dmu_object_info(mos, obj, &doi);

		if (err)

			return (err);

		if (doi.doi_type == DMU_OT_DSL_DATASET) {

			dsl_dataset_t *ds;

			rw_enter(&dp->dp_config_rwlock, RW_READER);

			err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);

			rw_exit(&dp->dp_config_rwlock);

			if (err)

				return (err);

			err = traverse_dataset(ds,

			    ds->ds_phys->ds_prev_snap_txg, TRAVERSE_PRE,

			    func, arg);

			dsl_dataset_rele(ds, FTAG);

			if (err)

				return (err);

		}

	}

	if (err == ESRCH)

		err = 0;

	return (err);

}