/*

 * 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 2007 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <sys/zfs_context.h>

#include <sys/dbuf.h>

#include <sys/dnode.h>

#include <sys/dmu.h>

#include <sys/dmu_tx.h>

#include <sys/dmu_objset.h>

#include <sys/dsl_dataset.h>

#include <sys/spa.h>

static void

dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)

{

	dmu_buf_impl_t *db;

	int txgoff = tx->tx_txg & TXG_MASK;

	int nblkptr = dn->dn_phys->dn_nblkptr;

	int old_toplvl = dn->dn_phys->dn_nlevels - 1;

	int new_level = dn->dn_next_nlevels[txgoff];

	int i;

	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);

	/* this dnode can't be paged out because it's dirty */

	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);

	ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));

	ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);

	db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);

	ASSERT(db != NULL);

	dn->dn_phys->dn_nlevels = new_level;

	/* check for existing blkptrs in the dnode */

	for (i = 0; i < nblkptr; i++)

		if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[i]))

			break;

	if (i != nblkptr) {

		/* transfer dnode's block pointers to new indirect block */

		(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);

		ASSERT(db->db.db_data);

		ASSERT(arc_released(db->db_buf));

		ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);

		bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,

		    sizeof (blkptr_t) * nblkptr);

		arc_buf_freeze(db->db_buf);

	}

	/* set dbuf's parent pointers to new indirect buf */

	for (i = 0; i < nblkptr; i++) {

		dmu_buf_impl_t *child = dbuf_find(dn, old_toplvl, i);

		if (child == NULL)

			continue;

		ASSERT3P(child->db_dnode, ==, dn);

		if (child->db_parent && child->db_parent != dn->dn_dbuf) {

			ASSERT(child->db_parent->db_level == db->db_level);

			ASSERT(child->db_blkptr !=

			    &dn->dn_phys->dn_blkptr[child->db_blkid]);

			mutex_exit(&child->db_mtx);

			continue;

		}

		ASSERT(child->db_parent == NULL ||

		    child->db_parent == dn->dn_dbuf);

		child->db_parent = db;

		dbuf_add_ref(db, child);

		if (db->db.db_data)

			child->db_blkptr = (blkptr_t *)db->db.db_data + i;

		else

			child->db_blkptr = NULL;

		dprintf_dbuf_bp(child, child->db_blkptr,

		    "changed db_blkptr to new indirect %s", "");

		mutex_exit(&child->db_mtx);

	}

	bzero(dn->dn_phys->dn_blkptr, sizeof (blkptr_t) * nblkptr);

	dbuf_rele(db, FTAG);

	rw_exit(&dn->dn_struct_rwlock);

}

static void

free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx)

{

	objset_impl_t *os = dn->dn_objset;

	uint64_t bytesfreed = 0;

	int i;

	dprintf("os=%p obj=%llx num=%d\n", os, dn->dn_object, num);

	for (i = 0; i < num; i++, bp++) {

		if (BP_IS_HOLE(bp))

			continue;

		bytesfreed += bp_get_dasize(os->os_spa, bp);

		ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));

		dsl_dataset_block_kill(os->os_dsl_dataset, bp, dn->dn_zio, tx);

		bzero(bp, sizeof (blkptr_t));

	}

	dnode_diduse_space(dn, -bytesfreed);

}

#ifdef ZFS_DEBUG

static void

free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)

{

	int off, num;

	int i, err, epbs;

	uint64_t txg = tx->tx_txg;

	epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;

	off = start - (db->db_blkid * 1<<epbs);

	num = end - start + 1;

	ASSERT3U(off, >=, 0);

	ASSERT3U(num, >=, 0);

	ASSERT3U(db->db_level, >, 0);

	ASSERT3U(db->db.db_size, ==, 1<<db->db_dnode->dn_phys->dn_indblkshift);

	ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT);

	ASSERT(db->db_blkptr != NULL);

	for (i = off; i < off+num; i++) {

		uint64_t *buf;

		dmu_buf_impl_t *child;

		dbuf_dirty_record_t *dr;

		int j;

		ASSERT(db->db_level == 1);

		rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);

		err = dbuf_hold_impl(db->db_dnode, db->db_level-1,

		rw_exit(&db->db_dnode->dn_struct_rwlock);

		if (err == ENOENT)

			continue;

		ASSERT(err == 0);

		ASSERT(child->db_level == 0);

		dr = child->db_last_dirty;

		while (dr && dr->dr_txg > txg)

			dr = dr->dr_next;

		ASSERT(dr == NULL || dr->dr_txg == txg);

		/* data_old better be zeroed */

		if (dr) {

			buf = dr->dt.dl.dr_data->b_data;

			for (j = 0; j < child->db.db_size >> 3; j++) {

				if (buf[j] != 0) {

					panic("freed data not zero: "

					    "child=%p i=%d off=%d num=%d\n",

					    child, i, off, num);

				}

			}

		}

		/*

		 * db_data better be zeroed unless it's dirty in a

		 * future txg.

		 */

		mutex_enter(&child->db_mtx);

		buf = child->db.db_data;

		if (buf != NULL && child->db_state != DB_FILL &&

		    child->db_last_dirty == NULL) {

			for (j = 0; j < child->db.db_size >> 3; j++) {

				if (buf[j] != 0) {

					panic("freed data not zero: "

					    "child=%p i=%d off=%d num=%d\n",

					    child, i, off, num);

				}

			}

		}

		mutex_exit(&child->db_mtx);

		dbuf_rele(child, FTAG);

	}

}

#endif

static int

free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,

    dmu_tx_t *tx)

{

	dnode_t *dn = db->db_dnode;

	blkptr_t *bp;

	dmu_buf_impl_t *subdb;

	uint64_t start, end, dbstart, dbend, i;

	int epbs, shift, err;

	int all = TRUE;

	(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);

	arc_release(db->db_buf, db);

	bp = (blkptr_t *)db->db.db_data;

	epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;

	shift = (db->db_level - 1) * epbs;

	dbstart = db->db_blkid << epbs;

	start = blkid >> shift;

	if (dbstart < start) {

		bp += start - dbstart;

		all = FALSE;

	} else {

		start = dbstart;

	}

	dbend = ((db->db_blkid + 1) << epbs) - 1;

	end = (blkid + nblks - 1) >> shift;

	if (dbend <= end)

		end = dbend;

	else if (all)

		all = trunc;

	ASSERT3U(start, <=, end);

	if (db->db_level == 1) {

		FREE_VERIFY(db, start, end, tx);

		free_blocks(dn, bp, end-start+1, tx);

		arc_buf_freeze(db->db_buf);

		ASSERT(all || db->db_last_dirty);

		return (all);

	}

	for (i = start; i <= end; i++, bp++) {

		if (BP_IS_HOLE(bp))

			continue;

		rw_enter(&dn->dn_struct_rwlock, RW_READER);

		err = dbuf_hold_impl(dn, db->db_level-1, i, TRUE, FTAG, &subdb);

		ASSERT3U(err, ==, 0);

		rw_exit(&dn->dn_struct_rwlock);

		if (free_children(subdb, blkid, nblks, trunc, tx)) {

			ASSERT3P(subdb->db_blkptr, ==, bp);

			free_blocks(dn, bp, 1, tx);

		} else {

			all = FALSE;

		}

		dbuf_rele(subdb, FTAG);

	}

	arc_buf_freeze(db->db_buf);

#ifdef ZFS_DEBUG

	bp -= (end-start)+1;

	for (i = start; i <= end; i++, bp++) {

		if (i == start && blkid != 0)

			continue;

		else if (i == end && !trunc)

			continue;

		ASSERT3U(bp->blk_birth, ==, 0);

	}

#endif

	ASSERT(all || db->db_last_dirty);

	return (all);

}

/*

 * free_range: Traverse the indicated range of the provided file

 * and "free" all the blocks contained there.

 */

static void

dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)

{

	blkptr_t *bp = dn->dn_phys->dn_blkptr;

	dmu_buf_impl_t *db;

	int trunc, start, end, shift, i, err;

	int dnlevel = dn->dn_phys->dn_nlevels;

	if (blkid > dn->dn_phys->dn_maxblkid)

		return;

	ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX);

	trunc = blkid + nblks > dn->dn_phys->dn_maxblkid;

	if (trunc)

		nblks = dn->dn_phys->dn_maxblkid - blkid + 1;

	/* There are no indirect blocks in the object */

	if (dnlevel == 1) {

		if (blkid >= dn->dn_phys->dn_nblkptr) {

			/* this range was never made persistent */

			return;

		}

		ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);

		free_blocks(dn, bp + blkid, nblks, tx);

		if (trunc) {

			uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *

			    (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);

			dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);

			ASSERT(off < dn->dn_phys->dn_maxblkid ||

			    dn->dn_phys->dn_maxblkid == 0 ||

			    dnode_next_offset(dn, FALSE, &off,

			    1, 1, 0) != 0);

		}

		return;

	}

	shift = (dnlevel - 1) * (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT);

	start = blkid >> shift;

	ASSERT(start < dn->dn_phys->dn_nblkptr);

	end = (blkid + nblks - 1) >> shift;

	bp += start;

	for (i = start; i <= end; i++, bp++) {

		if (BP_IS_HOLE(bp))

			continue;

		rw_enter(&dn->dn_struct_rwlock, RW_READER);

		err = dbuf_hold_impl(dn, dnlevel-1, i, TRUE, FTAG, &db);

		ASSERT3U(err, ==, 0);

		rw_exit(&dn->dn_struct_rwlock);

		if (free_children(db, blkid, nblks, trunc, tx)) {

			ASSERT3P(db->db_blkptr, ==, bp);

			free_blocks(dn, bp, 1, tx);

		}

		dbuf_rele(db, FTAG);

	}

	if (trunc) {

		uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *

		    (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);

		dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);

		ASSERT(off < dn->dn_phys->dn_maxblkid ||

		    dn->dn_phys->dn_maxblkid == 0 ||

		    dnode_next_offset(dn, FALSE, &off, 1, 1, 0) != 0);

	}

}

/*

 * Try to kick all the dnodes dbufs out of the cache...

 */

int

dnode_evict_dbufs(dnode_t *dn, int try)

{

	int progress;

	int pass = 0;

	do {

		dmu_buf_impl_t *db, marker;

		int evicting = FALSE;

		progress = FALSE;

		mutex_enter(&dn->dn_dbufs_mtx);

		list_insert_tail(&dn->dn_dbufs, &marker);

		db = list_head(&dn->dn_dbufs);

		for (; db != ▮ db = list_head(&dn->dn_dbufs)) {

			list_remove(&dn->dn_dbufs, db);

			list_insert_tail(&dn->dn_dbufs, db);

			mutex_enter(&db->db_mtx);

			if (db->db_state == DB_EVICTING) {

				progress = TRUE;

				evicting = TRUE;

				mutex_exit(&db->db_mtx);

			} else if (refcount_is_zero(&db->db_holds)) {

				progress = TRUE;

				ASSERT(!arc_released(db->db_buf));

				dbuf_clear(db); /* exits db_mtx for us */

			} else {

				mutex_exit(&db->db_mtx);

			}

		}

		list_remove(&dn->dn_dbufs, &marker);

		/*

		 * NB: we need to drop dn_dbufs_mtx between passes so

		 * that any DB_EVICTING dbufs can make progress.

		 * Ideally, we would have some cv we could wait on, but

		 * since we don't, just wait a bit to give the other

		 * thread a chance to run.

		 */

		mutex_exit(&dn->dn_dbufs_mtx);

		if (evicting)

			delay(1);

		pass++;

		ASSERT(pass < 100); /* sanity check */

	} while (progress);

	/*

	 * This function works fine even if it can't evict everything.

	 * If were only asked to try to evict everything then

	 * return an error if we can't. Otherwise panic as the caller

	 * expects total eviction.

	 */

	if (list_head(&dn->dn_dbufs) != NULL) {

		if (try) {

			return (1);

		} else {

			panic("dangling dbufs (dn=%p, dbuf=%p)\n",

			    dn, list_head(&dn->dn_dbufs));

		}

	}

	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);

	if (dn->dn_bonus && refcount_is_zero(&dn->dn_bonus->db_holds)) {

		mutex_enter(&dn->dn_bonus->db_mtx);

		dbuf_evict(dn->dn_bonus);

		dn->dn_bonus = NULL;

	}

	rw_exit(&dn->dn_struct_rwlock);

	return (0);

}

static void

dnode_undirty_dbufs(list_t *list)

{

	dbuf_dirty_record_t *dr;

	while (dr = list_head(list)) {

		dmu_buf_impl_t *db = dr->dr_dbuf;

		uint64_t txg = dr->dr_txg;

		mutex_enter(&db->db_mtx);

		/* XXX - use dbuf_undirty()? */

		list_remove(list, dr);

		ASSERT(db->db_last_dirty == dr);

		db->db_last_dirty = NULL;

		db->db_dirtycnt -= 1;

		if (db->db_level == 0) {

			ASSERT(db->db_blkid == DB_BONUS_BLKID ||

			    dr->dt.dl.dr_data == db->db_buf);

			dbuf_unoverride(dr);

			mutex_exit(&db->db_mtx);

		} else {

			mutex_exit(&db->db_mtx);

			dnode_undirty_dbufs(&dr->dt.di.dr_children);

		}

		kmem_free(dr, sizeof (dbuf_dirty_record_t));

		dbuf_rele(db, (void *)(uintptr_t)txg);

	}

}

static void

dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)

{

	int txgoff = tx->tx_txg & TXG_MASK;

	ASSERT(dmu_tx_is_syncing(tx));

	dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);

	(void) dnode_evict_dbufs(dn, 0);

	ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);

	/*

	 * XXX - It would be nice to assert this, but we may still

	 * have residual holds from async evictions from the arc...

	 *

	 * zfs_obj_to_path() also depends on this being

	 * commented out.

	 *

	 * ASSERT3U(refcount_count(&dn->dn_holds), ==, 1);

	 */

	/* Undirty next bits */

	dn->dn_next_nlevels[txgoff] = 0;

	dn->dn_next_indblkshift[txgoff] = 0;

	dn->dn_next_blksz[txgoff] = 0;

	/* free up all the blocks in the file. */

	dnode_sync_free_range(dn, 0, dn->dn_phys->dn_maxblkid+1, tx);

	ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0);

	/* ASSERT(blkptrs are zero); */

	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);

	ASSERT(dn->dn_type != DMU_OT_NONE);

	ASSERT(dn->dn_free_txg > 0);

	if (dn->dn_allocated_txg != dn->dn_free_txg)

		dbuf_will_dirty(dn->dn_dbuf, tx);

	bzero(dn->dn_phys, sizeof (dnode_phys_t));

	mutex_enter(&dn->dn_mtx);

	dn->dn_type = DMU_OT_NONE;

	dn->dn_maxblkid = 0;

	dn->dn_allocated_txg = 0;

	mutex_exit(&dn->dn_mtx);

	ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);

	dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);

	/*

	 * Now that we've released our hold, the dnode may

	 * be evicted, so we musn't access it.

	 */

}