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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 
     22 /*
     23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
     24  * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
     25  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
     26  */
     27 
     28 #include <sys/zfs_context.h>
     29 #include <sys/dbuf.h>
     30 #include <sys/dnode.h>
     31 #include <sys/dmu.h>
     32 #include <sys/dmu_tx.h>
     33 #include <sys/dmu_objset.h>
     34 #include <sys/dsl_dataset.h>
     35 #include <sys/spa.h>
     36 #include <sys/range_tree.h>
     37 #include <sys/zfeature.h>
     38 
     39 static void
     40 dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
     41 {
     42 	dmu_buf_impl_t *db;
     43 	int txgoff = tx->tx_txg & TXG_MASK;
     44 	int nblkptr = dn->dn_phys->dn_nblkptr;
     45 	int old_toplvl = dn->dn_phys->dn_nlevels - 1;
     46 	int new_level = dn->dn_next_nlevels[txgoff];
     47 	int i;
     48 
     49 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
     50 
     51 	/* this dnode can't be paged out because it's dirty */
     52 	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
     53 	ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
     54 	ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);
     55 
     56 	db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
     57 	ASSERT(db != NULL);
     58 
     59 	dn->dn_phys->dn_nlevels = new_level;
     60 	dprintf("os=%p obj=%llu, increase to %d\n", dn->dn_objset,
     61 	    dn->dn_object, dn->dn_phys->dn_nlevels);
     62 
     63 	/* transfer dnode's block pointers to new indirect block */
     64 	(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
     65 	ASSERT(db->db.db_data);
     66 	ASSERT(arc_released(db->db_buf));
     67 	ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
     68 	bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,
     69 	    sizeof (blkptr_t) * nblkptr);
     70 	arc_buf_freeze(db->db_buf);
     71 
     72 	/* set dbuf's parent pointers to new indirect buf */
     73 	for (i = 0; i < nblkptr; i++) {
     74 		dmu_buf_impl_t *child =
     75 		    dbuf_find(dn->dn_objset, dn->dn_object, old_toplvl, i);
     76 
     77 		if (child == NULL)
     78 			continue;
     79 #ifdef	DEBUG
     80 		DB_DNODE_ENTER(child);
     81 		ASSERT3P(DB_DNODE(child), ==, dn);
     82 		DB_DNODE_EXIT(child);
     83 #endif	/* DEBUG */
     84 		if (child->db_parent && child->db_parent != dn->dn_dbuf) {
     85 			ASSERT(child->db_parent->db_level == db->db_level);
     86 			ASSERT(child->db_blkptr !=
     87 			    &dn->dn_phys->dn_blkptr[child->db_blkid]);
     88 			mutex_exit(&child->db_mtx);
     89 			continue;
     90 		}
     91 		ASSERT(child->db_parent == NULL ||
     92 		    child->db_parent == dn->dn_dbuf);
     93 
     94 		child->db_parent = db;
     95 		dbuf_add_ref(db, child);
     96 		if (db->db.db_data)
     97 			child->db_blkptr = (blkptr_t *)db->db.db_data + i;
     98 		else
     99 			child->db_blkptr = NULL;
    100 		dprintf_dbuf_bp(child, child->db_blkptr,
    101 		    "changed db_blkptr to new indirect %s", "");
    102 
    103 		mutex_exit(&child->db_mtx);
    104 	}
    105 
    106 	bzero(dn->dn_phys->dn_blkptr, sizeof (blkptr_t) * nblkptr);
    107 
    108 	dbuf_rele(db, FTAG);
    109 
    110 	rw_exit(&dn->dn_struct_rwlock);
    111 }
    112 
    113 static void
    114 free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx)
    115 {
    116 	dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
    117 	uint64_t bytesfreed = 0;
    118 
    119 	dprintf("ds=%p obj=%llx num=%d\n", ds, dn->dn_object, num);
    120 
    121 	for (int i = 0; i < num; i++, bp++) {
    122 		if (BP_IS_HOLE(bp))
    123 			continue;
    124 
    125 		bytesfreed += dsl_dataset_block_kill(ds, bp, tx, B_FALSE);
    126 		ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));
    127 
    128 		/*
    129 		 * Save some useful information on the holes being
    130 		 * punched, including logical size, type, and indirection
    131 		 * level. Retaining birth time enables detection of when
    132 		 * holes are punched for reducing the number of free
    133 		 * records transmitted during a zfs send.
    134 		 */
    135 
    136 		uint64_t lsize = BP_GET_LSIZE(bp);
    137 		dmu_object_type_t type = BP_GET_TYPE(bp);
    138 		uint64_t lvl = BP_GET_LEVEL(bp);
    139 
    140 		bzero(bp, sizeof (blkptr_t));
    141 
    142 		if (spa_feature_is_active(dn->dn_objset->os_spa,
    143 		    SPA_FEATURE_HOLE_BIRTH)) {
    144 			BP_SET_LSIZE(bp, lsize);
    145 			BP_SET_TYPE(bp, type);
    146 			BP_SET_LEVEL(bp, lvl);
    147 			BP_SET_BIRTH(bp, dmu_tx_get_txg(tx), 0);
    148 		}
    149 	}
    150 	dnode_diduse_space(dn, -bytesfreed);
    151 }
    152 
    153 #ifdef ZFS_DEBUG
    154 static void
    155 free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
    156 {
    157 	int off, num;
    158 	int i, err, epbs;
    159 	uint64_t txg = tx->tx_txg;
    160 	dnode_t *dn;
    161 
    162 	DB_DNODE_ENTER(db);
    163 	dn = DB_DNODE(db);
    164 	epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
    165 	off = start - (db->db_blkid * 1<<epbs);
    166 	num = end - start + 1;
    167 
    168 	ASSERT3U(off, >=, 0);
    169 	ASSERT3U(num, >=, 0);
    170 	ASSERT3U(db->db_level, >, 0);
    171 	ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
    172 	ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT);
    173 	ASSERT(db->db_blkptr != NULL);
    174 
    175 	for (i = off; i < off+num; i++) {
    176 		uint64_t *buf;
    177 		dmu_buf_impl_t *child;
    178 		dbuf_dirty_record_t *dr;
    179 		int j;
    180 
    181 		ASSERT(db->db_level == 1);
    182 
    183 		rw_enter(&dn->dn_struct_rwlock, RW_READER);
    184 		err = dbuf_hold_impl(dn, db->db_level-1,
    185 		    (db->db_blkid << epbs) + i, TRUE, FALSE, FTAG, &child);
    186 		rw_exit(&dn->dn_struct_rwlock);
    187 		if (err == ENOENT)
    188 			continue;
    189 		ASSERT(err == 0);
    190 		ASSERT(child->db_level == 0);
    191 		dr = child->db_last_dirty;
    192 		while (dr && dr->dr_txg > txg)
    193 			dr = dr->dr_next;
    194 		ASSERT(dr == NULL || dr->dr_txg == txg);
    195 
    196 		/* data_old better be zeroed */
    197 		if (dr) {
    198 			buf = dr->dt.dl.dr_data->b_data;
    199 			for (j = 0; j < child->db.db_size >> 3; j++) {
    200 				if (buf[j] != 0) {
    201 					panic("freed data not zero: "
    202 					    "child=%p i=%d off=%d num=%d\n",
    203 					    (void *)child, i, off, num);
    204 				}
    205 			}
    206 		}
    207 
    208 		/*
    209 		 * db_data better be zeroed unless it's dirty in a
    210 		 * future txg.
    211 		 */
    212 		mutex_enter(&child->db_mtx);
    213 		buf = child->db.db_data;
    214 		if (buf != NULL && child->db_state != DB_FILL &&
    215 		    child->db_last_dirty == NULL) {
    216 			for (j = 0; j < child->db.db_size >> 3; j++) {
    217 				if (buf[j] != 0) {
    218 					panic("freed data not zero: "
    219 					    "child=%p i=%d off=%d num=%d\n",
    220 					    (void *)child, i, off, num);
    221 				}
    222 			}
    223 		}
    224 		mutex_exit(&child->db_mtx);
    225 
    226 		dbuf_rele(child, FTAG);
    227 	}
    228 	DB_DNODE_EXIT(db);
    229 }
    230 #endif
    231 
    232 static void
    233 free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks,
    234     dmu_tx_t *tx)
    235 {
    236 	dnode_t *dn;
    237 	blkptr_t *bp;
    238 	dmu_buf_impl_t *subdb;
    239 	uint64_t start, end, dbstart, dbend, i;
    240 	int epbs, shift;
    241 
    242 	/*
    243 	 * There is a small possibility that this block will not be cached:
    244 	 *   1 - if level > 1 and there are no children with level <= 1
    245 	 *   2 - if this block was evicted since we read it from
    246 	 *	 dmu_tx_hold_free().
    247 	 */
    248 	if (db->db_state != DB_CACHED)
    249 		(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
    250 
    251 	dbuf_release_bp(db);
    252 	bp = db->db.db_data;
    253 
    254 	DB_DNODE_ENTER(db);
    255 	dn = DB_DNODE(db);
    256 	epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
    257 	shift = (db->db_level - 1) * epbs;
    258 	dbstart = db->db_blkid << epbs;
    259 	start = blkid >> shift;
    260 	if (dbstart < start) {
    261 		bp += start - dbstart;
    262 	} else {
    263 		start = dbstart;
    264 	}
    265 	dbend = ((db->db_blkid + 1) << epbs) - 1;
    266 	end = (blkid + nblks - 1) >> shift;
    267 	if (dbend <= end)
    268 		end = dbend;
    269 
    270 	ASSERT3U(start, <=, end);
    271 
    272 	if (db->db_level == 1) {
    273 		FREE_VERIFY(db, start, end, tx);
    274 		free_blocks(dn, bp, end-start+1, tx);
    275 	} else {
    276 		for (i = start; i <= end; i++, bp++) {
    277 			if (BP_IS_HOLE(bp))
    278 				continue;
    279 			rw_enter(&dn->dn_struct_rwlock, RW_READER);
    280 			VERIFY0(dbuf_hold_impl(dn, db->db_level - 1,
    281 			    i, TRUE, FALSE, FTAG, &subdb));
    282 			rw_exit(&dn->dn_struct_rwlock);
    283 			ASSERT3P(bp, ==, subdb->db_blkptr);
    284 
    285 			free_children(subdb, blkid, nblks, tx);
    286 			dbuf_rele(subdb, FTAG);
    287 		}
    288 	}
    289 
    290 	/* If this whole block is free, free ourself too. */
    291 	for (i = 0, bp = db->db.db_data; i < 1 << epbs; i++, bp++) {
    292 		if (!BP_IS_HOLE(bp))
    293 			break;
    294 	}
    295 	if (i == 1 << epbs) {
    296 		/* didn't find any non-holes */
    297 		bzero(db->db.db_data, db->db.db_size);
    298 		free_blocks(dn, db->db_blkptr, 1, tx);
    299 	} else {
    300 		/*
    301 		 * Partial block free; must be marked dirty so that it
    302 		 * will be written out.
    303 		 */
    304 		ASSERT(db->db_dirtycnt > 0);
    305 	}
    306 
    307 	DB_DNODE_EXIT(db);
    308 	arc_buf_freeze(db->db_buf);
    309 }
    310 
    311 /*
    312  * Traverse the indicated range of the provided file
    313  * and "free" all the blocks contained there.
    314  */
    315 static void
    316 dnode_sync_free_range_impl(dnode_t *dn, uint64_t blkid, uint64_t nblks,
    317     dmu_tx_t *tx)
    318 {
    319 	blkptr_t *bp = dn->dn_phys->dn_blkptr;
    320 	int dnlevel = dn->dn_phys->dn_nlevels;
    321 	boolean_t trunc = B_FALSE;
    322 
    323 	if (blkid > dn->dn_phys->dn_maxblkid)
    324 		return;
    325 
    326 	ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX);
    327 	if (blkid + nblks > dn->dn_phys->dn_maxblkid) {
    328 		nblks = dn->dn_phys->dn_maxblkid - blkid + 1;
    329 		trunc = B_TRUE;
    330 	}
    331 
    332 	/* There are no indirect blocks in the object */
    333 	if (dnlevel == 1) {
    334 		if (blkid >= dn->dn_phys->dn_nblkptr) {
    335 			/* this range was never made persistent */
    336 			return;
    337 		}
    338 		ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);
    339 		free_blocks(dn, bp + blkid, nblks, tx);
    340 	} else {
    341 		int shift = (dnlevel - 1) *
    342 		    (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT);
    343 		int start = blkid >> shift;
    344 		int end = (blkid + nblks - 1) >> shift;
    345 		dmu_buf_impl_t *db;
    346 
    347 		ASSERT(start < dn->dn_phys->dn_nblkptr);
    348 		bp += start;
    349 		for (int i = start; i <= end; i++, bp++) {
    350 			if (BP_IS_HOLE(bp))
    351 				continue;
    352 			rw_enter(&dn->dn_struct_rwlock, RW_READER);
    353 			VERIFY0(dbuf_hold_impl(dn, dnlevel - 1, i,
    354 			    TRUE, FALSE, FTAG, &db));
    355 			rw_exit(&dn->dn_struct_rwlock);
    356 
    357 			free_children(db, blkid, nblks, tx);
    358 			dbuf_rele(db, FTAG);
    359 		}
    360 	}
    361 
    362 	if (trunc) {
    363 		dn->dn_phys->dn_maxblkid = blkid == 0 ? 0 : blkid - 1;
    364 
    365 		uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *
    366 		    (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
    367 		ASSERT(off < dn->dn_phys->dn_maxblkid ||
    368 		    dn->dn_phys->dn_maxblkid == 0 ||
    369 		    dnode_next_offset(dn, 0, &off, 1, 1, 0) != 0);
    370 	}
    371 }
    372 
    373 typedef struct dnode_sync_free_range_arg {
    374 	dnode_t *dsfra_dnode;
    375 	dmu_tx_t *dsfra_tx;
    376 } dnode_sync_free_range_arg_t;
    377 
    378 static void
    379 dnode_sync_free_range(void *arg, uint64_t blkid, uint64_t nblks)
    380 {
    381 	dnode_sync_free_range_arg_t *dsfra = arg;
    382 	dnode_t *dn = dsfra->dsfra_dnode;
    383 
    384 	mutex_exit(&dn->dn_mtx);
    385 	dnode_sync_free_range_impl(dn, blkid, nblks, dsfra->dsfra_tx);
    386 	mutex_enter(&dn->dn_mtx);
    387 }
    388 
    389 /*
    390  * Try to kick all the dnode's dbufs out of the cache...
    391  */
    392 void
    393 dnode_evict_dbufs(dnode_t *dn)
    394 {
    395 	dmu_buf_impl_t db_marker;
    396 	dmu_buf_impl_t *db, *db_next;
    397 
    398 	mutex_enter(&dn->dn_dbufs_mtx);
    399 	for (db = avl_first(&dn->dn_dbufs); db != NULL; db = db_next) {
    400 
    401 #ifdef	DEBUG
    402 		DB_DNODE_ENTER(db);
    403 		ASSERT3P(DB_DNODE(db), ==, dn);
    404 		DB_DNODE_EXIT(db);
    405 #endif	/* DEBUG */
    406 
    407 		mutex_enter(&db->db_mtx);
    408 		if (db->db_state != DB_EVICTING &&
    409 		    refcount_is_zero(&db->db_holds)) {
    410 			db_marker.db_level = db->db_level;
    411 			db_marker.db_blkid = db->db_blkid;
    412 			db_marker.db_state = DB_SEARCH;
    413 			avl_insert_here(&dn->dn_dbufs, &db_marker, db,
    414 			    AVL_BEFORE);
    415 
    416 			dbuf_destroy(db);
    417 
    418 			db_next = AVL_NEXT(&dn->dn_dbufs, &db_marker);
    419 			avl_remove(&dn->dn_dbufs, &db_marker);
    420 		} else {
    421 			db->db_pending_evict = TRUE;
    422 			mutex_exit(&db->db_mtx);
    423 			db_next = AVL_NEXT(&dn->dn_dbufs, db);
    424 		}
    425 	}
    426 	mutex_exit(&dn->dn_dbufs_mtx);
    427 
    428 	dnode_evict_bonus(dn);
    429 }
    430 
    431 void
    432 dnode_evict_bonus(dnode_t *dn)
    433 {
    434 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
    435 	if (dn->dn_bonus != NULL) {
    436 		if (refcount_is_zero(&dn->dn_bonus->db_holds)) {
    437 			mutex_enter(&dn->dn_bonus->db_mtx);
    438 			dbuf_destroy(dn->dn_bonus);
    439 			dn->dn_bonus = NULL;
    440 		} else {
    441 			dn->dn_bonus->db_pending_evict = TRUE;
    442 		}
    443 	}
    444 	rw_exit(&dn->dn_struct_rwlock);
    445 }
    446 
    447 static void
    448 dnode_undirty_dbufs(list_t *list)
    449 {
    450 	dbuf_dirty_record_t *dr;
    451 
    452 	while (dr = list_head(list)) {
    453 		dmu_buf_impl_t *db = dr->dr_dbuf;
    454 		uint64_t txg = dr->dr_txg;
    455 
    456 		if (db->db_level != 0)
    457 			dnode_undirty_dbufs(&dr->dt.di.dr_children);
    458 
    459 		mutex_enter(&db->db_mtx);
    460 		/* XXX - use dbuf_undirty()? */
    461 		list_remove(list, dr);
    462 		ASSERT(db->db_last_dirty == dr);
    463 		db->db_last_dirty = NULL;
    464 		db->db_dirtycnt -= 1;
    465 		if (db->db_level == 0) {
    466 			ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
    467 			    dr->dt.dl.dr_data == db->db_buf);
    468 			dbuf_unoverride(dr);
    469 		} else {
    470 			mutex_destroy(&dr->dt.di.dr_mtx);
    471 			list_destroy(&dr->dt.di.dr_children);
    472 		}
    473 		kmem_free(dr, sizeof (dbuf_dirty_record_t));
    474 		dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
    475 	}
    476 }
    477 
    478 static void
    479 dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
    480 {
    481 	int txgoff = tx->tx_txg & TXG_MASK;
    482 
    483 	ASSERT(dmu_tx_is_syncing(tx));
    484 
    485 	/*
    486 	 * Our contents should have been freed in dnode_sync() by the
    487 	 * free range record inserted by the caller of dnode_free().
    488 	 */
    489 	ASSERT0(DN_USED_BYTES(dn->dn_phys));
    490 	ASSERT(BP_IS_HOLE(dn->dn_phys->dn_blkptr));
    491 
    492 	dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
    493 	dnode_evict_dbufs(dn);
    494 
    495 	/*
    496 	 * XXX - It would be nice to assert this, but we may still
    497 	 * have residual holds from async evictions from the arc...
    498 	 *
    499 	 * zfs_obj_to_path() also depends on this being
    500 	 * commented out.
    501 	 *
    502 	 * ASSERT3U(refcount_count(&dn->dn_holds), ==, 1);
    503 	 */
    504 
    505 	/* Undirty next bits */
    506 	dn->dn_next_nlevels[txgoff] = 0;
    507 	dn->dn_next_indblkshift[txgoff] = 0;
    508 	dn->dn_next_blksz[txgoff] = 0;
    509 
    510 	/* ASSERT(blkptrs are zero); */
    511 	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
    512 	ASSERT(dn->dn_type != DMU_OT_NONE);
    513 
    514 	ASSERT(dn->dn_free_txg > 0);
    515 	if (dn->dn_allocated_txg != dn->dn_free_txg)
    516 		dmu_buf_will_dirty(&dn->dn_dbuf->db, tx);
    517 	bzero(dn->dn_phys, sizeof (dnode_phys_t));
    518 
    519 	mutex_enter(&dn->dn_mtx);
    520 	dn->dn_type = DMU_OT_NONE;
    521 	dn->dn_maxblkid = 0;
    522 	dn->dn_allocated_txg = 0;
    523 	dn->dn_free_txg = 0;
    524 	dn->dn_have_spill = B_FALSE;
    525 	mutex_exit(&dn->dn_mtx);
    526 
    527 	ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
    528 
    529 	dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
    530 	/*
    531 	 * Now that we've released our hold, the dnode may
    532 	 * be evicted, so we musn't access it.
    533 	 */
    534 }
    535 
    536 /*
    537  * Write out the dnode's dirty buffers.
    538  */
    539 void
    540 dnode_sync(dnode_t *dn, dmu_tx_t *tx)
    541 {
    542 	dnode_phys_t *dnp = dn->dn_phys;
    543 	int txgoff = tx->tx_txg & TXG_MASK;
    544 	list_t *list = &dn->dn_dirty_records[txgoff];
    545 	static const dnode_phys_t zerodn = { 0 };
    546 	boolean_t kill_spill = B_FALSE;
    547 
    548 	ASSERT(dmu_tx_is_syncing(tx));
    549 	ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg);
    550 	ASSERT(dnp->dn_type != DMU_OT_NONE ||
    551 	    bcmp(dnp, &zerodn, DNODE_SIZE) == 0);
    552 	DNODE_VERIFY(dn);
    553 
    554 	ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf));
    555 
    556 	if (dmu_objset_userused_enabled(dn->dn_objset) &&
    557 	    !DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
    558 		mutex_enter(&dn->dn_mtx);
    559 		dn->dn_oldused = DN_USED_BYTES(dn->dn_phys);
    560 		dn->dn_oldflags = dn->dn_phys->dn_flags;
    561 		dn->dn_phys->dn_flags |= DNODE_FLAG_USERUSED_ACCOUNTED;
    562 		mutex_exit(&dn->dn_mtx);
    563 		dmu_objset_userquota_get_ids(dn, B_FALSE, tx);
    564 	} else {
    565 		/* Once we account for it, we should always account for it. */
    566 		ASSERT(!(dn->dn_phys->dn_flags &
    567 		    DNODE_FLAG_USERUSED_ACCOUNTED));
    568 	}
    569 
    570 	mutex_enter(&dn->dn_mtx);
    571 	if (dn->dn_allocated_txg == tx->tx_txg) {
    572 		/* The dnode is newly allocated or reallocated */
    573 		if (dnp->dn_type == DMU_OT_NONE) {
    574 			/* this is a first alloc, not a realloc */
    575 			dnp->dn_nlevels = 1;
    576 			dnp->dn_nblkptr = dn->dn_nblkptr;
    577 		}
    578 
    579 		dnp->dn_type = dn->dn_type;
    580 		dnp->dn_bonustype = dn->dn_bonustype;
    581 		dnp->dn_bonuslen = dn->dn_bonuslen;
    582 	}
    583 	ASSERT(dnp->dn_nlevels > 1 ||
    584 	    BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
    585 	    BP_IS_EMBEDDED(&dnp->dn_blkptr[0]) ||
    586 	    BP_GET_LSIZE(&dnp->dn_blkptr[0]) ==
    587 	    dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
    588 	ASSERT(dnp->dn_nlevels < 2 ||
    589 	    BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
    590 	    BP_GET_LSIZE(&dnp->dn_blkptr[0]) == 1 << dnp->dn_indblkshift);
    591 
    592 	if (dn->dn_next_type[txgoff] != 0) {
    593 		dnp->dn_type = dn->dn_type;
    594 		dn->dn_next_type[txgoff] = 0;
    595 	}
    596 
    597 	if (dn->dn_next_blksz[txgoff] != 0) {
    598 		ASSERT(P2PHASE(dn->dn_next_blksz[txgoff],
    599 		    SPA_MINBLOCKSIZE) == 0);
    600 		ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
    601 		    dn->dn_maxblkid == 0 || list_head(list) != NULL ||
    602 		    dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT ==
    603 		    dnp->dn_datablkszsec ||
    604 		    range_tree_space(dn->dn_free_ranges[txgoff]) != 0);
    605 		dnp->dn_datablkszsec =
    606 		    dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT;
    607 		dn->dn_next_blksz[txgoff] = 0;
    608 	}
    609 
    610 	if (dn->dn_next_bonuslen[txgoff] != 0) {
    611 		if (dn->dn_next_bonuslen[txgoff] == DN_ZERO_BONUSLEN)
    612 			dnp->dn_bonuslen = 0;
    613 		else
    614 			dnp->dn_bonuslen = dn->dn_next_bonuslen[txgoff];
    615 		ASSERT(dnp->dn_bonuslen <= DN_MAX_BONUSLEN);
    616 		dn->dn_next_bonuslen[txgoff] = 0;
    617 	}
    618 
    619 	if (dn->dn_next_bonustype[txgoff] != 0) {
    620 		ASSERT(DMU_OT_IS_VALID(dn->dn_next_bonustype[txgoff]));
    621 		dnp->dn_bonustype = dn->dn_next_bonustype[txgoff];
    622 		dn->dn_next_bonustype[txgoff] = 0;
    623 	}
    624 
    625 	boolean_t freeing_dnode = dn->dn_free_txg > 0 &&
    626 	    dn->dn_free_txg <= tx->tx_txg;
    627 
    628 	/*
    629 	 * Remove the spill block if we have been explicitly asked to
    630 	 * remove it, or if the object is being removed.
    631 	 */
    632 	if (dn->dn_rm_spillblk[txgoff] || freeing_dnode) {
    633 		if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)
    634 			kill_spill = B_TRUE;
    635 		dn->dn_rm_spillblk[txgoff] = 0;
    636 	}
    637 
    638 	if (dn->dn_next_indblkshift[txgoff] != 0) {
    639 		ASSERT(dnp->dn_nlevels == 1);
    640 		dnp->dn_indblkshift = dn->dn_next_indblkshift[txgoff];
    641 		dn->dn_next_indblkshift[txgoff] = 0;
    642 	}
    643 
    644 	/*
    645 	 * Just take the live (open-context) values for checksum and compress.
    646 	 * Strictly speaking it's a future leak, but nothing bad happens if we
    647 	 * start using the new checksum or compress algorithm a little early.
    648 	 */
    649 	dnp->dn_checksum = dn->dn_checksum;
    650 	dnp->dn_compress = dn->dn_compress;
    651 
    652 	mutex_exit(&dn->dn_mtx);
    653 
    654 	if (kill_spill) {
    655 		free_blocks(dn, &dn->dn_phys->dn_spill, 1, tx);
    656 		mutex_enter(&dn->dn_mtx);
    657 		dnp->dn_flags &= ~DNODE_FLAG_SPILL_BLKPTR;
    658 		mutex_exit(&dn->dn_mtx);
    659 	}
    660 
    661 	/* process all the "freed" ranges in the file */
    662 	if (dn->dn_free_ranges[txgoff] != NULL) {
    663 		dnode_sync_free_range_arg_t dsfra;
    664 		dsfra.dsfra_dnode = dn;
    665 		dsfra.dsfra_tx = tx;
    666 		mutex_enter(&dn->dn_mtx);
    667 		range_tree_vacate(dn->dn_free_ranges[txgoff],
    668 		    dnode_sync_free_range, &dsfra);
    669 		range_tree_destroy(dn->dn_free_ranges[txgoff]);
    670 		dn->dn_free_ranges[txgoff] = NULL;
    671 		mutex_exit(&dn->dn_mtx);
    672 	}
    673 
    674 	if (freeing_dnode) {
    675 		dnode_sync_free(dn, tx);
    676 		return;
    677 	}
    678 
    679 	if (dn->dn_next_nlevels[txgoff]) {
    680 		dnode_increase_indirection(dn, tx);
    681 		dn->dn_next_nlevels[txgoff] = 0;
    682 	}
    683 
    684 	if (dn->dn_next_nblkptr[txgoff]) {
    685 		/* this should only happen on a realloc */
    686 		ASSERT(dn->dn_allocated_txg == tx->tx_txg);
    687 		if (dn->dn_next_nblkptr[txgoff] > dnp->dn_nblkptr) {
    688 			/* zero the new blkptrs we are gaining */
    689 			bzero(dnp->dn_blkptr + dnp->dn_nblkptr,
    690 			    sizeof (blkptr_t) *
    691 			    (dn->dn_next_nblkptr[txgoff] - dnp->dn_nblkptr));
    692 #ifdef notyet /* XXX: gcc-9 */
    693 #ifdef ZFS_DEBUG
    694 		} else {
    695 			int i;
    696 			ASSERT(dn->dn_next_nblkptr[txgoff] < dnp->dn_nblkptr);
    697 			/* the blkptrs we are losing better be unallocated */
    698 			for (i = dn->dn_next_nblkptr[txgoff];
    699 			    i < dnp->dn_nblkptr; i++)
    700 				ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[i]));
    701 #endif
    702 #endif
    703 		}
    704 		mutex_enter(&dn->dn_mtx);
    705 		dnp->dn_nblkptr = dn->dn_next_nblkptr[txgoff];
    706 		dn->dn_next_nblkptr[txgoff] = 0;
    707 		mutex_exit(&dn->dn_mtx);
    708 	}
    709 
    710 	dbuf_sync_list(list, dn->dn_phys->dn_nlevels - 1, tx);
    711 
    712 	if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
    713 		ASSERT3P(list_head(list), ==, NULL);
    714 		dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
    715 	}
    716 
    717 	/*
    718 	 * Although we have dropped our reference to the dnode, it
    719 	 * can't be evicted until its written, and we haven't yet
    720 	 * initiated the IO for the dnode's dbuf.
    721 	 */
    722 }
    723