sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dnode_sync.c

   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  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include <sys/zfs_context.h>
  27 #include <sys/dbuf.h>
  28 #include <sys/dnode.h>
  29 #include <sys/dmu.h>
  30 #include <sys/dmu_tx.h>
  31 #include <sys/dmu_objset.h>
  32 #include <sys/dsl_dataset.h>
  33 #include <sys/spa.h>
  34
  35 static void
  36 dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
  37 {
  38         dmu_buf_impl_t *db;
  39         int txgoff = tx->tx_txg & TXG_MASK;
  40         int nblkptr = dn->dn_phys->dn_nblkptr;
  41         int old_toplvl = dn->dn_phys->dn_nlevels - 1;
  42         int new_level = dn->dn_next_nlevels[txgoff];
  43         int i;
  44
  45         rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
  46
  47         /* this dnode can't be paged out because it's dirty */
  48         ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
  49         ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
  50         ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);
  51
  52         db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
  53         ASSERT(db != NULL);
  54
  55         dn->dn_phys->dn_nlevels = new_level;
  56         dprintf("os=%p obj=%llu, increase to %d\n", dn->dn_objset,
  57             dn->dn_object, dn->dn_phys->dn_nlevels);
  58
  59         /* check for existing blkptrs in the dnode */
  60         for (i = 0; i < nblkptr; i++)
  61                 if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[i]))
  62                         break;
  63         if (i != nblkptr) {
  64                 /* transfer dnode's block pointers to new indirect block */
  65                 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
  66                 ASSERT(db->db.db_data);
  67                 ASSERT(arc_released(db->db_buf));
  68                 ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
  69                 bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,
  70                     sizeof (blkptr_t) * nblkptr);
  71                 arc_buf_freeze(db->db_buf);
  72         }
  73
  74         /* set dbuf's parent pointers to new indirect buf */
  75         for (i = 0; i < nblkptr; i++) {
  76                 dmu_buf_impl_t *child = dbuf_find(dn, old_toplvl, i);
  77
  78                 if (child == NULL)
  79                         continue;
  80                 ASSERT3P(child->db_dnode, ==, dn);
  81                 if (child->db_parent && child->db_parent != dn->dn_dbuf) {
  82                         ASSERT(child->db_parent->db_level == db->db_level);
  83                         ASSERT(child->db_blkptr !=
  84                             &dn->dn_phys->dn_blkptr[child->db_blkid]);
  85                         mutex_exit(&child->db_mtx);
  86                         continue;
  87                 }
  88                 ASSERT(child->db_parent == NULL ||
  89                     child->db_parent == dn->dn_dbuf);
  90
  91                 child->db_parent = db;
  92                 dbuf_add_ref(db, child);
  93                 if (db->db.db_data)
  94                         child->db_blkptr = (blkptr_t *)db->db.db_data + i;
  95                 else
  96                         child->db_blkptr = NULL;
  97                 dprintf_dbuf_bp(child, child->db_blkptr,
  98                     "changed db_blkptr to new indirect %s", "");
  99
 100                 mutex_exit(&child->db_mtx);
 101         }
 102
 103         bzero(dn->dn_phys->dn_blkptr, sizeof (blkptr_t) * nblkptr);
 104
 105         dbuf_rele(db, FTAG);
 106
 107         rw_exit(&dn->dn_struct_rwlock);
 108 }
 109
 110 static int
 111 free_blocks(dnode_t *dn, blkptr_t *bp, int num, dmu_tx_t *tx)
 112 {
 113         dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
 114         uint64_t bytesfreed = 0;
 115         int i, blocks_freed = 0;
 116
 117         dprintf("ds=%p obj=%llx num=%d\n", ds, dn->dn_object, num);
 118
 119         for (i = 0; i < num; i++, bp++) {
 120                 if (BP_IS_HOLE(bp))
 121                         continue;
 122
 123                 bytesfreed += dsl_dataset_block_kill(ds, bp, dn->dn_zio, tx);
 124                 ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));
 125                 bzero(bp, sizeof (blkptr_t));
 126                 blocks_freed += 1;
 127         }
 128         dnode_diduse_space(dn, -bytesfreed);
 129         return (blocks_freed);
 130 }
 131
 132 #ifdef ZFS_DEBUG
 133 static void
 134 free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
 135 {
 136         int off, num;
 137         int i, err, epbs;
 138         uint64_t txg = tx->tx_txg;
 139
 140         epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
 141         off = start - (db->db_blkid * 1<<epbs);
 142         num = end - start + 1;
 143
 144         ASSERT3U(off, >=, 0);
 145         ASSERT3U(num, >=, 0);
 146         ASSERT3U(db->db_level, >, 0);
 147         ASSERT3U(db->db.db_size, ==, 1<<db->db_dnode->dn_phys->dn_indblkshift);
 148         ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT);
 149         ASSERT(db->db_blkptr != NULL);
 150
 151         for (i = off; i < off+num; i++) {
 152                 uint64_t *buf;
 153                 dmu_buf_impl_t *child;
 154                 dbuf_dirty_record_t *dr;
 155                 int j;
 156
 157                 ASSERT(db->db_level == 1);
 158
 159                 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);
 160                 err = dbuf_hold_impl(db->db_dnode, db->db_level-1,
 161                     (db->db_blkid << epbs) + i, TRUE, FTAG, &child);
 162                 rw_exit(&db->db_dnode->dn_struct_rwlock);
 163                 if (err == ENOENT)
 164                         continue;
 165                 ASSERT(err == 0);
 166                 ASSERT(child->db_level == 0);
 167                 dr = child->db_last_dirty;
 168                 while (dr && dr->dr_txg > txg)
 169                         dr = dr->dr_next;
 170                 ASSERT(dr == NULL || dr->dr_txg == txg);
 171
 172                 /* data_old better be zeroed */
 173                 if (dr) {
 174                         buf = dr->dt.dl.dr_data->b_data;
 175                         for (j = 0; j < child->db.db_size >> 3; j++) {
 176                                 if (buf[j] != 0) {
 177                                         panic("freed data not zero: "
 178                                             "child=%p i=%d off=%d num=%d\n",
 179                                             (void *)child, i, off, num);
 180                                 }
 181                         }
 182                 }
 183
 184                 /*
 185                  * db_data better be zeroed unless it's dirty in a
 186                  * future txg.
 187                  */
 188                 mutex_enter(&child->db_mtx);
 189                 buf = child->db.db_data;
 190                 if (buf != NULL && child->db_state != DB_FILL &&
 191                     child->db_last_dirty == NULL) {
 192                         for (j = 0; j < child->db.db_size >> 3; j++) {
 193                                 if (buf[j] != 0) {
 194                                         panic("freed data not zero: "
 195                                             "child=%p i=%d off=%d num=%d\n",
 196                                             (void *)child, i, off, num);
 197                                 }
 198                         }
 199                 }
 200                 mutex_exit(&child->db_mtx);
 201
 202                 dbuf_rele(child, FTAG);
 203         }
 204 }
 205 #endif
 206
 207 #define ALL -1
 208
 209 static int
 210 free_children(dmu_buf_impl_t *db, uint64_t blkid, uint64_t nblks, int trunc,
 211     dmu_tx_t *tx)
 212 {
 213         dnode_t *dn = db->db_dnode;
 214         blkptr_t *bp;
 215         dmu_buf_impl_t *subdb;
 216         uint64_t start, end, dbstart, dbend, i;
 217         int epbs, shift, err;
 218         int all = TRUE;
 219         int blocks_freed = 0;
 220
 221         /*
 222          * There is a small possibility that this block will not be cached:
 223          *   1 - if level > 1 and there are no children with level <= 1
 224          *   2 - if we didn't get a dirty hold (because this block had just
 225          *       finished being written -- and so had no holds), and then this
 226          *       block got evicted before we got here.
 227          */
 228         if (db->db_state != DB_CACHED)
 229                 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
 230
 231         arc_release(db->db_buf, db);
 232         bp = (blkptr_t *)db->db.db_data;
 233
 234         epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
 235         shift = (db->db_level - 1) * epbs;
 236         dbstart = db->db_blkid << epbs;
 237         start = blkid >> shift;
 238         if (dbstart < start) {
 239                 bp += start - dbstart;
 240                 all = FALSE;
 241         } else {
 242                 start = dbstart;
 243         }
 244         dbend = ((db->db_blkid + 1) << epbs) - 1;
 245         end = (blkid + nblks - 1) >> shift;
 246         if (dbend <= end)
 247                 end = dbend;
 248         else if (all)
 249                 all = trunc;
 250         ASSERT3U(start, <=, end);
 251
 252         if (db->db_level == 1) {
 253                 FREE_VERIFY(db, start, end, tx);
 254                 blocks_freed = free_blocks(dn, bp, end-start+1, tx);
 255                 arc_buf_freeze(db->db_buf);
 256                 ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
 257                 return (all ? ALL : blocks_freed);
 258         }
 259
 260         for (i = start; i <= end; i++, bp++) {
 261                 if (BP_IS_HOLE(bp))
 262                         continue;
 263                 rw_enter(&dn->dn_struct_rwlock, RW_READER);
 264                 err = dbuf_hold_impl(dn, db->db_level-1, i, TRUE, FTAG, &subdb);
 265                 ASSERT3U(err, ==, 0);
 266                 rw_exit(&dn->dn_struct_rwlock);
 267
 268                 if (free_children(subdb, blkid, nblks, trunc, tx) == ALL) {
 269                         ASSERT3P(subdb->db_blkptr, ==, bp);
 270                         blocks_freed += free_blocks(dn, bp, 1, tx);
 271                 } else {
 272                         all = FALSE;
 273                 }
 274                 dbuf_rele(subdb, FTAG);
 275         }
 276         arc_buf_freeze(db->db_buf);
 277 #ifdef ZFS_DEBUG
 278         bp -= (end-start)+1;
 279         for (i = start; i <= end; i++, bp++) {
 280                 if (i == start && blkid != 0)
 281                         continue;
 282                 else if (i == end && !trunc)
 283                         continue;
 284                 ASSERT3U(bp->blk_birth, ==, 0);
 285         }
 286 #endif
 287         ASSERT(all || blocks_freed == 0 || db->db_last_dirty);
 288         return (all ? ALL : blocks_freed);
 289 }
 290
 291 /*
 292  * free_range: Traverse the indicated range of the provided file
 293  * and "free" all the blocks contained there.
 294  */
 295 static void
 296 dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
 297 {
 298         blkptr_t *bp = dn->dn_phys->dn_blkptr;
 299         dmu_buf_impl_t *db;
 300         int trunc, start, end, shift, i, err;
 301         int dnlevel = dn->dn_phys->dn_nlevels;
 302
 303         if (blkid > dn->dn_phys->dn_maxblkid)
 304                 return;
 305
 306         ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX);
 307         trunc = blkid + nblks > dn->dn_phys->dn_maxblkid;
 308         if (trunc)
 309                 nblks = dn->dn_phys->dn_maxblkid - blkid + 1;
 310
 311         /* There are no indirect blocks in the object */
 312         if (dnlevel == 1) {
 313                 if (blkid >= dn->dn_phys->dn_nblkptr) {
 314                         /* this range was never made persistent */
 315                         return;
 316                 }
 317                 ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);
 318                 (void) free_blocks(dn, bp + blkid, nblks, tx);
 319                 if (trunc) {
 320                         uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *
 321                             (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 322                         dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);
 323                         ASSERT(off < dn->dn_phys->dn_maxblkid ||
 324                             dn->dn_phys->dn_maxblkid == 0 ||
 325                             dnode_next_offset(dn, 0, &off, 1, 1, 0) != 0);
 326                 }
 327                 return;
 328         }
 329
 330         shift = (dnlevel - 1) * (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT);
 331         start = blkid >> shift;
 332         ASSERT(start < dn->dn_phys->dn_nblkptr);
 333         end = (blkid + nblks - 1) >> shift;
 334         bp += start;
 335         for (i = start; i <= end; i++, bp++) {
 336                 if (BP_IS_HOLE(bp))
 337                         continue;
 338                 rw_enter(&dn->dn_struct_rwlock, RW_READER);
 339                 err = dbuf_hold_impl(dn, dnlevel-1, i, TRUE, FTAG, &db);
 340                 ASSERT3U(err, ==, 0);
 341                 rw_exit(&dn->dn_struct_rwlock);
 342
 343                 if (free_children(db, blkid, nblks, trunc, tx) == ALL) {
 344                         ASSERT3P(db->db_blkptr, ==, bp);
 345                         (void) free_blocks(dn, bp, 1, tx);
 346                 }
 347                 dbuf_rele(db, FTAG);
 348         }
 349         if (trunc) {
 350                 uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *
 351                     (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 352                 dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);
 353                 ASSERT(off < dn->dn_phys->dn_maxblkid ||
 354                     dn->dn_phys->dn_maxblkid == 0 ||
 355                     dnode_next_offset(dn, 0, &off, 1, 1, 0) != 0);
 356         }
 357 }
 358
 359 /*
 360  * Try to kick all the dnodes dbufs out of the cache...
 361  */
 362 void
 363 dnode_evict_dbufs(dnode_t *dn)
 364 {
 365         int progress;
 366         int pass = 0;
 367
 368         do {
 369                 dmu_buf_impl_t *db, marker;
 370                 int evicting = FALSE;
 371
 372                 progress = FALSE;
 373                 mutex_enter(&dn->dn_dbufs_mtx);
 374                 list_insert_tail(&dn->dn_dbufs, &marker);
 375                 db = list_head(&dn->dn_dbufs);
 376                 for (; db != &marker; db = list_head(&dn->dn_dbufs)) {
 377                         list_remove(&dn->dn_dbufs, db);
 378                         list_insert_tail(&dn->dn_dbufs, db);
 379                         ASSERT3P(db->db_dnode, ==, dn);
 380
 381                         mutex_enter(&db->db_mtx);
 382                         if (db->db_state == DB_EVICTING) {
 383                                 progress = TRUE;
 384                                 evicting = TRUE;
 385                                 mutex_exit(&db->db_mtx);
 386                         } else if (refcount_is_zero(&db->db_holds)) {
 387                                 progress = TRUE;
 388                                 dbuf_clear(db); /* exits db_mtx for us */
 389                         } else {
 390                                 mutex_exit(&db->db_mtx);
 391                         }
 392
 393                 }
 394                 list_remove(&dn->dn_dbufs, &marker);
 395                 /*
 396                  * NB: we need to drop dn_dbufs_mtx between passes so
 397                  * that any DB_EVICTING dbufs can make progress.
 398                  * Ideally, we would have some cv we could wait on, but
 399                  * since we don't, just wait a bit to give the other
 400                  * thread a chance to run.
 401                  */
 402                 mutex_exit(&dn->dn_dbufs_mtx);
 403                 if (evicting)
 404                         delay(1);
 405                 pass++;
 406                 ASSERT(pass < 100); /* sanity check */
 407         } while (progress);
 408
 409         rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
 410         if (dn->dn_bonus && refcount_is_zero(&dn->dn_bonus->db_holds)) {
 411                 mutex_enter(&dn->dn_bonus->db_mtx);
 412                 dbuf_evict(dn->dn_bonus);
 413                 dn->dn_bonus = NULL;
 414         }
 415         rw_exit(&dn->dn_struct_rwlock);
 416 }
 417
 418 static void
 419 dnode_undirty_dbufs(list_t *list)
 420 {
 421         dbuf_dirty_record_t *dr;
 422
 423         while (dr = list_head(list)) {
 424                 dmu_buf_impl_t *db = dr->dr_dbuf;
 425                 uint64_t txg = dr->dr_txg;
 426
 427                 mutex_enter(&db->db_mtx);
 428                 /* XXX - use dbuf_undirty()? */
 429                 list_remove(list, dr);
 430                 ASSERT(db->db_last_dirty == dr);
 431                 db->db_last_dirty = NULL;
 432                 db->db_dirtycnt -= 1;
 433                 if (db->db_level == 0) {
 434                         ASSERT(db->db_blkid == DB_BONUS_BLKID ||
 435                             dr->dt.dl.dr_data == db->db_buf);
 436                         dbuf_unoverride(dr);
 437                         mutex_exit(&db->db_mtx);
 438                 } else {
 439                         mutex_exit(&db->db_mtx);
 440                         dnode_undirty_dbufs(&dr->dt.di.dr_children);
 441                         list_destroy(&dr->dt.di.dr_children);
 442                         mutex_destroy(&dr->dt.di.dr_mtx);
 443                 }
 444                 kmem_free(dr, sizeof (dbuf_dirty_record_t));
 445                 dbuf_rele(db, (void *)(uintptr_t)txg);
 446         }
 447 }
 448
 449 static void
 450 dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
 451 {
 452         int txgoff = tx->tx_txg & TXG_MASK;
 453
 454         ASSERT(dmu_tx_is_syncing(tx));
 455
 456         /*
 457          * Our contents should have been freed in dnode_sync() by the
 458          * free range record inserted by the caller of dnode_free().
 459          */
 460         ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0);
 461         ASSERT(BP_IS_HOLE(dn->dn_phys->dn_blkptr));
 462
 463         dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
 464         dnode_evict_dbufs(dn);
 465         ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
 466
 467         /*
 468          * XXX - It would be nice to assert this, but we may still
 469          * have residual holds from async evictions from the arc...
 470          *
 471          * zfs_obj_to_path() also depends on this being
 472          * commented out.
 473          *
 474          * ASSERT3U(refcount_count(&dn->dn_holds), ==, 1);
 475          */
 476
 477         /* Undirty next bits */
 478         dn->dn_next_nlevels[txgoff] = 0;
 479         dn->dn_next_indblkshift[txgoff] = 0;
 480         dn->dn_next_blksz[txgoff] = 0;
 481
 482         /* ASSERT(blkptrs are zero); */
 483         ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
 484         ASSERT(dn->dn_type != DMU_OT_NONE);
 485
 486         ASSERT(dn->dn_free_txg > 0);
 487         if (dn->dn_allocated_txg != dn->dn_free_txg)
 488                 dbuf_will_dirty(dn->dn_dbuf, tx);
 489         bzero(dn->dn_phys, sizeof (dnode_phys_t));
 490
 491         mutex_enter(&dn->dn_mtx);
 492         dn->dn_type = DMU_OT_NONE;
 493         dn->dn_maxblkid = 0;
 494         dn->dn_allocated_txg = 0;
 495         dn->dn_free_txg = 0;
 496         mutex_exit(&dn->dn_mtx);
 497
 498         ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
 499
 500         dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
 501         /*
 502          * Now that we've released our hold, the dnode may
 503          * be evicted, so we musn't access it.
 504          */
 505 }
 506
 507 /*
 508  * Write out the dnode's dirty buffers.
 509  *
 510  * NOTE: The dnode is kept in memory by being dirty.  Once the
 511  * dirty bit is cleared, it may be evicted.  Beware of this!
 512  */
 513 void
 514 dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 515 {
 516         free_range_t *rp;
 517         dnode_phys_t *dnp = dn->dn_phys;
 518         int txgoff = tx->tx_txg & TXG_MASK;
 519         list_t *list = &dn->dn_dirty_records[txgoff];
 520
 521         ASSERT(dmu_tx_is_syncing(tx));
 522         ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg);
 523         DNODE_VERIFY(dn);
 524
 525         ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf));
 526
 527         mutex_enter(&dn->dn_mtx);
 528         if (dn->dn_allocated_txg == tx->tx_txg) {
 529                 /* The dnode is newly allocated or reallocated */
 530                 if (dnp->dn_type == DMU_OT_NONE) {
 531                         /* this is a first alloc, not a realloc */
 532                         /* XXX shouldn't the phys already be zeroed? */
 533                         bzero(dnp, DNODE_CORE_SIZE);
 534                         dnp->dn_nlevels = 1;
 535                         dnp->dn_nblkptr = dn->dn_nblkptr;
 536                 }
 537
 538                 dnp->dn_type = dn->dn_type;
 539                 dnp->dn_bonustype = dn->dn_bonustype;
 540                 dnp->dn_bonuslen = dn->dn_bonuslen;
 541         }
 542
 543         ASSERT(dnp->dn_nlevels > 1 ||
 544             BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
 545             BP_GET_LSIZE(&dnp->dn_blkptr[0]) ==
 546             dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 547
 548         if (dn->dn_next_blksz[txgoff]) {
 549                 ASSERT(P2PHASE(dn->dn_next_blksz[txgoff],
 550                     SPA_MINBLOCKSIZE) == 0);
 551                 ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
 552                     dn->dn_maxblkid == 0 || list_head(list) != NULL ||
 553                     dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT ==
 554                     dnp->dn_datablkszsec);
 555                 dnp->dn_datablkszsec =
 556                     dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT;
 557                 dn->dn_next_blksz[txgoff] = 0;
 558         }
 559
 560         if (dn->dn_next_bonuslen[txgoff]) {
 561                 if (dn->dn_next_bonuslen[txgoff] == DN_ZERO_BONUSLEN)
 562                         dnp->dn_bonuslen = 0;
 563                 else
 564                         dnp->dn_bonuslen = dn->dn_next_bonuslen[txgoff];
 565                 ASSERT(dnp->dn_bonuslen <= DN_MAX_BONUSLEN);
 566                 dn->dn_next_bonuslen[txgoff] = 0;
 567         }
 568
 569         if (dn->dn_next_indblkshift[txgoff]) {
 570                 ASSERT(dnp->dn_nlevels == 1);
 571                 dnp->dn_indblkshift = dn->dn_next_indblkshift[txgoff];
 572                 dn->dn_next_indblkshift[txgoff] = 0;
 573         }
 574
 575         /*
 576          * Just take the live (open-context) values for checksum and compress.
 577          * Strictly speaking it's a future leak, but nothing bad happens if we
 578          * start using the new checksum or compress algorithm a little early.
 579          */
 580         dnp->dn_checksum = dn->dn_checksum;
 581         dnp->dn_compress = dn->dn_compress;
 582
 583         mutex_exit(&dn->dn_mtx);
 584
 585         /* process all the "freed" ranges in the file */
 586         while (rp = avl_last(&dn->dn_ranges[txgoff])) {
 587                 dnode_sync_free_range(dn, rp->fr_blkid, rp->fr_nblks, tx);
 588                 /* grab the mutex so we don't race with dnode_block_freed() */
 589                 mutex_enter(&dn->dn_mtx);
 590                 avl_remove(&dn->dn_ranges[txgoff], rp);
 591                 mutex_exit(&dn->dn_mtx);
 592                 kmem_free(rp, sizeof (free_range_t));
 593         }
 594
 595         if (dn->dn_free_txg > 0 && dn->dn_free_txg <= tx->tx_txg) {
 596                 dnode_sync_free(dn, tx);
 597                 return;
 598         }
 599
 600         if (dn->dn_next_nblkptr[txgoff]) {
 601                 /* this should only happen on a realloc */
 602                 ASSERT(dn->dn_allocated_txg == tx->tx_txg);
 603                 if (dn->dn_next_nblkptr[txgoff] > dnp->dn_nblkptr) {
 604                         /* zero the new blkptrs we are gaining */
 605                         bzero(dnp->dn_blkptr + dnp->dn_nblkptr,
 606                             sizeof (blkptr_t) *
 607                             (dn->dn_next_nblkptr[txgoff] - dnp->dn_nblkptr));
 608 #ifdef ZFS_DEBUG
 609                 } else {
 610                         int i;
 611                         ASSERT(dn->dn_next_nblkptr[txgoff] < dnp->dn_nblkptr);
 612                         /* the blkptrs we are losing better be unallocated */
 613                         for (i = dn->dn_next_nblkptr[txgoff];
 614                             i < dnp->dn_nblkptr; i++)
 615                                 ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[i]));
 616 #endif
 617                 }
 618                 mutex_enter(&dn->dn_mtx);
 619                 dnp->dn_nblkptr = dn->dn_next_nblkptr[txgoff];
 620                 dn->dn_next_nblkptr[txgoff] = 0;
 621                 mutex_exit(&dn->dn_mtx);
 622         }
 623
 624         if (dn->dn_next_nlevels[txgoff]) {
 625                 dnode_increase_indirection(dn, tx);
 626                 dn->dn_next_nlevels[txgoff] = 0;
 627         }
 628
 629         dbuf_sync_list(list, tx);
 630
 631         if (dn->dn_object != DMU_META_DNODE_OBJECT) {
 632                 ASSERT3P(list_head(list), ==, NULL);
 633                 dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
 634         }
 635
 636         /*
 637          * Although we have dropped our reference to the dnode, it
 638          * can't be evicted until its written, and we haven't yet
 639          * initiated the IO for the dnode's dbuf.
 640          */
 641 }