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 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  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
  37 static void
  38 dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
  39 {
  40         dmu_buf_impl_t *db;
  41         int txgoff = tx->tx_txg & TXG_MASK;
  42         int nblkptr = dn->dn_phys->dn_nblkptr;
  43         int old_toplvl = dn->dn_phys->dn_nlevels - 1;
  44         int new_level = dn->dn_next_nlevels[txgoff];
  45         int i;
  46
  47         rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
  48
  49         /* this dnode can't be paged out because it's dirty */
  50         ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
  51         ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
  52         ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);
  53
  54         db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
  55         ASSERT(db != NULL);
  56
  57         dn->dn_phys->dn_nlevels = new_level;
  58         dprintf("os=%p obj=%llu, increase to %d\n",
  59                 dn->dn_objset, dn->dn_object,
  60                 dn->dn_phys->dn_nlevels);
  61
  62         /* check for existing blkptrs in the dnode */
  63         for (i = 0; i < nblkptr; i++)
  64                 if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[i]))
  65                         break;
  66         if (i != nblkptr) {
  67                 /* transfer dnode's block pointers to new indirect block */
  68                 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
  69                 ASSERT(db->db.db_data);
  70                 ASSERT(arc_released(db->db_buf));
  71                 ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
  72                 bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,
  73                     sizeof (blkptr_t) * nblkptr);
  74                 arc_buf_freeze(db->db_buf);
  75         }
  76
  77         /* set dbuf's parent pointers to new indirect buf */
  78         for (i = 0; i < nblkptr; i++) {
  79                 dmu_buf_impl_t *child = dbuf_find(dn, old_toplvl, i);
  80
  81                 if (child == NULL)
  82                         continue;
  83                 ASSERT3P(child->db_dnode, ==, dn);
  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         objset_impl_t *os = dn->dn_objset;
 117         uint64_t bytesfreed = 0;
 118         int i;
 119
 120         dprintf("os=%p obj=%llx num=%d\n", os, dn->dn_object, num);
 121
 122         for (i = 0; i < num; i++, bp++) {
 123                 if (BP_IS_HOLE(bp))
 124                         continue;
 125
 126                 bytesfreed += bp_get_dasize(os->os_spa, bp);
 127                 ASSERT3U(bytesfreed, <=, DN_USED_BYTES(dn->dn_phys));
 128                 dsl_dataset_block_kill(os->os_dsl_dataset, bp, dn->dn_zio, tx);
 129                 bzero(bp, sizeof (blkptr_t));
 130         }
 131         dnode_diduse_space(dn, -bytesfreed);
 132 }
 133
 134 #ifdef ZFS_DEBUG
 135 static void
 136 free_verify(dmu_buf_impl_t *db, uint64_t start, uint64_t end, dmu_tx_t *tx)
 137 {
 138         int off, num;
 139         int i, err, epbs;
 140         uint64_t txg = tx->tx_txg;
 141
 142         epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
 143         off = start - (db->db_blkid * 1<<epbs);
 144         num = end - start + 1;
 145
 146         ASSERT3U(off, >=, 0);
 147         ASSERT3U(num, >=, 0);
 148         ASSERT3U(db->db_level, >, 0);
 149         ASSERT3U(db->db.db_size, ==, 1<<db->db_dnode->dn_phys->dn_indblkshift);
 150         ASSERT3U(off+num, <=, db->db.db_size >> SPA_BLKPTRSHIFT);
 151         ASSERT(db->db_blkptr != NULL);
 152
 153         for (i = off; i < off+num; i++) {
 154                 uint64_t *buf;
 155                 dmu_buf_impl_t *child;
 156                 dbuf_dirty_record_t *dr;
 157                 int j;
 158
 159                 ASSERT(db->db_level == 1);
 160
 161                 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);
 162                 err = dbuf_hold_impl(db->db_dnode, db->db_level-1,
 163                         (db->db_blkid << epbs) + i, TRUE, FTAG, &child);
 164                 rw_exit(&db->db_dnode->dn_struct_rwlock);
 165                 if (err == ENOENT)
 166                         continue;
 167                 ASSERT(err == 0);
 168                 ASSERT(child->db_level == 0);
 169                 dr = child->db_last_dirty;
 170                 while (dr && dr->dr_txg > txg)
 171                         dr = dr->dr_next;
 172                 ASSERT(dr == NULL || dr->dr_txg == txg);
 173
 174                 /* data_old better be zeroed */
 175                 if (dr) {
 176                         buf = dr->dt.dl.dr_data->b_data;
 177                         for (j = 0; j < child->db.db_size >> 3; j++) {
 178                                 if (buf[j] != 0) {
 179                                         panic("freed data not zero: "
 180                                             "child=%p i=%d off=%d num=%d\n",
 181                                             child, i, off, num);
 182                                 }
 183                         }
 184                 }
 185
 186                 /*
 187                  * db_data better be zeroed unless it's dirty in a
 188                  * future txg.
 189                  */
 190                 mutex_enter(&child->db_mtx);
 191                 buf = child->db.db_data;
 192                 if (buf != NULL && child->db_state != DB_FILL &&
 193                     child->db_last_dirty == NULL) {
 194                         for (j = 0; j < child->db.db_size >> 3; j++) {
 195                                 if (buf[j] != 0) {
 196                                         panic("freed data not zero: "
 197                                             "child=%p i=%d off=%d num=%d\n",
 198                                             child, i, off, num);
 199                                 }
 200                         }
 201                 }
 202                 mutex_exit(&child->db_mtx);
 203
 204                 dbuf_rele(child, FTAG);
 205         }
 206 }
 207 #endif
 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
 220         (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
 221         arc_release(db->db_buf, db);
 222         bp = (blkptr_t *)db->db.db_data;
 223
 224         epbs = db->db_dnode->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
 225         shift = (db->db_level - 1) * epbs;
 226         dbstart = db->db_blkid << epbs;
 227         start = blkid >> shift;
 228         if (dbstart < start) {
 229                 bp += start - dbstart;
 230                 all = FALSE;
 231         } else {
 232                 start = dbstart;
 233         }
 234         dbend = ((db->db_blkid + 1) << epbs) - 1;
 235         end = (blkid + nblks - 1) >> shift;
 236         if (dbend <= end)
 237                 end = dbend;
 238         else if (all)
 239                 all = trunc;
 240         ASSERT3U(start, <=, end);
 241
 242         if (db->db_level == 1) {
 243                 FREE_VERIFY(db, start, end, tx);
 244                 free_blocks(dn, bp, end-start+1, tx);
 245                 arc_buf_freeze(db->db_buf);
 246                 ASSERT(all || db->db_last_dirty);
 247                 return (all);
 248         }
 249
 250         for (i = start; i <= end; i++, bp++) {
 251                 if (BP_IS_HOLE(bp))
 252                         continue;
 253                 rw_enter(&dn->dn_struct_rwlock, RW_READER);
 254                 err = dbuf_hold_impl(dn, db->db_level-1, i, TRUE, FTAG, &subdb);
 255                 ASSERT3U(err, ==, 0);
 256                 rw_exit(&dn->dn_struct_rwlock);
 257
 258                 if (free_children(subdb, blkid, nblks, trunc, tx)) {
 259                         ASSERT3P(subdb->db_blkptr, ==, bp);
 260                         free_blocks(dn, bp, 1, tx);
 261                 } else {
 262                         all = FALSE;
 263                 }
 264                 dbuf_rele(subdb, FTAG);
 265         }
 266         arc_buf_freeze(db->db_buf);
 267 #ifdef ZFS_DEBUG
 268         bp -= (end-start)+1;
 269         for (i = start; i <= end; i++, bp++) {
 270                 if (i == start && blkid != 0)
 271                         continue;
 272                 else if (i == end && !trunc)
 273                         continue;
 274                 ASSERT3U(bp->blk_birth, ==, 0);
 275         }
 276 #endif
 277         ASSERT(all || db->db_last_dirty);
 278         return (all);
 279 }
 280
 281 /*
 282  * free_range: Traverse the indicated range of the provided file
 283  * and "free" all the blocks contained there.
 284  */
 285 static void
 286 dnode_sync_free_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx)
 287 {
 288         blkptr_t *bp = dn->dn_phys->dn_blkptr;
 289         dmu_buf_impl_t *db;
 290         int trunc, start, end, shift, i, err;
 291         int dnlevel = dn->dn_phys->dn_nlevels;
 292
 293         if (blkid > dn->dn_phys->dn_maxblkid)
 294                 return;
 295
 296         ASSERT(dn->dn_phys->dn_maxblkid < UINT64_MAX);
 297         trunc = blkid + nblks > dn->dn_phys->dn_maxblkid;
 298         if (trunc)
 299                 nblks = dn->dn_phys->dn_maxblkid - blkid + 1;
 300
 301         /* There are no indirect blocks in the object */
 302         if (dnlevel == 1) {
 303                 if (blkid >= dn->dn_phys->dn_nblkptr) {
 304                         /* this range was never made persistent */
 305                         return;
 306                 }
 307                 ASSERT3U(blkid + nblks, <=, dn->dn_phys->dn_nblkptr);
 308                 free_blocks(dn, bp + blkid, nblks, tx);
 309                 if (trunc) {
 310                         uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *
 311                             (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 312                         dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);
 313                         ASSERT(off < dn->dn_phys->dn_maxblkid ||
 314                             dn->dn_phys->dn_maxblkid == 0 ||
 315                             dnode_next_offset(dn, FALSE, &off,
 316                             1, 1, 0) != 0);
 317                 }
 318                 return;
 319         }
 320
 321         shift = (dnlevel - 1) * (dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT);
 322         start = blkid >> shift;
 323         ASSERT(start < dn->dn_phys->dn_nblkptr);
 324         end = (blkid + nblks - 1) >> shift;
 325         bp += start;
 326         for (i = start; i <= end; i++, bp++) {
 327                 if (BP_IS_HOLE(bp))
 328                         continue;
 329                 rw_enter(&dn->dn_struct_rwlock, RW_READER);
 330                 err = dbuf_hold_impl(dn, dnlevel-1, i, TRUE, FTAG, &db);
 331                 ASSERT3U(err, ==, 0);
 332                 rw_exit(&dn->dn_struct_rwlock);
 333
 334                 if (free_children(db, blkid, nblks, trunc, tx)) {
 335                         ASSERT3P(db->db_blkptr, ==, bp);
 336                         free_blocks(dn, bp, 1, tx);
 337                 }
 338                 dbuf_rele(db, FTAG);
 339         }
 340         if (trunc) {
 341                 uint64_t off = (dn->dn_phys->dn_maxblkid + 1) *
 342                     (dn->dn_phys->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 343                 dn->dn_phys->dn_maxblkid = (blkid ? blkid - 1 : 0);
 344                 ASSERT(off < dn->dn_phys->dn_maxblkid ||
 345                     dn->dn_phys->dn_maxblkid == 0 ||
 346                     dnode_next_offset(dn, FALSE, &off, 1, 1, 0) != 0);
 347         }
 348 }
 349
 350 /*
 351  * Try to kick all the dnodes dbufs out of the cache...
 352  */
 353 int
 354 dnode_evict_dbufs(dnode_t *dn, int try)
 355 {
 356         int progress;
 357         int pass = 0;
 358
 359         do {
 360                 dmu_buf_impl_t *db, marker;
 361                 int evicting = FALSE;
 362
 363                 progress = FALSE;
 364                 mutex_enter(&dn->dn_dbufs_mtx);
 365                 list_insert_tail(&dn->dn_dbufs, &marker);
 366                 db = list_head(&dn->dn_dbufs);
 367                 for (; db != &marker; db = list_head(&dn->dn_dbufs)) {
 368                         list_remove(&dn->dn_dbufs, db);
 369                         list_insert_tail(&dn->dn_dbufs, db);
 370
 371                         mutex_enter(&db->db_mtx);
 372                         if (db->db_state == DB_EVICTING) {
 373                                 progress = TRUE;
 374                                 evicting = TRUE;
 375                                 mutex_exit(&db->db_mtx);
 376                         } else if (refcount_is_zero(&db->db_holds)) {
 377                                 progress = TRUE;
 378                                 ASSERT(!arc_released(db->db_buf));
 379                                 dbuf_clear(db); /* exits db_mtx for us */
 380                         } else {
 381                                 mutex_exit(&db->db_mtx);
 382                         }
 383
 384                 }
 385                 list_remove(&dn->dn_dbufs, &marker);
 386                 /*
 387                  * NB: we need to drop dn_dbufs_mtx between passes so
 388                  * that any DB_EVICTING dbufs can make progress.
 389                  * Ideally, we would have some cv we could wait on, but
 390                  * since we don't, just wait a bit to give the other
 391                  * thread a chance to run.
 392                  */
 393                 mutex_exit(&dn->dn_dbufs_mtx);
 394                 if (evicting)
 395                         delay(1);
 396                 pass++;
 397                 ASSERT(pass < 100); /* sanity check */
 398         } while (progress);
 399
 400         /*
 401          * This function works fine even if it can't evict everything.
 402          * If were only asked to try to evict everything then
 403          * return an error if we can't. Otherwise panic as the caller
 404          * expects total eviction.
 405          */
 406         if (list_head(&dn->dn_dbufs) != NULL) {
 407                 if (try) {
 408                         return (1);
 409                 } else {
 410                         panic("dangling dbufs (dn=%p, dbuf=%p)\n",
 411                             dn, list_head(&dn->dn_dbufs));
 412                 }
 413         }
 414
 415         rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
 416         if (dn->dn_bonus && refcount_is_zero(&dn->dn_bonus->db_holds)) {
 417                 mutex_enter(&dn->dn_bonus->db_mtx);
 418                 dbuf_evict(dn->dn_bonus);
 419                 dn->dn_bonus = NULL;
 420         }
 421         rw_exit(&dn->dn_struct_rwlock);
 422         return (0);
 423 }
 424
 425 static void
 426 dnode_undirty_dbufs(list_t *list)
 427 {
 428         dbuf_dirty_record_t *dr;
 429
 430         while (dr = list_head(list)) {
 431                 dmu_buf_impl_t *db = dr->dr_dbuf;
 432                 uint64_t txg = dr->dr_txg;
 433
 434                 mutex_enter(&db->db_mtx);
 435                 /* XXX - use dbuf_undirty()? */
 436                 list_remove(list, dr);
 437                 ASSERT(db->db_last_dirty == dr);
 438                 db->db_last_dirty = NULL;
 439                 db->db_dirtycnt -= 1;
 440                 if (db->db_level == 0) {
 441                         ASSERT(db->db_blkid == DB_BONUS_BLKID ||
 442                             dr->dt.dl.dr_data == db->db_buf);
 443                         dbuf_unoverride(dr);
 444                         mutex_exit(&db->db_mtx);
 445                 } else {
 446                         mutex_exit(&db->db_mtx);
 447                         dnode_undirty_dbufs(&dr->dt.di.dr_children);
 448                         list_destroy(&dr->dt.di.dr_children);
 449                         mutex_destroy(&dr->dt.di.dr_mtx);
 450                 }
 451                 kmem_free(dr, sizeof (dbuf_dirty_record_t));
 452                 dbuf_rele(db, (void *)(uintptr_t)txg);
 453         }
 454 }
 455
 456 static void
 457 dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
 458 {
 459         int txgoff = tx->tx_txg & TXG_MASK;
 460
 461         ASSERT(dmu_tx_is_syncing(tx));
 462
 463         dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
 464         (void) dnode_evict_dbufs(dn, 0);
 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         /* free up all the blocks in the file. */
 483         dnode_sync_free_range(dn, 0, dn->dn_phys->dn_maxblkid+1, tx);
 484         ASSERT3U(DN_USED_BYTES(dn->dn_phys), ==, 0);
 485
 486         /* ASSERT(blkptrs are zero); */
 487         ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
 488         ASSERT(dn->dn_type != DMU_OT_NONE);
 489
 490         ASSERT(dn->dn_free_txg > 0);
 491         if (dn->dn_allocated_txg != dn->dn_free_txg)
 492                 dbuf_will_dirty(dn->dn_dbuf, tx);
 493         bzero(dn->dn_phys, sizeof (dnode_phys_t));
 494
 495         mutex_enter(&dn->dn_mtx);
 496         dn->dn_type = DMU_OT_NONE;
 497         dn->dn_maxblkid = 0;
 498         dn->dn_allocated_txg = 0;
 499         mutex_exit(&dn->dn_mtx);
 500
 501         ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
 502
 503         dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
 504         /*
 505          * Now that we've released our hold, the dnode may
 506          * be evicted, so we musn't access it.
 507          */
 508 }
 509
 510 /*
 511  * Write out the dnode's dirty buffers.
 512  *
 513  * NOTE: The dnode is kept in memory by being dirty.  Once the
 514  * dirty bit is cleared, it may be evicted.  Beware of this!
 515  */
 516 void
 517 dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 518 {
 519         free_range_t *rp;
 520         dnode_phys_t *dnp = dn->dn_phys;
 521         int txgoff = tx->tx_txg & TXG_MASK;
 522         list_t *list = &dn->dn_dirty_records[txgoff];
 523
 524         ASSERT(dmu_tx_is_syncing(tx));
 525         ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg);
 526         DNODE_VERIFY(dn);
 527
 528         ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf));
 529
 530         mutex_enter(&dn->dn_mtx);
 531         if (dn->dn_allocated_txg == tx->tx_txg) {
 532                 /* The dnode is newly allocated or reallocated */
 533                 if (dnp->dn_type == DMU_OT_NONE) {
 534                         /* this is a first alloc, not a realloc */
 535                         /* XXX shouldn't the phys already be zeroed? */
 536                         bzero(dnp, DNODE_CORE_SIZE);
 537                         dnp->dn_nlevels = 1;
 538                 }
 539
 540                 if (dn->dn_nblkptr > dnp->dn_nblkptr) {
 541                         /* zero the new blkptrs we are gaining */
 542                         bzero(dnp->dn_blkptr + dnp->dn_nblkptr,
 543                             sizeof (blkptr_t) *
 544                             (dn->dn_nblkptr - dnp->dn_nblkptr));
 545                 }
 546                 dnp->dn_type = dn->dn_type;
 547                 dnp->dn_bonustype = dn->dn_bonustype;
 548                 dnp->dn_bonuslen = dn->dn_bonuslen;
 549                 dnp->dn_nblkptr = dn->dn_nblkptr;
 550         }
 551
 552         ASSERT(dnp->dn_nlevels > 1 ||
 553             BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
 554             BP_GET_LSIZE(&dnp->dn_blkptr[0]) ==
 555             dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
 556
 557         if (dn->dn_next_blksz[txgoff]) {
 558                 ASSERT(P2PHASE(dn->dn_next_blksz[txgoff],
 559                     SPA_MINBLOCKSIZE) == 0);
 560                 ASSERT(BP_IS_HOLE(&dnp->dn_blkptr[0]) ||
 561                     list_head(list) != NULL ||
 562                     dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT ==
 563                     dnp->dn_datablkszsec);
 564                 dnp->dn_datablkszsec =
 565                     dn->dn_next_blksz[txgoff] >> SPA_MINBLOCKSHIFT;
 566                 dn->dn_next_blksz[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         if (dn->dn_free_txg == 0 || dn->dn_free_txg > tx->tx_txg) {
 587                 for (rp = avl_last(&dn->dn_ranges[txgoff]); rp != NULL;
 588                     rp = AVL_PREV(&dn->dn_ranges[txgoff], rp))
 589                         dnode_sync_free_range(dn,
 590                             rp->fr_blkid, rp->fr_nblks, tx);
 591         }
 592         mutex_enter(&dn->dn_mtx);
 593         for (rp = avl_first(&dn->dn_ranges[txgoff]); rp; ) {
 594                 free_range_t *last = rp;
 595                 rp = AVL_NEXT(&dn->dn_ranges[txgoff], rp);
 596                 avl_remove(&dn->dn_ranges[txgoff], last);
 597                 kmem_free(last, sizeof (free_range_t));
 598         }
 599         mutex_exit(&dn->dn_mtx);
 600
 601         if (dn->dn_free_txg > 0 && dn->dn_free_txg <= tx->tx_txg) {
 602                 dnode_sync_free(dn, tx);
 603                 return;
 604         }
 605
 606         if (dn->dn_next_nlevels[txgoff]) {
 607                 dnode_increase_indirection(dn, tx);
 608                 dn->dn_next_nlevels[txgoff] = 0;
 609         }
 610
 611         dbuf_sync_list(list, tx);
 612
 613         if (dn->dn_object != DMU_META_DNODE_OBJECT) {
 614                 ASSERT3P(list_head(list), ==, NULL);
 615                 dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
 616         }
 617
 618         /*
 619          * Although we have dropped our reference to the dnode, it
 620          * can't be evicted until its written, and we haven't yet
 621          * initiated the IO for the dnode's dbuf.
 622          */
 623 }