initial commit
[freebsd-arm:freebsd-arm.git] / 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 }