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 2010 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #include <sys/zfs_context.h>
27 #include <sys/dmu.h>
28 #include <sys/dmu_impl.h>
29 #include <sys/dbuf.h>
30 #include <sys/dmu_objset.h>
31 #include <sys/dsl_dataset.h>
32 #include <sys/dsl_dir.h>
33 #include <sys/dmu_tx.h>
34 #include <sys/spa.h>
35 #include <sys/zio.h>
36 #include <sys/dmu_zfetch.h>
37
38 static void dbuf_destroy(dmu_buf_impl_t *db);
39 static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
40 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
41
42 /*
43 * Global data structures and functions for the dbuf cache.
44 */
45 static kmem_cache_t *dbuf_cache;
46
47 /* ARGSUSED */
48 static int
dbuf_cons(void * vdb,void * unused,int kmflag)49 dbuf_cons(void *vdb, void *unused, int kmflag)
50 {
51 dmu_buf_impl_t *db = unused;
52 bzero(db, sizeof (dmu_buf_impl_t));
53
54 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
55 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
56 refcount_create(&db->db_holds);
57 return (0);
58 }
59
60 /* ARGSUSED */
61 static void
dbuf_dest(void * vdb,void * unused)62 dbuf_dest(void *vdb, void *unused)
63 {
64 dmu_buf_impl_t *db = unused;
65 mutex_destroy(&db->db_mtx);
66 cv_destroy(&db->db_changed);
67 refcount_destroy(&db->db_holds);
68 }
69
70 /*
71 * dbuf hash table routines
72 */
73 static dbuf_hash_table_t dbuf_hash_table;
74
75 static uint64_t dbuf_hash_count;
76
77 static uint64_t
dbuf_hash(void * os,uint64_t obj,uint8_t lvl,uint64_t blkid)78 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
79 {
80 uintptr_t osv = (uintptr_t)os;
81 uint64_t crc = -1ULL;
82
83 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
84 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
85 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
86 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
87 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
88 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
89 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
90
91 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
92
93 return (crc);
94 }
95
96 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
97
98 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
99 ((dbuf)->db.db_object == (obj) && \
100 (dbuf)->db_objset == (os) && \
101 (dbuf)->db_level == (level) && \
102 (dbuf)->db_blkid == (blkid))
103
104 dmu_buf_impl_t *
dbuf_find(dnode_t * dn,uint8_t level,uint64_t blkid)105 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
106 {
107 dbuf_hash_table_t *h = &dbuf_hash_table;
108 objset_t *os = dn->dn_objset;
109 uint64_t obj = dn->dn_object;
110 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
111 uint64_t idx = hv & h->hash_table_mask;
112 dmu_buf_impl_t *db;
113
114 mutex_enter(DBUF_HASH_MUTEX(h, idx));
115 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
116 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
117 mutex_enter(&db->db_mtx);
118 if (db->db_state != DB_EVICTING) {
119 mutex_exit(DBUF_HASH_MUTEX(h, idx));
120 return (db);
121 }
122 mutex_exit(&db->db_mtx);
123 }
124 }
125 mutex_exit(DBUF_HASH_MUTEX(h, idx));
126 return (NULL);
127 }
128
129 /*
130 * Insert an entry into the hash table. If there is already an element
131 * equal to elem in the hash table, then the already existing element
132 * will be returned and the new element will not be inserted.
133 * Otherwise returns NULL.
134 */
135 static dmu_buf_impl_t *
dbuf_hash_insert(dmu_buf_impl_t * db)136 dbuf_hash_insert(dmu_buf_impl_t *db)
137 {
138 dbuf_hash_table_t *h = &dbuf_hash_table;
139 objset_t *os = db->db_objset;
140 uint64_t obj = db->db.db_object;
141 int level = db->db_level;
142 uint64_t blkid = db->db_blkid;
143 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
144 uint64_t idx = hv & h->hash_table_mask;
145 dmu_buf_impl_t *dbf;
146
147 mutex_enter(DBUF_HASH_MUTEX(h, idx));
148 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
149 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
150 mutex_enter(&dbf->db_mtx);
151 if (dbf->db_state != DB_EVICTING) {
152 mutex_exit(DBUF_HASH_MUTEX(h, idx));
153 return (dbf);
154 }
155 mutex_exit(&dbf->db_mtx);
156 }
157 }
158
159 mutex_enter(&db->db_mtx);
160 db->db_hash_next = h->hash_table[idx];
161 h->hash_table[idx] = db;
162 mutex_exit(DBUF_HASH_MUTEX(h, idx));
163 atomic_add_64(&dbuf_hash_count, 1);
164
165 return (NULL);
166 }
167
168 /*
169 * Remove an entry from the hash table. This operation will
170 * fail if there are any existing holds on the db.
171 */
172 static void
dbuf_hash_remove(dmu_buf_impl_t * db)173 dbuf_hash_remove(dmu_buf_impl_t *db)
174 {
175 dbuf_hash_table_t *h = &dbuf_hash_table;
176 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
177 db->db_level, db->db_blkid);
178 uint64_t idx = hv & h->hash_table_mask;
179 dmu_buf_impl_t *dbf, **dbp;
180
181 /*
182 * We musn't hold db_mtx to maintin lock ordering:
183 * DBUF_HASH_MUTEX > db_mtx.
184 */
185 ASSERT(refcount_is_zero(&db->db_holds));
186 ASSERT(db->db_state == DB_EVICTING);
187 ASSERT(!MUTEX_HELD(&db->db_mtx));
188
189 mutex_enter(DBUF_HASH_MUTEX(h, idx));
190 dbp = &h->hash_table[idx];
191 while ((dbf = *dbp) != db) {
192 dbp = &dbf->db_hash_next;
193 ASSERT(dbf != NULL);
194 }
195 *dbp = db->db_hash_next;
196 db->db_hash_next = NULL;
197 mutex_exit(DBUF_HASH_MUTEX(h, idx));
198 atomic_add_64(&dbuf_hash_count, -1);
199 }
200
201 static arc_evict_func_t dbuf_do_evict;
202
203 static void
dbuf_evict_user(dmu_buf_impl_t * db)204 dbuf_evict_user(dmu_buf_impl_t *db)
205 {
206 ASSERT(MUTEX_HELD(&db->db_mtx));
207
208 if (db->db_level != 0 || db->db_evict_func == NULL)
209 return;
210
211 if (db->db_user_data_ptr_ptr)
212 *db->db_user_data_ptr_ptr = db->db.db_data;
213 db->db_evict_func(&db->db, db->db_user_ptr);
214 db->db_user_ptr = NULL;
215 db->db_user_data_ptr_ptr = NULL;
216 db->db_evict_func = NULL;
217 }
218
219 void
dbuf_evict(dmu_buf_impl_t * db)220 dbuf_evict(dmu_buf_impl_t *db)
221 {
222 ASSERT(MUTEX_HELD(&db->db_mtx));
223 ASSERT(db->db_buf == NULL);
224 ASSERT(db->db_data_pending == NULL);
225
226 dbuf_clear(db);
227 dbuf_destroy(db);
228 }
229
230 void
dbuf_init(void)231 dbuf_init(void)
232 {
233 uint64_t hsize = 1ULL << 16;
234 dbuf_hash_table_t *h = &dbuf_hash_table;
235 int i;
236
237 /*
238 * The hash table is big enough to fill all of physical memory
239 * with an average 4K block size. The table will take up
240 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
241 */
242 while (hsize * 4096 < (uint64_t)physmem * PAGESIZE)
243 hsize <<= 1;
244
245 retry:
246 h->hash_table_mask = hsize - 1;
247 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
248 if (h->hash_table == NULL) {
249 /* XXX - we should really return an error instead of assert */
250 ASSERT(hsize > (1ULL << 10));
251 hsize >>= 1;
252 goto retry;
253 }
254
255 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
256 sizeof (dmu_buf_impl_t),
257 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
258
259 for (i = 0; i < DBUF_MUTEXES; i++)
260 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
261 }
262
263 void
dbuf_fini(void)264 dbuf_fini(void)
265 {
266 dbuf_hash_table_t *h = &dbuf_hash_table;
267 int i;
268
269 for (i = 0; i < DBUF_MUTEXES; i++)
270 mutex_destroy(&h->hash_mutexes[i]);
271 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
272 kmem_cache_destroy(dbuf_cache);
273 }
274
275 /*
276 * Other stuff.
277 */
278
279 #ifdef ZFS_DEBUG
280 static void
dbuf_verify(dmu_buf_impl_t * db)281 dbuf_verify(dmu_buf_impl_t *db)
282 {
283 dnode_t *dn = db->db_dnode;
284 dbuf_dirty_record_t *dr;
285
286 ASSERT(MUTEX_HELD(&db->db_mtx));
287
288 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
289 return;
290
291 ASSERT(db->db_objset != NULL);
292 if (dn == NULL) {
293 ASSERT(db->db_parent == NULL);
294 ASSERT(db->db_blkptr == NULL);
295 } else {
296 ASSERT3U(db->db.db_object, ==, dn->dn_object);
297 ASSERT3P(db->db_objset, ==, dn->dn_objset);
298 ASSERT3U(db->db_level, <, dn->dn_nlevels);
299 ASSERT(db->db_blkid == DB_BONUS_BLKID ||
300 list_head(&dn->dn_dbufs));
301 }
302 if (db->db_blkid == DB_BONUS_BLKID) {
303 ASSERT(dn != NULL);
304 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
305 ASSERT3U(db->db.db_offset, ==, DB_BONUS_BLKID);
306 } else {
307 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
308 }
309
310 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
311 ASSERT(dr->dr_dbuf == db);
312
313 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
314 ASSERT(dr->dr_dbuf == db);
315
316 /*
317 * We can't assert that db_size matches dn_datablksz because it
318 * can be momentarily different when another thread is doing
319 * dnode_set_blksz().
320 */
321 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
322 dr = db->db_data_pending;
323 /*
324 * It should only be modified in syncing context, so
325 * make sure we only have one copy of the data.
326 */
327 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
328 }
329
330 /* verify db->db_blkptr */
331 if (db->db_blkptr) {
332 if (db->db_parent == dn->dn_dbuf) {
333 /* db is pointed to by the dnode */
334 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
335 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
336 ASSERT(db->db_parent == NULL);
337 else
338 ASSERT(db->db_parent != NULL);
339 ASSERT3P(db->db_blkptr, ==,
340 &dn->dn_phys->dn_blkptr[db->db_blkid]);
341 } else {
342 /* db is pointed to by an indirect block */
343 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
344 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
345 ASSERT3U(db->db_parent->db.db_object, ==,
346 db->db.db_object);
347 /*
348 * dnode_grow_indblksz() can make this fail if we don't
349 * have the struct_rwlock. XXX indblksz no longer
350 * grows. safe to do this now?
351 */
352 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock)) {
353 ASSERT3P(db->db_blkptr, ==,
354 ((blkptr_t *)db->db_parent->db.db_data +
355 db->db_blkid % epb));
356 }
357 }
358 }
359 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
360 db->db.db_data && db->db_blkid != DB_BONUS_BLKID &&
361 db->db_state != DB_FILL && !dn->dn_free_txg) {
362 /*
363 * If the blkptr isn't set but they have nonzero data,
364 * it had better be dirty, otherwise we'll lose that
365 * data when we evict this buffer.
366 */
367 if (db->db_dirtycnt == 0) {
368 uint64_t *buf = db->db.db_data;
369 int i;
370
371 for (i = 0; i < db->db.db_size >> 3; i++) {
372 ASSERT(buf[i] == 0);
373 }
374 }
375 }
376 }
377 #endif
378
379 static void
dbuf_update_data(dmu_buf_impl_t * db)380 dbuf_update_data(dmu_buf_impl_t *db)
381 {
382 ASSERT(MUTEX_HELD(&db->db_mtx));
383 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
384 ASSERT(!refcount_is_zero(&db->db_holds));
385 *db->db_user_data_ptr_ptr = db->db.db_data;
386 }
387 }
388
389 static void
dbuf_set_data(dmu_buf_impl_t * db,arc_buf_t * buf)390 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
391 {
392 ASSERT(MUTEX_HELD(&db->db_mtx));
393 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
394 db->db_buf = buf;
395 if (buf != NULL) {
396 ASSERT(buf->b_data != NULL);
397 db->db.db_data = buf->b_data;
398 if (!arc_released(buf))
399 arc_set_callback(buf, dbuf_do_evict, db);
400 dbuf_update_data(db);
401 } else {
402 dbuf_evict_user(db);
403 db->db.db_data = NULL;
404 if (db->db_state != DB_NOFILL)
405 db->db_state = DB_UNCACHED;
406 }
407 }
408
409 /*
410 * Loan out an arc_buf for read. Return the loaned arc_buf.
411 */
412 arc_buf_t *
dbuf_loan_arcbuf(dmu_buf_impl_t * db)413 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
414 {
415 arc_buf_t *abuf;
416
417 mutex_enter(&db->db_mtx);
418 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
419 int blksz = db->db.db_size;
420 mutex_exit(&db->db_mtx);
421 abuf = arc_loan_buf(db->db_dnode->dn_objset->os_spa, blksz);
422 bcopy(db->db.db_data, abuf->b_data, blksz);
423 } else {
424 abuf = db->db_buf;
425 arc_loan_inuse_buf(abuf, db);
426 dbuf_set_data(db, NULL);
427 mutex_exit(&db->db_mtx);
428 }
429 return (abuf);
430 }
431
432 uint64_t
dbuf_whichblock(dnode_t * dn,uint64_t offset)433 dbuf_whichblock(dnode_t *dn, uint64_t offset)
434 {
435 if (dn->dn_datablkshift) {
436 return (offset >> dn->dn_datablkshift);
437 } else {
438 ASSERT3U(offset, <, dn->dn_datablksz);
439 return (0);
440 }
441 }
442
443 static void
dbuf_read_done(zio_t * zio,arc_buf_t * buf,void * vdb)444 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
445 {
446 dmu_buf_impl_t *db = vdb;
447
448 mutex_enter(&db->db_mtx);
449 ASSERT3U(db->db_state, ==, DB_READ);
450 /*
451 * All reads are synchronous, so we must have a hold on the dbuf
452 */
453 ASSERT(refcount_count(&db->db_holds) > 0);
454 ASSERT(db->db_buf == NULL);
455 ASSERT(db->db.db_data == NULL);
456 if (db->db_level == 0 && db->db_freed_in_flight) {
457 /* we were freed in flight; disregard any error */
458 arc_release(buf, db);
459 bzero(buf->b_data, db->db.db_size);
460 arc_buf_freeze(buf);
461 db->db_freed_in_flight = FALSE;
462 dbuf_set_data(db, buf);
463 db->db_state = DB_CACHED;
464 } else if (zio == NULL || zio->io_error == 0) {
465 dbuf_set_data(db, buf);
466 db->db_state = DB_CACHED;
467 } else {
468 ASSERT(db->db_blkid != DB_BONUS_BLKID);
469 ASSERT3P(db->db_buf, ==, NULL);
470 VERIFY(arc_buf_remove_ref(buf, db) == 1);
471 db->db_state = DB_UNCACHED;
472 }
473 cv_broadcast(&db->db_changed);
474 mutex_exit(&db->db_mtx);
475 dbuf_rele(db, NULL);
476 }
477
478 static void
dbuf_read_impl(dmu_buf_impl_t * db,zio_t * zio,uint32_t * flags)479 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
480 {
481 dnode_t *dn = db->db_dnode;
482 zbookmark_t zb;
483 uint32_t aflags = ARC_NOWAIT;
484 arc_buf_t *pbuf;
485
486 ASSERT(!refcount_is_zero(&db->db_holds));
487 /* We need the struct_rwlock to prevent db_blkptr from changing. */
488 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
489 ASSERT(MUTEX_HELD(&db->db_mtx));
490 ASSERT(db->db_state == DB_UNCACHED);
491 ASSERT(db->db_buf == NULL);
492
493 if (db->db_blkid == DB_BONUS_BLKID) {
494 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
495
496 ASSERT3U(bonuslen, <=, db->db.db_size);
497 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
498 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
499 if (bonuslen < DN_MAX_BONUSLEN)
500 bzero(db->db.db_data, DN_MAX_BONUSLEN);
501 if (bonuslen)
502 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
503 dbuf_update_data(db);
504 db->db_state = DB_CACHED;
505 mutex_exit(&db->db_mtx);
506 return;
507 }
508
509 /*
510 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
511 * processes the delete record and clears the bp while we are waiting
512 * for the dn_mtx (resulting in a "no" from block_freed).
513 */
514 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
515 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
516 BP_IS_HOLE(db->db_blkptr)))) {
517 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
518
519 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
520 db->db.db_size, db, type));
521 bzero(db->db.db_data, db->db.db_size);
522 db->db_state = DB_CACHED;
523 *flags |= DB_RF_CACHED;
524 mutex_exit(&db->db_mtx);
525 return;
526 }
527
528 db->db_state = DB_READ;
529 mutex_exit(&db->db_mtx);
530
531 if (DBUF_IS_L2CACHEABLE(db))
532 aflags |= ARC_L2CACHE;
533
534 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
535 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
536 db->db.db_object, db->db_level, db->db_blkid);
537
538 dbuf_add_ref(db, NULL);
539 /* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */
540
541 if (db->db_parent)
542 pbuf = db->db_parent->db_buf;
543 else
544 pbuf = db->db_objset->os_phys_buf;
545
546 (void) arc_read(zio, dn->dn_objset->os_spa, db->db_blkptr, pbuf,
547 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
548 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
549 &aflags, &zb);
550 if (aflags & ARC_CACHED)
551 *flags |= DB_RF_CACHED;
552 }
553
554 int
dbuf_read(dmu_buf_impl_t * db,zio_t * zio,uint32_t flags)555 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
556 {
557 int err = 0;
558 int havepzio = (zio != NULL);
559 int prefetch;
560
561 /*
562 * We don't have to hold the mutex to check db_state because it
563 * can't be freed while we have a hold on the buffer.
564 */
565 ASSERT(!refcount_is_zero(&db->db_holds));
566
567 if (db->db_state == DB_NOFILL)
568 return (EIO);
569
570 if ((flags & DB_RF_HAVESTRUCT) == 0)
571 rw_enter(&db->db_dnode->dn_struct_rwlock, RW_READER);
572
573 prefetch = db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID &&
574 (flags & DB_RF_NOPREFETCH) == 0 && db->db_dnode != NULL &&
575 DBUF_IS_CACHEABLE(db);
576
577 mutex_enter(&db->db_mtx);
578 if (db->db_state == DB_CACHED) {
579 mutex_exit(&db->db_mtx);
580 if (prefetch)
581 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset,
582 db->db.db_size, TRUE);
583 if ((flags & DB_RF_HAVESTRUCT) == 0)
584 rw_exit(&db->db_dnode->dn_struct_rwlock);
585 } else if (db->db_state == DB_UNCACHED) {
586 if (zio == NULL) {
587 zio = zio_root(db->db_dnode->dn_objset->os_spa,
588 NULL, NULL, ZIO_FLAG_CANFAIL);
589 }
590 dbuf_read_impl(db, zio, &flags);
591
592 /* dbuf_read_impl has dropped db_mtx for us */
593
594 if (prefetch)
595 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset,
596 db->db.db_size, flags & DB_RF_CACHED);
597
598 if ((flags & DB_RF_HAVESTRUCT) == 0)
599 rw_exit(&db->db_dnode->dn_struct_rwlock);
600
601 if (!havepzio)
602 err = zio_wait(zio);
603 } else {
604 mutex_exit(&db->db_mtx);
605 if (prefetch)
606 dmu_zfetch(&db->db_dnode->dn_zfetch, db->db.db_offset,
607 db->db.db_size, TRUE);
608 if ((flags & DB_RF_HAVESTRUCT) == 0)
609 rw_exit(&db->db_dnode->dn_struct_rwlock);
610
611 mutex_enter(&db->db_mtx);
612 if ((flags & DB_RF_NEVERWAIT) == 0) {
613 while (db->db_state == DB_READ ||
614 db->db_state == DB_FILL) {
615 ASSERT(db->db_state == DB_READ ||
616 (flags & DB_RF_HAVESTRUCT) == 0);
617 cv_wait(&db->db_changed, &db->db_mtx);
618 }
619 if (db->db_state == DB_UNCACHED)
620 err = EIO;
621 }
622 mutex_exit(&db->db_mtx);
623 }
624
625 ASSERT(err || havepzio || db->db_state == DB_CACHED);
626 return (err);
627 }
628
629 static void
dbuf_noread(dmu_buf_impl_t * db)630 dbuf_noread(dmu_buf_impl_t *db)
631 {
632 ASSERT(!refcount_is_zero(&db->db_holds));
633 ASSERT(db->db_blkid != DB_BONUS_BLKID);
634 mutex_enter(&db->db_mtx);
635 while (db->db_state == DB_READ || db->db_state == DB_FILL)
636 cv_wait(&db->db_changed, &db->db_mtx);
637 if (db->db_state == DB_UNCACHED) {
638 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
639
640 ASSERT(db->db_buf == NULL);
641 ASSERT(db->db.db_data == NULL);
642 dbuf_set_data(db, arc_buf_alloc(db->db_dnode->dn_objset->os_spa,
643 db->db.db_size, db, type));
644 db->db_state = DB_FILL;
645 } else if (db->db_state == DB_NOFILL) {
646 dbuf_set_data(db, NULL);
647 } else {
648 ASSERT3U(db->db_state, ==, DB_CACHED);
649 }
650 mutex_exit(&db->db_mtx);
651 }
652
653 /*
654 * This is our just-in-time copy function. It makes a copy of
655 * buffers, that have been modified in a previous transaction
656 * group, before we modify them in the current active group.
657 *
658 * This function is used in two places: when we are dirtying a
659 * buffer for the first time in a txg, and when we are freeing
660 * a range in a dnode that includes this buffer.
661 *
662 * Note that when we are called from dbuf_free_range() we do
663 * not put a hold on the buffer, we just traverse the active
664 * dbuf list for the dnode.
665 */
666 static void
dbuf_fix_old_data(dmu_buf_impl_t * db,uint64_t txg)667 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
668 {
669 dbuf_dirty_record_t *dr = db->db_last_dirty;
670
671 ASSERT(MUTEX_HELD(&db->db_mtx));
672 ASSERT(db->db.db_data != NULL);
673 ASSERT(db->db_level == 0);
674 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
675
676 if (dr == NULL ||
677 (dr->dt.dl.dr_data !=
678 ((db->db_blkid == DB_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
679 return;
680
681 /*
682 * If the last dirty record for this dbuf has not yet synced
683 * and its referencing the dbuf data, either:
684 * reset the reference to point to a new copy,
685 * or (if there a no active holders)
686 * just null out the current db_data pointer.
687 */
688 ASSERT(dr->dr_txg >= txg - 2);
689 if (db->db_blkid == DB_BONUS_BLKID) {
690 /* Note that the data bufs here are zio_bufs */
691 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
692 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
693 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
694 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
695 int size = db->db.db_size;
696 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
697 dr->dt.dl.dr_data = arc_buf_alloc(
698 db->db_dnode->dn_objset->os_spa, size, db, type);
699 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
700 } else {
701 dbuf_set_data(db, NULL);
702 }
703 }
704
705 void
dbuf_unoverride(dbuf_dirty_record_t * dr)706 dbuf_unoverride(dbuf_dirty_record_t *dr)
707 {
708 dmu_buf_impl_t *db = dr->dr_dbuf;
709 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
710 uint64_t txg = dr->dr_txg;
711
712 ASSERT(MUTEX_HELD(&db->db_mtx));
713 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
714 ASSERT(db->db_level == 0);
715
716 if (db->db_blkid == DB_BONUS_BLKID ||
717 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
718 return;
719
720 ASSERT(db->db_data_pending != dr);
721
722 /* free this block */
723 if (!BP_IS_HOLE(bp))
724 dsl_free(spa_get_dsl(db->db_dnode->dn_objset->os_spa), txg, bp);
725
726 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
727 /*
728 * Release the already-written buffer, so we leave it in
729 * a consistent dirty state. Note that all callers are
730 * modifying the buffer, so they will immediately do
731 * another (redundant) arc_release(). Therefore, leave
732 * the buf thawed to save the effort of freezing &
733 * immediately re-thawing it.
734 */
735 arc_release(dr->dt.dl.dr_data, db);
736 }
737
738 /*
739 * Evict (if its unreferenced) or clear (if its referenced) any level-0
740 * data blocks in the free range, so that any future readers will find
741 * empty blocks. Also, if we happen accross any level-1 dbufs in the
742 * range that have not already been marked dirty, mark them dirty so
743 * they stay in memory.
744 */
745 void
dbuf_free_range(dnode_t * dn,uint64_t start,uint64_t end,dmu_tx_t * tx)746 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
747 {
748 dmu_buf_impl_t *db, *db_next;
749 uint64_t txg = tx->tx_txg;
750 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
751 uint64_t first_l1 = start >> epbs;
752 uint64_t last_l1 = end >> epbs;
753
754 if (end > dn->dn_maxblkid) {
755 end = dn->dn_maxblkid;
756 last_l1 = end >> epbs;
757 }
758 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
759 mutex_enter(&dn->dn_dbufs_mtx);
760 for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
761 db_next = list_next(&dn->dn_dbufs, db);
762 ASSERT(db->db_blkid != DB_BONUS_BLKID);
763
764 if (db->db_level == 1 &&
765 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
766 mutex_enter(&db->db_mtx);
767 if (db->db_last_dirty &&
768 db->db_last_dirty->dr_txg < txg) {
769 dbuf_add_ref(db, FTAG);
770 mutex_exit(&db->db_mtx);
771 dbuf_will_dirty(db, tx);
772 dbuf_rele(db, FTAG);
773 } else {
774 mutex_exit(&db->db_mtx);
775 }
776 }
777
778 if (db->db_level != 0)
779 continue;
780 dprintf_dbuf(db, "found buf %s\n", "");
781 if (db->db_blkid < start || db->db_blkid > end)
782 continue;
783
784 /* found a level 0 buffer in the range */
785 if (dbuf_undirty(db, tx))
786 continue;
787
788 mutex_enter(&db->db_mtx);
789 if (db->db_state == DB_UNCACHED ||
790 db->db_state == DB_NOFILL ||
791 db->db_state == DB_EVICTING) {
792 ASSERT(db->db.db_data == NULL);
793 mutex_exit(&db->db_mtx);
794 continue;
795 }
796 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
797 /* will be handled in dbuf_read_done or dbuf_rele */
798 db->db_freed_in_flight = TRUE;
799 mutex_exit(&db->db_mtx);
800 continue;
801 }
802 if (refcount_count(&db->db_holds) == 0) {
803 ASSERT(db->db_buf);
804 dbuf_clear(db);
805 continue;
806 }
807 /* The dbuf is referenced */
808
809 if (db->db_last_dirty != NULL) {
810 dbuf_dirty_record_t *dr = db->db_last_dirty;
811
812 if (dr->dr_txg == txg) {
813 /*
814 * This buffer is "in-use", re-adjust the file
815 * size to reflect that this buffer may
816 * contain new data when we sync.
817 */
818 if (db->db_blkid > dn->dn_maxblkid)
819 dn->dn_maxblkid = db->db_blkid;
820 dbuf_unoverride(dr);
821 } else {
822 /*
823 * This dbuf is not dirty in the open context.
824 * Either uncache it (if its not referenced in
825 * the open context) or reset its contents to
826 * empty.
827 */
828 dbuf_fix_old_data(db, txg);
829 }
830 }
831 /* clear the contents if its cached */
832 if (db->db_state == DB_CACHED) {
833 ASSERT(db->db.db_data != NULL);
834 arc_release(db->db_buf, db);
835 bzero(db->db.db_data, db->db.db_size);
836 arc_buf_freeze(db->db_buf);
837 }
838
839 mutex_exit(&db->db_mtx);
840 }
841 mutex_exit(&dn->dn_dbufs_mtx);
842 }
843
844 static int
dbuf_block_freeable(dmu_buf_impl_t * db)845 dbuf_block_freeable(dmu_buf_impl_t *db)
846 {
847 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
848 uint64_t birth_txg = 0;
849
850 /*
851 * We don't need any locking to protect db_blkptr:
852 * If it's syncing, then db_last_dirty will be set
853 * so we'll ignore db_blkptr.
854 */
855 ASSERT(MUTEX_HELD(&db->db_mtx));
856 if (db->db_last_dirty)
857 birth_txg = db->db_last_dirty->dr_txg;
858 else if (db->db_blkptr)
859 birth_txg = db->db_blkptr->blk_birth;
860
861 /* If we don't exist or are in a snapshot, we can't be freed */
862 if (birth_txg)
863 return (ds == NULL ||
864 dsl_dataset_block_freeable(ds, birth_txg));
865 else
866 return (FALSE);
867 }
868
869 void
dbuf_new_size(dmu_buf_impl_t * db,int size,dmu_tx_t * tx)870 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
871 {
872 arc_buf_t *buf, *obuf;
873 int osize = db->db.db_size;
874 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
875
876 ASSERT(db->db_blkid != DB_BONUS_BLKID);
877
878 /* XXX does *this* func really need the lock? */
879 ASSERT(RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock));
880
881 /*
882 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
883 * is OK, because there can be no other references to the db
884 * when we are changing its size, so no concurrent DB_FILL can
885 * be happening.
886 */
887 /*
888 * XXX we should be doing a dbuf_read, checking the return
889 * value and returning that up to our callers
890 */
891 dbuf_will_dirty(db, tx);
892
893 /* create the data buffer for the new block */
894 buf = arc_buf_alloc(db->db_dnode->dn_objset->os_spa, size, db, type);
895
896 /* copy old block data to the new block */
897 obuf = db->db_buf;
898 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
899 /* zero the remainder */
900 if (size > osize)
901 bzero((uint8_t *)buf->b_data + osize, size - osize);
902
903 mutex_enter(&db->db_mtx);
904 dbuf_set_data(db, buf);
905 VERIFY(arc_buf_remove_ref(obuf, db) == 1);
906 db->db.db_size = size;
907
908 if (db->db_level == 0) {
909 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
910 db->db_last_dirty->dt.dl.dr_data = buf;
911 }
912 mutex_exit(&db->db_mtx);
913
914 dnode_willuse_space(db->db_dnode, size-osize, tx);
915 }
916
917 dbuf_dirty_record_t *
dbuf_dirty(dmu_buf_impl_t * db,dmu_tx_t * tx)918 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
919 {
920 dnode_t *dn = db->db_dnode;
921 objset_t *os = dn->dn_objset;
922 dbuf_dirty_record_t **drp, *dr;
923 int drop_struct_lock = FALSE;
924 boolean_t do_free_accounting = B_FALSE;
925 int txgoff = tx->tx_txg & TXG_MASK;
926
927 ASSERT(tx->tx_txg != 0);
928 ASSERT(!refcount_is_zero(&db->db_holds));
929 DMU_TX_DIRTY_BUF(tx, db);
930
931 /*
932 * Shouldn't dirty a regular buffer in syncing context. Private
933 * objects may be dirtied in syncing context, but only if they
934 * were already pre-dirtied in open context.
935 */
936 ASSERT(!dmu_tx_is_syncing(tx) ||
937 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
938 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
939 dn->dn_objset->os_dsl_dataset == NULL);
940 /*
941 * We make this assert for private objects as well, but after we
942 * check if we're already dirty. They are allowed to re-dirty
943 * in syncing context.
944 */
945 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
946 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
947 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
948
949 mutex_enter(&db->db_mtx);
950 /*
951 * XXX make this true for indirects too? The problem is that
952 * transactions created with dmu_tx_create_assigned() from
953 * syncing context don't bother holding ahead.
954 */
955 ASSERT(db->db_level != 0 ||
956 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
957 db->db_state == DB_NOFILL);
958
959 mutex_enter(&dn->dn_mtx);
960 /*
961 * Don't set dirtyctx to SYNC if we're just modifying this as we
962 * initialize the objset.
963 */
964 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
965 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
966 dn->dn_dirtyctx =
967 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
968 ASSERT(dn->dn_dirtyctx_firstset == NULL);
969 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
970 }
971 mutex_exit(&dn->dn_mtx);
972
973 /*
974 * If this buffer is already dirty, we're done.
975 */
976 drp = &db->db_last_dirty;
977 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
978 db->db.db_object == DMU_META_DNODE_OBJECT);
979 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
980 drp = &dr->dr_next;
981 if (dr && dr->dr_txg == tx->tx_txg) {
982 if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID) {
983 /*
984 * If this buffer has already been written out,
985 * we now need to reset its state.
986 */
987 dbuf_unoverride(dr);
988 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
989 db->db_state != DB_NOFILL)
990 arc_buf_thaw(db->db_buf);
991 }
992 mutex_exit(&db->db_mtx);
993 return (dr);
994 }
995
996 /*
997 * Only valid if not already dirty.
998 */
999 ASSERT(dn->dn_object == 0 ||
1000 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1001 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1002
1003 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1004 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1005 dn->dn_phys->dn_nlevels > db->db_level ||
1006 dn->dn_next_nlevels[txgoff] > db->db_level ||
1007 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1008 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1009
1010 /*
1011 * We should only be dirtying in syncing context if it's the
1012 * mos or we're initializing the os or it's a special object.
1013 * However, we are allowed to dirty in syncing context provided
1014 * we already dirtied it in open context. Hence we must make
1015 * this assertion only if we're not already dirty.
1016 */
1017 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1018 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1019 ASSERT(db->db.db_size != 0);
1020
1021 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1022
1023 if (db->db_blkid != DB_BONUS_BLKID) {
1024 /*
1025 * Update the accounting.
1026 * Note: we delay "free accounting" until after we drop
1027 * the db_mtx. This keeps us from grabbing other locks
1028 * (and possibly deadlocking) in bp_get_dsize() while
1029 * also holding the db_mtx.
1030 */
1031 dnode_willuse_space(dn, db->db.db_size, tx);
1032 do_free_accounting = dbuf_block_freeable(db);
1033 }
1034
1035 /*
1036 * If this buffer is dirty in an old transaction group we need
1037 * to make a copy of it so that the changes we make in this
1038 * transaction group won't leak out when we sync the older txg.
1039 */
1040 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1041 if (db->db_level == 0) {
1042 void *data_old = db->db_buf;
1043
1044 if (db->db_state != DB_NOFILL) {
1045 if (db->db_blkid == DB_BONUS_BLKID) {
1046 dbuf_fix_old_data(db, tx->tx_txg);
1047 data_old = db->db.db_data;
1048 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1049 /*
1050 * Release the data buffer from the cache so
1051 * that we can modify it without impacting
1052 * possible other users of this cached data
1053 * block. Note that indirect blocks and
1054 * private objects are not released until the
1055 * syncing state (since they are only modified
1056 * then).
1057 */
1058 arc_release(db->db_buf, db);
1059 dbuf_fix_old_data(db, tx->tx_txg);
1060 data_old = db->db_buf;
1061 }
1062 ASSERT(data_old != NULL);
1063 }
1064 dr->dt.dl.dr_data = data_old;
1065 } else {
1066 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1067 list_create(&dr->dt.di.dr_children,
1068 sizeof (dbuf_dirty_record_t),
1069 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1070 }
1071 dr->dr_dbuf = db;
1072 dr->dr_txg = tx->tx_txg;
1073 dr->dr_next = *drp;
1074 *drp = dr;
1075
1076 /*
1077 * We could have been freed_in_flight between the dbuf_noread
1078 * and dbuf_dirty. We win, as though the dbuf_noread() had
1079 * happened after the free.
1080 */
1081 if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID) {
1082 mutex_enter(&dn->dn_mtx);
1083 dnode_clear_range(dn, db->db_blkid, 1, tx);
1084 mutex_exit(&dn->dn_mtx);
1085 db->db_freed_in_flight = FALSE;
1086 }
1087
1088 /*
1089 * This buffer is now part of this txg
1090 */
1091 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1092 db->db_dirtycnt += 1;
1093 ASSERT3U(db->db_dirtycnt, <=, 3);
1094
1095 mutex_exit(&db->db_mtx);
1096
1097 if (db->db_blkid == DB_BONUS_BLKID) {
1098 mutex_enter(&dn->dn_mtx);
1099 ASSERT(!list_link_active(&dr->dr_dirty_node));
1100 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1101 mutex_exit(&dn->dn_mtx);
1102 dnode_setdirty(dn, tx);
1103 return (dr);
1104 } else if (do_free_accounting) {
1105 blkptr_t *bp = db->db_blkptr;
1106 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1107 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1108 /*
1109 * This is only a guess -- if the dbuf is dirty
1110 * in a previous txg, we don't know how much
1111 * space it will use on disk yet. We should
1112 * really have the struct_rwlock to access
1113 * db_blkptr, but since this is just a guess,
1114 * it's OK if we get an odd answer.
1115 */
1116 dnode_willuse_space(dn, -willfree, tx);
1117 }
1118
1119 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1120 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1121 drop_struct_lock = TRUE;
1122 }
1123
1124 if (db->db_level == 0) {
1125 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1126 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1127 }
1128
1129 if (db->db_level+1 < dn->dn_nlevels) {
1130 dmu_buf_impl_t *parent = db->db_parent;
1131 dbuf_dirty_record_t *di;
1132 int parent_held = FALSE;
1133
1134 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1135 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1136
1137 parent = dbuf_hold_level(dn, db->db_level+1,
1138 db->db_blkid >> epbs, FTAG);
1139 parent_held = TRUE;
1140 }
1141 if (drop_struct_lock)
1142 rw_exit(&dn->dn_struct_rwlock);
1143 ASSERT3U(db->db_level+1, ==, parent->db_level);
1144 di = dbuf_dirty(parent, tx);
1145 if (parent_held)
1146 dbuf_rele(parent, FTAG);
1147
1148 mutex_enter(&db->db_mtx);
1149 /* possible race with dbuf_undirty() */
1150 if (db->db_last_dirty == dr ||
1151 dn->dn_object == DMU_META_DNODE_OBJECT) {
1152 mutex_enter(&di->dt.di.dr_mtx);
1153 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1154 ASSERT(!list_link_active(&dr->dr_dirty_node));
1155 list_insert_tail(&di->dt.di.dr_children, dr);
1156 mutex_exit(&di->dt.di.dr_mtx);
1157 dr->dr_parent = di;
1158 }
1159 mutex_exit(&db->db_mtx);
1160 } else {
1161 ASSERT(db->db_level+1 == dn->dn_nlevels);
1162 ASSERT(db->db_blkid < dn->dn_nblkptr);
1163 ASSERT(db->db_parent == NULL ||
1164 db->db_parent == db->db_dnode->dn_dbuf);
1165 mutex_enter(&dn->dn_mtx);
1166 ASSERT(!list_link_active(&dr->dr_dirty_node));
1167 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1168 mutex_exit(&dn->dn_mtx);
1169 if (drop_struct_lock)
1170 rw_exit(&dn->dn_struct_rwlock);
1171 }
1172
1173 dnode_setdirty(dn, tx);
1174 return (dr);
1175 }
1176
1177 static int
dbuf_undirty(dmu_buf_impl_t * db,dmu_tx_t * tx)1178 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1179 {
1180 dnode_t *dn = db->db_dnode;
1181 uint64_t txg = tx->tx_txg;
1182 dbuf_dirty_record_t *dr, **drp;
1183
1184 ASSERT(txg != 0);
1185 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1186
1187 mutex_enter(&db->db_mtx);
1188 /*
1189 * If this buffer is not dirty, we're done.
1190 */
1191 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1192 if (dr->dr_txg <= txg)
1193 break;
1194 if (dr == NULL || dr->dr_txg < txg) {
1195 mutex_exit(&db->db_mtx);
1196 return (0);
1197 }
1198 ASSERT(dr->dr_txg == txg);
1199 ASSERT(dr->dr_dbuf == db);
1200
1201 /*
1202 * If this buffer is currently held, we cannot undirty
1203 * it, since one of the current holders may be in the
1204 * middle of an update. Note that users of dbuf_undirty()
1205 * should not place a hold on the dbuf before the call.
1206 */
1207 if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
1208 mutex_exit(&db->db_mtx);
1209 /* Make sure we don't toss this buffer at sync phase */
1210 mutex_enter(&dn->dn_mtx);
1211 dnode_clear_range(dn, db->db_blkid, 1, tx);
1212 mutex_exit(&dn->dn_mtx);
1213 return (0);
1214 }
1215
1216 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1217
1218 ASSERT(db->db.db_size != 0);
1219
1220 /* XXX would be nice to fix up dn_towrite_space[] */
1221
1222 *drp = dr->dr_next;
1223
1224 if (dr->dr_parent) {
1225 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1226 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1227 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1228 } else if (db->db_level+1 == dn->dn_nlevels) {
1229 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1230 mutex_enter(&dn->dn_mtx);
1231 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1232 mutex_exit(&dn->dn_mtx);
1233 }
1234
1235 if (db->db_level == 0) {
1236 if (db->db_state != DB_NOFILL) {
1237 dbuf_unoverride(dr);
1238
1239 ASSERT(db->db_buf != NULL);
1240 ASSERT(dr->dt.dl.dr_data != NULL);
1241 if (dr->dt.dl.dr_data != db->db_buf)
1242 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
1243 db) == 1);
1244 }
1245 } else {
1246 ASSERT(db->db_buf != NULL);
1247 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
1248 mutex_destroy(&dr->dt.di.dr_mtx);
1249 list_destroy(&dr->dt.di.dr_children);
1250 }
1251 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1252
1253 ASSERT(db->db_dirtycnt > 0);
1254 db->db_dirtycnt -= 1;
1255
1256 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1257 arc_buf_t *buf = db->db_buf;
1258
1259 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1260 dbuf_set_data(db, NULL);
1261 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1262 dbuf_evict(db);
1263 return (1);
1264 }
1265
1266 mutex_exit(&db->db_mtx);
1267 return (0);
1268 }
1269
1270 __attribute__((__weak__)) void
dmu_buf_will_dirty(dmu_buf_t * db_fake,dmu_tx_t * tx)1271 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx)
1272 {
1273 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1274 dbuf_will_dirty(db, tx);
1275 }
1276
1277 void
dbuf_will_dirty(dmu_buf_impl_t * db,dmu_tx_t * tx)1278 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1279 {
1280 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1281
1282 ASSERT(tx->tx_txg != 0);
1283 ASSERT(!refcount_is_zero(&db->db_holds));
1284
1285 if (RW_WRITE_HELD(&db->db_dnode->dn_struct_rwlock))
1286 rf |= DB_RF_HAVESTRUCT;
1287 (void) dbuf_read(db, NULL, rf);
1288 (void) dbuf_dirty(db, tx);
1289 }
1290
1291 void
dmu_buf_will_not_fill(dmu_buf_t * db_fake,dmu_tx_t * tx)1292 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1293 {
1294 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1295
1296 db->db_state = DB_NOFILL;
1297
1298 dmu_buf_will_fill(db_fake, tx);
1299 }
1300
1301 void
dmu_buf_will_fill(dmu_buf_t * db_fake,dmu_tx_t * tx)1302 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1303 {
1304 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1305
1306 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1307 ASSERT(tx->tx_txg != 0);
1308 ASSERT(db->db_level == 0);
1309 ASSERT(!refcount_is_zero(&db->db_holds));
1310
1311 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1312 dmu_tx_private_ok(tx));
1313
1314 dbuf_noread(db);
1315 (void) dbuf_dirty(db, tx);
1316 }
1317
1318 __attribute__((__weak__)) void
dmu_buf_fill_done(dmu_buf_t * db_fake,dmu_tx_t * tx)1319 dmu_buf_fill_done(dmu_buf_t *db_fake, dmu_tx_t *tx)
1320 {
1321 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1322 dbuf_fill_done(db, tx);
1323 }
1324
1325 /* ARGSUSED */
1326 void
dbuf_fill_done(dmu_buf_impl_t * db,dmu_tx_t * tx)1327 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1328 {
1329 mutex_enter(&db->db_mtx);
1330 DBUF_VERIFY(db);
1331
1332 if (db->db_state == DB_FILL) {
1333 if (db->db_level == 0 && db->db_freed_in_flight) {
1334 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1335 /* we were freed while filling */
1336 /* XXX dbuf_undirty? */
1337 bzero(db->db.db_data, db->db.db_size);
1338 db->db_freed_in_flight = FALSE;
1339 }
1340 db->db_state = DB_CACHED;
1341 cv_broadcast(&db->db_changed);
1342 }
1343 mutex_exit(&db->db_mtx);
1344 }
1345
1346 /*
1347 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1348 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1349 */
1350 void
dbuf_assign_arcbuf(dmu_buf_impl_t * db,arc_buf_t * buf,dmu_tx_t * tx)1351 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1352 {
1353 ASSERT(!refcount_is_zero(&db->db_holds));
1354 ASSERT(db->db_dnode->dn_object != DMU_META_DNODE_OBJECT);
1355 ASSERT(db->db_blkid != DB_BONUS_BLKID);
1356 ASSERT(db->db_level == 0);
1357 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1358 ASSERT(buf != NULL);
1359 ASSERT(arc_buf_size(buf) == db->db.db_size);
1360 ASSERT(tx->tx_txg != 0);
1361
1362 arc_return_buf(buf, db);
1363 ASSERT(arc_released(buf));
1364
1365 mutex_enter(&db->db_mtx);
1366
1367 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1368 cv_wait(&db->db_changed, &db->db_mtx);
1369
1370 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1371
1372 if (db->db_state == DB_CACHED &&
1373 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1374 mutex_exit(&db->db_mtx);
1375 (void) dbuf_dirty(db, tx);
1376 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1377 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1378 xuio_stat_wbuf_copied();
1379 return;
1380 }
1381
1382 xuio_stat_wbuf_nocopy();
1383 if (db->db_state == DB_CACHED) {
1384 dbuf_dirty_record_t *dr = db->db_last_dirty;
1385
1386 ASSERT(db->db_buf != NULL);
1387 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1388 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1389 if (!arc_released(db->db_buf)) {
1390 ASSERT(dr->dt.dl.dr_override_state ==
1391 DR_OVERRIDDEN);
1392 arc_release(db->db_buf, db);
1393 }
1394 dr->dt.dl.dr_data = buf;
1395 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
1396 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1397 arc_release(db->db_buf, db);
1398 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
1399 }
1400 db->db_buf = NULL;
1401 }
1402 ASSERT(db->db_buf == NULL);
1403 dbuf_set_data(db, buf);
1404 db->db_state = DB_FILL;
1405 mutex_exit(&db->db_mtx);
1406 (void) dbuf_dirty(db, tx);
1407 dbuf_fill_done(db, tx);
1408 }
1409
1410 /*
1411 * "Clear" the contents of this dbuf. This will mark the dbuf
1412 * EVICTING and clear *most* of its references. Unfortunetely,
1413 * when we are not holding the dn_dbufs_mtx, we can't clear the
1414 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1415 * in this case. For callers from the DMU we will usually see:
1416 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1417 * For the arc callback, we will usually see:
1418 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1419 * Sometimes, though, we will get a mix of these two:
1420 * DMU: dbuf_clear()->arc_buf_evict()
1421 * ARC: dbuf_do_evict()->dbuf_destroy()
1422 */
1423 void
dbuf_clear(dmu_buf_impl_t * db)1424 dbuf_clear(dmu_buf_impl_t *db)
1425 {
1426 dnode_t *dn = db->db_dnode;
1427 dmu_buf_impl_t *parent = db->db_parent;
1428 dmu_buf_impl_t *dndb = dn->dn_dbuf;
1429 int dbuf_gone = FALSE;
1430
1431 ASSERT(MUTEX_HELD(&db->db_mtx));
1432 ASSERT(refcount_is_zero(&db->db_holds));
1433
1434 dbuf_evict_user(db);
1435
1436 if (db->db_state == DB_CACHED) {
1437 ASSERT(db->db.db_data != NULL);
1438 if (db->db_blkid == DB_BONUS_BLKID) {
1439 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1440 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1441 }
1442 db->db.db_data = NULL;
1443 db->db_state = DB_UNCACHED;
1444 }
1445
1446 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1447 ASSERT(db->db_data_pending == NULL);
1448
1449 db->db_state = DB_EVICTING;
1450 db->db_blkptr = NULL;
1451
1452 if (db->db_blkid != DB_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1453 list_remove(&dn->dn_dbufs, db);
1454 dnode_rele(dn, db);
1455 db->db_dnode = NULL;
1456 }
1457
1458 if (db->db_buf)
1459 dbuf_gone = arc_buf_evict(db->db_buf);
1460
1461 if (!dbuf_gone)
1462 mutex_exit(&db->db_mtx);
1463
1464 /*
1465 * If this dbuf is referened from an indirect dbuf,
1466 * decrement the ref count on the indirect dbuf.
1467 */
1468 if (parent && parent != dndb)
1469 dbuf_rele(parent, db);
1470 }
1471
1472 static int
dbuf_findbp(dnode_t * dn,int level,uint64_t blkid,int fail_sparse,dmu_buf_impl_t ** parentp,blkptr_t ** bpp)1473 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1474 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1475 {
1476 int nlevels, epbs;
1477
1478 *parentp = NULL;
1479 *bpp = NULL;
1480
1481 ASSERT(blkid != DB_BONUS_BLKID);
1482
1483 if (dn->dn_phys->dn_nlevels == 0)
1484 nlevels = 1;
1485 else
1486 nlevels = dn->dn_phys->dn_nlevels;
1487
1488 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1489
1490 ASSERT3U(level * epbs, <, 64);
1491 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1492 if (level >= nlevels ||
1493 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1494 /* the buffer has no parent yet */
1495 return (ENOENT);
1496 } else if (level < nlevels-1) {
1497 /* this block is referenced from an indirect block */
1498 int err = dbuf_hold_impl(dn, level+1,
1499 blkid >> epbs, fail_sparse, NULL, parentp);
1500 if (err)
1501 return (err);
1502 err = dbuf_read(*parentp, NULL,
1503 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1504 if (err) {
1505 dbuf_rele(*parentp, NULL);
1506 *parentp = NULL;
1507 return (err);
1508 }
1509 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1510 (blkid & ((1ULL << epbs) - 1));
1511 return (0);
1512 } else {
1513 /* the block is referenced from the dnode */
1514 ASSERT3U(level, ==, nlevels-1);
1515 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1516 blkid < dn->dn_phys->dn_nblkptr);
1517 if (dn->dn_dbuf) {
1518 dbuf_add_ref(dn->dn_dbuf, NULL);
1519 *parentp = dn->dn_dbuf;
1520 }
1521 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1522 return (0);
1523 }
1524 }
1525
1526 static dmu_buf_impl_t *
dbuf_create(dnode_t * dn,uint8_t level,uint64_t blkid,dmu_buf_impl_t * parent,blkptr_t * blkptr)1527 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1528 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1529 {
1530 objset_t *os = dn->dn_objset;
1531 dmu_buf_impl_t *db, *odb;
1532
1533 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1534 ASSERT(dn->dn_type != DMU_OT_NONE);
1535
1536 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1537
1538 db->db_objset = os;
1539 db->db.db_object = dn->dn_object;
1540 db->db_level = level;
1541 db->db_blkid = blkid;
1542 db->db_last_dirty = NULL;
1543 db->db_dirtycnt = 0;
1544 db->db_dnode = dn;
1545 db->db_parent = parent;
1546 db->db_blkptr = blkptr;
1547
1548 db->db_user_ptr = NULL;
1549 db->db_user_data_ptr_ptr = NULL;
1550 db->db_evict_func = NULL;
1551 db->db_immediate_evict = 0;
1552 db->db_freed_in_flight = 0;
1553
1554 if (blkid == DB_BONUS_BLKID) {
1555 ASSERT3P(parent, ==, dn->dn_dbuf);
1556 db->db.db_size = DN_MAX_BONUSLEN -
1557 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1558 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1559 db->db.db_offset = DB_BONUS_BLKID;
1560 db->db_state = DB_UNCACHED;
1561 /* the bonus dbuf is not placed in the hash table */
1562 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1563 return (db);
1564 } else {
1565 int blocksize =
1566 db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz;
1567 db->db.db_size = blocksize;
1568 db->db.db_offset = db->db_blkid * blocksize;
1569 }
1570
1571 /*
1572 * Hold the dn_dbufs_mtx while we get the new dbuf
1573 * in the hash table *and* added to the dbufs list.
1574 * This prevents a possible deadlock with someone
1575 * trying to look up this dbuf before its added to the
1576 * dn_dbufs list.
1577 */
1578 mutex_enter(&dn->dn_dbufs_mtx);
1579 db->db_state = DB_EVICTING;
1580 if ((odb = dbuf_hash_insert(db)) != NULL) {
1581 /* someone else inserted it first */
1582 kmem_cache_free(dbuf_cache, db);
1583 mutex_exit(&dn->dn_dbufs_mtx);
1584 return (odb);
1585 }
1586 list_insert_head(&dn->dn_dbufs, db);
1587 db->db_state = DB_UNCACHED;
1588 mutex_exit(&dn->dn_dbufs_mtx);
1589 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1590
1591 if (parent && parent != dn->dn_dbuf)
1592 dbuf_add_ref(parent, db);
1593
1594 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1595 refcount_count(&dn->dn_holds) > 0);
1596 (void) refcount_add(&dn->dn_holds, db);
1597
1598 dprintf_dbuf(db, "db=%p\n", db);
1599
1600 return (db);
1601 }
1602
1603 static int
dbuf_do_evict(void * private)1604 dbuf_do_evict(void *private)
1605 {
1606 arc_buf_t *buf = private;
1607 dmu_buf_impl_t *db = buf->b_private;
1608
1609 if (!MUTEX_HELD(&db->db_mtx))
1610 mutex_enter(&db->db_mtx);
1611
1612 ASSERT(refcount_is_zero(&db->db_holds));
1613
1614 if (db->db_state != DB_EVICTING) {
1615 ASSERT(db->db_state == DB_CACHED);
1616 DBUF_VERIFY(db);
1617 db->db_buf = NULL;
1618 dbuf_evict(db);
1619 } else {
1620 mutex_exit(&db->db_mtx);
1621 dbuf_destroy(db);
1622 }
1623 return (0);
1624 }
1625
1626 static void
dbuf_destroy(dmu_buf_impl_t * db)1627 dbuf_destroy(dmu_buf_impl_t *db)
1628 {
1629 ASSERT(refcount_is_zero(&db->db_holds));
1630
1631 if (db->db_blkid != DB_BONUS_BLKID) {
1632 /*
1633 * If this dbuf is still on the dn_dbufs list,
1634 * remove it from that list.
1635 */
1636 if (db->db_dnode) {
1637 dnode_t *dn = db->db_dnode;
1638
1639 mutex_enter(&dn->dn_dbufs_mtx);
1640 list_remove(&dn->dn_dbufs, db);
1641 mutex_exit(&dn->dn_dbufs_mtx);
1642
1643 dnode_rele(dn, db);
1644 db->db_dnode = NULL;
1645 }
1646 dbuf_hash_remove(db);
1647 }
1648 db->db_parent = NULL;
1649 db->db_buf = NULL;
1650
1651 ASSERT(!list_link_active(&db->db_link));
1652 ASSERT(db->db.db_data == NULL);
1653 ASSERT(db->db_hash_next == NULL);
1654 ASSERT(db->db_blkptr == NULL);
1655 ASSERT(db->db_data_pending == NULL);
1656
1657 kmem_cache_free(dbuf_cache, db);
1658 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1659 }
1660
1661 void
dbuf_prefetch(dnode_t * dn,uint64_t blkid)1662 dbuf_prefetch(dnode_t *dn, uint64_t blkid)
1663 {
1664 dmu_buf_impl_t *db = NULL;
1665 blkptr_t *bp = NULL;
1666
1667 ASSERT(blkid != DB_BONUS_BLKID);
1668 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1669
1670 if (dnode_block_freed(dn, blkid))
1671 return;
1672
1673 /* dbuf_find() returns with db_mtx held */
1674 if (db = dbuf_find(dn, 0, blkid)) {
1675 if (refcount_count(&db->db_holds) > 0) {
1676 /*
1677 * This dbuf is active. We assume that it is
1678 * already CACHED, or else about to be either
1679 * read or filled.
1680 */
1681 mutex_exit(&db->db_mtx);
1682 return;
1683 }
1684 mutex_exit(&db->db_mtx);
1685 db = NULL;
1686 }
1687
1688 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1689 if (bp && !BP_IS_HOLE(bp)) {
1690 arc_buf_t *pbuf;
1691 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1692 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1693 zbookmark_t zb;
1694
1695 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1696 dn->dn_object, 0, blkid);
1697
1698 if (db)
1699 pbuf = db->db_buf;
1700 else
1701 pbuf = dn->dn_objset->os_phys_buf;
1702
1703 (void) arc_read(NULL, dn->dn_objset->os_spa,
1704 bp, pbuf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
1705 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1706 &aflags, &zb);
1707 }
1708 if (db)
1709 dbuf_rele(db, NULL);
1710 }
1711 }
1712
1713 /*
1714 * Returns with db_holds incremented, and db_mtx not held.
1715 * Note: dn_struct_rwlock must be held.
1716 */
1717 int
dbuf_hold_impl(dnode_t * dn,uint8_t level,uint64_t blkid,int fail_sparse,void * tag,dmu_buf_impl_t ** dbp)1718 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1719 void *tag, dmu_buf_impl_t **dbp)
1720 {
1721 dmu_buf_impl_t *db, *parent = NULL;
1722
1723 ASSERT(blkid != DB_BONUS_BLKID);
1724 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1725 ASSERT3U(dn->dn_nlevels, >, level);
1726
1727 *dbp = NULL;
1728 top:
1729 /* dbuf_find() returns with db_mtx held */
1730 db = dbuf_find(dn, level, blkid);
1731
1732 if (db == NULL) {
1733 blkptr_t *bp = NULL;
1734 int err;
1735
1736 ASSERT3P(parent, ==, NULL);
1737 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1738 if (fail_sparse) {
1739 if (err == 0 && bp && BP_IS_HOLE(bp))
1740 err = ENOENT;
1741 if (err) {
1742 if (parent)
1743 dbuf_rele(parent, NULL);
1744 return (err);
1745 }
1746 }
1747 if (err && err != ENOENT)
1748 return (err);
1749 db = dbuf_create(dn, level, blkid, parent, bp);
1750 }
1751
1752 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1753 arc_buf_add_ref(db->db_buf, db);
1754 if (db->db_buf->b_data == NULL) {
1755 dbuf_clear(db);
1756 if (parent) {
1757 dbuf_rele(parent, NULL);
1758 parent = NULL;
1759 }
1760 goto top;
1761 }
1762 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1763 }
1764
1765 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1766
1767 /*
1768 * If this buffer is currently syncing out, and we are are
1769 * still referencing it from db_data, we need to make a copy
1770 * of it in case we decide we want to dirty it again in this txg.
1771 */
1772 if (db->db_level == 0 && db->db_blkid != DB_BONUS_BLKID &&
1773 dn->dn_object != DMU_META_DNODE_OBJECT &&
1774 db->db_state == DB_CACHED && db->db_data_pending) {
1775 dbuf_dirty_record_t *dr = db->db_data_pending;
1776
1777 if (dr->dt.dl.dr_data == db->db_buf) {
1778 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1779
1780 dbuf_set_data(db,
1781 arc_buf_alloc(db->db_dnode->dn_objset->os_spa,
1782 db->db.db_size, db, type));
1783 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1784 db->db.db_size);
1785 }
1786 }
1787
1788 (void) refcount_add(&db->db_holds, tag);
1789 dbuf_update_data(db);
1790 DBUF_VERIFY(db);
1791 mutex_exit(&db->db_mtx);
1792
1793 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1794 if (parent)
1795 dbuf_rele(parent, NULL);
1796
1797 ASSERT3P(db->db_dnode, ==, dn);
1798 ASSERT3U(db->db_blkid, ==, blkid);
1799 ASSERT3U(db->db_level, ==, level);
1800 *dbp = db;
1801
1802 return (0);
1803 }
1804
1805 dmu_buf_impl_t *
dbuf_hold(dnode_t * dn,uint64_t blkid,void * tag)1806 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1807 {
1808 dmu_buf_impl_t *db;
1809 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1810 return (err ? NULL : db);
1811 }
1812
1813 dmu_buf_impl_t *
dbuf_hold_level(dnode_t * dn,int level,uint64_t blkid,void * tag)1814 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1815 {
1816 dmu_buf_impl_t *db;
1817 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1818 return (err ? NULL : db);
1819 }
1820
1821 void
dbuf_create_bonus(dnode_t * dn)1822 dbuf_create_bonus(dnode_t *dn)
1823 {
1824 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1825
1826 ASSERT(dn->dn_bonus == NULL);
1827 dn->dn_bonus = dbuf_create(dn, 0, DB_BONUS_BLKID, dn->dn_dbuf, NULL);
1828 }
1829
1830 __attribute__((__weak__)) void
dmu_buf_add_ref(dmu_buf_t * db_fake,void * tag)1831 dmu_buf_add_ref(dmu_buf_t *db_fake, void *tag)
1832 {
1833 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1834 dbuf_add_ref(db, tag);
1835 }
1836
1837 void
dbuf_add_ref(dmu_buf_impl_t * db,void * tag)1838 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
1839 {
1840 int64_t holds = refcount_add(&db->db_holds, tag);
1841 ASSERT(holds > 1);
1842 }
1843
1844 __attribute__((__weak__)) void
dmu_buf_rele(dmu_buf_t * db_fake,void * tag)1845 dmu_buf_rele(dmu_buf_t *db_fake, void *tag)
1846 {
1847 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1848 dbuf_rele(db, tag);
1849 }
1850
1851 void
dbuf_rele(dmu_buf_impl_t * db,void * tag)1852 dbuf_rele(dmu_buf_impl_t *db, void *tag)
1853 {
1854 mutex_enter(&db->db_mtx);
1855 dbuf_rele_and_unlock(db, tag);
1856 }
1857
1858 /*
1859 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
1860 * db_dirtycnt and db_holds to be updated atomically.
1861 */
1862 void
dbuf_rele_and_unlock(dmu_buf_impl_t * db,void * tag)1863 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
1864 {
1865 int64_t holds;
1866
1867 ASSERT(MUTEX_HELD(&db->db_mtx));
1868 DBUF_VERIFY(db);
1869
1870 holds = refcount_remove(&db->db_holds, tag);
1871 ASSERT(holds >= 0);
1872
1873 /*
1874 * We can't freeze indirects if there is a possibility that they
1875 * may be modified in the current syncing context.
1876 */
1877 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
1878 arc_buf_freeze(db->db_buf);
1879
1880 if (holds == db->db_dirtycnt &&
1881 db->db_level == 0 && db->db_immediate_evict)
1882 dbuf_evict_user(db);
1883
1884 if (holds == 0) {
1885 if (db->db_blkid == DB_BONUS_BLKID) {
1886 mutex_exit(&db->db_mtx);
1887 dnode_rele(db->db_dnode, db);
1888 } else if (db->db_buf == NULL) {
1889 /*
1890 * This is a special case: we never associated this
1891 * dbuf with any data allocated from the ARC.
1892 */
1893 ASSERT(db->db_state == DB_UNCACHED ||
1894 db->db_state == DB_NOFILL);
1895 dbuf_evict(db);
1896 } else if (arc_released(db->db_buf)) {
1897 arc_buf_t *buf = db->db_buf;
1898 /*
1899 * This dbuf has anonymous data associated with it.
1900 */
1901 dbuf_set_data(db, NULL);
1902 VERIFY(arc_buf_remove_ref(buf, db) == 1);
1903 dbuf_evict(db);
1904 } else {
1905 VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
1906 if (!DBUF_IS_CACHEABLE(db))
1907 dbuf_clear(db);
1908 else
1909 mutex_exit(&db->db_mtx);
1910 }
1911 } else {
1912 mutex_exit(&db->db_mtx);
1913 }
1914 }
1915
1916 __attribute__((__weak__)) uint64_t
dmu_buf_refcount(dmu_buf_t * db_fake)1917 dmu_buf_refcount(dmu_buf_t *db_fake)
1918 {
1919 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1920 return dbuf_refcount(db);
1921 }
1922
1923 uint64_t
dbuf_refcount(dmu_buf_impl_t * db)1924 dbuf_refcount(dmu_buf_impl_t *db)
1925 {
1926 return (refcount_count(&db->db_holds));
1927 }
1928
1929 void *
dmu_buf_set_user(dmu_buf_t * db_fake,void * user_ptr,void * user_data_ptr_ptr,dmu_buf_evict_func_t * evict_func)1930 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
1931 dmu_buf_evict_func_t *evict_func)
1932 {
1933 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
1934 user_data_ptr_ptr, evict_func));
1935 }
1936
1937 void *
dmu_buf_set_user_ie(dmu_buf_t * db_fake,void * user_ptr,void * user_data_ptr_ptr,dmu_buf_evict_func_t * evict_func)1938 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
1939 dmu_buf_evict_func_t *evict_func)
1940 {
1941 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1942
1943 db->db_immediate_evict = TRUE;
1944 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
1945 user_data_ptr_ptr, evict_func));
1946 }
1947
1948 void *
dmu_buf_update_user(dmu_buf_t * db_fake,void * old_user_ptr,void * user_ptr,void * user_data_ptr_ptr,dmu_buf_evict_func_t * evict_func)1949 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
1950 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
1951 {
1952 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1953 ASSERT(db->db_level == 0);
1954
1955 ASSERT((user_ptr == NULL) == (evict_func == NULL));
1956
1957 mutex_enter(&db->db_mtx);
1958
1959 if (db->db_user_ptr == old_user_ptr) {
1960 db->db_user_ptr = user_ptr;
1961 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
1962 db->db_evict_func = evict_func;
1963
1964 dbuf_update_data(db);
1965 } else {
1966 old_user_ptr = db->db_user_ptr;
1967 }
1968
1969 mutex_exit(&db->db_mtx);
1970 return (old_user_ptr);
1971 }
1972
1973 void *
dmu_buf_get_user(dmu_buf_t * db_fake)1974 dmu_buf_get_user(dmu_buf_t *db_fake)
1975 {
1976 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1977 ASSERT(!refcount_is_zero(&db->db_holds));
1978
1979 return (db->db_user_ptr);
1980 }
1981
1982 boolean_t
dmu_buf_freeable(dmu_buf_t * dbuf)1983 dmu_buf_freeable(dmu_buf_t *dbuf)
1984 {
1985 boolean_t res = B_FALSE;
1986 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
1987
1988 if (db->db_blkptr)
1989 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
1990 db->db_blkptr->blk_birth);
1991
1992 return (res);
1993 }
1994
1995 static void
dbuf_check_blkptr(dnode_t * dn,dmu_buf_impl_t * db)1996 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
1997 {
1998 /* ASSERT(dmu_tx_is_syncing(tx) */
1999 ASSERT(MUTEX_HELD(&db->db_mtx));
2000
2001 if (db->db_blkptr != NULL)
2002 return;
2003
2004 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2005 /*
2006 * This buffer was allocated at a time when there was
2007 * no available blkptrs from the dnode, or it was
2008 * inappropriate to hook it in (i.e., nlevels mis-match).
2009 */
2010 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2011 ASSERT(db->db_parent == NULL);
2012 db->db_parent = dn->dn_dbuf;
2013 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2014 DBUF_VERIFY(db);
2015 } else {
2016 dmu_buf_impl_t *parent = db->db_parent;
2017 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2018
2019 ASSERT(dn->dn_phys->dn_nlevels > 1);
2020 if (parent == NULL) {
2021 mutex_exit(&db->db_mtx);
2022 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2023 (void) dbuf_hold_impl(dn, db->db_level+1,
2024 db->db_blkid >> epbs, FALSE, db, &parent);
2025 rw_exit(&dn->dn_struct_rwlock);
2026 mutex_enter(&db->db_mtx);
2027 db->db_parent = parent;
2028 }
2029 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2030 (db->db_blkid & ((1ULL << epbs) - 1));
2031 DBUF_VERIFY(db);
2032 }
2033 }
2034
2035 static void
dbuf_sync_indirect(dbuf_dirty_record_t * dr,dmu_tx_t * tx)2036 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2037 {
2038 dmu_buf_impl_t *db = dr->dr_dbuf;
2039 dnode_t *dn = db->db_dnode;
2040 zio_t *zio;
2041
2042 ASSERT(dmu_tx_is_syncing(tx));
2043
2044 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2045
2046 mutex_enter(&db->db_mtx);
2047
2048 ASSERT(db->db_level > 0);
2049 DBUF_VERIFY(db);
2050
2051 if (db->db_buf == NULL) {
2052 mutex_exit(&db->db_mtx);
2053 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2054 mutex_enter(&db->db_mtx);
2055 }
2056 ASSERT3U(db->db_state, ==, DB_CACHED);
2057 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2058 ASSERT(db->db_buf != NULL);
2059
2060 dbuf_check_blkptr(dn, db);
2061
2062 db->db_data_pending = dr;
2063
2064 mutex_exit(&db->db_mtx);
2065 dbuf_write(dr, db->db_buf, tx);
2066
2067 zio = dr->dr_zio;
2068 mutex_enter(&dr->dt.di.dr_mtx);
2069 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2070 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2071 mutex_exit(&dr->dt.di.dr_mtx);
2072 zio_nowait(zio);
2073 }
2074
2075 static void
dbuf_sync_leaf(dbuf_dirty_record_t * dr,dmu_tx_t * tx)2076 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2077 {
2078 arc_buf_t **datap = &dr->dt.dl.dr_data;
2079 dmu_buf_impl_t *db = dr->dr_dbuf;
2080 dnode_t *dn = db->db_dnode;
2081 objset_t *os = dn->dn_objset;
2082 uint64_t txg = tx->tx_txg;
2083
2084 ASSERT(dmu_tx_is_syncing(tx));
2085
2086 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2087
2088 mutex_enter(&db->db_mtx);
2089 /*
2090 * To be synced, we must be dirtied. But we
2091 * might have been freed after the dirty.
2092 */
2093 if (db->db_state == DB_UNCACHED) {
2094 /* This buffer has been freed since it was dirtied */
2095 ASSERT(db->db.db_data == NULL);
2096 } else if (db->db_state == DB_FILL) {
2097 /* This buffer was freed and is now being re-filled */
2098 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2099 } else {
2100 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2101 }
2102 DBUF_VERIFY(db);
2103
2104 /*
2105 * If this is a bonus buffer, simply copy the bonus data into the
2106 * dnode. It will be written out when the dnode is synced (and it
2107 * will be synced, since it must have been dirty for dbuf_sync to
2108 * be called).
2109 */
2110 if (db->db_blkid == DB_BONUS_BLKID) {
2111 dbuf_dirty_record_t **drp;
2112
2113 ASSERT(*datap != NULL);
2114 ASSERT3U(db->db_level, ==, 0);
2115 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2116 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2117 if (*datap != db->db.db_data) {
2118 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2119 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2120 }
2121 db->db_data_pending = NULL;
2122 drp = &db->db_last_dirty;
2123 while (*drp != dr)
2124 drp = &(*drp)->dr_next;
2125 ASSERT(dr->dr_next == NULL);
2126 ASSERT(dr->dr_dbuf == db);
2127 *drp = dr->dr_next;
2128 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2129 ASSERT(db->db_dirtycnt > 0);
2130 db->db_dirtycnt -= 1;
2131 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2132 return;
2133 }
2134
2135 /*
2136 * This function may have dropped the db_mtx lock allowing a dmu_sync
2137 * operation to sneak in. As a result, we need to ensure that we
2138 * don't check the dr_override_state until we have returned from
2139 * dbuf_check_blkptr.
2140 */
2141 dbuf_check_blkptr(dn, db);
2142
2143 /*
2144 * If this buffer is in the middle of an immdiate write,
2145 * wait for the synchronous IO to complete.
2146 */
2147 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2148 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2149 cv_wait(&db->db_changed, &db->db_mtx);
2150 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2151 }
2152
2153 if (db->db_state != DB_NOFILL &&
2154 dn->dn_object != DMU_META_DNODE_OBJECT &&
2155 refcount_count(&db->db_holds) > 1 &&
2156 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2157 *datap == db->db_buf) {
2158 /*
2159 * If this buffer is currently "in use" (i.e., there
2160 * are active holds and db_data still references it),
2161 * then make a copy before we start the write so that
2162 * any modifications from the open txg will not leak
2163 * into this write.
2164 *
2165 * NOTE: this copy does not need to be made for
2166 * objects only modified in the syncing context (e.g.
2167 * DNONE_DNODE blocks).
2168 */
2169 int blksz = arc_buf_size(*datap);
2170 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2171 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2172 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2173 }
2174 db->db_data_pending = dr;
2175
2176 mutex_exit(&db->db_mtx);
2177
2178 dbuf_write(dr, *datap, tx);
2179
2180 ASSERT(!list_link_active(&dr->dr_dirty_node));
2181 if (dn->dn_object == DMU_META_DNODE_OBJECT)
2182 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2183 else
2184 zio_nowait(dr->dr_zio);
2185 }
2186
2187 void
dbuf_sync_list(list_t * list,dmu_tx_t * tx)2188 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2189 {
2190 dbuf_dirty_record_t *dr;
2191
2192 while (dr = list_head(list)) {
2193 if (dr->dr_zio != NULL) {
2194 /*
2195 * If we find an already initialized zio then we
2196 * are processing the meta-dnode, and we have finished.
2197 * The dbufs for all dnodes are put back on the list
2198 * during processing, so that we can zio_wait()
2199 * these IOs after initiating all child IOs.
2200 */
2201 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2202 DMU_META_DNODE_OBJECT);
2203 break;
2204 }
2205 list_remove(list, dr);
2206 if (dr->dr_dbuf->db_level > 0)
2207 dbuf_sync_indirect(dr, tx);
2208 else
2209 dbuf_sync_leaf(dr, tx);
2210 }
2211 }
2212
2213 /* ARGSUSED */
2214 static void
dbuf_write_ready(zio_t * zio,arc_buf_t * buf,void * vdb)2215 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2216 {
2217 dmu_buf_impl_t *db = vdb;
2218 blkptr_t *bp = zio->io_bp;
2219 blkptr_t *bp_orig = &zio->io_bp_orig;
2220 dnode_t *dn = db->db_dnode;
2221 spa_t *spa = zio->io_spa;
2222 int64_t delta;
2223 uint64_t fill = 0;
2224 int i;
2225
2226 ASSERT(db->db_blkptr == bp);
2227
2228 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2229 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2230 zio->io_prev_space_delta = delta;
2231
2232 if (BP_IS_HOLE(bp)) {
2233 ASSERT(bp->blk_fill == 0);
2234 return;
2235 }
2236
2237 ASSERT(BP_GET_TYPE(bp) == dn->dn_type);
2238 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2239
2240 mutex_enter(&db->db_mtx);
2241
2242 if (db->db_level == 0) {
2243 mutex_enter(&dn->dn_mtx);
2244 if (db->db_blkid > dn->dn_phys->dn_maxblkid)
2245 dn->dn_phys->dn_maxblkid = db->db_blkid;
2246 mutex_exit(&dn->dn_mtx);
2247
2248 if (dn->dn_type == DMU_OT_DNODE) {
2249 dnode_phys_t *dnp = db->db.db_data;
2250 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2251 i--, dnp++) {
2252 if (dnp->dn_type != DMU_OT_NONE)
2253 fill++;
2254 }
2255 } else {
2256 fill = 1;
2257 }
2258 } else {
2259 blkptr_t *ibp = db->db.db_data;
2260 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2261 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2262 if (BP_IS_HOLE(ibp))
2263 continue;
2264 fill += ibp->blk_fill;
2265 }
2266 }
2267
2268 bp->blk_fill = fill;
2269
2270 mutex_exit(&db->db_mtx);
2271 }
2272
2273 /* ARGSUSED */
2274 static void
dbuf_write_done(zio_t * zio,arc_buf_t * buf,void * vdb)2275 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2276 {
2277 dmu_buf_impl_t *db = vdb;
2278 blkptr_t *bp = zio->io_bp;
2279 blkptr_t *bp_orig = &zio->io_bp_orig;
2280 dnode_t *dn = db->db_dnode;
2281 objset_t *os = dn->dn_objset;
2282 uint64_t txg = zio->io_txg;
2283 dbuf_dirty_record_t **drp, *dr;
2284
2285 ASSERT3U(zio->io_error, ==, 0);
2286 ASSERT(db->db_blkptr == bp);
2287
2288 if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
2289 ASSERT(BP_EQUAL(bp, bp_orig));
2290 } else {
2291 dsl_dataset_t *ds = os->os_dsl_dataset;
2292 dmu_tx_t *tx = os->os_synctx;
2293
2294 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2295 dsl_dataset_block_born(ds, bp, tx);
2296 }
2297
2298 mutex_enter(&db->db_mtx);
2299
2300 DBUF_VERIFY(db);
2301
2302 drp = &db->db_last_dirty;
2303 while ((dr = *drp) != db->db_data_pending)
2304 drp = &dr->dr_next;
2305 ASSERT(!list_link_active(&dr->dr_dirty_node));
2306 ASSERT(dr->dr_txg == txg);
2307 ASSERT(dr->dr_dbuf == db);
2308 ASSERT(dr->dr_next == NULL);
2309 *drp = dr->dr_next;
2310
2311 if (db->db_level == 0) {
2312 ASSERT(db->db_blkid != DB_BONUS_BLKID);
2313 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2314 if (db->db_state != DB_NOFILL) {
2315 if (dr->dt.dl.dr_data != db->db_buf)
2316 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2317 db) == 1);
2318 else if (!arc_released(db->db_buf))
2319 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2320 }
2321 } else {
2322 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2323 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2324 if (!BP_IS_HOLE(db->db_blkptr)) {
2325 int epbs =
2326 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2327 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2328 db->db.db_size);
2329 ASSERT3U(dn->dn_phys->dn_maxblkid
2330 >> (db->db_level * epbs), >=, db->db_blkid);
2331 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2332 }
2333 mutex_destroy(&dr->dt.di.dr_mtx);
2334 list_destroy(&dr->dt.di.dr_children);
2335 }
2336 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2337
2338 cv_broadcast(&db->db_changed);
2339 ASSERT(db->db_dirtycnt > 0);
2340 db->db_dirtycnt -= 1;
2341 db->db_data_pending = NULL;
2342 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2343 }
2344
2345 static void
dbuf_write_nofill_ready(zio_t * zio)2346 dbuf_write_nofill_ready(zio_t *zio)
2347 {
2348 dbuf_write_ready(zio, NULL, zio->io_private);
2349 }
2350
2351 static void
dbuf_write_nofill_done(zio_t * zio)2352 dbuf_write_nofill_done(zio_t *zio)
2353 {
2354 dbuf_write_done(zio, NULL, zio->io_private);
2355 }
2356
2357 static void
dbuf_write_override_ready(zio_t * zio)2358 dbuf_write_override_ready(zio_t *zio)
2359 {
2360 dbuf_dirty_record_t *dr = zio->io_private;
2361 dmu_buf_impl_t *db = dr->dr_dbuf;
2362
2363 dbuf_write_ready(zio, NULL, db);
2364 }
2365
2366 static void
dbuf_write_override_done(zio_t * zio)2367 dbuf_write_override_done(zio_t *zio)
2368 {
2369 dbuf_dirty_record_t *dr = zio->io_private;
2370 dmu_buf_impl_t *db = dr->dr_dbuf;
2371 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2372
2373 mutex_enter(&db->db_mtx);
2374 if (!BP_EQUAL(zio->io_bp, obp)) {
2375 if (!BP_IS_HOLE(obp))
2376 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2377 arc_release(dr->dt.dl.dr_data, db);
2378 }
2379 mutex_exit(&db->db_mtx);
2380
2381 dbuf_write_done(zio, NULL, db);
2382 }
2383
2384 static void
dbuf_write(dbuf_dirty_record_t * dr,arc_buf_t * data,dmu_tx_t * tx)2385 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2386 {
2387 dmu_buf_impl_t *db = dr->dr_dbuf;
2388 dnode_t *dn = db->db_dnode;
2389 objset_t *os = dn->dn_objset;
2390 dmu_buf_impl_t *parent = db->db_parent;
2391 uint64_t txg = tx->tx_txg;
2392 zbookmark_t zb;
2393 zio_prop_t zp;
2394 zio_t *zio;
2395
2396 if (db->db_state != DB_NOFILL) {
2397 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2398 /*
2399 * Private object buffers are released here rather
2400 * than in dbuf_dirty() since they are only modified
2401 * in the syncing context and we don't want the
2402 * overhead of making multiple copies of the data.
2403 */
2404 if (BP_IS_HOLE(db->db_blkptr)) {
2405 arc_buf_thaw(data);
2406 } else {
2407 arc_release(data, db);
2408 }
2409 }
2410 }
2411
2412 if (parent != dn->dn_dbuf) {
2413 ASSERT(parent && parent->db_data_pending);
2414 ASSERT(db->db_level == parent->db_level-1);
2415 ASSERT(arc_released(parent->db_buf));
2416 zio = parent->db_data_pending->dr_zio;
2417 } else {
2418 ASSERT(db->db_level == dn->dn_phys->dn_nlevels-1);
2419 ASSERT3P(db->db_blkptr, ==,
2420 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2421 zio = dn->dn_zio;
2422 }
2423
2424 ASSERT(db->db_level == 0 || data == db->db_buf);
2425 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2426 ASSERT(zio);
2427
2428 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2429 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2430 db->db.db_object, db->db_level, db->db_blkid);
2431
2432 dmu_write_policy(os, dn, db->db_level,
2433 db->db_state == DB_NOFILL ? WP_NOFILL : 0, &zp);
2434
2435 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2436 ASSERT(db->db_state != DB_NOFILL);
2437 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2438 db->db_blkptr, data->b_data, arc_buf_size(data), &zp,
2439 dbuf_write_override_ready, dbuf_write_override_done, dr,
2440 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2441 mutex_enter(&db->db_mtx);
2442 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2443 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2444 dr->dt.dl.dr_copies);
2445 mutex_exit(&db->db_mtx);
2446 } else if (db->db_state == DB_NOFILL) {
2447 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF);
2448 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2449 db->db_blkptr, NULL, db->db.db_size, &zp,
2450 dbuf_write_nofill_ready, dbuf_write_nofill_done, db,
2451 ZIO_PRIORITY_ASYNC_WRITE,
2452 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2453 } else {
2454 ASSERT(arc_released(data));
2455 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2456 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), &zp,
2457 dbuf_write_ready, dbuf_write_done, db,
2458 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2459 }
2460 }
2461