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5047 don't use atomic_*_nv if you discard the return value
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--- old/usr/src/uts/common/fs/zfs/dbuf.c
+++ new/usr/src/uts/common/fs/zfs/dbuf.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21 /*
22 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 24 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
25 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26 26 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
27 27 */
28 28
29 29 #include <sys/zfs_context.h>
30 30 #include <sys/dmu.h>
31 31 #include <sys/dmu_send.h>
32 32 #include <sys/dmu_impl.h>
33 33 #include <sys/dbuf.h>
34 34 #include <sys/dmu_objset.h>
35 35 #include <sys/dsl_dataset.h>
36 36 #include <sys/dsl_dir.h>
37 37 #include <sys/dmu_tx.h>
38 38 #include <sys/spa.h>
39 39 #include <sys/zio.h>
40 40 #include <sys/dmu_zfetch.h>
41 41 #include <sys/sa.h>
42 42 #include <sys/sa_impl.h>
43 43 #include <sys/zfeature.h>
44 44 #include <sys/blkptr.h>
45 45 #include <sys/range_tree.h>
46 46
47 47 /*
48 48 * Number of times that zfs_free_range() took the slow path while doing
49 49 * a zfs receive. A nonzero value indicates a potential performance problem.
50 50 */
51 51 uint64_t zfs_free_range_recv_miss;
52 52
53 53 static void dbuf_destroy(dmu_buf_impl_t *db);
54 54 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
55 55 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
56 56
57 57 /*
58 58 * Global data structures and functions for the dbuf cache.
59 59 */
60 60 static kmem_cache_t *dbuf_cache;
61 61
62 62 /* ARGSUSED */
63 63 static int
64 64 dbuf_cons(void *vdb, void *unused, int kmflag)
65 65 {
66 66 dmu_buf_impl_t *db = vdb;
67 67 bzero(db, sizeof (dmu_buf_impl_t));
68 68
69 69 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
70 70 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
71 71 refcount_create(&db->db_holds);
72 72 return (0);
73 73 }
74 74
75 75 /* ARGSUSED */
76 76 static void
77 77 dbuf_dest(void *vdb, void *unused)
78 78 {
79 79 dmu_buf_impl_t *db = vdb;
80 80 mutex_destroy(&db->db_mtx);
81 81 cv_destroy(&db->db_changed);
82 82 refcount_destroy(&db->db_holds);
83 83 }
84 84
85 85 /*
86 86 * dbuf hash table routines
87 87 */
88 88 static dbuf_hash_table_t dbuf_hash_table;
89 89
90 90 static uint64_t dbuf_hash_count;
91 91
92 92 static uint64_t
93 93 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
94 94 {
95 95 uintptr_t osv = (uintptr_t)os;
96 96 uint64_t crc = -1ULL;
97 97
98 98 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
99 99 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
100 100 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
101 101 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
102 102 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
103 103 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
104 104 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
105 105
106 106 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
107 107
108 108 return (crc);
109 109 }
110 110
111 111 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
112 112
113 113 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
114 114 ((dbuf)->db.db_object == (obj) && \
115 115 (dbuf)->db_objset == (os) && \
116 116 (dbuf)->db_level == (level) && \
117 117 (dbuf)->db_blkid == (blkid))
118 118
119 119 dmu_buf_impl_t *
120 120 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
121 121 {
122 122 dbuf_hash_table_t *h = &dbuf_hash_table;
123 123 objset_t *os = dn->dn_objset;
124 124 uint64_t obj = dn->dn_object;
125 125 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
126 126 uint64_t idx = hv & h->hash_table_mask;
127 127 dmu_buf_impl_t *db;
128 128
129 129 mutex_enter(DBUF_HASH_MUTEX(h, idx));
130 130 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
131 131 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
132 132 mutex_enter(&db->db_mtx);
133 133 if (db->db_state != DB_EVICTING) {
134 134 mutex_exit(DBUF_HASH_MUTEX(h, idx));
135 135 return (db);
136 136 }
137 137 mutex_exit(&db->db_mtx);
138 138 }
139 139 }
140 140 mutex_exit(DBUF_HASH_MUTEX(h, idx));
141 141 return (NULL);
142 142 }
143 143
144 144 /*
145 145 * Insert an entry into the hash table. If there is already an element
146 146 * equal to elem in the hash table, then the already existing element
147 147 * will be returned and the new element will not be inserted.
148 148 * Otherwise returns NULL.
149 149 */
150 150 static dmu_buf_impl_t *
151 151 dbuf_hash_insert(dmu_buf_impl_t *db)
152 152 {
153 153 dbuf_hash_table_t *h = &dbuf_hash_table;
154 154 objset_t *os = db->db_objset;
155 155 uint64_t obj = db->db.db_object;
156 156 int level = db->db_level;
157 157 uint64_t blkid = db->db_blkid;
158 158 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
159 159 uint64_t idx = hv & h->hash_table_mask;
160 160 dmu_buf_impl_t *dbf;
161 161
162 162 mutex_enter(DBUF_HASH_MUTEX(h, idx));
163 163 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
164 164 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
165 165 mutex_enter(&dbf->db_mtx);
166 166 if (dbf->db_state != DB_EVICTING) {
167 167 mutex_exit(DBUF_HASH_MUTEX(h, idx));
168 168 return (dbf);
169 169 }
170 170 mutex_exit(&dbf->db_mtx);
171 171 }
172 172 }
173 173
174 174 mutex_enter(&db->db_mtx);
175 175 db->db_hash_next = h->hash_table[idx];
176 176 h->hash_table[idx] = db;
177 177 mutex_exit(DBUF_HASH_MUTEX(h, idx));
178 178 atomic_inc_64(&dbuf_hash_count);
179 179
180 180 return (NULL);
181 181 }
182 182
183 183 /*
184 184 * Remove an entry from the hash table. This operation will
185 185 * fail if there are any existing holds on the db.
186 186 */
187 187 static void
188 188 dbuf_hash_remove(dmu_buf_impl_t *db)
189 189 {
190 190 dbuf_hash_table_t *h = &dbuf_hash_table;
191 191 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
192 192 db->db_level, db->db_blkid);
193 193 uint64_t idx = hv & h->hash_table_mask;
194 194 dmu_buf_impl_t *dbf, **dbp;
195 195
196 196 /*
197 197 * We musn't hold db_mtx to maintin lock ordering:
198 198 * DBUF_HASH_MUTEX > db_mtx.
199 199 */
200 200 ASSERT(refcount_is_zero(&db->db_holds));
201 201 ASSERT(db->db_state == DB_EVICTING);
202 202 ASSERT(!MUTEX_HELD(&db->db_mtx));
203 203
204 204 mutex_enter(DBUF_HASH_MUTEX(h, idx));
205 205 dbp = &h->hash_table[idx];
206 206 while ((dbf = *dbp) != db) {
207 207 dbp = &dbf->db_hash_next;
208 208 ASSERT(dbf != NULL);
209 209 }
210 210 *dbp = db->db_hash_next;
211 211 db->db_hash_next = NULL;
212 212 mutex_exit(DBUF_HASH_MUTEX(h, idx));
213 213 atomic_dec_64(&dbuf_hash_count);
214 214 }
215 215
216 216 static arc_evict_func_t dbuf_do_evict;
217 217
218 218 static void
219 219 dbuf_evict_user(dmu_buf_impl_t *db)
220 220 {
221 221 ASSERT(MUTEX_HELD(&db->db_mtx));
222 222
223 223 if (db->db_level != 0 || db->db_evict_func == NULL)
224 224 return;
225 225
226 226 if (db->db_user_data_ptr_ptr)
227 227 *db->db_user_data_ptr_ptr = db->db.db_data;
228 228 db->db_evict_func(&db->db, db->db_user_ptr);
229 229 db->db_user_ptr = NULL;
230 230 db->db_user_data_ptr_ptr = NULL;
231 231 db->db_evict_func = NULL;
232 232 }
233 233
234 234 boolean_t
235 235 dbuf_is_metadata(dmu_buf_impl_t *db)
236 236 {
237 237 if (db->db_level > 0) {
238 238 return (B_TRUE);
239 239 } else {
240 240 boolean_t is_metadata;
241 241
242 242 DB_DNODE_ENTER(db);
243 243 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
244 244 DB_DNODE_EXIT(db);
245 245
246 246 return (is_metadata);
247 247 }
248 248 }
249 249
250 250 void
251 251 dbuf_evict(dmu_buf_impl_t *db)
252 252 {
253 253 ASSERT(MUTEX_HELD(&db->db_mtx));
254 254 ASSERT(db->db_buf == NULL);
255 255 ASSERT(db->db_data_pending == NULL);
256 256
257 257 dbuf_clear(db);
258 258 dbuf_destroy(db);
259 259 }
260 260
261 261 void
262 262 dbuf_init(void)
263 263 {
264 264 uint64_t hsize = 1ULL << 16;
265 265 dbuf_hash_table_t *h = &dbuf_hash_table;
266 266 int i;
267 267
268 268 /*
269 269 * The hash table is big enough to fill all of physical memory
270 270 * with an average 4K block size. The table will take up
271 271 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
272 272 */
273 273 while (hsize * 4096 < physmem * PAGESIZE)
274 274 hsize <<= 1;
275 275
276 276 retry:
277 277 h->hash_table_mask = hsize - 1;
278 278 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
279 279 if (h->hash_table == NULL) {
280 280 /* XXX - we should really return an error instead of assert */
281 281 ASSERT(hsize > (1ULL << 10));
282 282 hsize >>= 1;
283 283 goto retry;
284 284 }
285 285
286 286 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
287 287 sizeof (dmu_buf_impl_t),
288 288 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
289 289
290 290 for (i = 0; i < DBUF_MUTEXES; i++)
291 291 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
292 292 }
293 293
294 294 void
295 295 dbuf_fini(void)
296 296 {
297 297 dbuf_hash_table_t *h = &dbuf_hash_table;
298 298 int i;
299 299
300 300 for (i = 0; i < DBUF_MUTEXES; i++)
301 301 mutex_destroy(&h->hash_mutexes[i]);
302 302 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
303 303 kmem_cache_destroy(dbuf_cache);
304 304 }
305 305
306 306 /*
307 307 * Other stuff.
308 308 */
309 309
310 310 #ifdef ZFS_DEBUG
311 311 static void
312 312 dbuf_verify(dmu_buf_impl_t *db)
313 313 {
314 314 dnode_t *dn;
315 315 dbuf_dirty_record_t *dr;
316 316
317 317 ASSERT(MUTEX_HELD(&db->db_mtx));
318 318
319 319 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
320 320 return;
321 321
322 322 ASSERT(db->db_objset != NULL);
323 323 DB_DNODE_ENTER(db);
324 324 dn = DB_DNODE(db);
325 325 if (dn == NULL) {
326 326 ASSERT(db->db_parent == NULL);
327 327 ASSERT(db->db_blkptr == NULL);
328 328 } else {
329 329 ASSERT3U(db->db.db_object, ==, dn->dn_object);
330 330 ASSERT3P(db->db_objset, ==, dn->dn_objset);
331 331 ASSERT3U(db->db_level, <, dn->dn_nlevels);
332 332 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
333 333 db->db_blkid == DMU_SPILL_BLKID ||
334 334 !list_is_empty(&dn->dn_dbufs));
335 335 }
336 336 if (db->db_blkid == DMU_BONUS_BLKID) {
337 337 ASSERT(dn != NULL);
338 338 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
339 339 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
340 340 } else if (db->db_blkid == DMU_SPILL_BLKID) {
341 341 ASSERT(dn != NULL);
342 342 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
343 343 ASSERT0(db->db.db_offset);
344 344 } else {
345 345 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
346 346 }
347 347
348 348 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
349 349 ASSERT(dr->dr_dbuf == db);
350 350
351 351 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
352 352 ASSERT(dr->dr_dbuf == db);
353 353
354 354 /*
355 355 * We can't assert that db_size matches dn_datablksz because it
356 356 * can be momentarily different when another thread is doing
357 357 * dnode_set_blksz().
358 358 */
359 359 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
360 360 dr = db->db_data_pending;
361 361 /*
362 362 * It should only be modified in syncing context, so
363 363 * make sure we only have one copy of the data.
364 364 */
365 365 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
366 366 }
367 367
368 368 /* verify db->db_blkptr */
369 369 if (db->db_blkptr) {
370 370 if (db->db_parent == dn->dn_dbuf) {
371 371 /* db is pointed to by the dnode */
372 372 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
373 373 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
374 374 ASSERT(db->db_parent == NULL);
375 375 else
376 376 ASSERT(db->db_parent != NULL);
377 377 if (db->db_blkid != DMU_SPILL_BLKID)
378 378 ASSERT3P(db->db_blkptr, ==,
379 379 &dn->dn_phys->dn_blkptr[db->db_blkid]);
380 380 } else {
381 381 /* db is pointed to by an indirect block */
382 382 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
383 383 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
384 384 ASSERT3U(db->db_parent->db.db_object, ==,
385 385 db->db.db_object);
386 386 /*
387 387 * dnode_grow_indblksz() can make this fail if we don't
388 388 * have the struct_rwlock. XXX indblksz no longer
389 389 * grows. safe to do this now?
390 390 */
391 391 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
392 392 ASSERT3P(db->db_blkptr, ==,
393 393 ((blkptr_t *)db->db_parent->db.db_data +
394 394 db->db_blkid % epb));
395 395 }
396 396 }
397 397 }
398 398 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
399 399 (db->db_buf == NULL || db->db_buf->b_data) &&
400 400 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
401 401 db->db_state != DB_FILL && !dn->dn_free_txg) {
402 402 /*
403 403 * If the blkptr isn't set but they have nonzero data,
404 404 * it had better be dirty, otherwise we'll lose that
405 405 * data when we evict this buffer.
406 406 */
407 407 if (db->db_dirtycnt == 0) {
408 408 uint64_t *buf = db->db.db_data;
409 409 int i;
410 410
411 411 for (i = 0; i < db->db.db_size >> 3; i++) {
412 412 ASSERT(buf[i] == 0);
413 413 }
414 414 }
415 415 }
416 416 DB_DNODE_EXIT(db);
417 417 }
418 418 #endif
419 419
420 420 static void
421 421 dbuf_update_data(dmu_buf_impl_t *db)
422 422 {
423 423 ASSERT(MUTEX_HELD(&db->db_mtx));
424 424 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
425 425 ASSERT(!refcount_is_zero(&db->db_holds));
426 426 *db->db_user_data_ptr_ptr = db->db.db_data;
427 427 }
428 428 }
429 429
430 430 static void
431 431 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
432 432 {
433 433 ASSERT(MUTEX_HELD(&db->db_mtx));
434 434 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
435 435 db->db_buf = buf;
436 436 if (buf != NULL) {
437 437 ASSERT(buf->b_data != NULL);
438 438 db->db.db_data = buf->b_data;
439 439 if (!arc_released(buf))
440 440 arc_set_callback(buf, dbuf_do_evict, db);
441 441 dbuf_update_data(db);
442 442 } else {
443 443 dbuf_evict_user(db);
444 444 db->db.db_data = NULL;
445 445 if (db->db_state != DB_NOFILL)
446 446 db->db_state = DB_UNCACHED;
447 447 }
448 448 }
449 449
450 450 /*
451 451 * Loan out an arc_buf for read. Return the loaned arc_buf.
452 452 */
453 453 arc_buf_t *
454 454 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
455 455 {
456 456 arc_buf_t *abuf;
457 457
458 458 mutex_enter(&db->db_mtx);
459 459 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
460 460 int blksz = db->db.db_size;
461 461 spa_t *spa = db->db_objset->os_spa;
462 462
463 463 mutex_exit(&db->db_mtx);
464 464 abuf = arc_loan_buf(spa, blksz);
465 465 bcopy(db->db.db_data, abuf->b_data, blksz);
466 466 } else {
467 467 abuf = db->db_buf;
468 468 arc_loan_inuse_buf(abuf, db);
469 469 dbuf_set_data(db, NULL);
470 470 mutex_exit(&db->db_mtx);
471 471 }
472 472 return (abuf);
473 473 }
474 474
475 475 uint64_t
476 476 dbuf_whichblock(dnode_t *dn, uint64_t offset)
477 477 {
478 478 if (dn->dn_datablkshift) {
479 479 return (offset >> dn->dn_datablkshift);
480 480 } else {
481 481 ASSERT3U(offset, <, dn->dn_datablksz);
482 482 return (0);
483 483 }
484 484 }
485 485
486 486 static void
487 487 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
488 488 {
489 489 dmu_buf_impl_t *db = vdb;
490 490
491 491 mutex_enter(&db->db_mtx);
492 492 ASSERT3U(db->db_state, ==, DB_READ);
493 493 /*
494 494 * All reads are synchronous, so we must have a hold on the dbuf
495 495 */
496 496 ASSERT(refcount_count(&db->db_holds) > 0);
497 497 ASSERT(db->db_buf == NULL);
498 498 ASSERT(db->db.db_data == NULL);
499 499 if (db->db_level == 0 && db->db_freed_in_flight) {
500 500 /* we were freed in flight; disregard any error */
501 501 arc_release(buf, db);
502 502 bzero(buf->b_data, db->db.db_size);
503 503 arc_buf_freeze(buf);
504 504 db->db_freed_in_flight = FALSE;
505 505 dbuf_set_data(db, buf);
506 506 db->db_state = DB_CACHED;
507 507 } else if (zio == NULL || zio->io_error == 0) {
508 508 dbuf_set_data(db, buf);
509 509 db->db_state = DB_CACHED;
510 510 } else {
511 511 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
512 512 ASSERT3P(db->db_buf, ==, NULL);
513 513 VERIFY(arc_buf_remove_ref(buf, db));
514 514 db->db_state = DB_UNCACHED;
515 515 }
516 516 cv_broadcast(&db->db_changed);
517 517 dbuf_rele_and_unlock(db, NULL);
518 518 }
519 519
520 520 static void
521 521 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
522 522 {
523 523 dnode_t *dn;
524 524 zbookmark_phys_t zb;
525 525 uint32_t aflags = ARC_NOWAIT;
526 526
527 527 DB_DNODE_ENTER(db);
528 528 dn = DB_DNODE(db);
529 529 ASSERT(!refcount_is_zero(&db->db_holds));
530 530 /* We need the struct_rwlock to prevent db_blkptr from changing. */
531 531 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
532 532 ASSERT(MUTEX_HELD(&db->db_mtx));
533 533 ASSERT(db->db_state == DB_UNCACHED);
534 534 ASSERT(db->db_buf == NULL);
535 535
536 536 if (db->db_blkid == DMU_BONUS_BLKID) {
537 537 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
538 538
539 539 ASSERT3U(bonuslen, <=, db->db.db_size);
540 540 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
541 541 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
542 542 if (bonuslen < DN_MAX_BONUSLEN)
543 543 bzero(db->db.db_data, DN_MAX_BONUSLEN);
544 544 if (bonuslen)
545 545 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
546 546 DB_DNODE_EXIT(db);
547 547 dbuf_update_data(db);
548 548 db->db_state = DB_CACHED;
549 549 mutex_exit(&db->db_mtx);
550 550 return;
551 551 }
552 552
553 553 /*
554 554 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
555 555 * processes the delete record and clears the bp while we are waiting
556 556 * for the dn_mtx (resulting in a "no" from block_freed).
557 557 */
558 558 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
559 559 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
560 560 BP_IS_HOLE(db->db_blkptr)))) {
561 561 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
562 562
563 563 DB_DNODE_EXIT(db);
564 564 dbuf_set_data(db, arc_buf_alloc(db->db_objset->os_spa,
565 565 db->db.db_size, db, type));
566 566 bzero(db->db.db_data, db->db.db_size);
567 567 db->db_state = DB_CACHED;
568 568 *flags |= DB_RF_CACHED;
569 569 mutex_exit(&db->db_mtx);
570 570 return;
571 571 }
572 572
573 573 DB_DNODE_EXIT(db);
574 574
575 575 db->db_state = DB_READ;
576 576 mutex_exit(&db->db_mtx);
577 577
578 578 if (DBUF_IS_L2CACHEABLE(db))
579 579 aflags |= ARC_L2CACHE;
580 580 if (DBUF_IS_L2COMPRESSIBLE(db))
581 581 aflags |= ARC_L2COMPRESS;
582 582
583 583 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
584 584 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
585 585 db->db.db_object, db->db_level, db->db_blkid);
586 586
587 587 dbuf_add_ref(db, NULL);
588 588
589 589 (void) arc_read(zio, db->db_objset->os_spa, db->db_blkptr,
590 590 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
591 591 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
592 592 &aflags, &zb);
593 593 if (aflags & ARC_CACHED)
594 594 *flags |= DB_RF_CACHED;
595 595 }
596 596
597 597 int
598 598 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
599 599 {
600 600 int err = 0;
601 601 boolean_t havepzio = (zio != NULL);
602 602 boolean_t prefetch;
603 603 dnode_t *dn;
604 604
605 605 /*
606 606 * We don't have to hold the mutex to check db_state because it
607 607 * can't be freed while we have a hold on the buffer.
608 608 */
609 609 ASSERT(!refcount_is_zero(&db->db_holds));
610 610
611 611 if (db->db_state == DB_NOFILL)
612 612 return (SET_ERROR(EIO));
613 613
614 614 DB_DNODE_ENTER(db);
615 615 dn = DB_DNODE(db);
616 616 if ((flags & DB_RF_HAVESTRUCT) == 0)
617 617 rw_enter(&dn->dn_struct_rwlock, RW_READER);
618 618
619 619 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
620 620 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
621 621 DBUF_IS_CACHEABLE(db);
622 622
623 623 mutex_enter(&db->db_mtx);
624 624 if (db->db_state == DB_CACHED) {
625 625 mutex_exit(&db->db_mtx);
626 626 if (prefetch)
627 627 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
628 628 db->db.db_size, TRUE);
629 629 if ((flags & DB_RF_HAVESTRUCT) == 0)
630 630 rw_exit(&dn->dn_struct_rwlock);
631 631 DB_DNODE_EXIT(db);
632 632 } else if (db->db_state == DB_UNCACHED) {
633 633 spa_t *spa = dn->dn_objset->os_spa;
634 634
635 635 if (zio == NULL)
636 636 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
637 637 dbuf_read_impl(db, zio, &flags);
638 638
639 639 /* dbuf_read_impl has dropped db_mtx for us */
640 640
641 641 if (prefetch)
642 642 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
643 643 db->db.db_size, flags & DB_RF_CACHED);
644 644
645 645 if ((flags & DB_RF_HAVESTRUCT) == 0)
646 646 rw_exit(&dn->dn_struct_rwlock);
647 647 DB_DNODE_EXIT(db);
648 648
649 649 if (!havepzio)
650 650 err = zio_wait(zio);
651 651 } else {
652 652 /*
653 653 * Another reader came in while the dbuf was in flight
654 654 * between UNCACHED and CACHED. Either a writer will finish
655 655 * writing the buffer (sending the dbuf to CACHED) or the
656 656 * first reader's request will reach the read_done callback
657 657 * and send the dbuf to CACHED. Otherwise, a failure
658 658 * occurred and the dbuf went to UNCACHED.
659 659 */
660 660 mutex_exit(&db->db_mtx);
661 661 if (prefetch)
662 662 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
663 663 db->db.db_size, TRUE);
664 664 if ((flags & DB_RF_HAVESTRUCT) == 0)
665 665 rw_exit(&dn->dn_struct_rwlock);
666 666 DB_DNODE_EXIT(db);
667 667
668 668 /* Skip the wait per the caller's request. */
669 669 mutex_enter(&db->db_mtx);
670 670 if ((flags & DB_RF_NEVERWAIT) == 0) {
671 671 while (db->db_state == DB_READ ||
672 672 db->db_state == DB_FILL) {
673 673 ASSERT(db->db_state == DB_READ ||
674 674 (flags & DB_RF_HAVESTRUCT) == 0);
675 675 cv_wait(&db->db_changed, &db->db_mtx);
676 676 }
677 677 if (db->db_state == DB_UNCACHED)
678 678 err = SET_ERROR(EIO);
679 679 }
680 680 mutex_exit(&db->db_mtx);
681 681 }
682 682
683 683 ASSERT(err || havepzio || db->db_state == DB_CACHED);
684 684 return (err);
685 685 }
686 686
687 687 static void
688 688 dbuf_noread(dmu_buf_impl_t *db)
689 689 {
690 690 ASSERT(!refcount_is_zero(&db->db_holds));
691 691 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
692 692 mutex_enter(&db->db_mtx);
693 693 while (db->db_state == DB_READ || db->db_state == DB_FILL)
694 694 cv_wait(&db->db_changed, &db->db_mtx);
695 695 if (db->db_state == DB_UNCACHED) {
696 696 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
697 697 spa_t *spa = db->db_objset->os_spa;
698 698
699 699 ASSERT(db->db_buf == NULL);
700 700 ASSERT(db->db.db_data == NULL);
701 701 dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
702 702 db->db_state = DB_FILL;
703 703 } else if (db->db_state == DB_NOFILL) {
704 704 dbuf_set_data(db, NULL);
705 705 } else {
706 706 ASSERT3U(db->db_state, ==, DB_CACHED);
707 707 }
708 708 mutex_exit(&db->db_mtx);
709 709 }
710 710
711 711 /*
712 712 * This is our just-in-time copy function. It makes a copy of
713 713 * buffers, that have been modified in a previous transaction
714 714 * group, before we modify them in the current active group.
715 715 *
716 716 * This function is used in two places: when we are dirtying a
717 717 * buffer for the first time in a txg, and when we are freeing
718 718 * a range in a dnode that includes this buffer.
719 719 *
720 720 * Note that when we are called from dbuf_free_range() we do
721 721 * not put a hold on the buffer, we just traverse the active
722 722 * dbuf list for the dnode.
723 723 */
724 724 static void
725 725 dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg)
726 726 {
727 727 dbuf_dirty_record_t *dr = db->db_last_dirty;
728 728
729 729 ASSERT(MUTEX_HELD(&db->db_mtx));
730 730 ASSERT(db->db.db_data != NULL);
731 731 ASSERT(db->db_level == 0);
732 732 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT);
733 733
734 734 if (dr == NULL ||
735 735 (dr->dt.dl.dr_data !=
736 736 ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf)))
737 737 return;
738 738
739 739 /*
740 740 * If the last dirty record for this dbuf has not yet synced
741 741 * and its referencing the dbuf data, either:
742 742 * reset the reference to point to a new copy,
743 743 * or (if there a no active holders)
744 744 * just null out the current db_data pointer.
745 745 */
746 746 ASSERT(dr->dr_txg >= txg - 2);
747 747 if (db->db_blkid == DMU_BONUS_BLKID) {
748 748 /* Note that the data bufs here are zio_bufs */
749 749 dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
750 750 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
751 751 bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
752 752 } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
753 753 int size = db->db.db_size;
754 754 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
755 755 spa_t *spa = db->db_objset->os_spa;
756 756
757 757 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
758 758 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
759 759 } else {
760 760 dbuf_set_data(db, NULL);
761 761 }
762 762 }
763 763
764 764 void
765 765 dbuf_unoverride(dbuf_dirty_record_t *dr)
766 766 {
767 767 dmu_buf_impl_t *db = dr->dr_dbuf;
768 768 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
769 769 uint64_t txg = dr->dr_txg;
770 770
771 771 ASSERT(MUTEX_HELD(&db->db_mtx));
772 772 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
773 773 ASSERT(db->db_level == 0);
774 774
775 775 if (db->db_blkid == DMU_BONUS_BLKID ||
776 776 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
777 777 return;
778 778
779 779 ASSERT(db->db_data_pending != dr);
780 780
781 781 /* free this block */
782 782 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite)
783 783 zio_free(db->db_objset->os_spa, txg, bp);
784 784
785 785 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
786 786 dr->dt.dl.dr_nopwrite = B_FALSE;
787 787
788 788 /*
789 789 * Release the already-written buffer, so we leave it in
790 790 * a consistent dirty state. Note that all callers are
791 791 * modifying the buffer, so they will immediately do
792 792 * another (redundant) arc_release(). Therefore, leave
793 793 * the buf thawed to save the effort of freezing &
794 794 * immediately re-thawing it.
795 795 */
796 796 arc_release(dr->dt.dl.dr_data, db);
797 797 }
798 798
799 799 /*
800 800 * Evict (if its unreferenced) or clear (if its referenced) any level-0
801 801 * data blocks in the free range, so that any future readers will find
802 802 * empty blocks.
803 803 *
804 804 * This is a no-op if the dataset is in the middle of an incremental
805 805 * receive; see comment below for details.
806 806 */
807 807 void
808 808 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
809 809 {
810 810 dmu_buf_impl_t *db, *db_next;
811 811 uint64_t txg = tx->tx_txg;
812 812
813 813 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID))
814 814 end = dn->dn_maxblkid;
815 815 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
816 816
817 817 mutex_enter(&dn->dn_dbufs_mtx);
818 818 if (start >= dn->dn_unlisted_l0_blkid * dn->dn_datablksz) {
819 819 /* There can't be any dbufs in this range; no need to search. */
820 820 mutex_exit(&dn->dn_dbufs_mtx);
821 821 return;
822 822 } else if (dmu_objset_is_receiving(dn->dn_objset)) {
823 823 /*
824 824 * If we are receiving, we expect there to be no dbufs in
825 825 * the range to be freed, because receive modifies each
826 826 * block at most once, and in offset order. If this is
827 827 * not the case, it can lead to performance problems,
828 828 * so note that we unexpectedly took the slow path.
829 829 */
830 830 atomic_inc_64(&zfs_free_range_recv_miss);
831 831 }
832 832
833 833 for (db = list_head(&dn->dn_dbufs); db != NULL; db = db_next) {
834 834 db_next = list_next(&dn->dn_dbufs, db);
835 835 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
836 836
837 837 if (db->db_level != 0)
838 838 continue;
839 839 if (db->db_blkid < start || db->db_blkid > end)
840 840 continue;
841 841
842 842 /* found a level 0 buffer in the range */
843 843 mutex_enter(&db->db_mtx);
844 844 if (dbuf_undirty(db, tx)) {
845 845 /* mutex has been dropped and dbuf destroyed */
846 846 continue;
847 847 }
848 848
849 849 if (db->db_state == DB_UNCACHED ||
850 850 db->db_state == DB_NOFILL ||
851 851 db->db_state == DB_EVICTING) {
852 852 ASSERT(db->db.db_data == NULL);
853 853 mutex_exit(&db->db_mtx);
854 854 continue;
855 855 }
856 856 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
857 857 /* will be handled in dbuf_read_done or dbuf_rele */
858 858 db->db_freed_in_flight = TRUE;
859 859 mutex_exit(&db->db_mtx);
860 860 continue;
861 861 }
862 862 if (refcount_count(&db->db_holds) == 0) {
863 863 ASSERT(db->db_buf);
864 864 dbuf_clear(db);
865 865 continue;
866 866 }
867 867 /* The dbuf is referenced */
868 868
869 869 if (db->db_last_dirty != NULL) {
870 870 dbuf_dirty_record_t *dr = db->db_last_dirty;
871 871
872 872 if (dr->dr_txg == txg) {
873 873 /*
874 874 * This buffer is "in-use", re-adjust the file
875 875 * size to reflect that this buffer may
876 876 * contain new data when we sync.
877 877 */
878 878 if (db->db_blkid != DMU_SPILL_BLKID &&
879 879 db->db_blkid > dn->dn_maxblkid)
880 880 dn->dn_maxblkid = db->db_blkid;
881 881 dbuf_unoverride(dr);
882 882 } else {
883 883 /*
884 884 * This dbuf is not dirty in the open context.
885 885 * Either uncache it (if its not referenced in
886 886 * the open context) or reset its contents to
887 887 * empty.
888 888 */
889 889 dbuf_fix_old_data(db, txg);
890 890 }
891 891 }
892 892 /* clear the contents if its cached */
893 893 if (db->db_state == DB_CACHED) {
894 894 ASSERT(db->db.db_data != NULL);
895 895 arc_release(db->db_buf, db);
896 896 bzero(db->db.db_data, db->db.db_size);
897 897 arc_buf_freeze(db->db_buf);
898 898 }
899 899
900 900 mutex_exit(&db->db_mtx);
901 901 }
902 902 mutex_exit(&dn->dn_dbufs_mtx);
903 903 }
904 904
905 905 static int
906 906 dbuf_block_freeable(dmu_buf_impl_t *db)
907 907 {
908 908 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
909 909 uint64_t birth_txg = 0;
910 910
911 911 /*
912 912 * We don't need any locking to protect db_blkptr:
913 913 * If it's syncing, then db_last_dirty will be set
914 914 * so we'll ignore db_blkptr.
915 915 *
916 916 * This logic ensures that only block births for
917 917 * filled blocks are considered.
918 918 */
919 919 ASSERT(MUTEX_HELD(&db->db_mtx));
920 920 if (db->db_last_dirty && (db->db_blkptr == NULL ||
921 921 !BP_IS_HOLE(db->db_blkptr))) {
922 922 birth_txg = db->db_last_dirty->dr_txg;
923 923 } else if (db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) {
924 924 birth_txg = db->db_blkptr->blk_birth;
925 925 }
926 926
927 927 /*
928 928 * If this block don't exist or is in a snapshot, it can't be freed.
929 929 * Don't pass the bp to dsl_dataset_block_freeable() since we
930 930 * are holding the db_mtx lock and might deadlock if we are
931 931 * prefetching a dedup-ed block.
932 932 */
933 933 if (birth_txg != 0)
934 934 return (ds == NULL ||
935 935 dsl_dataset_block_freeable(ds, NULL, birth_txg));
936 936 else
937 937 return (B_FALSE);
938 938 }
939 939
940 940 void
941 941 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
942 942 {
943 943 arc_buf_t *buf, *obuf;
944 944 int osize = db->db.db_size;
945 945 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
946 946 dnode_t *dn;
947 947
948 948 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
949 949
950 950 DB_DNODE_ENTER(db);
951 951 dn = DB_DNODE(db);
952 952
953 953 /* XXX does *this* func really need the lock? */
954 954 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
955 955
956 956 /*
957 957 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held
958 958 * is OK, because there can be no other references to the db
959 959 * when we are changing its size, so no concurrent DB_FILL can
960 960 * be happening.
961 961 */
962 962 /*
963 963 * XXX we should be doing a dbuf_read, checking the return
964 964 * value and returning that up to our callers
965 965 */
966 966 dmu_buf_will_dirty(&db->db, tx);
967 967
968 968 /* create the data buffer for the new block */
969 969 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
970 970
971 971 /* copy old block data to the new block */
972 972 obuf = db->db_buf;
973 973 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
974 974 /* zero the remainder */
975 975 if (size > osize)
976 976 bzero((uint8_t *)buf->b_data + osize, size - osize);
977 977
978 978 mutex_enter(&db->db_mtx);
979 979 dbuf_set_data(db, buf);
980 980 VERIFY(arc_buf_remove_ref(obuf, db));
981 981 db->db.db_size = size;
982 982
983 983 if (db->db_level == 0) {
984 984 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
985 985 db->db_last_dirty->dt.dl.dr_data = buf;
986 986 }
987 987 mutex_exit(&db->db_mtx);
988 988
989 989 dnode_willuse_space(dn, size-osize, tx);
990 990 DB_DNODE_EXIT(db);
991 991 }
992 992
993 993 void
994 994 dbuf_release_bp(dmu_buf_impl_t *db)
995 995 {
996 996 objset_t *os = db->db_objset;
997 997
998 998 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
999 999 ASSERT(arc_released(os->os_phys_buf) ||
1000 1000 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1001 1001 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1002 1002
1003 1003 (void) arc_release(db->db_buf, db);
1004 1004 }
1005 1005
1006 1006 dbuf_dirty_record_t *
1007 1007 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1008 1008 {
1009 1009 dnode_t *dn;
1010 1010 objset_t *os;
1011 1011 dbuf_dirty_record_t **drp, *dr;
1012 1012 int drop_struct_lock = FALSE;
1013 1013 boolean_t do_free_accounting = B_FALSE;
1014 1014 int txgoff = tx->tx_txg & TXG_MASK;
1015 1015
1016 1016 ASSERT(tx->tx_txg != 0);
1017 1017 ASSERT(!refcount_is_zero(&db->db_holds));
1018 1018 DMU_TX_DIRTY_BUF(tx, db);
1019 1019
1020 1020 DB_DNODE_ENTER(db);
1021 1021 dn = DB_DNODE(db);
1022 1022 /*
1023 1023 * Shouldn't dirty a regular buffer in syncing context. Private
1024 1024 * objects may be dirtied in syncing context, but only if they
1025 1025 * were already pre-dirtied in open context.
1026 1026 */
1027 1027 ASSERT(!dmu_tx_is_syncing(tx) ||
1028 1028 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1029 1029 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1030 1030 dn->dn_objset->os_dsl_dataset == NULL);
1031 1031 /*
1032 1032 * We make this assert for private objects as well, but after we
1033 1033 * check if we're already dirty. They are allowed to re-dirty
1034 1034 * in syncing context.
1035 1035 */
1036 1036 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1037 1037 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1038 1038 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1039 1039
1040 1040 mutex_enter(&db->db_mtx);
1041 1041 /*
1042 1042 * XXX make this true for indirects too? The problem is that
1043 1043 * transactions created with dmu_tx_create_assigned() from
1044 1044 * syncing context don't bother holding ahead.
1045 1045 */
1046 1046 ASSERT(db->db_level != 0 ||
1047 1047 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1048 1048 db->db_state == DB_NOFILL);
1049 1049
1050 1050 mutex_enter(&dn->dn_mtx);
1051 1051 /*
1052 1052 * Don't set dirtyctx to SYNC if we're just modifying this as we
1053 1053 * initialize the objset.
1054 1054 */
1055 1055 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1056 1056 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1057 1057 dn->dn_dirtyctx =
1058 1058 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1059 1059 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1060 1060 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1061 1061 }
1062 1062 mutex_exit(&dn->dn_mtx);
1063 1063
1064 1064 if (db->db_blkid == DMU_SPILL_BLKID)
1065 1065 dn->dn_have_spill = B_TRUE;
1066 1066
1067 1067 /*
1068 1068 * If this buffer is already dirty, we're done.
1069 1069 */
1070 1070 drp = &db->db_last_dirty;
1071 1071 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1072 1072 db->db.db_object == DMU_META_DNODE_OBJECT);
1073 1073 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1074 1074 drp = &dr->dr_next;
1075 1075 if (dr && dr->dr_txg == tx->tx_txg) {
1076 1076 DB_DNODE_EXIT(db);
1077 1077
1078 1078 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1079 1079 /*
1080 1080 * If this buffer has already been written out,
1081 1081 * we now need to reset its state.
1082 1082 */
1083 1083 dbuf_unoverride(dr);
1084 1084 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1085 1085 db->db_state != DB_NOFILL)
1086 1086 arc_buf_thaw(db->db_buf);
1087 1087 }
1088 1088 mutex_exit(&db->db_mtx);
1089 1089 return (dr);
1090 1090 }
1091 1091
1092 1092 /*
1093 1093 * Only valid if not already dirty.
1094 1094 */
1095 1095 ASSERT(dn->dn_object == 0 ||
1096 1096 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1097 1097 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1098 1098
1099 1099 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1100 1100 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1101 1101 dn->dn_phys->dn_nlevels > db->db_level ||
1102 1102 dn->dn_next_nlevels[txgoff] > db->db_level ||
1103 1103 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1104 1104 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1105 1105
1106 1106 /*
1107 1107 * We should only be dirtying in syncing context if it's the
1108 1108 * mos or we're initializing the os or it's a special object.
1109 1109 * However, we are allowed to dirty in syncing context provided
1110 1110 * we already dirtied it in open context. Hence we must make
1111 1111 * this assertion only if we're not already dirty.
1112 1112 */
1113 1113 os = dn->dn_objset;
1114 1114 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1115 1115 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1116 1116 ASSERT(db->db.db_size != 0);
1117 1117
1118 1118 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1119 1119
1120 1120 if (db->db_blkid != DMU_BONUS_BLKID) {
1121 1121 /*
1122 1122 * Update the accounting.
1123 1123 * Note: we delay "free accounting" until after we drop
1124 1124 * the db_mtx. This keeps us from grabbing other locks
1125 1125 * (and possibly deadlocking) in bp_get_dsize() while
1126 1126 * also holding the db_mtx.
1127 1127 */
1128 1128 dnode_willuse_space(dn, db->db.db_size, tx);
1129 1129 do_free_accounting = dbuf_block_freeable(db);
1130 1130 }
1131 1131
1132 1132 /*
1133 1133 * If this buffer is dirty in an old transaction group we need
1134 1134 * to make a copy of it so that the changes we make in this
1135 1135 * transaction group won't leak out when we sync the older txg.
1136 1136 */
1137 1137 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1138 1138 if (db->db_level == 0) {
1139 1139 void *data_old = db->db_buf;
1140 1140
1141 1141 if (db->db_state != DB_NOFILL) {
1142 1142 if (db->db_blkid == DMU_BONUS_BLKID) {
1143 1143 dbuf_fix_old_data(db, tx->tx_txg);
1144 1144 data_old = db->db.db_data;
1145 1145 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1146 1146 /*
1147 1147 * Release the data buffer from the cache so
1148 1148 * that we can modify it without impacting
1149 1149 * possible other users of this cached data
1150 1150 * block. Note that indirect blocks and
1151 1151 * private objects are not released until the
1152 1152 * syncing state (since they are only modified
1153 1153 * then).
1154 1154 */
1155 1155 arc_release(db->db_buf, db);
1156 1156 dbuf_fix_old_data(db, tx->tx_txg);
1157 1157 data_old = db->db_buf;
1158 1158 }
1159 1159 ASSERT(data_old != NULL);
1160 1160 }
1161 1161 dr->dt.dl.dr_data = data_old;
1162 1162 } else {
1163 1163 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1164 1164 list_create(&dr->dt.di.dr_children,
1165 1165 sizeof (dbuf_dirty_record_t),
1166 1166 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1167 1167 }
1168 1168 if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL)
1169 1169 dr->dr_accounted = db->db.db_size;
1170 1170 dr->dr_dbuf = db;
1171 1171 dr->dr_txg = tx->tx_txg;
1172 1172 dr->dr_next = *drp;
1173 1173 *drp = dr;
1174 1174
1175 1175 /*
1176 1176 * We could have been freed_in_flight between the dbuf_noread
1177 1177 * and dbuf_dirty. We win, as though the dbuf_noread() had
1178 1178 * happened after the free.
1179 1179 */
1180 1180 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1181 1181 db->db_blkid != DMU_SPILL_BLKID) {
1182 1182 mutex_enter(&dn->dn_mtx);
1183 1183 if (dn->dn_free_ranges[txgoff] != NULL) {
1184 1184 range_tree_clear(dn->dn_free_ranges[txgoff],
1185 1185 db->db_blkid, 1);
1186 1186 }
1187 1187 mutex_exit(&dn->dn_mtx);
1188 1188 db->db_freed_in_flight = FALSE;
1189 1189 }
1190 1190
1191 1191 /*
1192 1192 * This buffer is now part of this txg
1193 1193 */
1194 1194 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1195 1195 db->db_dirtycnt += 1;
1196 1196 ASSERT3U(db->db_dirtycnt, <=, 3);
1197 1197
1198 1198 mutex_exit(&db->db_mtx);
1199 1199
1200 1200 if (db->db_blkid == DMU_BONUS_BLKID ||
1201 1201 db->db_blkid == DMU_SPILL_BLKID) {
1202 1202 mutex_enter(&dn->dn_mtx);
1203 1203 ASSERT(!list_link_active(&dr->dr_dirty_node));
1204 1204 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1205 1205 mutex_exit(&dn->dn_mtx);
1206 1206 dnode_setdirty(dn, tx);
1207 1207 DB_DNODE_EXIT(db);
1208 1208 return (dr);
1209 1209 } else if (do_free_accounting) {
1210 1210 blkptr_t *bp = db->db_blkptr;
1211 1211 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1212 1212 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1213 1213 /*
1214 1214 * This is only a guess -- if the dbuf is dirty
1215 1215 * in a previous txg, we don't know how much
1216 1216 * space it will use on disk yet. We should
1217 1217 * really have the struct_rwlock to access
1218 1218 * db_blkptr, but since this is just a guess,
1219 1219 * it's OK if we get an odd answer.
1220 1220 */
1221 1221 ddt_prefetch(os->os_spa, bp);
1222 1222 dnode_willuse_space(dn, -willfree, tx);
1223 1223 }
1224 1224
1225 1225 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1226 1226 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1227 1227 drop_struct_lock = TRUE;
1228 1228 }
1229 1229
1230 1230 if (db->db_level == 0) {
1231 1231 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1232 1232 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1233 1233 }
1234 1234
1235 1235 if (db->db_level+1 < dn->dn_nlevels) {
1236 1236 dmu_buf_impl_t *parent = db->db_parent;
1237 1237 dbuf_dirty_record_t *di;
1238 1238 int parent_held = FALSE;
1239 1239
1240 1240 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1241 1241 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1242 1242
1243 1243 parent = dbuf_hold_level(dn, db->db_level+1,
1244 1244 db->db_blkid >> epbs, FTAG);
1245 1245 ASSERT(parent != NULL);
1246 1246 parent_held = TRUE;
1247 1247 }
1248 1248 if (drop_struct_lock)
1249 1249 rw_exit(&dn->dn_struct_rwlock);
1250 1250 ASSERT3U(db->db_level+1, ==, parent->db_level);
1251 1251 di = dbuf_dirty(parent, tx);
1252 1252 if (parent_held)
1253 1253 dbuf_rele(parent, FTAG);
1254 1254
1255 1255 mutex_enter(&db->db_mtx);
1256 1256 /*
1257 1257 * Since we've dropped the mutex, it's possible that
1258 1258 * dbuf_undirty() might have changed this out from under us.
1259 1259 */
1260 1260 if (db->db_last_dirty == dr ||
1261 1261 dn->dn_object == DMU_META_DNODE_OBJECT) {
1262 1262 mutex_enter(&di->dt.di.dr_mtx);
1263 1263 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1264 1264 ASSERT(!list_link_active(&dr->dr_dirty_node));
1265 1265 list_insert_tail(&di->dt.di.dr_children, dr);
1266 1266 mutex_exit(&di->dt.di.dr_mtx);
1267 1267 dr->dr_parent = di;
1268 1268 }
1269 1269 mutex_exit(&db->db_mtx);
1270 1270 } else {
1271 1271 ASSERT(db->db_level+1 == dn->dn_nlevels);
1272 1272 ASSERT(db->db_blkid < dn->dn_nblkptr);
1273 1273 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1274 1274 mutex_enter(&dn->dn_mtx);
1275 1275 ASSERT(!list_link_active(&dr->dr_dirty_node));
1276 1276 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1277 1277 mutex_exit(&dn->dn_mtx);
1278 1278 if (drop_struct_lock)
1279 1279 rw_exit(&dn->dn_struct_rwlock);
1280 1280 }
1281 1281
1282 1282 dnode_setdirty(dn, tx);
1283 1283 DB_DNODE_EXIT(db);
1284 1284 return (dr);
1285 1285 }
1286 1286
1287 1287 /*
1288 1288 * Undirty a buffer in the transaction group referenced by the given
1289 1289 * transaction. Return whether this evicted the dbuf.
1290 1290 */
1291 1291 static boolean_t
1292 1292 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1293 1293 {
1294 1294 dnode_t *dn;
1295 1295 uint64_t txg = tx->tx_txg;
1296 1296 dbuf_dirty_record_t *dr, **drp;
1297 1297
1298 1298 ASSERT(txg != 0);
1299 1299 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1300 1300 ASSERT0(db->db_level);
1301 1301 ASSERT(MUTEX_HELD(&db->db_mtx));
1302 1302
1303 1303 /*
1304 1304 * If this buffer is not dirty, we're done.
1305 1305 */
1306 1306 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1307 1307 if (dr->dr_txg <= txg)
1308 1308 break;
1309 1309 if (dr == NULL || dr->dr_txg < txg)
1310 1310 return (B_FALSE);
1311 1311 ASSERT(dr->dr_txg == txg);
1312 1312 ASSERT(dr->dr_dbuf == db);
1313 1313
1314 1314 DB_DNODE_ENTER(db);
1315 1315 dn = DB_DNODE(db);
1316 1316
1317 1317 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1318 1318
1319 1319 ASSERT(db->db.db_size != 0);
1320 1320
1321 1321 /*
1322 1322 * Any space we accounted for in dp_dirty_* will be cleaned up by
1323 1323 * dsl_pool_sync(). This is relatively rare so the discrepancy
1324 1324 * is not a big deal.
1325 1325 */
1326 1326
1327 1327 *drp = dr->dr_next;
1328 1328
1329 1329 /*
1330 1330 * Note that there are three places in dbuf_dirty()
1331 1331 * where this dirty record may be put on a list.
1332 1332 * Make sure to do a list_remove corresponding to
1333 1333 * every one of those list_insert calls.
1334 1334 */
1335 1335 if (dr->dr_parent) {
1336 1336 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1337 1337 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1338 1338 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1339 1339 } else if (db->db_blkid == DMU_SPILL_BLKID ||
1340 1340 db->db_level+1 == dn->dn_nlevels) {
1341 1341 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1342 1342 mutex_enter(&dn->dn_mtx);
1343 1343 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1344 1344 mutex_exit(&dn->dn_mtx);
1345 1345 }
1346 1346 DB_DNODE_EXIT(db);
1347 1347
1348 1348 if (db->db_state != DB_NOFILL) {
1349 1349 dbuf_unoverride(dr);
1350 1350
1351 1351 ASSERT(db->db_buf != NULL);
1352 1352 ASSERT(dr->dt.dl.dr_data != NULL);
1353 1353 if (dr->dt.dl.dr_data != db->db_buf)
1354 1354 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1355 1355 }
1356 1356
1357 1357 if (db->db_level != 0) {
1358 1358 mutex_destroy(&dr->dt.di.dr_mtx);
1359 1359 list_destroy(&dr->dt.di.dr_children);
1360 1360 }
1361 1361
1362 1362 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1363 1363
1364 1364 ASSERT(db->db_dirtycnt > 0);
1365 1365 db->db_dirtycnt -= 1;
1366 1366
1367 1367 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1368 1368 arc_buf_t *buf = db->db_buf;
1369 1369
1370 1370 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1371 1371 dbuf_set_data(db, NULL);
1372 1372 VERIFY(arc_buf_remove_ref(buf, db));
1373 1373 dbuf_evict(db);
1374 1374 return (B_TRUE);
1375 1375 }
1376 1376
1377 1377 return (B_FALSE);
1378 1378 }
1379 1379
1380 1380 void
1381 1381 dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx)
1382 1382 {
1383 1383 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1384 1384 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1385 1385
1386 1386 ASSERT(tx->tx_txg != 0);
1387 1387 ASSERT(!refcount_is_zero(&db->db_holds));
1388 1388
1389 1389 DB_DNODE_ENTER(db);
1390 1390 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1391 1391 rf |= DB_RF_HAVESTRUCT;
1392 1392 DB_DNODE_EXIT(db);
1393 1393 (void) dbuf_read(db, NULL, rf);
1394 1394 (void) dbuf_dirty(db, tx);
1395 1395 }
1396 1396
1397 1397 void
1398 1398 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1399 1399 {
1400 1400 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1401 1401
1402 1402 db->db_state = DB_NOFILL;
1403 1403
1404 1404 dmu_buf_will_fill(db_fake, tx);
1405 1405 }
1406 1406
1407 1407 void
1408 1408 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1409 1409 {
1410 1410 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1411 1411
1412 1412 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1413 1413 ASSERT(tx->tx_txg != 0);
1414 1414 ASSERT(db->db_level == 0);
1415 1415 ASSERT(!refcount_is_zero(&db->db_holds));
1416 1416
1417 1417 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1418 1418 dmu_tx_private_ok(tx));
1419 1419
1420 1420 dbuf_noread(db);
1421 1421 (void) dbuf_dirty(db, tx);
1422 1422 }
1423 1423
1424 1424 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1425 1425 /* ARGSUSED */
1426 1426 void
1427 1427 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1428 1428 {
1429 1429 mutex_enter(&db->db_mtx);
1430 1430 DBUF_VERIFY(db);
1431 1431
1432 1432 if (db->db_state == DB_FILL) {
1433 1433 if (db->db_level == 0 && db->db_freed_in_flight) {
1434 1434 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1435 1435 /* we were freed while filling */
1436 1436 /* XXX dbuf_undirty? */
1437 1437 bzero(db->db.db_data, db->db.db_size);
1438 1438 db->db_freed_in_flight = FALSE;
1439 1439 }
1440 1440 db->db_state = DB_CACHED;
1441 1441 cv_broadcast(&db->db_changed);
1442 1442 }
1443 1443 mutex_exit(&db->db_mtx);
1444 1444 }
1445 1445
1446 1446 void
1447 1447 dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
1448 1448 bp_embedded_type_t etype, enum zio_compress comp,
1449 1449 int uncompressed_size, int compressed_size, int byteorder,
1450 1450 dmu_tx_t *tx)
1451 1451 {
1452 1452 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
1453 1453 struct dirty_leaf *dl;
1454 1454 dmu_object_type_t type;
1455 1455
1456 1456 DB_DNODE_ENTER(db);
1457 1457 type = DB_DNODE(db)->dn_type;
1458 1458 DB_DNODE_EXIT(db);
1459 1459
1460 1460 ASSERT0(db->db_level);
1461 1461 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1462 1462
1463 1463 dmu_buf_will_not_fill(dbuf, tx);
1464 1464
1465 1465 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1466 1466 dl = &db->db_last_dirty->dt.dl;
1467 1467 encode_embedded_bp_compressed(&dl->dr_overridden_by,
1468 1468 data, comp, uncompressed_size, compressed_size);
1469 1469 BPE_SET_ETYPE(&dl->dr_overridden_by, etype);
1470 1470 BP_SET_TYPE(&dl->dr_overridden_by, type);
1471 1471 BP_SET_LEVEL(&dl->dr_overridden_by, 0);
1472 1472 BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder);
1473 1473
1474 1474 dl->dr_override_state = DR_OVERRIDDEN;
1475 1475 dl->dr_overridden_by.blk_birth = db->db_last_dirty->dr_txg;
1476 1476 }
1477 1477
1478 1478 /*
1479 1479 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1480 1480 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1481 1481 */
1482 1482 void
1483 1483 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1484 1484 {
1485 1485 ASSERT(!refcount_is_zero(&db->db_holds));
1486 1486 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1487 1487 ASSERT(db->db_level == 0);
1488 1488 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1489 1489 ASSERT(buf != NULL);
1490 1490 ASSERT(arc_buf_size(buf) == db->db.db_size);
1491 1491 ASSERT(tx->tx_txg != 0);
1492 1492
1493 1493 arc_return_buf(buf, db);
1494 1494 ASSERT(arc_released(buf));
1495 1495
1496 1496 mutex_enter(&db->db_mtx);
1497 1497
1498 1498 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1499 1499 cv_wait(&db->db_changed, &db->db_mtx);
1500 1500
1501 1501 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1502 1502
1503 1503 if (db->db_state == DB_CACHED &&
1504 1504 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1505 1505 mutex_exit(&db->db_mtx);
1506 1506 (void) dbuf_dirty(db, tx);
1507 1507 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1508 1508 VERIFY(arc_buf_remove_ref(buf, db));
1509 1509 xuio_stat_wbuf_copied();
1510 1510 return;
1511 1511 }
1512 1512
1513 1513 xuio_stat_wbuf_nocopy();
1514 1514 if (db->db_state == DB_CACHED) {
1515 1515 dbuf_dirty_record_t *dr = db->db_last_dirty;
1516 1516
1517 1517 ASSERT(db->db_buf != NULL);
1518 1518 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1519 1519 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1520 1520 if (!arc_released(db->db_buf)) {
1521 1521 ASSERT(dr->dt.dl.dr_override_state ==
1522 1522 DR_OVERRIDDEN);
1523 1523 arc_release(db->db_buf, db);
1524 1524 }
1525 1525 dr->dt.dl.dr_data = buf;
1526 1526 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1527 1527 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1528 1528 arc_release(db->db_buf, db);
1529 1529 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1530 1530 }
1531 1531 db->db_buf = NULL;
1532 1532 }
1533 1533 ASSERT(db->db_buf == NULL);
1534 1534 dbuf_set_data(db, buf);
1535 1535 db->db_state = DB_FILL;
1536 1536 mutex_exit(&db->db_mtx);
1537 1537 (void) dbuf_dirty(db, tx);
1538 1538 dmu_buf_fill_done(&db->db, tx);
1539 1539 }
1540 1540
1541 1541 /*
1542 1542 * "Clear" the contents of this dbuf. This will mark the dbuf
1543 1543 * EVICTING and clear *most* of its references. Unfortunately,
1544 1544 * when we are not holding the dn_dbufs_mtx, we can't clear the
1545 1545 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1546 1546 * in this case. For callers from the DMU we will usually see:
1547 1547 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1548 1548 * For the arc callback, we will usually see:
1549 1549 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1550 1550 * Sometimes, though, we will get a mix of these two:
1551 1551 * DMU: dbuf_clear()->arc_buf_evict()
1552 1552 * ARC: dbuf_do_evict()->dbuf_destroy()
1553 1553 */
1554 1554 void
1555 1555 dbuf_clear(dmu_buf_impl_t *db)
1556 1556 {
1557 1557 dnode_t *dn;
1558 1558 dmu_buf_impl_t *parent = db->db_parent;
1559 1559 dmu_buf_impl_t *dndb;
1560 1560 int dbuf_gone = FALSE;
1561 1561
1562 1562 ASSERT(MUTEX_HELD(&db->db_mtx));
1563 1563 ASSERT(refcount_is_zero(&db->db_holds));
1564 1564
1565 1565 dbuf_evict_user(db);
1566 1566
1567 1567 if (db->db_state == DB_CACHED) {
1568 1568 ASSERT(db->db.db_data != NULL);
1569 1569 if (db->db_blkid == DMU_BONUS_BLKID) {
1570 1570 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1571 1571 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1572 1572 }
1573 1573 db->db.db_data = NULL;
1574 1574 db->db_state = DB_UNCACHED;
1575 1575 }
1576 1576
1577 1577 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
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1578 1578 ASSERT(db->db_data_pending == NULL);
1579 1579
1580 1580 db->db_state = DB_EVICTING;
1581 1581 db->db_blkptr = NULL;
1582 1582
1583 1583 DB_DNODE_ENTER(db);
1584 1584 dn = DB_DNODE(db);
1585 1585 dndb = dn->dn_dbuf;
1586 1586 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1587 1587 list_remove(&dn->dn_dbufs, db);
1588 - (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1588 + atomic_dec_32(&dn->dn_dbufs_count);
1589 1589 membar_producer();
1590 1590 DB_DNODE_EXIT(db);
1591 1591 /*
1592 1592 * Decrementing the dbuf count means that the hold corresponding
1593 1593 * to the removed dbuf is no longer discounted in dnode_move(),
1594 1594 * so the dnode cannot be moved until after we release the hold.
1595 1595 * The membar_producer() ensures visibility of the decremented
1596 1596 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1597 1597 * release any lock.
1598 1598 */
1599 1599 dnode_rele(dn, db);
1600 1600 db->db_dnode_handle = NULL;
1601 1601 } else {
1602 1602 DB_DNODE_EXIT(db);
1603 1603 }
1604 1604
1605 1605 if (db->db_buf)
1606 1606 dbuf_gone = arc_buf_evict(db->db_buf);
1607 1607
1608 1608 if (!dbuf_gone)
1609 1609 mutex_exit(&db->db_mtx);
1610 1610
1611 1611 /*
1612 1612 * If this dbuf is referenced from an indirect dbuf,
1613 1613 * decrement the ref count on the indirect dbuf.
1614 1614 */
1615 1615 if (parent && parent != dndb)
1616 1616 dbuf_rele(parent, db);
1617 1617 }
1618 1618
1619 1619 static int
1620 1620 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1621 1621 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1622 1622 {
1623 1623 int nlevels, epbs;
1624 1624
1625 1625 *parentp = NULL;
1626 1626 *bpp = NULL;
1627 1627
1628 1628 ASSERT(blkid != DMU_BONUS_BLKID);
1629 1629
1630 1630 if (blkid == DMU_SPILL_BLKID) {
1631 1631 mutex_enter(&dn->dn_mtx);
1632 1632 if (dn->dn_have_spill &&
1633 1633 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1634 1634 *bpp = &dn->dn_phys->dn_spill;
1635 1635 else
1636 1636 *bpp = NULL;
1637 1637 dbuf_add_ref(dn->dn_dbuf, NULL);
1638 1638 *parentp = dn->dn_dbuf;
1639 1639 mutex_exit(&dn->dn_mtx);
1640 1640 return (0);
1641 1641 }
1642 1642
1643 1643 if (dn->dn_phys->dn_nlevels == 0)
1644 1644 nlevels = 1;
1645 1645 else
1646 1646 nlevels = dn->dn_phys->dn_nlevels;
1647 1647
1648 1648 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1649 1649
1650 1650 ASSERT3U(level * epbs, <, 64);
1651 1651 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1652 1652 if (level >= nlevels ||
1653 1653 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1654 1654 /* the buffer has no parent yet */
1655 1655 return (SET_ERROR(ENOENT));
1656 1656 } else if (level < nlevels-1) {
1657 1657 /* this block is referenced from an indirect block */
1658 1658 int err = dbuf_hold_impl(dn, level+1,
1659 1659 blkid >> epbs, fail_sparse, NULL, parentp);
1660 1660 if (err)
1661 1661 return (err);
1662 1662 err = dbuf_read(*parentp, NULL,
1663 1663 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1664 1664 if (err) {
1665 1665 dbuf_rele(*parentp, NULL);
1666 1666 *parentp = NULL;
1667 1667 return (err);
1668 1668 }
1669 1669 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1670 1670 (blkid & ((1ULL << epbs) - 1));
1671 1671 return (0);
1672 1672 } else {
1673 1673 /* the block is referenced from the dnode */
1674 1674 ASSERT3U(level, ==, nlevels-1);
1675 1675 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1676 1676 blkid < dn->dn_phys->dn_nblkptr);
1677 1677 if (dn->dn_dbuf) {
1678 1678 dbuf_add_ref(dn->dn_dbuf, NULL);
1679 1679 *parentp = dn->dn_dbuf;
1680 1680 }
1681 1681 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1682 1682 return (0);
1683 1683 }
1684 1684 }
1685 1685
1686 1686 static dmu_buf_impl_t *
1687 1687 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1688 1688 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1689 1689 {
1690 1690 objset_t *os = dn->dn_objset;
1691 1691 dmu_buf_impl_t *db, *odb;
1692 1692
1693 1693 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1694 1694 ASSERT(dn->dn_type != DMU_OT_NONE);
1695 1695
1696 1696 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1697 1697
1698 1698 db->db_objset = os;
1699 1699 db->db.db_object = dn->dn_object;
1700 1700 db->db_level = level;
1701 1701 db->db_blkid = blkid;
1702 1702 db->db_last_dirty = NULL;
1703 1703 db->db_dirtycnt = 0;
1704 1704 db->db_dnode_handle = dn->dn_handle;
1705 1705 db->db_parent = parent;
1706 1706 db->db_blkptr = blkptr;
1707 1707
1708 1708 db->db_user_ptr = NULL;
1709 1709 db->db_user_data_ptr_ptr = NULL;
1710 1710 db->db_evict_func = NULL;
1711 1711 db->db_immediate_evict = 0;
1712 1712 db->db_freed_in_flight = 0;
1713 1713
1714 1714 if (blkid == DMU_BONUS_BLKID) {
1715 1715 ASSERT3P(parent, ==, dn->dn_dbuf);
1716 1716 db->db.db_size = DN_MAX_BONUSLEN -
1717 1717 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1718 1718 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1719 1719 db->db.db_offset = DMU_BONUS_BLKID;
1720 1720 db->db_state = DB_UNCACHED;
1721 1721 /* the bonus dbuf is not placed in the hash table */
1722 1722 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1723 1723 return (db);
1724 1724 } else if (blkid == DMU_SPILL_BLKID) {
1725 1725 db->db.db_size = (blkptr != NULL) ?
1726 1726 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1727 1727 db->db.db_offset = 0;
1728 1728 } else {
1729 1729 int blocksize =
1730 1730 db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz;
1731 1731 db->db.db_size = blocksize;
1732 1732 db->db.db_offset = db->db_blkid * blocksize;
1733 1733 }
1734 1734
1735 1735 /*
1736 1736 * Hold the dn_dbufs_mtx while we get the new dbuf
1737 1737 * in the hash table *and* added to the dbufs list.
1738 1738 * This prevents a possible deadlock with someone
1739 1739 * trying to look up this dbuf before its added to the
1740 1740 * dn_dbufs list.
1741 1741 */
1742 1742 mutex_enter(&dn->dn_dbufs_mtx);
1743 1743 db->db_state = DB_EVICTING;
1744 1744 if ((odb = dbuf_hash_insert(db)) != NULL) {
1745 1745 /* someone else inserted it first */
1746 1746 kmem_cache_free(dbuf_cache, db);
1747 1747 mutex_exit(&dn->dn_dbufs_mtx);
1748 1748 return (odb);
1749 1749 }
1750 1750 list_insert_head(&dn->dn_dbufs, db);
1751 1751 if (db->db_level == 0 && db->db_blkid >=
1752 1752 dn->dn_unlisted_l0_blkid)
1753 1753 dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
1754 1754 db->db_state = DB_UNCACHED;
1755 1755 mutex_exit(&dn->dn_dbufs_mtx);
1756 1756 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1757 1757
1758 1758 if (parent && parent != dn->dn_dbuf)
1759 1759 dbuf_add_ref(parent, db);
1760 1760
1761 1761 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1762 1762 refcount_count(&dn->dn_holds) > 0);
1763 1763 (void) refcount_add(&dn->dn_holds, db);
1764 1764 (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
1765 1765
1766 1766 dprintf_dbuf(db, "db=%p\n", db);
1767 1767
1768 1768 return (db);
1769 1769 }
1770 1770
1771 1771 static int
1772 1772 dbuf_do_evict(void *private)
1773 1773 {
1774 1774 arc_buf_t *buf = private;
1775 1775 dmu_buf_impl_t *db = buf->b_private;
1776 1776
1777 1777 if (!MUTEX_HELD(&db->db_mtx))
1778 1778 mutex_enter(&db->db_mtx);
1779 1779
1780 1780 ASSERT(refcount_is_zero(&db->db_holds));
1781 1781
1782 1782 if (db->db_state != DB_EVICTING) {
1783 1783 ASSERT(db->db_state == DB_CACHED);
1784 1784 DBUF_VERIFY(db);
1785 1785 db->db_buf = NULL;
1786 1786 dbuf_evict(db);
1787 1787 } else {
1788 1788 mutex_exit(&db->db_mtx);
1789 1789 dbuf_destroy(db);
1790 1790 }
1791 1791 return (0);
1792 1792 }
1793 1793
1794 1794 static void
1795 1795 dbuf_destroy(dmu_buf_impl_t *db)
1796 1796 {
1797 1797 ASSERT(refcount_is_zero(&db->db_holds));
1798 1798
1799 1799 if (db->db_blkid != DMU_BONUS_BLKID) {
1800 1800 /*
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1801 1801 * If this dbuf is still on the dn_dbufs list,
1802 1802 * remove it from that list.
1803 1803 */
1804 1804 if (db->db_dnode_handle != NULL) {
1805 1805 dnode_t *dn;
1806 1806
1807 1807 DB_DNODE_ENTER(db);
1808 1808 dn = DB_DNODE(db);
1809 1809 mutex_enter(&dn->dn_dbufs_mtx);
1810 1810 list_remove(&dn->dn_dbufs, db);
1811 - (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1811 + atomic_dec_32(&dn->dn_dbufs_count);
1812 1812 mutex_exit(&dn->dn_dbufs_mtx);
1813 1813 DB_DNODE_EXIT(db);
1814 1814 /*
1815 1815 * Decrementing the dbuf count means that the hold
1816 1816 * corresponding to the removed dbuf is no longer
1817 1817 * discounted in dnode_move(), so the dnode cannot be
1818 1818 * moved until after we release the hold.
1819 1819 */
1820 1820 dnode_rele(dn, db);
1821 1821 db->db_dnode_handle = NULL;
1822 1822 }
1823 1823 dbuf_hash_remove(db);
1824 1824 }
1825 1825 db->db_parent = NULL;
1826 1826 db->db_buf = NULL;
1827 1827
1828 1828 ASSERT(!list_link_active(&db->db_link));
1829 1829 ASSERT(db->db.db_data == NULL);
1830 1830 ASSERT(db->db_hash_next == NULL);
1831 1831 ASSERT(db->db_blkptr == NULL);
1832 1832 ASSERT(db->db_data_pending == NULL);
1833 1833
1834 1834 kmem_cache_free(dbuf_cache, db);
1835 1835 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1836 1836 }
1837 1837
1838 1838 void
1839 1839 dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio)
1840 1840 {
1841 1841 dmu_buf_impl_t *db = NULL;
1842 1842 blkptr_t *bp = NULL;
1843 1843
1844 1844 ASSERT(blkid != DMU_BONUS_BLKID);
1845 1845 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1846 1846
1847 1847 if (dnode_block_freed(dn, blkid))
1848 1848 return;
1849 1849
1850 1850 /* dbuf_find() returns with db_mtx held */
1851 1851 if (db = dbuf_find(dn, 0, blkid)) {
1852 1852 /*
1853 1853 * This dbuf is already in the cache. We assume that
1854 1854 * it is already CACHED, or else about to be either
1855 1855 * read or filled.
1856 1856 */
1857 1857 mutex_exit(&db->db_mtx);
1858 1858 return;
1859 1859 }
1860 1860
1861 1861 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1862 1862 if (bp && !BP_IS_HOLE(bp) && !BP_IS_EMBEDDED(bp)) {
1863 1863 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1864 1864 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1865 1865 zbookmark_phys_t zb;
1866 1866
1867 1867 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1868 1868 dn->dn_object, 0, blkid);
1869 1869
1870 1870 (void) arc_read(NULL, dn->dn_objset->os_spa,
1871 1871 bp, NULL, NULL, prio,
1872 1872 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1873 1873 &aflags, &zb);
1874 1874 }
1875 1875 if (db)
1876 1876 dbuf_rele(db, NULL);
1877 1877 }
1878 1878 }
1879 1879
1880 1880 /*
1881 1881 * Returns with db_holds incremented, and db_mtx not held.
1882 1882 * Note: dn_struct_rwlock must be held.
1883 1883 */
1884 1884 int
1885 1885 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1886 1886 void *tag, dmu_buf_impl_t **dbp)
1887 1887 {
1888 1888 dmu_buf_impl_t *db, *parent = NULL;
1889 1889
1890 1890 ASSERT(blkid != DMU_BONUS_BLKID);
1891 1891 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1892 1892 ASSERT3U(dn->dn_nlevels, >, level);
1893 1893
1894 1894 *dbp = NULL;
1895 1895 top:
1896 1896 /* dbuf_find() returns with db_mtx held */
1897 1897 db = dbuf_find(dn, level, blkid);
1898 1898
1899 1899 if (db == NULL) {
1900 1900 blkptr_t *bp = NULL;
1901 1901 int err;
1902 1902
1903 1903 ASSERT3P(parent, ==, NULL);
1904 1904 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1905 1905 if (fail_sparse) {
1906 1906 if (err == 0 && bp && BP_IS_HOLE(bp))
1907 1907 err = SET_ERROR(ENOENT);
1908 1908 if (err) {
1909 1909 if (parent)
1910 1910 dbuf_rele(parent, NULL);
1911 1911 return (err);
1912 1912 }
1913 1913 }
1914 1914 if (err && err != ENOENT)
1915 1915 return (err);
1916 1916 db = dbuf_create(dn, level, blkid, parent, bp);
1917 1917 }
1918 1918
1919 1919 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1920 1920 arc_buf_add_ref(db->db_buf, db);
1921 1921 if (db->db_buf->b_data == NULL) {
1922 1922 dbuf_clear(db);
1923 1923 if (parent) {
1924 1924 dbuf_rele(parent, NULL);
1925 1925 parent = NULL;
1926 1926 }
1927 1927 goto top;
1928 1928 }
1929 1929 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1930 1930 }
1931 1931
1932 1932 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1933 1933
1934 1934 /*
1935 1935 * If this buffer is currently syncing out, and we are are
1936 1936 * still referencing it from db_data, we need to make a copy
1937 1937 * of it in case we decide we want to dirty it again in this txg.
1938 1938 */
1939 1939 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1940 1940 dn->dn_object != DMU_META_DNODE_OBJECT &&
1941 1941 db->db_state == DB_CACHED && db->db_data_pending) {
1942 1942 dbuf_dirty_record_t *dr = db->db_data_pending;
1943 1943
1944 1944 if (dr->dt.dl.dr_data == db->db_buf) {
1945 1945 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1946 1946
1947 1947 dbuf_set_data(db,
1948 1948 arc_buf_alloc(dn->dn_objset->os_spa,
1949 1949 db->db.db_size, db, type));
1950 1950 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1951 1951 db->db.db_size);
1952 1952 }
1953 1953 }
1954 1954
1955 1955 (void) refcount_add(&db->db_holds, tag);
1956 1956 dbuf_update_data(db);
1957 1957 DBUF_VERIFY(db);
1958 1958 mutex_exit(&db->db_mtx);
1959 1959
1960 1960 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1961 1961 if (parent)
1962 1962 dbuf_rele(parent, NULL);
1963 1963
1964 1964 ASSERT3P(DB_DNODE(db), ==, dn);
1965 1965 ASSERT3U(db->db_blkid, ==, blkid);
1966 1966 ASSERT3U(db->db_level, ==, level);
1967 1967 *dbp = db;
1968 1968
1969 1969 return (0);
1970 1970 }
1971 1971
1972 1972 dmu_buf_impl_t *
1973 1973 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1974 1974 {
1975 1975 dmu_buf_impl_t *db;
1976 1976 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1977 1977 return (err ? NULL : db);
1978 1978 }
1979 1979
1980 1980 dmu_buf_impl_t *
1981 1981 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1982 1982 {
1983 1983 dmu_buf_impl_t *db;
1984 1984 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1985 1985 return (err ? NULL : db);
1986 1986 }
1987 1987
1988 1988 void
1989 1989 dbuf_create_bonus(dnode_t *dn)
1990 1990 {
1991 1991 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1992 1992
1993 1993 ASSERT(dn->dn_bonus == NULL);
1994 1994 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
1995 1995 }
1996 1996
1997 1997 int
1998 1998 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
1999 1999 {
2000 2000 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2001 2001 dnode_t *dn;
2002 2002
2003 2003 if (db->db_blkid != DMU_SPILL_BLKID)
2004 2004 return (SET_ERROR(ENOTSUP));
2005 2005 if (blksz == 0)
2006 2006 blksz = SPA_MINBLOCKSIZE;
2007 2007 if (blksz > SPA_MAXBLOCKSIZE)
2008 2008 blksz = SPA_MAXBLOCKSIZE;
2009 2009 else
2010 2010 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
2011 2011
2012 2012 DB_DNODE_ENTER(db);
2013 2013 dn = DB_DNODE(db);
2014 2014 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
2015 2015 dbuf_new_size(db, blksz, tx);
2016 2016 rw_exit(&dn->dn_struct_rwlock);
2017 2017 DB_DNODE_EXIT(db);
2018 2018
2019 2019 return (0);
2020 2020 }
2021 2021
2022 2022 void
2023 2023 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2024 2024 {
2025 2025 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2026 2026 }
2027 2027
2028 2028 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2029 2029 void
2030 2030 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2031 2031 {
2032 2032 int64_t holds = refcount_add(&db->db_holds, tag);
2033 2033 ASSERT(holds > 1);
2034 2034 }
2035 2035
2036 2036 /*
2037 2037 * If you call dbuf_rele() you had better not be referencing the dnode handle
2038 2038 * unless you have some other direct or indirect hold on the dnode. (An indirect
2039 2039 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2040 2040 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2041 2041 * dnode's parent dbuf evicting its dnode handles.
2042 2042 */
2043 2043 void
2044 2044 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2045 2045 {
2046 2046 mutex_enter(&db->db_mtx);
2047 2047 dbuf_rele_and_unlock(db, tag);
2048 2048 }
2049 2049
2050 2050 void
2051 2051 dmu_buf_rele(dmu_buf_t *db, void *tag)
2052 2052 {
2053 2053 dbuf_rele((dmu_buf_impl_t *)db, tag);
2054 2054 }
2055 2055
2056 2056 /*
2057 2057 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2058 2058 * db_dirtycnt and db_holds to be updated atomically.
2059 2059 */
2060 2060 void
2061 2061 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2062 2062 {
2063 2063 int64_t holds;
2064 2064
2065 2065 ASSERT(MUTEX_HELD(&db->db_mtx));
2066 2066 DBUF_VERIFY(db);
2067 2067
2068 2068 /*
2069 2069 * Remove the reference to the dbuf before removing its hold on the
2070 2070 * dnode so we can guarantee in dnode_move() that a referenced bonus
2071 2071 * buffer has a corresponding dnode hold.
2072 2072 */
2073 2073 holds = refcount_remove(&db->db_holds, tag);
2074 2074 ASSERT(holds >= 0);
2075 2075
2076 2076 /*
2077 2077 * We can't freeze indirects if there is a possibility that they
2078 2078 * may be modified in the current syncing context.
2079 2079 */
2080 2080 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2081 2081 arc_buf_freeze(db->db_buf);
2082 2082
2083 2083 if (holds == db->db_dirtycnt &&
2084 2084 db->db_level == 0 && db->db_immediate_evict)
2085 2085 dbuf_evict_user(db);
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2086 2086
2087 2087 if (holds == 0) {
2088 2088 if (db->db_blkid == DMU_BONUS_BLKID) {
2089 2089 mutex_exit(&db->db_mtx);
2090 2090
2091 2091 /*
2092 2092 * If the dnode moves here, we cannot cross this barrier
2093 2093 * until the move completes.
2094 2094 */
2095 2095 DB_DNODE_ENTER(db);
2096 - (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
2096 + atomic_dec_32(&DB_DNODE(db)->dn_dbufs_count);
2097 2097 DB_DNODE_EXIT(db);
2098 2098 /*
2099 2099 * The bonus buffer's dnode hold is no longer discounted
2100 2100 * in dnode_move(). The dnode cannot move until after
2101 2101 * the dnode_rele().
2102 2102 */
2103 2103 dnode_rele(DB_DNODE(db), db);
2104 2104 } else if (db->db_buf == NULL) {
2105 2105 /*
2106 2106 * This is a special case: we never associated this
2107 2107 * dbuf with any data allocated from the ARC.
2108 2108 */
2109 2109 ASSERT(db->db_state == DB_UNCACHED ||
2110 2110 db->db_state == DB_NOFILL);
2111 2111 dbuf_evict(db);
2112 2112 } else if (arc_released(db->db_buf)) {
2113 2113 arc_buf_t *buf = db->db_buf;
2114 2114 /*
2115 2115 * This dbuf has anonymous data associated with it.
2116 2116 */
2117 2117 dbuf_set_data(db, NULL);
2118 2118 VERIFY(arc_buf_remove_ref(buf, db));
2119 2119 dbuf_evict(db);
2120 2120 } else {
2121 2121 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2122 2122
2123 2123 /*
2124 2124 * A dbuf will be eligible for eviction if either the
2125 2125 * 'primarycache' property is set or a duplicate
2126 2126 * copy of this buffer is already cached in the arc.
2127 2127 *
2128 2128 * In the case of the 'primarycache' a buffer
2129 2129 * is considered for eviction if it matches the
2130 2130 * criteria set in the property.
2131 2131 *
2132 2132 * To decide if our buffer is considered a
2133 2133 * duplicate, we must call into the arc to determine
2134 2134 * if multiple buffers are referencing the same
2135 2135 * block on-disk. If so, then we simply evict
2136 2136 * ourselves.
2137 2137 */
2138 2138 if (!DBUF_IS_CACHEABLE(db) ||
2139 2139 arc_buf_eviction_needed(db->db_buf))
2140 2140 dbuf_clear(db);
2141 2141 else
2142 2142 mutex_exit(&db->db_mtx);
2143 2143 }
2144 2144 } else {
2145 2145 mutex_exit(&db->db_mtx);
2146 2146 }
2147 2147 }
2148 2148
2149 2149 #pragma weak dmu_buf_refcount = dbuf_refcount
2150 2150 uint64_t
2151 2151 dbuf_refcount(dmu_buf_impl_t *db)
2152 2152 {
2153 2153 return (refcount_count(&db->db_holds));
2154 2154 }
2155 2155
2156 2156 void *
2157 2157 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2158 2158 dmu_buf_evict_func_t *evict_func)
2159 2159 {
2160 2160 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2161 2161 user_data_ptr_ptr, evict_func));
2162 2162 }
2163 2163
2164 2164 void *
2165 2165 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2166 2166 dmu_buf_evict_func_t *evict_func)
2167 2167 {
2168 2168 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2169 2169
2170 2170 db->db_immediate_evict = TRUE;
2171 2171 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2172 2172 user_data_ptr_ptr, evict_func));
2173 2173 }
2174 2174
2175 2175 void *
2176 2176 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2177 2177 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
2178 2178 {
2179 2179 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2180 2180 ASSERT(db->db_level == 0);
2181 2181
2182 2182 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2183 2183
2184 2184 mutex_enter(&db->db_mtx);
2185 2185
2186 2186 if (db->db_user_ptr == old_user_ptr) {
2187 2187 db->db_user_ptr = user_ptr;
2188 2188 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
2189 2189 db->db_evict_func = evict_func;
2190 2190
2191 2191 dbuf_update_data(db);
2192 2192 } else {
2193 2193 old_user_ptr = db->db_user_ptr;
2194 2194 }
2195 2195
2196 2196 mutex_exit(&db->db_mtx);
2197 2197 return (old_user_ptr);
2198 2198 }
2199 2199
2200 2200 void *
2201 2201 dmu_buf_get_user(dmu_buf_t *db_fake)
2202 2202 {
2203 2203 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2204 2204 ASSERT(!refcount_is_zero(&db->db_holds));
2205 2205
2206 2206 return (db->db_user_ptr);
2207 2207 }
2208 2208
2209 2209 boolean_t
2210 2210 dmu_buf_freeable(dmu_buf_t *dbuf)
2211 2211 {
2212 2212 boolean_t res = B_FALSE;
2213 2213 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2214 2214
2215 2215 if (db->db_blkptr)
2216 2216 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2217 2217 db->db_blkptr, db->db_blkptr->blk_birth);
2218 2218
2219 2219 return (res);
2220 2220 }
2221 2221
2222 2222 blkptr_t *
2223 2223 dmu_buf_get_blkptr(dmu_buf_t *db)
2224 2224 {
2225 2225 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
2226 2226 return (dbi->db_blkptr);
2227 2227 }
2228 2228
2229 2229 static void
2230 2230 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2231 2231 {
2232 2232 /* ASSERT(dmu_tx_is_syncing(tx) */
2233 2233 ASSERT(MUTEX_HELD(&db->db_mtx));
2234 2234
2235 2235 if (db->db_blkptr != NULL)
2236 2236 return;
2237 2237
2238 2238 if (db->db_blkid == DMU_SPILL_BLKID) {
2239 2239 db->db_blkptr = &dn->dn_phys->dn_spill;
2240 2240 BP_ZERO(db->db_blkptr);
2241 2241 return;
2242 2242 }
2243 2243 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2244 2244 /*
2245 2245 * This buffer was allocated at a time when there was
2246 2246 * no available blkptrs from the dnode, or it was
2247 2247 * inappropriate to hook it in (i.e., nlevels mis-match).
2248 2248 */
2249 2249 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2250 2250 ASSERT(db->db_parent == NULL);
2251 2251 db->db_parent = dn->dn_dbuf;
2252 2252 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2253 2253 DBUF_VERIFY(db);
2254 2254 } else {
2255 2255 dmu_buf_impl_t *parent = db->db_parent;
2256 2256 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2257 2257
2258 2258 ASSERT(dn->dn_phys->dn_nlevels > 1);
2259 2259 if (parent == NULL) {
2260 2260 mutex_exit(&db->db_mtx);
2261 2261 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2262 2262 (void) dbuf_hold_impl(dn, db->db_level+1,
2263 2263 db->db_blkid >> epbs, FALSE, db, &parent);
2264 2264 rw_exit(&dn->dn_struct_rwlock);
2265 2265 mutex_enter(&db->db_mtx);
2266 2266 db->db_parent = parent;
2267 2267 }
2268 2268 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2269 2269 (db->db_blkid & ((1ULL << epbs) - 1));
2270 2270 DBUF_VERIFY(db);
2271 2271 }
2272 2272 }
2273 2273
2274 2274 static void
2275 2275 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2276 2276 {
2277 2277 dmu_buf_impl_t *db = dr->dr_dbuf;
2278 2278 dnode_t *dn;
2279 2279 zio_t *zio;
2280 2280
2281 2281 ASSERT(dmu_tx_is_syncing(tx));
2282 2282
2283 2283 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2284 2284
2285 2285 mutex_enter(&db->db_mtx);
2286 2286
2287 2287 ASSERT(db->db_level > 0);
2288 2288 DBUF_VERIFY(db);
2289 2289
2290 2290 /* Read the block if it hasn't been read yet. */
2291 2291 if (db->db_buf == NULL) {
2292 2292 mutex_exit(&db->db_mtx);
2293 2293 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2294 2294 mutex_enter(&db->db_mtx);
2295 2295 }
2296 2296 ASSERT3U(db->db_state, ==, DB_CACHED);
2297 2297 ASSERT(db->db_buf != NULL);
2298 2298
2299 2299 DB_DNODE_ENTER(db);
2300 2300 dn = DB_DNODE(db);
2301 2301 /* Indirect block size must match what the dnode thinks it is. */
2302 2302 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2303 2303 dbuf_check_blkptr(dn, db);
2304 2304 DB_DNODE_EXIT(db);
2305 2305
2306 2306 /* Provide the pending dirty record to child dbufs */
2307 2307 db->db_data_pending = dr;
2308 2308
2309 2309 mutex_exit(&db->db_mtx);
2310 2310 dbuf_write(dr, db->db_buf, tx);
2311 2311
2312 2312 zio = dr->dr_zio;
2313 2313 mutex_enter(&dr->dt.di.dr_mtx);
2314 2314 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2315 2315 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2316 2316 mutex_exit(&dr->dt.di.dr_mtx);
2317 2317 zio_nowait(zio);
2318 2318 }
2319 2319
2320 2320 static void
2321 2321 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2322 2322 {
2323 2323 arc_buf_t **datap = &dr->dt.dl.dr_data;
2324 2324 dmu_buf_impl_t *db = dr->dr_dbuf;
2325 2325 dnode_t *dn;
2326 2326 objset_t *os;
2327 2327 uint64_t txg = tx->tx_txg;
2328 2328
2329 2329 ASSERT(dmu_tx_is_syncing(tx));
2330 2330
2331 2331 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2332 2332
2333 2333 mutex_enter(&db->db_mtx);
2334 2334 /*
2335 2335 * To be synced, we must be dirtied. But we
2336 2336 * might have been freed after the dirty.
2337 2337 */
2338 2338 if (db->db_state == DB_UNCACHED) {
2339 2339 /* This buffer has been freed since it was dirtied */
2340 2340 ASSERT(db->db.db_data == NULL);
2341 2341 } else if (db->db_state == DB_FILL) {
2342 2342 /* This buffer was freed and is now being re-filled */
2343 2343 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2344 2344 } else {
2345 2345 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2346 2346 }
2347 2347 DBUF_VERIFY(db);
2348 2348
2349 2349 DB_DNODE_ENTER(db);
2350 2350 dn = DB_DNODE(db);
2351 2351
2352 2352 if (db->db_blkid == DMU_SPILL_BLKID) {
2353 2353 mutex_enter(&dn->dn_mtx);
2354 2354 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2355 2355 mutex_exit(&dn->dn_mtx);
2356 2356 }
2357 2357
2358 2358 /*
2359 2359 * If this is a bonus buffer, simply copy the bonus data into the
2360 2360 * dnode. It will be written out when the dnode is synced (and it
2361 2361 * will be synced, since it must have been dirty for dbuf_sync to
2362 2362 * be called).
2363 2363 */
2364 2364 if (db->db_blkid == DMU_BONUS_BLKID) {
2365 2365 dbuf_dirty_record_t **drp;
2366 2366
2367 2367 ASSERT(*datap != NULL);
2368 2368 ASSERT0(db->db_level);
2369 2369 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2370 2370 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2371 2371 DB_DNODE_EXIT(db);
2372 2372
2373 2373 if (*datap != db->db.db_data) {
2374 2374 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2375 2375 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2376 2376 }
2377 2377 db->db_data_pending = NULL;
2378 2378 drp = &db->db_last_dirty;
2379 2379 while (*drp != dr)
2380 2380 drp = &(*drp)->dr_next;
2381 2381 ASSERT(dr->dr_next == NULL);
2382 2382 ASSERT(dr->dr_dbuf == db);
2383 2383 *drp = dr->dr_next;
2384 2384 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2385 2385 ASSERT(db->db_dirtycnt > 0);
2386 2386 db->db_dirtycnt -= 1;
2387 2387 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2388 2388 return;
2389 2389 }
2390 2390
2391 2391 os = dn->dn_objset;
2392 2392
2393 2393 /*
2394 2394 * This function may have dropped the db_mtx lock allowing a dmu_sync
2395 2395 * operation to sneak in. As a result, we need to ensure that we
2396 2396 * don't check the dr_override_state until we have returned from
2397 2397 * dbuf_check_blkptr.
2398 2398 */
2399 2399 dbuf_check_blkptr(dn, db);
2400 2400
2401 2401 /*
2402 2402 * If this buffer is in the middle of an immediate write,
2403 2403 * wait for the synchronous IO to complete.
2404 2404 */
2405 2405 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2406 2406 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2407 2407 cv_wait(&db->db_changed, &db->db_mtx);
2408 2408 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2409 2409 }
2410 2410
2411 2411 if (db->db_state != DB_NOFILL &&
2412 2412 dn->dn_object != DMU_META_DNODE_OBJECT &&
2413 2413 refcount_count(&db->db_holds) > 1 &&
2414 2414 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2415 2415 *datap == db->db_buf) {
2416 2416 /*
2417 2417 * If this buffer is currently "in use" (i.e., there
2418 2418 * are active holds and db_data still references it),
2419 2419 * then make a copy before we start the write so that
2420 2420 * any modifications from the open txg will not leak
2421 2421 * into this write.
2422 2422 *
2423 2423 * NOTE: this copy does not need to be made for
2424 2424 * objects only modified in the syncing context (e.g.
2425 2425 * DNONE_DNODE blocks).
2426 2426 */
2427 2427 int blksz = arc_buf_size(*datap);
2428 2428 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2429 2429 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2430 2430 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2431 2431 }
2432 2432 db->db_data_pending = dr;
2433 2433
2434 2434 mutex_exit(&db->db_mtx);
2435 2435
2436 2436 dbuf_write(dr, *datap, tx);
2437 2437
2438 2438 ASSERT(!list_link_active(&dr->dr_dirty_node));
2439 2439 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2440 2440 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2441 2441 DB_DNODE_EXIT(db);
2442 2442 } else {
2443 2443 /*
2444 2444 * Although zio_nowait() does not "wait for an IO", it does
2445 2445 * initiate the IO. If this is an empty write it seems plausible
2446 2446 * that the IO could actually be completed before the nowait
2447 2447 * returns. We need to DB_DNODE_EXIT() first in case
2448 2448 * zio_nowait() invalidates the dbuf.
2449 2449 */
2450 2450 DB_DNODE_EXIT(db);
2451 2451 zio_nowait(dr->dr_zio);
2452 2452 }
2453 2453 }
2454 2454
2455 2455 void
2456 2456 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2457 2457 {
2458 2458 dbuf_dirty_record_t *dr;
2459 2459
2460 2460 while (dr = list_head(list)) {
2461 2461 if (dr->dr_zio != NULL) {
2462 2462 /*
2463 2463 * If we find an already initialized zio then we
2464 2464 * are processing the meta-dnode, and we have finished.
2465 2465 * The dbufs for all dnodes are put back on the list
2466 2466 * during processing, so that we can zio_wait()
2467 2467 * these IOs after initiating all child IOs.
2468 2468 */
2469 2469 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2470 2470 DMU_META_DNODE_OBJECT);
2471 2471 break;
2472 2472 }
2473 2473 list_remove(list, dr);
2474 2474 if (dr->dr_dbuf->db_level > 0)
2475 2475 dbuf_sync_indirect(dr, tx);
2476 2476 else
2477 2477 dbuf_sync_leaf(dr, tx);
2478 2478 }
2479 2479 }
2480 2480
2481 2481 /* ARGSUSED */
2482 2482 static void
2483 2483 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2484 2484 {
2485 2485 dmu_buf_impl_t *db = vdb;
2486 2486 dnode_t *dn;
2487 2487 blkptr_t *bp = zio->io_bp;
2488 2488 blkptr_t *bp_orig = &zio->io_bp_orig;
2489 2489 spa_t *spa = zio->io_spa;
2490 2490 int64_t delta;
2491 2491 uint64_t fill = 0;
2492 2492 int i;
2493 2493
2494 2494 ASSERT3P(db->db_blkptr, ==, bp);
2495 2495
2496 2496 DB_DNODE_ENTER(db);
2497 2497 dn = DB_DNODE(db);
2498 2498 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2499 2499 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2500 2500 zio->io_prev_space_delta = delta;
2501 2501
2502 2502 if (bp->blk_birth != 0) {
2503 2503 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2504 2504 BP_GET_TYPE(bp) == dn->dn_type) ||
2505 2505 (db->db_blkid == DMU_SPILL_BLKID &&
2506 2506 BP_GET_TYPE(bp) == dn->dn_bonustype) ||
2507 2507 BP_IS_EMBEDDED(bp));
2508 2508 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2509 2509 }
2510 2510
2511 2511 mutex_enter(&db->db_mtx);
2512 2512
2513 2513 #ifdef ZFS_DEBUG
2514 2514 if (db->db_blkid == DMU_SPILL_BLKID) {
2515 2515 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2516 2516 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2517 2517 db->db_blkptr == &dn->dn_phys->dn_spill);
2518 2518 }
2519 2519 #endif
2520 2520
2521 2521 if (db->db_level == 0) {
2522 2522 mutex_enter(&dn->dn_mtx);
2523 2523 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2524 2524 db->db_blkid != DMU_SPILL_BLKID)
2525 2525 dn->dn_phys->dn_maxblkid = db->db_blkid;
2526 2526 mutex_exit(&dn->dn_mtx);
2527 2527
2528 2528 if (dn->dn_type == DMU_OT_DNODE) {
2529 2529 dnode_phys_t *dnp = db->db.db_data;
2530 2530 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2531 2531 i--, dnp++) {
2532 2532 if (dnp->dn_type != DMU_OT_NONE)
2533 2533 fill++;
2534 2534 }
2535 2535 } else {
2536 2536 if (BP_IS_HOLE(bp)) {
2537 2537 fill = 0;
2538 2538 } else {
2539 2539 fill = 1;
2540 2540 }
2541 2541 }
2542 2542 } else {
2543 2543 blkptr_t *ibp = db->db.db_data;
2544 2544 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2545 2545 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2546 2546 if (BP_IS_HOLE(ibp))
2547 2547 continue;
2548 2548 fill += BP_GET_FILL(ibp);
2549 2549 }
2550 2550 }
2551 2551 DB_DNODE_EXIT(db);
2552 2552
2553 2553 if (!BP_IS_EMBEDDED(bp))
2554 2554 bp->blk_fill = fill;
2555 2555
2556 2556 mutex_exit(&db->db_mtx);
2557 2557 }
2558 2558
2559 2559 /*
2560 2560 * The SPA will call this callback several times for each zio - once
2561 2561 * for every physical child i/o (zio->io_phys_children times). This
2562 2562 * allows the DMU to monitor the progress of each logical i/o. For example,
2563 2563 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
2564 2564 * block. There may be a long delay before all copies/fragments are completed,
2565 2565 * so this callback allows us to retire dirty space gradually, as the physical
2566 2566 * i/os complete.
2567 2567 */
2568 2568 /* ARGSUSED */
2569 2569 static void
2570 2570 dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg)
2571 2571 {
2572 2572 dmu_buf_impl_t *db = arg;
2573 2573 objset_t *os = db->db_objset;
2574 2574 dsl_pool_t *dp = dmu_objset_pool(os);
2575 2575 dbuf_dirty_record_t *dr;
2576 2576 int delta = 0;
2577 2577
2578 2578 dr = db->db_data_pending;
2579 2579 ASSERT3U(dr->dr_txg, ==, zio->io_txg);
2580 2580
2581 2581 /*
2582 2582 * The callback will be called io_phys_children times. Retire one
2583 2583 * portion of our dirty space each time we are called. Any rounding
2584 2584 * error will be cleaned up by dsl_pool_sync()'s call to
2585 2585 * dsl_pool_undirty_space().
2586 2586 */
2587 2587 delta = dr->dr_accounted / zio->io_phys_children;
2588 2588 dsl_pool_undirty_space(dp, delta, zio->io_txg);
2589 2589 }
2590 2590
2591 2591 /* ARGSUSED */
2592 2592 static void
2593 2593 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2594 2594 {
2595 2595 dmu_buf_impl_t *db = vdb;
2596 2596 blkptr_t *bp_orig = &zio->io_bp_orig;
2597 2597 blkptr_t *bp = db->db_blkptr;
2598 2598 objset_t *os = db->db_objset;
2599 2599 dmu_tx_t *tx = os->os_synctx;
2600 2600 dbuf_dirty_record_t **drp, *dr;
2601 2601
2602 2602 ASSERT0(zio->io_error);
2603 2603 ASSERT(db->db_blkptr == bp);
2604 2604
2605 2605 /*
2606 2606 * For nopwrites and rewrites we ensure that the bp matches our
2607 2607 * original and bypass all the accounting.
2608 2608 */
2609 2609 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) {
2610 2610 ASSERT(BP_EQUAL(bp, bp_orig));
2611 2611 } else {
2612 2612 dsl_dataset_t *ds = os->os_dsl_dataset;
2613 2613 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2614 2614 dsl_dataset_block_born(ds, bp, tx);
2615 2615 }
2616 2616
2617 2617 mutex_enter(&db->db_mtx);
2618 2618
2619 2619 DBUF_VERIFY(db);
2620 2620
2621 2621 drp = &db->db_last_dirty;
2622 2622 while ((dr = *drp) != db->db_data_pending)
2623 2623 drp = &dr->dr_next;
2624 2624 ASSERT(!list_link_active(&dr->dr_dirty_node));
2625 2625 ASSERT(dr->dr_dbuf == db);
2626 2626 ASSERT(dr->dr_next == NULL);
2627 2627 *drp = dr->dr_next;
2628 2628
2629 2629 #ifdef ZFS_DEBUG
2630 2630 if (db->db_blkid == DMU_SPILL_BLKID) {
2631 2631 dnode_t *dn;
2632 2632
2633 2633 DB_DNODE_ENTER(db);
2634 2634 dn = DB_DNODE(db);
2635 2635 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2636 2636 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2637 2637 db->db_blkptr == &dn->dn_phys->dn_spill);
2638 2638 DB_DNODE_EXIT(db);
2639 2639 }
2640 2640 #endif
2641 2641
2642 2642 if (db->db_level == 0) {
2643 2643 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2644 2644 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2645 2645 if (db->db_state != DB_NOFILL) {
2646 2646 if (dr->dt.dl.dr_data != db->db_buf)
2647 2647 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2648 2648 db));
2649 2649 else if (!arc_released(db->db_buf))
2650 2650 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2651 2651 }
2652 2652 } else {
2653 2653 dnode_t *dn;
2654 2654
2655 2655 DB_DNODE_ENTER(db);
2656 2656 dn = DB_DNODE(db);
2657 2657 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2658 2658 ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift);
2659 2659 if (!BP_IS_HOLE(db->db_blkptr)) {
2660 2660 int epbs =
2661 2661 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2662 2662 ASSERT3U(db->db_blkid, <=,
2663 2663 dn->dn_phys->dn_maxblkid >> (db->db_level * epbs));
2664 2664 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2665 2665 db->db.db_size);
2666 2666 if (!arc_released(db->db_buf))
2667 2667 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2668 2668 }
2669 2669 DB_DNODE_EXIT(db);
2670 2670 mutex_destroy(&dr->dt.di.dr_mtx);
2671 2671 list_destroy(&dr->dt.di.dr_children);
2672 2672 }
2673 2673 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2674 2674
2675 2675 cv_broadcast(&db->db_changed);
2676 2676 ASSERT(db->db_dirtycnt > 0);
2677 2677 db->db_dirtycnt -= 1;
2678 2678 db->db_data_pending = NULL;
2679 2679 dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg);
2680 2680 }
2681 2681
2682 2682 static void
2683 2683 dbuf_write_nofill_ready(zio_t *zio)
2684 2684 {
2685 2685 dbuf_write_ready(zio, NULL, zio->io_private);
2686 2686 }
2687 2687
2688 2688 static void
2689 2689 dbuf_write_nofill_done(zio_t *zio)
2690 2690 {
2691 2691 dbuf_write_done(zio, NULL, zio->io_private);
2692 2692 }
2693 2693
2694 2694 static void
2695 2695 dbuf_write_override_ready(zio_t *zio)
2696 2696 {
2697 2697 dbuf_dirty_record_t *dr = zio->io_private;
2698 2698 dmu_buf_impl_t *db = dr->dr_dbuf;
2699 2699
2700 2700 dbuf_write_ready(zio, NULL, db);
2701 2701 }
2702 2702
2703 2703 static void
2704 2704 dbuf_write_override_done(zio_t *zio)
2705 2705 {
2706 2706 dbuf_dirty_record_t *dr = zio->io_private;
2707 2707 dmu_buf_impl_t *db = dr->dr_dbuf;
2708 2708 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2709 2709
2710 2710 mutex_enter(&db->db_mtx);
2711 2711 if (!BP_EQUAL(zio->io_bp, obp)) {
2712 2712 if (!BP_IS_HOLE(obp))
2713 2713 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2714 2714 arc_release(dr->dt.dl.dr_data, db);
2715 2715 }
2716 2716 mutex_exit(&db->db_mtx);
2717 2717
2718 2718 dbuf_write_done(zio, NULL, db);
2719 2719 }
2720 2720
2721 2721 /* Issue I/O to commit a dirty buffer to disk. */
2722 2722 static void
2723 2723 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2724 2724 {
2725 2725 dmu_buf_impl_t *db = dr->dr_dbuf;
2726 2726 dnode_t *dn;
2727 2727 objset_t *os;
2728 2728 dmu_buf_impl_t *parent = db->db_parent;
2729 2729 uint64_t txg = tx->tx_txg;
2730 2730 zbookmark_phys_t zb;
2731 2731 zio_prop_t zp;
2732 2732 zio_t *zio;
2733 2733 int wp_flag = 0;
2734 2734
2735 2735 DB_DNODE_ENTER(db);
2736 2736 dn = DB_DNODE(db);
2737 2737 os = dn->dn_objset;
2738 2738
2739 2739 if (db->db_state != DB_NOFILL) {
2740 2740 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2741 2741 /*
2742 2742 * Private object buffers are released here rather
2743 2743 * than in dbuf_dirty() since they are only modified
2744 2744 * in the syncing context and we don't want the
2745 2745 * overhead of making multiple copies of the data.
2746 2746 */
2747 2747 if (BP_IS_HOLE(db->db_blkptr)) {
2748 2748 arc_buf_thaw(data);
2749 2749 } else {
2750 2750 dbuf_release_bp(db);
2751 2751 }
2752 2752 }
2753 2753 }
2754 2754
2755 2755 if (parent != dn->dn_dbuf) {
2756 2756 /* Our parent is an indirect block. */
2757 2757 /* We have a dirty parent that has been scheduled for write. */
2758 2758 ASSERT(parent && parent->db_data_pending);
2759 2759 /* Our parent's buffer is one level closer to the dnode. */
2760 2760 ASSERT(db->db_level == parent->db_level-1);
2761 2761 /*
2762 2762 * We're about to modify our parent's db_data by modifying
2763 2763 * our block pointer, so the parent must be released.
2764 2764 */
2765 2765 ASSERT(arc_released(parent->db_buf));
2766 2766 zio = parent->db_data_pending->dr_zio;
2767 2767 } else {
2768 2768 /* Our parent is the dnode itself. */
2769 2769 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2770 2770 db->db_blkid != DMU_SPILL_BLKID) ||
2771 2771 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2772 2772 if (db->db_blkid != DMU_SPILL_BLKID)
2773 2773 ASSERT3P(db->db_blkptr, ==,
2774 2774 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2775 2775 zio = dn->dn_zio;
2776 2776 }
2777 2777
2778 2778 ASSERT(db->db_level == 0 || data == db->db_buf);
2779 2779 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2780 2780 ASSERT(zio);
2781 2781
2782 2782 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2783 2783 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2784 2784 db->db.db_object, db->db_level, db->db_blkid);
2785 2785
2786 2786 if (db->db_blkid == DMU_SPILL_BLKID)
2787 2787 wp_flag = WP_SPILL;
2788 2788 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2789 2789
2790 2790 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2791 2791 DB_DNODE_EXIT(db);
2792 2792
2793 2793 if (db->db_level == 0 &&
2794 2794 dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2795 2795 /*
2796 2796 * The BP for this block has been provided by open context
2797 2797 * (by dmu_sync() or dmu_buf_write_embedded()).
2798 2798 */
2799 2799 void *contents = (data != NULL) ? data->b_data : NULL;
2800 2800
2801 2801 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2802 2802 db->db_blkptr, contents, db->db.db_size, &zp,
2803 2803 dbuf_write_override_ready, NULL, dbuf_write_override_done,
2804 2804 dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2805 2805 mutex_enter(&db->db_mtx);
2806 2806 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2807 2807 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2808 2808 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
2809 2809 mutex_exit(&db->db_mtx);
2810 2810 } else if (db->db_state == DB_NOFILL) {
2811 2811 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF ||
2812 2812 zp.zp_checksum == ZIO_CHECKSUM_NOPARITY);
2813 2813 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2814 2814 db->db_blkptr, NULL, db->db.db_size, &zp,
2815 2815 dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db,
2816 2816 ZIO_PRIORITY_ASYNC_WRITE,
2817 2817 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2818 2818 } else {
2819 2819 ASSERT(arc_released(data));
2820 2820 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2821 2821 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db),
2822 2822 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
2823 2823 dbuf_write_physdone, dbuf_write_done, db,
2824 2824 ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2825 2825 }
2826 2826 }
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