Print this page
4045 zfs write throttle & i/o scheduler performance work
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
| Split |
Close |
| Expand all |
| Collapse all |
--- 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) 2013 by Delphix. All rights reserved.
25 25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26 26 */
27 27
28 28 #include <sys/zfs_context.h>
29 29 #include <sys/dmu.h>
30 30 #include <sys/dmu_send.h>
31 31 #include <sys/dmu_impl.h>
32 32 #include <sys/dbuf.h>
33 33 #include <sys/dmu_objset.h>
34 34 #include <sys/dsl_dataset.h>
35 35 #include <sys/dsl_dir.h>
36 36 #include <sys/dmu_tx.h>
37 37 #include <sys/spa.h>
38 38 #include <sys/zio.h>
39 39 #include <sys/dmu_zfetch.h>
40 40 #include <sys/sa.h>
41 41 #include <sys/sa_impl.h>
42 42
43 43 /*
44 44 * Number of times that zfs_free_range() took the slow path while doing
45 45 * a zfs receive. A nonzero value indicates a potential performance problem.
46 46 */
47 47 uint64_t zfs_free_range_recv_miss;
48 48
49 49 static void dbuf_destroy(dmu_buf_impl_t *db);
50 50 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
51 51 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
52 52
53 53 /*
54 54 * Global data structures and functions for the dbuf cache.
55 55 */
56 56 static kmem_cache_t *dbuf_cache;
57 57
58 58 /* ARGSUSED */
59 59 static int
60 60 dbuf_cons(void *vdb, void *unused, int kmflag)
61 61 {
62 62 dmu_buf_impl_t *db = vdb;
63 63 bzero(db, sizeof (dmu_buf_impl_t));
64 64
65 65 mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL);
66 66 cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
67 67 refcount_create(&db->db_holds);
68 68 return (0);
69 69 }
70 70
71 71 /* ARGSUSED */
72 72 static void
73 73 dbuf_dest(void *vdb, void *unused)
74 74 {
75 75 dmu_buf_impl_t *db = vdb;
76 76 mutex_destroy(&db->db_mtx);
77 77 cv_destroy(&db->db_changed);
78 78 refcount_destroy(&db->db_holds);
79 79 }
80 80
81 81 /*
82 82 * dbuf hash table routines
83 83 */
84 84 static dbuf_hash_table_t dbuf_hash_table;
85 85
86 86 static uint64_t dbuf_hash_count;
87 87
88 88 static uint64_t
89 89 dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
90 90 {
91 91 uintptr_t osv = (uintptr_t)os;
92 92 uint64_t crc = -1ULL;
93 93
94 94 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
95 95 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
96 96 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
97 97 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
98 98 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
99 99 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
100 100 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
101 101
102 102 crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
103 103
104 104 return (crc);
105 105 }
106 106
107 107 #define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
108 108
109 109 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
110 110 ((dbuf)->db.db_object == (obj) && \
111 111 (dbuf)->db_objset == (os) && \
112 112 (dbuf)->db_level == (level) && \
113 113 (dbuf)->db_blkid == (blkid))
114 114
115 115 dmu_buf_impl_t *
116 116 dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
117 117 {
118 118 dbuf_hash_table_t *h = &dbuf_hash_table;
119 119 objset_t *os = dn->dn_objset;
120 120 uint64_t obj = dn->dn_object;
121 121 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
122 122 uint64_t idx = hv & h->hash_table_mask;
123 123 dmu_buf_impl_t *db;
124 124
125 125 mutex_enter(DBUF_HASH_MUTEX(h, idx));
126 126 for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
127 127 if (DBUF_EQUAL(db, os, obj, level, blkid)) {
128 128 mutex_enter(&db->db_mtx);
129 129 if (db->db_state != DB_EVICTING) {
130 130 mutex_exit(DBUF_HASH_MUTEX(h, idx));
131 131 return (db);
132 132 }
133 133 mutex_exit(&db->db_mtx);
134 134 }
135 135 }
136 136 mutex_exit(DBUF_HASH_MUTEX(h, idx));
137 137 return (NULL);
138 138 }
139 139
140 140 /*
141 141 * Insert an entry into the hash table. If there is already an element
142 142 * equal to elem in the hash table, then the already existing element
143 143 * will be returned and the new element will not be inserted.
144 144 * Otherwise returns NULL.
145 145 */
146 146 static dmu_buf_impl_t *
147 147 dbuf_hash_insert(dmu_buf_impl_t *db)
148 148 {
149 149 dbuf_hash_table_t *h = &dbuf_hash_table;
150 150 objset_t *os = db->db_objset;
151 151 uint64_t obj = db->db.db_object;
152 152 int level = db->db_level;
153 153 uint64_t blkid = db->db_blkid;
154 154 uint64_t hv = DBUF_HASH(os, obj, level, blkid);
155 155 uint64_t idx = hv & h->hash_table_mask;
156 156 dmu_buf_impl_t *dbf;
157 157
158 158 mutex_enter(DBUF_HASH_MUTEX(h, idx));
159 159 for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
160 160 if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
161 161 mutex_enter(&dbf->db_mtx);
162 162 if (dbf->db_state != DB_EVICTING) {
163 163 mutex_exit(DBUF_HASH_MUTEX(h, idx));
164 164 return (dbf);
165 165 }
166 166 mutex_exit(&dbf->db_mtx);
167 167 }
168 168 }
169 169
170 170 mutex_enter(&db->db_mtx);
171 171 db->db_hash_next = h->hash_table[idx];
172 172 h->hash_table[idx] = db;
173 173 mutex_exit(DBUF_HASH_MUTEX(h, idx));
174 174 atomic_add_64(&dbuf_hash_count, 1);
175 175
176 176 return (NULL);
177 177 }
178 178
179 179 /*
180 180 * Remove an entry from the hash table. This operation will
181 181 * fail if there are any existing holds on the db.
182 182 */
183 183 static void
184 184 dbuf_hash_remove(dmu_buf_impl_t *db)
185 185 {
186 186 dbuf_hash_table_t *h = &dbuf_hash_table;
187 187 uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
188 188 db->db_level, db->db_blkid);
189 189 uint64_t idx = hv & h->hash_table_mask;
190 190 dmu_buf_impl_t *dbf, **dbp;
191 191
192 192 /*
193 193 * We musn't hold db_mtx to maintin lock ordering:
194 194 * DBUF_HASH_MUTEX > db_mtx.
195 195 */
196 196 ASSERT(refcount_is_zero(&db->db_holds));
197 197 ASSERT(db->db_state == DB_EVICTING);
198 198 ASSERT(!MUTEX_HELD(&db->db_mtx));
199 199
200 200 mutex_enter(DBUF_HASH_MUTEX(h, idx));
201 201 dbp = &h->hash_table[idx];
202 202 while ((dbf = *dbp) != db) {
203 203 dbp = &dbf->db_hash_next;
204 204 ASSERT(dbf != NULL);
205 205 }
206 206 *dbp = db->db_hash_next;
207 207 db->db_hash_next = NULL;
208 208 mutex_exit(DBUF_HASH_MUTEX(h, idx));
209 209 atomic_add_64(&dbuf_hash_count, -1);
210 210 }
211 211
212 212 static arc_evict_func_t dbuf_do_evict;
213 213
214 214 static void
215 215 dbuf_evict_user(dmu_buf_impl_t *db)
216 216 {
217 217 ASSERT(MUTEX_HELD(&db->db_mtx));
218 218
219 219 if (db->db_level != 0 || db->db_evict_func == NULL)
220 220 return;
221 221
222 222 if (db->db_user_data_ptr_ptr)
223 223 *db->db_user_data_ptr_ptr = db->db.db_data;
224 224 db->db_evict_func(&db->db, db->db_user_ptr);
225 225 db->db_user_ptr = NULL;
226 226 db->db_user_data_ptr_ptr = NULL;
227 227 db->db_evict_func = NULL;
228 228 }
229 229
230 230 boolean_t
231 231 dbuf_is_metadata(dmu_buf_impl_t *db)
232 232 {
233 233 if (db->db_level > 0) {
234 234 return (B_TRUE);
235 235 } else {
236 236 boolean_t is_metadata;
237 237
238 238 DB_DNODE_ENTER(db);
239 239 is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type);
240 240 DB_DNODE_EXIT(db);
241 241
242 242 return (is_metadata);
243 243 }
244 244 }
245 245
246 246 void
247 247 dbuf_evict(dmu_buf_impl_t *db)
248 248 {
249 249 ASSERT(MUTEX_HELD(&db->db_mtx));
250 250 ASSERT(db->db_buf == NULL);
251 251 ASSERT(db->db_data_pending == NULL);
252 252
253 253 dbuf_clear(db);
254 254 dbuf_destroy(db);
255 255 }
256 256
257 257 void
258 258 dbuf_init(void)
259 259 {
260 260 uint64_t hsize = 1ULL << 16;
261 261 dbuf_hash_table_t *h = &dbuf_hash_table;
262 262 int i;
263 263
264 264 /*
265 265 * The hash table is big enough to fill all of physical memory
266 266 * with an average 4K block size. The table will take up
267 267 * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
268 268 */
269 269 while (hsize * 4096 < physmem * PAGESIZE)
270 270 hsize <<= 1;
271 271
272 272 retry:
273 273 h->hash_table_mask = hsize - 1;
274 274 h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
275 275 if (h->hash_table == NULL) {
276 276 /* XXX - we should really return an error instead of assert */
277 277 ASSERT(hsize > (1ULL << 10));
278 278 hsize >>= 1;
279 279 goto retry;
280 280 }
281 281
282 282 dbuf_cache = kmem_cache_create("dmu_buf_impl_t",
283 283 sizeof (dmu_buf_impl_t),
284 284 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0);
285 285
286 286 for (i = 0; i < DBUF_MUTEXES; i++)
287 287 mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL);
288 288 }
289 289
290 290 void
291 291 dbuf_fini(void)
292 292 {
293 293 dbuf_hash_table_t *h = &dbuf_hash_table;
294 294 int i;
295 295
296 296 for (i = 0; i < DBUF_MUTEXES; i++)
297 297 mutex_destroy(&h->hash_mutexes[i]);
298 298 kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
299 299 kmem_cache_destroy(dbuf_cache);
300 300 }
301 301
302 302 /*
303 303 * Other stuff.
304 304 */
305 305
306 306 #ifdef ZFS_DEBUG
307 307 static void
308 308 dbuf_verify(dmu_buf_impl_t *db)
309 309 {
310 310 dnode_t *dn;
311 311 dbuf_dirty_record_t *dr;
312 312
313 313 ASSERT(MUTEX_HELD(&db->db_mtx));
314 314
315 315 if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY))
316 316 return;
317 317
318 318 ASSERT(db->db_objset != NULL);
319 319 DB_DNODE_ENTER(db);
320 320 dn = DB_DNODE(db);
321 321 if (dn == NULL) {
322 322 ASSERT(db->db_parent == NULL);
323 323 ASSERT(db->db_blkptr == NULL);
324 324 } else {
325 325 ASSERT3U(db->db.db_object, ==, dn->dn_object);
326 326 ASSERT3P(db->db_objset, ==, dn->dn_objset);
327 327 ASSERT3U(db->db_level, <, dn->dn_nlevels);
328 328 ASSERT(db->db_blkid == DMU_BONUS_BLKID ||
329 329 db->db_blkid == DMU_SPILL_BLKID ||
330 330 !list_is_empty(&dn->dn_dbufs));
331 331 }
332 332 if (db->db_blkid == DMU_BONUS_BLKID) {
333 333 ASSERT(dn != NULL);
334 334 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
335 335 ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID);
336 336 } else if (db->db_blkid == DMU_SPILL_BLKID) {
337 337 ASSERT(dn != NULL);
338 338 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
339 339 ASSERT0(db->db.db_offset);
340 340 } else {
341 341 ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
342 342 }
343 343
344 344 for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
345 345 ASSERT(dr->dr_dbuf == db);
346 346
347 347 for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
348 348 ASSERT(dr->dr_dbuf == db);
349 349
350 350 /*
351 351 * We can't assert that db_size matches dn_datablksz because it
352 352 * can be momentarily different when another thread is doing
353 353 * dnode_set_blksz().
354 354 */
355 355 if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) {
356 356 dr = db->db_data_pending;
357 357 /*
358 358 * It should only be modified in syncing context, so
359 359 * make sure we only have one copy of the data.
360 360 */
361 361 ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf);
362 362 }
363 363
364 364 /* verify db->db_blkptr */
365 365 if (db->db_blkptr) {
366 366 if (db->db_parent == dn->dn_dbuf) {
367 367 /* db is pointed to by the dnode */
368 368 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
369 369 if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
370 370 ASSERT(db->db_parent == NULL);
371 371 else
372 372 ASSERT(db->db_parent != NULL);
373 373 if (db->db_blkid != DMU_SPILL_BLKID)
374 374 ASSERT3P(db->db_blkptr, ==,
375 375 &dn->dn_phys->dn_blkptr[db->db_blkid]);
376 376 } else {
377 377 /* db is pointed to by an indirect block */
378 378 int epb = db->db_parent->db.db_size >> SPA_BLKPTRSHIFT;
379 379 ASSERT3U(db->db_parent->db_level, ==, db->db_level+1);
380 380 ASSERT3U(db->db_parent->db.db_object, ==,
381 381 db->db.db_object);
382 382 /*
383 383 * dnode_grow_indblksz() can make this fail if we don't
384 384 * have the struct_rwlock. XXX indblksz no longer
385 385 * grows. safe to do this now?
386 386 */
387 387 if (RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
388 388 ASSERT3P(db->db_blkptr, ==,
389 389 ((blkptr_t *)db->db_parent->db.db_data +
390 390 db->db_blkid % epb));
391 391 }
392 392 }
393 393 }
394 394 if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) &&
395 395 (db->db_buf == NULL || db->db_buf->b_data) &&
396 396 db->db.db_data && db->db_blkid != DMU_BONUS_BLKID &&
397 397 db->db_state != DB_FILL && !dn->dn_free_txg) {
398 398 /*
399 399 * If the blkptr isn't set but they have nonzero data,
400 400 * it had better be dirty, otherwise we'll lose that
401 401 * data when we evict this buffer.
402 402 */
403 403 if (db->db_dirtycnt == 0) {
404 404 uint64_t *buf = db->db.db_data;
405 405 int i;
406 406
407 407 for (i = 0; i < db->db.db_size >> 3; i++) {
408 408 ASSERT(buf[i] == 0);
409 409 }
410 410 }
411 411 }
412 412 DB_DNODE_EXIT(db);
413 413 }
414 414 #endif
415 415
416 416 static void
417 417 dbuf_update_data(dmu_buf_impl_t *db)
418 418 {
419 419 ASSERT(MUTEX_HELD(&db->db_mtx));
420 420 if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
421 421 ASSERT(!refcount_is_zero(&db->db_holds));
422 422 *db->db_user_data_ptr_ptr = db->db.db_data;
423 423 }
424 424 }
425 425
426 426 static void
427 427 dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
428 428 {
429 429 ASSERT(MUTEX_HELD(&db->db_mtx));
430 430 ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
431 431 db->db_buf = buf;
432 432 if (buf != NULL) {
433 433 ASSERT(buf->b_data != NULL);
434 434 db->db.db_data = buf->b_data;
435 435 if (!arc_released(buf))
436 436 arc_set_callback(buf, dbuf_do_evict, db);
437 437 dbuf_update_data(db);
438 438 } else {
439 439 dbuf_evict_user(db);
440 440 db->db.db_data = NULL;
441 441 if (db->db_state != DB_NOFILL)
442 442 db->db_state = DB_UNCACHED;
443 443 }
444 444 }
445 445
446 446 /*
447 447 * Loan out an arc_buf for read. Return the loaned arc_buf.
448 448 */
449 449 arc_buf_t *
450 450 dbuf_loan_arcbuf(dmu_buf_impl_t *db)
451 451 {
452 452 arc_buf_t *abuf;
453 453
454 454 mutex_enter(&db->db_mtx);
455 455 if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
456 456 int blksz = db->db.db_size;
457 457 spa_t *spa;
458 458
459 459 mutex_exit(&db->db_mtx);
460 460 DB_GET_SPA(&spa, db);
461 461 abuf = arc_loan_buf(spa, blksz);
462 462 bcopy(db->db.db_data, abuf->b_data, blksz);
463 463 } else {
464 464 abuf = db->db_buf;
465 465 arc_loan_inuse_buf(abuf, db);
466 466 dbuf_set_data(db, NULL);
467 467 mutex_exit(&db->db_mtx);
468 468 }
469 469 return (abuf);
470 470 }
471 471
472 472 uint64_t
473 473 dbuf_whichblock(dnode_t *dn, uint64_t offset)
474 474 {
475 475 if (dn->dn_datablkshift) {
476 476 return (offset >> dn->dn_datablkshift);
477 477 } else {
478 478 ASSERT3U(offset, <, dn->dn_datablksz);
479 479 return (0);
480 480 }
481 481 }
482 482
483 483 static void
484 484 dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
485 485 {
486 486 dmu_buf_impl_t *db = vdb;
487 487
488 488 mutex_enter(&db->db_mtx);
489 489 ASSERT3U(db->db_state, ==, DB_READ);
490 490 /*
491 491 * All reads are synchronous, so we must have a hold on the dbuf
492 492 */
493 493 ASSERT(refcount_count(&db->db_holds) > 0);
494 494 ASSERT(db->db_buf == NULL);
495 495 ASSERT(db->db.db_data == NULL);
496 496 if (db->db_level == 0 && db->db_freed_in_flight) {
497 497 /* we were freed in flight; disregard any error */
498 498 arc_release(buf, db);
499 499 bzero(buf->b_data, db->db.db_size);
500 500 arc_buf_freeze(buf);
501 501 db->db_freed_in_flight = FALSE;
502 502 dbuf_set_data(db, buf);
503 503 db->db_state = DB_CACHED;
504 504 } else if (zio == NULL || zio->io_error == 0) {
505 505 dbuf_set_data(db, buf);
506 506 db->db_state = DB_CACHED;
507 507 } else {
508 508 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
509 509 ASSERT3P(db->db_buf, ==, NULL);
510 510 VERIFY(arc_buf_remove_ref(buf, db));
511 511 db->db_state = DB_UNCACHED;
512 512 }
513 513 cv_broadcast(&db->db_changed);
514 514 dbuf_rele_and_unlock(db, NULL);
515 515 }
516 516
517 517 static void
518 518 dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
519 519 {
520 520 dnode_t *dn;
521 521 spa_t *spa;
522 522 zbookmark_t zb;
523 523 uint32_t aflags = ARC_NOWAIT;
524 524
525 525 DB_DNODE_ENTER(db);
526 526 dn = DB_DNODE(db);
527 527 ASSERT(!refcount_is_zero(&db->db_holds));
528 528 /* We need the struct_rwlock to prevent db_blkptr from changing. */
529 529 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
530 530 ASSERT(MUTEX_HELD(&db->db_mtx));
531 531 ASSERT(db->db_state == DB_UNCACHED);
532 532 ASSERT(db->db_buf == NULL);
533 533
534 534 if (db->db_blkid == DMU_BONUS_BLKID) {
535 535 int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
536 536
537 537 ASSERT3U(bonuslen, <=, db->db.db_size);
538 538 db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
539 539 arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
540 540 if (bonuslen < DN_MAX_BONUSLEN)
541 541 bzero(db->db.db_data, DN_MAX_BONUSLEN);
542 542 if (bonuslen)
543 543 bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
544 544 DB_DNODE_EXIT(db);
545 545 dbuf_update_data(db);
546 546 db->db_state = DB_CACHED;
547 547 mutex_exit(&db->db_mtx);
548 548 return;
549 549 }
550 550
551 551 /*
552 552 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
553 553 * processes the delete record and clears the bp while we are waiting
554 554 * for the dn_mtx (resulting in a "no" from block_freed).
555 555 */
556 556 if (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
557 557 (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
558 558 BP_IS_HOLE(db->db_blkptr)))) {
559 559 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
560 560
561 561 dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
562 562 db->db.db_size, db, type));
563 563 DB_DNODE_EXIT(db);
564 564 bzero(db->db.db_data, db->db.db_size);
565 565 db->db_state = DB_CACHED;
566 566 *flags |= DB_RF_CACHED;
567 567 mutex_exit(&db->db_mtx);
568 568 return;
569 569 }
570 570
571 571 spa = dn->dn_objset->os_spa;
572 572 DB_DNODE_EXIT(db);
573 573
574 574 db->db_state = DB_READ;
575 575 mutex_exit(&db->db_mtx);
576 576
577 577 if (DBUF_IS_L2CACHEABLE(db))
578 578 aflags |= ARC_L2CACHE;
579 579 if (DBUF_IS_L2COMPRESSIBLE(db))
580 580 aflags |= ARC_L2COMPRESS;
581 581
582 582 SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
583 583 db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
584 584 db->db.db_object, db->db_level, db->db_blkid);
585 585
586 586 dbuf_add_ref(db, NULL);
587 587
588 588 (void) arc_read(zio, spa, db->db_blkptr,
589 589 dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
590 590 (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
591 591 &aflags, &zb);
592 592 if (aflags & ARC_CACHED)
593 593 *flags |= DB_RF_CACHED;
594 594 }
595 595
596 596 int
597 597 dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
598 598 {
599 599 int err = 0;
600 600 int havepzio = (zio != NULL);
601 601 int prefetch;
602 602 dnode_t *dn;
603 603
604 604 /*
605 605 * We don't have to hold the mutex to check db_state because it
606 606 * can't be freed while we have a hold on the buffer.
607 607 */
608 608 ASSERT(!refcount_is_zero(&db->db_holds));
609 609
610 610 if (db->db_state == DB_NOFILL)
611 611 return (SET_ERROR(EIO));
612 612
613 613 DB_DNODE_ENTER(db);
614 614 dn = DB_DNODE(db);
615 615 if ((flags & DB_RF_HAVESTRUCT) == 0)
616 616 rw_enter(&dn->dn_struct_rwlock, RW_READER);
617 617
618 618 prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
619 619 (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL &&
620 620 DBUF_IS_CACHEABLE(db);
621 621
622 622 mutex_enter(&db->db_mtx);
623 623 if (db->db_state == DB_CACHED) {
624 624 mutex_exit(&db->db_mtx);
625 625 if (prefetch)
626 626 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
627 627 db->db.db_size, TRUE);
628 628 if ((flags & DB_RF_HAVESTRUCT) == 0)
629 629 rw_exit(&dn->dn_struct_rwlock);
630 630 DB_DNODE_EXIT(db);
631 631 } else if (db->db_state == DB_UNCACHED) {
632 632 spa_t *spa = dn->dn_objset->os_spa;
633 633
634 634 if (zio == NULL)
635 635 zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
636 636 dbuf_read_impl(db, zio, &flags);
637 637
638 638 /* dbuf_read_impl has dropped db_mtx for us */
639 639
640 640 if (prefetch)
641 641 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
642 642 db->db.db_size, flags & DB_RF_CACHED);
643 643
644 644 if ((flags & DB_RF_HAVESTRUCT) == 0)
645 645 rw_exit(&dn->dn_struct_rwlock);
646 646 DB_DNODE_EXIT(db);
647 647
648 648 if (!havepzio)
649 649 err = zio_wait(zio);
650 650 } else {
651 651 /*
652 652 * Another reader came in while the dbuf was in flight
653 653 * between UNCACHED and CACHED. Either a writer will finish
654 654 * writing the buffer (sending the dbuf to CACHED) or the
655 655 * first reader's request will reach the read_done callback
656 656 * and send the dbuf to CACHED. Otherwise, a failure
657 657 * occurred and the dbuf went to UNCACHED.
658 658 */
659 659 mutex_exit(&db->db_mtx);
660 660 if (prefetch)
661 661 dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
662 662 db->db.db_size, TRUE);
663 663 if ((flags & DB_RF_HAVESTRUCT) == 0)
664 664 rw_exit(&dn->dn_struct_rwlock);
665 665 DB_DNODE_EXIT(db);
666 666
667 667 /* Skip the wait per the caller's request. */
668 668 mutex_enter(&db->db_mtx);
669 669 if ((flags & DB_RF_NEVERWAIT) == 0) {
670 670 while (db->db_state == DB_READ ||
671 671 db->db_state == DB_FILL) {
672 672 ASSERT(db->db_state == DB_READ ||
673 673 (flags & DB_RF_HAVESTRUCT) == 0);
674 674 cv_wait(&db->db_changed, &db->db_mtx);
675 675 }
676 676 if (db->db_state == DB_UNCACHED)
677 677 err = SET_ERROR(EIO);
678 678 }
679 679 mutex_exit(&db->db_mtx);
680 680 }
681 681
682 682 ASSERT(err || havepzio || db->db_state == DB_CACHED);
683 683 return (err);
684 684 }
685 685
686 686 static void
687 687 dbuf_noread(dmu_buf_impl_t *db)
688 688 {
689 689 ASSERT(!refcount_is_zero(&db->db_holds));
690 690 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
691 691 mutex_enter(&db->db_mtx);
692 692 while (db->db_state == DB_READ || db->db_state == DB_FILL)
693 693 cv_wait(&db->db_changed, &db->db_mtx);
694 694 if (db->db_state == DB_UNCACHED) {
695 695 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
696 696 spa_t *spa;
697 697
698 698 ASSERT(db->db_buf == NULL);
699 699 ASSERT(db->db.db_data == NULL);
700 700 DB_GET_SPA(&spa, db);
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;
756 756
757 757 DB_GET_SPA(&spa, db);
758 758 dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
759 759 bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
760 760 } else {
761 761 dbuf_set_data(db, NULL);
762 762 }
763 763 }
764 764
765 765 void
766 766 dbuf_unoverride(dbuf_dirty_record_t *dr)
767 767 {
768 768 dmu_buf_impl_t *db = dr->dr_dbuf;
769 769 blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
770 770 uint64_t txg = dr->dr_txg;
771 771
772 772 ASSERT(MUTEX_HELD(&db->db_mtx));
773 773 ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC);
774 774 ASSERT(db->db_level == 0);
775 775
776 776 if (db->db_blkid == DMU_BONUS_BLKID ||
777 777 dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN)
778 778 return;
779 779
780 780 ASSERT(db->db_data_pending != dr);
781 781
782 782 /* free this block */
783 783 if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) {
784 784 spa_t *spa;
785 785
786 786 DB_GET_SPA(&spa, db);
787 787 zio_free(spa, txg, bp);
788 788 }
789 789 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
790 790 dr->dt.dl.dr_nopwrite = B_FALSE;
791 791
792 792 /*
793 793 * Release the already-written buffer, so we leave it in
794 794 * a consistent dirty state. Note that all callers are
795 795 * modifying the buffer, so they will immediately do
796 796 * another (redundant) arc_release(). Therefore, leave
797 797 * the buf thawed to save the effort of freezing &
798 798 * immediately re-thawing it.
799 799 */
800 800 arc_release(dr->dt.dl.dr_data, db);
801 801 }
802 802
803 803 /*
804 804 * Evict (if its unreferenced) or clear (if its referenced) any level-0
805 805 * data blocks in the free range, so that any future readers will find
806 806 * empty blocks. Also, if we happen across any level-1 dbufs in the
807 807 * range that have not already been marked dirty, mark them dirty so
808 808 * they stay in memory.
809 809 *
810 810 * This is a no-op if the dataset is in the middle of an incremental
811 811 * receive; see comment below for details.
812 812 */
813 813 void
814 814 dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
815 815 {
816 816 dmu_buf_impl_t *db, *db_next;
817 817 uint64_t txg = tx->tx_txg;
818 818 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
819 819 uint64_t first_l1 = start >> epbs;
820 820 uint64_t last_l1 = end >> epbs;
821 821
822 822 if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) {
823 823 end = dn->dn_maxblkid;
824 824 last_l1 = end >> epbs;
825 825 }
826 826 dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
827 827
828 828 mutex_enter(&dn->dn_dbufs_mtx);
829 829 if (start >= dn->dn_unlisted_l0_blkid * dn->dn_datablksz) {
830 830 /* There can't be any dbufs in this range; no need to search. */
831 831 mutex_exit(&dn->dn_dbufs_mtx);
832 832 return;
833 833 } else if (dmu_objset_is_receiving(dn->dn_objset)) {
|
↓ open down ↓ |
833 lines elided |
↑ open up ↑ |
834 834 /*
835 835 * If we are receiving, we expect there to be no dbufs in
836 836 * the range to be freed, because receive modifies each
837 837 * block at most once, and in offset order. If this is
838 838 * not the case, it can lead to performance problems,
839 839 * so note that we unexpectedly took the slow path.
840 840 */
841 841 atomic_inc_64(&zfs_free_range_recv_miss);
842 842 }
843 843
844 - for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
844 + for (db = list_head(&dn->dn_dbufs); db != NULL; db = db_next) {
845 845 db_next = list_next(&dn->dn_dbufs, db);
846 846 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
847 847
848 848 if (db->db_level == 1 &&
849 849 db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
850 850 mutex_enter(&db->db_mtx);
851 851 if (db->db_last_dirty &&
852 852 db->db_last_dirty->dr_txg < txg) {
853 853 dbuf_add_ref(db, FTAG);
854 854 mutex_exit(&db->db_mtx);
855 855 dbuf_will_dirty(db, tx);
856 856 dbuf_rele(db, FTAG);
857 857 } else {
858 858 mutex_exit(&db->db_mtx);
859 859 }
860 860 }
861 861
862 862 if (db->db_level != 0)
863 863 continue;
864 864 dprintf_dbuf(db, "found buf %s\n", "");
865 865 if (db->db_blkid < start || db->db_blkid > end)
866 866 continue;
867 867
868 868 /* found a level 0 buffer in the range */
869 869 mutex_enter(&db->db_mtx);
870 870 if (dbuf_undirty(db, tx)) {
871 871 /* mutex has been dropped and dbuf destroyed */
872 872 continue;
873 873 }
874 874
875 875 if (db->db_state == DB_UNCACHED ||
876 876 db->db_state == DB_NOFILL ||
877 877 db->db_state == DB_EVICTING) {
878 878 ASSERT(db->db.db_data == NULL);
879 879 mutex_exit(&db->db_mtx);
880 880 continue;
881 881 }
882 882 if (db->db_state == DB_READ || db->db_state == DB_FILL) {
883 883 /* will be handled in dbuf_read_done or dbuf_rele */
884 884 db->db_freed_in_flight = TRUE;
885 885 mutex_exit(&db->db_mtx);
886 886 continue;
887 887 }
888 888 if (refcount_count(&db->db_holds) == 0) {
889 889 ASSERT(db->db_buf);
890 890 dbuf_clear(db);
891 891 continue;
892 892 }
893 893 /* The dbuf is referenced */
894 894
895 895 if (db->db_last_dirty != NULL) {
896 896 dbuf_dirty_record_t *dr = db->db_last_dirty;
897 897
898 898 if (dr->dr_txg == txg) {
899 899 /*
900 900 * This buffer is "in-use", re-adjust the file
901 901 * size to reflect that this buffer may
902 902 * contain new data when we sync.
903 903 */
904 904 if (db->db_blkid != DMU_SPILL_BLKID &&
905 905 db->db_blkid > dn->dn_maxblkid)
906 906 dn->dn_maxblkid = db->db_blkid;
907 907 dbuf_unoverride(dr);
908 908 } else {
909 909 /*
910 910 * This dbuf is not dirty in the open context.
911 911 * Either uncache it (if its not referenced in
912 912 * the open context) or reset its contents to
913 913 * empty.
914 914 */
915 915 dbuf_fix_old_data(db, txg);
916 916 }
917 917 }
918 918 /* clear the contents if its cached */
919 919 if (db->db_state == DB_CACHED) {
920 920 ASSERT(db->db.db_data != NULL);
921 921 arc_release(db->db_buf, db);
922 922 bzero(db->db.db_data, db->db.db_size);
923 923 arc_buf_freeze(db->db_buf);
924 924 }
925 925
926 926 mutex_exit(&db->db_mtx);
927 927 }
928 928 mutex_exit(&dn->dn_dbufs_mtx);
929 929 }
930 930
931 931 static int
932 932 dbuf_block_freeable(dmu_buf_impl_t *db)
933 933 {
934 934 dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
935 935 uint64_t birth_txg = 0;
936 936
937 937 /*
938 938 * We don't need any locking to protect db_blkptr:
939 939 * If it's syncing, then db_last_dirty will be set
940 940 * so we'll ignore db_blkptr.
941 941 */
942 942 ASSERT(MUTEX_HELD(&db->db_mtx));
943 943 if (db->db_last_dirty)
944 944 birth_txg = db->db_last_dirty->dr_txg;
945 945 else if (db->db_blkptr)
946 946 birth_txg = db->db_blkptr->blk_birth;
947 947
948 948 /*
949 949 * If we don't exist or are in a snapshot, we can't be freed.
950 950 * Don't pass the bp to dsl_dataset_block_freeable() since we
951 951 * are holding the db_mtx lock and might deadlock if we are
952 952 * prefetching a dedup-ed block.
953 953 */
954 954 if (birth_txg)
955 955 return (ds == NULL ||
956 956 dsl_dataset_block_freeable(ds, NULL, birth_txg));
957 957 else
958 958 return (FALSE);
959 959 }
960 960
961 961 void
962 962 dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
963 963 {
964 964 arc_buf_t *buf, *obuf;
965 965 int osize = db->db.db_size;
966 966 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
967 967 dnode_t *dn;
968 968
969 969 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
970 970
971 971 DB_DNODE_ENTER(db);
972 972 dn = DB_DNODE(db);
973 973
974 974 /* XXX does *this* func really need the lock? */
975 975 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
976 976
977 977 /*
978 978 * This call to dbuf_will_dirty() with the dn_struct_rwlock held
979 979 * is OK, because there can be no other references to the db
980 980 * when we are changing its size, so no concurrent DB_FILL can
981 981 * be happening.
982 982 */
983 983 /*
984 984 * XXX we should be doing a dbuf_read, checking the return
985 985 * value and returning that up to our callers
986 986 */
987 987 dbuf_will_dirty(db, tx);
988 988
989 989 /* create the data buffer for the new block */
990 990 buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
991 991
992 992 /* copy old block data to the new block */
993 993 obuf = db->db_buf;
994 994 bcopy(obuf->b_data, buf->b_data, MIN(osize, size));
995 995 /* zero the remainder */
996 996 if (size > osize)
997 997 bzero((uint8_t *)buf->b_data + osize, size - osize);
998 998
999 999 mutex_enter(&db->db_mtx);
1000 1000 dbuf_set_data(db, buf);
1001 1001 VERIFY(arc_buf_remove_ref(obuf, db));
1002 1002 db->db.db_size = size;
1003 1003
1004 1004 if (db->db_level == 0) {
1005 1005 ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
1006 1006 db->db_last_dirty->dt.dl.dr_data = buf;
1007 1007 }
1008 1008 mutex_exit(&db->db_mtx);
1009 1009
1010 1010 dnode_willuse_space(dn, size-osize, tx);
1011 1011 DB_DNODE_EXIT(db);
1012 1012 }
1013 1013
1014 1014 void
1015 1015 dbuf_release_bp(dmu_buf_impl_t *db)
1016 1016 {
1017 1017 objset_t *os;
1018 1018
1019 1019 DB_GET_OBJSET(&os, db);
1020 1020 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os)));
1021 1021 ASSERT(arc_released(os->os_phys_buf) ||
1022 1022 list_link_active(&os->os_dsl_dataset->ds_synced_link));
1023 1023 ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf));
1024 1024
1025 1025 (void) arc_release(db->db_buf, db);
1026 1026 }
1027 1027
1028 1028 dbuf_dirty_record_t *
1029 1029 dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1030 1030 {
1031 1031 dnode_t *dn;
1032 1032 objset_t *os;
1033 1033 dbuf_dirty_record_t **drp, *dr;
1034 1034 int drop_struct_lock = FALSE;
1035 1035 boolean_t do_free_accounting = B_FALSE;
1036 1036 int txgoff = tx->tx_txg & TXG_MASK;
1037 1037
1038 1038 ASSERT(tx->tx_txg != 0);
1039 1039 ASSERT(!refcount_is_zero(&db->db_holds));
1040 1040 DMU_TX_DIRTY_BUF(tx, db);
1041 1041
1042 1042 DB_DNODE_ENTER(db);
1043 1043 dn = DB_DNODE(db);
1044 1044 /*
1045 1045 * Shouldn't dirty a regular buffer in syncing context. Private
1046 1046 * objects may be dirtied in syncing context, but only if they
1047 1047 * were already pre-dirtied in open context.
1048 1048 */
1049 1049 ASSERT(!dmu_tx_is_syncing(tx) ||
1050 1050 BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
1051 1051 DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1052 1052 dn->dn_objset->os_dsl_dataset == NULL);
1053 1053 /*
1054 1054 * We make this assert for private objects as well, but after we
1055 1055 * check if we're already dirty. They are allowed to re-dirty
1056 1056 * in syncing context.
1057 1057 */
1058 1058 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1059 1059 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1060 1060 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1061 1061
1062 1062 mutex_enter(&db->db_mtx);
1063 1063 /*
1064 1064 * XXX make this true for indirects too? The problem is that
1065 1065 * transactions created with dmu_tx_create_assigned() from
1066 1066 * syncing context don't bother holding ahead.
1067 1067 */
1068 1068 ASSERT(db->db_level != 0 ||
1069 1069 db->db_state == DB_CACHED || db->db_state == DB_FILL ||
1070 1070 db->db_state == DB_NOFILL);
1071 1071
1072 1072 mutex_enter(&dn->dn_mtx);
1073 1073 /*
1074 1074 * Don't set dirtyctx to SYNC if we're just modifying this as we
1075 1075 * initialize the objset.
1076 1076 */
1077 1077 if (dn->dn_dirtyctx == DN_UNDIRTIED &&
1078 1078 !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
1079 1079 dn->dn_dirtyctx =
1080 1080 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
1081 1081 ASSERT(dn->dn_dirtyctx_firstset == NULL);
1082 1082 dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
1083 1083 }
1084 1084 mutex_exit(&dn->dn_mtx);
1085 1085
1086 1086 if (db->db_blkid == DMU_SPILL_BLKID)
1087 1087 dn->dn_have_spill = B_TRUE;
1088 1088
1089 1089 /*
1090 1090 * If this buffer is already dirty, we're done.
1091 1091 */
1092 1092 drp = &db->db_last_dirty;
1093 1093 ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
1094 1094 db->db.db_object == DMU_META_DNODE_OBJECT);
1095 1095 while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
1096 1096 drp = &dr->dr_next;
1097 1097 if (dr && dr->dr_txg == tx->tx_txg) {
1098 1098 DB_DNODE_EXIT(db);
1099 1099
1100 1100 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
1101 1101 /*
1102 1102 * If this buffer has already been written out,
1103 1103 * we now need to reset its state.
1104 1104 */
1105 1105 dbuf_unoverride(dr);
1106 1106 if (db->db.db_object != DMU_META_DNODE_OBJECT &&
1107 1107 db->db_state != DB_NOFILL)
1108 1108 arc_buf_thaw(db->db_buf);
1109 1109 }
1110 1110 mutex_exit(&db->db_mtx);
1111 1111 return (dr);
1112 1112 }
1113 1113
1114 1114 /*
1115 1115 * Only valid if not already dirty.
1116 1116 */
1117 1117 ASSERT(dn->dn_object == 0 ||
1118 1118 dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
1119 1119 (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
1120 1120
1121 1121 ASSERT3U(dn->dn_nlevels, >, db->db_level);
1122 1122 ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) ||
1123 1123 dn->dn_phys->dn_nlevels > db->db_level ||
1124 1124 dn->dn_next_nlevels[txgoff] > db->db_level ||
1125 1125 dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level ||
1126 1126 dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level);
1127 1127
1128 1128 /*
1129 1129 * We should only be dirtying in syncing context if it's the
1130 1130 * mos or we're initializing the os or it's a special object.
1131 1131 * However, we are allowed to dirty in syncing context provided
1132 1132 * we already dirtied it in open context. Hence we must make
1133 1133 * this assertion only if we're not already dirty.
1134 1134 */
1135 1135 os = dn->dn_objset;
1136 1136 ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
1137 1137 os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
1138 1138 ASSERT(db->db.db_size != 0);
1139 1139
1140 1140 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1141 1141
1142 1142 if (db->db_blkid != DMU_BONUS_BLKID) {
1143 1143 /*
1144 1144 * Update the accounting.
1145 1145 * Note: we delay "free accounting" until after we drop
1146 1146 * the db_mtx. This keeps us from grabbing other locks
1147 1147 * (and possibly deadlocking) in bp_get_dsize() while
1148 1148 * also holding the db_mtx.
1149 1149 */
1150 1150 dnode_willuse_space(dn, db->db.db_size, tx);
1151 1151 do_free_accounting = dbuf_block_freeable(db);
1152 1152 }
1153 1153
1154 1154 /*
1155 1155 * If this buffer is dirty in an old transaction group we need
1156 1156 * to make a copy of it so that the changes we make in this
1157 1157 * transaction group won't leak out when we sync the older txg.
1158 1158 */
1159 1159 dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP);
1160 1160 if (db->db_level == 0) {
1161 1161 void *data_old = db->db_buf;
1162 1162
1163 1163 if (db->db_state != DB_NOFILL) {
1164 1164 if (db->db_blkid == DMU_BONUS_BLKID) {
1165 1165 dbuf_fix_old_data(db, tx->tx_txg);
1166 1166 data_old = db->db.db_data;
1167 1167 } else if (db->db.db_object != DMU_META_DNODE_OBJECT) {
1168 1168 /*
1169 1169 * Release the data buffer from the cache so
1170 1170 * that we can modify it without impacting
1171 1171 * possible other users of this cached data
1172 1172 * block. Note that indirect blocks and
1173 1173 * private objects are not released until the
1174 1174 * syncing state (since they are only modified
1175 1175 * then).
1176 1176 */
1177 1177 arc_release(db->db_buf, db);
1178 1178 dbuf_fix_old_data(db, tx->tx_txg);
1179 1179 data_old = db->db_buf;
|
↓ open down ↓ |
325 lines elided |
↑ open up ↑ |
1180 1180 }
1181 1181 ASSERT(data_old != NULL);
1182 1182 }
1183 1183 dr->dt.dl.dr_data = data_old;
1184 1184 } else {
1185 1185 mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_DEFAULT, NULL);
1186 1186 list_create(&dr->dt.di.dr_children,
1187 1187 sizeof (dbuf_dirty_record_t),
1188 1188 offsetof(dbuf_dirty_record_t, dr_dirty_node));
1189 1189 }
1190 + if (db->db_blkid != DMU_BONUS_BLKID && os->os_dsl_dataset != NULL)
1191 + dr->dr_accounted = db->db.db_size;
1190 1192 dr->dr_dbuf = db;
1191 1193 dr->dr_txg = tx->tx_txg;
1192 1194 dr->dr_next = *drp;
1193 1195 *drp = dr;
1194 1196
1195 1197 /*
1196 1198 * We could have been freed_in_flight between the dbuf_noread
1197 1199 * and dbuf_dirty. We win, as though the dbuf_noread() had
1198 1200 * happened after the free.
1199 1201 */
1200 1202 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1201 1203 db->db_blkid != DMU_SPILL_BLKID) {
1202 1204 mutex_enter(&dn->dn_mtx);
1203 1205 dnode_clear_range(dn, db->db_blkid, 1, tx);
1204 1206 mutex_exit(&dn->dn_mtx);
1205 1207 db->db_freed_in_flight = FALSE;
1206 1208 }
1207 1209
1208 1210 /*
1209 1211 * This buffer is now part of this txg
1210 1212 */
1211 1213 dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg);
1212 1214 db->db_dirtycnt += 1;
1213 1215 ASSERT3U(db->db_dirtycnt, <=, 3);
1214 1216
1215 1217 mutex_exit(&db->db_mtx);
1216 1218
1217 1219 if (db->db_blkid == DMU_BONUS_BLKID ||
1218 1220 db->db_blkid == DMU_SPILL_BLKID) {
1219 1221 mutex_enter(&dn->dn_mtx);
1220 1222 ASSERT(!list_link_active(&dr->dr_dirty_node));
1221 1223 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1222 1224 mutex_exit(&dn->dn_mtx);
1223 1225 dnode_setdirty(dn, tx);
1224 1226 DB_DNODE_EXIT(db);
1225 1227 return (dr);
1226 1228 } else if (do_free_accounting) {
1227 1229 blkptr_t *bp = db->db_blkptr;
1228 1230 int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
1229 1231 bp_get_dsize(os->os_spa, bp) : db->db.db_size;
1230 1232 /*
1231 1233 * This is only a guess -- if the dbuf is dirty
1232 1234 * in a previous txg, we don't know how much
1233 1235 * space it will use on disk yet. We should
1234 1236 * really have the struct_rwlock to access
1235 1237 * db_blkptr, but since this is just a guess,
1236 1238 * it's OK if we get an odd answer.
1237 1239 */
1238 1240 ddt_prefetch(os->os_spa, bp);
1239 1241 dnode_willuse_space(dn, -willfree, tx);
1240 1242 }
1241 1243
1242 1244 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
1243 1245 rw_enter(&dn->dn_struct_rwlock, RW_READER);
1244 1246 drop_struct_lock = TRUE;
1245 1247 }
1246 1248
1247 1249 if (db->db_level == 0) {
1248 1250 dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
1249 1251 ASSERT(dn->dn_maxblkid >= db->db_blkid);
1250 1252 }
1251 1253
1252 1254 if (db->db_level+1 < dn->dn_nlevels) {
1253 1255 dmu_buf_impl_t *parent = db->db_parent;
1254 1256 dbuf_dirty_record_t *di;
1255 1257 int parent_held = FALSE;
1256 1258
1257 1259 if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) {
1258 1260 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1259 1261
1260 1262 parent = dbuf_hold_level(dn, db->db_level+1,
1261 1263 db->db_blkid >> epbs, FTAG);
1262 1264 ASSERT(parent != NULL);
|
↓ open down ↓ |
63 lines elided |
↑ open up ↑ |
1263 1265 parent_held = TRUE;
1264 1266 }
1265 1267 if (drop_struct_lock)
1266 1268 rw_exit(&dn->dn_struct_rwlock);
1267 1269 ASSERT3U(db->db_level+1, ==, parent->db_level);
1268 1270 di = dbuf_dirty(parent, tx);
1269 1271 if (parent_held)
1270 1272 dbuf_rele(parent, FTAG);
1271 1273
1272 1274 mutex_enter(&db->db_mtx);
1273 - /* possible race with dbuf_undirty() */
1275 + /*
1276 + * Since we've dropped the mutex, it's possible that
1277 + * dbuf_undirty() might have changed this out from under us.
1278 + */
1274 1279 if (db->db_last_dirty == dr ||
1275 1280 dn->dn_object == DMU_META_DNODE_OBJECT) {
1276 1281 mutex_enter(&di->dt.di.dr_mtx);
1277 1282 ASSERT3U(di->dr_txg, ==, tx->tx_txg);
1278 1283 ASSERT(!list_link_active(&dr->dr_dirty_node));
1279 1284 list_insert_tail(&di->dt.di.dr_children, dr);
1280 1285 mutex_exit(&di->dt.di.dr_mtx);
1281 1286 dr->dr_parent = di;
1282 1287 }
1283 1288 mutex_exit(&db->db_mtx);
1284 1289 } else {
1285 1290 ASSERT(db->db_level+1 == dn->dn_nlevels);
1286 1291 ASSERT(db->db_blkid < dn->dn_nblkptr);
1287 1292 ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf);
1288 1293 mutex_enter(&dn->dn_mtx);
1289 1294 ASSERT(!list_link_active(&dr->dr_dirty_node));
1290 1295 list_insert_tail(&dn->dn_dirty_records[txgoff], dr);
1291 1296 mutex_exit(&dn->dn_mtx);
1292 1297 if (drop_struct_lock)
1293 1298 rw_exit(&dn->dn_struct_rwlock);
1294 1299 }
1295 1300
1296 1301 dnode_setdirty(dn, tx);
1297 1302 DB_DNODE_EXIT(db);
1298 1303 return (dr);
1299 1304 }
1300 1305
1301 1306 /*
1302 1307 * Undirty a buffer in the transaction group referenced by the given
1303 1308 * transaction. Return whether this evicted the dbuf.
1304 1309 */
1305 1310 static boolean_t
1306 1311 dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1307 1312 {
1308 1313 dnode_t *dn;
1309 1314 uint64_t txg = tx->tx_txg;
1310 1315 dbuf_dirty_record_t *dr, **drp;
1311 1316
1312 1317 ASSERT(txg != 0);
1313 1318 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1314 1319 ASSERT0(db->db_level);
1315 1320 ASSERT(MUTEX_HELD(&db->db_mtx));
1316 1321
1317 1322 /*
1318 1323 * If this buffer is not dirty, we're done.
1319 1324 */
1320 1325 for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1321 1326 if (dr->dr_txg <= txg)
1322 1327 break;
1323 1328 if (dr == NULL || dr->dr_txg < txg)
1324 1329 return (B_FALSE);
1325 1330 ASSERT(dr->dr_txg == txg);
1326 1331 ASSERT(dr->dr_dbuf == db);
1327 1332
1328 1333 DB_DNODE_ENTER(db);
1329 1334 dn = DB_DNODE(db);
1330 1335
1331 1336 /*
1332 1337 * Note: This code will probably work even if there are concurrent
|
↓ open down ↓ |
49 lines elided |
↑ open up ↑ |
1333 1338 * holders, but it is untested in that scenerio, as the ZPL and
1334 1339 * ztest have additional locking (the range locks) that prevents
1335 1340 * that type of concurrent access.
1336 1341 */
1337 1342 ASSERT3U(refcount_count(&db->db_holds), ==, db->db_dirtycnt);
1338 1343
1339 1344 dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
1340 1345
1341 1346 ASSERT(db->db.db_size != 0);
1342 1347
1343 - /* XXX would be nice to fix up dn_towrite_space[] */
1348 + /*
1349 + * Any space we accounted for in dp_dirty_* will be cleaned up by
1350 + * dsl_pool_sync(). This is relatively rare so the discrepancy
1351 + * is not a big deal.
1352 + */
1344 1353
1345 1354 *drp = dr->dr_next;
1346 1355
1347 1356 /*
1348 1357 * Note that there are three places in dbuf_dirty()
1349 1358 * where this dirty record may be put on a list.
1350 1359 * Make sure to do a list_remove corresponding to
1351 1360 * every one of those list_insert calls.
1352 1361 */
1353 1362 if (dr->dr_parent) {
1354 1363 mutex_enter(&dr->dr_parent->dt.di.dr_mtx);
1355 1364 list_remove(&dr->dr_parent->dt.di.dr_children, dr);
1356 1365 mutex_exit(&dr->dr_parent->dt.di.dr_mtx);
1357 1366 } else if (db->db_blkid == DMU_SPILL_BLKID ||
1358 1367 db->db_level+1 == dn->dn_nlevels) {
1359 1368 ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf);
1360 1369 mutex_enter(&dn->dn_mtx);
1361 1370 list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr);
1362 1371 mutex_exit(&dn->dn_mtx);
1363 1372 }
1364 1373 DB_DNODE_EXIT(db);
1365 1374
1366 1375 if (db->db_state != DB_NOFILL) {
1367 1376 dbuf_unoverride(dr);
1368 1377
1369 1378 ASSERT(db->db_buf != NULL);
1370 1379 ASSERT(dr->dt.dl.dr_data != NULL);
1371 1380 if (dr->dt.dl.dr_data != db->db_buf)
1372 1381 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
1373 1382 }
1374 1383 kmem_free(dr, sizeof (dbuf_dirty_record_t));
1375 1384
1376 1385 ASSERT(db->db_dirtycnt > 0);
1377 1386 db->db_dirtycnt -= 1;
1378 1387
1379 1388 if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
1380 1389 arc_buf_t *buf = db->db_buf;
1381 1390
1382 1391 ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
1383 1392 dbuf_set_data(db, NULL);
1384 1393 VERIFY(arc_buf_remove_ref(buf, db));
1385 1394 dbuf_evict(db);
1386 1395 return (B_TRUE);
1387 1396 }
1388 1397
1389 1398 return (B_FALSE);
1390 1399 }
1391 1400
1392 1401 #pragma weak dmu_buf_will_dirty = dbuf_will_dirty
1393 1402 void
1394 1403 dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
1395 1404 {
1396 1405 int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
1397 1406
1398 1407 ASSERT(tx->tx_txg != 0);
1399 1408 ASSERT(!refcount_is_zero(&db->db_holds));
1400 1409
1401 1410 DB_DNODE_ENTER(db);
1402 1411 if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
1403 1412 rf |= DB_RF_HAVESTRUCT;
1404 1413 DB_DNODE_EXIT(db);
1405 1414 (void) dbuf_read(db, NULL, rf);
1406 1415 (void) dbuf_dirty(db, tx);
1407 1416 }
1408 1417
1409 1418 void
1410 1419 dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1411 1420 {
1412 1421 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1413 1422
1414 1423 db->db_state = DB_NOFILL;
1415 1424
1416 1425 dmu_buf_will_fill(db_fake, tx);
1417 1426 }
1418 1427
1419 1428 void
1420 1429 dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
1421 1430 {
1422 1431 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1423 1432
1424 1433 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1425 1434 ASSERT(tx->tx_txg != 0);
1426 1435 ASSERT(db->db_level == 0);
1427 1436 ASSERT(!refcount_is_zero(&db->db_holds));
1428 1437
1429 1438 ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT ||
1430 1439 dmu_tx_private_ok(tx));
1431 1440
1432 1441 dbuf_noread(db);
1433 1442 (void) dbuf_dirty(db, tx);
1434 1443 }
1435 1444
1436 1445 #pragma weak dmu_buf_fill_done = dbuf_fill_done
1437 1446 /* ARGSUSED */
1438 1447 void
1439 1448 dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
1440 1449 {
1441 1450 mutex_enter(&db->db_mtx);
1442 1451 DBUF_VERIFY(db);
1443 1452
1444 1453 if (db->db_state == DB_FILL) {
1445 1454 if (db->db_level == 0 && db->db_freed_in_flight) {
1446 1455 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1447 1456 /* we were freed while filling */
1448 1457 /* XXX dbuf_undirty? */
1449 1458 bzero(db->db.db_data, db->db.db_size);
1450 1459 db->db_freed_in_flight = FALSE;
1451 1460 }
1452 1461 db->db_state = DB_CACHED;
1453 1462 cv_broadcast(&db->db_changed);
1454 1463 }
1455 1464 mutex_exit(&db->db_mtx);
1456 1465 }
1457 1466
1458 1467 /*
1459 1468 * Directly assign a provided arc buf to a given dbuf if it's not referenced
1460 1469 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
1461 1470 */
1462 1471 void
1463 1472 dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
1464 1473 {
1465 1474 ASSERT(!refcount_is_zero(&db->db_holds));
1466 1475 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
1467 1476 ASSERT(db->db_level == 0);
1468 1477 ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
1469 1478 ASSERT(buf != NULL);
1470 1479 ASSERT(arc_buf_size(buf) == db->db.db_size);
1471 1480 ASSERT(tx->tx_txg != 0);
1472 1481
1473 1482 arc_return_buf(buf, db);
1474 1483 ASSERT(arc_released(buf));
1475 1484
1476 1485 mutex_enter(&db->db_mtx);
1477 1486
1478 1487 while (db->db_state == DB_READ || db->db_state == DB_FILL)
1479 1488 cv_wait(&db->db_changed, &db->db_mtx);
1480 1489
1481 1490 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
1482 1491
1483 1492 if (db->db_state == DB_CACHED &&
1484 1493 refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
1485 1494 mutex_exit(&db->db_mtx);
1486 1495 (void) dbuf_dirty(db, tx);
1487 1496 bcopy(buf->b_data, db->db.db_data, db->db.db_size);
1488 1497 VERIFY(arc_buf_remove_ref(buf, db));
1489 1498 xuio_stat_wbuf_copied();
1490 1499 return;
1491 1500 }
1492 1501
1493 1502 xuio_stat_wbuf_nocopy();
1494 1503 if (db->db_state == DB_CACHED) {
1495 1504 dbuf_dirty_record_t *dr = db->db_last_dirty;
1496 1505
1497 1506 ASSERT(db->db_buf != NULL);
1498 1507 if (dr != NULL && dr->dr_txg == tx->tx_txg) {
1499 1508 ASSERT(dr->dt.dl.dr_data == db->db_buf);
1500 1509 if (!arc_released(db->db_buf)) {
1501 1510 ASSERT(dr->dt.dl.dr_override_state ==
1502 1511 DR_OVERRIDDEN);
1503 1512 arc_release(db->db_buf, db);
1504 1513 }
1505 1514 dr->dt.dl.dr_data = buf;
1506 1515 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1507 1516 } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
1508 1517 arc_release(db->db_buf, db);
1509 1518 VERIFY(arc_buf_remove_ref(db->db_buf, db));
1510 1519 }
1511 1520 db->db_buf = NULL;
1512 1521 }
|
↓ open down ↓ |
159 lines elided |
↑ open up ↑ |
1513 1522 ASSERT(db->db_buf == NULL);
1514 1523 dbuf_set_data(db, buf);
1515 1524 db->db_state = DB_FILL;
1516 1525 mutex_exit(&db->db_mtx);
1517 1526 (void) dbuf_dirty(db, tx);
1518 1527 dbuf_fill_done(db, tx);
1519 1528 }
1520 1529
1521 1530 /*
1522 1531 * "Clear" the contents of this dbuf. This will mark the dbuf
1523 - * EVICTING and clear *most* of its references. Unfortunetely,
1532 + * EVICTING and clear *most* of its references. Unfortunately,
1524 1533 * when we are not holding the dn_dbufs_mtx, we can't clear the
1525 1534 * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
1526 1535 * in this case. For callers from the DMU we will usually see:
1527 1536 * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
1528 1537 * For the arc callback, we will usually see:
1529 1538 * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
1530 1539 * Sometimes, though, we will get a mix of these two:
1531 1540 * DMU: dbuf_clear()->arc_buf_evict()
1532 1541 * ARC: dbuf_do_evict()->dbuf_destroy()
1533 1542 */
1534 1543 void
1535 1544 dbuf_clear(dmu_buf_impl_t *db)
1536 1545 {
1537 1546 dnode_t *dn;
1538 1547 dmu_buf_impl_t *parent = db->db_parent;
1539 1548 dmu_buf_impl_t *dndb;
1540 1549 int dbuf_gone = FALSE;
1541 1550
1542 1551 ASSERT(MUTEX_HELD(&db->db_mtx));
1543 1552 ASSERT(refcount_is_zero(&db->db_holds));
1544 1553
1545 1554 dbuf_evict_user(db);
1546 1555
1547 1556 if (db->db_state == DB_CACHED) {
1548 1557 ASSERT(db->db.db_data != NULL);
1549 1558 if (db->db_blkid == DMU_BONUS_BLKID) {
1550 1559 zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
1551 1560 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
1552 1561 }
1553 1562 db->db.db_data = NULL;
1554 1563 db->db_state = DB_UNCACHED;
1555 1564 }
1556 1565
1557 1566 ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
1558 1567 ASSERT(db->db_data_pending == NULL);
1559 1568
1560 1569 db->db_state = DB_EVICTING;
1561 1570 db->db_blkptr = NULL;
1562 1571
1563 1572 DB_DNODE_ENTER(db);
1564 1573 dn = DB_DNODE(db);
1565 1574 dndb = dn->dn_dbuf;
1566 1575 if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
1567 1576 list_remove(&dn->dn_dbufs, db);
1568 1577 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1569 1578 membar_producer();
1570 1579 DB_DNODE_EXIT(db);
1571 1580 /*
1572 1581 * Decrementing the dbuf count means that the hold corresponding
1573 1582 * to the removed dbuf is no longer discounted in dnode_move(),
1574 1583 * so the dnode cannot be moved until after we release the hold.
1575 1584 * The membar_producer() ensures visibility of the decremented
1576 1585 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
1577 1586 * release any lock.
1578 1587 */
1579 1588 dnode_rele(dn, db);
1580 1589 db->db_dnode_handle = NULL;
1581 1590 } else {
1582 1591 DB_DNODE_EXIT(db);
1583 1592 }
1584 1593
1585 1594 if (db->db_buf)
1586 1595 dbuf_gone = arc_buf_evict(db->db_buf);
1587 1596
1588 1597 if (!dbuf_gone)
1589 1598 mutex_exit(&db->db_mtx);
1590 1599
1591 1600 /*
1592 1601 * If this dbuf is referenced from an indirect dbuf,
1593 1602 * decrement the ref count on the indirect dbuf.
1594 1603 */
1595 1604 if (parent && parent != dndb)
1596 1605 dbuf_rele(parent, db);
1597 1606 }
1598 1607
1599 1608 static int
1600 1609 dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
1601 1610 dmu_buf_impl_t **parentp, blkptr_t **bpp)
1602 1611 {
1603 1612 int nlevels, epbs;
1604 1613
1605 1614 *parentp = NULL;
1606 1615 *bpp = NULL;
1607 1616
1608 1617 ASSERT(blkid != DMU_BONUS_BLKID);
1609 1618
1610 1619 if (blkid == DMU_SPILL_BLKID) {
1611 1620 mutex_enter(&dn->dn_mtx);
1612 1621 if (dn->dn_have_spill &&
1613 1622 (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1614 1623 *bpp = &dn->dn_phys->dn_spill;
1615 1624 else
1616 1625 *bpp = NULL;
1617 1626 dbuf_add_ref(dn->dn_dbuf, NULL);
1618 1627 *parentp = dn->dn_dbuf;
1619 1628 mutex_exit(&dn->dn_mtx);
1620 1629 return (0);
1621 1630 }
1622 1631
1623 1632 if (dn->dn_phys->dn_nlevels == 0)
1624 1633 nlevels = 1;
1625 1634 else
1626 1635 nlevels = dn->dn_phys->dn_nlevels;
1627 1636
1628 1637 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1629 1638
1630 1639 ASSERT3U(level * epbs, <, 64);
1631 1640 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1632 1641 if (level >= nlevels ||
1633 1642 (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
1634 1643 /* the buffer has no parent yet */
1635 1644 return (SET_ERROR(ENOENT));
1636 1645 } else if (level < nlevels-1) {
1637 1646 /* this block is referenced from an indirect block */
1638 1647 int err = dbuf_hold_impl(dn, level+1,
1639 1648 blkid >> epbs, fail_sparse, NULL, parentp);
1640 1649 if (err)
1641 1650 return (err);
1642 1651 err = dbuf_read(*parentp, NULL,
1643 1652 (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL));
1644 1653 if (err) {
1645 1654 dbuf_rele(*parentp, NULL);
1646 1655 *parentp = NULL;
1647 1656 return (err);
1648 1657 }
1649 1658 *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
1650 1659 (blkid & ((1ULL << epbs) - 1));
1651 1660 return (0);
1652 1661 } else {
1653 1662 /* the block is referenced from the dnode */
1654 1663 ASSERT3U(level, ==, nlevels-1);
1655 1664 ASSERT(dn->dn_phys->dn_nblkptr == 0 ||
1656 1665 blkid < dn->dn_phys->dn_nblkptr);
1657 1666 if (dn->dn_dbuf) {
1658 1667 dbuf_add_ref(dn->dn_dbuf, NULL);
1659 1668 *parentp = dn->dn_dbuf;
1660 1669 }
1661 1670 *bpp = &dn->dn_phys->dn_blkptr[blkid];
1662 1671 return (0);
1663 1672 }
1664 1673 }
1665 1674
1666 1675 static dmu_buf_impl_t *
1667 1676 dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid,
1668 1677 dmu_buf_impl_t *parent, blkptr_t *blkptr)
1669 1678 {
1670 1679 objset_t *os = dn->dn_objset;
1671 1680 dmu_buf_impl_t *db, *odb;
1672 1681
1673 1682 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1674 1683 ASSERT(dn->dn_type != DMU_OT_NONE);
1675 1684
1676 1685 db = kmem_cache_alloc(dbuf_cache, KM_SLEEP);
1677 1686
1678 1687 db->db_objset = os;
1679 1688 db->db.db_object = dn->dn_object;
1680 1689 db->db_level = level;
1681 1690 db->db_blkid = blkid;
1682 1691 db->db_last_dirty = NULL;
1683 1692 db->db_dirtycnt = 0;
1684 1693 db->db_dnode_handle = dn->dn_handle;
1685 1694 db->db_parent = parent;
1686 1695 db->db_blkptr = blkptr;
1687 1696
1688 1697 db->db_user_ptr = NULL;
1689 1698 db->db_user_data_ptr_ptr = NULL;
1690 1699 db->db_evict_func = NULL;
1691 1700 db->db_immediate_evict = 0;
1692 1701 db->db_freed_in_flight = 0;
1693 1702
1694 1703 if (blkid == DMU_BONUS_BLKID) {
1695 1704 ASSERT3P(parent, ==, dn->dn_dbuf);
1696 1705 db->db.db_size = DN_MAX_BONUSLEN -
1697 1706 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
1698 1707 ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
1699 1708 db->db.db_offset = DMU_BONUS_BLKID;
|
↓ open down ↓ |
166 lines elided |
↑ open up ↑ |
1700 1709 db->db_state = DB_UNCACHED;
1701 1710 /* the bonus dbuf is not placed in the hash table */
1702 1711 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1703 1712 return (db);
1704 1713 } else if (blkid == DMU_SPILL_BLKID) {
1705 1714 db->db.db_size = (blkptr != NULL) ?
1706 1715 BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE;
1707 1716 db->db.db_offset = 0;
1708 1717 } else {
1709 1718 int blocksize =
1710 - db->db_level ? 1<<dn->dn_indblkshift : dn->dn_datablksz;
1719 + db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz;
1711 1720 db->db.db_size = blocksize;
1712 1721 db->db.db_offset = db->db_blkid * blocksize;
1713 1722 }
1714 1723
1715 1724 /*
1716 1725 * Hold the dn_dbufs_mtx while we get the new dbuf
1717 1726 * in the hash table *and* added to the dbufs list.
1718 1727 * This prevents a possible deadlock with someone
1719 1728 * trying to look up this dbuf before its added to the
1720 1729 * dn_dbufs list.
1721 1730 */
1722 1731 mutex_enter(&dn->dn_dbufs_mtx);
1723 1732 db->db_state = DB_EVICTING;
1724 1733 if ((odb = dbuf_hash_insert(db)) != NULL) {
1725 1734 /* someone else inserted it first */
1726 1735 kmem_cache_free(dbuf_cache, db);
1727 1736 mutex_exit(&dn->dn_dbufs_mtx);
1728 1737 return (odb);
1729 1738 }
1730 1739 list_insert_head(&dn->dn_dbufs, db);
1731 1740 if (db->db_level == 0 && db->db_blkid >=
1732 1741 dn->dn_unlisted_l0_blkid)
1733 1742 dn->dn_unlisted_l0_blkid = db->db_blkid + 1;
1734 1743 db->db_state = DB_UNCACHED;
1735 1744 mutex_exit(&dn->dn_dbufs_mtx);
1736 1745 arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1737 1746
1738 1747 if (parent && parent != dn->dn_dbuf)
1739 1748 dbuf_add_ref(parent, db);
1740 1749
1741 1750 ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
1742 1751 refcount_count(&dn->dn_holds) > 0);
1743 1752 (void) refcount_add(&dn->dn_holds, db);
1744 1753 (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
1745 1754
1746 1755 dprintf_dbuf(db, "db=%p\n", db);
1747 1756
1748 1757 return (db);
1749 1758 }
1750 1759
1751 1760 static int
1752 1761 dbuf_do_evict(void *private)
1753 1762 {
1754 1763 arc_buf_t *buf = private;
1755 1764 dmu_buf_impl_t *db = buf->b_private;
1756 1765
1757 1766 if (!MUTEX_HELD(&db->db_mtx))
1758 1767 mutex_enter(&db->db_mtx);
1759 1768
1760 1769 ASSERT(refcount_is_zero(&db->db_holds));
1761 1770
1762 1771 if (db->db_state != DB_EVICTING) {
1763 1772 ASSERT(db->db_state == DB_CACHED);
1764 1773 DBUF_VERIFY(db);
1765 1774 db->db_buf = NULL;
1766 1775 dbuf_evict(db);
1767 1776 } else {
1768 1777 mutex_exit(&db->db_mtx);
1769 1778 dbuf_destroy(db);
1770 1779 }
1771 1780 return (0);
1772 1781 }
1773 1782
1774 1783 static void
1775 1784 dbuf_destroy(dmu_buf_impl_t *db)
1776 1785 {
1777 1786 ASSERT(refcount_is_zero(&db->db_holds));
1778 1787
1779 1788 if (db->db_blkid != DMU_BONUS_BLKID) {
1780 1789 /*
1781 1790 * If this dbuf is still on the dn_dbufs list,
1782 1791 * remove it from that list.
1783 1792 */
1784 1793 if (db->db_dnode_handle != NULL) {
1785 1794 dnode_t *dn;
1786 1795
1787 1796 DB_DNODE_ENTER(db);
1788 1797 dn = DB_DNODE(db);
1789 1798 mutex_enter(&dn->dn_dbufs_mtx);
1790 1799 list_remove(&dn->dn_dbufs, db);
1791 1800 (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
1792 1801 mutex_exit(&dn->dn_dbufs_mtx);
1793 1802 DB_DNODE_EXIT(db);
1794 1803 /*
1795 1804 * Decrementing the dbuf count means that the hold
1796 1805 * corresponding to the removed dbuf is no longer
1797 1806 * discounted in dnode_move(), so the dnode cannot be
1798 1807 * moved until after we release the hold.
1799 1808 */
1800 1809 dnode_rele(dn, db);
1801 1810 db->db_dnode_handle = NULL;
1802 1811 }
1803 1812 dbuf_hash_remove(db);
1804 1813 }
1805 1814 db->db_parent = NULL;
1806 1815 db->db_buf = NULL;
1807 1816
1808 1817 ASSERT(!list_link_active(&db->db_link));
|
↓ open down ↓ |
88 lines elided |
↑ open up ↑ |
1809 1818 ASSERT(db->db.db_data == NULL);
1810 1819 ASSERT(db->db_hash_next == NULL);
1811 1820 ASSERT(db->db_blkptr == NULL);
1812 1821 ASSERT(db->db_data_pending == NULL);
1813 1822
1814 1823 kmem_cache_free(dbuf_cache, db);
1815 1824 arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
1816 1825 }
1817 1826
1818 1827 void
1819 -dbuf_prefetch(dnode_t *dn, uint64_t blkid)
1828 +dbuf_prefetch(dnode_t *dn, uint64_t blkid, zio_priority_t prio)
1820 1829 {
1821 1830 dmu_buf_impl_t *db = NULL;
1822 1831 blkptr_t *bp = NULL;
1823 1832
1824 1833 ASSERT(blkid != DMU_BONUS_BLKID);
1825 1834 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1826 1835
1827 1836 if (dnode_block_freed(dn, blkid))
1828 1837 return;
1829 1838
1830 1839 /* dbuf_find() returns with db_mtx held */
1831 1840 if (db = dbuf_find(dn, 0, blkid)) {
1832 1841 /*
|
↓ open down ↓ |
3 lines elided |
↑ open up ↑ |
1833 1842 * This dbuf is already in the cache. We assume that
1834 1843 * it is already CACHED, or else about to be either
1835 1844 * read or filled.
1836 1845 */
1837 1846 mutex_exit(&db->db_mtx);
1838 1847 return;
1839 1848 }
1840 1849
1841 1850 if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
1842 1851 if (bp && !BP_IS_HOLE(bp)) {
1843 - int priority = dn->dn_type == DMU_OT_DDT_ZAP ?
1844 - ZIO_PRIORITY_DDT_PREFETCH : ZIO_PRIORITY_ASYNC_READ;
1845 1852 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
1846 1853 uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
1847 1854 zbookmark_t zb;
1848 1855
1849 1856 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1850 1857 dn->dn_object, 0, blkid);
1851 1858
1852 1859 (void) arc_read(NULL, dn->dn_objset->os_spa,
1853 - bp, NULL, NULL, priority,
1860 + bp, NULL, NULL, prio,
1854 1861 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
1855 1862 &aflags, &zb);
1856 1863 }
1857 1864 if (db)
1858 1865 dbuf_rele(db, NULL);
1859 1866 }
1860 1867 }
1861 1868
1862 1869 /*
1863 1870 * Returns with db_holds incremented, and db_mtx not held.
1864 1871 * Note: dn_struct_rwlock must be held.
1865 1872 */
1866 1873 int
1867 1874 dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
1868 1875 void *tag, dmu_buf_impl_t **dbp)
1869 1876 {
1870 1877 dmu_buf_impl_t *db, *parent = NULL;
1871 1878
1872 1879 ASSERT(blkid != DMU_BONUS_BLKID);
1873 1880 ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
1874 1881 ASSERT3U(dn->dn_nlevels, >, level);
1875 1882
1876 1883 *dbp = NULL;
1877 1884 top:
1878 1885 /* dbuf_find() returns with db_mtx held */
1879 1886 db = dbuf_find(dn, level, blkid);
1880 1887
1881 1888 if (db == NULL) {
1882 1889 blkptr_t *bp = NULL;
1883 1890 int err;
1884 1891
1885 1892 ASSERT3P(parent, ==, NULL);
1886 1893 err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
1887 1894 if (fail_sparse) {
1888 1895 if (err == 0 && bp && BP_IS_HOLE(bp))
1889 1896 err = SET_ERROR(ENOENT);
1890 1897 if (err) {
1891 1898 if (parent)
1892 1899 dbuf_rele(parent, NULL);
1893 1900 return (err);
1894 1901 }
1895 1902 }
1896 1903 if (err && err != ENOENT)
1897 1904 return (err);
1898 1905 db = dbuf_create(dn, level, blkid, parent, bp);
1899 1906 }
1900 1907
1901 1908 if (db->db_buf && refcount_is_zero(&db->db_holds)) {
1902 1909 arc_buf_add_ref(db->db_buf, db);
1903 1910 if (db->db_buf->b_data == NULL) {
1904 1911 dbuf_clear(db);
1905 1912 if (parent) {
1906 1913 dbuf_rele(parent, NULL);
1907 1914 parent = NULL;
1908 1915 }
1909 1916 goto top;
1910 1917 }
1911 1918 ASSERT3P(db->db.db_data, ==, db->db_buf->b_data);
1912 1919 }
1913 1920
1914 1921 ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf));
1915 1922
1916 1923 /*
1917 1924 * If this buffer is currently syncing out, and we are are
1918 1925 * still referencing it from db_data, we need to make a copy
1919 1926 * of it in case we decide we want to dirty it again in this txg.
1920 1927 */
1921 1928 if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID &&
1922 1929 dn->dn_object != DMU_META_DNODE_OBJECT &&
1923 1930 db->db_state == DB_CACHED && db->db_data_pending) {
1924 1931 dbuf_dirty_record_t *dr = db->db_data_pending;
1925 1932
1926 1933 if (dr->dt.dl.dr_data == db->db_buf) {
1927 1934 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
1928 1935
1929 1936 dbuf_set_data(db,
1930 1937 arc_buf_alloc(dn->dn_objset->os_spa,
1931 1938 db->db.db_size, db, type));
1932 1939 bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
1933 1940 db->db.db_size);
1934 1941 }
1935 1942 }
1936 1943
1937 1944 (void) refcount_add(&db->db_holds, tag);
1938 1945 dbuf_update_data(db);
1939 1946 DBUF_VERIFY(db);
1940 1947 mutex_exit(&db->db_mtx);
1941 1948
1942 1949 /* NOTE: we can't rele the parent until after we drop the db_mtx */
1943 1950 if (parent)
1944 1951 dbuf_rele(parent, NULL);
1945 1952
1946 1953 ASSERT3P(DB_DNODE(db), ==, dn);
1947 1954 ASSERT3U(db->db_blkid, ==, blkid);
1948 1955 ASSERT3U(db->db_level, ==, level);
1949 1956 *dbp = db;
1950 1957
1951 1958 return (0);
1952 1959 }
1953 1960
1954 1961 dmu_buf_impl_t *
1955 1962 dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag)
1956 1963 {
1957 1964 dmu_buf_impl_t *db;
1958 1965 int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
1959 1966 return (err ? NULL : db);
1960 1967 }
1961 1968
1962 1969 dmu_buf_impl_t *
1963 1970 dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag)
1964 1971 {
1965 1972 dmu_buf_impl_t *db;
1966 1973 int err = dbuf_hold_impl(dn, level, blkid, FALSE, tag, &db);
1967 1974 return (err ? NULL : db);
1968 1975 }
1969 1976
1970 1977 void
1971 1978 dbuf_create_bonus(dnode_t *dn)
1972 1979 {
1973 1980 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
1974 1981
1975 1982 ASSERT(dn->dn_bonus == NULL);
1976 1983 dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL);
1977 1984 }
1978 1985
1979 1986 int
1980 1987 dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
1981 1988 {
1982 1989 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1983 1990 dnode_t *dn;
1984 1991
1985 1992 if (db->db_blkid != DMU_SPILL_BLKID)
1986 1993 return (SET_ERROR(ENOTSUP));
1987 1994 if (blksz == 0)
1988 1995 blksz = SPA_MINBLOCKSIZE;
1989 1996 if (blksz > SPA_MAXBLOCKSIZE)
1990 1997 blksz = SPA_MAXBLOCKSIZE;
1991 1998 else
1992 1999 blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
1993 2000
1994 2001 DB_DNODE_ENTER(db);
1995 2002 dn = DB_DNODE(db);
1996 2003 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1997 2004 dbuf_new_size(db, blksz, tx);
1998 2005 rw_exit(&dn->dn_struct_rwlock);
1999 2006 DB_DNODE_EXIT(db);
2000 2007
2001 2008 return (0);
2002 2009 }
2003 2010
2004 2011 void
2005 2012 dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx)
2006 2013 {
2007 2014 dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx);
2008 2015 }
2009 2016
2010 2017 #pragma weak dmu_buf_add_ref = dbuf_add_ref
2011 2018 void
2012 2019 dbuf_add_ref(dmu_buf_impl_t *db, void *tag)
2013 2020 {
2014 2021 int64_t holds = refcount_add(&db->db_holds, tag);
2015 2022 ASSERT(holds > 1);
2016 2023 }
2017 2024
2018 2025 /*
2019 2026 * If you call dbuf_rele() you had better not be referencing the dnode handle
2020 2027 * unless you have some other direct or indirect hold on the dnode. (An indirect
2021 2028 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
2022 2029 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
2023 2030 * dnode's parent dbuf evicting its dnode handles.
2024 2031 */
2025 2032 #pragma weak dmu_buf_rele = dbuf_rele
2026 2033 void
2027 2034 dbuf_rele(dmu_buf_impl_t *db, void *tag)
2028 2035 {
2029 2036 mutex_enter(&db->db_mtx);
2030 2037 dbuf_rele_and_unlock(db, tag);
2031 2038 }
2032 2039
2033 2040 /*
2034 2041 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
2035 2042 * db_dirtycnt and db_holds to be updated atomically.
2036 2043 */
2037 2044 void
2038 2045 dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
2039 2046 {
2040 2047 int64_t holds;
2041 2048
2042 2049 ASSERT(MUTEX_HELD(&db->db_mtx));
2043 2050 DBUF_VERIFY(db);
2044 2051
2045 2052 /*
2046 2053 * Remove the reference to the dbuf before removing its hold on the
2047 2054 * dnode so we can guarantee in dnode_move() that a referenced bonus
2048 2055 * buffer has a corresponding dnode hold.
2049 2056 */
2050 2057 holds = refcount_remove(&db->db_holds, tag);
2051 2058 ASSERT(holds >= 0);
2052 2059
2053 2060 /*
2054 2061 * We can't freeze indirects if there is a possibility that they
2055 2062 * may be modified in the current syncing context.
2056 2063 */
2057 2064 if (db->db_buf && holds == (db->db_level == 0 ? db->db_dirtycnt : 0))
2058 2065 arc_buf_freeze(db->db_buf);
2059 2066
2060 2067 if (holds == db->db_dirtycnt &&
2061 2068 db->db_level == 0 && db->db_immediate_evict)
2062 2069 dbuf_evict_user(db);
2063 2070
2064 2071 if (holds == 0) {
2065 2072 if (db->db_blkid == DMU_BONUS_BLKID) {
2066 2073 mutex_exit(&db->db_mtx);
2067 2074
2068 2075 /*
2069 2076 * If the dnode moves here, we cannot cross this barrier
2070 2077 * until the move completes.
2071 2078 */
2072 2079 DB_DNODE_ENTER(db);
2073 2080 (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
2074 2081 DB_DNODE_EXIT(db);
2075 2082 /*
2076 2083 * The bonus buffer's dnode hold is no longer discounted
2077 2084 * in dnode_move(). The dnode cannot move until after
2078 2085 * the dnode_rele().
2079 2086 */
2080 2087 dnode_rele(DB_DNODE(db), db);
2081 2088 } else if (db->db_buf == NULL) {
2082 2089 /*
2083 2090 * This is a special case: we never associated this
2084 2091 * dbuf with any data allocated from the ARC.
2085 2092 */
2086 2093 ASSERT(db->db_state == DB_UNCACHED ||
2087 2094 db->db_state == DB_NOFILL);
2088 2095 dbuf_evict(db);
2089 2096 } else if (arc_released(db->db_buf)) {
2090 2097 arc_buf_t *buf = db->db_buf;
2091 2098 /*
2092 2099 * This dbuf has anonymous data associated with it.
2093 2100 */
2094 2101 dbuf_set_data(db, NULL);
2095 2102 VERIFY(arc_buf_remove_ref(buf, db));
2096 2103 dbuf_evict(db);
2097 2104 } else {
2098 2105 VERIFY(!arc_buf_remove_ref(db->db_buf, db));
2099 2106
2100 2107 /*
2101 2108 * A dbuf will be eligible for eviction if either the
2102 2109 * 'primarycache' property is set or a duplicate
2103 2110 * copy of this buffer is already cached in the arc.
2104 2111 *
2105 2112 * In the case of the 'primarycache' a buffer
2106 2113 * is considered for eviction if it matches the
2107 2114 * criteria set in the property.
2108 2115 *
2109 2116 * To decide if our buffer is considered a
2110 2117 * duplicate, we must call into the arc to determine
2111 2118 * if multiple buffers are referencing the same
2112 2119 * block on-disk. If so, then we simply evict
2113 2120 * ourselves.
2114 2121 */
2115 2122 if (!DBUF_IS_CACHEABLE(db) ||
2116 2123 arc_buf_eviction_needed(db->db_buf))
2117 2124 dbuf_clear(db);
2118 2125 else
2119 2126 mutex_exit(&db->db_mtx);
2120 2127 }
2121 2128 } else {
2122 2129 mutex_exit(&db->db_mtx);
2123 2130 }
2124 2131 }
2125 2132
2126 2133 #pragma weak dmu_buf_refcount = dbuf_refcount
2127 2134 uint64_t
2128 2135 dbuf_refcount(dmu_buf_impl_t *db)
2129 2136 {
2130 2137 return (refcount_count(&db->db_holds));
2131 2138 }
2132 2139
2133 2140 void *
2134 2141 dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2135 2142 dmu_buf_evict_func_t *evict_func)
2136 2143 {
2137 2144 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2138 2145 user_data_ptr_ptr, evict_func));
2139 2146 }
2140 2147
2141 2148 void *
2142 2149 dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
2143 2150 dmu_buf_evict_func_t *evict_func)
2144 2151 {
2145 2152 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2146 2153
2147 2154 db->db_immediate_evict = TRUE;
2148 2155 return (dmu_buf_update_user(db_fake, NULL, user_ptr,
2149 2156 user_data_ptr_ptr, evict_func));
2150 2157 }
2151 2158
2152 2159 void *
2153 2160 dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
2154 2161 void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
2155 2162 {
2156 2163 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2157 2164 ASSERT(db->db_level == 0);
2158 2165
2159 2166 ASSERT((user_ptr == NULL) == (evict_func == NULL));
2160 2167
2161 2168 mutex_enter(&db->db_mtx);
2162 2169
2163 2170 if (db->db_user_ptr == old_user_ptr) {
2164 2171 db->db_user_ptr = user_ptr;
2165 2172 db->db_user_data_ptr_ptr = user_data_ptr_ptr;
2166 2173 db->db_evict_func = evict_func;
2167 2174
2168 2175 dbuf_update_data(db);
2169 2176 } else {
2170 2177 old_user_ptr = db->db_user_ptr;
2171 2178 }
2172 2179
2173 2180 mutex_exit(&db->db_mtx);
2174 2181 return (old_user_ptr);
2175 2182 }
2176 2183
2177 2184 void *
2178 2185 dmu_buf_get_user(dmu_buf_t *db_fake)
2179 2186 {
2180 2187 dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
2181 2188 ASSERT(!refcount_is_zero(&db->db_holds));
2182 2189
2183 2190 return (db->db_user_ptr);
2184 2191 }
2185 2192
2186 2193 boolean_t
2187 2194 dmu_buf_freeable(dmu_buf_t *dbuf)
2188 2195 {
2189 2196 boolean_t res = B_FALSE;
2190 2197 dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
2191 2198
2192 2199 if (db->db_blkptr)
2193 2200 res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
2194 2201 db->db_blkptr, db->db_blkptr->blk_birth);
2195 2202
2196 2203 return (res);
2197 2204 }
2198 2205
2199 2206 blkptr_t *
2200 2207 dmu_buf_get_blkptr(dmu_buf_t *db)
2201 2208 {
2202 2209 dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
2203 2210 return (dbi->db_blkptr);
2204 2211 }
2205 2212
2206 2213 static void
2207 2214 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
2208 2215 {
2209 2216 /* ASSERT(dmu_tx_is_syncing(tx) */
2210 2217 ASSERT(MUTEX_HELD(&db->db_mtx));
2211 2218
2212 2219 if (db->db_blkptr != NULL)
2213 2220 return;
2214 2221
2215 2222 if (db->db_blkid == DMU_SPILL_BLKID) {
2216 2223 db->db_blkptr = &dn->dn_phys->dn_spill;
2217 2224 BP_ZERO(db->db_blkptr);
2218 2225 return;
2219 2226 }
2220 2227 if (db->db_level == dn->dn_phys->dn_nlevels-1) {
2221 2228 /*
2222 2229 * This buffer was allocated at a time when there was
2223 2230 * no available blkptrs from the dnode, or it was
2224 2231 * inappropriate to hook it in (i.e., nlevels mis-match).
2225 2232 */
2226 2233 ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr);
2227 2234 ASSERT(db->db_parent == NULL);
2228 2235 db->db_parent = dn->dn_dbuf;
2229 2236 db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid];
2230 2237 DBUF_VERIFY(db);
2231 2238 } else {
2232 2239 dmu_buf_impl_t *parent = db->db_parent;
2233 2240 int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2234 2241
2235 2242 ASSERT(dn->dn_phys->dn_nlevels > 1);
2236 2243 if (parent == NULL) {
2237 2244 mutex_exit(&db->db_mtx);
2238 2245 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2239 2246 (void) dbuf_hold_impl(dn, db->db_level+1,
2240 2247 db->db_blkid >> epbs, FALSE, db, &parent);
2241 2248 rw_exit(&dn->dn_struct_rwlock);
2242 2249 mutex_enter(&db->db_mtx);
2243 2250 db->db_parent = parent;
2244 2251 }
2245 2252 db->db_blkptr = (blkptr_t *)parent->db.db_data +
2246 2253 (db->db_blkid & ((1ULL << epbs) - 1));
2247 2254 DBUF_VERIFY(db);
2248 2255 }
2249 2256 }
2250 2257
2251 2258 static void
2252 2259 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2253 2260 {
2254 2261 dmu_buf_impl_t *db = dr->dr_dbuf;
2255 2262 dnode_t *dn;
2256 2263 zio_t *zio;
2257 2264
2258 2265 ASSERT(dmu_tx_is_syncing(tx));
2259 2266
2260 2267 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2261 2268
2262 2269 mutex_enter(&db->db_mtx);
2263 2270
2264 2271 ASSERT(db->db_level > 0);
2265 2272 DBUF_VERIFY(db);
2266 2273
2267 2274 /* Read the block if it hasn't been read yet. */
2268 2275 if (db->db_buf == NULL) {
2269 2276 mutex_exit(&db->db_mtx);
2270 2277 (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED);
2271 2278 mutex_enter(&db->db_mtx);
2272 2279 }
2273 2280 ASSERT3U(db->db_state, ==, DB_CACHED);
2274 2281 ASSERT(db->db_buf != NULL);
2275 2282
2276 2283 DB_DNODE_ENTER(db);
2277 2284 dn = DB_DNODE(db);
2278 2285 /* Indirect block size must match what the dnode thinks it is. */
2279 2286 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2280 2287 dbuf_check_blkptr(dn, db);
2281 2288 DB_DNODE_EXIT(db);
2282 2289
2283 2290 /* Provide the pending dirty record to child dbufs */
2284 2291 db->db_data_pending = dr;
2285 2292
2286 2293 mutex_exit(&db->db_mtx);
2287 2294 dbuf_write(dr, db->db_buf, tx);
2288 2295
2289 2296 zio = dr->dr_zio;
2290 2297 mutex_enter(&dr->dt.di.dr_mtx);
2291 2298 dbuf_sync_list(&dr->dt.di.dr_children, tx);
2292 2299 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2293 2300 mutex_exit(&dr->dt.di.dr_mtx);
2294 2301 zio_nowait(zio);
2295 2302 }
2296 2303
2297 2304 static void
2298 2305 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
2299 2306 {
2300 2307 arc_buf_t **datap = &dr->dt.dl.dr_data;
2301 2308 dmu_buf_impl_t *db = dr->dr_dbuf;
2302 2309 dnode_t *dn;
2303 2310 objset_t *os;
2304 2311 uint64_t txg = tx->tx_txg;
2305 2312
2306 2313 ASSERT(dmu_tx_is_syncing(tx));
2307 2314
2308 2315 dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr);
2309 2316
2310 2317 mutex_enter(&db->db_mtx);
2311 2318 /*
2312 2319 * To be synced, we must be dirtied. But we
2313 2320 * might have been freed after the dirty.
2314 2321 */
2315 2322 if (db->db_state == DB_UNCACHED) {
2316 2323 /* This buffer has been freed since it was dirtied */
2317 2324 ASSERT(db->db.db_data == NULL);
2318 2325 } else if (db->db_state == DB_FILL) {
2319 2326 /* This buffer was freed and is now being re-filled */
2320 2327 ASSERT(db->db.db_data != dr->dt.dl.dr_data);
2321 2328 } else {
2322 2329 ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL);
2323 2330 }
2324 2331 DBUF_VERIFY(db);
2325 2332
2326 2333 DB_DNODE_ENTER(db);
2327 2334 dn = DB_DNODE(db);
2328 2335
2329 2336 if (db->db_blkid == DMU_SPILL_BLKID) {
2330 2337 mutex_enter(&dn->dn_mtx);
2331 2338 dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR;
2332 2339 mutex_exit(&dn->dn_mtx);
2333 2340 }
2334 2341
2335 2342 /*
2336 2343 * If this is a bonus buffer, simply copy the bonus data into the
2337 2344 * dnode. It will be written out when the dnode is synced (and it
2338 2345 * will be synced, since it must have been dirty for dbuf_sync to
2339 2346 * be called).
2340 2347 */
2341 2348 if (db->db_blkid == DMU_BONUS_BLKID) {
2342 2349 dbuf_dirty_record_t **drp;
2343 2350
2344 2351 ASSERT(*datap != NULL);
2345 2352 ASSERT0(db->db_level);
2346 2353 ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
2347 2354 bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
2348 2355 DB_DNODE_EXIT(db);
2349 2356
2350 2357 if (*datap != db->db.db_data) {
2351 2358 zio_buf_free(*datap, DN_MAX_BONUSLEN);
2352 2359 arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
2353 2360 }
2354 2361 db->db_data_pending = NULL;
2355 2362 drp = &db->db_last_dirty;
2356 2363 while (*drp != dr)
2357 2364 drp = &(*drp)->dr_next;
2358 2365 ASSERT(dr->dr_next == NULL);
2359 2366 ASSERT(dr->dr_dbuf == db);
2360 2367 *drp = dr->dr_next;
2361 2368 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2362 2369 ASSERT(db->db_dirtycnt > 0);
2363 2370 db->db_dirtycnt -= 1;
2364 2371 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2365 2372 return;
2366 2373 }
2367 2374
2368 2375 os = dn->dn_objset;
2369 2376
2370 2377 /*
2371 2378 * This function may have dropped the db_mtx lock allowing a dmu_sync
2372 2379 * operation to sneak in. As a result, we need to ensure that we
2373 2380 * don't check the dr_override_state until we have returned from
2374 2381 * dbuf_check_blkptr.
2375 2382 */
2376 2383 dbuf_check_blkptr(dn, db);
2377 2384
2378 2385 /*
2379 2386 * If this buffer is in the middle of an immediate write,
2380 2387 * wait for the synchronous IO to complete.
2381 2388 */
2382 2389 while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
2383 2390 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
2384 2391 cv_wait(&db->db_changed, &db->db_mtx);
2385 2392 ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN);
2386 2393 }
2387 2394
2388 2395 if (db->db_state != DB_NOFILL &&
2389 2396 dn->dn_object != DMU_META_DNODE_OBJECT &&
2390 2397 refcount_count(&db->db_holds) > 1 &&
2391 2398 dr->dt.dl.dr_override_state != DR_OVERRIDDEN &&
2392 2399 *datap == db->db_buf) {
2393 2400 /*
2394 2401 * If this buffer is currently "in use" (i.e., there
2395 2402 * are active holds and db_data still references it),
2396 2403 * then make a copy before we start the write so that
2397 2404 * any modifications from the open txg will not leak
2398 2405 * into this write.
2399 2406 *
2400 2407 * NOTE: this copy does not need to be made for
2401 2408 * objects only modified in the syncing context (e.g.
2402 2409 * DNONE_DNODE blocks).
2403 2410 */
2404 2411 int blksz = arc_buf_size(*datap);
2405 2412 arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
2406 2413 *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
2407 2414 bcopy(db->db.db_data, (*datap)->b_data, blksz);
2408 2415 }
2409 2416 db->db_data_pending = dr;
2410 2417
2411 2418 mutex_exit(&db->db_mtx);
2412 2419
2413 2420 dbuf_write(dr, *datap, tx);
2414 2421
2415 2422 ASSERT(!list_link_active(&dr->dr_dirty_node));
2416 2423 if (dn->dn_object == DMU_META_DNODE_OBJECT) {
2417 2424 list_insert_tail(&dn->dn_dirty_records[txg&TXG_MASK], dr);
2418 2425 DB_DNODE_EXIT(db);
2419 2426 } else {
2420 2427 /*
2421 2428 * Although zio_nowait() does not "wait for an IO", it does
2422 2429 * initiate the IO. If this is an empty write it seems plausible
2423 2430 * that the IO could actually be completed before the nowait
2424 2431 * returns. We need to DB_DNODE_EXIT() first in case
2425 2432 * zio_nowait() invalidates the dbuf.
2426 2433 */
2427 2434 DB_DNODE_EXIT(db);
2428 2435 zio_nowait(dr->dr_zio);
2429 2436 }
2430 2437 }
2431 2438
2432 2439 void
2433 2440 dbuf_sync_list(list_t *list, dmu_tx_t *tx)
2434 2441 {
2435 2442 dbuf_dirty_record_t *dr;
2436 2443
2437 2444 while (dr = list_head(list)) {
2438 2445 if (dr->dr_zio != NULL) {
2439 2446 /*
2440 2447 * If we find an already initialized zio then we
2441 2448 * are processing the meta-dnode, and we have finished.
2442 2449 * The dbufs for all dnodes are put back on the list
2443 2450 * during processing, so that we can zio_wait()
2444 2451 * these IOs after initiating all child IOs.
2445 2452 */
2446 2453 ASSERT3U(dr->dr_dbuf->db.db_object, ==,
2447 2454 DMU_META_DNODE_OBJECT);
2448 2455 break;
2449 2456 }
2450 2457 list_remove(list, dr);
2451 2458 if (dr->dr_dbuf->db_level > 0)
2452 2459 dbuf_sync_indirect(dr, tx);
2453 2460 else
2454 2461 dbuf_sync_leaf(dr, tx);
2455 2462 }
2456 2463 }
2457 2464
2458 2465 /* ARGSUSED */
2459 2466 static void
2460 2467 dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb)
2461 2468 {
2462 2469 dmu_buf_impl_t *db = vdb;
2463 2470 dnode_t *dn;
2464 2471 blkptr_t *bp = zio->io_bp;
2465 2472 blkptr_t *bp_orig = &zio->io_bp_orig;
2466 2473 spa_t *spa = zio->io_spa;
2467 2474 int64_t delta;
2468 2475 uint64_t fill = 0;
2469 2476 int i;
2470 2477
2471 2478 ASSERT(db->db_blkptr == bp);
2472 2479
2473 2480 DB_DNODE_ENTER(db);
2474 2481 dn = DB_DNODE(db);
2475 2482 delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig);
2476 2483 dnode_diduse_space(dn, delta - zio->io_prev_space_delta);
2477 2484 zio->io_prev_space_delta = delta;
2478 2485
2479 2486 if (BP_IS_HOLE(bp)) {
2480 2487 ASSERT(bp->blk_fill == 0);
2481 2488 DB_DNODE_EXIT(db);
2482 2489 return;
2483 2490 }
2484 2491
2485 2492 ASSERT((db->db_blkid != DMU_SPILL_BLKID &&
2486 2493 BP_GET_TYPE(bp) == dn->dn_type) ||
2487 2494 (db->db_blkid == DMU_SPILL_BLKID &&
2488 2495 BP_GET_TYPE(bp) == dn->dn_bonustype));
2489 2496 ASSERT(BP_GET_LEVEL(bp) == db->db_level);
2490 2497
2491 2498 mutex_enter(&db->db_mtx);
2492 2499
2493 2500 #ifdef ZFS_DEBUG
2494 2501 if (db->db_blkid == DMU_SPILL_BLKID) {
2495 2502 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2496 2503 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2497 2504 db->db_blkptr == &dn->dn_phys->dn_spill);
2498 2505 }
2499 2506 #endif
2500 2507
2501 2508 if (db->db_level == 0) {
2502 2509 mutex_enter(&dn->dn_mtx);
2503 2510 if (db->db_blkid > dn->dn_phys->dn_maxblkid &&
2504 2511 db->db_blkid != DMU_SPILL_BLKID)
2505 2512 dn->dn_phys->dn_maxblkid = db->db_blkid;
2506 2513 mutex_exit(&dn->dn_mtx);
2507 2514
2508 2515 if (dn->dn_type == DMU_OT_DNODE) {
2509 2516 dnode_phys_t *dnp = db->db.db_data;
2510 2517 for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
2511 2518 i--, dnp++) {
2512 2519 if (dnp->dn_type != DMU_OT_NONE)
2513 2520 fill++;
2514 2521 }
2515 2522 } else {
2516 2523 fill = 1;
2517 2524 }
2518 2525 } else {
2519 2526 blkptr_t *ibp = db->db.db_data;
2520 2527 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2521 2528 for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) {
2522 2529 if (BP_IS_HOLE(ibp))
2523 2530 continue;
|
↓ open down ↓ |
660 lines elided |
↑ open up ↑ |
2524 2531 fill += ibp->blk_fill;
2525 2532 }
2526 2533 }
2527 2534 DB_DNODE_EXIT(db);
2528 2535
2529 2536 bp->blk_fill = fill;
2530 2537
2531 2538 mutex_exit(&db->db_mtx);
2532 2539 }
2533 2540
2541 +/*
2542 + * The SPA will call this callback several times for each zio - once
2543 + * for every physical child i/o (zio->io_phys_children times). This
2544 + * allows the DMU to monitor the progress of each logical i/o. For example,
2545 + * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
2546 + * block. There may be a long delay before all copies/fragments are completed,
2547 + * so this callback allows us to retire dirty space gradually, as the physical
2548 + * i/os complete.
2549 + */
2534 2550 /* ARGSUSED */
2535 2551 static void
2552 +dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg)
2553 +{
2554 + dmu_buf_impl_t *db = arg;
2555 + objset_t *os = db->db_objset;
2556 + dsl_pool_t *dp = dmu_objset_pool(os);
2557 + dbuf_dirty_record_t *dr;
2558 + int delta = 0;
2559 +
2560 + dr = db->db_data_pending;
2561 + ASSERT3U(dr->dr_txg, ==, zio->io_txg);
2562 +
2563 + /*
2564 + * The callback will be called io_phys_children times. Retire one
2565 + * portion of our dirty space each time we are called. Any rounding
2566 + * error will be cleaned up by dsl_pool_sync()'s call to
2567 + * dsl_pool_undirty_space().
2568 + */
2569 + delta = dr->dr_accounted / zio->io_phys_children;
2570 + dsl_pool_undirty_space(dp, delta, zio->io_txg);
2571 +}
2572 +
2573 +/* ARGSUSED */
2574 +static void
2536 2575 dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
2537 2576 {
2538 2577 dmu_buf_impl_t *db = vdb;
2539 2578 blkptr_t *bp = zio->io_bp;
2540 2579 blkptr_t *bp_orig = &zio->io_bp_orig;
2541 2580 uint64_t txg = zio->io_txg;
2542 2581 dbuf_dirty_record_t **drp, *dr;
2543 2582
2544 2583 ASSERT0(zio->io_error);
2545 2584 ASSERT(db->db_blkptr == bp);
2546 2585
2547 2586 /*
2548 2587 * For nopwrites and rewrites we ensure that the bp matches our
2549 2588 * original and bypass all the accounting.
2550 2589 */
2551 2590 if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) {
2552 2591 ASSERT(BP_EQUAL(bp, bp_orig));
2553 2592 } else {
2554 2593 objset_t *os;
2555 2594 dsl_dataset_t *ds;
2556 2595 dmu_tx_t *tx;
2557 2596
2558 2597 DB_GET_OBJSET(&os, db);
2559 2598 ds = os->os_dsl_dataset;
2560 2599 tx = os->os_synctx;
2561 2600
2562 2601 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
2563 2602 dsl_dataset_block_born(ds, bp, tx);
2564 2603 }
2565 2604
2566 2605 mutex_enter(&db->db_mtx);
2567 2606
2568 2607 DBUF_VERIFY(db);
2569 2608
2570 2609 drp = &db->db_last_dirty;
2571 2610 while ((dr = *drp) != db->db_data_pending)
2572 2611 drp = &dr->dr_next;
2573 2612 ASSERT(!list_link_active(&dr->dr_dirty_node));
2574 2613 ASSERT(dr->dr_txg == txg);
2575 2614 ASSERT(dr->dr_dbuf == db);
2576 2615 ASSERT(dr->dr_next == NULL);
2577 2616 *drp = dr->dr_next;
2578 2617
2579 2618 #ifdef ZFS_DEBUG
2580 2619 if (db->db_blkid == DMU_SPILL_BLKID) {
2581 2620 dnode_t *dn;
2582 2621
2583 2622 DB_DNODE_ENTER(db);
2584 2623 dn = DB_DNODE(db);
2585 2624 ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR);
2586 2625 ASSERT(!(BP_IS_HOLE(db->db_blkptr)) &&
2587 2626 db->db_blkptr == &dn->dn_phys->dn_spill);
2588 2627 DB_DNODE_EXIT(db);
2589 2628 }
2590 2629 #endif
2591 2630
2592 2631 if (db->db_level == 0) {
2593 2632 ASSERT(db->db_blkid != DMU_BONUS_BLKID);
2594 2633 ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
2595 2634 if (db->db_state != DB_NOFILL) {
2596 2635 if (dr->dt.dl.dr_data != db->db_buf)
2597 2636 VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
2598 2637 db));
2599 2638 else if (!arc_released(db->db_buf))
2600 2639 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2601 2640 }
2602 2641 } else {
2603 2642 dnode_t *dn;
2604 2643
2605 2644 DB_DNODE_ENTER(db);
2606 2645 dn = DB_DNODE(db);
2607 2646 ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
2608 2647 ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
2609 2648 if (!BP_IS_HOLE(db->db_blkptr)) {
2610 2649 int epbs =
2611 2650 dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2612 2651 ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
2613 2652 db->db.db_size);
2614 2653 ASSERT3U(dn->dn_phys->dn_maxblkid
2615 2654 >> (db->db_level * epbs), >=, db->db_blkid);
2616 2655 arc_set_callback(db->db_buf, dbuf_do_evict, db);
2617 2656 }
|
↓ open down ↓ |
72 lines elided |
↑ open up ↑ |
2618 2657 DB_DNODE_EXIT(db);
2619 2658 mutex_destroy(&dr->dt.di.dr_mtx);
2620 2659 list_destroy(&dr->dt.di.dr_children);
2621 2660 }
2622 2661 kmem_free(dr, sizeof (dbuf_dirty_record_t));
2623 2662
2624 2663 cv_broadcast(&db->db_changed);
2625 2664 ASSERT(db->db_dirtycnt > 0);
2626 2665 db->db_dirtycnt -= 1;
2627 2666 db->db_data_pending = NULL;
2667 +
2628 2668 dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
2629 2669 }
2630 2670
2631 2671 static void
2632 2672 dbuf_write_nofill_ready(zio_t *zio)
2633 2673 {
2634 2674 dbuf_write_ready(zio, NULL, zio->io_private);
2635 2675 }
2636 2676
2637 2677 static void
2638 2678 dbuf_write_nofill_done(zio_t *zio)
2639 2679 {
2640 2680 dbuf_write_done(zio, NULL, zio->io_private);
2641 2681 }
2642 2682
2643 2683 static void
2644 2684 dbuf_write_override_ready(zio_t *zio)
2645 2685 {
2646 2686 dbuf_dirty_record_t *dr = zio->io_private;
2647 2687 dmu_buf_impl_t *db = dr->dr_dbuf;
2648 2688
2649 2689 dbuf_write_ready(zio, NULL, db);
2650 2690 }
2651 2691
2652 2692 static void
2653 2693 dbuf_write_override_done(zio_t *zio)
2654 2694 {
2655 2695 dbuf_dirty_record_t *dr = zio->io_private;
2656 2696 dmu_buf_impl_t *db = dr->dr_dbuf;
2657 2697 blkptr_t *obp = &dr->dt.dl.dr_overridden_by;
2658 2698
2659 2699 mutex_enter(&db->db_mtx);
2660 2700 if (!BP_EQUAL(zio->io_bp, obp)) {
2661 2701 if (!BP_IS_HOLE(obp))
2662 2702 dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp);
2663 2703 arc_release(dr->dt.dl.dr_data, db);
2664 2704 }
2665 2705 mutex_exit(&db->db_mtx);
2666 2706
2667 2707 dbuf_write_done(zio, NULL, db);
2668 2708 }
2669 2709
2670 2710 /* Issue I/O to commit a dirty buffer to disk. */
2671 2711 static void
2672 2712 dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
2673 2713 {
2674 2714 dmu_buf_impl_t *db = dr->dr_dbuf;
2675 2715 dnode_t *dn;
2676 2716 objset_t *os;
2677 2717 dmu_buf_impl_t *parent = db->db_parent;
2678 2718 uint64_t txg = tx->tx_txg;
2679 2719 zbookmark_t zb;
2680 2720 zio_prop_t zp;
2681 2721 zio_t *zio;
2682 2722 int wp_flag = 0;
2683 2723
2684 2724 DB_DNODE_ENTER(db);
2685 2725 dn = DB_DNODE(db);
2686 2726 os = dn->dn_objset;
2687 2727
2688 2728 if (db->db_state != DB_NOFILL) {
2689 2729 if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) {
2690 2730 /*
2691 2731 * Private object buffers are released here rather
2692 2732 * than in dbuf_dirty() since they are only modified
2693 2733 * in the syncing context and we don't want the
2694 2734 * overhead of making multiple copies of the data.
2695 2735 */
2696 2736 if (BP_IS_HOLE(db->db_blkptr)) {
2697 2737 arc_buf_thaw(data);
2698 2738 } else {
2699 2739 dbuf_release_bp(db);
2700 2740 }
2701 2741 }
2702 2742 }
2703 2743
2704 2744 if (parent != dn->dn_dbuf) {
2705 2745 /* Our parent is an indirect block. */
2706 2746 /* We have a dirty parent that has been scheduled for write. */
2707 2747 ASSERT(parent && parent->db_data_pending);
2708 2748 /* Our parent's buffer is one level closer to the dnode. */
2709 2749 ASSERT(db->db_level == parent->db_level-1);
2710 2750 /*
2711 2751 * We're about to modify our parent's db_data by modifying
2712 2752 * our block pointer, so the parent must be released.
2713 2753 */
2714 2754 ASSERT(arc_released(parent->db_buf));
2715 2755 zio = parent->db_data_pending->dr_zio;
2716 2756 } else {
2717 2757 /* Our parent is the dnode itself. */
2718 2758 ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 &&
2719 2759 db->db_blkid != DMU_SPILL_BLKID) ||
2720 2760 (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0));
2721 2761 if (db->db_blkid != DMU_SPILL_BLKID)
2722 2762 ASSERT3P(db->db_blkptr, ==,
2723 2763 &dn->dn_phys->dn_blkptr[db->db_blkid]);
2724 2764 zio = dn->dn_zio;
2725 2765 }
2726 2766
2727 2767 ASSERT(db->db_level == 0 || data == db->db_buf);
2728 2768 ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
2729 2769 ASSERT(zio);
2730 2770
2731 2771 SET_BOOKMARK(&zb, os->os_dsl_dataset ?
2732 2772 os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
2733 2773 db->db.db_object, db->db_level, db->db_blkid);
2734 2774
2735 2775 if (db->db_blkid == DMU_SPILL_BLKID)
|
↓ open down ↓ |
98 lines elided |
↑ open up ↑ |
2736 2776 wp_flag = WP_SPILL;
2737 2777 wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
2738 2778
2739 2779 dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
2740 2780 DB_DNODE_EXIT(db);
2741 2781
2742 2782 if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
2743 2783 ASSERT(db->db_state != DB_NOFILL);
2744 2784 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2745 2785 db->db_blkptr, data->b_data, arc_buf_size(data), &zp,
2746 - dbuf_write_override_ready, dbuf_write_override_done, dr,
2747 - ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2786 + dbuf_write_override_ready, NULL, dbuf_write_override_done,
2787 + dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2748 2788 mutex_enter(&db->db_mtx);
2749 2789 dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
2750 2790 zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by,
2751 2791 dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite);
2752 2792 mutex_exit(&db->db_mtx);
2753 2793 } else if (db->db_state == DB_NOFILL) {
2754 2794 ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF);
2755 2795 dr->dr_zio = zio_write(zio, os->os_spa, txg,
2756 2796 db->db_blkptr, NULL, db->db.db_size, &zp,
2757 - dbuf_write_nofill_ready, dbuf_write_nofill_done, db,
2797 + dbuf_write_nofill_ready, NULL, dbuf_write_nofill_done, db,
2758 2798 ZIO_PRIORITY_ASYNC_WRITE,
2759 2799 ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
2760 2800 } else {
2761 2801 ASSERT(arc_released(data));
2762 2802 dr->dr_zio = arc_write(zio, os->os_spa, txg,
2763 2803 db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db),
2764 2804 DBUF_IS_L2COMPRESSIBLE(db), &zp, dbuf_write_ready,
2765 - dbuf_write_done, db, ZIO_PRIORITY_ASYNC_WRITE,
2766 - ZIO_FLAG_MUSTSUCCEED, &zb);
2805 + dbuf_write_physdone, dbuf_write_done, db,
2806 + ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
2767 2807 }
2768 2808 }
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX