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3741 zfs needs better comments
Submitted by: Will Andrews <willa@spectralogic.com>
Submitted by: Justin Gibbs <justing@spectralogic.com>
Submitted by: Alan Somers <alans@spectralogic.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
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--- old/usr/src/uts/common/fs/zfs/dmu_tx.c
+++ new/usr/src/uts/common/fs/zfs/dmu_tx.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 */
26 26
27 27 #include <sys/dmu.h>
28 28 #include <sys/dmu_impl.h>
29 29 #include <sys/dbuf.h>
30 30 #include <sys/dmu_tx.h>
31 31 #include <sys/dmu_objset.h>
32 32 #include <sys/dsl_dataset.h> /* for dsl_dataset_block_freeable() */
33 33 #include <sys/dsl_dir.h> /* for dsl_dir_tempreserve_*() */
34 34 #include <sys/dsl_pool.h>
35 35 #include <sys/zap_impl.h> /* for fzap_default_block_shift */
36 36 #include <sys/spa.h>
37 37 #include <sys/sa.h>
38 38 #include <sys/sa_impl.h>
39 39 #include <sys/zfs_context.h>
40 40 #include <sys/varargs.h>
41 41
42 42 typedef void (*dmu_tx_hold_func_t)(dmu_tx_t *tx, struct dnode *dn,
43 43 uint64_t arg1, uint64_t arg2);
44 44
45 45
46 46 dmu_tx_t *
47 47 dmu_tx_create_dd(dsl_dir_t *dd)
48 48 {
49 49 dmu_tx_t *tx = kmem_zalloc(sizeof (dmu_tx_t), KM_SLEEP);
50 50 tx->tx_dir = dd;
51 51 if (dd != NULL)
52 52 tx->tx_pool = dd->dd_pool;
53 53 list_create(&tx->tx_holds, sizeof (dmu_tx_hold_t),
54 54 offsetof(dmu_tx_hold_t, txh_node));
55 55 list_create(&tx->tx_callbacks, sizeof (dmu_tx_callback_t),
56 56 offsetof(dmu_tx_callback_t, dcb_node));
57 57 #ifdef ZFS_DEBUG
58 58 refcount_create(&tx->tx_space_written);
59 59 refcount_create(&tx->tx_space_freed);
60 60 #endif
61 61 return (tx);
62 62 }
63 63
64 64 dmu_tx_t *
65 65 dmu_tx_create(objset_t *os)
66 66 {
67 67 dmu_tx_t *tx = dmu_tx_create_dd(os->os_dsl_dataset->ds_dir);
68 68 tx->tx_objset = os;
69 69 tx->tx_lastsnap_txg = dsl_dataset_prev_snap_txg(os->os_dsl_dataset);
70 70 return (tx);
71 71 }
72 72
73 73 dmu_tx_t *
74 74 dmu_tx_create_assigned(struct dsl_pool *dp, uint64_t txg)
75 75 {
76 76 dmu_tx_t *tx = dmu_tx_create_dd(NULL);
77 77
78 78 ASSERT3U(txg, <=, dp->dp_tx.tx_open_txg);
79 79 tx->tx_pool = dp;
80 80 tx->tx_txg = txg;
81 81 tx->tx_anyobj = TRUE;
82 82
83 83 return (tx);
84 84 }
85 85
86 86 int
87 87 dmu_tx_is_syncing(dmu_tx_t *tx)
88 88 {
89 89 return (tx->tx_anyobj);
90 90 }
91 91
92 92 int
93 93 dmu_tx_private_ok(dmu_tx_t *tx)
94 94 {
95 95 return (tx->tx_anyobj);
96 96 }
97 97
98 98 static dmu_tx_hold_t *
99 99 dmu_tx_hold_object_impl(dmu_tx_t *tx, objset_t *os, uint64_t object,
100 100 enum dmu_tx_hold_type type, uint64_t arg1, uint64_t arg2)
101 101 {
102 102 dmu_tx_hold_t *txh;
103 103 dnode_t *dn = NULL;
104 104 int err;
105 105
106 106 if (object != DMU_NEW_OBJECT) {
107 107 err = dnode_hold(os, object, tx, &dn);
108 108 if (err) {
109 109 tx->tx_err = err;
110 110 return (NULL);
111 111 }
112 112
113 113 if (err == 0 && tx->tx_txg != 0) {
114 114 mutex_enter(&dn->dn_mtx);
115 115 /*
116 116 * dn->dn_assigned_txg == tx->tx_txg doesn't pose a
117 117 * problem, but there's no way for it to happen (for
118 118 * now, at least).
119 119 */
120 120 ASSERT(dn->dn_assigned_txg == 0);
121 121 dn->dn_assigned_txg = tx->tx_txg;
122 122 (void) refcount_add(&dn->dn_tx_holds, tx);
123 123 mutex_exit(&dn->dn_mtx);
124 124 }
125 125 }
126 126
127 127 txh = kmem_zalloc(sizeof (dmu_tx_hold_t), KM_SLEEP);
128 128 txh->txh_tx = tx;
129 129 txh->txh_dnode = dn;
130 130 #ifdef ZFS_DEBUG
131 131 txh->txh_type = type;
132 132 txh->txh_arg1 = arg1;
133 133 txh->txh_arg2 = arg2;
134 134 #endif
135 135 list_insert_tail(&tx->tx_holds, txh);
136 136
137 137 return (txh);
138 138 }
139 139
140 140 void
141 141 dmu_tx_add_new_object(dmu_tx_t *tx, objset_t *os, uint64_t object)
142 142 {
143 143 /*
144 144 * If we're syncing, they can manipulate any object anyhow, and
145 145 * the hold on the dnode_t can cause problems.
146 146 */
147 147 if (!dmu_tx_is_syncing(tx)) {
148 148 (void) dmu_tx_hold_object_impl(tx, os,
149 149 object, THT_NEWOBJECT, 0, 0);
150 150 }
151 151 }
152 152
153 153 static int
154 154 dmu_tx_check_ioerr(zio_t *zio, dnode_t *dn, int level, uint64_t blkid)
155 155 {
156 156 int err;
157 157 dmu_buf_impl_t *db;
158 158
159 159 rw_enter(&dn->dn_struct_rwlock, RW_READER);
160 160 db = dbuf_hold_level(dn, level, blkid, FTAG);
161 161 rw_exit(&dn->dn_struct_rwlock);
162 162 if (db == NULL)
163 163 return (SET_ERROR(EIO));
164 164 err = dbuf_read(db, zio, DB_RF_CANFAIL | DB_RF_NOPREFETCH);
165 165 dbuf_rele(db, FTAG);
166 166 return (err);
167 167 }
168 168
169 169 static void
170 170 dmu_tx_count_twig(dmu_tx_hold_t *txh, dnode_t *dn, dmu_buf_impl_t *db,
171 171 int level, uint64_t blkid, boolean_t freeable, uint64_t *history)
172 172 {
173 173 objset_t *os = dn->dn_objset;
174 174 dsl_dataset_t *ds = os->os_dsl_dataset;
175 175 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
176 176 dmu_buf_impl_t *parent = NULL;
177 177 blkptr_t *bp = NULL;
178 178 uint64_t space;
179 179
180 180 if (level >= dn->dn_nlevels || history[level] == blkid)
181 181 return;
182 182
183 183 history[level] = blkid;
184 184
185 185 space = (level == 0) ? dn->dn_datablksz : (1ULL << dn->dn_indblkshift);
186 186
187 187 if (db == NULL || db == dn->dn_dbuf) {
188 188 ASSERT(level != 0);
189 189 db = NULL;
190 190 } else {
191 191 ASSERT(DB_DNODE(db) == dn);
192 192 ASSERT(db->db_level == level);
193 193 ASSERT(db->db.db_size == space);
194 194 ASSERT(db->db_blkid == blkid);
195 195 bp = db->db_blkptr;
196 196 parent = db->db_parent;
197 197 }
198 198
199 199 freeable = (bp && (freeable ||
200 200 dsl_dataset_block_freeable(ds, bp, bp->blk_birth)));
201 201
202 202 if (freeable)
203 203 txh->txh_space_tooverwrite += space;
204 204 else
205 205 txh->txh_space_towrite += space;
206 206 if (bp)
207 207 txh->txh_space_tounref += bp_get_dsize(os->os_spa, bp);
208 208
209 209 dmu_tx_count_twig(txh, dn, parent, level + 1,
210 210 blkid >> epbs, freeable, history);
211 211 }
212 212
213 213 /* ARGSUSED */
214 214 static void
215 215 dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
216 216 {
217 217 dnode_t *dn = txh->txh_dnode;
218 218 uint64_t start, end, i;
219 219 int min_bs, max_bs, min_ibs, max_ibs, epbs, bits;
220 220 int err = 0;
221 221
222 222 if (len == 0)
223 223 return;
224 224
225 225 min_bs = SPA_MINBLOCKSHIFT;
226 226 max_bs = SPA_MAXBLOCKSHIFT;
227 227 min_ibs = DN_MIN_INDBLKSHIFT;
228 228 max_ibs = DN_MAX_INDBLKSHIFT;
229 229
230 230 if (dn) {
231 231 uint64_t history[DN_MAX_LEVELS];
232 232 int nlvls = dn->dn_nlevels;
233 233 int delta;
234 234
235 235 /*
236 236 * For i/o error checking, read the first and last level-0
237 237 * blocks (if they are not aligned), and all the level-1 blocks.
238 238 */
239 239 if (dn->dn_maxblkid == 0) {
240 240 delta = dn->dn_datablksz;
241 241 start = (off < dn->dn_datablksz) ? 0 : 1;
242 242 end = (off+len <= dn->dn_datablksz) ? 0 : 1;
243 243 if (start == 0 && (off > 0 || len < dn->dn_datablksz)) {
244 244 err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
245 245 if (err)
246 246 goto out;
247 247 delta -= off;
248 248 }
249 249 } else {
250 250 zio_t *zio = zio_root(dn->dn_objset->os_spa,
251 251 NULL, NULL, ZIO_FLAG_CANFAIL);
252 252
253 253 /* first level-0 block */
254 254 start = off >> dn->dn_datablkshift;
255 255 if (P2PHASE(off, dn->dn_datablksz) ||
256 256 len < dn->dn_datablksz) {
257 257 err = dmu_tx_check_ioerr(zio, dn, 0, start);
258 258 if (err)
259 259 goto out;
260 260 }
261 261
262 262 /* last level-0 block */
263 263 end = (off+len-1) >> dn->dn_datablkshift;
264 264 if (end != start && end <= dn->dn_maxblkid &&
265 265 P2PHASE(off+len, dn->dn_datablksz)) {
266 266 err = dmu_tx_check_ioerr(zio, dn, 0, end);
267 267 if (err)
268 268 goto out;
269 269 }
270 270
271 271 /* level-1 blocks */
272 272 if (nlvls > 1) {
273 273 int shft = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
274 274 for (i = (start>>shft)+1; i < end>>shft; i++) {
275 275 err = dmu_tx_check_ioerr(zio, dn, 1, i);
276 276 if (err)
277 277 goto out;
278 278 }
279 279 }
280 280
281 281 err = zio_wait(zio);
282 282 if (err)
283 283 goto out;
284 284 delta = P2NPHASE(off, dn->dn_datablksz);
285 285 }
286 286
287 287 min_ibs = max_ibs = dn->dn_indblkshift;
288 288 if (dn->dn_maxblkid > 0) {
289 289 /*
290 290 * The blocksize can't change,
291 291 * so we can make a more precise estimate.
292 292 */
293 293 ASSERT(dn->dn_datablkshift != 0);
294 294 min_bs = max_bs = dn->dn_datablkshift;
295 295 }
296 296
297 297 /*
298 298 * If this write is not off the end of the file
299 299 * we need to account for overwrites/unref.
300 300 */
301 301 if (start <= dn->dn_maxblkid) {
302 302 for (int l = 0; l < DN_MAX_LEVELS; l++)
303 303 history[l] = -1ULL;
304 304 }
305 305 while (start <= dn->dn_maxblkid) {
306 306 dmu_buf_impl_t *db;
307 307
308 308 rw_enter(&dn->dn_struct_rwlock, RW_READER);
309 309 err = dbuf_hold_impl(dn, 0, start, FALSE, FTAG, &db);
310 310 rw_exit(&dn->dn_struct_rwlock);
311 311
312 312 if (err) {
313 313 txh->txh_tx->tx_err = err;
314 314 return;
315 315 }
316 316
317 317 dmu_tx_count_twig(txh, dn, db, 0, start, B_FALSE,
318 318 history);
319 319 dbuf_rele(db, FTAG);
320 320 if (++start > end) {
321 321 /*
322 322 * Account for new indirects appearing
323 323 * before this IO gets assigned into a txg.
324 324 */
325 325 bits = 64 - min_bs;
326 326 epbs = min_ibs - SPA_BLKPTRSHIFT;
327 327 for (bits -= epbs * (nlvls - 1);
328 328 bits >= 0; bits -= epbs)
329 329 txh->txh_fudge += 1ULL << max_ibs;
330 330 goto out;
331 331 }
332 332 off += delta;
333 333 if (len >= delta)
334 334 len -= delta;
335 335 delta = dn->dn_datablksz;
336 336 }
337 337 }
338 338
339 339 /*
340 340 * 'end' is the last thing we will access, not one past.
341 341 * This way we won't overflow when accessing the last byte.
342 342 */
343 343 start = P2ALIGN(off, 1ULL << max_bs);
344 344 end = P2ROUNDUP(off + len, 1ULL << max_bs) - 1;
345 345 txh->txh_space_towrite += end - start + 1;
346 346
347 347 start >>= min_bs;
348 348 end >>= min_bs;
349 349
350 350 epbs = min_ibs - SPA_BLKPTRSHIFT;
351 351
352 352 /*
353 353 * The object contains at most 2^(64 - min_bs) blocks,
354 354 * and each indirect level maps 2^epbs.
355 355 */
356 356 for (bits = 64 - min_bs; bits >= 0; bits -= epbs) {
357 357 start >>= epbs;
358 358 end >>= epbs;
359 359 ASSERT3U(end, >=, start);
360 360 txh->txh_space_towrite += (end - start + 1) << max_ibs;
361 361 if (start != 0) {
362 362 /*
363 363 * We also need a new blkid=0 indirect block
364 364 * to reference any existing file data.
365 365 */
366 366 txh->txh_space_towrite += 1ULL << max_ibs;
367 367 }
368 368 }
369 369
370 370 out:
371 371 if (txh->txh_space_towrite + txh->txh_space_tooverwrite >
372 372 2 * DMU_MAX_ACCESS)
373 373 err = SET_ERROR(EFBIG);
374 374
375 375 if (err)
376 376 txh->txh_tx->tx_err = err;
377 377 }
378 378
379 379 static void
380 380 dmu_tx_count_dnode(dmu_tx_hold_t *txh)
381 381 {
382 382 dnode_t *dn = txh->txh_dnode;
383 383 dnode_t *mdn = DMU_META_DNODE(txh->txh_tx->tx_objset);
384 384 uint64_t space = mdn->dn_datablksz +
385 385 ((mdn->dn_nlevels-1) << mdn->dn_indblkshift);
386 386
387 387 if (dn && dn->dn_dbuf->db_blkptr &&
388 388 dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
389 389 dn->dn_dbuf->db_blkptr, dn->dn_dbuf->db_blkptr->blk_birth)) {
390 390 txh->txh_space_tooverwrite += space;
391 391 txh->txh_space_tounref += space;
392 392 } else {
393 393 txh->txh_space_towrite += space;
394 394 if (dn && dn->dn_dbuf->db_blkptr)
395 395 txh->txh_space_tounref += space;
396 396 }
397 397 }
398 398
399 399 void
400 400 dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len)
401 401 {
402 402 dmu_tx_hold_t *txh;
403 403
404 404 ASSERT(tx->tx_txg == 0);
405 405 ASSERT(len < DMU_MAX_ACCESS);
406 406 ASSERT(len == 0 || UINT64_MAX - off >= len - 1);
407 407
408 408 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
409 409 object, THT_WRITE, off, len);
410 410 if (txh == NULL)
411 411 return;
412 412
413 413 dmu_tx_count_write(txh, off, len);
414 414 dmu_tx_count_dnode(txh);
415 415 }
416 416
417 417 static void
418 418 dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
419 419 {
420 420 uint64_t blkid, nblks, lastblk;
421 421 uint64_t space = 0, unref = 0, skipped = 0;
422 422 dnode_t *dn = txh->txh_dnode;
423 423 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
424 424 spa_t *spa = txh->txh_tx->tx_pool->dp_spa;
425 425 int epbs;
426 426 uint64_t l0span = 0, nl1blks = 0;
427 427
428 428 if (dn->dn_nlevels == 0)
429 429 return;
430 430
431 431 /*
432 432 * The struct_rwlock protects us against dn_nlevels
433 433 * changing, in case (against all odds) we manage to dirty &
434 434 * sync out the changes after we check for being dirty.
435 435 * Also, dbuf_hold_impl() wants us to have the struct_rwlock.
436 436 */
437 437 rw_enter(&dn->dn_struct_rwlock, RW_READER);
438 438 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
439 439 if (dn->dn_maxblkid == 0) {
440 440 if (off == 0 && len >= dn->dn_datablksz) {
441 441 blkid = 0;
442 442 nblks = 1;
443 443 } else {
444 444 rw_exit(&dn->dn_struct_rwlock);
445 445 return;
446 446 }
447 447 } else {
448 448 blkid = off >> dn->dn_datablkshift;
449 449 nblks = (len + dn->dn_datablksz - 1) >> dn->dn_datablkshift;
450 450
451 451 if (blkid >= dn->dn_maxblkid) {
452 452 rw_exit(&dn->dn_struct_rwlock);
453 453 return;
454 454 }
455 455 if (blkid + nblks > dn->dn_maxblkid)
456 456 nblks = dn->dn_maxblkid - blkid;
457 457
458 458 }
459 459 l0span = nblks; /* save for later use to calc level > 1 overhead */
460 460 if (dn->dn_nlevels == 1) {
461 461 int i;
462 462 for (i = 0; i < nblks; i++) {
463 463 blkptr_t *bp = dn->dn_phys->dn_blkptr;
464 464 ASSERT3U(blkid + i, <, dn->dn_nblkptr);
465 465 bp += blkid + i;
466 466 if (dsl_dataset_block_freeable(ds, bp, bp->blk_birth)) {
467 467 dprintf_bp(bp, "can free old%s", "");
468 468 space += bp_get_dsize(spa, bp);
469 469 }
470 470 unref += BP_GET_ASIZE(bp);
471 471 }
472 472 nl1blks = 1;
473 473 nblks = 0;
474 474 }
475 475
476 476 lastblk = blkid + nblks - 1;
477 477 while (nblks) {
478 478 dmu_buf_impl_t *dbuf;
479 479 uint64_t ibyte, new_blkid;
480 480 int epb = 1 << epbs;
481 481 int err, i, blkoff, tochk;
482 482 blkptr_t *bp;
483 483
484 484 ibyte = blkid << dn->dn_datablkshift;
485 485 err = dnode_next_offset(dn,
486 486 DNODE_FIND_HAVELOCK, &ibyte, 2, 1, 0);
487 487 new_blkid = ibyte >> dn->dn_datablkshift;
488 488 if (err == ESRCH) {
489 489 skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
490 490 break;
491 491 }
492 492 if (err) {
493 493 txh->txh_tx->tx_err = err;
494 494 break;
495 495 }
496 496 if (new_blkid > lastblk) {
497 497 skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
498 498 break;
499 499 }
500 500
501 501 if (new_blkid > blkid) {
502 502 ASSERT((new_blkid >> epbs) > (blkid >> epbs));
503 503 skipped += (new_blkid >> epbs) - (blkid >> epbs) - 1;
504 504 nblks -= new_blkid - blkid;
505 505 blkid = new_blkid;
506 506 }
507 507 blkoff = P2PHASE(blkid, epb);
508 508 tochk = MIN(epb - blkoff, nblks);
509 509
510 510 err = dbuf_hold_impl(dn, 1, blkid >> epbs, FALSE, FTAG, &dbuf);
511 511 if (err) {
512 512 txh->txh_tx->tx_err = err;
513 513 break;
514 514 }
515 515
516 516 txh->txh_memory_tohold += dbuf->db.db_size;
517 517
518 518 /*
519 519 * We don't check memory_tohold against DMU_MAX_ACCESS because
520 520 * memory_tohold is an over-estimation (especially the >L1
521 521 * indirect blocks), so it could fail. Callers should have
522 522 * already verified that they will not be holding too much
523 523 * memory.
524 524 */
525 525
526 526 err = dbuf_read(dbuf, NULL, DB_RF_HAVESTRUCT | DB_RF_CANFAIL);
527 527 if (err != 0) {
528 528 txh->txh_tx->tx_err = err;
529 529 dbuf_rele(dbuf, FTAG);
530 530 break;
531 531 }
532 532
533 533 bp = dbuf->db.db_data;
534 534 bp += blkoff;
535 535
536 536 for (i = 0; i < tochk; i++) {
537 537 if (dsl_dataset_block_freeable(ds, &bp[i],
538 538 bp[i].blk_birth)) {
539 539 dprintf_bp(&bp[i], "can free old%s", "");
540 540 space += bp_get_dsize(spa, &bp[i]);
541 541 }
542 542 unref += BP_GET_ASIZE(bp);
543 543 }
544 544 dbuf_rele(dbuf, FTAG);
545 545
546 546 ++nl1blks;
547 547 blkid += tochk;
548 548 nblks -= tochk;
549 549 }
550 550 rw_exit(&dn->dn_struct_rwlock);
551 551
552 552 /*
553 553 * Add in memory requirements of higher-level indirects.
554 554 * This assumes a worst-possible scenario for dn_nlevels and a
555 555 * worst-possible distribution of l1-blocks over the region to free.
556 556 */
557 557 {
558 558 uint64_t blkcnt = 1 + ((l0span >> epbs) >> epbs);
559 559 int level = 2;
560 560 /*
561 561 * Here we don't use DN_MAX_LEVEL, but calculate it with the
562 562 * given datablkshift and indblkshift. This makes the
563 563 * difference between 19 and 8 on large files.
564 564 */
565 565 int maxlevel = 2 + (DN_MAX_OFFSET_SHIFT - dn->dn_datablkshift) /
566 566 (dn->dn_indblkshift - SPA_BLKPTRSHIFT);
567 567
568 568 while (level++ < maxlevel) {
569 569 txh->txh_memory_tohold += MAX(MIN(blkcnt, nl1blks), 1)
570 570 << dn->dn_indblkshift;
571 571 blkcnt = 1 + (blkcnt >> epbs);
572 572 }
573 573 }
574 574
575 575 /* account for new level 1 indirect blocks that might show up */
576 576 if (skipped > 0) {
577 577 txh->txh_fudge += skipped << dn->dn_indblkshift;
578 578 skipped = MIN(skipped, DMU_MAX_DELETEBLKCNT >> epbs);
579 579 txh->txh_memory_tohold += skipped << dn->dn_indblkshift;
580 580 }
581 581 txh->txh_space_tofree += space;
582 582 txh->txh_space_tounref += unref;
583 583 }
584 584
585 585 void
586 586 dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
587 587 {
588 588 dmu_tx_hold_t *txh;
589 589 dnode_t *dn;
590 590 uint64_t start, end, i;
591 591 int err, shift;
592 592 zio_t *zio;
593 593
594 594 ASSERT(tx->tx_txg == 0);
595 595
596 596 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
597 597 object, THT_FREE, off, len);
598 598 if (txh == NULL)
599 599 return;
600 600 dn = txh->txh_dnode;
601 601
602 602 /* first block */
603 603 if (off != 0)
604 604 dmu_tx_count_write(txh, off, 1);
605 605 /* last block */
606 606 if (len != DMU_OBJECT_END)
607 607 dmu_tx_count_write(txh, off+len, 1);
608 608
609 609 dmu_tx_count_dnode(txh);
610 610
611 611 if (off >= (dn->dn_maxblkid+1) * dn->dn_datablksz)
612 612 return;
613 613 if (len == DMU_OBJECT_END)
614 614 len = (dn->dn_maxblkid+1) * dn->dn_datablksz - off;
615 615
616 616 /*
617 617 * For i/o error checking, read the first and last level-0
618 618 * blocks, and all the level-1 blocks. The above count_write's
619 619 * have already taken care of the level-0 blocks.
620 620 */
621 621 if (dn->dn_nlevels > 1) {
622 622 shift = dn->dn_datablkshift + dn->dn_indblkshift -
623 623 SPA_BLKPTRSHIFT;
624 624 start = off >> shift;
625 625 end = dn->dn_datablkshift ? ((off+len) >> shift) : 0;
626 626
627 627 zio = zio_root(tx->tx_pool->dp_spa,
628 628 NULL, NULL, ZIO_FLAG_CANFAIL);
629 629 for (i = start; i <= end; i++) {
630 630 uint64_t ibyte = i << shift;
631 631 err = dnode_next_offset(dn, 0, &ibyte, 2, 1, 0);
632 632 i = ibyte >> shift;
633 633 if (err == ESRCH)
634 634 break;
635 635 if (err) {
636 636 tx->tx_err = err;
637 637 return;
638 638 }
639 639
640 640 err = dmu_tx_check_ioerr(zio, dn, 1, i);
641 641 if (err) {
642 642 tx->tx_err = err;
643 643 return;
644 644 }
645 645 }
646 646 err = zio_wait(zio);
647 647 if (err) {
648 648 tx->tx_err = err;
649 649 return;
650 650 }
651 651 }
652 652
653 653 dmu_tx_count_free(txh, off, len);
654 654 }
655 655
656 656 void
657 657 dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name)
658 658 {
659 659 dmu_tx_hold_t *txh;
660 660 dnode_t *dn;
661 661 uint64_t nblocks;
662 662 int epbs, err;
663 663
664 664 ASSERT(tx->tx_txg == 0);
665 665
666 666 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
667 667 object, THT_ZAP, add, (uintptr_t)name);
668 668 if (txh == NULL)
669 669 return;
670 670 dn = txh->txh_dnode;
671 671
672 672 dmu_tx_count_dnode(txh);
673 673
674 674 if (dn == NULL) {
675 675 /*
676 676 * We will be able to fit a new object's entries into one leaf
677 677 * block. So there will be at most 2 blocks total,
678 678 * including the header block.
679 679 */
680 680 dmu_tx_count_write(txh, 0, 2 << fzap_default_block_shift);
681 681 return;
682 682 }
683 683
684 684 ASSERT3P(DMU_OT_BYTESWAP(dn->dn_type), ==, DMU_BSWAP_ZAP);
685 685
686 686 if (dn->dn_maxblkid == 0 && !add) {
687 687 blkptr_t *bp;
688 688
689 689 /*
690 690 * If there is only one block (i.e. this is a micro-zap)
691 691 * and we are not adding anything, the accounting is simple.
692 692 */
693 693 err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
694 694 if (err) {
695 695 tx->tx_err = err;
696 696 return;
697 697 }
698 698
699 699 /*
700 700 * Use max block size here, since we don't know how much
701 701 * the size will change between now and the dbuf dirty call.
702 702 */
703 703 bp = &dn->dn_phys->dn_blkptr[0];
704 704 if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
705 705 bp, bp->blk_birth))
706 706 txh->txh_space_tooverwrite += SPA_MAXBLOCKSIZE;
707 707 else
708 708 txh->txh_space_towrite += SPA_MAXBLOCKSIZE;
709 709 if (!BP_IS_HOLE(bp))
710 710 txh->txh_space_tounref += SPA_MAXBLOCKSIZE;
711 711 return;
712 712 }
713 713
714 714 if (dn->dn_maxblkid > 0 && name) {
715 715 /*
716 716 * access the name in this fat-zap so that we'll check
717 717 * for i/o errors to the leaf blocks, etc.
718 718 */
719 719 err = zap_lookup(dn->dn_objset, dn->dn_object, name,
720 720 8, 0, NULL);
721 721 if (err == EIO) {
722 722 tx->tx_err = err;
723 723 return;
724 724 }
725 725 }
726 726
727 727 err = zap_count_write(dn->dn_objset, dn->dn_object, name, add,
728 728 &txh->txh_space_towrite, &txh->txh_space_tooverwrite);
729 729
730 730 /*
731 731 * If the modified blocks are scattered to the four winds,
732 732 * we'll have to modify an indirect twig for each.
733 733 */
734 734 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
735 735 for (nblocks = dn->dn_maxblkid >> epbs; nblocks != 0; nblocks >>= epbs)
736 736 if (dn->dn_objset->os_dsl_dataset->ds_phys->ds_prev_snap_obj)
737 737 txh->txh_space_towrite += 3 << dn->dn_indblkshift;
738 738 else
739 739 txh->txh_space_tooverwrite += 3 << dn->dn_indblkshift;
740 740 }
741 741
742 742 void
743 743 dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object)
744 744 {
745 745 dmu_tx_hold_t *txh;
746 746
747 747 ASSERT(tx->tx_txg == 0);
748 748
749 749 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
750 750 object, THT_BONUS, 0, 0);
751 751 if (txh)
752 752 dmu_tx_count_dnode(txh);
753 753 }
754 754
755 755 void
756 756 dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space)
757 757 {
758 758 dmu_tx_hold_t *txh;
759 759 ASSERT(tx->tx_txg == 0);
760 760
761 761 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
762 762 DMU_NEW_OBJECT, THT_SPACE, space, 0);
763 763
764 764 txh->txh_space_towrite += space;
765 765 }
766 766
767 767 int
768 768 dmu_tx_holds(dmu_tx_t *tx, uint64_t object)
769 769 {
770 770 dmu_tx_hold_t *txh;
771 771 int holds = 0;
772 772
773 773 /*
774 774 * By asserting that the tx is assigned, we're counting the
775 775 * number of dn_tx_holds, which is the same as the number of
776 776 * dn_holds. Otherwise, we'd be counting dn_holds, but
777 777 * dn_tx_holds could be 0.
778 778 */
779 779 ASSERT(tx->tx_txg != 0);
780 780
781 781 /* if (tx->tx_anyobj == TRUE) */
782 782 /* return (0); */
783 783
784 784 for (txh = list_head(&tx->tx_holds); txh;
785 785 txh = list_next(&tx->tx_holds, txh)) {
786 786 if (txh->txh_dnode && txh->txh_dnode->dn_object == object)
787 787 holds++;
788 788 }
789 789
790 790 return (holds);
791 791 }
792 792
793 793 #ifdef ZFS_DEBUG
794 794 void
795 795 dmu_tx_dirty_buf(dmu_tx_t *tx, dmu_buf_impl_t *db)
796 796 {
797 797 dmu_tx_hold_t *txh;
798 798 int match_object = FALSE, match_offset = FALSE;
799 799 dnode_t *dn;
800 800
801 801 DB_DNODE_ENTER(db);
802 802 dn = DB_DNODE(db);
803 803 ASSERT(tx->tx_txg != 0);
804 804 ASSERT(tx->tx_objset == NULL || dn->dn_objset == tx->tx_objset);
805 805 ASSERT3U(dn->dn_object, ==, db->db.db_object);
806 806
807 807 if (tx->tx_anyobj) {
808 808 DB_DNODE_EXIT(db);
809 809 return;
810 810 }
811 811
812 812 /* XXX No checking on the meta dnode for now */
813 813 if (db->db.db_object == DMU_META_DNODE_OBJECT) {
814 814 DB_DNODE_EXIT(db);
815 815 return;
816 816 }
817 817
818 818 for (txh = list_head(&tx->tx_holds); txh;
819 819 txh = list_next(&tx->tx_holds, txh)) {
820 820 ASSERT(dn == NULL || dn->dn_assigned_txg == tx->tx_txg);
821 821 if (txh->txh_dnode == dn && txh->txh_type != THT_NEWOBJECT)
822 822 match_object = TRUE;
823 823 if (txh->txh_dnode == NULL || txh->txh_dnode == dn) {
824 824 int datablkshift = dn->dn_datablkshift ?
825 825 dn->dn_datablkshift : SPA_MAXBLOCKSHIFT;
826 826 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
827 827 int shift = datablkshift + epbs * db->db_level;
828 828 uint64_t beginblk = shift >= 64 ? 0 :
829 829 (txh->txh_arg1 >> shift);
830 830 uint64_t endblk = shift >= 64 ? 0 :
831 831 ((txh->txh_arg1 + txh->txh_arg2 - 1) >> shift);
832 832 uint64_t blkid = db->db_blkid;
833 833
834 834 /* XXX txh_arg2 better not be zero... */
835 835
836 836 dprintf("found txh type %x beginblk=%llx endblk=%llx\n",
837 837 txh->txh_type, beginblk, endblk);
838 838
839 839 switch (txh->txh_type) {
840 840 case THT_WRITE:
841 841 if (blkid >= beginblk && blkid <= endblk)
842 842 match_offset = TRUE;
843 843 /*
844 844 * We will let this hold work for the bonus
845 845 * or spill buffer so that we don't need to
846 846 * hold it when creating a new object.
847 847 */
848 848 if (blkid == DMU_BONUS_BLKID ||
849 849 blkid == DMU_SPILL_BLKID)
850 850 match_offset = TRUE;
851 851 /*
852 852 * They might have to increase nlevels,
853 853 * thus dirtying the new TLIBs. Or the
854 854 * might have to change the block size,
855 855 * thus dirying the new lvl=0 blk=0.
856 856 */
857 857 if (blkid == 0)
858 858 match_offset = TRUE;
859 859 break;
860 860 case THT_FREE:
861 861 /*
862 862 * We will dirty all the level 1 blocks in
863 863 * the free range and perhaps the first and
864 864 * last level 0 block.
865 865 */
866 866 if (blkid >= beginblk && (blkid <= endblk ||
867 867 txh->txh_arg2 == DMU_OBJECT_END))
868 868 match_offset = TRUE;
869 869 break;
870 870 case THT_SPILL:
871 871 if (blkid == DMU_SPILL_BLKID)
872 872 match_offset = TRUE;
873 873 break;
874 874 case THT_BONUS:
875 875 if (blkid == DMU_BONUS_BLKID)
876 876 match_offset = TRUE;
877 877 break;
878 878 case THT_ZAP:
879 879 match_offset = TRUE;
880 880 break;
881 881 case THT_NEWOBJECT:
882 882 match_object = TRUE;
883 883 break;
884 884 default:
885 885 ASSERT(!"bad txh_type");
886 886 }
887 887 }
888 888 if (match_object && match_offset) {
889 889 DB_DNODE_EXIT(db);
890 890 return;
891 891 }
892 892 }
893 893 DB_DNODE_EXIT(db);
894 894 panic("dirtying dbuf obj=%llx lvl=%u blkid=%llx but not tx_held\n",
895 895 (u_longlong_t)db->db.db_object, db->db_level,
896 896 (u_longlong_t)db->db_blkid);
897 897 }
898 898 #endif
899 899
900 900 static int
901 901 dmu_tx_try_assign(dmu_tx_t *tx, txg_how_t txg_how)
902 902 {
903 903 dmu_tx_hold_t *txh;
904 904 spa_t *spa = tx->tx_pool->dp_spa;
905 905 uint64_t memory, asize, fsize, usize;
906 906 uint64_t towrite, tofree, tooverwrite, tounref, tohold, fudge;
907 907
908 908 ASSERT0(tx->tx_txg);
909 909
910 910 if (tx->tx_err)
911 911 return (tx->tx_err);
912 912
913 913 if (spa_suspended(spa)) {
914 914 /*
915 915 * If the user has indicated a blocking failure mode
916 916 * then return ERESTART which will block in dmu_tx_wait().
917 917 * Otherwise, return EIO so that an error can get
918 918 * propagated back to the VOP calls.
919 919 *
920 920 * Note that we always honor the txg_how flag regardless
921 921 * of the failuremode setting.
922 922 */
923 923 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_CONTINUE &&
924 924 txg_how != TXG_WAIT)
925 925 return (SET_ERROR(EIO));
926 926
927 927 return (SET_ERROR(ERESTART));
928 928 }
929 929
930 930 tx->tx_txg = txg_hold_open(tx->tx_pool, &tx->tx_txgh);
931 931 tx->tx_needassign_txh = NULL;
932 932
933 933 /*
934 934 * NB: No error returns are allowed after txg_hold_open, but
935 935 * before processing the dnode holds, due to the
936 936 * dmu_tx_unassign() logic.
937 937 */
938 938
939 939 towrite = tofree = tooverwrite = tounref = tohold = fudge = 0;
940 940 for (txh = list_head(&tx->tx_holds); txh;
941 941 txh = list_next(&tx->tx_holds, txh)) {
942 942 dnode_t *dn = txh->txh_dnode;
943 943 if (dn != NULL) {
944 944 mutex_enter(&dn->dn_mtx);
945 945 if (dn->dn_assigned_txg == tx->tx_txg - 1) {
946 946 mutex_exit(&dn->dn_mtx);
947 947 tx->tx_needassign_txh = txh;
948 948 return (SET_ERROR(ERESTART));
949 949 }
950 950 if (dn->dn_assigned_txg == 0)
951 951 dn->dn_assigned_txg = tx->tx_txg;
952 952 ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
953 953 (void) refcount_add(&dn->dn_tx_holds, tx);
954 954 mutex_exit(&dn->dn_mtx);
955 955 }
956 956 towrite += txh->txh_space_towrite;
957 957 tofree += txh->txh_space_tofree;
958 958 tooverwrite += txh->txh_space_tooverwrite;
959 959 tounref += txh->txh_space_tounref;
960 960 tohold += txh->txh_memory_tohold;
961 961 fudge += txh->txh_fudge;
962 962 }
963 963
964 964 /*
965 965 * If a snapshot has been taken since we made our estimates,
966 966 * assume that we won't be able to free or overwrite anything.
967 967 */
968 968 if (tx->tx_objset &&
969 969 dsl_dataset_prev_snap_txg(tx->tx_objset->os_dsl_dataset) >
970 970 tx->tx_lastsnap_txg) {
971 971 towrite += tooverwrite;
972 972 tooverwrite = tofree = 0;
973 973 }
974 974
975 975 /* needed allocation: worst-case estimate of write space */
976 976 asize = spa_get_asize(tx->tx_pool->dp_spa, towrite + tooverwrite);
977 977 /* freed space estimate: worst-case overwrite + free estimate */
978 978 fsize = spa_get_asize(tx->tx_pool->dp_spa, tooverwrite) + tofree;
979 979 /* convert unrefd space to worst-case estimate */
980 980 usize = spa_get_asize(tx->tx_pool->dp_spa, tounref);
981 981 /* calculate memory footprint estimate */
982 982 memory = towrite + tooverwrite + tohold;
983 983
984 984 #ifdef ZFS_DEBUG
985 985 /*
986 986 * Add in 'tohold' to account for our dirty holds on this memory
987 987 * XXX - the "fudge" factor is to account for skipped blocks that
988 988 * we missed because dnode_next_offset() misses in-core-only blocks.
989 989 */
990 990 tx->tx_space_towrite = asize +
991 991 spa_get_asize(tx->tx_pool->dp_spa, tohold + fudge);
992 992 tx->tx_space_tofree = tofree;
993 993 tx->tx_space_tooverwrite = tooverwrite;
994 994 tx->tx_space_tounref = tounref;
995 995 #endif
996 996
997 997 if (tx->tx_dir && asize != 0) {
998 998 int err = dsl_dir_tempreserve_space(tx->tx_dir, memory,
999 999 asize, fsize, usize, &tx->tx_tempreserve_cookie, tx);
1000 1000 if (err)
1001 1001 return (err);
1002 1002 }
1003 1003
1004 1004 return (0);
1005 1005 }
1006 1006
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1007 1007 static void
1008 1008 dmu_tx_unassign(dmu_tx_t *tx)
1009 1009 {
1010 1010 dmu_tx_hold_t *txh;
1011 1011
1012 1012 if (tx->tx_txg == 0)
1013 1013 return;
1014 1014
1015 1015 txg_rele_to_quiesce(&tx->tx_txgh);
1016 1016
1017 + /*
1018 + * Walk the transaction's hold list, removing the hold on the
1019 + * associated dnode, and notifying waiters if the refcount drops to 0.
1020 + */
1017 1021 for (txh = list_head(&tx->tx_holds); txh != tx->tx_needassign_txh;
1018 1022 txh = list_next(&tx->tx_holds, txh)) {
1019 1023 dnode_t *dn = txh->txh_dnode;
1020 1024
1021 1025 if (dn == NULL)
1022 1026 continue;
1023 1027 mutex_enter(&dn->dn_mtx);
1024 1028 ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
1025 1029
1026 1030 if (refcount_remove(&dn->dn_tx_holds, tx) == 0) {
1027 1031 dn->dn_assigned_txg = 0;
1028 1032 cv_broadcast(&dn->dn_notxholds);
1029 1033 }
1030 1034 mutex_exit(&dn->dn_mtx);
1031 1035 }
1032 1036
1033 1037 txg_rele_to_sync(&tx->tx_txgh);
1034 1038
1035 1039 tx->tx_lasttried_txg = tx->tx_txg;
1036 1040 tx->tx_txg = 0;
1037 1041 }
1038 1042
1039 1043 /*
1040 1044 * Assign tx to a transaction group. txg_how can be one of:
1041 1045 *
1042 1046 * (1) TXG_WAIT. If the current open txg is full, waits until there's
1043 1047 * a new one. This should be used when you're not holding locks.
1044 1048 * It will only fail if we're truly out of space (or over quota).
1045 1049 *
1046 1050 * (2) TXG_NOWAIT. If we can't assign into the current open txg without
1047 1051 * blocking, returns immediately with ERESTART. This should be used
1048 1052 * whenever you're holding locks. On an ERESTART error, the caller
1049 1053 * should drop locks, do a dmu_tx_wait(tx), and try again.
1050 1054 */
1051 1055 int
1052 1056 dmu_tx_assign(dmu_tx_t *tx, txg_how_t txg_how)
1053 1057 {
1054 1058 int err;
1055 1059
1056 1060 ASSERT(tx->tx_txg == 0);
1057 1061 ASSERT(txg_how == TXG_WAIT || txg_how == TXG_NOWAIT);
1058 1062 ASSERT(!dsl_pool_sync_context(tx->tx_pool));
1059 1063
1060 1064 /* If we might wait, we must not hold the config lock. */
1061 1065 ASSERT(txg_how != TXG_WAIT || !dsl_pool_config_held(tx->tx_pool));
1062 1066
1063 1067 while ((err = dmu_tx_try_assign(tx, txg_how)) != 0) {
1064 1068 dmu_tx_unassign(tx);
1065 1069
1066 1070 if (err != ERESTART || txg_how != TXG_WAIT)
1067 1071 return (err);
1068 1072
1069 1073 dmu_tx_wait(tx);
1070 1074 }
1071 1075
1072 1076 txg_rele_to_quiesce(&tx->tx_txgh);
1073 1077
1074 1078 return (0);
1075 1079 }
1076 1080
1077 1081 void
1078 1082 dmu_tx_wait(dmu_tx_t *tx)
1079 1083 {
1080 1084 spa_t *spa = tx->tx_pool->dp_spa;
1081 1085
1082 1086 ASSERT(tx->tx_txg == 0);
1083 1087 ASSERT(!dsl_pool_config_held(tx->tx_pool));
1084 1088
1085 1089 /*
1086 1090 * It's possible that the pool has become active after this thread
1087 1091 * has tried to obtain a tx. If that's the case then his
1088 1092 * tx_lasttried_txg would not have been assigned.
1089 1093 */
1090 1094 if (spa_suspended(spa) || tx->tx_lasttried_txg == 0) {
1091 1095 txg_wait_synced(tx->tx_pool, spa_last_synced_txg(spa) + 1);
1092 1096 } else if (tx->tx_needassign_txh) {
1093 1097 dnode_t *dn = tx->tx_needassign_txh->txh_dnode;
1094 1098
1095 1099 mutex_enter(&dn->dn_mtx);
1096 1100 while (dn->dn_assigned_txg == tx->tx_lasttried_txg - 1)
1097 1101 cv_wait(&dn->dn_notxholds, &dn->dn_mtx);
1098 1102 mutex_exit(&dn->dn_mtx);
1099 1103 tx->tx_needassign_txh = NULL;
1100 1104 } else {
1101 1105 txg_wait_open(tx->tx_pool, tx->tx_lasttried_txg + 1);
1102 1106 }
1103 1107 }
1104 1108
1105 1109 void
1106 1110 dmu_tx_willuse_space(dmu_tx_t *tx, int64_t delta)
1107 1111 {
1108 1112 #ifdef ZFS_DEBUG
1109 1113 if (tx->tx_dir == NULL || delta == 0)
1110 1114 return;
1111 1115
1112 1116 if (delta > 0) {
1113 1117 ASSERT3U(refcount_count(&tx->tx_space_written) + delta, <=,
1114 1118 tx->tx_space_towrite);
1115 1119 (void) refcount_add_many(&tx->tx_space_written, delta, NULL);
1116 1120 } else {
1117 1121 (void) refcount_add_many(&tx->tx_space_freed, -delta, NULL);
1118 1122 }
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1119 1123 #endif
1120 1124 }
1121 1125
1122 1126 void
1123 1127 dmu_tx_commit(dmu_tx_t *tx)
1124 1128 {
1125 1129 dmu_tx_hold_t *txh;
1126 1130
1127 1131 ASSERT(tx->tx_txg != 0);
1128 1132
1133 + /*
1134 + * Go through the transaction's hold list and remove holds on
1135 + * associated dnodes, notifying waiters if no holds remain.
1136 + */
1129 1137 while (txh = list_head(&tx->tx_holds)) {
1130 1138 dnode_t *dn = txh->txh_dnode;
1131 1139
1132 1140 list_remove(&tx->tx_holds, txh);
1133 1141 kmem_free(txh, sizeof (dmu_tx_hold_t));
1134 1142 if (dn == NULL)
1135 1143 continue;
1136 1144 mutex_enter(&dn->dn_mtx);
1137 1145 ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
1138 1146
1139 1147 if (refcount_remove(&dn->dn_tx_holds, tx) == 0) {
1140 1148 dn->dn_assigned_txg = 0;
1141 1149 cv_broadcast(&dn->dn_notxholds);
1142 1150 }
1143 1151 mutex_exit(&dn->dn_mtx);
1144 1152 dnode_rele(dn, tx);
1145 1153 }
1146 1154
1147 1155 if (tx->tx_tempreserve_cookie)
1148 1156 dsl_dir_tempreserve_clear(tx->tx_tempreserve_cookie, tx);
1149 1157
1150 1158 if (!list_is_empty(&tx->tx_callbacks))
1151 1159 txg_register_callbacks(&tx->tx_txgh, &tx->tx_callbacks);
1152 1160
1153 1161 if (tx->tx_anyobj == FALSE)
1154 1162 txg_rele_to_sync(&tx->tx_txgh);
1155 1163
1156 1164 list_destroy(&tx->tx_callbacks);
1157 1165 list_destroy(&tx->tx_holds);
1158 1166 #ifdef ZFS_DEBUG
1159 1167 dprintf("towrite=%llu written=%llu tofree=%llu freed=%llu\n",
1160 1168 tx->tx_space_towrite, refcount_count(&tx->tx_space_written),
1161 1169 tx->tx_space_tofree, refcount_count(&tx->tx_space_freed));
1162 1170 refcount_destroy_many(&tx->tx_space_written,
1163 1171 refcount_count(&tx->tx_space_written));
1164 1172 refcount_destroy_many(&tx->tx_space_freed,
1165 1173 refcount_count(&tx->tx_space_freed));
1166 1174 #endif
1167 1175 kmem_free(tx, sizeof (dmu_tx_t));
1168 1176 }
1169 1177
1170 1178 void
1171 1179 dmu_tx_abort(dmu_tx_t *tx)
1172 1180 {
1173 1181 dmu_tx_hold_t *txh;
1174 1182
1175 1183 ASSERT(tx->tx_txg == 0);
1176 1184
1177 1185 while (txh = list_head(&tx->tx_holds)) {
1178 1186 dnode_t *dn = txh->txh_dnode;
1179 1187
1180 1188 list_remove(&tx->tx_holds, txh);
1181 1189 kmem_free(txh, sizeof (dmu_tx_hold_t));
1182 1190 if (dn != NULL)
1183 1191 dnode_rele(dn, tx);
1184 1192 }
1185 1193
1186 1194 /*
1187 1195 * Call any registered callbacks with an error code.
1188 1196 */
1189 1197 if (!list_is_empty(&tx->tx_callbacks))
1190 1198 dmu_tx_do_callbacks(&tx->tx_callbacks, ECANCELED);
1191 1199
1192 1200 list_destroy(&tx->tx_callbacks);
1193 1201 list_destroy(&tx->tx_holds);
1194 1202 #ifdef ZFS_DEBUG
1195 1203 refcount_destroy_many(&tx->tx_space_written,
1196 1204 refcount_count(&tx->tx_space_written));
1197 1205 refcount_destroy_many(&tx->tx_space_freed,
1198 1206 refcount_count(&tx->tx_space_freed));
1199 1207 #endif
1200 1208 kmem_free(tx, sizeof (dmu_tx_t));
1201 1209 }
1202 1210
1203 1211 uint64_t
1204 1212 dmu_tx_get_txg(dmu_tx_t *tx)
1205 1213 {
1206 1214 ASSERT(tx->tx_txg != 0);
1207 1215 return (tx->tx_txg);
1208 1216 }
1209 1217
1210 1218 dsl_pool_t *
1211 1219 dmu_tx_pool(dmu_tx_t *tx)
1212 1220 {
1213 1221 ASSERT(tx->tx_pool != NULL);
1214 1222 return (tx->tx_pool);
1215 1223 }
1216 1224
1217 1225
1218 1226 void
1219 1227 dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *func, void *data)
1220 1228 {
1221 1229 dmu_tx_callback_t *dcb;
1222 1230
1223 1231 dcb = kmem_alloc(sizeof (dmu_tx_callback_t), KM_SLEEP);
1224 1232
1225 1233 dcb->dcb_func = func;
1226 1234 dcb->dcb_data = data;
1227 1235
1228 1236 list_insert_tail(&tx->tx_callbacks, dcb);
1229 1237 }
1230 1238
1231 1239 /*
1232 1240 * Call all the commit callbacks on a list, with a given error code.
1233 1241 */
1234 1242 void
1235 1243 dmu_tx_do_callbacks(list_t *cb_list, int error)
1236 1244 {
1237 1245 dmu_tx_callback_t *dcb;
1238 1246
1239 1247 while (dcb = list_head(cb_list)) {
1240 1248 list_remove(cb_list, dcb);
1241 1249 dcb->dcb_func(dcb->dcb_data, error);
1242 1250 kmem_free(dcb, sizeof (dmu_tx_callback_t));
1243 1251 }
1244 1252 }
1245 1253
1246 1254 /*
1247 1255 * Interface to hold a bunch of attributes.
1248 1256 * used for creating new files.
1249 1257 * attrsize is the total size of all attributes
1250 1258 * to be added during object creation
1251 1259 *
1252 1260 * For updating/adding a single attribute dmu_tx_hold_sa() should be used.
1253 1261 */
1254 1262
1255 1263 /*
1256 1264 * hold necessary attribute name for attribute registration.
1257 1265 * should be a very rare case where this is needed. If it does
1258 1266 * happen it would only happen on the first write to the file system.
1259 1267 */
1260 1268 static void
1261 1269 dmu_tx_sa_registration_hold(sa_os_t *sa, dmu_tx_t *tx)
1262 1270 {
1263 1271 int i;
1264 1272
1265 1273 if (!sa->sa_need_attr_registration)
1266 1274 return;
1267 1275
1268 1276 for (i = 0; i != sa->sa_num_attrs; i++) {
1269 1277 if (!sa->sa_attr_table[i].sa_registered) {
1270 1278 if (sa->sa_reg_attr_obj)
1271 1279 dmu_tx_hold_zap(tx, sa->sa_reg_attr_obj,
1272 1280 B_TRUE, sa->sa_attr_table[i].sa_name);
1273 1281 else
1274 1282 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT,
1275 1283 B_TRUE, sa->sa_attr_table[i].sa_name);
1276 1284 }
1277 1285 }
1278 1286 }
1279 1287
1280 1288
1281 1289 void
1282 1290 dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object)
1283 1291 {
1284 1292 dnode_t *dn;
1285 1293 dmu_tx_hold_t *txh;
1286 1294
1287 1295 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, object,
1288 1296 THT_SPILL, 0, 0);
1289 1297
1290 1298 dn = txh->txh_dnode;
1291 1299
1292 1300 if (dn == NULL)
1293 1301 return;
1294 1302
1295 1303 /* If blkptr doesn't exist then add space to towrite */
1296 1304 if (!(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) {
1297 1305 txh->txh_space_towrite += SPA_MAXBLOCKSIZE;
1298 1306 } else {
1299 1307 blkptr_t *bp;
1300 1308
1301 1309 bp = &dn->dn_phys->dn_spill;
1302 1310 if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
1303 1311 bp, bp->blk_birth))
1304 1312 txh->txh_space_tooverwrite += SPA_MAXBLOCKSIZE;
1305 1313 else
1306 1314 txh->txh_space_towrite += SPA_MAXBLOCKSIZE;
1307 1315 if (!BP_IS_HOLE(bp))
1308 1316 txh->txh_space_tounref += SPA_MAXBLOCKSIZE;
1309 1317 }
1310 1318 }
1311 1319
1312 1320 void
1313 1321 dmu_tx_hold_sa_create(dmu_tx_t *tx, int attrsize)
1314 1322 {
1315 1323 sa_os_t *sa = tx->tx_objset->os_sa;
1316 1324
1317 1325 dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
1318 1326
1319 1327 if (tx->tx_objset->os_sa->sa_master_obj == 0)
1320 1328 return;
1321 1329
1322 1330 if (tx->tx_objset->os_sa->sa_layout_attr_obj)
1323 1331 dmu_tx_hold_zap(tx, sa->sa_layout_attr_obj, B_TRUE, NULL);
1324 1332 else {
1325 1333 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_LAYOUTS);
1326 1334 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_REGISTRY);
1327 1335 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1328 1336 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1329 1337 }
1330 1338
1331 1339 dmu_tx_sa_registration_hold(sa, tx);
1332 1340
1333 1341 if (attrsize <= DN_MAX_BONUSLEN && !sa->sa_force_spill)
1334 1342 return;
1335 1343
1336 1344 (void) dmu_tx_hold_object_impl(tx, tx->tx_objset, DMU_NEW_OBJECT,
1337 1345 THT_SPILL, 0, 0);
1338 1346 }
1339 1347
1340 1348 /*
1341 1349 * Hold SA attribute
1342 1350 *
1343 1351 * dmu_tx_hold_sa(dmu_tx_t *tx, sa_handle_t *, attribute, add, size)
1344 1352 *
1345 1353 * variable_size is the total size of all variable sized attributes
1346 1354 * passed to this function. It is not the total size of all
1347 1355 * variable size attributes that *may* exist on this object.
1348 1356 */
1349 1357 void
1350 1358 dmu_tx_hold_sa(dmu_tx_t *tx, sa_handle_t *hdl, boolean_t may_grow)
1351 1359 {
1352 1360 uint64_t object;
1353 1361 sa_os_t *sa = tx->tx_objset->os_sa;
1354 1362
1355 1363 ASSERT(hdl != NULL);
1356 1364
1357 1365 object = sa_handle_object(hdl);
1358 1366
1359 1367 dmu_tx_hold_bonus(tx, object);
1360 1368
1361 1369 if (tx->tx_objset->os_sa->sa_master_obj == 0)
1362 1370 return;
1363 1371
1364 1372 if (tx->tx_objset->os_sa->sa_reg_attr_obj == 0 ||
1365 1373 tx->tx_objset->os_sa->sa_layout_attr_obj == 0) {
1366 1374 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_LAYOUTS);
1367 1375 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_REGISTRY);
1368 1376 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1369 1377 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1370 1378 }
1371 1379
1372 1380 dmu_tx_sa_registration_hold(sa, tx);
1373 1381
1374 1382 if (may_grow && tx->tx_objset->os_sa->sa_layout_attr_obj)
1375 1383 dmu_tx_hold_zap(tx, sa->sa_layout_attr_obj, B_TRUE, NULL);
1376 1384
1377 1385 if (sa->sa_force_spill || may_grow || hdl->sa_spill) {
1378 1386 ASSERT(tx->tx_txg == 0);
1379 1387 dmu_tx_hold_spill(tx, object);
1380 1388 } else {
1381 1389 dmu_buf_impl_t *db = (dmu_buf_impl_t *)hdl->sa_bonus;
1382 1390 dnode_t *dn;
1383 1391
1384 1392 DB_DNODE_ENTER(db);
1385 1393 dn = DB_DNODE(db);
1386 1394 if (dn->dn_have_spill) {
1387 1395 ASSERT(tx->tx_txg == 0);
1388 1396 dmu_tx_hold_spill(tx, object);
1389 1397 }
1390 1398 DB_DNODE_EXIT(db);
1391 1399 }
1392 1400 }
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