1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
25 */
26
27 #include <sys/dmu.h>
28 #include <sys/dmu_impl.h>
29 #include <sys/dbuf.h>
30 #include <sys/dmu_tx.h>
31 #include <sys/dmu_objset.h>
32 #include <sys/dsl_dataset.h> /* for dsl_dataset_block_freeable() */
33 #include <sys/dsl_dir.h> /* for dsl_dir_tempreserve_*() */
34 #include <sys/dsl_pool.h>
35 #include <sys/zap_impl.h> /* for fzap_default_block_shift */
36 #include <sys/spa.h>
37 #include <sys/sa.h>
38 #include <sys/sa_impl.h>
39 #include <sys/zfs_context.h>
40 #include <sys/varargs.h>
41
42 typedef void (*dmu_tx_hold_func_t)(dmu_tx_t *tx, struct dnode *dn,
43 uint64_t arg1, uint64_t arg2);
44
45
46 dmu_tx_t *
dmu_tx_create_dd(dsl_dir_t * dd)47 dmu_tx_create_dd(dsl_dir_t *dd)
48 {
49 dmu_tx_t *tx = kmem_zalloc(sizeof (dmu_tx_t), KM_SLEEP);
50 tx->tx_dir = dd;
51 if (dd != NULL)
52 tx->tx_pool = dd->dd_pool;
53 list_create(&tx->tx_holds, sizeof (dmu_tx_hold_t),
54 offsetof(dmu_tx_hold_t, txh_node));
55 list_create(&tx->tx_callbacks, sizeof (dmu_tx_callback_t),
56 offsetof(dmu_tx_callback_t, dcb_node));
57 tx->tx_start = gethrtime();
58 #ifdef ZFS_DEBUG
59 refcount_create(&tx->tx_space_written);
60 refcount_create(&tx->tx_space_freed);
61 #endif
62 return (tx);
63 }
64
65 dmu_tx_t *
dmu_tx_create(objset_t * os)66 dmu_tx_create(objset_t *os)
67 {
68 dmu_tx_t *tx = dmu_tx_create_dd(os->os_dsl_dataset->ds_dir);
69 tx->tx_objset = os;
70 tx->tx_lastsnap_txg = dsl_dataset_prev_snap_txg(os->os_dsl_dataset);
71 return (tx);
72 }
73
74 dmu_tx_t *
dmu_tx_create_assigned(struct dsl_pool * dp,uint64_t txg)75 dmu_tx_create_assigned(struct dsl_pool *dp, uint64_t txg)
76 {
77 dmu_tx_t *tx = dmu_tx_create_dd(NULL);
78
79 ASSERT3U(txg, <=, dp->dp_tx.tx_open_txg);
80 tx->tx_pool = dp;
81 tx->tx_txg = txg;
82 tx->tx_anyobj = TRUE;
83
84 return (tx);
85 }
86
87 int
dmu_tx_is_syncing(dmu_tx_t * tx)88 dmu_tx_is_syncing(dmu_tx_t *tx)
89 {
90 return (tx->tx_anyobj);
91 }
92
93 int
dmu_tx_private_ok(dmu_tx_t * tx)94 dmu_tx_private_ok(dmu_tx_t *tx)
95 {
96 return (tx->tx_anyobj);
97 }
98
99 static dmu_tx_hold_t *
dmu_tx_hold_object_impl(dmu_tx_t * tx,objset_t * os,uint64_t object,enum dmu_tx_hold_type type,uint64_t arg1,uint64_t arg2)100 dmu_tx_hold_object_impl(dmu_tx_t *tx, objset_t *os, uint64_t object,
101 enum dmu_tx_hold_type type, uint64_t arg1, uint64_t arg2)
102 {
103 dmu_tx_hold_t *txh;
104 dnode_t *dn = NULL;
105 int err;
106
107 if (object != DMU_NEW_OBJECT) {
108 err = dnode_hold(os, object, tx, &dn);
109 if (err) {
110 tx->tx_err = err;
111 return (NULL);
112 }
113
114 if (err == 0 && tx->tx_txg != 0) {
115 mutex_enter(&dn->dn_mtx);
116 /*
117 * dn->dn_assigned_txg == tx->tx_txg doesn't pose a
118 * problem, but there's no way for it to happen (for
119 * now, at least).
120 */
121 ASSERT(dn->dn_assigned_txg == 0);
122 dn->dn_assigned_txg = tx->tx_txg;
123 (void) refcount_add(&dn->dn_tx_holds, tx);
124 mutex_exit(&dn->dn_mtx);
125 }
126 }
127
128 txh = kmem_zalloc(sizeof (dmu_tx_hold_t), KM_SLEEP);
129 txh->txh_tx = tx;
130 txh->txh_dnode = dn;
131 #ifdef ZFS_DEBUG
132 txh->txh_type = type;
133 txh->txh_arg1 = arg1;
134 txh->txh_arg2 = arg2;
135 #endif
136 list_insert_tail(&tx->tx_holds, txh);
137
138 return (txh);
139 }
140
141 void
dmu_tx_add_new_object(dmu_tx_t * tx,objset_t * os,uint64_t object)142 dmu_tx_add_new_object(dmu_tx_t *tx, objset_t *os, uint64_t object)
143 {
144 /*
145 * If we're syncing, they can manipulate any object anyhow, and
146 * the hold on the dnode_t can cause problems.
147 */
148 if (!dmu_tx_is_syncing(tx)) {
149 (void) dmu_tx_hold_object_impl(tx, os,
150 object, THT_NEWOBJECT, 0, 0);
151 }
152 }
153
154 static int
dmu_tx_check_ioerr(zio_t * zio,dnode_t * dn,int level,uint64_t blkid)155 dmu_tx_check_ioerr(zio_t *zio, dnode_t *dn, int level, uint64_t blkid)
156 {
157 int err;
158 dmu_buf_impl_t *db;
159
160 rw_enter(&dn->dn_struct_rwlock, RW_READER);
161 db = dbuf_hold_level(dn, level, blkid, FTAG);
162 rw_exit(&dn->dn_struct_rwlock);
163 if (db == NULL)
164 return (SET_ERROR(EIO));
165 err = dbuf_read(db, zio, DB_RF_CANFAIL | DB_RF_NOPREFETCH);
166 dbuf_rele(db, FTAG);
167 return (err);
168 }
169
170 static void
dmu_tx_count_twig(dmu_tx_hold_t * txh,dnode_t * dn,dmu_buf_impl_t * db,int level,uint64_t blkid,boolean_t freeable,uint64_t * history)171 dmu_tx_count_twig(dmu_tx_hold_t *txh, dnode_t *dn, dmu_buf_impl_t *db,
172 int level, uint64_t blkid, boolean_t freeable, uint64_t *history)
173 {
174 objset_t *os = dn->dn_objset;
175 dsl_dataset_t *ds = os->os_dsl_dataset;
176 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
177 dmu_buf_impl_t *parent = NULL;
178 blkptr_t *bp = NULL;
179 uint64_t space;
180
181 if (level >= dn->dn_nlevels || history[level] == blkid)
182 return;
183
184 history[level] = blkid;
185
186 space = (level == 0) ? dn->dn_datablksz : (1ULL << dn->dn_indblkshift);
187
188 if (db == NULL || db == dn->dn_dbuf) {
189 ASSERT(level != 0);
190 db = NULL;
191 } else {
192 ASSERT(DB_DNODE(db) == dn);
193 ASSERT(db->db_level == level);
194 ASSERT(db->db.db_size == space);
195 ASSERT(db->db_blkid == blkid);
196 bp = db->db_blkptr;
197 parent = db->db_parent;
198 }
199
200 freeable = (bp && (freeable ||
201 dsl_dataset_block_freeable(ds, bp, bp->blk_birth)));
202
203 if (freeable)
204 txh->txh_space_tooverwrite += space;
205 else
206 txh->txh_space_towrite += space;
207 if (bp)
208 txh->txh_space_tounref += bp_get_dsize(os->os_spa, bp);
209
210 dmu_tx_count_twig(txh, dn, parent, level + 1,
211 blkid >> epbs, freeable, history);
212 }
213
214 /* ARGSUSED */
215 static void
dmu_tx_count_write(dmu_tx_hold_t * txh,uint64_t off,uint64_t len)216 dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
217 {
218 dnode_t *dn = txh->txh_dnode;
219 uint64_t start, end, i;
220 int min_bs, max_bs, min_ibs, max_ibs, epbs, bits;
221 int err = 0;
222
223 if (len == 0)
224 return;
225
226 min_bs = SPA_MINBLOCKSHIFT;
227 max_bs = highbit64(txh->txh_tx->tx_objset->os_recordsize) - 1;
228 min_ibs = DN_MIN_INDBLKSHIFT;
229 max_ibs = DN_MAX_INDBLKSHIFT;
230
231 if (dn) {
232 uint64_t history[DN_MAX_LEVELS];
233 int nlvls = dn->dn_nlevels;
234 int delta;
235
236 /*
237 * For i/o error checking, read the first and last level-0
238 * blocks (if they are not aligned), and all the level-1 blocks.
239 */
240 if (dn->dn_maxblkid == 0) {
241 delta = dn->dn_datablksz;
242 start = (off < dn->dn_datablksz) ? 0 : 1;
243 end = (off+len <= dn->dn_datablksz) ? 0 : 1;
244 if (start == 0 && (off > 0 || len < dn->dn_datablksz)) {
245 err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
246 if (err)
247 goto out;
248 delta -= off;
249 }
250 } else {
251 zio_t *zio = zio_root(dn->dn_objset->os_spa,
252 NULL, NULL, ZIO_FLAG_CANFAIL);
253
254 /* first level-0 block */
255 start = off >> dn->dn_datablkshift;
256 if (P2PHASE(off, dn->dn_datablksz) ||
257 len < dn->dn_datablksz) {
258 err = dmu_tx_check_ioerr(zio, dn, 0, start);
259 if (err)
260 goto out;
261 }
262
263 /* last level-0 block */
264 end = (off+len-1) >> dn->dn_datablkshift;
265 if (end != start && end <= dn->dn_maxblkid &&
266 P2PHASE(off+len, dn->dn_datablksz)) {
267 err = dmu_tx_check_ioerr(zio, dn, 0, end);
268 if (err)
269 goto out;
270 }
271
272 /* level-1 blocks */
273 if (nlvls > 1) {
274 int shft = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
275 for (i = (start>>shft)+1; i < end>>shft; i++) {
276 err = dmu_tx_check_ioerr(zio, dn, 1, i);
277 if (err)
278 goto out;
279 }
280 }
281
282 err = zio_wait(zio);
283 if (err)
284 goto out;
285 delta = P2NPHASE(off, dn->dn_datablksz);
286 }
287
288 min_ibs = max_ibs = dn->dn_indblkshift;
289 if (dn->dn_maxblkid > 0) {
290 /*
291 * The blocksize can't change,
292 * so we can make a more precise estimate.
293 */
294 ASSERT(dn->dn_datablkshift != 0);
295 min_bs = max_bs = dn->dn_datablkshift;
296 } else {
297 /*
298 * The blocksize can increase up to the recordsize,
299 * or if it is already more than the recordsize,
300 * up to the next power of 2.
301 */
302 min_bs = highbit64(dn->dn_datablksz - 1);
303 max_bs = MAX(max_bs, highbit64(dn->dn_datablksz - 1));
304 }
305
306 /*
307 * If this write is not off the end of the file
308 * we need to account for overwrites/unref.
309 */
310 if (start <= dn->dn_maxblkid) {
311 for (int l = 0; l < DN_MAX_LEVELS; l++)
312 history[l] = -1ULL;
313 }
314 while (start <= dn->dn_maxblkid) {
315 dmu_buf_impl_t *db;
316
317 rw_enter(&dn->dn_struct_rwlock, RW_READER);
318 err = dbuf_hold_impl(dn, 0, start, FALSE, FTAG, &db);
319 rw_exit(&dn->dn_struct_rwlock);
320
321 if (err) {
322 txh->txh_tx->tx_err = err;
323 return;
324 }
325
326 dmu_tx_count_twig(txh, dn, db, 0, start, B_FALSE,
327 history);
328 dbuf_rele(db, FTAG);
329 if (++start > end) {
330 /*
331 * Account for new indirects appearing
332 * before this IO gets assigned into a txg.
333 */
334 bits = 64 - min_bs;
335 epbs = min_ibs - SPA_BLKPTRSHIFT;
336 for (bits -= epbs * (nlvls - 1);
337 bits >= 0; bits -= epbs)
338 txh->txh_fudge += 1ULL << max_ibs;
339 goto out;
340 }
341 off += delta;
342 if (len >= delta)
343 len -= delta;
344 delta = dn->dn_datablksz;
345 }
346 }
347
348 /*
349 * 'end' is the last thing we will access, not one past.
350 * This way we won't overflow when accessing the last byte.
351 */
352 start = P2ALIGN(off, 1ULL << max_bs);
353 end = P2ROUNDUP(off + len, 1ULL << max_bs) - 1;
354 txh->txh_space_towrite += end - start + 1;
355
356 start >>= min_bs;
357 end >>= min_bs;
358
359 epbs = min_ibs - SPA_BLKPTRSHIFT;
360
361 /*
362 * The object contains at most 2^(64 - min_bs) blocks,
363 * and each indirect level maps 2^epbs.
364 */
365 for (bits = 64 - min_bs; bits >= 0; bits -= epbs) {
366 start >>= epbs;
367 end >>= epbs;
368 ASSERT3U(end, >=, start);
369 txh->txh_space_towrite += (end - start + 1) << max_ibs;
370 if (start != 0) {
371 /*
372 * We also need a new blkid=0 indirect block
373 * to reference any existing file data.
374 */
375 txh->txh_space_towrite += 1ULL << max_ibs;
376 }
377 }
378
379 out:
380 if (txh->txh_space_towrite + txh->txh_space_tooverwrite >
381 2 * DMU_MAX_ACCESS)
382 err = SET_ERROR(EFBIG);
383
384 if (err)
385 txh->txh_tx->tx_err = err;
386 }
387
388 static void
dmu_tx_count_dnode(dmu_tx_hold_t * txh)389 dmu_tx_count_dnode(dmu_tx_hold_t *txh)
390 {
391 dnode_t *dn = txh->txh_dnode;
392 dnode_t *mdn = DMU_META_DNODE(txh->txh_tx->tx_objset);
393 uint64_t space = mdn->dn_datablksz +
394 ((mdn->dn_nlevels-1) << mdn->dn_indblkshift);
395
396 if (dn && dn->dn_dbuf->db_blkptr &&
397 dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
398 dn->dn_dbuf->db_blkptr, dn->dn_dbuf->db_blkptr->blk_birth)) {
399 txh->txh_space_tooverwrite += space;
400 txh->txh_space_tounref += space;
401 } else {
402 txh->txh_space_towrite += space;
403 if (dn && dn->dn_dbuf->db_blkptr)
404 txh->txh_space_tounref += space;
405 }
406 }
407
408 void
dmu_tx_hold_write(dmu_tx_t * tx,uint64_t object,uint64_t off,int len)409 dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len)
410 {
411 dmu_tx_hold_t *txh;
412
413 ASSERT(tx->tx_txg == 0);
414 ASSERT(len < DMU_MAX_ACCESS);
415 ASSERT(len == 0 || UINT64_MAX - off >= len - 1);
416
417 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
418 object, THT_WRITE, off, len);
419 if (txh == NULL)
420 return;
421
422 dmu_tx_count_write(txh, off, len);
423 dmu_tx_count_dnode(txh);
424 }
425
426 static void
dmu_tx_count_free(dmu_tx_hold_t * txh,uint64_t off,uint64_t len)427 dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
428 {
429 uint64_t blkid, nblks, lastblk;
430 uint64_t space = 0, unref = 0, skipped = 0;
431 dnode_t *dn = txh->txh_dnode;
432 dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
433 spa_t *spa = txh->txh_tx->tx_pool->dp_spa;
434 int epbs;
435 uint64_t l0span = 0, nl1blks = 0;
436
437 if (dn->dn_nlevels == 0)
438 return;
439
440 /*
441 * The struct_rwlock protects us against dn_nlevels
442 * changing, in case (against all odds) we manage to dirty &
443 * sync out the changes after we check for being dirty.
444 * Also, dbuf_hold_impl() wants us to have the struct_rwlock.
445 */
446 rw_enter(&dn->dn_struct_rwlock, RW_READER);
447 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
448 if (dn->dn_maxblkid == 0) {
449 if (off == 0 && len >= dn->dn_datablksz) {
450 blkid = 0;
451 nblks = 1;
452 } else {
453 rw_exit(&dn->dn_struct_rwlock);
454 return;
455 }
456 } else {
457 blkid = off >> dn->dn_datablkshift;
458 nblks = (len + dn->dn_datablksz - 1) >> dn->dn_datablkshift;
459
460 if (blkid > dn->dn_maxblkid) {
461 rw_exit(&dn->dn_struct_rwlock);
462 return;
463 }
464 if (blkid + nblks > dn->dn_maxblkid)
465 nblks = dn->dn_maxblkid - blkid + 1;
466
467 }
468 l0span = nblks; /* save for later use to calc level > 1 overhead */
469 if (dn->dn_nlevels == 1) {
470 int i;
471 for (i = 0; i < nblks; i++) {
472 blkptr_t *bp = dn->dn_phys->dn_blkptr;
473 ASSERT3U(blkid + i, <, dn->dn_nblkptr);
474 bp += blkid + i;
475 if (dsl_dataset_block_freeable(ds, bp, bp->blk_birth)) {
476 dprintf_bp(bp, "can free old%s", "");
477 space += bp_get_dsize(spa, bp);
478 }
479 unref += BP_GET_ASIZE(bp);
480 }
481 nl1blks = 1;
482 nblks = 0;
483 }
484
485 lastblk = blkid + nblks - 1;
486 while (nblks) {
487 dmu_buf_impl_t *dbuf;
488 uint64_t ibyte, new_blkid;
489 int epb = 1 << epbs;
490 int err, i, blkoff, tochk;
491 blkptr_t *bp;
492
493 ibyte = blkid << dn->dn_datablkshift;
494 err = dnode_next_offset(dn,
495 DNODE_FIND_HAVELOCK, &ibyte, 2, 1, 0);
496 new_blkid = ibyte >> dn->dn_datablkshift;
497 if (err == ESRCH) {
498 skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
499 break;
500 }
501 if (err) {
502 txh->txh_tx->tx_err = err;
503 break;
504 }
505 if (new_blkid > lastblk) {
506 skipped += (lastblk >> epbs) - (blkid >> epbs) + 1;
507 break;
508 }
509
510 if (new_blkid > blkid) {
511 ASSERT((new_blkid >> epbs) > (blkid >> epbs));
512 skipped += (new_blkid >> epbs) - (blkid >> epbs) - 1;
513 nblks -= new_blkid - blkid;
514 blkid = new_blkid;
515 }
516 blkoff = P2PHASE(blkid, epb);
517 tochk = MIN(epb - blkoff, nblks);
518
519 err = dbuf_hold_impl(dn, 1, blkid >> epbs, FALSE, FTAG, &dbuf);
520 if (err) {
521 txh->txh_tx->tx_err = err;
522 break;
523 }
524
525 txh->txh_memory_tohold += dbuf->db.db_size;
526
527 /*
528 * We don't check memory_tohold against DMU_MAX_ACCESS because
529 * memory_tohold is an over-estimation (especially the >L1
530 * indirect blocks), so it could fail. Callers should have
531 * already verified that they will not be holding too much
532 * memory.
533 */
534
535 err = dbuf_read(dbuf, NULL, DB_RF_HAVESTRUCT | DB_RF_CANFAIL);
536 if (err != 0) {
537 txh->txh_tx->tx_err = err;
538 dbuf_rele(dbuf, FTAG);
539 break;
540 }
541
542 bp = dbuf->db.db_data;
543 bp += blkoff;
544
545 for (i = 0; i < tochk; i++) {
546 if (dsl_dataset_block_freeable(ds, &bp[i],
547 bp[i].blk_birth)) {
548 dprintf_bp(&bp[i], "can free old%s", "");
549 space += bp_get_dsize(spa, &bp[i]);
550 }
551 unref += BP_GET_ASIZE(bp);
552 }
553 dbuf_rele(dbuf, FTAG);
554
555 ++nl1blks;
556 blkid += tochk;
557 nblks -= tochk;
558 }
559 rw_exit(&dn->dn_struct_rwlock);
560
561 /*
562 * Add in memory requirements of higher-level indirects.
563 * This assumes a worst-possible scenario for dn_nlevels and a
564 * worst-possible distribution of l1-blocks over the region to free.
565 */
566 {
567 uint64_t blkcnt = 1 + ((l0span >> epbs) >> epbs);
568 int level = 2;
569 /*
570 * Here we don't use DN_MAX_LEVEL, but calculate it with the
571 * given datablkshift and indblkshift. This makes the
572 * difference between 19 and 8 on large files.
573 */
574 int maxlevel = 2 + (DN_MAX_OFFSET_SHIFT - dn->dn_datablkshift) /
575 (dn->dn_indblkshift - SPA_BLKPTRSHIFT);
576
577 while (level++ < maxlevel) {
578 txh->txh_memory_tohold += MAX(MIN(blkcnt, nl1blks), 1)
579 << dn->dn_indblkshift;
580 blkcnt = 1 + (blkcnt >> epbs);
581 }
582 }
583
584 /* account for new level 1 indirect blocks that might show up */
585 if (skipped > 0) {
586 txh->txh_fudge += skipped << dn->dn_indblkshift;
587 skipped = MIN(skipped, DMU_MAX_DELETEBLKCNT >> epbs);
588 txh->txh_memory_tohold += skipped << dn->dn_indblkshift;
589 }
590 txh->txh_space_tofree += space;
591 txh->txh_space_tounref += unref;
592 }
593
594 /*
595 * This function marks the transaction as being a "net free". The end
596 * result is that refquotas will be disabled for this transaction, and
597 * this transaction will be able to use half of the pool space overhead
598 * (see dsl_pool_adjustedsize()). Therefore this function should only
599 * be called for transactions that we expect will not cause a net increase
600 * in the amount of space used (but it's OK if that is occasionally not true).
601 */
602 void
dmu_tx_mark_netfree(dmu_tx_t * tx)603 dmu_tx_mark_netfree(dmu_tx_t *tx)
604 {
605 dmu_tx_hold_t *txh;
606
607 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
608 DMU_NEW_OBJECT, THT_FREE, 0, 0);
609
610 /*
611 * Pretend that this operation will free 1GB of space. This
612 * should be large enough to cancel out the largest write.
613 * We don't want to use something like UINT64_MAX, because that would
614 * cause overflows when doing math with these values (e.g. in
615 * dmu_tx_try_assign()).
616 */
617 txh->txh_space_tofree = txh->txh_space_tounref = 1024 * 1024 * 1024;
618 }
619
620 void
dmu_tx_hold_free(dmu_tx_t * tx,uint64_t object,uint64_t off,uint64_t len)621 dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
622 {
623 dmu_tx_hold_t *txh;
624 dnode_t *dn;
625 int err;
626 zio_t *zio;
627
628 ASSERT(tx->tx_txg == 0);
629
630 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
631 object, THT_FREE, off, len);
632 if (txh == NULL)
633 return;
634 dn = txh->txh_dnode;
635 dmu_tx_count_dnode(txh);
636
637 if (off >= (dn->dn_maxblkid+1) * dn->dn_datablksz)
638 return;
639 if (len == DMU_OBJECT_END)
640 len = (dn->dn_maxblkid+1) * dn->dn_datablksz - off;
641
642 /*
643 * For i/o error checking, we read the first and last level-0
644 * blocks if they are not aligned, and all the level-1 blocks.
645 *
646 * Note: dbuf_free_range() assumes that we have not instantiated
647 * any level-0 dbufs that will be completely freed. Therefore we must
648 * exercise care to not read or count the first and last blocks
649 * if they are blocksize-aligned.
650 */
651 if (dn->dn_datablkshift == 0) {
652 if (off != 0 || len < dn->dn_datablksz)
653 dmu_tx_count_write(txh, 0, dn->dn_datablksz);
654 } else {
655 /* first block will be modified if it is not aligned */
656 if (!IS_P2ALIGNED(off, 1 << dn->dn_datablkshift))
657 dmu_tx_count_write(txh, off, 1);
658 /* last block will be modified if it is not aligned */
659 if (!IS_P2ALIGNED(off + len, 1 << dn->dn_datablkshift))
660 dmu_tx_count_write(txh, off+len, 1);
661 }
662
663 /*
664 * Check level-1 blocks.
665 */
666 if (dn->dn_nlevels > 1) {
667 int shift = dn->dn_datablkshift + dn->dn_indblkshift -
668 SPA_BLKPTRSHIFT;
669 uint64_t start = off >> shift;
670 uint64_t end = (off + len) >> shift;
671
672 ASSERT(dn->dn_indblkshift != 0);
673
674 /*
675 * dnode_reallocate() can result in an object with indirect
676 * blocks having an odd data block size. In this case,
677 * just check the single block.
678 */
679 if (dn->dn_datablkshift == 0)
680 start = end = 0;
681
682 zio = zio_root(tx->tx_pool->dp_spa,
683 NULL, NULL, ZIO_FLAG_CANFAIL);
684 for (uint64_t i = start; i <= end; i++) {
685 uint64_t ibyte = i << shift;
686 err = dnode_next_offset(dn, 0, &ibyte, 2, 1, 0);
687 i = ibyte >> shift;
688 if (err == ESRCH)
689 break;
690 if (err) {
691 tx->tx_err = err;
692 return;
693 }
694
695 err = dmu_tx_check_ioerr(zio, dn, 1, i);
696 if (err) {
697 tx->tx_err = err;
698 return;
699 }
700 }
701 err = zio_wait(zio);
702 if (err) {
703 tx->tx_err = err;
704 return;
705 }
706 }
707
708 dmu_tx_count_free(txh, off, len);
709 }
710
711 void
dmu_tx_hold_zap(dmu_tx_t * tx,uint64_t object,int add,const char * name)712 dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name)
713 {
714 dmu_tx_hold_t *txh;
715 dnode_t *dn;
716 dsl_dataset_phys_t *ds_phys;
717 uint64_t nblocks;
718 int epbs, err;
719
720 ASSERT(tx->tx_txg == 0);
721
722 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
723 object, THT_ZAP, add, (uintptr_t)name);
724 if (txh == NULL)
725 return;
726 dn = txh->txh_dnode;
727
728 dmu_tx_count_dnode(txh);
729
730 if (dn == NULL) {
731 /*
732 * We will be able to fit a new object's entries into one leaf
733 * block. So there will be at most 2 blocks total,
734 * including the header block.
735 */
736 dmu_tx_count_write(txh, 0, 2 << fzap_default_block_shift);
737 return;
738 }
739
740 ASSERT3P(DMU_OT_BYTESWAP(dn->dn_type), ==, DMU_BSWAP_ZAP);
741
742 if (dn->dn_maxblkid == 0 && !add) {
743 blkptr_t *bp;
744
745 /*
746 * If there is only one block (i.e. this is a micro-zap)
747 * and we are not adding anything, the accounting is simple.
748 */
749 err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
750 if (err) {
751 tx->tx_err = err;
752 return;
753 }
754
755 /*
756 * Use max block size here, since we don't know how much
757 * the size will change between now and the dbuf dirty call.
758 */
759 bp = &dn->dn_phys->dn_blkptr[0];
760 if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
761 bp, bp->blk_birth))
762 txh->txh_space_tooverwrite += MZAP_MAX_BLKSZ;
763 else
764 txh->txh_space_towrite += MZAP_MAX_BLKSZ;
765 if (!BP_IS_HOLE(bp))
766 txh->txh_space_tounref += MZAP_MAX_BLKSZ;
767 return;
768 }
769
770 if (dn->dn_maxblkid > 0 && name) {
771 /*
772 * access the name in this fat-zap so that we'll check
773 * for i/o errors to the leaf blocks, etc.
774 */
775 err = zap_lookup(dn->dn_objset, dn->dn_object, name,
776 8, 0, NULL);
777 if (err == EIO) {
778 tx->tx_err = err;
779 return;
780 }
781 }
782
783 err = zap_count_write(dn->dn_objset, dn->dn_object, name, add,
784 &txh->txh_space_towrite, &txh->txh_space_tooverwrite);
785
786 /*
787 * If the modified blocks are scattered to the four winds,
788 * we'll have to modify an indirect twig for each.
789 */
790 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
791 ds_phys = dsl_dataset_phys(dn->dn_objset->os_dsl_dataset);
792 for (nblocks = dn->dn_maxblkid >> epbs; nblocks != 0; nblocks >>= epbs)
793 if (ds_phys->ds_prev_snap_obj)
794 txh->txh_space_towrite += 3 << dn->dn_indblkshift;
795 else
796 txh->txh_space_tooverwrite += 3 << dn->dn_indblkshift;
797 }
798
799 void
dmu_tx_hold_bonus(dmu_tx_t * tx,uint64_t object)800 dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object)
801 {
802 dmu_tx_hold_t *txh;
803
804 ASSERT(tx->tx_txg == 0);
805
806 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
807 object, THT_BONUS, 0, 0);
808 if (txh)
809 dmu_tx_count_dnode(txh);
810 }
811
812 void
dmu_tx_hold_space(dmu_tx_t * tx,uint64_t space)813 dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space)
814 {
815 dmu_tx_hold_t *txh;
816 ASSERT(tx->tx_txg == 0);
817
818 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
819 DMU_NEW_OBJECT, THT_SPACE, space, 0);
820
821 txh->txh_space_towrite += space;
822 }
823
824 int
dmu_tx_holds(dmu_tx_t * tx,uint64_t object)825 dmu_tx_holds(dmu_tx_t *tx, uint64_t object)
826 {
827 dmu_tx_hold_t *txh;
828 int holds = 0;
829
830 /*
831 * By asserting that the tx is assigned, we're counting the
832 * number of dn_tx_holds, which is the same as the number of
833 * dn_holds. Otherwise, we'd be counting dn_holds, but
834 * dn_tx_holds could be 0.
835 */
836 ASSERT(tx->tx_txg != 0);
837
838 /* if (tx->tx_anyobj == TRUE) */
839 /* return (0); */
840
841 for (txh = list_head(&tx->tx_holds); txh;
842 txh = list_next(&tx->tx_holds, txh)) {
843 if (txh->txh_dnode && txh->txh_dnode->dn_object == object)
844 holds++;
845 }
846
847 return (holds);
848 }
849
850 #ifdef ZFS_DEBUG
851 void
dmu_tx_dirty_buf(dmu_tx_t * tx,dmu_buf_impl_t * db)852 dmu_tx_dirty_buf(dmu_tx_t *tx, dmu_buf_impl_t *db)
853 {
854 dmu_tx_hold_t *txh;
855 int match_object = FALSE, match_offset = FALSE;
856 dnode_t *dn;
857
858 DB_DNODE_ENTER(db);
859 dn = DB_DNODE(db);
860 ASSERT(tx->tx_txg != 0);
861 ASSERT(tx->tx_objset == NULL || dn->dn_objset == tx->tx_objset);
862 ASSERT3U(dn->dn_object, ==, db->db.db_object);
863
864 if (tx->tx_anyobj) {
865 DB_DNODE_EXIT(db);
866 return;
867 }
868
869 /* XXX No checking on the meta dnode for now */
870 if (db->db.db_object == DMU_META_DNODE_OBJECT) {
871 DB_DNODE_EXIT(db);
872 return;
873 }
874
875 for (txh = list_head(&tx->tx_holds); txh;
876 txh = list_next(&tx->tx_holds, txh)) {
877 ASSERT(dn == NULL || dn->dn_assigned_txg == tx->tx_txg);
878 if (txh->txh_dnode == dn && txh->txh_type != THT_NEWOBJECT)
879 match_object = TRUE;
880 if (txh->txh_dnode == NULL || txh->txh_dnode == dn) {
881 int datablkshift = dn->dn_datablkshift ?
882 dn->dn_datablkshift : SPA_MAXBLOCKSHIFT;
883 int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
884 int shift = datablkshift + epbs * db->db_level;
885 uint64_t beginblk = shift >= 64 ? 0 :
886 (txh->txh_arg1 >> shift);
887 uint64_t endblk = shift >= 64 ? 0 :
888 ((txh->txh_arg1 + txh->txh_arg2 - 1) >> shift);
889 uint64_t blkid = db->db_blkid;
890
891 /* XXX txh_arg2 better not be zero... */
892
893 dprintf("found txh type %x beginblk=%llx endblk=%llx\n",
894 txh->txh_type, beginblk, endblk);
895
896 switch (txh->txh_type) {
897 case THT_WRITE:
898 if (blkid >= beginblk && blkid <= endblk)
899 match_offset = TRUE;
900 /*
901 * We will let this hold work for the bonus
902 * or spill buffer so that we don't need to
903 * hold it when creating a new object.
904 */
905 if (blkid == DMU_BONUS_BLKID ||
906 blkid == DMU_SPILL_BLKID)
907 match_offset = TRUE;
908 /*
909 * They might have to increase nlevels,
910 * thus dirtying the new TLIBs. Or the
911 * might have to change the block size,
912 * thus dirying the new lvl=0 blk=0.
913 */
914 if (blkid == 0)
915 match_offset = TRUE;
916 break;
917 case THT_FREE:
918 /*
919 * We will dirty all the level 1 blocks in
920 * the free range and perhaps the first and
921 * last level 0 block.
922 */
923 if (blkid >= beginblk && (blkid <= endblk ||
924 txh->txh_arg2 == DMU_OBJECT_END))
925 match_offset = TRUE;
926 break;
927 case THT_SPILL:
928 if (blkid == DMU_SPILL_BLKID)
929 match_offset = TRUE;
930 break;
931 case THT_BONUS:
932 if (blkid == DMU_BONUS_BLKID)
933 match_offset = TRUE;
934 break;
935 case THT_ZAP:
936 match_offset = TRUE;
937 break;
938 case THT_NEWOBJECT:
939 match_object = TRUE;
940 break;
941 default:
942 ASSERT(!"bad txh_type");
943 }
944 }
945 if (match_object && match_offset) {
946 DB_DNODE_EXIT(db);
947 return;
948 }
949 }
950 DB_DNODE_EXIT(db);
951 panic("dirtying dbuf obj=%llx lvl=%u blkid=%llx but not tx_held\n",
952 (u_longlong_t)db->db.db_object, db->db_level,
953 (u_longlong_t)db->db_blkid);
954 }
955 #endif
956
957 /*
958 * If we can't do 10 iops, something is wrong. Let us go ahead
959 * and hit zfs_dirty_data_max.
960 */
961 hrtime_t zfs_delay_max_ns = MSEC2NSEC(100);
962 int zfs_delay_resolution_ns = 100 * 1000; /* 100 microseconds */
963
964 /*
965 * We delay transactions when we've determined that the backend storage
966 * isn't able to accommodate the rate of incoming writes.
967 *
968 * If there is already a transaction waiting, we delay relative to when
969 * that transaction finishes waiting. This way the calculated min_time
970 * is independent of the number of threads concurrently executing
971 * transactions.
972 *
973 * If we are the only waiter, wait relative to when the transaction
974 * started, rather than the current time. This credits the transaction for
975 * "time already served", e.g. reading indirect blocks.
976 *
977 * The minimum time for a transaction to take is calculated as:
978 * min_time = scale * (dirty - min) / (max - dirty)
979 * min_time is then capped at zfs_delay_max_ns.
980 *
981 * The delay has two degrees of freedom that can be adjusted via tunables.
982 * The percentage of dirty data at which we start to delay is defined by
983 * zfs_delay_min_dirty_percent. This should typically be at or above
984 * zfs_vdev_async_write_active_max_dirty_percent so that we only start to
985 * delay after writing at full speed has failed to keep up with the incoming
986 * write rate. The scale of the curve is defined by zfs_delay_scale. Roughly
987 * speaking, this variable determines the amount of delay at the midpoint of
988 * the curve.
989 *
990 * delay
991 * 10ms +-------------------------------------------------------------*+
992 * | *|
993 * 9ms + *+
994 * | *|
995 * 8ms + *+
996 * | * |
997 * 7ms + * +
998 * | * |
999 * 6ms + * +
1000 * | * |
1001 * 5ms + * +
1002 * | * |
1003 * 4ms + * +
1004 * | * |
1005 * 3ms + * +
1006 * | * |
1007 * 2ms + (midpoint) * +
1008 * | | ** |
1009 * 1ms + v *** +
1010 * | zfs_delay_scale ----------> ******** |
1011 * 0 +-------------------------------------*********----------------+
1012 * 0% <- zfs_dirty_data_max -> 100%
1013 *
1014 * Note that since the delay is added to the outstanding time remaining on the
1015 * most recent transaction, the delay is effectively the inverse of IOPS.
1016 * Here the midpoint of 500us translates to 2000 IOPS. The shape of the curve
1017 * was chosen such that small changes in the amount of accumulated dirty data
1018 * in the first 3/4 of the curve yield relatively small differences in the
1019 * amount of delay.
1020 *
1021 * The effects can be easier to understand when the amount of delay is
1022 * represented on a log scale:
1023 *
1024 * delay
1025 * 100ms +-------------------------------------------------------------++
1026 * + +
1027 * | |
1028 * + *+
1029 * 10ms + *+
1030 * + ** +
1031 * | (midpoint) ** |
1032 * + | ** +
1033 * 1ms + v **** +
1034 * + zfs_delay_scale ----------> ***** +
1035 * | **** |
1036 * + **** +
1037 * 100us + ** +
1038 * + * +
1039 * | * |
1040 * + * +
1041 * 10us + * +
1042 * + +
1043 * | |
1044 * + +
1045 * +--------------------------------------------------------------+
1046 * 0% <- zfs_dirty_data_max -> 100%
1047 *
1048 * Note here that only as the amount of dirty data approaches its limit does
1049 * the delay start to increase rapidly. The goal of a properly tuned system
1050 * should be to keep the amount of dirty data out of that range by first
1051 * ensuring that the appropriate limits are set for the I/O scheduler to reach
1052 * optimal throughput on the backend storage, and then by changing the value
1053 * of zfs_delay_scale to increase the steepness of the curve.
1054 */
1055 static void
dmu_tx_delay(dmu_tx_t * tx,uint64_t dirty)1056 dmu_tx_delay(dmu_tx_t *tx, uint64_t dirty)
1057 {
1058 dsl_pool_t *dp = tx->tx_pool;
1059 uint64_t delay_min_bytes =
1060 zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100;
1061 hrtime_t wakeup, min_tx_time, now;
1062
1063 if (dirty <= delay_min_bytes)
1064 return;
1065
1066 /*
1067 * The caller has already waited until we are under the max.
1068 * We make them pass us the amount of dirty data so we don't
1069 * have to handle the case of it being >= the max, which could
1070 * cause a divide-by-zero if it's == the max.
1071 */
1072 ASSERT3U(dirty, <, zfs_dirty_data_max);
1073
1074 now = gethrtime();
1075 min_tx_time = zfs_delay_scale *
1076 (dirty - delay_min_bytes) / (zfs_dirty_data_max - dirty);
1077 if (now > tx->tx_start + min_tx_time)
1078 return;
1079
1080 min_tx_time = MIN(min_tx_time, zfs_delay_max_ns);
1081
1082 DTRACE_PROBE3(delay__mintime, dmu_tx_t *, tx, uint64_t, dirty,
1083 uint64_t, min_tx_time);
1084
1085 mutex_enter(&dp->dp_lock);
1086 wakeup = MAX(tx->tx_start + min_tx_time,
1087 dp->dp_last_wakeup + min_tx_time);
1088 dp->dp_last_wakeup = wakeup;
1089 mutex_exit(&dp->dp_lock);
1090
1091 #ifdef _KERNEL
1092 #ifdef illumos
1093 mutex_enter(&curthread->t_delay_lock);
1094 while (cv_timedwait_hires(&curthread->t_delay_cv,
1095 &curthread->t_delay_lock, wakeup, zfs_delay_resolution_ns,
1096 CALLOUT_FLAG_ABSOLUTE | CALLOUT_FLAG_ROUNDUP) > 0)
1097 continue;
1098 mutex_exit(&curthread->t_delay_lock);
1099 #else
1100 pause_sbt("dmu_tx_delay", wakeup * SBT_1NS,
1101 zfs_delay_resolution_ns * SBT_1NS, C_ABSOLUTE);
1102 #endif
1103 #else
1104 hrtime_t delta = wakeup - gethrtime();
1105 struct timespec ts;
1106 ts.tv_sec = delta / NANOSEC;
1107 ts.tv_nsec = delta % NANOSEC;
1108 (void) nanosleep(&ts, NULL);
1109 #endif
1110 }
1111
1112 static int
dmu_tx_try_assign(dmu_tx_t * tx,txg_how_t txg_how)1113 dmu_tx_try_assign(dmu_tx_t *tx, txg_how_t txg_how)
1114 {
1115 dmu_tx_hold_t *txh;
1116 spa_t *spa = tx->tx_pool->dp_spa;
1117 uint64_t memory, asize, fsize, usize;
1118 uint64_t towrite, tofree, tooverwrite, tounref, tohold, fudge;
1119
1120 ASSERT0(tx->tx_txg);
1121
1122 if (tx->tx_err)
1123 return (tx->tx_err);
1124
1125 if (spa_suspended(spa)) {
1126 /*
1127 * If the user has indicated a blocking failure mode
1128 * then return ERESTART which will block in dmu_tx_wait().
1129 * Otherwise, return EIO so that an error can get
1130 * propagated back to the VOP calls.
1131 *
1132 * Note that we always honor the txg_how flag regardless
1133 * of the failuremode setting.
1134 */
1135 if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_CONTINUE &&
1136 txg_how != TXG_WAIT)
1137 return (SET_ERROR(EIO));
1138
1139 return (SET_ERROR(ERESTART));
1140 }
1141
1142 if (!tx->tx_waited &&
1143 dsl_pool_need_dirty_delay(tx->tx_pool)) {
1144 tx->tx_wait_dirty = B_TRUE;
1145 return (SET_ERROR(ERESTART));
1146 }
1147
1148 tx->tx_txg = txg_hold_open(tx->tx_pool, &tx->tx_txgh);
1149 tx->tx_needassign_txh = NULL;
1150
1151 /*
1152 * NB: No error returns are allowed after txg_hold_open, but
1153 * before processing the dnode holds, due to the
1154 * dmu_tx_unassign() logic.
1155 */
1156
1157 towrite = tofree = tooverwrite = tounref = tohold = fudge = 0;
1158 for (txh = list_head(&tx->tx_holds); txh;
1159 txh = list_next(&tx->tx_holds, txh)) {
1160 dnode_t *dn = txh->txh_dnode;
1161 if (dn != NULL) {
1162 mutex_enter(&dn->dn_mtx);
1163 if (dn->dn_assigned_txg == tx->tx_txg - 1) {
1164 mutex_exit(&dn->dn_mtx);
1165 tx->tx_needassign_txh = txh;
1166 return (SET_ERROR(ERESTART));
1167 }
1168 if (dn->dn_assigned_txg == 0)
1169 dn->dn_assigned_txg = tx->tx_txg;
1170 ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
1171 (void) refcount_add(&dn->dn_tx_holds, tx);
1172 mutex_exit(&dn->dn_mtx);
1173 }
1174 towrite += txh->txh_space_towrite;
1175 tofree += txh->txh_space_tofree;
1176 tooverwrite += txh->txh_space_tooverwrite;
1177 tounref += txh->txh_space_tounref;
1178 tohold += txh->txh_memory_tohold;
1179 fudge += txh->txh_fudge;
1180 }
1181
1182 /*
1183 * If a snapshot has been taken since we made our estimates,
1184 * assume that we won't be able to free or overwrite anything.
1185 */
1186 if (tx->tx_objset &&
1187 dsl_dataset_prev_snap_txg(tx->tx_objset->os_dsl_dataset) >
1188 tx->tx_lastsnap_txg) {
1189 towrite += tooverwrite;
1190 tooverwrite = tofree = 0;
1191 }
1192
1193 /* needed allocation: worst-case estimate of write space */
1194 asize = spa_get_asize(tx->tx_pool->dp_spa, towrite + tooverwrite);
1195 /* freed space estimate: worst-case overwrite + free estimate */
1196 fsize = spa_get_asize(tx->tx_pool->dp_spa, tooverwrite) + tofree;
1197 /* convert unrefd space to worst-case estimate */
1198 usize = spa_get_asize(tx->tx_pool->dp_spa, tounref);
1199 /* calculate memory footprint estimate */
1200 memory = towrite + tooverwrite + tohold;
1201
1202 #ifdef ZFS_DEBUG
1203 /*
1204 * Add in 'tohold' to account for our dirty holds on this memory
1205 * XXX - the "fudge" factor is to account for skipped blocks that
1206 * we missed because dnode_next_offset() misses in-core-only blocks.
1207 */
1208 tx->tx_space_towrite = asize +
1209 spa_get_asize(tx->tx_pool->dp_spa, tohold + fudge);
1210 tx->tx_space_tofree = tofree;
1211 tx->tx_space_tooverwrite = tooverwrite;
1212 tx->tx_space_tounref = tounref;
1213 #endif
1214
1215 if (tx->tx_dir && asize != 0) {
1216 int err = dsl_dir_tempreserve_space(tx->tx_dir, memory,
1217 asize, fsize, usize, &tx->tx_tempreserve_cookie, tx);
1218 if (err)
1219 return (err);
1220 }
1221
1222 return (0);
1223 }
1224
1225 static void
dmu_tx_unassign(dmu_tx_t * tx)1226 dmu_tx_unassign(dmu_tx_t *tx)
1227 {
1228 dmu_tx_hold_t *txh;
1229
1230 if (tx->tx_txg == 0)
1231 return;
1232
1233 txg_rele_to_quiesce(&tx->tx_txgh);
1234
1235 /*
1236 * Walk the transaction's hold list, removing the hold on the
1237 * associated dnode, and notifying waiters if the refcount drops to 0.
1238 */
1239 for (txh = list_head(&tx->tx_holds); txh != tx->tx_needassign_txh;
1240 txh = list_next(&tx->tx_holds, txh)) {
1241 dnode_t *dn = txh->txh_dnode;
1242
1243 if (dn == NULL)
1244 continue;
1245 mutex_enter(&dn->dn_mtx);
1246 ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
1247
1248 if (refcount_remove(&dn->dn_tx_holds, tx) == 0) {
1249 dn->dn_assigned_txg = 0;
1250 cv_broadcast(&dn->dn_notxholds);
1251 }
1252 mutex_exit(&dn->dn_mtx);
1253 }
1254
1255 txg_rele_to_sync(&tx->tx_txgh);
1256
1257 tx->tx_lasttried_txg = tx->tx_txg;
1258 tx->tx_txg = 0;
1259 }
1260
1261 /*
1262 * Assign tx to a transaction group. txg_how can be one of:
1263 *
1264 * (1) TXG_WAIT. If the current open txg is full, waits until there's
1265 * a new one. This should be used when you're not holding locks.
1266 * It will only fail if we're truly out of space (or over quota).
1267 *
1268 * (2) TXG_NOWAIT. If we can't assign into the current open txg without
1269 * blocking, returns immediately with ERESTART. This should be used
1270 * whenever you're holding locks. On an ERESTART error, the caller
1271 * should drop locks, do a dmu_tx_wait(tx), and try again.
1272 *
1273 * (3) TXG_WAITED. Like TXG_NOWAIT, but indicates that dmu_tx_wait()
1274 * has already been called on behalf of this operation (though
1275 * most likely on a different tx).
1276 */
1277 int
dmu_tx_assign(dmu_tx_t * tx,txg_how_t txg_how)1278 dmu_tx_assign(dmu_tx_t *tx, txg_how_t txg_how)
1279 {
1280 int err;
1281
1282 ASSERT(tx->tx_txg == 0);
1283 ASSERT(txg_how == TXG_WAIT || txg_how == TXG_NOWAIT ||
1284 txg_how == TXG_WAITED);
1285 ASSERT(!dsl_pool_sync_context(tx->tx_pool));
1286
1287 /* If we might wait, we must not hold the config lock. */
1288 ASSERT(txg_how != TXG_WAIT || !dsl_pool_config_held(tx->tx_pool));
1289
1290 if (txg_how == TXG_WAITED)
1291 tx->tx_waited = B_TRUE;
1292
1293 while ((err = dmu_tx_try_assign(tx, txg_how)) != 0) {
1294 dmu_tx_unassign(tx);
1295
1296 if (err != ERESTART || txg_how != TXG_WAIT)
1297 return (err);
1298
1299 dmu_tx_wait(tx);
1300 }
1301
1302 txg_rele_to_quiesce(&tx->tx_txgh);
1303
1304 return (0);
1305 }
1306
1307 void
dmu_tx_wait(dmu_tx_t * tx)1308 dmu_tx_wait(dmu_tx_t *tx)
1309 {
1310 spa_t *spa = tx->tx_pool->dp_spa;
1311 dsl_pool_t *dp = tx->tx_pool;
1312
1313 ASSERT(tx->tx_txg == 0);
1314 ASSERT(!dsl_pool_config_held(tx->tx_pool));
1315
1316 if (tx->tx_wait_dirty) {
1317 /*
1318 * dmu_tx_try_assign() has determined that we need to wait
1319 * because we've consumed much or all of the dirty buffer
1320 * space.
1321 */
1322 mutex_enter(&dp->dp_lock);
1323 while (dp->dp_dirty_total >= zfs_dirty_data_max)
1324 cv_wait(&dp->dp_spaceavail_cv, &dp->dp_lock);
1325 uint64_t dirty = dp->dp_dirty_total;
1326 mutex_exit(&dp->dp_lock);
1327
1328 dmu_tx_delay(tx, dirty);
1329
1330 tx->tx_wait_dirty = B_FALSE;
1331
1332 /*
1333 * Note: setting tx_waited only has effect if the caller
1334 * used TX_WAIT. Otherwise they are going to destroy
1335 * this tx and try again. The common case, zfs_write(),
1336 * uses TX_WAIT.
1337 */
1338 tx->tx_waited = B_TRUE;
1339 } else if (spa_suspended(spa) || tx->tx_lasttried_txg == 0) {
1340 /*
1341 * If the pool is suspended we need to wait until it
1342 * is resumed. Note that it's possible that the pool
1343 * has become active after this thread has tried to
1344 * obtain a tx. If that's the case then tx_lasttried_txg
1345 * would not have been set.
1346 */
1347 txg_wait_synced(dp, spa_last_synced_txg(spa) + 1);
1348 } else if (tx->tx_needassign_txh) {
1349 /*
1350 * A dnode is assigned to the quiescing txg. Wait for its
1351 * transaction to complete.
1352 */
1353 dnode_t *dn = tx->tx_needassign_txh->txh_dnode;
1354
1355 mutex_enter(&dn->dn_mtx);
1356 while (dn->dn_assigned_txg == tx->tx_lasttried_txg - 1)
1357 cv_wait(&dn->dn_notxholds, &dn->dn_mtx);
1358 mutex_exit(&dn->dn_mtx);
1359 tx->tx_needassign_txh = NULL;
1360 } else {
1361 txg_wait_open(tx->tx_pool, tx->tx_lasttried_txg + 1);
1362 }
1363 }
1364
1365 void
dmu_tx_willuse_space(dmu_tx_t * tx,int64_t delta)1366 dmu_tx_willuse_space(dmu_tx_t *tx, int64_t delta)
1367 {
1368 #ifdef ZFS_DEBUG
1369 if (tx->tx_dir == NULL || delta == 0)
1370 return;
1371
1372 if (delta > 0) {
1373 ASSERT3U(refcount_count(&tx->tx_space_written) + delta, <=,
1374 tx->tx_space_towrite);
1375 (void) refcount_add_many(&tx->tx_space_written, delta, NULL);
1376 } else {
1377 (void) refcount_add_many(&tx->tx_space_freed, -delta, NULL);
1378 }
1379 #endif
1380 }
1381
1382 void
dmu_tx_commit(dmu_tx_t * tx)1383 dmu_tx_commit(dmu_tx_t *tx)
1384 {
1385 dmu_tx_hold_t *txh;
1386
1387 ASSERT(tx->tx_txg != 0);
1388
1389 /*
1390 * Go through the transaction's hold list and remove holds on
1391 * associated dnodes, notifying waiters if no holds remain.
1392 */
1393 while (txh = list_head(&tx->tx_holds)) {
1394 dnode_t *dn = txh->txh_dnode;
1395
1396 list_remove(&tx->tx_holds, txh);
1397 kmem_free(txh, sizeof (dmu_tx_hold_t));
1398 if (dn == NULL)
1399 continue;
1400 mutex_enter(&dn->dn_mtx);
1401 ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg);
1402
1403 if (refcount_remove(&dn->dn_tx_holds, tx) == 0) {
1404 dn->dn_assigned_txg = 0;
1405 cv_broadcast(&dn->dn_notxholds);
1406 }
1407 mutex_exit(&dn->dn_mtx);
1408 dnode_rele(dn, tx);
1409 }
1410
1411 if (tx->tx_tempreserve_cookie)
1412 dsl_dir_tempreserve_clear(tx->tx_tempreserve_cookie, tx);
1413
1414 if (!list_is_empty(&tx->tx_callbacks))
1415 txg_register_callbacks(&tx->tx_txgh, &tx->tx_callbacks);
1416
1417 if (tx->tx_anyobj == FALSE)
1418 txg_rele_to_sync(&tx->tx_txgh);
1419
1420 list_destroy(&tx->tx_callbacks);
1421 list_destroy(&tx->tx_holds);
1422 #ifdef ZFS_DEBUG
1423 dprintf("towrite=%llu written=%llu tofree=%llu freed=%llu\n",
1424 tx->tx_space_towrite, refcount_count(&tx->tx_space_written),
1425 tx->tx_space_tofree, refcount_count(&tx->tx_space_freed));
1426 refcount_destroy_many(&tx->tx_space_written,
1427 refcount_count(&tx->tx_space_written));
1428 refcount_destroy_many(&tx->tx_space_freed,
1429 refcount_count(&tx->tx_space_freed));
1430 #endif
1431 kmem_free(tx, sizeof (dmu_tx_t));
1432 }
1433
1434 void
dmu_tx_abort(dmu_tx_t * tx)1435 dmu_tx_abort(dmu_tx_t *tx)
1436 {
1437 dmu_tx_hold_t *txh;
1438
1439 ASSERT(tx->tx_txg == 0);
1440
1441 while (txh = list_head(&tx->tx_holds)) {
1442 dnode_t *dn = txh->txh_dnode;
1443
1444 list_remove(&tx->tx_holds, txh);
1445 kmem_free(txh, sizeof (dmu_tx_hold_t));
1446 if (dn != NULL)
1447 dnode_rele(dn, tx);
1448 }
1449
1450 /*
1451 * Call any registered callbacks with an error code.
1452 */
1453 if (!list_is_empty(&tx->tx_callbacks))
1454 dmu_tx_do_callbacks(&tx->tx_callbacks, ECANCELED);
1455
1456 list_destroy(&tx->tx_callbacks);
1457 list_destroy(&tx->tx_holds);
1458 #ifdef ZFS_DEBUG
1459 refcount_destroy_many(&tx->tx_space_written,
1460 refcount_count(&tx->tx_space_written));
1461 refcount_destroy_many(&tx->tx_space_freed,
1462 refcount_count(&tx->tx_space_freed));
1463 #endif
1464 kmem_free(tx, sizeof (dmu_tx_t));
1465 }
1466
1467 uint64_t
dmu_tx_get_txg(dmu_tx_t * tx)1468 dmu_tx_get_txg(dmu_tx_t *tx)
1469 {
1470 ASSERT(tx->tx_txg != 0);
1471 return (tx->tx_txg);
1472 }
1473
1474 dsl_pool_t *
dmu_tx_pool(dmu_tx_t * tx)1475 dmu_tx_pool(dmu_tx_t *tx)
1476 {
1477 ASSERT(tx->tx_pool != NULL);
1478 return (tx->tx_pool);
1479 }
1480
1481
1482 void
dmu_tx_callback_register(dmu_tx_t * tx,dmu_tx_callback_func_t * func,void * data)1483 dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *func, void *data)
1484 {
1485 dmu_tx_callback_t *dcb;
1486
1487 dcb = kmem_alloc(sizeof (dmu_tx_callback_t), KM_SLEEP);
1488
1489 dcb->dcb_func = func;
1490 dcb->dcb_data = data;
1491
1492 list_insert_tail(&tx->tx_callbacks, dcb);
1493 }
1494
1495 /*
1496 * Call all the commit callbacks on a list, with a given error code.
1497 */
1498 void
dmu_tx_do_callbacks(list_t * cb_list,int error)1499 dmu_tx_do_callbacks(list_t *cb_list, int error)
1500 {
1501 dmu_tx_callback_t *dcb;
1502
1503 while (dcb = list_head(cb_list)) {
1504 list_remove(cb_list, dcb);
1505 dcb->dcb_func(dcb->dcb_data, error);
1506 kmem_free(dcb, sizeof (dmu_tx_callback_t));
1507 }
1508 }
1509
1510 /*
1511 * Interface to hold a bunch of attributes.
1512 * used for creating new files.
1513 * attrsize is the total size of all attributes
1514 * to be added during object creation
1515 *
1516 * For updating/adding a single attribute dmu_tx_hold_sa() should be used.
1517 */
1518
1519 /*
1520 * hold necessary attribute name for attribute registration.
1521 * should be a very rare case where this is needed. If it does
1522 * happen it would only happen on the first write to the file system.
1523 */
1524 static void
dmu_tx_sa_registration_hold(sa_os_t * sa,dmu_tx_t * tx)1525 dmu_tx_sa_registration_hold(sa_os_t *sa, dmu_tx_t *tx)
1526 {
1527 int i;
1528
1529 if (!sa->sa_need_attr_registration)
1530 return;
1531
1532 for (i = 0; i != sa->sa_num_attrs; i++) {
1533 if (!sa->sa_attr_table[i].sa_registered) {
1534 if (sa->sa_reg_attr_obj)
1535 dmu_tx_hold_zap(tx, sa->sa_reg_attr_obj,
1536 B_TRUE, sa->sa_attr_table[i].sa_name);
1537 else
1538 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT,
1539 B_TRUE, sa->sa_attr_table[i].sa_name);
1540 }
1541 }
1542 }
1543
1544
1545 void
dmu_tx_hold_spill(dmu_tx_t * tx,uint64_t object)1546 dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object)
1547 {
1548 dnode_t *dn;
1549 dmu_tx_hold_t *txh;
1550
1551 txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, object,
1552 THT_SPILL, 0, 0);
1553
1554 dn = txh->txh_dnode;
1555
1556 if (dn == NULL)
1557 return;
1558
1559 /* If blkptr doesn't exist then add space to towrite */
1560 if (!(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) {
1561 txh->txh_space_towrite += SPA_OLD_MAXBLOCKSIZE;
1562 } else {
1563 blkptr_t *bp;
1564
1565 bp = &dn->dn_phys->dn_spill;
1566 if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
1567 bp, bp->blk_birth))
1568 txh->txh_space_tooverwrite += SPA_OLD_MAXBLOCKSIZE;
1569 else
1570 txh->txh_space_towrite += SPA_OLD_MAXBLOCKSIZE;
1571 if (!BP_IS_HOLE(bp))
1572 txh->txh_space_tounref += SPA_OLD_MAXBLOCKSIZE;
1573 }
1574 }
1575
1576 void
dmu_tx_hold_sa_create(dmu_tx_t * tx,int attrsize)1577 dmu_tx_hold_sa_create(dmu_tx_t *tx, int attrsize)
1578 {
1579 sa_os_t *sa = tx->tx_objset->os_sa;
1580
1581 dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
1582
1583 if (tx->tx_objset->os_sa->sa_master_obj == 0)
1584 return;
1585
1586 if (tx->tx_objset->os_sa->sa_layout_attr_obj)
1587 dmu_tx_hold_zap(tx, sa->sa_layout_attr_obj, B_TRUE, NULL);
1588 else {
1589 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_LAYOUTS);
1590 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_REGISTRY);
1591 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1592 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1593 }
1594
1595 dmu_tx_sa_registration_hold(sa, tx);
1596
1597 if (attrsize <= DN_MAX_BONUSLEN && !sa->sa_force_spill)
1598 return;
1599
1600 (void) dmu_tx_hold_object_impl(tx, tx->tx_objset, DMU_NEW_OBJECT,
1601 THT_SPILL, 0, 0);
1602 }
1603
1604 /*
1605 * Hold SA attribute
1606 *
1607 * dmu_tx_hold_sa(dmu_tx_t *tx, sa_handle_t *, attribute, add, size)
1608 *
1609 * variable_size is the total size of all variable sized attributes
1610 * passed to this function. It is not the total size of all
1611 * variable size attributes that *may* exist on this object.
1612 */
1613 void
dmu_tx_hold_sa(dmu_tx_t * tx,sa_handle_t * hdl,boolean_t may_grow)1614 dmu_tx_hold_sa(dmu_tx_t *tx, sa_handle_t *hdl, boolean_t may_grow)
1615 {
1616 uint64_t object;
1617 sa_os_t *sa = tx->tx_objset->os_sa;
1618
1619 ASSERT(hdl != NULL);
1620
1621 object = sa_handle_object(hdl);
1622
1623 dmu_tx_hold_bonus(tx, object);
1624
1625 if (tx->tx_objset->os_sa->sa_master_obj == 0)
1626 return;
1627
1628 if (tx->tx_objset->os_sa->sa_reg_attr_obj == 0 ||
1629 tx->tx_objset->os_sa->sa_layout_attr_obj == 0) {
1630 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_LAYOUTS);
1631 dmu_tx_hold_zap(tx, sa->sa_master_obj, B_TRUE, SA_REGISTRY);
1632 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1633 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, B_TRUE, NULL);
1634 }
1635
1636 dmu_tx_sa_registration_hold(sa, tx);
1637
1638 if (may_grow && tx->tx_objset->os_sa->sa_layout_attr_obj)
1639 dmu_tx_hold_zap(tx, sa->sa_layout_attr_obj, B_TRUE, NULL);
1640
1641 if (sa->sa_force_spill || may_grow || hdl->sa_spill) {
1642 ASSERT(tx->tx_txg == 0);
1643 dmu_tx_hold_spill(tx, object);
1644 } else {
1645 dmu_buf_impl_t *db = (dmu_buf_impl_t *)hdl->sa_bonus;
1646 dnode_t *dn;
1647
1648 DB_DNODE_ENTER(db);
1649 dn = DB_DNODE(db);
1650 if (dn->dn_have_spill) {
1651 ASSERT(tx->tx_txg == 0);
1652 dmu_tx_hold_spill(tx, object);
1653 }
1654 DB_DNODE_EXIT(db);
1655 }
1656 }
1657