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