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) 2008-2010 Lawrence Livermore National Security, LLC. 23 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). 24 * Rewritten for Linux by Brian Behlendorf <behlendorf1@llnl.gov>. 25 * LLNL-CODE-403049. 26 * 27 * ZFS volume emulation driver. 28 * 29 * Makes a DMU object look like a volume of arbitrary size, up to 2^64 bytes. 30 * Volumes are accessed through the symbolic links named: 31 * 32 * /dev/<pool_name>/<dataset_name> 33 * 34 * Volumes are persistent through reboot and module load. No user command 35 * needs to be run before opening and using a device. 36 * 37 * Copyright 2014 Nexenta Systems, Inc. All rights reserved. 38 * Copyright (c) 2016 Actifio, Inc. All rights reserved. 39 * Copyright (c) 2012, 2019 by Delphix. All rights reserved. 40 */ 41 42 /* 43 * Note on locking of zvol state structures. 44 * 45 * These structures are used to maintain internal state used to emulate block 46 * devices on top of zvols. In particular, management of device minor number 47 * operations - create, remove, rename, and set_snapdev - involves access to 48 * these structures. The zvol_state_lock is primarily used to protect the 49 * zvol_state_list. The zv->zv_state_lock is used to protect the contents 50 * of the zvol_state_t structures, as well as to make sure that when the 51 * time comes to remove the structure from the list, it is not in use, and 52 * therefore, it can be taken off zvol_state_list and freed. 53 * 54 * The zv_suspend_lock was introduced to allow for suspending I/O to a zvol, 55 * e.g. for the duration of receive and rollback operations. This lock can be 56 * held for significant periods of time. Given that it is undesirable to hold 57 * mutexes for long periods of time, the following lock ordering applies: 58 * - take zvol_state_lock if necessary, to protect zvol_state_list 59 * - take zv_suspend_lock if necessary, by the code path in question 60 * - take zv_state_lock to protect zvol_state_t 61 * 62 * The minor operations are issued to spa->spa_zvol_taskq queues, that are 63 * single-threaded (to preserve order of minor operations), and are executed 64 * through the zvol_task_cb that dispatches the specific operations. Therefore, 65 * these operations are serialized per pool. Consequently, we can be certain 66 * that for a given zvol, there is only one operation at a time in progress. 67 * That is why one can be sure that first, zvol_state_t for a given zvol is 68 * allocated and placed on zvol_state_list, and then other minor operations 69 * for this zvol are going to proceed in the order of issue. 70 * 71 */ 72 73 #include <sys/dataset_kstats.h> 74 #include <sys/dbuf.h> 75 #include <sys/dmu_traverse.h> 76 #include <sys/dsl_dataset.h> 77 #include <sys/dsl_prop.h> 78 #include <sys/dsl_dir.h> 79 #include <sys/zap.h> 80 #include <sys/zfeature.h> 81 #include <sys/zil_impl.h> 82 #include <sys/dmu_tx.h> 83 #include <sys/zio.h> 84 #include <sys/zfs_rlock.h> 85 #include <sys/spa_impl.h> 86 #include <sys/zvol.h> 87 #include <sys/zvol_impl.h> 88 89 unsigned int zvol_inhibit_dev = 0; 90 unsigned int zvol_volmode = ZFS_VOLMODE_GEOM; 91 92 struct hlist_head *zvol_htable; 93 list_t zvol_state_list; 94 krwlock_t zvol_state_lock; 95 const zvol_platform_ops_t *ops; 96 97 typedef enum { 98 ZVOL_ASYNC_REMOVE_MINORS, 99 ZVOL_ASYNC_RENAME_MINORS, 100 ZVOL_ASYNC_SET_SNAPDEV, 101 ZVOL_ASYNC_SET_VOLMODE, 102 ZVOL_ASYNC_MAX 103 } zvol_async_op_t; 104 105 typedef struct { 106 zvol_async_op_t op; 107 char name1[MAXNAMELEN]; 108 char name2[MAXNAMELEN]; 109 uint64_t value; 110 } zvol_task_t; 111 112 uint64_t 113 zvol_name_hash(const char *name) 114 { 115 int i; 116 uint64_t crc = -1ULL; 117 const uint8_t *p = (const uint8_t *)name; 118 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 119 for (i = 0; i < MAXNAMELEN - 1 && *p; i++, p++) { 120 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (*p)) & 0xFF]; 121 } 122 return (crc); 123 } 124 125 /* 126 * Find a zvol_state_t given the name and hash generated by zvol_name_hash. 127 * If found, return with zv_suspend_lock and zv_state_lock taken, otherwise, 128 * return (NULL) without the taking locks. The zv_suspend_lock is always taken 129 * before zv_state_lock. The mode argument indicates the mode (including none) 130 * for zv_suspend_lock to be taken. 131 */ 132 zvol_state_t * 133 zvol_find_by_name_hash(const char *name, uint64_t hash, int mode) 134 { 135 zvol_state_t *zv; 136 struct hlist_node *p = NULL; 137 138 rw_enter(&zvol_state_lock, RW_READER); 139 hlist_for_each(p, ZVOL_HT_HEAD(hash)) { 140 zv = hlist_entry(p, zvol_state_t, zv_hlink); 141 mutex_enter(&zv->zv_state_lock); 142 if (zv->zv_hash == hash && 143 strncmp(zv->zv_name, name, MAXNAMELEN) == 0) { 144 /* 145 * this is the right zvol, take the locks in the 146 * right order 147 */ 148 if (mode != RW_NONE && 149 !rw_tryenter(&zv->zv_suspend_lock, mode)) { 150 mutex_exit(&zv->zv_state_lock); 151 rw_enter(&zv->zv_suspend_lock, mode); 152 mutex_enter(&zv->zv_state_lock); 153 /* 154 * zvol cannot be renamed as we continue 155 * to hold zvol_state_lock 156 */ 157 ASSERT(zv->zv_hash == hash && 158 strncmp(zv->zv_name, name, MAXNAMELEN) 159 == 0); 160 } 161 rw_exit(&zvol_state_lock); 162 return (zv); 163 } 164 mutex_exit(&zv->zv_state_lock); 165 } 166 rw_exit(&zvol_state_lock); 167 168 return (NULL); 169 } 170 171 /* 172 * Find a zvol_state_t given the name. 173 * If found, return with zv_suspend_lock and zv_state_lock taken, otherwise, 174 * return (NULL) without the taking locks. The zv_suspend_lock is always taken 175 * before zv_state_lock. The mode argument indicates the mode (including none) 176 * for zv_suspend_lock to be taken. 177 */ 178 static zvol_state_t * 179 zvol_find_by_name(const char *name, int mode) 180 { 181 return (zvol_find_by_name_hash(name, zvol_name_hash(name), mode)); 182 } 183 184 /* 185 * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation. 186 */ 187 void 188 zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx) 189 { 190 zfs_creat_t *zct = arg; 191 nvlist_t *nvprops = zct->zct_props; 192 int error; 193 uint64_t volblocksize, volsize; 194 195 VERIFY(nvlist_lookup_uint64(nvprops, 196 zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0); 197 if (nvlist_lookup_uint64(nvprops, 198 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0) 199 volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE); 200 201 /* 202 * These properties must be removed from the list so the generic 203 * property setting step won't apply to them. 204 */ 205 VERIFY(nvlist_remove_all(nvprops, 206 zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0); 207 (void) nvlist_remove_all(nvprops, 208 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE)); 209 210 error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize, 211 DMU_OT_NONE, 0, tx); 212 ASSERT(error == 0); 213 214 error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP, 215 DMU_OT_NONE, 0, tx); 216 ASSERT(error == 0); 217 218 error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx); 219 ASSERT(error == 0); 220 } 221 222 /* 223 * ZFS_IOC_OBJSET_STATS entry point. 224 */ 225 int 226 zvol_get_stats(objset_t *os, nvlist_t *nv) 227 { 228 int error; 229 dmu_object_info_t *doi; 230 uint64_t val; 231 232 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val); 233 if (error) 234 return (SET_ERROR(error)); 235 236 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val); 237 doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP); 238 error = dmu_object_info(os, ZVOL_OBJ, doi); 239 240 if (error == 0) { 241 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE, 242 doi->doi_data_block_size); 243 } 244 245 kmem_free(doi, sizeof (dmu_object_info_t)); 246 247 return (SET_ERROR(error)); 248 } 249 250 /* 251 * Sanity check volume size. 252 */ 253 int 254 zvol_check_volsize(uint64_t volsize, uint64_t blocksize) 255 { 256 if (volsize == 0) 257 return (SET_ERROR(EINVAL)); 258 259 if (volsize % blocksize != 0) 260 return (SET_ERROR(EINVAL)); 261 262 #ifdef _ILP32 263 if (volsize - 1 > SPEC_MAXOFFSET_T) 264 return (SET_ERROR(EOVERFLOW)); 265 #endif 266 return (0); 267 } 268 269 /* 270 * Ensure the zap is flushed then inform the VFS of the capacity change. 271 */ 272 static int 273 zvol_update_volsize(uint64_t volsize, objset_t *os) 274 { 275 dmu_tx_t *tx; 276 int error; 277 uint64_t txg; 278 279 tx = dmu_tx_create(os); 280 dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL); 281 dmu_tx_mark_netfree(tx); 282 error = dmu_tx_assign(tx, TXG_WAIT); 283 if (error) { 284 dmu_tx_abort(tx); 285 return (SET_ERROR(error)); 286 } 287 txg = dmu_tx_get_txg(tx); 288 289 error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, 290 &volsize, tx); 291 dmu_tx_commit(tx); 292 293 txg_wait_synced(dmu_objset_pool(os), txg); 294 295 if (error == 0) 296 error = dmu_free_long_range(os, 297 ZVOL_OBJ, volsize, DMU_OBJECT_END); 298 299 return (error); 300 } 301 302 /* 303 * Set ZFS_PROP_VOLSIZE set entry point. Note that modifying the volume 304 * size will result in a udev "change" event being generated. 305 */ 306 int 307 zvol_set_volsize(const char *name, uint64_t volsize) 308 { 309 objset_t *os = NULL; 310 uint64_t readonly; 311 int error; 312 boolean_t owned = B_FALSE; 313 314 error = dsl_prop_get_integer(name, 315 zfs_prop_to_name(ZFS_PROP_READONLY), &readonly, NULL); 316 if (error != 0) 317 return (SET_ERROR(error)); 318 if (readonly) 319 return (SET_ERROR(EROFS)); 320 321 zvol_state_t *zv = zvol_find_by_name(name, RW_READER); 322 323 ASSERT(zv == NULL || (MUTEX_HELD(&zv->zv_state_lock) && 324 RW_READ_HELD(&zv->zv_suspend_lock))); 325 326 if (zv == NULL || zv->zv_objset == NULL) { 327 if (zv != NULL) 328 rw_exit(&zv->zv_suspend_lock); 329 if ((error = dmu_objset_own(name, DMU_OST_ZVOL, B_FALSE, B_TRUE, 330 FTAG, &os)) != 0) { 331 if (zv != NULL) 332 mutex_exit(&zv->zv_state_lock); 333 return (SET_ERROR(error)); 334 } 335 owned = B_TRUE; 336 if (zv != NULL) 337 zv->zv_objset = os; 338 } else { 339 os = zv->zv_objset; 340 } 341 342 dmu_object_info_t *doi = kmem_alloc(sizeof (*doi), KM_SLEEP); 343 344 if ((error = dmu_object_info(os, ZVOL_OBJ, doi)) || 345 (error = zvol_check_volsize(volsize, doi->doi_data_block_size))) 346 goto out; 347 348 error = zvol_update_volsize(volsize, os); 349 if (error == 0 && zv != NULL) { 350 zv->zv_volsize = volsize; 351 zv->zv_changed = 1; 352 } 353 out: 354 kmem_free(doi, sizeof (dmu_object_info_t)); 355 356 if (owned) { 357 dmu_objset_disown(os, B_TRUE, FTAG); 358 if (zv != NULL) 359 zv->zv_objset = NULL; 360 } else { 361 rw_exit(&zv->zv_suspend_lock); 362 } 363 364 if (zv != NULL) 365 mutex_exit(&zv->zv_state_lock); 366 367 if (error == 0 && zv != NULL) 368 ops->zv_update_volsize(zv, volsize); 369 370 return (SET_ERROR(error)); 371 } 372 373 /* 374 * Sanity check volume block size. 375 */ 376 int 377 zvol_check_volblocksize(const char *name, uint64_t volblocksize) 378 { 379 /* Record sizes above 128k need the feature to be enabled */ 380 if (volblocksize > SPA_OLD_MAXBLOCKSIZE) { 381 spa_t *spa; 382 int error; 383 384 if ((error = spa_open(name, &spa, FTAG)) != 0) 385 return (error); 386 387 if (!spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) { 388 spa_close(spa, FTAG); 389 return (SET_ERROR(ENOTSUP)); 390 } 391 392 /* 393 * We don't allow setting the property above 1MB, 394 * unless the tunable has been changed. 395 */ 396 if (volblocksize > zfs_max_recordsize) 397 return (SET_ERROR(EDOM)); 398 399 spa_close(spa, FTAG); 400 } 401 402 if (volblocksize < SPA_MINBLOCKSIZE || 403 volblocksize > SPA_MAXBLOCKSIZE || 404 !ISP2(volblocksize)) 405 return (SET_ERROR(EDOM)); 406 407 return (0); 408 } 409 410 /* 411 * Replay a TX_TRUNCATE ZIL transaction if asked. TX_TRUNCATE is how we 412 * implement DKIOCFREE/free-long-range. 413 */ 414 static int 415 zvol_replay_truncate(void *arg1, void *arg2, boolean_t byteswap) 416 { 417 zvol_state_t *zv = arg1; 418 lr_truncate_t *lr = arg2; 419 uint64_t offset, length; 420 421 if (byteswap) 422 byteswap_uint64_array(lr, sizeof (*lr)); 423 424 offset = lr->lr_offset; 425 length = lr->lr_length; 426 427 dmu_tx_t *tx = dmu_tx_create(zv->zv_objset); 428 dmu_tx_mark_netfree(tx); 429 int error = dmu_tx_assign(tx, TXG_WAIT); 430 if (error != 0) { 431 dmu_tx_abort(tx); 432 } else { 433 zil_replaying(zv->zv_zilog, tx); 434 dmu_tx_commit(tx); 435 error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, 436 length); 437 } 438 439 return (error); 440 } 441 442 /* 443 * Replay a TX_WRITE ZIL transaction that didn't get committed 444 * after a system failure 445 */ 446 static int 447 zvol_replay_write(void *arg1, void *arg2, boolean_t byteswap) 448 { 449 zvol_state_t *zv = arg1; 450 lr_write_t *lr = arg2; 451 objset_t *os = zv->zv_objset; 452 char *data = (char *)(lr + 1); /* data follows lr_write_t */ 453 uint64_t offset, length; 454 dmu_tx_t *tx; 455 int error; 456 457 if (byteswap) 458 byteswap_uint64_array(lr, sizeof (*lr)); 459 460 offset = lr->lr_offset; 461 length = lr->lr_length; 462 463 /* If it's a dmu_sync() block, write the whole block */ 464 if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) { 465 uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr); 466 if (length < blocksize) { 467 offset -= offset % blocksize; 468 length = blocksize; 469 } 470 } 471 472 tx = dmu_tx_create(os); 473 dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length); 474 error = dmu_tx_assign(tx, TXG_WAIT); 475 if (error) { 476 dmu_tx_abort(tx); 477 } else { 478 dmu_write(os, ZVOL_OBJ, offset, length, data, tx); 479 zil_replaying(zv->zv_zilog, tx); 480 dmu_tx_commit(tx); 481 } 482 483 return (error); 484 } 485 486 static int 487 zvol_replay_err(void *arg1, void *arg2, boolean_t byteswap) 488 { 489 return (SET_ERROR(ENOTSUP)); 490 } 491 492 /* 493 * Callback vectors for replaying records. 494 * Only TX_WRITE and TX_TRUNCATE are needed for zvol. 495 */ 496 zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = { 497 zvol_replay_err, /* no such transaction type */ 498 zvol_replay_err, /* TX_CREATE */ 499 zvol_replay_err, /* TX_MKDIR */ 500 zvol_replay_err, /* TX_MKXATTR */ 501 zvol_replay_err, /* TX_SYMLINK */ 502 zvol_replay_err, /* TX_REMOVE */ 503 zvol_replay_err, /* TX_RMDIR */ 504 zvol_replay_err, /* TX_LINK */ 505 zvol_replay_err, /* TX_RENAME */ 506 zvol_replay_write, /* TX_WRITE */ 507 zvol_replay_truncate, /* TX_TRUNCATE */ 508 zvol_replay_err, /* TX_SETATTR */ 509 zvol_replay_err, /* TX_ACL */ 510 zvol_replay_err, /* TX_CREATE_ATTR */ 511 zvol_replay_err, /* TX_CREATE_ACL_ATTR */ 512 zvol_replay_err, /* TX_MKDIR_ACL */ 513 zvol_replay_err, /* TX_MKDIR_ATTR */ 514 zvol_replay_err, /* TX_MKDIR_ACL_ATTR */ 515 zvol_replay_err, /* TX_WRITE2 */ 516 }; 517 518 /* 519 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions. 520 * 521 * We store data in the log buffers if it's small enough. 522 * Otherwise we will later flush the data out via dmu_sync(). 523 */ 524 ssize_t zvol_immediate_write_sz = 32768; 525 526 void 527 zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, uint64_t offset, 528 uint64_t size, int sync) 529 { 530 uint32_t blocksize = zv->zv_volblocksize; 531 zilog_t *zilog = zv->zv_zilog; 532 itx_wr_state_t write_state; 533 uint64_t sz = size; 534 535 if (zil_replaying(zilog, tx)) 536 return; 537 538 if (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT) 539 write_state = WR_INDIRECT; 540 else if (!spa_has_slogs(zilog->zl_spa) && 541 size >= blocksize && blocksize > zvol_immediate_write_sz) 542 write_state = WR_INDIRECT; 543 else if (sync) 544 write_state = WR_COPIED; 545 else 546 write_state = WR_NEED_COPY; 547 548 while (size) { 549 itx_t *itx; 550 lr_write_t *lr; 551 itx_wr_state_t wr_state = write_state; 552 ssize_t len = size; 553 554 if (wr_state == WR_COPIED && size > zil_max_copied_data(zilog)) 555 wr_state = WR_NEED_COPY; 556 else if (wr_state == WR_INDIRECT) 557 len = MIN(blocksize - P2PHASE(offset, blocksize), size); 558 559 itx = zil_itx_create(TX_WRITE, sizeof (*lr) + 560 (wr_state == WR_COPIED ? len : 0)); 561 lr = (lr_write_t *)&itx->itx_lr; 562 if (wr_state == WR_COPIED && dmu_read_by_dnode(zv->zv_dn, 563 offset, len, lr+1, DMU_READ_NO_PREFETCH) != 0) { 564 zil_itx_destroy(itx); 565 itx = zil_itx_create(TX_WRITE, sizeof (*lr)); 566 lr = (lr_write_t *)&itx->itx_lr; 567 wr_state = WR_NEED_COPY; 568 } 569 570 itx->itx_wr_state = wr_state; 571 lr->lr_foid = ZVOL_OBJ; 572 lr->lr_offset = offset; 573 lr->lr_length = len; 574 lr->lr_blkoff = 0; 575 BP_ZERO(&lr->lr_blkptr); 576 577 itx->itx_private = zv; 578 itx->itx_sync = sync; 579 580 (void) zil_itx_assign(zilog, itx, tx); 581 582 offset += len; 583 size -= len; 584 } 585 586 if (write_state == WR_COPIED || write_state == WR_NEED_COPY) { 587 dsl_pool_wrlog_count(zilog->zl_dmu_pool, sz, tx->tx_txg); 588 } 589 } 590 591 /* 592 * Log a DKIOCFREE/free-long-range to the ZIL with TX_TRUNCATE. 593 */ 594 void 595 zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off, uint64_t len, 596 boolean_t sync) 597 { 598 itx_t *itx; 599 lr_truncate_t *lr; 600 zilog_t *zilog = zv->zv_zilog; 601 602 if (zil_replaying(zilog, tx)) 603 return; 604 605 itx = zil_itx_create(TX_TRUNCATE, sizeof (*lr)); 606 lr = (lr_truncate_t *)&itx->itx_lr; 607 lr->lr_foid = ZVOL_OBJ; 608 lr->lr_offset = off; 609 lr->lr_length = len; 610 611 itx->itx_sync = sync; 612 zil_itx_assign(zilog, itx, tx); 613 } 614 615 616 /* ARGSUSED */ 617 static void 618 zvol_get_done(zgd_t *zgd, int error) 619 { 620 if (zgd->zgd_db) 621 dmu_buf_rele(zgd->zgd_db, zgd); 622 623 zfs_rangelock_exit(zgd->zgd_lr); 624 625 kmem_free(zgd, sizeof (zgd_t)); 626 } 627 628 /* 629 * Get data to generate a TX_WRITE intent log record. 630 */ 631 int 632 zvol_get_data(void *arg, uint64_t arg2, lr_write_t *lr, char *buf, 633 struct lwb *lwb, zio_t *zio) 634 { 635 zvol_state_t *zv = arg; 636 uint64_t offset = lr->lr_offset; 637 uint64_t size = lr->lr_length; 638 dmu_buf_t *db; 639 zgd_t *zgd; 640 int error; 641 642 ASSERT3P(lwb, !=, NULL); 643 ASSERT3P(zio, !=, NULL); 644 ASSERT3U(size, !=, 0); 645 646 zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP); 647 zgd->zgd_lwb = lwb; 648 649 /* 650 * Write records come in two flavors: immediate and indirect. 651 * For small writes it's cheaper to store the data with the 652 * log record (immediate); for large writes it's cheaper to 653 * sync the data and get a pointer to it (indirect) so that 654 * we don't have to write the data twice. 655 */ 656 if (buf != NULL) { /* immediate write */ 657 zgd->zgd_lr = zfs_rangelock_enter(&zv->zv_rangelock, offset, 658 size, RL_READER); 659 error = dmu_read_by_dnode(zv->zv_dn, offset, size, buf, 660 DMU_READ_NO_PREFETCH); 661 } else { /* indirect write */ 662 /* 663 * Have to lock the whole block to ensure when it's written out 664 * and its checksum is being calculated that no one can change 665 * the data. Contrarily to zfs_get_data we need not re-check 666 * blocksize after we get the lock because it cannot be changed. 667 */ 668 size = zv->zv_volblocksize; 669 offset = P2ALIGN_TYPED(offset, size, uint64_t); 670 zgd->zgd_lr = zfs_rangelock_enter(&zv->zv_rangelock, offset, 671 size, RL_READER); 672 error = dmu_buf_hold_by_dnode(zv->zv_dn, offset, zgd, &db, 673 DMU_READ_NO_PREFETCH); 674 if (error == 0) { 675 blkptr_t *bp = &lr->lr_blkptr; 676 677 zgd->zgd_db = db; 678 zgd->zgd_bp = bp; 679 680 ASSERT(db != NULL); 681 ASSERT(db->db_offset == offset); 682 ASSERT(db->db_size == size); 683 684 error = dmu_sync(zio, lr->lr_common.lrc_txg, 685 zvol_get_done, zgd); 686 687 if (error == 0) 688 return (0); 689 } 690 } 691 692 zvol_get_done(zgd, error); 693 694 return (SET_ERROR(error)); 695 } 696 697 /* 698 * The zvol_state_t's are inserted into zvol_state_list and zvol_htable. 699 */ 700 701 void 702 zvol_insert(zvol_state_t *zv) 703 { 704 ASSERT(RW_WRITE_HELD(&zvol_state_lock)); 705 list_insert_head(&zvol_state_list, zv); 706 hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash)); 707 } 708 709 /* 710 * Simply remove the zvol from to list of zvols. 711 */ 712 static void 713 zvol_remove(zvol_state_t *zv) 714 { 715 ASSERT(RW_WRITE_HELD(&zvol_state_lock)); 716 list_remove(&zvol_state_list, zv); 717 hlist_del(&zv->zv_hlink); 718 } 719 720 /* 721 * Setup zv after we just own the zv->objset 722 */ 723 static int 724 zvol_setup_zv(zvol_state_t *zv) 725 { 726 uint64_t volsize; 727 int error; 728 uint64_t ro; 729 objset_t *os = zv->zv_objset; 730 731 ASSERT(MUTEX_HELD(&zv->zv_state_lock)); 732 ASSERT(RW_LOCK_HELD(&zv->zv_suspend_lock)); 733 734 zv->zv_zilog = NULL; 735 zv->zv_flags &= ~ZVOL_WRITTEN_TO; 736 737 error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL); 738 if (error) 739 return (SET_ERROR(error)); 740 741 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize); 742 if (error) 743 return (SET_ERROR(error)); 744 745 error = dnode_hold(os, ZVOL_OBJ, zv, &zv->zv_dn); 746 if (error) 747 return (SET_ERROR(error)); 748 749 ops->zv_set_capacity(zv, volsize >> 9); 750 zv->zv_volsize = volsize; 751 752 if (ro || dmu_objset_is_snapshot(os) || 753 !spa_writeable(dmu_objset_spa(os))) { 754 ops->zv_set_disk_ro(zv, 1); 755 zv->zv_flags |= ZVOL_RDONLY; 756 } else { 757 ops->zv_set_disk_ro(zv, 0); 758 zv->zv_flags &= ~ZVOL_RDONLY; 759 } 760 return (0); 761 } 762 763 /* 764 * Shutdown every zv_objset related stuff except zv_objset itself. 765 * The is the reverse of zvol_setup_zv. 766 */ 767 static void 768 zvol_shutdown_zv(zvol_state_t *zv) 769 { 770 ASSERT(MUTEX_HELD(&zv->zv_state_lock) && 771 RW_LOCK_HELD(&zv->zv_suspend_lock)); 772 773 if (zv->zv_flags & ZVOL_WRITTEN_TO) { 774 ASSERT(zv->zv_zilog != NULL); 775 zil_close(zv->zv_zilog); 776 } 777 778 zv->zv_zilog = NULL; 779 780 dnode_rele(zv->zv_dn, zv); 781 zv->zv_dn = NULL; 782 783 /* 784 * Evict cached data. We must write out any dirty data before 785 * disowning the dataset. 786 */ 787 if (zv->zv_flags & ZVOL_WRITTEN_TO) 788 txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0); 789 (void) dmu_objset_evict_dbufs(zv->zv_objset); 790 } 791 792 /* 793 * return the proper tag for rollback and recv 794 */ 795 void * 796 zvol_tag(zvol_state_t *zv) 797 { 798 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock)); 799 return (zv->zv_open_count > 0 ? zv : NULL); 800 } 801 802 /* 803 * Suspend the zvol for recv and rollback. 804 */ 805 zvol_state_t * 806 zvol_suspend(const char *name) 807 { 808 zvol_state_t *zv; 809 810 zv = zvol_find_by_name(name, RW_WRITER); 811 812 if (zv == NULL) 813 return (NULL); 814 815 /* block all I/O, release in zvol_resume. */ 816 ASSERT(MUTEX_HELD(&zv->zv_state_lock)); 817 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock)); 818 819 atomic_inc(&zv->zv_suspend_ref); 820 821 if (zv->zv_open_count > 0) 822 zvol_shutdown_zv(zv); 823 824 /* 825 * do not hold zv_state_lock across suspend/resume to 826 * avoid locking up zvol lookups 827 */ 828 mutex_exit(&zv->zv_state_lock); 829 830 /* zv_suspend_lock is released in zvol_resume() */ 831 return (zv); 832 } 833 834 int 835 zvol_resume(zvol_state_t *zv) 836 { 837 int error = 0; 838 839 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock)); 840 841 mutex_enter(&zv->zv_state_lock); 842 843 if (zv->zv_open_count > 0) { 844 VERIFY0(dmu_objset_hold(zv->zv_name, zv, &zv->zv_objset)); 845 VERIFY3P(zv->zv_objset->os_dsl_dataset->ds_owner, ==, zv); 846 VERIFY(dsl_dataset_long_held(zv->zv_objset->os_dsl_dataset)); 847 dmu_objset_rele(zv->zv_objset, zv); 848 849 error = zvol_setup_zv(zv); 850 } 851 852 mutex_exit(&zv->zv_state_lock); 853 854 rw_exit(&zv->zv_suspend_lock); 855 /* 856 * We need this because we don't hold zvol_state_lock while releasing 857 * zv_suspend_lock. zvol_remove_minors_impl thus cannot check 858 * zv_suspend_lock to determine it is safe to free because rwlock is 859 * not inherent atomic. 860 */ 861 atomic_dec(&zv->zv_suspend_ref); 862 863 return (SET_ERROR(error)); 864 } 865 866 int 867 zvol_first_open(zvol_state_t *zv, boolean_t readonly) 868 { 869 objset_t *os; 870 int error; 871 872 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock)); 873 ASSERT(MUTEX_HELD(&zv->zv_state_lock)); 874 ASSERT(mutex_owned(&spa_namespace_lock)); 875 876 boolean_t ro = (readonly || (strchr(zv->zv_name, '@') != NULL)); 877 error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, ro, B_TRUE, zv, &os); 878 if (error) 879 return (SET_ERROR(error)); 880 881 zv->zv_objset = os; 882 883 error = zvol_setup_zv(zv); 884 if (error) { 885 dmu_objset_disown(os, 1, zv); 886 zv->zv_objset = NULL; 887 } 888 889 return (error); 890 } 891 892 void 893 zvol_last_close(zvol_state_t *zv) 894 { 895 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock)); 896 ASSERT(MUTEX_HELD(&zv->zv_state_lock)); 897 898 zvol_shutdown_zv(zv); 899 900 dmu_objset_disown(zv->zv_objset, 1, zv); 901 zv->zv_objset = NULL; 902 } 903 904 typedef struct minors_job { 905 list_t *list; 906 list_node_t link; 907 /* input */ 908 char *name; 909 /* output */ 910 int error; 911 } minors_job_t; 912 913 /* 914 * Prefetch zvol dnodes for the minors_job 915 */ 916 static void 917 zvol_prefetch_minors_impl(void *arg) 918 { 919 minors_job_t *job = arg; 920 char *dsname = job->name; 921 objset_t *os = NULL; 922 923 job->error = dmu_objset_own(dsname, DMU_OST_ZVOL, B_TRUE, B_TRUE, 924 FTAG, &os); 925 if (job->error == 0) { 926 dmu_prefetch(os, ZVOL_OBJ, 0, 0, 0, ZIO_PRIORITY_SYNC_READ); 927 dmu_objset_disown(os, B_TRUE, FTAG); 928 } 929 } 930 931 /* 932 * Mask errors to continue dmu_objset_find() traversal 933 */ 934 static int 935 zvol_create_snap_minor_cb(const char *dsname, void *arg) 936 { 937 minors_job_t *j = arg; 938 list_t *minors_list = j->list; 939 const char *name = j->name; 940 941 ASSERT0(MUTEX_HELD(&spa_namespace_lock)); 942 943 /* skip the designated dataset */ 944 if (name && strcmp(dsname, name) == 0) 945 return (0); 946 947 /* at this point, the dsname should name a snapshot */ 948 if (strchr(dsname, '@') == 0) { 949 dprintf("zvol_create_snap_minor_cb(): " 950 "%s is not a snapshot name\n", dsname); 951 } else { 952 minors_job_t *job; 953 char *n = kmem_strdup(dsname); 954 if (n == NULL) 955 return (0); 956 957 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP); 958 job->name = n; 959 job->list = minors_list; 960 job->error = 0; 961 list_insert_tail(minors_list, job); 962 /* don't care if dispatch fails, because job->error is 0 */ 963 taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job, 964 TQ_SLEEP); 965 } 966 967 return (0); 968 } 969 970 /* 971 * If spa_keystore_load_wkey() is called for an encrypted zvol, 972 * we need to look for any clones also using the key. This function 973 * is "best effort" - so we just skip over it if there are failures. 974 */ 975 static void 976 zvol_add_clones(const char *dsname, list_t *minors_list) 977 { 978 /* Also check if it has clones */ 979 dsl_dir_t *dd = NULL; 980 dsl_pool_t *dp = NULL; 981 982 if (dsl_pool_hold(dsname, FTAG, &dp) != 0) 983 return; 984 985 if (!spa_feature_is_enabled(dp->dp_spa, 986 SPA_FEATURE_ENCRYPTION)) 987 goto out; 988 989 if (dsl_dir_hold(dp, dsname, FTAG, &dd, NULL) != 0) 990 goto out; 991 992 if (dsl_dir_phys(dd)->dd_clones == 0) 993 goto out; 994 995 zap_cursor_t *zc = kmem_alloc(sizeof (zap_cursor_t), KM_SLEEP); 996 zap_attribute_t *za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP); 997 objset_t *mos = dd->dd_pool->dp_meta_objset; 998 999 for (zap_cursor_init(zc, mos, dsl_dir_phys(dd)->dd_clones); 1000 zap_cursor_retrieve(zc, za) == 0; 1001 zap_cursor_advance(zc)) { 1002 dsl_dataset_t *clone; 1003 minors_job_t *job; 1004 1005 if (dsl_dataset_hold_obj(dd->dd_pool, 1006 za->za_first_integer, FTAG, &clone) == 0) { 1007 1008 char name[ZFS_MAX_DATASET_NAME_LEN]; 1009 dsl_dataset_name(clone, name); 1010 1011 char *n = kmem_strdup(name); 1012 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP); 1013 job->name = n; 1014 job->list = minors_list; 1015 job->error = 0; 1016 list_insert_tail(minors_list, job); 1017 1018 dsl_dataset_rele(clone, FTAG); 1019 } 1020 } 1021 zap_cursor_fini(zc); 1022 kmem_free(za, sizeof (zap_attribute_t)); 1023 kmem_free(zc, sizeof (zap_cursor_t)); 1024 1025 out: 1026 if (dd != NULL) 1027 dsl_dir_rele(dd, FTAG); 1028 if (dp != NULL) 1029 dsl_pool_rele(dp, FTAG); 1030 } 1031 1032 /* 1033 * Mask errors to continue dmu_objset_find() traversal 1034 */ 1035 static int 1036 zvol_create_minors_cb(const char *dsname, void *arg) 1037 { 1038 uint64_t snapdev; 1039 int error; 1040 list_t *minors_list = arg; 1041 1042 ASSERT0(MUTEX_HELD(&spa_namespace_lock)); 1043 1044 error = dsl_prop_get_integer(dsname, "snapdev", &snapdev, NULL); 1045 if (error) 1046 return (0); 1047 1048 /* 1049 * Given the name and the 'snapdev' property, create device minor nodes 1050 * with the linkages to zvols/snapshots as needed. 1051 * If the name represents a zvol, create a minor node for the zvol, then 1052 * check if its snapshots are 'visible', and if so, iterate over the 1053 * snapshots and create device minor nodes for those. 1054 */ 1055 if (strchr(dsname, '@') == 0) { 1056 minors_job_t *job; 1057 char *n = kmem_strdup(dsname); 1058 if (n == NULL) 1059 return (0); 1060 1061 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP); 1062 job->name = n; 1063 job->list = minors_list; 1064 job->error = 0; 1065 list_insert_tail(minors_list, job); 1066 /* don't care if dispatch fails, because job->error is 0 */ 1067 taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job, 1068 TQ_SLEEP); 1069 1070 zvol_add_clones(dsname, minors_list); 1071 1072 if (snapdev == ZFS_SNAPDEV_VISIBLE) { 1073 /* 1074 * traverse snapshots only, do not traverse children, 1075 * and skip the 'dsname' 1076 */ 1077 error = dmu_objset_find(dsname, 1078 zvol_create_snap_minor_cb, (void *)job, 1079 DS_FIND_SNAPSHOTS); 1080 } 1081 } else { 1082 dprintf("zvol_create_minors_cb(): %s is not a zvol name\n", 1083 dsname); 1084 } 1085 1086 return (0); 1087 } 1088 1089 /* 1090 * Create minors for the specified dataset, including children and snapshots. 1091 * Pay attention to the 'snapdev' property and iterate over the snapshots 1092 * only if they are 'visible'. This approach allows one to assure that the 1093 * snapshot metadata is read from disk only if it is needed. 1094 * 1095 * The name can represent a dataset to be recursively scanned for zvols and 1096 * their snapshots, or a single zvol snapshot. If the name represents a 1097 * dataset, the scan is performed in two nested stages: 1098 * - scan the dataset for zvols, and 1099 * - for each zvol, create a minor node, then check if the zvol's snapshots 1100 * are 'visible', and only then iterate over the snapshots if needed 1101 * 1102 * If the name represents a snapshot, a check is performed if the snapshot is 1103 * 'visible' (which also verifies that the parent is a zvol), and if so, 1104 * a minor node for that snapshot is created. 1105 */ 1106 void 1107 zvol_create_minors_recursive(const char *name) 1108 { 1109 list_t minors_list; 1110 minors_job_t *job; 1111 1112 if (zvol_inhibit_dev) 1113 return; 1114 1115 /* 1116 * This is the list for prefetch jobs. Whenever we found a match 1117 * during dmu_objset_find, we insert a minors_job to the list and do 1118 * taskq_dispatch to parallel prefetch zvol dnodes. Note we don't need 1119 * any lock because all list operation is done on the current thread. 1120 * 1121 * We will use this list to do zvol_create_minor_impl after prefetch 1122 * so we don't have to traverse using dmu_objset_find again. 1123 */ 1124 list_create(&minors_list, sizeof (minors_job_t), 1125 offsetof(minors_job_t, link)); 1126 1127 1128 if (strchr(name, '@') != NULL) { 1129 uint64_t snapdev; 1130 1131 int error = dsl_prop_get_integer(name, "snapdev", 1132 &snapdev, NULL); 1133 1134 if (error == 0 && snapdev == ZFS_SNAPDEV_VISIBLE) 1135 (void) ops->zv_create_minor(name); 1136 } else { 1137 fstrans_cookie_t cookie = spl_fstrans_mark(); 1138 (void) dmu_objset_find(name, zvol_create_minors_cb, 1139 &minors_list, DS_FIND_CHILDREN); 1140 spl_fstrans_unmark(cookie); 1141 } 1142 1143 taskq_wait_outstanding(system_taskq, 0); 1144 1145 /* 1146 * Prefetch is completed, we can do zvol_create_minor_impl 1147 * sequentially. 1148 */ 1149 while ((job = list_head(&minors_list)) != NULL) { 1150 list_remove(&minors_list, job); 1151 if (!job->error) 1152 (void) ops->zv_create_minor(job->name); 1153 kmem_strfree(job->name); 1154 kmem_free(job, sizeof (minors_job_t)); 1155 } 1156 1157 list_destroy(&minors_list); 1158 } 1159 1160 void 1161 zvol_create_minor(const char *name) 1162 { 1163 /* 1164 * Note: the dsl_pool_config_lock must not be held. 1165 * Minor node creation needs to obtain the zvol_state_lock. 1166 * zvol_open() obtains the zvol_state_lock and then the dsl pool 1167 * config lock. Therefore, we can't have the config lock now if 1168 * we are going to wait for the zvol_state_lock, because it 1169 * would be a lock order inversion which could lead to deadlock. 1170 */ 1171 1172 if (zvol_inhibit_dev) 1173 return; 1174 1175 if (strchr(name, '@') != NULL) { 1176 uint64_t snapdev; 1177 1178 int error = dsl_prop_get_integer(name, 1179 "snapdev", &snapdev, NULL); 1180 1181 if (error == 0 && snapdev == ZFS_SNAPDEV_VISIBLE) 1182 (void) ops->zv_create_minor(name); 1183 } else { 1184 (void) ops->zv_create_minor(name); 1185 } 1186 } 1187 1188 /* 1189 * Remove minors for specified dataset including children and snapshots. 1190 */ 1191 1192 static void 1193 zvol_free_task(void *arg) 1194 { 1195 ops->zv_free(arg); 1196 } 1197 1198 void 1199 zvol_remove_minors_impl(const char *name) 1200 { 1201 zvol_state_t *zv, *zv_next; 1202 int namelen = ((name) ? strlen(name) : 0); 1203 taskqid_t t; 1204 list_t free_list; 1205 1206 if (zvol_inhibit_dev) 1207 return; 1208 1209 list_create(&free_list, sizeof (zvol_state_t), 1210 offsetof(zvol_state_t, zv_next)); 1211 1212 rw_enter(&zvol_state_lock, RW_WRITER); 1213 1214 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) { 1215 zv_next = list_next(&zvol_state_list, zv); 1216 1217 mutex_enter(&zv->zv_state_lock); 1218 if (name == NULL || strcmp(zv->zv_name, name) == 0 || 1219 (strncmp(zv->zv_name, name, namelen) == 0 && 1220 (zv->zv_name[namelen] == '/' || 1221 zv->zv_name[namelen] == '@'))) { 1222 /* 1223 * By holding zv_state_lock here, we guarantee that no 1224 * one is currently using this zv 1225 */ 1226 1227 /* If in use, leave alone */ 1228 if (zv->zv_open_count > 0 || 1229 atomic_read(&zv->zv_suspend_ref)) { 1230 mutex_exit(&zv->zv_state_lock); 1231 continue; 1232 } 1233 1234 zvol_remove(zv); 1235 1236 /* 1237 * Cleared while holding zvol_state_lock as a writer 1238 * which will prevent zvol_open() from opening it. 1239 */ 1240 ops->zv_clear_private(zv); 1241 1242 /* Drop zv_state_lock before zvol_free() */ 1243 mutex_exit(&zv->zv_state_lock); 1244 1245 /* Try parallel zv_free, if failed do it in place */ 1246 t = taskq_dispatch(system_taskq, zvol_free_task, zv, 1247 TQ_SLEEP); 1248 if (t == TASKQID_INVALID) 1249 list_insert_head(&free_list, zv); 1250 } else { 1251 mutex_exit(&zv->zv_state_lock); 1252 } 1253 } 1254 rw_exit(&zvol_state_lock); 1255 1256 /* Drop zvol_state_lock before calling zvol_free() */ 1257 while ((zv = list_head(&free_list)) != NULL) { 1258 list_remove(&free_list, zv); 1259 ops->zv_free(zv); 1260 } 1261 } 1262 1263 /* Remove minor for this specific volume only */ 1264 static void 1265 zvol_remove_minor_impl(const char *name) 1266 { 1267 zvol_state_t *zv = NULL, *zv_next; 1268 1269 if (zvol_inhibit_dev) 1270 return; 1271 1272 rw_enter(&zvol_state_lock, RW_WRITER); 1273 1274 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) { 1275 zv_next = list_next(&zvol_state_list, zv); 1276 1277 mutex_enter(&zv->zv_state_lock); 1278 if (strcmp(zv->zv_name, name) == 0) { 1279 /* 1280 * By holding zv_state_lock here, we guarantee that no 1281 * one is currently using this zv 1282 */ 1283 1284 /* If in use, leave alone */ 1285 if (zv->zv_open_count > 0 || 1286 atomic_read(&zv->zv_suspend_ref)) { 1287 mutex_exit(&zv->zv_state_lock); 1288 continue; 1289 } 1290 zvol_remove(zv); 1291 1292 ops->zv_clear_private(zv); 1293 mutex_exit(&zv->zv_state_lock); 1294 break; 1295 } else { 1296 mutex_exit(&zv->zv_state_lock); 1297 } 1298 } 1299 1300 /* Drop zvol_state_lock before calling zvol_free() */ 1301 rw_exit(&zvol_state_lock); 1302 1303 if (zv != NULL) 1304 ops->zv_free(zv); 1305 } 1306 1307 /* 1308 * Rename minors for specified dataset including children and snapshots. 1309 */ 1310 static void 1311 zvol_rename_minors_impl(const char *oldname, const char *newname) 1312 { 1313 zvol_state_t *zv, *zv_next; 1314 int oldnamelen, newnamelen; 1315 1316 if (zvol_inhibit_dev) 1317 return; 1318 1319 oldnamelen = strlen(oldname); 1320 newnamelen = strlen(newname); 1321 1322 rw_enter(&zvol_state_lock, RW_READER); 1323 1324 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) { 1325 zv_next = list_next(&zvol_state_list, zv); 1326 1327 mutex_enter(&zv->zv_state_lock); 1328 1329 if (strcmp(zv->zv_name, oldname) == 0) { 1330 ops->zv_rename_minor(zv, newname); 1331 } else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 && 1332 (zv->zv_name[oldnamelen] == '/' || 1333 zv->zv_name[oldnamelen] == '@')) { 1334 char *name = kmem_asprintf("%s%c%s", newname, 1335 zv->zv_name[oldnamelen], 1336 zv->zv_name + oldnamelen + 1); 1337 ops->zv_rename_minor(zv, name); 1338 kmem_strfree(name); 1339 } 1340 1341 mutex_exit(&zv->zv_state_lock); 1342 } 1343 1344 rw_exit(&zvol_state_lock); 1345 } 1346 1347 typedef struct zvol_snapdev_cb_arg { 1348 uint64_t snapdev; 1349 } zvol_snapdev_cb_arg_t; 1350 1351 static int 1352 zvol_set_snapdev_cb(const char *dsname, void *param) 1353 { 1354 zvol_snapdev_cb_arg_t *arg = param; 1355 1356 if (strchr(dsname, '@') == NULL) 1357 return (0); 1358 1359 switch (arg->snapdev) { 1360 case ZFS_SNAPDEV_VISIBLE: 1361 (void) ops->zv_create_minor(dsname); 1362 break; 1363 case ZFS_SNAPDEV_HIDDEN: 1364 (void) zvol_remove_minor_impl(dsname); 1365 break; 1366 } 1367 1368 return (0); 1369 } 1370 1371 static void 1372 zvol_set_snapdev_impl(char *name, uint64_t snapdev) 1373 { 1374 zvol_snapdev_cb_arg_t arg = {snapdev}; 1375 fstrans_cookie_t cookie = spl_fstrans_mark(); 1376 /* 1377 * The zvol_set_snapdev_sync() sets snapdev appropriately 1378 * in the dataset hierarchy. Here, we only scan snapshots. 1379 */ 1380 dmu_objset_find(name, zvol_set_snapdev_cb, &arg, DS_FIND_SNAPSHOTS); 1381 spl_fstrans_unmark(cookie); 1382 } 1383 1384 static void 1385 zvol_set_volmode_impl(char *name, uint64_t volmode) 1386 { 1387 fstrans_cookie_t cookie; 1388 uint64_t old_volmode; 1389 zvol_state_t *zv; 1390 1391 if (strchr(name, '@') != NULL) 1392 return; 1393 1394 /* 1395 * It's unfortunate we need to remove minors before we create new ones: 1396 * this is necessary because our backing gendisk (zvol_state->zv_disk) 1397 * could be different when we set, for instance, volmode from "geom" 1398 * to "dev" (or vice versa). 1399 */ 1400 zv = zvol_find_by_name(name, RW_NONE); 1401 if (zv == NULL && volmode == ZFS_VOLMODE_NONE) 1402 return; 1403 if (zv != NULL) { 1404 old_volmode = zv->zv_volmode; 1405 mutex_exit(&zv->zv_state_lock); 1406 if (old_volmode == volmode) 1407 return; 1408 zvol_wait_close(zv); 1409 } 1410 cookie = spl_fstrans_mark(); 1411 switch (volmode) { 1412 case ZFS_VOLMODE_NONE: 1413 (void) zvol_remove_minor_impl(name); 1414 break; 1415 case ZFS_VOLMODE_GEOM: 1416 case ZFS_VOLMODE_DEV: 1417 (void) zvol_remove_minor_impl(name); 1418 (void) ops->zv_create_minor(name); 1419 break; 1420 case ZFS_VOLMODE_DEFAULT: 1421 (void) zvol_remove_minor_impl(name); 1422 if (zvol_volmode == ZFS_VOLMODE_NONE) 1423 break; 1424 else /* if zvol_volmode is invalid defaults to "geom" */ 1425 (void) ops->zv_create_minor(name); 1426 break; 1427 } 1428 spl_fstrans_unmark(cookie); 1429 } 1430 1431 static zvol_task_t * 1432 zvol_task_alloc(zvol_async_op_t op, const char *name1, const char *name2, 1433 uint64_t value) 1434 { 1435 zvol_task_t *task; 1436 1437 /* Never allow tasks on hidden names. */ 1438 if (name1[0] == '$') 1439 return (NULL); 1440 1441 task = kmem_zalloc(sizeof (zvol_task_t), KM_SLEEP); 1442 task->op = op; 1443 task->value = value; 1444 1445 strlcpy(task->name1, name1, MAXNAMELEN); 1446 if (name2 != NULL) 1447 strlcpy(task->name2, name2, MAXNAMELEN); 1448 1449 return (task); 1450 } 1451 1452 static void 1453 zvol_task_free(zvol_task_t *task) 1454 { 1455 kmem_free(task, sizeof (zvol_task_t)); 1456 } 1457 1458 /* 1459 * The worker thread function performed asynchronously. 1460 */ 1461 static void 1462 zvol_task_cb(void *arg) 1463 { 1464 zvol_task_t *task = arg; 1465 1466 switch (task->op) { 1467 case ZVOL_ASYNC_REMOVE_MINORS: 1468 zvol_remove_minors_impl(task->name1); 1469 break; 1470 case ZVOL_ASYNC_RENAME_MINORS: 1471 zvol_rename_minors_impl(task->name1, task->name2); 1472 break; 1473 case ZVOL_ASYNC_SET_SNAPDEV: 1474 zvol_set_snapdev_impl(task->name1, task->value); 1475 break; 1476 case ZVOL_ASYNC_SET_VOLMODE: 1477 zvol_set_volmode_impl(task->name1, task->value); 1478 break; 1479 default: 1480 VERIFY(0); 1481 break; 1482 } 1483 1484 zvol_task_free(task); 1485 } 1486 1487 typedef struct zvol_set_prop_int_arg { 1488 const char *zsda_name; 1489 uint64_t zsda_value; 1490 zprop_source_t zsda_source; 1491 dmu_tx_t *zsda_tx; 1492 } zvol_set_prop_int_arg_t; 1493 1494 /* 1495 * Sanity check the dataset for safe use by the sync task. No additional 1496 * conditions are imposed. 1497 */ 1498 static int 1499 zvol_set_snapdev_check(void *arg, dmu_tx_t *tx) 1500 { 1501 zvol_set_prop_int_arg_t *zsda = arg; 1502 dsl_pool_t *dp = dmu_tx_pool(tx); 1503 dsl_dir_t *dd; 1504 int error; 1505 1506 error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL); 1507 if (error != 0) 1508 return (error); 1509 1510 dsl_dir_rele(dd, FTAG); 1511 1512 return (error); 1513 } 1514 1515 /* ARGSUSED */ 1516 static int 1517 zvol_set_snapdev_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg) 1518 { 1519 char dsname[MAXNAMELEN]; 1520 zvol_task_t *task; 1521 uint64_t snapdev; 1522 1523 dsl_dataset_name(ds, dsname); 1524 if (dsl_prop_get_int_ds(ds, "snapdev", &snapdev) != 0) 1525 return (0); 1526 task = zvol_task_alloc(ZVOL_ASYNC_SET_SNAPDEV, dsname, NULL, snapdev); 1527 if (task == NULL) 1528 return (0); 1529 1530 (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb, 1531 task, TQ_SLEEP); 1532 return (0); 1533 } 1534 1535 /* 1536 * Traverse all child datasets and apply snapdev appropriately. 1537 * We call dsl_prop_set_sync_impl() here to set the value only on the toplevel 1538 * dataset and read the effective "snapdev" on every child in the callback 1539 * function: this is because the value is not guaranteed to be the same in the 1540 * whole dataset hierarchy. 1541 */ 1542 static void 1543 zvol_set_snapdev_sync(void *arg, dmu_tx_t *tx) 1544 { 1545 zvol_set_prop_int_arg_t *zsda = arg; 1546 dsl_pool_t *dp = dmu_tx_pool(tx); 1547 dsl_dir_t *dd; 1548 dsl_dataset_t *ds; 1549 int error; 1550 1551 VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL)); 1552 zsda->zsda_tx = tx; 1553 1554 error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds); 1555 if (error == 0) { 1556 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_SNAPDEV), 1557 zsda->zsda_source, sizeof (zsda->zsda_value), 1, 1558 &zsda->zsda_value, zsda->zsda_tx); 1559 dsl_dataset_rele(ds, FTAG); 1560 } 1561 dmu_objset_find_dp(dp, dd->dd_object, zvol_set_snapdev_sync_cb, 1562 zsda, DS_FIND_CHILDREN); 1563 1564 dsl_dir_rele(dd, FTAG); 1565 } 1566 1567 int 1568 zvol_set_snapdev(const char *ddname, zprop_source_t source, uint64_t snapdev) 1569 { 1570 zvol_set_prop_int_arg_t zsda; 1571 1572 zsda.zsda_name = ddname; 1573 zsda.zsda_source = source; 1574 zsda.zsda_value = snapdev; 1575 1576 return (dsl_sync_task(ddname, zvol_set_snapdev_check, 1577 zvol_set_snapdev_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE)); 1578 } 1579 1580 /* 1581 * Sanity check the dataset for safe use by the sync task. No additional 1582 * conditions are imposed. 1583 */ 1584 static int 1585 zvol_set_volmode_check(void *arg, dmu_tx_t *tx) 1586 { 1587 zvol_set_prop_int_arg_t *zsda = arg; 1588 dsl_pool_t *dp = dmu_tx_pool(tx); 1589 dsl_dir_t *dd; 1590 int error; 1591 1592 error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL); 1593 if (error != 0) 1594 return (error); 1595 1596 dsl_dir_rele(dd, FTAG); 1597 1598 return (error); 1599 } 1600 1601 /* ARGSUSED */ 1602 static int 1603 zvol_set_volmode_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg) 1604 { 1605 char dsname[MAXNAMELEN]; 1606 zvol_task_t *task; 1607 uint64_t volmode; 1608 1609 dsl_dataset_name(ds, dsname); 1610 if (dsl_prop_get_int_ds(ds, "volmode", &volmode) != 0) 1611 return (0); 1612 task = zvol_task_alloc(ZVOL_ASYNC_SET_VOLMODE, dsname, NULL, volmode); 1613 if (task == NULL) 1614 return (0); 1615 1616 (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb, 1617 task, TQ_SLEEP); 1618 return (0); 1619 } 1620 1621 /* 1622 * Traverse all child datasets and apply volmode appropriately. 1623 * We call dsl_prop_set_sync_impl() here to set the value only on the toplevel 1624 * dataset and read the effective "volmode" on every child in the callback 1625 * function: this is because the value is not guaranteed to be the same in the 1626 * whole dataset hierarchy. 1627 */ 1628 static void 1629 zvol_set_volmode_sync(void *arg, dmu_tx_t *tx) 1630 { 1631 zvol_set_prop_int_arg_t *zsda = arg; 1632 dsl_pool_t *dp = dmu_tx_pool(tx); 1633 dsl_dir_t *dd; 1634 dsl_dataset_t *ds; 1635 int error; 1636 1637 VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL)); 1638 zsda->zsda_tx = tx; 1639 1640 error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds); 1641 if (error == 0) { 1642 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_VOLMODE), 1643 zsda->zsda_source, sizeof (zsda->zsda_value), 1, 1644 &zsda->zsda_value, zsda->zsda_tx); 1645 dsl_dataset_rele(ds, FTAG); 1646 } 1647 1648 dmu_objset_find_dp(dp, dd->dd_object, zvol_set_volmode_sync_cb, 1649 zsda, DS_FIND_CHILDREN); 1650 1651 dsl_dir_rele(dd, FTAG); 1652 } 1653 1654 int 1655 zvol_set_volmode(const char *ddname, zprop_source_t source, uint64_t volmode) 1656 { 1657 zvol_set_prop_int_arg_t zsda; 1658 1659 zsda.zsda_name = ddname; 1660 zsda.zsda_source = source; 1661 zsda.zsda_value = volmode; 1662 1663 return (dsl_sync_task(ddname, zvol_set_volmode_check, 1664 zvol_set_volmode_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE)); 1665 } 1666 1667 void 1668 zvol_remove_minors(spa_t *spa, const char *name, boolean_t async) 1669 { 1670 zvol_task_t *task; 1671 taskqid_t id; 1672 1673 task = zvol_task_alloc(ZVOL_ASYNC_REMOVE_MINORS, name, NULL, ~0ULL); 1674 if (task == NULL) 1675 return; 1676 1677 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP); 1678 if ((async == B_FALSE) && (id != TASKQID_INVALID)) 1679 taskq_wait_id(spa->spa_zvol_taskq, id); 1680 } 1681 1682 void 1683 zvol_rename_minors(spa_t *spa, const char *name1, const char *name2, 1684 boolean_t async) 1685 { 1686 zvol_task_t *task; 1687 taskqid_t id; 1688 1689 task = zvol_task_alloc(ZVOL_ASYNC_RENAME_MINORS, name1, name2, ~0ULL); 1690 if (task == NULL) 1691 return; 1692 1693 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP); 1694 if ((async == B_FALSE) && (id != TASKQID_INVALID)) 1695 taskq_wait_id(spa->spa_zvol_taskq, id); 1696 } 1697 1698 boolean_t 1699 zvol_is_zvol(const char *name) 1700 { 1701 1702 return (ops->zv_is_zvol(name)); 1703 } 1704 1705 void 1706 zvol_register_ops(const zvol_platform_ops_t *zvol_ops) 1707 { 1708 ops = zvol_ops; 1709 } 1710 1711 int 1712 zvol_init_impl(void) 1713 { 1714 int i; 1715 1716 list_create(&zvol_state_list, sizeof (zvol_state_t), 1717 offsetof(zvol_state_t, zv_next)); 1718 rw_init(&zvol_state_lock, NULL, RW_DEFAULT, NULL); 1719 1720 zvol_htable = kmem_alloc(ZVOL_HT_SIZE * sizeof (struct hlist_head), 1721 KM_SLEEP); 1722 for (i = 0; i < ZVOL_HT_SIZE; i++) 1723 INIT_HLIST_HEAD(&zvol_htable[i]); 1724 1725 return (0); 1726 } 1727 1728 void 1729 zvol_fini_impl(void) 1730 { 1731 zvol_remove_minors_impl(NULL); 1732 1733 /* 1734 * The call to "zvol_remove_minors_impl" may dispatch entries to 1735 * the system_taskq, but it doesn't wait for those entries to 1736 * complete before it returns. Thus, we must wait for all of the 1737 * removals to finish, before we can continue. 1738 */ 1739 taskq_wait_outstanding(system_taskq, 0); 1740 1741 kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head)); 1742 list_destroy(&zvol_state_list); 1743 rw_destroy(&zvol_state_lock); 1744 } 1745