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 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * Virtual Device Labels 28 * --------------------- 29 * 30 * The vdev label serves several distinct purposes: 31 * 32 * 1. Uniquely identify this device as part of a ZFS pool and confirm its 33 * identity within the pool. 34 * 35 * 2. Verify that all the devices given in a configuration are present 36 * within the pool. 37 * 38 * 3. Determine the uberblock for the pool. 39 * 40 * 4. In case of an import operation, determine the configuration of the 41 * toplevel vdev of which it is a part. 42 * 43 * 5. If an import operation cannot find all the devices in the pool, 44 * provide enough information to the administrator to determine which 45 * devices are missing. 46 * 47 * It is important to note that while the kernel is responsible for writing the 48 * label, it only consumes the information in the first three cases. The 49 * latter information is only consumed in userland when determining the 50 * configuration to import a pool. 51 * 52 * 53 * Label Organization 54 * ------------------ 55 * 56 * Before describing the contents of the label, it's important to understand how 57 * the labels are written and updated with respect to the uberblock. 58 * 59 * When the pool configuration is altered, either because it was newly created 60 * or a device was added, we want to update all the labels such that we can deal 61 * with fatal failure at any point. To this end, each disk has two labels which 62 * are updated before and after the uberblock is synced. Assuming we have 63 * labels and an uberblock with the following transaction groups: 64 * 65 * L1 UB L2 66 * +------+ +------+ +------+ 67 * | | | | | | 68 * | t10 | | t10 | | t10 | 69 * | | | | | | 70 * +------+ +------+ +------+ 71 * 72 * In this stable state, the labels and the uberblock were all updated within 73 * the same transaction group (10). Each label is mirrored and checksummed, so 74 * that we can detect when we fail partway through writing the label. 75 * 76 * In order to identify which labels are valid, the labels are written in the 77 * following manner: 78 * 79 * 1. For each vdev, update 'L1' to the new label 80 * 2. Update the uberblock 81 * 3. For each vdev, update 'L2' to the new label 82 * 83 * Given arbitrary failure, we can determine the correct label to use based on 84 * the transaction group. If we fail after updating L1 but before updating the 85 * UB, we will notice that L1's transaction group is greater than the uberblock, 86 * so L2 must be valid. If we fail after writing the uberblock but before 87 * writing L2, we will notice that L2's transaction group is less than L1, and 88 * therefore L1 is valid. 89 * 90 * Another added complexity is that not every label is updated when the config 91 * is synced. If we add a single device, we do not want to have to re-write 92 * every label for every device in the pool. This means that both L1 and L2 may 93 * be older than the pool uberblock, because the necessary information is stored 94 * on another vdev. 95 * 96 * 97 * On-disk Format 98 * -------------- 99 * 100 * The vdev label consists of two distinct parts, and is wrapped within the 101 * vdev_label_t structure. The label includes 8k of padding to permit legacy 102 * VTOC disk labels, but is otherwise ignored. 103 * 104 * The first half of the label is a packed nvlist which contains pool wide 105 * properties, per-vdev properties, and configuration information. It is 106 * described in more detail below. 107 * 108 * The latter half of the label consists of a redundant array of uberblocks. 109 * These uberblocks are updated whenever a transaction group is committed, 110 * or when the configuration is updated. When a pool is loaded, we scan each 111 * vdev for the 'best' uberblock. 112 * 113 * 114 * Configuration Information 115 * ------------------------- 116 * 117 * The nvlist describing the pool and vdev contains the following elements: 118 * 119 * version ZFS on-disk version 120 * name Pool name 121 * state Pool state 122 * txg Transaction group in which this label was written 123 * pool_guid Unique identifier for this pool 124 * vdev_tree An nvlist describing vdev tree. 125 * 126 * Each leaf device label also contains the following: 127 * 128 * top_guid Unique ID for top-level vdev in which this is contained 129 * guid Unique ID for the leaf vdev 130 * 131 * The 'vs' configuration follows the format described in 'spa_config.c'. 132 */ 133 134 #include <sys/zfs_context.h> 135 #include <sys/spa.h> 136 #include <sys/spa_impl.h> 137 #include <sys/dmu.h> 138 #include <sys/zap.h> 139 #include <sys/vdev.h> 140 #include <sys/vdev_impl.h> 141 #include <sys/uberblock_impl.h> 142 #include <sys/metaslab.h> 143 #include <sys/zio.h> 144 #include <sys/fs/zfs.h> 145 146 /* 147 * Basic routines to read and write from a vdev label. 148 * Used throughout the rest of this file. 149 */ 150 uint64_t 151 vdev_label_offset(uint64_t psize, int l, uint64_t offset) 152 { 153 ASSERT(offset < sizeof (vdev_label_t)); 154 ASSERT(P2PHASE_TYPED(psize, sizeof (vdev_label_t), uint64_t) == 0); 155 156 return (offset + l * sizeof (vdev_label_t) + (l < VDEV_LABELS / 2 ? 157 0 : psize - VDEV_LABELS * sizeof (vdev_label_t))); 158 } 159 160 /* 161 * Returns back the vdev label associated with the passed in offset. 162 */ 163 int 164 vdev_label_number(uint64_t psize, uint64_t offset) 165 { 166 int l; 167 168 if (offset >= psize - VDEV_LABEL_END_SIZE) { 169 offset -= psize - VDEV_LABEL_END_SIZE; 170 offset += (VDEV_LABELS / 2) * sizeof (vdev_label_t); 171 } 172 l = offset / sizeof (vdev_label_t); 173 return (l < VDEV_LABELS ? l : -1); 174 } 175 176 static void 177 vdev_label_read(zio_t *zio, vdev_t *vd, int l, void *buf, uint64_t offset, 178 uint64_t size, zio_done_func_t *done, void *private, int flags) 179 { 180 ASSERT(spa_config_held(zio->io_spa, SCL_STATE_ALL, RW_WRITER) == 181 SCL_STATE_ALL); 182 ASSERT(flags & ZIO_FLAG_CONFIG_WRITER); 183 184 zio_nowait(zio_read_phys(zio, vd, 185 vdev_label_offset(vd->vdev_psize, l, offset), 186 size, buf, ZIO_CHECKSUM_LABEL, done, private, 187 ZIO_PRIORITY_SYNC_READ, flags, B_TRUE)); 188 } 189 190 static void 191 vdev_label_write(zio_t *zio, vdev_t *vd, int l, void *buf, uint64_t offset, 192 uint64_t size, zio_done_func_t *done, void *private, int flags) 193 { 194 ASSERT(spa_config_held(zio->io_spa, SCL_ALL, RW_WRITER) == SCL_ALL || 195 (spa_config_held(zio->io_spa, SCL_CONFIG | SCL_STATE, RW_READER) == 196 (SCL_CONFIG | SCL_STATE) && 197 dsl_pool_sync_context(spa_get_dsl(zio->io_spa)))); 198 ASSERT(flags & ZIO_FLAG_CONFIG_WRITER); 199 200 zio_nowait(zio_write_phys(zio, vd, 201 vdev_label_offset(vd->vdev_psize, l, offset), 202 size, buf, ZIO_CHECKSUM_LABEL, done, private, 203 ZIO_PRIORITY_SYNC_WRITE, flags, B_TRUE)); 204 } 205 206 /* 207 * Generate the nvlist representing this vdev's config. 208 */ 209 nvlist_t * 210 vdev_config_generate(spa_t *spa, vdev_t *vd, boolean_t getstats, 211 boolean_t isspare, boolean_t isl2cache) 212 { 213 nvlist_t *nv = NULL; 214 215 VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0); 216 217 VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_TYPE, 218 vd->vdev_ops->vdev_op_type) == 0); 219 if (!isspare && !isl2cache) 220 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ID, vd->vdev_id) 221 == 0); 222 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_GUID, vd->vdev_guid) == 0); 223 224 if (vd->vdev_path != NULL) 225 VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_PATH, 226 vd->vdev_path) == 0); 227 228 if (vd->vdev_devid != NULL) 229 VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_DEVID, 230 vd->vdev_devid) == 0); 231 232 if (vd->vdev_physpath != NULL) 233 VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_PHYS_PATH, 234 vd->vdev_physpath) == 0); 235 236 if (vd->vdev_nparity != 0) { 237 ASSERT(strcmp(vd->vdev_ops->vdev_op_type, 238 VDEV_TYPE_RAIDZ) == 0); 239 240 /* 241 * Make sure someone hasn't managed to sneak a fancy new vdev 242 * into a crufty old storage pool. 243 */ 244 ASSERT(vd->vdev_nparity == 1 || 245 (vd->vdev_nparity == 2 && 246 spa_version(spa) >= SPA_VERSION_RAID6)); 247 248 /* 249 * Note that we'll add the nparity tag even on storage pools 250 * that only support a single parity device -- older software 251 * will just ignore it. 252 */ 253 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_NPARITY, 254 vd->vdev_nparity) == 0); 255 } 256 257 if (vd->vdev_wholedisk != -1ULL) 258 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK, 259 vd->vdev_wholedisk) == 0); 260 261 if (vd->vdev_not_present) 262 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT, 1) == 0); 263 264 if (vd->vdev_isspare) 265 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_IS_SPARE, 1) == 0); 266 267 if (!isspare && !isl2cache && vd == vd->vdev_top) { 268 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_METASLAB_ARRAY, 269 vd->vdev_ms_array) == 0); 270 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_METASLAB_SHIFT, 271 vd->vdev_ms_shift) == 0); 272 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ASHIFT, 273 vd->vdev_ashift) == 0); 274 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_ASIZE, 275 vd->vdev_asize) == 0); 276 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_IS_LOG, 277 vd->vdev_islog) == 0); 278 } 279 280 if (vd->vdev_dtl.smo_object != 0) 281 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_DTL, 282 vd->vdev_dtl.smo_object) == 0); 283 284 if (getstats) { 285 vdev_stat_t vs; 286 vdev_get_stats(vd, &vs); 287 VERIFY(nvlist_add_uint64_array(nv, ZPOOL_CONFIG_STATS, 288 (uint64_t *)&vs, sizeof (vs) / sizeof (uint64_t)) == 0); 289 } 290 291 if (!vd->vdev_ops->vdev_op_leaf) { 292 nvlist_t **child; 293 int c; 294 295 child = kmem_alloc(vd->vdev_children * sizeof (nvlist_t *), 296 KM_SLEEP); 297 298 for (c = 0; c < vd->vdev_children; c++) 299 child[c] = vdev_config_generate(spa, vd->vdev_child[c], 300 getstats, isspare, isl2cache); 301 302 VERIFY(nvlist_add_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN, 303 child, vd->vdev_children) == 0); 304 305 for (c = 0; c < vd->vdev_children; c++) 306 nvlist_free(child[c]); 307 308 kmem_free(child, vd->vdev_children * sizeof (nvlist_t *)); 309 310 } else { 311 if (vd->vdev_offline && !vd->vdev_tmpoffline) 312 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_OFFLINE, 313 B_TRUE) == 0); 314 if (vd->vdev_faulted) 315 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_FAULTED, 316 B_TRUE) == 0); 317 if (vd->vdev_degraded) 318 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_DEGRADED, 319 B_TRUE) == 0); 320 if (vd->vdev_removed) 321 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_REMOVED, 322 B_TRUE) == 0); 323 if (vd->vdev_unspare) 324 VERIFY(nvlist_add_uint64(nv, ZPOOL_CONFIG_UNSPARE, 325 B_TRUE) == 0); 326 } 327 328 return (nv); 329 } 330 331 nvlist_t * 332 vdev_label_read_config(vdev_t *vd) 333 { 334 spa_t *spa = vd->vdev_spa; 335 nvlist_t *config = NULL; 336 vdev_phys_t *vp; 337 zio_t *zio; 338 int flags = 339 ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE; 340 341 ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL); 342 343 if (!vdev_readable(vd)) 344 return (NULL); 345 346 vp = zio_buf_alloc(sizeof (vdev_phys_t)); 347 348 for (int l = 0; l < VDEV_LABELS; l++) { 349 350 zio = zio_root(spa, NULL, NULL, flags); 351 352 vdev_label_read(zio, vd, l, vp, 353 offsetof(vdev_label_t, vl_vdev_phys), 354 sizeof (vdev_phys_t), NULL, NULL, flags); 355 356 if (zio_wait(zio) == 0 && 357 nvlist_unpack(vp->vp_nvlist, sizeof (vp->vp_nvlist), 358 &config, 0) == 0) 359 break; 360 361 if (config != NULL) { 362 nvlist_free(config); 363 config = NULL; 364 } 365 } 366 367 zio_buf_free(vp, sizeof (vdev_phys_t)); 368 369 return (config); 370 } 371 372 /* 373 * Determine if a device is in use. The 'spare_guid' parameter will be filled 374 * in with the device guid if this spare is active elsewhere on the system. 375 */ 376 static boolean_t 377 vdev_inuse(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason, 378 uint64_t *spare_guid, uint64_t *l2cache_guid) 379 { 380 spa_t *spa = vd->vdev_spa; 381 uint64_t state, pool_guid, device_guid, txg, spare_pool; 382 uint64_t vdtxg = 0; 383 nvlist_t *label; 384 385 if (spare_guid) 386 *spare_guid = 0ULL; 387 if (l2cache_guid) 388 *l2cache_guid = 0ULL; 389 390 /* 391 * Read the label, if any, and perform some basic sanity checks. 392 */ 393 if ((label = vdev_label_read_config(vd)) == NULL) 394 return (B_FALSE); 395 396 (void) nvlist_lookup_uint64(label, ZPOOL_CONFIG_CREATE_TXG, 397 &vdtxg); 398 399 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE, 400 &state) != 0 || 401 nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, 402 &device_guid) != 0) { 403 nvlist_free(label); 404 return (B_FALSE); 405 } 406 407 if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE && 408 (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_GUID, 409 &pool_guid) != 0 || 410 nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_TXG, 411 &txg) != 0)) { 412 nvlist_free(label); 413 return (B_FALSE); 414 } 415 416 nvlist_free(label); 417 418 /* 419 * Check to see if this device indeed belongs to the pool it claims to 420 * be a part of. The only way this is allowed is if the device is a hot 421 * spare (which we check for later on). 422 */ 423 if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE && 424 !spa_guid_exists(pool_guid, device_guid) && 425 !spa_spare_exists(device_guid, NULL, NULL) && 426 !spa_l2cache_exists(device_guid, NULL)) 427 return (B_FALSE); 428 429 /* 430 * If the transaction group is zero, then this an initialized (but 431 * unused) label. This is only an error if the create transaction 432 * on-disk is the same as the one we're using now, in which case the 433 * user has attempted to add the same vdev multiple times in the same 434 * transaction. 435 */ 436 if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE && 437 txg == 0 && vdtxg == crtxg) 438 return (B_TRUE); 439 440 /* 441 * Check to see if this is a spare device. We do an explicit check for 442 * spa_has_spare() here because it may be on our pending list of spares 443 * to add. We also check if it is an l2cache device. 444 */ 445 if (spa_spare_exists(device_guid, &spare_pool, NULL) || 446 spa_has_spare(spa, device_guid)) { 447 if (spare_guid) 448 *spare_guid = device_guid; 449 450 switch (reason) { 451 case VDEV_LABEL_CREATE: 452 case VDEV_LABEL_L2CACHE: 453 return (B_TRUE); 454 455 case VDEV_LABEL_REPLACE: 456 return (!spa_has_spare(spa, device_guid) || 457 spare_pool != 0ULL); 458 459 case VDEV_LABEL_SPARE: 460 return (spa_has_spare(spa, device_guid)); 461 } 462 } 463 464 /* 465 * Check to see if this is an l2cache device. 466 */ 467 if (spa_l2cache_exists(device_guid, NULL)) 468 return (B_TRUE); 469 470 /* 471 * If the device is marked ACTIVE, then this device is in use by another 472 * pool on the system. 473 */ 474 return (state == POOL_STATE_ACTIVE); 475 } 476 477 /* 478 * Initialize a vdev label. We check to make sure each leaf device is not in 479 * use, and writable. We put down an initial label which we will later 480 * overwrite with a complete label. Note that it's important to do this 481 * sequentially, not in parallel, so that we catch cases of multiple use of the 482 * same leaf vdev in the vdev we're creating -- e.g. mirroring a disk with 483 * itself. 484 */ 485 int 486 vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason) 487 { 488 spa_t *spa = vd->vdev_spa; 489 nvlist_t *label; 490 vdev_phys_t *vp; 491 vdev_boot_header_t *vb; 492 uberblock_t *ub; 493 zio_t *zio; 494 char *buf; 495 size_t buflen; 496 int error; 497 uint64_t spare_guid, l2cache_guid; 498 int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL; 499 500 ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL); 501 502 for (int c = 0; c < vd->vdev_children; c++) 503 if ((error = vdev_label_init(vd->vdev_child[c], 504 crtxg, reason)) != 0) 505 return (error); 506 507 if (!vd->vdev_ops->vdev_op_leaf) 508 return (0); 509 510 /* 511 * Dead vdevs cannot be initialized. 512 */ 513 if (vdev_is_dead(vd)) 514 return (EIO); 515 516 /* 517 * Determine if the vdev is in use. 518 */ 519 if (reason != VDEV_LABEL_REMOVE && 520 vdev_inuse(vd, crtxg, reason, &spare_guid, &l2cache_guid)) 521 return (EBUSY); 522 523 ASSERT(reason != VDEV_LABEL_REMOVE || 524 vdev_inuse(vd, crtxg, reason, NULL, NULL)); 525 526 /* 527 * If this is a request to add or replace a spare or l2cache device 528 * that is in use elsewhere on the system, then we must update the 529 * guid (which was initialized to a random value) to reflect the 530 * actual GUID (which is shared between multiple pools). 531 */ 532 if (reason != VDEV_LABEL_REMOVE && reason != VDEV_LABEL_L2CACHE && 533 spare_guid != 0ULL) { 534 ASSERT(vd->vdev_parent == NULL); 535 536 vd->vdev_guid = vd->vdev_guid_sum = spare_guid; 537 538 /* 539 * If this is a replacement, then we want to fallthrough to the 540 * rest of the code. If we're adding a spare, then it's already 541 * labeled appropriately and we can just return. 542 */ 543 if (reason == VDEV_LABEL_SPARE) 544 return (0); 545 ASSERT(reason == VDEV_LABEL_REPLACE); 546 } 547 548 if (reason != VDEV_LABEL_REMOVE && reason != VDEV_LABEL_SPARE && 549 l2cache_guid != 0ULL) { 550 ASSERT(vd->vdev_parent == NULL); 551 552 vd->vdev_guid = vd->vdev_guid_sum = l2cache_guid; 553 554 /* 555 * If this is a replacement, then we want to fallthrough to the 556 * rest of the code. If we're adding an l2cache, then it's 557 * already labeled appropriately and we can just return. 558 */ 559 if (reason == VDEV_LABEL_L2CACHE) 560 return (0); 561 ASSERT(reason == VDEV_LABEL_REPLACE); 562 } 563 564 /* 565 * Initialize its label. 566 */ 567 vp = zio_buf_alloc(sizeof (vdev_phys_t)); 568 bzero(vp, sizeof (vdev_phys_t)); 569 570 /* 571 * Generate a label describing the pool and our top-level vdev. 572 * We mark it as being from txg 0 to indicate that it's not 573 * really part of an active pool just yet. The labels will 574 * be written again with a meaningful txg by spa_sync(). 575 */ 576 if (reason == VDEV_LABEL_SPARE || 577 (reason == VDEV_LABEL_REMOVE && vd->vdev_isspare)) { 578 /* 579 * For inactive hot spares, we generate a special label that 580 * identifies as a mutually shared hot spare. We write the 581 * label if we are adding a hot spare, or if we are removing an 582 * active hot spare (in which case we want to revert the 583 * labels). 584 */ 585 VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0); 586 587 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION, 588 spa_version(spa)) == 0); 589 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_POOL_STATE, 590 POOL_STATE_SPARE) == 0); 591 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_GUID, 592 vd->vdev_guid) == 0); 593 } else if (reason == VDEV_LABEL_L2CACHE || 594 (reason == VDEV_LABEL_REMOVE && vd->vdev_isl2cache)) { 595 /* 596 * For level 2 ARC devices, add a special label. 597 */ 598 VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0); 599 600 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION, 601 spa_version(spa)) == 0); 602 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_POOL_STATE, 603 POOL_STATE_L2CACHE) == 0); 604 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_GUID, 605 vd->vdev_guid) == 0); 606 } else { 607 label = spa_config_generate(spa, vd, 0ULL, B_FALSE); 608 609 /* 610 * Add our creation time. This allows us to detect multiple 611 * vdev uses as described above, and automatically expires if we 612 * fail. 613 */ 614 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_CREATE_TXG, 615 crtxg) == 0); 616 } 617 618 buf = vp->vp_nvlist; 619 buflen = sizeof (vp->vp_nvlist); 620 621 error = nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP); 622 if (error != 0) { 623 nvlist_free(label); 624 zio_buf_free(vp, sizeof (vdev_phys_t)); 625 /* EFAULT means nvlist_pack ran out of room */ 626 return (error == EFAULT ? ENAMETOOLONG : EINVAL); 627 } 628 629 /* 630 * Initialize boot block header. 631 */ 632 vb = zio_buf_alloc(sizeof (vdev_boot_header_t)); 633 bzero(vb, sizeof (vdev_boot_header_t)); 634 vb->vb_magic = VDEV_BOOT_MAGIC; 635 vb->vb_version = VDEV_BOOT_VERSION; 636 vb->vb_offset = VDEV_BOOT_OFFSET; 637 vb->vb_size = VDEV_BOOT_SIZE; 638 639 /* 640 * Initialize uberblock template. 641 */ 642 ub = zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)); 643 bzero(ub, VDEV_UBERBLOCK_SIZE(vd)); 644 *ub = spa->spa_uberblock; 645 ub->ub_txg = 0; 646 647 /* 648 * Write everything in parallel. 649 */ 650 zio = zio_root(spa, NULL, NULL, flags); 651 652 for (int l = 0; l < VDEV_LABELS; l++) { 653 654 vdev_label_write(zio, vd, l, vp, 655 offsetof(vdev_label_t, vl_vdev_phys), 656 sizeof (vdev_phys_t), NULL, NULL, flags); 657 658 vdev_label_write(zio, vd, l, vb, 659 offsetof(vdev_label_t, vl_boot_header), 660 sizeof (vdev_boot_header_t), NULL, NULL, flags); 661 662 for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) { 663 vdev_label_write(zio, vd, l, ub, 664 VDEV_UBERBLOCK_OFFSET(vd, n), 665 VDEV_UBERBLOCK_SIZE(vd), NULL, NULL, flags); 666 } 667 } 668 669 error = zio_wait(zio); 670 671 nvlist_free(label); 672 zio_buf_free(ub, VDEV_UBERBLOCK_SIZE(vd)); 673 zio_buf_free(vb, sizeof (vdev_boot_header_t)); 674 zio_buf_free(vp, sizeof (vdev_phys_t)); 675 676 /* 677 * If this vdev hasn't been previously identified as a spare, then we 678 * mark it as such only if a) we are labeling it as a spare, or b) it 679 * exists as a spare elsewhere in the system. Do the same for 680 * level 2 ARC devices. 681 */ 682 if (error == 0 && !vd->vdev_isspare && 683 (reason == VDEV_LABEL_SPARE || 684 spa_spare_exists(vd->vdev_guid, NULL, NULL))) 685 spa_spare_add(vd); 686 687 if (error == 0 && !vd->vdev_isl2cache && 688 (reason == VDEV_LABEL_L2CACHE || 689 spa_l2cache_exists(vd->vdev_guid, NULL))) 690 spa_l2cache_add(vd); 691 692 return (error); 693 } 694 695 /* 696 * ========================================================================== 697 * uberblock load/sync 698 * ========================================================================== 699 */ 700 701 /* 702 * Consider the following situation: txg is safely synced to disk. We've 703 * written the first uberblock for txg + 1, and then we lose power. When we 704 * come back up, we fail to see the uberblock for txg + 1 because, say, 705 * it was on a mirrored device and the replica to which we wrote txg + 1 706 * is now offline. If we then make some changes and sync txg + 1, and then 707 * the missing replica comes back, then for a new seconds we'll have two 708 * conflicting uberblocks on disk with the same txg. The solution is simple: 709 * among uberblocks with equal txg, choose the one with the latest timestamp. 710 */ 711 static int 712 vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2) 713 { 714 if (ub1->ub_txg < ub2->ub_txg) 715 return (-1); 716 if (ub1->ub_txg > ub2->ub_txg) 717 return (1); 718 719 if (ub1->ub_timestamp < ub2->ub_timestamp) 720 return (-1); 721 if (ub1->ub_timestamp > ub2->ub_timestamp) 722 return (1); 723 724 return (0); 725 } 726 727 static void 728 vdev_uberblock_load_done(zio_t *zio) 729 { 730 zio_t *rio = zio->io_private; 731 uberblock_t *ub = zio->io_data; 732 uberblock_t *ubbest = rio->io_private; 733 734 ASSERT3U(zio->io_size, ==, VDEV_UBERBLOCK_SIZE(zio->io_vd)); 735 736 if (zio->io_error == 0 && uberblock_verify(ub) == 0) { 737 mutex_enter(&rio->io_lock); 738 if (vdev_uberblock_compare(ub, ubbest) > 0) 739 *ubbest = *ub; 740 mutex_exit(&rio->io_lock); 741 } 742 743 zio_buf_free(zio->io_data, zio->io_size); 744 } 745 746 void 747 vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest) 748 { 749 spa_t *spa = vd->vdev_spa; 750 vdev_t *rvd = spa->spa_root_vdev; 751 int flags = 752 ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE; 753 754 if (vd == rvd) { 755 ASSERT(zio == NULL); 756 spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER); 757 zio = zio_root(spa, NULL, ubbest, flags); 758 bzero(ubbest, sizeof (uberblock_t)); 759 } 760 761 ASSERT(zio != NULL); 762 763 for (int c = 0; c < vd->vdev_children; c++) 764 vdev_uberblock_load(zio, vd->vdev_child[c], ubbest); 765 766 if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) { 767 for (int l = 0; l < VDEV_LABELS; l++) { 768 for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) { 769 vdev_label_read(zio, vd, l, 770 zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)), 771 VDEV_UBERBLOCK_OFFSET(vd, n), 772 VDEV_UBERBLOCK_SIZE(vd), 773 vdev_uberblock_load_done, zio, flags); 774 } 775 } 776 } 777 778 if (vd == rvd) { 779 (void) zio_wait(zio); 780 spa_config_exit(spa, SCL_ALL, FTAG); 781 } 782 } 783 784 /* 785 * On success, increment root zio's count of good writes. 786 * We only get credit for writes to known-visible vdevs; see spa_vdev_add(). 787 */ 788 static void 789 vdev_uberblock_sync_done(zio_t *zio) 790 { 791 uint64_t *good_writes = zio->io_private; 792 793 if (zio->io_error == 0 && zio->io_vd->vdev_top->vdev_ms_array != 0) 794 atomic_add_64(good_writes, 1); 795 } 796 797 /* 798 * Write the uberblock to all labels of all leaves of the specified vdev. 799 */ 800 static void 801 vdev_uberblock_sync(zio_t *zio, uberblock_t *ub, vdev_t *vd, int flags) 802 { 803 uberblock_t *ubbuf; 804 int n; 805 806 for (int c = 0; c < vd->vdev_children; c++) 807 vdev_uberblock_sync(zio, ub, vd->vdev_child[c], flags); 808 809 if (!vd->vdev_ops->vdev_op_leaf) 810 return; 811 812 if (!vdev_writeable(vd)) 813 return; 814 815 n = ub->ub_txg & (VDEV_UBERBLOCK_COUNT(vd) - 1); 816 817 ubbuf = zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)); 818 bzero(ubbuf, VDEV_UBERBLOCK_SIZE(vd)); 819 *ubbuf = *ub; 820 821 for (int l = 0; l < VDEV_LABELS; l++) 822 vdev_label_write(zio, vd, l, ubbuf, 823 VDEV_UBERBLOCK_OFFSET(vd, n), VDEV_UBERBLOCK_SIZE(vd), 824 vdev_uberblock_sync_done, zio->io_private, 825 flags | ZIO_FLAG_DONT_PROPAGATE); 826 827 zio_buf_free(ubbuf, VDEV_UBERBLOCK_SIZE(vd)); 828 } 829 830 int 831 vdev_uberblock_sync_list(vdev_t **svd, int svdcount, uberblock_t *ub, int flags) 832 { 833 spa_t *spa = svd[0]->vdev_spa; 834 zio_t *zio; 835 uint64_t good_writes = 0; 836 837 zio = zio_root(spa, NULL, &good_writes, flags); 838 839 for (int v = 0; v < svdcount; v++) 840 vdev_uberblock_sync(zio, ub, svd[v], flags); 841 842 (void) zio_wait(zio); 843 844 /* 845 * Flush the uberblocks to disk. This ensures that the odd labels 846 * are no longer needed (because the new uberblocks and the even 847 * labels are safely on disk), so it is safe to overwrite them. 848 */ 849 zio = zio_root(spa, NULL, NULL, flags); 850 851 for (int v = 0; v < svdcount; v++) 852 zio_flush(zio, svd[v]); 853 854 (void) zio_wait(zio); 855 856 return (good_writes >= 1 ? 0 : EIO); 857 } 858 859 /* 860 * On success, increment the count of good writes for our top-level vdev. 861 */ 862 static void 863 vdev_label_sync_done(zio_t *zio) 864 { 865 uint64_t *good_writes = zio->io_private; 866 867 if (zio->io_error == 0) 868 atomic_add_64(good_writes, 1); 869 } 870 871 /* 872 * If there weren't enough good writes, indicate failure to the parent. 873 */ 874 static void 875 vdev_label_sync_top_done(zio_t *zio) 876 { 877 uint64_t *good_writes = zio->io_private; 878 879 if (*good_writes == 0) 880 zio->io_error = EIO; 881 882 kmem_free(good_writes, sizeof (uint64_t)); 883 } 884 885 /* 886 * We ignore errors for log and cache devices, simply free the private data. 887 */ 888 static void 889 vdev_label_sync_ignore_done(zio_t *zio) 890 { 891 kmem_free(zio->io_private, sizeof (uint64_t)); 892 } 893 894 /* 895 * Write all even or odd labels to all leaves of the specified vdev. 896 */ 897 static void 898 vdev_label_sync(zio_t *zio, vdev_t *vd, int l, uint64_t txg, int flags) 899 { 900 nvlist_t *label; 901 vdev_phys_t *vp; 902 char *buf; 903 size_t buflen; 904 905 for (int c = 0; c < vd->vdev_children; c++) 906 vdev_label_sync(zio, vd->vdev_child[c], l, txg, flags); 907 908 if (!vd->vdev_ops->vdev_op_leaf) 909 return; 910 911 if (!vdev_writeable(vd)) 912 return; 913 914 /* 915 * Generate a label describing the top-level config to which we belong. 916 */ 917 label = spa_config_generate(vd->vdev_spa, vd, txg, B_FALSE); 918 919 vp = zio_buf_alloc(sizeof (vdev_phys_t)); 920 bzero(vp, sizeof (vdev_phys_t)); 921 922 buf = vp->vp_nvlist; 923 buflen = sizeof (vp->vp_nvlist); 924 925 if (nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP) == 0) { 926 for (; l < VDEV_LABELS; l += 2) { 927 vdev_label_write(zio, vd, l, vp, 928 offsetof(vdev_label_t, vl_vdev_phys), 929 sizeof (vdev_phys_t), 930 vdev_label_sync_done, zio->io_private, 931 flags | ZIO_FLAG_DONT_PROPAGATE); 932 } 933 } 934 935 zio_buf_free(vp, sizeof (vdev_phys_t)); 936 nvlist_free(label); 937 } 938 939 int 940 vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags) 941 { 942 list_t *dl = &spa->spa_config_dirty_list; 943 vdev_t *vd; 944 zio_t *zio; 945 int error; 946 947 /* 948 * Write the new labels to disk. 949 */ 950 zio = zio_root(spa, NULL, NULL, flags); 951 952 for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd)) { 953 uint64_t *good_writes = kmem_zalloc(sizeof (uint64_t), 954 KM_SLEEP); 955 zio_t *vio = zio_null(zio, spa, 956 (vd->vdev_islog || vd->vdev_aux != NULL) ? 957 vdev_label_sync_ignore_done : vdev_label_sync_top_done, 958 good_writes, flags); 959 vdev_label_sync(vio, vd, l, txg, flags); 960 zio_nowait(vio); 961 } 962 963 error = zio_wait(zio); 964 965 /* 966 * Flush the new labels to disk. 967 */ 968 zio = zio_root(spa, NULL, NULL, flags); 969 970 for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd)) 971 zio_flush(zio, vd); 972 973 (void) zio_wait(zio); 974 975 return (error); 976 } 977 978 /* 979 * Sync the uberblock and any changes to the vdev configuration. 980 * 981 * The order of operations is carefully crafted to ensure that 982 * if the system panics or loses power at any time, the state on disk 983 * is still transactionally consistent. The in-line comments below 984 * describe the failure semantics at each stage. 985 * 986 * Moreover, vdev_config_sync() is designed to be idempotent: if it fails 987 * at any time, you can just call it again, and it will resume its work. 988 */ 989 int 990 vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg) 991 { 992 spa_t *spa = svd[0]->vdev_spa; 993 uberblock_t *ub = &spa->spa_uberblock; 994 vdev_t *vd; 995 zio_t *zio; 996 int error; 997 int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL; 998 999 ASSERT(ub->ub_txg <= txg); 1000 1001 /* 1002 * If this isn't a resync due to I/O errors, 1003 * and nothing changed in this transaction group, 1004 * and the vdev configuration hasn't changed, 1005 * then there's nothing to do. 1006 */ 1007 if (ub->ub_txg < txg && 1008 uberblock_update(ub, spa->spa_root_vdev, txg) == B_FALSE && 1009 list_is_empty(&spa->spa_config_dirty_list)) 1010 return (0); 1011 1012 if (txg > spa_freeze_txg(spa)) 1013 return (0); 1014 1015 ASSERT(txg <= spa->spa_final_txg); 1016 1017 /* 1018 * Flush the write cache of every disk that's been written to 1019 * in this transaction group. This ensures that all blocks 1020 * written in this txg will be committed to stable storage 1021 * before any uberblock that references them. 1022 */ 1023 zio = zio_root(spa, NULL, NULL, flags); 1024 1025 for (vd = txg_list_head(&spa->spa_vdev_txg_list, TXG_CLEAN(txg)); vd; 1026 vd = txg_list_next(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg))) 1027 zio_flush(zio, vd); 1028 1029 (void) zio_wait(zio); 1030 1031 /* 1032 * Sync out the even labels (L0, L2) for every dirty vdev. If the 1033 * system dies in the middle of this process, that's OK: all of the 1034 * even labels that made it to disk will be newer than any uberblock, 1035 * and will therefore be considered invalid. The odd labels (L1, L3), 1036 * which have not yet been touched, will still be valid. We flush 1037 * the new labels to disk to ensure that all even-label updates 1038 * are committed to stable storage before the uberblock update. 1039 */ 1040 if ((error = vdev_label_sync_list(spa, 0, txg, flags)) != 0) 1041 return (error); 1042 1043 /* 1044 * Sync the uberblocks to all vdevs in svd[]. 1045 * If the system dies in the middle of this step, there are two cases 1046 * to consider, and the on-disk state is consistent either way: 1047 * 1048 * (1) If none of the new uberblocks made it to disk, then the 1049 * previous uberblock will be the newest, and the odd labels 1050 * (which had not yet been touched) will be valid with respect 1051 * to that uberblock. 1052 * 1053 * (2) If one or more new uberblocks made it to disk, then they 1054 * will be the newest, and the even labels (which had all 1055 * been successfully committed) will be valid with respect 1056 * to the new uberblocks. 1057 */ 1058 if ((error = vdev_uberblock_sync_list(svd, svdcount, ub, flags)) != 0) 1059 return (error); 1060 1061 /* 1062 * Sync out odd labels for every dirty vdev. If the system dies 1063 * in the middle of this process, the even labels and the new 1064 * uberblocks will suffice to open the pool. The next time 1065 * the pool is opened, the first thing we'll do -- before any 1066 * user data is modified -- is mark every vdev dirty so that 1067 * all labels will be brought up to date. We flush the new labels 1068 * to disk to ensure that all odd-label updates are committed to 1069 * stable storage before the next transaction group begins. 1070 */ 1071 return (vdev_label_sync_list(spa, 1, txg, flags)); 1072 } 1073