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 uint64_t guid_delta = spare_guid - vd->vdev_guid; 535 536 vd->vdev_guid += guid_delta; 537 538 for (vdev_t *pvd = vd; pvd != NULL; pvd = pvd->vdev_parent) 539 pvd->vdev_guid_sum += guid_delta; 540 541 /* 542 * If this is a replacement, then we want to fallthrough to the 543 * rest of the code. If we're adding a spare, then it's already 544 * labeled appropriately and we can just return. 545 */ 546 if (reason == VDEV_LABEL_SPARE) 547 return (0); 548 ASSERT(reason == VDEV_LABEL_REPLACE); 549 } 550 551 if (reason != VDEV_LABEL_REMOVE && reason != VDEV_LABEL_SPARE && 552 l2cache_guid != 0ULL) { 553 uint64_t guid_delta = l2cache_guid - vd->vdev_guid; 554 555 vd->vdev_guid += guid_delta; 556 557 for (vdev_t *pvd = vd; pvd != NULL; pvd = pvd->vdev_parent) 558 pvd->vdev_guid_sum += guid_delta; 559 560 /* 561 * If this is a replacement, then we want to fallthrough to the 562 * rest of the code. If we're adding an l2cache, then it's 563 * already labeled appropriately and we can just return. 564 */ 565 if (reason == VDEV_LABEL_L2CACHE) 566 return (0); 567 ASSERT(reason == VDEV_LABEL_REPLACE); 568 } 569 570 /* 571 * Initialize its label. 572 */ 573 vp = zio_buf_alloc(sizeof (vdev_phys_t)); 574 bzero(vp, sizeof (vdev_phys_t)); 575 576 /* 577 * Generate a label describing the pool and our top-level vdev. 578 * We mark it as being from txg 0 to indicate that it's not 579 * really part of an active pool just yet. The labels will 580 * be written again with a meaningful txg by spa_sync(). 581 */ 582 if (reason == VDEV_LABEL_SPARE || 583 (reason == VDEV_LABEL_REMOVE && vd->vdev_isspare)) { 584 /* 585 * For inactive hot spares, we generate a special label that 586 * identifies as a mutually shared hot spare. We write the 587 * label if we are adding a hot spare, or if we are removing an 588 * active hot spare (in which case we want to revert the 589 * labels). 590 */ 591 VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0); 592 593 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION, 594 spa_version(spa)) == 0); 595 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_POOL_STATE, 596 POOL_STATE_SPARE) == 0); 597 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_GUID, 598 vd->vdev_guid) == 0); 599 } else if (reason == VDEV_LABEL_L2CACHE || 600 (reason == VDEV_LABEL_REMOVE && vd->vdev_isl2cache)) { 601 /* 602 * For level 2 ARC devices, add a special label. 603 */ 604 VERIFY(nvlist_alloc(&label, NV_UNIQUE_NAME, KM_SLEEP) == 0); 605 606 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_VERSION, 607 spa_version(spa)) == 0); 608 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_POOL_STATE, 609 POOL_STATE_L2CACHE) == 0); 610 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_GUID, 611 vd->vdev_guid) == 0); 612 } else { 613 label = spa_config_generate(spa, vd, 0ULL, B_FALSE); 614 615 /* 616 * Add our creation time. This allows us to detect multiple 617 * vdev uses as described above, and automatically expires if we 618 * fail. 619 */ 620 VERIFY(nvlist_add_uint64(label, ZPOOL_CONFIG_CREATE_TXG, 621 crtxg) == 0); 622 } 623 624 buf = vp->vp_nvlist; 625 buflen = sizeof (vp->vp_nvlist); 626 627 error = nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP); 628 if (error != 0) { 629 nvlist_free(label); 630 zio_buf_free(vp, sizeof (vdev_phys_t)); 631 /* EFAULT means nvlist_pack ran out of room */ 632 return (error == EFAULT ? ENAMETOOLONG : EINVAL); 633 } 634 635 /* 636 * Initialize boot block header. 637 */ 638 vb = zio_buf_alloc(sizeof (vdev_boot_header_t)); 639 bzero(vb, sizeof (vdev_boot_header_t)); 640 vb->vb_magic = VDEV_BOOT_MAGIC; 641 vb->vb_version = VDEV_BOOT_VERSION; 642 vb->vb_offset = VDEV_BOOT_OFFSET; 643 vb->vb_size = VDEV_BOOT_SIZE; 644 645 /* 646 * Initialize uberblock template. 647 */ 648 ub = zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)); 649 bzero(ub, VDEV_UBERBLOCK_SIZE(vd)); 650 *ub = spa->spa_uberblock; 651 ub->ub_txg = 0; 652 653 /* 654 * Write everything in parallel. 655 */ 656 zio = zio_root(spa, NULL, NULL, flags); 657 658 for (int l = 0; l < VDEV_LABELS; l++) { 659 660 vdev_label_write(zio, vd, l, vp, 661 offsetof(vdev_label_t, vl_vdev_phys), 662 sizeof (vdev_phys_t), NULL, NULL, flags); 663 664 vdev_label_write(zio, vd, l, vb, 665 offsetof(vdev_label_t, vl_boot_header), 666 sizeof (vdev_boot_header_t), NULL, NULL, flags); 667 668 for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) { 669 vdev_label_write(zio, vd, l, ub, 670 VDEV_UBERBLOCK_OFFSET(vd, n), 671 VDEV_UBERBLOCK_SIZE(vd), NULL, NULL, flags); 672 } 673 } 674 675 error = zio_wait(zio); 676 677 nvlist_free(label); 678 zio_buf_free(ub, VDEV_UBERBLOCK_SIZE(vd)); 679 zio_buf_free(vb, sizeof (vdev_boot_header_t)); 680 zio_buf_free(vp, sizeof (vdev_phys_t)); 681 682 /* 683 * If this vdev hasn't been previously identified as a spare, then we 684 * mark it as such only if a) we are labeling it as a spare, or b) it 685 * exists as a spare elsewhere in the system. Do the same for 686 * level 2 ARC devices. 687 */ 688 if (error == 0 && !vd->vdev_isspare && 689 (reason == VDEV_LABEL_SPARE || 690 spa_spare_exists(vd->vdev_guid, NULL, NULL))) 691 spa_spare_add(vd); 692 693 if (error == 0 && !vd->vdev_isl2cache && 694 (reason == VDEV_LABEL_L2CACHE || 695 spa_l2cache_exists(vd->vdev_guid, NULL))) 696 spa_l2cache_add(vd); 697 698 return (error); 699 } 700 701 /* 702 * ========================================================================== 703 * uberblock load/sync 704 * ========================================================================== 705 */ 706 707 /* 708 * Consider the following situation: txg is safely synced to disk. We've 709 * written the first uberblock for txg + 1, and then we lose power. When we 710 * come back up, we fail to see the uberblock for txg + 1 because, say, 711 * it was on a mirrored device and the replica to which we wrote txg + 1 712 * is now offline. If we then make some changes and sync txg + 1, and then 713 * the missing replica comes back, then for a new seconds we'll have two 714 * conflicting uberblocks on disk with the same txg. The solution is simple: 715 * among uberblocks with equal txg, choose the one with the latest timestamp. 716 */ 717 static int 718 vdev_uberblock_compare(uberblock_t *ub1, uberblock_t *ub2) 719 { 720 if (ub1->ub_txg < ub2->ub_txg) 721 return (-1); 722 if (ub1->ub_txg > ub2->ub_txg) 723 return (1); 724 725 if (ub1->ub_timestamp < ub2->ub_timestamp) 726 return (-1); 727 if (ub1->ub_timestamp > ub2->ub_timestamp) 728 return (1); 729 730 return (0); 731 } 732 733 static void 734 vdev_uberblock_load_done(zio_t *zio) 735 { 736 zio_t *rio = zio->io_private; 737 uberblock_t *ub = zio->io_data; 738 uberblock_t *ubbest = rio->io_private; 739 740 ASSERT3U(zio->io_size, ==, VDEV_UBERBLOCK_SIZE(zio->io_vd)); 741 742 if (zio->io_error == 0 && uberblock_verify(ub) == 0) { 743 mutex_enter(&rio->io_lock); 744 if (vdev_uberblock_compare(ub, ubbest) > 0) 745 *ubbest = *ub; 746 mutex_exit(&rio->io_lock); 747 } 748 749 zio_buf_free(zio->io_data, zio->io_size); 750 } 751 752 void 753 vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest) 754 { 755 spa_t *spa = vd->vdev_spa; 756 vdev_t *rvd = spa->spa_root_vdev; 757 int flags = 758 ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE; 759 760 if (vd == rvd) { 761 ASSERT(zio == NULL); 762 spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER); 763 zio = zio_root(spa, NULL, ubbest, flags); 764 bzero(ubbest, sizeof (uberblock_t)); 765 } 766 767 ASSERT(zio != NULL); 768 769 for (int c = 0; c < vd->vdev_children; c++) 770 vdev_uberblock_load(zio, vd->vdev_child[c], ubbest); 771 772 if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) { 773 for (int l = 0; l < VDEV_LABELS; l++) { 774 for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) { 775 vdev_label_read(zio, vd, l, 776 zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)), 777 VDEV_UBERBLOCK_OFFSET(vd, n), 778 VDEV_UBERBLOCK_SIZE(vd), 779 vdev_uberblock_load_done, zio, flags); 780 } 781 } 782 } 783 784 if (vd == rvd) { 785 (void) zio_wait(zio); 786 spa_config_exit(spa, SCL_ALL, FTAG); 787 } 788 } 789 790 /* 791 * On success, increment root zio's count of good writes. 792 * We only get credit for writes to known-visible vdevs; see spa_vdev_add(). 793 */ 794 static void 795 vdev_uberblock_sync_done(zio_t *zio) 796 { 797 uint64_t *good_writes = zio->io_private; 798 799 if (zio->io_error == 0 && zio->io_vd->vdev_top->vdev_ms_array != 0) 800 atomic_add_64(good_writes, 1); 801 } 802 803 /* 804 * Write the uberblock to all labels of all leaves of the specified vdev. 805 */ 806 static void 807 vdev_uberblock_sync(zio_t *zio, uberblock_t *ub, vdev_t *vd, int flags) 808 { 809 uberblock_t *ubbuf; 810 int n; 811 812 for (int c = 0; c < vd->vdev_children; c++) 813 vdev_uberblock_sync(zio, ub, vd->vdev_child[c], flags); 814 815 if (!vd->vdev_ops->vdev_op_leaf) 816 return; 817 818 if (!vdev_writeable(vd)) 819 return; 820 821 n = ub->ub_txg & (VDEV_UBERBLOCK_COUNT(vd) - 1); 822 823 ubbuf = zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)); 824 bzero(ubbuf, VDEV_UBERBLOCK_SIZE(vd)); 825 *ubbuf = *ub; 826 827 for (int l = 0; l < VDEV_LABELS; l++) 828 vdev_label_write(zio, vd, l, ubbuf, 829 VDEV_UBERBLOCK_OFFSET(vd, n), VDEV_UBERBLOCK_SIZE(vd), 830 vdev_uberblock_sync_done, zio->io_private, 831 flags | ZIO_FLAG_DONT_PROPAGATE); 832 833 zio_buf_free(ubbuf, VDEV_UBERBLOCK_SIZE(vd)); 834 } 835 836 int 837 vdev_uberblock_sync_list(vdev_t **svd, int svdcount, uberblock_t *ub, int flags) 838 { 839 spa_t *spa = svd[0]->vdev_spa; 840 zio_t *zio; 841 uint64_t good_writes = 0; 842 843 zio = zio_root(spa, NULL, &good_writes, flags); 844 845 for (int v = 0; v < svdcount; v++) 846 vdev_uberblock_sync(zio, ub, svd[v], flags); 847 848 (void) zio_wait(zio); 849 850 /* 851 * Flush the uberblocks to disk. This ensures that the odd labels 852 * are no longer needed (because the new uberblocks and the even 853 * labels are safely on disk), so it is safe to overwrite them. 854 */ 855 zio = zio_root(spa, NULL, NULL, flags); 856 857 for (int v = 0; v < svdcount; v++) 858 zio_flush(zio, svd[v]); 859 860 (void) zio_wait(zio); 861 862 return (good_writes >= 1 ? 0 : EIO); 863 } 864 865 /* 866 * On success, increment the count of good writes for our top-level vdev. 867 */ 868 static void 869 vdev_label_sync_done(zio_t *zio) 870 { 871 uint64_t *good_writes = zio->io_private; 872 873 if (zio->io_error == 0) 874 atomic_add_64(good_writes, 1); 875 } 876 877 /* 878 * If there weren't enough good writes, indicate failure to the parent. 879 */ 880 static void 881 vdev_label_sync_top_done(zio_t *zio) 882 { 883 uint64_t *good_writes = zio->io_private; 884 885 if (*good_writes == 0) 886 zio->io_error = EIO; 887 888 kmem_free(good_writes, sizeof (uint64_t)); 889 } 890 891 /* 892 * We ignore errors for log and cache devices, simply free the private data. 893 */ 894 static void 895 vdev_label_sync_ignore_done(zio_t *zio) 896 { 897 kmem_free(zio->io_private, sizeof (uint64_t)); 898 } 899 900 /* 901 * Write all even or odd labels to all leaves of the specified vdev. 902 */ 903 static void 904 vdev_label_sync(zio_t *zio, vdev_t *vd, int l, uint64_t txg, int flags) 905 { 906 nvlist_t *label; 907 vdev_phys_t *vp; 908 char *buf; 909 size_t buflen; 910 911 for (int c = 0; c < vd->vdev_children; c++) 912 vdev_label_sync(zio, vd->vdev_child[c], l, txg, flags); 913 914 if (!vd->vdev_ops->vdev_op_leaf) 915 return; 916 917 if (!vdev_writeable(vd)) 918 return; 919 920 /* 921 * Generate a label describing the top-level config to which we belong. 922 */ 923 label = spa_config_generate(vd->vdev_spa, vd, txg, B_FALSE); 924 925 vp = zio_buf_alloc(sizeof (vdev_phys_t)); 926 bzero(vp, sizeof (vdev_phys_t)); 927 928 buf = vp->vp_nvlist; 929 buflen = sizeof (vp->vp_nvlist); 930 931 if (nvlist_pack(label, &buf, &buflen, NV_ENCODE_XDR, KM_SLEEP) == 0) { 932 for (; l < VDEV_LABELS; l += 2) { 933 vdev_label_write(zio, vd, l, vp, 934 offsetof(vdev_label_t, vl_vdev_phys), 935 sizeof (vdev_phys_t), 936 vdev_label_sync_done, zio->io_private, 937 flags | ZIO_FLAG_DONT_PROPAGATE); 938 } 939 } 940 941 zio_buf_free(vp, sizeof (vdev_phys_t)); 942 nvlist_free(label); 943 } 944 945 int 946 vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags) 947 { 948 list_t *dl = &spa->spa_config_dirty_list; 949 vdev_t *vd; 950 zio_t *zio; 951 int error; 952 953 /* 954 * Write the new labels to disk. 955 */ 956 zio = zio_root(spa, NULL, NULL, flags); 957 958 for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd)) { 959 uint64_t *good_writes = kmem_zalloc(sizeof (uint64_t), 960 KM_SLEEP); 961 zio_t *vio = zio_null(zio, spa, 962 (vd->vdev_islog || vd->vdev_aux != NULL) ? 963 vdev_label_sync_ignore_done : vdev_label_sync_top_done, 964 good_writes, flags); 965 vdev_label_sync(vio, vd, l, txg, flags); 966 zio_nowait(vio); 967 } 968 969 error = zio_wait(zio); 970 971 /* 972 * Flush the new labels to disk. 973 */ 974 zio = zio_root(spa, NULL, NULL, flags); 975 976 for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd)) 977 zio_flush(zio, vd); 978 979 (void) zio_wait(zio); 980 981 return (error); 982 } 983 984 /* 985 * Sync the uberblock and any changes to the vdev configuration. 986 * 987 * The order of operations is carefully crafted to ensure that 988 * if the system panics or loses power at any time, the state on disk 989 * is still transactionally consistent. The in-line comments below 990 * describe the failure semantics at each stage. 991 * 992 * Moreover, vdev_config_sync() is designed to be idempotent: if it fails 993 * at any time, you can just call it again, and it will resume its work. 994 */ 995 int 996 vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg) 997 { 998 spa_t *spa = svd[0]->vdev_spa; 999 uberblock_t *ub = &spa->spa_uberblock; 1000 vdev_t *vd; 1001 zio_t *zio; 1002 int error; 1003 int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL; 1004 1005 ASSERT(ub->ub_txg <= txg); 1006 1007 /* 1008 * If this isn't a resync due to I/O errors, 1009 * and nothing changed in this transaction group, 1010 * and the vdev configuration hasn't changed, 1011 * then there's nothing to do. 1012 */ 1013 if (ub->ub_txg < txg && 1014 uberblock_update(ub, spa->spa_root_vdev, txg) == B_FALSE && 1015 list_is_empty(&spa->spa_config_dirty_list)) 1016 return (0); 1017 1018 if (txg > spa_freeze_txg(spa)) 1019 return (0); 1020 1021 ASSERT(txg <= spa->spa_final_txg); 1022 1023 /* 1024 * Flush the write cache of every disk that's been written to 1025 * in this transaction group. This ensures that all blocks 1026 * written in this txg will be committed to stable storage 1027 * before any uberblock that references them. 1028 */ 1029 zio = zio_root(spa, NULL, NULL, flags); 1030 1031 for (vd = txg_list_head(&spa->spa_vdev_txg_list, TXG_CLEAN(txg)); vd; 1032 vd = txg_list_next(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg))) 1033 zio_flush(zio, vd); 1034 1035 (void) zio_wait(zio); 1036 1037 /* 1038 * Sync out the even labels (L0, L2) for every dirty vdev. If the 1039 * system dies in the middle of this process, that's OK: all of the 1040 * even labels that made it to disk will be newer than any uberblock, 1041 * and will therefore be considered invalid. The odd labels (L1, L3), 1042 * which have not yet been touched, will still be valid. We flush 1043 * the new labels to disk to ensure that all even-label updates 1044 * are committed to stable storage before the uberblock update. 1045 */ 1046 if ((error = vdev_label_sync_list(spa, 0, txg, flags)) != 0) 1047 return (error); 1048 1049 /* 1050 * Sync the uberblocks to all vdevs in svd[]. 1051 * If the system dies in the middle of this step, there are two cases 1052 * to consider, and the on-disk state is consistent either way: 1053 * 1054 * (1) If none of the new uberblocks made it to disk, then the 1055 * previous uberblock will be the newest, and the odd labels 1056 * (which had not yet been touched) will be valid with respect 1057 * to that uberblock. 1058 * 1059 * (2) If one or more new uberblocks made it to disk, then they 1060 * will be the newest, and the even labels (which had all 1061 * been successfully committed) will be valid with respect 1062 * to the new uberblocks. 1063 */ 1064 if ((error = vdev_uberblock_sync_list(svd, svdcount, ub, flags)) != 0) 1065 return (error); 1066 1067 /* 1068 * Sync out odd labels for every dirty vdev. If the system dies 1069 * in the middle of this process, the even labels and the new 1070 * uberblocks will suffice to open the pool. The next time 1071 * the pool is opened, the first thing we'll do -- before any 1072 * user data is modified -- is mark every vdev dirty so that 1073 * all labels will be brought up to date. We flush the new labels 1074 * to disk to ensure that all odd-label updates are committed to 1075 * stable storage before the next transaction group begins. 1076 */ 1077 return (vdev_label_sync_list(spa, 1, txg, flags)); 1078 } 1079