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 2010 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * Copyright (c) 2012, 2014 by Delphix. All rights reserved. 28 */ 29 30 #include <sys/zfs_context.h> 31 #include <sys/spa.h> 32 #include <sys/vdev_impl.h> 33 #include <sys/zio.h> 34 #include <sys/fs/zfs.h> 35 36 /* 37 * Virtual device vector for mirroring. 38 */ 39 40 typedef struct mirror_child { 41 vdev_t *mc_vd; 42 uint64_t mc_offset; 43 int mc_error; 44 uint8_t mc_tried; 45 uint8_t mc_skipped; 46 uint8_t mc_speculative; 47 } mirror_child_t; 48 49 typedef struct mirror_map { 50 int mm_children; 51 int mm_replacing; 52 int mm_preferred; 53 int mm_root; 54 mirror_child_t mm_child[1]; 55 } mirror_map_t; 56 57 int vdev_mirror_shift = 21; 58 59 static void 60 vdev_mirror_map_free(zio_t *zio) 61 { 62 mirror_map_t *mm = zio->io_vsd; 63 64 kmem_free(mm, offsetof(mirror_map_t, mm_child[mm->mm_children])); 65 } 66 67 static const zio_vsd_ops_t vdev_mirror_vsd_ops = { 68 vdev_mirror_map_free, 69 zio_vsd_default_cksum_report 70 }; 71 72 static mirror_map_t * 73 vdev_mirror_map_alloc(zio_t *zio) 74 { 75 mirror_map_t *mm = NULL; 76 mirror_child_t *mc; 77 vdev_t *vd = zio->io_vd; 78 int c, d; 79 80 if (vd == NULL) { 81 dva_t *dva = zio->io_bp->blk_dva; 82 spa_t *spa = zio->io_spa; 83 84 c = BP_GET_NDVAS(zio->io_bp); 85 86 mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP); 87 mm->mm_children = c; 88 mm->mm_replacing = B_FALSE; 89 mm->mm_preferred = spa_get_random(c); 90 mm->mm_root = B_TRUE; 91 92 /* 93 * Check the other, lower-index DVAs to see if they're on 94 * the same vdev as the child we picked. If they are, use 95 * them since they are likely to have been allocated from 96 * the primary metaslab in use at the time, and hence are 97 * more likely to have locality with single-copy data. 98 */ 99 for (c = mm->mm_preferred, d = c - 1; d >= 0; d--) { 100 if (DVA_GET_VDEV(&dva[d]) == DVA_GET_VDEV(&dva[c])) 101 mm->mm_preferred = d; 102 } 103 104 for (c = 0; c < mm->mm_children; c++) { 105 mc = &mm->mm_child[c]; 106 107 mc->mc_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[c])); 108 mc->mc_offset = DVA_GET_OFFSET(&dva[c]); 109 } 110 } else { 111 c = vd->vdev_children; 112 113 mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP); 114 mm->mm_children = c; 115 mm->mm_replacing = (vd->vdev_ops == &vdev_replacing_ops || 116 vd->vdev_ops == &vdev_spare_ops); 117 mm->mm_preferred = mm->mm_replacing ? 0 : 118 (zio->io_offset >> vdev_mirror_shift) % c; 119 mm->mm_root = B_FALSE; 120 121 for (c = 0; c < mm->mm_children; c++) { 122 mc = &mm->mm_child[c]; 123 mc->mc_vd = vd->vdev_child[c]; 124 mc->mc_offset = zio->io_offset; 125 } 126 } 127 128 zio->io_vsd = mm; 129 zio->io_vsd_ops = &vdev_mirror_vsd_ops; 130 return (mm); 131 } 132 133 static int 134 vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize, 135 uint64_t *ashift) 136 { 137 int numerrors = 0; 138 int lasterror = 0; 139 140 if (vd->vdev_children == 0) { 141 vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL; 142 return (SET_ERROR(EINVAL)); 143 } 144 145 vdev_open_children(vd); 146 147 for (int c = 0; c < vd->vdev_children; c++) { 148 vdev_t *cvd = vd->vdev_child[c]; 149 150 if (cvd->vdev_open_error) { 151 lasterror = cvd->vdev_open_error; 152 numerrors++; 153 continue; 154 } 155 156 *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1; 157 *max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1; 158 *ashift = MAX(*ashift, cvd->vdev_ashift); 159 } 160 161 if (numerrors == vd->vdev_children) { 162 vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS; 163 return (lasterror); 164 } 165 166 return (0); 167 } 168 169 static void 170 vdev_mirror_close(vdev_t *vd) 171 { 172 for (int c = 0; c < vd->vdev_children; c++) 173 vdev_close(vd->vdev_child[c]); 174 } 175 176 static void 177 vdev_mirror_child_done(zio_t *zio) 178 { 179 mirror_child_t *mc = zio->io_private; 180 181 mc->mc_error = zio->io_error; 182 mc->mc_tried = 1; 183 mc->mc_skipped = 0; 184 } 185 186 static void 187 vdev_mirror_scrub_done(zio_t *zio) 188 { 189 mirror_child_t *mc = zio->io_private; 190 191 if (zio->io_error == 0) { 192 zio_t *pio; 193 194 mutex_enter(&zio->io_lock); 195 while ((pio = zio_walk_parents(zio)) != NULL) { 196 mutex_enter(&pio->io_lock); 197 ASSERT3U(zio->io_size, >=, pio->io_size); 198 bcopy(zio->io_data, pio->io_data, pio->io_size); 199 mutex_exit(&pio->io_lock); 200 } 201 mutex_exit(&zio->io_lock); 202 } 203 204 zio_buf_free(zio->io_data, zio->io_size); 205 206 mc->mc_error = zio->io_error; 207 mc->mc_tried = 1; 208 mc->mc_skipped = 0; 209 } 210 211 /* 212 * Try to find a child whose DTL doesn't contain the block we want to read. 213 * If we can't, try the read on any vdev we haven't already tried. 214 */ 215 static int 216 vdev_mirror_child_select(zio_t *zio) 217 { 218 mirror_map_t *mm = zio->io_vsd; 219 mirror_child_t *mc; 220 uint64_t txg = zio->io_txg; 221 int i, c; 222 223 ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg); 224 225 /* 226 * Try to find a child whose DTL doesn't contain the block to read. 227 * If a child is known to be completely inaccessible (indicated by 228 * vdev_readable() returning B_FALSE), don't even try. 229 */ 230 for (i = 0, c = mm->mm_preferred; i < mm->mm_children; i++, c++) { 231 if (c >= mm->mm_children) 232 c = 0; 233 mc = &mm->mm_child[c]; 234 if (mc->mc_tried || mc->mc_skipped) 235 continue; 236 if (!vdev_readable(mc->mc_vd)) { 237 mc->mc_error = SET_ERROR(ENXIO); 238 mc->mc_tried = 1; /* don't even try */ 239 mc->mc_skipped = 1; 240 continue; 241 } 242 if (!vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1)) 243 return (c); 244 mc->mc_error = SET_ERROR(ESTALE); 245 mc->mc_skipped = 1; 246 mc->mc_speculative = 1; 247 } 248 249 /* 250 * Every device is either missing or has this txg in its DTL. 251 * Look for any child we haven't already tried before giving up. 252 */ 253 for (c = 0; c < mm->mm_children; c++) 254 if (!mm->mm_child[c].mc_tried) 255 return (c); 256 257 /* 258 * Every child failed. There's no place left to look. 259 */ 260 return (-1); 261 } 262 263 static void 264 vdev_mirror_io_start(zio_t *zio) 265 { 266 mirror_map_t *mm; 267 mirror_child_t *mc; 268 int c, children; 269 270 mm = vdev_mirror_map_alloc(zio); 271 272 if (zio->io_type == ZIO_TYPE_READ) { 273 if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) { 274 /* 275 * For scrubbing reads we need to allocate a read 276 * buffer for each child and issue reads to all 277 * children. If any child succeeds, it will copy its 278 * data into zio->io_data in vdev_mirror_scrub_done. 279 */ 280 for (c = 0; c < mm->mm_children; c++) { 281 mc = &mm->mm_child[c]; 282 zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 283 mc->mc_vd, mc->mc_offset, 284 zio_buf_alloc(zio->io_size), zio->io_size, 285 zio->io_type, zio->io_priority, 0, 286 vdev_mirror_scrub_done, mc)); 287 } 288 zio_execute(zio); 289 return; 290 } 291 /* 292 * For normal reads just pick one child. 293 */ 294 c = vdev_mirror_child_select(zio); 295 children = (c >= 0); 296 } else { 297 ASSERT(zio->io_type == ZIO_TYPE_WRITE); 298 299 /* 300 * Writes go to all children. 301 */ 302 c = 0; 303 children = mm->mm_children; 304 } 305 306 while (children--) { 307 mc = &mm->mm_child[c]; 308 zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 309 mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size, 310 zio->io_type, zio->io_priority, 0, 311 vdev_mirror_child_done, mc)); 312 c++; 313 } 314 315 zio_execute(zio); 316 } 317 318 static int 319 vdev_mirror_worst_error(mirror_map_t *mm) 320 { 321 int error[2] = { 0, 0 }; 322 323 for (int c = 0; c < mm->mm_children; c++) { 324 mirror_child_t *mc = &mm->mm_child[c]; 325 int s = mc->mc_speculative; 326 error[s] = zio_worst_error(error[s], mc->mc_error); 327 } 328 329 return (error[0] ? error[0] : error[1]); 330 } 331 332 static void 333 vdev_mirror_io_done(zio_t *zio) 334 { 335 mirror_map_t *mm = zio->io_vsd; 336 mirror_child_t *mc; 337 int c; 338 int good_copies = 0; 339 int unexpected_errors = 0; 340 341 for (c = 0; c < mm->mm_children; c++) { 342 mc = &mm->mm_child[c]; 343 344 if (mc->mc_error) { 345 if (!mc->mc_skipped) 346 unexpected_errors++; 347 } else if (mc->mc_tried) { 348 good_copies++; 349 } 350 } 351 352 if (zio->io_type == ZIO_TYPE_WRITE) { 353 /* 354 * XXX -- for now, treat partial writes as success. 355 * 356 * Now that we support write reallocation, it would be better 357 * to treat partial failure as real failure unless there are 358 * no non-degraded top-level vdevs left, and not update DTLs 359 * if we intend to reallocate. 360 */ 361 /* XXPOLICY */ 362 if (good_copies != mm->mm_children) { 363 /* 364 * Always require at least one good copy. 365 * 366 * For ditto blocks (io_vd == NULL), require 367 * all copies to be good. 368 * 369 * XXX -- for replacing vdevs, there's no great answer. 370 * If the old device is really dead, we may not even 371 * be able to access it -- so we only want to 372 * require good writes to the new device. But if 373 * the new device turns out to be flaky, we want 374 * to be able to detach it -- which requires all 375 * writes to the old device to have succeeded. 376 */ 377 if (good_copies == 0 || zio->io_vd == NULL) 378 zio->io_error = vdev_mirror_worst_error(mm); 379 } 380 return; 381 } 382 383 ASSERT(zio->io_type == ZIO_TYPE_READ); 384 385 /* 386 * If we don't have a good copy yet, keep trying other children. 387 */ 388 /* XXPOLICY */ 389 if (good_copies == 0 && (c = vdev_mirror_child_select(zio)) != -1) { 390 ASSERT(c >= 0 && c < mm->mm_children); 391 mc = &mm->mm_child[c]; 392 zio_vdev_io_redone(zio); 393 zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 394 mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size, 395 ZIO_TYPE_READ, zio->io_priority, 0, 396 vdev_mirror_child_done, mc)); 397 return; 398 } 399 400 /* XXPOLICY */ 401 if (good_copies == 0) { 402 zio->io_error = vdev_mirror_worst_error(mm); 403 ASSERT(zio->io_error != 0); 404 } 405 406 if (good_copies && spa_writeable(zio->io_spa) && 407 (unexpected_errors || 408 (zio->io_flags & ZIO_FLAG_RESILVER) || 409 ((zio->io_flags & ZIO_FLAG_SCRUB) && mm->mm_replacing))) { 410 /* 411 * Use the good data we have in hand to repair damaged children. 412 */ 413 for (c = 0; c < mm->mm_children; c++) { 414 /* 415 * Don't rewrite known good children. 416 * Not only is it unnecessary, it could 417 * actually be harmful: if the system lost 418 * power while rewriting the only good copy, 419 * there would be no good copies left! 420 */ 421 mc = &mm->mm_child[c]; 422 423 if (mc->mc_error == 0) { 424 if (mc->mc_tried) 425 continue; 426 if (!(zio->io_flags & ZIO_FLAG_SCRUB) && 427 !vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL, 428 zio->io_txg, 1)) 429 continue; 430 mc->mc_error = SET_ERROR(ESTALE); 431 } 432 433 zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 434 mc->mc_vd, mc->mc_offset, 435 zio->io_data, zio->io_size, 436 ZIO_TYPE_WRITE, ZIO_PRIORITY_ASYNC_WRITE, 437 ZIO_FLAG_IO_REPAIR | (unexpected_errors ? 438 ZIO_FLAG_SELF_HEAL : 0), NULL, NULL)); 439 } 440 } 441 } 442 443 static void 444 vdev_mirror_state_change(vdev_t *vd, int faulted, int degraded) 445 { 446 if (faulted == vd->vdev_children) 447 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN, 448 VDEV_AUX_NO_REPLICAS); 449 else if (degraded + faulted != 0) 450 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE); 451 else 452 vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE); 453 } 454 455 vdev_ops_t vdev_mirror_ops = { 456 vdev_mirror_open, 457 vdev_mirror_close, 458 vdev_default_asize, 459 vdev_mirror_io_start, 460 vdev_mirror_io_done, 461 vdev_mirror_state_change, 462 NULL, 463 NULL, 464 VDEV_TYPE_MIRROR, /* name of this vdev type */ 465 B_FALSE /* not a leaf vdev */ 466 }; 467 468 vdev_ops_t vdev_replacing_ops = { 469 vdev_mirror_open, 470 vdev_mirror_close, 471 vdev_default_asize, 472 vdev_mirror_io_start, 473 vdev_mirror_io_done, 474 vdev_mirror_state_change, 475 NULL, 476 NULL, 477 VDEV_TYPE_REPLACING, /* name of this vdev type */ 478 B_FALSE /* not a leaf vdev */ 479 }; 480 481 vdev_ops_t vdev_spare_ops = { 482 vdev_mirror_open, 483 vdev_mirror_close, 484 vdev_default_asize, 485 vdev_mirror_io_start, 486 vdev_mirror_io_done, 487 vdev_mirror_state_change, 488 NULL, 489 NULL, 490 VDEV_TYPE_SPARE, /* name of this vdev type */ 491 B_FALSE /* not a leaf vdev */ 492 }; 493