vdev_mirror.c revision 277760
1224524Smm/* 2224524Smm * CDDL HEADER START 3224524Smm * 4224524Smm * The contents of this file are subject to the terms of the 5224524Smm * Common Development and Distribution License (the "License"). 6224524Smm * You may not use this file except in compliance with the License. 7220150Smm * 8220150Smm * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9220150Smm * or http://www.opensolaris.org/os/licensing. 10220150Smm * See the License for the specific language governing permissions 11220150Smm * and limitations under the License. 12220150Smm * 13220150Smm * When distributing Covered Code, include this CDDL HEADER in each 14220150Smm * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15220150Smm * If applicable, add the following below this CDDL HEADER, with the 16220150Smm * fields enclosed by brackets "[]" replaced with your own identifying 17220150Smm * information: Portions Copyright [yyyy] [name of copyright owner] 18220150Smm * 19220150Smm * CDDL HEADER END 20220150Smm */ 21220150Smm/* 22220150Smm * Copyright 2010 Sun Microsystems, Inc. All rights reserved. 23220150Smm * Use is subject to license terms. 24220150Smm */ 25220150Smm 26220150Smm/* 27220150Smm * Copyright (c) 2013 by Delphix. All rights reserved. 28220150Smm */ 29220150Smm 30220150Smm#include <sys/zfs_context.h> 31220150Smm#include <sys/spa.h> 32220150Smm#include <sys/vdev_impl.h> 33220150Smm#include <sys/zio.h> 34220150Smm#include <sys/fs/zfs.h> 35220150Smm 36220150Smm/* 37220150Smm * Virtual device vector for mirroring. 38220150Smm */ 39220150Smm 40220150Smmtypedef struct mirror_child { 41220150Smm vdev_t *mc_vd; 42220150Smm uint64_t mc_offset; 43220150Smm int mc_error; 44220150Smm int mc_load; 45220150Smm uint8_t mc_tried; 46220150Smm uint8_t mc_skipped; 47220150Smm uint8_t mc_speculative; 48220150Smm} mirror_child_t; 49220150Smm 50220150Smmtypedef struct mirror_map { 51220150Smm int *mm_preferred; 52220150Smm int mm_preferred_cnt; 53220150Smm int mm_children; 54220150Smm boolean_t mm_replacing; 55220150Smm boolean_t mm_root; 56220150Smm mirror_child_t mm_child[]; 57220150Smm} mirror_map_t; 58220150Smm 59220150Smmstatic int vdev_mirror_shift = 21; 60220150Smm 61220150SmmSYSCTL_DECL(_vfs_zfs_vdev); 62220150Smmstatic SYSCTL_NODE(_vfs_zfs_vdev, OID_AUTO, mirror, CTLFLAG_RD, 0, 63220150Smm "ZFS VDEV Mirror"); 64220150Smm 65220150Smm/* 66220150Smm * The load configuration settings below are tuned by default for 67220150Smm * the case where all devices are of the same rotational type. 68220150Smm * 69220150Smm * If there is a mixture of rotating and non-rotating media, setting 70171825Skan * non_rotating_seek_inc to 0 may well provide better results as it 71171825Skan * will direct more reads to the non-rotating vdevs which are more 72171825Skan * likely to have a higher performance. 73171825Skan */ 74171825Skan 75171825Skan/* Rotating media load calculation configuration. */ 76171825Skanstatic int rotating_inc = 0; 77171825SkanTUNABLE_INT("vfs.zfs.vdev.mirror.rotating_inc", &rotating_inc); 78171825SkanSYSCTL_INT(_vfs_zfs_vdev_mirror, OID_AUTO, rotating_inc, CTLFLAG_RW, 79171825Skan &rotating_inc, 0, "Rotating media load increment for non-seeking I/O's"); 80171825Skan 81171825Skanstatic int rotating_seek_inc = 5; 82171825SkanTUNABLE_INT("vfs.zfs.vdev.mirror.rotating_seek_inc", &rotating_seek_inc); 83171825SkanSYSCTL_INT(_vfs_zfs_vdev_mirror, OID_AUTO, rotating_seek_inc, CTLFLAG_RW, 84171825Skan &rotating_seek_inc, 0, "Rotating media load increment for seeking I/O's"); 85171825Skan 86171825Skanstatic int rotating_seek_offset = 1 * 1024 * 1024; 87171825SkanTUNABLE_INT("vfs.zfs.vdev.mirror.rotating_seek_offset", &rotating_seek_offset); 88171825SkanSYSCTL_INT(_vfs_zfs_vdev_mirror, OID_AUTO, rotating_seek_offset, CTLFLAG_RW, 89171825Skan &rotating_seek_offset, 0, "Offset in bytes from the last I/O which " 90171825Skan "triggers a reduced rotating media seek increment"); 91171825Skan 92171825Skan/* Non-rotating media load calculation configuration. */ 93171825Skanstatic int non_rotating_inc = 0; 94171825SkanTUNABLE_INT("vfs.zfs.vdev.mirror.non_rotating_inc", &non_rotating_inc); 95171825SkanSYSCTL_INT(_vfs_zfs_vdev_mirror, OID_AUTO, non_rotating_inc, CTLFLAG_RW, 96171825Skan &non_rotating_inc, 0, 97171825Skan "Non-rotating media load increment for non-seeking I/O's"); 98171825Skan 99171825Skanstatic int non_rotating_seek_inc = 1; 100171825SkanTUNABLE_INT("vfs.zfs.vdev.mirror.non_rotating_seek_inc", 101171825Skan &non_rotating_seek_inc); 102171825SkanSYSCTL_INT(_vfs_zfs_vdev_mirror, OID_AUTO, non_rotating_seek_inc, CTLFLAG_RW, 103171825Skan &non_rotating_seek_inc, 0, 104171825Skan "Non-rotating media load increment for seeking I/O's"); 105171825Skan 106171825Skan 107171825Skanstatic inline size_t 108171825Skanvdev_mirror_map_size(int children) 109171825Skan{ 110171825Skan return (offsetof(mirror_map_t, mm_child[children]) + 111171825Skan sizeof(int) * children); 112171825Skan} 113171825Skan 114171825Skanstatic inline mirror_map_t * 115171825Skanvdev_mirror_map_alloc(int children, boolean_t replacing, boolean_t root) 116171825Skan{ 117171825Skan mirror_map_t *mm; 118171825Skan 119171825Skan mm = kmem_zalloc(vdev_mirror_map_size(children), KM_SLEEP); 120171825Skan mm->mm_children = children; 121171825Skan mm->mm_replacing = replacing; 122171825Skan mm->mm_root = root; 123171825Skan mm->mm_preferred = (int *)((uintptr_t)mm + 124171825Skan offsetof(mirror_map_t, mm_child[children])); 125171825Skan 126171825Skan return mm; 127171825Skan} 128171825Skan 129171825Skanstatic void 130171825Skanvdev_mirror_map_free(zio_t *zio) 131171825Skan{ 132171825Skan mirror_map_t *mm = zio->io_vsd; 133171825Skan 134171825Skan kmem_free(mm, vdev_mirror_map_size(mm->mm_children)); 135171825Skan} 136171825Skan 137171825Skanstatic const zio_vsd_ops_t vdev_mirror_vsd_ops = { 138171825Skan vdev_mirror_map_free, 139171825Skan zio_vsd_default_cksum_report 140171825Skan}; 141171825Skan 142171825Skanstatic int 143171825Skanvdev_mirror_load(mirror_map_t *mm, vdev_t *vd, uint64_t zio_offset) 144171825Skan{ 145171825Skan uint64_t lastoffset; 146171825Skan int load; 147171825Skan 148171825Skan /* All DVAs have equal weight at the root. */ 149171825Skan if (mm->mm_root) 150171825Skan return (INT_MAX); 151171825Skan 152171825Skan /* 153171825Skan * We don't return INT_MAX if the device is resilvering i.e. 154171825Skan * vdev_resilver_txg != 0 as when tested performance was slightly 155171825Skan * worse overall when resilvering with compared to without. 156171825Skan */ 157171825Skan 158171825Skan /* Standard load based on pending queue length. */ 159171825Skan load = vdev_queue_length(vd); 160169689Skan lastoffset = vdev_queue_lastoffset(vd); 161161651Skan 162169689Skan if (vd->vdev_rotation_rate == VDEV_RATE_NON_ROTATING) { 163161651Skan /* Non-rotating media. */ 164169689Skan if (lastoffset == zio_offset) 165161651Skan return (load + non_rotating_inc); 166169689Skan 167169689Skan /* 168169689Skan * Apply a seek penalty even for non-rotating devices as 169169689Skan * sequential I/O'a can be aggregated into fewer operations 170169689Skan * on the device, thus avoiding unnecessary per-command 171169689Skan * overhead and boosting performance. 172169689Skan */ 173169689Skan return (load + non_rotating_seek_inc); 174169689Skan } 175169689Skan 176169689Skan /* Rotating media I/O's which directly follow the last I/O. */ 177169689Skan if (lastoffset == zio_offset) 178169689Skan return (load + rotating_inc); 179169689Skan 180169689Skan /* 181169689Skan * Apply half the seek increment to I/O's within seek offset 182169689Skan * of the last I/O queued to this vdev as they should incure less 183169689Skan * of a seek increment. 184169689Skan */ 185169689Skan if (ABS(lastoffset - zio_offset) < rotating_seek_offset) 186169689Skan return (load + (rotating_seek_inc / 2)); 187169689Skan 188169689Skan /* Apply the full seek increment to all other I/O's. */ 189169689Skan return (load + rotating_seek_inc); 190169689Skan} 191169689Skan 192169689Skan 193169689Skanstatic mirror_map_t * 194169689Skanvdev_mirror_map_init(zio_t *zio) 195169689Skan{ 196169689Skan mirror_map_t *mm = NULL; 197169689Skan mirror_child_t *mc; 198169689Skan vdev_t *vd = zio->io_vd; 199169689Skan int c; 200169689Skan 201169689Skan if (vd == NULL) { 202169689Skan dva_t *dva = zio->io_bp->blk_dva; 203169689Skan spa_t *spa = zio->io_spa; 204169689Skan 205169689Skan mm = vdev_mirror_map_alloc(BP_GET_NDVAS(zio->io_bp), B_FALSE, 206169689Skan B_TRUE); 207169689Skan for (c = 0; c < mm->mm_children; c++) { 208169689Skan mc = &mm->mm_child[c]; 209169689Skan mc->mc_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[c])); 210169689Skan mc->mc_offset = DVA_GET_OFFSET(&dva[c]); 211169689Skan } 212169689Skan } else { 213169689Skan mm = vdev_mirror_map_alloc(vd->vdev_children, 214169689Skan (vd->vdev_ops == &vdev_replacing_ops || 215169689Skan vd->vdev_ops == &vdev_spare_ops), B_FALSE); 216169689Skan for (c = 0; c < mm->mm_children; c++) { 217169689Skan mc = &mm->mm_child[c]; 218169689Skan mc->mc_vd = vd->vdev_child[c]; 219169689Skan mc->mc_offset = zio->io_offset; 220169689Skan } 221169689Skan } 222169689Skan 223169689Skan zio->io_vsd = mm; 224169689Skan zio->io_vsd_ops = &vdev_mirror_vsd_ops; 225169689Skan return (mm); 226169689Skan} 227169689Skan 228169689Skanstatic int 229169689Skanvdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize, 230169689Skan uint64_t *logical_ashift, uint64_t *physical_ashift) 231169689Skan{ 232169689Skan int numerrors = 0; 233169689Skan int lasterror = 0; 234169689Skan 235169689Skan if (vd->vdev_children == 0) { 236169689Skan vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL; 237169689Skan return (SET_ERROR(EINVAL)); 238169689Skan } 239169689Skan 240169689Skan vdev_open_children(vd); 241169689Skan 242169689Skan for (int c = 0; c < vd->vdev_children; c++) { 243169689Skan vdev_t *cvd = vd->vdev_child[c]; 244169689Skan 245169689Skan if (cvd->vdev_open_error) { 246169689Skan lasterror = cvd->vdev_open_error; 247169689Skan numerrors++; 248169689Skan continue; 249169689Skan } 250169689Skan 251169689Skan *asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1; 252169689Skan *max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1; 253169689Skan *logical_ashift = MAX(*logical_ashift, cvd->vdev_ashift); 254169689Skan *physical_ashift = MAX(*physical_ashift, 255169689Skan cvd->vdev_physical_ashift); 256169689Skan } 257169689Skan 258169689Skan if (numerrors == vd->vdev_children) { 259169689Skan vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS; 260169689Skan return (lasterror); 261169689Skan } 262169689Skan 263169689Skan return (0); 264169689Skan} 265169689Skan 266169689Skanstatic void 267169689Skanvdev_mirror_close(vdev_t *vd) 268169689Skan{ 269169689Skan for (int c = 0; c < vd->vdev_children; c++) 270169689Skan vdev_close(vd->vdev_child[c]); 271169689Skan} 272169689Skan 273169689Skanstatic void 274169689Skanvdev_mirror_child_done(zio_t *zio) 275169689Skan{ 276169689Skan mirror_child_t *mc = zio->io_private; 277169689Skan 278169689Skan mc->mc_error = zio->io_error; 279169689Skan mc->mc_tried = 1; 280169689Skan mc->mc_skipped = 0; 281169689Skan} 282169689Skan 283169689Skanstatic void 284169689Skanvdev_mirror_scrub_done(zio_t *zio) 285169689Skan{ 286169689Skan mirror_child_t *mc = zio->io_private; 287169689Skan 288169689Skan if (zio->io_error == 0) { 289169689Skan zio_t *pio; 290169689Skan 291169689Skan mutex_enter(&zio->io_lock); 292169689Skan while ((pio = zio_walk_parents(zio)) != NULL) { 293169689Skan mutex_enter(&pio->io_lock); 294169689Skan ASSERT3U(zio->io_size, >=, pio->io_size); 295169689Skan bcopy(zio->io_data, pio->io_data, pio->io_size); 296169689Skan mutex_exit(&pio->io_lock); 297169689Skan } 298169689Skan mutex_exit(&zio->io_lock); 299169689Skan } 300169689Skan 301169689Skan zio_buf_free(zio->io_data, zio->io_size); 302169689Skan 303169689Skan mc->mc_error = zio->io_error; 304169689Skan mc->mc_tried = 1; 305169689Skan mc->mc_skipped = 0; 306169689Skan} 307169689Skan 308169689Skan/* 309169689Skan * Check the other, lower-index DVAs to see if they're on the same 310169689Skan * vdev as the child we picked. If they are, use them since they 311169689Skan * are likely to have been allocated from the primary metaslab in 312169689Skan * use at the time, and hence are more likely to have locality with 313169689Skan * single-copy data. 314169689Skan */ 315169689Skanstatic int 316169689Skanvdev_mirror_dva_select(zio_t *zio, int p) 317169689Skan{ 318169689Skan dva_t *dva = zio->io_bp->blk_dva; 319169689Skan mirror_map_t *mm = zio->io_vsd; 320169689Skan int preferred; 321169689Skan int c; 322169689Skan 323169689Skan preferred = mm->mm_preferred[p]; 324169689Skan for (p-- ; p >= 0; p--) { 325169689Skan c = mm->mm_preferred[p]; 326169689Skan if (DVA_GET_VDEV(&dva[c]) == DVA_GET_VDEV(&dva[preferred])) 327169689Skan preferred = c; 328169689Skan } 329169689Skan return (preferred); 330169689Skan} 331169689Skan 332169689Skanstatic int 333169689Skanvdev_mirror_preferred_child_randomize(zio_t *zio) 334169689Skan{ 335169689Skan mirror_map_t *mm = zio->io_vsd; 336169689Skan int p; 337169689Skan 338169689Skan if (mm->mm_root) { 339169689Skan p = spa_get_random(mm->mm_preferred_cnt); 340169689Skan return (vdev_mirror_dva_select(zio, p)); 341169689Skan } 342169689Skan 343169689Skan /* 344169689Skan * To ensure we don't always favour the first matching vdev, 345169689Skan * which could lead to wear leveling issues on SSD's, we 346169689Skan * use the I/O offset as a pseudo random seed into the vdevs 347169689Skan * which have the lowest load. 348169689Skan */ 349169689Skan p = (zio->io_offset >> vdev_mirror_shift) % mm->mm_preferred_cnt; 350169689Skan return (mm->mm_preferred[p]); 351169689Skan} 352169689Skan 353169689Skan/* 354169689Skan * Try to find a vdev whose DTL doesn't contain the block we want to read 355169689Skan * prefering vdevs based on determined load. 356169689Skan * 357169689Skan * If we can't, try the read on any vdev we haven't already tried. 358169689Skan */ 359169689Skanstatic int 360169689Skanvdev_mirror_child_select(zio_t *zio) 361169689Skan{ 362169689Skan mirror_map_t *mm = zio->io_vsd; 363169689Skan uint64_t txg = zio->io_txg; 364169689Skan int c, lowest_load; 365169689Skan 366169689Skan ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg); 367169689Skan 368169689Skan lowest_load = INT_MAX; 369169689Skan mm->mm_preferred_cnt = 0; 370169689Skan for (c = 0; c < mm->mm_children; c++) { 371169689Skan mirror_child_t *mc; 372169689Skan 373169689Skan mc = &mm->mm_child[c]; 374169689Skan if (mc->mc_tried || mc->mc_skipped) 375169689Skan continue; 376169689Skan 377169689Skan if (!vdev_readable(mc->mc_vd)) { 378169689Skan mc->mc_error = SET_ERROR(ENXIO); 379169689Skan mc->mc_tried = 1; /* don't even try */ 380169689Skan mc->mc_skipped = 1; 381169689Skan continue; 382169689Skan } 383169689Skan 384169689Skan if (vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1)) { 385169689Skan mc->mc_error = SET_ERROR(ESTALE); 386169689Skan mc->mc_skipped = 1; 387169689Skan mc->mc_speculative = 1; 388169689Skan continue; 389169689Skan } 390169689Skan 391169689Skan mc->mc_load = vdev_mirror_load(mm, mc->mc_vd, mc->mc_offset); 392169689Skan if (mc->mc_load > lowest_load) 393169689Skan continue; 394169689Skan 395169689Skan if (mc->mc_load < lowest_load) { 396169689Skan lowest_load = mc->mc_load; 397169689Skan mm->mm_preferred_cnt = 0; 398169689Skan } 399169689Skan mm->mm_preferred[mm->mm_preferred_cnt] = c; 400169689Skan mm->mm_preferred_cnt++; 401169689Skan } 402169689Skan 403169689Skan if (mm->mm_preferred_cnt == 1) { 404169689Skan vdev_queue_register_lastoffset( 405169689Skan mm->mm_child[mm->mm_preferred[0]].mc_vd, zio); 406169689Skan return (mm->mm_preferred[0]); 407169689Skan } 408169689Skan 409169689Skan if (mm->mm_preferred_cnt > 1) { 410169689Skan int c = vdev_mirror_preferred_child_randomize(zio); 411169689Skan 412169689Skan vdev_queue_register_lastoffset(mm->mm_child[c].mc_vd, zio); 413169689Skan return (c); 414169689Skan } 415169689Skan 416169689Skan /* 417169689Skan * Every device is either missing or has this txg in its DTL. 418169689Skan * Look for any child we haven't already tried before giving up. 419169689Skan */ 420169689Skan for (c = 0; c < mm->mm_children; c++) { 421169689Skan if (!mm->mm_child[c].mc_tried) { 422169689Skan vdev_queue_register_lastoffset(mm->mm_child[c].mc_vd, 423169689Skan zio); 424169689Skan return (c); 425169689Skan } 426169689Skan } 427169689Skan 428169689Skan /* 429169689Skan * Every child failed. There's no place left to look. 430169689Skan */ 431169689Skan return (-1); 432169689Skan} 433169689Skan 434169689Skanstatic int 435169689Skanvdev_mirror_io_start(zio_t *zio) 436169689Skan{ 437169689Skan mirror_map_t *mm; 438169689Skan mirror_child_t *mc; 439169689Skan int c, children; 440169689Skan 441169689Skan mm = vdev_mirror_map_init(zio); 442169689Skan 443169689Skan if (zio->io_type == ZIO_TYPE_READ) { 444169689Skan if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing && 445169689Skan mm->mm_children > 1) { 446169689Skan /* 447169689Skan * For scrubbing reads we need to allocate a read 448169689Skan * buffer for each child and issue reads to all 449169689Skan * children. If any child succeeds, it will copy its 450169689Skan * data into zio->io_data in vdev_mirror_scrub_done. 451169689Skan */ 452169689Skan for (c = 0; c < mm->mm_children; c++) { 453169689Skan mc = &mm->mm_child[c]; 454169689Skan zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 455169689Skan mc->mc_vd, mc->mc_offset, 456169689Skan zio_buf_alloc(zio->io_size), zio->io_size, 457169689Skan zio->io_type, zio->io_priority, 0, 458169689Skan vdev_mirror_scrub_done, mc)); 459169689Skan } 460169689Skan zio_interrupt(zio); 461169689Skan return (ZIO_PIPELINE_STOP); 462169689Skan } 463169689Skan /* 464169689Skan * For normal reads just pick one child. 465169689Skan */ 466169689Skan c = vdev_mirror_child_select(zio); 467169689Skan children = (c >= 0); 468169689Skan } else { 469169689Skan ASSERT(zio->io_type == ZIO_TYPE_WRITE || 470169689Skan zio->io_type == ZIO_TYPE_FREE); 471169689Skan 472169689Skan /* 473169689Skan * Writes and frees go to all children. 474169689Skan */ 475169689Skan c = 0; 476169689Skan children = mm->mm_children; 477169689Skan } 478169689Skan 479169689Skan while (children--) { 480169689Skan mc = &mm->mm_child[c]; 481169689Skan zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 482169689Skan mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size, 483169689Skan zio->io_type, zio->io_priority, 0, 484169689Skan vdev_mirror_child_done, mc)); 485169689Skan c++; 486169689Skan } 487169689Skan 488169689Skan zio_interrupt(zio); 489169689Skan return (ZIO_PIPELINE_STOP); 490169689Skan} 491169689Skan 492169689Skanstatic int 493169689Skanvdev_mirror_worst_error(mirror_map_t *mm) 494169689Skan{ 495169689Skan int error[2] = { 0, 0 }; 496169689Skan 497169689Skan for (int c = 0; c < mm->mm_children; c++) { 498169689Skan mirror_child_t *mc = &mm->mm_child[c]; 499169689Skan int s = mc->mc_speculative; 500169689Skan error[s] = zio_worst_error(error[s], mc->mc_error); 501169689Skan } 502169689Skan 503169689Skan return (error[0] ? error[0] : error[1]); 504169689Skan} 505169689Skan 506169689Skanstatic void 507169689Skanvdev_mirror_io_done(zio_t *zio) 508169689Skan{ 509169689Skan mirror_map_t *mm = zio->io_vsd; 510169689Skan mirror_child_t *mc; 511169689Skan int c; 512169689Skan int good_copies = 0; 513169689Skan int unexpected_errors = 0; 514169689Skan 515169689Skan for (c = 0; c < mm->mm_children; c++) { 516169689Skan mc = &mm->mm_child[c]; 517169689Skan 518169689Skan if (mc->mc_error) { 519169689Skan if (!mc->mc_skipped) 520169689Skan unexpected_errors++; 521169689Skan } else if (mc->mc_tried) { 522169689Skan good_copies++; 523169689Skan } 524169689Skan } 525169689Skan 526169689Skan if (zio->io_type == ZIO_TYPE_WRITE) { 527169689Skan /* 528169689Skan * XXX -- for now, treat partial writes as success. 529169689Skan * 530169689Skan * Now that we support write reallocation, it would be better 531169689Skan * to treat partial failure as real failure unless there are 532169689Skan * no non-degraded top-level vdevs left, and not update DTLs 533169689Skan * if we intend to reallocate. 534169689Skan */ 535169689Skan /* XXPOLICY */ 536169689Skan if (good_copies != mm->mm_children) { 537169689Skan /* 538169689Skan * Always require at least one good copy. 539169689Skan * 540169689Skan * For ditto blocks (io_vd == NULL), require 541169689Skan * all copies to be good. 542169689Skan * 543169689Skan * XXX -- for replacing vdevs, there's no great answer. 544169689Skan * If the old device is really dead, we may not even 545169689Skan * be able to access it -- so we only want to 546169689Skan * require good writes to the new device. But if 547169689Skan * the new device turns out to be flaky, we want 548169689Skan * to be able to detach it -- which requires all 549169689Skan * writes to the old device to have succeeded. 550169689Skan */ 551169689Skan if (good_copies == 0 || zio->io_vd == NULL) 552169689Skan zio->io_error = vdev_mirror_worst_error(mm); 553169689Skan } 554169689Skan return; 555169689Skan } else if (zio->io_type == ZIO_TYPE_FREE) { 556169689Skan return; 557169689Skan } 558169689Skan 559169689Skan ASSERT(zio->io_type == ZIO_TYPE_READ); 560169689Skan 561169689Skan /* 562169689Skan * If we don't have a good copy yet, keep trying other children. 563169689Skan */ 564169689Skan /* XXPOLICY */ 565169689Skan if (good_copies == 0 && (c = vdev_mirror_child_select(zio)) != -1) { 566169689Skan ASSERT(c >= 0 && c < mm->mm_children); 567169689Skan mc = &mm->mm_child[c]; 568169689Skan zio_vdev_io_redone(zio); 569169689Skan zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 570169689Skan mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size, 571169689Skan ZIO_TYPE_READ, zio->io_priority, 0, 572169689Skan vdev_mirror_child_done, mc)); 573169689Skan return; 574169689Skan } 575169689Skan 576169689Skan /* XXPOLICY */ 577169689Skan if (good_copies == 0) { 578169689Skan zio->io_error = vdev_mirror_worst_error(mm); 579169689Skan ASSERT(zio->io_error != 0); 580169689Skan } 581169689Skan 582169689Skan if (good_copies && spa_writeable(zio->io_spa) && 583169689Skan (unexpected_errors || 584169689Skan (zio->io_flags & ZIO_FLAG_RESILVER) || 585169689Skan ((zio->io_flags & ZIO_FLAG_SCRUB) && mm->mm_replacing))) { 586169689Skan /* 587169689Skan * Use the good data we have in hand to repair damaged children. 588169689Skan */ 589169689Skan for (c = 0; c < mm->mm_children; c++) { 590169689Skan /* 591169689Skan * Don't rewrite known good children. 592169689Skan * Not only is it unnecessary, it could 593169689Skan * actually be harmful: if the system lost 594169689Skan * power while rewriting the only good copy, 595169689Skan * there would be no good copies left! 596169689Skan */ 597169689Skan mc = &mm->mm_child[c]; 598169689Skan 599169689Skan if (mc->mc_error == 0) { 600169689Skan if (mc->mc_tried) 601169689Skan continue; 602169689Skan if (!(zio->io_flags & ZIO_FLAG_SCRUB) && 603169689Skan !vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL, 604169689Skan zio->io_txg, 1)) 605169689Skan continue; 606169689Skan mc->mc_error = SET_ERROR(ESTALE); 607169689Skan } 608169689Skan 609169689Skan zio_nowait(zio_vdev_child_io(zio, zio->io_bp, 610169689Skan mc->mc_vd, mc->mc_offset, 611169689Skan zio->io_data, zio->io_size, 612169689Skan ZIO_TYPE_WRITE, ZIO_PRIORITY_ASYNC_WRITE, 613169689Skan ZIO_FLAG_IO_REPAIR | (unexpected_errors ? 614169689Skan ZIO_FLAG_SELF_HEAL : 0), NULL, NULL)); 615169689Skan } 616169689Skan } 617169689Skan} 618169689Skan 619169689Skanstatic void 620169689Skanvdev_mirror_state_change(vdev_t *vd, int faulted, int degraded) 621169689Skan{ 622169689Skan if (faulted == vd->vdev_children) 623169689Skan vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN, 624169689Skan VDEV_AUX_NO_REPLICAS); 625169689Skan else if (degraded + faulted != 0) 626169689Skan vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE); 627169689Skan else 628169689Skan vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE); 629169689Skan} 630169689Skan 631169689Skanvdev_ops_t vdev_mirror_ops = { 632169689Skan vdev_mirror_open, 633169689Skan vdev_mirror_close, 634169689Skan vdev_default_asize, 635169689Skan vdev_mirror_io_start, 636169689Skan vdev_mirror_io_done, 637169689Skan vdev_mirror_state_change, 638169689Skan NULL, 639169689Skan NULL, 640169689Skan VDEV_TYPE_MIRROR, /* name of this vdev type */ 641169689Skan B_FALSE /* not a leaf vdev */ 642169689Skan}; 643169689Skan 644169689Skanvdev_ops_t vdev_replacing_ops = { 645169689Skan vdev_mirror_open, 646169689Skan vdev_mirror_close, 647169689Skan vdev_default_asize, 648169689Skan vdev_mirror_io_start, 649169689Skan vdev_mirror_io_done, 650169689Skan vdev_mirror_state_change, 651169689Skan NULL, 652169689Skan NULL, 653169689Skan VDEV_TYPE_REPLACING, /* name of this vdev type */ 654169689Skan B_FALSE /* not a leaf vdev */ 655169689Skan}; 656169689Skan 657169689Skanvdev_ops_t vdev_spare_ops = { 658169689Skan vdev_mirror_open, 659169689Skan vdev_mirror_close, 660169689Skan vdev_default_asize, 661169689Skan vdev_mirror_io_start, 662169689Skan vdev_mirror_io_done, 663169689Skan vdev_mirror_state_change, 664169689Skan NULL, 665169689Skan NULL, 666169689Skan VDEV_TYPE_SPARE, /* name of this vdev type */ 667169689Skan B_FALSE /* not a leaf vdev */ 668169689Skan}; 669169689Skan