Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * raid10.c : Multiple Devices driver for Linux |
| 3 | * |
| 4 | * Copyright (C) 2000-2004 Neil Brown |
| 5 | * |
| 6 | * RAID-10 support for md. |
| 7 | * |
| 8 | * Base on code in raid1.c. See raid1.c for futher copyright information. |
| 9 | * |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License as published by |
| 13 | * the Free Software Foundation; either version 2, or (at your option) |
| 14 | * any later version. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * (for example /usr/src/linux/COPYING); if not, write to the Free |
| 18 | * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 19 | */ |
| 20 | |
| 21 | #include <linux/raid/raid10.h> |
| 22 | |
| 23 | /* |
| 24 | * RAID10 provides a combination of RAID0 and RAID1 functionality. |
| 25 | * The layout of data is defined by |
| 26 | * chunk_size |
| 27 | * raid_disks |
| 28 | * near_copies (stored in low byte of layout) |
| 29 | * far_copies (stored in second byte of layout) |
| 30 | * |
| 31 | * The data to be stored is divided into chunks using chunksize. |
| 32 | * Each device is divided into far_copies sections. |
| 33 | * In each section, chunks are laid out in a style similar to raid0, but |
| 34 | * near_copies copies of each chunk is stored (each on a different drive). |
| 35 | * The starting device for each section is offset near_copies from the starting |
| 36 | * device of the previous section. |
| 37 | * Thus there are (near_copies*far_copies) of each chunk, and each is on a different |
| 38 | * drive. |
| 39 | * near_copies and far_copies must be at least one, and their product is at most |
| 40 | * raid_disks. |
| 41 | */ |
| 42 | |
| 43 | /* |
| 44 | * Number of guaranteed r10bios in case of extreme VM load: |
| 45 | */ |
| 46 | #define NR_RAID10_BIOS 256 |
| 47 | |
| 48 | static void unplug_slaves(mddev_t *mddev); |
| 49 | |
| 50 | static void * r10bio_pool_alloc(unsigned int __nocast gfp_flags, void *data) |
| 51 | { |
| 52 | conf_t *conf = data; |
| 53 | r10bio_t *r10_bio; |
| 54 | int size = offsetof(struct r10bio_s, devs[conf->copies]); |
| 55 | |
| 56 | /* allocate a r10bio with room for raid_disks entries in the bios array */ |
| 57 | r10_bio = kmalloc(size, gfp_flags); |
| 58 | if (r10_bio) |
| 59 | memset(r10_bio, 0, size); |
| 60 | else |
| 61 | unplug_slaves(conf->mddev); |
| 62 | |
| 63 | return r10_bio; |
| 64 | } |
| 65 | |
| 66 | static void r10bio_pool_free(void *r10_bio, void *data) |
| 67 | { |
| 68 | kfree(r10_bio); |
| 69 | } |
| 70 | |
| 71 | #define RESYNC_BLOCK_SIZE (64*1024) |
| 72 | //#define RESYNC_BLOCK_SIZE PAGE_SIZE |
| 73 | #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) |
| 74 | #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) |
| 75 | #define RESYNC_WINDOW (2048*1024) |
| 76 | |
| 77 | /* |
| 78 | * When performing a resync, we need to read and compare, so |
| 79 | * we need as many pages are there are copies. |
| 80 | * When performing a recovery, we need 2 bios, one for read, |
| 81 | * one for write (we recover only one drive per r10buf) |
| 82 | * |
| 83 | */ |
| 84 | static void * r10buf_pool_alloc(unsigned int __nocast gfp_flags, void *data) |
| 85 | { |
| 86 | conf_t *conf = data; |
| 87 | struct page *page; |
| 88 | r10bio_t *r10_bio; |
| 89 | struct bio *bio; |
| 90 | int i, j; |
| 91 | int nalloc; |
| 92 | |
| 93 | r10_bio = r10bio_pool_alloc(gfp_flags, conf); |
| 94 | if (!r10_bio) { |
| 95 | unplug_slaves(conf->mddev); |
| 96 | return NULL; |
| 97 | } |
| 98 | |
| 99 | if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) |
| 100 | nalloc = conf->copies; /* resync */ |
| 101 | else |
| 102 | nalloc = 2; /* recovery */ |
| 103 | |
| 104 | /* |
| 105 | * Allocate bios. |
| 106 | */ |
| 107 | for (j = nalloc ; j-- ; ) { |
| 108 | bio = bio_alloc(gfp_flags, RESYNC_PAGES); |
| 109 | if (!bio) |
| 110 | goto out_free_bio; |
| 111 | r10_bio->devs[j].bio = bio; |
| 112 | } |
| 113 | /* |
| 114 | * Allocate RESYNC_PAGES data pages and attach them |
| 115 | * where needed. |
| 116 | */ |
| 117 | for (j = 0 ; j < nalloc; j++) { |
| 118 | bio = r10_bio->devs[j].bio; |
| 119 | for (i = 0; i < RESYNC_PAGES; i++) { |
| 120 | page = alloc_page(gfp_flags); |
| 121 | if (unlikely(!page)) |
| 122 | goto out_free_pages; |
| 123 | |
| 124 | bio->bi_io_vec[i].bv_page = page; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | return r10_bio; |
| 129 | |
| 130 | out_free_pages: |
| 131 | for ( ; i > 0 ; i--) |
| 132 | __free_page(bio->bi_io_vec[i-1].bv_page); |
| 133 | while (j--) |
| 134 | for (i = 0; i < RESYNC_PAGES ; i++) |
| 135 | __free_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page); |
| 136 | j = -1; |
| 137 | out_free_bio: |
| 138 | while ( ++j < nalloc ) |
| 139 | bio_put(r10_bio->devs[j].bio); |
| 140 | r10bio_pool_free(r10_bio, conf); |
| 141 | return NULL; |
| 142 | } |
| 143 | |
| 144 | static void r10buf_pool_free(void *__r10_bio, void *data) |
| 145 | { |
| 146 | int i; |
| 147 | conf_t *conf = data; |
| 148 | r10bio_t *r10bio = __r10_bio; |
| 149 | int j; |
| 150 | |
| 151 | for (j=0; j < conf->copies; j++) { |
| 152 | struct bio *bio = r10bio->devs[j].bio; |
| 153 | if (bio) { |
| 154 | for (i = 0; i < RESYNC_PAGES; i++) { |
| 155 | __free_page(bio->bi_io_vec[i].bv_page); |
| 156 | bio->bi_io_vec[i].bv_page = NULL; |
| 157 | } |
| 158 | bio_put(bio); |
| 159 | } |
| 160 | } |
| 161 | r10bio_pool_free(r10bio, conf); |
| 162 | } |
| 163 | |
| 164 | static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) |
| 165 | { |
| 166 | int i; |
| 167 | |
| 168 | for (i = 0; i < conf->copies; i++) { |
| 169 | struct bio **bio = & r10_bio->devs[i].bio; |
| 170 | if (*bio) |
| 171 | bio_put(*bio); |
| 172 | *bio = NULL; |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | static inline void free_r10bio(r10bio_t *r10_bio) |
| 177 | { |
| 178 | unsigned long flags; |
| 179 | |
| 180 | conf_t *conf = mddev_to_conf(r10_bio->mddev); |
| 181 | |
| 182 | /* |
| 183 | * Wake up any possible resync thread that waits for the device |
| 184 | * to go idle. |
| 185 | */ |
| 186 | spin_lock_irqsave(&conf->resync_lock, flags); |
| 187 | if (!--conf->nr_pending) { |
| 188 | wake_up(&conf->wait_idle); |
| 189 | wake_up(&conf->wait_resume); |
| 190 | } |
| 191 | spin_unlock_irqrestore(&conf->resync_lock, flags); |
| 192 | |
| 193 | put_all_bios(conf, r10_bio); |
| 194 | mempool_free(r10_bio, conf->r10bio_pool); |
| 195 | } |
| 196 | |
| 197 | static inline void put_buf(r10bio_t *r10_bio) |
| 198 | { |
| 199 | conf_t *conf = mddev_to_conf(r10_bio->mddev); |
| 200 | unsigned long flags; |
| 201 | |
| 202 | mempool_free(r10_bio, conf->r10buf_pool); |
| 203 | |
| 204 | spin_lock_irqsave(&conf->resync_lock, flags); |
| 205 | if (!conf->barrier) |
| 206 | BUG(); |
| 207 | --conf->barrier; |
| 208 | wake_up(&conf->wait_resume); |
| 209 | wake_up(&conf->wait_idle); |
| 210 | |
| 211 | if (!--conf->nr_pending) { |
| 212 | wake_up(&conf->wait_idle); |
| 213 | wake_up(&conf->wait_resume); |
| 214 | } |
| 215 | spin_unlock_irqrestore(&conf->resync_lock, flags); |
| 216 | } |
| 217 | |
| 218 | static void reschedule_retry(r10bio_t *r10_bio) |
| 219 | { |
| 220 | unsigned long flags; |
| 221 | mddev_t *mddev = r10_bio->mddev; |
| 222 | conf_t *conf = mddev_to_conf(mddev); |
| 223 | |
| 224 | spin_lock_irqsave(&conf->device_lock, flags); |
| 225 | list_add(&r10_bio->retry_list, &conf->retry_list); |
| 226 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 227 | |
| 228 | md_wakeup_thread(mddev->thread); |
| 229 | } |
| 230 | |
| 231 | /* |
| 232 | * raid_end_bio_io() is called when we have finished servicing a mirrored |
| 233 | * operation and are ready to return a success/failure code to the buffer |
| 234 | * cache layer. |
| 235 | */ |
| 236 | static void raid_end_bio_io(r10bio_t *r10_bio) |
| 237 | { |
| 238 | struct bio *bio = r10_bio->master_bio; |
| 239 | |
| 240 | bio_endio(bio, bio->bi_size, |
| 241 | test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO); |
| 242 | free_r10bio(r10_bio); |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * Update disk head position estimator based on IRQ completion info. |
| 247 | */ |
| 248 | static inline void update_head_pos(int slot, r10bio_t *r10_bio) |
| 249 | { |
| 250 | conf_t *conf = mddev_to_conf(r10_bio->mddev); |
| 251 | |
| 252 | conf->mirrors[r10_bio->devs[slot].devnum].head_position = |
| 253 | r10_bio->devs[slot].addr + (r10_bio->sectors); |
| 254 | } |
| 255 | |
| 256 | static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error) |
| 257 | { |
| 258 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| 259 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); |
| 260 | int slot, dev; |
| 261 | conf_t *conf = mddev_to_conf(r10_bio->mddev); |
| 262 | |
| 263 | if (bio->bi_size) |
| 264 | return 1; |
| 265 | |
| 266 | slot = r10_bio->read_slot; |
| 267 | dev = r10_bio->devs[slot].devnum; |
| 268 | /* |
| 269 | * this branch is our 'one mirror IO has finished' event handler: |
| 270 | */ |
| 271 | if (!uptodate) |
| 272 | md_error(r10_bio->mddev, conf->mirrors[dev].rdev); |
| 273 | else |
| 274 | /* |
| 275 | * Set R10BIO_Uptodate in our master bio, so that |
| 276 | * we will return a good error code to the higher |
| 277 | * levels even if IO on some other mirrored buffer fails. |
| 278 | * |
| 279 | * The 'master' represents the composite IO operation to |
| 280 | * user-side. So if something waits for IO, then it will |
| 281 | * wait for the 'master' bio. |
| 282 | */ |
| 283 | set_bit(R10BIO_Uptodate, &r10_bio->state); |
| 284 | |
| 285 | update_head_pos(slot, r10_bio); |
| 286 | |
| 287 | /* |
| 288 | * we have only one bio on the read side |
| 289 | */ |
| 290 | if (uptodate) |
| 291 | raid_end_bio_io(r10_bio); |
| 292 | else { |
| 293 | /* |
| 294 | * oops, read error: |
| 295 | */ |
| 296 | char b[BDEVNAME_SIZE]; |
| 297 | if (printk_ratelimit()) |
| 298 | printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n", |
| 299 | bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); |
| 300 | reschedule_retry(r10_bio); |
| 301 | } |
| 302 | |
| 303 | rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); |
| 304 | return 0; |
| 305 | } |
| 306 | |
| 307 | static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error) |
| 308 | { |
| 309 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| 310 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); |
| 311 | int slot, dev; |
| 312 | conf_t *conf = mddev_to_conf(r10_bio->mddev); |
| 313 | |
| 314 | if (bio->bi_size) |
| 315 | return 1; |
| 316 | |
| 317 | for (slot = 0; slot < conf->copies; slot++) |
| 318 | if (r10_bio->devs[slot].bio == bio) |
| 319 | break; |
| 320 | dev = r10_bio->devs[slot].devnum; |
| 321 | |
| 322 | /* |
| 323 | * this branch is our 'one mirror IO has finished' event handler: |
| 324 | */ |
| 325 | if (!uptodate) |
| 326 | md_error(r10_bio->mddev, conf->mirrors[dev].rdev); |
| 327 | else |
| 328 | /* |
| 329 | * Set R10BIO_Uptodate in our master bio, so that |
| 330 | * we will return a good error code for to the higher |
| 331 | * levels even if IO on some other mirrored buffer fails. |
| 332 | * |
| 333 | * The 'master' represents the composite IO operation to |
| 334 | * user-side. So if something waits for IO, then it will |
| 335 | * wait for the 'master' bio. |
| 336 | */ |
| 337 | set_bit(R10BIO_Uptodate, &r10_bio->state); |
| 338 | |
| 339 | update_head_pos(slot, r10_bio); |
| 340 | |
| 341 | /* |
| 342 | * |
| 343 | * Let's see if all mirrored write operations have finished |
| 344 | * already. |
| 345 | */ |
| 346 | if (atomic_dec_and_test(&r10_bio->remaining)) { |
| 347 | md_write_end(r10_bio->mddev); |
| 348 | raid_end_bio_io(r10_bio); |
| 349 | } |
| 350 | |
| 351 | rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); |
| 352 | return 0; |
| 353 | } |
| 354 | |
| 355 | |
| 356 | /* |
| 357 | * RAID10 layout manager |
| 358 | * Aswell as the chunksize and raid_disks count, there are two |
| 359 | * parameters: near_copies and far_copies. |
| 360 | * near_copies * far_copies must be <= raid_disks. |
| 361 | * Normally one of these will be 1. |
| 362 | * If both are 1, we get raid0. |
| 363 | * If near_copies == raid_disks, we get raid1. |
| 364 | * |
| 365 | * Chunks are layed out in raid0 style with near_copies copies of the |
| 366 | * first chunk, followed by near_copies copies of the next chunk and |
| 367 | * so on. |
| 368 | * If far_copies > 1, then after 1/far_copies of the array has been assigned |
| 369 | * as described above, we start again with a device offset of near_copies. |
| 370 | * So we effectively have another copy of the whole array further down all |
| 371 | * the drives, but with blocks on different drives. |
| 372 | * With this layout, and block is never stored twice on the one device. |
| 373 | * |
| 374 | * raid10_find_phys finds the sector offset of a given virtual sector |
| 375 | * on each device that it is on. If a block isn't on a device, |
| 376 | * that entry in the array is set to MaxSector. |
| 377 | * |
| 378 | * raid10_find_virt does the reverse mapping, from a device and a |
| 379 | * sector offset to a virtual address |
| 380 | */ |
| 381 | |
| 382 | static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) |
| 383 | { |
| 384 | int n,f; |
| 385 | sector_t sector; |
| 386 | sector_t chunk; |
| 387 | sector_t stripe; |
| 388 | int dev; |
| 389 | |
| 390 | int slot = 0; |
| 391 | |
| 392 | /* now calculate first sector/dev */ |
| 393 | chunk = r10bio->sector >> conf->chunk_shift; |
| 394 | sector = r10bio->sector & conf->chunk_mask; |
| 395 | |
| 396 | chunk *= conf->near_copies; |
| 397 | stripe = chunk; |
| 398 | dev = sector_div(stripe, conf->raid_disks); |
| 399 | |
| 400 | sector += stripe << conf->chunk_shift; |
| 401 | |
| 402 | /* and calculate all the others */ |
| 403 | for (n=0; n < conf->near_copies; n++) { |
| 404 | int d = dev; |
| 405 | sector_t s = sector; |
| 406 | r10bio->devs[slot].addr = sector; |
| 407 | r10bio->devs[slot].devnum = d; |
| 408 | slot++; |
| 409 | |
| 410 | for (f = 1; f < conf->far_copies; f++) { |
| 411 | d += conf->near_copies; |
| 412 | if (d >= conf->raid_disks) |
| 413 | d -= conf->raid_disks; |
| 414 | s += conf->stride; |
| 415 | r10bio->devs[slot].devnum = d; |
| 416 | r10bio->devs[slot].addr = s; |
| 417 | slot++; |
| 418 | } |
| 419 | dev++; |
| 420 | if (dev >= conf->raid_disks) { |
| 421 | dev = 0; |
| 422 | sector += (conf->chunk_mask + 1); |
| 423 | } |
| 424 | } |
| 425 | BUG_ON(slot != conf->copies); |
| 426 | } |
| 427 | |
| 428 | static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) |
| 429 | { |
| 430 | sector_t offset, chunk, vchunk; |
| 431 | |
| 432 | while (sector > conf->stride) { |
| 433 | sector -= conf->stride; |
| 434 | if (dev < conf->near_copies) |
| 435 | dev += conf->raid_disks - conf->near_copies; |
| 436 | else |
| 437 | dev -= conf->near_copies; |
| 438 | } |
| 439 | |
| 440 | offset = sector & conf->chunk_mask; |
| 441 | chunk = sector >> conf->chunk_shift; |
| 442 | vchunk = chunk * conf->raid_disks + dev; |
| 443 | sector_div(vchunk, conf->near_copies); |
| 444 | return (vchunk << conf->chunk_shift) + offset; |
| 445 | } |
| 446 | |
| 447 | /** |
| 448 | * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged |
| 449 | * @q: request queue |
| 450 | * @bio: the buffer head that's been built up so far |
| 451 | * @biovec: the request that could be merged to it. |
| 452 | * |
| 453 | * Return amount of bytes we can accept at this offset |
| 454 | * If near_copies == raid_disk, there are no striping issues, |
| 455 | * but in that case, the function isn't called at all. |
| 456 | */ |
| 457 | static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio, |
| 458 | struct bio_vec *bio_vec) |
| 459 | { |
| 460 | mddev_t *mddev = q->queuedata; |
| 461 | sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); |
| 462 | int max; |
| 463 | unsigned int chunk_sectors = mddev->chunk_size >> 9; |
| 464 | unsigned int bio_sectors = bio->bi_size >> 9; |
| 465 | |
| 466 | max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; |
| 467 | if (max < 0) max = 0; /* bio_add cannot handle a negative return */ |
| 468 | if (max <= bio_vec->bv_len && bio_sectors == 0) |
| 469 | return bio_vec->bv_len; |
| 470 | else |
| 471 | return max; |
| 472 | } |
| 473 | |
| 474 | /* |
| 475 | * This routine returns the disk from which the requested read should |
| 476 | * be done. There is a per-array 'next expected sequential IO' sector |
| 477 | * number - if this matches on the next IO then we use the last disk. |
| 478 | * There is also a per-disk 'last know head position' sector that is |
| 479 | * maintained from IRQ contexts, both the normal and the resync IO |
| 480 | * completion handlers update this position correctly. If there is no |
| 481 | * perfect sequential match then we pick the disk whose head is closest. |
| 482 | * |
| 483 | * If there are 2 mirrors in the same 2 devices, performance degrades |
| 484 | * because position is mirror, not device based. |
| 485 | * |
| 486 | * The rdev for the device selected will have nr_pending incremented. |
| 487 | */ |
| 488 | |
| 489 | /* |
| 490 | * FIXME: possibly should rethink readbalancing and do it differently |
| 491 | * depending on near_copies / far_copies geometry. |
| 492 | */ |
| 493 | static int read_balance(conf_t *conf, r10bio_t *r10_bio) |
| 494 | { |
| 495 | const unsigned long this_sector = r10_bio->sector; |
| 496 | int disk, slot, nslot; |
| 497 | const int sectors = r10_bio->sectors; |
| 498 | sector_t new_distance, current_distance; |
| 499 | |
| 500 | raid10_find_phys(conf, r10_bio); |
| 501 | rcu_read_lock(); |
| 502 | /* |
| 503 | * Check if we can balance. We can balance on the whole |
| 504 | * device if no resync is going on, or below the resync window. |
| 505 | * We take the first readable disk when above the resync window. |
| 506 | */ |
| 507 | if (conf->mddev->recovery_cp < MaxSector |
| 508 | && (this_sector + sectors >= conf->next_resync)) { |
| 509 | /* make sure that disk is operational */ |
| 510 | slot = 0; |
| 511 | disk = r10_bio->devs[slot].devnum; |
| 512 | |
| 513 | while (!conf->mirrors[disk].rdev || |
| 514 | !conf->mirrors[disk].rdev->in_sync) { |
| 515 | slot++; |
| 516 | if (slot == conf->copies) { |
| 517 | slot = 0; |
| 518 | disk = -1; |
| 519 | break; |
| 520 | } |
| 521 | disk = r10_bio->devs[slot].devnum; |
| 522 | } |
| 523 | goto rb_out; |
| 524 | } |
| 525 | |
| 526 | |
| 527 | /* make sure the disk is operational */ |
| 528 | slot = 0; |
| 529 | disk = r10_bio->devs[slot].devnum; |
| 530 | while (!conf->mirrors[disk].rdev || |
| 531 | !conf->mirrors[disk].rdev->in_sync) { |
| 532 | slot ++; |
| 533 | if (slot == conf->copies) { |
| 534 | disk = -1; |
| 535 | goto rb_out; |
| 536 | } |
| 537 | disk = r10_bio->devs[slot].devnum; |
| 538 | } |
| 539 | |
| 540 | |
| 541 | current_distance = abs(this_sector - conf->mirrors[disk].head_position); |
| 542 | |
| 543 | /* Find the disk whose head is closest */ |
| 544 | |
| 545 | for (nslot = slot; nslot < conf->copies; nslot++) { |
| 546 | int ndisk = r10_bio->devs[nslot].devnum; |
| 547 | |
| 548 | |
| 549 | if (!conf->mirrors[ndisk].rdev || |
| 550 | !conf->mirrors[ndisk].rdev->in_sync) |
| 551 | continue; |
| 552 | |
| 553 | if (!atomic_read(&conf->mirrors[ndisk].rdev->nr_pending)) { |
| 554 | disk = ndisk; |
| 555 | slot = nslot; |
| 556 | break; |
| 557 | } |
| 558 | new_distance = abs(r10_bio->devs[nslot].addr - |
| 559 | conf->mirrors[ndisk].head_position); |
| 560 | if (new_distance < current_distance) { |
| 561 | current_distance = new_distance; |
| 562 | disk = ndisk; |
| 563 | slot = nslot; |
| 564 | } |
| 565 | } |
| 566 | |
| 567 | rb_out: |
| 568 | r10_bio->read_slot = slot; |
| 569 | /* conf->next_seq_sect = this_sector + sectors;*/ |
| 570 | |
| 571 | if (disk >= 0 && conf->mirrors[disk].rdev) |
| 572 | atomic_inc(&conf->mirrors[disk].rdev->nr_pending); |
| 573 | rcu_read_unlock(); |
| 574 | |
| 575 | return disk; |
| 576 | } |
| 577 | |
| 578 | static void unplug_slaves(mddev_t *mddev) |
| 579 | { |
| 580 | conf_t *conf = mddev_to_conf(mddev); |
| 581 | int i; |
| 582 | |
| 583 | rcu_read_lock(); |
| 584 | for (i=0; i<mddev->raid_disks; i++) { |
| 585 | mdk_rdev_t *rdev = conf->mirrors[i].rdev; |
| 586 | if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) { |
| 587 | request_queue_t *r_queue = bdev_get_queue(rdev->bdev); |
| 588 | |
| 589 | atomic_inc(&rdev->nr_pending); |
| 590 | rcu_read_unlock(); |
| 591 | |
| 592 | if (r_queue->unplug_fn) |
| 593 | r_queue->unplug_fn(r_queue); |
| 594 | |
| 595 | rdev_dec_pending(rdev, mddev); |
| 596 | rcu_read_lock(); |
| 597 | } |
| 598 | } |
| 599 | rcu_read_unlock(); |
| 600 | } |
| 601 | |
| 602 | static void raid10_unplug(request_queue_t *q) |
| 603 | { |
| 604 | unplug_slaves(q->queuedata); |
| 605 | } |
| 606 | |
| 607 | static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk, |
| 608 | sector_t *error_sector) |
| 609 | { |
| 610 | mddev_t *mddev = q->queuedata; |
| 611 | conf_t *conf = mddev_to_conf(mddev); |
| 612 | int i, ret = 0; |
| 613 | |
| 614 | rcu_read_lock(); |
| 615 | for (i=0; i<mddev->raid_disks && ret == 0; i++) { |
| 616 | mdk_rdev_t *rdev = conf->mirrors[i].rdev; |
| 617 | if (rdev && !rdev->faulty) { |
| 618 | struct block_device *bdev = rdev->bdev; |
| 619 | request_queue_t *r_queue = bdev_get_queue(bdev); |
| 620 | |
| 621 | if (!r_queue->issue_flush_fn) |
| 622 | ret = -EOPNOTSUPP; |
| 623 | else { |
| 624 | atomic_inc(&rdev->nr_pending); |
| 625 | rcu_read_unlock(); |
| 626 | ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, |
| 627 | error_sector); |
| 628 | rdev_dec_pending(rdev, mddev); |
| 629 | rcu_read_lock(); |
| 630 | } |
| 631 | } |
| 632 | } |
| 633 | rcu_read_unlock(); |
| 634 | return ret; |
| 635 | } |
| 636 | |
| 637 | /* |
| 638 | * Throttle resync depth, so that we can both get proper overlapping of |
| 639 | * requests, but are still able to handle normal requests quickly. |
| 640 | */ |
| 641 | #define RESYNC_DEPTH 32 |
| 642 | |
| 643 | static void device_barrier(conf_t *conf, sector_t sect) |
| 644 | { |
| 645 | spin_lock_irq(&conf->resync_lock); |
| 646 | wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume), |
| 647 | conf->resync_lock, unplug_slaves(conf->mddev)); |
| 648 | |
| 649 | if (!conf->barrier++) { |
| 650 | wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, |
| 651 | conf->resync_lock, unplug_slaves(conf->mddev)); |
| 652 | if (conf->nr_pending) |
| 653 | BUG(); |
| 654 | } |
| 655 | wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH, |
| 656 | conf->resync_lock, unplug_slaves(conf->mddev)); |
| 657 | conf->next_resync = sect; |
| 658 | spin_unlock_irq(&conf->resync_lock); |
| 659 | } |
| 660 | |
| 661 | static int make_request(request_queue_t *q, struct bio * bio) |
| 662 | { |
| 663 | mddev_t *mddev = q->queuedata; |
| 664 | conf_t *conf = mddev_to_conf(mddev); |
| 665 | mirror_info_t *mirror; |
| 666 | r10bio_t *r10_bio; |
| 667 | struct bio *read_bio; |
| 668 | int i; |
| 669 | int chunk_sects = conf->chunk_mask + 1; |
| 670 | |
| 671 | /* If this request crosses a chunk boundary, we need to |
| 672 | * split it. This will only happen for 1 PAGE (or less) requests. |
| 673 | */ |
| 674 | if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) |
| 675 | > chunk_sects && |
| 676 | conf->near_copies < conf->raid_disks)) { |
| 677 | struct bio_pair *bp; |
| 678 | /* Sanity check -- queue functions should prevent this happening */ |
| 679 | if (bio->bi_vcnt != 1 || |
| 680 | bio->bi_idx != 0) |
| 681 | goto bad_map; |
| 682 | /* This is a one page bio that upper layers |
| 683 | * refuse to split for us, so we need to split it. |
| 684 | */ |
| 685 | bp = bio_split(bio, bio_split_pool, |
| 686 | chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); |
| 687 | if (make_request(q, &bp->bio1)) |
| 688 | generic_make_request(&bp->bio1); |
| 689 | if (make_request(q, &bp->bio2)) |
| 690 | generic_make_request(&bp->bio2); |
| 691 | |
| 692 | bio_pair_release(bp); |
| 693 | return 0; |
| 694 | bad_map: |
| 695 | printk("raid10_make_request bug: can't convert block across chunks" |
| 696 | " or bigger than %dk %llu %d\n", chunk_sects/2, |
| 697 | (unsigned long long)bio->bi_sector, bio->bi_size >> 10); |
| 698 | |
| 699 | bio_io_error(bio, bio->bi_size); |
| 700 | return 0; |
| 701 | } |
| 702 | |
| 703 | /* |
| 704 | * Register the new request and wait if the reconstruction |
| 705 | * thread has put up a bar for new requests. |
| 706 | * Continue immediately if no resync is active currently. |
| 707 | */ |
| 708 | spin_lock_irq(&conf->resync_lock); |
| 709 | wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, ); |
| 710 | conf->nr_pending++; |
| 711 | spin_unlock_irq(&conf->resync_lock); |
| 712 | |
| 713 | if (bio_data_dir(bio)==WRITE) { |
| 714 | disk_stat_inc(mddev->gendisk, writes); |
| 715 | disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio)); |
| 716 | } else { |
| 717 | disk_stat_inc(mddev->gendisk, reads); |
| 718 | disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio)); |
| 719 | } |
| 720 | |
| 721 | r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); |
| 722 | |
| 723 | r10_bio->master_bio = bio; |
| 724 | r10_bio->sectors = bio->bi_size >> 9; |
| 725 | |
| 726 | r10_bio->mddev = mddev; |
| 727 | r10_bio->sector = bio->bi_sector; |
| 728 | |
| 729 | if (bio_data_dir(bio) == READ) { |
| 730 | /* |
| 731 | * read balancing logic: |
| 732 | */ |
| 733 | int disk = read_balance(conf, r10_bio); |
| 734 | int slot = r10_bio->read_slot; |
| 735 | if (disk < 0) { |
| 736 | raid_end_bio_io(r10_bio); |
| 737 | return 0; |
| 738 | } |
| 739 | mirror = conf->mirrors + disk; |
| 740 | |
| 741 | read_bio = bio_clone(bio, GFP_NOIO); |
| 742 | |
| 743 | r10_bio->devs[slot].bio = read_bio; |
| 744 | |
| 745 | read_bio->bi_sector = r10_bio->devs[slot].addr + |
| 746 | mirror->rdev->data_offset; |
| 747 | read_bio->bi_bdev = mirror->rdev->bdev; |
| 748 | read_bio->bi_end_io = raid10_end_read_request; |
| 749 | read_bio->bi_rw = READ; |
| 750 | read_bio->bi_private = r10_bio; |
| 751 | |
| 752 | generic_make_request(read_bio); |
| 753 | return 0; |
| 754 | } |
| 755 | |
| 756 | /* |
| 757 | * WRITE: |
| 758 | */ |
| 759 | /* first select target devices under spinlock and |
| 760 | * inc refcount on their rdev. Record them by setting |
| 761 | * bios[x] to bio |
| 762 | */ |
| 763 | raid10_find_phys(conf, r10_bio); |
| 764 | rcu_read_lock(); |
| 765 | for (i = 0; i < conf->copies; i++) { |
| 766 | int d = r10_bio->devs[i].devnum; |
| 767 | if (conf->mirrors[d].rdev && |
| 768 | !conf->mirrors[d].rdev->faulty) { |
| 769 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); |
| 770 | r10_bio->devs[i].bio = bio; |
| 771 | } else |
| 772 | r10_bio->devs[i].bio = NULL; |
| 773 | } |
| 774 | rcu_read_unlock(); |
| 775 | |
| 776 | atomic_set(&r10_bio->remaining, 1); |
| 777 | md_write_start(mddev); |
| 778 | for (i = 0; i < conf->copies; i++) { |
| 779 | struct bio *mbio; |
| 780 | int d = r10_bio->devs[i].devnum; |
| 781 | if (!r10_bio->devs[i].bio) |
| 782 | continue; |
| 783 | |
| 784 | mbio = bio_clone(bio, GFP_NOIO); |
| 785 | r10_bio->devs[i].bio = mbio; |
| 786 | |
| 787 | mbio->bi_sector = r10_bio->devs[i].addr+ |
| 788 | conf->mirrors[d].rdev->data_offset; |
| 789 | mbio->bi_bdev = conf->mirrors[d].rdev->bdev; |
| 790 | mbio->bi_end_io = raid10_end_write_request; |
| 791 | mbio->bi_rw = WRITE; |
| 792 | mbio->bi_private = r10_bio; |
| 793 | |
| 794 | atomic_inc(&r10_bio->remaining); |
| 795 | generic_make_request(mbio); |
| 796 | } |
| 797 | |
| 798 | if (atomic_dec_and_test(&r10_bio->remaining)) { |
| 799 | md_write_end(mddev); |
| 800 | raid_end_bio_io(r10_bio); |
| 801 | } |
| 802 | |
| 803 | return 0; |
| 804 | } |
| 805 | |
| 806 | static void status(struct seq_file *seq, mddev_t *mddev) |
| 807 | { |
| 808 | conf_t *conf = mddev_to_conf(mddev); |
| 809 | int i; |
| 810 | |
| 811 | if (conf->near_copies < conf->raid_disks) |
| 812 | seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); |
| 813 | if (conf->near_copies > 1) |
| 814 | seq_printf(seq, " %d near-copies", conf->near_copies); |
| 815 | if (conf->far_copies > 1) |
| 816 | seq_printf(seq, " %d far-copies", conf->far_copies); |
| 817 | |
| 818 | seq_printf(seq, " [%d/%d] [", conf->raid_disks, |
| 819 | conf->working_disks); |
| 820 | for (i = 0; i < conf->raid_disks; i++) |
| 821 | seq_printf(seq, "%s", |
| 822 | conf->mirrors[i].rdev && |
| 823 | conf->mirrors[i].rdev->in_sync ? "U" : "_"); |
| 824 | seq_printf(seq, "]"); |
| 825 | } |
| 826 | |
| 827 | static void error(mddev_t *mddev, mdk_rdev_t *rdev) |
| 828 | { |
| 829 | char b[BDEVNAME_SIZE]; |
| 830 | conf_t *conf = mddev_to_conf(mddev); |
| 831 | |
| 832 | /* |
| 833 | * If it is not operational, then we have already marked it as dead |
| 834 | * else if it is the last working disks, ignore the error, let the |
| 835 | * next level up know. |
| 836 | * else mark the drive as failed |
| 837 | */ |
| 838 | if (rdev->in_sync |
| 839 | && conf->working_disks == 1) |
| 840 | /* |
| 841 | * Don't fail the drive, just return an IO error. |
| 842 | * The test should really be more sophisticated than |
| 843 | * "working_disks == 1", but it isn't critical, and |
| 844 | * can wait until we do more sophisticated "is the drive |
| 845 | * really dead" tests... |
| 846 | */ |
| 847 | return; |
| 848 | if (rdev->in_sync) { |
| 849 | mddev->degraded++; |
| 850 | conf->working_disks--; |
| 851 | /* |
| 852 | * if recovery is running, make sure it aborts. |
| 853 | */ |
| 854 | set_bit(MD_RECOVERY_ERR, &mddev->recovery); |
| 855 | } |
| 856 | rdev->in_sync = 0; |
| 857 | rdev->faulty = 1; |
| 858 | mddev->sb_dirty = 1; |
| 859 | printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n" |
| 860 | " Operation continuing on %d devices\n", |
| 861 | bdevname(rdev->bdev,b), conf->working_disks); |
| 862 | } |
| 863 | |
| 864 | static void print_conf(conf_t *conf) |
| 865 | { |
| 866 | int i; |
| 867 | mirror_info_t *tmp; |
| 868 | |
| 869 | printk("RAID10 conf printout:\n"); |
| 870 | if (!conf) { |
| 871 | printk("(!conf)\n"); |
| 872 | return; |
| 873 | } |
| 874 | printk(" --- wd:%d rd:%d\n", conf->working_disks, |
| 875 | conf->raid_disks); |
| 876 | |
| 877 | for (i = 0; i < conf->raid_disks; i++) { |
| 878 | char b[BDEVNAME_SIZE]; |
| 879 | tmp = conf->mirrors + i; |
| 880 | if (tmp->rdev) |
| 881 | printk(" disk %d, wo:%d, o:%d, dev:%s\n", |
| 882 | i, !tmp->rdev->in_sync, !tmp->rdev->faulty, |
| 883 | bdevname(tmp->rdev->bdev,b)); |
| 884 | } |
| 885 | } |
| 886 | |
| 887 | static void close_sync(conf_t *conf) |
| 888 | { |
| 889 | spin_lock_irq(&conf->resync_lock); |
| 890 | wait_event_lock_irq(conf->wait_resume, !conf->barrier, |
| 891 | conf->resync_lock, unplug_slaves(conf->mddev)); |
| 892 | spin_unlock_irq(&conf->resync_lock); |
| 893 | |
| 894 | if (conf->barrier) BUG(); |
| 895 | if (waitqueue_active(&conf->wait_idle)) BUG(); |
| 896 | |
| 897 | mempool_destroy(conf->r10buf_pool); |
| 898 | conf->r10buf_pool = NULL; |
| 899 | } |
| 900 | |
| 901 | static int raid10_spare_active(mddev_t *mddev) |
| 902 | { |
| 903 | int i; |
| 904 | conf_t *conf = mddev->private; |
| 905 | mirror_info_t *tmp; |
| 906 | |
| 907 | /* |
| 908 | * Find all non-in_sync disks within the RAID10 configuration |
| 909 | * and mark them in_sync |
| 910 | */ |
| 911 | for (i = 0; i < conf->raid_disks; i++) { |
| 912 | tmp = conf->mirrors + i; |
| 913 | if (tmp->rdev |
| 914 | && !tmp->rdev->faulty |
| 915 | && !tmp->rdev->in_sync) { |
| 916 | conf->working_disks++; |
| 917 | mddev->degraded--; |
| 918 | tmp->rdev->in_sync = 1; |
| 919 | } |
| 920 | } |
| 921 | |
| 922 | print_conf(conf); |
| 923 | return 0; |
| 924 | } |
| 925 | |
| 926 | |
| 927 | static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) |
| 928 | { |
| 929 | conf_t *conf = mddev->private; |
| 930 | int found = 0; |
| 931 | int mirror; |
| 932 | mirror_info_t *p; |
| 933 | |
| 934 | if (mddev->recovery_cp < MaxSector) |
| 935 | /* only hot-add to in-sync arrays, as recovery is |
| 936 | * very different from resync |
| 937 | */ |
| 938 | return 0; |
| 939 | |
| 940 | for (mirror=0; mirror < mddev->raid_disks; mirror++) |
| 941 | if ( !(p=conf->mirrors+mirror)->rdev) { |
| 942 | |
| 943 | blk_queue_stack_limits(mddev->queue, |
| 944 | rdev->bdev->bd_disk->queue); |
| 945 | /* as we don't honour merge_bvec_fn, we must never risk |
| 946 | * violating it, so limit ->max_sector to one PAGE, as |
| 947 | * a one page request is never in violation. |
| 948 | */ |
| 949 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && |
| 950 | mddev->queue->max_sectors > (PAGE_SIZE>>9)) |
| 951 | mddev->queue->max_sectors = (PAGE_SIZE>>9); |
| 952 | |
| 953 | p->head_position = 0; |
| 954 | rdev->raid_disk = mirror; |
| 955 | found = 1; |
| 956 | p->rdev = rdev; |
| 957 | break; |
| 958 | } |
| 959 | |
| 960 | print_conf(conf); |
| 961 | return found; |
| 962 | } |
| 963 | |
| 964 | static int raid10_remove_disk(mddev_t *mddev, int number) |
| 965 | { |
| 966 | conf_t *conf = mddev->private; |
| 967 | int err = 0; |
| 968 | mdk_rdev_t *rdev; |
| 969 | mirror_info_t *p = conf->mirrors+ number; |
| 970 | |
| 971 | print_conf(conf); |
| 972 | rdev = p->rdev; |
| 973 | if (rdev) { |
| 974 | if (rdev->in_sync || |
| 975 | atomic_read(&rdev->nr_pending)) { |
| 976 | err = -EBUSY; |
| 977 | goto abort; |
| 978 | } |
| 979 | p->rdev = NULL; |
| 980 | synchronize_kernel(); |
| 981 | if (atomic_read(&rdev->nr_pending)) { |
| 982 | /* lost the race, try later */ |
| 983 | err = -EBUSY; |
| 984 | p->rdev = rdev; |
| 985 | } |
| 986 | } |
| 987 | abort: |
| 988 | |
| 989 | print_conf(conf); |
| 990 | return err; |
| 991 | } |
| 992 | |
| 993 | |
| 994 | static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error) |
| 995 | { |
| 996 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| 997 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); |
| 998 | conf_t *conf = mddev_to_conf(r10_bio->mddev); |
| 999 | int i,d; |
| 1000 | |
| 1001 | if (bio->bi_size) |
| 1002 | return 1; |
| 1003 | |
| 1004 | for (i=0; i<conf->copies; i++) |
| 1005 | if (r10_bio->devs[i].bio == bio) |
| 1006 | break; |
| 1007 | if (i == conf->copies) |
| 1008 | BUG(); |
| 1009 | update_head_pos(i, r10_bio); |
| 1010 | d = r10_bio->devs[i].devnum; |
| 1011 | if (!uptodate) |
| 1012 | md_error(r10_bio->mddev, |
| 1013 | conf->mirrors[d].rdev); |
| 1014 | |
| 1015 | /* for reconstruct, we always reschedule after a read. |
| 1016 | * for resync, only after all reads |
| 1017 | */ |
| 1018 | if (test_bit(R10BIO_IsRecover, &r10_bio->state) || |
| 1019 | atomic_dec_and_test(&r10_bio->remaining)) { |
| 1020 | /* we have read all the blocks, |
| 1021 | * do the comparison in process context in raid10d |
| 1022 | */ |
| 1023 | reschedule_retry(r10_bio); |
| 1024 | } |
| 1025 | rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); |
| 1026 | return 0; |
| 1027 | } |
| 1028 | |
| 1029 | static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error) |
| 1030 | { |
| 1031 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| 1032 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); |
| 1033 | mddev_t *mddev = r10_bio->mddev; |
| 1034 | conf_t *conf = mddev_to_conf(mddev); |
| 1035 | int i,d; |
| 1036 | |
| 1037 | if (bio->bi_size) |
| 1038 | return 1; |
| 1039 | |
| 1040 | for (i = 0; i < conf->copies; i++) |
| 1041 | if (r10_bio->devs[i].bio == bio) |
| 1042 | break; |
| 1043 | d = r10_bio->devs[i].devnum; |
| 1044 | |
| 1045 | if (!uptodate) |
| 1046 | md_error(mddev, conf->mirrors[d].rdev); |
| 1047 | update_head_pos(i, r10_bio); |
| 1048 | |
| 1049 | while (atomic_dec_and_test(&r10_bio->remaining)) { |
| 1050 | if (r10_bio->master_bio == NULL) { |
| 1051 | /* the primary of several recovery bios */ |
| 1052 | md_done_sync(mddev, r10_bio->sectors, 1); |
| 1053 | put_buf(r10_bio); |
| 1054 | break; |
| 1055 | } else { |
| 1056 | r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; |
| 1057 | put_buf(r10_bio); |
| 1058 | r10_bio = r10_bio2; |
| 1059 | } |
| 1060 | } |
| 1061 | rdev_dec_pending(conf->mirrors[d].rdev, mddev); |
| 1062 | return 0; |
| 1063 | } |
| 1064 | |
| 1065 | /* |
| 1066 | * Note: sync and recover and handled very differently for raid10 |
| 1067 | * This code is for resync. |
| 1068 | * For resync, we read through virtual addresses and read all blocks. |
| 1069 | * If there is any error, we schedule a write. The lowest numbered |
| 1070 | * drive is authoritative. |
| 1071 | * However requests come for physical address, so we need to map. |
| 1072 | * For every physical address there are raid_disks/copies virtual addresses, |
| 1073 | * which is always are least one, but is not necessarly an integer. |
| 1074 | * This means that a physical address can span multiple chunks, so we may |
| 1075 | * have to submit multiple io requests for a single sync request. |
| 1076 | */ |
| 1077 | /* |
| 1078 | * We check if all blocks are in-sync and only write to blocks that |
| 1079 | * aren't in sync |
| 1080 | */ |
| 1081 | static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) |
| 1082 | { |
| 1083 | conf_t *conf = mddev_to_conf(mddev); |
| 1084 | int i, first; |
| 1085 | struct bio *tbio, *fbio; |
| 1086 | |
| 1087 | atomic_set(&r10_bio->remaining, 1); |
| 1088 | |
| 1089 | /* find the first device with a block */ |
| 1090 | for (i=0; i<conf->copies; i++) |
| 1091 | if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) |
| 1092 | break; |
| 1093 | |
| 1094 | if (i == conf->copies) |
| 1095 | goto done; |
| 1096 | |
| 1097 | first = i; |
| 1098 | fbio = r10_bio->devs[i].bio; |
| 1099 | |
| 1100 | /* now find blocks with errors */ |
| 1101 | for (i=first+1 ; i < conf->copies ; i++) { |
| 1102 | int vcnt, j, d; |
| 1103 | |
| 1104 | if (!test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) |
| 1105 | continue; |
| 1106 | /* We know that the bi_io_vec layout is the same for |
| 1107 | * both 'first' and 'i', so we just compare them. |
| 1108 | * All vec entries are PAGE_SIZE; |
| 1109 | */ |
| 1110 | tbio = r10_bio->devs[i].bio; |
| 1111 | vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); |
| 1112 | for (j = 0; j < vcnt; j++) |
| 1113 | if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), |
| 1114 | page_address(tbio->bi_io_vec[j].bv_page), |
| 1115 | PAGE_SIZE)) |
| 1116 | break; |
| 1117 | if (j == vcnt) |
| 1118 | continue; |
| 1119 | /* Ok, we need to write this bio |
| 1120 | * First we need to fixup bv_offset, bv_len and |
| 1121 | * bi_vecs, as the read request might have corrupted these |
| 1122 | */ |
| 1123 | tbio->bi_vcnt = vcnt; |
| 1124 | tbio->bi_size = r10_bio->sectors << 9; |
| 1125 | tbio->bi_idx = 0; |
| 1126 | tbio->bi_phys_segments = 0; |
| 1127 | tbio->bi_hw_segments = 0; |
| 1128 | tbio->bi_hw_front_size = 0; |
| 1129 | tbio->bi_hw_back_size = 0; |
| 1130 | tbio->bi_flags &= ~(BIO_POOL_MASK - 1); |
| 1131 | tbio->bi_flags |= 1 << BIO_UPTODATE; |
| 1132 | tbio->bi_next = NULL; |
| 1133 | tbio->bi_rw = WRITE; |
| 1134 | tbio->bi_private = r10_bio; |
| 1135 | tbio->bi_sector = r10_bio->devs[i].addr; |
| 1136 | |
| 1137 | for (j=0; j < vcnt ; j++) { |
| 1138 | tbio->bi_io_vec[j].bv_offset = 0; |
| 1139 | tbio->bi_io_vec[j].bv_len = PAGE_SIZE; |
| 1140 | |
| 1141 | memcpy(page_address(tbio->bi_io_vec[j].bv_page), |
| 1142 | page_address(fbio->bi_io_vec[j].bv_page), |
| 1143 | PAGE_SIZE); |
| 1144 | } |
| 1145 | tbio->bi_end_io = end_sync_write; |
| 1146 | |
| 1147 | d = r10_bio->devs[i].devnum; |
| 1148 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); |
| 1149 | atomic_inc(&r10_bio->remaining); |
| 1150 | md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); |
| 1151 | |
| 1152 | tbio->bi_sector += conf->mirrors[d].rdev->data_offset; |
| 1153 | tbio->bi_bdev = conf->mirrors[d].rdev->bdev; |
| 1154 | generic_make_request(tbio); |
| 1155 | } |
| 1156 | |
| 1157 | done: |
| 1158 | if (atomic_dec_and_test(&r10_bio->remaining)) { |
| 1159 | md_done_sync(mddev, r10_bio->sectors, 1); |
| 1160 | put_buf(r10_bio); |
| 1161 | } |
| 1162 | } |
| 1163 | |
| 1164 | /* |
| 1165 | * Now for the recovery code. |
| 1166 | * Recovery happens across physical sectors. |
| 1167 | * We recover all non-is_sync drives by finding the virtual address of |
| 1168 | * each, and then choose a working drive that also has that virt address. |
| 1169 | * There is a separate r10_bio for each non-in_sync drive. |
| 1170 | * Only the first two slots are in use. The first for reading, |
| 1171 | * The second for writing. |
| 1172 | * |
| 1173 | */ |
| 1174 | |
| 1175 | static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) |
| 1176 | { |
| 1177 | conf_t *conf = mddev_to_conf(mddev); |
| 1178 | int i, d; |
| 1179 | struct bio *bio, *wbio; |
| 1180 | |
| 1181 | |
| 1182 | /* move the pages across to the second bio |
| 1183 | * and submit the write request |
| 1184 | */ |
| 1185 | bio = r10_bio->devs[0].bio; |
| 1186 | wbio = r10_bio->devs[1].bio; |
| 1187 | for (i=0; i < wbio->bi_vcnt; i++) { |
| 1188 | struct page *p = bio->bi_io_vec[i].bv_page; |
| 1189 | bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; |
| 1190 | wbio->bi_io_vec[i].bv_page = p; |
| 1191 | } |
| 1192 | d = r10_bio->devs[1].devnum; |
| 1193 | |
| 1194 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); |
| 1195 | md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); |
| 1196 | generic_make_request(wbio); |
| 1197 | } |
| 1198 | |
| 1199 | |
| 1200 | /* |
| 1201 | * This is a kernel thread which: |
| 1202 | * |
| 1203 | * 1. Retries failed read operations on working mirrors. |
| 1204 | * 2. Updates the raid superblock when problems encounter. |
| 1205 | * 3. Performs writes following reads for array syncronising. |
| 1206 | */ |
| 1207 | |
| 1208 | static void raid10d(mddev_t *mddev) |
| 1209 | { |
| 1210 | r10bio_t *r10_bio; |
| 1211 | struct bio *bio; |
| 1212 | unsigned long flags; |
| 1213 | conf_t *conf = mddev_to_conf(mddev); |
| 1214 | struct list_head *head = &conf->retry_list; |
| 1215 | int unplug=0; |
| 1216 | mdk_rdev_t *rdev; |
| 1217 | |
| 1218 | md_check_recovery(mddev); |
| 1219 | md_handle_safemode(mddev); |
| 1220 | |
| 1221 | for (;;) { |
| 1222 | char b[BDEVNAME_SIZE]; |
| 1223 | spin_lock_irqsave(&conf->device_lock, flags); |
| 1224 | if (list_empty(head)) |
| 1225 | break; |
| 1226 | r10_bio = list_entry(head->prev, r10bio_t, retry_list); |
| 1227 | list_del(head->prev); |
| 1228 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 1229 | |
| 1230 | mddev = r10_bio->mddev; |
| 1231 | conf = mddev_to_conf(mddev); |
| 1232 | if (test_bit(R10BIO_IsSync, &r10_bio->state)) { |
| 1233 | sync_request_write(mddev, r10_bio); |
| 1234 | unplug = 1; |
| 1235 | } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { |
| 1236 | recovery_request_write(mddev, r10_bio); |
| 1237 | unplug = 1; |
| 1238 | } else { |
| 1239 | int mirror; |
| 1240 | bio = r10_bio->devs[r10_bio->read_slot].bio; |
| 1241 | r10_bio->devs[r10_bio->read_slot].bio = NULL; |
| 1242 | bio_put(bio); |
| 1243 | mirror = read_balance(conf, r10_bio); |
| 1244 | if (mirror == -1) { |
| 1245 | printk(KERN_ALERT "raid10: %s: unrecoverable I/O" |
| 1246 | " read error for block %llu\n", |
| 1247 | bdevname(bio->bi_bdev,b), |
| 1248 | (unsigned long long)r10_bio->sector); |
| 1249 | raid_end_bio_io(r10_bio); |
| 1250 | } else { |
| 1251 | rdev = conf->mirrors[mirror].rdev; |
| 1252 | if (printk_ratelimit()) |
| 1253 | printk(KERN_ERR "raid10: %s: redirecting sector %llu to" |
| 1254 | " another mirror\n", |
| 1255 | bdevname(rdev->bdev,b), |
| 1256 | (unsigned long long)r10_bio->sector); |
| 1257 | bio = bio_clone(r10_bio->master_bio, GFP_NOIO); |
| 1258 | r10_bio->devs[r10_bio->read_slot].bio = bio; |
| 1259 | bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr |
| 1260 | + rdev->data_offset; |
| 1261 | bio->bi_bdev = rdev->bdev; |
| 1262 | bio->bi_rw = READ; |
| 1263 | bio->bi_private = r10_bio; |
| 1264 | bio->bi_end_io = raid10_end_read_request; |
| 1265 | unplug = 1; |
| 1266 | generic_make_request(bio); |
| 1267 | } |
| 1268 | } |
| 1269 | } |
| 1270 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 1271 | if (unplug) |
| 1272 | unplug_slaves(mddev); |
| 1273 | } |
| 1274 | |
| 1275 | |
| 1276 | static int init_resync(conf_t *conf) |
| 1277 | { |
| 1278 | int buffs; |
| 1279 | |
| 1280 | buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; |
| 1281 | if (conf->r10buf_pool) |
| 1282 | BUG(); |
| 1283 | conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); |
| 1284 | if (!conf->r10buf_pool) |
| 1285 | return -ENOMEM; |
| 1286 | conf->next_resync = 0; |
| 1287 | return 0; |
| 1288 | } |
| 1289 | |
| 1290 | /* |
| 1291 | * perform a "sync" on one "block" |
| 1292 | * |
| 1293 | * We need to make sure that no normal I/O request - particularly write |
| 1294 | * requests - conflict with active sync requests. |
| 1295 | * |
| 1296 | * This is achieved by tracking pending requests and a 'barrier' concept |
| 1297 | * that can be installed to exclude normal IO requests. |
| 1298 | * |
| 1299 | * Resync and recovery are handled very differently. |
| 1300 | * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. |
| 1301 | * |
| 1302 | * For resync, we iterate over virtual addresses, read all copies, |
| 1303 | * and update if there are differences. If only one copy is live, |
| 1304 | * skip it. |
| 1305 | * For recovery, we iterate over physical addresses, read a good |
| 1306 | * value for each non-in_sync drive, and over-write. |
| 1307 | * |
| 1308 | * So, for recovery we may have several outstanding complex requests for a |
| 1309 | * given address, one for each out-of-sync device. We model this by allocating |
| 1310 | * a number of r10_bio structures, one for each out-of-sync device. |
| 1311 | * As we setup these structures, we collect all bio's together into a list |
| 1312 | * which we then process collectively to add pages, and then process again |
| 1313 | * to pass to generic_make_request. |
| 1314 | * |
| 1315 | * The r10_bio structures are linked using a borrowed master_bio pointer. |
| 1316 | * This link is counted in ->remaining. When the r10_bio that points to NULL |
| 1317 | * has its remaining count decremented to 0, the whole complex operation |
| 1318 | * is complete. |
| 1319 | * |
| 1320 | */ |
| 1321 | |
| 1322 | static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster) |
| 1323 | { |
| 1324 | conf_t *conf = mddev_to_conf(mddev); |
| 1325 | r10bio_t *r10_bio; |
| 1326 | struct bio *biolist = NULL, *bio; |
| 1327 | sector_t max_sector, nr_sectors; |
| 1328 | int disk; |
| 1329 | int i; |
| 1330 | |
| 1331 | sector_t sectors_skipped = 0; |
| 1332 | int chunks_skipped = 0; |
| 1333 | |
| 1334 | if (!conf->r10buf_pool) |
| 1335 | if (init_resync(conf)) |
| 1336 | return -ENOMEM; |
| 1337 | |
| 1338 | skipped: |
| 1339 | max_sector = mddev->size << 1; |
| 1340 | if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) |
| 1341 | max_sector = mddev->resync_max_sectors; |
| 1342 | if (sector_nr >= max_sector) { |
| 1343 | close_sync(conf); |
| 1344 | return sectors_skipped; |
| 1345 | } |
| 1346 | if (chunks_skipped >= conf->raid_disks) { |
| 1347 | /* if there has been nothing to do on any drive, |
| 1348 | * then there is nothing to do at all.. |
| 1349 | */ |
| 1350 | sector_t sec = max_sector - sector_nr; |
| 1351 | md_done_sync(mddev, sec, 1); |
| 1352 | return sec + sectors_skipped; |
| 1353 | } |
| 1354 | |
| 1355 | /* make sure whole request will fit in a chunk - if chunks |
| 1356 | * are meaningful |
| 1357 | */ |
| 1358 | if (conf->near_copies < conf->raid_disks && |
| 1359 | max_sector > (sector_nr | conf->chunk_mask)) |
| 1360 | max_sector = (sector_nr | conf->chunk_mask) + 1; |
| 1361 | /* |
| 1362 | * If there is non-resync activity waiting for us then |
| 1363 | * put in a delay to throttle resync. |
| 1364 | */ |
| 1365 | if (!go_faster && waitqueue_active(&conf->wait_resume)) |
| 1366 | msleep_interruptible(1000); |
| 1367 | device_barrier(conf, sector_nr + RESYNC_SECTORS); |
| 1368 | |
| 1369 | /* Again, very different code for resync and recovery. |
| 1370 | * Both must result in an r10bio with a list of bios that |
| 1371 | * have bi_end_io, bi_sector, bi_bdev set, |
| 1372 | * and bi_private set to the r10bio. |
| 1373 | * For recovery, we may actually create several r10bios |
| 1374 | * with 2 bios in each, that correspond to the bios in the main one. |
| 1375 | * In this case, the subordinate r10bios link back through a |
| 1376 | * borrowed master_bio pointer, and the counter in the master |
| 1377 | * includes a ref from each subordinate. |
| 1378 | */ |
| 1379 | /* First, we decide what to do and set ->bi_end_io |
| 1380 | * To end_sync_read if we want to read, and |
| 1381 | * end_sync_write if we will want to write. |
| 1382 | */ |
| 1383 | |
| 1384 | if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { |
| 1385 | /* recovery... the complicated one */ |
| 1386 | int i, j, k; |
| 1387 | r10_bio = NULL; |
| 1388 | |
| 1389 | for (i=0 ; i<conf->raid_disks; i++) |
| 1390 | if (conf->mirrors[i].rdev && |
| 1391 | !conf->mirrors[i].rdev->in_sync) { |
| 1392 | /* want to reconstruct this device */ |
| 1393 | r10bio_t *rb2 = r10_bio; |
| 1394 | |
| 1395 | r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); |
| 1396 | spin_lock_irq(&conf->resync_lock); |
| 1397 | conf->nr_pending++; |
| 1398 | if (rb2) conf->barrier++; |
| 1399 | spin_unlock_irq(&conf->resync_lock); |
| 1400 | atomic_set(&r10_bio->remaining, 0); |
| 1401 | |
| 1402 | r10_bio->master_bio = (struct bio*)rb2; |
| 1403 | if (rb2) |
| 1404 | atomic_inc(&rb2->remaining); |
| 1405 | r10_bio->mddev = mddev; |
| 1406 | set_bit(R10BIO_IsRecover, &r10_bio->state); |
| 1407 | r10_bio->sector = raid10_find_virt(conf, sector_nr, i); |
| 1408 | raid10_find_phys(conf, r10_bio); |
| 1409 | for (j=0; j<conf->copies;j++) { |
| 1410 | int d = r10_bio->devs[j].devnum; |
| 1411 | if (conf->mirrors[d].rdev && |
| 1412 | conf->mirrors[d].rdev->in_sync) { |
| 1413 | /* This is where we read from */ |
| 1414 | bio = r10_bio->devs[0].bio; |
| 1415 | bio->bi_next = biolist; |
| 1416 | biolist = bio; |
| 1417 | bio->bi_private = r10_bio; |
| 1418 | bio->bi_end_io = end_sync_read; |
| 1419 | bio->bi_rw = 0; |
| 1420 | bio->bi_sector = r10_bio->devs[j].addr + |
| 1421 | conf->mirrors[d].rdev->data_offset; |
| 1422 | bio->bi_bdev = conf->mirrors[d].rdev->bdev; |
| 1423 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); |
| 1424 | atomic_inc(&r10_bio->remaining); |
| 1425 | /* and we write to 'i' */ |
| 1426 | |
| 1427 | for (k=0; k<conf->copies; k++) |
| 1428 | if (r10_bio->devs[k].devnum == i) |
| 1429 | break; |
| 1430 | bio = r10_bio->devs[1].bio; |
| 1431 | bio->bi_next = biolist; |
| 1432 | biolist = bio; |
| 1433 | bio->bi_private = r10_bio; |
| 1434 | bio->bi_end_io = end_sync_write; |
| 1435 | bio->bi_rw = 1; |
| 1436 | bio->bi_sector = r10_bio->devs[k].addr + |
| 1437 | conf->mirrors[i].rdev->data_offset; |
| 1438 | bio->bi_bdev = conf->mirrors[i].rdev->bdev; |
| 1439 | |
| 1440 | r10_bio->devs[0].devnum = d; |
| 1441 | r10_bio->devs[1].devnum = i; |
| 1442 | |
| 1443 | break; |
| 1444 | } |
| 1445 | } |
| 1446 | if (j == conf->copies) { |
| 1447 | BUG(); |
| 1448 | } |
| 1449 | } |
| 1450 | if (biolist == NULL) { |
| 1451 | while (r10_bio) { |
| 1452 | r10bio_t *rb2 = r10_bio; |
| 1453 | r10_bio = (r10bio_t*) rb2->master_bio; |
| 1454 | rb2->master_bio = NULL; |
| 1455 | put_buf(rb2); |
| 1456 | } |
| 1457 | goto giveup; |
| 1458 | } |
| 1459 | } else { |
| 1460 | /* resync. Schedule a read for every block at this virt offset */ |
| 1461 | int count = 0; |
| 1462 | r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); |
| 1463 | |
| 1464 | spin_lock_irq(&conf->resync_lock); |
| 1465 | conf->nr_pending++; |
| 1466 | spin_unlock_irq(&conf->resync_lock); |
| 1467 | |
| 1468 | r10_bio->mddev = mddev; |
| 1469 | atomic_set(&r10_bio->remaining, 0); |
| 1470 | |
| 1471 | r10_bio->master_bio = NULL; |
| 1472 | r10_bio->sector = sector_nr; |
| 1473 | set_bit(R10BIO_IsSync, &r10_bio->state); |
| 1474 | raid10_find_phys(conf, r10_bio); |
| 1475 | r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; |
| 1476 | |
| 1477 | for (i=0; i<conf->copies; i++) { |
| 1478 | int d = r10_bio->devs[i].devnum; |
| 1479 | bio = r10_bio->devs[i].bio; |
| 1480 | bio->bi_end_io = NULL; |
| 1481 | if (conf->mirrors[d].rdev == NULL || |
| 1482 | conf->mirrors[d].rdev->faulty) |
| 1483 | continue; |
| 1484 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); |
| 1485 | atomic_inc(&r10_bio->remaining); |
| 1486 | bio->bi_next = biolist; |
| 1487 | biolist = bio; |
| 1488 | bio->bi_private = r10_bio; |
| 1489 | bio->bi_end_io = end_sync_read; |
| 1490 | bio->bi_rw = 0; |
| 1491 | bio->bi_sector = r10_bio->devs[i].addr + |
| 1492 | conf->mirrors[d].rdev->data_offset; |
| 1493 | bio->bi_bdev = conf->mirrors[d].rdev->bdev; |
| 1494 | count++; |
| 1495 | } |
| 1496 | |
| 1497 | if (count < 2) { |
| 1498 | for (i=0; i<conf->copies; i++) { |
| 1499 | int d = r10_bio->devs[i].devnum; |
| 1500 | if (r10_bio->devs[i].bio->bi_end_io) |
| 1501 | rdev_dec_pending(conf->mirrors[d].rdev, mddev); |
| 1502 | } |
| 1503 | put_buf(r10_bio); |
| 1504 | biolist = NULL; |
| 1505 | goto giveup; |
| 1506 | } |
| 1507 | } |
| 1508 | |
| 1509 | for (bio = biolist; bio ; bio=bio->bi_next) { |
| 1510 | |
| 1511 | bio->bi_flags &= ~(BIO_POOL_MASK - 1); |
| 1512 | if (bio->bi_end_io) |
| 1513 | bio->bi_flags |= 1 << BIO_UPTODATE; |
| 1514 | bio->bi_vcnt = 0; |
| 1515 | bio->bi_idx = 0; |
| 1516 | bio->bi_phys_segments = 0; |
| 1517 | bio->bi_hw_segments = 0; |
| 1518 | bio->bi_size = 0; |
| 1519 | } |
| 1520 | |
| 1521 | nr_sectors = 0; |
| 1522 | do { |
| 1523 | struct page *page; |
| 1524 | int len = PAGE_SIZE; |
| 1525 | disk = 0; |
| 1526 | if (sector_nr + (len>>9) > max_sector) |
| 1527 | len = (max_sector - sector_nr) << 9; |
| 1528 | if (len == 0) |
| 1529 | break; |
| 1530 | for (bio= biolist ; bio ; bio=bio->bi_next) { |
| 1531 | page = bio->bi_io_vec[bio->bi_vcnt].bv_page; |
| 1532 | if (bio_add_page(bio, page, len, 0) == 0) { |
| 1533 | /* stop here */ |
| 1534 | struct bio *bio2; |
| 1535 | bio->bi_io_vec[bio->bi_vcnt].bv_page = page; |
| 1536 | for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { |
| 1537 | /* remove last page from this bio */ |
| 1538 | bio2->bi_vcnt--; |
| 1539 | bio2->bi_size -= len; |
| 1540 | bio2->bi_flags &= ~(1<< BIO_SEG_VALID); |
| 1541 | } |
| 1542 | goto bio_full; |
| 1543 | } |
| 1544 | disk = i; |
| 1545 | } |
| 1546 | nr_sectors += len>>9; |
| 1547 | sector_nr += len>>9; |
| 1548 | } while (biolist->bi_vcnt < RESYNC_PAGES); |
| 1549 | bio_full: |
| 1550 | r10_bio->sectors = nr_sectors; |
| 1551 | |
| 1552 | while (biolist) { |
| 1553 | bio = biolist; |
| 1554 | biolist = biolist->bi_next; |
| 1555 | |
| 1556 | bio->bi_next = NULL; |
| 1557 | r10_bio = bio->bi_private; |
| 1558 | r10_bio->sectors = nr_sectors; |
| 1559 | |
| 1560 | if (bio->bi_end_io == end_sync_read) { |
| 1561 | md_sync_acct(bio->bi_bdev, nr_sectors); |
| 1562 | generic_make_request(bio); |
| 1563 | } |
| 1564 | } |
| 1565 | |
| 1566 | return sectors_skipped + nr_sectors; |
| 1567 | giveup: |
| 1568 | /* There is nowhere to write, so all non-sync |
| 1569 | * drives must be failed, so try the next chunk... |
| 1570 | */ |
| 1571 | { |
| 1572 | int sec = max_sector - sector_nr; |
| 1573 | sectors_skipped += sec; |
| 1574 | chunks_skipped ++; |
| 1575 | sector_nr = max_sector; |
| 1576 | md_done_sync(mddev, sec, 1); |
| 1577 | goto skipped; |
| 1578 | } |
| 1579 | } |
| 1580 | |
| 1581 | static int run(mddev_t *mddev) |
| 1582 | { |
| 1583 | conf_t *conf; |
| 1584 | int i, disk_idx; |
| 1585 | mirror_info_t *disk; |
| 1586 | mdk_rdev_t *rdev; |
| 1587 | struct list_head *tmp; |
| 1588 | int nc, fc; |
| 1589 | sector_t stride, size; |
| 1590 | |
| 1591 | if (mddev->level != 10) { |
| 1592 | printk(KERN_ERR "raid10: %s: raid level not set correctly... (%d)\n", |
| 1593 | mdname(mddev), mddev->level); |
| 1594 | goto out; |
| 1595 | } |
| 1596 | nc = mddev->layout & 255; |
| 1597 | fc = (mddev->layout >> 8) & 255; |
| 1598 | if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || |
| 1599 | (mddev->layout >> 16)) { |
| 1600 | printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", |
| 1601 | mdname(mddev), mddev->layout); |
| 1602 | goto out; |
| 1603 | } |
| 1604 | /* |
| 1605 | * copy the already verified devices into our private RAID10 |
| 1606 | * bookkeeping area. [whatever we allocate in run(), |
| 1607 | * should be freed in stop()] |
| 1608 | */ |
| 1609 | conf = kmalloc(sizeof(conf_t), GFP_KERNEL); |
| 1610 | mddev->private = conf; |
| 1611 | if (!conf) { |
| 1612 | printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", |
| 1613 | mdname(mddev)); |
| 1614 | goto out; |
| 1615 | } |
| 1616 | memset(conf, 0, sizeof(*conf)); |
| 1617 | conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks, |
| 1618 | GFP_KERNEL); |
| 1619 | if (!conf->mirrors) { |
| 1620 | printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", |
| 1621 | mdname(mddev)); |
| 1622 | goto out_free_conf; |
| 1623 | } |
| 1624 | memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks); |
| 1625 | |
| 1626 | conf->near_copies = nc; |
| 1627 | conf->far_copies = fc; |
| 1628 | conf->copies = nc*fc; |
| 1629 | conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; |
| 1630 | conf->chunk_shift = ffz(~mddev->chunk_size) - 9; |
| 1631 | stride = mddev->size >> (conf->chunk_shift-1); |
| 1632 | sector_div(stride, fc); |
| 1633 | conf->stride = stride << conf->chunk_shift; |
| 1634 | |
| 1635 | conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, |
| 1636 | r10bio_pool_free, conf); |
| 1637 | if (!conf->r10bio_pool) { |
| 1638 | printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", |
| 1639 | mdname(mddev)); |
| 1640 | goto out_free_conf; |
| 1641 | } |
| 1642 | mddev->queue->unplug_fn = raid10_unplug; |
| 1643 | |
| 1644 | mddev->queue->issue_flush_fn = raid10_issue_flush; |
| 1645 | |
| 1646 | ITERATE_RDEV(mddev, rdev, tmp) { |
| 1647 | disk_idx = rdev->raid_disk; |
| 1648 | if (disk_idx >= mddev->raid_disks |
| 1649 | || disk_idx < 0) |
| 1650 | continue; |
| 1651 | disk = conf->mirrors + disk_idx; |
| 1652 | |
| 1653 | disk->rdev = rdev; |
| 1654 | |
| 1655 | blk_queue_stack_limits(mddev->queue, |
| 1656 | rdev->bdev->bd_disk->queue); |
| 1657 | /* as we don't honour merge_bvec_fn, we must never risk |
| 1658 | * violating it, so limit ->max_sector to one PAGE, as |
| 1659 | * a one page request is never in violation. |
| 1660 | */ |
| 1661 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && |
| 1662 | mddev->queue->max_sectors > (PAGE_SIZE>>9)) |
| 1663 | mddev->queue->max_sectors = (PAGE_SIZE>>9); |
| 1664 | |
| 1665 | disk->head_position = 0; |
| 1666 | if (!rdev->faulty && rdev->in_sync) |
| 1667 | conf->working_disks++; |
| 1668 | } |
| 1669 | conf->raid_disks = mddev->raid_disks; |
| 1670 | conf->mddev = mddev; |
| 1671 | spin_lock_init(&conf->device_lock); |
| 1672 | INIT_LIST_HEAD(&conf->retry_list); |
| 1673 | |
| 1674 | spin_lock_init(&conf->resync_lock); |
| 1675 | init_waitqueue_head(&conf->wait_idle); |
| 1676 | init_waitqueue_head(&conf->wait_resume); |
| 1677 | |
| 1678 | if (!conf->working_disks) { |
| 1679 | printk(KERN_ERR "raid10: no operational mirrors for %s\n", |
| 1680 | mdname(mddev)); |
| 1681 | goto out_free_conf; |
| 1682 | } |
| 1683 | |
| 1684 | mddev->degraded = 0; |
| 1685 | for (i = 0; i < conf->raid_disks; i++) { |
| 1686 | |
| 1687 | disk = conf->mirrors + i; |
| 1688 | |
| 1689 | if (!disk->rdev) { |
| 1690 | disk->head_position = 0; |
| 1691 | mddev->degraded++; |
| 1692 | } |
| 1693 | } |
| 1694 | |
| 1695 | |
| 1696 | mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10"); |
| 1697 | if (!mddev->thread) { |
| 1698 | printk(KERN_ERR |
| 1699 | "raid10: couldn't allocate thread for %s\n", |
| 1700 | mdname(mddev)); |
| 1701 | goto out_free_conf; |
| 1702 | } |
| 1703 | |
| 1704 | printk(KERN_INFO |
| 1705 | "raid10: raid set %s active with %d out of %d devices\n", |
| 1706 | mdname(mddev), mddev->raid_disks - mddev->degraded, |
| 1707 | mddev->raid_disks); |
| 1708 | /* |
| 1709 | * Ok, everything is just fine now |
| 1710 | */ |
| 1711 | size = conf->stride * conf->raid_disks; |
| 1712 | sector_div(size, conf->near_copies); |
| 1713 | mddev->array_size = size/2; |
| 1714 | mddev->resync_max_sectors = size; |
| 1715 | |
| 1716 | /* Calculate max read-ahead size. |
| 1717 | * We need to readahead at least twice a whole stripe.... |
| 1718 | * maybe... |
| 1719 | */ |
| 1720 | { |
| 1721 | int stripe = conf->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE; |
| 1722 | stripe /= conf->near_copies; |
| 1723 | if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) |
| 1724 | mddev->queue->backing_dev_info.ra_pages = 2* stripe; |
| 1725 | } |
| 1726 | |
| 1727 | if (conf->near_copies < mddev->raid_disks) |
| 1728 | blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); |
| 1729 | return 0; |
| 1730 | |
| 1731 | out_free_conf: |
| 1732 | if (conf->r10bio_pool) |
| 1733 | mempool_destroy(conf->r10bio_pool); |
| 1734 | if (conf->mirrors) |
| 1735 | kfree(conf->mirrors); |
| 1736 | kfree(conf); |
| 1737 | mddev->private = NULL; |
| 1738 | out: |
| 1739 | return -EIO; |
| 1740 | } |
| 1741 | |
| 1742 | static int stop(mddev_t *mddev) |
| 1743 | { |
| 1744 | conf_t *conf = mddev_to_conf(mddev); |
| 1745 | |
| 1746 | md_unregister_thread(mddev->thread); |
| 1747 | mddev->thread = NULL; |
| 1748 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
| 1749 | if (conf->r10bio_pool) |
| 1750 | mempool_destroy(conf->r10bio_pool); |
| 1751 | if (conf->mirrors) |
| 1752 | kfree(conf->mirrors); |
| 1753 | kfree(conf); |
| 1754 | mddev->private = NULL; |
| 1755 | return 0; |
| 1756 | } |
| 1757 | |
| 1758 | |
| 1759 | static mdk_personality_t raid10_personality = |
| 1760 | { |
| 1761 | .name = "raid10", |
| 1762 | .owner = THIS_MODULE, |
| 1763 | .make_request = make_request, |
| 1764 | .run = run, |
| 1765 | .stop = stop, |
| 1766 | .status = status, |
| 1767 | .error_handler = error, |
| 1768 | .hot_add_disk = raid10_add_disk, |
| 1769 | .hot_remove_disk= raid10_remove_disk, |
| 1770 | .spare_active = raid10_spare_active, |
| 1771 | .sync_request = sync_request, |
| 1772 | }; |
| 1773 | |
| 1774 | static int __init raid_init(void) |
| 1775 | { |
| 1776 | return register_md_personality(RAID10, &raid10_personality); |
| 1777 | } |
| 1778 | |
| 1779 | static void raid_exit(void) |
| 1780 | { |
| 1781 | unregister_md_personality(RAID10); |
| 1782 | } |
| 1783 | |
| 1784 | module_init(raid_init); |
| 1785 | module_exit(raid_exit); |
| 1786 | MODULE_LICENSE("GPL"); |
| 1787 | MODULE_ALIAS("md-personality-9"); /* RAID10 */ |