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 "dm-bio-list.h" 22#include <linux/raid/raid10.h> 23#include <linux/raid/bitmap.h> 24 25/* 26 * RAID10 provides a combination of RAID0 and RAID1 functionality. 27 * The layout of data is defined by 28 * chunk_size 29 * raid_disks 30 * near_copies (stored in low byte of layout) 31 * far_copies (stored in second byte of layout) 32 * far_offset (stored in bit 16 of layout ) 33 * 34 * The data to be stored is divided into chunks using chunksize. 35 * Each device is divided into far_copies sections. 36 * In each section, chunks are laid out in a style similar to raid0, but 37 * near_copies copies of each chunk is stored (each on a different drive). 38 * The starting device for each section is offset near_copies from the starting 39 * device of the previous section. 40 * Thus they are (near_copies*far_copies) of each chunk, and each is on a different 41 * drive. 42 * near_copies and far_copies must be at least one, and their product is at most 43 * raid_disks. 44 * 45 * If far_offset is true, then the far_copies are handled a bit differently. 46 * The copies are still in different stripes, but instead of be very far apart 47 * on disk, there are adjacent stripes. 48 */ 49 50/* 51 * Number of guaranteed r10bios in case of extreme VM load: 52 */ 53#define NR_RAID10_BIOS 256 54 55static void unplug_slaves(mddev_t *mddev); 56 57static void allow_barrier(conf_t *conf); 58static void lower_barrier(conf_t *conf); 59 60static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) 61{ 62 conf_t *conf = data; 63 r10bio_t *r10_bio; 64 int size = offsetof(struct r10bio_s, devs[conf->copies]); 65 66 /* allocate a r10bio with room for raid_disks entries in the bios array */ 67 r10_bio = kzalloc(size, gfp_flags); 68 if (!r10_bio) 69 unplug_slaves(conf->mddev); 70 71 return r10_bio; 72} 73 74static void r10bio_pool_free(void *r10_bio, void *data) 75{ 76 kfree(r10_bio); 77} 78 79#define RESYNC_BLOCK_SIZE (64*1024) 80//#define RESYNC_BLOCK_SIZE PAGE_SIZE 81#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) 82#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) 83#define RESYNC_WINDOW (2048*1024) 84 85/* 86 * When performing a resync, we need to read and compare, so 87 * we need as many pages are there are copies. 88 * When performing a recovery, we need 2 bios, one for read, 89 * one for write (we recover only one drive per r10buf) 90 * 91 */ 92static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data) 93{ 94 conf_t *conf = data; 95 struct page *page; 96 r10bio_t *r10_bio; 97 struct bio *bio; 98 int i, j; 99 int nalloc; 100 101 r10_bio = r10bio_pool_alloc(gfp_flags, conf); 102 if (!r10_bio) { 103 unplug_slaves(conf->mddev); 104 return NULL; 105 } 106 107 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) 108 nalloc = conf->copies; /* resync */ 109 else 110 nalloc = 2; /* recovery */ 111 112 /* 113 * Allocate bios. 114 */ 115 for (j = nalloc ; j-- ; ) { 116 bio = bio_alloc(gfp_flags, RESYNC_PAGES); 117 if (!bio) 118 goto out_free_bio; 119 r10_bio->devs[j].bio = bio; 120 } 121 /* 122 * Allocate RESYNC_PAGES data pages and attach them 123 * where needed. 124 */ 125 for (j = 0 ; j < nalloc; j++) { 126 bio = r10_bio->devs[j].bio; 127 for (i = 0; i < RESYNC_PAGES; i++) { 128 page = alloc_page(gfp_flags); 129 if (unlikely(!page)) 130 goto out_free_pages; 131 132 bio->bi_io_vec[i].bv_page = page; 133 } 134 } 135 136 return r10_bio; 137 138out_free_pages: 139 for ( ; i > 0 ; i--) 140 safe_put_page(bio->bi_io_vec[i-1].bv_page); 141 while (j--) 142 for (i = 0; i < RESYNC_PAGES ; i++) 143 safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page); 144 j = -1; 145out_free_bio: 146 while ( ++j < nalloc ) 147 bio_put(r10_bio->devs[j].bio); 148 r10bio_pool_free(r10_bio, conf); 149 return NULL; 150} 151 152static void r10buf_pool_free(void *__r10_bio, void *data) 153{ 154 int i; 155 conf_t *conf = data; 156 r10bio_t *r10bio = __r10_bio; 157 int j; 158 159 for (j=0; j < conf->copies; j++) { 160 struct bio *bio = r10bio->devs[j].bio; 161 if (bio) { 162 for (i = 0; i < RESYNC_PAGES; i++) { 163 safe_put_page(bio->bi_io_vec[i].bv_page); 164 bio->bi_io_vec[i].bv_page = NULL; 165 } 166 bio_put(bio); 167 } 168 } 169 r10bio_pool_free(r10bio, conf); 170} 171 172static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) 173{ 174 int i; 175 176 for (i = 0; i < conf->copies; i++) { 177 struct bio **bio = & r10_bio->devs[i].bio; 178 if (*bio && *bio != IO_BLOCKED) 179 bio_put(*bio); 180 *bio = NULL; 181 } 182} 183 184static void free_r10bio(r10bio_t *r10_bio) 185{ 186 conf_t *conf = mddev_to_conf(r10_bio->mddev); 187 188 /* 189 * Wake up any possible resync thread that waits for the device 190 * to go idle. 191 */ 192 allow_barrier(conf); 193 194 put_all_bios(conf, r10_bio); 195 mempool_free(r10_bio, conf->r10bio_pool); 196} 197 198static void put_buf(r10bio_t *r10_bio) 199{ 200 conf_t *conf = mddev_to_conf(r10_bio->mddev); 201 202 mempool_free(r10_bio, conf->r10buf_pool); 203 204 lower_barrier(conf); 205} 206 207static void reschedule_retry(r10bio_t *r10_bio) 208{ 209 unsigned long flags; 210 mddev_t *mddev = r10_bio->mddev; 211 conf_t *conf = mddev_to_conf(mddev); 212 213 spin_lock_irqsave(&conf->device_lock, flags); 214 list_add(&r10_bio->retry_list, &conf->retry_list); 215 conf->nr_queued ++; 216 spin_unlock_irqrestore(&conf->device_lock, flags); 217 218 md_wakeup_thread(mddev->thread); 219} 220 221/* 222 * raid_end_bio_io() is called when we have finished servicing a mirrored 223 * operation and are ready to return a success/failure code to the buffer 224 * cache layer. 225 */ 226static void raid_end_bio_io(r10bio_t *r10_bio) 227{ 228 struct bio *bio = r10_bio->master_bio; 229 230 bio_endio(bio, bio->bi_size, 231 test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO); 232 free_r10bio(r10_bio); 233} 234 235/* 236 * Update disk head position estimator based on IRQ completion info. 237 */ 238static inline void update_head_pos(int slot, r10bio_t *r10_bio) 239{ 240 conf_t *conf = mddev_to_conf(r10_bio->mddev); 241 242 conf->mirrors[r10_bio->devs[slot].devnum].head_position = 243 r10_bio->devs[slot].addr + (r10_bio->sectors); 244} 245 246static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error) 247{ 248 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 249 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); 250 int slot, dev; 251 conf_t *conf = mddev_to_conf(r10_bio->mddev); 252 253 if (bio->bi_size) 254 return 1; 255 256 slot = r10_bio->read_slot; 257 dev = r10_bio->devs[slot].devnum; 258 /* 259 * this branch is our 'one mirror IO has finished' event handler: 260 */ 261 update_head_pos(slot, r10_bio); 262 263 if (uptodate) { 264 /* 265 * Set R10BIO_Uptodate in our master bio, so that 266 * we will return a good error code to the higher 267 * levels even if IO on some other mirrored buffer fails. 268 * 269 * The 'master' represents the composite IO operation to 270 * user-side. So if something waits for IO, then it will 271 * wait for the 'master' bio. 272 */ 273 set_bit(R10BIO_Uptodate, &r10_bio->state); 274 raid_end_bio_io(r10_bio); 275 } else { 276 /* 277 * oops, read error: 278 */ 279 char b[BDEVNAME_SIZE]; 280 if (printk_ratelimit()) 281 printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n", 282 bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); 283 reschedule_retry(r10_bio); 284 } 285 286 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); 287 return 0; 288} 289 290static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error) 291{ 292 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 293 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); 294 int slot, dev; 295 conf_t *conf = mddev_to_conf(r10_bio->mddev); 296 297 if (bio->bi_size) 298 return 1; 299 300 for (slot = 0; slot < conf->copies; slot++) 301 if (r10_bio->devs[slot].bio == bio) 302 break; 303 dev = r10_bio->devs[slot].devnum; 304 305 /* 306 * this branch is our 'one mirror IO has finished' event handler: 307 */ 308 if (!uptodate) { 309 md_error(r10_bio->mddev, conf->mirrors[dev].rdev); 310 /* an I/O failed, we can't clear the bitmap */ 311 set_bit(R10BIO_Degraded, &r10_bio->state); 312 } else 313 /* 314 * Set R10BIO_Uptodate in our master bio, so that 315 * we will return a good error code for to the higher 316 * levels even if IO on some other mirrored buffer fails. 317 * 318 * The 'master' represents the composite IO operation to 319 * user-side. So if something waits for IO, then it will 320 * wait for the 'master' bio. 321 */ 322 set_bit(R10BIO_Uptodate, &r10_bio->state); 323 324 update_head_pos(slot, r10_bio); 325 326 /* 327 * 328 * Let's see if all mirrored write operations have finished 329 * already. 330 */ 331 if (atomic_dec_and_test(&r10_bio->remaining)) { 332 /* clear the bitmap if all writes complete successfully */ 333 bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector, 334 r10_bio->sectors, 335 !test_bit(R10BIO_Degraded, &r10_bio->state), 336 0); 337 md_write_end(r10_bio->mddev); 338 raid_end_bio_io(r10_bio); 339 } 340 341 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); 342 return 0; 343} 344 345 346/* 347 * RAID10 layout manager 348 * Aswell as the chunksize and raid_disks count, there are two 349 * parameters: near_copies and far_copies. 350 * near_copies * far_copies must be <= raid_disks. 351 * Normally one of these will be 1. 352 * If both are 1, we get raid0. 353 * If near_copies == raid_disks, we get raid1. 354 * 355 * Chunks are layed out in raid0 style with near_copies copies of the 356 * first chunk, followed by near_copies copies of the next chunk and 357 * so on. 358 * If far_copies > 1, then after 1/far_copies of the array has been assigned 359 * as described above, we start again with a device offset of near_copies. 360 * So we effectively have another copy of the whole array further down all 361 * the drives, but with blocks on different drives. 362 * With this layout, and block is never stored twice on the one device. 363 * 364 * raid10_find_phys finds the sector offset of a given virtual sector 365 * on each device that it is on. 366 * 367 * raid10_find_virt does the reverse mapping, from a device and a 368 * sector offset to a virtual address 369 */ 370 371static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) 372{ 373 int n,f; 374 sector_t sector; 375 sector_t chunk; 376 sector_t stripe; 377 int dev; 378 379 int slot = 0; 380 381 /* now calculate first sector/dev */ 382 chunk = r10bio->sector >> conf->chunk_shift; 383 sector = r10bio->sector & conf->chunk_mask; 384 385 chunk *= conf->near_copies; 386 stripe = chunk; 387 dev = sector_div(stripe, conf->raid_disks); 388 if (conf->far_offset) 389 stripe *= conf->far_copies; 390 391 sector += stripe << conf->chunk_shift; 392 393 /* and calculate all the others */ 394 for (n=0; n < conf->near_copies; n++) { 395 int d = dev; 396 sector_t s = sector; 397 r10bio->devs[slot].addr = sector; 398 r10bio->devs[slot].devnum = d; 399 slot++; 400 401 for (f = 1; f < conf->far_copies; f++) { 402 d += conf->near_copies; 403 if (d >= conf->raid_disks) 404 d -= conf->raid_disks; 405 s += conf->stride; 406 r10bio->devs[slot].devnum = d; 407 r10bio->devs[slot].addr = s; 408 slot++; 409 } 410 dev++; 411 if (dev >= conf->raid_disks) { 412 dev = 0; 413 sector += (conf->chunk_mask + 1); 414 } 415 } 416 BUG_ON(slot != conf->copies); 417} 418 419static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) 420{ 421 sector_t offset, chunk, vchunk; 422 423 offset = sector & conf->chunk_mask; 424 if (conf->far_offset) { 425 int fc; 426 chunk = sector >> conf->chunk_shift; 427 fc = sector_div(chunk, conf->far_copies); 428 dev -= fc * conf->near_copies; 429 if (dev < 0) 430 dev += conf->raid_disks; 431 } else { 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 chunk = sector >> conf->chunk_shift; 440 } 441 vchunk = chunk * conf->raid_disks + dev; 442 sector_div(vchunk, conf->near_copies); 443 return (vchunk << conf->chunk_shift) + offset; 444} 445 446/** 447 * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged 448 * @q: request queue 449 * @bio: the buffer head that's been built up so far 450 * @biovec: the request that could be merged to it. 451 * 452 * Return amount of bytes we can accept at this offset 453 * If near_copies == raid_disk, there are no striping issues, 454 * but in that case, the function isn't called at all. 455 */ 456static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio, 457 struct bio_vec *bio_vec) 458{ 459 mddev_t *mddev = q->queuedata; 460 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); 461 int max; 462 unsigned int chunk_sectors = mddev->chunk_size >> 9; 463 unsigned int bio_sectors = bio->bi_size >> 9; 464 465 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; 466 if (max < 0) max = 0; /* bio_add cannot handle a negative return */ 467 if (max <= bio_vec->bv_len && bio_sectors == 0) 468 return bio_vec->bv_len; 469 else 470 return max; 471} 472 473/* 474 * This routine returns the disk from which the requested read should 475 * be done. There is a per-array 'next expected sequential IO' sector 476 * number - if this matches on the next IO then we use the last disk. 477 * There is also a per-disk 'last know head position' sector that is 478 * maintained from IRQ contexts, both the normal and the resync IO 479 * completion handlers update this position correctly. If there is no 480 * perfect sequential match then we pick the disk whose head is closest. 481 * 482 * If there are 2 mirrors in the same 2 devices, performance degrades 483 * because position is mirror, not device based. 484 * 485 * The rdev for the device selected will have nr_pending incremented. 486 */ 487 488static int read_balance(conf_t *conf, r10bio_t *r10_bio) 489{ 490 const unsigned long this_sector = r10_bio->sector; 491 int disk, slot, nslot; 492 const int sectors = r10_bio->sectors; 493 sector_t new_distance, current_distance; 494 mdk_rdev_t *rdev; 495 496 raid10_find_phys(conf, r10_bio); 497 rcu_read_lock(); 498 /* 499 * Check if we can balance. We can balance on the whole 500 * device if no resync is going on (recovery is ok), or below 501 * the resync window. We take the first readable disk when 502 * above the resync window. 503 */ 504 if (conf->mddev->recovery_cp < MaxSector 505 && (this_sector + sectors >= conf->next_resync)) { 506 /* make sure that disk is operational */ 507 slot = 0; 508 disk = r10_bio->devs[slot].devnum; 509 510 while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL || 511 r10_bio->devs[slot].bio == IO_BLOCKED || 512 !test_bit(In_sync, &rdev->flags)) { 513 slot++; 514 if (slot == conf->copies) { 515 slot = 0; 516 disk = -1; 517 break; 518 } 519 disk = r10_bio->devs[slot].devnum; 520 } 521 goto rb_out; 522 } 523 524 525 /* make sure the disk is operational */ 526 slot = 0; 527 disk = r10_bio->devs[slot].devnum; 528 while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL || 529 r10_bio->devs[slot].bio == IO_BLOCKED || 530 !test_bit(In_sync, &rdev->flags)) { 531 slot ++; 532 if (slot == conf->copies) { 533 disk = -1; 534 goto rb_out; 535 } 536 disk = r10_bio->devs[slot].devnum; 537 } 538 539 540 current_distance = abs(r10_bio->devs[slot].addr - 541 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 ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL || 550 r10_bio->devs[nslot].bio == IO_BLOCKED || 551 !test_bit(In_sync, &rdev->flags)) 552 continue; 553 554 /* This optimisation is debatable, and completely destroys 555 * sequential read speed for 'far copies' arrays. So only 556 * keep it for 'near' arrays, and review those later. 557 */ 558 if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) { 559 disk = ndisk; 560 slot = nslot; 561 break; 562 } 563 new_distance = abs(r10_bio->devs[nslot].addr - 564 conf->mirrors[ndisk].head_position); 565 if (new_distance < current_distance) { 566 current_distance = new_distance; 567 disk = ndisk; 568 slot = nslot; 569 } 570 } 571 572rb_out: 573 r10_bio->read_slot = slot; 574/* conf->next_seq_sect = this_sector + sectors;*/ 575 576 if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL) 577 atomic_inc(&conf->mirrors[disk].rdev->nr_pending); 578 else 579 disk = -1; 580 rcu_read_unlock(); 581 582 return disk; 583} 584 585static void unplug_slaves(mddev_t *mddev) 586{ 587 conf_t *conf = mddev_to_conf(mddev); 588 int i; 589 590 rcu_read_lock(); 591 for (i=0; i<mddev->raid_disks; i++) { 592 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 593 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 594 request_queue_t *r_queue = bdev_get_queue(rdev->bdev); 595 596 atomic_inc(&rdev->nr_pending); 597 rcu_read_unlock(); 598 599 if (r_queue->unplug_fn) 600 r_queue->unplug_fn(r_queue); 601 602 rdev_dec_pending(rdev, mddev); 603 rcu_read_lock(); 604 } 605 } 606 rcu_read_unlock(); 607} 608 609static void raid10_unplug(request_queue_t *q) 610{ 611 mddev_t *mddev = q->queuedata; 612 613 unplug_slaves(q->queuedata); 614 md_wakeup_thread(mddev->thread); 615} 616 617static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk, 618 sector_t *error_sector) 619{ 620 mddev_t *mddev = q->queuedata; 621 conf_t *conf = mddev_to_conf(mddev); 622 int i, ret = 0; 623 624 rcu_read_lock(); 625 for (i=0; i<mddev->raid_disks && ret == 0; i++) { 626 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 627 if (rdev && !test_bit(Faulty, &rdev->flags)) { 628 struct block_device *bdev = rdev->bdev; 629 request_queue_t *r_queue = bdev_get_queue(bdev); 630 631 if (!r_queue->issue_flush_fn) 632 ret = -EOPNOTSUPP; 633 else { 634 atomic_inc(&rdev->nr_pending); 635 rcu_read_unlock(); 636 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, 637 error_sector); 638 rdev_dec_pending(rdev, mddev); 639 rcu_read_lock(); 640 } 641 } 642 } 643 rcu_read_unlock(); 644 return ret; 645} 646 647static int raid10_congested(void *data, int bits) 648{ 649 mddev_t *mddev = data; 650 conf_t *conf = mddev_to_conf(mddev); 651 int i, ret = 0; 652 653 rcu_read_lock(); 654 for (i = 0; i < mddev->raid_disks && ret == 0; i++) { 655 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 656 if (rdev && !test_bit(Faulty, &rdev->flags)) { 657 request_queue_t *q = bdev_get_queue(rdev->bdev); 658 659 ret |= bdi_congested(&q->backing_dev_info, bits); 660 } 661 } 662 rcu_read_unlock(); 663 return ret; 664} 665 666 667/* Barriers.... 668 * Sometimes we need to suspend IO while we do something else, 669 * either some resync/recovery, or reconfigure the array. 670 * To do this we raise a 'barrier'. 671 * The 'barrier' is a counter that can be raised multiple times 672 * to count how many activities are happening which preclude 673 * normal IO. 674 * We can only raise the barrier if there is no pending IO. 675 * i.e. if nr_pending == 0. 676 * We choose only to raise the barrier if no-one is waiting for the 677 * barrier to go down. This means that as soon as an IO request 678 * is ready, no other operations which require a barrier will start 679 * until the IO request has had a chance. 680 * 681 * So: regular IO calls 'wait_barrier'. When that returns there 682 * is no backgroup IO happening, It must arrange to call 683 * allow_barrier when it has finished its IO. 684 * backgroup IO calls must call raise_barrier. Once that returns 685 * there is no normal IO happeing. It must arrange to call 686 * lower_barrier when the particular background IO completes. 687 */ 688#define RESYNC_DEPTH 32 689 690static void raise_barrier(conf_t *conf, int force) 691{ 692 BUG_ON(force && !conf->barrier); 693 spin_lock_irq(&conf->resync_lock); 694 695 /* Wait until no block IO is waiting (unless 'force') */ 696 wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, 697 conf->resync_lock, 698 raid10_unplug(conf->mddev->queue)); 699 700 /* block any new IO from starting */ 701 conf->barrier++; 702 703 /* No wait for all pending IO to complete */ 704 wait_event_lock_irq(conf->wait_barrier, 705 !conf->nr_pending && conf->barrier < RESYNC_DEPTH, 706 conf->resync_lock, 707 raid10_unplug(conf->mddev->queue)); 708 709 spin_unlock_irq(&conf->resync_lock); 710} 711 712static void lower_barrier(conf_t *conf) 713{ 714 unsigned long flags; 715 spin_lock_irqsave(&conf->resync_lock, flags); 716 conf->barrier--; 717 spin_unlock_irqrestore(&conf->resync_lock, flags); 718 wake_up(&conf->wait_barrier); 719} 720 721static void wait_barrier(conf_t *conf) 722{ 723 spin_lock_irq(&conf->resync_lock); 724 if (conf->barrier) { 725 conf->nr_waiting++; 726 wait_event_lock_irq(conf->wait_barrier, !conf->barrier, 727 conf->resync_lock, 728 raid10_unplug(conf->mddev->queue)); 729 conf->nr_waiting--; 730 } 731 conf->nr_pending++; 732 spin_unlock_irq(&conf->resync_lock); 733} 734 735static void allow_barrier(conf_t *conf) 736{ 737 unsigned long flags; 738 spin_lock_irqsave(&conf->resync_lock, flags); 739 conf->nr_pending--; 740 spin_unlock_irqrestore(&conf->resync_lock, flags); 741 wake_up(&conf->wait_barrier); 742} 743 744static void freeze_array(conf_t *conf) 745{ 746 /* stop syncio and normal IO and wait for everything to 747 * go quiet. 748 * We increment barrier and nr_waiting, and then 749 * wait until barrier+nr_pending match nr_queued+2 750 */ 751 spin_lock_irq(&conf->resync_lock); 752 conf->barrier++; 753 conf->nr_waiting++; 754 wait_event_lock_irq(conf->wait_barrier, 755 conf->barrier+conf->nr_pending == conf->nr_queued+2, 756 conf->resync_lock, 757 raid10_unplug(conf->mddev->queue)); 758 spin_unlock_irq(&conf->resync_lock); 759} 760 761static void unfreeze_array(conf_t *conf) 762{ 763 /* reverse the effect of the freeze */ 764 spin_lock_irq(&conf->resync_lock); 765 conf->barrier--; 766 conf->nr_waiting--; 767 wake_up(&conf->wait_barrier); 768 spin_unlock_irq(&conf->resync_lock); 769} 770 771static int make_request(request_queue_t *q, struct bio * bio) 772{ 773 mddev_t *mddev = q->queuedata; 774 conf_t *conf = mddev_to_conf(mddev); 775 mirror_info_t *mirror; 776 r10bio_t *r10_bio; 777 struct bio *read_bio; 778 int i; 779 int chunk_sects = conf->chunk_mask + 1; 780 const int rw = bio_data_dir(bio); 781 const int do_sync = bio_sync(bio); 782 struct bio_list bl; 783 unsigned long flags; 784 785 if (unlikely(bio_barrier(bio))) { 786 bio_endio(bio, bio->bi_size, -EOPNOTSUPP); 787 return 0; 788 } 789 790 /* If this request crosses a chunk boundary, we need to 791 * split it. This will only happen for 1 PAGE (or less) requests. 792 */ 793 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) 794 > chunk_sects && 795 conf->near_copies < conf->raid_disks)) { 796 struct bio_pair *bp; 797 /* Sanity check -- queue functions should prevent this happening */ 798 if (bio->bi_vcnt != 1 || 799 bio->bi_idx != 0) 800 goto bad_map; 801 /* This is a one page bio that upper layers 802 * refuse to split for us, so we need to split it. 803 */ 804 bp = bio_split(bio, bio_split_pool, 805 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); 806 if (make_request(q, &bp->bio1)) 807 generic_make_request(&bp->bio1); 808 if (make_request(q, &bp->bio2)) 809 generic_make_request(&bp->bio2); 810 811 bio_pair_release(bp); 812 return 0; 813 bad_map: 814 printk("raid10_make_request bug: can't convert block across chunks" 815 " or bigger than %dk %llu %d\n", chunk_sects/2, 816 (unsigned long long)bio->bi_sector, bio->bi_size >> 10); 817 818 bio_io_error(bio, bio->bi_size); 819 return 0; 820 } 821 822 md_write_start(mddev, bio); 823 824 /* 825 * Register the new request and wait if the reconstruction 826 * thread has put up a bar for new requests. 827 * Continue immediately if no resync is active currently. 828 */ 829 wait_barrier(conf); 830 831 disk_stat_inc(mddev->gendisk, ios[rw]); 832 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); 833 834 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); 835 836 r10_bio->master_bio = bio; 837 r10_bio->sectors = bio->bi_size >> 9; 838 839 r10_bio->mddev = mddev; 840 r10_bio->sector = bio->bi_sector; 841 r10_bio->state = 0; 842 843 if (rw == READ) { 844 /* 845 * read balancing logic: 846 */ 847 int disk = read_balance(conf, r10_bio); 848 int slot = r10_bio->read_slot; 849 if (disk < 0) { 850 raid_end_bio_io(r10_bio); 851 return 0; 852 } 853 mirror = conf->mirrors + disk; 854 855 read_bio = bio_clone(bio, GFP_NOIO); 856 857 r10_bio->devs[slot].bio = read_bio; 858 859 read_bio->bi_sector = r10_bio->devs[slot].addr + 860 mirror->rdev->data_offset; 861 read_bio->bi_bdev = mirror->rdev->bdev; 862 read_bio->bi_end_io = raid10_end_read_request; 863 read_bio->bi_rw = READ | do_sync; 864 read_bio->bi_private = r10_bio; 865 866 generic_make_request(read_bio); 867 return 0; 868 } 869 870 /* 871 * WRITE: 872 */ 873 /* first select target devices under spinlock and 874 * inc refcount on their rdev. Record them by setting 875 * bios[x] to bio 876 */ 877 raid10_find_phys(conf, r10_bio); 878 rcu_read_lock(); 879 for (i = 0; i < conf->copies; i++) { 880 int d = r10_bio->devs[i].devnum; 881 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev); 882 if (rdev && 883 !test_bit(Faulty, &rdev->flags)) { 884 atomic_inc(&rdev->nr_pending); 885 r10_bio->devs[i].bio = bio; 886 } else { 887 r10_bio->devs[i].bio = NULL; 888 set_bit(R10BIO_Degraded, &r10_bio->state); 889 } 890 } 891 rcu_read_unlock(); 892 893 atomic_set(&r10_bio->remaining, 0); 894 895 bio_list_init(&bl); 896 for (i = 0; i < conf->copies; i++) { 897 struct bio *mbio; 898 int d = r10_bio->devs[i].devnum; 899 if (!r10_bio->devs[i].bio) 900 continue; 901 902 mbio = bio_clone(bio, GFP_NOIO); 903 r10_bio->devs[i].bio = mbio; 904 905 mbio->bi_sector = r10_bio->devs[i].addr+ 906 conf->mirrors[d].rdev->data_offset; 907 mbio->bi_bdev = conf->mirrors[d].rdev->bdev; 908 mbio->bi_end_io = raid10_end_write_request; 909 mbio->bi_rw = WRITE | do_sync; 910 mbio->bi_private = r10_bio; 911 912 atomic_inc(&r10_bio->remaining); 913 bio_list_add(&bl, mbio); 914 } 915 916 bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0); 917 spin_lock_irqsave(&conf->device_lock, flags); 918 bio_list_merge(&conf->pending_bio_list, &bl); 919 blk_plug_device(mddev->queue); 920 spin_unlock_irqrestore(&conf->device_lock, flags); 921 922 if (do_sync) 923 md_wakeup_thread(mddev->thread); 924 925 return 0; 926} 927 928static void status(struct seq_file *seq, mddev_t *mddev) 929{ 930 conf_t *conf = mddev_to_conf(mddev); 931 int i; 932 933 if (conf->near_copies < conf->raid_disks) 934 seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); 935 if (conf->near_copies > 1) 936 seq_printf(seq, " %d near-copies", conf->near_copies); 937 if (conf->far_copies > 1) { 938 if (conf->far_offset) 939 seq_printf(seq, " %d offset-copies", conf->far_copies); 940 else 941 seq_printf(seq, " %d far-copies", conf->far_copies); 942 } 943 seq_printf(seq, " [%d/%d] [", conf->raid_disks, 944 conf->raid_disks - mddev->degraded); 945 for (i = 0; i < conf->raid_disks; i++) 946 seq_printf(seq, "%s", 947 conf->mirrors[i].rdev && 948 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_"); 949 seq_printf(seq, "]"); 950} 951 952static void error(mddev_t *mddev, mdk_rdev_t *rdev) 953{ 954 char b[BDEVNAME_SIZE]; 955 conf_t *conf = mddev_to_conf(mddev); 956 957 /* 958 * If it is not operational, then we have already marked it as dead 959 * else if it is the last working disks, ignore the error, let the 960 * next level up know. 961 * else mark the drive as failed 962 */ 963 if (test_bit(In_sync, &rdev->flags) 964 && conf->raid_disks-mddev->degraded == 1) 965 /* 966 * Don't fail the drive, just return an IO error. 967 * The test should really be more sophisticated than 968 * "working_disks == 1", but it isn't critical, and 969 * can wait until we do more sophisticated "is the drive 970 * really dead" tests... 971 */ 972 return; 973 if (test_and_clear_bit(In_sync, &rdev->flags)) { 974 unsigned long flags; 975 spin_lock_irqsave(&conf->device_lock, flags); 976 mddev->degraded++; 977 spin_unlock_irqrestore(&conf->device_lock, flags); 978 /* 979 * if recovery is running, make sure it aborts. 980 */ 981 set_bit(MD_RECOVERY_ERR, &mddev->recovery); 982 } 983 set_bit(Faulty, &rdev->flags); 984 set_bit(MD_CHANGE_DEVS, &mddev->flags); 985 printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n" 986 " Operation continuing on %d devices\n", 987 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); 988} 989 990static void print_conf(conf_t *conf) 991{ 992 int i; 993 mirror_info_t *tmp; 994 995 printk("RAID10 conf printout:\n"); 996 if (!conf) { 997 printk("(!conf)\n"); 998 return; 999 } 1000 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, 1001 conf->raid_disks); 1002 1003 for (i = 0; i < conf->raid_disks; i++) { 1004 char b[BDEVNAME_SIZE]; 1005 tmp = conf->mirrors + i; 1006 if (tmp->rdev) 1007 printk(" disk %d, wo:%d, o:%d, dev:%s\n", 1008 i, !test_bit(In_sync, &tmp->rdev->flags), 1009 !test_bit(Faulty, &tmp->rdev->flags), 1010 bdevname(tmp->rdev->bdev,b)); 1011 } 1012} 1013 1014static void close_sync(conf_t *conf) 1015{ 1016 wait_barrier(conf); 1017 allow_barrier(conf); 1018 1019 mempool_destroy(conf->r10buf_pool); 1020 conf->r10buf_pool = NULL; 1021} 1022 1023/* check if there are enough drives for 1024 * every block to appear on atleast one 1025 */ 1026static int enough(conf_t *conf) 1027{ 1028 int first = 0; 1029 1030 do { 1031 int n = conf->copies; 1032 int cnt = 0; 1033 while (n--) { 1034 if (conf->mirrors[first].rdev) 1035 cnt++; 1036 first = (first+1) % conf->raid_disks; 1037 } 1038 if (cnt == 0) 1039 return 0; 1040 } while (first != 0); 1041 return 1; 1042} 1043 1044static int raid10_spare_active(mddev_t *mddev) 1045{ 1046 int i; 1047 conf_t *conf = mddev->private; 1048 mirror_info_t *tmp; 1049 1050 /* 1051 * Find all non-in_sync disks within the RAID10 configuration 1052 * and mark them in_sync 1053 */ 1054 for (i = 0; i < conf->raid_disks; i++) { 1055 tmp = conf->mirrors + i; 1056 if (tmp->rdev 1057 && !test_bit(Faulty, &tmp->rdev->flags) 1058 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 1059 unsigned long flags; 1060 spin_lock_irqsave(&conf->device_lock, flags); 1061 mddev->degraded--; 1062 spin_unlock_irqrestore(&conf->device_lock, flags); 1063 } 1064 } 1065 1066 print_conf(conf); 1067 return 0; 1068} 1069 1070 1071static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 1072{ 1073 conf_t *conf = mddev->private; 1074 int found = 0; 1075 int mirror; 1076 mirror_info_t *p; 1077 1078 if (mddev->recovery_cp < MaxSector) 1079 /* only hot-add to in-sync arrays, as recovery is 1080 * very different from resync 1081 */ 1082 return 0; 1083 if (!enough(conf)) 1084 return 0; 1085 1086 if (rdev->saved_raid_disk >= 0 && 1087 conf->mirrors[rdev->saved_raid_disk].rdev == NULL) 1088 mirror = rdev->saved_raid_disk; 1089 else 1090 mirror = 0; 1091 for ( ; mirror < mddev->raid_disks; mirror++) 1092 if ( !(p=conf->mirrors+mirror)->rdev) { 1093 1094 blk_queue_stack_limits(mddev->queue, 1095 rdev->bdev->bd_disk->queue); 1096 /* as we don't honour merge_bvec_fn, we must never risk 1097 * violating it, so limit ->max_sector to one PAGE, as 1098 * a one page request is never in violation. 1099 */ 1100 if (rdev->bdev->bd_disk->queue->merge_bvec_fn && 1101 mddev->queue->max_sectors > (PAGE_SIZE>>9)) 1102 mddev->queue->max_sectors = (PAGE_SIZE>>9); 1103 1104 p->head_position = 0; 1105 rdev->raid_disk = mirror; 1106 found = 1; 1107 if (rdev->saved_raid_disk != mirror) 1108 conf->fullsync = 1; 1109 rcu_assign_pointer(p->rdev, rdev); 1110 break; 1111 } 1112 1113 print_conf(conf); 1114 return found; 1115} 1116 1117static int raid10_remove_disk(mddev_t *mddev, int number) 1118{ 1119 conf_t *conf = mddev->private; 1120 int err = 0; 1121 mdk_rdev_t *rdev; 1122 mirror_info_t *p = conf->mirrors+ number; 1123 1124 print_conf(conf); 1125 rdev = p->rdev; 1126 if (rdev) { 1127 if (test_bit(In_sync, &rdev->flags) || 1128 atomic_read(&rdev->nr_pending)) { 1129 err = -EBUSY; 1130 goto abort; 1131 } 1132 p->rdev = NULL; 1133 synchronize_rcu(); 1134 if (atomic_read(&rdev->nr_pending)) { 1135 /* lost the race, try later */ 1136 err = -EBUSY; 1137 p->rdev = rdev; 1138 } 1139 } 1140abort: 1141 1142 print_conf(conf); 1143 return err; 1144} 1145 1146 1147static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error) 1148{ 1149 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); 1150 conf_t *conf = mddev_to_conf(r10_bio->mddev); 1151 int i,d; 1152 1153 if (bio->bi_size) 1154 return 1; 1155 1156 for (i=0; i<conf->copies; i++) 1157 if (r10_bio->devs[i].bio == bio) 1158 break; 1159 BUG_ON(i == conf->copies); 1160 update_head_pos(i, r10_bio); 1161 d = r10_bio->devs[i].devnum; 1162 1163 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 1164 set_bit(R10BIO_Uptodate, &r10_bio->state); 1165 else { 1166 atomic_add(r10_bio->sectors, 1167 &conf->mirrors[d].rdev->corrected_errors); 1168 if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) 1169 md_error(r10_bio->mddev, 1170 conf->mirrors[d].rdev); 1171 } 1172 1173 /* for reconstruct, we always reschedule after a read. 1174 * for resync, only after all reads 1175 */ 1176 if (test_bit(R10BIO_IsRecover, &r10_bio->state) || 1177 atomic_dec_and_test(&r10_bio->remaining)) { 1178 /* we have read all the blocks, 1179 * do the comparison in process context in raid10d 1180 */ 1181 reschedule_retry(r10_bio); 1182 } 1183 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); 1184 return 0; 1185} 1186 1187static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error) 1188{ 1189 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 1190 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); 1191 mddev_t *mddev = r10_bio->mddev; 1192 conf_t *conf = mddev_to_conf(mddev); 1193 int i,d; 1194 1195 if (bio->bi_size) 1196 return 1; 1197 1198 for (i = 0; i < conf->copies; i++) 1199 if (r10_bio->devs[i].bio == bio) 1200 break; 1201 d = r10_bio->devs[i].devnum; 1202 1203 if (!uptodate) 1204 md_error(mddev, conf->mirrors[d].rdev); 1205 update_head_pos(i, r10_bio); 1206 1207 while (atomic_dec_and_test(&r10_bio->remaining)) { 1208 if (r10_bio->master_bio == NULL) { 1209 /* the primary of several recovery bios */ 1210 md_done_sync(mddev, r10_bio->sectors, 1); 1211 put_buf(r10_bio); 1212 break; 1213 } else { 1214 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; 1215 put_buf(r10_bio); 1216 r10_bio = r10_bio2; 1217 } 1218 } 1219 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 1220 return 0; 1221} 1222 1223/* 1224 * Note: sync and recover and handled very differently for raid10 1225 * This code is for resync. 1226 * For resync, we read through virtual addresses and read all blocks. 1227 * If there is any error, we schedule a write. The lowest numbered 1228 * drive is authoritative. 1229 * However requests come for physical address, so we need to map. 1230 * For every physical address there are raid_disks/copies virtual addresses, 1231 * which is always are least one, but is not necessarly an integer. 1232 * This means that a physical address can span multiple chunks, so we may 1233 * have to submit multiple io requests for a single sync request. 1234 */ 1235/* 1236 * We check if all blocks are in-sync and only write to blocks that 1237 * aren't in sync 1238 */ 1239static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) 1240{ 1241 conf_t *conf = mddev_to_conf(mddev); 1242 int i, first; 1243 struct bio *tbio, *fbio; 1244 1245 atomic_set(&r10_bio->remaining, 1); 1246 1247 /* find the first device with a block */ 1248 for (i=0; i<conf->copies; i++) 1249 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) 1250 break; 1251 1252 if (i == conf->copies) 1253 goto done; 1254 1255 first = i; 1256 fbio = r10_bio->devs[i].bio; 1257 1258 /* now find blocks with errors */ 1259 for (i=0 ; i < conf->copies ; i++) { 1260 int j, d; 1261 int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); 1262 1263 tbio = r10_bio->devs[i].bio; 1264 1265 if (tbio->bi_end_io != end_sync_read) 1266 continue; 1267 if (i == first) 1268 continue; 1269 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) { 1270 /* We know that the bi_io_vec layout is the same for 1271 * both 'first' and 'i', so we just compare them. 1272 * All vec entries are PAGE_SIZE; 1273 */ 1274 for (j = 0; j < vcnt; j++) 1275 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), 1276 page_address(tbio->bi_io_vec[j].bv_page), 1277 PAGE_SIZE)) 1278 break; 1279 if (j == vcnt) 1280 continue; 1281 mddev->resync_mismatches += r10_bio->sectors; 1282 } 1283 if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) 1284 /* Don't fix anything. */ 1285 continue; 1286 /* Ok, we need to write this bio 1287 * First we need to fixup bv_offset, bv_len and 1288 * bi_vecs, as the read request might have corrupted these 1289 */ 1290 tbio->bi_vcnt = vcnt; 1291 tbio->bi_size = r10_bio->sectors << 9; 1292 tbio->bi_idx = 0; 1293 tbio->bi_phys_segments = 0; 1294 tbio->bi_hw_segments = 0; 1295 tbio->bi_hw_front_size = 0; 1296 tbio->bi_hw_back_size = 0; 1297 tbio->bi_flags &= ~(BIO_POOL_MASK - 1); 1298 tbio->bi_flags |= 1 << BIO_UPTODATE; 1299 tbio->bi_next = NULL; 1300 tbio->bi_rw = WRITE; 1301 tbio->bi_private = r10_bio; 1302 tbio->bi_sector = r10_bio->devs[i].addr; 1303 1304 for (j=0; j < vcnt ; j++) { 1305 tbio->bi_io_vec[j].bv_offset = 0; 1306 tbio->bi_io_vec[j].bv_len = PAGE_SIZE; 1307 1308 memcpy(page_address(tbio->bi_io_vec[j].bv_page), 1309 page_address(fbio->bi_io_vec[j].bv_page), 1310 PAGE_SIZE); 1311 } 1312 tbio->bi_end_io = end_sync_write; 1313 1314 d = r10_bio->devs[i].devnum; 1315 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1316 atomic_inc(&r10_bio->remaining); 1317 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); 1318 1319 tbio->bi_sector += conf->mirrors[d].rdev->data_offset; 1320 tbio->bi_bdev = conf->mirrors[d].rdev->bdev; 1321 generic_make_request(tbio); 1322 } 1323 1324done: 1325 if (atomic_dec_and_test(&r10_bio->remaining)) { 1326 md_done_sync(mddev, r10_bio->sectors, 1); 1327 put_buf(r10_bio); 1328 } 1329} 1330 1331/* 1332 * Now for the recovery code. 1333 * Recovery happens across physical sectors. 1334 * We recover all non-is_sync drives by finding the virtual address of 1335 * each, and then choose a working drive that also has that virt address. 1336 * There is a separate r10_bio for each non-in_sync drive. 1337 * Only the first two slots are in use. The first for reading, 1338 * The second for writing. 1339 * 1340 */ 1341 1342static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) 1343{ 1344 conf_t *conf = mddev_to_conf(mddev); 1345 int i, d; 1346 struct bio *bio, *wbio; 1347 1348 1349 /* move the pages across to the second bio 1350 * and submit the write request 1351 */ 1352 bio = r10_bio->devs[0].bio; 1353 wbio = r10_bio->devs[1].bio; 1354 for (i=0; i < wbio->bi_vcnt; i++) { 1355 struct page *p = bio->bi_io_vec[i].bv_page; 1356 bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; 1357 wbio->bi_io_vec[i].bv_page = p; 1358 } 1359 d = r10_bio->devs[1].devnum; 1360 1361 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1362 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); 1363 if (test_bit(R10BIO_Uptodate, &r10_bio->state)) 1364 generic_make_request(wbio); 1365 else 1366 bio_endio(wbio, wbio->bi_size, -EIO); 1367} 1368 1369 1370/* 1371 * This is a kernel thread which: 1372 * 1373 * 1. Retries failed read operations on working mirrors. 1374 * 2. Updates the raid superblock when problems encounter. 1375 * 3. Performs writes following reads for array synchronising. 1376 */ 1377 1378static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) 1379{ 1380 int sect = 0; /* Offset from r10_bio->sector */ 1381 int sectors = r10_bio->sectors; 1382 mdk_rdev_t*rdev; 1383 while(sectors) { 1384 int s = sectors; 1385 int sl = r10_bio->read_slot; 1386 int success = 0; 1387 int start; 1388 1389 if (s > (PAGE_SIZE>>9)) 1390 s = PAGE_SIZE >> 9; 1391 1392 rcu_read_lock(); 1393 do { 1394 int d = r10_bio->devs[sl].devnum; 1395 rdev = rcu_dereference(conf->mirrors[d].rdev); 1396 if (rdev && 1397 test_bit(In_sync, &rdev->flags)) { 1398 atomic_inc(&rdev->nr_pending); 1399 rcu_read_unlock(); 1400 success = sync_page_io(rdev->bdev, 1401 r10_bio->devs[sl].addr + 1402 sect + rdev->data_offset, 1403 s<<9, 1404 conf->tmppage, READ); 1405 rdev_dec_pending(rdev, mddev); 1406 rcu_read_lock(); 1407 if (success) 1408 break; 1409 } 1410 sl++; 1411 if (sl == conf->copies) 1412 sl = 0; 1413 } while (!success && sl != r10_bio->read_slot); 1414 rcu_read_unlock(); 1415 1416 if (!success) { 1417 /* Cannot read from anywhere -- bye bye array */ 1418 int dn = r10_bio->devs[r10_bio->read_slot].devnum; 1419 md_error(mddev, conf->mirrors[dn].rdev); 1420 break; 1421 } 1422 1423 start = sl; 1424 /* write it back and re-read */ 1425 rcu_read_lock(); 1426 while (sl != r10_bio->read_slot) { 1427 int d; 1428 if (sl==0) 1429 sl = conf->copies; 1430 sl--; 1431 d = r10_bio->devs[sl].devnum; 1432 rdev = rcu_dereference(conf->mirrors[d].rdev); 1433 if (rdev && 1434 test_bit(In_sync, &rdev->flags)) { 1435 atomic_inc(&rdev->nr_pending); 1436 rcu_read_unlock(); 1437 atomic_add(s, &rdev->corrected_errors); 1438 if (sync_page_io(rdev->bdev, 1439 r10_bio->devs[sl].addr + 1440 sect + rdev->data_offset, 1441 s<<9, conf->tmppage, WRITE) 1442 == 0) 1443 /* Well, this device is dead */ 1444 md_error(mddev, rdev); 1445 rdev_dec_pending(rdev, mddev); 1446 rcu_read_lock(); 1447 } 1448 } 1449 sl = start; 1450 while (sl != r10_bio->read_slot) { 1451 int d; 1452 if (sl==0) 1453 sl = conf->copies; 1454 sl--; 1455 d = r10_bio->devs[sl].devnum; 1456 rdev = rcu_dereference(conf->mirrors[d].rdev); 1457 if (rdev && 1458 test_bit(In_sync, &rdev->flags)) { 1459 char b[BDEVNAME_SIZE]; 1460 atomic_inc(&rdev->nr_pending); 1461 rcu_read_unlock(); 1462 if (sync_page_io(rdev->bdev, 1463 r10_bio->devs[sl].addr + 1464 sect + rdev->data_offset, 1465 s<<9, conf->tmppage, READ) == 0) 1466 /* Well, this device is dead */ 1467 md_error(mddev, rdev); 1468 else 1469 printk(KERN_INFO 1470 "raid10:%s: read error corrected" 1471 " (%d sectors at %llu on %s)\n", 1472 mdname(mddev), s, 1473 (unsigned long long)(sect+ 1474 rdev->data_offset), 1475 bdevname(rdev->bdev, b)); 1476 1477 rdev_dec_pending(rdev, mddev); 1478 rcu_read_lock(); 1479 } 1480 } 1481 rcu_read_unlock(); 1482 1483 sectors -= s; 1484 sect += s; 1485 } 1486} 1487 1488static void raid10d(mddev_t *mddev) 1489{ 1490 r10bio_t *r10_bio; 1491 struct bio *bio; 1492 unsigned long flags; 1493 conf_t *conf = mddev_to_conf(mddev); 1494 struct list_head *head = &conf->retry_list; 1495 int unplug=0; 1496 mdk_rdev_t *rdev; 1497 1498 md_check_recovery(mddev); 1499 1500 for (;;) { 1501 char b[BDEVNAME_SIZE]; 1502 spin_lock_irqsave(&conf->device_lock, flags); 1503 1504 if (conf->pending_bio_list.head) { 1505 bio = bio_list_get(&conf->pending_bio_list); 1506 blk_remove_plug(mddev->queue); 1507 spin_unlock_irqrestore(&conf->device_lock, flags); 1508 /* flush any pending bitmap writes to disk before proceeding w/ I/O */ 1509 if (bitmap_unplug(mddev->bitmap) != 0) 1510 printk("%s: bitmap file write failed!\n", mdname(mddev)); 1511 1512 while (bio) { /* submit pending writes */ 1513 struct bio *next = bio->bi_next; 1514 bio->bi_next = NULL; 1515 generic_make_request(bio); 1516 bio = next; 1517 } 1518 unplug = 1; 1519 1520 continue; 1521 } 1522 1523 if (list_empty(head)) 1524 break; 1525 r10_bio = list_entry(head->prev, r10bio_t, retry_list); 1526 list_del(head->prev); 1527 conf->nr_queued--; 1528 spin_unlock_irqrestore(&conf->device_lock, flags); 1529 1530 mddev = r10_bio->mddev; 1531 conf = mddev_to_conf(mddev); 1532 if (test_bit(R10BIO_IsSync, &r10_bio->state)) { 1533 sync_request_write(mddev, r10_bio); 1534 unplug = 1; 1535 } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { 1536 recovery_request_write(mddev, r10_bio); 1537 unplug = 1; 1538 } else { 1539 int mirror; 1540 /* we got a read error. Maybe the drive is bad. Maybe just 1541 * the block and we can fix it. 1542 * We freeze all other IO, and try reading the block from 1543 * other devices. When we find one, we re-write 1544 * and check it that fixes the read error. 1545 * This is all done synchronously while the array is 1546 * frozen. 1547 */ 1548 if (mddev->ro == 0) { 1549 freeze_array(conf); 1550 fix_read_error(conf, mddev, r10_bio); 1551 unfreeze_array(conf); 1552 } 1553 1554 bio = r10_bio->devs[r10_bio->read_slot].bio; 1555 r10_bio->devs[r10_bio->read_slot].bio = 1556 mddev->ro ? IO_BLOCKED : NULL; 1557 bio_put(bio); 1558 mirror = read_balance(conf, r10_bio); 1559 if (mirror == -1) { 1560 printk(KERN_ALERT "raid10: %s: unrecoverable I/O" 1561 " read error for block %llu\n", 1562 bdevname(bio->bi_bdev,b), 1563 (unsigned long long)r10_bio->sector); 1564 raid_end_bio_io(r10_bio); 1565 } else { 1566 const int do_sync = bio_sync(r10_bio->master_bio); 1567 rdev = conf->mirrors[mirror].rdev; 1568 if (printk_ratelimit()) 1569 printk(KERN_ERR "raid10: %s: redirecting sector %llu to" 1570 " another mirror\n", 1571 bdevname(rdev->bdev,b), 1572 (unsigned long long)r10_bio->sector); 1573 bio = bio_clone(r10_bio->master_bio, GFP_NOIO); 1574 r10_bio->devs[r10_bio->read_slot].bio = bio; 1575 bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr 1576 + rdev->data_offset; 1577 bio->bi_bdev = rdev->bdev; 1578 bio->bi_rw = READ | do_sync; 1579 bio->bi_private = r10_bio; 1580 bio->bi_end_io = raid10_end_read_request; 1581 unplug = 1; 1582 generic_make_request(bio); 1583 } 1584 } 1585 } 1586 spin_unlock_irqrestore(&conf->device_lock, flags); 1587 if (unplug) 1588 unplug_slaves(mddev); 1589} 1590 1591 1592static int init_resync(conf_t *conf) 1593{ 1594 int buffs; 1595 1596 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; 1597 BUG_ON(conf->r10buf_pool); 1598 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); 1599 if (!conf->r10buf_pool) 1600 return -ENOMEM; 1601 conf->next_resync = 0; 1602 return 0; 1603} 1604 1605/* 1606 * perform a "sync" on one "block" 1607 * 1608 * We need to make sure that no normal I/O request - particularly write 1609 * requests - conflict with active sync requests. 1610 * 1611 * This is achieved by tracking pending requests and a 'barrier' concept 1612 * that can be installed to exclude normal IO requests. 1613 * 1614 * Resync and recovery are handled very differently. 1615 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. 1616 * 1617 * For resync, we iterate over virtual addresses, read all copies, 1618 * and update if there are differences. If only one copy is live, 1619 * skip it. 1620 * For recovery, we iterate over physical addresses, read a good 1621 * value for each non-in_sync drive, and over-write. 1622 * 1623 * So, for recovery we may have several outstanding complex requests for a 1624 * given address, one for each out-of-sync device. We model this by allocating 1625 * a number of r10_bio structures, one for each out-of-sync device. 1626 * As we setup these structures, we collect all bio's together into a list 1627 * which we then process collectively to add pages, and then process again 1628 * to pass to generic_make_request. 1629 * 1630 * The r10_bio structures are linked using a borrowed master_bio pointer. 1631 * This link is counted in ->remaining. When the r10_bio that points to NULL 1632 * has its remaining count decremented to 0, the whole complex operation 1633 * is complete. 1634 * 1635 */ 1636 1637static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 1638{ 1639 conf_t *conf = mddev_to_conf(mddev); 1640 r10bio_t *r10_bio; 1641 struct bio *biolist = NULL, *bio; 1642 sector_t max_sector, nr_sectors; 1643 int disk; 1644 int i; 1645 int max_sync; 1646 int sync_blocks; 1647 1648 sector_t sectors_skipped = 0; 1649 int chunks_skipped = 0; 1650 1651 if (!conf->r10buf_pool) 1652 if (init_resync(conf)) 1653 return 0; 1654 1655 skipped: 1656 max_sector = mddev->size << 1; 1657 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) 1658 max_sector = mddev->resync_max_sectors; 1659 if (sector_nr >= max_sector) { 1660 /* If we aborted, we need to abort the 1661 * sync on the 'current' bitmap chucks (there can 1662 * be several when recovering multiple devices). 1663 * as we may have started syncing it but not finished. 1664 * We can find the current address in 1665 * mddev->curr_resync, but for recovery, 1666 * we need to convert that to several 1667 * virtual addresses. 1668 */ 1669 if (mddev->curr_resync < max_sector) { /* aborted */ 1670 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) 1671 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 1672 &sync_blocks, 1); 1673 else for (i=0; i<conf->raid_disks; i++) { 1674 sector_t sect = 1675 raid10_find_virt(conf, mddev->curr_resync, i); 1676 bitmap_end_sync(mddev->bitmap, sect, 1677 &sync_blocks, 1); 1678 } 1679 } else /* completed sync */ 1680 conf->fullsync = 0; 1681 1682 bitmap_close_sync(mddev->bitmap); 1683 close_sync(conf); 1684 *skipped = 1; 1685 return sectors_skipped; 1686 } 1687 if (chunks_skipped >= conf->raid_disks) { 1688 /* if there has been nothing to do on any drive, 1689 * then there is nothing to do at all.. 1690 */ 1691 *skipped = 1; 1692 return (max_sector - sector_nr) + sectors_skipped; 1693 } 1694 1695 /* make sure whole request will fit in a chunk - if chunks 1696 * are meaningful 1697 */ 1698 if (conf->near_copies < conf->raid_disks && 1699 max_sector > (sector_nr | conf->chunk_mask)) 1700 max_sector = (sector_nr | conf->chunk_mask) + 1; 1701 /* 1702 * If there is non-resync activity waiting for us then 1703 * put in a delay to throttle resync. 1704 */ 1705 if (!go_faster && conf->nr_waiting) 1706 msleep_interruptible(1000); 1707 1708 /* Again, very different code for resync and recovery. 1709 * Both must result in an r10bio with a list of bios that 1710 * have bi_end_io, bi_sector, bi_bdev set, 1711 * and bi_private set to the r10bio. 1712 * For recovery, we may actually create several r10bios 1713 * with 2 bios in each, that correspond to the bios in the main one. 1714 * In this case, the subordinate r10bios link back through a 1715 * borrowed master_bio pointer, and the counter in the master 1716 * includes a ref from each subordinate. 1717 */ 1718 /* First, we decide what to do and set ->bi_end_io 1719 * To end_sync_read if we want to read, and 1720 * end_sync_write if we will want to write. 1721 */ 1722 1723 max_sync = RESYNC_PAGES << (PAGE_SHIFT-9); 1724 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 1725 /* recovery... the complicated one */ 1726 int i, j, k; 1727 r10_bio = NULL; 1728 1729 for (i=0 ; i<conf->raid_disks; i++) 1730 if (conf->mirrors[i].rdev && 1731 !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) { 1732 int still_degraded = 0; 1733 /* want to reconstruct this device */ 1734 r10bio_t *rb2 = r10_bio; 1735 sector_t sect = raid10_find_virt(conf, sector_nr, i); 1736 int must_sync; 1737 /* Unless we are doing a full sync, we only need 1738 * to recover the block if it is set in the bitmap 1739 */ 1740 must_sync = bitmap_start_sync(mddev->bitmap, sect, 1741 &sync_blocks, 1); 1742 if (sync_blocks < max_sync) 1743 max_sync = sync_blocks; 1744 if (!must_sync && 1745 !conf->fullsync) { 1746 /* yep, skip the sync_blocks here, but don't assume 1747 * that there will never be anything to do here 1748 */ 1749 chunks_skipped = -1; 1750 continue; 1751 } 1752 1753 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); 1754 raise_barrier(conf, rb2 != NULL); 1755 atomic_set(&r10_bio->remaining, 0); 1756 1757 r10_bio->master_bio = (struct bio*)rb2; 1758 if (rb2) 1759 atomic_inc(&rb2->remaining); 1760 r10_bio->mddev = mddev; 1761 set_bit(R10BIO_IsRecover, &r10_bio->state); 1762 r10_bio->sector = sect; 1763 1764 raid10_find_phys(conf, r10_bio); 1765 /* Need to check if this section will still be 1766 * degraded 1767 */ 1768 for (j=0; j<conf->copies;j++) { 1769 int d = r10_bio->devs[j].devnum; 1770 if (conf->mirrors[d].rdev == NULL || 1771 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) { 1772 still_degraded = 1; 1773 break; 1774 } 1775 } 1776 must_sync = bitmap_start_sync(mddev->bitmap, sect, 1777 &sync_blocks, still_degraded); 1778 1779 for (j=0; j<conf->copies;j++) { 1780 int d = r10_bio->devs[j].devnum; 1781 if (conf->mirrors[d].rdev && 1782 test_bit(In_sync, &conf->mirrors[d].rdev->flags)) { 1783 /* This is where we read from */ 1784 bio = r10_bio->devs[0].bio; 1785 bio->bi_next = biolist; 1786 biolist = bio; 1787 bio->bi_private = r10_bio; 1788 bio->bi_end_io = end_sync_read; 1789 bio->bi_rw = READ; 1790 bio->bi_sector = r10_bio->devs[j].addr + 1791 conf->mirrors[d].rdev->data_offset; 1792 bio->bi_bdev = conf->mirrors[d].rdev->bdev; 1793 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1794 atomic_inc(&r10_bio->remaining); 1795 /* and we write to 'i' */ 1796 1797 for (k=0; k<conf->copies; k++) 1798 if (r10_bio->devs[k].devnum == i) 1799 break; 1800 BUG_ON(k == conf->copies); 1801 bio = r10_bio->devs[1].bio; 1802 bio->bi_next = biolist; 1803 biolist = bio; 1804 bio->bi_private = r10_bio; 1805 bio->bi_end_io = end_sync_write; 1806 bio->bi_rw = WRITE; 1807 bio->bi_sector = r10_bio->devs[k].addr + 1808 conf->mirrors[i].rdev->data_offset; 1809 bio->bi_bdev = conf->mirrors[i].rdev->bdev; 1810 1811 r10_bio->devs[0].devnum = d; 1812 r10_bio->devs[1].devnum = i; 1813 1814 break; 1815 } 1816 } 1817 if (j == conf->copies) { 1818 /* Cannot recover, so abort the recovery */ 1819 put_buf(r10_bio); 1820 r10_bio = rb2; 1821 if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery)) 1822 printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n", 1823 mdname(mddev)); 1824 break; 1825 } 1826 } 1827 if (biolist == NULL) { 1828 while (r10_bio) { 1829 r10bio_t *rb2 = r10_bio; 1830 r10_bio = (r10bio_t*) rb2->master_bio; 1831 rb2->master_bio = NULL; 1832 put_buf(rb2); 1833 } 1834 goto giveup; 1835 } 1836 } else { 1837 /* resync. Schedule a read for every block at this virt offset */ 1838 int count = 0; 1839 1840 if (!bitmap_start_sync(mddev->bitmap, sector_nr, 1841 &sync_blocks, mddev->degraded) && 1842 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { 1843 /* We can skip this block */ 1844 *skipped = 1; 1845 return sync_blocks + sectors_skipped; 1846 } 1847 if (sync_blocks < max_sync) 1848 max_sync = sync_blocks; 1849 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); 1850 1851 r10_bio->mddev = mddev; 1852 atomic_set(&r10_bio->remaining, 0); 1853 raise_barrier(conf, 0); 1854 conf->next_resync = sector_nr; 1855 1856 r10_bio->master_bio = NULL; 1857 r10_bio->sector = sector_nr; 1858 set_bit(R10BIO_IsSync, &r10_bio->state); 1859 raid10_find_phys(conf, r10_bio); 1860 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; 1861 1862 for (i=0; i<conf->copies; i++) { 1863 int d = r10_bio->devs[i].devnum; 1864 bio = r10_bio->devs[i].bio; 1865 bio->bi_end_io = NULL; 1866 clear_bit(BIO_UPTODATE, &bio->bi_flags); 1867 if (conf->mirrors[d].rdev == NULL || 1868 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) 1869 continue; 1870 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1871 atomic_inc(&r10_bio->remaining); 1872 bio->bi_next = biolist; 1873 biolist = bio; 1874 bio->bi_private = r10_bio; 1875 bio->bi_end_io = end_sync_read; 1876 bio->bi_rw = READ; 1877 bio->bi_sector = r10_bio->devs[i].addr + 1878 conf->mirrors[d].rdev->data_offset; 1879 bio->bi_bdev = conf->mirrors[d].rdev->bdev; 1880 count++; 1881 } 1882 1883 if (count < 2) { 1884 for (i=0; i<conf->copies; i++) { 1885 int d = r10_bio->devs[i].devnum; 1886 if (r10_bio->devs[i].bio->bi_end_io) 1887 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 1888 } 1889 put_buf(r10_bio); 1890 biolist = NULL; 1891 goto giveup; 1892 } 1893 } 1894 1895 for (bio = biolist; bio ; bio=bio->bi_next) { 1896 1897 bio->bi_flags &= ~(BIO_POOL_MASK - 1); 1898 if (bio->bi_end_io) 1899 bio->bi_flags |= 1 << BIO_UPTODATE; 1900 bio->bi_vcnt = 0; 1901 bio->bi_idx = 0; 1902 bio->bi_phys_segments = 0; 1903 bio->bi_hw_segments = 0; 1904 bio->bi_size = 0; 1905 } 1906 1907 nr_sectors = 0; 1908 if (sector_nr + max_sync < max_sector) 1909 max_sector = sector_nr + max_sync; 1910 do { 1911 struct page *page; 1912 int len = PAGE_SIZE; 1913 disk = 0; 1914 if (sector_nr + (len>>9) > max_sector) 1915 len = (max_sector - sector_nr) << 9; 1916 if (len == 0) 1917 break; 1918 for (bio= biolist ; bio ; bio=bio->bi_next) { 1919 page = bio->bi_io_vec[bio->bi_vcnt].bv_page; 1920 if (bio_add_page(bio, page, len, 0) == 0) { 1921 /* stop here */ 1922 struct bio *bio2; 1923 bio->bi_io_vec[bio->bi_vcnt].bv_page = page; 1924 for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { 1925 /* remove last page from this bio */ 1926 bio2->bi_vcnt--; 1927 bio2->bi_size -= len; 1928 bio2->bi_flags &= ~(1<< BIO_SEG_VALID); 1929 } 1930 goto bio_full; 1931 } 1932 disk = i; 1933 } 1934 nr_sectors += len>>9; 1935 sector_nr += len>>9; 1936 } while (biolist->bi_vcnt < RESYNC_PAGES); 1937 bio_full: 1938 r10_bio->sectors = nr_sectors; 1939 1940 while (biolist) { 1941 bio = biolist; 1942 biolist = biolist->bi_next; 1943 1944 bio->bi_next = NULL; 1945 r10_bio = bio->bi_private; 1946 r10_bio->sectors = nr_sectors; 1947 1948 if (bio->bi_end_io == end_sync_read) { 1949 md_sync_acct(bio->bi_bdev, nr_sectors); 1950 generic_make_request(bio); 1951 } 1952 } 1953 1954 if (sectors_skipped) 1955 /* pretend they weren't skipped, it makes 1956 * no important difference in this case 1957 */ 1958 md_done_sync(mddev, sectors_skipped, 1); 1959 1960 return sectors_skipped + nr_sectors; 1961 giveup: 1962 /* There is nowhere to write, so all non-sync 1963 * drives must be failed, so try the next chunk... 1964 */ 1965 { 1966 sector_t sec = max_sector - sector_nr; 1967 sectors_skipped += sec; 1968 chunks_skipped ++; 1969 sector_nr = max_sector; 1970 goto skipped; 1971 } 1972} 1973 1974static int run(mddev_t *mddev) 1975{ 1976 conf_t *conf; 1977 int i, disk_idx; 1978 mirror_info_t *disk; 1979 mdk_rdev_t *rdev; 1980 struct list_head *tmp; 1981 int nc, fc, fo; 1982 sector_t stride, size; 1983 1984 if (mddev->chunk_size == 0) { 1985 printk(KERN_ERR "md/raid10: non-zero chunk size required.\n"); 1986 return -EINVAL; 1987 } 1988 1989 nc = mddev->layout & 255; 1990 fc = (mddev->layout >> 8) & 255; 1991 fo = mddev->layout & (1<<16); 1992 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || 1993 (mddev->layout >> 17)) { 1994 printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", 1995 mdname(mddev), mddev->layout); 1996 goto out; 1997 } 1998 /* 1999 * copy the already verified devices into our private RAID10 2000 * bookkeeping area. [whatever we allocate in run(), 2001 * should be freed in stop()] 2002 */ 2003 conf = kzalloc(sizeof(conf_t), GFP_KERNEL); 2004 mddev->private = conf; 2005 if (!conf) { 2006 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", 2007 mdname(mddev)); 2008 goto out; 2009 } 2010 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, 2011 GFP_KERNEL); 2012 if (!conf->mirrors) { 2013 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", 2014 mdname(mddev)); 2015 goto out_free_conf; 2016 } 2017 2018 conf->tmppage = alloc_page(GFP_KERNEL); 2019 if (!conf->tmppage) 2020 goto out_free_conf; 2021 2022 conf->mddev = mddev; 2023 conf->raid_disks = mddev->raid_disks; 2024 conf->near_copies = nc; 2025 conf->far_copies = fc; 2026 conf->copies = nc*fc; 2027 conf->far_offset = fo; 2028 conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; 2029 conf->chunk_shift = ffz(~mddev->chunk_size) - 9; 2030 size = mddev->size >> (conf->chunk_shift-1); 2031 sector_div(size, fc); 2032 size = size * conf->raid_disks; 2033 sector_div(size, nc); 2034 /* 'size' is now the number of chunks in the array */ 2035 /* calculate "used chunks per device" in 'stride' */ 2036 stride = size * conf->copies; 2037 2038 /* We need to round up when dividing by raid_disks to 2039 * get the stride size. 2040 */ 2041 stride += conf->raid_disks - 1; 2042 sector_div(stride, conf->raid_disks); 2043 mddev->size = stride << (conf->chunk_shift-1); 2044 2045 if (fo) 2046 stride = 1; 2047 else 2048 sector_div(stride, fc); 2049 conf->stride = stride << conf->chunk_shift; 2050 2051 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, 2052 r10bio_pool_free, conf); 2053 if (!conf->r10bio_pool) { 2054 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", 2055 mdname(mddev)); 2056 goto out_free_conf; 2057 } 2058 2059 ITERATE_RDEV(mddev, rdev, tmp) { 2060 disk_idx = rdev->raid_disk; 2061 if (disk_idx >= mddev->raid_disks 2062 || disk_idx < 0) 2063 continue; 2064 disk = conf->mirrors + disk_idx; 2065 2066 disk->rdev = rdev; 2067 2068 blk_queue_stack_limits(mddev->queue, 2069 rdev->bdev->bd_disk->queue); 2070 /* as we don't honour merge_bvec_fn, we must never risk 2071 * violating it, so limit ->max_sector to one PAGE, as 2072 * a one page request is never in violation. 2073 */ 2074 if (rdev->bdev->bd_disk->queue->merge_bvec_fn && 2075 mddev->queue->max_sectors > (PAGE_SIZE>>9)) 2076 mddev->queue->max_sectors = (PAGE_SIZE>>9); 2077 2078 disk->head_position = 0; 2079 } 2080 spin_lock_init(&conf->device_lock); 2081 INIT_LIST_HEAD(&conf->retry_list); 2082 2083 spin_lock_init(&conf->resync_lock); 2084 init_waitqueue_head(&conf->wait_barrier); 2085 2086 /* need to check that every block has at least one working mirror */ 2087 if (!enough(conf)) { 2088 printk(KERN_ERR "raid10: not enough operational mirrors for %s\n", 2089 mdname(mddev)); 2090 goto out_free_conf; 2091 } 2092 2093 mddev->degraded = 0; 2094 for (i = 0; i < conf->raid_disks; i++) { 2095 2096 disk = conf->mirrors + i; 2097 2098 if (!disk->rdev || 2099 !test_bit(In_sync, &disk->rdev->flags)) { 2100 disk->head_position = 0; 2101 mddev->degraded++; 2102 } 2103 } 2104 2105 2106 mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10"); 2107 if (!mddev->thread) { 2108 printk(KERN_ERR 2109 "raid10: couldn't allocate thread for %s\n", 2110 mdname(mddev)); 2111 goto out_free_conf; 2112 } 2113 2114 printk(KERN_INFO 2115 "raid10: raid set %s active with %d out of %d devices\n", 2116 mdname(mddev), mddev->raid_disks - mddev->degraded, 2117 mddev->raid_disks); 2118 /* 2119 * Ok, everything is just fine now 2120 */ 2121 mddev->array_size = size << (conf->chunk_shift-1); 2122 mddev->resync_max_sectors = size << conf->chunk_shift; 2123 2124 mddev->queue->unplug_fn = raid10_unplug; 2125 mddev->queue->issue_flush_fn = raid10_issue_flush; 2126 mddev->queue->backing_dev_info.congested_fn = raid10_congested; 2127 mddev->queue->backing_dev_info.congested_data = mddev; 2128 2129 /* Calculate max read-ahead size. 2130 * We need to readahead at least twice a whole stripe.... 2131 * maybe... 2132 */ 2133 { 2134 int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE); 2135 stripe /= conf->near_copies; 2136 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 2137 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 2138 } 2139 2140 if (conf->near_copies < mddev->raid_disks) 2141 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); 2142 return 0; 2143 2144out_free_conf: 2145 if (conf->r10bio_pool) 2146 mempool_destroy(conf->r10bio_pool); 2147 safe_put_page(conf->tmppage); 2148 kfree(conf->mirrors); 2149 kfree(conf); 2150 mddev->private = NULL; 2151out: 2152 return -EIO; 2153} 2154 2155static int stop(mddev_t *mddev) 2156{ 2157 conf_t *conf = mddev_to_conf(mddev); 2158 2159 md_unregister_thread(mddev->thread); 2160 mddev->thread = NULL; 2161 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 2162 if (conf->r10bio_pool) 2163 mempool_destroy(conf->r10bio_pool); 2164 kfree(conf->mirrors); 2165 kfree(conf); 2166 mddev->private = NULL; 2167 return 0; 2168} 2169 2170static void raid10_quiesce(mddev_t *mddev, int state) 2171{ 2172 conf_t *conf = mddev_to_conf(mddev); 2173 2174 switch(state) { 2175 case 1: 2176 raise_barrier(conf, 0); 2177 break; 2178 case 0: 2179 lower_barrier(conf); 2180 break; 2181 } 2182 if (mddev->thread) { 2183 if (mddev->bitmap) 2184 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; 2185 else 2186 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; 2187 md_wakeup_thread(mddev->thread); 2188 } 2189} 2190 2191static struct mdk_personality raid10_personality = 2192{ 2193 .name = "raid10", 2194 .level = 10, 2195 .owner = THIS_MODULE, 2196 .make_request = make_request, 2197 .run = run, 2198 .stop = stop, 2199 .status = status, 2200 .error_handler = error, 2201 .hot_add_disk = raid10_add_disk, 2202 .hot_remove_disk= raid10_remove_disk, 2203 .spare_active = raid10_spare_active, 2204 .sync_request = sync_request, 2205 .quiesce = raid10_quiesce, 2206}; 2207 2208static int __init raid_init(void) 2209{ 2210 return register_md_personality(&raid10_personality); 2211} 2212 2213static void raid_exit(void) 2214{ 2215 unregister_md_personality(&raid10_personality); 2216} 2217 2218module_init(raid_init); 2219module_exit(raid_exit); 2220MODULE_LICENSE("GPL"); 2221MODULE_ALIAS("md-personality-9"); /* RAID10 */ 2222MODULE_ALIAS("md-raid10"); 2223MODULE_ALIAS("md-level-10"); 2224