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 55 static void unplug_slaves(mddev_t *mddev); 56 57 static void allow_barrier(conf_t *conf); 58 static void lower_barrier(conf_t *conf); 59 60 static 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 74 static 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 */ 92 static 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; 137 138 out_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; 145 out_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 } 151 152 static 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 } 171 172 static 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 } 183 184 static 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 } 197 198 static 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 } 206 207 static 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 */ 226 static 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 */ 238 static 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 } 245 246 static 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 } 289 290 static 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 */ 370 371 static 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 } 418 419 static 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 */ 456 static 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 */ 487 488 /* 489 * FIXME: possibly should rethink readbalancing and do it differently 490 * depending on near_copies / far_copies geometry. 491 */ 492 static int read_balance(conf_t *conf, r10bio_t *r10_bio) 493 { 494 const unsigned long this_sector = r10_bio->sector; 495 int disk, slot, nslot; 496 const int sectors = r10_bio->sectors; 497 sector_t new_distance, current_distance; 498 mdk_rdev_t *rdev; 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 (recovery is ok), or below 505 * the resync window. We take the first readable disk when 506 * above the resync window. 507 */ 508 if (conf->mddev->recovery_cp < MaxSector 509 && (this_sector + sectors >= conf->next_resync)) { 510 /* make sure that disk is operational */ 511 slot = 0; 512 disk = r10_bio->devs[slot].devnum; 513 514 while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL || 515 r10_bio->devs[slot].bio == IO_BLOCKED || 516 !test_bit(In_sync, &rdev->flags)) { 517 slot++; 518 if (slot == conf->copies) { 519 slot = 0; 520 disk = -1; 521 break; 522 } 523 disk = r10_bio->devs[slot].devnum; 524 } 525 goto rb_out; 526 } 527 528 529 /* make sure the disk is operational */ 530 slot = 0; 531 disk = r10_bio->devs[slot].devnum; 532 while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL || 533 r10_bio->devs[slot].bio == IO_BLOCKED || 534 !test_bit(In_sync, &rdev->flags)) { 535 slot ++; 536 if (slot == conf->copies) { 537 disk = -1; 538 goto rb_out; 539 } 540 disk = r10_bio->devs[slot].devnum; 541 } 542 543 544 current_distance = abs(r10_bio->devs[slot].addr - 545 conf->mirrors[disk].head_position); 546 547 /* Find the disk whose head is closest */ 548 549 for (nslot = slot; nslot < conf->copies; nslot++) { 550 int ndisk = r10_bio->devs[nslot].devnum; 551 552 553 if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL || 554 r10_bio->devs[nslot].bio == IO_BLOCKED || 555 !test_bit(In_sync, &rdev->flags)) 556 continue; 557 558 /* This optimisation is debatable, and completely destroys 559 * sequential read speed for 'far copies' arrays. So only 560 * keep it for 'near' arrays, and review those later. 561 */ 562 if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) { 563 disk = ndisk; 564 slot = nslot; 565 break; 566 } 567 new_distance = abs(r10_bio->devs[nslot].addr - 568 conf->mirrors[ndisk].head_position); 569 if (new_distance < current_distance) { 570 current_distance = new_distance; 571 disk = ndisk; 572 slot = nslot; 573 } 574 } 575 576 rb_out: 577 r10_bio->read_slot = slot; 578 /* conf->next_seq_sect = this_sector + sectors;*/ 579 580 if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL) 581 atomic_inc(&conf->mirrors[disk].rdev->nr_pending); 582 else 583 disk = -1; 584 rcu_read_unlock(); 585 586 return disk; 587 } 588 589 static void unplug_slaves(mddev_t *mddev) 590 { 591 conf_t *conf = mddev_to_conf(mddev); 592 int i; 593 594 rcu_read_lock(); 595 for (i=0; i<mddev->raid_disks; i++) { 596 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 597 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 598 request_queue_t *r_queue = bdev_get_queue(rdev->bdev); 599 600 atomic_inc(&rdev->nr_pending); 601 rcu_read_unlock(); 602 603 if (r_queue->unplug_fn) 604 r_queue->unplug_fn(r_queue); 605 606 rdev_dec_pending(rdev, mddev); 607 rcu_read_lock(); 608 } 609 } 610 rcu_read_unlock(); 611 } 612 613 static void raid10_unplug(request_queue_t *q) 614 { 615 mddev_t *mddev = q->queuedata; 616 617 unplug_slaves(q->queuedata); 618 md_wakeup_thread(mddev->thread); 619 } 620 621 static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk, 622 sector_t *error_sector) 623 { 624 mddev_t *mddev = q->queuedata; 625 conf_t *conf = mddev_to_conf(mddev); 626 int i, ret = 0; 627 628 rcu_read_lock(); 629 for (i=0; i<mddev->raid_disks && ret == 0; i++) { 630 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 631 if (rdev && !test_bit(Faulty, &rdev->flags)) { 632 struct block_device *bdev = rdev->bdev; 633 request_queue_t *r_queue = bdev_get_queue(bdev); 634 635 if (!r_queue->issue_flush_fn) 636 ret = -EOPNOTSUPP; 637 else { 638 atomic_inc(&rdev->nr_pending); 639 rcu_read_unlock(); 640 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, 641 error_sector); 642 rdev_dec_pending(rdev, mddev); 643 rcu_read_lock(); 644 } 645 } 646 } 647 rcu_read_unlock(); 648 return ret; 649 } 650 651 static int raid10_congested(void *data, int bits) 652 { 653 mddev_t *mddev = data; 654 conf_t *conf = mddev_to_conf(mddev); 655 int i, ret = 0; 656 657 rcu_read_lock(); 658 for (i = 0; i < mddev->raid_disks && ret == 0; i++) { 659 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 660 if (rdev && !test_bit(Faulty, &rdev->flags)) { 661 request_queue_t *q = bdev_get_queue(rdev->bdev); 662 663 ret |= bdi_congested(&q->backing_dev_info, bits); 664 } 665 } 666 rcu_read_unlock(); 667 return ret; 668 } 669 670 671 /* Barriers.... 672 * Sometimes we need to suspend IO while we do something else, 673 * either some resync/recovery, or reconfigure the array. 674 * To do this we raise a 'barrier'. 675 * The 'barrier' is a counter that can be raised multiple times 676 * to count how many activities are happening which preclude 677 * normal IO. 678 * We can only raise the barrier if there is no pending IO. 679 * i.e. if nr_pending == 0. 680 * We choose only to raise the barrier if no-one is waiting for the 681 * barrier to go down. This means that as soon as an IO request 682 * is ready, no other operations which require a barrier will start 683 * until the IO request has had a chance. 684 * 685 * So: regular IO calls 'wait_barrier'. When that returns there 686 * is no backgroup IO happening, It must arrange to call 687 * allow_barrier when it has finished its IO. 688 * backgroup IO calls must call raise_barrier. Once that returns 689 * there is no normal IO happeing. It must arrange to call 690 * lower_barrier when the particular background IO completes. 691 */ 692 #define RESYNC_DEPTH 32 693 694 static void raise_barrier(conf_t *conf, int force) 695 { 696 BUG_ON(force && !conf->barrier); 697 spin_lock_irq(&conf->resync_lock); 698 699 /* Wait until no block IO is waiting (unless 'force') */ 700 wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, 701 conf->resync_lock, 702 raid10_unplug(conf->mddev->queue)); 703 704 /* block any new IO from starting */ 705 conf->barrier++; 706 707 /* No wait for all pending IO to complete */ 708 wait_event_lock_irq(conf->wait_barrier, 709 !conf->nr_pending && conf->barrier < RESYNC_DEPTH, 710 conf->resync_lock, 711 raid10_unplug(conf->mddev->queue)); 712 713 spin_unlock_irq(&conf->resync_lock); 714 } 715 716 static void lower_barrier(conf_t *conf) 717 { 718 unsigned long flags; 719 spin_lock_irqsave(&conf->resync_lock, flags); 720 conf->barrier--; 721 spin_unlock_irqrestore(&conf->resync_lock, flags); 722 wake_up(&conf->wait_barrier); 723 } 724 725 static void wait_barrier(conf_t *conf) 726 { 727 spin_lock_irq(&conf->resync_lock); 728 if (conf->barrier) { 729 conf->nr_waiting++; 730 wait_event_lock_irq(conf->wait_barrier, !conf->barrier, 731 conf->resync_lock, 732 raid10_unplug(conf->mddev->queue)); 733 conf->nr_waiting--; 734 } 735 conf->nr_pending++; 736 spin_unlock_irq(&conf->resync_lock); 737 } 738 739 static void allow_barrier(conf_t *conf) 740 { 741 unsigned long flags; 742 spin_lock_irqsave(&conf->resync_lock, flags); 743 conf->nr_pending--; 744 spin_unlock_irqrestore(&conf->resync_lock, flags); 745 wake_up(&conf->wait_barrier); 746 } 747 748 static void freeze_array(conf_t *conf) 749 { 750 /* stop syncio and normal IO and wait for everything to 751 * go quiet. 752 * We increment barrier and nr_waiting, and then 753 * wait until barrier+nr_pending match nr_queued+2 754 */ 755 spin_lock_irq(&conf->resync_lock); 756 conf->barrier++; 757 conf->nr_waiting++; 758 wait_event_lock_irq(conf->wait_barrier, 759 conf->barrier+conf->nr_pending == conf->nr_queued+2, 760 conf->resync_lock, 761 raid10_unplug(conf->mddev->queue)); 762 spin_unlock_irq(&conf->resync_lock); 763 } 764 765 static void unfreeze_array(conf_t *conf) 766 { 767 /* reverse the effect of the freeze */ 768 spin_lock_irq(&conf->resync_lock); 769 conf->barrier--; 770 conf->nr_waiting--; 771 wake_up(&conf->wait_barrier); 772 spin_unlock_irq(&conf->resync_lock); 773 } 774 775 static int make_request(request_queue_t *q, struct bio * bio) 776 { 777 mddev_t *mddev = q->queuedata; 778 conf_t *conf = mddev_to_conf(mddev); 779 mirror_info_t *mirror; 780 r10bio_t *r10_bio; 781 struct bio *read_bio; 782 int i; 783 int chunk_sects = conf->chunk_mask + 1; 784 const int rw = bio_data_dir(bio); 785 const int do_sync = bio_sync(bio); 786 struct bio_list bl; 787 unsigned long flags; 788 789 if (unlikely(bio_barrier(bio))) { 790 bio_endio(bio, bio->bi_size, -EOPNOTSUPP); 791 return 0; 792 } 793 794 /* If this request crosses a chunk boundary, we need to 795 * split it. This will only happen for 1 PAGE (or less) requests. 796 */ 797 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) 798 > chunk_sects && 799 conf->near_copies < conf->raid_disks)) { 800 struct bio_pair *bp; 801 /* Sanity check -- queue functions should prevent this happening */ 802 if (bio->bi_vcnt != 1 || 803 bio->bi_idx != 0) 804 goto bad_map; 805 /* This is a one page bio that upper layers 806 * refuse to split for us, so we need to split it. 807 */ 808 bp = bio_split(bio, bio_split_pool, 809 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); 810 if (make_request(q, &bp->bio1)) 811 generic_make_request(&bp->bio1); 812 if (make_request(q, &bp->bio2)) 813 generic_make_request(&bp->bio2); 814 815 bio_pair_release(bp); 816 return 0; 817 bad_map: 818 printk("raid10_make_request bug: can't convert block across chunks" 819 " or bigger than %dk %llu %d\n", chunk_sects/2, 820 (unsigned long long)bio->bi_sector, bio->bi_size >> 10); 821 822 bio_io_error(bio, bio->bi_size); 823 return 0; 824 } 825 826 md_write_start(mddev, bio); 827 828 /* 829 * Register the new request and wait if the reconstruction 830 * thread has put up a bar for new requests. 831 * Continue immediately if no resync is active currently. 832 */ 833 wait_barrier(conf); 834 835 disk_stat_inc(mddev->gendisk, ios[rw]); 836 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); 837 838 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); 839 840 r10_bio->master_bio = bio; 841 r10_bio->sectors = bio->bi_size >> 9; 842 843 r10_bio->mddev = mddev; 844 r10_bio->sector = bio->bi_sector; 845 r10_bio->state = 0; 846 847 if (rw == READ) { 848 /* 849 * read balancing logic: 850 */ 851 int disk = read_balance(conf, r10_bio); 852 int slot = r10_bio->read_slot; 853 if (disk < 0) { 854 raid_end_bio_io(r10_bio); 855 return 0; 856 } 857 mirror = conf->mirrors + disk; 858 859 read_bio = bio_clone(bio, GFP_NOIO); 860 861 r10_bio->devs[slot].bio = read_bio; 862 863 read_bio->bi_sector = r10_bio->devs[slot].addr + 864 mirror->rdev->data_offset; 865 read_bio->bi_bdev = mirror->rdev->bdev; 866 read_bio->bi_end_io = raid10_end_read_request; 867 read_bio->bi_rw = READ | do_sync; 868 read_bio->bi_private = r10_bio; 869 870 generic_make_request(read_bio); 871 return 0; 872 } 873 874 /* 875 * WRITE: 876 */ 877 /* first select target devices under spinlock and 878 * inc refcount on their rdev. Record them by setting 879 * bios[x] to bio 880 */ 881 raid10_find_phys(conf, r10_bio); 882 rcu_read_lock(); 883 for (i = 0; i < conf->copies; i++) { 884 int d = r10_bio->devs[i].devnum; 885 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev); 886 if (rdev && 887 !test_bit(Faulty, &rdev->flags)) { 888 atomic_inc(&rdev->nr_pending); 889 r10_bio->devs[i].bio = bio; 890 } else { 891 r10_bio->devs[i].bio = NULL; 892 set_bit(R10BIO_Degraded, &r10_bio->state); 893 } 894 } 895 rcu_read_unlock(); 896 897 atomic_set(&r10_bio->remaining, 0); 898 899 bio_list_init(&bl); 900 for (i = 0; i < conf->copies; i++) { 901 struct bio *mbio; 902 int d = r10_bio->devs[i].devnum; 903 if (!r10_bio->devs[i].bio) 904 continue; 905 906 mbio = bio_clone(bio, GFP_NOIO); 907 r10_bio->devs[i].bio = mbio; 908 909 mbio->bi_sector = r10_bio->devs[i].addr+ 910 conf->mirrors[d].rdev->data_offset; 911 mbio->bi_bdev = conf->mirrors[d].rdev->bdev; 912 mbio->bi_end_io = raid10_end_write_request; 913 mbio->bi_rw = WRITE | do_sync; 914 mbio->bi_private = r10_bio; 915 916 atomic_inc(&r10_bio->remaining); 917 bio_list_add(&bl, mbio); 918 } 919 920 bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0); 921 spin_lock_irqsave(&conf->device_lock, flags); 922 bio_list_merge(&conf->pending_bio_list, &bl); 923 blk_plug_device(mddev->queue); 924 spin_unlock_irqrestore(&conf->device_lock, flags); 925 926 if (do_sync) 927 md_wakeup_thread(mddev->thread); 928 929 return 0; 930 } 931 932 static void status(struct seq_file *seq, mddev_t *mddev) 933 { 934 conf_t *conf = mddev_to_conf(mddev); 935 int i; 936 937 if (conf->near_copies < conf->raid_disks) 938 seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); 939 if (conf->near_copies > 1) 940 seq_printf(seq, " %d near-copies", conf->near_copies); 941 if (conf->far_copies > 1) { 942 if (conf->far_offset) 943 seq_printf(seq, " %d offset-copies", conf->far_copies); 944 else 945 seq_printf(seq, " %d far-copies", conf->far_copies); 946 } 947 seq_printf(seq, " [%d/%d] [", conf->raid_disks, 948 conf->raid_disks - mddev->degraded); 949 for (i = 0; i < conf->raid_disks; i++) 950 seq_printf(seq, "%s", 951 conf->mirrors[i].rdev && 952 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_"); 953 seq_printf(seq, "]"); 954 } 955 956 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 957 { 958 char b[BDEVNAME_SIZE]; 959 conf_t *conf = mddev_to_conf(mddev); 960 961 /* 962 * If it is not operational, then we have already marked it as dead 963 * else if it is the last working disks, ignore the error, let the 964 * next level up know. 965 * else mark the drive as failed 966 */ 967 if (test_bit(In_sync, &rdev->flags) 968 && conf->raid_disks-mddev->degraded == 1) 969 /* 970 * Don't fail the drive, just return an IO error. 971 * The test should really be more sophisticated than 972 * "working_disks == 1", but it isn't critical, and 973 * can wait until we do more sophisticated "is the drive 974 * really dead" tests... 975 */ 976 return; 977 if (test_and_clear_bit(In_sync, &rdev->flags)) { 978 unsigned long flags; 979 spin_lock_irqsave(&conf->device_lock, flags); 980 mddev->degraded++; 981 spin_unlock_irqrestore(&conf->device_lock, flags); 982 /* 983 * if recovery is running, make sure it aborts. 984 */ 985 set_bit(MD_RECOVERY_ERR, &mddev->recovery); 986 } 987 set_bit(Faulty, &rdev->flags); 988 set_bit(MD_CHANGE_DEVS, &mddev->flags); 989 printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n" 990 " Operation continuing on %d devices\n", 991 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); 992 } 993 994 static void print_conf(conf_t *conf) 995 { 996 int i; 997 mirror_info_t *tmp; 998 999 printk("RAID10 conf printout:\n"); 1000 if (!conf) { 1001 printk("(!conf)\n"); 1002 return; 1003 } 1004 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, 1005 conf->raid_disks); 1006 1007 for (i = 0; i < conf->raid_disks; i++) { 1008 char b[BDEVNAME_SIZE]; 1009 tmp = conf->mirrors + i; 1010 if (tmp->rdev) 1011 printk(" disk %d, wo:%d, o:%d, dev:%s\n", 1012 i, !test_bit(In_sync, &tmp->rdev->flags), 1013 !test_bit(Faulty, &tmp->rdev->flags), 1014 bdevname(tmp->rdev->bdev,b)); 1015 } 1016 } 1017 1018 static void close_sync(conf_t *conf) 1019 { 1020 wait_barrier(conf); 1021 allow_barrier(conf); 1022 1023 mempool_destroy(conf->r10buf_pool); 1024 conf->r10buf_pool = NULL; 1025 } 1026 1027 /* check if there are enough drives for 1028 * every block to appear on atleast one 1029 */ 1030 static int enough(conf_t *conf) 1031 { 1032 int first = 0; 1033 1034 do { 1035 int n = conf->copies; 1036 int cnt = 0; 1037 while (n--) { 1038 if (conf->mirrors[first].rdev) 1039 cnt++; 1040 first = (first+1) % conf->raid_disks; 1041 } 1042 if (cnt == 0) 1043 return 0; 1044 } while (first != 0); 1045 return 1; 1046 } 1047 1048 static int raid10_spare_active(mddev_t *mddev) 1049 { 1050 int i; 1051 conf_t *conf = mddev->private; 1052 mirror_info_t *tmp; 1053 1054 /* 1055 * Find all non-in_sync disks within the RAID10 configuration 1056 * and mark them in_sync 1057 */ 1058 for (i = 0; i < conf->raid_disks; i++) { 1059 tmp = conf->mirrors + i; 1060 if (tmp->rdev 1061 && !test_bit(Faulty, &tmp->rdev->flags) 1062 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 1063 unsigned long flags; 1064 spin_lock_irqsave(&conf->device_lock, flags); 1065 mddev->degraded--; 1066 spin_unlock_irqrestore(&conf->device_lock, flags); 1067 } 1068 } 1069 1070 print_conf(conf); 1071 return 0; 1072 } 1073 1074 1075 static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 1076 { 1077 conf_t *conf = mddev->private; 1078 int found = 0; 1079 int mirror; 1080 mirror_info_t *p; 1081 1082 if (mddev->recovery_cp < MaxSector) 1083 /* only hot-add to in-sync arrays, as recovery is 1084 * very different from resync 1085 */ 1086 return 0; 1087 if (!enough(conf)) 1088 return 0; 1089 1090 if (rdev->saved_raid_disk >= 0 && 1091 conf->mirrors[rdev->saved_raid_disk].rdev == NULL) 1092 mirror = rdev->saved_raid_disk; 1093 else 1094 mirror = 0; 1095 for ( ; mirror < mddev->raid_disks; mirror++) 1096 if ( !(p=conf->mirrors+mirror)->rdev) { 1097 1098 blk_queue_stack_limits(mddev->queue, 1099 rdev->bdev->bd_disk->queue); 1100 /* as we don't honour merge_bvec_fn, we must never risk 1101 * violating it, so limit ->max_sector to one PAGE, as 1102 * a one page request is never in violation. 1103 */ 1104 if (rdev->bdev->bd_disk->queue->merge_bvec_fn && 1105 mddev->queue->max_sectors > (PAGE_SIZE>>9)) 1106 mddev->queue->max_sectors = (PAGE_SIZE>>9); 1107 1108 p->head_position = 0; 1109 rdev->raid_disk = mirror; 1110 found = 1; 1111 if (rdev->saved_raid_disk != mirror) 1112 conf->fullsync = 1; 1113 rcu_assign_pointer(p->rdev, rdev); 1114 break; 1115 } 1116 1117 print_conf(conf); 1118 return found; 1119 } 1120 1121 static int raid10_remove_disk(mddev_t *mddev, int number) 1122 { 1123 conf_t *conf = mddev->private; 1124 int err = 0; 1125 mdk_rdev_t *rdev; 1126 mirror_info_t *p = conf->mirrors+ number; 1127 1128 print_conf(conf); 1129 rdev = p->rdev; 1130 if (rdev) { 1131 if (test_bit(In_sync, &rdev->flags) || 1132 atomic_read(&rdev->nr_pending)) { 1133 err = -EBUSY; 1134 goto abort; 1135 } 1136 p->rdev = NULL; 1137 synchronize_rcu(); 1138 if (atomic_read(&rdev->nr_pending)) { 1139 /* lost the race, try later */ 1140 err = -EBUSY; 1141 p->rdev = rdev; 1142 } 1143 } 1144 abort: 1145 1146 print_conf(conf); 1147 return err; 1148 } 1149 1150 1151 static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error) 1152 { 1153 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); 1154 conf_t *conf = mddev_to_conf(r10_bio->mddev); 1155 int i,d; 1156 1157 if (bio->bi_size) 1158 return 1; 1159 1160 for (i=0; i<conf->copies; i++) 1161 if (r10_bio->devs[i].bio == bio) 1162 break; 1163 BUG_ON(i == conf->copies); 1164 update_head_pos(i, r10_bio); 1165 d = r10_bio->devs[i].devnum; 1166 1167 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 1168 set_bit(R10BIO_Uptodate, &r10_bio->state); 1169 else { 1170 atomic_add(r10_bio->sectors, 1171 &conf->mirrors[d].rdev->corrected_errors); 1172 if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) 1173 md_error(r10_bio->mddev, 1174 conf->mirrors[d].rdev); 1175 } 1176 1177 /* for reconstruct, we always reschedule after a read. 1178 * for resync, only after all reads 1179 */ 1180 if (test_bit(R10BIO_IsRecover, &r10_bio->state) || 1181 atomic_dec_and_test(&r10_bio->remaining)) { 1182 /* we have read all the blocks, 1183 * do the comparison in process context in raid10d 1184 */ 1185 reschedule_retry(r10_bio); 1186 } 1187 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); 1188 return 0; 1189 } 1190 1191 static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error) 1192 { 1193 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 1194 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); 1195 mddev_t *mddev = r10_bio->mddev; 1196 conf_t *conf = mddev_to_conf(mddev); 1197 int i,d; 1198 1199 if (bio->bi_size) 1200 return 1; 1201 1202 for (i = 0; i < conf->copies; i++) 1203 if (r10_bio->devs[i].bio == bio) 1204 break; 1205 d = r10_bio->devs[i].devnum; 1206 1207 if (!uptodate) 1208 md_error(mddev, conf->mirrors[d].rdev); 1209 update_head_pos(i, r10_bio); 1210 1211 while (atomic_dec_and_test(&r10_bio->remaining)) { 1212 if (r10_bio->master_bio == NULL) { 1213 /* the primary of several recovery bios */ 1214 md_done_sync(mddev, r10_bio->sectors, 1); 1215 put_buf(r10_bio); 1216 break; 1217 } else { 1218 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; 1219 put_buf(r10_bio); 1220 r10_bio = r10_bio2; 1221 } 1222 } 1223 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 1224 return 0; 1225 } 1226 1227 /* 1228 * Note: sync and recover and handled very differently for raid10 1229 * This code is for resync. 1230 * For resync, we read through virtual addresses and read all blocks. 1231 * If there is any error, we schedule a write. The lowest numbered 1232 * drive is authoritative. 1233 * However requests come for physical address, so we need to map. 1234 * For every physical address there are raid_disks/copies virtual addresses, 1235 * which is always are least one, but is not necessarly an integer. 1236 * This means that a physical address can span multiple chunks, so we may 1237 * have to submit multiple io requests for a single sync request. 1238 */ 1239 /* 1240 * We check if all blocks are in-sync and only write to blocks that 1241 * aren't in sync 1242 */ 1243 static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) 1244 { 1245 conf_t *conf = mddev_to_conf(mddev); 1246 int i, first; 1247 struct bio *tbio, *fbio; 1248 1249 atomic_set(&r10_bio->remaining, 1); 1250 1251 /* find the first device with a block */ 1252 for (i=0; i<conf->copies; i++) 1253 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) 1254 break; 1255 1256 if (i == conf->copies) 1257 goto done; 1258 1259 first = i; 1260 fbio = r10_bio->devs[i].bio; 1261 1262 /* now find blocks with errors */ 1263 for (i=0 ; i < conf->copies ; i++) { 1264 int j, d; 1265 int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); 1266 1267 tbio = r10_bio->devs[i].bio; 1268 1269 if (tbio->bi_end_io != end_sync_read) 1270 continue; 1271 if (i == first) 1272 continue; 1273 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) { 1274 /* We know that the bi_io_vec layout is the same for 1275 * both 'first' and 'i', so we just compare them. 1276 * All vec entries are PAGE_SIZE; 1277 */ 1278 for (j = 0; j < vcnt; j++) 1279 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), 1280 page_address(tbio->bi_io_vec[j].bv_page), 1281 PAGE_SIZE)) 1282 break; 1283 if (j == vcnt) 1284 continue; 1285 mddev->resync_mismatches += r10_bio->sectors; 1286 } 1287 if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) 1288 /* Don't fix anything. */ 1289 continue; 1290 /* Ok, we need to write this bio 1291 * First we need to fixup bv_offset, bv_len and 1292 * bi_vecs, as the read request might have corrupted these 1293 */ 1294 tbio->bi_vcnt = vcnt; 1295 tbio->bi_size = r10_bio->sectors << 9; 1296 tbio->bi_idx = 0; 1297 tbio->bi_phys_segments = 0; 1298 tbio->bi_hw_segments = 0; 1299 tbio->bi_hw_front_size = 0; 1300 tbio->bi_hw_back_size = 0; 1301 tbio->bi_flags &= ~(BIO_POOL_MASK - 1); 1302 tbio->bi_flags |= 1 << BIO_UPTODATE; 1303 tbio->bi_next = NULL; 1304 tbio->bi_rw = WRITE; 1305 tbio->bi_private = r10_bio; 1306 tbio->bi_sector = r10_bio->devs[i].addr; 1307 1308 for (j=0; j < vcnt ; j++) { 1309 tbio->bi_io_vec[j].bv_offset = 0; 1310 tbio->bi_io_vec[j].bv_len = PAGE_SIZE; 1311 1312 memcpy(page_address(tbio->bi_io_vec[j].bv_page), 1313 page_address(fbio->bi_io_vec[j].bv_page), 1314 PAGE_SIZE); 1315 } 1316 tbio->bi_end_io = end_sync_write; 1317 1318 d = r10_bio->devs[i].devnum; 1319 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1320 atomic_inc(&r10_bio->remaining); 1321 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); 1322 1323 tbio->bi_sector += conf->mirrors[d].rdev->data_offset; 1324 tbio->bi_bdev = conf->mirrors[d].rdev->bdev; 1325 generic_make_request(tbio); 1326 } 1327 1328 done: 1329 if (atomic_dec_and_test(&r10_bio->remaining)) { 1330 md_done_sync(mddev, r10_bio->sectors, 1); 1331 put_buf(r10_bio); 1332 } 1333 } 1334 1335 /* 1336 * Now for the recovery code. 1337 * Recovery happens across physical sectors. 1338 * We recover all non-is_sync drives by finding the virtual address of 1339 * each, and then choose a working drive that also has that virt address. 1340 * There is a separate r10_bio for each non-in_sync drive. 1341 * Only the first two slots are in use. The first for reading, 1342 * The second for writing. 1343 * 1344 */ 1345 1346 static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) 1347 { 1348 conf_t *conf = mddev_to_conf(mddev); 1349 int i, d; 1350 struct bio *bio, *wbio; 1351 1352 1353 /* move the pages across to the second bio 1354 * and submit the write request 1355 */ 1356 bio = r10_bio->devs[0].bio; 1357 wbio = r10_bio->devs[1].bio; 1358 for (i=0; i < wbio->bi_vcnt; i++) { 1359 struct page *p = bio->bi_io_vec[i].bv_page; 1360 bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; 1361 wbio->bi_io_vec[i].bv_page = p; 1362 } 1363 d = r10_bio->devs[1].devnum; 1364 1365 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1366 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); 1367 if (test_bit(R10BIO_Uptodate, &r10_bio->state)) 1368 generic_make_request(wbio); 1369 else 1370 bio_endio(wbio, wbio->bi_size, -EIO); 1371 } 1372 1373 1374 /* 1375 * This is a kernel thread which: 1376 * 1377 * 1. Retries failed read operations on working mirrors. 1378 * 2. Updates the raid superblock when problems encounter. 1379 * 3. Performs writes following reads for array synchronising. 1380 */ 1381 1382 static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) 1383 { 1384 int sect = 0; /* Offset from r10_bio->sector */ 1385 int sectors = r10_bio->sectors; 1386 mdk_rdev_t*rdev; 1387 while(sectors) { 1388 int s = sectors; 1389 int sl = r10_bio->read_slot; 1390 int success = 0; 1391 int start; 1392 1393 if (s > (PAGE_SIZE>>9)) 1394 s = PAGE_SIZE >> 9; 1395 1396 rcu_read_lock(); 1397 do { 1398 int d = r10_bio->devs[sl].devnum; 1399 rdev = rcu_dereference(conf->mirrors[d].rdev); 1400 if (rdev && 1401 test_bit(In_sync, &rdev->flags)) { 1402 atomic_inc(&rdev->nr_pending); 1403 rcu_read_unlock(); 1404 success = sync_page_io(rdev->bdev, 1405 r10_bio->devs[sl].addr + 1406 sect + rdev->data_offset, 1407 s<<9, 1408 conf->tmppage, READ); 1409 rdev_dec_pending(rdev, mddev); 1410 rcu_read_lock(); 1411 if (success) 1412 break; 1413 } 1414 sl++; 1415 if (sl == conf->copies) 1416 sl = 0; 1417 } while (!success && sl != r10_bio->read_slot); 1418 rcu_read_unlock(); 1419 1420 if (!success) { 1421 /* Cannot read from anywhere -- bye bye array */ 1422 int dn = r10_bio->devs[r10_bio->read_slot].devnum; 1423 md_error(mddev, conf->mirrors[dn].rdev); 1424 break; 1425 } 1426 1427 start = sl; 1428 /* write it back and re-read */ 1429 rcu_read_lock(); 1430 while (sl != r10_bio->read_slot) { 1431 int d; 1432 if (sl==0) 1433 sl = conf->copies; 1434 sl--; 1435 d = r10_bio->devs[sl].devnum; 1436 rdev = rcu_dereference(conf->mirrors[d].rdev); 1437 if (rdev && 1438 test_bit(In_sync, &rdev->flags)) { 1439 atomic_inc(&rdev->nr_pending); 1440 rcu_read_unlock(); 1441 atomic_add(s, &rdev->corrected_errors); 1442 if (sync_page_io(rdev->bdev, 1443 r10_bio->devs[sl].addr + 1444 sect + rdev->data_offset, 1445 s<<9, conf->tmppage, WRITE) 1446 == 0) 1447 /* Well, this device is dead */ 1448 md_error(mddev, rdev); 1449 rdev_dec_pending(rdev, mddev); 1450 rcu_read_lock(); 1451 } 1452 } 1453 sl = start; 1454 while (sl != r10_bio->read_slot) { 1455 int d; 1456 if (sl==0) 1457 sl = conf->copies; 1458 sl--; 1459 d = r10_bio->devs[sl].devnum; 1460 rdev = rcu_dereference(conf->mirrors[d].rdev); 1461 if (rdev && 1462 test_bit(In_sync, &rdev->flags)) { 1463 char b[BDEVNAME_SIZE]; 1464 atomic_inc(&rdev->nr_pending); 1465 rcu_read_unlock(); 1466 if (sync_page_io(rdev->bdev, 1467 r10_bio->devs[sl].addr + 1468 sect + rdev->data_offset, 1469 s<<9, conf->tmppage, READ) == 0) 1470 /* Well, this device is dead */ 1471 md_error(mddev, rdev); 1472 else 1473 printk(KERN_INFO 1474 "raid10:%s: read error corrected" 1475 " (%d sectors at %llu on %s)\n", 1476 mdname(mddev), s, 1477 (unsigned long long)(sect+ 1478 rdev->data_offset), 1479 bdevname(rdev->bdev, b)); 1480 1481 rdev_dec_pending(rdev, mddev); 1482 rcu_read_lock(); 1483 } 1484 } 1485 rcu_read_unlock(); 1486 1487 sectors -= s; 1488 sect += s; 1489 } 1490 } 1491 1492 static void raid10d(mddev_t *mddev) 1493 { 1494 r10bio_t *r10_bio; 1495 struct bio *bio; 1496 unsigned long flags; 1497 conf_t *conf = mddev_to_conf(mddev); 1498 struct list_head *head = &conf->retry_list; 1499 int unplug=0; 1500 mdk_rdev_t *rdev; 1501 1502 md_check_recovery(mddev); 1503 1504 for (;;) { 1505 char b[BDEVNAME_SIZE]; 1506 spin_lock_irqsave(&conf->device_lock, flags); 1507 1508 if (conf->pending_bio_list.head) { 1509 bio = bio_list_get(&conf->pending_bio_list); 1510 blk_remove_plug(mddev->queue); 1511 spin_unlock_irqrestore(&conf->device_lock, flags); 1512 /* flush any pending bitmap writes to disk before proceeding w/ I/O */ 1513 if (bitmap_unplug(mddev->bitmap) != 0) 1514 printk("%s: bitmap file write failed!\n", mdname(mddev)); 1515 1516 while (bio) { /* submit pending writes */ 1517 struct bio *next = bio->bi_next; 1518 bio->bi_next = NULL; 1519 generic_make_request(bio); 1520 bio = next; 1521 } 1522 unplug = 1; 1523 1524 continue; 1525 } 1526 1527 if (list_empty(head)) 1528 break; 1529 r10_bio = list_entry(head->prev, r10bio_t, retry_list); 1530 list_del(head->prev); 1531 conf->nr_queued--; 1532 spin_unlock_irqrestore(&conf->device_lock, flags); 1533 1534 mddev = r10_bio->mddev; 1535 conf = mddev_to_conf(mddev); 1536 if (test_bit(R10BIO_IsSync, &r10_bio->state)) { 1537 sync_request_write(mddev, r10_bio); 1538 unplug = 1; 1539 } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { 1540 recovery_request_write(mddev, r10_bio); 1541 unplug = 1; 1542 } else { 1543 int mirror; 1544 /* we got a read error. Maybe the drive is bad. Maybe just 1545 * the block and we can fix it. 1546 * We freeze all other IO, and try reading the block from 1547 * other devices. When we find one, we re-write 1548 * and check it that fixes the read error. 1549 * This is all done synchronously while the array is 1550 * frozen. 1551 */ 1552 if (mddev->ro == 0) { 1553 freeze_array(conf); 1554 fix_read_error(conf, mddev, r10_bio); 1555 unfreeze_array(conf); 1556 } 1557 1558 bio = r10_bio->devs[r10_bio->read_slot].bio; 1559 r10_bio->devs[r10_bio->read_slot].bio = 1560 mddev->ro ? IO_BLOCKED : NULL; 1561 bio_put(bio); 1562 mirror = read_balance(conf, r10_bio); 1563 if (mirror == -1) { 1564 printk(KERN_ALERT "raid10: %s: unrecoverable I/O" 1565 " read error for block %llu\n", 1566 bdevname(bio->bi_bdev,b), 1567 (unsigned long long)r10_bio->sector); 1568 raid_end_bio_io(r10_bio); 1569 } else { 1570 const int do_sync = bio_sync(r10_bio->master_bio); 1571 rdev = conf->mirrors[mirror].rdev; 1572 if (printk_ratelimit()) 1573 printk(KERN_ERR "raid10: %s: redirecting sector %llu to" 1574 " another mirror\n", 1575 bdevname(rdev->bdev,b), 1576 (unsigned long long)r10_bio->sector); 1577 bio = bio_clone(r10_bio->master_bio, GFP_NOIO); 1578 r10_bio->devs[r10_bio->read_slot].bio = bio; 1579 bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr 1580 + rdev->data_offset; 1581 bio->bi_bdev = rdev->bdev; 1582 bio->bi_rw = READ | do_sync; 1583 bio->bi_private = r10_bio; 1584 bio->bi_end_io = raid10_end_read_request; 1585 unplug = 1; 1586 generic_make_request(bio); 1587 } 1588 } 1589 } 1590 spin_unlock_irqrestore(&conf->device_lock, flags); 1591 if (unplug) 1592 unplug_slaves(mddev); 1593 } 1594 1595 1596 static int init_resync(conf_t *conf) 1597 { 1598 int buffs; 1599 1600 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; 1601 BUG_ON(conf->r10buf_pool); 1602 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); 1603 if (!conf->r10buf_pool) 1604 return -ENOMEM; 1605 conf->next_resync = 0; 1606 return 0; 1607 } 1608 1609 /* 1610 * perform a "sync" on one "block" 1611 * 1612 * We need to make sure that no normal I/O request - particularly write 1613 * requests - conflict with active sync requests. 1614 * 1615 * This is achieved by tracking pending requests and a 'barrier' concept 1616 * that can be installed to exclude normal IO requests. 1617 * 1618 * Resync and recovery are handled very differently. 1619 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. 1620 * 1621 * For resync, we iterate over virtual addresses, read all copies, 1622 * and update if there are differences. If only one copy is live, 1623 * skip it. 1624 * For recovery, we iterate over physical addresses, read a good 1625 * value for each non-in_sync drive, and over-write. 1626 * 1627 * So, for recovery we may have several outstanding complex requests for a 1628 * given address, one for each out-of-sync device. We model this by allocating 1629 * a number of r10_bio structures, one for each out-of-sync device. 1630 * As we setup these structures, we collect all bio's together into a list 1631 * which we then process collectively to add pages, and then process again 1632 * to pass to generic_make_request. 1633 * 1634 * The r10_bio structures are linked using a borrowed master_bio pointer. 1635 * This link is counted in ->remaining. When the r10_bio that points to NULL 1636 * has its remaining count decremented to 0, the whole complex operation 1637 * is complete. 1638 * 1639 */ 1640 1641 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 1642 { 1643 conf_t *conf = mddev_to_conf(mddev); 1644 r10bio_t *r10_bio; 1645 struct bio *biolist = NULL, *bio; 1646 sector_t max_sector, nr_sectors; 1647 int disk; 1648 int i; 1649 int max_sync; 1650 int sync_blocks; 1651 1652 sector_t sectors_skipped = 0; 1653 int chunks_skipped = 0; 1654 1655 if (!conf->r10buf_pool) 1656 if (init_resync(conf)) 1657 return 0; 1658 1659 skipped: 1660 max_sector = mddev->size << 1; 1661 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) 1662 max_sector = mddev->resync_max_sectors; 1663 if (sector_nr >= max_sector) { 1664 /* If we aborted, we need to abort the 1665 * sync on the 'current' bitmap chucks (there can 1666 * be several when recovering multiple devices). 1667 * as we may have started syncing it but not finished. 1668 * We can find the current address in 1669 * mddev->curr_resync, but for recovery, 1670 * we need to convert that to several 1671 * virtual addresses. 1672 */ 1673 if (mddev->curr_resync < max_sector) { /* aborted */ 1674 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) 1675 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 1676 &sync_blocks, 1); 1677 else for (i=0; i<conf->raid_disks; i++) { 1678 sector_t sect = 1679 raid10_find_virt(conf, mddev->curr_resync, i); 1680 bitmap_end_sync(mddev->bitmap, sect, 1681 &sync_blocks, 1); 1682 } 1683 } else /* completed sync */ 1684 conf->fullsync = 0; 1685 1686 bitmap_close_sync(mddev->bitmap); 1687 close_sync(conf); 1688 *skipped = 1; 1689 return sectors_skipped; 1690 } 1691 if (chunks_skipped >= conf->raid_disks) { 1692 /* if there has been nothing to do on any drive, 1693 * then there is nothing to do at all.. 1694 */ 1695 *skipped = 1; 1696 return (max_sector - sector_nr) + sectors_skipped; 1697 } 1698 1699 /* make sure whole request will fit in a chunk - if chunks 1700 * are meaningful 1701 */ 1702 if (conf->near_copies < conf->raid_disks && 1703 max_sector > (sector_nr | conf->chunk_mask)) 1704 max_sector = (sector_nr | conf->chunk_mask) + 1; 1705 /* 1706 * If there is non-resync activity waiting for us then 1707 * put in a delay to throttle resync. 1708 */ 1709 if (!go_faster && conf->nr_waiting) 1710 msleep_interruptible(1000); 1711 1712 /* Again, very different code for resync and recovery. 1713 * Both must result in an r10bio with a list of bios that 1714 * have bi_end_io, bi_sector, bi_bdev set, 1715 * and bi_private set to the r10bio. 1716 * For recovery, we may actually create several r10bios 1717 * with 2 bios in each, that correspond to the bios in the main one. 1718 * In this case, the subordinate r10bios link back through a 1719 * borrowed master_bio pointer, and the counter in the master 1720 * includes a ref from each subordinate. 1721 */ 1722 /* First, we decide what to do and set ->bi_end_io 1723 * To end_sync_read if we want to read, and 1724 * end_sync_write if we will want to write. 1725 */ 1726 1727 max_sync = RESYNC_PAGES << (PAGE_SHIFT-9); 1728 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 1729 /* recovery... the complicated one */ 1730 int i, j, k; 1731 r10_bio = NULL; 1732 1733 for (i=0 ; i<conf->raid_disks; i++) 1734 if (conf->mirrors[i].rdev && 1735 !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) { 1736 int still_degraded = 0; 1737 /* want to reconstruct this device */ 1738 r10bio_t *rb2 = r10_bio; 1739 sector_t sect = raid10_find_virt(conf, sector_nr, i); 1740 int must_sync; 1741 /* Unless we are doing a full sync, we only need 1742 * to recover the block if it is set in the bitmap 1743 */ 1744 must_sync = bitmap_start_sync(mddev->bitmap, sect, 1745 &sync_blocks, 1); 1746 if (sync_blocks < max_sync) 1747 max_sync = sync_blocks; 1748 if (!must_sync && 1749 !conf->fullsync) { 1750 /* yep, skip the sync_blocks here, but don't assume 1751 * that there will never be anything to do here 1752 */ 1753 chunks_skipped = -1; 1754 continue; 1755 } 1756 1757 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); 1758 raise_barrier(conf, rb2 != NULL); 1759 atomic_set(&r10_bio->remaining, 0); 1760 1761 r10_bio->master_bio = (struct bio*)rb2; 1762 if (rb2) 1763 atomic_inc(&rb2->remaining); 1764 r10_bio->mddev = mddev; 1765 set_bit(R10BIO_IsRecover, &r10_bio->state); 1766 r10_bio->sector = sect; 1767 1768 raid10_find_phys(conf, r10_bio); 1769 /* Need to check if this section will still be 1770 * degraded 1771 */ 1772 for (j=0; j<conf->copies;j++) { 1773 int d = r10_bio->devs[j].devnum; 1774 if (conf->mirrors[d].rdev == NULL || 1775 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) { 1776 still_degraded = 1; 1777 break; 1778 } 1779 } 1780 must_sync = bitmap_start_sync(mddev->bitmap, sect, 1781 &sync_blocks, still_degraded); 1782 1783 for (j=0; j<conf->copies;j++) { 1784 int d = r10_bio->devs[j].devnum; 1785 if (conf->mirrors[d].rdev && 1786 test_bit(In_sync, &conf->mirrors[d].rdev->flags)) { 1787 /* This is where we read from */ 1788 bio = r10_bio->devs[0].bio; 1789 bio->bi_next = biolist; 1790 biolist = bio; 1791 bio->bi_private = r10_bio; 1792 bio->bi_end_io = end_sync_read; 1793 bio->bi_rw = READ; 1794 bio->bi_sector = r10_bio->devs[j].addr + 1795 conf->mirrors[d].rdev->data_offset; 1796 bio->bi_bdev = conf->mirrors[d].rdev->bdev; 1797 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1798 atomic_inc(&r10_bio->remaining); 1799 /* and we write to 'i' */ 1800 1801 for (k=0; k<conf->copies; k++) 1802 if (r10_bio->devs[k].devnum == i) 1803 break; 1804 BUG_ON(k == conf->copies); 1805 bio = r10_bio->devs[1].bio; 1806 bio->bi_next = biolist; 1807 biolist = bio; 1808 bio->bi_private = r10_bio; 1809 bio->bi_end_io = end_sync_write; 1810 bio->bi_rw = WRITE; 1811 bio->bi_sector = r10_bio->devs[k].addr + 1812 conf->mirrors[i].rdev->data_offset; 1813 bio->bi_bdev = conf->mirrors[i].rdev->bdev; 1814 1815 r10_bio->devs[0].devnum = d; 1816 r10_bio->devs[1].devnum = i; 1817 1818 break; 1819 } 1820 } 1821 if (j == conf->copies) { 1822 /* Cannot recover, so abort the recovery */ 1823 put_buf(r10_bio); 1824 r10_bio = rb2; 1825 if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery)) 1826 printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n", 1827 mdname(mddev)); 1828 break; 1829 } 1830 } 1831 if (biolist == NULL) { 1832 while (r10_bio) { 1833 r10bio_t *rb2 = r10_bio; 1834 r10_bio = (r10bio_t*) rb2->master_bio; 1835 rb2->master_bio = NULL; 1836 put_buf(rb2); 1837 } 1838 goto giveup; 1839 } 1840 } else { 1841 /* resync. Schedule a read for every block at this virt offset */ 1842 int count = 0; 1843 1844 if (!bitmap_start_sync(mddev->bitmap, sector_nr, 1845 &sync_blocks, mddev->degraded) && 1846 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { 1847 /* We can skip this block */ 1848 *skipped = 1; 1849 return sync_blocks + sectors_skipped; 1850 } 1851 if (sync_blocks < max_sync) 1852 max_sync = sync_blocks; 1853 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); 1854 1855 r10_bio->mddev = mddev; 1856 atomic_set(&r10_bio->remaining, 0); 1857 raise_barrier(conf, 0); 1858 conf->next_resync = sector_nr; 1859 1860 r10_bio->master_bio = NULL; 1861 r10_bio->sector = sector_nr; 1862 set_bit(R10BIO_IsSync, &r10_bio->state); 1863 raid10_find_phys(conf, r10_bio); 1864 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; 1865 1866 for (i=0; i<conf->copies; i++) { 1867 int d = r10_bio->devs[i].devnum; 1868 bio = r10_bio->devs[i].bio; 1869 bio->bi_end_io = NULL; 1870 if (conf->mirrors[d].rdev == NULL || 1871 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) 1872 continue; 1873 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1874 atomic_inc(&r10_bio->remaining); 1875 bio->bi_next = biolist; 1876 biolist = bio; 1877 bio->bi_private = r10_bio; 1878 bio->bi_end_io = end_sync_read; 1879 bio->bi_rw = READ; 1880 bio->bi_sector = r10_bio->devs[i].addr + 1881 conf->mirrors[d].rdev->data_offset; 1882 bio->bi_bdev = conf->mirrors[d].rdev->bdev; 1883 count++; 1884 } 1885 1886 if (count < 2) { 1887 for (i=0; i<conf->copies; i++) { 1888 int d = r10_bio->devs[i].devnum; 1889 if (r10_bio->devs[i].bio->bi_end_io) 1890 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 1891 } 1892 put_buf(r10_bio); 1893 biolist = NULL; 1894 goto giveup; 1895 } 1896 } 1897 1898 for (bio = biolist; bio ; bio=bio->bi_next) { 1899 1900 bio->bi_flags &= ~(BIO_POOL_MASK - 1); 1901 if (bio->bi_end_io) 1902 bio->bi_flags |= 1 << BIO_UPTODATE; 1903 bio->bi_vcnt = 0; 1904 bio->bi_idx = 0; 1905 bio->bi_phys_segments = 0; 1906 bio->bi_hw_segments = 0; 1907 bio->bi_size = 0; 1908 } 1909 1910 nr_sectors = 0; 1911 if (sector_nr + max_sync < max_sector) 1912 max_sector = sector_nr + max_sync; 1913 do { 1914 struct page *page; 1915 int len = PAGE_SIZE; 1916 disk = 0; 1917 if (sector_nr + (len>>9) > max_sector) 1918 len = (max_sector - sector_nr) << 9; 1919 if (len == 0) 1920 break; 1921 for (bio= biolist ; bio ; bio=bio->bi_next) { 1922 page = bio->bi_io_vec[bio->bi_vcnt].bv_page; 1923 if (bio_add_page(bio, page, len, 0) == 0) { 1924 /* stop here */ 1925 struct bio *bio2; 1926 bio->bi_io_vec[bio->bi_vcnt].bv_page = page; 1927 for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { 1928 /* remove last page from this bio */ 1929 bio2->bi_vcnt--; 1930 bio2->bi_size -= len; 1931 bio2->bi_flags &= ~(1<< BIO_SEG_VALID); 1932 } 1933 goto bio_full; 1934 } 1935 disk = i; 1936 } 1937 nr_sectors += len>>9; 1938 sector_nr += len>>9; 1939 } while (biolist->bi_vcnt < RESYNC_PAGES); 1940 bio_full: 1941 r10_bio->sectors = nr_sectors; 1942 1943 while (biolist) { 1944 bio = biolist; 1945 biolist = biolist->bi_next; 1946 1947 bio->bi_next = NULL; 1948 r10_bio = bio->bi_private; 1949 r10_bio->sectors = nr_sectors; 1950 1951 if (bio->bi_end_io == end_sync_read) { 1952 md_sync_acct(bio->bi_bdev, nr_sectors); 1953 generic_make_request(bio); 1954 } 1955 } 1956 1957 if (sectors_skipped) 1958 /* pretend they weren't skipped, it makes 1959 * no important difference in this case 1960 */ 1961 md_done_sync(mddev, sectors_skipped, 1); 1962 1963 return sectors_skipped + nr_sectors; 1964 giveup: 1965 /* There is nowhere to write, so all non-sync 1966 * drives must be failed, so try the next chunk... 1967 */ 1968 { 1969 sector_t sec = max_sector - sector_nr; 1970 sectors_skipped += sec; 1971 chunks_skipped ++; 1972 sector_nr = max_sector; 1973 goto skipped; 1974 } 1975 } 1976 1977 static int run(mddev_t *mddev) 1978 { 1979 conf_t *conf; 1980 int i, disk_idx; 1981 mirror_info_t *disk; 1982 mdk_rdev_t *rdev; 1983 struct list_head *tmp; 1984 int nc, fc, fo; 1985 sector_t stride, size; 1986 1987 if (mddev->chunk_size == 0) { 1988 printk(KERN_ERR "md/raid10: non-zero chunk size required.\n"); 1989 return -EINVAL; 1990 } 1991 1992 nc = mddev->layout & 255; 1993 fc = (mddev->layout >> 8) & 255; 1994 fo = mddev->layout & (1<<16); 1995 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || 1996 (mddev->layout >> 17)) { 1997 printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", 1998 mdname(mddev), mddev->layout); 1999 goto out; 2000 } 2001 /* 2002 * copy the already verified devices into our private RAID10 2003 * bookkeeping area. [whatever we allocate in run(), 2004 * should be freed in stop()] 2005 */ 2006 conf = kzalloc(sizeof(conf_t), GFP_KERNEL); 2007 mddev->private = conf; 2008 if (!conf) { 2009 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", 2010 mdname(mddev)); 2011 goto out; 2012 } 2013 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, 2014 GFP_KERNEL); 2015 if (!conf->mirrors) { 2016 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", 2017 mdname(mddev)); 2018 goto out_free_conf; 2019 } 2020 2021 conf->tmppage = alloc_page(GFP_KERNEL); 2022 if (!conf->tmppage) 2023 goto out_free_conf; 2024 2025 conf->mddev = mddev; 2026 conf->raid_disks = mddev->raid_disks; 2027 conf->near_copies = nc; 2028 conf->far_copies = fc; 2029 conf->copies = nc*fc; 2030 conf->far_offset = fo; 2031 conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; 2032 conf->chunk_shift = ffz(~mddev->chunk_size) - 9; 2033 size = mddev->size >> (conf->chunk_shift-1); 2034 sector_div(size, fc); 2035 size = size * conf->raid_disks; 2036 sector_div(size, nc); 2037 /* 'size' is now the number of chunks in the array */ 2038 /* calculate "used chunks per device" in 'stride' */ 2039 stride = size * conf->copies; 2040 sector_div(stride, conf->raid_disks); 2041 mddev->size = stride << (conf->chunk_shift-1); 2042 2043 if (fo) 2044 stride = 1; 2045 else 2046 sector_div(stride, fc); 2047 conf->stride = stride << conf->chunk_shift; 2048 2049 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, 2050 r10bio_pool_free, conf); 2051 if (!conf->r10bio_pool) { 2052 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", 2053 mdname(mddev)); 2054 goto out_free_conf; 2055 } 2056 2057 ITERATE_RDEV(mddev, rdev, tmp) { 2058 disk_idx = rdev->raid_disk; 2059 if (disk_idx >= mddev->raid_disks 2060 || disk_idx < 0) 2061 continue; 2062 disk = conf->mirrors + disk_idx; 2063 2064 disk->rdev = rdev; 2065 2066 blk_queue_stack_limits(mddev->queue, 2067 rdev->bdev->bd_disk->queue); 2068 /* as we don't honour merge_bvec_fn, we must never risk 2069 * violating it, so limit ->max_sector to one PAGE, as 2070 * a one page request is never in violation. 2071 */ 2072 if (rdev->bdev->bd_disk->queue->merge_bvec_fn && 2073 mddev->queue->max_sectors > (PAGE_SIZE>>9)) 2074 mddev->queue->max_sectors = (PAGE_SIZE>>9); 2075 2076 disk->head_position = 0; 2077 } 2078 spin_lock_init(&conf->device_lock); 2079 INIT_LIST_HEAD(&conf->retry_list); 2080 2081 spin_lock_init(&conf->resync_lock); 2082 init_waitqueue_head(&conf->wait_barrier); 2083 2084 /* need to check that every block has at least one working mirror */ 2085 if (!enough(conf)) { 2086 printk(KERN_ERR "raid10: not enough operational mirrors for %s\n", 2087 mdname(mddev)); 2088 goto out_free_conf; 2089 } 2090 2091 mddev->degraded = 0; 2092 for (i = 0; i < conf->raid_disks; i++) { 2093 2094 disk = conf->mirrors + i; 2095 2096 if (!disk->rdev || 2097 !test_bit(In_sync, &disk->rdev->flags)) { 2098 disk->head_position = 0; 2099 mddev->degraded++; 2100 } 2101 } 2102 2103 2104 mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10"); 2105 if (!mddev->thread) { 2106 printk(KERN_ERR 2107 "raid10: couldn't allocate thread for %s\n", 2108 mdname(mddev)); 2109 goto out_free_conf; 2110 } 2111 2112 printk(KERN_INFO 2113 "raid10: raid set %s active with %d out of %d devices\n", 2114 mdname(mddev), mddev->raid_disks - mddev->degraded, 2115 mddev->raid_disks); 2116 /* 2117 * Ok, everything is just fine now 2118 */ 2119 mddev->array_size = size << (conf->chunk_shift-1); 2120 mddev->resync_max_sectors = size << conf->chunk_shift; 2121 2122 mddev->queue->unplug_fn = raid10_unplug; 2123 mddev->queue->issue_flush_fn = raid10_issue_flush; 2124 mddev->queue->backing_dev_info.congested_fn = raid10_congested; 2125 mddev->queue->backing_dev_info.congested_data = mddev; 2126 2127 /* Calculate max read-ahead size. 2128 * We need to readahead at least twice a whole stripe.... 2129 * maybe... 2130 */ 2131 { 2132 int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE); 2133 stripe /= conf->near_copies; 2134 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 2135 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 2136 } 2137 2138 if (conf->near_copies < mddev->raid_disks) 2139 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); 2140 return 0; 2141 2142 out_free_conf: 2143 if (conf->r10bio_pool) 2144 mempool_destroy(conf->r10bio_pool); 2145 safe_put_page(conf->tmppage); 2146 kfree(conf->mirrors); 2147 kfree(conf); 2148 mddev->private = NULL; 2149 out: 2150 return -EIO; 2151 } 2152 2153 static int stop(mddev_t *mddev) 2154 { 2155 conf_t *conf = mddev_to_conf(mddev); 2156 2157 md_unregister_thread(mddev->thread); 2158 mddev->thread = NULL; 2159 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 2160 if (conf->r10bio_pool) 2161 mempool_destroy(conf->r10bio_pool); 2162 kfree(conf->mirrors); 2163 kfree(conf); 2164 mddev->private = NULL; 2165 return 0; 2166 } 2167 2168 static void raid10_quiesce(mddev_t *mddev, int state) 2169 { 2170 conf_t *conf = mddev_to_conf(mddev); 2171 2172 switch(state) { 2173 case 1: 2174 raise_barrier(conf, 0); 2175 break; 2176 case 0: 2177 lower_barrier(conf); 2178 break; 2179 } 2180 if (mddev->thread) { 2181 if (mddev->bitmap) 2182 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; 2183 else 2184 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; 2185 md_wakeup_thread(mddev->thread); 2186 } 2187 } 2188 2189 static struct mdk_personality raid10_personality = 2190 { 2191 .name = "raid10", 2192 .level = 10, 2193 .owner = THIS_MODULE, 2194 .make_request = make_request, 2195 .run = run, 2196 .stop = stop, 2197 .status = status, 2198 .error_handler = error, 2199 .hot_add_disk = raid10_add_disk, 2200 .hot_remove_disk= raid10_remove_disk, 2201 .spare_active = raid10_spare_active, 2202 .sync_request = sync_request, 2203 .quiesce = raid10_quiesce, 2204 }; 2205 2206 static int __init raid_init(void) 2207 { 2208 return register_md_personality(&raid10_personality); 2209 } 2210 2211 static void raid_exit(void) 2212 { 2213 unregister_md_personality(&raid10_personality); 2214 } 2215 2216 module_init(raid_init); 2217 module_exit(raid_exit); 2218 MODULE_LICENSE("GPL"); 2219 MODULE_ALIAS("md-personality-9"); /* RAID10 */ 2220 MODULE_ALIAS("md-raid10"); 2221 MODULE_ALIAS("md-level-10"); 2222