1 /* 2 * raid10.c : Multiple Devices driver for Linux 3 * 4 * Copyright (C) 2000-2004 Neil Brown 5 * 6 * RAID-10 support for md. 7 * 8 * Base on code in raid1.c. See raid1.c for futher copyright information. 9 * 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; either version 2, or (at your option) 14 * any later version. 15 * 16 * You should have received a copy of the GNU General Public License 17 * (for example /usr/src/linux/COPYING); if not, write to the Free 18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/slab.h> 22 #include <linux/delay.h> 23 #include <linux/blkdev.h> 24 #include <linux/seq_file.h> 25 #include "md.h" 26 #include "raid10.h" 27 #include "raid0.h" 28 #include "bitmap.h" 29 30 /* 31 * RAID10 provides a combination of RAID0 and RAID1 functionality. 32 * The layout of data is defined by 33 * chunk_size 34 * raid_disks 35 * near_copies (stored in low byte of layout) 36 * far_copies (stored in second byte of layout) 37 * far_offset (stored in bit 16 of layout ) 38 * 39 * The data to be stored is divided into chunks using chunksize. 40 * Each device is divided into far_copies sections. 41 * In each section, chunks are laid out in a style similar to raid0, but 42 * near_copies copies of each chunk is stored (each on a different drive). 43 * The starting device for each section is offset near_copies from the starting 44 * device of the previous section. 45 * Thus they are (near_copies*far_copies) of each chunk, and each is on a different 46 * drive. 47 * near_copies and far_copies must be at least one, and their product is at most 48 * raid_disks. 49 * 50 * If far_offset is true, then the far_copies are handled a bit differently. 51 * The copies are still in different stripes, but instead of be very far apart 52 * on disk, there are adjacent stripes. 53 */ 54 55 /* 56 * Number of guaranteed r10bios in case of extreme VM load: 57 */ 58 #define NR_RAID10_BIOS 256 59 60 static void unplug_slaves(mddev_t *mddev); 61 62 static void allow_barrier(conf_t *conf); 63 static void lower_barrier(conf_t *conf); 64 65 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) 66 { 67 conf_t *conf = data; 68 r10bio_t *r10_bio; 69 int size = offsetof(struct r10bio_s, devs[conf->copies]); 70 71 /* allocate a r10bio with room for raid_disks entries in the bios array */ 72 r10_bio = kzalloc(size, gfp_flags); 73 if (!r10_bio && conf->mddev) 74 unplug_slaves(conf->mddev); 75 76 return r10_bio; 77 } 78 79 static void r10bio_pool_free(void *r10_bio, void *data) 80 { 81 kfree(r10_bio); 82 } 83 84 /* Maximum size of each resync request */ 85 #define RESYNC_BLOCK_SIZE (64*1024) 86 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) 87 /* amount of memory to reserve for resync requests */ 88 #define RESYNC_WINDOW (1024*1024) 89 /* maximum number of concurrent requests, memory permitting */ 90 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE) 91 92 /* 93 * When performing a resync, we need to read and compare, so 94 * we need as many pages are there are copies. 95 * When performing a recovery, we need 2 bios, one for read, 96 * one for write (we recover only one drive per r10buf) 97 * 98 */ 99 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data) 100 { 101 conf_t *conf = data; 102 struct page *page; 103 r10bio_t *r10_bio; 104 struct bio *bio; 105 int i, j; 106 int nalloc; 107 108 r10_bio = r10bio_pool_alloc(gfp_flags, conf); 109 if (!r10_bio) { 110 unplug_slaves(conf->mddev); 111 return NULL; 112 } 113 114 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) 115 nalloc = conf->copies; /* resync */ 116 else 117 nalloc = 2; /* recovery */ 118 119 /* 120 * Allocate bios. 121 */ 122 for (j = nalloc ; j-- ; ) { 123 bio = bio_alloc(gfp_flags, RESYNC_PAGES); 124 if (!bio) 125 goto out_free_bio; 126 r10_bio->devs[j].bio = bio; 127 } 128 /* 129 * Allocate RESYNC_PAGES data pages and attach them 130 * where needed. 131 */ 132 for (j = 0 ; j < nalloc; j++) { 133 bio = r10_bio->devs[j].bio; 134 for (i = 0; i < RESYNC_PAGES; i++) { 135 page = alloc_page(gfp_flags); 136 if (unlikely(!page)) 137 goto out_free_pages; 138 139 bio->bi_io_vec[i].bv_page = page; 140 } 141 } 142 143 return r10_bio; 144 145 out_free_pages: 146 for ( ; i > 0 ; i--) 147 safe_put_page(bio->bi_io_vec[i-1].bv_page); 148 while (j--) 149 for (i = 0; i < RESYNC_PAGES ; i++) 150 safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page); 151 j = -1; 152 out_free_bio: 153 while ( ++j < nalloc ) 154 bio_put(r10_bio->devs[j].bio); 155 r10bio_pool_free(r10_bio, conf); 156 return NULL; 157 } 158 159 static void r10buf_pool_free(void *__r10_bio, void *data) 160 { 161 int i; 162 conf_t *conf = data; 163 r10bio_t *r10bio = __r10_bio; 164 int j; 165 166 for (j=0; j < conf->copies; j++) { 167 struct bio *bio = r10bio->devs[j].bio; 168 if (bio) { 169 for (i = 0; i < RESYNC_PAGES; i++) { 170 safe_put_page(bio->bi_io_vec[i].bv_page); 171 bio->bi_io_vec[i].bv_page = NULL; 172 } 173 bio_put(bio); 174 } 175 } 176 r10bio_pool_free(r10bio, conf); 177 } 178 179 static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) 180 { 181 int i; 182 183 for (i = 0; i < conf->copies; i++) { 184 struct bio **bio = & r10_bio->devs[i].bio; 185 if (*bio && *bio != IO_BLOCKED) 186 bio_put(*bio); 187 *bio = NULL; 188 } 189 } 190 191 static void free_r10bio(r10bio_t *r10_bio) 192 { 193 conf_t *conf = r10_bio->mddev->private; 194 195 /* 196 * Wake up any possible resync thread that waits for the device 197 * to go idle. 198 */ 199 allow_barrier(conf); 200 201 put_all_bios(conf, r10_bio); 202 mempool_free(r10_bio, conf->r10bio_pool); 203 } 204 205 static void put_buf(r10bio_t *r10_bio) 206 { 207 conf_t *conf = r10_bio->mddev->private; 208 209 mempool_free(r10_bio, conf->r10buf_pool); 210 211 lower_barrier(conf); 212 } 213 214 static void reschedule_retry(r10bio_t *r10_bio) 215 { 216 unsigned long flags; 217 mddev_t *mddev = r10_bio->mddev; 218 conf_t *conf = mddev->private; 219 220 spin_lock_irqsave(&conf->device_lock, flags); 221 list_add(&r10_bio->retry_list, &conf->retry_list); 222 conf->nr_queued ++; 223 spin_unlock_irqrestore(&conf->device_lock, flags); 224 225 /* wake up frozen array... */ 226 wake_up(&conf->wait_barrier); 227 228 md_wakeup_thread(mddev->thread); 229 } 230 231 /* 232 * raid_end_bio_io() is called when we have finished servicing a mirrored 233 * operation and are ready to return a success/failure code to the buffer 234 * cache layer. 235 */ 236 static void raid_end_bio_io(r10bio_t *r10_bio) 237 { 238 struct bio *bio = r10_bio->master_bio; 239 240 bio_endio(bio, 241 test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO); 242 free_r10bio(r10_bio); 243 } 244 245 /* 246 * Update disk head position estimator based on IRQ completion info. 247 */ 248 static inline void update_head_pos(int slot, r10bio_t *r10_bio) 249 { 250 conf_t *conf = r10_bio->mddev->private; 251 252 conf->mirrors[r10_bio->devs[slot].devnum].head_position = 253 r10_bio->devs[slot].addr + (r10_bio->sectors); 254 } 255 256 static void raid10_end_read_request(struct bio *bio, int error) 257 { 258 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 259 r10bio_t *r10_bio = bio->bi_private; 260 int slot, dev; 261 conf_t *conf = r10_bio->mddev->private; 262 263 264 slot = r10_bio->read_slot; 265 dev = r10_bio->devs[slot].devnum; 266 /* 267 * this branch is our 'one mirror IO has finished' event handler: 268 */ 269 update_head_pos(slot, r10_bio); 270 271 if (uptodate) { 272 /* 273 * Set R10BIO_Uptodate in our master bio, so that 274 * we will return a good error code to the higher 275 * levels even if IO on some other mirrored buffer fails. 276 * 277 * The 'master' represents the composite IO operation to 278 * user-side. So if something waits for IO, then it will 279 * wait for the 'master' bio. 280 */ 281 set_bit(R10BIO_Uptodate, &r10_bio->state); 282 raid_end_bio_io(r10_bio); 283 } else { 284 /* 285 * oops, read error: 286 */ 287 char b[BDEVNAME_SIZE]; 288 if (printk_ratelimit()) 289 printk(KERN_ERR "md/raid10:%s: %s: rescheduling sector %llu\n", 290 mdname(conf->mddev), 291 bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); 292 reschedule_retry(r10_bio); 293 } 294 295 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); 296 } 297 298 static void raid10_end_write_request(struct bio *bio, int error) 299 { 300 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 301 r10bio_t *r10_bio = bio->bi_private; 302 int slot, dev; 303 conf_t *conf = r10_bio->mddev->private; 304 305 for (slot = 0; slot < conf->copies; slot++) 306 if (r10_bio->devs[slot].bio == bio) 307 break; 308 dev = r10_bio->devs[slot].devnum; 309 310 /* 311 * this branch is our 'one mirror IO has finished' event handler: 312 */ 313 if (!uptodate) { 314 md_error(r10_bio->mddev, conf->mirrors[dev].rdev); 315 /* an I/O failed, we can't clear the bitmap */ 316 set_bit(R10BIO_Degraded, &r10_bio->state); 317 } else 318 /* 319 * Set R10BIO_Uptodate in our master bio, so that 320 * we will return a good error code for to the higher 321 * levels even if IO on some other mirrored buffer fails. 322 * 323 * The 'master' represents the composite IO operation to 324 * user-side. So if something waits for IO, then it will 325 * wait for the 'master' bio. 326 */ 327 set_bit(R10BIO_Uptodate, &r10_bio->state); 328 329 update_head_pos(slot, r10_bio); 330 331 /* 332 * 333 * Let's see if all mirrored write operations have finished 334 * already. 335 */ 336 if (atomic_dec_and_test(&r10_bio->remaining)) { 337 /* clear the bitmap if all writes complete successfully */ 338 bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector, 339 r10_bio->sectors, 340 !test_bit(R10BIO_Degraded, &r10_bio->state), 341 0); 342 md_write_end(r10_bio->mddev); 343 raid_end_bio_io(r10_bio); 344 } 345 346 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); 347 } 348 349 350 /* 351 * RAID10 layout manager 352 * Aswell as the chunksize and raid_disks count, there are two 353 * parameters: near_copies and far_copies. 354 * near_copies * far_copies must be <= raid_disks. 355 * Normally one of these will be 1. 356 * If both are 1, we get raid0. 357 * If near_copies == raid_disks, we get raid1. 358 * 359 * Chunks are layed out in raid0 style with near_copies copies of the 360 * first chunk, followed by near_copies copies of the next chunk and 361 * so on. 362 * If far_copies > 1, then after 1/far_copies of the array has been assigned 363 * as described above, we start again with a device offset of near_copies. 364 * So we effectively have another copy of the whole array further down all 365 * the drives, but with blocks on different drives. 366 * With this layout, and block is never stored twice on the one device. 367 * 368 * raid10_find_phys finds the sector offset of a given virtual sector 369 * on each device that it is on. 370 * 371 * raid10_find_virt does the reverse mapping, from a device and a 372 * sector offset to a virtual address 373 */ 374 375 static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) 376 { 377 int n,f; 378 sector_t sector; 379 sector_t chunk; 380 sector_t stripe; 381 int dev; 382 383 int slot = 0; 384 385 /* now calculate first sector/dev */ 386 chunk = r10bio->sector >> conf->chunk_shift; 387 sector = r10bio->sector & conf->chunk_mask; 388 389 chunk *= conf->near_copies; 390 stripe = chunk; 391 dev = sector_div(stripe, conf->raid_disks); 392 if (conf->far_offset) 393 stripe *= conf->far_copies; 394 395 sector += stripe << conf->chunk_shift; 396 397 /* and calculate all the others */ 398 for (n=0; n < conf->near_copies; n++) { 399 int d = dev; 400 sector_t s = sector; 401 r10bio->devs[slot].addr = sector; 402 r10bio->devs[slot].devnum = d; 403 slot++; 404 405 for (f = 1; f < conf->far_copies; f++) { 406 d += conf->near_copies; 407 if (d >= conf->raid_disks) 408 d -= conf->raid_disks; 409 s += conf->stride; 410 r10bio->devs[slot].devnum = d; 411 r10bio->devs[slot].addr = s; 412 slot++; 413 } 414 dev++; 415 if (dev >= conf->raid_disks) { 416 dev = 0; 417 sector += (conf->chunk_mask + 1); 418 } 419 } 420 BUG_ON(slot != conf->copies); 421 } 422 423 static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) 424 { 425 sector_t offset, chunk, vchunk; 426 427 offset = sector & conf->chunk_mask; 428 if (conf->far_offset) { 429 int fc; 430 chunk = sector >> conf->chunk_shift; 431 fc = sector_div(chunk, conf->far_copies); 432 dev -= fc * conf->near_copies; 433 if (dev < 0) 434 dev += conf->raid_disks; 435 } else { 436 while (sector >= conf->stride) { 437 sector -= conf->stride; 438 if (dev < conf->near_copies) 439 dev += conf->raid_disks - conf->near_copies; 440 else 441 dev -= conf->near_copies; 442 } 443 chunk = sector >> conf->chunk_shift; 444 } 445 vchunk = chunk * conf->raid_disks + dev; 446 sector_div(vchunk, conf->near_copies); 447 return (vchunk << conf->chunk_shift) + offset; 448 } 449 450 /** 451 * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged 452 * @q: request queue 453 * @bvm: properties of new bio 454 * @biovec: the request that could be merged to it. 455 * 456 * Return amount of bytes we can accept at this offset 457 * If near_copies == raid_disk, there are no striping issues, 458 * but in that case, the function isn't called at all. 459 */ 460 static int raid10_mergeable_bvec(struct request_queue *q, 461 struct bvec_merge_data *bvm, 462 struct bio_vec *biovec) 463 { 464 mddev_t *mddev = q->queuedata; 465 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 466 int max; 467 unsigned int chunk_sectors = mddev->chunk_sectors; 468 unsigned int bio_sectors = bvm->bi_size >> 9; 469 470 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; 471 if (max < 0) max = 0; /* bio_add cannot handle a negative return */ 472 if (max <= biovec->bv_len && bio_sectors == 0) 473 return biovec->bv_len; 474 else 475 return max; 476 } 477 478 /* 479 * This routine returns the disk from which the requested read should 480 * be done. There is a per-array 'next expected sequential IO' sector 481 * number - if this matches on the next IO then we use the last disk. 482 * There is also a per-disk 'last know head position' sector that is 483 * maintained from IRQ contexts, both the normal and the resync IO 484 * completion handlers update this position correctly. If there is no 485 * perfect sequential match then we pick the disk whose head is closest. 486 * 487 * If there are 2 mirrors in the same 2 devices, performance degrades 488 * because position is mirror, not device based. 489 * 490 * The rdev for the device selected will have nr_pending incremented. 491 */ 492 493 /* 494 * FIXME: possibly should rethink readbalancing and do it differently 495 * depending on near_copies / far_copies geometry. 496 */ 497 static int read_balance(conf_t *conf, r10bio_t *r10_bio) 498 { 499 const sector_t this_sector = r10_bio->sector; 500 int disk, slot, nslot; 501 const int sectors = r10_bio->sectors; 502 sector_t new_distance, current_distance; 503 mdk_rdev_t *rdev; 504 505 raid10_find_phys(conf, r10_bio); 506 rcu_read_lock(); 507 /* 508 * Check if we can balance. We can balance on the whole 509 * device if no resync is going on (recovery is ok), or below 510 * the resync window. We take the first readable disk when 511 * above the resync window. 512 */ 513 if (conf->mddev->recovery_cp < MaxSector 514 && (this_sector + sectors >= conf->next_resync)) { 515 /* make sure that disk is operational */ 516 slot = 0; 517 disk = r10_bio->devs[slot].devnum; 518 519 while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL || 520 r10_bio->devs[slot].bio == IO_BLOCKED || 521 !test_bit(In_sync, &rdev->flags)) { 522 slot++; 523 if (slot == conf->copies) { 524 slot = 0; 525 disk = -1; 526 break; 527 } 528 disk = r10_bio->devs[slot].devnum; 529 } 530 goto rb_out; 531 } 532 533 534 /* make sure the disk is operational */ 535 slot = 0; 536 disk = r10_bio->devs[slot].devnum; 537 while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL || 538 r10_bio->devs[slot].bio == IO_BLOCKED || 539 !test_bit(In_sync, &rdev->flags)) { 540 slot ++; 541 if (slot == conf->copies) { 542 disk = -1; 543 goto rb_out; 544 } 545 disk = r10_bio->devs[slot].devnum; 546 } 547 548 549 current_distance = abs(r10_bio->devs[slot].addr - 550 conf->mirrors[disk].head_position); 551 552 /* Find the disk whose head is closest, 553 * or - for far > 1 - find the closest to partition beginning */ 554 555 for (nslot = slot; nslot < conf->copies; nslot++) { 556 int ndisk = r10_bio->devs[nslot].devnum; 557 558 559 if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL || 560 r10_bio->devs[nslot].bio == IO_BLOCKED || 561 !test_bit(In_sync, &rdev->flags)) 562 continue; 563 564 /* This optimisation is debatable, and completely destroys 565 * sequential read speed for 'far copies' arrays. So only 566 * keep it for 'near' arrays, and review those later. 567 */ 568 if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) { 569 disk = ndisk; 570 slot = nslot; 571 break; 572 } 573 574 /* for far > 1 always use the lowest address */ 575 if (conf->far_copies > 1) 576 new_distance = r10_bio->devs[nslot].addr; 577 else 578 new_distance = abs(r10_bio->devs[nslot].addr - 579 conf->mirrors[ndisk].head_position); 580 if (new_distance < current_distance) { 581 current_distance = new_distance; 582 disk = ndisk; 583 slot = nslot; 584 } 585 } 586 587 rb_out: 588 r10_bio->read_slot = slot; 589 /* conf->next_seq_sect = this_sector + sectors;*/ 590 591 if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL) 592 atomic_inc(&conf->mirrors[disk].rdev->nr_pending); 593 else 594 disk = -1; 595 rcu_read_unlock(); 596 597 return disk; 598 } 599 600 static void unplug_slaves(mddev_t *mddev) 601 { 602 conf_t *conf = mddev->private; 603 int i; 604 605 rcu_read_lock(); 606 for (i=0; i < conf->raid_disks; i++) { 607 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 608 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 609 struct request_queue *r_queue = bdev_get_queue(rdev->bdev); 610 611 atomic_inc(&rdev->nr_pending); 612 rcu_read_unlock(); 613 614 blk_unplug(r_queue); 615 616 rdev_dec_pending(rdev, mddev); 617 rcu_read_lock(); 618 } 619 } 620 rcu_read_unlock(); 621 } 622 623 static void raid10_unplug(struct request_queue *q) 624 { 625 mddev_t *mddev = q->queuedata; 626 627 unplug_slaves(q->queuedata); 628 md_wakeup_thread(mddev->thread); 629 } 630 631 static int raid10_congested(void *data, int bits) 632 { 633 mddev_t *mddev = data; 634 conf_t *conf = mddev->private; 635 int i, ret = 0; 636 637 if (mddev_congested(mddev, bits)) 638 return 1; 639 rcu_read_lock(); 640 for (i = 0; i < conf->raid_disks && ret == 0; i++) { 641 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); 642 if (rdev && !test_bit(Faulty, &rdev->flags)) { 643 struct request_queue *q = bdev_get_queue(rdev->bdev); 644 645 ret |= bdi_congested(&q->backing_dev_info, bits); 646 } 647 } 648 rcu_read_unlock(); 649 return ret; 650 } 651 652 static int flush_pending_writes(conf_t *conf) 653 { 654 /* Any writes that have been queued but are awaiting 655 * bitmap updates get flushed here. 656 * We return 1 if any requests were actually submitted. 657 */ 658 int rv = 0; 659 660 spin_lock_irq(&conf->device_lock); 661 662 if (conf->pending_bio_list.head) { 663 struct bio *bio; 664 bio = bio_list_get(&conf->pending_bio_list); 665 blk_remove_plug(conf->mddev->queue); 666 spin_unlock_irq(&conf->device_lock); 667 /* flush any pending bitmap writes to disk 668 * before proceeding w/ I/O */ 669 bitmap_unplug(conf->mddev->bitmap); 670 671 while (bio) { /* submit pending writes */ 672 struct bio *next = bio->bi_next; 673 bio->bi_next = NULL; 674 generic_make_request(bio); 675 bio = next; 676 } 677 rv = 1; 678 } else 679 spin_unlock_irq(&conf->device_lock); 680 return rv; 681 } 682 /* Barriers.... 683 * Sometimes we need to suspend IO while we do something else, 684 * either some resync/recovery, or reconfigure the array. 685 * To do this we raise a 'barrier'. 686 * The 'barrier' is a counter that can be raised multiple times 687 * to count how many activities are happening which preclude 688 * normal IO. 689 * We can only raise the barrier if there is no pending IO. 690 * i.e. if nr_pending == 0. 691 * We choose only to raise the barrier if no-one is waiting for the 692 * barrier to go down. This means that as soon as an IO request 693 * is ready, no other operations which require a barrier will start 694 * until the IO request has had a chance. 695 * 696 * So: regular IO calls 'wait_barrier'. When that returns there 697 * is no backgroup IO happening, It must arrange to call 698 * allow_barrier when it has finished its IO. 699 * backgroup IO calls must call raise_barrier. Once that returns 700 * there is no normal IO happeing. It must arrange to call 701 * lower_barrier when the particular background IO completes. 702 */ 703 704 static void raise_barrier(conf_t *conf, int force) 705 { 706 BUG_ON(force && !conf->barrier); 707 spin_lock_irq(&conf->resync_lock); 708 709 /* Wait until no block IO is waiting (unless 'force') */ 710 wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, 711 conf->resync_lock, 712 raid10_unplug(conf->mddev->queue)); 713 714 /* block any new IO from starting */ 715 conf->barrier++; 716 717 /* No wait for all pending IO to complete */ 718 wait_event_lock_irq(conf->wait_barrier, 719 !conf->nr_pending && conf->barrier < RESYNC_DEPTH, 720 conf->resync_lock, 721 raid10_unplug(conf->mddev->queue)); 722 723 spin_unlock_irq(&conf->resync_lock); 724 } 725 726 static void lower_barrier(conf_t *conf) 727 { 728 unsigned long flags; 729 spin_lock_irqsave(&conf->resync_lock, flags); 730 conf->barrier--; 731 spin_unlock_irqrestore(&conf->resync_lock, flags); 732 wake_up(&conf->wait_barrier); 733 } 734 735 static void wait_barrier(conf_t *conf) 736 { 737 spin_lock_irq(&conf->resync_lock); 738 if (conf->barrier) { 739 conf->nr_waiting++; 740 wait_event_lock_irq(conf->wait_barrier, !conf->barrier, 741 conf->resync_lock, 742 raid10_unplug(conf->mddev->queue)); 743 conf->nr_waiting--; 744 } 745 conf->nr_pending++; 746 spin_unlock_irq(&conf->resync_lock); 747 } 748 749 static void allow_barrier(conf_t *conf) 750 { 751 unsigned long flags; 752 spin_lock_irqsave(&conf->resync_lock, flags); 753 conf->nr_pending--; 754 spin_unlock_irqrestore(&conf->resync_lock, flags); 755 wake_up(&conf->wait_barrier); 756 } 757 758 static void freeze_array(conf_t *conf) 759 { 760 /* stop syncio and normal IO and wait for everything to 761 * go quiet. 762 * We increment barrier and nr_waiting, and then 763 * wait until nr_pending match nr_queued+1 764 * This is called in the context of one normal IO request 765 * that has failed. Thus any sync request that might be pending 766 * will be blocked by nr_pending, and we need to wait for 767 * pending IO requests to complete or be queued for re-try. 768 * Thus the number queued (nr_queued) plus this request (1) 769 * must match the number of pending IOs (nr_pending) before 770 * we continue. 771 */ 772 spin_lock_irq(&conf->resync_lock); 773 conf->barrier++; 774 conf->nr_waiting++; 775 wait_event_lock_irq(conf->wait_barrier, 776 conf->nr_pending == conf->nr_queued+1, 777 conf->resync_lock, 778 ({ flush_pending_writes(conf); 779 raid10_unplug(conf->mddev->queue); })); 780 spin_unlock_irq(&conf->resync_lock); 781 } 782 783 static void unfreeze_array(conf_t *conf) 784 { 785 /* reverse the effect of the freeze */ 786 spin_lock_irq(&conf->resync_lock); 787 conf->barrier--; 788 conf->nr_waiting--; 789 wake_up(&conf->wait_barrier); 790 spin_unlock_irq(&conf->resync_lock); 791 } 792 793 static int make_request(mddev_t *mddev, struct bio * bio) 794 { 795 conf_t *conf = mddev->private; 796 mirror_info_t *mirror; 797 r10bio_t *r10_bio; 798 struct bio *read_bio; 799 int i; 800 int chunk_sects = conf->chunk_mask + 1; 801 const int rw = bio_data_dir(bio); 802 const unsigned long do_sync = (bio->bi_rw & REQ_SYNC); 803 struct bio_list bl; 804 unsigned long flags; 805 mdk_rdev_t *blocked_rdev; 806 807 if (unlikely(bio->bi_rw & REQ_HARDBARRIER)) { 808 md_barrier_request(mddev, bio); 809 return 0; 810 } 811 812 /* If this request crosses a chunk boundary, we need to 813 * split it. This will only happen for 1 PAGE (or less) requests. 814 */ 815 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) 816 > chunk_sects && 817 conf->near_copies < conf->raid_disks)) { 818 struct bio_pair *bp; 819 /* Sanity check -- queue functions should prevent this happening */ 820 if (bio->bi_vcnt != 1 || 821 bio->bi_idx != 0) 822 goto bad_map; 823 /* This is a one page bio that upper layers 824 * refuse to split for us, so we need to split it. 825 */ 826 bp = bio_split(bio, 827 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); 828 829 /* Each of these 'make_request' calls will call 'wait_barrier'. 830 * If the first succeeds but the second blocks due to the resync 831 * thread raising the barrier, we will deadlock because the 832 * IO to the underlying device will be queued in generic_make_request 833 * and will never complete, so will never reduce nr_pending. 834 * So increment nr_waiting here so no new raise_barriers will 835 * succeed, and so the second wait_barrier cannot block. 836 */ 837 spin_lock_irq(&conf->resync_lock); 838 conf->nr_waiting++; 839 spin_unlock_irq(&conf->resync_lock); 840 841 if (make_request(mddev, &bp->bio1)) 842 generic_make_request(&bp->bio1); 843 if (make_request(mddev, &bp->bio2)) 844 generic_make_request(&bp->bio2); 845 846 spin_lock_irq(&conf->resync_lock); 847 conf->nr_waiting--; 848 wake_up(&conf->wait_barrier); 849 spin_unlock_irq(&conf->resync_lock); 850 851 bio_pair_release(bp); 852 return 0; 853 bad_map: 854 printk("md/raid10:%s: make_request bug: can't convert block across chunks" 855 " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2, 856 (unsigned long long)bio->bi_sector, bio->bi_size >> 10); 857 858 bio_io_error(bio); 859 return 0; 860 } 861 862 md_write_start(mddev, bio); 863 864 /* 865 * Register the new request and wait if the reconstruction 866 * thread has put up a bar for new requests. 867 * Continue immediately if no resync is active currently. 868 */ 869 wait_barrier(conf); 870 871 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); 872 873 r10_bio->master_bio = bio; 874 r10_bio->sectors = bio->bi_size >> 9; 875 876 r10_bio->mddev = mddev; 877 r10_bio->sector = bio->bi_sector; 878 r10_bio->state = 0; 879 880 if (rw == READ) { 881 /* 882 * read balancing logic: 883 */ 884 int disk = read_balance(conf, r10_bio); 885 int slot = r10_bio->read_slot; 886 if (disk < 0) { 887 raid_end_bio_io(r10_bio); 888 return 0; 889 } 890 mirror = conf->mirrors + disk; 891 892 read_bio = bio_clone(bio, GFP_NOIO); 893 894 r10_bio->devs[slot].bio = read_bio; 895 896 read_bio->bi_sector = r10_bio->devs[slot].addr + 897 mirror->rdev->data_offset; 898 read_bio->bi_bdev = mirror->rdev->bdev; 899 read_bio->bi_end_io = raid10_end_read_request; 900 read_bio->bi_rw = READ | do_sync; 901 read_bio->bi_private = r10_bio; 902 903 generic_make_request(read_bio); 904 return 0; 905 } 906 907 /* 908 * WRITE: 909 */ 910 /* first select target devices under rcu_lock and 911 * inc refcount on their rdev. Record them by setting 912 * bios[x] to bio 913 */ 914 raid10_find_phys(conf, r10_bio); 915 retry_write: 916 blocked_rdev = NULL; 917 rcu_read_lock(); 918 for (i = 0; i < conf->copies; i++) { 919 int d = r10_bio->devs[i].devnum; 920 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev); 921 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 922 atomic_inc(&rdev->nr_pending); 923 blocked_rdev = rdev; 924 break; 925 } 926 if (rdev && !test_bit(Faulty, &rdev->flags)) { 927 atomic_inc(&rdev->nr_pending); 928 r10_bio->devs[i].bio = bio; 929 } else { 930 r10_bio->devs[i].bio = NULL; 931 set_bit(R10BIO_Degraded, &r10_bio->state); 932 } 933 } 934 rcu_read_unlock(); 935 936 if (unlikely(blocked_rdev)) { 937 /* Have to wait for this device to get unblocked, then retry */ 938 int j; 939 int d; 940 941 for (j = 0; j < i; j++) 942 if (r10_bio->devs[j].bio) { 943 d = r10_bio->devs[j].devnum; 944 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 945 } 946 allow_barrier(conf); 947 md_wait_for_blocked_rdev(blocked_rdev, mddev); 948 wait_barrier(conf); 949 goto retry_write; 950 } 951 952 atomic_set(&r10_bio->remaining, 0); 953 954 bio_list_init(&bl); 955 for (i = 0; i < conf->copies; i++) { 956 struct bio *mbio; 957 int d = r10_bio->devs[i].devnum; 958 if (!r10_bio->devs[i].bio) 959 continue; 960 961 mbio = bio_clone(bio, GFP_NOIO); 962 r10_bio->devs[i].bio = mbio; 963 964 mbio->bi_sector = r10_bio->devs[i].addr+ 965 conf->mirrors[d].rdev->data_offset; 966 mbio->bi_bdev = conf->mirrors[d].rdev->bdev; 967 mbio->bi_end_io = raid10_end_write_request; 968 mbio->bi_rw = WRITE | do_sync; 969 mbio->bi_private = r10_bio; 970 971 atomic_inc(&r10_bio->remaining); 972 bio_list_add(&bl, mbio); 973 } 974 975 if (unlikely(!atomic_read(&r10_bio->remaining))) { 976 /* the array is dead */ 977 md_write_end(mddev); 978 raid_end_bio_io(r10_bio); 979 return 0; 980 } 981 982 bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0); 983 spin_lock_irqsave(&conf->device_lock, flags); 984 bio_list_merge(&conf->pending_bio_list, &bl); 985 blk_plug_device(mddev->queue); 986 spin_unlock_irqrestore(&conf->device_lock, flags); 987 988 /* In case raid10d snuck in to freeze_array */ 989 wake_up(&conf->wait_barrier); 990 991 if (do_sync) 992 md_wakeup_thread(mddev->thread); 993 994 return 0; 995 } 996 997 static void status(struct seq_file *seq, mddev_t *mddev) 998 { 999 conf_t *conf = mddev->private; 1000 int i; 1001 1002 if (conf->near_copies < conf->raid_disks) 1003 seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2); 1004 if (conf->near_copies > 1) 1005 seq_printf(seq, " %d near-copies", conf->near_copies); 1006 if (conf->far_copies > 1) { 1007 if (conf->far_offset) 1008 seq_printf(seq, " %d offset-copies", conf->far_copies); 1009 else 1010 seq_printf(seq, " %d far-copies", conf->far_copies); 1011 } 1012 seq_printf(seq, " [%d/%d] [", conf->raid_disks, 1013 conf->raid_disks - mddev->degraded); 1014 for (i = 0; i < conf->raid_disks; i++) 1015 seq_printf(seq, "%s", 1016 conf->mirrors[i].rdev && 1017 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_"); 1018 seq_printf(seq, "]"); 1019 } 1020 1021 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 1022 { 1023 char b[BDEVNAME_SIZE]; 1024 conf_t *conf = mddev->private; 1025 1026 /* 1027 * If it is not operational, then we have already marked it as dead 1028 * else if it is the last working disks, ignore the error, let the 1029 * next level up know. 1030 * else mark the drive as failed 1031 */ 1032 if (test_bit(In_sync, &rdev->flags) 1033 && conf->raid_disks-mddev->degraded == 1) 1034 /* 1035 * Don't fail the drive, just return an IO error. 1036 * The test should really be more sophisticated than 1037 * "working_disks == 1", but it isn't critical, and 1038 * can wait until we do more sophisticated "is the drive 1039 * really dead" tests... 1040 */ 1041 return; 1042 if (test_and_clear_bit(In_sync, &rdev->flags)) { 1043 unsigned long flags; 1044 spin_lock_irqsave(&conf->device_lock, flags); 1045 mddev->degraded++; 1046 spin_unlock_irqrestore(&conf->device_lock, flags); 1047 /* 1048 * if recovery is running, make sure it aborts. 1049 */ 1050 set_bit(MD_RECOVERY_INTR, &mddev->recovery); 1051 } 1052 set_bit(Faulty, &rdev->flags); 1053 set_bit(MD_CHANGE_DEVS, &mddev->flags); 1054 printk(KERN_ALERT "md/raid10:%s: Disk failure on %s, disabling device.\n" 1055 KERN_ALERT "md/raid10:%s: Operation continuing on %d devices.\n", 1056 mdname(mddev), bdevname(rdev->bdev, b), 1057 mdname(mddev), conf->raid_disks - mddev->degraded); 1058 } 1059 1060 static void print_conf(conf_t *conf) 1061 { 1062 int i; 1063 mirror_info_t *tmp; 1064 1065 printk(KERN_DEBUG "RAID10 conf printout:\n"); 1066 if (!conf) { 1067 printk(KERN_DEBUG "(!conf)\n"); 1068 return; 1069 } 1070 printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, 1071 conf->raid_disks); 1072 1073 for (i = 0; i < conf->raid_disks; i++) { 1074 char b[BDEVNAME_SIZE]; 1075 tmp = conf->mirrors + i; 1076 if (tmp->rdev) 1077 printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n", 1078 i, !test_bit(In_sync, &tmp->rdev->flags), 1079 !test_bit(Faulty, &tmp->rdev->flags), 1080 bdevname(tmp->rdev->bdev,b)); 1081 } 1082 } 1083 1084 static void close_sync(conf_t *conf) 1085 { 1086 wait_barrier(conf); 1087 allow_barrier(conf); 1088 1089 mempool_destroy(conf->r10buf_pool); 1090 conf->r10buf_pool = NULL; 1091 } 1092 1093 /* check if there are enough drives for 1094 * every block to appear on atleast one 1095 */ 1096 static int enough(conf_t *conf) 1097 { 1098 int first = 0; 1099 1100 do { 1101 int n = conf->copies; 1102 int cnt = 0; 1103 while (n--) { 1104 if (conf->mirrors[first].rdev) 1105 cnt++; 1106 first = (first+1) % conf->raid_disks; 1107 } 1108 if (cnt == 0) 1109 return 0; 1110 } while (first != 0); 1111 return 1; 1112 } 1113 1114 static int raid10_spare_active(mddev_t *mddev) 1115 { 1116 int i; 1117 conf_t *conf = mddev->private; 1118 mirror_info_t *tmp; 1119 int count = 0; 1120 unsigned long flags; 1121 1122 /* 1123 * Find all non-in_sync disks within the RAID10 configuration 1124 * and mark them in_sync 1125 */ 1126 for (i = 0; i < conf->raid_disks; i++) { 1127 tmp = conf->mirrors + i; 1128 if (tmp->rdev 1129 && !test_bit(Faulty, &tmp->rdev->flags) 1130 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 1131 count++; 1132 sysfs_notify_dirent(tmp->rdev->sysfs_state); 1133 } 1134 } 1135 spin_lock_irqsave(&conf->device_lock, flags); 1136 mddev->degraded -= count; 1137 spin_unlock_irqrestore(&conf->device_lock, flags); 1138 1139 print_conf(conf); 1140 return count; 1141 } 1142 1143 1144 static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 1145 { 1146 conf_t *conf = mddev->private; 1147 int err = -EEXIST; 1148 int mirror; 1149 mirror_info_t *p; 1150 int first = 0; 1151 int last = conf->raid_disks - 1; 1152 1153 if (mddev->recovery_cp < MaxSector) 1154 /* only hot-add to in-sync arrays, as recovery is 1155 * very different from resync 1156 */ 1157 return -EBUSY; 1158 if (!enough(conf)) 1159 return -EINVAL; 1160 1161 if (rdev->raid_disk >= 0) 1162 first = last = rdev->raid_disk; 1163 1164 if (rdev->saved_raid_disk >= 0 && 1165 rdev->saved_raid_disk >= first && 1166 conf->mirrors[rdev->saved_raid_disk].rdev == NULL) 1167 mirror = rdev->saved_raid_disk; 1168 else 1169 mirror = first; 1170 for ( ; mirror <= last ; mirror++) 1171 if ( !(p=conf->mirrors+mirror)->rdev) { 1172 1173 disk_stack_limits(mddev->gendisk, rdev->bdev, 1174 rdev->data_offset << 9); 1175 /* as we don't honour merge_bvec_fn, we must 1176 * never risk violating it, so limit 1177 * ->max_segments to one lying with a single 1178 * page, as a one page request is never in 1179 * violation. 1180 */ 1181 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { 1182 blk_queue_max_segments(mddev->queue, 1); 1183 blk_queue_segment_boundary(mddev->queue, 1184 PAGE_CACHE_SIZE - 1); 1185 } 1186 1187 p->head_position = 0; 1188 rdev->raid_disk = mirror; 1189 err = 0; 1190 if (rdev->saved_raid_disk != mirror) 1191 conf->fullsync = 1; 1192 rcu_assign_pointer(p->rdev, rdev); 1193 break; 1194 } 1195 1196 md_integrity_add_rdev(rdev, mddev); 1197 print_conf(conf); 1198 return err; 1199 } 1200 1201 static int raid10_remove_disk(mddev_t *mddev, int number) 1202 { 1203 conf_t *conf = mddev->private; 1204 int err = 0; 1205 mdk_rdev_t *rdev; 1206 mirror_info_t *p = conf->mirrors+ number; 1207 1208 print_conf(conf); 1209 rdev = p->rdev; 1210 if (rdev) { 1211 if (test_bit(In_sync, &rdev->flags) || 1212 atomic_read(&rdev->nr_pending)) { 1213 err = -EBUSY; 1214 goto abort; 1215 } 1216 /* Only remove faulty devices in recovery 1217 * is not possible. 1218 */ 1219 if (!test_bit(Faulty, &rdev->flags) && 1220 enough(conf)) { 1221 err = -EBUSY; 1222 goto abort; 1223 } 1224 p->rdev = NULL; 1225 synchronize_rcu(); 1226 if (atomic_read(&rdev->nr_pending)) { 1227 /* lost the race, try later */ 1228 err = -EBUSY; 1229 p->rdev = rdev; 1230 goto abort; 1231 } 1232 md_integrity_register(mddev); 1233 } 1234 abort: 1235 1236 print_conf(conf); 1237 return err; 1238 } 1239 1240 1241 static void end_sync_read(struct bio *bio, int error) 1242 { 1243 r10bio_t *r10_bio = bio->bi_private; 1244 conf_t *conf = r10_bio->mddev->private; 1245 int i,d; 1246 1247 for (i=0; i<conf->copies; i++) 1248 if (r10_bio->devs[i].bio == bio) 1249 break; 1250 BUG_ON(i == conf->copies); 1251 update_head_pos(i, r10_bio); 1252 d = r10_bio->devs[i].devnum; 1253 1254 if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 1255 set_bit(R10BIO_Uptodate, &r10_bio->state); 1256 else { 1257 atomic_add(r10_bio->sectors, 1258 &conf->mirrors[d].rdev->corrected_errors); 1259 if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) 1260 md_error(r10_bio->mddev, 1261 conf->mirrors[d].rdev); 1262 } 1263 1264 /* for reconstruct, we always reschedule after a read. 1265 * for resync, only after all reads 1266 */ 1267 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); 1268 if (test_bit(R10BIO_IsRecover, &r10_bio->state) || 1269 atomic_dec_and_test(&r10_bio->remaining)) { 1270 /* we have read all the blocks, 1271 * do the comparison in process context in raid10d 1272 */ 1273 reschedule_retry(r10_bio); 1274 } 1275 } 1276 1277 static void end_sync_write(struct bio *bio, int error) 1278 { 1279 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 1280 r10bio_t *r10_bio = bio->bi_private; 1281 mddev_t *mddev = r10_bio->mddev; 1282 conf_t *conf = mddev->private; 1283 int i,d; 1284 1285 for (i = 0; i < conf->copies; i++) 1286 if (r10_bio->devs[i].bio == bio) 1287 break; 1288 d = r10_bio->devs[i].devnum; 1289 1290 if (!uptodate) 1291 md_error(mddev, conf->mirrors[d].rdev); 1292 1293 update_head_pos(i, r10_bio); 1294 1295 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 1296 while (atomic_dec_and_test(&r10_bio->remaining)) { 1297 if (r10_bio->master_bio == NULL) { 1298 /* the primary of several recovery bios */ 1299 sector_t s = r10_bio->sectors; 1300 put_buf(r10_bio); 1301 md_done_sync(mddev, s, 1); 1302 break; 1303 } else { 1304 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; 1305 put_buf(r10_bio); 1306 r10_bio = r10_bio2; 1307 } 1308 } 1309 } 1310 1311 /* 1312 * Note: sync and recover and handled very differently for raid10 1313 * This code is for resync. 1314 * For resync, we read through virtual addresses and read all blocks. 1315 * If there is any error, we schedule a write. The lowest numbered 1316 * drive is authoritative. 1317 * However requests come for physical address, so we need to map. 1318 * For every physical address there are raid_disks/copies virtual addresses, 1319 * which is always are least one, but is not necessarly an integer. 1320 * This means that a physical address can span multiple chunks, so we may 1321 * have to submit multiple io requests for a single sync request. 1322 */ 1323 /* 1324 * We check if all blocks are in-sync and only write to blocks that 1325 * aren't in sync 1326 */ 1327 static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) 1328 { 1329 conf_t *conf = mddev->private; 1330 int i, first; 1331 struct bio *tbio, *fbio; 1332 1333 atomic_set(&r10_bio->remaining, 1); 1334 1335 /* find the first device with a block */ 1336 for (i=0; i<conf->copies; i++) 1337 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) 1338 break; 1339 1340 if (i == conf->copies) 1341 goto done; 1342 1343 first = i; 1344 fbio = r10_bio->devs[i].bio; 1345 1346 /* now find blocks with errors */ 1347 for (i=0 ; i < conf->copies ; i++) { 1348 int j, d; 1349 int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); 1350 1351 tbio = r10_bio->devs[i].bio; 1352 1353 if (tbio->bi_end_io != end_sync_read) 1354 continue; 1355 if (i == first) 1356 continue; 1357 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) { 1358 /* We know that the bi_io_vec layout is the same for 1359 * both 'first' and 'i', so we just compare them. 1360 * All vec entries are PAGE_SIZE; 1361 */ 1362 for (j = 0; j < vcnt; j++) 1363 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), 1364 page_address(tbio->bi_io_vec[j].bv_page), 1365 PAGE_SIZE)) 1366 break; 1367 if (j == vcnt) 1368 continue; 1369 mddev->resync_mismatches += r10_bio->sectors; 1370 } 1371 if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) 1372 /* Don't fix anything. */ 1373 continue; 1374 /* Ok, we need to write this bio 1375 * First we need to fixup bv_offset, bv_len and 1376 * bi_vecs, as the read request might have corrupted these 1377 */ 1378 tbio->bi_vcnt = vcnt; 1379 tbio->bi_size = r10_bio->sectors << 9; 1380 tbio->bi_idx = 0; 1381 tbio->bi_phys_segments = 0; 1382 tbio->bi_flags &= ~(BIO_POOL_MASK - 1); 1383 tbio->bi_flags |= 1 << BIO_UPTODATE; 1384 tbio->bi_next = NULL; 1385 tbio->bi_rw = WRITE; 1386 tbio->bi_private = r10_bio; 1387 tbio->bi_sector = r10_bio->devs[i].addr; 1388 1389 for (j=0; j < vcnt ; j++) { 1390 tbio->bi_io_vec[j].bv_offset = 0; 1391 tbio->bi_io_vec[j].bv_len = PAGE_SIZE; 1392 1393 memcpy(page_address(tbio->bi_io_vec[j].bv_page), 1394 page_address(fbio->bi_io_vec[j].bv_page), 1395 PAGE_SIZE); 1396 } 1397 tbio->bi_end_io = end_sync_write; 1398 1399 d = r10_bio->devs[i].devnum; 1400 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1401 atomic_inc(&r10_bio->remaining); 1402 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); 1403 1404 tbio->bi_sector += conf->mirrors[d].rdev->data_offset; 1405 tbio->bi_bdev = conf->mirrors[d].rdev->bdev; 1406 generic_make_request(tbio); 1407 } 1408 1409 done: 1410 if (atomic_dec_and_test(&r10_bio->remaining)) { 1411 md_done_sync(mddev, r10_bio->sectors, 1); 1412 put_buf(r10_bio); 1413 } 1414 } 1415 1416 /* 1417 * Now for the recovery code. 1418 * Recovery happens across physical sectors. 1419 * We recover all non-is_sync drives by finding the virtual address of 1420 * each, and then choose a working drive that also has that virt address. 1421 * There is a separate r10_bio for each non-in_sync drive. 1422 * Only the first two slots are in use. The first for reading, 1423 * The second for writing. 1424 * 1425 */ 1426 1427 static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) 1428 { 1429 conf_t *conf = mddev->private; 1430 int i, d; 1431 struct bio *bio, *wbio; 1432 1433 1434 /* move the pages across to the second bio 1435 * and submit the write request 1436 */ 1437 bio = r10_bio->devs[0].bio; 1438 wbio = r10_bio->devs[1].bio; 1439 for (i=0; i < wbio->bi_vcnt; i++) { 1440 struct page *p = bio->bi_io_vec[i].bv_page; 1441 bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; 1442 wbio->bi_io_vec[i].bv_page = p; 1443 } 1444 d = r10_bio->devs[1].devnum; 1445 1446 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1447 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); 1448 if (test_bit(R10BIO_Uptodate, &r10_bio->state)) 1449 generic_make_request(wbio); 1450 else 1451 bio_endio(wbio, -EIO); 1452 } 1453 1454 1455 /* 1456 * Used by fix_read_error() to decay the per rdev read_errors. 1457 * We halve the read error count for every hour that has elapsed 1458 * since the last recorded read error. 1459 * 1460 */ 1461 static void check_decay_read_errors(mddev_t *mddev, mdk_rdev_t *rdev) 1462 { 1463 struct timespec cur_time_mon; 1464 unsigned long hours_since_last; 1465 unsigned int read_errors = atomic_read(&rdev->read_errors); 1466 1467 ktime_get_ts(&cur_time_mon); 1468 1469 if (rdev->last_read_error.tv_sec == 0 && 1470 rdev->last_read_error.tv_nsec == 0) { 1471 /* first time we've seen a read error */ 1472 rdev->last_read_error = cur_time_mon; 1473 return; 1474 } 1475 1476 hours_since_last = (cur_time_mon.tv_sec - 1477 rdev->last_read_error.tv_sec) / 3600; 1478 1479 rdev->last_read_error = cur_time_mon; 1480 1481 /* 1482 * if hours_since_last is > the number of bits in read_errors 1483 * just set read errors to 0. We do this to avoid 1484 * overflowing the shift of read_errors by hours_since_last. 1485 */ 1486 if (hours_since_last >= 8 * sizeof(read_errors)) 1487 atomic_set(&rdev->read_errors, 0); 1488 else 1489 atomic_set(&rdev->read_errors, read_errors >> hours_since_last); 1490 } 1491 1492 /* 1493 * This is a kernel thread which: 1494 * 1495 * 1. Retries failed read operations on working mirrors. 1496 * 2. Updates the raid superblock when problems encounter. 1497 * 3. Performs writes following reads for array synchronising. 1498 */ 1499 1500 static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) 1501 { 1502 int sect = 0; /* Offset from r10_bio->sector */ 1503 int sectors = r10_bio->sectors; 1504 mdk_rdev_t*rdev; 1505 int max_read_errors = atomic_read(&mddev->max_corr_read_errors); 1506 int d = r10_bio->devs[r10_bio->read_slot].devnum; 1507 1508 rcu_read_lock(); 1509 rdev = rcu_dereference(conf->mirrors[d].rdev); 1510 if (rdev) { /* If rdev is not NULL */ 1511 char b[BDEVNAME_SIZE]; 1512 int cur_read_error_count = 0; 1513 1514 bdevname(rdev->bdev, b); 1515 1516 if (test_bit(Faulty, &rdev->flags)) { 1517 rcu_read_unlock(); 1518 /* drive has already been failed, just ignore any 1519 more fix_read_error() attempts */ 1520 return; 1521 } 1522 1523 check_decay_read_errors(mddev, rdev); 1524 atomic_inc(&rdev->read_errors); 1525 cur_read_error_count = atomic_read(&rdev->read_errors); 1526 if (cur_read_error_count > max_read_errors) { 1527 rcu_read_unlock(); 1528 printk(KERN_NOTICE 1529 "md/raid10:%s: %s: Raid device exceeded " 1530 "read_error threshold " 1531 "[cur %d:max %d]\n", 1532 mdname(mddev), 1533 b, cur_read_error_count, max_read_errors); 1534 printk(KERN_NOTICE 1535 "md/raid10:%s: %s: Failing raid " 1536 "device\n", mdname(mddev), b); 1537 md_error(mddev, conf->mirrors[d].rdev); 1538 return; 1539 } 1540 } 1541 rcu_read_unlock(); 1542 1543 while(sectors) { 1544 int s = sectors; 1545 int sl = r10_bio->read_slot; 1546 int success = 0; 1547 int start; 1548 1549 if (s > (PAGE_SIZE>>9)) 1550 s = PAGE_SIZE >> 9; 1551 1552 rcu_read_lock(); 1553 do { 1554 d = r10_bio->devs[sl].devnum; 1555 rdev = rcu_dereference(conf->mirrors[d].rdev); 1556 if (rdev && 1557 test_bit(In_sync, &rdev->flags)) { 1558 atomic_inc(&rdev->nr_pending); 1559 rcu_read_unlock(); 1560 success = sync_page_io(rdev->bdev, 1561 r10_bio->devs[sl].addr + 1562 sect + rdev->data_offset, 1563 s<<9, 1564 conf->tmppage, READ); 1565 rdev_dec_pending(rdev, mddev); 1566 rcu_read_lock(); 1567 if (success) 1568 break; 1569 } 1570 sl++; 1571 if (sl == conf->copies) 1572 sl = 0; 1573 } while (!success && sl != r10_bio->read_slot); 1574 rcu_read_unlock(); 1575 1576 if (!success) { 1577 /* Cannot read from anywhere -- bye bye array */ 1578 int dn = r10_bio->devs[r10_bio->read_slot].devnum; 1579 md_error(mddev, conf->mirrors[dn].rdev); 1580 break; 1581 } 1582 1583 start = sl; 1584 /* write it back and re-read */ 1585 rcu_read_lock(); 1586 while (sl != r10_bio->read_slot) { 1587 char b[BDEVNAME_SIZE]; 1588 1589 if (sl==0) 1590 sl = conf->copies; 1591 sl--; 1592 d = r10_bio->devs[sl].devnum; 1593 rdev = rcu_dereference(conf->mirrors[d].rdev); 1594 if (rdev && 1595 test_bit(In_sync, &rdev->flags)) { 1596 atomic_inc(&rdev->nr_pending); 1597 rcu_read_unlock(); 1598 atomic_add(s, &rdev->corrected_errors); 1599 if (sync_page_io(rdev->bdev, 1600 r10_bio->devs[sl].addr + 1601 sect + rdev->data_offset, 1602 s<<9, conf->tmppage, WRITE) 1603 == 0) { 1604 /* Well, this device is dead */ 1605 printk(KERN_NOTICE 1606 "md/raid10:%s: read correction " 1607 "write failed" 1608 " (%d sectors at %llu on %s)\n", 1609 mdname(mddev), s, 1610 (unsigned long long)(sect+ 1611 rdev->data_offset), 1612 bdevname(rdev->bdev, b)); 1613 printk(KERN_NOTICE "md/raid10:%s: %s: failing " 1614 "drive\n", 1615 mdname(mddev), 1616 bdevname(rdev->bdev, b)); 1617 md_error(mddev, rdev); 1618 } 1619 rdev_dec_pending(rdev, mddev); 1620 rcu_read_lock(); 1621 } 1622 } 1623 sl = start; 1624 while (sl != r10_bio->read_slot) { 1625 1626 if (sl==0) 1627 sl = conf->copies; 1628 sl--; 1629 d = r10_bio->devs[sl].devnum; 1630 rdev = rcu_dereference(conf->mirrors[d].rdev); 1631 if (rdev && 1632 test_bit(In_sync, &rdev->flags)) { 1633 char b[BDEVNAME_SIZE]; 1634 atomic_inc(&rdev->nr_pending); 1635 rcu_read_unlock(); 1636 if (sync_page_io(rdev->bdev, 1637 r10_bio->devs[sl].addr + 1638 sect + rdev->data_offset, 1639 s<<9, conf->tmppage, 1640 READ) == 0) { 1641 /* Well, this device is dead */ 1642 printk(KERN_NOTICE 1643 "md/raid10:%s: unable to read back " 1644 "corrected sectors" 1645 " (%d sectors at %llu on %s)\n", 1646 mdname(mddev), s, 1647 (unsigned long long)(sect+ 1648 rdev->data_offset), 1649 bdevname(rdev->bdev, b)); 1650 printk(KERN_NOTICE "md/raid10:%s: %s: failing drive\n", 1651 mdname(mddev), 1652 bdevname(rdev->bdev, b)); 1653 1654 md_error(mddev, rdev); 1655 } else { 1656 printk(KERN_INFO 1657 "md/raid10:%s: read error corrected" 1658 " (%d sectors at %llu on %s)\n", 1659 mdname(mddev), s, 1660 (unsigned long long)(sect+ 1661 rdev->data_offset), 1662 bdevname(rdev->bdev, b)); 1663 } 1664 1665 rdev_dec_pending(rdev, mddev); 1666 rcu_read_lock(); 1667 } 1668 } 1669 rcu_read_unlock(); 1670 1671 sectors -= s; 1672 sect += s; 1673 } 1674 } 1675 1676 static void raid10d(mddev_t *mddev) 1677 { 1678 r10bio_t *r10_bio; 1679 struct bio *bio; 1680 unsigned long flags; 1681 conf_t *conf = mddev->private; 1682 struct list_head *head = &conf->retry_list; 1683 int unplug=0; 1684 mdk_rdev_t *rdev; 1685 1686 md_check_recovery(mddev); 1687 1688 for (;;) { 1689 char b[BDEVNAME_SIZE]; 1690 1691 unplug += flush_pending_writes(conf); 1692 1693 spin_lock_irqsave(&conf->device_lock, flags); 1694 if (list_empty(head)) { 1695 spin_unlock_irqrestore(&conf->device_lock, flags); 1696 break; 1697 } 1698 r10_bio = list_entry(head->prev, r10bio_t, retry_list); 1699 list_del(head->prev); 1700 conf->nr_queued--; 1701 spin_unlock_irqrestore(&conf->device_lock, flags); 1702 1703 mddev = r10_bio->mddev; 1704 conf = mddev->private; 1705 if (test_bit(R10BIO_IsSync, &r10_bio->state)) { 1706 sync_request_write(mddev, r10_bio); 1707 unplug = 1; 1708 } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { 1709 recovery_request_write(mddev, r10_bio); 1710 unplug = 1; 1711 } else { 1712 int mirror; 1713 /* we got a read error. Maybe the drive is bad. Maybe just 1714 * the block and we can fix it. 1715 * We freeze all other IO, and try reading the block from 1716 * other devices. When we find one, we re-write 1717 * and check it that fixes the read error. 1718 * This is all done synchronously while the array is 1719 * frozen. 1720 */ 1721 if (mddev->ro == 0) { 1722 freeze_array(conf); 1723 fix_read_error(conf, mddev, r10_bio); 1724 unfreeze_array(conf); 1725 } 1726 1727 bio = r10_bio->devs[r10_bio->read_slot].bio; 1728 r10_bio->devs[r10_bio->read_slot].bio = 1729 mddev->ro ? IO_BLOCKED : NULL; 1730 mirror = read_balance(conf, r10_bio); 1731 if (mirror == -1) { 1732 printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O" 1733 " read error for block %llu\n", 1734 mdname(mddev), 1735 bdevname(bio->bi_bdev,b), 1736 (unsigned long long)r10_bio->sector); 1737 raid_end_bio_io(r10_bio); 1738 bio_put(bio); 1739 } else { 1740 const unsigned long do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC); 1741 bio_put(bio); 1742 rdev = conf->mirrors[mirror].rdev; 1743 if (printk_ratelimit()) 1744 printk(KERN_ERR "md/raid10:%s: %s: redirecting sector %llu to" 1745 " another mirror\n", 1746 mdname(mddev), 1747 bdevname(rdev->bdev,b), 1748 (unsigned long long)r10_bio->sector); 1749 bio = bio_clone(r10_bio->master_bio, GFP_NOIO); 1750 r10_bio->devs[r10_bio->read_slot].bio = bio; 1751 bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr 1752 + rdev->data_offset; 1753 bio->bi_bdev = rdev->bdev; 1754 bio->bi_rw = READ | do_sync; 1755 bio->bi_private = r10_bio; 1756 bio->bi_end_io = raid10_end_read_request; 1757 unplug = 1; 1758 generic_make_request(bio); 1759 } 1760 } 1761 cond_resched(); 1762 } 1763 if (unplug) 1764 unplug_slaves(mddev); 1765 } 1766 1767 1768 static int init_resync(conf_t *conf) 1769 { 1770 int buffs; 1771 1772 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; 1773 BUG_ON(conf->r10buf_pool); 1774 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); 1775 if (!conf->r10buf_pool) 1776 return -ENOMEM; 1777 conf->next_resync = 0; 1778 return 0; 1779 } 1780 1781 /* 1782 * perform a "sync" on one "block" 1783 * 1784 * We need to make sure that no normal I/O request - particularly write 1785 * requests - conflict with active sync requests. 1786 * 1787 * This is achieved by tracking pending requests and a 'barrier' concept 1788 * that can be installed to exclude normal IO requests. 1789 * 1790 * Resync and recovery are handled very differently. 1791 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. 1792 * 1793 * For resync, we iterate over virtual addresses, read all copies, 1794 * and update if there are differences. If only one copy is live, 1795 * skip it. 1796 * For recovery, we iterate over physical addresses, read a good 1797 * value for each non-in_sync drive, and over-write. 1798 * 1799 * So, for recovery we may have several outstanding complex requests for a 1800 * given address, one for each out-of-sync device. We model this by allocating 1801 * a number of r10_bio structures, one for each out-of-sync device. 1802 * As we setup these structures, we collect all bio's together into a list 1803 * which we then process collectively to add pages, and then process again 1804 * to pass to generic_make_request. 1805 * 1806 * The r10_bio structures are linked using a borrowed master_bio pointer. 1807 * This link is counted in ->remaining. When the r10_bio that points to NULL 1808 * has its remaining count decremented to 0, the whole complex operation 1809 * is complete. 1810 * 1811 */ 1812 1813 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 1814 { 1815 conf_t *conf = mddev->private; 1816 r10bio_t *r10_bio; 1817 struct bio *biolist = NULL, *bio; 1818 sector_t max_sector, nr_sectors; 1819 int disk; 1820 int i; 1821 int max_sync; 1822 int sync_blocks; 1823 1824 sector_t sectors_skipped = 0; 1825 int chunks_skipped = 0; 1826 1827 if (!conf->r10buf_pool) 1828 if (init_resync(conf)) 1829 return 0; 1830 1831 skipped: 1832 max_sector = mddev->dev_sectors; 1833 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) 1834 max_sector = mddev->resync_max_sectors; 1835 if (sector_nr >= max_sector) { 1836 /* If we aborted, we need to abort the 1837 * sync on the 'current' bitmap chucks (there can 1838 * be several when recovering multiple devices). 1839 * as we may have started syncing it but not finished. 1840 * We can find the current address in 1841 * mddev->curr_resync, but for recovery, 1842 * we need to convert that to several 1843 * virtual addresses. 1844 */ 1845 if (mddev->curr_resync < max_sector) { /* aborted */ 1846 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) 1847 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 1848 &sync_blocks, 1); 1849 else for (i=0; i<conf->raid_disks; i++) { 1850 sector_t sect = 1851 raid10_find_virt(conf, mddev->curr_resync, i); 1852 bitmap_end_sync(mddev->bitmap, sect, 1853 &sync_blocks, 1); 1854 } 1855 } else /* completed sync */ 1856 conf->fullsync = 0; 1857 1858 bitmap_close_sync(mddev->bitmap); 1859 close_sync(conf); 1860 *skipped = 1; 1861 return sectors_skipped; 1862 } 1863 if (chunks_skipped >= conf->raid_disks) { 1864 /* if there has been nothing to do on any drive, 1865 * then there is nothing to do at all.. 1866 */ 1867 *skipped = 1; 1868 return (max_sector - sector_nr) + sectors_skipped; 1869 } 1870 1871 if (max_sector > mddev->resync_max) 1872 max_sector = mddev->resync_max; /* Don't do IO beyond here */ 1873 1874 /* make sure whole request will fit in a chunk - if chunks 1875 * are meaningful 1876 */ 1877 if (conf->near_copies < conf->raid_disks && 1878 max_sector > (sector_nr | conf->chunk_mask)) 1879 max_sector = (sector_nr | conf->chunk_mask) + 1; 1880 /* 1881 * If there is non-resync activity waiting for us then 1882 * put in a delay to throttle resync. 1883 */ 1884 if (!go_faster && conf->nr_waiting) 1885 msleep_interruptible(1000); 1886 1887 /* Again, very different code for resync and recovery. 1888 * Both must result in an r10bio with a list of bios that 1889 * have bi_end_io, bi_sector, bi_bdev set, 1890 * and bi_private set to the r10bio. 1891 * For recovery, we may actually create several r10bios 1892 * with 2 bios in each, that correspond to the bios in the main one. 1893 * In this case, the subordinate r10bios link back through a 1894 * borrowed master_bio pointer, and the counter in the master 1895 * includes a ref from each subordinate. 1896 */ 1897 /* First, we decide what to do and set ->bi_end_io 1898 * To end_sync_read if we want to read, and 1899 * end_sync_write if we will want to write. 1900 */ 1901 1902 max_sync = RESYNC_PAGES << (PAGE_SHIFT-9); 1903 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 1904 /* recovery... the complicated one */ 1905 int j, k; 1906 r10_bio = NULL; 1907 1908 for (i=0 ; i<conf->raid_disks; i++) 1909 if (conf->mirrors[i].rdev && 1910 !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) { 1911 int still_degraded = 0; 1912 /* want to reconstruct this device */ 1913 r10bio_t *rb2 = r10_bio; 1914 sector_t sect = raid10_find_virt(conf, sector_nr, i); 1915 int must_sync; 1916 /* Unless we are doing a full sync, we only need 1917 * to recover the block if it is set in the bitmap 1918 */ 1919 must_sync = bitmap_start_sync(mddev->bitmap, sect, 1920 &sync_blocks, 1); 1921 if (sync_blocks < max_sync) 1922 max_sync = sync_blocks; 1923 if (!must_sync && 1924 !conf->fullsync) { 1925 /* yep, skip the sync_blocks here, but don't assume 1926 * that there will never be anything to do here 1927 */ 1928 chunks_skipped = -1; 1929 continue; 1930 } 1931 1932 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); 1933 raise_barrier(conf, rb2 != NULL); 1934 atomic_set(&r10_bio->remaining, 0); 1935 1936 r10_bio->master_bio = (struct bio*)rb2; 1937 if (rb2) 1938 atomic_inc(&rb2->remaining); 1939 r10_bio->mddev = mddev; 1940 set_bit(R10BIO_IsRecover, &r10_bio->state); 1941 r10_bio->sector = sect; 1942 1943 raid10_find_phys(conf, r10_bio); 1944 1945 /* Need to check if the array will still be 1946 * degraded 1947 */ 1948 for (j=0; j<conf->raid_disks; j++) 1949 if (conf->mirrors[j].rdev == NULL || 1950 test_bit(Faulty, &conf->mirrors[j].rdev->flags)) { 1951 still_degraded = 1; 1952 break; 1953 } 1954 1955 must_sync = bitmap_start_sync(mddev->bitmap, sect, 1956 &sync_blocks, still_degraded); 1957 1958 for (j=0; j<conf->copies;j++) { 1959 int d = r10_bio->devs[j].devnum; 1960 if (conf->mirrors[d].rdev && 1961 test_bit(In_sync, &conf->mirrors[d].rdev->flags)) { 1962 /* This is where we read from */ 1963 bio = r10_bio->devs[0].bio; 1964 bio->bi_next = biolist; 1965 biolist = bio; 1966 bio->bi_private = r10_bio; 1967 bio->bi_end_io = end_sync_read; 1968 bio->bi_rw = READ; 1969 bio->bi_sector = r10_bio->devs[j].addr + 1970 conf->mirrors[d].rdev->data_offset; 1971 bio->bi_bdev = conf->mirrors[d].rdev->bdev; 1972 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 1973 atomic_inc(&r10_bio->remaining); 1974 /* and we write to 'i' */ 1975 1976 for (k=0; k<conf->copies; k++) 1977 if (r10_bio->devs[k].devnum == i) 1978 break; 1979 BUG_ON(k == conf->copies); 1980 bio = r10_bio->devs[1].bio; 1981 bio->bi_next = biolist; 1982 biolist = bio; 1983 bio->bi_private = r10_bio; 1984 bio->bi_end_io = end_sync_write; 1985 bio->bi_rw = WRITE; 1986 bio->bi_sector = r10_bio->devs[k].addr + 1987 conf->mirrors[i].rdev->data_offset; 1988 bio->bi_bdev = conf->mirrors[i].rdev->bdev; 1989 1990 r10_bio->devs[0].devnum = d; 1991 r10_bio->devs[1].devnum = i; 1992 1993 break; 1994 } 1995 } 1996 if (j == conf->copies) { 1997 /* Cannot recover, so abort the recovery */ 1998 put_buf(r10_bio); 1999 if (rb2) 2000 atomic_dec(&rb2->remaining); 2001 r10_bio = rb2; 2002 if (!test_and_set_bit(MD_RECOVERY_INTR, 2003 &mddev->recovery)) 2004 printk(KERN_INFO "md/raid10:%s: insufficient " 2005 "working devices for recovery.\n", 2006 mdname(mddev)); 2007 break; 2008 } 2009 } 2010 if (biolist == NULL) { 2011 while (r10_bio) { 2012 r10bio_t *rb2 = r10_bio; 2013 r10_bio = (r10bio_t*) rb2->master_bio; 2014 rb2->master_bio = NULL; 2015 put_buf(rb2); 2016 } 2017 goto giveup; 2018 } 2019 } else { 2020 /* resync. Schedule a read for every block at this virt offset */ 2021 int count = 0; 2022 2023 bitmap_cond_end_sync(mddev->bitmap, sector_nr); 2024 2025 if (!bitmap_start_sync(mddev->bitmap, sector_nr, 2026 &sync_blocks, mddev->degraded) && 2027 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { 2028 /* We can skip this block */ 2029 *skipped = 1; 2030 return sync_blocks + sectors_skipped; 2031 } 2032 if (sync_blocks < max_sync) 2033 max_sync = sync_blocks; 2034 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); 2035 2036 r10_bio->mddev = mddev; 2037 atomic_set(&r10_bio->remaining, 0); 2038 raise_barrier(conf, 0); 2039 conf->next_resync = sector_nr; 2040 2041 r10_bio->master_bio = NULL; 2042 r10_bio->sector = sector_nr; 2043 set_bit(R10BIO_IsSync, &r10_bio->state); 2044 raid10_find_phys(conf, r10_bio); 2045 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; 2046 2047 for (i=0; i<conf->copies; i++) { 2048 int d = r10_bio->devs[i].devnum; 2049 bio = r10_bio->devs[i].bio; 2050 bio->bi_end_io = NULL; 2051 clear_bit(BIO_UPTODATE, &bio->bi_flags); 2052 if (conf->mirrors[d].rdev == NULL || 2053 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) 2054 continue; 2055 atomic_inc(&conf->mirrors[d].rdev->nr_pending); 2056 atomic_inc(&r10_bio->remaining); 2057 bio->bi_next = biolist; 2058 biolist = bio; 2059 bio->bi_private = r10_bio; 2060 bio->bi_end_io = end_sync_read; 2061 bio->bi_rw = READ; 2062 bio->bi_sector = r10_bio->devs[i].addr + 2063 conf->mirrors[d].rdev->data_offset; 2064 bio->bi_bdev = conf->mirrors[d].rdev->bdev; 2065 count++; 2066 } 2067 2068 if (count < 2) { 2069 for (i=0; i<conf->copies; i++) { 2070 int d = r10_bio->devs[i].devnum; 2071 if (r10_bio->devs[i].bio->bi_end_io) 2072 rdev_dec_pending(conf->mirrors[d].rdev, mddev); 2073 } 2074 put_buf(r10_bio); 2075 biolist = NULL; 2076 goto giveup; 2077 } 2078 } 2079 2080 for (bio = biolist; bio ; bio=bio->bi_next) { 2081 2082 bio->bi_flags &= ~(BIO_POOL_MASK - 1); 2083 if (bio->bi_end_io) 2084 bio->bi_flags |= 1 << BIO_UPTODATE; 2085 bio->bi_vcnt = 0; 2086 bio->bi_idx = 0; 2087 bio->bi_phys_segments = 0; 2088 bio->bi_size = 0; 2089 } 2090 2091 nr_sectors = 0; 2092 if (sector_nr + max_sync < max_sector) 2093 max_sector = sector_nr + max_sync; 2094 do { 2095 struct page *page; 2096 int len = PAGE_SIZE; 2097 disk = 0; 2098 if (sector_nr + (len>>9) > max_sector) 2099 len = (max_sector - sector_nr) << 9; 2100 if (len == 0) 2101 break; 2102 for (bio= biolist ; bio ; bio=bio->bi_next) { 2103 page = bio->bi_io_vec[bio->bi_vcnt].bv_page; 2104 if (bio_add_page(bio, page, len, 0) == 0) { 2105 /* stop here */ 2106 struct bio *bio2; 2107 bio->bi_io_vec[bio->bi_vcnt].bv_page = page; 2108 for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { 2109 /* remove last page from this bio */ 2110 bio2->bi_vcnt--; 2111 bio2->bi_size -= len; 2112 bio2->bi_flags &= ~(1<< BIO_SEG_VALID); 2113 } 2114 goto bio_full; 2115 } 2116 disk = i; 2117 } 2118 nr_sectors += len>>9; 2119 sector_nr += len>>9; 2120 } while (biolist->bi_vcnt < RESYNC_PAGES); 2121 bio_full: 2122 r10_bio->sectors = nr_sectors; 2123 2124 while (biolist) { 2125 bio = biolist; 2126 biolist = biolist->bi_next; 2127 2128 bio->bi_next = NULL; 2129 r10_bio = bio->bi_private; 2130 r10_bio->sectors = nr_sectors; 2131 2132 if (bio->bi_end_io == end_sync_read) { 2133 md_sync_acct(bio->bi_bdev, nr_sectors); 2134 generic_make_request(bio); 2135 } 2136 } 2137 2138 if (sectors_skipped) 2139 /* pretend they weren't skipped, it makes 2140 * no important difference in this case 2141 */ 2142 md_done_sync(mddev, sectors_skipped, 1); 2143 2144 return sectors_skipped + nr_sectors; 2145 giveup: 2146 /* There is nowhere to write, so all non-sync 2147 * drives must be failed, so try the next chunk... 2148 */ 2149 if (sector_nr + max_sync < max_sector) 2150 max_sector = sector_nr + max_sync; 2151 2152 sectors_skipped += (max_sector - sector_nr); 2153 chunks_skipped ++; 2154 sector_nr = max_sector; 2155 goto skipped; 2156 } 2157 2158 static sector_t 2159 raid10_size(mddev_t *mddev, sector_t sectors, int raid_disks) 2160 { 2161 sector_t size; 2162 conf_t *conf = mddev->private; 2163 2164 if (!raid_disks) 2165 raid_disks = conf->raid_disks; 2166 if (!sectors) 2167 sectors = conf->dev_sectors; 2168 2169 size = sectors >> conf->chunk_shift; 2170 sector_div(size, conf->far_copies); 2171 size = size * raid_disks; 2172 sector_div(size, conf->near_copies); 2173 2174 return size << conf->chunk_shift; 2175 } 2176 2177 2178 static conf_t *setup_conf(mddev_t *mddev) 2179 { 2180 conf_t *conf = NULL; 2181 int nc, fc, fo; 2182 sector_t stride, size; 2183 int err = -EINVAL; 2184 2185 if (mddev->new_chunk_sectors < (PAGE_SIZE >> 9) || 2186 !is_power_of_2(mddev->new_chunk_sectors)) { 2187 printk(KERN_ERR "md/raid10:%s: chunk size must be " 2188 "at least PAGE_SIZE(%ld) and be a power of 2.\n", 2189 mdname(mddev), PAGE_SIZE); 2190 goto out; 2191 } 2192 2193 nc = mddev->new_layout & 255; 2194 fc = (mddev->new_layout >> 8) & 255; 2195 fo = mddev->new_layout & (1<<16); 2196 2197 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || 2198 (mddev->new_layout >> 17)) { 2199 printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n", 2200 mdname(mddev), mddev->new_layout); 2201 goto out; 2202 } 2203 2204 err = -ENOMEM; 2205 conf = kzalloc(sizeof(conf_t), GFP_KERNEL); 2206 if (!conf) 2207 goto out; 2208 2209 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, 2210 GFP_KERNEL); 2211 if (!conf->mirrors) 2212 goto out; 2213 2214 conf->tmppage = alloc_page(GFP_KERNEL); 2215 if (!conf->tmppage) 2216 goto out; 2217 2218 2219 conf->raid_disks = mddev->raid_disks; 2220 conf->near_copies = nc; 2221 conf->far_copies = fc; 2222 conf->copies = nc*fc; 2223 conf->far_offset = fo; 2224 conf->chunk_mask = mddev->new_chunk_sectors - 1; 2225 conf->chunk_shift = ffz(~mddev->new_chunk_sectors); 2226 2227 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, 2228 r10bio_pool_free, conf); 2229 if (!conf->r10bio_pool) 2230 goto out; 2231 2232 size = mddev->dev_sectors >> conf->chunk_shift; 2233 sector_div(size, fc); 2234 size = size * conf->raid_disks; 2235 sector_div(size, nc); 2236 /* 'size' is now the number of chunks in the array */ 2237 /* calculate "used chunks per device" in 'stride' */ 2238 stride = size * conf->copies; 2239 2240 /* We need to round up when dividing by raid_disks to 2241 * get the stride size. 2242 */ 2243 stride += conf->raid_disks - 1; 2244 sector_div(stride, conf->raid_disks); 2245 2246 conf->dev_sectors = stride << conf->chunk_shift; 2247 2248 if (fo) 2249 stride = 1; 2250 else 2251 sector_div(stride, fc); 2252 conf->stride = stride << conf->chunk_shift; 2253 2254 2255 spin_lock_init(&conf->device_lock); 2256 INIT_LIST_HEAD(&conf->retry_list); 2257 2258 spin_lock_init(&conf->resync_lock); 2259 init_waitqueue_head(&conf->wait_barrier); 2260 2261 conf->thread = md_register_thread(raid10d, mddev, NULL); 2262 if (!conf->thread) 2263 goto out; 2264 2265 conf->mddev = mddev; 2266 return conf; 2267 2268 out: 2269 printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n", 2270 mdname(mddev)); 2271 if (conf) { 2272 if (conf->r10bio_pool) 2273 mempool_destroy(conf->r10bio_pool); 2274 kfree(conf->mirrors); 2275 safe_put_page(conf->tmppage); 2276 kfree(conf); 2277 } 2278 return ERR_PTR(err); 2279 } 2280 2281 static int run(mddev_t *mddev) 2282 { 2283 conf_t *conf; 2284 int i, disk_idx, chunk_size; 2285 mirror_info_t *disk; 2286 mdk_rdev_t *rdev; 2287 sector_t size; 2288 2289 /* 2290 * copy the already verified devices into our private RAID10 2291 * bookkeeping area. [whatever we allocate in run(), 2292 * should be freed in stop()] 2293 */ 2294 2295 if (mddev->private == NULL) { 2296 conf = setup_conf(mddev); 2297 if (IS_ERR(conf)) 2298 return PTR_ERR(conf); 2299 mddev->private = conf; 2300 } 2301 conf = mddev->private; 2302 if (!conf) 2303 goto out; 2304 2305 mddev->queue->queue_lock = &conf->device_lock; 2306 2307 mddev->thread = conf->thread; 2308 conf->thread = NULL; 2309 2310 chunk_size = mddev->chunk_sectors << 9; 2311 blk_queue_io_min(mddev->queue, chunk_size); 2312 if (conf->raid_disks % conf->near_copies) 2313 blk_queue_io_opt(mddev->queue, chunk_size * conf->raid_disks); 2314 else 2315 blk_queue_io_opt(mddev->queue, chunk_size * 2316 (conf->raid_disks / conf->near_copies)); 2317 2318 list_for_each_entry(rdev, &mddev->disks, same_set) { 2319 disk_idx = rdev->raid_disk; 2320 if (disk_idx >= conf->raid_disks 2321 || disk_idx < 0) 2322 continue; 2323 disk = conf->mirrors + disk_idx; 2324 2325 disk->rdev = rdev; 2326 disk_stack_limits(mddev->gendisk, rdev->bdev, 2327 rdev->data_offset << 9); 2328 /* as we don't honour merge_bvec_fn, we must never risk 2329 * violating it, so limit max_segments to 1 lying 2330 * within a single page. 2331 */ 2332 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { 2333 blk_queue_max_segments(mddev->queue, 1); 2334 blk_queue_segment_boundary(mddev->queue, 2335 PAGE_CACHE_SIZE - 1); 2336 } 2337 2338 disk->head_position = 0; 2339 } 2340 /* need to check that every block has at least one working mirror */ 2341 if (!enough(conf)) { 2342 printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n", 2343 mdname(mddev)); 2344 goto out_free_conf; 2345 } 2346 2347 mddev->degraded = 0; 2348 for (i = 0; i < conf->raid_disks; i++) { 2349 2350 disk = conf->mirrors + i; 2351 2352 if (!disk->rdev || 2353 !test_bit(In_sync, &disk->rdev->flags)) { 2354 disk->head_position = 0; 2355 mddev->degraded++; 2356 if (disk->rdev) 2357 conf->fullsync = 1; 2358 } 2359 } 2360 2361 if (mddev->recovery_cp != MaxSector) 2362 printk(KERN_NOTICE "md/raid10:%s: not clean" 2363 " -- starting background reconstruction\n", 2364 mdname(mddev)); 2365 printk(KERN_INFO 2366 "md/raid10:%s: active with %d out of %d devices\n", 2367 mdname(mddev), conf->raid_disks - mddev->degraded, 2368 conf->raid_disks); 2369 /* 2370 * Ok, everything is just fine now 2371 */ 2372 mddev->dev_sectors = conf->dev_sectors; 2373 size = raid10_size(mddev, 0, 0); 2374 md_set_array_sectors(mddev, size); 2375 mddev->resync_max_sectors = size; 2376 2377 mddev->queue->unplug_fn = raid10_unplug; 2378 mddev->queue->backing_dev_info.congested_fn = raid10_congested; 2379 mddev->queue->backing_dev_info.congested_data = mddev; 2380 2381 /* Calculate max read-ahead size. 2382 * We need to readahead at least twice a whole stripe.... 2383 * maybe... 2384 */ 2385 { 2386 int stripe = conf->raid_disks * 2387 ((mddev->chunk_sectors << 9) / PAGE_SIZE); 2388 stripe /= conf->near_copies; 2389 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) 2390 mddev->queue->backing_dev_info.ra_pages = 2* stripe; 2391 } 2392 2393 if (conf->near_copies < conf->raid_disks) 2394 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); 2395 md_integrity_register(mddev); 2396 return 0; 2397 2398 out_free_conf: 2399 if (conf->r10bio_pool) 2400 mempool_destroy(conf->r10bio_pool); 2401 safe_put_page(conf->tmppage); 2402 kfree(conf->mirrors); 2403 kfree(conf); 2404 mddev->private = NULL; 2405 md_unregister_thread(mddev->thread); 2406 out: 2407 return -EIO; 2408 } 2409 2410 static int stop(mddev_t *mddev) 2411 { 2412 conf_t *conf = mddev->private; 2413 2414 raise_barrier(conf, 0); 2415 lower_barrier(conf); 2416 2417 md_unregister_thread(mddev->thread); 2418 mddev->thread = NULL; 2419 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 2420 if (conf->r10bio_pool) 2421 mempool_destroy(conf->r10bio_pool); 2422 kfree(conf->mirrors); 2423 kfree(conf); 2424 mddev->private = NULL; 2425 return 0; 2426 } 2427 2428 static void raid10_quiesce(mddev_t *mddev, int state) 2429 { 2430 conf_t *conf = mddev->private; 2431 2432 switch(state) { 2433 case 1: 2434 raise_barrier(conf, 0); 2435 break; 2436 case 0: 2437 lower_barrier(conf); 2438 break; 2439 } 2440 } 2441 2442 static void *raid10_takeover_raid0(mddev_t *mddev) 2443 { 2444 mdk_rdev_t *rdev; 2445 conf_t *conf; 2446 2447 if (mddev->degraded > 0) { 2448 printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n", 2449 mdname(mddev)); 2450 return ERR_PTR(-EINVAL); 2451 } 2452 2453 /* Set new parameters */ 2454 mddev->new_level = 10; 2455 /* new layout: far_copies = 1, near_copies = 2 */ 2456 mddev->new_layout = (1<<8) + 2; 2457 mddev->new_chunk_sectors = mddev->chunk_sectors; 2458 mddev->delta_disks = mddev->raid_disks; 2459 mddev->raid_disks *= 2; 2460 /* make sure it will be not marked as dirty */ 2461 mddev->recovery_cp = MaxSector; 2462 2463 conf = setup_conf(mddev); 2464 if (!IS_ERR(conf)) 2465 list_for_each_entry(rdev, &mddev->disks, same_set) 2466 if (rdev->raid_disk >= 0) 2467 rdev->new_raid_disk = rdev->raid_disk * 2; 2468 2469 return conf; 2470 } 2471 2472 static void *raid10_takeover(mddev_t *mddev) 2473 { 2474 struct raid0_private_data *raid0_priv; 2475 2476 /* raid10 can take over: 2477 * raid0 - providing it has only two drives 2478 */ 2479 if (mddev->level == 0) { 2480 /* for raid0 takeover only one zone is supported */ 2481 raid0_priv = mddev->private; 2482 if (raid0_priv->nr_strip_zones > 1) { 2483 printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0" 2484 " with more than one zone.\n", 2485 mdname(mddev)); 2486 return ERR_PTR(-EINVAL); 2487 } 2488 return raid10_takeover_raid0(mddev); 2489 } 2490 return ERR_PTR(-EINVAL); 2491 } 2492 2493 static struct mdk_personality raid10_personality = 2494 { 2495 .name = "raid10", 2496 .level = 10, 2497 .owner = THIS_MODULE, 2498 .make_request = make_request, 2499 .run = run, 2500 .stop = stop, 2501 .status = status, 2502 .error_handler = error, 2503 .hot_add_disk = raid10_add_disk, 2504 .hot_remove_disk= raid10_remove_disk, 2505 .spare_active = raid10_spare_active, 2506 .sync_request = sync_request, 2507 .quiesce = raid10_quiesce, 2508 .size = raid10_size, 2509 .takeover = raid10_takeover, 2510 }; 2511 2512 static int __init raid_init(void) 2513 { 2514 return register_md_personality(&raid10_personality); 2515 } 2516 2517 static void raid_exit(void) 2518 { 2519 unregister_md_personality(&raid10_personality); 2520 } 2521 2522 module_init(raid_init); 2523 module_exit(raid_exit); 2524 MODULE_LICENSE("GPL"); 2525 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD"); 2526 MODULE_ALIAS("md-personality-9"); /* RAID10 */ 2527 MODULE_ALIAS("md-raid10"); 2528 MODULE_ALIAS("md-level-10"); 2529