1 /* 2 * raid5.c : Multiple Devices driver for Linux 3 * Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman 4 * Copyright (C) 1999, 2000 Ingo Molnar 5 * 6 * RAID-5 management functions. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2, or (at your option) 11 * any later version. 12 * 13 * You should have received a copy of the GNU General Public License 14 * (for example /usr/src/linux/COPYING); if not, write to the Free 15 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 16 */ 17 18 19 #include <linux/config.h> 20 #include <linux/module.h> 21 #include <linux/slab.h> 22 #include <linux/raid/raid5.h> 23 #include <linux/highmem.h> 24 #include <linux/bitops.h> 25 #include <asm/atomic.h> 26 27 #include <linux/raid/bitmap.h> 28 29 /* 30 * Stripe cache 31 */ 32 33 #define NR_STRIPES 256 34 #define STRIPE_SIZE PAGE_SIZE 35 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 36 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 37 #define IO_THRESHOLD 1 38 #define HASH_PAGES 1 39 #define HASH_PAGES_ORDER 0 40 #define NR_HASH (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *)) 41 #define HASH_MASK (NR_HASH - 1) 42 43 #define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]) 44 45 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 46 * order without overlap. There may be several bio's per stripe+device, and 47 * a bio could span several devices. 48 * When walking this list for a particular stripe+device, we must never proceed 49 * beyond a bio that extends past this device, as the next bio might no longer 50 * be valid. 51 * This macro is used to determine the 'next' bio in the list, given the sector 52 * of the current stripe+device 53 */ 54 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL) 55 /* 56 * The following can be used to debug the driver 57 */ 58 #define RAID5_DEBUG 0 59 #define RAID5_PARANOIA 1 60 #if RAID5_PARANOIA && defined(CONFIG_SMP) 61 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock) 62 #else 63 # define CHECK_DEVLOCK() 64 #endif 65 66 #define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x))) 67 #if RAID5_DEBUG 68 #define inline 69 #define __inline__ 70 #endif 71 72 static void print_raid5_conf (raid5_conf_t *conf); 73 74 static inline void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) 75 { 76 if (atomic_dec_and_test(&sh->count)) { 77 if (!list_empty(&sh->lru)) 78 BUG(); 79 if (atomic_read(&conf->active_stripes)==0) 80 BUG(); 81 if (test_bit(STRIPE_HANDLE, &sh->state)) { 82 if (test_bit(STRIPE_DELAYED, &sh->state)) 83 list_add_tail(&sh->lru, &conf->delayed_list); 84 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && 85 conf->seq_write == sh->bm_seq) 86 list_add_tail(&sh->lru, &conf->bitmap_list); 87 else { 88 clear_bit(STRIPE_BIT_DELAY, &sh->state); 89 list_add_tail(&sh->lru, &conf->handle_list); 90 } 91 md_wakeup_thread(conf->mddev->thread); 92 } else { 93 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 94 atomic_dec(&conf->preread_active_stripes); 95 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 96 md_wakeup_thread(conf->mddev->thread); 97 } 98 list_add_tail(&sh->lru, &conf->inactive_list); 99 atomic_dec(&conf->active_stripes); 100 if (!conf->inactive_blocked || 101 atomic_read(&conf->active_stripes) < (NR_STRIPES*3/4)) 102 wake_up(&conf->wait_for_stripe); 103 } 104 } 105 } 106 static void release_stripe(struct stripe_head *sh) 107 { 108 raid5_conf_t *conf = sh->raid_conf; 109 unsigned long flags; 110 111 spin_lock_irqsave(&conf->device_lock, flags); 112 __release_stripe(conf, sh); 113 spin_unlock_irqrestore(&conf->device_lock, flags); 114 } 115 116 static void remove_hash(struct stripe_head *sh) 117 { 118 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector); 119 120 if (sh->hash_pprev) { 121 if (sh->hash_next) 122 sh->hash_next->hash_pprev = sh->hash_pprev; 123 *sh->hash_pprev = sh->hash_next; 124 sh->hash_pprev = NULL; 125 } 126 } 127 128 static __inline__ void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) 129 { 130 struct stripe_head **shp = &stripe_hash(conf, sh->sector); 131 132 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector); 133 134 CHECK_DEVLOCK(); 135 if ((sh->hash_next = *shp) != NULL) 136 (*shp)->hash_pprev = &sh->hash_next; 137 *shp = sh; 138 sh->hash_pprev = shp; 139 } 140 141 142 /* find an idle stripe, make sure it is unhashed, and return it. */ 143 static struct stripe_head *get_free_stripe(raid5_conf_t *conf) 144 { 145 struct stripe_head *sh = NULL; 146 struct list_head *first; 147 148 CHECK_DEVLOCK(); 149 if (list_empty(&conf->inactive_list)) 150 goto out; 151 first = conf->inactive_list.next; 152 sh = list_entry(first, struct stripe_head, lru); 153 list_del_init(first); 154 remove_hash(sh); 155 atomic_inc(&conf->active_stripes); 156 out: 157 return sh; 158 } 159 160 static void shrink_buffers(struct stripe_head *sh, int num) 161 { 162 struct page *p; 163 int i; 164 165 for (i=0; i<num ; i++) { 166 p = sh->dev[i].page; 167 if (!p) 168 continue; 169 sh->dev[i].page = NULL; 170 page_cache_release(p); 171 } 172 } 173 174 static int grow_buffers(struct stripe_head *sh, int num) 175 { 176 int i; 177 178 for (i=0; i<num; i++) { 179 struct page *page; 180 181 if (!(page = alloc_page(GFP_KERNEL))) { 182 return 1; 183 } 184 sh->dev[i].page = page; 185 } 186 return 0; 187 } 188 189 static void raid5_build_block (struct stripe_head *sh, int i); 190 191 static inline void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx) 192 { 193 raid5_conf_t *conf = sh->raid_conf; 194 int disks = conf->raid_disks, i; 195 196 if (atomic_read(&sh->count) != 0) 197 BUG(); 198 if (test_bit(STRIPE_HANDLE, &sh->state)) 199 BUG(); 200 201 CHECK_DEVLOCK(); 202 PRINTK("init_stripe called, stripe %llu\n", 203 (unsigned long long)sh->sector); 204 205 remove_hash(sh); 206 207 sh->sector = sector; 208 sh->pd_idx = pd_idx; 209 sh->state = 0; 210 211 for (i=disks; i--; ) { 212 struct r5dev *dev = &sh->dev[i]; 213 214 if (dev->toread || dev->towrite || dev->written || 215 test_bit(R5_LOCKED, &dev->flags)) { 216 printk("sector=%llx i=%d %p %p %p %d\n", 217 (unsigned long long)sh->sector, i, dev->toread, 218 dev->towrite, dev->written, 219 test_bit(R5_LOCKED, &dev->flags)); 220 BUG(); 221 } 222 dev->flags = 0; 223 raid5_build_block(sh, i); 224 } 225 insert_hash(conf, sh); 226 } 227 228 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector) 229 { 230 struct stripe_head *sh; 231 232 CHECK_DEVLOCK(); 233 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector); 234 for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next) 235 if (sh->sector == sector) 236 return sh; 237 PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector); 238 return NULL; 239 } 240 241 static void unplug_slaves(mddev_t *mddev); 242 static void raid5_unplug_device(request_queue_t *q); 243 244 static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, 245 int pd_idx, int noblock) 246 { 247 struct stripe_head *sh; 248 249 PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector); 250 251 spin_lock_irq(&conf->device_lock); 252 253 do { 254 wait_event_lock_irq(conf->wait_for_stripe, 255 conf->quiesce == 0, 256 conf->device_lock, /* nothing */); 257 sh = __find_stripe(conf, sector); 258 if (!sh) { 259 if (!conf->inactive_blocked) 260 sh = get_free_stripe(conf); 261 if (noblock && sh == NULL) 262 break; 263 if (!sh) { 264 conf->inactive_blocked = 1; 265 wait_event_lock_irq(conf->wait_for_stripe, 266 !list_empty(&conf->inactive_list) && 267 (atomic_read(&conf->active_stripes) < (NR_STRIPES *3/4) 268 || !conf->inactive_blocked), 269 conf->device_lock, 270 unplug_slaves(conf->mddev); 271 ); 272 conf->inactive_blocked = 0; 273 } else 274 init_stripe(sh, sector, pd_idx); 275 } else { 276 if (atomic_read(&sh->count)) { 277 if (!list_empty(&sh->lru)) 278 BUG(); 279 } else { 280 if (!test_bit(STRIPE_HANDLE, &sh->state)) 281 atomic_inc(&conf->active_stripes); 282 if (list_empty(&sh->lru)) 283 BUG(); 284 list_del_init(&sh->lru); 285 } 286 } 287 } while (sh == NULL); 288 289 if (sh) 290 atomic_inc(&sh->count); 291 292 spin_unlock_irq(&conf->device_lock); 293 return sh; 294 } 295 296 static int grow_stripes(raid5_conf_t *conf, int num) 297 { 298 struct stripe_head *sh; 299 kmem_cache_t *sc; 300 int devs = conf->raid_disks; 301 302 sprintf(conf->cache_name, "raid5/%s", mdname(conf->mddev)); 303 304 sc = kmem_cache_create(conf->cache_name, 305 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 306 0, 0, NULL, NULL); 307 if (!sc) 308 return 1; 309 conf->slab_cache = sc; 310 while (num--) { 311 sh = kmem_cache_alloc(sc, GFP_KERNEL); 312 if (!sh) 313 return 1; 314 memset(sh, 0, sizeof(*sh) + (devs-1)*sizeof(struct r5dev)); 315 sh->raid_conf = conf; 316 spin_lock_init(&sh->lock); 317 318 if (grow_buffers(sh, conf->raid_disks)) { 319 shrink_buffers(sh, conf->raid_disks); 320 kmem_cache_free(sc, sh); 321 return 1; 322 } 323 /* we just created an active stripe so... */ 324 atomic_set(&sh->count, 1); 325 atomic_inc(&conf->active_stripes); 326 INIT_LIST_HEAD(&sh->lru); 327 release_stripe(sh); 328 } 329 return 0; 330 } 331 332 static void shrink_stripes(raid5_conf_t *conf) 333 { 334 struct stripe_head *sh; 335 336 while (1) { 337 spin_lock_irq(&conf->device_lock); 338 sh = get_free_stripe(conf); 339 spin_unlock_irq(&conf->device_lock); 340 if (!sh) 341 break; 342 if (atomic_read(&sh->count)) 343 BUG(); 344 shrink_buffers(sh, conf->raid_disks); 345 kmem_cache_free(conf->slab_cache, sh); 346 atomic_dec(&conf->active_stripes); 347 } 348 kmem_cache_destroy(conf->slab_cache); 349 conf->slab_cache = NULL; 350 } 351 352 static int raid5_end_read_request (struct bio * bi, unsigned int bytes_done, 353 int error) 354 { 355 struct stripe_head *sh = bi->bi_private; 356 raid5_conf_t *conf = sh->raid_conf; 357 int disks = conf->raid_disks, i; 358 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 359 360 if (bi->bi_size) 361 return 1; 362 363 for (i=0 ; i<disks; i++) 364 if (bi == &sh->dev[i].req) 365 break; 366 367 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n", 368 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 369 uptodate); 370 if (i == disks) { 371 BUG(); 372 return 0; 373 } 374 375 if (uptodate) { 376 #if 0 377 struct bio *bio; 378 unsigned long flags; 379 spin_lock_irqsave(&conf->device_lock, flags); 380 /* we can return a buffer if we bypassed the cache or 381 * if the top buffer is not in highmem. If there are 382 * multiple buffers, leave the extra work to 383 * handle_stripe 384 */ 385 buffer = sh->bh_read[i]; 386 if (buffer && 387 (!PageHighMem(buffer->b_page) 388 || buffer->b_page == bh->b_page ) 389 ) { 390 sh->bh_read[i] = buffer->b_reqnext; 391 buffer->b_reqnext = NULL; 392 } else 393 buffer = NULL; 394 spin_unlock_irqrestore(&conf->device_lock, flags); 395 if (sh->bh_page[i]==bh->b_page) 396 set_buffer_uptodate(bh); 397 if (buffer) { 398 if (buffer->b_page != bh->b_page) 399 memcpy(buffer->b_data, bh->b_data, bh->b_size); 400 buffer->b_end_io(buffer, 1); 401 } 402 #else 403 set_bit(R5_UPTODATE, &sh->dev[i].flags); 404 #endif 405 } else { 406 md_error(conf->mddev, conf->disks[i].rdev); 407 clear_bit(R5_UPTODATE, &sh->dev[i].flags); 408 } 409 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 410 #if 0 411 /* must restore b_page before unlocking buffer... */ 412 if (sh->bh_page[i] != bh->b_page) { 413 bh->b_page = sh->bh_page[i]; 414 bh->b_data = page_address(bh->b_page); 415 clear_buffer_uptodate(bh); 416 } 417 #endif 418 clear_bit(R5_LOCKED, &sh->dev[i].flags); 419 set_bit(STRIPE_HANDLE, &sh->state); 420 release_stripe(sh); 421 return 0; 422 } 423 424 static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, 425 int error) 426 { 427 struct stripe_head *sh = bi->bi_private; 428 raid5_conf_t *conf = sh->raid_conf; 429 int disks = conf->raid_disks, i; 430 unsigned long flags; 431 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 432 433 if (bi->bi_size) 434 return 1; 435 436 for (i=0 ; i<disks; i++) 437 if (bi == &sh->dev[i].req) 438 break; 439 440 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n", 441 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 442 uptodate); 443 if (i == disks) { 444 BUG(); 445 return 0; 446 } 447 448 spin_lock_irqsave(&conf->device_lock, flags); 449 if (!uptodate) 450 md_error(conf->mddev, conf->disks[i].rdev); 451 452 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 453 454 clear_bit(R5_LOCKED, &sh->dev[i].flags); 455 set_bit(STRIPE_HANDLE, &sh->state); 456 __release_stripe(conf, sh); 457 spin_unlock_irqrestore(&conf->device_lock, flags); 458 return 0; 459 } 460 461 462 static sector_t compute_blocknr(struct stripe_head *sh, int i); 463 464 static void raid5_build_block (struct stripe_head *sh, int i) 465 { 466 struct r5dev *dev = &sh->dev[i]; 467 468 bio_init(&dev->req); 469 dev->req.bi_io_vec = &dev->vec; 470 dev->req.bi_vcnt++; 471 dev->req.bi_max_vecs++; 472 dev->vec.bv_page = dev->page; 473 dev->vec.bv_len = STRIPE_SIZE; 474 dev->vec.bv_offset = 0; 475 476 dev->req.bi_sector = sh->sector; 477 dev->req.bi_private = sh; 478 479 dev->flags = 0; 480 if (i != sh->pd_idx) 481 dev->sector = compute_blocknr(sh, i); 482 } 483 484 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 485 { 486 char b[BDEVNAME_SIZE]; 487 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 488 PRINTK("raid5: error called\n"); 489 490 if (!rdev->faulty) { 491 mddev->sb_dirty = 1; 492 if (rdev->in_sync) { 493 conf->working_disks--; 494 mddev->degraded++; 495 conf->failed_disks++; 496 rdev->in_sync = 0; 497 /* 498 * if recovery was running, make sure it aborts. 499 */ 500 set_bit(MD_RECOVERY_ERR, &mddev->recovery); 501 } 502 rdev->faulty = 1; 503 printk (KERN_ALERT 504 "raid5: Disk failure on %s, disabling device." 505 " Operation continuing on %d devices\n", 506 bdevname(rdev->bdev,b), conf->working_disks); 507 } 508 } 509 510 /* 511 * Input: a 'big' sector number, 512 * Output: index of the data and parity disk, and the sector # in them. 513 */ 514 static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks, 515 unsigned int data_disks, unsigned int * dd_idx, 516 unsigned int * pd_idx, raid5_conf_t *conf) 517 { 518 long stripe; 519 unsigned long chunk_number; 520 unsigned int chunk_offset; 521 sector_t new_sector; 522 int sectors_per_chunk = conf->chunk_size >> 9; 523 524 /* First compute the information on this sector */ 525 526 /* 527 * Compute the chunk number and the sector offset inside the chunk 528 */ 529 chunk_offset = sector_div(r_sector, sectors_per_chunk); 530 chunk_number = r_sector; 531 BUG_ON(r_sector != chunk_number); 532 533 /* 534 * Compute the stripe number 535 */ 536 stripe = chunk_number / data_disks; 537 538 /* 539 * Compute the data disk and parity disk indexes inside the stripe 540 */ 541 *dd_idx = chunk_number % data_disks; 542 543 /* 544 * Select the parity disk based on the user selected algorithm. 545 */ 546 if (conf->level == 4) 547 *pd_idx = data_disks; 548 else switch (conf->algorithm) { 549 case ALGORITHM_LEFT_ASYMMETRIC: 550 *pd_idx = data_disks - stripe % raid_disks; 551 if (*dd_idx >= *pd_idx) 552 (*dd_idx)++; 553 break; 554 case ALGORITHM_RIGHT_ASYMMETRIC: 555 *pd_idx = stripe % raid_disks; 556 if (*dd_idx >= *pd_idx) 557 (*dd_idx)++; 558 break; 559 case ALGORITHM_LEFT_SYMMETRIC: 560 *pd_idx = data_disks - stripe % raid_disks; 561 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 562 break; 563 case ALGORITHM_RIGHT_SYMMETRIC: 564 *pd_idx = stripe % raid_disks; 565 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 566 break; 567 default: 568 printk("raid5: unsupported algorithm %d\n", 569 conf->algorithm); 570 } 571 572 /* 573 * Finally, compute the new sector number 574 */ 575 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; 576 return new_sector; 577 } 578 579 580 static sector_t compute_blocknr(struct stripe_head *sh, int i) 581 { 582 raid5_conf_t *conf = sh->raid_conf; 583 int raid_disks = conf->raid_disks, data_disks = raid_disks - 1; 584 sector_t new_sector = sh->sector, check; 585 int sectors_per_chunk = conf->chunk_size >> 9; 586 sector_t stripe; 587 int chunk_offset; 588 int chunk_number, dummy1, dummy2, dd_idx = i; 589 sector_t r_sector; 590 591 chunk_offset = sector_div(new_sector, sectors_per_chunk); 592 stripe = new_sector; 593 BUG_ON(new_sector != stripe); 594 595 596 switch (conf->algorithm) { 597 case ALGORITHM_LEFT_ASYMMETRIC: 598 case ALGORITHM_RIGHT_ASYMMETRIC: 599 if (i > sh->pd_idx) 600 i--; 601 break; 602 case ALGORITHM_LEFT_SYMMETRIC: 603 case ALGORITHM_RIGHT_SYMMETRIC: 604 if (i < sh->pd_idx) 605 i += raid_disks; 606 i -= (sh->pd_idx + 1); 607 break; 608 default: 609 printk("raid5: unsupported algorithm %d\n", 610 conf->algorithm); 611 } 612 613 chunk_number = stripe * data_disks + i; 614 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; 615 616 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf); 617 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) { 618 printk("compute_blocknr: map not correct\n"); 619 return 0; 620 } 621 return r_sector; 622 } 623 624 625 626 /* 627 * Copy data between a page in the stripe cache, and a bio. 628 * There are no alignment or size guarantees between the page or the 629 * bio except that there is some overlap. 630 * All iovecs in the bio must be considered. 631 */ 632 static void copy_data(int frombio, struct bio *bio, 633 struct page *page, 634 sector_t sector) 635 { 636 char *pa = page_address(page); 637 struct bio_vec *bvl; 638 int i; 639 int page_offset; 640 641 if (bio->bi_sector >= sector) 642 page_offset = (signed)(bio->bi_sector - sector) * 512; 643 else 644 page_offset = (signed)(sector - bio->bi_sector) * -512; 645 bio_for_each_segment(bvl, bio, i) { 646 int len = bio_iovec_idx(bio,i)->bv_len; 647 int clen; 648 int b_offset = 0; 649 650 if (page_offset < 0) { 651 b_offset = -page_offset; 652 page_offset += b_offset; 653 len -= b_offset; 654 } 655 656 if (len > 0 && page_offset + len > STRIPE_SIZE) 657 clen = STRIPE_SIZE - page_offset; 658 else clen = len; 659 660 if (clen > 0) { 661 char *ba = __bio_kmap_atomic(bio, i, KM_USER0); 662 if (frombio) 663 memcpy(pa+page_offset, ba+b_offset, clen); 664 else 665 memcpy(ba+b_offset, pa+page_offset, clen); 666 __bio_kunmap_atomic(ba, KM_USER0); 667 } 668 if (clen < len) /* hit end of page */ 669 break; 670 page_offset += len; 671 } 672 } 673 674 #define check_xor() do { \ 675 if (count == MAX_XOR_BLOCKS) { \ 676 xor_block(count, STRIPE_SIZE, ptr); \ 677 count = 1; \ 678 } \ 679 } while(0) 680 681 682 static void compute_block(struct stripe_head *sh, int dd_idx) 683 { 684 raid5_conf_t *conf = sh->raid_conf; 685 int i, count, disks = conf->raid_disks; 686 void *ptr[MAX_XOR_BLOCKS], *p; 687 688 PRINTK("compute_block, stripe %llu, idx %d\n", 689 (unsigned long long)sh->sector, dd_idx); 690 691 ptr[0] = page_address(sh->dev[dd_idx].page); 692 memset(ptr[0], 0, STRIPE_SIZE); 693 count = 1; 694 for (i = disks ; i--; ) { 695 if (i == dd_idx) 696 continue; 697 p = page_address(sh->dev[i].page); 698 if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) 699 ptr[count++] = p; 700 else 701 printk("compute_block() %d, stripe %llu, %d" 702 " not present\n", dd_idx, 703 (unsigned long long)sh->sector, i); 704 705 check_xor(); 706 } 707 if (count != 1) 708 xor_block(count, STRIPE_SIZE, ptr); 709 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 710 } 711 712 static void compute_parity(struct stripe_head *sh, int method) 713 { 714 raid5_conf_t *conf = sh->raid_conf; 715 int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count; 716 void *ptr[MAX_XOR_BLOCKS]; 717 struct bio *chosen; 718 719 PRINTK("compute_parity, stripe %llu, method %d\n", 720 (unsigned long long)sh->sector, method); 721 722 count = 1; 723 ptr[0] = page_address(sh->dev[pd_idx].page); 724 switch(method) { 725 case READ_MODIFY_WRITE: 726 if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags)) 727 BUG(); 728 for (i=disks ; i-- ;) { 729 if (i==pd_idx) 730 continue; 731 if (sh->dev[i].towrite && 732 test_bit(R5_UPTODATE, &sh->dev[i].flags)) { 733 ptr[count++] = page_address(sh->dev[i].page); 734 chosen = sh->dev[i].towrite; 735 sh->dev[i].towrite = NULL; 736 737 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 738 wake_up(&conf->wait_for_overlap); 739 740 if (sh->dev[i].written) BUG(); 741 sh->dev[i].written = chosen; 742 check_xor(); 743 } 744 } 745 break; 746 case RECONSTRUCT_WRITE: 747 memset(ptr[0], 0, STRIPE_SIZE); 748 for (i= disks; i-- ;) 749 if (i!=pd_idx && sh->dev[i].towrite) { 750 chosen = sh->dev[i].towrite; 751 sh->dev[i].towrite = NULL; 752 753 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 754 wake_up(&conf->wait_for_overlap); 755 756 if (sh->dev[i].written) BUG(); 757 sh->dev[i].written = chosen; 758 } 759 break; 760 case CHECK_PARITY: 761 break; 762 } 763 if (count>1) { 764 xor_block(count, STRIPE_SIZE, ptr); 765 count = 1; 766 } 767 768 for (i = disks; i--;) 769 if (sh->dev[i].written) { 770 sector_t sector = sh->dev[i].sector; 771 struct bio *wbi = sh->dev[i].written; 772 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { 773 copy_data(1, wbi, sh->dev[i].page, sector); 774 wbi = r5_next_bio(wbi, sector); 775 } 776 777 set_bit(R5_LOCKED, &sh->dev[i].flags); 778 set_bit(R5_UPTODATE, &sh->dev[i].flags); 779 } 780 781 switch(method) { 782 case RECONSTRUCT_WRITE: 783 case CHECK_PARITY: 784 for (i=disks; i--;) 785 if (i != pd_idx) { 786 ptr[count++] = page_address(sh->dev[i].page); 787 check_xor(); 788 } 789 break; 790 case READ_MODIFY_WRITE: 791 for (i = disks; i--;) 792 if (sh->dev[i].written) { 793 ptr[count++] = page_address(sh->dev[i].page); 794 check_xor(); 795 } 796 } 797 if (count != 1) 798 xor_block(count, STRIPE_SIZE, ptr); 799 800 if (method != CHECK_PARITY) { 801 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 802 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 803 } else 804 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 805 } 806 807 /* 808 * Each stripe/dev can have one or more bion attached. 809 * toread/towrite point to the first in a chain. 810 * The bi_next chain must be in order. 811 */ 812 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) 813 { 814 struct bio **bip; 815 raid5_conf_t *conf = sh->raid_conf; 816 int firstwrite=0; 817 818 PRINTK("adding bh b#%llu to stripe s#%llu\n", 819 (unsigned long long)bi->bi_sector, 820 (unsigned long long)sh->sector); 821 822 823 spin_lock(&sh->lock); 824 spin_lock_irq(&conf->device_lock); 825 if (forwrite) { 826 bip = &sh->dev[dd_idx].towrite; 827 if (*bip == NULL && sh->dev[dd_idx].written == NULL) 828 firstwrite = 1; 829 } else 830 bip = &sh->dev[dd_idx].toread; 831 while (*bip && (*bip)->bi_sector < bi->bi_sector) { 832 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) 833 goto overlap; 834 bip = & (*bip)->bi_next; 835 } 836 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) 837 goto overlap; 838 839 if (*bip && bi->bi_next && (*bip) != bi->bi_next) 840 BUG(); 841 if (*bip) 842 bi->bi_next = *bip; 843 *bip = bi; 844 bi->bi_phys_segments ++; 845 spin_unlock_irq(&conf->device_lock); 846 spin_unlock(&sh->lock); 847 848 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n", 849 (unsigned long long)bi->bi_sector, 850 (unsigned long long)sh->sector, dd_idx); 851 852 if (conf->mddev->bitmap && firstwrite) { 853 sh->bm_seq = conf->seq_write; 854 bitmap_startwrite(conf->mddev->bitmap, sh->sector, 855 STRIPE_SECTORS, 0); 856 set_bit(STRIPE_BIT_DELAY, &sh->state); 857 } 858 859 if (forwrite) { 860 /* check if page is covered */ 861 sector_t sector = sh->dev[dd_idx].sector; 862 for (bi=sh->dev[dd_idx].towrite; 863 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && 864 bi && bi->bi_sector <= sector; 865 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { 866 if (bi->bi_sector + (bi->bi_size>>9) >= sector) 867 sector = bi->bi_sector + (bi->bi_size>>9); 868 } 869 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) 870 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); 871 } 872 return 1; 873 874 overlap: 875 set_bit(R5_Overlap, &sh->dev[dd_idx].flags); 876 spin_unlock_irq(&conf->device_lock); 877 spin_unlock(&sh->lock); 878 return 0; 879 } 880 881 882 /* 883 * handle_stripe - do things to a stripe. 884 * 885 * We lock the stripe and then examine the state of various bits 886 * to see what needs to be done. 887 * Possible results: 888 * return some read request which now have data 889 * return some write requests which are safely on disc 890 * schedule a read on some buffers 891 * schedule a write of some buffers 892 * return confirmation of parity correctness 893 * 894 * Parity calculations are done inside the stripe lock 895 * buffers are taken off read_list or write_list, and bh_cache buffers 896 * get BH_Lock set before the stripe lock is released. 897 * 898 */ 899 900 static void handle_stripe(struct stripe_head *sh) 901 { 902 raid5_conf_t *conf = sh->raid_conf; 903 int disks = conf->raid_disks; 904 struct bio *return_bi= NULL; 905 struct bio *bi; 906 int i; 907 int syncing; 908 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0; 909 int non_overwrite = 0; 910 int failed_num=0; 911 struct r5dev *dev; 912 913 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n", 914 (unsigned long long)sh->sector, atomic_read(&sh->count), 915 sh->pd_idx); 916 917 spin_lock(&sh->lock); 918 clear_bit(STRIPE_HANDLE, &sh->state); 919 clear_bit(STRIPE_DELAYED, &sh->state); 920 921 syncing = test_bit(STRIPE_SYNCING, &sh->state); 922 /* Now to look around and see what can be done */ 923 924 for (i=disks; i--; ) { 925 mdk_rdev_t *rdev; 926 dev = &sh->dev[i]; 927 clear_bit(R5_Insync, &dev->flags); 928 clear_bit(R5_Syncio, &dev->flags); 929 930 PRINTK("check %d: state 0x%lx read %p write %p written %p\n", 931 i, dev->flags, dev->toread, dev->towrite, dev->written); 932 /* maybe we can reply to a read */ 933 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { 934 struct bio *rbi, *rbi2; 935 PRINTK("Return read for disc %d\n", i); 936 spin_lock_irq(&conf->device_lock); 937 rbi = dev->toread; 938 dev->toread = NULL; 939 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 940 wake_up(&conf->wait_for_overlap); 941 spin_unlock_irq(&conf->device_lock); 942 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { 943 copy_data(0, rbi, dev->page, dev->sector); 944 rbi2 = r5_next_bio(rbi, dev->sector); 945 spin_lock_irq(&conf->device_lock); 946 if (--rbi->bi_phys_segments == 0) { 947 rbi->bi_next = return_bi; 948 return_bi = rbi; 949 } 950 spin_unlock_irq(&conf->device_lock); 951 rbi = rbi2; 952 } 953 } 954 955 /* now count some things */ 956 if (test_bit(R5_LOCKED, &dev->flags)) locked++; 957 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++; 958 959 960 if (dev->toread) to_read++; 961 if (dev->towrite) { 962 to_write++; 963 if (!test_bit(R5_OVERWRITE, &dev->flags)) 964 non_overwrite++; 965 } 966 if (dev->written) written++; 967 rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */ 968 if (!rdev || !rdev->in_sync) { 969 failed++; 970 failed_num = i; 971 } else 972 set_bit(R5_Insync, &dev->flags); 973 } 974 PRINTK("locked=%d uptodate=%d to_read=%d" 975 " to_write=%d failed=%d failed_num=%d\n", 976 locked, uptodate, to_read, to_write, failed, failed_num); 977 /* check if the array has lost two devices and, if so, some requests might 978 * need to be failed 979 */ 980 if (failed > 1 && to_read+to_write+written) { 981 for (i=disks; i--; ) { 982 int bitmap_end = 0; 983 spin_lock_irq(&conf->device_lock); 984 /* fail all writes first */ 985 bi = sh->dev[i].towrite; 986 sh->dev[i].towrite = NULL; 987 if (bi) { to_write--; bitmap_end = 1; } 988 989 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 990 wake_up(&conf->wait_for_overlap); 991 992 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 993 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 994 clear_bit(BIO_UPTODATE, &bi->bi_flags); 995 if (--bi->bi_phys_segments == 0) { 996 md_write_end(conf->mddev); 997 bi->bi_next = return_bi; 998 return_bi = bi; 999 } 1000 bi = nextbi; 1001 } 1002 /* and fail all 'written' */ 1003 bi = sh->dev[i].written; 1004 sh->dev[i].written = NULL; 1005 if (bi) bitmap_end = 1; 1006 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { 1007 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 1008 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1009 if (--bi->bi_phys_segments == 0) { 1010 md_write_end(conf->mddev); 1011 bi->bi_next = return_bi; 1012 return_bi = bi; 1013 } 1014 bi = bi2; 1015 } 1016 1017 /* fail any reads if this device is non-operational */ 1018 if (!test_bit(R5_Insync, &sh->dev[i].flags)) { 1019 bi = sh->dev[i].toread; 1020 sh->dev[i].toread = NULL; 1021 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1022 wake_up(&conf->wait_for_overlap); 1023 if (bi) to_read--; 1024 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 1025 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 1026 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1027 if (--bi->bi_phys_segments == 0) { 1028 bi->bi_next = return_bi; 1029 return_bi = bi; 1030 } 1031 bi = nextbi; 1032 } 1033 } 1034 spin_unlock_irq(&conf->device_lock); 1035 if (bitmap_end) 1036 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1037 STRIPE_SECTORS, 0, 0); 1038 } 1039 } 1040 if (failed > 1 && syncing) { 1041 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 1042 clear_bit(STRIPE_SYNCING, &sh->state); 1043 syncing = 0; 1044 } 1045 1046 /* might be able to return some write requests if the parity block 1047 * is safe, or on a failed drive 1048 */ 1049 dev = &sh->dev[sh->pd_idx]; 1050 if ( written && 1051 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) && 1052 test_bit(R5_UPTODATE, &dev->flags)) 1053 || (failed == 1 && failed_num == sh->pd_idx)) 1054 ) { 1055 /* any written block on an uptodate or failed drive can be returned. 1056 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but 1057 * never LOCKED, so we don't need to test 'failed' directly. 1058 */ 1059 for (i=disks; i--; ) 1060 if (sh->dev[i].written) { 1061 dev = &sh->dev[i]; 1062 if (!test_bit(R5_LOCKED, &dev->flags) && 1063 test_bit(R5_UPTODATE, &dev->flags) ) { 1064 /* We can return any write requests */ 1065 struct bio *wbi, *wbi2; 1066 int bitmap_end = 0; 1067 PRINTK("Return write for disc %d\n", i); 1068 spin_lock_irq(&conf->device_lock); 1069 wbi = dev->written; 1070 dev->written = NULL; 1071 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { 1072 wbi2 = r5_next_bio(wbi, dev->sector); 1073 if (--wbi->bi_phys_segments == 0) { 1074 md_write_end(conf->mddev); 1075 wbi->bi_next = return_bi; 1076 return_bi = wbi; 1077 } 1078 wbi = wbi2; 1079 } 1080 if (dev->towrite == NULL) 1081 bitmap_end = 1; 1082 spin_unlock_irq(&conf->device_lock); 1083 if (bitmap_end) 1084 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1085 STRIPE_SECTORS, 1086 !test_bit(STRIPE_DEGRADED, &sh->state), 0); 1087 } 1088 } 1089 } 1090 1091 /* Now we might consider reading some blocks, either to check/generate 1092 * parity, or to satisfy requests 1093 * or to load a block that is being partially written. 1094 */ 1095 if (to_read || non_overwrite || (syncing && (uptodate < disks))) { 1096 for (i=disks; i--;) { 1097 dev = &sh->dev[i]; 1098 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1099 (dev->toread || 1100 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 1101 syncing || 1102 (failed && (sh->dev[failed_num].toread || 1103 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags)))) 1104 ) 1105 ) { 1106 /* we would like to get this block, possibly 1107 * by computing it, but we might not be able to 1108 */ 1109 if (uptodate == disks-1) { 1110 PRINTK("Computing block %d\n", i); 1111 compute_block(sh, i); 1112 uptodate++; 1113 } else if (test_bit(R5_Insync, &dev->flags)) { 1114 set_bit(R5_LOCKED, &dev->flags); 1115 set_bit(R5_Wantread, &dev->flags); 1116 #if 0 1117 /* if I am just reading this block and we don't have 1118 a failed drive, or any pending writes then sidestep the cache */ 1119 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext && 1120 ! syncing && !failed && !to_write) { 1121 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page; 1122 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data; 1123 } 1124 #endif 1125 locked++; 1126 PRINTK("Reading block %d (sync=%d)\n", 1127 i, syncing); 1128 if (syncing) 1129 md_sync_acct(conf->disks[i].rdev->bdev, 1130 STRIPE_SECTORS); 1131 } 1132 } 1133 } 1134 set_bit(STRIPE_HANDLE, &sh->state); 1135 } 1136 1137 /* now to consider writing and what else, if anything should be read */ 1138 if (to_write) { 1139 int rmw=0, rcw=0; 1140 for (i=disks ; i--;) { 1141 /* would I have to read this buffer for read_modify_write */ 1142 dev = &sh->dev[i]; 1143 if ((dev->towrite || i == sh->pd_idx) && 1144 (!test_bit(R5_LOCKED, &dev->flags) 1145 #if 0 1146 || sh->bh_page[i]!=bh->b_page 1147 #endif 1148 ) && 1149 !test_bit(R5_UPTODATE, &dev->flags)) { 1150 if (test_bit(R5_Insync, &dev->flags) 1151 /* && !(!mddev->insync && i == sh->pd_idx) */ 1152 ) 1153 rmw++; 1154 else rmw += 2*disks; /* cannot read it */ 1155 } 1156 /* Would I have to read this buffer for reconstruct_write */ 1157 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 1158 (!test_bit(R5_LOCKED, &dev->flags) 1159 #if 0 1160 || sh->bh_page[i] != bh->b_page 1161 #endif 1162 ) && 1163 !test_bit(R5_UPTODATE, &dev->flags)) { 1164 if (test_bit(R5_Insync, &dev->flags)) rcw++; 1165 else rcw += 2*disks; 1166 } 1167 } 1168 PRINTK("for sector %llu, rmw=%d rcw=%d\n", 1169 (unsigned long long)sh->sector, rmw, rcw); 1170 set_bit(STRIPE_HANDLE, &sh->state); 1171 if (rmw < rcw && rmw > 0) 1172 /* prefer read-modify-write, but need to get some data */ 1173 for (i=disks; i--;) { 1174 dev = &sh->dev[i]; 1175 if ((dev->towrite || i == sh->pd_idx) && 1176 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1177 test_bit(R5_Insync, &dev->flags)) { 1178 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1179 { 1180 PRINTK("Read_old block %d for r-m-w\n", i); 1181 set_bit(R5_LOCKED, &dev->flags); 1182 set_bit(R5_Wantread, &dev->flags); 1183 locked++; 1184 } else { 1185 set_bit(STRIPE_DELAYED, &sh->state); 1186 set_bit(STRIPE_HANDLE, &sh->state); 1187 } 1188 } 1189 } 1190 if (rcw <= rmw && rcw > 0) 1191 /* want reconstruct write, but need to get some data */ 1192 for (i=disks; i--;) { 1193 dev = &sh->dev[i]; 1194 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 1195 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1196 test_bit(R5_Insync, &dev->flags)) { 1197 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1198 { 1199 PRINTK("Read_old block %d for Reconstruct\n", i); 1200 set_bit(R5_LOCKED, &dev->flags); 1201 set_bit(R5_Wantread, &dev->flags); 1202 locked++; 1203 } else { 1204 set_bit(STRIPE_DELAYED, &sh->state); 1205 set_bit(STRIPE_HANDLE, &sh->state); 1206 } 1207 } 1208 } 1209 /* now if nothing is locked, and if we have enough data, we can start a write request */ 1210 if (locked == 0 && (rcw == 0 ||rmw == 0) && 1211 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 1212 PRINTK("Computing parity...\n"); 1213 compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE); 1214 /* now every locked buffer is ready to be written */ 1215 for (i=disks; i--;) 1216 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { 1217 PRINTK("Writing block %d\n", i); 1218 locked++; 1219 set_bit(R5_Wantwrite, &sh->dev[i].flags); 1220 if (!test_bit(R5_Insync, &sh->dev[i].flags) 1221 || (i==sh->pd_idx && failed == 0)) 1222 set_bit(STRIPE_INSYNC, &sh->state); 1223 } 1224 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 1225 atomic_dec(&conf->preread_active_stripes); 1226 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 1227 md_wakeup_thread(conf->mddev->thread); 1228 } 1229 } 1230 } 1231 1232 /* maybe we need to check and possibly fix the parity for this stripe 1233 * Any reads will already have been scheduled, so we just see if enough data 1234 * is available 1235 */ 1236 if (syncing && locked == 0 && 1237 !test_bit(STRIPE_INSYNC, &sh->state) && failed <= 1) { 1238 set_bit(STRIPE_HANDLE, &sh->state); 1239 if (failed == 0) { 1240 char *pagea; 1241 if (uptodate != disks) 1242 BUG(); 1243 compute_parity(sh, CHECK_PARITY); 1244 uptodate--; 1245 pagea = page_address(sh->dev[sh->pd_idx].page); 1246 if ((*(u32*)pagea) == 0 && 1247 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) { 1248 /* parity is correct (on disc, not in buffer any more) */ 1249 set_bit(STRIPE_INSYNC, &sh->state); 1250 } 1251 } 1252 if (!test_bit(STRIPE_INSYNC, &sh->state)) { 1253 if (failed==0) 1254 failed_num = sh->pd_idx; 1255 /* should be able to compute the missing block and write it to spare */ 1256 if (!test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)) { 1257 if (uptodate+1 != disks) 1258 BUG(); 1259 compute_block(sh, failed_num); 1260 uptodate++; 1261 } 1262 if (uptodate != disks) 1263 BUG(); 1264 dev = &sh->dev[failed_num]; 1265 set_bit(R5_LOCKED, &dev->flags); 1266 set_bit(R5_Wantwrite, &dev->flags); 1267 clear_bit(STRIPE_DEGRADED, &sh->state); 1268 locked++; 1269 set_bit(STRIPE_INSYNC, &sh->state); 1270 set_bit(R5_Syncio, &dev->flags); 1271 } 1272 } 1273 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 1274 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 1275 clear_bit(STRIPE_SYNCING, &sh->state); 1276 } 1277 1278 spin_unlock(&sh->lock); 1279 1280 while ((bi=return_bi)) { 1281 int bytes = bi->bi_size; 1282 1283 return_bi = bi->bi_next; 1284 bi->bi_next = NULL; 1285 bi->bi_size = 0; 1286 bi->bi_end_io(bi, bytes, 0); 1287 } 1288 for (i=disks; i-- ;) { 1289 int rw; 1290 struct bio *bi; 1291 mdk_rdev_t *rdev; 1292 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 1293 rw = 1; 1294 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 1295 rw = 0; 1296 else 1297 continue; 1298 1299 bi = &sh->dev[i].req; 1300 1301 bi->bi_rw = rw; 1302 if (rw) 1303 bi->bi_end_io = raid5_end_write_request; 1304 else 1305 bi->bi_end_io = raid5_end_read_request; 1306 1307 rcu_read_lock(); 1308 rdev = conf->disks[i].rdev; 1309 if (rdev && rdev->faulty) 1310 rdev = NULL; 1311 if (rdev) 1312 atomic_inc(&rdev->nr_pending); 1313 rcu_read_unlock(); 1314 1315 if (rdev) { 1316 if (test_bit(R5_Syncio, &sh->dev[i].flags)) 1317 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 1318 1319 bi->bi_bdev = rdev->bdev; 1320 PRINTK("for %llu schedule op %ld on disc %d\n", 1321 (unsigned long long)sh->sector, bi->bi_rw, i); 1322 atomic_inc(&sh->count); 1323 bi->bi_sector = sh->sector + rdev->data_offset; 1324 bi->bi_flags = 1 << BIO_UPTODATE; 1325 bi->bi_vcnt = 1; 1326 bi->bi_max_vecs = 1; 1327 bi->bi_idx = 0; 1328 bi->bi_io_vec = &sh->dev[i].vec; 1329 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 1330 bi->bi_io_vec[0].bv_offset = 0; 1331 bi->bi_size = STRIPE_SIZE; 1332 bi->bi_next = NULL; 1333 generic_make_request(bi); 1334 } else { 1335 if (rw == 1) 1336 set_bit(STRIPE_DEGRADED, &sh->state); 1337 PRINTK("skip op %ld on disc %d for sector %llu\n", 1338 bi->bi_rw, i, (unsigned long long)sh->sector); 1339 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1340 set_bit(STRIPE_HANDLE, &sh->state); 1341 } 1342 } 1343 } 1344 1345 static inline void raid5_activate_delayed(raid5_conf_t *conf) 1346 { 1347 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { 1348 while (!list_empty(&conf->delayed_list)) { 1349 struct list_head *l = conf->delayed_list.next; 1350 struct stripe_head *sh; 1351 sh = list_entry(l, struct stripe_head, lru); 1352 list_del_init(l); 1353 clear_bit(STRIPE_DELAYED, &sh->state); 1354 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1355 atomic_inc(&conf->preread_active_stripes); 1356 list_add_tail(&sh->lru, &conf->handle_list); 1357 } 1358 } 1359 } 1360 1361 static inline void activate_bit_delay(raid5_conf_t *conf) 1362 { 1363 /* device_lock is held */ 1364 struct list_head head; 1365 list_add(&head, &conf->bitmap_list); 1366 list_del_init(&conf->bitmap_list); 1367 while (!list_empty(&head)) { 1368 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); 1369 list_del_init(&sh->lru); 1370 atomic_inc(&sh->count); 1371 __release_stripe(conf, sh); 1372 } 1373 } 1374 1375 static void unplug_slaves(mddev_t *mddev) 1376 { 1377 raid5_conf_t *conf = mddev_to_conf(mddev); 1378 int i; 1379 1380 rcu_read_lock(); 1381 for (i=0; i<mddev->raid_disks; i++) { 1382 mdk_rdev_t *rdev = conf->disks[i].rdev; 1383 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) { 1384 request_queue_t *r_queue = bdev_get_queue(rdev->bdev); 1385 1386 atomic_inc(&rdev->nr_pending); 1387 rcu_read_unlock(); 1388 1389 if (r_queue->unplug_fn) 1390 r_queue->unplug_fn(r_queue); 1391 1392 rdev_dec_pending(rdev, mddev); 1393 rcu_read_lock(); 1394 } 1395 } 1396 rcu_read_unlock(); 1397 } 1398 1399 static void raid5_unplug_device(request_queue_t *q) 1400 { 1401 mddev_t *mddev = q->queuedata; 1402 raid5_conf_t *conf = mddev_to_conf(mddev); 1403 unsigned long flags; 1404 1405 spin_lock_irqsave(&conf->device_lock, flags); 1406 1407 if (blk_remove_plug(q)) { 1408 conf->seq_flush++; 1409 raid5_activate_delayed(conf); 1410 } 1411 md_wakeup_thread(mddev->thread); 1412 1413 spin_unlock_irqrestore(&conf->device_lock, flags); 1414 1415 unplug_slaves(mddev); 1416 } 1417 1418 static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk, 1419 sector_t *error_sector) 1420 { 1421 mddev_t *mddev = q->queuedata; 1422 raid5_conf_t *conf = mddev_to_conf(mddev); 1423 int i, ret = 0; 1424 1425 rcu_read_lock(); 1426 for (i=0; i<mddev->raid_disks && ret == 0; i++) { 1427 mdk_rdev_t *rdev = conf->disks[i].rdev; 1428 if (rdev && !rdev->faulty) { 1429 struct block_device *bdev = rdev->bdev; 1430 request_queue_t *r_queue = bdev_get_queue(bdev); 1431 1432 if (!r_queue->issue_flush_fn) 1433 ret = -EOPNOTSUPP; 1434 else { 1435 atomic_inc(&rdev->nr_pending); 1436 rcu_read_unlock(); 1437 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, 1438 error_sector); 1439 rdev_dec_pending(rdev, mddev); 1440 rcu_read_lock(); 1441 } 1442 } 1443 } 1444 rcu_read_unlock(); 1445 return ret; 1446 } 1447 1448 static inline void raid5_plug_device(raid5_conf_t *conf) 1449 { 1450 spin_lock_irq(&conf->device_lock); 1451 blk_plug_device(conf->mddev->queue); 1452 spin_unlock_irq(&conf->device_lock); 1453 } 1454 1455 static int make_request (request_queue_t *q, struct bio * bi) 1456 { 1457 mddev_t *mddev = q->queuedata; 1458 raid5_conf_t *conf = mddev_to_conf(mddev); 1459 const unsigned int raid_disks = conf->raid_disks; 1460 const unsigned int data_disks = raid_disks - 1; 1461 unsigned int dd_idx, pd_idx; 1462 sector_t new_sector; 1463 sector_t logical_sector, last_sector; 1464 struct stripe_head *sh; 1465 const int rw = bio_data_dir(bi); 1466 1467 if (unlikely(bio_barrier(bi))) { 1468 bio_endio(bi, bi->bi_size, -EOPNOTSUPP); 1469 return 0; 1470 } 1471 1472 md_write_start(mddev, bi); 1473 1474 disk_stat_inc(mddev->gendisk, ios[rw]); 1475 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi)); 1476 1477 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 1478 last_sector = bi->bi_sector + (bi->bi_size>>9); 1479 bi->bi_next = NULL; 1480 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ 1481 1482 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { 1483 DEFINE_WAIT(w); 1484 1485 new_sector = raid5_compute_sector(logical_sector, 1486 raid_disks, data_disks, &dd_idx, &pd_idx, conf); 1487 1488 PRINTK("raid5: make_request, sector %llu logical %llu\n", 1489 (unsigned long long)new_sector, 1490 (unsigned long long)logical_sector); 1491 1492 retry: 1493 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); 1494 sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK)); 1495 if (sh) { 1496 if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { 1497 /* Add failed due to overlap. Flush everything 1498 * and wait a while 1499 */ 1500 raid5_unplug_device(mddev->queue); 1501 release_stripe(sh); 1502 schedule(); 1503 goto retry; 1504 } 1505 finish_wait(&conf->wait_for_overlap, &w); 1506 raid5_plug_device(conf); 1507 handle_stripe(sh); 1508 release_stripe(sh); 1509 1510 } else { 1511 /* cannot get stripe for read-ahead, just give-up */ 1512 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1513 finish_wait(&conf->wait_for_overlap, &w); 1514 break; 1515 } 1516 1517 } 1518 spin_lock_irq(&conf->device_lock); 1519 if (--bi->bi_phys_segments == 0) { 1520 int bytes = bi->bi_size; 1521 1522 if ( bio_data_dir(bi) == WRITE ) 1523 md_write_end(mddev); 1524 bi->bi_size = 0; 1525 bi->bi_end_io(bi, bytes, 0); 1526 } 1527 spin_unlock_irq(&conf->device_lock); 1528 return 0; 1529 } 1530 1531 /* FIXME go_faster isn't used */ 1532 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 1533 { 1534 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1535 struct stripe_head *sh; 1536 int sectors_per_chunk = conf->chunk_size >> 9; 1537 sector_t x; 1538 unsigned long stripe; 1539 int chunk_offset; 1540 int dd_idx, pd_idx; 1541 sector_t first_sector; 1542 int raid_disks = conf->raid_disks; 1543 int data_disks = raid_disks-1; 1544 sector_t max_sector = mddev->size << 1; 1545 int sync_blocks; 1546 1547 if (sector_nr >= max_sector) { 1548 /* just being told to finish up .. nothing much to do */ 1549 unplug_slaves(mddev); 1550 1551 if (mddev->curr_resync < max_sector) /* aborted */ 1552 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 1553 &sync_blocks, 1); 1554 else /* compelted sync */ 1555 conf->fullsync = 0; 1556 bitmap_close_sync(mddev->bitmap); 1557 1558 return 0; 1559 } 1560 /* if there is 1 or more failed drives and we are trying 1561 * to resync, then assert that we are finished, because there is 1562 * nothing we can do. 1563 */ 1564 if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 1565 sector_t rv = (mddev->size << 1) - sector_nr; 1566 *skipped = 1; 1567 return rv; 1568 } 1569 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && 1570 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { 1571 /* we can skip this block, and probably more */ 1572 sync_blocks /= STRIPE_SECTORS; 1573 *skipped = 1; 1574 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ 1575 } 1576 1577 x = sector_nr; 1578 chunk_offset = sector_div(x, sectors_per_chunk); 1579 stripe = x; 1580 BUG_ON(x != stripe); 1581 1582 first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk 1583 + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf); 1584 sh = get_active_stripe(conf, sector_nr, pd_idx, 1); 1585 if (sh == NULL) { 1586 sh = get_active_stripe(conf, sector_nr, pd_idx, 0); 1587 /* make sure we don't swamp the stripe cache if someone else 1588 * is trying to get access 1589 */ 1590 set_current_state(TASK_UNINTERRUPTIBLE); 1591 schedule_timeout(1); 1592 } 1593 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0); 1594 spin_lock(&sh->lock); 1595 set_bit(STRIPE_SYNCING, &sh->state); 1596 clear_bit(STRIPE_INSYNC, &sh->state); 1597 spin_unlock(&sh->lock); 1598 1599 handle_stripe(sh); 1600 release_stripe(sh); 1601 1602 return STRIPE_SECTORS; 1603 } 1604 1605 /* 1606 * This is our raid5 kernel thread. 1607 * 1608 * We scan the hash table for stripes which can be handled now. 1609 * During the scan, completed stripes are saved for us by the interrupt 1610 * handler, so that they will not have to wait for our next wakeup. 1611 */ 1612 static void raid5d (mddev_t *mddev) 1613 { 1614 struct stripe_head *sh; 1615 raid5_conf_t *conf = mddev_to_conf(mddev); 1616 int handled; 1617 1618 PRINTK("+++ raid5d active\n"); 1619 1620 md_check_recovery(mddev); 1621 1622 handled = 0; 1623 spin_lock_irq(&conf->device_lock); 1624 while (1) { 1625 struct list_head *first; 1626 1627 if (conf->seq_flush - conf->seq_write > 0) { 1628 int seq = conf->seq_flush; 1629 bitmap_unplug(mddev->bitmap); 1630 conf->seq_write = seq; 1631 activate_bit_delay(conf); 1632 } 1633 1634 if (list_empty(&conf->handle_list) && 1635 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD && 1636 !blk_queue_plugged(mddev->queue) && 1637 !list_empty(&conf->delayed_list)) 1638 raid5_activate_delayed(conf); 1639 1640 if (list_empty(&conf->handle_list)) 1641 break; 1642 1643 first = conf->handle_list.next; 1644 sh = list_entry(first, struct stripe_head, lru); 1645 1646 list_del_init(first); 1647 atomic_inc(&sh->count); 1648 if (atomic_read(&sh->count)!= 1) 1649 BUG(); 1650 spin_unlock_irq(&conf->device_lock); 1651 1652 handled++; 1653 handle_stripe(sh); 1654 release_stripe(sh); 1655 1656 spin_lock_irq(&conf->device_lock); 1657 } 1658 PRINTK("%d stripes handled\n", handled); 1659 1660 spin_unlock_irq(&conf->device_lock); 1661 1662 unplug_slaves(mddev); 1663 1664 PRINTK("--- raid5d inactive\n"); 1665 } 1666 1667 static int run(mddev_t *mddev) 1668 { 1669 raid5_conf_t *conf; 1670 int raid_disk, memory; 1671 mdk_rdev_t *rdev; 1672 struct disk_info *disk; 1673 struct list_head *tmp; 1674 1675 if (mddev->level != 5 && mddev->level != 4) { 1676 printk("raid5: %s: raid level not set to 4/5 (%d)\n", mdname(mddev), mddev->level); 1677 return -EIO; 1678 } 1679 1680 mddev->private = kmalloc (sizeof (raid5_conf_t) 1681 + mddev->raid_disks * sizeof(struct disk_info), 1682 GFP_KERNEL); 1683 if ((conf = mddev->private) == NULL) 1684 goto abort; 1685 memset (conf, 0, sizeof (*conf) + mddev->raid_disks * sizeof(struct disk_info) ); 1686 conf->mddev = mddev; 1687 1688 if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL) 1689 goto abort; 1690 memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE); 1691 1692 spin_lock_init(&conf->device_lock); 1693 init_waitqueue_head(&conf->wait_for_stripe); 1694 init_waitqueue_head(&conf->wait_for_overlap); 1695 INIT_LIST_HEAD(&conf->handle_list); 1696 INIT_LIST_HEAD(&conf->delayed_list); 1697 INIT_LIST_HEAD(&conf->bitmap_list); 1698 INIT_LIST_HEAD(&conf->inactive_list); 1699 atomic_set(&conf->active_stripes, 0); 1700 atomic_set(&conf->preread_active_stripes, 0); 1701 1702 PRINTK("raid5: run(%s) called.\n", mdname(mddev)); 1703 1704 ITERATE_RDEV(mddev,rdev,tmp) { 1705 raid_disk = rdev->raid_disk; 1706 if (raid_disk >= mddev->raid_disks 1707 || raid_disk < 0) 1708 continue; 1709 disk = conf->disks + raid_disk; 1710 1711 disk->rdev = rdev; 1712 1713 if (rdev->in_sync) { 1714 char b[BDEVNAME_SIZE]; 1715 printk(KERN_INFO "raid5: device %s operational as raid" 1716 " disk %d\n", bdevname(rdev->bdev,b), 1717 raid_disk); 1718 conf->working_disks++; 1719 } 1720 } 1721 1722 conf->raid_disks = mddev->raid_disks; 1723 /* 1724 * 0 for a fully functional array, 1 for a degraded array. 1725 */ 1726 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks; 1727 conf->mddev = mddev; 1728 conf->chunk_size = mddev->chunk_size; 1729 conf->level = mddev->level; 1730 conf->algorithm = mddev->layout; 1731 conf->max_nr_stripes = NR_STRIPES; 1732 1733 /* device size must be a multiple of chunk size */ 1734 mddev->size &= ~(mddev->chunk_size/1024 -1); 1735 mddev->resync_max_sectors = mddev->size << 1; 1736 1737 if (!conf->chunk_size || conf->chunk_size % 4) { 1738 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", 1739 conf->chunk_size, mdname(mddev)); 1740 goto abort; 1741 } 1742 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) { 1743 printk(KERN_ERR 1744 "raid5: unsupported parity algorithm %d for %s\n", 1745 conf->algorithm, mdname(mddev)); 1746 goto abort; 1747 } 1748 if (mddev->degraded > 1) { 1749 printk(KERN_ERR "raid5: not enough operational devices for %s" 1750 " (%d/%d failed)\n", 1751 mdname(mddev), conf->failed_disks, conf->raid_disks); 1752 goto abort; 1753 } 1754 1755 if (mddev->degraded == 1 && 1756 mddev->recovery_cp != MaxSector) { 1757 printk(KERN_ERR 1758 "raid5: cannot start dirty degraded array for %s\n", 1759 mdname(mddev)); 1760 goto abort; 1761 } 1762 1763 { 1764 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5"); 1765 if (!mddev->thread) { 1766 printk(KERN_ERR 1767 "raid5: couldn't allocate thread for %s\n", 1768 mdname(mddev)); 1769 goto abort; 1770 } 1771 } 1772 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + 1773 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; 1774 if (grow_stripes(conf, conf->max_nr_stripes)) { 1775 printk(KERN_ERR 1776 "raid5: couldn't allocate %dkB for buffers\n", memory); 1777 shrink_stripes(conf); 1778 md_unregister_thread(mddev->thread); 1779 goto abort; 1780 } else 1781 printk(KERN_INFO "raid5: allocated %dkB for %s\n", 1782 memory, mdname(mddev)); 1783 1784 if (mddev->degraded == 0) 1785 printk("raid5: raid level %d set %s active with %d out of %d" 1786 " devices, algorithm %d\n", conf->level, mdname(mddev), 1787 mddev->raid_disks-mddev->degraded, mddev->raid_disks, 1788 conf->algorithm); 1789 else 1790 printk(KERN_ALERT "raid5: raid level %d set %s active with %d" 1791 " out of %d devices, algorithm %d\n", conf->level, 1792 mdname(mddev), mddev->raid_disks - mddev->degraded, 1793 mddev->raid_disks, conf->algorithm); 1794 1795 print_raid5_conf(conf); 1796 1797 /* read-ahead size must cover two whole stripes, which is 1798 * 2 * (n-1) * chunksize where 'n' is the number of raid devices 1799 */ 1800 { 1801 int stripe = (mddev->raid_disks-1) * mddev->chunk_size 1802 / PAGE_CACHE_SIZE; 1803 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 1804 mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 1805 } 1806 1807 /* Ok, everything is just fine now */ 1808 1809 if (mddev->bitmap) 1810 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; 1811 1812 mddev->queue->unplug_fn = raid5_unplug_device; 1813 mddev->queue->issue_flush_fn = raid5_issue_flush; 1814 1815 mddev->array_size = mddev->size * (mddev->raid_disks - 1); 1816 return 0; 1817 abort: 1818 if (conf) { 1819 print_raid5_conf(conf); 1820 if (conf->stripe_hashtbl) 1821 free_pages((unsigned long) conf->stripe_hashtbl, 1822 HASH_PAGES_ORDER); 1823 kfree(conf); 1824 } 1825 mddev->private = NULL; 1826 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); 1827 return -EIO; 1828 } 1829 1830 1831 1832 static int stop (mddev_t *mddev) 1833 { 1834 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1835 1836 md_unregister_thread(mddev->thread); 1837 mddev->thread = NULL; 1838 shrink_stripes(conf); 1839 free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER); 1840 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 1841 kfree(conf); 1842 mddev->private = NULL; 1843 return 0; 1844 } 1845 1846 #if RAID5_DEBUG 1847 static void print_sh (struct stripe_head *sh) 1848 { 1849 int i; 1850 1851 printk("sh %llu, pd_idx %d, state %ld.\n", 1852 (unsigned long long)sh->sector, sh->pd_idx, sh->state); 1853 printk("sh %llu, count %d.\n", 1854 (unsigned long long)sh->sector, atomic_read(&sh->count)); 1855 printk("sh %llu, ", (unsigned long long)sh->sector); 1856 for (i = 0; i < sh->raid_conf->raid_disks; i++) { 1857 printk("(cache%d: %p %ld) ", 1858 i, sh->dev[i].page, sh->dev[i].flags); 1859 } 1860 printk("\n"); 1861 } 1862 1863 static void printall (raid5_conf_t *conf) 1864 { 1865 struct stripe_head *sh; 1866 int i; 1867 1868 spin_lock_irq(&conf->device_lock); 1869 for (i = 0; i < NR_HASH; i++) { 1870 sh = conf->stripe_hashtbl[i]; 1871 for (; sh; sh = sh->hash_next) { 1872 if (sh->raid_conf != conf) 1873 continue; 1874 print_sh(sh); 1875 } 1876 } 1877 spin_unlock_irq(&conf->device_lock); 1878 } 1879 #endif 1880 1881 static void status (struct seq_file *seq, mddev_t *mddev) 1882 { 1883 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1884 int i; 1885 1886 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout); 1887 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks); 1888 for (i = 0; i < conf->raid_disks; i++) 1889 seq_printf (seq, "%s", 1890 conf->disks[i].rdev && 1891 conf->disks[i].rdev->in_sync ? "U" : "_"); 1892 seq_printf (seq, "]"); 1893 #if RAID5_DEBUG 1894 #define D(x) \ 1895 seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x)) 1896 printall(conf); 1897 #endif 1898 } 1899 1900 static void print_raid5_conf (raid5_conf_t *conf) 1901 { 1902 int i; 1903 struct disk_info *tmp; 1904 1905 printk("RAID5 conf printout:\n"); 1906 if (!conf) { 1907 printk("(conf==NULL)\n"); 1908 return; 1909 } 1910 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks, 1911 conf->working_disks, conf->failed_disks); 1912 1913 for (i = 0; i < conf->raid_disks; i++) { 1914 char b[BDEVNAME_SIZE]; 1915 tmp = conf->disks + i; 1916 if (tmp->rdev) 1917 printk(" disk %d, o:%d, dev:%s\n", 1918 i, !tmp->rdev->faulty, 1919 bdevname(tmp->rdev->bdev,b)); 1920 } 1921 } 1922 1923 static int raid5_spare_active(mddev_t *mddev) 1924 { 1925 int i; 1926 raid5_conf_t *conf = mddev->private; 1927 struct disk_info *tmp; 1928 1929 for (i = 0; i < conf->raid_disks; i++) { 1930 tmp = conf->disks + i; 1931 if (tmp->rdev 1932 && !tmp->rdev->faulty 1933 && !tmp->rdev->in_sync) { 1934 mddev->degraded--; 1935 conf->failed_disks--; 1936 conf->working_disks++; 1937 tmp->rdev->in_sync = 1; 1938 } 1939 } 1940 print_raid5_conf(conf); 1941 return 0; 1942 } 1943 1944 static int raid5_remove_disk(mddev_t *mddev, int number) 1945 { 1946 raid5_conf_t *conf = mddev->private; 1947 int err = 0; 1948 mdk_rdev_t *rdev; 1949 struct disk_info *p = conf->disks + number; 1950 1951 print_raid5_conf(conf); 1952 rdev = p->rdev; 1953 if (rdev) { 1954 if (rdev->in_sync || 1955 atomic_read(&rdev->nr_pending)) { 1956 err = -EBUSY; 1957 goto abort; 1958 } 1959 p->rdev = NULL; 1960 synchronize_rcu(); 1961 if (atomic_read(&rdev->nr_pending)) { 1962 /* lost the race, try later */ 1963 err = -EBUSY; 1964 p->rdev = rdev; 1965 } 1966 } 1967 abort: 1968 1969 print_raid5_conf(conf); 1970 return err; 1971 } 1972 1973 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 1974 { 1975 raid5_conf_t *conf = mddev->private; 1976 int found = 0; 1977 int disk; 1978 struct disk_info *p; 1979 1980 if (mddev->degraded > 1) 1981 /* no point adding a device */ 1982 return 0; 1983 1984 /* 1985 * find the disk ... 1986 */ 1987 for (disk=0; disk < mddev->raid_disks; disk++) 1988 if ((p=conf->disks + disk)->rdev == NULL) { 1989 rdev->in_sync = 0; 1990 rdev->raid_disk = disk; 1991 found = 1; 1992 if (rdev->saved_raid_disk != disk) 1993 conf->fullsync = 1; 1994 p->rdev = rdev; 1995 break; 1996 } 1997 print_raid5_conf(conf); 1998 return found; 1999 } 2000 2001 static int raid5_resize(mddev_t *mddev, sector_t sectors) 2002 { 2003 /* no resync is happening, and there is enough space 2004 * on all devices, so we can resize. 2005 * We need to make sure resync covers any new space. 2006 * If the array is shrinking we should possibly wait until 2007 * any io in the removed space completes, but it hardly seems 2008 * worth it. 2009 */ 2010 sectors &= ~((sector_t)mddev->chunk_size/512 - 1); 2011 mddev->array_size = (sectors * (mddev->raid_disks-1))>>1; 2012 set_capacity(mddev->gendisk, mddev->array_size << 1); 2013 mddev->changed = 1; 2014 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) { 2015 mddev->recovery_cp = mddev->size << 1; 2016 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 2017 } 2018 mddev->size = sectors /2; 2019 mddev->resync_max_sectors = sectors; 2020 return 0; 2021 } 2022 2023 static void raid5_quiesce(mddev_t *mddev, int state) 2024 { 2025 raid5_conf_t *conf = mddev_to_conf(mddev); 2026 2027 switch(state) { 2028 case 1: /* stop all writes */ 2029 spin_lock_irq(&conf->device_lock); 2030 conf->quiesce = 1; 2031 wait_event_lock_irq(conf->wait_for_stripe, 2032 atomic_read(&conf->active_stripes) == 0, 2033 conf->device_lock, /* nothing */); 2034 spin_unlock_irq(&conf->device_lock); 2035 break; 2036 2037 case 0: /* re-enable writes */ 2038 spin_lock_irq(&conf->device_lock); 2039 conf->quiesce = 0; 2040 wake_up(&conf->wait_for_stripe); 2041 spin_unlock_irq(&conf->device_lock); 2042 break; 2043 } 2044 if (mddev->thread) { 2045 if (mddev->bitmap) 2046 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; 2047 else 2048 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; 2049 md_wakeup_thread(mddev->thread); 2050 } 2051 } 2052 static mdk_personality_t raid5_personality= 2053 { 2054 .name = "raid5", 2055 .owner = THIS_MODULE, 2056 .make_request = make_request, 2057 .run = run, 2058 .stop = stop, 2059 .status = status, 2060 .error_handler = error, 2061 .hot_add_disk = raid5_add_disk, 2062 .hot_remove_disk= raid5_remove_disk, 2063 .spare_active = raid5_spare_active, 2064 .sync_request = sync_request, 2065 .resize = raid5_resize, 2066 .quiesce = raid5_quiesce, 2067 }; 2068 2069 static int __init raid5_init (void) 2070 { 2071 return register_md_personality (RAID5, &raid5_personality); 2072 } 2073 2074 static void raid5_exit (void) 2075 { 2076 unregister_md_personality (RAID5); 2077 } 2078 2079 module_init(raid5_init); 2080 module_exit(raid5_exit); 2081 MODULE_LICENSE("GPL"); 2082 MODULE_ALIAS("md-personality-4"); /* RAID5 */ 2083