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) < (conf->max_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) 268 < (conf->max_nr_stripes *3/4) 269 || !conf->inactive_blocked), 270 conf->device_lock, 271 unplug_slaves(conf->mddev); 272 ); 273 conf->inactive_blocked = 0; 274 } else 275 init_stripe(sh, sector, pd_idx); 276 } else { 277 if (atomic_read(&sh->count)) { 278 if (!list_empty(&sh->lru)) 279 BUG(); 280 } else { 281 if (!test_bit(STRIPE_HANDLE, &sh->state)) 282 atomic_inc(&conf->active_stripes); 283 if (list_empty(&sh->lru)) 284 BUG(); 285 list_del_init(&sh->lru); 286 } 287 } 288 } while (sh == NULL); 289 290 if (sh) 291 atomic_inc(&sh->count); 292 293 spin_unlock_irq(&conf->device_lock); 294 return sh; 295 } 296 297 static int grow_one_stripe(raid5_conf_t *conf) 298 { 299 struct stripe_head *sh; 300 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); 301 if (!sh) 302 return 0; 303 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev)); 304 sh->raid_conf = conf; 305 spin_lock_init(&sh->lock); 306 307 if (grow_buffers(sh, conf->raid_disks)) { 308 shrink_buffers(sh, conf->raid_disks); 309 kmem_cache_free(conf->slab_cache, sh); 310 return 0; 311 } 312 /* we just created an active stripe so... */ 313 atomic_set(&sh->count, 1); 314 atomic_inc(&conf->active_stripes); 315 INIT_LIST_HEAD(&sh->lru); 316 release_stripe(sh); 317 return 1; 318 } 319 320 static int grow_stripes(raid5_conf_t *conf, int num) 321 { 322 kmem_cache_t *sc; 323 int devs = conf->raid_disks; 324 325 sprintf(conf->cache_name, "raid5/%s", mdname(conf->mddev)); 326 327 sc = kmem_cache_create(conf->cache_name, 328 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 329 0, 0, NULL, NULL); 330 if (!sc) 331 return 1; 332 conf->slab_cache = sc; 333 while (num--) { 334 if (!grow_one_stripe(conf)) 335 return 1; 336 } 337 return 0; 338 } 339 340 static int drop_one_stripe(raid5_conf_t *conf) 341 { 342 struct stripe_head *sh; 343 344 spin_lock_irq(&conf->device_lock); 345 sh = get_free_stripe(conf); 346 spin_unlock_irq(&conf->device_lock); 347 if (!sh) 348 return 0; 349 if (atomic_read(&sh->count)) 350 BUG(); 351 shrink_buffers(sh, conf->raid_disks); 352 kmem_cache_free(conf->slab_cache, sh); 353 atomic_dec(&conf->active_stripes); 354 return 1; 355 } 356 357 static void shrink_stripes(raid5_conf_t *conf) 358 { 359 while (drop_one_stripe(conf)) 360 ; 361 362 kmem_cache_destroy(conf->slab_cache); 363 conf->slab_cache = NULL; 364 } 365 366 static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done, 367 int error) 368 { 369 struct stripe_head *sh = bi->bi_private; 370 raid5_conf_t *conf = sh->raid_conf; 371 int disks = conf->raid_disks, i; 372 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 373 374 if (bi->bi_size) 375 return 1; 376 377 for (i=0 ; i<disks; i++) 378 if (bi == &sh->dev[i].req) 379 break; 380 381 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n", 382 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 383 uptodate); 384 if (i == disks) { 385 BUG(); 386 return 0; 387 } 388 389 if (uptodate) { 390 #if 0 391 struct bio *bio; 392 unsigned long flags; 393 spin_lock_irqsave(&conf->device_lock, flags); 394 /* we can return a buffer if we bypassed the cache or 395 * if the top buffer is not in highmem. If there are 396 * multiple buffers, leave the extra work to 397 * handle_stripe 398 */ 399 buffer = sh->bh_read[i]; 400 if (buffer && 401 (!PageHighMem(buffer->b_page) 402 || buffer->b_page == bh->b_page ) 403 ) { 404 sh->bh_read[i] = buffer->b_reqnext; 405 buffer->b_reqnext = NULL; 406 } else 407 buffer = NULL; 408 spin_unlock_irqrestore(&conf->device_lock, flags); 409 if (sh->bh_page[i]==bh->b_page) 410 set_buffer_uptodate(bh); 411 if (buffer) { 412 if (buffer->b_page != bh->b_page) 413 memcpy(buffer->b_data, bh->b_data, bh->b_size); 414 buffer->b_end_io(buffer, 1); 415 } 416 #else 417 set_bit(R5_UPTODATE, &sh->dev[i].flags); 418 #endif 419 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 420 printk("R5: read error corrected!!\n"); 421 clear_bit(R5_ReadError, &sh->dev[i].flags); 422 clear_bit(R5_ReWrite, &sh->dev[i].flags); 423 } 424 if (atomic_read(&conf->disks[i].rdev->read_errors)) 425 atomic_set(&conf->disks[i].rdev->read_errors, 0); 426 } else { 427 int retry = 0; 428 clear_bit(R5_UPTODATE, &sh->dev[i].flags); 429 atomic_inc(&conf->disks[i].rdev->read_errors); 430 if (conf->mddev->degraded) 431 printk("R5: read error not correctable.\n"); 432 else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) 433 /* Oh, no!!! */ 434 printk("R5: read error NOT corrected!!\n"); 435 else if (atomic_read(&conf->disks[i].rdev->read_errors) 436 > conf->max_nr_stripes) 437 printk("raid5: Too many read errors, failing device.\n"); 438 else 439 retry = 1; 440 if (retry) 441 set_bit(R5_ReadError, &sh->dev[i].flags); 442 else { 443 clear_bit(R5_ReadError, &sh->dev[i].flags); 444 clear_bit(R5_ReWrite, &sh->dev[i].flags); 445 md_error(conf->mddev, conf->disks[i].rdev); 446 } 447 } 448 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 449 #if 0 450 /* must restore b_page before unlocking buffer... */ 451 if (sh->bh_page[i] != bh->b_page) { 452 bh->b_page = sh->bh_page[i]; 453 bh->b_data = page_address(bh->b_page); 454 clear_buffer_uptodate(bh); 455 } 456 #endif 457 clear_bit(R5_LOCKED, &sh->dev[i].flags); 458 set_bit(STRIPE_HANDLE, &sh->state); 459 release_stripe(sh); 460 return 0; 461 } 462 463 static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, 464 int error) 465 { 466 struct stripe_head *sh = bi->bi_private; 467 raid5_conf_t *conf = sh->raid_conf; 468 int disks = conf->raid_disks, i; 469 unsigned long flags; 470 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 471 472 if (bi->bi_size) 473 return 1; 474 475 for (i=0 ; i<disks; i++) 476 if (bi == &sh->dev[i].req) 477 break; 478 479 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n", 480 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 481 uptodate); 482 if (i == disks) { 483 BUG(); 484 return 0; 485 } 486 487 spin_lock_irqsave(&conf->device_lock, flags); 488 if (!uptodate) 489 md_error(conf->mddev, conf->disks[i].rdev); 490 491 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 492 493 clear_bit(R5_LOCKED, &sh->dev[i].flags); 494 set_bit(STRIPE_HANDLE, &sh->state); 495 __release_stripe(conf, sh); 496 spin_unlock_irqrestore(&conf->device_lock, flags); 497 return 0; 498 } 499 500 501 static sector_t compute_blocknr(struct stripe_head *sh, int i); 502 503 static void raid5_build_block (struct stripe_head *sh, int i) 504 { 505 struct r5dev *dev = &sh->dev[i]; 506 507 bio_init(&dev->req); 508 dev->req.bi_io_vec = &dev->vec; 509 dev->req.bi_vcnt++; 510 dev->req.bi_max_vecs++; 511 dev->vec.bv_page = dev->page; 512 dev->vec.bv_len = STRIPE_SIZE; 513 dev->vec.bv_offset = 0; 514 515 dev->req.bi_sector = sh->sector; 516 dev->req.bi_private = sh; 517 518 dev->flags = 0; 519 if (i != sh->pd_idx) 520 dev->sector = compute_blocknr(sh, i); 521 } 522 523 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 524 { 525 char b[BDEVNAME_SIZE]; 526 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 527 PRINTK("raid5: error called\n"); 528 529 if (!test_bit(Faulty, &rdev->flags)) { 530 mddev->sb_dirty = 1; 531 if (test_bit(In_sync, &rdev->flags)) { 532 conf->working_disks--; 533 mddev->degraded++; 534 conf->failed_disks++; 535 clear_bit(In_sync, &rdev->flags); 536 /* 537 * if recovery was running, make sure it aborts. 538 */ 539 set_bit(MD_RECOVERY_ERR, &mddev->recovery); 540 } 541 set_bit(Faulty, &rdev->flags); 542 printk (KERN_ALERT 543 "raid5: Disk failure on %s, disabling device." 544 " Operation continuing on %d devices\n", 545 bdevname(rdev->bdev,b), conf->working_disks); 546 } 547 } 548 549 /* 550 * Input: a 'big' sector number, 551 * Output: index of the data and parity disk, and the sector # in them. 552 */ 553 static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks, 554 unsigned int data_disks, unsigned int * dd_idx, 555 unsigned int * pd_idx, raid5_conf_t *conf) 556 { 557 long stripe; 558 unsigned long chunk_number; 559 unsigned int chunk_offset; 560 sector_t new_sector; 561 int sectors_per_chunk = conf->chunk_size >> 9; 562 563 /* First compute the information on this sector */ 564 565 /* 566 * Compute the chunk number and the sector offset inside the chunk 567 */ 568 chunk_offset = sector_div(r_sector, sectors_per_chunk); 569 chunk_number = r_sector; 570 BUG_ON(r_sector != chunk_number); 571 572 /* 573 * Compute the stripe number 574 */ 575 stripe = chunk_number / data_disks; 576 577 /* 578 * Compute the data disk and parity disk indexes inside the stripe 579 */ 580 *dd_idx = chunk_number % data_disks; 581 582 /* 583 * Select the parity disk based on the user selected algorithm. 584 */ 585 if (conf->level == 4) 586 *pd_idx = data_disks; 587 else switch (conf->algorithm) { 588 case ALGORITHM_LEFT_ASYMMETRIC: 589 *pd_idx = data_disks - stripe % raid_disks; 590 if (*dd_idx >= *pd_idx) 591 (*dd_idx)++; 592 break; 593 case ALGORITHM_RIGHT_ASYMMETRIC: 594 *pd_idx = stripe % raid_disks; 595 if (*dd_idx >= *pd_idx) 596 (*dd_idx)++; 597 break; 598 case ALGORITHM_LEFT_SYMMETRIC: 599 *pd_idx = data_disks - stripe % raid_disks; 600 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 601 break; 602 case ALGORITHM_RIGHT_SYMMETRIC: 603 *pd_idx = stripe % raid_disks; 604 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 605 break; 606 default: 607 printk("raid5: unsupported algorithm %d\n", 608 conf->algorithm); 609 } 610 611 /* 612 * Finally, compute the new sector number 613 */ 614 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; 615 return new_sector; 616 } 617 618 619 static sector_t compute_blocknr(struct stripe_head *sh, int i) 620 { 621 raid5_conf_t *conf = sh->raid_conf; 622 int raid_disks = conf->raid_disks, data_disks = raid_disks - 1; 623 sector_t new_sector = sh->sector, check; 624 int sectors_per_chunk = conf->chunk_size >> 9; 625 sector_t stripe; 626 int chunk_offset; 627 int chunk_number, dummy1, dummy2, dd_idx = i; 628 sector_t r_sector; 629 630 chunk_offset = sector_div(new_sector, sectors_per_chunk); 631 stripe = new_sector; 632 BUG_ON(new_sector != stripe); 633 634 635 switch (conf->algorithm) { 636 case ALGORITHM_LEFT_ASYMMETRIC: 637 case ALGORITHM_RIGHT_ASYMMETRIC: 638 if (i > sh->pd_idx) 639 i--; 640 break; 641 case ALGORITHM_LEFT_SYMMETRIC: 642 case ALGORITHM_RIGHT_SYMMETRIC: 643 if (i < sh->pd_idx) 644 i += raid_disks; 645 i -= (sh->pd_idx + 1); 646 break; 647 default: 648 printk("raid5: unsupported algorithm %d\n", 649 conf->algorithm); 650 } 651 652 chunk_number = stripe * data_disks + i; 653 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; 654 655 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf); 656 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) { 657 printk("compute_blocknr: map not correct\n"); 658 return 0; 659 } 660 return r_sector; 661 } 662 663 664 665 /* 666 * Copy data between a page in the stripe cache, and a bio. 667 * There are no alignment or size guarantees between the page or the 668 * bio except that there is some overlap. 669 * All iovecs in the bio must be considered. 670 */ 671 static void copy_data(int frombio, struct bio *bio, 672 struct page *page, 673 sector_t sector) 674 { 675 char *pa = page_address(page); 676 struct bio_vec *bvl; 677 int i; 678 int page_offset; 679 680 if (bio->bi_sector >= sector) 681 page_offset = (signed)(bio->bi_sector - sector) * 512; 682 else 683 page_offset = (signed)(sector - bio->bi_sector) * -512; 684 bio_for_each_segment(bvl, bio, i) { 685 int len = bio_iovec_idx(bio,i)->bv_len; 686 int clen; 687 int b_offset = 0; 688 689 if (page_offset < 0) { 690 b_offset = -page_offset; 691 page_offset += b_offset; 692 len -= b_offset; 693 } 694 695 if (len > 0 && page_offset + len > STRIPE_SIZE) 696 clen = STRIPE_SIZE - page_offset; 697 else clen = len; 698 699 if (clen > 0) { 700 char *ba = __bio_kmap_atomic(bio, i, KM_USER0); 701 if (frombio) 702 memcpy(pa+page_offset, ba+b_offset, clen); 703 else 704 memcpy(ba+b_offset, pa+page_offset, clen); 705 __bio_kunmap_atomic(ba, KM_USER0); 706 } 707 if (clen < len) /* hit end of page */ 708 break; 709 page_offset += len; 710 } 711 } 712 713 #define check_xor() do { \ 714 if (count == MAX_XOR_BLOCKS) { \ 715 xor_block(count, STRIPE_SIZE, ptr); \ 716 count = 1; \ 717 } \ 718 } while(0) 719 720 721 static void compute_block(struct stripe_head *sh, int dd_idx) 722 { 723 raid5_conf_t *conf = sh->raid_conf; 724 int i, count, disks = conf->raid_disks; 725 void *ptr[MAX_XOR_BLOCKS], *p; 726 727 PRINTK("compute_block, stripe %llu, idx %d\n", 728 (unsigned long long)sh->sector, dd_idx); 729 730 ptr[0] = page_address(sh->dev[dd_idx].page); 731 memset(ptr[0], 0, STRIPE_SIZE); 732 count = 1; 733 for (i = disks ; i--; ) { 734 if (i == dd_idx) 735 continue; 736 p = page_address(sh->dev[i].page); 737 if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) 738 ptr[count++] = p; 739 else 740 printk("compute_block() %d, stripe %llu, %d" 741 " not present\n", dd_idx, 742 (unsigned long long)sh->sector, i); 743 744 check_xor(); 745 } 746 if (count != 1) 747 xor_block(count, STRIPE_SIZE, ptr); 748 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 749 } 750 751 static void compute_parity(struct stripe_head *sh, int method) 752 { 753 raid5_conf_t *conf = sh->raid_conf; 754 int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count; 755 void *ptr[MAX_XOR_BLOCKS]; 756 struct bio *chosen; 757 758 PRINTK("compute_parity, stripe %llu, method %d\n", 759 (unsigned long long)sh->sector, method); 760 761 count = 1; 762 ptr[0] = page_address(sh->dev[pd_idx].page); 763 switch(method) { 764 case READ_MODIFY_WRITE: 765 if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags)) 766 BUG(); 767 for (i=disks ; i-- ;) { 768 if (i==pd_idx) 769 continue; 770 if (sh->dev[i].towrite && 771 test_bit(R5_UPTODATE, &sh->dev[i].flags)) { 772 ptr[count++] = page_address(sh->dev[i].page); 773 chosen = sh->dev[i].towrite; 774 sh->dev[i].towrite = NULL; 775 776 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 777 wake_up(&conf->wait_for_overlap); 778 779 if (sh->dev[i].written) BUG(); 780 sh->dev[i].written = chosen; 781 check_xor(); 782 } 783 } 784 break; 785 case RECONSTRUCT_WRITE: 786 memset(ptr[0], 0, STRIPE_SIZE); 787 for (i= disks; i-- ;) 788 if (i!=pd_idx && sh->dev[i].towrite) { 789 chosen = sh->dev[i].towrite; 790 sh->dev[i].towrite = NULL; 791 792 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 793 wake_up(&conf->wait_for_overlap); 794 795 if (sh->dev[i].written) BUG(); 796 sh->dev[i].written = chosen; 797 } 798 break; 799 case CHECK_PARITY: 800 break; 801 } 802 if (count>1) { 803 xor_block(count, STRIPE_SIZE, ptr); 804 count = 1; 805 } 806 807 for (i = disks; i--;) 808 if (sh->dev[i].written) { 809 sector_t sector = sh->dev[i].sector; 810 struct bio *wbi = sh->dev[i].written; 811 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { 812 copy_data(1, wbi, sh->dev[i].page, sector); 813 wbi = r5_next_bio(wbi, sector); 814 } 815 816 set_bit(R5_LOCKED, &sh->dev[i].flags); 817 set_bit(R5_UPTODATE, &sh->dev[i].flags); 818 } 819 820 switch(method) { 821 case RECONSTRUCT_WRITE: 822 case CHECK_PARITY: 823 for (i=disks; i--;) 824 if (i != pd_idx) { 825 ptr[count++] = page_address(sh->dev[i].page); 826 check_xor(); 827 } 828 break; 829 case READ_MODIFY_WRITE: 830 for (i = disks; i--;) 831 if (sh->dev[i].written) { 832 ptr[count++] = page_address(sh->dev[i].page); 833 check_xor(); 834 } 835 } 836 if (count != 1) 837 xor_block(count, STRIPE_SIZE, ptr); 838 839 if (method != CHECK_PARITY) { 840 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 841 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 842 } else 843 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 844 } 845 846 /* 847 * Each stripe/dev can have one or more bion attached. 848 * toread/towrite point to the first in a chain. 849 * The bi_next chain must be in order. 850 */ 851 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) 852 { 853 struct bio **bip; 854 raid5_conf_t *conf = sh->raid_conf; 855 int firstwrite=0; 856 857 PRINTK("adding bh b#%llu to stripe s#%llu\n", 858 (unsigned long long)bi->bi_sector, 859 (unsigned long long)sh->sector); 860 861 862 spin_lock(&sh->lock); 863 spin_lock_irq(&conf->device_lock); 864 if (forwrite) { 865 bip = &sh->dev[dd_idx].towrite; 866 if (*bip == NULL && sh->dev[dd_idx].written == NULL) 867 firstwrite = 1; 868 } else 869 bip = &sh->dev[dd_idx].toread; 870 while (*bip && (*bip)->bi_sector < bi->bi_sector) { 871 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) 872 goto overlap; 873 bip = & (*bip)->bi_next; 874 } 875 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) 876 goto overlap; 877 878 if (*bip && bi->bi_next && (*bip) != bi->bi_next) 879 BUG(); 880 if (*bip) 881 bi->bi_next = *bip; 882 *bip = bi; 883 bi->bi_phys_segments ++; 884 spin_unlock_irq(&conf->device_lock); 885 spin_unlock(&sh->lock); 886 887 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n", 888 (unsigned long long)bi->bi_sector, 889 (unsigned long long)sh->sector, dd_idx); 890 891 if (conf->mddev->bitmap && firstwrite) { 892 sh->bm_seq = conf->seq_write; 893 bitmap_startwrite(conf->mddev->bitmap, sh->sector, 894 STRIPE_SECTORS, 0); 895 set_bit(STRIPE_BIT_DELAY, &sh->state); 896 } 897 898 if (forwrite) { 899 /* check if page is covered */ 900 sector_t sector = sh->dev[dd_idx].sector; 901 for (bi=sh->dev[dd_idx].towrite; 902 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && 903 bi && bi->bi_sector <= sector; 904 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { 905 if (bi->bi_sector + (bi->bi_size>>9) >= sector) 906 sector = bi->bi_sector + (bi->bi_size>>9); 907 } 908 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) 909 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); 910 } 911 return 1; 912 913 overlap: 914 set_bit(R5_Overlap, &sh->dev[dd_idx].flags); 915 spin_unlock_irq(&conf->device_lock); 916 spin_unlock(&sh->lock); 917 return 0; 918 } 919 920 921 /* 922 * handle_stripe - do things to a stripe. 923 * 924 * We lock the stripe and then examine the state of various bits 925 * to see what needs to be done. 926 * Possible results: 927 * return some read request which now have data 928 * return some write requests which are safely on disc 929 * schedule a read on some buffers 930 * schedule a write of some buffers 931 * return confirmation of parity correctness 932 * 933 * Parity calculations are done inside the stripe lock 934 * buffers are taken off read_list or write_list, and bh_cache buffers 935 * get BH_Lock set before the stripe lock is released. 936 * 937 */ 938 939 static void handle_stripe(struct stripe_head *sh) 940 { 941 raid5_conf_t *conf = sh->raid_conf; 942 int disks = conf->raid_disks; 943 struct bio *return_bi= NULL; 944 struct bio *bi; 945 int i; 946 int syncing; 947 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0; 948 int non_overwrite = 0; 949 int failed_num=0; 950 struct r5dev *dev; 951 952 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n", 953 (unsigned long long)sh->sector, atomic_read(&sh->count), 954 sh->pd_idx); 955 956 spin_lock(&sh->lock); 957 clear_bit(STRIPE_HANDLE, &sh->state); 958 clear_bit(STRIPE_DELAYED, &sh->state); 959 960 syncing = test_bit(STRIPE_SYNCING, &sh->state); 961 /* Now to look around and see what can be done */ 962 963 for (i=disks; i--; ) { 964 mdk_rdev_t *rdev; 965 dev = &sh->dev[i]; 966 clear_bit(R5_Insync, &dev->flags); 967 clear_bit(R5_Syncio, &dev->flags); 968 969 PRINTK("check %d: state 0x%lx read %p write %p written %p\n", 970 i, dev->flags, dev->toread, dev->towrite, dev->written); 971 /* maybe we can reply to a read */ 972 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { 973 struct bio *rbi, *rbi2; 974 PRINTK("Return read for disc %d\n", i); 975 spin_lock_irq(&conf->device_lock); 976 rbi = dev->toread; 977 dev->toread = NULL; 978 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 979 wake_up(&conf->wait_for_overlap); 980 spin_unlock_irq(&conf->device_lock); 981 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { 982 copy_data(0, rbi, dev->page, dev->sector); 983 rbi2 = r5_next_bio(rbi, dev->sector); 984 spin_lock_irq(&conf->device_lock); 985 if (--rbi->bi_phys_segments == 0) { 986 rbi->bi_next = return_bi; 987 return_bi = rbi; 988 } 989 spin_unlock_irq(&conf->device_lock); 990 rbi = rbi2; 991 } 992 } 993 994 /* now count some things */ 995 if (test_bit(R5_LOCKED, &dev->flags)) locked++; 996 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++; 997 998 999 if (dev->toread) to_read++; 1000 if (dev->towrite) { 1001 to_write++; 1002 if (!test_bit(R5_OVERWRITE, &dev->flags)) 1003 non_overwrite++; 1004 } 1005 if (dev->written) written++; 1006 rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */ 1007 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 1008 /* The ReadError flag wil just be confusing now */ 1009 clear_bit(R5_ReadError, &dev->flags); 1010 clear_bit(R5_ReWrite, &dev->flags); 1011 } 1012 if (!rdev || !test_bit(In_sync, &rdev->flags) 1013 || test_bit(R5_ReadError, &dev->flags)) { 1014 failed++; 1015 failed_num = i; 1016 } else 1017 set_bit(R5_Insync, &dev->flags); 1018 } 1019 PRINTK("locked=%d uptodate=%d to_read=%d" 1020 " to_write=%d failed=%d failed_num=%d\n", 1021 locked, uptodate, to_read, to_write, failed, failed_num); 1022 /* check if the array has lost two devices and, if so, some requests might 1023 * need to be failed 1024 */ 1025 if (failed > 1 && to_read+to_write+written) { 1026 for (i=disks; i--; ) { 1027 int bitmap_end = 0; 1028 1029 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1030 mdk_rdev_t *rdev = conf->disks[i].rdev; 1031 if (rdev && test_bit(In_sync, &rdev->flags)) 1032 /* multiple read failures in one stripe */ 1033 md_error(conf->mddev, rdev); 1034 } 1035 1036 spin_lock_irq(&conf->device_lock); 1037 /* fail all writes first */ 1038 bi = sh->dev[i].towrite; 1039 sh->dev[i].towrite = NULL; 1040 if (bi) { to_write--; bitmap_end = 1; } 1041 1042 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1043 wake_up(&conf->wait_for_overlap); 1044 1045 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 1046 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 1047 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1048 if (--bi->bi_phys_segments == 0) { 1049 md_write_end(conf->mddev); 1050 bi->bi_next = return_bi; 1051 return_bi = bi; 1052 } 1053 bi = nextbi; 1054 } 1055 /* and fail all 'written' */ 1056 bi = sh->dev[i].written; 1057 sh->dev[i].written = NULL; 1058 if (bi) bitmap_end = 1; 1059 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { 1060 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 1061 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1062 if (--bi->bi_phys_segments == 0) { 1063 md_write_end(conf->mddev); 1064 bi->bi_next = return_bi; 1065 return_bi = bi; 1066 } 1067 bi = bi2; 1068 } 1069 1070 /* fail any reads if this device is non-operational */ 1071 if (!test_bit(R5_Insync, &sh->dev[i].flags) || 1072 test_bit(R5_ReadError, &sh->dev[i].flags)) { 1073 bi = sh->dev[i].toread; 1074 sh->dev[i].toread = NULL; 1075 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1076 wake_up(&conf->wait_for_overlap); 1077 if (bi) to_read--; 1078 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 1079 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 1080 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1081 if (--bi->bi_phys_segments == 0) { 1082 bi->bi_next = return_bi; 1083 return_bi = bi; 1084 } 1085 bi = nextbi; 1086 } 1087 } 1088 spin_unlock_irq(&conf->device_lock); 1089 if (bitmap_end) 1090 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1091 STRIPE_SECTORS, 0, 0); 1092 } 1093 } 1094 if (failed > 1 && syncing) { 1095 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 1096 clear_bit(STRIPE_SYNCING, &sh->state); 1097 syncing = 0; 1098 } 1099 1100 /* might be able to return some write requests if the parity block 1101 * is safe, or on a failed drive 1102 */ 1103 dev = &sh->dev[sh->pd_idx]; 1104 if ( written && 1105 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) && 1106 test_bit(R5_UPTODATE, &dev->flags)) 1107 || (failed == 1 && failed_num == sh->pd_idx)) 1108 ) { 1109 /* any written block on an uptodate or failed drive can be returned. 1110 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but 1111 * never LOCKED, so we don't need to test 'failed' directly. 1112 */ 1113 for (i=disks; i--; ) 1114 if (sh->dev[i].written) { 1115 dev = &sh->dev[i]; 1116 if (!test_bit(R5_LOCKED, &dev->flags) && 1117 test_bit(R5_UPTODATE, &dev->flags) ) { 1118 /* We can return any write requests */ 1119 struct bio *wbi, *wbi2; 1120 int bitmap_end = 0; 1121 PRINTK("Return write for disc %d\n", i); 1122 spin_lock_irq(&conf->device_lock); 1123 wbi = dev->written; 1124 dev->written = NULL; 1125 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { 1126 wbi2 = r5_next_bio(wbi, dev->sector); 1127 if (--wbi->bi_phys_segments == 0) { 1128 md_write_end(conf->mddev); 1129 wbi->bi_next = return_bi; 1130 return_bi = wbi; 1131 } 1132 wbi = wbi2; 1133 } 1134 if (dev->towrite == NULL) 1135 bitmap_end = 1; 1136 spin_unlock_irq(&conf->device_lock); 1137 if (bitmap_end) 1138 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1139 STRIPE_SECTORS, 1140 !test_bit(STRIPE_DEGRADED, &sh->state), 0); 1141 } 1142 } 1143 } 1144 1145 /* Now we might consider reading some blocks, either to check/generate 1146 * parity, or to satisfy requests 1147 * or to load a block that is being partially written. 1148 */ 1149 if (to_read || non_overwrite || (syncing && (uptodate < disks))) { 1150 for (i=disks; i--;) { 1151 dev = &sh->dev[i]; 1152 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1153 (dev->toread || 1154 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 1155 syncing || 1156 (failed && (sh->dev[failed_num].toread || 1157 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags)))) 1158 ) 1159 ) { 1160 /* we would like to get this block, possibly 1161 * by computing it, but we might not be able to 1162 */ 1163 if (uptodate == disks-1) { 1164 PRINTK("Computing block %d\n", i); 1165 compute_block(sh, i); 1166 uptodate++; 1167 } else if (test_bit(R5_Insync, &dev->flags)) { 1168 set_bit(R5_LOCKED, &dev->flags); 1169 set_bit(R5_Wantread, &dev->flags); 1170 #if 0 1171 /* if I am just reading this block and we don't have 1172 a failed drive, or any pending writes then sidestep the cache */ 1173 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext && 1174 ! syncing && !failed && !to_write) { 1175 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page; 1176 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data; 1177 } 1178 #endif 1179 locked++; 1180 PRINTK("Reading block %d (sync=%d)\n", 1181 i, syncing); 1182 if (syncing) 1183 md_sync_acct(conf->disks[i].rdev->bdev, 1184 STRIPE_SECTORS); 1185 } 1186 } 1187 } 1188 set_bit(STRIPE_HANDLE, &sh->state); 1189 } 1190 1191 /* now to consider writing and what else, if anything should be read */ 1192 if (to_write) { 1193 int rmw=0, rcw=0; 1194 for (i=disks ; i--;) { 1195 /* would I have to read this buffer for read_modify_write */ 1196 dev = &sh->dev[i]; 1197 if ((dev->towrite || i == sh->pd_idx) && 1198 (!test_bit(R5_LOCKED, &dev->flags) 1199 #if 0 1200 || sh->bh_page[i]!=bh->b_page 1201 #endif 1202 ) && 1203 !test_bit(R5_UPTODATE, &dev->flags)) { 1204 if (test_bit(R5_Insync, &dev->flags) 1205 /* && !(!mddev->insync && i == sh->pd_idx) */ 1206 ) 1207 rmw++; 1208 else rmw += 2*disks; /* cannot read it */ 1209 } 1210 /* Would I have to read this buffer for reconstruct_write */ 1211 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 1212 (!test_bit(R5_LOCKED, &dev->flags) 1213 #if 0 1214 || sh->bh_page[i] != bh->b_page 1215 #endif 1216 ) && 1217 !test_bit(R5_UPTODATE, &dev->flags)) { 1218 if (test_bit(R5_Insync, &dev->flags)) rcw++; 1219 else rcw += 2*disks; 1220 } 1221 } 1222 PRINTK("for sector %llu, rmw=%d rcw=%d\n", 1223 (unsigned long long)sh->sector, rmw, rcw); 1224 set_bit(STRIPE_HANDLE, &sh->state); 1225 if (rmw < rcw && rmw > 0) 1226 /* prefer read-modify-write, but need to get some data */ 1227 for (i=disks; i--;) { 1228 dev = &sh->dev[i]; 1229 if ((dev->towrite || i == sh->pd_idx) && 1230 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1231 test_bit(R5_Insync, &dev->flags)) { 1232 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1233 { 1234 PRINTK("Read_old block %d for r-m-w\n", i); 1235 set_bit(R5_LOCKED, &dev->flags); 1236 set_bit(R5_Wantread, &dev->flags); 1237 locked++; 1238 } else { 1239 set_bit(STRIPE_DELAYED, &sh->state); 1240 set_bit(STRIPE_HANDLE, &sh->state); 1241 } 1242 } 1243 } 1244 if (rcw <= rmw && rcw > 0) 1245 /* want reconstruct write, but need to get some data */ 1246 for (i=disks; i--;) { 1247 dev = &sh->dev[i]; 1248 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 1249 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1250 test_bit(R5_Insync, &dev->flags)) { 1251 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1252 { 1253 PRINTK("Read_old block %d for Reconstruct\n", i); 1254 set_bit(R5_LOCKED, &dev->flags); 1255 set_bit(R5_Wantread, &dev->flags); 1256 locked++; 1257 } else { 1258 set_bit(STRIPE_DELAYED, &sh->state); 1259 set_bit(STRIPE_HANDLE, &sh->state); 1260 } 1261 } 1262 } 1263 /* now if nothing is locked, and if we have enough data, we can start a write request */ 1264 if (locked == 0 && (rcw == 0 ||rmw == 0) && 1265 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 1266 PRINTK("Computing parity...\n"); 1267 compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE); 1268 /* now every locked buffer is ready to be written */ 1269 for (i=disks; i--;) 1270 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { 1271 PRINTK("Writing block %d\n", i); 1272 locked++; 1273 set_bit(R5_Wantwrite, &sh->dev[i].flags); 1274 if (!test_bit(R5_Insync, &sh->dev[i].flags) 1275 || (i==sh->pd_idx && failed == 0)) 1276 set_bit(STRIPE_INSYNC, &sh->state); 1277 } 1278 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 1279 atomic_dec(&conf->preread_active_stripes); 1280 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 1281 md_wakeup_thread(conf->mddev->thread); 1282 } 1283 } 1284 } 1285 1286 /* maybe we need to check and possibly fix the parity for this stripe 1287 * Any reads will already have been scheduled, so we just see if enough data 1288 * is available 1289 */ 1290 if (syncing && locked == 0 && 1291 !test_bit(STRIPE_INSYNC, &sh->state) && failed <= 1) { 1292 set_bit(STRIPE_HANDLE, &sh->state); 1293 if (failed == 0) { 1294 char *pagea; 1295 if (uptodate != disks) 1296 BUG(); 1297 compute_parity(sh, CHECK_PARITY); 1298 uptodate--; 1299 pagea = page_address(sh->dev[sh->pd_idx].page); 1300 if ((*(u32*)pagea) == 0 && 1301 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) { 1302 /* parity is correct (on disc, not in buffer any more) */ 1303 set_bit(STRIPE_INSYNC, &sh->state); 1304 } else { 1305 conf->mddev->resync_mismatches += STRIPE_SECTORS; 1306 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 1307 /* don't try to repair!! */ 1308 set_bit(STRIPE_INSYNC, &sh->state); 1309 } 1310 } 1311 if (!test_bit(STRIPE_INSYNC, &sh->state)) { 1312 if (failed==0) 1313 failed_num = sh->pd_idx; 1314 /* should be able to compute the missing block and write it to spare */ 1315 if (!test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)) { 1316 if (uptodate+1 != disks) 1317 BUG(); 1318 compute_block(sh, failed_num); 1319 uptodate++; 1320 } 1321 if (uptodate != disks) 1322 BUG(); 1323 dev = &sh->dev[failed_num]; 1324 set_bit(R5_LOCKED, &dev->flags); 1325 set_bit(R5_Wantwrite, &dev->flags); 1326 clear_bit(STRIPE_DEGRADED, &sh->state); 1327 locked++; 1328 set_bit(STRIPE_INSYNC, &sh->state); 1329 set_bit(R5_Syncio, &dev->flags); 1330 } 1331 } 1332 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 1333 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 1334 clear_bit(STRIPE_SYNCING, &sh->state); 1335 } 1336 1337 /* If the failed drive is just a ReadError, then we might need to progress 1338 * the repair/check process 1339 */ 1340 if (failed == 1 && ! conf->mddev->ro && 1341 test_bit(R5_ReadError, &sh->dev[failed_num].flags) 1342 && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags) 1343 && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags) 1344 ) { 1345 dev = &sh->dev[failed_num]; 1346 if (!test_bit(R5_ReWrite, &dev->flags)) { 1347 set_bit(R5_Wantwrite, &dev->flags); 1348 set_bit(R5_ReWrite, &dev->flags); 1349 set_bit(R5_LOCKED, &dev->flags); 1350 } else { 1351 /* let's read it back */ 1352 set_bit(R5_Wantread, &dev->flags); 1353 set_bit(R5_LOCKED, &dev->flags); 1354 } 1355 } 1356 1357 spin_unlock(&sh->lock); 1358 1359 while ((bi=return_bi)) { 1360 int bytes = bi->bi_size; 1361 1362 return_bi = bi->bi_next; 1363 bi->bi_next = NULL; 1364 bi->bi_size = 0; 1365 bi->bi_end_io(bi, bytes, 0); 1366 } 1367 for (i=disks; i-- ;) { 1368 int rw; 1369 struct bio *bi; 1370 mdk_rdev_t *rdev; 1371 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 1372 rw = 1; 1373 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 1374 rw = 0; 1375 else 1376 continue; 1377 1378 bi = &sh->dev[i].req; 1379 1380 bi->bi_rw = rw; 1381 if (rw) 1382 bi->bi_end_io = raid5_end_write_request; 1383 else 1384 bi->bi_end_io = raid5_end_read_request; 1385 1386 rcu_read_lock(); 1387 rdev = rcu_dereference(conf->disks[i].rdev); 1388 if (rdev && test_bit(Faulty, &rdev->flags)) 1389 rdev = NULL; 1390 if (rdev) 1391 atomic_inc(&rdev->nr_pending); 1392 rcu_read_unlock(); 1393 1394 if (rdev) { 1395 if (test_bit(R5_Syncio, &sh->dev[i].flags)) 1396 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 1397 1398 bi->bi_bdev = rdev->bdev; 1399 PRINTK("for %llu schedule op %ld on disc %d\n", 1400 (unsigned long long)sh->sector, bi->bi_rw, i); 1401 atomic_inc(&sh->count); 1402 bi->bi_sector = sh->sector + rdev->data_offset; 1403 bi->bi_flags = 1 << BIO_UPTODATE; 1404 bi->bi_vcnt = 1; 1405 bi->bi_max_vecs = 1; 1406 bi->bi_idx = 0; 1407 bi->bi_io_vec = &sh->dev[i].vec; 1408 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 1409 bi->bi_io_vec[0].bv_offset = 0; 1410 bi->bi_size = STRIPE_SIZE; 1411 bi->bi_next = NULL; 1412 generic_make_request(bi); 1413 } else { 1414 if (rw == 1) 1415 set_bit(STRIPE_DEGRADED, &sh->state); 1416 PRINTK("skip op %ld on disc %d for sector %llu\n", 1417 bi->bi_rw, i, (unsigned long long)sh->sector); 1418 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1419 set_bit(STRIPE_HANDLE, &sh->state); 1420 } 1421 } 1422 } 1423 1424 static inline void raid5_activate_delayed(raid5_conf_t *conf) 1425 { 1426 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { 1427 while (!list_empty(&conf->delayed_list)) { 1428 struct list_head *l = conf->delayed_list.next; 1429 struct stripe_head *sh; 1430 sh = list_entry(l, struct stripe_head, lru); 1431 list_del_init(l); 1432 clear_bit(STRIPE_DELAYED, &sh->state); 1433 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1434 atomic_inc(&conf->preread_active_stripes); 1435 list_add_tail(&sh->lru, &conf->handle_list); 1436 } 1437 } 1438 } 1439 1440 static inline void activate_bit_delay(raid5_conf_t *conf) 1441 { 1442 /* device_lock is held */ 1443 struct list_head head; 1444 list_add(&head, &conf->bitmap_list); 1445 list_del_init(&conf->bitmap_list); 1446 while (!list_empty(&head)) { 1447 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); 1448 list_del_init(&sh->lru); 1449 atomic_inc(&sh->count); 1450 __release_stripe(conf, sh); 1451 } 1452 } 1453 1454 static void unplug_slaves(mddev_t *mddev) 1455 { 1456 raid5_conf_t *conf = mddev_to_conf(mddev); 1457 int i; 1458 1459 rcu_read_lock(); 1460 for (i=0; i<mddev->raid_disks; i++) { 1461 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 1462 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 1463 request_queue_t *r_queue = bdev_get_queue(rdev->bdev); 1464 1465 atomic_inc(&rdev->nr_pending); 1466 rcu_read_unlock(); 1467 1468 if (r_queue->unplug_fn) 1469 r_queue->unplug_fn(r_queue); 1470 1471 rdev_dec_pending(rdev, mddev); 1472 rcu_read_lock(); 1473 } 1474 } 1475 rcu_read_unlock(); 1476 } 1477 1478 static void raid5_unplug_device(request_queue_t *q) 1479 { 1480 mddev_t *mddev = q->queuedata; 1481 raid5_conf_t *conf = mddev_to_conf(mddev); 1482 unsigned long flags; 1483 1484 spin_lock_irqsave(&conf->device_lock, flags); 1485 1486 if (blk_remove_plug(q)) { 1487 conf->seq_flush++; 1488 raid5_activate_delayed(conf); 1489 } 1490 md_wakeup_thread(mddev->thread); 1491 1492 spin_unlock_irqrestore(&conf->device_lock, flags); 1493 1494 unplug_slaves(mddev); 1495 } 1496 1497 static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk, 1498 sector_t *error_sector) 1499 { 1500 mddev_t *mddev = q->queuedata; 1501 raid5_conf_t *conf = mddev_to_conf(mddev); 1502 int i, ret = 0; 1503 1504 rcu_read_lock(); 1505 for (i=0; i<mddev->raid_disks && ret == 0; i++) { 1506 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 1507 if (rdev && !test_bit(Faulty, &rdev->flags)) { 1508 struct block_device *bdev = rdev->bdev; 1509 request_queue_t *r_queue = bdev_get_queue(bdev); 1510 1511 if (!r_queue->issue_flush_fn) 1512 ret = -EOPNOTSUPP; 1513 else { 1514 atomic_inc(&rdev->nr_pending); 1515 rcu_read_unlock(); 1516 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, 1517 error_sector); 1518 rdev_dec_pending(rdev, mddev); 1519 rcu_read_lock(); 1520 } 1521 } 1522 } 1523 rcu_read_unlock(); 1524 return ret; 1525 } 1526 1527 static inline void raid5_plug_device(raid5_conf_t *conf) 1528 { 1529 spin_lock_irq(&conf->device_lock); 1530 blk_plug_device(conf->mddev->queue); 1531 spin_unlock_irq(&conf->device_lock); 1532 } 1533 1534 static int make_request (request_queue_t *q, struct bio * bi) 1535 { 1536 mddev_t *mddev = q->queuedata; 1537 raid5_conf_t *conf = mddev_to_conf(mddev); 1538 const unsigned int raid_disks = conf->raid_disks; 1539 const unsigned int data_disks = raid_disks - 1; 1540 unsigned int dd_idx, pd_idx; 1541 sector_t new_sector; 1542 sector_t logical_sector, last_sector; 1543 struct stripe_head *sh; 1544 const int rw = bio_data_dir(bi); 1545 1546 if (unlikely(bio_barrier(bi))) { 1547 bio_endio(bi, bi->bi_size, -EOPNOTSUPP); 1548 return 0; 1549 } 1550 1551 md_write_start(mddev, bi); 1552 1553 disk_stat_inc(mddev->gendisk, ios[rw]); 1554 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi)); 1555 1556 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 1557 last_sector = bi->bi_sector + (bi->bi_size>>9); 1558 bi->bi_next = NULL; 1559 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ 1560 1561 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { 1562 DEFINE_WAIT(w); 1563 1564 new_sector = raid5_compute_sector(logical_sector, 1565 raid_disks, data_disks, &dd_idx, &pd_idx, conf); 1566 1567 PRINTK("raid5: make_request, sector %llu logical %llu\n", 1568 (unsigned long long)new_sector, 1569 (unsigned long long)logical_sector); 1570 1571 retry: 1572 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); 1573 sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK)); 1574 if (sh) { 1575 if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { 1576 /* Add failed due to overlap. Flush everything 1577 * and wait a while 1578 */ 1579 raid5_unplug_device(mddev->queue); 1580 release_stripe(sh); 1581 schedule(); 1582 goto retry; 1583 } 1584 finish_wait(&conf->wait_for_overlap, &w); 1585 raid5_plug_device(conf); 1586 handle_stripe(sh); 1587 release_stripe(sh); 1588 1589 } else { 1590 /* cannot get stripe for read-ahead, just give-up */ 1591 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1592 finish_wait(&conf->wait_for_overlap, &w); 1593 break; 1594 } 1595 1596 } 1597 spin_lock_irq(&conf->device_lock); 1598 if (--bi->bi_phys_segments == 0) { 1599 int bytes = bi->bi_size; 1600 1601 if ( bio_data_dir(bi) == WRITE ) 1602 md_write_end(mddev); 1603 bi->bi_size = 0; 1604 bi->bi_end_io(bi, bytes, 0); 1605 } 1606 spin_unlock_irq(&conf->device_lock); 1607 return 0; 1608 } 1609 1610 /* FIXME go_faster isn't used */ 1611 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 1612 { 1613 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1614 struct stripe_head *sh; 1615 int sectors_per_chunk = conf->chunk_size >> 9; 1616 sector_t x; 1617 unsigned long stripe; 1618 int chunk_offset; 1619 int dd_idx, pd_idx; 1620 sector_t first_sector; 1621 int raid_disks = conf->raid_disks; 1622 int data_disks = raid_disks-1; 1623 sector_t max_sector = mddev->size << 1; 1624 int sync_blocks; 1625 1626 if (sector_nr >= max_sector) { 1627 /* just being told to finish up .. nothing much to do */ 1628 unplug_slaves(mddev); 1629 1630 if (mddev->curr_resync < max_sector) /* aborted */ 1631 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 1632 &sync_blocks, 1); 1633 else /* compelted sync */ 1634 conf->fullsync = 0; 1635 bitmap_close_sync(mddev->bitmap); 1636 1637 return 0; 1638 } 1639 /* if there is 1 or more failed drives and we are trying 1640 * to resync, then assert that we are finished, because there is 1641 * nothing we can do. 1642 */ 1643 if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 1644 sector_t rv = (mddev->size << 1) - sector_nr; 1645 *skipped = 1; 1646 return rv; 1647 } 1648 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && 1649 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && 1650 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { 1651 /* we can skip this block, and probably more */ 1652 sync_blocks /= STRIPE_SECTORS; 1653 *skipped = 1; 1654 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ 1655 } 1656 1657 x = sector_nr; 1658 chunk_offset = sector_div(x, sectors_per_chunk); 1659 stripe = x; 1660 BUG_ON(x != stripe); 1661 1662 first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk 1663 + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf); 1664 sh = get_active_stripe(conf, sector_nr, pd_idx, 1); 1665 if (sh == NULL) { 1666 sh = get_active_stripe(conf, sector_nr, pd_idx, 0); 1667 /* make sure we don't swamp the stripe cache if someone else 1668 * is trying to get access 1669 */ 1670 schedule_timeout_uninterruptible(1); 1671 } 1672 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0); 1673 spin_lock(&sh->lock); 1674 set_bit(STRIPE_SYNCING, &sh->state); 1675 clear_bit(STRIPE_INSYNC, &sh->state); 1676 spin_unlock(&sh->lock); 1677 1678 handle_stripe(sh); 1679 release_stripe(sh); 1680 1681 return STRIPE_SECTORS; 1682 } 1683 1684 /* 1685 * This is our raid5 kernel thread. 1686 * 1687 * We scan the hash table for stripes which can be handled now. 1688 * During the scan, completed stripes are saved for us by the interrupt 1689 * handler, so that they will not have to wait for our next wakeup. 1690 */ 1691 static void raid5d (mddev_t *mddev) 1692 { 1693 struct stripe_head *sh; 1694 raid5_conf_t *conf = mddev_to_conf(mddev); 1695 int handled; 1696 1697 PRINTK("+++ raid5d active\n"); 1698 1699 md_check_recovery(mddev); 1700 1701 handled = 0; 1702 spin_lock_irq(&conf->device_lock); 1703 while (1) { 1704 struct list_head *first; 1705 1706 if (conf->seq_flush - conf->seq_write > 0) { 1707 int seq = conf->seq_flush; 1708 spin_unlock_irq(&conf->device_lock); 1709 bitmap_unplug(mddev->bitmap); 1710 spin_lock_irq(&conf->device_lock); 1711 conf->seq_write = seq; 1712 activate_bit_delay(conf); 1713 } 1714 1715 if (list_empty(&conf->handle_list) && 1716 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD && 1717 !blk_queue_plugged(mddev->queue) && 1718 !list_empty(&conf->delayed_list)) 1719 raid5_activate_delayed(conf); 1720 1721 if (list_empty(&conf->handle_list)) 1722 break; 1723 1724 first = conf->handle_list.next; 1725 sh = list_entry(first, struct stripe_head, lru); 1726 1727 list_del_init(first); 1728 atomic_inc(&sh->count); 1729 if (atomic_read(&sh->count)!= 1) 1730 BUG(); 1731 spin_unlock_irq(&conf->device_lock); 1732 1733 handled++; 1734 handle_stripe(sh); 1735 release_stripe(sh); 1736 1737 spin_lock_irq(&conf->device_lock); 1738 } 1739 PRINTK("%d stripes handled\n", handled); 1740 1741 spin_unlock_irq(&conf->device_lock); 1742 1743 unplug_slaves(mddev); 1744 1745 PRINTK("--- raid5d inactive\n"); 1746 } 1747 1748 static ssize_t 1749 raid5_show_stripe_cache_size(mddev_t *mddev, char *page) 1750 { 1751 raid5_conf_t *conf = mddev_to_conf(mddev); 1752 if (conf) 1753 return sprintf(page, "%d\n", conf->max_nr_stripes); 1754 else 1755 return 0; 1756 } 1757 1758 static ssize_t 1759 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 1760 { 1761 raid5_conf_t *conf = mddev_to_conf(mddev); 1762 char *end; 1763 int new; 1764 if (len >= PAGE_SIZE) 1765 return -EINVAL; 1766 if (!conf) 1767 return -ENODEV; 1768 1769 new = simple_strtoul(page, &end, 10); 1770 if (!*page || (*end && *end != '\n') ) 1771 return -EINVAL; 1772 if (new <= 16 || new > 32768) 1773 return -EINVAL; 1774 while (new < conf->max_nr_stripes) { 1775 if (drop_one_stripe(conf)) 1776 conf->max_nr_stripes--; 1777 else 1778 break; 1779 } 1780 while (new > conf->max_nr_stripes) { 1781 if (grow_one_stripe(conf)) 1782 conf->max_nr_stripes++; 1783 else break; 1784 } 1785 return len; 1786 } 1787 1788 static struct md_sysfs_entry 1789 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, 1790 raid5_show_stripe_cache_size, 1791 raid5_store_stripe_cache_size); 1792 1793 static ssize_t 1794 stripe_cache_active_show(mddev_t *mddev, char *page) 1795 { 1796 raid5_conf_t *conf = mddev_to_conf(mddev); 1797 if (conf) 1798 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes)); 1799 else 1800 return 0; 1801 } 1802 1803 static struct md_sysfs_entry 1804 raid5_stripecache_active = __ATTR_RO(stripe_cache_active); 1805 1806 static struct attribute *raid5_attrs[] = { 1807 &raid5_stripecache_size.attr, 1808 &raid5_stripecache_active.attr, 1809 NULL, 1810 }; 1811 static struct attribute_group raid5_attrs_group = { 1812 .name = NULL, 1813 .attrs = raid5_attrs, 1814 }; 1815 1816 static int run(mddev_t *mddev) 1817 { 1818 raid5_conf_t *conf; 1819 int raid_disk, memory; 1820 mdk_rdev_t *rdev; 1821 struct disk_info *disk; 1822 struct list_head *tmp; 1823 1824 if (mddev->level != 5 && mddev->level != 4) { 1825 printk("raid5: %s: raid level not set to 4/5 (%d)\n", mdname(mddev), mddev->level); 1826 return -EIO; 1827 } 1828 1829 mddev->private = kmalloc (sizeof (raid5_conf_t) 1830 + mddev->raid_disks * sizeof(struct disk_info), 1831 GFP_KERNEL); 1832 if ((conf = mddev->private) == NULL) 1833 goto abort; 1834 memset (conf, 0, sizeof (*conf) + mddev->raid_disks * sizeof(struct disk_info) ); 1835 conf->mddev = mddev; 1836 1837 if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL) 1838 goto abort; 1839 memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE); 1840 1841 spin_lock_init(&conf->device_lock); 1842 init_waitqueue_head(&conf->wait_for_stripe); 1843 init_waitqueue_head(&conf->wait_for_overlap); 1844 INIT_LIST_HEAD(&conf->handle_list); 1845 INIT_LIST_HEAD(&conf->delayed_list); 1846 INIT_LIST_HEAD(&conf->bitmap_list); 1847 INIT_LIST_HEAD(&conf->inactive_list); 1848 atomic_set(&conf->active_stripes, 0); 1849 atomic_set(&conf->preread_active_stripes, 0); 1850 1851 PRINTK("raid5: run(%s) called.\n", mdname(mddev)); 1852 1853 ITERATE_RDEV(mddev,rdev,tmp) { 1854 raid_disk = rdev->raid_disk; 1855 if (raid_disk >= mddev->raid_disks 1856 || raid_disk < 0) 1857 continue; 1858 disk = conf->disks + raid_disk; 1859 1860 disk->rdev = rdev; 1861 1862 if (test_bit(In_sync, &rdev->flags)) { 1863 char b[BDEVNAME_SIZE]; 1864 printk(KERN_INFO "raid5: device %s operational as raid" 1865 " disk %d\n", bdevname(rdev->bdev,b), 1866 raid_disk); 1867 conf->working_disks++; 1868 } 1869 } 1870 1871 conf->raid_disks = mddev->raid_disks; 1872 /* 1873 * 0 for a fully functional array, 1 for a degraded array. 1874 */ 1875 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks; 1876 conf->mddev = mddev; 1877 conf->chunk_size = mddev->chunk_size; 1878 conf->level = mddev->level; 1879 conf->algorithm = mddev->layout; 1880 conf->max_nr_stripes = NR_STRIPES; 1881 1882 /* device size must be a multiple of chunk size */ 1883 mddev->size &= ~(mddev->chunk_size/1024 -1); 1884 mddev->resync_max_sectors = mddev->size << 1; 1885 1886 if (!conf->chunk_size || conf->chunk_size % 4) { 1887 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", 1888 conf->chunk_size, mdname(mddev)); 1889 goto abort; 1890 } 1891 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) { 1892 printk(KERN_ERR 1893 "raid5: unsupported parity algorithm %d for %s\n", 1894 conf->algorithm, mdname(mddev)); 1895 goto abort; 1896 } 1897 if (mddev->degraded > 1) { 1898 printk(KERN_ERR "raid5: not enough operational devices for %s" 1899 " (%d/%d failed)\n", 1900 mdname(mddev), conf->failed_disks, conf->raid_disks); 1901 goto abort; 1902 } 1903 1904 if (mddev->degraded == 1 && 1905 mddev->recovery_cp != MaxSector) { 1906 printk(KERN_ERR 1907 "raid5: cannot start dirty degraded array for %s\n", 1908 mdname(mddev)); 1909 goto abort; 1910 } 1911 1912 { 1913 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5"); 1914 if (!mddev->thread) { 1915 printk(KERN_ERR 1916 "raid5: couldn't allocate thread for %s\n", 1917 mdname(mddev)); 1918 goto abort; 1919 } 1920 } 1921 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + 1922 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; 1923 if (grow_stripes(conf, conf->max_nr_stripes)) { 1924 printk(KERN_ERR 1925 "raid5: couldn't allocate %dkB for buffers\n", memory); 1926 shrink_stripes(conf); 1927 md_unregister_thread(mddev->thread); 1928 goto abort; 1929 } else 1930 printk(KERN_INFO "raid5: allocated %dkB for %s\n", 1931 memory, mdname(mddev)); 1932 1933 if (mddev->degraded == 0) 1934 printk("raid5: raid level %d set %s active with %d out of %d" 1935 " devices, algorithm %d\n", conf->level, mdname(mddev), 1936 mddev->raid_disks-mddev->degraded, mddev->raid_disks, 1937 conf->algorithm); 1938 else 1939 printk(KERN_ALERT "raid5: raid level %d set %s active with %d" 1940 " out of %d devices, algorithm %d\n", conf->level, 1941 mdname(mddev), mddev->raid_disks - mddev->degraded, 1942 mddev->raid_disks, conf->algorithm); 1943 1944 print_raid5_conf(conf); 1945 1946 /* read-ahead size must cover two whole stripes, which is 1947 * 2 * (n-1) * chunksize where 'n' is the number of raid devices 1948 */ 1949 { 1950 int stripe = (mddev->raid_disks-1) * mddev->chunk_size 1951 / PAGE_CACHE_SIZE; 1952 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 1953 mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 1954 } 1955 1956 /* Ok, everything is just fine now */ 1957 sysfs_create_group(&mddev->kobj, &raid5_attrs_group); 1958 1959 if (mddev->bitmap) 1960 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; 1961 1962 mddev->queue->unplug_fn = raid5_unplug_device; 1963 mddev->queue->issue_flush_fn = raid5_issue_flush; 1964 1965 mddev->array_size = mddev->size * (mddev->raid_disks - 1); 1966 return 0; 1967 abort: 1968 if (conf) { 1969 print_raid5_conf(conf); 1970 if (conf->stripe_hashtbl) 1971 free_pages((unsigned long) conf->stripe_hashtbl, 1972 HASH_PAGES_ORDER); 1973 kfree(conf); 1974 } 1975 mddev->private = NULL; 1976 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); 1977 return -EIO; 1978 } 1979 1980 1981 1982 static int stop(mddev_t *mddev) 1983 { 1984 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1985 1986 md_unregister_thread(mddev->thread); 1987 mddev->thread = NULL; 1988 shrink_stripes(conf); 1989 free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER); 1990 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 1991 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group); 1992 kfree(conf); 1993 mddev->private = NULL; 1994 return 0; 1995 } 1996 1997 #if RAID5_DEBUG 1998 static void print_sh (struct stripe_head *sh) 1999 { 2000 int i; 2001 2002 printk("sh %llu, pd_idx %d, state %ld.\n", 2003 (unsigned long long)sh->sector, sh->pd_idx, sh->state); 2004 printk("sh %llu, count %d.\n", 2005 (unsigned long long)sh->sector, atomic_read(&sh->count)); 2006 printk("sh %llu, ", (unsigned long long)sh->sector); 2007 for (i = 0; i < sh->raid_conf->raid_disks; i++) { 2008 printk("(cache%d: %p %ld) ", 2009 i, sh->dev[i].page, sh->dev[i].flags); 2010 } 2011 printk("\n"); 2012 } 2013 2014 static void printall (raid5_conf_t *conf) 2015 { 2016 struct stripe_head *sh; 2017 int i; 2018 2019 spin_lock_irq(&conf->device_lock); 2020 for (i = 0; i < NR_HASH; i++) { 2021 sh = conf->stripe_hashtbl[i]; 2022 for (; sh; sh = sh->hash_next) { 2023 if (sh->raid_conf != conf) 2024 continue; 2025 print_sh(sh); 2026 } 2027 } 2028 spin_unlock_irq(&conf->device_lock); 2029 } 2030 #endif 2031 2032 static void status (struct seq_file *seq, mddev_t *mddev) 2033 { 2034 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 2035 int i; 2036 2037 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout); 2038 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks); 2039 for (i = 0; i < conf->raid_disks; i++) 2040 seq_printf (seq, "%s", 2041 conf->disks[i].rdev && 2042 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_"); 2043 seq_printf (seq, "]"); 2044 #if RAID5_DEBUG 2045 #define D(x) \ 2046 seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x)) 2047 printall(conf); 2048 #endif 2049 } 2050 2051 static void print_raid5_conf (raid5_conf_t *conf) 2052 { 2053 int i; 2054 struct disk_info *tmp; 2055 2056 printk("RAID5 conf printout:\n"); 2057 if (!conf) { 2058 printk("(conf==NULL)\n"); 2059 return; 2060 } 2061 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks, 2062 conf->working_disks, conf->failed_disks); 2063 2064 for (i = 0; i < conf->raid_disks; i++) { 2065 char b[BDEVNAME_SIZE]; 2066 tmp = conf->disks + i; 2067 if (tmp->rdev) 2068 printk(" disk %d, o:%d, dev:%s\n", 2069 i, !test_bit(Faulty, &tmp->rdev->flags), 2070 bdevname(tmp->rdev->bdev,b)); 2071 } 2072 } 2073 2074 static int raid5_spare_active(mddev_t *mddev) 2075 { 2076 int i; 2077 raid5_conf_t *conf = mddev->private; 2078 struct disk_info *tmp; 2079 2080 for (i = 0; i < conf->raid_disks; i++) { 2081 tmp = conf->disks + i; 2082 if (tmp->rdev 2083 && !test_bit(Faulty, &tmp->rdev->flags) 2084 && !test_bit(In_sync, &tmp->rdev->flags)) { 2085 mddev->degraded--; 2086 conf->failed_disks--; 2087 conf->working_disks++; 2088 set_bit(In_sync, &tmp->rdev->flags); 2089 } 2090 } 2091 print_raid5_conf(conf); 2092 return 0; 2093 } 2094 2095 static int raid5_remove_disk(mddev_t *mddev, int number) 2096 { 2097 raid5_conf_t *conf = mddev->private; 2098 int err = 0; 2099 mdk_rdev_t *rdev; 2100 struct disk_info *p = conf->disks + number; 2101 2102 print_raid5_conf(conf); 2103 rdev = p->rdev; 2104 if (rdev) { 2105 if (test_bit(In_sync, &rdev->flags) || 2106 atomic_read(&rdev->nr_pending)) { 2107 err = -EBUSY; 2108 goto abort; 2109 } 2110 p->rdev = NULL; 2111 synchronize_rcu(); 2112 if (atomic_read(&rdev->nr_pending)) { 2113 /* lost the race, try later */ 2114 err = -EBUSY; 2115 p->rdev = rdev; 2116 } 2117 } 2118 abort: 2119 2120 print_raid5_conf(conf); 2121 return err; 2122 } 2123 2124 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 2125 { 2126 raid5_conf_t *conf = mddev->private; 2127 int found = 0; 2128 int disk; 2129 struct disk_info *p; 2130 2131 if (mddev->degraded > 1) 2132 /* no point adding a device */ 2133 return 0; 2134 2135 /* 2136 * find the disk ... 2137 */ 2138 for (disk=0; disk < mddev->raid_disks; disk++) 2139 if ((p=conf->disks + disk)->rdev == NULL) { 2140 clear_bit(In_sync, &rdev->flags); 2141 rdev->raid_disk = disk; 2142 found = 1; 2143 if (rdev->saved_raid_disk != disk) 2144 conf->fullsync = 1; 2145 rcu_assign_pointer(p->rdev, rdev); 2146 break; 2147 } 2148 print_raid5_conf(conf); 2149 return found; 2150 } 2151 2152 static int raid5_resize(mddev_t *mddev, sector_t sectors) 2153 { 2154 /* no resync is happening, and there is enough space 2155 * on all devices, so we can resize. 2156 * We need to make sure resync covers any new space. 2157 * If the array is shrinking we should possibly wait until 2158 * any io in the removed space completes, but it hardly seems 2159 * worth it. 2160 */ 2161 sectors &= ~((sector_t)mddev->chunk_size/512 - 1); 2162 mddev->array_size = (sectors * (mddev->raid_disks-1))>>1; 2163 set_capacity(mddev->gendisk, mddev->array_size << 1); 2164 mddev->changed = 1; 2165 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) { 2166 mddev->recovery_cp = mddev->size << 1; 2167 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 2168 } 2169 mddev->size = sectors /2; 2170 mddev->resync_max_sectors = sectors; 2171 return 0; 2172 } 2173 2174 static void raid5_quiesce(mddev_t *mddev, int state) 2175 { 2176 raid5_conf_t *conf = mddev_to_conf(mddev); 2177 2178 switch(state) { 2179 case 1: /* stop all writes */ 2180 spin_lock_irq(&conf->device_lock); 2181 conf->quiesce = 1; 2182 wait_event_lock_irq(conf->wait_for_stripe, 2183 atomic_read(&conf->active_stripes) == 0, 2184 conf->device_lock, /* nothing */); 2185 spin_unlock_irq(&conf->device_lock); 2186 break; 2187 2188 case 0: /* re-enable writes */ 2189 spin_lock_irq(&conf->device_lock); 2190 conf->quiesce = 0; 2191 wake_up(&conf->wait_for_stripe); 2192 spin_unlock_irq(&conf->device_lock); 2193 break; 2194 } 2195 if (mddev->thread) { 2196 if (mddev->bitmap) 2197 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; 2198 else 2199 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; 2200 md_wakeup_thread(mddev->thread); 2201 } 2202 } 2203 static mdk_personality_t raid5_personality= 2204 { 2205 .name = "raid5", 2206 .owner = THIS_MODULE, 2207 .make_request = make_request, 2208 .run = run, 2209 .stop = stop, 2210 .status = status, 2211 .error_handler = error, 2212 .hot_add_disk = raid5_add_disk, 2213 .hot_remove_disk= raid5_remove_disk, 2214 .spare_active = raid5_spare_active, 2215 .sync_request = sync_request, 2216 .resize = raid5_resize, 2217 .quiesce = raid5_quiesce, 2218 }; 2219 2220 static int __init raid5_init (void) 2221 { 2222 return register_md_personality (RAID5, &raid5_personality); 2223 } 2224 2225 static void raid5_exit (void) 2226 { 2227 unregister_md_personality (RAID5); 2228 } 2229 2230 module_init(raid5_init); 2231 module_exit(raid5_exit); 2232 MODULE_LICENSE("GPL"); 2233 MODULE_ALIAS("md-personality-4"); /* RAID5 */ 2234