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 * Copyright (C) 2002, 2003 H. Peter Anvin 6 * 7 * RAID-4/5/6 management functions. 8 * Thanks to Penguin Computing for making the RAID-6 development possible 9 * by donating a test server! 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; either version 2, or (at your option) 14 * any later version. 15 * 16 * You should have received a copy of the GNU General Public License 17 * (for example /usr/src/linux/COPYING); if not, write to the Free 18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 /* 22 * BITMAP UNPLUGGING: 23 * 24 * The sequencing for updating the bitmap reliably is a little 25 * subtle (and I got it wrong the first time) so it deserves some 26 * explanation. 27 * 28 * We group bitmap updates into batches. Each batch has a number. 29 * We may write out several batches at once, but that isn't very important. 30 * conf->bm_write is the number of the last batch successfully written. 31 * conf->bm_flush is the number of the last batch that was closed to 32 * new additions. 33 * When we discover that we will need to write to any block in a stripe 34 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq 35 * the number of the batch it will be in. This is bm_flush+1. 36 * When we are ready to do a write, if that batch hasn't been written yet, 37 * we plug the array and queue the stripe for later. 38 * When an unplug happens, we increment bm_flush, thus closing the current 39 * batch. 40 * When we notice that bm_flush > bm_write, we write out all pending updates 41 * to the bitmap, and advance bm_write to where bm_flush was. 42 * This may occasionally write a bit out twice, but is sure never to 43 * miss any bits. 44 */ 45 46 #include <linux/module.h> 47 #include <linux/slab.h> 48 #include <linux/highmem.h> 49 #include <linux/bitops.h> 50 #include <linux/kthread.h> 51 #include <asm/atomic.h> 52 #include "raid6.h" 53 54 #include <linux/raid/bitmap.h> 55 56 /* 57 * Stripe cache 58 */ 59 60 #define NR_STRIPES 256 61 #define STRIPE_SIZE PAGE_SIZE 62 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 63 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 64 #define IO_THRESHOLD 1 65 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) 66 #define HASH_MASK (NR_HASH - 1) 67 68 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])) 69 70 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 71 * order without overlap. There may be several bio's per stripe+device, and 72 * a bio could span several devices. 73 * When walking this list for a particular stripe+device, we must never proceed 74 * beyond a bio that extends past this device, as the next bio might no longer 75 * be valid. 76 * This macro is used to determine the 'next' bio in the list, given the sector 77 * of the current stripe+device 78 */ 79 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL) 80 /* 81 * The following can be used to debug the driver 82 */ 83 #define RAID5_DEBUG 0 84 #define RAID5_PARANOIA 1 85 #if RAID5_PARANOIA && defined(CONFIG_SMP) 86 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock) 87 #else 88 # define CHECK_DEVLOCK() 89 #endif 90 91 #define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x))) 92 #if RAID5_DEBUG 93 #define inline 94 #define __inline__ 95 #endif 96 97 #if !RAID6_USE_EMPTY_ZERO_PAGE 98 /* In .bss so it's zeroed */ 99 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); 100 #endif 101 102 static inline int raid6_next_disk(int disk, int raid_disks) 103 { 104 disk++; 105 return (disk < raid_disks) ? disk : 0; 106 } 107 static void print_raid5_conf (raid5_conf_t *conf); 108 109 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) 110 { 111 if (atomic_dec_and_test(&sh->count)) { 112 BUG_ON(!list_empty(&sh->lru)); 113 BUG_ON(atomic_read(&conf->active_stripes)==0); 114 if (test_bit(STRIPE_HANDLE, &sh->state)) { 115 if (test_bit(STRIPE_DELAYED, &sh->state)) { 116 list_add_tail(&sh->lru, &conf->delayed_list); 117 blk_plug_device(conf->mddev->queue); 118 } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && 119 sh->bm_seq - conf->seq_write > 0) { 120 list_add_tail(&sh->lru, &conf->bitmap_list); 121 blk_plug_device(conf->mddev->queue); 122 } else { 123 clear_bit(STRIPE_BIT_DELAY, &sh->state); 124 list_add_tail(&sh->lru, &conf->handle_list); 125 } 126 md_wakeup_thread(conf->mddev->thread); 127 } else { 128 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 129 atomic_dec(&conf->preread_active_stripes); 130 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 131 md_wakeup_thread(conf->mddev->thread); 132 } 133 atomic_dec(&conf->active_stripes); 134 if (!test_bit(STRIPE_EXPANDING, &sh->state)) { 135 list_add_tail(&sh->lru, &conf->inactive_list); 136 wake_up(&conf->wait_for_stripe); 137 if (conf->retry_read_aligned) 138 md_wakeup_thread(conf->mddev->thread); 139 } 140 } 141 } 142 } 143 static void release_stripe(struct stripe_head *sh) 144 { 145 raid5_conf_t *conf = sh->raid_conf; 146 unsigned long flags; 147 148 spin_lock_irqsave(&conf->device_lock, flags); 149 __release_stripe(conf, sh); 150 spin_unlock_irqrestore(&conf->device_lock, flags); 151 } 152 153 static inline void remove_hash(struct stripe_head *sh) 154 { 155 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector); 156 157 hlist_del_init(&sh->hash); 158 } 159 160 static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) 161 { 162 struct hlist_head *hp = stripe_hash(conf, sh->sector); 163 164 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector); 165 166 CHECK_DEVLOCK(); 167 hlist_add_head(&sh->hash, hp); 168 } 169 170 171 /* find an idle stripe, make sure it is unhashed, and return it. */ 172 static struct stripe_head *get_free_stripe(raid5_conf_t *conf) 173 { 174 struct stripe_head *sh = NULL; 175 struct list_head *first; 176 177 CHECK_DEVLOCK(); 178 if (list_empty(&conf->inactive_list)) 179 goto out; 180 first = conf->inactive_list.next; 181 sh = list_entry(first, struct stripe_head, lru); 182 list_del_init(first); 183 remove_hash(sh); 184 atomic_inc(&conf->active_stripes); 185 out: 186 return sh; 187 } 188 189 static void shrink_buffers(struct stripe_head *sh, int num) 190 { 191 struct page *p; 192 int i; 193 194 for (i=0; i<num ; i++) { 195 p = sh->dev[i].page; 196 if (!p) 197 continue; 198 sh->dev[i].page = NULL; 199 put_page(p); 200 } 201 } 202 203 static int grow_buffers(struct stripe_head *sh, int num) 204 { 205 int i; 206 207 for (i=0; i<num; i++) { 208 struct page *page; 209 210 if (!(page = alloc_page(GFP_KERNEL))) { 211 return 1; 212 } 213 sh->dev[i].page = page; 214 } 215 return 0; 216 } 217 218 static void raid5_build_block (struct stripe_head *sh, int i); 219 220 static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks) 221 { 222 raid5_conf_t *conf = sh->raid_conf; 223 int i; 224 225 BUG_ON(atomic_read(&sh->count) != 0); 226 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); 227 228 CHECK_DEVLOCK(); 229 PRINTK("init_stripe called, stripe %llu\n", 230 (unsigned long long)sh->sector); 231 232 remove_hash(sh); 233 234 sh->sector = sector; 235 sh->pd_idx = pd_idx; 236 sh->state = 0; 237 238 sh->disks = disks; 239 240 for (i = sh->disks; i--; ) { 241 struct r5dev *dev = &sh->dev[i]; 242 243 if (dev->toread || dev->towrite || dev->written || 244 test_bit(R5_LOCKED, &dev->flags)) { 245 printk("sector=%llx i=%d %p %p %p %d\n", 246 (unsigned long long)sh->sector, i, dev->toread, 247 dev->towrite, dev->written, 248 test_bit(R5_LOCKED, &dev->flags)); 249 BUG(); 250 } 251 dev->flags = 0; 252 raid5_build_block(sh, i); 253 } 254 insert_hash(conf, sh); 255 } 256 257 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks) 258 { 259 struct stripe_head *sh; 260 struct hlist_node *hn; 261 262 CHECK_DEVLOCK(); 263 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector); 264 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash) 265 if (sh->sector == sector && sh->disks == disks) 266 return sh; 267 PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector); 268 return NULL; 269 } 270 271 static void unplug_slaves(mddev_t *mddev); 272 static void raid5_unplug_device(request_queue_t *q); 273 274 static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks, 275 int pd_idx, int noblock) 276 { 277 struct stripe_head *sh; 278 279 PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector); 280 281 spin_lock_irq(&conf->device_lock); 282 283 do { 284 wait_event_lock_irq(conf->wait_for_stripe, 285 conf->quiesce == 0, 286 conf->device_lock, /* nothing */); 287 sh = __find_stripe(conf, sector, disks); 288 if (!sh) { 289 if (!conf->inactive_blocked) 290 sh = get_free_stripe(conf); 291 if (noblock && sh == NULL) 292 break; 293 if (!sh) { 294 conf->inactive_blocked = 1; 295 wait_event_lock_irq(conf->wait_for_stripe, 296 !list_empty(&conf->inactive_list) && 297 (atomic_read(&conf->active_stripes) 298 < (conf->max_nr_stripes *3/4) 299 || !conf->inactive_blocked), 300 conf->device_lock, 301 raid5_unplug_device(conf->mddev->queue) 302 ); 303 conf->inactive_blocked = 0; 304 } else 305 init_stripe(sh, sector, pd_idx, disks); 306 } else { 307 if (atomic_read(&sh->count)) { 308 BUG_ON(!list_empty(&sh->lru)); 309 } else { 310 if (!test_bit(STRIPE_HANDLE, &sh->state)) 311 atomic_inc(&conf->active_stripes); 312 if (list_empty(&sh->lru) && 313 !test_bit(STRIPE_EXPANDING, &sh->state)) 314 BUG(); 315 list_del_init(&sh->lru); 316 } 317 } 318 } while (sh == NULL); 319 320 if (sh) 321 atomic_inc(&sh->count); 322 323 spin_unlock_irq(&conf->device_lock); 324 return sh; 325 } 326 327 static int grow_one_stripe(raid5_conf_t *conf) 328 { 329 struct stripe_head *sh; 330 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); 331 if (!sh) 332 return 0; 333 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev)); 334 sh->raid_conf = conf; 335 spin_lock_init(&sh->lock); 336 337 if (grow_buffers(sh, conf->raid_disks)) { 338 shrink_buffers(sh, conf->raid_disks); 339 kmem_cache_free(conf->slab_cache, sh); 340 return 0; 341 } 342 sh->disks = conf->raid_disks; 343 /* we just created an active stripe so... */ 344 atomic_set(&sh->count, 1); 345 atomic_inc(&conf->active_stripes); 346 INIT_LIST_HEAD(&sh->lru); 347 release_stripe(sh); 348 return 1; 349 } 350 351 static int grow_stripes(raid5_conf_t *conf, int num) 352 { 353 struct kmem_cache *sc; 354 int devs = conf->raid_disks; 355 356 sprintf(conf->cache_name[0], "raid5-%s", mdname(conf->mddev)); 357 sprintf(conf->cache_name[1], "raid5-%s-alt", mdname(conf->mddev)); 358 conf->active_name = 0; 359 sc = kmem_cache_create(conf->cache_name[conf->active_name], 360 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 361 0, 0, NULL, NULL); 362 if (!sc) 363 return 1; 364 conf->slab_cache = sc; 365 conf->pool_size = devs; 366 while (num--) 367 if (!grow_one_stripe(conf)) 368 return 1; 369 return 0; 370 } 371 372 #ifdef CONFIG_MD_RAID5_RESHAPE 373 static int resize_stripes(raid5_conf_t *conf, int newsize) 374 { 375 /* Make all the stripes able to hold 'newsize' devices. 376 * New slots in each stripe get 'page' set to a new page. 377 * 378 * This happens in stages: 379 * 1/ create a new kmem_cache and allocate the required number of 380 * stripe_heads. 381 * 2/ gather all the old stripe_heads and tranfer the pages across 382 * to the new stripe_heads. This will have the side effect of 383 * freezing the array as once all stripe_heads have been collected, 384 * no IO will be possible. Old stripe heads are freed once their 385 * pages have been transferred over, and the old kmem_cache is 386 * freed when all stripes are done. 387 * 3/ reallocate conf->disks to be suitable bigger. If this fails, 388 * we simple return a failre status - no need to clean anything up. 389 * 4/ allocate new pages for the new slots in the new stripe_heads. 390 * If this fails, we don't bother trying the shrink the 391 * stripe_heads down again, we just leave them as they are. 392 * As each stripe_head is processed the new one is released into 393 * active service. 394 * 395 * Once step2 is started, we cannot afford to wait for a write, 396 * so we use GFP_NOIO allocations. 397 */ 398 struct stripe_head *osh, *nsh; 399 LIST_HEAD(newstripes); 400 struct disk_info *ndisks; 401 int err = 0; 402 struct kmem_cache *sc; 403 int i; 404 405 if (newsize <= conf->pool_size) 406 return 0; /* never bother to shrink */ 407 408 md_allow_write(conf->mddev); 409 410 /* Step 1 */ 411 sc = kmem_cache_create(conf->cache_name[1-conf->active_name], 412 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev), 413 0, 0, NULL, NULL); 414 if (!sc) 415 return -ENOMEM; 416 417 for (i = conf->max_nr_stripes; i; i--) { 418 nsh = kmem_cache_alloc(sc, GFP_KERNEL); 419 if (!nsh) 420 break; 421 422 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev)); 423 424 nsh->raid_conf = conf; 425 spin_lock_init(&nsh->lock); 426 427 list_add(&nsh->lru, &newstripes); 428 } 429 if (i) { 430 /* didn't get enough, give up */ 431 while (!list_empty(&newstripes)) { 432 nsh = list_entry(newstripes.next, struct stripe_head, lru); 433 list_del(&nsh->lru); 434 kmem_cache_free(sc, nsh); 435 } 436 kmem_cache_destroy(sc); 437 return -ENOMEM; 438 } 439 /* Step 2 - Must use GFP_NOIO now. 440 * OK, we have enough stripes, start collecting inactive 441 * stripes and copying them over 442 */ 443 list_for_each_entry(nsh, &newstripes, lru) { 444 spin_lock_irq(&conf->device_lock); 445 wait_event_lock_irq(conf->wait_for_stripe, 446 !list_empty(&conf->inactive_list), 447 conf->device_lock, 448 unplug_slaves(conf->mddev) 449 ); 450 osh = get_free_stripe(conf); 451 spin_unlock_irq(&conf->device_lock); 452 atomic_set(&nsh->count, 1); 453 for(i=0; i<conf->pool_size; i++) 454 nsh->dev[i].page = osh->dev[i].page; 455 for( ; i<newsize; i++) 456 nsh->dev[i].page = NULL; 457 kmem_cache_free(conf->slab_cache, osh); 458 } 459 kmem_cache_destroy(conf->slab_cache); 460 461 /* Step 3. 462 * At this point, we are holding all the stripes so the array 463 * is completely stalled, so now is a good time to resize 464 * conf->disks. 465 */ 466 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO); 467 if (ndisks) { 468 for (i=0; i<conf->raid_disks; i++) 469 ndisks[i] = conf->disks[i]; 470 kfree(conf->disks); 471 conf->disks = ndisks; 472 } else 473 err = -ENOMEM; 474 475 /* Step 4, return new stripes to service */ 476 while(!list_empty(&newstripes)) { 477 nsh = list_entry(newstripes.next, struct stripe_head, lru); 478 list_del_init(&nsh->lru); 479 for (i=conf->raid_disks; i < newsize; i++) 480 if (nsh->dev[i].page == NULL) { 481 struct page *p = alloc_page(GFP_NOIO); 482 nsh->dev[i].page = p; 483 if (!p) 484 err = -ENOMEM; 485 } 486 release_stripe(nsh); 487 } 488 /* critical section pass, GFP_NOIO no longer needed */ 489 490 conf->slab_cache = sc; 491 conf->active_name = 1-conf->active_name; 492 conf->pool_size = newsize; 493 return err; 494 } 495 #endif 496 497 static int drop_one_stripe(raid5_conf_t *conf) 498 { 499 struct stripe_head *sh; 500 501 spin_lock_irq(&conf->device_lock); 502 sh = get_free_stripe(conf); 503 spin_unlock_irq(&conf->device_lock); 504 if (!sh) 505 return 0; 506 BUG_ON(atomic_read(&sh->count)); 507 shrink_buffers(sh, conf->pool_size); 508 kmem_cache_free(conf->slab_cache, sh); 509 atomic_dec(&conf->active_stripes); 510 return 1; 511 } 512 513 static void shrink_stripes(raid5_conf_t *conf) 514 { 515 while (drop_one_stripe(conf)) 516 ; 517 518 if (conf->slab_cache) 519 kmem_cache_destroy(conf->slab_cache); 520 conf->slab_cache = NULL; 521 } 522 523 static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done, 524 int error) 525 { 526 struct stripe_head *sh = bi->bi_private; 527 raid5_conf_t *conf = sh->raid_conf; 528 int disks = sh->disks, i; 529 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 530 char b[BDEVNAME_SIZE]; 531 mdk_rdev_t *rdev; 532 533 if (bi->bi_size) 534 return 1; 535 536 for (i=0 ; i<disks; i++) 537 if (bi == &sh->dev[i].req) 538 break; 539 540 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n", 541 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 542 uptodate); 543 if (i == disks) { 544 BUG(); 545 return 0; 546 } 547 548 if (uptodate) { 549 set_bit(R5_UPTODATE, &sh->dev[i].flags); 550 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 551 rdev = conf->disks[i].rdev; 552 printk(KERN_INFO "raid5:%s: read error corrected (%lu sectors at %llu on %s)\n", 553 mdname(conf->mddev), STRIPE_SECTORS, 554 (unsigned long long)sh->sector + rdev->data_offset, 555 bdevname(rdev->bdev, b)); 556 clear_bit(R5_ReadError, &sh->dev[i].flags); 557 clear_bit(R5_ReWrite, &sh->dev[i].flags); 558 } 559 if (atomic_read(&conf->disks[i].rdev->read_errors)) 560 atomic_set(&conf->disks[i].rdev->read_errors, 0); 561 } else { 562 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b); 563 int retry = 0; 564 rdev = conf->disks[i].rdev; 565 566 clear_bit(R5_UPTODATE, &sh->dev[i].flags); 567 atomic_inc(&rdev->read_errors); 568 if (conf->mddev->degraded) 569 printk(KERN_WARNING "raid5:%s: read error not correctable (sector %llu on %s).\n", 570 mdname(conf->mddev), 571 (unsigned long long)sh->sector + rdev->data_offset, 572 bdn); 573 else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) 574 /* Oh, no!!! */ 575 printk(KERN_WARNING "raid5:%s: read error NOT corrected!! (sector %llu on %s).\n", 576 mdname(conf->mddev), 577 (unsigned long long)sh->sector + rdev->data_offset, 578 bdn); 579 else if (atomic_read(&rdev->read_errors) 580 > conf->max_nr_stripes) 581 printk(KERN_WARNING 582 "raid5:%s: Too many read errors, failing device %s.\n", 583 mdname(conf->mddev), bdn); 584 else 585 retry = 1; 586 if (retry) 587 set_bit(R5_ReadError, &sh->dev[i].flags); 588 else { 589 clear_bit(R5_ReadError, &sh->dev[i].flags); 590 clear_bit(R5_ReWrite, &sh->dev[i].flags); 591 md_error(conf->mddev, rdev); 592 } 593 } 594 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 595 clear_bit(R5_LOCKED, &sh->dev[i].flags); 596 set_bit(STRIPE_HANDLE, &sh->state); 597 release_stripe(sh); 598 return 0; 599 } 600 601 static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, 602 int error) 603 { 604 struct stripe_head *sh = bi->bi_private; 605 raid5_conf_t *conf = sh->raid_conf; 606 int disks = sh->disks, i; 607 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 608 609 if (bi->bi_size) 610 return 1; 611 612 for (i=0 ; i<disks; i++) 613 if (bi == &sh->dev[i].req) 614 break; 615 616 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n", 617 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 618 uptodate); 619 if (i == disks) { 620 BUG(); 621 return 0; 622 } 623 624 if (!uptodate) 625 md_error(conf->mddev, conf->disks[i].rdev); 626 627 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 628 629 clear_bit(R5_LOCKED, &sh->dev[i].flags); 630 set_bit(STRIPE_HANDLE, &sh->state); 631 release_stripe(sh); 632 return 0; 633 } 634 635 636 static sector_t compute_blocknr(struct stripe_head *sh, int i); 637 638 static void raid5_build_block (struct stripe_head *sh, int i) 639 { 640 struct r5dev *dev = &sh->dev[i]; 641 642 bio_init(&dev->req); 643 dev->req.bi_io_vec = &dev->vec; 644 dev->req.bi_vcnt++; 645 dev->req.bi_max_vecs++; 646 dev->vec.bv_page = dev->page; 647 dev->vec.bv_len = STRIPE_SIZE; 648 dev->vec.bv_offset = 0; 649 650 dev->req.bi_sector = sh->sector; 651 dev->req.bi_private = sh; 652 653 dev->flags = 0; 654 dev->sector = compute_blocknr(sh, i); 655 } 656 657 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 658 { 659 char b[BDEVNAME_SIZE]; 660 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 661 PRINTK("raid5: error called\n"); 662 663 if (!test_bit(Faulty, &rdev->flags)) { 664 set_bit(MD_CHANGE_DEVS, &mddev->flags); 665 if (test_and_clear_bit(In_sync, &rdev->flags)) { 666 unsigned long flags; 667 spin_lock_irqsave(&conf->device_lock, flags); 668 mddev->degraded++; 669 spin_unlock_irqrestore(&conf->device_lock, flags); 670 /* 671 * if recovery was running, make sure it aborts. 672 */ 673 set_bit(MD_RECOVERY_ERR, &mddev->recovery); 674 } 675 set_bit(Faulty, &rdev->flags); 676 printk (KERN_ALERT 677 "raid5: Disk failure on %s, disabling device." 678 " Operation continuing on %d devices\n", 679 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); 680 } 681 } 682 683 /* 684 * Input: a 'big' sector number, 685 * Output: index of the data and parity disk, and the sector # in them. 686 */ 687 static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks, 688 unsigned int data_disks, unsigned int * dd_idx, 689 unsigned int * pd_idx, raid5_conf_t *conf) 690 { 691 long stripe; 692 unsigned long chunk_number; 693 unsigned int chunk_offset; 694 sector_t new_sector; 695 int sectors_per_chunk = conf->chunk_size >> 9; 696 697 /* First compute the information on this sector */ 698 699 /* 700 * Compute the chunk number and the sector offset inside the chunk 701 */ 702 chunk_offset = sector_div(r_sector, sectors_per_chunk); 703 chunk_number = r_sector; 704 BUG_ON(r_sector != chunk_number); 705 706 /* 707 * Compute the stripe number 708 */ 709 stripe = chunk_number / data_disks; 710 711 /* 712 * Compute the data disk and parity disk indexes inside the stripe 713 */ 714 *dd_idx = chunk_number % data_disks; 715 716 /* 717 * Select the parity disk based on the user selected algorithm. 718 */ 719 switch(conf->level) { 720 case 4: 721 *pd_idx = data_disks; 722 break; 723 case 5: 724 switch (conf->algorithm) { 725 case ALGORITHM_LEFT_ASYMMETRIC: 726 *pd_idx = data_disks - stripe % raid_disks; 727 if (*dd_idx >= *pd_idx) 728 (*dd_idx)++; 729 break; 730 case ALGORITHM_RIGHT_ASYMMETRIC: 731 *pd_idx = stripe % raid_disks; 732 if (*dd_idx >= *pd_idx) 733 (*dd_idx)++; 734 break; 735 case ALGORITHM_LEFT_SYMMETRIC: 736 *pd_idx = data_disks - stripe % raid_disks; 737 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 738 break; 739 case ALGORITHM_RIGHT_SYMMETRIC: 740 *pd_idx = stripe % raid_disks; 741 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 742 break; 743 default: 744 printk(KERN_ERR "raid5: unsupported algorithm %d\n", 745 conf->algorithm); 746 } 747 break; 748 case 6: 749 750 /**** FIX THIS ****/ 751 switch (conf->algorithm) { 752 case ALGORITHM_LEFT_ASYMMETRIC: 753 *pd_idx = raid_disks - 1 - (stripe % raid_disks); 754 if (*pd_idx == raid_disks-1) 755 (*dd_idx)++; /* Q D D D P */ 756 else if (*dd_idx >= *pd_idx) 757 (*dd_idx) += 2; /* D D P Q D */ 758 break; 759 case ALGORITHM_RIGHT_ASYMMETRIC: 760 *pd_idx = stripe % raid_disks; 761 if (*pd_idx == raid_disks-1) 762 (*dd_idx)++; /* Q D D D P */ 763 else if (*dd_idx >= *pd_idx) 764 (*dd_idx) += 2; /* D D P Q D */ 765 break; 766 case ALGORITHM_LEFT_SYMMETRIC: 767 *pd_idx = raid_disks - 1 - (stripe % raid_disks); 768 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks; 769 break; 770 case ALGORITHM_RIGHT_SYMMETRIC: 771 *pd_idx = stripe % raid_disks; 772 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks; 773 break; 774 default: 775 printk (KERN_CRIT "raid6: unsupported algorithm %d\n", 776 conf->algorithm); 777 } 778 break; 779 } 780 781 /* 782 * Finally, compute the new sector number 783 */ 784 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; 785 return new_sector; 786 } 787 788 789 static sector_t compute_blocknr(struct stripe_head *sh, int i) 790 { 791 raid5_conf_t *conf = sh->raid_conf; 792 int raid_disks = sh->disks; 793 int data_disks = raid_disks - conf->max_degraded; 794 sector_t new_sector = sh->sector, check; 795 int sectors_per_chunk = conf->chunk_size >> 9; 796 sector_t stripe; 797 int chunk_offset; 798 int chunk_number, dummy1, dummy2, dd_idx = i; 799 sector_t r_sector; 800 801 802 chunk_offset = sector_div(new_sector, sectors_per_chunk); 803 stripe = new_sector; 804 BUG_ON(new_sector != stripe); 805 806 if (i == sh->pd_idx) 807 return 0; 808 switch(conf->level) { 809 case 4: break; 810 case 5: 811 switch (conf->algorithm) { 812 case ALGORITHM_LEFT_ASYMMETRIC: 813 case ALGORITHM_RIGHT_ASYMMETRIC: 814 if (i > sh->pd_idx) 815 i--; 816 break; 817 case ALGORITHM_LEFT_SYMMETRIC: 818 case ALGORITHM_RIGHT_SYMMETRIC: 819 if (i < sh->pd_idx) 820 i += raid_disks; 821 i -= (sh->pd_idx + 1); 822 break; 823 default: 824 printk(KERN_ERR "raid5: unsupported algorithm %d\n", 825 conf->algorithm); 826 } 827 break; 828 case 6: 829 if (i == raid6_next_disk(sh->pd_idx, raid_disks)) 830 return 0; /* It is the Q disk */ 831 switch (conf->algorithm) { 832 case ALGORITHM_LEFT_ASYMMETRIC: 833 case ALGORITHM_RIGHT_ASYMMETRIC: 834 if (sh->pd_idx == raid_disks-1) 835 i--; /* Q D D D P */ 836 else if (i > sh->pd_idx) 837 i -= 2; /* D D P Q D */ 838 break; 839 case ALGORITHM_LEFT_SYMMETRIC: 840 case ALGORITHM_RIGHT_SYMMETRIC: 841 if (sh->pd_idx == raid_disks-1) 842 i--; /* Q D D D P */ 843 else { 844 /* D D P Q D */ 845 if (i < sh->pd_idx) 846 i += raid_disks; 847 i -= (sh->pd_idx + 2); 848 } 849 break; 850 default: 851 printk (KERN_CRIT "raid6: unsupported algorithm %d\n", 852 conf->algorithm); 853 } 854 break; 855 } 856 857 chunk_number = stripe * data_disks + i; 858 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; 859 860 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf); 861 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) { 862 printk(KERN_ERR "compute_blocknr: map not correct\n"); 863 return 0; 864 } 865 return r_sector; 866 } 867 868 869 870 /* 871 * Copy data between a page in the stripe cache, and one or more bion 872 * The page could align with the middle of the bio, or there could be 873 * several bion, each with several bio_vecs, which cover part of the page 874 * Multiple bion are linked together on bi_next. There may be extras 875 * at the end of this list. We ignore them. 876 */ 877 static void copy_data(int frombio, struct bio *bio, 878 struct page *page, 879 sector_t sector) 880 { 881 char *pa = page_address(page); 882 struct bio_vec *bvl; 883 int i; 884 int page_offset; 885 886 if (bio->bi_sector >= sector) 887 page_offset = (signed)(bio->bi_sector - sector) * 512; 888 else 889 page_offset = (signed)(sector - bio->bi_sector) * -512; 890 bio_for_each_segment(bvl, bio, i) { 891 int len = bio_iovec_idx(bio,i)->bv_len; 892 int clen; 893 int b_offset = 0; 894 895 if (page_offset < 0) { 896 b_offset = -page_offset; 897 page_offset += b_offset; 898 len -= b_offset; 899 } 900 901 if (len > 0 && page_offset + len > STRIPE_SIZE) 902 clen = STRIPE_SIZE - page_offset; 903 else clen = len; 904 905 if (clen > 0) { 906 char *ba = __bio_kmap_atomic(bio, i, KM_USER0); 907 if (frombio) 908 memcpy(pa+page_offset, ba+b_offset, clen); 909 else 910 memcpy(ba+b_offset, pa+page_offset, clen); 911 __bio_kunmap_atomic(ba, KM_USER0); 912 } 913 if (clen < len) /* hit end of page */ 914 break; 915 page_offset += len; 916 } 917 } 918 919 #define check_xor() do { \ 920 if (count == MAX_XOR_BLOCKS) { \ 921 xor_block(count, STRIPE_SIZE, ptr); \ 922 count = 1; \ 923 } \ 924 } while(0) 925 926 927 static void compute_block(struct stripe_head *sh, int dd_idx) 928 { 929 int i, count, disks = sh->disks; 930 void *ptr[MAX_XOR_BLOCKS], *p; 931 932 PRINTK("compute_block, stripe %llu, idx %d\n", 933 (unsigned long long)sh->sector, dd_idx); 934 935 ptr[0] = page_address(sh->dev[dd_idx].page); 936 memset(ptr[0], 0, STRIPE_SIZE); 937 count = 1; 938 for (i = disks ; i--; ) { 939 if (i == dd_idx) 940 continue; 941 p = page_address(sh->dev[i].page); 942 if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) 943 ptr[count++] = p; 944 else 945 printk(KERN_ERR "compute_block() %d, stripe %llu, %d" 946 " not present\n", dd_idx, 947 (unsigned long long)sh->sector, i); 948 949 check_xor(); 950 } 951 if (count != 1) 952 xor_block(count, STRIPE_SIZE, ptr); 953 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 954 } 955 956 static void compute_parity5(struct stripe_head *sh, int method) 957 { 958 raid5_conf_t *conf = sh->raid_conf; 959 int i, pd_idx = sh->pd_idx, disks = sh->disks, count; 960 void *ptr[MAX_XOR_BLOCKS]; 961 struct bio *chosen; 962 963 PRINTK("compute_parity5, stripe %llu, method %d\n", 964 (unsigned long long)sh->sector, method); 965 966 count = 1; 967 ptr[0] = page_address(sh->dev[pd_idx].page); 968 switch(method) { 969 case READ_MODIFY_WRITE: 970 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags)); 971 for (i=disks ; i-- ;) { 972 if (i==pd_idx) 973 continue; 974 if (sh->dev[i].towrite && 975 test_bit(R5_UPTODATE, &sh->dev[i].flags)) { 976 ptr[count++] = page_address(sh->dev[i].page); 977 chosen = sh->dev[i].towrite; 978 sh->dev[i].towrite = NULL; 979 980 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 981 wake_up(&conf->wait_for_overlap); 982 983 BUG_ON(sh->dev[i].written); 984 sh->dev[i].written = chosen; 985 check_xor(); 986 } 987 } 988 break; 989 case RECONSTRUCT_WRITE: 990 memset(ptr[0], 0, STRIPE_SIZE); 991 for (i= disks; i-- ;) 992 if (i!=pd_idx && sh->dev[i].towrite) { 993 chosen = sh->dev[i].towrite; 994 sh->dev[i].towrite = NULL; 995 996 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 997 wake_up(&conf->wait_for_overlap); 998 999 BUG_ON(sh->dev[i].written); 1000 sh->dev[i].written = chosen; 1001 } 1002 break; 1003 case CHECK_PARITY: 1004 break; 1005 } 1006 if (count>1) { 1007 xor_block(count, STRIPE_SIZE, ptr); 1008 count = 1; 1009 } 1010 1011 for (i = disks; i--;) 1012 if (sh->dev[i].written) { 1013 sector_t sector = sh->dev[i].sector; 1014 struct bio *wbi = sh->dev[i].written; 1015 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { 1016 copy_data(1, wbi, sh->dev[i].page, sector); 1017 wbi = r5_next_bio(wbi, sector); 1018 } 1019 1020 set_bit(R5_LOCKED, &sh->dev[i].flags); 1021 set_bit(R5_UPTODATE, &sh->dev[i].flags); 1022 } 1023 1024 switch(method) { 1025 case RECONSTRUCT_WRITE: 1026 case CHECK_PARITY: 1027 for (i=disks; i--;) 1028 if (i != pd_idx) { 1029 ptr[count++] = page_address(sh->dev[i].page); 1030 check_xor(); 1031 } 1032 break; 1033 case READ_MODIFY_WRITE: 1034 for (i = disks; i--;) 1035 if (sh->dev[i].written) { 1036 ptr[count++] = page_address(sh->dev[i].page); 1037 check_xor(); 1038 } 1039 } 1040 if (count != 1) 1041 xor_block(count, STRIPE_SIZE, ptr); 1042 1043 if (method != CHECK_PARITY) { 1044 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1045 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 1046 } else 1047 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1048 } 1049 1050 static void compute_parity6(struct stripe_head *sh, int method) 1051 { 1052 raid6_conf_t *conf = sh->raid_conf; 1053 int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = sh->disks, count; 1054 struct bio *chosen; 1055 /**** FIX THIS: This could be very bad if disks is close to 256 ****/ 1056 void *ptrs[disks]; 1057 1058 qd_idx = raid6_next_disk(pd_idx, disks); 1059 d0_idx = raid6_next_disk(qd_idx, disks); 1060 1061 PRINTK("compute_parity, stripe %llu, method %d\n", 1062 (unsigned long long)sh->sector, method); 1063 1064 switch(method) { 1065 case READ_MODIFY_WRITE: 1066 BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */ 1067 case RECONSTRUCT_WRITE: 1068 for (i= disks; i-- ;) 1069 if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) { 1070 chosen = sh->dev[i].towrite; 1071 sh->dev[i].towrite = NULL; 1072 1073 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1074 wake_up(&conf->wait_for_overlap); 1075 1076 BUG_ON(sh->dev[i].written); 1077 sh->dev[i].written = chosen; 1078 } 1079 break; 1080 case CHECK_PARITY: 1081 BUG(); /* Not implemented yet */ 1082 } 1083 1084 for (i = disks; i--;) 1085 if (sh->dev[i].written) { 1086 sector_t sector = sh->dev[i].sector; 1087 struct bio *wbi = sh->dev[i].written; 1088 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { 1089 copy_data(1, wbi, sh->dev[i].page, sector); 1090 wbi = r5_next_bio(wbi, sector); 1091 } 1092 1093 set_bit(R5_LOCKED, &sh->dev[i].flags); 1094 set_bit(R5_UPTODATE, &sh->dev[i].flags); 1095 } 1096 1097 // switch(method) { 1098 // case RECONSTRUCT_WRITE: 1099 // case CHECK_PARITY: 1100 // case UPDATE_PARITY: 1101 /* Note that unlike RAID-5, the ordering of the disks matters greatly. */ 1102 /* FIX: Is this ordering of drives even remotely optimal? */ 1103 count = 0; 1104 i = d0_idx; 1105 do { 1106 ptrs[count++] = page_address(sh->dev[i].page); 1107 if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags)) 1108 printk("block %d/%d not uptodate on parity calc\n", i,count); 1109 i = raid6_next_disk(i, disks); 1110 } while ( i != d0_idx ); 1111 // break; 1112 // } 1113 1114 raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs); 1115 1116 switch(method) { 1117 case RECONSTRUCT_WRITE: 1118 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1119 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags); 1120 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 1121 set_bit(R5_LOCKED, &sh->dev[qd_idx].flags); 1122 break; 1123 case UPDATE_PARITY: 1124 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1125 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags); 1126 break; 1127 } 1128 } 1129 1130 1131 /* Compute one missing block */ 1132 static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero) 1133 { 1134 int i, count, disks = sh->disks; 1135 void *ptr[MAX_XOR_BLOCKS], *p; 1136 int pd_idx = sh->pd_idx; 1137 int qd_idx = raid6_next_disk(pd_idx, disks); 1138 1139 PRINTK("compute_block_1, stripe %llu, idx %d\n", 1140 (unsigned long long)sh->sector, dd_idx); 1141 1142 if ( dd_idx == qd_idx ) { 1143 /* We're actually computing the Q drive */ 1144 compute_parity6(sh, UPDATE_PARITY); 1145 } else { 1146 ptr[0] = page_address(sh->dev[dd_idx].page); 1147 if (!nozero) memset(ptr[0], 0, STRIPE_SIZE); 1148 count = 1; 1149 for (i = disks ; i--; ) { 1150 if (i == dd_idx || i == qd_idx) 1151 continue; 1152 p = page_address(sh->dev[i].page); 1153 if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) 1154 ptr[count++] = p; 1155 else 1156 printk("compute_block() %d, stripe %llu, %d" 1157 " not present\n", dd_idx, 1158 (unsigned long long)sh->sector, i); 1159 1160 check_xor(); 1161 } 1162 if (count != 1) 1163 xor_block(count, STRIPE_SIZE, ptr); 1164 if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 1165 else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 1166 } 1167 } 1168 1169 /* Compute two missing blocks */ 1170 static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2) 1171 { 1172 int i, count, disks = sh->disks; 1173 int pd_idx = sh->pd_idx; 1174 int qd_idx = raid6_next_disk(pd_idx, disks); 1175 int d0_idx = raid6_next_disk(qd_idx, disks); 1176 int faila, failb; 1177 1178 /* faila and failb are disk numbers relative to d0_idx */ 1179 /* pd_idx become disks-2 and qd_idx become disks-1 */ 1180 faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx; 1181 failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx; 1182 1183 BUG_ON(faila == failb); 1184 if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; } 1185 1186 PRINTK("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n", 1187 (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb); 1188 1189 if ( failb == disks-1 ) { 1190 /* Q disk is one of the missing disks */ 1191 if ( faila == disks-2 ) { 1192 /* Missing P+Q, just recompute */ 1193 compute_parity6(sh, UPDATE_PARITY); 1194 return; 1195 } else { 1196 /* We're missing D+Q; recompute D from P */ 1197 compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0); 1198 compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */ 1199 return; 1200 } 1201 } 1202 1203 /* We're missing D+P or D+D; build pointer table */ 1204 { 1205 /**** FIX THIS: This could be very bad if disks is close to 256 ****/ 1206 void *ptrs[disks]; 1207 1208 count = 0; 1209 i = d0_idx; 1210 do { 1211 ptrs[count++] = page_address(sh->dev[i].page); 1212 i = raid6_next_disk(i, disks); 1213 if (i != dd_idx1 && i != dd_idx2 && 1214 !test_bit(R5_UPTODATE, &sh->dev[i].flags)) 1215 printk("compute_2 with missing block %d/%d\n", count, i); 1216 } while ( i != d0_idx ); 1217 1218 if ( failb == disks-2 ) { 1219 /* We're missing D+P. */ 1220 raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs); 1221 } else { 1222 /* We're missing D+D. */ 1223 raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs); 1224 } 1225 1226 /* Both the above update both missing blocks */ 1227 set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags); 1228 set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags); 1229 } 1230 } 1231 1232 1233 1234 /* 1235 * Each stripe/dev can have one or more bion attached. 1236 * toread/towrite point to the first in a chain. 1237 * The bi_next chain must be in order. 1238 */ 1239 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) 1240 { 1241 struct bio **bip; 1242 raid5_conf_t *conf = sh->raid_conf; 1243 int firstwrite=0; 1244 1245 PRINTK("adding bh b#%llu to stripe s#%llu\n", 1246 (unsigned long long)bi->bi_sector, 1247 (unsigned long long)sh->sector); 1248 1249 1250 spin_lock(&sh->lock); 1251 spin_lock_irq(&conf->device_lock); 1252 if (forwrite) { 1253 bip = &sh->dev[dd_idx].towrite; 1254 if (*bip == NULL && sh->dev[dd_idx].written == NULL) 1255 firstwrite = 1; 1256 } else 1257 bip = &sh->dev[dd_idx].toread; 1258 while (*bip && (*bip)->bi_sector < bi->bi_sector) { 1259 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) 1260 goto overlap; 1261 bip = & (*bip)->bi_next; 1262 } 1263 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) 1264 goto overlap; 1265 1266 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next); 1267 if (*bip) 1268 bi->bi_next = *bip; 1269 *bip = bi; 1270 bi->bi_phys_segments ++; 1271 spin_unlock_irq(&conf->device_lock); 1272 spin_unlock(&sh->lock); 1273 1274 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n", 1275 (unsigned long long)bi->bi_sector, 1276 (unsigned long long)sh->sector, dd_idx); 1277 1278 if (conf->mddev->bitmap && firstwrite) { 1279 bitmap_startwrite(conf->mddev->bitmap, sh->sector, 1280 STRIPE_SECTORS, 0); 1281 sh->bm_seq = conf->seq_flush+1; 1282 set_bit(STRIPE_BIT_DELAY, &sh->state); 1283 } 1284 1285 if (forwrite) { 1286 /* check if page is covered */ 1287 sector_t sector = sh->dev[dd_idx].sector; 1288 for (bi=sh->dev[dd_idx].towrite; 1289 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && 1290 bi && bi->bi_sector <= sector; 1291 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { 1292 if (bi->bi_sector + (bi->bi_size>>9) >= sector) 1293 sector = bi->bi_sector + (bi->bi_size>>9); 1294 } 1295 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) 1296 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); 1297 } 1298 return 1; 1299 1300 overlap: 1301 set_bit(R5_Overlap, &sh->dev[dd_idx].flags); 1302 spin_unlock_irq(&conf->device_lock); 1303 spin_unlock(&sh->lock); 1304 return 0; 1305 } 1306 1307 static void end_reshape(raid5_conf_t *conf); 1308 1309 static int page_is_zero(struct page *p) 1310 { 1311 char *a = page_address(p); 1312 return ((*(u32*)a) == 0 && 1313 memcmp(a, a+4, STRIPE_SIZE-4)==0); 1314 } 1315 1316 static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks) 1317 { 1318 int sectors_per_chunk = conf->chunk_size >> 9; 1319 int pd_idx, dd_idx; 1320 int chunk_offset = sector_div(stripe, sectors_per_chunk); 1321 1322 raid5_compute_sector(stripe * (disks - conf->max_degraded) 1323 *sectors_per_chunk + chunk_offset, 1324 disks, disks - conf->max_degraded, 1325 &dd_idx, &pd_idx, conf); 1326 return pd_idx; 1327 } 1328 1329 1330 /* 1331 * handle_stripe - do things to a stripe. 1332 * 1333 * We lock the stripe and then examine the state of various bits 1334 * to see what needs to be done. 1335 * Possible results: 1336 * return some read request which now have data 1337 * return some write requests which are safely on disc 1338 * schedule a read on some buffers 1339 * schedule a write of some buffers 1340 * return confirmation of parity correctness 1341 * 1342 * Parity calculations are done inside the stripe lock 1343 * buffers are taken off read_list or write_list, and bh_cache buffers 1344 * get BH_Lock set before the stripe lock is released. 1345 * 1346 */ 1347 1348 static void handle_stripe5(struct stripe_head *sh) 1349 { 1350 raid5_conf_t *conf = sh->raid_conf; 1351 int disks = sh->disks; 1352 struct bio *return_bi= NULL; 1353 struct bio *bi; 1354 int i; 1355 int syncing, expanding, expanded; 1356 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0; 1357 int non_overwrite = 0; 1358 int failed_num=0; 1359 struct r5dev *dev; 1360 1361 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n", 1362 (unsigned long long)sh->sector, atomic_read(&sh->count), 1363 sh->pd_idx); 1364 1365 spin_lock(&sh->lock); 1366 clear_bit(STRIPE_HANDLE, &sh->state); 1367 clear_bit(STRIPE_DELAYED, &sh->state); 1368 1369 syncing = test_bit(STRIPE_SYNCING, &sh->state); 1370 expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 1371 expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 1372 /* Now to look around and see what can be done */ 1373 1374 rcu_read_lock(); 1375 for (i=disks; i--; ) { 1376 mdk_rdev_t *rdev; 1377 dev = &sh->dev[i]; 1378 clear_bit(R5_Insync, &dev->flags); 1379 1380 PRINTK("check %d: state 0x%lx read %p write %p written %p\n", 1381 i, dev->flags, dev->toread, dev->towrite, dev->written); 1382 /* maybe we can reply to a read */ 1383 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { 1384 struct bio *rbi, *rbi2; 1385 PRINTK("Return read for disc %d\n", i); 1386 spin_lock_irq(&conf->device_lock); 1387 rbi = dev->toread; 1388 dev->toread = NULL; 1389 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 1390 wake_up(&conf->wait_for_overlap); 1391 spin_unlock_irq(&conf->device_lock); 1392 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { 1393 copy_data(0, rbi, dev->page, dev->sector); 1394 rbi2 = r5_next_bio(rbi, dev->sector); 1395 spin_lock_irq(&conf->device_lock); 1396 if (--rbi->bi_phys_segments == 0) { 1397 rbi->bi_next = return_bi; 1398 return_bi = rbi; 1399 } 1400 spin_unlock_irq(&conf->device_lock); 1401 rbi = rbi2; 1402 } 1403 } 1404 1405 /* now count some things */ 1406 if (test_bit(R5_LOCKED, &dev->flags)) locked++; 1407 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++; 1408 1409 1410 if (dev->toread) to_read++; 1411 if (dev->towrite) { 1412 to_write++; 1413 if (!test_bit(R5_OVERWRITE, &dev->flags)) 1414 non_overwrite++; 1415 } 1416 if (dev->written) written++; 1417 rdev = rcu_dereference(conf->disks[i].rdev); 1418 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 1419 /* The ReadError flag will just be confusing now */ 1420 clear_bit(R5_ReadError, &dev->flags); 1421 clear_bit(R5_ReWrite, &dev->flags); 1422 } 1423 if (!rdev || !test_bit(In_sync, &rdev->flags) 1424 || test_bit(R5_ReadError, &dev->flags)) { 1425 failed++; 1426 failed_num = i; 1427 } else 1428 set_bit(R5_Insync, &dev->flags); 1429 } 1430 rcu_read_unlock(); 1431 PRINTK("locked=%d uptodate=%d to_read=%d" 1432 " to_write=%d failed=%d failed_num=%d\n", 1433 locked, uptodate, to_read, to_write, failed, failed_num); 1434 /* check if the array has lost two devices and, if so, some requests might 1435 * need to be failed 1436 */ 1437 if (failed > 1 && to_read+to_write+written) { 1438 for (i=disks; i--; ) { 1439 int bitmap_end = 0; 1440 1441 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1442 mdk_rdev_t *rdev; 1443 rcu_read_lock(); 1444 rdev = rcu_dereference(conf->disks[i].rdev); 1445 if (rdev && test_bit(In_sync, &rdev->flags)) 1446 /* multiple read failures in one stripe */ 1447 md_error(conf->mddev, rdev); 1448 rcu_read_unlock(); 1449 } 1450 1451 spin_lock_irq(&conf->device_lock); 1452 /* fail all writes first */ 1453 bi = sh->dev[i].towrite; 1454 sh->dev[i].towrite = NULL; 1455 if (bi) { to_write--; bitmap_end = 1; } 1456 1457 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1458 wake_up(&conf->wait_for_overlap); 1459 1460 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 1461 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 1462 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1463 if (--bi->bi_phys_segments == 0) { 1464 md_write_end(conf->mddev); 1465 bi->bi_next = return_bi; 1466 return_bi = bi; 1467 } 1468 bi = nextbi; 1469 } 1470 /* and fail all 'written' */ 1471 bi = sh->dev[i].written; 1472 sh->dev[i].written = NULL; 1473 if (bi) bitmap_end = 1; 1474 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { 1475 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 1476 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1477 if (--bi->bi_phys_segments == 0) { 1478 md_write_end(conf->mddev); 1479 bi->bi_next = return_bi; 1480 return_bi = bi; 1481 } 1482 bi = bi2; 1483 } 1484 1485 /* fail any reads if this device is non-operational */ 1486 if (!test_bit(R5_Insync, &sh->dev[i].flags) || 1487 test_bit(R5_ReadError, &sh->dev[i].flags)) { 1488 bi = sh->dev[i].toread; 1489 sh->dev[i].toread = NULL; 1490 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1491 wake_up(&conf->wait_for_overlap); 1492 if (bi) to_read--; 1493 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 1494 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 1495 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1496 if (--bi->bi_phys_segments == 0) { 1497 bi->bi_next = return_bi; 1498 return_bi = bi; 1499 } 1500 bi = nextbi; 1501 } 1502 } 1503 spin_unlock_irq(&conf->device_lock); 1504 if (bitmap_end) 1505 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1506 STRIPE_SECTORS, 0, 0); 1507 } 1508 } 1509 if (failed > 1 && syncing) { 1510 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 1511 clear_bit(STRIPE_SYNCING, &sh->state); 1512 syncing = 0; 1513 } 1514 1515 /* might be able to return some write requests if the parity block 1516 * is safe, or on a failed drive 1517 */ 1518 dev = &sh->dev[sh->pd_idx]; 1519 if ( written && 1520 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) && 1521 test_bit(R5_UPTODATE, &dev->flags)) 1522 || (failed == 1 && failed_num == sh->pd_idx)) 1523 ) { 1524 /* any written block on an uptodate or failed drive can be returned. 1525 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but 1526 * never LOCKED, so we don't need to test 'failed' directly. 1527 */ 1528 for (i=disks; i--; ) 1529 if (sh->dev[i].written) { 1530 dev = &sh->dev[i]; 1531 if (!test_bit(R5_LOCKED, &dev->flags) && 1532 test_bit(R5_UPTODATE, &dev->flags) ) { 1533 /* We can return any write requests */ 1534 struct bio *wbi, *wbi2; 1535 int bitmap_end = 0; 1536 PRINTK("Return write for disc %d\n", i); 1537 spin_lock_irq(&conf->device_lock); 1538 wbi = dev->written; 1539 dev->written = NULL; 1540 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { 1541 wbi2 = r5_next_bio(wbi, dev->sector); 1542 if (--wbi->bi_phys_segments == 0) { 1543 md_write_end(conf->mddev); 1544 wbi->bi_next = return_bi; 1545 return_bi = wbi; 1546 } 1547 wbi = wbi2; 1548 } 1549 if (dev->towrite == NULL) 1550 bitmap_end = 1; 1551 spin_unlock_irq(&conf->device_lock); 1552 if (bitmap_end) 1553 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1554 STRIPE_SECTORS, 1555 !test_bit(STRIPE_DEGRADED, &sh->state), 0); 1556 } 1557 } 1558 } 1559 1560 /* Now we might consider reading some blocks, either to check/generate 1561 * parity, or to satisfy requests 1562 * or to load a block that is being partially written. 1563 */ 1564 if (to_read || non_overwrite || (syncing && (uptodate < disks)) || expanding) { 1565 for (i=disks; i--;) { 1566 dev = &sh->dev[i]; 1567 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1568 (dev->toread || 1569 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 1570 syncing || 1571 expanding || 1572 (failed && (sh->dev[failed_num].toread || 1573 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags)))) 1574 ) 1575 ) { 1576 /* we would like to get this block, possibly 1577 * by computing it, but we might not be able to 1578 */ 1579 if (uptodate == disks-1) { 1580 PRINTK("Computing block %d\n", i); 1581 compute_block(sh, i); 1582 uptodate++; 1583 } else if (test_bit(R5_Insync, &dev->flags)) { 1584 set_bit(R5_LOCKED, &dev->flags); 1585 set_bit(R5_Wantread, &dev->flags); 1586 locked++; 1587 PRINTK("Reading block %d (sync=%d)\n", 1588 i, syncing); 1589 } 1590 } 1591 } 1592 set_bit(STRIPE_HANDLE, &sh->state); 1593 } 1594 1595 /* now to consider writing and what else, if anything should be read */ 1596 if (to_write) { 1597 int rmw=0, rcw=0; 1598 for (i=disks ; i--;) { 1599 /* would I have to read this buffer for read_modify_write */ 1600 dev = &sh->dev[i]; 1601 if ((dev->towrite || i == sh->pd_idx) && 1602 (!test_bit(R5_LOCKED, &dev->flags) 1603 ) && 1604 !test_bit(R5_UPTODATE, &dev->flags)) { 1605 if (test_bit(R5_Insync, &dev->flags) 1606 /* && !(!mddev->insync && i == sh->pd_idx) */ 1607 ) 1608 rmw++; 1609 else rmw += 2*disks; /* cannot read it */ 1610 } 1611 /* Would I have to read this buffer for reconstruct_write */ 1612 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 1613 (!test_bit(R5_LOCKED, &dev->flags) 1614 ) && 1615 !test_bit(R5_UPTODATE, &dev->flags)) { 1616 if (test_bit(R5_Insync, &dev->flags)) rcw++; 1617 else rcw += 2*disks; 1618 } 1619 } 1620 PRINTK("for sector %llu, rmw=%d rcw=%d\n", 1621 (unsigned long long)sh->sector, rmw, rcw); 1622 set_bit(STRIPE_HANDLE, &sh->state); 1623 if (rmw < rcw && rmw > 0) 1624 /* prefer read-modify-write, but need to get some data */ 1625 for (i=disks; i--;) { 1626 dev = &sh->dev[i]; 1627 if ((dev->towrite || i == sh->pd_idx) && 1628 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1629 test_bit(R5_Insync, &dev->flags)) { 1630 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1631 { 1632 PRINTK("Read_old block %d for r-m-w\n", i); 1633 set_bit(R5_LOCKED, &dev->flags); 1634 set_bit(R5_Wantread, &dev->flags); 1635 locked++; 1636 } else { 1637 set_bit(STRIPE_DELAYED, &sh->state); 1638 set_bit(STRIPE_HANDLE, &sh->state); 1639 } 1640 } 1641 } 1642 if (rcw <= rmw && rcw > 0) 1643 /* want reconstruct write, but need to get some data */ 1644 for (i=disks; i--;) { 1645 dev = &sh->dev[i]; 1646 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 1647 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 1648 test_bit(R5_Insync, &dev->flags)) { 1649 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 1650 { 1651 PRINTK("Read_old block %d for Reconstruct\n", i); 1652 set_bit(R5_LOCKED, &dev->flags); 1653 set_bit(R5_Wantread, &dev->flags); 1654 locked++; 1655 } else { 1656 set_bit(STRIPE_DELAYED, &sh->state); 1657 set_bit(STRIPE_HANDLE, &sh->state); 1658 } 1659 } 1660 } 1661 /* now if nothing is locked, and if we have enough data, we can start a write request */ 1662 if (locked == 0 && (rcw == 0 ||rmw == 0) && 1663 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 1664 PRINTK("Computing parity...\n"); 1665 compute_parity5(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE); 1666 /* now every locked buffer is ready to be written */ 1667 for (i=disks; i--;) 1668 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { 1669 PRINTK("Writing block %d\n", i); 1670 locked++; 1671 set_bit(R5_Wantwrite, &sh->dev[i].flags); 1672 if (!test_bit(R5_Insync, &sh->dev[i].flags) 1673 || (i==sh->pd_idx && failed == 0)) 1674 set_bit(STRIPE_INSYNC, &sh->state); 1675 } 1676 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 1677 atomic_dec(&conf->preread_active_stripes); 1678 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 1679 md_wakeup_thread(conf->mddev->thread); 1680 } 1681 } 1682 } 1683 1684 /* maybe we need to check and possibly fix the parity for this stripe 1685 * Any reads will already have been scheduled, so we just see if enough data 1686 * is available 1687 */ 1688 if (syncing && locked == 0 && 1689 !test_bit(STRIPE_INSYNC, &sh->state)) { 1690 set_bit(STRIPE_HANDLE, &sh->state); 1691 if (failed == 0) { 1692 BUG_ON(uptodate != disks); 1693 compute_parity5(sh, CHECK_PARITY); 1694 uptodate--; 1695 if (page_is_zero(sh->dev[sh->pd_idx].page)) { 1696 /* parity is correct (on disc, not in buffer any more) */ 1697 set_bit(STRIPE_INSYNC, &sh->state); 1698 } else { 1699 conf->mddev->resync_mismatches += STRIPE_SECTORS; 1700 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 1701 /* don't try to repair!! */ 1702 set_bit(STRIPE_INSYNC, &sh->state); 1703 else { 1704 compute_block(sh, sh->pd_idx); 1705 uptodate++; 1706 } 1707 } 1708 } 1709 if (!test_bit(STRIPE_INSYNC, &sh->state)) { 1710 /* either failed parity check, or recovery is happening */ 1711 if (failed==0) 1712 failed_num = sh->pd_idx; 1713 dev = &sh->dev[failed_num]; 1714 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); 1715 BUG_ON(uptodate != disks); 1716 1717 set_bit(R5_LOCKED, &dev->flags); 1718 set_bit(R5_Wantwrite, &dev->flags); 1719 clear_bit(STRIPE_DEGRADED, &sh->state); 1720 locked++; 1721 set_bit(STRIPE_INSYNC, &sh->state); 1722 } 1723 } 1724 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 1725 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 1726 clear_bit(STRIPE_SYNCING, &sh->state); 1727 } 1728 1729 /* If the failed drive is just a ReadError, then we might need to progress 1730 * the repair/check process 1731 */ 1732 if (failed == 1 && ! conf->mddev->ro && 1733 test_bit(R5_ReadError, &sh->dev[failed_num].flags) 1734 && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags) 1735 && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags) 1736 ) { 1737 dev = &sh->dev[failed_num]; 1738 if (!test_bit(R5_ReWrite, &dev->flags)) { 1739 set_bit(R5_Wantwrite, &dev->flags); 1740 set_bit(R5_ReWrite, &dev->flags); 1741 set_bit(R5_LOCKED, &dev->flags); 1742 locked++; 1743 } else { 1744 /* let's read it back */ 1745 set_bit(R5_Wantread, &dev->flags); 1746 set_bit(R5_LOCKED, &dev->flags); 1747 locked++; 1748 } 1749 } 1750 1751 if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) { 1752 /* Need to write out all blocks after computing parity */ 1753 sh->disks = conf->raid_disks; 1754 sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks); 1755 compute_parity5(sh, RECONSTRUCT_WRITE); 1756 for (i= conf->raid_disks; i--;) { 1757 set_bit(R5_LOCKED, &sh->dev[i].flags); 1758 locked++; 1759 set_bit(R5_Wantwrite, &sh->dev[i].flags); 1760 } 1761 clear_bit(STRIPE_EXPANDING, &sh->state); 1762 } else if (expanded) { 1763 clear_bit(STRIPE_EXPAND_READY, &sh->state); 1764 atomic_dec(&conf->reshape_stripes); 1765 wake_up(&conf->wait_for_overlap); 1766 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 1767 } 1768 1769 if (expanding && locked == 0) { 1770 /* We have read all the blocks in this stripe and now we need to 1771 * copy some of them into a target stripe for expand. 1772 */ 1773 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state); 1774 for (i=0; i< sh->disks; i++) 1775 if (i != sh->pd_idx) { 1776 int dd_idx, pd_idx, j; 1777 struct stripe_head *sh2; 1778 1779 sector_t bn = compute_blocknr(sh, i); 1780 sector_t s = raid5_compute_sector(bn, conf->raid_disks, 1781 conf->raid_disks-1, 1782 &dd_idx, &pd_idx, conf); 1783 sh2 = get_active_stripe(conf, s, conf->raid_disks, pd_idx, 1); 1784 if (sh2 == NULL) 1785 /* so far only the early blocks of this stripe 1786 * have been requested. When later blocks 1787 * get requested, we will try again 1788 */ 1789 continue; 1790 if(!test_bit(STRIPE_EXPANDING, &sh2->state) || 1791 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) { 1792 /* must have already done this block */ 1793 release_stripe(sh2); 1794 continue; 1795 } 1796 memcpy(page_address(sh2->dev[dd_idx].page), 1797 page_address(sh->dev[i].page), 1798 STRIPE_SIZE); 1799 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags); 1800 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags); 1801 for (j=0; j<conf->raid_disks; j++) 1802 if (j != sh2->pd_idx && 1803 !test_bit(R5_Expanded, &sh2->dev[j].flags)) 1804 break; 1805 if (j == conf->raid_disks) { 1806 set_bit(STRIPE_EXPAND_READY, &sh2->state); 1807 set_bit(STRIPE_HANDLE, &sh2->state); 1808 } 1809 release_stripe(sh2); 1810 } 1811 } 1812 1813 spin_unlock(&sh->lock); 1814 1815 while ((bi=return_bi)) { 1816 int bytes = bi->bi_size; 1817 1818 return_bi = bi->bi_next; 1819 bi->bi_next = NULL; 1820 bi->bi_size = 0; 1821 bi->bi_end_io(bi, bytes, 1822 test_bit(BIO_UPTODATE, &bi->bi_flags) 1823 ? 0 : -EIO); 1824 } 1825 for (i=disks; i-- ;) { 1826 int rw; 1827 struct bio *bi; 1828 mdk_rdev_t *rdev; 1829 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 1830 rw = WRITE; 1831 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 1832 rw = READ; 1833 else 1834 continue; 1835 1836 bi = &sh->dev[i].req; 1837 1838 bi->bi_rw = rw; 1839 if (rw == WRITE) 1840 bi->bi_end_io = raid5_end_write_request; 1841 else 1842 bi->bi_end_io = raid5_end_read_request; 1843 1844 rcu_read_lock(); 1845 rdev = rcu_dereference(conf->disks[i].rdev); 1846 if (rdev && test_bit(Faulty, &rdev->flags)) 1847 rdev = NULL; 1848 if (rdev) 1849 atomic_inc(&rdev->nr_pending); 1850 rcu_read_unlock(); 1851 1852 if (rdev) { 1853 if (syncing || expanding || expanded) 1854 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 1855 1856 bi->bi_bdev = rdev->bdev; 1857 PRINTK("for %llu schedule op %ld on disc %d\n", 1858 (unsigned long long)sh->sector, bi->bi_rw, i); 1859 atomic_inc(&sh->count); 1860 bi->bi_sector = sh->sector + rdev->data_offset; 1861 bi->bi_flags = 1 << BIO_UPTODATE; 1862 bi->bi_vcnt = 1; 1863 bi->bi_max_vecs = 1; 1864 bi->bi_idx = 0; 1865 bi->bi_io_vec = &sh->dev[i].vec; 1866 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 1867 bi->bi_io_vec[0].bv_offset = 0; 1868 bi->bi_size = STRIPE_SIZE; 1869 bi->bi_next = NULL; 1870 if (rw == WRITE && 1871 test_bit(R5_ReWrite, &sh->dev[i].flags)) 1872 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors); 1873 generic_make_request(bi); 1874 } else { 1875 if (rw == WRITE) 1876 set_bit(STRIPE_DEGRADED, &sh->state); 1877 PRINTK("skip op %ld on disc %d for sector %llu\n", 1878 bi->bi_rw, i, (unsigned long long)sh->sector); 1879 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1880 set_bit(STRIPE_HANDLE, &sh->state); 1881 } 1882 } 1883 } 1884 1885 static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page) 1886 { 1887 raid6_conf_t *conf = sh->raid_conf; 1888 int disks = sh->disks; 1889 struct bio *return_bi= NULL; 1890 struct bio *bi; 1891 int i; 1892 int syncing, expanding, expanded; 1893 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0; 1894 int non_overwrite = 0; 1895 int failed_num[2] = {0, 0}; 1896 struct r5dev *dev, *pdev, *qdev; 1897 int pd_idx = sh->pd_idx; 1898 int qd_idx = raid6_next_disk(pd_idx, disks); 1899 int p_failed, q_failed; 1900 1901 PRINTK("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d, qd_idx=%d\n", 1902 (unsigned long long)sh->sector, sh->state, atomic_read(&sh->count), 1903 pd_idx, qd_idx); 1904 1905 spin_lock(&sh->lock); 1906 clear_bit(STRIPE_HANDLE, &sh->state); 1907 clear_bit(STRIPE_DELAYED, &sh->state); 1908 1909 syncing = test_bit(STRIPE_SYNCING, &sh->state); 1910 expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 1911 expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 1912 /* Now to look around and see what can be done */ 1913 1914 rcu_read_lock(); 1915 for (i=disks; i--; ) { 1916 mdk_rdev_t *rdev; 1917 dev = &sh->dev[i]; 1918 clear_bit(R5_Insync, &dev->flags); 1919 1920 PRINTK("check %d: state 0x%lx read %p write %p written %p\n", 1921 i, dev->flags, dev->toread, dev->towrite, dev->written); 1922 /* maybe we can reply to a read */ 1923 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { 1924 struct bio *rbi, *rbi2; 1925 PRINTK("Return read for disc %d\n", i); 1926 spin_lock_irq(&conf->device_lock); 1927 rbi = dev->toread; 1928 dev->toread = NULL; 1929 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 1930 wake_up(&conf->wait_for_overlap); 1931 spin_unlock_irq(&conf->device_lock); 1932 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { 1933 copy_data(0, rbi, dev->page, dev->sector); 1934 rbi2 = r5_next_bio(rbi, dev->sector); 1935 spin_lock_irq(&conf->device_lock); 1936 if (--rbi->bi_phys_segments == 0) { 1937 rbi->bi_next = return_bi; 1938 return_bi = rbi; 1939 } 1940 spin_unlock_irq(&conf->device_lock); 1941 rbi = rbi2; 1942 } 1943 } 1944 1945 /* now count some things */ 1946 if (test_bit(R5_LOCKED, &dev->flags)) locked++; 1947 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++; 1948 1949 1950 if (dev->toread) to_read++; 1951 if (dev->towrite) { 1952 to_write++; 1953 if (!test_bit(R5_OVERWRITE, &dev->flags)) 1954 non_overwrite++; 1955 } 1956 if (dev->written) written++; 1957 rdev = rcu_dereference(conf->disks[i].rdev); 1958 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 1959 /* The ReadError flag will just be confusing now */ 1960 clear_bit(R5_ReadError, &dev->flags); 1961 clear_bit(R5_ReWrite, &dev->flags); 1962 } 1963 if (!rdev || !test_bit(In_sync, &rdev->flags) 1964 || test_bit(R5_ReadError, &dev->flags)) { 1965 if ( failed < 2 ) 1966 failed_num[failed] = i; 1967 failed++; 1968 } else 1969 set_bit(R5_Insync, &dev->flags); 1970 } 1971 rcu_read_unlock(); 1972 PRINTK("locked=%d uptodate=%d to_read=%d" 1973 " to_write=%d failed=%d failed_num=%d,%d\n", 1974 locked, uptodate, to_read, to_write, failed, 1975 failed_num[0], failed_num[1]); 1976 /* check if the array has lost >2 devices and, if so, some requests might 1977 * need to be failed 1978 */ 1979 if (failed > 2 && to_read+to_write+written) { 1980 for (i=disks; i--; ) { 1981 int bitmap_end = 0; 1982 1983 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1984 mdk_rdev_t *rdev; 1985 rcu_read_lock(); 1986 rdev = rcu_dereference(conf->disks[i].rdev); 1987 if (rdev && test_bit(In_sync, &rdev->flags)) 1988 /* multiple read failures in one stripe */ 1989 md_error(conf->mddev, rdev); 1990 rcu_read_unlock(); 1991 } 1992 1993 spin_lock_irq(&conf->device_lock); 1994 /* fail all writes first */ 1995 bi = sh->dev[i].towrite; 1996 sh->dev[i].towrite = NULL; 1997 if (bi) { to_write--; bitmap_end = 1; } 1998 1999 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 2000 wake_up(&conf->wait_for_overlap); 2001 2002 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 2003 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 2004 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2005 if (--bi->bi_phys_segments == 0) { 2006 md_write_end(conf->mddev); 2007 bi->bi_next = return_bi; 2008 return_bi = bi; 2009 } 2010 bi = nextbi; 2011 } 2012 /* and fail all 'written' */ 2013 bi = sh->dev[i].written; 2014 sh->dev[i].written = NULL; 2015 if (bi) bitmap_end = 1; 2016 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { 2017 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 2018 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2019 if (--bi->bi_phys_segments == 0) { 2020 md_write_end(conf->mddev); 2021 bi->bi_next = return_bi; 2022 return_bi = bi; 2023 } 2024 bi = bi2; 2025 } 2026 2027 /* fail any reads if this device is non-operational */ 2028 if (!test_bit(R5_Insync, &sh->dev[i].flags) || 2029 test_bit(R5_ReadError, &sh->dev[i].flags)) { 2030 bi = sh->dev[i].toread; 2031 sh->dev[i].toread = NULL; 2032 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 2033 wake_up(&conf->wait_for_overlap); 2034 if (bi) to_read--; 2035 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ 2036 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 2037 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2038 if (--bi->bi_phys_segments == 0) { 2039 bi->bi_next = return_bi; 2040 return_bi = bi; 2041 } 2042 bi = nextbi; 2043 } 2044 } 2045 spin_unlock_irq(&conf->device_lock); 2046 if (bitmap_end) 2047 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 2048 STRIPE_SECTORS, 0, 0); 2049 } 2050 } 2051 if (failed > 2 && syncing) { 2052 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 2053 clear_bit(STRIPE_SYNCING, &sh->state); 2054 syncing = 0; 2055 } 2056 2057 /* 2058 * might be able to return some write requests if the parity blocks 2059 * are safe, or on a failed drive 2060 */ 2061 pdev = &sh->dev[pd_idx]; 2062 p_failed = (failed >= 1 && failed_num[0] == pd_idx) 2063 || (failed >= 2 && failed_num[1] == pd_idx); 2064 qdev = &sh->dev[qd_idx]; 2065 q_failed = (failed >= 1 && failed_num[0] == qd_idx) 2066 || (failed >= 2 && failed_num[1] == qd_idx); 2067 2068 if ( written && 2069 ( p_failed || ((test_bit(R5_Insync, &pdev->flags) 2070 && !test_bit(R5_LOCKED, &pdev->flags) 2071 && test_bit(R5_UPTODATE, &pdev->flags))) ) && 2072 ( q_failed || ((test_bit(R5_Insync, &qdev->flags) 2073 && !test_bit(R5_LOCKED, &qdev->flags) 2074 && test_bit(R5_UPTODATE, &qdev->flags))) ) ) { 2075 /* any written block on an uptodate or failed drive can be 2076 * returned. Note that if we 'wrote' to a failed drive, 2077 * it will be UPTODATE, but never LOCKED, so we don't need 2078 * to test 'failed' directly. 2079 */ 2080 for (i=disks; i--; ) 2081 if (sh->dev[i].written) { 2082 dev = &sh->dev[i]; 2083 if (!test_bit(R5_LOCKED, &dev->flags) && 2084 test_bit(R5_UPTODATE, &dev->flags) ) { 2085 /* We can return any write requests */ 2086 int bitmap_end = 0; 2087 struct bio *wbi, *wbi2; 2088 PRINTK("Return write for stripe %llu disc %d\n", 2089 (unsigned long long)sh->sector, i); 2090 spin_lock_irq(&conf->device_lock); 2091 wbi = dev->written; 2092 dev->written = NULL; 2093 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { 2094 wbi2 = r5_next_bio(wbi, dev->sector); 2095 if (--wbi->bi_phys_segments == 0) { 2096 md_write_end(conf->mddev); 2097 wbi->bi_next = return_bi; 2098 return_bi = wbi; 2099 } 2100 wbi = wbi2; 2101 } 2102 if (dev->towrite == NULL) 2103 bitmap_end = 1; 2104 spin_unlock_irq(&conf->device_lock); 2105 if (bitmap_end) 2106 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 2107 STRIPE_SECTORS, 2108 !test_bit(STRIPE_DEGRADED, &sh->state), 0); 2109 } 2110 } 2111 } 2112 2113 /* Now we might consider reading some blocks, either to check/generate 2114 * parity, or to satisfy requests 2115 * or to load a block that is being partially written. 2116 */ 2117 if (to_read || non_overwrite || (to_write && failed) || 2118 (syncing && (uptodate < disks)) || expanding) { 2119 for (i=disks; i--;) { 2120 dev = &sh->dev[i]; 2121 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 2122 (dev->toread || 2123 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 2124 syncing || 2125 expanding || 2126 (failed >= 1 && (sh->dev[failed_num[0]].toread || to_write)) || 2127 (failed >= 2 && (sh->dev[failed_num[1]].toread || to_write)) 2128 ) 2129 ) { 2130 /* we would like to get this block, possibly 2131 * by computing it, but we might not be able to 2132 */ 2133 if (uptodate == disks-1) { 2134 PRINTK("Computing stripe %llu block %d\n", 2135 (unsigned long long)sh->sector, i); 2136 compute_block_1(sh, i, 0); 2137 uptodate++; 2138 } else if ( uptodate == disks-2 && failed >= 2 ) { 2139 /* Computing 2-failure is *very* expensive; only do it if failed >= 2 */ 2140 int other; 2141 for (other=disks; other--;) { 2142 if ( other == i ) 2143 continue; 2144 if ( !test_bit(R5_UPTODATE, &sh->dev[other].flags) ) 2145 break; 2146 } 2147 BUG_ON(other < 0); 2148 PRINTK("Computing stripe %llu blocks %d,%d\n", 2149 (unsigned long long)sh->sector, i, other); 2150 compute_block_2(sh, i, other); 2151 uptodate += 2; 2152 } else if (test_bit(R5_Insync, &dev->flags)) { 2153 set_bit(R5_LOCKED, &dev->flags); 2154 set_bit(R5_Wantread, &dev->flags); 2155 locked++; 2156 PRINTK("Reading block %d (sync=%d)\n", 2157 i, syncing); 2158 } 2159 } 2160 } 2161 set_bit(STRIPE_HANDLE, &sh->state); 2162 } 2163 2164 /* now to consider writing and what else, if anything should be read */ 2165 if (to_write) { 2166 int rcw=0, must_compute=0; 2167 for (i=disks ; i--;) { 2168 dev = &sh->dev[i]; 2169 /* Would I have to read this buffer for reconstruct_write */ 2170 if (!test_bit(R5_OVERWRITE, &dev->flags) 2171 && i != pd_idx && i != qd_idx 2172 && (!test_bit(R5_LOCKED, &dev->flags) 2173 ) && 2174 !test_bit(R5_UPTODATE, &dev->flags)) { 2175 if (test_bit(R5_Insync, &dev->flags)) rcw++; 2176 else { 2177 PRINTK("raid6: must_compute: disk %d flags=%#lx\n", i, dev->flags); 2178 must_compute++; 2179 } 2180 } 2181 } 2182 PRINTK("for sector %llu, rcw=%d, must_compute=%d\n", 2183 (unsigned long long)sh->sector, rcw, must_compute); 2184 set_bit(STRIPE_HANDLE, &sh->state); 2185 2186 if (rcw > 0) 2187 /* want reconstruct write, but need to get some data */ 2188 for (i=disks; i--;) { 2189 dev = &sh->dev[i]; 2190 if (!test_bit(R5_OVERWRITE, &dev->flags) 2191 && !(failed == 0 && (i == pd_idx || i == qd_idx)) 2192 && !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && 2193 test_bit(R5_Insync, &dev->flags)) { 2194 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 2195 { 2196 PRINTK("Read_old stripe %llu block %d for Reconstruct\n", 2197 (unsigned long long)sh->sector, i); 2198 set_bit(R5_LOCKED, &dev->flags); 2199 set_bit(R5_Wantread, &dev->flags); 2200 locked++; 2201 } else { 2202 PRINTK("Request delayed stripe %llu block %d for Reconstruct\n", 2203 (unsigned long long)sh->sector, i); 2204 set_bit(STRIPE_DELAYED, &sh->state); 2205 set_bit(STRIPE_HANDLE, &sh->state); 2206 } 2207 } 2208 } 2209 /* now if nothing is locked, and if we have enough data, we can start a write request */ 2210 if (locked == 0 && rcw == 0 && 2211 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 2212 if ( must_compute > 0 ) { 2213 /* We have failed blocks and need to compute them */ 2214 switch ( failed ) { 2215 case 0: BUG(); 2216 case 1: compute_block_1(sh, failed_num[0], 0); break; 2217 case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break; 2218 default: BUG(); /* This request should have been failed? */ 2219 } 2220 } 2221 2222 PRINTK("Computing parity for stripe %llu\n", (unsigned long long)sh->sector); 2223 compute_parity6(sh, RECONSTRUCT_WRITE); 2224 /* now every locked buffer is ready to be written */ 2225 for (i=disks; i--;) 2226 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { 2227 PRINTK("Writing stripe %llu block %d\n", 2228 (unsigned long long)sh->sector, i); 2229 locked++; 2230 set_bit(R5_Wantwrite, &sh->dev[i].flags); 2231 } 2232 /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */ 2233 set_bit(STRIPE_INSYNC, &sh->state); 2234 2235 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2236 atomic_dec(&conf->preread_active_stripes); 2237 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 2238 md_wakeup_thread(conf->mddev->thread); 2239 } 2240 } 2241 } 2242 2243 /* maybe we need to check and possibly fix the parity for this stripe 2244 * Any reads will already have been scheduled, so we just see if enough data 2245 * is available 2246 */ 2247 if (syncing && locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state)) { 2248 int update_p = 0, update_q = 0; 2249 struct r5dev *dev; 2250 2251 set_bit(STRIPE_HANDLE, &sh->state); 2252 2253 BUG_ON(failed>2); 2254 BUG_ON(uptodate < disks); 2255 /* Want to check and possibly repair P and Q. 2256 * However there could be one 'failed' device, in which 2257 * case we can only check one of them, possibly using the 2258 * other to generate missing data 2259 */ 2260 2261 /* If !tmp_page, we cannot do the calculations, 2262 * but as we have set STRIPE_HANDLE, we will soon be called 2263 * by stripe_handle with a tmp_page - just wait until then. 2264 */ 2265 if (tmp_page) { 2266 if (failed == q_failed) { 2267 /* The only possible failed device holds 'Q', so it makes 2268 * sense to check P (If anything else were failed, we would 2269 * have used P to recreate it). 2270 */ 2271 compute_block_1(sh, pd_idx, 1); 2272 if (!page_is_zero(sh->dev[pd_idx].page)) { 2273 compute_block_1(sh,pd_idx,0); 2274 update_p = 1; 2275 } 2276 } 2277 if (!q_failed && failed < 2) { 2278 /* q is not failed, and we didn't use it to generate 2279 * anything, so it makes sense to check it 2280 */ 2281 memcpy(page_address(tmp_page), 2282 page_address(sh->dev[qd_idx].page), 2283 STRIPE_SIZE); 2284 compute_parity6(sh, UPDATE_PARITY); 2285 if (memcmp(page_address(tmp_page), 2286 page_address(sh->dev[qd_idx].page), 2287 STRIPE_SIZE)!= 0) { 2288 clear_bit(STRIPE_INSYNC, &sh->state); 2289 update_q = 1; 2290 } 2291 } 2292 if (update_p || update_q) { 2293 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2294 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2295 /* don't try to repair!! */ 2296 update_p = update_q = 0; 2297 } 2298 2299 /* now write out any block on a failed drive, 2300 * or P or Q if they need it 2301 */ 2302 2303 if (failed == 2) { 2304 dev = &sh->dev[failed_num[1]]; 2305 locked++; 2306 set_bit(R5_LOCKED, &dev->flags); 2307 set_bit(R5_Wantwrite, &dev->flags); 2308 } 2309 if (failed >= 1) { 2310 dev = &sh->dev[failed_num[0]]; 2311 locked++; 2312 set_bit(R5_LOCKED, &dev->flags); 2313 set_bit(R5_Wantwrite, &dev->flags); 2314 } 2315 2316 if (update_p) { 2317 dev = &sh->dev[pd_idx]; 2318 locked ++; 2319 set_bit(R5_LOCKED, &dev->flags); 2320 set_bit(R5_Wantwrite, &dev->flags); 2321 } 2322 if (update_q) { 2323 dev = &sh->dev[qd_idx]; 2324 locked++; 2325 set_bit(R5_LOCKED, &dev->flags); 2326 set_bit(R5_Wantwrite, &dev->flags); 2327 } 2328 clear_bit(STRIPE_DEGRADED, &sh->state); 2329 2330 set_bit(STRIPE_INSYNC, &sh->state); 2331 } 2332 } 2333 2334 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 2335 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 2336 clear_bit(STRIPE_SYNCING, &sh->state); 2337 } 2338 2339 /* If the failed drives are just a ReadError, then we might need 2340 * to progress the repair/check process 2341 */ 2342 if (failed <= 2 && ! conf->mddev->ro) 2343 for (i=0; i<failed;i++) { 2344 dev = &sh->dev[failed_num[i]]; 2345 if (test_bit(R5_ReadError, &dev->flags) 2346 && !test_bit(R5_LOCKED, &dev->flags) 2347 && test_bit(R5_UPTODATE, &dev->flags) 2348 ) { 2349 if (!test_bit(R5_ReWrite, &dev->flags)) { 2350 set_bit(R5_Wantwrite, &dev->flags); 2351 set_bit(R5_ReWrite, &dev->flags); 2352 set_bit(R5_LOCKED, &dev->flags); 2353 } else { 2354 /* let's read it back */ 2355 set_bit(R5_Wantread, &dev->flags); 2356 set_bit(R5_LOCKED, &dev->flags); 2357 } 2358 } 2359 } 2360 2361 if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) { 2362 /* Need to write out all blocks after computing P&Q */ 2363 sh->disks = conf->raid_disks; 2364 sh->pd_idx = stripe_to_pdidx(sh->sector, conf, 2365 conf->raid_disks); 2366 compute_parity6(sh, RECONSTRUCT_WRITE); 2367 for (i = conf->raid_disks ; i-- ; ) { 2368 set_bit(R5_LOCKED, &sh->dev[i].flags); 2369 locked++; 2370 set_bit(R5_Wantwrite, &sh->dev[i].flags); 2371 } 2372 clear_bit(STRIPE_EXPANDING, &sh->state); 2373 } else if (expanded) { 2374 clear_bit(STRIPE_EXPAND_READY, &sh->state); 2375 atomic_dec(&conf->reshape_stripes); 2376 wake_up(&conf->wait_for_overlap); 2377 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 2378 } 2379 2380 if (expanding && locked == 0) { 2381 /* We have read all the blocks in this stripe and now we need to 2382 * copy some of them into a target stripe for expand. 2383 */ 2384 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2385 for (i = 0; i < sh->disks ; i++) 2386 if (i != pd_idx && i != qd_idx) { 2387 int dd_idx2, pd_idx2, j; 2388 struct stripe_head *sh2; 2389 2390 sector_t bn = compute_blocknr(sh, i); 2391 sector_t s = raid5_compute_sector( 2392 bn, conf->raid_disks, 2393 conf->raid_disks - conf->max_degraded, 2394 &dd_idx2, &pd_idx2, conf); 2395 sh2 = get_active_stripe(conf, s, 2396 conf->raid_disks, 2397 pd_idx2, 1); 2398 if (sh2 == NULL) 2399 /* so for only the early blocks of 2400 * this stripe have been requests. 2401 * When later blocks get requests, we 2402 * will try again 2403 */ 2404 continue; 2405 if (!test_bit(STRIPE_EXPANDING, &sh2->state) || 2406 test_bit(R5_Expanded, 2407 &sh2->dev[dd_idx2].flags)) { 2408 /* must have already done this block */ 2409 release_stripe(sh2); 2410 continue; 2411 } 2412 memcpy(page_address(sh2->dev[dd_idx2].page), 2413 page_address(sh->dev[i].page), 2414 STRIPE_SIZE); 2415 set_bit(R5_Expanded, &sh2->dev[dd_idx2].flags); 2416 set_bit(R5_UPTODATE, &sh2->dev[dd_idx2].flags); 2417 for (j = 0 ; j < conf->raid_disks ; j++) 2418 if (j != sh2->pd_idx && 2419 j != raid6_next_disk(sh2->pd_idx, 2420 sh2->disks) && 2421 !test_bit(R5_Expanded, 2422 &sh2->dev[j].flags)) 2423 break; 2424 if (j == conf->raid_disks) { 2425 set_bit(STRIPE_EXPAND_READY, 2426 &sh2->state); 2427 set_bit(STRIPE_HANDLE, &sh2->state); 2428 } 2429 release_stripe(sh2); 2430 } 2431 } 2432 2433 spin_unlock(&sh->lock); 2434 2435 while ((bi=return_bi)) { 2436 int bytes = bi->bi_size; 2437 2438 return_bi = bi->bi_next; 2439 bi->bi_next = NULL; 2440 bi->bi_size = 0; 2441 bi->bi_end_io(bi, bytes, 2442 test_bit(BIO_UPTODATE, &bi->bi_flags) 2443 ? 0 : -EIO); 2444 } 2445 for (i=disks; i-- ;) { 2446 int rw; 2447 struct bio *bi; 2448 mdk_rdev_t *rdev; 2449 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 2450 rw = WRITE; 2451 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 2452 rw = READ; 2453 else 2454 continue; 2455 2456 bi = &sh->dev[i].req; 2457 2458 bi->bi_rw = rw; 2459 if (rw == WRITE) 2460 bi->bi_end_io = raid5_end_write_request; 2461 else 2462 bi->bi_end_io = raid5_end_read_request; 2463 2464 rcu_read_lock(); 2465 rdev = rcu_dereference(conf->disks[i].rdev); 2466 if (rdev && test_bit(Faulty, &rdev->flags)) 2467 rdev = NULL; 2468 if (rdev) 2469 atomic_inc(&rdev->nr_pending); 2470 rcu_read_unlock(); 2471 2472 if (rdev) { 2473 if (syncing || expanding || expanded) 2474 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 2475 2476 bi->bi_bdev = rdev->bdev; 2477 PRINTK("for %llu schedule op %ld on disc %d\n", 2478 (unsigned long long)sh->sector, bi->bi_rw, i); 2479 atomic_inc(&sh->count); 2480 bi->bi_sector = sh->sector + rdev->data_offset; 2481 bi->bi_flags = 1 << BIO_UPTODATE; 2482 bi->bi_vcnt = 1; 2483 bi->bi_max_vecs = 1; 2484 bi->bi_idx = 0; 2485 bi->bi_io_vec = &sh->dev[i].vec; 2486 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 2487 bi->bi_io_vec[0].bv_offset = 0; 2488 bi->bi_size = STRIPE_SIZE; 2489 bi->bi_next = NULL; 2490 if (rw == WRITE && 2491 test_bit(R5_ReWrite, &sh->dev[i].flags)) 2492 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors); 2493 generic_make_request(bi); 2494 } else { 2495 if (rw == WRITE) 2496 set_bit(STRIPE_DEGRADED, &sh->state); 2497 PRINTK("skip op %ld on disc %d for sector %llu\n", 2498 bi->bi_rw, i, (unsigned long long)sh->sector); 2499 clear_bit(R5_LOCKED, &sh->dev[i].flags); 2500 set_bit(STRIPE_HANDLE, &sh->state); 2501 } 2502 } 2503 } 2504 2505 static void handle_stripe(struct stripe_head *sh, struct page *tmp_page) 2506 { 2507 if (sh->raid_conf->level == 6) 2508 handle_stripe6(sh, tmp_page); 2509 else 2510 handle_stripe5(sh); 2511 } 2512 2513 2514 2515 static void raid5_activate_delayed(raid5_conf_t *conf) 2516 { 2517 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { 2518 while (!list_empty(&conf->delayed_list)) { 2519 struct list_head *l = conf->delayed_list.next; 2520 struct stripe_head *sh; 2521 sh = list_entry(l, struct stripe_head, lru); 2522 list_del_init(l); 2523 clear_bit(STRIPE_DELAYED, &sh->state); 2524 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 2525 atomic_inc(&conf->preread_active_stripes); 2526 list_add_tail(&sh->lru, &conf->handle_list); 2527 } 2528 } 2529 } 2530 2531 static void activate_bit_delay(raid5_conf_t *conf) 2532 { 2533 /* device_lock is held */ 2534 struct list_head head; 2535 list_add(&head, &conf->bitmap_list); 2536 list_del_init(&conf->bitmap_list); 2537 while (!list_empty(&head)) { 2538 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); 2539 list_del_init(&sh->lru); 2540 atomic_inc(&sh->count); 2541 __release_stripe(conf, sh); 2542 } 2543 } 2544 2545 static void unplug_slaves(mddev_t *mddev) 2546 { 2547 raid5_conf_t *conf = mddev_to_conf(mddev); 2548 int i; 2549 2550 rcu_read_lock(); 2551 for (i=0; i<mddev->raid_disks; i++) { 2552 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 2553 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 2554 request_queue_t *r_queue = bdev_get_queue(rdev->bdev); 2555 2556 atomic_inc(&rdev->nr_pending); 2557 rcu_read_unlock(); 2558 2559 if (r_queue->unplug_fn) 2560 r_queue->unplug_fn(r_queue); 2561 2562 rdev_dec_pending(rdev, mddev); 2563 rcu_read_lock(); 2564 } 2565 } 2566 rcu_read_unlock(); 2567 } 2568 2569 static void raid5_unplug_device(request_queue_t *q) 2570 { 2571 mddev_t *mddev = q->queuedata; 2572 raid5_conf_t *conf = mddev_to_conf(mddev); 2573 unsigned long flags; 2574 2575 spin_lock_irqsave(&conf->device_lock, flags); 2576 2577 if (blk_remove_plug(q)) { 2578 conf->seq_flush++; 2579 raid5_activate_delayed(conf); 2580 } 2581 md_wakeup_thread(mddev->thread); 2582 2583 spin_unlock_irqrestore(&conf->device_lock, flags); 2584 2585 unplug_slaves(mddev); 2586 } 2587 2588 static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk, 2589 sector_t *error_sector) 2590 { 2591 mddev_t *mddev = q->queuedata; 2592 raid5_conf_t *conf = mddev_to_conf(mddev); 2593 int i, ret = 0; 2594 2595 rcu_read_lock(); 2596 for (i=0; i<mddev->raid_disks && ret == 0; i++) { 2597 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 2598 if (rdev && !test_bit(Faulty, &rdev->flags)) { 2599 struct block_device *bdev = rdev->bdev; 2600 request_queue_t *r_queue = bdev_get_queue(bdev); 2601 2602 if (!r_queue->issue_flush_fn) 2603 ret = -EOPNOTSUPP; 2604 else { 2605 atomic_inc(&rdev->nr_pending); 2606 rcu_read_unlock(); 2607 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, 2608 error_sector); 2609 rdev_dec_pending(rdev, mddev); 2610 rcu_read_lock(); 2611 } 2612 } 2613 } 2614 rcu_read_unlock(); 2615 return ret; 2616 } 2617 2618 static int raid5_congested(void *data, int bits) 2619 { 2620 mddev_t *mddev = data; 2621 raid5_conf_t *conf = mddev_to_conf(mddev); 2622 2623 /* No difference between reads and writes. Just check 2624 * how busy the stripe_cache is 2625 */ 2626 if (conf->inactive_blocked) 2627 return 1; 2628 if (conf->quiesce) 2629 return 1; 2630 if (list_empty_careful(&conf->inactive_list)) 2631 return 1; 2632 2633 return 0; 2634 } 2635 2636 /* We want read requests to align with chunks where possible, 2637 * but write requests don't need to. 2638 */ 2639 static int raid5_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec) 2640 { 2641 mddev_t *mddev = q->queuedata; 2642 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); 2643 int max; 2644 unsigned int chunk_sectors = mddev->chunk_size >> 9; 2645 unsigned int bio_sectors = bio->bi_size >> 9; 2646 2647 if (bio_data_dir(bio) == WRITE) 2648 return biovec->bv_len; /* always allow writes to be mergeable */ 2649 2650 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; 2651 if (max < 0) max = 0; 2652 if (max <= biovec->bv_len && bio_sectors == 0) 2653 return biovec->bv_len; 2654 else 2655 return max; 2656 } 2657 2658 2659 static int in_chunk_boundary(mddev_t *mddev, struct bio *bio) 2660 { 2661 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); 2662 unsigned int chunk_sectors = mddev->chunk_size >> 9; 2663 unsigned int bio_sectors = bio->bi_size >> 9; 2664 2665 return chunk_sectors >= 2666 ((sector & (chunk_sectors - 1)) + bio_sectors); 2667 } 2668 2669 /* 2670 * add bio to the retry LIFO ( in O(1) ... we are in interrupt ) 2671 * later sampled by raid5d. 2672 */ 2673 static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf) 2674 { 2675 unsigned long flags; 2676 2677 spin_lock_irqsave(&conf->device_lock, flags); 2678 2679 bi->bi_next = conf->retry_read_aligned_list; 2680 conf->retry_read_aligned_list = bi; 2681 2682 spin_unlock_irqrestore(&conf->device_lock, flags); 2683 md_wakeup_thread(conf->mddev->thread); 2684 } 2685 2686 2687 static struct bio *remove_bio_from_retry(raid5_conf_t *conf) 2688 { 2689 struct bio *bi; 2690 2691 bi = conf->retry_read_aligned; 2692 if (bi) { 2693 conf->retry_read_aligned = NULL; 2694 return bi; 2695 } 2696 bi = conf->retry_read_aligned_list; 2697 if(bi) { 2698 conf->retry_read_aligned_list = bi->bi_next; 2699 bi->bi_next = NULL; 2700 bi->bi_phys_segments = 1; /* biased count of active stripes */ 2701 bi->bi_hw_segments = 0; /* count of processed stripes */ 2702 } 2703 2704 return bi; 2705 } 2706 2707 2708 /* 2709 * The "raid5_align_endio" should check if the read succeeded and if it 2710 * did, call bio_endio on the original bio (having bio_put the new bio 2711 * first). 2712 * If the read failed.. 2713 */ 2714 static int raid5_align_endio(struct bio *bi, unsigned int bytes, int error) 2715 { 2716 struct bio* raid_bi = bi->bi_private; 2717 mddev_t *mddev; 2718 raid5_conf_t *conf; 2719 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 2720 mdk_rdev_t *rdev; 2721 2722 if (bi->bi_size) 2723 return 1; 2724 bio_put(bi); 2725 2726 mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata; 2727 conf = mddev_to_conf(mddev); 2728 rdev = (void*)raid_bi->bi_next; 2729 raid_bi->bi_next = NULL; 2730 2731 rdev_dec_pending(rdev, conf->mddev); 2732 2733 if (!error && uptodate) { 2734 bio_endio(raid_bi, bytes, 0); 2735 if (atomic_dec_and_test(&conf->active_aligned_reads)) 2736 wake_up(&conf->wait_for_stripe); 2737 return 0; 2738 } 2739 2740 2741 PRINTK("raid5_align_endio : io error...handing IO for a retry\n"); 2742 2743 add_bio_to_retry(raid_bi, conf); 2744 return 0; 2745 } 2746 2747 static int bio_fits_rdev(struct bio *bi) 2748 { 2749 request_queue_t *q = bdev_get_queue(bi->bi_bdev); 2750 2751 if ((bi->bi_size>>9) > q->max_sectors) 2752 return 0; 2753 blk_recount_segments(q, bi); 2754 if (bi->bi_phys_segments > q->max_phys_segments || 2755 bi->bi_hw_segments > q->max_hw_segments) 2756 return 0; 2757 2758 if (q->merge_bvec_fn) 2759 /* it's too hard to apply the merge_bvec_fn at this stage, 2760 * just just give up 2761 */ 2762 return 0; 2763 2764 return 1; 2765 } 2766 2767 2768 static int chunk_aligned_read(request_queue_t *q, struct bio * raid_bio) 2769 { 2770 mddev_t *mddev = q->queuedata; 2771 raid5_conf_t *conf = mddev_to_conf(mddev); 2772 const unsigned int raid_disks = conf->raid_disks; 2773 const unsigned int data_disks = raid_disks - conf->max_degraded; 2774 unsigned int dd_idx, pd_idx; 2775 struct bio* align_bi; 2776 mdk_rdev_t *rdev; 2777 2778 if (!in_chunk_boundary(mddev, raid_bio)) { 2779 PRINTK("chunk_aligned_read : non aligned\n"); 2780 return 0; 2781 } 2782 /* 2783 * use bio_clone to make a copy of the bio 2784 */ 2785 align_bi = bio_clone(raid_bio, GFP_NOIO); 2786 if (!align_bi) 2787 return 0; 2788 /* 2789 * set bi_end_io to a new function, and set bi_private to the 2790 * original bio. 2791 */ 2792 align_bi->bi_end_io = raid5_align_endio; 2793 align_bi->bi_private = raid_bio; 2794 /* 2795 * compute position 2796 */ 2797 align_bi->bi_sector = raid5_compute_sector(raid_bio->bi_sector, 2798 raid_disks, 2799 data_disks, 2800 &dd_idx, 2801 &pd_idx, 2802 conf); 2803 2804 rcu_read_lock(); 2805 rdev = rcu_dereference(conf->disks[dd_idx].rdev); 2806 if (rdev && test_bit(In_sync, &rdev->flags)) { 2807 atomic_inc(&rdev->nr_pending); 2808 rcu_read_unlock(); 2809 raid_bio->bi_next = (void*)rdev; 2810 align_bi->bi_bdev = rdev->bdev; 2811 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID); 2812 align_bi->bi_sector += rdev->data_offset; 2813 2814 if (!bio_fits_rdev(align_bi)) { 2815 /* too big in some way */ 2816 bio_put(align_bi); 2817 rdev_dec_pending(rdev, mddev); 2818 return 0; 2819 } 2820 2821 spin_lock_irq(&conf->device_lock); 2822 wait_event_lock_irq(conf->wait_for_stripe, 2823 conf->quiesce == 0, 2824 conf->device_lock, /* nothing */); 2825 atomic_inc(&conf->active_aligned_reads); 2826 spin_unlock_irq(&conf->device_lock); 2827 2828 generic_make_request(align_bi); 2829 return 1; 2830 } else { 2831 rcu_read_unlock(); 2832 bio_put(align_bi); 2833 return 0; 2834 } 2835 } 2836 2837 2838 static int make_request(request_queue_t *q, struct bio * bi) 2839 { 2840 mddev_t *mddev = q->queuedata; 2841 raid5_conf_t *conf = mddev_to_conf(mddev); 2842 unsigned int dd_idx, pd_idx; 2843 sector_t new_sector; 2844 sector_t logical_sector, last_sector; 2845 struct stripe_head *sh; 2846 const int rw = bio_data_dir(bi); 2847 int remaining; 2848 2849 if (unlikely(bio_barrier(bi))) { 2850 bio_endio(bi, bi->bi_size, -EOPNOTSUPP); 2851 return 0; 2852 } 2853 2854 md_write_start(mddev, bi); 2855 2856 disk_stat_inc(mddev->gendisk, ios[rw]); 2857 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi)); 2858 2859 if (rw == READ && 2860 mddev->reshape_position == MaxSector && 2861 chunk_aligned_read(q,bi)) 2862 return 0; 2863 2864 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 2865 last_sector = bi->bi_sector + (bi->bi_size>>9); 2866 bi->bi_next = NULL; 2867 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ 2868 2869 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { 2870 DEFINE_WAIT(w); 2871 int disks, data_disks; 2872 2873 retry: 2874 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); 2875 if (likely(conf->expand_progress == MaxSector)) 2876 disks = conf->raid_disks; 2877 else { 2878 /* spinlock is needed as expand_progress may be 2879 * 64bit on a 32bit platform, and so it might be 2880 * possible to see a half-updated value 2881 * Ofcourse expand_progress could change after 2882 * the lock is dropped, so once we get a reference 2883 * to the stripe that we think it is, we will have 2884 * to check again. 2885 */ 2886 spin_lock_irq(&conf->device_lock); 2887 disks = conf->raid_disks; 2888 if (logical_sector >= conf->expand_progress) 2889 disks = conf->previous_raid_disks; 2890 else { 2891 if (logical_sector >= conf->expand_lo) { 2892 spin_unlock_irq(&conf->device_lock); 2893 schedule(); 2894 goto retry; 2895 } 2896 } 2897 spin_unlock_irq(&conf->device_lock); 2898 } 2899 data_disks = disks - conf->max_degraded; 2900 2901 new_sector = raid5_compute_sector(logical_sector, disks, data_disks, 2902 &dd_idx, &pd_idx, conf); 2903 PRINTK("raid5: make_request, sector %llu logical %llu\n", 2904 (unsigned long long)new_sector, 2905 (unsigned long long)logical_sector); 2906 2907 sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK)); 2908 if (sh) { 2909 if (unlikely(conf->expand_progress != MaxSector)) { 2910 /* expansion might have moved on while waiting for a 2911 * stripe, so we must do the range check again. 2912 * Expansion could still move past after this 2913 * test, but as we are holding a reference to 2914 * 'sh', we know that if that happens, 2915 * STRIPE_EXPANDING will get set and the expansion 2916 * won't proceed until we finish with the stripe. 2917 */ 2918 int must_retry = 0; 2919 spin_lock_irq(&conf->device_lock); 2920 if (logical_sector < conf->expand_progress && 2921 disks == conf->previous_raid_disks) 2922 /* mismatch, need to try again */ 2923 must_retry = 1; 2924 spin_unlock_irq(&conf->device_lock); 2925 if (must_retry) { 2926 release_stripe(sh); 2927 goto retry; 2928 } 2929 } 2930 /* FIXME what if we get a false positive because these 2931 * are being updated. 2932 */ 2933 if (logical_sector >= mddev->suspend_lo && 2934 logical_sector < mddev->suspend_hi) { 2935 release_stripe(sh); 2936 schedule(); 2937 goto retry; 2938 } 2939 2940 if (test_bit(STRIPE_EXPANDING, &sh->state) || 2941 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { 2942 /* Stripe is busy expanding or 2943 * add failed due to overlap. Flush everything 2944 * and wait a while 2945 */ 2946 raid5_unplug_device(mddev->queue); 2947 release_stripe(sh); 2948 schedule(); 2949 goto retry; 2950 } 2951 finish_wait(&conf->wait_for_overlap, &w); 2952 handle_stripe(sh, NULL); 2953 release_stripe(sh); 2954 } else { 2955 /* cannot get stripe for read-ahead, just give-up */ 2956 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2957 finish_wait(&conf->wait_for_overlap, &w); 2958 break; 2959 } 2960 2961 } 2962 spin_lock_irq(&conf->device_lock); 2963 remaining = --bi->bi_phys_segments; 2964 spin_unlock_irq(&conf->device_lock); 2965 if (remaining == 0) { 2966 int bytes = bi->bi_size; 2967 2968 if ( rw == WRITE ) 2969 md_write_end(mddev); 2970 bi->bi_size = 0; 2971 bi->bi_end_io(bi, bytes, 2972 test_bit(BIO_UPTODATE, &bi->bi_flags) 2973 ? 0 : -EIO); 2974 } 2975 return 0; 2976 } 2977 2978 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped) 2979 { 2980 /* reshaping is quite different to recovery/resync so it is 2981 * handled quite separately ... here. 2982 * 2983 * On each call to sync_request, we gather one chunk worth of 2984 * destination stripes and flag them as expanding. 2985 * Then we find all the source stripes and request reads. 2986 * As the reads complete, handle_stripe will copy the data 2987 * into the destination stripe and release that stripe. 2988 */ 2989 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 2990 struct stripe_head *sh; 2991 int pd_idx; 2992 sector_t first_sector, last_sector; 2993 int raid_disks = conf->previous_raid_disks; 2994 int data_disks = raid_disks - conf->max_degraded; 2995 int new_data_disks = conf->raid_disks - conf->max_degraded; 2996 int i; 2997 int dd_idx; 2998 sector_t writepos, safepos, gap; 2999 3000 if (sector_nr == 0 && 3001 conf->expand_progress != 0) { 3002 /* restarting in the middle, skip the initial sectors */ 3003 sector_nr = conf->expand_progress; 3004 sector_div(sector_nr, new_data_disks); 3005 *skipped = 1; 3006 return sector_nr; 3007 } 3008 3009 /* we update the metadata when there is more than 3Meg 3010 * in the block range (that is rather arbitrary, should 3011 * probably be time based) or when the data about to be 3012 * copied would over-write the source of the data at 3013 * the front of the range. 3014 * i.e. one new_stripe forward from expand_progress new_maps 3015 * to after where expand_lo old_maps to 3016 */ 3017 writepos = conf->expand_progress + 3018 conf->chunk_size/512*(new_data_disks); 3019 sector_div(writepos, new_data_disks); 3020 safepos = conf->expand_lo; 3021 sector_div(safepos, data_disks); 3022 gap = conf->expand_progress - conf->expand_lo; 3023 3024 if (writepos >= safepos || 3025 gap > (new_data_disks)*3000*2 /*3Meg*/) { 3026 /* Cannot proceed until we've updated the superblock... */ 3027 wait_event(conf->wait_for_overlap, 3028 atomic_read(&conf->reshape_stripes)==0); 3029 mddev->reshape_position = conf->expand_progress; 3030 set_bit(MD_CHANGE_DEVS, &mddev->flags); 3031 md_wakeup_thread(mddev->thread); 3032 wait_event(mddev->sb_wait, mddev->flags == 0 || 3033 kthread_should_stop()); 3034 spin_lock_irq(&conf->device_lock); 3035 conf->expand_lo = mddev->reshape_position; 3036 spin_unlock_irq(&conf->device_lock); 3037 wake_up(&conf->wait_for_overlap); 3038 } 3039 3040 for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) { 3041 int j; 3042 int skipped = 0; 3043 pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks); 3044 sh = get_active_stripe(conf, sector_nr+i, 3045 conf->raid_disks, pd_idx, 0); 3046 set_bit(STRIPE_EXPANDING, &sh->state); 3047 atomic_inc(&conf->reshape_stripes); 3048 /* If any of this stripe is beyond the end of the old 3049 * array, then we need to zero those blocks 3050 */ 3051 for (j=sh->disks; j--;) { 3052 sector_t s; 3053 if (j == sh->pd_idx) 3054 continue; 3055 if (conf->level == 6 && 3056 j == raid6_next_disk(sh->pd_idx, sh->disks)) 3057 continue; 3058 s = compute_blocknr(sh, j); 3059 if (s < (mddev->array_size<<1)) { 3060 skipped = 1; 3061 continue; 3062 } 3063 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE); 3064 set_bit(R5_Expanded, &sh->dev[j].flags); 3065 set_bit(R5_UPTODATE, &sh->dev[j].flags); 3066 } 3067 if (!skipped) { 3068 set_bit(STRIPE_EXPAND_READY, &sh->state); 3069 set_bit(STRIPE_HANDLE, &sh->state); 3070 } 3071 release_stripe(sh); 3072 } 3073 spin_lock_irq(&conf->device_lock); 3074 conf->expand_progress = (sector_nr + i) * new_data_disks; 3075 spin_unlock_irq(&conf->device_lock); 3076 /* Ok, those stripe are ready. We can start scheduling 3077 * reads on the source stripes. 3078 * The source stripes are determined by mapping the first and last 3079 * block on the destination stripes. 3080 */ 3081 first_sector = 3082 raid5_compute_sector(sector_nr*(new_data_disks), 3083 raid_disks, data_disks, 3084 &dd_idx, &pd_idx, conf); 3085 last_sector = 3086 raid5_compute_sector((sector_nr+conf->chunk_size/512) 3087 *(new_data_disks) -1, 3088 raid_disks, data_disks, 3089 &dd_idx, &pd_idx, conf); 3090 if (last_sector >= (mddev->size<<1)) 3091 last_sector = (mddev->size<<1)-1; 3092 while (first_sector <= last_sector) { 3093 pd_idx = stripe_to_pdidx(first_sector, conf, 3094 conf->previous_raid_disks); 3095 sh = get_active_stripe(conf, first_sector, 3096 conf->previous_raid_disks, pd_idx, 0); 3097 set_bit(STRIPE_EXPAND_SOURCE, &sh->state); 3098 set_bit(STRIPE_HANDLE, &sh->state); 3099 release_stripe(sh); 3100 first_sector += STRIPE_SECTORS; 3101 } 3102 return conf->chunk_size>>9; 3103 } 3104 3105 /* FIXME go_faster isn't used */ 3106 static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 3107 { 3108 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 3109 struct stripe_head *sh; 3110 int pd_idx; 3111 int raid_disks = conf->raid_disks; 3112 sector_t max_sector = mddev->size << 1; 3113 int sync_blocks; 3114 int still_degraded = 0; 3115 int i; 3116 3117 if (sector_nr >= max_sector) { 3118 /* just being told to finish up .. nothing much to do */ 3119 unplug_slaves(mddev); 3120 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) { 3121 end_reshape(conf); 3122 return 0; 3123 } 3124 3125 if (mddev->curr_resync < max_sector) /* aborted */ 3126 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 3127 &sync_blocks, 1); 3128 else /* completed sync */ 3129 conf->fullsync = 0; 3130 bitmap_close_sync(mddev->bitmap); 3131 3132 return 0; 3133 } 3134 3135 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) 3136 return reshape_request(mddev, sector_nr, skipped); 3137 3138 /* if there is too many failed drives and we are trying 3139 * to resync, then assert that we are finished, because there is 3140 * nothing we can do. 3141 */ 3142 if (mddev->degraded >= conf->max_degraded && 3143 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 3144 sector_t rv = (mddev->size << 1) - sector_nr; 3145 *skipped = 1; 3146 return rv; 3147 } 3148 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && 3149 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && 3150 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { 3151 /* we can skip this block, and probably more */ 3152 sync_blocks /= STRIPE_SECTORS; 3153 *skipped = 1; 3154 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ 3155 } 3156 3157 pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks); 3158 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1); 3159 if (sh == NULL) { 3160 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0); 3161 /* make sure we don't swamp the stripe cache if someone else 3162 * is trying to get access 3163 */ 3164 schedule_timeout_uninterruptible(1); 3165 } 3166 /* Need to check if array will still be degraded after recovery/resync 3167 * We don't need to check the 'failed' flag as when that gets set, 3168 * recovery aborts. 3169 */ 3170 for (i=0; i<mddev->raid_disks; i++) 3171 if (conf->disks[i].rdev == NULL) 3172 still_degraded = 1; 3173 3174 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded); 3175 3176 spin_lock(&sh->lock); 3177 set_bit(STRIPE_SYNCING, &sh->state); 3178 clear_bit(STRIPE_INSYNC, &sh->state); 3179 spin_unlock(&sh->lock); 3180 3181 handle_stripe(sh, NULL); 3182 release_stripe(sh); 3183 3184 return STRIPE_SECTORS; 3185 } 3186 3187 static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) 3188 { 3189 /* We may not be able to submit a whole bio at once as there 3190 * may not be enough stripe_heads available. 3191 * We cannot pre-allocate enough stripe_heads as we may need 3192 * more than exist in the cache (if we allow ever large chunks). 3193 * So we do one stripe head at a time and record in 3194 * ->bi_hw_segments how many have been done. 3195 * 3196 * We *know* that this entire raid_bio is in one chunk, so 3197 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector. 3198 */ 3199 struct stripe_head *sh; 3200 int dd_idx, pd_idx; 3201 sector_t sector, logical_sector, last_sector; 3202 int scnt = 0; 3203 int remaining; 3204 int handled = 0; 3205 3206 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 3207 sector = raid5_compute_sector( logical_sector, 3208 conf->raid_disks, 3209 conf->raid_disks - conf->max_degraded, 3210 &dd_idx, 3211 &pd_idx, 3212 conf); 3213 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9); 3214 3215 for (; logical_sector < last_sector; 3216 logical_sector += STRIPE_SECTORS, 3217 sector += STRIPE_SECTORS, 3218 scnt++) { 3219 3220 if (scnt < raid_bio->bi_hw_segments) 3221 /* already done this stripe */ 3222 continue; 3223 3224 sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1); 3225 3226 if (!sh) { 3227 /* failed to get a stripe - must wait */ 3228 raid_bio->bi_hw_segments = scnt; 3229 conf->retry_read_aligned = raid_bio; 3230 return handled; 3231 } 3232 3233 set_bit(R5_ReadError, &sh->dev[dd_idx].flags); 3234 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) { 3235 release_stripe(sh); 3236 raid_bio->bi_hw_segments = scnt; 3237 conf->retry_read_aligned = raid_bio; 3238 return handled; 3239 } 3240 3241 handle_stripe(sh, NULL); 3242 release_stripe(sh); 3243 handled++; 3244 } 3245 spin_lock_irq(&conf->device_lock); 3246 remaining = --raid_bio->bi_phys_segments; 3247 spin_unlock_irq(&conf->device_lock); 3248 if (remaining == 0) { 3249 int bytes = raid_bio->bi_size; 3250 3251 raid_bio->bi_size = 0; 3252 raid_bio->bi_end_io(raid_bio, bytes, 3253 test_bit(BIO_UPTODATE, &raid_bio->bi_flags) 3254 ? 0 : -EIO); 3255 } 3256 if (atomic_dec_and_test(&conf->active_aligned_reads)) 3257 wake_up(&conf->wait_for_stripe); 3258 return handled; 3259 } 3260 3261 3262 3263 /* 3264 * This is our raid5 kernel thread. 3265 * 3266 * We scan the hash table for stripes which can be handled now. 3267 * During the scan, completed stripes are saved for us by the interrupt 3268 * handler, so that they will not have to wait for our next wakeup. 3269 */ 3270 static void raid5d (mddev_t *mddev) 3271 { 3272 struct stripe_head *sh; 3273 raid5_conf_t *conf = mddev_to_conf(mddev); 3274 int handled; 3275 3276 PRINTK("+++ raid5d active\n"); 3277 3278 md_check_recovery(mddev); 3279 3280 handled = 0; 3281 spin_lock_irq(&conf->device_lock); 3282 while (1) { 3283 struct list_head *first; 3284 struct bio *bio; 3285 3286 if (conf->seq_flush != conf->seq_write) { 3287 int seq = conf->seq_flush; 3288 spin_unlock_irq(&conf->device_lock); 3289 bitmap_unplug(mddev->bitmap); 3290 spin_lock_irq(&conf->device_lock); 3291 conf->seq_write = seq; 3292 activate_bit_delay(conf); 3293 } 3294 3295 if (list_empty(&conf->handle_list) && 3296 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD && 3297 !blk_queue_plugged(mddev->queue) && 3298 !list_empty(&conf->delayed_list)) 3299 raid5_activate_delayed(conf); 3300 3301 while ((bio = remove_bio_from_retry(conf))) { 3302 int ok; 3303 spin_unlock_irq(&conf->device_lock); 3304 ok = retry_aligned_read(conf, bio); 3305 spin_lock_irq(&conf->device_lock); 3306 if (!ok) 3307 break; 3308 handled++; 3309 } 3310 3311 if (list_empty(&conf->handle_list)) 3312 break; 3313 3314 first = conf->handle_list.next; 3315 sh = list_entry(first, struct stripe_head, lru); 3316 3317 list_del_init(first); 3318 atomic_inc(&sh->count); 3319 BUG_ON(atomic_read(&sh->count)!= 1); 3320 spin_unlock_irq(&conf->device_lock); 3321 3322 handled++; 3323 handle_stripe(sh, conf->spare_page); 3324 release_stripe(sh); 3325 3326 spin_lock_irq(&conf->device_lock); 3327 } 3328 PRINTK("%d stripes handled\n", handled); 3329 3330 spin_unlock_irq(&conf->device_lock); 3331 3332 unplug_slaves(mddev); 3333 3334 PRINTK("--- raid5d inactive\n"); 3335 } 3336 3337 static ssize_t 3338 raid5_show_stripe_cache_size(mddev_t *mddev, char *page) 3339 { 3340 raid5_conf_t *conf = mddev_to_conf(mddev); 3341 if (conf) 3342 return sprintf(page, "%d\n", conf->max_nr_stripes); 3343 else 3344 return 0; 3345 } 3346 3347 static ssize_t 3348 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 3349 { 3350 raid5_conf_t *conf = mddev_to_conf(mddev); 3351 char *end; 3352 int new; 3353 if (len >= PAGE_SIZE) 3354 return -EINVAL; 3355 if (!conf) 3356 return -ENODEV; 3357 3358 new = simple_strtoul(page, &end, 10); 3359 if (!*page || (*end && *end != '\n') ) 3360 return -EINVAL; 3361 if (new <= 16 || new > 32768) 3362 return -EINVAL; 3363 while (new < conf->max_nr_stripes) { 3364 if (drop_one_stripe(conf)) 3365 conf->max_nr_stripes--; 3366 else 3367 break; 3368 } 3369 md_allow_write(mddev); 3370 while (new > conf->max_nr_stripes) { 3371 if (grow_one_stripe(conf)) 3372 conf->max_nr_stripes++; 3373 else break; 3374 } 3375 return len; 3376 } 3377 3378 static struct md_sysfs_entry 3379 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, 3380 raid5_show_stripe_cache_size, 3381 raid5_store_stripe_cache_size); 3382 3383 static ssize_t 3384 stripe_cache_active_show(mddev_t *mddev, char *page) 3385 { 3386 raid5_conf_t *conf = mddev_to_conf(mddev); 3387 if (conf) 3388 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes)); 3389 else 3390 return 0; 3391 } 3392 3393 static struct md_sysfs_entry 3394 raid5_stripecache_active = __ATTR_RO(stripe_cache_active); 3395 3396 static struct attribute *raid5_attrs[] = { 3397 &raid5_stripecache_size.attr, 3398 &raid5_stripecache_active.attr, 3399 NULL, 3400 }; 3401 static struct attribute_group raid5_attrs_group = { 3402 .name = NULL, 3403 .attrs = raid5_attrs, 3404 }; 3405 3406 static int run(mddev_t *mddev) 3407 { 3408 raid5_conf_t *conf; 3409 int raid_disk, memory; 3410 mdk_rdev_t *rdev; 3411 struct disk_info *disk; 3412 struct list_head *tmp; 3413 int working_disks = 0; 3414 3415 if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) { 3416 printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n", 3417 mdname(mddev), mddev->level); 3418 return -EIO; 3419 } 3420 3421 if (mddev->reshape_position != MaxSector) { 3422 /* Check that we can continue the reshape. 3423 * Currently only disks can change, it must 3424 * increase, and we must be past the point where 3425 * a stripe over-writes itself 3426 */ 3427 sector_t here_new, here_old; 3428 int old_disks; 3429 int max_degraded = (mddev->level == 5 ? 1 : 2); 3430 3431 if (mddev->new_level != mddev->level || 3432 mddev->new_layout != mddev->layout || 3433 mddev->new_chunk != mddev->chunk_size) { 3434 printk(KERN_ERR "raid5: %s: unsupported reshape " 3435 "required - aborting.\n", 3436 mdname(mddev)); 3437 return -EINVAL; 3438 } 3439 if (mddev->delta_disks <= 0) { 3440 printk(KERN_ERR "raid5: %s: unsupported reshape " 3441 "(reduce disks) required - aborting.\n", 3442 mdname(mddev)); 3443 return -EINVAL; 3444 } 3445 old_disks = mddev->raid_disks - mddev->delta_disks; 3446 /* reshape_position must be on a new-stripe boundary, and one 3447 * further up in new geometry must map after here in old 3448 * geometry. 3449 */ 3450 here_new = mddev->reshape_position; 3451 if (sector_div(here_new, (mddev->chunk_size>>9)* 3452 (mddev->raid_disks - max_degraded))) { 3453 printk(KERN_ERR "raid5: reshape_position not " 3454 "on a stripe boundary\n"); 3455 return -EINVAL; 3456 } 3457 /* here_new is the stripe we will write to */ 3458 here_old = mddev->reshape_position; 3459 sector_div(here_old, (mddev->chunk_size>>9)* 3460 (old_disks-max_degraded)); 3461 /* here_old is the first stripe that we might need to read 3462 * from */ 3463 if (here_new >= here_old) { 3464 /* Reading from the same stripe as writing to - bad */ 3465 printk(KERN_ERR "raid5: reshape_position too early for " 3466 "auto-recovery - aborting.\n"); 3467 return -EINVAL; 3468 } 3469 printk(KERN_INFO "raid5: reshape will continue\n"); 3470 /* OK, we should be able to continue; */ 3471 } 3472 3473 3474 mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL); 3475 if ((conf = mddev->private) == NULL) 3476 goto abort; 3477 if (mddev->reshape_position == MaxSector) { 3478 conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks; 3479 } else { 3480 conf->raid_disks = mddev->raid_disks; 3481 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks; 3482 } 3483 3484 conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info), 3485 GFP_KERNEL); 3486 if (!conf->disks) 3487 goto abort; 3488 3489 conf->mddev = mddev; 3490 3491 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) 3492 goto abort; 3493 3494 if (mddev->level == 6) { 3495 conf->spare_page = alloc_page(GFP_KERNEL); 3496 if (!conf->spare_page) 3497 goto abort; 3498 } 3499 spin_lock_init(&conf->device_lock); 3500 init_waitqueue_head(&conf->wait_for_stripe); 3501 init_waitqueue_head(&conf->wait_for_overlap); 3502 INIT_LIST_HEAD(&conf->handle_list); 3503 INIT_LIST_HEAD(&conf->delayed_list); 3504 INIT_LIST_HEAD(&conf->bitmap_list); 3505 INIT_LIST_HEAD(&conf->inactive_list); 3506 atomic_set(&conf->active_stripes, 0); 3507 atomic_set(&conf->preread_active_stripes, 0); 3508 atomic_set(&conf->active_aligned_reads, 0); 3509 3510 PRINTK("raid5: run(%s) called.\n", mdname(mddev)); 3511 3512 ITERATE_RDEV(mddev,rdev,tmp) { 3513 raid_disk = rdev->raid_disk; 3514 if (raid_disk >= conf->raid_disks 3515 || raid_disk < 0) 3516 continue; 3517 disk = conf->disks + raid_disk; 3518 3519 disk->rdev = rdev; 3520 3521 if (test_bit(In_sync, &rdev->flags)) { 3522 char b[BDEVNAME_SIZE]; 3523 printk(KERN_INFO "raid5: device %s operational as raid" 3524 " disk %d\n", bdevname(rdev->bdev,b), 3525 raid_disk); 3526 working_disks++; 3527 } 3528 } 3529 3530 /* 3531 * 0 for a fully functional array, 1 or 2 for a degraded array. 3532 */ 3533 mddev->degraded = conf->raid_disks - working_disks; 3534 conf->mddev = mddev; 3535 conf->chunk_size = mddev->chunk_size; 3536 conf->level = mddev->level; 3537 if (conf->level == 6) 3538 conf->max_degraded = 2; 3539 else 3540 conf->max_degraded = 1; 3541 conf->algorithm = mddev->layout; 3542 conf->max_nr_stripes = NR_STRIPES; 3543 conf->expand_progress = mddev->reshape_position; 3544 3545 /* device size must be a multiple of chunk size */ 3546 mddev->size &= ~(mddev->chunk_size/1024 -1); 3547 mddev->resync_max_sectors = mddev->size << 1; 3548 3549 if (conf->level == 6 && conf->raid_disks < 4) { 3550 printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n", 3551 mdname(mddev), conf->raid_disks); 3552 goto abort; 3553 } 3554 if (!conf->chunk_size || conf->chunk_size % 4) { 3555 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", 3556 conf->chunk_size, mdname(mddev)); 3557 goto abort; 3558 } 3559 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) { 3560 printk(KERN_ERR 3561 "raid5: unsupported parity algorithm %d for %s\n", 3562 conf->algorithm, mdname(mddev)); 3563 goto abort; 3564 } 3565 if (mddev->degraded > conf->max_degraded) { 3566 printk(KERN_ERR "raid5: not enough operational devices for %s" 3567 " (%d/%d failed)\n", 3568 mdname(mddev), mddev->degraded, conf->raid_disks); 3569 goto abort; 3570 } 3571 3572 if (mddev->degraded > 0 && 3573 mddev->recovery_cp != MaxSector) { 3574 if (mddev->ok_start_degraded) 3575 printk(KERN_WARNING 3576 "raid5: starting dirty degraded array: %s" 3577 "- data corruption possible.\n", 3578 mdname(mddev)); 3579 else { 3580 printk(KERN_ERR 3581 "raid5: cannot start dirty degraded array for %s\n", 3582 mdname(mddev)); 3583 goto abort; 3584 } 3585 } 3586 3587 { 3588 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5"); 3589 if (!mddev->thread) { 3590 printk(KERN_ERR 3591 "raid5: couldn't allocate thread for %s\n", 3592 mdname(mddev)); 3593 goto abort; 3594 } 3595 } 3596 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + 3597 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; 3598 if (grow_stripes(conf, conf->max_nr_stripes)) { 3599 printk(KERN_ERR 3600 "raid5: couldn't allocate %dkB for buffers\n", memory); 3601 shrink_stripes(conf); 3602 md_unregister_thread(mddev->thread); 3603 goto abort; 3604 } else 3605 printk(KERN_INFO "raid5: allocated %dkB for %s\n", 3606 memory, mdname(mddev)); 3607 3608 if (mddev->degraded == 0) 3609 printk("raid5: raid level %d set %s active with %d out of %d" 3610 " devices, algorithm %d\n", conf->level, mdname(mddev), 3611 mddev->raid_disks-mddev->degraded, mddev->raid_disks, 3612 conf->algorithm); 3613 else 3614 printk(KERN_ALERT "raid5: raid level %d set %s active with %d" 3615 " out of %d devices, algorithm %d\n", conf->level, 3616 mdname(mddev), mddev->raid_disks - mddev->degraded, 3617 mddev->raid_disks, conf->algorithm); 3618 3619 print_raid5_conf(conf); 3620 3621 if (conf->expand_progress != MaxSector) { 3622 printk("...ok start reshape thread\n"); 3623 conf->expand_lo = conf->expand_progress; 3624 atomic_set(&conf->reshape_stripes, 0); 3625 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 3626 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 3627 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 3628 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 3629 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 3630 "%s_reshape"); 3631 } 3632 3633 /* read-ahead size must cover two whole stripes, which is 3634 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 3635 */ 3636 { 3637 int data_disks = conf->previous_raid_disks - conf->max_degraded; 3638 int stripe = data_disks * 3639 (mddev->chunk_size / PAGE_SIZE); 3640 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 3641 mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 3642 } 3643 3644 /* Ok, everything is just fine now */ 3645 if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group)) 3646 printk(KERN_WARNING 3647 "raid5: failed to create sysfs attributes for %s\n", 3648 mdname(mddev)); 3649 3650 mddev->queue->unplug_fn = raid5_unplug_device; 3651 mddev->queue->issue_flush_fn = raid5_issue_flush; 3652 mddev->queue->backing_dev_info.congested_data = mddev; 3653 mddev->queue->backing_dev_info.congested_fn = raid5_congested; 3654 3655 mddev->array_size = mddev->size * (conf->previous_raid_disks - 3656 conf->max_degraded); 3657 3658 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); 3659 3660 return 0; 3661 abort: 3662 if (conf) { 3663 print_raid5_conf(conf); 3664 safe_put_page(conf->spare_page); 3665 kfree(conf->disks); 3666 kfree(conf->stripe_hashtbl); 3667 kfree(conf); 3668 } 3669 mddev->private = NULL; 3670 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); 3671 return -EIO; 3672 } 3673 3674 3675 3676 static int stop(mddev_t *mddev) 3677 { 3678 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 3679 3680 md_unregister_thread(mddev->thread); 3681 mddev->thread = NULL; 3682 shrink_stripes(conf); 3683 kfree(conf->stripe_hashtbl); 3684 mddev->queue->backing_dev_info.congested_fn = NULL; 3685 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 3686 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group); 3687 kfree(conf->disks); 3688 kfree(conf); 3689 mddev->private = NULL; 3690 return 0; 3691 } 3692 3693 #if RAID5_DEBUG 3694 static void print_sh (struct seq_file *seq, struct stripe_head *sh) 3695 { 3696 int i; 3697 3698 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n", 3699 (unsigned long long)sh->sector, sh->pd_idx, sh->state); 3700 seq_printf(seq, "sh %llu, count %d.\n", 3701 (unsigned long long)sh->sector, atomic_read(&sh->count)); 3702 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector); 3703 for (i = 0; i < sh->disks; i++) { 3704 seq_printf(seq, "(cache%d: %p %ld) ", 3705 i, sh->dev[i].page, sh->dev[i].flags); 3706 } 3707 seq_printf(seq, "\n"); 3708 } 3709 3710 static void printall (struct seq_file *seq, raid5_conf_t *conf) 3711 { 3712 struct stripe_head *sh; 3713 struct hlist_node *hn; 3714 int i; 3715 3716 spin_lock_irq(&conf->device_lock); 3717 for (i = 0; i < NR_HASH; i++) { 3718 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) { 3719 if (sh->raid_conf != conf) 3720 continue; 3721 print_sh(seq, sh); 3722 } 3723 } 3724 spin_unlock_irq(&conf->device_lock); 3725 } 3726 #endif 3727 3728 static void status (struct seq_file *seq, mddev_t *mddev) 3729 { 3730 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 3731 int i; 3732 3733 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout); 3734 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); 3735 for (i = 0; i < conf->raid_disks; i++) 3736 seq_printf (seq, "%s", 3737 conf->disks[i].rdev && 3738 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_"); 3739 seq_printf (seq, "]"); 3740 #if RAID5_DEBUG 3741 seq_printf (seq, "\n"); 3742 printall(seq, conf); 3743 #endif 3744 } 3745 3746 static void print_raid5_conf (raid5_conf_t *conf) 3747 { 3748 int i; 3749 struct disk_info *tmp; 3750 3751 printk("RAID5 conf printout:\n"); 3752 if (!conf) { 3753 printk("(conf==NULL)\n"); 3754 return; 3755 } 3756 printk(" --- rd:%d wd:%d\n", conf->raid_disks, 3757 conf->raid_disks - conf->mddev->degraded); 3758 3759 for (i = 0; i < conf->raid_disks; i++) { 3760 char b[BDEVNAME_SIZE]; 3761 tmp = conf->disks + i; 3762 if (tmp->rdev) 3763 printk(" disk %d, o:%d, dev:%s\n", 3764 i, !test_bit(Faulty, &tmp->rdev->flags), 3765 bdevname(tmp->rdev->bdev,b)); 3766 } 3767 } 3768 3769 static int raid5_spare_active(mddev_t *mddev) 3770 { 3771 int i; 3772 raid5_conf_t *conf = mddev->private; 3773 struct disk_info *tmp; 3774 3775 for (i = 0; i < conf->raid_disks; i++) { 3776 tmp = conf->disks + i; 3777 if (tmp->rdev 3778 && !test_bit(Faulty, &tmp->rdev->flags) 3779 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 3780 unsigned long flags; 3781 spin_lock_irqsave(&conf->device_lock, flags); 3782 mddev->degraded--; 3783 spin_unlock_irqrestore(&conf->device_lock, flags); 3784 } 3785 } 3786 print_raid5_conf(conf); 3787 return 0; 3788 } 3789 3790 static int raid5_remove_disk(mddev_t *mddev, int number) 3791 { 3792 raid5_conf_t *conf = mddev->private; 3793 int err = 0; 3794 mdk_rdev_t *rdev; 3795 struct disk_info *p = conf->disks + number; 3796 3797 print_raid5_conf(conf); 3798 rdev = p->rdev; 3799 if (rdev) { 3800 if (test_bit(In_sync, &rdev->flags) || 3801 atomic_read(&rdev->nr_pending)) { 3802 err = -EBUSY; 3803 goto abort; 3804 } 3805 p->rdev = NULL; 3806 synchronize_rcu(); 3807 if (atomic_read(&rdev->nr_pending)) { 3808 /* lost the race, try later */ 3809 err = -EBUSY; 3810 p->rdev = rdev; 3811 } 3812 } 3813 abort: 3814 3815 print_raid5_conf(conf); 3816 return err; 3817 } 3818 3819 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 3820 { 3821 raid5_conf_t *conf = mddev->private; 3822 int found = 0; 3823 int disk; 3824 struct disk_info *p; 3825 3826 if (mddev->degraded > conf->max_degraded) 3827 /* no point adding a device */ 3828 return 0; 3829 3830 /* 3831 * find the disk ... but prefer rdev->saved_raid_disk 3832 * if possible. 3833 */ 3834 if (rdev->saved_raid_disk >= 0 && 3835 conf->disks[rdev->saved_raid_disk].rdev == NULL) 3836 disk = rdev->saved_raid_disk; 3837 else 3838 disk = 0; 3839 for ( ; disk < conf->raid_disks; disk++) 3840 if ((p=conf->disks + disk)->rdev == NULL) { 3841 clear_bit(In_sync, &rdev->flags); 3842 rdev->raid_disk = disk; 3843 found = 1; 3844 if (rdev->saved_raid_disk != disk) 3845 conf->fullsync = 1; 3846 rcu_assign_pointer(p->rdev, rdev); 3847 break; 3848 } 3849 print_raid5_conf(conf); 3850 return found; 3851 } 3852 3853 static int raid5_resize(mddev_t *mddev, sector_t sectors) 3854 { 3855 /* no resync is happening, and there is enough space 3856 * on all devices, so we can resize. 3857 * We need to make sure resync covers any new space. 3858 * If the array is shrinking we should possibly wait until 3859 * any io in the removed space completes, but it hardly seems 3860 * worth it. 3861 */ 3862 raid5_conf_t *conf = mddev_to_conf(mddev); 3863 3864 sectors &= ~((sector_t)mddev->chunk_size/512 - 1); 3865 mddev->array_size = (sectors * (mddev->raid_disks-conf->max_degraded))>>1; 3866 set_capacity(mddev->gendisk, mddev->array_size << 1); 3867 mddev->changed = 1; 3868 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) { 3869 mddev->recovery_cp = mddev->size << 1; 3870 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 3871 } 3872 mddev->size = sectors /2; 3873 mddev->resync_max_sectors = sectors; 3874 return 0; 3875 } 3876 3877 #ifdef CONFIG_MD_RAID5_RESHAPE 3878 static int raid5_check_reshape(mddev_t *mddev) 3879 { 3880 raid5_conf_t *conf = mddev_to_conf(mddev); 3881 int err; 3882 3883 if (mddev->delta_disks < 0 || 3884 mddev->new_level != mddev->level) 3885 return -EINVAL; /* Cannot shrink array or change level yet */ 3886 if (mddev->delta_disks == 0) 3887 return 0; /* nothing to do */ 3888 3889 /* Can only proceed if there are plenty of stripe_heads. 3890 * We need a minimum of one full stripe,, and for sensible progress 3891 * it is best to have about 4 times that. 3892 * If we require 4 times, then the default 256 4K stripe_heads will 3893 * allow for chunk sizes up to 256K, which is probably OK. 3894 * If the chunk size is greater, user-space should request more 3895 * stripe_heads first. 3896 */ 3897 if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes || 3898 (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) { 3899 printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n", 3900 (mddev->chunk_size / STRIPE_SIZE)*4); 3901 return -ENOSPC; 3902 } 3903 3904 err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks); 3905 if (err) 3906 return err; 3907 3908 if (mddev->degraded > conf->max_degraded) 3909 return -EINVAL; 3910 /* looks like we might be able to manage this */ 3911 return 0; 3912 } 3913 3914 static int raid5_start_reshape(mddev_t *mddev) 3915 { 3916 raid5_conf_t *conf = mddev_to_conf(mddev); 3917 mdk_rdev_t *rdev; 3918 struct list_head *rtmp; 3919 int spares = 0; 3920 int added_devices = 0; 3921 unsigned long flags; 3922 3923 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 3924 return -EBUSY; 3925 3926 ITERATE_RDEV(mddev, rdev, rtmp) 3927 if (rdev->raid_disk < 0 && 3928 !test_bit(Faulty, &rdev->flags)) 3929 spares++; 3930 3931 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded) 3932 /* Not enough devices even to make a degraded array 3933 * of that size 3934 */ 3935 return -EINVAL; 3936 3937 atomic_set(&conf->reshape_stripes, 0); 3938 spin_lock_irq(&conf->device_lock); 3939 conf->previous_raid_disks = conf->raid_disks; 3940 conf->raid_disks += mddev->delta_disks; 3941 conf->expand_progress = 0; 3942 conf->expand_lo = 0; 3943 spin_unlock_irq(&conf->device_lock); 3944 3945 /* Add some new drives, as many as will fit. 3946 * We know there are enough to make the newly sized array work. 3947 */ 3948 ITERATE_RDEV(mddev, rdev, rtmp) 3949 if (rdev->raid_disk < 0 && 3950 !test_bit(Faulty, &rdev->flags)) { 3951 if (raid5_add_disk(mddev, rdev)) { 3952 char nm[20]; 3953 set_bit(In_sync, &rdev->flags); 3954 added_devices++; 3955 rdev->recovery_offset = 0; 3956 sprintf(nm, "rd%d", rdev->raid_disk); 3957 if (sysfs_create_link(&mddev->kobj, 3958 &rdev->kobj, nm)) 3959 printk(KERN_WARNING 3960 "raid5: failed to create " 3961 " link %s for %s\n", 3962 nm, mdname(mddev)); 3963 } else 3964 break; 3965 } 3966 3967 spin_lock_irqsave(&conf->device_lock, flags); 3968 mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices; 3969 spin_unlock_irqrestore(&conf->device_lock, flags); 3970 mddev->raid_disks = conf->raid_disks; 3971 mddev->reshape_position = 0; 3972 set_bit(MD_CHANGE_DEVS, &mddev->flags); 3973 3974 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 3975 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 3976 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 3977 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 3978 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 3979 "%s_reshape"); 3980 if (!mddev->sync_thread) { 3981 mddev->recovery = 0; 3982 spin_lock_irq(&conf->device_lock); 3983 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; 3984 conf->expand_progress = MaxSector; 3985 spin_unlock_irq(&conf->device_lock); 3986 return -EAGAIN; 3987 } 3988 md_wakeup_thread(mddev->sync_thread); 3989 md_new_event(mddev); 3990 return 0; 3991 } 3992 #endif 3993 3994 static void end_reshape(raid5_conf_t *conf) 3995 { 3996 struct block_device *bdev; 3997 3998 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) { 3999 conf->mddev->array_size = conf->mddev->size * 4000 (conf->raid_disks - conf->max_degraded); 4001 set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1); 4002 conf->mddev->changed = 1; 4003 4004 bdev = bdget_disk(conf->mddev->gendisk, 0); 4005 if (bdev) { 4006 mutex_lock(&bdev->bd_inode->i_mutex); 4007 i_size_write(bdev->bd_inode, (loff_t)conf->mddev->array_size << 10); 4008 mutex_unlock(&bdev->bd_inode->i_mutex); 4009 bdput(bdev); 4010 } 4011 spin_lock_irq(&conf->device_lock); 4012 conf->expand_progress = MaxSector; 4013 spin_unlock_irq(&conf->device_lock); 4014 conf->mddev->reshape_position = MaxSector; 4015 4016 /* read-ahead size must cover two whole stripes, which is 4017 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 4018 */ 4019 { 4020 int data_disks = conf->previous_raid_disks - conf->max_degraded; 4021 int stripe = data_disks * 4022 (conf->mddev->chunk_size / PAGE_SIZE); 4023 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 4024 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 4025 } 4026 } 4027 } 4028 4029 static void raid5_quiesce(mddev_t *mddev, int state) 4030 { 4031 raid5_conf_t *conf = mddev_to_conf(mddev); 4032 4033 switch(state) { 4034 case 2: /* resume for a suspend */ 4035 wake_up(&conf->wait_for_overlap); 4036 break; 4037 4038 case 1: /* stop all writes */ 4039 spin_lock_irq(&conf->device_lock); 4040 conf->quiesce = 1; 4041 wait_event_lock_irq(conf->wait_for_stripe, 4042 atomic_read(&conf->active_stripes) == 0 && 4043 atomic_read(&conf->active_aligned_reads) == 0, 4044 conf->device_lock, /* nothing */); 4045 spin_unlock_irq(&conf->device_lock); 4046 break; 4047 4048 case 0: /* re-enable writes */ 4049 spin_lock_irq(&conf->device_lock); 4050 conf->quiesce = 0; 4051 wake_up(&conf->wait_for_stripe); 4052 wake_up(&conf->wait_for_overlap); 4053 spin_unlock_irq(&conf->device_lock); 4054 break; 4055 } 4056 } 4057 4058 static struct mdk_personality raid6_personality = 4059 { 4060 .name = "raid6", 4061 .level = 6, 4062 .owner = THIS_MODULE, 4063 .make_request = make_request, 4064 .run = run, 4065 .stop = stop, 4066 .status = status, 4067 .error_handler = error, 4068 .hot_add_disk = raid5_add_disk, 4069 .hot_remove_disk= raid5_remove_disk, 4070 .spare_active = raid5_spare_active, 4071 .sync_request = sync_request, 4072 .resize = raid5_resize, 4073 #ifdef CONFIG_MD_RAID5_RESHAPE 4074 .check_reshape = raid5_check_reshape, 4075 .start_reshape = raid5_start_reshape, 4076 #endif 4077 .quiesce = raid5_quiesce, 4078 }; 4079 static struct mdk_personality raid5_personality = 4080 { 4081 .name = "raid5", 4082 .level = 5, 4083 .owner = THIS_MODULE, 4084 .make_request = make_request, 4085 .run = run, 4086 .stop = stop, 4087 .status = status, 4088 .error_handler = error, 4089 .hot_add_disk = raid5_add_disk, 4090 .hot_remove_disk= raid5_remove_disk, 4091 .spare_active = raid5_spare_active, 4092 .sync_request = sync_request, 4093 .resize = raid5_resize, 4094 #ifdef CONFIG_MD_RAID5_RESHAPE 4095 .check_reshape = raid5_check_reshape, 4096 .start_reshape = raid5_start_reshape, 4097 #endif 4098 .quiesce = raid5_quiesce, 4099 }; 4100 4101 static struct mdk_personality raid4_personality = 4102 { 4103 .name = "raid4", 4104 .level = 4, 4105 .owner = THIS_MODULE, 4106 .make_request = make_request, 4107 .run = run, 4108 .stop = stop, 4109 .status = status, 4110 .error_handler = error, 4111 .hot_add_disk = raid5_add_disk, 4112 .hot_remove_disk= raid5_remove_disk, 4113 .spare_active = raid5_spare_active, 4114 .sync_request = sync_request, 4115 .resize = raid5_resize, 4116 #ifdef CONFIG_MD_RAID5_RESHAPE 4117 .check_reshape = raid5_check_reshape, 4118 .start_reshape = raid5_start_reshape, 4119 #endif 4120 .quiesce = raid5_quiesce, 4121 }; 4122 4123 static int __init raid5_init(void) 4124 { 4125 int e; 4126 4127 e = raid6_select_algo(); 4128 if ( e ) 4129 return e; 4130 register_md_personality(&raid6_personality); 4131 register_md_personality(&raid5_personality); 4132 register_md_personality(&raid4_personality); 4133 return 0; 4134 } 4135 4136 static void raid5_exit(void) 4137 { 4138 unregister_md_personality(&raid6_personality); 4139 unregister_md_personality(&raid5_personality); 4140 unregister_md_personality(&raid4_personality); 4141 } 4142 4143 module_init(raid5_init); 4144 module_exit(raid5_exit); 4145 MODULE_LICENSE("GPL"); 4146 MODULE_ALIAS("md-personality-4"); /* RAID5 */ 4147 MODULE_ALIAS("md-raid5"); 4148 MODULE_ALIAS("md-raid4"); 4149 MODULE_ALIAS("md-level-5"); 4150 MODULE_ALIAS("md-level-4"); 4151 MODULE_ALIAS("md-personality-8"); /* RAID6 */ 4152 MODULE_ALIAS("md-raid6"); 4153 MODULE_ALIAS("md-level-6"); 4154 4155 /* This used to be two separate modules, they were: */ 4156 MODULE_ALIAS("raid5"); 4157 MODULE_ALIAS("raid6"); 4158