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 #include <linux/async_tx.h> 56 57 /* 58 * Stripe cache 59 */ 60 61 #define NR_STRIPES 256 62 #define STRIPE_SIZE PAGE_SIZE 63 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 64 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 65 #define IO_THRESHOLD 1 66 #define BYPASS_THRESHOLD 1 67 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) 68 #define HASH_MASK (NR_HASH - 1) 69 70 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])) 71 72 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 73 * order without overlap. There may be several bio's per stripe+device, and 74 * a bio could span several devices. 75 * When walking this list for a particular stripe+device, we must never proceed 76 * beyond a bio that extends past this device, as the next bio might no longer 77 * be valid. 78 * This macro is used to determine the 'next' bio in the list, given the sector 79 * of the current stripe+device 80 */ 81 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL) 82 /* 83 * The following can be used to debug the driver 84 */ 85 #define RAID5_PARANOIA 1 86 #if RAID5_PARANOIA && defined(CONFIG_SMP) 87 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock) 88 #else 89 # define CHECK_DEVLOCK() 90 #endif 91 92 #ifdef DEBUG 93 #define inline 94 #define __inline__ 95 #endif 96 97 #define printk_rl(args...) ((void) (printk_ratelimit() && printk(args))) 98 99 #if !RAID6_USE_EMPTY_ZERO_PAGE 100 /* In .bss so it's zeroed */ 101 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); 102 #endif 103 104 static inline int raid6_next_disk(int disk, int raid_disks) 105 { 106 disk++; 107 return (disk < raid_disks) ? disk : 0; 108 } 109 110 static void return_io(struct bio *return_bi) 111 { 112 struct bio *bi = return_bi; 113 while (bi) { 114 115 return_bi = bi->bi_next; 116 bi->bi_next = NULL; 117 bi->bi_size = 0; 118 bio_endio(bi, 0); 119 bi = return_bi; 120 } 121 } 122 123 static void print_raid5_conf (raid5_conf_t *conf); 124 125 static int stripe_operations_active(struct stripe_head *sh) 126 { 127 return sh->check_state || sh->reconstruct_state || 128 test_bit(STRIPE_BIOFILL_RUN, &sh->state) || 129 test_bit(STRIPE_COMPUTE_RUN, &sh->state); 130 } 131 132 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) 133 { 134 if (atomic_dec_and_test(&sh->count)) { 135 BUG_ON(!list_empty(&sh->lru)); 136 BUG_ON(atomic_read(&conf->active_stripes)==0); 137 if (test_bit(STRIPE_HANDLE, &sh->state)) { 138 if (test_bit(STRIPE_DELAYED, &sh->state)) { 139 list_add_tail(&sh->lru, &conf->delayed_list); 140 blk_plug_device(conf->mddev->queue); 141 } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && 142 sh->bm_seq - conf->seq_write > 0) { 143 list_add_tail(&sh->lru, &conf->bitmap_list); 144 blk_plug_device(conf->mddev->queue); 145 } else { 146 clear_bit(STRIPE_BIT_DELAY, &sh->state); 147 list_add_tail(&sh->lru, &conf->handle_list); 148 } 149 md_wakeup_thread(conf->mddev->thread); 150 } else { 151 BUG_ON(stripe_operations_active(sh)); 152 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 153 atomic_dec(&conf->preread_active_stripes); 154 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 155 md_wakeup_thread(conf->mddev->thread); 156 } 157 atomic_dec(&conf->active_stripes); 158 if (!test_bit(STRIPE_EXPANDING, &sh->state)) { 159 list_add_tail(&sh->lru, &conf->inactive_list); 160 wake_up(&conf->wait_for_stripe); 161 if (conf->retry_read_aligned) 162 md_wakeup_thread(conf->mddev->thread); 163 } 164 } 165 } 166 } 167 static void release_stripe(struct stripe_head *sh) 168 { 169 raid5_conf_t *conf = sh->raid_conf; 170 unsigned long flags; 171 172 spin_lock_irqsave(&conf->device_lock, flags); 173 __release_stripe(conf, sh); 174 spin_unlock_irqrestore(&conf->device_lock, flags); 175 } 176 177 static inline void remove_hash(struct stripe_head *sh) 178 { 179 pr_debug("remove_hash(), stripe %llu\n", 180 (unsigned long long)sh->sector); 181 182 hlist_del_init(&sh->hash); 183 } 184 185 static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) 186 { 187 struct hlist_head *hp = stripe_hash(conf, sh->sector); 188 189 pr_debug("insert_hash(), stripe %llu\n", 190 (unsigned long long)sh->sector); 191 192 CHECK_DEVLOCK(); 193 hlist_add_head(&sh->hash, hp); 194 } 195 196 197 /* find an idle stripe, make sure it is unhashed, and return it. */ 198 static struct stripe_head *get_free_stripe(raid5_conf_t *conf) 199 { 200 struct stripe_head *sh = NULL; 201 struct list_head *first; 202 203 CHECK_DEVLOCK(); 204 if (list_empty(&conf->inactive_list)) 205 goto out; 206 first = conf->inactive_list.next; 207 sh = list_entry(first, struct stripe_head, lru); 208 list_del_init(first); 209 remove_hash(sh); 210 atomic_inc(&conf->active_stripes); 211 out: 212 return sh; 213 } 214 215 static void shrink_buffers(struct stripe_head *sh, int num) 216 { 217 struct page *p; 218 int i; 219 220 for (i=0; i<num ; i++) { 221 p = sh->dev[i].page; 222 if (!p) 223 continue; 224 sh->dev[i].page = NULL; 225 put_page(p); 226 } 227 } 228 229 static int grow_buffers(struct stripe_head *sh, int num) 230 { 231 int i; 232 233 for (i=0; i<num; i++) { 234 struct page *page; 235 236 if (!(page = alloc_page(GFP_KERNEL))) { 237 return 1; 238 } 239 sh->dev[i].page = page; 240 } 241 return 0; 242 } 243 244 static void raid5_build_block (struct stripe_head *sh, int i); 245 246 static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks) 247 { 248 raid5_conf_t *conf = sh->raid_conf; 249 int i; 250 251 BUG_ON(atomic_read(&sh->count) != 0); 252 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); 253 BUG_ON(stripe_operations_active(sh)); 254 255 CHECK_DEVLOCK(); 256 pr_debug("init_stripe called, stripe %llu\n", 257 (unsigned long long)sh->sector); 258 259 remove_hash(sh); 260 261 sh->sector = sector; 262 sh->pd_idx = pd_idx; 263 sh->state = 0; 264 265 sh->disks = disks; 266 267 for (i = sh->disks; i--; ) { 268 struct r5dev *dev = &sh->dev[i]; 269 270 if (dev->toread || dev->read || dev->towrite || dev->written || 271 test_bit(R5_LOCKED, &dev->flags)) { 272 printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n", 273 (unsigned long long)sh->sector, i, dev->toread, 274 dev->read, dev->towrite, dev->written, 275 test_bit(R5_LOCKED, &dev->flags)); 276 BUG(); 277 } 278 dev->flags = 0; 279 raid5_build_block(sh, i); 280 } 281 insert_hash(conf, sh); 282 } 283 284 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks) 285 { 286 struct stripe_head *sh; 287 struct hlist_node *hn; 288 289 CHECK_DEVLOCK(); 290 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector); 291 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash) 292 if (sh->sector == sector && sh->disks == disks) 293 return sh; 294 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector); 295 return NULL; 296 } 297 298 static void unplug_slaves(mddev_t *mddev); 299 static void raid5_unplug_device(struct request_queue *q); 300 301 static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks, 302 int pd_idx, int noblock) 303 { 304 struct stripe_head *sh; 305 306 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector); 307 308 spin_lock_irq(&conf->device_lock); 309 310 do { 311 wait_event_lock_irq(conf->wait_for_stripe, 312 conf->quiesce == 0, 313 conf->device_lock, /* nothing */); 314 sh = __find_stripe(conf, sector, disks); 315 if (!sh) { 316 if (!conf->inactive_blocked) 317 sh = get_free_stripe(conf); 318 if (noblock && sh == NULL) 319 break; 320 if (!sh) { 321 conf->inactive_blocked = 1; 322 wait_event_lock_irq(conf->wait_for_stripe, 323 !list_empty(&conf->inactive_list) && 324 (atomic_read(&conf->active_stripes) 325 < (conf->max_nr_stripes *3/4) 326 || !conf->inactive_blocked), 327 conf->device_lock, 328 raid5_unplug_device(conf->mddev->queue) 329 ); 330 conf->inactive_blocked = 0; 331 } else 332 init_stripe(sh, sector, pd_idx, disks); 333 } else { 334 if (atomic_read(&sh->count)) { 335 BUG_ON(!list_empty(&sh->lru)); 336 } else { 337 if (!test_bit(STRIPE_HANDLE, &sh->state)) 338 atomic_inc(&conf->active_stripes); 339 if (list_empty(&sh->lru) && 340 !test_bit(STRIPE_EXPANDING, &sh->state)) 341 BUG(); 342 list_del_init(&sh->lru); 343 } 344 } 345 } while (sh == NULL); 346 347 if (sh) 348 atomic_inc(&sh->count); 349 350 spin_unlock_irq(&conf->device_lock); 351 return sh; 352 } 353 354 static void 355 raid5_end_read_request(struct bio *bi, int error); 356 static void 357 raid5_end_write_request(struct bio *bi, int error); 358 359 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 360 { 361 raid5_conf_t *conf = sh->raid_conf; 362 int i, disks = sh->disks; 363 364 might_sleep(); 365 366 for (i = disks; i--; ) { 367 int rw; 368 struct bio *bi; 369 mdk_rdev_t *rdev; 370 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 371 rw = WRITE; 372 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 373 rw = READ; 374 else 375 continue; 376 377 bi = &sh->dev[i].req; 378 379 bi->bi_rw = rw; 380 if (rw == WRITE) 381 bi->bi_end_io = raid5_end_write_request; 382 else 383 bi->bi_end_io = raid5_end_read_request; 384 385 rcu_read_lock(); 386 rdev = rcu_dereference(conf->disks[i].rdev); 387 if (rdev && test_bit(Faulty, &rdev->flags)) 388 rdev = NULL; 389 if (rdev) 390 atomic_inc(&rdev->nr_pending); 391 rcu_read_unlock(); 392 393 if (rdev) { 394 if (s->syncing || s->expanding || s->expanded) 395 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 396 397 set_bit(STRIPE_IO_STARTED, &sh->state); 398 399 bi->bi_bdev = rdev->bdev; 400 pr_debug("%s: for %llu schedule op %ld on disc %d\n", 401 __func__, (unsigned long long)sh->sector, 402 bi->bi_rw, i); 403 atomic_inc(&sh->count); 404 bi->bi_sector = sh->sector + rdev->data_offset; 405 bi->bi_flags = 1 << BIO_UPTODATE; 406 bi->bi_vcnt = 1; 407 bi->bi_max_vecs = 1; 408 bi->bi_idx = 0; 409 bi->bi_io_vec = &sh->dev[i].vec; 410 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 411 bi->bi_io_vec[0].bv_offset = 0; 412 bi->bi_size = STRIPE_SIZE; 413 bi->bi_next = NULL; 414 if (rw == WRITE && 415 test_bit(R5_ReWrite, &sh->dev[i].flags)) 416 atomic_add(STRIPE_SECTORS, 417 &rdev->corrected_errors); 418 generic_make_request(bi); 419 } else { 420 if (rw == WRITE) 421 set_bit(STRIPE_DEGRADED, &sh->state); 422 pr_debug("skip op %ld on disc %d for sector %llu\n", 423 bi->bi_rw, i, (unsigned long long)sh->sector); 424 clear_bit(R5_LOCKED, &sh->dev[i].flags); 425 set_bit(STRIPE_HANDLE, &sh->state); 426 } 427 } 428 } 429 430 static struct dma_async_tx_descriptor * 431 async_copy_data(int frombio, struct bio *bio, struct page *page, 432 sector_t sector, struct dma_async_tx_descriptor *tx) 433 { 434 struct bio_vec *bvl; 435 struct page *bio_page; 436 int i; 437 int page_offset; 438 439 if (bio->bi_sector >= sector) 440 page_offset = (signed)(bio->bi_sector - sector) * 512; 441 else 442 page_offset = (signed)(sector - bio->bi_sector) * -512; 443 bio_for_each_segment(bvl, bio, i) { 444 int len = bio_iovec_idx(bio, i)->bv_len; 445 int clen; 446 int b_offset = 0; 447 448 if (page_offset < 0) { 449 b_offset = -page_offset; 450 page_offset += b_offset; 451 len -= b_offset; 452 } 453 454 if (len > 0 && page_offset + len > STRIPE_SIZE) 455 clen = STRIPE_SIZE - page_offset; 456 else 457 clen = len; 458 459 if (clen > 0) { 460 b_offset += bio_iovec_idx(bio, i)->bv_offset; 461 bio_page = bio_iovec_idx(bio, i)->bv_page; 462 if (frombio) 463 tx = async_memcpy(page, bio_page, page_offset, 464 b_offset, clen, 465 ASYNC_TX_DEP_ACK, 466 tx, NULL, NULL); 467 else 468 tx = async_memcpy(bio_page, page, b_offset, 469 page_offset, clen, 470 ASYNC_TX_DEP_ACK, 471 tx, NULL, NULL); 472 } 473 if (clen < len) /* hit end of page */ 474 break; 475 page_offset += len; 476 } 477 478 return tx; 479 } 480 481 static void ops_complete_biofill(void *stripe_head_ref) 482 { 483 struct stripe_head *sh = stripe_head_ref; 484 struct bio *return_bi = NULL; 485 raid5_conf_t *conf = sh->raid_conf; 486 int i; 487 488 pr_debug("%s: stripe %llu\n", __func__, 489 (unsigned long long)sh->sector); 490 491 /* clear completed biofills */ 492 spin_lock_irq(&conf->device_lock); 493 for (i = sh->disks; i--; ) { 494 struct r5dev *dev = &sh->dev[i]; 495 496 /* acknowledge completion of a biofill operation */ 497 /* and check if we need to reply to a read request, 498 * new R5_Wantfill requests are held off until 499 * !STRIPE_BIOFILL_RUN 500 */ 501 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) { 502 struct bio *rbi, *rbi2; 503 504 BUG_ON(!dev->read); 505 rbi = dev->read; 506 dev->read = NULL; 507 while (rbi && rbi->bi_sector < 508 dev->sector + STRIPE_SECTORS) { 509 rbi2 = r5_next_bio(rbi, dev->sector); 510 if (--rbi->bi_phys_segments == 0) { 511 rbi->bi_next = return_bi; 512 return_bi = rbi; 513 } 514 rbi = rbi2; 515 } 516 } 517 } 518 spin_unlock_irq(&conf->device_lock); 519 clear_bit(STRIPE_BIOFILL_RUN, &sh->state); 520 521 return_io(return_bi); 522 523 set_bit(STRIPE_HANDLE, &sh->state); 524 release_stripe(sh); 525 } 526 527 static void ops_run_biofill(struct stripe_head *sh) 528 { 529 struct dma_async_tx_descriptor *tx = NULL; 530 raid5_conf_t *conf = sh->raid_conf; 531 int i; 532 533 pr_debug("%s: stripe %llu\n", __func__, 534 (unsigned long long)sh->sector); 535 536 for (i = sh->disks; i--; ) { 537 struct r5dev *dev = &sh->dev[i]; 538 if (test_bit(R5_Wantfill, &dev->flags)) { 539 struct bio *rbi; 540 spin_lock_irq(&conf->device_lock); 541 dev->read = rbi = dev->toread; 542 dev->toread = NULL; 543 spin_unlock_irq(&conf->device_lock); 544 while (rbi && rbi->bi_sector < 545 dev->sector + STRIPE_SECTORS) { 546 tx = async_copy_data(0, rbi, dev->page, 547 dev->sector, tx); 548 rbi = r5_next_bio(rbi, dev->sector); 549 } 550 } 551 } 552 553 atomic_inc(&sh->count); 554 async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx, 555 ops_complete_biofill, sh); 556 } 557 558 static void ops_complete_compute5(void *stripe_head_ref) 559 { 560 struct stripe_head *sh = stripe_head_ref; 561 int target = sh->ops.target; 562 struct r5dev *tgt = &sh->dev[target]; 563 564 pr_debug("%s: stripe %llu\n", __func__, 565 (unsigned long long)sh->sector); 566 567 set_bit(R5_UPTODATE, &tgt->flags); 568 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 569 clear_bit(R5_Wantcompute, &tgt->flags); 570 clear_bit(STRIPE_COMPUTE_RUN, &sh->state); 571 if (sh->check_state == check_state_compute_run) 572 sh->check_state = check_state_compute_result; 573 set_bit(STRIPE_HANDLE, &sh->state); 574 release_stripe(sh); 575 } 576 577 static struct dma_async_tx_descriptor *ops_run_compute5(struct stripe_head *sh) 578 { 579 /* kernel stack size limits the total number of disks */ 580 int disks = sh->disks; 581 struct page *xor_srcs[disks]; 582 int target = sh->ops.target; 583 struct r5dev *tgt = &sh->dev[target]; 584 struct page *xor_dest = tgt->page; 585 int count = 0; 586 struct dma_async_tx_descriptor *tx; 587 int i; 588 589 pr_debug("%s: stripe %llu block: %d\n", 590 __func__, (unsigned long long)sh->sector, target); 591 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 592 593 for (i = disks; i--; ) 594 if (i != target) 595 xor_srcs[count++] = sh->dev[i].page; 596 597 atomic_inc(&sh->count); 598 599 if (unlikely(count == 1)) 600 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, 601 0, NULL, ops_complete_compute5, sh); 602 else 603 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, 604 ASYNC_TX_XOR_ZERO_DST, NULL, 605 ops_complete_compute5, sh); 606 607 return tx; 608 } 609 610 static void ops_complete_prexor(void *stripe_head_ref) 611 { 612 struct stripe_head *sh = stripe_head_ref; 613 614 pr_debug("%s: stripe %llu\n", __func__, 615 (unsigned long long)sh->sector); 616 } 617 618 static struct dma_async_tx_descriptor * 619 ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) 620 { 621 /* kernel stack size limits the total number of disks */ 622 int disks = sh->disks; 623 struct page *xor_srcs[disks]; 624 int count = 0, pd_idx = sh->pd_idx, i; 625 626 /* existing parity data subtracted */ 627 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 628 629 pr_debug("%s: stripe %llu\n", __func__, 630 (unsigned long long)sh->sector); 631 632 for (i = disks; i--; ) { 633 struct r5dev *dev = &sh->dev[i]; 634 /* Only process blocks that are known to be uptodate */ 635 if (test_bit(R5_Wantdrain, &dev->flags)) 636 xor_srcs[count++] = dev->page; 637 } 638 639 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, 640 ASYNC_TX_DEP_ACK | ASYNC_TX_XOR_DROP_DST, tx, 641 ops_complete_prexor, sh); 642 643 return tx; 644 } 645 646 static struct dma_async_tx_descriptor * 647 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) 648 { 649 int disks = sh->disks; 650 int i; 651 652 pr_debug("%s: stripe %llu\n", __func__, 653 (unsigned long long)sh->sector); 654 655 for (i = disks; i--; ) { 656 struct r5dev *dev = &sh->dev[i]; 657 struct bio *chosen; 658 659 if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) { 660 struct bio *wbi; 661 662 spin_lock(&sh->lock); 663 chosen = dev->towrite; 664 dev->towrite = NULL; 665 BUG_ON(dev->written); 666 wbi = dev->written = chosen; 667 spin_unlock(&sh->lock); 668 669 while (wbi && wbi->bi_sector < 670 dev->sector + STRIPE_SECTORS) { 671 tx = async_copy_data(1, wbi, dev->page, 672 dev->sector, tx); 673 wbi = r5_next_bio(wbi, dev->sector); 674 } 675 } 676 } 677 678 return tx; 679 } 680 681 static void ops_complete_postxor(void *stripe_head_ref) 682 { 683 struct stripe_head *sh = stripe_head_ref; 684 int disks = sh->disks, i, pd_idx = sh->pd_idx; 685 686 pr_debug("%s: stripe %llu\n", __func__, 687 (unsigned long long)sh->sector); 688 689 for (i = disks; i--; ) { 690 struct r5dev *dev = &sh->dev[i]; 691 if (dev->written || i == pd_idx) 692 set_bit(R5_UPTODATE, &dev->flags); 693 } 694 695 if (sh->reconstruct_state == reconstruct_state_drain_run) 696 sh->reconstruct_state = reconstruct_state_drain_result; 697 else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) 698 sh->reconstruct_state = reconstruct_state_prexor_drain_result; 699 else { 700 BUG_ON(sh->reconstruct_state != reconstruct_state_run); 701 sh->reconstruct_state = reconstruct_state_result; 702 } 703 704 set_bit(STRIPE_HANDLE, &sh->state); 705 release_stripe(sh); 706 } 707 708 static void 709 ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) 710 { 711 /* kernel stack size limits the total number of disks */ 712 int disks = sh->disks; 713 struct page *xor_srcs[disks]; 714 715 int count = 0, pd_idx = sh->pd_idx, i; 716 struct page *xor_dest; 717 int prexor = 0; 718 unsigned long flags; 719 720 pr_debug("%s: stripe %llu\n", __func__, 721 (unsigned long long)sh->sector); 722 723 /* check if prexor is active which means only process blocks 724 * that are part of a read-modify-write (written) 725 */ 726 if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) { 727 prexor = 1; 728 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 729 for (i = disks; i--; ) { 730 struct r5dev *dev = &sh->dev[i]; 731 if (dev->written) 732 xor_srcs[count++] = dev->page; 733 } 734 } else { 735 xor_dest = sh->dev[pd_idx].page; 736 for (i = disks; i--; ) { 737 struct r5dev *dev = &sh->dev[i]; 738 if (i != pd_idx) 739 xor_srcs[count++] = dev->page; 740 } 741 } 742 743 /* 1/ if we prexor'd then the dest is reused as a source 744 * 2/ if we did not prexor then we are redoing the parity 745 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST 746 * for the synchronous xor case 747 */ 748 flags = ASYNC_TX_DEP_ACK | ASYNC_TX_ACK | 749 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST); 750 751 atomic_inc(&sh->count); 752 753 if (unlikely(count == 1)) { 754 flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST); 755 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, 756 flags, tx, ops_complete_postxor, sh); 757 } else 758 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, 759 flags, tx, ops_complete_postxor, sh); 760 } 761 762 static void ops_complete_check(void *stripe_head_ref) 763 { 764 struct stripe_head *sh = stripe_head_ref; 765 766 pr_debug("%s: stripe %llu\n", __func__, 767 (unsigned long long)sh->sector); 768 769 sh->check_state = check_state_check_result; 770 set_bit(STRIPE_HANDLE, &sh->state); 771 release_stripe(sh); 772 } 773 774 static void ops_run_check(struct stripe_head *sh) 775 { 776 /* kernel stack size limits the total number of disks */ 777 int disks = sh->disks; 778 struct page *xor_srcs[disks]; 779 struct dma_async_tx_descriptor *tx; 780 781 int count = 0, pd_idx = sh->pd_idx, i; 782 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 783 784 pr_debug("%s: stripe %llu\n", __func__, 785 (unsigned long long)sh->sector); 786 787 for (i = disks; i--; ) { 788 struct r5dev *dev = &sh->dev[i]; 789 if (i != pd_idx) 790 xor_srcs[count++] = dev->page; 791 } 792 793 tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, 794 &sh->ops.zero_sum_result, 0, NULL, NULL, NULL); 795 796 atomic_inc(&sh->count); 797 tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx, 798 ops_complete_check, sh); 799 } 800 801 static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request) 802 { 803 int overlap_clear = 0, i, disks = sh->disks; 804 struct dma_async_tx_descriptor *tx = NULL; 805 806 if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) { 807 ops_run_biofill(sh); 808 overlap_clear++; 809 } 810 811 if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) { 812 tx = ops_run_compute5(sh); 813 /* terminate the chain if postxor is not set to be run */ 814 if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request)) 815 async_tx_ack(tx); 816 } 817 818 if (test_bit(STRIPE_OP_PREXOR, &ops_request)) 819 tx = ops_run_prexor(sh, tx); 820 821 if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) { 822 tx = ops_run_biodrain(sh, tx); 823 overlap_clear++; 824 } 825 826 if (test_bit(STRIPE_OP_POSTXOR, &ops_request)) 827 ops_run_postxor(sh, tx); 828 829 if (test_bit(STRIPE_OP_CHECK, &ops_request)) 830 ops_run_check(sh); 831 832 if (overlap_clear) 833 for (i = disks; i--; ) { 834 struct r5dev *dev = &sh->dev[i]; 835 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 836 wake_up(&sh->raid_conf->wait_for_overlap); 837 } 838 } 839 840 static int grow_one_stripe(raid5_conf_t *conf) 841 { 842 struct stripe_head *sh; 843 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); 844 if (!sh) 845 return 0; 846 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev)); 847 sh->raid_conf = conf; 848 spin_lock_init(&sh->lock); 849 850 if (grow_buffers(sh, conf->raid_disks)) { 851 shrink_buffers(sh, conf->raid_disks); 852 kmem_cache_free(conf->slab_cache, sh); 853 return 0; 854 } 855 sh->disks = conf->raid_disks; 856 /* we just created an active stripe so... */ 857 atomic_set(&sh->count, 1); 858 atomic_inc(&conf->active_stripes); 859 INIT_LIST_HEAD(&sh->lru); 860 release_stripe(sh); 861 return 1; 862 } 863 864 static int grow_stripes(raid5_conf_t *conf, int num) 865 { 866 struct kmem_cache *sc; 867 int devs = conf->raid_disks; 868 869 sprintf(conf->cache_name[0], "raid5-%s", mdname(conf->mddev)); 870 sprintf(conf->cache_name[1], "raid5-%s-alt", mdname(conf->mddev)); 871 conf->active_name = 0; 872 sc = kmem_cache_create(conf->cache_name[conf->active_name], 873 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 874 0, 0, NULL); 875 if (!sc) 876 return 1; 877 conf->slab_cache = sc; 878 conf->pool_size = devs; 879 while (num--) 880 if (!grow_one_stripe(conf)) 881 return 1; 882 return 0; 883 } 884 885 #ifdef CONFIG_MD_RAID5_RESHAPE 886 static int resize_stripes(raid5_conf_t *conf, int newsize) 887 { 888 /* Make all the stripes able to hold 'newsize' devices. 889 * New slots in each stripe get 'page' set to a new page. 890 * 891 * This happens in stages: 892 * 1/ create a new kmem_cache and allocate the required number of 893 * stripe_heads. 894 * 2/ gather all the old stripe_heads and tranfer the pages across 895 * to the new stripe_heads. This will have the side effect of 896 * freezing the array as once all stripe_heads have been collected, 897 * no IO will be possible. Old stripe heads are freed once their 898 * pages have been transferred over, and the old kmem_cache is 899 * freed when all stripes are done. 900 * 3/ reallocate conf->disks to be suitable bigger. If this fails, 901 * we simple return a failre status - no need to clean anything up. 902 * 4/ allocate new pages for the new slots in the new stripe_heads. 903 * If this fails, we don't bother trying the shrink the 904 * stripe_heads down again, we just leave them as they are. 905 * As each stripe_head is processed the new one is released into 906 * active service. 907 * 908 * Once step2 is started, we cannot afford to wait for a write, 909 * so we use GFP_NOIO allocations. 910 */ 911 struct stripe_head *osh, *nsh; 912 LIST_HEAD(newstripes); 913 struct disk_info *ndisks; 914 int err; 915 struct kmem_cache *sc; 916 int i; 917 918 if (newsize <= conf->pool_size) 919 return 0; /* never bother to shrink */ 920 921 err = md_allow_write(conf->mddev); 922 if (err) 923 return err; 924 925 /* Step 1 */ 926 sc = kmem_cache_create(conf->cache_name[1-conf->active_name], 927 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev), 928 0, 0, NULL); 929 if (!sc) 930 return -ENOMEM; 931 932 for (i = conf->max_nr_stripes; i; i--) { 933 nsh = kmem_cache_alloc(sc, GFP_KERNEL); 934 if (!nsh) 935 break; 936 937 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev)); 938 939 nsh->raid_conf = conf; 940 spin_lock_init(&nsh->lock); 941 942 list_add(&nsh->lru, &newstripes); 943 } 944 if (i) { 945 /* didn't get enough, give up */ 946 while (!list_empty(&newstripes)) { 947 nsh = list_entry(newstripes.next, struct stripe_head, lru); 948 list_del(&nsh->lru); 949 kmem_cache_free(sc, nsh); 950 } 951 kmem_cache_destroy(sc); 952 return -ENOMEM; 953 } 954 /* Step 2 - Must use GFP_NOIO now. 955 * OK, we have enough stripes, start collecting inactive 956 * stripes and copying them over 957 */ 958 list_for_each_entry(nsh, &newstripes, lru) { 959 spin_lock_irq(&conf->device_lock); 960 wait_event_lock_irq(conf->wait_for_stripe, 961 !list_empty(&conf->inactive_list), 962 conf->device_lock, 963 unplug_slaves(conf->mddev) 964 ); 965 osh = get_free_stripe(conf); 966 spin_unlock_irq(&conf->device_lock); 967 atomic_set(&nsh->count, 1); 968 for(i=0; i<conf->pool_size; i++) 969 nsh->dev[i].page = osh->dev[i].page; 970 for( ; i<newsize; i++) 971 nsh->dev[i].page = NULL; 972 kmem_cache_free(conf->slab_cache, osh); 973 } 974 kmem_cache_destroy(conf->slab_cache); 975 976 /* Step 3. 977 * At this point, we are holding all the stripes so the array 978 * is completely stalled, so now is a good time to resize 979 * conf->disks. 980 */ 981 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO); 982 if (ndisks) { 983 for (i=0; i<conf->raid_disks; i++) 984 ndisks[i] = conf->disks[i]; 985 kfree(conf->disks); 986 conf->disks = ndisks; 987 } else 988 err = -ENOMEM; 989 990 /* Step 4, return new stripes to service */ 991 while(!list_empty(&newstripes)) { 992 nsh = list_entry(newstripes.next, struct stripe_head, lru); 993 list_del_init(&nsh->lru); 994 for (i=conf->raid_disks; i < newsize; i++) 995 if (nsh->dev[i].page == NULL) { 996 struct page *p = alloc_page(GFP_NOIO); 997 nsh->dev[i].page = p; 998 if (!p) 999 err = -ENOMEM; 1000 } 1001 release_stripe(nsh); 1002 } 1003 /* critical section pass, GFP_NOIO no longer needed */ 1004 1005 conf->slab_cache = sc; 1006 conf->active_name = 1-conf->active_name; 1007 conf->pool_size = newsize; 1008 return err; 1009 } 1010 #endif 1011 1012 static int drop_one_stripe(raid5_conf_t *conf) 1013 { 1014 struct stripe_head *sh; 1015 1016 spin_lock_irq(&conf->device_lock); 1017 sh = get_free_stripe(conf); 1018 spin_unlock_irq(&conf->device_lock); 1019 if (!sh) 1020 return 0; 1021 BUG_ON(atomic_read(&sh->count)); 1022 shrink_buffers(sh, conf->pool_size); 1023 kmem_cache_free(conf->slab_cache, sh); 1024 atomic_dec(&conf->active_stripes); 1025 return 1; 1026 } 1027 1028 static void shrink_stripes(raid5_conf_t *conf) 1029 { 1030 while (drop_one_stripe(conf)) 1031 ; 1032 1033 if (conf->slab_cache) 1034 kmem_cache_destroy(conf->slab_cache); 1035 conf->slab_cache = NULL; 1036 } 1037 1038 static void raid5_end_read_request(struct bio * bi, int error) 1039 { 1040 struct stripe_head *sh = bi->bi_private; 1041 raid5_conf_t *conf = sh->raid_conf; 1042 int disks = sh->disks, i; 1043 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 1044 char b[BDEVNAME_SIZE]; 1045 mdk_rdev_t *rdev; 1046 1047 1048 for (i=0 ; i<disks; i++) 1049 if (bi == &sh->dev[i].req) 1050 break; 1051 1052 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n", 1053 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 1054 uptodate); 1055 if (i == disks) { 1056 BUG(); 1057 return; 1058 } 1059 1060 if (uptodate) { 1061 set_bit(R5_UPTODATE, &sh->dev[i].flags); 1062 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1063 rdev = conf->disks[i].rdev; 1064 printk_rl(KERN_INFO "raid5:%s: read error corrected" 1065 " (%lu sectors at %llu on %s)\n", 1066 mdname(conf->mddev), STRIPE_SECTORS, 1067 (unsigned long long)(sh->sector 1068 + rdev->data_offset), 1069 bdevname(rdev->bdev, b)); 1070 clear_bit(R5_ReadError, &sh->dev[i].flags); 1071 clear_bit(R5_ReWrite, &sh->dev[i].flags); 1072 } 1073 if (atomic_read(&conf->disks[i].rdev->read_errors)) 1074 atomic_set(&conf->disks[i].rdev->read_errors, 0); 1075 } else { 1076 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b); 1077 int retry = 0; 1078 rdev = conf->disks[i].rdev; 1079 1080 clear_bit(R5_UPTODATE, &sh->dev[i].flags); 1081 atomic_inc(&rdev->read_errors); 1082 if (conf->mddev->degraded) 1083 printk_rl(KERN_WARNING 1084 "raid5:%s: read error not correctable " 1085 "(sector %llu on %s).\n", 1086 mdname(conf->mddev), 1087 (unsigned long long)(sh->sector 1088 + rdev->data_offset), 1089 bdn); 1090 else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) 1091 /* Oh, no!!! */ 1092 printk_rl(KERN_WARNING 1093 "raid5:%s: read error NOT corrected!! " 1094 "(sector %llu on %s).\n", 1095 mdname(conf->mddev), 1096 (unsigned long long)(sh->sector 1097 + rdev->data_offset), 1098 bdn); 1099 else if (atomic_read(&rdev->read_errors) 1100 > conf->max_nr_stripes) 1101 printk(KERN_WARNING 1102 "raid5:%s: Too many read errors, failing device %s.\n", 1103 mdname(conf->mddev), bdn); 1104 else 1105 retry = 1; 1106 if (retry) 1107 set_bit(R5_ReadError, &sh->dev[i].flags); 1108 else { 1109 clear_bit(R5_ReadError, &sh->dev[i].flags); 1110 clear_bit(R5_ReWrite, &sh->dev[i].flags); 1111 md_error(conf->mddev, rdev); 1112 } 1113 } 1114 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 1115 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1116 set_bit(STRIPE_HANDLE, &sh->state); 1117 release_stripe(sh); 1118 } 1119 1120 static void raid5_end_write_request (struct bio *bi, int error) 1121 { 1122 struct stripe_head *sh = bi->bi_private; 1123 raid5_conf_t *conf = sh->raid_conf; 1124 int disks = sh->disks, i; 1125 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 1126 1127 for (i=0 ; i<disks; i++) 1128 if (bi == &sh->dev[i].req) 1129 break; 1130 1131 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n", 1132 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 1133 uptodate); 1134 if (i == disks) { 1135 BUG(); 1136 return; 1137 } 1138 1139 if (!uptodate) 1140 md_error(conf->mddev, conf->disks[i].rdev); 1141 1142 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 1143 1144 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1145 set_bit(STRIPE_HANDLE, &sh->state); 1146 release_stripe(sh); 1147 } 1148 1149 1150 static sector_t compute_blocknr(struct stripe_head *sh, int i); 1151 1152 static void raid5_build_block (struct stripe_head *sh, int i) 1153 { 1154 struct r5dev *dev = &sh->dev[i]; 1155 1156 bio_init(&dev->req); 1157 dev->req.bi_io_vec = &dev->vec; 1158 dev->req.bi_vcnt++; 1159 dev->req.bi_max_vecs++; 1160 dev->vec.bv_page = dev->page; 1161 dev->vec.bv_len = STRIPE_SIZE; 1162 dev->vec.bv_offset = 0; 1163 1164 dev->req.bi_sector = sh->sector; 1165 dev->req.bi_private = sh; 1166 1167 dev->flags = 0; 1168 dev->sector = compute_blocknr(sh, i); 1169 } 1170 1171 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 1172 { 1173 char b[BDEVNAME_SIZE]; 1174 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1175 pr_debug("raid5: error called\n"); 1176 1177 if (!test_bit(Faulty, &rdev->flags)) { 1178 set_bit(MD_CHANGE_DEVS, &mddev->flags); 1179 if (test_and_clear_bit(In_sync, &rdev->flags)) { 1180 unsigned long flags; 1181 spin_lock_irqsave(&conf->device_lock, flags); 1182 mddev->degraded++; 1183 spin_unlock_irqrestore(&conf->device_lock, flags); 1184 /* 1185 * if recovery was running, make sure it aborts. 1186 */ 1187 set_bit(MD_RECOVERY_INTR, &mddev->recovery); 1188 } 1189 set_bit(Faulty, &rdev->flags); 1190 printk (KERN_ALERT 1191 "raid5: Disk failure on %s, disabling device.\n" 1192 "raid5: Operation continuing on %d devices.\n", 1193 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); 1194 } 1195 } 1196 1197 /* 1198 * Input: a 'big' sector number, 1199 * Output: index of the data and parity disk, and the sector # in them. 1200 */ 1201 static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks, 1202 unsigned int data_disks, unsigned int * dd_idx, 1203 unsigned int * pd_idx, raid5_conf_t *conf) 1204 { 1205 long stripe; 1206 unsigned long chunk_number; 1207 unsigned int chunk_offset; 1208 sector_t new_sector; 1209 int sectors_per_chunk = conf->chunk_size >> 9; 1210 1211 /* First compute the information on this sector */ 1212 1213 /* 1214 * Compute the chunk number and the sector offset inside the chunk 1215 */ 1216 chunk_offset = sector_div(r_sector, sectors_per_chunk); 1217 chunk_number = r_sector; 1218 BUG_ON(r_sector != chunk_number); 1219 1220 /* 1221 * Compute the stripe number 1222 */ 1223 stripe = chunk_number / data_disks; 1224 1225 /* 1226 * Compute the data disk and parity disk indexes inside the stripe 1227 */ 1228 *dd_idx = chunk_number % data_disks; 1229 1230 /* 1231 * Select the parity disk based on the user selected algorithm. 1232 */ 1233 switch(conf->level) { 1234 case 4: 1235 *pd_idx = data_disks; 1236 break; 1237 case 5: 1238 switch (conf->algorithm) { 1239 case ALGORITHM_LEFT_ASYMMETRIC: 1240 *pd_idx = data_disks - stripe % raid_disks; 1241 if (*dd_idx >= *pd_idx) 1242 (*dd_idx)++; 1243 break; 1244 case ALGORITHM_RIGHT_ASYMMETRIC: 1245 *pd_idx = stripe % raid_disks; 1246 if (*dd_idx >= *pd_idx) 1247 (*dd_idx)++; 1248 break; 1249 case ALGORITHM_LEFT_SYMMETRIC: 1250 *pd_idx = data_disks - stripe % raid_disks; 1251 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 1252 break; 1253 case ALGORITHM_RIGHT_SYMMETRIC: 1254 *pd_idx = stripe % raid_disks; 1255 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; 1256 break; 1257 default: 1258 printk(KERN_ERR "raid5: unsupported algorithm %d\n", 1259 conf->algorithm); 1260 } 1261 break; 1262 case 6: 1263 1264 /**** FIX THIS ****/ 1265 switch (conf->algorithm) { 1266 case ALGORITHM_LEFT_ASYMMETRIC: 1267 *pd_idx = raid_disks - 1 - (stripe % raid_disks); 1268 if (*pd_idx == raid_disks-1) 1269 (*dd_idx)++; /* Q D D D P */ 1270 else if (*dd_idx >= *pd_idx) 1271 (*dd_idx) += 2; /* D D P Q D */ 1272 break; 1273 case ALGORITHM_RIGHT_ASYMMETRIC: 1274 *pd_idx = stripe % raid_disks; 1275 if (*pd_idx == raid_disks-1) 1276 (*dd_idx)++; /* Q D D D P */ 1277 else if (*dd_idx >= *pd_idx) 1278 (*dd_idx) += 2; /* D D P Q D */ 1279 break; 1280 case ALGORITHM_LEFT_SYMMETRIC: 1281 *pd_idx = raid_disks - 1 - (stripe % raid_disks); 1282 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks; 1283 break; 1284 case ALGORITHM_RIGHT_SYMMETRIC: 1285 *pd_idx = stripe % raid_disks; 1286 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks; 1287 break; 1288 default: 1289 printk (KERN_CRIT "raid6: unsupported algorithm %d\n", 1290 conf->algorithm); 1291 } 1292 break; 1293 } 1294 1295 /* 1296 * Finally, compute the new sector number 1297 */ 1298 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; 1299 return new_sector; 1300 } 1301 1302 1303 static sector_t compute_blocknr(struct stripe_head *sh, int i) 1304 { 1305 raid5_conf_t *conf = sh->raid_conf; 1306 int raid_disks = sh->disks; 1307 int data_disks = raid_disks - conf->max_degraded; 1308 sector_t new_sector = sh->sector, check; 1309 int sectors_per_chunk = conf->chunk_size >> 9; 1310 sector_t stripe; 1311 int chunk_offset; 1312 int chunk_number, dummy1, dummy2, dd_idx = i; 1313 sector_t r_sector; 1314 1315 1316 chunk_offset = sector_div(new_sector, sectors_per_chunk); 1317 stripe = new_sector; 1318 BUG_ON(new_sector != stripe); 1319 1320 if (i == sh->pd_idx) 1321 return 0; 1322 switch(conf->level) { 1323 case 4: break; 1324 case 5: 1325 switch (conf->algorithm) { 1326 case ALGORITHM_LEFT_ASYMMETRIC: 1327 case ALGORITHM_RIGHT_ASYMMETRIC: 1328 if (i > sh->pd_idx) 1329 i--; 1330 break; 1331 case ALGORITHM_LEFT_SYMMETRIC: 1332 case ALGORITHM_RIGHT_SYMMETRIC: 1333 if (i < sh->pd_idx) 1334 i += raid_disks; 1335 i -= (sh->pd_idx + 1); 1336 break; 1337 default: 1338 printk(KERN_ERR "raid5: unsupported algorithm %d\n", 1339 conf->algorithm); 1340 } 1341 break; 1342 case 6: 1343 if (i == raid6_next_disk(sh->pd_idx, raid_disks)) 1344 return 0; /* It is the Q disk */ 1345 switch (conf->algorithm) { 1346 case ALGORITHM_LEFT_ASYMMETRIC: 1347 case ALGORITHM_RIGHT_ASYMMETRIC: 1348 if (sh->pd_idx == raid_disks-1) 1349 i--; /* Q D D D P */ 1350 else if (i > sh->pd_idx) 1351 i -= 2; /* D D P Q D */ 1352 break; 1353 case ALGORITHM_LEFT_SYMMETRIC: 1354 case ALGORITHM_RIGHT_SYMMETRIC: 1355 if (sh->pd_idx == raid_disks-1) 1356 i--; /* Q D D D P */ 1357 else { 1358 /* D D P Q D */ 1359 if (i < sh->pd_idx) 1360 i += raid_disks; 1361 i -= (sh->pd_idx + 2); 1362 } 1363 break; 1364 default: 1365 printk (KERN_CRIT "raid6: unsupported algorithm %d\n", 1366 conf->algorithm); 1367 } 1368 break; 1369 } 1370 1371 chunk_number = stripe * data_disks + i; 1372 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; 1373 1374 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf); 1375 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) { 1376 printk(KERN_ERR "compute_blocknr: map not correct\n"); 1377 return 0; 1378 } 1379 return r_sector; 1380 } 1381 1382 1383 1384 /* 1385 * Copy data between a page in the stripe cache, and one or more bion 1386 * The page could align with the middle of the bio, or there could be 1387 * several bion, each with several bio_vecs, which cover part of the page 1388 * Multiple bion are linked together on bi_next. There may be extras 1389 * at the end of this list. We ignore them. 1390 */ 1391 static void copy_data(int frombio, struct bio *bio, 1392 struct page *page, 1393 sector_t sector) 1394 { 1395 char *pa = page_address(page); 1396 struct bio_vec *bvl; 1397 int i; 1398 int page_offset; 1399 1400 if (bio->bi_sector >= sector) 1401 page_offset = (signed)(bio->bi_sector - sector) * 512; 1402 else 1403 page_offset = (signed)(sector - bio->bi_sector) * -512; 1404 bio_for_each_segment(bvl, bio, i) { 1405 int len = bio_iovec_idx(bio,i)->bv_len; 1406 int clen; 1407 int b_offset = 0; 1408 1409 if (page_offset < 0) { 1410 b_offset = -page_offset; 1411 page_offset += b_offset; 1412 len -= b_offset; 1413 } 1414 1415 if (len > 0 && page_offset + len > STRIPE_SIZE) 1416 clen = STRIPE_SIZE - page_offset; 1417 else clen = len; 1418 1419 if (clen > 0) { 1420 char *ba = __bio_kmap_atomic(bio, i, KM_USER0); 1421 if (frombio) 1422 memcpy(pa+page_offset, ba+b_offset, clen); 1423 else 1424 memcpy(ba+b_offset, pa+page_offset, clen); 1425 __bio_kunmap_atomic(ba, KM_USER0); 1426 } 1427 if (clen < len) /* hit end of page */ 1428 break; 1429 page_offset += len; 1430 } 1431 } 1432 1433 #define check_xor() do { \ 1434 if (count == MAX_XOR_BLOCKS) { \ 1435 xor_blocks(count, STRIPE_SIZE, dest, ptr);\ 1436 count = 0; \ 1437 } \ 1438 } while(0) 1439 1440 static void compute_parity6(struct stripe_head *sh, int method) 1441 { 1442 raid6_conf_t *conf = sh->raid_conf; 1443 int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = sh->disks, count; 1444 struct bio *chosen; 1445 /**** FIX THIS: This could be very bad if disks is close to 256 ****/ 1446 void *ptrs[disks]; 1447 1448 qd_idx = raid6_next_disk(pd_idx, disks); 1449 d0_idx = raid6_next_disk(qd_idx, disks); 1450 1451 pr_debug("compute_parity, stripe %llu, method %d\n", 1452 (unsigned long long)sh->sector, method); 1453 1454 switch(method) { 1455 case READ_MODIFY_WRITE: 1456 BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */ 1457 case RECONSTRUCT_WRITE: 1458 for (i= disks; i-- ;) 1459 if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) { 1460 chosen = sh->dev[i].towrite; 1461 sh->dev[i].towrite = NULL; 1462 1463 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1464 wake_up(&conf->wait_for_overlap); 1465 1466 BUG_ON(sh->dev[i].written); 1467 sh->dev[i].written = chosen; 1468 } 1469 break; 1470 case CHECK_PARITY: 1471 BUG(); /* Not implemented yet */ 1472 } 1473 1474 for (i = disks; i--;) 1475 if (sh->dev[i].written) { 1476 sector_t sector = sh->dev[i].sector; 1477 struct bio *wbi = sh->dev[i].written; 1478 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { 1479 copy_data(1, wbi, sh->dev[i].page, sector); 1480 wbi = r5_next_bio(wbi, sector); 1481 } 1482 1483 set_bit(R5_LOCKED, &sh->dev[i].flags); 1484 set_bit(R5_UPTODATE, &sh->dev[i].flags); 1485 } 1486 1487 // switch(method) { 1488 // case RECONSTRUCT_WRITE: 1489 // case CHECK_PARITY: 1490 // case UPDATE_PARITY: 1491 /* Note that unlike RAID-5, the ordering of the disks matters greatly. */ 1492 /* FIX: Is this ordering of drives even remotely optimal? */ 1493 count = 0; 1494 i = d0_idx; 1495 do { 1496 ptrs[count++] = page_address(sh->dev[i].page); 1497 if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags)) 1498 printk("block %d/%d not uptodate on parity calc\n", i,count); 1499 i = raid6_next_disk(i, disks); 1500 } while ( i != d0_idx ); 1501 // break; 1502 // } 1503 1504 raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs); 1505 1506 switch(method) { 1507 case RECONSTRUCT_WRITE: 1508 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1509 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags); 1510 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 1511 set_bit(R5_LOCKED, &sh->dev[qd_idx].flags); 1512 break; 1513 case UPDATE_PARITY: 1514 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1515 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags); 1516 break; 1517 } 1518 } 1519 1520 1521 /* Compute one missing block */ 1522 static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero) 1523 { 1524 int i, count, disks = sh->disks; 1525 void *ptr[MAX_XOR_BLOCKS], *dest, *p; 1526 int pd_idx = sh->pd_idx; 1527 int qd_idx = raid6_next_disk(pd_idx, disks); 1528 1529 pr_debug("compute_block_1, stripe %llu, idx %d\n", 1530 (unsigned long long)sh->sector, dd_idx); 1531 1532 if ( dd_idx == qd_idx ) { 1533 /* We're actually computing the Q drive */ 1534 compute_parity6(sh, UPDATE_PARITY); 1535 } else { 1536 dest = page_address(sh->dev[dd_idx].page); 1537 if (!nozero) memset(dest, 0, STRIPE_SIZE); 1538 count = 0; 1539 for (i = disks ; i--; ) { 1540 if (i == dd_idx || i == qd_idx) 1541 continue; 1542 p = page_address(sh->dev[i].page); 1543 if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) 1544 ptr[count++] = p; 1545 else 1546 printk("compute_block() %d, stripe %llu, %d" 1547 " not present\n", dd_idx, 1548 (unsigned long long)sh->sector, i); 1549 1550 check_xor(); 1551 } 1552 if (count) 1553 xor_blocks(count, STRIPE_SIZE, dest, ptr); 1554 if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 1555 else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); 1556 } 1557 } 1558 1559 /* Compute two missing blocks */ 1560 static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2) 1561 { 1562 int i, count, disks = sh->disks; 1563 int pd_idx = sh->pd_idx; 1564 int qd_idx = raid6_next_disk(pd_idx, disks); 1565 int d0_idx = raid6_next_disk(qd_idx, disks); 1566 int faila, failb; 1567 1568 /* faila and failb are disk numbers relative to d0_idx */ 1569 /* pd_idx become disks-2 and qd_idx become disks-1 */ 1570 faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx; 1571 failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx; 1572 1573 BUG_ON(faila == failb); 1574 if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; } 1575 1576 pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n", 1577 (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb); 1578 1579 if ( failb == disks-1 ) { 1580 /* Q disk is one of the missing disks */ 1581 if ( faila == disks-2 ) { 1582 /* Missing P+Q, just recompute */ 1583 compute_parity6(sh, UPDATE_PARITY); 1584 return; 1585 } else { 1586 /* We're missing D+Q; recompute D from P */ 1587 compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0); 1588 compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */ 1589 return; 1590 } 1591 } 1592 1593 /* We're missing D+P or D+D; build pointer table */ 1594 { 1595 /**** FIX THIS: This could be very bad if disks is close to 256 ****/ 1596 void *ptrs[disks]; 1597 1598 count = 0; 1599 i = d0_idx; 1600 do { 1601 ptrs[count++] = page_address(sh->dev[i].page); 1602 i = raid6_next_disk(i, disks); 1603 if (i != dd_idx1 && i != dd_idx2 && 1604 !test_bit(R5_UPTODATE, &sh->dev[i].flags)) 1605 printk("compute_2 with missing block %d/%d\n", count, i); 1606 } while ( i != d0_idx ); 1607 1608 if ( failb == disks-2 ) { 1609 /* We're missing D+P. */ 1610 raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs); 1611 } else { 1612 /* We're missing D+D. */ 1613 raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs); 1614 } 1615 1616 /* Both the above update both missing blocks */ 1617 set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags); 1618 set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags); 1619 } 1620 } 1621 1622 static void 1623 schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s, 1624 int rcw, int expand) 1625 { 1626 int i, pd_idx = sh->pd_idx, disks = sh->disks; 1627 1628 if (rcw) { 1629 /* if we are not expanding this is a proper write request, and 1630 * there will be bios with new data to be drained into the 1631 * stripe cache 1632 */ 1633 if (!expand) { 1634 sh->reconstruct_state = reconstruct_state_drain_run; 1635 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); 1636 } else 1637 sh->reconstruct_state = reconstruct_state_run; 1638 1639 set_bit(STRIPE_OP_POSTXOR, &s->ops_request); 1640 1641 for (i = disks; i--; ) { 1642 struct r5dev *dev = &sh->dev[i]; 1643 1644 if (dev->towrite) { 1645 set_bit(R5_LOCKED, &dev->flags); 1646 set_bit(R5_Wantdrain, &dev->flags); 1647 if (!expand) 1648 clear_bit(R5_UPTODATE, &dev->flags); 1649 s->locked++; 1650 } 1651 } 1652 if (s->locked + 1 == disks) 1653 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state)) 1654 atomic_inc(&sh->raid_conf->pending_full_writes); 1655 } else { 1656 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) || 1657 test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags))); 1658 1659 sh->reconstruct_state = reconstruct_state_prexor_drain_run; 1660 set_bit(STRIPE_OP_PREXOR, &s->ops_request); 1661 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); 1662 set_bit(STRIPE_OP_POSTXOR, &s->ops_request); 1663 1664 for (i = disks; i--; ) { 1665 struct r5dev *dev = &sh->dev[i]; 1666 if (i == pd_idx) 1667 continue; 1668 1669 if (dev->towrite && 1670 (test_bit(R5_UPTODATE, &dev->flags) || 1671 test_bit(R5_Wantcompute, &dev->flags))) { 1672 set_bit(R5_Wantdrain, &dev->flags); 1673 set_bit(R5_LOCKED, &dev->flags); 1674 clear_bit(R5_UPTODATE, &dev->flags); 1675 s->locked++; 1676 } 1677 } 1678 } 1679 1680 /* keep the parity disk locked while asynchronous operations 1681 * are in flight 1682 */ 1683 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 1684 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 1685 s->locked++; 1686 1687 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n", 1688 __func__, (unsigned long long)sh->sector, 1689 s->locked, s->ops_request); 1690 } 1691 1692 /* 1693 * Each stripe/dev can have one or more bion attached. 1694 * toread/towrite point to the first in a chain. 1695 * The bi_next chain must be in order. 1696 */ 1697 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) 1698 { 1699 struct bio **bip; 1700 raid5_conf_t *conf = sh->raid_conf; 1701 int firstwrite=0; 1702 1703 pr_debug("adding bh b#%llu to stripe s#%llu\n", 1704 (unsigned long long)bi->bi_sector, 1705 (unsigned long long)sh->sector); 1706 1707 1708 spin_lock(&sh->lock); 1709 spin_lock_irq(&conf->device_lock); 1710 if (forwrite) { 1711 bip = &sh->dev[dd_idx].towrite; 1712 if (*bip == NULL && sh->dev[dd_idx].written == NULL) 1713 firstwrite = 1; 1714 } else 1715 bip = &sh->dev[dd_idx].toread; 1716 while (*bip && (*bip)->bi_sector < bi->bi_sector) { 1717 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) 1718 goto overlap; 1719 bip = & (*bip)->bi_next; 1720 } 1721 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) 1722 goto overlap; 1723 1724 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next); 1725 if (*bip) 1726 bi->bi_next = *bip; 1727 *bip = bi; 1728 bi->bi_phys_segments ++; 1729 spin_unlock_irq(&conf->device_lock); 1730 spin_unlock(&sh->lock); 1731 1732 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n", 1733 (unsigned long long)bi->bi_sector, 1734 (unsigned long long)sh->sector, dd_idx); 1735 1736 if (conf->mddev->bitmap && firstwrite) { 1737 bitmap_startwrite(conf->mddev->bitmap, sh->sector, 1738 STRIPE_SECTORS, 0); 1739 sh->bm_seq = conf->seq_flush+1; 1740 set_bit(STRIPE_BIT_DELAY, &sh->state); 1741 } 1742 1743 if (forwrite) { 1744 /* check if page is covered */ 1745 sector_t sector = sh->dev[dd_idx].sector; 1746 for (bi=sh->dev[dd_idx].towrite; 1747 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && 1748 bi && bi->bi_sector <= sector; 1749 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { 1750 if (bi->bi_sector + (bi->bi_size>>9) >= sector) 1751 sector = bi->bi_sector + (bi->bi_size>>9); 1752 } 1753 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) 1754 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); 1755 } 1756 return 1; 1757 1758 overlap: 1759 set_bit(R5_Overlap, &sh->dev[dd_idx].flags); 1760 spin_unlock_irq(&conf->device_lock); 1761 spin_unlock(&sh->lock); 1762 return 0; 1763 } 1764 1765 static void end_reshape(raid5_conf_t *conf); 1766 1767 static int page_is_zero(struct page *p) 1768 { 1769 char *a = page_address(p); 1770 return ((*(u32*)a) == 0 && 1771 memcmp(a, a+4, STRIPE_SIZE-4)==0); 1772 } 1773 1774 static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks) 1775 { 1776 int sectors_per_chunk = conf->chunk_size >> 9; 1777 int pd_idx, dd_idx; 1778 int chunk_offset = sector_div(stripe, sectors_per_chunk); 1779 1780 raid5_compute_sector(stripe * (disks - conf->max_degraded) 1781 *sectors_per_chunk + chunk_offset, 1782 disks, disks - conf->max_degraded, 1783 &dd_idx, &pd_idx, conf); 1784 return pd_idx; 1785 } 1786 1787 static void 1788 handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, 1789 struct stripe_head_state *s, int disks, 1790 struct bio **return_bi) 1791 { 1792 int i; 1793 for (i = disks; i--; ) { 1794 struct bio *bi; 1795 int bitmap_end = 0; 1796 1797 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1798 mdk_rdev_t *rdev; 1799 rcu_read_lock(); 1800 rdev = rcu_dereference(conf->disks[i].rdev); 1801 if (rdev && test_bit(In_sync, &rdev->flags)) 1802 /* multiple read failures in one stripe */ 1803 md_error(conf->mddev, rdev); 1804 rcu_read_unlock(); 1805 } 1806 spin_lock_irq(&conf->device_lock); 1807 /* fail all writes first */ 1808 bi = sh->dev[i].towrite; 1809 sh->dev[i].towrite = NULL; 1810 if (bi) { 1811 s->to_write--; 1812 bitmap_end = 1; 1813 } 1814 1815 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1816 wake_up(&conf->wait_for_overlap); 1817 1818 while (bi && bi->bi_sector < 1819 sh->dev[i].sector + STRIPE_SECTORS) { 1820 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 1821 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1822 if (--bi->bi_phys_segments == 0) { 1823 md_write_end(conf->mddev); 1824 bi->bi_next = *return_bi; 1825 *return_bi = bi; 1826 } 1827 bi = nextbi; 1828 } 1829 /* and fail all 'written' */ 1830 bi = sh->dev[i].written; 1831 sh->dev[i].written = NULL; 1832 if (bi) bitmap_end = 1; 1833 while (bi && bi->bi_sector < 1834 sh->dev[i].sector + STRIPE_SECTORS) { 1835 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 1836 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1837 if (--bi->bi_phys_segments == 0) { 1838 md_write_end(conf->mddev); 1839 bi->bi_next = *return_bi; 1840 *return_bi = bi; 1841 } 1842 bi = bi2; 1843 } 1844 1845 /* fail any reads if this device is non-operational and 1846 * the data has not reached the cache yet. 1847 */ 1848 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) && 1849 (!test_bit(R5_Insync, &sh->dev[i].flags) || 1850 test_bit(R5_ReadError, &sh->dev[i].flags))) { 1851 bi = sh->dev[i].toread; 1852 sh->dev[i].toread = NULL; 1853 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 1854 wake_up(&conf->wait_for_overlap); 1855 if (bi) s->to_read--; 1856 while (bi && bi->bi_sector < 1857 sh->dev[i].sector + STRIPE_SECTORS) { 1858 struct bio *nextbi = 1859 r5_next_bio(bi, sh->dev[i].sector); 1860 clear_bit(BIO_UPTODATE, &bi->bi_flags); 1861 if (--bi->bi_phys_segments == 0) { 1862 bi->bi_next = *return_bi; 1863 *return_bi = bi; 1864 } 1865 bi = nextbi; 1866 } 1867 } 1868 spin_unlock_irq(&conf->device_lock); 1869 if (bitmap_end) 1870 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 1871 STRIPE_SECTORS, 0, 0); 1872 } 1873 1874 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) 1875 if (atomic_dec_and_test(&conf->pending_full_writes)) 1876 md_wakeup_thread(conf->mddev->thread); 1877 } 1878 1879 /* fetch_block5 - checks the given member device to see if its data needs 1880 * to be read or computed to satisfy a request. 1881 * 1882 * Returns 1 when no more member devices need to be checked, otherwise returns 1883 * 0 to tell the loop in handle_stripe_fill5 to continue 1884 */ 1885 static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s, 1886 int disk_idx, int disks) 1887 { 1888 struct r5dev *dev = &sh->dev[disk_idx]; 1889 struct r5dev *failed_dev = &sh->dev[s->failed_num]; 1890 1891 /* is the data in this block needed, and can we get it? */ 1892 if (!test_bit(R5_LOCKED, &dev->flags) && 1893 !test_bit(R5_UPTODATE, &dev->flags) && 1894 (dev->toread || 1895 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 1896 s->syncing || s->expanding || 1897 (s->failed && 1898 (failed_dev->toread || 1899 (failed_dev->towrite && 1900 !test_bit(R5_OVERWRITE, &failed_dev->flags)))))) { 1901 /* We would like to get this block, possibly by computing it, 1902 * otherwise read it if the backing disk is insync 1903 */ 1904 if ((s->uptodate == disks - 1) && 1905 (s->failed && disk_idx == s->failed_num)) { 1906 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 1907 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 1908 set_bit(R5_Wantcompute, &dev->flags); 1909 sh->ops.target = disk_idx; 1910 s->req_compute = 1; 1911 /* Careful: from this point on 'uptodate' is in the eye 1912 * of raid5_run_ops which services 'compute' operations 1913 * before writes. R5_Wantcompute flags a block that will 1914 * be R5_UPTODATE by the time it is needed for a 1915 * subsequent operation. 1916 */ 1917 s->uptodate++; 1918 return 1; /* uptodate + compute == disks */ 1919 } else if (test_bit(R5_Insync, &dev->flags)) { 1920 set_bit(R5_LOCKED, &dev->flags); 1921 set_bit(R5_Wantread, &dev->flags); 1922 s->locked++; 1923 pr_debug("Reading block %d (sync=%d)\n", disk_idx, 1924 s->syncing); 1925 } 1926 } 1927 1928 return 0; 1929 } 1930 1931 /** 1932 * handle_stripe_fill5 - read or compute data to satisfy pending requests. 1933 */ 1934 static void handle_stripe_fill5(struct stripe_head *sh, 1935 struct stripe_head_state *s, int disks) 1936 { 1937 int i; 1938 1939 /* look for blocks to read/compute, skip this if a compute 1940 * is already in flight, or if the stripe contents are in the 1941 * midst of changing due to a write 1942 */ 1943 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state && 1944 !sh->reconstruct_state) 1945 for (i = disks; i--; ) 1946 if (fetch_block5(sh, s, i, disks)) 1947 break; 1948 set_bit(STRIPE_HANDLE, &sh->state); 1949 } 1950 1951 static void handle_stripe_fill6(struct stripe_head *sh, 1952 struct stripe_head_state *s, struct r6_state *r6s, 1953 int disks) 1954 { 1955 int i; 1956 for (i = disks; i--; ) { 1957 struct r5dev *dev = &sh->dev[i]; 1958 if (!test_bit(R5_LOCKED, &dev->flags) && 1959 !test_bit(R5_UPTODATE, &dev->flags) && 1960 (dev->toread || (dev->towrite && 1961 !test_bit(R5_OVERWRITE, &dev->flags)) || 1962 s->syncing || s->expanding || 1963 (s->failed >= 1 && 1964 (sh->dev[r6s->failed_num[0]].toread || 1965 s->to_write)) || 1966 (s->failed >= 2 && 1967 (sh->dev[r6s->failed_num[1]].toread || 1968 s->to_write)))) { 1969 /* we would like to get this block, possibly 1970 * by computing it, but we might not be able to 1971 */ 1972 if ((s->uptodate == disks - 1) && 1973 (s->failed && (i == r6s->failed_num[0] || 1974 i == r6s->failed_num[1]))) { 1975 pr_debug("Computing stripe %llu block %d\n", 1976 (unsigned long long)sh->sector, i); 1977 compute_block_1(sh, i, 0); 1978 s->uptodate++; 1979 } else if ( s->uptodate == disks-2 && s->failed >= 2 ) { 1980 /* Computing 2-failure is *very* expensive; only 1981 * do it if failed >= 2 1982 */ 1983 int other; 1984 for (other = disks; other--; ) { 1985 if (other == i) 1986 continue; 1987 if (!test_bit(R5_UPTODATE, 1988 &sh->dev[other].flags)) 1989 break; 1990 } 1991 BUG_ON(other < 0); 1992 pr_debug("Computing stripe %llu blocks %d,%d\n", 1993 (unsigned long long)sh->sector, 1994 i, other); 1995 compute_block_2(sh, i, other); 1996 s->uptodate += 2; 1997 } else if (test_bit(R5_Insync, &dev->flags)) { 1998 set_bit(R5_LOCKED, &dev->flags); 1999 set_bit(R5_Wantread, &dev->flags); 2000 s->locked++; 2001 pr_debug("Reading block %d (sync=%d)\n", 2002 i, s->syncing); 2003 } 2004 } 2005 } 2006 set_bit(STRIPE_HANDLE, &sh->state); 2007 } 2008 2009 2010 /* handle_stripe_clean_event 2011 * any written block on an uptodate or failed drive can be returned. 2012 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but 2013 * never LOCKED, so we don't need to test 'failed' directly. 2014 */ 2015 static void handle_stripe_clean_event(raid5_conf_t *conf, 2016 struct stripe_head *sh, int disks, struct bio **return_bi) 2017 { 2018 int i; 2019 struct r5dev *dev; 2020 2021 for (i = disks; i--; ) 2022 if (sh->dev[i].written) { 2023 dev = &sh->dev[i]; 2024 if (!test_bit(R5_LOCKED, &dev->flags) && 2025 test_bit(R5_UPTODATE, &dev->flags)) { 2026 /* We can return any write requests */ 2027 struct bio *wbi, *wbi2; 2028 int bitmap_end = 0; 2029 pr_debug("Return write for disc %d\n", i); 2030 spin_lock_irq(&conf->device_lock); 2031 wbi = dev->written; 2032 dev->written = NULL; 2033 while (wbi && wbi->bi_sector < 2034 dev->sector + STRIPE_SECTORS) { 2035 wbi2 = r5_next_bio(wbi, dev->sector); 2036 if (--wbi->bi_phys_segments == 0) { 2037 md_write_end(conf->mddev); 2038 wbi->bi_next = *return_bi; 2039 *return_bi = wbi; 2040 } 2041 wbi = wbi2; 2042 } 2043 if (dev->towrite == NULL) 2044 bitmap_end = 1; 2045 spin_unlock_irq(&conf->device_lock); 2046 if (bitmap_end) 2047 bitmap_endwrite(conf->mddev->bitmap, 2048 sh->sector, 2049 STRIPE_SECTORS, 2050 !test_bit(STRIPE_DEGRADED, &sh->state), 2051 0); 2052 } 2053 } 2054 2055 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) 2056 if (atomic_dec_and_test(&conf->pending_full_writes)) 2057 md_wakeup_thread(conf->mddev->thread); 2058 } 2059 2060 static void handle_stripe_dirtying5(raid5_conf_t *conf, 2061 struct stripe_head *sh, struct stripe_head_state *s, int disks) 2062 { 2063 int rmw = 0, rcw = 0, i; 2064 for (i = disks; i--; ) { 2065 /* would I have to read this buffer for read_modify_write */ 2066 struct r5dev *dev = &sh->dev[i]; 2067 if ((dev->towrite || i == sh->pd_idx) && 2068 !test_bit(R5_LOCKED, &dev->flags) && 2069 !(test_bit(R5_UPTODATE, &dev->flags) || 2070 test_bit(R5_Wantcompute, &dev->flags))) { 2071 if (test_bit(R5_Insync, &dev->flags)) 2072 rmw++; 2073 else 2074 rmw += 2*disks; /* cannot read it */ 2075 } 2076 /* Would I have to read this buffer for reconstruct_write */ 2077 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 2078 !test_bit(R5_LOCKED, &dev->flags) && 2079 !(test_bit(R5_UPTODATE, &dev->flags) || 2080 test_bit(R5_Wantcompute, &dev->flags))) { 2081 if (test_bit(R5_Insync, &dev->flags)) rcw++; 2082 else 2083 rcw += 2*disks; 2084 } 2085 } 2086 pr_debug("for sector %llu, rmw=%d rcw=%d\n", 2087 (unsigned long long)sh->sector, rmw, rcw); 2088 set_bit(STRIPE_HANDLE, &sh->state); 2089 if (rmw < rcw && rmw > 0) 2090 /* prefer read-modify-write, but need to get some data */ 2091 for (i = disks; i--; ) { 2092 struct r5dev *dev = &sh->dev[i]; 2093 if ((dev->towrite || i == sh->pd_idx) && 2094 !test_bit(R5_LOCKED, &dev->flags) && 2095 !(test_bit(R5_UPTODATE, &dev->flags) || 2096 test_bit(R5_Wantcompute, &dev->flags)) && 2097 test_bit(R5_Insync, &dev->flags)) { 2098 if ( 2099 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2100 pr_debug("Read_old block " 2101 "%d for r-m-w\n", i); 2102 set_bit(R5_LOCKED, &dev->flags); 2103 set_bit(R5_Wantread, &dev->flags); 2104 s->locked++; 2105 } else { 2106 set_bit(STRIPE_DELAYED, &sh->state); 2107 set_bit(STRIPE_HANDLE, &sh->state); 2108 } 2109 } 2110 } 2111 if (rcw <= rmw && rcw > 0) 2112 /* want reconstruct write, but need to get some data */ 2113 for (i = disks; i--; ) { 2114 struct r5dev *dev = &sh->dev[i]; 2115 if (!test_bit(R5_OVERWRITE, &dev->flags) && 2116 i != sh->pd_idx && 2117 !test_bit(R5_LOCKED, &dev->flags) && 2118 !(test_bit(R5_UPTODATE, &dev->flags) || 2119 test_bit(R5_Wantcompute, &dev->flags)) && 2120 test_bit(R5_Insync, &dev->flags)) { 2121 if ( 2122 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2123 pr_debug("Read_old block " 2124 "%d for Reconstruct\n", i); 2125 set_bit(R5_LOCKED, &dev->flags); 2126 set_bit(R5_Wantread, &dev->flags); 2127 s->locked++; 2128 } else { 2129 set_bit(STRIPE_DELAYED, &sh->state); 2130 set_bit(STRIPE_HANDLE, &sh->state); 2131 } 2132 } 2133 } 2134 /* now if nothing is locked, and if we have enough data, 2135 * we can start a write request 2136 */ 2137 /* since handle_stripe can be called at any time we need to handle the 2138 * case where a compute block operation has been submitted and then a 2139 * subsequent call wants to start a write request. raid5_run_ops only 2140 * handles the case where compute block and postxor are requested 2141 * simultaneously. If this is not the case then new writes need to be 2142 * held off until the compute completes. 2143 */ 2144 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) && 2145 (s->locked == 0 && (rcw == 0 || rmw == 0) && 2146 !test_bit(STRIPE_BIT_DELAY, &sh->state))) 2147 schedule_reconstruction5(sh, s, rcw == 0, 0); 2148 } 2149 2150 static void handle_stripe_dirtying6(raid5_conf_t *conf, 2151 struct stripe_head *sh, struct stripe_head_state *s, 2152 struct r6_state *r6s, int disks) 2153 { 2154 int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i; 2155 int qd_idx = r6s->qd_idx; 2156 for (i = disks; i--; ) { 2157 struct r5dev *dev = &sh->dev[i]; 2158 /* Would I have to read this buffer for reconstruct_write */ 2159 if (!test_bit(R5_OVERWRITE, &dev->flags) 2160 && i != pd_idx && i != qd_idx 2161 && (!test_bit(R5_LOCKED, &dev->flags) 2162 ) && 2163 !test_bit(R5_UPTODATE, &dev->flags)) { 2164 if (test_bit(R5_Insync, &dev->flags)) rcw++; 2165 else { 2166 pr_debug("raid6: must_compute: " 2167 "disk %d flags=%#lx\n", i, dev->flags); 2168 must_compute++; 2169 } 2170 } 2171 } 2172 pr_debug("for sector %llu, rcw=%d, must_compute=%d\n", 2173 (unsigned long long)sh->sector, rcw, must_compute); 2174 set_bit(STRIPE_HANDLE, &sh->state); 2175 2176 if (rcw > 0) 2177 /* want reconstruct write, but need to get some data */ 2178 for (i = disks; i--; ) { 2179 struct r5dev *dev = &sh->dev[i]; 2180 if (!test_bit(R5_OVERWRITE, &dev->flags) 2181 && !(s->failed == 0 && (i == pd_idx || i == qd_idx)) 2182 && !test_bit(R5_LOCKED, &dev->flags) && 2183 !test_bit(R5_UPTODATE, &dev->flags) && 2184 test_bit(R5_Insync, &dev->flags)) { 2185 if ( 2186 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2187 pr_debug("Read_old stripe %llu " 2188 "block %d for Reconstruct\n", 2189 (unsigned long long)sh->sector, i); 2190 set_bit(R5_LOCKED, &dev->flags); 2191 set_bit(R5_Wantread, &dev->flags); 2192 s->locked++; 2193 } else { 2194 pr_debug("Request delayed stripe %llu " 2195 "block %d for Reconstruct\n", 2196 (unsigned long long)sh->sector, i); 2197 set_bit(STRIPE_DELAYED, &sh->state); 2198 set_bit(STRIPE_HANDLE, &sh->state); 2199 } 2200 } 2201 } 2202 /* now if nothing is locked, and if we have enough data, we can start a 2203 * write request 2204 */ 2205 if (s->locked == 0 && rcw == 0 && 2206 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 2207 if (must_compute > 0) { 2208 /* We have failed blocks and need to compute them */ 2209 switch (s->failed) { 2210 case 0: 2211 BUG(); 2212 case 1: 2213 compute_block_1(sh, r6s->failed_num[0], 0); 2214 break; 2215 case 2: 2216 compute_block_2(sh, r6s->failed_num[0], 2217 r6s->failed_num[1]); 2218 break; 2219 default: /* This request should have been failed? */ 2220 BUG(); 2221 } 2222 } 2223 2224 pr_debug("Computing parity for stripe %llu\n", 2225 (unsigned long long)sh->sector); 2226 compute_parity6(sh, RECONSTRUCT_WRITE); 2227 /* now every locked buffer is ready to be written */ 2228 for (i = disks; i--; ) 2229 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { 2230 pr_debug("Writing stripe %llu block %d\n", 2231 (unsigned long long)sh->sector, i); 2232 s->locked++; 2233 set_bit(R5_Wantwrite, &sh->dev[i].flags); 2234 } 2235 if (s->locked == disks) 2236 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state)) 2237 atomic_inc(&conf->pending_full_writes); 2238 /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */ 2239 set_bit(STRIPE_INSYNC, &sh->state); 2240 2241 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2242 atomic_dec(&conf->preread_active_stripes); 2243 if (atomic_read(&conf->preread_active_stripes) < 2244 IO_THRESHOLD) 2245 md_wakeup_thread(conf->mddev->thread); 2246 } 2247 } 2248 } 2249 2250 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh, 2251 struct stripe_head_state *s, int disks) 2252 { 2253 struct r5dev *dev = NULL; 2254 2255 set_bit(STRIPE_HANDLE, &sh->state); 2256 2257 switch (sh->check_state) { 2258 case check_state_idle: 2259 /* start a new check operation if there are no failures */ 2260 if (s->failed == 0) { 2261 BUG_ON(s->uptodate != disks); 2262 sh->check_state = check_state_run; 2263 set_bit(STRIPE_OP_CHECK, &s->ops_request); 2264 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags); 2265 s->uptodate--; 2266 break; 2267 } 2268 dev = &sh->dev[s->failed_num]; 2269 /* fall through */ 2270 case check_state_compute_result: 2271 sh->check_state = check_state_idle; 2272 if (!dev) 2273 dev = &sh->dev[sh->pd_idx]; 2274 2275 /* check that a write has not made the stripe insync */ 2276 if (test_bit(STRIPE_INSYNC, &sh->state)) 2277 break; 2278 2279 /* either failed parity check, or recovery is happening */ 2280 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); 2281 BUG_ON(s->uptodate != disks); 2282 2283 set_bit(R5_LOCKED, &dev->flags); 2284 s->locked++; 2285 set_bit(R5_Wantwrite, &dev->flags); 2286 2287 clear_bit(STRIPE_DEGRADED, &sh->state); 2288 set_bit(STRIPE_INSYNC, &sh->state); 2289 break; 2290 case check_state_run: 2291 break; /* we will be called again upon completion */ 2292 case check_state_check_result: 2293 sh->check_state = check_state_idle; 2294 2295 /* if a failure occurred during the check operation, leave 2296 * STRIPE_INSYNC not set and let the stripe be handled again 2297 */ 2298 if (s->failed) 2299 break; 2300 2301 /* handle a successful check operation, if parity is correct 2302 * we are done. Otherwise update the mismatch count and repair 2303 * parity if !MD_RECOVERY_CHECK 2304 */ 2305 if (sh->ops.zero_sum_result == 0) 2306 /* parity is correct (on disc, 2307 * not in buffer any more) 2308 */ 2309 set_bit(STRIPE_INSYNC, &sh->state); 2310 else { 2311 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2312 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2313 /* don't try to repair!! */ 2314 set_bit(STRIPE_INSYNC, &sh->state); 2315 else { 2316 sh->check_state = check_state_compute_run; 2317 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2318 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2319 set_bit(R5_Wantcompute, 2320 &sh->dev[sh->pd_idx].flags); 2321 sh->ops.target = sh->pd_idx; 2322 s->uptodate++; 2323 } 2324 } 2325 break; 2326 case check_state_compute_run: 2327 break; 2328 default: 2329 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n", 2330 __func__, sh->check_state, 2331 (unsigned long long) sh->sector); 2332 BUG(); 2333 } 2334 } 2335 2336 2337 static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh, 2338 struct stripe_head_state *s, 2339 struct r6_state *r6s, struct page *tmp_page, 2340 int disks) 2341 { 2342 int update_p = 0, update_q = 0; 2343 struct r5dev *dev; 2344 int pd_idx = sh->pd_idx; 2345 int qd_idx = r6s->qd_idx; 2346 2347 set_bit(STRIPE_HANDLE, &sh->state); 2348 2349 BUG_ON(s->failed > 2); 2350 BUG_ON(s->uptodate < disks); 2351 /* Want to check and possibly repair P and Q. 2352 * However there could be one 'failed' device, in which 2353 * case we can only check one of them, possibly using the 2354 * other to generate missing data 2355 */ 2356 2357 /* If !tmp_page, we cannot do the calculations, 2358 * but as we have set STRIPE_HANDLE, we will soon be called 2359 * by stripe_handle with a tmp_page - just wait until then. 2360 */ 2361 if (tmp_page) { 2362 if (s->failed == r6s->q_failed) { 2363 /* The only possible failed device holds 'Q', so it 2364 * makes sense to check P (If anything else were failed, 2365 * we would have used P to recreate it). 2366 */ 2367 compute_block_1(sh, pd_idx, 1); 2368 if (!page_is_zero(sh->dev[pd_idx].page)) { 2369 compute_block_1(sh, pd_idx, 0); 2370 update_p = 1; 2371 } 2372 } 2373 if (!r6s->q_failed && s->failed < 2) { 2374 /* q is not failed, and we didn't use it to generate 2375 * anything, so it makes sense to check it 2376 */ 2377 memcpy(page_address(tmp_page), 2378 page_address(sh->dev[qd_idx].page), 2379 STRIPE_SIZE); 2380 compute_parity6(sh, UPDATE_PARITY); 2381 if (memcmp(page_address(tmp_page), 2382 page_address(sh->dev[qd_idx].page), 2383 STRIPE_SIZE) != 0) { 2384 clear_bit(STRIPE_INSYNC, &sh->state); 2385 update_q = 1; 2386 } 2387 } 2388 if (update_p || update_q) { 2389 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2390 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2391 /* don't try to repair!! */ 2392 update_p = update_q = 0; 2393 } 2394 2395 /* now write out any block on a failed drive, 2396 * or P or Q if they need it 2397 */ 2398 2399 if (s->failed == 2) { 2400 dev = &sh->dev[r6s->failed_num[1]]; 2401 s->locked++; 2402 set_bit(R5_LOCKED, &dev->flags); 2403 set_bit(R5_Wantwrite, &dev->flags); 2404 } 2405 if (s->failed >= 1) { 2406 dev = &sh->dev[r6s->failed_num[0]]; 2407 s->locked++; 2408 set_bit(R5_LOCKED, &dev->flags); 2409 set_bit(R5_Wantwrite, &dev->flags); 2410 } 2411 2412 if (update_p) { 2413 dev = &sh->dev[pd_idx]; 2414 s->locked++; 2415 set_bit(R5_LOCKED, &dev->flags); 2416 set_bit(R5_Wantwrite, &dev->flags); 2417 } 2418 if (update_q) { 2419 dev = &sh->dev[qd_idx]; 2420 s->locked++; 2421 set_bit(R5_LOCKED, &dev->flags); 2422 set_bit(R5_Wantwrite, &dev->flags); 2423 } 2424 clear_bit(STRIPE_DEGRADED, &sh->state); 2425 2426 set_bit(STRIPE_INSYNC, &sh->state); 2427 } 2428 } 2429 2430 static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, 2431 struct r6_state *r6s) 2432 { 2433 int i; 2434 2435 /* We have read all the blocks in this stripe and now we need to 2436 * copy some of them into a target stripe for expand. 2437 */ 2438 struct dma_async_tx_descriptor *tx = NULL; 2439 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2440 for (i = 0; i < sh->disks; i++) 2441 if (i != sh->pd_idx && (!r6s || i != r6s->qd_idx)) { 2442 int dd_idx, pd_idx, j; 2443 struct stripe_head *sh2; 2444 2445 sector_t bn = compute_blocknr(sh, i); 2446 sector_t s = raid5_compute_sector(bn, conf->raid_disks, 2447 conf->raid_disks - 2448 conf->max_degraded, &dd_idx, 2449 &pd_idx, conf); 2450 sh2 = get_active_stripe(conf, s, conf->raid_disks, 2451 pd_idx, 1); 2452 if (sh2 == NULL) 2453 /* so far only the early blocks of this stripe 2454 * have been requested. When later blocks 2455 * get requested, we will try again 2456 */ 2457 continue; 2458 if (!test_bit(STRIPE_EXPANDING, &sh2->state) || 2459 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) { 2460 /* must have already done this block */ 2461 release_stripe(sh2); 2462 continue; 2463 } 2464 2465 /* place all the copies on one channel */ 2466 tx = async_memcpy(sh2->dev[dd_idx].page, 2467 sh->dev[i].page, 0, 0, STRIPE_SIZE, 2468 ASYNC_TX_DEP_ACK, tx, NULL, NULL); 2469 2470 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags); 2471 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags); 2472 for (j = 0; j < conf->raid_disks; j++) 2473 if (j != sh2->pd_idx && 2474 (!r6s || j != raid6_next_disk(sh2->pd_idx, 2475 sh2->disks)) && 2476 !test_bit(R5_Expanded, &sh2->dev[j].flags)) 2477 break; 2478 if (j == conf->raid_disks) { 2479 set_bit(STRIPE_EXPAND_READY, &sh2->state); 2480 set_bit(STRIPE_HANDLE, &sh2->state); 2481 } 2482 release_stripe(sh2); 2483 2484 } 2485 /* done submitting copies, wait for them to complete */ 2486 if (tx) { 2487 async_tx_ack(tx); 2488 dma_wait_for_async_tx(tx); 2489 } 2490 } 2491 2492 2493 /* 2494 * handle_stripe - do things to a stripe. 2495 * 2496 * We lock the stripe and then examine the state of various bits 2497 * to see what needs to be done. 2498 * Possible results: 2499 * return some read request which now have data 2500 * return some write requests which are safely on disc 2501 * schedule a read on some buffers 2502 * schedule a write of some buffers 2503 * return confirmation of parity correctness 2504 * 2505 * buffers are taken off read_list or write_list, and bh_cache buffers 2506 * get BH_Lock set before the stripe lock is released. 2507 * 2508 */ 2509 2510 static void handle_stripe5(struct stripe_head *sh) 2511 { 2512 raid5_conf_t *conf = sh->raid_conf; 2513 int disks = sh->disks, i; 2514 struct bio *return_bi = NULL; 2515 struct stripe_head_state s; 2516 struct r5dev *dev; 2517 mdk_rdev_t *blocked_rdev = NULL; 2518 int prexor; 2519 2520 memset(&s, 0, sizeof(s)); 2521 pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d " 2522 "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state, 2523 atomic_read(&sh->count), sh->pd_idx, sh->check_state, 2524 sh->reconstruct_state); 2525 2526 spin_lock(&sh->lock); 2527 clear_bit(STRIPE_HANDLE, &sh->state); 2528 clear_bit(STRIPE_DELAYED, &sh->state); 2529 2530 s.syncing = test_bit(STRIPE_SYNCING, &sh->state); 2531 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2532 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 2533 2534 /* Now to look around and see what can be done */ 2535 rcu_read_lock(); 2536 for (i=disks; i--; ) { 2537 mdk_rdev_t *rdev; 2538 struct r5dev *dev = &sh->dev[i]; 2539 clear_bit(R5_Insync, &dev->flags); 2540 2541 pr_debug("check %d: state 0x%lx toread %p read %p write %p " 2542 "written %p\n", i, dev->flags, dev->toread, dev->read, 2543 dev->towrite, dev->written); 2544 2545 /* maybe we can request a biofill operation 2546 * 2547 * new wantfill requests are only permitted while 2548 * ops_complete_biofill is guaranteed to be inactive 2549 */ 2550 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && 2551 !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) 2552 set_bit(R5_Wantfill, &dev->flags); 2553 2554 /* now count some things */ 2555 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; 2556 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; 2557 if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++; 2558 2559 if (test_bit(R5_Wantfill, &dev->flags)) 2560 s.to_fill++; 2561 else if (dev->toread) 2562 s.to_read++; 2563 if (dev->towrite) { 2564 s.to_write++; 2565 if (!test_bit(R5_OVERWRITE, &dev->flags)) 2566 s.non_overwrite++; 2567 } 2568 if (dev->written) 2569 s.written++; 2570 rdev = rcu_dereference(conf->disks[i].rdev); 2571 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 2572 blocked_rdev = rdev; 2573 atomic_inc(&rdev->nr_pending); 2574 break; 2575 } 2576 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 2577 /* The ReadError flag will just be confusing now */ 2578 clear_bit(R5_ReadError, &dev->flags); 2579 clear_bit(R5_ReWrite, &dev->flags); 2580 } 2581 if (!rdev || !test_bit(In_sync, &rdev->flags) 2582 || test_bit(R5_ReadError, &dev->flags)) { 2583 s.failed++; 2584 s.failed_num = i; 2585 } else 2586 set_bit(R5_Insync, &dev->flags); 2587 } 2588 rcu_read_unlock(); 2589 2590 if (unlikely(blocked_rdev)) { 2591 set_bit(STRIPE_HANDLE, &sh->state); 2592 goto unlock; 2593 } 2594 2595 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) { 2596 set_bit(STRIPE_OP_BIOFILL, &s.ops_request); 2597 set_bit(STRIPE_BIOFILL_RUN, &sh->state); 2598 } 2599 2600 pr_debug("locked=%d uptodate=%d to_read=%d" 2601 " to_write=%d failed=%d failed_num=%d\n", 2602 s.locked, s.uptodate, s.to_read, s.to_write, 2603 s.failed, s.failed_num); 2604 /* check if the array has lost two devices and, if so, some requests might 2605 * need to be failed 2606 */ 2607 if (s.failed > 1 && s.to_read+s.to_write+s.written) 2608 handle_failed_stripe(conf, sh, &s, disks, &return_bi); 2609 if (s.failed > 1 && s.syncing) { 2610 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 2611 clear_bit(STRIPE_SYNCING, &sh->state); 2612 s.syncing = 0; 2613 } 2614 2615 /* might be able to return some write requests if the parity block 2616 * is safe, or on a failed drive 2617 */ 2618 dev = &sh->dev[sh->pd_idx]; 2619 if ( s.written && 2620 ((test_bit(R5_Insync, &dev->flags) && 2621 !test_bit(R5_LOCKED, &dev->flags) && 2622 test_bit(R5_UPTODATE, &dev->flags)) || 2623 (s.failed == 1 && s.failed_num == sh->pd_idx))) 2624 handle_stripe_clean_event(conf, sh, disks, &return_bi); 2625 2626 /* Now we might consider reading some blocks, either to check/generate 2627 * parity, or to satisfy requests 2628 * or to load a block that is being partially written. 2629 */ 2630 if (s.to_read || s.non_overwrite || 2631 (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding) 2632 handle_stripe_fill5(sh, &s, disks); 2633 2634 /* Now we check to see if any write operations have recently 2635 * completed 2636 */ 2637 prexor = 0; 2638 if (sh->reconstruct_state == reconstruct_state_prexor_drain_result) 2639 prexor = 1; 2640 if (sh->reconstruct_state == reconstruct_state_drain_result || 2641 sh->reconstruct_state == reconstruct_state_prexor_drain_result) { 2642 sh->reconstruct_state = reconstruct_state_idle; 2643 2644 /* All the 'written' buffers and the parity block are ready to 2645 * be written back to disk 2646 */ 2647 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); 2648 for (i = disks; i--; ) { 2649 dev = &sh->dev[i]; 2650 if (test_bit(R5_LOCKED, &dev->flags) && 2651 (i == sh->pd_idx || dev->written)) { 2652 pr_debug("Writing block %d\n", i); 2653 set_bit(R5_Wantwrite, &dev->flags); 2654 if (prexor) 2655 continue; 2656 if (!test_bit(R5_Insync, &dev->flags) || 2657 (i == sh->pd_idx && s.failed == 0)) 2658 set_bit(STRIPE_INSYNC, &sh->state); 2659 } 2660 } 2661 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2662 atomic_dec(&conf->preread_active_stripes); 2663 if (atomic_read(&conf->preread_active_stripes) < 2664 IO_THRESHOLD) 2665 md_wakeup_thread(conf->mddev->thread); 2666 } 2667 } 2668 2669 /* Now to consider new write requests and what else, if anything 2670 * should be read. We do not handle new writes when: 2671 * 1/ A 'write' operation (copy+xor) is already in flight. 2672 * 2/ A 'check' operation is in flight, as it may clobber the parity 2673 * block. 2674 */ 2675 if (s.to_write && !sh->reconstruct_state && !sh->check_state) 2676 handle_stripe_dirtying5(conf, sh, &s, disks); 2677 2678 /* maybe we need to check and possibly fix the parity for this stripe 2679 * Any reads will already have been scheduled, so we just see if enough 2680 * data is available. The parity check is held off while parity 2681 * dependent operations are in flight. 2682 */ 2683 if (sh->check_state || 2684 (s.syncing && s.locked == 0 && 2685 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) && 2686 !test_bit(STRIPE_INSYNC, &sh->state))) 2687 handle_parity_checks5(conf, sh, &s, disks); 2688 2689 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 2690 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 2691 clear_bit(STRIPE_SYNCING, &sh->state); 2692 } 2693 2694 /* If the failed drive is just a ReadError, then we might need to progress 2695 * the repair/check process 2696 */ 2697 if (s.failed == 1 && !conf->mddev->ro && 2698 test_bit(R5_ReadError, &sh->dev[s.failed_num].flags) 2699 && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags) 2700 && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags) 2701 ) { 2702 dev = &sh->dev[s.failed_num]; 2703 if (!test_bit(R5_ReWrite, &dev->flags)) { 2704 set_bit(R5_Wantwrite, &dev->flags); 2705 set_bit(R5_ReWrite, &dev->flags); 2706 set_bit(R5_LOCKED, &dev->flags); 2707 s.locked++; 2708 } else { 2709 /* let's read it back */ 2710 set_bit(R5_Wantread, &dev->flags); 2711 set_bit(R5_LOCKED, &dev->flags); 2712 s.locked++; 2713 } 2714 } 2715 2716 /* Finish reconstruct operations initiated by the expansion process */ 2717 if (sh->reconstruct_state == reconstruct_state_result) { 2718 sh->reconstruct_state = reconstruct_state_idle; 2719 clear_bit(STRIPE_EXPANDING, &sh->state); 2720 for (i = conf->raid_disks; i--; ) 2721 set_bit(R5_Wantwrite, &sh->dev[i].flags); 2722 set_bit(R5_LOCKED, &dev->flags); 2723 s.locked++; 2724 } 2725 2726 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) && 2727 !sh->reconstruct_state) { 2728 /* Need to write out all blocks after computing parity */ 2729 sh->disks = conf->raid_disks; 2730 sh->pd_idx = stripe_to_pdidx(sh->sector, conf, 2731 conf->raid_disks); 2732 schedule_reconstruction5(sh, &s, 1, 1); 2733 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) { 2734 clear_bit(STRIPE_EXPAND_READY, &sh->state); 2735 atomic_dec(&conf->reshape_stripes); 2736 wake_up(&conf->wait_for_overlap); 2737 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 2738 } 2739 2740 if (s.expanding && s.locked == 0 && 2741 !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) 2742 handle_stripe_expansion(conf, sh, NULL); 2743 2744 unlock: 2745 spin_unlock(&sh->lock); 2746 2747 /* wait for this device to become unblocked */ 2748 if (unlikely(blocked_rdev)) 2749 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); 2750 2751 if (s.ops_request) 2752 raid5_run_ops(sh, s.ops_request); 2753 2754 ops_run_io(sh, &s); 2755 2756 return_io(return_bi); 2757 } 2758 2759 static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page) 2760 { 2761 raid6_conf_t *conf = sh->raid_conf; 2762 int disks = sh->disks; 2763 struct bio *return_bi = NULL; 2764 int i, pd_idx = sh->pd_idx; 2765 struct stripe_head_state s; 2766 struct r6_state r6s; 2767 struct r5dev *dev, *pdev, *qdev; 2768 mdk_rdev_t *blocked_rdev = NULL; 2769 2770 r6s.qd_idx = raid6_next_disk(pd_idx, disks); 2771 pr_debug("handling stripe %llu, state=%#lx cnt=%d, " 2772 "pd_idx=%d, qd_idx=%d\n", 2773 (unsigned long long)sh->sector, sh->state, 2774 atomic_read(&sh->count), pd_idx, r6s.qd_idx); 2775 memset(&s, 0, sizeof(s)); 2776 2777 spin_lock(&sh->lock); 2778 clear_bit(STRIPE_HANDLE, &sh->state); 2779 clear_bit(STRIPE_DELAYED, &sh->state); 2780 2781 s.syncing = test_bit(STRIPE_SYNCING, &sh->state); 2782 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2783 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 2784 /* Now to look around and see what can be done */ 2785 2786 rcu_read_lock(); 2787 for (i=disks; i--; ) { 2788 mdk_rdev_t *rdev; 2789 dev = &sh->dev[i]; 2790 clear_bit(R5_Insync, &dev->flags); 2791 2792 pr_debug("check %d: state 0x%lx read %p write %p written %p\n", 2793 i, dev->flags, dev->toread, dev->towrite, dev->written); 2794 /* maybe we can reply to a read */ 2795 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { 2796 struct bio *rbi, *rbi2; 2797 pr_debug("Return read for disc %d\n", i); 2798 spin_lock_irq(&conf->device_lock); 2799 rbi = dev->toread; 2800 dev->toread = NULL; 2801 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 2802 wake_up(&conf->wait_for_overlap); 2803 spin_unlock_irq(&conf->device_lock); 2804 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { 2805 copy_data(0, rbi, dev->page, dev->sector); 2806 rbi2 = r5_next_bio(rbi, dev->sector); 2807 spin_lock_irq(&conf->device_lock); 2808 if (--rbi->bi_phys_segments == 0) { 2809 rbi->bi_next = return_bi; 2810 return_bi = rbi; 2811 } 2812 spin_unlock_irq(&conf->device_lock); 2813 rbi = rbi2; 2814 } 2815 } 2816 2817 /* now count some things */ 2818 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; 2819 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; 2820 2821 2822 if (dev->toread) 2823 s.to_read++; 2824 if (dev->towrite) { 2825 s.to_write++; 2826 if (!test_bit(R5_OVERWRITE, &dev->flags)) 2827 s.non_overwrite++; 2828 } 2829 if (dev->written) 2830 s.written++; 2831 rdev = rcu_dereference(conf->disks[i].rdev); 2832 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 2833 blocked_rdev = rdev; 2834 atomic_inc(&rdev->nr_pending); 2835 break; 2836 } 2837 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 2838 /* The ReadError flag will just be confusing now */ 2839 clear_bit(R5_ReadError, &dev->flags); 2840 clear_bit(R5_ReWrite, &dev->flags); 2841 } 2842 if (!rdev || !test_bit(In_sync, &rdev->flags) 2843 || test_bit(R5_ReadError, &dev->flags)) { 2844 if (s.failed < 2) 2845 r6s.failed_num[s.failed] = i; 2846 s.failed++; 2847 } else 2848 set_bit(R5_Insync, &dev->flags); 2849 } 2850 rcu_read_unlock(); 2851 2852 if (unlikely(blocked_rdev)) { 2853 set_bit(STRIPE_HANDLE, &sh->state); 2854 goto unlock; 2855 } 2856 pr_debug("locked=%d uptodate=%d to_read=%d" 2857 " to_write=%d failed=%d failed_num=%d,%d\n", 2858 s.locked, s.uptodate, s.to_read, s.to_write, s.failed, 2859 r6s.failed_num[0], r6s.failed_num[1]); 2860 /* check if the array has lost >2 devices and, if so, some requests 2861 * might need to be failed 2862 */ 2863 if (s.failed > 2 && s.to_read+s.to_write+s.written) 2864 handle_failed_stripe(conf, sh, &s, disks, &return_bi); 2865 if (s.failed > 2 && s.syncing) { 2866 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 2867 clear_bit(STRIPE_SYNCING, &sh->state); 2868 s.syncing = 0; 2869 } 2870 2871 /* 2872 * might be able to return some write requests if the parity blocks 2873 * are safe, or on a failed drive 2874 */ 2875 pdev = &sh->dev[pd_idx]; 2876 r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx) 2877 || (s.failed >= 2 && r6s.failed_num[1] == pd_idx); 2878 qdev = &sh->dev[r6s.qd_idx]; 2879 r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == r6s.qd_idx) 2880 || (s.failed >= 2 && r6s.failed_num[1] == r6s.qd_idx); 2881 2882 if ( s.written && 2883 ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags) 2884 && !test_bit(R5_LOCKED, &pdev->flags) 2885 && test_bit(R5_UPTODATE, &pdev->flags)))) && 2886 ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags) 2887 && !test_bit(R5_LOCKED, &qdev->flags) 2888 && test_bit(R5_UPTODATE, &qdev->flags))))) 2889 handle_stripe_clean_event(conf, sh, disks, &return_bi); 2890 2891 /* Now we might consider reading some blocks, either to check/generate 2892 * parity, or to satisfy requests 2893 * or to load a block that is being partially written. 2894 */ 2895 if (s.to_read || s.non_overwrite || (s.to_write && s.failed) || 2896 (s.syncing && (s.uptodate < disks)) || s.expanding) 2897 handle_stripe_fill6(sh, &s, &r6s, disks); 2898 2899 /* now to consider writing and what else, if anything should be read */ 2900 if (s.to_write) 2901 handle_stripe_dirtying6(conf, sh, &s, &r6s, disks); 2902 2903 /* maybe we need to check and possibly fix the parity for this stripe 2904 * Any reads will already have been scheduled, so we just see if enough 2905 * data is available 2906 */ 2907 if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state)) 2908 handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks); 2909 2910 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 2911 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 2912 clear_bit(STRIPE_SYNCING, &sh->state); 2913 } 2914 2915 /* If the failed drives are just a ReadError, then we might need 2916 * to progress the repair/check process 2917 */ 2918 if (s.failed <= 2 && !conf->mddev->ro) 2919 for (i = 0; i < s.failed; i++) { 2920 dev = &sh->dev[r6s.failed_num[i]]; 2921 if (test_bit(R5_ReadError, &dev->flags) 2922 && !test_bit(R5_LOCKED, &dev->flags) 2923 && test_bit(R5_UPTODATE, &dev->flags) 2924 ) { 2925 if (!test_bit(R5_ReWrite, &dev->flags)) { 2926 set_bit(R5_Wantwrite, &dev->flags); 2927 set_bit(R5_ReWrite, &dev->flags); 2928 set_bit(R5_LOCKED, &dev->flags); 2929 } else { 2930 /* let's read it back */ 2931 set_bit(R5_Wantread, &dev->flags); 2932 set_bit(R5_LOCKED, &dev->flags); 2933 } 2934 } 2935 } 2936 2937 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) { 2938 /* Need to write out all blocks after computing P&Q */ 2939 sh->disks = conf->raid_disks; 2940 sh->pd_idx = stripe_to_pdidx(sh->sector, conf, 2941 conf->raid_disks); 2942 compute_parity6(sh, RECONSTRUCT_WRITE); 2943 for (i = conf->raid_disks ; i-- ; ) { 2944 set_bit(R5_LOCKED, &sh->dev[i].flags); 2945 s.locked++; 2946 set_bit(R5_Wantwrite, &sh->dev[i].flags); 2947 } 2948 clear_bit(STRIPE_EXPANDING, &sh->state); 2949 } else if (s.expanded) { 2950 clear_bit(STRIPE_EXPAND_READY, &sh->state); 2951 atomic_dec(&conf->reshape_stripes); 2952 wake_up(&conf->wait_for_overlap); 2953 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 2954 } 2955 2956 if (s.expanding && s.locked == 0 && 2957 !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) 2958 handle_stripe_expansion(conf, sh, &r6s); 2959 2960 unlock: 2961 spin_unlock(&sh->lock); 2962 2963 /* wait for this device to become unblocked */ 2964 if (unlikely(blocked_rdev)) 2965 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); 2966 2967 ops_run_io(sh, &s); 2968 2969 return_io(return_bi); 2970 } 2971 2972 static void handle_stripe(struct stripe_head *sh, struct page *tmp_page) 2973 { 2974 if (sh->raid_conf->level == 6) 2975 handle_stripe6(sh, tmp_page); 2976 else 2977 handle_stripe5(sh); 2978 } 2979 2980 2981 2982 static void raid5_activate_delayed(raid5_conf_t *conf) 2983 { 2984 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { 2985 while (!list_empty(&conf->delayed_list)) { 2986 struct list_head *l = conf->delayed_list.next; 2987 struct stripe_head *sh; 2988 sh = list_entry(l, struct stripe_head, lru); 2989 list_del_init(l); 2990 clear_bit(STRIPE_DELAYED, &sh->state); 2991 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 2992 atomic_inc(&conf->preread_active_stripes); 2993 list_add_tail(&sh->lru, &conf->hold_list); 2994 } 2995 } else 2996 blk_plug_device(conf->mddev->queue); 2997 } 2998 2999 static void activate_bit_delay(raid5_conf_t *conf) 3000 { 3001 /* device_lock is held */ 3002 struct list_head head; 3003 list_add(&head, &conf->bitmap_list); 3004 list_del_init(&conf->bitmap_list); 3005 while (!list_empty(&head)) { 3006 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); 3007 list_del_init(&sh->lru); 3008 atomic_inc(&sh->count); 3009 __release_stripe(conf, sh); 3010 } 3011 } 3012 3013 static void unplug_slaves(mddev_t *mddev) 3014 { 3015 raid5_conf_t *conf = mddev_to_conf(mddev); 3016 int i; 3017 3018 rcu_read_lock(); 3019 for (i=0; i<mddev->raid_disks; i++) { 3020 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 3021 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 3022 struct request_queue *r_queue = bdev_get_queue(rdev->bdev); 3023 3024 atomic_inc(&rdev->nr_pending); 3025 rcu_read_unlock(); 3026 3027 blk_unplug(r_queue); 3028 3029 rdev_dec_pending(rdev, mddev); 3030 rcu_read_lock(); 3031 } 3032 } 3033 rcu_read_unlock(); 3034 } 3035 3036 static void raid5_unplug_device(struct request_queue *q) 3037 { 3038 mddev_t *mddev = q->queuedata; 3039 raid5_conf_t *conf = mddev_to_conf(mddev); 3040 unsigned long flags; 3041 3042 spin_lock_irqsave(&conf->device_lock, flags); 3043 3044 if (blk_remove_plug(q)) { 3045 conf->seq_flush++; 3046 raid5_activate_delayed(conf); 3047 } 3048 md_wakeup_thread(mddev->thread); 3049 3050 spin_unlock_irqrestore(&conf->device_lock, flags); 3051 3052 unplug_slaves(mddev); 3053 } 3054 3055 static int raid5_congested(void *data, int bits) 3056 { 3057 mddev_t *mddev = data; 3058 raid5_conf_t *conf = mddev_to_conf(mddev); 3059 3060 /* No difference between reads and writes. Just check 3061 * how busy the stripe_cache is 3062 */ 3063 if (conf->inactive_blocked) 3064 return 1; 3065 if (conf->quiesce) 3066 return 1; 3067 if (list_empty_careful(&conf->inactive_list)) 3068 return 1; 3069 3070 return 0; 3071 } 3072 3073 /* We want read requests to align with chunks where possible, 3074 * but write requests don't need to. 3075 */ 3076 static int raid5_mergeable_bvec(struct request_queue *q, 3077 struct bvec_merge_data *bvm, 3078 struct bio_vec *biovec) 3079 { 3080 mddev_t *mddev = q->queuedata; 3081 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 3082 int max; 3083 unsigned int chunk_sectors = mddev->chunk_size >> 9; 3084 unsigned int bio_sectors = bvm->bi_size >> 9; 3085 3086 if ((bvm->bi_rw & 1) == WRITE) 3087 return biovec->bv_len; /* always allow writes to be mergeable */ 3088 3089 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; 3090 if (max < 0) max = 0; 3091 if (max <= biovec->bv_len && bio_sectors == 0) 3092 return biovec->bv_len; 3093 else 3094 return max; 3095 } 3096 3097 3098 static int in_chunk_boundary(mddev_t *mddev, struct bio *bio) 3099 { 3100 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); 3101 unsigned int chunk_sectors = mddev->chunk_size >> 9; 3102 unsigned int bio_sectors = bio->bi_size >> 9; 3103 3104 return chunk_sectors >= 3105 ((sector & (chunk_sectors - 1)) + bio_sectors); 3106 } 3107 3108 /* 3109 * add bio to the retry LIFO ( in O(1) ... we are in interrupt ) 3110 * later sampled by raid5d. 3111 */ 3112 static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf) 3113 { 3114 unsigned long flags; 3115 3116 spin_lock_irqsave(&conf->device_lock, flags); 3117 3118 bi->bi_next = conf->retry_read_aligned_list; 3119 conf->retry_read_aligned_list = bi; 3120 3121 spin_unlock_irqrestore(&conf->device_lock, flags); 3122 md_wakeup_thread(conf->mddev->thread); 3123 } 3124 3125 3126 static struct bio *remove_bio_from_retry(raid5_conf_t *conf) 3127 { 3128 struct bio *bi; 3129 3130 bi = conf->retry_read_aligned; 3131 if (bi) { 3132 conf->retry_read_aligned = NULL; 3133 return bi; 3134 } 3135 bi = conf->retry_read_aligned_list; 3136 if(bi) { 3137 conf->retry_read_aligned_list = bi->bi_next; 3138 bi->bi_next = NULL; 3139 bi->bi_phys_segments = 1; /* biased count of active stripes */ 3140 bi->bi_hw_segments = 0; /* count of processed stripes */ 3141 } 3142 3143 return bi; 3144 } 3145 3146 3147 /* 3148 * The "raid5_align_endio" should check if the read succeeded and if it 3149 * did, call bio_endio on the original bio (having bio_put the new bio 3150 * first). 3151 * If the read failed.. 3152 */ 3153 static void raid5_align_endio(struct bio *bi, int error) 3154 { 3155 struct bio* raid_bi = bi->bi_private; 3156 mddev_t *mddev; 3157 raid5_conf_t *conf; 3158 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 3159 mdk_rdev_t *rdev; 3160 3161 bio_put(bi); 3162 3163 mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata; 3164 conf = mddev_to_conf(mddev); 3165 rdev = (void*)raid_bi->bi_next; 3166 raid_bi->bi_next = NULL; 3167 3168 rdev_dec_pending(rdev, conf->mddev); 3169 3170 if (!error && uptodate) { 3171 bio_endio(raid_bi, 0); 3172 if (atomic_dec_and_test(&conf->active_aligned_reads)) 3173 wake_up(&conf->wait_for_stripe); 3174 return; 3175 } 3176 3177 3178 pr_debug("raid5_align_endio : io error...handing IO for a retry\n"); 3179 3180 add_bio_to_retry(raid_bi, conf); 3181 } 3182 3183 static int bio_fits_rdev(struct bio *bi) 3184 { 3185 struct request_queue *q = bdev_get_queue(bi->bi_bdev); 3186 3187 if ((bi->bi_size>>9) > q->max_sectors) 3188 return 0; 3189 blk_recount_segments(q, bi); 3190 if (bi->bi_phys_segments > q->max_phys_segments || 3191 bi->bi_hw_segments > q->max_hw_segments) 3192 return 0; 3193 3194 if (q->merge_bvec_fn) 3195 /* it's too hard to apply the merge_bvec_fn at this stage, 3196 * just just give up 3197 */ 3198 return 0; 3199 3200 return 1; 3201 } 3202 3203 3204 static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio) 3205 { 3206 mddev_t *mddev = q->queuedata; 3207 raid5_conf_t *conf = mddev_to_conf(mddev); 3208 const unsigned int raid_disks = conf->raid_disks; 3209 const unsigned int data_disks = raid_disks - conf->max_degraded; 3210 unsigned int dd_idx, pd_idx; 3211 struct bio* align_bi; 3212 mdk_rdev_t *rdev; 3213 3214 if (!in_chunk_boundary(mddev, raid_bio)) { 3215 pr_debug("chunk_aligned_read : non aligned\n"); 3216 return 0; 3217 } 3218 /* 3219 * use bio_clone to make a copy of the bio 3220 */ 3221 align_bi = bio_clone(raid_bio, GFP_NOIO); 3222 if (!align_bi) 3223 return 0; 3224 /* 3225 * set bi_end_io to a new function, and set bi_private to the 3226 * original bio. 3227 */ 3228 align_bi->bi_end_io = raid5_align_endio; 3229 align_bi->bi_private = raid_bio; 3230 /* 3231 * compute position 3232 */ 3233 align_bi->bi_sector = raid5_compute_sector(raid_bio->bi_sector, 3234 raid_disks, 3235 data_disks, 3236 &dd_idx, 3237 &pd_idx, 3238 conf); 3239 3240 rcu_read_lock(); 3241 rdev = rcu_dereference(conf->disks[dd_idx].rdev); 3242 if (rdev && test_bit(In_sync, &rdev->flags)) { 3243 atomic_inc(&rdev->nr_pending); 3244 rcu_read_unlock(); 3245 raid_bio->bi_next = (void*)rdev; 3246 align_bi->bi_bdev = rdev->bdev; 3247 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID); 3248 align_bi->bi_sector += rdev->data_offset; 3249 3250 if (!bio_fits_rdev(align_bi)) { 3251 /* too big in some way */ 3252 bio_put(align_bi); 3253 rdev_dec_pending(rdev, mddev); 3254 return 0; 3255 } 3256 3257 spin_lock_irq(&conf->device_lock); 3258 wait_event_lock_irq(conf->wait_for_stripe, 3259 conf->quiesce == 0, 3260 conf->device_lock, /* nothing */); 3261 atomic_inc(&conf->active_aligned_reads); 3262 spin_unlock_irq(&conf->device_lock); 3263 3264 generic_make_request(align_bi); 3265 return 1; 3266 } else { 3267 rcu_read_unlock(); 3268 bio_put(align_bi); 3269 return 0; 3270 } 3271 } 3272 3273 /* __get_priority_stripe - get the next stripe to process 3274 * 3275 * Full stripe writes are allowed to pass preread active stripes up until 3276 * the bypass_threshold is exceeded. In general the bypass_count 3277 * increments when the handle_list is handled before the hold_list; however, it 3278 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a 3279 * stripe with in flight i/o. The bypass_count will be reset when the 3280 * head of the hold_list has changed, i.e. the head was promoted to the 3281 * handle_list. 3282 */ 3283 static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf) 3284 { 3285 struct stripe_head *sh; 3286 3287 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n", 3288 __func__, 3289 list_empty(&conf->handle_list) ? "empty" : "busy", 3290 list_empty(&conf->hold_list) ? "empty" : "busy", 3291 atomic_read(&conf->pending_full_writes), conf->bypass_count); 3292 3293 if (!list_empty(&conf->handle_list)) { 3294 sh = list_entry(conf->handle_list.next, typeof(*sh), lru); 3295 3296 if (list_empty(&conf->hold_list)) 3297 conf->bypass_count = 0; 3298 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) { 3299 if (conf->hold_list.next == conf->last_hold) 3300 conf->bypass_count++; 3301 else { 3302 conf->last_hold = conf->hold_list.next; 3303 conf->bypass_count -= conf->bypass_threshold; 3304 if (conf->bypass_count < 0) 3305 conf->bypass_count = 0; 3306 } 3307 } 3308 } else if (!list_empty(&conf->hold_list) && 3309 ((conf->bypass_threshold && 3310 conf->bypass_count > conf->bypass_threshold) || 3311 atomic_read(&conf->pending_full_writes) == 0)) { 3312 sh = list_entry(conf->hold_list.next, 3313 typeof(*sh), lru); 3314 conf->bypass_count -= conf->bypass_threshold; 3315 if (conf->bypass_count < 0) 3316 conf->bypass_count = 0; 3317 } else 3318 return NULL; 3319 3320 list_del_init(&sh->lru); 3321 atomic_inc(&sh->count); 3322 BUG_ON(atomic_read(&sh->count) != 1); 3323 return sh; 3324 } 3325 3326 static int make_request(struct request_queue *q, struct bio * bi) 3327 { 3328 mddev_t *mddev = q->queuedata; 3329 raid5_conf_t *conf = mddev_to_conf(mddev); 3330 unsigned int dd_idx, pd_idx; 3331 sector_t new_sector; 3332 sector_t logical_sector, last_sector; 3333 struct stripe_head *sh; 3334 const int rw = bio_data_dir(bi); 3335 int remaining; 3336 3337 if (unlikely(bio_barrier(bi))) { 3338 bio_endio(bi, -EOPNOTSUPP); 3339 return 0; 3340 } 3341 3342 md_write_start(mddev, bi); 3343 3344 disk_stat_inc(mddev->gendisk, ios[rw]); 3345 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi)); 3346 3347 if (rw == READ && 3348 mddev->reshape_position == MaxSector && 3349 chunk_aligned_read(q,bi)) 3350 return 0; 3351 3352 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 3353 last_sector = bi->bi_sector + (bi->bi_size>>9); 3354 bi->bi_next = NULL; 3355 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ 3356 3357 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { 3358 DEFINE_WAIT(w); 3359 int disks, data_disks; 3360 3361 retry: 3362 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); 3363 if (likely(conf->expand_progress == MaxSector)) 3364 disks = conf->raid_disks; 3365 else { 3366 /* spinlock is needed as expand_progress may be 3367 * 64bit on a 32bit platform, and so it might be 3368 * possible to see a half-updated value 3369 * Ofcourse expand_progress could change after 3370 * the lock is dropped, so once we get a reference 3371 * to the stripe that we think it is, we will have 3372 * to check again. 3373 */ 3374 spin_lock_irq(&conf->device_lock); 3375 disks = conf->raid_disks; 3376 if (logical_sector >= conf->expand_progress) 3377 disks = conf->previous_raid_disks; 3378 else { 3379 if (logical_sector >= conf->expand_lo) { 3380 spin_unlock_irq(&conf->device_lock); 3381 schedule(); 3382 goto retry; 3383 } 3384 } 3385 spin_unlock_irq(&conf->device_lock); 3386 } 3387 data_disks = disks - conf->max_degraded; 3388 3389 new_sector = raid5_compute_sector(logical_sector, disks, data_disks, 3390 &dd_idx, &pd_idx, conf); 3391 pr_debug("raid5: make_request, sector %llu logical %llu\n", 3392 (unsigned long long)new_sector, 3393 (unsigned long long)logical_sector); 3394 3395 sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK)); 3396 if (sh) { 3397 if (unlikely(conf->expand_progress != MaxSector)) { 3398 /* expansion might have moved on while waiting for a 3399 * stripe, so we must do the range check again. 3400 * Expansion could still move past after this 3401 * test, but as we are holding a reference to 3402 * 'sh', we know that if that happens, 3403 * STRIPE_EXPANDING will get set and the expansion 3404 * won't proceed until we finish with the stripe. 3405 */ 3406 int must_retry = 0; 3407 spin_lock_irq(&conf->device_lock); 3408 if (logical_sector < conf->expand_progress && 3409 disks == conf->previous_raid_disks) 3410 /* mismatch, need to try again */ 3411 must_retry = 1; 3412 spin_unlock_irq(&conf->device_lock); 3413 if (must_retry) { 3414 release_stripe(sh); 3415 goto retry; 3416 } 3417 } 3418 /* FIXME what if we get a false positive because these 3419 * are being updated. 3420 */ 3421 if (logical_sector >= mddev->suspend_lo && 3422 logical_sector < mddev->suspend_hi) { 3423 release_stripe(sh); 3424 schedule(); 3425 goto retry; 3426 } 3427 3428 if (test_bit(STRIPE_EXPANDING, &sh->state) || 3429 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { 3430 /* Stripe is busy expanding or 3431 * add failed due to overlap. Flush everything 3432 * and wait a while 3433 */ 3434 raid5_unplug_device(mddev->queue); 3435 release_stripe(sh); 3436 schedule(); 3437 goto retry; 3438 } 3439 finish_wait(&conf->wait_for_overlap, &w); 3440 set_bit(STRIPE_HANDLE, &sh->state); 3441 clear_bit(STRIPE_DELAYED, &sh->state); 3442 release_stripe(sh); 3443 } else { 3444 /* cannot get stripe for read-ahead, just give-up */ 3445 clear_bit(BIO_UPTODATE, &bi->bi_flags); 3446 finish_wait(&conf->wait_for_overlap, &w); 3447 break; 3448 } 3449 3450 } 3451 spin_lock_irq(&conf->device_lock); 3452 remaining = --bi->bi_phys_segments; 3453 spin_unlock_irq(&conf->device_lock); 3454 if (remaining == 0) { 3455 3456 if ( rw == WRITE ) 3457 md_write_end(mddev); 3458 3459 bio_endio(bi, 0); 3460 } 3461 return 0; 3462 } 3463 3464 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped) 3465 { 3466 /* reshaping is quite different to recovery/resync so it is 3467 * handled quite separately ... here. 3468 * 3469 * On each call to sync_request, we gather one chunk worth of 3470 * destination stripes and flag them as expanding. 3471 * Then we find all the source stripes and request reads. 3472 * As the reads complete, handle_stripe will copy the data 3473 * into the destination stripe and release that stripe. 3474 */ 3475 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 3476 struct stripe_head *sh; 3477 int pd_idx; 3478 sector_t first_sector, last_sector; 3479 int raid_disks = conf->previous_raid_disks; 3480 int data_disks = raid_disks - conf->max_degraded; 3481 int new_data_disks = conf->raid_disks - conf->max_degraded; 3482 int i; 3483 int dd_idx; 3484 sector_t writepos, safepos, gap; 3485 3486 if (sector_nr == 0 && 3487 conf->expand_progress != 0) { 3488 /* restarting in the middle, skip the initial sectors */ 3489 sector_nr = conf->expand_progress; 3490 sector_div(sector_nr, new_data_disks); 3491 *skipped = 1; 3492 return sector_nr; 3493 } 3494 3495 /* we update the metadata when there is more than 3Meg 3496 * in the block range (that is rather arbitrary, should 3497 * probably be time based) or when the data about to be 3498 * copied would over-write the source of the data at 3499 * the front of the range. 3500 * i.e. one new_stripe forward from expand_progress new_maps 3501 * to after where expand_lo old_maps to 3502 */ 3503 writepos = conf->expand_progress + 3504 conf->chunk_size/512*(new_data_disks); 3505 sector_div(writepos, new_data_disks); 3506 safepos = conf->expand_lo; 3507 sector_div(safepos, data_disks); 3508 gap = conf->expand_progress - conf->expand_lo; 3509 3510 if (writepos >= safepos || 3511 gap > (new_data_disks)*3000*2 /*3Meg*/) { 3512 /* Cannot proceed until we've updated the superblock... */ 3513 wait_event(conf->wait_for_overlap, 3514 atomic_read(&conf->reshape_stripes)==0); 3515 mddev->reshape_position = conf->expand_progress; 3516 set_bit(MD_CHANGE_DEVS, &mddev->flags); 3517 md_wakeup_thread(mddev->thread); 3518 wait_event(mddev->sb_wait, mddev->flags == 0 || 3519 kthread_should_stop()); 3520 spin_lock_irq(&conf->device_lock); 3521 conf->expand_lo = mddev->reshape_position; 3522 spin_unlock_irq(&conf->device_lock); 3523 wake_up(&conf->wait_for_overlap); 3524 } 3525 3526 for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) { 3527 int j; 3528 int skipped = 0; 3529 pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks); 3530 sh = get_active_stripe(conf, sector_nr+i, 3531 conf->raid_disks, pd_idx, 0); 3532 set_bit(STRIPE_EXPANDING, &sh->state); 3533 atomic_inc(&conf->reshape_stripes); 3534 /* If any of this stripe is beyond the end of the old 3535 * array, then we need to zero those blocks 3536 */ 3537 for (j=sh->disks; j--;) { 3538 sector_t s; 3539 if (j == sh->pd_idx) 3540 continue; 3541 if (conf->level == 6 && 3542 j == raid6_next_disk(sh->pd_idx, sh->disks)) 3543 continue; 3544 s = compute_blocknr(sh, j); 3545 if (s < mddev->array_sectors) { 3546 skipped = 1; 3547 continue; 3548 } 3549 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE); 3550 set_bit(R5_Expanded, &sh->dev[j].flags); 3551 set_bit(R5_UPTODATE, &sh->dev[j].flags); 3552 } 3553 if (!skipped) { 3554 set_bit(STRIPE_EXPAND_READY, &sh->state); 3555 set_bit(STRIPE_HANDLE, &sh->state); 3556 } 3557 release_stripe(sh); 3558 } 3559 spin_lock_irq(&conf->device_lock); 3560 conf->expand_progress = (sector_nr + i) * new_data_disks; 3561 spin_unlock_irq(&conf->device_lock); 3562 /* Ok, those stripe are ready. We can start scheduling 3563 * reads on the source stripes. 3564 * The source stripes are determined by mapping the first and last 3565 * block on the destination stripes. 3566 */ 3567 first_sector = 3568 raid5_compute_sector(sector_nr*(new_data_disks), 3569 raid_disks, data_disks, 3570 &dd_idx, &pd_idx, conf); 3571 last_sector = 3572 raid5_compute_sector((sector_nr+conf->chunk_size/512) 3573 *(new_data_disks) -1, 3574 raid_disks, data_disks, 3575 &dd_idx, &pd_idx, conf); 3576 if (last_sector >= (mddev->size<<1)) 3577 last_sector = (mddev->size<<1)-1; 3578 while (first_sector <= last_sector) { 3579 pd_idx = stripe_to_pdidx(first_sector, conf, 3580 conf->previous_raid_disks); 3581 sh = get_active_stripe(conf, first_sector, 3582 conf->previous_raid_disks, pd_idx, 0); 3583 set_bit(STRIPE_EXPAND_SOURCE, &sh->state); 3584 set_bit(STRIPE_HANDLE, &sh->state); 3585 release_stripe(sh); 3586 first_sector += STRIPE_SECTORS; 3587 } 3588 /* If this takes us to the resync_max point where we have to pause, 3589 * then we need to write out the superblock. 3590 */ 3591 sector_nr += conf->chunk_size>>9; 3592 if (sector_nr >= mddev->resync_max) { 3593 /* Cannot proceed until we've updated the superblock... */ 3594 wait_event(conf->wait_for_overlap, 3595 atomic_read(&conf->reshape_stripes) == 0); 3596 mddev->reshape_position = conf->expand_progress; 3597 set_bit(MD_CHANGE_DEVS, &mddev->flags); 3598 md_wakeup_thread(mddev->thread); 3599 wait_event(mddev->sb_wait, 3600 !test_bit(MD_CHANGE_DEVS, &mddev->flags) 3601 || kthread_should_stop()); 3602 spin_lock_irq(&conf->device_lock); 3603 conf->expand_lo = mddev->reshape_position; 3604 spin_unlock_irq(&conf->device_lock); 3605 wake_up(&conf->wait_for_overlap); 3606 } 3607 return conf->chunk_size>>9; 3608 } 3609 3610 /* FIXME go_faster isn't used */ 3611 static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 3612 { 3613 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 3614 struct stripe_head *sh; 3615 int pd_idx; 3616 int raid_disks = conf->raid_disks; 3617 sector_t max_sector = mddev->size << 1; 3618 int sync_blocks; 3619 int still_degraded = 0; 3620 int i; 3621 3622 if (sector_nr >= max_sector) { 3623 /* just being told to finish up .. nothing much to do */ 3624 unplug_slaves(mddev); 3625 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) { 3626 end_reshape(conf); 3627 return 0; 3628 } 3629 3630 if (mddev->curr_resync < max_sector) /* aborted */ 3631 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 3632 &sync_blocks, 1); 3633 else /* completed sync */ 3634 conf->fullsync = 0; 3635 bitmap_close_sync(mddev->bitmap); 3636 3637 return 0; 3638 } 3639 3640 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) 3641 return reshape_request(mddev, sector_nr, skipped); 3642 3643 /* No need to check resync_max as we never do more than one 3644 * stripe, and as resync_max will always be on a chunk boundary, 3645 * if the check in md_do_sync didn't fire, there is no chance 3646 * of overstepping resync_max here 3647 */ 3648 3649 /* if there is too many failed drives and we are trying 3650 * to resync, then assert that we are finished, because there is 3651 * nothing we can do. 3652 */ 3653 if (mddev->degraded >= conf->max_degraded && 3654 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 3655 sector_t rv = (mddev->size << 1) - sector_nr; 3656 *skipped = 1; 3657 return rv; 3658 } 3659 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && 3660 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && 3661 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { 3662 /* we can skip this block, and probably more */ 3663 sync_blocks /= STRIPE_SECTORS; 3664 *skipped = 1; 3665 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ 3666 } 3667 3668 3669 bitmap_cond_end_sync(mddev->bitmap, sector_nr); 3670 3671 pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks); 3672 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1); 3673 if (sh == NULL) { 3674 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0); 3675 /* make sure we don't swamp the stripe cache if someone else 3676 * is trying to get access 3677 */ 3678 schedule_timeout_uninterruptible(1); 3679 } 3680 /* Need to check if array will still be degraded after recovery/resync 3681 * We don't need to check the 'failed' flag as when that gets set, 3682 * recovery aborts. 3683 */ 3684 for (i=0; i<mddev->raid_disks; i++) 3685 if (conf->disks[i].rdev == NULL) 3686 still_degraded = 1; 3687 3688 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded); 3689 3690 spin_lock(&sh->lock); 3691 set_bit(STRIPE_SYNCING, &sh->state); 3692 clear_bit(STRIPE_INSYNC, &sh->state); 3693 spin_unlock(&sh->lock); 3694 3695 handle_stripe(sh, NULL); 3696 release_stripe(sh); 3697 3698 return STRIPE_SECTORS; 3699 } 3700 3701 static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) 3702 { 3703 /* We may not be able to submit a whole bio at once as there 3704 * may not be enough stripe_heads available. 3705 * We cannot pre-allocate enough stripe_heads as we may need 3706 * more than exist in the cache (if we allow ever large chunks). 3707 * So we do one stripe head at a time and record in 3708 * ->bi_hw_segments how many have been done. 3709 * 3710 * We *know* that this entire raid_bio is in one chunk, so 3711 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector. 3712 */ 3713 struct stripe_head *sh; 3714 int dd_idx, pd_idx; 3715 sector_t sector, logical_sector, last_sector; 3716 int scnt = 0; 3717 int remaining; 3718 int handled = 0; 3719 3720 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 3721 sector = raid5_compute_sector( logical_sector, 3722 conf->raid_disks, 3723 conf->raid_disks - conf->max_degraded, 3724 &dd_idx, 3725 &pd_idx, 3726 conf); 3727 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9); 3728 3729 for (; logical_sector < last_sector; 3730 logical_sector += STRIPE_SECTORS, 3731 sector += STRIPE_SECTORS, 3732 scnt++) { 3733 3734 if (scnt < raid_bio->bi_hw_segments) 3735 /* already done this stripe */ 3736 continue; 3737 3738 sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1); 3739 3740 if (!sh) { 3741 /* failed to get a stripe - must wait */ 3742 raid_bio->bi_hw_segments = scnt; 3743 conf->retry_read_aligned = raid_bio; 3744 return handled; 3745 } 3746 3747 set_bit(R5_ReadError, &sh->dev[dd_idx].flags); 3748 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) { 3749 release_stripe(sh); 3750 raid_bio->bi_hw_segments = scnt; 3751 conf->retry_read_aligned = raid_bio; 3752 return handled; 3753 } 3754 3755 handle_stripe(sh, NULL); 3756 release_stripe(sh); 3757 handled++; 3758 } 3759 spin_lock_irq(&conf->device_lock); 3760 remaining = --raid_bio->bi_phys_segments; 3761 spin_unlock_irq(&conf->device_lock); 3762 if (remaining == 0) 3763 bio_endio(raid_bio, 0); 3764 if (atomic_dec_and_test(&conf->active_aligned_reads)) 3765 wake_up(&conf->wait_for_stripe); 3766 return handled; 3767 } 3768 3769 3770 3771 /* 3772 * This is our raid5 kernel thread. 3773 * 3774 * We scan the hash table for stripes which can be handled now. 3775 * During the scan, completed stripes are saved for us by the interrupt 3776 * handler, so that they will not have to wait for our next wakeup. 3777 */ 3778 static void raid5d(mddev_t *mddev) 3779 { 3780 struct stripe_head *sh; 3781 raid5_conf_t *conf = mddev_to_conf(mddev); 3782 int handled; 3783 3784 pr_debug("+++ raid5d active\n"); 3785 3786 md_check_recovery(mddev); 3787 3788 handled = 0; 3789 spin_lock_irq(&conf->device_lock); 3790 while (1) { 3791 struct bio *bio; 3792 3793 if (conf->seq_flush != conf->seq_write) { 3794 int seq = conf->seq_flush; 3795 spin_unlock_irq(&conf->device_lock); 3796 bitmap_unplug(mddev->bitmap); 3797 spin_lock_irq(&conf->device_lock); 3798 conf->seq_write = seq; 3799 activate_bit_delay(conf); 3800 } 3801 3802 while ((bio = remove_bio_from_retry(conf))) { 3803 int ok; 3804 spin_unlock_irq(&conf->device_lock); 3805 ok = retry_aligned_read(conf, bio); 3806 spin_lock_irq(&conf->device_lock); 3807 if (!ok) 3808 break; 3809 handled++; 3810 } 3811 3812 sh = __get_priority_stripe(conf); 3813 3814 if (!sh) { 3815 async_tx_issue_pending_all(); 3816 break; 3817 } 3818 spin_unlock_irq(&conf->device_lock); 3819 3820 handled++; 3821 handle_stripe(sh, conf->spare_page); 3822 release_stripe(sh); 3823 3824 spin_lock_irq(&conf->device_lock); 3825 } 3826 pr_debug("%d stripes handled\n", handled); 3827 3828 spin_unlock_irq(&conf->device_lock); 3829 3830 unplug_slaves(mddev); 3831 3832 pr_debug("--- raid5d inactive\n"); 3833 } 3834 3835 static ssize_t 3836 raid5_show_stripe_cache_size(mddev_t *mddev, char *page) 3837 { 3838 raid5_conf_t *conf = mddev_to_conf(mddev); 3839 if (conf) 3840 return sprintf(page, "%d\n", conf->max_nr_stripes); 3841 else 3842 return 0; 3843 } 3844 3845 static ssize_t 3846 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 3847 { 3848 raid5_conf_t *conf = mddev_to_conf(mddev); 3849 unsigned long new; 3850 int err; 3851 3852 if (len >= PAGE_SIZE) 3853 return -EINVAL; 3854 if (!conf) 3855 return -ENODEV; 3856 3857 if (strict_strtoul(page, 10, &new)) 3858 return -EINVAL; 3859 if (new <= 16 || new > 32768) 3860 return -EINVAL; 3861 while (new < conf->max_nr_stripes) { 3862 if (drop_one_stripe(conf)) 3863 conf->max_nr_stripes--; 3864 else 3865 break; 3866 } 3867 err = md_allow_write(mddev); 3868 if (err) 3869 return err; 3870 while (new > conf->max_nr_stripes) { 3871 if (grow_one_stripe(conf)) 3872 conf->max_nr_stripes++; 3873 else break; 3874 } 3875 return len; 3876 } 3877 3878 static struct md_sysfs_entry 3879 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, 3880 raid5_show_stripe_cache_size, 3881 raid5_store_stripe_cache_size); 3882 3883 static ssize_t 3884 raid5_show_preread_threshold(mddev_t *mddev, char *page) 3885 { 3886 raid5_conf_t *conf = mddev_to_conf(mddev); 3887 if (conf) 3888 return sprintf(page, "%d\n", conf->bypass_threshold); 3889 else 3890 return 0; 3891 } 3892 3893 static ssize_t 3894 raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len) 3895 { 3896 raid5_conf_t *conf = mddev_to_conf(mddev); 3897 unsigned long new; 3898 if (len >= PAGE_SIZE) 3899 return -EINVAL; 3900 if (!conf) 3901 return -ENODEV; 3902 3903 if (strict_strtoul(page, 10, &new)) 3904 return -EINVAL; 3905 if (new > conf->max_nr_stripes) 3906 return -EINVAL; 3907 conf->bypass_threshold = new; 3908 return len; 3909 } 3910 3911 static struct md_sysfs_entry 3912 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold, 3913 S_IRUGO | S_IWUSR, 3914 raid5_show_preread_threshold, 3915 raid5_store_preread_threshold); 3916 3917 static ssize_t 3918 stripe_cache_active_show(mddev_t *mddev, char *page) 3919 { 3920 raid5_conf_t *conf = mddev_to_conf(mddev); 3921 if (conf) 3922 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes)); 3923 else 3924 return 0; 3925 } 3926 3927 static struct md_sysfs_entry 3928 raid5_stripecache_active = __ATTR_RO(stripe_cache_active); 3929 3930 static struct attribute *raid5_attrs[] = { 3931 &raid5_stripecache_size.attr, 3932 &raid5_stripecache_active.attr, 3933 &raid5_preread_bypass_threshold.attr, 3934 NULL, 3935 }; 3936 static struct attribute_group raid5_attrs_group = { 3937 .name = NULL, 3938 .attrs = raid5_attrs, 3939 }; 3940 3941 static int run(mddev_t *mddev) 3942 { 3943 raid5_conf_t *conf; 3944 int raid_disk, memory; 3945 mdk_rdev_t *rdev; 3946 struct disk_info *disk; 3947 struct list_head *tmp; 3948 int working_disks = 0; 3949 3950 if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) { 3951 printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n", 3952 mdname(mddev), mddev->level); 3953 return -EIO; 3954 } 3955 3956 if (mddev->reshape_position != MaxSector) { 3957 /* Check that we can continue the reshape. 3958 * Currently only disks can change, it must 3959 * increase, and we must be past the point where 3960 * a stripe over-writes itself 3961 */ 3962 sector_t here_new, here_old; 3963 int old_disks; 3964 int max_degraded = (mddev->level == 5 ? 1 : 2); 3965 3966 if (mddev->new_level != mddev->level || 3967 mddev->new_layout != mddev->layout || 3968 mddev->new_chunk != mddev->chunk_size) { 3969 printk(KERN_ERR "raid5: %s: unsupported reshape " 3970 "required - aborting.\n", 3971 mdname(mddev)); 3972 return -EINVAL; 3973 } 3974 if (mddev->delta_disks <= 0) { 3975 printk(KERN_ERR "raid5: %s: unsupported reshape " 3976 "(reduce disks) required - aborting.\n", 3977 mdname(mddev)); 3978 return -EINVAL; 3979 } 3980 old_disks = mddev->raid_disks - mddev->delta_disks; 3981 /* reshape_position must be on a new-stripe boundary, and one 3982 * further up in new geometry must map after here in old 3983 * geometry. 3984 */ 3985 here_new = mddev->reshape_position; 3986 if (sector_div(here_new, (mddev->chunk_size>>9)* 3987 (mddev->raid_disks - max_degraded))) { 3988 printk(KERN_ERR "raid5: reshape_position not " 3989 "on a stripe boundary\n"); 3990 return -EINVAL; 3991 } 3992 /* here_new is the stripe we will write to */ 3993 here_old = mddev->reshape_position; 3994 sector_div(here_old, (mddev->chunk_size>>9)* 3995 (old_disks-max_degraded)); 3996 /* here_old is the first stripe that we might need to read 3997 * from */ 3998 if (here_new >= here_old) { 3999 /* Reading from the same stripe as writing to - bad */ 4000 printk(KERN_ERR "raid5: reshape_position too early for " 4001 "auto-recovery - aborting.\n"); 4002 return -EINVAL; 4003 } 4004 printk(KERN_INFO "raid5: reshape will continue\n"); 4005 /* OK, we should be able to continue; */ 4006 } 4007 4008 4009 mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL); 4010 if ((conf = mddev->private) == NULL) 4011 goto abort; 4012 if (mddev->reshape_position == MaxSector) { 4013 conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks; 4014 } else { 4015 conf->raid_disks = mddev->raid_disks; 4016 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks; 4017 } 4018 4019 conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info), 4020 GFP_KERNEL); 4021 if (!conf->disks) 4022 goto abort; 4023 4024 conf->mddev = mddev; 4025 4026 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) 4027 goto abort; 4028 4029 if (mddev->level == 6) { 4030 conf->spare_page = alloc_page(GFP_KERNEL); 4031 if (!conf->spare_page) 4032 goto abort; 4033 } 4034 spin_lock_init(&conf->device_lock); 4035 mddev->queue->queue_lock = &conf->device_lock; 4036 init_waitqueue_head(&conf->wait_for_stripe); 4037 init_waitqueue_head(&conf->wait_for_overlap); 4038 INIT_LIST_HEAD(&conf->handle_list); 4039 INIT_LIST_HEAD(&conf->hold_list); 4040 INIT_LIST_HEAD(&conf->delayed_list); 4041 INIT_LIST_HEAD(&conf->bitmap_list); 4042 INIT_LIST_HEAD(&conf->inactive_list); 4043 atomic_set(&conf->active_stripes, 0); 4044 atomic_set(&conf->preread_active_stripes, 0); 4045 atomic_set(&conf->active_aligned_reads, 0); 4046 conf->bypass_threshold = BYPASS_THRESHOLD; 4047 4048 pr_debug("raid5: run(%s) called.\n", mdname(mddev)); 4049 4050 rdev_for_each(rdev, tmp, mddev) { 4051 raid_disk = rdev->raid_disk; 4052 if (raid_disk >= conf->raid_disks 4053 || raid_disk < 0) 4054 continue; 4055 disk = conf->disks + raid_disk; 4056 4057 disk->rdev = rdev; 4058 4059 if (test_bit(In_sync, &rdev->flags)) { 4060 char b[BDEVNAME_SIZE]; 4061 printk(KERN_INFO "raid5: device %s operational as raid" 4062 " disk %d\n", bdevname(rdev->bdev,b), 4063 raid_disk); 4064 working_disks++; 4065 } else 4066 /* Cannot rely on bitmap to complete recovery */ 4067 conf->fullsync = 1; 4068 } 4069 4070 /* 4071 * 0 for a fully functional array, 1 or 2 for a degraded array. 4072 */ 4073 mddev->degraded = conf->raid_disks - working_disks; 4074 conf->mddev = mddev; 4075 conf->chunk_size = mddev->chunk_size; 4076 conf->level = mddev->level; 4077 if (conf->level == 6) 4078 conf->max_degraded = 2; 4079 else 4080 conf->max_degraded = 1; 4081 conf->algorithm = mddev->layout; 4082 conf->max_nr_stripes = NR_STRIPES; 4083 conf->expand_progress = mddev->reshape_position; 4084 4085 /* device size must be a multiple of chunk size */ 4086 mddev->size &= ~(mddev->chunk_size/1024 -1); 4087 mddev->resync_max_sectors = mddev->size << 1; 4088 4089 if (conf->level == 6 && conf->raid_disks < 4) { 4090 printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n", 4091 mdname(mddev), conf->raid_disks); 4092 goto abort; 4093 } 4094 if (!conf->chunk_size || conf->chunk_size % 4) { 4095 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", 4096 conf->chunk_size, mdname(mddev)); 4097 goto abort; 4098 } 4099 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) { 4100 printk(KERN_ERR 4101 "raid5: unsupported parity algorithm %d for %s\n", 4102 conf->algorithm, mdname(mddev)); 4103 goto abort; 4104 } 4105 if (mddev->degraded > conf->max_degraded) { 4106 printk(KERN_ERR "raid5: not enough operational devices for %s" 4107 " (%d/%d failed)\n", 4108 mdname(mddev), mddev->degraded, conf->raid_disks); 4109 goto abort; 4110 } 4111 4112 if (mddev->degraded > 0 && 4113 mddev->recovery_cp != MaxSector) { 4114 if (mddev->ok_start_degraded) 4115 printk(KERN_WARNING 4116 "raid5: starting dirty degraded array: %s" 4117 "- data corruption possible.\n", 4118 mdname(mddev)); 4119 else { 4120 printk(KERN_ERR 4121 "raid5: cannot start dirty degraded array for %s\n", 4122 mdname(mddev)); 4123 goto abort; 4124 } 4125 } 4126 4127 { 4128 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5"); 4129 if (!mddev->thread) { 4130 printk(KERN_ERR 4131 "raid5: couldn't allocate thread for %s\n", 4132 mdname(mddev)); 4133 goto abort; 4134 } 4135 } 4136 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + 4137 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; 4138 if (grow_stripes(conf, conf->max_nr_stripes)) { 4139 printk(KERN_ERR 4140 "raid5: couldn't allocate %dkB for buffers\n", memory); 4141 shrink_stripes(conf); 4142 md_unregister_thread(mddev->thread); 4143 goto abort; 4144 } else 4145 printk(KERN_INFO "raid5: allocated %dkB for %s\n", 4146 memory, mdname(mddev)); 4147 4148 if (mddev->degraded == 0) 4149 printk("raid5: raid level %d set %s active with %d out of %d" 4150 " devices, algorithm %d\n", conf->level, mdname(mddev), 4151 mddev->raid_disks-mddev->degraded, mddev->raid_disks, 4152 conf->algorithm); 4153 else 4154 printk(KERN_ALERT "raid5: raid level %d set %s active with %d" 4155 " out of %d devices, algorithm %d\n", conf->level, 4156 mdname(mddev), mddev->raid_disks - mddev->degraded, 4157 mddev->raid_disks, conf->algorithm); 4158 4159 print_raid5_conf(conf); 4160 4161 if (conf->expand_progress != MaxSector) { 4162 printk("...ok start reshape thread\n"); 4163 conf->expand_lo = conf->expand_progress; 4164 atomic_set(&conf->reshape_stripes, 0); 4165 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 4166 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 4167 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 4168 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 4169 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 4170 "%s_reshape"); 4171 } 4172 4173 /* read-ahead size must cover two whole stripes, which is 4174 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 4175 */ 4176 { 4177 int data_disks = conf->previous_raid_disks - conf->max_degraded; 4178 int stripe = data_disks * 4179 (mddev->chunk_size / PAGE_SIZE); 4180 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 4181 mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 4182 } 4183 4184 /* Ok, everything is just fine now */ 4185 if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group)) 4186 printk(KERN_WARNING 4187 "raid5: failed to create sysfs attributes for %s\n", 4188 mdname(mddev)); 4189 4190 mddev->queue->unplug_fn = raid5_unplug_device; 4191 mddev->queue->backing_dev_info.congested_data = mddev; 4192 mddev->queue->backing_dev_info.congested_fn = raid5_congested; 4193 4194 mddev->array_sectors = 2 * mddev->size * (conf->previous_raid_disks - 4195 conf->max_degraded); 4196 4197 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); 4198 4199 return 0; 4200 abort: 4201 if (conf) { 4202 print_raid5_conf(conf); 4203 safe_put_page(conf->spare_page); 4204 kfree(conf->disks); 4205 kfree(conf->stripe_hashtbl); 4206 kfree(conf); 4207 } 4208 mddev->private = NULL; 4209 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); 4210 return -EIO; 4211 } 4212 4213 4214 4215 static int stop(mddev_t *mddev) 4216 { 4217 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 4218 4219 md_unregister_thread(mddev->thread); 4220 mddev->thread = NULL; 4221 shrink_stripes(conf); 4222 kfree(conf->stripe_hashtbl); 4223 mddev->queue->backing_dev_info.congested_fn = NULL; 4224 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 4225 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group); 4226 kfree(conf->disks); 4227 kfree(conf); 4228 mddev->private = NULL; 4229 return 0; 4230 } 4231 4232 #ifdef DEBUG 4233 static void print_sh (struct seq_file *seq, struct stripe_head *sh) 4234 { 4235 int i; 4236 4237 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n", 4238 (unsigned long long)sh->sector, sh->pd_idx, sh->state); 4239 seq_printf(seq, "sh %llu, count %d.\n", 4240 (unsigned long long)sh->sector, atomic_read(&sh->count)); 4241 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector); 4242 for (i = 0; i < sh->disks; i++) { 4243 seq_printf(seq, "(cache%d: %p %ld) ", 4244 i, sh->dev[i].page, sh->dev[i].flags); 4245 } 4246 seq_printf(seq, "\n"); 4247 } 4248 4249 static void printall (struct seq_file *seq, raid5_conf_t *conf) 4250 { 4251 struct stripe_head *sh; 4252 struct hlist_node *hn; 4253 int i; 4254 4255 spin_lock_irq(&conf->device_lock); 4256 for (i = 0; i < NR_HASH; i++) { 4257 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) { 4258 if (sh->raid_conf != conf) 4259 continue; 4260 print_sh(seq, sh); 4261 } 4262 } 4263 spin_unlock_irq(&conf->device_lock); 4264 } 4265 #endif 4266 4267 static void status (struct seq_file *seq, mddev_t *mddev) 4268 { 4269 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 4270 int i; 4271 4272 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout); 4273 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); 4274 for (i = 0; i < conf->raid_disks; i++) 4275 seq_printf (seq, "%s", 4276 conf->disks[i].rdev && 4277 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_"); 4278 seq_printf (seq, "]"); 4279 #ifdef DEBUG 4280 seq_printf (seq, "\n"); 4281 printall(seq, conf); 4282 #endif 4283 } 4284 4285 static void print_raid5_conf (raid5_conf_t *conf) 4286 { 4287 int i; 4288 struct disk_info *tmp; 4289 4290 printk("RAID5 conf printout:\n"); 4291 if (!conf) { 4292 printk("(conf==NULL)\n"); 4293 return; 4294 } 4295 printk(" --- rd:%d wd:%d\n", conf->raid_disks, 4296 conf->raid_disks - conf->mddev->degraded); 4297 4298 for (i = 0; i < conf->raid_disks; i++) { 4299 char b[BDEVNAME_SIZE]; 4300 tmp = conf->disks + i; 4301 if (tmp->rdev) 4302 printk(" disk %d, o:%d, dev:%s\n", 4303 i, !test_bit(Faulty, &tmp->rdev->flags), 4304 bdevname(tmp->rdev->bdev,b)); 4305 } 4306 } 4307 4308 static int raid5_spare_active(mddev_t *mddev) 4309 { 4310 int i; 4311 raid5_conf_t *conf = mddev->private; 4312 struct disk_info *tmp; 4313 4314 for (i = 0; i < conf->raid_disks; i++) { 4315 tmp = conf->disks + i; 4316 if (tmp->rdev 4317 && !test_bit(Faulty, &tmp->rdev->flags) 4318 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 4319 unsigned long flags; 4320 spin_lock_irqsave(&conf->device_lock, flags); 4321 mddev->degraded--; 4322 spin_unlock_irqrestore(&conf->device_lock, flags); 4323 } 4324 } 4325 print_raid5_conf(conf); 4326 return 0; 4327 } 4328 4329 static int raid5_remove_disk(mddev_t *mddev, int number) 4330 { 4331 raid5_conf_t *conf = mddev->private; 4332 int err = 0; 4333 mdk_rdev_t *rdev; 4334 struct disk_info *p = conf->disks + number; 4335 4336 print_raid5_conf(conf); 4337 rdev = p->rdev; 4338 if (rdev) { 4339 if (test_bit(In_sync, &rdev->flags) || 4340 atomic_read(&rdev->nr_pending)) { 4341 err = -EBUSY; 4342 goto abort; 4343 } 4344 /* Only remove non-faulty devices if recovery 4345 * isn't possible. 4346 */ 4347 if (!test_bit(Faulty, &rdev->flags) && 4348 mddev->degraded <= conf->max_degraded) { 4349 err = -EBUSY; 4350 goto abort; 4351 } 4352 p->rdev = NULL; 4353 synchronize_rcu(); 4354 if (atomic_read(&rdev->nr_pending)) { 4355 /* lost the race, try later */ 4356 err = -EBUSY; 4357 p->rdev = rdev; 4358 } 4359 } 4360 abort: 4361 4362 print_raid5_conf(conf); 4363 return err; 4364 } 4365 4366 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 4367 { 4368 raid5_conf_t *conf = mddev->private; 4369 int err = -EEXIST; 4370 int disk; 4371 struct disk_info *p; 4372 int first = 0; 4373 int last = conf->raid_disks - 1; 4374 4375 if (mddev->degraded > conf->max_degraded) 4376 /* no point adding a device */ 4377 return -EINVAL; 4378 4379 if (rdev->raid_disk >= 0) 4380 first = last = rdev->raid_disk; 4381 4382 /* 4383 * find the disk ... but prefer rdev->saved_raid_disk 4384 * if possible. 4385 */ 4386 if (rdev->saved_raid_disk >= 0 && 4387 rdev->saved_raid_disk >= first && 4388 conf->disks[rdev->saved_raid_disk].rdev == NULL) 4389 disk = rdev->saved_raid_disk; 4390 else 4391 disk = first; 4392 for ( ; disk <= last ; disk++) 4393 if ((p=conf->disks + disk)->rdev == NULL) { 4394 clear_bit(In_sync, &rdev->flags); 4395 rdev->raid_disk = disk; 4396 err = 0; 4397 if (rdev->saved_raid_disk != disk) 4398 conf->fullsync = 1; 4399 rcu_assign_pointer(p->rdev, rdev); 4400 break; 4401 } 4402 print_raid5_conf(conf); 4403 return err; 4404 } 4405 4406 static int raid5_resize(mddev_t *mddev, sector_t sectors) 4407 { 4408 /* no resync is happening, and there is enough space 4409 * on all devices, so we can resize. 4410 * We need to make sure resync covers any new space. 4411 * If the array is shrinking we should possibly wait until 4412 * any io in the removed space completes, but it hardly seems 4413 * worth it. 4414 */ 4415 raid5_conf_t *conf = mddev_to_conf(mddev); 4416 4417 sectors &= ~((sector_t)mddev->chunk_size/512 - 1); 4418 mddev->array_sectors = sectors * (mddev->raid_disks 4419 - conf->max_degraded); 4420 set_capacity(mddev->gendisk, mddev->array_sectors); 4421 mddev->changed = 1; 4422 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) { 4423 mddev->recovery_cp = mddev->size << 1; 4424 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 4425 } 4426 mddev->size = sectors /2; 4427 mddev->resync_max_sectors = sectors; 4428 return 0; 4429 } 4430 4431 #ifdef CONFIG_MD_RAID5_RESHAPE 4432 static int raid5_check_reshape(mddev_t *mddev) 4433 { 4434 raid5_conf_t *conf = mddev_to_conf(mddev); 4435 int err; 4436 4437 if (mddev->delta_disks < 0 || 4438 mddev->new_level != mddev->level) 4439 return -EINVAL; /* Cannot shrink array or change level yet */ 4440 if (mddev->delta_disks == 0) 4441 return 0; /* nothing to do */ 4442 4443 /* Can only proceed if there are plenty of stripe_heads. 4444 * We need a minimum of one full stripe,, and for sensible progress 4445 * it is best to have about 4 times that. 4446 * If we require 4 times, then the default 256 4K stripe_heads will 4447 * allow for chunk sizes up to 256K, which is probably OK. 4448 * If the chunk size is greater, user-space should request more 4449 * stripe_heads first. 4450 */ 4451 if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes || 4452 (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) { 4453 printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n", 4454 (mddev->chunk_size / STRIPE_SIZE)*4); 4455 return -ENOSPC; 4456 } 4457 4458 err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks); 4459 if (err) 4460 return err; 4461 4462 if (mddev->degraded > conf->max_degraded) 4463 return -EINVAL; 4464 /* looks like we might be able to manage this */ 4465 return 0; 4466 } 4467 4468 static int raid5_start_reshape(mddev_t *mddev) 4469 { 4470 raid5_conf_t *conf = mddev_to_conf(mddev); 4471 mdk_rdev_t *rdev; 4472 struct list_head *rtmp; 4473 int spares = 0; 4474 int added_devices = 0; 4475 unsigned long flags; 4476 4477 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 4478 return -EBUSY; 4479 4480 rdev_for_each(rdev, rtmp, mddev) 4481 if (rdev->raid_disk < 0 && 4482 !test_bit(Faulty, &rdev->flags)) 4483 spares++; 4484 4485 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded) 4486 /* Not enough devices even to make a degraded array 4487 * of that size 4488 */ 4489 return -EINVAL; 4490 4491 atomic_set(&conf->reshape_stripes, 0); 4492 spin_lock_irq(&conf->device_lock); 4493 conf->previous_raid_disks = conf->raid_disks; 4494 conf->raid_disks += mddev->delta_disks; 4495 conf->expand_progress = 0; 4496 conf->expand_lo = 0; 4497 spin_unlock_irq(&conf->device_lock); 4498 4499 /* Add some new drives, as many as will fit. 4500 * We know there are enough to make the newly sized array work. 4501 */ 4502 rdev_for_each(rdev, rtmp, mddev) 4503 if (rdev->raid_disk < 0 && 4504 !test_bit(Faulty, &rdev->flags)) { 4505 if (raid5_add_disk(mddev, rdev) == 0) { 4506 char nm[20]; 4507 set_bit(In_sync, &rdev->flags); 4508 added_devices++; 4509 rdev->recovery_offset = 0; 4510 sprintf(nm, "rd%d", rdev->raid_disk); 4511 if (sysfs_create_link(&mddev->kobj, 4512 &rdev->kobj, nm)) 4513 printk(KERN_WARNING 4514 "raid5: failed to create " 4515 " link %s for %s\n", 4516 nm, mdname(mddev)); 4517 } else 4518 break; 4519 } 4520 4521 spin_lock_irqsave(&conf->device_lock, flags); 4522 mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices; 4523 spin_unlock_irqrestore(&conf->device_lock, flags); 4524 mddev->raid_disks = conf->raid_disks; 4525 mddev->reshape_position = 0; 4526 set_bit(MD_CHANGE_DEVS, &mddev->flags); 4527 4528 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 4529 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 4530 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 4531 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 4532 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 4533 "%s_reshape"); 4534 if (!mddev->sync_thread) { 4535 mddev->recovery = 0; 4536 spin_lock_irq(&conf->device_lock); 4537 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; 4538 conf->expand_progress = MaxSector; 4539 spin_unlock_irq(&conf->device_lock); 4540 return -EAGAIN; 4541 } 4542 md_wakeup_thread(mddev->sync_thread); 4543 md_new_event(mddev); 4544 return 0; 4545 } 4546 #endif 4547 4548 static void end_reshape(raid5_conf_t *conf) 4549 { 4550 struct block_device *bdev; 4551 4552 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) { 4553 conf->mddev->array_sectors = 2 * conf->mddev->size * 4554 (conf->raid_disks - conf->max_degraded); 4555 set_capacity(conf->mddev->gendisk, conf->mddev->array_sectors); 4556 conf->mddev->changed = 1; 4557 4558 bdev = bdget_disk(conf->mddev->gendisk, 0); 4559 if (bdev) { 4560 mutex_lock(&bdev->bd_inode->i_mutex); 4561 i_size_write(bdev->bd_inode, 4562 (loff_t)conf->mddev->array_sectors << 9); 4563 mutex_unlock(&bdev->bd_inode->i_mutex); 4564 bdput(bdev); 4565 } 4566 spin_lock_irq(&conf->device_lock); 4567 conf->expand_progress = MaxSector; 4568 spin_unlock_irq(&conf->device_lock); 4569 conf->mddev->reshape_position = MaxSector; 4570 4571 /* read-ahead size must cover two whole stripes, which is 4572 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 4573 */ 4574 { 4575 int data_disks = conf->previous_raid_disks - conf->max_degraded; 4576 int stripe = data_disks * 4577 (conf->mddev->chunk_size / PAGE_SIZE); 4578 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 4579 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 4580 } 4581 } 4582 } 4583 4584 static void raid5_quiesce(mddev_t *mddev, int state) 4585 { 4586 raid5_conf_t *conf = mddev_to_conf(mddev); 4587 4588 switch(state) { 4589 case 2: /* resume for a suspend */ 4590 wake_up(&conf->wait_for_overlap); 4591 break; 4592 4593 case 1: /* stop all writes */ 4594 spin_lock_irq(&conf->device_lock); 4595 conf->quiesce = 1; 4596 wait_event_lock_irq(conf->wait_for_stripe, 4597 atomic_read(&conf->active_stripes) == 0 && 4598 atomic_read(&conf->active_aligned_reads) == 0, 4599 conf->device_lock, /* nothing */); 4600 spin_unlock_irq(&conf->device_lock); 4601 break; 4602 4603 case 0: /* re-enable writes */ 4604 spin_lock_irq(&conf->device_lock); 4605 conf->quiesce = 0; 4606 wake_up(&conf->wait_for_stripe); 4607 wake_up(&conf->wait_for_overlap); 4608 spin_unlock_irq(&conf->device_lock); 4609 break; 4610 } 4611 } 4612 4613 static struct mdk_personality raid6_personality = 4614 { 4615 .name = "raid6", 4616 .level = 6, 4617 .owner = THIS_MODULE, 4618 .make_request = make_request, 4619 .run = run, 4620 .stop = stop, 4621 .status = status, 4622 .error_handler = error, 4623 .hot_add_disk = raid5_add_disk, 4624 .hot_remove_disk= raid5_remove_disk, 4625 .spare_active = raid5_spare_active, 4626 .sync_request = sync_request, 4627 .resize = raid5_resize, 4628 #ifdef CONFIG_MD_RAID5_RESHAPE 4629 .check_reshape = raid5_check_reshape, 4630 .start_reshape = raid5_start_reshape, 4631 #endif 4632 .quiesce = raid5_quiesce, 4633 }; 4634 static struct mdk_personality raid5_personality = 4635 { 4636 .name = "raid5", 4637 .level = 5, 4638 .owner = THIS_MODULE, 4639 .make_request = make_request, 4640 .run = run, 4641 .stop = stop, 4642 .status = status, 4643 .error_handler = error, 4644 .hot_add_disk = raid5_add_disk, 4645 .hot_remove_disk= raid5_remove_disk, 4646 .spare_active = raid5_spare_active, 4647 .sync_request = sync_request, 4648 .resize = raid5_resize, 4649 #ifdef CONFIG_MD_RAID5_RESHAPE 4650 .check_reshape = raid5_check_reshape, 4651 .start_reshape = raid5_start_reshape, 4652 #endif 4653 .quiesce = raid5_quiesce, 4654 }; 4655 4656 static struct mdk_personality raid4_personality = 4657 { 4658 .name = "raid4", 4659 .level = 4, 4660 .owner = THIS_MODULE, 4661 .make_request = make_request, 4662 .run = run, 4663 .stop = stop, 4664 .status = status, 4665 .error_handler = error, 4666 .hot_add_disk = raid5_add_disk, 4667 .hot_remove_disk= raid5_remove_disk, 4668 .spare_active = raid5_spare_active, 4669 .sync_request = sync_request, 4670 .resize = raid5_resize, 4671 #ifdef CONFIG_MD_RAID5_RESHAPE 4672 .check_reshape = raid5_check_reshape, 4673 .start_reshape = raid5_start_reshape, 4674 #endif 4675 .quiesce = raid5_quiesce, 4676 }; 4677 4678 static int __init raid5_init(void) 4679 { 4680 int e; 4681 4682 e = raid6_select_algo(); 4683 if ( e ) 4684 return e; 4685 register_md_personality(&raid6_personality); 4686 register_md_personality(&raid5_personality); 4687 register_md_personality(&raid4_personality); 4688 return 0; 4689 } 4690 4691 static void raid5_exit(void) 4692 { 4693 unregister_md_personality(&raid6_personality); 4694 unregister_md_personality(&raid5_personality); 4695 unregister_md_personality(&raid4_personality); 4696 } 4697 4698 module_init(raid5_init); 4699 module_exit(raid5_exit); 4700 MODULE_LICENSE("GPL"); 4701 MODULE_ALIAS("md-personality-4"); /* RAID5 */ 4702 MODULE_ALIAS("md-raid5"); 4703 MODULE_ALIAS("md-raid4"); 4704 MODULE_ALIAS("md-level-5"); 4705 MODULE_ALIAS("md-level-4"); 4706 MODULE_ALIAS("md-personality-8"); /* RAID6 */ 4707 MODULE_ALIAS("md-raid6"); 4708 MODULE_ALIAS("md-level-6"); 4709 4710 /* This used to be two separate modules, they were: */ 4711 MODULE_ALIAS("raid5"); 4712 MODULE_ALIAS("raid6"); 4713