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/blkdev.h> 47 #include <linux/kthread.h> 48 #include <linux/raid/pq.h> 49 #include <linux/async_tx.h> 50 #include <linux/async.h> 51 #include <linux/seq_file.h> 52 #include <linux/cpu.h> 53 #include "md.h" 54 #include "raid5.h" 55 #include "bitmap.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 /* 100 * We maintain a biased count of active stripes in the bottom 16 bits of 101 * bi_phys_segments, and a count of processed stripes in the upper 16 bits 102 */ 103 static inline int raid5_bi_phys_segments(struct bio *bio) 104 { 105 return bio->bi_phys_segments & 0xffff; 106 } 107 108 static inline int raid5_bi_hw_segments(struct bio *bio) 109 { 110 return (bio->bi_phys_segments >> 16) & 0xffff; 111 } 112 113 static inline int raid5_dec_bi_phys_segments(struct bio *bio) 114 { 115 --bio->bi_phys_segments; 116 return raid5_bi_phys_segments(bio); 117 } 118 119 static inline int raid5_dec_bi_hw_segments(struct bio *bio) 120 { 121 unsigned short val = raid5_bi_hw_segments(bio); 122 123 --val; 124 bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio); 125 return val; 126 } 127 128 static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt) 129 { 130 bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16); 131 } 132 133 /* Find first data disk in a raid6 stripe */ 134 static inline int raid6_d0(struct stripe_head *sh) 135 { 136 if (sh->ddf_layout) 137 /* ddf always start from first device */ 138 return 0; 139 /* md starts just after Q block */ 140 if (sh->qd_idx == sh->disks - 1) 141 return 0; 142 else 143 return sh->qd_idx + 1; 144 } 145 static inline int raid6_next_disk(int disk, int raid_disks) 146 { 147 disk++; 148 return (disk < raid_disks) ? disk : 0; 149 } 150 151 /* When walking through the disks in a raid5, starting at raid6_d0, 152 * We need to map each disk to a 'slot', where the data disks are slot 153 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk 154 * is raid_disks-1. This help does that mapping. 155 */ 156 static int raid6_idx_to_slot(int idx, struct stripe_head *sh, 157 int *count, int syndrome_disks) 158 { 159 int slot = *count; 160 161 if (sh->ddf_layout) 162 (*count)++; 163 if (idx == sh->pd_idx) 164 return syndrome_disks; 165 if (idx == sh->qd_idx) 166 return syndrome_disks + 1; 167 if (!sh->ddf_layout) 168 (*count)++; 169 return slot; 170 } 171 172 static void return_io(struct bio *return_bi) 173 { 174 struct bio *bi = return_bi; 175 while (bi) { 176 177 return_bi = bi->bi_next; 178 bi->bi_next = NULL; 179 bi->bi_size = 0; 180 bio_endio(bi, 0); 181 bi = return_bi; 182 } 183 } 184 185 static void print_raid5_conf (raid5_conf_t *conf); 186 187 static int stripe_operations_active(struct stripe_head *sh) 188 { 189 return sh->check_state || sh->reconstruct_state || 190 test_bit(STRIPE_BIOFILL_RUN, &sh->state) || 191 test_bit(STRIPE_COMPUTE_RUN, &sh->state); 192 } 193 194 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) 195 { 196 if (atomic_dec_and_test(&sh->count)) { 197 BUG_ON(!list_empty(&sh->lru)); 198 BUG_ON(atomic_read(&conf->active_stripes)==0); 199 if (test_bit(STRIPE_HANDLE, &sh->state)) { 200 if (test_bit(STRIPE_DELAYED, &sh->state)) { 201 list_add_tail(&sh->lru, &conf->delayed_list); 202 blk_plug_device(conf->mddev->queue); 203 } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && 204 sh->bm_seq - conf->seq_write > 0) { 205 list_add_tail(&sh->lru, &conf->bitmap_list); 206 blk_plug_device(conf->mddev->queue); 207 } else { 208 clear_bit(STRIPE_BIT_DELAY, &sh->state); 209 list_add_tail(&sh->lru, &conf->handle_list); 210 } 211 md_wakeup_thread(conf->mddev->thread); 212 } else { 213 BUG_ON(stripe_operations_active(sh)); 214 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 215 atomic_dec(&conf->preread_active_stripes); 216 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 217 md_wakeup_thread(conf->mddev->thread); 218 } 219 atomic_dec(&conf->active_stripes); 220 if (!test_bit(STRIPE_EXPANDING, &sh->state)) { 221 list_add_tail(&sh->lru, &conf->inactive_list); 222 wake_up(&conf->wait_for_stripe); 223 if (conf->retry_read_aligned) 224 md_wakeup_thread(conf->mddev->thread); 225 } 226 } 227 } 228 } 229 230 static void release_stripe(struct stripe_head *sh) 231 { 232 raid5_conf_t *conf = sh->raid_conf; 233 unsigned long flags; 234 235 spin_lock_irqsave(&conf->device_lock, flags); 236 __release_stripe(conf, sh); 237 spin_unlock_irqrestore(&conf->device_lock, flags); 238 } 239 240 static inline void remove_hash(struct stripe_head *sh) 241 { 242 pr_debug("remove_hash(), stripe %llu\n", 243 (unsigned long long)sh->sector); 244 245 hlist_del_init(&sh->hash); 246 } 247 248 static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) 249 { 250 struct hlist_head *hp = stripe_hash(conf, sh->sector); 251 252 pr_debug("insert_hash(), stripe %llu\n", 253 (unsigned long long)sh->sector); 254 255 CHECK_DEVLOCK(); 256 hlist_add_head(&sh->hash, hp); 257 } 258 259 260 /* find an idle stripe, make sure it is unhashed, and return it. */ 261 static struct stripe_head *get_free_stripe(raid5_conf_t *conf) 262 { 263 struct stripe_head *sh = NULL; 264 struct list_head *first; 265 266 CHECK_DEVLOCK(); 267 if (list_empty(&conf->inactive_list)) 268 goto out; 269 first = conf->inactive_list.next; 270 sh = list_entry(first, struct stripe_head, lru); 271 list_del_init(first); 272 remove_hash(sh); 273 atomic_inc(&conf->active_stripes); 274 out: 275 return sh; 276 } 277 278 static void shrink_buffers(struct stripe_head *sh, int num) 279 { 280 struct page *p; 281 int i; 282 283 for (i=0; i<num ; i++) { 284 p = sh->dev[i].page; 285 if (!p) 286 continue; 287 sh->dev[i].page = NULL; 288 put_page(p); 289 } 290 } 291 292 static int grow_buffers(struct stripe_head *sh, int num) 293 { 294 int i; 295 296 for (i=0; i<num; i++) { 297 struct page *page; 298 299 if (!(page = alloc_page(GFP_KERNEL))) { 300 return 1; 301 } 302 sh->dev[i].page = page; 303 } 304 return 0; 305 } 306 307 static void raid5_build_block(struct stripe_head *sh, int i, int previous); 308 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous, 309 struct stripe_head *sh); 310 311 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) 312 { 313 raid5_conf_t *conf = sh->raid_conf; 314 int i; 315 316 BUG_ON(atomic_read(&sh->count) != 0); 317 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); 318 BUG_ON(stripe_operations_active(sh)); 319 320 CHECK_DEVLOCK(); 321 pr_debug("init_stripe called, stripe %llu\n", 322 (unsigned long long)sh->sector); 323 324 remove_hash(sh); 325 326 sh->generation = conf->generation - previous; 327 sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks; 328 sh->sector = sector; 329 stripe_set_idx(sector, conf, previous, sh); 330 sh->state = 0; 331 332 333 for (i = sh->disks; i--; ) { 334 struct r5dev *dev = &sh->dev[i]; 335 336 if (dev->toread || dev->read || dev->towrite || dev->written || 337 test_bit(R5_LOCKED, &dev->flags)) { 338 printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n", 339 (unsigned long long)sh->sector, i, dev->toread, 340 dev->read, dev->towrite, dev->written, 341 test_bit(R5_LOCKED, &dev->flags)); 342 BUG(); 343 } 344 dev->flags = 0; 345 raid5_build_block(sh, i, previous); 346 } 347 insert_hash(conf, sh); 348 } 349 350 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, 351 short generation) 352 { 353 struct stripe_head *sh; 354 struct hlist_node *hn; 355 356 CHECK_DEVLOCK(); 357 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector); 358 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash) 359 if (sh->sector == sector && sh->generation == generation) 360 return sh; 361 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector); 362 return NULL; 363 } 364 365 static void unplug_slaves(mddev_t *mddev); 366 static void raid5_unplug_device(struct request_queue *q); 367 368 static struct stripe_head * 369 get_active_stripe(raid5_conf_t *conf, sector_t sector, 370 int previous, int noblock, int noquiesce) 371 { 372 struct stripe_head *sh; 373 374 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector); 375 376 spin_lock_irq(&conf->device_lock); 377 378 do { 379 wait_event_lock_irq(conf->wait_for_stripe, 380 conf->quiesce == 0 || noquiesce, 381 conf->device_lock, /* nothing */); 382 sh = __find_stripe(conf, sector, conf->generation - previous); 383 if (!sh) { 384 if (!conf->inactive_blocked) 385 sh = get_free_stripe(conf); 386 if (noblock && sh == NULL) 387 break; 388 if (!sh) { 389 conf->inactive_blocked = 1; 390 wait_event_lock_irq(conf->wait_for_stripe, 391 !list_empty(&conf->inactive_list) && 392 (atomic_read(&conf->active_stripes) 393 < (conf->max_nr_stripes *3/4) 394 || !conf->inactive_blocked), 395 conf->device_lock, 396 raid5_unplug_device(conf->mddev->queue) 397 ); 398 conf->inactive_blocked = 0; 399 } else 400 init_stripe(sh, sector, previous); 401 } else { 402 if (atomic_read(&sh->count)) { 403 BUG_ON(!list_empty(&sh->lru) 404 && !test_bit(STRIPE_EXPANDING, &sh->state)); 405 } else { 406 if (!test_bit(STRIPE_HANDLE, &sh->state)) 407 atomic_inc(&conf->active_stripes); 408 if (list_empty(&sh->lru) && 409 !test_bit(STRIPE_EXPANDING, &sh->state)) 410 BUG(); 411 list_del_init(&sh->lru); 412 } 413 } 414 } while (sh == NULL); 415 416 if (sh) 417 atomic_inc(&sh->count); 418 419 spin_unlock_irq(&conf->device_lock); 420 return sh; 421 } 422 423 static void 424 raid5_end_read_request(struct bio *bi, int error); 425 static void 426 raid5_end_write_request(struct bio *bi, int error); 427 428 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 429 { 430 raid5_conf_t *conf = sh->raid_conf; 431 int i, disks = sh->disks; 432 433 might_sleep(); 434 435 for (i = disks; i--; ) { 436 int rw; 437 struct bio *bi; 438 mdk_rdev_t *rdev; 439 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 440 rw = WRITE; 441 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 442 rw = READ; 443 else 444 continue; 445 446 bi = &sh->dev[i].req; 447 448 bi->bi_rw = rw; 449 if (rw == WRITE) 450 bi->bi_end_io = raid5_end_write_request; 451 else 452 bi->bi_end_io = raid5_end_read_request; 453 454 rcu_read_lock(); 455 rdev = rcu_dereference(conf->disks[i].rdev); 456 if (rdev && test_bit(Faulty, &rdev->flags)) 457 rdev = NULL; 458 if (rdev) 459 atomic_inc(&rdev->nr_pending); 460 rcu_read_unlock(); 461 462 if (rdev) { 463 if (s->syncing || s->expanding || s->expanded) 464 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 465 466 set_bit(STRIPE_IO_STARTED, &sh->state); 467 468 bi->bi_bdev = rdev->bdev; 469 pr_debug("%s: for %llu schedule op %ld on disc %d\n", 470 __func__, (unsigned long long)sh->sector, 471 bi->bi_rw, i); 472 atomic_inc(&sh->count); 473 bi->bi_sector = sh->sector + rdev->data_offset; 474 bi->bi_flags = 1 << BIO_UPTODATE; 475 bi->bi_vcnt = 1; 476 bi->bi_max_vecs = 1; 477 bi->bi_idx = 0; 478 bi->bi_io_vec = &sh->dev[i].vec; 479 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 480 bi->bi_io_vec[0].bv_offset = 0; 481 bi->bi_size = STRIPE_SIZE; 482 bi->bi_next = NULL; 483 if (rw == WRITE && 484 test_bit(R5_ReWrite, &sh->dev[i].flags)) 485 atomic_add(STRIPE_SECTORS, 486 &rdev->corrected_errors); 487 generic_make_request(bi); 488 } else { 489 if (rw == WRITE) 490 set_bit(STRIPE_DEGRADED, &sh->state); 491 pr_debug("skip op %ld on disc %d for sector %llu\n", 492 bi->bi_rw, i, (unsigned long long)sh->sector); 493 clear_bit(R5_LOCKED, &sh->dev[i].flags); 494 set_bit(STRIPE_HANDLE, &sh->state); 495 } 496 } 497 } 498 499 static struct dma_async_tx_descriptor * 500 async_copy_data(int frombio, struct bio *bio, struct page *page, 501 sector_t sector, struct dma_async_tx_descriptor *tx) 502 { 503 struct bio_vec *bvl; 504 struct page *bio_page; 505 int i; 506 int page_offset; 507 struct async_submit_ctl submit; 508 enum async_tx_flags flags = 0; 509 510 if (bio->bi_sector >= sector) 511 page_offset = (signed)(bio->bi_sector - sector) * 512; 512 else 513 page_offset = (signed)(sector - bio->bi_sector) * -512; 514 515 if (frombio) 516 flags |= ASYNC_TX_FENCE; 517 init_async_submit(&submit, flags, tx, NULL, NULL, NULL); 518 519 bio_for_each_segment(bvl, bio, i) { 520 int len = bio_iovec_idx(bio, i)->bv_len; 521 int clen; 522 int b_offset = 0; 523 524 if (page_offset < 0) { 525 b_offset = -page_offset; 526 page_offset += b_offset; 527 len -= b_offset; 528 } 529 530 if (len > 0 && page_offset + len > STRIPE_SIZE) 531 clen = STRIPE_SIZE - page_offset; 532 else 533 clen = len; 534 535 if (clen > 0) { 536 b_offset += bio_iovec_idx(bio, i)->bv_offset; 537 bio_page = bio_iovec_idx(bio, i)->bv_page; 538 if (frombio) 539 tx = async_memcpy(page, bio_page, page_offset, 540 b_offset, clen, &submit); 541 else 542 tx = async_memcpy(bio_page, page, b_offset, 543 page_offset, clen, &submit); 544 } 545 /* chain the operations */ 546 submit.depend_tx = tx; 547 548 if (clen < len) /* hit end of page */ 549 break; 550 page_offset += len; 551 } 552 553 return tx; 554 } 555 556 static void ops_complete_biofill(void *stripe_head_ref) 557 { 558 struct stripe_head *sh = stripe_head_ref; 559 struct bio *return_bi = NULL; 560 raid5_conf_t *conf = sh->raid_conf; 561 int i; 562 563 pr_debug("%s: stripe %llu\n", __func__, 564 (unsigned long long)sh->sector); 565 566 /* clear completed biofills */ 567 spin_lock_irq(&conf->device_lock); 568 for (i = sh->disks; i--; ) { 569 struct r5dev *dev = &sh->dev[i]; 570 571 /* acknowledge completion of a biofill operation */ 572 /* and check if we need to reply to a read request, 573 * new R5_Wantfill requests are held off until 574 * !STRIPE_BIOFILL_RUN 575 */ 576 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) { 577 struct bio *rbi, *rbi2; 578 579 BUG_ON(!dev->read); 580 rbi = dev->read; 581 dev->read = NULL; 582 while (rbi && rbi->bi_sector < 583 dev->sector + STRIPE_SECTORS) { 584 rbi2 = r5_next_bio(rbi, dev->sector); 585 if (!raid5_dec_bi_phys_segments(rbi)) { 586 rbi->bi_next = return_bi; 587 return_bi = rbi; 588 } 589 rbi = rbi2; 590 } 591 } 592 } 593 spin_unlock_irq(&conf->device_lock); 594 clear_bit(STRIPE_BIOFILL_RUN, &sh->state); 595 596 return_io(return_bi); 597 598 set_bit(STRIPE_HANDLE, &sh->state); 599 release_stripe(sh); 600 } 601 602 static void ops_run_biofill(struct stripe_head *sh) 603 { 604 struct dma_async_tx_descriptor *tx = NULL; 605 raid5_conf_t *conf = sh->raid_conf; 606 struct async_submit_ctl submit; 607 int i; 608 609 pr_debug("%s: stripe %llu\n", __func__, 610 (unsigned long long)sh->sector); 611 612 for (i = sh->disks; i--; ) { 613 struct r5dev *dev = &sh->dev[i]; 614 if (test_bit(R5_Wantfill, &dev->flags)) { 615 struct bio *rbi; 616 spin_lock_irq(&conf->device_lock); 617 dev->read = rbi = dev->toread; 618 dev->toread = NULL; 619 spin_unlock_irq(&conf->device_lock); 620 while (rbi && rbi->bi_sector < 621 dev->sector + STRIPE_SECTORS) { 622 tx = async_copy_data(0, rbi, dev->page, 623 dev->sector, tx); 624 rbi = r5_next_bio(rbi, dev->sector); 625 } 626 } 627 } 628 629 atomic_inc(&sh->count); 630 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL); 631 async_trigger_callback(&submit); 632 } 633 634 static void mark_target_uptodate(struct stripe_head *sh, int target) 635 { 636 struct r5dev *tgt; 637 638 if (target < 0) 639 return; 640 641 tgt = &sh->dev[target]; 642 set_bit(R5_UPTODATE, &tgt->flags); 643 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 644 clear_bit(R5_Wantcompute, &tgt->flags); 645 } 646 647 static void ops_complete_compute(void *stripe_head_ref) 648 { 649 struct stripe_head *sh = stripe_head_ref; 650 651 pr_debug("%s: stripe %llu\n", __func__, 652 (unsigned long long)sh->sector); 653 654 /* mark the computed target(s) as uptodate */ 655 mark_target_uptodate(sh, sh->ops.target); 656 mark_target_uptodate(sh, sh->ops.target2); 657 658 clear_bit(STRIPE_COMPUTE_RUN, &sh->state); 659 if (sh->check_state == check_state_compute_run) 660 sh->check_state = check_state_compute_result; 661 set_bit(STRIPE_HANDLE, &sh->state); 662 release_stripe(sh); 663 } 664 665 /* return a pointer to the address conversion region of the scribble buffer */ 666 static addr_conv_t *to_addr_conv(struct stripe_head *sh, 667 struct raid5_percpu *percpu) 668 { 669 return percpu->scribble + sizeof(struct page *) * (sh->disks + 2); 670 } 671 672 static struct dma_async_tx_descriptor * 673 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu) 674 { 675 int disks = sh->disks; 676 struct page **xor_srcs = percpu->scribble; 677 int target = sh->ops.target; 678 struct r5dev *tgt = &sh->dev[target]; 679 struct page *xor_dest = tgt->page; 680 int count = 0; 681 struct dma_async_tx_descriptor *tx; 682 struct async_submit_ctl submit; 683 int i; 684 685 pr_debug("%s: stripe %llu block: %d\n", 686 __func__, (unsigned long long)sh->sector, target); 687 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 688 689 for (i = disks; i--; ) 690 if (i != target) 691 xor_srcs[count++] = sh->dev[i].page; 692 693 atomic_inc(&sh->count); 694 695 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL, 696 ops_complete_compute, sh, to_addr_conv(sh, percpu)); 697 if (unlikely(count == 1)) 698 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit); 699 else 700 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit); 701 702 return tx; 703 } 704 705 /* set_syndrome_sources - populate source buffers for gen_syndrome 706 * @srcs - (struct page *) array of size sh->disks 707 * @sh - stripe_head to parse 708 * 709 * Populates srcs in proper layout order for the stripe and returns the 710 * 'count' of sources to be used in a call to async_gen_syndrome. The P 711 * destination buffer is recorded in srcs[count] and the Q destination 712 * is recorded in srcs[count+1]]. 713 */ 714 static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh) 715 { 716 int disks = sh->disks; 717 int syndrome_disks = sh->ddf_layout ? disks : (disks - 2); 718 int d0_idx = raid6_d0(sh); 719 int count; 720 int i; 721 722 for (i = 0; i < disks; i++) 723 srcs[i] = NULL; 724 725 count = 0; 726 i = d0_idx; 727 do { 728 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks); 729 730 srcs[slot] = sh->dev[i].page; 731 i = raid6_next_disk(i, disks); 732 } while (i != d0_idx); 733 734 return syndrome_disks; 735 } 736 737 static struct dma_async_tx_descriptor * 738 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu) 739 { 740 int disks = sh->disks; 741 struct page **blocks = percpu->scribble; 742 int target; 743 int qd_idx = sh->qd_idx; 744 struct dma_async_tx_descriptor *tx; 745 struct async_submit_ctl submit; 746 struct r5dev *tgt; 747 struct page *dest; 748 int i; 749 int count; 750 751 if (sh->ops.target < 0) 752 target = sh->ops.target2; 753 else if (sh->ops.target2 < 0) 754 target = sh->ops.target; 755 else 756 /* we should only have one valid target */ 757 BUG(); 758 BUG_ON(target < 0); 759 pr_debug("%s: stripe %llu block: %d\n", 760 __func__, (unsigned long long)sh->sector, target); 761 762 tgt = &sh->dev[target]; 763 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 764 dest = tgt->page; 765 766 atomic_inc(&sh->count); 767 768 if (target == qd_idx) { 769 count = set_syndrome_sources(blocks, sh); 770 blocks[count] = NULL; /* regenerating p is not necessary */ 771 BUG_ON(blocks[count+1] != dest); /* q should already be set */ 772 init_async_submit(&submit, ASYNC_TX_FENCE, NULL, 773 ops_complete_compute, sh, 774 to_addr_conv(sh, percpu)); 775 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit); 776 } else { 777 /* Compute any data- or p-drive using XOR */ 778 count = 0; 779 for (i = disks; i-- ; ) { 780 if (i == target || i == qd_idx) 781 continue; 782 blocks[count++] = sh->dev[i].page; 783 } 784 785 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, 786 NULL, ops_complete_compute, sh, 787 to_addr_conv(sh, percpu)); 788 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit); 789 } 790 791 return tx; 792 } 793 794 static struct dma_async_tx_descriptor * 795 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu) 796 { 797 int i, count, disks = sh->disks; 798 int syndrome_disks = sh->ddf_layout ? disks : disks-2; 799 int d0_idx = raid6_d0(sh); 800 int faila = -1, failb = -1; 801 int target = sh->ops.target; 802 int target2 = sh->ops.target2; 803 struct r5dev *tgt = &sh->dev[target]; 804 struct r5dev *tgt2 = &sh->dev[target2]; 805 struct dma_async_tx_descriptor *tx; 806 struct page **blocks = percpu->scribble; 807 struct async_submit_ctl submit; 808 809 pr_debug("%s: stripe %llu block1: %d block2: %d\n", 810 __func__, (unsigned long long)sh->sector, target, target2); 811 BUG_ON(target < 0 || target2 < 0); 812 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 813 BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags)); 814 815 /* we need to open-code set_syndrome_sources to handle the 816 * slot number conversion for 'faila' and 'failb' 817 */ 818 for (i = 0; i < disks ; i++) 819 blocks[i] = NULL; 820 count = 0; 821 i = d0_idx; 822 do { 823 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks); 824 825 blocks[slot] = sh->dev[i].page; 826 827 if (i == target) 828 faila = slot; 829 if (i == target2) 830 failb = slot; 831 i = raid6_next_disk(i, disks); 832 } while (i != d0_idx); 833 834 BUG_ON(faila == failb); 835 if (failb < faila) 836 swap(faila, failb); 837 pr_debug("%s: stripe: %llu faila: %d failb: %d\n", 838 __func__, (unsigned long long)sh->sector, faila, failb); 839 840 atomic_inc(&sh->count); 841 842 if (failb == syndrome_disks+1) { 843 /* Q disk is one of the missing disks */ 844 if (faila == syndrome_disks) { 845 /* Missing P+Q, just recompute */ 846 init_async_submit(&submit, ASYNC_TX_FENCE, NULL, 847 ops_complete_compute, sh, 848 to_addr_conv(sh, percpu)); 849 return async_gen_syndrome(blocks, 0, syndrome_disks+2, 850 STRIPE_SIZE, &submit); 851 } else { 852 struct page *dest; 853 int data_target; 854 int qd_idx = sh->qd_idx; 855 856 /* Missing D+Q: recompute D from P, then recompute Q */ 857 if (target == qd_idx) 858 data_target = target2; 859 else 860 data_target = target; 861 862 count = 0; 863 for (i = disks; i-- ; ) { 864 if (i == data_target || i == qd_idx) 865 continue; 866 blocks[count++] = sh->dev[i].page; 867 } 868 dest = sh->dev[data_target].page; 869 init_async_submit(&submit, 870 ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, 871 NULL, NULL, NULL, 872 to_addr_conv(sh, percpu)); 873 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, 874 &submit); 875 876 count = set_syndrome_sources(blocks, sh); 877 init_async_submit(&submit, ASYNC_TX_FENCE, tx, 878 ops_complete_compute, sh, 879 to_addr_conv(sh, percpu)); 880 return async_gen_syndrome(blocks, 0, count+2, 881 STRIPE_SIZE, &submit); 882 } 883 } else { 884 init_async_submit(&submit, ASYNC_TX_FENCE, NULL, 885 ops_complete_compute, sh, 886 to_addr_conv(sh, percpu)); 887 if (failb == syndrome_disks) { 888 /* We're missing D+P. */ 889 return async_raid6_datap_recov(syndrome_disks+2, 890 STRIPE_SIZE, faila, 891 blocks, &submit); 892 } else { 893 /* We're missing D+D. */ 894 return async_raid6_2data_recov(syndrome_disks+2, 895 STRIPE_SIZE, faila, failb, 896 blocks, &submit); 897 } 898 } 899 } 900 901 902 static void ops_complete_prexor(void *stripe_head_ref) 903 { 904 struct stripe_head *sh = stripe_head_ref; 905 906 pr_debug("%s: stripe %llu\n", __func__, 907 (unsigned long long)sh->sector); 908 } 909 910 static struct dma_async_tx_descriptor * 911 ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu, 912 struct dma_async_tx_descriptor *tx) 913 { 914 int disks = sh->disks; 915 struct page **xor_srcs = percpu->scribble; 916 int count = 0, pd_idx = sh->pd_idx, i; 917 struct async_submit_ctl submit; 918 919 /* existing parity data subtracted */ 920 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 921 922 pr_debug("%s: stripe %llu\n", __func__, 923 (unsigned long long)sh->sector); 924 925 for (i = disks; i--; ) { 926 struct r5dev *dev = &sh->dev[i]; 927 /* Only process blocks that are known to be uptodate */ 928 if (test_bit(R5_Wantdrain, &dev->flags)) 929 xor_srcs[count++] = dev->page; 930 } 931 932 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, 933 ops_complete_prexor, sh, to_addr_conv(sh, percpu)); 934 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit); 935 936 return tx; 937 } 938 939 static struct dma_async_tx_descriptor * 940 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) 941 { 942 int disks = sh->disks; 943 int i; 944 945 pr_debug("%s: stripe %llu\n", __func__, 946 (unsigned long long)sh->sector); 947 948 for (i = disks; i--; ) { 949 struct r5dev *dev = &sh->dev[i]; 950 struct bio *chosen; 951 952 if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) { 953 struct bio *wbi; 954 955 spin_lock(&sh->lock); 956 chosen = dev->towrite; 957 dev->towrite = NULL; 958 BUG_ON(dev->written); 959 wbi = dev->written = chosen; 960 spin_unlock(&sh->lock); 961 962 while (wbi && wbi->bi_sector < 963 dev->sector + STRIPE_SECTORS) { 964 tx = async_copy_data(1, wbi, dev->page, 965 dev->sector, tx); 966 wbi = r5_next_bio(wbi, dev->sector); 967 } 968 } 969 } 970 971 return tx; 972 } 973 974 static void ops_complete_reconstruct(void *stripe_head_ref) 975 { 976 struct stripe_head *sh = stripe_head_ref; 977 int disks = sh->disks; 978 int pd_idx = sh->pd_idx; 979 int qd_idx = sh->qd_idx; 980 int i; 981 982 pr_debug("%s: stripe %llu\n", __func__, 983 (unsigned long long)sh->sector); 984 985 for (i = disks; i--; ) { 986 struct r5dev *dev = &sh->dev[i]; 987 988 if (dev->written || i == pd_idx || i == qd_idx) 989 set_bit(R5_UPTODATE, &dev->flags); 990 } 991 992 if (sh->reconstruct_state == reconstruct_state_drain_run) 993 sh->reconstruct_state = reconstruct_state_drain_result; 994 else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) 995 sh->reconstruct_state = reconstruct_state_prexor_drain_result; 996 else { 997 BUG_ON(sh->reconstruct_state != reconstruct_state_run); 998 sh->reconstruct_state = reconstruct_state_result; 999 } 1000 1001 set_bit(STRIPE_HANDLE, &sh->state); 1002 release_stripe(sh); 1003 } 1004 1005 static void 1006 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu, 1007 struct dma_async_tx_descriptor *tx) 1008 { 1009 int disks = sh->disks; 1010 struct page **xor_srcs = percpu->scribble; 1011 struct async_submit_ctl submit; 1012 int count = 0, pd_idx = sh->pd_idx, i; 1013 struct page *xor_dest; 1014 int prexor = 0; 1015 unsigned long flags; 1016 1017 pr_debug("%s: stripe %llu\n", __func__, 1018 (unsigned long long)sh->sector); 1019 1020 /* check if prexor is active which means only process blocks 1021 * that are part of a read-modify-write (written) 1022 */ 1023 if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) { 1024 prexor = 1; 1025 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 1026 for (i = disks; i--; ) { 1027 struct r5dev *dev = &sh->dev[i]; 1028 if (dev->written) 1029 xor_srcs[count++] = dev->page; 1030 } 1031 } else { 1032 xor_dest = sh->dev[pd_idx].page; 1033 for (i = disks; i--; ) { 1034 struct r5dev *dev = &sh->dev[i]; 1035 if (i != pd_idx) 1036 xor_srcs[count++] = dev->page; 1037 } 1038 } 1039 1040 /* 1/ if we prexor'd then the dest is reused as a source 1041 * 2/ if we did not prexor then we are redoing the parity 1042 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST 1043 * for the synchronous xor case 1044 */ 1045 flags = ASYNC_TX_ACK | 1046 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST); 1047 1048 atomic_inc(&sh->count); 1049 1050 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh, 1051 to_addr_conv(sh, percpu)); 1052 if (unlikely(count == 1)) 1053 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit); 1054 else 1055 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit); 1056 } 1057 1058 static void 1059 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu, 1060 struct dma_async_tx_descriptor *tx) 1061 { 1062 struct async_submit_ctl submit; 1063 struct page **blocks = percpu->scribble; 1064 int count; 1065 1066 pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); 1067 1068 count = set_syndrome_sources(blocks, sh); 1069 1070 atomic_inc(&sh->count); 1071 1072 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct, 1073 sh, to_addr_conv(sh, percpu)); 1074 async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit); 1075 } 1076 1077 static void ops_complete_check(void *stripe_head_ref) 1078 { 1079 struct stripe_head *sh = stripe_head_ref; 1080 1081 pr_debug("%s: stripe %llu\n", __func__, 1082 (unsigned long long)sh->sector); 1083 1084 sh->check_state = check_state_check_result; 1085 set_bit(STRIPE_HANDLE, &sh->state); 1086 release_stripe(sh); 1087 } 1088 1089 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu) 1090 { 1091 int disks = sh->disks; 1092 int pd_idx = sh->pd_idx; 1093 int qd_idx = sh->qd_idx; 1094 struct page *xor_dest; 1095 struct page **xor_srcs = percpu->scribble; 1096 struct dma_async_tx_descriptor *tx; 1097 struct async_submit_ctl submit; 1098 int count; 1099 int i; 1100 1101 pr_debug("%s: stripe %llu\n", __func__, 1102 (unsigned long long)sh->sector); 1103 1104 count = 0; 1105 xor_dest = sh->dev[pd_idx].page; 1106 xor_srcs[count++] = xor_dest; 1107 for (i = disks; i--; ) { 1108 if (i == pd_idx || i == qd_idx) 1109 continue; 1110 xor_srcs[count++] = sh->dev[i].page; 1111 } 1112 1113 init_async_submit(&submit, 0, NULL, NULL, NULL, 1114 to_addr_conv(sh, percpu)); 1115 tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, 1116 &sh->ops.zero_sum_result, &submit); 1117 1118 atomic_inc(&sh->count); 1119 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL); 1120 tx = async_trigger_callback(&submit); 1121 } 1122 1123 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp) 1124 { 1125 struct page **srcs = percpu->scribble; 1126 struct async_submit_ctl submit; 1127 int count; 1128 1129 pr_debug("%s: stripe %llu checkp: %d\n", __func__, 1130 (unsigned long long)sh->sector, checkp); 1131 1132 count = set_syndrome_sources(srcs, sh); 1133 if (!checkp) 1134 srcs[count] = NULL; 1135 1136 atomic_inc(&sh->count); 1137 init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check, 1138 sh, to_addr_conv(sh, percpu)); 1139 async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE, 1140 &sh->ops.zero_sum_result, percpu->spare_page, &submit); 1141 } 1142 1143 static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 1144 { 1145 int overlap_clear = 0, i, disks = sh->disks; 1146 struct dma_async_tx_descriptor *tx = NULL; 1147 raid5_conf_t *conf = sh->raid_conf; 1148 int level = conf->level; 1149 struct raid5_percpu *percpu; 1150 unsigned long cpu; 1151 1152 cpu = get_cpu(); 1153 percpu = per_cpu_ptr(conf->percpu, cpu); 1154 if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) { 1155 ops_run_biofill(sh); 1156 overlap_clear++; 1157 } 1158 1159 if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) { 1160 if (level < 6) 1161 tx = ops_run_compute5(sh, percpu); 1162 else { 1163 if (sh->ops.target2 < 0 || sh->ops.target < 0) 1164 tx = ops_run_compute6_1(sh, percpu); 1165 else 1166 tx = ops_run_compute6_2(sh, percpu); 1167 } 1168 /* terminate the chain if reconstruct is not set to be run */ 1169 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) 1170 async_tx_ack(tx); 1171 } 1172 1173 if (test_bit(STRIPE_OP_PREXOR, &ops_request)) 1174 tx = ops_run_prexor(sh, percpu, tx); 1175 1176 if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) { 1177 tx = ops_run_biodrain(sh, tx); 1178 overlap_clear++; 1179 } 1180 1181 if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) { 1182 if (level < 6) 1183 ops_run_reconstruct5(sh, percpu, tx); 1184 else 1185 ops_run_reconstruct6(sh, percpu, tx); 1186 } 1187 1188 if (test_bit(STRIPE_OP_CHECK, &ops_request)) { 1189 if (sh->check_state == check_state_run) 1190 ops_run_check_p(sh, percpu); 1191 else if (sh->check_state == check_state_run_q) 1192 ops_run_check_pq(sh, percpu, 0); 1193 else if (sh->check_state == check_state_run_pq) 1194 ops_run_check_pq(sh, percpu, 1); 1195 else 1196 BUG(); 1197 } 1198 1199 if (overlap_clear) 1200 for (i = disks; i--; ) { 1201 struct r5dev *dev = &sh->dev[i]; 1202 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 1203 wake_up(&sh->raid_conf->wait_for_overlap); 1204 } 1205 put_cpu(); 1206 } 1207 1208 #ifdef CONFIG_MULTICORE_RAID456 1209 static void async_run_ops(void *param, async_cookie_t cookie) 1210 { 1211 struct stripe_head *sh = param; 1212 unsigned long ops_request = sh->ops.request; 1213 1214 clear_bit_unlock(STRIPE_OPS_REQ_PENDING, &sh->state); 1215 wake_up(&sh->ops.wait_for_ops); 1216 1217 __raid_run_ops(sh, ops_request); 1218 release_stripe(sh); 1219 } 1220 1221 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 1222 { 1223 /* since handle_stripe can be called outside of raid5d context 1224 * we need to ensure sh->ops.request is de-staged before another 1225 * request arrives 1226 */ 1227 wait_event(sh->ops.wait_for_ops, 1228 !test_and_set_bit_lock(STRIPE_OPS_REQ_PENDING, &sh->state)); 1229 sh->ops.request = ops_request; 1230 1231 atomic_inc(&sh->count); 1232 async_schedule(async_run_ops, sh); 1233 } 1234 #else 1235 #define raid_run_ops __raid_run_ops 1236 #endif 1237 1238 static int grow_one_stripe(raid5_conf_t *conf) 1239 { 1240 struct stripe_head *sh; 1241 int disks = max(conf->raid_disks, conf->previous_raid_disks); 1242 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); 1243 if (!sh) 1244 return 0; 1245 memset(sh, 0, sizeof(*sh) + (disks-1)*sizeof(struct r5dev)); 1246 sh->raid_conf = conf; 1247 spin_lock_init(&sh->lock); 1248 #ifdef CONFIG_MULTICORE_RAID456 1249 init_waitqueue_head(&sh->ops.wait_for_ops); 1250 #endif 1251 1252 if (grow_buffers(sh, disks)) { 1253 shrink_buffers(sh, disks); 1254 kmem_cache_free(conf->slab_cache, sh); 1255 return 0; 1256 } 1257 /* we just created an active stripe so... */ 1258 atomic_set(&sh->count, 1); 1259 atomic_inc(&conf->active_stripes); 1260 INIT_LIST_HEAD(&sh->lru); 1261 release_stripe(sh); 1262 return 1; 1263 } 1264 1265 static int grow_stripes(raid5_conf_t *conf, int num) 1266 { 1267 struct kmem_cache *sc; 1268 int devs = max(conf->raid_disks, conf->previous_raid_disks); 1269 1270 sprintf(conf->cache_name[0], 1271 "raid%d-%s", conf->level, mdname(conf->mddev)); 1272 sprintf(conf->cache_name[1], 1273 "raid%d-%s-alt", conf->level, mdname(conf->mddev)); 1274 conf->active_name = 0; 1275 sc = kmem_cache_create(conf->cache_name[conf->active_name], 1276 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 1277 0, 0, NULL); 1278 if (!sc) 1279 return 1; 1280 conf->slab_cache = sc; 1281 conf->pool_size = devs; 1282 while (num--) 1283 if (!grow_one_stripe(conf)) 1284 return 1; 1285 return 0; 1286 } 1287 1288 /** 1289 * scribble_len - return the required size of the scribble region 1290 * @num - total number of disks in the array 1291 * 1292 * The size must be enough to contain: 1293 * 1/ a struct page pointer for each device in the array +2 1294 * 2/ room to convert each entry in (1) to its corresponding dma 1295 * (dma_map_page()) or page (page_address()) address. 1296 * 1297 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we 1298 * calculate over all devices (not just the data blocks), using zeros in place 1299 * of the P and Q blocks. 1300 */ 1301 static size_t scribble_len(int num) 1302 { 1303 size_t len; 1304 1305 len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2); 1306 1307 return len; 1308 } 1309 1310 static int resize_stripes(raid5_conf_t *conf, int newsize) 1311 { 1312 /* Make all the stripes able to hold 'newsize' devices. 1313 * New slots in each stripe get 'page' set to a new page. 1314 * 1315 * This happens in stages: 1316 * 1/ create a new kmem_cache and allocate the required number of 1317 * stripe_heads. 1318 * 2/ gather all the old stripe_heads and tranfer the pages across 1319 * to the new stripe_heads. This will have the side effect of 1320 * freezing the array as once all stripe_heads have been collected, 1321 * no IO will be possible. Old stripe heads are freed once their 1322 * pages have been transferred over, and the old kmem_cache is 1323 * freed when all stripes are done. 1324 * 3/ reallocate conf->disks to be suitable bigger. If this fails, 1325 * we simple return a failre status - no need to clean anything up. 1326 * 4/ allocate new pages for the new slots in the new stripe_heads. 1327 * If this fails, we don't bother trying the shrink the 1328 * stripe_heads down again, we just leave them as they are. 1329 * As each stripe_head is processed the new one is released into 1330 * active service. 1331 * 1332 * Once step2 is started, we cannot afford to wait for a write, 1333 * so we use GFP_NOIO allocations. 1334 */ 1335 struct stripe_head *osh, *nsh; 1336 LIST_HEAD(newstripes); 1337 struct disk_info *ndisks; 1338 unsigned long cpu; 1339 int err; 1340 struct kmem_cache *sc; 1341 int i; 1342 1343 if (newsize <= conf->pool_size) 1344 return 0; /* never bother to shrink */ 1345 1346 err = md_allow_write(conf->mddev); 1347 if (err) 1348 return err; 1349 1350 /* Step 1 */ 1351 sc = kmem_cache_create(conf->cache_name[1-conf->active_name], 1352 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev), 1353 0, 0, NULL); 1354 if (!sc) 1355 return -ENOMEM; 1356 1357 for (i = conf->max_nr_stripes; i; i--) { 1358 nsh = kmem_cache_alloc(sc, GFP_KERNEL); 1359 if (!nsh) 1360 break; 1361 1362 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev)); 1363 1364 nsh->raid_conf = conf; 1365 spin_lock_init(&nsh->lock); 1366 #ifdef CONFIG_MULTICORE_RAID456 1367 init_waitqueue_head(&nsh->ops.wait_for_ops); 1368 #endif 1369 1370 list_add(&nsh->lru, &newstripes); 1371 } 1372 if (i) { 1373 /* didn't get enough, give up */ 1374 while (!list_empty(&newstripes)) { 1375 nsh = list_entry(newstripes.next, struct stripe_head, lru); 1376 list_del(&nsh->lru); 1377 kmem_cache_free(sc, nsh); 1378 } 1379 kmem_cache_destroy(sc); 1380 return -ENOMEM; 1381 } 1382 /* Step 2 - Must use GFP_NOIO now. 1383 * OK, we have enough stripes, start collecting inactive 1384 * stripes and copying them over 1385 */ 1386 list_for_each_entry(nsh, &newstripes, lru) { 1387 spin_lock_irq(&conf->device_lock); 1388 wait_event_lock_irq(conf->wait_for_stripe, 1389 !list_empty(&conf->inactive_list), 1390 conf->device_lock, 1391 unplug_slaves(conf->mddev) 1392 ); 1393 osh = get_free_stripe(conf); 1394 spin_unlock_irq(&conf->device_lock); 1395 atomic_set(&nsh->count, 1); 1396 for(i=0; i<conf->pool_size; i++) 1397 nsh->dev[i].page = osh->dev[i].page; 1398 for( ; i<newsize; i++) 1399 nsh->dev[i].page = NULL; 1400 kmem_cache_free(conf->slab_cache, osh); 1401 } 1402 kmem_cache_destroy(conf->slab_cache); 1403 1404 /* Step 3. 1405 * At this point, we are holding all the stripes so the array 1406 * is completely stalled, so now is a good time to resize 1407 * conf->disks and the scribble region 1408 */ 1409 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO); 1410 if (ndisks) { 1411 for (i=0; i<conf->raid_disks; i++) 1412 ndisks[i] = conf->disks[i]; 1413 kfree(conf->disks); 1414 conf->disks = ndisks; 1415 } else 1416 err = -ENOMEM; 1417 1418 get_online_cpus(); 1419 conf->scribble_len = scribble_len(newsize); 1420 for_each_present_cpu(cpu) { 1421 struct raid5_percpu *percpu; 1422 void *scribble; 1423 1424 percpu = per_cpu_ptr(conf->percpu, cpu); 1425 scribble = kmalloc(conf->scribble_len, GFP_NOIO); 1426 1427 if (scribble) { 1428 kfree(percpu->scribble); 1429 percpu->scribble = scribble; 1430 } else { 1431 err = -ENOMEM; 1432 break; 1433 } 1434 } 1435 put_online_cpus(); 1436 1437 /* Step 4, return new stripes to service */ 1438 while(!list_empty(&newstripes)) { 1439 nsh = list_entry(newstripes.next, struct stripe_head, lru); 1440 list_del_init(&nsh->lru); 1441 1442 for (i=conf->raid_disks; i < newsize; i++) 1443 if (nsh->dev[i].page == NULL) { 1444 struct page *p = alloc_page(GFP_NOIO); 1445 nsh->dev[i].page = p; 1446 if (!p) 1447 err = -ENOMEM; 1448 } 1449 release_stripe(nsh); 1450 } 1451 /* critical section pass, GFP_NOIO no longer needed */ 1452 1453 conf->slab_cache = sc; 1454 conf->active_name = 1-conf->active_name; 1455 conf->pool_size = newsize; 1456 return err; 1457 } 1458 1459 static int drop_one_stripe(raid5_conf_t *conf) 1460 { 1461 struct stripe_head *sh; 1462 1463 spin_lock_irq(&conf->device_lock); 1464 sh = get_free_stripe(conf); 1465 spin_unlock_irq(&conf->device_lock); 1466 if (!sh) 1467 return 0; 1468 BUG_ON(atomic_read(&sh->count)); 1469 shrink_buffers(sh, conf->pool_size); 1470 kmem_cache_free(conf->slab_cache, sh); 1471 atomic_dec(&conf->active_stripes); 1472 return 1; 1473 } 1474 1475 static void shrink_stripes(raid5_conf_t *conf) 1476 { 1477 while (drop_one_stripe(conf)) 1478 ; 1479 1480 if (conf->slab_cache) 1481 kmem_cache_destroy(conf->slab_cache); 1482 conf->slab_cache = NULL; 1483 } 1484 1485 static void raid5_end_read_request(struct bio * bi, int error) 1486 { 1487 struct stripe_head *sh = bi->bi_private; 1488 raid5_conf_t *conf = sh->raid_conf; 1489 int disks = sh->disks, i; 1490 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 1491 char b[BDEVNAME_SIZE]; 1492 mdk_rdev_t *rdev; 1493 1494 1495 for (i=0 ; i<disks; i++) 1496 if (bi == &sh->dev[i].req) 1497 break; 1498 1499 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n", 1500 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 1501 uptodate); 1502 if (i == disks) { 1503 BUG(); 1504 return; 1505 } 1506 1507 if (uptodate) { 1508 set_bit(R5_UPTODATE, &sh->dev[i].flags); 1509 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1510 rdev = conf->disks[i].rdev; 1511 printk_rl(KERN_INFO "raid5:%s: read error corrected" 1512 " (%lu sectors at %llu on %s)\n", 1513 mdname(conf->mddev), STRIPE_SECTORS, 1514 (unsigned long long)(sh->sector 1515 + rdev->data_offset), 1516 bdevname(rdev->bdev, b)); 1517 clear_bit(R5_ReadError, &sh->dev[i].flags); 1518 clear_bit(R5_ReWrite, &sh->dev[i].flags); 1519 } 1520 if (atomic_read(&conf->disks[i].rdev->read_errors)) 1521 atomic_set(&conf->disks[i].rdev->read_errors, 0); 1522 } else { 1523 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b); 1524 int retry = 0; 1525 rdev = conf->disks[i].rdev; 1526 1527 clear_bit(R5_UPTODATE, &sh->dev[i].flags); 1528 atomic_inc(&rdev->read_errors); 1529 if (conf->mddev->degraded) 1530 printk_rl(KERN_WARNING 1531 "raid5:%s: read error not correctable " 1532 "(sector %llu on %s).\n", 1533 mdname(conf->mddev), 1534 (unsigned long long)(sh->sector 1535 + rdev->data_offset), 1536 bdn); 1537 else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) 1538 /* Oh, no!!! */ 1539 printk_rl(KERN_WARNING 1540 "raid5:%s: read error NOT corrected!! " 1541 "(sector %llu on %s).\n", 1542 mdname(conf->mddev), 1543 (unsigned long long)(sh->sector 1544 + rdev->data_offset), 1545 bdn); 1546 else if (atomic_read(&rdev->read_errors) 1547 > conf->max_nr_stripes) 1548 printk(KERN_WARNING 1549 "raid5:%s: Too many read errors, failing device %s.\n", 1550 mdname(conf->mddev), bdn); 1551 else 1552 retry = 1; 1553 if (retry) 1554 set_bit(R5_ReadError, &sh->dev[i].flags); 1555 else { 1556 clear_bit(R5_ReadError, &sh->dev[i].flags); 1557 clear_bit(R5_ReWrite, &sh->dev[i].flags); 1558 md_error(conf->mddev, rdev); 1559 } 1560 } 1561 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 1562 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1563 set_bit(STRIPE_HANDLE, &sh->state); 1564 release_stripe(sh); 1565 } 1566 1567 static void raid5_end_write_request(struct bio *bi, int error) 1568 { 1569 struct stripe_head *sh = bi->bi_private; 1570 raid5_conf_t *conf = sh->raid_conf; 1571 int disks = sh->disks, i; 1572 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 1573 1574 for (i=0 ; i<disks; i++) 1575 if (bi == &sh->dev[i].req) 1576 break; 1577 1578 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n", 1579 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 1580 uptodate); 1581 if (i == disks) { 1582 BUG(); 1583 return; 1584 } 1585 1586 if (!uptodate) 1587 md_error(conf->mddev, conf->disks[i].rdev); 1588 1589 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 1590 1591 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1592 set_bit(STRIPE_HANDLE, &sh->state); 1593 release_stripe(sh); 1594 } 1595 1596 1597 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous); 1598 1599 static void raid5_build_block(struct stripe_head *sh, int i, int previous) 1600 { 1601 struct r5dev *dev = &sh->dev[i]; 1602 1603 bio_init(&dev->req); 1604 dev->req.bi_io_vec = &dev->vec; 1605 dev->req.bi_vcnt++; 1606 dev->req.bi_max_vecs++; 1607 dev->vec.bv_page = dev->page; 1608 dev->vec.bv_len = STRIPE_SIZE; 1609 dev->vec.bv_offset = 0; 1610 1611 dev->req.bi_sector = sh->sector; 1612 dev->req.bi_private = sh; 1613 1614 dev->flags = 0; 1615 dev->sector = compute_blocknr(sh, i, previous); 1616 } 1617 1618 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 1619 { 1620 char b[BDEVNAME_SIZE]; 1621 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 1622 pr_debug("raid5: error called\n"); 1623 1624 if (!test_bit(Faulty, &rdev->flags)) { 1625 set_bit(MD_CHANGE_DEVS, &mddev->flags); 1626 if (test_and_clear_bit(In_sync, &rdev->flags)) { 1627 unsigned long flags; 1628 spin_lock_irqsave(&conf->device_lock, flags); 1629 mddev->degraded++; 1630 spin_unlock_irqrestore(&conf->device_lock, flags); 1631 /* 1632 * if recovery was running, make sure it aborts. 1633 */ 1634 set_bit(MD_RECOVERY_INTR, &mddev->recovery); 1635 } 1636 set_bit(Faulty, &rdev->flags); 1637 printk(KERN_ALERT 1638 "raid5: Disk failure on %s, disabling device.\n" 1639 "raid5: Operation continuing on %d devices.\n", 1640 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); 1641 } 1642 } 1643 1644 /* 1645 * Input: a 'big' sector number, 1646 * Output: index of the data and parity disk, and the sector # in them. 1647 */ 1648 static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, 1649 int previous, int *dd_idx, 1650 struct stripe_head *sh) 1651 { 1652 long stripe; 1653 unsigned long chunk_number; 1654 unsigned int chunk_offset; 1655 int pd_idx, qd_idx; 1656 int ddf_layout = 0; 1657 sector_t new_sector; 1658 int algorithm = previous ? conf->prev_algo 1659 : conf->algorithm; 1660 int sectors_per_chunk = previous ? conf->prev_chunk_sectors 1661 : conf->chunk_sectors; 1662 int raid_disks = previous ? conf->previous_raid_disks 1663 : conf->raid_disks; 1664 int data_disks = raid_disks - conf->max_degraded; 1665 1666 /* First compute the information on this sector */ 1667 1668 /* 1669 * Compute the chunk number and the sector offset inside the chunk 1670 */ 1671 chunk_offset = sector_div(r_sector, sectors_per_chunk); 1672 chunk_number = r_sector; 1673 BUG_ON(r_sector != chunk_number); 1674 1675 /* 1676 * Compute the stripe number 1677 */ 1678 stripe = chunk_number / data_disks; 1679 1680 /* 1681 * Compute the data disk and parity disk indexes inside the stripe 1682 */ 1683 *dd_idx = chunk_number % data_disks; 1684 1685 /* 1686 * Select the parity disk based on the user selected algorithm. 1687 */ 1688 pd_idx = qd_idx = ~0; 1689 switch(conf->level) { 1690 case 4: 1691 pd_idx = data_disks; 1692 break; 1693 case 5: 1694 switch (algorithm) { 1695 case ALGORITHM_LEFT_ASYMMETRIC: 1696 pd_idx = data_disks - stripe % raid_disks; 1697 if (*dd_idx >= pd_idx) 1698 (*dd_idx)++; 1699 break; 1700 case ALGORITHM_RIGHT_ASYMMETRIC: 1701 pd_idx = stripe % raid_disks; 1702 if (*dd_idx >= pd_idx) 1703 (*dd_idx)++; 1704 break; 1705 case ALGORITHM_LEFT_SYMMETRIC: 1706 pd_idx = data_disks - stripe % raid_disks; 1707 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; 1708 break; 1709 case ALGORITHM_RIGHT_SYMMETRIC: 1710 pd_idx = stripe % raid_disks; 1711 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; 1712 break; 1713 case ALGORITHM_PARITY_0: 1714 pd_idx = 0; 1715 (*dd_idx)++; 1716 break; 1717 case ALGORITHM_PARITY_N: 1718 pd_idx = data_disks; 1719 break; 1720 default: 1721 printk(KERN_ERR "raid5: unsupported algorithm %d\n", 1722 algorithm); 1723 BUG(); 1724 } 1725 break; 1726 case 6: 1727 1728 switch (algorithm) { 1729 case ALGORITHM_LEFT_ASYMMETRIC: 1730 pd_idx = raid_disks - 1 - (stripe % raid_disks); 1731 qd_idx = pd_idx + 1; 1732 if (pd_idx == raid_disks-1) { 1733 (*dd_idx)++; /* Q D D D P */ 1734 qd_idx = 0; 1735 } else if (*dd_idx >= pd_idx) 1736 (*dd_idx) += 2; /* D D P Q D */ 1737 break; 1738 case ALGORITHM_RIGHT_ASYMMETRIC: 1739 pd_idx = stripe % raid_disks; 1740 qd_idx = pd_idx + 1; 1741 if (pd_idx == raid_disks-1) { 1742 (*dd_idx)++; /* Q D D D P */ 1743 qd_idx = 0; 1744 } else if (*dd_idx >= pd_idx) 1745 (*dd_idx) += 2; /* D D P Q D */ 1746 break; 1747 case ALGORITHM_LEFT_SYMMETRIC: 1748 pd_idx = raid_disks - 1 - (stripe % raid_disks); 1749 qd_idx = (pd_idx + 1) % raid_disks; 1750 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks; 1751 break; 1752 case ALGORITHM_RIGHT_SYMMETRIC: 1753 pd_idx = stripe % raid_disks; 1754 qd_idx = (pd_idx + 1) % raid_disks; 1755 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks; 1756 break; 1757 1758 case ALGORITHM_PARITY_0: 1759 pd_idx = 0; 1760 qd_idx = 1; 1761 (*dd_idx) += 2; 1762 break; 1763 case ALGORITHM_PARITY_N: 1764 pd_idx = data_disks; 1765 qd_idx = data_disks + 1; 1766 break; 1767 1768 case ALGORITHM_ROTATING_ZERO_RESTART: 1769 /* Exactly the same as RIGHT_ASYMMETRIC, but or 1770 * of blocks for computing Q is different. 1771 */ 1772 pd_idx = stripe % raid_disks; 1773 qd_idx = pd_idx + 1; 1774 if (pd_idx == raid_disks-1) { 1775 (*dd_idx)++; /* Q D D D P */ 1776 qd_idx = 0; 1777 } else if (*dd_idx >= pd_idx) 1778 (*dd_idx) += 2; /* D D P Q D */ 1779 ddf_layout = 1; 1780 break; 1781 1782 case ALGORITHM_ROTATING_N_RESTART: 1783 /* Same a left_asymmetric, by first stripe is 1784 * D D D P Q rather than 1785 * Q D D D P 1786 */ 1787 pd_idx = raid_disks - 1 - ((stripe + 1) % raid_disks); 1788 qd_idx = pd_idx + 1; 1789 if (pd_idx == raid_disks-1) { 1790 (*dd_idx)++; /* Q D D D P */ 1791 qd_idx = 0; 1792 } else if (*dd_idx >= pd_idx) 1793 (*dd_idx) += 2; /* D D P Q D */ 1794 ddf_layout = 1; 1795 break; 1796 1797 case ALGORITHM_ROTATING_N_CONTINUE: 1798 /* Same as left_symmetric but Q is before P */ 1799 pd_idx = raid_disks - 1 - (stripe % raid_disks); 1800 qd_idx = (pd_idx + raid_disks - 1) % raid_disks; 1801 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; 1802 ddf_layout = 1; 1803 break; 1804 1805 case ALGORITHM_LEFT_ASYMMETRIC_6: 1806 /* RAID5 left_asymmetric, with Q on last device */ 1807 pd_idx = data_disks - stripe % (raid_disks-1); 1808 if (*dd_idx >= pd_idx) 1809 (*dd_idx)++; 1810 qd_idx = raid_disks - 1; 1811 break; 1812 1813 case ALGORITHM_RIGHT_ASYMMETRIC_6: 1814 pd_idx = stripe % (raid_disks-1); 1815 if (*dd_idx >= pd_idx) 1816 (*dd_idx)++; 1817 qd_idx = raid_disks - 1; 1818 break; 1819 1820 case ALGORITHM_LEFT_SYMMETRIC_6: 1821 pd_idx = data_disks - stripe % (raid_disks-1); 1822 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1); 1823 qd_idx = raid_disks - 1; 1824 break; 1825 1826 case ALGORITHM_RIGHT_SYMMETRIC_6: 1827 pd_idx = stripe % (raid_disks-1); 1828 *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1); 1829 qd_idx = raid_disks - 1; 1830 break; 1831 1832 case ALGORITHM_PARITY_0_6: 1833 pd_idx = 0; 1834 (*dd_idx)++; 1835 qd_idx = raid_disks - 1; 1836 break; 1837 1838 1839 default: 1840 printk(KERN_CRIT "raid6: unsupported algorithm %d\n", 1841 algorithm); 1842 BUG(); 1843 } 1844 break; 1845 } 1846 1847 if (sh) { 1848 sh->pd_idx = pd_idx; 1849 sh->qd_idx = qd_idx; 1850 sh->ddf_layout = ddf_layout; 1851 } 1852 /* 1853 * Finally, compute the new sector number 1854 */ 1855 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; 1856 return new_sector; 1857 } 1858 1859 1860 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous) 1861 { 1862 raid5_conf_t *conf = sh->raid_conf; 1863 int raid_disks = sh->disks; 1864 int data_disks = raid_disks - conf->max_degraded; 1865 sector_t new_sector = sh->sector, check; 1866 int sectors_per_chunk = previous ? conf->prev_chunk_sectors 1867 : conf->chunk_sectors; 1868 int algorithm = previous ? conf->prev_algo 1869 : conf->algorithm; 1870 sector_t stripe; 1871 int chunk_offset; 1872 int chunk_number, dummy1, dd_idx = i; 1873 sector_t r_sector; 1874 struct stripe_head sh2; 1875 1876 1877 chunk_offset = sector_div(new_sector, sectors_per_chunk); 1878 stripe = new_sector; 1879 BUG_ON(new_sector != stripe); 1880 1881 if (i == sh->pd_idx) 1882 return 0; 1883 switch(conf->level) { 1884 case 4: break; 1885 case 5: 1886 switch (algorithm) { 1887 case ALGORITHM_LEFT_ASYMMETRIC: 1888 case ALGORITHM_RIGHT_ASYMMETRIC: 1889 if (i > sh->pd_idx) 1890 i--; 1891 break; 1892 case ALGORITHM_LEFT_SYMMETRIC: 1893 case ALGORITHM_RIGHT_SYMMETRIC: 1894 if (i < sh->pd_idx) 1895 i += raid_disks; 1896 i -= (sh->pd_idx + 1); 1897 break; 1898 case ALGORITHM_PARITY_0: 1899 i -= 1; 1900 break; 1901 case ALGORITHM_PARITY_N: 1902 break; 1903 default: 1904 printk(KERN_ERR "raid5: unsupported algorithm %d\n", 1905 algorithm); 1906 BUG(); 1907 } 1908 break; 1909 case 6: 1910 if (i == sh->qd_idx) 1911 return 0; /* It is the Q disk */ 1912 switch (algorithm) { 1913 case ALGORITHM_LEFT_ASYMMETRIC: 1914 case ALGORITHM_RIGHT_ASYMMETRIC: 1915 case ALGORITHM_ROTATING_ZERO_RESTART: 1916 case ALGORITHM_ROTATING_N_RESTART: 1917 if (sh->pd_idx == raid_disks-1) 1918 i--; /* Q D D D P */ 1919 else if (i > sh->pd_idx) 1920 i -= 2; /* D D P Q D */ 1921 break; 1922 case ALGORITHM_LEFT_SYMMETRIC: 1923 case ALGORITHM_RIGHT_SYMMETRIC: 1924 if (sh->pd_idx == raid_disks-1) 1925 i--; /* Q D D D P */ 1926 else { 1927 /* D D P Q D */ 1928 if (i < sh->pd_idx) 1929 i += raid_disks; 1930 i -= (sh->pd_idx + 2); 1931 } 1932 break; 1933 case ALGORITHM_PARITY_0: 1934 i -= 2; 1935 break; 1936 case ALGORITHM_PARITY_N: 1937 break; 1938 case ALGORITHM_ROTATING_N_CONTINUE: 1939 /* Like left_symmetric, but P is before Q */ 1940 if (sh->pd_idx == 0) 1941 i--; /* P D D D Q */ 1942 else { 1943 /* D D Q P D */ 1944 if (i < sh->pd_idx) 1945 i += raid_disks; 1946 i -= (sh->pd_idx + 1); 1947 } 1948 break; 1949 case ALGORITHM_LEFT_ASYMMETRIC_6: 1950 case ALGORITHM_RIGHT_ASYMMETRIC_6: 1951 if (i > sh->pd_idx) 1952 i--; 1953 break; 1954 case ALGORITHM_LEFT_SYMMETRIC_6: 1955 case ALGORITHM_RIGHT_SYMMETRIC_6: 1956 if (i < sh->pd_idx) 1957 i += data_disks + 1; 1958 i -= (sh->pd_idx + 1); 1959 break; 1960 case ALGORITHM_PARITY_0_6: 1961 i -= 1; 1962 break; 1963 default: 1964 printk(KERN_CRIT "raid6: unsupported algorithm %d\n", 1965 algorithm); 1966 BUG(); 1967 } 1968 break; 1969 } 1970 1971 chunk_number = stripe * data_disks + i; 1972 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; 1973 1974 check = raid5_compute_sector(conf, r_sector, 1975 previous, &dummy1, &sh2); 1976 if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx 1977 || sh2.qd_idx != sh->qd_idx) { 1978 printk(KERN_ERR "compute_blocknr: map not correct\n"); 1979 return 0; 1980 } 1981 return r_sector; 1982 } 1983 1984 1985 static void 1986 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s, 1987 int rcw, int expand) 1988 { 1989 int i, pd_idx = sh->pd_idx, disks = sh->disks; 1990 raid5_conf_t *conf = sh->raid_conf; 1991 int level = conf->level; 1992 1993 if (rcw) { 1994 /* if we are not expanding this is a proper write request, and 1995 * there will be bios with new data to be drained into the 1996 * stripe cache 1997 */ 1998 if (!expand) { 1999 sh->reconstruct_state = reconstruct_state_drain_run; 2000 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); 2001 } else 2002 sh->reconstruct_state = reconstruct_state_run; 2003 2004 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request); 2005 2006 for (i = disks; i--; ) { 2007 struct r5dev *dev = &sh->dev[i]; 2008 2009 if (dev->towrite) { 2010 set_bit(R5_LOCKED, &dev->flags); 2011 set_bit(R5_Wantdrain, &dev->flags); 2012 if (!expand) 2013 clear_bit(R5_UPTODATE, &dev->flags); 2014 s->locked++; 2015 } 2016 } 2017 if (s->locked + conf->max_degraded == disks) 2018 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state)) 2019 atomic_inc(&conf->pending_full_writes); 2020 } else { 2021 BUG_ON(level == 6); 2022 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) || 2023 test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags))); 2024 2025 sh->reconstruct_state = reconstruct_state_prexor_drain_run; 2026 set_bit(STRIPE_OP_PREXOR, &s->ops_request); 2027 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); 2028 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request); 2029 2030 for (i = disks; i--; ) { 2031 struct r5dev *dev = &sh->dev[i]; 2032 if (i == pd_idx) 2033 continue; 2034 2035 if (dev->towrite && 2036 (test_bit(R5_UPTODATE, &dev->flags) || 2037 test_bit(R5_Wantcompute, &dev->flags))) { 2038 set_bit(R5_Wantdrain, &dev->flags); 2039 set_bit(R5_LOCKED, &dev->flags); 2040 clear_bit(R5_UPTODATE, &dev->flags); 2041 s->locked++; 2042 } 2043 } 2044 } 2045 2046 /* keep the parity disk(s) locked while asynchronous operations 2047 * are in flight 2048 */ 2049 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 2050 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 2051 s->locked++; 2052 2053 if (level == 6) { 2054 int qd_idx = sh->qd_idx; 2055 struct r5dev *dev = &sh->dev[qd_idx]; 2056 2057 set_bit(R5_LOCKED, &dev->flags); 2058 clear_bit(R5_UPTODATE, &dev->flags); 2059 s->locked++; 2060 } 2061 2062 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n", 2063 __func__, (unsigned long long)sh->sector, 2064 s->locked, s->ops_request); 2065 } 2066 2067 /* 2068 * Each stripe/dev can have one or more bion attached. 2069 * toread/towrite point to the first in a chain. 2070 * The bi_next chain must be in order. 2071 */ 2072 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) 2073 { 2074 struct bio **bip; 2075 raid5_conf_t *conf = sh->raid_conf; 2076 int firstwrite=0; 2077 2078 pr_debug("adding bh b#%llu to stripe s#%llu\n", 2079 (unsigned long long)bi->bi_sector, 2080 (unsigned long long)sh->sector); 2081 2082 2083 spin_lock(&sh->lock); 2084 spin_lock_irq(&conf->device_lock); 2085 if (forwrite) { 2086 bip = &sh->dev[dd_idx].towrite; 2087 if (*bip == NULL && sh->dev[dd_idx].written == NULL) 2088 firstwrite = 1; 2089 } else 2090 bip = &sh->dev[dd_idx].toread; 2091 while (*bip && (*bip)->bi_sector < bi->bi_sector) { 2092 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) 2093 goto overlap; 2094 bip = & (*bip)->bi_next; 2095 } 2096 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) 2097 goto overlap; 2098 2099 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next); 2100 if (*bip) 2101 bi->bi_next = *bip; 2102 *bip = bi; 2103 bi->bi_phys_segments++; 2104 spin_unlock_irq(&conf->device_lock); 2105 spin_unlock(&sh->lock); 2106 2107 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n", 2108 (unsigned long long)bi->bi_sector, 2109 (unsigned long long)sh->sector, dd_idx); 2110 2111 if (conf->mddev->bitmap && firstwrite) { 2112 bitmap_startwrite(conf->mddev->bitmap, sh->sector, 2113 STRIPE_SECTORS, 0); 2114 sh->bm_seq = conf->seq_flush+1; 2115 set_bit(STRIPE_BIT_DELAY, &sh->state); 2116 } 2117 2118 if (forwrite) { 2119 /* check if page is covered */ 2120 sector_t sector = sh->dev[dd_idx].sector; 2121 for (bi=sh->dev[dd_idx].towrite; 2122 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && 2123 bi && bi->bi_sector <= sector; 2124 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { 2125 if (bi->bi_sector + (bi->bi_size>>9) >= sector) 2126 sector = bi->bi_sector + (bi->bi_size>>9); 2127 } 2128 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) 2129 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); 2130 } 2131 return 1; 2132 2133 overlap: 2134 set_bit(R5_Overlap, &sh->dev[dd_idx].flags); 2135 spin_unlock_irq(&conf->device_lock); 2136 spin_unlock(&sh->lock); 2137 return 0; 2138 } 2139 2140 static void end_reshape(raid5_conf_t *conf); 2141 2142 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous, 2143 struct stripe_head *sh) 2144 { 2145 int sectors_per_chunk = 2146 previous ? conf->prev_chunk_sectors : conf->chunk_sectors; 2147 int dd_idx; 2148 int chunk_offset = sector_div(stripe, sectors_per_chunk); 2149 int disks = previous ? conf->previous_raid_disks : conf->raid_disks; 2150 2151 raid5_compute_sector(conf, 2152 stripe * (disks - conf->max_degraded) 2153 *sectors_per_chunk + chunk_offset, 2154 previous, 2155 &dd_idx, sh); 2156 } 2157 2158 static void 2159 handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, 2160 struct stripe_head_state *s, int disks, 2161 struct bio **return_bi) 2162 { 2163 int i; 2164 for (i = disks; i--; ) { 2165 struct bio *bi; 2166 int bitmap_end = 0; 2167 2168 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 2169 mdk_rdev_t *rdev; 2170 rcu_read_lock(); 2171 rdev = rcu_dereference(conf->disks[i].rdev); 2172 if (rdev && test_bit(In_sync, &rdev->flags)) 2173 /* multiple read failures in one stripe */ 2174 md_error(conf->mddev, rdev); 2175 rcu_read_unlock(); 2176 } 2177 spin_lock_irq(&conf->device_lock); 2178 /* fail all writes first */ 2179 bi = sh->dev[i].towrite; 2180 sh->dev[i].towrite = NULL; 2181 if (bi) { 2182 s->to_write--; 2183 bitmap_end = 1; 2184 } 2185 2186 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 2187 wake_up(&conf->wait_for_overlap); 2188 2189 while (bi && bi->bi_sector < 2190 sh->dev[i].sector + STRIPE_SECTORS) { 2191 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 2192 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2193 if (!raid5_dec_bi_phys_segments(bi)) { 2194 md_write_end(conf->mddev); 2195 bi->bi_next = *return_bi; 2196 *return_bi = bi; 2197 } 2198 bi = nextbi; 2199 } 2200 /* and fail all 'written' */ 2201 bi = sh->dev[i].written; 2202 sh->dev[i].written = NULL; 2203 if (bi) bitmap_end = 1; 2204 while (bi && bi->bi_sector < 2205 sh->dev[i].sector + STRIPE_SECTORS) { 2206 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 2207 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2208 if (!raid5_dec_bi_phys_segments(bi)) { 2209 md_write_end(conf->mddev); 2210 bi->bi_next = *return_bi; 2211 *return_bi = bi; 2212 } 2213 bi = bi2; 2214 } 2215 2216 /* fail any reads if this device is non-operational and 2217 * the data has not reached the cache yet. 2218 */ 2219 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) && 2220 (!test_bit(R5_Insync, &sh->dev[i].flags) || 2221 test_bit(R5_ReadError, &sh->dev[i].flags))) { 2222 bi = sh->dev[i].toread; 2223 sh->dev[i].toread = NULL; 2224 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 2225 wake_up(&conf->wait_for_overlap); 2226 if (bi) s->to_read--; 2227 while (bi && bi->bi_sector < 2228 sh->dev[i].sector + STRIPE_SECTORS) { 2229 struct bio *nextbi = 2230 r5_next_bio(bi, sh->dev[i].sector); 2231 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2232 if (!raid5_dec_bi_phys_segments(bi)) { 2233 bi->bi_next = *return_bi; 2234 *return_bi = bi; 2235 } 2236 bi = nextbi; 2237 } 2238 } 2239 spin_unlock_irq(&conf->device_lock); 2240 if (bitmap_end) 2241 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 2242 STRIPE_SECTORS, 0, 0); 2243 } 2244 2245 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) 2246 if (atomic_dec_and_test(&conf->pending_full_writes)) 2247 md_wakeup_thread(conf->mddev->thread); 2248 } 2249 2250 /* fetch_block5 - checks the given member device to see if its data needs 2251 * to be read or computed to satisfy a request. 2252 * 2253 * Returns 1 when no more member devices need to be checked, otherwise returns 2254 * 0 to tell the loop in handle_stripe_fill5 to continue 2255 */ 2256 static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s, 2257 int disk_idx, int disks) 2258 { 2259 struct r5dev *dev = &sh->dev[disk_idx]; 2260 struct r5dev *failed_dev = &sh->dev[s->failed_num]; 2261 2262 /* is the data in this block needed, and can we get it? */ 2263 if (!test_bit(R5_LOCKED, &dev->flags) && 2264 !test_bit(R5_UPTODATE, &dev->flags) && 2265 (dev->toread || 2266 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 2267 s->syncing || s->expanding || 2268 (s->failed && 2269 (failed_dev->toread || 2270 (failed_dev->towrite && 2271 !test_bit(R5_OVERWRITE, &failed_dev->flags)))))) { 2272 /* We would like to get this block, possibly by computing it, 2273 * otherwise read it if the backing disk is insync 2274 */ 2275 if ((s->uptodate == disks - 1) && 2276 (s->failed && disk_idx == s->failed_num)) { 2277 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2278 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2279 set_bit(R5_Wantcompute, &dev->flags); 2280 sh->ops.target = disk_idx; 2281 sh->ops.target2 = -1; 2282 s->req_compute = 1; 2283 /* Careful: from this point on 'uptodate' is in the eye 2284 * of raid_run_ops which services 'compute' operations 2285 * before writes. R5_Wantcompute flags a block that will 2286 * be R5_UPTODATE by the time it is needed for a 2287 * subsequent operation. 2288 */ 2289 s->uptodate++; 2290 return 1; /* uptodate + compute == disks */ 2291 } else if (test_bit(R5_Insync, &dev->flags)) { 2292 set_bit(R5_LOCKED, &dev->flags); 2293 set_bit(R5_Wantread, &dev->flags); 2294 s->locked++; 2295 pr_debug("Reading block %d (sync=%d)\n", disk_idx, 2296 s->syncing); 2297 } 2298 } 2299 2300 return 0; 2301 } 2302 2303 /** 2304 * handle_stripe_fill5 - read or compute data to satisfy pending requests. 2305 */ 2306 static void handle_stripe_fill5(struct stripe_head *sh, 2307 struct stripe_head_state *s, int disks) 2308 { 2309 int i; 2310 2311 /* look for blocks to read/compute, skip this if a compute 2312 * is already in flight, or if the stripe contents are in the 2313 * midst of changing due to a write 2314 */ 2315 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state && 2316 !sh->reconstruct_state) 2317 for (i = disks; i--; ) 2318 if (fetch_block5(sh, s, i, disks)) 2319 break; 2320 set_bit(STRIPE_HANDLE, &sh->state); 2321 } 2322 2323 /* fetch_block6 - checks the given member device to see if its data needs 2324 * to be read or computed to satisfy a request. 2325 * 2326 * Returns 1 when no more member devices need to be checked, otherwise returns 2327 * 0 to tell the loop in handle_stripe_fill6 to continue 2328 */ 2329 static int fetch_block6(struct stripe_head *sh, struct stripe_head_state *s, 2330 struct r6_state *r6s, int disk_idx, int disks) 2331 { 2332 struct r5dev *dev = &sh->dev[disk_idx]; 2333 struct r5dev *fdev[2] = { &sh->dev[r6s->failed_num[0]], 2334 &sh->dev[r6s->failed_num[1]] }; 2335 2336 if (!test_bit(R5_LOCKED, &dev->flags) && 2337 !test_bit(R5_UPTODATE, &dev->flags) && 2338 (dev->toread || 2339 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 2340 s->syncing || s->expanding || 2341 (s->failed >= 1 && 2342 (fdev[0]->toread || s->to_write)) || 2343 (s->failed >= 2 && 2344 (fdev[1]->toread || s->to_write)))) { 2345 /* we would like to get this block, possibly by computing it, 2346 * otherwise read it if the backing disk is insync 2347 */ 2348 BUG_ON(test_bit(R5_Wantcompute, &dev->flags)); 2349 BUG_ON(test_bit(R5_Wantread, &dev->flags)); 2350 if ((s->uptodate == disks - 1) && 2351 (s->failed && (disk_idx == r6s->failed_num[0] || 2352 disk_idx == r6s->failed_num[1]))) { 2353 /* have disk failed, and we're requested to fetch it; 2354 * do compute it 2355 */ 2356 pr_debug("Computing stripe %llu block %d\n", 2357 (unsigned long long)sh->sector, disk_idx); 2358 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2359 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2360 set_bit(R5_Wantcompute, &dev->flags); 2361 sh->ops.target = disk_idx; 2362 sh->ops.target2 = -1; /* no 2nd target */ 2363 s->req_compute = 1; 2364 s->uptodate++; 2365 return 1; 2366 } else if (s->uptodate == disks-2 && s->failed >= 2) { 2367 /* Computing 2-failure is *very* expensive; only 2368 * do it if failed >= 2 2369 */ 2370 int other; 2371 for (other = disks; other--; ) { 2372 if (other == disk_idx) 2373 continue; 2374 if (!test_bit(R5_UPTODATE, 2375 &sh->dev[other].flags)) 2376 break; 2377 } 2378 BUG_ON(other < 0); 2379 pr_debug("Computing stripe %llu blocks %d,%d\n", 2380 (unsigned long long)sh->sector, 2381 disk_idx, other); 2382 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2383 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2384 set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags); 2385 set_bit(R5_Wantcompute, &sh->dev[other].flags); 2386 sh->ops.target = disk_idx; 2387 sh->ops.target2 = other; 2388 s->uptodate += 2; 2389 s->req_compute = 1; 2390 return 1; 2391 } else if (test_bit(R5_Insync, &dev->flags)) { 2392 set_bit(R5_LOCKED, &dev->flags); 2393 set_bit(R5_Wantread, &dev->flags); 2394 s->locked++; 2395 pr_debug("Reading block %d (sync=%d)\n", 2396 disk_idx, s->syncing); 2397 } 2398 } 2399 2400 return 0; 2401 } 2402 2403 /** 2404 * handle_stripe_fill6 - read or compute data to satisfy pending requests. 2405 */ 2406 static void handle_stripe_fill6(struct stripe_head *sh, 2407 struct stripe_head_state *s, struct r6_state *r6s, 2408 int disks) 2409 { 2410 int i; 2411 2412 /* look for blocks to read/compute, skip this if a compute 2413 * is already in flight, or if the stripe contents are in the 2414 * midst of changing due to a write 2415 */ 2416 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state && 2417 !sh->reconstruct_state) 2418 for (i = disks; i--; ) 2419 if (fetch_block6(sh, s, r6s, i, disks)) 2420 break; 2421 set_bit(STRIPE_HANDLE, &sh->state); 2422 } 2423 2424 2425 /* handle_stripe_clean_event 2426 * any written block on an uptodate or failed drive can be returned. 2427 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but 2428 * never LOCKED, so we don't need to test 'failed' directly. 2429 */ 2430 static void handle_stripe_clean_event(raid5_conf_t *conf, 2431 struct stripe_head *sh, int disks, struct bio **return_bi) 2432 { 2433 int i; 2434 struct r5dev *dev; 2435 2436 for (i = disks; i--; ) 2437 if (sh->dev[i].written) { 2438 dev = &sh->dev[i]; 2439 if (!test_bit(R5_LOCKED, &dev->flags) && 2440 test_bit(R5_UPTODATE, &dev->flags)) { 2441 /* We can return any write requests */ 2442 struct bio *wbi, *wbi2; 2443 int bitmap_end = 0; 2444 pr_debug("Return write for disc %d\n", i); 2445 spin_lock_irq(&conf->device_lock); 2446 wbi = dev->written; 2447 dev->written = NULL; 2448 while (wbi && wbi->bi_sector < 2449 dev->sector + STRIPE_SECTORS) { 2450 wbi2 = r5_next_bio(wbi, dev->sector); 2451 if (!raid5_dec_bi_phys_segments(wbi)) { 2452 md_write_end(conf->mddev); 2453 wbi->bi_next = *return_bi; 2454 *return_bi = wbi; 2455 } 2456 wbi = wbi2; 2457 } 2458 if (dev->towrite == NULL) 2459 bitmap_end = 1; 2460 spin_unlock_irq(&conf->device_lock); 2461 if (bitmap_end) 2462 bitmap_endwrite(conf->mddev->bitmap, 2463 sh->sector, 2464 STRIPE_SECTORS, 2465 !test_bit(STRIPE_DEGRADED, &sh->state), 2466 0); 2467 } 2468 } 2469 2470 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) 2471 if (atomic_dec_and_test(&conf->pending_full_writes)) 2472 md_wakeup_thread(conf->mddev->thread); 2473 } 2474 2475 static void handle_stripe_dirtying5(raid5_conf_t *conf, 2476 struct stripe_head *sh, struct stripe_head_state *s, int disks) 2477 { 2478 int rmw = 0, rcw = 0, i; 2479 for (i = disks; i--; ) { 2480 /* would I have to read this buffer for read_modify_write */ 2481 struct r5dev *dev = &sh->dev[i]; 2482 if ((dev->towrite || i == sh->pd_idx) && 2483 !test_bit(R5_LOCKED, &dev->flags) && 2484 !(test_bit(R5_UPTODATE, &dev->flags) || 2485 test_bit(R5_Wantcompute, &dev->flags))) { 2486 if (test_bit(R5_Insync, &dev->flags)) 2487 rmw++; 2488 else 2489 rmw += 2*disks; /* cannot read it */ 2490 } 2491 /* Would I have to read this buffer for reconstruct_write */ 2492 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 2493 !test_bit(R5_LOCKED, &dev->flags) && 2494 !(test_bit(R5_UPTODATE, &dev->flags) || 2495 test_bit(R5_Wantcompute, &dev->flags))) { 2496 if (test_bit(R5_Insync, &dev->flags)) rcw++; 2497 else 2498 rcw += 2*disks; 2499 } 2500 } 2501 pr_debug("for sector %llu, rmw=%d rcw=%d\n", 2502 (unsigned long long)sh->sector, rmw, rcw); 2503 set_bit(STRIPE_HANDLE, &sh->state); 2504 if (rmw < rcw && rmw > 0) 2505 /* prefer read-modify-write, but need to get some data */ 2506 for (i = disks; i--; ) { 2507 struct r5dev *dev = &sh->dev[i]; 2508 if ((dev->towrite || i == sh->pd_idx) && 2509 !test_bit(R5_LOCKED, &dev->flags) && 2510 !(test_bit(R5_UPTODATE, &dev->flags) || 2511 test_bit(R5_Wantcompute, &dev->flags)) && 2512 test_bit(R5_Insync, &dev->flags)) { 2513 if ( 2514 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2515 pr_debug("Read_old block " 2516 "%d for r-m-w\n", i); 2517 set_bit(R5_LOCKED, &dev->flags); 2518 set_bit(R5_Wantread, &dev->flags); 2519 s->locked++; 2520 } else { 2521 set_bit(STRIPE_DELAYED, &sh->state); 2522 set_bit(STRIPE_HANDLE, &sh->state); 2523 } 2524 } 2525 } 2526 if (rcw <= rmw && rcw > 0) 2527 /* want reconstruct write, but need to get some data */ 2528 for (i = disks; i--; ) { 2529 struct r5dev *dev = &sh->dev[i]; 2530 if (!test_bit(R5_OVERWRITE, &dev->flags) && 2531 i != sh->pd_idx && 2532 !test_bit(R5_LOCKED, &dev->flags) && 2533 !(test_bit(R5_UPTODATE, &dev->flags) || 2534 test_bit(R5_Wantcompute, &dev->flags)) && 2535 test_bit(R5_Insync, &dev->flags)) { 2536 if ( 2537 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2538 pr_debug("Read_old block " 2539 "%d for Reconstruct\n", i); 2540 set_bit(R5_LOCKED, &dev->flags); 2541 set_bit(R5_Wantread, &dev->flags); 2542 s->locked++; 2543 } else { 2544 set_bit(STRIPE_DELAYED, &sh->state); 2545 set_bit(STRIPE_HANDLE, &sh->state); 2546 } 2547 } 2548 } 2549 /* now if nothing is locked, and if we have enough data, 2550 * we can start a write request 2551 */ 2552 /* since handle_stripe can be called at any time we need to handle the 2553 * case where a compute block operation has been submitted and then a 2554 * subsequent call wants to start a write request. raid_run_ops only 2555 * handles the case where compute block and reconstruct are requested 2556 * simultaneously. If this is not the case then new writes need to be 2557 * held off until the compute completes. 2558 */ 2559 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) && 2560 (s->locked == 0 && (rcw == 0 || rmw == 0) && 2561 !test_bit(STRIPE_BIT_DELAY, &sh->state))) 2562 schedule_reconstruction(sh, s, rcw == 0, 0); 2563 } 2564 2565 static void handle_stripe_dirtying6(raid5_conf_t *conf, 2566 struct stripe_head *sh, struct stripe_head_state *s, 2567 struct r6_state *r6s, int disks) 2568 { 2569 int rcw = 0, pd_idx = sh->pd_idx, i; 2570 int qd_idx = sh->qd_idx; 2571 2572 set_bit(STRIPE_HANDLE, &sh->state); 2573 for (i = disks; i--; ) { 2574 struct r5dev *dev = &sh->dev[i]; 2575 /* check if we haven't enough data */ 2576 if (!test_bit(R5_OVERWRITE, &dev->flags) && 2577 i != pd_idx && i != qd_idx && 2578 !test_bit(R5_LOCKED, &dev->flags) && 2579 !(test_bit(R5_UPTODATE, &dev->flags) || 2580 test_bit(R5_Wantcompute, &dev->flags))) { 2581 rcw++; 2582 if (!test_bit(R5_Insync, &dev->flags)) 2583 continue; /* it's a failed drive */ 2584 2585 if ( 2586 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2587 pr_debug("Read_old stripe %llu " 2588 "block %d for Reconstruct\n", 2589 (unsigned long long)sh->sector, i); 2590 set_bit(R5_LOCKED, &dev->flags); 2591 set_bit(R5_Wantread, &dev->flags); 2592 s->locked++; 2593 } else { 2594 pr_debug("Request delayed stripe %llu " 2595 "block %d for Reconstruct\n", 2596 (unsigned long long)sh->sector, i); 2597 set_bit(STRIPE_DELAYED, &sh->state); 2598 set_bit(STRIPE_HANDLE, &sh->state); 2599 } 2600 } 2601 } 2602 /* now if nothing is locked, and if we have enough data, we can start a 2603 * write request 2604 */ 2605 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) && 2606 s->locked == 0 && rcw == 0 && 2607 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 2608 schedule_reconstruction(sh, s, 1, 0); 2609 } 2610 } 2611 2612 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh, 2613 struct stripe_head_state *s, int disks) 2614 { 2615 struct r5dev *dev = NULL; 2616 2617 set_bit(STRIPE_HANDLE, &sh->state); 2618 2619 switch (sh->check_state) { 2620 case check_state_idle: 2621 /* start a new check operation if there are no failures */ 2622 if (s->failed == 0) { 2623 BUG_ON(s->uptodate != disks); 2624 sh->check_state = check_state_run; 2625 set_bit(STRIPE_OP_CHECK, &s->ops_request); 2626 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags); 2627 s->uptodate--; 2628 break; 2629 } 2630 dev = &sh->dev[s->failed_num]; 2631 /* fall through */ 2632 case check_state_compute_result: 2633 sh->check_state = check_state_idle; 2634 if (!dev) 2635 dev = &sh->dev[sh->pd_idx]; 2636 2637 /* check that a write has not made the stripe insync */ 2638 if (test_bit(STRIPE_INSYNC, &sh->state)) 2639 break; 2640 2641 /* either failed parity check, or recovery is happening */ 2642 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); 2643 BUG_ON(s->uptodate != disks); 2644 2645 set_bit(R5_LOCKED, &dev->flags); 2646 s->locked++; 2647 set_bit(R5_Wantwrite, &dev->flags); 2648 2649 clear_bit(STRIPE_DEGRADED, &sh->state); 2650 set_bit(STRIPE_INSYNC, &sh->state); 2651 break; 2652 case check_state_run: 2653 break; /* we will be called again upon completion */ 2654 case check_state_check_result: 2655 sh->check_state = check_state_idle; 2656 2657 /* if a failure occurred during the check operation, leave 2658 * STRIPE_INSYNC not set and let the stripe be handled again 2659 */ 2660 if (s->failed) 2661 break; 2662 2663 /* handle a successful check operation, if parity is correct 2664 * we are done. Otherwise update the mismatch count and repair 2665 * parity if !MD_RECOVERY_CHECK 2666 */ 2667 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0) 2668 /* parity is correct (on disc, 2669 * not in buffer any more) 2670 */ 2671 set_bit(STRIPE_INSYNC, &sh->state); 2672 else { 2673 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2674 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2675 /* don't try to repair!! */ 2676 set_bit(STRIPE_INSYNC, &sh->state); 2677 else { 2678 sh->check_state = check_state_compute_run; 2679 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2680 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2681 set_bit(R5_Wantcompute, 2682 &sh->dev[sh->pd_idx].flags); 2683 sh->ops.target = sh->pd_idx; 2684 sh->ops.target2 = -1; 2685 s->uptodate++; 2686 } 2687 } 2688 break; 2689 case check_state_compute_run: 2690 break; 2691 default: 2692 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n", 2693 __func__, sh->check_state, 2694 (unsigned long long) sh->sector); 2695 BUG(); 2696 } 2697 } 2698 2699 2700 static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh, 2701 struct stripe_head_state *s, 2702 struct r6_state *r6s, int disks) 2703 { 2704 int pd_idx = sh->pd_idx; 2705 int qd_idx = sh->qd_idx; 2706 struct r5dev *dev; 2707 2708 set_bit(STRIPE_HANDLE, &sh->state); 2709 2710 BUG_ON(s->failed > 2); 2711 2712 /* Want to check and possibly repair P and Q. 2713 * However there could be one 'failed' device, in which 2714 * case we can only check one of them, possibly using the 2715 * other to generate missing data 2716 */ 2717 2718 switch (sh->check_state) { 2719 case check_state_idle: 2720 /* start a new check operation if there are < 2 failures */ 2721 if (s->failed == r6s->q_failed) { 2722 /* The only possible failed device holds Q, so it 2723 * makes sense to check P (If anything else were failed, 2724 * we would have used P to recreate it). 2725 */ 2726 sh->check_state = check_state_run; 2727 } 2728 if (!r6s->q_failed && s->failed < 2) { 2729 /* Q is not failed, and we didn't use it to generate 2730 * anything, so it makes sense to check it 2731 */ 2732 if (sh->check_state == check_state_run) 2733 sh->check_state = check_state_run_pq; 2734 else 2735 sh->check_state = check_state_run_q; 2736 } 2737 2738 /* discard potentially stale zero_sum_result */ 2739 sh->ops.zero_sum_result = 0; 2740 2741 if (sh->check_state == check_state_run) { 2742 /* async_xor_zero_sum destroys the contents of P */ 2743 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 2744 s->uptodate--; 2745 } 2746 if (sh->check_state >= check_state_run && 2747 sh->check_state <= check_state_run_pq) { 2748 /* async_syndrome_zero_sum preserves P and Q, so 2749 * no need to mark them !uptodate here 2750 */ 2751 set_bit(STRIPE_OP_CHECK, &s->ops_request); 2752 break; 2753 } 2754 2755 /* we have 2-disk failure */ 2756 BUG_ON(s->failed != 2); 2757 /* fall through */ 2758 case check_state_compute_result: 2759 sh->check_state = check_state_idle; 2760 2761 /* check that a write has not made the stripe insync */ 2762 if (test_bit(STRIPE_INSYNC, &sh->state)) 2763 break; 2764 2765 /* now write out any block on a failed drive, 2766 * or P or Q if they were recomputed 2767 */ 2768 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */ 2769 if (s->failed == 2) { 2770 dev = &sh->dev[r6s->failed_num[1]]; 2771 s->locked++; 2772 set_bit(R5_LOCKED, &dev->flags); 2773 set_bit(R5_Wantwrite, &dev->flags); 2774 } 2775 if (s->failed >= 1) { 2776 dev = &sh->dev[r6s->failed_num[0]]; 2777 s->locked++; 2778 set_bit(R5_LOCKED, &dev->flags); 2779 set_bit(R5_Wantwrite, &dev->flags); 2780 } 2781 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) { 2782 dev = &sh->dev[pd_idx]; 2783 s->locked++; 2784 set_bit(R5_LOCKED, &dev->flags); 2785 set_bit(R5_Wantwrite, &dev->flags); 2786 } 2787 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) { 2788 dev = &sh->dev[qd_idx]; 2789 s->locked++; 2790 set_bit(R5_LOCKED, &dev->flags); 2791 set_bit(R5_Wantwrite, &dev->flags); 2792 } 2793 clear_bit(STRIPE_DEGRADED, &sh->state); 2794 2795 set_bit(STRIPE_INSYNC, &sh->state); 2796 break; 2797 case check_state_run: 2798 case check_state_run_q: 2799 case check_state_run_pq: 2800 break; /* we will be called again upon completion */ 2801 case check_state_check_result: 2802 sh->check_state = check_state_idle; 2803 2804 /* handle a successful check operation, if parity is correct 2805 * we are done. Otherwise update the mismatch count and repair 2806 * parity if !MD_RECOVERY_CHECK 2807 */ 2808 if (sh->ops.zero_sum_result == 0) { 2809 /* both parities are correct */ 2810 if (!s->failed) 2811 set_bit(STRIPE_INSYNC, &sh->state); 2812 else { 2813 /* in contrast to the raid5 case we can validate 2814 * parity, but still have a failure to write 2815 * back 2816 */ 2817 sh->check_state = check_state_compute_result; 2818 /* Returning at this point means that we may go 2819 * off and bring p and/or q uptodate again so 2820 * we make sure to check zero_sum_result again 2821 * to verify if p or q need writeback 2822 */ 2823 } 2824 } else { 2825 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2826 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2827 /* don't try to repair!! */ 2828 set_bit(STRIPE_INSYNC, &sh->state); 2829 else { 2830 int *target = &sh->ops.target; 2831 2832 sh->ops.target = -1; 2833 sh->ops.target2 = -1; 2834 sh->check_state = check_state_compute_run; 2835 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2836 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2837 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) { 2838 set_bit(R5_Wantcompute, 2839 &sh->dev[pd_idx].flags); 2840 *target = pd_idx; 2841 target = &sh->ops.target2; 2842 s->uptodate++; 2843 } 2844 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) { 2845 set_bit(R5_Wantcompute, 2846 &sh->dev[qd_idx].flags); 2847 *target = qd_idx; 2848 s->uptodate++; 2849 } 2850 } 2851 } 2852 break; 2853 case check_state_compute_run: 2854 break; 2855 default: 2856 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n", 2857 __func__, sh->check_state, 2858 (unsigned long long) sh->sector); 2859 BUG(); 2860 } 2861 } 2862 2863 static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, 2864 struct r6_state *r6s) 2865 { 2866 int i; 2867 2868 /* We have read all the blocks in this stripe and now we need to 2869 * copy some of them into a target stripe for expand. 2870 */ 2871 struct dma_async_tx_descriptor *tx = NULL; 2872 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2873 for (i = 0; i < sh->disks; i++) 2874 if (i != sh->pd_idx && i != sh->qd_idx) { 2875 int dd_idx, j; 2876 struct stripe_head *sh2; 2877 struct async_submit_ctl submit; 2878 2879 sector_t bn = compute_blocknr(sh, i, 1); 2880 sector_t s = raid5_compute_sector(conf, bn, 0, 2881 &dd_idx, NULL); 2882 sh2 = get_active_stripe(conf, s, 0, 1, 1); 2883 if (sh2 == NULL) 2884 /* so far only the early blocks of this stripe 2885 * have been requested. When later blocks 2886 * get requested, we will try again 2887 */ 2888 continue; 2889 if (!test_bit(STRIPE_EXPANDING, &sh2->state) || 2890 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) { 2891 /* must have already done this block */ 2892 release_stripe(sh2); 2893 continue; 2894 } 2895 2896 /* place all the copies on one channel */ 2897 init_async_submit(&submit, 0, tx, NULL, NULL, NULL); 2898 tx = async_memcpy(sh2->dev[dd_idx].page, 2899 sh->dev[i].page, 0, 0, STRIPE_SIZE, 2900 &submit); 2901 2902 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags); 2903 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags); 2904 for (j = 0; j < conf->raid_disks; j++) 2905 if (j != sh2->pd_idx && 2906 (!r6s || j != sh2->qd_idx) && 2907 !test_bit(R5_Expanded, &sh2->dev[j].flags)) 2908 break; 2909 if (j == conf->raid_disks) { 2910 set_bit(STRIPE_EXPAND_READY, &sh2->state); 2911 set_bit(STRIPE_HANDLE, &sh2->state); 2912 } 2913 release_stripe(sh2); 2914 2915 } 2916 /* done submitting copies, wait for them to complete */ 2917 if (tx) { 2918 async_tx_ack(tx); 2919 dma_wait_for_async_tx(tx); 2920 } 2921 } 2922 2923 2924 /* 2925 * handle_stripe - do things to a stripe. 2926 * 2927 * We lock the stripe and then examine the state of various bits 2928 * to see what needs to be done. 2929 * Possible results: 2930 * return some read request which now have data 2931 * return some write requests which are safely on disc 2932 * schedule a read on some buffers 2933 * schedule a write of some buffers 2934 * return confirmation of parity correctness 2935 * 2936 * buffers are taken off read_list or write_list, and bh_cache buffers 2937 * get BH_Lock set before the stripe lock is released. 2938 * 2939 */ 2940 2941 static void handle_stripe5(struct stripe_head *sh) 2942 { 2943 raid5_conf_t *conf = sh->raid_conf; 2944 int disks = sh->disks, i; 2945 struct bio *return_bi = NULL; 2946 struct stripe_head_state s; 2947 struct r5dev *dev; 2948 mdk_rdev_t *blocked_rdev = NULL; 2949 int prexor; 2950 2951 memset(&s, 0, sizeof(s)); 2952 pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d " 2953 "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state, 2954 atomic_read(&sh->count), sh->pd_idx, sh->check_state, 2955 sh->reconstruct_state); 2956 2957 spin_lock(&sh->lock); 2958 clear_bit(STRIPE_HANDLE, &sh->state); 2959 clear_bit(STRIPE_DELAYED, &sh->state); 2960 2961 s.syncing = test_bit(STRIPE_SYNCING, &sh->state); 2962 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2963 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 2964 2965 /* Now to look around and see what can be done */ 2966 rcu_read_lock(); 2967 for (i=disks; i--; ) { 2968 mdk_rdev_t *rdev; 2969 2970 dev = &sh->dev[i]; 2971 clear_bit(R5_Insync, &dev->flags); 2972 2973 pr_debug("check %d: state 0x%lx toread %p read %p write %p " 2974 "written %p\n", i, dev->flags, dev->toread, dev->read, 2975 dev->towrite, dev->written); 2976 2977 /* maybe we can request a biofill operation 2978 * 2979 * new wantfill requests are only permitted while 2980 * ops_complete_biofill is guaranteed to be inactive 2981 */ 2982 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && 2983 !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) 2984 set_bit(R5_Wantfill, &dev->flags); 2985 2986 /* now count some things */ 2987 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; 2988 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; 2989 if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++; 2990 2991 if (test_bit(R5_Wantfill, &dev->flags)) 2992 s.to_fill++; 2993 else if (dev->toread) 2994 s.to_read++; 2995 if (dev->towrite) { 2996 s.to_write++; 2997 if (!test_bit(R5_OVERWRITE, &dev->flags)) 2998 s.non_overwrite++; 2999 } 3000 if (dev->written) 3001 s.written++; 3002 rdev = rcu_dereference(conf->disks[i].rdev); 3003 if (blocked_rdev == NULL && 3004 rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 3005 blocked_rdev = rdev; 3006 atomic_inc(&rdev->nr_pending); 3007 } 3008 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 3009 /* The ReadError flag will just be confusing now */ 3010 clear_bit(R5_ReadError, &dev->flags); 3011 clear_bit(R5_ReWrite, &dev->flags); 3012 } 3013 if (!rdev || !test_bit(In_sync, &rdev->flags) 3014 || test_bit(R5_ReadError, &dev->flags)) { 3015 s.failed++; 3016 s.failed_num = i; 3017 } else 3018 set_bit(R5_Insync, &dev->flags); 3019 } 3020 rcu_read_unlock(); 3021 3022 if (unlikely(blocked_rdev)) { 3023 if (s.syncing || s.expanding || s.expanded || 3024 s.to_write || s.written) { 3025 set_bit(STRIPE_HANDLE, &sh->state); 3026 goto unlock; 3027 } 3028 /* There is nothing for the blocked_rdev to block */ 3029 rdev_dec_pending(blocked_rdev, conf->mddev); 3030 blocked_rdev = NULL; 3031 } 3032 3033 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) { 3034 set_bit(STRIPE_OP_BIOFILL, &s.ops_request); 3035 set_bit(STRIPE_BIOFILL_RUN, &sh->state); 3036 } 3037 3038 pr_debug("locked=%d uptodate=%d to_read=%d" 3039 " to_write=%d failed=%d failed_num=%d\n", 3040 s.locked, s.uptodate, s.to_read, s.to_write, 3041 s.failed, s.failed_num); 3042 /* check if the array has lost two devices and, if so, some requests might 3043 * need to be failed 3044 */ 3045 if (s.failed > 1 && s.to_read+s.to_write+s.written) 3046 handle_failed_stripe(conf, sh, &s, disks, &return_bi); 3047 if (s.failed > 1 && s.syncing) { 3048 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 3049 clear_bit(STRIPE_SYNCING, &sh->state); 3050 s.syncing = 0; 3051 } 3052 3053 /* might be able to return some write requests if the parity block 3054 * is safe, or on a failed drive 3055 */ 3056 dev = &sh->dev[sh->pd_idx]; 3057 if ( s.written && 3058 ((test_bit(R5_Insync, &dev->flags) && 3059 !test_bit(R5_LOCKED, &dev->flags) && 3060 test_bit(R5_UPTODATE, &dev->flags)) || 3061 (s.failed == 1 && s.failed_num == sh->pd_idx))) 3062 handle_stripe_clean_event(conf, sh, disks, &return_bi); 3063 3064 /* Now we might consider reading some blocks, either to check/generate 3065 * parity, or to satisfy requests 3066 * or to load a block that is being partially written. 3067 */ 3068 if (s.to_read || s.non_overwrite || 3069 (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding) 3070 handle_stripe_fill5(sh, &s, disks); 3071 3072 /* Now we check to see if any write operations have recently 3073 * completed 3074 */ 3075 prexor = 0; 3076 if (sh->reconstruct_state == reconstruct_state_prexor_drain_result) 3077 prexor = 1; 3078 if (sh->reconstruct_state == reconstruct_state_drain_result || 3079 sh->reconstruct_state == reconstruct_state_prexor_drain_result) { 3080 sh->reconstruct_state = reconstruct_state_idle; 3081 3082 /* All the 'written' buffers and the parity block are ready to 3083 * be written back to disk 3084 */ 3085 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); 3086 for (i = disks; i--; ) { 3087 dev = &sh->dev[i]; 3088 if (test_bit(R5_LOCKED, &dev->flags) && 3089 (i == sh->pd_idx || dev->written)) { 3090 pr_debug("Writing block %d\n", i); 3091 set_bit(R5_Wantwrite, &dev->flags); 3092 if (prexor) 3093 continue; 3094 if (!test_bit(R5_Insync, &dev->flags) || 3095 (i == sh->pd_idx && s.failed == 0)) 3096 set_bit(STRIPE_INSYNC, &sh->state); 3097 } 3098 } 3099 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 3100 atomic_dec(&conf->preread_active_stripes); 3101 if (atomic_read(&conf->preread_active_stripes) < 3102 IO_THRESHOLD) 3103 md_wakeup_thread(conf->mddev->thread); 3104 } 3105 } 3106 3107 /* Now to consider new write requests and what else, if anything 3108 * should be read. We do not handle new writes when: 3109 * 1/ A 'write' operation (copy+xor) is already in flight. 3110 * 2/ A 'check' operation is in flight, as it may clobber the parity 3111 * block. 3112 */ 3113 if (s.to_write && !sh->reconstruct_state && !sh->check_state) 3114 handle_stripe_dirtying5(conf, sh, &s, disks); 3115 3116 /* maybe we need to check and possibly fix the parity for this stripe 3117 * Any reads will already have been scheduled, so we just see if enough 3118 * data is available. The parity check is held off while parity 3119 * dependent operations are in flight. 3120 */ 3121 if (sh->check_state || 3122 (s.syncing && s.locked == 0 && 3123 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) && 3124 !test_bit(STRIPE_INSYNC, &sh->state))) 3125 handle_parity_checks5(conf, sh, &s, disks); 3126 3127 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 3128 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 3129 clear_bit(STRIPE_SYNCING, &sh->state); 3130 } 3131 3132 /* If the failed drive is just a ReadError, then we might need to progress 3133 * the repair/check process 3134 */ 3135 if (s.failed == 1 && !conf->mddev->ro && 3136 test_bit(R5_ReadError, &sh->dev[s.failed_num].flags) 3137 && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags) 3138 && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags) 3139 ) { 3140 dev = &sh->dev[s.failed_num]; 3141 if (!test_bit(R5_ReWrite, &dev->flags)) { 3142 set_bit(R5_Wantwrite, &dev->flags); 3143 set_bit(R5_ReWrite, &dev->flags); 3144 set_bit(R5_LOCKED, &dev->flags); 3145 s.locked++; 3146 } else { 3147 /* let's read it back */ 3148 set_bit(R5_Wantread, &dev->flags); 3149 set_bit(R5_LOCKED, &dev->flags); 3150 s.locked++; 3151 } 3152 } 3153 3154 /* Finish reconstruct operations initiated by the expansion process */ 3155 if (sh->reconstruct_state == reconstruct_state_result) { 3156 struct stripe_head *sh2 3157 = get_active_stripe(conf, sh->sector, 1, 1, 1); 3158 if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) { 3159 /* sh cannot be written until sh2 has been read. 3160 * so arrange for sh to be delayed a little 3161 */ 3162 set_bit(STRIPE_DELAYED, &sh->state); 3163 set_bit(STRIPE_HANDLE, &sh->state); 3164 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, 3165 &sh2->state)) 3166 atomic_inc(&conf->preread_active_stripes); 3167 release_stripe(sh2); 3168 goto unlock; 3169 } 3170 if (sh2) 3171 release_stripe(sh2); 3172 3173 sh->reconstruct_state = reconstruct_state_idle; 3174 clear_bit(STRIPE_EXPANDING, &sh->state); 3175 for (i = conf->raid_disks; i--; ) { 3176 set_bit(R5_Wantwrite, &sh->dev[i].flags); 3177 set_bit(R5_LOCKED, &sh->dev[i].flags); 3178 s.locked++; 3179 } 3180 } 3181 3182 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) && 3183 !sh->reconstruct_state) { 3184 /* Need to write out all blocks after computing parity */ 3185 sh->disks = conf->raid_disks; 3186 stripe_set_idx(sh->sector, conf, 0, sh); 3187 schedule_reconstruction(sh, &s, 1, 1); 3188 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) { 3189 clear_bit(STRIPE_EXPAND_READY, &sh->state); 3190 atomic_dec(&conf->reshape_stripes); 3191 wake_up(&conf->wait_for_overlap); 3192 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 3193 } 3194 3195 if (s.expanding && s.locked == 0 && 3196 !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) 3197 handle_stripe_expansion(conf, sh, NULL); 3198 3199 unlock: 3200 spin_unlock(&sh->lock); 3201 3202 /* wait for this device to become unblocked */ 3203 if (unlikely(blocked_rdev)) 3204 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); 3205 3206 if (s.ops_request) 3207 raid_run_ops(sh, s.ops_request); 3208 3209 ops_run_io(sh, &s); 3210 3211 return_io(return_bi); 3212 } 3213 3214 static void handle_stripe6(struct stripe_head *sh) 3215 { 3216 raid5_conf_t *conf = sh->raid_conf; 3217 int disks = sh->disks; 3218 struct bio *return_bi = NULL; 3219 int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx; 3220 struct stripe_head_state s; 3221 struct r6_state r6s; 3222 struct r5dev *dev, *pdev, *qdev; 3223 mdk_rdev_t *blocked_rdev = NULL; 3224 3225 pr_debug("handling stripe %llu, state=%#lx cnt=%d, " 3226 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n", 3227 (unsigned long long)sh->sector, sh->state, 3228 atomic_read(&sh->count), pd_idx, qd_idx, 3229 sh->check_state, sh->reconstruct_state); 3230 memset(&s, 0, sizeof(s)); 3231 3232 spin_lock(&sh->lock); 3233 clear_bit(STRIPE_HANDLE, &sh->state); 3234 clear_bit(STRIPE_DELAYED, &sh->state); 3235 3236 s.syncing = test_bit(STRIPE_SYNCING, &sh->state); 3237 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 3238 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 3239 /* Now to look around and see what can be done */ 3240 3241 rcu_read_lock(); 3242 for (i=disks; i--; ) { 3243 mdk_rdev_t *rdev; 3244 dev = &sh->dev[i]; 3245 clear_bit(R5_Insync, &dev->flags); 3246 3247 pr_debug("check %d: state 0x%lx read %p write %p written %p\n", 3248 i, dev->flags, dev->toread, dev->towrite, dev->written); 3249 /* maybe we can reply to a read 3250 * 3251 * new wantfill requests are only permitted while 3252 * ops_complete_biofill is guaranteed to be inactive 3253 */ 3254 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && 3255 !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) 3256 set_bit(R5_Wantfill, &dev->flags); 3257 3258 /* now count some things */ 3259 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; 3260 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; 3261 if (test_bit(R5_Wantcompute, &dev->flags)) { 3262 s.compute++; 3263 BUG_ON(s.compute > 2); 3264 } 3265 3266 if (test_bit(R5_Wantfill, &dev->flags)) { 3267 s.to_fill++; 3268 } else if (dev->toread) 3269 s.to_read++; 3270 if (dev->towrite) { 3271 s.to_write++; 3272 if (!test_bit(R5_OVERWRITE, &dev->flags)) 3273 s.non_overwrite++; 3274 } 3275 if (dev->written) 3276 s.written++; 3277 rdev = rcu_dereference(conf->disks[i].rdev); 3278 if (blocked_rdev == NULL && 3279 rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 3280 blocked_rdev = rdev; 3281 atomic_inc(&rdev->nr_pending); 3282 } 3283 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 3284 /* The ReadError flag will just be confusing now */ 3285 clear_bit(R5_ReadError, &dev->flags); 3286 clear_bit(R5_ReWrite, &dev->flags); 3287 } 3288 if (!rdev || !test_bit(In_sync, &rdev->flags) 3289 || test_bit(R5_ReadError, &dev->flags)) { 3290 if (s.failed < 2) 3291 r6s.failed_num[s.failed] = i; 3292 s.failed++; 3293 } else 3294 set_bit(R5_Insync, &dev->flags); 3295 } 3296 rcu_read_unlock(); 3297 3298 if (unlikely(blocked_rdev)) { 3299 if (s.syncing || s.expanding || s.expanded || 3300 s.to_write || s.written) { 3301 set_bit(STRIPE_HANDLE, &sh->state); 3302 goto unlock; 3303 } 3304 /* There is nothing for the blocked_rdev to block */ 3305 rdev_dec_pending(blocked_rdev, conf->mddev); 3306 blocked_rdev = NULL; 3307 } 3308 3309 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) { 3310 set_bit(STRIPE_OP_BIOFILL, &s.ops_request); 3311 set_bit(STRIPE_BIOFILL_RUN, &sh->state); 3312 } 3313 3314 pr_debug("locked=%d uptodate=%d to_read=%d" 3315 " to_write=%d failed=%d failed_num=%d,%d\n", 3316 s.locked, s.uptodate, s.to_read, s.to_write, s.failed, 3317 r6s.failed_num[0], r6s.failed_num[1]); 3318 /* check if the array has lost >2 devices and, if so, some requests 3319 * might need to be failed 3320 */ 3321 if (s.failed > 2 && s.to_read+s.to_write+s.written) 3322 handle_failed_stripe(conf, sh, &s, disks, &return_bi); 3323 if (s.failed > 2 && s.syncing) { 3324 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 3325 clear_bit(STRIPE_SYNCING, &sh->state); 3326 s.syncing = 0; 3327 } 3328 3329 /* 3330 * might be able to return some write requests if the parity blocks 3331 * are safe, or on a failed drive 3332 */ 3333 pdev = &sh->dev[pd_idx]; 3334 r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx) 3335 || (s.failed >= 2 && r6s.failed_num[1] == pd_idx); 3336 qdev = &sh->dev[qd_idx]; 3337 r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == qd_idx) 3338 || (s.failed >= 2 && r6s.failed_num[1] == qd_idx); 3339 3340 if ( s.written && 3341 ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags) 3342 && !test_bit(R5_LOCKED, &pdev->flags) 3343 && test_bit(R5_UPTODATE, &pdev->flags)))) && 3344 ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags) 3345 && !test_bit(R5_LOCKED, &qdev->flags) 3346 && test_bit(R5_UPTODATE, &qdev->flags))))) 3347 handle_stripe_clean_event(conf, sh, disks, &return_bi); 3348 3349 /* Now we might consider reading some blocks, either to check/generate 3350 * parity, or to satisfy requests 3351 * or to load a block that is being partially written. 3352 */ 3353 if (s.to_read || s.non_overwrite || (s.to_write && s.failed) || 3354 (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding) 3355 handle_stripe_fill6(sh, &s, &r6s, disks); 3356 3357 /* Now we check to see if any write operations have recently 3358 * completed 3359 */ 3360 if (sh->reconstruct_state == reconstruct_state_drain_result) { 3361 int qd_idx = sh->qd_idx; 3362 3363 sh->reconstruct_state = reconstruct_state_idle; 3364 /* All the 'written' buffers and the parity blocks are ready to 3365 * be written back to disk 3366 */ 3367 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); 3368 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags)); 3369 for (i = disks; i--; ) { 3370 dev = &sh->dev[i]; 3371 if (test_bit(R5_LOCKED, &dev->flags) && 3372 (i == sh->pd_idx || i == qd_idx || 3373 dev->written)) { 3374 pr_debug("Writing block %d\n", i); 3375 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); 3376 set_bit(R5_Wantwrite, &dev->flags); 3377 if (!test_bit(R5_Insync, &dev->flags) || 3378 ((i == sh->pd_idx || i == qd_idx) && 3379 s.failed == 0)) 3380 set_bit(STRIPE_INSYNC, &sh->state); 3381 } 3382 } 3383 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 3384 atomic_dec(&conf->preread_active_stripes); 3385 if (atomic_read(&conf->preread_active_stripes) < 3386 IO_THRESHOLD) 3387 md_wakeup_thread(conf->mddev->thread); 3388 } 3389 } 3390 3391 /* Now to consider new write requests and what else, if anything 3392 * should be read. We do not handle new writes when: 3393 * 1/ A 'write' operation (copy+gen_syndrome) is already in flight. 3394 * 2/ A 'check' operation is in flight, as it may clobber the parity 3395 * block. 3396 */ 3397 if (s.to_write && !sh->reconstruct_state && !sh->check_state) 3398 handle_stripe_dirtying6(conf, sh, &s, &r6s, disks); 3399 3400 /* maybe we need to check and possibly fix the parity for this stripe 3401 * Any reads will already have been scheduled, so we just see if enough 3402 * data is available. The parity check is held off while parity 3403 * dependent operations are in flight. 3404 */ 3405 if (sh->check_state || 3406 (s.syncing && s.locked == 0 && 3407 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) && 3408 !test_bit(STRIPE_INSYNC, &sh->state))) 3409 handle_parity_checks6(conf, sh, &s, &r6s, disks); 3410 3411 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 3412 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 3413 clear_bit(STRIPE_SYNCING, &sh->state); 3414 } 3415 3416 /* If the failed drives are just a ReadError, then we might need 3417 * to progress the repair/check process 3418 */ 3419 if (s.failed <= 2 && !conf->mddev->ro) 3420 for (i = 0; i < s.failed; i++) { 3421 dev = &sh->dev[r6s.failed_num[i]]; 3422 if (test_bit(R5_ReadError, &dev->flags) 3423 && !test_bit(R5_LOCKED, &dev->flags) 3424 && test_bit(R5_UPTODATE, &dev->flags) 3425 ) { 3426 if (!test_bit(R5_ReWrite, &dev->flags)) { 3427 set_bit(R5_Wantwrite, &dev->flags); 3428 set_bit(R5_ReWrite, &dev->flags); 3429 set_bit(R5_LOCKED, &dev->flags); 3430 s.locked++; 3431 } else { 3432 /* let's read it back */ 3433 set_bit(R5_Wantread, &dev->flags); 3434 set_bit(R5_LOCKED, &dev->flags); 3435 s.locked++; 3436 } 3437 } 3438 } 3439 3440 /* Finish reconstruct operations initiated by the expansion process */ 3441 if (sh->reconstruct_state == reconstruct_state_result) { 3442 sh->reconstruct_state = reconstruct_state_idle; 3443 clear_bit(STRIPE_EXPANDING, &sh->state); 3444 for (i = conf->raid_disks; i--; ) { 3445 set_bit(R5_Wantwrite, &sh->dev[i].flags); 3446 set_bit(R5_LOCKED, &sh->dev[i].flags); 3447 s.locked++; 3448 } 3449 } 3450 3451 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) && 3452 !sh->reconstruct_state) { 3453 struct stripe_head *sh2 3454 = get_active_stripe(conf, sh->sector, 1, 1, 1); 3455 if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) { 3456 /* sh cannot be written until sh2 has been read. 3457 * so arrange for sh to be delayed a little 3458 */ 3459 set_bit(STRIPE_DELAYED, &sh->state); 3460 set_bit(STRIPE_HANDLE, &sh->state); 3461 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, 3462 &sh2->state)) 3463 atomic_inc(&conf->preread_active_stripes); 3464 release_stripe(sh2); 3465 goto unlock; 3466 } 3467 if (sh2) 3468 release_stripe(sh2); 3469 3470 /* Need to write out all blocks after computing P&Q */ 3471 sh->disks = conf->raid_disks; 3472 stripe_set_idx(sh->sector, conf, 0, sh); 3473 schedule_reconstruction(sh, &s, 1, 1); 3474 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) { 3475 clear_bit(STRIPE_EXPAND_READY, &sh->state); 3476 atomic_dec(&conf->reshape_stripes); 3477 wake_up(&conf->wait_for_overlap); 3478 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 3479 } 3480 3481 if (s.expanding && s.locked == 0 && 3482 !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) 3483 handle_stripe_expansion(conf, sh, &r6s); 3484 3485 unlock: 3486 spin_unlock(&sh->lock); 3487 3488 /* wait for this device to become unblocked */ 3489 if (unlikely(blocked_rdev)) 3490 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); 3491 3492 if (s.ops_request) 3493 raid_run_ops(sh, s.ops_request); 3494 3495 ops_run_io(sh, &s); 3496 3497 return_io(return_bi); 3498 } 3499 3500 static void handle_stripe(struct stripe_head *sh) 3501 { 3502 if (sh->raid_conf->level == 6) 3503 handle_stripe6(sh); 3504 else 3505 handle_stripe5(sh); 3506 } 3507 3508 static void raid5_activate_delayed(raid5_conf_t *conf) 3509 { 3510 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { 3511 while (!list_empty(&conf->delayed_list)) { 3512 struct list_head *l = conf->delayed_list.next; 3513 struct stripe_head *sh; 3514 sh = list_entry(l, struct stripe_head, lru); 3515 list_del_init(l); 3516 clear_bit(STRIPE_DELAYED, &sh->state); 3517 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 3518 atomic_inc(&conf->preread_active_stripes); 3519 list_add_tail(&sh->lru, &conf->hold_list); 3520 } 3521 } else 3522 blk_plug_device(conf->mddev->queue); 3523 } 3524 3525 static void activate_bit_delay(raid5_conf_t *conf) 3526 { 3527 /* device_lock is held */ 3528 struct list_head head; 3529 list_add(&head, &conf->bitmap_list); 3530 list_del_init(&conf->bitmap_list); 3531 while (!list_empty(&head)) { 3532 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); 3533 list_del_init(&sh->lru); 3534 atomic_inc(&sh->count); 3535 __release_stripe(conf, sh); 3536 } 3537 } 3538 3539 static void unplug_slaves(mddev_t *mddev) 3540 { 3541 raid5_conf_t *conf = mddev->private; 3542 int i; 3543 int devs = max(conf->raid_disks, conf->previous_raid_disks); 3544 3545 rcu_read_lock(); 3546 for (i = 0; i < devs; i++) { 3547 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 3548 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 3549 struct request_queue *r_queue = bdev_get_queue(rdev->bdev); 3550 3551 atomic_inc(&rdev->nr_pending); 3552 rcu_read_unlock(); 3553 3554 blk_unplug(r_queue); 3555 3556 rdev_dec_pending(rdev, mddev); 3557 rcu_read_lock(); 3558 } 3559 } 3560 rcu_read_unlock(); 3561 } 3562 3563 static void raid5_unplug_device(struct request_queue *q) 3564 { 3565 mddev_t *mddev = q->queuedata; 3566 raid5_conf_t *conf = mddev->private; 3567 unsigned long flags; 3568 3569 spin_lock_irqsave(&conf->device_lock, flags); 3570 3571 if (blk_remove_plug(q)) { 3572 conf->seq_flush++; 3573 raid5_activate_delayed(conf); 3574 } 3575 md_wakeup_thread(mddev->thread); 3576 3577 spin_unlock_irqrestore(&conf->device_lock, flags); 3578 3579 unplug_slaves(mddev); 3580 } 3581 3582 static int raid5_congested(void *data, int bits) 3583 { 3584 mddev_t *mddev = data; 3585 raid5_conf_t *conf = mddev->private; 3586 3587 /* No difference between reads and writes. Just check 3588 * how busy the stripe_cache is 3589 */ 3590 3591 if (mddev_congested(mddev, bits)) 3592 return 1; 3593 if (conf->inactive_blocked) 3594 return 1; 3595 if (conf->quiesce) 3596 return 1; 3597 if (list_empty_careful(&conf->inactive_list)) 3598 return 1; 3599 3600 return 0; 3601 } 3602 3603 /* We want read requests to align with chunks where possible, 3604 * but write requests don't need to. 3605 */ 3606 static int raid5_mergeable_bvec(struct request_queue *q, 3607 struct bvec_merge_data *bvm, 3608 struct bio_vec *biovec) 3609 { 3610 mddev_t *mddev = q->queuedata; 3611 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 3612 int max; 3613 unsigned int chunk_sectors = mddev->chunk_sectors; 3614 unsigned int bio_sectors = bvm->bi_size >> 9; 3615 3616 if ((bvm->bi_rw & 1) == WRITE) 3617 return biovec->bv_len; /* always allow writes to be mergeable */ 3618 3619 if (mddev->new_chunk_sectors < mddev->chunk_sectors) 3620 chunk_sectors = mddev->new_chunk_sectors; 3621 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; 3622 if (max < 0) max = 0; 3623 if (max <= biovec->bv_len && bio_sectors == 0) 3624 return biovec->bv_len; 3625 else 3626 return max; 3627 } 3628 3629 3630 static int in_chunk_boundary(mddev_t *mddev, struct bio *bio) 3631 { 3632 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); 3633 unsigned int chunk_sectors = mddev->chunk_sectors; 3634 unsigned int bio_sectors = bio->bi_size >> 9; 3635 3636 if (mddev->new_chunk_sectors < mddev->chunk_sectors) 3637 chunk_sectors = mddev->new_chunk_sectors; 3638 return chunk_sectors >= 3639 ((sector & (chunk_sectors - 1)) + bio_sectors); 3640 } 3641 3642 /* 3643 * add bio to the retry LIFO ( in O(1) ... we are in interrupt ) 3644 * later sampled by raid5d. 3645 */ 3646 static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf) 3647 { 3648 unsigned long flags; 3649 3650 spin_lock_irqsave(&conf->device_lock, flags); 3651 3652 bi->bi_next = conf->retry_read_aligned_list; 3653 conf->retry_read_aligned_list = bi; 3654 3655 spin_unlock_irqrestore(&conf->device_lock, flags); 3656 md_wakeup_thread(conf->mddev->thread); 3657 } 3658 3659 3660 static struct bio *remove_bio_from_retry(raid5_conf_t *conf) 3661 { 3662 struct bio *bi; 3663 3664 bi = conf->retry_read_aligned; 3665 if (bi) { 3666 conf->retry_read_aligned = NULL; 3667 return bi; 3668 } 3669 bi = conf->retry_read_aligned_list; 3670 if(bi) { 3671 conf->retry_read_aligned_list = bi->bi_next; 3672 bi->bi_next = NULL; 3673 /* 3674 * this sets the active strip count to 1 and the processed 3675 * strip count to zero (upper 8 bits) 3676 */ 3677 bi->bi_phys_segments = 1; /* biased count of active stripes */ 3678 } 3679 3680 return bi; 3681 } 3682 3683 3684 /* 3685 * The "raid5_align_endio" should check if the read succeeded and if it 3686 * did, call bio_endio on the original bio (having bio_put the new bio 3687 * first). 3688 * If the read failed.. 3689 */ 3690 static void raid5_align_endio(struct bio *bi, int error) 3691 { 3692 struct bio* raid_bi = bi->bi_private; 3693 mddev_t *mddev; 3694 raid5_conf_t *conf; 3695 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 3696 mdk_rdev_t *rdev; 3697 3698 bio_put(bi); 3699 3700 mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata; 3701 conf = mddev->private; 3702 rdev = (void*)raid_bi->bi_next; 3703 raid_bi->bi_next = NULL; 3704 3705 rdev_dec_pending(rdev, conf->mddev); 3706 3707 if (!error && uptodate) { 3708 bio_endio(raid_bi, 0); 3709 if (atomic_dec_and_test(&conf->active_aligned_reads)) 3710 wake_up(&conf->wait_for_stripe); 3711 return; 3712 } 3713 3714 3715 pr_debug("raid5_align_endio : io error...handing IO for a retry\n"); 3716 3717 add_bio_to_retry(raid_bi, conf); 3718 } 3719 3720 static int bio_fits_rdev(struct bio *bi) 3721 { 3722 struct request_queue *q = bdev_get_queue(bi->bi_bdev); 3723 3724 if ((bi->bi_size>>9) > queue_max_sectors(q)) 3725 return 0; 3726 blk_recount_segments(q, bi); 3727 if (bi->bi_phys_segments > queue_max_phys_segments(q)) 3728 return 0; 3729 3730 if (q->merge_bvec_fn) 3731 /* it's too hard to apply the merge_bvec_fn at this stage, 3732 * just just give up 3733 */ 3734 return 0; 3735 3736 return 1; 3737 } 3738 3739 3740 static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio) 3741 { 3742 mddev_t *mddev = q->queuedata; 3743 raid5_conf_t *conf = mddev->private; 3744 unsigned int dd_idx; 3745 struct bio* align_bi; 3746 mdk_rdev_t *rdev; 3747 3748 if (!in_chunk_boundary(mddev, raid_bio)) { 3749 pr_debug("chunk_aligned_read : non aligned\n"); 3750 return 0; 3751 } 3752 /* 3753 * use bio_clone to make a copy of the bio 3754 */ 3755 align_bi = bio_clone(raid_bio, GFP_NOIO); 3756 if (!align_bi) 3757 return 0; 3758 /* 3759 * set bi_end_io to a new function, and set bi_private to the 3760 * original bio. 3761 */ 3762 align_bi->bi_end_io = raid5_align_endio; 3763 align_bi->bi_private = raid_bio; 3764 /* 3765 * compute position 3766 */ 3767 align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector, 3768 0, 3769 &dd_idx, NULL); 3770 3771 rcu_read_lock(); 3772 rdev = rcu_dereference(conf->disks[dd_idx].rdev); 3773 if (rdev && test_bit(In_sync, &rdev->flags)) { 3774 atomic_inc(&rdev->nr_pending); 3775 rcu_read_unlock(); 3776 raid_bio->bi_next = (void*)rdev; 3777 align_bi->bi_bdev = rdev->bdev; 3778 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID); 3779 align_bi->bi_sector += rdev->data_offset; 3780 3781 if (!bio_fits_rdev(align_bi)) { 3782 /* too big in some way */ 3783 bio_put(align_bi); 3784 rdev_dec_pending(rdev, mddev); 3785 return 0; 3786 } 3787 3788 spin_lock_irq(&conf->device_lock); 3789 wait_event_lock_irq(conf->wait_for_stripe, 3790 conf->quiesce == 0, 3791 conf->device_lock, /* nothing */); 3792 atomic_inc(&conf->active_aligned_reads); 3793 spin_unlock_irq(&conf->device_lock); 3794 3795 generic_make_request(align_bi); 3796 return 1; 3797 } else { 3798 rcu_read_unlock(); 3799 bio_put(align_bi); 3800 return 0; 3801 } 3802 } 3803 3804 /* __get_priority_stripe - get the next stripe to process 3805 * 3806 * Full stripe writes are allowed to pass preread active stripes up until 3807 * the bypass_threshold is exceeded. In general the bypass_count 3808 * increments when the handle_list is handled before the hold_list; however, it 3809 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a 3810 * stripe with in flight i/o. The bypass_count will be reset when the 3811 * head of the hold_list has changed, i.e. the head was promoted to the 3812 * handle_list. 3813 */ 3814 static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf) 3815 { 3816 struct stripe_head *sh; 3817 3818 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n", 3819 __func__, 3820 list_empty(&conf->handle_list) ? "empty" : "busy", 3821 list_empty(&conf->hold_list) ? "empty" : "busy", 3822 atomic_read(&conf->pending_full_writes), conf->bypass_count); 3823 3824 if (!list_empty(&conf->handle_list)) { 3825 sh = list_entry(conf->handle_list.next, typeof(*sh), lru); 3826 3827 if (list_empty(&conf->hold_list)) 3828 conf->bypass_count = 0; 3829 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) { 3830 if (conf->hold_list.next == conf->last_hold) 3831 conf->bypass_count++; 3832 else { 3833 conf->last_hold = conf->hold_list.next; 3834 conf->bypass_count -= conf->bypass_threshold; 3835 if (conf->bypass_count < 0) 3836 conf->bypass_count = 0; 3837 } 3838 } 3839 } else if (!list_empty(&conf->hold_list) && 3840 ((conf->bypass_threshold && 3841 conf->bypass_count > conf->bypass_threshold) || 3842 atomic_read(&conf->pending_full_writes) == 0)) { 3843 sh = list_entry(conf->hold_list.next, 3844 typeof(*sh), lru); 3845 conf->bypass_count -= conf->bypass_threshold; 3846 if (conf->bypass_count < 0) 3847 conf->bypass_count = 0; 3848 } else 3849 return NULL; 3850 3851 list_del_init(&sh->lru); 3852 atomic_inc(&sh->count); 3853 BUG_ON(atomic_read(&sh->count) != 1); 3854 return sh; 3855 } 3856 3857 static int make_request(struct request_queue *q, struct bio * bi) 3858 { 3859 mddev_t *mddev = q->queuedata; 3860 raid5_conf_t *conf = mddev->private; 3861 int dd_idx; 3862 sector_t new_sector; 3863 sector_t logical_sector, last_sector; 3864 struct stripe_head *sh; 3865 const int rw = bio_data_dir(bi); 3866 int cpu, remaining; 3867 3868 if (unlikely(bio_rw_flagged(bi, BIO_RW_BARRIER))) { 3869 bio_endio(bi, -EOPNOTSUPP); 3870 return 0; 3871 } 3872 3873 md_write_start(mddev, bi); 3874 3875 cpu = part_stat_lock(); 3876 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); 3877 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], 3878 bio_sectors(bi)); 3879 part_stat_unlock(); 3880 3881 if (rw == READ && 3882 mddev->reshape_position == MaxSector && 3883 chunk_aligned_read(q,bi)) 3884 return 0; 3885 3886 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 3887 last_sector = bi->bi_sector + (bi->bi_size>>9); 3888 bi->bi_next = NULL; 3889 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ 3890 3891 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { 3892 DEFINE_WAIT(w); 3893 int disks, data_disks; 3894 int previous; 3895 3896 retry: 3897 previous = 0; 3898 disks = conf->raid_disks; 3899 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); 3900 if (unlikely(conf->reshape_progress != MaxSector)) { 3901 /* spinlock is needed as reshape_progress may be 3902 * 64bit on a 32bit platform, and so it might be 3903 * possible to see a half-updated value 3904 * Ofcourse reshape_progress could change after 3905 * the lock is dropped, so once we get a reference 3906 * to the stripe that we think it is, we will have 3907 * to check again. 3908 */ 3909 spin_lock_irq(&conf->device_lock); 3910 if (mddev->delta_disks < 0 3911 ? logical_sector < conf->reshape_progress 3912 : logical_sector >= conf->reshape_progress) { 3913 disks = conf->previous_raid_disks; 3914 previous = 1; 3915 } else { 3916 if (mddev->delta_disks < 0 3917 ? logical_sector < conf->reshape_safe 3918 : logical_sector >= conf->reshape_safe) { 3919 spin_unlock_irq(&conf->device_lock); 3920 schedule(); 3921 goto retry; 3922 } 3923 } 3924 spin_unlock_irq(&conf->device_lock); 3925 } 3926 data_disks = disks - conf->max_degraded; 3927 3928 new_sector = raid5_compute_sector(conf, logical_sector, 3929 previous, 3930 &dd_idx, NULL); 3931 pr_debug("raid5: make_request, sector %llu logical %llu\n", 3932 (unsigned long long)new_sector, 3933 (unsigned long long)logical_sector); 3934 3935 sh = get_active_stripe(conf, new_sector, previous, 3936 (bi->bi_rw&RWA_MASK), 0); 3937 if (sh) { 3938 if (unlikely(previous)) { 3939 /* expansion might have moved on while waiting for a 3940 * stripe, so we must do the range check again. 3941 * Expansion could still move past after this 3942 * test, but as we are holding a reference to 3943 * 'sh', we know that if that happens, 3944 * STRIPE_EXPANDING will get set and the expansion 3945 * won't proceed until we finish with the stripe. 3946 */ 3947 int must_retry = 0; 3948 spin_lock_irq(&conf->device_lock); 3949 if (mddev->delta_disks < 0 3950 ? logical_sector >= conf->reshape_progress 3951 : logical_sector < conf->reshape_progress) 3952 /* mismatch, need to try again */ 3953 must_retry = 1; 3954 spin_unlock_irq(&conf->device_lock); 3955 if (must_retry) { 3956 release_stripe(sh); 3957 schedule(); 3958 goto retry; 3959 } 3960 } 3961 3962 if (bio_data_dir(bi) == WRITE && 3963 logical_sector >= mddev->suspend_lo && 3964 logical_sector < mddev->suspend_hi) { 3965 release_stripe(sh); 3966 /* As the suspend_* range is controlled by 3967 * userspace, we want an interruptible 3968 * wait. 3969 */ 3970 flush_signals(current); 3971 prepare_to_wait(&conf->wait_for_overlap, 3972 &w, TASK_INTERRUPTIBLE); 3973 if (logical_sector >= mddev->suspend_lo && 3974 logical_sector < mddev->suspend_hi) 3975 schedule(); 3976 goto retry; 3977 } 3978 3979 if (test_bit(STRIPE_EXPANDING, &sh->state) || 3980 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { 3981 /* Stripe is busy expanding or 3982 * add failed due to overlap. Flush everything 3983 * and wait a while 3984 */ 3985 raid5_unplug_device(mddev->queue); 3986 release_stripe(sh); 3987 schedule(); 3988 goto retry; 3989 } 3990 finish_wait(&conf->wait_for_overlap, &w); 3991 set_bit(STRIPE_HANDLE, &sh->state); 3992 clear_bit(STRIPE_DELAYED, &sh->state); 3993 release_stripe(sh); 3994 } else { 3995 /* cannot get stripe for read-ahead, just give-up */ 3996 clear_bit(BIO_UPTODATE, &bi->bi_flags); 3997 finish_wait(&conf->wait_for_overlap, &w); 3998 break; 3999 } 4000 4001 } 4002 spin_lock_irq(&conf->device_lock); 4003 remaining = raid5_dec_bi_phys_segments(bi); 4004 spin_unlock_irq(&conf->device_lock); 4005 if (remaining == 0) { 4006 4007 if ( rw == WRITE ) 4008 md_write_end(mddev); 4009 4010 bio_endio(bi, 0); 4011 } 4012 return 0; 4013 } 4014 4015 static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks); 4016 4017 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped) 4018 { 4019 /* reshaping is quite different to recovery/resync so it is 4020 * handled quite separately ... here. 4021 * 4022 * On each call to sync_request, we gather one chunk worth of 4023 * destination stripes and flag them as expanding. 4024 * Then we find all the source stripes and request reads. 4025 * As the reads complete, handle_stripe will copy the data 4026 * into the destination stripe and release that stripe. 4027 */ 4028 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 4029 struct stripe_head *sh; 4030 sector_t first_sector, last_sector; 4031 int raid_disks = conf->previous_raid_disks; 4032 int data_disks = raid_disks - conf->max_degraded; 4033 int new_data_disks = conf->raid_disks - conf->max_degraded; 4034 int i; 4035 int dd_idx; 4036 sector_t writepos, readpos, safepos; 4037 sector_t stripe_addr; 4038 int reshape_sectors; 4039 struct list_head stripes; 4040 4041 if (sector_nr == 0) { 4042 /* If restarting in the middle, skip the initial sectors */ 4043 if (mddev->delta_disks < 0 && 4044 conf->reshape_progress < raid5_size(mddev, 0, 0)) { 4045 sector_nr = raid5_size(mddev, 0, 0) 4046 - conf->reshape_progress; 4047 } else if (mddev->delta_disks >= 0 && 4048 conf->reshape_progress > 0) 4049 sector_nr = conf->reshape_progress; 4050 sector_div(sector_nr, new_data_disks); 4051 if (sector_nr) { 4052 mddev->curr_resync_completed = sector_nr; 4053 sysfs_notify(&mddev->kobj, NULL, "sync_completed"); 4054 *skipped = 1; 4055 return sector_nr; 4056 } 4057 } 4058 4059 /* We need to process a full chunk at a time. 4060 * If old and new chunk sizes differ, we need to process the 4061 * largest of these 4062 */ 4063 if (mddev->new_chunk_sectors > mddev->chunk_sectors) 4064 reshape_sectors = mddev->new_chunk_sectors; 4065 else 4066 reshape_sectors = mddev->chunk_sectors; 4067 4068 /* we update the metadata when there is more than 3Meg 4069 * in the block range (that is rather arbitrary, should 4070 * probably be time based) or when the data about to be 4071 * copied would over-write the source of the data at 4072 * the front of the range. 4073 * i.e. one new_stripe along from reshape_progress new_maps 4074 * to after where reshape_safe old_maps to 4075 */ 4076 writepos = conf->reshape_progress; 4077 sector_div(writepos, new_data_disks); 4078 readpos = conf->reshape_progress; 4079 sector_div(readpos, data_disks); 4080 safepos = conf->reshape_safe; 4081 sector_div(safepos, data_disks); 4082 if (mddev->delta_disks < 0) { 4083 writepos -= min_t(sector_t, reshape_sectors, writepos); 4084 readpos += reshape_sectors; 4085 safepos += reshape_sectors; 4086 } else { 4087 writepos += reshape_sectors; 4088 readpos -= min_t(sector_t, reshape_sectors, readpos); 4089 safepos -= min_t(sector_t, reshape_sectors, safepos); 4090 } 4091 4092 /* 'writepos' is the most advanced device address we might write. 4093 * 'readpos' is the least advanced device address we might read. 4094 * 'safepos' is the least address recorded in the metadata as having 4095 * been reshaped. 4096 * If 'readpos' is behind 'writepos', then there is no way that we can 4097 * ensure safety in the face of a crash - that must be done by userspace 4098 * making a backup of the data. So in that case there is no particular 4099 * rush to update metadata. 4100 * Otherwise if 'safepos' is behind 'writepos', then we really need to 4101 * update the metadata to advance 'safepos' to match 'readpos' so that 4102 * we can be safe in the event of a crash. 4103 * So we insist on updating metadata if safepos is behind writepos and 4104 * readpos is beyond writepos. 4105 * In any case, update the metadata every 10 seconds. 4106 * Maybe that number should be configurable, but I'm not sure it is 4107 * worth it.... maybe it could be a multiple of safemode_delay??? 4108 */ 4109 if ((mddev->delta_disks < 0 4110 ? (safepos > writepos && readpos < writepos) 4111 : (safepos < writepos && readpos > writepos)) || 4112 time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) { 4113 /* Cannot proceed until we've updated the superblock... */ 4114 wait_event(conf->wait_for_overlap, 4115 atomic_read(&conf->reshape_stripes)==0); 4116 mddev->reshape_position = conf->reshape_progress; 4117 mddev->curr_resync_completed = mddev->curr_resync; 4118 conf->reshape_checkpoint = jiffies; 4119 set_bit(MD_CHANGE_DEVS, &mddev->flags); 4120 md_wakeup_thread(mddev->thread); 4121 wait_event(mddev->sb_wait, mddev->flags == 0 || 4122 kthread_should_stop()); 4123 spin_lock_irq(&conf->device_lock); 4124 conf->reshape_safe = mddev->reshape_position; 4125 spin_unlock_irq(&conf->device_lock); 4126 wake_up(&conf->wait_for_overlap); 4127 sysfs_notify(&mddev->kobj, NULL, "sync_completed"); 4128 } 4129 4130 if (mddev->delta_disks < 0) { 4131 BUG_ON(conf->reshape_progress == 0); 4132 stripe_addr = writepos; 4133 BUG_ON((mddev->dev_sectors & 4134 ~((sector_t)reshape_sectors - 1)) 4135 - reshape_sectors - stripe_addr 4136 != sector_nr); 4137 } else { 4138 BUG_ON(writepos != sector_nr + reshape_sectors); 4139 stripe_addr = sector_nr; 4140 } 4141 INIT_LIST_HEAD(&stripes); 4142 for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) { 4143 int j; 4144 int skipped_disk = 0; 4145 sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1); 4146 set_bit(STRIPE_EXPANDING, &sh->state); 4147 atomic_inc(&conf->reshape_stripes); 4148 /* If any of this stripe is beyond the end of the old 4149 * array, then we need to zero those blocks 4150 */ 4151 for (j=sh->disks; j--;) { 4152 sector_t s; 4153 if (j == sh->pd_idx) 4154 continue; 4155 if (conf->level == 6 && 4156 j == sh->qd_idx) 4157 continue; 4158 s = compute_blocknr(sh, j, 0); 4159 if (s < raid5_size(mddev, 0, 0)) { 4160 skipped_disk = 1; 4161 continue; 4162 } 4163 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE); 4164 set_bit(R5_Expanded, &sh->dev[j].flags); 4165 set_bit(R5_UPTODATE, &sh->dev[j].flags); 4166 } 4167 if (!skipped_disk) { 4168 set_bit(STRIPE_EXPAND_READY, &sh->state); 4169 set_bit(STRIPE_HANDLE, &sh->state); 4170 } 4171 list_add(&sh->lru, &stripes); 4172 } 4173 spin_lock_irq(&conf->device_lock); 4174 if (mddev->delta_disks < 0) 4175 conf->reshape_progress -= reshape_sectors * new_data_disks; 4176 else 4177 conf->reshape_progress += reshape_sectors * new_data_disks; 4178 spin_unlock_irq(&conf->device_lock); 4179 /* Ok, those stripe are ready. We can start scheduling 4180 * reads on the source stripes. 4181 * The source stripes are determined by mapping the first and last 4182 * block on the destination stripes. 4183 */ 4184 first_sector = 4185 raid5_compute_sector(conf, stripe_addr*(new_data_disks), 4186 1, &dd_idx, NULL); 4187 last_sector = 4188 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors) 4189 * new_data_disks - 1), 4190 1, &dd_idx, NULL); 4191 if (last_sector >= mddev->dev_sectors) 4192 last_sector = mddev->dev_sectors - 1; 4193 while (first_sector <= last_sector) { 4194 sh = get_active_stripe(conf, first_sector, 1, 0, 1); 4195 set_bit(STRIPE_EXPAND_SOURCE, &sh->state); 4196 set_bit(STRIPE_HANDLE, &sh->state); 4197 release_stripe(sh); 4198 first_sector += STRIPE_SECTORS; 4199 } 4200 /* Now that the sources are clearly marked, we can release 4201 * the destination stripes 4202 */ 4203 while (!list_empty(&stripes)) { 4204 sh = list_entry(stripes.next, struct stripe_head, lru); 4205 list_del_init(&sh->lru); 4206 release_stripe(sh); 4207 } 4208 /* If this takes us to the resync_max point where we have to pause, 4209 * then we need to write out the superblock. 4210 */ 4211 sector_nr += reshape_sectors; 4212 if ((sector_nr - mddev->curr_resync_completed) * 2 4213 >= mddev->resync_max - mddev->curr_resync_completed) { 4214 /* Cannot proceed until we've updated the superblock... */ 4215 wait_event(conf->wait_for_overlap, 4216 atomic_read(&conf->reshape_stripes) == 0); 4217 mddev->reshape_position = conf->reshape_progress; 4218 mddev->curr_resync_completed = mddev->curr_resync + reshape_sectors; 4219 conf->reshape_checkpoint = jiffies; 4220 set_bit(MD_CHANGE_DEVS, &mddev->flags); 4221 md_wakeup_thread(mddev->thread); 4222 wait_event(mddev->sb_wait, 4223 !test_bit(MD_CHANGE_DEVS, &mddev->flags) 4224 || kthread_should_stop()); 4225 spin_lock_irq(&conf->device_lock); 4226 conf->reshape_safe = mddev->reshape_position; 4227 spin_unlock_irq(&conf->device_lock); 4228 wake_up(&conf->wait_for_overlap); 4229 sysfs_notify(&mddev->kobj, NULL, "sync_completed"); 4230 } 4231 return reshape_sectors; 4232 } 4233 4234 /* FIXME go_faster isn't used */ 4235 static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 4236 { 4237 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 4238 struct stripe_head *sh; 4239 sector_t max_sector = mddev->dev_sectors; 4240 int sync_blocks; 4241 int still_degraded = 0; 4242 int i; 4243 4244 if (sector_nr >= max_sector) { 4245 /* just being told to finish up .. nothing much to do */ 4246 unplug_slaves(mddev); 4247 4248 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) { 4249 end_reshape(conf); 4250 return 0; 4251 } 4252 4253 if (mddev->curr_resync < max_sector) /* aborted */ 4254 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 4255 &sync_blocks, 1); 4256 else /* completed sync */ 4257 conf->fullsync = 0; 4258 bitmap_close_sync(mddev->bitmap); 4259 4260 return 0; 4261 } 4262 4263 /* Allow raid5_quiesce to complete */ 4264 wait_event(conf->wait_for_overlap, conf->quiesce != 2); 4265 4266 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) 4267 return reshape_request(mddev, sector_nr, skipped); 4268 4269 /* No need to check resync_max as we never do more than one 4270 * stripe, and as resync_max will always be on a chunk boundary, 4271 * if the check in md_do_sync didn't fire, there is no chance 4272 * of overstepping resync_max here 4273 */ 4274 4275 /* if there is too many failed drives and we are trying 4276 * to resync, then assert that we are finished, because there is 4277 * nothing we can do. 4278 */ 4279 if (mddev->degraded >= conf->max_degraded && 4280 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 4281 sector_t rv = mddev->dev_sectors - sector_nr; 4282 *skipped = 1; 4283 return rv; 4284 } 4285 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && 4286 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && 4287 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { 4288 /* we can skip this block, and probably more */ 4289 sync_blocks /= STRIPE_SECTORS; 4290 *skipped = 1; 4291 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ 4292 } 4293 4294 4295 bitmap_cond_end_sync(mddev->bitmap, sector_nr); 4296 4297 sh = get_active_stripe(conf, sector_nr, 0, 1, 0); 4298 if (sh == NULL) { 4299 sh = get_active_stripe(conf, sector_nr, 0, 0, 0); 4300 /* make sure we don't swamp the stripe cache if someone else 4301 * is trying to get access 4302 */ 4303 schedule_timeout_uninterruptible(1); 4304 } 4305 /* Need to check if array will still be degraded after recovery/resync 4306 * We don't need to check the 'failed' flag as when that gets set, 4307 * recovery aborts. 4308 */ 4309 for (i = 0; i < conf->raid_disks; i++) 4310 if (conf->disks[i].rdev == NULL) 4311 still_degraded = 1; 4312 4313 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded); 4314 4315 spin_lock(&sh->lock); 4316 set_bit(STRIPE_SYNCING, &sh->state); 4317 clear_bit(STRIPE_INSYNC, &sh->state); 4318 spin_unlock(&sh->lock); 4319 4320 handle_stripe(sh); 4321 release_stripe(sh); 4322 4323 return STRIPE_SECTORS; 4324 } 4325 4326 static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) 4327 { 4328 /* We may not be able to submit a whole bio at once as there 4329 * may not be enough stripe_heads available. 4330 * We cannot pre-allocate enough stripe_heads as we may need 4331 * more than exist in the cache (if we allow ever large chunks). 4332 * So we do one stripe head at a time and record in 4333 * ->bi_hw_segments how many have been done. 4334 * 4335 * We *know* that this entire raid_bio is in one chunk, so 4336 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector. 4337 */ 4338 struct stripe_head *sh; 4339 int dd_idx; 4340 sector_t sector, logical_sector, last_sector; 4341 int scnt = 0; 4342 int remaining; 4343 int handled = 0; 4344 4345 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 4346 sector = raid5_compute_sector(conf, logical_sector, 4347 0, &dd_idx, NULL); 4348 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9); 4349 4350 for (; logical_sector < last_sector; 4351 logical_sector += STRIPE_SECTORS, 4352 sector += STRIPE_SECTORS, 4353 scnt++) { 4354 4355 if (scnt < raid5_bi_hw_segments(raid_bio)) 4356 /* already done this stripe */ 4357 continue; 4358 4359 sh = get_active_stripe(conf, sector, 0, 1, 0); 4360 4361 if (!sh) { 4362 /* failed to get a stripe - must wait */ 4363 raid5_set_bi_hw_segments(raid_bio, scnt); 4364 conf->retry_read_aligned = raid_bio; 4365 return handled; 4366 } 4367 4368 set_bit(R5_ReadError, &sh->dev[dd_idx].flags); 4369 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) { 4370 release_stripe(sh); 4371 raid5_set_bi_hw_segments(raid_bio, scnt); 4372 conf->retry_read_aligned = raid_bio; 4373 return handled; 4374 } 4375 4376 handle_stripe(sh); 4377 release_stripe(sh); 4378 handled++; 4379 } 4380 spin_lock_irq(&conf->device_lock); 4381 remaining = raid5_dec_bi_phys_segments(raid_bio); 4382 spin_unlock_irq(&conf->device_lock); 4383 if (remaining == 0) 4384 bio_endio(raid_bio, 0); 4385 if (atomic_dec_and_test(&conf->active_aligned_reads)) 4386 wake_up(&conf->wait_for_stripe); 4387 return handled; 4388 } 4389 4390 4391 /* 4392 * This is our raid5 kernel thread. 4393 * 4394 * We scan the hash table for stripes which can be handled now. 4395 * During the scan, completed stripes are saved for us by the interrupt 4396 * handler, so that they will not have to wait for our next wakeup. 4397 */ 4398 static void raid5d(mddev_t *mddev) 4399 { 4400 struct stripe_head *sh; 4401 raid5_conf_t *conf = mddev->private; 4402 int handled; 4403 4404 pr_debug("+++ raid5d active\n"); 4405 4406 md_check_recovery(mddev); 4407 4408 handled = 0; 4409 spin_lock_irq(&conf->device_lock); 4410 while (1) { 4411 struct bio *bio; 4412 4413 if (conf->seq_flush != conf->seq_write) { 4414 int seq = conf->seq_flush; 4415 spin_unlock_irq(&conf->device_lock); 4416 bitmap_unplug(mddev->bitmap); 4417 spin_lock_irq(&conf->device_lock); 4418 conf->seq_write = seq; 4419 activate_bit_delay(conf); 4420 } 4421 4422 while ((bio = remove_bio_from_retry(conf))) { 4423 int ok; 4424 spin_unlock_irq(&conf->device_lock); 4425 ok = retry_aligned_read(conf, bio); 4426 spin_lock_irq(&conf->device_lock); 4427 if (!ok) 4428 break; 4429 handled++; 4430 } 4431 4432 sh = __get_priority_stripe(conf); 4433 4434 if (!sh) 4435 break; 4436 spin_unlock_irq(&conf->device_lock); 4437 4438 handled++; 4439 handle_stripe(sh); 4440 release_stripe(sh); 4441 cond_resched(); 4442 4443 spin_lock_irq(&conf->device_lock); 4444 } 4445 pr_debug("%d stripes handled\n", handled); 4446 4447 spin_unlock_irq(&conf->device_lock); 4448 4449 async_tx_issue_pending_all(); 4450 unplug_slaves(mddev); 4451 4452 pr_debug("--- raid5d inactive\n"); 4453 } 4454 4455 static ssize_t 4456 raid5_show_stripe_cache_size(mddev_t *mddev, char *page) 4457 { 4458 raid5_conf_t *conf = mddev->private; 4459 if (conf) 4460 return sprintf(page, "%d\n", conf->max_nr_stripes); 4461 else 4462 return 0; 4463 } 4464 4465 static ssize_t 4466 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 4467 { 4468 raid5_conf_t *conf = mddev->private; 4469 unsigned long new; 4470 int err; 4471 4472 if (len >= PAGE_SIZE) 4473 return -EINVAL; 4474 if (!conf) 4475 return -ENODEV; 4476 4477 if (strict_strtoul(page, 10, &new)) 4478 return -EINVAL; 4479 if (new <= 16 || new > 32768) 4480 return -EINVAL; 4481 while (new < conf->max_nr_stripes) { 4482 if (drop_one_stripe(conf)) 4483 conf->max_nr_stripes--; 4484 else 4485 break; 4486 } 4487 err = md_allow_write(mddev); 4488 if (err) 4489 return err; 4490 while (new > conf->max_nr_stripes) { 4491 if (grow_one_stripe(conf)) 4492 conf->max_nr_stripes++; 4493 else break; 4494 } 4495 return len; 4496 } 4497 4498 static struct md_sysfs_entry 4499 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, 4500 raid5_show_stripe_cache_size, 4501 raid5_store_stripe_cache_size); 4502 4503 static ssize_t 4504 raid5_show_preread_threshold(mddev_t *mddev, char *page) 4505 { 4506 raid5_conf_t *conf = mddev->private; 4507 if (conf) 4508 return sprintf(page, "%d\n", conf->bypass_threshold); 4509 else 4510 return 0; 4511 } 4512 4513 static ssize_t 4514 raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len) 4515 { 4516 raid5_conf_t *conf = mddev->private; 4517 unsigned long new; 4518 if (len >= PAGE_SIZE) 4519 return -EINVAL; 4520 if (!conf) 4521 return -ENODEV; 4522 4523 if (strict_strtoul(page, 10, &new)) 4524 return -EINVAL; 4525 if (new > conf->max_nr_stripes) 4526 return -EINVAL; 4527 conf->bypass_threshold = new; 4528 return len; 4529 } 4530 4531 static struct md_sysfs_entry 4532 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold, 4533 S_IRUGO | S_IWUSR, 4534 raid5_show_preread_threshold, 4535 raid5_store_preread_threshold); 4536 4537 static ssize_t 4538 stripe_cache_active_show(mddev_t *mddev, char *page) 4539 { 4540 raid5_conf_t *conf = mddev->private; 4541 if (conf) 4542 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes)); 4543 else 4544 return 0; 4545 } 4546 4547 static struct md_sysfs_entry 4548 raid5_stripecache_active = __ATTR_RO(stripe_cache_active); 4549 4550 static struct attribute *raid5_attrs[] = { 4551 &raid5_stripecache_size.attr, 4552 &raid5_stripecache_active.attr, 4553 &raid5_preread_bypass_threshold.attr, 4554 NULL, 4555 }; 4556 static struct attribute_group raid5_attrs_group = { 4557 .name = NULL, 4558 .attrs = raid5_attrs, 4559 }; 4560 4561 static sector_t 4562 raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks) 4563 { 4564 raid5_conf_t *conf = mddev->private; 4565 4566 if (!sectors) 4567 sectors = mddev->dev_sectors; 4568 if (!raid_disks) 4569 /* size is defined by the smallest of previous and new size */ 4570 raid_disks = min(conf->raid_disks, conf->previous_raid_disks); 4571 4572 sectors &= ~((sector_t)mddev->chunk_sectors - 1); 4573 sectors &= ~((sector_t)mddev->new_chunk_sectors - 1); 4574 return sectors * (raid_disks - conf->max_degraded); 4575 } 4576 4577 static void raid5_free_percpu(raid5_conf_t *conf) 4578 { 4579 struct raid5_percpu *percpu; 4580 unsigned long cpu; 4581 4582 if (!conf->percpu) 4583 return; 4584 4585 get_online_cpus(); 4586 for_each_possible_cpu(cpu) { 4587 percpu = per_cpu_ptr(conf->percpu, cpu); 4588 safe_put_page(percpu->spare_page); 4589 kfree(percpu->scribble); 4590 } 4591 #ifdef CONFIG_HOTPLUG_CPU 4592 unregister_cpu_notifier(&conf->cpu_notify); 4593 #endif 4594 put_online_cpus(); 4595 4596 free_percpu(conf->percpu); 4597 } 4598 4599 static void free_conf(raid5_conf_t *conf) 4600 { 4601 shrink_stripes(conf); 4602 raid5_free_percpu(conf); 4603 kfree(conf->disks); 4604 kfree(conf->stripe_hashtbl); 4605 kfree(conf); 4606 } 4607 4608 #ifdef CONFIG_HOTPLUG_CPU 4609 static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action, 4610 void *hcpu) 4611 { 4612 raid5_conf_t *conf = container_of(nfb, raid5_conf_t, cpu_notify); 4613 long cpu = (long)hcpu; 4614 struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu); 4615 4616 switch (action) { 4617 case CPU_UP_PREPARE: 4618 case CPU_UP_PREPARE_FROZEN: 4619 if (conf->level == 6 && !percpu->spare_page) 4620 percpu->spare_page = alloc_page(GFP_KERNEL); 4621 if (!percpu->scribble) 4622 percpu->scribble = kmalloc(conf->scribble_len, GFP_KERNEL); 4623 4624 if (!percpu->scribble || 4625 (conf->level == 6 && !percpu->spare_page)) { 4626 safe_put_page(percpu->spare_page); 4627 kfree(percpu->scribble); 4628 pr_err("%s: failed memory allocation for cpu%ld\n", 4629 __func__, cpu); 4630 return NOTIFY_BAD; 4631 } 4632 break; 4633 case CPU_DEAD: 4634 case CPU_DEAD_FROZEN: 4635 safe_put_page(percpu->spare_page); 4636 kfree(percpu->scribble); 4637 percpu->spare_page = NULL; 4638 percpu->scribble = NULL; 4639 break; 4640 default: 4641 break; 4642 } 4643 return NOTIFY_OK; 4644 } 4645 #endif 4646 4647 static int raid5_alloc_percpu(raid5_conf_t *conf) 4648 { 4649 unsigned long cpu; 4650 struct page *spare_page; 4651 struct raid5_percpu *allcpus; 4652 void *scribble; 4653 int err; 4654 4655 allcpus = alloc_percpu(struct raid5_percpu); 4656 if (!allcpus) 4657 return -ENOMEM; 4658 conf->percpu = allcpus; 4659 4660 get_online_cpus(); 4661 err = 0; 4662 for_each_present_cpu(cpu) { 4663 if (conf->level == 6) { 4664 spare_page = alloc_page(GFP_KERNEL); 4665 if (!spare_page) { 4666 err = -ENOMEM; 4667 break; 4668 } 4669 per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page; 4670 } 4671 scribble = kmalloc(conf->scribble_len, GFP_KERNEL); 4672 if (!scribble) { 4673 err = -ENOMEM; 4674 break; 4675 } 4676 per_cpu_ptr(conf->percpu, cpu)->scribble = scribble; 4677 } 4678 #ifdef CONFIG_HOTPLUG_CPU 4679 conf->cpu_notify.notifier_call = raid456_cpu_notify; 4680 conf->cpu_notify.priority = 0; 4681 if (err == 0) 4682 err = register_cpu_notifier(&conf->cpu_notify); 4683 #endif 4684 put_online_cpus(); 4685 4686 return err; 4687 } 4688 4689 static raid5_conf_t *setup_conf(mddev_t *mddev) 4690 { 4691 raid5_conf_t *conf; 4692 int raid_disk, memory, max_disks; 4693 mdk_rdev_t *rdev; 4694 struct disk_info *disk; 4695 4696 if (mddev->new_level != 5 4697 && mddev->new_level != 4 4698 && mddev->new_level != 6) { 4699 printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n", 4700 mdname(mddev), mddev->new_level); 4701 return ERR_PTR(-EIO); 4702 } 4703 if ((mddev->new_level == 5 4704 && !algorithm_valid_raid5(mddev->new_layout)) || 4705 (mddev->new_level == 6 4706 && !algorithm_valid_raid6(mddev->new_layout))) { 4707 printk(KERN_ERR "raid5: %s: layout %d not supported\n", 4708 mdname(mddev), mddev->new_layout); 4709 return ERR_PTR(-EIO); 4710 } 4711 if (mddev->new_level == 6 && mddev->raid_disks < 4) { 4712 printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n", 4713 mdname(mddev), mddev->raid_disks); 4714 return ERR_PTR(-EINVAL); 4715 } 4716 4717 if (!mddev->new_chunk_sectors || 4718 (mddev->new_chunk_sectors << 9) % PAGE_SIZE || 4719 !is_power_of_2(mddev->new_chunk_sectors)) { 4720 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", 4721 mddev->new_chunk_sectors << 9, mdname(mddev)); 4722 return ERR_PTR(-EINVAL); 4723 } 4724 4725 conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL); 4726 if (conf == NULL) 4727 goto abort; 4728 spin_lock_init(&conf->device_lock); 4729 init_waitqueue_head(&conf->wait_for_stripe); 4730 init_waitqueue_head(&conf->wait_for_overlap); 4731 INIT_LIST_HEAD(&conf->handle_list); 4732 INIT_LIST_HEAD(&conf->hold_list); 4733 INIT_LIST_HEAD(&conf->delayed_list); 4734 INIT_LIST_HEAD(&conf->bitmap_list); 4735 INIT_LIST_HEAD(&conf->inactive_list); 4736 atomic_set(&conf->active_stripes, 0); 4737 atomic_set(&conf->preread_active_stripes, 0); 4738 atomic_set(&conf->active_aligned_reads, 0); 4739 conf->bypass_threshold = BYPASS_THRESHOLD; 4740 4741 conf->raid_disks = mddev->raid_disks; 4742 if (mddev->reshape_position == MaxSector) 4743 conf->previous_raid_disks = mddev->raid_disks; 4744 else 4745 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks; 4746 max_disks = max(conf->raid_disks, conf->previous_raid_disks); 4747 conf->scribble_len = scribble_len(max_disks); 4748 4749 conf->disks = kzalloc(max_disks * sizeof(struct disk_info), 4750 GFP_KERNEL); 4751 if (!conf->disks) 4752 goto abort; 4753 4754 conf->mddev = mddev; 4755 4756 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) 4757 goto abort; 4758 4759 conf->level = mddev->new_level; 4760 if (raid5_alloc_percpu(conf) != 0) 4761 goto abort; 4762 4763 pr_debug("raid5: run(%s) called.\n", mdname(mddev)); 4764 4765 list_for_each_entry(rdev, &mddev->disks, same_set) { 4766 raid_disk = rdev->raid_disk; 4767 if (raid_disk >= max_disks 4768 || raid_disk < 0) 4769 continue; 4770 disk = conf->disks + raid_disk; 4771 4772 disk->rdev = rdev; 4773 4774 if (test_bit(In_sync, &rdev->flags)) { 4775 char b[BDEVNAME_SIZE]; 4776 printk(KERN_INFO "raid5: device %s operational as raid" 4777 " disk %d\n", bdevname(rdev->bdev,b), 4778 raid_disk); 4779 } else 4780 /* Cannot rely on bitmap to complete recovery */ 4781 conf->fullsync = 1; 4782 } 4783 4784 conf->chunk_sectors = mddev->new_chunk_sectors; 4785 conf->level = mddev->new_level; 4786 if (conf->level == 6) 4787 conf->max_degraded = 2; 4788 else 4789 conf->max_degraded = 1; 4790 conf->algorithm = mddev->new_layout; 4791 conf->max_nr_stripes = NR_STRIPES; 4792 conf->reshape_progress = mddev->reshape_position; 4793 if (conf->reshape_progress != MaxSector) { 4794 conf->prev_chunk_sectors = mddev->chunk_sectors; 4795 conf->prev_algo = mddev->layout; 4796 } 4797 4798 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + 4799 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; 4800 if (grow_stripes(conf, conf->max_nr_stripes)) { 4801 printk(KERN_ERR 4802 "raid5: couldn't allocate %dkB for buffers\n", memory); 4803 goto abort; 4804 } else 4805 printk(KERN_INFO "raid5: allocated %dkB for %s\n", 4806 memory, mdname(mddev)); 4807 4808 conf->thread = md_register_thread(raid5d, mddev, NULL); 4809 if (!conf->thread) { 4810 printk(KERN_ERR 4811 "raid5: couldn't allocate thread for %s\n", 4812 mdname(mddev)); 4813 goto abort; 4814 } 4815 4816 return conf; 4817 4818 abort: 4819 if (conf) { 4820 free_conf(conf); 4821 return ERR_PTR(-EIO); 4822 } else 4823 return ERR_PTR(-ENOMEM); 4824 } 4825 4826 4827 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded) 4828 { 4829 switch (algo) { 4830 case ALGORITHM_PARITY_0: 4831 if (raid_disk < max_degraded) 4832 return 1; 4833 break; 4834 case ALGORITHM_PARITY_N: 4835 if (raid_disk >= raid_disks - max_degraded) 4836 return 1; 4837 break; 4838 case ALGORITHM_PARITY_0_6: 4839 if (raid_disk == 0 || 4840 raid_disk == raid_disks - 1) 4841 return 1; 4842 break; 4843 case ALGORITHM_LEFT_ASYMMETRIC_6: 4844 case ALGORITHM_RIGHT_ASYMMETRIC_6: 4845 case ALGORITHM_LEFT_SYMMETRIC_6: 4846 case ALGORITHM_RIGHT_SYMMETRIC_6: 4847 if (raid_disk == raid_disks - 1) 4848 return 1; 4849 } 4850 return 0; 4851 } 4852 4853 static int run(mddev_t *mddev) 4854 { 4855 raid5_conf_t *conf; 4856 int working_disks = 0, chunk_size; 4857 int dirty_parity_disks = 0; 4858 mdk_rdev_t *rdev; 4859 sector_t reshape_offset = 0; 4860 4861 if (mddev->recovery_cp != MaxSector) 4862 printk(KERN_NOTICE "raid5: %s is not clean" 4863 " -- starting background reconstruction\n", 4864 mdname(mddev)); 4865 if (mddev->reshape_position != MaxSector) { 4866 /* Check that we can continue the reshape. 4867 * Currently only disks can change, it must 4868 * increase, and we must be past the point where 4869 * a stripe over-writes itself 4870 */ 4871 sector_t here_new, here_old; 4872 int old_disks; 4873 int max_degraded = (mddev->level == 6 ? 2 : 1); 4874 4875 if (mddev->new_level != mddev->level) { 4876 printk(KERN_ERR "raid5: %s: unsupported reshape " 4877 "required - aborting.\n", 4878 mdname(mddev)); 4879 return -EINVAL; 4880 } 4881 old_disks = mddev->raid_disks - mddev->delta_disks; 4882 /* reshape_position must be on a new-stripe boundary, and one 4883 * further up in new geometry must map after here in old 4884 * geometry. 4885 */ 4886 here_new = mddev->reshape_position; 4887 if (sector_div(here_new, mddev->new_chunk_sectors * 4888 (mddev->raid_disks - max_degraded))) { 4889 printk(KERN_ERR "raid5: reshape_position not " 4890 "on a stripe boundary\n"); 4891 return -EINVAL; 4892 } 4893 reshape_offset = here_new * mddev->new_chunk_sectors; 4894 /* here_new is the stripe we will write to */ 4895 here_old = mddev->reshape_position; 4896 sector_div(here_old, mddev->chunk_sectors * 4897 (old_disks-max_degraded)); 4898 /* here_old is the first stripe that we might need to read 4899 * from */ 4900 if (mddev->delta_disks == 0) { 4901 /* We cannot be sure it is safe to start an in-place 4902 * reshape. It is only safe if user-space if monitoring 4903 * and taking constant backups. 4904 * mdadm always starts a situation like this in 4905 * readonly mode so it can take control before 4906 * allowing any writes. So just check for that. 4907 */ 4908 if ((here_new * mddev->new_chunk_sectors != 4909 here_old * mddev->chunk_sectors) || 4910 mddev->ro == 0) { 4911 printk(KERN_ERR "raid5: in-place reshape must be started" 4912 " in read-only mode - aborting\n"); 4913 return -EINVAL; 4914 } 4915 } else if (mddev->delta_disks < 0 4916 ? (here_new * mddev->new_chunk_sectors <= 4917 here_old * mddev->chunk_sectors) 4918 : (here_new * mddev->new_chunk_sectors >= 4919 here_old * mddev->chunk_sectors)) { 4920 /* Reading from the same stripe as writing to - bad */ 4921 printk(KERN_ERR "raid5: reshape_position too early for " 4922 "auto-recovery - aborting.\n"); 4923 return -EINVAL; 4924 } 4925 printk(KERN_INFO "raid5: reshape will continue\n"); 4926 /* OK, we should be able to continue; */ 4927 } else { 4928 BUG_ON(mddev->level != mddev->new_level); 4929 BUG_ON(mddev->layout != mddev->new_layout); 4930 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors); 4931 BUG_ON(mddev->delta_disks != 0); 4932 } 4933 4934 if (mddev->private == NULL) 4935 conf = setup_conf(mddev); 4936 else 4937 conf = mddev->private; 4938 4939 if (IS_ERR(conf)) 4940 return PTR_ERR(conf); 4941 4942 mddev->thread = conf->thread; 4943 conf->thread = NULL; 4944 mddev->private = conf; 4945 4946 /* 4947 * 0 for a fully functional array, 1 or 2 for a degraded array. 4948 */ 4949 list_for_each_entry(rdev, &mddev->disks, same_set) { 4950 if (rdev->raid_disk < 0) 4951 continue; 4952 if (test_bit(In_sync, &rdev->flags)) 4953 working_disks++; 4954 /* This disc is not fully in-sync. However if it 4955 * just stored parity (beyond the recovery_offset), 4956 * when we don't need to be concerned about the 4957 * array being dirty. 4958 * When reshape goes 'backwards', we never have 4959 * partially completed devices, so we only need 4960 * to worry about reshape going forwards. 4961 */ 4962 /* Hack because v0.91 doesn't store recovery_offset properly. */ 4963 if (mddev->major_version == 0 && 4964 mddev->minor_version > 90) 4965 rdev->recovery_offset = reshape_offset; 4966 4967 printk("%d: w=%d pa=%d pr=%d m=%d a=%d r=%d op1=%d op2=%d\n", 4968 rdev->raid_disk, working_disks, conf->prev_algo, 4969 conf->previous_raid_disks, conf->max_degraded, 4970 conf->algorithm, conf->raid_disks, 4971 only_parity(rdev->raid_disk, 4972 conf->prev_algo, 4973 conf->previous_raid_disks, 4974 conf->max_degraded), 4975 only_parity(rdev->raid_disk, 4976 conf->algorithm, 4977 conf->raid_disks, 4978 conf->max_degraded)); 4979 if (rdev->recovery_offset < reshape_offset) { 4980 /* We need to check old and new layout */ 4981 if (!only_parity(rdev->raid_disk, 4982 conf->algorithm, 4983 conf->raid_disks, 4984 conf->max_degraded)) 4985 continue; 4986 } 4987 if (!only_parity(rdev->raid_disk, 4988 conf->prev_algo, 4989 conf->previous_raid_disks, 4990 conf->max_degraded)) 4991 continue; 4992 dirty_parity_disks++; 4993 } 4994 4995 mddev->degraded = (max(conf->raid_disks, conf->previous_raid_disks) 4996 - working_disks); 4997 4998 if (mddev->degraded > conf->max_degraded) { 4999 printk(KERN_ERR "raid5: not enough operational devices for %s" 5000 " (%d/%d failed)\n", 5001 mdname(mddev), mddev->degraded, conf->raid_disks); 5002 goto abort; 5003 } 5004 5005 /* device size must be a multiple of chunk size */ 5006 mddev->dev_sectors &= ~(mddev->chunk_sectors - 1); 5007 mddev->resync_max_sectors = mddev->dev_sectors; 5008 5009 if (mddev->degraded > dirty_parity_disks && 5010 mddev->recovery_cp != MaxSector) { 5011 if (mddev->ok_start_degraded) 5012 printk(KERN_WARNING 5013 "raid5: starting dirty degraded array: %s" 5014 "- data corruption possible.\n", 5015 mdname(mddev)); 5016 else { 5017 printk(KERN_ERR 5018 "raid5: cannot start dirty degraded array for %s\n", 5019 mdname(mddev)); 5020 goto abort; 5021 } 5022 } 5023 5024 if (mddev->degraded == 0) 5025 printk("raid5: raid level %d set %s active with %d out of %d" 5026 " devices, algorithm %d\n", conf->level, mdname(mddev), 5027 mddev->raid_disks-mddev->degraded, mddev->raid_disks, 5028 mddev->new_layout); 5029 else 5030 printk(KERN_ALERT "raid5: raid level %d set %s active with %d" 5031 " out of %d devices, algorithm %d\n", conf->level, 5032 mdname(mddev), mddev->raid_disks - mddev->degraded, 5033 mddev->raid_disks, mddev->new_layout); 5034 5035 print_raid5_conf(conf); 5036 5037 if (conf->reshape_progress != MaxSector) { 5038 printk("...ok start reshape thread\n"); 5039 conf->reshape_safe = conf->reshape_progress; 5040 atomic_set(&conf->reshape_stripes, 0); 5041 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 5042 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 5043 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 5044 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 5045 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 5046 "reshape"); 5047 } 5048 5049 /* read-ahead size must cover two whole stripes, which is 5050 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 5051 */ 5052 { 5053 int data_disks = conf->previous_raid_disks - conf->max_degraded; 5054 int stripe = data_disks * 5055 ((mddev->chunk_sectors << 9) / PAGE_SIZE); 5056 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 5057 mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 5058 } 5059 5060 /* Ok, everything is just fine now */ 5061 if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group)) 5062 printk(KERN_WARNING 5063 "raid5: failed to create sysfs attributes for %s\n", 5064 mdname(mddev)); 5065 5066 mddev->queue->queue_lock = &conf->device_lock; 5067 5068 mddev->queue->unplug_fn = raid5_unplug_device; 5069 mddev->queue->backing_dev_info.congested_data = mddev; 5070 mddev->queue->backing_dev_info.congested_fn = raid5_congested; 5071 5072 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0)); 5073 5074 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); 5075 chunk_size = mddev->chunk_sectors << 9; 5076 blk_queue_io_min(mddev->queue, chunk_size); 5077 blk_queue_io_opt(mddev->queue, chunk_size * 5078 (conf->raid_disks - conf->max_degraded)); 5079 5080 list_for_each_entry(rdev, &mddev->disks, same_set) 5081 disk_stack_limits(mddev->gendisk, rdev->bdev, 5082 rdev->data_offset << 9); 5083 5084 return 0; 5085 abort: 5086 md_unregister_thread(mddev->thread); 5087 mddev->thread = NULL; 5088 if (conf) { 5089 print_raid5_conf(conf); 5090 free_conf(conf); 5091 } 5092 mddev->private = NULL; 5093 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); 5094 return -EIO; 5095 } 5096 5097 5098 5099 static int stop(mddev_t *mddev) 5100 { 5101 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 5102 5103 md_unregister_thread(mddev->thread); 5104 mddev->thread = NULL; 5105 mddev->queue->backing_dev_info.congested_fn = NULL; 5106 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 5107 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group); 5108 free_conf(conf); 5109 mddev->private = NULL; 5110 return 0; 5111 } 5112 5113 #ifdef DEBUG 5114 static void print_sh(struct seq_file *seq, struct stripe_head *sh) 5115 { 5116 int i; 5117 5118 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n", 5119 (unsigned long long)sh->sector, sh->pd_idx, sh->state); 5120 seq_printf(seq, "sh %llu, count %d.\n", 5121 (unsigned long long)sh->sector, atomic_read(&sh->count)); 5122 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector); 5123 for (i = 0; i < sh->disks; i++) { 5124 seq_printf(seq, "(cache%d: %p %ld) ", 5125 i, sh->dev[i].page, sh->dev[i].flags); 5126 } 5127 seq_printf(seq, "\n"); 5128 } 5129 5130 static void printall(struct seq_file *seq, raid5_conf_t *conf) 5131 { 5132 struct stripe_head *sh; 5133 struct hlist_node *hn; 5134 int i; 5135 5136 spin_lock_irq(&conf->device_lock); 5137 for (i = 0; i < NR_HASH; i++) { 5138 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) { 5139 if (sh->raid_conf != conf) 5140 continue; 5141 print_sh(seq, sh); 5142 } 5143 } 5144 spin_unlock_irq(&conf->device_lock); 5145 } 5146 #endif 5147 5148 static void status(struct seq_file *seq, mddev_t *mddev) 5149 { 5150 raid5_conf_t *conf = (raid5_conf_t *) mddev->private; 5151 int i; 5152 5153 seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level, 5154 mddev->chunk_sectors / 2, mddev->layout); 5155 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); 5156 for (i = 0; i < conf->raid_disks; i++) 5157 seq_printf (seq, "%s", 5158 conf->disks[i].rdev && 5159 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_"); 5160 seq_printf (seq, "]"); 5161 #ifdef DEBUG 5162 seq_printf (seq, "\n"); 5163 printall(seq, conf); 5164 #endif 5165 } 5166 5167 static void print_raid5_conf (raid5_conf_t *conf) 5168 { 5169 int i; 5170 struct disk_info *tmp; 5171 5172 printk("RAID5 conf printout:\n"); 5173 if (!conf) { 5174 printk("(conf==NULL)\n"); 5175 return; 5176 } 5177 printk(" --- rd:%d wd:%d\n", conf->raid_disks, 5178 conf->raid_disks - conf->mddev->degraded); 5179 5180 for (i = 0; i < conf->raid_disks; i++) { 5181 char b[BDEVNAME_SIZE]; 5182 tmp = conf->disks + i; 5183 if (tmp->rdev) 5184 printk(" disk %d, o:%d, dev:%s\n", 5185 i, !test_bit(Faulty, &tmp->rdev->flags), 5186 bdevname(tmp->rdev->bdev,b)); 5187 } 5188 } 5189 5190 static int raid5_spare_active(mddev_t *mddev) 5191 { 5192 int i; 5193 raid5_conf_t *conf = mddev->private; 5194 struct disk_info *tmp; 5195 5196 for (i = 0; i < conf->raid_disks; i++) { 5197 tmp = conf->disks + i; 5198 if (tmp->rdev 5199 && !test_bit(Faulty, &tmp->rdev->flags) 5200 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 5201 unsigned long flags; 5202 spin_lock_irqsave(&conf->device_lock, flags); 5203 mddev->degraded--; 5204 spin_unlock_irqrestore(&conf->device_lock, flags); 5205 } 5206 } 5207 print_raid5_conf(conf); 5208 return 0; 5209 } 5210 5211 static int raid5_remove_disk(mddev_t *mddev, int number) 5212 { 5213 raid5_conf_t *conf = mddev->private; 5214 int err = 0; 5215 mdk_rdev_t *rdev; 5216 struct disk_info *p = conf->disks + number; 5217 5218 print_raid5_conf(conf); 5219 rdev = p->rdev; 5220 if (rdev) { 5221 if (number >= conf->raid_disks && 5222 conf->reshape_progress == MaxSector) 5223 clear_bit(In_sync, &rdev->flags); 5224 5225 if (test_bit(In_sync, &rdev->flags) || 5226 atomic_read(&rdev->nr_pending)) { 5227 err = -EBUSY; 5228 goto abort; 5229 } 5230 /* Only remove non-faulty devices if recovery 5231 * isn't possible. 5232 */ 5233 if (!test_bit(Faulty, &rdev->flags) && 5234 mddev->degraded <= conf->max_degraded && 5235 number < conf->raid_disks) { 5236 err = -EBUSY; 5237 goto abort; 5238 } 5239 p->rdev = NULL; 5240 synchronize_rcu(); 5241 if (atomic_read(&rdev->nr_pending)) { 5242 /* lost the race, try later */ 5243 err = -EBUSY; 5244 p->rdev = rdev; 5245 } 5246 } 5247 abort: 5248 5249 print_raid5_conf(conf); 5250 return err; 5251 } 5252 5253 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 5254 { 5255 raid5_conf_t *conf = mddev->private; 5256 int err = -EEXIST; 5257 int disk; 5258 struct disk_info *p; 5259 int first = 0; 5260 int last = conf->raid_disks - 1; 5261 5262 if (mddev->degraded > conf->max_degraded) 5263 /* no point adding a device */ 5264 return -EINVAL; 5265 5266 if (rdev->raid_disk >= 0) 5267 first = last = rdev->raid_disk; 5268 5269 /* 5270 * find the disk ... but prefer rdev->saved_raid_disk 5271 * if possible. 5272 */ 5273 if (rdev->saved_raid_disk >= 0 && 5274 rdev->saved_raid_disk >= first && 5275 conf->disks[rdev->saved_raid_disk].rdev == NULL) 5276 disk = rdev->saved_raid_disk; 5277 else 5278 disk = first; 5279 for ( ; disk <= last ; disk++) 5280 if ((p=conf->disks + disk)->rdev == NULL) { 5281 clear_bit(In_sync, &rdev->flags); 5282 rdev->raid_disk = disk; 5283 err = 0; 5284 if (rdev->saved_raid_disk != disk) 5285 conf->fullsync = 1; 5286 rcu_assign_pointer(p->rdev, rdev); 5287 break; 5288 } 5289 print_raid5_conf(conf); 5290 return err; 5291 } 5292 5293 static int raid5_resize(mddev_t *mddev, sector_t sectors) 5294 { 5295 /* no resync is happening, and there is enough space 5296 * on all devices, so we can resize. 5297 * We need to make sure resync covers any new space. 5298 * If the array is shrinking we should possibly wait until 5299 * any io in the removed space completes, but it hardly seems 5300 * worth it. 5301 */ 5302 sectors &= ~((sector_t)mddev->chunk_sectors - 1); 5303 md_set_array_sectors(mddev, raid5_size(mddev, sectors, 5304 mddev->raid_disks)); 5305 if (mddev->array_sectors > 5306 raid5_size(mddev, sectors, mddev->raid_disks)) 5307 return -EINVAL; 5308 set_capacity(mddev->gendisk, mddev->array_sectors); 5309 mddev->changed = 1; 5310 revalidate_disk(mddev->gendisk); 5311 if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) { 5312 mddev->recovery_cp = mddev->dev_sectors; 5313 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 5314 } 5315 mddev->dev_sectors = sectors; 5316 mddev->resync_max_sectors = sectors; 5317 return 0; 5318 } 5319 5320 static int check_stripe_cache(mddev_t *mddev) 5321 { 5322 /* Can only proceed if there are plenty of stripe_heads. 5323 * We need a minimum of one full stripe,, and for sensible progress 5324 * it is best to have about 4 times that. 5325 * If we require 4 times, then the default 256 4K stripe_heads will 5326 * allow for chunk sizes up to 256K, which is probably OK. 5327 * If the chunk size is greater, user-space should request more 5328 * stripe_heads first. 5329 */ 5330 raid5_conf_t *conf = mddev->private; 5331 if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4 5332 > conf->max_nr_stripes || 5333 ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4 5334 > conf->max_nr_stripes) { 5335 printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n", 5336 ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9) 5337 / STRIPE_SIZE)*4); 5338 return 0; 5339 } 5340 return 1; 5341 } 5342 5343 static int check_reshape(mddev_t *mddev) 5344 { 5345 raid5_conf_t *conf = mddev->private; 5346 5347 if (mddev->delta_disks == 0 && 5348 mddev->new_layout == mddev->layout && 5349 mddev->new_chunk_sectors == mddev->chunk_sectors) 5350 return 0; /* nothing to do */ 5351 if (mddev->bitmap) 5352 /* Cannot grow a bitmap yet */ 5353 return -EBUSY; 5354 if (mddev->degraded > conf->max_degraded) 5355 return -EINVAL; 5356 if (mddev->delta_disks < 0) { 5357 /* We might be able to shrink, but the devices must 5358 * be made bigger first. 5359 * For raid6, 4 is the minimum size. 5360 * Otherwise 2 is the minimum 5361 */ 5362 int min = 2; 5363 if (mddev->level == 6) 5364 min = 4; 5365 if (mddev->raid_disks + mddev->delta_disks < min) 5366 return -EINVAL; 5367 } 5368 5369 if (!check_stripe_cache(mddev)) 5370 return -ENOSPC; 5371 5372 return resize_stripes(conf, conf->raid_disks + mddev->delta_disks); 5373 } 5374 5375 static int raid5_start_reshape(mddev_t *mddev) 5376 { 5377 raid5_conf_t *conf = mddev->private; 5378 mdk_rdev_t *rdev; 5379 int spares = 0; 5380 int added_devices = 0; 5381 unsigned long flags; 5382 5383 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 5384 return -EBUSY; 5385 5386 if (!check_stripe_cache(mddev)) 5387 return -ENOSPC; 5388 5389 list_for_each_entry(rdev, &mddev->disks, same_set) 5390 if (rdev->raid_disk < 0 && 5391 !test_bit(Faulty, &rdev->flags)) 5392 spares++; 5393 5394 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded) 5395 /* Not enough devices even to make a degraded array 5396 * of that size 5397 */ 5398 return -EINVAL; 5399 5400 /* Refuse to reduce size of the array. Any reductions in 5401 * array size must be through explicit setting of array_size 5402 * attribute. 5403 */ 5404 if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks) 5405 < mddev->array_sectors) { 5406 printk(KERN_ERR "md: %s: array size must be reduced " 5407 "before number of disks\n", mdname(mddev)); 5408 return -EINVAL; 5409 } 5410 5411 atomic_set(&conf->reshape_stripes, 0); 5412 spin_lock_irq(&conf->device_lock); 5413 conf->previous_raid_disks = conf->raid_disks; 5414 conf->raid_disks += mddev->delta_disks; 5415 conf->prev_chunk_sectors = conf->chunk_sectors; 5416 conf->chunk_sectors = mddev->new_chunk_sectors; 5417 conf->prev_algo = conf->algorithm; 5418 conf->algorithm = mddev->new_layout; 5419 if (mddev->delta_disks < 0) 5420 conf->reshape_progress = raid5_size(mddev, 0, 0); 5421 else 5422 conf->reshape_progress = 0; 5423 conf->reshape_safe = conf->reshape_progress; 5424 conf->generation++; 5425 spin_unlock_irq(&conf->device_lock); 5426 5427 /* Add some new drives, as many as will fit. 5428 * We know there are enough to make the newly sized array work. 5429 */ 5430 list_for_each_entry(rdev, &mddev->disks, same_set) 5431 if (rdev->raid_disk < 0 && 5432 !test_bit(Faulty, &rdev->flags)) { 5433 if (raid5_add_disk(mddev, rdev) == 0) { 5434 char nm[20]; 5435 if (rdev->raid_disk >= conf->previous_raid_disks) 5436 set_bit(In_sync, &rdev->flags); 5437 else 5438 rdev->recovery_offset = 0; 5439 added_devices++; 5440 sprintf(nm, "rd%d", rdev->raid_disk); 5441 if (sysfs_create_link(&mddev->kobj, 5442 &rdev->kobj, nm)) 5443 printk(KERN_WARNING 5444 "raid5: failed to create " 5445 " link %s for %s\n", 5446 nm, mdname(mddev)); 5447 } else 5448 break; 5449 } 5450 5451 if (mddev->delta_disks > 0) { 5452 spin_lock_irqsave(&conf->device_lock, flags); 5453 mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) 5454 - added_devices; 5455 spin_unlock_irqrestore(&conf->device_lock, flags); 5456 } 5457 mddev->raid_disks = conf->raid_disks; 5458 mddev->reshape_position = conf->reshape_progress; 5459 set_bit(MD_CHANGE_DEVS, &mddev->flags); 5460 5461 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 5462 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 5463 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 5464 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 5465 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 5466 "reshape"); 5467 if (!mddev->sync_thread) { 5468 mddev->recovery = 0; 5469 spin_lock_irq(&conf->device_lock); 5470 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; 5471 conf->reshape_progress = MaxSector; 5472 spin_unlock_irq(&conf->device_lock); 5473 return -EAGAIN; 5474 } 5475 conf->reshape_checkpoint = jiffies; 5476 md_wakeup_thread(mddev->sync_thread); 5477 md_new_event(mddev); 5478 return 0; 5479 } 5480 5481 /* This is called from the reshape thread and should make any 5482 * changes needed in 'conf' 5483 */ 5484 static void end_reshape(raid5_conf_t *conf) 5485 { 5486 5487 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) { 5488 5489 spin_lock_irq(&conf->device_lock); 5490 conf->previous_raid_disks = conf->raid_disks; 5491 conf->reshape_progress = MaxSector; 5492 spin_unlock_irq(&conf->device_lock); 5493 wake_up(&conf->wait_for_overlap); 5494 5495 /* read-ahead size must cover two whole stripes, which is 5496 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 5497 */ 5498 { 5499 int data_disks = conf->raid_disks - conf->max_degraded; 5500 int stripe = data_disks * ((conf->chunk_sectors << 9) 5501 / PAGE_SIZE); 5502 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 5503 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 5504 } 5505 } 5506 } 5507 5508 /* This is called from the raid5d thread with mddev_lock held. 5509 * It makes config changes to the device. 5510 */ 5511 static void raid5_finish_reshape(mddev_t *mddev) 5512 { 5513 raid5_conf_t *conf = mddev->private; 5514 5515 if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { 5516 5517 if (mddev->delta_disks > 0) { 5518 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0)); 5519 set_capacity(mddev->gendisk, mddev->array_sectors); 5520 mddev->changed = 1; 5521 revalidate_disk(mddev->gendisk); 5522 } else { 5523 int d; 5524 mddev->degraded = conf->raid_disks; 5525 for (d = 0; d < conf->raid_disks ; d++) 5526 if (conf->disks[d].rdev && 5527 test_bit(In_sync, 5528 &conf->disks[d].rdev->flags)) 5529 mddev->degraded--; 5530 for (d = conf->raid_disks ; 5531 d < conf->raid_disks - mddev->delta_disks; 5532 d++) { 5533 mdk_rdev_t *rdev = conf->disks[d].rdev; 5534 if (rdev && raid5_remove_disk(mddev, d) == 0) { 5535 char nm[20]; 5536 sprintf(nm, "rd%d", rdev->raid_disk); 5537 sysfs_remove_link(&mddev->kobj, nm); 5538 rdev->raid_disk = -1; 5539 } 5540 } 5541 } 5542 mddev->layout = conf->algorithm; 5543 mddev->chunk_sectors = conf->chunk_sectors; 5544 mddev->reshape_position = MaxSector; 5545 mddev->delta_disks = 0; 5546 } 5547 } 5548 5549 static void raid5_quiesce(mddev_t *mddev, int state) 5550 { 5551 raid5_conf_t *conf = mddev->private; 5552 5553 switch(state) { 5554 case 2: /* resume for a suspend */ 5555 wake_up(&conf->wait_for_overlap); 5556 break; 5557 5558 case 1: /* stop all writes */ 5559 spin_lock_irq(&conf->device_lock); 5560 /* '2' tells resync/reshape to pause so that all 5561 * active stripes can drain 5562 */ 5563 conf->quiesce = 2; 5564 wait_event_lock_irq(conf->wait_for_stripe, 5565 atomic_read(&conf->active_stripes) == 0 && 5566 atomic_read(&conf->active_aligned_reads) == 0, 5567 conf->device_lock, /* nothing */); 5568 conf->quiesce = 1; 5569 spin_unlock_irq(&conf->device_lock); 5570 /* allow reshape to continue */ 5571 wake_up(&conf->wait_for_overlap); 5572 break; 5573 5574 case 0: /* re-enable writes */ 5575 spin_lock_irq(&conf->device_lock); 5576 conf->quiesce = 0; 5577 wake_up(&conf->wait_for_stripe); 5578 wake_up(&conf->wait_for_overlap); 5579 spin_unlock_irq(&conf->device_lock); 5580 break; 5581 } 5582 } 5583 5584 5585 static void *raid5_takeover_raid1(mddev_t *mddev) 5586 { 5587 int chunksect; 5588 5589 if (mddev->raid_disks != 2 || 5590 mddev->degraded > 1) 5591 return ERR_PTR(-EINVAL); 5592 5593 /* Should check if there are write-behind devices? */ 5594 5595 chunksect = 64*2; /* 64K by default */ 5596 5597 /* The array must be an exact multiple of chunksize */ 5598 while (chunksect && (mddev->array_sectors & (chunksect-1))) 5599 chunksect >>= 1; 5600 5601 if ((chunksect<<9) < STRIPE_SIZE) 5602 /* array size does not allow a suitable chunk size */ 5603 return ERR_PTR(-EINVAL); 5604 5605 mddev->new_level = 5; 5606 mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC; 5607 mddev->new_chunk_sectors = chunksect; 5608 5609 return setup_conf(mddev); 5610 } 5611 5612 static void *raid5_takeover_raid6(mddev_t *mddev) 5613 { 5614 int new_layout; 5615 5616 switch (mddev->layout) { 5617 case ALGORITHM_LEFT_ASYMMETRIC_6: 5618 new_layout = ALGORITHM_LEFT_ASYMMETRIC; 5619 break; 5620 case ALGORITHM_RIGHT_ASYMMETRIC_6: 5621 new_layout = ALGORITHM_RIGHT_ASYMMETRIC; 5622 break; 5623 case ALGORITHM_LEFT_SYMMETRIC_6: 5624 new_layout = ALGORITHM_LEFT_SYMMETRIC; 5625 break; 5626 case ALGORITHM_RIGHT_SYMMETRIC_6: 5627 new_layout = ALGORITHM_RIGHT_SYMMETRIC; 5628 break; 5629 case ALGORITHM_PARITY_0_6: 5630 new_layout = ALGORITHM_PARITY_0; 5631 break; 5632 case ALGORITHM_PARITY_N: 5633 new_layout = ALGORITHM_PARITY_N; 5634 break; 5635 default: 5636 return ERR_PTR(-EINVAL); 5637 } 5638 mddev->new_level = 5; 5639 mddev->new_layout = new_layout; 5640 mddev->delta_disks = -1; 5641 mddev->raid_disks -= 1; 5642 return setup_conf(mddev); 5643 } 5644 5645 5646 static int raid5_check_reshape(mddev_t *mddev) 5647 { 5648 /* For a 2-drive array, the layout and chunk size can be changed 5649 * immediately as not restriping is needed. 5650 * For larger arrays we record the new value - after validation 5651 * to be used by a reshape pass. 5652 */ 5653 raid5_conf_t *conf = mddev->private; 5654 int new_chunk = mddev->new_chunk_sectors; 5655 5656 if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout)) 5657 return -EINVAL; 5658 if (new_chunk > 0) { 5659 if (!is_power_of_2(new_chunk)) 5660 return -EINVAL; 5661 if (new_chunk < (PAGE_SIZE>>9)) 5662 return -EINVAL; 5663 if (mddev->array_sectors & (new_chunk-1)) 5664 /* not factor of array size */ 5665 return -EINVAL; 5666 } 5667 5668 /* They look valid */ 5669 5670 if (mddev->raid_disks == 2) { 5671 /* can make the change immediately */ 5672 if (mddev->new_layout >= 0) { 5673 conf->algorithm = mddev->new_layout; 5674 mddev->layout = mddev->new_layout; 5675 } 5676 if (new_chunk > 0) { 5677 conf->chunk_sectors = new_chunk ; 5678 mddev->chunk_sectors = new_chunk; 5679 } 5680 set_bit(MD_CHANGE_DEVS, &mddev->flags); 5681 md_wakeup_thread(mddev->thread); 5682 } 5683 return check_reshape(mddev); 5684 } 5685 5686 static int raid6_check_reshape(mddev_t *mddev) 5687 { 5688 int new_chunk = mddev->new_chunk_sectors; 5689 5690 if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout)) 5691 return -EINVAL; 5692 if (new_chunk > 0) { 5693 if (!is_power_of_2(new_chunk)) 5694 return -EINVAL; 5695 if (new_chunk < (PAGE_SIZE >> 9)) 5696 return -EINVAL; 5697 if (mddev->array_sectors & (new_chunk-1)) 5698 /* not factor of array size */ 5699 return -EINVAL; 5700 } 5701 5702 /* They look valid */ 5703 return check_reshape(mddev); 5704 } 5705 5706 static void *raid5_takeover(mddev_t *mddev) 5707 { 5708 /* raid5 can take over: 5709 * raid0 - if all devices are the same - make it a raid4 layout 5710 * raid1 - if there are two drives. We need to know the chunk size 5711 * raid4 - trivial - just use a raid4 layout. 5712 * raid6 - Providing it is a *_6 layout 5713 */ 5714 5715 if (mddev->level == 1) 5716 return raid5_takeover_raid1(mddev); 5717 if (mddev->level == 4) { 5718 mddev->new_layout = ALGORITHM_PARITY_N; 5719 mddev->new_level = 5; 5720 return setup_conf(mddev); 5721 } 5722 if (mddev->level == 6) 5723 return raid5_takeover_raid6(mddev); 5724 5725 return ERR_PTR(-EINVAL); 5726 } 5727 5728 5729 static struct mdk_personality raid5_personality; 5730 5731 static void *raid6_takeover(mddev_t *mddev) 5732 { 5733 /* Currently can only take over a raid5. We map the 5734 * personality to an equivalent raid6 personality 5735 * with the Q block at the end. 5736 */ 5737 int new_layout; 5738 5739 if (mddev->pers != &raid5_personality) 5740 return ERR_PTR(-EINVAL); 5741 if (mddev->degraded > 1) 5742 return ERR_PTR(-EINVAL); 5743 if (mddev->raid_disks > 253) 5744 return ERR_PTR(-EINVAL); 5745 if (mddev->raid_disks < 3) 5746 return ERR_PTR(-EINVAL); 5747 5748 switch (mddev->layout) { 5749 case ALGORITHM_LEFT_ASYMMETRIC: 5750 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6; 5751 break; 5752 case ALGORITHM_RIGHT_ASYMMETRIC: 5753 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6; 5754 break; 5755 case ALGORITHM_LEFT_SYMMETRIC: 5756 new_layout = ALGORITHM_LEFT_SYMMETRIC_6; 5757 break; 5758 case ALGORITHM_RIGHT_SYMMETRIC: 5759 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6; 5760 break; 5761 case ALGORITHM_PARITY_0: 5762 new_layout = ALGORITHM_PARITY_0_6; 5763 break; 5764 case ALGORITHM_PARITY_N: 5765 new_layout = ALGORITHM_PARITY_N; 5766 break; 5767 default: 5768 return ERR_PTR(-EINVAL); 5769 } 5770 mddev->new_level = 6; 5771 mddev->new_layout = new_layout; 5772 mddev->delta_disks = 1; 5773 mddev->raid_disks += 1; 5774 return setup_conf(mddev); 5775 } 5776 5777 5778 static struct mdk_personality raid6_personality = 5779 { 5780 .name = "raid6", 5781 .level = 6, 5782 .owner = THIS_MODULE, 5783 .make_request = make_request, 5784 .run = run, 5785 .stop = stop, 5786 .status = status, 5787 .error_handler = error, 5788 .hot_add_disk = raid5_add_disk, 5789 .hot_remove_disk= raid5_remove_disk, 5790 .spare_active = raid5_spare_active, 5791 .sync_request = sync_request, 5792 .resize = raid5_resize, 5793 .size = raid5_size, 5794 .check_reshape = raid6_check_reshape, 5795 .start_reshape = raid5_start_reshape, 5796 .finish_reshape = raid5_finish_reshape, 5797 .quiesce = raid5_quiesce, 5798 .takeover = raid6_takeover, 5799 }; 5800 static struct mdk_personality raid5_personality = 5801 { 5802 .name = "raid5", 5803 .level = 5, 5804 .owner = THIS_MODULE, 5805 .make_request = make_request, 5806 .run = run, 5807 .stop = stop, 5808 .status = status, 5809 .error_handler = error, 5810 .hot_add_disk = raid5_add_disk, 5811 .hot_remove_disk= raid5_remove_disk, 5812 .spare_active = raid5_spare_active, 5813 .sync_request = sync_request, 5814 .resize = raid5_resize, 5815 .size = raid5_size, 5816 .check_reshape = raid5_check_reshape, 5817 .start_reshape = raid5_start_reshape, 5818 .finish_reshape = raid5_finish_reshape, 5819 .quiesce = raid5_quiesce, 5820 .takeover = raid5_takeover, 5821 }; 5822 5823 static struct mdk_personality raid4_personality = 5824 { 5825 .name = "raid4", 5826 .level = 4, 5827 .owner = THIS_MODULE, 5828 .make_request = make_request, 5829 .run = run, 5830 .stop = stop, 5831 .status = status, 5832 .error_handler = error, 5833 .hot_add_disk = raid5_add_disk, 5834 .hot_remove_disk= raid5_remove_disk, 5835 .spare_active = raid5_spare_active, 5836 .sync_request = sync_request, 5837 .resize = raid5_resize, 5838 .size = raid5_size, 5839 .check_reshape = raid5_check_reshape, 5840 .start_reshape = raid5_start_reshape, 5841 .finish_reshape = raid5_finish_reshape, 5842 .quiesce = raid5_quiesce, 5843 }; 5844 5845 static int __init raid5_init(void) 5846 { 5847 register_md_personality(&raid6_personality); 5848 register_md_personality(&raid5_personality); 5849 register_md_personality(&raid4_personality); 5850 return 0; 5851 } 5852 5853 static void raid5_exit(void) 5854 { 5855 unregister_md_personality(&raid6_personality); 5856 unregister_md_personality(&raid5_personality); 5857 unregister_md_personality(&raid4_personality); 5858 } 5859 5860 module_init(raid5_init); 5861 module_exit(raid5_exit); 5862 MODULE_LICENSE("GPL"); 5863 MODULE_ALIAS("md-personality-4"); /* RAID5 */ 5864 MODULE_ALIAS("md-raid5"); 5865 MODULE_ALIAS("md-raid4"); 5866 MODULE_ALIAS("md-level-5"); 5867 MODULE_ALIAS("md-level-4"); 5868 MODULE_ALIAS("md-personality-8"); /* RAID6 */ 5869 MODULE_ALIAS("md-raid6"); 5870 MODULE_ALIAS("md-level-6"); 5871 5872 /* This used to be two separate modules, they were: */ 5873 MODULE_ALIAS("raid5"); 5874 MODULE_ALIAS("raid6"); 5875