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 <linux/slab.h> 54 #include "md.h" 55 #include "raid5.h" 56 #include "raid0.h" 57 #include "bitmap.h" 58 59 /* 60 * Stripe cache 61 */ 62 63 #define NR_STRIPES 256 64 #define STRIPE_SIZE PAGE_SIZE 65 #define STRIPE_SHIFT (PAGE_SHIFT - 9) 66 #define STRIPE_SECTORS (STRIPE_SIZE>>9) 67 #define IO_THRESHOLD 1 68 #define BYPASS_THRESHOLD 1 69 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) 70 #define HASH_MASK (NR_HASH - 1) 71 72 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])) 73 74 /* bio's attached to a stripe+device for I/O are linked together in bi_sector 75 * order without overlap. There may be several bio's per stripe+device, and 76 * a bio could span several devices. 77 * When walking this list for a particular stripe+device, we must never proceed 78 * beyond a bio that extends past this device, as the next bio might no longer 79 * be valid. 80 * This macro is used to determine the 'next' bio in the list, given the sector 81 * of the current stripe+device 82 */ 83 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL) 84 /* 85 * The following can be used to debug the driver 86 */ 87 #define RAID5_PARANOIA 1 88 #if RAID5_PARANOIA && defined(CONFIG_SMP) 89 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock) 90 #else 91 # define CHECK_DEVLOCK() 92 #endif 93 94 #ifdef DEBUG 95 #define inline 96 #define __inline__ 97 #endif 98 99 #define printk_rl(args...) ((void) (printk_ratelimit() && printk(args))) 100 101 /* 102 * We maintain a biased count of active stripes in the bottom 16 bits of 103 * bi_phys_segments, and a count of processed stripes in the upper 16 bits 104 */ 105 static inline int raid5_bi_phys_segments(struct bio *bio) 106 { 107 return bio->bi_phys_segments & 0xffff; 108 } 109 110 static inline int raid5_bi_hw_segments(struct bio *bio) 111 { 112 return (bio->bi_phys_segments >> 16) & 0xffff; 113 } 114 115 static inline int raid5_dec_bi_phys_segments(struct bio *bio) 116 { 117 --bio->bi_phys_segments; 118 return raid5_bi_phys_segments(bio); 119 } 120 121 static inline int raid5_dec_bi_hw_segments(struct bio *bio) 122 { 123 unsigned short val = raid5_bi_hw_segments(bio); 124 125 --val; 126 bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio); 127 return val; 128 } 129 130 static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt) 131 { 132 bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16); 133 } 134 135 /* Find first data disk in a raid6 stripe */ 136 static inline int raid6_d0(struct stripe_head *sh) 137 { 138 if (sh->ddf_layout) 139 /* ddf always start from first device */ 140 return 0; 141 /* md starts just after Q block */ 142 if (sh->qd_idx == sh->disks - 1) 143 return 0; 144 else 145 return sh->qd_idx + 1; 146 } 147 static inline int raid6_next_disk(int disk, int raid_disks) 148 { 149 disk++; 150 return (disk < raid_disks) ? disk : 0; 151 } 152 153 /* When walking through the disks in a raid5, starting at raid6_d0, 154 * We need to map each disk to a 'slot', where the data disks are slot 155 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk 156 * is raid_disks-1. This help does that mapping. 157 */ 158 static int raid6_idx_to_slot(int idx, struct stripe_head *sh, 159 int *count, int syndrome_disks) 160 { 161 int slot = *count; 162 163 if (sh->ddf_layout) 164 (*count)++; 165 if (idx == sh->pd_idx) 166 return syndrome_disks; 167 if (idx == sh->qd_idx) 168 return syndrome_disks + 1; 169 if (!sh->ddf_layout) 170 (*count)++; 171 return slot; 172 } 173 174 static void return_io(struct bio *return_bi) 175 { 176 struct bio *bi = return_bi; 177 while (bi) { 178 179 return_bi = bi->bi_next; 180 bi->bi_next = NULL; 181 bi->bi_size = 0; 182 bio_endio(bi, 0); 183 bi = return_bi; 184 } 185 } 186 187 static void print_raid5_conf (raid5_conf_t *conf); 188 189 static int stripe_operations_active(struct stripe_head *sh) 190 { 191 return sh->check_state || sh->reconstruct_state || 192 test_bit(STRIPE_BIOFILL_RUN, &sh->state) || 193 test_bit(STRIPE_COMPUTE_RUN, &sh->state); 194 } 195 196 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) 197 { 198 if (atomic_dec_and_test(&sh->count)) { 199 BUG_ON(!list_empty(&sh->lru)); 200 BUG_ON(atomic_read(&conf->active_stripes)==0); 201 if (test_bit(STRIPE_HANDLE, &sh->state)) { 202 if (test_bit(STRIPE_DELAYED, &sh->state)) { 203 list_add_tail(&sh->lru, &conf->delayed_list); 204 blk_plug_device(conf->mddev->queue); 205 } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && 206 sh->bm_seq - conf->seq_write > 0) { 207 list_add_tail(&sh->lru, &conf->bitmap_list); 208 blk_plug_device(conf->mddev->queue); 209 } else { 210 clear_bit(STRIPE_BIT_DELAY, &sh->state); 211 list_add_tail(&sh->lru, &conf->handle_list); 212 } 213 md_wakeup_thread(conf->mddev->thread); 214 } else { 215 BUG_ON(stripe_operations_active(sh)); 216 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 217 atomic_dec(&conf->preread_active_stripes); 218 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) 219 md_wakeup_thread(conf->mddev->thread); 220 } 221 atomic_dec(&conf->active_stripes); 222 if (!test_bit(STRIPE_EXPANDING, &sh->state)) { 223 list_add_tail(&sh->lru, &conf->inactive_list); 224 wake_up(&conf->wait_for_stripe); 225 if (conf->retry_read_aligned) 226 md_wakeup_thread(conf->mddev->thread); 227 } 228 } 229 } 230 } 231 232 static void release_stripe(struct stripe_head *sh) 233 { 234 raid5_conf_t *conf = sh->raid_conf; 235 unsigned long flags; 236 237 spin_lock_irqsave(&conf->device_lock, flags); 238 __release_stripe(conf, sh); 239 spin_unlock_irqrestore(&conf->device_lock, flags); 240 } 241 242 static inline void remove_hash(struct stripe_head *sh) 243 { 244 pr_debug("remove_hash(), stripe %llu\n", 245 (unsigned long long)sh->sector); 246 247 hlist_del_init(&sh->hash); 248 } 249 250 static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) 251 { 252 struct hlist_head *hp = stripe_hash(conf, sh->sector); 253 254 pr_debug("insert_hash(), stripe %llu\n", 255 (unsigned long long)sh->sector); 256 257 CHECK_DEVLOCK(); 258 hlist_add_head(&sh->hash, hp); 259 } 260 261 262 /* find an idle stripe, make sure it is unhashed, and return it. */ 263 static struct stripe_head *get_free_stripe(raid5_conf_t *conf) 264 { 265 struct stripe_head *sh = NULL; 266 struct list_head *first; 267 268 CHECK_DEVLOCK(); 269 if (list_empty(&conf->inactive_list)) 270 goto out; 271 first = conf->inactive_list.next; 272 sh = list_entry(first, struct stripe_head, lru); 273 list_del_init(first); 274 remove_hash(sh); 275 atomic_inc(&conf->active_stripes); 276 out: 277 return sh; 278 } 279 280 static void shrink_buffers(struct stripe_head *sh, int num) 281 { 282 struct page *p; 283 int i; 284 285 for (i=0; i<num ; i++) { 286 p = sh->dev[i].page; 287 if (!p) 288 continue; 289 sh->dev[i].page = NULL; 290 put_page(p); 291 } 292 } 293 294 static int grow_buffers(struct stripe_head *sh, int num) 295 { 296 int i; 297 298 for (i=0; i<num; i++) { 299 struct page *page; 300 301 if (!(page = alloc_page(GFP_KERNEL))) { 302 return 1; 303 } 304 sh->dev[i].page = page; 305 } 306 return 0; 307 } 308 309 static void raid5_build_block(struct stripe_head *sh, int i, int previous); 310 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous, 311 struct stripe_head *sh); 312 313 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) 314 { 315 raid5_conf_t *conf = sh->raid_conf; 316 int i; 317 318 BUG_ON(atomic_read(&sh->count) != 0); 319 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); 320 BUG_ON(stripe_operations_active(sh)); 321 322 CHECK_DEVLOCK(); 323 pr_debug("init_stripe called, stripe %llu\n", 324 (unsigned long long)sh->sector); 325 326 remove_hash(sh); 327 328 sh->generation = conf->generation - previous; 329 sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks; 330 sh->sector = sector; 331 stripe_set_idx(sector, conf, previous, sh); 332 sh->state = 0; 333 334 335 for (i = sh->disks; i--; ) { 336 struct r5dev *dev = &sh->dev[i]; 337 338 if (dev->toread || dev->read || dev->towrite || dev->written || 339 test_bit(R5_LOCKED, &dev->flags)) { 340 printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n", 341 (unsigned long long)sh->sector, i, dev->toread, 342 dev->read, dev->towrite, dev->written, 343 test_bit(R5_LOCKED, &dev->flags)); 344 BUG(); 345 } 346 dev->flags = 0; 347 raid5_build_block(sh, i, previous); 348 } 349 insert_hash(conf, sh); 350 } 351 352 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, 353 short generation) 354 { 355 struct stripe_head *sh; 356 struct hlist_node *hn; 357 358 CHECK_DEVLOCK(); 359 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector); 360 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash) 361 if (sh->sector == sector && sh->generation == generation) 362 return sh; 363 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector); 364 return NULL; 365 } 366 367 static void unplug_slaves(mddev_t *mddev); 368 static void raid5_unplug_device(struct request_queue *q); 369 370 static struct stripe_head * 371 get_active_stripe(raid5_conf_t *conf, sector_t sector, 372 int previous, int noblock, int noquiesce) 373 { 374 struct stripe_head *sh; 375 376 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector); 377 378 spin_lock_irq(&conf->device_lock); 379 380 do { 381 wait_event_lock_irq(conf->wait_for_stripe, 382 conf->quiesce == 0 || noquiesce, 383 conf->device_lock, /* nothing */); 384 sh = __find_stripe(conf, sector, conf->generation - previous); 385 if (!sh) { 386 if (!conf->inactive_blocked) 387 sh = get_free_stripe(conf); 388 if (noblock && sh == NULL) 389 break; 390 if (!sh) { 391 conf->inactive_blocked = 1; 392 wait_event_lock_irq(conf->wait_for_stripe, 393 !list_empty(&conf->inactive_list) && 394 (atomic_read(&conf->active_stripes) 395 < (conf->max_nr_stripes *3/4) 396 || !conf->inactive_blocked), 397 conf->device_lock, 398 raid5_unplug_device(conf->mddev->queue) 399 ); 400 conf->inactive_blocked = 0; 401 } else 402 init_stripe(sh, sector, previous); 403 } else { 404 if (atomic_read(&sh->count)) { 405 BUG_ON(!list_empty(&sh->lru) 406 && !test_bit(STRIPE_EXPANDING, &sh->state)); 407 } else { 408 if (!test_bit(STRIPE_HANDLE, &sh->state)) 409 atomic_inc(&conf->active_stripes); 410 if (list_empty(&sh->lru) && 411 !test_bit(STRIPE_EXPANDING, &sh->state)) 412 BUG(); 413 list_del_init(&sh->lru); 414 } 415 } 416 } while (sh == NULL); 417 418 if (sh) 419 atomic_inc(&sh->count); 420 421 spin_unlock_irq(&conf->device_lock); 422 return sh; 423 } 424 425 static void 426 raid5_end_read_request(struct bio *bi, int error); 427 static void 428 raid5_end_write_request(struct bio *bi, int error); 429 430 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 431 { 432 raid5_conf_t *conf = sh->raid_conf; 433 int i, disks = sh->disks; 434 435 might_sleep(); 436 437 for (i = disks; i--; ) { 438 int rw; 439 struct bio *bi; 440 mdk_rdev_t *rdev; 441 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) 442 rw = WRITE; 443 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) 444 rw = READ; 445 else 446 continue; 447 448 bi = &sh->dev[i].req; 449 450 bi->bi_rw = rw; 451 if (rw == WRITE) 452 bi->bi_end_io = raid5_end_write_request; 453 else 454 bi->bi_end_io = raid5_end_read_request; 455 456 rcu_read_lock(); 457 rdev = rcu_dereference(conf->disks[i].rdev); 458 if (rdev && test_bit(Faulty, &rdev->flags)) 459 rdev = NULL; 460 if (rdev) 461 atomic_inc(&rdev->nr_pending); 462 rcu_read_unlock(); 463 464 if (rdev) { 465 if (s->syncing || s->expanding || s->expanded) 466 md_sync_acct(rdev->bdev, STRIPE_SECTORS); 467 468 set_bit(STRIPE_IO_STARTED, &sh->state); 469 470 bi->bi_bdev = rdev->bdev; 471 pr_debug("%s: for %llu schedule op %ld on disc %d\n", 472 __func__, (unsigned long long)sh->sector, 473 bi->bi_rw, i); 474 atomic_inc(&sh->count); 475 bi->bi_sector = sh->sector + rdev->data_offset; 476 bi->bi_flags = 1 << BIO_UPTODATE; 477 bi->bi_vcnt = 1; 478 bi->bi_max_vecs = 1; 479 bi->bi_idx = 0; 480 bi->bi_io_vec = &sh->dev[i].vec; 481 bi->bi_io_vec[0].bv_len = STRIPE_SIZE; 482 bi->bi_io_vec[0].bv_offset = 0; 483 bi->bi_size = STRIPE_SIZE; 484 bi->bi_next = NULL; 485 if (rw == WRITE && 486 test_bit(R5_ReWrite, &sh->dev[i].flags)) 487 atomic_add(STRIPE_SECTORS, 488 &rdev->corrected_errors); 489 generic_make_request(bi); 490 } else { 491 if (rw == WRITE) 492 set_bit(STRIPE_DEGRADED, &sh->state); 493 pr_debug("skip op %ld on disc %d for sector %llu\n", 494 bi->bi_rw, i, (unsigned long long)sh->sector); 495 clear_bit(R5_LOCKED, &sh->dev[i].flags); 496 set_bit(STRIPE_HANDLE, &sh->state); 497 } 498 } 499 } 500 501 static struct dma_async_tx_descriptor * 502 async_copy_data(int frombio, struct bio *bio, struct page *page, 503 sector_t sector, struct dma_async_tx_descriptor *tx) 504 { 505 struct bio_vec *bvl; 506 struct page *bio_page; 507 int i; 508 int page_offset; 509 struct async_submit_ctl submit; 510 enum async_tx_flags flags = 0; 511 512 if (bio->bi_sector >= sector) 513 page_offset = (signed)(bio->bi_sector - sector) * 512; 514 else 515 page_offset = (signed)(sector - bio->bi_sector) * -512; 516 517 if (frombio) 518 flags |= ASYNC_TX_FENCE; 519 init_async_submit(&submit, flags, tx, NULL, NULL, NULL); 520 521 bio_for_each_segment(bvl, bio, i) { 522 int len = bio_iovec_idx(bio, i)->bv_len; 523 int clen; 524 int b_offset = 0; 525 526 if (page_offset < 0) { 527 b_offset = -page_offset; 528 page_offset += b_offset; 529 len -= b_offset; 530 } 531 532 if (len > 0 && page_offset + len > STRIPE_SIZE) 533 clen = STRIPE_SIZE - page_offset; 534 else 535 clen = len; 536 537 if (clen > 0) { 538 b_offset += bio_iovec_idx(bio, i)->bv_offset; 539 bio_page = bio_iovec_idx(bio, i)->bv_page; 540 if (frombio) 541 tx = async_memcpy(page, bio_page, page_offset, 542 b_offset, clen, &submit); 543 else 544 tx = async_memcpy(bio_page, page, b_offset, 545 page_offset, clen, &submit); 546 } 547 /* chain the operations */ 548 submit.depend_tx = tx; 549 550 if (clen < len) /* hit end of page */ 551 break; 552 page_offset += len; 553 } 554 555 return tx; 556 } 557 558 static void ops_complete_biofill(void *stripe_head_ref) 559 { 560 struct stripe_head *sh = stripe_head_ref; 561 struct bio *return_bi = NULL; 562 raid5_conf_t *conf = sh->raid_conf; 563 int i; 564 565 pr_debug("%s: stripe %llu\n", __func__, 566 (unsigned long long)sh->sector); 567 568 /* clear completed biofills */ 569 spin_lock_irq(&conf->device_lock); 570 for (i = sh->disks; i--; ) { 571 struct r5dev *dev = &sh->dev[i]; 572 573 /* acknowledge completion of a biofill operation */ 574 /* and check if we need to reply to a read request, 575 * new R5_Wantfill requests are held off until 576 * !STRIPE_BIOFILL_RUN 577 */ 578 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) { 579 struct bio *rbi, *rbi2; 580 581 BUG_ON(!dev->read); 582 rbi = dev->read; 583 dev->read = NULL; 584 while (rbi && rbi->bi_sector < 585 dev->sector + STRIPE_SECTORS) { 586 rbi2 = r5_next_bio(rbi, dev->sector); 587 if (!raid5_dec_bi_phys_segments(rbi)) { 588 rbi->bi_next = return_bi; 589 return_bi = rbi; 590 } 591 rbi = rbi2; 592 } 593 } 594 } 595 spin_unlock_irq(&conf->device_lock); 596 clear_bit(STRIPE_BIOFILL_RUN, &sh->state); 597 598 return_io(return_bi); 599 600 set_bit(STRIPE_HANDLE, &sh->state); 601 release_stripe(sh); 602 } 603 604 static void ops_run_biofill(struct stripe_head *sh) 605 { 606 struct dma_async_tx_descriptor *tx = NULL; 607 raid5_conf_t *conf = sh->raid_conf; 608 struct async_submit_ctl submit; 609 int i; 610 611 pr_debug("%s: stripe %llu\n", __func__, 612 (unsigned long long)sh->sector); 613 614 for (i = sh->disks; i--; ) { 615 struct r5dev *dev = &sh->dev[i]; 616 if (test_bit(R5_Wantfill, &dev->flags)) { 617 struct bio *rbi; 618 spin_lock_irq(&conf->device_lock); 619 dev->read = rbi = dev->toread; 620 dev->toread = NULL; 621 spin_unlock_irq(&conf->device_lock); 622 while (rbi && rbi->bi_sector < 623 dev->sector + STRIPE_SECTORS) { 624 tx = async_copy_data(0, rbi, dev->page, 625 dev->sector, tx); 626 rbi = r5_next_bio(rbi, dev->sector); 627 } 628 } 629 } 630 631 atomic_inc(&sh->count); 632 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL); 633 async_trigger_callback(&submit); 634 } 635 636 static void mark_target_uptodate(struct stripe_head *sh, int target) 637 { 638 struct r5dev *tgt; 639 640 if (target < 0) 641 return; 642 643 tgt = &sh->dev[target]; 644 set_bit(R5_UPTODATE, &tgt->flags); 645 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 646 clear_bit(R5_Wantcompute, &tgt->flags); 647 } 648 649 static void ops_complete_compute(void *stripe_head_ref) 650 { 651 struct stripe_head *sh = stripe_head_ref; 652 653 pr_debug("%s: stripe %llu\n", __func__, 654 (unsigned long long)sh->sector); 655 656 /* mark the computed target(s) as uptodate */ 657 mark_target_uptodate(sh, sh->ops.target); 658 mark_target_uptodate(sh, sh->ops.target2); 659 660 clear_bit(STRIPE_COMPUTE_RUN, &sh->state); 661 if (sh->check_state == check_state_compute_run) 662 sh->check_state = check_state_compute_result; 663 set_bit(STRIPE_HANDLE, &sh->state); 664 release_stripe(sh); 665 } 666 667 /* return a pointer to the address conversion region of the scribble buffer */ 668 static addr_conv_t *to_addr_conv(struct stripe_head *sh, 669 struct raid5_percpu *percpu) 670 { 671 return percpu->scribble + sizeof(struct page *) * (sh->disks + 2); 672 } 673 674 static struct dma_async_tx_descriptor * 675 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu) 676 { 677 int disks = sh->disks; 678 struct page **xor_srcs = percpu->scribble; 679 int target = sh->ops.target; 680 struct r5dev *tgt = &sh->dev[target]; 681 struct page *xor_dest = tgt->page; 682 int count = 0; 683 struct dma_async_tx_descriptor *tx; 684 struct async_submit_ctl submit; 685 int i; 686 687 pr_debug("%s: stripe %llu block: %d\n", 688 __func__, (unsigned long long)sh->sector, target); 689 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 690 691 for (i = disks; i--; ) 692 if (i != target) 693 xor_srcs[count++] = sh->dev[i].page; 694 695 atomic_inc(&sh->count); 696 697 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL, 698 ops_complete_compute, sh, to_addr_conv(sh, percpu)); 699 if (unlikely(count == 1)) 700 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit); 701 else 702 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit); 703 704 return tx; 705 } 706 707 /* set_syndrome_sources - populate source buffers for gen_syndrome 708 * @srcs - (struct page *) array of size sh->disks 709 * @sh - stripe_head to parse 710 * 711 * Populates srcs in proper layout order for the stripe and returns the 712 * 'count' of sources to be used in a call to async_gen_syndrome. The P 713 * destination buffer is recorded in srcs[count] and the Q destination 714 * is recorded in srcs[count+1]]. 715 */ 716 static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh) 717 { 718 int disks = sh->disks; 719 int syndrome_disks = sh->ddf_layout ? disks : (disks - 2); 720 int d0_idx = raid6_d0(sh); 721 int count; 722 int i; 723 724 for (i = 0; i < disks; i++) 725 srcs[i] = NULL; 726 727 count = 0; 728 i = d0_idx; 729 do { 730 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks); 731 732 srcs[slot] = sh->dev[i].page; 733 i = raid6_next_disk(i, disks); 734 } while (i != d0_idx); 735 736 return syndrome_disks; 737 } 738 739 static struct dma_async_tx_descriptor * 740 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu) 741 { 742 int disks = sh->disks; 743 struct page **blocks = percpu->scribble; 744 int target; 745 int qd_idx = sh->qd_idx; 746 struct dma_async_tx_descriptor *tx; 747 struct async_submit_ctl submit; 748 struct r5dev *tgt; 749 struct page *dest; 750 int i; 751 int count; 752 753 if (sh->ops.target < 0) 754 target = sh->ops.target2; 755 else if (sh->ops.target2 < 0) 756 target = sh->ops.target; 757 else 758 /* we should only have one valid target */ 759 BUG(); 760 BUG_ON(target < 0); 761 pr_debug("%s: stripe %llu block: %d\n", 762 __func__, (unsigned long long)sh->sector, target); 763 764 tgt = &sh->dev[target]; 765 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 766 dest = tgt->page; 767 768 atomic_inc(&sh->count); 769 770 if (target == qd_idx) { 771 count = set_syndrome_sources(blocks, sh); 772 blocks[count] = NULL; /* regenerating p is not necessary */ 773 BUG_ON(blocks[count+1] != dest); /* q should already be set */ 774 init_async_submit(&submit, ASYNC_TX_FENCE, NULL, 775 ops_complete_compute, sh, 776 to_addr_conv(sh, percpu)); 777 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit); 778 } else { 779 /* Compute any data- or p-drive using XOR */ 780 count = 0; 781 for (i = disks; i-- ; ) { 782 if (i == target || i == qd_idx) 783 continue; 784 blocks[count++] = sh->dev[i].page; 785 } 786 787 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, 788 NULL, ops_complete_compute, sh, 789 to_addr_conv(sh, percpu)); 790 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit); 791 } 792 793 return tx; 794 } 795 796 static struct dma_async_tx_descriptor * 797 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu) 798 { 799 int i, count, disks = sh->disks; 800 int syndrome_disks = sh->ddf_layout ? disks : disks-2; 801 int d0_idx = raid6_d0(sh); 802 int faila = -1, failb = -1; 803 int target = sh->ops.target; 804 int target2 = sh->ops.target2; 805 struct r5dev *tgt = &sh->dev[target]; 806 struct r5dev *tgt2 = &sh->dev[target2]; 807 struct dma_async_tx_descriptor *tx; 808 struct page **blocks = percpu->scribble; 809 struct async_submit_ctl submit; 810 811 pr_debug("%s: stripe %llu block1: %d block2: %d\n", 812 __func__, (unsigned long long)sh->sector, target, target2); 813 BUG_ON(target < 0 || target2 < 0); 814 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); 815 BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags)); 816 817 /* we need to open-code set_syndrome_sources to handle the 818 * slot number conversion for 'faila' and 'failb' 819 */ 820 for (i = 0; i < disks ; i++) 821 blocks[i] = NULL; 822 count = 0; 823 i = d0_idx; 824 do { 825 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks); 826 827 blocks[slot] = sh->dev[i].page; 828 829 if (i == target) 830 faila = slot; 831 if (i == target2) 832 failb = slot; 833 i = raid6_next_disk(i, disks); 834 } while (i != d0_idx); 835 836 BUG_ON(faila == failb); 837 if (failb < faila) 838 swap(faila, failb); 839 pr_debug("%s: stripe: %llu faila: %d failb: %d\n", 840 __func__, (unsigned long long)sh->sector, faila, failb); 841 842 atomic_inc(&sh->count); 843 844 if (failb == syndrome_disks+1) { 845 /* Q disk is one of the missing disks */ 846 if (faila == syndrome_disks) { 847 /* Missing P+Q, just recompute */ 848 init_async_submit(&submit, ASYNC_TX_FENCE, NULL, 849 ops_complete_compute, sh, 850 to_addr_conv(sh, percpu)); 851 return async_gen_syndrome(blocks, 0, syndrome_disks+2, 852 STRIPE_SIZE, &submit); 853 } else { 854 struct page *dest; 855 int data_target; 856 int qd_idx = sh->qd_idx; 857 858 /* Missing D+Q: recompute D from P, then recompute Q */ 859 if (target == qd_idx) 860 data_target = target2; 861 else 862 data_target = target; 863 864 count = 0; 865 for (i = disks; i-- ; ) { 866 if (i == data_target || i == qd_idx) 867 continue; 868 blocks[count++] = sh->dev[i].page; 869 } 870 dest = sh->dev[data_target].page; 871 init_async_submit(&submit, 872 ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, 873 NULL, NULL, NULL, 874 to_addr_conv(sh, percpu)); 875 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, 876 &submit); 877 878 count = set_syndrome_sources(blocks, sh); 879 init_async_submit(&submit, ASYNC_TX_FENCE, tx, 880 ops_complete_compute, sh, 881 to_addr_conv(sh, percpu)); 882 return async_gen_syndrome(blocks, 0, count+2, 883 STRIPE_SIZE, &submit); 884 } 885 } else { 886 init_async_submit(&submit, ASYNC_TX_FENCE, NULL, 887 ops_complete_compute, sh, 888 to_addr_conv(sh, percpu)); 889 if (failb == syndrome_disks) { 890 /* We're missing D+P. */ 891 return async_raid6_datap_recov(syndrome_disks+2, 892 STRIPE_SIZE, faila, 893 blocks, &submit); 894 } else { 895 /* We're missing D+D. */ 896 return async_raid6_2data_recov(syndrome_disks+2, 897 STRIPE_SIZE, faila, failb, 898 blocks, &submit); 899 } 900 } 901 } 902 903 904 static void ops_complete_prexor(void *stripe_head_ref) 905 { 906 struct stripe_head *sh = stripe_head_ref; 907 908 pr_debug("%s: stripe %llu\n", __func__, 909 (unsigned long long)sh->sector); 910 } 911 912 static struct dma_async_tx_descriptor * 913 ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu, 914 struct dma_async_tx_descriptor *tx) 915 { 916 int disks = sh->disks; 917 struct page **xor_srcs = percpu->scribble; 918 int count = 0, pd_idx = sh->pd_idx, i; 919 struct async_submit_ctl submit; 920 921 /* existing parity data subtracted */ 922 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 923 924 pr_debug("%s: stripe %llu\n", __func__, 925 (unsigned long long)sh->sector); 926 927 for (i = disks; i--; ) { 928 struct r5dev *dev = &sh->dev[i]; 929 /* Only process blocks that are known to be uptodate */ 930 if (test_bit(R5_Wantdrain, &dev->flags)) 931 xor_srcs[count++] = dev->page; 932 } 933 934 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx, 935 ops_complete_prexor, sh, to_addr_conv(sh, percpu)); 936 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit); 937 938 return tx; 939 } 940 941 static struct dma_async_tx_descriptor * 942 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) 943 { 944 int disks = sh->disks; 945 int i; 946 947 pr_debug("%s: stripe %llu\n", __func__, 948 (unsigned long long)sh->sector); 949 950 for (i = disks; i--; ) { 951 struct r5dev *dev = &sh->dev[i]; 952 struct bio *chosen; 953 954 if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) { 955 struct bio *wbi; 956 957 spin_lock(&sh->lock); 958 chosen = dev->towrite; 959 dev->towrite = NULL; 960 BUG_ON(dev->written); 961 wbi = dev->written = chosen; 962 spin_unlock(&sh->lock); 963 964 while (wbi && wbi->bi_sector < 965 dev->sector + STRIPE_SECTORS) { 966 tx = async_copy_data(1, wbi, dev->page, 967 dev->sector, tx); 968 wbi = r5_next_bio(wbi, dev->sector); 969 } 970 } 971 } 972 973 return tx; 974 } 975 976 static void ops_complete_reconstruct(void *stripe_head_ref) 977 { 978 struct stripe_head *sh = stripe_head_ref; 979 int disks = sh->disks; 980 int pd_idx = sh->pd_idx; 981 int qd_idx = sh->qd_idx; 982 int i; 983 984 pr_debug("%s: stripe %llu\n", __func__, 985 (unsigned long long)sh->sector); 986 987 for (i = disks; i--; ) { 988 struct r5dev *dev = &sh->dev[i]; 989 990 if (dev->written || i == pd_idx || i == qd_idx) 991 set_bit(R5_UPTODATE, &dev->flags); 992 } 993 994 if (sh->reconstruct_state == reconstruct_state_drain_run) 995 sh->reconstruct_state = reconstruct_state_drain_result; 996 else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) 997 sh->reconstruct_state = reconstruct_state_prexor_drain_result; 998 else { 999 BUG_ON(sh->reconstruct_state != reconstruct_state_run); 1000 sh->reconstruct_state = reconstruct_state_result; 1001 } 1002 1003 set_bit(STRIPE_HANDLE, &sh->state); 1004 release_stripe(sh); 1005 } 1006 1007 static void 1008 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu, 1009 struct dma_async_tx_descriptor *tx) 1010 { 1011 int disks = sh->disks; 1012 struct page **xor_srcs = percpu->scribble; 1013 struct async_submit_ctl submit; 1014 int count = 0, pd_idx = sh->pd_idx, i; 1015 struct page *xor_dest; 1016 int prexor = 0; 1017 unsigned long flags; 1018 1019 pr_debug("%s: stripe %llu\n", __func__, 1020 (unsigned long long)sh->sector); 1021 1022 /* check if prexor is active which means only process blocks 1023 * that are part of a read-modify-write (written) 1024 */ 1025 if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) { 1026 prexor = 1; 1027 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; 1028 for (i = disks; i--; ) { 1029 struct r5dev *dev = &sh->dev[i]; 1030 if (dev->written) 1031 xor_srcs[count++] = dev->page; 1032 } 1033 } else { 1034 xor_dest = sh->dev[pd_idx].page; 1035 for (i = disks; i--; ) { 1036 struct r5dev *dev = &sh->dev[i]; 1037 if (i != pd_idx) 1038 xor_srcs[count++] = dev->page; 1039 } 1040 } 1041 1042 /* 1/ if we prexor'd then the dest is reused as a source 1043 * 2/ if we did not prexor then we are redoing the parity 1044 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST 1045 * for the synchronous xor case 1046 */ 1047 flags = ASYNC_TX_ACK | 1048 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST); 1049 1050 atomic_inc(&sh->count); 1051 1052 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh, 1053 to_addr_conv(sh, percpu)); 1054 if (unlikely(count == 1)) 1055 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit); 1056 else 1057 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit); 1058 } 1059 1060 static void 1061 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu, 1062 struct dma_async_tx_descriptor *tx) 1063 { 1064 struct async_submit_ctl submit; 1065 struct page **blocks = percpu->scribble; 1066 int count; 1067 1068 pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); 1069 1070 count = set_syndrome_sources(blocks, sh); 1071 1072 atomic_inc(&sh->count); 1073 1074 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct, 1075 sh, to_addr_conv(sh, percpu)); 1076 async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit); 1077 } 1078 1079 static void ops_complete_check(void *stripe_head_ref) 1080 { 1081 struct stripe_head *sh = stripe_head_ref; 1082 1083 pr_debug("%s: stripe %llu\n", __func__, 1084 (unsigned long long)sh->sector); 1085 1086 sh->check_state = check_state_check_result; 1087 set_bit(STRIPE_HANDLE, &sh->state); 1088 release_stripe(sh); 1089 } 1090 1091 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu) 1092 { 1093 int disks = sh->disks; 1094 int pd_idx = sh->pd_idx; 1095 int qd_idx = sh->qd_idx; 1096 struct page *xor_dest; 1097 struct page **xor_srcs = percpu->scribble; 1098 struct dma_async_tx_descriptor *tx; 1099 struct async_submit_ctl submit; 1100 int count; 1101 int i; 1102 1103 pr_debug("%s: stripe %llu\n", __func__, 1104 (unsigned long long)sh->sector); 1105 1106 count = 0; 1107 xor_dest = sh->dev[pd_idx].page; 1108 xor_srcs[count++] = xor_dest; 1109 for (i = disks; i--; ) { 1110 if (i == pd_idx || i == qd_idx) 1111 continue; 1112 xor_srcs[count++] = sh->dev[i].page; 1113 } 1114 1115 init_async_submit(&submit, 0, NULL, NULL, NULL, 1116 to_addr_conv(sh, percpu)); 1117 tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, 1118 &sh->ops.zero_sum_result, &submit); 1119 1120 atomic_inc(&sh->count); 1121 init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL); 1122 tx = async_trigger_callback(&submit); 1123 } 1124 1125 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp) 1126 { 1127 struct page **srcs = percpu->scribble; 1128 struct async_submit_ctl submit; 1129 int count; 1130 1131 pr_debug("%s: stripe %llu checkp: %d\n", __func__, 1132 (unsigned long long)sh->sector, checkp); 1133 1134 count = set_syndrome_sources(srcs, sh); 1135 if (!checkp) 1136 srcs[count] = NULL; 1137 1138 atomic_inc(&sh->count); 1139 init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check, 1140 sh, to_addr_conv(sh, percpu)); 1141 async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE, 1142 &sh->ops.zero_sum_result, percpu->spare_page, &submit); 1143 } 1144 1145 static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 1146 { 1147 int overlap_clear = 0, i, disks = sh->disks; 1148 struct dma_async_tx_descriptor *tx = NULL; 1149 raid5_conf_t *conf = sh->raid_conf; 1150 int level = conf->level; 1151 struct raid5_percpu *percpu; 1152 unsigned long cpu; 1153 1154 cpu = get_cpu(); 1155 percpu = per_cpu_ptr(conf->percpu, cpu); 1156 if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) { 1157 ops_run_biofill(sh); 1158 overlap_clear++; 1159 } 1160 1161 if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) { 1162 if (level < 6) 1163 tx = ops_run_compute5(sh, percpu); 1164 else { 1165 if (sh->ops.target2 < 0 || sh->ops.target < 0) 1166 tx = ops_run_compute6_1(sh, percpu); 1167 else 1168 tx = ops_run_compute6_2(sh, percpu); 1169 } 1170 /* terminate the chain if reconstruct is not set to be run */ 1171 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) 1172 async_tx_ack(tx); 1173 } 1174 1175 if (test_bit(STRIPE_OP_PREXOR, &ops_request)) 1176 tx = ops_run_prexor(sh, percpu, tx); 1177 1178 if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) { 1179 tx = ops_run_biodrain(sh, tx); 1180 overlap_clear++; 1181 } 1182 1183 if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) { 1184 if (level < 6) 1185 ops_run_reconstruct5(sh, percpu, tx); 1186 else 1187 ops_run_reconstruct6(sh, percpu, tx); 1188 } 1189 1190 if (test_bit(STRIPE_OP_CHECK, &ops_request)) { 1191 if (sh->check_state == check_state_run) 1192 ops_run_check_p(sh, percpu); 1193 else if (sh->check_state == check_state_run_q) 1194 ops_run_check_pq(sh, percpu, 0); 1195 else if (sh->check_state == check_state_run_pq) 1196 ops_run_check_pq(sh, percpu, 1); 1197 else 1198 BUG(); 1199 } 1200 1201 if (overlap_clear) 1202 for (i = disks; i--; ) { 1203 struct r5dev *dev = &sh->dev[i]; 1204 if (test_and_clear_bit(R5_Overlap, &dev->flags)) 1205 wake_up(&sh->raid_conf->wait_for_overlap); 1206 } 1207 put_cpu(); 1208 } 1209 1210 #ifdef CONFIG_MULTICORE_RAID456 1211 static void async_run_ops(void *param, async_cookie_t cookie) 1212 { 1213 struct stripe_head *sh = param; 1214 unsigned long ops_request = sh->ops.request; 1215 1216 clear_bit_unlock(STRIPE_OPS_REQ_PENDING, &sh->state); 1217 wake_up(&sh->ops.wait_for_ops); 1218 1219 __raid_run_ops(sh, ops_request); 1220 release_stripe(sh); 1221 } 1222 1223 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 1224 { 1225 /* since handle_stripe can be called outside of raid5d context 1226 * we need to ensure sh->ops.request is de-staged before another 1227 * request arrives 1228 */ 1229 wait_event(sh->ops.wait_for_ops, 1230 !test_and_set_bit_lock(STRIPE_OPS_REQ_PENDING, &sh->state)); 1231 sh->ops.request = ops_request; 1232 1233 atomic_inc(&sh->count); 1234 async_schedule(async_run_ops, sh); 1235 } 1236 #else 1237 #define raid_run_ops __raid_run_ops 1238 #endif 1239 1240 static int grow_one_stripe(raid5_conf_t *conf) 1241 { 1242 struct stripe_head *sh; 1243 int disks = max(conf->raid_disks, conf->previous_raid_disks); 1244 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); 1245 if (!sh) 1246 return 0; 1247 memset(sh, 0, sizeof(*sh) + (disks-1)*sizeof(struct r5dev)); 1248 sh->raid_conf = conf; 1249 spin_lock_init(&sh->lock); 1250 #ifdef CONFIG_MULTICORE_RAID456 1251 init_waitqueue_head(&sh->ops.wait_for_ops); 1252 #endif 1253 1254 if (grow_buffers(sh, disks)) { 1255 shrink_buffers(sh, disks); 1256 kmem_cache_free(conf->slab_cache, sh); 1257 return 0; 1258 } 1259 /* we just created an active stripe so... */ 1260 atomic_set(&sh->count, 1); 1261 atomic_inc(&conf->active_stripes); 1262 INIT_LIST_HEAD(&sh->lru); 1263 release_stripe(sh); 1264 return 1; 1265 } 1266 1267 static int grow_stripes(raid5_conf_t *conf, int num) 1268 { 1269 struct kmem_cache *sc; 1270 int devs = max(conf->raid_disks, conf->previous_raid_disks); 1271 1272 sprintf(conf->cache_name[0], 1273 "raid%d-%s", conf->level, mdname(conf->mddev)); 1274 sprintf(conf->cache_name[1], 1275 "raid%d-%s-alt", conf->level, mdname(conf->mddev)); 1276 conf->active_name = 0; 1277 sc = kmem_cache_create(conf->cache_name[conf->active_name], 1278 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 1279 0, 0, NULL); 1280 if (!sc) 1281 return 1; 1282 conf->slab_cache = sc; 1283 conf->pool_size = devs; 1284 while (num--) 1285 if (!grow_one_stripe(conf)) 1286 return 1; 1287 return 0; 1288 } 1289 1290 /** 1291 * scribble_len - return the required size of the scribble region 1292 * @num - total number of disks in the array 1293 * 1294 * The size must be enough to contain: 1295 * 1/ a struct page pointer for each device in the array +2 1296 * 2/ room to convert each entry in (1) to its corresponding dma 1297 * (dma_map_page()) or page (page_address()) address. 1298 * 1299 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we 1300 * calculate over all devices (not just the data blocks), using zeros in place 1301 * of the P and Q blocks. 1302 */ 1303 static size_t scribble_len(int num) 1304 { 1305 size_t len; 1306 1307 len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2); 1308 1309 return len; 1310 } 1311 1312 static int resize_stripes(raid5_conf_t *conf, int newsize) 1313 { 1314 /* Make all the stripes able to hold 'newsize' devices. 1315 * New slots in each stripe get 'page' set to a new page. 1316 * 1317 * This happens in stages: 1318 * 1/ create a new kmem_cache and allocate the required number of 1319 * stripe_heads. 1320 * 2/ gather all the old stripe_heads and tranfer the pages across 1321 * to the new stripe_heads. This will have the side effect of 1322 * freezing the array as once all stripe_heads have been collected, 1323 * no IO will be possible. Old stripe heads are freed once their 1324 * pages have been transferred over, and the old kmem_cache is 1325 * freed when all stripes are done. 1326 * 3/ reallocate conf->disks to be suitable bigger. If this fails, 1327 * we simple return a failre status - no need to clean anything up. 1328 * 4/ allocate new pages for the new slots in the new stripe_heads. 1329 * If this fails, we don't bother trying the shrink the 1330 * stripe_heads down again, we just leave them as they are. 1331 * As each stripe_head is processed the new one is released into 1332 * active service. 1333 * 1334 * Once step2 is started, we cannot afford to wait for a write, 1335 * so we use GFP_NOIO allocations. 1336 */ 1337 struct stripe_head *osh, *nsh; 1338 LIST_HEAD(newstripes); 1339 struct disk_info *ndisks; 1340 unsigned long cpu; 1341 int err; 1342 struct kmem_cache *sc; 1343 int i; 1344 1345 if (newsize <= conf->pool_size) 1346 return 0; /* never bother to shrink */ 1347 1348 err = md_allow_write(conf->mddev); 1349 if (err) 1350 return err; 1351 1352 /* Step 1 */ 1353 sc = kmem_cache_create(conf->cache_name[1-conf->active_name], 1354 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev), 1355 0, 0, NULL); 1356 if (!sc) 1357 return -ENOMEM; 1358 1359 for (i = conf->max_nr_stripes; i; i--) { 1360 nsh = kmem_cache_alloc(sc, GFP_KERNEL); 1361 if (!nsh) 1362 break; 1363 1364 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev)); 1365 1366 nsh->raid_conf = conf; 1367 spin_lock_init(&nsh->lock); 1368 #ifdef CONFIG_MULTICORE_RAID456 1369 init_waitqueue_head(&nsh->ops.wait_for_ops); 1370 #endif 1371 1372 list_add(&nsh->lru, &newstripes); 1373 } 1374 if (i) { 1375 /* didn't get enough, give up */ 1376 while (!list_empty(&newstripes)) { 1377 nsh = list_entry(newstripes.next, struct stripe_head, lru); 1378 list_del(&nsh->lru); 1379 kmem_cache_free(sc, nsh); 1380 } 1381 kmem_cache_destroy(sc); 1382 return -ENOMEM; 1383 } 1384 /* Step 2 - Must use GFP_NOIO now. 1385 * OK, we have enough stripes, start collecting inactive 1386 * stripes and copying them over 1387 */ 1388 list_for_each_entry(nsh, &newstripes, lru) { 1389 spin_lock_irq(&conf->device_lock); 1390 wait_event_lock_irq(conf->wait_for_stripe, 1391 !list_empty(&conf->inactive_list), 1392 conf->device_lock, 1393 unplug_slaves(conf->mddev) 1394 ); 1395 osh = get_free_stripe(conf); 1396 spin_unlock_irq(&conf->device_lock); 1397 atomic_set(&nsh->count, 1); 1398 for(i=0; i<conf->pool_size; i++) 1399 nsh->dev[i].page = osh->dev[i].page; 1400 for( ; i<newsize; i++) 1401 nsh->dev[i].page = NULL; 1402 kmem_cache_free(conf->slab_cache, osh); 1403 } 1404 kmem_cache_destroy(conf->slab_cache); 1405 1406 /* Step 3. 1407 * At this point, we are holding all the stripes so the array 1408 * is completely stalled, so now is a good time to resize 1409 * conf->disks and the scribble region 1410 */ 1411 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO); 1412 if (ndisks) { 1413 for (i=0; i<conf->raid_disks; i++) 1414 ndisks[i] = conf->disks[i]; 1415 kfree(conf->disks); 1416 conf->disks = ndisks; 1417 } else 1418 err = -ENOMEM; 1419 1420 get_online_cpus(); 1421 conf->scribble_len = scribble_len(newsize); 1422 for_each_present_cpu(cpu) { 1423 struct raid5_percpu *percpu; 1424 void *scribble; 1425 1426 percpu = per_cpu_ptr(conf->percpu, cpu); 1427 scribble = kmalloc(conf->scribble_len, GFP_NOIO); 1428 1429 if (scribble) { 1430 kfree(percpu->scribble); 1431 percpu->scribble = scribble; 1432 } else { 1433 err = -ENOMEM; 1434 break; 1435 } 1436 } 1437 put_online_cpus(); 1438 1439 /* Step 4, return new stripes to service */ 1440 while(!list_empty(&newstripes)) { 1441 nsh = list_entry(newstripes.next, struct stripe_head, lru); 1442 list_del_init(&nsh->lru); 1443 1444 for (i=conf->raid_disks; i < newsize; i++) 1445 if (nsh->dev[i].page == NULL) { 1446 struct page *p = alloc_page(GFP_NOIO); 1447 nsh->dev[i].page = p; 1448 if (!p) 1449 err = -ENOMEM; 1450 } 1451 release_stripe(nsh); 1452 } 1453 /* critical section pass, GFP_NOIO no longer needed */ 1454 1455 conf->slab_cache = sc; 1456 conf->active_name = 1-conf->active_name; 1457 conf->pool_size = newsize; 1458 return err; 1459 } 1460 1461 static int drop_one_stripe(raid5_conf_t *conf) 1462 { 1463 struct stripe_head *sh; 1464 1465 spin_lock_irq(&conf->device_lock); 1466 sh = get_free_stripe(conf); 1467 spin_unlock_irq(&conf->device_lock); 1468 if (!sh) 1469 return 0; 1470 BUG_ON(atomic_read(&sh->count)); 1471 shrink_buffers(sh, conf->pool_size); 1472 kmem_cache_free(conf->slab_cache, sh); 1473 atomic_dec(&conf->active_stripes); 1474 return 1; 1475 } 1476 1477 static void shrink_stripes(raid5_conf_t *conf) 1478 { 1479 while (drop_one_stripe(conf)) 1480 ; 1481 1482 if (conf->slab_cache) 1483 kmem_cache_destroy(conf->slab_cache); 1484 conf->slab_cache = NULL; 1485 } 1486 1487 static void raid5_end_read_request(struct bio * bi, int error) 1488 { 1489 struct stripe_head *sh = bi->bi_private; 1490 raid5_conf_t *conf = sh->raid_conf; 1491 int disks = sh->disks, i; 1492 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 1493 char b[BDEVNAME_SIZE]; 1494 mdk_rdev_t *rdev; 1495 1496 1497 for (i=0 ; i<disks; i++) 1498 if (bi == &sh->dev[i].req) 1499 break; 1500 1501 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n", 1502 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 1503 uptodate); 1504 if (i == disks) { 1505 BUG(); 1506 return; 1507 } 1508 1509 if (uptodate) { 1510 set_bit(R5_UPTODATE, &sh->dev[i].flags); 1511 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 1512 rdev = conf->disks[i].rdev; 1513 printk_rl(KERN_INFO "md/raid:%s: read error corrected" 1514 " (%lu sectors at %llu on %s)\n", 1515 mdname(conf->mddev), STRIPE_SECTORS, 1516 (unsigned long long)(sh->sector 1517 + rdev->data_offset), 1518 bdevname(rdev->bdev, b)); 1519 clear_bit(R5_ReadError, &sh->dev[i].flags); 1520 clear_bit(R5_ReWrite, &sh->dev[i].flags); 1521 } 1522 if (atomic_read(&conf->disks[i].rdev->read_errors)) 1523 atomic_set(&conf->disks[i].rdev->read_errors, 0); 1524 } else { 1525 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b); 1526 int retry = 0; 1527 rdev = conf->disks[i].rdev; 1528 1529 clear_bit(R5_UPTODATE, &sh->dev[i].flags); 1530 atomic_inc(&rdev->read_errors); 1531 if (conf->mddev->degraded >= conf->max_degraded) 1532 printk_rl(KERN_WARNING 1533 "md/raid:%s: read error not correctable " 1534 "(sector %llu on %s).\n", 1535 mdname(conf->mddev), 1536 (unsigned long long)(sh->sector 1537 + rdev->data_offset), 1538 bdn); 1539 else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) 1540 /* Oh, no!!! */ 1541 printk_rl(KERN_WARNING 1542 "md/raid:%s: read error NOT corrected!! " 1543 "(sector %llu on %s).\n", 1544 mdname(conf->mddev), 1545 (unsigned long long)(sh->sector 1546 + rdev->data_offset), 1547 bdn); 1548 else if (atomic_read(&rdev->read_errors) 1549 > conf->max_nr_stripes) 1550 printk(KERN_WARNING 1551 "md/raid:%s: Too many read errors, failing device %s.\n", 1552 mdname(conf->mddev), bdn); 1553 else 1554 retry = 1; 1555 if (retry) 1556 set_bit(R5_ReadError, &sh->dev[i].flags); 1557 else { 1558 clear_bit(R5_ReadError, &sh->dev[i].flags); 1559 clear_bit(R5_ReWrite, &sh->dev[i].flags); 1560 md_error(conf->mddev, rdev); 1561 } 1562 } 1563 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 1564 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1565 set_bit(STRIPE_HANDLE, &sh->state); 1566 release_stripe(sh); 1567 } 1568 1569 static void raid5_end_write_request(struct bio *bi, int error) 1570 { 1571 struct stripe_head *sh = bi->bi_private; 1572 raid5_conf_t *conf = sh->raid_conf; 1573 int disks = sh->disks, i; 1574 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 1575 1576 for (i=0 ; i<disks; i++) 1577 if (bi == &sh->dev[i].req) 1578 break; 1579 1580 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n", 1581 (unsigned long long)sh->sector, i, atomic_read(&sh->count), 1582 uptodate); 1583 if (i == disks) { 1584 BUG(); 1585 return; 1586 } 1587 1588 if (!uptodate) 1589 md_error(conf->mddev, conf->disks[i].rdev); 1590 1591 rdev_dec_pending(conf->disks[i].rdev, conf->mddev); 1592 1593 clear_bit(R5_LOCKED, &sh->dev[i].flags); 1594 set_bit(STRIPE_HANDLE, &sh->state); 1595 release_stripe(sh); 1596 } 1597 1598 1599 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous); 1600 1601 static void raid5_build_block(struct stripe_head *sh, int i, int previous) 1602 { 1603 struct r5dev *dev = &sh->dev[i]; 1604 1605 bio_init(&dev->req); 1606 dev->req.bi_io_vec = &dev->vec; 1607 dev->req.bi_vcnt++; 1608 dev->req.bi_max_vecs++; 1609 dev->vec.bv_page = dev->page; 1610 dev->vec.bv_len = STRIPE_SIZE; 1611 dev->vec.bv_offset = 0; 1612 1613 dev->req.bi_sector = sh->sector; 1614 dev->req.bi_private = sh; 1615 1616 dev->flags = 0; 1617 dev->sector = compute_blocknr(sh, i, previous); 1618 } 1619 1620 static void error(mddev_t *mddev, mdk_rdev_t *rdev) 1621 { 1622 char b[BDEVNAME_SIZE]; 1623 raid5_conf_t *conf = mddev->private; 1624 pr_debug("raid456: error called\n"); 1625 1626 if (!test_bit(Faulty, &rdev->flags)) { 1627 set_bit(MD_CHANGE_DEVS, &mddev->flags); 1628 if (test_and_clear_bit(In_sync, &rdev->flags)) { 1629 unsigned long flags; 1630 spin_lock_irqsave(&conf->device_lock, flags); 1631 mddev->degraded++; 1632 spin_unlock_irqrestore(&conf->device_lock, flags); 1633 /* 1634 * if recovery was running, make sure it aborts. 1635 */ 1636 set_bit(MD_RECOVERY_INTR, &mddev->recovery); 1637 } 1638 set_bit(Faulty, &rdev->flags); 1639 printk(KERN_ALERT 1640 "md/raid:%s: Disk failure on %s, disabling device.\n" 1641 KERN_ALERT 1642 "md/raid:%s: Operation continuing on %d devices.\n", 1643 mdname(mddev), 1644 bdevname(rdev->bdev, b), 1645 mdname(mddev), 1646 conf->raid_disks - mddev->degraded); 1647 } 1648 } 1649 1650 /* 1651 * Input: a 'big' sector number, 1652 * Output: index of the data and parity disk, and the sector # in them. 1653 */ 1654 static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, 1655 int previous, int *dd_idx, 1656 struct stripe_head *sh) 1657 { 1658 sector_t stripe, stripe2; 1659 sector_t chunk_number; 1660 unsigned int chunk_offset; 1661 int pd_idx, qd_idx; 1662 int ddf_layout = 0; 1663 sector_t new_sector; 1664 int algorithm = previous ? conf->prev_algo 1665 : conf->algorithm; 1666 int sectors_per_chunk = previous ? conf->prev_chunk_sectors 1667 : conf->chunk_sectors; 1668 int raid_disks = previous ? conf->previous_raid_disks 1669 : conf->raid_disks; 1670 int data_disks = raid_disks - conf->max_degraded; 1671 1672 /* First compute the information on this sector */ 1673 1674 /* 1675 * Compute the chunk number and the sector offset inside the chunk 1676 */ 1677 chunk_offset = sector_div(r_sector, sectors_per_chunk); 1678 chunk_number = r_sector; 1679 1680 /* 1681 * Compute the stripe number 1682 */ 1683 stripe = chunk_number; 1684 *dd_idx = sector_div(stripe, data_disks); 1685 stripe2 = stripe; 1686 /* 1687 * Select the parity disk based on the user selected algorithm. 1688 */ 1689 pd_idx = qd_idx = ~0; 1690 switch(conf->level) { 1691 case 4: 1692 pd_idx = data_disks; 1693 break; 1694 case 5: 1695 switch (algorithm) { 1696 case ALGORITHM_LEFT_ASYMMETRIC: 1697 pd_idx = data_disks - sector_div(stripe2, raid_disks); 1698 if (*dd_idx >= pd_idx) 1699 (*dd_idx)++; 1700 break; 1701 case ALGORITHM_RIGHT_ASYMMETRIC: 1702 pd_idx = sector_div(stripe2, raid_disks); 1703 if (*dd_idx >= pd_idx) 1704 (*dd_idx)++; 1705 break; 1706 case ALGORITHM_LEFT_SYMMETRIC: 1707 pd_idx = data_disks - sector_div(stripe2, raid_disks); 1708 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; 1709 break; 1710 case ALGORITHM_RIGHT_SYMMETRIC: 1711 pd_idx = sector_div(stripe2, raid_disks); 1712 *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; 1713 break; 1714 case ALGORITHM_PARITY_0: 1715 pd_idx = 0; 1716 (*dd_idx)++; 1717 break; 1718 case ALGORITHM_PARITY_N: 1719 pd_idx = data_disks; 1720 break; 1721 default: 1722 BUG(); 1723 } 1724 break; 1725 case 6: 1726 1727 switch (algorithm) { 1728 case ALGORITHM_LEFT_ASYMMETRIC: 1729 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks); 1730 qd_idx = pd_idx + 1; 1731 if (pd_idx == raid_disks-1) { 1732 (*dd_idx)++; /* Q D D D P */ 1733 qd_idx = 0; 1734 } else if (*dd_idx >= pd_idx) 1735 (*dd_idx) += 2; /* D D P Q D */ 1736 break; 1737 case ALGORITHM_RIGHT_ASYMMETRIC: 1738 pd_idx = sector_div(stripe2, raid_disks); 1739 qd_idx = pd_idx + 1; 1740 if (pd_idx == raid_disks-1) { 1741 (*dd_idx)++; /* Q D D D P */ 1742 qd_idx = 0; 1743 } else if (*dd_idx >= pd_idx) 1744 (*dd_idx) += 2; /* D D P Q D */ 1745 break; 1746 case ALGORITHM_LEFT_SYMMETRIC: 1747 pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks); 1748 qd_idx = (pd_idx + 1) % raid_disks; 1749 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks; 1750 break; 1751 case ALGORITHM_RIGHT_SYMMETRIC: 1752 pd_idx = sector_div(stripe2, raid_disks); 1753 qd_idx = (pd_idx + 1) % raid_disks; 1754 *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks; 1755 break; 1756 1757 case ALGORITHM_PARITY_0: 1758 pd_idx = 0; 1759 qd_idx = 1; 1760 (*dd_idx) += 2; 1761 break; 1762 case ALGORITHM_PARITY_N: 1763 pd_idx = data_disks; 1764 qd_idx = data_disks + 1; 1765 break; 1766 1767 case ALGORITHM_ROTATING_ZERO_RESTART: 1768 /* Exactly the same as RIGHT_ASYMMETRIC, but or 1769 * of blocks for computing Q is different. 1770 */ 1771 pd_idx = sector_div(stripe2, raid_disks); 1772 qd_idx = pd_idx + 1; 1773 if (pd_idx == raid_disks-1) { 1774 (*dd_idx)++; /* Q D D D P */ 1775 qd_idx = 0; 1776 } else if (*dd_idx >= pd_idx) 1777 (*dd_idx) += 2; /* D D P Q D */ 1778 ddf_layout = 1; 1779 break; 1780 1781 case ALGORITHM_ROTATING_N_RESTART: 1782 /* Same a left_asymmetric, by first stripe is 1783 * D D D P Q rather than 1784 * Q D D D P 1785 */ 1786 stripe2 += 1; 1787 pd_idx = raid_disks - 1 - sector_div(stripe2, 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 - sector_div(stripe2, 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 - sector_div(stripe2, 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 = sector_div(stripe2, 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 - sector_div(stripe2, 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 = sector_div(stripe2, 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 default: 1839 BUG(); 1840 } 1841 break; 1842 } 1843 1844 if (sh) { 1845 sh->pd_idx = pd_idx; 1846 sh->qd_idx = qd_idx; 1847 sh->ddf_layout = ddf_layout; 1848 } 1849 /* 1850 * Finally, compute the new sector number 1851 */ 1852 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; 1853 return new_sector; 1854 } 1855 1856 1857 static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous) 1858 { 1859 raid5_conf_t *conf = sh->raid_conf; 1860 int raid_disks = sh->disks; 1861 int data_disks = raid_disks - conf->max_degraded; 1862 sector_t new_sector = sh->sector, check; 1863 int sectors_per_chunk = previous ? conf->prev_chunk_sectors 1864 : conf->chunk_sectors; 1865 int algorithm = previous ? conf->prev_algo 1866 : conf->algorithm; 1867 sector_t stripe; 1868 int chunk_offset; 1869 sector_t chunk_number; 1870 int dummy1, dd_idx = i; 1871 sector_t r_sector; 1872 struct stripe_head sh2; 1873 1874 1875 chunk_offset = sector_div(new_sector, sectors_per_chunk); 1876 stripe = new_sector; 1877 1878 if (i == sh->pd_idx) 1879 return 0; 1880 switch(conf->level) { 1881 case 4: break; 1882 case 5: 1883 switch (algorithm) { 1884 case ALGORITHM_LEFT_ASYMMETRIC: 1885 case ALGORITHM_RIGHT_ASYMMETRIC: 1886 if (i > sh->pd_idx) 1887 i--; 1888 break; 1889 case ALGORITHM_LEFT_SYMMETRIC: 1890 case ALGORITHM_RIGHT_SYMMETRIC: 1891 if (i < sh->pd_idx) 1892 i += raid_disks; 1893 i -= (sh->pd_idx + 1); 1894 break; 1895 case ALGORITHM_PARITY_0: 1896 i -= 1; 1897 break; 1898 case ALGORITHM_PARITY_N: 1899 break; 1900 default: 1901 BUG(); 1902 } 1903 break; 1904 case 6: 1905 if (i == sh->qd_idx) 1906 return 0; /* It is the Q disk */ 1907 switch (algorithm) { 1908 case ALGORITHM_LEFT_ASYMMETRIC: 1909 case ALGORITHM_RIGHT_ASYMMETRIC: 1910 case ALGORITHM_ROTATING_ZERO_RESTART: 1911 case ALGORITHM_ROTATING_N_RESTART: 1912 if (sh->pd_idx == raid_disks-1) 1913 i--; /* Q D D D P */ 1914 else if (i > sh->pd_idx) 1915 i -= 2; /* D D P Q D */ 1916 break; 1917 case ALGORITHM_LEFT_SYMMETRIC: 1918 case ALGORITHM_RIGHT_SYMMETRIC: 1919 if (sh->pd_idx == raid_disks-1) 1920 i--; /* Q D D D P */ 1921 else { 1922 /* D D P Q D */ 1923 if (i < sh->pd_idx) 1924 i += raid_disks; 1925 i -= (sh->pd_idx + 2); 1926 } 1927 break; 1928 case ALGORITHM_PARITY_0: 1929 i -= 2; 1930 break; 1931 case ALGORITHM_PARITY_N: 1932 break; 1933 case ALGORITHM_ROTATING_N_CONTINUE: 1934 /* Like left_symmetric, but P is before Q */ 1935 if (sh->pd_idx == 0) 1936 i--; /* P D D D Q */ 1937 else { 1938 /* D D Q P D */ 1939 if (i < sh->pd_idx) 1940 i += raid_disks; 1941 i -= (sh->pd_idx + 1); 1942 } 1943 break; 1944 case ALGORITHM_LEFT_ASYMMETRIC_6: 1945 case ALGORITHM_RIGHT_ASYMMETRIC_6: 1946 if (i > sh->pd_idx) 1947 i--; 1948 break; 1949 case ALGORITHM_LEFT_SYMMETRIC_6: 1950 case ALGORITHM_RIGHT_SYMMETRIC_6: 1951 if (i < sh->pd_idx) 1952 i += data_disks + 1; 1953 i -= (sh->pd_idx + 1); 1954 break; 1955 case ALGORITHM_PARITY_0_6: 1956 i -= 1; 1957 break; 1958 default: 1959 BUG(); 1960 } 1961 break; 1962 } 1963 1964 chunk_number = stripe * data_disks + i; 1965 r_sector = chunk_number * sectors_per_chunk + chunk_offset; 1966 1967 check = raid5_compute_sector(conf, r_sector, 1968 previous, &dummy1, &sh2); 1969 if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx 1970 || sh2.qd_idx != sh->qd_idx) { 1971 printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n", 1972 mdname(conf->mddev)); 1973 return 0; 1974 } 1975 return r_sector; 1976 } 1977 1978 1979 static void 1980 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s, 1981 int rcw, int expand) 1982 { 1983 int i, pd_idx = sh->pd_idx, disks = sh->disks; 1984 raid5_conf_t *conf = sh->raid_conf; 1985 int level = conf->level; 1986 1987 if (rcw) { 1988 /* if we are not expanding this is a proper write request, and 1989 * there will be bios with new data to be drained into the 1990 * stripe cache 1991 */ 1992 if (!expand) { 1993 sh->reconstruct_state = reconstruct_state_drain_run; 1994 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); 1995 } else 1996 sh->reconstruct_state = reconstruct_state_run; 1997 1998 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request); 1999 2000 for (i = disks; i--; ) { 2001 struct r5dev *dev = &sh->dev[i]; 2002 2003 if (dev->towrite) { 2004 set_bit(R5_LOCKED, &dev->flags); 2005 set_bit(R5_Wantdrain, &dev->flags); 2006 if (!expand) 2007 clear_bit(R5_UPTODATE, &dev->flags); 2008 s->locked++; 2009 } 2010 } 2011 if (s->locked + conf->max_degraded == disks) 2012 if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state)) 2013 atomic_inc(&conf->pending_full_writes); 2014 } else { 2015 BUG_ON(level == 6); 2016 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) || 2017 test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags))); 2018 2019 sh->reconstruct_state = reconstruct_state_prexor_drain_run; 2020 set_bit(STRIPE_OP_PREXOR, &s->ops_request); 2021 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); 2022 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request); 2023 2024 for (i = disks; i--; ) { 2025 struct r5dev *dev = &sh->dev[i]; 2026 if (i == pd_idx) 2027 continue; 2028 2029 if (dev->towrite && 2030 (test_bit(R5_UPTODATE, &dev->flags) || 2031 test_bit(R5_Wantcompute, &dev->flags))) { 2032 set_bit(R5_Wantdrain, &dev->flags); 2033 set_bit(R5_LOCKED, &dev->flags); 2034 clear_bit(R5_UPTODATE, &dev->flags); 2035 s->locked++; 2036 } 2037 } 2038 } 2039 2040 /* keep the parity disk(s) locked while asynchronous operations 2041 * are in flight 2042 */ 2043 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); 2044 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 2045 s->locked++; 2046 2047 if (level == 6) { 2048 int qd_idx = sh->qd_idx; 2049 struct r5dev *dev = &sh->dev[qd_idx]; 2050 2051 set_bit(R5_LOCKED, &dev->flags); 2052 clear_bit(R5_UPTODATE, &dev->flags); 2053 s->locked++; 2054 } 2055 2056 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n", 2057 __func__, (unsigned long long)sh->sector, 2058 s->locked, s->ops_request); 2059 } 2060 2061 /* 2062 * Each stripe/dev can have one or more bion attached. 2063 * toread/towrite point to the first in a chain. 2064 * The bi_next chain must be in order. 2065 */ 2066 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) 2067 { 2068 struct bio **bip; 2069 raid5_conf_t *conf = sh->raid_conf; 2070 int firstwrite=0; 2071 2072 pr_debug("adding bh b#%llu to stripe s#%llu\n", 2073 (unsigned long long)bi->bi_sector, 2074 (unsigned long long)sh->sector); 2075 2076 2077 spin_lock(&sh->lock); 2078 spin_lock_irq(&conf->device_lock); 2079 if (forwrite) { 2080 bip = &sh->dev[dd_idx].towrite; 2081 if (*bip == NULL && sh->dev[dd_idx].written == NULL) 2082 firstwrite = 1; 2083 } else 2084 bip = &sh->dev[dd_idx].toread; 2085 while (*bip && (*bip)->bi_sector < bi->bi_sector) { 2086 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) 2087 goto overlap; 2088 bip = & (*bip)->bi_next; 2089 } 2090 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) 2091 goto overlap; 2092 2093 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next); 2094 if (*bip) 2095 bi->bi_next = *bip; 2096 *bip = bi; 2097 bi->bi_phys_segments++; 2098 spin_unlock_irq(&conf->device_lock); 2099 spin_unlock(&sh->lock); 2100 2101 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n", 2102 (unsigned long long)bi->bi_sector, 2103 (unsigned long long)sh->sector, dd_idx); 2104 2105 if (conf->mddev->bitmap && firstwrite) { 2106 bitmap_startwrite(conf->mddev->bitmap, sh->sector, 2107 STRIPE_SECTORS, 0); 2108 sh->bm_seq = conf->seq_flush+1; 2109 set_bit(STRIPE_BIT_DELAY, &sh->state); 2110 } 2111 2112 if (forwrite) { 2113 /* check if page is covered */ 2114 sector_t sector = sh->dev[dd_idx].sector; 2115 for (bi=sh->dev[dd_idx].towrite; 2116 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && 2117 bi && bi->bi_sector <= sector; 2118 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { 2119 if (bi->bi_sector + (bi->bi_size>>9) >= sector) 2120 sector = bi->bi_sector + (bi->bi_size>>9); 2121 } 2122 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) 2123 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); 2124 } 2125 return 1; 2126 2127 overlap: 2128 set_bit(R5_Overlap, &sh->dev[dd_idx].flags); 2129 spin_unlock_irq(&conf->device_lock); 2130 spin_unlock(&sh->lock); 2131 return 0; 2132 } 2133 2134 static void end_reshape(raid5_conf_t *conf); 2135 2136 static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous, 2137 struct stripe_head *sh) 2138 { 2139 int sectors_per_chunk = 2140 previous ? conf->prev_chunk_sectors : conf->chunk_sectors; 2141 int dd_idx; 2142 int chunk_offset = sector_div(stripe, sectors_per_chunk); 2143 int disks = previous ? conf->previous_raid_disks : conf->raid_disks; 2144 2145 raid5_compute_sector(conf, 2146 stripe * (disks - conf->max_degraded) 2147 *sectors_per_chunk + chunk_offset, 2148 previous, 2149 &dd_idx, sh); 2150 } 2151 2152 static void 2153 handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, 2154 struct stripe_head_state *s, int disks, 2155 struct bio **return_bi) 2156 { 2157 int i; 2158 for (i = disks; i--; ) { 2159 struct bio *bi; 2160 int bitmap_end = 0; 2161 2162 if (test_bit(R5_ReadError, &sh->dev[i].flags)) { 2163 mdk_rdev_t *rdev; 2164 rcu_read_lock(); 2165 rdev = rcu_dereference(conf->disks[i].rdev); 2166 if (rdev && test_bit(In_sync, &rdev->flags)) 2167 /* multiple read failures in one stripe */ 2168 md_error(conf->mddev, rdev); 2169 rcu_read_unlock(); 2170 } 2171 spin_lock_irq(&conf->device_lock); 2172 /* fail all writes first */ 2173 bi = sh->dev[i].towrite; 2174 sh->dev[i].towrite = NULL; 2175 if (bi) { 2176 s->to_write--; 2177 bitmap_end = 1; 2178 } 2179 2180 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 2181 wake_up(&conf->wait_for_overlap); 2182 2183 while (bi && bi->bi_sector < 2184 sh->dev[i].sector + STRIPE_SECTORS) { 2185 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); 2186 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2187 if (!raid5_dec_bi_phys_segments(bi)) { 2188 md_write_end(conf->mddev); 2189 bi->bi_next = *return_bi; 2190 *return_bi = bi; 2191 } 2192 bi = nextbi; 2193 } 2194 /* and fail all 'written' */ 2195 bi = sh->dev[i].written; 2196 sh->dev[i].written = NULL; 2197 if (bi) bitmap_end = 1; 2198 while (bi && bi->bi_sector < 2199 sh->dev[i].sector + STRIPE_SECTORS) { 2200 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); 2201 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2202 if (!raid5_dec_bi_phys_segments(bi)) { 2203 md_write_end(conf->mddev); 2204 bi->bi_next = *return_bi; 2205 *return_bi = bi; 2206 } 2207 bi = bi2; 2208 } 2209 2210 /* fail any reads if this device is non-operational and 2211 * the data has not reached the cache yet. 2212 */ 2213 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) && 2214 (!test_bit(R5_Insync, &sh->dev[i].flags) || 2215 test_bit(R5_ReadError, &sh->dev[i].flags))) { 2216 bi = sh->dev[i].toread; 2217 sh->dev[i].toread = NULL; 2218 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) 2219 wake_up(&conf->wait_for_overlap); 2220 if (bi) s->to_read--; 2221 while (bi && bi->bi_sector < 2222 sh->dev[i].sector + STRIPE_SECTORS) { 2223 struct bio *nextbi = 2224 r5_next_bio(bi, sh->dev[i].sector); 2225 clear_bit(BIO_UPTODATE, &bi->bi_flags); 2226 if (!raid5_dec_bi_phys_segments(bi)) { 2227 bi->bi_next = *return_bi; 2228 *return_bi = bi; 2229 } 2230 bi = nextbi; 2231 } 2232 } 2233 spin_unlock_irq(&conf->device_lock); 2234 if (bitmap_end) 2235 bitmap_endwrite(conf->mddev->bitmap, sh->sector, 2236 STRIPE_SECTORS, 0, 0); 2237 } 2238 2239 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) 2240 if (atomic_dec_and_test(&conf->pending_full_writes)) 2241 md_wakeup_thread(conf->mddev->thread); 2242 } 2243 2244 /* fetch_block5 - checks the given member device to see if its data needs 2245 * to be read or computed to satisfy a request. 2246 * 2247 * Returns 1 when no more member devices need to be checked, otherwise returns 2248 * 0 to tell the loop in handle_stripe_fill5 to continue 2249 */ 2250 static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s, 2251 int disk_idx, int disks) 2252 { 2253 struct r5dev *dev = &sh->dev[disk_idx]; 2254 struct r5dev *failed_dev = &sh->dev[s->failed_num]; 2255 2256 /* is the data in this block needed, and can we get it? */ 2257 if (!test_bit(R5_LOCKED, &dev->flags) && 2258 !test_bit(R5_UPTODATE, &dev->flags) && 2259 (dev->toread || 2260 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 2261 s->syncing || s->expanding || 2262 (s->failed && 2263 (failed_dev->toread || 2264 (failed_dev->towrite && 2265 !test_bit(R5_OVERWRITE, &failed_dev->flags)))))) { 2266 /* We would like to get this block, possibly by computing it, 2267 * otherwise read it if the backing disk is insync 2268 */ 2269 if ((s->uptodate == disks - 1) && 2270 (s->failed && disk_idx == s->failed_num)) { 2271 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2272 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2273 set_bit(R5_Wantcompute, &dev->flags); 2274 sh->ops.target = disk_idx; 2275 sh->ops.target2 = -1; 2276 s->req_compute = 1; 2277 /* Careful: from this point on 'uptodate' is in the eye 2278 * of raid_run_ops which services 'compute' operations 2279 * before writes. R5_Wantcompute flags a block that will 2280 * be R5_UPTODATE by the time it is needed for a 2281 * subsequent operation. 2282 */ 2283 s->uptodate++; 2284 return 1; /* uptodate + compute == disks */ 2285 } else if (test_bit(R5_Insync, &dev->flags)) { 2286 set_bit(R5_LOCKED, &dev->flags); 2287 set_bit(R5_Wantread, &dev->flags); 2288 s->locked++; 2289 pr_debug("Reading block %d (sync=%d)\n", disk_idx, 2290 s->syncing); 2291 } 2292 } 2293 2294 return 0; 2295 } 2296 2297 /** 2298 * handle_stripe_fill5 - read or compute data to satisfy pending requests. 2299 */ 2300 static void handle_stripe_fill5(struct stripe_head *sh, 2301 struct stripe_head_state *s, int disks) 2302 { 2303 int i; 2304 2305 /* look for blocks to read/compute, skip this if a compute 2306 * is already in flight, or if the stripe contents are in the 2307 * midst of changing due to a write 2308 */ 2309 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state && 2310 !sh->reconstruct_state) 2311 for (i = disks; i--; ) 2312 if (fetch_block5(sh, s, i, disks)) 2313 break; 2314 set_bit(STRIPE_HANDLE, &sh->state); 2315 } 2316 2317 /* fetch_block6 - checks the given member device to see if its data needs 2318 * to be read or computed to satisfy a request. 2319 * 2320 * Returns 1 when no more member devices need to be checked, otherwise returns 2321 * 0 to tell the loop in handle_stripe_fill6 to continue 2322 */ 2323 static int fetch_block6(struct stripe_head *sh, struct stripe_head_state *s, 2324 struct r6_state *r6s, int disk_idx, int disks) 2325 { 2326 struct r5dev *dev = &sh->dev[disk_idx]; 2327 struct r5dev *fdev[2] = { &sh->dev[r6s->failed_num[0]], 2328 &sh->dev[r6s->failed_num[1]] }; 2329 2330 if (!test_bit(R5_LOCKED, &dev->flags) && 2331 !test_bit(R5_UPTODATE, &dev->flags) && 2332 (dev->toread || 2333 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || 2334 s->syncing || s->expanding || 2335 (s->failed >= 1 && 2336 (fdev[0]->toread || s->to_write)) || 2337 (s->failed >= 2 && 2338 (fdev[1]->toread || s->to_write)))) { 2339 /* we would like to get this block, possibly by computing it, 2340 * otherwise read it if the backing disk is insync 2341 */ 2342 BUG_ON(test_bit(R5_Wantcompute, &dev->flags)); 2343 BUG_ON(test_bit(R5_Wantread, &dev->flags)); 2344 if ((s->uptodate == disks - 1) && 2345 (s->failed && (disk_idx == r6s->failed_num[0] || 2346 disk_idx == r6s->failed_num[1]))) { 2347 /* have disk failed, and we're requested to fetch it; 2348 * do compute it 2349 */ 2350 pr_debug("Computing stripe %llu block %d\n", 2351 (unsigned long long)sh->sector, disk_idx); 2352 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2353 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2354 set_bit(R5_Wantcompute, &dev->flags); 2355 sh->ops.target = disk_idx; 2356 sh->ops.target2 = -1; /* no 2nd target */ 2357 s->req_compute = 1; 2358 s->uptodate++; 2359 return 1; 2360 } else if (s->uptodate == disks-2 && s->failed >= 2) { 2361 /* Computing 2-failure is *very* expensive; only 2362 * do it if failed >= 2 2363 */ 2364 int other; 2365 for (other = disks; other--; ) { 2366 if (other == disk_idx) 2367 continue; 2368 if (!test_bit(R5_UPTODATE, 2369 &sh->dev[other].flags)) 2370 break; 2371 } 2372 BUG_ON(other < 0); 2373 pr_debug("Computing stripe %llu blocks %d,%d\n", 2374 (unsigned long long)sh->sector, 2375 disk_idx, other); 2376 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2377 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2378 set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags); 2379 set_bit(R5_Wantcompute, &sh->dev[other].flags); 2380 sh->ops.target = disk_idx; 2381 sh->ops.target2 = other; 2382 s->uptodate += 2; 2383 s->req_compute = 1; 2384 return 1; 2385 } else if (test_bit(R5_Insync, &dev->flags)) { 2386 set_bit(R5_LOCKED, &dev->flags); 2387 set_bit(R5_Wantread, &dev->flags); 2388 s->locked++; 2389 pr_debug("Reading block %d (sync=%d)\n", 2390 disk_idx, s->syncing); 2391 } 2392 } 2393 2394 return 0; 2395 } 2396 2397 /** 2398 * handle_stripe_fill6 - read or compute data to satisfy pending requests. 2399 */ 2400 static void handle_stripe_fill6(struct stripe_head *sh, 2401 struct stripe_head_state *s, struct r6_state *r6s, 2402 int disks) 2403 { 2404 int i; 2405 2406 /* look for blocks to read/compute, skip this if a compute 2407 * is already in flight, or if the stripe contents are in the 2408 * midst of changing due to a write 2409 */ 2410 if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state && 2411 !sh->reconstruct_state) 2412 for (i = disks; i--; ) 2413 if (fetch_block6(sh, s, r6s, i, disks)) 2414 break; 2415 set_bit(STRIPE_HANDLE, &sh->state); 2416 } 2417 2418 2419 /* handle_stripe_clean_event 2420 * any written block on an uptodate or failed drive can be returned. 2421 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but 2422 * never LOCKED, so we don't need to test 'failed' directly. 2423 */ 2424 static void handle_stripe_clean_event(raid5_conf_t *conf, 2425 struct stripe_head *sh, int disks, struct bio **return_bi) 2426 { 2427 int i; 2428 struct r5dev *dev; 2429 2430 for (i = disks; i--; ) 2431 if (sh->dev[i].written) { 2432 dev = &sh->dev[i]; 2433 if (!test_bit(R5_LOCKED, &dev->flags) && 2434 test_bit(R5_UPTODATE, &dev->flags)) { 2435 /* We can return any write requests */ 2436 struct bio *wbi, *wbi2; 2437 int bitmap_end = 0; 2438 pr_debug("Return write for disc %d\n", i); 2439 spin_lock_irq(&conf->device_lock); 2440 wbi = dev->written; 2441 dev->written = NULL; 2442 while (wbi && wbi->bi_sector < 2443 dev->sector + STRIPE_SECTORS) { 2444 wbi2 = r5_next_bio(wbi, dev->sector); 2445 if (!raid5_dec_bi_phys_segments(wbi)) { 2446 md_write_end(conf->mddev); 2447 wbi->bi_next = *return_bi; 2448 *return_bi = wbi; 2449 } 2450 wbi = wbi2; 2451 } 2452 if (dev->towrite == NULL) 2453 bitmap_end = 1; 2454 spin_unlock_irq(&conf->device_lock); 2455 if (bitmap_end) 2456 bitmap_endwrite(conf->mddev->bitmap, 2457 sh->sector, 2458 STRIPE_SECTORS, 2459 !test_bit(STRIPE_DEGRADED, &sh->state), 2460 0); 2461 } 2462 } 2463 2464 if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) 2465 if (atomic_dec_and_test(&conf->pending_full_writes)) 2466 md_wakeup_thread(conf->mddev->thread); 2467 } 2468 2469 static void handle_stripe_dirtying5(raid5_conf_t *conf, 2470 struct stripe_head *sh, struct stripe_head_state *s, int disks) 2471 { 2472 int rmw = 0, rcw = 0, i; 2473 for (i = disks; i--; ) { 2474 /* would I have to read this buffer for read_modify_write */ 2475 struct r5dev *dev = &sh->dev[i]; 2476 if ((dev->towrite || i == sh->pd_idx) && 2477 !test_bit(R5_LOCKED, &dev->flags) && 2478 !(test_bit(R5_UPTODATE, &dev->flags) || 2479 test_bit(R5_Wantcompute, &dev->flags))) { 2480 if (test_bit(R5_Insync, &dev->flags)) 2481 rmw++; 2482 else 2483 rmw += 2*disks; /* cannot read it */ 2484 } 2485 /* Would I have to read this buffer for reconstruct_write */ 2486 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && 2487 !test_bit(R5_LOCKED, &dev->flags) && 2488 !(test_bit(R5_UPTODATE, &dev->flags) || 2489 test_bit(R5_Wantcompute, &dev->flags))) { 2490 if (test_bit(R5_Insync, &dev->flags)) rcw++; 2491 else 2492 rcw += 2*disks; 2493 } 2494 } 2495 pr_debug("for sector %llu, rmw=%d rcw=%d\n", 2496 (unsigned long long)sh->sector, rmw, rcw); 2497 set_bit(STRIPE_HANDLE, &sh->state); 2498 if (rmw < rcw && rmw > 0) 2499 /* prefer read-modify-write, but need to get some data */ 2500 for (i = disks; i--; ) { 2501 struct r5dev *dev = &sh->dev[i]; 2502 if ((dev->towrite || i == sh->pd_idx) && 2503 !test_bit(R5_LOCKED, &dev->flags) && 2504 !(test_bit(R5_UPTODATE, &dev->flags) || 2505 test_bit(R5_Wantcompute, &dev->flags)) && 2506 test_bit(R5_Insync, &dev->flags)) { 2507 if ( 2508 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2509 pr_debug("Read_old block " 2510 "%d for r-m-w\n", i); 2511 set_bit(R5_LOCKED, &dev->flags); 2512 set_bit(R5_Wantread, &dev->flags); 2513 s->locked++; 2514 } else { 2515 set_bit(STRIPE_DELAYED, &sh->state); 2516 set_bit(STRIPE_HANDLE, &sh->state); 2517 } 2518 } 2519 } 2520 if (rcw <= rmw && rcw > 0) 2521 /* want reconstruct write, but need to get some data */ 2522 for (i = disks; i--; ) { 2523 struct r5dev *dev = &sh->dev[i]; 2524 if (!test_bit(R5_OVERWRITE, &dev->flags) && 2525 i != sh->pd_idx && 2526 !test_bit(R5_LOCKED, &dev->flags) && 2527 !(test_bit(R5_UPTODATE, &dev->flags) || 2528 test_bit(R5_Wantcompute, &dev->flags)) && 2529 test_bit(R5_Insync, &dev->flags)) { 2530 if ( 2531 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2532 pr_debug("Read_old block " 2533 "%d for Reconstruct\n", i); 2534 set_bit(R5_LOCKED, &dev->flags); 2535 set_bit(R5_Wantread, &dev->flags); 2536 s->locked++; 2537 } else { 2538 set_bit(STRIPE_DELAYED, &sh->state); 2539 set_bit(STRIPE_HANDLE, &sh->state); 2540 } 2541 } 2542 } 2543 /* now if nothing is locked, and if we have enough data, 2544 * we can start a write request 2545 */ 2546 /* since handle_stripe can be called at any time we need to handle the 2547 * case where a compute block operation has been submitted and then a 2548 * subsequent call wants to start a write request. raid_run_ops only 2549 * handles the case where compute block and reconstruct are requested 2550 * simultaneously. If this is not the case then new writes need to be 2551 * held off until the compute completes. 2552 */ 2553 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) && 2554 (s->locked == 0 && (rcw == 0 || rmw == 0) && 2555 !test_bit(STRIPE_BIT_DELAY, &sh->state))) 2556 schedule_reconstruction(sh, s, rcw == 0, 0); 2557 } 2558 2559 static void handle_stripe_dirtying6(raid5_conf_t *conf, 2560 struct stripe_head *sh, struct stripe_head_state *s, 2561 struct r6_state *r6s, int disks) 2562 { 2563 int rcw = 0, pd_idx = sh->pd_idx, i; 2564 int qd_idx = sh->qd_idx; 2565 2566 set_bit(STRIPE_HANDLE, &sh->state); 2567 for (i = disks; i--; ) { 2568 struct r5dev *dev = &sh->dev[i]; 2569 /* check if we haven't enough data */ 2570 if (!test_bit(R5_OVERWRITE, &dev->flags) && 2571 i != pd_idx && i != qd_idx && 2572 !test_bit(R5_LOCKED, &dev->flags) && 2573 !(test_bit(R5_UPTODATE, &dev->flags) || 2574 test_bit(R5_Wantcompute, &dev->flags))) { 2575 rcw++; 2576 if (!test_bit(R5_Insync, &dev->flags)) 2577 continue; /* it's a failed drive */ 2578 2579 if ( 2580 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { 2581 pr_debug("Read_old stripe %llu " 2582 "block %d for Reconstruct\n", 2583 (unsigned long long)sh->sector, i); 2584 set_bit(R5_LOCKED, &dev->flags); 2585 set_bit(R5_Wantread, &dev->flags); 2586 s->locked++; 2587 } else { 2588 pr_debug("Request delayed stripe %llu " 2589 "block %d for Reconstruct\n", 2590 (unsigned long long)sh->sector, i); 2591 set_bit(STRIPE_DELAYED, &sh->state); 2592 set_bit(STRIPE_HANDLE, &sh->state); 2593 } 2594 } 2595 } 2596 /* now if nothing is locked, and if we have enough data, we can start a 2597 * write request 2598 */ 2599 if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) && 2600 s->locked == 0 && rcw == 0 && 2601 !test_bit(STRIPE_BIT_DELAY, &sh->state)) { 2602 schedule_reconstruction(sh, s, 1, 0); 2603 } 2604 } 2605 2606 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh, 2607 struct stripe_head_state *s, int disks) 2608 { 2609 struct r5dev *dev = NULL; 2610 2611 set_bit(STRIPE_HANDLE, &sh->state); 2612 2613 switch (sh->check_state) { 2614 case check_state_idle: 2615 /* start a new check operation if there are no failures */ 2616 if (s->failed == 0) { 2617 BUG_ON(s->uptodate != disks); 2618 sh->check_state = check_state_run; 2619 set_bit(STRIPE_OP_CHECK, &s->ops_request); 2620 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags); 2621 s->uptodate--; 2622 break; 2623 } 2624 dev = &sh->dev[s->failed_num]; 2625 /* fall through */ 2626 case check_state_compute_result: 2627 sh->check_state = check_state_idle; 2628 if (!dev) 2629 dev = &sh->dev[sh->pd_idx]; 2630 2631 /* check that a write has not made the stripe insync */ 2632 if (test_bit(STRIPE_INSYNC, &sh->state)) 2633 break; 2634 2635 /* either failed parity check, or recovery is happening */ 2636 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); 2637 BUG_ON(s->uptodate != disks); 2638 2639 set_bit(R5_LOCKED, &dev->flags); 2640 s->locked++; 2641 set_bit(R5_Wantwrite, &dev->flags); 2642 2643 clear_bit(STRIPE_DEGRADED, &sh->state); 2644 set_bit(STRIPE_INSYNC, &sh->state); 2645 break; 2646 case check_state_run: 2647 break; /* we will be called again upon completion */ 2648 case check_state_check_result: 2649 sh->check_state = check_state_idle; 2650 2651 /* if a failure occurred during the check operation, leave 2652 * STRIPE_INSYNC not set and let the stripe be handled again 2653 */ 2654 if (s->failed) 2655 break; 2656 2657 /* handle a successful check operation, if parity is correct 2658 * we are done. Otherwise update the mismatch count and repair 2659 * parity if !MD_RECOVERY_CHECK 2660 */ 2661 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0) 2662 /* parity is correct (on disc, 2663 * not in buffer any more) 2664 */ 2665 set_bit(STRIPE_INSYNC, &sh->state); 2666 else { 2667 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2668 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2669 /* don't try to repair!! */ 2670 set_bit(STRIPE_INSYNC, &sh->state); 2671 else { 2672 sh->check_state = check_state_compute_run; 2673 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2674 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2675 set_bit(R5_Wantcompute, 2676 &sh->dev[sh->pd_idx].flags); 2677 sh->ops.target = sh->pd_idx; 2678 sh->ops.target2 = -1; 2679 s->uptodate++; 2680 } 2681 } 2682 break; 2683 case check_state_compute_run: 2684 break; 2685 default: 2686 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n", 2687 __func__, sh->check_state, 2688 (unsigned long long) sh->sector); 2689 BUG(); 2690 } 2691 } 2692 2693 2694 static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh, 2695 struct stripe_head_state *s, 2696 struct r6_state *r6s, int disks) 2697 { 2698 int pd_idx = sh->pd_idx; 2699 int qd_idx = sh->qd_idx; 2700 struct r5dev *dev; 2701 2702 set_bit(STRIPE_HANDLE, &sh->state); 2703 2704 BUG_ON(s->failed > 2); 2705 2706 /* Want to check and possibly repair P and Q. 2707 * However there could be one 'failed' device, in which 2708 * case we can only check one of them, possibly using the 2709 * other to generate missing data 2710 */ 2711 2712 switch (sh->check_state) { 2713 case check_state_idle: 2714 /* start a new check operation if there are < 2 failures */ 2715 if (s->failed == r6s->q_failed) { 2716 /* The only possible failed device holds Q, so it 2717 * makes sense to check P (If anything else were failed, 2718 * we would have used P to recreate it). 2719 */ 2720 sh->check_state = check_state_run; 2721 } 2722 if (!r6s->q_failed && s->failed < 2) { 2723 /* Q is not failed, and we didn't use it to generate 2724 * anything, so it makes sense to check it 2725 */ 2726 if (sh->check_state == check_state_run) 2727 sh->check_state = check_state_run_pq; 2728 else 2729 sh->check_state = check_state_run_q; 2730 } 2731 2732 /* discard potentially stale zero_sum_result */ 2733 sh->ops.zero_sum_result = 0; 2734 2735 if (sh->check_state == check_state_run) { 2736 /* async_xor_zero_sum destroys the contents of P */ 2737 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); 2738 s->uptodate--; 2739 } 2740 if (sh->check_state >= check_state_run && 2741 sh->check_state <= check_state_run_pq) { 2742 /* async_syndrome_zero_sum preserves P and Q, so 2743 * no need to mark them !uptodate here 2744 */ 2745 set_bit(STRIPE_OP_CHECK, &s->ops_request); 2746 break; 2747 } 2748 2749 /* we have 2-disk failure */ 2750 BUG_ON(s->failed != 2); 2751 /* fall through */ 2752 case check_state_compute_result: 2753 sh->check_state = check_state_idle; 2754 2755 /* check that a write has not made the stripe insync */ 2756 if (test_bit(STRIPE_INSYNC, &sh->state)) 2757 break; 2758 2759 /* now write out any block on a failed drive, 2760 * or P or Q if they were recomputed 2761 */ 2762 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */ 2763 if (s->failed == 2) { 2764 dev = &sh->dev[r6s->failed_num[1]]; 2765 s->locked++; 2766 set_bit(R5_LOCKED, &dev->flags); 2767 set_bit(R5_Wantwrite, &dev->flags); 2768 } 2769 if (s->failed >= 1) { 2770 dev = &sh->dev[r6s->failed_num[0]]; 2771 s->locked++; 2772 set_bit(R5_LOCKED, &dev->flags); 2773 set_bit(R5_Wantwrite, &dev->flags); 2774 } 2775 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) { 2776 dev = &sh->dev[pd_idx]; 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_Q_RESULT) { 2782 dev = &sh->dev[qd_idx]; 2783 s->locked++; 2784 set_bit(R5_LOCKED, &dev->flags); 2785 set_bit(R5_Wantwrite, &dev->flags); 2786 } 2787 clear_bit(STRIPE_DEGRADED, &sh->state); 2788 2789 set_bit(STRIPE_INSYNC, &sh->state); 2790 break; 2791 case check_state_run: 2792 case check_state_run_q: 2793 case check_state_run_pq: 2794 break; /* we will be called again upon completion */ 2795 case check_state_check_result: 2796 sh->check_state = check_state_idle; 2797 2798 /* handle a successful check operation, if parity is correct 2799 * we are done. Otherwise update the mismatch count and repair 2800 * parity if !MD_RECOVERY_CHECK 2801 */ 2802 if (sh->ops.zero_sum_result == 0) { 2803 /* both parities are correct */ 2804 if (!s->failed) 2805 set_bit(STRIPE_INSYNC, &sh->state); 2806 else { 2807 /* in contrast to the raid5 case we can validate 2808 * parity, but still have a failure to write 2809 * back 2810 */ 2811 sh->check_state = check_state_compute_result; 2812 /* Returning at this point means that we may go 2813 * off and bring p and/or q uptodate again so 2814 * we make sure to check zero_sum_result again 2815 * to verify if p or q need writeback 2816 */ 2817 } 2818 } else { 2819 conf->mddev->resync_mismatches += STRIPE_SECTORS; 2820 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) 2821 /* don't try to repair!! */ 2822 set_bit(STRIPE_INSYNC, &sh->state); 2823 else { 2824 int *target = &sh->ops.target; 2825 2826 sh->ops.target = -1; 2827 sh->ops.target2 = -1; 2828 sh->check_state = check_state_compute_run; 2829 set_bit(STRIPE_COMPUTE_RUN, &sh->state); 2830 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); 2831 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) { 2832 set_bit(R5_Wantcompute, 2833 &sh->dev[pd_idx].flags); 2834 *target = pd_idx; 2835 target = &sh->ops.target2; 2836 s->uptodate++; 2837 } 2838 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) { 2839 set_bit(R5_Wantcompute, 2840 &sh->dev[qd_idx].flags); 2841 *target = qd_idx; 2842 s->uptodate++; 2843 } 2844 } 2845 } 2846 break; 2847 case check_state_compute_run: 2848 break; 2849 default: 2850 printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n", 2851 __func__, sh->check_state, 2852 (unsigned long long) sh->sector); 2853 BUG(); 2854 } 2855 } 2856 2857 static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, 2858 struct r6_state *r6s) 2859 { 2860 int i; 2861 2862 /* We have read all the blocks in this stripe and now we need to 2863 * copy some of them into a target stripe for expand. 2864 */ 2865 struct dma_async_tx_descriptor *tx = NULL; 2866 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2867 for (i = 0; i < sh->disks; i++) 2868 if (i != sh->pd_idx && i != sh->qd_idx) { 2869 int dd_idx, j; 2870 struct stripe_head *sh2; 2871 struct async_submit_ctl submit; 2872 2873 sector_t bn = compute_blocknr(sh, i, 1); 2874 sector_t s = raid5_compute_sector(conf, bn, 0, 2875 &dd_idx, NULL); 2876 sh2 = get_active_stripe(conf, s, 0, 1, 1); 2877 if (sh2 == NULL) 2878 /* so far only the early blocks of this stripe 2879 * have been requested. When later blocks 2880 * get requested, we will try again 2881 */ 2882 continue; 2883 if (!test_bit(STRIPE_EXPANDING, &sh2->state) || 2884 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) { 2885 /* must have already done this block */ 2886 release_stripe(sh2); 2887 continue; 2888 } 2889 2890 /* place all the copies on one channel */ 2891 init_async_submit(&submit, 0, tx, NULL, NULL, NULL); 2892 tx = async_memcpy(sh2->dev[dd_idx].page, 2893 sh->dev[i].page, 0, 0, STRIPE_SIZE, 2894 &submit); 2895 2896 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags); 2897 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags); 2898 for (j = 0; j < conf->raid_disks; j++) 2899 if (j != sh2->pd_idx && 2900 (!r6s || j != sh2->qd_idx) && 2901 !test_bit(R5_Expanded, &sh2->dev[j].flags)) 2902 break; 2903 if (j == conf->raid_disks) { 2904 set_bit(STRIPE_EXPAND_READY, &sh2->state); 2905 set_bit(STRIPE_HANDLE, &sh2->state); 2906 } 2907 release_stripe(sh2); 2908 2909 } 2910 /* done submitting copies, wait for them to complete */ 2911 if (tx) { 2912 async_tx_ack(tx); 2913 dma_wait_for_async_tx(tx); 2914 } 2915 } 2916 2917 2918 /* 2919 * handle_stripe - do things to a stripe. 2920 * 2921 * We lock the stripe and then examine the state of various bits 2922 * to see what needs to be done. 2923 * Possible results: 2924 * return some read request which now have data 2925 * return some write requests which are safely on disc 2926 * schedule a read on some buffers 2927 * schedule a write of some buffers 2928 * return confirmation of parity correctness 2929 * 2930 * buffers are taken off read_list or write_list, and bh_cache buffers 2931 * get BH_Lock set before the stripe lock is released. 2932 * 2933 */ 2934 2935 static void handle_stripe5(struct stripe_head *sh) 2936 { 2937 raid5_conf_t *conf = sh->raid_conf; 2938 int disks = sh->disks, i; 2939 struct bio *return_bi = NULL; 2940 struct stripe_head_state s; 2941 struct r5dev *dev; 2942 mdk_rdev_t *blocked_rdev = NULL; 2943 int prexor; 2944 int dec_preread_active = 0; 2945 2946 memset(&s, 0, sizeof(s)); 2947 pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d " 2948 "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state, 2949 atomic_read(&sh->count), sh->pd_idx, sh->check_state, 2950 sh->reconstruct_state); 2951 2952 spin_lock(&sh->lock); 2953 clear_bit(STRIPE_HANDLE, &sh->state); 2954 clear_bit(STRIPE_DELAYED, &sh->state); 2955 2956 s.syncing = test_bit(STRIPE_SYNCING, &sh->state); 2957 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 2958 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 2959 2960 /* Now to look around and see what can be done */ 2961 rcu_read_lock(); 2962 for (i=disks; i--; ) { 2963 mdk_rdev_t *rdev; 2964 2965 dev = &sh->dev[i]; 2966 clear_bit(R5_Insync, &dev->flags); 2967 2968 pr_debug("check %d: state 0x%lx toread %p read %p write %p " 2969 "written %p\n", i, dev->flags, dev->toread, dev->read, 2970 dev->towrite, dev->written); 2971 2972 /* maybe we can request a biofill operation 2973 * 2974 * new wantfill requests are only permitted while 2975 * ops_complete_biofill is guaranteed to be inactive 2976 */ 2977 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && 2978 !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) 2979 set_bit(R5_Wantfill, &dev->flags); 2980 2981 /* now count some things */ 2982 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; 2983 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; 2984 if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++; 2985 2986 if (test_bit(R5_Wantfill, &dev->flags)) 2987 s.to_fill++; 2988 else if (dev->toread) 2989 s.to_read++; 2990 if (dev->towrite) { 2991 s.to_write++; 2992 if (!test_bit(R5_OVERWRITE, &dev->flags)) 2993 s.non_overwrite++; 2994 } 2995 if (dev->written) 2996 s.written++; 2997 rdev = rcu_dereference(conf->disks[i].rdev); 2998 if (blocked_rdev == NULL && 2999 rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 3000 blocked_rdev = rdev; 3001 atomic_inc(&rdev->nr_pending); 3002 } 3003 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 3004 /* The ReadError flag will just be confusing now */ 3005 clear_bit(R5_ReadError, &dev->flags); 3006 clear_bit(R5_ReWrite, &dev->flags); 3007 } 3008 if (!rdev || !test_bit(In_sync, &rdev->flags) 3009 || test_bit(R5_ReadError, &dev->flags)) { 3010 s.failed++; 3011 s.failed_num = i; 3012 } else 3013 set_bit(R5_Insync, &dev->flags); 3014 } 3015 rcu_read_unlock(); 3016 3017 if (unlikely(blocked_rdev)) { 3018 if (s.syncing || s.expanding || s.expanded || 3019 s.to_write || s.written) { 3020 set_bit(STRIPE_HANDLE, &sh->state); 3021 goto unlock; 3022 } 3023 /* There is nothing for the blocked_rdev to block */ 3024 rdev_dec_pending(blocked_rdev, conf->mddev); 3025 blocked_rdev = NULL; 3026 } 3027 3028 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) { 3029 set_bit(STRIPE_OP_BIOFILL, &s.ops_request); 3030 set_bit(STRIPE_BIOFILL_RUN, &sh->state); 3031 } 3032 3033 pr_debug("locked=%d uptodate=%d to_read=%d" 3034 " to_write=%d failed=%d failed_num=%d\n", 3035 s.locked, s.uptodate, s.to_read, s.to_write, 3036 s.failed, s.failed_num); 3037 /* check if the array has lost two devices and, if so, some requests might 3038 * need to be failed 3039 */ 3040 if (s.failed > 1 && s.to_read+s.to_write+s.written) 3041 handle_failed_stripe(conf, sh, &s, disks, &return_bi); 3042 if (s.failed > 1 && s.syncing) { 3043 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 3044 clear_bit(STRIPE_SYNCING, &sh->state); 3045 s.syncing = 0; 3046 } 3047 3048 /* might be able to return some write requests if the parity block 3049 * is safe, or on a failed drive 3050 */ 3051 dev = &sh->dev[sh->pd_idx]; 3052 if ( s.written && 3053 ((test_bit(R5_Insync, &dev->flags) && 3054 !test_bit(R5_LOCKED, &dev->flags) && 3055 test_bit(R5_UPTODATE, &dev->flags)) || 3056 (s.failed == 1 && s.failed_num == sh->pd_idx))) 3057 handle_stripe_clean_event(conf, sh, disks, &return_bi); 3058 3059 /* Now we might consider reading some blocks, either to check/generate 3060 * parity, or to satisfy requests 3061 * or to load a block that is being partially written. 3062 */ 3063 if (s.to_read || s.non_overwrite || 3064 (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding) 3065 handle_stripe_fill5(sh, &s, disks); 3066 3067 /* Now we check to see if any write operations have recently 3068 * completed 3069 */ 3070 prexor = 0; 3071 if (sh->reconstruct_state == reconstruct_state_prexor_drain_result) 3072 prexor = 1; 3073 if (sh->reconstruct_state == reconstruct_state_drain_result || 3074 sh->reconstruct_state == reconstruct_state_prexor_drain_result) { 3075 sh->reconstruct_state = reconstruct_state_idle; 3076 3077 /* All the 'written' buffers and the parity block are ready to 3078 * be written back to disk 3079 */ 3080 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); 3081 for (i = disks; i--; ) { 3082 dev = &sh->dev[i]; 3083 if (test_bit(R5_LOCKED, &dev->flags) && 3084 (i == sh->pd_idx || dev->written)) { 3085 pr_debug("Writing block %d\n", i); 3086 set_bit(R5_Wantwrite, &dev->flags); 3087 if (prexor) 3088 continue; 3089 if (!test_bit(R5_Insync, &dev->flags) || 3090 (i == sh->pd_idx && s.failed == 0)) 3091 set_bit(STRIPE_INSYNC, &sh->state); 3092 } 3093 } 3094 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 3095 dec_preread_active = 1; 3096 } 3097 3098 /* Now to consider new write requests and what else, if anything 3099 * should be read. We do not handle new writes when: 3100 * 1/ A 'write' operation (copy+xor) is already in flight. 3101 * 2/ A 'check' operation is in flight, as it may clobber the parity 3102 * block. 3103 */ 3104 if (s.to_write && !sh->reconstruct_state && !sh->check_state) 3105 handle_stripe_dirtying5(conf, sh, &s, disks); 3106 3107 /* maybe we need to check and possibly fix the parity for this stripe 3108 * Any reads will already have been scheduled, so we just see if enough 3109 * data is available. The parity check is held off while parity 3110 * dependent operations are in flight. 3111 */ 3112 if (sh->check_state || 3113 (s.syncing && s.locked == 0 && 3114 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) && 3115 !test_bit(STRIPE_INSYNC, &sh->state))) 3116 handle_parity_checks5(conf, sh, &s, disks); 3117 3118 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 3119 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 3120 clear_bit(STRIPE_SYNCING, &sh->state); 3121 } 3122 3123 /* If the failed drive is just a ReadError, then we might need to progress 3124 * the repair/check process 3125 */ 3126 if (s.failed == 1 && !conf->mddev->ro && 3127 test_bit(R5_ReadError, &sh->dev[s.failed_num].flags) 3128 && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags) 3129 && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags) 3130 ) { 3131 dev = &sh->dev[s.failed_num]; 3132 if (!test_bit(R5_ReWrite, &dev->flags)) { 3133 set_bit(R5_Wantwrite, &dev->flags); 3134 set_bit(R5_ReWrite, &dev->flags); 3135 set_bit(R5_LOCKED, &dev->flags); 3136 s.locked++; 3137 } else { 3138 /* let's read it back */ 3139 set_bit(R5_Wantread, &dev->flags); 3140 set_bit(R5_LOCKED, &dev->flags); 3141 s.locked++; 3142 } 3143 } 3144 3145 /* Finish reconstruct operations initiated by the expansion process */ 3146 if (sh->reconstruct_state == reconstruct_state_result) { 3147 struct stripe_head *sh2 3148 = get_active_stripe(conf, sh->sector, 1, 1, 1); 3149 if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) { 3150 /* sh cannot be written until sh2 has been read. 3151 * so arrange for sh to be delayed a little 3152 */ 3153 set_bit(STRIPE_DELAYED, &sh->state); 3154 set_bit(STRIPE_HANDLE, &sh->state); 3155 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, 3156 &sh2->state)) 3157 atomic_inc(&conf->preread_active_stripes); 3158 release_stripe(sh2); 3159 goto unlock; 3160 } 3161 if (sh2) 3162 release_stripe(sh2); 3163 3164 sh->reconstruct_state = reconstruct_state_idle; 3165 clear_bit(STRIPE_EXPANDING, &sh->state); 3166 for (i = conf->raid_disks; i--; ) { 3167 set_bit(R5_Wantwrite, &sh->dev[i].flags); 3168 set_bit(R5_LOCKED, &sh->dev[i].flags); 3169 s.locked++; 3170 } 3171 } 3172 3173 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) && 3174 !sh->reconstruct_state) { 3175 /* Need to write out all blocks after computing parity */ 3176 sh->disks = conf->raid_disks; 3177 stripe_set_idx(sh->sector, conf, 0, sh); 3178 schedule_reconstruction(sh, &s, 1, 1); 3179 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) { 3180 clear_bit(STRIPE_EXPAND_READY, &sh->state); 3181 atomic_dec(&conf->reshape_stripes); 3182 wake_up(&conf->wait_for_overlap); 3183 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 3184 } 3185 3186 if (s.expanding && s.locked == 0 && 3187 !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) 3188 handle_stripe_expansion(conf, sh, NULL); 3189 3190 unlock: 3191 spin_unlock(&sh->lock); 3192 3193 /* wait for this device to become unblocked */ 3194 if (unlikely(blocked_rdev)) 3195 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); 3196 3197 if (s.ops_request) 3198 raid_run_ops(sh, s.ops_request); 3199 3200 ops_run_io(sh, &s); 3201 3202 if (dec_preread_active) { 3203 /* We delay this until after ops_run_io so that if make_request 3204 * is waiting on a barrier, it won't continue until the writes 3205 * have actually been submitted. 3206 */ 3207 atomic_dec(&conf->preread_active_stripes); 3208 if (atomic_read(&conf->preread_active_stripes) < 3209 IO_THRESHOLD) 3210 md_wakeup_thread(conf->mddev->thread); 3211 } 3212 return_io(return_bi); 3213 } 3214 3215 static void handle_stripe6(struct stripe_head *sh) 3216 { 3217 raid5_conf_t *conf = sh->raid_conf; 3218 int disks = sh->disks; 3219 struct bio *return_bi = NULL; 3220 int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx; 3221 struct stripe_head_state s; 3222 struct r6_state r6s; 3223 struct r5dev *dev, *pdev, *qdev; 3224 mdk_rdev_t *blocked_rdev = NULL; 3225 int dec_preread_active = 0; 3226 3227 pr_debug("handling stripe %llu, state=%#lx cnt=%d, " 3228 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n", 3229 (unsigned long long)sh->sector, sh->state, 3230 atomic_read(&sh->count), pd_idx, qd_idx, 3231 sh->check_state, sh->reconstruct_state); 3232 memset(&s, 0, sizeof(s)); 3233 3234 spin_lock(&sh->lock); 3235 clear_bit(STRIPE_HANDLE, &sh->state); 3236 clear_bit(STRIPE_DELAYED, &sh->state); 3237 3238 s.syncing = test_bit(STRIPE_SYNCING, &sh->state); 3239 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); 3240 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); 3241 /* Now to look around and see what can be done */ 3242 3243 rcu_read_lock(); 3244 for (i=disks; i--; ) { 3245 mdk_rdev_t *rdev; 3246 dev = &sh->dev[i]; 3247 clear_bit(R5_Insync, &dev->flags); 3248 3249 pr_debug("check %d: state 0x%lx read %p write %p written %p\n", 3250 i, dev->flags, dev->toread, dev->towrite, dev->written); 3251 /* maybe we can reply to a read 3252 * 3253 * new wantfill requests are only permitted while 3254 * ops_complete_biofill is guaranteed to be inactive 3255 */ 3256 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && 3257 !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) 3258 set_bit(R5_Wantfill, &dev->flags); 3259 3260 /* now count some things */ 3261 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; 3262 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; 3263 if (test_bit(R5_Wantcompute, &dev->flags)) { 3264 s.compute++; 3265 BUG_ON(s.compute > 2); 3266 } 3267 3268 if (test_bit(R5_Wantfill, &dev->flags)) { 3269 s.to_fill++; 3270 } else if (dev->toread) 3271 s.to_read++; 3272 if (dev->towrite) { 3273 s.to_write++; 3274 if (!test_bit(R5_OVERWRITE, &dev->flags)) 3275 s.non_overwrite++; 3276 } 3277 if (dev->written) 3278 s.written++; 3279 rdev = rcu_dereference(conf->disks[i].rdev); 3280 if (blocked_rdev == NULL && 3281 rdev && unlikely(test_bit(Blocked, &rdev->flags))) { 3282 blocked_rdev = rdev; 3283 atomic_inc(&rdev->nr_pending); 3284 } 3285 if (!rdev || !test_bit(In_sync, &rdev->flags)) { 3286 /* The ReadError flag will just be confusing now */ 3287 clear_bit(R5_ReadError, &dev->flags); 3288 clear_bit(R5_ReWrite, &dev->flags); 3289 } 3290 if (!rdev || !test_bit(In_sync, &rdev->flags) 3291 || test_bit(R5_ReadError, &dev->flags)) { 3292 if (s.failed < 2) 3293 r6s.failed_num[s.failed] = i; 3294 s.failed++; 3295 } else 3296 set_bit(R5_Insync, &dev->flags); 3297 } 3298 rcu_read_unlock(); 3299 3300 if (unlikely(blocked_rdev)) { 3301 if (s.syncing || s.expanding || s.expanded || 3302 s.to_write || s.written) { 3303 set_bit(STRIPE_HANDLE, &sh->state); 3304 goto unlock; 3305 } 3306 /* There is nothing for the blocked_rdev to block */ 3307 rdev_dec_pending(blocked_rdev, conf->mddev); 3308 blocked_rdev = NULL; 3309 } 3310 3311 if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) { 3312 set_bit(STRIPE_OP_BIOFILL, &s.ops_request); 3313 set_bit(STRIPE_BIOFILL_RUN, &sh->state); 3314 } 3315 3316 pr_debug("locked=%d uptodate=%d to_read=%d" 3317 " to_write=%d failed=%d failed_num=%d,%d\n", 3318 s.locked, s.uptodate, s.to_read, s.to_write, s.failed, 3319 r6s.failed_num[0], r6s.failed_num[1]); 3320 /* check if the array has lost >2 devices and, if so, some requests 3321 * might need to be failed 3322 */ 3323 if (s.failed > 2 && s.to_read+s.to_write+s.written) 3324 handle_failed_stripe(conf, sh, &s, disks, &return_bi); 3325 if (s.failed > 2 && s.syncing) { 3326 md_done_sync(conf->mddev, STRIPE_SECTORS,0); 3327 clear_bit(STRIPE_SYNCING, &sh->state); 3328 s.syncing = 0; 3329 } 3330 3331 /* 3332 * might be able to return some write requests if the parity blocks 3333 * are safe, or on a failed drive 3334 */ 3335 pdev = &sh->dev[pd_idx]; 3336 r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx) 3337 || (s.failed >= 2 && r6s.failed_num[1] == pd_idx); 3338 qdev = &sh->dev[qd_idx]; 3339 r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == qd_idx) 3340 || (s.failed >= 2 && r6s.failed_num[1] == qd_idx); 3341 3342 if ( s.written && 3343 ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags) 3344 && !test_bit(R5_LOCKED, &pdev->flags) 3345 && test_bit(R5_UPTODATE, &pdev->flags)))) && 3346 ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags) 3347 && !test_bit(R5_LOCKED, &qdev->flags) 3348 && test_bit(R5_UPTODATE, &qdev->flags))))) 3349 handle_stripe_clean_event(conf, sh, disks, &return_bi); 3350 3351 /* Now we might consider reading some blocks, either to check/generate 3352 * parity, or to satisfy requests 3353 * or to load a block that is being partially written. 3354 */ 3355 if (s.to_read || s.non_overwrite || (s.to_write && s.failed) || 3356 (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding) 3357 handle_stripe_fill6(sh, &s, &r6s, disks); 3358 3359 /* Now we check to see if any write operations have recently 3360 * completed 3361 */ 3362 if (sh->reconstruct_state == reconstruct_state_drain_result) { 3363 3364 sh->reconstruct_state = reconstruct_state_idle; 3365 /* All the 'written' buffers and the parity blocks are ready to 3366 * be written back to disk 3367 */ 3368 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); 3369 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags)); 3370 for (i = disks; i--; ) { 3371 dev = &sh->dev[i]; 3372 if (test_bit(R5_LOCKED, &dev->flags) && 3373 (i == sh->pd_idx || i == qd_idx || 3374 dev->written)) { 3375 pr_debug("Writing block %d\n", i); 3376 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); 3377 set_bit(R5_Wantwrite, &dev->flags); 3378 if (!test_bit(R5_Insync, &dev->flags) || 3379 ((i == sh->pd_idx || i == qd_idx) && 3380 s.failed == 0)) 3381 set_bit(STRIPE_INSYNC, &sh->state); 3382 } 3383 } 3384 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 3385 dec_preread_active = 1; 3386 } 3387 3388 /* Now to consider new write requests and what else, if anything 3389 * should be read. We do not handle new writes when: 3390 * 1/ A 'write' operation (copy+gen_syndrome) is already in flight. 3391 * 2/ A 'check' operation is in flight, as it may clobber the parity 3392 * block. 3393 */ 3394 if (s.to_write && !sh->reconstruct_state && !sh->check_state) 3395 handle_stripe_dirtying6(conf, sh, &s, &r6s, disks); 3396 3397 /* maybe we need to check and possibly fix the parity for this stripe 3398 * Any reads will already have been scheduled, so we just see if enough 3399 * data is available. The parity check is held off while parity 3400 * dependent operations are in flight. 3401 */ 3402 if (sh->check_state || 3403 (s.syncing && s.locked == 0 && 3404 !test_bit(STRIPE_COMPUTE_RUN, &sh->state) && 3405 !test_bit(STRIPE_INSYNC, &sh->state))) 3406 handle_parity_checks6(conf, sh, &s, &r6s, disks); 3407 3408 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { 3409 md_done_sync(conf->mddev, STRIPE_SECTORS,1); 3410 clear_bit(STRIPE_SYNCING, &sh->state); 3411 } 3412 3413 /* If the failed drives are just a ReadError, then we might need 3414 * to progress the repair/check process 3415 */ 3416 if (s.failed <= 2 && !conf->mddev->ro) 3417 for (i = 0; i < s.failed; i++) { 3418 dev = &sh->dev[r6s.failed_num[i]]; 3419 if (test_bit(R5_ReadError, &dev->flags) 3420 && !test_bit(R5_LOCKED, &dev->flags) 3421 && test_bit(R5_UPTODATE, &dev->flags) 3422 ) { 3423 if (!test_bit(R5_ReWrite, &dev->flags)) { 3424 set_bit(R5_Wantwrite, &dev->flags); 3425 set_bit(R5_ReWrite, &dev->flags); 3426 set_bit(R5_LOCKED, &dev->flags); 3427 s.locked++; 3428 } else { 3429 /* let's read it back */ 3430 set_bit(R5_Wantread, &dev->flags); 3431 set_bit(R5_LOCKED, &dev->flags); 3432 s.locked++; 3433 } 3434 } 3435 } 3436 3437 /* Finish reconstruct operations initiated by the expansion process */ 3438 if (sh->reconstruct_state == reconstruct_state_result) { 3439 sh->reconstruct_state = reconstruct_state_idle; 3440 clear_bit(STRIPE_EXPANDING, &sh->state); 3441 for (i = conf->raid_disks; i--; ) { 3442 set_bit(R5_Wantwrite, &sh->dev[i].flags); 3443 set_bit(R5_LOCKED, &sh->dev[i].flags); 3444 s.locked++; 3445 } 3446 } 3447 3448 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) && 3449 !sh->reconstruct_state) { 3450 struct stripe_head *sh2 3451 = get_active_stripe(conf, sh->sector, 1, 1, 1); 3452 if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) { 3453 /* sh cannot be written until sh2 has been read. 3454 * so arrange for sh to be delayed a little 3455 */ 3456 set_bit(STRIPE_DELAYED, &sh->state); 3457 set_bit(STRIPE_HANDLE, &sh->state); 3458 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, 3459 &sh2->state)) 3460 atomic_inc(&conf->preread_active_stripes); 3461 release_stripe(sh2); 3462 goto unlock; 3463 } 3464 if (sh2) 3465 release_stripe(sh2); 3466 3467 /* Need to write out all blocks after computing P&Q */ 3468 sh->disks = conf->raid_disks; 3469 stripe_set_idx(sh->sector, conf, 0, sh); 3470 schedule_reconstruction(sh, &s, 1, 1); 3471 } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) { 3472 clear_bit(STRIPE_EXPAND_READY, &sh->state); 3473 atomic_dec(&conf->reshape_stripes); 3474 wake_up(&conf->wait_for_overlap); 3475 md_done_sync(conf->mddev, STRIPE_SECTORS, 1); 3476 } 3477 3478 if (s.expanding && s.locked == 0 && 3479 !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) 3480 handle_stripe_expansion(conf, sh, &r6s); 3481 3482 unlock: 3483 spin_unlock(&sh->lock); 3484 3485 /* wait for this device to become unblocked */ 3486 if (unlikely(blocked_rdev)) 3487 md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); 3488 3489 if (s.ops_request) 3490 raid_run_ops(sh, s.ops_request); 3491 3492 ops_run_io(sh, &s); 3493 3494 3495 if (dec_preread_active) { 3496 /* We delay this until after ops_run_io so that if make_request 3497 * is waiting on a barrier, it won't continue until the writes 3498 * have actually been submitted. 3499 */ 3500 atomic_dec(&conf->preread_active_stripes); 3501 if (atomic_read(&conf->preread_active_stripes) < 3502 IO_THRESHOLD) 3503 md_wakeup_thread(conf->mddev->thread); 3504 } 3505 3506 return_io(return_bi); 3507 } 3508 3509 static void handle_stripe(struct stripe_head *sh) 3510 { 3511 if (sh->raid_conf->level == 6) 3512 handle_stripe6(sh); 3513 else 3514 handle_stripe5(sh); 3515 } 3516 3517 static void raid5_activate_delayed(raid5_conf_t *conf) 3518 { 3519 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { 3520 while (!list_empty(&conf->delayed_list)) { 3521 struct list_head *l = conf->delayed_list.next; 3522 struct stripe_head *sh; 3523 sh = list_entry(l, struct stripe_head, lru); 3524 list_del_init(l); 3525 clear_bit(STRIPE_DELAYED, &sh->state); 3526 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 3527 atomic_inc(&conf->preread_active_stripes); 3528 list_add_tail(&sh->lru, &conf->hold_list); 3529 } 3530 } else 3531 blk_plug_device(conf->mddev->queue); 3532 } 3533 3534 static void activate_bit_delay(raid5_conf_t *conf) 3535 { 3536 /* device_lock is held */ 3537 struct list_head head; 3538 list_add(&head, &conf->bitmap_list); 3539 list_del_init(&conf->bitmap_list); 3540 while (!list_empty(&head)) { 3541 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); 3542 list_del_init(&sh->lru); 3543 atomic_inc(&sh->count); 3544 __release_stripe(conf, sh); 3545 } 3546 } 3547 3548 static void unplug_slaves(mddev_t *mddev) 3549 { 3550 raid5_conf_t *conf = mddev->private; 3551 int i; 3552 int devs = max(conf->raid_disks, conf->previous_raid_disks); 3553 3554 rcu_read_lock(); 3555 for (i = 0; i < devs; i++) { 3556 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); 3557 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { 3558 struct request_queue *r_queue = bdev_get_queue(rdev->bdev); 3559 3560 atomic_inc(&rdev->nr_pending); 3561 rcu_read_unlock(); 3562 3563 blk_unplug(r_queue); 3564 3565 rdev_dec_pending(rdev, mddev); 3566 rcu_read_lock(); 3567 } 3568 } 3569 rcu_read_unlock(); 3570 } 3571 3572 static void raid5_unplug_device(struct request_queue *q) 3573 { 3574 mddev_t *mddev = q->queuedata; 3575 raid5_conf_t *conf = mddev->private; 3576 unsigned long flags; 3577 3578 spin_lock_irqsave(&conf->device_lock, flags); 3579 3580 if (blk_remove_plug(q)) { 3581 conf->seq_flush++; 3582 raid5_activate_delayed(conf); 3583 } 3584 md_wakeup_thread(mddev->thread); 3585 3586 spin_unlock_irqrestore(&conf->device_lock, flags); 3587 3588 unplug_slaves(mddev); 3589 } 3590 3591 static int raid5_congested(void *data, int bits) 3592 { 3593 mddev_t *mddev = data; 3594 raid5_conf_t *conf = mddev->private; 3595 3596 /* No difference between reads and writes. Just check 3597 * how busy the stripe_cache is 3598 */ 3599 3600 if (mddev_congested(mddev, bits)) 3601 return 1; 3602 if (conf->inactive_blocked) 3603 return 1; 3604 if (conf->quiesce) 3605 return 1; 3606 if (list_empty_careful(&conf->inactive_list)) 3607 return 1; 3608 3609 return 0; 3610 } 3611 3612 /* We want read requests to align with chunks where possible, 3613 * but write requests don't need to. 3614 */ 3615 static int raid5_mergeable_bvec(struct request_queue *q, 3616 struct bvec_merge_data *bvm, 3617 struct bio_vec *biovec) 3618 { 3619 mddev_t *mddev = q->queuedata; 3620 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); 3621 int max; 3622 unsigned int chunk_sectors = mddev->chunk_sectors; 3623 unsigned int bio_sectors = bvm->bi_size >> 9; 3624 3625 if ((bvm->bi_rw & 1) == WRITE) 3626 return biovec->bv_len; /* always allow writes to be mergeable */ 3627 3628 if (mddev->new_chunk_sectors < mddev->chunk_sectors) 3629 chunk_sectors = mddev->new_chunk_sectors; 3630 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; 3631 if (max < 0) max = 0; 3632 if (max <= biovec->bv_len && bio_sectors == 0) 3633 return biovec->bv_len; 3634 else 3635 return max; 3636 } 3637 3638 3639 static int in_chunk_boundary(mddev_t *mddev, struct bio *bio) 3640 { 3641 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); 3642 unsigned int chunk_sectors = mddev->chunk_sectors; 3643 unsigned int bio_sectors = bio->bi_size >> 9; 3644 3645 if (mddev->new_chunk_sectors < mddev->chunk_sectors) 3646 chunk_sectors = mddev->new_chunk_sectors; 3647 return chunk_sectors >= 3648 ((sector & (chunk_sectors - 1)) + bio_sectors); 3649 } 3650 3651 /* 3652 * add bio to the retry LIFO ( in O(1) ... we are in interrupt ) 3653 * later sampled by raid5d. 3654 */ 3655 static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf) 3656 { 3657 unsigned long flags; 3658 3659 spin_lock_irqsave(&conf->device_lock, flags); 3660 3661 bi->bi_next = conf->retry_read_aligned_list; 3662 conf->retry_read_aligned_list = bi; 3663 3664 spin_unlock_irqrestore(&conf->device_lock, flags); 3665 md_wakeup_thread(conf->mddev->thread); 3666 } 3667 3668 3669 static struct bio *remove_bio_from_retry(raid5_conf_t *conf) 3670 { 3671 struct bio *bi; 3672 3673 bi = conf->retry_read_aligned; 3674 if (bi) { 3675 conf->retry_read_aligned = NULL; 3676 return bi; 3677 } 3678 bi = conf->retry_read_aligned_list; 3679 if(bi) { 3680 conf->retry_read_aligned_list = bi->bi_next; 3681 bi->bi_next = NULL; 3682 /* 3683 * this sets the active strip count to 1 and the processed 3684 * strip count to zero (upper 8 bits) 3685 */ 3686 bi->bi_phys_segments = 1; /* biased count of active stripes */ 3687 } 3688 3689 return bi; 3690 } 3691 3692 3693 /* 3694 * The "raid5_align_endio" should check if the read succeeded and if it 3695 * did, call bio_endio on the original bio (having bio_put the new bio 3696 * first). 3697 * If the read failed.. 3698 */ 3699 static void raid5_align_endio(struct bio *bi, int error) 3700 { 3701 struct bio* raid_bi = bi->bi_private; 3702 mddev_t *mddev; 3703 raid5_conf_t *conf; 3704 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); 3705 mdk_rdev_t *rdev; 3706 3707 bio_put(bi); 3708 3709 rdev = (void*)raid_bi->bi_next; 3710 raid_bi->bi_next = NULL; 3711 mddev = rdev->mddev; 3712 conf = mddev->private; 3713 3714 rdev_dec_pending(rdev, conf->mddev); 3715 3716 if (!error && uptodate) { 3717 bio_endio(raid_bi, 0); 3718 if (atomic_dec_and_test(&conf->active_aligned_reads)) 3719 wake_up(&conf->wait_for_stripe); 3720 return; 3721 } 3722 3723 3724 pr_debug("raid5_align_endio : io error...handing IO for a retry\n"); 3725 3726 add_bio_to_retry(raid_bi, conf); 3727 } 3728 3729 static int bio_fits_rdev(struct bio *bi) 3730 { 3731 struct request_queue *q = bdev_get_queue(bi->bi_bdev); 3732 3733 if ((bi->bi_size>>9) > queue_max_sectors(q)) 3734 return 0; 3735 blk_recount_segments(q, bi); 3736 if (bi->bi_phys_segments > queue_max_segments(q)) 3737 return 0; 3738 3739 if (q->merge_bvec_fn) 3740 /* it's too hard to apply the merge_bvec_fn at this stage, 3741 * just just give up 3742 */ 3743 return 0; 3744 3745 return 1; 3746 } 3747 3748 3749 static int chunk_aligned_read(mddev_t *mddev, struct bio * raid_bio) 3750 { 3751 raid5_conf_t *conf = mddev->private; 3752 int dd_idx; 3753 struct bio* align_bi; 3754 mdk_rdev_t *rdev; 3755 3756 if (!in_chunk_boundary(mddev, raid_bio)) { 3757 pr_debug("chunk_aligned_read : non aligned\n"); 3758 return 0; 3759 } 3760 /* 3761 * use bio_clone to make a copy of the bio 3762 */ 3763 align_bi = bio_clone(raid_bio, GFP_NOIO); 3764 if (!align_bi) 3765 return 0; 3766 /* 3767 * set bi_end_io to a new function, and set bi_private to the 3768 * original bio. 3769 */ 3770 align_bi->bi_end_io = raid5_align_endio; 3771 align_bi->bi_private = raid_bio; 3772 /* 3773 * compute position 3774 */ 3775 align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector, 3776 0, 3777 &dd_idx, NULL); 3778 3779 rcu_read_lock(); 3780 rdev = rcu_dereference(conf->disks[dd_idx].rdev); 3781 if (rdev && test_bit(In_sync, &rdev->flags)) { 3782 atomic_inc(&rdev->nr_pending); 3783 rcu_read_unlock(); 3784 raid_bio->bi_next = (void*)rdev; 3785 align_bi->bi_bdev = rdev->bdev; 3786 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID); 3787 align_bi->bi_sector += rdev->data_offset; 3788 3789 if (!bio_fits_rdev(align_bi)) { 3790 /* too big in some way */ 3791 bio_put(align_bi); 3792 rdev_dec_pending(rdev, mddev); 3793 return 0; 3794 } 3795 3796 spin_lock_irq(&conf->device_lock); 3797 wait_event_lock_irq(conf->wait_for_stripe, 3798 conf->quiesce == 0, 3799 conf->device_lock, /* nothing */); 3800 atomic_inc(&conf->active_aligned_reads); 3801 spin_unlock_irq(&conf->device_lock); 3802 3803 generic_make_request(align_bi); 3804 return 1; 3805 } else { 3806 rcu_read_unlock(); 3807 bio_put(align_bi); 3808 return 0; 3809 } 3810 } 3811 3812 /* __get_priority_stripe - get the next stripe to process 3813 * 3814 * Full stripe writes are allowed to pass preread active stripes up until 3815 * the bypass_threshold is exceeded. In general the bypass_count 3816 * increments when the handle_list is handled before the hold_list; however, it 3817 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a 3818 * stripe with in flight i/o. The bypass_count will be reset when the 3819 * head of the hold_list has changed, i.e. the head was promoted to the 3820 * handle_list. 3821 */ 3822 static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf) 3823 { 3824 struct stripe_head *sh; 3825 3826 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n", 3827 __func__, 3828 list_empty(&conf->handle_list) ? "empty" : "busy", 3829 list_empty(&conf->hold_list) ? "empty" : "busy", 3830 atomic_read(&conf->pending_full_writes), conf->bypass_count); 3831 3832 if (!list_empty(&conf->handle_list)) { 3833 sh = list_entry(conf->handle_list.next, typeof(*sh), lru); 3834 3835 if (list_empty(&conf->hold_list)) 3836 conf->bypass_count = 0; 3837 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) { 3838 if (conf->hold_list.next == conf->last_hold) 3839 conf->bypass_count++; 3840 else { 3841 conf->last_hold = conf->hold_list.next; 3842 conf->bypass_count -= conf->bypass_threshold; 3843 if (conf->bypass_count < 0) 3844 conf->bypass_count = 0; 3845 } 3846 } 3847 } else if (!list_empty(&conf->hold_list) && 3848 ((conf->bypass_threshold && 3849 conf->bypass_count > conf->bypass_threshold) || 3850 atomic_read(&conf->pending_full_writes) == 0)) { 3851 sh = list_entry(conf->hold_list.next, 3852 typeof(*sh), lru); 3853 conf->bypass_count -= conf->bypass_threshold; 3854 if (conf->bypass_count < 0) 3855 conf->bypass_count = 0; 3856 } else 3857 return NULL; 3858 3859 list_del_init(&sh->lru); 3860 atomic_inc(&sh->count); 3861 BUG_ON(atomic_read(&sh->count) != 1); 3862 return sh; 3863 } 3864 3865 static int make_request(mddev_t *mddev, struct bio * bi) 3866 { 3867 raid5_conf_t *conf = mddev->private; 3868 int dd_idx; 3869 sector_t new_sector; 3870 sector_t logical_sector, last_sector; 3871 struct stripe_head *sh; 3872 const int rw = bio_data_dir(bi); 3873 int remaining; 3874 3875 if (unlikely(bio_rw_flagged(bi, BIO_RW_BARRIER))) { 3876 /* Drain all pending writes. We only really need 3877 * to ensure they have been submitted, but this is 3878 * easier. 3879 */ 3880 mddev->pers->quiesce(mddev, 1); 3881 mddev->pers->quiesce(mddev, 0); 3882 md_barrier_request(mddev, bi); 3883 return 0; 3884 } 3885 3886 md_write_start(mddev, bi); 3887 3888 if (rw == READ && 3889 mddev->reshape_position == MaxSector && 3890 chunk_aligned_read(mddev,bi)) 3891 return 0; 3892 3893 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 3894 last_sector = bi->bi_sector + (bi->bi_size>>9); 3895 bi->bi_next = NULL; 3896 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ 3897 3898 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { 3899 DEFINE_WAIT(w); 3900 int disks, data_disks; 3901 int previous; 3902 3903 retry: 3904 previous = 0; 3905 disks = conf->raid_disks; 3906 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); 3907 if (unlikely(conf->reshape_progress != MaxSector)) { 3908 /* spinlock is needed as reshape_progress may be 3909 * 64bit on a 32bit platform, and so it might be 3910 * possible to see a half-updated value 3911 * Ofcourse reshape_progress could change after 3912 * the lock is dropped, so once we get a reference 3913 * to the stripe that we think it is, we will have 3914 * to check again. 3915 */ 3916 spin_lock_irq(&conf->device_lock); 3917 if (mddev->delta_disks < 0 3918 ? logical_sector < conf->reshape_progress 3919 : logical_sector >= conf->reshape_progress) { 3920 disks = conf->previous_raid_disks; 3921 previous = 1; 3922 } else { 3923 if (mddev->delta_disks < 0 3924 ? logical_sector < conf->reshape_safe 3925 : logical_sector >= conf->reshape_safe) { 3926 spin_unlock_irq(&conf->device_lock); 3927 schedule(); 3928 goto retry; 3929 } 3930 } 3931 spin_unlock_irq(&conf->device_lock); 3932 } 3933 data_disks = disks - conf->max_degraded; 3934 3935 new_sector = raid5_compute_sector(conf, logical_sector, 3936 previous, 3937 &dd_idx, NULL); 3938 pr_debug("raid456: make_request, sector %llu logical %llu\n", 3939 (unsigned long long)new_sector, 3940 (unsigned long long)logical_sector); 3941 3942 sh = get_active_stripe(conf, new_sector, previous, 3943 (bi->bi_rw&RWA_MASK), 0); 3944 if (sh) { 3945 if (unlikely(previous)) { 3946 /* expansion might have moved on while waiting for a 3947 * stripe, so we must do the range check again. 3948 * Expansion could still move past after this 3949 * test, but as we are holding a reference to 3950 * 'sh', we know that if that happens, 3951 * STRIPE_EXPANDING will get set and the expansion 3952 * won't proceed until we finish with the stripe. 3953 */ 3954 int must_retry = 0; 3955 spin_lock_irq(&conf->device_lock); 3956 if (mddev->delta_disks < 0 3957 ? logical_sector >= conf->reshape_progress 3958 : logical_sector < conf->reshape_progress) 3959 /* mismatch, need to try again */ 3960 must_retry = 1; 3961 spin_unlock_irq(&conf->device_lock); 3962 if (must_retry) { 3963 release_stripe(sh); 3964 schedule(); 3965 goto retry; 3966 } 3967 } 3968 3969 if (bio_data_dir(bi) == WRITE && 3970 logical_sector >= mddev->suspend_lo && 3971 logical_sector < mddev->suspend_hi) { 3972 release_stripe(sh); 3973 /* As the suspend_* range is controlled by 3974 * userspace, we want an interruptible 3975 * wait. 3976 */ 3977 flush_signals(current); 3978 prepare_to_wait(&conf->wait_for_overlap, 3979 &w, TASK_INTERRUPTIBLE); 3980 if (logical_sector >= mddev->suspend_lo && 3981 logical_sector < mddev->suspend_hi) 3982 schedule(); 3983 goto retry; 3984 } 3985 3986 if (test_bit(STRIPE_EXPANDING, &sh->state) || 3987 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { 3988 /* Stripe is busy expanding or 3989 * add failed due to overlap. Flush everything 3990 * and wait a while 3991 */ 3992 raid5_unplug_device(mddev->queue); 3993 release_stripe(sh); 3994 schedule(); 3995 goto retry; 3996 } 3997 finish_wait(&conf->wait_for_overlap, &w); 3998 set_bit(STRIPE_HANDLE, &sh->state); 3999 clear_bit(STRIPE_DELAYED, &sh->state); 4000 if (mddev->barrier && 4001 !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) 4002 atomic_inc(&conf->preread_active_stripes); 4003 release_stripe(sh); 4004 } else { 4005 /* cannot get stripe for read-ahead, just give-up */ 4006 clear_bit(BIO_UPTODATE, &bi->bi_flags); 4007 finish_wait(&conf->wait_for_overlap, &w); 4008 break; 4009 } 4010 4011 } 4012 spin_lock_irq(&conf->device_lock); 4013 remaining = raid5_dec_bi_phys_segments(bi); 4014 spin_unlock_irq(&conf->device_lock); 4015 if (remaining == 0) { 4016 4017 if ( rw == WRITE ) 4018 md_write_end(mddev); 4019 4020 bio_endio(bi, 0); 4021 } 4022 4023 if (mddev->barrier) { 4024 /* We need to wait for the stripes to all be handled. 4025 * So: wait for preread_active_stripes to drop to 0. 4026 */ 4027 wait_event(mddev->thread->wqueue, 4028 atomic_read(&conf->preread_active_stripes) == 0); 4029 } 4030 return 0; 4031 } 4032 4033 static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks); 4034 4035 static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped) 4036 { 4037 /* reshaping is quite different to recovery/resync so it is 4038 * handled quite separately ... here. 4039 * 4040 * On each call to sync_request, we gather one chunk worth of 4041 * destination stripes and flag them as expanding. 4042 * Then we find all the source stripes and request reads. 4043 * As the reads complete, handle_stripe will copy the data 4044 * into the destination stripe and release that stripe. 4045 */ 4046 raid5_conf_t *conf = mddev->private; 4047 struct stripe_head *sh; 4048 sector_t first_sector, last_sector; 4049 int raid_disks = conf->previous_raid_disks; 4050 int data_disks = raid_disks - conf->max_degraded; 4051 int new_data_disks = conf->raid_disks - conf->max_degraded; 4052 int i; 4053 int dd_idx; 4054 sector_t writepos, readpos, safepos; 4055 sector_t stripe_addr; 4056 int reshape_sectors; 4057 struct list_head stripes; 4058 4059 if (sector_nr == 0) { 4060 /* If restarting in the middle, skip the initial sectors */ 4061 if (mddev->delta_disks < 0 && 4062 conf->reshape_progress < raid5_size(mddev, 0, 0)) { 4063 sector_nr = raid5_size(mddev, 0, 0) 4064 - conf->reshape_progress; 4065 } else if (mddev->delta_disks >= 0 && 4066 conf->reshape_progress > 0) 4067 sector_nr = conf->reshape_progress; 4068 sector_div(sector_nr, new_data_disks); 4069 if (sector_nr) { 4070 mddev->curr_resync_completed = sector_nr; 4071 sysfs_notify(&mddev->kobj, NULL, "sync_completed"); 4072 *skipped = 1; 4073 return sector_nr; 4074 } 4075 } 4076 4077 /* We need to process a full chunk at a time. 4078 * If old and new chunk sizes differ, we need to process the 4079 * largest of these 4080 */ 4081 if (mddev->new_chunk_sectors > mddev->chunk_sectors) 4082 reshape_sectors = mddev->new_chunk_sectors; 4083 else 4084 reshape_sectors = mddev->chunk_sectors; 4085 4086 /* we update the metadata when there is more than 3Meg 4087 * in the block range (that is rather arbitrary, should 4088 * probably be time based) or when the data about to be 4089 * copied would over-write the source of the data at 4090 * the front of the range. 4091 * i.e. one new_stripe along from reshape_progress new_maps 4092 * to after where reshape_safe old_maps to 4093 */ 4094 writepos = conf->reshape_progress; 4095 sector_div(writepos, new_data_disks); 4096 readpos = conf->reshape_progress; 4097 sector_div(readpos, data_disks); 4098 safepos = conf->reshape_safe; 4099 sector_div(safepos, data_disks); 4100 if (mddev->delta_disks < 0) { 4101 writepos -= min_t(sector_t, reshape_sectors, writepos); 4102 readpos += reshape_sectors; 4103 safepos += reshape_sectors; 4104 } else { 4105 writepos += reshape_sectors; 4106 readpos -= min_t(sector_t, reshape_sectors, readpos); 4107 safepos -= min_t(sector_t, reshape_sectors, safepos); 4108 } 4109 4110 /* 'writepos' is the most advanced device address we might write. 4111 * 'readpos' is the least advanced device address we might read. 4112 * 'safepos' is the least address recorded in the metadata as having 4113 * been reshaped. 4114 * If 'readpos' is behind 'writepos', then there is no way that we can 4115 * ensure safety in the face of a crash - that must be done by userspace 4116 * making a backup of the data. So in that case there is no particular 4117 * rush to update metadata. 4118 * Otherwise if 'safepos' is behind 'writepos', then we really need to 4119 * update the metadata to advance 'safepos' to match 'readpos' so that 4120 * we can be safe in the event of a crash. 4121 * So we insist on updating metadata if safepos is behind writepos and 4122 * readpos is beyond writepos. 4123 * In any case, update the metadata every 10 seconds. 4124 * Maybe that number should be configurable, but I'm not sure it is 4125 * worth it.... maybe it could be a multiple of safemode_delay??? 4126 */ 4127 if ((mddev->delta_disks < 0 4128 ? (safepos > writepos && readpos < writepos) 4129 : (safepos < writepos && readpos > writepos)) || 4130 time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) { 4131 /* Cannot proceed until we've updated the superblock... */ 4132 wait_event(conf->wait_for_overlap, 4133 atomic_read(&conf->reshape_stripes)==0); 4134 mddev->reshape_position = conf->reshape_progress; 4135 mddev->curr_resync_completed = mddev->curr_resync; 4136 conf->reshape_checkpoint = jiffies; 4137 set_bit(MD_CHANGE_DEVS, &mddev->flags); 4138 md_wakeup_thread(mddev->thread); 4139 wait_event(mddev->sb_wait, mddev->flags == 0 || 4140 kthread_should_stop()); 4141 spin_lock_irq(&conf->device_lock); 4142 conf->reshape_safe = mddev->reshape_position; 4143 spin_unlock_irq(&conf->device_lock); 4144 wake_up(&conf->wait_for_overlap); 4145 sysfs_notify(&mddev->kobj, NULL, "sync_completed"); 4146 } 4147 4148 if (mddev->delta_disks < 0) { 4149 BUG_ON(conf->reshape_progress == 0); 4150 stripe_addr = writepos; 4151 BUG_ON((mddev->dev_sectors & 4152 ~((sector_t)reshape_sectors - 1)) 4153 - reshape_sectors - stripe_addr 4154 != sector_nr); 4155 } else { 4156 BUG_ON(writepos != sector_nr + reshape_sectors); 4157 stripe_addr = sector_nr; 4158 } 4159 INIT_LIST_HEAD(&stripes); 4160 for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) { 4161 int j; 4162 int skipped_disk = 0; 4163 sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1); 4164 set_bit(STRIPE_EXPANDING, &sh->state); 4165 atomic_inc(&conf->reshape_stripes); 4166 /* If any of this stripe is beyond the end of the old 4167 * array, then we need to zero those blocks 4168 */ 4169 for (j=sh->disks; j--;) { 4170 sector_t s; 4171 if (j == sh->pd_idx) 4172 continue; 4173 if (conf->level == 6 && 4174 j == sh->qd_idx) 4175 continue; 4176 s = compute_blocknr(sh, j, 0); 4177 if (s < raid5_size(mddev, 0, 0)) { 4178 skipped_disk = 1; 4179 continue; 4180 } 4181 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE); 4182 set_bit(R5_Expanded, &sh->dev[j].flags); 4183 set_bit(R5_UPTODATE, &sh->dev[j].flags); 4184 } 4185 if (!skipped_disk) { 4186 set_bit(STRIPE_EXPAND_READY, &sh->state); 4187 set_bit(STRIPE_HANDLE, &sh->state); 4188 } 4189 list_add(&sh->lru, &stripes); 4190 } 4191 spin_lock_irq(&conf->device_lock); 4192 if (mddev->delta_disks < 0) 4193 conf->reshape_progress -= reshape_sectors * new_data_disks; 4194 else 4195 conf->reshape_progress += reshape_sectors * new_data_disks; 4196 spin_unlock_irq(&conf->device_lock); 4197 /* Ok, those stripe are ready. We can start scheduling 4198 * reads on the source stripes. 4199 * The source stripes are determined by mapping the first and last 4200 * block on the destination stripes. 4201 */ 4202 first_sector = 4203 raid5_compute_sector(conf, stripe_addr*(new_data_disks), 4204 1, &dd_idx, NULL); 4205 last_sector = 4206 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors) 4207 * new_data_disks - 1), 4208 1, &dd_idx, NULL); 4209 if (last_sector >= mddev->dev_sectors) 4210 last_sector = mddev->dev_sectors - 1; 4211 while (first_sector <= last_sector) { 4212 sh = get_active_stripe(conf, first_sector, 1, 0, 1); 4213 set_bit(STRIPE_EXPAND_SOURCE, &sh->state); 4214 set_bit(STRIPE_HANDLE, &sh->state); 4215 release_stripe(sh); 4216 first_sector += STRIPE_SECTORS; 4217 } 4218 /* Now that the sources are clearly marked, we can release 4219 * the destination stripes 4220 */ 4221 while (!list_empty(&stripes)) { 4222 sh = list_entry(stripes.next, struct stripe_head, lru); 4223 list_del_init(&sh->lru); 4224 release_stripe(sh); 4225 } 4226 /* If this takes us to the resync_max point where we have to pause, 4227 * then we need to write out the superblock. 4228 */ 4229 sector_nr += reshape_sectors; 4230 if ((sector_nr - mddev->curr_resync_completed) * 2 4231 >= mddev->resync_max - mddev->curr_resync_completed) { 4232 /* Cannot proceed until we've updated the superblock... */ 4233 wait_event(conf->wait_for_overlap, 4234 atomic_read(&conf->reshape_stripes) == 0); 4235 mddev->reshape_position = conf->reshape_progress; 4236 mddev->curr_resync_completed = mddev->curr_resync + reshape_sectors; 4237 conf->reshape_checkpoint = jiffies; 4238 set_bit(MD_CHANGE_DEVS, &mddev->flags); 4239 md_wakeup_thread(mddev->thread); 4240 wait_event(mddev->sb_wait, 4241 !test_bit(MD_CHANGE_DEVS, &mddev->flags) 4242 || kthread_should_stop()); 4243 spin_lock_irq(&conf->device_lock); 4244 conf->reshape_safe = mddev->reshape_position; 4245 spin_unlock_irq(&conf->device_lock); 4246 wake_up(&conf->wait_for_overlap); 4247 sysfs_notify(&mddev->kobj, NULL, "sync_completed"); 4248 } 4249 return reshape_sectors; 4250 } 4251 4252 /* FIXME go_faster isn't used */ 4253 static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) 4254 { 4255 raid5_conf_t *conf = mddev->private; 4256 struct stripe_head *sh; 4257 sector_t max_sector = mddev->dev_sectors; 4258 int sync_blocks; 4259 int still_degraded = 0; 4260 int i; 4261 4262 if (sector_nr >= max_sector) { 4263 /* just being told to finish up .. nothing much to do */ 4264 unplug_slaves(mddev); 4265 4266 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) { 4267 end_reshape(conf); 4268 return 0; 4269 } 4270 4271 if (mddev->curr_resync < max_sector) /* aborted */ 4272 bitmap_end_sync(mddev->bitmap, mddev->curr_resync, 4273 &sync_blocks, 1); 4274 else /* completed sync */ 4275 conf->fullsync = 0; 4276 bitmap_close_sync(mddev->bitmap); 4277 4278 return 0; 4279 } 4280 4281 /* Allow raid5_quiesce to complete */ 4282 wait_event(conf->wait_for_overlap, conf->quiesce != 2); 4283 4284 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) 4285 return reshape_request(mddev, sector_nr, skipped); 4286 4287 /* No need to check resync_max as we never do more than one 4288 * stripe, and as resync_max will always be on a chunk boundary, 4289 * if the check in md_do_sync didn't fire, there is no chance 4290 * of overstepping resync_max here 4291 */ 4292 4293 /* if there is too many failed drives and we are trying 4294 * to resync, then assert that we are finished, because there is 4295 * nothing we can do. 4296 */ 4297 if (mddev->degraded >= conf->max_degraded && 4298 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { 4299 sector_t rv = mddev->dev_sectors - sector_nr; 4300 *skipped = 1; 4301 return rv; 4302 } 4303 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && 4304 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && 4305 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { 4306 /* we can skip this block, and probably more */ 4307 sync_blocks /= STRIPE_SECTORS; 4308 *skipped = 1; 4309 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ 4310 } 4311 4312 4313 bitmap_cond_end_sync(mddev->bitmap, sector_nr); 4314 4315 sh = get_active_stripe(conf, sector_nr, 0, 1, 0); 4316 if (sh == NULL) { 4317 sh = get_active_stripe(conf, sector_nr, 0, 0, 0); 4318 /* make sure we don't swamp the stripe cache if someone else 4319 * is trying to get access 4320 */ 4321 schedule_timeout_uninterruptible(1); 4322 } 4323 /* Need to check if array will still be degraded after recovery/resync 4324 * We don't need to check the 'failed' flag as when that gets set, 4325 * recovery aborts. 4326 */ 4327 for (i = 0; i < conf->raid_disks; i++) 4328 if (conf->disks[i].rdev == NULL) 4329 still_degraded = 1; 4330 4331 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded); 4332 4333 spin_lock(&sh->lock); 4334 set_bit(STRIPE_SYNCING, &sh->state); 4335 clear_bit(STRIPE_INSYNC, &sh->state); 4336 spin_unlock(&sh->lock); 4337 4338 handle_stripe(sh); 4339 release_stripe(sh); 4340 4341 return STRIPE_SECTORS; 4342 } 4343 4344 static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) 4345 { 4346 /* We may not be able to submit a whole bio at once as there 4347 * may not be enough stripe_heads available. 4348 * We cannot pre-allocate enough stripe_heads as we may need 4349 * more than exist in the cache (if we allow ever large chunks). 4350 * So we do one stripe head at a time and record in 4351 * ->bi_hw_segments how many have been done. 4352 * 4353 * We *know* that this entire raid_bio is in one chunk, so 4354 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector. 4355 */ 4356 struct stripe_head *sh; 4357 int dd_idx; 4358 sector_t sector, logical_sector, last_sector; 4359 int scnt = 0; 4360 int remaining; 4361 int handled = 0; 4362 4363 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1); 4364 sector = raid5_compute_sector(conf, logical_sector, 4365 0, &dd_idx, NULL); 4366 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9); 4367 4368 for (; logical_sector < last_sector; 4369 logical_sector += STRIPE_SECTORS, 4370 sector += STRIPE_SECTORS, 4371 scnt++) { 4372 4373 if (scnt < raid5_bi_hw_segments(raid_bio)) 4374 /* already done this stripe */ 4375 continue; 4376 4377 sh = get_active_stripe(conf, sector, 0, 1, 0); 4378 4379 if (!sh) { 4380 /* failed to get a stripe - must wait */ 4381 raid5_set_bi_hw_segments(raid_bio, scnt); 4382 conf->retry_read_aligned = raid_bio; 4383 return handled; 4384 } 4385 4386 set_bit(R5_ReadError, &sh->dev[dd_idx].flags); 4387 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) { 4388 release_stripe(sh); 4389 raid5_set_bi_hw_segments(raid_bio, scnt); 4390 conf->retry_read_aligned = raid_bio; 4391 return handled; 4392 } 4393 4394 handle_stripe(sh); 4395 release_stripe(sh); 4396 handled++; 4397 } 4398 spin_lock_irq(&conf->device_lock); 4399 remaining = raid5_dec_bi_phys_segments(raid_bio); 4400 spin_unlock_irq(&conf->device_lock); 4401 if (remaining == 0) 4402 bio_endio(raid_bio, 0); 4403 if (atomic_dec_and_test(&conf->active_aligned_reads)) 4404 wake_up(&conf->wait_for_stripe); 4405 return handled; 4406 } 4407 4408 4409 /* 4410 * This is our raid5 kernel thread. 4411 * 4412 * We scan the hash table for stripes which can be handled now. 4413 * During the scan, completed stripes are saved for us by the interrupt 4414 * handler, so that they will not have to wait for our next wakeup. 4415 */ 4416 static void raid5d(mddev_t *mddev) 4417 { 4418 struct stripe_head *sh; 4419 raid5_conf_t *conf = mddev->private; 4420 int handled; 4421 4422 pr_debug("+++ raid5d active\n"); 4423 4424 md_check_recovery(mddev); 4425 4426 handled = 0; 4427 spin_lock_irq(&conf->device_lock); 4428 while (1) { 4429 struct bio *bio; 4430 4431 if (conf->seq_flush != conf->seq_write) { 4432 int seq = conf->seq_flush; 4433 spin_unlock_irq(&conf->device_lock); 4434 bitmap_unplug(mddev->bitmap); 4435 spin_lock_irq(&conf->device_lock); 4436 conf->seq_write = seq; 4437 activate_bit_delay(conf); 4438 } 4439 4440 while ((bio = remove_bio_from_retry(conf))) { 4441 int ok; 4442 spin_unlock_irq(&conf->device_lock); 4443 ok = retry_aligned_read(conf, bio); 4444 spin_lock_irq(&conf->device_lock); 4445 if (!ok) 4446 break; 4447 handled++; 4448 } 4449 4450 sh = __get_priority_stripe(conf); 4451 4452 if (!sh) 4453 break; 4454 spin_unlock_irq(&conf->device_lock); 4455 4456 handled++; 4457 handle_stripe(sh); 4458 release_stripe(sh); 4459 cond_resched(); 4460 4461 spin_lock_irq(&conf->device_lock); 4462 } 4463 pr_debug("%d stripes handled\n", handled); 4464 4465 spin_unlock_irq(&conf->device_lock); 4466 4467 async_tx_issue_pending_all(); 4468 unplug_slaves(mddev); 4469 4470 pr_debug("--- raid5d inactive\n"); 4471 } 4472 4473 static ssize_t 4474 raid5_show_stripe_cache_size(mddev_t *mddev, char *page) 4475 { 4476 raid5_conf_t *conf = mddev->private; 4477 if (conf) 4478 return sprintf(page, "%d\n", conf->max_nr_stripes); 4479 else 4480 return 0; 4481 } 4482 4483 static ssize_t 4484 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 4485 { 4486 raid5_conf_t *conf = mddev->private; 4487 unsigned long new; 4488 int err; 4489 4490 if (len >= PAGE_SIZE) 4491 return -EINVAL; 4492 if (!conf) 4493 return -ENODEV; 4494 4495 if (strict_strtoul(page, 10, &new)) 4496 return -EINVAL; 4497 if (new <= 16 || new > 32768) 4498 return -EINVAL; 4499 while (new < conf->max_nr_stripes) { 4500 if (drop_one_stripe(conf)) 4501 conf->max_nr_stripes--; 4502 else 4503 break; 4504 } 4505 err = md_allow_write(mddev); 4506 if (err) 4507 return err; 4508 while (new > conf->max_nr_stripes) { 4509 if (grow_one_stripe(conf)) 4510 conf->max_nr_stripes++; 4511 else break; 4512 } 4513 return len; 4514 } 4515 4516 static struct md_sysfs_entry 4517 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, 4518 raid5_show_stripe_cache_size, 4519 raid5_store_stripe_cache_size); 4520 4521 static ssize_t 4522 raid5_show_preread_threshold(mddev_t *mddev, char *page) 4523 { 4524 raid5_conf_t *conf = mddev->private; 4525 if (conf) 4526 return sprintf(page, "%d\n", conf->bypass_threshold); 4527 else 4528 return 0; 4529 } 4530 4531 static ssize_t 4532 raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len) 4533 { 4534 raid5_conf_t *conf = mddev->private; 4535 unsigned long new; 4536 if (len >= PAGE_SIZE) 4537 return -EINVAL; 4538 if (!conf) 4539 return -ENODEV; 4540 4541 if (strict_strtoul(page, 10, &new)) 4542 return -EINVAL; 4543 if (new > conf->max_nr_stripes) 4544 return -EINVAL; 4545 conf->bypass_threshold = new; 4546 return len; 4547 } 4548 4549 static struct md_sysfs_entry 4550 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold, 4551 S_IRUGO | S_IWUSR, 4552 raid5_show_preread_threshold, 4553 raid5_store_preread_threshold); 4554 4555 static ssize_t 4556 stripe_cache_active_show(mddev_t *mddev, char *page) 4557 { 4558 raid5_conf_t *conf = mddev->private; 4559 if (conf) 4560 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes)); 4561 else 4562 return 0; 4563 } 4564 4565 static struct md_sysfs_entry 4566 raid5_stripecache_active = __ATTR_RO(stripe_cache_active); 4567 4568 static struct attribute *raid5_attrs[] = { 4569 &raid5_stripecache_size.attr, 4570 &raid5_stripecache_active.attr, 4571 &raid5_preread_bypass_threshold.attr, 4572 NULL, 4573 }; 4574 static struct attribute_group raid5_attrs_group = { 4575 .name = NULL, 4576 .attrs = raid5_attrs, 4577 }; 4578 4579 static sector_t 4580 raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks) 4581 { 4582 raid5_conf_t *conf = mddev->private; 4583 4584 if (!sectors) 4585 sectors = mddev->dev_sectors; 4586 if (!raid_disks) 4587 /* size is defined by the smallest of previous and new size */ 4588 raid_disks = min(conf->raid_disks, conf->previous_raid_disks); 4589 4590 sectors &= ~((sector_t)mddev->chunk_sectors - 1); 4591 sectors &= ~((sector_t)mddev->new_chunk_sectors - 1); 4592 return sectors * (raid_disks - conf->max_degraded); 4593 } 4594 4595 static void raid5_free_percpu(raid5_conf_t *conf) 4596 { 4597 struct raid5_percpu *percpu; 4598 unsigned long cpu; 4599 4600 if (!conf->percpu) 4601 return; 4602 4603 get_online_cpus(); 4604 for_each_possible_cpu(cpu) { 4605 percpu = per_cpu_ptr(conf->percpu, cpu); 4606 safe_put_page(percpu->spare_page); 4607 kfree(percpu->scribble); 4608 } 4609 #ifdef CONFIG_HOTPLUG_CPU 4610 unregister_cpu_notifier(&conf->cpu_notify); 4611 #endif 4612 put_online_cpus(); 4613 4614 free_percpu(conf->percpu); 4615 } 4616 4617 static void free_conf(raid5_conf_t *conf) 4618 { 4619 shrink_stripes(conf); 4620 raid5_free_percpu(conf); 4621 kfree(conf->disks); 4622 kfree(conf->stripe_hashtbl); 4623 kfree(conf); 4624 } 4625 4626 #ifdef CONFIG_HOTPLUG_CPU 4627 static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action, 4628 void *hcpu) 4629 { 4630 raid5_conf_t *conf = container_of(nfb, raid5_conf_t, cpu_notify); 4631 long cpu = (long)hcpu; 4632 struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu); 4633 4634 switch (action) { 4635 case CPU_UP_PREPARE: 4636 case CPU_UP_PREPARE_FROZEN: 4637 if (conf->level == 6 && !percpu->spare_page) 4638 percpu->spare_page = alloc_page(GFP_KERNEL); 4639 if (!percpu->scribble) 4640 percpu->scribble = kmalloc(conf->scribble_len, GFP_KERNEL); 4641 4642 if (!percpu->scribble || 4643 (conf->level == 6 && !percpu->spare_page)) { 4644 safe_put_page(percpu->spare_page); 4645 kfree(percpu->scribble); 4646 pr_err("%s: failed memory allocation for cpu%ld\n", 4647 __func__, cpu); 4648 return notifier_from_errno(-ENOMEM); 4649 } 4650 break; 4651 case CPU_DEAD: 4652 case CPU_DEAD_FROZEN: 4653 safe_put_page(percpu->spare_page); 4654 kfree(percpu->scribble); 4655 percpu->spare_page = NULL; 4656 percpu->scribble = NULL; 4657 break; 4658 default: 4659 break; 4660 } 4661 return NOTIFY_OK; 4662 } 4663 #endif 4664 4665 static int raid5_alloc_percpu(raid5_conf_t *conf) 4666 { 4667 unsigned long cpu; 4668 struct page *spare_page; 4669 struct raid5_percpu __percpu *allcpus; 4670 void *scribble; 4671 int err; 4672 4673 allcpus = alloc_percpu(struct raid5_percpu); 4674 if (!allcpus) 4675 return -ENOMEM; 4676 conf->percpu = allcpus; 4677 4678 get_online_cpus(); 4679 err = 0; 4680 for_each_present_cpu(cpu) { 4681 if (conf->level == 6) { 4682 spare_page = alloc_page(GFP_KERNEL); 4683 if (!spare_page) { 4684 err = -ENOMEM; 4685 break; 4686 } 4687 per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page; 4688 } 4689 scribble = kmalloc(conf->scribble_len, GFP_KERNEL); 4690 if (!scribble) { 4691 err = -ENOMEM; 4692 break; 4693 } 4694 per_cpu_ptr(conf->percpu, cpu)->scribble = scribble; 4695 } 4696 #ifdef CONFIG_HOTPLUG_CPU 4697 conf->cpu_notify.notifier_call = raid456_cpu_notify; 4698 conf->cpu_notify.priority = 0; 4699 if (err == 0) 4700 err = register_cpu_notifier(&conf->cpu_notify); 4701 #endif 4702 put_online_cpus(); 4703 4704 return err; 4705 } 4706 4707 static raid5_conf_t *setup_conf(mddev_t *mddev) 4708 { 4709 raid5_conf_t *conf; 4710 int raid_disk, memory, max_disks; 4711 mdk_rdev_t *rdev; 4712 struct disk_info *disk; 4713 4714 if (mddev->new_level != 5 4715 && mddev->new_level != 4 4716 && mddev->new_level != 6) { 4717 printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n", 4718 mdname(mddev), mddev->new_level); 4719 return ERR_PTR(-EIO); 4720 } 4721 if ((mddev->new_level == 5 4722 && !algorithm_valid_raid5(mddev->new_layout)) || 4723 (mddev->new_level == 6 4724 && !algorithm_valid_raid6(mddev->new_layout))) { 4725 printk(KERN_ERR "md/raid:%s: layout %d not supported\n", 4726 mdname(mddev), mddev->new_layout); 4727 return ERR_PTR(-EIO); 4728 } 4729 if (mddev->new_level == 6 && mddev->raid_disks < 4) { 4730 printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n", 4731 mdname(mddev), mddev->raid_disks); 4732 return ERR_PTR(-EINVAL); 4733 } 4734 4735 if (!mddev->new_chunk_sectors || 4736 (mddev->new_chunk_sectors << 9) % PAGE_SIZE || 4737 !is_power_of_2(mddev->new_chunk_sectors)) { 4738 printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n", 4739 mdname(mddev), mddev->new_chunk_sectors << 9); 4740 return ERR_PTR(-EINVAL); 4741 } 4742 4743 conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL); 4744 if (conf == NULL) 4745 goto abort; 4746 spin_lock_init(&conf->device_lock); 4747 init_waitqueue_head(&conf->wait_for_stripe); 4748 init_waitqueue_head(&conf->wait_for_overlap); 4749 INIT_LIST_HEAD(&conf->handle_list); 4750 INIT_LIST_HEAD(&conf->hold_list); 4751 INIT_LIST_HEAD(&conf->delayed_list); 4752 INIT_LIST_HEAD(&conf->bitmap_list); 4753 INIT_LIST_HEAD(&conf->inactive_list); 4754 atomic_set(&conf->active_stripes, 0); 4755 atomic_set(&conf->preread_active_stripes, 0); 4756 atomic_set(&conf->active_aligned_reads, 0); 4757 conf->bypass_threshold = BYPASS_THRESHOLD; 4758 4759 conf->raid_disks = mddev->raid_disks; 4760 if (mddev->reshape_position == MaxSector) 4761 conf->previous_raid_disks = mddev->raid_disks; 4762 else 4763 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks; 4764 max_disks = max(conf->raid_disks, conf->previous_raid_disks); 4765 conf->scribble_len = scribble_len(max_disks); 4766 4767 conf->disks = kzalloc(max_disks * sizeof(struct disk_info), 4768 GFP_KERNEL); 4769 if (!conf->disks) 4770 goto abort; 4771 4772 conf->mddev = mddev; 4773 4774 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) 4775 goto abort; 4776 4777 conf->level = mddev->new_level; 4778 if (raid5_alloc_percpu(conf) != 0) 4779 goto abort; 4780 4781 pr_debug("raid456: run(%s) called.\n", mdname(mddev)); 4782 4783 list_for_each_entry(rdev, &mddev->disks, same_set) { 4784 raid_disk = rdev->raid_disk; 4785 if (raid_disk >= max_disks 4786 || raid_disk < 0) 4787 continue; 4788 disk = conf->disks + raid_disk; 4789 4790 disk->rdev = rdev; 4791 4792 if (test_bit(In_sync, &rdev->flags)) { 4793 char b[BDEVNAME_SIZE]; 4794 printk(KERN_INFO "md/raid:%s: device %s operational as raid" 4795 " disk %d\n", 4796 mdname(mddev), bdevname(rdev->bdev, b), raid_disk); 4797 } else 4798 /* Cannot rely on bitmap to complete recovery */ 4799 conf->fullsync = 1; 4800 } 4801 4802 conf->chunk_sectors = mddev->new_chunk_sectors; 4803 conf->level = mddev->new_level; 4804 if (conf->level == 6) 4805 conf->max_degraded = 2; 4806 else 4807 conf->max_degraded = 1; 4808 conf->algorithm = mddev->new_layout; 4809 conf->max_nr_stripes = NR_STRIPES; 4810 conf->reshape_progress = mddev->reshape_position; 4811 if (conf->reshape_progress != MaxSector) { 4812 conf->prev_chunk_sectors = mddev->chunk_sectors; 4813 conf->prev_algo = mddev->layout; 4814 } 4815 4816 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + 4817 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; 4818 if (grow_stripes(conf, conf->max_nr_stripes)) { 4819 printk(KERN_ERR 4820 "md/raid:%s: couldn't allocate %dkB for buffers\n", 4821 mdname(mddev), memory); 4822 goto abort; 4823 } else 4824 printk(KERN_INFO "md/raid:%s: allocated %dkB\n", 4825 mdname(mddev), memory); 4826 4827 conf->thread = md_register_thread(raid5d, mddev, NULL); 4828 if (!conf->thread) { 4829 printk(KERN_ERR 4830 "md/raid:%s: couldn't allocate thread.\n", 4831 mdname(mddev)); 4832 goto abort; 4833 } 4834 4835 return conf; 4836 4837 abort: 4838 if (conf) { 4839 free_conf(conf); 4840 return ERR_PTR(-EIO); 4841 } else 4842 return ERR_PTR(-ENOMEM); 4843 } 4844 4845 4846 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded) 4847 { 4848 switch (algo) { 4849 case ALGORITHM_PARITY_0: 4850 if (raid_disk < max_degraded) 4851 return 1; 4852 break; 4853 case ALGORITHM_PARITY_N: 4854 if (raid_disk >= raid_disks - max_degraded) 4855 return 1; 4856 break; 4857 case ALGORITHM_PARITY_0_6: 4858 if (raid_disk == 0 || 4859 raid_disk == raid_disks - 1) 4860 return 1; 4861 break; 4862 case ALGORITHM_LEFT_ASYMMETRIC_6: 4863 case ALGORITHM_RIGHT_ASYMMETRIC_6: 4864 case ALGORITHM_LEFT_SYMMETRIC_6: 4865 case ALGORITHM_RIGHT_SYMMETRIC_6: 4866 if (raid_disk == raid_disks - 1) 4867 return 1; 4868 } 4869 return 0; 4870 } 4871 4872 static int run(mddev_t *mddev) 4873 { 4874 raid5_conf_t *conf; 4875 int working_disks = 0, chunk_size; 4876 int dirty_parity_disks = 0; 4877 mdk_rdev_t *rdev; 4878 sector_t reshape_offset = 0; 4879 4880 if (mddev->recovery_cp != MaxSector) 4881 printk(KERN_NOTICE "md/raid:%s: not clean" 4882 " -- starting background reconstruction\n", 4883 mdname(mddev)); 4884 if (mddev->reshape_position != MaxSector) { 4885 /* Check that we can continue the reshape. 4886 * Currently only disks can change, it must 4887 * increase, and we must be past the point where 4888 * a stripe over-writes itself 4889 */ 4890 sector_t here_new, here_old; 4891 int old_disks; 4892 int max_degraded = (mddev->level == 6 ? 2 : 1); 4893 4894 if (mddev->new_level != mddev->level) { 4895 printk(KERN_ERR "md/raid:%s: unsupported reshape " 4896 "required - aborting.\n", 4897 mdname(mddev)); 4898 return -EINVAL; 4899 } 4900 old_disks = mddev->raid_disks - mddev->delta_disks; 4901 /* reshape_position must be on a new-stripe boundary, and one 4902 * further up in new geometry must map after here in old 4903 * geometry. 4904 */ 4905 here_new = mddev->reshape_position; 4906 if (sector_div(here_new, mddev->new_chunk_sectors * 4907 (mddev->raid_disks - max_degraded))) { 4908 printk(KERN_ERR "md/raid:%s: reshape_position not " 4909 "on a stripe boundary\n", mdname(mddev)); 4910 return -EINVAL; 4911 } 4912 reshape_offset = here_new * mddev->new_chunk_sectors; 4913 /* here_new is the stripe we will write to */ 4914 here_old = mddev->reshape_position; 4915 sector_div(here_old, mddev->chunk_sectors * 4916 (old_disks-max_degraded)); 4917 /* here_old is the first stripe that we might need to read 4918 * from */ 4919 if (mddev->delta_disks == 0) { 4920 /* We cannot be sure it is safe to start an in-place 4921 * reshape. It is only safe if user-space if monitoring 4922 * and taking constant backups. 4923 * mdadm always starts a situation like this in 4924 * readonly mode so it can take control before 4925 * allowing any writes. So just check for that. 4926 */ 4927 if ((here_new * mddev->new_chunk_sectors != 4928 here_old * mddev->chunk_sectors) || 4929 mddev->ro == 0) { 4930 printk(KERN_ERR "md/raid:%s: in-place reshape must be started" 4931 " in read-only mode - aborting\n", 4932 mdname(mddev)); 4933 return -EINVAL; 4934 } 4935 } else if (mddev->delta_disks < 0 4936 ? (here_new * mddev->new_chunk_sectors <= 4937 here_old * mddev->chunk_sectors) 4938 : (here_new * mddev->new_chunk_sectors >= 4939 here_old * mddev->chunk_sectors)) { 4940 /* Reading from the same stripe as writing to - bad */ 4941 printk(KERN_ERR "md/raid:%s: reshape_position too early for " 4942 "auto-recovery - aborting.\n", 4943 mdname(mddev)); 4944 return -EINVAL; 4945 } 4946 printk(KERN_INFO "md/raid:%s: reshape will continue\n", 4947 mdname(mddev)); 4948 /* OK, we should be able to continue; */ 4949 } else { 4950 BUG_ON(mddev->level != mddev->new_level); 4951 BUG_ON(mddev->layout != mddev->new_layout); 4952 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors); 4953 BUG_ON(mddev->delta_disks != 0); 4954 } 4955 4956 if (mddev->private == NULL) 4957 conf = setup_conf(mddev); 4958 else 4959 conf = mddev->private; 4960 4961 if (IS_ERR(conf)) 4962 return PTR_ERR(conf); 4963 4964 mddev->thread = conf->thread; 4965 conf->thread = NULL; 4966 mddev->private = conf; 4967 4968 /* 4969 * 0 for a fully functional array, 1 or 2 for a degraded array. 4970 */ 4971 list_for_each_entry(rdev, &mddev->disks, same_set) { 4972 if (rdev->raid_disk < 0) 4973 continue; 4974 if (test_bit(In_sync, &rdev->flags)) 4975 working_disks++; 4976 /* This disc is not fully in-sync. However if it 4977 * just stored parity (beyond the recovery_offset), 4978 * when we don't need to be concerned about the 4979 * array being dirty. 4980 * When reshape goes 'backwards', we never have 4981 * partially completed devices, so we only need 4982 * to worry about reshape going forwards. 4983 */ 4984 /* Hack because v0.91 doesn't store recovery_offset properly. */ 4985 if (mddev->major_version == 0 && 4986 mddev->minor_version > 90) 4987 rdev->recovery_offset = reshape_offset; 4988 4989 if (rdev->recovery_offset < reshape_offset) { 4990 /* We need to check old and new layout */ 4991 if (!only_parity(rdev->raid_disk, 4992 conf->algorithm, 4993 conf->raid_disks, 4994 conf->max_degraded)) 4995 continue; 4996 } 4997 if (!only_parity(rdev->raid_disk, 4998 conf->prev_algo, 4999 conf->previous_raid_disks, 5000 conf->max_degraded)) 5001 continue; 5002 dirty_parity_disks++; 5003 } 5004 5005 mddev->degraded = (max(conf->raid_disks, conf->previous_raid_disks) 5006 - working_disks); 5007 5008 if (mddev->degraded > conf->max_degraded) { 5009 printk(KERN_ERR "md/raid:%s: not enough operational devices" 5010 " (%d/%d failed)\n", 5011 mdname(mddev), mddev->degraded, conf->raid_disks); 5012 goto abort; 5013 } 5014 5015 /* device size must be a multiple of chunk size */ 5016 mddev->dev_sectors &= ~(mddev->chunk_sectors - 1); 5017 mddev->resync_max_sectors = mddev->dev_sectors; 5018 5019 if (mddev->degraded > dirty_parity_disks && 5020 mddev->recovery_cp != MaxSector) { 5021 if (mddev->ok_start_degraded) 5022 printk(KERN_WARNING 5023 "md/raid:%s: starting dirty degraded array" 5024 " - data corruption possible.\n", 5025 mdname(mddev)); 5026 else { 5027 printk(KERN_ERR 5028 "md/raid:%s: cannot start dirty degraded array.\n", 5029 mdname(mddev)); 5030 goto abort; 5031 } 5032 } 5033 5034 if (mddev->degraded == 0) 5035 printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d" 5036 " devices, algorithm %d\n", mdname(mddev), conf->level, 5037 mddev->raid_disks-mddev->degraded, mddev->raid_disks, 5038 mddev->new_layout); 5039 else 5040 printk(KERN_ALERT "md/raid:%s: raid level %d active with %d" 5041 " out of %d devices, algorithm %d\n", 5042 mdname(mddev), conf->level, 5043 mddev->raid_disks - mddev->degraded, 5044 mddev->raid_disks, mddev->new_layout); 5045 5046 print_raid5_conf(conf); 5047 5048 if (conf->reshape_progress != MaxSector) { 5049 conf->reshape_safe = conf->reshape_progress; 5050 atomic_set(&conf->reshape_stripes, 0); 5051 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 5052 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 5053 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 5054 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 5055 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 5056 "reshape"); 5057 } 5058 5059 /* read-ahead size must cover two whole stripes, which is 5060 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 5061 */ 5062 { 5063 int data_disks = conf->previous_raid_disks - conf->max_degraded; 5064 int stripe = data_disks * 5065 ((mddev->chunk_sectors << 9) / PAGE_SIZE); 5066 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 5067 mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 5068 } 5069 5070 /* Ok, everything is just fine now */ 5071 if (mddev->to_remove == &raid5_attrs_group) 5072 mddev->to_remove = NULL; 5073 else if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group)) 5074 printk(KERN_WARNING 5075 "md/raid:%s: failed to create sysfs attributes.\n", 5076 mdname(mddev)); 5077 5078 mddev->queue->queue_lock = &conf->device_lock; 5079 5080 mddev->queue->unplug_fn = raid5_unplug_device; 5081 mddev->queue->backing_dev_info.congested_data = mddev; 5082 mddev->queue->backing_dev_info.congested_fn = raid5_congested; 5083 5084 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0)); 5085 5086 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); 5087 chunk_size = mddev->chunk_sectors << 9; 5088 blk_queue_io_min(mddev->queue, chunk_size); 5089 blk_queue_io_opt(mddev->queue, chunk_size * 5090 (conf->raid_disks - conf->max_degraded)); 5091 5092 list_for_each_entry(rdev, &mddev->disks, same_set) 5093 disk_stack_limits(mddev->gendisk, rdev->bdev, 5094 rdev->data_offset << 9); 5095 5096 return 0; 5097 abort: 5098 md_unregister_thread(mddev->thread); 5099 mddev->thread = NULL; 5100 if (conf) { 5101 print_raid5_conf(conf); 5102 free_conf(conf); 5103 } 5104 mddev->private = NULL; 5105 printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev)); 5106 return -EIO; 5107 } 5108 5109 static int stop(mddev_t *mddev) 5110 { 5111 raid5_conf_t *conf = mddev->private; 5112 5113 md_unregister_thread(mddev->thread); 5114 mddev->thread = NULL; 5115 mddev->queue->backing_dev_info.congested_fn = NULL; 5116 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ 5117 free_conf(conf); 5118 mddev->private = NULL; 5119 mddev->to_remove = &raid5_attrs_group; 5120 return 0; 5121 } 5122 5123 #ifdef DEBUG 5124 static void print_sh(struct seq_file *seq, struct stripe_head *sh) 5125 { 5126 int i; 5127 5128 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n", 5129 (unsigned long long)sh->sector, sh->pd_idx, sh->state); 5130 seq_printf(seq, "sh %llu, count %d.\n", 5131 (unsigned long long)sh->sector, atomic_read(&sh->count)); 5132 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector); 5133 for (i = 0; i < sh->disks; i++) { 5134 seq_printf(seq, "(cache%d: %p %ld) ", 5135 i, sh->dev[i].page, sh->dev[i].flags); 5136 } 5137 seq_printf(seq, "\n"); 5138 } 5139 5140 static void printall(struct seq_file *seq, raid5_conf_t *conf) 5141 { 5142 struct stripe_head *sh; 5143 struct hlist_node *hn; 5144 int i; 5145 5146 spin_lock_irq(&conf->device_lock); 5147 for (i = 0; i < NR_HASH; i++) { 5148 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) { 5149 if (sh->raid_conf != conf) 5150 continue; 5151 print_sh(seq, sh); 5152 } 5153 } 5154 spin_unlock_irq(&conf->device_lock); 5155 } 5156 #endif 5157 5158 static void status(struct seq_file *seq, mddev_t *mddev) 5159 { 5160 raid5_conf_t *conf = mddev->private; 5161 int i; 5162 5163 seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level, 5164 mddev->chunk_sectors / 2, mddev->layout); 5165 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); 5166 for (i = 0; i < conf->raid_disks; i++) 5167 seq_printf (seq, "%s", 5168 conf->disks[i].rdev && 5169 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_"); 5170 seq_printf (seq, "]"); 5171 #ifdef DEBUG 5172 seq_printf (seq, "\n"); 5173 printall(seq, conf); 5174 #endif 5175 } 5176 5177 static void print_raid5_conf (raid5_conf_t *conf) 5178 { 5179 int i; 5180 struct disk_info *tmp; 5181 5182 printk(KERN_DEBUG "RAID conf printout:\n"); 5183 if (!conf) { 5184 printk("(conf==NULL)\n"); 5185 return; 5186 } 5187 printk(KERN_DEBUG " --- level:%d rd:%d wd:%d\n", conf->level, 5188 conf->raid_disks, 5189 conf->raid_disks - conf->mddev->degraded); 5190 5191 for (i = 0; i < conf->raid_disks; i++) { 5192 char b[BDEVNAME_SIZE]; 5193 tmp = conf->disks + i; 5194 if (tmp->rdev) 5195 printk(KERN_DEBUG " disk %d, o:%d, dev:%s\n", 5196 i, !test_bit(Faulty, &tmp->rdev->flags), 5197 bdevname(tmp->rdev->bdev, b)); 5198 } 5199 } 5200 5201 static int raid5_spare_active(mddev_t *mddev) 5202 { 5203 int i; 5204 raid5_conf_t *conf = mddev->private; 5205 struct disk_info *tmp; 5206 5207 for (i = 0; i < conf->raid_disks; i++) { 5208 tmp = conf->disks + i; 5209 if (tmp->rdev 5210 && !test_bit(Faulty, &tmp->rdev->flags) 5211 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { 5212 unsigned long flags; 5213 spin_lock_irqsave(&conf->device_lock, flags); 5214 mddev->degraded--; 5215 spin_unlock_irqrestore(&conf->device_lock, flags); 5216 } 5217 } 5218 print_raid5_conf(conf); 5219 return 0; 5220 } 5221 5222 static int raid5_remove_disk(mddev_t *mddev, int number) 5223 { 5224 raid5_conf_t *conf = mddev->private; 5225 int err = 0; 5226 mdk_rdev_t *rdev; 5227 struct disk_info *p = conf->disks + number; 5228 5229 print_raid5_conf(conf); 5230 rdev = p->rdev; 5231 if (rdev) { 5232 if (number >= conf->raid_disks && 5233 conf->reshape_progress == MaxSector) 5234 clear_bit(In_sync, &rdev->flags); 5235 5236 if (test_bit(In_sync, &rdev->flags) || 5237 atomic_read(&rdev->nr_pending)) { 5238 err = -EBUSY; 5239 goto abort; 5240 } 5241 /* Only remove non-faulty devices if recovery 5242 * isn't possible. 5243 */ 5244 if (!test_bit(Faulty, &rdev->flags) && 5245 mddev->degraded <= conf->max_degraded && 5246 number < conf->raid_disks) { 5247 err = -EBUSY; 5248 goto abort; 5249 } 5250 p->rdev = NULL; 5251 synchronize_rcu(); 5252 if (atomic_read(&rdev->nr_pending)) { 5253 /* lost the race, try later */ 5254 err = -EBUSY; 5255 p->rdev = rdev; 5256 } 5257 } 5258 abort: 5259 5260 print_raid5_conf(conf); 5261 return err; 5262 } 5263 5264 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 5265 { 5266 raid5_conf_t *conf = mddev->private; 5267 int err = -EEXIST; 5268 int disk; 5269 struct disk_info *p; 5270 int first = 0; 5271 int last = conf->raid_disks - 1; 5272 5273 if (mddev->degraded > conf->max_degraded) 5274 /* no point adding a device */ 5275 return -EINVAL; 5276 5277 if (rdev->raid_disk >= 0) 5278 first = last = rdev->raid_disk; 5279 5280 /* 5281 * find the disk ... but prefer rdev->saved_raid_disk 5282 * if possible. 5283 */ 5284 if (rdev->saved_raid_disk >= 0 && 5285 rdev->saved_raid_disk >= first && 5286 conf->disks[rdev->saved_raid_disk].rdev == NULL) 5287 disk = rdev->saved_raid_disk; 5288 else 5289 disk = first; 5290 for ( ; disk <= last ; disk++) 5291 if ((p=conf->disks + disk)->rdev == NULL) { 5292 clear_bit(In_sync, &rdev->flags); 5293 rdev->raid_disk = disk; 5294 err = 0; 5295 if (rdev->saved_raid_disk != disk) 5296 conf->fullsync = 1; 5297 rcu_assign_pointer(p->rdev, rdev); 5298 break; 5299 } 5300 print_raid5_conf(conf); 5301 return err; 5302 } 5303 5304 static int raid5_resize(mddev_t *mddev, sector_t sectors) 5305 { 5306 /* no resync is happening, and there is enough space 5307 * on all devices, so we can resize. 5308 * We need to make sure resync covers any new space. 5309 * If the array is shrinking we should possibly wait until 5310 * any io in the removed space completes, but it hardly seems 5311 * worth it. 5312 */ 5313 sectors &= ~((sector_t)mddev->chunk_sectors - 1); 5314 md_set_array_sectors(mddev, raid5_size(mddev, sectors, 5315 mddev->raid_disks)); 5316 if (mddev->array_sectors > 5317 raid5_size(mddev, sectors, mddev->raid_disks)) 5318 return -EINVAL; 5319 set_capacity(mddev->gendisk, mddev->array_sectors); 5320 revalidate_disk(mddev->gendisk); 5321 if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) { 5322 mddev->recovery_cp = mddev->dev_sectors; 5323 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); 5324 } 5325 mddev->dev_sectors = sectors; 5326 mddev->resync_max_sectors = sectors; 5327 return 0; 5328 } 5329 5330 static int check_stripe_cache(mddev_t *mddev) 5331 { 5332 /* Can only proceed if there are plenty of stripe_heads. 5333 * We need a minimum of one full stripe,, and for sensible progress 5334 * it is best to have about 4 times that. 5335 * If we require 4 times, then the default 256 4K stripe_heads will 5336 * allow for chunk sizes up to 256K, which is probably OK. 5337 * If the chunk size is greater, user-space should request more 5338 * stripe_heads first. 5339 */ 5340 raid5_conf_t *conf = mddev->private; 5341 if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4 5342 > conf->max_nr_stripes || 5343 ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4 5344 > conf->max_nr_stripes) { 5345 printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes. Needed %lu\n", 5346 mdname(mddev), 5347 ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9) 5348 / STRIPE_SIZE)*4); 5349 return 0; 5350 } 5351 return 1; 5352 } 5353 5354 static int check_reshape(mddev_t *mddev) 5355 { 5356 raid5_conf_t *conf = mddev->private; 5357 5358 if (mddev->delta_disks == 0 && 5359 mddev->new_layout == mddev->layout && 5360 mddev->new_chunk_sectors == mddev->chunk_sectors) 5361 return 0; /* nothing to do */ 5362 if (mddev->bitmap) 5363 /* Cannot grow a bitmap yet */ 5364 return -EBUSY; 5365 if (mddev->degraded > conf->max_degraded) 5366 return -EINVAL; 5367 if (mddev->delta_disks < 0) { 5368 /* We might be able to shrink, but the devices must 5369 * be made bigger first. 5370 * For raid6, 4 is the minimum size. 5371 * Otherwise 2 is the minimum 5372 */ 5373 int min = 2; 5374 if (mddev->level == 6) 5375 min = 4; 5376 if (mddev->raid_disks + mddev->delta_disks < min) 5377 return -EINVAL; 5378 } 5379 5380 if (!check_stripe_cache(mddev)) 5381 return -ENOSPC; 5382 5383 return resize_stripes(conf, conf->raid_disks + mddev->delta_disks); 5384 } 5385 5386 static int raid5_start_reshape(mddev_t *mddev) 5387 { 5388 raid5_conf_t *conf = mddev->private; 5389 mdk_rdev_t *rdev; 5390 int spares = 0; 5391 int added_devices = 0; 5392 unsigned long flags; 5393 5394 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 5395 return -EBUSY; 5396 5397 if (!check_stripe_cache(mddev)) 5398 return -ENOSPC; 5399 5400 list_for_each_entry(rdev, &mddev->disks, same_set) 5401 if (rdev->raid_disk < 0 && 5402 !test_bit(Faulty, &rdev->flags)) 5403 spares++; 5404 5405 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded) 5406 /* Not enough devices even to make a degraded array 5407 * of that size 5408 */ 5409 return -EINVAL; 5410 5411 /* Refuse to reduce size of the array. Any reductions in 5412 * array size must be through explicit setting of array_size 5413 * attribute. 5414 */ 5415 if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks) 5416 < mddev->array_sectors) { 5417 printk(KERN_ERR "md/raid:%s: array size must be reduced " 5418 "before number of disks\n", mdname(mddev)); 5419 return -EINVAL; 5420 } 5421 5422 atomic_set(&conf->reshape_stripes, 0); 5423 spin_lock_irq(&conf->device_lock); 5424 conf->previous_raid_disks = conf->raid_disks; 5425 conf->raid_disks += mddev->delta_disks; 5426 conf->prev_chunk_sectors = conf->chunk_sectors; 5427 conf->chunk_sectors = mddev->new_chunk_sectors; 5428 conf->prev_algo = conf->algorithm; 5429 conf->algorithm = mddev->new_layout; 5430 if (mddev->delta_disks < 0) 5431 conf->reshape_progress = raid5_size(mddev, 0, 0); 5432 else 5433 conf->reshape_progress = 0; 5434 conf->reshape_safe = conf->reshape_progress; 5435 conf->generation++; 5436 spin_unlock_irq(&conf->device_lock); 5437 5438 /* Add some new drives, as many as will fit. 5439 * We know there are enough to make the newly sized array work. 5440 */ 5441 list_for_each_entry(rdev, &mddev->disks, same_set) 5442 if (rdev->raid_disk < 0 && 5443 !test_bit(Faulty, &rdev->flags)) { 5444 if (raid5_add_disk(mddev, rdev) == 0) { 5445 char nm[20]; 5446 if (rdev->raid_disk >= conf->previous_raid_disks) { 5447 set_bit(In_sync, &rdev->flags); 5448 added_devices++; 5449 } else 5450 rdev->recovery_offset = 0; 5451 sprintf(nm, "rd%d", rdev->raid_disk); 5452 if (sysfs_create_link(&mddev->kobj, 5453 &rdev->kobj, nm)) 5454 printk(KERN_WARNING 5455 "md/raid:%s: failed to create " 5456 " link %s\n", 5457 mdname(mddev), nm); 5458 } else 5459 break; 5460 } 5461 5462 /* When a reshape changes the number of devices, ->degraded 5463 * is measured against the large of the pre and post number of 5464 * devices.*/ 5465 if (mddev->delta_disks > 0) { 5466 spin_lock_irqsave(&conf->device_lock, flags); 5467 mddev->degraded += (conf->raid_disks - conf->previous_raid_disks) 5468 - added_devices; 5469 spin_unlock_irqrestore(&conf->device_lock, flags); 5470 } 5471 mddev->raid_disks = conf->raid_disks; 5472 mddev->reshape_position = conf->reshape_progress; 5473 set_bit(MD_CHANGE_DEVS, &mddev->flags); 5474 5475 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); 5476 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); 5477 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); 5478 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); 5479 mddev->sync_thread = md_register_thread(md_do_sync, mddev, 5480 "reshape"); 5481 if (!mddev->sync_thread) { 5482 mddev->recovery = 0; 5483 spin_lock_irq(&conf->device_lock); 5484 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; 5485 conf->reshape_progress = MaxSector; 5486 spin_unlock_irq(&conf->device_lock); 5487 return -EAGAIN; 5488 } 5489 conf->reshape_checkpoint = jiffies; 5490 md_wakeup_thread(mddev->sync_thread); 5491 md_new_event(mddev); 5492 return 0; 5493 } 5494 5495 /* This is called from the reshape thread and should make any 5496 * changes needed in 'conf' 5497 */ 5498 static void end_reshape(raid5_conf_t *conf) 5499 { 5500 5501 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) { 5502 5503 spin_lock_irq(&conf->device_lock); 5504 conf->previous_raid_disks = conf->raid_disks; 5505 conf->reshape_progress = MaxSector; 5506 spin_unlock_irq(&conf->device_lock); 5507 wake_up(&conf->wait_for_overlap); 5508 5509 /* read-ahead size must cover two whole stripes, which is 5510 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices 5511 */ 5512 { 5513 int data_disks = conf->raid_disks - conf->max_degraded; 5514 int stripe = data_disks * ((conf->chunk_sectors << 9) 5515 / PAGE_SIZE); 5516 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe) 5517 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe; 5518 } 5519 } 5520 } 5521 5522 /* This is called from the raid5d thread with mddev_lock held. 5523 * It makes config changes to the device. 5524 */ 5525 static void raid5_finish_reshape(mddev_t *mddev) 5526 { 5527 raid5_conf_t *conf = mddev->private; 5528 5529 if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { 5530 5531 if (mddev->delta_disks > 0) { 5532 md_set_array_sectors(mddev, raid5_size(mddev, 0, 0)); 5533 set_capacity(mddev->gendisk, mddev->array_sectors); 5534 revalidate_disk(mddev->gendisk); 5535 } else { 5536 int d; 5537 mddev->degraded = conf->raid_disks; 5538 for (d = 0; d < conf->raid_disks ; d++) 5539 if (conf->disks[d].rdev && 5540 test_bit(In_sync, 5541 &conf->disks[d].rdev->flags)) 5542 mddev->degraded--; 5543 for (d = conf->raid_disks ; 5544 d < conf->raid_disks - mddev->delta_disks; 5545 d++) { 5546 mdk_rdev_t *rdev = conf->disks[d].rdev; 5547 if (rdev && raid5_remove_disk(mddev, d) == 0) { 5548 char nm[20]; 5549 sprintf(nm, "rd%d", rdev->raid_disk); 5550 sysfs_remove_link(&mddev->kobj, nm); 5551 rdev->raid_disk = -1; 5552 } 5553 } 5554 } 5555 mddev->layout = conf->algorithm; 5556 mddev->chunk_sectors = conf->chunk_sectors; 5557 mddev->reshape_position = MaxSector; 5558 mddev->delta_disks = 0; 5559 } 5560 } 5561 5562 static void raid5_quiesce(mddev_t *mddev, int state) 5563 { 5564 raid5_conf_t *conf = mddev->private; 5565 5566 switch(state) { 5567 case 2: /* resume for a suspend */ 5568 wake_up(&conf->wait_for_overlap); 5569 break; 5570 5571 case 1: /* stop all writes */ 5572 spin_lock_irq(&conf->device_lock); 5573 /* '2' tells resync/reshape to pause so that all 5574 * active stripes can drain 5575 */ 5576 conf->quiesce = 2; 5577 wait_event_lock_irq(conf->wait_for_stripe, 5578 atomic_read(&conf->active_stripes) == 0 && 5579 atomic_read(&conf->active_aligned_reads) == 0, 5580 conf->device_lock, /* nothing */); 5581 conf->quiesce = 1; 5582 spin_unlock_irq(&conf->device_lock); 5583 /* allow reshape to continue */ 5584 wake_up(&conf->wait_for_overlap); 5585 break; 5586 5587 case 0: /* re-enable writes */ 5588 spin_lock_irq(&conf->device_lock); 5589 conf->quiesce = 0; 5590 wake_up(&conf->wait_for_stripe); 5591 wake_up(&conf->wait_for_overlap); 5592 spin_unlock_irq(&conf->device_lock); 5593 break; 5594 } 5595 } 5596 5597 5598 static void *raid45_takeover_raid0(mddev_t *mddev, int level) 5599 { 5600 struct raid0_private_data *raid0_priv = mddev->private; 5601 5602 /* for raid0 takeover only one zone is supported */ 5603 if (raid0_priv->nr_strip_zones > 1) { 5604 printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n", 5605 mdname(mddev)); 5606 return ERR_PTR(-EINVAL); 5607 } 5608 5609 mddev->new_level = level; 5610 mddev->new_layout = ALGORITHM_PARITY_N; 5611 mddev->new_chunk_sectors = mddev->chunk_sectors; 5612 mddev->raid_disks += 1; 5613 mddev->delta_disks = 1; 5614 /* make sure it will be not marked as dirty */ 5615 mddev->recovery_cp = MaxSector; 5616 5617 return setup_conf(mddev); 5618 } 5619 5620 5621 static void *raid5_takeover_raid1(mddev_t *mddev) 5622 { 5623 int chunksect; 5624 5625 if (mddev->raid_disks != 2 || 5626 mddev->degraded > 1) 5627 return ERR_PTR(-EINVAL); 5628 5629 /* Should check if there are write-behind devices? */ 5630 5631 chunksect = 64*2; /* 64K by default */ 5632 5633 /* The array must be an exact multiple of chunksize */ 5634 while (chunksect && (mddev->array_sectors & (chunksect-1))) 5635 chunksect >>= 1; 5636 5637 if ((chunksect<<9) < STRIPE_SIZE) 5638 /* array size does not allow a suitable chunk size */ 5639 return ERR_PTR(-EINVAL); 5640 5641 mddev->new_level = 5; 5642 mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC; 5643 mddev->new_chunk_sectors = chunksect; 5644 5645 return setup_conf(mddev); 5646 } 5647 5648 static void *raid5_takeover_raid6(mddev_t *mddev) 5649 { 5650 int new_layout; 5651 5652 switch (mddev->layout) { 5653 case ALGORITHM_LEFT_ASYMMETRIC_6: 5654 new_layout = ALGORITHM_LEFT_ASYMMETRIC; 5655 break; 5656 case ALGORITHM_RIGHT_ASYMMETRIC_6: 5657 new_layout = ALGORITHM_RIGHT_ASYMMETRIC; 5658 break; 5659 case ALGORITHM_LEFT_SYMMETRIC_6: 5660 new_layout = ALGORITHM_LEFT_SYMMETRIC; 5661 break; 5662 case ALGORITHM_RIGHT_SYMMETRIC_6: 5663 new_layout = ALGORITHM_RIGHT_SYMMETRIC; 5664 break; 5665 case ALGORITHM_PARITY_0_6: 5666 new_layout = ALGORITHM_PARITY_0; 5667 break; 5668 case ALGORITHM_PARITY_N: 5669 new_layout = ALGORITHM_PARITY_N; 5670 break; 5671 default: 5672 return ERR_PTR(-EINVAL); 5673 } 5674 mddev->new_level = 5; 5675 mddev->new_layout = new_layout; 5676 mddev->delta_disks = -1; 5677 mddev->raid_disks -= 1; 5678 return setup_conf(mddev); 5679 } 5680 5681 5682 static int raid5_check_reshape(mddev_t *mddev) 5683 { 5684 /* For a 2-drive array, the layout and chunk size can be changed 5685 * immediately as not restriping is needed. 5686 * For larger arrays we record the new value - after validation 5687 * to be used by a reshape pass. 5688 */ 5689 raid5_conf_t *conf = mddev->private; 5690 int new_chunk = mddev->new_chunk_sectors; 5691 5692 if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout)) 5693 return -EINVAL; 5694 if (new_chunk > 0) { 5695 if (!is_power_of_2(new_chunk)) 5696 return -EINVAL; 5697 if (new_chunk < (PAGE_SIZE>>9)) 5698 return -EINVAL; 5699 if (mddev->array_sectors & (new_chunk-1)) 5700 /* not factor of array size */ 5701 return -EINVAL; 5702 } 5703 5704 /* They look valid */ 5705 5706 if (mddev->raid_disks == 2) { 5707 /* can make the change immediately */ 5708 if (mddev->new_layout >= 0) { 5709 conf->algorithm = mddev->new_layout; 5710 mddev->layout = mddev->new_layout; 5711 } 5712 if (new_chunk > 0) { 5713 conf->chunk_sectors = new_chunk ; 5714 mddev->chunk_sectors = new_chunk; 5715 } 5716 set_bit(MD_CHANGE_DEVS, &mddev->flags); 5717 md_wakeup_thread(mddev->thread); 5718 } 5719 return check_reshape(mddev); 5720 } 5721 5722 static int raid6_check_reshape(mddev_t *mddev) 5723 { 5724 int new_chunk = mddev->new_chunk_sectors; 5725 5726 if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout)) 5727 return -EINVAL; 5728 if (new_chunk > 0) { 5729 if (!is_power_of_2(new_chunk)) 5730 return -EINVAL; 5731 if (new_chunk < (PAGE_SIZE >> 9)) 5732 return -EINVAL; 5733 if (mddev->array_sectors & (new_chunk-1)) 5734 /* not factor of array size */ 5735 return -EINVAL; 5736 } 5737 5738 /* They look valid */ 5739 return check_reshape(mddev); 5740 } 5741 5742 static void *raid5_takeover(mddev_t *mddev) 5743 { 5744 /* raid5 can take over: 5745 * raid0 - if there is only one strip zone - make it a raid4 layout 5746 * raid1 - if there are two drives. We need to know the chunk size 5747 * raid4 - trivial - just use a raid4 layout. 5748 * raid6 - Providing it is a *_6 layout 5749 */ 5750 if (mddev->level == 0) 5751 return raid45_takeover_raid0(mddev, 5); 5752 if (mddev->level == 1) 5753 return raid5_takeover_raid1(mddev); 5754 if (mddev->level == 4) { 5755 mddev->new_layout = ALGORITHM_PARITY_N; 5756 mddev->new_level = 5; 5757 return setup_conf(mddev); 5758 } 5759 if (mddev->level == 6) 5760 return raid5_takeover_raid6(mddev); 5761 5762 return ERR_PTR(-EINVAL); 5763 } 5764 5765 static void *raid4_takeover(mddev_t *mddev) 5766 { 5767 /* raid4 can take over: 5768 * raid0 - if there is only one strip zone 5769 * raid5 - if layout is right 5770 */ 5771 if (mddev->level == 0) 5772 return raid45_takeover_raid0(mddev, 4); 5773 if (mddev->level == 5 && 5774 mddev->layout == ALGORITHM_PARITY_N) { 5775 mddev->new_layout = 0; 5776 mddev->new_level = 4; 5777 return setup_conf(mddev); 5778 } 5779 return ERR_PTR(-EINVAL); 5780 } 5781 5782 static struct mdk_personality raid5_personality; 5783 5784 static void *raid6_takeover(mddev_t *mddev) 5785 { 5786 /* Currently can only take over a raid5. We map the 5787 * personality to an equivalent raid6 personality 5788 * with the Q block at the end. 5789 */ 5790 int new_layout; 5791 5792 if (mddev->pers != &raid5_personality) 5793 return ERR_PTR(-EINVAL); 5794 if (mddev->degraded > 1) 5795 return ERR_PTR(-EINVAL); 5796 if (mddev->raid_disks > 253) 5797 return ERR_PTR(-EINVAL); 5798 if (mddev->raid_disks < 3) 5799 return ERR_PTR(-EINVAL); 5800 5801 switch (mddev->layout) { 5802 case ALGORITHM_LEFT_ASYMMETRIC: 5803 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6; 5804 break; 5805 case ALGORITHM_RIGHT_ASYMMETRIC: 5806 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6; 5807 break; 5808 case ALGORITHM_LEFT_SYMMETRIC: 5809 new_layout = ALGORITHM_LEFT_SYMMETRIC_6; 5810 break; 5811 case ALGORITHM_RIGHT_SYMMETRIC: 5812 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6; 5813 break; 5814 case ALGORITHM_PARITY_0: 5815 new_layout = ALGORITHM_PARITY_0_6; 5816 break; 5817 case ALGORITHM_PARITY_N: 5818 new_layout = ALGORITHM_PARITY_N; 5819 break; 5820 default: 5821 return ERR_PTR(-EINVAL); 5822 } 5823 mddev->new_level = 6; 5824 mddev->new_layout = new_layout; 5825 mddev->delta_disks = 1; 5826 mddev->raid_disks += 1; 5827 return setup_conf(mddev); 5828 } 5829 5830 5831 static struct mdk_personality raid6_personality = 5832 { 5833 .name = "raid6", 5834 .level = 6, 5835 .owner = THIS_MODULE, 5836 .make_request = make_request, 5837 .run = run, 5838 .stop = stop, 5839 .status = status, 5840 .error_handler = error, 5841 .hot_add_disk = raid5_add_disk, 5842 .hot_remove_disk= raid5_remove_disk, 5843 .spare_active = raid5_spare_active, 5844 .sync_request = sync_request, 5845 .resize = raid5_resize, 5846 .size = raid5_size, 5847 .check_reshape = raid6_check_reshape, 5848 .start_reshape = raid5_start_reshape, 5849 .finish_reshape = raid5_finish_reshape, 5850 .quiesce = raid5_quiesce, 5851 .takeover = raid6_takeover, 5852 }; 5853 static struct mdk_personality raid5_personality = 5854 { 5855 .name = "raid5", 5856 .level = 5, 5857 .owner = THIS_MODULE, 5858 .make_request = make_request, 5859 .run = run, 5860 .stop = stop, 5861 .status = status, 5862 .error_handler = error, 5863 .hot_add_disk = raid5_add_disk, 5864 .hot_remove_disk= raid5_remove_disk, 5865 .spare_active = raid5_spare_active, 5866 .sync_request = sync_request, 5867 .resize = raid5_resize, 5868 .size = raid5_size, 5869 .check_reshape = raid5_check_reshape, 5870 .start_reshape = raid5_start_reshape, 5871 .finish_reshape = raid5_finish_reshape, 5872 .quiesce = raid5_quiesce, 5873 .takeover = raid5_takeover, 5874 }; 5875 5876 static struct mdk_personality raid4_personality = 5877 { 5878 .name = "raid4", 5879 .level = 4, 5880 .owner = THIS_MODULE, 5881 .make_request = make_request, 5882 .run = run, 5883 .stop = stop, 5884 .status = status, 5885 .error_handler = error, 5886 .hot_add_disk = raid5_add_disk, 5887 .hot_remove_disk= raid5_remove_disk, 5888 .spare_active = raid5_spare_active, 5889 .sync_request = sync_request, 5890 .resize = raid5_resize, 5891 .size = raid5_size, 5892 .check_reshape = raid5_check_reshape, 5893 .start_reshape = raid5_start_reshape, 5894 .finish_reshape = raid5_finish_reshape, 5895 .quiesce = raid5_quiesce, 5896 .takeover = raid4_takeover, 5897 }; 5898 5899 static int __init raid5_init(void) 5900 { 5901 register_md_personality(&raid6_personality); 5902 register_md_personality(&raid5_personality); 5903 register_md_personality(&raid4_personality); 5904 return 0; 5905 } 5906 5907 static void raid5_exit(void) 5908 { 5909 unregister_md_personality(&raid6_personality); 5910 unregister_md_personality(&raid5_personality); 5911 unregister_md_personality(&raid4_personality); 5912 } 5913 5914 module_init(raid5_init); 5915 module_exit(raid5_exit); 5916 MODULE_LICENSE("GPL"); 5917 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD"); 5918 MODULE_ALIAS("md-personality-4"); /* RAID5 */ 5919 MODULE_ALIAS("md-raid5"); 5920 MODULE_ALIAS("md-raid4"); 5921 MODULE_ALIAS("md-level-5"); 5922 MODULE_ALIAS("md-level-4"); 5923 MODULE_ALIAS("md-personality-8"); /* RAID6 */ 5924 MODULE_ALIAS("md-raid6"); 5925 MODULE_ALIAS("md-level-6"); 5926 5927 /* This used to be two separate modules, they were: */ 5928 MODULE_ALIAS("raid5"); 5929 MODULE_ALIAS("raid6"); 5930