1 /* 2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the GPL. 6 */ 7 8 #include "dm.h" 9 #include "dm-uevent.h" 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/mutex.h> 14 #include <linux/moduleparam.h> 15 #include <linux/blkpg.h> 16 #include <linux/bio.h> 17 #include <linux/buffer_head.h> 18 #include <linux/mempool.h> 19 #include <linux/slab.h> 20 #include <linux/idr.h> 21 #include <linux/hdreg.h> 22 23 #include <trace/events/block.h> 24 25 #define DM_MSG_PREFIX "core" 26 27 static const char *_name = DM_NAME; 28 29 static unsigned int major = 0; 30 static unsigned int _major = 0; 31 32 static DEFINE_SPINLOCK(_minor_lock); 33 /* 34 * For bio-based dm. 35 * One of these is allocated per bio. 36 */ 37 struct dm_io { 38 struct mapped_device *md; 39 int error; 40 atomic_t io_count; 41 struct bio *bio; 42 unsigned long start_time; 43 }; 44 45 /* 46 * For bio-based dm. 47 * One of these is allocated per target within a bio. Hopefully 48 * this will be simplified out one day. 49 */ 50 struct dm_target_io { 51 struct dm_io *io; 52 struct dm_target *ti; 53 union map_info info; 54 }; 55 56 /* 57 * For request-based dm. 58 * One of these is allocated per request. 59 */ 60 struct dm_rq_target_io { 61 struct mapped_device *md; 62 struct dm_target *ti; 63 struct request *orig, clone; 64 int error; 65 union map_info info; 66 }; 67 68 /* 69 * For request-based dm. 70 * One of these is allocated per bio. 71 */ 72 struct dm_rq_clone_bio_info { 73 struct bio *orig; 74 struct request *rq; 75 }; 76 77 union map_info *dm_get_mapinfo(struct bio *bio) 78 { 79 if (bio && bio->bi_private) 80 return &((struct dm_target_io *)bio->bi_private)->info; 81 return NULL; 82 } 83 84 #define MINOR_ALLOCED ((void *)-1) 85 86 /* 87 * Bits for the md->flags field. 88 */ 89 #define DMF_BLOCK_IO_FOR_SUSPEND 0 90 #define DMF_SUSPENDED 1 91 #define DMF_FROZEN 2 92 #define DMF_FREEING 3 93 #define DMF_DELETING 4 94 #define DMF_NOFLUSH_SUSPENDING 5 95 #define DMF_QUEUE_IO_TO_THREAD 6 96 97 /* 98 * Work processed by per-device workqueue. 99 */ 100 struct mapped_device { 101 struct rw_semaphore io_lock; 102 struct mutex suspend_lock; 103 rwlock_t map_lock; 104 atomic_t holders; 105 atomic_t open_count; 106 107 unsigned long flags; 108 109 struct request_queue *queue; 110 struct gendisk *disk; 111 char name[16]; 112 113 void *interface_ptr; 114 115 /* 116 * A list of ios that arrived while we were suspended. 117 */ 118 atomic_t pending; 119 wait_queue_head_t wait; 120 struct work_struct work; 121 struct bio_list deferred; 122 spinlock_t deferred_lock; 123 124 /* 125 * An error from the barrier request currently being processed. 126 */ 127 int barrier_error; 128 129 /* 130 * Processing queue (flush/barriers) 131 */ 132 struct workqueue_struct *wq; 133 134 /* 135 * The current mapping. 136 */ 137 struct dm_table *map; 138 139 /* 140 * io objects are allocated from here. 141 */ 142 mempool_t *io_pool; 143 mempool_t *tio_pool; 144 145 struct bio_set *bs; 146 147 /* 148 * Event handling. 149 */ 150 atomic_t event_nr; 151 wait_queue_head_t eventq; 152 atomic_t uevent_seq; 153 struct list_head uevent_list; 154 spinlock_t uevent_lock; /* Protect access to uevent_list */ 155 156 /* 157 * freeze/thaw support require holding onto a super block 158 */ 159 struct super_block *frozen_sb; 160 struct block_device *bdev; 161 162 /* forced geometry settings */ 163 struct hd_geometry geometry; 164 165 /* sysfs handle */ 166 struct kobject kobj; 167 }; 168 169 #define MIN_IOS 256 170 static struct kmem_cache *_io_cache; 171 static struct kmem_cache *_tio_cache; 172 static struct kmem_cache *_rq_tio_cache; 173 static struct kmem_cache *_rq_bio_info_cache; 174 175 static int __init local_init(void) 176 { 177 int r = -ENOMEM; 178 179 /* allocate a slab for the dm_ios */ 180 _io_cache = KMEM_CACHE(dm_io, 0); 181 if (!_io_cache) 182 return r; 183 184 /* allocate a slab for the target ios */ 185 _tio_cache = KMEM_CACHE(dm_target_io, 0); 186 if (!_tio_cache) 187 goto out_free_io_cache; 188 189 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0); 190 if (!_rq_tio_cache) 191 goto out_free_tio_cache; 192 193 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0); 194 if (!_rq_bio_info_cache) 195 goto out_free_rq_tio_cache; 196 197 r = dm_uevent_init(); 198 if (r) 199 goto out_free_rq_bio_info_cache; 200 201 _major = major; 202 r = register_blkdev(_major, _name); 203 if (r < 0) 204 goto out_uevent_exit; 205 206 if (!_major) 207 _major = r; 208 209 return 0; 210 211 out_uevent_exit: 212 dm_uevent_exit(); 213 out_free_rq_bio_info_cache: 214 kmem_cache_destroy(_rq_bio_info_cache); 215 out_free_rq_tio_cache: 216 kmem_cache_destroy(_rq_tio_cache); 217 out_free_tio_cache: 218 kmem_cache_destroy(_tio_cache); 219 out_free_io_cache: 220 kmem_cache_destroy(_io_cache); 221 222 return r; 223 } 224 225 static void local_exit(void) 226 { 227 kmem_cache_destroy(_rq_bio_info_cache); 228 kmem_cache_destroy(_rq_tio_cache); 229 kmem_cache_destroy(_tio_cache); 230 kmem_cache_destroy(_io_cache); 231 unregister_blkdev(_major, _name); 232 dm_uevent_exit(); 233 234 _major = 0; 235 236 DMINFO("cleaned up"); 237 } 238 239 static int (*_inits[])(void) __initdata = { 240 local_init, 241 dm_target_init, 242 dm_linear_init, 243 dm_stripe_init, 244 dm_kcopyd_init, 245 dm_interface_init, 246 }; 247 248 static void (*_exits[])(void) = { 249 local_exit, 250 dm_target_exit, 251 dm_linear_exit, 252 dm_stripe_exit, 253 dm_kcopyd_exit, 254 dm_interface_exit, 255 }; 256 257 static int __init dm_init(void) 258 { 259 const int count = ARRAY_SIZE(_inits); 260 261 int r, i; 262 263 for (i = 0; i < count; i++) { 264 r = _inits[i](); 265 if (r) 266 goto bad; 267 } 268 269 return 0; 270 271 bad: 272 while (i--) 273 _exits[i](); 274 275 return r; 276 } 277 278 static void __exit dm_exit(void) 279 { 280 int i = ARRAY_SIZE(_exits); 281 282 while (i--) 283 _exits[i](); 284 } 285 286 /* 287 * Block device functions 288 */ 289 static int dm_blk_open(struct block_device *bdev, fmode_t mode) 290 { 291 struct mapped_device *md; 292 293 spin_lock(&_minor_lock); 294 295 md = bdev->bd_disk->private_data; 296 if (!md) 297 goto out; 298 299 if (test_bit(DMF_FREEING, &md->flags) || 300 test_bit(DMF_DELETING, &md->flags)) { 301 md = NULL; 302 goto out; 303 } 304 305 dm_get(md); 306 atomic_inc(&md->open_count); 307 308 out: 309 spin_unlock(&_minor_lock); 310 311 return md ? 0 : -ENXIO; 312 } 313 314 static int dm_blk_close(struct gendisk *disk, fmode_t mode) 315 { 316 struct mapped_device *md = disk->private_data; 317 atomic_dec(&md->open_count); 318 dm_put(md); 319 return 0; 320 } 321 322 int dm_open_count(struct mapped_device *md) 323 { 324 return atomic_read(&md->open_count); 325 } 326 327 /* 328 * Guarantees nothing is using the device before it's deleted. 329 */ 330 int dm_lock_for_deletion(struct mapped_device *md) 331 { 332 int r = 0; 333 334 spin_lock(&_minor_lock); 335 336 if (dm_open_count(md)) 337 r = -EBUSY; 338 else 339 set_bit(DMF_DELETING, &md->flags); 340 341 spin_unlock(&_minor_lock); 342 343 return r; 344 } 345 346 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) 347 { 348 struct mapped_device *md = bdev->bd_disk->private_data; 349 350 return dm_get_geometry(md, geo); 351 } 352 353 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, 354 unsigned int cmd, unsigned long arg) 355 { 356 struct mapped_device *md = bdev->bd_disk->private_data; 357 struct dm_table *map = dm_get_table(md); 358 struct dm_target *tgt; 359 int r = -ENOTTY; 360 361 if (!map || !dm_table_get_size(map)) 362 goto out; 363 364 /* We only support devices that have a single target */ 365 if (dm_table_get_num_targets(map) != 1) 366 goto out; 367 368 tgt = dm_table_get_target(map, 0); 369 370 if (dm_suspended(md)) { 371 r = -EAGAIN; 372 goto out; 373 } 374 375 if (tgt->type->ioctl) 376 r = tgt->type->ioctl(tgt, cmd, arg); 377 378 out: 379 dm_table_put(map); 380 381 return r; 382 } 383 384 static struct dm_io *alloc_io(struct mapped_device *md) 385 { 386 return mempool_alloc(md->io_pool, GFP_NOIO); 387 } 388 389 static void free_io(struct mapped_device *md, struct dm_io *io) 390 { 391 mempool_free(io, md->io_pool); 392 } 393 394 static struct dm_target_io *alloc_tio(struct mapped_device *md) 395 { 396 return mempool_alloc(md->tio_pool, GFP_NOIO); 397 } 398 399 static void free_tio(struct mapped_device *md, struct dm_target_io *tio) 400 { 401 mempool_free(tio, md->tio_pool); 402 } 403 404 static void start_io_acct(struct dm_io *io) 405 { 406 struct mapped_device *md = io->md; 407 int cpu; 408 409 io->start_time = jiffies; 410 411 cpu = part_stat_lock(); 412 part_round_stats(cpu, &dm_disk(md)->part0); 413 part_stat_unlock(); 414 dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending); 415 } 416 417 static void end_io_acct(struct dm_io *io) 418 { 419 struct mapped_device *md = io->md; 420 struct bio *bio = io->bio; 421 unsigned long duration = jiffies - io->start_time; 422 int pending, cpu; 423 int rw = bio_data_dir(bio); 424 425 cpu = part_stat_lock(); 426 part_round_stats(cpu, &dm_disk(md)->part0); 427 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration); 428 part_stat_unlock(); 429 430 /* 431 * After this is decremented the bio must not be touched if it is 432 * a barrier. 433 */ 434 dm_disk(md)->part0.in_flight = pending = 435 atomic_dec_return(&md->pending); 436 437 /* nudge anyone waiting on suspend queue */ 438 if (!pending) 439 wake_up(&md->wait); 440 } 441 442 /* 443 * Add the bio to the list of deferred io. 444 */ 445 static void queue_io(struct mapped_device *md, struct bio *bio) 446 { 447 down_write(&md->io_lock); 448 449 spin_lock_irq(&md->deferred_lock); 450 bio_list_add(&md->deferred, bio); 451 spin_unlock_irq(&md->deferred_lock); 452 453 if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) 454 queue_work(md->wq, &md->work); 455 456 up_write(&md->io_lock); 457 } 458 459 /* 460 * Everyone (including functions in this file), should use this 461 * function to access the md->map field, and make sure they call 462 * dm_table_put() when finished. 463 */ 464 struct dm_table *dm_get_table(struct mapped_device *md) 465 { 466 struct dm_table *t; 467 468 read_lock(&md->map_lock); 469 t = md->map; 470 if (t) 471 dm_table_get(t); 472 read_unlock(&md->map_lock); 473 474 return t; 475 } 476 477 /* 478 * Get the geometry associated with a dm device 479 */ 480 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo) 481 { 482 *geo = md->geometry; 483 484 return 0; 485 } 486 487 /* 488 * Set the geometry of a device. 489 */ 490 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo) 491 { 492 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors; 493 494 if (geo->start > sz) { 495 DMWARN("Start sector is beyond the geometry limits."); 496 return -EINVAL; 497 } 498 499 md->geometry = *geo; 500 501 return 0; 502 } 503 504 /*----------------------------------------------------------------- 505 * CRUD START: 506 * A more elegant soln is in the works that uses the queue 507 * merge fn, unfortunately there are a couple of changes to 508 * the block layer that I want to make for this. So in the 509 * interests of getting something for people to use I give 510 * you this clearly demarcated crap. 511 *---------------------------------------------------------------*/ 512 513 static int __noflush_suspending(struct mapped_device *md) 514 { 515 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 516 } 517 518 /* 519 * Decrements the number of outstanding ios that a bio has been 520 * cloned into, completing the original io if necc. 521 */ 522 static void dec_pending(struct dm_io *io, int error) 523 { 524 unsigned long flags; 525 int io_error; 526 struct bio *bio; 527 struct mapped_device *md = io->md; 528 529 /* Push-back supersedes any I/O errors */ 530 if (error && !(io->error > 0 && __noflush_suspending(md))) 531 io->error = error; 532 533 if (atomic_dec_and_test(&io->io_count)) { 534 if (io->error == DM_ENDIO_REQUEUE) { 535 /* 536 * Target requested pushing back the I/O. 537 */ 538 spin_lock_irqsave(&md->deferred_lock, flags); 539 if (__noflush_suspending(md)) 540 bio_list_add_head(&md->deferred, io->bio); 541 else 542 /* noflush suspend was interrupted. */ 543 io->error = -EIO; 544 spin_unlock_irqrestore(&md->deferred_lock, flags); 545 } 546 547 io_error = io->error; 548 bio = io->bio; 549 550 if (bio_barrier(bio)) { 551 /* 552 * There can be just one barrier request so we use 553 * a per-device variable for error reporting. 554 * Note that you can't touch the bio after end_io_acct 555 */ 556 md->barrier_error = io_error; 557 end_io_acct(io); 558 } else { 559 end_io_acct(io); 560 561 if (io_error != DM_ENDIO_REQUEUE) { 562 trace_block_bio_complete(md->queue, bio); 563 564 bio_endio(bio, io_error); 565 } 566 } 567 568 free_io(md, io); 569 } 570 } 571 572 static void clone_endio(struct bio *bio, int error) 573 { 574 int r = 0; 575 struct dm_target_io *tio = bio->bi_private; 576 struct dm_io *io = tio->io; 577 struct mapped_device *md = tio->io->md; 578 dm_endio_fn endio = tio->ti->type->end_io; 579 580 if (!bio_flagged(bio, BIO_UPTODATE) && !error) 581 error = -EIO; 582 583 if (endio) { 584 r = endio(tio->ti, bio, error, &tio->info); 585 if (r < 0 || r == DM_ENDIO_REQUEUE) 586 /* 587 * error and requeue request are handled 588 * in dec_pending(). 589 */ 590 error = r; 591 else if (r == DM_ENDIO_INCOMPLETE) 592 /* The target will handle the io */ 593 return; 594 else if (r) { 595 DMWARN("unimplemented target endio return value: %d", r); 596 BUG(); 597 } 598 } 599 600 /* 601 * Store md for cleanup instead of tio which is about to get freed. 602 */ 603 bio->bi_private = md->bs; 604 605 free_tio(md, tio); 606 bio_put(bio); 607 dec_pending(io, error); 608 } 609 610 static sector_t max_io_len(struct mapped_device *md, 611 sector_t sector, struct dm_target *ti) 612 { 613 sector_t offset = sector - ti->begin; 614 sector_t len = ti->len - offset; 615 616 /* 617 * Does the target need to split even further ? 618 */ 619 if (ti->split_io) { 620 sector_t boundary; 621 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) 622 - offset; 623 if (len > boundary) 624 len = boundary; 625 } 626 627 return len; 628 } 629 630 static void __map_bio(struct dm_target *ti, struct bio *clone, 631 struct dm_target_io *tio) 632 { 633 int r; 634 sector_t sector; 635 struct mapped_device *md; 636 637 /* 638 * Sanity checks. 639 */ 640 BUG_ON(!clone->bi_size); 641 642 clone->bi_end_io = clone_endio; 643 clone->bi_private = tio; 644 645 /* 646 * Map the clone. If r == 0 we don't need to do 647 * anything, the target has assumed ownership of 648 * this io. 649 */ 650 atomic_inc(&tio->io->io_count); 651 sector = clone->bi_sector; 652 r = ti->type->map(ti, clone, &tio->info); 653 if (r == DM_MAPIO_REMAPPED) { 654 /* the bio has been remapped so dispatch it */ 655 656 trace_block_remap(bdev_get_queue(clone->bi_bdev), clone, 657 tio->io->bio->bi_bdev->bd_dev, sector); 658 659 generic_make_request(clone); 660 } else if (r < 0 || r == DM_MAPIO_REQUEUE) { 661 /* error the io and bail out, or requeue it if needed */ 662 md = tio->io->md; 663 dec_pending(tio->io, r); 664 /* 665 * Store bio_set for cleanup. 666 */ 667 clone->bi_private = md->bs; 668 bio_put(clone); 669 free_tio(md, tio); 670 } else if (r) { 671 DMWARN("unimplemented target map return value: %d", r); 672 BUG(); 673 } 674 } 675 676 struct clone_info { 677 struct mapped_device *md; 678 struct dm_table *map; 679 struct bio *bio; 680 struct dm_io *io; 681 sector_t sector; 682 sector_t sector_count; 683 unsigned short idx; 684 }; 685 686 static void dm_bio_destructor(struct bio *bio) 687 { 688 struct bio_set *bs = bio->bi_private; 689 690 bio_free(bio, bs); 691 } 692 693 /* 694 * Creates a little bio that is just does part of a bvec. 695 */ 696 static struct bio *split_bvec(struct bio *bio, sector_t sector, 697 unsigned short idx, unsigned int offset, 698 unsigned int len, struct bio_set *bs) 699 { 700 struct bio *clone; 701 struct bio_vec *bv = bio->bi_io_vec + idx; 702 703 clone = bio_alloc_bioset(GFP_NOIO, 1, bs); 704 clone->bi_destructor = dm_bio_destructor; 705 *clone->bi_io_vec = *bv; 706 707 clone->bi_sector = sector; 708 clone->bi_bdev = bio->bi_bdev; 709 clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER); 710 clone->bi_vcnt = 1; 711 clone->bi_size = to_bytes(len); 712 clone->bi_io_vec->bv_offset = offset; 713 clone->bi_io_vec->bv_len = clone->bi_size; 714 clone->bi_flags |= 1 << BIO_CLONED; 715 716 if (bio_integrity(bio)) { 717 bio_integrity_clone(clone, bio, GFP_NOIO); 718 bio_integrity_trim(clone, 719 bio_sector_offset(bio, idx, offset), len); 720 } 721 722 return clone; 723 } 724 725 /* 726 * Creates a bio that consists of range of complete bvecs. 727 */ 728 static struct bio *clone_bio(struct bio *bio, sector_t sector, 729 unsigned short idx, unsigned short bv_count, 730 unsigned int len, struct bio_set *bs) 731 { 732 struct bio *clone; 733 734 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); 735 __bio_clone(clone, bio); 736 clone->bi_rw &= ~(1 << BIO_RW_BARRIER); 737 clone->bi_destructor = dm_bio_destructor; 738 clone->bi_sector = sector; 739 clone->bi_idx = idx; 740 clone->bi_vcnt = idx + bv_count; 741 clone->bi_size = to_bytes(len); 742 clone->bi_flags &= ~(1 << BIO_SEG_VALID); 743 744 if (bio_integrity(bio)) { 745 bio_integrity_clone(clone, bio, GFP_NOIO); 746 747 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size) 748 bio_integrity_trim(clone, 749 bio_sector_offset(bio, idx, 0), len); 750 } 751 752 return clone; 753 } 754 755 static int __clone_and_map(struct clone_info *ci) 756 { 757 struct bio *clone, *bio = ci->bio; 758 struct dm_target *ti; 759 sector_t len = 0, max; 760 struct dm_target_io *tio; 761 762 ti = dm_table_find_target(ci->map, ci->sector); 763 if (!dm_target_is_valid(ti)) 764 return -EIO; 765 766 max = max_io_len(ci->md, ci->sector, ti); 767 768 /* 769 * Allocate a target io object. 770 */ 771 tio = alloc_tio(ci->md); 772 tio->io = ci->io; 773 tio->ti = ti; 774 memset(&tio->info, 0, sizeof(tio->info)); 775 776 if (ci->sector_count <= max) { 777 /* 778 * Optimise for the simple case where we can do all of 779 * the remaining io with a single clone. 780 */ 781 clone = clone_bio(bio, ci->sector, ci->idx, 782 bio->bi_vcnt - ci->idx, ci->sector_count, 783 ci->md->bs); 784 __map_bio(ti, clone, tio); 785 ci->sector_count = 0; 786 787 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { 788 /* 789 * There are some bvecs that don't span targets. 790 * Do as many of these as possible. 791 */ 792 int i; 793 sector_t remaining = max; 794 sector_t bv_len; 795 796 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { 797 bv_len = to_sector(bio->bi_io_vec[i].bv_len); 798 799 if (bv_len > remaining) 800 break; 801 802 remaining -= bv_len; 803 len += bv_len; 804 } 805 806 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len, 807 ci->md->bs); 808 __map_bio(ti, clone, tio); 809 810 ci->sector += len; 811 ci->sector_count -= len; 812 ci->idx = i; 813 814 } else { 815 /* 816 * Handle a bvec that must be split between two or more targets. 817 */ 818 struct bio_vec *bv = bio->bi_io_vec + ci->idx; 819 sector_t remaining = to_sector(bv->bv_len); 820 unsigned int offset = 0; 821 822 do { 823 if (offset) { 824 ti = dm_table_find_target(ci->map, ci->sector); 825 if (!dm_target_is_valid(ti)) 826 return -EIO; 827 828 max = max_io_len(ci->md, ci->sector, ti); 829 830 tio = alloc_tio(ci->md); 831 tio->io = ci->io; 832 tio->ti = ti; 833 memset(&tio->info, 0, sizeof(tio->info)); 834 } 835 836 len = min(remaining, max); 837 838 clone = split_bvec(bio, ci->sector, ci->idx, 839 bv->bv_offset + offset, len, 840 ci->md->bs); 841 842 __map_bio(ti, clone, tio); 843 844 ci->sector += len; 845 ci->sector_count -= len; 846 offset += to_bytes(len); 847 } while (remaining -= len); 848 849 ci->idx++; 850 } 851 852 return 0; 853 } 854 855 /* 856 * Split the bio into several clones and submit it to targets. 857 */ 858 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) 859 { 860 struct clone_info ci; 861 int error = 0; 862 863 ci.map = dm_get_table(md); 864 if (unlikely(!ci.map)) { 865 if (!bio_barrier(bio)) 866 bio_io_error(bio); 867 else 868 md->barrier_error = -EIO; 869 return; 870 } 871 872 ci.md = md; 873 ci.bio = bio; 874 ci.io = alloc_io(md); 875 ci.io->error = 0; 876 atomic_set(&ci.io->io_count, 1); 877 ci.io->bio = bio; 878 ci.io->md = md; 879 ci.sector = bio->bi_sector; 880 ci.sector_count = bio_sectors(bio); 881 ci.idx = bio->bi_idx; 882 883 start_io_acct(ci.io); 884 while (ci.sector_count && !error) 885 error = __clone_and_map(&ci); 886 887 /* drop the extra reference count */ 888 dec_pending(ci.io, error); 889 dm_table_put(ci.map); 890 } 891 /*----------------------------------------------------------------- 892 * CRUD END 893 *---------------------------------------------------------------*/ 894 895 static int dm_merge_bvec(struct request_queue *q, 896 struct bvec_merge_data *bvm, 897 struct bio_vec *biovec) 898 { 899 struct mapped_device *md = q->queuedata; 900 struct dm_table *map = dm_get_table(md); 901 struct dm_target *ti; 902 sector_t max_sectors; 903 int max_size = 0; 904 905 if (unlikely(!map)) 906 goto out; 907 908 ti = dm_table_find_target(map, bvm->bi_sector); 909 if (!dm_target_is_valid(ti)) 910 goto out_table; 911 912 /* 913 * Find maximum amount of I/O that won't need splitting 914 */ 915 max_sectors = min(max_io_len(md, bvm->bi_sector, ti), 916 (sector_t) BIO_MAX_SECTORS); 917 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; 918 if (max_size < 0) 919 max_size = 0; 920 921 /* 922 * merge_bvec_fn() returns number of bytes 923 * it can accept at this offset 924 * max is precomputed maximal io size 925 */ 926 if (max_size && ti->type->merge) 927 max_size = ti->type->merge(ti, bvm, biovec, max_size); 928 /* 929 * If the target doesn't support merge method and some of the devices 930 * provided their merge_bvec method (we know this by looking at 931 * queue_max_hw_sectors), then we can't allow bios with multiple vector 932 * entries. So always set max_size to 0, and the code below allows 933 * just one page. 934 */ 935 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) 936 937 max_size = 0; 938 939 out_table: 940 dm_table_put(map); 941 942 out: 943 /* 944 * Always allow an entire first page 945 */ 946 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) 947 max_size = biovec->bv_len; 948 949 return max_size; 950 } 951 952 /* 953 * The request function that just remaps the bio built up by 954 * dm_merge_bvec. 955 */ 956 static int dm_request(struct request_queue *q, struct bio *bio) 957 { 958 int rw = bio_data_dir(bio); 959 struct mapped_device *md = q->queuedata; 960 int cpu; 961 962 down_read(&md->io_lock); 963 964 cpu = part_stat_lock(); 965 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]); 966 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio)); 967 part_stat_unlock(); 968 969 /* 970 * If we're suspended or the thread is processing barriers 971 * we have to queue this io for later. 972 */ 973 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) || 974 unlikely(bio_barrier(bio))) { 975 up_read(&md->io_lock); 976 977 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && 978 bio_rw(bio) == READA) { 979 bio_io_error(bio); 980 return 0; 981 } 982 983 queue_io(md, bio); 984 985 return 0; 986 } 987 988 __split_and_process_bio(md, bio); 989 up_read(&md->io_lock); 990 return 0; 991 } 992 993 static void dm_unplug_all(struct request_queue *q) 994 { 995 struct mapped_device *md = q->queuedata; 996 struct dm_table *map = dm_get_table(md); 997 998 if (map) { 999 dm_table_unplug_all(map); 1000 dm_table_put(map); 1001 } 1002 } 1003 1004 static int dm_any_congested(void *congested_data, int bdi_bits) 1005 { 1006 int r = bdi_bits; 1007 struct mapped_device *md = congested_data; 1008 struct dm_table *map; 1009 1010 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { 1011 map = dm_get_table(md); 1012 if (map) { 1013 r = dm_table_any_congested(map, bdi_bits); 1014 dm_table_put(map); 1015 } 1016 } 1017 1018 return r; 1019 } 1020 1021 /*----------------------------------------------------------------- 1022 * An IDR is used to keep track of allocated minor numbers. 1023 *---------------------------------------------------------------*/ 1024 static DEFINE_IDR(_minor_idr); 1025 1026 static void free_minor(int minor) 1027 { 1028 spin_lock(&_minor_lock); 1029 idr_remove(&_minor_idr, minor); 1030 spin_unlock(&_minor_lock); 1031 } 1032 1033 /* 1034 * See if the device with a specific minor # is free. 1035 */ 1036 static int specific_minor(int minor) 1037 { 1038 int r, m; 1039 1040 if (minor >= (1 << MINORBITS)) 1041 return -EINVAL; 1042 1043 r = idr_pre_get(&_minor_idr, GFP_KERNEL); 1044 if (!r) 1045 return -ENOMEM; 1046 1047 spin_lock(&_minor_lock); 1048 1049 if (idr_find(&_minor_idr, minor)) { 1050 r = -EBUSY; 1051 goto out; 1052 } 1053 1054 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); 1055 if (r) 1056 goto out; 1057 1058 if (m != minor) { 1059 idr_remove(&_minor_idr, m); 1060 r = -EBUSY; 1061 goto out; 1062 } 1063 1064 out: 1065 spin_unlock(&_minor_lock); 1066 return r; 1067 } 1068 1069 static int next_free_minor(int *minor) 1070 { 1071 int r, m; 1072 1073 r = idr_pre_get(&_minor_idr, GFP_KERNEL); 1074 if (!r) 1075 return -ENOMEM; 1076 1077 spin_lock(&_minor_lock); 1078 1079 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); 1080 if (r) 1081 goto out; 1082 1083 if (m >= (1 << MINORBITS)) { 1084 idr_remove(&_minor_idr, m); 1085 r = -ENOSPC; 1086 goto out; 1087 } 1088 1089 *minor = m; 1090 1091 out: 1092 spin_unlock(&_minor_lock); 1093 return r; 1094 } 1095 1096 static struct block_device_operations dm_blk_dops; 1097 1098 static void dm_wq_work(struct work_struct *work); 1099 1100 /* 1101 * Allocate and initialise a blank device with a given minor. 1102 */ 1103 static struct mapped_device *alloc_dev(int minor) 1104 { 1105 int r; 1106 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL); 1107 void *old_md; 1108 1109 if (!md) { 1110 DMWARN("unable to allocate device, out of memory."); 1111 return NULL; 1112 } 1113 1114 if (!try_module_get(THIS_MODULE)) 1115 goto bad_module_get; 1116 1117 /* get a minor number for the dev */ 1118 if (minor == DM_ANY_MINOR) 1119 r = next_free_minor(&minor); 1120 else 1121 r = specific_minor(minor); 1122 if (r < 0) 1123 goto bad_minor; 1124 1125 init_rwsem(&md->io_lock); 1126 mutex_init(&md->suspend_lock); 1127 spin_lock_init(&md->deferred_lock); 1128 rwlock_init(&md->map_lock); 1129 atomic_set(&md->holders, 1); 1130 atomic_set(&md->open_count, 0); 1131 atomic_set(&md->event_nr, 0); 1132 atomic_set(&md->uevent_seq, 0); 1133 INIT_LIST_HEAD(&md->uevent_list); 1134 spin_lock_init(&md->uevent_lock); 1135 1136 md->queue = blk_alloc_queue(GFP_KERNEL); 1137 if (!md->queue) 1138 goto bad_queue; 1139 1140 md->queue->queuedata = md; 1141 md->queue->backing_dev_info.congested_fn = dm_any_congested; 1142 md->queue->backing_dev_info.congested_data = md; 1143 blk_queue_make_request(md->queue, dm_request); 1144 blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL); 1145 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); 1146 md->queue->unplug_fn = dm_unplug_all; 1147 blk_queue_merge_bvec(md->queue, dm_merge_bvec); 1148 1149 md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); 1150 if (!md->io_pool) 1151 goto bad_io_pool; 1152 1153 md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); 1154 if (!md->tio_pool) 1155 goto bad_tio_pool; 1156 1157 md->bs = bioset_create(16, 0); 1158 if (!md->bs) 1159 goto bad_no_bioset; 1160 1161 md->disk = alloc_disk(1); 1162 if (!md->disk) 1163 goto bad_disk; 1164 1165 atomic_set(&md->pending, 0); 1166 init_waitqueue_head(&md->wait); 1167 INIT_WORK(&md->work, dm_wq_work); 1168 init_waitqueue_head(&md->eventq); 1169 1170 md->disk->major = _major; 1171 md->disk->first_minor = minor; 1172 md->disk->fops = &dm_blk_dops; 1173 md->disk->queue = md->queue; 1174 md->disk->private_data = md; 1175 sprintf(md->disk->disk_name, "dm-%d", minor); 1176 add_disk(md->disk); 1177 format_dev_t(md->name, MKDEV(_major, minor)); 1178 1179 md->wq = create_singlethread_workqueue("kdmflush"); 1180 if (!md->wq) 1181 goto bad_thread; 1182 1183 /* Populate the mapping, nobody knows we exist yet */ 1184 spin_lock(&_minor_lock); 1185 old_md = idr_replace(&_minor_idr, md, minor); 1186 spin_unlock(&_minor_lock); 1187 1188 BUG_ON(old_md != MINOR_ALLOCED); 1189 1190 return md; 1191 1192 bad_thread: 1193 put_disk(md->disk); 1194 bad_disk: 1195 bioset_free(md->bs); 1196 bad_no_bioset: 1197 mempool_destroy(md->tio_pool); 1198 bad_tio_pool: 1199 mempool_destroy(md->io_pool); 1200 bad_io_pool: 1201 blk_cleanup_queue(md->queue); 1202 bad_queue: 1203 free_minor(minor); 1204 bad_minor: 1205 module_put(THIS_MODULE); 1206 bad_module_get: 1207 kfree(md); 1208 return NULL; 1209 } 1210 1211 static void unlock_fs(struct mapped_device *md); 1212 1213 static void free_dev(struct mapped_device *md) 1214 { 1215 int minor = MINOR(disk_devt(md->disk)); 1216 1217 if (md->bdev) { 1218 unlock_fs(md); 1219 bdput(md->bdev); 1220 } 1221 destroy_workqueue(md->wq); 1222 mempool_destroy(md->tio_pool); 1223 mempool_destroy(md->io_pool); 1224 bioset_free(md->bs); 1225 blk_integrity_unregister(md->disk); 1226 del_gendisk(md->disk); 1227 free_minor(minor); 1228 1229 spin_lock(&_minor_lock); 1230 md->disk->private_data = NULL; 1231 spin_unlock(&_minor_lock); 1232 1233 put_disk(md->disk); 1234 blk_cleanup_queue(md->queue); 1235 module_put(THIS_MODULE); 1236 kfree(md); 1237 } 1238 1239 /* 1240 * Bind a table to the device. 1241 */ 1242 static void event_callback(void *context) 1243 { 1244 unsigned long flags; 1245 LIST_HEAD(uevents); 1246 struct mapped_device *md = (struct mapped_device *) context; 1247 1248 spin_lock_irqsave(&md->uevent_lock, flags); 1249 list_splice_init(&md->uevent_list, &uevents); 1250 spin_unlock_irqrestore(&md->uevent_lock, flags); 1251 1252 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); 1253 1254 atomic_inc(&md->event_nr); 1255 wake_up(&md->eventq); 1256 } 1257 1258 static void __set_size(struct mapped_device *md, sector_t size) 1259 { 1260 set_capacity(md->disk, size); 1261 1262 mutex_lock(&md->bdev->bd_inode->i_mutex); 1263 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); 1264 mutex_unlock(&md->bdev->bd_inode->i_mutex); 1265 } 1266 1267 static int __bind(struct mapped_device *md, struct dm_table *t) 1268 { 1269 struct request_queue *q = md->queue; 1270 sector_t size; 1271 1272 size = dm_table_get_size(t); 1273 1274 /* 1275 * Wipe any geometry if the size of the table changed. 1276 */ 1277 if (size != get_capacity(md->disk)) 1278 memset(&md->geometry, 0, sizeof(md->geometry)); 1279 1280 if (md->bdev) 1281 __set_size(md, size); 1282 1283 if (!size) { 1284 dm_table_destroy(t); 1285 return 0; 1286 } 1287 1288 dm_table_event_callback(t, event_callback, md); 1289 1290 write_lock(&md->map_lock); 1291 md->map = t; 1292 dm_table_set_restrictions(t, q); 1293 write_unlock(&md->map_lock); 1294 1295 return 0; 1296 } 1297 1298 static void __unbind(struct mapped_device *md) 1299 { 1300 struct dm_table *map = md->map; 1301 1302 if (!map) 1303 return; 1304 1305 dm_table_event_callback(map, NULL, NULL); 1306 write_lock(&md->map_lock); 1307 md->map = NULL; 1308 write_unlock(&md->map_lock); 1309 dm_table_destroy(map); 1310 } 1311 1312 /* 1313 * Constructor for a new device. 1314 */ 1315 int dm_create(int minor, struct mapped_device **result) 1316 { 1317 struct mapped_device *md; 1318 1319 md = alloc_dev(minor); 1320 if (!md) 1321 return -ENXIO; 1322 1323 dm_sysfs_init(md); 1324 1325 *result = md; 1326 return 0; 1327 } 1328 1329 static struct mapped_device *dm_find_md(dev_t dev) 1330 { 1331 struct mapped_device *md; 1332 unsigned minor = MINOR(dev); 1333 1334 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) 1335 return NULL; 1336 1337 spin_lock(&_minor_lock); 1338 1339 md = idr_find(&_minor_idr, minor); 1340 if (md && (md == MINOR_ALLOCED || 1341 (MINOR(disk_devt(dm_disk(md))) != minor) || 1342 test_bit(DMF_FREEING, &md->flags))) { 1343 md = NULL; 1344 goto out; 1345 } 1346 1347 out: 1348 spin_unlock(&_minor_lock); 1349 1350 return md; 1351 } 1352 1353 struct mapped_device *dm_get_md(dev_t dev) 1354 { 1355 struct mapped_device *md = dm_find_md(dev); 1356 1357 if (md) 1358 dm_get(md); 1359 1360 return md; 1361 } 1362 1363 void *dm_get_mdptr(struct mapped_device *md) 1364 { 1365 return md->interface_ptr; 1366 } 1367 1368 void dm_set_mdptr(struct mapped_device *md, void *ptr) 1369 { 1370 md->interface_ptr = ptr; 1371 } 1372 1373 void dm_get(struct mapped_device *md) 1374 { 1375 atomic_inc(&md->holders); 1376 } 1377 1378 const char *dm_device_name(struct mapped_device *md) 1379 { 1380 return md->name; 1381 } 1382 EXPORT_SYMBOL_GPL(dm_device_name); 1383 1384 void dm_put(struct mapped_device *md) 1385 { 1386 struct dm_table *map; 1387 1388 BUG_ON(test_bit(DMF_FREEING, &md->flags)); 1389 1390 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) { 1391 map = dm_get_table(md); 1392 idr_replace(&_minor_idr, MINOR_ALLOCED, 1393 MINOR(disk_devt(dm_disk(md)))); 1394 set_bit(DMF_FREEING, &md->flags); 1395 spin_unlock(&_minor_lock); 1396 if (!dm_suspended(md)) { 1397 dm_table_presuspend_targets(map); 1398 dm_table_postsuspend_targets(map); 1399 } 1400 dm_sysfs_exit(md); 1401 dm_table_put(map); 1402 __unbind(md); 1403 free_dev(md); 1404 } 1405 } 1406 EXPORT_SYMBOL_GPL(dm_put); 1407 1408 static int dm_wait_for_completion(struct mapped_device *md, int interruptible) 1409 { 1410 int r = 0; 1411 DECLARE_WAITQUEUE(wait, current); 1412 1413 dm_unplug_all(md->queue); 1414 1415 add_wait_queue(&md->wait, &wait); 1416 1417 while (1) { 1418 set_current_state(interruptible); 1419 1420 smp_mb(); 1421 if (!atomic_read(&md->pending)) 1422 break; 1423 1424 if (interruptible == TASK_INTERRUPTIBLE && 1425 signal_pending(current)) { 1426 r = -EINTR; 1427 break; 1428 } 1429 1430 io_schedule(); 1431 } 1432 set_current_state(TASK_RUNNING); 1433 1434 remove_wait_queue(&md->wait, &wait); 1435 1436 return r; 1437 } 1438 1439 static int dm_flush(struct mapped_device *md) 1440 { 1441 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); 1442 return 0; 1443 } 1444 1445 static void process_barrier(struct mapped_device *md, struct bio *bio) 1446 { 1447 int error = dm_flush(md); 1448 1449 if (unlikely(error)) { 1450 bio_endio(bio, error); 1451 return; 1452 } 1453 if (bio_empty_barrier(bio)) { 1454 bio_endio(bio, 0); 1455 return; 1456 } 1457 1458 __split_and_process_bio(md, bio); 1459 1460 error = dm_flush(md); 1461 1462 if (!error && md->barrier_error) 1463 error = md->barrier_error; 1464 1465 if (md->barrier_error != DM_ENDIO_REQUEUE) 1466 bio_endio(bio, error); 1467 } 1468 1469 /* 1470 * Process the deferred bios 1471 */ 1472 static void dm_wq_work(struct work_struct *work) 1473 { 1474 struct mapped_device *md = container_of(work, struct mapped_device, 1475 work); 1476 struct bio *c; 1477 1478 down_write(&md->io_lock); 1479 1480 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { 1481 spin_lock_irq(&md->deferred_lock); 1482 c = bio_list_pop(&md->deferred); 1483 spin_unlock_irq(&md->deferred_lock); 1484 1485 if (!c) { 1486 clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags); 1487 break; 1488 } 1489 1490 up_write(&md->io_lock); 1491 1492 if (bio_barrier(c)) 1493 process_barrier(md, c); 1494 else 1495 __split_and_process_bio(md, c); 1496 1497 down_write(&md->io_lock); 1498 } 1499 1500 up_write(&md->io_lock); 1501 } 1502 1503 static void dm_queue_flush(struct mapped_device *md) 1504 { 1505 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); 1506 smp_mb__after_clear_bit(); 1507 queue_work(md->wq, &md->work); 1508 } 1509 1510 /* 1511 * Swap in a new table (destroying old one). 1512 */ 1513 int dm_swap_table(struct mapped_device *md, struct dm_table *table) 1514 { 1515 int r = -EINVAL; 1516 1517 mutex_lock(&md->suspend_lock); 1518 1519 /* device must be suspended */ 1520 if (!dm_suspended(md)) 1521 goto out; 1522 1523 /* without bdev, the device size cannot be changed */ 1524 if (!md->bdev) 1525 if (get_capacity(md->disk) != dm_table_get_size(table)) 1526 goto out; 1527 1528 __unbind(md); 1529 r = __bind(md, table); 1530 1531 out: 1532 mutex_unlock(&md->suspend_lock); 1533 return r; 1534 } 1535 1536 /* 1537 * Functions to lock and unlock any filesystem running on the 1538 * device. 1539 */ 1540 static int lock_fs(struct mapped_device *md) 1541 { 1542 int r; 1543 1544 WARN_ON(md->frozen_sb); 1545 1546 md->frozen_sb = freeze_bdev(md->bdev); 1547 if (IS_ERR(md->frozen_sb)) { 1548 r = PTR_ERR(md->frozen_sb); 1549 md->frozen_sb = NULL; 1550 return r; 1551 } 1552 1553 set_bit(DMF_FROZEN, &md->flags); 1554 1555 /* don't bdput right now, we don't want the bdev 1556 * to go away while it is locked. 1557 */ 1558 return 0; 1559 } 1560 1561 static void unlock_fs(struct mapped_device *md) 1562 { 1563 if (!test_bit(DMF_FROZEN, &md->flags)) 1564 return; 1565 1566 thaw_bdev(md->bdev, md->frozen_sb); 1567 md->frozen_sb = NULL; 1568 clear_bit(DMF_FROZEN, &md->flags); 1569 } 1570 1571 /* 1572 * We need to be able to change a mapping table under a mounted 1573 * filesystem. For example we might want to move some data in 1574 * the background. Before the table can be swapped with 1575 * dm_bind_table, dm_suspend must be called to flush any in 1576 * flight bios and ensure that any further io gets deferred. 1577 */ 1578 int dm_suspend(struct mapped_device *md, unsigned suspend_flags) 1579 { 1580 struct dm_table *map = NULL; 1581 int r = 0; 1582 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; 1583 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; 1584 1585 mutex_lock(&md->suspend_lock); 1586 1587 if (dm_suspended(md)) { 1588 r = -EINVAL; 1589 goto out_unlock; 1590 } 1591 1592 map = dm_get_table(md); 1593 1594 /* 1595 * DMF_NOFLUSH_SUSPENDING must be set before presuspend. 1596 * This flag is cleared before dm_suspend returns. 1597 */ 1598 if (noflush) 1599 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 1600 1601 /* This does not get reverted if there's an error later. */ 1602 dm_table_presuspend_targets(map); 1603 1604 /* bdget() can stall if the pending I/Os are not flushed */ 1605 if (!noflush) { 1606 md->bdev = bdget_disk(md->disk, 0); 1607 if (!md->bdev) { 1608 DMWARN("bdget failed in dm_suspend"); 1609 r = -ENOMEM; 1610 goto out; 1611 } 1612 1613 /* 1614 * Flush I/O to the device. noflush supersedes do_lockfs, 1615 * because lock_fs() needs to flush I/Os. 1616 */ 1617 if (do_lockfs) { 1618 r = lock_fs(md); 1619 if (r) 1620 goto out; 1621 } 1622 } 1623 1624 /* 1625 * Here we must make sure that no processes are submitting requests 1626 * to target drivers i.e. no one may be executing 1627 * __split_and_process_bio. This is called from dm_request and 1628 * dm_wq_work. 1629 * 1630 * To get all processes out of __split_and_process_bio in dm_request, 1631 * we take the write lock. To prevent any process from reentering 1632 * __split_and_process_bio from dm_request, we set 1633 * DMF_QUEUE_IO_TO_THREAD. 1634 * 1635 * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND 1636 * and call flush_workqueue(md->wq). flush_workqueue will wait until 1637 * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any 1638 * further calls to __split_and_process_bio from dm_wq_work. 1639 */ 1640 down_write(&md->io_lock); 1641 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); 1642 set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags); 1643 up_write(&md->io_lock); 1644 1645 flush_workqueue(md->wq); 1646 1647 /* 1648 * At this point no more requests are entering target request routines. 1649 * We call dm_wait_for_completion to wait for all existing requests 1650 * to finish. 1651 */ 1652 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE); 1653 1654 down_write(&md->io_lock); 1655 if (noflush) 1656 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 1657 up_write(&md->io_lock); 1658 1659 /* were we interrupted ? */ 1660 if (r < 0) { 1661 dm_queue_flush(md); 1662 1663 unlock_fs(md); 1664 goto out; /* pushback list is already flushed, so skip flush */ 1665 } 1666 1667 /* 1668 * If dm_wait_for_completion returned 0, the device is completely 1669 * quiescent now. There is no request-processing activity. All new 1670 * requests are being added to md->deferred list. 1671 */ 1672 1673 dm_table_postsuspend_targets(map); 1674 1675 set_bit(DMF_SUSPENDED, &md->flags); 1676 1677 out: 1678 if (r && md->bdev) { 1679 bdput(md->bdev); 1680 md->bdev = NULL; 1681 } 1682 1683 dm_table_put(map); 1684 1685 out_unlock: 1686 mutex_unlock(&md->suspend_lock); 1687 return r; 1688 } 1689 1690 int dm_resume(struct mapped_device *md) 1691 { 1692 int r = -EINVAL; 1693 struct dm_table *map = NULL; 1694 1695 mutex_lock(&md->suspend_lock); 1696 if (!dm_suspended(md)) 1697 goto out; 1698 1699 map = dm_get_table(md); 1700 if (!map || !dm_table_get_size(map)) 1701 goto out; 1702 1703 r = dm_table_resume_targets(map); 1704 if (r) 1705 goto out; 1706 1707 dm_queue_flush(md); 1708 1709 unlock_fs(md); 1710 1711 if (md->bdev) { 1712 bdput(md->bdev); 1713 md->bdev = NULL; 1714 } 1715 1716 clear_bit(DMF_SUSPENDED, &md->flags); 1717 1718 dm_table_unplug_all(map); 1719 1720 dm_kobject_uevent(md); 1721 1722 r = 0; 1723 1724 out: 1725 dm_table_put(map); 1726 mutex_unlock(&md->suspend_lock); 1727 1728 return r; 1729 } 1730 1731 /*----------------------------------------------------------------- 1732 * Event notification. 1733 *---------------------------------------------------------------*/ 1734 void dm_kobject_uevent(struct mapped_device *md) 1735 { 1736 kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE); 1737 } 1738 1739 uint32_t dm_next_uevent_seq(struct mapped_device *md) 1740 { 1741 return atomic_add_return(1, &md->uevent_seq); 1742 } 1743 1744 uint32_t dm_get_event_nr(struct mapped_device *md) 1745 { 1746 return atomic_read(&md->event_nr); 1747 } 1748 1749 int dm_wait_event(struct mapped_device *md, int event_nr) 1750 { 1751 return wait_event_interruptible(md->eventq, 1752 (event_nr != atomic_read(&md->event_nr))); 1753 } 1754 1755 void dm_uevent_add(struct mapped_device *md, struct list_head *elist) 1756 { 1757 unsigned long flags; 1758 1759 spin_lock_irqsave(&md->uevent_lock, flags); 1760 list_add(elist, &md->uevent_list); 1761 spin_unlock_irqrestore(&md->uevent_lock, flags); 1762 } 1763 1764 /* 1765 * The gendisk is only valid as long as you have a reference 1766 * count on 'md'. 1767 */ 1768 struct gendisk *dm_disk(struct mapped_device *md) 1769 { 1770 return md->disk; 1771 } 1772 1773 struct kobject *dm_kobject(struct mapped_device *md) 1774 { 1775 return &md->kobj; 1776 } 1777 1778 /* 1779 * struct mapped_device should not be exported outside of dm.c 1780 * so use this check to verify that kobj is part of md structure 1781 */ 1782 struct mapped_device *dm_get_from_kobject(struct kobject *kobj) 1783 { 1784 struct mapped_device *md; 1785 1786 md = container_of(kobj, struct mapped_device, kobj); 1787 if (&md->kobj != kobj) 1788 return NULL; 1789 1790 if (test_bit(DMF_FREEING, &md->flags) || 1791 test_bit(DMF_DELETING, &md->flags)) 1792 return NULL; 1793 1794 dm_get(md); 1795 return md; 1796 } 1797 1798 int dm_suspended(struct mapped_device *md) 1799 { 1800 return test_bit(DMF_SUSPENDED, &md->flags); 1801 } 1802 1803 int dm_noflush_suspending(struct dm_target *ti) 1804 { 1805 struct mapped_device *md = dm_table_get_md(ti->table); 1806 int r = __noflush_suspending(md); 1807 1808 dm_put(md); 1809 1810 return r; 1811 } 1812 EXPORT_SYMBOL_GPL(dm_noflush_suspending); 1813 1814 static struct block_device_operations dm_blk_dops = { 1815 .open = dm_blk_open, 1816 .release = dm_blk_close, 1817 .ioctl = dm_blk_ioctl, 1818 .getgeo = dm_blk_getgeo, 1819 .owner = THIS_MODULE 1820 }; 1821 1822 EXPORT_SYMBOL(dm_get_mapinfo); 1823 1824 /* 1825 * module hooks 1826 */ 1827 module_init(dm_init); 1828 module_exit(dm_exit); 1829 1830 module_param(major, uint, 0); 1831 MODULE_PARM_DESC(major, "The major number of the device mapper"); 1832 MODULE_DESCRIPTION(DM_NAME " driver"); 1833 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); 1834 MODULE_LICENSE("GPL"); 1835