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 if (!bio_barrier(io->bio)) 541 bio_list_add_head(&md->deferred, 542 io->bio); 543 } else 544 /* noflush suspend was interrupted. */ 545 io->error = -EIO; 546 spin_unlock_irqrestore(&md->deferred_lock, flags); 547 } 548 549 io_error = io->error; 550 bio = io->bio; 551 552 if (bio_barrier(bio)) { 553 /* 554 * There can be just one barrier request so we use 555 * a per-device variable for error reporting. 556 * Note that you can't touch the bio after end_io_acct 557 */ 558 md->barrier_error = io_error; 559 end_io_acct(io); 560 } else { 561 end_io_acct(io); 562 563 if (io_error != DM_ENDIO_REQUEUE) { 564 trace_block_bio_complete(md->queue, bio); 565 566 bio_endio(bio, io_error); 567 } 568 } 569 570 free_io(md, io); 571 } 572 } 573 574 static void clone_endio(struct bio *bio, int error) 575 { 576 int r = 0; 577 struct dm_target_io *tio = bio->bi_private; 578 struct dm_io *io = tio->io; 579 struct mapped_device *md = tio->io->md; 580 dm_endio_fn endio = tio->ti->type->end_io; 581 582 if (!bio_flagged(bio, BIO_UPTODATE) && !error) 583 error = -EIO; 584 585 if (endio) { 586 r = endio(tio->ti, bio, error, &tio->info); 587 if (r < 0 || r == DM_ENDIO_REQUEUE) 588 /* 589 * error and requeue request are handled 590 * in dec_pending(). 591 */ 592 error = r; 593 else if (r == DM_ENDIO_INCOMPLETE) 594 /* The target will handle the io */ 595 return; 596 else if (r) { 597 DMWARN("unimplemented target endio return value: %d", r); 598 BUG(); 599 } 600 } 601 602 /* 603 * Store md for cleanup instead of tio which is about to get freed. 604 */ 605 bio->bi_private = md->bs; 606 607 free_tio(md, tio); 608 bio_put(bio); 609 dec_pending(io, error); 610 } 611 612 static sector_t max_io_len(struct mapped_device *md, 613 sector_t sector, struct dm_target *ti) 614 { 615 sector_t offset = sector - ti->begin; 616 sector_t len = ti->len - offset; 617 618 /* 619 * Does the target need to split even further ? 620 */ 621 if (ti->split_io) { 622 sector_t boundary; 623 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) 624 - offset; 625 if (len > boundary) 626 len = boundary; 627 } 628 629 return len; 630 } 631 632 static void __map_bio(struct dm_target *ti, struct bio *clone, 633 struct dm_target_io *tio) 634 { 635 int r; 636 sector_t sector; 637 struct mapped_device *md; 638 639 /* 640 * Sanity checks. 641 */ 642 BUG_ON(!clone->bi_size); 643 644 clone->bi_end_io = clone_endio; 645 clone->bi_private = tio; 646 647 /* 648 * Map the clone. If r == 0 we don't need to do 649 * anything, the target has assumed ownership of 650 * this io. 651 */ 652 atomic_inc(&tio->io->io_count); 653 sector = clone->bi_sector; 654 r = ti->type->map(ti, clone, &tio->info); 655 if (r == DM_MAPIO_REMAPPED) { 656 /* the bio has been remapped so dispatch it */ 657 658 trace_block_remap(bdev_get_queue(clone->bi_bdev), clone, 659 tio->io->bio->bi_bdev->bd_dev, sector); 660 661 generic_make_request(clone); 662 } else if (r < 0 || r == DM_MAPIO_REQUEUE) { 663 /* error the io and bail out, or requeue it if needed */ 664 md = tio->io->md; 665 dec_pending(tio->io, r); 666 /* 667 * Store bio_set for cleanup. 668 */ 669 clone->bi_private = md->bs; 670 bio_put(clone); 671 free_tio(md, tio); 672 } else if (r) { 673 DMWARN("unimplemented target map return value: %d", r); 674 BUG(); 675 } 676 } 677 678 struct clone_info { 679 struct mapped_device *md; 680 struct dm_table *map; 681 struct bio *bio; 682 struct dm_io *io; 683 sector_t sector; 684 sector_t sector_count; 685 unsigned short idx; 686 }; 687 688 static void dm_bio_destructor(struct bio *bio) 689 { 690 struct bio_set *bs = bio->bi_private; 691 692 bio_free(bio, bs); 693 } 694 695 /* 696 * Creates a little bio that is just does part of a bvec. 697 */ 698 static struct bio *split_bvec(struct bio *bio, sector_t sector, 699 unsigned short idx, unsigned int offset, 700 unsigned int len, struct bio_set *bs) 701 { 702 struct bio *clone; 703 struct bio_vec *bv = bio->bi_io_vec + idx; 704 705 clone = bio_alloc_bioset(GFP_NOIO, 1, bs); 706 clone->bi_destructor = dm_bio_destructor; 707 *clone->bi_io_vec = *bv; 708 709 clone->bi_sector = sector; 710 clone->bi_bdev = bio->bi_bdev; 711 clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER); 712 clone->bi_vcnt = 1; 713 clone->bi_size = to_bytes(len); 714 clone->bi_io_vec->bv_offset = offset; 715 clone->bi_io_vec->bv_len = clone->bi_size; 716 clone->bi_flags |= 1 << BIO_CLONED; 717 718 if (bio_integrity(bio)) { 719 bio_integrity_clone(clone, bio, GFP_NOIO); 720 bio_integrity_trim(clone, 721 bio_sector_offset(bio, idx, offset), len); 722 } 723 724 return clone; 725 } 726 727 /* 728 * Creates a bio that consists of range of complete bvecs. 729 */ 730 static struct bio *clone_bio(struct bio *bio, sector_t sector, 731 unsigned short idx, unsigned short bv_count, 732 unsigned int len, struct bio_set *bs) 733 { 734 struct bio *clone; 735 736 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); 737 __bio_clone(clone, bio); 738 clone->bi_rw &= ~(1 << BIO_RW_BARRIER); 739 clone->bi_destructor = dm_bio_destructor; 740 clone->bi_sector = sector; 741 clone->bi_idx = idx; 742 clone->bi_vcnt = idx + bv_count; 743 clone->bi_size = to_bytes(len); 744 clone->bi_flags &= ~(1 << BIO_SEG_VALID); 745 746 if (bio_integrity(bio)) { 747 bio_integrity_clone(clone, bio, GFP_NOIO); 748 749 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size) 750 bio_integrity_trim(clone, 751 bio_sector_offset(bio, idx, 0), len); 752 } 753 754 return clone; 755 } 756 757 static int __clone_and_map(struct clone_info *ci) 758 { 759 struct bio *clone, *bio = ci->bio; 760 struct dm_target *ti; 761 sector_t len = 0, max; 762 struct dm_target_io *tio; 763 764 ti = dm_table_find_target(ci->map, ci->sector); 765 if (!dm_target_is_valid(ti)) 766 return -EIO; 767 768 max = max_io_len(ci->md, ci->sector, ti); 769 770 /* 771 * Allocate a target io object. 772 */ 773 tio = alloc_tio(ci->md); 774 tio->io = ci->io; 775 tio->ti = ti; 776 memset(&tio->info, 0, sizeof(tio->info)); 777 778 if (ci->sector_count <= max) { 779 /* 780 * Optimise for the simple case where we can do all of 781 * the remaining io with a single clone. 782 */ 783 clone = clone_bio(bio, ci->sector, ci->idx, 784 bio->bi_vcnt - ci->idx, ci->sector_count, 785 ci->md->bs); 786 __map_bio(ti, clone, tio); 787 ci->sector_count = 0; 788 789 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { 790 /* 791 * There are some bvecs that don't span targets. 792 * Do as many of these as possible. 793 */ 794 int i; 795 sector_t remaining = max; 796 sector_t bv_len; 797 798 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { 799 bv_len = to_sector(bio->bi_io_vec[i].bv_len); 800 801 if (bv_len > remaining) 802 break; 803 804 remaining -= bv_len; 805 len += bv_len; 806 } 807 808 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len, 809 ci->md->bs); 810 __map_bio(ti, clone, tio); 811 812 ci->sector += len; 813 ci->sector_count -= len; 814 ci->idx = i; 815 816 } else { 817 /* 818 * Handle a bvec that must be split between two or more targets. 819 */ 820 struct bio_vec *bv = bio->bi_io_vec + ci->idx; 821 sector_t remaining = to_sector(bv->bv_len); 822 unsigned int offset = 0; 823 824 do { 825 if (offset) { 826 ti = dm_table_find_target(ci->map, ci->sector); 827 if (!dm_target_is_valid(ti)) 828 return -EIO; 829 830 max = max_io_len(ci->md, ci->sector, ti); 831 832 tio = alloc_tio(ci->md); 833 tio->io = ci->io; 834 tio->ti = ti; 835 memset(&tio->info, 0, sizeof(tio->info)); 836 } 837 838 len = min(remaining, max); 839 840 clone = split_bvec(bio, ci->sector, ci->idx, 841 bv->bv_offset + offset, len, 842 ci->md->bs); 843 844 __map_bio(ti, clone, tio); 845 846 ci->sector += len; 847 ci->sector_count -= len; 848 offset += to_bytes(len); 849 } while (remaining -= len); 850 851 ci->idx++; 852 } 853 854 return 0; 855 } 856 857 /* 858 * Split the bio into several clones and submit it to targets. 859 */ 860 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) 861 { 862 struct clone_info ci; 863 int error = 0; 864 865 ci.map = dm_get_table(md); 866 if (unlikely(!ci.map)) { 867 if (!bio_barrier(bio)) 868 bio_io_error(bio); 869 else 870 md->barrier_error = -EIO; 871 return; 872 } 873 874 ci.md = md; 875 ci.bio = bio; 876 ci.io = alloc_io(md); 877 ci.io->error = 0; 878 atomic_set(&ci.io->io_count, 1); 879 ci.io->bio = bio; 880 ci.io->md = md; 881 ci.sector = bio->bi_sector; 882 ci.sector_count = bio_sectors(bio); 883 ci.idx = bio->bi_idx; 884 885 start_io_acct(ci.io); 886 while (ci.sector_count && !error) 887 error = __clone_and_map(&ci); 888 889 /* drop the extra reference count */ 890 dec_pending(ci.io, error); 891 dm_table_put(ci.map); 892 } 893 /*----------------------------------------------------------------- 894 * CRUD END 895 *---------------------------------------------------------------*/ 896 897 static int dm_merge_bvec(struct request_queue *q, 898 struct bvec_merge_data *bvm, 899 struct bio_vec *biovec) 900 { 901 struct mapped_device *md = q->queuedata; 902 struct dm_table *map = dm_get_table(md); 903 struct dm_target *ti; 904 sector_t max_sectors; 905 int max_size = 0; 906 907 if (unlikely(!map)) 908 goto out; 909 910 ti = dm_table_find_target(map, bvm->bi_sector); 911 if (!dm_target_is_valid(ti)) 912 goto out_table; 913 914 /* 915 * Find maximum amount of I/O that won't need splitting 916 */ 917 max_sectors = min(max_io_len(md, bvm->bi_sector, ti), 918 (sector_t) BIO_MAX_SECTORS); 919 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; 920 if (max_size < 0) 921 max_size = 0; 922 923 /* 924 * merge_bvec_fn() returns number of bytes 925 * it can accept at this offset 926 * max is precomputed maximal io size 927 */ 928 if (max_size && ti->type->merge) 929 max_size = ti->type->merge(ti, bvm, biovec, max_size); 930 /* 931 * If the target doesn't support merge method and some of the devices 932 * provided their merge_bvec method (we know this by looking at 933 * queue_max_hw_sectors), then we can't allow bios with multiple vector 934 * entries. So always set max_size to 0, and the code below allows 935 * just one page. 936 */ 937 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) 938 939 max_size = 0; 940 941 out_table: 942 dm_table_put(map); 943 944 out: 945 /* 946 * Always allow an entire first page 947 */ 948 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) 949 max_size = biovec->bv_len; 950 951 return max_size; 952 } 953 954 /* 955 * The request function that just remaps the bio built up by 956 * dm_merge_bvec. 957 */ 958 static int dm_request(struct request_queue *q, struct bio *bio) 959 { 960 int rw = bio_data_dir(bio); 961 struct mapped_device *md = q->queuedata; 962 int cpu; 963 964 down_read(&md->io_lock); 965 966 cpu = part_stat_lock(); 967 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]); 968 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio)); 969 part_stat_unlock(); 970 971 /* 972 * If we're suspended or the thread is processing barriers 973 * we have to queue this io for later. 974 */ 975 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) || 976 unlikely(bio_barrier(bio))) { 977 up_read(&md->io_lock); 978 979 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && 980 bio_rw(bio) == READA) { 981 bio_io_error(bio); 982 return 0; 983 } 984 985 queue_io(md, bio); 986 987 return 0; 988 } 989 990 __split_and_process_bio(md, bio); 991 up_read(&md->io_lock); 992 return 0; 993 } 994 995 static void dm_unplug_all(struct request_queue *q) 996 { 997 struct mapped_device *md = q->queuedata; 998 struct dm_table *map = dm_get_table(md); 999 1000 if (map) { 1001 dm_table_unplug_all(map); 1002 dm_table_put(map); 1003 } 1004 } 1005 1006 static int dm_any_congested(void *congested_data, int bdi_bits) 1007 { 1008 int r = bdi_bits; 1009 struct mapped_device *md = congested_data; 1010 struct dm_table *map; 1011 1012 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { 1013 map = dm_get_table(md); 1014 if (map) { 1015 r = dm_table_any_congested(map, bdi_bits); 1016 dm_table_put(map); 1017 } 1018 } 1019 1020 return r; 1021 } 1022 1023 /*----------------------------------------------------------------- 1024 * An IDR is used to keep track of allocated minor numbers. 1025 *---------------------------------------------------------------*/ 1026 static DEFINE_IDR(_minor_idr); 1027 1028 static void free_minor(int minor) 1029 { 1030 spin_lock(&_minor_lock); 1031 idr_remove(&_minor_idr, minor); 1032 spin_unlock(&_minor_lock); 1033 } 1034 1035 /* 1036 * See if the device with a specific minor # is free. 1037 */ 1038 static int specific_minor(int minor) 1039 { 1040 int r, m; 1041 1042 if (minor >= (1 << MINORBITS)) 1043 return -EINVAL; 1044 1045 r = idr_pre_get(&_minor_idr, GFP_KERNEL); 1046 if (!r) 1047 return -ENOMEM; 1048 1049 spin_lock(&_minor_lock); 1050 1051 if (idr_find(&_minor_idr, minor)) { 1052 r = -EBUSY; 1053 goto out; 1054 } 1055 1056 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); 1057 if (r) 1058 goto out; 1059 1060 if (m != minor) { 1061 idr_remove(&_minor_idr, m); 1062 r = -EBUSY; 1063 goto out; 1064 } 1065 1066 out: 1067 spin_unlock(&_minor_lock); 1068 return r; 1069 } 1070 1071 static int next_free_minor(int *minor) 1072 { 1073 int r, m; 1074 1075 r = idr_pre_get(&_minor_idr, GFP_KERNEL); 1076 if (!r) 1077 return -ENOMEM; 1078 1079 spin_lock(&_minor_lock); 1080 1081 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); 1082 if (r) 1083 goto out; 1084 1085 if (m >= (1 << MINORBITS)) { 1086 idr_remove(&_minor_idr, m); 1087 r = -ENOSPC; 1088 goto out; 1089 } 1090 1091 *minor = m; 1092 1093 out: 1094 spin_unlock(&_minor_lock); 1095 return r; 1096 } 1097 1098 static struct block_device_operations dm_blk_dops; 1099 1100 static void dm_wq_work(struct work_struct *work); 1101 1102 /* 1103 * Allocate and initialise a blank device with a given minor. 1104 */ 1105 static struct mapped_device *alloc_dev(int minor) 1106 { 1107 int r; 1108 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL); 1109 void *old_md; 1110 1111 if (!md) { 1112 DMWARN("unable to allocate device, out of memory."); 1113 return NULL; 1114 } 1115 1116 if (!try_module_get(THIS_MODULE)) 1117 goto bad_module_get; 1118 1119 /* get a minor number for the dev */ 1120 if (minor == DM_ANY_MINOR) 1121 r = next_free_minor(&minor); 1122 else 1123 r = specific_minor(minor); 1124 if (r < 0) 1125 goto bad_minor; 1126 1127 init_rwsem(&md->io_lock); 1128 mutex_init(&md->suspend_lock); 1129 spin_lock_init(&md->deferred_lock); 1130 rwlock_init(&md->map_lock); 1131 atomic_set(&md->holders, 1); 1132 atomic_set(&md->open_count, 0); 1133 atomic_set(&md->event_nr, 0); 1134 atomic_set(&md->uevent_seq, 0); 1135 INIT_LIST_HEAD(&md->uevent_list); 1136 spin_lock_init(&md->uevent_lock); 1137 1138 md->queue = blk_alloc_queue(GFP_KERNEL); 1139 if (!md->queue) 1140 goto bad_queue; 1141 1142 md->queue->queuedata = md; 1143 md->queue->backing_dev_info.congested_fn = dm_any_congested; 1144 md->queue->backing_dev_info.congested_data = md; 1145 blk_queue_make_request(md->queue, dm_request); 1146 blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL); 1147 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); 1148 md->queue->unplug_fn = dm_unplug_all; 1149 blk_queue_merge_bvec(md->queue, dm_merge_bvec); 1150 1151 md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); 1152 if (!md->io_pool) 1153 goto bad_io_pool; 1154 1155 md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); 1156 if (!md->tio_pool) 1157 goto bad_tio_pool; 1158 1159 md->bs = bioset_create(16, 0); 1160 if (!md->bs) 1161 goto bad_no_bioset; 1162 1163 md->disk = alloc_disk(1); 1164 if (!md->disk) 1165 goto bad_disk; 1166 1167 atomic_set(&md->pending, 0); 1168 init_waitqueue_head(&md->wait); 1169 INIT_WORK(&md->work, dm_wq_work); 1170 init_waitqueue_head(&md->eventq); 1171 1172 md->disk->major = _major; 1173 md->disk->first_minor = minor; 1174 md->disk->fops = &dm_blk_dops; 1175 md->disk->queue = md->queue; 1176 md->disk->private_data = md; 1177 sprintf(md->disk->disk_name, "dm-%d", minor); 1178 add_disk(md->disk); 1179 format_dev_t(md->name, MKDEV(_major, minor)); 1180 1181 md->wq = create_singlethread_workqueue("kdmflush"); 1182 if (!md->wq) 1183 goto bad_thread; 1184 1185 md->bdev = bdget_disk(md->disk, 0); 1186 if (!md->bdev) 1187 goto bad_bdev; 1188 1189 /* Populate the mapping, nobody knows we exist yet */ 1190 spin_lock(&_minor_lock); 1191 old_md = idr_replace(&_minor_idr, md, minor); 1192 spin_unlock(&_minor_lock); 1193 1194 BUG_ON(old_md != MINOR_ALLOCED); 1195 1196 return md; 1197 1198 bad_bdev: 1199 destroy_workqueue(md->wq); 1200 bad_thread: 1201 put_disk(md->disk); 1202 bad_disk: 1203 bioset_free(md->bs); 1204 bad_no_bioset: 1205 mempool_destroy(md->tio_pool); 1206 bad_tio_pool: 1207 mempool_destroy(md->io_pool); 1208 bad_io_pool: 1209 blk_cleanup_queue(md->queue); 1210 bad_queue: 1211 free_minor(minor); 1212 bad_minor: 1213 module_put(THIS_MODULE); 1214 bad_module_get: 1215 kfree(md); 1216 return NULL; 1217 } 1218 1219 static void unlock_fs(struct mapped_device *md); 1220 1221 static void free_dev(struct mapped_device *md) 1222 { 1223 int minor = MINOR(disk_devt(md->disk)); 1224 1225 unlock_fs(md); 1226 bdput(md->bdev); 1227 destroy_workqueue(md->wq); 1228 mempool_destroy(md->tio_pool); 1229 mempool_destroy(md->io_pool); 1230 bioset_free(md->bs); 1231 blk_integrity_unregister(md->disk); 1232 del_gendisk(md->disk); 1233 free_minor(minor); 1234 1235 spin_lock(&_minor_lock); 1236 md->disk->private_data = NULL; 1237 spin_unlock(&_minor_lock); 1238 1239 put_disk(md->disk); 1240 blk_cleanup_queue(md->queue); 1241 module_put(THIS_MODULE); 1242 kfree(md); 1243 } 1244 1245 /* 1246 * Bind a table to the device. 1247 */ 1248 static void event_callback(void *context) 1249 { 1250 unsigned long flags; 1251 LIST_HEAD(uevents); 1252 struct mapped_device *md = (struct mapped_device *) context; 1253 1254 spin_lock_irqsave(&md->uevent_lock, flags); 1255 list_splice_init(&md->uevent_list, &uevents); 1256 spin_unlock_irqrestore(&md->uevent_lock, flags); 1257 1258 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); 1259 1260 atomic_inc(&md->event_nr); 1261 wake_up(&md->eventq); 1262 } 1263 1264 static void __set_size(struct mapped_device *md, sector_t size) 1265 { 1266 set_capacity(md->disk, size); 1267 1268 mutex_lock(&md->bdev->bd_inode->i_mutex); 1269 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); 1270 mutex_unlock(&md->bdev->bd_inode->i_mutex); 1271 } 1272 1273 static int __bind(struct mapped_device *md, struct dm_table *t) 1274 { 1275 struct request_queue *q = md->queue; 1276 sector_t size; 1277 1278 size = dm_table_get_size(t); 1279 1280 /* 1281 * Wipe any geometry if the size of the table changed. 1282 */ 1283 if (size != get_capacity(md->disk)) 1284 memset(&md->geometry, 0, sizeof(md->geometry)); 1285 1286 __set_size(md, size); 1287 1288 if (!size) { 1289 dm_table_destroy(t); 1290 return 0; 1291 } 1292 1293 dm_table_event_callback(t, event_callback, md); 1294 1295 write_lock(&md->map_lock); 1296 md->map = t; 1297 dm_table_set_restrictions(t, q); 1298 write_unlock(&md->map_lock); 1299 1300 return 0; 1301 } 1302 1303 static void __unbind(struct mapped_device *md) 1304 { 1305 struct dm_table *map = md->map; 1306 1307 if (!map) 1308 return; 1309 1310 dm_table_event_callback(map, NULL, NULL); 1311 write_lock(&md->map_lock); 1312 md->map = NULL; 1313 write_unlock(&md->map_lock); 1314 dm_table_destroy(map); 1315 } 1316 1317 /* 1318 * Constructor for a new device. 1319 */ 1320 int dm_create(int minor, struct mapped_device **result) 1321 { 1322 struct mapped_device *md; 1323 1324 md = alloc_dev(minor); 1325 if (!md) 1326 return -ENXIO; 1327 1328 dm_sysfs_init(md); 1329 1330 *result = md; 1331 return 0; 1332 } 1333 1334 static struct mapped_device *dm_find_md(dev_t dev) 1335 { 1336 struct mapped_device *md; 1337 unsigned minor = MINOR(dev); 1338 1339 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) 1340 return NULL; 1341 1342 spin_lock(&_minor_lock); 1343 1344 md = idr_find(&_minor_idr, minor); 1345 if (md && (md == MINOR_ALLOCED || 1346 (MINOR(disk_devt(dm_disk(md))) != minor) || 1347 test_bit(DMF_FREEING, &md->flags))) { 1348 md = NULL; 1349 goto out; 1350 } 1351 1352 out: 1353 spin_unlock(&_minor_lock); 1354 1355 return md; 1356 } 1357 1358 struct mapped_device *dm_get_md(dev_t dev) 1359 { 1360 struct mapped_device *md = dm_find_md(dev); 1361 1362 if (md) 1363 dm_get(md); 1364 1365 return md; 1366 } 1367 1368 void *dm_get_mdptr(struct mapped_device *md) 1369 { 1370 return md->interface_ptr; 1371 } 1372 1373 void dm_set_mdptr(struct mapped_device *md, void *ptr) 1374 { 1375 md->interface_ptr = ptr; 1376 } 1377 1378 void dm_get(struct mapped_device *md) 1379 { 1380 atomic_inc(&md->holders); 1381 } 1382 1383 const char *dm_device_name(struct mapped_device *md) 1384 { 1385 return md->name; 1386 } 1387 EXPORT_SYMBOL_GPL(dm_device_name); 1388 1389 void dm_put(struct mapped_device *md) 1390 { 1391 struct dm_table *map; 1392 1393 BUG_ON(test_bit(DMF_FREEING, &md->flags)); 1394 1395 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) { 1396 map = dm_get_table(md); 1397 idr_replace(&_minor_idr, MINOR_ALLOCED, 1398 MINOR(disk_devt(dm_disk(md)))); 1399 set_bit(DMF_FREEING, &md->flags); 1400 spin_unlock(&_minor_lock); 1401 if (!dm_suspended(md)) { 1402 dm_table_presuspend_targets(map); 1403 dm_table_postsuspend_targets(map); 1404 } 1405 dm_sysfs_exit(md); 1406 dm_table_put(map); 1407 __unbind(md); 1408 free_dev(md); 1409 } 1410 } 1411 EXPORT_SYMBOL_GPL(dm_put); 1412 1413 static int dm_wait_for_completion(struct mapped_device *md, int interruptible) 1414 { 1415 int r = 0; 1416 DECLARE_WAITQUEUE(wait, current); 1417 1418 dm_unplug_all(md->queue); 1419 1420 add_wait_queue(&md->wait, &wait); 1421 1422 while (1) { 1423 set_current_state(interruptible); 1424 1425 smp_mb(); 1426 if (!atomic_read(&md->pending)) 1427 break; 1428 1429 if (interruptible == TASK_INTERRUPTIBLE && 1430 signal_pending(current)) { 1431 r = -EINTR; 1432 break; 1433 } 1434 1435 io_schedule(); 1436 } 1437 set_current_state(TASK_RUNNING); 1438 1439 remove_wait_queue(&md->wait, &wait); 1440 1441 return r; 1442 } 1443 1444 static void dm_flush(struct mapped_device *md) 1445 { 1446 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); 1447 } 1448 1449 static void process_barrier(struct mapped_device *md, struct bio *bio) 1450 { 1451 dm_flush(md); 1452 1453 if (bio_empty_barrier(bio)) { 1454 bio_endio(bio, 0); 1455 return; 1456 } 1457 1458 __split_and_process_bio(md, bio); 1459 dm_flush(md); 1460 1461 if (md->barrier_error != DM_ENDIO_REQUEUE) 1462 bio_endio(bio, md->barrier_error); 1463 else { 1464 spin_lock_irq(&md->deferred_lock); 1465 bio_list_add_head(&md->deferred, bio); 1466 spin_unlock_irq(&md->deferred_lock); 1467 } 1468 } 1469 1470 /* 1471 * Process the deferred bios 1472 */ 1473 static void dm_wq_work(struct work_struct *work) 1474 { 1475 struct mapped_device *md = container_of(work, struct mapped_device, 1476 work); 1477 struct bio *c; 1478 1479 down_write(&md->io_lock); 1480 1481 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { 1482 spin_lock_irq(&md->deferred_lock); 1483 c = bio_list_pop(&md->deferred); 1484 spin_unlock_irq(&md->deferred_lock); 1485 1486 if (!c) { 1487 clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags); 1488 break; 1489 } 1490 1491 up_write(&md->io_lock); 1492 1493 if (bio_barrier(c)) 1494 process_barrier(md, c); 1495 else 1496 __split_and_process_bio(md, c); 1497 1498 down_write(&md->io_lock); 1499 } 1500 1501 up_write(&md->io_lock); 1502 } 1503 1504 static void dm_queue_flush(struct mapped_device *md) 1505 { 1506 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); 1507 smp_mb__after_clear_bit(); 1508 queue_work(md->wq, &md->work); 1509 } 1510 1511 /* 1512 * Swap in a new table (destroying old one). 1513 */ 1514 int dm_swap_table(struct mapped_device *md, struct dm_table *table) 1515 { 1516 int r = -EINVAL; 1517 1518 mutex_lock(&md->suspend_lock); 1519 1520 /* device must be suspended */ 1521 if (!dm_suspended(md)) 1522 goto out; 1523 1524 __unbind(md); 1525 r = __bind(md, table); 1526 1527 out: 1528 mutex_unlock(&md->suspend_lock); 1529 return r; 1530 } 1531 1532 /* 1533 * Functions to lock and unlock any filesystem running on the 1534 * device. 1535 */ 1536 static int lock_fs(struct mapped_device *md) 1537 { 1538 int r; 1539 1540 WARN_ON(md->frozen_sb); 1541 1542 md->frozen_sb = freeze_bdev(md->bdev); 1543 if (IS_ERR(md->frozen_sb)) { 1544 r = PTR_ERR(md->frozen_sb); 1545 md->frozen_sb = NULL; 1546 return r; 1547 } 1548 1549 set_bit(DMF_FROZEN, &md->flags); 1550 1551 return 0; 1552 } 1553 1554 static void unlock_fs(struct mapped_device *md) 1555 { 1556 if (!test_bit(DMF_FROZEN, &md->flags)) 1557 return; 1558 1559 thaw_bdev(md->bdev, md->frozen_sb); 1560 md->frozen_sb = NULL; 1561 clear_bit(DMF_FROZEN, &md->flags); 1562 } 1563 1564 /* 1565 * We need to be able to change a mapping table under a mounted 1566 * filesystem. For example we might want to move some data in 1567 * the background. Before the table can be swapped with 1568 * dm_bind_table, dm_suspend must be called to flush any in 1569 * flight bios and ensure that any further io gets deferred. 1570 */ 1571 int dm_suspend(struct mapped_device *md, unsigned suspend_flags) 1572 { 1573 struct dm_table *map = NULL; 1574 int r = 0; 1575 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; 1576 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; 1577 1578 mutex_lock(&md->suspend_lock); 1579 1580 if (dm_suspended(md)) { 1581 r = -EINVAL; 1582 goto out_unlock; 1583 } 1584 1585 map = dm_get_table(md); 1586 1587 /* 1588 * DMF_NOFLUSH_SUSPENDING must be set before presuspend. 1589 * This flag is cleared before dm_suspend returns. 1590 */ 1591 if (noflush) 1592 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 1593 1594 /* This does not get reverted if there's an error later. */ 1595 dm_table_presuspend_targets(map); 1596 1597 /* 1598 * Flush I/O to the device. noflush supersedes do_lockfs, 1599 * because lock_fs() needs to flush I/Os. 1600 */ 1601 if (!noflush && do_lockfs) { 1602 r = lock_fs(md); 1603 if (r) 1604 goto out; 1605 } 1606 1607 /* 1608 * Here we must make sure that no processes are submitting requests 1609 * to target drivers i.e. no one may be executing 1610 * __split_and_process_bio. This is called from dm_request and 1611 * dm_wq_work. 1612 * 1613 * To get all processes out of __split_and_process_bio in dm_request, 1614 * we take the write lock. To prevent any process from reentering 1615 * __split_and_process_bio from dm_request, we set 1616 * DMF_QUEUE_IO_TO_THREAD. 1617 * 1618 * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND 1619 * and call flush_workqueue(md->wq). flush_workqueue will wait until 1620 * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any 1621 * further calls to __split_and_process_bio from dm_wq_work. 1622 */ 1623 down_write(&md->io_lock); 1624 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); 1625 set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags); 1626 up_write(&md->io_lock); 1627 1628 flush_workqueue(md->wq); 1629 1630 /* 1631 * At this point no more requests are entering target request routines. 1632 * We call dm_wait_for_completion to wait for all existing requests 1633 * to finish. 1634 */ 1635 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE); 1636 1637 down_write(&md->io_lock); 1638 if (noflush) 1639 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 1640 up_write(&md->io_lock); 1641 1642 /* were we interrupted ? */ 1643 if (r < 0) { 1644 dm_queue_flush(md); 1645 1646 unlock_fs(md); 1647 goto out; /* pushback list is already flushed, so skip flush */ 1648 } 1649 1650 /* 1651 * If dm_wait_for_completion returned 0, the device is completely 1652 * quiescent now. There is no request-processing activity. All new 1653 * requests are being added to md->deferred list. 1654 */ 1655 1656 dm_table_postsuspend_targets(map); 1657 1658 set_bit(DMF_SUSPENDED, &md->flags); 1659 1660 out: 1661 dm_table_put(map); 1662 1663 out_unlock: 1664 mutex_unlock(&md->suspend_lock); 1665 return r; 1666 } 1667 1668 int dm_resume(struct mapped_device *md) 1669 { 1670 int r = -EINVAL; 1671 struct dm_table *map = NULL; 1672 1673 mutex_lock(&md->suspend_lock); 1674 if (!dm_suspended(md)) 1675 goto out; 1676 1677 map = dm_get_table(md); 1678 if (!map || !dm_table_get_size(map)) 1679 goto out; 1680 1681 r = dm_table_resume_targets(map); 1682 if (r) 1683 goto out; 1684 1685 dm_queue_flush(md); 1686 1687 unlock_fs(md); 1688 1689 clear_bit(DMF_SUSPENDED, &md->flags); 1690 1691 dm_table_unplug_all(map); 1692 1693 dm_kobject_uevent(md); 1694 1695 r = 0; 1696 1697 out: 1698 dm_table_put(map); 1699 mutex_unlock(&md->suspend_lock); 1700 1701 return r; 1702 } 1703 1704 /*----------------------------------------------------------------- 1705 * Event notification. 1706 *---------------------------------------------------------------*/ 1707 void dm_kobject_uevent(struct mapped_device *md) 1708 { 1709 kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE); 1710 } 1711 1712 uint32_t dm_next_uevent_seq(struct mapped_device *md) 1713 { 1714 return atomic_add_return(1, &md->uevent_seq); 1715 } 1716 1717 uint32_t dm_get_event_nr(struct mapped_device *md) 1718 { 1719 return atomic_read(&md->event_nr); 1720 } 1721 1722 int dm_wait_event(struct mapped_device *md, int event_nr) 1723 { 1724 return wait_event_interruptible(md->eventq, 1725 (event_nr != atomic_read(&md->event_nr))); 1726 } 1727 1728 void dm_uevent_add(struct mapped_device *md, struct list_head *elist) 1729 { 1730 unsigned long flags; 1731 1732 spin_lock_irqsave(&md->uevent_lock, flags); 1733 list_add(elist, &md->uevent_list); 1734 spin_unlock_irqrestore(&md->uevent_lock, flags); 1735 } 1736 1737 /* 1738 * The gendisk is only valid as long as you have a reference 1739 * count on 'md'. 1740 */ 1741 struct gendisk *dm_disk(struct mapped_device *md) 1742 { 1743 return md->disk; 1744 } 1745 1746 struct kobject *dm_kobject(struct mapped_device *md) 1747 { 1748 return &md->kobj; 1749 } 1750 1751 /* 1752 * struct mapped_device should not be exported outside of dm.c 1753 * so use this check to verify that kobj is part of md structure 1754 */ 1755 struct mapped_device *dm_get_from_kobject(struct kobject *kobj) 1756 { 1757 struct mapped_device *md; 1758 1759 md = container_of(kobj, struct mapped_device, kobj); 1760 if (&md->kobj != kobj) 1761 return NULL; 1762 1763 if (test_bit(DMF_FREEING, &md->flags) || 1764 test_bit(DMF_DELETING, &md->flags)) 1765 return NULL; 1766 1767 dm_get(md); 1768 return md; 1769 } 1770 1771 int dm_suspended(struct mapped_device *md) 1772 { 1773 return test_bit(DMF_SUSPENDED, &md->flags); 1774 } 1775 1776 int dm_noflush_suspending(struct dm_target *ti) 1777 { 1778 struct mapped_device *md = dm_table_get_md(ti->table); 1779 int r = __noflush_suspending(md); 1780 1781 dm_put(md); 1782 1783 return r; 1784 } 1785 EXPORT_SYMBOL_GPL(dm_noflush_suspending); 1786 1787 static struct block_device_operations dm_blk_dops = { 1788 .open = dm_blk_open, 1789 .release = dm_blk_close, 1790 .ioctl = dm_blk_ioctl, 1791 .getgeo = dm_blk_getgeo, 1792 .owner = THIS_MODULE 1793 }; 1794 1795 EXPORT_SYMBOL(dm_get_mapinfo); 1796 1797 /* 1798 * module hooks 1799 */ 1800 module_init(dm_init); 1801 module_exit(dm_exit); 1802 1803 module_param(major, uint, 0); 1804 MODULE_PARM_DESC(major, "The major number of the device mapper"); 1805 MODULE_DESCRIPTION(DM_NAME " driver"); 1806 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); 1807 MODULE_LICENSE("GPL"); 1808