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/mempool.h> 18 #include <linux/slab.h> 19 #include <linux/idr.h> 20 #include <linux/hdreg.h> 21 #include <linux/delay.h> 22 23 #include <trace/events/block.h> 24 25 #define DM_MSG_PREFIX "core" 26 27 #ifdef CONFIG_PRINTK 28 /* 29 * ratelimit state to be used in DMXXX_LIMIT(). 30 */ 31 DEFINE_RATELIMIT_STATE(dm_ratelimit_state, 32 DEFAULT_RATELIMIT_INTERVAL, 33 DEFAULT_RATELIMIT_BURST); 34 EXPORT_SYMBOL(dm_ratelimit_state); 35 #endif 36 37 /* 38 * Cookies are numeric values sent with CHANGE and REMOVE 39 * uevents while resuming, removing or renaming the device. 40 */ 41 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE" 42 #define DM_COOKIE_LENGTH 24 43 44 static const char *_name = DM_NAME; 45 46 static unsigned int major = 0; 47 static unsigned int _major = 0; 48 49 static DEFINE_IDR(_minor_idr); 50 51 static DEFINE_SPINLOCK(_minor_lock); 52 /* 53 * For bio-based dm. 54 * One of these is allocated per bio. 55 */ 56 struct dm_io { 57 struct mapped_device *md; 58 int error; 59 atomic_t io_count; 60 struct bio *bio; 61 unsigned long start_time; 62 spinlock_t endio_lock; 63 }; 64 65 /* 66 * For bio-based dm. 67 * One of these is allocated per target within a bio. Hopefully 68 * this will be simplified out one day. 69 */ 70 struct dm_target_io { 71 struct dm_io *io; 72 struct dm_target *ti; 73 union map_info info; 74 struct bio clone; 75 }; 76 77 /* 78 * For request-based dm. 79 * One of these is allocated per request. 80 */ 81 struct dm_rq_target_io { 82 struct mapped_device *md; 83 struct dm_target *ti; 84 struct request *orig, clone; 85 int error; 86 union map_info info; 87 }; 88 89 /* 90 * For request-based dm - the bio clones we allocate are embedded in these 91 * structs. 92 * 93 * We allocate these with bio_alloc_bioset, using the front_pad parameter when 94 * the bioset is created - this means the bio has to come at the end of the 95 * struct. 96 */ 97 struct dm_rq_clone_bio_info { 98 struct bio *orig; 99 struct dm_rq_target_io *tio; 100 struct bio clone; 101 }; 102 103 union map_info *dm_get_mapinfo(struct bio *bio) 104 { 105 if (bio && bio->bi_private) 106 return &((struct dm_target_io *)bio->bi_private)->info; 107 return NULL; 108 } 109 110 union map_info *dm_get_rq_mapinfo(struct request *rq) 111 { 112 if (rq && rq->end_io_data) 113 return &((struct dm_rq_target_io *)rq->end_io_data)->info; 114 return NULL; 115 } 116 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo); 117 118 #define MINOR_ALLOCED ((void *)-1) 119 120 /* 121 * Bits for the md->flags field. 122 */ 123 #define DMF_BLOCK_IO_FOR_SUSPEND 0 124 #define DMF_SUSPENDED 1 125 #define DMF_FROZEN 2 126 #define DMF_FREEING 3 127 #define DMF_DELETING 4 128 #define DMF_NOFLUSH_SUSPENDING 5 129 #define DMF_MERGE_IS_OPTIONAL 6 130 131 /* 132 * Work processed by per-device workqueue. 133 */ 134 struct mapped_device { 135 struct rw_semaphore io_lock; 136 struct mutex suspend_lock; 137 rwlock_t map_lock; 138 atomic_t holders; 139 atomic_t open_count; 140 141 unsigned long flags; 142 143 struct request_queue *queue; 144 unsigned type; 145 /* Protect queue and type against concurrent access. */ 146 struct mutex type_lock; 147 148 struct target_type *immutable_target_type; 149 150 struct gendisk *disk; 151 char name[16]; 152 153 void *interface_ptr; 154 155 /* 156 * A list of ios that arrived while we were suspended. 157 */ 158 atomic_t pending[2]; 159 wait_queue_head_t wait; 160 struct work_struct work; 161 struct bio_list deferred; 162 spinlock_t deferred_lock; 163 164 /* 165 * Processing queue (flush) 166 */ 167 struct workqueue_struct *wq; 168 169 /* 170 * The current mapping. 171 */ 172 struct dm_table *map; 173 174 /* 175 * io objects are allocated from here. 176 */ 177 mempool_t *io_pool; 178 mempool_t *tio_pool; 179 180 struct bio_set *bs; 181 182 /* 183 * Event handling. 184 */ 185 atomic_t event_nr; 186 wait_queue_head_t eventq; 187 atomic_t uevent_seq; 188 struct list_head uevent_list; 189 spinlock_t uevent_lock; /* Protect access to uevent_list */ 190 191 /* 192 * freeze/thaw support require holding onto a super block 193 */ 194 struct super_block *frozen_sb; 195 struct block_device *bdev; 196 197 /* forced geometry settings */ 198 struct hd_geometry geometry; 199 200 /* sysfs handle */ 201 struct kobject kobj; 202 203 /* zero-length flush that will be cloned and submitted to targets */ 204 struct bio flush_bio; 205 }; 206 207 /* 208 * For mempools pre-allocation at the table loading time. 209 */ 210 struct dm_md_mempools { 211 mempool_t *io_pool; 212 mempool_t *tio_pool; 213 struct bio_set *bs; 214 }; 215 216 #define MIN_IOS 256 217 static struct kmem_cache *_io_cache; 218 static struct kmem_cache *_rq_tio_cache; 219 220 /* 221 * Unused now, and needs to be deleted. But since io_pool is overloaded and it's 222 * still used for _io_cache, I'm leaving this for a later cleanup 223 */ 224 static struct kmem_cache *_rq_bio_info_cache; 225 226 static int __init local_init(void) 227 { 228 int r = -ENOMEM; 229 230 /* allocate a slab for the dm_ios */ 231 _io_cache = KMEM_CACHE(dm_io, 0); 232 if (!_io_cache) 233 return r; 234 235 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0); 236 if (!_rq_tio_cache) 237 goto out_free_io_cache; 238 239 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0); 240 if (!_rq_bio_info_cache) 241 goto out_free_rq_tio_cache; 242 243 r = dm_uevent_init(); 244 if (r) 245 goto out_free_rq_bio_info_cache; 246 247 _major = major; 248 r = register_blkdev(_major, _name); 249 if (r < 0) 250 goto out_uevent_exit; 251 252 if (!_major) 253 _major = r; 254 255 return 0; 256 257 out_uevent_exit: 258 dm_uevent_exit(); 259 out_free_rq_bio_info_cache: 260 kmem_cache_destroy(_rq_bio_info_cache); 261 out_free_rq_tio_cache: 262 kmem_cache_destroy(_rq_tio_cache); 263 out_free_io_cache: 264 kmem_cache_destroy(_io_cache); 265 266 return r; 267 } 268 269 static void local_exit(void) 270 { 271 kmem_cache_destroy(_rq_bio_info_cache); 272 kmem_cache_destroy(_rq_tio_cache); 273 kmem_cache_destroy(_io_cache); 274 unregister_blkdev(_major, _name); 275 dm_uevent_exit(); 276 277 _major = 0; 278 279 DMINFO("cleaned up"); 280 } 281 282 static int (*_inits[])(void) __initdata = { 283 local_init, 284 dm_target_init, 285 dm_linear_init, 286 dm_stripe_init, 287 dm_io_init, 288 dm_kcopyd_init, 289 dm_interface_init, 290 }; 291 292 static void (*_exits[])(void) = { 293 local_exit, 294 dm_target_exit, 295 dm_linear_exit, 296 dm_stripe_exit, 297 dm_io_exit, 298 dm_kcopyd_exit, 299 dm_interface_exit, 300 }; 301 302 static int __init dm_init(void) 303 { 304 const int count = ARRAY_SIZE(_inits); 305 306 int r, i; 307 308 for (i = 0; i < count; i++) { 309 r = _inits[i](); 310 if (r) 311 goto bad; 312 } 313 314 return 0; 315 316 bad: 317 while (i--) 318 _exits[i](); 319 320 return r; 321 } 322 323 static void __exit dm_exit(void) 324 { 325 int i = ARRAY_SIZE(_exits); 326 327 while (i--) 328 _exits[i](); 329 330 /* 331 * Should be empty by this point. 332 */ 333 idr_remove_all(&_minor_idr); 334 idr_destroy(&_minor_idr); 335 } 336 337 /* 338 * Block device functions 339 */ 340 int dm_deleting_md(struct mapped_device *md) 341 { 342 return test_bit(DMF_DELETING, &md->flags); 343 } 344 345 static int dm_blk_open(struct block_device *bdev, fmode_t mode) 346 { 347 struct mapped_device *md; 348 349 spin_lock(&_minor_lock); 350 351 md = bdev->bd_disk->private_data; 352 if (!md) 353 goto out; 354 355 if (test_bit(DMF_FREEING, &md->flags) || 356 dm_deleting_md(md)) { 357 md = NULL; 358 goto out; 359 } 360 361 dm_get(md); 362 atomic_inc(&md->open_count); 363 364 out: 365 spin_unlock(&_minor_lock); 366 367 return md ? 0 : -ENXIO; 368 } 369 370 static int dm_blk_close(struct gendisk *disk, fmode_t mode) 371 { 372 struct mapped_device *md = disk->private_data; 373 374 spin_lock(&_minor_lock); 375 376 atomic_dec(&md->open_count); 377 dm_put(md); 378 379 spin_unlock(&_minor_lock); 380 381 return 0; 382 } 383 384 int dm_open_count(struct mapped_device *md) 385 { 386 return atomic_read(&md->open_count); 387 } 388 389 /* 390 * Guarantees nothing is using the device before it's deleted. 391 */ 392 int dm_lock_for_deletion(struct mapped_device *md) 393 { 394 int r = 0; 395 396 spin_lock(&_minor_lock); 397 398 if (dm_open_count(md)) 399 r = -EBUSY; 400 else 401 set_bit(DMF_DELETING, &md->flags); 402 403 spin_unlock(&_minor_lock); 404 405 return r; 406 } 407 408 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) 409 { 410 struct mapped_device *md = bdev->bd_disk->private_data; 411 412 return dm_get_geometry(md, geo); 413 } 414 415 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode, 416 unsigned int cmd, unsigned long arg) 417 { 418 struct mapped_device *md = bdev->bd_disk->private_data; 419 struct dm_table *map = dm_get_live_table(md); 420 struct dm_target *tgt; 421 int r = -ENOTTY; 422 423 if (!map || !dm_table_get_size(map)) 424 goto out; 425 426 /* We only support devices that have a single target */ 427 if (dm_table_get_num_targets(map) != 1) 428 goto out; 429 430 tgt = dm_table_get_target(map, 0); 431 432 if (dm_suspended_md(md)) { 433 r = -EAGAIN; 434 goto out; 435 } 436 437 if (tgt->type->ioctl) 438 r = tgt->type->ioctl(tgt, cmd, arg); 439 440 out: 441 dm_table_put(map); 442 443 return r; 444 } 445 446 static struct dm_io *alloc_io(struct mapped_device *md) 447 { 448 return mempool_alloc(md->io_pool, GFP_NOIO); 449 } 450 451 static void free_io(struct mapped_device *md, struct dm_io *io) 452 { 453 mempool_free(io, md->io_pool); 454 } 455 456 static void free_tio(struct mapped_device *md, struct dm_target_io *tio) 457 { 458 bio_put(&tio->clone); 459 } 460 461 static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md, 462 gfp_t gfp_mask) 463 { 464 return mempool_alloc(md->tio_pool, gfp_mask); 465 } 466 467 static void free_rq_tio(struct dm_rq_target_io *tio) 468 { 469 mempool_free(tio, tio->md->tio_pool); 470 } 471 472 static int md_in_flight(struct mapped_device *md) 473 { 474 return atomic_read(&md->pending[READ]) + 475 atomic_read(&md->pending[WRITE]); 476 } 477 478 static void start_io_acct(struct dm_io *io) 479 { 480 struct mapped_device *md = io->md; 481 int cpu; 482 int rw = bio_data_dir(io->bio); 483 484 io->start_time = jiffies; 485 486 cpu = part_stat_lock(); 487 part_round_stats(cpu, &dm_disk(md)->part0); 488 part_stat_unlock(); 489 atomic_set(&dm_disk(md)->part0.in_flight[rw], 490 atomic_inc_return(&md->pending[rw])); 491 } 492 493 static void end_io_acct(struct dm_io *io) 494 { 495 struct mapped_device *md = io->md; 496 struct bio *bio = io->bio; 497 unsigned long duration = jiffies - io->start_time; 498 int pending, cpu; 499 int rw = bio_data_dir(bio); 500 501 cpu = part_stat_lock(); 502 part_round_stats(cpu, &dm_disk(md)->part0); 503 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration); 504 part_stat_unlock(); 505 506 /* 507 * After this is decremented the bio must not be touched if it is 508 * a flush. 509 */ 510 pending = atomic_dec_return(&md->pending[rw]); 511 atomic_set(&dm_disk(md)->part0.in_flight[rw], pending); 512 pending += atomic_read(&md->pending[rw^0x1]); 513 514 /* nudge anyone waiting on suspend queue */ 515 if (!pending) 516 wake_up(&md->wait); 517 } 518 519 /* 520 * Add the bio to the list of deferred io. 521 */ 522 static void queue_io(struct mapped_device *md, struct bio *bio) 523 { 524 unsigned long flags; 525 526 spin_lock_irqsave(&md->deferred_lock, flags); 527 bio_list_add(&md->deferred, bio); 528 spin_unlock_irqrestore(&md->deferred_lock, flags); 529 queue_work(md->wq, &md->work); 530 } 531 532 /* 533 * Everyone (including functions in this file), should use this 534 * function to access the md->map field, and make sure they call 535 * dm_table_put() when finished. 536 */ 537 struct dm_table *dm_get_live_table(struct mapped_device *md) 538 { 539 struct dm_table *t; 540 unsigned long flags; 541 542 read_lock_irqsave(&md->map_lock, flags); 543 t = md->map; 544 if (t) 545 dm_table_get(t); 546 read_unlock_irqrestore(&md->map_lock, flags); 547 548 return t; 549 } 550 551 /* 552 * Get the geometry associated with a dm device 553 */ 554 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo) 555 { 556 *geo = md->geometry; 557 558 return 0; 559 } 560 561 /* 562 * Set the geometry of a device. 563 */ 564 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo) 565 { 566 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors; 567 568 if (geo->start > sz) { 569 DMWARN("Start sector is beyond the geometry limits."); 570 return -EINVAL; 571 } 572 573 md->geometry = *geo; 574 575 return 0; 576 } 577 578 /*----------------------------------------------------------------- 579 * CRUD START: 580 * A more elegant soln is in the works that uses the queue 581 * merge fn, unfortunately there are a couple of changes to 582 * the block layer that I want to make for this. So in the 583 * interests of getting something for people to use I give 584 * you this clearly demarcated crap. 585 *---------------------------------------------------------------*/ 586 587 static int __noflush_suspending(struct mapped_device *md) 588 { 589 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 590 } 591 592 /* 593 * Decrements the number of outstanding ios that a bio has been 594 * cloned into, completing the original io if necc. 595 */ 596 static void dec_pending(struct dm_io *io, int error) 597 { 598 unsigned long flags; 599 int io_error; 600 struct bio *bio; 601 struct mapped_device *md = io->md; 602 603 /* Push-back supersedes any I/O errors */ 604 if (unlikely(error)) { 605 spin_lock_irqsave(&io->endio_lock, flags); 606 if (!(io->error > 0 && __noflush_suspending(md))) 607 io->error = error; 608 spin_unlock_irqrestore(&io->endio_lock, flags); 609 } 610 611 if (atomic_dec_and_test(&io->io_count)) { 612 if (io->error == DM_ENDIO_REQUEUE) { 613 /* 614 * Target requested pushing back the I/O. 615 */ 616 spin_lock_irqsave(&md->deferred_lock, flags); 617 if (__noflush_suspending(md)) 618 bio_list_add_head(&md->deferred, io->bio); 619 else 620 /* noflush suspend was interrupted. */ 621 io->error = -EIO; 622 spin_unlock_irqrestore(&md->deferred_lock, flags); 623 } 624 625 io_error = io->error; 626 bio = io->bio; 627 end_io_acct(io); 628 free_io(md, io); 629 630 if (io_error == DM_ENDIO_REQUEUE) 631 return; 632 633 if ((bio->bi_rw & REQ_FLUSH) && bio->bi_size) { 634 /* 635 * Preflush done for flush with data, reissue 636 * without REQ_FLUSH. 637 */ 638 bio->bi_rw &= ~REQ_FLUSH; 639 queue_io(md, bio); 640 } else { 641 /* done with normal IO or empty flush */ 642 trace_block_bio_complete(md->queue, bio, io_error); 643 bio_endio(bio, io_error); 644 } 645 } 646 } 647 648 static void clone_endio(struct bio *bio, int error) 649 { 650 int r = 0; 651 struct dm_target_io *tio = bio->bi_private; 652 struct dm_io *io = tio->io; 653 struct mapped_device *md = tio->io->md; 654 dm_endio_fn endio = tio->ti->type->end_io; 655 656 if (!bio_flagged(bio, BIO_UPTODATE) && !error) 657 error = -EIO; 658 659 if (endio) { 660 r = endio(tio->ti, bio, error, &tio->info); 661 if (r < 0 || r == DM_ENDIO_REQUEUE) 662 /* 663 * error and requeue request are handled 664 * in dec_pending(). 665 */ 666 error = r; 667 else if (r == DM_ENDIO_INCOMPLETE) 668 /* The target will handle the io */ 669 return; 670 else if (r) { 671 DMWARN("unimplemented target endio return value: %d", r); 672 BUG(); 673 } 674 } 675 676 free_tio(md, tio); 677 dec_pending(io, error); 678 } 679 680 /* 681 * Partial completion handling for request-based dm 682 */ 683 static void end_clone_bio(struct bio *clone, int error) 684 { 685 struct dm_rq_clone_bio_info *info = clone->bi_private; 686 struct dm_rq_target_io *tio = info->tio; 687 struct bio *bio = info->orig; 688 unsigned int nr_bytes = info->orig->bi_size; 689 690 bio_put(clone); 691 692 if (tio->error) 693 /* 694 * An error has already been detected on the request. 695 * Once error occurred, just let clone->end_io() handle 696 * the remainder. 697 */ 698 return; 699 else if (error) { 700 /* 701 * Don't notice the error to the upper layer yet. 702 * The error handling decision is made by the target driver, 703 * when the request is completed. 704 */ 705 tio->error = error; 706 return; 707 } 708 709 /* 710 * I/O for the bio successfully completed. 711 * Notice the data completion to the upper layer. 712 */ 713 714 /* 715 * bios are processed from the head of the list. 716 * So the completing bio should always be rq->bio. 717 * If it's not, something wrong is happening. 718 */ 719 if (tio->orig->bio != bio) 720 DMERR("bio completion is going in the middle of the request"); 721 722 /* 723 * Update the original request. 724 * Do not use blk_end_request() here, because it may complete 725 * the original request before the clone, and break the ordering. 726 */ 727 blk_update_request(tio->orig, 0, nr_bytes); 728 } 729 730 /* 731 * Don't touch any member of the md after calling this function because 732 * the md may be freed in dm_put() at the end of this function. 733 * Or do dm_get() before calling this function and dm_put() later. 734 */ 735 static void rq_completed(struct mapped_device *md, int rw, int run_queue) 736 { 737 atomic_dec(&md->pending[rw]); 738 739 /* nudge anyone waiting on suspend queue */ 740 if (!md_in_flight(md)) 741 wake_up(&md->wait); 742 743 /* 744 * Run this off this callpath, as drivers could invoke end_io while 745 * inside their request_fn (and holding the queue lock). Calling 746 * back into ->request_fn() could deadlock attempting to grab the 747 * queue lock again. 748 */ 749 if (run_queue) 750 blk_run_queue_async(md->queue); 751 752 /* 753 * dm_put() must be at the end of this function. See the comment above 754 */ 755 dm_put(md); 756 } 757 758 static void free_rq_clone(struct request *clone) 759 { 760 struct dm_rq_target_io *tio = clone->end_io_data; 761 762 blk_rq_unprep_clone(clone); 763 free_rq_tio(tio); 764 } 765 766 /* 767 * Complete the clone and the original request. 768 * Must be called without queue lock. 769 */ 770 static void dm_end_request(struct request *clone, int error) 771 { 772 int rw = rq_data_dir(clone); 773 struct dm_rq_target_io *tio = clone->end_io_data; 774 struct mapped_device *md = tio->md; 775 struct request *rq = tio->orig; 776 777 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { 778 rq->errors = clone->errors; 779 rq->resid_len = clone->resid_len; 780 781 if (rq->sense) 782 /* 783 * We are using the sense buffer of the original 784 * request. 785 * So setting the length of the sense data is enough. 786 */ 787 rq->sense_len = clone->sense_len; 788 } 789 790 free_rq_clone(clone); 791 blk_end_request_all(rq, error); 792 rq_completed(md, rw, true); 793 } 794 795 static void dm_unprep_request(struct request *rq) 796 { 797 struct request *clone = rq->special; 798 799 rq->special = NULL; 800 rq->cmd_flags &= ~REQ_DONTPREP; 801 802 free_rq_clone(clone); 803 } 804 805 /* 806 * Requeue the original request of a clone. 807 */ 808 void dm_requeue_unmapped_request(struct request *clone) 809 { 810 int rw = rq_data_dir(clone); 811 struct dm_rq_target_io *tio = clone->end_io_data; 812 struct mapped_device *md = tio->md; 813 struct request *rq = tio->orig; 814 struct request_queue *q = rq->q; 815 unsigned long flags; 816 817 dm_unprep_request(rq); 818 819 spin_lock_irqsave(q->queue_lock, flags); 820 blk_requeue_request(q, rq); 821 spin_unlock_irqrestore(q->queue_lock, flags); 822 823 rq_completed(md, rw, 0); 824 } 825 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request); 826 827 static void __stop_queue(struct request_queue *q) 828 { 829 blk_stop_queue(q); 830 } 831 832 static void stop_queue(struct request_queue *q) 833 { 834 unsigned long flags; 835 836 spin_lock_irqsave(q->queue_lock, flags); 837 __stop_queue(q); 838 spin_unlock_irqrestore(q->queue_lock, flags); 839 } 840 841 static void __start_queue(struct request_queue *q) 842 { 843 if (blk_queue_stopped(q)) 844 blk_start_queue(q); 845 } 846 847 static void start_queue(struct request_queue *q) 848 { 849 unsigned long flags; 850 851 spin_lock_irqsave(q->queue_lock, flags); 852 __start_queue(q); 853 spin_unlock_irqrestore(q->queue_lock, flags); 854 } 855 856 static void dm_done(struct request *clone, int error, bool mapped) 857 { 858 int r = error; 859 struct dm_rq_target_io *tio = clone->end_io_data; 860 dm_request_endio_fn rq_end_io = NULL; 861 862 if (tio->ti) { 863 rq_end_io = tio->ti->type->rq_end_io; 864 865 if (mapped && rq_end_io) 866 r = rq_end_io(tio->ti, clone, error, &tio->info); 867 } 868 869 if (r <= 0) 870 /* The target wants to complete the I/O */ 871 dm_end_request(clone, r); 872 else if (r == DM_ENDIO_INCOMPLETE) 873 /* The target will handle the I/O */ 874 return; 875 else if (r == DM_ENDIO_REQUEUE) 876 /* The target wants to requeue the I/O */ 877 dm_requeue_unmapped_request(clone); 878 else { 879 DMWARN("unimplemented target endio return value: %d", r); 880 BUG(); 881 } 882 } 883 884 /* 885 * Request completion handler for request-based dm 886 */ 887 static void dm_softirq_done(struct request *rq) 888 { 889 bool mapped = true; 890 struct request *clone = rq->completion_data; 891 struct dm_rq_target_io *tio = clone->end_io_data; 892 893 if (rq->cmd_flags & REQ_FAILED) 894 mapped = false; 895 896 dm_done(clone, tio->error, mapped); 897 } 898 899 /* 900 * Complete the clone and the original request with the error status 901 * through softirq context. 902 */ 903 static void dm_complete_request(struct request *clone, int error) 904 { 905 struct dm_rq_target_io *tio = clone->end_io_data; 906 struct request *rq = tio->orig; 907 908 tio->error = error; 909 rq->completion_data = clone; 910 blk_complete_request(rq); 911 } 912 913 /* 914 * Complete the not-mapped clone and the original request with the error status 915 * through softirq context. 916 * Target's rq_end_io() function isn't called. 917 * This may be used when the target's map_rq() function fails. 918 */ 919 void dm_kill_unmapped_request(struct request *clone, int error) 920 { 921 struct dm_rq_target_io *tio = clone->end_io_data; 922 struct request *rq = tio->orig; 923 924 rq->cmd_flags |= REQ_FAILED; 925 dm_complete_request(clone, error); 926 } 927 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request); 928 929 /* 930 * Called with the queue lock held 931 */ 932 static void end_clone_request(struct request *clone, int error) 933 { 934 /* 935 * For just cleaning up the information of the queue in which 936 * the clone was dispatched. 937 * The clone is *NOT* freed actually here because it is alloced from 938 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags. 939 */ 940 __blk_put_request(clone->q, clone); 941 942 /* 943 * Actual request completion is done in a softirq context which doesn't 944 * hold the queue lock. Otherwise, deadlock could occur because: 945 * - another request may be submitted by the upper level driver 946 * of the stacking during the completion 947 * - the submission which requires queue lock may be done 948 * against this queue 949 */ 950 dm_complete_request(clone, error); 951 } 952 953 /* 954 * Return maximum size of I/O possible at the supplied sector up to the current 955 * target boundary. 956 */ 957 static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti) 958 { 959 sector_t target_offset = dm_target_offset(ti, sector); 960 961 return ti->len - target_offset; 962 } 963 964 static sector_t max_io_len(sector_t sector, struct dm_target *ti) 965 { 966 sector_t len = max_io_len_target_boundary(sector, ti); 967 sector_t offset, max_len; 968 969 /* 970 * Does the target need to split even further? 971 */ 972 if (ti->max_io_len) { 973 offset = dm_target_offset(ti, sector); 974 if (unlikely(ti->max_io_len & (ti->max_io_len - 1))) 975 max_len = sector_div(offset, ti->max_io_len); 976 else 977 max_len = offset & (ti->max_io_len - 1); 978 max_len = ti->max_io_len - max_len; 979 980 if (len > max_len) 981 len = max_len; 982 } 983 984 return len; 985 } 986 987 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len) 988 { 989 if (len > UINT_MAX) { 990 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)", 991 (unsigned long long)len, UINT_MAX); 992 ti->error = "Maximum size of target IO is too large"; 993 return -EINVAL; 994 } 995 996 ti->max_io_len = (uint32_t) len; 997 998 return 0; 999 } 1000 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len); 1001 1002 static void __map_bio(struct dm_target *ti, struct dm_target_io *tio) 1003 { 1004 int r; 1005 sector_t sector; 1006 struct mapped_device *md; 1007 struct bio *clone = &tio->clone; 1008 1009 clone->bi_end_io = clone_endio; 1010 clone->bi_private = tio; 1011 1012 /* 1013 * Map the clone. If r == 0 we don't need to do 1014 * anything, the target has assumed ownership of 1015 * this io. 1016 */ 1017 atomic_inc(&tio->io->io_count); 1018 sector = clone->bi_sector; 1019 r = ti->type->map(ti, clone, &tio->info); 1020 if (r == DM_MAPIO_REMAPPED) { 1021 /* the bio has been remapped so dispatch it */ 1022 1023 trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone, 1024 tio->io->bio->bi_bdev->bd_dev, sector); 1025 1026 generic_make_request(clone); 1027 } else if (r < 0 || r == DM_MAPIO_REQUEUE) { 1028 /* error the io and bail out, or requeue it if needed */ 1029 md = tio->io->md; 1030 dec_pending(tio->io, r); 1031 free_tio(md, tio); 1032 } else if (r) { 1033 DMWARN("unimplemented target map return value: %d", r); 1034 BUG(); 1035 } 1036 } 1037 1038 struct clone_info { 1039 struct mapped_device *md; 1040 struct dm_table *map; 1041 struct bio *bio; 1042 struct dm_io *io; 1043 sector_t sector; 1044 sector_t sector_count; 1045 unsigned short idx; 1046 }; 1047 1048 /* 1049 * Creates a little bio that just does part of a bvec. 1050 */ 1051 static void split_bvec(struct dm_target_io *tio, struct bio *bio, 1052 sector_t sector, unsigned short idx, unsigned int offset, 1053 unsigned int len, struct bio_set *bs) 1054 { 1055 struct bio *clone = &tio->clone; 1056 struct bio_vec *bv = bio->bi_io_vec + idx; 1057 1058 *clone->bi_io_vec = *bv; 1059 1060 clone->bi_sector = sector; 1061 clone->bi_bdev = bio->bi_bdev; 1062 clone->bi_rw = bio->bi_rw; 1063 clone->bi_vcnt = 1; 1064 clone->bi_size = to_bytes(len); 1065 clone->bi_io_vec->bv_offset = offset; 1066 clone->bi_io_vec->bv_len = clone->bi_size; 1067 clone->bi_flags |= 1 << BIO_CLONED; 1068 1069 if (bio_integrity(bio)) { 1070 bio_integrity_clone(clone, bio, GFP_NOIO); 1071 bio_integrity_trim(clone, 1072 bio_sector_offset(bio, idx, offset), len); 1073 } 1074 } 1075 1076 /* 1077 * Creates a bio that consists of range of complete bvecs. 1078 */ 1079 static void clone_bio(struct dm_target_io *tio, struct bio *bio, 1080 sector_t sector, unsigned short idx, 1081 unsigned short bv_count, unsigned int len, 1082 struct bio_set *bs) 1083 { 1084 struct bio *clone = &tio->clone; 1085 1086 __bio_clone(clone, bio); 1087 clone->bi_sector = sector; 1088 clone->bi_idx = idx; 1089 clone->bi_vcnt = idx + bv_count; 1090 clone->bi_size = to_bytes(len); 1091 clone->bi_flags &= ~(1 << BIO_SEG_VALID); 1092 1093 if (bio_integrity(bio)) { 1094 bio_integrity_clone(clone, bio, GFP_NOIO); 1095 1096 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size) 1097 bio_integrity_trim(clone, 1098 bio_sector_offset(bio, idx, 0), len); 1099 } 1100 } 1101 1102 static struct dm_target_io *alloc_tio(struct clone_info *ci, 1103 struct dm_target *ti, int nr_iovecs) 1104 { 1105 struct dm_target_io *tio; 1106 struct bio *clone; 1107 1108 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs); 1109 tio = container_of(clone, struct dm_target_io, clone); 1110 1111 tio->io = ci->io; 1112 tio->ti = ti; 1113 memset(&tio->info, 0, sizeof(tio->info)); 1114 1115 return tio; 1116 } 1117 1118 static void __issue_target_request(struct clone_info *ci, struct dm_target *ti, 1119 unsigned request_nr, sector_t len) 1120 { 1121 struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs); 1122 struct bio *clone = &tio->clone; 1123 1124 tio->info.target_request_nr = request_nr; 1125 1126 /* 1127 * Discard requests require the bio's inline iovecs be initialized. 1128 * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush 1129 * and discard, so no need for concern about wasted bvec allocations. 1130 */ 1131 1132 __bio_clone(clone, ci->bio); 1133 if (len) { 1134 clone->bi_sector = ci->sector; 1135 clone->bi_size = to_bytes(len); 1136 } 1137 1138 __map_bio(ti, tio); 1139 } 1140 1141 static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti, 1142 unsigned num_requests, sector_t len) 1143 { 1144 unsigned request_nr; 1145 1146 for (request_nr = 0; request_nr < num_requests; request_nr++) 1147 __issue_target_request(ci, ti, request_nr, len); 1148 } 1149 1150 static int __clone_and_map_empty_flush(struct clone_info *ci) 1151 { 1152 unsigned target_nr = 0; 1153 struct dm_target *ti; 1154 1155 BUG_ON(bio_has_data(ci->bio)); 1156 while ((ti = dm_table_get_target(ci->map, target_nr++))) 1157 __issue_target_requests(ci, ti, ti->num_flush_requests, 0); 1158 1159 return 0; 1160 } 1161 1162 /* 1163 * Perform all io with a single clone. 1164 */ 1165 static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti) 1166 { 1167 struct bio *bio = ci->bio; 1168 struct dm_target_io *tio; 1169 1170 tio = alloc_tio(ci, ti, bio->bi_max_vecs); 1171 clone_bio(tio, bio, ci->sector, ci->idx, bio->bi_vcnt - ci->idx, 1172 ci->sector_count, ci->md->bs); 1173 __map_bio(ti, tio); 1174 ci->sector_count = 0; 1175 } 1176 1177 static int __clone_and_map_discard(struct clone_info *ci) 1178 { 1179 struct dm_target *ti; 1180 sector_t len; 1181 1182 do { 1183 ti = dm_table_find_target(ci->map, ci->sector); 1184 if (!dm_target_is_valid(ti)) 1185 return -EIO; 1186 1187 /* 1188 * Even though the device advertised discard support, 1189 * that does not mean every target supports it, and 1190 * reconfiguration might also have changed that since the 1191 * check was performed. 1192 */ 1193 if (!ti->num_discard_requests) 1194 return -EOPNOTSUPP; 1195 1196 if (!ti->split_discard_requests) 1197 len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); 1198 else 1199 len = min(ci->sector_count, max_io_len(ci->sector, ti)); 1200 1201 __issue_target_requests(ci, ti, ti->num_discard_requests, len); 1202 1203 ci->sector += len; 1204 } while (ci->sector_count -= len); 1205 1206 return 0; 1207 } 1208 1209 static int __clone_and_map(struct clone_info *ci) 1210 { 1211 struct bio *bio = ci->bio; 1212 struct dm_target *ti; 1213 sector_t len = 0, max; 1214 struct dm_target_io *tio; 1215 1216 if (unlikely(bio->bi_rw & REQ_DISCARD)) 1217 return __clone_and_map_discard(ci); 1218 1219 ti = dm_table_find_target(ci->map, ci->sector); 1220 if (!dm_target_is_valid(ti)) 1221 return -EIO; 1222 1223 max = max_io_len(ci->sector, ti); 1224 1225 if (ci->sector_count <= max) { 1226 /* 1227 * Optimise for the simple case where we can do all of 1228 * the remaining io with a single clone. 1229 */ 1230 __clone_and_map_simple(ci, ti); 1231 1232 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { 1233 /* 1234 * There are some bvecs that don't span targets. 1235 * Do as many of these as possible. 1236 */ 1237 int i; 1238 sector_t remaining = max; 1239 sector_t bv_len; 1240 1241 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { 1242 bv_len = to_sector(bio->bi_io_vec[i].bv_len); 1243 1244 if (bv_len > remaining) 1245 break; 1246 1247 remaining -= bv_len; 1248 len += bv_len; 1249 } 1250 1251 tio = alloc_tio(ci, ti, bio->bi_max_vecs); 1252 clone_bio(tio, bio, ci->sector, ci->idx, i - ci->idx, len, 1253 ci->md->bs); 1254 __map_bio(ti, tio); 1255 1256 ci->sector += len; 1257 ci->sector_count -= len; 1258 ci->idx = i; 1259 1260 } else { 1261 /* 1262 * Handle a bvec that must be split between two or more targets. 1263 */ 1264 struct bio_vec *bv = bio->bi_io_vec + ci->idx; 1265 sector_t remaining = to_sector(bv->bv_len); 1266 unsigned int offset = 0; 1267 1268 do { 1269 if (offset) { 1270 ti = dm_table_find_target(ci->map, ci->sector); 1271 if (!dm_target_is_valid(ti)) 1272 return -EIO; 1273 1274 max = max_io_len(ci->sector, ti); 1275 } 1276 1277 len = min(remaining, max); 1278 1279 tio = alloc_tio(ci, ti, 1); 1280 split_bvec(tio, bio, ci->sector, ci->idx, 1281 bv->bv_offset + offset, len, ci->md->bs); 1282 1283 __map_bio(ti, tio); 1284 1285 ci->sector += len; 1286 ci->sector_count -= len; 1287 offset += to_bytes(len); 1288 } while (remaining -= len); 1289 1290 ci->idx++; 1291 } 1292 1293 return 0; 1294 } 1295 1296 /* 1297 * Split the bio into several clones and submit it to targets. 1298 */ 1299 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio) 1300 { 1301 struct clone_info ci; 1302 int error = 0; 1303 1304 ci.map = dm_get_live_table(md); 1305 if (unlikely(!ci.map)) { 1306 bio_io_error(bio); 1307 return; 1308 } 1309 1310 ci.md = md; 1311 ci.io = alloc_io(md); 1312 ci.io->error = 0; 1313 atomic_set(&ci.io->io_count, 1); 1314 ci.io->bio = bio; 1315 ci.io->md = md; 1316 spin_lock_init(&ci.io->endio_lock); 1317 ci.sector = bio->bi_sector; 1318 ci.idx = bio->bi_idx; 1319 1320 start_io_acct(ci.io); 1321 if (bio->bi_rw & REQ_FLUSH) { 1322 ci.bio = &ci.md->flush_bio; 1323 ci.sector_count = 0; 1324 error = __clone_and_map_empty_flush(&ci); 1325 /* dec_pending submits any data associated with flush */ 1326 } else { 1327 ci.bio = bio; 1328 ci.sector_count = bio_sectors(bio); 1329 while (ci.sector_count && !error) 1330 error = __clone_and_map(&ci); 1331 } 1332 1333 /* drop the extra reference count */ 1334 dec_pending(ci.io, error); 1335 dm_table_put(ci.map); 1336 } 1337 /*----------------------------------------------------------------- 1338 * CRUD END 1339 *---------------------------------------------------------------*/ 1340 1341 static int dm_merge_bvec(struct request_queue *q, 1342 struct bvec_merge_data *bvm, 1343 struct bio_vec *biovec) 1344 { 1345 struct mapped_device *md = q->queuedata; 1346 struct dm_table *map = dm_get_live_table(md); 1347 struct dm_target *ti; 1348 sector_t max_sectors; 1349 int max_size = 0; 1350 1351 if (unlikely(!map)) 1352 goto out; 1353 1354 ti = dm_table_find_target(map, bvm->bi_sector); 1355 if (!dm_target_is_valid(ti)) 1356 goto out_table; 1357 1358 /* 1359 * Find maximum amount of I/O that won't need splitting 1360 */ 1361 max_sectors = min(max_io_len(bvm->bi_sector, ti), 1362 (sector_t) BIO_MAX_SECTORS); 1363 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; 1364 if (max_size < 0) 1365 max_size = 0; 1366 1367 /* 1368 * merge_bvec_fn() returns number of bytes 1369 * it can accept at this offset 1370 * max is precomputed maximal io size 1371 */ 1372 if (max_size && ti->type->merge) 1373 max_size = ti->type->merge(ti, bvm, biovec, max_size); 1374 /* 1375 * If the target doesn't support merge method and some of the devices 1376 * provided their merge_bvec method (we know this by looking at 1377 * queue_max_hw_sectors), then we can't allow bios with multiple vector 1378 * entries. So always set max_size to 0, and the code below allows 1379 * just one page. 1380 */ 1381 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) 1382 1383 max_size = 0; 1384 1385 out_table: 1386 dm_table_put(map); 1387 1388 out: 1389 /* 1390 * Always allow an entire first page 1391 */ 1392 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) 1393 max_size = biovec->bv_len; 1394 1395 return max_size; 1396 } 1397 1398 /* 1399 * The request function that just remaps the bio built up by 1400 * dm_merge_bvec. 1401 */ 1402 static void _dm_request(struct request_queue *q, struct bio *bio) 1403 { 1404 int rw = bio_data_dir(bio); 1405 struct mapped_device *md = q->queuedata; 1406 int cpu; 1407 1408 down_read(&md->io_lock); 1409 1410 cpu = part_stat_lock(); 1411 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]); 1412 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio)); 1413 part_stat_unlock(); 1414 1415 /* if we're suspended, we have to queue this io for later */ 1416 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) { 1417 up_read(&md->io_lock); 1418 1419 if (bio_rw(bio) != READA) 1420 queue_io(md, bio); 1421 else 1422 bio_io_error(bio); 1423 return; 1424 } 1425 1426 __split_and_process_bio(md, bio); 1427 up_read(&md->io_lock); 1428 return; 1429 } 1430 1431 static int dm_request_based(struct mapped_device *md) 1432 { 1433 return blk_queue_stackable(md->queue); 1434 } 1435 1436 static void dm_request(struct request_queue *q, struct bio *bio) 1437 { 1438 struct mapped_device *md = q->queuedata; 1439 1440 if (dm_request_based(md)) 1441 blk_queue_bio(q, bio); 1442 else 1443 _dm_request(q, bio); 1444 } 1445 1446 void dm_dispatch_request(struct request *rq) 1447 { 1448 int r; 1449 1450 if (blk_queue_io_stat(rq->q)) 1451 rq->cmd_flags |= REQ_IO_STAT; 1452 1453 rq->start_time = jiffies; 1454 r = blk_insert_cloned_request(rq->q, rq); 1455 if (r) 1456 dm_complete_request(rq, r); 1457 } 1458 EXPORT_SYMBOL_GPL(dm_dispatch_request); 1459 1460 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, 1461 void *data) 1462 { 1463 struct dm_rq_target_io *tio = data; 1464 struct dm_rq_clone_bio_info *info = 1465 container_of(bio, struct dm_rq_clone_bio_info, clone); 1466 1467 info->orig = bio_orig; 1468 info->tio = tio; 1469 bio->bi_end_io = end_clone_bio; 1470 bio->bi_private = info; 1471 1472 return 0; 1473 } 1474 1475 static int setup_clone(struct request *clone, struct request *rq, 1476 struct dm_rq_target_io *tio) 1477 { 1478 int r; 1479 1480 r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC, 1481 dm_rq_bio_constructor, tio); 1482 if (r) 1483 return r; 1484 1485 clone->cmd = rq->cmd; 1486 clone->cmd_len = rq->cmd_len; 1487 clone->sense = rq->sense; 1488 clone->buffer = rq->buffer; 1489 clone->end_io = end_clone_request; 1490 clone->end_io_data = tio; 1491 1492 return 0; 1493 } 1494 1495 static struct request *clone_rq(struct request *rq, struct mapped_device *md, 1496 gfp_t gfp_mask) 1497 { 1498 struct request *clone; 1499 struct dm_rq_target_io *tio; 1500 1501 tio = alloc_rq_tio(md, gfp_mask); 1502 if (!tio) 1503 return NULL; 1504 1505 tio->md = md; 1506 tio->ti = NULL; 1507 tio->orig = rq; 1508 tio->error = 0; 1509 memset(&tio->info, 0, sizeof(tio->info)); 1510 1511 clone = &tio->clone; 1512 if (setup_clone(clone, rq, tio)) { 1513 /* -ENOMEM */ 1514 free_rq_tio(tio); 1515 return NULL; 1516 } 1517 1518 return clone; 1519 } 1520 1521 /* 1522 * Called with the queue lock held. 1523 */ 1524 static int dm_prep_fn(struct request_queue *q, struct request *rq) 1525 { 1526 struct mapped_device *md = q->queuedata; 1527 struct request *clone; 1528 1529 if (unlikely(rq->special)) { 1530 DMWARN("Already has something in rq->special."); 1531 return BLKPREP_KILL; 1532 } 1533 1534 clone = clone_rq(rq, md, GFP_ATOMIC); 1535 if (!clone) 1536 return BLKPREP_DEFER; 1537 1538 rq->special = clone; 1539 rq->cmd_flags |= REQ_DONTPREP; 1540 1541 return BLKPREP_OK; 1542 } 1543 1544 /* 1545 * Returns: 1546 * 0 : the request has been processed (not requeued) 1547 * !0 : the request has been requeued 1548 */ 1549 static int map_request(struct dm_target *ti, struct request *clone, 1550 struct mapped_device *md) 1551 { 1552 int r, requeued = 0; 1553 struct dm_rq_target_io *tio = clone->end_io_data; 1554 1555 tio->ti = ti; 1556 r = ti->type->map_rq(ti, clone, &tio->info); 1557 switch (r) { 1558 case DM_MAPIO_SUBMITTED: 1559 /* The target has taken the I/O to submit by itself later */ 1560 break; 1561 case DM_MAPIO_REMAPPED: 1562 /* The target has remapped the I/O so dispatch it */ 1563 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), 1564 blk_rq_pos(tio->orig)); 1565 dm_dispatch_request(clone); 1566 break; 1567 case DM_MAPIO_REQUEUE: 1568 /* The target wants to requeue the I/O */ 1569 dm_requeue_unmapped_request(clone); 1570 requeued = 1; 1571 break; 1572 default: 1573 if (r > 0) { 1574 DMWARN("unimplemented target map return value: %d", r); 1575 BUG(); 1576 } 1577 1578 /* The target wants to complete the I/O */ 1579 dm_kill_unmapped_request(clone, r); 1580 break; 1581 } 1582 1583 return requeued; 1584 } 1585 1586 static struct request *dm_start_request(struct mapped_device *md, struct request *orig) 1587 { 1588 struct request *clone; 1589 1590 blk_start_request(orig); 1591 clone = orig->special; 1592 atomic_inc(&md->pending[rq_data_dir(clone)]); 1593 1594 /* 1595 * Hold the md reference here for the in-flight I/O. 1596 * We can't rely on the reference count by device opener, 1597 * because the device may be closed during the request completion 1598 * when all bios are completed. 1599 * See the comment in rq_completed() too. 1600 */ 1601 dm_get(md); 1602 1603 return clone; 1604 } 1605 1606 /* 1607 * q->request_fn for request-based dm. 1608 * Called with the queue lock held. 1609 */ 1610 static void dm_request_fn(struct request_queue *q) 1611 { 1612 struct mapped_device *md = q->queuedata; 1613 struct dm_table *map = dm_get_live_table(md); 1614 struct dm_target *ti; 1615 struct request *rq, *clone; 1616 sector_t pos; 1617 1618 /* 1619 * For suspend, check blk_queue_stopped() and increment 1620 * ->pending within a single queue_lock not to increment the 1621 * number of in-flight I/Os after the queue is stopped in 1622 * dm_suspend(). 1623 */ 1624 while (!blk_queue_stopped(q)) { 1625 rq = blk_peek_request(q); 1626 if (!rq) 1627 goto delay_and_out; 1628 1629 /* always use block 0 to find the target for flushes for now */ 1630 pos = 0; 1631 if (!(rq->cmd_flags & REQ_FLUSH)) 1632 pos = blk_rq_pos(rq); 1633 1634 ti = dm_table_find_target(map, pos); 1635 if (!dm_target_is_valid(ti)) { 1636 /* 1637 * Must perform setup, that dm_done() requires, 1638 * before calling dm_kill_unmapped_request 1639 */ 1640 DMERR_LIMIT("request attempted access beyond the end of device"); 1641 clone = dm_start_request(md, rq); 1642 dm_kill_unmapped_request(clone, -EIO); 1643 continue; 1644 } 1645 1646 if (ti->type->busy && ti->type->busy(ti)) 1647 goto delay_and_out; 1648 1649 clone = dm_start_request(md, rq); 1650 1651 spin_unlock(q->queue_lock); 1652 if (map_request(ti, clone, md)) 1653 goto requeued; 1654 1655 BUG_ON(!irqs_disabled()); 1656 spin_lock(q->queue_lock); 1657 } 1658 1659 goto out; 1660 1661 requeued: 1662 BUG_ON(!irqs_disabled()); 1663 spin_lock(q->queue_lock); 1664 1665 delay_and_out: 1666 blk_delay_queue(q, HZ / 10); 1667 out: 1668 dm_table_put(map); 1669 } 1670 1671 int dm_underlying_device_busy(struct request_queue *q) 1672 { 1673 return blk_lld_busy(q); 1674 } 1675 EXPORT_SYMBOL_GPL(dm_underlying_device_busy); 1676 1677 static int dm_lld_busy(struct request_queue *q) 1678 { 1679 int r; 1680 struct mapped_device *md = q->queuedata; 1681 struct dm_table *map = dm_get_live_table(md); 1682 1683 if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) 1684 r = 1; 1685 else 1686 r = dm_table_any_busy_target(map); 1687 1688 dm_table_put(map); 1689 1690 return r; 1691 } 1692 1693 static int dm_any_congested(void *congested_data, int bdi_bits) 1694 { 1695 int r = bdi_bits; 1696 struct mapped_device *md = congested_data; 1697 struct dm_table *map; 1698 1699 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { 1700 map = dm_get_live_table(md); 1701 if (map) { 1702 /* 1703 * Request-based dm cares about only own queue for 1704 * the query about congestion status of request_queue 1705 */ 1706 if (dm_request_based(md)) 1707 r = md->queue->backing_dev_info.state & 1708 bdi_bits; 1709 else 1710 r = dm_table_any_congested(map, bdi_bits); 1711 1712 dm_table_put(map); 1713 } 1714 } 1715 1716 return r; 1717 } 1718 1719 /*----------------------------------------------------------------- 1720 * An IDR is used to keep track of allocated minor numbers. 1721 *---------------------------------------------------------------*/ 1722 static void free_minor(int minor) 1723 { 1724 spin_lock(&_minor_lock); 1725 idr_remove(&_minor_idr, minor); 1726 spin_unlock(&_minor_lock); 1727 } 1728 1729 /* 1730 * See if the device with a specific minor # is free. 1731 */ 1732 static int specific_minor(int minor) 1733 { 1734 int r, m; 1735 1736 if (minor >= (1 << MINORBITS)) 1737 return -EINVAL; 1738 1739 r = idr_pre_get(&_minor_idr, GFP_KERNEL); 1740 if (!r) 1741 return -ENOMEM; 1742 1743 spin_lock(&_minor_lock); 1744 1745 if (idr_find(&_minor_idr, minor)) { 1746 r = -EBUSY; 1747 goto out; 1748 } 1749 1750 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); 1751 if (r) 1752 goto out; 1753 1754 if (m != minor) { 1755 idr_remove(&_minor_idr, m); 1756 r = -EBUSY; 1757 goto out; 1758 } 1759 1760 out: 1761 spin_unlock(&_minor_lock); 1762 return r; 1763 } 1764 1765 static int next_free_minor(int *minor) 1766 { 1767 int r, m; 1768 1769 r = idr_pre_get(&_minor_idr, GFP_KERNEL); 1770 if (!r) 1771 return -ENOMEM; 1772 1773 spin_lock(&_minor_lock); 1774 1775 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); 1776 if (r) 1777 goto out; 1778 1779 if (m >= (1 << MINORBITS)) { 1780 idr_remove(&_minor_idr, m); 1781 r = -ENOSPC; 1782 goto out; 1783 } 1784 1785 *minor = m; 1786 1787 out: 1788 spin_unlock(&_minor_lock); 1789 return r; 1790 } 1791 1792 static const struct block_device_operations dm_blk_dops; 1793 1794 static void dm_wq_work(struct work_struct *work); 1795 1796 static void dm_init_md_queue(struct mapped_device *md) 1797 { 1798 /* 1799 * Request-based dm devices cannot be stacked on top of bio-based dm 1800 * devices. The type of this dm device has not been decided yet. 1801 * The type is decided at the first table loading time. 1802 * To prevent problematic device stacking, clear the queue flag 1803 * for request stacking support until then. 1804 * 1805 * This queue is new, so no concurrency on the queue_flags. 1806 */ 1807 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue); 1808 1809 md->queue->queuedata = md; 1810 md->queue->backing_dev_info.congested_fn = dm_any_congested; 1811 md->queue->backing_dev_info.congested_data = md; 1812 blk_queue_make_request(md->queue, dm_request); 1813 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); 1814 blk_queue_merge_bvec(md->queue, dm_merge_bvec); 1815 } 1816 1817 /* 1818 * Allocate and initialise a blank device with a given minor. 1819 */ 1820 static struct mapped_device *alloc_dev(int minor) 1821 { 1822 int r; 1823 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL); 1824 void *old_md; 1825 1826 if (!md) { 1827 DMWARN("unable to allocate device, out of memory."); 1828 return NULL; 1829 } 1830 1831 if (!try_module_get(THIS_MODULE)) 1832 goto bad_module_get; 1833 1834 /* get a minor number for the dev */ 1835 if (minor == DM_ANY_MINOR) 1836 r = next_free_minor(&minor); 1837 else 1838 r = specific_minor(minor); 1839 if (r < 0) 1840 goto bad_minor; 1841 1842 md->type = DM_TYPE_NONE; 1843 init_rwsem(&md->io_lock); 1844 mutex_init(&md->suspend_lock); 1845 mutex_init(&md->type_lock); 1846 spin_lock_init(&md->deferred_lock); 1847 rwlock_init(&md->map_lock); 1848 atomic_set(&md->holders, 1); 1849 atomic_set(&md->open_count, 0); 1850 atomic_set(&md->event_nr, 0); 1851 atomic_set(&md->uevent_seq, 0); 1852 INIT_LIST_HEAD(&md->uevent_list); 1853 spin_lock_init(&md->uevent_lock); 1854 1855 md->queue = blk_alloc_queue(GFP_KERNEL); 1856 if (!md->queue) 1857 goto bad_queue; 1858 1859 dm_init_md_queue(md); 1860 1861 md->disk = alloc_disk(1); 1862 if (!md->disk) 1863 goto bad_disk; 1864 1865 atomic_set(&md->pending[0], 0); 1866 atomic_set(&md->pending[1], 0); 1867 init_waitqueue_head(&md->wait); 1868 INIT_WORK(&md->work, dm_wq_work); 1869 init_waitqueue_head(&md->eventq); 1870 1871 md->disk->major = _major; 1872 md->disk->first_minor = minor; 1873 md->disk->fops = &dm_blk_dops; 1874 md->disk->queue = md->queue; 1875 md->disk->private_data = md; 1876 sprintf(md->disk->disk_name, "dm-%d", minor); 1877 add_disk(md->disk); 1878 format_dev_t(md->name, MKDEV(_major, minor)); 1879 1880 md->wq = alloc_workqueue("kdmflush", 1881 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0); 1882 if (!md->wq) 1883 goto bad_thread; 1884 1885 md->bdev = bdget_disk(md->disk, 0); 1886 if (!md->bdev) 1887 goto bad_bdev; 1888 1889 bio_init(&md->flush_bio); 1890 md->flush_bio.bi_bdev = md->bdev; 1891 md->flush_bio.bi_rw = WRITE_FLUSH; 1892 1893 /* Populate the mapping, nobody knows we exist yet */ 1894 spin_lock(&_minor_lock); 1895 old_md = idr_replace(&_minor_idr, md, minor); 1896 spin_unlock(&_minor_lock); 1897 1898 BUG_ON(old_md != MINOR_ALLOCED); 1899 1900 return md; 1901 1902 bad_bdev: 1903 destroy_workqueue(md->wq); 1904 bad_thread: 1905 del_gendisk(md->disk); 1906 put_disk(md->disk); 1907 bad_disk: 1908 blk_cleanup_queue(md->queue); 1909 bad_queue: 1910 free_minor(minor); 1911 bad_minor: 1912 module_put(THIS_MODULE); 1913 bad_module_get: 1914 kfree(md); 1915 return NULL; 1916 } 1917 1918 static void unlock_fs(struct mapped_device *md); 1919 1920 static void free_dev(struct mapped_device *md) 1921 { 1922 int minor = MINOR(disk_devt(md->disk)); 1923 1924 unlock_fs(md); 1925 bdput(md->bdev); 1926 destroy_workqueue(md->wq); 1927 if (md->tio_pool) 1928 mempool_destroy(md->tio_pool); 1929 if (md->io_pool) 1930 mempool_destroy(md->io_pool); 1931 if (md->bs) 1932 bioset_free(md->bs); 1933 blk_integrity_unregister(md->disk); 1934 del_gendisk(md->disk); 1935 free_minor(minor); 1936 1937 spin_lock(&_minor_lock); 1938 md->disk->private_data = NULL; 1939 spin_unlock(&_minor_lock); 1940 1941 put_disk(md->disk); 1942 blk_cleanup_queue(md->queue); 1943 module_put(THIS_MODULE); 1944 kfree(md); 1945 } 1946 1947 static void __bind_mempools(struct mapped_device *md, struct dm_table *t) 1948 { 1949 struct dm_md_mempools *p; 1950 1951 if (md->io_pool && (md->tio_pool || dm_table_get_type(t) == DM_TYPE_BIO_BASED) && md->bs) 1952 /* the md already has necessary mempools */ 1953 goto out; 1954 1955 p = dm_table_get_md_mempools(t); 1956 BUG_ON(!p || md->io_pool || md->tio_pool || md->bs); 1957 1958 md->io_pool = p->io_pool; 1959 p->io_pool = NULL; 1960 md->tio_pool = p->tio_pool; 1961 p->tio_pool = NULL; 1962 md->bs = p->bs; 1963 p->bs = NULL; 1964 1965 out: 1966 /* mempool bind completed, now no need any mempools in the table */ 1967 dm_table_free_md_mempools(t); 1968 } 1969 1970 /* 1971 * Bind a table to the device. 1972 */ 1973 static void event_callback(void *context) 1974 { 1975 unsigned long flags; 1976 LIST_HEAD(uevents); 1977 struct mapped_device *md = (struct mapped_device *) context; 1978 1979 spin_lock_irqsave(&md->uevent_lock, flags); 1980 list_splice_init(&md->uevent_list, &uevents); 1981 spin_unlock_irqrestore(&md->uevent_lock, flags); 1982 1983 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); 1984 1985 atomic_inc(&md->event_nr); 1986 wake_up(&md->eventq); 1987 } 1988 1989 /* 1990 * Protected by md->suspend_lock obtained by dm_swap_table(). 1991 */ 1992 static void __set_size(struct mapped_device *md, sector_t size) 1993 { 1994 set_capacity(md->disk, size); 1995 1996 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); 1997 } 1998 1999 /* 2000 * Return 1 if the queue has a compulsory merge_bvec_fn function. 2001 * 2002 * If this function returns 0, then the device is either a non-dm 2003 * device without a merge_bvec_fn, or it is a dm device that is 2004 * able to split any bios it receives that are too big. 2005 */ 2006 int dm_queue_merge_is_compulsory(struct request_queue *q) 2007 { 2008 struct mapped_device *dev_md; 2009 2010 if (!q->merge_bvec_fn) 2011 return 0; 2012 2013 if (q->make_request_fn == dm_request) { 2014 dev_md = q->queuedata; 2015 if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags)) 2016 return 0; 2017 } 2018 2019 return 1; 2020 } 2021 2022 static int dm_device_merge_is_compulsory(struct dm_target *ti, 2023 struct dm_dev *dev, sector_t start, 2024 sector_t len, void *data) 2025 { 2026 struct block_device *bdev = dev->bdev; 2027 struct request_queue *q = bdev_get_queue(bdev); 2028 2029 return dm_queue_merge_is_compulsory(q); 2030 } 2031 2032 /* 2033 * Return 1 if it is acceptable to ignore merge_bvec_fn based 2034 * on the properties of the underlying devices. 2035 */ 2036 static int dm_table_merge_is_optional(struct dm_table *table) 2037 { 2038 unsigned i = 0; 2039 struct dm_target *ti; 2040 2041 while (i < dm_table_get_num_targets(table)) { 2042 ti = dm_table_get_target(table, i++); 2043 2044 if (ti->type->iterate_devices && 2045 ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL)) 2046 return 0; 2047 } 2048 2049 return 1; 2050 } 2051 2052 /* 2053 * Returns old map, which caller must destroy. 2054 */ 2055 static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, 2056 struct queue_limits *limits) 2057 { 2058 struct dm_table *old_map; 2059 struct request_queue *q = md->queue; 2060 sector_t size; 2061 unsigned long flags; 2062 int merge_is_optional; 2063 2064 size = dm_table_get_size(t); 2065 2066 /* 2067 * Wipe any geometry if the size of the table changed. 2068 */ 2069 if (size != get_capacity(md->disk)) 2070 memset(&md->geometry, 0, sizeof(md->geometry)); 2071 2072 __set_size(md, size); 2073 2074 dm_table_event_callback(t, event_callback, md); 2075 2076 /* 2077 * The queue hasn't been stopped yet, if the old table type wasn't 2078 * for request-based during suspension. So stop it to prevent 2079 * I/O mapping before resume. 2080 * This must be done before setting the queue restrictions, 2081 * because request-based dm may be run just after the setting. 2082 */ 2083 if (dm_table_request_based(t) && !blk_queue_stopped(q)) 2084 stop_queue(q); 2085 2086 __bind_mempools(md, t); 2087 2088 merge_is_optional = dm_table_merge_is_optional(t); 2089 2090 write_lock_irqsave(&md->map_lock, flags); 2091 old_map = md->map; 2092 md->map = t; 2093 md->immutable_target_type = dm_table_get_immutable_target_type(t); 2094 2095 dm_table_set_restrictions(t, q, limits); 2096 if (merge_is_optional) 2097 set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); 2098 else 2099 clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags); 2100 write_unlock_irqrestore(&md->map_lock, flags); 2101 2102 return old_map; 2103 } 2104 2105 /* 2106 * Returns unbound table for the caller to free. 2107 */ 2108 static struct dm_table *__unbind(struct mapped_device *md) 2109 { 2110 struct dm_table *map = md->map; 2111 unsigned long flags; 2112 2113 if (!map) 2114 return NULL; 2115 2116 dm_table_event_callback(map, NULL, NULL); 2117 write_lock_irqsave(&md->map_lock, flags); 2118 md->map = NULL; 2119 write_unlock_irqrestore(&md->map_lock, flags); 2120 2121 return map; 2122 } 2123 2124 /* 2125 * Constructor for a new device. 2126 */ 2127 int dm_create(int minor, struct mapped_device **result) 2128 { 2129 struct mapped_device *md; 2130 2131 md = alloc_dev(minor); 2132 if (!md) 2133 return -ENXIO; 2134 2135 dm_sysfs_init(md); 2136 2137 *result = md; 2138 return 0; 2139 } 2140 2141 /* 2142 * Functions to manage md->type. 2143 * All are required to hold md->type_lock. 2144 */ 2145 void dm_lock_md_type(struct mapped_device *md) 2146 { 2147 mutex_lock(&md->type_lock); 2148 } 2149 2150 void dm_unlock_md_type(struct mapped_device *md) 2151 { 2152 mutex_unlock(&md->type_lock); 2153 } 2154 2155 void dm_set_md_type(struct mapped_device *md, unsigned type) 2156 { 2157 md->type = type; 2158 } 2159 2160 unsigned dm_get_md_type(struct mapped_device *md) 2161 { 2162 return md->type; 2163 } 2164 2165 struct target_type *dm_get_immutable_target_type(struct mapped_device *md) 2166 { 2167 return md->immutable_target_type; 2168 } 2169 2170 /* 2171 * Fully initialize a request-based queue (->elevator, ->request_fn, etc). 2172 */ 2173 static int dm_init_request_based_queue(struct mapped_device *md) 2174 { 2175 struct request_queue *q = NULL; 2176 2177 if (md->queue->elevator) 2178 return 1; 2179 2180 /* Fully initialize the queue */ 2181 q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL); 2182 if (!q) 2183 return 0; 2184 2185 md->queue = q; 2186 dm_init_md_queue(md); 2187 blk_queue_softirq_done(md->queue, dm_softirq_done); 2188 blk_queue_prep_rq(md->queue, dm_prep_fn); 2189 blk_queue_lld_busy(md->queue, dm_lld_busy); 2190 2191 elv_register_queue(md->queue); 2192 2193 return 1; 2194 } 2195 2196 /* 2197 * Setup the DM device's queue based on md's type 2198 */ 2199 int dm_setup_md_queue(struct mapped_device *md) 2200 { 2201 if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) && 2202 !dm_init_request_based_queue(md)) { 2203 DMWARN("Cannot initialize queue for request-based mapped device"); 2204 return -EINVAL; 2205 } 2206 2207 return 0; 2208 } 2209 2210 static struct mapped_device *dm_find_md(dev_t dev) 2211 { 2212 struct mapped_device *md; 2213 unsigned minor = MINOR(dev); 2214 2215 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) 2216 return NULL; 2217 2218 spin_lock(&_minor_lock); 2219 2220 md = idr_find(&_minor_idr, minor); 2221 if (md && (md == MINOR_ALLOCED || 2222 (MINOR(disk_devt(dm_disk(md))) != minor) || 2223 dm_deleting_md(md) || 2224 test_bit(DMF_FREEING, &md->flags))) { 2225 md = NULL; 2226 goto out; 2227 } 2228 2229 out: 2230 spin_unlock(&_minor_lock); 2231 2232 return md; 2233 } 2234 2235 struct mapped_device *dm_get_md(dev_t dev) 2236 { 2237 struct mapped_device *md = dm_find_md(dev); 2238 2239 if (md) 2240 dm_get(md); 2241 2242 return md; 2243 } 2244 EXPORT_SYMBOL_GPL(dm_get_md); 2245 2246 void *dm_get_mdptr(struct mapped_device *md) 2247 { 2248 return md->interface_ptr; 2249 } 2250 2251 void dm_set_mdptr(struct mapped_device *md, void *ptr) 2252 { 2253 md->interface_ptr = ptr; 2254 } 2255 2256 void dm_get(struct mapped_device *md) 2257 { 2258 atomic_inc(&md->holders); 2259 BUG_ON(test_bit(DMF_FREEING, &md->flags)); 2260 } 2261 2262 const char *dm_device_name(struct mapped_device *md) 2263 { 2264 return md->name; 2265 } 2266 EXPORT_SYMBOL_GPL(dm_device_name); 2267 2268 static void __dm_destroy(struct mapped_device *md, bool wait) 2269 { 2270 struct dm_table *map; 2271 2272 might_sleep(); 2273 2274 spin_lock(&_minor_lock); 2275 map = dm_get_live_table(md); 2276 idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md)))); 2277 set_bit(DMF_FREEING, &md->flags); 2278 spin_unlock(&_minor_lock); 2279 2280 if (!dm_suspended_md(md)) { 2281 dm_table_presuspend_targets(map); 2282 dm_table_postsuspend_targets(map); 2283 } 2284 2285 /* 2286 * Rare, but there may be I/O requests still going to complete, 2287 * for example. Wait for all references to disappear. 2288 * No one should increment the reference count of the mapped_device, 2289 * after the mapped_device state becomes DMF_FREEING. 2290 */ 2291 if (wait) 2292 while (atomic_read(&md->holders)) 2293 msleep(1); 2294 else if (atomic_read(&md->holders)) 2295 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)", 2296 dm_device_name(md), atomic_read(&md->holders)); 2297 2298 dm_sysfs_exit(md); 2299 dm_table_put(map); 2300 dm_table_destroy(__unbind(md)); 2301 free_dev(md); 2302 } 2303 2304 void dm_destroy(struct mapped_device *md) 2305 { 2306 __dm_destroy(md, true); 2307 } 2308 2309 void dm_destroy_immediate(struct mapped_device *md) 2310 { 2311 __dm_destroy(md, false); 2312 } 2313 2314 void dm_put(struct mapped_device *md) 2315 { 2316 atomic_dec(&md->holders); 2317 } 2318 EXPORT_SYMBOL_GPL(dm_put); 2319 2320 static int dm_wait_for_completion(struct mapped_device *md, int interruptible) 2321 { 2322 int r = 0; 2323 DECLARE_WAITQUEUE(wait, current); 2324 2325 add_wait_queue(&md->wait, &wait); 2326 2327 while (1) { 2328 set_current_state(interruptible); 2329 2330 if (!md_in_flight(md)) 2331 break; 2332 2333 if (interruptible == TASK_INTERRUPTIBLE && 2334 signal_pending(current)) { 2335 r = -EINTR; 2336 break; 2337 } 2338 2339 io_schedule(); 2340 } 2341 set_current_state(TASK_RUNNING); 2342 2343 remove_wait_queue(&md->wait, &wait); 2344 2345 return r; 2346 } 2347 2348 /* 2349 * Process the deferred bios 2350 */ 2351 static void dm_wq_work(struct work_struct *work) 2352 { 2353 struct mapped_device *md = container_of(work, struct mapped_device, 2354 work); 2355 struct bio *c; 2356 2357 down_read(&md->io_lock); 2358 2359 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) { 2360 spin_lock_irq(&md->deferred_lock); 2361 c = bio_list_pop(&md->deferred); 2362 spin_unlock_irq(&md->deferred_lock); 2363 2364 if (!c) 2365 break; 2366 2367 up_read(&md->io_lock); 2368 2369 if (dm_request_based(md)) 2370 generic_make_request(c); 2371 else 2372 __split_and_process_bio(md, c); 2373 2374 down_read(&md->io_lock); 2375 } 2376 2377 up_read(&md->io_lock); 2378 } 2379 2380 static void dm_queue_flush(struct mapped_device *md) 2381 { 2382 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); 2383 smp_mb__after_clear_bit(); 2384 queue_work(md->wq, &md->work); 2385 } 2386 2387 /* 2388 * Swap in a new table, returning the old one for the caller to destroy. 2389 */ 2390 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) 2391 { 2392 struct dm_table *live_map, *map = ERR_PTR(-EINVAL); 2393 struct queue_limits limits; 2394 int r; 2395 2396 mutex_lock(&md->suspend_lock); 2397 2398 /* device must be suspended */ 2399 if (!dm_suspended_md(md)) 2400 goto out; 2401 2402 /* 2403 * If the new table has no data devices, retain the existing limits. 2404 * This helps multipath with queue_if_no_path if all paths disappear, 2405 * then new I/O is queued based on these limits, and then some paths 2406 * reappear. 2407 */ 2408 if (dm_table_has_no_data_devices(table)) { 2409 live_map = dm_get_live_table(md); 2410 if (live_map) 2411 limits = md->queue->limits; 2412 dm_table_put(live_map); 2413 } 2414 2415 r = dm_calculate_queue_limits(table, &limits); 2416 if (r) { 2417 map = ERR_PTR(r); 2418 goto out; 2419 } 2420 2421 map = __bind(md, table, &limits); 2422 2423 out: 2424 mutex_unlock(&md->suspend_lock); 2425 return map; 2426 } 2427 2428 /* 2429 * Functions to lock and unlock any filesystem running on the 2430 * device. 2431 */ 2432 static int lock_fs(struct mapped_device *md) 2433 { 2434 int r; 2435 2436 WARN_ON(md->frozen_sb); 2437 2438 md->frozen_sb = freeze_bdev(md->bdev); 2439 if (IS_ERR(md->frozen_sb)) { 2440 r = PTR_ERR(md->frozen_sb); 2441 md->frozen_sb = NULL; 2442 return r; 2443 } 2444 2445 set_bit(DMF_FROZEN, &md->flags); 2446 2447 return 0; 2448 } 2449 2450 static void unlock_fs(struct mapped_device *md) 2451 { 2452 if (!test_bit(DMF_FROZEN, &md->flags)) 2453 return; 2454 2455 thaw_bdev(md->bdev, md->frozen_sb); 2456 md->frozen_sb = NULL; 2457 clear_bit(DMF_FROZEN, &md->flags); 2458 } 2459 2460 /* 2461 * We need to be able to change a mapping table under a mounted 2462 * filesystem. For example we might want to move some data in 2463 * the background. Before the table can be swapped with 2464 * dm_bind_table, dm_suspend must be called to flush any in 2465 * flight bios and ensure that any further io gets deferred. 2466 */ 2467 /* 2468 * Suspend mechanism in request-based dm. 2469 * 2470 * 1. Flush all I/Os by lock_fs() if needed. 2471 * 2. Stop dispatching any I/O by stopping the request_queue. 2472 * 3. Wait for all in-flight I/Os to be completed or requeued. 2473 * 2474 * To abort suspend, start the request_queue. 2475 */ 2476 int dm_suspend(struct mapped_device *md, unsigned suspend_flags) 2477 { 2478 struct dm_table *map = NULL; 2479 int r = 0; 2480 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; 2481 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; 2482 2483 mutex_lock(&md->suspend_lock); 2484 2485 if (dm_suspended_md(md)) { 2486 r = -EINVAL; 2487 goto out_unlock; 2488 } 2489 2490 map = dm_get_live_table(md); 2491 2492 /* 2493 * DMF_NOFLUSH_SUSPENDING must be set before presuspend. 2494 * This flag is cleared before dm_suspend returns. 2495 */ 2496 if (noflush) 2497 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 2498 2499 /* This does not get reverted if there's an error later. */ 2500 dm_table_presuspend_targets(map); 2501 2502 /* 2503 * Flush I/O to the device. 2504 * Any I/O submitted after lock_fs() may not be flushed. 2505 * noflush takes precedence over do_lockfs. 2506 * (lock_fs() flushes I/Os and waits for them to complete.) 2507 */ 2508 if (!noflush && do_lockfs) { 2509 r = lock_fs(md); 2510 if (r) 2511 goto out; 2512 } 2513 2514 /* 2515 * Here we must make sure that no processes are submitting requests 2516 * to target drivers i.e. no one may be executing 2517 * __split_and_process_bio. This is called from dm_request and 2518 * dm_wq_work. 2519 * 2520 * To get all processes out of __split_and_process_bio in dm_request, 2521 * we take the write lock. To prevent any process from reentering 2522 * __split_and_process_bio from dm_request and quiesce the thread 2523 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call 2524 * flush_workqueue(md->wq). 2525 */ 2526 down_write(&md->io_lock); 2527 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); 2528 up_write(&md->io_lock); 2529 2530 /* 2531 * Stop md->queue before flushing md->wq in case request-based 2532 * dm defers requests to md->wq from md->queue. 2533 */ 2534 if (dm_request_based(md)) 2535 stop_queue(md->queue); 2536 2537 flush_workqueue(md->wq); 2538 2539 /* 2540 * At this point no more requests are entering target request routines. 2541 * We call dm_wait_for_completion to wait for all existing requests 2542 * to finish. 2543 */ 2544 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE); 2545 2546 down_write(&md->io_lock); 2547 if (noflush) 2548 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); 2549 up_write(&md->io_lock); 2550 2551 /* were we interrupted ? */ 2552 if (r < 0) { 2553 dm_queue_flush(md); 2554 2555 if (dm_request_based(md)) 2556 start_queue(md->queue); 2557 2558 unlock_fs(md); 2559 goto out; /* pushback list is already flushed, so skip flush */ 2560 } 2561 2562 /* 2563 * If dm_wait_for_completion returned 0, the device is completely 2564 * quiescent now. There is no request-processing activity. All new 2565 * requests are being added to md->deferred list. 2566 */ 2567 2568 set_bit(DMF_SUSPENDED, &md->flags); 2569 2570 dm_table_postsuspend_targets(map); 2571 2572 out: 2573 dm_table_put(map); 2574 2575 out_unlock: 2576 mutex_unlock(&md->suspend_lock); 2577 return r; 2578 } 2579 2580 int dm_resume(struct mapped_device *md) 2581 { 2582 int r = -EINVAL; 2583 struct dm_table *map = NULL; 2584 2585 mutex_lock(&md->suspend_lock); 2586 if (!dm_suspended_md(md)) 2587 goto out; 2588 2589 map = dm_get_live_table(md); 2590 if (!map || !dm_table_get_size(map)) 2591 goto out; 2592 2593 r = dm_table_resume_targets(map); 2594 if (r) 2595 goto out; 2596 2597 dm_queue_flush(md); 2598 2599 /* 2600 * Flushing deferred I/Os must be done after targets are resumed 2601 * so that mapping of targets can work correctly. 2602 * Request-based dm is queueing the deferred I/Os in its request_queue. 2603 */ 2604 if (dm_request_based(md)) 2605 start_queue(md->queue); 2606 2607 unlock_fs(md); 2608 2609 clear_bit(DMF_SUSPENDED, &md->flags); 2610 2611 r = 0; 2612 out: 2613 dm_table_put(map); 2614 mutex_unlock(&md->suspend_lock); 2615 2616 return r; 2617 } 2618 2619 /*----------------------------------------------------------------- 2620 * Event notification. 2621 *---------------------------------------------------------------*/ 2622 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, 2623 unsigned cookie) 2624 { 2625 char udev_cookie[DM_COOKIE_LENGTH]; 2626 char *envp[] = { udev_cookie, NULL }; 2627 2628 if (!cookie) 2629 return kobject_uevent(&disk_to_dev(md->disk)->kobj, action); 2630 else { 2631 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", 2632 DM_COOKIE_ENV_VAR_NAME, cookie); 2633 return kobject_uevent_env(&disk_to_dev(md->disk)->kobj, 2634 action, envp); 2635 } 2636 } 2637 2638 uint32_t dm_next_uevent_seq(struct mapped_device *md) 2639 { 2640 return atomic_add_return(1, &md->uevent_seq); 2641 } 2642 2643 uint32_t dm_get_event_nr(struct mapped_device *md) 2644 { 2645 return atomic_read(&md->event_nr); 2646 } 2647 2648 int dm_wait_event(struct mapped_device *md, int event_nr) 2649 { 2650 return wait_event_interruptible(md->eventq, 2651 (event_nr != atomic_read(&md->event_nr))); 2652 } 2653 2654 void dm_uevent_add(struct mapped_device *md, struct list_head *elist) 2655 { 2656 unsigned long flags; 2657 2658 spin_lock_irqsave(&md->uevent_lock, flags); 2659 list_add(elist, &md->uevent_list); 2660 spin_unlock_irqrestore(&md->uevent_lock, flags); 2661 } 2662 2663 /* 2664 * The gendisk is only valid as long as you have a reference 2665 * count on 'md'. 2666 */ 2667 struct gendisk *dm_disk(struct mapped_device *md) 2668 { 2669 return md->disk; 2670 } 2671 2672 struct kobject *dm_kobject(struct mapped_device *md) 2673 { 2674 return &md->kobj; 2675 } 2676 2677 /* 2678 * struct mapped_device should not be exported outside of dm.c 2679 * so use this check to verify that kobj is part of md structure 2680 */ 2681 struct mapped_device *dm_get_from_kobject(struct kobject *kobj) 2682 { 2683 struct mapped_device *md; 2684 2685 md = container_of(kobj, struct mapped_device, kobj); 2686 if (&md->kobj != kobj) 2687 return NULL; 2688 2689 if (test_bit(DMF_FREEING, &md->flags) || 2690 dm_deleting_md(md)) 2691 return NULL; 2692 2693 dm_get(md); 2694 return md; 2695 } 2696 2697 int dm_suspended_md(struct mapped_device *md) 2698 { 2699 return test_bit(DMF_SUSPENDED, &md->flags); 2700 } 2701 2702 int dm_suspended(struct dm_target *ti) 2703 { 2704 return dm_suspended_md(dm_table_get_md(ti->table)); 2705 } 2706 EXPORT_SYMBOL_GPL(dm_suspended); 2707 2708 int dm_noflush_suspending(struct dm_target *ti) 2709 { 2710 return __noflush_suspending(dm_table_get_md(ti->table)); 2711 } 2712 EXPORT_SYMBOL_GPL(dm_noflush_suspending); 2713 2714 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity) 2715 { 2716 struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL); 2717 unsigned int pool_size = (type == DM_TYPE_BIO_BASED) ? 16 : MIN_IOS; 2718 2719 if (!pools) 2720 return NULL; 2721 2722 pools->io_pool = (type == DM_TYPE_BIO_BASED) ? 2723 mempool_create_slab_pool(MIN_IOS, _io_cache) : 2724 mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache); 2725 if (!pools->io_pool) 2726 goto free_pools_and_out; 2727 2728 pools->tio_pool = NULL; 2729 if (type == DM_TYPE_REQUEST_BASED) { 2730 pools->tio_pool = mempool_create_slab_pool(MIN_IOS, _rq_tio_cache); 2731 if (!pools->tio_pool) 2732 goto free_io_pool_and_out; 2733 } 2734 2735 pools->bs = (type == DM_TYPE_BIO_BASED) ? 2736 bioset_create(pool_size, 2737 offsetof(struct dm_target_io, clone)) : 2738 bioset_create(pool_size, 2739 offsetof(struct dm_rq_clone_bio_info, clone)); 2740 if (!pools->bs) 2741 goto free_tio_pool_and_out; 2742 2743 if (integrity && bioset_integrity_create(pools->bs, pool_size)) 2744 goto free_bioset_and_out; 2745 2746 return pools; 2747 2748 free_bioset_and_out: 2749 bioset_free(pools->bs); 2750 2751 free_tio_pool_and_out: 2752 if (pools->tio_pool) 2753 mempool_destroy(pools->tio_pool); 2754 2755 free_io_pool_and_out: 2756 mempool_destroy(pools->io_pool); 2757 2758 free_pools_and_out: 2759 kfree(pools); 2760 2761 return NULL; 2762 } 2763 2764 void dm_free_md_mempools(struct dm_md_mempools *pools) 2765 { 2766 if (!pools) 2767 return; 2768 2769 if (pools->io_pool) 2770 mempool_destroy(pools->io_pool); 2771 2772 if (pools->tio_pool) 2773 mempool_destroy(pools->tio_pool); 2774 2775 if (pools->bs) 2776 bioset_free(pools->bs); 2777 2778 kfree(pools); 2779 } 2780 2781 static const struct block_device_operations dm_blk_dops = { 2782 .open = dm_blk_open, 2783 .release = dm_blk_close, 2784 .ioctl = dm_blk_ioctl, 2785 .getgeo = dm_blk_getgeo, 2786 .owner = THIS_MODULE 2787 }; 2788 2789 EXPORT_SYMBOL(dm_get_mapinfo); 2790 2791 /* 2792 * module hooks 2793 */ 2794 module_init(dm_init); 2795 module_exit(dm_exit); 2796 2797 module_param(major, uint, 0); 2798 MODULE_PARM_DESC(major, "The major number of the device mapper"); 2799 MODULE_DESCRIPTION(DM_NAME " driver"); 2800 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); 2801 MODULE_LICENSE("GPL"); 2802