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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011-2012 Red Hat UK.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-thin-metadata.h"
9#include "dm-bio-prison-v1.h"
10#include "dm.h"
11
12#include <linux/device-mapper.h>
13#include <linux/dm-io.h>
14#include <linux/dm-kcopyd.h>
15#include <linux/jiffies.h>
16#include <linux/log2.h>
17#include <linux/list.h>
18#include <linux/rculist.h>
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/slab.h>
22#include <linux/vmalloc.h>
23#include <linux/sort.h>
24#include <linux/rbtree.h>
25
26#define DM_MSG_PREFIX "thin"
27
28/*
29 * Tunable constants
30 */
31#define ENDIO_HOOK_POOL_SIZE 1024
32#define MAPPING_POOL_SIZE 1024
33#define COMMIT_PERIOD HZ
34#define NO_SPACE_TIMEOUT_SECS 60
35
36static unsigned int no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
37
38DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
39 "A percentage of time allocated for copy on write");
40
41/*
42 * The block size of the device holding pool data must be
43 * between 64KB and 1GB.
44 */
45#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
46#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
47
48/*
49 * Device id is restricted to 24 bits.
50 */
51#define MAX_DEV_ID ((1 << 24) - 1)
52
53/*
54 * How do we handle breaking sharing of data blocks?
55 * =================================================
56 *
57 * We use a standard copy-on-write btree to store the mappings for the
58 * devices (note I'm talking about copy-on-write of the metadata here, not
59 * the data). When you take an internal snapshot you clone the root node
60 * of the origin btree. After this there is no concept of an origin or a
61 * snapshot. They are just two device trees that happen to point to the
62 * same data blocks.
63 *
64 * When we get a write in we decide if it's to a shared data block using
65 * some timestamp magic. If it is, we have to break sharing.
66 *
67 * Let's say we write to a shared block in what was the origin. The
68 * steps are:
69 *
70 * i) plug io further to this physical block. (see bio_prison code).
71 *
72 * ii) quiesce any read io to that shared data block. Obviously
73 * including all devices that share this block. (see dm_deferred_set code)
74 *
75 * iii) copy the data block to a newly allocate block. This step can be
76 * missed out if the io covers the block. (schedule_copy).
77 *
78 * iv) insert the new mapping into the origin's btree
79 * (process_prepared_mapping). This act of inserting breaks some
80 * sharing of btree nodes between the two devices. Breaking sharing only
81 * effects the btree of that specific device. Btrees for the other
82 * devices that share the block never change. The btree for the origin
83 * device as it was after the last commit is untouched, ie. we're using
84 * persistent data structures in the functional programming sense.
85 *
86 * v) unplug io to this physical block, including the io that triggered
87 * the breaking of sharing.
88 *
89 * Steps (ii) and (iii) occur in parallel.
90 *
91 * The metadata _doesn't_ need to be committed before the io continues. We
92 * get away with this because the io is always written to a _new_ block.
93 * If there's a crash, then:
94 *
95 * - The origin mapping will point to the old origin block (the shared
96 * one). This will contain the data as it was before the io that triggered
97 * the breaking of sharing came in.
98 *
99 * - The snap mapping still points to the old block. As it would after
100 * the commit.
101 *
102 * The downside of this scheme is the timestamp magic isn't perfect, and
103 * will continue to think that data block in the snapshot device is shared
104 * even after the write to the origin has broken sharing. I suspect data
105 * blocks will typically be shared by many different devices, so we're
106 * breaking sharing n + 1 times, rather than n, where n is the number of
107 * devices that reference this data block. At the moment I think the
108 * benefits far, far outweigh the disadvantages.
109 */
110
111/*----------------------------------------------------------------*/
112
113/*
114 * Key building.
115 */
116enum lock_space {
117 VIRTUAL,
118 PHYSICAL
119};
120
121static bool build_key(struct dm_thin_device *td, enum lock_space ls,
122 dm_block_t b, dm_block_t e, struct dm_cell_key *key)
123{
124 key->virtual = (ls == VIRTUAL);
125 key->dev = dm_thin_dev_id(td);
126 key->block_begin = b;
127 key->block_end = e;
128
129 return dm_cell_key_has_valid_range(key);
130}
131
132static void build_data_key(struct dm_thin_device *td, dm_block_t b,
133 struct dm_cell_key *key)
134{
135 (void) build_key(td, PHYSICAL, b, b + 1llu, key);
136}
137
138static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
139 struct dm_cell_key *key)
140{
141 (void) build_key(td, VIRTUAL, b, b + 1llu, key);
142}
143
144/*----------------------------------------------------------------*/
145
146#define THROTTLE_THRESHOLD (1 * HZ)
147
148struct throttle {
149 struct rw_semaphore lock;
150 unsigned long threshold;
151 bool throttle_applied;
152};
153
154static void throttle_init(struct throttle *t)
155{
156 init_rwsem(&t->lock);
157 t->throttle_applied = false;
158}
159
160static void throttle_work_start(struct throttle *t)
161{
162 t->threshold = jiffies + THROTTLE_THRESHOLD;
163}
164
165static void throttle_work_update(struct throttle *t)
166{
167 if (!t->throttle_applied && time_is_before_jiffies(t->threshold)) {
168 down_write(&t->lock);
169 t->throttle_applied = true;
170 }
171}
172
173static void throttle_work_complete(struct throttle *t)
174{
175 if (t->throttle_applied) {
176 t->throttle_applied = false;
177 up_write(&t->lock);
178 }
179}
180
181static void throttle_lock(struct throttle *t)
182{
183 down_read(&t->lock);
184}
185
186static void throttle_unlock(struct throttle *t)
187{
188 up_read(&t->lock);
189}
190
191/*----------------------------------------------------------------*/
192
193/*
194 * A pool device ties together a metadata device and a data device. It
195 * also provides the interface for creating and destroying internal
196 * devices.
197 */
198struct dm_thin_new_mapping;
199
200/*
201 * The pool runs in various modes. Ordered in degraded order for comparisons.
202 */
203enum pool_mode {
204 PM_WRITE, /* metadata may be changed */
205 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
206
207 /*
208 * Like READ_ONLY, except may switch back to WRITE on metadata resize. Reported as READ_ONLY.
209 */
210 PM_OUT_OF_METADATA_SPACE,
211 PM_READ_ONLY, /* metadata may not be changed */
212
213 PM_FAIL, /* all I/O fails */
214};
215
216struct pool_features {
217 enum pool_mode mode;
218
219 bool zero_new_blocks:1;
220 bool discard_enabled:1;
221 bool discard_passdown:1;
222 bool error_if_no_space:1;
223};
224
225struct thin_c;
226typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
227typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
228typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
229
230#define CELL_SORT_ARRAY_SIZE 8192
231
232struct pool {
233 struct list_head list;
234 struct dm_target *ti; /* Only set if a pool target is bound */
235
236 struct mapped_device *pool_md;
237 struct block_device *data_dev;
238 struct block_device *md_dev;
239 struct dm_pool_metadata *pmd;
240
241 dm_block_t low_water_blocks;
242 uint32_t sectors_per_block;
243 int sectors_per_block_shift;
244
245 struct pool_features pf;
246 bool low_water_triggered:1; /* A dm event has been sent */
247 bool suspended:1;
248 bool out_of_data_space:1;
249
250 struct dm_bio_prison *prison;
251 struct dm_kcopyd_client *copier;
252
253 struct work_struct worker;
254 struct workqueue_struct *wq;
255 struct throttle throttle;
256 struct delayed_work waker;
257 struct delayed_work no_space_timeout;
258
259 unsigned long last_commit_jiffies;
260 unsigned int ref_count;
261
262 spinlock_t lock;
263 struct bio_list deferred_flush_bios;
264 struct bio_list deferred_flush_completions;
265 struct list_head prepared_mappings;
266 struct list_head prepared_discards;
267 struct list_head prepared_discards_pt2;
268 struct list_head active_thins;
269
270 struct dm_deferred_set *shared_read_ds;
271 struct dm_deferred_set *all_io_ds;
272
273 struct dm_thin_new_mapping *next_mapping;
274
275 process_bio_fn process_bio;
276 process_bio_fn process_discard;
277
278 process_cell_fn process_cell;
279 process_cell_fn process_discard_cell;
280
281 process_mapping_fn process_prepared_mapping;
282 process_mapping_fn process_prepared_discard;
283 process_mapping_fn process_prepared_discard_pt2;
284
285 struct dm_bio_prison_cell **cell_sort_array;
286
287 mempool_t mapping_pool;
288};
289
290static void metadata_operation_failed(struct pool *pool, const char *op, int r);
291
292static enum pool_mode get_pool_mode(struct pool *pool)
293{
294 return pool->pf.mode;
295}
296
297static void notify_of_pool_mode_change(struct pool *pool)
298{
299 static const char *descs[] = {
300 "write",
301 "out-of-data-space",
302 "read-only",
303 "read-only",
304 "fail"
305 };
306 const char *extra_desc = NULL;
307 enum pool_mode mode = get_pool_mode(pool);
308
309 if (mode == PM_OUT_OF_DATA_SPACE) {
310 if (!pool->pf.error_if_no_space)
311 extra_desc = " (queue IO)";
312 else
313 extra_desc = " (error IO)";
314 }
315
316 dm_table_event(pool->ti->table);
317 DMINFO("%s: switching pool to %s%s mode",
318 dm_device_name(pool->pool_md),
319 descs[(int)mode], extra_desc ? : "");
320}
321
322/*
323 * Target context for a pool.
324 */
325struct pool_c {
326 struct dm_target *ti;
327 struct pool *pool;
328 struct dm_dev *data_dev;
329 struct dm_dev *metadata_dev;
330
331 dm_block_t low_water_blocks;
332 struct pool_features requested_pf; /* Features requested during table load */
333 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
334};
335
336/*
337 * Target context for a thin.
338 */
339struct thin_c {
340 struct list_head list;
341 struct dm_dev *pool_dev;
342 struct dm_dev *origin_dev;
343 sector_t origin_size;
344 dm_thin_id dev_id;
345
346 struct pool *pool;
347 struct dm_thin_device *td;
348 struct mapped_device *thin_md;
349
350 bool requeue_mode:1;
351 spinlock_t lock;
352 struct list_head deferred_cells;
353 struct bio_list deferred_bio_list;
354 struct bio_list retry_on_resume_list;
355 struct rb_root sort_bio_list; /* sorted list of deferred bios */
356
357 /*
358 * Ensures the thin is not destroyed until the worker has finished
359 * iterating the active_thins list.
360 */
361 refcount_t refcount;
362 struct completion can_destroy;
363};
364
365/*----------------------------------------------------------------*/
366
367static bool block_size_is_power_of_two(struct pool *pool)
368{
369 return pool->sectors_per_block_shift >= 0;
370}
371
372static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
373{
374 return block_size_is_power_of_two(pool) ?
375 (b << pool->sectors_per_block_shift) :
376 (b * pool->sectors_per_block);
377}
378
379/*----------------------------------------------------------------*/
380
381struct discard_op {
382 struct thin_c *tc;
383 struct blk_plug plug;
384 struct bio *parent_bio;
385 struct bio *bio;
386};
387
388static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
389{
390 BUG_ON(!parent);
391
392 op->tc = tc;
393 blk_start_plug(&op->plug);
394 op->parent_bio = parent;
395 op->bio = NULL;
396}
397
398static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
399{
400 struct thin_c *tc = op->tc;
401 sector_t s = block_to_sectors(tc->pool, data_b);
402 sector_t len = block_to_sectors(tc->pool, data_e - data_b);
403
404 return __blkdev_issue_discard(tc->pool_dev->bdev, s, len, GFP_NOIO, &op->bio);
405}
406
407static void end_discard(struct discard_op *op, int r)
408{
409 if (op->bio) {
410 /*
411 * Even if one of the calls to issue_discard failed, we
412 * need to wait for the chain to complete.
413 */
414 bio_chain(op->bio, op->parent_bio);
415 op->bio->bi_opf = REQ_OP_DISCARD;
416 submit_bio(op->bio);
417 }
418
419 blk_finish_plug(&op->plug);
420
421 /*
422 * Even if r is set, there could be sub discards in flight that we
423 * need to wait for.
424 */
425 if (r && !op->parent_bio->bi_status)
426 op->parent_bio->bi_status = errno_to_blk_status(r);
427 bio_endio(op->parent_bio);
428}
429
430/*----------------------------------------------------------------*/
431
432/*
433 * wake_worker() is used when new work is queued and when pool_resume is
434 * ready to continue deferred IO processing.
435 */
436static void wake_worker(struct pool *pool)
437{
438 queue_work(pool->wq, &pool->worker);
439}
440
441/*----------------------------------------------------------------*/
442
443static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
444 struct dm_bio_prison_cell **cell_result)
445{
446 int r;
447 struct dm_bio_prison_cell *cell_prealloc;
448
449 /*
450 * Allocate a cell from the prison's mempool.
451 * This might block but it can't fail.
452 */
453 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
454
455 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
456 if (r) {
457 /*
458 * We reused an old cell; we can get rid of
459 * the new one.
460 */
461 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
462 }
463
464 return r;
465}
466
467static void cell_release(struct pool *pool,
468 struct dm_bio_prison_cell *cell,
469 struct bio_list *bios)
470{
471 dm_cell_release(pool->prison, cell, bios);
472 dm_bio_prison_free_cell(pool->prison, cell);
473}
474
475static void cell_visit_release(struct pool *pool,
476 void (*fn)(void *, struct dm_bio_prison_cell *),
477 void *context,
478 struct dm_bio_prison_cell *cell)
479{
480 dm_cell_visit_release(pool->prison, fn, context, cell);
481 dm_bio_prison_free_cell(pool->prison, cell);
482}
483
484static void cell_release_no_holder(struct pool *pool,
485 struct dm_bio_prison_cell *cell,
486 struct bio_list *bios)
487{
488 dm_cell_release_no_holder(pool->prison, cell, bios);
489 dm_bio_prison_free_cell(pool->prison, cell);
490}
491
492static void cell_error_with_code(struct pool *pool,
493 struct dm_bio_prison_cell *cell, blk_status_t error_code)
494{
495 dm_cell_error(pool->prison, cell, error_code);
496 dm_bio_prison_free_cell(pool->prison, cell);
497}
498
499static blk_status_t get_pool_io_error_code(struct pool *pool)
500{
501 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
502}
503
504static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
505{
506 cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
507}
508
509static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
510{
511 cell_error_with_code(pool, cell, 0);
512}
513
514static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
515{
516 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
517}
518
519/*----------------------------------------------------------------*/
520
521/*
522 * A global list of pools that uses a struct mapped_device as a key.
523 */
524static struct dm_thin_pool_table {
525 struct mutex mutex;
526 struct list_head pools;
527} dm_thin_pool_table;
528
529static void pool_table_init(void)
530{
531 mutex_init(&dm_thin_pool_table.mutex);
532 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
533}
534
535static void pool_table_exit(void)
536{
537 mutex_destroy(&dm_thin_pool_table.mutex);
538}
539
540static void __pool_table_insert(struct pool *pool)
541{
542 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
543 list_add(&pool->list, &dm_thin_pool_table.pools);
544}
545
546static void __pool_table_remove(struct pool *pool)
547{
548 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
549 list_del(&pool->list);
550}
551
552static struct pool *__pool_table_lookup(struct mapped_device *md)
553{
554 struct pool *pool = NULL, *tmp;
555
556 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
557
558 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
559 if (tmp->pool_md == md) {
560 pool = tmp;
561 break;
562 }
563 }
564
565 return pool;
566}
567
568static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
569{
570 struct pool *pool = NULL, *tmp;
571
572 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
573
574 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
575 if (tmp->md_dev == md_dev) {
576 pool = tmp;
577 break;
578 }
579 }
580
581 return pool;
582}
583
584/*----------------------------------------------------------------*/
585
586struct dm_thin_endio_hook {
587 struct thin_c *tc;
588 struct dm_deferred_entry *shared_read_entry;
589 struct dm_deferred_entry *all_io_entry;
590 struct dm_thin_new_mapping *overwrite_mapping;
591 struct rb_node rb_node;
592 struct dm_bio_prison_cell *cell;
593};
594
595static void error_bio_list(struct bio_list *bios, blk_status_t error)
596{
597 struct bio *bio;
598
599 while ((bio = bio_list_pop(bios))) {
600 bio->bi_status = error;
601 bio_endio(bio);
602 }
603}
604
605static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
606 blk_status_t error)
607{
608 struct bio_list bios;
609
610 bio_list_init(&bios);
611
612 spin_lock_irq(&tc->lock);
613 bio_list_merge_init(&bios, master);
614 spin_unlock_irq(&tc->lock);
615
616 error_bio_list(&bios, error);
617}
618
619static void requeue_deferred_cells(struct thin_c *tc)
620{
621 struct pool *pool = tc->pool;
622 struct list_head cells;
623 struct dm_bio_prison_cell *cell, *tmp;
624
625 INIT_LIST_HEAD(&cells);
626
627 spin_lock_irq(&tc->lock);
628 list_splice_init(&tc->deferred_cells, &cells);
629 spin_unlock_irq(&tc->lock);
630
631 list_for_each_entry_safe(cell, tmp, &cells, user_list)
632 cell_requeue(pool, cell);
633}
634
635static void requeue_io(struct thin_c *tc)
636{
637 struct bio_list bios;
638
639 bio_list_init(&bios);
640
641 spin_lock_irq(&tc->lock);
642 bio_list_merge_init(&bios, &tc->deferred_bio_list);
643 bio_list_merge_init(&bios, &tc->retry_on_resume_list);
644 spin_unlock_irq(&tc->lock);
645
646 error_bio_list(&bios, BLK_STS_DM_REQUEUE);
647 requeue_deferred_cells(tc);
648}
649
650static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
651{
652 struct thin_c *tc;
653
654 rcu_read_lock();
655 list_for_each_entry_rcu(tc, &pool->active_thins, list)
656 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
657 rcu_read_unlock();
658}
659
660static void error_retry_list(struct pool *pool)
661{
662 error_retry_list_with_code(pool, get_pool_io_error_code(pool));
663}
664
665/*
666 * This section of code contains the logic for processing a thin device's IO.
667 * Much of the code depends on pool object resources (lists, workqueues, etc)
668 * but most is exclusively called from the thin target rather than the thin-pool
669 * target.
670 */
671
672static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
673{
674 struct pool *pool = tc->pool;
675 sector_t block_nr = bio->bi_iter.bi_sector;
676
677 if (block_size_is_power_of_two(pool))
678 block_nr >>= pool->sectors_per_block_shift;
679 else
680 (void) sector_div(block_nr, pool->sectors_per_block);
681
682 return block_nr;
683}
684
685/*
686 * Returns the _complete_ blocks that this bio covers.
687 */
688static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
689 dm_block_t *begin, dm_block_t *end)
690{
691 struct pool *pool = tc->pool;
692 sector_t b = bio->bi_iter.bi_sector;
693 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
694
695 b += pool->sectors_per_block - 1ull; /* so we round up */
696
697 if (block_size_is_power_of_two(pool)) {
698 b >>= pool->sectors_per_block_shift;
699 e >>= pool->sectors_per_block_shift;
700 } else {
701 (void) sector_div(b, pool->sectors_per_block);
702 (void) sector_div(e, pool->sectors_per_block);
703 }
704
705 if (e < b) {
706 /* Can happen if the bio is within a single block. */
707 e = b;
708 }
709
710 *begin = b;
711 *end = e;
712}
713
714static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
715{
716 struct pool *pool = tc->pool;
717 sector_t bi_sector = bio->bi_iter.bi_sector;
718
719 bio_set_dev(bio, tc->pool_dev->bdev);
720 if (block_size_is_power_of_two(pool)) {
721 bio->bi_iter.bi_sector =
722 (block << pool->sectors_per_block_shift) |
723 (bi_sector & (pool->sectors_per_block - 1));
724 } else {
725 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
726 sector_div(bi_sector, pool->sectors_per_block);
727 }
728}
729
730static void remap_to_origin(struct thin_c *tc, struct bio *bio)
731{
732 bio_set_dev(bio, tc->origin_dev->bdev);
733}
734
735static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
736{
737 return op_is_flush(bio->bi_opf) &&
738 dm_thin_changed_this_transaction(tc->td);
739}
740
741static void inc_all_io_entry(struct pool *pool, struct bio *bio)
742{
743 struct dm_thin_endio_hook *h;
744
745 if (bio_op(bio) == REQ_OP_DISCARD)
746 return;
747
748 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
749 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
750}
751
752static void issue(struct thin_c *tc, struct bio *bio)
753{
754 struct pool *pool = tc->pool;
755
756 if (!bio_triggers_commit(tc, bio)) {
757 dm_submit_bio_remap(bio, NULL);
758 return;
759 }
760
761 /*
762 * Complete bio with an error if earlier I/O caused changes to
763 * the metadata that can't be committed e.g, due to I/O errors
764 * on the metadata device.
765 */
766 if (dm_thin_aborted_changes(tc->td)) {
767 bio_io_error(bio);
768 return;
769 }
770
771 /*
772 * Batch together any bios that trigger commits and then issue a
773 * single commit for them in process_deferred_bios().
774 */
775 spin_lock_irq(&pool->lock);
776 bio_list_add(&pool->deferred_flush_bios, bio);
777 spin_unlock_irq(&pool->lock);
778}
779
780static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
781{
782 remap_to_origin(tc, bio);
783 issue(tc, bio);
784}
785
786static void remap_and_issue(struct thin_c *tc, struct bio *bio,
787 dm_block_t block)
788{
789 remap(tc, bio, block);
790 issue(tc, bio);
791}
792
793/*----------------------------------------------------------------*/
794
795/*
796 * Bio endio functions.
797 */
798struct dm_thin_new_mapping {
799 struct list_head list;
800
801 bool pass_discard:1;
802 bool maybe_shared:1;
803
804 /*
805 * Track quiescing, copying and zeroing preparation actions. When this
806 * counter hits zero the block is prepared and can be inserted into the
807 * btree.
808 */
809 atomic_t prepare_actions;
810
811 blk_status_t status;
812 struct thin_c *tc;
813 dm_block_t virt_begin, virt_end;
814 dm_block_t data_block;
815 struct dm_bio_prison_cell *cell;
816
817 /*
818 * If the bio covers the whole area of a block then we can avoid
819 * zeroing or copying. Instead this bio is hooked. The bio will
820 * still be in the cell, so care has to be taken to avoid issuing
821 * the bio twice.
822 */
823 struct bio *bio;
824 bio_end_io_t *saved_bi_end_io;
825};
826
827static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
828{
829 struct pool *pool = m->tc->pool;
830
831 if (atomic_dec_and_test(&m->prepare_actions)) {
832 list_add_tail(&m->list, &pool->prepared_mappings);
833 wake_worker(pool);
834 }
835}
836
837static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
838{
839 unsigned long flags;
840 struct pool *pool = m->tc->pool;
841
842 spin_lock_irqsave(&pool->lock, flags);
843 __complete_mapping_preparation(m);
844 spin_unlock_irqrestore(&pool->lock, flags);
845}
846
847static void copy_complete(int read_err, unsigned long write_err, void *context)
848{
849 struct dm_thin_new_mapping *m = context;
850
851 m->status = read_err || write_err ? BLK_STS_IOERR : 0;
852 complete_mapping_preparation(m);
853}
854
855static void overwrite_endio(struct bio *bio)
856{
857 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
858 struct dm_thin_new_mapping *m = h->overwrite_mapping;
859
860 bio->bi_end_io = m->saved_bi_end_io;
861
862 m->status = bio->bi_status;
863 complete_mapping_preparation(m);
864}
865
866/*----------------------------------------------------------------*/
867
868/*
869 * Workqueue.
870 */
871
872/*
873 * Prepared mapping jobs.
874 */
875
876/*
877 * This sends the bios in the cell, except the original holder, back
878 * to the deferred_bios list.
879 */
880static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
881{
882 struct pool *pool = tc->pool;
883 unsigned long flags;
884 struct bio_list bios;
885
886 bio_list_init(&bios);
887 cell_release_no_holder(pool, cell, &bios);
888
889 if (!bio_list_empty(&bios)) {
890 spin_lock_irqsave(&tc->lock, flags);
891 bio_list_merge(&tc->deferred_bio_list, &bios);
892 spin_unlock_irqrestore(&tc->lock, flags);
893 wake_worker(pool);
894 }
895}
896
897static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
898
899struct remap_info {
900 struct thin_c *tc;
901 struct bio_list defer_bios;
902 struct bio_list issue_bios;
903};
904
905static void __inc_remap_and_issue_cell(void *context,
906 struct dm_bio_prison_cell *cell)
907{
908 struct remap_info *info = context;
909 struct bio *bio;
910
911 while ((bio = bio_list_pop(&cell->bios))) {
912 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
913 bio_list_add(&info->defer_bios, bio);
914 else {
915 inc_all_io_entry(info->tc->pool, bio);
916
917 /*
918 * We can't issue the bios with the bio prison lock
919 * held, so we add them to a list to issue on
920 * return from this function.
921 */
922 bio_list_add(&info->issue_bios, bio);
923 }
924 }
925}
926
927static void inc_remap_and_issue_cell(struct thin_c *tc,
928 struct dm_bio_prison_cell *cell,
929 dm_block_t block)
930{
931 struct bio *bio;
932 struct remap_info info;
933
934 info.tc = tc;
935 bio_list_init(&info.defer_bios);
936 bio_list_init(&info.issue_bios);
937
938 /*
939 * We have to be careful to inc any bios we're about to issue
940 * before the cell is released, and avoid a race with new bios
941 * being added to the cell.
942 */
943 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
944 &info, cell);
945
946 while ((bio = bio_list_pop(&info.defer_bios)))
947 thin_defer_bio(tc, bio);
948
949 while ((bio = bio_list_pop(&info.issue_bios)))
950 remap_and_issue(info.tc, bio, block);
951}
952
953static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
954{
955 cell_error(m->tc->pool, m->cell);
956 list_del(&m->list);
957 mempool_free(m, &m->tc->pool->mapping_pool);
958}
959
960static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio)
961{
962 struct pool *pool = tc->pool;
963
964 /*
965 * If the bio has the REQ_FUA flag set we must commit the metadata
966 * before signaling its completion.
967 */
968 if (!bio_triggers_commit(tc, bio)) {
969 bio_endio(bio);
970 return;
971 }
972
973 /*
974 * Complete bio with an error if earlier I/O caused changes to the
975 * metadata that can't be committed, e.g, due to I/O errors on the
976 * metadata device.
977 */
978 if (dm_thin_aborted_changes(tc->td)) {
979 bio_io_error(bio);
980 return;
981 }
982
983 /*
984 * Batch together any bios that trigger commits and then issue a
985 * single commit for them in process_deferred_bios().
986 */
987 spin_lock_irq(&pool->lock);
988 bio_list_add(&pool->deferred_flush_completions, bio);
989 spin_unlock_irq(&pool->lock);
990}
991
992static void process_prepared_mapping(struct dm_thin_new_mapping *m)
993{
994 struct thin_c *tc = m->tc;
995 struct pool *pool = tc->pool;
996 struct bio *bio = m->bio;
997 int r;
998
999 if (m->status) {
1000 cell_error(pool, m->cell);
1001 goto out;
1002 }
1003
1004 /*
1005 * Commit the prepared block into the mapping btree.
1006 * Any I/O for this block arriving after this point will get
1007 * remapped to it directly.
1008 */
1009 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
1010 if (r) {
1011 metadata_operation_failed(pool, "dm_thin_insert_block", r);
1012 cell_error(pool, m->cell);
1013 goto out;
1014 }
1015
1016 /*
1017 * Release any bios held while the block was being provisioned.
1018 * If we are processing a write bio that completely covers the block,
1019 * we already processed it so can ignore it now when processing
1020 * the bios in the cell.
1021 */
1022 if (bio) {
1023 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1024 complete_overwrite_bio(tc, bio);
1025 } else {
1026 inc_all_io_entry(tc->pool, m->cell->holder);
1027 remap_and_issue(tc, m->cell->holder, m->data_block);
1028 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1029 }
1030
1031out:
1032 list_del(&m->list);
1033 mempool_free(m, &pool->mapping_pool);
1034}
1035
1036/*----------------------------------------------------------------*/
1037
1038static void free_discard_mapping(struct dm_thin_new_mapping *m)
1039{
1040 struct thin_c *tc = m->tc;
1041
1042 if (m->cell)
1043 cell_defer_no_holder(tc, m->cell);
1044 mempool_free(m, &tc->pool->mapping_pool);
1045}
1046
1047static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
1048{
1049 bio_io_error(m->bio);
1050 free_discard_mapping(m);
1051}
1052
1053static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
1054{
1055 bio_endio(m->bio);
1056 free_discard_mapping(m);
1057}
1058
1059static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
1060{
1061 int r;
1062 struct thin_c *tc = m->tc;
1063
1064 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
1065 if (r) {
1066 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
1067 bio_io_error(m->bio);
1068 } else
1069 bio_endio(m->bio);
1070
1071 cell_defer_no_holder(tc, m->cell);
1072 mempool_free(m, &tc->pool->mapping_pool);
1073}
1074
1075/*----------------------------------------------------------------*/
1076
1077static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
1078 struct bio *discard_parent)
1079{
1080 /*
1081 * We've already unmapped this range of blocks, but before we
1082 * passdown we have to check that these blocks are now unused.
1083 */
1084 int r = 0;
1085 bool shared = true;
1086 struct thin_c *tc = m->tc;
1087 struct pool *pool = tc->pool;
1088 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
1089 struct discard_op op;
1090
1091 begin_discard(&op, tc, discard_parent);
1092 while (b != end) {
1093 /* find start of unmapped run */
1094 for (; b < end; b++) {
1095 r = dm_pool_block_is_shared(pool->pmd, b, &shared);
1096 if (r)
1097 goto out;
1098
1099 if (!shared)
1100 break;
1101 }
1102
1103 if (b == end)
1104 break;
1105
1106 /* find end of run */
1107 for (e = b + 1; e != end; e++) {
1108 r = dm_pool_block_is_shared(pool->pmd, e, &shared);
1109 if (r)
1110 goto out;
1111
1112 if (shared)
1113 break;
1114 }
1115
1116 r = issue_discard(&op, b, e);
1117 if (r)
1118 goto out;
1119
1120 b = e;
1121 }
1122out:
1123 end_discard(&op, r);
1124}
1125
1126static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
1127{
1128 unsigned long flags;
1129 struct pool *pool = m->tc->pool;
1130
1131 spin_lock_irqsave(&pool->lock, flags);
1132 list_add_tail(&m->list, &pool->prepared_discards_pt2);
1133 spin_unlock_irqrestore(&pool->lock, flags);
1134 wake_worker(pool);
1135}
1136
1137static void passdown_endio(struct bio *bio)
1138{
1139 /*
1140 * It doesn't matter if the passdown discard failed, we still want
1141 * to unmap (we ignore err).
1142 */
1143 queue_passdown_pt2(bio->bi_private);
1144 bio_put(bio);
1145}
1146
1147static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
1148{
1149 int r;
1150 struct thin_c *tc = m->tc;
1151 struct pool *pool = tc->pool;
1152 struct bio *discard_parent;
1153 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
1154
1155 /*
1156 * Only this thread allocates blocks, so we can be sure that the
1157 * newly unmapped blocks will not be allocated before the end of
1158 * the function.
1159 */
1160 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
1161 if (r) {
1162 metadata_operation_failed(pool, "dm_thin_remove_range", r);
1163 bio_io_error(m->bio);
1164 cell_defer_no_holder(tc, m->cell);
1165 mempool_free(m, &pool->mapping_pool);
1166 return;
1167 }
1168
1169 /*
1170 * Increment the unmapped blocks. This prevents a race between the
1171 * passdown io and reallocation of freed blocks.
1172 */
1173 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
1174 if (r) {
1175 metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
1176 bio_io_error(m->bio);
1177 cell_defer_no_holder(tc, m->cell);
1178 mempool_free(m, &pool->mapping_pool);
1179 return;
1180 }
1181
1182 discard_parent = bio_alloc(NULL, 1, 0, GFP_NOIO);
1183 discard_parent->bi_end_io = passdown_endio;
1184 discard_parent->bi_private = m;
1185 if (m->maybe_shared)
1186 passdown_double_checking_shared_status(m, discard_parent);
1187 else {
1188 struct discard_op op;
1189
1190 begin_discard(&op, tc, discard_parent);
1191 r = issue_discard(&op, m->data_block, data_end);
1192 end_discard(&op, r);
1193 }
1194}
1195
1196static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1197{
1198 int r;
1199 struct thin_c *tc = m->tc;
1200 struct pool *pool = tc->pool;
1201
1202 /*
1203 * The passdown has completed, so now we can decrement all those
1204 * unmapped blocks.
1205 */
1206 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1207 m->data_block + (m->virt_end - m->virt_begin));
1208 if (r) {
1209 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1210 bio_io_error(m->bio);
1211 } else
1212 bio_endio(m->bio);
1213
1214 cell_defer_no_holder(tc, m->cell);
1215 mempool_free(m, &pool->mapping_pool);
1216}
1217
1218static void process_prepared(struct pool *pool, struct list_head *head,
1219 process_mapping_fn *fn)
1220{
1221 struct list_head maps;
1222 struct dm_thin_new_mapping *m, *tmp;
1223
1224 INIT_LIST_HEAD(&maps);
1225 spin_lock_irq(&pool->lock);
1226 list_splice_init(head, &maps);
1227 spin_unlock_irq(&pool->lock);
1228
1229 list_for_each_entry_safe(m, tmp, &maps, list)
1230 (*fn)(m);
1231}
1232
1233/*
1234 * Deferred bio jobs.
1235 */
1236static int io_overlaps_block(struct pool *pool, struct bio *bio)
1237{
1238 return bio->bi_iter.bi_size ==
1239 (pool->sectors_per_block << SECTOR_SHIFT);
1240}
1241
1242static int io_overwrites_block(struct pool *pool, struct bio *bio)
1243{
1244 return (bio_data_dir(bio) == WRITE) &&
1245 io_overlaps_block(pool, bio);
1246}
1247
1248static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1249 bio_end_io_t *fn)
1250{
1251 *save = bio->bi_end_io;
1252 bio->bi_end_io = fn;
1253}
1254
1255static int ensure_next_mapping(struct pool *pool)
1256{
1257 if (pool->next_mapping)
1258 return 0;
1259
1260 pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC);
1261
1262 return pool->next_mapping ? 0 : -ENOMEM;
1263}
1264
1265static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1266{
1267 struct dm_thin_new_mapping *m = pool->next_mapping;
1268
1269 BUG_ON(!pool->next_mapping);
1270
1271 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1272 INIT_LIST_HEAD(&m->list);
1273 m->bio = NULL;
1274
1275 pool->next_mapping = NULL;
1276
1277 return m;
1278}
1279
1280static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1281 sector_t begin, sector_t end)
1282{
1283 struct dm_io_region to;
1284
1285 to.bdev = tc->pool_dev->bdev;
1286 to.sector = begin;
1287 to.count = end - begin;
1288
1289 dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1290}
1291
1292static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1293 dm_block_t data_begin,
1294 struct dm_thin_new_mapping *m)
1295{
1296 struct pool *pool = tc->pool;
1297 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1298
1299 h->overwrite_mapping = m;
1300 m->bio = bio;
1301 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1302 inc_all_io_entry(pool, bio);
1303 remap_and_issue(tc, bio, data_begin);
1304}
1305
1306/*
1307 * A partial copy also needs to zero the uncopied region.
1308 */
1309static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1310 struct dm_dev *origin, dm_block_t data_origin,
1311 dm_block_t data_dest,
1312 struct dm_bio_prison_cell *cell, struct bio *bio,
1313 sector_t len)
1314{
1315 struct pool *pool = tc->pool;
1316 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1317
1318 m->tc = tc;
1319 m->virt_begin = virt_block;
1320 m->virt_end = virt_block + 1u;
1321 m->data_block = data_dest;
1322 m->cell = cell;
1323
1324 /*
1325 * quiesce action + copy action + an extra reference held for the
1326 * duration of this function (we may need to inc later for a
1327 * partial zero).
1328 */
1329 atomic_set(&m->prepare_actions, 3);
1330
1331 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1332 complete_mapping_preparation(m); /* already quiesced */
1333
1334 /*
1335 * IO to pool_dev remaps to the pool target's data_dev.
1336 *
1337 * If the whole block of data is being overwritten, we can issue the
1338 * bio immediately. Otherwise we use kcopyd to clone the data first.
1339 */
1340 if (io_overwrites_block(pool, bio))
1341 remap_and_issue_overwrite(tc, bio, data_dest, m);
1342 else {
1343 struct dm_io_region from, to;
1344
1345 from.bdev = origin->bdev;
1346 from.sector = data_origin * pool->sectors_per_block;
1347 from.count = len;
1348
1349 to.bdev = tc->pool_dev->bdev;
1350 to.sector = data_dest * pool->sectors_per_block;
1351 to.count = len;
1352
1353 dm_kcopyd_copy(pool->copier, &from, 1, &to,
1354 0, copy_complete, m);
1355
1356 /*
1357 * Do we need to zero a tail region?
1358 */
1359 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1360 atomic_inc(&m->prepare_actions);
1361 ll_zero(tc, m,
1362 data_dest * pool->sectors_per_block + len,
1363 (data_dest + 1) * pool->sectors_per_block);
1364 }
1365 }
1366
1367 complete_mapping_preparation(m); /* drop our ref */
1368}
1369
1370static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1371 dm_block_t data_origin, dm_block_t data_dest,
1372 struct dm_bio_prison_cell *cell, struct bio *bio)
1373{
1374 schedule_copy(tc, virt_block, tc->pool_dev,
1375 data_origin, data_dest, cell, bio,
1376 tc->pool->sectors_per_block);
1377}
1378
1379static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1380 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1381 struct bio *bio)
1382{
1383 struct pool *pool = tc->pool;
1384 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1385
1386 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1387 m->tc = tc;
1388 m->virt_begin = virt_block;
1389 m->virt_end = virt_block + 1u;
1390 m->data_block = data_block;
1391 m->cell = cell;
1392
1393 /*
1394 * If the whole block of data is being overwritten or we are not
1395 * zeroing pre-existing data, we can issue the bio immediately.
1396 * Otherwise we use kcopyd to zero the data first.
1397 */
1398 if (pool->pf.zero_new_blocks) {
1399 if (io_overwrites_block(pool, bio))
1400 remap_and_issue_overwrite(tc, bio, data_block, m);
1401 else {
1402 ll_zero(tc, m, data_block * pool->sectors_per_block,
1403 (data_block + 1) * pool->sectors_per_block);
1404 }
1405 } else
1406 process_prepared_mapping(m);
1407}
1408
1409static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1410 dm_block_t data_dest,
1411 struct dm_bio_prison_cell *cell, struct bio *bio)
1412{
1413 struct pool *pool = tc->pool;
1414 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1415 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1416
1417 if (virt_block_end <= tc->origin_size) {
1418 schedule_copy(tc, virt_block, tc->origin_dev,
1419 virt_block, data_dest, cell, bio,
1420 pool->sectors_per_block);
1421
1422 } else if (virt_block_begin < tc->origin_size) {
1423 schedule_copy(tc, virt_block, tc->origin_dev,
1424 virt_block, data_dest, cell, bio,
1425 tc->origin_size - virt_block_begin);
1426
1427 } else
1428 schedule_zero(tc, virt_block, data_dest, cell, bio);
1429}
1430
1431static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1432
1433static void requeue_bios(struct pool *pool);
1434
1435static bool is_read_only_pool_mode(enum pool_mode mode)
1436{
1437 return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY);
1438}
1439
1440static bool is_read_only(struct pool *pool)
1441{
1442 return is_read_only_pool_mode(get_pool_mode(pool));
1443}
1444
1445static void check_for_metadata_space(struct pool *pool)
1446{
1447 int r;
1448 const char *ooms_reason = NULL;
1449 dm_block_t nr_free;
1450
1451 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free);
1452 if (r)
1453 ooms_reason = "Could not get free metadata blocks";
1454 else if (!nr_free)
1455 ooms_reason = "No free metadata blocks";
1456
1457 if (ooms_reason && !is_read_only(pool)) {
1458 DMERR("%s", ooms_reason);
1459 set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE);
1460 }
1461}
1462
1463static void check_for_data_space(struct pool *pool)
1464{
1465 int r;
1466 dm_block_t nr_free;
1467
1468 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1469 return;
1470
1471 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1472 if (r)
1473 return;
1474
1475 if (nr_free) {
1476 set_pool_mode(pool, PM_WRITE);
1477 requeue_bios(pool);
1478 }
1479}
1480
1481/*
1482 * A non-zero return indicates read_only or fail_io mode.
1483 * Many callers don't care about the return value.
1484 */
1485static int commit(struct pool *pool)
1486{
1487 int r;
1488
1489 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE)
1490 return -EINVAL;
1491
1492 r = dm_pool_commit_metadata(pool->pmd);
1493 if (r)
1494 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1495 else {
1496 check_for_metadata_space(pool);
1497 check_for_data_space(pool);
1498 }
1499
1500 return r;
1501}
1502
1503static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1504{
1505 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1506 DMWARN("%s: reached low water mark for data device: sending event.",
1507 dm_device_name(pool->pool_md));
1508 spin_lock_irq(&pool->lock);
1509 pool->low_water_triggered = true;
1510 spin_unlock_irq(&pool->lock);
1511 dm_table_event(pool->ti->table);
1512 }
1513}
1514
1515static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1516{
1517 int r;
1518 dm_block_t free_blocks;
1519 struct pool *pool = tc->pool;
1520
1521 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1522 return -EINVAL;
1523
1524 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1525 if (r) {
1526 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1527 return r;
1528 }
1529
1530 check_low_water_mark(pool, free_blocks);
1531
1532 if (!free_blocks) {
1533 /*
1534 * Try to commit to see if that will free up some
1535 * more space.
1536 */
1537 r = commit(pool);
1538 if (r)
1539 return r;
1540
1541 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1542 if (r) {
1543 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1544 return r;
1545 }
1546
1547 if (!free_blocks) {
1548 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1549 return -ENOSPC;
1550 }
1551 }
1552
1553 r = dm_pool_alloc_data_block(pool->pmd, result);
1554 if (r) {
1555 if (r == -ENOSPC)
1556 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1557 else
1558 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1559 return r;
1560 }
1561
1562 r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks);
1563 if (r) {
1564 metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r);
1565 return r;
1566 }
1567
1568 if (!free_blocks) {
1569 /* Let's commit before we use up the metadata reserve. */
1570 r = commit(pool);
1571 if (r)
1572 return r;
1573 }
1574
1575 return 0;
1576}
1577
1578/*
1579 * If we have run out of space, queue bios until the device is
1580 * resumed, presumably after having been reloaded with more space.
1581 */
1582static void retry_on_resume(struct bio *bio)
1583{
1584 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1585 struct thin_c *tc = h->tc;
1586
1587 spin_lock_irq(&tc->lock);
1588 bio_list_add(&tc->retry_on_resume_list, bio);
1589 spin_unlock_irq(&tc->lock);
1590}
1591
1592static blk_status_t should_error_unserviceable_bio(struct pool *pool)
1593{
1594 enum pool_mode m = get_pool_mode(pool);
1595
1596 switch (m) {
1597 case PM_WRITE:
1598 /* Shouldn't get here */
1599 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1600 return BLK_STS_IOERR;
1601
1602 case PM_OUT_OF_DATA_SPACE:
1603 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
1604
1605 case PM_OUT_OF_METADATA_SPACE:
1606 case PM_READ_ONLY:
1607 case PM_FAIL:
1608 return BLK_STS_IOERR;
1609 default:
1610 /* Shouldn't get here */
1611 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1612 return BLK_STS_IOERR;
1613 }
1614}
1615
1616static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1617{
1618 blk_status_t error = should_error_unserviceable_bio(pool);
1619
1620 if (error) {
1621 bio->bi_status = error;
1622 bio_endio(bio);
1623 } else
1624 retry_on_resume(bio);
1625}
1626
1627static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1628{
1629 struct bio *bio;
1630 struct bio_list bios;
1631 blk_status_t error;
1632
1633 error = should_error_unserviceable_bio(pool);
1634 if (error) {
1635 cell_error_with_code(pool, cell, error);
1636 return;
1637 }
1638
1639 bio_list_init(&bios);
1640 cell_release(pool, cell, &bios);
1641
1642 while ((bio = bio_list_pop(&bios)))
1643 retry_on_resume(bio);
1644}
1645
1646static void process_discard_cell_no_passdown(struct thin_c *tc,
1647 struct dm_bio_prison_cell *virt_cell)
1648{
1649 struct pool *pool = tc->pool;
1650 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1651
1652 /*
1653 * We don't need to lock the data blocks, since there's no
1654 * passdown. We only lock data blocks for allocation and breaking sharing.
1655 */
1656 m->tc = tc;
1657 m->virt_begin = virt_cell->key.block_begin;
1658 m->virt_end = virt_cell->key.block_end;
1659 m->cell = virt_cell;
1660 m->bio = virt_cell->holder;
1661
1662 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1663 pool->process_prepared_discard(m);
1664}
1665
1666static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1667 struct bio *bio)
1668{
1669 struct pool *pool = tc->pool;
1670
1671 int r;
1672 bool maybe_shared;
1673 struct dm_cell_key data_key;
1674 struct dm_bio_prison_cell *data_cell;
1675 struct dm_thin_new_mapping *m;
1676 dm_block_t virt_begin, virt_end, data_begin, data_end;
1677 dm_block_t len, next_boundary;
1678
1679 while (begin != end) {
1680 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1681 &data_begin, &maybe_shared);
1682 if (r) {
1683 /*
1684 * Silently fail, letting any mappings we've
1685 * created complete.
1686 */
1687 break;
1688 }
1689
1690 data_end = data_begin + (virt_end - virt_begin);
1691
1692 /*
1693 * Make sure the data region obeys the bio prison restrictions.
1694 */
1695 while (data_begin < data_end) {
1696 r = ensure_next_mapping(pool);
1697 if (r)
1698 return; /* we did our best */
1699
1700 next_boundary = ((data_begin >> BIO_PRISON_MAX_RANGE_SHIFT) + 1)
1701 << BIO_PRISON_MAX_RANGE_SHIFT;
1702 len = min_t(sector_t, data_end - data_begin, next_boundary - data_begin);
1703
1704 /* This key is certainly within range given the above splitting */
1705 (void) build_key(tc->td, PHYSICAL, data_begin, data_begin + len, &data_key);
1706 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1707 /* contention, we'll give up with this range */
1708 data_begin += len;
1709 continue;
1710 }
1711
1712 /*
1713 * IO may still be going to the destination block. We must
1714 * quiesce before we can do the removal.
1715 */
1716 m = get_next_mapping(pool);
1717 m->tc = tc;
1718 m->maybe_shared = maybe_shared;
1719 m->virt_begin = virt_begin;
1720 m->virt_end = virt_begin + len;
1721 m->data_block = data_begin;
1722 m->cell = data_cell;
1723 m->bio = bio;
1724
1725 /*
1726 * The parent bio must not complete before sub discard bios are
1727 * chained to it (see end_discard's bio_chain)!
1728 *
1729 * This per-mapping bi_remaining increment is paired with
1730 * the implicit decrement that occurs via bio_endio() in
1731 * end_discard().
1732 */
1733 bio_inc_remaining(bio);
1734 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1735 pool->process_prepared_discard(m);
1736
1737 virt_begin += len;
1738 data_begin += len;
1739 }
1740
1741 begin = virt_end;
1742 }
1743}
1744
1745static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1746{
1747 struct bio *bio = virt_cell->holder;
1748 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1749
1750 /*
1751 * The virt_cell will only get freed once the origin bio completes.
1752 * This means it will remain locked while all the individual
1753 * passdown bios are in flight.
1754 */
1755 h->cell = virt_cell;
1756 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1757
1758 /*
1759 * We complete the bio now, knowing that the bi_remaining field
1760 * will prevent completion until the sub range discards have
1761 * completed.
1762 */
1763 bio_endio(bio);
1764}
1765
1766static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1767{
1768 dm_block_t begin, end;
1769 struct dm_cell_key virt_key;
1770 struct dm_bio_prison_cell *virt_cell;
1771
1772 get_bio_block_range(tc, bio, &begin, &end);
1773 if (begin == end) {
1774 /*
1775 * The discard covers less than a block.
1776 */
1777 bio_endio(bio);
1778 return;
1779 }
1780
1781 if (unlikely(!build_key(tc->td, VIRTUAL, begin, end, &virt_key))) {
1782 DMERR_LIMIT("Discard doesn't respect bio prison limits");
1783 bio_endio(bio);
1784 return;
1785 }
1786
1787 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) {
1788 /*
1789 * Potential starvation issue: We're relying on the
1790 * fs/application being well behaved, and not trying to
1791 * send IO to a region at the same time as discarding it.
1792 * If they do this persistently then it's possible this
1793 * cell will never be granted.
1794 */
1795 return;
1796 }
1797
1798 tc->pool->process_discard_cell(tc, virt_cell);
1799}
1800
1801static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1802 struct dm_cell_key *key,
1803 struct dm_thin_lookup_result *lookup_result,
1804 struct dm_bio_prison_cell *cell)
1805{
1806 int r;
1807 dm_block_t data_block;
1808 struct pool *pool = tc->pool;
1809
1810 r = alloc_data_block(tc, &data_block);
1811 switch (r) {
1812 case 0:
1813 schedule_internal_copy(tc, block, lookup_result->block,
1814 data_block, cell, bio);
1815 break;
1816
1817 case -ENOSPC:
1818 retry_bios_on_resume(pool, cell);
1819 break;
1820
1821 default:
1822 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1823 __func__, r);
1824 cell_error(pool, cell);
1825 break;
1826 }
1827}
1828
1829static void __remap_and_issue_shared_cell(void *context,
1830 struct dm_bio_prison_cell *cell)
1831{
1832 struct remap_info *info = context;
1833 struct bio *bio;
1834
1835 while ((bio = bio_list_pop(&cell->bios))) {
1836 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
1837 bio_op(bio) == REQ_OP_DISCARD)
1838 bio_list_add(&info->defer_bios, bio);
1839 else {
1840 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1841
1842 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1843 inc_all_io_entry(info->tc->pool, bio);
1844 bio_list_add(&info->issue_bios, bio);
1845 }
1846 }
1847}
1848
1849static void remap_and_issue_shared_cell(struct thin_c *tc,
1850 struct dm_bio_prison_cell *cell,
1851 dm_block_t block)
1852{
1853 struct bio *bio;
1854 struct remap_info info;
1855
1856 info.tc = tc;
1857 bio_list_init(&info.defer_bios);
1858 bio_list_init(&info.issue_bios);
1859
1860 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1861 &info, cell);
1862
1863 while ((bio = bio_list_pop(&info.defer_bios)))
1864 thin_defer_bio(tc, bio);
1865
1866 while ((bio = bio_list_pop(&info.issue_bios)))
1867 remap_and_issue(tc, bio, block);
1868}
1869
1870static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1871 dm_block_t block,
1872 struct dm_thin_lookup_result *lookup_result,
1873 struct dm_bio_prison_cell *virt_cell)
1874{
1875 struct dm_bio_prison_cell *data_cell;
1876 struct pool *pool = tc->pool;
1877 struct dm_cell_key key;
1878
1879 /*
1880 * If cell is already occupied, then sharing is already in the process
1881 * of being broken so we have nothing further to do here.
1882 */
1883 build_data_key(tc->td, lookup_result->block, &key);
1884 if (bio_detain(pool, &key, bio, &data_cell)) {
1885 cell_defer_no_holder(tc, virt_cell);
1886 return;
1887 }
1888
1889 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1890 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1891 cell_defer_no_holder(tc, virt_cell);
1892 } else {
1893 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1894
1895 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1896 inc_all_io_entry(pool, bio);
1897 remap_and_issue(tc, bio, lookup_result->block);
1898
1899 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1900 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1901 }
1902}
1903
1904static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1905 struct dm_bio_prison_cell *cell)
1906{
1907 int r;
1908 dm_block_t data_block;
1909 struct pool *pool = tc->pool;
1910
1911 /*
1912 * Remap empty bios (flushes) immediately, without provisioning.
1913 */
1914 if (!bio->bi_iter.bi_size) {
1915 inc_all_io_entry(pool, bio);
1916 cell_defer_no_holder(tc, cell);
1917
1918 remap_and_issue(tc, bio, 0);
1919 return;
1920 }
1921
1922 /*
1923 * Fill read bios with zeroes and complete them immediately.
1924 */
1925 if (bio_data_dir(bio) == READ) {
1926 zero_fill_bio(bio);
1927 cell_defer_no_holder(tc, cell);
1928 bio_endio(bio);
1929 return;
1930 }
1931
1932 r = alloc_data_block(tc, &data_block);
1933 switch (r) {
1934 case 0:
1935 if (tc->origin_dev)
1936 schedule_external_copy(tc, block, data_block, cell, bio);
1937 else
1938 schedule_zero(tc, block, data_block, cell, bio);
1939 break;
1940
1941 case -ENOSPC:
1942 retry_bios_on_resume(pool, cell);
1943 break;
1944
1945 default:
1946 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1947 __func__, r);
1948 cell_error(pool, cell);
1949 break;
1950 }
1951}
1952
1953static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1954{
1955 int r;
1956 struct pool *pool = tc->pool;
1957 struct bio *bio = cell->holder;
1958 dm_block_t block = get_bio_block(tc, bio);
1959 struct dm_thin_lookup_result lookup_result;
1960
1961 if (tc->requeue_mode) {
1962 cell_requeue(pool, cell);
1963 return;
1964 }
1965
1966 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1967 switch (r) {
1968 case 0:
1969 if (lookup_result.shared)
1970 process_shared_bio(tc, bio, block, &lookup_result, cell);
1971 else {
1972 inc_all_io_entry(pool, bio);
1973 remap_and_issue(tc, bio, lookup_result.block);
1974 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1975 }
1976 break;
1977
1978 case -ENODATA:
1979 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1980 inc_all_io_entry(pool, bio);
1981 cell_defer_no_holder(tc, cell);
1982
1983 if (bio_end_sector(bio) <= tc->origin_size)
1984 remap_to_origin_and_issue(tc, bio);
1985
1986 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1987 zero_fill_bio(bio);
1988 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1989 remap_to_origin_and_issue(tc, bio);
1990
1991 } else {
1992 zero_fill_bio(bio);
1993 bio_endio(bio);
1994 }
1995 } else
1996 provision_block(tc, bio, block, cell);
1997 break;
1998
1999 default:
2000 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2001 __func__, r);
2002 cell_defer_no_holder(tc, cell);
2003 bio_io_error(bio);
2004 break;
2005 }
2006}
2007
2008static void process_bio(struct thin_c *tc, struct bio *bio)
2009{
2010 struct pool *pool = tc->pool;
2011 dm_block_t block = get_bio_block(tc, bio);
2012 struct dm_bio_prison_cell *cell;
2013 struct dm_cell_key key;
2014
2015 /*
2016 * If cell is already occupied, then the block is already
2017 * being provisioned so we have nothing further to do here.
2018 */
2019 build_virtual_key(tc->td, block, &key);
2020 if (bio_detain(pool, &key, bio, &cell))
2021 return;
2022
2023 process_cell(tc, cell);
2024}
2025
2026static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
2027 struct dm_bio_prison_cell *cell)
2028{
2029 int r;
2030 int rw = bio_data_dir(bio);
2031 dm_block_t block = get_bio_block(tc, bio);
2032 struct dm_thin_lookup_result lookup_result;
2033
2034 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
2035 switch (r) {
2036 case 0:
2037 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
2038 handle_unserviceable_bio(tc->pool, bio);
2039 if (cell)
2040 cell_defer_no_holder(tc, cell);
2041 } else {
2042 inc_all_io_entry(tc->pool, bio);
2043 remap_and_issue(tc, bio, lookup_result.block);
2044 if (cell)
2045 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
2046 }
2047 break;
2048
2049 case -ENODATA:
2050 if (cell)
2051 cell_defer_no_holder(tc, cell);
2052 if (rw != READ) {
2053 handle_unserviceable_bio(tc->pool, bio);
2054 break;
2055 }
2056
2057 if (tc->origin_dev) {
2058 inc_all_io_entry(tc->pool, bio);
2059 remap_to_origin_and_issue(tc, bio);
2060 break;
2061 }
2062
2063 zero_fill_bio(bio);
2064 bio_endio(bio);
2065 break;
2066
2067 default:
2068 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2069 __func__, r);
2070 if (cell)
2071 cell_defer_no_holder(tc, cell);
2072 bio_io_error(bio);
2073 break;
2074 }
2075}
2076
2077static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
2078{
2079 __process_bio_read_only(tc, bio, NULL);
2080}
2081
2082static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2083{
2084 __process_bio_read_only(tc, cell->holder, cell);
2085}
2086
2087static void process_bio_success(struct thin_c *tc, struct bio *bio)
2088{
2089 bio_endio(bio);
2090}
2091
2092static void process_bio_fail(struct thin_c *tc, struct bio *bio)
2093{
2094 bio_io_error(bio);
2095}
2096
2097static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2098{
2099 cell_success(tc->pool, cell);
2100}
2101
2102static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2103{
2104 cell_error(tc->pool, cell);
2105}
2106
2107/*
2108 * FIXME: should we also commit due to size of transaction, measured in
2109 * metadata blocks?
2110 */
2111static int need_commit_due_to_time(struct pool *pool)
2112{
2113 return !time_in_range(jiffies, pool->last_commit_jiffies,
2114 pool->last_commit_jiffies + COMMIT_PERIOD);
2115}
2116
2117#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2118#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2119
2120static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2121{
2122 struct rb_node **rbp, *parent;
2123 struct dm_thin_endio_hook *pbd;
2124 sector_t bi_sector = bio->bi_iter.bi_sector;
2125
2126 rbp = &tc->sort_bio_list.rb_node;
2127 parent = NULL;
2128 while (*rbp) {
2129 parent = *rbp;
2130 pbd = thin_pbd(parent);
2131
2132 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2133 rbp = &(*rbp)->rb_left;
2134 else
2135 rbp = &(*rbp)->rb_right;
2136 }
2137
2138 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2139 rb_link_node(&pbd->rb_node, parent, rbp);
2140 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2141}
2142
2143static void __extract_sorted_bios(struct thin_c *tc)
2144{
2145 struct rb_node *node;
2146 struct dm_thin_endio_hook *pbd;
2147 struct bio *bio;
2148
2149 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2150 pbd = thin_pbd(node);
2151 bio = thin_bio(pbd);
2152
2153 bio_list_add(&tc->deferred_bio_list, bio);
2154 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2155 }
2156
2157 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2158}
2159
2160static void __sort_thin_deferred_bios(struct thin_c *tc)
2161{
2162 struct bio *bio;
2163 struct bio_list bios;
2164
2165 bio_list_init(&bios);
2166 bio_list_merge(&bios, &tc->deferred_bio_list);
2167 bio_list_init(&tc->deferred_bio_list);
2168
2169 /* Sort deferred_bio_list using rb-tree */
2170 while ((bio = bio_list_pop(&bios)))
2171 __thin_bio_rb_add(tc, bio);
2172
2173 /*
2174 * Transfer the sorted bios in sort_bio_list back to
2175 * deferred_bio_list to allow lockless submission of
2176 * all bios.
2177 */
2178 __extract_sorted_bios(tc);
2179}
2180
2181static void process_thin_deferred_bios(struct thin_c *tc)
2182{
2183 struct pool *pool = tc->pool;
2184 struct bio *bio;
2185 struct bio_list bios;
2186 struct blk_plug plug;
2187 unsigned int count = 0;
2188
2189 if (tc->requeue_mode) {
2190 error_thin_bio_list(tc, &tc->deferred_bio_list,
2191 BLK_STS_DM_REQUEUE);
2192 return;
2193 }
2194
2195 bio_list_init(&bios);
2196
2197 spin_lock_irq(&tc->lock);
2198
2199 if (bio_list_empty(&tc->deferred_bio_list)) {
2200 spin_unlock_irq(&tc->lock);
2201 return;
2202 }
2203
2204 __sort_thin_deferred_bios(tc);
2205
2206 bio_list_merge(&bios, &tc->deferred_bio_list);
2207 bio_list_init(&tc->deferred_bio_list);
2208
2209 spin_unlock_irq(&tc->lock);
2210
2211 blk_start_plug(&plug);
2212 while ((bio = bio_list_pop(&bios))) {
2213 /*
2214 * If we've got no free new_mapping structs, and processing
2215 * this bio might require one, we pause until there are some
2216 * prepared mappings to process.
2217 */
2218 if (ensure_next_mapping(pool)) {
2219 spin_lock_irq(&tc->lock);
2220 bio_list_add(&tc->deferred_bio_list, bio);
2221 bio_list_merge(&tc->deferred_bio_list, &bios);
2222 spin_unlock_irq(&tc->lock);
2223 break;
2224 }
2225
2226 if (bio_op(bio) == REQ_OP_DISCARD)
2227 pool->process_discard(tc, bio);
2228 else
2229 pool->process_bio(tc, bio);
2230
2231 if ((count++ & 127) == 0) {
2232 throttle_work_update(&pool->throttle);
2233 dm_pool_issue_prefetches(pool->pmd);
2234 }
2235 cond_resched();
2236 }
2237 blk_finish_plug(&plug);
2238}
2239
2240static int cmp_cells(const void *lhs, const void *rhs)
2241{
2242 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2243 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2244
2245 BUG_ON(!lhs_cell->holder);
2246 BUG_ON(!rhs_cell->holder);
2247
2248 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2249 return -1;
2250
2251 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2252 return 1;
2253
2254 return 0;
2255}
2256
2257static unsigned int sort_cells(struct pool *pool, struct list_head *cells)
2258{
2259 unsigned int count = 0;
2260 struct dm_bio_prison_cell *cell, *tmp;
2261
2262 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2263 if (count >= CELL_SORT_ARRAY_SIZE)
2264 break;
2265
2266 pool->cell_sort_array[count++] = cell;
2267 list_del(&cell->user_list);
2268 }
2269
2270 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2271
2272 return count;
2273}
2274
2275static void process_thin_deferred_cells(struct thin_c *tc)
2276{
2277 struct pool *pool = tc->pool;
2278 struct list_head cells;
2279 struct dm_bio_prison_cell *cell;
2280 unsigned int i, j, count;
2281
2282 INIT_LIST_HEAD(&cells);
2283
2284 spin_lock_irq(&tc->lock);
2285 list_splice_init(&tc->deferred_cells, &cells);
2286 spin_unlock_irq(&tc->lock);
2287
2288 if (list_empty(&cells))
2289 return;
2290
2291 do {
2292 count = sort_cells(tc->pool, &cells);
2293
2294 for (i = 0; i < count; i++) {
2295 cell = pool->cell_sort_array[i];
2296 BUG_ON(!cell->holder);
2297
2298 /*
2299 * If we've got no free new_mapping structs, and processing
2300 * this bio might require one, we pause until there are some
2301 * prepared mappings to process.
2302 */
2303 if (ensure_next_mapping(pool)) {
2304 for (j = i; j < count; j++)
2305 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2306
2307 spin_lock_irq(&tc->lock);
2308 list_splice(&cells, &tc->deferred_cells);
2309 spin_unlock_irq(&tc->lock);
2310 return;
2311 }
2312
2313 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2314 pool->process_discard_cell(tc, cell);
2315 else
2316 pool->process_cell(tc, cell);
2317 }
2318 cond_resched();
2319 } while (!list_empty(&cells));
2320}
2321
2322static void thin_get(struct thin_c *tc);
2323static void thin_put(struct thin_c *tc);
2324
2325/*
2326 * We can't hold rcu_read_lock() around code that can block. So we
2327 * find a thin with the rcu lock held; bump a refcount; then drop
2328 * the lock.
2329 */
2330static struct thin_c *get_first_thin(struct pool *pool)
2331{
2332 struct thin_c *tc = NULL;
2333
2334 rcu_read_lock();
2335 tc = list_first_or_null_rcu(&pool->active_thins, struct thin_c, list);
2336 if (tc)
2337 thin_get(tc);
2338 rcu_read_unlock();
2339
2340 return tc;
2341}
2342
2343static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2344{
2345 struct thin_c *old_tc = tc;
2346
2347 rcu_read_lock();
2348 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2349 thin_get(tc);
2350 thin_put(old_tc);
2351 rcu_read_unlock();
2352 return tc;
2353 }
2354 thin_put(old_tc);
2355 rcu_read_unlock();
2356
2357 return NULL;
2358}
2359
2360static void process_deferred_bios(struct pool *pool)
2361{
2362 struct bio *bio;
2363 struct bio_list bios, bio_completions;
2364 struct thin_c *tc;
2365
2366 tc = get_first_thin(pool);
2367 while (tc) {
2368 process_thin_deferred_cells(tc);
2369 process_thin_deferred_bios(tc);
2370 tc = get_next_thin(pool, tc);
2371 }
2372
2373 /*
2374 * If there are any deferred flush bios, we must commit the metadata
2375 * before issuing them or signaling their completion.
2376 */
2377 bio_list_init(&bios);
2378 bio_list_init(&bio_completions);
2379
2380 spin_lock_irq(&pool->lock);
2381 bio_list_merge(&bios, &pool->deferred_flush_bios);
2382 bio_list_init(&pool->deferred_flush_bios);
2383
2384 bio_list_merge(&bio_completions, &pool->deferred_flush_completions);
2385 bio_list_init(&pool->deferred_flush_completions);
2386 spin_unlock_irq(&pool->lock);
2387
2388 if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) &&
2389 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2390 return;
2391
2392 if (commit(pool)) {
2393 bio_list_merge(&bios, &bio_completions);
2394
2395 while ((bio = bio_list_pop(&bios)))
2396 bio_io_error(bio);
2397 return;
2398 }
2399 pool->last_commit_jiffies = jiffies;
2400
2401 while ((bio = bio_list_pop(&bio_completions)))
2402 bio_endio(bio);
2403
2404 while ((bio = bio_list_pop(&bios))) {
2405 /*
2406 * The data device was flushed as part of metadata commit,
2407 * so complete redundant flushes immediately.
2408 */
2409 if (bio->bi_opf & REQ_PREFLUSH)
2410 bio_endio(bio);
2411 else
2412 dm_submit_bio_remap(bio, NULL);
2413 }
2414}
2415
2416static void do_worker(struct work_struct *ws)
2417{
2418 struct pool *pool = container_of(ws, struct pool, worker);
2419
2420 throttle_work_start(&pool->throttle);
2421 dm_pool_issue_prefetches(pool->pmd);
2422 throttle_work_update(&pool->throttle);
2423 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2424 throttle_work_update(&pool->throttle);
2425 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2426 throttle_work_update(&pool->throttle);
2427 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2428 throttle_work_update(&pool->throttle);
2429 process_deferred_bios(pool);
2430 throttle_work_complete(&pool->throttle);
2431}
2432
2433/*
2434 * We want to commit periodically so that not too much
2435 * unwritten data builds up.
2436 */
2437static void do_waker(struct work_struct *ws)
2438{
2439 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2440
2441 wake_worker(pool);
2442 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2443}
2444
2445/*
2446 * We're holding onto IO to allow userland time to react. After the
2447 * timeout either the pool will have been resized (and thus back in
2448 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2449 */
2450static void do_no_space_timeout(struct work_struct *ws)
2451{
2452 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2453 no_space_timeout);
2454
2455 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2456 pool->pf.error_if_no_space = true;
2457 notify_of_pool_mode_change(pool);
2458 error_retry_list_with_code(pool, BLK_STS_NOSPC);
2459 }
2460}
2461
2462/*----------------------------------------------------------------*/
2463
2464struct pool_work {
2465 struct work_struct worker;
2466 struct completion complete;
2467};
2468
2469static struct pool_work *to_pool_work(struct work_struct *ws)
2470{
2471 return container_of(ws, struct pool_work, worker);
2472}
2473
2474static void pool_work_complete(struct pool_work *pw)
2475{
2476 complete(&pw->complete);
2477}
2478
2479static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2480 void (*fn)(struct work_struct *))
2481{
2482 INIT_WORK_ONSTACK(&pw->worker, fn);
2483 init_completion(&pw->complete);
2484 queue_work(pool->wq, &pw->worker);
2485 wait_for_completion(&pw->complete);
2486 destroy_work_on_stack(&pw->worker);
2487}
2488
2489/*----------------------------------------------------------------*/
2490
2491struct noflush_work {
2492 struct pool_work pw;
2493 struct thin_c *tc;
2494};
2495
2496static struct noflush_work *to_noflush(struct work_struct *ws)
2497{
2498 return container_of(to_pool_work(ws), struct noflush_work, pw);
2499}
2500
2501static void do_noflush_start(struct work_struct *ws)
2502{
2503 struct noflush_work *w = to_noflush(ws);
2504
2505 w->tc->requeue_mode = true;
2506 requeue_io(w->tc);
2507 pool_work_complete(&w->pw);
2508}
2509
2510static void do_noflush_stop(struct work_struct *ws)
2511{
2512 struct noflush_work *w = to_noflush(ws);
2513
2514 w->tc->requeue_mode = false;
2515 pool_work_complete(&w->pw);
2516}
2517
2518static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2519{
2520 struct noflush_work w;
2521
2522 w.tc = tc;
2523 pool_work_wait(&w.pw, tc->pool, fn);
2524}
2525
2526/*----------------------------------------------------------------*/
2527
2528static void set_discard_callbacks(struct pool *pool)
2529{
2530 struct pool_c *pt = pool->ti->private;
2531
2532 if (pt->adjusted_pf.discard_passdown) {
2533 pool->process_discard_cell = process_discard_cell_passdown;
2534 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2535 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2536 } else {
2537 pool->process_discard_cell = process_discard_cell_no_passdown;
2538 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2539 }
2540}
2541
2542static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2543{
2544 struct pool_c *pt = pool->ti->private;
2545 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2546 enum pool_mode old_mode = get_pool_mode(pool);
2547 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
2548
2549 /*
2550 * Never allow the pool to transition to PM_WRITE mode if user
2551 * intervention is required to verify metadata and data consistency.
2552 */
2553 if (new_mode == PM_WRITE && needs_check) {
2554 DMERR("%s: unable to switch pool to write mode until repaired.",
2555 dm_device_name(pool->pool_md));
2556 if (old_mode != new_mode)
2557 new_mode = old_mode;
2558 else
2559 new_mode = PM_READ_ONLY;
2560 }
2561 /*
2562 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2563 * not going to recover without a thin_repair. So we never let the
2564 * pool move out of the old mode.
2565 */
2566 if (old_mode == PM_FAIL)
2567 new_mode = old_mode;
2568
2569 switch (new_mode) {
2570 case PM_FAIL:
2571 dm_pool_metadata_read_only(pool->pmd);
2572 pool->process_bio = process_bio_fail;
2573 pool->process_discard = process_bio_fail;
2574 pool->process_cell = process_cell_fail;
2575 pool->process_discard_cell = process_cell_fail;
2576 pool->process_prepared_mapping = process_prepared_mapping_fail;
2577 pool->process_prepared_discard = process_prepared_discard_fail;
2578
2579 error_retry_list(pool);
2580 break;
2581
2582 case PM_OUT_OF_METADATA_SPACE:
2583 case PM_READ_ONLY:
2584 dm_pool_metadata_read_only(pool->pmd);
2585 pool->process_bio = process_bio_read_only;
2586 pool->process_discard = process_bio_success;
2587 pool->process_cell = process_cell_read_only;
2588 pool->process_discard_cell = process_cell_success;
2589 pool->process_prepared_mapping = process_prepared_mapping_fail;
2590 pool->process_prepared_discard = process_prepared_discard_success;
2591
2592 error_retry_list(pool);
2593 break;
2594
2595 case PM_OUT_OF_DATA_SPACE:
2596 /*
2597 * Ideally we'd never hit this state; the low water mark
2598 * would trigger userland to extend the pool before we
2599 * completely run out of data space. However, many small
2600 * IOs to unprovisioned space can consume data space at an
2601 * alarming rate. Adjust your low water mark if you're
2602 * frequently seeing this mode.
2603 */
2604 pool->out_of_data_space = true;
2605 pool->process_bio = process_bio_read_only;
2606 pool->process_discard = process_discard_bio;
2607 pool->process_cell = process_cell_read_only;
2608 pool->process_prepared_mapping = process_prepared_mapping;
2609 set_discard_callbacks(pool);
2610
2611 if (!pool->pf.error_if_no_space && no_space_timeout)
2612 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2613 break;
2614
2615 case PM_WRITE:
2616 if (old_mode == PM_OUT_OF_DATA_SPACE)
2617 cancel_delayed_work_sync(&pool->no_space_timeout);
2618 pool->out_of_data_space = false;
2619 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2620 dm_pool_metadata_read_write(pool->pmd);
2621 pool->process_bio = process_bio;
2622 pool->process_discard = process_discard_bio;
2623 pool->process_cell = process_cell;
2624 pool->process_prepared_mapping = process_prepared_mapping;
2625 set_discard_callbacks(pool);
2626 break;
2627 }
2628
2629 pool->pf.mode = new_mode;
2630 /*
2631 * The pool mode may have changed, sync it so bind_control_target()
2632 * doesn't cause an unexpected mode transition on resume.
2633 */
2634 pt->adjusted_pf.mode = new_mode;
2635
2636 if (old_mode != new_mode)
2637 notify_of_pool_mode_change(pool);
2638}
2639
2640static void abort_transaction(struct pool *pool)
2641{
2642 const char *dev_name = dm_device_name(pool->pool_md);
2643
2644 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2645 if (dm_pool_abort_metadata(pool->pmd)) {
2646 DMERR("%s: failed to abort metadata transaction", dev_name);
2647 set_pool_mode(pool, PM_FAIL);
2648 }
2649
2650 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2651 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2652 set_pool_mode(pool, PM_FAIL);
2653 }
2654}
2655
2656static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2657{
2658 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2659 dm_device_name(pool->pool_md), op, r);
2660
2661 abort_transaction(pool);
2662 set_pool_mode(pool, PM_READ_ONLY);
2663}
2664
2665/*----------------------------------------------------------------*/
2666
2667/*
2668 * Mapping functions.
2669 */
2670
2671/*
2672 * Called only while mapping a thin bio to hand it over to the workqueue.
2673 */
2674static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2675{
2676 struct pool *pool = tc->pool;
2677
2678 spin_lock_irq(&tc->lock);
2679 bio_list_add(&tc->deferred_bio_list, bio);
2680 spin_unlock_irq(&tc->lock);
2681
2682 wake_worker(pool);
2683}
2684
2685static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2686{
2687 struct pool *pool = tc->pool;
2688
2689 throttle_lock(&pool->throttle);
2690 thin_defer_bio(tc, bio);
2691 throttle_unlock(&pool->throttle);
2692}
2693
2694static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2695{
2696 struct pool *pool = tc->pool;
2697
2698 throttle_lock(&pool->throttle);
2699 spin_lock_irq(&tc->lock);
2700 list_add_tail(&cell->user_list, &tc->deferred_cells);
2701 spin_unlock_irq(&tc->lock);
2702 throttle_unlock(&pool->throttle);
2703
2704 wake_worker(pool);
2705}
2706
2707static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2708{
2709 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2710
2711 h->tc = tc;
2712 h->shared_read_entry = NULL;
2713 h->all_io_entry = NULL;
2714 h->overwrite_mapping = NULL;
2715 h->cell = NULL;
2716}
2717
2718/*
2719 * Non-blocking function called from the thin target's map function.
2720 */
2721static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2722{
2723 int r;
2724 struct thin_c *tc = ti->private;
2725 dm_block_t block = get_bio_block(tc, bio);
2726 struct dm_thin_device *td = tc->td;
2727 struct dm_thin_lookup_result result;
2728 struct dm_bio_prison_cell *virt_cell, *data_cell;
2729 struct dm_cell_key key;
2730
2731 thin_hook_bio(tc, bio);
2732
2733 if (tc->requeue_mode) {
2734 bio->bi_status = BLK_STS_DM_REQUEUE;
2735 bio_endio(bio);
2736 return DM_MAPIO_SUBMITTED;
2737 }
2738
2739 if (get_pool_mode(tc->pool) == PM_FAIL) {
2740 bio_io_error(bio);
2741 return DM_MAPIO_SUBMITTED;
2742 }
2743
2744 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
2745 thin_defer_bio_with_throttle(tc, bio);
2746 return DM_MAPIO_SUBMITTED;
2747 }
2748
2749 /*
2750 * We must hold the virtual cell before doing the lookup, otherwise
2751 * there's a race with discard.
2752 */
2753 build_virtual_key(tc->td, block, &key);
2754 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2755 return DM_MAPIO_SUBMITTED;
2756
2757 r = dm_thin_find_block(td, block, 0, &result);
2758
2759 /*
2760 * Note that we defer readahead too.
2761 */
2762 switch (r) {
2763 case 0:
2764 if (unlikely(result.shared)) {
2765 /*
2766 * We have a race condition here between the
2767 * result.shared value returned by the lookup and
2768 * snapshot creation, which may cause new
2769 * sharing.
2770 *
2771 * To avoid this always quiesce the origin before
2772 * taking the snap. You want to do this anyway to
2773 * ensure a consistent application view
2774 * (i.e. lockfs).
2775 *
2776 * More distant ancestors are irrelevant. The
2777 * shared flag will be set in their case.
2778 */
2779 thin_defer_cell(tc, virt_cell);
2780 return DM_MAPIO_SUBMITTED;
2781 }
2782
2783 build_data_key(tc->td, result.block, &key);
2784 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2785 cell_defer_no_holder(tc, virt_cell);
2786 return DM_MAPIO_SUBMITTED;
2787 }
2788
2789 inc_all_io_entry(tc->pool, bio);
2790 cell_defer_no_holder(tc, data_cell);
2791 cell_defer_no_holder(tc, virt_cell);
2792
2793 remap(tc, bio, result.block);
2794 return DM_MAPIO_REMAPPED;
2795
2796 case -ENODATA:
2797 case -EWOULDBLOCK:
2798 thin_defer_cell(tc, virt_cell);
2799 return DM_MAPIO_SUBMITTED;
2800
2801 default:
2802 /*
2803 * Must always call bio_io_error on failure.
2804 * dm_thin_find_block can fail with -EINVAL if the
2805 * pool is switched to fail-io mode.
2806 */
2807 bio_io_error(bio);
2808 cell_defer_no_holder(tc, virt_cell);
2809 return DM_MAPIO_SUBMITTED;
2810 }
2811}
2812
2813static void requeue_bios(struct pool *pool)
2814{
2815 struct thin_c *tc;
2816
2817 rcu_read_lock();
2818 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2819 spin_lock_irq(&tc->lock);
2820 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2821 bio_list_init(&tc->retry_on_resume_list);
2822 spin_unlock_irq(&tc->lock);
2823 }
2824 rcu_read_unlock();
2825}
2826
2827/*
2828 *--------------------------------------------------------------
2829 * Binding of control targets to a pool object
2830 *--------------------------------------------------------------
2831 */
2832static bool is_factor(sector_t block_size, uint32_t n)
2833{
2834 return !sector_div(block_size, n);
2835}
2836
2837/*
2838 * If discard_passdown was enabled verify that the data device
2839 * supports discards. Disable discard_passdown if not.
2840 */
2841static void disable_discard_passdown_if_not_supported(struct pool_c *pt)
2842{
2843 struct pool *pool = pt->pool;
2844 struct block_device *data_bdev = pt->data_dev->bdev;
2845 struct queue_limits *data_limits = bdev_limits(data_bdev);
2846 const char *reason = NULL;
2847
2848 if (!pt->adjusted_pf.discard_passdown)
2849 return;
2850
2851 if (!bdev_max_discard_sectors(pt->data_dev->bdev))
2852 reason = "discard unsupported";
2853
2854 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2855 reason = "max discard sectors smaller than a block";
2856
2857 if (reason) {
2858 DMWARN("Data device (%pg) %s: Disabling discard passdown.", data_bdev, reason);
2859 pt->adjusted_pf.discard_passdown = false;
2860 }
2861}
2862
2863static int bind_control_target(struct pool *pool, struct dm_target *ti)
2864{
2865 struct pool_c *pt = ti->private;
2866
2867 /*
2868 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2869 */
2870 enum pool_mode old_mode = get_pool_mode(pool);
2871 enum pool_mode new_mode = pt->adjusted_pf.mode;
2872
2873 /*
2874 * Don't change the pool's mode until set_pool_mode() below.
2875 * Otherwise the pool's process_* function pointers may
2876 * not match the desired pool mode.
2877 */
2878 pt->adjusted_pf.mode = old_mode;
2879
2880 pool->ti = ti;
2881 pool->pf = pt->adjusted_pf;
2882 pool->low_water_blocks = pt->low_water_blocks;
2883
2884 set_pool_mode(pool, new_mode);
2885
2886 return 0;
2887}
2888
2889static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2890{
2891 if (pool->ti == ti)
2892 pool->ti = NULL;
2893}
2894
2895/*
2896 *--------------------------------------------------------------
2897 * Pool creation
2898 *--------------------------------------------------------------
2899 */
2900/* Initialize pool features. */
2901static void pool_features_init(struct pool_features *pf)
2902{
2903 pf->mode = PM_WRITE;
2904 pf->zero_new_blocks = true;
2905 pf->discard_enabled = true;
2906 pf->discard_passdown = true;
2907 pf->error_if_no_space = false;
2908}
2909
2910static void __pool_destroy(struct pool *pool)
2911{
2912 __pool_table_remove(pool);
2913
2914 vfree(pool->cell_sort_array);
2915 if (dm_pool_metadata_close(pool->pmd) < 0)
2916 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2917
2918 dm_bio_prison_destroy(pool->prison);
2919 dm_kcopyd_client_destroy(pool->copier);
2920
2921 cancel_delayed_work_sync(&pool->waker);
2922 cancel_delayed_work_sync(&pool->no_space_timeout);
2923 if (pool->wq)
2924 destroy_workqueue(pool->wq);
2925
2926 if (pool->next_mapping)
2927 mempool_free(pool->next_mapping, &pool->mapping_pool);
2928 mempool_exit(&pool->mapping_pool);
2929 dm_deferred_set_destroy(pool->shared_read_ds);
2930 dm_deferred_set_destroy(pool->all_io_ds);
2931 kfree(pool);
2932}
2933
2934static struct kmem_cache *_new_mapping_cache;
2935
2936static struct pool *pool_create(struct mapped_device *pool_md,
2937 struct block_device *metadata_dev,
2938 struct block_device *data_dev,
2939 unsigned long block_size,
2940 int read_only, char **error)
2941{
2942 int r;
2943 void *err_p;
2944 struct pool *pool;
2945 struct dm_pool_metadata *pmd;
2946 bool format_device = read_only ? false : true;
2947
2948 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2949 if (IS_ERR(pmd)) {
2950 *error = "Error creating metadata object";
2951 return ERR_CAST(pmd);
2952 }
2953
2954 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
2955 if (!pool) {
2956 *error = "Error allocating memory for pool";
2957 err_p = ERR_PTR(-ENOMEM);
2958 goto bad_pool;
2959 }
2960
2961 pool->pmd = pmd;
2962 pool->sectors_per_block = block_size;
2963 if (block_size & (block_size - 1))
2964 pool->sectors_per_block_shift = -1;
2965 else
2966 pool->sectors_per_block_shift = __ffs(block_size);
2967 pool->low_water_blocks = 0;
2968 pool_features_init(&pool->pf);
2969 pool->prison = dm_bio_prison_create();
2970 if (!pool->prison) {
2971 *error = "Error creating pool's bio prison";
2972 err_p = ERR_PTR(-ENOMEM);
2973 goto bad_prison;
2974 }
2975
2976 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2977 if (IS_ERR(pool->copier)) {
2978 r = PTR_ERR(pool->copier);
2979 *error = "Error creating pool's kcopyd client";
2980 err_p = ERR_PTR(r);
2981 goto bad_kcopyd_client;
2982 }
2983
2984 /*
2985 * Create singlethreaded workqueue that will service all devices
2986 * that use this metadata.
2987 */
2988 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2989 if (!pool->wq) {
2990 *error = "Error creating pool's workqueue";
2991 err_p = ERR_PTR(-ENOMEM);
2992 goto bad_wq;
2993 }
2994
2995 throttle_init(&pool->throttle);
2996 INIT_WORK(&pool->worker, do_worker);
2997 INIT_DELAYED_WORK(&pool->waker, do_waker);
2998 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2999 spin_lock_init(&pool->lock);
3000 bio_list_init(&pool->deferred_flush_bios);
3001 bio_list_init(&pool->deferred_flush_completions);
3002 INIT_LIST_HEAD(&pool->prepared_mappings);
3003 INIT_LIST_HEAD(&pool->prepared_discards);
3004 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
3005 INIT_LIST_HEAD(&pool->active_thins);
3006 pool->low_water_triggered = false;
3007 pool->suspended = true;
3008 pool->out_of_data_space = false;
3009
3010 pool->shared_read_ds = dm_deferred_set_create();
3011 if (!pool->shared_read_ds) {
3012 *error = "Error creating pool's shared read deferred set";
3013 err_p = ERR_PTR(-ENOMEM);
3014 goto bad_shared_read_ds;
3015 }
3016
3017 pool->all_io_ds = dm_deferred_set_create();
3018 if (!pool->all_io_ds) {
3019 *error = "Error creating pool's all io deferred set";
3020 err_p = ERR_PTR(-ENOMEM);
3021 goto bad_all_io_ds;
3022 }
3023
3024 pool->next_mapping = NULL;
3025 r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE,
3026 _new_mapping_cache);
3027 if (r) {
3028 *error = "Error creating pool's mapping mempool";
3029 err_p = ERR_PTR(r);
3030 goto bad_mapping_pool;
3031 }
3032
3033 pool->cell_sort_array =
3034 vmalloc(array_size(CELL_SORT_ARRAY_SIZE,
3035 sizeof(*pool->cell_sort_array)));
3036 if (!pool->cell_sort_array) {
3037 *error = "Error allocating cell sort array";
3038 err_p = ERR_PTR(-ENOMEM);
3039 goto bad_sort_array;
3040 }
3041
3042 pool->ref_count = 1;
3043 pool->last_commit_jiffies = jiffies;
3044 pool->pool_md = pool_md;
3045 pool->md_dev = metadata_dev;
3046 pool->data_dev = data_dev;
3047 __pool_table_insert(pool);
3048
3049 return pool;
3050
3051bad_sort_array:
3052 mempool_exit(&pool->mapping_pool);
3053bad_mapping_pool:
3054 dm_deferred_set_destroy(pool->all_io_ds);
3055bad_all_io_ds:
3056 dm_deferred_set_destroy(pool->shared_read_ds);
3057bad_shared_read_ds:
3058 destroy_workqueue(pool->wq);
3059bad_wq:
3060 dm_kcopyd_client_destroy(pool->copier);
3061bad_kcopyd_client:
3062 dm_bio_prison_destroy(pool->prison);
3063bad_prison:
3064 kfree(pool);
3065bad_pool:
3066 if (dm_pool_metadata_close(pmd))
3067 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
3068
3069 return err_p;
3070}
3071
3072static void __pool_inc(struct pool *pool)
3073{
3074 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3075 pool->ref_count++;
3076}
3077
3078static void __pool_dec(struct pool *pool)
3079{
3080 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3081 BUG_ON(!pool->ref_count);
3082 if (!--pool->ref_count)
3083 __pool_destroy(pool);
3084}
3085
3086static struct pool *__pool_find(struct mapped_device *pool_md,
3087 struct block_device *metadata_dev,
3088 struct block_device *data_dev,
3089 unsigned long block_size, int read_only,
3090 char **error, int *created)
3091{
3092 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
3093
3094 if (pool) {
3095 if (pool->pool_md != pool_md) {
3096 *error = "metadata device already in use by a pool";
3097 return ERR_PTR(-EBUSY);
3098 }
3099 if (pool->data_dev != data_dev) {
3100 *error = "data device already in use by a pool";
3101 return ERR_PTR(-EBUSY);
3102 }
3103 __pool_inc(pool);
3104
3105 } else {
3106 pool = __pool_table_lookup(pool_md);
3107 if (pool) {
3108 if (pool->md_dev != metadata_dev || pool->data_dev != data_dev) {
3109 *error = "different pool cannot replace a pool";
3110 return ERR_PTR(-EINVAL);
3111 }
3112 __pool_inc(pool);
3113
3114 } else {
3115 pool = pool_create(pool_md, metadata_dev, data_dev, block_size, read_only, error);
3116 *created = 1;
3117 }
3118 }
3119
3120 return pool;
3121}
3122
3123/*
3124 *--------------------------------------------------------------
3125 * Pool target methods
3126 *--------------------------------------------------------------
3127 */
3128static void pool_dtr(struct dm_target *ti)
3129{
3130 struct pool_c *pt = ti->private;
3131
3132 mutex_lock(&dm_thin_pool_table.mutex);
3133
3134 unbind_control_target(pt->pool, ti);
3135 __pool_dec(pt->pool);
3136 dm_put_device(ti, pt->metadata_dev);
3137 dm_put_device(ti, pt->data_dev);
3138 kfree(pt);
3139
3140 mutex_unlock(&dm_thin_pool_table.mutex);
3141}
3142
3143static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3144 struct dm_target *ti)
3145{
3146 int r;
3147 unsigned int argc;
3148 const char *arg_name;
3149
3150 static const struct dm_arg _args[] = {
3151 {0, 4, "Invalid number of pool feature arguments"},
3152 };
3153
3154 /*
3155 * No feature arguments supplied.
3156 */
3157 if (!as->argc)
3158 return 0;
3159
3160 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3161 if (r)
3162 return -EINVAL;
3163
3164 while (argc && !r) {
3165 arg_name = dm_shift_arg(as);
3166 argc--;
3167
3168 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3169 pf->zero_new_blocks = false;
3170
3171 else if (!strcasecmp(arg_name, "ignore_discard"))
3172 pf->discard_enabled = false;
3173
3174 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3175 pf->discard_passdown = false;
3176
3177 else if (!strcasecmp(arg_name, "read_only"))
3178 pf->mode = PM_READ_ONLY;
3179
3180 else if (!strcasecmp(arg_name, "error_if_no_space"))
3181 pf->error_if_no_space = true;
3182
3183 else {
3184 ti->error = "Unrecognised pool feature requested";
3185 r = -EINVAL;
3186 break;
3187 }
3188 }
3189
3190 return r;
3191}
3192
3193static void metadata_low_callback(void *context)
3194{
3195 struct pool *pool = context;
3196
3197 DMWARN("%s: reached low water mark for metadata device: sending event.",
3198 dm_device_name(pool->pool_md));
3199
3200 dm_table_event(pool->ti->table);
3201}
3202
3203/*
3204 * We need to flush the data device **before** committing the metadata.
3205 *
3206 * This ensures that the data blocks of any newly inserted mappings are
3207 * properly written to non-volatile storage and won't be lost in case of a
3208 * crash.
3209 *
3210 * Failure to do so can result in data corruption in the case of internal or
3211 * external snapshots and in the case of newly provisioned blocks, when block
3212 * zeroing is enabled.
3213 */
3214static int metadata_pre_commit_callback(void *context)
3215{
3216 struct pool *pool = context;
3217
3218 return blkdev_issue_flush(pool->data_dev);
3219}
3220
3221static sector_t get_dev_size(struct block_device *bdev)
3222{
3223 return bdev_nr_sectors(bdev);
3224}
3225
3226static void warn_if_metadata_device_too_big(struct block_device *bdev)
3227{
3228 sector_t metadata_dev_size = get_dev_size(bdev);
3229
3230 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3231 DMWARN("Metadata device %pg is larger than %u sectors: excess space will not be used.",
3232 bdev, THIN_METADATA_MAX_SECTORS);
3233}
3234
3235static sector_t get_metadata_dev_size(struct block_device *bdev)
3236{
3237 sector_t metadata_dev_size = get_dev_size(bdev);
3238
3239 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3240 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3241
3242 return metadata_dev_size;
3243}
3244
3245static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3246{
3247 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3248
3249 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3250
3251 return metadata_dev_size;
3252}
3253
3254/*
3255 * When a metadata threshold is crossed a dm event is triggered, and
3256 * userland should respond by growing the metadata device. We could let
3257 * userland set the threshold, like we do with the data threshold, but I'm
3258 * not sure they know enough to do this well.
3259 */
3260static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3261{
3262 /*
3263 * 4M is ample for all ops with the possible exception of thin
3264 * device deletion which is harmless if it fails (just retry the
3265 * delete after you've grown the device).
3266 */
3267 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3268
3269 return min((dm_block_t)1024ULL /* 4M */, quarter);
3270}
3271
3272/*
3273 * thin-pool <metadata dev> <data dev>
3274 * <data block size (sectors)>
3275 * <low water mark (blocks)>
3276 * [<#feature args> [<arg>]*]
3277 *
3278 * Optional feature arguments are:
3279 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3280 * ignore_discard: disable discard
3281 * no_discard_passdown: don't pass discards down to the data device
3282 * read_only: Don't allow any changes to be made to the pool metadata.
3283 * error_if_no_space: error IOs, instead of queueing, if no space.
3284 */
3285static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3286{
3287 int r, pool_created = 0;
3288 struct pool_c *pt;
3289 struct pool *pool;
3290 struct pool_features pf;
3291 struct dm_arg_set as;
3292 struct dm_dev *data_dev;
3293 unsigned long block_size;
3294 dm_block_t low_water_blocks;
3295 struct dm_dev *metadata_dev;
3296 blk_mode_t metadata_mode;
3297
3298 /*
3299 * FIXME Remove validation from scope of lock.
3300 */
3301 mutex_lock(&dm_thin_pool_table.mutex);
3302
3303 if (argc < 4) {
3304 ti->error = "Invalid argument count";
3305 r = -EINVAL;
3306 goto out_unlock;
3307 }
3308
3309 as.argc = argc;
3310 as.argv = argv;
3311
3312 /* make sure metadata and data are different devices */
3313 if (!strcmp(argv[0], argv[1])) {
3314 ti->error = "Error setting metadata or data device";
3315 r = -EINVAL;
3316 goto out_unlock;
3317 }
3318
3319 /*
3320 * Set default pool features.
3321 */
3322 pool_features_init(&pf);
3323
3324 dm_consume_args(&as, 4);
3325 r = parse_pool_features(&as, &pf, ti);
3326 if (r)
3327 goto out_unlock;
3328
3329 metadata_mode = BLK_OPEN_READ |
3330 ((pf.mode == PM_READ_ONLY) ? 0 : BLK_OPEN_WRITE);
3331 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3332 if (r) {
3333 ti->error = "Error opening metadata block device";
3334 goto out_unlock;
3335 }
3336 warn_if_metadata_device_too_big(metadata_dev->bdev);
3337
3338 r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE, &data_dev);
3339 if (r) {
3340 ti->error = "Error getting data device";
3341 goto out_metadata;
3342 }
3343
3344 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3345 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3346 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3347 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3348 ti->error = "Invalid block size";
3349 r = -EINVAL;
3350 goto out;
3351 }
3352
3353 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3354 ti->error = "Invalid low water mark";
3355 r = -EINVAL;
3356 goto out;
3357 }
3358
3359 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3360 if (!pt) {
3361 r = -ENOMEM;
3362 goto out;
3363 }
3364
3365 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, data_dev->bdev,
3366 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3367 if (IS_ERR(pool)) {
3368 r = PTR_ERR(pool);
3369 goto out_free_pt;
3370 }
3371
3372 /*
3373 * 'pool_created' reflects whether this is the first table load.
3374 * Top level discard support is not allowed to be changed after
3375 * initial load. This would require a pool reload to trigger thin
3376 * device changes.
3377 */
3378 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3379 ti->error = "Discard support cannot be disabled once enabled";
3380 r = -EINVAL;
3381 goto out_flags_changed;
3382 }
3383
3384 pt->pool = pool;
3385 pt->ti = ti;
3386 pt->metadata_dev = metadata_dev;
3387 pt->data_dev = data_dev;
3388 pt->low_water_blocks = low_water_blocks;
3389 pt->adjusted_pf = pt->requested_pf = pf;
3390 ti->num_flush_bios = 1;
3391 ti->limit_swap_bios = true;
3392
3393 /*
3394 * Only need to enable discards if the pool should pass
3395 * them down to the data device. The thin device's discard
3396 * processing will cause mappings to be removed from the btree.
3397 */
3398 if (pf.discard_enabled && pf.discard_passdown) {
3399 ti->num_discard_bios = 1;
3400 /*
3401 * Setting 'discards_supported' circumvents the normal
3402 * stacking of discard limits (this keeps the pool and
3403 * thin devices' discard limits consistent).
3404 */
3405 ti->discards_supported = true;
3406 ti->max_discard_granularity = true;
3407 }
3408 ti->private = pt;
3409
3410 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
3411 calc_metadata_threshold(pt),
3412 metadata_low_callback,
3413 pool);
3414 if (r) {
3415 ti->error = "Error registering metadata threshold";
3416 goto out_flags_changed;
3417 }
3418
3419 dm_pool_register_pre_commit_callback(pool->pmd,
3420 metadata_pre_commit_callback, pool);
3421
3422 mutex_unlock(&dm_thin_pool_table.mutex);
3423
3424 return 0;
3425
3426out_flags_changed:
3427 __pool_dec(pool);
3428out_free_pt:
3429 kfree(pt);
3430out:
3431 dm_put_device(ti, data_dev);
3432out_metadata:
3433 dm_put_device(ti, metadata_dev);
3434out_unlock:
3435 mutex_unlock(&dm_thin_pool_table.mutex);
3436
3437 return r;
3438}
3439
3440static int pool_map(struct dm_target *ti, struct bio *bio)
3441{
3442 struct pool_c *pt = ti->private;
3443 struct pool *pool = pt->pool;
3444
3445 /*
3446 * As this is a singleton target, ti->begin is always zero.
3447 */
3448 spin_lock_irq(&pool->lock);
3449 bio_set_dev(bio, pt->data_dev->bdev);
3450 spin_unlock_irq(&pool->lock);
3451
3452 return DM_MAPIO_REMAPPED;
3453}
3454
3455static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
3456{
3457 int r;
3458 struct pool_c *pt = ti->private;
3459 struct pool *pool = pt->pool;
3460 sector_t data_size = ti->len;
3461 dm_block_t sb_data_size;
3462
3463 *need_commit = false;
3464
3465 (void) sector_div(data_size, pool->sectors_per_block);
3466
3467 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
3468 if (r) {
3469 DMERR("%s: failed to retrieve data device size",
3470 dm_device_name(pool->pool_md));
3471 return r;
3472 }
3473
3474 if (data_size < sb_data_size) {
3475 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3476 dm_device_name(pool->pool_md),
3477 (unsigned long long)data_size, sb_data_size);
3478 return -EINVAL;
3479
3480 } else if (data_size > sb_data_size) {
3481 if (dm_pool_metadata_needs_check(pool->pmd)) {
3482 DMERR("%s: unable to grow the data device until repaired.",
3483 dm_device_name(pool->pool_md));
3484 return 0;
3485 }
3486
3487 if (sb_data_size)
3488 DMINFO("%s: growing the data device from %llu to %llu blocks",
3489 dm_device_name(pool->pool_md),
3490 sb_data_size, (unsigned long long)data_size);
3491 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3492 if (r) {
3493 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3494 return r;
3495 }
3496
3497 *need_commit = true;
3498 }
3499
3500 return 0;
3501}
3502
3503static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3504{
3505 int r;
3506 struct pool_c *pt = ti->private;
3507 struct pool *pool = pt->pool;
3508 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3509
3510 *need_commit = false;
3511
3512 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3513
3514 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3515 if (r) {
3516 DMERR("%s: failed to retrieve metadata device size",
3517 dm_device_name(pool->pool_md));
3518 return r;
3519 }
3520
3521 if (metadata_dev_size < sb_metadata_dev_size) {
3522 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3523 dm_device_name(pool->pool_md),
3524 metadata_dev_size, sb_metadata_dev_size);
3525 return -EINVAL;
3526
3527 } else if (metadata_dev_size > sb_metadata_dev_size) {
3528 if (dm_pool_metadata_needs_check(pool->pmd)) {
3529 DMERR("%s: unable to grow the metadata device until repaired.",
3530 dm_device_name(pool->pool_md));
3531 return 0;
3532 }
3533
3534 warn_if_metadata_device_too_big(pool->md_dev);
3535 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3536 dm_device_name(pool->pool_md),
3537 sb_metadata_dev_size, metadata_dev_size);
3538
3539 if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE)
3540 set_pool_mode(pool, PM_WRITE);
3541
3542 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3543 if (r) {
3544 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3545 return r;
3546 }
3547
3548 *need_commit = true;
3549 }
3550
3551 return 0;
3552}
3553
3554/*
3555 * Retrieves the number of blocks of the data device from
3556 * the superblock and compares it to the actual device size,
3557 * thus resizing the data device in case it has grown.
3558 *
3559 * This both copes with opening preallocated data devices in the ctr
3560 * being followed by a resume
3561 * -and-
3562 * calling the resume method individually after userspace has
3563 * grown the data device in reaction to a table event.
3564 */
3565static int pool_preresume(struct dm_target *ti)
3566{
3567 int r;
3568 bool need_commit1, need_commit2;
3569 struct pool_c *pt = ti->private;
3570 struct pool *pool = pt->pool;
3571
3572 /*
3573 * Take control of the pool object.
3574 */
3575 r = bind_control_target(pool, ti);
3576 if (r)
3577 goto out;
3578
3579 r = maybe_resize_data_dev(ti, &need_commit1);
3580 if (r)
3581 goto out;
3582
3583 r = maybe_resize_metadata_dev(ti, &need_commit2);
3584 if (r)
3585 goto out;
3586
3587 if (need_commit1 || need_commit2)
3588 (void) commit(pool);
3589out:
3590 /*
3591 * When a thin-pool is PM_FAIL, it cannot be rebuilt if
3592 * bio is in deferred list. Therefore need to return 0
3593 * to allow pool_resume() to flush IO.
3594 */
3595 if (r && get_pool_mode(pool) == PM_FAIL)
3596 r = 0;
3597
3598 return r;
3599}
3600
3601static void pool_suspend_active_thins(struct pool *pool)
3602{
3603 struct thin_c *tc;
3604
3605 /* Suspend all active thin devices */
3606 tc = get_first_thin(pool);
3607 while (tc) {
3608 dm_internal_suspend_noflush(tc->thin_md);
3609 tc = get_next_thin(pool, tc);
3610 }
3611}
3612
3613static void pool_resume_active_thins(struct pool *pool)
3614{
3615 struct thin_c *tc;
3616
3617 /* Resume all active thin devices */
3618 tc = get_first_thin(pool);
3619 while (tc) {
3620 dm_internal_resume(tc->thin_md);
3621 tc = get_next_thin(pool, tc);
3622 }
3623}
3624
3625static void pool_resume(struct dm_target *ti)
3626{
3627 struct pool_c *pt = ti->private;
3628 struct pool *pool = pt->pool;
3629
3630 /*
3631 * Must requeue active_thins' bios and then resume
3632 * active_thins _before_ clearing 'suspend' flag.
3633 */
3634 requeue_bios(pool);
3635 pool_resume_active_thins(pool);
3636
3637 spin_lock_irq(&pool->lock);
3638 pool->low_water_triggered = false;
3639 pool->suspended = false;
3640 spin_unlock_irq(&pool->lock);
3641
3642 do_waker(&pool->waker.work);
3643}
3644
3645static void pool_presuspend(struct dm_target *ti)
3646{
3647 struct pool_c *pt = ti->private;
3648 struct pool *pool = pt->pool;
3649
3650 spin_lock_irq(&pool->lock);
3651 pool->suspended = true;
3652 spin_unlock_irq(&pool->lock);
3653
3654 pool_suspend_active_thins(pool);
3655}
3656
3657static void pool_presuspend_undo(struct dm_target *ti)
3658{
3659 struct pool_c *pt = ti->private;
3660 struct pool *pool = pt->pool;
3661
3662 pool_resume_active_thins(pool);
3663
3664 spin_lock_irq(&pool->lock);
3665 pool->suspended = false;
3666 spin_unlock_irq(&pool->lock);
3667}
3668
3669static void pool_postsuspend(struct dm_target *ti)
3670{
3671 struct pool_c *pt = ti->private;
3672 struct pool *pool = pt->pool;
3673
3674 cancel_delayed_work_sync(&pool->waker);
3675 cancel_delayed_work_sync(&pool->no_space_timeout);
3676 flush_workqueue(pool->wq);
3677 (void) commit(pool);
3678}
3679
3680static int check_arg_count(unsigned int argc, unsigned int args_required)
3681{
3682 if (argc != args_required) {
3683 DMWARN("Message received with %u arguments instead of %u.",
3684 argc, args_required);
3685 return -EINVAL;
3686 }
3687
3688 return 0;
3689}
3690
3691static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3692{
3693 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3694 *dev_id <= MAX_DEV_ID)
3695 return 0;
3696
3697 if (warning)
3698 DMWARN("Message received with invalid device id: %s", arg);
3699
3700 return -EINVAL;
3701}
3702
3703static int process_create_thin_mesg(unsigned int argc, char **argv, struct pool *pool)
3704{
3705 dm_thin_id dev_id;
3706 int r;
3707
3708 r = check_arg_count(argc, 2);
3709 if (r)
3710 return r;
3711
3712 r = read_dev_id(argv[1], &dev_id, 1);
3713 if (r)
3714 return r;
3715
3716 r = dm_pool_create_thin(pool->pmd, dev_id);
3717 if (r) {
3718 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3719 argv[1]);
3720 return r;
3721 }
3722
3723 return 0;
3724}
3725
3726static int process_create_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3727{
3728 dm_thin_id dev_id;
3729 dm_thin_id origin_dev_id;
3730 int r;
3731
3732 r = check_arg_count(argc, 3);
3733 if (r)
3734 return r;
3735
3736 r = read_dev_id(argv[1], &dev_id, 1);
3737 if (r)
3738 return r;
3739
3740 r = read_dev_id(argv[2], &origin_dev_id, 1);
3741 if (r)
3742 return r;
3743
3744 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3745 if (r) {
3746 DMWARN("Creation of new snapshot %s of device %s failed.",
3747 argv[1], argv[2]);
3748 return r;
3749 }
3750
3751 return 0;
3752}
3753
3754static int process_delete_mesg(unsigned int argc, char **argv, struct pool *pool)
3755{
3756 dm_thin_id dev_id;
3757 int r;
3758
3759 r = check_arg_count(argc, 2);
3760 if (r)
3761 return r;
3762
3763 r = read_dev_id(argv[1], &dev_id, 1);
3764 if (r)
3765 return r;
3766
3767 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3768 if (r)
3769 DMWARN("Deletion of thin device %s failed.", argv[1]);
3770
3771 return r;
3772}
3773
3774static int process_set_transaction_id_mesg(unsigned int argc, char **argv, struct pool *pool)
3775{
3776 dm_thin_id old_id, new_id;
3777 int r;
3778
3779 r = check_arg_count(argc, 3);
3780 if (r)
3781 return r;
3782
3783 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3784 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3785 return -EINVAL;
3786 }
3787
3788 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3789 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3790 return -EINVAL;
3791 }
3792
3793 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3794 if (r) {
3795 DMWARN("Failed to change transaction id from %s to %s.",
3796 argv[1], argv[2]);
3797 return r;
3798 }
3799
3800 return 0;
3801}
3802
3803static int process_reserve_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3804{
3805 int r;
3806
3807 r = check_arg_count(argc, 1);
3808 if (r)
3809 return r;
3810
3811 (void) commit(pool);
3812
3813 r = dm_pool_reserve_metadata_snap(pool->pmd);
3814 if (r)
3815 DMWARN("reserve_metadata_snap message failed.");
3816
3817 return r;
3818}
3819
3820static int process_release_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3821{
3822 int r;
3823
3824 r = check_arg_count(argc, 1);
3825 if (r)
3826 return r;
3827
3828 r = dm_pool_release_metadata_snap(pool->pmd);
3829 if (r)
3830 DMWARN("release_metadata_snap message failed.");
3831
3832 return r;
3833}
3834
3835/*
3836 * Messages supported:
3837 * create_thin <dev_id>
3838 * create_snap <dev_id> <origin_id>
3839 * delete <dev_id>
3840 * set_transaction_id <current_trans_id> <new_trans_id>
3841 * reserve_metadata_snap
3842 * release_metadata_snap
3843 */
3844static int pool_message(struct dm_target *ti, unsigned int argc, char **argv,
3845 char *result, unsigned int maxlen)
3846{
3847 int r = -EINVAL;
3848 struct pool_c *pt = ti->private;
3849 struct pool *pool = pt->pool;
3850
3851 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) {
3852 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3853 dm_device_name(pool->pool_md));
3854 return -EOPNOTSUPP;
3855 }
3856
3857 if (!strcasecmp(argv[0], "create_thin"))
3858 r = process_create_thin_mesg(argc, argv, pool);
3859
3860 else if (!strcasecmp(argv[0], "create_snap"))
3861 r = process_create_snap_mesg(argc, argv, pool);
3862
3863 else if (!strcasecmp(argv[0], "delete"))
3864 r = process_delete_mesg(argc, argv, pool);
3865
3866 else if (!strcasecmp(argv[0], "set_transaction_id"))
3867 r = process_set_transaction_id_mesg(argc, argv, pool);
3868
3869 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3870 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3871
3872 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3873 r = process_release_metadata_snap_mesg(argc, argv, pool);
3874
3875 else
3876 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3877
3878 if (!r)
3879 (void) commit(pool);
3880
3881 return r;
3882}
3883
3884static void emit_flags(struct pool_features *pf, char *result,
3885 unsigned int sz, unsigned int maxlen)
3886{
3887 unsigned int count = !pf->zero_new_blocks + !pf->discard_enabled +
3888 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3889 pf->error_if_no_space;
3890 DMEMIT("%u ", count);
3891
3892 if (!pf->zero_new_blocks)
3893 DMEMIT("skip_block_zeroing ");
3894
3895 if (!pf->discard_enabled)
3896 DMEMIT("ignore_discard ");
3897
3898 if (!pf->discard_passdown)
3899 DMEMIT("no_discard_passdown ");
3900
3901 if (pf->mode == PM_READ_ONLY)
3902 DMEMIT("read_only ");
3903
3904 if (pf->error_if_no_space)
3905 DMEMIT("error_if_no_space ");
3906}
3907
3908/*
3909 * Status line is:
3910 * <transaction id> <used metadata sectors>/<total metadata sectors>
3911 * <used data sectors>/<total data sectors> <held metadata root>
3912 * <pool mode> <discard config> <no space config> <needs_check>
3913 */
3914static void pool_status(struct dm_target *ti, status_type_t type,
3915 unsigned int status_flags, char *result, unsigned int maxlen)
3916{
3917 int r;
3918 unsigned int sz = 0;
3919 uint64_t transaction_id;
3920 dm_block_t nr_free_blocks_data;
3921 dm_block_t nr_free_blocks_metadata;
3922 dm_block_t nr_blocks_data;
3923 dm_block_t nr_blocks_metadata;
3924 dm_block_t held_root;
3925 enum pool_mode mode;
3926 char buf[BDEVNAME_SIZE];
3927 char buf2[BDEVNAME_SIZE];
3928 struct pool_c *pt = ti->private;
3929 struct pool *pool = pt->pool;
3930
3931 switch (type) {
3932 case STATUSTYPE_INFO:
3933 if (get_pool_mode(pool) == PM_FAIL) {
3934 DMEMIT("Fail");
3935 break;
3936 }
3937
3938 /* Commit to ensure statistics aren't out-of-date */
3939 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3940 (void) commit(pool);
3941
3942 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3943 if (r) {
3944 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3945 dm_device_name(pool->pool_md), r);
3946 goto err;
3947 }
3948
3949 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3950 if (r) {
3951 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3952 dm_device_name(pool->pool_md), r);
3953 goto err;
3954 }
3955
3956 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3957 if (r) {
3958 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3959 dm_device_name(pool->pool_md), r);
3960 goto err;
3961 }
3962
3963 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3964 if (r) {
3965 DMERR("%s: dm_pool_get_free_block_count returned %d",
3966 dm_device_name(pool->pool_md), r);
3967 goto err;
3968 }
3969
3970 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3971 if (r) {
3972 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3973 dm_device_name(pool->pool_md), r);
3974 goto err;
3975 }
3976
3977 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3978 if (r) {
3979 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3980 dm_device_name(pool->pool_md), r);
3981 goto err;
3982 }
3983
3984 DMEMIT("%llu %llu/%llu %llu/%llu ",
3985 (unsigned long long)transaction_id,
3986 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3987 (unsigned long long)nr_blocks_metadata,
3988 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3989 (unsigned long long)nr_blocks_data);
3990
3991 if (held_root)
3992 DMEMIT("%llu ", held_root);
3993 else
3994 DMEMIT("- ");
3995
3996 mode = get_pool_mode(pool);
3997 if (mode == PM_OUT_OF_DATA_SPACE)
3998 DMEMIT("out_of_data_space ");
3999 else if (is_read_only_pool_mode(mode))
4000 DMEMIT("ro ");
4001 else
4002 DMEMIT("rw ");
4003
4004 if (!pool->pf.discard_enabled)
4005 DMEMIT("ignore_discard ");
4006 else if (pool->pf.discard_passdown)
4007 DMEMIT("discard_passdown ");
4008 else
4009 DMEMIT("no_discard_passdown ");
4010
4011 if (pool->pf.error_if_no_space)
4012 DMEMIT("error_if_no_space ");
4013 else
4014 DMEMIT("queue_if_no_space ");
4015
4016 if (dm_pool_metadata_needs_check(pool->pmd))
4017 DMEMIT("needs_check ");
4018 else
4019 DMEMIT("- ");
4020
4021 DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt));
4022
4023 break;
4024
4025 case STATUSTYPE_TABLE:
4026 DMEMIT("%s %s %lu %llu ",
4027 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
4028 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
4029 (unsigned long)pool->sectors_per_block,
4030 (unsigned long long)pt->low_water_blocks);
4031 emit_flags(&pt->requested_pf, result, sz, maxlen);
4032 break;
4033
4034 case STATUSTYPE_IMA:
4035 *result = '\0';
4036 break;
4037 }
4038 return;
4039
4040err:
4041 DMEMIT("Error");
4042}
4043
4044static int pool_iterate_devices(struct dm_target *ti,
4045 iterate_devices_callout_fn fn, void *data)
4046{
4047 struct pool_c *pt = ti->private;
4048
4049 return fn(ti, pt->data_dev, 0, ti->len, data);
4050}
4051
4052static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
4053{
4054 struct pool_c *pt = ti->private;
4055 struct pool *pool = pt->pool;
4056 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
4057
4058 /*
4059 * If max_sectors is smaller than pool->sectors_per_block adjust it
4060 * to the highest possible power-of-2 factor of pool->sectors_per_block.
4061 * This is especially beneficial when the pool's data device is a RAID
4062 * device that has a full stripe width that matches pool->sectors_per_block
4063 * -- because even though partial RAID stripe-sized IOs will be issued to a
4064 * single RAID stripe; when aggregated they will end on a full RAID stripe
4065 * boundary.. which avoids additional partial RAID stripe writes cascading
4066 */
4067 if (limits->max_sectors < pool->sectors_per_block) {
4068 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
4069 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
4070 limits->max_sectors--;
4071 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
4072 }
4073 }
4074
4075 /*
4076 * If the system-determined stacked limits are compatible with the
4077 * pool's blocksize (io_opt is a factor) do not override them.
4078 */
4079 if (io_opt_sectors < pool->sectors_per_block ||
4080 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
4081 if (is_factor(pool->sectors_per_block, limits->max_sectors))
4082 limits->io_min = limits->max_sectors << SECTOR_SHIFT;
4083 else
4084 limits->io_min = pool->sectors_per_block << SECTOR_SHIFT;
4085 limits->io_opt = pool->sectors_per_block << SECTOR_SHIFT;
4086 }
4087
4088 /*
4089 * pt->adjusted_pf is a staging area for the actual features to use.
4090 * They get transferred to the live pool in bind_control_target()
4091 * called from pool_preresume().
4092 */
4093
4094 if (pt->adjusted_pf.discard_enabled) {
4095 disable_discard_passdown_if_not_supported(pt);
4096 if (!pt->adjusted_pf.discard_passdown)
4097 limits->max_hw_discard_sectors = 0;
4098 /*
4099 * The pool uses the same discard limits as the underlying data
4100 * device. DM core has already set this up.
4101 */
4102 } else {
4103 /*
4104 * Must explicitly disallow stacking discard limits otherwise the
4105 * block layer will stack them if pool's data device has support.
4106 */
4107 limits->discard_granularity = 0;
4108 }
4109}
4110
4111static struct target_type pool_target = {
4112 .name = "thin-pool",
4113 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
4114 DM_TARGET_IMMUTABLE,
4115 .version = {1, 23, 0},
4116 .module = THIS_MODULE,
4117 .ctr = pool_ctr,
4118 .dtr = pool_dtr,
4119 .map = pool_map,
4120 .presuspend = pool_presuspend,
4121 .presuspend_undo = pool_presuspend_undo,
4122 .postsuspend = pool_postsuspend,
4123 .preresume = pool_preresume,
4124 .resume = pool_resume,
4125 .message = pool_message,
4126 .status = pool_status,
4127 .iterate_devices = pool_iterate_devices,
4128 .io_hints = pool_io_hints,
4129};
4130
4131/*
4132 *--------------------------------------------------------------
4133 * Thin target methods
4134 *--------------------------------------------------------------
4135 */
4136static void thin_get(struct thin_c *tc)
4137{
4138 refcount_inc(&tc->refcount);
4139}
4140
4141static void thin_put(struct thin_c *tc)
4142{
4143 if (refcount_dec_and_test(&tc->refcount))
4144 complete(&tc->can_destroy);
4145}
4146
4147static void thin_dtr(struct dm_target *ti)
4148{
4149 struct thin_c *tc = ti->private;
4150
4151 spin_lock_irq(&tc->pool->lock);
4152 list_del_rcu(&tc->list);
4153 spin_unlock_irq(&tc->pool->lock);
4154 synchronize_rcu();
4155
4156 thin_put(tc);
4157 wait_for_completion(&tc->can_destroy);
4158
4159 mutex_lock(&dm_thin_pool_table.mutex);
4160
4161 __pool_dec(tc->pool);
4162 dm_pool_close_thin_device(tc->td);
4163 dm_put_device(ti, tc->pool_dev);
4164 if (tc->origin_dev)
4165 dm_put_device(ti, tc->origin_dev);
4166 kfree(tc);
4167
4168 mutex_unlock(&dm_thin_pool_table.mutex);
4169}
4170
4171/*
4172 * Thin target parameters:
4173 *
4174 * <pool_dev> <dev_id> [origin_dev]
4175 *
4176 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4177 * dev_id: the internal device identifier
4178 * origin_dev: a device external to the pool that should act as the origin
4179 *
4180 * If the pool device has discards disabled, they get disabled for the thin
4181 * device as well.
4182 */
4183static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
4184{
4185 int r;
4186 struct thin_c *tc;
4187 struct dm_dev *pool_dev, *origin_dev;
4188 struct mapped_device *pool_md;
4189
4190 mutex_lock(&dm_thin_pool_table.mutex);
4191
4192 if (argc != 2 && argc != 3) {
4193 ti->error = "Invalid argument count";
4194 r = -EINVAL;
4195 goto out_unlock;
4196 }
4197
4198 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4199 if (!tc) {
4200 ti->error = "Out of memory";
4201 r = -ENOMEM;
4202 goto out_unlock;
4203 }
4204 tc->thin_md = dm_table_get_md(ti->table);
4205 spin_lock_init(&tc->lock);
4206 INIT_LIST_HEAD(&tc->deferred_cells);
4207 bio_list_init(&tc->deferred_bio_list);
4208 bio_list_init(&tc->retry_on_resume_list);
4209 tc->sort_bio_list = RB_ROOT;
4210
4211 if (argc == 3) {
4212 if (!strcmp(argv[0], argv[2])) {
4213 ti->error = "Error setting origin device";
4214 r = -EINVAL;
4215 goto bad_origin_dev;
4216 }
4217
4218 r = dm_get_device(ti, argv[2], BLK_OPEN_READ, &origin_dev);
4219 if (r) {
4220 ti->error = "Error opening origin device";
4221 goto bad_origin_dev;
4222 }
4223 tc->origin_dev = origin_dev;
4224 }
4225
4226 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4227 if (r) {
4228 ti->error = "Error opening pool device";
4229 goto bad_pool_dev;
4230 }
4231 tc->pool_dev = pool_dev;
4232
4233 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4234 ti->error = "Invalid device id";
4235 r = -EINVAL;
4236 goto bad_common;
4237 }
4238
4239 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4240 if (!pool_md) {
4241 ti->error = "Couldn't get pool mapped device";
4242 r = -EINVAL;
4243 goto bad_common;
4244 }
4245
4246 tc->pool = __pool_table_lookup(pool_md);
4247 if (!tc->pool) {
4248 ti->error = "Couldn't find pool object";
4249 r = -EINVAL;
4250 goto bad_pool_lookup;
4251 }
4252 __pool_inc(tc->pool);
4253
4254 if (get_pool_mode(tc->pool) == PM_FAIL) {
4255 ti->error = "Couldn't open thin device, Pool is in fail mode";
4256 r = -EINVAL;
4257 goto bad_pool;
4258 }
4259
4260 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4261 if (r) {
4262 ti->error = "Couldn't open thin internal device";
4263 goto bad_pool;
4264 }
4265
4266 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4267 if (r)
4268 goto bad;
4269
4270 ti->num_flush_bios = 1;
4271 ti->limit_swap_bios = true;
4272 ti->flush_supported = true;
4273 ti->accounts_remapped_io = true;
4274 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4275
4276 /* In case the pool supports discards, pass them on. */
4277 if (tc->pool->pf.discard_enabled) {
4278 ti->discards_supported = true;
4279 ti->num_discard_bios = 1;
4280 ti->max_discard_granularity = true;
4281 }
4282
4283 mutex_unlock(&dm_thin_pool_table.mutex);
4284
4285 spin_lock_irq(&tc->pool->lock);
4286 if (tc->pool->suspended) {
4287 spin_unlock_irq(&tc->pool->lock);
4288 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
4289 ti->error = "Unable to activate thin device while pool is suspended";
4290 r = -EINVAL;
4291 goto bad;
4292 }
4293 refcount_set(&tc->refcount, 1);
4294 init_completion(&tc->can_destroy);
4295 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
4296 spin_unlock_irq(&tc->pool->lock);
4297 /*
4298 * This synchronize_rcu() call is needed here otherwise we risk a
4299 * wake_worker() call finding no bios to process (because the newly
4300 * added tc isn't yet visible). So this reduces latency since we
4301 * aren't then dependent on the periodic commit to wake_worker().
4302 */
4303 synchronize_rcu();
4304
4305 dm_put(pool_md);
4306
4307 return 0;
4308
4309bad:
4310 dm_pool_close_thin_device(tc->td);
4311bad_pool:
4312 __pool_dec(tc->pool);
4313bad_pool_lookup:
4314 dm_put(pool_md);
4315bad_common:
4316 dm_put_device(ti, tc->pool_dev);
4317bad_pool_dev:
4318 if (tc->origin_dev)
4319 dm_put_device(ti, tc->origin_dev);
4320bad_origin_dev:
4321 kfree(tc);
4322out_unlock:
4323 mutex_unlock(&dm_thin_pool_table.mutex);
4324
4325 return r;
4326}
4327
4328static int thin_map(struct dm_target *ti, struct bio *bio)
4329{
4330 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
4331
4332 return thin_bio_map(ti, bio);
4333}
4334
4335static int thin_endio(struct dm_target *ti, struct bio *bio,
4336 blk_status_t *err)
4337{
4338 unsigned long flags;
4339 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4340 struct list_head work;
4341 struct dm_thin_new_mapping *m, *tmp;
4342 struct pool *pool = h->tc->pool;
4343
4344 if (h->shared_read_entry) {
4345 INIT_LIST_HEAD(&work);
4346 dm_deferred_entry_dec(h->shared_read_entry, &work);
4347
4348 spin_lock_irqsave(&pool->lock, flags);
4349 list_for_each_entry_safe(m, tmp, &work, list) {
4350 list_del(&m->list);
4351 __complete_mapping_preparation(m);
4352 }
4353 spin_unlock_irqrestore(&pool->lock, flags);
4354 }
4355
4356 if (h->all_io_entry) {
4357 INIT_LIST_HEAD(&work);
4358 dm_deferred_entry_dec(h->all_io_entry, &work);
4359 if (!list_empty(&work)) {
4360 spin_lock_irqsave(&pool->lock, flags);
4361 list_for_each_entry_safe(m, tmp, &work, list)
4362 list_add_tail(&m->list, &pool->prepared_discards);
4363 spin_unlock_irqrestore(&pool->lock, flags);
4364 wake_worker(pool);
4365 }
4366 }
4367
4368 if (h->cell)
4369 cell_defer_no_holder(h->tc, h->cell);
4370
4371 return DM_ENDIO_DONE;
4372}
4373
4374static void thin_presuspend(struct dm_target *ti)
4375{
4376 struct thin_c *tc = ti->private;
4377
4378 if (dm_noflush_suspending(ti))
4379 noflush_work(tc, do_noflush_start);
4380}
4381
4382static void thin_postsuspend(struct dm_target *ti)
4383{
4384 struct thin_c *tc = ti->private;
4385
4386 /*
4387 * The dm_noflush_suspending flag has been cleared by now, so
4388 * unfortunately we must always run this.
4389 */
4390 noflush_work(tc, do_noflush_stop);
4391}
4392
4393static int thin_preresume(struct dm_target *ti)
4394{
4395 struct thin_c *tc = ti->private;
4396
4397 if (tc->origin_dev)
4398 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4399
4400 return 0;
4401}
4402
4403/*
4404 * <nr mapped sectors> <highest mapped sector>
4405 */
4406static void thin_status(struct dm_target *ti, status_type_t type,
4407 unsigned int status_flags, char *result, unsigned int maxlen)
4408{
4409 int r;
4410 ssize_t sz = 0;
4411 dm_block_t mapped, highest;
4412 char buf[BDEVNAME_SIZE];
4413 struct thin_c *tc = ti->private;
4414
4415 if (get_pool_mode(tc->pool) == PM_FAIL) {
4416 DMEMIT("Fail");
4417 return;
4418 }
4419
4420 if (!tc->td)
4421 DMEMIT("-");
4422 else {
4423 switch (type) {
4424 case STATUSTYPE_INFO:
4425 r = dm_thin_get_mapped_count(tc->td, &mapped);
4426 if (r) {
4427 DMERR("dm_thin_get_mapped_count returned %d", r);
4428 goto err;
4429 }
4430
4431 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4432 if (r < 0) {
4433 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4434 goto err;
4435 }
4436
4437 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4438 if (r)
4439 DMEMIT("%llu", ((highest + 1) *
4440 tc->pool->sectors_per_block) - 1);
4441 else
4442 DMEMIT("-");
4443 break;
4444
4445 case STATUSTYPE_TABLE:
4446 DMEMIT("%s %lu",
4447 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4448 (unsigned long) tc->dev_id);
4449 if (tc->origin_dev)
4450 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4451 break;
4452
4453 case STATUSTYPE_IMA:
4454 *result = '\0';
4455 break;
4456 }
4457 }
4458
4459 return;
4460
4461err:
4462 DMEMIT("Error");
4463}
4464
4465static int thin_iterate_devices(struct dm_target *ti,
4466 iterate_devices_callout_fn fn, void *data)
4467{
4468 sector_t blocks;
4469 struct thin_c *tc = ti->private;
4470 struct pool *pool = tc->pool;
4471
4472 /*
4473 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4474 * we follow a more convoluted path through to the pool's target.
4475 */
4476 if (!pool->ti)
4477 return 0; /* nothing is bound */
4478
4479 blocks = pool->ti->len;
4480 (void) sector_div(blocks, pool->sectors_per_block);
4481 if (blocks)
4482 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4483
4484 return 0;
4485}
4486
4487static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4488{
4489 struct thin_c *tc = ti->private;
4490 struct pool *pool = tc->pool;
4491
4492 if (pool->pf.discard_enabled) {
4493 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4494 limits->max_hw_discard_sectors = pool->sectors_per_block * BIO_PRISON_MAX_RANGE;
4495 }
4496}
4497
4498static struct target_type thin_target = {
4499 .name = "thin",
4500 .version = {1, 23, 0},
4501 .module = THIS_MODULE,
4502 .ctr = thin_ctr,
4503 .dtr = thin_dtr,
4504 .map = thin_map,
4505 .end_io = thin_endio,
4506 .preresume = thin_preresume,
4507 .presuspend = thin_presuspend,
4508 .postsuspend = thin_postsuspend,
4509 .status = thin_status,
4510 .iterate_devices = thin_iterate_devices,
4511 .io_hints = thin_io_hints,
4512};
4513
4514/*----------------------------------------------------------------*/
4515
4516static int __init dm_thin_init(void)
4517{
4518 int r = -ENOMEM;
4519
4520 pool_table_init();
4521
4522 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4523 if (!_new_mapping_cache)
4524 return r;
4525
4526 r = dm_register_target(&thin_target);
4527 if (r)
4528 goto bad_new_mapping_cache;
4529
4530 r = dm_register_target(&pool_target);
4531 if (r)
4532 goto bad_thin_target;
4533
4534 return 0;
4535
4536bad_thin_target:
4537 dm_unregister_target(&thin_target);
4538bad_new_mapping_cache:
4539 kmem_cache_destroy(_new_mapping_cache);
4540
4541 return r;
4542}
4543
4544static void dm_thin_exit(void)
4545{
4546 dm_unregister_target(&thin_target);
4547 dm_unregister_target(&pool_target);
4548
4549 kmem_cache_destroy(_new_mapping_cache);
4550
4551 pool_table_exit();
4552}
4553
4554module_init(dm_thin_init);
4555module_exit(dm_thin_exit);
4556
4557module_param_named(no_space_timeout, no_space_timeout_secs, uint, 0644);
4558MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4559
4560MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4561MODULE_AUTHOR("Joe Thornber <dm-devel@lists.linux.dev>");
4562MODULE_LICENSE("GPL");
1/*
2 * Copyright (C) 2011-2012 Red Hat UK.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-thin-metadata.h"
8#include "dm-bio-prison-v1.h"
9#include "dm.h"
10
11#include <linux/device-mapper.h>
12#include <linux/dm-io.h>
13#include <linux/dm-kcopyd.h>
14#include <linux/jiffies.h>
15#include <linux/log2.h>
16#include <linux/list.h>
17#include <linux/rculist.h>
18#include <linux/init.h>
19#include <linux/module.h>
20#include <linux/slab.h>
21#include <linux/vmalloc.h>
22#include <linux/sort.h>
23#include <linux/rbtree.h>
24
25#define DM_MSG_PREFIX "thin"
26
27/*
28 * Tunable constants
29 */
30#define ENDIO_HOOK_POOL_SIZE 1024
31#define MAPPING_POOL_SIZE 1024
32#define COMMIT_PERIOD HZ
33#define NO_SPACE_TIMEOUT_SECS 60
34
35static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
36
37DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
38 "A percentage of time allocated for copy on write");
39
40/*
41 * The block size of the device holding pool data must be
42 * between 64KB and 1GB.
43 */
44#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
45#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
46
47/*
48 * Device id is restricted to 24 bits.
49 */
50#define MAX_DEV_ID ((1 << 24) - 1)
51
52/*
53 * How do we handle breaking sharing of data blocks?
54 * =================================================
55 *
56 * We use a standard copy-on-write btree to store the mappings for the
57 * devices (note I'm talking about copy-on-write of the metadata here, not
58 * the data). When you take an internal snapshot you clone the root node
59 * of the origin btree. After this there is no concept of an origin or a
60 * snapshot. They are just two device trees that happen to point to the
61 * same data blocks.
62 *
63 * When we get a write in we decide if it's to a shared data block using
64 * some timestamp magic. If it is, we have to break sharing.
65 *
66 * Let's say we write to a shared block in what was the origin. The
67 * steps are:
68 *
69 * i) plug io further to this physical block. (see bio_prison code).
70 *
71 * ii) quiesce any read io to that shared data block. Obviously
72 * including all devices that share this block. (see dm_deferred_set code)
73 *
74 * iii) copy the data block to a newly allocate block. This step can be
75 * missed out if the io covers the block. (schedule_copy).
76 *
77 * iv) insert the new mapping into the origin's btree
78 * (process_prepared_mapping). This act of inserting breaks some
79 * sharing of btree nodes between the two devices. Breaking sharing only
80 * effects the btree of that specific device. Btrees for the other
81 * devices that share the block never change. The btree for the origin
82 * device as it was after the last commit is untouched, ie. we're using
83 * persistent data structures in the functional programming sense.
84 *
85 * v) unplug io to this physical block, including the io that triggered
86 * the breaking of sharing.
87 *
88 * Steps (ii) and (iii) occur in parallel.
89 *
90 * The metadata _doesn't_ need to be committed before the io continues. We
91 * get away with this because the io is always written to a _new_ block.
92 * If there's a crash, then:
93 *
94 * - The origin mapping will point to the old origin block (the shared
95 * one). This will contain the data as it was before the io that triggered
96 * the breaking of sharing came in.
97 *
98 * - The snap mapping still points to the old block. As it would after
99 * the commit.
100 *
101 * The downside of this scheme is the timestamp magic isn't perfect, and
102 * will continue to think that data block in the snapshot device is shared
103 * even after the write to the origin has broken sharing. I suspect data
104 * blocks will typically be shared by many different devices, so we're
105 * breaking sharing n + 1 times, rather than n, where n is the number of
106 * devices that reference this data block. At the moment I think the
107 * benefits far, far outweigh the disadvantages.
108 */
109
110/*----------------------------------------------------------------*/
111
112/*
113 * Key building.
114 */
115enum lock_space {
116 VIRTUAL,
117 PHYSICAL
118};
119
120static void build_key(struct dm_thin_device *td, enum lock_space ls,
121 dm_block_t b, dm_block_t e, struct dm_cell_key *key)
122{
123 key->virtual = (ls == VIRTUAL);
124 key->dev = dm_thin_dev_id(td);
125 key->block_begin = b;
126 key->block_end = e;
127}
128
129static void build_data_key(struct dm_thin_device *td, dm_block_t b,
130 struct dm_cell_key *key)
131{
132 build_key(td, PHYSICAL, b, b + 1llu, key);
133}
134
135static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
136 struct dm_cell_key *key)
137{
138 build_key(td, VIRTUAL, b, b + 1llu, key);
139}
140
141/*----------------------------------------------------------------*/
142
143#define THROTTLE_THRESHOLD (1 * HZ)
144
145struct throttle {
146 struct rw_semaphore lock;
147 unsigned long threshold;
148 bool throttle_applied;
149};
150
151static void throttle_init(struct throttle *t)
152{
153 init_rwsem(&t->lock);
154 t->throttle_applied = false;
155}
156
157static void throttle_work_start(struct throttle *t)
158{
159 t->threshold = jiffies + THROTTLE_THRESHOLD;
160}
161
162static void throttle_work_update(struct throttle *t)
163{
164 if (!t->throttle_applied && jiffies > t->threshold) {
165 down_write(&t->lock);
166 t->throttle_applied = true;
167 }
168}
169
170static void throttle_work_complete(struct throttle *t)
171{
172 if (t->throttle_applied) {
173 t->throttle_applied = false;
174 up_write(&t->lock);
175 }
176}
177
178static void throttle_lock(struct throttle *t)
179{
180 down_read(&t->lock);
181}
182
183static void throttle_unlock(struct throttle *t)
184{
185 up_read(&t->lock);
186}
187
188/*----------------------------------------------------------------*/
189
190/*
191 * A pool device ties together a metadata device and a data device. It
192 * also provides the interface for creating and destroying internal
193 * devices.
194 */
195struct dm_thin_new_mapping;
196
197/*
198 * The pool runs in 4 modes. Ordered in degraded order for comparisons.
199 */
200enum pool_mode {
201 PM_WRITE, /* metadata may be changed */
202 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
203 PM_READ_ONLY, /* metadata may not be changed */
204 PM_FAIL, /* all I/O fails */
205};
206
207struct pool_features {
208 enum pool_mode mode;
209
210 bool zero_new_blocks:1;
211 bool discard_enabled:1;
212 bool discard_passdown:1;
213 bool error_if_no_space:1;
214};
215
216struct thin_c;
217typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
218typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
219typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
220
221#define CELL_SORT_ARRAY_SIZE 8192
222
223struct pool {
224 struct list_head list;
225 struct dm_target *ti; /* Only set if a pool target is bound */
226
227 struct mapped_device *pool_md;
228 struct block_device *md_dev;
229 struct dm_pool_metadata *pmd;
230
231 dm_block_t low_water_blocks;
232 uint32_t sectors_per_block;
233 int sectors_per_block_shift;
234
235 struct pool_features pf;
236 bool low_water_triggered:1; /* A dm event has been sent */
237 bool suspended:1;
238 bool out_of_data_space:1;
239
240 struct dm_bio_prison *prison;
241 struct dm_kcopyd_client *copier;
242
243 struct workqueue_struct *wq;
244 struct throttle throttle;
245 struct work_struct worker;
246 struct delayed_work waker;
247 struct delayed_work no_space_timeout;
248
249 unsigned long last_commit_jiffies;
250 unsigned ref_count;
251
252 spinlock_t lock;
253 struct bio_list deferred_flush_bios;
254 struct list_head prepared_mappings;
255 struct list_head prepared_discards;
256 struct list_head prepared_discards_pt2;
257 struct list_head active_thins;
258
259 struct dm_deferred_set *shared_read_ds;
260 struct dm_deferred_set *all_io_ds;
261
262 struct dm_thin_new_mapping *next_mapping;
263 mempool_t *mapping_pool;
264
265 process_bio_fn process_bio;
266 process_bio_fn process_discard;
267
268 process_cell_fn process_cell;
269 process_cell_fn process_discard_cell;
270
271 process_mapping_fn process_prepared_mapping;
272 process_mapping_fn process_prepared_discard;
273 process_mapping_fn process_prepared_discard_pt2;
274
275 struct dm_bio_prison_cell **cell_sort_array;
276};
277
278static enum pool_mode get_pool_mode(struct pool *pool);
279static void metadata_operation_failed(struct pool *pool, const char *op, int r);
280
281/*
282 * Target context for a pool.
283 */
284struct pool_c {
285 struct dm_target *ti;
286 struct pool *pool;
287 struct dm_dev *data_dev;
288 struct dm_dev *metadata_dev;
289 struct dm_target_callbacks callbacks;
290
291 dm_block_t low_water_blocks;
292 struct pool_features requested_pf; /* Features requested during table load */
293 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
294};
295
296/*
297 * Target context for a thin.
298 */
299struct thin_c {
300 struct list_head list;
301 struct dm_dev *pool_dev;
302 struct dm_dev *origin_dev;
303 sector_t origin_size;
304 dm_thin_id dev_id;
305
306 struct pool *pool;
307 struct dm_thin_device *td;
308 struct mapped_device *thin_md;
309
310 bool requeue_mode:1;
311 spinlock_t lock;
312 struct list_head deferred_cells;
313 struct bio_list deferred_bio_list;
314 struct bio_list retry_on_resume_list;
315 struct rb_root sort_bio_list; /* sorted list of deferred bios */
316
317 /*
318 * Ensures the thin is not destroyed until the worker has finished
319 * iterating the active_thins list.
320 */
321 atomic_t refcount;
322 struct completion can_destroy;
323};
324
325/*----------------------------------------------------------------*/
326
327static bool block_size_is_power_of_two(struct pool *pool)
328{
329 return pool->sectors_per_block_shift >= 0;
330}
331
332static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
333{
334 return block_size_is_power_of_two(pool) ?
335 (b << pool->sectors_per_block_shift) :
336 (b * pool->sectors_per_block);
337}
338
339/*----------------------------------------------------------------*/
340
341struct discard_op {
342 struct thin_c *tc;
343 struct blk_plug plug;
344 struct bio *parent_bio;
345 struct bio *bio;
346};
347
348static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
349{
350 BUG_ON(!parent);
351
352 op->tc = tc;
353 blk_start_plug(&op->plug);
354 op->parent_bio = parent;
355 op->bio = NULL;
356}
357
358static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
359{
360 struct thin_c *tc = op->tc;
361 sector_t s = block_to_sectors(tc->pool, data_b);
362 sector_t len = block_to_sectors(tc->pool, data_e - data_b);
363
364 return __blkdev_issue_discard(tc->pool_dev->bdev, s, len,
365 GFP_NOWAIT, 0, &op->bio);
366}
367
368static void end_discard(struct discard_op *op, int r)
369{
370 if (op->bio) {
371 /*
372 * Even if one of the calls to issue_discard failed, we
373 * need to wait for the chain to complete.
374 */
375 bio_chain(op->bio, op->parent_bio);
376 bio_set_op_attrs(op->bio, REQ_OP_DISCARD, 0);
377 submit_bio(op->bio);
378 }
379
380 blk_finish_plug(&op->plug);
381
382 /*
383 * Even if r is set, there could be sub discards in flight that we
384 * need to wait for.
385 */
386 if (r && !op->parent_bio->bi_status)
387 op->parent_bio->bi_status = errno_to_blk_status(r);
388 bio_endio(op->parent_bio);
389}
390
391/*----------------------------------------------------------------*/
392
393/*
394 * wake_worker() is used when new work is queued and when pool_resume is
395 * ready to continue deferred IO processing.
396 */
397static void wake_worker(struct pool *pool)
398{
399 queue_work(pool->wq, &pool->worker);
400}
401
402/*----------------------------------------------------------------*/
403
404static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
405 struct dm_bio_prison_cell **cell_result)
406{
407 int r;
408 struct dm_bio_prison_cell *cell_prealloc;
409
410 /*
411 * Allocate a cell from the prison's mempool.
412 * This might block but it can't fail.
413 */
414 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
415
416 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
417 if (r)
418 /*
419 * We reused an old cell; we can get rid of
420 * the new one.
421 */
422 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
423
424 return r;
425}
426
427static void cell_release(struct pool *pool,
428 struct dm_bio_prison_cell *cell,
429 struct bio_list *bios)
430{
431 dm_cell_release(pool->prison, cell, bios);
432 dm_bio_prison_free_cell(pool->prison, cell);
433}
434
435static void cell_visit_release(struct pool *pool,
436 void (*fn)(void *, struct dm_bio_prison_cell *),
437 void *context,
438 struct dm_bio_prison_cell *cell)
439{
440 dm_cell_visit_release(pool->prison, fn, context, cell);
441 dm_bio_prison_free_cell(pool->prison, cell);
442}
443
444static void cell_release_no_holder(struct pool *pool,
445 struct dm_bio_prison_cell *cell,
446 struct bio_list *bios)
447{
448 dm_cell_release_no_holder(pool->prison, cell, bios);
449 dm_bio_prison_free_cell(pool->prison, cell);
450}
451
452static void cell_error_with_code(struct pool *pool,
453 struct dm_bio_prison_cell *cell, blk_status_t error_code)
454{
455 dm_cell_error(pool->prison, cell, error_code);
456 dm_bio_prison_free_cell(pool->prison, cell);
457}
458
459static blk_status_t get_pool_io_error_code(struct pool *pool)
460{
461 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
462}
463
464static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
465{
466 cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
467}
468
469static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
470{
471 cell_error_with_code(pool, cell, 0);
472}
473
474static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
475{
476 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
477}
478
479/*----------------------------------------------------------------*/
480
481/*
482 * A global list of pools that uses a struct mapped_device as a key.
483 */
484static struct dm_thin_pool_table {
485 struct mutex mutex;
486 struct list_head pools;
487} dm_thin_pool_table;
488
489static void pool_table_init(void)
490{
491 mutex_init(&dm_thin_pool_table.mutex);
492 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
493}
494
495static void pool_table_exit(void)
496{
497 mutex_destroy(&dm_thin_pool_table.mutex);
498}
499
500static void __pool_table_insert(struct pool *pool)
501{
502 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
503 list_add(&pool->list, &dm_thin_pool_table.pools);
504}
505
506static void __pool_table_remove(struct pool *pool)
507{
508 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
509 list_del(&pool->list);
510}
511
512static struct pool *__pool_table_lookup(struct mapped_device *md)
513{
514 struct pool *pool = NULL, *tmp;
515
516 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
517
518 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
519 if (tmp->pool_md == md) {
520 pool = tmp;
521 break;
522 }
523 }
524
525 return pool;
526}
527
528static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
529{
530 struct pool *pool = NULL, *tmp;
531
532 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
533
534 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
535 if (tmp->md_dev == md_dev) {
536 pool = tmp;
537 break;
538 }
539 }
540
541 return pool;
542}
543
544/*----------------------------------------------------------------*/
545
546struct dm_thin_endio_hook {
547 struct thin_c *tc;
548 struct dm_deferred_entry *shared_read_entry;
549 struct dm_deferred_entry *all_io_entry;
550 struct dm_thin_new_mapping *overwrite_mapping;
551 struct rb_node rb_node;
552 struct dm_bio_prison_cell *cell;
553};
554
555static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
556{
557 bio_list_merge(bios, master);
558 bio_list_init(master);
559}
560
561static void error_bio_list(struct bio_list *bios, blk_status_t error)
562{
563 struct bio *bio;
564
565 while ((bio = bio_list_pop(bios))) {
566 bio->bi_status = error;
567 bio_endio(bio);
568 }
569}
570
571static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
572 blk_status_t error)
573{
574 struct bio_list bios;
575 unsigned long flags;
576
577 bio_list_init(&bios);
578
579 spin_lock_irqsave(&tc->lock, flags);
580 __merge_bio_list(&bios, master);
581 spin_unlock_irqrestore(&tc->lock, flags);
582
583 error_bio_list(&bios, error);
584}
585
586static void requeue_deferred_cells(struct thin_c *tc)
587{
588 struct pool *pool = tc->pool;
589 unsigned long flags;
590 struct list_head cells;
591 struct dm_bio_prison_cell *cell, *tmp;
592
593 INIT_LIST_HEAD(&cells);
594
595 spin_lock_irqsave(&tc->lock, flags);
596 list_splice_init(&tc->deferred_cells, &cells);
597 spin_unlock_irqrestore(&tc->lock, flags);
598
599 list_for_each_entry_safe(cell, tmp, &cells, user_list)
600 cell_requeue(pool, cell);
601}
602
603static void requeue_io(struct thin_c *tc)
604{
605 struct bio_list bios;
606 unsigned long flags;
607
608 bio_list_init(&bios);
609
610 spin_lock_irqsave(&tc->lock, flags);
611 __merge_bio_list(&bios, &tc->deferred_bio_list);
612 __merge_bio_list(&bios, &tc->retry_on_resume_list);
613 spin_unlock_irqrestore(&tc->lock, flags);
614
615 error_bio_list(&bios, BLK_STS_DM_REQUEUE);
616 requeue_deferred_cells(tc);
617}
618
619static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
620{
621 struct thin_c *tc;
622
623 rcu_read_lock();
624 list_for_each_entry_rcu(tc, &pool->active_thins, list)
625 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
626 rcu_read_unlock();
627}
628
629static void error_retry_list(struct pool *pool)
630{
631 error_retry_list_with_code(pool, get_pool_io_error_code(pool));
632}
633
634/*
635 * This section of code contains the logic for processing a thin device's IO.
636 * Much of the code depends on pool object resources (lists, workqueues, etc)
637 * but most is exclusively called from the thin target rather than the thin-pool
638 * target.
639 */
640
641static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
642{
643 struct pool *pool = tc->pool;
644 sector_t block_nr = bio->bi_iter.bi_sector;
645
646 if (block_size_is_power_of_two(pool))
647 block_nr >>= pool->sectors_per_block_shift;
648 else
649 (void) sector_div(block_nr, pool->sectors_per_block);
650
651 return block_nr;
652}
653
654/*
655 * Returns the _complete_ blocks that this bio covers.
656 */
657static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
658 dm_block_t *begin, dm_block_t *end)
659{
660 struct pool *pool = tc->pool;
661 sector_t b = bio->bi_iter.bi_sector;
662 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
663
664 b += pool->sectors_per_block - 1ull; /* so we round up */
665
666 if (block_size_is_power_of_two(pool)) {
667 b >>= pool->sectors_per_block_shift;
668 e >>= pool->sectors_per_block_shift;
669 } else {
670 (void) sector_div(b, pool->sectors_per_block);
671 (void) sector_div(e, pool->sectors_per_block);
672 }
673
674 if (e < b)
675 /* Can happen if the bio is within a single block. */
676 e = b;
677
678 *begin = b;
679 *end = e;
680}
681
682static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
683{
684 struct pool *pool = tc->pool;
685 sector_t bi_sector = bio->bi_iter.bi_sector;
686
687 bio_set_dev(bio, tc->pool_dev->bdev);
688 if (block_size_is_power_of_two(pool))
689 bio->bi_iter.bi_sector =
690 (block << pool->sectors_per_block_shift) |
691 (bi_sector & (pool->sectors_per_block - 1));
692 else
693 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
694 sector_div(bi_sector, pool->sectors_per_block);
695}
696
697static void remap_to_origin(struct thin_c *tc, struct bio *bio)
698{
699 bio_set_dev(bio, tc->origin_dev->bdev);
700}
701
702static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
703{
704 return op_is_flush(bio->bi_opf) &&
705 dm_thin_changed_this_transaction(tc->td);
706}
707
708static void inc_all_io_entry(struct pool *pool, struct bio *bio)
709{
710 struct dm_thin_endio_hook *h;
711
712 if (bio_op(bio) == REQ_OP_DISCARD)
713 return;
714
715 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
716 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
717}
718
719static void issue(struct thin_c *tc, struct bio *bio)
720{
721 struct pool *pool = tc->pool;
722 unsigned long flags;
723
724 if (!bio_triggers_commit(tc, bio)) {
725 generic_make_request(bio);
726 return;
727 }
728
729 /*
730 * Complete bio with an error if earlier I/O caused changes to
731 * the metadata that can't be committed e.g, due to I/O errors
732 * on the metadata device.
733 */
734 if (dm_thin_aborted_changes(tc->td)) {
735 bio_io_error(bio);
736 return;
737 }
738
739 /*
740 * Batch together any bios that trigger commits and then issue a
741 * single commit for them in process_deferred_bios().
742 */
743 spin_lock_irqsave(&pool->lock, flags);
744 bio_list_add(&pool->deferred_flush_bios, bio);
745 spin_unlock_irqrestore(&pool->lock, flags);
746}
747
748static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
749{
750 remap_to_origin(tc, bio);
751 issue(tc, bio);
752}
753
754static void remap_and_issue(struct thin_c *tc, struct bio *bio,
755 dm_block_t block)
756{
757 remap(tc, bio, block);
758 issue(tc, bio);
759}
760
761/*----------------------------------------------------------------*/
762
763/*
764 * Bio endio functions.
765 */
766struct dm_thin_new_mapping {
767 struct list_head list;
768
769 bool pass_discard:1;
770 bool maybe_shared:1;
771
772 /*
773 * Track quiescing, copying and zeroing preparation actions. When this
774 * counter hits zero the block is prepared and can be inserted into the
775 * btree.
776 */
777 atomic_t prepare_actions;
778
779 blk_status_t status;
780 struct thin_c *tc;
781 dm_block_t virt_begin, virt_end;
782 dm_block_t data_block;
783 struct dm_bio_prison_cell *cell;
784
785 /*
786 * If the bio covers the whole area of a block then we can avoid
787 * zeroing or copying. Instead this bio is hooked. The bio will
788 * still be in the cell, so care has to be taken to avoid issuing
789 * the bio twice.
790 */
791 struct bio *bio;
792 bio_end_io_t *saved_bi_end_io;
793};
794
795static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
796{
797 struct pool *pool = m->tc->pool;
798
799 if (atomic_dec_and_test(&m->prepare_actions)) {
800 list_add_tail(&m->list, &pool->prepared_mappings);
801 wake_worker(pool);
802 }
803}
804
805static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
806{
807 unsigned long flags;
808 struct pool *pool = m->tc->pool;
809
810 spin_lock_irqsave(&pool->lock, flags);
811 __complete_mapping_preparation(m);
812 spin_unlock_irqrestore(&pool->lock, flags);
813}
814
815static void copy_complete(int read_err, unsigned long write_err, void *context)
816{
817 struct dm_thin_new_mapping *m = context;
818
819 m->status = read_err || write_err ? BLK_STS_IOERR : 0;
820 complete_mapping_preparation(m);
821}
822
823static void overwrite_endio(struct bio *bio)
824{
825 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
826 struct dm_thin_new_mapping *m = h->overwrite_mapping;
827
828 bio->bi_end_io = m->saved_bi_end_io;
829
830 m->status = bio->bi_status;
831 complete_mapping_preparation(m);
832}
833
834/*----------------------------------------------------------------*/
835
836/*
837 * Workqueue.
838 */
839
840/*
841 * Prepared mapping jobs.
842 */
843
844/*
845 * This sends the bios in the cell, except the original holder, back
846 * to the deferred_bios list.
847 */
848static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
849{
850 struct pool *pool = tc->pool;
851 unsigned long flags;
852
853 spin_lock_irqsave(&tc->lock, flags);
854 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
855 spin_unlock_irqrestore(&tc->lock, flags);
856
857 wake_worker(pool);
858}
859
860static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
861
862struct remap_info {
863 struct thin_c *tc;
864 struct bio_list defer_bios;
865 struct bio_list issue_bios;
866};
867
868static void __inc_remap_and_issue_cell(void *context,
869 struct dm_bio_prison_cell *cell)
870{
871 struct remap_info *info = context;
872 struct bio *bio;
873
874 while ((bio = bio_list_pop(&cell->bios))) {
875 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
876 bio_list_add(&info->defer_bios, bio);
877 else {
878 inc_all_io_entry(info->tc->pool, bio);
879
880 /*
881 * We can't issue the bios with the bio prison lock
882 * held, so we add them to a list to issue on
883 * return from this function.
884 */
885 bio_list_add(&info->issue_bios, bio);
886 }
887 }
888}
889
890static void inc_remap_and_issue_cell(struct thin_c *tc,
891 struct dm_bio_prison_cell *cell,
892 dm_block_t block)
893{
894 struct bio *bio;
895 struct remap_info info;
896
897 info.tc = tc;
898 bio_list_init(&info.defer_bios);
899 bio_list_init(&info.issue_bios);
900
901 /*
902 * We have to be careful to inc any bios we're about to issue
903 * before the cell is released, and avoid a race with new bios
904 * being added to the cell.
905 */
906 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
907 &info, cell);
908
909 while ((bio = bio_list_pop(&info.defer_bios)))
910 thin_defer_bio(tc, bio);
911
912 while ((bio = bio_list_pop(&info.issue_bios)))
913 remap_and_issue(info.tc, bio, block);
914}
915
916static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
917{
918 cell_error(m->tc->pool, m->cell);
919 list_del(&m->list);
920 mempool_free(m, m->tc->pool->mapping_pool);
921}
922
923static void process_prepared_mapping(struct dm_thin_new_mapping *m)
924{
925 struct thin_c *tc = m->tc;
926 struct pool *pool = tc->pool;
927 struct bio *bio = m->bio;
928 int r;
929
930 if (m->status) {
931 cell_error(pool, m->cell);
932 goto out;
933 }
934
935 /*
936 * Commit the prepared block into the mapping btree.
937 * Any I/O for this block arriving after this point will get
938 * remapped to it directly.
939 */
940 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
941 if (r) {
942 metadata_operation_failed(pool, "dm_thin_insert_block", r);
943 cell_error(pool, m->cell);
944 goto out;
945 }
946
947 /*
948 * Release any bios held while the block was being provisioned.
949 * If we are processing a write bio that completely covers the block,
950 * we already processed it so can ignore it now when processing
951 * the bios in the cell.
952 */
953 if (bio) {
954 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
955 bio_endio(bio);
956 } else {
957 inc_all_io_entry(tc->pool, m->cell->holder);
958 remap_and_issue(tc, m->cell->holder, m->data_block);
959 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
960 }
961
962out:
963 list_del(&m->list);
964 mempool_free(m, pool->mapping_pool);
965}
966
967/*----------------------------------------------------------------*/
968
969static void free_discard_mapping(struct dm_thin_new_mapping *m)
970{
971 struct thin_c *tc = m->tc;
972 if (m->cell)
973 cell_defer_no_holder(tc, m->cell);
974 mempool_free(m, tc->pool->mapping_pool);
975}
976
977static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
978{
979 bio_io_error(m->bio);
980 free_discard_mapping(m);
981}
982
983static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
984{
985 bio_endio(m->bio);
986 free_discard_mapping(m);
987}
988
989static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
990{
991 int r;
992 struct thin_c *tc = m->tc;
993
994 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
995 if (r) {
996 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
997 bio_io_error(m->bio);
998 } else
999 bio_endio(m->bio);
1000
1001 cell_defer_no_holder(tc, m->cell);
1002 mempool_free(m, tc->pool->mapping_pool);
1003}
1004
1005/*----------------------------------------------------------------*/
1006
1007static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
1008 struct bio *discard_parent)
1009{
1010 /*
1011 * We've already unmapped this range of blocks, but before we
1012 * passdown we have to check that these blocks are now unused.
1013 */
1014 int r = 0;
1015 bool used = true;
1016 struct thin_c *tc = m->tc;
1017 struct pool *pool = tc->pool;
1018 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
1019 struct discard_op op;
1020
1021 begin_discard(&op, tc, discard_parent);
1022 while (b != end) {
1023 /* find start of unmapped run */
1024 for (; b < end; b++) {
1025 r = dm_pool_block_is_used(pool->pmd, b, &used);
1026 if (r)
1027 goto out;
1028
1029 if (!used)
1030 break;
1031 }
1032
1033 if (b == end)
1034 break;
1035
1036 /* find end of run */
1037 for (e = b + 1; e != end; e++) {
1038 r = dm_pool_block_is_used(pool->pmd, e, &used);
1039 if (r)
1040 goto out;
1041
1042 if (used)
1043 break;
1044 }
1045
1046 r = issue_discard(&op, b, e);
1047 if (r)
1048 goto out;
1049
1050 b = e;
1051 }
1052out:
1053 end_discard(&op, r);
1054}
1055
1056static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
1057{
1058 unsigned long flags;
1059 struct pool *pool = m->tc->pool;
1060
1061 spin_lock_irqsave(&pool->lock, flags);
1062 list_add_tail(&m->list, &pool->prepared_discards_pt2);
1063 spin_unlock_irqrestore(&pool->lock, flags);
1064 wake_worker(pool);
1065}
1066
1067static void passdown_endio(struct bio *bio)
1068{
1069 /*
1070 * It doesn't matter if the passdown discard failed, we still want
1071 * to unmap (we ignore err).
1072 */
1073 queue_passdown_pt2(bio->bi_private);
1074 bio_put(bio);
1075}
1076
1077static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
1078{
1079 int r;
1080 struct thin_c *tc = m->tc;
1081 struct pool *pool = tc->pool;
1082 struct bio *discard_parent;
1083 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
1084
1085 /*
1086 * Only this thread allocates blocks, so we can be sure that the
1087 * newly unmapped blocks will not be allocated before the end of
1088 * the function.
1089 */
1090 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
1091 if (r) {
1092 metadata_operation_failed(pool, "dm_thin_remove_range", r);
1093 bio_io_error(m->bio);
1094 cell_defer_no_holder(tc, m->cell);
1095 mempool_free(m, pool->mapping_pool);
1096 return;
1097 }
1098
1099 /*
1100 * Increment the unmapped blocks. This prevents a race between the
1101 * passdown io and reallocation of freed blocks.
1102 */
1103 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
1104 if (r) {
1105 metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
1106 bio_io_error(m->bio);
1107 cell_defer_no_holder(tc, m->cell);
1108 mempool_free(m, pool->mapping_pool);
1109 return;
1110 }
1111
1112 discard_parent = bio_alloc(GFP_NOIO, 1);
1113 if (!discard_parent) {
1114 DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.",
1115 dm_device_name(tc->pool->pool_md));
1116 queue_passdown_pt2(m);
1117
1118 } else {
1119 discard_parent->bi_end_io = passdown_endio;
1120 discard_parent->bi_private = m;
1121
1122 if (m->maybe_shared)
1123 passdown_double_checking_shared_status(m, discard_parent);
1124 else {
1125 struct discard_op op;
1126
1127 begin_discard(&op, tc, discard_parent);
1128 r = issue_discard(&op, m->data_block, data_end);
1129 end_discard(&op, r);
1130 }
1131 }
1132}
1133
1134static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1135{
1136 int r;
1137 struct thin_c *tc = m->tc;
1138 struct pool *pool = tc->pool;
1139
1140 /*
1141 * The passdown has completed, so now we can decrement all those
1142 * unmapped blocks.
1143 */
1144 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1145 m->data_block + (m->virt_end - m->virt_begin));
1146 if (r) {
1147 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1148 bio_io_error(m->bio);
1149 } else
1150 bio_endio(m->bio);
1151
1152 cell_defer_no_holder(tc, m->cell);
1153 mempool_free(m, pool->mapping_pool);
1154}
1155
1156static void process_prepared(struct pool *pool, struct list_head *head,
1157 process_mapping_fn *fn)
1158{
1159 unsigned long flags;
1160 struct list_head maps;
1161 struct dm_thin_new_mapping *m, *tmp;
1162
1163 INIT_LIST_HEAD(&maps);
1164 spin_lock_irqsave(&pool->lock, flags);
1165 list_splice_init(head, &maps);
1166 spin_unlock_irqrestore(&pool->lock, flags);
1167
1168 list_for_each_entry_safe(m, tmp, &maps, list)
1169 (*fn)(m);
1170}
1171
1172/*
1173 * Deferred bio jobs.
1174 */
1175static int io_overlaps_block(struct pool *pool, struct bio *bio)
1176{
1177 return bio->bi_iter.bi_size ==
1178 (pool->sectors_per_block << SECTOR_SHIFT);
1179}
1180
1181static int io_overwrites_block(struct pool *pool, struct bio *bio)
1182{
1183 return (bio_data_dir(bio) == WRITE) &&
1184 io_overlaps_block(pool, bio);
1185}
1186
1187static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1188 bio_end_io_t *fn)
1189{
1190 *save = bio->bi_end_io;
1191 bio->bi_end_io = fn;
1192}
1193
1194static int ensure_next_mapping(struct pool *pool)
1195{
1196 if (pool->next_mapping)
1197 return 0;
1198
1199 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
1200
1201 return pool->next_mapping ? 0 : -ENOMEM;
1202}
1203
1204static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1205{
1206 struct dm_thin_new_mapping *m = pool->next_mapping;
1207
1208 BUG_ON(!pool->next_mapping);
1209
1210 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1211 INIT_LIST_HEAD(&m->list);
1212 m->bio = NULL;
1213
1214 pool->next_mapping = NULL;
1215
1216 return m;
1217}
1218
1219static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1220 sector_t begin, sector_t end)
1221{
1222 int r;
1223 struct dm_io_region to;
1224
1225 to.bdev = tc->pool_dev->bdev;
1226 to.sector = begin;
1227 to.count = end - begin;
1228
1229 r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1230 if (r < 0) {
1231 DMERR_LIMIT("dm_kcopyd_zero() failed");
1232 copy_complete(1, 1, m);
1233 }
1234}
1235
1236static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1237 dm_block_t data_begin,
1238 struct dm_thin_new_mapping *m)
1239{
1240 struct pool *pool = tc->pool;
1241 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1242
1243 h->overwrite_mapping = m;
1244 m->bio = bio;
1245 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1246 inc_all_io_entry(pool, bio);
1247 remap_and_issue(tc, bio, data_begin);
1248}
1249
1250/*
1251 * A partial copy also needs to zero the uncopied region.
1252 */
1253static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1254 struct dm_dev *origin, dm_block_t data_origin,
1255 dm_block_t data_dest,
1256 struct dm_bio_prison_cell *cell, struct bio *bio,
1257 sector_t len)
1258{
1259 int r;
1260 struct pool *pool = tc->pool;
1261 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1262
1263 m->tc = tc;
1264 m->virt_begin = virt_block;
1265 m->virt_end = virt_block + 1u;
1266 m->data_block = data_dest;
1267 m->cell = cell;
1268
1269 /*
1270 * quiesce action + copy action + an extra reference held for the
1271 * duration of this function (we may need to inc later for a
1272 * partial zero).
1273 */
1274 atomic_set(&m->prepare_actions, 3);
1275
1276 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1277 complete_mapping_preparation(m); /* already quiesced */
1278
1279 /*
1280 * IO to pool_dev remaps to the pool target's data_dev.
1281 *
1282 * If the whole block of data is being overwritten, we can issue the
1283 * bio immediately. Otherwise we use kcopyd to clone the data first.
1284 */
1285 if (io_overwrites_block(pool, bio))
1286 remap_and_issue_overwrite(tc, bio, data_dest, m);
1287 else {
1288 struct dm_io_region from, to;
1289
1290 from.bdev = origin->bdev;
1291 from.sector = data_origin * pool->sectors_per_block;
1292 from.count = len;
1293
1294 to.bdev = tc->pool_dev->bdev;
1295 to.sector = data_dest * pool->sectors_per_block;
1296 to.count = len;
1297
1298 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
1299 0, copy_complete, m);
1300 if (r < 0) {
1301 DMERR_LIMIT("dm_kcopyd_copy() failed");
1302 copy_complete(1, 1, m);
1303
1304 /*
1305 * We allow the zero to be issued, to simplify the
1306 * error path. Otherwise we'd need to start
1307 * worrying about decrementing the prepare_actions
1308 * counter.
1309 */
1310 }
1311
1312 /*
1313 * Do we need to zero a tail region?
1314 */
1315 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1316 atomic_inc(&m->prepare_actions);
1317 ll_zero(tc, m,
1318 data_dest * pool->sectors_per_block + len,
1319 (data_dest + 1) * pool->sectors_per_block);
1320 }
1321 }
1322
1323 complete_mapping_preparation(m); /* drop our ref */
1324}
1325
1326static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1327 dm_block_t data_origin, dm_block_t data_dest,
1328 struct dm_bio_prison_cell *cell, struct bio *bio)
1329{
1330 schedule_copy(tc, virt_block, tc->pool_dev,
1331 data_origin, data_dest, cell, bio,
1332 tc->pool->sectors_per_block);
1333}
1334
1335static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1336 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1337 struct bio *bio)
1338{
1339 struct pool *pool = tc->pool;
1340 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1341
1342 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1343 m->tc = tc;
1344 m->virt_begin = virt_block;
1345 m->virt_end = virt_block + 1u;
1346 m->data_block = data_block;
1347 m->cell = cell;
1348
1349 /*
1350 * If the whole block of data is being overwritten or we are not
1351 * zeroing pre-existing data, we can issue the bio immediately.
1352 * Otherwise we use kcopyd to zero the data first.
1353 */
1354 if (pool->pf.zero_new_blocks) {
1355 if (io_overwrites_block(pool, bio))
1356 remap_and_issue_overwrite(tc, bio, data_block, m);
1357 else
1358 ll_zero(tc, m, data_block * pool->sectors_per_block,
1359 (data_block + 1) * pool->sectors_per_block);
1360 } else
1361 process_prepared_mapping(m);
1362}
1363
1364static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1365 dm_block_t data_dest,
1366 struct dm_bio_prison_cell *cell, struct bio *bio)
1367{
1368 struct pool *pool = tc->pool;
1369 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1370 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1371
1372 if (virt_block_end <= tc->origin_size)
1373 schedule_copy(tc, virt_block, tc->origin_dev,
1374 virt_block, data_dest, cell, bio,
1375 pool->sectors_per_block);
1376
1377 else if (virt_block_begin < tc->origin_size)
1378 schedule_copy(tc, virt_block, tc->origin_dev,
1379 virt_block, data_dest, cell, bio,
1380 tc->origin_size - virt_block_begin);
1381
1382 else
1383 schedule_zero(tc, virt_block, data_dest, cell, bio);
1384}
1385
1386static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1387
1388static void check_for_space(struct pool *pool)
1389{
1390 int r;
1391 dm_block_t nr_free;
1392
1393 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1394 return;
1395
1396 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1397 if (r)
1398 return;
1399
1400 if (nr_free)
1401 set_pool_mode(pool, PM_WRITE);
1402}
1403
1404/*
1405 * A non-zero return indicates read_only or fail_io mode.
1406 * Many callers don't care about the return value.
1407 */
1408static int commit(struct pool *pool)
1409{
1410 int r;
1411
1412 if (get_pool_mode(pool) >= PM_READ_ONLY)
1413 return -EINVAL;
1414
1415 r = dm_pool_commit_metadata(pool->pmd);
1416 if (r)
1417 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1418 else
1419 check_for_space(pool);
1420
1421 return r;
1422}
1423
1424static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1425{
1426 unsigned long flags;
1427
1428 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1429 DMWARN("%s: reached low water mark for data device: sending event.",
1430 dm_device_name(pool->pool_md));
1431 spin_lock_irqsave(&pool->lock, flags);
1432 pool->low_water_triggered = true;
1433 spin_unlock_irqrestore(&pool->lock, flags);
1434 dm_table_event(pool->ti->table);
1435 }
1436}
1437
1438static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1439{
1440 int r;
1441 dm_block_t free_blocks;
1442 struct pool *pool = tc->pool;
1443
1444 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1445 return -EINVAL;
1446
1447 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1448 if (r) {
1449 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1450 return r;
1451 }
1452
1453 check_low_water_mark(pool, free_blocks);
1454
1455 if (!free_blocks) {
1456 /*
1457 * Try to commit to see if that will free up some
1458 * more space.
1459 */
1460 r = commit(pool);
1461 if (r)
1462 return r;
1463
1464 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1465 if (r) {
1466 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1467 return r;
1468 }
1469
1470 if (!free_blocks) {
1471 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1472 return -ENOSPC;
1473 }
1474 }
1475
1476 r = dm_pool_alloc_data_block(pool->pmd, result);
1477 if (r) {
1478 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1479 return r;
1480 }
1481
1482 return 0;
1483}
1484
1485/*
1486 * If we have run out of space, queue bios until the device is
1487 * resumed, presumably after having been reloaded with more space.
1488 */
1489static void retry_on_resume(struct bio *bio)
1490{
1491 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1492 struct thin_c *tc = h->tc;
1493 unsigned long flags;
1494
1495 spin_lock_irqsave(&tc->lock, flags);
1496 bio_list_add(&tc->retry_on_resume_list, bio);
1497 spin_unlock_irqrestore(&tc->lock, flags);
1498}
1499
1500static blk_status_t should_error_unserviceable_bio(struct pool *pool)
1501{
1502 enum pool_mode m = get_pool_mode(pool);
1503
1504 switch (m) {
1505 case PM_WRITE:
1506 /* Shouldn't get here */
1507 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1508 return BLK_STS_IOERR;
1509
1510 case PM_OUT_OF_DATA_SPACE:
1511 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
1512
1513 case PM_READ_ONLY:
1514 case PM_FAIL:
1515 return BLK_STS_IOERR;
1516 default:
1517 /* Shouldn't get here */
1518 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1519 return BLK_STS_IOERR;
1520 }
1521}
1522
1523static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1524{
1525 blk_status_t error = should_error_unserviceable_bio(pool);
1526
1527 if (error) {
1528 bio->bi_status = error;
1529 bio_endio(bio);
1530 } else
1531 retry_on_resume(bio);
1532}
1533
1534static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1535{
1536 struct bio *bio;
1537 struct bio_list bios;
1538 blk_status_t error;
1539
1540 error = should_error_unserviceable_bio(pool);
1541 if (error) {
1542 cell_error_with_code(pool, cell, error);
1543 return;
1544 }
1545
1546 bio_list_init(&bios);
1547 cell_release(pool, cell, &bios);
1548
1549 while ((bio = bio_list_pop(&bios)))
1550 retry_on_resume(bio);
1551}
1552
1553static void process_discard_cell_no_passdown(struct thin_c *tc,
1554 struct dm_bio_prison_cell *virt_cell)
1555{
1556 struct pool *pool = tc->pool;
1557 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1558
1559 /*
1560 * We don't need to lock the data blocks, since there's no
1561 * passdown. We only lock data blocks for allocation and breaking sharing.
1562 */
1563 m->tc = tc;
1564 m->virt_begin = virt_cell->key.block_begin;
1565 m->virt_end = virt_cell->key.block_end;
1566 m->cell = virt_cell;
1567 m->bio = virt_cell->holder;
1568
1569 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1570 pool->process_prepared_discard(m);
1571}
1572
1573static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1574 struct bio *bio)
1575{
1576 struct pool *pool = tc->pool;
1577
1578 int r;
1579 bool maybe_shared;
1580 struct dm_cell_key data_key;
1581 struct dm_bio_prison_cell *data_cell;
1582 struct dm_thin_new_mapping *m;
1583 dm_block_t virt_begin, virt_end, data_begin;
1584
1585 while (begin != end) {
1586 r = ensure_next_mapping(pool);
1587 if (r)
1588 /* we did our best */
1589 return;
1590
1591 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1592 &data_begin, &maybe_shared);
1593 if (r)
1594 /*
1595 * Silently fail, letting any mappings we've
1596 * created complete.
1597 */
1598 break;
1599
1600 build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key);
1601 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1602 /* contention, we'll give up with this range */
1603 begin = virt_end;
1604 continue;
1605 }
1606
1607 /*
1608 * IO may still be going to the destination block. We must
1609 * quiesce before we can do the removal.
1610 */
1611 m = get_next_mapping(pool);
1612 m->tc = tc;
1613 m->maybe_shared = maybe_shared;
1614 m->virt_begin = virt_begin;
1615 m->virt_end = virt_end;
1616 m->data_block = data_begin;
1617 m->cell = data_cell;
1618 m->bio = bio;
1619
1620 /*
1621 * The parent bio must not complete before sub discard bios are
1622 * chained to it (see end_discard's bio_chain)!
1623 *
1624 * This per-mapping bi_remaining increment is paired with
1625 * the implicit decrement that occurs via bio_endio() in
1626 * end_discard().
1627 */
1628 bio_inc_remaining(bio);
1629 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1630 pool->process_prepared_discard(m);
1631
1632 begin = virt_end;
1633 }
1634}
1635
1636static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1637{
1638 struct bio *bio = virt_cell->holder;
1639 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1640
1641 /*
1642 * The virt_cell will only get freed once the origin bio completes.
1643 * This means it will remain locked while all the individual
1644 * passdown bios are in flight.
1645 */
1646 h->cell = virt_cell;
1647 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1648
1649 /*
1650 * We complete the bio now, knowing that the bi_remaining field
1651 * will prevent completion until the sub range discards have
1652 * completed.
1653 */
1654 bio_endio(bio);
1655}
1656
1657static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1658{
1659 dm_block_t begin, end;
1660 struct dm_cell_key virt_key;
1661 struct dm_bio_prison_cell *virt_cell;
1662
1663 get_bio_block_range(tc, bio, &begin, &end);
1664 if (begin == end) {
1665 /*
1666 * The discard covers less than a block.
1667 */
1668 bio_endio(bio);
1669 return;
1670 }
1671
1672 build_key(tc->td, VIRTUAL, begin, end, &virt_key);
1673 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell))
1674 /*
1675 * Potential starvation issue: We're relying on the
1676 * fs/application being well behaved, and not trying to
1677 * send IO to a region at the same time as discarding it.
1678 * If they do this persistently then it's possible this
1679 * cell will never be granted.
1680 */
1681 return;
1682
1683 tc->pool->process_discard_cell(tc, virt_cell);
1684}
1685
1686static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1687 struct dm_cell_key *key,
1688 struct dm_thin_lookup_result *lookup_result,
1689 struct dm_bio_prison_cell *cell)
1690{
1691 int r;
1692 dm_block_t data_block;
1693 struct pool *pool = tc->pool;
1694
1695 r = alloc_data_block(tc, &data_block);
1696 switch (r) {
1697 case 0:
1698 schedule_internal_copy(tc, block, lookup_result->block,
1699 data_block, cell, bio);
1700 break;
1701
1702 case -ENOSPC:
1703 retry_bios_on_resume(pool, cell);
1704 break;
1705
1706 default:
1707 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1708 __func__, r);
1709 cell_error(pool, cell);
1710 break;
1711 }
1712}
1713
1714static void __remap_and_issue_shared_cell(void *context,
1715 struct dm_bio_prison_cell *cell)
1716{
1717 struct remap_info *info = context;
1718 struct bio *bio;
1719
1720 while ((bio = bio_list_pop(&cell->bios))) {
1721 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
1722 bio_op(bio) == REQ_OP_DISCARD)
1723 bio_list_add(&info->defer_bios, bio);
1724 else {
1725 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1726
1727 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1728 inc_all_io_entry(info->tc->pool, bio);
1729 bio_list_add(&info->issue_bios, bio);
1730 }
1731 }
1732}
1733
1734static void remap_and_issue_shared_cell(struct thin_c *tc,
1735 struct dm_bio_prison_cell *cell,
1736 dm_block_t block)
1737{
1738 struct bio *bio;
1739 struct remap_info info;
1740
1741 info.tc = tc;
1742 bio_list_init(&info.defer_bios);
1743 bio_list_init(&info.issue_bios);
1744
1745 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1746 &info, cell);
1747
1748 while ((bio = bio_list_pop(&info.defer_bios)))
1749 thin_defer_bio(tc, bio);
1750
1751 while ((bio = bio_list_pop(&info.issue_bios)))
1752 remap_and_issue(tc, bio, block);
1753}
1754
1755static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1756 dm_block_t block,
1757 struct dm_thin_lookup_result *lookup_result,
1758 struct dm_bio_prison_cell *virt_cell)
1759{
1760 struct dm_bio_prison_cell *data_cell;
1761 struct pool *pool = tc->pool;
1762 struct dm_cell_key key;
1763
1764 /*
1765 * If cell is already occupied, then sharing is already in the process
1766 * of being broken so we have nothing further to do here.
1767 */
1768 build_data_key(tc->td, lookup_result->block, &key);
1769 if (bio_detain(pool, &key, bio, &data_cell)) {
1770 cell_defer_no_holder(tc, virt_cell);
1771 return;
1772 }
1773
1774 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1775 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1776 cell_defer_no_holder(tc, virt_cell);
1777 } else {
1778 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1779
1780 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1781 inc_all_io_entry(pool, bio);
1782 remap_and_issue(tc, bio, lookup_result->block);
1783
1784 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1785 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1786 }
1787}
1788
1789static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1790 struct dm_bio_prison_cell *cell)
1791{
1792 int r;
1793 dm_block_t data_block;
1794 struct pool *pool = tc->pool;
1795
1796 /*
1797 * Remap empty bios (flushes) immediately, without provisioning.
1798 */
1799 if (!bio->bi_iter.bi_size) {
1800 inc_all_io_entry(pool, bio);
1801 cell_defer_no_holder(tc, cell);
1802
1803 remap_and_issue(tc, bio, 0);
1804 return;
1805 }
1806
1807 /*
1808 * Fill read bios with zeroes and complete them immediately.
1809 */
1810 if (bio_data_dir(bio) == READ) {
1811 zero_fill_bio(bio);
1812 cell_defer_no_holder(tc, cell);
1813 bio_endio(bio);
1814 return;
1815 }
1816
1817 r = alloc_data_block(tc, &data_block);
1818 switch (r) {
1819 case 0:
1820 if (tc->origin_dev)
1821 schedule_external_copy(tc, block, data_block, cell, bio);
1822 else
1823 schedule_zero(tc, block, data_block, cell, bio);
1824 break;
1825
1826 case -ENOSPC:
1827 retry_bios_on_resume(pool, cell);
1828 break;
1829
1830 default:
1831 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1832 __func__, r);
1833 cell_error(pool, cell);
1834 break;
1835 }
1836}
1837
1838static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1839{
1840 int r;
1841 struct pool *pool = tc->pool;
1842 struct bio *bio = cell->holder;
1843 dm_block_t block = get_bio_block(tc, bio);
1844 struct dm_thin_lookup_result lookup_result;
1845
1846 if (tc->requeue_mode) {
1847 cell_requeue(pool, cell);
1848 return;
1849 }
1850
1851 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1852 switch (r) {
1853 case 0:
1854 if (lookup_result.shared)
1855 process_shared_bio(tc, bio, block, &lookup_result, cell);
1856 else {
1857 inc_all_io_entry(pool, bio);
1858 remap_and_issue(tc, bio, lookup_result.block);
1859 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1860 }
1861 break;
1862
1863 case -ENODATA:
1864 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1865 inc_all_io_entry(pool, bio);
1866 cell_defer_no_holder(tc, cell);
1867
1868 if (bio_end_sector(bio) <= tc->origin_size)
1869 remap_to_origin_and_issue(tc, bio);
1870
1871 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1872 zero_fill_bio(bio);
1873 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1874 remap_to_origin_and_issue(tc, bio);
1875
1876 } else {
1877 zero_fill_bio(bio);
1878 bio_endio(bio);
1879 }
1880 } else
1881 provision_block(tc, bio, block, cell);
1882 break;
1883
1884 default:
1885 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1886 __func__, r);
1887 cell_defer_no_holder(tc, cell);
1888 bio_io_error(bio);
1889 break;
1890 }
1891}
1892
1893static void process_bio(struct thin_c *tc, struct bio *bio)
1894{
1895 struct pool *pool = tc->pool;
1896 dm_block_t block = get_bio_block(tc, bio);
1897 struct dm_bio_prison_cell *cell;
1898 struct dm_cell_key key;
1899
1900 /*
1901 * If cell is already occupied, then the block is already
1902 * being provisioned so we have nothing further to do here.
1903 */
1904 build_virtual_key(tc->td, block, &key);
1905 if (bio_detain(pool, &key, bio, &cell))
1906 return;
1907
1908 process_cell(tc, cell);
1909}
1910
1911static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
1912 struct dm_bio_prison_cell *cell)
1913{
1914 int r;
1915 int rw = bio_data_dir(bio);
1916 dm_block_t block = get_bio_block(tc, bio);
1917 struct dm_thin_lookup_result lookup_result;
1918
1919 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1920 switch (r) {
1921 case 0:
1922 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
1923 handle_unserviceable_bio(tc->pool, bio);
1924 if (cell)
1925 cell_defer_no_holder(tc, cell);
1926 } else {
1927 inc_all_io_entry(tc->pool, bio);
1928 remap_and_issue(tc, bio, lookup_result.block);
1929 if (cell)
1930 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1931 }
1932 break;
1933
1934 case -ENODATA:
1935 if (cell)
1936 cell_defer_no_holder(tc, cell);
1937 if (rw != READ) {
1938 handle_unserviceable_bio(tc->pool, bio);
1939 break;
1940 }
1941
1942 if (tc->origin_dev) {
1943 inc_all_io_entry(tc->pool, bio);
1944 remap_to_origin_and_issue(tc, bio);
1945 break;
1946 }
1947
1948 zero_fill_bio(bio);
1949 bio_endio(bio);
1950 break;
1951
1952 default:
1953 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1954 __func__, r);
1955 if (cell)
1956 cell_defer_no_holder(tc, cell);
1957 bio_io_error(bio);
1958 break;
1959 }
1960}
1961
1962static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1963{
1964 __process_bio_read_only(tc, bio, NULL);
1965}
1966
1967static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1968{
1969 __process_bio_read_only(tc, cell->holder, cell);
1970}
1971
1972static void process_bio_success(struct thin_c *tc, struct bio *bio)
1973{
1974 bio_endio(bio);
1975}
1976
1977static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1978{
1979 bio_io_error(bio);
1980}
1981
1982static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1983{
1984 cell_success(tc->pool, cell);
1985}
1986
1987static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1988{
1989 cell_error(tc->pool, cell);
1990}
1991
1992/*
1993 * FIXME: should we also commit due to size of transaction, measured in
1994 * metadata blocks?
1995 */
1996static int need_commit_due_to_time(struct pool *pool)
1997{
1998 return !time_in_range(jiffies, pool->last_commit_jiffies,
1999 pool->last_commit_jiffies + COMMIT_PERIOD);
2000}
2001
2002#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2003#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2004
2005static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2006{
2007 struct rb_node **rbp, *parent;
2008 struct dm_thin_endio_hook *pbd;
2009 sector_t bi_sector = bio->bi_iter.bi_sector;
2010
2011 rbp = &tc->sort_bio_list.rb_node;
2012 parent = NULL;
2013 while (*rbp) {
2014 parent = *rbp;
2015 pbd = thin_pbd(parent);
2016
2017 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2018 rbp = &(*rbp)->rb_left;
2019 else
2020 rbp = &(*rbp)->rb_right;
2021 }
2022
2023 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2024 rb_link_node(&pbd->rb_node, parent, rbp);
2025 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2026}
2027
2028static void __extract_sorted_bios(struct thin_c *tc)
2029{
2030 struct rb_node *node;
2031 struct dm_thin_endio_hook *pbd;
2032 struct bio *bio;
2033
2034 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2035 pbd = thin_pbd(node);
2036 bio = thin_bio(pbd);
2037
2038 bio_list_add(&tc->deferred_bio_list, bio);
2039 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2040 }
2041
2042 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2043}
2044
2045static void __sort_thin_deferred_bios(struct thin_c *tc)
2046{
2047 struct bio *bio;
2048 struct bio_list bios;
2049
2050 bio_list_init(&bios);
2051 bio_list_merge(&bios, &tc->deferred_bio_list);
2052 bio_list_init(&tc->deferred_bio_list);
2053
2054 /* Sort deferred_bio_list using rb-tree */
2055 while ((bio = bio_list_pop(&bios)))
2056 __thin_bio_rb_add(tc, bio);
2057
2058 /*
2059 * Transfer the sorted bios in sort_bio_list back to
2060 * deferred_bio_list to allow lockless submission of
2061 * all bios.
2062 */
2063 __extract_sorted_bios(tc);
2064}
2065
2066static void process_thin_deferred_bios(struct thin_c *tc)
2067{
2068 struct pool *pool = tc->pool;
2069 unsigned long flags;
2070 struct bio *bio;
2071 struct bio_list bios;
2072 struct blk_plug plug;
2073 unsigned count = 0;
2074
2075 if (tc->requeue_mode) {
2076 error_thin_bio_list(tc, &tc->deferred_bio_list,
2077 BLK_STS_DM_REQUEUE);
2078 return;
2079 }
2080
2081 bio_list_init(&bios);
2082
2083 spin_lock_irqsave(&tc->lock, flags);
2084
2085 if (bio_list_empty(&tc->deferred_bio_list)) {
2086 spin_unlock_irqrestore(&tc->lock, flags);
2087 return;
2088 }
2089
2090 __sort_thin_deferred_bios(tc);
2091
2092 bio_list_merge(&bios, &tc->deferred_bio_list);
2093 bio_list_init(&tc->deferred_bio_list);
2094
2095 spin_unlock_irqrestore(&tc->lock, flags);
2096
2097 blk_start_plug(&plug);
2098 while ((bio = bio_list_pop(&bios))) {
2099 /*
2100 * If we've got no free new_mapping structs, and processing
2101 * this bio might require one, we pause until there are some
2102 * prepared mappings to process.
2103 */
2104 if (ensure_next_mapping(pool)) {
2105 spin_lock_irqsave(&tc->lock, flags);
2106 bio_list_add(&tc->deferred_bio_list, bio);
2107 bio_list_merge(&tc->deferred_bio_list, &bios);
2108 spin_unlock_irqrestore(&tc->lock, flags);
2109 break;
2110 }
2111
2112 if (bio_op(bio) == REQ_OP_DISCARD)
2113 pool->process_discard(tc, bio);
2114 else
2115 pool->process_bio(tc, bio);
2116
2117 if ((count++ & 127) == 0) {
2118 throttle_work_update(&pool->throttle);
2119 dm_pool_issue_prefetches(pool->pmd);
2120 }
2121 }
2122 blk_finish_plug(&plug);
2123}
2124
2125static int cmp_cells(const void *lhs, const void *rhs)
2126{
2127 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2128 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2129
2130 BUG_ON(!lhs_cell->holder);
2131 BUG_ON(!rhs_cell->holder);
2132
2133 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2134 return -1;
2135
2136 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2137 return 1;
2138
2139 return 0;
2140}
2141
2142static unsigned sort_cells(struct pool *pool, struct list_head *cells)
2143{
2144 unsigned count = 0;
2145 struct dm_bio_prison_cell *cell, *tmp;
2146
2147 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2148 if (count >= CELL_SORT_ARRAY_SIZE)
2149 break;
2150
2151 pool->cell_sort_array[count++] = cell;
2152 list_del(&cell->user_list);
2153 }
2154
2155 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2156
2157 return count;
2158}
2159
2160static void process_thin_deferred_cells(struct thin_c *tc)
2161{
2162 struct pool *pool = tc->pool;
2163 unsigned long flags;
2164 struct list_head cells;
2165 struct dm_bio_prison_cell *cell;
2166 unsigned i, j, count;
2167
2168 INIT_LIST_HEAD(&cells);
2169
2170 spin_lock_irqsave(&tc->lock, flags);
2171 list_splice_init(&tc->deferred_cells, &cells);
2172 spin_unlock_irqrestore(&tc->lock, flags);
2173
2174 if (list_empty(&cells))
2175 return;
2176
2177 do {
2178 count = sort_cells(tc->pool, &cells);
2179
2180 for (i = 0; i < count; i++) {
2181 cell = pool->cell_sort_array[i];
2182 BUG_ON(!cell->holder);
2183
2184 /*
2185 * If we've got no free new_mapping structs, and processing
2186 * this bio might require one, we pause until there are some
2187 * prepared mappings to process.
2188 */
2189 if (ensure_next_mapping(pool)) {
2190 for (j = i; j < count; j++)
2191 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2192
2193 spin_lock_irqsave(&tc->lock, flags);
2194 list_splice(&cells, &tc->deferred_cells);
2195 spin_unlock_irqrestore(&tc->lock, flags);
2196 return;
2197 }
2198
2199 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2200 pool->process_discard_cell(tc, cell);
2201 else
2202 pool->process_cell(tc, cell);
2203 }
2204 } while (!list_empty(&cells));
2205}
2206
2207static void thin_get(struct thin_c *tc);
2208static void thin_put(struct thin_c *tc);
2209
2210/*
2211 * We can't hold rcu_read_lock() around code that can block. So we
2212 * find a thin with the rcu lock held; bump a refcount; then drop
2213 * the lock.
2214 */
2215static struct thin_c *get_first_thin(struct pool *pool)
2216{
2217 struct thin_c *tc = NULL;
2218
2219 rcu_read_lock();
2220 if (!list_empty(&pool->active_thins)) {
2221 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
2222 thin_get(tc);
2223 }
2224 rcu_read_unlock();
2225
2226 return tc;
2227}
2228
2229static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2230{
2231 struct thin_c *old_tc = tc;
2232
2233 rcu_read_lock();
2234 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2235 thin_get(tc);
2236 thin_put(old_tc);
2237 rcu_read_unlock();
2238 return tc;
2239 }
2240 thin_put(old_tc);
2241 rcu_read_unlock();
2242
2243 return NULL;
2244}
2245
2246static void process_deferred_bios(struct pool *pool)
2247{
2248 unsigned long flags;
2249 struct bio *bio;
2250 struct bio_list bios;
2251 struct thin_c *tc;
2252
2253 tc = get_first_thin(pool);
2254 while (tc) {
2255 process_thin_deferred_cells(tc);
2256 process_thin_deferred_bios(tc);
2257 tc = get_next_thin(pool, tc);
2258 }
2259
2260 /*
2261 * If there are any deferred flush bios, we must commit
2262 * the metadata before issuing them.
2263 */
2264 bio_list_init(&bios);
2265 spin_lock_irqsave(&pool->lock, flags);
2266 bio_list_merge(&bios, &pool->deferred_flush_bios);
2267 bio_list_init(&pool->deferred_flush_bios);
2268 spin_unlock_irqrestore(&pool->lock, flags);
2269
2270 if (bio_list_empty(&bios) &&
2271 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2272 return;
2273
2274 if (commit(pool)) {
2275 while ((bio = bio_list_pop(&bios)))
2276 bio_io_error(bio);
2277 return;
2278 }
2279 pool->last_commit_jiffies = jiffies;
2280
2281 while ((bio = bio_list_pop(&bios)))
2282 generic_make_request(bio);
2283}
2284
2285static void do_worker(struct work_struct *ws)
2286{
2287 struct pool *pool = container_of(ws, struct pool, worker);
2288
2289 throttle_work_start(&pool->throttle);
2290 dm_pool_issue_prefetches(pool->pmd);
2291 throttle_work_update(&pool->throttle);
2292 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2293 throttle_work_update(&pool->throttle);
2294 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2295 throttle_work_update(&pool->throttle);
2296 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2297 throttle_work_update(&pool->throttle);
2298 process_deferred_bios(pool);
2299 throttle_work_complete(&pool->throttle);
2300}
2301
2302/*
2303 * We want to commit periodically so that not too much
2304 * unwritten data builds up.
2305 */
2306static void do_waker(struct work_struct *ws)
2307{
2308 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2309 wake_worker(pool);
2310 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2311}
2312
2313static void notify_of_pool_mode_change_to_oods(struct pool *pool);
2314
2315/*
2316 * We're holding onto IO to allow userland time to react. After the
2317 * timeout either the pool will have been resized (and thus back in
2318 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2319 */
2320static void do_no_space_timeout(struct work_struct *ws)
2321{
2322 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2323 no_space_timeout);
2324
2325 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2326 pool->pf.error_if_no_space = true;
2327 notify_of_pool_mode_change_to_oods(pool);
2328 error_retry_list_with_code(pool, BLK_STS_NOSPC);
2329 }
2330}
2331
2332/*----------------------------------------------------------------*/
2333
2334struct pool_work {
2335 struct work_struct worker;
2336 struct completion complete;
2337};
2338
2339static struct pool_work *to_pool_work(struct work_struct *ws)
2340{
2341 return container_of(ws, struct pool_work, worker);
2342}
2343
2344static void pool_work_complete(struct pool_work *pw)
2345{
2346 complete(&pw->complete);
2347}
2348
2349static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2350 void (*fn)(struct work_struct *))
2351{
2352 INIT_WORK_ONSTACK(&pw->worker, fn);
2353 init_completion(&pw->complete);
2354 queue_work(pool->wq, &pw->worker);
2355 wait_for_completion(&pw->complete);
2356}
2357
2358/*----------------------------------------------------------------*/
2359
2360struct noflush_work {
2361 struct pool_work pw;
2362 struct thin_c *tc;
2363};
2364
2365static struct noflush_work *to_noflush(struct work_struct *ws)
2366{
2367 return container_of(to_pool_work(ws), struct noflush_work, pw);
2368}
2369
2370static void do_noflush_start(struct work_struct *ws)
2371{
2372 struct noflush_work *w = to_noflush(ws);
2373 w->tc->requeue_mode = true;
2374 requeue_io(w->tc);
2375 pool_work_complete(&w->pw);
2376}
2377
2378static void do_noflush_stop(struct work_struct *ws)
2379{
2380 struct noflush_work *w = to_noflush(ws);
2381 w->tc->requeue_mode = false;
2382 pool_work_complete(&w->pw);
2383}
2384
2385static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2386{
2387 struct noflush_work w;
2388
2389 w.tc = tc;
2390 pool_work_wait(&w.pw, tc->pool, fn);
2391}
2392
2393/*----------------------------------------------------------------*/
2394
2395static enum pool_mode get_pool_mode(struct pool *pool)
2396{
2397 return pool->pf.mode;
2398}
2399
2400static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
2401{
2402 dm_table_event(pool->ti->table);
2403 DMINFO("%s: switching pool to %s mode",
2404 dm_device_name(pool->pool_md), new_mode);
2405}
2406
2407static void notify_of_pool_mode_change_to_oods(struct pool *pool)
2408{
2409 if (!pool->pf.error_if_no_space)
2410 notify_of_pool_mode_change(pool, "out-of-data-space (queue IO)");
2411 else
2412 notify_of_pool_mode_change(pool, "out-of-data-space (error IO)");
2413}
2414
2415static bool passdown_enabled(struct pool_c *pt)
2416{
2417 return pt->adjusted_pf.discard_passdown;
2418}
2419
2420static void set_discard_callbacks(struct pool *pool)
2421{
2422 struct pool_c *pt = pool->ti->private;
2423
2424 if (passdown_enabled(pt)) {
2425 pool->process_discard_cell = process_discard_cell_passdown;
2426 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2427 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2428 } else {
2429 pool->process_discard_cell = process_discard_cell_no_passdown;
2430 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2431 }
2432}
2433
2434static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2435{
2436 struct pool_c *pt = pool->ti->private;
2437 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2438 enum pool_mode old_mode = get_pool_mode(pool);
2439 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
2440
2441 /*
2442 * Never allow the pool to transition to PM_WRITE mode if user
2443 * intervention is required to verify metadata and data consistency.
2444 */
2445 if (new_mode == PM_WRITE && needs_check) {
2446 DMERR("%s: unable to switch pool to write mode until repaired.",
2447 dm_device_name(pool->pool_md));
2448 if (old_mode != new_mode)
2449 new_mode = old_mode;
2450 else
2451 new_mode = PM_READ_ONLY;
2452 }
2453 /*
2454 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2455 * not going to recover without a thin_repair. So we never let the
2456 * pool move out of the old mode.
2457 */
2458 if (old_mode == PM_FAIL)
2459 new_mode = old_mode;
2460
2461 switch (new_mode) {
2462 case PM_FAIL:
2463 if (old_mode != new_mode)
2464 notify_of_pool_mode_change(pool, "failure");
2465 dm_pool_metadata_read_only(pool->pmd);
2466 pool->process_bio = process_bio_fail;
2467 pool->process_discard = process_bio_fail;
2468 pool->process_cell = process_cell_fail;
2469 pool->process_discard_cell = process_cell_fail;
2470 pool->process_prepared_mapping = process_prepared_mapping_fail;
2471 pool->process_prepared_discard = process_prepared_discard_fail;
2472
2473 error_retry_list(pool);
2474 break;
2475
2476 case PM_READ_ONLY:
2477 if (old_mode != new_mode)
2478 notify_of_pool_mode_change(pool, "read-only");
2479 dm_pool_metadata_read_only(pool->pmd);
2480 pool->process_bio = process_bio_read_only;
2481 pool->process_discard = process_bio_success;
2482 pool->process_cell = process_cell_read_only;
2483 pool->process_discard_cell = process_cell_success;
2484 pool->process_prepared_mapping = process_prepared_mapping_fail;
2485 pool->process_prepared_discard = process_prepared_discard_success;
2486
2487 error_retry_list(pool);
2488 break;
2489
2490 case PM_OUT_OF_DATA_SPACE:
2491 /*
2492 * Ideally we'd never hit this state; the low water mark
2493 * would trigger userland to extend the pool before we
2494 * completely run out of data space. However, many small
2495 * IOs to unprovisioned space can consume data space at an
2496 * alarming rate. Adjust your low water mark if you're
2497 * frequently seeing this mode.
2498 */
2499 if (old_mode != new_mode)
2500 notify_of_pool_mode_change_to_oods(pool);
2501 pool->out_of_data_space = true;
2502 pool->process_bio = process_bio_read_only;
2503 pool->process_discard = process_discard_bio;
2504 pool->process_cell = process_cell_read_only;
2505 pool->process_prepared_mapping = process_prepared_mapping;
2506 set_discard_callbacks(pool);
2507
2508 if (!pool->pf.error_if_no_space && no_space_timeout)
2509 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2510 break;
2511
2512 case PM_WRITE:
2513 if (old_mode != new_mode)
2514 notify_of_pool_mode_change(pool, "write");
2515 pool->out_of_data_space = false;
2516 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2517 dm_pool_metadata_read_write(pool->pmd);
2518 pool->process_bio = process_bio;
2519 pool->process_discard = process_discard_bio;
2520 pool->process_cell = process_cell;
2521 pool->process_prepared_mapping = process_prepared_mapping;
2522 set_discard_callbacks(pool);
2523 break;
2524 }
2525
2526 pool->pf.mode = new_mode;
2527 /*
2528 * The pool mode may have changed, sync it so bind_control_target()
2529 * doesn't cause an unexpected mode transition on resume.
2530 */
2531 pt->adjusted_pf.mode = new_mode;
2532}
2533
2534static void abort_transaction(struct pool *pool)
2535{
2536 const char *dev_name = dm_device_name(pool->pool_md);
2537
2538 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2539 if (dm_pool_abort_metadata(pool->pmd)) {
2540 DMERR("%s: failed to abort metadata transaction", dev_name);
2541 set_pool_mode(pool, PM_FAIL);
2542 }
2543
2544 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2545 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2546 set_pool_mode(pool, PM_FAIL);
2547 }
2548}
2549
2550static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2551{
2552 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2553 dm_device_name(pool->pool_md), op, r);
2554
2555 abort_transaction(pool);
2556 set_pool_mode(pool, PM_READ_ONLY);
2557}
2558
2559/*----------------------------------------------------------------*/
2560
2561/*
2562 * Mapping functions.
2563 */
2564
2565/*
2566 * Called only while mapping a thin bio to hand it over to the workqueue.
2567 */
2568static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2569{
2570 unsigned long flags;
2571 struct pool *pool = tc->pool;
2572
2573 spin_lock_irqsave(&tc->lock, flags);
2574 bio_list_add(&tc->deferred_bio_list, bio);
2575 spin_unlock_irqrestore(&tc->lock, flags);
2576
2577 wake_worker(pool);
2578}
2579
2580static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2581{
2582 struct pool *pool = tc->pool;
2583
2584 throttle_lock(&pool->throttle);
2585 thin_defer_bio(tc, bio);
2586 throttle_unlock(&pool->throttle);
2587}
2588
2589static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2590{
2591 unsigned long flags;
2592 struct pool *pool = tc->pool;
2593
2594 throttle_lock(&pool->throttle);
2595 spin_lock_irqsave(&tc->lock, flags);
2596 list_add_tail(&cell->user_list, &tc->deferred_cells);
2597 spin_unlock_irqrestore(&tc->lock, flags);
2598 throttle_unlock(&pool->throttle);
2599
2600 wake_worker(pool);
2601}
2602
2603static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2604{
2605 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2606
2607 h->tc = tc;
2608 h->shared_read_entry = NULL;
2609 h->all_io_entry = NULL;
2610 h->overwrite_mapping = NULL;
2611 h->cell = NULL;
2612}
2613
2614/*
2615 * Non-blocking function called from the thin target's map function.
2616 */
2617static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2618{
2619 int r;
2620 struct thin_c *tc = ti->private;
2621 dm_block_t block = get_bio_block(tc, bio);
2622 struct dm_thin_device *td = tc->td;
2623 struct dm_thin_lookup_result result;
2624 struct dm_bio_prison_cell *virt_cell, *data_cell;
2625 struct dm_cell_key key;
2626
2627 thin_hook_bio(tc, bio);
2628
2629 if (tc->requeue_mode) {
2630 bio->bi_status = BLK_STS_DM_REQUEUE;
2631 bio_endio(bio);
2632 return DM_MAPIO_SUBMITTED;
2633 }
2634
2635 if (get_pool_mode(tc->pool) == PM_FAIL) {
2636 bio_io_error(bio);
2637 return DM_MAPIO_SUBMITTED;
2638 }
2639
2640 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
2641 thin_defer_bio_with_throttle(tc, bio);
2642 return DM_MAPIO_SUBMITTED;
2643 }
2644
2645 /*
2646 * We must hold the virtual cell before doing the lookup, otherwise
2647 * there's a race with discard.
2648 */
2649 build_virtual_key(tc->td, block, &key);
2650 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2651 return DM_MAPIO_SUBMITTED;
2652
2653 r = dm_thin_find_block(td, block, 0, &result);
2654
2655 /*
2656 * Note that we defer readahead too.
2657 */
2658 switch (r) {
2659 case 0:
2660 if (unlikely(result.shared)) {
2661 /*
2662 * We have a race condition here between the
2663 * result.shared value returned by the lookup and
2664 * snapshot creation, which may cause new
2665 * sharing.
2666 *
2667 * To avoid this always quiesce the origin before
2668 * taking the snap. You want to do this anyway to
2669 * ensure a consistent application view
2670 * (i.e. lockfs).
2671 *
2672 * More distant ancestors are irrelevant. The
2673 * shared flag will be set in their case.
2674 */
2675 thin_defer_cell(tc, virt_cell);
2676 return DM_MAPIO_SUBMITTED;
2677 }
2678
2679 build_data_key(tc->td, result.block, &key);
2680 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2681 cell_defer_no_holder(tc, virt_cell);
2682 return DM_MAPIO_SUBMITTED;
2683 }
2684
2685 inc_all_io_entry(tc->pool, bio);
2686 cell_defer_no_holder(tc, data_cell);
2687 cell_defer_no_holder(tc, virt_cell);
2688
2689 remap(tc, bio, result.block);
2690 return DM_MAPIO_REMAPPED;
2691
2692 case -ENODATA:
2693 case -EWOULDBLOCK:
2694 thin_defer_cell(tc, virt_cell);
2695 return DM_MAPIO_SUBMITTED;
2696
2697 default:
2698 /*
2699 * Must always call bio_io_error on failure.
2700 * dm_thin_find_block can fail with -EINVAL if the
2701 * pool is switched to fail-io mode.
2702 */
2703 bio_io_error(bio);
2704 cell_defer_no_holder(tc, virt_cell);
2705 return DM_MAPIO_SUBMITTED;
2706 }
2707}
2708
2709static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2710{
2711 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
2712 struct request_queue *q;
2713
2714 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
2715 return 1;
2716
2717 q = bdev_get_queue(pt->data_dev->bdev);
2718 return bdi_congested(q->backing_dev_info, bdi_bits);
2719}
2720
2721static void requeue_bios(struct pool *pool)
2722{
2723 unsigned long flags;
2724 struct thin_c *tc;
2725
2726 rcu_read_lock();
2727 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2728 spin_lock_irqsave(&tc->lock, flags);
2729 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2730 bio_list_init(&tc->retry_on_resume_list);
2731 spin_unlock_irqrestore(&tc->lock, flags);
2732 }
2733 rcu_read_unlock();
2734}
2735
2736/*----------------------------------------------------------------
2737 * Binding of control targets to a pool object
2738 *--------------------------------------------------------------*/
2739static bool data_dev_supports_discard(struct pool_c *pt)
2740{
2741 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2742
2743 return q && blk_queue_discard(q);
2744}
2745
2746static bool is_factor(sector_t block_size, uint32_t n)
2747{
2748 return !sector_div(block_size, n);
2749}
2750
2751/*
2752 * If discard_passdown was enabled verify that the data device
2753 * supports discards. Disable discard_passdown if not.
2754 */
2755static void disable_passdown_if_not_supported(struct pool_c *pt)
2756{
2757 struct pool *pool = pt->pool;
2758 struct block_device *data_bdev = pt->data_dev->bdev;
2759 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2760 const char *reason = NULL;
2761 char buf[BDEVNAME_SIZE];
2762
2763 if (!pt->adjusted_pf.discard_passdown)
2764 return;
2765
2766 if (!data_dev_supports_discard(pt))
2767 reason = "discard unsupported";
2768
2769 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2770 reason = "max discard sectors smaller than a block";
2771
2772 if (reason) {
2773 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
2774 pt->adjusted_pf.discard_passdown = false;
2775 }
2776}
2777
2778static int bind_control_target(struct pool *pool, struct dm_target *ti)
2779{
2780 struct pool_c *pt = ti->private;
2781
2782 /*
2783 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2784 */
2785 enum pool_mode old_mode = get_pool_mode(pool);
2786 enum pool_mode new_mode = pt->adjusted_pf.mode;
2787
2788 /*
2789 * Don't change the pool's mode until set_pool_mode() below.
2790 * Otherwise the pool's process_* function pointers may
2791 * not match the desired pool mode.
2792 */
2793 pt->adjusted_pf.mode = old_mode;
2794
2795 pool->ti = ti;
2796 pool->pf = pt->adjusted_pf;
2797 pool->low_water_blocks = pt->low_water_blocks;
2798
2799 set_pool_mode(pool, new_mode);
2800
2801 return 0;
2802}
2803
2804static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2805{
2806 if (pool->ti == ti)
2807 pool->ti = NULL;
2808}
2809
2810/*----------------------------------------------------------------
2811 * Pool creation
2812 *--------------------------------------------------------------*/
2813/* Initialize pool features. */
2814static void pool_features_init(struct pool_features *pf)
2815{
2816 pf->mode = PM_WRITE;
2817 pf->zero_new_blocks = true;
2818 pf->discard_enabled = true;
2819 pf->discard_passdown = true;
2820 pf->error_if_no_space = false;
2821}
2822
2823static void __pool_destroy(struct pool *pool)
2824{
2825 __pool_table_remove(pool);
2826
2827 vfree(pool->cell_sort_array);
2828 if (dm_pool_metadata_close(pool->pmd) < 0)
2829 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2830
2831 dm_bio_prison_destroy(pool->prison);
2832 dm_kcopyd_client_destroy(pool->copier);
2833
2834 if (pool->wq)
2835 destroy_workqueue(pool->wq);
2836
2837 if (pool->next_mapping)
2838 mempool_free(pool->next_mapping, pool->mapping_pool);
2839 mempool_destroy(pool->mapping_pool);
2840 dm_deferred_set_destroy(pool->shared_read_ds);
2841 dm_deferred_set_destroy(pool->all_io_ds);
2842 kfree(pool);
2843}
2844
2845static struct kmem_cache *_new_mapping_cache;
2846
2847static struct pool *pool_create(struct mapped_device *pool_md,
2848 struct block_device *metadata_dev,
2849 unsigned long block_size,
2850 int read_only, char **error)
2851{
2852 int r;
2853 void *err_p;
2854 struct pool *pool;
2855 struct dm_pool_metadata *pmd;
2856 bool format_device = read_only ? false : true;
2857
2858 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2859 if (IS_ERR(pmd)) {
2860 *error = "Error creating metadata object";
2861 return (struct pool *)pmd;
2862 }
2863
2864 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
2865 if (!pool) {
2866 *error = "Error allocating memory for pool";
2867 err_p = ERR_PTR(-ENOMEM);
2868 goto bad_pool;
2869 }
2870
2871 pool->pmd = pmd;
2872 pool->sectors_per_block = block_size;
2873 if (block_size & (block_size - 1))
2874 pool->sectors_per_block_shift = -1;
2875 else
2876 pool->sectors_per_block_shift = __ffs(block_size);
2877 pool->low_water_blocks = 0;
2878 pool_features_init(&pool->pf);
2879 pool->prison = dm_bio_prison_create();
2880 if (!pool->prison) {
2881 *error = "Error creating pool's bio prison";
2882 err_p = ERR_PTR(-ENOMEM);
2883 goto bad_prison;
2884 }
2885
2886 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2887 if (IS_ERR(pool->copier)) {
2888 r = PTR_ERR(pool->copier);
2889 *error = "Error creating pool's kcopyd client";
2890 err_p = ERR_PTR(r);
2891 goto bad_kcopyd_client;
2892 }
2893
2894 /*
2895 * Create singlethreaded workqueue that will service all devices
2896 * that use this metadata.
2897 */
2898 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2899 if (!pool->wq) {
2900 *error = "Error creating pool's workqueue";
2901 err_p = ERR_PTR(-ENOMEM);
2902 goto bad_wq;
2903 }
2904
2905 throttle_init(&pool->throttle);
2906 INIT_WORK(&pool->worker, do_worker);
2907 INIT_DELAYED_WORK(&pool->waker, do_waker);
2908 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2909 spin_lock_init(&pool->lock);
2910 bio_list_init(&pool->deferred_flush_bios);
2911 INIT_LIST_HEAD(&pool->prepared_mappings);
2912 INIT_LIST_HEAD(&pool->prepared_discards);
2913 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
2914 INIT_LIST_HEAD(&pool->active_thins);
2915 pool->low_water_triggered = false;
2916 pool->suspended = true;
2917 pool->out_of_data_space = false;
2918
2919 pool->shared_read_ds = dm_deferred_set_create();
2920 if (!pool->shared_read_ds) {
2921 *error = "Error creating pool's shared read deferred set";
2922 err_p = ERR_PTR(-ENOMEM);
2923 goto bad_shared_read_ds;
2924 }
2925
2926 pool->all_io_ds = dm_deferred_set_create();
2927 if (!pool->all_io_ds) {
2928 *error = "Error creating pool's all io deferred set";
2929 err_p = ERR_PTR(-ENOMEM);
2930 goto bad_all_io_ds;
2931 }
2932
2933 pool->next_mapping = NULL;
2934 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
2935 _new_mapping_cache);
2936 if (!pool->mapping_pool) {
2937 *error = "Error creating pool's mapping mempool";
2938 err_p = ERR_PTR(-ENOMEM);
2939 goto bad_mapping_pool;
2940 }
2941
2942 pool->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE);
2943 if (!pool->cell_sort_array) {
2944 *error = "Error allocating cell sort array";
2945 err_p = ERR_PTR(-ENOMEM);
2946 goto bad_sort_array;
2947 }
2948
2949 pool->ref_count = 1;
2950 pool->last_commit_jiffies = jiffies;
2951 pool->pool_md = pool_md;
2952 pool->md_dev = metadata_dev;
2953 __pool_table_insert(pool);
2954
2955 return pool;
2956
2957bad_sort_array:
2958 mempool_destroy(pool->mapping_pool);
2959bad_mapping_pool:
2960 dm_deferred_set_destroy(pool->all_io_ds);
2961bad_all_io_ds:
2962 dm_deferred_set_destroy(pool->shared_read_ds);
2963bad_shared_read_ds:
2964 destroy_workqueue(pool->wq);
2965bad_wq:
2966 dm_kcopyd_client_destroy(pool->copier);
2967bad_kcopyd_client:
2968 dm_bio_prison_destroy(pool->prison);
2969bad_prison:
2970 kfree(pool);
2971bad_pool:
2972 if (dm_pool_metadata_close(pmd))
2973 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2974
2975 return err_p;
2976}
2977
2978static void __pool_inc(struct pool *pool)
2979{
2980 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2981 pool->ref_count++;
2982}
2983
2984static void __pool_dec(struct pool *pool)
2985{
2986 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2987 BUG_ON(!pool->ref_count);
2988 if (!--pool->ref_count)
2989 __pool_destroy(pool);
2990}
2991
2992static struct pool *__pool_find(struct mapped_device *pool_md,
2993 struct block_device *metadata_dev,
2994 unsigned long block_size, int read_only,
2995 char **error, int *created)
2996{
2997 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
2998
2999 if (pool) {
3000 if (pool->pool_md != pool_md) {
3001 *error = "metadata device already in use by a pool";
3002 return ERR_PTR(-EBUSY);
3003 }
3004 __pool_inc(pool);
3005
3006 } else {
3007 pool = __pool_table_lookup(pool_md);
3008 if (pool) {
3009 if (pool->md_dev != metadata_dev) {
3010 *error = "different pool cannot replace a pool";
3011 return ERR_PTR(-EINVAL);
3012 }
3013 __pool_inc(pool);
3014
3015 } else {
3016 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
3017 *created = 1;
3018 }
3019 }
3020
3021 return pool;
3022}
3023
3024/*----------------------------------------------------------------
3025 * Pool target methods
3026 *--------------------------------------------------------------*/
3027static void pool_dtr(struct dm_target *ti)
3028{
3029 struct pool_c *pt = ti->private;
3030
3031 mutex_lock(&dm_thin_pool_table.mutex);
3032
3033 unbind_control_target(pt->pool, ti);
3034 __pool_dec(pt->pool);
3035 dm_put_device(ti, pt->metadata_dev);
3036 dm_put_device(ti, pt->data_dev);
3037 kfree(pt);
3038
3039 mutex_unlock(&dm_thin_pool_table.mutex);
3040}
3041
3042static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3043 struct dm_target *ti)
3044{
3045 int r;
3046 unsigned argc;
3047 const char *arg_name;
3048
3049 static const struct dm_arg _args[] = {
3050 {0, 4, "Invalid number of pool feature arguments"},
3051 };
3052
3053 /*
3054 * No feature arguments supplied.
3055 */
3056 if (!as->argc)
3057 return 0;
3058
3059 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3060 if (r)
3061 return -EINVAL;
3062
3063 while (argc && !r) {
3064 arg_name = dm_shift_arg(as);
3065 argc--;
3066
3067 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3068 pf->zero_new_blocks = false;
3069
3070 else if (!strcasecmp(arg_name, "ignore_discard"))
3071 pf->discard_enabled = false;
3072
3073 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3074 pf->discard_passdown = false;
3075
3076 else if (!strcasecmp(arg_name, "read_only"))
3077 pf->mode = PM_READ_ONLY;
3078
3079 else if (!strcasecmp(arg_name, "error_if_no_space"))
3080 pf->error_if_no_space = true;
3081
3082 else {
3083 ti->error = "Unrecognised pool feature requested";
3084 r = -EINVAL;
3085 break;
3086 }
3087 }
3088
3089 return r;
3090}
3091
3092static void metadata_low_callback(void *context)
3093{
3094 struct pool *pool = context;
3095
3096 DMWARN("%s: reached low water mark for metadata device: sending event.",
3097 dm_device_name(pool->pool_md));
3098
3099 dm_table_event(pool->ti->table);
3100}
3101
3102static sector_t get_dev_size(struct block_device *bdev)
3103{
3104 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
3105}
3106
3107static void warn_if_metadata_device_too_big(struct block_device *bdev)
3108{
3109 sector_t metadata_dev_size = get_dev_size(bdev);
3110 char buffer[BDEVNAME_SIZE];
3111
3112 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3113 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
3114 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
3115}
3116
3117static sector_t get_metadata_dev_size(struct block_device *bdev)
3118{
3119 sector_t metadata_dev_size = get_dev_size(bdev);
3120
3121 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3122 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3123
3124 return metadata_dev_size;
3125}
3126
3127static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3128{
3129 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3130
3131 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3132
3133 return metadata_dev_size;
3134}
3135
3136/*
3137 * When a metadata threshold is crossed a dm event is triggered, and
3138 * userland should respond by growing the metadata device. We could let
3139 * userland set the threshold, like we do with the data threshold, but I'm
3140 * not sure they know enough to do this well.
3141 */
3142static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3143{
3144 /*
3145 * 4M is ample for all ops with the possible exception of thin
3146 * device deletion which is harmless if it fails (just retry the
3147 * delete after you've grown the device).
3148 */
3149 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3150 return min((dm_block_t)1024ULL /* 4M */, quarter);
3151}
3152
3153/*
3154 * thin-pool <metadata dev> <data dev>
3155 * <data block size (sectors)>
3156 * <low water mark (blocks)>
3157 * [<#feature args> [<arg>]*]
3158 *
3159 * Optional feature arguments are:
3160 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3161 * ignore_discard: disable discard
3162 * no_discard_passdown: don't pass discards down to the data device
3163 * read_only: Don't allow any changes to be made to the pool metadata.
3164 * error_if_no_space: error IOs, instead of queueing, if no space.
3165 */
3166static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
3167{
3168 int r, pool_created = 0;
3169 struct pool_c *pt;
3170 struct pool *pool;
3171 struct pool_features pf;
3172 struct dm_arg_set as;
3173 struct dm_dev *data_dev;
3174 unsigned long block_size;
3175 dm_block_t low_water_blocks;
3176 struct dm_dev *metadata_dev;
3177 fmode_t metadata_mode;
3178
3179 /*
3180 * FIXME Remove validation from scope of lock.
3181 */
3182 mutex_lock(&dm_thin_pool_table.mutex);
3183
3184 if (argc < 4) {
3185 ti->error = "Invalid argument count";
3186 r = -EINVAL;
3187 goto out_unlock;
3188 }
3189
3190 as.argc = argc;
3191 as.argv = argv;
3192
3193 /*
3194 * Set default pool features.
3195 */
3196 pool_features_init(&pf);
3197
3198 dm_consume_args(&as, 4);
3199 r = parse_pool_features(&as, &pf, ti);
3200 if (r)
3201 goto out_unlock;
3202
3203 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
3204 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3205 if (r) {
3206 ti->error = "Error opening metadata block device";
3207 goto out_unlock;
3208 }
3209 warn_if_metadata_device_too_big(metadata_dev->bdev);
3210
3211 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
3212 if (r) {
3213 ti->error = "Error getting data device";
3214 goto out_metadata;
3215 }
3216
3217 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3218 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3219 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3220 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3221 ti->error = "Invalid block size";
3222 r = -EINVAL;
3223 goto out;
3224 }
3225
3226 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3227 ti->error = "Invalid low water mark";
3228 r = -EINVAL;
3229 goto out;
3230 }
3231
3232 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3233 if (!pt) {
3234 r = -ENOMEM;
3235 goto out;
3236 }
3237
3238 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
3239 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3240 if (IS_ERR(pool)) {
3241 r = PTR_ERR(pool);
3242 goto out_free_pt;
3243 }
3244
3245 /*
3246 * 'pool_created' reflects whether this is the first table load.
3247 * Top level discard support is not allowed to be changed after
3248 * initial load. This would require a pool reload to trigger thin
3249 * device changes.
3250 */
3251 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3252 ti->error = "Discard support cannot be disabled once enabled";
3253 r = -EINVAL;
3254 goto out_flags_changed;
3255 }
3256
3257 pt->pool = pool;
3258 pt->ti = ti;
3259 pt->metadata_dev = metadata_dev;
3260 pt->data_dev = data_dev;
3261 pt->low_water_blocks = low_water_blocks;
3262 pt->adjusted_pf = pt->requested_pf = pf;
3263 ti->num_flush_bios = 1;
3264
3265 /*
3266 * Only need to enable discards if the pool should pass
3267 * them down to the data device. The thin device's discard
3268 * processing will cause mappings to be removed from the btree.
3269 */
3270 if (pf.discard_enabled && pf.discard_passdown) {
3271 ti->num_discard_bios = 1;
3272
3273 /*
3274 * Setting 'discards_supported' circumvents the normal
3275 * stacking of discard limits (this keeps the pool and
3276 * thin devices' discard limits consistent).
3277 */
3278 ti->discards_supported = true;
3279 }
3280 ti->private = pt;
3281
3282 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
3283 calc_metadata_threshold(pt),
3284 metadata_low_callback,
3285 pool);
3286 if (r)
3287 goto out_flags_changed;
3288
3289 pt->callbacks.congested_fn = pool_is_congested;
3290 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
3291
3292 mutex_unlock(&dm_thin_pool_table.mutex);
3293
3294 return 0;
3295
3296out_flags_changed:
3297 __pool_dec(pool);
3298out_free_pt:
3299 kfree(pt);
3300out:
3301 dm_put_device(ti, data_dev);
3302out_metadata:
3303 dm_put_device(ti, metadata_dev);
3304out_unlock:
3305 mutex_unlock(&dm_thin_pool_table.mutex);
3306
3307 return r;
3308}
3309
3310static int pool_map(struct dm_target *ti, struct bio *bio)
3311{
3312 int r;
3313 struct pool_c *pt = ti->private;
3314 struct pool *pool = pt->pool;
3315 unsigned long flags;
3316
3317 /*
3318 * As this is a singleton target, ti->begin is always zero.
3319 */
3320 spin_lock_irqsave(&pool->lock, flags);
3321 bio_set_dev(bio, pt->data_dev->bdev);
3322 r = DM_MAPIO_REMAPPED;
3323 spin_unlock_irqrestore(&pool->lock, flags);
3324
3325 return r;
3326}
3327
3328static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
3329{
3330 int r;
3331 struct pool_c *pt = ti->private;
3332 struct pool *pool = pt->pool;
3333 sector_t data_size = ti->len;
3334 dm_block_t sb_data_size;
3335
3336 *need_commit = false;
3337
3338 (void) sector_div(data_size, pool->sectors_per_block);
3339
3340 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
3341 if (r) {
3342 DMERR("%s: failed to retrieve data device size",
3343 dm_device_name(pool->pool_md));
3344 return r;
3345 }
3346
3347 if (data_size < sb_data_size) {
3348 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3349 dm_device_name(pool->pool_md),
3350 (unsigned long long)data_size, sb_data_size);
3351 return -EINVAL;
3352
3353 } else if (data_size > sb_data_size) {
3354 if (dm_pool_metadata_needs_check(pool->pmd)) {
3355 DMERR("%s: unable to grow the data device until repaired.",
3356 dm_device_name(pool->pool_md));
3357 return 0;
3358 }
3359
3360 if (sb_data_size)
3361 DMINFO("%s: growing the data device from %llu to %llu blocks",
3362 dm_device_name(pool->pool_md),
3363 sb_data_size, (unsigned long long)data_size);
3364 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3365 if (r) {
3366 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3367 return r;
3368 }
3369
3370 *need_commit = true;
3371 }
3372
3373 return 0;
3374}
3375
3376static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3377{
3378 int r;
3379 struct pool_c *pt = ti->private;
3380 struct pool *pool = pt->pool;
3381 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3382
3383 *need_commit = false;
3384
3385 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3386
3387 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3388 if (r) {
3389 DMERR("%s: failed to retrieve metadata device size",
3390 dm_device_name(pool->pool_md));
3391 return r;
3392 }
3393
3394 if (metadata_dev_size < sb_metadata_dev_size) {
3395 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3396 dm_device_name(pool->pool_md),
3397 metadata_dev_size, sb_metadata_dev_size);
3398 return -EINVAL;
3399
3400 } else if (metadata_dev_size > sb_metadata_dev_size) {
3401 if (dm_pool_metadata_needs_check(pool->pmd)) {
3402 DMERR("%s: unable to grow the metadata device until repaired.",
3403 dm_device_name(pool->pool_md));
3404 return 0;
3405 }
3406
3407 warn_if_metadata_device_too_big(pool->md_dev);
3408 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3409 dm_device_name(pool->pool_md),
3410 sb_metadata_dev_size, metadata_dev_size);
3411 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3412 if (r) {
3413 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3414 return r;
3415 }
3416
3417 *need_commit = true;
3418 }
3419
3420 return 0;
3421}
3422
3423/*
3424 * Retrieves the number of blocks of the data device from
3425 * the superblock and compares it to the actual device size,
3426 * thus resizing the data device in case it has grown.
3427 *
3428 * This both copes with opening preallocated data devices in the ctr
3429 * being followed by a resume
3430 * -and-
3431 * calling the resume method individually after userspace has
3432 * grown the data device in reaction to a table event.
3433 */
3434static int pool_preresume(struct dm_target *ti)
3435{
3436 int r;
3437 bool need_commit1, need_commit2;
3438 struct pool_c *pt = ti->private;
3439 struct pool *pool = pt->pool;
3440
3441 /*
3442 * Take control of the pool object.
3443 */
3444 r = bind_control_target(pool, ti);
3445 if (r)
3446 return r;
3447
3448 r = maybe_resize_data_dev(ti, &need_commit1);
3449 if (r)
3450 return r;
3451
3452 r = maybe_resize_metadata_dev(ti, &need_commit2);
3453 if (r)
3454 return r;
3455
3456 if (need_commit1 || need_commit2)
3457 (void) commit(pool);
3458
3459 return 0;
3460}
3461
3462static void pool_suspend_active_thins(struct pool *pool)
3463{
3464 struct thin_c *tc;
3465
3466 /* Suspend all active thin devices */
3467 tc = get_first_thin(pool);
3468 while (tc) {
3469 dm_internal_suspend_noflush(tc->thin_md);
3470 tc = get_next_thin(pool, tc);
3471 }
3472}
3473
3474static void pool_resume_active_thins(struct pool *pool)
3475{
3476 struct thin_c *tc;
3477
3478 /* Resume all active thin devices */
3479 tc = get_first_thin(pool);
3480 while (tc) {
3481 dm_internal_resume(tc->thin_md);
3482 tc = get_next_thin(pool, tc);
3483 }
3484}
3485
3486static void pool_resume(struct dm_target *ti)
3487{
3488 struct pool_c *pt = ti->private;
3489 struct pool *pool = pt->pool;
3490 unsigned long flags;
3491
3492 /*
3493 * Must requeue active_thins' bios and then resume
3494 * active_thins _before_ clearing 'suspend' flag.
3495 */
3496 requeue_bios(pool);
3497 pool_resume_active_thins(pool);
3498
3499 spin_lock_irqsave(&pool->lock, flags);
3500 pool->low_water_triggered = false;
3501 pool->suspended = false;
3502 spin_unlock_irqrestore(&pool->lock, flags);
3503
3504 do_waker(&pool->waker.work);
3505}
3506
3507static void pool_presuspend(struct dm_target *ti)
3508{
3509 struct pool_c *pt = ti->private;
3510 struct pool *pool = pt->pool;
3511 unsigned long flags;
3512
3513 spin_lock_irqsave(&pool->lock, flags);
3514 pool->suspended = true;
3515 spin_unlock_irqrestore(&pool->lock, flags);
3516
3517 pool_suspend_active_thins(pool);
3518}
3519
3520static void pool_presuspend_undo(struct dm_target *ti)
3521{
3522 struct pool_c *pt = ti->private;
3523 struct pool *pool = pt->pool;
3524 unsigned long flags;
3525
3526 pool_resume_active_thins(pool);
3527
3528 spin_lock_irqsave(&pool->lock, flags);
3529 pool->suspended = false;
3530 spin_unlock_irqrestore(&pool->lock, flags);
3531}
3532
3533static void pool_postsuspend(struct dm_target *ti)
3534{
3535 struct pool_c *pt = ti->private;
3536 struct pool *pool = pt->pool;
3537
3538 cancel_delayed_work_sync(&pool->waker);
3539 cancel_delayed_work_sync(&pool->no_space_timeout);
3540 flush_workqueue(pool->wq);
3541 (void) commit(pool);
3542}
3543
3544static int check_arg_count(unsigned argc, unsigned args_required)
3545{
3546 if (argc != args_required) {
3547 DMWARN("Message received with %u arguments instead of %u.",
3548 argc, args_required);
3549 return -EINVAL;
3550 }
3551
3552 return 0;
3553}
3554
3555static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3556{
3557 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3558 *dev_id <= MAX_DEV_ID)
3559 return 0;
3560
3561 if (warning)
3562 DMWARN("Message received with invalid device id: %s", arg);
3563
3564 return -EINVAL;
3565}
3566
3567static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
3568{
3569 dm_thin_id dev_id;
3570 int r;
3571
3572 r = check_arg_count(argc, 2);
3573 if (r)
3574 return r;
3575
3576 r = read_dev_id(argv[1], &dev_id, 1);
3577 if (r)
3578 return r;
3579
3580 r = dm_pool_create_thin(pool->pmd, dev_id);
3581 if (r) {
3582 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3583 argv[1]);
3584 return r;
3585 }
3586
3587 return 0;
3588}
3589
3590static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3591{
3592 dm_thin_id dev_id;
3593 dm_thin_id origin_dev_id;
3594 int r;
3595
3596 r = check_arg_count(argc, 3);
3597 if (r)
3598 return r;
3599
3600 r = read_dev_id(argv[1], &dev_id, 1);
3601 if (r)
3602 return r;
3603
3604 r = read_dev_id(argv[2], &origin_dev_id, 1);
3605 if (r)
3606 return r;
3607
3608 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3609 if (r) {
3610 DMWARN("Creation of new snapshot %s of device %s failed.",
3611 argv[1], argv[2]);
3612 return r;
3613 }
3614
3615 return 0;
3616}
3617
3618static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
3619{
3620 dm_thin_id dev_id;
3621 int r;
3622
3623 r = check_arg_count(argc, 2);
3624 if (r)
3625 return r;
3626
3627 r = read_dev_id(argv[1], &dev_id, 1);
3628 if (r)
3629 return r;
3630
3631 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3632 if (r)
3633 DMWARN("Deletion of thin device %s failed.", argv[1]);
3634
3635 return r;
3636}
3637
3638static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
3639{
3640 dm_thin_id old_id, new_id;
3641 int r;
3642
3643 r = check_arg_count(argc, 3);
3644 if (r)
3645 return r;
3646
3647 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3648 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3649 return -EINVAL;
3650 }
3651
3652 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3653 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3654 return -EINVAL;
3655 }
3656
3657 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3658 if (r) {
3659 DMWARN("Failed to change transaction id from %s to %s.",
3660 argv[1], argv[2]);
3661 return r;
3662 }
3663
3664 return 0;
3665}
3666
3667static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3668{
3669 int r;
3670
3671 r = check_arg_count(argc, 1);
3672 if (r)
3673 return r;
3674
3675 (void) commit(pool);
3676
3677 r = dm_pool_reserve_metadata_snap(pool->pmd);
3678 if (r)
3679 DMWARN("reserve_metadata_snap message failed.");
3680
3681 return r;
3682}
3683
3684static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
3685{
3686 int r;
3687
3688 r = check_arg_count(argc, 1);
3689 if (r)
3690 return r;
3691
3692 r = dm_pool_release_metadata_snap(pool->pmd);
3693 if (r)
3694 DMWARN("release_metadata_snap message failed.");
3695
3696 return r;
3697}
3698
3699/*
3700 * Messages supported:
3701 * create_thin <dev_id>
3702 * create_snap <dev_id> <origin_id>
3703 * delete <dev_id>
3704 * set_transaction_id <current_trans_id> <new_trans_id>
3705 * reserve_metadata_snap
3706 * release_metadata_snap
3707 */
3708static int pool_message(struct dm_target *ti, unsigned argc, char **argv,
3709 char *result, unsigned maxlen)
3710{
3711 int r = -EINVAL;
3712 struct pool_c *pt = ti->private;
3713 struct pool *pool = pt->pool;
3714
3715 if (get_pool_mode(pool) >= PM_READ_ONLY) {
3716 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3717 dm_device_name(pool->pool_md));
3718 return -EOPNOTSUPP;
3719 }
3720
3721 if (!strcasecmp(argv[0], "create_thin"))
3722 r = process_create_thin_mesg(argc, argv, pool);
3723
3724 else if (!strcasecmp(argv[0], "create_snap"))
3725 r = process_create_snap_mesg(argc, argv, pool);
3726
3727 else if (!strcasecmp(argv[0], "delete"))
3728 r = process_delete_mesg(argc, argv, pool);
3729
3730 else if (!strcasecmp(argv[0], "set_transaction_id"))
3731 r = process_set_transaction_id_mesg(argc, argv, pool);
3732
3733 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3734 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3735
3736 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3737 r = process_release_metadata_snap_mesg(argc, argv, pool);
3738
3739 else
3740 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3741
3742 if (!r)
3743 (void) commit(pool);
3744
3745 return r;
3746}
3747
3748static void emit_flags(struct pool_features *pf, char *result,
3749 unsigned sz, unsigned maxlen)
3750{
3751 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
3752 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3753 pf->error_if_no_space;
3754 DMEMIT("%u ", count);
3755
3756 if (!pf->zero_new_blocks)
3757 DMEMIT("skip_block_zeroing ");
3758
3759 if (!pf->discard_enabled)
3760 DMEMIT("ignore_discard ");
3761
3762 if (!pf->discard_passdown)
3763 DMEMIT("no_discard_passdown ");
3764
3765 if (pf->mode == PM_READ_ONLY)
3766 DMEMIT("read_only ");
3767
3768 if (pf->error_if_no_space)
3769 DMEMIT("error_if_no_space ");
3770}
3771
3772/*
3773 * Status line is:
3774 * <transaction id> <used metadata sectors>/<total metadata sectors>
3775 * <used data sectors>/<total data sectors> <held metadata root>
3776 * <pool mode> <discard config> <no space config> <needs_check>
3777 */
3778static void pool_status(struct dm_target *ti, status_type_t type,
3779 unsigned status_flags, char *result, unsigned maxlen)
3780{
3781 int r;
3782 unsigned sz = 0;
3783 uint64_t transaction_id;
3784 dm_block_t nr_free_blocks_data;
3785 dm_block_t nr_free_blocks_metadata;
3786 dm_block_t nr_blocks_data;
3787 dm_block_t nr_blocks_metadata;
3788 dm_block_t held_root;
3789 char buf[BDEVNAME_SIZE];
3790 char buf2[BDEVNAME_SIZE];
3791 struct pool_c *pt = ti->private;
3792 struct pool *pool = pt->pool;
3793
3794 switch (type) {
3795 case STATUSTYPE_INFO:
3796 if (get_pool_mode(pool) == PM_FAIL) {
3797 DMEMIT("Fail");
3798 break;
3799 }
3800
3801 /* Commit to ensure statistics aren't out-of-date */
3802 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3803 (void) commit(pool);
3804
3805 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3806 if (r) {
3807 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3808 dm_device_name(pool->pool_md), r);
3809 goto err;
3810 }
3811
3812 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3813 if (r) {
3814 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3815 dm_device_name(pool->pool_md), r);
3816 goto err;
3817 }
3818
3819 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3820 if (r) {
3821 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3822 dm_device_name(pool->pool_md), r);
3823 goto err;
3824 }
3825
3826 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3827 if (r) {
3828 DMERR("%s: dm_pool_get_free_block_count returned %d",
3829 dm_device_name(pool->pool_md), r);
3830 goto err;
3831 }
3832
3833 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3834 if (r) {
3835 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3836 dm_device_name(pool->pool_md), r);
3837 goto err;
3838 }
3839
3840 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3841 if (r) {
3842 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3843 dm_device_name(pool->pool_md), r);
3844 goto err;
3845 }
3846
3847 DMEMIT("%llu %llu/%llu %llu/%llu ",
3848 (unsigned long long)transaction_id,
3849 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3850 (unsigned long long)nr_blocks_metadata,
3851 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3852 (unsigned long long)nr_blocks_data);
3853
3854 if (held_root)
3855 DMEMIT("%llu ", held_root);
3856 else
3857 DMEMIT("- ");
3858
3859 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
3860 DMEMIT("out_of_data_space ");
3861 else if (pool->pf.mode == PM_READ_ONLY)
3862 DMEMIT("ro ");
3863 else
3864 DMEMIT("rw ");
3865
3866 if (!pool->pf.discard_enabled)
3867 DMEMIT("ignore_discard ");
3868 else if (pool->pf.discard_passdown)
3869 DMEMIT("discard_passdown ");
3870 else
3871 DMEMIT("no_discard_passdown ");
3872
3873 if (pool->pf.error_if_no_space)
3874 DMEMIT("error_if_no_space ");
3875 else
3876 DMEMIT("queue_if_no_space ");
3877
3878 if (dm_pool_metadata_needs_check(pool->pmd))
3879 DMEMIT("needs_check ");
3880 else
3881 DMEMIT("- ");
3882
3883 break;
3884
3885 case STATUSTYPE_TABLE:
3886 DMEMIT("%s %s %lu %llu ",
3887 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
3888 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
3889 (unsigned long)pool->sectors_per_block,
3890 (unsigned long long)pt->low_water_blocks);
3891 emit_flags(&pt->requested_pf, result, sz, maxlen);
3892 break;
3893 }
3894 return;
3895
3896err:
3897 DMEMIT("Error");
3898}
3899
3900static int pool_iterate_devices(struct dm_target *ti,
3901 iterate_devices_callout_fn fn, void *data)
3902{
3903 struct pool_c *pt = ti->private;
3904
3905 return fn(ti, pt->data_dev, 0, ti->len, data);
3906}
3907
3908static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
3909{
3910 struct pool_c *pt = ti->private;
3911 struct pool *pool = pt->pool;
3912 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3913
3914 /*
3915 * If max_sectors is smaller than pool->sectors_per_block adjust it
3916 * to the highest possible power-of-2 factor of pool->sectors_per_block.
3917 * This is especially beneficial when the pool's data device is a RAID
3918 * device that has a full stripe width that matches pool->sectors_per_block
3919 * -- because even though partial RAID stripe-sized IOs will be issued to a
3920 * single RAID stripe; when aggregated they will end on a full RAID stripe
3921 * boundary.. which avoids additional partial RAID stripe writes cascading
3922 */
3923 if (limits->max_sectors < pool->sectors_per_block) {
3924 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
3925 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3926 limits->max_sectors--;
3927 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3928 }
3929 }
3930
3931 /*
3932 * If the system-determined stacked limits are compatible with the
3933 * pool's blocksize (io_opt is a factor) do not override them.
3934 */
3935 if (io_opt_sectors < pool->sectors_per_block ||
3936 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
3937 if (is_factor(pool->sectors_per_block, limits->max_sectors))
3938 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
3939 else
3940 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
3941 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
3942 }
3943
3944 /*
3945 * pt->adjusted_pf is a staging area for the actual features to use.
3946 * They get transferred to the live pool in bind_control_target()
3947 * called from pool_preresume().
3948 */
3949 if (!pt->adjusted_pf.discard_enabled) {
3950 /*
3951 * Must explicitly disallow stacking discard limits otherwise the
3952 * block layer will stack them if pool's data device has support.
3953 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
3954 * user to see that, so make sure to set all discard limits to 0.
3955 */
3956 limits->discard_granularity = 0;
3957 return;
3958 }
3959
3960 disable_passdown_if_not_supported(pt);
3961
3962 /*
3963 * The pool uses the same discard limits as the underlying data
3964 * device. DM core has already set this up.
3965 */
3966}
3967
3968static struct target_type pool_target = {
3969 .name = "thin-pool",
3970 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
3971 DM_TARGET_IMMUTABLE,
3972 .version = {1, 19, 0},
3973 .module = THIS_MODULE,
3974 .ctr = pool_ctr,
3975 .dtr = pool_dtr,
3976 .map = pool_map,
3977 .presuspend = pool_presuspend,
3978 .presuspend_undo = pool_presuspend_undo,
3979 .postsuspend = pool_postsuspend,
3980 .preresume = pool_preresume,
3981 .resume = pool_resume,
3982 .message = pool_message,
3983 .status = pool_status,
3984 .iterate_devices = pool_iterate_devices,
3985 .io_hints = pool_io_hints,
3986};
3987
3988/*----------------------------------------------------------------
3989 * Thin target methods
3990 *--------------------------------------------------------------*/
3991static void thin_get(struct thin_c *tc)
3992{
3993 atomic_inc(&tc->refcount);
3994}
3995
3996static void thin_put(struct thin_c *tc)
3997{
3998 if (atomic_dec_and_test(&tc->refcount))
3999 complete(&tc->can_destroy);
4000}
4001
4002static void thin_dtr(struct dm_target *ti)
4003{
4004 struct thin_c *tc = ti->private;
4005 unsigned long flags;
4006
4007 spin_lock_irqsave(&tc->pool->lock, flags);
4008 list_del_rcu(&tc->list);
4009 spin_unlock_irqrestore(&tc->pool->lock, flags);
4010 synchronize_rcu();
4011
4012 thin_put(tc);
4013 wait_for_completion(&tc->can_destroy);
4014
4015 mutex_lock(&dm_thin_pool_table.mutex);
4016
4017 __pool_dec(tc->pool);
4018 dm_pool_close_thin_device(tc->td);
4019 dm_put_device(ti, tc->pool_dev);
4020 if (tc->origin_dev)
4021 dm_put_device(ti, tc->origin_dev);
4022 kfree(tc);
4023
4024 mutex_unlock(&dm_thin_pool_table.mutex);
4025}
4026
4027/*
4028 * Thin target parameters:
4029 *
4030 * <pool_dev> <dev_id> [origin_dev]
4031 *
4032 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4033 * dev_id: the internal device identifier
4034 * origin_dev: a device external to the pool that should act as the origin
4035 *
4036 * If the pool device has discards disabled, they get disabled for the thin
4037 * device as well.
4038 */
4039static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
4040{
4041 int r;
4042 struct thin_c *tc;
4043 struct dm_dev *pool_dev, *origin_dev;
4044 struct mapped_device *pool_md;
4045 unsigned long flags;
4046
4047 mutex_lock(&dm_thin_pool_table.mutex);
4048
4049 if (argc != 2 && argc != 3) {
4050 ti->error = "Invalid argument count";
4051 r = -EINVAL;
4052 goto out_unlock;
4053 }
4054
4055 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4056 if (!tc) {
4057 ti->error = "Out of memory";
4058 r = -ENOMEM;
4059 goto out_unlock;
4060 }
4061 tc->thin_md = dm_table_get_md(ti->table);
4062 spin_lock_init(&tc->lock);
4063 INIT_LIST_HEAD(&tc->deferred_cells);
4064 bio_list_init(&tc->deferred_bio_list);
4065 bio_list_init(&tc->retry_on_resume_list);
4066 tc->sort_bio_list = RB_ROOT;
4067
4068 if (argc == 3) {
4069 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
4070 if (r) {
4071 ti->error = "Error opening origin device";
4072 goto bad_origin_dev;
4073 }
4074 tc->origin_dev = origin_dev;
4075 }
4076
4077 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4078 if (r) {
4079 ti->error = "Error opening pool device";
4080 goto bad_pool_dev;
4081 }
4082 tc->pool_dev = pool_dev;
4083
4084 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4085 ti->error = "Invalid device id";
4086 r = -EINVAL;
4087 goto bad_common;
4088 }
4089
4090 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4091 if (!pool_md) {
4092 ti->error = "Couldn't get pool mapped device";
4093 r = -EINVAL;
4094 goto bad_common;
4095 }
4096
4097 tc->pool = __pool_table_lookup(pool_md);
4098 if (!tc->pool) {
4099 ti->error = "Couldn't find pool object";
4100 r = -EINVAL;
4101 goto bad_pool_lookup;
4102 }
4103 __pool_inc(tc->pool);
4104
4105 if (get_pool_mode(tc->pool) == PM_FAIL) {
4106 ti->error = "Couldn't open thin device, Pool is in fail mode";
4107 r = -EINVAL;
4108 goto bad_pool;
4109 }
4110
4111 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4112 if (r) {
4113 ti->error = "Couldn't open thin internal device";
4114 goto bad_pool;
4115 }
4116
4117 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4118 if (r)
4119 goto bad;
4120
4121 ti->num_flush_bios = 1;
4122 ti->flush_supported = true;
4123 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4124
4125 /* In case the pool supports discards, pass them on. */
4126 if (tc->pool->pf.discard_enabled) {
4127 ti->discards_supported = true;
4128 ti->num_discard_bios = 1;
4129 ti->split_discard_bios = false;
4130 }
4131
4132 mutex_unlock(&dm_thin_pool_table.mutex);
4133
4134 spin_lock_irqsave(&tc->pool->lock, flags);
4135 if (tc->pool->suspended) {
4136 spin_unlock_irqrestore(&tc->pool->lock, flags);
4137 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
4138 ti->error = "Unable to activate thin device while pool is suspended";
4139 r = -EINVAL;
4140 goto bad;
4141 }
4142 atomic_set(&tc->refcount, 1);
4143 init_completion(&tc->can_destroy);
4144 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
4145 spin_unlock_irqrestore(&tc->pool->lock, flags);
4146 /*
4147 * This synchronize_rcu() call is needed here otherwise we risk a
4148 * wake_worker() call finding no bios to process (because the newly
4149 * added tc isn't yet visible). So this reduces latency since we
4150 * aren't then dependent on the periodic commit to wake_worker().
4151 */
4152 synchronize_rcu();
4153
4154 dm_put(pool_md);
4155
4156 return 0;
4157
4158bad:
4159 dm_pool_close_thin_device(tc->td);
4160bad_pool:
4161 __pool_dec(tc->pool);
4162bad_pool_lookup:
4163 dm_put(pool_md);
4164bad_common:
4165 dm_put_device(ti, tc->pool_dev);
4166bad_pool_dev:
4167 if (tc->origin_dev)
4168 dm_put_device(ti, tc->origin_dev);
4169bad_origin_dev:
4170 kfree(tc);
4171out_unlock:
4172 mutex_unlock(&dm_thin_pool_table.mutex);
4173
4174 return r;
4175}
4176
4177static int thin_map(struct dm_target *ti, struct bio *bio)
4178{
4179 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
4180
4181 return thin_bio_map(ti, bio);
4182}
4183
4184static int thin_endio(struct dm_target *ti, struct bio *bio,
4185 blk_status_t *err)
4186{
4187 unsigned long flags;
4188 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4189 struct list_head work;
4190 struct dm_thin_new_mapping *m, *tmp;
4191 struct pool *pool = h->tc->pool;
4192
4193 if (h->shared_read_entry) {
4194 INIT_LIST_HEAD(&work);
4195 dm_deferred_entry_dec(h->shared_read_entry, &work);
4196
4197 spin_lock_irqsave(&pool->lock, flags);
4198 list_for_each_entry_safe(m, tmp, &work, list) {
4199 list_del(&m->list);
4200 __complete_mapping_preparation(m);
4201 }
4202 spin_unlock_irqrestore(&pool->lock, flags);
4203 }
4204
4205 if (h->all_io_entry) {
4206 INIT_LIST_HEAD(&work);
4207 dm_deferred_entry_dec(h->all_io_entry, &work);
4208 if (!list_empty(&work)) {
4209 spin_lock_irqsave(&pool->lock, flags);
4210 list_for_each_entry_safe(m, tmp, &work, list)
4211 list_add_tail(&m->list, &pool->prepared_discards);
4212 spin_unlock_irqrestore(&pool->lock, flags);
4213 wake_worker(pool);
4214 }
4215 }
4216
4217 if (h->cell)
4218 cell_defer_no_holder(h->tc, h->cell);
4219
4220 return DM_ENDIO_DONE;
4221}
4222
4223static void thin_presuspend(struct dm_target *ti)
4224{
4225 struct thin_c *tc = ti->private;
4226
4227 if (dm_noflush_suspending(ti))
4228 noflush_work(tc, do_noflush_start);
4229}
4230
4231static void thin_postsuspend(struct dm_target *ti)
4232{
4233 struct thin_c *tc = ti->private;
4234
4235 /*
4236 * The dm_noflush_suspending flag has been cleared by now, so
4237 * unfortunately we must always run this.
4238 */
4239 noflush_work(tc, do_noflush_stop);
4240}
4241
4242static int thin_preresume(struct dm_target *ti)
4243{
4244 struct thin_c *tc = ti->private;
4245
4246 if (tc->origin_dev)
4247 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4248
4249 return 0;
4250}
4251
4252/*
4253 * <nr mapped sectors> <highest mapped sector>
4254 */
4255static void thin_status(struct dm_target *ti, status_type_t type,
4256 unsigned status_flags, char *result, unsigned maxlen)
4257{
4258 int r;
4259 ssize_t sz = 0;
4260 dm_block_t mapped, highest;
4261 char buf[BDEVNAME_SIZE];
4262 struct thin_c *tc = ti->private;
4263
4264 if (get_pool_mode(tc->pool) == PM_FAIL) {
4265 DMEMIT("Fail");
4266 return;
4267 }
4268
4269 if (!tc->td)
4270 DMEMIT("-");
4271 else {
4272 switch (type) {
4273 case STATUSTYPE_INFO:
4274 r = dm_thin_get_mapped_count(tc->td, &mapped);
4275 if (r) {
4276 DMERR("dm_thin_get_mapped_count returned %d", r);
4277 goto err;
4278 }
4279
4280 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4281 if (r < 0) {
4282 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4283 goto err;
4284 }
4285
4286 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4287 if (r)
4288 DMEMIT("%llu", ((highest + 1) *
4289 tc->pool->sectors_per_block) - 1);
4290 else
4291 DMEMIT("-");
4292 break;
4293
4294 case STATUSTYPE_TABLE:
4295 DMEMIT("%s %lu",
4296 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4297 (unsigned long) tc->dev_id);
4298 if (tc->origin_dev)
4299 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4300 break;
4301 }
4302 }
4303
4304 return;
4305
4306err:
4307 DMEMIT("Error");
4308}
4309
4310static int thin_iterate_devices(struct dm_target *ti,
4311 iterate_devices_callout_fn fn, void *data)
4312{
4313 sector_t blocks;
4314 struct thin_c *tc = ti->private;
4315 struct pool *pool = tc->pool;
4316
4317 /*
4318 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4319 * we follow a more convoluted path through to the pool's target.
4320 */
4321 if (!pool->ti)
4322 return 0; /* nothing is bound */
4323
4324 blocks = pool->ti->len;
4325 (void) sector_div(blocks, pool->sectors_per_block);
4326 if (blocks)
4327 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4328
4329 return 0;
4330}
4331
4332static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4333{
4334 struct thin_c *tc = ti->private;
4335 struct pool *pool = tc->pool;
4336
4337 if (!pool->pf.discard_enabled)
4338 return;
4339
4340 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4341 limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */
4342}
4343
4344static struct target_type thin_target = {
4345 .name = "thin",
4346 .version = {1, 19, 0},
4347 .module = THIS_MODULE,
4348 .ctr = thin_ctr,
4349 .dtr = thin_dtr,
4350 .map = thin_map,
4351 .end_io = thin_endio,
4352 .preresume = thin_preresume,
4353 .presuspend = thin_presuspend,
4354 .postsuspend = thin_postsuspend,
4355 .status = thin_status,
4356 .iterate_devices = thin_iterate_devices,
4357 .io_hints = thin_io_hints,
4358};
4359
4360/*----------------------------------------------------------------*/
4361
4362static int __init dm_thin_init(void)
4363{
4364 int r = -ENOMEM;
4365
4366 pool_table_init();
4367
4368 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4369 if (!_new_mapping_cache)
4370 return r;
4371
4372 r = dm_register_target(&thin_target);
4373 if (r)
4374 goto bad_new_mapping_cache;
4375
4376 r = dm_register_target(&pool_target);
4377 if (r)
4378 goto bad_thin_target;
4379
4380 return 0;
4381
4382bad_thin_target:
4383 dm_unregister_target(&thin_target);
4384bad_new_mapping_cache:
4385 kmem_cache_destroy(_new_mapping_cache);
4386
4387 return r;
4388}
4389
4390static void dm_thin_exit(void)
4391{
4392 dm_unregister_target(&thin_target);
4393 dm_unregister_target(&pool_target);
4394
4395 kmem_cache_destroy(_new_mapping_cache);
4396
4397 pool_table_exit();
4398}
4399
4400module_init(dm_thin_init);
4401module_exit(dm_thin_exit);
4402
4403module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
4404MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4405
4406MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4407MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
4408MODULE_LICENSE("GPL");