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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 return r;
464}
465
466static void cell_release(struct pool *pool,
467 struct dm_bio_prison_cell *cell,
468 struct bio_list *bios)
469{
470 dm_cell_release(pool->prison, cell, bios);
471 dm_bio_prison_free_cell(pool->prison, cell);
472}
473
474static void cell_visit_release(struct pool *pool,
475 void (*fn)(void *, struct dm_bio_prison_cell *),
476 void *context,
477 struct dm_bio_prison_cell *cell)
478{
479 dm_cell_visit_release(pool->prison, fn, context, cell);
480 dm_bio_prison_free_cell(pool->prison, cell);
481}
482
483static void cell_release_no_holder(struct pool *pool,
484 struct dm_bio_prison_cell *cell,
485 struct bio_list *bios)
486{
487 dm_cell_release_no_holder(pool->prison, cell, bios);
488 dm_bio_prison_free_cell(pool->prison, cell);
489}
490
491static void cell_error_with_code(struct pool *pool,
492 struct dm_bio_prison_cell *cell, blk_status_t error_code)
493{
494 dm_cell_error(pool->prison, cell, error_code);
495 dm_bio_prison_free_cell(pool->prison, cell);
496}
497
498static blk_status_t get_pool_io_error_code(struct pool *pool)
499{
500 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
501}
502
503static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
504{
505 cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
506}
507
508static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
509{
510 cell_error_with_code(pool, cell, 0);
511}
512
513static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
514{
515 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
516}
517
518/*----------------------------------------------------------------*/
519
520/*
521 * A global list of pools that uses a struct mapped_device as a key.
522 */
523static struct dm_thin_pool_table {
524 struct mutex mutex;
525 struct list_head pools;
526} dm_thin_pool_table;
527
528static void pool_table_init(void)
529{
530 mutex_init(&dm_thin_pool_table.mutex);
531 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
532}
533
534static void pool_table_exit(void)
535{
536 mutex_destroy(&dm_thin_pool_table.mutex);
537}
538
539static void __pool_table_insert(struct pool *pool)
540{
541 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
542 list_add(&pool->list, &dm_thin_pool_table.pools);
543}
544
545static void __pool_table_remove(struct pool *pool)
546{
547 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
548 list_del(&pool->list);
549}
550
551static struct pool *__pool_table_lookup(struct mapped_device *md)
552{
553 struct pool *pool = NULL, *tmp;
554
555 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
556
557 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
558 if (tmp->pool_md == md) {
559 pool = tmp;
560 break;
561 }
562 }
563
564 return pool;
565}
566
567static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
568{
569 struct pool *pool = NULL, *tmp;
570
571 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
572
573 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
574 if (tmp->md_dev == md_dev) {
575 pool = tmp;
576 break;
577 }
578 }
579
580 return pool;
581}
582
583/*----------------------------------------------------------------*/
584
585struct dm_thin_endio_hook {
586 struct thin_c *tc;
587 struct dm_deferred_entry *shared_read_entry;
588 struct dm_deferred_entry *all_io_entry;
589 struct dm_thin_new_mapping *overwrite_mapping;
590 struct rb_node rb_node;
591 struct dm_bio_prison_cell *cell;
592};
593
594static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
595{
596 bio_list_merge(bios, master);
597 bio_list_init(master);
598}
599
600static void error_bio_list(struct bio_list *bios, blk_status_t error)
601{
602 struct bio *bio;
603
604 while ((bio = bio_list_pop(bios))) {
605 bio->bi_status = error;
606 bio_endio(bio);
607 }
608}
609
610static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
611 blk_status_t error)
612{
613 struct bio_list bios;
614
615 bio_list_init(&bios);
616
617 spin_lock_irq(&tc->lock);
618 __merge_bio_list(&bios, master);
619 spin_unlock_irq(&tc->lock);
620
621 error_bio_list(&bios, error);
622}
623
624static void requeue_deferred_cells(struct thin_c *tc)
625{
626 struct pool *pool = tc->pool;
627 struct list_head cells;
628 struct dm_bio_prison_cell *cell, *tmp;
629
630 INIT_LIST_HEAD(&cells);
631
632 spin_lock_irq(&tc->lock);
633 list_splice_init(&tc->deferred_cells, &cells);
634 spin_unlock_irq(&tc->lock);
635
636 list_for_each_entry_safe(cell, tmp, &cells, user_list)
637 cell_requeue(pool, cell);
638}
639
640static void requeue_io(struct thin_c *tc)
641{
642 struct bio_list bios;
643
644 bio_list_init(&bios);
645
646 spin_lock_irq(&tc->lock);
647 __merge_bio_list(&bios, &tc->deferred_bio_list);
648 __merge_bio_list(&bios, &tc->retry_on_resume_list);
649 spin_unlock_irq(&tc->lock);
650
651 error_bio_list(&bios, BLK_STS_DM_REQUEUE);
652 requeue_deferred_cells(tc);
653}
654
655static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
656{
657 struct thin_c *tc;
658
659 rcu_read_lock();
660 list_for_each_entry_rcu(tc, &pool->active_thins, list)
661 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
662 rcu_read_unlock();
663}
664
665static void error_retry_list(struct pool *pool)
666{
667 error_retry_list_with_code(pool, get_pool_io_error_code(pool));
668}
669
670/*
671 * This section of code contains the logic for processing a thin device's IO.
672 * Much of the code depends on pool object resources (lists, workqueues, etc)
673 * but most is exclusively called from the thin target rather than the thin-pool
674 * target.
675 */
676
677static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
678{
679 struct pool *pool = tc->pool;
680 sector_t block_nr = bio->bi_iter.bi_sector;
681
682 if (block_size_is_power_of_two(pool))
683 block_nr >>= pool->sectors_per_block_shift;
684 else
685 (void) sector_div(block_nr, pool->sectors_per_block);
686
687 return block_nr;
688}
689
690/*
691 * Returns the _complete_ blocks that this bio covers.
692 */
693static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
694 dm_block_t *begin, dm_block_t *end)
695{
696 struct pool *pool = tc->pool;
697 sector_t b = bio->bi_iter.bi_sector;
698 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
699
700 b += pool->sectors_per_block - 1ull; /* so we round up */
701
702 if (block_size_is_power_of_two(pool)) {
703 b >>= pool->sectors_per_block_shift;
704 e >>= pool->sectors_per_block_shift;
705 } else {
706 (void) sector_div(b, pool->sectors_per_block);
707 (void) sector_div(e, pool->sectors_per_block);
708 }
709
710 if (e < b)
711 /* Can happen if the bio is within a single block. */
712 e = b;
713
714 *begin = b;
715 *end = e;
716}
717
718static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
719{
720 struct pool *pool = tc->pool;
721 sector_t bi_sector = bio->bi_iter.bi_sector;
722
723 bio_set_dev(bio, tc->pool_dev->bdev);
724 if (block_size_is_power_of_two(pool))
725 bio->bi_iter.bi_sector =
726 (block << pool->sectors_per_block_shift) |
727 (bi_sector & (pool->sectors_per_block - 1));
728 else
729 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
730 sector_div(bi_sector, pool->sectors_per_block);
731}
732
733static void remap_to_origin(struct thin_c *tc, struct bio *bio)
734{
735 bio_set_dev(bio, tc->origin_dev->bdev);
736}
737
738static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
739{
740 return op_is_flush(bio->bi_opf) &&
741 dm_thin_changed_this_transaction(tc->td);
742}
743
744static void inc_all_io_entry(struct pool *pool, struct bio *bio)
745{
746 struct dm_thin_endio_hook *h;
747
748 if (bio_op(bio) == REQ_OP_DISCARD)
749 return;
750
751 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
752 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
753}
754
755static void issue(struct thin_c *tc, struct bio *bio)
756{
757 struct pool *pool = tc->pool;
758
759 if (!bio_triggers_commit(tc, bio)) {
760 dm_submit_bio_remap(bio, NULL);
761 return;
762 }
763
764 /*
765 * Complete bio with an error if earlier I/O caused changes to
766 * the metadata that can't be committed e.g, due to I/O errors
767 * on the metadata device.
768 */
769 if (dm_thin_aborted_changes(tc->td)) {
770 bio_io_error(bio);
771 return;
772 }
773
774 /*
775 * Batch together any bios that trigger commits and then issue a
776 * single commit for them in process_deferred_bios().
777 */
778 spin_lock_irq(&pool->lock);
779 bio_list_add(&pool->deferred_flush_bios, bio);
780 spin_unlock_irq(&pool->lock);
781}
782
783static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
784{
785 remap_to_origin(tc, bio);
786 issue(tc, bio);
787}
788
789static void remap_and_issue(struct thin_c *tc, struct bio *bio,
790 dm_block_t block)
791{
792 remap(tc, bio, block);
793 issue(tc, bio);
794}
795
796/*----------------------------------------------------------------*/
797
798/*
799 * Bio endio functions.
800 */
801struct dm_thin_new_mapping {
802 struct list_head list;
803
804 bool pass_discard:1;
805 bool maybe_shared:1;
806
807 /*
808 * Track quiescing, copying and zeroing preparation actions. When this
809 * counter hits zero the block is prepared and can be inserted into the
810 * btree.
811 */
812 atomic_t prepare_actions;
813
814 blk_status_t status;
815 struct thin_c *tc;
816 dm_block_t virt_begin, virt_end;
817 dm_block_t data_block;
818 struct dm_bio_prison_cell *cell;
819
820 /*
821 * If the bio covers the whole area of a block then we can avoid
822 * zeroing or copying. Instead this bio is hooked. The bio will
823 * still be in the cell, so care has to be taken to avoid issuing
824 * the bio twice.
825 */
826 struct bio *bio;
827 bio_end_io_t *saved_bi_end_io;
828};
829
830static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
831{
832 struct pool *pool = m->tc->pool;
833
834 if (atomic_dec_and_test(&m->prepare_actions)) {
835 list_add_tail(&m->list, &pool->prepared_mappings);
836 wake_worker(pool);
837 }
838}
839
840static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
841{
842 unsigned long flags;
843 struct pool *pool = m->tc->pool;
844
845 spin_lock_irqsave(&pool->lock, flags);
846 __complete_mapping_preparation(m);
847 spin_unlock_irqrestore(&pool->lock, flags);
848}
849
850static void copy_complete(int read_err, unsigned long write_err, void *context)
851{
852 struct dm_thin_new_mapping *m = context;
853
854 m->status = read_err || write_err ? BLK_STS_IOERR : 0;
855 complete_mapping_preparation(m);
856}
857
858static void overwrite_endio(struct bio *bio)
859{
860 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
861 struct dm_thin_new_mapping *m = h->overwrite_mapping;
862
863 bio->bi_end_io = m->saved_bi_end_io;
864
865 m->status = bio->bi_status;
866 complete_mapping_preparation(m);
867}
868
869/*----------------------------------------------------------------*/
870
871/*
872 * Workqueue.
873 */
874
875/*
876 * Prepared mapping jobs.
877 */
878
879/*
880 * This sends the bios in the cell, except the original holder, back
881 * to the deferred_bios list.
882 */
883static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
884{
885 struct pool *pool = tc->pool;
886 unsigned long flags;
887 struct bio_list bios;
888
889 bio_list_init(&bios);
890 cell_release_no_holder(pool, cell, &bios);
891
892 if (!bio_list_empty(&bios)) {
893 spin_lock_irqsave(&tc->lock, flags);
894 bio_list_merge(&tc->deferred_bio_list, &bios);
895 spin_unlock_irqrestore(&tc->lock, flags);
896 wake_worker(pool);
897 }
898}
899
900static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
901
902struct remap_info {
903 struct thin_c *tc;
904 struct bio_list defer_bios;
905 struct bio_list issue_bios;
906};
907
908static void __inc_remap_and_issue_cell(void *context,
909 struct dm_bio_prison_cell *cell)
910{
911 struct remap_info *info = context;
912 struct bio *bio;
913
914 while ((bio = bio_list_pop(&cell->bios))) {
915 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
916 bio_list_add(&info->defer_bios, bio);
917 else {
918 inc_all_io_entry(info->tc->pool, bio);
919
920 /*
921 * We can't issue the bios with the bio prison lock
922 * held, so we add them to a list to issue on
923 * return from this function.
924 */
925 bio_list_add(&info->issue_bios, bio);
926 }
927 }
928}
929
930static void inc_remap_and_issue_cell(struct thin_c *tc,
931 struct dm_bio_prison_cell *cell,
932 dm_block_t block)
933{
934 struct bio *bio;
935 struct remap_info info;
936
937 info.tc = tc;
938 bio_list_init(&info.defer_bios);
939 bio_list_init(&info.issue_bios);
940
941 /*
942 * We have to be careful to inc any bios we're about to issue
943 * before the cell is released, and avoid a race with new bios
944 * being added to the cell.
945 */
946 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
947 &info, cell);
948
949 while ((bio = bio_list_pop(&info.defer_bios)))
950 thin_defer_bio(tc, bio);
951
952 while ((bio = bio_list_pop(&info.issue_bios)))
953 remap_and_issue(info.tc, bio, block);
954}
955
956static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
957{
958 cell_error(m->tc->pool, m->cell);
959 list_del(&m->list);
960 mempool_free(m, &m->tc->pool->mapping_pool);
961}
962
963static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio)
964{
965 struct pool *pool = tc->pool;
966
967 /*
968 * If the bio has the REQ_FUA flag set we must commit the metadata
969 * before signaling its completion.
970 */
971 if (!bio_triggers_commit(tc, bio)) {
972 bio_endio(bio);
973 return;
974 }
975
976 /*
977 * Complete bio with an error if earlier I/O caused changes to the
978 * metadata that can't be committed, e.g, due to I/O errors on the
979 * metadata device.
980 */
981 if (dm_thin_aborted_changes(tc->td)) {
982 bio_io_error(bio);
983 return;
984 }
985
986 /*
987 * Batch together any bios that trigger commits and then issue a
988 * single commit for them in process_deferred_bios().
989 */
990 spin_lock_irq(&pool->lock);
991 bio_list_add(&pool->deferred_flush_completions, bio);
992 spin_unlock_irq(&pool->lock);
993}
994
995static void process_prepared_mapping(struct dm_thin_new_mapping *m)
996{
997 struct thin_c *tc = m->tc;
998 struct pool *pool = tc->pool;
999 struct bio *bio = m->bio;
1000 int r;
1001
1002 if (m->status) {
1003 cell_error(pool, m->cell);
1004 goto out;
1005 }
1006
1007 /*
1008 * Commit the prepared block into the mapping btree.
1009 * Any I/O for this block arriving after this point will get
1010 * remapped to it directly.
1011 */
1012 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
1013 if (r) {
1014 metadata_operation_failed(pool, "dm_thin_insert_block", r);
1015 cell_error(pool, m->cell);
1016 goto out;
1017 }
1018
1019 /*
1020 * Release any bios held while the block was being provisioned.
1021 * If we are processing a write bio that completely covers the block,
1022 * we already processed it so can ignore it now when processing
1023 * the bios in the cell.
1024 */
1025 if (bio) {
1026 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1027 complete_overwrite_bio(tc, bio);
1028 } else {
1029 inc_all_io_entry(tc->pool, m->cell->holder);
1030 remap_and_issue(tc, m->cell->holder, m->data_block);
1031 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1032 }
1033
1034out:
1035 list_del(&m->list);
1036 mempool_free(m, &pool->mapping_pool);
1037}
1038
1039/*----------------------------------------------------------------*/
1040
1041static void free_discard_mapping(struct dm_thin_new_mapping *m)
1042{
1043 struct thin_c *tc = m->tc;
1044
1045 if (m->cell)
1046 cell_defer_no_holder(tc, m->cell);
1047 mempool_free(m, &tc->pool->mapping_pool);
1048}
1049
1050static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
1051{
1052 bio_io_error(m->bio);
1053 free_discard_mapping(m);
1054}
1055
1056static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
1057{
1058 bio_endio(m->bio);
1059 free_discard_mapping(m);
1060}
1061
1062static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
1063{
1064 int r;
1065 struct thin_c *tc = m->tc;
1066
1067 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
1068 if (r) {
1069 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
1070 bio_io_error(m->bio);
1071 } else
1072 bio_endio(m->bio);
1073
1074 cell_defer_no_holder(tc, m->cell);
1075 mempool_free(m, &tc->pool->mapping_pool);
1076}
1077
1078/*----------------------------------------------------------------*/
1079
1080static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
1081 struct bio *discard_parent)
1082{
1083 /*
1084 * We've already unmapped this range of blocks, but before we
1085 * passdown we have to check that these blocks are now unused.
1086 */
1087 int r = 0;
1088 bool shared = true;
1089 struct thin_c *tc = m->tc;
1090 struct pool *pool = tc->pool;
1091 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
1092 struct discard_op op;
1093
1094 begin_discard(&op, tc, discard_parent);
1095 while (b != end) {
1096 /* find start of unmapped run */
1097 for (; b < end; b++) {
1098 r = dm_pool_block_is_shared(pool->pmd, b, &shared);
1099 if (r)
1100 goto out;
1101
1102 if (!shared)
1103 break;
1104 }
1105
1106 if (b == end)
1107 break;
1108
1109 /* find end of run */
1110 for (e = b + 1; e != end; e++) {
1111 r = dm_pool_block_is_shared(pool->pmd, e, &shared);
1112 if (r)
1113 goto out;
1114
1115 if (shared)
1116 break;
1117 }
1118
1119 r = issue_discard(&op, b, e);
1120 if (r)
1121 goto out;
1122
1123 b = e;
1124 }
1125out:
1126 end_discard(&op, r);
1127}
1128
1129static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
1130{
1131 unsigned long flags;
1132 struct pool *pool = m->tc->pool;
1133
1134 spin_lock_irqsave(&pool->lock, flags);
1135 list_add_tail(&m->list, &pool->prepared_discards_pt2);
1136 spin_unlock_irqrestore(&pool->lock, flags);
1137 wake_worker(pool);
1138}
1139
1140static void passdown_endio(struct bio *bio)
1141{
1142 /*
1143 * It doesn't matter if the passdown discard failed, we still want
1144 * to unmap (we ignore err).
1145 */
1146 queue_passdown_pt2(bio->bi_private);
1147 bio_put(bio);
1148}
1149
1150static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
1151{
1152 int r;
1153 struct thin_c *tc = m->tc;
1154 struct pool *pool = tc->pool;
1155 struct bio *discard_parent;
1156 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
1157
1158 /*
1159 * Only this thread allocates blocks, so we can be sure that the
1160 * newly unmapped blocks will not be allocated before the end of
1161 * the function.
1162 */
1163 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
1164 if (r) {
1165 metadata_operation_failed(pool, "dm_thin_remove_range", r);
1166 bio_io_error(m->bio);
1167 cell_defer_no_holder(tc, m->cell);
1168 mempool_free(m, &pool->mapping_pool);
1169 return;
1170 }
1171
1172 /*
1173 * Increment the unmapped blocks. This prevents a race between the
1174 * passdown io and reallocation of freed blocks.
1175 */
1176 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
1177 if (r) {
1178 metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
1179 bio_io_error(m->bio);
1180 cell_defer_no_holder(tc, m->cell);
1181 mempool_free(m, &pool->mapping_pool);
1182 return;
1183 }
1184
1185 discard_parent = bio_alloc(NULL, 1, 0, GFP_NOIO);
1186 discard_parent->bi_end_io = passdown_endio;
1187 discard_parent->bi_private = m;
1188 if (m->maybe_shared)
1189 passdown_double_checking_shared_status(m, discard_parent);
1190 else {
1191 struct discard_op op;
1192
1193 begin_discard(&op, tc, discard_parent);
1194 r = issue_discard(&op, m->data_block, data_end);
1195 end_discard(&op, r);
1196 }
1197}
1198
1199static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1200{
1201 int r;
1202 struct thin_c *tc = m->tc;
1203 struct pool *pool = tc->pool;
1204
1205 /*
1206 * The passdown has completed, so now we can decrement all those
1207 * unmapped blocks.
1208 */
1209 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1210 m->data_block + (m->virt_end - m->virt_begin));
1211 if (r) {
1212 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1213 bio_io_error(m->bio);
1214 } else
1215 bio_endio(m->bio);
1216
1217 cell_defer_no_holder(tc, m->cell);
1218 mempool_free(m, &pool->mapping_pool);
1219}
1220
1221static void process_prepared(struct pool *pool, struct list_head *head,
1222 process_mapping_fn *fn)
1223{
1224 struct list_head maps;
1225 struct dm_thin_new_mapping *m, *tmp;
1226
1227 INIT_LIST_HEAD(&maps);
1228 spin_lock_irq(&pool->lock);
1229 list_splice_init(head, &maps);
1230 spin_unlock_irq(&pool->lock);
1231
1232 list_for_each_entry_safe(m, tmp, &maps, list)
1233 (*fn)(m);
1234}
1235
1236/*
1237 * Deferred bio jobs.
1238 */
1239static int io_overlaps_block(struct pool *pool, struct bio *bio)
1240{
1241 return bio->bi_iter.bi_size ==
1242 (pool->sectors_per_block << SECTOR_SHIFT);
1243}
1244
1245static int io_overwrites_block(struct pool *pool, struct bio *bio)
1246{
1247 return (bio_data_dir(bio) == WRITE) &&
1248 io_overlaps_block(pool, bio);
1249}
1250
1251static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1252 bio_end_io_t *fn)
1253{
1254 *save = bio->bi_end_io;
1255 bio->bi_end_io = fn;
1256}
1257
1258static int ensure_next_mapping(struct pool *pool)
1259{
1260 if (pool->next_mapping)
1261 return 0;
1262
1263 pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC);
1264
1265 return pool->next_mapping ? 0 : -ENOMEM;
1266}
1267
1268static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1269{
1270 struct dm_thin_new_mapping *m = pool->next_mapping;
1271
1272 BUG_ON(!pool->next_mapping);
1273
1274 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1275 INIT_LIST_HEAD(&m->list);
1276 m->bio = NULL;
1277
1278 pool->next_mapping = NULL;
1279
1280 return m;
1281}
1282
1283static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1284 sector_t begin, sector_t end)
1285{
1286 struct dm_io_region to;
1287
1288 to.bdev = tc->pool_dev->bdev;
1289 to.sector = begin;
1290 to.count = end - begin;
1291
1292 dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1293}
1294
1295static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1296 dm_block_t data_begin,
1297 struct dm_thin_new_mapping *m)
1298{
1299 struct pool *pool = tc->pool;
1300 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1301
1302 h->overwrite_mapping = m;
1303 m->bio = bio;
1304 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1305 inc_all_io_entry(pool, bio);
1306 remap_and_issue(tc, bio, data_begin);
1307}
1308
1309/*
1310 * A partial copy also needs to zero the uncopied region.
1311 */
1312static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1313 struct dm_dev *origin, dm_block_t data_origin,
1314 dm_block_t data_dest,
1315 struct dm_bio_prison_cell *cell, struct bio *bio,
1316 sector_t len)
1317{
1318 struct pool *pool = tc->pool;
1319 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1320
1321 m->tc = tc;
1322 m->virt_begin = virt_block;
1323 m->virt_end = virt_block + 1u;
1324 m->data_block = data_dest;
1325 m->cell = cell;
1326
1327 /*
1328 * quiesce action + copy action + an extra reference held for the
1329 * duration of this function (we may need to inc later for a
1330 * partial zero).
1331 */
1332 atomic_set(&m->prepare_actions, 3);
1333
1334 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1335 complete_mapping_preparation(m); /* already quiesced */
1336
1337 /*
1338 * IO to pool_dev remaps to the pool target's data_dev.
1339 *
1340 * If the whole block of data is being overwritten, we can issue the
1341 * bio immediately. Otherwise we use kcopyd to clone the data first.
1342 */
1343 if (io_overwrites_block(pool, bio))
1344 remap_and_issue_overwrite(tc, bio, data_dest, m);
1345 else {
1346 struct dm_io_region from, to;
1347
1348 from.bdev = origin->bdev;
1349 from.sector = data_origin * pool->sectors_per_block;
1350 from.count = len;
1351
1352 to.bdev = tc->pool_dev->bdev;
1353 to.sector = data_dest * pool->sectors_per_block;
1354 to.count = len;
1355
1356 dm_kcopyd_copy(pool->copier, &from, 1, &to,
1357 0, copy_complete, m);
1358
1359 /*
1360 * Do we need to zero a tail region?
1361 */
1362 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1363 atomic_inc(&m->prepare_actions);
1364 ll_zero(tc, m,
1365 data_dest * pool->sectors_per_block + len,
1366 (data_dest + 1) * pool->sectors_per_block);
1367 }
1368 }
1369
1370 complete_mapping_preparation(m); /* drop our ref */
1371}
1372
1373static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1374 dm_block_t data_origin, dm_block_t data_dest,
1375 struct dm_bio_prison_cell *cell, struct bio *bio)
1376{
1377 schedule_copy(tc, virt_block, tc->pool_dev,
1378 data_origin, data_dest, cell, bio,
1379 tc->pool->sectors_per_block);
1380}
1381
1382static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1383 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1384 struct bio *bio)
1385{
1386 struct pool *pool = tc->pool;
1387 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1388
1389 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1390 m->tc = tc;
1391 m->virt_begin = virt_block;
1392 m->virt_end = virt_block + 1u;
1393 m->data_block = data_block;
1394 m->cell = cell;
1395
1396 /*
1397 * If the whole block of data is being overwritten or we are not
1398 * zeroing pre-existing data, we can issue the bio immediately.
1399 * Otherwise we use kcopyd to zero the data first.
1400 */
1401 if (pool->pf.zero_new_blocks) {
1402 if (io_overwrites_block(pool, bio))
1403 remap_and_issue_overwrite(tc, bio, data_block, m);
1404 else
1405 ll_zero(tc, m, data_block * pool->sectors_per_block,
1406 (data_block + 1) * pool->sectors_per_block);
1407 } else
1408 process_prepared_mapping(m);
1409}
1410
1411static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1412 dm_block_t data_dest,
1413 struct dm_bio_prison_cell *cell, struct bio *bio)
1414{
1415 struct pool *pool = tc->pool;
1416 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1417 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1418
1419 if (virt_block_end <= tc->origin_size)
1420 schedule_copy(tc, virt_block, tc->origin_dev,
1421 virt_block, data_dest, cell, bio,
1422 pool->sectors_per_block);
1423
1424 else if (virt_block_begin < tc->origin_size)
1425 schedule_copy(tc, virt_block, tc->origin_dev,
1426 virt_block, data_dest, cell, bio,
1427 tc->origin_size - virt_block_begin);
1428
1429 else
1430 schedule_zero(tc, virt_block, data_dest, cell, bio);
1431}
1432
1433static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1434
1435static void requeue_bios(struct pool *pool);
1436
1437static bool is_read_only_pool_mode(enum pool_mode mode)
1438{
1439 return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY);
1440}
1441
1442static bool is_read_only(struct pool *pool)
1443{
1444 return is_read_only_pool_mode(get_pool_mode(pool));
1445}
1446
1447static void check_for_metadata_space(struct pool *pool)
1448{
1449 int r;
1450 const char *ooms_reason = NULL;
1451 dm_block_t nr_free;
1452
1453 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free);
1454 if (r)
1455 ooms_reason = "Could not get free metadata blocks";
1456 else if (!nr_free)
1457 ooms_reason = "No free metadata blocks";
1458
1459 if (ooms_reason && !is_read_only(pool)) {
1460 DMERR("%s", ooms_reason);
1461 set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE);
1462 }
1463}
1464
1465static void check_for_data_space(struct pool *pool)
1466{
1467 int r;
1468 dm_block_t nr_free;
1469
1470 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1471 return;
1472
1473 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1474 if (r)
1475 return;
1476
1477 if (nr_free) {
1478 set_pool_mode(pool, PM_WRITE);
1479 requeue_bios(pool);
1480 }
1481}
1482
1483/*
1484 * A non-zero return indicates read_only or fail_io mode.
1485 * Many callers don't care about the return value.
1486 */
1487static int commit(struct pool *pool)
1488{
1489 int r;
1490
1491 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE)
1492 return -EINVAL;
1493
1494 r = dm_pool_commit_metadata(pool->pmd);
1495 if (r)
1496 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1497 else {
1498 check_for_metadata_space(pool);
1499 check_for_data_space(pool);
1500 }
1501
1502 return r;
1503}
1504
1505static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1506{
1507 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1508 DMWARN("%s: reached low water mark for data device: sending event.",
1509 dm_device_name(pool->pool_md));
1510 spin_lock_irq(&pool->lock);
1511 pool->low_water_triggered = true;
1512 spin_unlock_irq(&pool->lock);
1513 dm_table_event(pool->ti->table);
1514 }
1515}
1516
1517static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1518{
1519 int r;
1520 dm_block_t free_blocks;
1521 struct pool *pool = tc->pool;
1522
1523 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1524 return -EINVAL;
1525
1526 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1527 if (r) {
1528 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1529 return r;
1530 }
1531
1532 check_low_water_mark(pool, free_blocks);
1533
1534 if (!free_blocks) {
1535 /*
1536 * Try to commit to see if that will free up some
1537 * more space.
1538 */
1539 r = commit(pool);
1540 if (r)
1541 return r;
1542
1543 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1544 if (r) {
1545 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1546 return r;
1547 }
1548
1549 if (!free_blocks) {
1550 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1551 return -ENOSPC;
1552 }
1553 }
1554
1555 r = dm_pool_alloc_data_block(pool->pmd, result);
1556 if (r) {
1557 if (r == -ENOSPC)
1558 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1559 else
1560 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1561 return r;
1562 }
1563
1564 r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks);
1565 if (r) {
1566 metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r);
1567 return r;
1568 }
1569
1570 if (!free_blocks) {
1571 /* Let's commit before we use up the metadata reserve. */
1572 r = commit(pool);
1573 if (r)
1574 return r;
1575 }
1576
1577 return 0;
1578}
1579
1580/*
1581 * If we have run out of space, queue bios until the device is
1582 * resumed, presumably after having been reloaded with more space.
1583 */
1584static void retry_on_resume(struct bio *bio)
1585{
1586 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1587 struct thin_c *tc = h->tc;
1588
1589 spin_lock_irq(&tc->lock);
1590 bio_list_add(&tc->retry_on_resume_list, bio);
1591 spin_unlock_irq(&tc->lock);
1592}
1593
1594static blk_status_t should_error_unserviceable_bio(struct pool *pool)
1595{
1596 enum pool_mode m = get_pool_mode(pool);
1597
1598 switch (m) {
1599 case PM_WRITE:
1600 /* Shouldn't get here */
1601 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1602 return BLK_STS_IOERR;
1603
1604 case PM_OUT_OF_DATA_SPACE:
1605 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
1606
1607 case PM_OUT_OF_METADATA_SPACE:
1608 case PM_READ_ONLY:
1609 case PM_FAIL:
1610 return BLK_STS_IOERR;
1611 default:
1612 /* Shouldn't get here */
1613 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1614 return BLK_STS_IOERR;
1615 }
1616}
1617
1618static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1619{
1620 blk_status_t error = should_error_unserviceable_bio(pool);
1621
1622 if (error) {
1623 bio->bi_status = error;
1624 bio_endio(bio);
1625 } else
1626 retry_on_resume(bio);
1627}
1628
1629static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1630{
1631 struct bio *bio;
1632 struct bio_list bios;
1633 blk_status_t error;
1634
1635 error = should_error_unserviceable_bio(pool);
1636 if (error) {
1637 cell_error_with_code(pool, cell, error);
1638 return;
1639 }
1640
1641 bio_list_init(&bios);
1642 cell_release(pool, cell, &bios);
1643
1644 while ((bio = bio_list_pop(&bios)))
1645 retry_on_resume(bio);
1646}
1647
1648static void process_discard_cell_no_passdown(struct thin_c *tc,
1649 struct dm_bio_prison_cell *virt_cell)
1650{
1651 struct pool *pool = tc->pool;
1652 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1653
1654 /*
1655 * We don't need to lock the data blocks, since there's no
1656 * passdown. We only lock data blocks for allocation and breaking sharing.
1657 */
1658 m->tc = tc;
1659 m->virt_begin = virt_cell->key.block_begin;
1660 m->virt_end = virt_cell->key.block_end;
1661 m->cell = virt_cell;
1662 m->bio = virt_cell->holder;
1663
1664 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1665 pool->process_prepared_discard(m);
1666}
1667
1668static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1669 struct bio *bio)
1670{
1671 struct pool *pool = tc->pool;
1672
1673 int r;
1674 bool maybe_shared;
1675 struct dm_cell_key data_key;
1676 struct dm_bio_prison_cell *data_cell;
1677 struct dm_thin_new_mapping *m;
1678 dm_block_t virt_begin, virt_end, data_begin, data_end;
1679 dm_block_t len, next_boundary;
1680
1681 while (begin != end) {
1682 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1683 &data_begin, &maybe_shared);
1684 if (r) {
1685 /*
1686 * Silently fail, letting any mappings we've
1687 * created complete.
1688 */
1689 break;
1690 }
1691
1692 data_end = data_begin + (virt_end - virt_begin);
1693
1694 /*
1695 * Make sure the data region obeys the bio prison restrictions.
1696 */
1697 while (data_begin < data_end) {
1698 r = ensure_next_mapping(pool);
1699 if (r)
1700 return; /* we did our best */
1701
1702 next_boundary = ((data_begin >> BIO_PRISON_MAX_RANGE_SHIFT) + 1)
1703 << BIO_PRISON_MAX_RANGE_SHIFT;
1704 len = min_t(sector_t, data_end - data_begin, next_boundary - data_begin);
1705
1706 /* This key is certainly within range given the above splitting */
1707 (void) build_key(tc->td, PHYSICAL, data_begin, data_begin + len, &data_key);
1708 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1709 /* contention, we'll give up with this range */
1710 data_begin += len;
1711 continue;
1712 }
1713
1714 /*
1715 * IO may still be going to the destination block. We must
1716 * quiesce before we can do the removal.
1717 */
1718 m = get_next_mapping(pool);
1719 m->tc = tc;
1720 m->maybe_shared = maybe_shared;
1721 m->virt_begin = virt_begin;
1722 m->virt_end = virt_begin + len;
1723 m->data_block = data_begin;
1724 m->cell = data_cell;
1725 m->bio = bio;
1726
1727 /*
1728 * The parent bio must not complete before sub discard bios are
1729 * chained to it (see end_discard's bio_chain)!
1730 *
1731 * This per-mapping bi_remaining increment is paired with
1732 * the implicit decrement that occurs via bio_endio() in
1733 * end_discard().
1734 */
1735 bio_inc_remaining(bio);
1736 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1737 pool->process_prepared_discard(m);
1738
1739 virt_begin += len;
1740 data_begin += len;
1741 }
1742
1743 begin = virt_end;
1744 }
1745}
1746
1747static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1748{
1749 struct bio *bio = virt_cell->holder;
1750 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1751
1752 /*
1753 * The virt_cell will only get freed once the origin bio completes.
1754 * This means it will remain locked while all the individual
1755 * passdown bios are in flight.
1756 */
1757 h->cell = virt_cell;
1758 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1759
1760 /*
1761 * We complete the bio now, knowing that the bi_remaining field
1762 * will prevent completion until the sub range discards have
1763 * completed.
1764 */
1765 bio_endio(bio);
1766}
1767
1768static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1769{
1770 dm_block_t begin, end;
1771 struct dm_cell_key virt_key;
1772 struct dm_bio_prison_cell *virt_cell;
1773
1774 get_bio_block_range(tc, bio, &begin, &end);
1775 if (begin == end) {
1776 /*
1777 * The discard covers less than a block.
1778 */
1779 bio_endio(bio);
1780 return;
1781 }
1782
1783 if (unlikely(!build_key(tc->td, VIRTUAL, begin, end, &virt_key))) {
1784 DMERR_LIMIT("Discard doesn't respect bio prison limits");
1785 bio_endio(bio);
1786 return;
1787 }
1788
1789 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) {
1790 /*
1791 * Potential starvation issue: We're relying on the
1792 * fs/application being well behaved, and not trying to
1793 * send IO to a region at the same time as discarding it.
1794 * If they do this persistently then it's possible this
1795 * cell will never be granted.
1796 */
1797 return;
1798 }
1799
1800 tc->pool->process_discard_cell(tc, virt_cell);
1801}
1802
1803static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1804 struct dm_cell_key *key,
1805 struct dm_thin_lookup_result *lookup_result,
1806 struct dm_bio_prison_cell *cell)
1807{
1808 int r;
1809 dm_block_t data_block;
1810 struct pool *pool = tc->pool;
1811
1812 r = alloc_data_block(tc, &data_block);
1813 switch (r) {
1814 case 0:
1815 schedule_internal_copy(tc, block, lookup_result->block,
1816 data_block, cell, bio);
1817 break;
1818
1819 case -ENOSPC:
1820 retry_bios_on_resume(pool, cell);
1821 break;
1822
1823 default:
1824 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1825 __func__, r);
1826 cell_error(pool, cell);
1827 break;
1828 }
1829}
1830
1831static void __remap_and_issue_shared_cell(void *context,
1832 struct dm_bio_prison_cell *cell)
1833{
1834 struct remap_info *info = context;
1835 struct bio *bio;
1836
1837 while ((bio = bio_list_pop(&cell->bios))) {
1838 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
1839 bio_op(bio) == REQ_OP_DISCARD)
1840 bio_list_add(&info->defer_bios, bio);
1841 else {
1842 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1843
1844 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1845 inc_all_io_entry(info->tc->pool, bio);
1846 bio_list_add(&info->issue_bios, bio);
1847 }
1848 }
1849}
1850
1851static void remap_and_issue_shared_cell(struct thin_c *tc,
1852 struct dm_bio_prison_cell *cell,
1853 dm_block_t block)
1854{
1855 struct bio *bio;
1856 struct remap_info info;
1857
1858 info.tc = tc;
1859 bio_list_init(&info.defer_bios);
1860 bio_list_init(&info.issue_bios);
1861
1862 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1863 &info, cell);
1864
1865 while ((bio = bio_list_pop(&info.defer_bios)))
1866 thin_defer_bio(tc, bio);
1867
1868 while ((bio = bio_list_pop(&info.issue_bios)))
1869 remap_and_issue(tc, bio, block);
1870}
1871
1872static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1873 dm_block_t block,
1874 struct dm_thin_lookup_result *lookup_result,
1875 struct dm_bio_prison_cell *virt_cell)
1876{
1877 struct dm_bio_prison_cell *data_cell;
1878 struct pool *pool = tc->pool;
1879 struct dm_cell_key key;
1880
1881 /*
1882 * If cell is already occupied, then sharing is already in the process
1883 * of being broken so we have nothing further to do here.
1884 */
1885 build_data_key(tc->td, lookup_result->block, &key);
1886 if (bio_detain(pool, &key, bio, &data_cell)) {
1887 cell_defer_no_holder(tc, virt_cell);
1888 return;
1889 }
1890
1891 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1892 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1893 cell_defer_no_holder(tc, virt_cell);
1894 } else {
1895 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1896
1897 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1898 inc_all_io_entry(pool, bio);
1899 remap_and_issue(tc, bio, lookup_result->block);
1900
1901 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1902 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1903 }
1904}
1905
1906static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1907 struct dm_bio_prison_cell *cell)
1908{
1909 int r;
1910 dm_block_t data_block;
1911 struct pool *pool = tc->pool;
1912
1913 /*
1914 * Remap empty bios (flushes) immediately, without provisioning.
1915 */
1916 if (!bio->bi_iter.bi_size) {
1917 inc_all_io_entry(pool, bio);
1918 cell_defer_no_holder(tc, cell);
1919
1920 remap_and_issue(tc, bio, 0);
1921 return;
1922 }
1923
1924 /*
1925 * Fill read bios with zeroes and complete them immediately.
1926 */
1927 if (bio_data_dir(bio) == READ) {
1928 zero_fill_bio(bio);
1929 cell_defer_no_holder(tc, cell);
1930 bio_endio(bio);
1931 return;
1932 }
1933
1934 r = alloc_data_block(tc, &data_block);
1935 switch (r) {
1936 case 0:
1937 if (tc->origin_dev)
1938 schedule_external_copy(tc, block, data_block, cell, bio);
1939 else
1940 schedule_zero(tc, block, data_block, cell, bio);
1941 break;
1942
1943 case -ENOSPC:
1944 retry_bios_on_resume(pool, cell);
1945 break;
1946
1947 default:
1948 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1949 __func__, r);
1950 cell_error(pool, cell);
1951 break;
1952 }
1953}
1954
1955static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1956{
1957 int r;
1958 struct pool *pool = tc->pool;
1959 struct bio *bio = cell->holder;
1960 dm_block_t block = get_bio_block(tc, bio);
1961 struct dm_thin_lookup_result lookup_result;
1962
1963 if (tc->requeue_mode) {
1964 cell_requeue(pool, cell);
1965 return;
1966 }
1967
1968 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1969 switch (r) {
1970 case 0:
1971 if (lookup_result.shared)
1972 process_shared_bio(tc, bio, block, &lookup_result, cell);
1973 else {
1974 inc_all_io_entry(pool, bio);
1975 remap_and_issue(tc, bio, lookup_result.block);
1976 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1977 }
1978 break;
1979
1980 case -ENODATA:
1981 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1982 inc_all_io_entry(pool, bio);
1983 cell_defer_no_holder(tc, cell);
1984
1985 if (bio_end_sector(bio) <= tc->origin_size)
1986 remap_to_origin_and_issue(tc, bio);
1987
1988 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1989 zero_fill_bio(bio);
1990 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1991 remap_to_origin_and_issue(tc, bio);
1992
1993 } else {
1994 zero_fill_bio(bio);
1995 bio_endio(bio);
1996 }
1997 } else
1998 provision_block(tc, bio, block, cell);
1999 break;
2000
2001 default:
2002 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2003 __func__, r);
2004 cell_defer_no_holder(tc, cell);
2005 bio_io_error(bio);
2006 break;
2007 }
2008}
2009
2010static void process_bio(struct thin_c *tc, struct bio *bio)
2011{
2012 struct pool *pool = tc->pool;
2013 dm_block_t block = get_bio_block(tc, bio);
2014 struct dm_bio_prison_cell *cell;
2015 struct dm_cell_key key;
2016
2017 /*
2018 * If cell is already occupied, then the block is already
2019 * being provisioned so we have nothing further to do here.
2020 */
2021 build_virtual_key(tc->td, block, &key);
2022 if (bio_detain(pool, &key, bio, &cell))
2023 return;
2024
2025 process_cell(tc, cell);
2026}
2027
2028static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
2029 struct dm_bio_prison_cell *cell)
2030{
2031 int r;
2032 int rw = bio_data_dir(bio);
2033 dm_block_t block = get_bio_block(tc, bio);
2034 struct dm_thin_lookup_result lookup_result;
2035
2036 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
2037 switch (r) {
2038 case 0:
2039 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
2040 handle_unserviceable_bio(tc->pool, bio);
2041 if (cell)
2042 cell_defer_no_holder(tc, cell);
2043 } else {
2044 inc_all_io_entry(tc->pool, bio);
2045 remap_and_issue(tc, bio, lookup_result.block);
2046 if (cell)
2047 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
2048 }
2049 break;
2050
2051 case -ENODATA:
2052 if (cell)
2053 cell_defer_no_holder(tc, cell);
2054 if (rw != READ) {
2055 handle_unserviceable_bio(tc->pool, bio);
2056 break;
2057 }
2058
2059 if (tc->origin_dev) {
2060 inc_all_io_entry(tc->pool, bio);
2061 remap_to_origin_and_issue(tc, bio);
2062 break;
2063 }
2064
2065 zero_fill_bio(bio);
2066 bio_endio(bio);
2067 break;
2068
2069 default:
2070 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2071 __func__, r);
2072 if (cell)
2073 cell_defer_no_holder(tc, cell);
2074 bio_io_error(bio);
2075 break;
2076 }
2077}
2078
2079static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
2080{
2081 __process_bio_read_only(tc, bio, NULL);
2082}
2083
2084static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2085{
2086 __process_bio_read_only(tc, cell->holder, cell);
2087}
2088
2089static void process_bio_success(struct thin_c *tc, struct bio *bio)
2090{
2091 bio_endio(bio);
2092}
2093
2094static void process_bio_fail(struct thin_c *tc, struct bio *bio)
2095{
2096 bio_io_error(bio);
2097}
2098
2099static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2100{
2101 cell_success(tc->pool, cell);
2102}
2103
2104static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2105{
2106 cell_error(tc->pool, cell);
2107}
2108
2109/*
2110 * FIXME: should we also commit due to size of transaction, measured in
2111 * metadata blocks?
2112 */
2113static int need_commit_due_to_time(struct pool *pool)
2114{
2115 return !time_in_range(jiffies, pool->last_commit_jiffies,
2116 pool->last_commit_jiffies + COMMIT_PERIOD);
2117}
2118
2119#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2120#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2121
2122static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2123{
2124 struct rb_node **rbp, *parent;
2125 struct dm_thin_endio_hook *pbd;
2126 sector_t bi_sector = bio->bi_iter.bi_sector;
2127
2128 rbp = &tc->sort_bio_list.rb_node;
2129 parent = NULL;
2130 while (*rbp) {
2131 parent = *rbp;
2132 pbd = thin_pbd(parent);
2133
2134 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2135 rbp = &(*rbp)->rb_left;
2136 else
2137 rbp = &(*rbp)->rb_right;
2138 }
2139
2140 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2141 rb_link_node(&pbd->rb_node, parent, rbp);
2142 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2143}
2144
2145static void __extract_sorted_bios(struct thin_c *tc)
2146{
2147 struct rb_node *node;
2148 struct dm_thin_endio_hook *pbd;
2149 struct bio *bio;
2150
2151 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2152 pbd = thin_pbd(node);
2153 bio = thin_bio(pbd);
2154
2155 bio_list_add(&tc->deferred_bio_list, bio);
2156 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2157 }
2158
2159 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2160}
2161
2162static void __sort_thin_deferred_bios(struct thin_c *tc)
2163{
2164 struct bio *bio;
2165 struct bio_list bios;
2166
2167 bio_list_init(&bios);
2168 bio_list_merge(&bios, &tc->deferred_bio_list);
2169 bio_list_init(&tc->deferred_bio_list);
2170
2171 /* Sort deferred_bio_list using rb-tree */
2172 while ((bio = bio_list_pop(&bios)))
2173 __thin_bio_rb_add(tc, bio);
2174
2175 /*
2176 * Transfer the sorted bios in sort_bio_list back to
2177 * deferred_bio_list to allow lockless submission of
2178 * all bios.
2179 */
2180 __extract_sorted_bios(tc);
2181}
2182
2183static void process_thin_deferred_bios(struct thin_c *tc)
2184{
2185 struct pool *pool = tc->pool;
2186 struct bio *bio;
2187 struct bio_list bios;
2188 struct blk_plug plug;
2189 unsigned int count = 0;
2190
2191 if (tc->requeue_mode) {
2192 error_thin_bio_list(tc, &tc->deferred_bio_list,
2193 BLK_STS_DM_REQUEUE);
2194 return;
2195 }
2196
2197 bio_list_init(&bios);
2198
2199 spin_lock_irq(&tc->lock);
2200
2201 if (bio_list_empty(&tc->deferred_bio_list)) {
2202 spin_unlock_irq(&tc->lock);
2203 return;
2204 }
2205
2206 __sort_thin_deferred_bios(tc);
2207
2208 bio_list_merge(&bios, &tc->deferred_bio_list);
2209 bio_list_init(&tc->deferred_bio_list);
2210
2211 spin_unlock_irq(&tc->lock);
2212
2213 blk_start_plug(&plug);
2214 while ((bio = bio_list_pop(&bios))) {
2215 /*
2216 * If we've got no free new_mapping structs, and processing
2217 * this bio might require one, we pause until there are some
2218 * prepared mappings to process.
2219 */
2220 if (ensure_next_mapping(pool)) {
2221 spin_lock_irq(&tc->lock);
2222 bio_list_add(&tc->deferred_bio_list, bio);
2223 bio_list_merge(&tc->deferred_bio_list, &bios);
2224 spin_unlock_irq(&tc->lock);
2225 break;
2226 }
2227
2228 if (bio_op(bio) == REQ_OP_DISCARD)
2229 pool->process_discard(tc, bio);
2230 else
2231 pool->process_bio(tc, bio);
2232
2233 if ((count++ & 127) == 0) {
2234 throttle_work_update(&pool->throttle);
2235 dm_pool_issue_prefetches(pool->pmd);
2236 }
2237 cond_resched();
2238 }
2239 blk_finish_plug(&plug);
2240}
2241
2242static int cmp_cells(const void *lhs, const void *rhs)
2243{
2244 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2245 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2246
2247 BUG_ON(!lhs_cell->holder);
2248 BUG_ON(!rhs_cell->holder);
2249
2250 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2251 return -1;
2252
2253 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2254 return 1;
2255
2256 return 0;
2257}
2258
2259static unsigned int sort_cells(struct pool *pool, struct list_head *cells)
2260{
2261 unsigned int count = 0;
2262 struct dm_bio_prison_cell *cell, *tmp;
2263
2264 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2265 if (count >= CELL_SORT_ARRAY_SIZE)
2266 break;
2267
2268 pool->cell_sort_array[count++] = cell;
2269 list_del(&cell->user_list);
2270 }
2271
2272 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2273
2274 return count;
2275}
2276
2277static void process_thin_deferred_cells(struct thin_c *tc)
2278{
2279 struct pool *pool = tc->pool;
2280 struct list_head cells;
2281 struct dm_bio_prison_cell *cell;
2282 unsigned int i, j, count;
2283
2284 INIT_LIST_HEAD(&cells);
2285
2286 spin_lock_irq(&tc->lock);
2287 list_splice_init(&tc->deferred_cells, &cells);
2288 spin_unlock_irq(&tc->lock);
2289
2290 if (list_empty(&cells))
2291 return;
2292
2293 do {
2294 count = sort_cells(tc->pool, &cells);
2295
2296 for (i = 0; i < count; i++) {
2297 cell = pool->cell_sort_array[i];
2298 BUG_ON(!cell->holder);
2299
2300 /*
2301 * If we've got no free new_mapping structs, and processing
2302 * this bio might require one, we pause until there are some
2303 * prepared mappings to process.
2304 */
2305 if (ensure_next_mapping(pool)) {
2306 for (j = i; j < count; j++)
2307 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2308
2309 spin_lock_irq(&tc->lock);
2310 list_splice(&cells, &tc->deferred_cells);
2311 spin_unlock_irq(&tc->lock);
2312 return;
2313 }
2314
2315 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2316 pool->process_discard_cell(tc, cell);
2317 else
2318 pool->process_cell(tc, cell);
2319 }
2320 cond_resched();
2321 } while (!list_empty(&cells));
2322}
2323
2324static void thin_get(struct thin_c *tc);
2325static void thin_put(struct thin_c *tc);
2326
2327/*
2328 * We can't hold rcu_read_lock() around code that can block. So we
2329 * find a thin with the rcu lock held; bump a refcount; then drop
2330 * the lock.
2331 */
2332static struct thin_c *get_first_thin(struct pool *pool)
2333{
2334 struct thin_c *tc = NULL;
2335
2336 rcu_read_lock();
2337 if (!list_empty(&pool->active_thins)) {
2338 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
2339 thin_get(tc);
2340 }
2341 rcu_read_unlock();
2342
2343 return tc;
2344}
2345
2346static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2347{
2348 struct thin_c *old_tc = tc;
2349
2350 rcu_read_lock();
2351 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2352 thin_get(tc);
2353 thin_put(old_tc);
2354 rcu_read_unlock();
2355 return tc;
2356 }
2357 thin_put(old_tc);
2358 rcu_read_unlock();
2359
2360 return NULL;
2361}
2362
2363static void process_deferred_bios(struct pool *pool)
2364{
2365 struct bio *bio;
2366 struct bio_list bios, bio_completions;
2367 struct thin_c *tc;
2368
2369 tc = get_first_thin(pool);
2370 while (tc) {
2371 process_thin_deferred_cells(tc);
2372 process_thin_deferred_bios(tc);
2373 tc = get_next_thin(pool, tc);
2374 }
2375
2376 /*
2377 * If there are any deferred flush bios, we must commit the metadata
2378 * before issuing them or signaling their completion.
2379 */
2380 bio_list_init(&bios);
2381 bio_list_init(&bio_completions);
2382
2383 spin_lock_irq(&pool->lock);
2384 bio_list_merge(&bios, &pool->deferred_flush_bios);
2385 bio_list_init(&pool->deferred_flush_bios);
2386
2387 bio_list_merge(&bio_completions, &pool->deferred_flush_completions);
2388 bio_list_init(&pool->deferred_flush_completions);
2389 spin_unlock_irq(&pool->lock);
2390
2391 if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) &&
2392 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2393 return;
2394
2395 if (commit(pool)) {
2396 bio_list_merge(&bios, &bio_completions);
2397
2398 while ((bio = bio_list_pop(&bios)))
2399 bio_io_error(bio);
2400 return;
2401 }
2402 pool->last_commit_jiffies = jiffies;
2403
2404 while ((bio = bio_list_pop(&bio_completions)))
2405 bio_endio(bio);
2406
2407 while ((bio = bio_list_pop(&bios))) {
2408 /*
2409 * The data device was flushed as part of metadata commit,
2410 * so complete redundant flushes immediately.
2411 */
2412 if (bio->bi_opf & REQ_PREFLUSH)
2413 bio_endio(bio);
2414 else
2415 dm_submit_bio_remap(bio, NULL);
2416 }
2417}
2418
2419static void do_worker(struct work_struct *ws)
2420{
2421 struct pool *pool = container_of(ws, struct pool, worker);
2422
2423 throttle_work_start(&pool->throttle);
2424 dm_pool_issue_prefetches(pool->pmd);
2425 throttle_work_update(&pool->throttle);
2426 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2427 throttle_work_update(&pool->throttle);
2428 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2429 throttle_work_update(&pool->throttle);
2430 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2431 throttle_work_update(&pool->throttle);
2432 process_deferred_bios(pool);
2433 throttle_work_complete(&pool->throttle);
2434}
2435
2436/*
2437 * We want to commit periodically so that not too much
2438 * unwritten data builds up.
2439 */
2440static void do_waker(struct work_struct *ws)
2441{
2442 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2443
2444 wake_worker(pool);
2445 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2446}
2447
2448/*
2449 * We're holding onto IO to allow userland time to react. After the
2450 * timeout either the pool will have been resized (and thus back in
2451 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2452 */
2453static void do_no_space_timeout(struct work_struct *ws)
2454{
2455 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2456 no_space_timeout);
2457
2458 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2459 pool->pf.error_if_no_space = true;
2460 notify_of_pool_mode_change(pool);
2461 error_retry_list_with_code(pool, BLK_STS_NOSPC);
2462 }
2463}
2464
2465/*----------------------------------------------------------------*/
2466
2467struct pool_work {
2468 struct work_struct worker;
2469 struct completion complete;
2470};
2471
2472static struct pool_work *to_pool_work(struct work_struct *ws)
2473{
2474 return container_of(ws, struct pool_work, worker);
2475}
2476
2477static void pool_work_complete(struct pool_work *pw)
2478{
2479 complete(&pw->complete);
2480}
2481
2482static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2483 void (*fn)(struct work_struct *))
2484{
2485 INIT_WORK_ONSTACK(&pw->worker, fn);
2486 init_completion(&pw->complete);
2487 queue_work(pool->wq, &pw->worker);
2488 wait_for_completion(&pw->complete);
2489}
2490
2491/*----------------------------------------------------------------*/
2492
2493struct noflush_work {
2494 struct pool_work pw;
2495 struct thin_c *tc;
2496};
2497
2498static struct noflush_work *to_noflush(struct work_struct *ws)
2499{
2500 return container_of(to_pool_work(ws), struct noflush_work, pw);
2501}
2502
2503static void do_noflush_start(struct work_struct *ws)
2504{
2505 struct noflush_work *w = to_noflush(ws);
2506
2507 w->tc->requeue_mode = true;
2508 requeue_io(w->tc);
2509 pool_work_complete(&w->pw);
2510}
2511
2512static void do_noflush_stop(struct work_struct *ws)
2513{
2514 struct noflush_work *w = to_noflush(ws);
2515
2516 w->tc->requeue_mode = false;
2517 pool_work_complete(&w->pw);
2518}
2519
2520static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2521{
2522 struct noflush_work w;
2523
2524 w.tc = tc;
2525 pool_work_wait(&w.pw, tc->pool, fn);
2526}
2527
2528/*----------------------------------------------------------------*/
2529
2530static void set_discard_callbacks(struct pool *pool)
2531{
2532 struct pool_c *pt = pool->ti->private;
2533
2534 if (pt->adjusted_pf.discard_passdown) {
2535 pool->process_discard_cell = process_discard_cell_passdown;
2536 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2537 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2538 } else {
2539 pool->process_discard_cell = process_discard_cell_no_passdown;
2540 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2541 }
2542}
2543
2544static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2545{
2546 struct pool_c *pt = pool->ti->private;
2547 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2548 enum pool_mode old_mode = get_pool_mode(pool);
2549 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
2550
2551 /*
2552 * Never allow the pool to transition to PM_WRITE mode if user
2553 * intervention is required to verify metadata and data consistency.
2554 */
2555 if (new_mode == PM_WRITE && needs_check) {
2556 DMERR("%s: unable to switch pool to write mode until repaired.",
2557 dm_device_name(pool->pool_md));
2558 if (old_mode != new_mode)
2559 new_mode = old_mode;
2560 else
2561 new_mode = PM_READ_ONLY;
2562 }
2563 /*
2564 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2565 * not going to recover without a thin_repair. So we never let the
2566 * pool move out of the old mode.
2567 */
2568 if (old_mode == PM_FAIL)
2569 new_mode = old_mode;
2570
2571 switch (new_mode) {
2572 case PM_FAIL:
2573 dm_pool_metadata_read_only(pool->pmd);
2574 pool->process_bio = process_bio_fail;
2575 pool->process_discard = process_bio_fail;
2576 pool->process_cell = process_cell_fail;
2577 pool->process_discard_cell = process_cell_fail;
2578 pool->process_prepared_mapping = process_prepared_mapping_fail;
2579 pool->process_prepared_discard = process_prepared_discard_fail;
2580
2581 error_retry_list(pool);
2582 break;
2583
2584 case PM_OUT_OF_METADATA_SPACE:
2585 case PM_READ_ONLY:
2586 dm_pool_metadata_read_only(pool->pmd);
2587 pool->process_bio = process_bio_read_only;
2588 pool->process_discard = process_bio_success;
2589 pool->process_cell = process_cell_read_only;
2590 pool->process_discard_cell = process_cell_success;
2591 pool->process_prepared_mapping = process_prepared_mapping_fail;
2592 pool->process_prepared_discard = process_prepared_discard_success;
2593
2594 error_retry_list(pool);
2595 break;
2596
2597 case PM_OUT_OF_DATA_SPACE:
2598 /*
2599 * Ideally we'd never hit this state; the low water mark
2600 * would trigger userland to extend the pool before we
2601 * completely run out of data space. However, many small
2602 * IOs to unprovisioned space can consume data space at an
2603 * alarming rate. Adjust your low water mark if you're
2604 * frequently seeing this mode.
2605 */
2606 pool->out_of_data_space = true;
2607 pool->process_bio = process_bio_read_only;
2608 pool->process_discard = process_discard_bio;
2609 pool->process_cell = process_cell_read_only;
2610 pool->process_prepared_mapping = process_prepared_mapping;
2611 set_discard_callbacks(pool);
2612
2613 if (!pool->pf.error_if_no_space && no_space_timeout)
2614 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2615 break;
2616
2617 case PM_WRITE:
2618 if (old_mode == PM_OUT_OF_DATA_SPACE)
2619 cancel_delayed_work_sync(&pool->no_space_timeout);
2620 pool->out_of_data_space = false;
2621 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2622 dm_pool_metadata_read_write(pool->pmd);
2623 pool->process_bio = process_bio;
2624 pool->process_discard = process_discard_bio;
2625 pool->process_cell = process_cell;
2626 pool->process_prepared_mapping = process_prepared_mapping;
2627 set_discard_callbacks(pool);
2628 break;
2629 }
2630
2631 pool->pf.mode = new_mode;
2632 /*
2633 * The pool mode may have changed, sync it so bind_control_target()
2634 * doesn't cause an unexpected mode transition on resume.
2635 */
2636 pt->adjusted_pf.mode = new_mode;
2637
2638 if (old_mode != new_mode)
2639 notify_of_pool_mode_change(pool);
2640}
2641
2642static void abort_transaction(struct pool *pool)
2643{
2644 const char *dev_name = dm_device_name(pool->pool_md);
2645
2646 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2647 if (dm_pool_abort_metadata(pool->pmd)) {
2648 DMERR("%s: failed to abort metadata transaction", dev_name);
2649 set_pool_mode(pool, PM_FAIL);
2650 }
2651
2652 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2653 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2654 set_pool_mode(pool, PM_FAIL);
2655 }
2656}
2657
2658static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2659{
2660 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2661 dm_device_name(pool->pool_md), op, r);
2662
2663 abort_transaction(pool);
2664 set_pool_mode(pool, PM_READ_ONLY);
2665}
2666
2667/*----------------------------------------------------------------*/
2668
2669/*
2670 * Mapping functions.
2671 */
2672
2673/*
2674 * Called only while mapping a thin bio to hand it over to the workqueue.
2675 */
2676static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2677{
2678 struct pool *pool = tc->pool;
2679
2680 spin_lock_irq(&tc->lock);
2681 bio_list_add(&tc->deferred_bio_list, bio);
2682 spin_unlock_irq(&tc->lock);
2683
2684 wake_worker(pool);
2685}
2686
2687static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2688{
2689 struct pool *pool = tc->pool;
2690
2691 throttle_lock(&pool->throttle);
2692 thin_defer_bio(tc, bio);
2693 throttle_unlock(&pool->throttle);
2694}
2695
2696static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2697{
2698 struct pool *pool = tc->pool;
2699
2700 throttle_lock(&pool->throttle);
2701 spin_lock_irq(&tc->lock);
2702 list_add_tail(&cell->user_list, &tc->deferred_cells);
2703 spin_unlock_irq(&tc->lock);
2704 throttle_unlock(&pool->throttle);
2705
2706 wake_worker(pool);
2707}
2708
2709static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2710{
2711 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2712
2713 h->tc = tc;
2714 h->shared_read_entry = NULL;
2715 h->all_io_entry = NULL;
2716 h->overwrite_mapping = NULL;
2717 h->cell = NULL;
2718}
2719
2720/*
2721 * Non-blocking function called from the thin target's map function.
2722 */
2723static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2724{
2725 int r;
2726 struct thin_c *tc = ti->private;
2727 dm_block_t block = get_bio_block(tc, bio);
2728 struct dm_thin_device *td = tc->td;
2729 struct dm_thin_lookup_result result;
2730 struct dm_bio_prison_cell *virt_cell, *data_cell;
2731 struct dm_cell_key key;
2732
2733 thin_hook_bio(tc, bio);
2734
2735 if (tc->requeue_mode) {
2736 bio->bi_status = BLK_STS_DM_REQUEUE;
2737 bio_endio(bio);
2738 return DM_MAPIO_SUBMITTED;
2739 }
2740
2741 if (get_pool_mode(tc->pool) == PM_FAIL) {
2742 bio_io_error(bio);
2743 return DM_MAPIO_SUBMITTED;
2744 }
2745
2746 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
2747 thin_defer_bio_with_throttle(tc, bio);
2748 return DM_MAPIO_SUBMITTED;
2749 }
2750
2751 /*
2752 * We must hold the virtual cell before doing the lookup, otherwise
2753 * there's a race with discard.
2754 */
2755 build_virtual_key(tc->td, block, &key);
2756 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2757 return DM_MAPIO_SUBMITTED;
2758
2759 r = dm_thin_find_block(td, block, 0, &result);
2760
2761 /*
2762 * Note that we defer readahead too.
2763 */
2764 switch (r) {
2765 case 0:
2766 if (unlikely(result.shared)) {
2767 /*
2768 * We have a race condition here between the
2769 * result.shared value returned by the lookup and
2770 * snapshot creation, which may cause new
2771 * sharing.
2772 *
2773 * To avoid this always quiesce the origin before
2774 * taking the snap. You want to do this anyway to
2775 * ensure a consistent application view
2776 * (i.e. lockfs).
2777 *
2778 * More distant ancestors are irrelevant. The
2779 * shared flag will be set in their case.
2780 */
2781 thin_defer_cell(tc, virt_cell);
2782 return DM_MAPIO_SUBMITTED;
2783 }
2784
2785 build_data_key(tc->td, result.block, &key);
2786 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2787 cell_defer_no_holder(tc, virt_cell);
2788 return DM_MAPIO_SUBMITTED;
2789 }
2790
2791 inc_all_io_entry(tc->pool, bio);
2792 cell_defer_no_holder(tc, data_cell);
2793 cell_defer_no_holder(tc, virt_cell);
2794
2795 remap(tc, bio, result.block);
2796 return DM_MAPIO_REMAPPED;
2797
2798 case -ENODATA:
2799 case -EWOULDBLOCK:
2800 thin_defer_cell(tc, virt_cell);
2801 return DM_MAPIO_SUBMITTED;
2802
2803 default:
2804 /*
2805 * Must always call bio_io_error on failure.
2806 * dm_thin_find_block can fail with -EINVAL if the
2807 * pool is switched to fail-io mode.
2808 */
2809 bio_io_error(bio);
2810 cell_defer_no_holder(tc, virt_cell);
2811 return DM_MAPIO_SUBMITTED;
2812 }
2813}
2814
2815static void requeue_bios(struct pool *pool)
2816{
2817 struct thin_c *tc;
2818
2819 rcu_read_lock();
2820 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2821 spin_lock_irq(&tc->lock);
2822 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2823 bio_list_init(&tc->retry_on_resume_list);
2824 spin_unlock_irq(&tc->lock);
2825 }
2826 rcu_read_unlock();
2827}
2828
2829/*
2830 *--------------------------------------------------------------
2831 * Binding of control targets to a pool object
2832 *--------------------------------------------------------------
2833 */
2834static bool is_factor(sector_t block_size, uint32_t n)
2835{
2836 return !sector_div(block_size, n);
2837}
2838
2839/*
2840 * If discard_passdown was enabled verify that the data device
2841 * supports discards. Disable discard_passdown if not.
2842 */
2843static void disable_discard_passdown_if_not_supported(struct pool_c *pt)
2844{
2845 struct pool *pool = pt->pool;
2846 struct block_device *data_bdev = pt->data_dev->bdev;
2847 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2848 const char *reason = NULL;
2849
2850 if (!pt->adjusted_pf.discard_passdown)
2851 return;
2852
2853 if (!bdev_max_discard_sectors(pt->data_dev->bdev))
2854 reason = "discard unsupported";
2855
2856 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2857 reason = "max discard sectors smaller than a block";
2858
2859 if (reason) {
2860 DMWARN("Data device (%pg) %s: Disabling discard passdown.", data_bdev, reason);
2861 pt->adjusted_pf.discard_passdown = false;
2862 }
2863}
2864
2865static int bind_control_target(struct pool *pool, struct dm_target *ti)
2866{
2867 struct pool_c *pt = ti->private;
2868
2869 /*
2870 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2871 */
2872 enum pool_mode old_mode = get_pool_mode(pool);
2873 enum pool_mode new_mode = pt->adjusted_pf.mode;
2874
2875 /*
2876 * Don't change the pool's mode until set_pool_mode() below.
2877 * Otherwise the pool's process_* function pointers may
2878 * not match the desired pool mode.
2879 */
2880 pt->adjusted_pf.mode = old_mode;
2881
2882 pool->ti = ti;
2883 pool->pf = pt->adjusted_pf;
2884 pool->low_water_blocks = pt->low_water_blocks;
2885
2886 set_pool_mode(pool, new_mode);
2887
2888 return 0;
2889}
2890
2891static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2892{
2893 if (pool->ti == ti)
2894 pool->ti = NULL;
2895}
2896
2897/*
2898 *--------------------------------------------------------------
2899 * Pool creation
2900 *--------------------------------------------------------------
2901 */
2902/* Initialize pool features. */
2903static void pool_features_init(struct pool_features *pf)
2904{
2905 pf->mode = PM_WRITE;
2906 pf->zero_new_blocks = true;
2907 pf->discard_enabled = true;
2908 pf->discard_passdown = true;
2909 pf->error_if_no_space = false;
2910}
2911
2912static void __pool_destroy(struct pool *pool)
2913{
2914 __pool_table_remove(pool);
2915
2916 vfree(pool->cell_sort_array);
2917 if (dm_pool_metadata_close(pool->pmd) < 0)
2918 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2919
2920 dm_bio_prison_destroy(pool->prison);
2921 dm_kcopyd_client_destroy(pool->copier);
2922
2923 cancel_delayed_work_sync(&pool->waker);
2924 cancel_delayed_work_sync(&pool->no_space_timeout);
2925 if (pool->wq)
2926 destroy_workqueue(pool->wq);
2927
2928 if (pool->next_mapping)
2929 mempool_free(pool->next_mapping, &pool->mapping_pool);
2930 mempool_exit(&pool->mapping_pool);
2931 dm_deferred_set_destroy(pool->shared_read_ds);
2932 dm_deferred_set_destroy(pool->all_io_ds);
2933 kfree(pool);
2934}
2935
2936static struct kmem_cache *_new_mapping_cache;
2937
2938static struct pool *pool_create(struct mapped_device *pool_md,
2939 struct block_device *metadata_dev,
2940 struct block_device *data_dev,
2941 unsigned long block_size,
2942 int read_only, char **error)
2943{
2944 int r;
2945 void *err_p;
2946 struct pool *pool;
2947 struct dm_pool_metadata *pmd;
2948 bool format_device = read_only ? false : true;
2949
2950 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2951 if (IS_ERR(pmd)) {
2952 *error = "Error creating metadata object";
2953 return (struct pool *)pmd;
2954 }
2955
2956 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
2957 if (!pool) {
2958 *error = "Error allocating memory for pool";
2959 err_p = ERR_PTR(-ENOMEM);
2960 goto bad_pool;
2961 }
2962
2963 pool->pmd = pmd;
2964 pool->sectors_per_block = block_size;
2965 if (block_size & (block_size - 1))
2966 pool->sectors_per_block_shift = -1;
2967 else
2968 pool->sectors_per_block_shift = __ffs(block_size);
2969 pool->low_water_blocks = 0;
2970 pool_features_init(&pool->pf);
2971 pool->prison = dm_bio_prison_create();
2972 if (!pool->prison) {
2973 *error = "Error creating pool's bio prison";
2974 err_p = ERR_PTR(-ENOMEM);
2975 goto bad_prison;
2976 }
2977
2978 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2979 if (IS_ERR(pool->copier)) {
2980 r = PTR_ERR(pool->copier);
2981 *error = "Error creating pool's kcopyd client";
2982 err_p = ERR_PTR(r);
2983 goto bad_kcopyd_client;
2984 }
2985
2986 /*
2987 * Create singlethreaded workqueue that will service all devices
2988 * that use this metadata.
2989 */
2990 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2991 if (!pool->wq) {
2992 *error = "Error creating pool's workqueue";
2993 err_p = ERR_PTR(-ENOMEM);
2994 goto bad_wq;
2995 }
2996
2997 throttle_init(&pool->throttle);
2998 INIT_WORK(&pool->worker, do_worker);
2999 INIT_DELAYED_WORK(&pool->waker, do_waker);
3000 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
3001 spin_lock_init(&pool->lock);
3002 bio_list_init(&pool->deferred_flush_bios);
3003 bio_list_init(&pool->deferred_flush_completions);
3004 INIT_LIST_HEAD(&pool->prepared_mappings);
3005 INIT_LIST_HEAD(&pool->prepared_discards);
3006 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
3007 INIT_LIST_HEAD(&pool->active_thins);
3008 pool->low_water_triggered = false;
3009 pool->suspended = true;
3010 pool->out_of_data_space = false;
3011
3012 pool->shared_read_ds = dm_deferred_set_create();
3013 if (!pool->shared_read_ds) {
3014 *error = "Error creating pool's shared read deferred set";
3015 err_p = ERR_PTR(-ENOMEM);
3016 goto bad_shared_read_ds;
3017 }
3018
3019 pool->all_io_ds = dm_deferred_set_create();
3020 if (!pool->all_io_ds) {
3021 *error = "Error creating pool's all io deferred set";
3022 err_p = ERR_PTR(-ENOMEM);
3023 goto bad_all_io_ds;
3024 }
3025
3026 pool->next_mapping = NULL;
3027 r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE,
3028 _new_mapping_cache);
3029 if (r) {
3030 *error = "Error creating pool's mapping mempool";
3031 err_p = ERR_PTR(r);
3032 goto bad_mapping_pool;
3033 }
3034
3035 pool->cell_sort_array =
3036 vmalloc(array_size(CELL_SORT_ARRAY_SIZE,
3037 sizeof(*pool->cell_sort_array)));
3038 if (!pool->cell_sort_array) {
3039 *error = "Error allocating cell sort array";
3040 err_p = ERR_PTR(-ENOMEM);
3041 goto bad_sort_array;
3042 }
3043
3044 pool->ref_count = 1;
3045 pool->last_commit_jiffies = jiffies;
3046 pool->pool_md = pool_md;
3047 pool->md_dev = metadata_dev;
3048 pool->data_dev = data_dev;
3049 __pool_table_insert(pool);
3050
3051 return pool;
3052
3053bad_sort_array:
3054 mempool_exit(&pool->mapping_pool);
3055bad_mapping_pool:
3056 dm_deferred_set_destroy(pool->all_io_ds);
3057bad_all_io_ds:
3058 dm_deferred_set_destroy(pool->shared_read_ds);
3059bad_shared_read_ds:
3060 destroy_workqueue(pool->wq);
3061bad_wq:
3062 dm_kcopyd_client_destroy(pool->copier);
3063bad_kcopyd_client:
3064 dm_bio_prison_destroy(pool->prison);
3065bad_prison:
3066 kfree(pool);
3067bad_pool:
3068 if (dm_pool_metadata_close(pmd))
3069 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
3070
3071 return err_p;
3072}
3073
3074static void __pool_inc(struct pool *pool)
3075{
3076 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3077 pool->ref_count++;
3078}
3079
3080static void __pool_dec(struct pool *pool)
3081{
3082 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3083 BUG_ON(!pool->ref_count);
3084 if (!--pool->ref_count)
3085 __pool_destroy(pool);
3086}
3087
3088static struct pool *__pool_find(struct mapped_device *pool_md,
3089 struct block_device *metadata_dev,
3090 struct block_device *data_dev,
3091 unsigned long block_size, int read_only,
3092 char **error, int *created)
3093{
3094 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
3095
3096 if (pool) {
3097 if (pool->pool_md != pool_md) {
3098 *error = "metadata device already in use by a pool";
3099 return ERR_PTR(-EBUSY);
3100 }
3101 if (pool->data_dev != data_dev) {
3102 *error = "data device already in use by a pool";
3103 return ERR_PTR(-EBUSY);
3104 }
3105 __pool_inc(pool);
3106
3107 } else {
3108 pool = __pool_table_lookup(pool_md);
3109 if (pool) {
3110 if (pool->md_dev != metadata_dev || pool->data_dev != data_dev) {
3111 *error = "different pool cannot replace a pool";
3112 return ERR_PTR(-EINVAL);
3113 }
3114 __pool_inc(pool);
3115
3116 } else {
3117 pool = pool_create(pool_md, metadata_dev, data_dev, block_size, read_only, error);
3118 *created = 1;
3119 }
3120 }
3121
3122 return pool;
3123}
3124
3125/*
3126 *--------------------------------------------------------------
3127 * Pool target methods
3128 *--------------------------------------------------------------
3129 */
3130static void pool_dtr(struct dm_target *ti)
3131{
3132 struct pool_c *pt = ti->private;
3133
3134 mutex_lock(&dm_thin_pool_table.mutex);
3135
3136 unbind_control_target(pt->pool, ti);
3137 __pool_dec(pt->pool);
3138 dm_put_device(ti, pt->metadata_dev);
3139 dm_put_device(ti, pt->data_dev);
3140 kfree(pt);
3141
3142 mutex_unlock(&dm_thin_pool_table.mutex);
3143}
3144
3145static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3146 struct dm_target *ti)
3147{
3148 int r;
3149 unsigned int argc;
3150 const char *arg_name;
3151
3152 static const struct dm_arg _args[] = {
3153 {0, 4, "Invalid number of pool feature arguments"},
3154 };
3155
3156 /*
3157 * No feature arguments supplied.
3158 */
3159 if (!as->argc)
3160 return 0;
3161
3162 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3163 if (r)
3164 return -EINVAL;
3165
3166 while (argc && !r) {
3167 arg_name = dm_shift_arg(as);
3168 argc--;
3169
3170 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3171 pf->zero_new_blocks = false;
3172
3173 else if (!strcasecmp(arg_name, "ignore_discard"))
3174 pf->discard_enabled = false;
3175
3176 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3177 pf->discard_passdown = false;
3178
3179 else if (!strcasecmp(arg_name, "read_only"))
3180 pf->mode = PM_READ_ONLY;
3181
3182 else if (!strcasecmp(arg_name, "error_if_no_space"))
3183 pf->error_if_no_space = true;
3184
3185 else {
3186 ti->error = "Unrecognised pool feature requested";
3187 r = -EINVAL;
3188 break;
3189 }
3190 }
3191
3192 return r;
3193}
3194
3195static void metadata_low_callback(void *context)
3196{
3197 struct pool *pool = context;
3198
3199 DMWARN("%s: reached low water mark for metadata device: sending event.",
3200 dm_device_name(pool->pool_md));
3201
3202 dm_table_event(pool->ti->table);
3203}
3204
3205/*
3206 * We need to flush the data device **before** committing the metadata.
3207 *
3208 * This ensures that the data blocks of any newly inserted mappings are
3209 * properly written to non-volatile storage and won't be lost in case of a
3210 * crash.
3211 *
3212 * Failure to do so can result in data corruption in the case of internal or
3213 * external snapshots and in the case of newly provisioned blocks, when block
3214 * zeroing is enabled.
3215 */
3216static int metadata_pre_commit_callback(void *context)
3217{
3218 struct pool *pool = context;
3219
3220 return blkdev_issue_flush(pool->data_dev);
3221}
3222
3223static sector_t get_dev_size(struct block_device *bdev)
3224{
3225 return bdev_nr_sectors(bdev);
3226}
3227
3228static void warn_if_metadata_device_too_big(struct block_device *bdev)
3229{
3230 sector_t metadata_dev_size = get_dev_size(bdev);
3231
3232 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3233 DMWARN("Metadata device %pg is larger than %u sectors: excess space will not be used.",
3234 bdev, THIN_METADATA_MAX_SECTORS);
3235}
3236
3237static sector_t get_metadata_dev_size(struct block_device *bdev)
3238{
3239 sector_t metadata_dev_size = get_dev_size(bdev);
3240
3241 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3242 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3243
3244 return metadata_dev_size;
3245}
3246
3247static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3248{
3249 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3250
3251 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3252
3253 return metadata_dev_size;
3254}
3255
3256/*
3257 * When a metadata threshold is crossed a dm event is triggered, and
3258 * userland should respond by growing the metadata device. We could let
3259 * userland set the threshold, like we do with the data threshold, but I'm
3260 * not sure they know enough to do this well.
3261 */
3262static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3263{
3264 /*
3265 * 4M is ample for all ops with the possible exception of thin
3266 * device deletion which is harmless if it fails (just retry the
3267 * delete after you've grown the device).
3268 */
3269 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3270
3271 return min((dm_block_t)1024ULL /* 4M */, quarter);
3272}
3273
3274/*
3275 * thin-pool <metadata dev> <data dev>
3276 * <data block size (sectors)>
3277 * <low water mark (blocks)>
3278 * [<#feature args> [<arg>]*]
3279 *
3280 * Optional feature arguments are:
3281 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3282 * ignore_discard: disable discard
3283 * no_discard_passdown: don't pass discards down to the data device
3284 * read_only: Don't allow any changes to be made to the pool metadata.
3285 * error_if_no_space: error IOs, instead of queueing, if no space.
3286 */
3287static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3288{
3289 int r, pool_created = 0;
3290 struct pool_c *pt;
3291 struct pool *pool;
3292 struct pool_features pf;
3293 struct dm_arg_set as;
3294 struct dm_dev *data_dev;
3295 unsigned long block_size;
3296 dm_block_t low_water_blocks;
3297 struct dm_dev *metadata_dev;
3298 blk_mode_t metadata_mode;
3299
3300 /*
3301 * FIXME Remove validation from scope of lock.
3302 */
3303 mutex_lock(&dm_thin_pool_table.mutex);
3304
3305 if (argc < 4) {
3306 ti->error = "Invalid argument count";
3307 r = -EINVAL;
3308 goto out_unlock;
3309 }
3310
3311 as.argc = argc;
3312 as.argv = argv;
3313
3314 /* make sure metadata and data are different devices */
3315 if (!strcmp(argv[0], argv[1])) {
3316 ti->error = "Error setting metadata or data device";
3317 r = -EINVAL;
3318 goto out_unlock;
3319 }
3320
3321 /*
3322 * Set default pool features.
3323 */
3324 pool_features_init(&pf);
3325
3326 dm_consume_args(&as, 4);
3327 r = parse_pool_features(&as, &pf, ti);
3328 if (r)
3329 goto out_unlock;
3330
3331 metadata_mode = BLK_OPEN_READ |
3332 ((pf.mode == PM_READ_ONLY) ? 0 : BLK_OPEN_WRITE);
3333 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3334 if (r) {
3335 ti->error = "Error opening metadata block device";
3336 goto out_unlock;
3337 }
3338 warn_if_metadata_device_too_big(metadata_dev->bdev);
3339
3340 r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE, &data_dev);
3341 if (r) {
3342 ti->error = "Error getting data device";
3343 goto out_metadata;
3344 }
3345
3346 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3347 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3348 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3349 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3350 ti->error = "Invalid block size";
3351 r = -EINVAL;
3352 goto out;
3353 }
3354
3355 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3356 ti->error = "Invalid low water mark";
3357 r = -EINVAL;
3358 goto out;
3359 }
3360
3361 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3362 if (!pt) {
3363 r = -ENOMEM;
3364 goto out;
3365 }
3366
3367 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, data_dev->bdev,
3368 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3369 if (IS_ERR(pool)) {
3370 r = PTR_ERR(pool);
3371 goto out_free_pt;
3372 }
3373
3374 /*
3375 * 'pool_created' reflects whether this is the first table load.
3376 * Top level discard support is not allowed to be changed after
3377 * initial load. This would require a pool reload to trigger thin
3378 * device changes.
3379 */
3380 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3381 ti->error = "Discard support cannot be disabled once enabled";
3382 r = -EINVAL;
3383 goto out_flags_changed;
3384 }
3385
3386 pt->pool = pool;
3387 pt->ti = ti;
3388 pt->metadata_dev = metadata_dev;
3389 pt->data_dev = data_dev;
3390 pt->low_water_blocks = low_water_blocks;
3391 pt->adjusted_pf = pt->requested_pf = pf;
3392 ti->num_flush_bios = 1;
3393 ti->limit_swap_bios = true;
3394
3395 /*
3396 * Only need to enable discards if the pool should pass
3397 * them down to the data device. The thin device's discard
3398 * processing will cause mappings to be removed from the btree.
3399 */
3400 if (pf.discard_enabled && pf.discard_passdown) {
3401 ti->num_discard_bios = 1;
3402 /*
3403 * Setting 'discards_supported' circumvents the normal
3404 * stacking of discard limits (this keeps the pool and
3405 * thin devices' discard limits consistent).
3406 */
3407 ti->discards_supported = true;
3408 ti->max_discard_granularity = true;
3409 }
3410 ti->private = pt;
3411
3412 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
3413 calc_metadata_threshold(pt),
3414 metadata_low_callback,
3415 pool);
3416 if (r) {
3417 ti->error = "Error registering metadata threshold";
3418 goto out_flags_changed;
3419 }
3420
3421 dm_pool_register_pre_commit_callback(pool->pmd,
3422 metadata_pre_commit_callback, pool);
3423
3424 mutex_unlock(&dm_thin_pool_table.mutex);
3425
3426 return 0;
3427
3428out_flags_changed:
3429 __pool_dec(pool);
3430out_free_pt:
3431 kfree(pt);
3432out:
3433 dm_put_device(ti, data_dev);
3434out_metadata:
3435 dm_put_device(ti, metadata_dev);
3436out_unlock:
3437 mutex_unlock(&dm_thin_pool_table.mutex);
3438
3439 return r;
3440}
3441
3442static int pool_map(struct dm_target *ti, struct bio *bio)
3443{
3444 struct pool_c *pt = ti->private;
3445 struct pool *pool = pt->pool;
3446
3447 /*
3448 * As this is a singleton target, ti->begin is always zero.
3449 */
3450 spin_lock_irq(&pool->lock);
3451 bio_set_dev(bio, pt->data_dev->bdev);
3452 spin_unlock_irq(&pool->lock);
3453
3454 return DM_MAPIO_REMAPPED;
3455}
3456
3457static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
3458{
3459 int r;
3460 struct pool_c *pt = ti->private;
3461 struct pool *pool = pt->pool;
3462 sector_t data_size = ti->len;
3463 dm_block_t sb_data_size;
3464
3465 *need_commit = false;
3466
3467 (void) sector_div(data_size, pool->sectors_per_block);
3468
3469 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
3470 if (r) {
3471 DMERR("%s: failed to retrieve data device size",
3472 dm_device_name(pool->pool_md));
3473 return r;
3474 }
3475
3476 if (data_size < sb_data_size) {
3477 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3478 dm_device_name(pool->pool_md),
3479 (unsigned long long)data_size, sb_data_size);
3480 return -EINVAL;
3481
3482 } else if (data_size > sb_data_size) {
3483 if (dm_pool_metadata_needs_check(pool->pmd)) {
3484 DMERR("%s: unable to grow the data device until repaired.",
3485 dm_device_name(pool->pool_md));
3486 return 0;
3487 }
3488
3489 if (sb_data_size)
3490 DMINFO("%s: growing the data device from %llu to %llu blocks",
3491 dm_device_name(pool->pool_md),
3492 sb_data_size, (unsigned long long)data_size);
3493 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3494 if (r) {
3495 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3496 return r;
3497 }
3498
3499 *need_commit = true;
3500 }
3501
3502 return 0;
3503}
3504
3505static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3506{
3507 int r;
3508 struct pool_c *pt = ti->private;
3509 struct pool *pool = pt->pool;
3510 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3511
3512 *need_commit = false;
3513
3514 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3515
3516 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3517 if (r) {
3518 DMERR("%s: failed to retrieve metadata device size",
3519 dm_device_name(pool->pool_md));
3520 return r;
3521 }
3522
3523 if (metadata_dev_size < sb_metadata_dev_size) {
3524 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3525 dm_device_name(pool->pool_md),
3526 metadata_dev_size, sb_metadata_dev_size);
3527 return -EINVAL;
3528
3529 } else if (metadata_dev_size > sb_metadata_dev_size) {
3530 if (dm_pool_metadata_needs_check(pool->pmd)) {
3531 DMERR("%s: unable to grow the metadata device until repaired.",
3532 dm_device_name(pool->pool_md));
3533 return 0;
3534 }
3535
3536 warn_if_metadata_device_too_big(pool->md_dev);
3537 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3538 dm_device_name(pool->pool_md),
3539 sb_metadata_dev_size, metadata_dev_size);
3540
3541 if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE)
3542 set_pool_mode(pool, PM_WRITE);
3543
3544 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3545 if (r) {
3546 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3547 return r;
3548 }
3549
3550 *need_commit = true;
3551 }
3552
3553 return 0;
3554}
3555
3556/*
3557 * Retrieves the number of blocks of the data device from
3558 * the superblock and compares it to the actual device size,
3559 * thus resizing the data device in case it has grown.
3560 *
3561 * This both copes with opening preallocated data devices in the ctr
3562 * being followed by a resume
3563 * -and-
3564 * calling the resume method individually after userspace has
3565 * grown the data device in reaction to a table event.
3566 */
3567static int pool_preresume(struct dm_target *ti)
3568{
3569 int r;
3570 bool need_commit1, need_commit2;
3571 struct pool_c *pt = ti->private;
3572 struct pool *pool = pt->pool;
3573
3574 /*
3575 * Take control of the pool object.
3576 */
3577 r = bind_control_target(pool, ti);
3578 if (r)
3579 goto out;
3580
3581 r = maybe_resize_data_dev(ti, &need_commit1);
3582 if (r)
3583 goto out;
3584
3585 r = maybe_resize_metadata_dev(ti, &need_commit2);
3586 if (r)
3587 goto out;
3588
3589 if (need_commit1 || need_commit2)
3590 (void) commit(pool);
3591out:
3592 /*
3593 * When a thin-pool is PM_FAIL, it cannot be rebuilt if
3594 * bio is in deferred list. Therefore need to return 0
3595 * to allow pool_resume() to flush IO.
3596 */
3597 if (r && get_pool_mode(pool) == PM_FAIL)
3598 r = 0;
3599
3600 return r;
3601}
3602
3603static void pool_suspend_active_thins(struct pool *pool)
3604{
3605 struct thin_c *tc;
3606
3607 /* Suspend all active thin devices */
3608 tc = get_first_thin(pool);
3609 while (tc) {
3610 dm_internal_suspend_noflush(tc->thin_md);
3611 tc = get_next_thin(pool, tc);
3612 }
3613}
3614
3615static void pool_resume_active_thins(struct pool *pool)
3616{
3617 struct thin_c *tc;
3618
3619 /* Resume all active thin devices */
3620 tc = get_first_thin(pool);
3621 while (tc) {
3622 dm_internal_resume(tc->thin_md);
3623 tc = get_next_thin(pool, tc);
3624 }
3625}
3626
3627static void pool_resume(struct dm_target *ti)
3628{
3629 struct pool_c *pt = ti->private;
3630 struct pool *pool = pt->pool;
3631
3632 /*
3633 * Must requeue active_thins' bios and then resume
3634 * active_thins _before_ clearing 'suspend' flag.
3635 */
3636 requeue_bios(pool);
3637 pool_resume_active_thins(pool);
3638
3639 spin_lock_irq(&pool->lock);
3640 pool->low_water_triggered = false;
3641 pool->suspended = false;
3642 spin_unlock_irq(&pool->lock);
3643
3644 do_waker(&pool->waker.work);
3645}
3646
3647static void pool_presuspend(struct dm_target *ti)
3648{
3649 struct pool_c *pt = ti->private;
3650 struct pool *pool = pt->pool;
3651
3652 spin_lock_irq(&pool->lock);
3653 pool->suspended = true;
3654 spin_unlock_irq(&pool->lock);
3655
3656 pool_suspend_active_thins(pool);
3657}
3658
3659static void pool_presuspend_undo(struct dm_target *ti)
3660{
3661 struct pool_c *pt = ti->private;
3662 struct pool *pool = pt->pool;
3663
3664 pool_resume_active_thins(pool);
3665
3666 spin_lock_irq(&pool->lock);
3667 pool->suspended = false;
3668 spin_unlock_irq(&pool->lock);
3669}
3670
3671static void pool_postsuspend(struct dm_target *ti)
3672{
3673 struct pool_c *pt = ti->private;
3674 struct pool *pool = pt->pool;
3675
3676 cancel_delayed_work_sync(&pool->waker);
3677 cancel_delayed_work_sync(&pool->no_space_timeout);
3678 flush_workqueue(pool->wq);
3679 (void) commit(pool);
3680}
3681
3682static int check_arg_count(unsigned int argc, unsigned int args_required)
3683{
3684 if (argc != args_required) {
3685 DMWARN("Message received with %u arguments instead of %u.",
3686 argc, args_required);
3687 return -EINVAL;
3688 }
3689
3690 return 0;
3691}
3692
3693static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3694{
3695 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3696 *dev_id <= MAX_DEV_ID)
3697 return 0;
3698
3699 if (warning)
3700 DMWARN("Message received with invalid device id: %s", arg);
3701
3702 return -EINVAL;
3703}
3704
3705static int process_create_thin_mesg(unsigned int argc, char **argv, struct pool *pool)
3706{
3707 dm_thin_id dev_id;
3708 int r;
3709
3710 r = check_arg_count(argc, 2);
3711 if (r)
3712 return r;
3713
3714 r = read_dev_id(argv[1], &dev_id, 1);
3715 if (r)
3716 return r;
3717
3718 r = dm_pool_create_thin(pool->pmd, dev_id);
3719 if (r) {
3720 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3721 argv[1]);
3722 return r;
3723 }
3724
3725 return 0;
3726}
3727
3728static int process_create_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3729{
3730 dm_thin_id dev_id;
3731 dm_thin_id origin_dev_id;
3732 int r;
3733
3734 r = check_arg_count(argc, 3);
3735 if (r)
3736 return r;
3737
3738 r = read_dev_id(argv[1], &dev_id, 1);
3739 if (r)
3740 return r;
3741
3742 r = read_dev_id(argv[2], &origin_dev_id, 1);
3743 if (r)
3744 return r;
3745
3746 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3747 if (r) {
3748 DMWARN("Creation of new snapshot %s of device %s failed.",
3749 argv[1], argv[2]);
3750 return r;
3751 }
3752
3753 return 0;
3754}
3755
3756static int process_delete_mesg(unsigned int argc, char **argv, struct pool *pool)
3757{
3758 dm_thin_id dev_id;
3759 int r;
3760
3761 r = check_arg_count(argc, 2);
3762 if (r)
3763 return r;
3764
3765 r = read_dev_id(argv[1], &dev_id, 1);
3766 if (r)
3767 return r;
3768
3769 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3770 if (r)
3771 DMWARN("Deletion of thin device %s failed.", argv[1]);
3772
3773 return r;
3774}
3775
3776static int process_set_transaction_id_mesg(unsigned int argc, char **argv, struct pool *pool)
3777{
3778 dm_thin_id old_id, new_id;
3779 int r;
3780
3781 r = check_arg_count(argc, 3);
3782 if (r)
3783 return r;
3784
3785 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3786 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3787 return -EINVAL;
3788 }
3789
3790 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3791 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3792 return -EINVAL;
3793 }
3794
3795 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3796 if (r) {
3797 DMWARN("Failed to change transaction id from %s to %s.",
3798 argv[1], argv[2]);
3799 return r;
3800 }
3801
3802 return 0;
3803}
3804
3805static int process_reserve_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3806{
3807 int r;
3808
3809 r = check_arg_count(argc, 1);
3810 if (r)
3811 return r;
3812
3813 (void) commit(pool);
3814
3815 r = dm_pool_reserve_metadata_snap(pool->pmd);
3816 if (r)
3817 DMWARN("reserve_metadata_snap message failed.");
3818
3819 return r;
3820}
3821
3822static int process_release_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3823{
3824 int r;
3825
3826 r = check_arg_count(argc, 1);
3827 if (r)
3828 return r;
3829
3830 r = dm_pool_release_metadata_snap(pool->pmd);
3831 if (r)
3832 DMWARN("release_metadata_snap message failed.");
3833
3834 return r;
3835}
3836
3837/*
3838 * Messages supported:
3839 * create_thin <dev_id>
3840 * create_snap <dev_id> <origin_id>
3841 * delete <dev_id>
3842 * set_transaction_id <current_trans_id> <new_trans_id>
3843 * reserve_metadata_snap
3844 * release_metadata_snap
3845 */
3846static int pool_message(struct dm_target *ti, unsigned int argc, char **argv,
3847 char *result, unsigned int maxlen)
3848{
3849 int r = -EINVAL;
3850 struct pool_c *pt = ti->private;
3851 struct pool *pool = pt->pool;
3852
3853 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) {
3854 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3855 dm_device_name(pool->pool_md));
3856 return -EOPNOTSUPP;
3857 }
3858
3859 if (!strcasecmp(argv[0], "create_thin"))
3860 r = process_create_thin_mesg(argc, argv, pool);
3861
3862 else if (!strcasecmp(argv[0], "create_snap"))
3863 r = process_create_snap_mesg(argc, argv, pool);
3864
3865 else if (!strcasecmp(argv[0], "delete"))
3866 r = process_delete_mesg(argc, argv, pool);
3867
3868 else if (!strcasecmp(argv[0], "set_transaction_id"))
3869 r = process_set_transaction_id_mesg(argc, argv, pool);
3870
3871 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3872 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3873
3874 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3875 r = process_release_metadata_snap_mesg(argc, argv, pool);
3876
3877 else
3878 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3879
3880 if (!r)
3881 (void) commit(pool);
3882
3883 return r;
3884}
3885
3886static void emit_flags(struct pool_features *pf, char *result,
3887 unsigned int sz, unsigned int maxlen)
3888{
3889 unsigned int count = !pf->zero_new_blocks + !pf->discard_enabled +
3890 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3891 pf->error_if_no_space;
3892 DMEMIT("%u ", count);
3893
3894 if (!pf->zero_new_blocks)
3895 DMEMIT("skip_block_zeroing ");
3896
3897 if (!pf->discard_enabled)
3898 DMEMIT("ignore_discard ");
3899
3900 if (!pf->discard_passdown)
3901 DMEMIT("no_discard_passdown ");
3902
3903 if (pf->mode == PM_READ_ONLY)
3904 DMEMIT("read_only ");
3905
3906 if (pf->error_if_no_space)
3907 DMEMIT("error_if_no_space ");
3908}
3909
3910/*
3911 * Status line is:
3912 * <transaction id> <used metadata sectors>/<total metadata sectors>
3913 * <used data sectors>/<total data sectors> <held metadata root>
3914 * <pool mode> <discard config> <no space config> <needs_check>
3915 */
3916static void pool_status(struct dm_target *ti, status_type_t type,
3917 unsigned int status_flags, char *result, unsigned int maxlen)
3918{
3919 int r;
3920 unsigned int sz = 0;
3921 uint64_t transaction_id;
3922 dm_block_t nr_free_blocks_data;
3923 dm_block_t nr_free_blocks_metadata;
3924 dm_block_t nr_blocks_data;
3925 dm_block_t nr_blocks_metadata;
3926 dm_block_t held_root;
3927 enum pool_mode mode;
3928 char buf[BDEVNAME_SIZE];
3929 char buf2[BDEVNAME_SIZE];
3930 struct pool_c *pt = ti->private;
3931 struct pool *pool = pt->pool;
3932
3933 switch (type) {
3934 case STATUSTYPE_INFO:
3935 if (get_pool_mode(pool) == PM_FAIL) {
3936 DMEMIT("Fail");
3937 break;
3938 }
3939
3940 /* Commit to ensure statistics aren't out-of-date */
3941 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3942 (void) commit(pool);
3943
3944 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3945 if (r) {
3946 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3947 dm_device_name(pool->pool_md), r);
3948 goto err;
3949 }
3950
3951 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3952 if (r) {
3953 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3954 dm_device_name(pool->pool_md), r);
3955 goto err;
3956 }
3957
3958 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3959 if (r) {
3960 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3961 dm_device_name(pool->pool_md), r);
3962 goto err;
3963 }
3964
3965 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3966 if (r) {
3967 DMERR("%s: dm_pool_get_free_block_count returned %d",
3968 dm_device_name(pool->pool_md), r);
3969 goto err;
3970 }
3971
3972 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3973 if (r) {
3974 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3975 dm_device_name(pool->pool_md), r);
3976 goto err;
3977 }
3978
3979 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3980 if (r) {
3981 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3982 dm_device_name(pool->pool_md), r);
3983 goto err;
3984 }
3985
3986 DMEMIT("%llu %llu/%llu %llu/%llu ",
3987 (unsigned long long)transaction_id,
3988 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3989 (unsigned long long)nr_blocks_metadata,
3990 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3991 (unsigned long long)nr_blocks_data);
3992
3993 if (held_root)
3994 DMEMIT("%llu ", held_root);
3995 else
3996 DMEMIT("- ");
3997
3998 mode = get_pool_mode(pool);
3999 if (mode == PM_OUT_OF_DATA_SPACE)
4000 DMEMIT("out_of_data_space ");
4001 else if (is_read_only_pool_mode(mode))
4002 DMEMIT("ro ");
4003 else
4004 DMEMIT("rw ");
4005
4006 if (!pool->pf.discard_enabled)
4007 DMEMIT("ignore_discard ");
4008 else if (pool->pf.discard_passdown)
4009 DMEMIT("discard_passdown ");
4010 else
4011 DMEMIT("no_discard_passdown ");
4012
4013 if (pool->pf.error_if_no_space)
4014 DMEMIT("error_if_no_space ");
4015 else
4016 DMEMIT("queue_if_no_space ");
4017
4018 if (dm_pool_metadata_needs_check(pool->pmd))
4019 DMEMIT("needs_check ");
4020 else
4021 DMEMIT("- ");
4022
4023 DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt));
4024
4025 break;
4026
4027 case STATUSTYPE_TABLE:
4028 DMEMIT("%s %s %lu %llu ",
4029 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
4030 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
4031 (unsigned long)pool->sectors_per_block,
4032 (unsigned long long)pt->low_water_blocks);
4033 emit_flags(&pt->requested_pf, result, sz, maxlen);
4034 break;
4035
4036 case STATUSTYPE_IMA:
4037 *result = '\0';
4038 break;
4039 }
4040 return;
4041
4042err:
4043 DMEMIT("Error");
4044}
4045
4046static int pool_iterate_devices(struct dm_target *ti,
4047 iterate_devices_callout_fn fn, void *data)
4048{
4049 struct pool_c *pt = ti->private;
4050
4051 return fn(ti, pt->data_dev, 0, ti->len, data);
4052}
4053
4054static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
4055{
4056 struct pool_c *pt = ti->private;
4057 struct pool *pool = pt->pool;
4058 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
4059
4060 /*
4061 * If max_sectors is smaller than pool->sectors_per_block adjust it
4062 * to the highest possible power-of-2 factor of pool->sectors_per_block.
4063 * This is especially beneficial when the pool's data device is a RAID
4064 * device that has a full stripe width that matches pool->sectors_per_block
4065 * -- because even though partial RAID stripe-sized IOs will be issued to a
4066 * single RAID stripe; when aggregated they will end on a full RAID stripe
4067 * boundary.. which avoids additional partial RAID stripe writes cascading
4068 */
4069 if (limits->max_sectors < pool->sectors_per_block) {
4070 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
4071 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
4072 limits->max_sectors--;
4073 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
4074 }
4075 }
4076
4077 /*
4078 * If the system-determined stacked limits are compatible with the
4079 * pool's blocksize (io_opt is a factor) do not override them.
4080 */
4081 if (io_opt_sectors < pool->sectors_per_block ||
4082 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
4083 if (is_factor(pool->sectors_per_block, limits->max_sectors))
4084 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
4085 else
4086 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
4087 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
4088 }
4089
4090 /*
4091 * pt->adjusted_pf is a staging area for the actual features to use.
4092 * They get transferred to the live pool in bind_control_target()
4093 * called from pool_preresume().
4094 */
4095
4096 if (pt->adjusted_pf.discard_enabled) {
4097 disable_discard_passdown_if_not_supported(pt);
4098 if (!pt->adjusted_pf.discard_passdown)
4099 limits->max_discard_sectors = 0;
4100 /*
4101 * The pool uses the same discard limits as the underlying data
4102 * device. DM core has already set this up.
4103 */
4104 } else {
4105 /*
4106 * Must explicitly disallow stacking discard limits otherwise the
4107 * block layer will stack them if pool's data device has support.
4108 */
4109 limits->discard_granularity = 0;
4110 }
4111}
4112
4113static struct target_type pool_target = {
4114 .name = "thin-pool",
4115 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
4116 DM_TARGET_IMMUTABLE,
4117 .version = {1, 23, 0},
4118 .module = THIS_MODULE,
4119 .ctr = pool_ctr,
4120 .dtr = pool_dtr,
4121 .map = pool_map,
4122 .presuspend = pool_presuspend,
4123 .presuspend_undo = pool_presuspend_undo,
4124 .postsuspend = pool_postsuspend,
4125 .preresume = pool_preresume,
4126 .resume = pool_resume,
4127 .message = pool_message,
4128 .status = pool_status,
4129 .iterate_devices = pool_iterate_devices,
4130 .io_hints = pool_io_hints,
4131};
4132
4133/*
4134 *--------------------------------------------------------------
4135 * Thin target methods
4136 *--------------------------------------------------------------
4137 */
4138static void thin_get(struct thin_c *tc)
4139{
4140 refcount_inc(&tc->refcount);
4141}
4142
4143static void thin_put(struct thin_c *tc)
4144{
4145 if (refcount_dec_and_test(&tc->refcount))
4146 complete(&tc->can_destroy);
4147}
4148
4149static void thin_dtr(struct dm_target *ti)
4150{
4151 struct thin_c *tc = ti->private;
4152
4153 spin_lock_irq(&tc->pool->lock);
4154 list_del_rcu(&tc->list);
4155 spin_unlock_irq(&tc->pool->lock);
4156 synchronize_rcu();
4157
4158 thin_put(tc);
4159 wait_for_completion(&tc->can_destroy);
4160
4161 mutex_lock(&dm_thin_pool_table.mutex);
4162
4163 __pool_dec(tc->pool);
4164 dm_pool_close_thin_device(tc->td);
4165 dm_put_device(ti, tc->pool_dev);
4166 if (tc->origin_dev)
4167 dm_put_device(ti, tc->origin_dev);
4168 kfree(tc);
4169
4170 mutex_unlock(&dm_thin_pool_table.mutex);
4171}
4172
4173/*
4174 * Thin target parameters:
4175 *
4176 * <pool_dev> <dev_id> [origin_dev]
4177 *
4178 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4179 * dev_id: the internal device identifier
4180 * origin_dev: a device external to the pool that should act as the origin
4181 *
4182 * If the pool device has discards disabled, they get disabled for the thin
4183 * device as well.
4184 */
4185static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
4186{
4187 int r;
4188 struct thin_c *tc;
4189 struct dm_dev *pool_dev, *origin_dev;
4190 struct mapped_device *pool_md;
4191
4192 mutex_lock(&dm_thin_pool_table.mutex);
4193
4194 if (argc != 2 && argc != 3) {
4195 ti->error = "Invalid argument count";
4196 r = -EINVAL;
4197 goto out_unlock;
4198 }
4199
4200 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4201 if (!tc) {
4202 ti->error = "Out of memory";
4203 r = -ENOMEM;
4204 goto out_unlock;
4205 }
4206 tc->thin_md = dm_table_get_md(ti->table);
4207 spin_lock_init(&tc->lock);
4208 INIT_LIST_HEAD(&tc->deferred_cells);
4209 bio_list_init(&tc->deferred_bio_list);
4210 bio_list_init(&tc->retry_on_resume_list);
4211 tc->sort_bio_list = RB_ROOT;
4212
4213 if (argc == 3) {
4214 if (!strcmp(argv[0], argv[2])) {
4215 ti->error = "Error setting origin device";
4216 r = -EINVAL;
4217 goto bad_origin_dev;
4218 }
4219
4220 r = dm_get_device(ti, argv[2], BLK_OPEN_READ, &origin_dev);
4221 if (r) {
4222 ti->error = "Error opening origin device";
4223 goto bad_origin_dev;
4224 }
4225 tc->origin_dev = origin_dev;
4226 }
4227
4228 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4229 if (r) {
4230 ti->error = "Error opening pool device";
4231 goto bad_pool_dev;
4232 }
4233 tc->pool_dev = pool_dev;
4234
4235 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4236 ti->error = "Invalid device id";
4237 r = -EINVAL;
4238 goto bad_common;
4239 }
4240
4241 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4242 if (!pool_md) {
4243 ti->error = "Couldn't get pool mapped device";
4244 r = -EINVAL;
4245 goto bad_common;
4246 }
4247
4248 tc->pool = __pool_table_lookup(pool_md);
4249 if (!tc->pool) {
4250 ti->error = "Couldn't find pool object";
4251 r = -EINVAL;
4252 goto bad_pool_lookup;
4253 }
4254 __pool_inc(tc->pool);
4255
4256 if (get_pool_mode(tc->pool) == PM_FAIL) {
4257 ti->error = "Couldn't open thin device, Pool is in fail mode";
4258 r = -EINVAL;
4259 goto bad_pool;
4260 }
4261
4262 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4263 if (r) {
4264 ti->error = "Couldn't open thin internal device";
4265 goto bad_pool;
4266 }
4267
4268 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4269 if (r)
4270 goto bad;
4271
4272 ti->num_flush_bios = 1;
4273 ti->limit_swap_bios = true;
4274 ti->flush_supported = true;
4275 ti->accounts_remapped_io = true;
4276 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4277
4278 /* In case the pool supports discards, pass them on. */
4279 if (tc->pool->pf.discard_enabled) {
4280 ti->discards_supported = true;
4281 ti->num_discard_bios = 1;
4282 ti->max_discard_granularity = true;
4283 }
4284
4285 mutex_unlock(&dm_thin_pool_table.mutex);
4286
4287 spin_lock_irq(&tc->pool->lock);
4288 if (tc->pool->suspended) {
4289 spin_unlock_irq(&tc->pool->lock);
4290 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
4291 ti->error = "Unable to activate thin device while pool is suspended";
4292 r = -EINVAL;
4293 goto bad;
4294 }
4295 refcount_set(&tc->refcount, 1);
4296 init_completion(&tc->can_destroy);
4297 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
4298 spin_unlock_irq(&tc->pool->lock);
4299 /*
4300 * This synchronize_rcu() call is needed here otherwise we risk a
4301 * wake_worker() call finding no bios to process (because the newly
4302 * added tc isn't yet visible). So this reduces latency since we
4303 * aren't then dependent on the periodic commit to wake_worker().
4304 */
4305 synchronize_rcu();
4306
4307 dm_put(pool_md);
4308
4309 return 0;
4310
4311bad:
4312 dm_pool_close_thin_device(tc->td);
4313bad_pool:
4314 __pool_dec(tc->pool);
4315bad_pool_lookup:
4316 dm_put(pool_md);
4317bad_common:
4318 dm_put_device(ti, tc->pool_dev);
4319bad_pool_dev:
4320 if (tc->origin_dev)
4321 dm_put_device(ti, tc->origin_dev);
4322bad_origin_dev:
4323 kfree(tc);
4324out_unlock:
4325 mutex_unlock(&dm_thin_pool_table.mutex);
4326
4327 return r;
4328}
4329
4330static int thin_map(struct dm_target *ti, struct bio *bio)
4331{
4332 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
4333
4334 return thin_bio_map(ti, bio);
4335}
4336
4337static int thin_endio(struct dm_target *ti, struct bio *bio,
4338 blk_status_t *err)
4339{
4340 unsigned long flags;
4341 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4342 struct list_head work;
4343 struct dm_thin_new_mapping *m, *tmp;
4344 struct pool *pool = h->tc->pool;
4345
4346 if (h->shared_read_entry) {
4347 INIT_LIST_HEAD(&work);
4348 dm_deferred_entry_dec(h->shared_read_entry, &work);
4349
4350 spin_lock_irqsave(&pool->lock, flags);
4351 list_for_each_entry_safe(m, tmp, &work, list) {
4352 list_del(&m->list);
4353 __complete_mapping_preparation(m);
4354 }
4355 spin_unlock_irqrestore(&pool->lock, flags);
4356 }
4357
4358 if (h->all_io_entry) {
4359 INIT_LIST_HEAD(&work);
4360 dm_deferred_entry_dec(h->all_io_entry, &work);
4361 if (!list_empty(&work)) {
4362 spin_lock_irqsave(&pool->lock, flags);
4363 list_for_each_entry_safe(m, tmp, &work, list)
4364 list_add_tail(&m->list, &pool->prepared_discards);
4365 spin_unlock_irqrestore(&pool->lock, flags);
4366 wake_worker(pool);
4367 }
4368 }
4369
4370 if (h->cell)
4371 cell_defer_no_holder(h->tc, h->cell);
4372
4373 return DM_ENDIO_DONE;
4374}
4375
4376static void thin_presuspend(struct dm_target *ti)
4377{
4378 struct thin_c *tc = ti->private;
4379
4380 if (dm_noflush_suspending(ti))
4381 noflush_work(tc, do_noflush_start);
4382}
4383
4384static void thin_postsuspend(struct dm_target *ti)
4385{
4386 struct thin_c *tc = ti->private;
4387
4388 /*
4389 * The dm_noflush_suspending flag has been cleared by now, so
4390 * unfortunately we must always run this.
4391 */
4392 noflush_work(tc, do_noflush_stop);
4393}
4394
4395static int thin_preresume(struct dm_target *ti)
4396{
4397 struct thin_c *tc = ti->private;
4398
4399 if (tc->origin_dev)
4400 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4401
4402 return 0;
4403}
4404
4405/*
4406 * <nr mapped sectors> <highest mapped sector>
4407 */
4408static void thin_status(struct dm_target *ti, status_type_t type,
4409 unsigned int status_flags, char *result, unsigned int maxlen)
4410{
4411 int r;
4412 ssize_t sz = 0;
4413 dm_block_t mapped, highest;
4414 char buf[BDEVNAME_SIZE];
4415 struct thin_c *tc = ti->private;
4416
4417 if (get_pool_mode(tc->pool) == PM_FAIL) {
4418 DMEMIT("Fail");
4419 return;
4420 }
4421
4422 if (!tc->td)
4423 DMEMIT("-");
4424 else {
4425 switch (type) {
4426 case STATUSTYPE_INFO:
4427 r = dm_thin_get_mapped_count(tc->td, &mapped);
4428 if (r) {
4429 DMERR("dm_thin_get_mapped_count returned %d", r);
4430 goto err;
4431 }
4432
4433 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4434 if (r < 0) {
4435 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4436 goto err;
4437 }
4438
4439 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4440 if (r)
4441 DMEMIT("%llu", ((highest + 1) *
4442 tc->pool->sectors_per_block) - 1);
4443 else
4444 DMEMIT("-");
4445 break;
4446
4447 case STATUSTYPE_TABLE:
4448 DMEMIT("%s %lu",
4449 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4450 (unsigned long) tc->dev_id);
4451 if (tc->origin_dev)
4452 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4453 break;
4454
4455 case STATUSTYPE_IMA:
4456 *result = '\0';
4457 break;
4458 }
4459 }
4460
4461 return;
4462
4463err:
4464 DMEMIT("Error");
4465}
4466
4467static int thin_iterate_devices(struct dm_target *ti,
4468 iterate_devices_callout_fn fn, void *data)
4469{
4470 sector_t blocks;
4471 struct thin_c *tc = ti->private;
4472 struct pool *pool = tc->pool;
4473
4474 /*
4475 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4476 * we follow a more convoluted path through to the pool's target.
4477 */
4478 if (!pool->ti)
4479 return 0; /* nothing is bound */
4480
4481 blocks = pool->ti->len;
4482 (void) sector_div(blocks, pool->sectors_per_block);
4483 if (blocks)
4484 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4485
4486 return 0;
4487}
4488
4489static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4490{
4491 struct thin_c *tc = ti->private;
4492 struct pool *pool = tc->pool;
4493
4494 if (pool->pf.discard_enabled) {
4495 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4496 limits->max_discard_sectors = pool->sectors_per_block * BIO_PRISON_MAX_RANGE;
4497 }
4498}
4499
4500static struct target_type thin_target = {
4501 .name = "thin",
4502 .version = {1, 23, 0},
4503 .module = THIS_MODULE,
4504 .ctr = thin_ctr,
4505 .dtr = thin_dtr,
4506 .map = thin_map,
4507 .end_io = thin_endio,
4508 .preresume = thin_preresume,
4509 .presuspend = thin_presuspend,
4510 .postsuspend = thin_postsuspend,
4511 .status = thin_status,
4512 .iterate_devices = thin_iterate_devices,
4513 .io_hints = thin_io_hints,
4514};
4515
4516/*----------------------------------------------------------------*/
4517
4518static int __init dm_thin_init(void)
4519{
4520 int r = -ENOMEM;
4521
4522 pool_table_init();
4523
4524 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4525 if (!_new_mapping_cache)
4526 return r;
4527
4528 r = dm_register_target(&thin_target);
4529 if (r)
4530 goto bad_new_mapping_cache;
4531
4532 r = dm_register_target(&pool_target);
4533 if (r)
4534 goto bad_thin_target;
4535
4536 return 0;
4537
4538bad_thin_target:
4539 dm_unregister_target(&thin_target);
4540bad_new_mapping_cache:
4541 kmem_cache_destroy(_new_mapping_cache);
4542
4543 return r;
4544}
4545
4546static void dm_thin_exit(void)
4547{
4548 dm_unregister_target(&thin_target);
4549 dm_unregister_target(&pool_target);
4550
4551 kmem_cache_destroy(_new_mapping_cache);
4552
4553 pool_table_exit();
4554}
4555
4556module_init(dm_thin_init);
4557module_exit(dm_thin_exit);
4558
4559module_param_named(no_space_timeout, no_space_timeout_secs, uint, 0644);
4560MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4561
4562MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4563MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
4564MODULE_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.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_error)
387 op->parent_bio->bi_error = 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, int error_code)
454{
455 dm_cell_error(pool->prison, cell, error_code);
456 dm_bio_prison_free_cell(pool->prison, cell);
457}
458
459static int get_pool_io_error_code(struct pool *pool)
460{
461 return pool->out_of_data_space ? -ENOSPC : -EIO;
462}
463
464static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
465{
466 int error = get_pool_io_error_code(pool);
467
468 cell_error_with_code(pool, cell, error);
469}
470
471static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
472{
473 cell_error_with_code(pool, cell, 0);
474}
475
476static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
477{
478 cell_error_with_code(pool, cell, DM_ENDIO_REQUEUE);
479}
480
481/*----------------------------------------------------------------*/
482
483/*
484 * A global list of pools that uses a struct mapped_device as a key.
485 */
486static struct dm_thin_pool_table {
487 struct mutex mutex;
488 struct list_head pools;
489} dm_thin_pool_table;
490
491static void pool_table_init(void)
492{
493 mutex_init(&dm_thin_pool_table.mutex);
494 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
495}
496
497static void __pool_table_insert(struct pool *pool)
498{
499 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
500 list_add(&pool->list, &dm_thin_pool_table.pools);
501}
502
503static void __pool_table_remove(struct pool *pool)
504{
505 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
506 list_del(&pool->list);
507}
508
509static struct pool *__pool_table_lookup(struct mapped_device *md)
510{
511 struct pool *pool = NULL, *tmp;
512
513 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
514
515 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
516 if (tmp->pool_md == md) {
517 pool = tmp;
518 break;
519 }
520 }
521
522 return pool;
523}
524
525static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
526{
527 struct pool *pool = NULL, *tmp;
528
529 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
530
531 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
532 if (tmp->md_dev == md_dev) {
533 pool = tmp;
534 break;
535 }
536 }
537
538 return pool;
539}
540
541/*----------------------------------------------------------------*/
542
543struct dm_thin_endio_hook {
544 struct thin_c *tc;
545 struct dm_deferred_entry *shared_read_entry;
546 struct dm_deferred_entry *all_io_entry;
547 struct dm_thin_new_mapping *overwrite_mapping;
548 struct rb_node rb_node;
549 struct dm_bio_prison_cell *cell;
550};
551
552static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
553{
554 bio_list_merge(bios, master);
555 bio_list_init(master);
556}
557
558static void error_bio_list(struct bio_list *bios, int error)
559{
560 struct bio *bio;
561
562 while ((bio = bio_list_pop(bios))) {
563 bio->bi_error = error;
564 bio_endio(bio);
565 }
566}
567
568static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, int error)
569{
570 struct bio_list bios;
571 unsigned long flags;
572
573 bio_list_init(&bios);
574
575 spin_lock_irqsave(&tc->lock, flags);
576 __merge_bio_list(&bios, master);
577 spin_unlock_irqrestore(&tc->lock, flags);
578
579 error_bio_list(&bios, error);
580}
581
582static void requeue_deferred_cells(struct thin_c *tc)
583{
584 struct pool *pool = tc->pool;
585 unsigned long flags;
586 struct list_head cells;
587 struct dm_bio_prison_cell *cell, *tmp;
588
589 INIT_LIST_HEAD(&cells);
590
591 spin_lock_irqsave(&tc->lock, flags);
592 list_splice_init(&tc->deferred_cells, &cells);
593 spin_unlock_irqrestore(&tc->lock, flags);
594
595 list_for_each_entry_safe(cell, tmp, &cells, user_list)
596 cell_requeue(pool, cell);
597}
598
599static void requeue_io(struct thin_c *tc)
600{
601 struct bio_list bios;
602 unsigned long flags;
603
604 bio_list_init(&bios);
605
606 spin_lock_irqsave(&tc->lock, flags);
607 __merge_bio_list(&bios, &tc->deferred_bio_list);
608 __merge_bio_list(&bios, &tc->retry_on_resume_list);
609 spin_unlock_irqrestore(&tc->lock, flags);
610
611 error_bio_list(&bios, DM_ENDIO_REQUEUE);
612 requeue_deferred_cells(tc);
613}
614
615static void error_retry_list_with_code(struct pool *pool, int error)
616{
617 struct thin_c *tc;
618
619 rcu_read_lock();
620 list_for_each_entry_rcu(tc, &pool->active_thins, list)
621 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
622 rcu_read_unlock();
623}
624
625static void error_retry_list(struct pool *pool)
626{
627 int error = get_pool_io_error_code(pool);
628
629 error_retry_list_with_code(pool, error);
630}
631
632/*
633 * This section of code contains the logic for processing a thin device's IO.
634 * Much of the code depends on pool object resources (lists, workqueues, etc)
635 * but most is exclusively called from the thin target rather than the thin-pool
636 * target.
637 */
638
639static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
640{
641 struct pool *pool = tc->pool;
642 sector_t block_nr = bio->bi_iter.bi_sector;
643
644 if (block_size_is_power_of_two(pool))
645 block_nr >>= pool->sectors_per_block_shift;
646 else
647 (void) sector_div(block_nr, pool->sectors_per_block);
648
649 return block_nr;
650}
651
652/*
653 * Returns the _complete_ blocks that this bio covers.
654 */
655static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
656 dm_block_t *begin, dm_block_t *end)
657{
658 struct pool *pool = tc->pool;
659 sector_t b = bio->bi_iter.bi_sector;
660 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
661
662 b += pool->sectors_per_block - 1ull; /* so we round up */
663
664 if (block_size_is_power_of_two(pool)) {
665 b >>= pool->sectors_per_block_shift;
666 e >>= pool->sectors_per_block_shift;
667 } else {
668 (void) sector_div(b, pool->sectors_per_block);
669 (void) sector_div(e, pool->sectors_per_block);
670 }
671
672 if (e < b)
673 /* Can happen if the bio is within a single block. */
674 e = b;
675
676 *begin = b;
677 *end = e;
678}
679
680static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
681{
682 struct pool *pool = tc->pool;
683 sector_t bi_sector = bio->bi_iter.bi_sector;
684
685 bio->bi_bdev = tc->pool_dev->bdev;
686 if (block_size_is_power_of_two(pool))
687 bio->bi_iter.bi_sector =
688 (block << pool->sectors_per_block_shift) |
689 (bi_sector & (pool->sectors_per_block - 1));
690 else
691 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
692 sector_div(bi_sector, pool->sectors_per_block);
693}
694
695static void remap_to_origin(struct thin_c *tc, struct bio *bio)
696{
697 bio->bi_bdev = tc->origin_dev->bdev;
698}
699
700static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
701{
702 return (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA)) &&
703 dm_thin_changed_this_transaction(tc->td);
704}
705
706static void inc_all_io_entry(struct pool *pool, struct bio *bio)
707{
708 struct dm_thin_endio_hook *h;
709
710 if (bio_op(bio) == REQ_OP_DISCARD)
711 return;
712
713 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
714 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
715}
716
717static void issue(struct thin_c *tc, struct bio *bio)
718{
719 struct pool *pool = tc->pool;
720 unsigned long flags;
721
722 if (!bio_triggers_commit(tc, bio)) {
723 generic_make_request(bio);
724 return;
725 }
726
727 /*
728 * Complete bio with an error if earlier I/O caused changes to
729 * the metadata that can't be committed e.g, due to I/O errors
730 * on the metadata device.
731 */
732 if (dm_thin_aborted_changes(tc->td)) {
733 bio_io_error(bio);
734 return;
735 }
736
737 /*
738 * Batch together any bios that trigger commits and then issue a
739 * single commit for them in process_deferred_bios().
740 */
741 spin_lock_irqsave(&pool->lock, flags);
742 bio_list_add(&pool->deferred_flush_bios, bio);
743 spin_unlock_irqrestore(&pool->lock, flags);
744}
745
746static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
747{
748 remap_to_origin(tc, bio);
749 issue(tc, bio);
750}
751
752static void remap_and_issue(struct thin_c *tc, struct bio *bio,
753 dm_block_t block)
754{
755 remap(tc, bio, block);
756 issue(tc, bio);
757}
758
759/*----------------------------------------------------------------*/
760
761/*
762 * Bio endio functions.
763 */
764struct dm_thin_new_mapping {
765 struct list_head list;
766
767 bool pass_discard:1;
768 bool maybe_shared:1;
769
770 /*
771 * Track quiescing, copying and zeroing preparation actions. When this
772 * counter hits zero the block is prepared and can be inserted into the
773 * btree.
774 */
775 atomic_t prepare_actions;
776
777 int err;
778 struct thin_c *tc;
779 dm_block_t virt_begin, virt_end;
780 dm_block_t data_block;
781 struct dm_bio_prison_cell *cell;
782
783 /*
784 * If the bio covers the whole area of a block then we can avoid
785 * zeroing or copying. Instead this bio is hooked. The bio will
786 * still be in the cell, so care has to be taken to avoid issuing
787 * the bio twice.
788 */
789 struct bio *bio;
790 bio_end_io_t *saved_bi_end_io;
791};
792
793static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
794{
795 struct pool *pool = m->tc->pool;
796
797 if (atomic_dec_and_test(&m->prepare_actions)) {
798 list_add_tail(&m->list, &pool->prepared_mappings);
799 wake_worker(pool);
800 }
801}
802
803static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
804{
805 unsigned long flags;
806 struct pool *pool = m->tc->pool;
807
808 spin_lock_irqsave(&pool->lock, flags);
809 __complete_mapping_preparation(m);
810 spin_unlock_irqrestore(&pool->lock, flags);
811}
812
813static void copy_complete(int read_err, unsigned long write_err, void *context)
814{
815 struct dm_thin_new_mapping *m = context;
816
817 m->err = read_err || write_err ? -EIO : 0;
818 complete_mapping_preparation(m);
819}
820
821static void overwrite_endio(struct bio *bio)
822{
823 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
824 struct dm_thin_new_mapping *m = h->overwrite_mapping;
825
826 bio->bi_end_io = m->saved_bi_end_io;
827
828 m->err = bio->bi_error;
829 complete_mapping_preparation(m);
830}
831
832/*----------------------------------------------------------------*/
833
834/*
835 * Workqueue.
836 */
837
838/*
839 * Prepared mapping jobs.
840 */
841
842/*
843 * This sends the bios in the cell, except the original holder, back
844 * to the deferred_bios list.
845 */
846static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
847{
848 struct pool *pool = tc->pool;
849 unsigned long flags;
850
851 spin_lock_irqsave(&tc->lock, flags);
852 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
853 spin_unlock_irqrestore(&tc->lock, flags);
854
855 wake_worker(pool);
856}
857
858static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
859
860struct remap_info {
861 struct thin_c *tc;
862 struct bio_list defer_bios;
863 struct bio_list issue_bios;
864};
865
866static void __inc_remap_and_issue_cell(void *context,
867 struct dm_bio_prison_cell *cell)
868{
869 struct remap_info *info = context;
870 struct bio *bio;
871
872 while ((bio = bio_list_pop(&cell->bios))) {
873 if (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA) ||
874 bio_op(bio) == REQ_OP_DISCARD)
875 bio_list_add(&info->defer_bios, bio);
876 else {
877 inc_all_io_entry(info->tc->pool, bio);
878
879 /*
880 * We can't issue the bios with the bio prison lock
881 * held, so we add them to a list to issue on
882 * return from this function.
883 */
884 bio_list_add(&info->issue_bios, bio);
885 }
886 }
887}
888
889static void inc_remap_and_issue_cell(struct thin_c *tc,
890 struct dm_bio_prison_cell *cell,
891 dm_block_t block)
892{
893 struct bio *bio;
894 struct remap_info info;
895
896 info.tc = tc;
897 bio_list_init(&info.defer_bios);
898 bio_list_init(&info.issue_bios);
899
900 /*
901 * We have to be careful to inc any bios we're about to issue
902 * before the cell is released, and avoid a race with new bios
903 * being added to the cell.
904 */
905 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
906 &info, cell);
907
908 while ((bio = bio_list_pop(&info.defer_bios)))
909 thin_defer_bio(tc, bio);
910
911 while ((bio = bio_list_pop(&info.issue_bios)))
912 remap_and_issue(info.tc, bio, block);
913}
914
915static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
916{
917 cell_error(m->tc->pool, m->cell);
918 list_del(&m->list);
919 mempool_free(m, m->tc->pool->mapping_pool);
920}
921
922static void process_prepared_mapping(struct dm_thin_new_mapping *m)
923{
924 struct thin_c *tc = m->tc;
925 struct pool *pool = tc->pool;
926 struct bio *bio = m->bio;
927 int r;
928
929 if (m->err) {
930 cell_error(pool, m->cell);
931 goto out;
932 }
933
934 /*
935 * Commit the prepared block into the mapping btree.
936 * Any I/O for this block arriving after this point will get
937 * remapped to it directly.
938 */
939 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
940 if (r) {
941 metadata_operation_failed(pool, "dm_thin_insert_block", r);
942 cell_error(pool, m->cell);
943 goto out;
944 }
945
946 /*
947 * Release any bios held while the block was being provisioned.
948 * If we are processing a write bio that completely covers the block,
949 * we already processed it so can ignore it now when processing
950 * the bios in the cell.
951 */
952 if (bio) {
953 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
954 bio_endio(bio);
955 } else {
956 inc_all_io_entry(tc->pool, m->cell->holder);
957 remap_and_issue(tc, m->cell->holder, m->data_block);
958 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
959 }
960
961out:
962 list_del(&m->list);
963 mempool_free(m, pool->mapping_pool);
964}
965
966/*----------------------------------------------------------------*/
967
968static void free_discard_mapping(struct dm_thin_new_mapping *m)
969{
970 struct thin_c *tc = m->tc;
971 if (m->cell)
972 cell_defer_no_holder(tc, m->cell);
973 mempool_free(m, tc->pool->mapping_pool);
974}
975
976static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
977{
978 bio_io_error(m->bio);
979 free_discard_mapping(m);
980}
981
982static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
983{
984 bio_endio(m->bio);
985 free_discard_mapping(m);
986}
987
988static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
989{
990 int r;
991 struct thin_c *tc = m->tc;
992
993 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
994 if (r) {
995 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
996 bio_io_error(m->bio);
997 } else
998 bio_endio(m->bio);
999
1000 cell_defer_no_holder(tc, m->cell);
1001 mempool_free(m, tc->pool->mapping_pool);
1002}
1003
1004/*----------------------------------------------------------------*/
1005
1006static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
1007 struct bio *discard_parent)
1008{
1009 /*
1010 * We've already unmapped this range of blocks, but before we
1011 * passdown we have to check that these blocks are now unused.
1012 */
1013 int r = 0;
1014 bool used = true;
1015 struct thin_c *tc = m->tc;
1016 struct pool *pool = tc->pool;
1017 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
1018 struct discard_op op;
1019
1020 begin_discard(&op, tc, discard_parent);
1021 while (b != end) {
1022 /* find start of unmapped run */
1023 for (; b < end; b++) {
1024 r = dm_pool_block_is_used(pool->pmd, b, &used);
1025 if (r)
1026 goto out;
1027
1028 if (!used)
1029 break;
1030 }
1031
1032 if (b == end)
1033 break;
1034
1035 /* find end of run */
1036 for (e = b + 1; e != end; e++) {
1037 r = dm_pool_block_is_used(pool->pmd, e, &used);
1038 if (r)
1039 goto out;
1040
1041 if (used)
1042 break;
1043 }
1044
1045 r = issue_discard(&op, b, e);
1046 if (r)
1047 goto out;
1048
1049 b = e;
1050 }
1051out:
1052 end_discard(&op, r);
1053}
1054
1055static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
1056{
1057 unsigned long flags;
1058 struct pool *pool = m->tc->pool;
1059
1060 spin_lock_irqsave(&pool->lock, flags);
1061 list_add_tail(&m->list, &pool->prepared_discards_pt2);
1062 spin_unlock_irqrestore(&pool->lock, flags);
1063 wake_worker(pool);
1064}
1065
1066static void passdown_endio(struct bio *bio)
1067{
1068 /*
1069 * It doesn't matter if the passdown discard failed, we still want
1070 * to unmap (we ignore err).
1071 */
1072 queue_passdown_pt2(bio->bi_private);
1073}
1074
1075static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
1076{
1077 int r;
1078 struct thin_c *tc = m->tc;
1079 struct pool *pool = tc->pool;
1080 struct bio *discard_parent;
1081 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
1082
1083 /*
1084 * Only this thread allocates blocks, so we can be sure that the
1085 * newly unmapped blocks will not be allocated before the end of
1086 * the function.
1087 */
1088 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
1089 if (r) {
1090 metadata_operation_failed(pool, "dm_thin_remove_range", r);
1091 bio_io_error(m->bio);
1092 cell_defer_no_holder(tc, m->cell);
1093 mempool_free(m, pool->mapping_pool);
1094 return;
1095 }
1096
1097 discard_parent = bio_alloc(GFP_NOIO, 1);
1098 if (!discard_parent) {
1099 DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.",
1100 dm_device_name(tc->pool->pool_md));
1101 queue_passdown_pt2(m);
1102
1103 } else {
1104 discard_parent->bi_end_io = passdown_endio;
1105 discard_parent->bi_private = m;
1106
1107 if (m->maybe_shared)
1108 passdown_double_checking_shared_status(m, discard_parent);
1109 else {
1110 struct discard_op op;
1111
1112 begin_discard(&op, tc, discard_parent);
1113 r = issue_discard(&op, m->data_block, data_end);
1114 end_discard(&op, r);
1115 }
1116 }
1117
1118 /*
1119 * Increment the unmapped blocks. This prevents a race between the
1120 * passdown io and reallocation of freed blocks.
1121 */
1122 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
1123 if (r) {
1124 metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
1125 bio_io_error(m->bio);
1126 cell_defer_no_holder(tc, m->cell);
1127 mempool_free(m, pool->mapping_pool);
1128 return;
1129 }
1130}
1131
1132static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1133{
1134 int r;
1135 struct thin_c *tc = m->tc;
1136 struct pool *pool = tc->pool;
1137
1138 /*
1139 * The passdown has completed, so now we can decrement all those
1140 * unmapped blocks.
1141 */
1142 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1143 m->data_block + (m->virt_end - m->virt_begin));
1144 if (r) {
1145 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1146 bio_io_error(m->bio);
1147 } else
1148 bio_endio(m->bio);
1149
1150 cell_defer_no_holder(tc, m->cell);
1151 mempool_free(m, pool->mapping_pool);
1152}
1153
1154static void process_prepared(struct pool *pool, struct list_head *head,
1155 process_mapping_fn *fn)
1156{
1157 unsigned long flags;
1158 struct list_head maps;
1159 struct dm_thin_new_mapping *m, *tmp;
1160
1161 INIT_LIST_HEAD(&maps);
1162 spin_lock_irqsave(&pool->lock, flags);
1163 list_splice_init(head, &maps);
1164 spin_unlock_irqrestore(&pool->lock, flags);
1165
1166 list_for_each_entry_safe(m, tmp, &maps, list)
1167 (*fn)(m);
1168}
1169
1170/*
1171 * Deferred bio jobs.
1172 */
1173static int io_overlaps_block(struct pool *pool, struct bio *bio)
1174{
1175 return bio->bi_iter.bi_size ==
1176 (pool->sectors_per_block << SECTOR_SHIFT);
1177}
1178
1179static int io_overwrites_block(struct pool *pool, struct bio *bio)
1180{
1181 return (bio_data_dir(bio) == WRITE) &&
1182 io_overlaps_block(pool, bio);
1183}
1184
1185static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1186 bio_end_io_t *fn)
1187{
1188 *save = bio->bi_end_io;
1189 bio->bi_end_io = fn;
1190}
1191
1192static int ensure_next_mapping(struct pool *pool)
1193{
1194 if (pool->next_mapping)
1195 return 0;
1196
1197 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
1198
1199 return pool->next_mapping ? 0 : -ENOMEM;
1200}
1201
1202static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1203{
1204 struct dm_thin_new_mapping *m = pool->next_mapping;
1205
1206 BUG_ON(!pool->next_mapping);
1207
1208 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1209 INIT_LIST_HEAD(&m->list);
1210 m->bio = NULL;
1211
1212 pool->next_mapping = NULL;
1213
1214 return m;
1215}
1216
1217static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1218 sector_t begin, sector_t end)
1219{
1220 int r;
1221 struct dm_io_region to;
1222
1223 to.bdev = tc->pool_dev->bdev;
1224 to.sector = begin;
1225 to.count = end - begin;
1226
1227 r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1228 if (r < 0) {
1229 DMERR_LIMIT("dm_kcopyd_zero() failed");
1230 copy_complete(1, 1, m);
1231 }
1232}
1233
1234static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1235 dm_block_t data_begin,
1236 struct dm_thin_new_mapping *m)
1237{
1238 struct pool *pool = tc->pool;
1239 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1240
1241 h->overwrite_mapping = m;
1242 m->bio = bio;
1243 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1244 inc_all_io_entry(pool, bio);
1245 remap_and_issue(tc, bio, data_begin);
1246}
1247
1248/*
1249 * A partial copy also needs to zero the uncopied region.
1250 */
1251static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1252 struct dm_dev *origin, dm_block_t data_origin,
1253 dm_block_t data_dest,
1254 struct dm_bio_prison_cell *cell, struct bio *bio,
1255 sector_t len)
1256{
1257 int r;
1258 struct pool *pool = tc->pool;
1259 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1260
1261 m->tc = tc;
1262 m->virt_begin = virt_block;
1263 m->virt_end = virt_block + 1u;
1264 m->data_block = data_dest;
1265 m->cell = cell;
1266
1267 /*
1268 * quiesce action + copy action + an extra reference held for the
1269 * duration of this function (we may need to inc later for a
1270 * partial zero).
1271 */
1272 atomic_set(&m->prepare_actions, 3);
1273
1274 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1275 complete_mapping_preparation(m); /* already quiesced */
1276
1277 /*
1278 * IO to pool_dev remaps to the pool target's data_dev.
1279 *
1280 * If the whole block of data is being overwritten, we can issue the
1281 * bio immediately. Otherwise we use kcopyd to clone the data first.
1282 */
1283 if (io_overwrites_block(pool, bio))
1284 remap_and_issue_overwrite(tc, bio, data_dest, m);
1285 else {
1286 struct dm_io_region from, to;
1287
1288 from.bdev = origin->bdev;
1289 from.sector = data_origin * pool->sectors_per_block;
1290 from.count = len;
1291
1292 to.bdev = tc->pool_dev->bdev;
1293 to.sector = data_dest * pool->sectors_per_block;
1294 to.count = len;
1295
1296 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
1297 0, copy_complete, m);
1298 if (r < 0) {
1299 DMERR_LIMIT("dm_kcopyd_copy() failed");
1300 copy_complete(1, 1, m);
1301
1302 /*
1303 * We allow the zero to be issued, to simplify the
1304 * error path. Otherwise we'd need to start
1305 * worrying about decrementing the prepare_actions
1306 * counter.
1307 */
1308 }
1309
1310 /*
1311 * Do we need to zero a tail region?
1312 */
1313 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1314 atomic_inc(&m->prepare_actions);
1315 ll_zero(tc, m,
1316 data_dest * pool->sectors_per_block + len,
1317 (data_dest + 1) * pool->sectors_per_block);
1318 }
1319 }
1320
1321 complete_mapping_preparation(m); /* drop our ref */
1322}
1323
1324static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1325 dm_block_t data_origin, dm_block_t data_dest,
1326 struct dm_bio_prison_cell *cell, struct bio *bio)
1327{
1328 schedule_copy(tc, virt_block, tc->pool_dev,
1329 data_origin, data_dest, cell, bio,
1330 tc->pool->sectors_per_block);
1331}
1332
1333static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1334 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1335 struct bio *bio)
1336{
1337 struct pool *pool = tc->pool;
1338 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1339
1340 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1341 m->tc = tc;
1342 m->virt_begin = virt_block;
1343 m->virt_end = virt_block + 1u;
1344 m->data_block = data_block;
1345 m->cell = cell;
1346
1347 /*
1348 * If the whole block of data is being overwritten or we are not
1349 * zeroing pre-existing data, we can issue the bio immediately.
1350 * Otherwise we use kcopyd to zero the data first.
1351 */
1352 if (pool->pf.zero_new_blocks) {
1353 if (io_overwrites_block(pool, bio))
1354 remap_and_issue_overwrite(tc, bio, data_block, m);
1355 else
1356 ll_zero(tc, m, data_block * pool->sectors_per_block,
1357 (data_block + 1) * pool->sectors_per_block);
1358 } else
1359 process_prepared_mapping(m);
1360}
1361
1362static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1363 dm_block_t data_dest,
1364 struct dm_bio_prison_cell *cell, struct bio *bio)
1365{
1366 struct pool *pool = tc->pool;
1367 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1368 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1369
1370 if (virt_block_end <= tc->origin_size)
1371 schedule_copy(tc, virt_block, tc->origin_dev,
1372 virt_block, data_dest, cell, bio,
1373 pool->sectors_per_block);
1374
1375 else if (virt_block_begin < tc->origin_size)
1376 schedule_copy(tc, virt_block, tc->origin_dev,
1377 virt_block, data_dest, cell, bio,
1378 tc->origin_size - virt_block_begin);
1379
1380 else
1381 schedule_zero(tc, virt_block, data_dest, cell, bio);
1382}
1383
1384static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1385
1386static void check_for_space(struct pool *pool)
1387{
1388 int r;
1389 dm_block_t nr_free;
1390
1391 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1392 return;
1393
1394 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1395 if (r)
1396 return;
1397
1398 if (nr_free)
1399 set_pool_mode(pool, PM_WRITE);
1400}
1401
1402/*
1403 * A non-zero return indicates read_only or fail_io mode.
1404 * Many callers don't care about the return value.
1405 */
1406static int commit(struct pool *pool)
1407{
1408 int r;
1409
1410 if (get_pool_mode(pool) >= PM_READ_ONLY)
1411 return -EINVAL;
1412
1413 r = dm_pool_commit_metadata(pool->pmd);
1414 if (r)
1415 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1416 else
1417 check_for_space(pool);
1418
1419 return r;
1420}
1421
1422static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1423{
1424 unsigned long flags;
1425
1426 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1427 DMWARN("%s: reached low water mark for data device: sending event.",
1428 dm_device_name(pool->pool_md));
1429 spin_lock_irqsave(&pool->lock, flags);
1430 pool->low_water_triggered = true;
1431 spin_unlock_irqrestore(&pool->lock, flags);
1432 dm_table_event(pool->ti->table);
1433 }
1434}
1435
1436static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1437{
1438 int r;
1439 dm_block_t free_blocks;
1440 struct pool *pool = tc->pool;
1441
1442 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1443 return -EINVAL;
1444
1445 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1446 if (r) {
1447 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1448 return r;
1449 }
1450
1451 check_low_water_mark(pool, free_blocks);
1452
1453 if (!free_blocks) {
1454 /*
1455 * Try to commit to see if that will free up some
1456 * more space.
1457 */
1458 r = commit(pool);
1459 if (r)
1460 return r;
1461
1462 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1463 if (r) {
1464 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1465 return r;
1466 }
1467
1468 if (!free_blocks) {
1469 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1470 return -ENOSPC;
1471 }
1472 }
1473
1474 r = dm_pool_alloc_data_block(pool->pmd, result);
1475 if (r) {
1476 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1477 return r;
1478 }
1479
1480 return 0;
1481}
1482
1483/*
1484 * If we have run out of space, queue bios until the device is
1485 * resumed, presumably after having been reloaded with more space.
1486 */
1487static void retry_on_resume(struct bio *bio)
1488{
1489 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1490 struct thin_c *tc = h->tc;
1491 unsigned long flags;
1492
1493 spin_lock_irqsave(&tc->lock, flags);
1494 bio_list_add(&tc->retry_on_resume_list, bio);
1495 spin_unlock_irqrestore(&tc->lock, flags);
1496}
1497
1498static int should_error_unserviceable_bio(struct pool *pool)
1499{
1500 enum pool_mode m = get_pool_mode(pool);
1501
1502 switch (m) {
1503 case PM_WRITE:
1504 /* Shouldn't get here */
1505 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1506 return -EIO;
1507
1508 case PM_OUT_OF_DATA_SPACE:
1509 return pool->pf.error_if_no_space ? -ENOSPC : 0;
1510
1511 case PM_READ_ONLY:
1512 case PM_FAIL:
1513 return -EIO;
1514 default:
1515 /* Shouldn't get here */
1516 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1517 return -EIO;
1518 }
1519}
1520
1521static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1522{
1523 int error = should_error_unserviceable_bio(pool);
1524
1525 if (error) {
1526 bio->bi_error = error;
1527 bio_endio(bio);
1528 } else
1529 retry_on_resume(bio);
1530}
1531
1532static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1533{
1534 struct bio *bio;
1535 struct bio_list bios;
1536 int error;
1537
1538 error = should_error_unserviceable_bio(pool);
1539 if (error) {
1540 cell_error_with_code(pool, cell, error);
1541 return;
1542 }
1543
1544 bio_list_init(&bios);
1545 cell_release(pool, cell, &bios);
1546
1547 while ((bio = bio_list_pop(&bios)))
1548 retry_on_resume(bio);
1549}
1550
1551static void process_discard_cell_no_passdown(struct thin_c *tc,
1552 struct dm_bio_prison_cell *virt_cell)
1553{
1554 struct pool *pool = tc->pool;
1555 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1556
1557 /*
1558 * We don't need to lock the data blocks, since there's no
1559 * passdown. We only lock data blocks for allocation and breaking sharing.
1560 */
1561 m->tc = tc;
1562 m->virt_begin = virt_cell->key.block_begin;
1563 m->virt_end = virt_cell->key.block_end;
1564 m->cell = virt_cell;
1565 m->bio = virt_cell->holder;
1566
1567 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1568 pool->process_prepared_discard(m);
1569}
1570
1571static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1572 struct bio *bio)
1573{
1574 struct pool *pool = tc->pool;
1575
1576 int r;
1577 bool maybe_shared;
1578 struct dm_cell_key data_key;
1579 struct dm_bio_prison_cell *data_cell;
1580 struct dm_thin_new_mapping *m;
1581 dm_block_t virt_begin, virt_end, data_begin;
1582
1583 while (begin != end) {
1584 r = ensure_next_mapping(pool);
1585 if (r)
1586 /* we did our best */
1587 return;
1588
1589 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1590 &data_begin, &maybe_shared);
1591 if (r)
1592 /*
1593 * Silently fail, letting any mappings we've
1594 * created complete.
1595 */
1596 break;
1597
1598 build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key);
1599 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1600 /* contention, we'll give up with this range */
1601 begin = virt_end;
1602 continue;
1603 }
1604
1605 /*
1606 * IO may still be going to the destination block. We must
1607 * quiesce before we can do the removal.
1608 */
1609 m = get_next_mapping(pool);
1610 m->tc = tc;
1611 m->maybe_shared = maybe_shared;
1612 m->virt_begin = virt_begin;
1613 m->virt_end = virt_end;
1614 m->data_block = data_begin;
1615 m->cell = data_cell;
1616 m->bio = bio;
1617
1618 /*
1619 * The parent bio must not complete before sub discard bios are
1620 * chained to it (see end_discard's bio_chain)!
1621 *
1622 * This per-mapping bi_remaining increment is paired with
1623 * the implicit decrement that occurs via bio_endio() in
1624 * end_discard().
1625 */
1626 bio_inc_remaining(bio);
1627 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1628 pool->process_prepared_discard(m);
1629
1630 begin = virt_end;
1631 }
1632}
1633
1634static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1635{
1636 struct bio *bio = virt_cell->holder;
1637 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1638
1639 /*
1640 * The virt_cell will only get freed once the origin bio completes.
1641 * This means it will remain locked while all the individual
1642 * passdown bios are in flight.
1643 */
1644 h->cell = virt_cell;
1645 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1646
1647 /*
1648 * We complete the bio now, knowing that the bi_remaining field
1649 * will prevent completion until the sub range discards have
1650 * completed.
1651 */
1652 bio_endio(bio);
1653}
1654
1655static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1656{
1657 dm_block_t begin, end;
1658 struct dm_cell_key virt_key;
1659 struct dm_bio_prison_cell *virt_cell;
1660
1661 get_bio_block_range(tc, bio, &begin, &end);
1662 if (begin == end) {
1663 /*
1664 * The discard covers less than a block.
1665 */
1666 bio_endio(bio);
1667 return;
1668 }
1669
1670 build_key(tc->td, VIRTUAL, begin, end, &virt_key);
1671 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell))
1672 /*
1673 * Potential starvation issue: We're relying on the
1674 * fs/application being well behaved, and not trying to
1675 * send IO to a region at the same time as discarding it.
1676 * If they do this persistently then it's possible this
1677 * cell will never be granted.
1678 */
1679 return;
1680
1681 tc->pool->process_discard_cell(tc, virt_cell);
1682}
1683
1684static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1685 struct dm_cell_key *key,
1686 struct dm_thin_lookup_result *lookup_result,
1687 struct dm_bio_prison_cell *cell)
1688{
1689 int r;
1690 dm_block_t data_block;
1691 struct pool *pool = tc->pool;
1692
1693 r = alloc_data_block(tc, &data_block);
1694 switch (r) {
1695 case 0:
1696 schedule_internal_copy(tc, block, lookup_result->block,
1697 data_block, cell, bio);
1698 break;
1699
1700 case -ENOSPC:
1701 retry_bios_on_resume(pool, cell);
1702 break;
1703
1704 default:
1705 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1706 __func__, r);
1707 cell_error(pool, cell);
1708 break;
1709 }
1710}
1711
1712static void __remap_and_issue_shared_cell(void *context,
1713 struct dm_bio_prison_cell *cell)
1714{
1715 struct remap_info *info = context;
1716 struct bio *bio;
1717
1718 while ((bio = bio_list_pop(&cell->bios))) {
1719 if ((bio_data_dir(bio) == WRITE) ||
1720 (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA) ||
1721 bio_op(bio) == REQ_OP_DISCARD))
1722 bio_list_add(&info->defer_bios, bio);
1723 else {
1724 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));;
1725
1726 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1727 inc_all_io_entry(info->tc->pool, bio);
1728 bio_list_add(&info->issue_bios, bio);
1729 }
1730 }
1731}
1732
1733static void remap_and_issue_shared_cell(struct thin_c *tc,
1734 struct dm_bio_prison_cell *cell,
1735 dm_block_t block)
1736{
1737 struct bio *bio;
1738 struct remap_info info;
1739
1740 info.tc = tc;
1741 bio_list_init(&info.defer_bios);
1742 bio_list_init(&info.issue_bios);
1743
1744 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1745 &info, cell);
1746
1747 while ((bio = bio_list_pop(&info.defer_bios)))
1748 thin_defer_bio(tc, bio);
1749
1750 while ((bio = bio_list_pop(&info.issue_bios)))
1751 remap_and_issue(tc, bio, block);
1752}
1753
1754static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1755 dm_block_t block,
1756 struct dm_thin_lookup_result *lookup_result,
1757 struct dm_bio_prison_cell *virt_cell)
1758{
1759 struct dm_bio_prison_cell *data_cell;
1760 struct pool *pool = tc->pool;
1761 struct dm_cell_key key;
1762
1763 /*
1764 * If cell is already occupied, then sharing is already in the process
1765 * of being broken so we have nothing further to do here.
1766 */
1767 build_data_key(tc->td, lookup_result->block, &key);
1768 if (bio_detain(pool, &key, bio, &data_cell)) {
1769 cell_defer_no_holder(tc, virt_cell);
1770 return;
1771 }
1772
1773 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1774 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1775 cell_defer_no_holder(tc, virt_cell);
1776 } else {
1777 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1778
1779 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1780 inc_all_io_entry(pool, bio);
1781 remap_and_issue(tc, bio, lookup_result->block);
1782
1783 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1784 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1785 }
1786}
1787
1788static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1789 struct dm_bio_prison_cell *cell)
1790{
1791 int r;
1792 dm_block_t data_block;
1793 struct pool *pool = tc->pool;
1794
1795 /*
1796 * Remap empty bios (flushes) immediately, without provisioning.
1797 */
1798 if (!bio->bi_iter.bi_size) {
1799 inc_all_io_entry(pool, bio);
1800 cell_defer_no_holder(tc, cell);
1801
1802 remap_and_issue(tc, bio, 0);
1803 return;
1804 }
1805
1806 /*
1807 * Fill read bios with zeroes and complete them immediately.
1808 */
1809 if (bio_data_dir(bio) == READ) {
1810 zero_fill_bio(bio);
1811 cell_defer_no_holder(tc, cell);
1812 bio_endio(bio);
1813 return;
1814 }
1815
1816 r = alloc_data_block(tc, &data_block);
1817 switch (r) {
1818 case 0:
1819 if (tc->origin_dev)
1820 schedule_external_copy(tc, block, data_block, cell, bio);
1821 else
1822 schedule_zero(tc, block, data_block, cell, bio);
1823 break;
1824
1825 case -ENOSPC:
1826 retry_bios_on_resume(pool, cell);
1827 break;
1828
1829 default:
1830 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1831 __func__, r);
1832 cell_error(pool, cell);
1833 break;
1834 }
1835}
1836
1837static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1838{
1839 int r;
1840 struct pool *pool = tc->pool;
1841 struct bio *bio = cell->holder;
1842 dm_block_t block = get_bio_block(tc, bio);
1843 struct dm_thin_lookup_result lookup_result;
1844
1845 if (tc->requeue_mode) {
1846 cell_requeue(pool, cell);
1847 return;
1848 }
1849
1850 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1851 switch (r) {
1852 case 0:
1853 if (lookup_result.shared)
1854 process_shared_bio(tc, bio, block, &lookup_result, cell);
1855 else {
1856 inc_all_io_entry(pool, bio);
1857 remap_and_issue(tc, bio, lookup_result.block);
1858 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1859 }
1860 break;
1861
1862 case -ENODATA:
1863 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1864 inc_all_io_entry(pool, bio);
1865 cell_defer_no_holder(tc, cell);
1866
1867 if (bio_end_sector(bio) <= tc->origin_size)
1868 remap_to_origin_and_issue(tc, bio);
1869
1870 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1871 zero_fill_bio(bio);
1872 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1873 remap_to_origin_and_issue(tc, bio);
1874
1875 } else {
1876 zero_fill_bio(bio);
1877 bio_endio(bio);
1878 }
1879 } else
1880 provision_block(tc, bio, block, cell);
1881 break;
1882
1883 default:
1884 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1885 __func__, r);
1886 cell_defer_no_holder(tc, cell);
1887 bio_io_error(bio);
1888 break;
1889 }
1890}
1891
1892static void process_bio(struct thin_c *tc, struct bio *bio)
1893{
1894 struct pool *pool = tc->pool;
1895 dm_block_t block = get_bio_block(tc, bio);
1896 struct dm_bio_prison_cell *cell;
1897 struct dm_cell_key key;
1898
1899 /*
1900 * If cell is already occupied, then the block is already
1901 * being provisioned so we have nothing further to do here.
1902 */
1903 build_virtual_key(tc->td, block, &key);
1904 if (bio_detain(pool, &key, bio, &cell))
1905 return;
1906
1907 process_cell(tc, cell);
1908}
1909
1910static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
1911 struct dm_bio_prison_cell *cell)
1912{
1913 int r;
1914 int rw = bio_data_dir(bio);
1915 dm_block_t block = get_bio_block(tc, bio);
1916 struct dm_thin_lookup_result lookup_result;
1917
1918 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1919 switch (r) {
1920 case 0:
1921 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
1922 handle_unserviceable_bio(tc->pool, bio);
1923 if (cell)
1924 cell_defer_no_holder(tc, cell);
1925 } else {
1926 inc_all_io_entry(tc->pool, bio);
1927 remap_and_issue(tc, bio, lookup_result.block);
1928 if (cell)
1929 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1930 }
1931 break;
1932
1933 case -ENODATA:
1934 if (cell)
1935 cell_defer_no_holder(tc, cell);
1936 if (rw != READ) {
1937 handle_unserviceable_bio(tc->pool, bio);
1938 break;
1939 }
1940
1941 if (tc->origin_dev) {
1942 inc_all_io_entry(tc->pool, bio);
1943 remap_to_origin_and_issue(tc, bio);
1944 break;
1945 }
1946
1947 zero_fill_bio(bio);
1948 bio_endio(bio);
1949 break;
1950
1951 default:
1952 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1953 __func__, r);
1954 if (cell)
1955 cell_defer_no_holder(tc, cell);
1956 bio_io_error(bio);
1957 break;
1958 }
1959}
1960
1961static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1962{
1963 __process_bio_read_only(tc, bio, NULL);
1964}
1965
1966static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1967{
1968 __process_bio_read_only(tc, cell->holder, cell);
1969}
1970
1971static void process_bio_success(struct thin_c *tc, struct bio *bio)
1972{
1973 bio_endio(bio);
1974}
1975
1976static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1977{
1978 bio_io_error(bio);
1979}
1980
1981static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1982{
1983 cell_success(tc->pool, cell);
1984}
1985
1986static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1987{
1988 cell_error(tc->pool, cell);
1989}
1990
1991/*
1992 * FIXME: should we also commit due to size of transaction, measured in
1993 * metadata blocks?
1994 */
1995static int need_commit_due_to_time(struct pool *pool)
1996{
1997 return !time_in_range(jiffies, pool->last_commit_jiffies,
1998 pool->last_commit_jiffies + COMMIT_PERIOD);
1999}
2000
2001#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2002#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2003
2004static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2005{
2006 struct rb_node **rbp, *parent;
2007 struct dm_thin_endio_hook *pbd;
2008 sector_t bi_sector = bio->bi_iter.bi_sector;
2009
2010 rbp = &tc->sort_bio_list.rb_node;
2011 parent = NULL;
2012 while (*rbp) {
2013 parent = *rbp;
2014 pbd = thin_pbd(parent);
2015
2016 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2017 rbp = &(*rbp)->rb_left;
2018 else
2019 rbp = &(*rbp)->rb_right;
2020 }
2021
2022 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2023 rb_link_node(&pbd->rb_node, parent, rbp);
2024 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2025}
2026
2027static void __extract_sorted_bios(struct thin_c *tc)
2028{
2029 struct rb_node *node;
2030 struct dm_thin_endio_hook *pbd;
2031 struct bio *bio;
2032
2033 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2034 pbd = thin_pbd(node);
2035 bio = thin_bio(pbd);
2036
2037 bio_list_add(&tc->deferred_bio_list, bio);
2038 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2039 }
2040
2041 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2042}
2043
2044static void __sort_thin_deferred_bios(struct thin_c *tc)
2045{
2046 struct bio *bio;
2047 struct bio_list bios;
2048
2049 bio_list_init(&bios);
2050 bio_list_merge(&bios, &tc->deferred_bio_list);
2051 bio_list_init(&tc->deferred_bio_list);
2052
2053 /* Sort deferred_bio_list using rb-tree */
2054 while ((bio = bio_list_pop(&bios)))
2055 __thin_bio_rb_add(tc, bio);
2056
2057 /*
2058 * Transfer the sorted bios in sort_bio_list back to
2059 * deferred_bio_list to allow lockless submission of
2060 * all bios.
2061 */
2062 __extract_sorted_bios(tc);
2063}
2064
2065static void process_thin_deferred_bios(struct thin_c *tc)
2066{
2067 struct pool *pool = tc->pool;
2068 unsigned long flags;
2069 struct bio *bio;
2070 struct bio_list bios;
2071 struct blk_plug plug;
2072 unsigned count = 0;
2073
2074 if (tc->requeue_mode) {
2075 error_thin_bio_list(tc, &tc->deferred_bio_list, DM_ENDIO_REQUEUE);
2076 return;
2077 }
2078
2079 bio_list_init(&bios);
2080
2081 spin_lock_irqsave(&tc->lock, flags);
2082
2083 if (bio_list_empty(&tc->deferred_bio_list)) {
2084 spin_unlock_irqrestore(&tc->lock, flags);
2085 return;
2086 }
2087
2088 __sort_thin_deferred_bios(tc);
2089
2090 bio_list_merge(&bios, &tc->deferred_bio_list);
2091 bio_list_init(&tc->deferred_bio_list);
2092
2093 spin_unlock_irqrestore(&tc->lock, flags);
2094
2095 blk_start_plug(&plug);
2096 while ((bio = bio_list_pop(&bios))) {
2097 /*
2098 * If we've got no free new_mapping structs, and processing
2099 * this bio might require one, we pause until there are some
2100 * prepared mappings to process.
2101 */
2102 if (ensure_next_mapping(pool)) {
2103 spin_lock_irqsave(&tc->lock, flags);
2104 bio_list_add(&tc->deferred_bio_list, bio);
2105 bio_list_merge(&tc->deferred_bio_list, &bios);
2106 spin_unlock_irqrestore(&tc->lock, flags);
2107 break;
2108 }
2109
2110 if (bio_op(bio) == REQ_OP_DISCARD)
2111 pool->process_discard(tc, bio);
2112 else
2113 pool->process_bio(tc, bio);
2114
2115 if ((count++ & 127) == 0) {
2116 throttle_work_update(&pool->throttle);
2117 dm_pool_issue_prefetches(pool->pmd);
2118 }
2119 }
2120 blk_finish_plug(&plug);
2121}
2122
2123static int cmp_cells(const void *lhs, const void *rhs)
2124{
2125 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2126 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2127
2128 BUG_ON(!lhs_cell->holder);
2129 BUG_ON(!rhs_cell->holder);
2130
2131 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2132 return -1;
2133
2134 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2135 return 1;
2136
2137 return 0;
2138}
2139
2140static unsigned sort_cells(struct pool *pool, struct list_head *cells)
2141{
2142 unsigned count = 0;
2143 struct dm_bio_prison_cell *cell, *tmp;
2144
2145 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2146 if (count >= CELL_SORT_ARRAY_SIZE)
2147 break;
2148
2149 pool->cell_sort_array[count++] = cell;
2150 list_del(&cell->user_list);
2151 }
2152
2153 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2154
2155 return count;
2156}
2157
2158static void process_thin_deferred_cells(struct thin_c *tc)
2159{
2160 struct pool *pool = tc->pool;
2161 unsigned long flags;
2162 struct list_head cells;
2163 struct dm_bio_prison_cell *cell;
2164 unsigned i, j, count;
2165
2166 INIT_LIST_HEAD(&cells);
2167
2168 spin_lock_irqsave(&tc->lock, flags);
2169 list_splice_init(&tc->deferred_cells, &cells);
2170 spin_unlock_irqrestore(&tc->lock, flags);
2171
2172 if (list_empty(&cells))
2173 return;
2174
2175 do {
2176 count = sort_cells(tc->pool, &cells);
2177
2178 for (i = 0; i < count; i++) {
2179 cell = pool->cell_sort_array[i];
2180 BUG_ON(!cell->holder);
2181
2182 /*
2183 * If we've got no free new_mapping structs, and processing
2184 * this bio might require one, we pause until there are some
2185 * prepared mappings to process.
2186 */
2187 if (ensure_next_mapping(pool)) {
2188 for (j = i; j < count; j++)
2189 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2190
2191 spin_lock_irqsave(&tc->lock, flags);
2192 list_splice(&cells, &tc->deferred_cells);
2193 spin_unlock_irqrestore(&tc->lock, flags);
2194 return;
2195 }
2196
2197 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2198 pool->process_discard_cell(tc, cell);
2199 else
2200 pool->process_cell(tc, cell);
2201 }
2202 } while (!list_empty(&cells));
2203}
2204
2205static void thin_get(struct thin_c *tc);
2206static void thin_put(struct thin_c *tc);
2207
2208/*
2209 * We can't hold rcu_read_lock() around code that can block. So we
2210 * find a thin with the rcu lock held; bump a refcount; then drop
2211 * the lock.
2212 */
2213static struct thin_c *get_first_thin(struct pool *pool)
2214{
2215 struct thin_c *tc = NULL;
2216
2217 rcu_read_lock();
2218 if (!list_empty(&pool->active_thins)) {
2219 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
2220 thin_get(tc);
2221 }
2222 rcu_read_unlock();
2223
2224 return tc;
2225}
2226
2227static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2228{
2229 struct thin_c *old_tc = tc;
2230
2231 rcu_read_lock();
2232 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2233 thin_get(tc);
2234 thin_put(old_tc);
2235 rcu_read_unlock();
2236 return tc;
2237 }
2238 thin_put(old_tc);
2239 rcu_read_unlock();
2240
2241 return NULL;
2242}
2243
2244static void process_deferred_bios(struct pool *pool)
2245{
2246 unsigned long flags;
2247 struct bio *bio;
2248 struct bio_list bios;
2249 struct thin_c *tc;
2250
2251 tc = get_first_thin(pool);
2252 while (tc) {
2253 process_thin_deferred_cells(tc);
2254 process_thin_deferred_bios(tc);
2255 tc = get_next_thin(pool, tc);
2256 }
2257
2258 /*
2259 * If there are any deferred flush bios, we must commit
2260 * the metadata before issuing them.
2261 */
2262 bio_list_init(&bios);
2263 spin_lock_irqsave(&pool->lock, flags);
2264 bio_list_merge(&bios, &pool->deferred_flush_bios);
2265 bio_list_init(&pool->deferred_flush_bios);
2266 spin_unlock_irqrestore(&pool->lock, flags);
2267
2268 if (bio_list_empty(&bios) &&
2269 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2270 return;
2271
2272 if (commit(pool)) {
2273 while ((bio = bio_list_pop(&bios)))
2274 bio_io_error(bio);
2275 return;
2276 }
2277 pool->last_commit_jiffies = jiffies;
2278
2279 while ((bio = bio_list_pop(&bios)))
2280 generic_make_request(bio);
2281}
2282
2283static void do_worker(struct work_struct *ws)
2284{
2285 struct pool *pool = container_of(ws, struct pool, worker);
2286
2287 throttle_work_start(&pool->throttle);
2288 dm_pool_issue_prefetches(pool->pmd);
2289 throttle_work_update(&pool->throttle);
2290 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2291 throttle_work_update(&pool->throttle);
2292 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2293 throttle_work_update(&pool->throttle);
2294 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2295 throttle_work_update(&pool->throttle);
2296 process_deferred_bios(pool);
2297 throttle_work_complete(&pool->throttle);
2298}
2299
2300/*
2301 * We want to commit periodically so that not too much
2302 * unwritten data builds up.
2303 */
2304static void do_waker(struct work_struct *ws)
2305{
2306 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2307 wake_worker(pool);
2308 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2309}
2310
2311static void notify_of_pool_mode_change_to_oods(struct pool *pool);
2312
2313/*
2314 * We're holding onto IO to allow userland time to react. After the
2315 * timeout either the pool will have been resized (and thus back in
2316 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2317 */
2318static void do_no_space_timeout(struct work_struct *ws)
2319{
2320 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2321 no_space_timeout);
2322
2323 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2324 pool->pf.error_if_no_space = true;
2325 notify_of_pool_mode_change_to_oods(pool);
2326 error_retry_list_with_code(pool, -ENOSPC);
2327 }
2328}
2329
2330/*----------------------------------------------------------------*/
2331
2332struct pool_work {
2333 struct work_struct worker;
2334 struct completion complete;
2335};
2336
2337static struct pool_work *to_pool_work(struct work_struct *ws)
2338{
2339 return container_of(ws, struct pool_work, worker);
2340}
2341
2342static void pool_work_complete(struct pool_work *pw)
2343{
2344 complete(&pw->complete);
2345}
2346
2347static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2348 void (*fn)(struct work_struct *))
2349{
2350 INIT_WORK_ONSTACK(&pw->worker, fn);
2351 init_completion(&pw->complete);
2352 queue_work(pool->wq, &pw->worker);
2353 wait_for_completion(&pw->complete);
2354}
2355
2356/*----------------------------------------------------------------*/
2357
2358struct noflush_work {
2359 struct pool_work pw;
2360 struct thin_c *tc;
2361};
2362
2363static struct noflush_work *to_noflush(struct work_struct *ws)
2364{
2365 return container_of(to_pool_work(ws), struct noflush_work, pw);
2366}
2367
2368static void do_noflush_start(struct work_struct *ws)
2369{
2370 struct noflush_work *w = to_noflush(ws);
2371 w->tc->requeue_mode = true;
2372 requeue_io(w->tc);
2373 pool_work_complete(&w->pw);
2374}
2375
2376static void do_noflush_stop(struct work_struct *ws)
2377{
2378 struct noflush_work *w = to_noflush(ws);
2379 w->tc->requeue_mode = false;
2380 pool_work_complete(&w->pw);
2381}
2382
2383static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2384{
2385 struct noflush_work w;
2386
2387 w.tc = tc;
2388 pool_work_wait(&w.pw, tc->pool, fn);
2389}
2390
2391/*----------------------------------------------------------------*/
2392
2393static enum pool_mode get_pool_mode(struct pool *pool)
2394{
2395 return pool->pf.mode;
2396}
2397
2398static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
2399{
2400 dm_table_event(pool->ti->table);
2401 DMINFO("%s: switching pool to %s mode",
2402 dm_device_name(pool->pool_md), new_mode);
2403}
2404
2405static void notify_of_pool_mode_change_to_oods(struct pool *pool)
2406{
2407 if (!pool->pf.error_if_no_space)
2408 notify_of_pool_mode_change(pool, "out-of-data-space (queue IO)");
2409 else
2410 notify_of_pool_mode_change(pool, "out-of-data-space (error IO)");
2411}
2412
2413static bool passdown_enabled(struct pool_c *pt)
2414{
2415 return pt->adjusted_pf.discard_passdown;
2416}
2417
2418static void set_discard_callbacks(struct pool *pool)
2419{
2420 struct pool_c *pt = pool->ti->private;
2421
2422 if (passdown_enabled(pt)) {
2423 pool->process_discard_cell = process_discard_cell_passdown;
2424 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2425 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2426 } else {
2427 pool->process_discard_cell = process_discard_cell_no_passdown;
2428 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2429 }
2430}
2431
2432static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2433{
2434 struct pool_c *pt = pool->ti->private;
2435 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2436 enum pool_mode old_mode = get_pool_mode(pool);
2437 unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
2438
2439 /*
2440 * Never allow the pool to transition to PM_WRITE mode if user
2441 * intervention is required to verify metadata and data consistency.
2442 */
2443 if (new_mode == PM_WRITE && needs_check) {
2444 DMERR("%s: unable to switch pool to write mode until repaired.",
2445 dm_device_name(pool->pool_md));
2446 if (old_mode != new_mode)
2447 new_mode = old_mode;
2448 else
2449 new_mode = PM_READ_ONLY;
2450 }
2451 /*
2452 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2453 * not going to recover without a thin_repair. So we never let the
2454 * pool move out of the old mode.
2455 */
2456 if (old_mode == PM_FAIL)
2457 new_mode = old_mode;
2458
2459 switch (new_mode) {
2460 case PM_FAIL:
2461 if (old_mode != new_mode)
2462 notify_of_pool_mode_change(pool, "failure");
2463 dm_pool_metadata_read_only(pool->pmd);
2464 pool->process_bio = process_bio_fail;
2465 pool->process_discard = process_bio_fail;
2466 pool->process_cell = process_cell_fail;
2467 pool->process_discard_cell = process_cell_fail;
2468 pool->process_prepared_mapping = process_prepared_mapping_fail;
2469 pool->process_prepared_discard = process_prepared_discard_fail;
2470
2471 error_retry_list(pool);
2472 break;
2473
2474 case PM_READ_ONLY:
2475 if (old_mode != new_mode)
2476 notify_of_pool_mode_change(pool, "read-only");
2477 dm_pool_metadata_read_only(pool->pmd);
2478 pool->process_bio = process_bio_read_only;
2479 pool->process_discard = process_bio_success;
2480 pool->process_cell = process_cell_read_only;
2481 pool->process_discard_cell = process_cell_success;
2482 pool->process_prepared_mapping = process_prepared_mapping_fail;
2483 pool->process_prepared_discard = process_prepared_discard_success;
2484
2485 error_retry_list(pool);
2486 break;
2487
2488 case PM_OUT_OF_DATA_SPACE:
2489 /*
2490 * Ideally we'd never hit this state; the low water mark
2491 * would trigger userland to extend the pool before we
2492 * completely run out of data space. However, many small
2493 * IOs to unprovisioned space can consume data space at an
2494 * alarming rate. Adjust your low water mark if you're
2495 * frequently seeing this mode.
2496 */
2497 if (old_mode != new_mode)
2498 notify_of_pool_mode_change_to_oods(pool);
2499 pool->out_of_data_space = true;
2500 pool->process_bio = process_bio_read_only;
2501 pool->process_discard = process_discard_bio;
2502 pool->process_cell = process_cell_read_only;
2503 pool->process_prepared_mapping = process_prepared_mapping;
2504 set_discard_callbacks(pool);
2505
2506 if (!pool->pf.error_if_no_space && no_space_timeout)
2507 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2508 break;
2509
2510 case PM_WRITE:
2511 if (old_mode != new_mode)
2512 notify_of_pool_mode_change(pool, "write");
2513 pool->out_of_data_space = false;
2514 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2515 dm_pool_metadata_read_write(pool->pmd);
2516 pool->process_bio = process_bio;
2517 pool->process_discard = process_discard_bio;
2518 pool->process_cell = process_cell;
2519 pool->process_prepared_mapping = process_prepared_mapping;
2520 set_discard_callbacks(pool);
2521 break;
2522 }
2523
2524 pool->pf.mode = new_mode;
2525 /*
2526 * The pool mode may have changed, sync it so bind_control_target()
2527 * doesn't cause an unexpected mode transition on resume.
2528 */
2529 pt->adjusted_pf.mode = new_mode;
2530}
2531
2532static void abort_transaction(struct pool *pool)
2533{
2534 const char *dev_name = dm_device_name(pool->pool_md);
2535
2536 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2537 if (dm_pool_abort_metadata(pool->pmd)) {
2538 DMERR("%s: failed to abort metadata transaction", dev_name);
2539 set_pool_mode(pool, PM_FAIL);
2540 }
2541
2542 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2543 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2544 set_pool_mode(pool, PM_FAIL);
2545 }
2546}
2547
2548static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2549{
2550 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2551 dm_device_name(pool->pool_md), op, r);
2552
2553 abort_transaction(pool);
2554 set_pool_mode(pool, PM_READ_ONLY);
2555}
2556
2557/*----------------------------------------------------------------*/
2558
2559/*
2560 * Mapping functions.
2561 */
2562
2563/*
2564 * Called only while mapping a thin bio to hand it over to the workqueue.
2565 */
2566static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2567{
2568 unsigned long flags;
2569 struct pool *pool = tc->pool;
2570
2571 spin_lock_irqsave(&tc->lock, flags);
2572 bio_list_add(&tc->deferred_bio_list, bio);
2573 spin_unlock_irqrestore(&tc->lock, flags);
2574
2575 wake_worker(pool);
2576}
2577
2578static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2579{
2580 struct pool *pool = tc->pool;
2581
2582 throttle_lock(&pool->throttle);
2583 thin_defer_bio(tc, bio);
2584 throttle_unlock(&pool->throttle);
2585}
2586
2587static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2588{
2589 unsigned long flags;
2590 struct pool *pool = tc->pool;
2591
2592 throttle_lock(&pool->throttle);
2593 spin_lock_irqsave(&tc->lock, flags);
2594 list_add_tail(&cell->user_list, &tc->deferred_cells);
2595 spin_unlock_irqrestore(&tc->lock, flags);
2596 throttle_unlock(&pool->throttle);
2597
2598 wake_worker(pool);
2599}
2600
2601static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2602{
2603 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2604
2605 h->tc = tc;
2606 h->shared_read_entry = NULL;
2607 h->all_io_entry = NULL;
2608 h->overwrite_mapping = NULL;
2609 h->cell = NULL;
2610}
2611
2612/*
2613 * Non-blocking function called from the thin target's map function.
2614 */
2615static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2616{
2617 int r;
2618 struct thin_c *tc = ti->private;
2619 dm_block_t block = get_bio_block(tc, bio);
2620 struct dm_thin_device *td = tc->td;
2621 struct dm_thin_lookup_result result;
2622 struct dm_bio_prison_cell *virt_cell, *data_cell;
2623 struct dm_cell_key key;
2624
2625 thin_hook_bio(tc, bio);
2626
2627 if (tc->requeue_mode) {
2628 bio->bi_error = DM_ENDIO_REQUEUE;
2629 bio_endio(bio);
2630 return DM_MAPIO_SUBMITTED;
2631 }
2632
2633 if (get_pool_mode(tc->pool) == PM_FAIL) {
2634 bio_io_error(bio);
2635 return DM_MAPIO_SUBMITTED;
2636 }
2637
2638 if (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA) ||
2639 bio_op(bio) == REQ_OP_DISCARD) {
2640 thin_defer_bio_with_throttle(tc, bio);
2641 return DM_MAPIO_SUBMITTED;
2642 }
2643
2644 /*
2645 * We must hold the virtual cell before doing the lookup, otherwise
2646 * there's a race with discard.
2647 */
2648 build_virtual_key(tc->td, block, &key);
2649 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2650 return DM_MAPIO_SUBMITTED;
2651
2652 r = dm_thin_find_block(td, block, 0, &result);
2653
2654 /*
2655 * Note that we defer readahead too.
2656 */
2657 switch (r) {
2658 case 0:
2659 if (unlikely(result.shared)) {
2660 /*
2661 * We have a race condition here between the
2662 * result.shared value returned by the lookup and
2663 * snapshot creation, which may cause new
2664 * sharing.
2665 *
2666 * To avoid this always quiesce the origin before
2667 * taking the snap. You want to do this anyway to
2668 * ensure a consistent application view
2669 * (i.e. lockfs).
2670 *
2671 * More distant ancestors are irrelevant. The
2672 * shared flag will be set in their case.
2673 */
2674 thin_defer_cell(tc, virt_cell);
2675 return DM_MAPIO_SUBMITTED;
2676 }
2677
2678 build_data_key(tc->td, result.block, &key);
2679 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2680 cell_defer_no_holder(tc, virt_cell);
2681 return DM_MAPIO_SUBMITTED;
2682 }
2683
2684 inc_all_io_entry(tc->pool, bio);
2685 cell_defer_no_holder(tc, data_cell);
2686 cell_defer_no_holder(tc, virt_cell);
2687
2688 remap(tc, bio, result.block);
2689 return DM_MAPIO_REMAPPED;
2690
2691 case -ENODATA:
2692 case -EWOULDBLOCK:
2693 thin_defer_cell(tc, virt_cell);
2694 return DM_MAPIO_SUBMITTED;
2695
2696 default:
2697 /*
2698 * Must always call bio_io_error on failure.
2699 * dm_thin_find_block can fail with -EINVAL if the
2700 * pool is switched to fail-io mode.
2701 */
2702 bio_io_error(bio);
2703 cell_defer_no_holder(tc, virt_cell);
2704 return DM_MAPIO_SUBMITTED;
2705 }
2706}
2707
2708static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
2709{
2710 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
2711 struct request_queue *q;
2712
2713 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
2714 return 1;
2715
2716 q = bdev_get_queue(pt->data_dev->bdev);
2717 return bdi_congested(&q->backing_dev_info, bdi_bits);
2718}
2719
2720static void requeue_bios(struct pool *pool)
2721{
2722 unsigned long flags;
2723 struct thin_c *tc;
2724
2725 rcu_read_lock();
2726 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2727 spin_lock_irqsave(&tc->lock, flags);
2728 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2729 bio_list_init(&tc->retry_on_resume_list);
2730 spin_unlock_irqrestore(&tc->lock, flags);
2731 }
2732 rcu_read_unlock();
2733}
2734
2735/*----------------------------------------------------------------
2736 * Binding of control targets to a pool object
2737 *--------------------------------------------------------------*/
2738static bool data_dev_supports_discard(struct pool_c *pt)
2739{
2740 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
2741
2742 return q && blk_queue_discard(q);
2743}
2744
2745static bool is_factor(sector_t block_size, uint32_t n)
2746{
2747 return !sector_div(block_size, n);
2748}
2749
2750/*
2751 * If discard_passdown was enabled verify that the data device
2752 * supports discards. Disable discard_passdown if not.
2753 */
2754static void disable_passdown_if_not_supported(struct pool_c *pt)
2755{
2756 struct pool *pool = pt->pool;
2757 struct block_device *data_bdev = pt->data_dev->bdev;
2758 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2759 const char *reason = NULL;
2760 char buf[BDEVNAME_SIZE];
2761
2762 if (!pt->adjusted_pf.discard_passdown)
2763 return;
2764
2765 if (!data_dev_supports_discard(pt))
2766 reason = "discard unsupported";
2767
2768 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2769 reason = "max discard sectors smaller than a block";
2770
2771 if (reason) {
2772 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
2773 pt->adjusted_pf.discard_passdown = false;
2774 }
2775}
2776
2777static int bind_control_target(struct pool *pool, struct dm_target *ti)
2778{
2779 struct pool_c *pt = ti->private;
2780
2781 /*
2782 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2783 */
2784 enum pool_mode old_mode = get_pool_mode(pool);
2785 enum pool_mode new_mode = pt->adjusted_pf.mode;
2786
2787 /*
2788 * Don't change the pool's mode until set_pool_mode() below.
2789 * Otherwise the pool's process_* function pointers may
2790 * not match the desired pool mode.
2791 */
2792 pt->adjusted_pf.mode = old_mode;
2793
2794 pool->ti = ti;
2795 pool->pf = pt->adjusted_pf;
2796 pool->low_water_blocks = pt->low_water_blocks;
2797
2798 set_pool_mode(pool, new_mode);
2799
2800 return 0;
2801}
2802
2803static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2804{
2805 if (pool->ti == ti)
2806 pool->ti = NULL;
2807}
2808
2809/*----------------------------------------------------------------
2810 * Pool creation
2811 *--------------------------------------------------------------*/
2812/* Initialize pool features. */
2813static void pool_features_init(struct pool_features *pf)
2814{
2815 pf->mode = PM_WRITE;
2816 pf->zero_new_blocks = true;
2817 pf->discard_enabled = true;
2818 pf->discard_passdown = true;
2819 pf->error_if_no_space = false;
2820}
2821
2822static void __pool_destroy(struct pool *pool)
2823{
2824 __pool_table_remove(pool);
2825
2826 vfree(pool->cell_sort_array);
2827 if (dm_pool_metadata_close(pool->pmd) < 0)
2828 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2829
2830 dm_bio_prison_destroy(pool->prison);
2831 dm_kcopyd_client_destroy(pool->copier);
2832
2833 if (pool->wq)
2834 destroy_workqueue(pool->wq);
2835
2836 if (pool->next_mapping)
2837 mempool_free(pool->next_mapping, pool->mapping_pool);
2838 mempool_destroy(pool->mapping_pool);
2839 dm_deferred_set_destroy(pool->shared_read_ds);
2840 dm_deferred_set_destroy(pool->all_io_ds);
2841 kfree(pool);
2842}
2843
2844static struct kmem_cache *_new_mapping_cache;
2845
2846static struct pool *pool_create(struct mapped_device *pool_md,
2847 struct block_device *metadata_dev,
2848 unsigned long block_size,
2849 int read_only, char **error)
2850{
2851 int r;
2852 void *err_p;
2853 struct pool *pool;
2854 struct dm_pool_metadata *pmd;
2855 bool format_device = read_only ? false : true;
2856
2857 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2858 if (IS_ERR(pmd)) {
2859 *error = "Error creating metadata object";
2860 return (struct pool *)pmd;
2861 }
2862
2863 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
2864 if (!pool) {
2865 *error = "Error allocating memory for pool";
2866 err_p = ERR_PTR(-ENOMEM);
2867 goto bad_pool;
2868 }
2869
2870 pool->pmd = pmd;
2871 pool->sectors_per_block = block_size;
2872 if (block_size & (block_size - 1))
2873 pool->sectors_per_block_shift = -1;
2874 else
2875 pool->sectors_per_block_shift = __ffs(block_size);
2876 pool->low_water_blocks = 0;
2877 pool_features_init(&pool->pf);
2878 pool->prison = dm_bio_prison_create();
2879 if (!pool->prison) {
2880 *error = "Error creating pool's bio prison";
2881 err_p = ERR_PTR(-ENOMEM);
2882 goto bad_prison;
2883 }
2884
2885 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2886 if (IS_ERR(pool->copier)) {
2887 r = PTR_ERR(pool->copier);
2888 *error = "Error creating pool's kcopyd client";
2889 err_p = ERR_PTR(r);
2890 goto bad_kcopyd_client;
2891 }
2892
2893 /*
2894 * Create singlethreaded workqueue that will service all devices
2895 * that use this metadata.
2896 */
2897 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2898 if (!pool->wq) {
2899 *error = "Error creating pool's workqueue";
2900 err_p = ERR_PTR(-ENOMEM);
2901 goto bad_wq;
2902 }
2903
2904 throttle_init(&pool->throttle);
2905 INIT_WORK(&pool->worker, do_worker);
2906 INIT_DELAYED_WORK(&pool->waker, do_waker);
2907 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2908 spin_lock_init(&pool->lock);
2909 bio_list_init(&pool->deferred_flush_bios);
2910 INIT_LIST_HEAD(&pool->prepared_mappings);
2911 INIT_LIST_HEAD(&pool->prepared_discards);
2912 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
2913 INIT_LIST_HEAD(&pool->active_thins);
2914 pool->low_water_triggered = false;
2915 pool->suspended = true;
2916 pool->out_of_data_space = false;
2917
2918 pool->shared_read_ds = dm_deferred_set_create();
2919 if (!pool->shared_read_ds) {
2920 *error = "Error creating pool's shared read deferred set";
2921 err_p = ERR_PTR(-ENOMEM);
2922 goto bad_shared_read_ds;
2923 }
2924
2925 pool->all_io_ds = dm_deferred_set_create();
2926 if (!pool->all_io_ds) {
2927 *error = "Error creating pool's all io deferred set";
2928 err_p = ERR_PTR(-ENOMEM);
2929 goto bad_all_io_ds;
2930 }
2931
2932 pool->next_mapping = NULL;
2933 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
2934 _new_mapping_cache);
2935 if (!pool->mapping_pool) {
2936 *error = "Error creating pool's mapping mempool";
2937 err_p = ERR_PTR(-ENOMEM);
2938 goto bad_mapping_pool;
2939 }
2940
2941 pool->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE);
2942 if (!pool->cell_sort_array) {
2943 *error = "Error allocating cell sort array";
2944 err_p = ERR_PTR(-ENOMEM);
2945 goto bad_sort_array;
2946 }
2947
2948 pool->ref_count = 1;
2949 pool->last_commit_jiffies = jiffies;
2950 pool->pool_md = pool_md;
2951 pool->md_dev = metadata_dev;
2952 __pool_table_insert(pool);
2953
2954 return pool;
2955
2956bad_sort_array:
2957 mempool_destroy(pool->mapping_pool);
2958bad_mapping_pool:
2959 dm_deferred_set_destroy(pool->all_io_ds);
2960bad_all_io_ds:
2961 dm_deferred_set_destroy(pool->shared_read_ds);
2962bad_shared_read_ds:
2963 destroy_workqueue(pool->wq);
2964bad_wq:
2965 dm_kcopyd_client_destroy(pool->copier);
2966bad_kcopyd_client:
2967 dm_bio_prison_destroy(pool->prison);
2968bad_prison:
2969 kfree(pool);
2970bad_pool:
2971 if (dm_pool_metadata_close(pmd))
2972 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2973
2974 return err_p;
2975}
2976
2977static void __pool_inc(struct pool *pool)
2978{
2979 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2980 pool->ref_count++;
2981}
2982
2983static void __pool_dec(struct pool *pool)
2984{
2985 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2986 BUG_ON(!pool->ref_count);
2987 if (!--pool->ref_count)
2988 __pool_destroy(pool);
2989}
2990
2991static struct pool *__pool_find(struct mapped_device *pool_md,
2992 struct block_device *metadata_dev,
2993 unsigned long block_size, int read_only,
2994 char **error, int *created)
2995{
2996 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
2997
2998 if (pool) {
2999 if (pool->pool_md != pool_md) {
3000 *error = "metadata device already in use by a pool";
3001 return ERR_PTR(-EBUSY);
3002 }
3003 __pool_inc(pool);
3004
3005 } else {
3006 pool = __pool_table_lookup(pool_md);
3007 if (pool) {
3008 if (pool->md_dev != metadata_dev) {
3009 *error = "different pool cannot replace a pool";
3010 return ERR_PTR(-EINVAL);
3011 }
3012 __pool_inc(pool);
3013
3014 } else {
3015 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
3016 *created = 1;
3017 }
3018 }
3019
3020 return pool;
3021}
3022
3023/*----------------------------------------------------------------
3024 * Pool target methods
3025 *--------------------------------------------------------------*/
3026static void pool_dtr(struct dm_target *ti)
3027{
3028 struct pool_c *pt = ti->private;
3029
3030 mutex_lock(&dm_thin_pool_table.mutex);
3031
3032 unbind_control_target(pt->pool, ti);
3033 __pool_dec(pt->pool);
3034 dm_put_device(ti, pt->metadata_dev);
3035 dm_put_device(ti, pt->data_dev);
3036 kfree(pt);
3037
3038 mutex_unlock(&dm_thin_pool_table.mutex);
3039}
3040
3041static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3042 struct dm_target *ti)
3043{
3044 int r;
3045 unsigned argc;
3046 const char *arg_name;
3047
3048 static struct dm_arg _args[] = {
3049 {0, 4, "Invalid number of pool feature arguments"},
3050 };
3051
3052 /*
3053 * No feature arguments supplied.
3054 */
3055 if (!as->argc)
3056 return 0;
3057
3058 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3059 if (r)
3060 return -EINVAL;
3061
3062 while (argc && !r) {
3063 arg_name = dm_shift_arg(as);
3064 argc--;
3065
3066 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3067 pf->zero_new_blocks = false;
3068
3069 else if (!strcasecmp(arg_name, "ignore_discard"))
3070 pf->discard_enabled = false;
3071
3072 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3073 pf->discard_passdown = false;
3074
3075 else if (!strcasecmp(arg_name, "read_only"))
3076 pf->mode = PM_READ_ONLY;
3077
3078 else if (!strcasecmp(arg_name, "error_if_no_space"))
3079 pf->error_if_no_space = true;
3080
3081 else {
3082 ti->error = "Unrecognised pool feature requested";
3083 r = -EINVAL;
3084 break;
3085 }
3086 }
3087
3088 return r;
3089}
3090
3091static void metadata_low_callback(void *context)
3092{
3093 struct pool *pool = context;
3094
3095 DMWARN("%s: reached low water mark for metadata device: sending event.",
3096 dm_device_name(pool->pool_md));
3097
3098 dm_table_event(pool->ti->table);
3099}
3100
3101static sector_t get_dev_size(struct block_device *bdev)
3102{
3103 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
3104}
3105
3106static void warn_if_metadata_device_too_big(struct block_device *bdev)
3107{
3108 sector_t metadata_dev_size = get_dev_size(bdev);
3109 char buffer[BDEVNAME_SIZE];
3110
3111 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3112 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
3113 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
3114}
3115
3116static sector_t get_metadata_dev_size(struct block_device *bdev)
3117{
3118 sector_t metadata_dev_size = get_dev_size(bdev);
3119
3120 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3121 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3122
3123 return metadata_dev_size;
3124}
3125
3126static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3127{
3128 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3129
3130 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3131
3132 return metadata_dev_size;
3133}
3134
3135/*
3136 * When a metadata threshold is crossed a dm event is triggered, and
3137 * userland should respond by growing the metadata device. We could let
3138 * userland set the threshold, like we do with the data threshold, but I'm
3139 * not sure they know enough to do this well.
3140 */
3141static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3142{
3143 /*
3144 * 4M is ample for all ops with the possible exception of thin
3145 * device deletion which is harmless if it fails (just retry the
3146 * delete after you've grown the device).
3147 */
3148 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3149 return min((dm_block_t)1024ULL /* 4M */, quarter);
3150}
3151
3152/*
3153 * thin-pool <metadata dev> <data dev>
3154 * <data block size (sectors)>
3155 * <low water mark (blocks)>
3156 * [<#feature args> [<arg>]*]
3157 *
3158 * Optional feature arguments are:
3159 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3160 * ignore_discard: disable discard
3161 * no_discard_passdown: don't pass discards down to the data device
3162 * read_only: Don't allow any changes to be made to the pool metadata.
3163 * error_if_no_space: error IOs, instead of queueing, if no space.
3164 */
3165static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
3166{
3167 int r, pool_created = 0;
3168 struct pool_c *pt;
3169 struct pool *pool;
3170 struct pool_features pf;
3171 struct dm_arg_set as;
3172 struct dm_dev *data_dev;
3173 unsigned long block_size;
3174 dm_block_t low_water_blocks;
3175 struct dm_dev *metadata_dev;
3176 fmode_t metadata_mode;
3177
3178 /*
3179 * FIXME Remove validation from scope of lock.
3180 */
3181 mutex_lock(&dm_thin_pool_table.mutex);
3182
3183 if (argc < 4) {
3184 ti->error = "Invalid argument count";
3185 r = -EINVAL;
3186 goto out_unlock;
3187 }
3188
3189 as.argc = argc;
3190 as.argv = argv;
3191
3192 /*
3193 * Set default pool features.
3194 */
3195 pool_features_init(&pf);
3196
3197 dm_consume_args(&as, 4);
3198 r = parse_pool_features(&as, &pf, ti);
3199 if (r)
3200 goto out_unlock;
3201
3202 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
3203 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3204 if (r) {
3205 ti->error = "Error opening metadata block device";
3206 goto out_unlock;
3207 }
3208 warn_if_metadata_device_too_big(metadata_dev->bdev);
3209
3210 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
3211 if (r) {
3212 ti->error = "Error getting data device";
3213 goto out_metadata;
3214 }
3215
3216 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3217 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3218 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3219 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3220 ti->error = "Invalid block size";
3221 r = -EINVAL;
3222 goto out;
3223 }
3224
3225 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3226 ti->error = "Invalid low water mark";
3227 r = -EINVAL;
3228 goto out;
3229 }
3230
3231 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3232 if (!pt) {
3233 r = -ENOMEM;
3234 goto out;
3235 }
3236
3237 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
3238 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3239 if (IS_ERR(pool)) {
3240 r = PTR_ERR(pool);
3241 goto out_free_pt;
3242 }
3243
3244 /*
3245 * 'pool_created' reflects whether this is the first table load.
3246 * Top level discard support is not allowed to be changed after
3247 * initial load. This would require a pool reload to trigger thin
3248 * device changes.
3249 */
3250 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3251 ti->error = "Discard support cannot be disabled once enabled";
3252 r = -EINVAL;
3253 goto out_flags_changed;
3254 }
3255
3256 pt->pool = pool;
3257 pt->ti = ti;
3258 pt->metadata_dev = metadata_dev;
3259 pt->data_dev = data_dev;
3260 pt->low_water_blocks = low_water_blocks;
3261 pt->adjusted_pf = pt->requested_pf = pf;
3262 ti->num_flush_bios = 1;
3263
3264 /*
3265 * Only need to enable discards if the pool should pass
3266 * them down to the data device. The thin device's discard
3267 * processing will cause mappings to be removed from the btree.
3268 */
3269 ti->discard_zeroes_data_unsupported = true;
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->bi_bdev = 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{
3710 int r = -EINVAL;
3711 struct pool_c *pt = ti->private;
3712 struct pool *pool = pt->pool;
3713
3714 if (get_pool_mode(pool) >= PM_READ_ONLY) {
3715 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3716 dm_device_name(pool->pool_md));
3717 return -EOPNOTSUPP;
3718 }
3719
3720 if (!strcasecmp(argv[0], "create_thin"))
3721 r = process_create_thin_mesg(argc, argv, pool);
3722
3723 else if (!strcasecmp(argv[0], "create_snap"))
3724 r = process_create_snap_mesg(argc, argv, pool);
3725
3726 else if (!strcasecmp(argv[0], "delete"))
3727 r = process_delete_mesg(argc, argv, pool);
3728
3729 else if (!strcasecmp(argv[0], "set_transaction_id"))
3730 r = process_set_transaction_id_mesg(argc, argv, pool);
3731
3732 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3733 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3734
3735 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3736 r = process_release_metadata_snap_mesg(argc, argv, pool);
3737
3738 else
3739 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3740
3741 if (!r)
3742 (void) commit(pool);
3743
3744 return r;
3745}
3746
3747static void emit_flags(struct pool_features *pf, char *result,
3748 unsigned sz, unsigned maxlen)
3749{
3750 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
3751 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3752 pf->error_if_no_space;
3753 DMEMIT("%u ", count);
3754
3755 if (!pf->zero_new_blocks)
3756 DMEMIT("skip_block_zeroing ");
3757
3758 if (!pf->discard_enabled)
3759 DMEMIT("ignore_discard ");
3760
3761 if (!pf->discard_passdown)
3762 DMEMIT("no_discard_passdown ");
3763
3764 if (pf->mode == PM_READ_ONLY)
3765 DMEMIT("read_only ");
3766
3767 if (pf->error_if_no_space)
3768 DMEMIT("error_if_no_space ");
3769}
3770
3771/*
3772 * Status line is:
3773 * <transaction id> <used metadata sectors>/<total metadata sectors>
3774 * <used data sectors>/<total data sectors> <held metadata root>
3775 * <pool mode> <discard config> <no space config> <needs_check>
3776 */
3777static void pool_status(struct dm_target *ti, status_type_t type,
3778 unsigned status_flags, char *result, unsigned maxlen)
3779{
3780 int r;
3781 unsigned sz = 0;
3782 uint64_t transaction_id;
3783 dm_block_t nr_free_blocks_data;
3784 dm_block_t nr_free_blocks_metadata;
3785 dm_block_t nr_blocks_data;
3786 dm_block_t nr_blocks_metadata;
3787 dm_block_t held_root;
3788 char buf[BDEVNAME_SIZE];
3789 char buf2[BDEVNAME_SIZE];
3790 struct pool_c *pt = ti->private;
3791 struct pool *pool = pt->pool;
3792
3793 switch (type) {
3794 case STATUSTYPE_INFO:
3795 if (get_pool_mode(pool) == PM_FAIL) {
3796 DMEMIT("Fail");
3797 break;
3798 }
3799
3800 /* Commit to ensure statistics aren't out-of-date */
3801 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3802 (void) commit(pool);
3803
3804 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3805 if (r) {
3806 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3807 dm_device_name(pool->pool_md), r);
3808 goto err;
3809 }
3810
3811 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3812 if (r) {
3813 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3814 dm_device_name(pool->pool_md), r);
3815 goto err;
3816 }
3817
3818 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3819 if (r) {
3820 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3821 dm_device_name(pool->pool_md), r);
3822 goto err;
3823 }
3824
3825 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3826 if (r) {
3827 DMERR("%s: dm_pool_get_free_block_count returned %d",
3828 dm_device_name(pool->pool_md), r);
3829 goto err;
3830 }
3831
3832 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3833 if (r) {
3834 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3835 dm_device_name(pool->pool_md), r);
3836 goto err;
3837 }
3838
3839 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3840 if (r) {
3841 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3842 dm_device_name(pool->pool_md), r);
3843 goto err;
3844 }
3845
3846 DMEMIT("%llu %llu/%llu %llu/%llu ",
3847 (unsigned long long)transaction_id,
3848 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3849 (unsigned long long)nr_blocks_metadata,
3850 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3851 (unsigned long long)nr_blocks_data);
3852
3853 if (held_root)
3854 DMEMIT("%llu ", held_root);
3855 else
3856 DMEMIT("- ");
3857
3858 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
3859 DMEMIT("out_of_data_space ");
3860 else if (pool->pf.mode == PM_READ_ONLY)
3861 DMEMIT("ro ");
3862 else
3863 DMEMIT("rw ");
3864
3865 if (!pool->pf.discard_enabled)
3866 DMEMIT("ignore_discard ");
3867 else if (pool->pf.discard_passdown)
3868 DMEMIT("discard_passdown ");
3869 else
3870 DMEMIT("no_discard_passdown ");
3871
3872 if (pool->pf.error_if_no_space)
3873 DMEMIT("error_if_no_space ");
3874 else
3875 DMEMIT("queue_if_no_space ");
3876
3877 if (dm_pool_metadata_needs_check(pool->pmd))
3878 DMEMIT("needs_check ");
3879 else
3880 DMEMIT("- ");
3881
3882 break;
3883
3884 case STATUSTYPE_TABLE:
3885 DMEMIT("%s %s %lu %llu ",
3886 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
3887 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
3888 (unsigned long)pool->sectors_per_block,
3889 (unsigned long long)pt->low_water_blocks);
3890 emit_flags(&pt->requested_pf, result, sz, maxlen);
3891 break;
3892 }
3893 return;
3894
3895err:
3896 DMEMIT("Error");
3897}
3898
3899static int pool_iterate_devices(struct dm_target *ti,
3900 iterate_devices_callout_fn fn, void *data)
3901{
3902 struct pool_c *pt = ti->private;
3903
3904 return fn(ti, pt->data_dev, 0, ti->len, data);
3905}
3906
3907static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
3908{
3909 struct pool_c *pt = ti->private;
3910 struct pool *pool = pt->pool;
3911 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3912
3913 /*
3914 * If max_sectors is smaller than pool->sectors_per_block adjust it
3915 * to the highest possible power-of-2 factor of pool->sectors_per_block.
3916 * This is especially beneficial when the pool's data device is a RAID
3917 * device that has a full stripe width that matches pool->sectors_per_block
3918 * -- because even though partial RAID stripe-sized IOs will be issued to a
3919 * single RAID stripe; when aggregated they will end on a full RAID stripe
3920 * boundary.. which avoids additional partial RAID stripe writes cascading
3921 */
3922 if (limits->max_sectors < pool->sectors_per_block) {
3923 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
3924 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
3925 limits->max_sectors--;
3926 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
3927 }
3928 }
3929
3930 /*
3931 * If the system-determined stacked limits are compatible with the
3932 * pool's blocksize (io_opt is a factor) do not override them.
3933 */
3934 if (io_opt_sectors < pool->sectors_per_block ||
3935 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
3936 if (is_factor(pool->sectors_per_block, limits->max_sectors))
3937 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
3938 else
3939 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
3940 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
3941 }
3942
3943 /*
3944 * pt->adjusted_pf is a staging area for the actual features to use.
3945 * They get transferred to the live pool in bind_control_target()
3946 * called from pool_preresume().
3947 */
3948 if (!pt->adjusted_pf.discard_enabled) {
3949 /*
3950 * Must explicitly disallow stacking discard limits otherwise the
3951 * block layer will stack them if pool's data device has support.
3952 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
3953 * user to see that, so make sure to set all discard limits to 0.
3954 */
3955 limits->discard_granularity = 0;
3956 return;
3957 }
3958
3959 disable_passdown_if_not_supported(pt);
3960
3961 /*
3962 * The pool uses the same discard limits as the underlying data
3963 * device. DM core has already set this up.
3964 */
3965}
3966
3967static struct target_type pool_target = {
3968 .name = "thin-pool",
3969 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
3970 DM_TARGET_IMMUTABLE,
3971 .version = {1, 19, 0},
3972 .module = THIS_MODULE,
3973 .ctr = pool_ctr,
3974 .dtr = pool_dtr,
3975 .map = pool_map,
3976 .presuspend = pool_presuspend,
3977 .presuspend_undo = pool_presuspend_undo,
3978 .postsuspend = pool_postsuspend,
3979 .preresume = pool_preresume,
3980 .resume = pool_resume,
3981 .message = pool_message,
3982 .status = pool_status,
3983 .iterate_devices = pool_iterate_devices,
3984 .io_hints = pool_io_hints,
3985};
3986
3987/*----------------------------------------------------------------
3988 * Thin target methods
3989 *--------------------------------------------------------------*/
3990static void thin_get(struct thin_c *tc)
3991{
3992 atomic_inc(&tc->refcount);
3993}
3994
3995static void thin_put(struct thin_c *tc)
3996{
3997 if (atomic_dec_and_test(&tc->refcount))
3998 complete(&tc->can_destroy);
3999}
4000
4001static void thin_dtr(struct dm_target *ti)
4002{
4003 struct thin_c *tc = ti->private;
4004 unsigned long flags;
4005
4006 spin_lock_irqsave(&tc->pool->lock, flags);
4007 list_del_rcu(&tc->list);
4008 spin_unlock_irqrestore(&tc->pool->lock, flags);
4009 synchronize_rcu();
4010
4011 thin_put(tc);
4012 wait_for_completion(&tc->can_destroy);
4013
4014 mutex_lock(&dm_thin_pool_table.mutex);
4015
4016 __pool_dec(tc->pool);
4017 dm_pool_close_thin_device(tc->td);
4018 dm_put_device(ti, tc->pool_dev);
4019 if (tc->origin_dev)
4020 dm_put_device(ti, tc->origin_dev);
4021 kfree(tc);
4022
4023 mutex_unlock(&dm_thin_pool_table.mutex);
4024}
4025
4026/*
4027 * Thin target parameters:
4028 *
4029 * <pool_dev> <dev_id> [origin_dev]
4030 *
4031 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4032 * dev_id: the internal device identifier
4033 * origin_dev: a device external to the pool that should act as the origin
4034 *
4035 * If the pool device has discards disabled, they get disabled for the thin
4036 * device as well.
4037 */
4038static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
4039{
4040 int r;
4041 struct thin_c *tc;
4042 struct dm_dev *pool_dev, *origin_dev;
4043 struct mapped_device *pool_md;
4044 unsigned long flags;
4045
4046 mutex_lock(&dm_thin_pool_table.mutex);
4047
4048 if (argc != 2 && argc != 3) {
4049 ti->error = "Invalid argument count";
4050 r = -EINVAL;
4051 goto out_unlock;
4052 }
4053
4054 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4055 if (!tc) {
4056 ti->error = "Out of memory";
4057 r = -ENOMEM;
4058 goto out_unlock;
4059 }
4060 tc->thin_md = dm_table_get_md(ti->table);
4061 spin_lock_init(&tc->lock);
4062 INIT_LIST_HEAD(&tc->deferred_cells);
4063 bio_list_init(&tc->deferred_bio_list);
4064 bio_list_init(&tc->retry_on_resume_list);
4065 tc->sort_bio_list = RB_ROOT;
4066
4067 if (argc == 3) {
4068 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
4069 if (r) {
4070 ti->error = "Error opening origin device";
4071 goto bad_origin_dev;
4072 }
4073 tc->origin_dev = origin_dev;
4074 }
4075
4076 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4077 if (r) {
4078 ti->error = "Error opening pool device";
4079 goto bad_pool_dev;
4080 }
4081 tc->pool_dev = pool_dev;
4082
4083 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4084 ti->error = "Invalid device id";
4085 r = -EINVAL;
4086 goto bad_common;
4087 }
4088
4089 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4090 if (!pool_md) {
4091 ti->error = "Couldn't get pool mapped device";
4092 r = -EINVAL;
4093 goto bad_common;
4094 }
4095
4096 tc->pool = __pool_table_lookup(pool_md);
4097 if (!tc->pool) {
4098 ti->error = "Couldn't find pool object";
4099 r = -EINVAL;
4100 goto bad_pool_lookup;
4101 }
4102 __pool_inc(tc->pool);
4103
4104 if (get_pool_mode(tc->pool) == PM_FAIL) {
4105 ti->error = "Couldn't open thin device, Pool is in fail mode";
4106 r = -EINVAL;
4107 goto bad_pool;
4108 }
4109
4110 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4111 if (r) {
4112 ti->error = "Couldn't open thin internal device";
4113 goto bad_pool;
4114 }
4115
4116 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4117 if (r)
4118 goto bad;
4119
4120 ti->num_flush_bios = 1;
4121 ti->flush_supported = true;
4122 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4123
4124 /* In case the pool supports discards, pass them on. */
4125 ti->discard_zeroes_data_unsupported = true;
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, int err)
4185{
4186 unsigned long flags;
4187 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4188 struct list_head work;
4189 struct dm_thin_new_mapping *m, *tmp;
4190 struct pool *pool = h->tc->pool;
4191
4192 if (h->shared_read_entry) {
4193 INIT_LIST_HEAD(&work);
4194 dm_deferred_entry_dec(h->shared_read_entry, &work);
4195
4196 spin_lock_irqsave(&pool->lock, flags);
4197 list_for_each_entry_safe(m, tmp, &work, list) {
4198 list_del(&m->list);
4199 __complete_mapping_preparation(m);
4200 }
4201 spin_unlock_irqrestore(&pool->lock, flags);
4202 }
4203
4204 if (h->all_io_entry) {
4205 INIT_LIST_HEAD(&work);
4206 dm_deferred_entry_dec(h->all_io_entry, &work);
4207 if (!list_empty(&work)) {
4208 spin_lock_irqsave(&pool->lock, flags);
4209 list_for_each_entry_safe(m, tmp, &work, list)
4210 list_add_tail(&m->list, &pool->prepared_discards);
4211 spin_unlock_irqrestore(&pool->lock, flags);
4212 wake_worker(pool);
4213 }
4214 }
4215
4216 if (h->cell)
4217 cell_defer_no_holder(h->tc, h->cell);
4218
4219 return 0;
4220}
4221
4222static void thin_presuspend(struct dm_target *ti)
4223{
4224 struct thin_c *tc = ti->private;
4225
4226 if (dm_noflush_suspending(ti))
4227 noflush_work(tc, do_noflush_start);
4228}
4229
4230static void thin_postsuspend(struct dm_target *ti)
4231{
4232 struct thin_c *tc = ti->private;
4233
4234 /*
4235 * The dm_noflush_suspending flag has been cleared by now, so
4236 * unfortunately we must always run this.
4237 */
4238 noflush_work(tc, do_noflush_stop);
4239}
4240
4241static int thin_preresume(struct dm_target *ti)
4242{
4243 struct thin_c *tc = ti->private;
4244
4245 if (tc->origin_dev)
4246 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4247
4248 return 0;
4249}
4250
4251/*
4252 * <nr mapped sectors> <highest mapped sector>
4253 */
4254static void thin_status(struct dm_target *ti, status_type_t type,
4255 unsigned status_flags, char *result, unsigned maxlen)
4256{
4257 int r;
4258 ssize_t sz = 0;
4259 dm_block_t mapped, highest;
4260 char buf[BDEVNAME_SIZE];
4261 struct thin_c *tc = ti->private;
4262
4263 if (get_pool_mode(tc->pool) == PM_FAIL) {
4264 DMEMIT("Fail");
4265 return;
4266 }
4267
4268 if (!tc->td)
4269 DMEMIT("-");
4270 else {
4271 switch (type) {
4272 case STATUSTYPE_INFO:
4273 r = dm_thin_get_mapped_count(tc->td, &mapped);
4274 if (r) {
4275 DMERR("dm_thin_get_mapped_count returned %d", r);
4276 goto err;
4277 }
4278
4279 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4280 if (r < 0) {
4281 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4282 goto err;
4283 }
4284
4285 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4286 if (r)
4287 DMEMIT("%llu", ((highest + 1) *
4288 tc->pool->sectors_per_block) - 1);
4289 else
4290 DMEMIT("-");
4291 break;
4292
4293 case STATUSTYPE_TABLE:
4294 DMEMIT("%s %lu",
4295 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4296 (unsigned long) tc->dev_id);
4297 if (tc->origin_dev)
4298 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4299 break;
4300 }
4301 }
4302
4303 return;
4304
4305err:
4306 DMEMIT("Error");
4307}
4308
4309static int thin_iterate_devices(struct dm_target *ti,
4310 iterate_devices_callout_fn fn, void *data)
4311{
4312 sector_t blocks;
4313 struct thin_c *tc = ti->private;
4314 struct pool *pool = tc->pool;
4315
4316 /*
4317 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4318 * we follow a more convoluted path through to the pool's target.
4319 */
4320 if (!pool->ti)
4321 return 0; /* nothing is bound */
4322
4323 blocks = pool->ti->len;
4324 (void) sector_div(blocks, pool->sectors_per_block);
4325 if (blocks)
4326 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4327
4328 return 0;
4329}
4330
4331static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4332{
4333 struct thin_c *tc = ti->private;
4334 struct pool *pool = tc->pool;
4335
4336 if (!pool->pf.discard_enabled)
4337 return;
4338
4339 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4340 limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */
4341}
4342
4343static struct target_type thin_target = {
4344 .name = "thin",
4345 .version = {1, 19, 0},
4346 .module = THIS_MODULE,
4347 .ctr = thin_ctr,
4348 .dtr = thin_dtr,
4349 .map = thin_map,
4350 .end_io = thin_endio,
4351 .preresume = thin_preresume,
4352 .presuspend = thin_presuspend,
4353 .postsuspend = thin_postsuspend,
4354 .status = thin_status,
4355 .iterate_devices = thin_iterate_devices,
4356 .io_hints = thin_io_hints,
4357};
4358
4359/*----------------------------------------------------------------*/
4360
4361static int __init dm_thin_init(void)
4362{
4363 int r;
4364
4365 pool_table_init();
4366
4367 r = dm_register_target(&thin_target);
4368 if (r)
4369 return r;
4370
4371 r = dm_register_target(&pool_target);
4372 if (r)
4373 goto bad_pool_target;
4374
4375 r = -ENOMEM;
4376
4377 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4378 if (!_new_mapping_cache)
4379 goto bad_new_mapping_cache;
4380
4381 return 0;
4382
4383bad_new_mapping_cache:
4384 dm_unregister_target(&pool_target);
4385bad_pool_target:
4386 dm_unregister_target(&thin_target);
4387
4388 return r;
4389}
4390
4391static void dm_thin_exit(void)
4392{
4393 dm_unregister_target(&thin_target);
4394 dm_unregister_target(&pool_target);
4395
4396 kmem_cache_destroy(_new_mapping_cache);
4397}
4398
4399module_init(dm_thin_init);
4400module_exit(dm_thin_exit);
4401
4402module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
4403MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4404
4405MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4406MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
4407MODULE_LICENSE("GPL");