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