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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011-2012 Red Hat UK.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-thin-metadata.h"
9#include "dm-bio-prison-v1.h"
10#include "dm.h"
11
12#include <linux/device-mapper.h>
13#include <linux/dm-io.h>
14#include <linux/dm-kcopyd.h>
15#include <linux/jiffies.h>
16#include <linux/log2.h>
17#include <linux/list.h>
18#include <linux/rculist.h>
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/slab.h>
22#include <linux/vmalloc.h>
23#include <linux/sort.h>
24#include <linux/rbtree.h>
25
26#define DM_MSG_PREFIX "thin"
27
28/*
29 * Tunable constants
30 */
31#define ENDIO_HOOK_POOL_SIZE 1024
32#define MAPPING_POOL_SIZE 1024
33#define COMMIT_PERIOD HZ
34#define NO_SPACE_TIMEOUT_SECS 60
35
36static unsigned int no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
37
38DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
39 "A percentage of time allocated for copy on write");
40
41/*
42 * The block size of the device holding pool data must be
43 * between 64KB and 1GB.
44 */
45#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
46#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
47
48/*
49 * Device id is restricted to 24 bits.
50 */
51#define MAX_DEV_ID ((1 << 24) - 1)
52
53/*
54 * How do we handle breaking sharing of data blocks?
55 * =================================================
56 *
57 * We use a standard copy-on-write btree to store the mappings for the
58 * devices (note I'm talking about copy-on-write of the metadata here, not
59 * the data). When you take an internal snapshot you clone the root node
60 * of the origin btree. After this there is no concept of an origin or a
61 * snapshot. They are just two device trees that happen to point to the
62 * same data blocks.
63 *
64 * When we get a write in we decide if it's to a shared data block using
65 * some timestamp magic. If it is, we have to break sharing.
66 *
67 * Let's say we write to a shared block in what was the origin. The
68 * steps are:
69 *
70 * i) plug io further to this physical block. (see bio_prison code).
71 *
72 * ii) quiesce any read io to that shared data block. Obviously
73 * including all devices that share this block. (see dm_deferred_set code)
74 *
75 * iii) copy the data block to a newly allocate block. This step can be
76 * missed out if the io covers the block. (schedule_copy).
77 *
78 * iv) insert the new mapping into the origin's btree
79 * (process_prepared_mapping). This act of inserting breaks some
80 * sharing of btree nodes between the two devices. Breaking sharing only
81 * effects the btree of that specific device. Btrees for the other
82 * devices that share the block never change. The btree for the origin
83 * device as it was after the last commit is untouched, ie. we're using
84 * persistent data structures in the functional programming sense.
85 *
86 * v) unplug io to this physical block, including the io that triggered
87 * the breaking of sharing.
88 *
89 * Steps (ii) and (iii) occur in parallel.
90 *
91 * The metadata _doesn't_ need to be committed before the io continues. We
92 * get away with this because the io is always written to a _new_ block.
93 * If there's a crash, then:
94 *
95 * - The origin mapping will point to the old origin block (the shared
96 * one). This will contain the data as it was before the io that triggered
97 * the breaking of sharing came in.
98 *
99 * - The snap mapping still points to the old block. As it would after
100 * the commit.
101 *
102 * The downside of this scheme is the timestamp magic isn't perfect, and
103 * will continue to think that data block in the snapshot device is shared
104 * even after the write to the origin has broken sharing. I suspect data
105 * blocks will typically be shared by many different devices, so we're
106 * breaking sharing n + 1 times, rather than n, where n is the number of
107 * devices that reference this data block. At the moment I think the
108 * benefits far, far outweigh the disadvantages.
109 */
110
111/*----------------------------------------------------------------*/
112
113/*
114 * Key building.
115 */
116enum lock_space {
117 VIRTUAL,
118 PHYSICAL
119};
120
121static bool build_key(struct dm_thin_device *td, enum lock_space ls,
122 dm_block_t b, dm_block_t e, struct dm_cell_key *key)
123{
124 key->virtual = (ls == VIRTUAL);
125 key->dev = dm_thin_dev_id(td);
126 key->block_begin = b;
127 key->block_end = e;
128
129 return dm_cell_key_has_valid_range(key);
130}
131
132static void build_data_key(struct dm_thin_device *td, dm_block_t b,
133 struct dm_cell_key *key)
134{
135 (void) build_key(td, PHYSICAL, b, b + 1llu, key);
136}
137
138static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
139 struct dm_cell_key *key)
140{
141 (void) build_key(td, VIRTUAL, b, b + 1llu, key);
142}
143
144/*----------------------------------------------------------------*/
145
146#define THROTTLE_THRESHOLD (1 * HZ)
147
148struct throttle {
149 struct rw_semaphore lock;
150 unsigned long threshold;
151 bool throttle_applied;
152};
153
154static void throttle_init(struct throttle *t)
155{
156 init_rwsem(&t->lock);
157 t->throttle_applied = false;
158}
159
160static void throttle_work_start(struct throttle *t)
161{
162 t->threshold = jiffies + THROTTLE_THRESHOLD;
163}
164
165static void throttle_work_update(struct throttle *t)
166{
167 if (!t->throttle_applied && time_is_before_jiffies(t->threshold)) {
168 down_write(&t->lock);
169 t->throttle_applied = true;
170 }
171}
172
173static void throttle_work_complete(struct throttle *t)
174{
175 if (t->throttle_applied) {
176 t->throttle_applied = false;
177 up_write(&t->lock);
178 }
179}
180
181static void throttle_lock(struct throttle *t)
182{
183 down_read(&t->lock);
184}
185
186static void throttle_unlock(struct throttle *t)
187{
188 up_read(&t->lock);
189}
190
191/*----------------------------------------------------------------*/
192
193/*
194 * A pool device ties together a metadata device and a data device. It
195 * also provides the interface for creating and destroying internal
196 * devices.
197 */
198struct dm_thin_new_mapping;
199
200/*
201 * The pool runs in various modes. Ordered in degraded order for comparisons.
202 */
203enum pool_mode {
204 PM_WRITE, /* metadata may be changed */
205 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
206
207 /*
208 * Like READ_ONLY, except may switch back to WRITE on metadata resize. Reported as READ_ONLY.
209 */
210 PM_OUT_OF_METADATA_SPACE,
211 PM_READ_ONLY, /* metadata may not be changed */
212
213 PM_FAIL, /* all I/O fails */
214};
215
216struct pool_features {
217 enum pool_mode mode;
218
219 bool zero_new_blocks:1;
220 bool discard_enabled:1;
221 bool discard_passdown:1;
222 bool error_if_no_space:1;
223};
224
225struct thin_c;
226typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
227typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
228typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
229
230#define CELL_SORT_ARRAY_SIZE 8192
231
232struct pool {
233 struct list_head list;
234 struct dm_target *ti; /* Only set if a pool target is bound */
235
236 struct mapped_device *pool_md;
237 struct block_device *data_dev;
238 struct block_device *md_dev;
239 struct dm_pool_metadata *pmd;
240
241 dm_block_t low_water_blocks;
242 uint32_t sectors_per_block;
243 int sectors_per_block_shift;
244
245 struct pool_features pf;
246 bool low_water_triggered:1; /* A dm event has been sent */
247 bool suspended:1;
248 bool out_of_data_space:1;
249
250 struct dm_bio_prison *prison;
251 struct dm_kcopyd_client *copier;
252
253 struct work_struct worker;
254 struct workqueue_struct *wq;
255 struct throttle throttle;
256 struct delayed_work waker;
257 struct delayed_work no_space_timeout;
258
259 unsigned long last_commit_jiffies;
260 unsigned int ref_count;
261
262 spinlock_t lock;
263 struct bio_list deferred_flush_bios;
264 struct bio_list deferred_flush_completions;
265 struct list_head prepared_mappings;
266 struct list_head prepared_discards;
267 struct list_head prepared_discards_pt2;
268 struct list_head active_thins;
269
270 struct dm_deferred_set *shared_read_ds;
271 struct dm_deferred_set *all_io_ds;
272
273 struct dm_thin_new_mapping *next_mapping;
274
275 process_bio_fn process_bio;
276 process_bio_fn process_discard;
277
278 process_cell_fn process_cell;
279 process_cell_fn process_discard_cell;
280
281 process_mapping_fn process_prepared_mapping;
282 process_mapping_fn process_prepared_discard;
283 process_mapping_fn process_prepared_discard_pt2;
284
285 struct dm_bio_prison_cell **cell_sort_array;
286
287 mempool_t mapping_pool;
288};
289
290static void metadata_operation_failed(struct pool *pool, const char *op, int r);
291
292static enum pool_mode get_pool_mode(struct pool *pool)
293{
294 return pool->pf.mode;
295}
296
297static void notify_of_pool_mode_change(struct pool *pool)
298{
299 static const char *descs[] = {
300 "write",
301 "out-of-data-space",
302 "read-only",
303 "read-only",
304 "fail"
305 };
306 const char *extra_desc = NULL;
307 enum pool_mode mode = get_pool_mode(pool);
308
309 if (mode == PM_OUT_OF_DATA_SPACE) {
310 if (!pool->pf.error_if_no_space)
311 extra_desc = " (queue IO)";
312 else
313 extra_desc = " (error IO)";
314 }
315
316 dm_table_event(pool->ti->table);
317 DMINFO("%s: switching pool to %s%s mode",
318 dm_device_name(pool->pool_md),
319 descs[(int)mode], extra_desc ? : "");
320}
321
322/*
323 * Target context for a pool.
324 */
325struct pool_c {
326 struct dm_target *ti;
327 struct pool *pool;
328 struct dm_dev *data_dev;
329 struct dm_dev *metadata_dev;
330
331 dm_block_t low_water_blocks;
332 struct pool_features requested_pf; /* Features requested during table load */
333 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
334};
335
336/*
337 * Target context for a thin.
338 */
339struct thin_c {
340 struct list_head list;
341 struct dm_dev *pool_dev;
342 struct dm_dev *origin_dev;
343 sector_t origin_size;
344 dm_thin_id dev_id;
345
346 struct pool *pool;
347 struct dm_thin_device *td;
348 struct mapped_device *thin_md;
349
350 bool requeue_mode:1;
351 spinlock_t lock;
352 struct list_head deferred_cells;
353 struct bio_list deferred_bio_list;
354 struct bio_list retry_on_resume_list;
355 struct rb_root sort_bio_list; /* sorted list of deferred bios */
356
357 /*
358 * Ensures the thin is not destroyed until the worker has finished
359 * iterating the active_thins list.
360 */
361 refcount_t refcount;
362 struct completion can_destroy;
363};
364
365/*----------------------------------------------------------------*/
366
367static bool block_size_is_power_of_two(struct pool *pool)
368{
369 return pool->sectors_per_block_shift >= 0;
370}
371
372static sector_t block_to_sectors(struct pool *pool, dm_block_t b)
373{
374 return block_size_is_power_of_two(pool) ?
375 (b << pool->sectors_per_block_shift) :
376 (b * pool->sectors_per_block);
377}
378
379/*----------------------------------------------------------------*/
380
381struct discard_op {
382 struct thin_c *tc;
383 struct blk_plug plug;
384 struct bio *parent_bio;
385 struct bio *bio;
386};
387
388static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent)
389{
390 BUG_ON(!parent);
391
392 op->tc = tc;
393 blk_start_plug(&op->plug);
394 op->parent_bio = parent;
395 op->bio = NULL;
396}
397
398static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e)
399{
400 struct thin_c *tc = op->tc;
401 sector_t s = block_to_sectors(tc->pool, data_b);
402 sector_t len = block_to_sectors(tc->pool, data_e - data_b);
403
404 return __blkdev_issue_discard(tc->pool_dev->bdev, s, len, GFP_NOIO, &op->bio);
405}
406
407static void end_discard(struct discard_op *op, int r)
408{
409 if (op->bio) {
410 /*
411 * Even if one of the calls to issue_discard failed, we
412 * need to wait for the chain to complete.
413 */
414 bio_chain(op->bio, op->parent_bio);
415 op->bio->bi_opf = REQ_OP_DISCARD;
416 submit_bio(op->bio);
417 }
418
419 blk_finish_plug(&op->plug);
420
421 /*
422 * Even if r is set, there could be sub discards in flight that we
423 * need to wait for.
424 */
425 if (r && !op->parent_bio->bi_status)
426 op->parent_bio->bi_status = errno_to_blk_status(r);
427 bio_endio(op->parent_bio);
428}
429
430/*----------------------------------------------------------------*/
431
432/*
433 * wake_worker() is used when new work is queued and when pool_resume is
434 * ready to continue deferred IO processing.
435 */
436static void wake_worker(struct pool *pool)
437{
438 queue_work(pool->wq, &pool->worker);
439}
440
441/*----------------------------------------------------------------*/
442
443static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
444 struct dm_bio_prison_cell **cell_result)
445{
446 int r;
447 struct dm_bio_prison_cell *cell_prealloc;
448
449 /*
450 * Allocate a cell from the prison's mempool.
451 * This might block but it can't fail.
452 */
453 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
454
455 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
456 if (r)
457 /*
458 * We reused an old cell; we can get rid of
459 * the new one.
460 */
461 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
462
463 return r;
464}
465
466static void cell_release(struct pool *pool,
467 struct dm_bio_prison_cell *cell,
468 struct bio_list *bios)
469{
470 dm_cell_release(pool->prison, cell, bios);
471 dm_bio_prison_free_cell(pool->prison, cell);
472}
473
474static void cell_visit_release(struct pool *pool,
475 void (*fn)(void *, struct dm_bio_prison_cell *),
476 void *context,
477 struct dm_bio_prison_cell *cell)
478{
479 dm_cell_visit_release(pool->prison, fn, context, cell);
480 dm_bio_prison_free_cell(pool->prison, cell);
481}
482
483static void cell_release_no_holder(struct pool *pool,
484 struct dm_bio_prison_cell *cell,
485 struct bio_list *bios)
486{
487 dm_cell_release_no_holder(pool->prison, cell, bios);
488 dm_bio_prison_free_cell(pool->prison, cell);
489}
490
491static void cell_error_with_code(struct pool *pool,
492 struct dm_bio_prison_cell *cell, blk_status_t error_code)
493{
494 dm_cell_error(pool->prison, cell, error_code);
495 dm_bio_prison_free_cell(pool->prison, cell);
496}
497
498static blk_status_t get_pool_io_error_code(struct pool *pool)
499{
500 return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR;
501}
502
503static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
504{
505 cell_error_with_code(pool, cell, get_pool_io_error_code(pool));
506}
507
508static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
509{
510 cell_error_with_code(pool, cell, 0);
511}
512
513static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
514{
515 cell_error_with_code(pool, cell, BLK_STS_DM_REQUEUE);
516}
517
518/*----------------------------------------------------------------*/
519
520/*
521 * A global list of pools that uses a struct mapped_device as a key.
522 */
523static struct dm_thin_pool_table {
524 struct mutex mutex;
525 struct list_head pools;
526} dm_thin_pool_table;
527
528static void pool_table_init(void)
529{
530 mutex_init(&dm_thin_pool_table.mutex);
531 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
532}
533
534static void pool_table_exit(void)
535{
536 mutex_destroy(&dm_thin_pool_table.mutex);
537}
538
539static void __pool_table_insert(struct pool *pool)
540{
541 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
542 list_add(&pool->list, &dm_thin_pool_table.pools);
543}
544
545static void __pool_table_remove(struct pool *pool)
546{
547 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
548 list_del(&pool->list);
549}
550
551static struct pool *__pool_table_lookup(struct mapped_device *md)
552{
553 struct pool *pool = NULL, *tmp;
554
555 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
556
557 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
558 if (tmp->pool_md == md) {
559 pool = tmp;
560 break;
561 }
562 }
563
564 return pool;
565}
566
567static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
568{
569 struct pool *pool = NULL, *tmp;
570
571 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
572
573 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
574 if (tmp->md_dev == md_dev) {
575 pool = tmp;
576 break;
577 }
578 }
579
580 return pool;
581}
582
583/*----------------------------------------------------------------*/
584
585struct dm_thin_endio_hook {
586 struct thin_c *tc;
587 struct dm_deferred_entry *shared_read_entry;
588 struct dm_deferred_entry *all_io_entry;
589 struct dm_thin_new_mapping *overwrite_mapping;
590 struct rb_node rb_node;
591 struct dm_bio_prison_cell *cell;
592};
593
594static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
595{
596 bio_list_merge(bios, master);
597 bio_list_init(master);
598}
599
600static void error_bio_list(struct bio_list *bios, blk_status_t error)
601{
602 struct bio *bio;
603
604 while ((bio = bio_list_pop(bios))) {
605 bio->bi_status = error;
606 bio_endio(bio);
607 }
608}
609
610static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master,
611 blk_status_t error)
612{
613 struct bio_list bios;
614
615 bio_list_init(&bios);
616
617 spin_lock_irq(&tc->lock);
618 __merge_bio_list(&bios, master);
619 spin_unlock_irq(&tc->lock);
620
621 error_bio_list(&bios, error);
622}
623
624static void requeue_deferred_cells(struct thin_c *tc)
625{
626 struct pool *pool = tc->pool;
627 struct list_head cells;
628 struct dm_bio_prison_cell *cell, *tmp;
629
630 INIT_LIST_HEAD(&cells);
631
632 spin_lock_irq(&tc->lock);
633 list_splice_init(&tc->deferred_cells, &cells);
634 spin_unlock_irq(&tc->lock);
635
636 list_for_each_entry_safe(cell, tmp, &cells, user_list)
637 cell_requeue(pool, cell);
638}
639
640static void requeue_io(struct thin_c *tc)
641{
642 struct bio_list bios;
643
644 bio_list_init(&bios);
645
646 spin_lock_irq(&tc->lock);
647 __merge_bio_list(&bios, &tc->deferred_bio_list);
648 __merge_bio_list(&bios, &tc->retry_on_resume_list);
649 spin_unlock_irq(&tc->lock);
650
651 error_bio_list(&bios, BLK_STS_DM_REQUEUE);
652 requeue_deferred_cells(tc);
653}
654
655static void error_retry_list_with_code(struct pool *pool, blk_status_t error)
656{
657 struct thin_c *tc;
658
659 rcu_read_lock();
660 list_for_each_entry_rcu(tc, &pool->active_thins, list)
661 error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
662 rcu_read_unlock();
663}
664
665static void error_retry_list(struct pool *pool)
666{
667 error_retry_list_with_code(pool, get_pool_io_error_code(pool));
668}
669
670/*
671 * This section of code contains the logic for processing a thin device's IO.
672 * Much of the code depends on pool object resources (lists, workqueues, etc)
673 * but most is exclusively called from the thin target rather than the thin-pool
674 * target.
675 */
676
677static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
678{
679 struct pool *pool = tc->pool;
680 sector_t block_nr = bio->bi_iter.bi_sector;
681
682 if (block_size_is_power_of_two(pool))
683 block_nr >>= pool->sectors_per_block_shift;
684 else
685 (void) sector_div(block_nr, pool->sectors_per_block);
686
687 return block_nr;
688}
689
690/*
691 * Returns the _complete_ blocks that this bio covers.
692 */
693static void get_bio_block_range(struct thin_c *tc, struct bio *bio,
694 dm_block_t *begin, dm_block_t *end)
695{
696 struct pool *pool = tc->pool;
697 sector_t b = bio->bi_iter.bi_sector;
698 sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT);
699
700 b += pool->sectors_per_block - 1ull; /* so we round up */
701
702 if (block_size_is_power_of_two(pool)) {
703 b >>= pool->sectors_per_block_shift;
704 e >>= pool->sectors_per_block_shift;
705 } else {
706 (void) sector_div(b, pool->sectors_per_block);
707 (void) sector_div(e, pool->sectors_per_block);
708 }
709
710 if (e < b)
711 /* Can happen if the bio is within a single block. */
712 e = b;
713
714 *begin = b;
715 *end = e;
716}
717
718static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
719{
720 struct pool *pool = tc->pool;
721 sector_t bi_sector = bio->bi_iter.bi_sector;
722
723 bio_set_dev(bio, tc->pool_dev->bdev);
724 if (block_size_is_power_of_two(pool))
725 bio->bi_iter.bi_sector =
726 (block << pool->sectors_per_block_shift) |
727 (bi_sector & (pool->sectors_per_block - 1));
728 else
729 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
730 sector_div(bi_sector, pool->sectors_per_block);
731}
732
733static void remap_to_origin(struct thin_c *tc, struct bio *bio)
734{
735 bio_set_dev(bio, tc->origin_dev->bdev);
736}
737
738static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
739{
740 return op_is_flush(bio->bi_opf) &&
741 dm_thin_changed_this_transaction(tc->td);
742}
743
744static void inc_all_io_entry(struct pool *pool, struct bio *bio)
745{
746 struct dm_thin_endio_hook *h;
747
748 if (bio_op(bio) == REQ_OP_DISCARD)
749 return;
750
751 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
752 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
753}
754
755static void issue(struct thin_c *tc, struct bio *bio)
756{
757 struct pool *pool = tc->pool;
758
759 if (!bio_triggers_commit(tc, bio)) {
760 dm_submit_bio_remap(bio, NULL);
761 return;
762 }
763
764 /*
765 * Complete bio with an error if earlier I/O caused changes to
766 * the metadata that can't be committed e.g, due to I/O errors
767 * on the metadata device.
768 */
769 if (dm_thin_aborted_changes(tc->td)) {
770 bio_io_error(bio);
771 return;
772 }
773
774 /*
775 * Batch together any bios that trigger commits and then issue a
776 * single commit for them in process_deferred_bios().
777 */
778 spin_lock_irq(&pool->lock);
779 bio_list_add(&pool->deferred_flush_bios, bio);
780 spin_unlock_irq(&pool->lock);
781}
782
783static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
784{
785 remap_to_origin(tc, bio);
786 issue(tc, bio);
787}
788
789static void remap_and_issue(struct thin_c *tc, struct bio *bio,
790 dm_block_t block)
791{
792 remap(tc, bio, block);
793 issue(tc, bio);
794}
795
796/*----------------------------------------------------------------*/
797
798/*
799 * Bio endio functions.
800 */
801struct dm_thin_new_mapping {
802 struct list_head list;
803
804 bool pass_discard:1;
805 bool maybe_shared:1;
806
807 /*
808 * Track quiescing, copying and zeroing preparation actions. When this
809 * counter hits zero the block is prepared and can be inserted into the
810 * btree.
811 */
812 atomic_t prepare_actions;
813
814 blk_status_t status;
815 struct thin_c *tc;
816 dm_block_t virt_begin, virt_end;
817 dm_block_t data_block;
818 struct dm_bio_prison_cell *cell;
819
820 /*
821 * If the bio covers the whole area of a block then we can avoid
822 * zeroing or copying. Instead this bio is hooked. The bio will
823 * still be in the cell, so care has to be taken to avoid issuing
824 * the bio twice.
825 */
826 struct bio *bio;
827 bio_end_io_t *saved_bi_end_io;
828};
829
830static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
831{
832 struct pool *pool = m->tc->pool;
833
834 if (atomic_dec_and_test(&m->prepare_actions)) {
835 list_add_tail(&m->list, &pool->prepared_mappings);
836 wake_worker(pool);
837 }
838}
839
840static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
841{
842 unsigned long flags;
843 struct pool *pool = m->tc->pool;
844
845 spin_lock_irqsave(&pool->lock, flags);
846 __complete_mapping_preparation(m);
847 spin_unlock_irqrestore(&pool->lock, flags);
848}
849
850static void copy_complete(int read_err, unsigned long write_err, void *context)
851{
852 struct dm_thin_new_mapping *m = context;
853
854 m->status = read_err || write_err ? BLK_STS_IOERR : 0;
855 complete_mapping_preparation(m);
856}
857
858static void overwrite_endio(struct bio *bio)
859{
860 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
861 struct dm_thin_new_mapping *m = h->overwrite_mapping;
862
863 bio->bi_end_io = m->saved_bi_end_io;
864
865 m->status = bio->bi_status;
866 complete_mapping_preparation(m);
867}
868
869/*----------------------------------------------------------------*/
870
871/*
872 * Workqueue.
873 */
874
875/*
876 * Prepared mapping jobs.
877 */
878
879/*
880 * This sends the bios in the cell, except the original holder, back
881 * to the deferred_bios list.
882 */
883static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
884{
885 struct pool *pool = tc->pool;
886 unsigned long flags;
887 struct bio_list bios;
888
889 bio_list_init(&bios);
890 cell_release_no_holder(pool, cell, &bios);
891
892 if (!bio_list_empty(&bios)) {
893 spin_lock_irqsave(&tc->lock, flags);
894 bio_list_merge(&tc->deferred_bio_list, &bios);
895 spin_unlock_irqrestore(&tc->lock, flags);
896 wake_worker(pool);
897 }
898}
899
900static void thin_defer_bio(struct thin_c *tc, struct bio *bio);
901
902struct remap_info {
903 struct thin_c *tc;
904 struct bio_list defer_bios;
905 struct bio_list issue_bios;
906};
907
908static void __inc_remap_and_issue_cell(void *context,
909 struct dm_bio_prison_cell *cell)
910{
911 struct remap_info *info = context;
912 struct bio *bio;
913
914 while ((bio = bio_list_pop(&cell->bios))) {
915 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD)
916 bio_list_add(&info->defer_bios, bio);
917 else {
918 inc_all_io_entry(info->tc->pool, bio);
919
920 /*
921 * We can't issue the bios with the bio prison lock
922 * held, so we add them to a list to issue on
923 * return from this function.
924 */
925 bio_list_add(&info->issue_bios, bio);
926 }
927 }
928}
929
930static void inc_remap_and_issue_cell(struct thin_c *tc,
931 struct dm_bio_prison_cell *cell,
932 dm_block_t block)
933{
934 struct bio *bio;
935 struct remap_info info;
936
937 info.tc = tc;
938 bio_list_init(&info.defer_bios);
939 bio_list_init(&info.issue_bios);
940
941 /*
942 * We have to be careful to inc any bios we're about to issue
943 * before the cell is released, and avoid a race with new bios
944 * being added to the cell.
945 */
946 cell_visit_release(tc->pool, __inc_remap_and_issue_cell,
947 &info, cell);
948
949 while ((bio = bio_list_pop(&info.defer_bios)))
950 thin_defer_bio(tc, bio);
951
952 while ((bio = bio_list_pop(&info.issue_bios)))
953 remap_and_issue(info.tc, bio, block);
954}
955
956static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
957{
958 cell_error(m->tc->pool, m->cell);
959 list_del(&m->list);
960 mempool_free(m, &m->tc->pool->mapping_pool);
961}
962
963static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio)
964{
965 struct pool *pool = tc->pool;
966
967 /*
968 * If the bio has the REQ_FUA flag set we must commit the metadata
969 * before signaling its completion.
970 */
971 if (!bio_triggers_commit(tc, bio)) {
972 bio_endio(bio);
973 return;
974 }
975
976 /*
977 * Complete bio with an error if earlier I/O caused changes to the
978 * metadata that can't be committed, e.g, due to I/O errors on the
979 * metadata device.
980 */
981 if (dm_thin_aborted_changes(tc->td)) {
982 bio_io_error(bio);
983 return;
984 }
985
986 /*
987 * Batch together any bios that trigger commits and then issue a
988 * single commit for them in process_deferred_bios().
989 */
990 spin_lock_irq(&pool->lock);
991 bio_list_add(&pool->deferred_flush_completions, bio);
992 spin_unlock_irq(&pool->lock);
993}
994
995static void process_prepared_mapping(struct dm_thin_new_mapping *m)
996{
997 struct thin_c *tc = m->tc;
998 struct pool *pool = tc->pool;
999 struct bio *bio = m->bio;
1000 int r;
1001
1002 if (m->status) {
1003 cell_error(pool, m->cell);
1004 goto out;
1005 }
1006
1007 /*
1008 * Commit the prepared block into the mapping btree.
1009 * Any I/O for this block arriving after this point will get
1010 * remapped to it directly.
1011 */
1012 r = dm_thin_insert_block(tc->td, m->virt_begin, m->data_block);
1013 if (r) {
1014 metadata_operation_failed(pool, "dm_thin_insert_block", r);
1015 cell_error(pool, m->cell);
1016 goto out;
1017 }
1018
1019 /*
1020 * Release any bios held while the block was being provisioned.
1021 * If we are processing a write bio that completely covers the block,
1022 * we already processed it so can ignore it now when processing
1023 * the bios in the cell.
1024 */
1025 if (bio) {
1026 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1027 complete_overwrite_bio(tc, bio);
1028 } else {
1029 inc_all_io_entry(tc->pool, m->cell->holder);
1030 remap_and_issue(tc, m->cell->holder, m->data_block);
1031 inc_remap_and_issue_cell(tc, m->cell, m->data_block);
1032 }
1033
1034out:
1035 list_del(&m->list);
1036 mempool_free(m, &pool->mapping_pool);
1037}
1038
1039/*----------------------------------------------------------------*/
1040
1041static void free_discard_mapping(struct dm_thin_new_mapping *m)
1042{
1043 struct thin_c *tc = m->tc;
1044
1045 if (m->cell)
1046 cell_defer_no_holder(tc, m->cell);
1047 mempool_free(m, &tc->pool->mapping_pool);
1048}
1049
1050static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
1051{
1052 bio_io_error(m->bio);
1053 free_discard_mapping(m);
1054}
1055
1056static void process_prepared_discard_success(struct dm_thin_new_mapping *m)
1057{
1058 bio_endio(m->bio);
1059 free_discard_mapping(m);
1060}
1061
1062static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m)
1063{
1064 int r;
1065 struct thin_c *tc = m->tc;
1066
1067 r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end);
1068 if (r) {
1069 metadata_operation_failed(tc->pool, "dm_thin_remove_range", r);
1070 bio_io_error(m->bio);
1071 } else
1072 bio_endio(m->bio);
1073
1074 cell_defer_no_holder(tc, m->cell);
1075 mempool_free(m, &tc->pool->mapping_pool);
1076}
1077
1078/*----------------------------------------------------------------*/
1079
1080static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m,
1081 struct bio *discard_parent)
1082{
1083 /*
1084 * We've already unmapped this range of blocks, but before we
1085 * passdown we have to check that these blocks are now unused.
1086 */
1087 int r = 0;
1088 bool shared = true;
1089 struct thin_c *tc = m->tc;
1090 struct pool *pool = tc->pool;
1091 dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin;
1092 struct discard_op op;
1093
1094 begin_discard(&op, tc, discard_parent);
1095 while (b != end) {
1096 /* find start of unmapped run */
1097 for (; b < end; b++) {
1098 r = dm_pool_block_is_shared(pool->pmd, b, &shared);
1099 if (r)
1100 goto out;
1101
1102 if (!shared)
1103 break;
1104 }
1105
1106 if (b == end)
1107 break;
1108
1109 /* find end of run */
1110 for (e = b + 1; e != end; e++) {
1111 r = dm_pool_block_is_shared(pool->pmd, e, &shared);
1112 if (r)
1113 goto out;
1114
1115 if (shared)
1116 break;
1117 }
1118
1119 r = issue_discard(&op, b, e);
1120 if (r)
1121 goto out;
1122
1123 b = e;
1124 }
1125out:
1126 end_discard(&op, r);
1127}
1128
1129static void queue_passdown_pt2(struct dm_thin_new_mapping *m)
1130{
1131 unsigned long flags;
1132 struct pool *pool = m->tc->pool;
1133
1134 spin_lock_irqsave(&pool->lock, flags);
1135 list_add_tail(&m->list, &pool->prepared_discards_pt2);
1136 spin_unlock_irqrestore(&pool->lock, flags);
1137 wake_worker(pool);
1138}
1139
1140static void passdown_endio(struct bio *bio)
1141{
1142 /*
1143 * It doesn't matter if the passdown discard failed, we still want
1144 * to unmap (we ignore err).
1145 */
1146 queue_passdown_pt2(bio->bi_private);
1147 bio_put(bio);
1148}
1149
1150static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m)
1151{
1152 int r;
1153 struct thin_c *tc = m->tc;
1154 struct pool *pool = tc->pool;
1155 struct bio *discard_parent;
1156 dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin);
1157
1158 /*
1159 * Only this thread allocates blocks, so we can be sure that the
1160 * newly unmapped blocks will not be allocated before the end of
1161 * the function.
1162 */
1163 r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end);
1164 if (r) {
1165 metadata_operation_failed(pool, "dm_thin_remove_range", r);
1166 bio_io_error(m->bio);
1167 cell_defer_no_holder(tc, m->cell);
1168 mempool_free(m, &pool->mapping_pool);
1169 return;
1170 }
1171
1172 /*
1173 * Increment the unmapped blocks. This prevents a race between the
1174 * passdown io and reallocation of freed blocks.
1175 */
1176 r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
1177 if (r) {
1178 metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
1179 bio_io_error(m->bio);
1180 cell_defer_no_holder(tc, m->cell);
1181 mempool_free(m, &pool->mapping_pool);
1182 return;
1183 }
1184
1185 discard_parent = bio_alloc(NULL, 1, 0, GFP_NOIO);
1186 discard_parent->bi_end_io = passdown_endio;
1187 discard_parent->bi_private = m;
1188 if (m->maybe_shared)
1189 passdown_double_checking_shared_status(m, discard_parent);
1190 else {
1191 struct discard_op op;
1192
1193 begin_discard(&op, tc, discard_parent);
1194 r = issue_discard(&op, m->data_block, data_end);
1195 end_discard(&op, r);
1196 }
1197}
1198
1199static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m)
1200{
1201 int r;
1202 struct thin_c *tc = m->tc;
1203 struct pool *pool = tc->pool;
1204
1205 /*
1206 * The passdown has completed, so now we can decrement all those
1207 * unmapped blocks.
1208 */
1209 r = dm_pool_dec_data_range(pool->pmd, m->data_block,
1210 m->data_block + (m->virt_end - m->virt_begin));
1211 if (r) {
1212 metadata_operation_failed(pool, "dm_pool_dec_data_range", r);
1213 bio_io_error(m->bio);
1214 } else
1215 bio_endio(m->bio);
1216
1217 cell_defer_no_holder(tc, m->cell);
1218 mempool_free(m, &pool->mapping_pool);
1219}
1220
1221static void process_prepared(struct pool *pool, struct list_head *head,
1222 process_mapping_fn *fn)
1223{
1224 struct list_head maps;
1225 struct dm_thin_new_mapping *m, *tmp;
1226
1227 INIT_LIST_HEAD(&maps);
1228 spin_lock_irq(&pool->lock);
1229 list_splice_init(head, &maps);
1230 spin_unlock_irq(&pool->lock);
1231
1232 list_for_each_entry_safe(m, tmp, &maps, list)
1233 (*fn)(m);
1234}
1235
1236/*
1237 * Deferred bio jobs.
1238 */
1239static int io_overlaps_block(struct pool *pool, struct bio *bio)
1240{
1241 return bio->bi_iter.bi_size ==
1242 (pool->sectors_per_block << SECTOR_SHIFT);
1243}
1244
1245static int io_overwrites_block(struct pool *pool, struct bio *bio)
1246{
1247 return (bio_data_dir(bio) == WRITE) &&
1248 io_overlaps_block(pool, bio);
1249}
1250
1251static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
1252 bio_end_io_t *fn)
1253{
1254 *save = bio->bi_end_io;
1255 bio->bi_end_io = fn;
1256}
1257
1258static int ensure_next_mapping(struct pool *pool)
1259{
1260 if (pool->next_mapping)
1261 return 0;
1262
1263 pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC);
1264
1265 return pool->next_mapping ? 0 : -ENOMEM;
1266}
1267
1268static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
1269{
1270 struct dm_thin_new_mapping *m = pool->next_mapping;
1271
1272 BUG_ON(!pool->next_mapping);
1273
1274 memset(m, 0, sizeof(struct dm_thin_new_mapping));
1275 INIT_LIST_HEAD(&m->list);
1276 m->bio = NULL;
1277
1278 pool->next_mapping = NULL;
1279
1280 return m;
1281}
1282
1283static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
1284 sector_t begin, sector_t end)
1285{
1286 struct dm_io_region to;
1287
1288 to.bdev = tc->pool_dev->bdev;
1289 to.sector = begin;
1290 to.count = end - begin;
1291
1292 dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
1293}
1294
1295static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
1296 dm_block_t data_begin,
1297 struct dm_thin_new_mapping *m)
1298{
1299 struct pool *pool = tc->pool;
1300 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1301
1302 h->overwrite_mapping = m;
1303 m->bio = bio;
1304 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
1305 inc_all_io_entry(pool, bio);
1306 remap_and_issue(tc, bio, data_begin);
1307}
1308
1309/*
1310 * A partial copy also needs to zero the uncopied region.
1311 */
1312static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
1313 struct dm_dev *origin, dm_block_t data_origin,
1314 dm_block_t data_dest,
1315 struct dm_bio_prison_cell *cell, struct bio *bio,
1316 sector_t len)
1317{
1318 struct pool *pool = tc->pool;
1319 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1320
1321 m->tc = tc;
1322 m->virt_begin = virt_block;
1323 m->virt_end = virt_block + 1u;
1324 m->data_block = data_dest;
1325 m->cell = cell;
1326
1327 /*
1328 * quiesce action + copy action + an extra reference held for the
1329 * duration of this function (we may need to inc later for a
1330 * partial zero).
1331 */
1332 atomic_set(&m->prepare_actions, 3);
1333
1334 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
1335 complete_mapping_preparation(m); /* already quiesced */
1336
1337 /*
1338 * IO to pool_dev remaps to the pool target's data_dev.
1339 *
1340 * If the whole block of data is being overwritten, we can issue the
1341 * bio immediately. Otherwise we use kcopyd to clone the data first.
1342 */
1343 if (io_overwrites_block(pool, bio))
1344 remap_and_issue_overwrite(tc, bio, data_dest, m);
1345 else {
1346 struct dm_io_region from, to;
1347
1348 from.bdev = origin->bdev;
1349 from.sector = data_origin * pool->sectors_per_block;
1350 from.count = len;
1351
1352 to.bdev = tc->pool_dev->bdev;
1353 to.sector = data_dest * pool->sectors_per_block;
1354 to.count = len;
1355
1356 dm_kcopyd_copy(pool->copier, &from, 1, &to,
1357 0, copy_complete, m);
1358
1359 /*
1360 * Do we need to zero a tail region?
1361 */
1362 if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
1363 atomic_inc(&m->prepare_actions);
1364 ll_zero(tc, m,
1365 data_dest * pool->sectors_per_block + len,
1366 (data_dest + 1) * pool->sectors_per_block);
1367 }
1368 }
1369
1370 complete_mapping_preparation(m); /* drop our ref */
1371}
1372
1373static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
1374 dm_block_t data_origin, dm_block_t data_dest,
1375 struct dm_bio_prison_cell *cell, struct bio *bio)
1376{
1377 schedule_copy(tc, virt_block, tc->pool_dev,
1378 data_origin, data_dest, cell, bio,
1379 tc->pool->sectors_per_block);
1380}
1381
1382static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
1383 dm_block_t data_block, struct dm_bio_prison_cell *cell,
1384 struct bio *bio)
1385{
1386 struct pool *pool = tc->pool;
1387 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1388
1389 atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
1390 m->tc = tc;
1391 m->virt_begin = virt_block;
1392 m->virt_end = virt_block + 1u;
1393 m->data_block = data_block;
1394 m->cell = cell;
1395
1396 /*
1397 * If the whole block of data is being overwritten or we are not
1398 * zeroing pre-existing data, we can issue the bio immediately.
1399 * Otherwise we use kcopyd to zero the data first.
1400 */
1401 if (pool->pf.zero_new_blocks) {
1402 if (io_overwrites_block(pool, bio))
1403 remap_and_issue_overwrite(tc, bio, data_block, m);
1404 else
1405 ll_zero(tc, m, data_block * pool->sectors_per_block,
1406 (data_block + 1) * pool->sectors_per_block);
1407 } else
1408 process_prepared_mapping(m);
1409}
1410
1411static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
1412 dm_block_t data_dest,
1413 struct dm_bio_prison_cell *cell, struct bio *bio)
1414{
1415 struct pool *pool = tc->pool;
1416 sector_t virt_block_begin = virt_block * pool->sectors_per_block;
1417 sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
1418
1419 if (virt_block_end <= tc->origin_size)
1420 schedule_copy(tc, virt_block, tc->origin_dev,
1421 virt_block, data_dest, cell, bio,
1422 pool->sectors_per_block);
1423
1424 else if (virt_block_begin < tc->origin_size)
1425 schedule_copy(tc, virt_block, tc->origin_dev,
1426 virt_block, data_dest, cell, bio,
1427 tc->origin_size - virt_block_begin);
1428
1429 else
1430 schedule_zero(tc, virt_block, data_dest, cell, bio);
1431}
1432
1433static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
1434
1435static void requeue_bios(struct pool *pool);
1436
1437static bool is_read_only_pool_mode(enum pool_mode mode)
1438{
1439 return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY);
1440}
1441
1442static bool is_read_only(struct pool *pool)
1443{
1444 return is_read_only_pool_mode(get_pool_mode(pool));
1445}
1446
1447static void check_for_metadata_space(struct pool *pool)
1448{
1449 int r;
1450 const char *ooms_reason = NULL;
1451 dm_block_t nr_free;
1452
1453 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free);
1454 if (r)
1455 ooms_reason = "Could not get free metadata blocks";
1456 else if (!nr_free)
1457 ooms_reason = "No free metadata blocks";
1458
1459 if (ooms_reason && !is_read_only(pool)) {
1460 DMERR("%s", ooms_reason);
1461 set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE);
1462 }
1463}
1464
1465static void check_for_data_space(struct pool *pool)
1466{
1467 int r;
1468 dm_block_t nr_free;
1469
1470 if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
1471 return;
1472
1473 r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
1474 if (r)
1475 return;
1476
1477 if (nr_free) {
1478 set_pool_mode(pool, PM_WRITE);
1479 requeue_bios(pool);
1480 }
1481}
1482
1483/*
1484 * A non-zero return indicates read_only or fail_io mode.
1485 * Many callers don't care about the return value.
1486 */
1487static int commit(struct pool *pool)
1488{
1489 int r;
1490
1491 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE)
1492 return -EINVAL;
1493
1494 r = dm_pool_commit_metadata(pool->pmd);
1495 if (r)
1496 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
1497 else {
1498 check_for_metadata_space(pool);
1499 check_for_data_space(pool);
1500 }
1501
1502 return r;
1503}
1504
1505static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
1506{
1507 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
1508 DMWARN("%s: reached low water mark for data device: sending event.",
1509 dm_device_name(pool->pool_md));
1510 spin_lock_irq(&pool->lock);
1511 pool->low_water_triggered = true;
1512 spin_unlock_irq(&pool->lock);
1513 dm_table_event(pool->ti->table);
1514 }
1515}
1516
1517static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
1518{
1519 int r;
1520 dm_block_t free_blocks;
1521 struct pool *pool = tc->pool;
1522
1523 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
1524 return -EINVAL;
1525
1526 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1527 if (r) {
1528 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1529 return r;
1530 }
1531
1532 check_low_water_mark(pool, free_blocks);
1533
1534 if (!free_blocks) {
1535 /*
1536 * Try to commit to see if that will free up some
1537 * more space.
1538 */
1539 r = commit(pool);
1540 if (r)
1541 return r;
1542
1543 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
1544 if (r) {
1545 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
1546 return r;
1547 }
1548
1549 if (!free_blocks) {
1550 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1551 return -ENOSPC;
1552 }
1553 }
1554
1555 r = dm_pool_alloc_data_block(pool->pmd, result);
1556 if (r) {
1557 if (r == -ENOSPC)
1558 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1559 else
1560 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1561 return r;
1562 }
1563
1564 r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks);
1565 if (r) {
1566 metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r);
1567 return r;
1568 }
1569
1570 if (!free_blocks) {
1571 /* Let's commit before we use up the metadata reserve. */
1572 r = commit(pool);
1573 if (r)
1574 return r;
1575 }
1576
1577 return 0;
1578}
1579
1580/*
1581 * If we have run out of space, queue bios until the device is
1582 * resumed, presumably after having been reloaded with more space.
1583 */
1584static void retry_on_resume(struct bio *bio)
1585{
1586 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1587 struct thin_c *tc = h->tc;
1588
1589 spin_lock_irq(&tc->lock);
1590 bio_list_add(&tc->retry_on_resume_list, bio);
1591 spin_unlock_irq(&tc->lock);
1592}
1593
1594static blk_status_t should_error_unserviceable_bio(struct pool *pool)
1595{
1596 enum pool_mode m = get_pool_mode(pool);
1597
1598 switch (m) {
1599 case PM_WRITE:
1600 /* Shouldn't get here */
1601 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1602 return BLK_STS_IOERR;
1603
1604 case PM_OUT_OF_DATA_SPACE:
1605 return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0;
1606
1607 case PM_OUT_OF_METADATA_SPACE:
1608 case PM_READ_ONLY:
1609 case PM_FAIL:
1610 return BLK_STS_IOERR;
1611 default:
1612 /* Shouldn't get here */
1613 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1614 return BLK_STS_IOERR;
1615 }
1616}
1617
1618static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1619{
1620 blk_status_t error = should_error_unserviceable_bio(pool);
1621
1622 if (error) {
1623 bio->bi_status = error;
1624 bio_endio(bio);
1625 } else
1626 retry_on_resume(bio);
1627}
1628
1629static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1630{
1631 struct bio *bio;
1632 struct bio_list bios;
1633 blk_status_t error;
1634
1635 error = should_error_unserviceable_bio(pool);
1636 if (error) {
1637 cell_error_with_code(pool, cell, error);
1638 return;
1639 }
1640
1641 bio_list_init(&bios);
1642 cell_release(pool, cell, &bios);
1643
1644 while ((bio = bio_list_pop(&bios)))
1645 retry_on_resume(bio);
1646}
1647
1648static void process_discard_cell_no_passdown(struct thin_c *tc,
1649 struct dm_bio_prison_cell *virt_cell)
1650{
1651 struct pool *pool = tc->pool;
1652 struct dm_thin_new_mapping *m = get_next_mapping(pool);
1653
1654 /*
1655 * We don't need to lock the data blocks, since there's no
1656 * passdown. We only lock data blocks for allocation and breaking sharing.
1657 */
1658 m->tc = tc;
1659 m->virt_begin = virt_cell->key.block_begin;
1660 m->virt_end = virt_cell->key.block_end;
1661 m->cell = virt_cell;
1662 m->bio = virt_cell->holder;
1663
1664 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1665 pool->process_prepared_discard(m);
1666}
1667
1668static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end,
1669 struct bio *bio)
1670{
1671 struct pool *pool = tc->pool;
1672
1673 int r;
1674 bool maybe_shared;
1675 struct dm_cell_key data_key;
1676 struct dm_bio_prison_cell *data_cell;
1677 struct dm_thin_new_mapping *m;
1678 dm_block_t virt_begin, virt_end, data_begin, data_end;
1679 dm_block_t len, next_boundary;
1680
1681 while (begin != end) {
1682 r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end,
1683 &data_begin, &maybe_shared);
1684 if (r) {
1685 /*
1686 * Silently fail, letting any mappings we've
1687 * created complete.
1688 */
1689 break;
1690 }
1691
1692 data_end = data_begin + (virt_end - virt_begin);
1693
1694 /*
1695 * Make sure the data region obeys the bio prison restrictions.
1696 */
1697 while (data_begin < data_end) {
1698 r = ensure_next_mapping(pool);
1699 if (r)
1700 return; /* we did our best */
1701
1702 next_boundary = ((data_begin >> BIO_PRISON_MAX_RANGE_SHIFT) + 1)
1703 << BIO_PRISON_MAX_RANGE_SHIFT;
1704 len = min_t(sector_t, data_end - data_begin, next_boundary - data_begin);
1705
1706 /* This key is certainly within range given the above splitting */
1707 (void) build_key(tc->td, PHYSICAL, data_begin, data_begin + len, &data_key);
1708 if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) {
1709 /* contention, we'll give up with this range */
1710 data_begin += len;
1711 continue;
1712 }
1713
1714 /*
1715 * IO may still be going to the destination block. We must
1716 * quiesce before we can do the removal.
1717 */
1718 m = get_next_mapping(pool);
1719 m->tc = tc;
1720 m->maybe_shared = maybe_shared;
1721 m->virt_begin = virt_begin;
1722 m->virt_end = virt_begin + len;
1723 m->data_block = data_begin;
1724 m->cell = data_cell;
1725 m->bio = bio;
1726
1727 /*
1728 * The parent bio must not complete before sub discard bios are
1729 * chained to it (see end_discard's bio_chain)!
1730 *
1731 * This per-mapping bi_remaining increment is paired with
1732 * the implicit decrement that occurs via bio_endio() in
1733 * end_discard().
1734 */
1735 bio_inc_remaining(bio);
1736 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
1737 pool->process_prepared_discard(m);
1738
1739 virt_begin += len;
1740 data_begin += len;
1741 }
1742
1743 begin = virt_end;
1744 }
1745}
1746
1747static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell)
1748{
1749 struct bio *bio = virt_cell->holder;
1750 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1751
1752 /*
1753 * The virt_cell will only get freed once the origin bio completes.
1754 * This means it will remain locked while all the individual
1755 * passdown bios are in flight.
1756 */
1757 h->cell = virt_cell;
1758 break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio);
1759
1760 /*
1761 * We complete the bio now, knowing that the bi_remaining field
1762 * will prevent completion until the sub range discards have
1763 * completed.
1764 */
1765 bio_endio(bio);
1766}
1767
1768static void process_discard_bio(struct thin_c *tc, struct bio *bio)
1769{
1770 dm_block_t begin, end;
1771 struct dm_cell_key virt_key;
1772 struct dm_bio_prison_cell *virt_cell;
1773
1774 get_bio_block_range(tc, bio, &begin, &end);
1775 if (begin == end) {
1776 /*
1777 * The discard covers less than a block.
1778 */
1779 bio_endio(bio);
1780 return;
1781 }
1782
1783 if (unlikely(!build_key(tc->td, VIRTUAL, begin, end, &virt_key))) {
1784 DMERR_LIMIT("Discard doesn't respect bio prison limits");
1785 bio_endio(bio);
1786 return;
1787 }
1788
1789 if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) {
1790 /*
1791 * Potential starvation issue: We're relying on the
1792 * fs/application being well behaved, and not trying to
1793 * send IO to a region at the same time as discarding it.
1794 * If they do this persistently then it's possible this
1795 * cell will never be granted.
1796 */
1797 return;
1798 }
1799
1800 tc->pool->process_discard_cell(tc, virt_cell);
1801}
1802
1803static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1804 struct dm_cell_key *key,
1805 struct dm_thin_lookup_result *lookup_result,
1806 struct dm_bio_prison_cell *cell)
1807{
1808 int r;
1809 dm_block_t data_block;
1810 struct pool *pool = tc->pool;
1811
1812 r = alloc_data_block(tc, &data_block);
1813 switch (r) {
1814 case 0:
1815 schedule_internal_copy(tc, block, lookup_result->block,
1816 data_block, cell, bio);
1817 break;
1818
1819 case -ENOSPC:
1820 retry_bios_on_resume(pool, cell);
1821 break;
1822
1823 default:
1824 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1825 __func__, r);
1826 cell_error(pool, cell);
1827 break;
1828 }
1829}
1830
1831static void __remap_and_issue_shared_cell(void *context,
1832 struct dm_bio_prison_cell *cell)
1833{
1834 struct remap_info *info = context;
1835 struct bio *bio;
1836
1837 while ((bio = bio_list_pop(&cell->bios))) {
1838 if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) ||
1839 bio_op(bio) == REQ_OP_DISCARD)
1840 bio_list_add(&info->defer_bios, bio);
1841 else {
1842 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1843
1844 h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds);
1845 inc_all_io_entry(info->tc->pool, bio);
1846 bio_list_add(&info->issue_bios, bio);
1847 }
1848 }
1849}
1850
1851static void remap_and_issue_shared_cell(struct thin_c *tc,
1852 struct dm_bio_prison_cell *cell,
1853 dm_block_t block)
1854{
1855 struct bio *bio;
1856 struct remap_info info;
1857
1858 info.tc = tc;
1859 bio_list_init(&info.defer_bios);
1860 bio_list_init(&info.issue_bios);
1861
1862 cell_visit_release(tc->pool, __remap_and_issue_shared_cell,
1863 &info, cell);
1864
1865 while ((bio = bio_list_pop(&info.defer_bios)))
1866 thin_defer_bio(tc, bio);
1867
1868 while ((bio = bio_list_pop(&info.issue_bios)))
1869 remap_and_issue(tc, bio, block);
1870}
1871
1872static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1873 dm_block_t block,
1874 struct dm_thin_lookup_result *lookup_result,
1875 struct dm_bio_prison_cell *virt_cell)
1876{
1877 struct dm_bio_prison_cell *data_cell;
1878 struct pool *pool = tc->pool;
1879 struct dm_cell_key key;
1880
1881 /*
1882 * If cell is already occupied, then sharing is already in the process
1883 * of being broken so we have nothing further to do here.
1884 */
1885 build_data_key(tc->td, lookup_result->block, &key);
1886 if (bio_detain(pool, &key, bio, &data_cell)) {
1887 cell_defer_no_holder(tc, virt_cell);
1888 return;
1889 }
1890
1891 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) {
1892 break_sharing(tc, bio, block, &key, lookup_result, data_cell);
1893 cell_defer_no_holder(tc, virt_cell);
1894 } else {
1895 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1896
1897 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1898 inc_all_io_entry(pool, bio);
1899 remap_and_issue(tc, bio, lookup_result->block);
1900
1901 remap_and_issue_shared_cell(tc, data_cell, lookup_result->block);
1902 remap_and_issue_shared_cell(tc, virt_cell, lookup_result->block);
1903 }
1904}
1905
1906static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1907 struct dm_bio_prison_cell *cell)
1908{
1909 int r;
1910 dm_block_t data_block;
1911 struct pool *pool = tc->pool;
1912
1913 /*
1914 * Remap empty bios (flushes) immediately, without provisioning.
1915 */
1916 if (!bio->bi_iter.bi_size) {
1917 inc_all_io_entry(pool, bio);
1918 cell_defer_no_holder(tc, cell);
1919
1920 remap_and_issue(tc, bio, 0);
1921 return;
1922 }
1923
1924 /*
1925 * Fill read bios with zeroes and complete them immediately.
1926 */
1927 if (bio_data_dir(bio) == READ) {
1928 zero_fill_bio(bio);
1929 cell_defer_no_holder(tc, cell);
1930 bio_endio(bio);
1931 return;
1932 }
1933
1934 r = alloc_data_block(tc, &data_block);
1935 switch (r) {
1936 case 0:
1937 if (tc->origin_dev)
1938 schedule_external_copy(tc, block, data_block, cell, bio);
1939 else
1940 schedule_zero(tc, block, data_block, cell, bio);
1941 break;
1942
1943 case -ENOSPC:
1944 retry_bios_on_resume(pool, cell);
1945 break;
1946
1947 default:
1948 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1949 __func__, r);
1950 cell_error(pool, cell);
1951 break;
1952 }
1953}
1954
1955static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
1956{
1957 int r;
1958 struct pool *pool = tc->pool;
1959 struct bio *bio = cell->holder;
1960 dm_block_t block = get_bio_block(tc, bio);
1961 struct dm_thin_lookup_result lookup_result;
1962
1963 if (tc->requeue_mode) {
1964 cell_requeue(pool, cell);
1965 return;
1966 }
1967
1968 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1969 switch (r) {
1970 case 0:
1971 if (lookup_result.shared)
1972 process_shared_bio(tc, bio, block, &lookup_result, cell);
1973 else {
1974 inc_all_io_entry(pool, bio);
1975 remap_and_issue(tc, bio, lookup_result.block);
1976 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
1977 }
1978 break;
1979
1980 case -ENODATA:
1981 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1982 inc_all_io_entry(pool, bio);
1983 cell_defer_no_holder(tc, cell);
1984
1985 if (bio_end_sector(bio) <= tc->origin_size)
1986 remap_to_origin_and_issue(tc, bio);
1987
1988 else if (bio->bi_iter.bi_sector < tc->origin_size) {
1989 zero_fill_bio(bio);
1990 bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT;
1991 remap_to_origin_and_issue(tc, bio);
1992
1993 } else {
1994 zero_fill_bio(bio);
1995 bio_endio(bio);
1996 }
1997 } else
1998 provision_block(tc, bio, block, cell);
1999 break;
2000
2001 default:
2002 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2003 __func__, r);
2004 cell_defer_no_holder(tc, cell);
2005 bio_io_error(bio);
2006 break;
2007 }
2008}
2009
2010static void process_bio(struct thin_c *tc, struct bio *bio)
2011{
2012 struct pool *pool = tc->pool;
2013 dm_block_t block = get_bio_block(tc, bio);
2014 struct dm_bio_prison_cell *cell;
2015 struct dm_cell_key key;
2016
2017 /*
2018 * If cell is already occupied, then the block is already
2019 * being provisioned so we have nothing further to do here.
2020 */
2021 build_virtual_key(tc->td, block, &key);
2022 if (bio_detain(pool, &key, bio, &cell))
2023 return;
2024
2025 process_cell(tc, cell);
2026}
2027
2028static void __process_bio_read_only(struct thin_c *tc, struct bio *bio,
2029 struct dm_bio_prison_cell *cell)
2030{
2031 int r;
2032 int rw = bio_data_dir(bio);
2033 dm_block_t block = get_bio_block(tc, bio);
2034 struct dm_thin_lookup_result lookup_result;
2035
2036 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
2037 switch (r) {
2038 case 0:
2039 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) {
2040 handle_unserviceable_bio(tc->pool, bio);
2041 if (cell)
2042 cell_defer_no_holder(tc, cell);
2043 } else {
2044 inc_all_io_entry(tc->pool, bio);
2045 remap_and_issue(tc, bio, lookup_result.block);
2046 if (cell)
2047 inc_remap_and_issue_cell(tc, cell, lookup_result.block);
2048 }
2049 break;
2050
2051 case -ENODATA:
2052 if (cell)
2053 cell_defer_no_holder(tc, cell);
2054 if (rw != READ) {
2055 handle_unserviceable_bio(tc->pool, bio);
2056 break;
2057 }
2058
2059 if (tc->origin_dev) {
2060 inc_all_io_entry(tc->pool, bio);
2061 remap_to_origin_and_issue(tc, bio);
2062 break;
2063 }
2064
2065 zero_fill_bio(bio);
2066 bio_endio(bio);
2067 break;
2068
2069 default:
2070 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
2071 __func__, r);
2072 if (cell)
2073 cell_defer_no_holder(tc, cell);
2074 bio_io_error(bio);
2075 break;
2076 }
2077}
2078
2079static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
2080{
2081 __process_bio_read_only(tc, bio, NULL);
2082}
2083
2084static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2085{
2086 __process_bio_read_only(tc, cell->holder, cell);
2087}
2088
2089static void process_bio_success(struct thin_c *tc, struct bio *bio)
2090{
2091 bio_endio(bio);
2092}
2093
2094static void process_bio_fail(struct thin_c *tc, struct bio *bio)
2095{
2096 bio_io_error(bio);
2097}
2098
2099static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2100{
2101 cell_success(tc->pool, cell);
2102}
2103
2104static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2105{
2106 cell_error(tc->pool, cell);
2107}
2108
2109/*
2110 * FIXME: should we also commit due to size of transaction, measured in
2111 * metadata blocks?
2112 */
2113static int need_commit_due_to_time(struct pool *pool)
2114{
2115 return !time_in_range(jiffies, pool->last_commit_jiffies,
2116 pool->last_commit_jiffies + COMMIT_PERIOD);
2117}
2118
2119#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
2120#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
2121
2122static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
2123{
2124 struct rb_node **rbp, *parent;
2125 struct dm_thin_endio_hook *pbd;
2126 sector_t bi_sector = bio->bi_iter.bi_sector;
2127
2128 rbp = &tc->sort_bio_list.rb_node;
2129 parent = NULL;
2130 while (*rbp) {
2131 parent = *rbp;
2132 pbd = thin_pbd(parent);
2133
2134 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
2135 rbp = &(*rbp)->rb_left;
2136 else
2137 rbp = &(*rbp)->rb_right;
2138 }
2139
2140 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2141 rb_link_node(&pbd->rb_node, parent, rbp);
2142 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
2143}
2144
2145static void __extract_sorted_bios(struct thin_c *tc)
2146{
2147 struct rb_node *node;
2148 struct dm_thin_endio_hook *pbd;
2149 struct bio *bio;
2150
2151 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
2152 pbd = thin_pbd(node);
2153 bio = thin_bio(pbd);
2154
2155 bio_list_add(&tc->deferred_bio_list, bio);
2156 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
2157 }
2158
2159 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
2160}
2161
2162static void __sort_thin_deferred_bios(struct thin_c *tc)
2163{
2164 struct bio *bio;
2165 struct bio_list bios;
2166
2167 bio_list_init(&bios);
2168 bio_list_merge(&bios, &tc->deferred_bio_list);
2169 bio_list_init(&tc->deferred_bio_list);
2170
2171 /* Sort deferred_bio_list using rb-tree */
2172 while ((bio = bio_list_pop(&bios)))
2173 __thin_bio_rb_add(tc, bio);
2174
2175 /*
2176 * Transfer the sorted bios in sort_bio_list back to
2177 * deferred_bio_list to allow lockless submission of
2178 * all bios.
2179 */
2180 __extract_sorted_bios(tc);
2181}
2182
2183static void process_thin_deferred_bios(struct thin_c *tc)
2184{
2185 struct pool *pool = tc->pool;
2186 struct bio *bio;
2187 struct bio_list bios;
2188 struct blk_plug plug;
2189 unsigned int count = 0;
2190
2191 if (tc->requeue_mode) {
2192 error_thin_bio_list(tc, &tc->deferred_bio_list,
2193 BLK_STS_DM_REQUEUE);
2194 return;
2195 }
2196
2197 bio_list_init(&bios);
2198
2199 spin_lock_irq(&tc->lock);
2200
2201 if (bio_list_empty(&tc->deferred_bio_list)) {
2202 spin_unlock_irq(&tc->lock);
2203 return;
2204 }
2205
2206 __sort_thin_deferred_bios(tc);
2207
2208 bio_list_merge(&bios, &tc->deferred_bio_list);
2209 bio_list_init(&tc->deferred_bio_list);
2210
2211 spin_unlock_irq(&tc->lock);
2212
2213 blk_start_plug(&plug);
2214 while ((bio = bio_list_pop(&bios))) {
2215 /*
2216 * If we've got no free new_mapping structs, and processing
2217 * this bio might require one, we pause until there are some
2218 * prepared mappings to process.
2219 */
2220 if (ensure_next_mapping(pool)) {
2221 spin_lock_irq(&tc->lock);
2222 bio_list_add(&tc->deferred_bio_list, bio);
2223 bio_list_merge(&tc->deferred_bio_list, &bios);
2224 spin_unlock_irq(&tc->lock);
2225 break;
2226 }
2227
2228 if (bio_op(bio) == REQ_OP_DISCARD)
2229 pool->process_discard(tc, bio);
2230 else
2231 pool->process_bio(tc, bio);
2232
2233 if ((count++ & 127) == 0) {
2234 throttle_work_update(&pool->throttle);
2235 dm_pool_issue_prefetches(pool->pmd);
2236 }
2237 cond_resched();
2238 }
2239 blk_finish_plug(&plug);
2240}
2241
2242static int cmp_cells(const void *lhs, const void *rhs)
2243{
2244 struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs);
2245 struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs);
2246
2247 BUG_ON(!lhs_cell->holder);
2248 BUG_ON(!rhs_cell->holder);
2249
2250 if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector)
2251 return -1;
2252
2253 if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector)
2254 return 1;
2255
2256 return 0;
2257}
2258
2259static unsigned int sort_cells(struct pool *pool, struct list_head *cells)
2260{
2261 unsigned int count = 0;
2262 struct dm_bio_prison_cell *cell, *tmp;
2263
2264 list_for_each_entry_safe(cell, tmp, cells, user_list) {
2265 if (count >= CELL_SORT_ARRAY_SIZE)
2266 break;
2267
2268 pool->cell_sort_array[count++] = cell;
2269 list_del(&cell->user_list);
2270 }
2271
2272 sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL);
2273
2274 return count;
2275}
2276
2277static void process_thin_deferred_cells(struct thin_c *tc)
2278{
2279 struct pool *pool = tc->pool;
2280 struct list_head cells;
2281 struct dm_bio_prison_cell *cell;
2282 unsigned int i, j, count;
2283
2284 INIT_LIST_HEAD(&cells);
2285
2286 spin_lock_irq(&tc->lock);
2287 list_splice_init(&tc->deferred_cells, &cells);
2288 spin_unlock_irq(&tc->lock);
2289
2290 if (list_empty(&cells))
2291 return;
2292
2293 do {
2294 count = sort_cells(tc->pool, &cells);
2295
2296 for (i = 0; i < count; i++) {
2297 cell = pool->cell_sort_array[i];
2298 BUG_ON(!cell->holder);
2299
2300 /*
2301 * If we've got no free new_mapping structs, and processing
2302 * this bio might require one, we pause until there are some
2303 * prepared mappings to process.
2304 */
2305 if (ensure_next_mapping(pool)) {
2306 for (j = i; j < count; j++)
2307 list_add(&pool->cell_sort_array[j]->user_list, &cells);
2308
2309 spin_lock_irq(&tc->lock);
2310 list_splice(&cells, &tc->deferred_cells);
2311 spin_unlock_irq(&tc->lock);
2312 return;
2313 }
2314
2315 if (bio_op(cell->holder) == REQ_OP_DISCARD)
2316 pool->process_discard_cell(tc, cell);
2317 else
2318 pool->process_cell(tc, cell);
2319 }
2320 cond_resched();
2321 } while (!list_empty(&cells));
2322}
2323
2324static void thin_get(struct thin_c *tc);
2325static void thin_put(struct thin_c *tc);
2326
2327/*
2328 * We can't hold rcu_read_lock() around code that can block. So we
2329 * find a thin with the rcu lock held; bump a refcount; then drop
2330 * the lock.
2331 */
2332static struct thin_c *get_first_thin(struct pool *pool)
2333{
2334 struct thin_c *tc = NULL;
2335
2336 rcu_read_lock();
2337 if (!list_empty(&pool->active_thins)) {
2338 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
2339 thin_get(tc);
2340 }
2341 rcu_read_unlock();
2342
2343 return tc;
2344}
2345
2346static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
2347{
2348 struct thin_c *old_tc = tc;
2349
2350 rcu_read_lock();
2351 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
2352 thin_get(tc);
2353 thin_put(old_tc);
2354 rcu_read_unlock();
2355 return tc;
2356 }
2357 thin_put(old_tc);
2358 rcu_read_unlock();
2359
2360 return NULL;
2361}
2362
2363static void process_deferred_bios(struct pool *pool)
2364{
2365 struct bio *bio;
2366 struct bio_list bios, bio_completions;
2367 struct thin_c *tc;
2368
2369 tc = get_first_thin(pool);
2370 while (tc) {
2371 process_thin_deferred_cells(tc);
2372 process_thin_deferred_bios(tc);
2373 tc = get_next_thin(pool, tc);
2374 }
2375
2376 /*
2377 * If there are any deferred flush bios, we must commit the metadata
2378 * before issuing them or signaling their completion.
2379 */
2380 bio_list_init(&bios);
2381 bio_list_init(&bio_completions);
2382
2383 spin_lock_irq(&pool->lock);
2384 bio_list_merge(&bios, &pool->deferred_flush_bios);
2385 bio_list_init(&pool->deferred_flush_bios);
2386
2387 bio_list_merge(&bio_completions, &pool->deferred_flush_completions);
2388 bio_list_init(&pool->deferred_flush_completions);
2389 spin_unlock_irq(&pool->lock);
2390
2391 if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) &&
2392 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
2393 return;
2394
2395 if (commit(pool)) {
2396 bio_list_merge(&bios, &bio_completions);
2397
2398 while ((bio = bio_list_pop(&bios)))
2399 bio_io_error(bio);
2400 return;
2401 }
2402 pool->last_commit_jiffies = jiffies;
2403
2404 while ((bio = bio_list_pop(&bio_completions)))
2405 bio_endio(bio);
2406
2407 while ((bio = bio_list_pop(&bios))) {
2408 /*
2409 * The data device was flushed as part of metadata commit,
2410 * so complete redundant flushes immediately.
2411 */
2412 if (bio->bi_opf & REQ_PREFLUSH)
2413 bio_endio(bio);
2414 else
2415 dm_submit_bio_remap(bio, NULL);
2416 }
2417}
2418
2419static void do_worker(struct work_struct *ws)
2420{
2421 struct pool *pool = container_of(ws, struct pool, worker);
2422
2423 throttle_work_start(&pool->throttle);
2424 dm_pool_issue_prefetches(pool->pmd);
2425 throttle_work_update(&pool->throttle);
2426 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
2427 throttle_work_update(&pool->throttle);
2428 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
2429 throttle_work_update(&pool->throttle);
2430 process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2);
2431 throttle_work_update(&pool->throttle);
2432 process_deferred_bios(pool);
2433 throttle_work_complete(&pool->throttle);
2434}
2435
2436/*
2437 * We want to commit periodically so that not too much
2438 * unwritten data builds up.
2439 */
2440static void do_waker(struct work_struct *ws)
2441{
2442 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
2443
2444 wake_worker(pool);
2445 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
2446}
2447
2448/*
2449 * We're holding onto IO to allow userland time to react. After the
2450 * timeout either the pool will have been resized (and thus back in
2451 * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space.
2452 */
2453static void do_no_space_timeout(struct work_struct *ws)
2454{
2455 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
2456 no_space_timeout);
2457
2458 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
2459 pool->pf.error_if_no_space = true;
2460 notify_of_pool_mode_change(pool);
2461 error_retry_list_with_code(pool, BLK_STS_NOSPC);
2462 }
2463}
2464
2465/*----------------------------------------------------------------*/
2466
2467struct pool_work {
2468 struct work_struct worker;
2469 struct completion complete;
2470};
2471
2472static struct pool_work *to_pool_work(struct work_struct *ws)
2473{
2474 return container_of(ws, struct pool_work, worker);
2475}
2476
2477static void pool_work_complete(struct pool_work *pw)
2478{
2479 complete(&pw->complete);
2480}
2481
2482static void pool_work_wait(struct pool_work *pw, struct pool *pool,
2483 void (*fn)(struct work_struct *))
2484{
2485 INIT_WORK_ONSTACK(&pw->worker, fn);
2486 init_completion(&pw->complete);
2487 queue_work(pool->wq, &pw->worker);
2488 wait_for_completion(&pw->complete);
2489}
2490
2491/*----------------------------------------------------------------*/
2492
2493struct noflush_work {
2494 struct pool_work pw;
2495 struct thin_c *tc;
2496};
2497
2498static struct noflush_work *to_noflush(struct work_struct *ws)
2499{
2500 return container_of(to_pool_work(ws), struct noflush_work, pw);
2501}
2502
2503static void do_noflush_start(struct work_struct *ws)
2504{
2505 struct noflush_work *w = to_noflush(ws);
2506
2507 w->tc->requeue_mode = true;
2508 requeue_io(w->tc);
2509 pool_work_complete(&w->pw);
2510}
2511
2512static void do_noflush_stop(struct work_struct *ws)
2513{
2514 struct noflush_work *w = to_noflush(ws);
2515
2516 w->tc->requeue_mode = false;
2517 pool_work_complete(&w->pw);
2518}
2519
2520static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
2521{
2522 struct noflush_work w;
2523
2524 w.tc = tc;
2525 pool_work_wait(&w.pw, tc->pool, fn);
2526}
2527
2528/*----------------------------------------------------------------*/
2529
2530static void set_discard_callbacks(struct pool *pool)
2531{
2532 struct pool_c *pt = pool->ti->private;
2533
2534 if (pt->adjusted_pf.discard_passdown) {
2535 pool->process_discard_cell = process_discard_cell_passdown;
2536 pool->process_prepared_discard = process_prepared_discard_passdown_pt1;
2537 pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2;
2538 } else {
2539 pool->process_discard_cell = process_discard_cell_no_passdown;
2540 pool->process_prepared_discard = process_prepared_discard_no_passdown;
2541 }
2542}
2543
2544static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
2545{
2546 struct pool_c *pt = pool->ti->private;
2547 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
2548 enum pool_mode old_mode = get_pool_mode(pool);
2549 unsigned long no_space_timeout = READ_ONCE(no_space_timeout_secs) * HZ;
2550
2551 /*
2552 * Never allow the pool to transition to PM_WRITE mode if user
2553 * intervention is required to verify metadata and data consistency.
2554 */
2555 if (new_mode == PM_WRITE && needs_check) {
2556 DMERR("%s: unable to switch pool to write mode until repaired.",
2557 dm_device_name(pool->pool_md));
2558 if (old_mode != new_mode)
2559 new_mode = old_mode;
2560 else
2561 new_mode = PM_READ_ONLY;
2562 }
2563 /*
2564 * If we were in PM_FAIL mode, rollback of metadata failed. We're
2565 * not going to recover without a thin_repair. So we never let the
2566 * pool move out of the old mode.
2567 */
2568 if (old_mode == PM_FAIL)
2569 new_mode = old_mode;
2570
2571 switch (new_mode) {
2572 case PM_FAIL:
2573 dm_pool_metadata_read_only(pool->pmd);
2574 pool->process_bio = process_bio_fail;
2575 pool->process_discard = process_bio_fail;
2576 pool->process_cell = process_cell_fail;
2577 pool->process_discard_cell = process_cell_fail;
2578 pool->process_prepared_mapping = process_prepared_mapping_fail;
2579 pool->process_prepared_discard = process_prepared_discard_fail;
2580
2581 error_retry_list(pool);
2582 break;
2583
2584 case PM_OUT_OF_METADATA_SPACE:
2585 case PM_READ_ONLY:
2586 dm_pool_metadata_read_only(pool->pmd);
2587 pool->process_bio = process_bio_read_only;
2588 pool->process_discard = process_bio_success;
2589 pool->process_cell = process_cell_read_only;
2590 pool->process_discard_cell = process_cell_success;
2591 pool->process_prepared_mapping = process_prepared_mapping_fail;
2592 pool->process_prepared_discard = process_prepared_discard_success;
2593
2594 error_retry_list(pool);
2595 break;
2596
2597 case PM_OUT_OF_DATA_SPACE:
2598 /*
2599 * Ideally we'd never hit this state; the low water mark
2600 * would trigger userland to extend the pool before we
2601 * completely run out of data space. However, many small
2602 * IOs to unprovisioned space can consume data space at an
2603 * alarming rate. Adjust your low water mark if you're
2604 * frequently seeing this mode.
2605 */
2606 pool->out_of_data_space = true;
2607 pool->process_bio = process_bio_read_only;
2608 pool->process_discard = process_discard_bio;
2609 pool->process_cell = process_cell_read_only;
2610 pool->process_prepared_mapping = process_prepared_mapping;
2611 set_discard_callbacks(pool);
2612
2613 if (!pool->pf.error_if_no_space && no_space_timeout)
2614 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
2615 break;
2616
2617 case PM_WRITE:
2618 if (old_mode == PM_OUT_OF_DATA_SPACE)
2619 cancel_delayed_work_sync(&pool->no_space_timeout);
2620 pool->out_of_data_space = false;
2621 pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
2622 dm_pool_metadata_read_write(pool->pmd);
2623 pool->process_bio = process_bio;
2624 pool->process_discard = process_discard_bio;
2625 pool->process_cell = process_cell;
2626 pool->process_prepared_mapping = process_prepared_mapping;
2627 set_discard_callbacks(pool);
2628 break;
2629 }
2630
2631 pool->pf.mode = new_mode;
2632 /*
2633 * The pool mode may have changed, sync it so bind_control_target()
2634 * doesn't cause an unexpected mode transition on resume.
2635 */
2636 pt->adjusted_pf.mode = new_mode;
2637
2638 if (old_mode != new_mode)
2639 notify_of_pool_mode_change(pool);
2640}
2641
2642static void abort_transaction(struct pool *pool)
2643{
2644 const char *dev_name = dm_device_name(pool->pool_md);
2645
2646 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
2647 if (dm_pool_abort_metadata(pool->pmd)) {
2648 DMERR("%s: failed to abort metadata transaction", dev_name);
2649 set_pool_mode(pool, PM_FAIL);
2650 }
2651
2652 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
2653 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
2654 set_pool_mode(pool, PM_FAIL);
2655 }
2656}
2657
2658static void metadata_operation_failed(struct pool *pool, const char *op, int r)
2659{
2660 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
2661 dm_device_name(pool->pool_md), op, r);
2662
2663 abort_transaction(pool);
2664 set_pool_mode(pool, PM_READ_ONLY);
2665}
2666
2667/*----------------------------------------------------------------*/
2668
2669/*
2670 * Mapping functions.
2671 */
2672
2673/*
2674 * Called only while mapping a thin bio to hand it over to the workqueue.
2675 */
2676static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
2677{
2678 struct pool *pool = tc->pool;
2679
2680 spin_lock_irq(&tc->lock);
2681 bio_list_add(&tc->deferred_bio_list, bio);
2682 spin_unlock_irq(&tc->lock);
2683
2684 wake_worker(pool);
2685}
2686
2687static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
2688{
2689 struct pool *pool = tc->pool;
2690
2691 throttle_lock(&pool->throttle);
2692 thin_defer_bio(tc, bio);
2693 throttle_unlock(&pool->throttle);
2694}
2695
2696static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
2697{
2698 struct pool *pool = tc->pool;
2699
2700 throttle_lock(&pool->throttle);
2701 spin_lock_irq(&tc->lock);
2702 list_add_tail(&cell->user_list, &tc->deferred_cells);
2703 spin_unlock_irq(&tc->lock);
2704 throttle_unlock(&pool->throttle);
2705
2706 wake_worker(pool);
2707}
2708
2709static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
2710{
2711 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
2712
2713 h->tc = tc;
2714 h->shared_read_entry = NULL;
2715 h->all_io_entry = NULL;
2716 h->overwrite_mapping = NULL;
2717 h->cell = NULL;
2718}
2719
2720/*
2721 * Non-blocking function called from the thin target's map function.
2722 */
2723static int thin_bio_map(struct dm_target *ti, struct bio *bio)
2724{
2725 int r;
2726 struct thin_c *tc = ti->private;
2727 dm_block_t block = get_bio_block(tc, bio);
2728 struct dm_thin_device *td = tc->td;
2729 struct dm_thin_lookup_result result;
2730 struct dm_bio_prison_cell *virt_cell, *data_cell;
2731 struct dm_cell_key key;
2732
2733 thin_hook_bio(tc, bio);
2734
2735 if (tc->requeue_mode) {
2736 bio->bi_status = BLK_STS_DM_REQUEUE;
2737 bio_endio(bio);
2738 return DM_MAPIO_SUBMITTED;
2739 }
2740
2741 if (get_pool_mode(tc->pool) == PM_FAIL) {
2742 bio_io_error(bio);
2743 return DM_MAPIO_SUBMITTED;
2744 }
2745
2746 if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) {
2747 thin_defer_bio_with_throttle(tc, bio);
2748 return DM_MAPIO_SUBMITTED;
2749 }
2750
2751 /*
2752 * We must hold the virtual cell before doing the lookup, otherwise
2753 * there's a race with discard.
2754 */
2755 build_virtual_key(tc->td, block, &key);
2756 if (bio_detain(tc->pool, &key, bio, &virt_cell))
2757 return DM_MAPIO_SUBMITTED;
2758
2759 r = dm_thin_find_block(td, block, 0, &result);
2760
2761 /*
2762 * Note that we defer readahead too.
2763 */
2764 switch (r) {
2765 case 0:
2766 if (unlikely(result.shared)) {
2767 /*
2768 * We have a race condition here between the
2769 * result.shared value returned by the lookup and
2770 * snapshot creation, which may cause new
2771 * sharing.
2772 *
2773 * To avoid this always quiesce the origin before
2774 * taking the snap. You want to do this anyway to
2775 * ensure a consistent application view
2776 * (i.e. lockfs).
2777 *
2778 * More distant ancestors are irrelevant. The
2779 * shared flag will be set in their case.
2780 */
2781 thin_defer_cell(tc, virt_cell);
2782 return DM_MAPIO_SUBMITTED;
2783 }
2784
2785 build_data_key(tc->td, result.block, &key);
2786 if (bio_detain(tc->pool, &key, bio, &data_cell)) {
2787 cell_defer_no_holder(tc, virt_cell);
2788 return DM_MAPIO_SUBMITTED;
2789 }
2790
2791 inc_all_io_entry(tc->pool, bio);
2792 cell_defer_no_holder(tc, data_cell);
2793 cell_defer_no_holder(tc, virt_cell);
2794
2795 remap(tc, bio, result.block);
2796 return DM_MAPIO_REMAPPED;
2797
2798 case -ENODATA:
2799 case -EWOULDBLOCK:
2800 thin_defer_cell(tc, virt_cell);
2801 return DM_MAPIO_SUBMITTED;
2802
2803 default:
2804 /*
2805 * Must always call bio_io_error on failure.
2806 * dm_thin_find_block can fail with -EINVAL if the
2807 * pool is switched to fail-io mode.
2808 */
2809 bio_io_error(bio);
2810 cell_defer_no_holder(tc, virt_cell);
2811 return DM_MAPIO_SUBMITTED;
2812 }
2813}
2814
2815static void requeue_bios(struct pool *pool)
2816{
2817 struct thin_c *tc;
2818
2819 rcu_read_lock();
2820 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
2821 spin_lock_irq(&tc->lock);
2822 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
2823 bio_list_init(&tc->retry_on_resume_list);
2824 spin_unlock_irq(&tc->lock);
2825 }
2826 rcu_read_unlock();
2827}
2828
2829/*
2830 *--------------------------------------------------------------
2831 * Binding of control targets to a pool object
2832 *--------------------------------------------------------------
2833 */
2834static bool is_factor(sector_t block_size, uint32_t n)
2835{
2836 return !sector_div(block_size, n);
2837}
2838
2839/*
2840 * If discard_passdown was enabled verify that the data device
2841 * supports discards. Disable discard_passdown if not.
2842 */
2843static void disable_discard_passdown_if_not_supported(struct pool_c *pt)
2844{
2845 struct pool *pool = pt->pool;
2846 struct block_device *data_bdev = pt->data_dev->bdev;
2847 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
2848 const char *reason = NULL;
2849
2850 if (!pt->adjusted_pf.discard_passdown)
2851 return;
2852
2853 if (!bdev_max_discard_sectors(pt->data_dev->bdev))
2854 reason = "discard unsupported";
2855
2856 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
2857 reason = "max discard sectors smaller than a block";
2858
2859 if (reason) {
2860 DMWARN("Data device (%pg) %s: Disabling discard passdown.", data_bdev, reason);
2861 pt->adjusted_pf.discard_passdown = false;
2862 }
2863}
2864
2865static int bind_control_target(struct pool *pool, struct dm_target *ti)
2866{
2867 struct pool_c *pt = ti->private;
2868
2869 /*
2870 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2871 */
2872 enum pool_mode old_mode = get_pool_mode(pool);
2873 enum pool_mode new_mode = pt->adjusted_pf.mode;
2874
2875 /*
2876 * Don't change the pool's mode until set_pool_mode() below.
2877 * Otherwise the pool's process_* function pointers may
2878 * not match the desired pool mode.
2879 */
2880 pt->adjusted_pf.mode = old_mode;
2881
2882 pool->ti = ti;
2883 pool->pf = pt->adjusted_pf;
2884 pool->low_water_blocks = pt->low_water_blocks;
2885
2886 set_pool_mode(pool, new_mode);
2887
2888 return 0;
2889}
2890
2891static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2892{
2893 if (pool->ti == ti)
2894 pool->ti = NULL;
2895}
2896
2897/*
2898 *--------------------------------------------------------------
2899 * Pool creation
2900 *--------------------------------------------------------------
2901 */
2902/* Initialize pool features. */
2903static void pool_features_init(struct pool_features *pf)
2904{
2905 pf->mode = PM_WRITE;
2906 pf->zero_new_blocks = true;
2907 pf->discard_enabled = true;
2908 pf->discard_passdown = true;
2909 pf->error_if_no_space = false;
2910}
2911
2912static void __pool_destroy(struct pool *pool)
2913{
2914 __pool_table_remove(pool);
2915
2916 vfree(pool->cell_sort_array);
2917 if (dm_pool_metadata_close(pool->pmd) < 0)
2918 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2919
2920 dm_bio_prison_destroy(pool->prison);
2921 dm_kcopyd_client_destroy(pool->copier);
2922
2923 cancel_delayed_work_sync(&pool->waker);
2924 cancel_delayed_work_sync(&pool->no_space_timeout);
2925 if (pool->wq)
2926 destroy_workqueue(pool->wq);
2927
2928 if (pool->next_mapping)
2929 mempool_free(pool->next_mapping, &pool->mapping_pool);
2930 mempool_exit(&pool->mapping_pool);
2931 dm_deferred_set_destroy(pool->shared_read_ds);
2932 dm_deferred_set_destroy(pool->all_io_ds);
2933 kfree(pool);
2934}
2935
2936static struct kmem_cache *_new_mapping_cache;
2937
2938static struct pool *pool_create(struct mapped_device *pool_md,
2939 struct block_device *metadata_dev,
2940 struct block_device *data_dev,
2941 unsigned long block_size,
2942 int read_only, char **error)
2943{
2944 int r;
2945 void *err_p;
2946 struct pool *pool;
2947 struct dm_pool_metadata *pmd;
2948 bool format_device = read_only ? false : true;
2949
2950 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2951 if (IS_ERR(pmd)) {
2952 *error = "Error creating metadata object";
2953 return (struct pool *)pmd;
2954 }
2955
2956 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
2957 if (!pool) {
2958 *error = "Error allocating memory for pool";
2959 err_p = ERR_PTR(-ENOMEM);
2960 goto bad_pool;
2961 }
2962
2963 pool->pmd = pmd;
2964 pool->sectors_per_block = block_size;
2965 if (block_size & (block_size - 1))
2966 pool->sectors_per_block_shift = -1;
2967 else
2968 pool->sectors_per_block_shift = __ffs(block_size);
2969 pool->low_water_blocks = 0;
2970 pool_features_init(&pool->pf);
2971 pool->prison = dm_bio_prison_create();
2972 if (!pool->prison) {
2973 *error = "Error creating pool's bio prison";
2974 err_p = ERR_PTR(-ENOMEM);
2975 goto bad_prison;
2976 }
2977
2978 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2979 if (IS_ERR(pool->copier)) {
2980 r = PTR_ERR(pool->copier);
2981 *error = "Error creating pool's kcopyd client";
2982 err_p = ERR_PTR(r);
2983 goto bad_kcopyd_client;
2984 }
2985
2986 /*
2987 * Create singlethreaded workqueue that will service all devices
2988 * that use this metadata.
2989 */
2990 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2991 if (!pool->wq) {
2992 *error = "Error creating pool's workqueue";
2993 err_p = ERR_PTR(-ENOMEM);
2994 goto bad_wq;
2995 }
2996
2997 throttle_init(&pool->throttle);
2998 INIT_WORK(&pool->worker, do_worker);
2999 INIT_DELAYED_WORK(&pool->waker, do_waker);
3000 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
3001 spin_lock_init(&pool->lock);
3002 bio_list_init(&pool->deferred_flush_bios);
3003 bio_list_init(&pool->deferred_flush_completions);
3004 INIT_LIST_HEAD(&pool->prepared_mappings);
3005 INIT_LIST_HEAD(&pool->prepared_discards);
3006 INIT_LIST_HEAD(&pool->prepared_discards_pt2);
3007 INIT_LIST_HEAD(&pool->active_thins);
3008 pool->low_water_triggered = false;
3009 pool->suspended = true;
3010 pool->out_of_data_space = false;
3011
3012 pool->shared_read_ds = dm_deferred_set_create();
3013 if (!pool->shared_read_ds) {
3014 *error = "Error creating pool's shared read deferred set";
3015 err_p = ERR_PTR(-ENOMEM);
3016 goto bad_shared_read_ds;
3017 }
3018
3019 pool->all_io_ds = dm_deferred_set_create();
3020 if (!pool->all_io_ds) {
3021 *error = "Error creating pool's all io deferred set";
3022 err_p = ERR_PTR(-ENOMEM);
3023 goto bad_all_io_ds;
3024 }
3025
3026 pool->next_mapping = NULL;
3027 r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE,
3028 _new_mapping_cache);
3029 if (r) {
3030 *error = "Error creating pool's mapping mempool";
3031 err_p = ERR_PTR(r);
3032 goto bad_mapping_pool;
3033 }
3034
3035 pool->cell_sort_array =
3036 vmalloc(array_size(CELL_SORT_ARRAY_SIZE,
3037 sizeof(*pool->cell_sort_array)));
3038 if (!pool->cell_sort_array) {
3039 *error = "Error allocating cell sort array";
3040 err_p = ERR_PTR(-ENOMEM);
3041 goto bad_sort_array;
3042 }
3043
3044 pool->ref_count = 1;
3045 pool->last_commit_jiffies = jiffies;
3046 pool->pool_md = pool_md;
3047 pool->md_dev = metadata_dev;
3048 pool->data_dev = data_dev;
3049 __pool_table_insert(pool);
3050
3051 return pool;
3052
3053bad_sort_array:
3054 mempool_exit(&pool->mapping_pool);
3055bad_mapping_pool:
3056 dm_deferred_set_destroy(pool->all_io_ds);
3057bad_all_io_ds:
3058 dm_deferred_set_destroy(pool->shared_read_ds);
3059bad_shared_read_ds:
3060 destroy_workqueue(pool->wq);
3061bad_wq:
3062 dm_kcopyd_client_destroy(pool->copier);
3063bad_kcopyd_client:
3064 dm_bio_prison_destroy(pool->prison);
3065bad_prison:
3066 kfree(pool);
3067bad_pool:
3068 if (dm_pool_metadata_close(pmd))
3069 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
3070
3071 return err_p;
3072}
3073
3074static void __pool_inc(struct pool *pool)
3075{
3076 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3077 pool->ref_count++;
3078}
3079
3080static void __pool_dec(struct pool *pool)
3081{
3082 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
3083 BUG_ON(!pool->ref_count);
3084 if (!--pool->ref_count)
3085 __pool_destroy(pool);
3086}
3087
3088static struct pool *__pool_find(struct mapped_device *pool_md,
3089 struct block_device *metadata_dev,
3090 struct block_device *data_dev,
3091 unsigned long block_size, int read_only,
3092 char **error, int *created)
3093{
3094 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
3095
3096 if (pool) {
3097 if (pool->pool_md != pool_md) {
3098 *error = "metadata device already in use by a pool";
3099 return ERR_PTR(-EBUSY);
3100 }
3101 if (pool->data_dev != data_dev) {
3102 *error = "data device already in use by a pool";
3103 return ERR_PTR(-EBUSY);
3104 }
3105 __pool_inc(pool);
3106
3107 } else {
3108 pool = __pool_table_lookup(pool_md);
3109 if (pool) {
3110 if (pool->md_dev != metadata_dev || pool->data_dev != data_dev) {
3111 *error = "different pool cannot replace a pool";
3112 return ERR_PTR(-EINVAL);
3113 }
3114 __pool_inc(pool);
3115
3116 } else {
3117 pool = pool_create(pool_md, metadata_dev, data_dev, block_size, read_only, error);
3118 *created = 1;
3119 }
3120 }
3121
3122 return pool;
3123}
3124
3125/*
3126 *--------------------------------------------------------------
3127 * Pool target methods
3128 *--------------------------------------------------------------
3129 */
3130static void pool_dtr(struct dm_target *ti)
3131{
3132 struct pool_c *pt = ti->private;
3133
3134 mutex_lock(&dm_thin_pool_table.mutex);
3135
3136 unbind_control_target(pt->pool, ti);
3137 __pool_dec(pt->pool);
3138 dm_put_device(ti, pt->metadata_dev);
3139 dm_put_device(ti, pt->data_dev);
3140 kfree(pt);
3141
3142 mutex_unlock(&dm_thin_pool_table.mutex);
3143}
3144
3145static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
3146 struct dm_target *ti)
3147{
3148 int r;
3149 unsigned int argc;
3150 const char *arg_name;
3151
3152 static const struct dm_arg _args[] = {
3153 {0, 4, "Invalid number of pool feature arguments"},
3154 };
3155
3156 /*
3157 * No feature arguments supplied.
3158 */
3159 if (!as->argc)
3160 return 0;
3161
3162 r = dm_read_arg_group(_args, as, &argc, &ti->error);
3163 if (r)
3164 return -EINVAL;
3165
3166 while (argc && !r) {
3167 arg_name = dm_shift_arg(as);
3168 argc--;
3169
3170 if (!strcasecmp(arg_name, "skip_block_zeroing"))
3171 pf->zero_new_blocks = false;
3172
3173 else if (!strcasecmp(arg_name, "ignore_discard"))
3174 pf->discard_enabled = false;
3175
3176 else if (!strcasecmp(arg_name, "no_discard_passdown"))
3177 pf->discard_passdown = false;
3178
3179 else if (!strcasecmp(arg_name, "read_only"))
3180 pf->mode = PM_READ_ONLY;
3181
3182 else if (!strcasecmp(arg_name, "error_if_no_space"))
3183 pf->error_if_no_space = true;
3184
3185 else {
3186 ti->error = "Unrecognised pool feature requested";
3187 r = -EINVAL;
3188 break;
3189 }
3190 }
3191
3192 return r;
3193}
3194
3195static void metadata_low_callback(void *context)
3196{
3197 struct pool *pool = context;
3198
3199 DMWARN("%s: reached low water mark for metadata device: sending event.",
3200 dm_device_name(pool->pool_md));
3201
3202 dm_table_event(pool->ti->table);
3203}
3204
3205/*
3206 * We need to flush the data device **before** committing the metadata.
3207 *
3208 * This ensures that the data blocks of any newly inserted mappings are
3209 * properly written to non-volatile storage and won't be lost in case of a
3210 * crash.
3211 *
3212 * Failure to do so can result in data corruption in the case of internal or
3213 * external snapshots and in the case of newly provisioned blocks, when block
3214 * zeroing is enabled.
3215 */
3216static int metadata_pre_commit_callback(void *context)
3217{
3218 struct pool *pool = context;
3219
3220 return blkdev_issue_flush(pool->data_dev);
3221}
3222
3223static sector_t get_dev_size(struct block_device *bdev)
3224{
3225 return bdev_nr_sectors(bdev);
3226}
3227
3228static void warn_if_metadata_device_too_big(struct block_device *bdev)
3229{
3230 sector_t metadata_dev_size = get_dev_size(bdev);
3231
3232 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
3233 DMWARN("Metadata device %pg is larger than %u sectors: excess space will not be used.",
3234 bdev, THIN_METADATA_MAX_SECTORS);
3235}
3236
3237static sector_t get_metadata_dev_size(struct block_device *bdev)
3238{
3239 sector_t metadata_dev_size = get_dev_size(bdev);
3240
3241 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
3242 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
3243
3244 return metadata_dev_size;
3245}
3246
3247static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
3248{
3249 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
3250
3251 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
3252
3253 return metadata_dev_size;
3254}
3255
3256/*
3257 * When a metadata threshold is crossed a dm event is triggered, and
3258 * userland should respond by growing the metadata device. We could let
3259 * userland set the threshold, like we do with the data threshold, but I'm
3260 * not sure they know enough to do this well.
3261 */
3262static dm_block_t calc_metadata_threshold(struct pool_c *pt)
3263{
3264 /*
3265 * 4M is ample for all ops with the possible exception of thin
3266 * device deletion which is harmless if it fails (just retry the
3267 * delete after you've grown the device).
3268 */
3269 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
3270
3271 return min((dm_block_t)1024ULL /* 4M */, quarter);
3272}
3273
3274/*
3275 * thin-pool <metadata dev> <data dev>
3276 * <data block size (sectors)>
3277 * <low water mark (blocks)>
3278 * [<#feature args> [<arg>]*]
3279 *
3280 * Optional feature arguments are:
3281 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
3282 * ignore_discard: disable discard
3283 * no_discard_passdown: don't pass discards down to the data device
3284 * read_only: Don't allow any changes to be made to the pool metadata.
3285 * error_if_no_space: error IOs, instead of queueing, if no space.
3286 */
3287static int pool_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3288{
3289 int r, pool_created = 0;
3290 struct pool_c *pt;
3291 struct pool *pool;
3292 struct pool_features pf;
3293 struct dm_arg_set as;
3294 struct dm_dev *data_dev;
3295 unsigned long block_size;
3296 dm_block_t low_water_blocks;
3297 struct dm_dev *metadata_dev;
3298 blk_mode_t metadata_mode;
3299
3300 /*
3301 * FIXME Remove validation from scope of lock.
3302 */
3303 mutex_lock(&dm_thin_pool_table.mutex);
3304
3305 if (argc < 4) {
3306 ti->error = "Invalid argument count";
3307 r = -EINVAL;
3308 goto out_unlock;
3309 }
3310
3311 as.argc = argc;
3312 as.argv = argv;
3313
3314 /* make sure metadata and data are different devices */
3315 if (!strcmp(argv[0], argv[1])) {
3316 ti->error = "Error setting metadata or data device";
3317 r = -EINVAL;
3318 goto out_unlock;
3319 }
3320
3321 /*
3322 * Set default pool features.
3323 */
3324 pool_features_init(&pf);
3325
3326 dm_consume_args(&as, 4);
3327 r = parse_pool_features(&as, &pf, ti);
3328 if (r)
3329 goto out_unlock;
3330
3331 metadata_mode = BLK_OPEN_READ |
3332 ((pf.mode == PM_READ_ONLY) ? 0 : BLK_OPEN_WRITE);
3333 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
3334 if (r) {
3335 ti->error = "Error opening metadata block device";
3336 goto out_unlock;
3337 }
3338 warn_if_metadata_device_too_big(metadata_dev->bdev);
3339
3340 r = dm_get_device(ti, argv[1], BLK_OPEN_READ | BLK_OPEN_WRITE, &data_dev);
3341 if (r) {
3342 ti->error = "Error getting data device";
3343 goto out_metadata;
3344 }
3345
3346 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
3347 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
3348 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
3349 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
3350 ti->error = "Invalid block size";
3351 r = -EINVAL;
3352 goto out;
3353 }
3354
3355 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
3356 ti->error = "Invalid low water mark";
3357 r = -EINVAL;
3358 goto out;
3359 }
3360
3361 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
3362 if (!pt) {
3363 r = -ENOMEM;
3364 goto out;
3365 }
3366
3367 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, data_dev->bdev,
3368 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
3369 if (IS_ERR(pool)) {
3370 r = PTR_ERR(pool);
3371 goto out_free_pt;
3372 }
3373
3374 /*
3375 * 'pool_created' reflects whether this is the first table load.
3376 * Top level discard support is not allowed to be changed after
3377 * initial load. This would require a pool reload to trigger thin
3378 * device changes.
3379 */
3380 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
3381 ti->error = "Discard support cannot be disabled once enabled";
3382 r = -EINVAL;
3383 goto out_flags_changed;
3384 }
3385
3386 pt->pool = pool;
3387 pt->ti = ti;
3388 pt->metadata_dev = metadata_dev;
3389 pt->data_dev = data_dev;
3390 pt->low_water_blocks = low_water_blocks;
3391 pt->adjusted_pf = pt->requested_pf = pf;
3392 ti->num_flush_bios = 1;
3393 ti->limit_swap_bios = true;
3394
3395 /*
3396 * Only need to enable discards if the pool should pass
3397 * them down to the data device. The thin device's discard
3398 * processing will cause mappings to be removed from the btree.
3399 */
3400 if (pf.discard_enabled && pf.discard_passdown) {
3401 ti->num_discard_bios = 1;
3402 /*
3403 * Setting 'discards_supported' circumvents the normal
3404 * stacking of discard limits (this keeps the pool and
3405 * thin devices' discard limits consistent).
3406 */
3407 ti->discards_supported = true;
3408 ti->max_discard_granularity = true;
3409 }
3410 ti->private = pt;
3411
3412 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
3413 calc_metadata_threshold(pt),
3414 metadata_low_callback,
3415 pool);
3416 if (r) {
3417 ti->error = "Error registering metadata threshold";
3418 goto out_flags_changed;
3419 }
3420
3421 dm_pool_register_pre_commit_callback(pool->pmd,
3422 metadata_pre_commit_callback, pool);
3423
3424 mutex_unlock(&dm_thin_pool_table.mutex);
3425
3426 return 0;
3427
3428out_flags_changed:
3429 __pool_dec(pool);
3430out_free_pt:
3431 kfree(pt);
3432out:
3433 dm_put_device(ti, data_dev);
3434out_metadata:
3435 dm_put_device(ti, metadata_dev);
3436out_unlock:
3437 mutex_unlock(&dm_thin_pool_table.mutex);
3438
3439 return r;
3440}
3441
3442static int pool_map(struct dm_target *ti, struct bio *bio)
3443{
3444 struct pool_c *pt = ti->private;
3445 struct pool *pool = pt->pool;
3446
3447 /*
3448 * As this is a singleton target, ti->begin is always zero.
3449 */
3450 spin_lock_irq(&pool->lock);
3451 bio_set_dev(bio, pt->data_dev->bdev);
3452 spin_unlock_irq(&pool->lock);
3453
3454 return DM_MAPIO_REMAPPED;
3455}
3456
3457static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
3458{
3459 int r;
3460 struct pool_c *pt = ti->private;
3461 struct pool *pool = pt->pool;
3462 sector_t data_size = ti->len;
3463 dm_block_t sb_data_size;
3464
3465 *need_commit = false;
3466
3467 (void) sector_div(data_size, pool->sectors_per_block);
3468
3469 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
3470 if (r) {
3471 DMERR("%s: failed to retrieve data device size",
3472 dm_device_name(pool->pool_md));
3473 return r;
3474 }
3475
3476 if (data_size < sb_data_size) {
3477 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
3478 dm_device_name(pool->pool_md),
3479 (unsigned long long)data_size, sb_data_size);
3480 return -EINVAL;
3481
3482 } else if (data_size > sb_data_size) {
3483 if (dm_pool_metadata_needs_check(pool->pmd)) {
3484 DMERR("%s: unable to grow the data device until repaired.",
3485 dm_device_name(pool->pool_md));
3486 return 0;
3487 }
3488
3489 if (sb_data_size)
3490 DMINFO("%s: growing the data device from %llu to %llu blocks",
3491 dm_device_name(pool->pool_md),
3492 sb_data_size, (unsigned long long)data_size);
3493 r = dm_pool_resize_data_dev(pool->pmd, data_size);
3494 if (r) {
3495 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
3496 return r;
3497 }
3498
3499 *need_commit = true;
3500 }
3501
3502 return 0;
3503}
3504
3505static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
3506{
3507 int r;
3508 struct pool_c *pt = ti->private;
3509 struct pool *pool = pt->pool;
3510 dm_block_t metadata_dev_size, sb_metadata_dev_size;
3511
3512 *need_commit = false;
3513
3514 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
3515
3516 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
3517 if (r) {
3518 DMERR("%s: failed to retrieve metadata device size",
3519 dm_device_name(pool->pool_md));
3520 return r;
3521 }
3522
3523 if (metadata_dev_size < sb_metadata_dev_size) {
3524 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
3525 dm_device_name(pool->pool_md),
3526 metadata_dev_size, sb_metadata_dev_size);
3527 return -EINVAL;
3528
3529 } else if (metadata_dev_size > sb_metadata_dev_size) {
3530 if (dm_pool_metadata_needs_check(pool->pmd)) {
3531 DMERR("%s: unable to grow the metadata device until repaired.",
3532 dm_device_name(pool->pool_md));
3533 return 0;
3534 }
3535
3536 warn_if_metadata_device_too_big(pool->md_dev);
3537 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
3538 dm_device_name(pool->pool_md),
3539 sb_metadata_dev_size, metadata_dev_size);
3540
3541 if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE)
3542 set_pool_mode(pool, PM_WRITE);
3543
3544 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
3545 if (r) {
3546 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
3547 return r;
3548 }
3549
3550 *need_commit = true;
3551 }
3552
3553 return 0;
3554}
3555
3556/*
3557 * Retrieves the number of blocks of the data device from
3558 * the superblock and compares it to the actual device size,
3559 * thus resizing the data device in case it has grown.
3560 *
3561 * This both copes with opening preallocated data devices in the ctr
3562 * being followed by a resume
3563 * -and-
3564 * calling the resume method individually after userspace has
3565 * grown the data device in reaction to a table event.
3566 */
3567static int pool_preresume(struct dm_target *ti)
3568{
3569 int r;
3570 bool need_commit1, need_commit2;
3571 struct pool_c *pt = ti->private;
3572 struct pool *pool = pt->pool;
3573
3574 /*
3575 * Take control of the pool object.
3576 */
3577 r = bind_control_target(pool, ti);
3578 if (r)
3579 goto out;
3580
3581 r = maybe_resize_data_dev(ti, &need_commit1);
3582 if (r)
3583 goto out;
3584
3585 r = maybe_resize_metadata_dev(ti, &need_commit2);
3586 if (r)
3587 goto out;
3588
3589 if (need_commit1 || need_commit2)
3590 (void) commit(pool);
3591out:
3592 /*
3593 * When a thin-pool is PM_FAIL, it cannot be rebuilt if
3594 * bio is in deferred list. Therefore need to return 0
3595 * to allow pool_resume() to flush IO.
3596 */
3597 if (r && get_pool_mode(pool) == PM_FAIL)
3598 r = 0;
3599
3600 return r;
3601}
3602
3603static void pool_suspend_active_thins(struct pool *pool)
3604{
3605 struct thin_c *tc;
3606
3607 /* Suspend all active thin devices */
3608 tc = get_first_thin(pool);
3609 while (tc) {
3610 dm_internal_suspend_noflush(tc->thin_md);
3611 tc = get_next_thin(pool, tc);
3612 }
3613}
3614
3615static void pool_resume_active_thins(struct pool *pool)
3616{
3617 struct thin_c *tc;
3618
3619 /* Resume all active thin devices */
3620 tc = get_first_thin(pool);
3621 while (tc) {
3622 dm_internal_resume(tc->thin_md);
3623 tc = get_next_thin(pool, tc);
3624 }
3625}
3626
3627static void pool_resume(struct dm_target *ti)
3628{
3629 struct pool_c *pt = ti->private;
3630 struct pool *pool = pt->pool;
3631
3632 /*
3633 * Must requeue active_thins' bios and then resume
3634 * active_thins _before_ clearing 'suspend' flag.
3635 */
3636 requeue_bios(pool);
3637 pool_resume_active_thins(pool);
3638
3639 spin_lock_irq(&pool->lock);
3640 pool->low_water_triggered = false;
3641 pool->suspended = false;
3642 spin_unlock_irq(&pool->lock);
3643
3644 do_waker(&pool->waker.work);
3645}
3646
3647static void pool_presuspend(struct dm_target *ti)
3648{
3649 struct pool_c *pt = ti->private;
3650 struct pool *pool = pt->pool;
3651
3652 spin_lock_irq(&pool->lock);
3653 pool->suspended = true;
3654 spin_unlock_irq(&pool->lock);
3655
3656 pool_suspend_active_thins(pool);
3657}
3658
3659static void pool_presuspend_undo(struct dm_target *ti)
3660{
3661 struct pool_c *pt = ti->private;
3662 struct pool *pool = pt->pool;
3663
3664 pool_resume_active_thins(pool);
3665
3666 spin_lock_irq(&pool->lock);
3667 pool->suspended = false;
3668 spin_unlock_irq(&pool->lock);
3669}
3670
3671static void pool_postsuspend(struct dm_target *ti)
3672{
3673 struct pool_c *pt = ti->private;
3674 struct pool *pool = pt->pool;
3675
3676 cancel_delayed_work_sync(&pool->waker);
3677 cancel_delayed_work_sync(&pool->no_space_timeout);
3678 flush_workqueue(pool->wq);
3679 (void) commit(pool);
3680}
3681
3682static int check_arg_count(unsigned int argc, unsigned int args_required)
3683{
3684 if (argc != args_required) {
3685 DMWARN("Message received with %u arguments instead of %u.",
3686 argc, args_required);
3687 return -EINVAL;
3688 }
3689
3690 return 0;
3691}
3692
3693static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
3694{
3695 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
3696 *dev_id <= MAX_DEV_ID)
3697 return 0;
3698
3699 if (warning)
3700 DMWARN("Message received with invalid device id: %s", arg);
3701
3702 return -EINVAL;
3703}
3704
3705static int process_create_thin_mesg(unsigned int argc, char **argv, struct pool *pool)
3706{
3707 dm_thin_id dev_id;
3708 int r;
3709
3710 r = check_arg_count(argc, 2);
3711 if (r)
3712 return r;
3713
3714 r = read_dev_id(argv[1], &dev_id, 1);
3715 if (r)
3716 return r;
3717
3718 r = dm_pool_create_thin(pool->pmd, dev_id);
3719 if (r) {
3720 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
3721 argv[1]);
3722 return r;
3723 }
3724
3725 return 0;
3726}
3727
3728static int process_create_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3729{
3730 dm_thin_id dev_id;
3731 dm_thin_id origin_dev_id;
3732 int r;
3733
3734 r = check_arg_count(argc, 3);
3735 if (r)
3736 return r;
3737
3738 r = read_dev_id(argv[1], &dev_id, 1);
3739 if (r)
3740 return r;
3741
3742 r = read_dev_id(argv[2], &origin_dev_id, 1);
3743 if (r)
3744 return r;
3745
3746 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
3747 if (r) {
3748 DMWARN("Creation of new snapshot %s of device %s failed.",
3749 argv[1], argv[2]);
3750 return r;
3751 }
3752
3753 return 0;
3754}
3755
3756static int process_delete_mesg(unsigned int argc, char **argv, struct pool *pool)
3757{
3758 dm_thin_id dev_id;
3759 int r;
3760
3761 r = check_arg_count(argc, 2);
3762 if (r)
3763 return r;
3764
3765 r = read_dev_id(argv[1], &dev_id, 1);
3766 if (r)
3767 return r;
3768
3769 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
3770 if (r)
3771 DMWARN("Deletion of thin device %s failed.", argv[1]);
3772
3773 return r;
3774}
3775
3776static int process_set_transaction_id_mesg(unsigned int argc, char **argv, struct pool *pool)
3777{
3778 dm_thin_id old_id, new_id;
3779 int r;
3780
3781 r = check_arg_count(argc, 3);
3782 if (r)
3783 return r;
3784
3785 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
3786 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
3787 return -EINVAL;
3788 }
3789
3790 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
3791 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
3792 return -EINVAL;
3793 }
3794
3795 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
3796 if (r) {
3797 DMWARN("Failed to change transaction id from %s to %s.",
3798 argv[1], argv[2]);
3799 return r;
3800 }
3801
3802 return 0;
3803}
3804
3805static int process_reserve_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3806{
3807 int r;
3808
3809 r = check_arg_count(argc, 1);
3810 if (r)
3811 return r;
3812
3813 (void) commit(pool);
3814
3815 r = dm_pool_reserve_metadata_snap(pool->pmd);
3816 if (r)
3817 DMWARN("reserve_metadata_snap message failed.");
3818
3819 return r;
3820}
3821
3822static int process_release_metadata_snap_mesg(unsigned int argc, char **argv, struct pool *pool)
3823{
3824 int r;
3825
3826 r = check_arg_count(argc, 1);
3827 if (r)
3828 return r;
3829
3830 r = dm_pool_release_metadata_snap(pool->pmd);
3831 if (r)
3832 DMWARN("release_metadata_snap message failed.");
3833
3834 return r;
3835}
3836
3837/*
3838 * Messages supported:
3839 * create_thin <dev_id>
3840 * create_snap <dev_id> <origin_id>
3841 * delete <dev_id>
3842 * set_transaction_id <current_trans_id> <new_trans_id>
3843 * reserve_metadata_snap
3844 * release_metadata_snap
3845 */
3846static int pool_message(struct dm_target *ti, unsigned int argc, char **argv,
3847 char *result, unsigned int maxlen)
3848{
3849 int r = -EINVAL;
3850 struct pool_c *pt = ti->private;
3851 struct pool *pool = pt->pool;
3852
3853 if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) {
3854 DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
3855 dm_device_name(pool->pool_md));
3856 return -EOPNOTSUPP;
3857 }
3858
3859 if (!strcasecmp(argv[0], "create_thin"))
3860 r = process_create_thin_mesg(argc, argv, pool);
3861
3862 else if (!strcasecmp(argv[0], "create_snap"))
3863 r = process_create_snap_mesg(argc, argv, pool);
3864
3865 else if (!strcasecmp(argv[0], "delete"))
3866 r = process_delete_mesg(argc, argv, pool);
3867
3868 else if (!strcasecmp(argv[0], "set_transaction_id"))
3869 r = process_set_transaction_id_mesg(argc, argv, pool);
3870
3871 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
3872 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
3873
3874 else if (!strcasecmp(argv[0], "release_metadata_snap"))
3875 r = process_release_metadata_snap_mesg(argc, argv, pool);
3876
3877 else
3878 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
3879
3880 if (!r)
3881 (void) commit(pool);
3882
3883 return r;
3884}
3885
3886static void emit_flags(struct pool_features *pf, char *result,
3887 unsigned int sz, unsigned int maxlen)
3888{
3889 unsigned int count = !pf->zero_new_blocks + !pf->discard_enabled +
3890 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
3891 pf->error_if_no_space;
3892 DMEMIT("%u ", count);
3893
3894 if (!pf->zero_new_blocks)
3895 DMEMIT("skip_block_zeroing ");
3896
3897 if (!pf->discard_enabled)
3898 DMEMIT("ignore_discard ");
3899
3900 if (!pf->discard_passdown)
3901 DMEMIT("no_discard_passdown ");
3902
3903 if (pf->mode == PM_READ_ONLY)
3904 DMEMIT("read_only ");
3905
3906 if (pf->error_if_no_space)
3907 DMEMIT("error_if_no_space ");
3908}
3909
3910/*
3911 * Status line is:
3912 * <transaction id> <used metadata sectors>/<total metadata sectors>
3913 * <used data sectors>/<total data sectors> <held metadata root>
3914 * <pool mode> <discard config> <no space config> <needs_check>
3915 */
3916static void pool_status(struct dm_target *ti, status_type_t type,
3917 unsigned int status_flags, char *result, unsigned int maxlen)
3918{
3919 int r;
3920 unsigned int sz = 0;
3921 uint64_t transaction_id;
3922 dm_block_t nr_free_blocks_data;
3923 dm_block_t nr_free_blocks_metadata;
3924 dm_block_t nr_blocks_data;
3925 dm_block_t nr_blocks_metadata;
3926 dm_block_t held_root;
3927 enum pool_mode mode;
3928 char buf[BDEVNAME_SIZE];
3929 char buf2[BDEVNAME_SIZE];
3930 struct pool_c *pt = ti->private;
3931 struct pool *pool = pt->pool;
3932
3933 switch (type) {
3934 case STATUSTYPE_INFO:
3935 if (get_pool_mode(pool) == PM_FAIL) {
3936 DMEMIT("Fail");
3937 break;
3938 }
3939
3940 /* Commit to ensure statistics aren't out-of-date */
3941 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
3942 (void) commit(pool);
3943
3944 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
3945 if (r) {
3946 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
3947 dm_device_name(pool->pool_md), r);
3948 goto err;
3949 }
3950
3951 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
3952 if (r) {
3953 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
3954 dm_device_name(pool->pool_md), r);
3955 goto err;
3956 }
3957
3958 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
3959 if (r) {
3960 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
3961 dm_device_name(pool->pool_md), r);
3962 goto err;
3963 }
3964
3965 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
3966 if (r) {
3967 DMERR("%s: dm_pool_get_free_block_count returned %d",
3968 dm_device_name(pool->pool_md), r);
3969 goto err;
3970 }
3971
3972 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
3973 if (r) {
3974 DMERR("%s: dm_pool_get_data_dev_size returned %d",
3975 dm_device_name(pool->pool_md), r);
3976 goto err;
3977 }
3978
3979 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
3980 if (r) {
3981 DMERR("%s: dm_pool_get_metadata_snap returned %d",
3982 dm_device_name(pool->pool_md), r);
3983 goto err;
3984 }
3985
3986 DMEMIT("%llu %llu/%llu %llu/%llu ",
3987 (unsigned long long)transaction_id,
3988 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
3989 (unsigned long long)nr_blocks_metadata,
3990 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
3991 (unsigned long long)nr_blocks_data);
3992
3993 if (held_root)
3994 DMEMIT("%llu ", held_root);
3995 else
3996 DMEMIT("- ");
3997
3998 mode = get_pool_mode(pool);
3999 if (mode == PM_OUT_OF_DATA_SPACE)
4000 DMEMIT("out_of_data_space ");
4001 else if (is_read_only_pool_mode(mode))
4002 DMEMIT("ro ");
4003 else
4004 DMEMIT("rw ");
4005
4006 if (!pool->pf.discard_enabled)
4007 DMEMIT("ignore_discard ");
4008 else if (pool->pf.discard_passdown)
4009 DMEMIT("discard_passdown ");
4010 else
4011 DMEMIT("no_discard_passdown ");
4012
4013 if (pool->pf.error_if_no_space)
4014 DMEMIT("error_if_no_space ");
4015 else
4016 DMEMIT("queue_if_no_space ");
4017
4018 if (dm_pool_metadata_needs_check(pool->pmd))
4019 DMEMIT("needs_check ");
4020 else
4021 DMEMIT("- ");
4022
4023 DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt));
4024
4025 break;
4026
4027 case STATUSTYPE_TABLE:
4028 DMEMIT("%s %s %lu %llu ",
4029 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
4030 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
4031 (unsigned long)pool->sectors_per_block,
4032 (unsigned long long)pt->low_water_blocks);
4033 emit_flags(&pt->requested_pf, result, sz, maxlen);
4034 break;
4035
4036 case STATUSTYPE_IMA:
4037 *result = '\0';
4038 break;
4039 }
4040 return;
4041
4042err:
4043 DMEMIT("Error");
4044}
4045
4046static int pool_iterate_devices(struct dm_target *ti,
4047 iterate_devices_callout_fn fn, void *data)
4048{
4049 struct pool_c *pt = ti->private;
4050
4051 return fn(ti, pt->data_dev, 0, ti->len, data);
4052}
4053
4054static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
4055{
4056 struct pool_c *pt = ti->private;
4057 struct pool *pool = pt->pool;
4058 sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
4059
4060 /*
4061 * If max_sectors is smaller than pool->sectors_per_block adjust it
4062 * to the highest possible power-of-2 factor of pool->sectors_per_block.
4063 * This is especially beneficial when the pool's data device is a RAID
4064 * device that has a full stripe width that matches pool->sectors_per_block
4065 * -- because even though partial RAID stripe-sized IOs will be issued to a
4066 * single RAID stripe; when aggregated they will end on a full RAID stripe
4067 * boundary.. which avoids additional partial RAID stripe writes cascading
4068 */
4069 if (limits->max_sectors < pool->sectors_per_block) {
4070 while (!is_factor(pool->sectors_per_block, limits->max_sectors)) {
4071 if ((limits->max_sectors & (limits->max_sectors - 1)) == 0)
4072 limits->max_sectors--;
4073 limits->max_sectors = rounddown_pow_of_two(limits->max_sectors);
4074 }
4075 }
4076
4077 /*
4078 * If the system-determined stacked limits are compatible with the
4079 * pool's blocksize (io_opt is a factor) do not override them.
4080 */
4081 if (io_opt_sectors < pool->sectors_per_block ||
4082 !is_factor(io_opt_sectors, pool->sectors_per_block)) {
4083 if (is_factor(pool->sectors_per_block, limits->max_sectors))
4084 blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT);
4085 else
4086 blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
4087 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
4088 }
4089
4090 /*
4091 * pt->adjusted_pf is a staging area for the actual features to use.
4092 * They get transferred to the live pool in bind_control_target()
4093 * called from pool_preresume().
4094 */
4095
4096 if (pt->adjusted_pf.discard_enabled) {
4097 disable_discard_passdown_if_not_supported(pt);
4098 if (!pt->adjusted_pf.discard_passdown)
4099 limits->max_discard_sectors = 0;
4100 /*
4101 * The pool uses the same discard limits as the underlying data
4102 * device. DM core has already set this up.
4103 */
4104 } else {
4105 /*
4106 * Must explicitly disallow stacking discard limits otherwise the
4107 * block layer will stack them if pool's data device has support.
4108 */
4109 limits->discard_granularity = 0;
4110 }
4111}
4112
4113static struct target_type pool_target = {
4114 .name = "thin-pool",
4115 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
4116 DM_TARGET_IMMUTABLE,
4117 .version = {1, 23, 0},
4118 .module = THIS_MODULE,
4119 .ctr = pool_ctr,
4120 .dtr = pool_dtr,
4121 .map = pool_map,
4122 .presuspend = pool_presuspend,
4123 .presuspend_undo = pool_presuspend_undo,
4124 .postsuspend = pool_postsuspend,
4125 .preresume = pool_preresume,
4126 .resume = pool_resume,
4127 .message = pool_message,
4128 .status = pool_status,
4129 .iterate_devices = pool_iterate_devices,
4130 .io_hints = pool_io_hints,
4131};
4132
4133/*
4134 *--------------------------------------------------------------
4135 * Thin target methods
4136 *--------------------------------------------------------------
4137 */
4138static void thin_get(struct thin_c *tc)
4139{
4140 refcount_inc(&tc->refcount);
4141}
4142
4143static void thin_put(struct thin_c *tc)
4144{
4145 if (refcount_dec_and_test(&tc->refcount))
4146 complete(&tc->can_destroy);
4147}
4148
4149static void thin_dtr(struct dm_target *ti)
4150{
4151 struct thin_c *tc = ti->private;
4152
4153 spin_lock_irq(&tc->pool->lock);
4154 list_del_rcu(&tc->list);
4155 spin_unlock_irq(&tc->pool->lock);
4156 synchronize_rcu();
4157
4158 thin_put(tc);
4159 wait_for_completion(&tc->can_destroy);
4160
4161 mutex_lock(&dm_thin_pool_table.mutex);
4162
4163 __pool_dec(tc->pool);
4164 dm_pool_close_thin_device(tc->td);
4165 dm_put_device(ti, tc->pool_dev);
4166 if (tc->origin_dev)
4167 dm_put_device(ti, tc->origin_dev);
4168 kfree(tc);
4169
4170 mutex_unlock(&dm_thin_pool_table.mutex);
4171}
4172
4173/*
4174 * Thin target parameters:
4175 *
4176 * <pool_dev> <dev_id> [origin_dev]
4177 *
4178 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
4179 * dev_id: the internal device identifier
4180 * origin_dev: a device external to the pool that should act as the origin
4181 *
4182 * If the pool device has discards disabled, they get disabled for the thin
4183 * device as well.
4184 */
4185static int thin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
4186{
4187 int r;
4188 struct thin_c *tc;
4189 struct dm_dev *pool_dev, *origin_dev;
4190 struct mapped_device *pool_md;
4191
4192 mutex_lock(&dm_thin_pool_table.mutex);
4193
4194 if (argc != 2 && argc != 3) {
4195 ti->error = "Invalid argument count";
4196 r = -EINVAL;
4197 goto out_unlock;
4198 }
4199
4200 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
4201 if (!tc) {
4202 ti->error = "Out of memory";
4203 r = -ENOMEM;
4204 goto out_unlock;
4205 }
4206 tc->thin_md = dm_table_get_md(ti->table);
4207 spin_lock_init(&tc->lock);
4208 INIT_LIST_HEAD(&tc->deferred_cells);
4209 bio_list_init(&tc->deferred_bio_list);
4210 bio_list_init(&tc->retry_on_resume_list);
4211 tc->sort_bio_list = RB_ROOT;
4212
4213 if (argc == 3) {
4214 if (!strcmp(argv[0], argv[2])) {
4215 ti->error = "Error setting origin device";
4216 r = -EINVAL;
4217 goto bad_origin_dev;
4218 }
4219
4220 r = dm_get_device(ti, argv[2], BLK_OPEN_READ, &origin_dev);
4221 if (r) {
4222 ti->error = "Error opening origin device";
4223 goto bad_origin_dev;
4224 }
4225 tc->origin_dev = origin_dev;
4226 }
4227
4228 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
4229 if (r) {
4230 ti->error = "Error opening pool device";
4231 goto bad_pool_dev;
4232 }
4233 tc->pool_dev = pool_dev;
4234
4235 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
4236 ti->error = "Invalid device id";
4237 r = -EINVAL;
4238 goto bad_common;
4239 }
4240
4241 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
4242 if (!pool_md) {
4243 ti->error = "Couldn't get pool mapped device";
4244 r = -EINVAL;
4245 goto bad_common;
4246 }
4247
4248 tc->pool = __pool_table_lookup(pool_md);
4249 if (!tc->pool) {
4250 ti->error = "Couldn't find pool object";
4251 r = -EINVAL;
4252 goto bad_pool_lookup;
4253 }
4254 __pool_inc(tc->pool);
4255
4256 if (get_pool_mode(tc->pool) == PM_FAIL) {
4257 ti->error = "Couldn't open thin device, Pool is in fail mode";
4258 r = -EINVAL;
4259 goto bad_pool;
4260 }
4261
4262 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
4263 if (r) {
4264 ti->error = "Couldn't open thin internal device";
4265 goto bad_pool;
4266 }
4267
4268 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
4269 if (r)
4270 goto bad;
4271
4272 ti->num_flush_bios = 1;
4273 ti->limit_swap_bios = true;
4274 ti->flush_supported = true;
4275 ti->accounts_remapped_io = true;
4276 ti->per_io_data_size = sizeof(struct dm_thin_endio_hook);
4277
4278 /* In case the pool supports discards, pass them on. */
4279 if (tc->pool->pf.discard_enabled) {
4280 ti->discards_supported = true;
4281 ti->num_discard_bios = 1;
4282 ti->max_discard_granularity = true;
4283 }
4284
4285 mutex_unlock(&dm_thin_pool_table.mutex);
4286
4287 spin_lock_irq(&tc->pool->lock);
4288 if (tc->pool->suspended) {
4289 spin_unlock_irq(&tc->pool->lock);
4290 mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
4291 ti->error = "Unable to activate thin device while pool is suspended";
4292 r = -EINVAL;
4293 goto bad;
4294 }
4295 refcount_set(&tc->refcount, 1);
4296 init_completion(&tc->can_destroy);
4297 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
4298 spin_unlock_irq(&tc->pool->lock);
4299 /*
4300 * This synchronize_rcu() call is needed here otherwise we risk a
4301 * wake_worker() call finding no bios to process (because the newly
4302 * added tc isn't yet visible). So this reduces latency since we
4303 * aren't then dependent on the periodic commit to wake_worker().
4304 */
4305 synchronize_rcu();
4306
4307 dm_put(pool_md);
4308
4309 return 0;
4310
4311bad:
4312 dm_pool_close_thin_device(tc->td);
4313bad_pool:
4314 __pool_dec(tc->pool);
4315bad_pool_lookup:
4316 dm_put(pool_md);
4317bad_common:
4318 dm_put_device(ti, tc->pool_dev);
4319bad_pool_dev:
4320 if (tc->origin_dev)
4321 dm_put_device(ti, tc->origin_dev);
4322bad_origin_dev:
4323 kfree(tc);
4324out_unlock:
4325 mutex_unlock(&dm_thin_pool_table.mutex);
4326
4327 return r;
4328}
4329
4330static int thin_map(struct dm_target *ti, struct bio *bio)
4331{
4332 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
4333
4334 return thin_bio_map(ti, bio);
4335}
4336
4337static int thin_endio(struct dm_target *ti, struct bio *bio,
4338 blk_status_t *err)
4339{
4340 unsigned long flags;
4341 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
4342 struct list_head work;
4343 struct dm_thin_new_mapping *m, *tmp;
4344 struct pool *pool = h->tc->pool;
4345
4346 if (h->shared_read_entry) {
4347 INIT_LIST_HEAD(&work);
4348 dm_deferred_entry_dec(h->shared_read_entry, &work);
4349
4350 spin_lock_irqsave(&pool->lock, flags);
4351 list_for_each_entry_safe(m, tmp, &work, list) {
4352 list_del(&m->list);
4353 __complete_mapping_preparation(m);
4354 }
4355 spin_unlock_irqrestore(&pool->lock, flags);
4356 }
4357
4358 if (h->all_io_entry) {
4359 INIT_LIST_HEAD(&work);
4360 dm_deferred_entry_dec(h->all_io_entry, &work);
4361 if (!list_empty(&work)) {
4362 spin_lock_irqsave(&pool->lock, flags);
4363 list_for_each_entry_safe(m, tmp, &work, list)
4364 list_add_tail(&m->list, &pool->prepared_discards);
4365 spin_unlock_irqrestore(&pool->lock, flags);
4366 wake_worker(pool);
4367 }
4368 }
4369
4370 if (h->cell)
4371 cell_defer_no_holder(h->tc, h->cell);
4372
4373 return DM_ENDIO_DONE;
4374}
4375
4376static void thin_presuspend(struct dm_target *ti)
4377{
4378 struct thin_c *tc = ti->private;
4379
4380 if (dm_noflush_suspending(ti))
4381 noflush_work(tc, do_noflush_start);
4382}
4383
4384static void thin_postsuspend(struct dm_target *ti)
4385{
4386 struct thin_c *tc = ti->private;
4387
4388 /*
4389 * The dm_noflush_suspending flag has been cleared by now, so
4390 * unfortunately we must always run this.
4391 */
4392 noflush_work(tc, do_noflush_stop);
4393}
4394
4395static int thin_preresume(struct dm_target *ti)
4396{
4397 struct thin_c *tc = ti->private;
4398
4399 if (tc->origin_dev)
4400 tc->origin_size = get_dev_size(tc->origin_dev->bdev);
4401
4402 return 0;
4403}
4404
4405/*
4406 * <nr mapped sectors> <highest mapped sector>
4407 */
4408static void thin_status(struct dm_target *ti, status_type_t type,
4409 unsigned int status_flags, char *result, unsigned int maxlen)
4410{
4411 int r;
4412 ssize_t sz = 0;
4413 dm_block_t mapped, highest;
4414 char buf[BDEVNAME_SIZE];
4415 struct thin_c *tc = ti->private;
4416
4417 if (get_pool_mode(tc->pool) == PM_FAIL) {
4418 DMEMIT("Fail");
4419 return;
4420 }
4421
4422 if (!tc->td)
4423 DMEMIT("-");
4424 else {
4425 switch (type) {
4426 case STATUSTYPE_INFO:
4427 r = dm_thin_get_mapped_count(tc->td, &mapped);
4428 if (r) {
4429 DMERR("dm_thin_get_mapped_count returned %d", r);
4430 goto err;
4431 }
4432
4433 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
4434 if (r < 0) {
4435 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
4436 goto err;
4437 }
4438
4439 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
4440 if (r)
4441 DMEMIT("%llu", ((highest + 1) *
4442 tc->pool->sectors_per_block) - 1);
4443 else
4444 DMEMIT("-");
4445 break;
4446
4447 case STATUSTYPE_TABLE:
4448 DMEMIT("%s %lu",
4449 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
4450 (unsigned long) tc->dev_id);
4451 if (tc->origin_dev)
4452 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
4453 break;
4454
4455 case STATUSTYPE_IMA:
4456 *result = '\0';
4457 break;
4458 }
4459 }
4460
4461 return;
4462
4463err:
4464 DMEMIT("Error");
4465}
4466
4467static int thin_iterate_devices(struct dm_target *ti,
4468 iterate_devices_callout_fn fn, void *data)
4469{
4470 sector_t blocks;
4471 struct thin_c *tc = ti->private;
4472 struct pool *pool = tc->pool;
4473
4474 /*
4475 * We can't call dm_pool_get_data_dev_size() since that blocks. So
4476 * we follow a more convoluted path through to the pool's target.
4477 */
4478 if (!pool->ti)
4479 return 0; /* nothing is bound */
4480
4481 blocks = pool->ti->len;
4482 (void) sector_div(blocks, pool->sectors_per_block);
4483 if (blocks)
4484 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
4485
4486 return 0;
4487}
4488
4489static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
4490{
4491 struct thin_c *tc = ti->private;
4492 struct pool *pool = tc->pool;
4493
4494 if (pool->pf.discard_enabled) {
4495 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
4496 limits->max_discard_sectors = pool->sectors_per_block * BIO_PRISON_MAX_RANGE;
4497 }
4498}
4499
4500static struct target_type thin_target = {
4501 .name = "thin",
4502 .version = {1, 23, 0},
4503 .module = THIS_MODULE,
4504 .ctr = thin_ctr,
4505 .dtr = thin_dtr,
4506 .map = thin_map,
4507 .end_io = thin_endio,
4508 .preresume = thin_preresume,
4509 .presuspend = thin_presuspend,
4510 .postsuspend = thin_postsuspend,
4511 .status = thin_status,
4512 .iterate_devices = thin_iterate_devices,
4513 .io_hints = thin_io_hints,
4514};
4515
4516/*----------------------------------------------------------------*/
4517
4518static int __init dm_thin_init(void)
4519{
4520 int r = -ENOMEM;
4521
4522 pool_table_init();
4523
4524 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
4525 if (!_new_mapping_cache)
4526 return r;
4527
4528 r = dm_register_target(&thin_target);
4529 if (r)
4530 goto bad_new_mapping_cache;
4531
4532 r = dm_register_target(&pool_target);
4533 if (r)
4534 goto bad_thin_target;
4535
4536 return 0;
4537
4538bad_thin_target:
4539 dm_unregister_target(&thin_target);
4540bad_new_mapping_cache:
4541 kmem_cache_destroy(_new_mapping_cache);
4542
4543 return r;
4544}
4545
4546static void dm_thin_exit(void)
4547{
4548 dm_unregister_target(&thin_target);
4549 dm_unregister_target(&pool_target);
4550
4551 kmem_cache_destroy(_new_mapping_cache);
4552
4553 pool_table_exit();
4554}
4555
4556module_init(dm_thin_init);
4557module_exit(dm_thin_exit);
4558
4559module_param_named(no_space_timeout, no_space_timeout_secs, uint, 0644);
4560MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
4561
4562MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
4563MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
4564MODULE_LICENSE("GPL");
1/*
2 * Copyright (C) 2011-2012 Red Hat UK.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-thin-metadata.h"
8#include "dm-bio-prison.h"
9#include "dm.h"
10
11#include <linux/device-mapper.h>
12#include <linux/dm-io.h>
13#include <linux/dm-kcopyd.h>
14#include <linux/list.h>
15#include <linux/rculist.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/rbtree.h>
20
21#define DM_MSG_PREFIX "thin"
22
23/*
24 * Tunable constants
25 */
26#define ENDIO_HOOK_POOL_SIZE 1024
27#define MAPPING_POOL_SIZE 1024
28#define PRISON_CELLS 1024
29#define COMMIT_PERIOD HZ
30#define NO_SPACE_TIMEOUT_SECS 60
31
32static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
33
34DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
35 "A percentage of time allocated for copy on write");
36
37/*
38 * The block size of the device holding pool data must be
39 * between 64KB and 1GB.
40 */
41#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
42#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
43
44/*
45 * Device id is restricted to 24 bits.
46 */
47#define MAX_DEV_ID ((1 << 24) - 1)
48
49/*
50 * How do we handle breaking sharing of data blocks?
51 * =================================================
52 *
53 * We use a standard copy-on-write btree to store the mappings for the
54 * devices (note I'm talking about copy-on-write of the metadata here, not
55 * the data). When you take an internal snapshot you clone the root node
56 * of the origin btree. After this there is no concept of an origin or a
57 * snapshot. They are just two device trees that happen to point to the
58 * same data blocks.
59 *
60 * When we get a write in we decide if it's to a shared data block using
61 * some timestamp magic. If it is, we have to break sharing.
62 *
63 * Let's say we write to a shared block in what was the origin. The
64 * steps are:
65 *
66 * i) plug io further to this physical block. (see bio_prison code).
67 *
68 * ii) quiesce any read io to that shared data block. Obviously
69 * including all devices that share this block. (see dm_deferred_set code)
70 *
71 * iii) copy the data block to a newly allocate block. This step can be
72 * missed out if the io covers the block. (schedule_copy).
73 *
74 * iv) insert the new mapping into the origin's btree
75 * (process_prepared_mapping). This act of inserting breaks some
76 * sharing of btree nodes between the two devices. Breaking sharing only
77 * effects the btree of that specific device. Btrees for the other
78 * devices that share the block never change. The btree for the origin
79 * device as it was after the last commit is untouched, ie. we're using
80 * persistent data structures in the functional programming sense.
81 *
82 * v) unplug io to this physical block, including the io that triggered
83 * the breaking of sharing.
84 *
85 * Steps (ii) and (iii) occur in parallel.
86 *
87 * The metadata _doesn't_ need to be committed before the io continues. We
88 * get away with this because the io is always written to a _new_ block.
89 * If there's a crash, then:
90 *
91 * - The origin mapping will point to the old origin block (the shared
92 * one). This will contain the data as it was before the io that triggered
93 * the breaking of sharing came in.
94 *
95 * - The snap mapping still points to the old block. As it would after
96 * the commit.
97 *
98 * The downside of this scheme is the timestamp magic isn't perfect, and
99 * will continue to think that data block in the snapshot device is shared
100 * even after the write to the origin has broken sharing. I suspect data
101 * blocks will typically be shared by many different devices, so we're
102 * breaking sharing n + 1 times, rather than n, where n is the number of
103 * devices that reference this data block. At the moment I think the
104 * benefits far, far outweigh the disadvantages.
105 */
106
107/*----------------------------------------------------------------*/
108
109/*
110 * Key building.
111 */
112static void build_data_key(struct dm_thin_device *td,
113 dm_block_t b, struct dm_cell_key *key)
114{
115 key->virtual = 0;
116 key->dev = dm_thin_dev_id(td);
117 key->block = b;
118}
119
120static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
121 struct dm_cell_key *key)
122{
123 key->virtual = 1;
124 key->dev = dm_thin_dev_id(td);
125 key->block = b;
126}
127
128/*----------------------------------------------------------------*/
129
130/*
131 * A pool device ties together a metadata device and a data device. It
132 * also provides the interface for creating and destroying internal
133 * devices.
134 */
135struct dm_thin_new_mapping;
136
137/*
138 * The pool runs in 4 modes. Ordered in degraded order for comparisons.
139 */
140enum pool_mode {
141 PM_WRITE, /* metadata may be changed */
142 PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
143 PM_READ_ONLY, /* metadata may not be changed */
144 PM_FAIL, /* all I/O fails */
145};
146
147struct pool_features {
148 enum pool_mode mode;
149
150 bool zero_new_blocks:1;
151 bool discard_enabled:1;
152 bool discard_passdown:1;
153 bool error_if_no_space:1;
154};
155
156struct thin_c;
157typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
158typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
159
160struct pool {
161 struct list_head list;
162 struct dm_target *ti; /* Only set if a pool target is bound */
163
164 struct mapped_device *pool_md;
165 struct block_device *md_dev;
166 struct dm_pool_metadata *pmd;
167
168 dm_block_t low_water_blocks;
169 uint32_t sectors_per_block;
170 int sectors_per_block_shift;
171
172 struct pool_features pf;
173 bool low_water_triggered:1; /* A dm event has been sent */
174
175 struct dm_bio_prison *prison;
176 struct dm_kcopyd_client *copier;
177
178 struct workqueue_struct *wq;
179 struct work_struct worker;
180 struct delayed_work waker;
181 struct delayed_work no_space_timeout;
182
183 unsigned long last_commit_jiffies;
184 unsigned ref_count;
185
186 spinlock_t lock;
187 struct bio_list deferred_flush_bios;
188 struct list_head prepared_mappings;
189 struct list_head prepared_discards;
190 struct list_head active_thins;
191
192 struct dm_deferred_set *shared_read_ds;
193 struct dm_deferred_set *all_io_ds;
194
195 struct dm_thin_new_mapping *next_mapping;
196 mempool_t *mapping_pool;
197
198 process_bio_fn process_bio;
199 process_bio_fn process_discard;
200
201 process_mapping_fn process_prepared_mapping;
202 process_mapping_fn process_prepared_discard;
203};
204
205static enum pool_mode get_pool_mode(struct pool *pool);
206static void metadata_operation_failed(struct pool *pool, const char *op, int r);
207
208/*
209 * Target context for a pool.
210 */
211struct pool_c {
212 struct dm_target *ti;
213 struct pool *pool;
214 struct dm_dev *data_dev;
215 struct dm_dev *metadata_dev;
216 struct dm_target_callbacks callbacks;
217
218 dm_block_t low_water_blocks;
219 struct pool_features requested_pf; /* Features requested during table load */
220 struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
221};
222
223/*
224 * Target context for a thin.
225 */
226struct thin_c {
227 struct list_head list;
228 struct dm_dev *pool_dev;
229 struct dm_dev *origin_dev;
230 dm_thin_id dev_id;
231
232 struct pool *pool;
233 struct dm_thin_device *td;
234 bool requeue_mode:1;
235 spinlock_t lock;
236 struct bio_list deferred_bio_list;
237 struct bio_list retry_on_resume_list;
238 struct rb_root sort_bio_list; /* sorted list of deferred bios */
239
240 /*
241 * Ensures the thin is not destroyed until the worker has finished
242 * iterating the active_thins list.
243 */
244 atomic_t refcount;
245 struct completion can_destroy;
246};
247
248/*----------------------------------------------------------------*/
249
250/*
251 * wake_worker() is used when new work is queued and when pool_resume is
252 * ready to continue deferred IO processing.
253 */
254static void wake_worker(struct pool *pool)
255{
256 queue_work(pool->wq, &pool->worker);
257}
258
259/*----------------------------------------------------------------*/
260
261static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
262 struct dm_bio_prison_cell **cell_result)
263{
264 int r;
265 struct dm_bio_prison_cell *cell_prealloc;
266
267 /*
268 * Allocate a cell from the prison's mempool.
269 * This might block but it can't fail.
270 */
271 cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
272
273 r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
274 if (r)
275 /*
276 * We reused an old cell; we can get rid of
277 * the new one.
278 */
279 dm_bio_prison_free_cell(pool->prison, cell_prealloc);
280
281 return r;
282}
283
284static void cell_release(struct pool *pool,
285 struct dm_bio_prison_cell *cell,
286 struct bio_list *bios)
287{
288 dm_cell_release(pool->prison, cell, bios);
289 dm_bio_prison_free_cell(pool->prison, cell);
290}
291
292static void cell_release_no_holder(struct pool *pool,
293 struct dm_bio_prison_cell *cell,
294 struct bio_list *bios)
295{
296 dm_cell_release_no_holder(pool->prison, cell, bios);
297 dm_bio_prison_free_cell(pool->prison, cell);
298}
299
300static void cell_defer_no_holder_no_free(struct thin_c *tc,
301 struct dm_bio_prison_cell *cell)
302{
303 struct pool *pool = tc->pool;
304 unsigned long flags;
305
306 spin_lock_irqsave(&tc->lock, flags);
307 dm_cell_release_no_holder(pool->prison, cell, &tc->deferred_bio_list);
308 spin_unlock_irqrestore(&tc->lock, flags);
309
310 wake_worker(pool);
311}
312
313static void cell_error(struct pool *pool,
314 struct dm_bio_prison_cell *cell)
315{
316 dm_cell_error(pool->prison, cell);
317 dm_bio_prison_free_cell(pool->prison, cell);
318}
319
320/*----------------------------------------------------------------*/
321
322/*
323 * A global list of pools that uses a struct mapped_device as a key.
324 */
325static struct dm_thin_pool_table {
326 struct mutex mutex;
327 struct list_head pools;
328} dm_thin_pool_table;
329
330static void pool_table_init(void)
331{
332 mutex_init(&dm_thin_pool_table.mutex);
333 INIT_LIST_HEAD(&dm_thin_pool_table.pools);
334}
335
336static void __pool_table_insert(struct pool *pool)
337{
338 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
339 list_add(&pool->list, &dm_thin_pool_table.pools);
340}
341
342static void __pool_table_remove(struct pool *pool)
343{
344 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
345 list_del(&pool->list);
346}
347
348static struct pool *__pool_table_lookup(struct mapped_device *md)
349{
350 struct pool *pool = NULL, *tmp;
351
352 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
353
354 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
355 if (tmp->pool_md == md) {
356 pool = tmp;
357 break;
358 }
359 }
360
361 return pool;
362}
363
364static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
365{
366 struct pool *pool = NULL, *tmp;
367
368 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
369
370 list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
371 if (tmp->md_dev == md_dev) {
372 pool = tmp;
373 break;
374 }
375 }
376
377 return pool;
378}
379
380/*----------------------------------------------------------------*/
381
382struct dm_thin_endio_hook {
383 struct thin_c *tc;
384 struct dm_deferred_entry *shared_read_entry;
385 struct dm_deferred_entry *all_io_entry;
386 struct dm_thin_new_mapping *overwrite_mapping;
387 struct rb_node rb_node;
388};
389
390static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
391{
392 struct bio *bio;
393 struct bio_list bios;
394 unsigned long flags;
395
396 bio_list_init(&bios);
397
398 spin_lock_irqsave(&tc->lock, flags);
399 bio_list_merge(&bios, master);
400 bio_list_init(master);
401 spin_unlock_irqrestore(&tc->lock, flags);
402
403 while ((bio = bio_list_pop(&bios)))
404 bio_endio(bio, DM_ENDIO_REQUEUE);
405}
406
407static void requeue_io(struct thin_c *tc)
408{
409 requeue_bio_list(tc, &tc->deferred_bio_list);
410 requeue_bio_list(tc, &tc->retry_on_resume_list);
411}
412
413static void error_thin_retry_list(struct thin_c *tc)
414{
415 struct bio *bio;
416 unsigned long flags;
417 struct bio_list bios;
418
419 bio_list_init(&bios);
420
421 spin_lock_irqsave(&tc->lock, flags);
422 bio_list_merge(&bios, &tc->retry_on_resume_list);
423 bio_list_init(&tc->retry_on_resume_list);
424 spin_unlock_irqrestore(&tc->lock, flags);
425
426 while ((bio = bio_list_pop(&bios)))
427 bio_io_error(bio);
428}
429
430static void error_retry_list(struct pool *pool)
431{
432 struct thin_c *tc;
433
434 rcu_read_lock();
435 list_for_each_entry_rcu(tc, &pool->active_thins, list)
436 error_thin_retry_list(tc);
437 rcu_read_unlock();
438}
439
440/*
441 * This section of code contains the logic for processing a thin device's IO.
442 * Much of the code depends on pool object resources (lists, workqueues, etc)
443 * but most is exclusively called from the thin target rather than the thin-pool
444 * target.
445 */
446
447static bool block_size_is_power_of_two(struct pool *pool)
448{
449 return pool->sectors_per_block_shift >= 0;
450}
451
452static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio)
453{
454 struct pool *pool = tc->pool;
455 sector_t block_nr = bio->bi_iter.bi_sector;
456
457 if (block_size_is_power_of_two(pool))
458 block_nr >>= pool->sectors_per_block_shift;
459 else
460 (void) sector_div(block_nr, pool->sectors_per_block);
461
462 return block_nr;
463}
464
465static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
466{
467 struct pool *pool = tc->pool;
468 sector_t bi_sector = bio->bi_iter.bi_sector;
469
470 bio->bi_bdev = tc->pool_dev->bdev;
471 if (block_size_is_power_of_two(pool))
472 bio->bi_iter.bi_sector =
473 (block << pool->sectors_per_block_shift) |
474 (bi_sector & (pool->sectors_per_block - 1));
475 else
476 bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
477 sector_div(bi_sector, pool->sectors_per_block);
478}
479
480static void remap_to_origin(struct thin_c *tc, struct bio *bio)
481{
482 bio->bi_bdev = tc->origin_dev->bdev;
483}
484
485static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
486{
487 return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
488 dm_thin_changed_this_transaction(tc->td);
489}
490
491static void inc_all_io_entry(struct pool *pool, struct bio *bio)
492{
493 struct dm_thin_endio_hook *h;
494
495 if (bio->bi_rw & REQ_DISCARD)
496 return;
497
498 h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
499 h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds);
500}
501
502static void issue(struct thin_c *tc, struct bio *bio)
503{
504 struct pool *pool = tc->pool;
505 unsigned long flags;
506
507 if (!bio_triggers_commit(tc, bio)) {
508 generic_make_request(bio);
509 return;
510 }
511
512 /*
513 * Complete bio with an error if earlier I/O caused changes to
514 * the metadata that can't be committed e.g, due to I/O errors
515 * on the metadata device.
516 */
517 if (dm_thin_aborted_changes(tc->td)) {
518 bio_io_error(bio);
519 return;
520 }
521
522 /*
523 * Batch together any bios that trigger commits and then issue a
524 * single commit for them in process_deferred_bios().
525 */
526 spin_lock_irqsave(&pool->lock, flags);
527 bio_list_add(&pool->deferred_flush_bios, bio);
528 spin_unlock_irqrestore(&pool->lock, flags);
529}
530
531static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio)
532{
533 remap_to_origin(tc, bio);
534 issue(tc, bio);
535}
536
537static void remap_and_issue(struct thin_c *tc, struct bio *bio,
538 dm_block_t block)
539{
540 remap(tc, bio, block);
541 issue(tc, bio);
542}
543
544/*----------------------------------------------------------------*/
545
546/*
547 * Bio endio functions.
548 */
549struct dm_thin_new_mapping {
550 struct list_head list;
551
552 bool quiesced:1;
553 bool prepared:1;
554 bool pass_discard:1;
555 bool definitely_not_shared:1;
556
557 int err;
558 struct thin_c *tc;
559 dm_block_t virt_block;
560 dm_block_t data_block;
561 struct dm_bio_prison_cell *cell, *cell2;
562
563 /*
564 * If the bio covers the whole area of a block then we can avoid
565 * zeroing or copying. Instead this bio is hooked. The bio will
566 * still be in the cell, so care has to be taken to avoid issuing
567 * the bio twice.
568 */
569 struct bio *bio;
570 bio_end_io_t *saved_bi_end_io;
571};
572
573static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
574{
575 struct pool *pool = m->tc->pool;
576
577 if (m->quiesced && m->prepared) {
578 list_add_tail(&m->list, &pool->prepared_mappings);
579 wake_worker(pool);
580 }
581}
582
583static void copy_complete(int read_err, unsigned long write_err, void *context)
584{
585 unsigned long flags;
586 struct dm_thin_new_mapping *m = context;
587 struct pool *pool = m->tc->pool;
588
589 m->err = read_err || write_err ? -EIO : 0;
590
591 spin_lock_irqsave(&pool->lock, flags);
592 m->prepared = true;
593 __maybe_add_mapping(m);
594 spin_unlock_irqrestore(&pool->lock, flags);
595}
596
597static void overwrite_endio(struct bio *bio, int err)
598{
599 unsigned long flags;
600 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
601 struct dm_thin_new_mapping *m = h->overwrite_mapping;
602 struct pool *pool = m->tc->pool;
603
604 m->err = err;
605
606 spin_lock_irqsave(&pool->lock, flags);
607 m->prepared = true;
608 __maybe_add_mapping(m);
609 spin_unlock_irqrestore(&pool->lock, flags);
610}
611
612/*----------------------------------------------------------------*/
613
614/*
615 * Workqueue.
616 */
617
618/*
619 * Prepared mapping jobs.
620 */
621
622/*
623 * This sends the bios in the cell back to the deferred_bios list.
624 */
625static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
626{
627 struct pool *pool = tc->pool;
628 unsigned long flags;
629
630 spin_lock_irqsave(&tc->lock, flags);
631 cell_release(pool, cell, &tc->deferred_bio_list);
632 spin_unlock_irqrestore(&tc->lock, flags);
633
634 wake_worker(pool);
635}
636
637/*
638 * Same as cell_defer above, except it omits the original holder of the cell.
639 */
640static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell)
641{
642 struct pool *pool = tc->pool;
643 unsigned long flags;
644
645 spin_lock_irqsave(&tc->lock, flags);
646 cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
647 spin_unlock_irqrestore(&tc->lock, flags);
648
649 wake_worker(pool);
650}
651
652static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m)
653{
654 if (m->bio) {
655 m->bio->bi_end_io = m->saved_bi_end_io;
656 atomic_inc(&m->bio->bi_remaining);
657 }
658 cell_error(m->tc->pool, m->cell);
659 list_del(&m->list);
660 mempool_free(m, m->tc->pool->mapping_pool);
661}
662
663static void process_prepared_mapping(struct dm_thin_new_mapping *m)
664{
665 struct thin_c *tc = m->tc;
666 struct pool *pool = tc->pool;
667 struct bio *bio;
668 int r;
669
670 bio = m->bio;
671 if (bio) {
672 bio->bi_end_io = m->saved_bi_end_io;
673 atomic_inc(&bio->bi_remaining);
674 }
675
676 if (m->err) {
677 cell_error(pool, m->cell);
678 goto out;
679 }
680
681 /*
682 * Commit the prepared block into the mapping btree.
683 * Any I/O for this block arriving after this point will get
684 * remapped to it directly.
685 */
686 r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
687 if (r) {
688 metadata_operation_failed(pool, "dm_thin_insert_block", r);
689 cell_error(pool, m->cell);
690 goto out;
691 }
692
693 /*
694 * Release any bios held while the block was being provisioned.
695 * If we are processing a write bio that completely covers the block,
696 * we already processed it so can ignore it now when processing
697 * the bios in the cell.
698 */
699 if (bio) {
700 cell_defer_no_holder(tc, m->cell);
701 bio_endio(bio, 0);
702 } else
703 cell_defer(tc, m->cell);
704
705out:
706 list_del(&m->list);
707 mempool_free(m, pool->mapping_pool);
708}
709
710static void process_prepared_discard_fail(struct dm_thin_new_mapping *m)
711{
712 struct thin_c *tc = m->tc;
713
714 bio_io_error(m->bio);
715 cell_defer_no_holder(tc, m->cell);
716 cell_defer_no_holder(tc, m->cell2);
717 mempool_free(m, tc->pool->mapping_pool);
718}
719
720static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
721{
722 struct thin_c *tc = m->tc;
723
724 inc_all_io_entry(tc->pool, m->bio);
725 cell_defer_no_holder(tc, m->cell);
726 cell_defer_no_holder(tc, m->cell2);
727
728 if (m->pass_discard)
729 if (m->definitely_not_shared)
730 remap_and_issue(tc, m->bio, m->data_block);
731 else {
732 bool used = false;
733 if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
734 bio_endio(m->bio, 0);
735 else
736 remap_and_issue(tc, m->bio, m->data_block);
737 }
738 else
739 bio_endio(m->bio, 0);
740
741 mempool_free(m, tc->pool->mapping_pool);
742}
743
744static void process_prepared_discard(struct dm_thin_new_mapping *m)
745{
746 int r;
747 struct thin_c *tc = m->tc;
748
749 r = dm_thin_remove_block(tc->td, m->virt_block);
750 if (r)
751 DMERR_LIMIT("dm_thin_remove_block() failed");
752
753 process_prepared_discard_passdown(m);
754}
755
756static void process_prepared(struct pool *pool, struct list_head *head,
757 process_mapping_fn *fn)
758{
759 unsigned long flags;
760 struct list_head maps;
761 struct dm_thin_new_mapping *m, *tmp;
762
763 INIT_LIST_HEAD(&maps);
764 spin_lock_irqsave(&pool->lock, flags);
765 list_splice_init(head, &maps);
766 spin_unlock_irqrestore(&pool->lock, flags);
767
768 list_for_each_entry_safe(m, tmp, &maps, list)
769 (*fn)(m);
770}
771
772/*
773 * Deferred bio jobs.
774 */
775static int io_overlaps_block(struct pool *pool, struct bio *bio)
776{
777 return bio->bi_iter.bi_size ==
778 (pool->sectors_per_block << SECTOR_SHIFT);
779}
780
781static int io_overwrites_block(struct pool *pool, struct bio *bio)
782{
783 return (bio_data_dir(bio) == WRITE) &&
784 io_overlaps_block(pool, bio);
785}
786
787static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
788 bio_end_io_t *fn)
789{
790 *save = bio->bi_end_io;
791 bio->bi_end_io = fn;
792}
793
794static int ensure_next_mapping(struct pool *pool)
795{
796 if (pool->next_mapping)
797 return 0;
798
799 pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
800
801 return pool->next_mapping ? 0 : -ENOMEM;
802}
803
804static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
805{
806 struct dm_thin_new_mapping *m = pool->next_mapping;
807
808 BUG_ON(!pool->next_mapping);
809
810 memset(m, 0, sizeof(struct dm_thin_new_mapping));
811 INIT_LIST_HEAD(&m->list);
812 m->bio = NULL;
813
814 pool->next_mapping = NULL;
815
816 return m;
817}
818
819static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
820 struct dm_dev *origin, dm_block_t data_origin,
821 dm_block_t data_dest,
822 struct dm_bio_prison_cell *cell, struct bio *bio)
823{
824 int r;
825 struct pool *pool = tc->pool;
826 struct dm_thin_new_mapping *m = get_next_mapping(pool);
827
828 m->tc = tc;
829 m->virt_block = virt_block;
830 m->data_block = data_dest;
831 m->cell = cell;
832
833 if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
834 m->quiesced = true;
835
836 /*
837 * IO to pool_dev remaps to the pool target's data_dev.
838 *
839 * If the whole block of data is being overwritten, we can issue the
840 * bio immediately. Otherwise we use kcopyd to clone the data first.
841 */
842 if (io_overwrites_block(pool, bio)) {
843 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
844
845 h->overwrite_mapping = m;
846 m->bio = bio;
847 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
848 inc_all_io_entry(pool, bio);
849 remap_and_issue(tc, bio, data_dest);
850 } else {
851 struct dm_io_region from, to;
852
853 from.bdev = origin->bdev;
854 from.sector = data_origin * pool->sectors_per_block;
855 from.count = pool->sectors_per_block;
856
857 to.bdev = tc->pool_dev->bdev;
858 to.sector = data_dest * pool->sectors_per_block;
859 to.count = pool->sectors_per_block;
860
861 r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
862 0, copy_complete, m);
863 if (r < 0) {
864 mempool_free(m, pool->mapping_pool);
865 DMERR_LIMIT("dm_kcopyd_copy() failed");
866 cell_error(pool, cell);
867 }
868 }
869}
870
871static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
872 dm_block_t data_origin, dm_block_t data_dest,
873 struct dm_bio_prison_cell *cell, struct bio *bio)
874{
875 schedule_copy(tc, virt_block, tc->pool_dev,
876 data_origin, data_dest, cell, bio);
877}
878
879static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
880 dm_block_t data_dest,
881 struct dm_bio_prison_cell *cell, struct bio *bio)
882{
883 schedule_copy(tc, virt_block, tc->origin_dev,
884 virt_block, data_dest, cell, bio);
885}
886
887static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
888 dm_block_t data_block, struct dm_bio_prison_cell *cell,
889 struct bio *bio)
890{
891 struct pool *pool = tc->pool;
892 struct dm_thin_new_mapping *m = get_next_mapping(pool);
893
894 m->quiesced = true;
895 m->prepared = false;
896 m->tc = tc;
897 m->virt_block = virt_block;
898 m->data_block = data_block;
899 m->cell = cell;
900
901 /*
902 * If the whole block of data is being overwritten or we are not
903 * zeroing pre-existing data, we can issue the bio immediately.
904 * Otherwise we use kcopyd to zero the data first.
905 */
906 if (!pool->pf.zero_new_blocks)
907 process_prepared_mapping(m);
908
909 else if (io_overwrites_block(pool, bio)) {
910 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
911
912 h->overwrite_mapping = m;
913 m->bio = bio;
914 save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
915 inc_all_io_entry(pool, bio);
916 remap_and_issue(tc, bio, data_block);
917 } else {
918 int r;
919 struct dm_io_region to;
920
921 to.bdev = tc->pool_dev->bdev;
922 to.sector = data_block * pool->sectors_per_block;
923 to.count = pool->sectors_per_block;
924
925 r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m);
926 if (r < 0) {
927 mempool_free(m, pool->mapping_pool);
928 DMERR_LIMIT("dm_kcopyd_zero() failed");
929 cell_error(pool, cell);
930 }
931 }
932}
933
934/*
935 * A non-zero return indicates read_only or fail_io mode.
936 * Many callers don't care about the return value.
937 */
938static int commit(struct pool *pool)
939{
940 int r;
941
942 if (get_pool_mode(pool) >= PM_READ_ONLY)
943 return -EINVAL;
944
945 r = dm_pool_commit_metadata(pool->pmd);
946 if (r)
947 metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
948
949 return r;
950}
951
952static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
953{
954 unsigned long flags;
955
956 if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
957 DMWARN("%s: reached low water mark for data device: sending event.",
958 dm_device_name(pool->pool_md));
959 spin_lock_irqsave(&pool->lock, flags);
960 pool->low_water_triggered = true;
961 spin_unlock_irqrestore(&pool->lock, flags);
962 dm_table_event(pool->ti->table);
963 }
964}
965
966static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
967
968static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
969{
970 int r;
971 dm_block_t free_blocks;
972 struct pool *pool = tc->pool;
973
974 if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
975 return -EINVAL;
976
977 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
978 if (r) {
979 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
980 return r;
981 }
982
983 check_low_water_mark(pool, free_blocks);
984
985 if (!free_blocks) {
986 /*
987 * Try to commit to see if that will free up some
988 * more space.
989 */
990 r = commit(pool);
991 if (r)
992 return r;
993
994 r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
995 if (r) {
996 metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
997 return r;
998 }
999
1000 if (!free_blocks) {
1001 set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
1002 return -ENOSPC;
1003 }
1004 }
1005
1006 r = dm_pool_alloc_data_block(pool->pmd, result);
1007 if (r) {
1008 metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
1009 return r;
1010 }
1011
1012 return 0;
1013}
1014
1015/*
1016 * If we have run out of space, queue bios until the device is
1017 * resumed, presumably after having been reloaded with more space.
1018 */
1019static void retry_on_resume(struct bio *bio)
1020{
1021 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1022 struct thin_c *tc = h->tc;
1023 unsigned long flags;
1024
1025 spin_lock_irqsave(&tc->lock, flags);
1026 bio_list_add(&tc->retry_on_resume_list, bio);
1027 spin_unlock_irqrestore(&tc->lock, flags);
1028}
1029
1030static bool should_error_unserviceable_bio(struct pool *pool)
1031{
1032 enum pool_mode m = get_pool_mode(pool);
1033
1034 switch (m) {
1035 case PM_WRITE:
1036 /* Shouldn't get here */
1037 DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
1038 return true;
1039
1040 case PM_OUT_OF_DATA_SPACE:
1041 return pool->pf.error_if_no_space;
1042
1043 case PM_READ_ONLY:
1044 case PM_FAIL:
1045 return true;
1046 default:
1047 /* Shouldn't get here */
1048 DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
1049 return true;
1050 }
1051}
1052
1053static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
1054{
1055 if (should_error_unserviceable_bio(pool))
1056 bio_io_error(bio);
1057 else
1058 retry_on_resume(bio);
1059}
1060
1061static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
1062{
1063 struct bio *bio;
1064 struct bio_list bios;
1065
1066 if (should_error_unserviceable_bio(pool)) {
1067 cell_error(pool, cell);
1068 return;
1069 }
1070
1071 bio_list_init(&bios);
1072 cell_release(pool, cell, &bios);
1073
1074 if (should_error_unserviceable_bio(pool))
1075 while ((bio = bio_list_pop(&bios)))
1076 bio_io_error(bio);
1077 else
1078 while ((bio = bio_list_pop(&bios)))
1079 retry_on_resume(bio);
1080}
1081
1082static void process_discard(struct thin_c *tc, struct bio *bio)
1083{
1084 int r;
1085 unsigned long flags;
1086 struct pool *pool = tc->pool;
1087 struct dm_bio_prison_cell *cell, *cell2;
1088 struct dm_cell_key key, key2;
1089 dm_block_t block = get_bio_block(tc, bio);
1090 struct dm_thin_lookup_result lookup_result;
1091 struct dm_thin_new_mapping *m;
1092
1093 build_virtual_key(tc->td, block, &key);
1094 if (bio_detain(tc->pool, &key, bio, &cell))
1095 return;
1096
1097 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1098 switch (r) {
1099 case 0:
1100 /*
1101 * Check nobody is fiddling with this pool block. This can
1102 * happen if someone's in the process of breaking sharing
1103 * on this block.
1104 */
1105 build_data_key(tc->td, lookup_result.block, &key2);
1106 if (bio_detain(tc->pool, &key2, bio, &cell2)) {
1107 cell_defer_no_holder(tc, cell);
1108 break;
1109 }
1110
1111 if (io_overlaps_block(pool, bio)) {
1112 /*
1113 * IO may still be going to the destination block. We must
1114 * quiesce before we can do the removal.
1115 */
1116 m = get_next_mapping(pool);
1117 m->tc = tc;
1118 m->pass_discard = pool->pf.discard_passdown;
1119 m->definitely_not_shared = !lookup_result.shared;
1120 m->virt_block = block;
1121 m->data_block = lookup_result.block;
1122 m->cell = cell;
1123 m->cell2 = cell2;
1124 m->bio = bio;
1125
1126 if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
1127 spin_lock_irqsave(&pool->lock, flags);
1128 list_add_tail(&m->list, &pool->prepared_discards);
1129 spin_unlock_irqrestore(&pool->lock, flags);
1130 wake_worker(pool);
1131 }
1132 } else {
1133 inc_all_io_entry(pool, bio);
1134 cell_defer_no_holder(tc, cell);
1135 cell_defer_no_holder(tc, cell2);
1136
1137 /*
1138 * The DM core makes sure that the discard doesn't span
1139 * a block boundary. So we submit the discard of a
1140 * partial block appropriately.
1141 */
1142 if ((!lookup_result.shared) && pool->pf.discard_passdown)
1143 remap_and_issue(tc, bio, lookup_result.block);
1144 else
1145 bio_endio(bio, 0);
1146 }
1147 break;
1148
1149 case -ENODATA:
1150 /*
1151 * It isn't provisioned, just forget it.
1152 */
1153 cell_defer_no_holder(tc, cell);
1154 bio_endio(bio, 0);
1155 break;
1156
1157 default:
1158 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1159 __func__, r);
1160 cell_defer_no_holder(tc, cell);
1161 bio_io_error(bio);
1162 break;
1163 }
1164}
1165
1166static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
1167 struct dm_cell_key *key,
1168 struct dm_thin_lookup_result *lookup_result,
1169 struct dm_bio_prison_cell *cell)
1170{
1171 int r;
1172 dm_block_t data_block;
1173 struct pool *pool = tc->pool;
1174
1175 r = alloc_data_block(tc, &data_block);
1176 switch (r) {
1177 case 0:
1178 schedule_internal_copy(tc, block, lookup_result->block,
1179 data_block, cell, bio);
1180 break;
1181
1182 case -ENOSPC:
1183 retry_bios_on_resume(pool, cell);
1184 break;
1185
1186 default:
1187 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1188 __func__, r);
1189 cell_error(pool, cell);
1190 break;
1191 }
1192}
1193
1194static void process_shared_bio(struct thin_c *tc, struct bio *bio,
1195 dm_block_t block,
1196 struct dm_thin_lookup_result *lookup_result)
1197{
1198 struct dm_bio_prison_cell *cell;
1199 struct pool *pool = tc->pool;
1200 struct dm_cell_key key;
1201
1202 /*
1203 * If cell is already occupied, then sharing is already in the process
1204 * of being broken so we have nothing further to do here.
1205 */
1206 build_data_key(tc->td, lookup_result->block, &key);
1207 if (bio_detain(pool, &key, bio, &cell))
1208 return;
1209
1210 if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size)
1211 break_sharing(tc, bio, block, &key, lookup_result, cell);
1212 else {
1213 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1214
1215 h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds);
1216 inc_all_io_entry(pool, bio);
1217 cell_defer_no_holder(tc, cell);
1218
1219 remap_and_issue(tc, bio, lookup_result->block);
1220 }
1221}
1222
1223static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
1224 struct dm_bio_prison_cell *cell)
1225{
1226 int r;
1227 dm_block_t data_block;
1228 struct pool *pool = tc->pool;
1229
1230 /*
1231 * Remap empty bios (flushes) immediately, without provisioning.
1232 */
1233 if (!bio->bi_iter.bi_size) {
1234 inc_all_io_entry(pool, bio);
1235 cell_defer_no_holder(tc, cell);
1236
1237 remap_and_issue(tc, bio, 0);
1238 return;
1239 }
1240
1241 /*
1242 * Fill read bios with zeroes and complete them immediately.
1243 */
1244 if (bio_data_dir(bio) == READ) {
1245 zero_fill_bio(bio);
1246 cell_defer_no_holder(tc, cell);
1247 bio_endio(bio, 0);
1248 return;
1249 }
1250
1251 r = alloc_data_block(tc, &data_block);
1252 switch (r) {
1253 case 0:
1254 if (tc->origin_dev)
1255 schedule_external_copy(tc, block, data_block, cell, bio);
1256 else
1257 schedule_zero(tc, block, data_block, cell, bio);
1258 break;
1259
1260 case -ENOSPC:
1261 retry_bios_on_resume(pool, cell);
1262 break;
1263
1264 default:
1265 DMERR_LIMIT("%s: alloc_data_block() failed: error = %d",
1266 __func__, r);
1267 cell_error(pool, cell);
1268 break;
1269 }
1270}
1271
1272static void process_bio(struct thin_c *tc, struct bio *bio)
1273{
1274 int r;
1275 struct pool *pool = tc->pool;
1276 dm_block_t block = get_bio_block(tc, bio);
1277 struct dm_bio_prison_cell *cell;
1278 struct dm_cell_key key;
1279 struct dm_thin_lookup_result lookup_result;
1280
1281 /*
1282 * If cell is already occupied, then the block is already
1283 * being provisioned so we have nothing further to do here.
1284 */
1285 build_virtual_key(tc->td, block, &key);
1286 if (bio_detain(pool, &key, bio, &cell))
1287 return;
1288
1289 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1290 switch (r) {
1291 case 0:
1292 if (lookup_result.shared) {
1293 process_shared_bio(tc, bio, block, &lookup_result);
1294 cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */
1295 } else {
1296 inc_all_io_entry(pool, bio);
1297 cell_defer_no_holder(tc, cell);
1298
1299 remap_and_issue(tc, bio, lookup_result.block);
1300 }
1301 break;
1302
1303 case -ENODATA:
1304 if (bio_data_dir(bio) == READ && tc->origin_dev) {
1305 inc_all_io_entry(pool, bio);
1306 cell_defer_no_holder(tc, cell);
1307
1308 remap_to_origin_and_issue(tc, bio);
1309 } else
1310 provision_block(tc, bio, block, cell);
1311 break;
1312
1313 default:
1314 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1315 __func__, r);
1316 cell_defer_no_holder(tc, cell);
1317 bio_io_error(bio);
1318 break;
1319 }
1320}
1321
1322static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
1323{
1324 int r;
1325 int rw = bio_data_dir(bio);
1326 dm_block_t block = get_bio_block(tc, bio);
1327 struct dm_thin_lookup_result lookup_result;
1328
1329 r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
1330 switch (r) {
1331 case 0:
1332 if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size)
1333 handle_unserviceable_bio(tc->pool, bio);
1334 else {
1335 inc_all_io_entry(tc->pool, bio);
1336 remap_and_issue(tc, bio, lookup_result.block);
1337 }
1338 break;
1339
1340 case -ENODATA:
1341 if (rw != READ) {
1342 handle_unserviceable_bio(tc->pool, bio);
1343 break;
1344 }
1345
1346 if (tc->origin_dev) {
1347 inc_all_io_entry(tc->pool, bio);
1348 remap_to_origin_and_issue(tc, bio);
1349 break;
1350 }
1351
1352 zero_fill_bio(bio);
1353 bio_endio(bio, 0);
1354 break;
1355
1356 default:
1357 DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d",
1358 __func__, r);
1359 bio_io_error(bio);
1360 break;
1361 }
1362}
1363
1364static void process_bio_success(struct thin_c *tc, struct bio *bio)
1365{
1366 bio_endio(bio, 0);
1367}
1368
1369static void process_bio_fail(struct thin_c *tc, struct bio *bio)
1370{
1371 bio_io_error(bio);
1372}
1373
1374/*
1375 * FIXME: should we also commit due to size of transaction, measured in
1376 * metadata blocks?
1377 */
1378static int need_commit_due_to_time(struct pool *pool)
1379{
1380 return jiffies < pool->last_commit_jiffies ||
1381 jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
1382}
1383
1384#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
1385#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
1386
1387static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
1388{
1389 struct rb_node **rbp, *parent;
1390 struct dm_thin_endio_hook *pbd;
1391 sector_t bi_sector = bio->bi_iter.bi_sector;
1392
1393 rbp = &tc->sort_bio_list.rb_node;
1394 parent = NULL;
1395 while (*rbp) {
1396 parent = *rbp;
1397 pbd = thin_pbd(parent);
1398
1399 if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
1400 rbp = &(*rbp)->rb_left;
1401 else
1402 rbp = &(*rbp)->rb_right;
1403 }
1404
1405 pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1406 rb_link_node(&pbd->rb_node, parent, rbp);
1407 rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
1408}
1409
1410static void __extract_sorted_bios(struct thin_c *tc)
1411{
1412 struct rb_node *node;
1413 struct dm_thin_endio_hook *pbd;
1414 struct bio *bio;
1415
1416 for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
1417 pbd = thin_pbd(node);
1418 bio = thin_bio(pbd);
1419
1420 bio_list_add(&tc->deferred_bio_list, bio);
1421 rb_erase(&pbd->rb_node, &tc->sort_bio_list);
1422 }
1423
1424 WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
1425}
1426
1427static void __sort_thin_deferred_bios(struct thin_c *tc)
1428{
1429 struct bio *bio;
1430 struct bio_list bios;
1431
1432 bio_list_init(&bios);
1433 bio_list_merge(&bios, &tc->deferred_bio_list);
1434 bio_list_init(&tc->deferred_bio_list);
1435
1436 /* Sort deferred_bio_list using rb-tree */
1437 while ((bio = bio_list_pop(&bios)))
1438 __thin_bio_rb_add(tc, bio);
1439
1440 /*
1441 * Transfer the sorted bios in sort_bio_list back to
1442 * deferred_bio_list to allow lockless submission of
1443 * all bios.
1444 */
1445 __extract_sorted_bios(tc);
1446}
1447
1448static void process_thin_deferred_bios(struct thin_c *tc)
1449{
1450 struct pool *pool = tc->pool;
1451 unsigned long flags;
1452 struct bio *bio;
1453 struct bio_list bios;
1454 struct blk_plug plug;
1455
1456 if (tc->requeue_mode) {
1457 requeue_bio_list(tc, &tc->deferred_bio_list);
1458 return;
1459 }
1460
1461 bio_list_init(&bios);
1462
1463 spin_lock_irqsave(&tc->lock, flags);
1464
1465 if (bio_list_empty(&tc->deferred_bio_list)) {
1466 spin_unlock_irqrestore(&tc->lock, flags);
1467 return;
1468 }
1469
1470 __sort_thin_deferred_bios(tc);
1471
1472 bio_list_merge(&bios, &tc->deferred_bio_list);
1473 bio_list_init(&tc->deferred_bio_list);
1474
1475 spin_unlock_irqrestore(&tc->lock, flags);
1476
1477 blk_start_plug(&plug);
1478 while ((bio = bio_list_pop(&bios))) {
1479 /*
1480 * If we've got no free new_mapping structs, and processing
1481 * this bio might require one, we pause until there are some
1482 * prepared mappings to process.
1483 */
1484 if (ensure_next_mapping(pool)) {
1485 spin_lock_irqsave(&tc->lock, flags);
1486 bio_list_add(&tc->deferred_bio_list, bio);
1487 bio_list_merge(&tc->deferred_bio_list, &bios);
1488 spin_unlock_irqrestore(&tc->lock, flags);
1489 break;
1490 }
1491
1492 if (bio->bi_rw & REQ_DISCARD)
1493 pool->process_discard(tc, bio);
1494 else
1495 pool->process_bio(tc, bio);
1496 }
1497 blk_finish_plug(&plug);
1498}
1499
1500static void thin_get(struct thin_c *tc);
1501static void thin_put(struct thin_c *tc);
1502
1503/*
1504 * We can't hold rcu_read_lock() around code that can block. So we
1505 * find a thin with the rcu lock held; bump a refcount; then drop
1506 * the lock.
1507 */
1508static struct thin_c *get_first_thin(struct pool *pool)
1509{
1510 struct thin_c *tc = NULL;
1511
1512 rcu_read_lock();
1513 if (!list_empty(&pool->active_thins)) {
1514 tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
1515 thin_get(tc);
1516 }
1517 rcu_read_unlock();
1518
1519 return tc;
1520}
1521
1522static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
1523{
1524 struct thin_c *old_tc = tc;
1525
1526 rcu_read_lock();
1527 list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
1528 thin_get(tc);
1529 thin_put(old_tc);
1530 rcu_read_unlock();
1531 return tc;
1532 }
1533 thin_put(old_tc);
1534 rcu_read_unlock();
1535
1536 return NULL;
1537}
1538
1539static void process_deferred_bios(struct pool *pool)
1540{
1541 unsigned long flags;
1542 struct bio *bio;
1543 struct bio_list bios;
1544 struct thin_c *tc;
1545
1546 tc = get_first_thin(pool);
1547 while (tc) {
1548 process_thin_deferred_bios(tc);
1549 tc = get_next_thin(pool, tc);
1550 }
1551
1552 /*
1553 * If there are any deferred flush bios, we must commit
1554 * the metadata before issuing them.
1555 */
1556 bio_list_init(&bios);
1557 spin_lock_irqsave(&pool->lock, flags);
1558 bio_list_merge(&bios, &pool->deferred_flush_bios);
1559 bio_list_init(&pool->deferred_flush_bios);
1560 spin_unlock_irqrestore(&pool->lock, flags);
1561
1562 if (bio_list_empty(&bios) &&
1563 !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
1564 return;
1565
1566 if (commit(pool)) {
1567 while ((bio = bio_list_pop(&bios)))
1568 bio_io_error(bio);
1569 return;
1570 }
1571 pool->last_commit_jiffies = jiffies;
1572
1573 while ((bio = bio_list_pop(&bios)))
1574 generic_make_request(bio);
1575}
1576
1577static void do_worker(struct work_struct *ws)
1578{
1579 struct pool *pool = container_of(ws, struct pool, worker);
1580
1581 process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
1582 process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
1583 process_deferred_bios(pool);
1584}
1585
1586/*
1587 * We want to commit periodically so that not too much
1588 * unwritten data builds up.
1589 */
1590static void do_waker(struct work_struct *ws)
1591{
1592 struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker);
1593 wake_worker(pool);
1594 queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
1595}
1596
1597/*
1598 * We're holding onto IO to allow userland time to react. After the
1599 * timeout either the pool will have been resized (and thus back in
1600 * PM_WRITE mode), or we degrade to PM_READ_ONLY and start erroring IO.
1601 */
1602static void do_no_space_timeout(struct work_struct *ws)
1603{
1604 struct pool *pool = container_of(to_delayed_work(ws), struct pool,
1605 no_space_timeout);
1606
1607 if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space)
1608 set_pool_mode(pool, PM_READ_ONLY);
1609}
1610
1611/*----------------------------------------------------------------*/
1612
1613struct noflush_work {
1614 struct work_struct worker;
1615 struct thin_c *tc;
1616
1617 atomic_t complete;
1618 wait_queue_head_t wait;
1619};
1620
1621static void complete_noflush_work(struct noflush_work *w)
1622{
1623 atomic_set(&w->complete, 1);
1624 wake_up(&w->wait);
1625}
1626
1627static void do_noflush_start(struct work_struct *ws)
1628{
1629 struct noflush_work *w = container_of(ws, struct noflush_work, worker);
1630 w->tc->requeue_mode = true;
1631 requeue_io(w->tc);
1632 complete_noflush_work(w);
1633}
1634
1635static void do_noflush_stop(struct work_struct *ws)
1636{
1637 struct noflush_work *w = container_of(ws, struct noflush_work, worker);
1638 w->tc->requeue_mode = false;
1639 complete_noflush_work(w);
1640}
1641
1642static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
1643{
1644 struct noflush_work w;
1645
1646 INIT_WORK_ONSTACK(&w.worker, fn);
1647 w.tc = tc;
1648 atomic_set(&w.complete, 0);
1649 init_waitqueue_head(&w.wait);
1650
1651 queue_work(tc->pool->wq, &w.worker);
1652
1653 wait_event(w.wait, atomic_read(&w.complete));
1654}
1655
1656/*----------------------------------------------------------------*/
1657
1658static enum pool_mode get_pool_mode(struct pool *pool)
1659{
1660 return pool->pf.mode;
1661}
1662
1663static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
1664{
1665 dm_table_event(pool->ti->table);
1666 DMINFO("%s: switching pool to %s mode",
1667 dm_device_name(pool->pool_md), new_mode);
1668}
1669
1670static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
1671{
1672 struct pool_c *pt = pool->ti->private;
1673 bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
1674 enum pool_mode old_mode = get_pool_mode(pool);
1675 unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
1676
1677 /*
1678 * Never allow the pool to transition to PM_WRITE mode if user
1679 * intervention is required to verify metadata and data consistency.
1680 */
1681 if (new_mode == PM_WRITE && needs_check) {
1682 DMERR("%s: unable to switch pool to write mode until repaired.",
1683 dm_device_name(pool->pool_md));
1684 if (old_mode != new_mode)
1685 new_mode = old_mode;
1686 else
1687 new_mode = PM_READ_ONLY;
1688 }
1689 /*
1690 * If we were in PM_FAIL mode, rollback of metadata failed. We're
1691 * not going to recover without a thin_repair. So we never let the
1692 * pool move out of the old mode.
1693 */
1694 if (old_mode == PM_FAIL)
1695 new_mode = old_mode;
1696
1697 switch (new_mode) {
1698 case PM_FAIL:
1699 if (old_mode != new_mode)
1700 notify_of_pool_mode_change(pool, "failure");
1701 dm_pool_metadata_read_only(pool->pmd);
1702 pool->process_bio = process_bio_fail;
1703 pool->process_discard = process_bio_fail;
1704 pool->process_prepared_mapping = process_prepared_mapping_fail;
1705 pool->process_prepared_discard = process_prepared_discard_fail;
1706
1707 error_retry_list(pool);
1708 break;
1709
1710 case PM_READ_ONLY:
1711 if (old_mode != new_mode)
1712 notify_of_pool_mode_change(pool, "read-only");
1713 dm_pool_metadata_read_only(pool->pmd);
1714 pool->process_bio = process_bio_read_only;
1715 pool->process_discard = process_bio_success;
1716 pool->process_prepared_mapping = process_prepared_mapping_fail;
1717 pool->process_prepared_discard = process_prepared_discard_passdown;
1718
1719 error_retry_list(pool);
1720 break;
1721
1722 case PM_OUT_OF_DATA_SPACE:
1723 /*
1724 * Ideally we'd never hit this state; the low water mark
1725 * would trigger userland to extend the pool before we
1726 * completely run out of data space. However, many small
1727 * IOs to unprovisioned space can consume data space at an
1728 * alarming rate. Adjust your low water mark if you're
1729 * frequently seeing this mode.
1730 */
1731 if (old_mode != new_mode)
1732 notify_of_pool_mode_change(pool, "out-of-data-space");
1733 pool->process_bio = process_bio_read_only;
1734 pool->process_discard = process_discard;
1735 pool->process_prepared_mapping = process_prepared_mapping;
1736 pool->process_prepared_discard = process_prepared_discard_passdown;
1737
1738 if (!pool->pf.error_if_no_space && no_space_timeout)
1739 queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
1740 break;
1741
1742 case PM_WRITE:
1743 if (old_mode != new_mode)
1744 notify_of_pool_mode_change(pool, "write");
1745 dm_pool_metadata_read_write(pool->pmd);
1746 pool->process_bio = process_bio;
1747 pool->process_discard = process_discard;
1748 pool->process_prepared_mapping = process_prepared_mapping;
1749 pool->process_prepared_discard = process_prepared_discard;
1750 break;
1751 }
1752
1753 pool->pf.mode = new_mode;
1754 /*
1755 * The pool mode may have changed, sync it so bind_control_target()
1756 * doesn't cause an unexpected mode transition on resume.
1757 */
1758 pt->adjusted_pf.mode = new_mode;
1759}
1760
1761static void abort_transaction(struct pool *pool)
1762{
1763 const char *dev_name = dm_device_name(pool->pool_md);
1764
1765 DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
1766 if (dm_pool_abort_metadata(pool->pmd)) {
1767 DMERR("%s: failed to abort metadata transaction", dev_name);
1768 set_pool_mode(pool, PM_FAIL);
1769 }
1770
1771 if (dm_pool_metadata_set_needs_check(pool->pmd)) {
1772 DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
1773 set_pool_mode(pool, PM_FAIL);
1774 }
1775}
1776
1777static void metadata_operation_failed(struct pool *pool, const char *op, int r)
1778{
1779 DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
1780 dm_device_name(pool->pool_md), op, r);
1781
1782 abort_transaction(pool);
1783 set_pool_mode(pool, PM_READ_ONLY);
1784}
1785
1786/*----------------------------------------------------------------*/
1787
1788/*
1789 * Mapping functions.
1790 */
1791
1792/*
1793 * Called only while mapping a thin bio to hand it over to the workqueue.
1794 */
1795static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
1796{
1797 unsigned long flags;
1798 struct pool *pool = tc->pool;
1799
1800 spin_lock_irqsave(&tc->lock, flags);
1801 bio_list_add(&tc->deferred_bio_list, bio);
1802 spin_unlock_irqrestore(&tc->lock, flags);
1803
1804 wake_worker(pool);
1805}
1806
1807static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
1808{
1809 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
1810
1811 h->tc = tc;
1812 h->shared_read_entry = NULL;
1813 h->all_io_entry = NULL;
1814 h->overwrite_mapping = NULL;
1815}
1816
1817/*
1818 * Non-blocking function called from the thin target's map function.
1819 */
1820static int thin_bio_map(struct dm_target *ti, struct bio *bio)
1821{
1822 int r;
1823 struct thin_c *tc = ti->private;
1824 dm_block_t block = get_bio_block(tc, bio);
1825 struct dm_thin_device *td = tc->td;
1826 struct dm_thin_lookup_result result;
1827 struct dm_bio_prison_cell cell1, cell2;
1828 struct dm_bio_prison_cell *cell_result;
1829 struct dm_cell_key key;
1830
1831 thin_hook_bio(tc, bio);
1832
1833 if (tc->requeue_mode) {
1834 bio_endio(bio, DM_ENDIO_REQUEUE);
1835 return DM_MAPIO_SUBMITTED;
1836 }
1837
1838 if (get_pool_mode(tc->pool) == PM_FAIL) {
1839 bio_io_error(bio);
1840 return DM_MAPIO_SUBMITTED;
1841 }
1842
1843 if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
1844 thin_defer_bio(tc, bio);
1845 return DM_MAPIO_SUBMITTED;
1846 }
1847
1848 r = dm_thin_find_block(td, block, 0, &result);
1849
1850 /*
1851 * Note that we defer readahead too.
1852 */
1853 switch (r) {
1854 case 0:
1855 if (unlikely(result.shared)) {
1856 /*
1857 * We have a race condition here between the
1858 * result.shared value returned by the lookup and
1859 * snapshot creation, which may cause new
1860 * sharing.
1861 *
1862 * To avoid this always quiesce the origin before
1863 * taking the snap. You want to do this anyway to
1864 * ensure a consistent application view
1865 * (i.e. lockfs).
1866 *
1867 * More distant ancestors are irrelevant. The
1868 * shared flag will be set in their case.
1869 */
1870 thin_defer_bio(tc, bio);
1871 return DM_MAPIO_SUBMITTED;
1872 }
1873
1874 build_virtual_key(tc->td, block, &key);
1875 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
1876 return DM_MAPIO_SUBMITTED;
1877
1878 build_data_key(tc->td, result.block, &key);
1879 if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
1880 cell_defer_no_holder_no_free(tc, &cell1);
1881 return DM_MAPIO_SUBMITTED;
1882 }
1883
1884 inc_all_io_entry(tc->pool, bio);
1885 cell_defer_no_holder_no_free(tc, &cell2);
1886 cell_defer_no_holder_no_free(tc, &cell1);
1887
1888 remap(tc, bio, result.block);
1889 return DM_MAPIO_REMAPPED;
1890
1891 case -ENODATA:
1892 if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
1893 /*
1894 * This block isn't provisioned, and we have no way
1895 * of doing so.
1896 */
1897 handle_unserviceable_bio(tc->pool, bio);
1898 return DM_MAPIO_SUBMITTED;
1899 }
1900 /* fall through */
1901
1902 case -EWOULDBLOCK:
1903 /*
1904 * In future, the failed dm_thin_find_block above could
1905 * provide the hint to load the metadata into cache.
1906 */
1907 thin_defer_bio(tc, bio);
1908 return DM_MAPIO_SUBMITTED;
1909
1910 default:
1911 /*
1912 * Must always call bio_io_error on failure.
1913 * dm_thin_find_block can fail with -EINVAL if the
1914 * pool is switched to fail-io mode.
1915 */
1916 bio_io_error(bio);
1917 return DM_MAPIO_SUBMITTED;
1918 }
1919}
1920
1921static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
1922{
1923 struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
1924 struct request_queue *q;
1925
1926 if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
1927 return 1;
1928
1929 q = bdev_get_queue(pt->data_dev->bdev);
1930 return bdi_congested(&q->backing_dev_info, bdi_bits);
1931}
1932
1933static void requeue_bios(struct pool *pool)
1934{
1935 unsigned long flags;
1936 struct thin_c *tc;
1937
1938 rcu_read_lock();
1939 list_for_each_entry_rcu(tc, &pool->active_thins, list) {
1940 spin_lock_irqsave(&tc->lock, flags);
1941 bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
1942 bio_list_init(&tc->retry_on_resume_list);
1943 spin_unlock_irqrestore(&tc->lock, flags);
1944 }
1945 rcu_read_unlock();
1946}
1947
1948/*----------------------------------------------------------------
1949 * Binding of control targets to a pool object
1950 *--------------------------------------------------------------*/
1951static bool data_dev_supports_discard(struct pool_c *pt)
1952{
1953 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
1954
1955 return q && blk_queue_discard(q);
1956}
1957
1958static bool is_factor(sector_t block_size, uint32_t n)
1959{
1960 return !sector_div(block_size, n);
1961}
1962
1963/*
1964 * If discard_passdown was enabled verify that the data device
1965 * supports discards. Disable discard_passdown if not.
1966 */
1967static void disable_passdown_if_not_supported(struct pool_c *pt)
1968{
1969 struct pool *pool = pt->pool;
1970 struct block_device *data_bdev = pt->data_dev->bdev;
1971 struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits;
1972 sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
1973 const char *reason = NULL;
1974 char buf[BDEVNAME_SIZE];
1975
1976 if (!pt->adjusted_pf.discard_passdown)
1977 return;
1978
1979 if (!data_dev_supports_discard(pt))
1980 reason = "discard unsupported";
1981
1982 else if (data_limits->max_discard_sectors < pool->sectors_per_block)
1983 reason = "max discard sectors smaller than a block";
1984
1985 else if (data_limits->discard_granularity > block_size)
1986 reason = "discard granularity larger than a block";
1987
1988 else if (!is_factor(block_size, data_limits->discard_granularity))
1989 reason = "discard granularity not a factor of block size";
1990
1991 if (reason) {
1992 DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
1993 pt->adjusted_pf.discard_passdown = false;
1994 }
1995}
1996
1997static int bind_control_target(struct pool *pool, struct dm_target *ti)
1998{
1999 struct pool_c *pt = ti->private;
2000
2001 /*
2002 * We want to make sure that a pool in PM_FAIL mode is never upgraded.
2003 */
2004 enum pool_mode old_mode = get_pool_mode(pool);
2005 enum pool_mode new_mode = pt->adjusted_pf.mode;
2006
2007 /*
2008 * Don't change the pool's mode until set_pool_mode() below.
2009 * Otherwise the pool's process_* function pointers may
2010 * not match the desired pool mode.
2011 */
2012 pt->adjusted_pf.mode = old_mode;
2013
2014 pool->ti = ti;
2015 pool->pf = pt->adjusted_pf;
2016 pool->low_water_blocks = pt->low_water_blocks;
2017
2018 set_pool_mode(pool, new_mode);
2019
2020 return 0;
2021}
2022
2023static void unbind_control_target(struct pool *pool, struct dm_target *ti)
2024{
2025 if (pool->ti == ti)
2026 pool->ti = NULL;
2027}
2028
2029/*----------------------------------------------------------------
2030 * Pool creation
2031 *--------------------------------------------------------------*/
2032/* Initialize pool features. */
2033static void pool_features_init(struct pool_features *pf)
2034{
2035 pf->mode = PM_WRITE;
2036 pf->zero_new_blocks = true;
2037 pf->discard_enabled = true;
2038 pf->discard_passdown = true;
2039 pf->error_if_no_space = false;
2040}
2041
2042static void __pool_destroy(struct pool *pool)
2043{
2044 __pool_table_remove(pool);
2045
2046 if (dm_pool_metadata_close(pool->pmd) < 0)
2047 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2048
2049 dm_bio_prison_destroy(pool->prison);
2050 dm_kcopyd_client_destroy(pool->copier);
2051
2052 if (pool->wq)
2053 destroy_workqueue(pool->wq);
2054
2055 if (pool->next_mapping)
2056 mempool_free(pool->next_mapping, pool->mapping_pool);
2057 mempool_destroy(pool->mapping_pool);
2058 dm_deferred_set_destroy(pool->shared_read_ds);
2059 dm_deferred_set_destroy(pool->all_io_ds);
2060 kfree(pool);
2061}
2062
2063static struct kmem_cache *_new_mapping_cache;
2064
2065static struct pool *pool_create(struct mapped_device *pool_md,
2066 struct block_device *metadata_dev,
2067 unsigned long block_size,
2068 int read_only, char **error)
2069{
2070 int r;
2071 void *err_p;
2072 struct pool *pool;
2073 struct dm_pool_metadata *pmd;
2074 bool format_device = read_only ? false : true;
2075
2076 pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
2077 if (IS_ERR(pmd)) {
2078 *error = "Error creating metadata object";
2079 return (struct pool *)pmd;
2080 }
2081
2082 pool = kmalloc(sizeof(*pool), GFP_KERNEL);
2083 if (!pool) {
2084 *error = "Error allocating memory for pool";
2085 err_p = ERR_PTR(-ENOMEM);
2086 goto bad_pool;
2087 }
2088
2089 pool->pmd = pmd;
2090 pool->sectors_per_block = block_size;
2091 if (block_size & (block_size - 1))
2092 pool->sectors_per_block_shift = -1;
2093 else
2094 pool->sectors_per_block_shift = __ffs(block_size);
2095 pool->low_water_blocks = 0;
2096 pool_features_init(&pool->pf);
2097 pool->prison = dm_bio_prison_create(PRISON_CELLS);
2098 if (!pool->prison) {
2099 *error = "Error creating pool's bio prison";
2100 err_p = ERR_PTR(-ENOMEM);
2101 goto bad_prison;
2102 }
2103
2104 pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2105 if (IS_ERR(pool->copier)) {
2106 r = PTR_ERR(pool->copier);
2107 *error = "Error creating pool's kcopyd client";
2108 err_p = ERR_PTR(r);
2109 goto bad_kcopyd_client;
2110 }
2111
2112 /*
2113 * Create singlethreaded workqueue that will service all devices
2114 * that use this metadata.
2115 */
2116 pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
2117 if (!pool->wq) {
2118 *error = "Error creating pool's workqueue";
2119 err_p = ERR_PTR(-ENOMEM);
2120 goto bad_wq;
2121 }
2122
2123 INIT_WORK(&pool->worker, do_worker);
2124 INIT_DELAYED_WORK(&pool->waker, do_waker);
2125 INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
2126 spin_lock_init(&pool->lock);
2127 bio_list_init(&pool->deferred_flush_bios);
2128 INIT_LIST_HEAD(&pool->prepared_mappings);
2129 INIT_LIST_HEAD(&pool->prepared_discards);
2130 INIT_LIST_HEAD(&pool->active_thins);
2131 pool->low_water_triggered = false;
2132
2133 pool->shared_read_ds = dm_deferred_set_create();
2134 if (!pool->shared_read_ds) {
2135 *error = "Error creating pool's shared read deferred set";
2136 err_p = ERR_PTR(-ENOMEM);
2137 goto bad_shared_read_ds;
2138 }
2139
2140 pool->all_io_ds = dm_deferred_set_create();
2141 if (!pool->all_io_ds) {
2142 *error = "Error creating pool's all io deferred set";
2143 err_p = ERR_PTR(-ENOMEM);
2144 goto bad_all_io_ds;
2145 }
2146
2147 pool->next_mapping = NULL;
2148 pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
2149 _new_mapping_cache);
2150 if (!pool->mapping_pool) {
2151 *error = "Error creating pool's mapping mempool";
2152 err_p = ERR_PTR(-ENOMEM);
2153 goto bad_mapping_pool;
2154 }
2155
2156 pool->ref_count = 1;
2157 pool->last_commit_jiffies = jiffies;
2158 pool->pool_md = pool_md;
2159 pool->md_dev = metadata_dev;
2160 __pool_table_insert(pool);
2161
2162 return pool;
2163
2164bad_mapping_pool:
2165 dm_deferred_set_destroy(pool->all_io_ds);
2166bad_all_io_ds:
2167 dm_deferred_set_destroy(pool->shared_read_ds);
2168bad_shared_read_ds:
2169 destroy_workqueue(pool->wq);
2170bad_wq:
2171 dm_kcopyd_client_destroy(pool->copier);
2172bad_kcopyd_client:
2173 dm_bio_prison_destroy(pool->prison);
2174bad_prison:
2175 kfree(pool);
2176bad_pool:
2177 if (dm_pool_metadata_close(pmd))
2178 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
2179
2180 return err_p;
2181}
2182
2183static void __pool_inc(struct pool *pool)
2184{
2185 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2186 pool->ref_count++;
2187}
2188
2189static void __pool_dec(struct pool *pool)
2190{
2191 BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
2192 BUG_ON(!pool->ref_count);
2193 if (!--pool->ref_count)
2194 __pool_destroy(pool);
2195}
2196
2197static struct pool *__pool_find(struct mapped_device *pool_md,
2198 struct block_device *metadata_dev,
2199 unsigned long block_size, int read_only,
2200 char **error, int *created)
2201{
2202 struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
2203
2204 if (pool) {
2205 if (pool->pool_md != pool_md) {
2206 *error = "metadata device already in use by a pool";
2207 return ERR_PTR(-EBUSY);
2208 }
2209 __pool_inc(pool);
2210
2211 } else {
2212 pool = __pool_table_lookup(pool_md);
2213 if (pool) {
2214 if (pool->md_dev != metadata_dev) {
2215 *error = "different pool cannot replace a pool";
2216 return ERR_PTR(-EINVAL);
2217 }
2218 __pool_inc(pool);
2219
2220 } else {
2221 pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
2222 *created = 1;
2223 }
2224 }
2225
2226 return pool;
2227}
2228
2229/*----------------------------------------------------------------
2230 * Pool target methods
2231 *--------------------------------------------------------------*/
2232static void pool_dtr(struct dm_target *ti)
2233{
2234 struct pool_c *pt = ti->private;
2235
2236 mutex_lock(&dm_thin_pool_table.mutex);
2237
2238 unbind_control_target(pt->pool, ti);
2239 __pool_dec(pt->pool);
2240 dm_put_device(ti, pt->metadata_dev);
2241 dm_put_device(ti, pt->data_dev);
2242 kfree(pt);
2243
2244 mutex_unlock(&dm_thin_pool_table.mutex);
2245}
2246
2247static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
2248 struct dm_target *ti)
2249{
2250 int r;
2251 unsigned argc;
2252 const char *arg_name;
2253
2254 static struct dm_arg _args[] = {
2255 {0, 4, "Invalid number of pool feature arguments"},
2256 };
2257
2258 /*
2259 * No feature arguments supplied.
2260 */
2261 if (!as->argc)
2262 return 0;
2263
2264 r = dm_read_arg_group(_args, as, &argc, &ti->error);
2265 if (r)
2266 return -EINVAL;
2267
2268 while (argc && !r) {
2269 arg_name = dm_shift_arg(as);
2270 argc--;
2271
2272 if (!strcasecmp(arg_name, "skip_block_zeroing"))
2273 pf->zero_new_blocks = false;
2274
2275 else if (!strcasecmp(arg_name, "ignore_discard"))
2276 pf->discard_enabled = false;
2277
2278 else if (!strcasecmp(arg_name, "no_discard_passdown"))
2279 pf->discard_passdown = false;
2280
2281 else if (!strcasecmp(arg_name, "read_only"))
2282 pf->mode = PM_READ_ONLY;
2283
2284 else if (!strcasecmp(arg_name, "error_if_no_space"))
2285 pf->error_if_no_space = true;
2286
2287 else {
2288 ti->error = "Unrecognised pool feature requested";
2289 r = -EINVAL;
2290 break;
2291 }
2292 }
2293
2294 return r;
2295}
2296
2297static void metadata_low_callback(void *context)
2298{
2299 struct pool *pool = context;
2300
2301 DMWARN("%s: reached low water mark for metadata device: sending event.",
2302 dm_device_name(pool->pool_md));
2303
2304 dm_table_event(pool->ti->table);
2305}
2306
2307static sector_t get_dev_size(struct block_device *bdev)
2308{
2309 return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
2310}
2311
2312static void warn_if_metadata_device_too_big(struct block_device *bdev)
2313{
2314 sector_t metadata_dev_size = get_dev_size(bdev);
2315 char buffer[BDEVNAME_SIZE];
2316
2317 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
2318 DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
2319 bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
2320}
2321
2322static sector_t get_metadata_dev_size(struct block_device *bdev)
2323{
2324 sector_t metadata_dev_size = get_dev_size(bdev);
2325
2326 if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
2327 metadata_dev_size = THIN_METADATA_MAX_SECTORS;
2328
2329 return metadata_dev_size;
2330}
2331
2332static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
2333{
2334 sector_t metadata_dev_size = get_metadata_dev_size(bdev);
2335
2336 sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
2337
2338 return metadata_dev_size;
2339}
2340
2341/*
2342 * When a metadata threshold is crossed a dm event is triggered, and
2343 * userland should respond by growing the metadata device. We could let
2344 * userland set the threshold, like we do with the data threshold, but I'm
2345 * not sure they know enough to do this well.
2346 */
2347static dm_block_t calc_metadata_threshold(struct pool_c *pt)
2348{
2349 /*
2350 * 4M is ample for all ops with the possible exception of thin
2351 * device deletion which is harmless if it fails (just retry the
2352 * delete after you've grown the device).
2353 */
2354 dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
2355 return min((dm_block_t)1024ULL /* 4M */, quarter);
2356}
2357
2358/*
2359 * thin-pool <metadata dev> <data dev>
2360 * <data block size (sectors)>
2361 * <low water mark (blocks)>
2362 * [<#feature args> [<arg>]*]
2363 *
2364 * Optional feature arguments are:
2365 * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
2366 * ignore_discard: disable discard
2367 * no_discard_passdown: don't pass discards down to the data device
2368 * read_only: Don't allow any changes to be made to the pool metadata.
2369 * error_if_no_space: error IOs, instead of queueing, if no space.
2370 */
2371static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
2372{
2373 int r, pool_created = 0;
2374 struct pool_c *pt;
2375 struct pool *pool;
2376 struct pool_features pf;
2377 struct dm_arg_set as;
2378 struct dm_dev *data_dev;
2379 unsigned long block_size;
2380 dm_block_t low_water_blocks;
2381 struct dm_dev *metadata_dev;
2382 fmode_t metadata_mode;
2383
2384 /*
2385 * FIXME Remove validation from scope of lock.
2386 */
2387 mutex_lock(&dm_thin_pool_table.mutex);
2388
2389 if (argc < 4) {
2390 ti->error = "Invalid argument count";
2391 r = -EINVAL;
2392 goto out_unlock;
2393 }
2394
2395 as.argc = argc;
2396 as.argv = argv;
2397
2398 /*
2399 * Set default pool features.
2400 */
2401 pool_features_init(&pf);
2402
2403 dm_consume_args(&as, 4);
2404 r = parse_pool_features(&as, &pf, ti);
2405 if (r)
2406 goto out_unlock;
2407
2408 metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
2409 r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
2410 if (r) {
2411 ti->error = "Error opening metadata block device";
2412 goto out_unlock;
2413 }
2414 warn_if_metadata_device_too_big(metadata_dev->bdev);
2415
2416 r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
2417 if (r) {
2418 ti->error = "Error getting data device";
2419 goto out_metadata;
2420 }
2421
2422 if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
2423 block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
2424 block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
2425 block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
2426 ti->error = "Invalid block size";
2427 r = -EINVAL;
2428 goto out;
2429 }
2430
2431 if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
2432 ti->error = "Invalid low water mark";
2433 r = -EINVAL;
2434 goto out;
2435 }
2436
2437 pt = kzalloc(sizeof(*pt), GFP_KERNEL);
2438 if (!pt) {
2439 r = -ENOMEM;
2440 goto out;
2441 }
2442
2443 pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
2444 block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
2445 if (IS_ERR(pool)) {
2446 r = PTR_ERR(pool);
2447 goto out_free_pt;
2448 }
2449
2450 /*
2451 * 'pool_created' reflects whether this is the first table load.
2452 * Top level discard support is not allowed to be changed after
2453 * initial load. This would require a pool reload to trigger thin
2454 * device changes.
2455 */
2456 if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
2457 ti->error = "Discard support cannot be disabled once enabled";
2458 r = -EINVAL;
2459 goto out_flags_changed;
2460 }
2461
2462 pt->pool = pool;
2463 pt->ti = ti;
2464 pt->metadata_dev = metadata_dev;
2465 pt->data_dev = data_dev;
2466 pt->low_water_blocks = low_water_blocks;
2467 pt->adjusted_pf = pt->requested_pf = pf;
2468 ti->num_flush_bios = 1;
2469
2470 /*
2471 * Only need to enable discards if the pool should pass
2472 * them down to the data device. The thin device's discard
2473 * processing will cause mappings to be removed from the btree.
2474 */
2475 ti->discard_zeroes_data_unsupported = true;
2476 if (pf.discard_enabled && pf.discard_passdown) {
2477 ti->num_discard_bios = 1;
2478
2479 /*
2480 * Setting 'discards_supported' circumvents the normal
2481 * stacking of discard limits (this keeps the pool and
2482 * thin devices' discard limits consistent).
2483 */
2484 ti->discards_supported = true;
2485 }
2486 ti->private = pt;
2487
2488 r = dm_pool_register_metadata_threshold(pt->pool->pmd,
2489 calc_metadata_threshold(pt),
2490 metadata_low_callback,
2491 pool);
2492 if (r)
2493 goto out_free_pt;
2494
2495 pt->callbacks.congested_fn = pool_is_congested;
2496 dm_table_add_target_callbacks(ti->table, &pt->callbacks);
2497
2498 mutex_unlock(&dm_thin_pool_table.mutex);
2499
2500 return 0;
2501
2502out_flags_changed:
2503 __pool_dec(pool);
2504out_free_pt:
2505 kfree(pt);
2506out:
2507 dm_put_device(ti, data_dev);
2508out_metadata:
2509 dm_put_device(ti, metadata_dev);
2510out_unlock:
2511 mutex_unlock(&dm_thin_pool_table.mutex);
2512
2513 return r;
2514}
2515
2516static int pool_map(struct dm_target *ti, struct bio *bio)
2517{
2518 int r;
2519 struct pool_c *pt = ti->private;
2520 struct pool *pool = pt->pool;
2521 unsigned long flags;
2522
2523 /*
2524 * As this is a singleton target, ti->begin is always zero.
2525 */
2526 spin_lock_irqsave(&pool->lock, flags);
2527 bio->bi_bdev = pt->data_dev->bdev;
2528 r = DM_MAPIO_REMAPPED;
2529 spin_unlock_irqrestore(&pool->lock, flags);
2530
2531 return r;
2532}
2533
2534static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
2535{
2536 int r;
2537 struct pool_c *pt = ti->private;
2538 struct pool *pool = pt->pool;
2539 sector_t data_size = ti->len;
2540 dm_block_t sb_data_size;
2541
2542 *need_commit = false;
2543
2544 (void) sector_div(data_size, pool->sectors_per_block);
2545
2546 r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
2547 if (r) {
2548 DMERR("%s: failed to retrieve data device size",
2549 dm_device_name(pool->pool_md));
2550 return r;
2551 }
2552
2553 if (data_size < sb_data_size) {
2554 DMERR("%s: pool target (%llu blocks) too small: expected %llu",
2555 dm_device_name(pool->pool_md),
2556 (unsigned long long)data_size, sb_data_size);
2557 return -EINVAL;
2558
2559 } else if (data_size > sb_data_size) {
2560 if (dm_pool_metadata_needs_check(pool->pmd)) {
2561 DMERR("%s: unable to grow the data device until repaired.",
2562 dm_device_name(pool->pool_md));
2563 return 0;
2564 }
2565
2566 if (sb_data_size)
2567 DMINFO("%s: growing the data device from %llu to %llu blocks",
2568 dm_device_name(pool->pool_md),
2569 sb_data_size, (unsigned long long)data_size);
2570 r = dm_pool_resize_data_dev(pool->pmd, data_size);
2571 if (r) {
2572 metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
2573 return r;
2574 }
2575
2576 *need_commit = true;
2577 }
2578
2579 return 0;
2580}
2581
2582static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
2583{
2584 int r;
2585 struct pool_c *pt = ti->private;
2586 struct pool *pool = pt->pool;
2587 dm_block_t metadata_dev_size, sb_metadata_dev_size;
2588
2589 *need_commit = false;
2590
2591 metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
2592
2593 r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
2594 if (r) {
2595 DMERR("%s: failed to retrieve metadata device size",
2596 dm_device_name(pool->pool_md));
2597 return r;
2598 }
2599
2600 if (metadata_dev_size < sb_metadata_dev_size) {
2601 DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
2602 dm_device_name(pool->pool_md),
2603 metadata_dev_size, sb_metadata_dev_size);
2604 return -EINVAL;
2605
2606 } else if (metadata_dev_size > sb_metadata_dev_size) {
2607 if (dm_pool_metadata_needs_check(pool->pmd)) {
2608 DMERR("%s: unable to grow the metadata device until repaired.",
2609 dm_device_name(pool->pool_md));
2610 return 0;
2611 }
2612
2613 warn_if_metadata_device_too_big(pool->md_dev);
2614 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
2615 dm_device_name(pool->pool_md),
2616 sb_metadata_dev_size, metadata_dev_size);
2617 r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
2618 if (r) {
2619 metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
2620 return r;
2621 }
2622
2623 *need_commit = true;
2624 }
2625
2626 return 0;
2627}
2628
2629/*
2630 * Retrieves the number of blocks of the data device from
2631 * the superblock and compares it to the actual device size,
2632 * thus resizing the data device in case it has grown.
2633 *
2634 * This both copes with opening preallocated data devices in the ctr
2635 * being followed by a resume
2636 * -and-
2637 * calling the resume method individually after userspace has
2638 * grown the data device in reaction to a table event.
2639 */
2640static int pool_preresume(struct dm_target *ti)
2641{
2642 int r;
2643 bool need_commit1, need_commit2;
2644 struct pool_c *pt = ti->private;
2645 struct pool *pool = pt->pool;
2646
2647 /*
2648 * Take control of the pool object.
2649 */
2650 r = bind_control_target(pool, ti);
2651 if (r)
2652 return r;
2653
2654 r = maybe_resize_data_dev(ti, &need_commit1);
2655 if (r)
2656 return r;
2657
2658 r = maybe_resize_metadata_dev(ti, &need_commit2);
2659 if (r)
2660 return r;
2661
2662 if (need_commit1 || need_commit2)
2663 (void) commit(pool);
2664
2665 return 0;
2666}
2667
2668static void pool_resume(struct dm_target *ti)
2669{
2670 struct pool_c *pt = ti->private;
2671 struct pool *pool = pt->pool;
2672 unsigned long flags;
2673
2674 spin_lock_irqsave(&pool->lock, flags);
2675 pool->low_water_triggered = false;
2676 spin_unlock_irqrestore(&pool->lock, flags);
2677 requeue_bios(pool);
2678
2679 do_waker(&pool->waker.work);
2680}
2681
2682static void pool_postsuspend(struct dm_target *ti)
2683{
2684 struct pool_c *pt = ti->private;
2685 struct pool *pool = pt->pool;
2686
2687 cancel_delayed_work(&pool->waker);
2688 cancel_delayed_work(&pool->no_space_timeout);
2689 flush_workqueue(pool->wq);
2690 (void) commit(pool);
2691}
2692
2693static int check_arg_count(unsigned argc, unsigned args_required)
2694{
2695 if (argc != args_required) {
2696 DMWARN("Message received with %u arguments instead of %u.",
2697 argc, args_required);
2698 return -EINVAL;
2699 }
2700
2701 return 0;
2702}
2703
2704static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
2705{
2706 if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
2707 *dev_id <= MAX_DEV_ID)
2708 return 0;
2709
2710 if (warning)
2711 DMWARN("Message received with invalid device id: %s", arg);
2712
2713 return -EINVAL;
2714}
2715
2716static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
2717{
2718 dm_thin_id dev_id;
2719 int r;
2720
2721 r = check_arg_count(argc, 2);
2722 if (r)
2723 return r;
2724
2725 r = read_dev_id(argv[1], &dev_id, 1);
2726 if (r)
2727 return r;
2728
2729 r = dm_pool_create_thin(pool->pmd, dev_id);
2730 if (r) {
2731 DMWARN("Creation of new thinly-provisioned device with id %s failed.",
2732 argv[1]);
2733 return r;
2734 }
2735
2736 return 0;
2737}
2738
2739static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2740{
2741 dm_thin_id dev_id;
2742 dm_thin_id origin_dev_id;
2743 int r;
2744
2745 r = check_arg_count(argc, 3);
2746 if (r)
2747 return r;
2748
2749 r = read_dev_id(argv[1], &dev_id, 1);
2750 if (r)
2751 return r;
2752
2753 r = read_dev_id(argv[2], &origin_dev_id, 1);
2754 if (r)
2755 return r;
2756
2757 r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
2758 if (r) {
2759 DMWARN("Creation of new snapshot %s of device %s failed.",
2760 argv[1], argv[2]);
2761 return r;
2762 }
2763
2764 return 0;
2765}
2766
2767static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
2768{
2769 dm_thin_id dev_id;
2770 int r;
2771
2772 r = check_arg_count(argc, 2);
2773 if (r)
2774 return r;
2775
2776 r = read_dev_id(argv[1], &dev_id, 1);
2777 if (r)
2778 return r;
2779
2780 r = dm_pool_delete_thin_device(pool->pmd, dev_id);
2781 if (r)
2782 DMWARN("Deletion of thin device %s failed.", argv[1]);
2783
2784 return r;
2785}
2786
2787static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
2788{
2789 dm_thin_id old_id, new_id;
2790 int r;
2791
2792 r = check_arg_count(argc, 3);
2793 if (r)
2794 return r;
2795
2796 if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
2797 DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
2798 return -EINVAL;
2799 }
2800
2801 if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
2802 DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
2803 return -EINVAL;
2804 }
2805
2806 r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
2807 if (r) {
2808 DMWARN("Failed to change transaction id from %s to %s.",
2809 argv[1], argv[2]);
2810 return r;
2811 }
2812
2813 return 0;
2814}
2815
2816static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2817{
2818 int r;
2819
2820 r = check_arg_count(argc, 1);
2821 if (r)
2822 return r;
2823
2824 (void) commit(pool);
2825
2826 r = dm_pool_reserve_metadata_snap(pool->pmd);
2827 if (r)
2828 DMWARN("reserve_metadata_snap message failed.");
2829
2830 return r;
2831}
2832
2833static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
2834{
2835 int r;
2836
2837 r = check_arg_count(argc, 1);
2838 if (r)
2839 return r;
2840
2841 r = dm_pool_release_metadata_snap(pool->pmd);
2842 if (r)
2843 DMWARN("release_metadata_snap message failed.");
2844
2845 return r;
2846}
2847
2848/*
2849 * Messages supported:
2850 * create_thin <dev_id>
2851 * create_snap <dev_id> <origin_id>
2852 * delete <dev_id>
2853 * trim <dev_id> <new_size_in_sectors>
2854 * set_transaction_id <current_trans_id> <new_trans_id>
2855 * reserve_metadata_snap
2856 * release_metadata_snap
2857 */
2858static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
2859{
2860 int r = -EINVAL;
2861 struct pool_c *pt = ti->private;
2862 struct pool *pool = pt->pool;
2863
2864 if (!strcasecmp(argv[0], "create_thin"))
2865 r = process_create_thin_mesg(argc, argv, pool);
2866
2867 else if (!strcasecmp(argv[0], "create_snap"))
2868 r = process_create_snap_mesg(argc, argv, pool);
2869
2870 else if (!strcasecmp(argv[0], "delete"))
2871 r = process_delete_mesg(argc, argv, pool);
2872
2873 else if (!strcasecmp(argv[0], "set_transaction_id"))
2874 r = process_set_transaction_id_mesg(argc, argv, pool);
2875
2876 else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
2877 r = process_reserve_metadata_snap_mesg(argc, argv, pool);
2878
2879 else if (!strcasecmp(argv[0], "release_metadata_snap"))
2880 r = process_release_metadata_snap_mesg(argc, argv, pool);
2881
2882 else
2883 DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
2884
2885 if (!r)
2886 (void) commit(pool);
2887
2888 return r;
2889}
2890
2891static void emit_flags(struct pool_features *pf, char *result,
2892 unsigned sz, unsigned maxlen)
2893{
2894 unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
2895 !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
2896 pf->error_if_no_space;
2897 DMEMIT("%u ", count);
2898
2899 if (!pf->zero_new_blocks)
2900 DMEMIT("skip_block_zeroing ");
2901
2902 if (!pf->discard_enabled)
2903 DMEMIT("ignore_discard ");
2904
2905 if (!pf->discard_passdown)
2906 DMEMIT("no_discard_passdown ");
2907
2908 if (pf->mode == PM_READ_ONLY)
2909 DMEMIT("read_only ");
2910
2911 if (pf->error_if_no_space)
2912 DMEMIT("error_if_no_space ");
2913}
2914
2915/*
2916 * Status line is:
2917 * <transaction id> <used metadata sectors>/<total metadata sectors>
2918 * <used data sectors>/<total data sectors> <held metadata root>
2919 */
2920static void pool_status(struct dm_target *ti, status_type_t type,
2921 unsigned status_flags, char *result, unsigned maxlen)
2922{
2923 int r;
2924 unsigned sz = 0;
2925 uint64_t transaction_id;
2926 dm_block_t nr_free_blocks_data;
2927 dm_block_t nr_free_blocks_metadata;
2928 dm_block_t nr_blocks_data;
2929 dm_block_t nr_blocks_metadata;
2930 dm_block_t held_root;
2931 char buf[BDEVNAME_SIZE];
2932 char buf2[BDEVNAME_SIZE];
2933 struct pool_c *pt = ti->private;
2934 struct pool *pool = pt->pool;
2935
2936 switch (type) {
2937 case STATUSTYPE_INFO:
2938 if (get_pool_mode(pool) == PM_FAIL) {
2939 DMEMIT("Fail");
2940 break;
2941 }
2942
2943 /* Commit to ensure statistics aren't out-of-date */
2944 if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
2945 (void) commit(pool);
2946
2947 r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
2948 if (r) {
2949 DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
2950 dm_device_name(pool->pool_md), r);
2951 goto err;
2952 }
2953
2954 r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
2955 if (r) {
2956 DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
2957 dm_device_name(pool->pool_md), r);
2958 goto err;
2959 }
2960
2961 r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
2962 if (r) {
2963 DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
2964 dm_device_name(pool->pool_md), r);
2965 goto err;
2966 }
2967
2968 r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
2969 if (r) {
2970 DMERR("%s: dm_pool_get_free_block_count returned %d",
2971 dm_device_name(pool->pool_md), r);
2972 goto err;
2973 }
2974
2975 r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
2976 if (r) {
2977 DMERR("%s: dm_pool_get_data_dev_size returned %d",
2978 dm_device_name(pool->pool_md), r);
2979 goto err;
2980 }
2981
2982 r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
2983 if (r) {
2984 DMERR("%s: dm_pool_get_metadata_snap returned %d",
2985 dm_device_name(pool->pool_md), r);
2986 goto err;
2987 }
2988
2989 DMEMIT("%llu %llu/%llu %llu/%llu ",
2990 (unsigned long long)transaction_id,
2991 (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
2992 (unsigned long long)nr_blocks_metadata,
2993 (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
2994 (unsigned long long)nr_blocks_data);
2995
2996 if (held_root)
2997 DMEMIT("%llu ", held_root);
2998 else
2999 DMEMIT("- ");
3000
3001 if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
3002 DMEMIT("out_of_data_space ");
3003 else if (pool->pf.mode == PM_READ_ONLY)
3004 DMEMIT("ro ");
3005 else
3006 DMEMIT("rw ");
3007
3008 if (!pool->pf.discard_enabled)
3009 DMEMIT("ignore_discard ");
3010 else if (pool->pf.discard_passdown)
3011 DMEMIT("discard_passdown ");
3012 else
3013 DMEMIT("no_discard_passdown ");
3014
3015 if (pool->pf.error_if_no_space)
3016 DMEMIT("error_if_no_space ");
3017 else
3018 DMEMIT("queue_if_no_space ");
3019
3020 break;
3021
3022 case STATUSTYPE_TABLE:
3023 DMEMIT("%s %s %lu %llu ",
3024 format_dev_t(buf, pt->metadata_dev->bdev->bd_dev),
3025 format_dev_t(buf2, pt->data_dev->bdev->bd_dev),
3026 (unsigned long)pool->sectors_per_block,
3027 (unsigned long long)pt->low_water_blocks);
3028 emit_flags(&pt->requested_pf, result, sz, maxlen);
3029 break;
3030 }
3031 return;
3032
3033err:
3034 DMEMIT("Error");
3035}
3036
3037static int pool_iterate_devices(struct dm_target *ti,
3038 iterate_devices_callout_fn fn, void *data)
3039{
3040 struct pool_c *pt = ti->private;
3041
3042 return fn(ti, pt->data_dev, 0, ti->len, data);
3043}
3044
3045static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
3046 struct bio_vec *biovec, int max_size)
3047{
3048 struct pool_c *pt = ti->private;
3049 struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
3050
3051 if (!q->merge_bvec_fn)
3052 return max_size;
3053
3054 bvm->bi_bdev = pt->data_dev->bdev;
3055
3056 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
3057}
3058
3059static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
3060{
3061 struct pool *pool = pt->pool;
3062 struct queue_limits *data_limits;
3063
3064 limits->max_discard_sectors = pool->sectors_per_block;
3065
3066 /*
3067 * discard_granularity is just a hint, and not enforced.
3068 */
3069 if (pt->adjusted_pf.discard_passdown) {
3070 data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
3071 limits->discard_granularity = data_limits->discard_granularity;
3072 } else
3073 limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
3074}
3075
3076static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
3077{
3078 struct pool_c *pt = ti->private;
3079 struct pool *pool = pt->pool;
3080 uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
3081
3082 /*
3083 * If the system-determined stacked limits are compatible with the
3084 * pool's blocksize (io_opt is a factor) do not override them.
3085 */
3086 if (io_opt_sectors < pool->sectors_per_block ||
3087 do_div(io_opt_sectors, pool->sectors_per_block)) {
3088 blk_limits_io_min(limits, 0);
3089 blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
3090 }
3091
3092 /*
3093 * pt->adjusted_pf is a staging area for the actual features to use.
3094 * They get transferred to the live pool in bind_control_target()
3095 * called from pool_preresume().
3096 */
3097 if (!pt->adjusted_pf.discard_enabled) {
3098 /*
3099 * Must explicitly disallow stacking discard limits otherwise the
3100 * block layer will stack them if pool's data device has support.
3101 * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the
3102 * user to see that, so make sure to set all discard limits to 0.
3103 */
3104 limits->discard_granularity = 0;
3105 return;
3106 }
3107
3108 disable_passdown_if_not_supported(pt);
3109
3110 set_discard_limits(pt, limits);
3111}
3112
3113static struct target_type pool_target = {
3114 .name = "thin-pool",
3115 .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
3116 DM_TARGET_IMMUTABLE,
3117 .version = {1, 12, 0},
3118 .module = THIS_MODULE,
3119 .ctr = pool_ctr,
3120 .dtr = pool_dtr,
3121 .map = pool_map,
3122 .postsuspend = pool_postsuspend,
3123 .preresume = pool_preresume,
3124 .resume = pool_resume,
3125 .message = pool_message,
3126 .status = pool_status,
3127 .merge = pool_merge,
3128 .iterate_devices = pool_iterate_devices,
3129 .io_hints = pool_io_hints,
3130};
3131
3132/*----------------------------------------------------------------
3133 * Thin target methods
3134 *--------------------------------------------------------------*/
3135static void thin_get(struct thin_c *tc)
3136{
3137 atomic_inc(&tc->refcount);
3138}
3139
3140static void thin_put(struct thin_c *tc)
3141{
3142 if (atomic_dec_and_test(&tc->refcount))
3143 complete(&tc->can_destroy);
3144}
3145
3146static void thin_dtr(struct dm_target *ti)
3147{
3148 struct thin_c *tc = ti->private;
3149 unsigned long flags;
3150
3151 thin_put(tc);
3152 wait_for_completion(&tc->can_destroy);
3153
3154 spin_lock_irqsave(&tc->pool->lock, flags);
3155 list_del_rcu(&tc->list);
3156 spin_unlock_irqrestore(&tc->pool->lock, flags);
3157 synchronize_rcu();
3158
3159 mutex_lock(&dm_thin_pool_table.mutex);
3160
3161 __pool_dec(tc->pool);
3162 dm_pool_close_thin_device(tc->td);
3163 dm_put_device(ti, tc->pool_dev);
3164 if (tc->origin_dev)
3165 dm_put_device(ti, tc->origin_dev);
3166 kfree(tc);
3167
3168 mutex_unlock(&dm_thin_pool_table.mutex);
3169}
3170
3171/*
3172 * Thin target parameters:
3173 *
3174 * <pool_dev> <dev_id> [origin_dev]
3175 *
3176 * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
3177 * dev_id: the internal device identifier
3178 * origin_dev: a device external to the pool that should act as the origin
3179 *
3180 * If the pool device has discards disabled, they get disabled for the thin
3181 * device as well.
3182 */
3183static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
3184{
3185 int r;
3186 struct thin_c *tc;
3187 struct dm_dev *pool_dev, *origin_dev;
3188 struct mapped_device *pool_md;
3189 unsigned long flags;
3190
3191 mutex_lock(&dm_thin_pool_table.mutex);
3192
3193 if (argc != 2 && argc != 3) {
3194 ti->error = "Invalid argument count";
3195 r = -EINVAL;
3196 goto out_unlock;
3197 }
3198
3199 tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
3200 if (!tc) {
3201 ti->error = "Out of memory";
3202 r = -ENOMEM;
3203 goto out_unlock;
3204 }
3205 spin_lock_init(&tc->lock);
3206 bio_list_init(&tc->deferred_bio_list);
3207 bio_list_init(&tc->retry_on_resume_list);
3208 tc->sort_bio_list = RB_ROOT;
3209
3210 if (argc == 3) {
3211 r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
3212 if (r) {
3213 ti->error = "Error opening origin device";
3214 goto bad_origin_dev;
3215 }
3216 tc->origin_dev = origin_dev;
3217 }
3218
3219 r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
3220 if (r) {
3221 ti->error = "Error opening pool device";
3222 goto bad_pool_dev;
3223 }
3224 tc->pool_dev = pool_dev;
3225
3226 if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
3227 ti->error = "Invalid device id";
3228 r = -EINVAL;
3229 goto bad_common;
3230 }
3231
3232 pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
3233 if (!pool_md) {
3234 ti->error = "Couldn't get pool mapped device";
3235 r = -EINVAL;
3236 goto bad_common;
3237 }
3238
3239 tc->pool = __pool_table_lookup(pool_md);
3240 if (!tc->pool) {
3241 ti->error = "Couldn't find pool object";
3242 r = -EINVAL;
3243 goto bad_pool_lookup;
3244 }
3245 __pool_inc(tc->pool);
3246
3247 if (get_pool_mode(tc->pool) == PM_FAIL) {
3248 ti->error = "Couldn't open thin device, Pool is in fail mode";
3249 r = -EINVAL;
3250 goto bad_thin_open;
3251 }
3252
3253 r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
3254 if (r) {
3255 ti->error = "Couldn't open thin internal device";
3256 goto bad_thin_open;
3257 }
3258
3259 r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
3260 if (r)
3261 goto bad_target_max_io_len;
3262
3263 ti->num_flush_bios = 1;
3264 ti->flush_supported = true;
3265 ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
3266
3267 /* In case the pool supports discards, pass them on. */
3268 ti->discard_zeroes_data_unsupported = true;
3269 if (tc->pool->pf.discard_enabled) {
3270 ti->discards_supported = true;
3271 ti->num_discard_bios = 1;
3272 /* Discard bios must be split on a block boundary */
3273 ti->split_discard_bios = true;
3274 }
3275
3276 dm_put(pool_md);
3277
3278 mutex_unlock(&dm_thin_pool_table.mutex);
3279
3280 atomic_set(&tc->refcount, 1);
3281 init_completion(&tc->can_destroy);
3282
3283 spin_lock_irqsave(&tc->pool->lock, flags);
3284 list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
3285 spin_unlock_irqrestore(&tc->pool->lock, flags);
3286 /*
3287 * This synchronize_rcu() call is needed here otherwise we risk a
3288 * wake_worker() call finding no bios to process (because the newly
3289 * added tc isn't yet visible). So this reduces latency since we
3290 * aren't then dependent on the periodic commit to wake_worker().
3291 */
3292 synchronize_rcu();
3293
3294 return 0;
3295
3296bad_target_max_io_len:
3297 dm_pool_close_thin_device(tc->td);
3298bad_thin_open:
3299 __pool_dec(tc->pool);
3300bad_pool_lookup:
3301 dm_put(pool_md);
3302bad_common:
3303 dm_put_device(ti, tc->pool_dev);
3304bad_pool_dev:
3305 if (tc->origin_dev)
3306 dm_put_device(ti, tc->origin_dev);
3307bad_origin_dev:
3308 kfree(tc);
3309out_unlock:
3310 mutex_unlock(&dm_thin_pool_table.mutex);
3311
3312 return r;
3313}
3314
3315static int thin_map(struct dm_target *ti, struct bio *bio)
3316{
3317 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
3318
3319 return thin_bio_map(ti, bio);
3320}
3321
3322static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
3323{
3324 unsigned long flags;
3325 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
3326 struct list_head work;
3327 struct dm_thin_new_mapping *m, *tmp;
3328 struct pool *pool = h->tc->pool;
3329
3330 if (h->shared_read_entry) {
3331 INIT_LIST_HEAD(&work);
3332 dm_deferred_entry_dec(h->shared_read_entry, &work);
3333
3334 spin_lock_irqsave(&pool->lock, flags);
3335 list_for_each_entry_safe(m, tmp, &work, list) {
3336 list_del(&m->list);
3337 m->quiesced = true;
3338 __maybe_add_mapping(m);
3339 }
3340 spin_unlock_irqrestore(&pool->lock, flags);
3341 }
3342
3343 if (h->all_io_entry) {
3344 INIT_LIST_HEAD(&work);
3345 dm_deferred_entry_dec(h->all_io_entry, &work);
3346 if (!list_empty(&work)) {
3347 spin_lock_irqsave(&pool->lock, flags);
3348 list_for_each_entry_safe(m, tmp, &work, list)
3349 list_add_tail(&m->list, &pool->prepared_discards);
3350 spin_unlock_irqrestore(&pool->lock, flags);
3351 wake_worker(pool);
3352 }
3353 }
3354
3355 return 0;
3356}
3357
3358static void thin_presuspend(struct dm_target *ti)
3359{
3360 struct thin_c *tc = ti->private;
3361
3362 if (dm_noflush_suspending(ti))
3363 noflush_work(tc, do_noflush_start);
3364}
3365
3366static void thin_postsuspend(struct dm_target *ti)
3367{
3368 struct thin_c *tc = ti->private;
3369
3370 /*
3371 * The dm_noflush_suspending flag has been cleared by now, so
3372 * unfortunately we must always run this.
3373 */
3374 noflush_work(tc, do_noflush_stop);
3375}
3376
3377/*
3378 * <nr mapped sectors> <highest mapped sector>
3379 */
3380static void thin_status(struct dm_target *ti, status_type_t type,
3381 unsigned status_flags, char *result, unsigned maxlen)
3382{
3383 int r;
3384 ssize_t sz = 0;
3385 dm_block_t mapped, highest;
3386 char buf[BDEVNAME_SIZE];
3387 struct thin_c *tc = ti->private;
3388
3389 if (get_pool_mode(tc->pool) == PM_FAIL) {
3390 DMEMIT("Fail");
3391 return;
3392 }
3393
3394 if (!tc->td)
3395 DMEMIT("-");
3396 else {
3397 switch (type) {
3398 case STATUSTYPE_INFO:
3399 r = dm_thin_get_mapped_count(tc->td, &mapped);
3400 if (r) {
3401 DMERR("dm_thin_get_mapped_count returned %d", r);
3402 goto err;
3403 }
3404
3405 r = dm_thin_get_highest_mapped_block(tc->td, &highest);
3406 if (r < 0) {
3407 DMERR("dm_thin_get_highest_mapped_block returned %d", r);
3408 goto err;
3409 }
3410
3411 DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
3412 if (r)
3413 DMEMIT("%llu", ((highest + 1) *
3414 tc->pool->sectors_per_block) - 1);
3415 else
3416 DMEMIT("-");
3417 break;
3418
3419 case STATUSTYPE_TABLE:
3420 DMEMIT("%s %lu",
3421 format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
3422 (unsigned long) tc->dev_id);
3423 if (tc->origin_dev)
3424 DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
3425 break;
3426 }
3427 }
3428
3429 return;
3430
3431err:
3432 DMEMIT("Error");
3433}
3434
3435static int thin_iterate_devices(struct dm_target *ti,
3436 iterate_devices_callout_fn fn, void *data)
3437{
3438 sector_t blocks;
3439 struct thin_c *tc = ti->private;
3440 struct pool *pool = tc->pool;
3441
3442 /*
3443 * We can't call dm_pool_get_data_dev_size() since that blocks. So
3444 * we follow a more convoluted path through to the pool's target.
3445 */
3446 if (!pool->ti)
3447 return 0; /* nothing is bound */
3448
3449 blocks = pool->ti->len;
3450 (void) sector_div(blocks, pool->sectors_per_block);
3451 if (blocks)
3452 return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data);
3453
3454 return 0;
3455}
3456
3457static struct target_type thin_target = {
3458 .name = "thin",
3459 .version = {1, 12, 0},
3460 .module = THIS_MODULE,
3461 .ctr = thin_ctr,
3462 .dtr = thin_dtr,
3463 .map = thin_map,
3464 .end_io = thin_endio,
3465 .presuspend = thin_presuspend,
3466 .postsuspend = thin_postsuspend,
3467 .status = thin_status,
3468 .iterate_devices = thin_iterate_devices,
3469};
3470
3471/*----------------------------------------------------------------*/
3472
3473static int __init dm_thin_init(void)
3474{
3475 int r;
3476
3477 pool_table_init();
3478
3479 r = dm_register_target(&thin_target);
3480 if (r)
3481 return r;
3482
3483 r = dm_register_target(&pool_target);
3484 if (r)
3485 goto bad_pool_target;
3486
3487 r = -ENOMEM;
3488
3489 _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
3490 if (!_new_mapping_cache)
3491 goto bad_new_mapping_cache;
3492
3493 return 0;
3494
3495bad_new_mapping_cache:
3496 dm_unregister_target(&pool_target);
3497bad_pool_target:
3498 dm_unregister_target(&thin_target);
3499
3500 return r;
3501}
3502
3503static void dm_thin_exit(void)
3504{
3505 dm_unregister_target(&thin_target);
3506 dm_unregister_target(&pool_target);
3507
3508 kmem_cache_destroy(_new_mapping_cache);
3509}
3510
3511module_init(dm_thin_init);
3512module_exit(dm_thin_exit);
3513
3514module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
3515MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
3516
3517MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
3518MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3519MODULE_LICENSE("GPL");