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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * bcache setup/teardown code, and some metadata io - read a superblock and
4 * figure out what to do with it.
5 *
6 * Copyright 2010, 2011 Kent Overstreet <[email protected]>
7 * Copyright 2012 Google, Inc.
8 */
9
10#include "bcache.h"
11#include "btree.h"
12#include "debug.h"
13#include "extents.h"
14#include "request.h"
15#include "writeback.h"
16#include "features.h"
17
18#include <linux/blkdev.h>
19#include <linux/pagemap.h>
20#include <linux/debugfs.h>
21#include <linux/idr.h>
22#include <linux/kthread.h>
23#include <linux/workqueue.h>
24#include <linux/module.h>
25#include <linux/random.h>
26#include <linux/reboot.h>
27#include <linux/sysfs.h>
28
29unsigned int bch_cutoff_writeback;
30unsigned int bch_cutoff_writeback_sync;
31
32static const char bcache_magic[] = {
33 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
34 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
35};
36
37static const char invalid_uuid[] = {
38 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
39 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
40};
41
42static struct kobject *bcache_kobj;
43struct mutex bch_register_lock;
44bool bcache_is_reboot;
45LIST_HEAD(bch_cache_sets);
46static LIST_HEAD(uncached_devices);
47
48static int bcache_major;
49static DEFINE_IDA(bcache_device_idx);
50static wait_queue_head_t unregister_wait;
51struct workqueue_struct *bcache_wq;
52struct workqueue_struct *bch_flush_wq;
53struct workqueue_struct *bch_journal_wq;
54
55
56#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
57/* limitation of partitions number on single bcache device */
58#define BCACHE_MINORS 128
59/* limitation of bcache devices number on single system */
60#define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
61
62/* Superblock */
63
64static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s)
65{
66 unsigned int bucket_size = le16_to_cpu(s->bucket_size);
67
68 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
69 if (bch_has_feature_large_bucket(sb)) {
70 unsigned int max, order;
71
72 max = sizeof(unsigned int) * BITS_PER_BYTE - 1;
73 order = le16_to_cpu(s->bucket_size);
74 /*
75 * bcache tool will make sure the overflow won't
76 * happen, an error message here is enough.
77 */
78 if (order > max)
79 pr_err("Bucket size (1 << %u) overflows\n",
80 order);
81 bucket_size = 1 << order;
82 } else if (bch_has_feature_obso_large_bucket(sb)) {
83 bucket_size +=
84 le16_to_cpu(s->obso_bucket_size_hi) << 16;
85 }
86 }
87
88 return bucket_size;
89}
90
91static const char *read_super_common(struct cache_sb *sb, struct block_device *bdev,
92 struct cache_sb_disk *s)
93{
94 const char *err;
95 unsigned int i;
96
97 sb->first_bucket= le16_to_cpu(s->first_bucket);
98 sb->nbuckets = le64_to_cpu(s->nbuckets);
99 sb->bucket_size = get_bucket_size(sb, s);
100
101 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
102 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
103
104 err = "Too many journal buckets";
105 if (sb->keys > SB_JOURNAL_BUCKETS)
106 goto err;
107
108 err = "Too many buckets";
109 if (sb->nbuckets > LONG_MAX)
110 goto err;
111
112 err = "Not enough buckets";
113 if (sb->nbuckets < 1 << 7)
114 goto err;
115
116 err = "Bad block size (not power of 2)";
117 if (!is_power_of_2(sb->block_size))
118 goto err;
119
120 err = "Bad block size (larger than page size)";
121 if (sb->block_size > PAGE_SECTORS)
122 goto err;
123
124 err = "Bad bucket size (not power of 2)";
125 if (!is_power_of_2(sb->bucket_size))
126 goto err;
127
128 err = "Bad bucket size (smaller than page size)";
129 if (sb->bucket_size < PAGE_SECTORS)
130 goto err;
131
132 err = "Invalid superblock: device too small";
133 if (get_capacity(bdev->bd_disk) <
134 sb->bucket_size * sb->nbuckets)
135 goto err;
136
137 err = "Bad UUID";
138 if (bch_is_zero(sb->set_uuid, 16))
139 goto err;
140
141 err = "Bad cache device number in set";
142 if (!sb->nr_in_set ||
143 sb->nr_in_set <= sb->nr_this_dev ||
144 sb->nr_in_set > MAX_CACHES_PER_SET)
145 goto err;
146
147 err = "Journal buckets not sequential";
148 for (i = 0; i < sb->keys; i++)
149 if (sb->d[i] != sb->first_bucket + i)
150 goto err;
151
152 err = "Too many journal buckets";
153 if (sb->first_bucket + sb->keys > sb->nbuckets)
154 goto err;
155
156 err = "Invalid superblock: first bucket comes before end of super";
157 if (sb->first_bucket * sb->bucket_size < 16)
158 goto err;
159
160 err = NULL;
161err:
162 return err;
163}
164
165
166static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
167 struct cache_sb_disk **res)
168{
169 const char *err;
170 struct cache_sb_disk *s;
171 struct folio *folio;
172 unsigned int i;
173
174 folio = mapping_read_folio_gfp(bdev->bd_mapping,
175 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
176 if (IS_ERR(folio))
177 return "IO error";
178 s = folio_address(folio) + offset_in_folio(folio, SB_OFFSET);
179
180 sb->offset = le64_to_cpu(s->offset);
181 sb->version = le64_to_cpu(s->version);
182
183 memcpy(sb->magic, s->magic, 16);
184 memcpy(sb->uuid, s->uuid, 16);
185 memcpy(sb->set_uuid, s->set_uuid, 16);
186 memcpy(sb->label, s->label, SB_LABEL_SIZE);
187
188 sb->flags = le64_to_cpu(s->flags);
189 sb->seq = le64_to_cpu(s->seq);
190 sb->last_mount = le32_to_cpu(s->last_mount);
191 sb->keys = le16_to_cpu(s->keys);
192
193 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
194 sb->d[i] = le64_to_cpu(s->d[i]);
195
196 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u\n",
197 sb->version, sb->flags, sb->seq, sb->keys);
198
199 err = "Not a bcache superblock (bad offset)";
200 if (sb->offset != SB_SECTOR)
201 goto err;
202
203 err = "Not a bcache superblock (bad magic)";
204 if (memcmp(sb->magic, bcache_magic, 16))
205 goto err;
206
207 err = "Bad checksum";
208 if (s->csum != csum_set(s))
209 goto err;
210
211 err = "Bad UUID";
212 if (bch_is_zero(sb->uuid, 16))
213 goto err;
214
215 sb->block_size = le16_to_cpu(s->block_size);
216
217 err = "Superblock block size smaller than device block size";
218 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
219 goto err;
220
221 switch (sb->version) {
222 case BCACHE_SB_VERSION_BDEV:
223 sb->data_offset = BDEV_DATA_START_DEFAULT;
224 break;
225 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
226 case BCACHE_SB_VERSION_BDEV_WITH_FEATURES:
227 sb->data_offset = le64_to_cpu(s->data_offset);
228
229 err = "Bad data offset";
230 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
231 goto err;
232
233 break;
234 case BCACHE_SB_VERSION_CDEV:
235 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
236 err = read_super_common(sb, bdev, s);
237 if (err)
238 goto err;
239 break;
240 case BCACHE_SB_VERSION_CDEV_WITH_FEATURES:
241 /*
242 * Feature bits are needed in read_super_common(),
243 * convert them firstly.
244 */
245 sb->feature_compat = le64_to_cpu(s->feature_compat);
246 sb->feature_incompat = le64_to_cpu(s->feature_incompat);
247 sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat);
248
249 /* Check incompatible features */
250 err = "Unsupported compatible feature found";
251 if (bch_has_unknown_compat_features(sb))
252 goto err;
253
254 err = "Unsupported read-only compatible feature found";
255 if (bch_has_unknown_ro_compat_features(sb))
256 goto err;
257
258 err = "Unsupported incompatible feature found";
259 if (bch_has_unknown_incompat_features(sb))
260 goto err;
261
262 err = read_super_common(sb, bdev, s);
263 if (err)
264 goto err;
265 break;
266 default:
267 err = "Unsupported superblock version";
268 goto err;
269 }
270
271 sb->last_mount = (u32)ktime_get_real_seconds();
272 *res = s;
273 return NULL;
274err:
275 folio_put(folio);
276 return err;
277}
278
279static void write_bdev_super_endio(struct bio *bio)
280{
281 struct cached_dev *dc = bio->bi_private;
282
283 if (bio->bi_status)
284 bch_count_backing_io_errors(dc, bio);
285
286 closure_put(&dc->sb_write);
287}
288
289static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
290 struct bio *bio)
291{
292 unsigned int i;
293
294 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
295 bio->bi_iter.bi_sector = SB_SECTOR;
296 bio_add_virt_nofail(bio, out, SB_SIZE);
297
298 out->offset = cpu_to_le64(sb->offset);
299
300 memcpy(out->uuid, sb->uuid, 16);
301 memcpy(out->set_uuid, sb->set_uuid, 16);
302 memcpy(out->label, sb->label, SB_LABEL_SIZE);
303
304 out->flags = cpu_to_le64(sb->flags);
305 out->seq = cpu_to_le64(sb->seq);
306
307 out->last_mount = cpu_to_le32(sb->last_mount);
308 out->first_bucket = cpu_to_le16(sb->first_bucket);
309 out->keys = cpu_to_le16(sb->keys);
310
311 for (i = 0; i < sb->keys; i++)
312 out->d[i] = cpu_to_le64(sb->d[i]);
313
314 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
315 out->feature_compat = cpu_to_le64(sb->feature_compat);
316 out->feature_incompat = cpu_to_le64(sb->feature_incompat);
317 out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
318 }
319
320 out->version = cpu_to_le64(sb->version);
321 out->csum = csum_set(out);
322
323 pr_debug("ver %llu, flags %llu, seq %llu\n",
324 sb->version, sb->flags, sb->seq);
325
326 submit_bio(bio);
327}
328
329static CLOSURE_CALLBACK(bch_write_bdev_super_unlock)
330{
331 closure_type(dc, struct cached_dev, sb_write);
332
333 up(&dc->sb_write_mutex);
334}
335
336void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
337{
338 struct closure *cl = &dc->sb_write;
339 struct bio *bio = &dc->sb_bio;
340
341 down(&dc->sb_write_mutex);
342 closure_init(cl, parent);
343
344 bio_init(bio, dc->bdev, dc->sb_bv, 1, 0);
345 bio->bi_end_io = write_bdev_super_endio;
346 bio->bi_private = dc;
347
348 closure_get(cl);
349 /* I/O request sent to backing device */
350 __write_super(&dc->sb, dc->sb_disk, bio);
351
352 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
353}
354
355static void write_super_endio(struct bio *bio)
356{
357 struct cache *ca = bio->bi_private;
358
359 /* is_read = 0 */
360 bch_count_io_errors(ca, bio->bi_status, 0,
361 "writing superblock");
362 closure_put(&ca->set->sb_write);
363}
364
365static CLOSURE_CALLBACK(bcache_write_super_unlock)
366{
367 closure_type(c, struct cache_set, sb_write);
368
369 up(&c->sb_write_mutex);
370}
371
372void bcache_write_super(struct cache_set *c)
373{
374 struct closure *cl = &c->sb_write;
375 struct cache *ca = c->cache;
376 struct bio *bio = &ca->sb_bio;
377 unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
378
379 down(&c->sb_write_mutex);
380 closure_init(cl, &c->cl);
381
382 ca->sb.seq++;
383
384 if (ca->sb.version < version)
385 ca->sb.version = version;
386
387 bio_init(bio, ca->bdev, ca->sb_bv, 1, 0);
388 bio->bi_end_io = write_super_endio;
389 bio->bi_private = ca;
390
391 closure_get(cl);
392 __write_super(&ca->sb, ca->sb_disk, bio);
393
394 closure_return_with_destructor(cl, bcache_write_super_unlock);
395}
396
397/* UUID io */
398
399static void uuid_endio(struct bio *bio)
400{
401 struct closure *cl = bio->bi_private;
402 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
403
404 cache_set_err_on(bio->bi_status, c, "accessing uuids");
405 bch_bbio_free(bio, c);
406 closure_put(cl);
407}
408
409static CLOSURE_CALLBACK(uuid_io_unlock)
410{
411 closure_type(c, struct cache_set, uuid_write);
412
413 up(&c->uuid_write_mutex);
414}
415
416static void uuid_io(struct cache_set *c, blk_opf_t opf, struct bkey *k,
417 struct closure *parent)
418{
419 struct closure *cl = &c->uuid_write;
420 struct uuid_entry *u;
421 unsigned int i;
422 char buf[80];
423
424 BUG_ON(!parent);
425 down(&c->uuid_write_mutex);
426 closure_init(cl, parent);
427
428 for (i = 0; i < KEY_PTRS(k); i++) {
429 struct bio *bio = bch_bbio_alloc(c);
430
431 bio->bi_opf = opf | REQ_SYNC | REQ_META;
432 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
433
434 bio->bi_end_io = uuid_endio;
435 bio->bi_private = cl;
436 bch_bio_map(bio, c->uuids);
437
438 bch_submit_bbio(bio, c, k, i);
439
440 if ((opf & REQ_OP_MASK) != REQ_OP_WRITE)
441 break;
442 }
443
444 bch_extent_to_text(buf, sizeof(buf), k);
445 pr_debug("%s UUIDs at %s\n", (opf & REQ_OP_MASK) == REQ_OP_WRITE ?
446 "wrote" : "read", buf);
447
448 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
449 if (!bch_is_zero(u->uuid, 16))
450 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
451 u - c->uuids, u->uuid, u->label,
452 u->first_reg, u->last_reg, u->invalidated);
453
454 closure_return_with_destructor(cl, uuid_io_unlock);
455}
456
457static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
458{
459 struct bkey *k = &j->uuid_bucket;
460
461 if (__bch_btree_ptr_invalid(c, k))
462 return "bad uuid pointer";
463
464 bkey_copy(&c->uuid_bucket, k);
465 uuid_io(c, REQ_OP_READ, k, cl);
466
467 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
468 struct uuid_entry_v0 *u0 = (void *) c->uuids;
469 struct uuid_entry *u1 = (void *) c->uuids;
470 int i;
471
472 closure_sync(cl);
473
474 /*
475 * Since the new uuid entry is bigger than the old, we have to
476 * convert starting at the highest memory address and work down
477 * in order to do it in place
478 */
479
480 for (i = c->nr_uuids - 1;
481 i >= 0;
482 --i) {
483 memcpy(u1[i].uuid, u0[i].uuid, 16);
484 memcpy(u1[i].label, u0[i].label, 32);
485
486 u1[i].first_reg = u0[i].first_reg;
487 u1[i].last_reg = u0[i].last_reg;
488 u1[i].invalidated = u0[i].invalidated;
489
490 u1[i].flags = 0;
491 u1[i].sectors = 0;
492 }
493 }
494
495 return NULL;
496}
497
498static int __uuid_write(struct cache_set *c)
499{
500 BKEY_PADDED(key) k;
501 struct closure cl;
502 struct cache *ca = c->cache;
503 unsigned int size;
504
505 closure_init_stack(&cl);
506 lockdep_assert_held(&bch_register_lock);
507
508 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
509 return 1;
510
511 size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS;
512 SET_KEY_SIZE(&k.key, size);
513 uuid_io(c, REQ_OP_WRITE, &k.key, &cl);
514 closure_sync(&cl);
515
516 /* Only one bucket used for uuid write */
517 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
518
519 bkey_copy(&c->uuid_bucket, &k.key);
520 bkey_put(c, &k.key);
521 return 0;
522}
523
524int bch_uuid_write(struct cache_set *c)
525{
526 int ret = __uuid_write(c);
527
528 if (!ret)
529 bch_journal_meta(c, NULL);
530
531 return ret;
532}
533
534static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
535{
536 struct uuid_entry *u;
537
538 for (u = c->uuids;
539 u < c->uuids + c->nr_uuids; u++)
540 if (!memcmp(u->uuid, uuid, 16))
541 return u;
542
543 return NULL;
544}
545
546static struct uuid_entry *uuid_find_empty(struct cache_set *c)
547{
548 static const char zero_uuid[16] __nonstring =
549 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
550
551 return uuid_find(c, zero_uuid);
552}
553
554/*
555 * Bucket priorities/gens:
556 *
557 * For each bucket, we store on disk its
558 * 8 bit gen
559 * 16 bit priority
560 *
561 * See alloc.c for an explanation of the gen. The priority is used to implement
562 * lru (and in the future other) cache replacement policies; for most purposes
563 * it's just an opaque integer.
564 *
565 * The gens and the priorities don't have a whole lot to do with each other, and
566 * it's actually the gens that must be written out at specific times - it's no
567 * big deal if the priorities don't get written, if we lose them we just reuse
568 * buckets in suboptimal order.
569 *
570 * On disk they're stored in a packed array, and in as many buckets are required
571 * to fit them all. The buckets we use to store them form a list; the journal
572 * header points to the first bucket, the first bucket points to the second
573 * bucket, et cetera.
574 *
575 * This code is used by the allocation code; periodically (whenever it runs out
576 * of buckets to allocate from) the allocation code will invalidate some
577 * buckets, but it can't use those buckets until their new gens are safely on
578 * disk.
579 */
580
581static void prio_endio(struct bio *bio)
582{
583 struct cache *ca = bio->bi_private;
584
585 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
586 bch_bbio_free(bio, ca->set);
587 closure_put(&ca->prio);
588}
589
590static void prio_io(struct cache *ca, uint64_t bucket, blk_opf_t opf)
591{
592 struct closure *cl = &ca->prio;
593 struct bio *bio = bch_bbio_alloc(ca->set);
594
595 closure_init_stack(cl);
596
597 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
598 bio_set_dev(bio, ca->bdev);
599 bio->bi_iter.bi_size = meta_bucket_bytes(&ca->sb);
600
601 bio->bi_end_io = prio_endio;
602 bio->bi_private = ca;
603 bio->bi_opf = opf | REQ_SYNC | REQ_META;
604 bch_bio_map(bio, ca->disk_buckets);
605
606 closure_bio_submit(ca->set, bio, &ca->prio);
607 closure_sync(cl);
608}
609
610int bch_prio_write(struct cache *ca, bool wait)
611{
612 int i;
613 struct bucket *b;
614 struct closure cl;
615
616 pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n",
617 fifo_used(&ca->free[RESERVE_PRIO]),
618 fifo_used(&ca->free[RESERVE_NONE]),
619 fifo_used(&ca->free_inc));
620
621 /*
622 * Pre-check if there are enough free buckets. In the non-blocking
623 * scenario it's better to fail early rather than starting to allocate
624 * buckets and do a cleanup later in case of failure.
625 */
626 if (!wait) {
627 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
628 fifo_used(&ca->free[RESERVE_NONE]);
629 if (prio_buckets(ca) > avail)
630 return -ENOMEM;
631 }
632
633 closure_init_stack(&cl);
634
635 lockdep_assert_held(&ca->set->bucket_lock);
636
637 ca->disk_buckets->seq++;
638
639 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
640 &ca->meta_sectors_written);
641
642 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
643 long bucket;
644 struct prio_set *p = ca->disk_buckets;
645 struct bucket_disk *d = p->data;
646 struct bucket_disk *end = d + prios_per_bucket(ca);
647
648 for (b = ca->buckets + i * prios_per_bucket(ca);
649 b < ca->buckets + ca->sb.nbuckets && d < end;
650 b++, d++) {
651 d->prio = cpu_to_le16(b->prio);
652 d->gen = b->gen;
653 }
654
655 p->next_bucket = ca->prio_buckets[i + 1];
656 p->magic = pset_magic(&ca->sb);
657 p->csum = bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8);
658
659 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
660 BUG_ON(bucket == -1);
661
662 mutex_unlock(&ca->set->bucket_lock);
663 prio_io(ca, bucket, REQ_OP_WRITE);
664 mutex_lock(&ca->set->bucket_lock);
665
666 ca->prio_buckets[i] = bucket;
667 atomic_dec_bug(&ca->buckets[bucket].pin);
668 }
669
670 mutex_unlock(&ca->set->bucket_lock);
671
672 bch_journal_meta(ca->set, &cl);
673 closure_sync(&cl);
674
675 mutex_lock(&ca->set->bucket_lock);
676
677 /*
678 * Don't want the old priorities to get garbage collected until after we
679 * finish writing the new ones, and they're journalled
680 */
681 for (i = 0; i < prio_buckets(ca); i++) {
682 if (ca->prio_last_buckets[i])
683 __bch_bucket_free(ca,
684 &ca->buckets[ca->prio_last_buckets[i]]);
685
686 ca->prio_last_buckets[i] = ca->prio_buckets[i];
687 }
688 return 0;
689}
690
691static int prio_read(struct cache *ca, uint64_t bucket)
692{
693 struct prio_set *p = ca->disk_buckets;
694 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
695 struct bucket *b;
696 unsigned int bucket_nr = 0;
697 int ret = -EIO;
698
699 for (b = ca->buckets;
700 b < ca->buckets + ca->sb.nbuckets;
701 b++, d++) {
702 if (d == end) {
703 ca->prio_buckets[bucket_nr] = bucket;
704 ca->prio_last_buckets[bucket_nr] = bucket;
705 bucket_nr++;
706
707 prio_io(ca, bucket, REQ_OP_READ);
708
709 if (p->csum !=
710 bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) {
711 pr_warn("bad csum reading priorities\n");
712 goto out;
713 }
714
715 if (p->magic != pset_magic(&ca->sb)) {
716 pr_warn("bad magic reading priorities\n");
717 goto out;
718 }
719
720 bucket = p->next_bucket;
721 d = p->data;
722 }
723
724 b->prio = le16_to_cpu(d->prio);
725 b->gen = b->last_gc = d->gen;
726 }
727
728 ret = 0;
729out:
730 return ret;
731}
732
733/* Bcache device */
734
735static int open_dev(struct gendisk *disk, blk_mode_t mode)
736{
737 struct bcache_device *d = disk->private_data;
738
739 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
740 return -ENXIO;
741
742 closure_get(&d->cl);
743 return 0;
744}
745
746static void release_dev(struct gendisk *b)
747{
748 struct bcache_device *d = b->private_data;
749
750 closure_put(&d->cl);
751}
752
753static int ioctl_dev(struct block_device *b, blk_mode_t mode,
754 unsigned int cmd, unsigned long arg)
755{
756 struct bcache_device *d = b->bd_disk->private_data;
757
758 return d->ioctl(d, mode, cmd, arg);
759}
760
761static const struct block_device_operations bcache_cached_ops = {
762 .submit_bio = cached_dev_submit_bio,
763 .open = open_dev,
764 .release = release_dev,
765 .ioctl = ioctl_dev,
766 .owner = THIS_MODULE,
767};
768
769static const struct block_device_operations bcache_flash_ops = {
770 .submit_bio = flash_dev_submit_bio,
771 .open = open_dev,
772 .release = release_dev,
773 .ioctl = ioctl_dev,
774 .owner = THIS_MODULE,
775};
776
777void bcache_device_stop(struct bcache_device *d)
778{
779 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
780 /*
781 * closure_fn set to
782 * - cached device: cached_dev_flush()
783 * - flash dev: flash_dev_flush()
784 */
785 closure_queue(&d->cl);
786}
787
788static void bcache_device_unlink(struct bcache_device *d)
789{
790 lockdep_assert_held(&bch_register_lock);
791
792 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
793 struct cache *ca = d->c->cache;
794
795 sysfs_remove_link(&d->c->kobj, d->name);
796 sysfs_remove_link(&d->kobj, "cache");
797
798 bd_unlink_disk_holder(ca->bdev, d->disk);
799 }
800}
801
802static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
803 const char *name)
804{
805 struct cache *ca = c->cache;
806 int ret;
807
808 bd_link_disk_holder(ca->bdev, d->disk);
809
810 snprintf(d->name, BCACHEDEVNAME_SIZE,
811 "%s%u", name, d->id);
812
813 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
814 if (ret < 0)
815 pr_err("Couldn't create device -> cache set symlink\n");
816
817 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
818 if (ret < 0)
819 pr_err("Couldn't create cache set -> device symlink\n");
820
821 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
822}
823
824static void bcache_device_detach(struct bcache_device *d)
825{
826 lockdep_assert_held(&bch_register_lock);
827
828 atomic_dec(&d->c->attached_dev_nr);
829
830 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
831 struct uuid_entry *u = d->c->uuids + d->id;
832
833 SET_UUID_FLASH_ONLY(u, 0);
834 memcpy(u->uuid, invalid_uuid, 16);
835 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
836 bch_uuid_write(d->c);
837 }
838
839 bcache_device_unlink(d);
840
841 d->c->devices[d->id] = NULL;
842 closure_put(&d->c->caching);
843 d->c = NULL;
844}
845
846static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
847 unsigned int id)
848{
849 d->id = id;
850 d->c = c;
851 c->devices[id] = d;
852
853 if (id >= c->devices_max_used)
854 c->devices_max_used = id + 1;
855
856 closure_get(&c->caching);
857}
858
859static inline int first_minor_to_idx(int first_minor)
860{
861 return (first_minor/BCACHE_MINORS);
862}
863
864static inline int idx_to_first_minor(int idx)
865{
866 return (idx * BCACHE_MINORS);
867}
868
869static void bcache_device_free(struct bcache_device *d)
870{
871 struct gendisk *disk = d->disk;
872
873 lockdep_assert_held(&bch_register_lock);
874
875 if (disk)
876 pr_info("%s stopped\n", disk->disk_name);
877 else
878 pr_err("bcache device (NULL gendisk) stopped\n");
879
880 if (d->c)
881 bcache_device_detach(d);
882
883 if (disk) {
884 ida_free(&bcache_device_idx,
885 first_minor_to_idx(disk->first_minor));
886 put_disk(disk);
887 }
888
889 bioset_exit(&d->bio_split);
890 bioset_exit(&d->bio_detached);
891 kvfree(d->full_dirty_stripes);
892 kvfree(d->stripe_sectors_dirty);
893
894 closure_debug_destroy(&d->cl);
895}
896
897static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
898 sector_t sectors, struct block_device *cached_bdev,
899 const struct block_device_operations *ops)
900{
901 const size_t max_stripes = min_t(size_t, INT_MAX,
902 SIZE_MAX / sizeof(atomic_t));
903 struct queue_limits lim = {
904 .max_hw_sectors = UINT_MAX,
905 .max_sectors = UINT_MAX,
906 .max_segment_size = UINT_MAX,
907 .max_segments = BIO_MAX_VECS,
908 .max_hw_discard_sectors = UINT_MAX,
909 .io_min = block_size,
910 .logical_block_size = block_size,
911 .physical_block_size = block_size,
912 .features = BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA,
913 };
914 uint64_t n;
915 int idx;
916
917 if (cached_bdev) {
918 d->stripe_size = bdev_io_opt(cached_bdev) >> SECTOR_SHIFT;
919 lim.io_opt = umax(block_size, bdev_io_opt(cached_bdev));
920 }
921 if (!d->stripe_size)
922 d->stripe_size = 1 << 31;
923 else if (d->stripe_size < BCH_MIN_STRIPE_SZ)
924 d->stripe_size = roundup(BCH_MIN_STRIPE_SZ, d->stripe_size);
925
926 n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
927 if (!n || n > max_stripes) {
928 pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
929 n);
930 return -ENOMEM;
931 }
932 d->nr_stripes = n;
933
934 n = d->nr_stripes * sizeof(atomic_t);
935 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
936 if (!d->stripe_sectors_dirty)
937 return -ENOMEM;
938
939 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
940 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
941 if (!d->full_dirty_stripes)
942 goto out_free_stripe_sectors_dirty;
943
944 idx = ida_alloc_max(&bcache_device_idx, BCACHE_DEVICE_IDX_MAX - 1,
945 GFP_KERNEL);
946 if (idx < 0)
947 goto out_free_full_dirty_stripes;
948
949 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
950 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
951 goto out_ida_remove;
952
953 if (bioset_init(&d->bio_detached, 4,
954 offsetof(struct detached_dev_io_private, bio),
955 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
956 goto out_bioset_split_exit;
957
958 if (lim.logical_block_size > PAGE_SIZE && cached_bdev) {
959 /*
960 * This should only happen with BCACHE_SB_VERSION_BDEV.
961 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
962 */
963 pr_info("bcache%i: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
964 idx, lim.logical_block_size,
965 PAGE_SIZE, bdev_logical_block_size(cached_bdev));
966
967 /* This also adjusts physical block size/min io size if needed */
968 lim.logical_block_size = bdev_logical_block_size(cached_bdev);
969 }
970
971 d->disk = blk_alloc_disk(&lim, NUMA_NO_NODE);
972 if (IS_ERR(d->disk))
973 goto out_bioset_detach_exit;
974
975 set_capacity(d->disk, sectors);
976 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
977
978 d->disk->major = bcache_major;
979 d->disk->first_minor = idx_to_first_minor(idx);
980 d->disk->minors = BCACHE_MINORS;
981 d->disk->fops = ops;
982 d->disk->private_data = d;
983 return 0;
984
985out_bioset_detach_exit:
986 bioset_exit(&d->bio_detached);
987out_bioset_split_exit:
988 bioset_exit(&d->bio_split);
989out_ida_remove:
990 ida_free(&bcache_device_idx, idx);
991out_free_full_dirty_stripes:
992 kvfree(d->full_dirty_stripes);
993out_free_stripe_sectors_dirty:
994 kvfree(d->stripe_sectors_dirty);
995 return -ENOMEM;
996
997}
998
999/* Cached device */
1000
1001static void calc_cached_dev_sectors(struct cache_set *c)
1002{
1003 uint64_t sectors = 0;
1004 struct cached_dev *dc;
1005
1006 list_for_each_entry(dc, &c->cached_devs, list)
1007 sectors += bdev_nr_sectors(dc->bdev);
1008
1009 c->cached_dev_sectors = sectors;
1010}
1011
1012#define BACKING_DEV_OFFLINE_TIMEOUT 5
1013static int cached_dev_status_update(void *arg)
1014{
1015 struct cached_dev *dc = arg;
1016 struct request_queue *q;
1017
1018 /*
1019 * If this delayed worker is stopping outside, directly quit here.
1020 * dc->io_disable might be set via sysfs interface, so check it
1021 * here too.
1022 */
1023 while (!kthread_should_stop() && !dc->io_disable) {
1024 q = bdev_get_queue(dc->bdev);
1025 if (blk_queue_dying(q))
1026 dc->offline_seconds++;
1027 else
1028 dc->offline_seconds = 0;
1029
1030 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1031 pr_err("%pg: device offline for %d seconds\n",
1032 dc->bdev,
1033 BACKING_DEV_OFFLINE_TIMEOUT);
1034 pr_err("%s: disable I/O request due to backing device offline\n",
1035 dc->disk.name);
1036 dc->io_disable = true;
1037 /* let others know earlier that io_disable is true */
1038 smp_mb();
1039 bcache_device_stop(&dc->disk);
1040 break;
1041 }
1042 schedule_timeout_interruptible(HZ);
1043 }
1044
1045 wait_for_kthread_stop();
1046 return 0;
1047}
1048
1049
1050int bch_cached_dev_run(struct cached_dev *dc)
1051{
1052 int ret = 0;
1053 struct bcache_device *d = &dc->disk;
1054 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1055 char *env[] = {
1056 "DRIVER=bcache",
1057 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1058 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1059 NULL,
1060 };
1061
1062 if (dc->io_disable) {
1063 pr_err("I/O disabled on cached dev %pg\n", dc->bdev);
1064 ret = -EIO;
1065 goto out;
1066 }
1067
1068 if (atomic_xchg(&dc->running, 1)) {
1069 pr_info("cached dev %pg is running already\n", dc->bdev);
1070 ret = -EBUSY;
1071 goto out;
1072 }
1073
1074 if (!d->c &&
1075 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1076 struct closure cl;
1077
1078 closure_init_stack(&cl);
1079
1080 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1081 bch_write_bdev_super(dc, &cl);
1082 closure_sync(&cl);
1083 }
1084
1085 ret = add_disk(d->disk);
1086 if (ret)
1087 goto out;
1088 bd_link_disk_holder(dc->bdev, dc->disk.disk);
1089 /*
1090 * won't show up in the uevent file, use udevadm monitor -e instead
1091 * only class / kset properties are persistent
1092 */
1093 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1094
1095 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1096 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1097 &d->kobj, "bcache")) {
1098 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1099 ret = -ENOMEM;
1100 goto out;
1101 }
1102
1103 dc->status_update_thread = kthread_run(cached_dev_status_update,
1104 dc, "bcache_status_update");
1105 if (IS_ERR(dc->status_update_thread)) {
1106 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1107 }
1108
1109out:
1110 kfree(env[1]);
1111 kfree(env[2]);
1112 kfree(buf);
1113 return ret;
1114}
1115
1116/*
1117 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1118 * work dc->writeback_rate_update is running. Wait until the routine
1119 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1120 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1121 * seconds, give up waiting here and continue to cancel it too.
1122 */
1123static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1124{
1125 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1126
1127 do {
1128 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1129 &dc->disk.flags))
1130 break;
1131 time_out--;
1132 schedule_timeout_interruptible(1);
1133 } while (time_out > 0);
1134
1135 if (time_out == 0)
1136 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1137
1138 cancel_delayed_work_sync(&dc->writeback_rate_update);
1139}
1140
1141static void cached_dev_detach_finish(struct work_struct *w)
1142{
1143 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1144 struct cache_set *c = dc->disk.c;
1145
1146 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1147 BUG_ON(refcount_read(&dc->count));
1148
1149
1150 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1151 cancel_writeback_rate_update_dwork(dc);
1152
1153 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1154 kthread_stop(dc->writeback_thread);
1155 dc->writeback_thread = NULL;
1156 }
1157
1158 mutex_lock(&bch_register_lock);
1159
1160 bcache_device_detach(&dc->disk);
1161 list_move(&dc->list, &uncached_devices);
1162 calc_cached_dev_sectors(c);
1163
1164 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1165 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1166
1167 mutex_unlock(&bch_register_lock);
1168
1169 pr_info("Caching disabled for %pg\n", dc->bdev);
1170
1171 /* Drop ref we took in cached_dev_detach() */
1172 closure_put(&dc->disk.cl);
1173}
1174
1175void bch_cached_dev_detach(struct cached_dev *dc)
1176{
1177 lockdep_assert_held(&bch_register_lock);
1178
1179 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1180 return;
1181
1182 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1183 return;
1184
1185 /*
1186 * Block the device from being closed and freed until we're finished
1187 * detaching
1188 */
1189 closure_get(&dc->disk.cl);
1190
1191 bch_writeback_queue(dc);
1192
1193 cached_dev_put(dc);
1194}
1195
1196int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1197 uint8_t *set_uuid)
1198{
1199 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1200 struct uuid_entry *u;
1201 struct cached_dev *exist_dc, *t;
1202 int ret = 0;
1203
1204 if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
1205 (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
1206 return -ENOENT;
1207
1208 if (dc->disk.c) {
1209 pr_err("Can't attach %pg: already attached\n", dc->bdev);
1210 return -EINVAL;
1211 }
1212
1213 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1214 pr_err("Can't attach %pg: shutting down\n", dc->bdev);
1215 return -EINVAL;
1216 }
1217
1218 if (dc->sb.block_size < c->cache->sb.block_size) {
1219 /* Will die */
1220 pr_err("Couldn't attach %pg: block size less than set's block size\n",
1221 dc->bdev);
1222 return -EINVAL;
1223 }
1224
1225 /* Check whether already attached */
1226 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1227 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1228 pr_err("Tried to attach %pg but duplicate UUID already attached\n",
1229 dc->bdev);
1230
1231 return -EINVAL;
1232 }
1233 }
1234
1235 u = uuid_find(c, dc->sb.uuid);
1236
1237 if (u &&
1238 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1239 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1240 memcpy(u->uuid, invalid_uuid, 16);
1241 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1242 u = NULL;
1243 }
1244
1245 if (!u) {
1246 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1247 pr_err("Couldn't find uuid for %pg in set\n", dc->bdev);
1248 return -ENOENT;
1249 }
1250
1251 u = uuid_find_empty(c);
1252 if (!u) {
1253 pr_err("Not caching %pg, no room for UUID\n", dc->bdev);
1254 return -EINVAL;
1255 }
1256 }
1257
1258 /*
1259 * Deadlocks since we're called via sysfs...
1260 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1261 */
1262
1263 if (bch_is_zero(u->uuid, 16)) {
1264 struct closure cl;
1265
1266 closure_init_stack(&cl);
1267
1268 memcpy(u->uuid, dc->sb.uuid, 16);
1269 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1270 u->first_reg = u->last_reg = rtime;
1271 bch_uuid_write(c);
1272
1273 memcpy(dc->sb.set_uuid, c->set_uuid, 16);
1274 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1275
1276 bch_write_bdev_super(dc, &cl);
1277 closure_sync(&cl);
1278 } else {
1279 u->last_reg = rtime;
1280 bch_uuid_write(c);
1281 }
1282
1283 bcache_device_attach(&dc->disk, c, u - c->uuids);
1284 list_move(&dc->list, &c->cached_devs);
1285 calc_cached_dev_sectors(c);
1286
1287 /*
1288 * dc->c must be set before dc->count != 0 - paired with the mb in
1289 * cached_dev_get()
1290 */
1291 smp_wmb();
1292 refcount_set(&dc->count, 1);
1293
1294 /* Block writeback thread, but spawn it */
1295 down_write(&dc->writeback_lock);
1296 if (bch_cached_dev_writeback_start(dc)) {
1297 up_write(&dc->writeback_lock);
1298 pr_err("Couldn't start writeback facilities for %s\n",
1299 dc->disk.disk->disk_name);
1300 return -ENOMEM;
1301 }
1302
1303 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1304 atomic_set(&dc->has_dirty, 1);
1305 bch_writeback_queue(dc);
1306 }
1307
1308 bch_sectors_dirty_init(&dc->disk);
1309
1310 ret = bch_cached_dev_run(dc);
1311 if (ret && (ret != -EBUSY)) {
1312 up_write(&dc->writeback_lock);
1313 /*
1314 * bch_register_lock is held, bcache_device_stop() is not
1315 * able to be directly called. The kthread and kworker
1316 * created previously in bch_cached_dev_writeback_start()
1317 * have to be stopped manually here.
1318 */
1319 kthread_stop(dc->writeback_thread);
1320 cancel_writeback_rate_update_dwork(dc);
1321 pr_err("Couldn't run cached device %pg\n", dc->bdev);
1322 return ret;
1323 }
1324
1325 bcache_device_link(&dc->disk, c, "bdev");
1326 atomic_inc(&c->attached_dev_nr);
1327
1328 if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
1329 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1330 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1331 set_disk_ro(dc->disk.disk, 1);
1332 }
1333
1334 /* Allow the writeback thread to proceed */
1335 up_write(&dc->writeback_lock);
1336
1337 pr_info("Caching %pg as %s on set %pU\n",
1338 dc->bdev,
1339 dc->disk.disk->disk_name,
1340 dc->disk.c->set_uuid);
1341 return 0;
1342}
1343
1344/* when dc->disk.kobj released */
1345void bch_cached_dev_release(struct kobject *kobj)
1346{
1347 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1348 disk.kobj);
1349 kfree(dc);
1350 module_put(THIS_MODULE);
1351}
1352
1353static CLOSURE_CALLBACK(cached_dev_free)
1354{
1355 closure_type(dc, struct cached_dev, disk.cl);
1356
1357 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1358 cancel_writeback_rate_update_dwork(dc);
1359
1360 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1361 kthread_stop(dc->writeback_thread);
1362 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1363 kthread_stop(dc->status_update_thread);
1364
1365 mutex_lock(&bch_register_lock);
1366
1367 if (atomic_read(&dc->running)) {
1368 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1369 del_gendisk(dc->disk.disk);
1370 }
1371 bcache_device_free(&dc->disk);
1372 list_del(&dc->list);
1373
1374 mutex_unlock(&bch_register_lock);
1375
1376 /*
1377 * Wait for any pending sb_write to complete before free.
1378 * The sb_bio is embedded in struct cached_dev, so we must
1379 * ensure no I/O is in progress.
1380 */
1381 down(&dc->sb_write_mutex);
1382 up(&dc->sb_write_mutex);
1383
1384 if (dc->sb_disk)
1385 folio_put(virt_to_folio(dc->sb_disk));
1386
1387 if (dc->bdev_file)
1388 fput(dc->bdev_file);
1389
1390 wake_up(&unregister_wait);
1391
1392 kobject_put(&dc->disk.kobj);
1393}
1394
1395static CLOSURE_CALLBACK(cached_dev_flush)
1396{
1397 closure_type(dc, struct cached_dev, disk.cl);
1398 struct bcache_device *d = &dc->disk;
1399
1400 mutex_lock(&bch_register_lock);
1401 bcache_device_unlink(d);
1402 mutex_unlock(&bch_register_lock);
1403
1404 bch_cache_accounting_destroy(&dc->accounting);
1405 kobject_del(&d->kobj);
1406
1407 continue_at(cl, cached_dev_free, system_percpu_wq);
1408}
1409
1410static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1411{
1412 int ret;
1413 struct io *io;
1414 struct request_queue *q = bdev_get_queue(dc->bdev);
1415
1416 __module_get(THIS_MODULE);
1417 INIT_LIST_HEAD(&dc->list);
1418 closure_init(&dc->disk.cl, NULL);
1419 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_percpu_wq);
1420 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1421 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1422 sema_init(&dc->sb_write_mutex, 1);
1423 INIT_LIST_HEAD(&dc->io_lru);
1424 spin_lock_init(&dc->io_lock);
1425 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1426
1427 dc->sequential_cutoff = 4 << 20;
1428
1429 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1430 list_add(&io->lru, &dc->io_lru);
1431 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1432 }
1433
1434 if (bdev_io_opt(dc->bdev))
1435 dc->partial_stripes_expensive = !!(q->limits.features &
1436 BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE);
1437
1438 ret = bcache_device_init(&dc->disk, block_size,
1439 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
1440 dc->bdev, &bcache_cached_ops);
1441 if (ret)
1442 return ret;
1443
1444 atomic_set(&dc->io_errors, 0);
1445 dc->io_disable = false;
1446 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1447 /* default to auto */
1448 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1449
1450 bch_cached_dev_request_init(dc);
1451 bch_cached_dev_writeback_init(dc);
1452 return 0;
1453}
1454
1455/* Cached device - bcache superblock */
1456
1457static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1458 struct file *bdev_file,
1459 struct cached_dev *dc)
1460{
1461 const char *err = "cannot allocate memory";
1462 struct cache_set *c;
1463 int ret = -ENOMEM;
1464
1465 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1466 dc->bdev_file = bdev_file;
1467 dc->bdev = file_bdev(bdev_file);
1468 dc->sb_disk = sb_disk;
1469
1470 if (cached_dev_init(dc, sb->block_size << 9))
1471 goto err;
1472
1473 err = "error creating kobject";
1474 if (kobject_add(&dc->disk.kobj, bdev_kobj(dc->bdev), "bcache"))
1475 goto err;
1476 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1477 goto err;
1478
1479 pr_info("registered backing device %pg\n", dc->bdev);
1480
1481 list_add(&dc->list, &uncached_devices);
1482 /* attach to a matched cache set if it exists */
1483 list_for_each_entry(c, &bch_cache_sets, list)
1484 bch_cached_dev_attach(dc, c, NULL);
1485
1486 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1487 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1488 err = "failed to run cached device";
1489 ret = bch_cached_dev_run(dc);
1490 if (ret)
1491 goto err;
1492 }
1493
1494 return 0;
1495err:
1496 pr_notice("error %pg: %s\n", dc->bdev, err);
1497 bcache_device_stop(&dc->disk);
1498 return ret;
1499}
1500
1501/* Flash only volumes */
1502
1503/* When d->kobj released */
1504void bch_flash_dev_release(struct kobject *kobj)
1505{
1506 struct bcache_device *d = container_of(kobj, struct bcache_device,
1507 kobj);
1508 kfree(d);
1509}
1510
1511static CLOSURE_CALLBACK(flash_dev_free)
1512{
1513 closure_type(d, struct bcache_device, cl);
1514
1515 mutex_lock(&bch_register_lock);
1516 atomic_long_sub(bcache_dev_sectors_dirty(d),
1517 &d->c->flash_dev_dirty_sectors);
1518 del_gendisk(d->disk);
1519 bcache_device_free(d);
1520 mutex_unlock(&bch_register_lock);
1521 kobject_put(&d->kobj);
1522}
1523
1524static CLOSURE_CALLBACK(flash_dev_flush)
1525{
1526 closure_type(d, struct bcache_device, cl);
1527
1528 mutex_lock(&bch_register_lock);
1529 bcache_device_unlink(d);
1530 mutex_unlock(&bch_register_lock);
1531 kobject_del(&d->kobj);
1532 continue_at(cl, flash_dev_free, system_percpu_wq);
1533}
1534
1535static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1536{
1537 int err = -ENOMEM;
1538 struct bcache_device *d = kzalloc_obj(struct bcache_device);
1539 if (!d)
1540 goto err_ret;
1541
1542 closure_init(&d->cl, NULL);
1543 set_closure_fn(&d->cl, flash_dev_flush, system_percpu_wq);
1544
1545 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1546
1547 if (bcache_device_init(d, block_bytes(c->cache), u->sectors,
1548 NULL, &bcache_flash_ops))
1549 goto err;
1550
1551 bcache_device_attach(d, c, u - c->uuids);
1552 bch_sectors_dirty_init(d);
1553 bch_flash_dev_request_init(d);
1554 err = add_disk(d->disk);
1555 if (err)
1556 goto err;
1557
1558 err = kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache");
1559 if (err)
1560 goto err;
1561
1562 bcache_device_link(d, c, "volume");
1563
1564 if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
1565 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1566 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1567 set_disk_ro(d->disk, 1);
1568 }
1569
1570 return 0;
1571err:
1572 kobject_put(&d->kobj);
1573err_ret:
1574 return err;
1575}
1576
1577static int flash_devs_run(struct cache_set *c)
1578{
1579 int ret = 0;
1580 struct uuid_entry *u;
1581
1582 for (u = c->uuids;
1583 u < c->uuids + c->nr_uuids && !ret;
1584 u++)
1585 if (UUID_FLASH_ONLY(u))
1586 ret = flash_dev_run(c, u);
1587
1588 return ret;
1589}
1590
1591int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1592{
1593 struct uuid_entry *u;
1594
1595 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1596 return -EINTR;
1597
1598 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1599 return -EPERM;
1600
1601 u = uuid_find_empty(c);
1602 if (!u) {
1603 pr_err("Can't create volume, no room for UUID\n");
1604 return -EINVAL;
1605 }
1606
1607 get_random_bytes(u->uuid, 16);
1608 memset(u->label, 0, 32);
1609 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1610
1611 SET_UUID_FLASH_ONLY(u, 1);
1612 u->sectors = size >> 9;
1613
1614 bch_uuid_write(c);
1615
1616 return flash_dev_run(c, u);
1617}
1618
1619bool bch_cached_dev_error(struct cached_dev *dc)
1620{
1621 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1622 return false;
1623
1624 dc->io_disable = true;
1625 /* make others know io_disable is true earlier */
1626 smp_mb();
1627
1628 pr_err("stop %s: too many IO errors on backing device %pg\n",
1629 dc->disk.disk->disk_name, dc->bdev);
1630
1631 bcache_device_stop(&dc->disk);
1632 return true;
1633}
1634
1635/* Cache set */
1636
1637__printf(2, 3)
1638bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1639{
1640 struct va_format vaf;
1641 va_list args;
1642
1643 if (c->on_error != ON_ERROR_PANIC &&
1644 test_bit(CACHE_SET_STOPPING, &c->flags))
1645 return false;
1646
1647 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1648 pr_info("CACHE_SET_IO_DISABLE already set\n");
1649
1650 /*
1651 * XXX: we can be called from atomic context
1652 * acquire_console_sem();
1653 */
1654
1655 va_start(args, fmt);
1656
1657 vaf.fmt = fmt;
1658 vaf.va = &args;
1659
1660 pr_err("error on %pU: %pV, disabling caching\n",
1661 c->set_uuid, &vaf);
1662
1663 va_end(args);
1664
1665 if (c->on_error == ON_ERROR_PANIC)
1666 panic("panic forced after error\n");
1667
1668 bch_cache_set_unregister(c);
1669 return true;
1670}
1671
1672/* When c->kobj released */
1673void bch_cache_set_release(struct kobject *kobj)
1674{
1675 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1676
1677 kfree(c);
1678 module_put(THIS_MODULE);
1679}
1680
1681static CLOSURE_CALLBACK(cache_set_free)
1682{
1683 closure_type(c, struct cache_set, cl);
1684 struct cache *ca;
1685
1686 debugfs_remove(c->debug);
1687
1688 bch_open_buckets_free(c);
1689 bch_btree_cache_free(c);
1690 bch_journal_free(c);
1691
1692 mutex_lock(&bch_register_lock);
1693 bch_bset_sort_state_free(&c->sort);
1694 free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
1695
1696 ca = c->cache;
1697 if (ca) {
1698 ca->set = NULL;
1699 c->cache = NULL;
1700 kobject_put(&ca->kobj);
1701 }
1702
1703
1704 if (c->moving_gc_wq)
1705 destroy_workqueue(c->moving_gc_wq);
1706 bioset_exit(&c->bio_split);
1707 mempool_exit(&c->fill_iter);
1708 mempool_exit(&c->bio_meta);
1709 mempool_exit(&c->search);
1710 kfree(c->devices);
1711
1712 list_del(&c->list);
1713 mutex_unlock(&bch_register_lock);
1714
1715 pr_info("Cache set %pU unregistered\n", c->set_uuid);
1716 wake_up(&unregister_wait);
1717
1718 closure_debug_destroy(&c->cl);
1719 kobject_put(&c->kobj);
1720}
1721
1722static CLOSURE_CALLBACK(cache_set_flush)
1723{
1724 closure_type(c, struct cache_set, caching);
1725 struct cache *ca = c->cache;
1726 struct btree *b;
1727
1728 bch_cache_accounting_destroy(&c->accounting);
1729
1730 kobject_put(&c->internal);
1731 kobject_del(&c->kobj);
1732
1733 if (!IS_ERR_OR_NULL(c->gc_thread))
1734 kthread_stop(c->gc_thread);
1735
1736 if (!IS_ERR_OR_NULL(c->root))
1737 list_add(&c->root->list, &c->btree_cache);
1738
1739 /*
1740 * Avoid flushing cached nodes if cache set is retiring
1741 * due to too many I/O errors detected.
1742 */
1743 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1744 list_for_each_entry(b, &c->btree_cache, list) {
1745 mutex_lock(&b->write_lock);
1746 if (btree_node_dirty(b))
1747 __bch_btree_node_write(b, NULL);
1748 mutex_unlock(&b->write_lock);
1749 }
1750
1751 /*
1752 * If the register_cache_set() call to bch_cache_set_alloc() failed,
1753 * ca has not been assigned a value and return error.
1754 * So we need check ca is not NULL during bch_cache_set_unregister().
1755 */
1756 if (ca && ca->alloc_thread)
1757 kthread_stop(ca->alloc_thread);
1758
1759 if (c->journal.cur) {
1760 cancel_delayed_work_sync(&c->journal.work);
1761 /* flush last journal entry if needed */
1762 c->journal.work.work.func(&c->journal.work.work);
1763 }
1764
1765 closure_return(cl);
1766}
1767
1768/*
1769 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1770 * cache set is unregistering due to too many I/O errors. In this condition,
1771 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1772 * value and whether the broken cache has dirty data:
1773 *
1774 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1775 * BCH_CACHED_STOP_AUTO 0 NO
1776 * BCH_CACHED_STOP_AUTO 1 YES
1777 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1778 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1779 *
1780 * The expected behavior is, if stop_when_cache_set_failed is configured to
1781 * "auto" via sysfs interface, the bcache device will not be stopped if the
1782 * backing device is clean on the broken cache device.
1783 */
1784static void conditional_stop_bcache_device(struct cache_set *c,
1785 struct bcache_device *d,
1786 struct cached_dev *dc)
1787{
1788 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1789 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1790 d->disk->disk_name, c->set_uuid);
1791 bcache_device_stop(d);
1792 } else if (atomic_read(&dc->has_dirty)) {
1793 /*
1794 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1795 * and dc->has_dirty == 1
1796 */
1797 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1798 d->disk->disk_name);
1799 /*
1800 * There might be a small time gap that cache set is
1801 * released but bcache device is not. Inside this time
1802 * gap, regular I/O requests will directly go into
1803 * backing device as no cache set attached to. This
1804 * behavior may also introduce potential inconsistence
1805 * data in writeback mode while cache is dirty.
1806 * Therefore before calling bcache_device_stop() due
1807 * to a broken cache device, dc->io_disable should be
1808 * explicitly set to true.
1809 */
1810 dc->io_disable = true;
1811 /* make others know io_disable is true earlier */
1812 smp_mb();
1813 bcache_device_stop(d);
1814 } else {
1815 /*
1816 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1817 * and dc->has_dirty == 0
1818 */
1819 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1820 d->disk->disk_name);
1821 }
1822}
1823
1824static CLOSURE_CALLBACK(__cache_set_unregister)
1825{
1826 closure_type(c, struct cache_set, caching);
1827 struct cached_dev *dc;
1828 struct bcache_device *d;
1829 size_t i;
1830
1831 mutex_lock(&bch_register_lock);
1832
1833 for (i = 0; i < c->devices_max_used; i++) {
1834 d = c->devices[i];
1835 if (!d)
1836 continue;
1837
1838 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1839 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1840 dc = container_of(d, struct cached_dev, disk);
1841 bch_cached_dev_detach(dc);
1842 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1843 conditional_stop_bcache_device(c, d, dc);
1844 } else {
1845 bcache_device_stop(d);
1846 }
1847 }
1848
1849 mutex_unlock(&bch_register_lock);
1850
1851 continue_at(cl, cache_set_flush, system_percpu_wq);
1852}
1853
1854void bch_cache_set_stop(struct cache_set *c)
1855{
1856 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1857 /* closure_fn set to __cache_set_unregister() */
1858 closure_queue(&c->caching);
1859}
1860
1861void bch_cache_set_unregister(struct cache_set *c)
1862{
1863 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1864 bch_cache_set_stop(c);
1865}
1866
1867#define alloc_meta_bucket_pages(gfp, sb) \
1868 ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1869
1870struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1871{
1872 int iter_size;
1873 struct cache *ca = container_of(sb, struct cache, sb);
1874 struct cache_set *c = kzalloc_obj(struct cache_set);
1875
1876 if (!c)
1877 return NULL;
1878
1879 __module_get(THIS_MODULE);
1880 closure_init(&c->cl, NULL);
1881 set_closure_fn(&c->cl, cache_set_free, system_percpu_wq);
1882
1883 closure_init(&c->caching, &c->cl);
1884 set_closure_fn(&c->caching, __cache_set_unregister, system_percpu_wq);
1885
1886 /* Maybe create continue_at_noreturn() and use it here? */
1887 closure_set_stopped(&c->cl);
1888 closure_put(&c->cl);
1889
1890 kobject_init(&c->kobj, &bch_cache_set_ktype);
1891 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1892
1893 bch_cache_accounting_init(&c->accounting, &c->cl);
1894
1895 memcpy(c->set_uuid, sb->set_uuid, 16);
1896
1897 c->cache = ca;
1898 c->cache->set = c;
1899 c->bucket_bits = ilog2(sb->bucket_size);
1900 c->block_bits = ilog2(sb->block_size);
1901 c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
1902 c->devices_max_used = 0;
1903 atomic_set(&c->attached_dev_nr, 0);
1904 c->btree_pages = meta_bucket_pages(sb);
1905 if (c->btree_pages > BTREE_MAX_PAGES)
1906 c->btree_pages = max_t(int, c->btree_pages / 4,
1907 BTREE_MAX_PAGES);
1908
1909 sema_init(&c->sb_write_mutex, 1);
1910 mutex_init(&c->bucket_lock);
1911 init_waitqueue_head(&c->btree_cache_wait);
1912 spin_lock_init(&c->btree_cannibalize_lock);
1913 init_waitqueue_head(&c->bucket_wait);
1914 init_waitqueue_head(&c->gc_wait);
1915 sema_init(&c->uuid_write_mutex, 1);
1916
1917 spin_lock_init(&c->btree_gc_time.lock);
1918 spin_lock_init(&c->btree_split_time.lock);
1919 spin_lock_init(&c->btree_read_time.lock);
1920
1921 bch_moving_init_cache_set(c);
1922
1923 INIT_LIST_HEAD(&c->list);
1924 INIT_LIST_HEAD(&c->cached_devs);
1925 INIT_LIST_HEAD(&c->btree_cache);
1926 INIT_LIST_HEAD(&c->btree_cache_freeable);
1927 INIT_LIST_HEAD(&c->btree_cache_freed);
1928 INIT_LIST_HEAD(&c->data_buckets);
1929
1930 iter_size = sizeof(struct btree_iter) +
1931 ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) *
1932 sizeof(struct btree_iter_set);
1933
1934 c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1935 if (!c->devices)
1936 goto err;
1937
1938 if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1939 goto err;
1940
1941 if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1942 sizeof(struct bbio) +
1943 sizeof(struct bio_vec) * meta_bucket_pages(sb)))
1944 goto err;
1945
1946 if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1947 goto err;
1948
1949 if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1950 BIOSET_NEED_RESCUER))
1951 goto err;
1952
1953 c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
1954 if (!c->uuids)
1955 goto err;
1956
1957 c->moving_gc_wq = alloc_workqueue("bcache_gc",
1958 WQ_MEM_RECLAIM | WQ_PERCPU, 0);
1959 if (!c->moving_gc_wq)
1960 goto err;
1961
1962 if (bch_journal_alloc(c))
1963 goto err;
1964
1965 if (bch_btree_cache_alloc(c))
1966 goto err;
1967
1968 if (bch_open_buckets_alloc(c))
1969 goto err;
1970
1971 if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1972 goto err;
1973
1974 c->congested_read_threshold_us = 2000;
1975 c->congested_write_threshold_us = 20000;
1976 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1977 c->idle_max_writeback_rate_enabled = 1;
1978 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1979
1980 return c;
1981err:
1982 bch_cache_set_unregister(c);
1983 return NULL;
1984}
1985
1986static int run_cache_set(struct cache_set *c)
1987{
1988 const char *err = "cannot allocate memory";
1989 struct cached_dev *dc, *t;
1990 struct cache *ca = c->cache;
1991 struct closure cl;
1992 LIST_HEAD(journal);
1993 struct journal_replay *l;
1994
1995 closure_init_stack(&cl);
1996
1997 c->nbuckets = ca->sb.nbuckets;
1998 set_gc_sectors(c);
1999
2000 if (CACHE_SYNC(&c->cache->sb)) {
2001 struct bkey *k;
2002 struct jset *j;
2003
2004 err = "cannot allocate memory for journal";
2005 if (bch_journal_read(c, &journal))
2006 goto err;
2007
2008 pr_debug("btree_journal_read() done\n");
2009
2010 err = "no journal entries found";
2011 if (list_empty(&journal))
2012 goto err;
2013
2014 j = &list_entry(journal.prev, struct journal_replay, list)->j;
2015
2016 err = "IO error reading priorities";
2017 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2018 goto err;
2019
2020 /*
2021 * If prio_read() fails it'll call cache_set_error and we'll
2022 * tear everything down right away, but if we perhaps checked
2023 * sooner we could avoid journal replay.
2024 */
2025
2026 k = &j->btree_root;
2027
2028 err = "bad btree root";
2029 if (__bch_btree_ptr_invalid(c, k))
2030 goto err;
2031
2032 err = "error reading btree root";
2033 c->root = bch_btree_node_get(c, NULL, k,
2034 j->btree_level,
2035 true, NULL);
2036 if (IS_ERR(c->root))
2037 goto err;
2038
2039 list_del_init(&c->root->list);
2040 rw_unlock(true, c->root);
2041
2042 err = uuid_read(c, j, &cl);
2043 if (err)
2044 goto err;
2045
2046 err = "error in recovery";
2047 if (bch_btree_check(c))
2048 goto err;
2049
2050 bch_journal_mark(c, &journal);
2051 bch_initial_gc_finish(c);
2052 pr_debug("btree_check() done\n");
2053
2054 /*
2055 * bcache_journal_next() can't happen sooner, or
2056 * btree_gc_finish() will give spurious errors about last_gc >
2057 * gc_gen - this is a hack but oh well.
2058 */
2059 bch_journal_next(&c->journal);
2060
2061 err = "error starting allocator thread";
2062 if (bch_cache_allocator_start(ca))
2063 goto err;
2064
2065 /*
2066 * First place it's safe to allocate: btree_check() and
2067 * btree_gc_finish() have to run before we have buckets to
2068 * allocate, and bch_bucket_alloc_set() might cause a journal
2069 * entry to be written so bcache_journal_next() has to be called
2070 * first.
2071 *
2072 * If the uuids were in the old format we have to rewrite them
2073 * before the next journal entry is written:
2074 */
2075 if (j->version < BCACHE_JSET_VERSION_UUID)
2076 __uuid_write(c);
2077
2078 err = "bcache: replay journal failed";
2079 if (bch_journal_replay(c, &journal))
2080 goto err;
2081 } else {
2082 unsigned int j;
2083
2084 pr_notice("invalidating existing data\n");
2085 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2086 2, SB_JOURNAL_BUCKETS);
2087
2088 for (j = 0; j < ca->sb.keys; j++)
2089 ca->sb.d[j] = ca->sb.first_bucket + j;
2090
2091 bch_initial_gc_finish(c);
2092
2093 err = "error starting allocator thread";
2094 if (bch_cache_allocator_start(ca))
2095 goto err;
2096
2097 mutex_lock(&c->bucket_lock);
2098 bch_prio_write(ca, true);
2099 mutex_unlock(&c->bucket_lock);
2100
2101 err = "cannot allocate new UUID bucket";
2102 if (__uuid_write(c))
2103 goto err;
2104
2105 err = "cannot allocate new btree root";
2106 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2107 if (IS_ERR(c->root))
2108 goto err;
2109
2110 mutex_lock(&c->root->write_lock);
2111 bkey_copy_key(&c->root->key, &MAX_KEY);
2112 bch_btree_node_write(c->root, &cl);
2113 mutex_unlock(&c->root->write_lock);
2114
2115 bch_btree_set_root(c->root);
2116 rw_unlock(true, c->root);
2117
2118 /*
2119 * We don't want to write the first journal entry until
2120 * everything is set up - fortunately journal entries won't be
2121 * written until the SET_CACHE_SYNC() here:
2122 */
2123 SET_CACHE_SYNC(&c->cache->sb, true);
2124
2125 bch_journal_next(&c->journal);
2126 bch_journal_meta(c, &cl);
2127 }
2128
2129 err = "error starting gc thread";
2130 if (bch_gc_thread_start(c))
2131 goto err;
2132
2133 closure_sync(&cl);
2134 c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
2135 bcache_write_super(c);
2136
2137 if (bch_has_feature_obso_large_bucket(&c->cache->sb))
2138 pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
2139
2140 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2141 bch_cached_dev_attach(dc, c, NULL);
2142
2143 flash_devs_run(c);
2144
2145 bch_journal_space_reserve(&c->journal);
2146 set_bit(CACHE_SET_RUNNING, &c->flags);
2147 return 0;
2148err:
2149 while (!list_empty(&journal)) {
2150 l = list_first_entry(&journal, struct journal_replay, list);
2151 list_del(&l->list);
2152 kfree(l);
2153 }
2154
2155 closure_sync(&cl);
2156
2157 bch_cache_set_error(c, "%s", err);
2158
2159 return -EIO;
2160}
2161
2162static const char *register_cache_set(struct cache *ca)
2163{
2164 char buf[12];
2165 const char *err = "cannot allocate memory";
2166 struct cache_set *c;
2167
2168 list_for_each_entry(c, &bch_cache_sets, list)
2169 if (!memcmp(c->set_uuid, ca->sb.set_uuid, 16)) {
2170 if (c->cache)
2171 return "duplicate cache set member";
2172
2173 goto found;
2174 }
2175
2176 c = bch_cache_set_alloc(&ca->sb);
2177 if (!c)
2178 return err;
2179
2180 err = "error creating kobject";
2181 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->set_uuid) ||
2182 kobject_add(&c->internal, &c->kobj, "internal"))
2183 goto err;
2184
2185 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2186 goto err;
2187
2188 bch_debug_init_cache_set(c);
2189
2190 list_add(&c->list, &bch_cache_sets);
2191found:
2192 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2193 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2194 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2195 goto err;
2196
2197 kobject_get(&ca->kobj);
2198 ca->set = c;
2199 ca->set->cache = ca;
2200
2201 err = "failed to run cache set";
2202 if (run_cache_set(c) < 0)
2203 goto err;
2204
2205 return NULL;
2206err:
2207 bch_cache_set_unregister(c);
2208 return err;
2209}
2210
2211/* Cache device */
2212
2213/* When ca->kobj released */
2214void bch_cache_release(struct kobject *kobj)
2215{
2216 struct cache *ca = container_of(kobj, struct cache, kobj);
2217 unsigned int i;
2218
2219 if (ca->set) {
2220 BUG_ON(ca->set->cache != ca);
2221 ca->set->cache = NULL;
2222 }
2223
2224 free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2225 kfree(ca->prio_buckets);
2226 vfree(ca->buckets);
2227
2228 free_heap(&ca->heap);
2229 free_fifo(&ca->free_inc);
2230
2231 for (i = 0; i < RESERVE_NR; i++)
2232 free_fifo(&ca->free[i]);
2233
2234 if (ca->sb_disk)
2235 folio_put(virt_to_folio(ca->sb_disk));
2236
2237 if (ca->bdev_file)
2238 fput(ca->bdev_file);
2239
2240 kfree(ca);
2241 module_put(THIS_MODULE);
2242}
2243
2244static int cache_alloc(struct cache *ca)
2245{
2246 size_t free;
2247 size_t btree_buckets;
2248 struct bucket *b;
2249 int ret = -ENOMEM;
2250 const char *err = NULL;
2251
2252 __module_get(THIS_MODULE);
2253 kobject_init(&ca->kobj, &bch_cache_ktype);
2254
2255 bio_init_inline(&ca->journal.bio, NULL, 8, 0);
2256
2257 /*
2258 * When the cache disk is first registered, ca->sb.njournal_buckets
2259 * is zero, and it is assigned in run_cache_set().
2260 *
2261 * When ca->sb.njournal_buckets is not zero, journal exists,
2262 * and in bch_journal_replay(), tree node may split.
2263 * The worst situation is all journal buckets are valid journal,
2264 * and all the keys need to replay, so the number of RESERVE_BTREE
2265 * type buckets should be as much as journal buckets.
2266 *
2267 * If the number of RESERVE_BTREE type buckets is too few, the
2268 * bch_allocator_thread() may hang up and unable to allocate
2269 * bucket. The situation is roughly as follows:
2270 *
2271 * 1. In bch_data_insert_keys(), if the operation is not op->replace,
2272 * it will call the bch_journal(), which increments the journal_ref
2273 * counter. This counter is only decremented after bch_btree_insert
2274 * completes.
2275 *
2276 * 2. When calling bch_btree_insert, if the btree needs to split,
2277 * it will call btree_split() and btree_check_reserve() to check
2278 * whether there are enough reserved buckets in the RESERVE_BTREE
2279 * slot. If not enough, bcache_btree_root() will repeatedly retry.
2280 *
2281 * 3. Normally, the bch_allocator_thread is responsible for filling
2282 * the reservation slots from the free_inc bucket list. When the
2283 * free_inc bucket list is exhausted, the bch_allocator_thread
2284 * will call invalidate_buckets() until free_inc is refilled.
2285 * Then bch_allocator_thread calls bch_prio_write() once. and
2286 * bch_prio_write() will call bch_journal_meta() and waits for
2287 * the journal write to complete.
2288 *
2289 * 4. During journal_write, journal_write_unlocked() is be called.
2290 * If journal full occurs, journal_reclaim() and btree_flush_write()
2291 * will be called sequentially, then retry journal_write.
2292 *
2293 * 5. When 2 and 4 occur together, IO will hung up and cannot recover.
2294 *
2295 * Therefore, reserve more RESERVE_BTREE type buckets.
2296 */
2297 btree_buckets = clamp_t(size_t, ca->sb.nbuckets >> 7,
2298 32, SB_JOURNAL_BUCKETS);
2299 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2300 if (!free) {
2301 ret = -EPERM;
2302 err = "ca->sb.nbuckets is too small";
2303 goto err_free;
2304 }
2305
2306 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2307 GFP_KERNEL)) {
2308 err = "ca->free[RESERVE_BTREE] alloc failed";
2309 goto err_btree_alloc;
2310 }
2311
2312 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2313 GFP_KERNEL)) {
2314 err = "ca->free[RESERVE_PRIO] alloc failed";
2315 goto err_prio_alloc;
2316 }
2317
2318 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2319 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2320 goto err_movinggc_alloc;
2321 }
2322
2323 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2324 err = "ca->free[RESERVE_NONE] alloc failed";
2325 goto err_none_alloc;
2326 }
2327
2328 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2329 err = "ca->free_inc alloc failed";
2330 goto err_free_inc_alloc;
2331 }
2332
2333 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2334 err = "ca->heap alloc failed";
2335 goto err_heap_alloc;
2336 }
2337
2338 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2339 ca->sb.nbuckets));
2340 if (!ca->buckets) {
2341 err = "ca->buckets alloc failed";
2342 goto err_buckets_alloc;
2343 }
2344
2345 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2346 prio_buckets(ca), 2),
2347 GFP_KERNEL);
2348 if (!ca->prio_buckets) {
2349 err = "ca->prio_buckets alloc failed";
2350 goto err_prio_buckets_alloc;
2351 }
2352
2353 ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2354 if (!ca->disk_buckets) {
2355 err = "ca->disk_buckets alloc failed";
2356 goto err_disk_buckets_alloc;
2357 }
2358
2359 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2360
2361 for_each_bucket(b, ca)
2362 atomic_set(&b->pin, 0);
2363 return 0;
2364
2365err_disk_buckets_alloc:
2366 kfree(ca->prio_buckets);
2367err_prio_buckets_alloc:
2368 vfree(ca->buckets);
2369err_buckets_alloc:
2370 free_heap(&ca->heap);
2371err_heap_alloc:
2372 free_fifo(&ca->free_inc);
2373err_free_inc_alloc:
2374 free_fifo(&ca->free[RESERVE_NONE]);
2375err_none_alloc:
2376 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2377err_movinggc_alloc:
2378 free_fifo(&ca->free[RESERVE_PRIO]);
2379err_prio_alloc:
2380 free_fifo(&ca->free[RESERVE_BTREE]);
2381err_btree_alloc:
2382err_free:
2383 module_put(THIS_MODULE);
2384 if (err)
2385 pr_notice("error %pg: %s\n", ca->bdev, err);
2386 return ret;
2387}
2388
2389static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2390 struct file *bdev_file,
2391 struct cache *ca)
2392{
2393 const char *err = NULL; /* must be set for any error case */
2394 int ret = 0;
2395
2396 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2397 ca->bdev_file = bdev_file;
2398 ca->bdev = file_bdev(bdev_file);
2399 ca->sb_disk = sb_disk;
2400
2401 ret = cache_alloc(ca);
2402 if (ret != 0) {
2403 if (ret == -ENOMEM)
2404 err = "cache_alloc(): -ENOMEM";
2405 else if (ret == -EPERM)
2406 err = "cache_alloc(): cache device is too small";
2407 else
2408 err = "cache_alloc(): unknown error";
2409 pr_notice("error %pg: %s\n", file_bdev(bdev_file), err);
2410 /*
2411 * If we failed here, it means ca->kobj is not initialized yet,
2412 * kobject_put() won't be called and there is no chance to
2413 * call fput() to bdev in bch_cache_release(). So
2414 * we explicitly call fput() on the block device here.
2415 */
2416 fput(bdev_file);
2417 return ret;
2418 }
2419
2420 if (kobject_add(&ca->kobj, bdev_kobj(file_bdev(bdev_file)), "bcache")) {
2421 pr_notice("error %pg: error calling kobject_add\n",
2422 file_bdev(bdev_file));
2423 ret = -ENOMEM;
2424 goto out;
2425 }
2426
2427 mutex_lock(&bch_register_lock);
2428 err = register_cache_set(ca);
2429 mutex_unlock(&bch_register_lock);
2430
2431 if (err) {
2432 ret = -ENODEV;
2433 goto out;
2434 }
2435
2436 pr_info("registered cache device %pg\n", file_bdev(ca->bdev_file));
2437
2438out:
2439 kobject_put(&ca->kobj);
2440 return ret;
2441}
2442
2443/* Global interfaces/init */
2444
2445static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2446 const char *buffer, size_t size);
2447static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2448 struct kobj_attribute *attr,
2449 const char *buffer, size_t size);
2450
2451kobj_attribute_write(register, register_bcache);
2452kobj_attribute_write(register_quiet, register_bcache);
2453kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2454
2455static bool bch_is_open_backing(dev_t dev)
2456{
2457 struct cache_set *c, *tc;
2458 struct cached_dev *dc, *t;
2459
2460 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2461 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2462 if (dc->bdev->bd_dev == dev)
2463 return true;
2464 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2465 if (dc->bdev->bd_dev == dev)
2466 return true;
2467 return false;
2468}
2469
2470static bool bch_is_open_cache(dev_t dev)
2471{
2472 struct cache_set *c, *tc;
2473
2474 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2475 struct cache *ca = c->cache;
2476
2477 if (ca->bdev->bd_dev == dev)
2478 return true;
2479 }
2480
2481 return false;
2482}
2483
2484static bool bch_is_open(dev_t dev)
2485{
2486 return bch_is_open_cache(dev) || bch_is_open_backing(dev);
2487}
2488
2489struct async_reg_args {
2490 struct delayed_work reg_work;
2491 char *path;
2492 struct cache_sb *sb;
2493 struct cache_sb_disk *sb_disk;
2494 struct file *bdev_file;
2495 void *holder;
2496};
2497
2498static void register_bdev_worker(struct work_struct *work)
2499{
2500 int fail = false;
2501 struct async_reg_args *args =
2502 container_of(work, struct async_reg_args, reg_work.work);
2503
2504 mutex_lock(&bch_register_lock);
2505 if (register_bdev(args->sb, args->sb_disk, args->bdev_file,
2506 args->holder) < 0)
2507 fail = true;
2508 mutex_unlock(&bch_register_lock);
2509
2510 if (fail)
2511 pr_info("error %s: fail to register backing device\n",
2512 args->path);
2513 kfree(args->sb);
2514 kfree(args->path);
2515 kfree(args);
2516 module_put(THIS_MODULE);
2517}
2518
2519static void register_cache_worker(struct work_struct *work)
2520{
2521 int fail = false;
2522 struct async_reg_args *args =
2523 container_of(work, struct async_reg_args, reg_work.work);
2524
2525 /* blkdev_put() will be called in bch_cache_release() */
2526 if (register_cache(args->sb, args->sb_disk, args->bdev_file,
2527 args->holder))
2528 fail = true;
2529
2530 if (fail)
2531 pr_info("error %s: fail to register cache device\n",
2532 args->path);
2533 kfree(args->sb);
2534 kfree(args->path);
2535 kfree(args);
2536 module_put(THIS_MODULE);
2537}
2538
2539static void register_device_async(struct async_reg_args *args)
2540{
2541 if (SB_IS_BDEV(args->sb))
2542 INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2543 else
2544 INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2545
2546 /* 10 jiffies is enough for a delay */
2547 queue_delayed_work(system_percpu_wq, &args->reg_work, 10);
2548}
2549
2550static void *alloc_holder_object(struct cache_sb *sb)
2551{
2552 if (SB_IS_BDEV(sb))
2553 return kzalloc_obj(struct cached_dev);
2554 return kzalloc_obj(struct cache);
2555}
2556
2557static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2558 const char *buffer, size_t size)
2559{
2560 const char *err;
2561 char *path = NULL;
2562 struct cache_sb *sb;
2563 struct cache_sb_disk *sb_disk;
2564 struct file *bdev_file, *bdev_file2;
2565 void *holder = NULL;
2566 ssize_t ret;
2567 bool async_registration = false;
2568 bool quiet = false;
2569
2570#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2571 async_registration = true;
2572#endif
2573
2574 ret = -EBUSY;
2575 err = "failed to reference bcache module";
2576 if (!try_module_get(THIS_MODULE))
2577 goto out;
2578
2579 /* For latest state of bcache_is_reboot */
2580 smp_mb();
2581 err = "bcache is in reboot";
2582 if (bcache_is_reboot)
2583 goto out_module_put;
2584
2585 ret = -ENOMEM;
2586 err = "cannot allocate memory";
2587 path = kstrndup(buffer, size, GFP_KERNEL);
2588 if (!path)
2589 goto out_module_put;
2590
2591 sb = kmalloc_obj(struct cache_sb);
2592 if (!sb)
2593 goto out_free_path;
2594
2595 ret = -EINVAL;
2596 err = "failed to open device";
2597 bdev_file = bdev_file_open_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
2598 if (IS_ERR(bdev_file))
2599 goto out_free_sb;
2600
2601 err = read_super(sb, file_bdev(bdev_file), &sb_disk);
2602 if (err)
2603 goto out_blkdev_put;
2604
2605 holder = alloc_holder_object(sb);
2606 if (!holder) {
2607 ret = -ENOMEM;
2608 err = "cannot allocate memory";
2609 goto out_put_sb_folio;
2610 }
2611
2612 /* Now reopen in exclusive mode with proper holder */
2613 bdev_file2 = bdev_file_open_by_dev(file_bdev(bdev_file)->bd_dev,
2614 BLK_OPEN_READ | BLK_OPEN_WRITE, holder, NULL);
2615 fput(bdev_file);
2616 bdev_file = bdev_file2;
2617 if (IS_ERR(bdev_file)) {
2618 ret = PTR_ERR(bdev_file);
2619 bdev_file = NULL;
2620 if (ret == -EBUSY) {
2621 dev_t dev;
2622
2623 mutex_lock(&bch_register_lock);
2624 if (lookup_bdev(strim(path), &dev) == 0 &&
2625 bch_is_open(dev))
2626 err = "device already registered";
2627 else
2628 err = "device busy";
2629 mutex_unlock(&bch_register_lock);
2630 if (attr == &ksysfs_register_quiet) {
2631 quiet = true;
2632 ret = size;
2633 }
2634 }
2635 goto out_free_holder;
2636 }
2637
2638 err = "failed to register device";
2639
2640 if (async_registration) {
2641 /* register in asynchronous way */
2642 struct async_reg_args *args =
2643 kzalloc_obj(struct async_reg_args);
2644
2645 if (!args) {
2646 ret = -ENOMEM;
2647 err = "cannot allocate memory";
2648 goto out_free_holder;
2649 }
2650
2651 args->path = path;
2652 args->sb = sb;
2653 args->sb_disk = sb_disk;
2654 args->bdev_file = bdev_file;
2655 args->holder = holder;
2656 register_device_async(args);
2657 /* No wait and returns to user space */
2658 goto async_done;
2659 }
2660
2661 if (SB_IS_BDEV(sb)) {
2662 mutex_lock(&bch_register_lock);
2663 ret = register_bdev(sb, sb_disk, bdev_file, holder);
2664 mutex_unlock(&bch_register_lock);
2665 /* blkdev_put() will be called in cached_dev_free() */
2666 if (ret < 0)
2667 goto out_free_sb;
2668 } else {
2669 /* blkdev_put() will be called in bch_cache_release() */
2670 ret = register_cache(sb, sb_disk, bdev_file, holder);
2671 if (ret)
2672 goto out_free_sb;
2673 }
2674
2675 kfree(sb);
2676 kfree(path);
2677 module_put(THIS_MODULE);
2678async_done:
2679 return size;
2680
2681out_free_holder:
2682 kfree(holder);
2683out_put_sb_folio:
2684 folio_put(virt_to_folio(sb_disk));
2685out_blkdev_put:
2686 if (bdev_file)
2687 fput(bdev_file);
2688out_free_sb:
2689 kfree(sb);
2690out_free_path:
2691 kfree(path);
2692 path = NULL;
2693out_module_put:
2694 module_put(THIS_MODULE);
2695out:
2696 if (!quiet)
2697 pr_info("error %s: %s\n", path?path:"", err);
2698 return ret;
2699}
2700
2701
2702struct pdev {
2703 struct list_head list;
2704 struct cached_dev *dc;
2705};
2706
2707static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2708 struct kobj_attribute *attr,
2709 const char *buffer,
2710 size_t size)
2711{
2712 LIST_HEAD(pending_devs);
2713 ssize_t ret = size;
2714 struct cached_dev *dc, *tdc;
2715 struct pdev *pdev, *tpdev;
2716 struct cache_set *c, *tc;
2717
2718 mutex_lock(&bch_register_lock);
2719 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2720 pdev = kmalloc_obj(struct pdev);
2721 if (!pdev)
2722 break;
2723 pdev->dc = dc;
2724 list_add(&pdev->list, &pending_devs);
2725 }
2726
2727 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2728 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2729 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2730 char *set_uuid = c->set_uuid;
2731
2732 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2733 list_del(&pdev->list);
2734 kfree(pdev);
2735 break;
2736 }
2737 }
2738 }
2739 mutex_unlock(&bch_register_lock);
2740
2741 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2742 pr_info("delete pdev %p\n", pdev);
2743 list_del(&pdev->list);
2744 bcache_device_stop(&pdev->dc->disk);
2745 kfree(pdev);
2746 }
2747
2748 return ret;
2749}
2750
2751static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2752{
2753 if (bcache_is_reboot)
2754 return NOTIFY_DONE;
2755
2756 if (code == SYS_DOWN ||
2757 code == SYS_HALT ||
2758 code == SYS_POWER_OFF) {
2759 DEFINE_WAIT(wait);
2760 unsigned long start = jiffies;
2761 bool stopped = false;
2762
2763 struct cache_set *c, *tc;
2764 struct cached_dev *dc, *tdc;
2765
2766 mutex_lock(&bch_register_lock);
2767
2768 if (bcache_is_reboot)
2769 goto out;
2770
2771 /* New registration is rejected since now */
2772 bcache_is_reboot = true;
2773 /*
2774 * Make registering caller (if there is) on other CPU
2775 * core know bcache_is_reboot set to true earlier
2776 */
2777 smp_mb();
2778
2779 if (list_empty(&bch_cache_sets) &&
2780 list_empty(&uncached_devices))
2781 goto out;
2782
2783 mutex_unlock(&bch_register_lock);
2784
2785 pr_info("Stopping all devices:\n");
2786
2787 /*
2788 * The reason bch_register_lock is not held to call
2789 * bch_cache_set_stop() and bcache_device_stop() is to
2790 * avoid potential deadlock during reboot, because cache
2791 * set or bcache device stopping process will acquire
2792 * bch_register_lock too.
2793 *
2794 * We are safe here because bcache_is_reboot sets to
2795 * true already, register_bcache() will reject new
2796 * registration now. bcache_is_reboot also makes sure
2797 * bcache_reboot() won't be re-entered on by other thread,
2798 * so there is no race in following list iteration by
2799 * list_for_each_entry_safe().
2800 */
2801 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2802 bch_cache_set_stop(c);
2803
2804 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2805 bcache_device_stop(&dc->disk);
2806
2807
2808 /*
2809 * Give an early chance for other kthreads and
2810 * kworkers to stop themselves
2811 */
2812 schedule();
2813
2814 /* What's a condition variable? */
2815 while (1) {
2816 long timeout = start + 10 * HZ - jiffies;
2817
2818 mutex_lock(&bch_register_lock);
2819 stopped = list_empty(&bch_cache_sets) &&
2820 list_empty(&uncached_devices);
2821
2822 if (timeout < 0 || stopped)
2823 break;
2824
2825 prepare_to_wait(&unregister_wait, &wait,
2826 TASK_UNINTERRUPTIBLE);
2827
2828 mutex_unlock(&bch_register_lock);
2829 schedule_timeout(timeout);
2830 }
2831
2832 finish_wait(&unregister_wait, &wait);
2833
2834 if (stopped)
2835 pr_info("All devices stopped\n");
2836 else
2837 pr_notice("Timeout waiting for devices to be closed\n");
2838out:
2839 mutex_unlock(&bch_register_lock);
2840 }
2841
2842 return NOTIFY_DONE;
2843}
2844
2845static struct notifier_block reboot = {
2846 .notifier_call = bcache_reboot,
2847 .priority = INT_MAX, /* before any real devices */
2848};
2849
2850static void bcache_exit(void)
2851{
2852 bch_debug_exit();
2853 bch_request_exit();
2854 if (bcache_kobj)
2855 kobject_put(bcache_kobj);
2856 if (bcache_wq)
2857 destroy_workqueue(bcache_wq);
2858 if (bch_journal_wq)
2859 destroy_workqueue(bch_journal_wq);
2860 if (bch_flush_wq)
2861 destroy_workqueue(bch_flush_wq);
2862 bch_btree_exit();
2863
2864 if (bcache_major)
2865 unregister_blkdev(bcache_major, "bcache");
2866 unregister_reboot_notifier(&reboot);
2867 mutex_destroy(&bch_register_lock);
2868}
2869
2870/* Check and fixup module parameters */
2871static void check_module_parameters(void)
2872{
2873 if (bch_cutoff_writeback_sync == 0)
2874 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2875 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2876 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2877 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2878 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2879 }
2880
2881 if (bch_cutoff_writeback == 0)
2882 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2883 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2884 pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2885 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2886 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2887 }
2888
2889 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2890 pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2891 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2892 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2893 }
2894}
2895
2896static int __init bcache_init(void)
2897{
2898 static const struct attribute *files[] = {
2899 &ksysfs_register.attr,
2900 &ksysfs_register_quiet.attr,
2901 &ksysfs_pendings_cleanup.attr,
2902 NULL
2903 };
2904
2905 check_module_parameters();
2906
2907 mutex_init(&bch_register_lock);
2908 init_waitqueue_head(&unregister_wait);
2909 register_reboot_notifier(&reboot);
2910
2911 bcache_major = register_blkdev(0, "bcache");
2912 if (bcache_major < 0) {
2913 unregister_reboot_notifier(&reboot);
2914 mutex_destroy(&bch_register_lock);
2915 return bcache_major;
2916 }
2917
2918 if (bch_btree_init())
2919 goto err;
2920
2921 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
2922 if (!bcache_wq)
2923 goto err;
2924
2925 /*
2926 * Let's not make this `WQ_MEM_RECLAIM` for the following reasons:
2927 *
2928 * 1. It used `system_percpu_wq` before which also does no memory reclaim.
2929 * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and
2930 * reduced throughput can be observed.
2931 *
2932 * We still want to user our own queue to not congest the `system_percpu_wq`.
2933 */
2934 bch_flush_wq = alloc_workqueue("bch_flush", WQ_PERCPU, 0);
2935 if (!bch_flush_wq)
2936 goto err;
2937
2938 bch_journal_wq = alloc_workqueue("bch_journal",
2939 WQ_MEM_RECLAIM | WQ_PERCPU, 0);
2940 if (!bch_journal_wq)
2941 goto err;
2942
2943 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2944 if (!bcache_kobj)
2945 goto err;
2946
2947 if (bch_request_init() ||
2948 sysfs_create_files(bcache_kobj, files))
2949 goto err;
2950
2951 bch_debug_init();
2952
2953 bcache_is_reboot = false;
2954
2955 return 0;
2956err:
2957 bcache_exit();
2958 return -ENOMEM;
2959}
2960
2961/*
2962 * Module hooks
2963 */
2964module_exit(bcache_exit);
2965module_init(bcache_init);
2966
2967module_param(bch_cutoff_writeback, uint, 0);
2968MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2969
2970module_param(bch_cutoff_writeback_sync, uint, 0);
2971MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2972
2973MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2974MODULE_AUTHOR("Kent Overstreet <[email protected]>");
2975MODULE_LICENSE("GPL");