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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 <kent.overstreet@gmail.com>
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 page *page;
172 unsigned int i;
173
174 page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
175 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
176 if (IS_ERR(page))
177 return "IO error";
178 s = page_address(page) + offset_in_page(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 put_page(page);
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_page(bio, virt_to_page(out), SB_SIZE,
297 offset_in_page(out));
298
299 out->offset = cpu_to_le64(sb->offset);
300
301 memcpy(out->uuid, sb->uuid, 16);
302 memcpy(out->set_uuid, sb->set_uuid, 16);
303 memcpy(out->label, sb->label, SB_LABEL_SIZE);
304
305 out->flags = cpu_to_le64(sb->flags);
306 out->seq = cpu_to_le64(sb->seq);
307
308 out->last_mount = cpu_to_le32(sb->last_mount);
309 out->first_bucket = cpu_to_le16(sb->first_bucket);
310 out->keys = cpu_to_le16(sb->keys);
311
312 for (i = 0; i < sb->keys; i++)
313 out->d[i] = cpu_to_le64(sb->d[i]);
314
315 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
316 out->feature_compat = cpu_to_le64(sb->feature_compat);
317 out->feature_incompat = cpu_to_le64(sb->feature_incompat);
318 out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
319 }
320
321 out->version = cpu_to_le64(sb->version);
322 out->csum = csum_set(out);
323
324 pr_debug("ver %llu, flags %llu, seq %llu\n",
325 sb->version, sb->flags, sb->seq);
326
327 submit_bio(bio);
328}
329
330static void bch_write_bdev_super_unlock(struct closure *cl)
331{
332 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
333
334 up(&dc->sb_write_mutex);
335}
336
337void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
338{
339 struct closure *cl = &dc->sb_write;
340 struct bio *bio = &dc->sb_bio;
341
342 down(&dc->sb_write_mutex);
343 closure_init(cl, parent);
344
345 bio_init(bio, dc->bdev, dc->sb_bv, 1, 0);
346 bio->bi_end_io = write_bdev_super_endio;
347 bio->bi_private = dc;
348
349 closure_get(cl);
350 /* I/O request sent to backing device */
351 __write_super(&dc->sb, dc->sb_disk, bio);
352
353 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
354}
355
356static void write_super_endio(struct bio *bio)
357{
358 struct cache *ca = bio->bi_private;
359
360 /* is_read = 0 */
361 bch_count_io_errors(ca, bio->bi_status, 0,
362 "writing superblock");
363 closure_put(&ca->set->sb_write);
364}
365
366static void bcache_write_super_unlock(struct closure *cl)
367{
368 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
369
370 up(&c->sb_write_mutex);
371}
372
373void bcache_write_super(struct cache_set *c)
374{
375 struct closure *cl = &c->sb_write;
376 struct cache *ca = c->cache;
377 struct bio *bio = &ca->sb_bio;
378 unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
379
380 down(&c->sb_write_mutex);
381 closure_init(cl, &c->cl);
382
383 ca->sb.seq++;
384
385 if (ca->sb.version < version)
386 ca->sb.version = version;
387
388 bio_init(bio, ca->bdev, ca->sb_bv, 1, 0);
389 bio->bi_end_io = write_super_endio;
390 bio->bi_private = ca;
391
392 closure_get(cl);
393 __write_super(&ca->sb, ca->sb_disk, bio);
394
395 closure_return_with_destructor(cl, bcache_write_super_unlock);
396}
397
398/* UUID io */
399
400static void uuid_endio(struct bio *bio)
401{
402 struct closure *cl = bio->bi_private;
403 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
404
405 cache_set_err_on(bio->bi_status, c, "accessing uuids");
406 bch_bbio_free(bio, c);
407 closure_put(cl);
408}
409
410static void uuid_io_unlock(struct closure *cl)
411{
412 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
413
414 up(&c->uuid_write_mutex);
415}
416
417static void uuid_io(struct cache_set *c, blk_opf_t opf, struct bkey *k,
418 struct closure *parent)
419{
420 struct closure *cl = &c->uuid_write;
421 struct uuid_entry *u;
422 unsigned int i;
423 char buf[80];
424
425 BUG_ON(!parent);
426 down(&c->uuid_write_mutex);
427 closure_init(cl, parent);
428
429 for (i = 0; i < KEY_PTRS(k); i++) {
430 struct bio *bio = bch_bbio_alloc(c);
431
432 bio->bi_opf = opf | REQ_SYNC | REQ_META;
433 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
434
435 bio->bi_end_io = uuid_endio;
436 bio->bi_private = cl;
437 bch_bio_map(bio, c->uuids);
438
439 bch_submit_bbio(bio, c, k, i);
440
441 if ((opf & REQ_OP_MASK) != REQ_OP_WRITE)
442 break;
443 }
444
445 bch_extent_to_text(buf, sizeof(buf), k);
446 pr_debug("%s UUIDs at %s\n", (opf & REQ_OP_MASK) == REQ_OP_WRITE ?
447 "wrote" : "read", buf);
448
449 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
450 if (!bch_is_zero(u->uuid, 16))
451 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
452 u - c->uuids, u->uuid, u->label,
453 u->first_reg, u->last_reg, u->invalidated);
454
455 closure_return_with_destructor(cl, uuid_io_unlock);
456}
457
458static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
459{
460 struct bkey *k = &j->uuid_bucket;
461
462 if (__bch_btree_ptr_invalid(c, k))
463 return "bad uuid pointer";
464
465 bkey_copy(&c->uuid_bucket, k);
466 uuid_io(c, REQ_OP_READ, k, cl);
467
468 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
469 struct uuid_entry_v0 *u0 = (void *) c->uuids;
470 struct uuid_entry *u1 = (void *) c->uuids;
471 int i;
472
473 closure_sync(cl);
474
475 /*
476 * Since the new uuid entry is bigger than the old, we have to
477 * convert starting at the highest memory address and work down
478 * in order to do it in place
479 */
480
481 for (i = c->nr_uuids - 1;
482 i >= 0;
483 --i) {
484 memcpy(u1[i].uuid, u0[i].uuid, 16);
485 memcpy(u1[i].label, u0[i].label, 32);
486
487 u1[i].first_reg = u0[i].first_reg;
488 u1[i].last_reg = u0[i].last_reg;
489 u1[i].invalidated = u0[i].invalidated;
490
491 u1[i].flags = 0;
492 u1[i].sectors = 0;
493 }
494 }
495
496 return NULL;
497}
498
499static int __uuid_write(struct cache_set *c)
500{
501 BKEY_PADDED(key) k;
502 struct closure cl;
503 struct cache *ca = c->cache;
504 unsigned int size;
505
506 closure_init_stack(&cl);
507 lockdep_assert_held(&bch_register_lock);
508
509 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
510 return 1;
511
512 size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS;
513 SET_KEY_SIZE(&k.key, size);
514 uuid_io(c, REQ_OP_WRITE, &k.key, &cl);
515 closure_sync(&cl);
516
517 /* Only one bucket used for uuid write */
518 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
519
520 bkey_copy(&c->uuid_bucket, &k.key);
521 bkey_put(c, &k.key);
522 return 0;
523}
524
525int bch_uuid_write(struct cache_set *c)
526{
527 int ret = __uuid_write(c);
528
529 if (!ret)
530 bch_journal_meta(c, NULL);
531
532 return ret;
533}
534
535static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
536{
537 struct uuid_entry *u;
538
539 for (u = c->uuids;
540 u < c->uuids + c->nr_uuids; u++)
541 if (!memcmp(u->uuid, uuid, 16))
542 return u;
543
544 return NULL;
545}
546
547static struct uuid_entry *uuid_find_empty(struct cache_set *c)
548{
549 static const char zero_uuid[16] = "\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 block_device *b, fmode_t mode)
736{
737 struct bcache_device *d = b->bd_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, fmode_t mode)
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, fmode_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_simple_remove(&bcache_device_idx,
885 first_minor_to_idx(disk->first_minor));
886 put_disk(disk);
887 }
888
889 bioset_exit(&d->bio_split);
890 kvfree(d->full_dirty_stripes);
891 kvfree(d->stripe_sectors_dirty);
892
893 closure_debug_destroy(&d->cl);
894}
895
896static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
897 sector_t sectors, struct block_device *cached_bdev,
898 const struct block_device_operations *ops)
899{
900 struct request_queue *q;
901 const size_t max_stripes = min_t(size_t, INT_MAX,
902 SIZE_MAX / sizeof(atomic_t));
903 uint64_t n;
904 int idx;
905
906 if (!d->stripe_size)
907 d->stripe_size = 1 << 31;
908
909 n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
910 if (!n || n > max_stripes) {
911 pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
912 n);
913 return -ENOMEM;
914 }
915 d->nr_stripes = n;
916
917 n = d->nr_stripes * sizeof(atomic_t);
918 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
919 if (!d->stripe_sectors_dirty)
920 return -ENOMEM;
921
922 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
923 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
924 if (!d->full_dirty_stripes)
925 goto out_free_stripe_sectors_dirty;
926
927 idx = ida_simple_get(&bcache_device_idx, 0,
928 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
929 if (idx < 0)
930 goto out_free_full_dirty_stripes;
931
932 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
933 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
934 goto out_ida_remove;
935
936 d->disk = blk_alloc_disk(NUMA_NO_NODE);
937 if (!d->disk)
938 goto out_bioset_exit;
939
940 set_capacity(d->disk, sectors);
941 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
942
943 d->disk->major = bcache_major;
944 d->disk->first_minor = idx_to_first_minor(idx);
945 d->disk->minors = BCACHE_MINORS;
946 d->disk->fops = ops;
947 d->disk->private_data = d;
948
949 q = d->disk->queue;
950 q->limits.max_hw_sectors = UINT_MAX;
951 q->limits.max_sectors = UINT_MAX;
952 q->limits.max_segment_size = UINT_MAX;
953 q->limits.max_segments = BIO_MAX_VECS;
954 blk_queue_max_discard_sectors(q, UINT_MAX);
955 q->limits.discard_granularity = 512;
956 q->limits.io_min = block_size;
957 q->limits.logical_block_size = block_size;
958 q->limits.physical_block_size = block_size;
959
960 if (q->limits.logical_block_size > PAGE_SIZE && cached_bdev) {
961 /*
962 * This should only happen with BCACHE_SB_VERSION_BDEV.
963 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
964 */
965 pr_info("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
966 d->disk->disk_name, q->limits.logical_block_size,
967 PAGE_SIZE, bdev_logical_block_size(cached_bdev));
968
969 /* This also adjusts physical block size/min io size if needed */
970 blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev));
971 }
972
973 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
974 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
975
976 blk_queue_write_cache(q, true, true);
977
978 return 0;
979
980out_bioset_exit:
981 bioset_exit(&d->bio_split);
982out_ida_remove:
983 ida_simple_remove(&bcache_device_idx, idx);
984out_free_full_dirty_stripes:
985 kvfree(d->full_dirty_stripes);
986out_free_stripe_sectors_dirty:
987 kvfree(d->stripe_sectors_dirty);
988 return -ENOMEM;
989
990}
991
992/* Cached device */
993
994static void calc_cached_dev_sectors(struct cache_set *c)
995{
996 uint64_t sectors = 0;
997 struct cached_dev *dc;
998
999 list_for_each_entry(dc, &c->cached_devs, list)
1000 sectors += bdev_nr_sectors(dc->bdev);
1001
1002 c->cached_dev_sectors = sectors;
1003}
1004
1005#define BACKING_DEV_OFFLINE_TIMEOUT 5
1006static int cached_dev_status_update(void *arg)
1007{
1008 struct cached_dev *dc = arg;
1009 struct request_queue *q;
1010
1011 /*
1012 * If this delayed worker is stopping outside, directly quit here.
1013 * dc->io_disable might be set via sysfs interface, so check it
1014 * here too.
1015 */
1016 while (!kthread_should_stop() && !dc->io_disable) {
1017 q = bdev_get_queue(dc->bdev);
1018 if (blk_queue_dying(q))
1019 dc->offline_seconds++;
1020 else
1021 dc->offline_seconds = 0;
1022
1023 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1024 pr_err("%pg: device offline for %d seconds\n",
1025 dc->bdev,
1026 BACKING_DEV_OFFLINE_TIMEOUT);
1027 pr_err("%s: disable I/O request due to backing device offline\n",
1028 dc->disk.name);
1029 dc->io_disable = true;
1030 /* let others know earlier that io_disable is true */
1031 smp_mb();
1032 bcache_device_stop(&dc->disk);
1033 break;
1034 }
1035 schedule_timeout_interruptible(HZ);
1036 }
1037
1038 wait_for_kthread_stop();
1039 return 0;
1040}
1041
1042
1043int bch_cached_dev_run(struct cached_dev *dc)
1044{
1045 int ret = 0;
1046 struct bcache_device *d = &dc->disk;
1047 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1048 char *env[] = {
1049 "DRIVER=bcache",
1050 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1051 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1052 NULL,
1053 };
1054
1055 if (dc->io_disable) {
1056 pr_err("I/O disabled on cached dev %pg\n", dc->bdev);
1057 ret = -EIO;
1058 goto out;
1059 }
1060
1061 if (atomic_xchg(&dc->running, 1)) {
1062 pr_info("cached dev %pg is running already\n", dc->bdev);
1063 ret = -EBUSY;
1064 goto out;
1065 }
1066
1067 if (!d->c &&
1068 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1069 struct closure cl;
1070
1071 closure_init_stack(&cl);
1072
1073 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1074 bch_write_bdev_super(dc, &cl);
1075 closure_sync(&cl);
1076 }
1077
1078 ret = add_disk(d->disk);
1079 if (ret)
1080 goto out;
1081 bd_link_disk_holder(dc->bdev, dc->disk.disk);
1082 /*
1083 * won't show up in the uevent file, use udevadm monitor -e instead
1084 * only class / kset properties are persistent
1085 */
1086 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1087
1088 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1089 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1090 &d->kobj, "bcache")) {
1091 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1092 ret = -ENOMEM;
1093 goto out;
1094 }
1095
1096 dc->status_update_thread = kthread_run(cached_dev_status_update,
1097 dc, "bcache_status_update");
1098 if (IS_ERR(dc->status_update_thread)) {
1099 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1100 }
1101
1102out:
1103 kfree(env[1]);
1104 kfree(env[2]);
1105 kfree(buf);
1106 return ret;
1107}
1108
1109/*
1110 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1111 * work dc->writeback_rate_update is running. Wait until the routine
1112 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1113 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1114 * seconds, give up waiting here and continue to cancel it too.
1115 */
1116static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1117{
1118 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1119
1120 do {
1121 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1122 &dc->disk.flags))
1123 break;
1124 time_out--;
1125 schedule_timeout_interruptible(1);
1126 } while (time_out > 0);
1127
1128 if (time_out == 0)
1129 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1130
1131 cancel_delayed_work_sync(&dc->writeback_rate_update);
1132}
1133
1134static void cached_dev_detach_finish(struct work_struct *w)
1135{
1136 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1137 struct cache_set *c = dc->disk.c;
1138
1139 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1140 BUG_ON(refcount_read(&dc->count));
1141
1142
1143 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1144 cancel_writeback_rate_update_dwork(dc);
1145
1146 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1147 kthread_stop(dc->writeback_thread);
1148 dc->writeback_thread = NULL;
1149 }
1150
1151 mutex_lock(&bch_register_lock);
1152
1153 bcache_device_detach(&dc->disk);
1154 list_move(&dc->list, &uncached_devices);
1155 calc_cached_dev_sectors(c);
1156
1157 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1158 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1159
1160 mutex_unlock(&bch_register_lock);
1161
1162 pr_info("Caching disabled for %pg\n", dc->bdev);
1163
1164 /* Drop ref we took in cached_dev_detach() */
1165 closure_put(&dc->disk.cl);
1166}
1167
1168void bch_cached_dev_detach(struct cached_dev *dc)
1169{
1170 lockdep_assert_held(&bch_register_lock);
1171
1172 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1173 return;
1174
1175 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1176 return;
1177
1178 /*
1179 * Block the device from being closed and freed until we're finished
1180 * detaching
1181 */
1182 closure_get(&dc->disk.cl);
1183
1184 bch_writeback_queue(dc);
1185
1186 cached_dev_put(dc);
1187}
1188
1189int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1190 uint8_t *set_uuid)
1191{
1192 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1193 struct uuid_entry *u;
1194 struct cached_dev *exist_dc, *t;
1195 int ret = 0;
1196
1197 if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
1198 (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
1199 return -ENOENT;
1200
1201 if (dc->disk.c) {
1202 pr_err("Can't attach %pg: already attached\n", dc->bdev);
1203 return -EINVAL;
1204 }
1205
1206 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1207 pr_err("Can't attach %pg: shutting down\n", dc->bdev);
1208 return -EINVAL;
1209 }
1210
1211 if (dc->sb.block_size < c->cache->sb.block_size) {
1212 /* Will die */
1213 pr_err("Couldn't attach %pg: block size less than set's block size\n",
1214 dc->bdev);
1215 return -EINVAL;
1216 }
1217
1218 /* Check whether already attached */
1219 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1220 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1221 pr_err("Tried to attach %pg but duplicate UUID already attached\n",
1222 dc->bdev);
1223
1224 return -EINVAL;
1225 }
1226 }
1227
1228 u = uuid_find(c, dc->sb.uuid);
1229
1230 if (u &&
1231 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1232 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1233 memcpy(u->uuid, invalid_uuid, 16);
1234 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1235 u = NULL;
1236 }
1237
1238 if (!u) {
1239 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1240 pr_err("Couldn't find uuid for %pg in set\n", dc->bdev);
1241 return -ENOENT;
1242 }
1243
1244 u = uuid_find_empty(c);
1245 if (!u) {
1246 pr_err("Not caching %pg, no room for UUID\n", dc->bdev);
1247 return -EINVAL;
1248 }
1249 }
1250
1251 /*
1252 * Deadlocks since we're called via sysfs...
1253 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1254 */
1255
1256 if (bch_is_zero(u->uuid, 16)) {
1257 struct closure cl;
1258
1259 closure_init_stack(&cl);
1260
1261 memcpy(u->uuid, dc->sb.uuid, 16);
1262 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1263 u->first_reg = u->last_reg = rtime;
1264 bch_uuid_write(c);
1265
1266 memcpy(dc->sb.set_uuid, c->set_uuid, 16);
1267 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1268
1269 bch_write_bdev_super(dc, &cl);
1270 closure_sync(&cl);
1271 } else {
1272 u->last_reg = rtime;
1273 bch_uuid_write(c);
1274 }
1275
1276 bcache_device_attach(&dc->disk, c, u - c->uuids);
1277 list_move(&dc->list, &c->cached_devs);
1278 calc_cached_dev_sectors(c);
1279
1280 /*
1281 * dc->c must be set before dc->count != 0 - paired with the mb in
1282 * cached_dev_get()
1283 */
1284 smp_wmb();
1285 refcount_set(&dc->count, 1);
1286
1287 /* Block writeback thread, but spawn it */
1288 down_write(&dc->writeback_lock);
1289 if (bch_cached_dev_writeback_start(dc)) {
1290 up_write(&dc->writeback_lock);
1291 pr_err("Couldn't start writeback facilities for %s\n",
1292 dc->disk.disk->disk_name);
1293 return -ENOMEM;
1294 }
1295
1296 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1297 atomic_set(&dc->has_dirty, 1);
1298 bch_writeback_queue(dc);
1299 }
1300
1301 bch_sectors_dirty_init(&dc->disk);
1302
1303 ret = bch_cached_dev_run(dc);
1304 if (ret && (ret != -EBUSY)) {
1305 up_write(&dc->writeback_lock);
1306 /*
1307 * bch_register_lock is held, bcache_device_stop() is not
1308 * able to be directly called. The kthread and kworker
1309 * created previously in bch_cached_dev_writeback_start()
1310 * have to be stopped manually here.
1311 */
1312 kthread_stop(dc->writeback_thread);
1313 cancel_writeback_rate_update_dwork(dc);
1314 pr_err("Couldn't run cached device %pg\n", dc->bdev);
1315 return ret;
1316 }
1317
1318 bcache_device_link(&dc->disk, c, "bdev");
1319 atomic_inc(&c->attached_dev_nr);
1320
1321 if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
1322 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1323 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1324 set_disk_ro(dc->disk.disk, 1);
1325 }
1326
1327 /* Allow the writeback thread to proceed */
1328 up_write(&dc->writeback_lock);
1329
1330 pr_info("Caching %pg as %s on set %pU\n",
1331 dc->bdev,
1332 dc->disk.disk->disk_name,
1333 dc->disk.c->set_uuid);
1334 return 0;
1335}
1336
1337/* when dc->disk.kobj released */
1338void bch_cached_dev_release(struct kobject *kobj)
1339{
1340 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1341 disk.kobj);
1342 kfree(dc);
1343 module_put(THIS_MODULE);
1344}
1345
1346static void cached_dev_free(struct closure *cl)
1347{
1348 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1349
1350 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1351 cancel_writeback_rate_update_dwork(dc);
1352
1353 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1354 kthread_stop(dc->writeback_thread);
1355 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1356 kthread_stop(dc->status_update_thread);
1357
1358 mutex_lock(&bch_register_lock);
1359
1360 if (atomic_read(&dc->running)) {
1361 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1362 del_gendisk(dc->disk.disk);
1363 }
1364 bcache_device_free(&dc->disk);
1365 list_del(&dc->list);
1366
1367 mutex_unlock(&bch_register_lock);
1368
1369 if (dc->sb_disk)
1370 put_page(virt_to_page(dc->sb_disk));
1371
1372 if (!IS_ERR_OR_NULL(dc->bdev))
1373 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1374
1375 wake_up(&unregister_wait);
1376
1377 kobject_put(&dc->disk.kobj);
1378}
1379
1380static void cached_dev_flush(struct closure *cl)
1381{
1382 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1383 struct bcache_device *d = &dc->disk;
1384
1385 mutex_lock(&bch_register_lock);
1386 bcache_device_unlink(d);
1387 mutex_unlock(&bch_register_lock);
1388
1389 bch_cache_accounting_destroy(&dc->accounting);
1390 kobject_del(&d->kobj);
1391
1392 continue_at(cl, cached_dev_free, system_wq);
1393}
1394
1395static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1396{
1397 int ret;
1398 struct io *io;
1399 struct request_queue *q = bdev_get_queue(dc->bdev);
1400
1401 __module_get(THIS_MODULE);
1402 INIT_LIST_HEAD(&dc->list);
1403 closure_init(&dc->disk.cl, NULL);
1404 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1405 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1406 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1407 sema_init(&dc->sb_write_mutex, 1);
1408 INIT_LIST_HEAD(&dc->io_lru);
1409 spin_lock_init(&dc->io_lock);
1410 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1411
1412 dc->sequential_cutoff = 4 << 20;
1413
1414 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1415 list_add(&io->lru, &dc->io_lru);
1416 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1417 }
1418
1419 dc->disk.stripe_size = q->limits.io_opt >> 9;
1420
1421 if (dc->disk.stripe_size)
1422 dc->partial_stripes_expensive =
1423 q->limits.raid_partial_stripes_expensive;
1424
1425 ret = bcache_device_init(&dc->disk, block_size,
1426 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
1427 dc->bdev, &bcache_cached_ops);
1428 if (ret)
1429 return ret;
1430
1431 blk_queue_io_opt(dc->disk.disk->queue,
1432 max(queue_io_opt(dc->disk.disk->queue), queue_io_opt(q)));
1433
1434 atomic_set(&dc->io_errors, 0);
1435 dc->io_disable = false;
1436 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1437 /* default to auto */
1438 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1439
1440 bch_cached_dev_request_init(dc);
1441 bch_cached_dev_writeback_init(dc);
1442 return 0;
1443}
1444
1445/* Cached device - bcache superblock */
1446
1447static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1448 struct block_device *bdev,
1449 struct cached_dev *dc)
1450{
1451 const char *err = "cannot allocate memory";
1452 struct cache_set *c;
1453 int ret = -ENOMEM;
1454
1455 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1456 dc->bdev = bdev;
1457 dc->bdev->bd_holder = dc;
1458 dc->sb_disk = sb_disk;
1459
1460 if (cached_dev_init(dc, sb->block_size << 9))
1461 goto err;
1462
1463 err = "error creating kobject";
1464 if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache"))
1465 goto err;
1466 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1467 goto err;
1468
1469 pr_info("registered backing device %pg\n", dc->bdev);
1470
1471 list_add(&dc->list, &uncached_devices);
1472 /* attach to a matched cache set if it exists */
1473 list_for_each_entry(c, &bch_cache_sets, list)
1474 bch_cached_dev_attach(dc, c, NULL);
1475
1476 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1477 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1478 err = "failed to run cached device";
1479 ret = bch_cached_dev_run(dc);
1480 if (ret)
1481 goto err;
1482 }
1483
1484 return 0;
1485err:
1486 pr_notice("error %pg: %s\n", dc->bdev, err);
1487 bcache_device_stop(&dc->disk);
1488 return ret;
1489}
1490
1491/* Flash only volumes */
1492
1493/* When d->kobj released */
1494void bch_flash_dev_release(struct kobject *kobj)
1495{
1496 struct bcache_device *d = container_of(kobj, struct bcache_device,
1497 kobj);
1498 kfree(d);
1499}
1500
1501static void flash_dev_free(struct closure *cl)
1502{
1503 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1504
1505 mutex_lock(&bch_register_lock);
1506 atomic_long_sub(bcache_dev_sectors_dirty(d),
1507 &d->c->flash_dev_dirty_sectors);
1508 del_gendisk(d->disk);
1509 bcache_device_free(d);
1510 mutex_unlock(&bch_register_lock);
1511 kobject_put(&d->kobj);
1512}
1513
1514static void flash_dev_flush(struct closure *cl)
1515{
1516 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1517
1518 mutex_lock(&bch_register_lock);
1519 bcache_device_unlink(d);
1520 mutex_unlock(&bch_register_lock);
1521 kobject_del(&d->kobj);
1522 continue_at(cl, flash_dev_free, system_wq);
1523}
1524
1525static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1526{
1527 int err = -ENOMEM;
1528 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1529 GFP_KERNEL);
1530 if (!d)
1531 goto err_ret;
1532
1533 closure_init(&d->cl, NULL);
1534 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1535
1536 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1537
1538 if (bcache_device_init(d, block_bytes(c->cache), u->sectors,
1539 NULL, &bcache_flash_ops))
1540 goto err;
1541
1542 bcache_device_attach(d, c, u - c->uuids);
1543 bch_sectors_dirty_init(d);
1544 bch_flash_dev_request_init(d);
1545 err = add_disk(d->disk);
1546 if (err)
1547 goto err;
1548
1549 err = kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache");
1550 if (err)
1551 goto err;
1552
1553 bcache_device_link(d, c, "volume");
1554
1555 if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
1556 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1557 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1558 set_disk_ro(d->disk, 1);
1559 }
1560
1561 return 0;
1562err:
1563 kobject_put(&d->kobj);
1564err_ret:
1565 return err;
1566}
1567
1568static int flash_devs_run(struct cache_set *c)
1569{
1570 int ret = 0;
1571 struct uuid_entry *u;
1572
1573 for (u = c->uuids;
1574 u < c->uuids + c->nr_uuids && !ret;
1575 u++)
1576 if (UUID_FLASH_ONLY(u))
1577 ret = flash_dev_run(c, u);
1578
1579 return ret;
1580}
1581
1582int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1583{
1584 struct uuid_entry *u;
1585
1586 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1587 return -EINTR;
1588
1589 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1590 return -EPERM;
1591
1592 u = uuid_find_empty(c);
1593 if (!u) {
1594 pr_err("Can't create volume, no room for UUID\n");
1595 return -EINVAL;
1596 }
1597
1598 get_random_bytes(u->uuid, 16);
1599 memset(u->label, 0, 32);
1600 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1601
1602 SET_UUID_FLASH_ONLY(u, 1);
1603 u->sectors = size >> 9;
1604
1605 bch_uuid_write(c);
1606
1607 return flash_dev_run(c, u);
1608}
1609
1610bool bch_cached_dev_error(struct cached_dev *dc)
1611{
1612 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1613 return false;
1614
1615 dc->io_disable = true;
1616 /* make others know io_disable is true earlier */
1617 smp_mb();
1618
1619 pr_err("stop %s: too many IO errors on backing device %pg\n",
1620 dc->disk.disk->disk_name, dc->bdev);
1621
1622 bcache_device_stop(&dc->disk);
1623 return true;
1624}
1625
1626/* Cache set */
1627
1628__printf(2, 3)
1629bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1630{
1631 struct va_format vaf;
1632 va_list args;
1633
1634 if (c->on_error != ON_ERROR_PANIC &&
1635 test_bit(CACHE_SET_STOPPING, &c->flags))
1636 return false;
1637
1638 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1639 pr_info("CACHE_SET_IO_DISABLE already set\n");
1640
1641 /*
1642 * XXX: we can be called from atomic context
1643 * acquire_console_sem();
1644 */
1645
1646 va_start(args, fmt);
1647
1648 vaf.fmt = fmt;
1649 vaf.va = &args;
1650
1651 pr_err("error on %pU: %pV, disabling caching\n",
1652 c->set_uuid, &vaf);
1653
1654 va_end(args);
1655
1656 if (c->on_error == ON_ERROR_PANIC)
1657 panic("panic forced after error\n");
1658
1659 bch_cache_set_unregister(c);
1660 return true;
1661}
1662
1663/* When c->kobj released */
1664void bch_cache_set_release(struct kobject *kobj)
1665{
1666 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1667
1668 kfree(c);
1669 module_put(THIS_MODULE);
1670}
1671
1672static void cache_set_free(struct closure *cl)
1673{
1674 struct cache_set *c = container_of(cl, struct cache_set, cl);
1675 struct cache *ca;
1676
1677 debugfs_remove(c->debug);
1678
1679 bch_open_buckets_free(c);
1680 bch_btree_cache_free(c);
1681 bch_journal_free(c);
1682
1683 mutex_lock(&bch_register_lock);
1684 bch_bset_sort_state_free(&c->sort);
1685 free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
1686
1687 ca = c->cache;
1688 if (ca) {
1689 ca->set = NULL;
1690 c->cache = NULL;
1691 kobject_put(&ca->kobj);
1692 }
1693
1694
1695 if (c->moving_gc_wq)
1696 destroy_workqueue(c->moving_gc_wq);
1697 bioset_exit(&c->bio_split);
1698 mempool_exit(&c->fill_iter);
1699 mempool_exit(&c->bio_meta);
1700 mempool_exit(&c->search);
1701 kfree(c->devices);
1702
1703 list_del(&c->list);
1704 mutex_unlock(&bch_register_lock);
1705
1706 pr_info("Cache set %pU unregistered\n", c->set_uuid);
1707 wake_up(&unregister_wait);
1708
1709 closure_debug_destroy(&c->cl);
1710 kobject_put(&c->kobj);
1711}
1712
1713static void cache_set_flush(struct closure *cl)
1714{
1715 struct cache_set *c = container_of(cl, struct cache_set, caching);
1716 struct cache *ca = c->cache;
1717 struct btree *b;
1718
1719 bch_cache_accounting_destroy(&c->accounting);
1720
1721 kobject_put(&c->internal);
1722 kobject_del(&c->kobj);
1723
1724 if (!IS_ERR_OR_NULL(c->gc_thread))
1725 kthread_stop(c->gc_thread);
1726
1727 if (!IS_ERR_OR_NULL(c->root))
1728 list_add(&c->root->list, &c->btree_cache);
1729
1730 /*
1731 * Avoid flushing cached nodes if cache set is retiring
1732 * due to too many I/O errors detected.
1733 */
1734 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1735 list_for_each_entry(b, &c->btree_cache, list) {
1736 mutex_lock(&b->write_lock);
1737 if (btree_node_dirty(b))
1738 __bch_btree_node_write(b, NULL);
1739 mutex_unlock(&b->write_lock);
1740 }
1741
1742 if (ca->alloc_thread)
1743 kthread_stop(ca->alloc_thread);
1744
1745 if (c->journal.cur) {
1746 cancel_delayed_work_sync(&c->journal.work);
1747 /* flush last journal entry if needed */
1748 c->journal.work.work.func(&c->journal.work.work);
1749 }
1750
1751 closure_return(cl);
1752}
1753
1754/*
1755 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1756 * cache set is unregistering due to too many I/O errors. In this condition,
1757 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1758 * value and whether the broken cache has dirty data:
1759 *
1760 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1761 * BCH_CACHED_STOP_AUTO 0 NO
1762 * BCH_CACHED_STOP_AUTO 1 YES
1763 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1764 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1765 *
1766 * The expected behavior is, if stop_when_cache_set_failed is configured to
1767 * "auto" via sysfs interface, the bcache device will not be stopped if the
1768 * backing device is clean on the broken cache device.
1769 */
1770static void conditional_stop_bcache_device(struct cache_set *c,
1771 struct bcache_device *d,
1772 struct cached_dev *dc)
1773{
1774 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1775 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1776 d->disk->disk_name, c->set_uuid);
1777 bcache_device_stop(d);
1778 } else if (atomic_read(&dc->has_dirty)) {
1779 /*
1780 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1781 * and dc->has_dirty == 1
1782 */
1783 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1784 d->disk->disk_name);
1785 /*
1786 * There might be a small time gap that cache set is
1787 * released but bcache device is not. Inside this time
1788 * gap, regular I/O requests will directly go into
1789 * backing device as no cache set attached to. This
1790 * behavior may also introduce potential inconsistence
1791 * data in writeback mode while cache is dirty.
1792 * Therefore before calling bcache_device_stop() due
1793 * to a broken cache device, dc->io_disable should be
1794 * explicitly set to true.
1795 */
1796 dc->io_disable = true;
1797 /* make others know io_disable is true earlier */
1798 smp_mb();
1799 bcache_device_stop(d);
1800 } else {
1801 /*
1802 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1803 * and dc->has_dirty == 0
1804 */
1805 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1806 d->disk->disk_name);
1807 }
1808}
1809
1810static void __cache_set_unregister(struct closure *cl)
1811{
1812 struct cache_set *c = container_of(cl, struct cache_set, caching);
1813 struct cached_dev *dc;
1814 struct bcache_device *d;
1815 size_t i;
1816
1817 mutex_lock(&bch_register_lock);
1818
1819 for (i = 0; i < c->devices_max_used; i++) {
1820 d = c->devices[i];
1821 if (!d)
1822 continue;
1823
1824 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1825 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1826 dc = container_of(d, struct cached_dev, disk);
1827 bch_cached_dev_detach(dc);
1828 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1829 conditional_stop_bcache_device(c, d, dc);
1830 } else {
1831 bcache_device_stop(d);
1832 }
1833 }
1834
1835 mutex_unlock(&bch_register_lock);
1836
1837 continue_at(cl, cache_set_flush, system_wq);
1838}
1839
1840void bch_cache_set_stop(struct cache_set *c)
1841{
1842 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1843 /* closure_fn set to __cache_set_unregister() */
1844 closure_queue(&c->caching);
1845}
1846
1847void bch_cache_set_unregister(struct cache_set *c)
1848{
1849 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1850 bch_cache_set_stop(c);
1851}
1852
1853#define alloc_meta_bucket_pages(gfp, sb) \
1854 ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1855
1856struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1857{
1858 int iter_size;
1859 struct cache *ca = container_of(sb, struct cache, sb);
1860 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1861
1862 if (!c)
1863 return NULL;
1864
1865 __module_get(THIS_MODULE);
1866 closure_init(&c->cl, NULL);
1867 set_closure_fn(&c->cl, cache_set_free, system_wq);
1868
1869 closure_init(&c->caching, &c->cl);
1870 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1871
1872 /* Maybe create continue_at_noreturn() and use it here? */
1873 closure_set_stopped(&c->cl);
1874 closure_put(&c->cl);
1875
1876 kobject_init(&c->kobj, &bch_cache_set_ktype);
1877 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1878
1879 bch_cache_accounting_init(&c->accounting, &c->cl);
1880
1881 memcpy(c->set_uuid, sb->set_uuid, 16);
1882
1883 c->cache = ca;
1884 c->cache->set = c;
1885 c->bucket_bits = ilog2(sb->bucket_size);
1886 c->block_bits = ilog2(sb->block_size);
1887 c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
1888 c->devices_max_used = 0;
1889 atomic_set(&c->attached_dev_nr, 0);
1890 c->btree_pages = meta_bucket_pages(sb);
1891 if (c->btree_pages > BTREE_MAX_PAGES)
1892 c->btree_pages = max_t(int, c->btree_pages / 4,
1893 BTREE_MAX_PAGES);
1894
1895 sema_init(&c->sb_write_mutex, 1);
1896 mutex_init(&c->bucket_lock);
1897 init_waitqueue_head(&c->btree_cache_wait);
1898 spin_lock_init(&c->btree_cannibalize_lock);
1899 init_waitqueue_head(&c->bucket_wait);
1900 init_waitqueue_head(&c->gc_wait);
1901 sema_init(&c->uuid_write_mutex, 1);
1902
1903 spin_lock_init(&c->btree_gc_time.lock);
1904 spin_lock_init(&c->btree_split_time.lock);
1905 spin_lock_init(&c->btree_read_time.lock);
1906
1907 bch_moving_init_cache_set(c);
1908
1909 INIT_LIST_HEAD(&c->list);
1910 INIT_LIST_HEAD(&c->cached_devs);
1911 INIT_LIST_HEAD(&c->btree_cache);
1912 INIT_LIST_HEAD(&c->btree_cache_freeable);
1913 INIT_LIST_HEAD(&c->btree_cache_freed);
1914 INIT_LIST_HEAD(&c->data_buckets);
1915
1916 iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
1917 sizeof(struct btree_iter_set);
1918
1919 c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1920 if (!c->devices)
1921 goto err;
1922
1923 if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1924 goto err;
1925
1926 if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1927 sizeof(struct bbio) +
1928 sizeof(struct bio_vec) * meta_bucket_pages(sb)))
1929 goto err;
1930
1931 if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1932 goto err;
1933
1934 if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1935 BIOSET_NEED_RESCUER))
1936 goto err;
1937
1938 c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
1939 if (!c->uuids)
1940 goto err;
1941
1942 c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
1943 if (!c->moving_gc_wq)
1944 goto err;
1945
1946 if (bch_journal_alloc(c))
1947 goto err;
1948
1949 if (bch_btree_cache_alloc(c))
1950 goto err;
1951
1952 if (bch_open_buckets_alloc(c))
1953 goto err;
1954
1955 if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1956 goto err;
1957
1958 c->congested_read_threshold_us = 2000;
1959 c->congested_write_threshold_us = 20000;
1960 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1961 c->idle_max_writeback_rate_enabled = 1;
1962 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1963
1964 return c;
1965err:
1966 bch_cache_set_unregister(c);
1967 return NULL;
1968}
1969
1970static int run_cache_set(struct cache_set *c)
1971{
1972 const char *err = "cannot allocate memory";
1973 struct cached_dev *dc, *t;
1974 struct cache *ca = c->cache;
1975 struct closure cl;
1976 LIST_HEAD(journal);
1977 struct journal_replay *l;
1978
1979 closure_init_stack(&cl);
1980
1981 c->nbuckets = ca->sb.nbuckets;
1982 set_gc_sectors(c);
1983
1984 if (CACHE_SYNC(&c->cache->sb)) {
1985 struct bkey *k;
1986 struct jset *j;
1987
1988 err = "cannot allocate memory for journal";
1989 if (bch_journal_read(c, &journal))
1990 goto err;
1991
1992 pr_debug("btree_journal_read() done\n");
1993
1994 err = "no journal entries found";
1995 if (list_empty(&journal))
1996 goto err;
1997
1998 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1999
2000 err = "IO error reading priorities";
2001 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2002 goto err;
2003
2004 /*
2005 * If prio_read() fails it'll call cache_set_error and we'll
2006 * tear everything down right away, but if we perhaps checked
2007 * sooner we could avoid journal replay.
2008 */
2009
2010 k = &j->btree_root;
2011
2012 err = "bad btree root";
2013 if (__bch_btree_ptr_invalid(c, k))
2014 goto err;
2015
2016 err = "error reading btree root";
2017 c->root = bch_btree_node_get(c, NULL, k,
2018 j->btree_level,
2019 true, NULL);
2020 if (IS_ERR_OR_NULL(c->root))
2021 goto err;
2022
2023 list_del_init(&c->root->list);
2024 rw_unlock(true, c->root);
2025
2026 err = uuid_read(c, j, &cl);
2027 if (err)
2028 goto err;
2029
2030 err = "error in recovery";
2031 if (bch_btree_check(c))
2032 goto err;
2033
2034 bch_journal_mark(c, &journal);
2035 bch_initial_gc_finish(c);
2036 pr_debug("btree_check() done\n");
2037
2038 /*
2039 * bcache_journal_next() can't happen sooner, or
2040 * btree_gc_finish() will give spurious errors about last_gc >
2041 * gc_gen - this is a hack but oh well.
2042 */
2043 bch_journal_next(&c->journal);
2044
2045 err = "error starting allocator thread";
2046 if (bch_cache_allocator_start(ca))
2047 goto err;
2048
2049 /*
2050 * First place it's safe to allocate: btree_check() and
2051 * btree_gc_finish() have to run before we have buckets to
2052 * allocate, and bch_bucket_alloc_set() might cause a journal
2053 * entry to be written so bcache_journal_next() has to be called
2054 * first.
2055 *
2056 * If the uuids were in the old format we have to rewrite them
2057 * before the next journal entry is written:
2058 */
2059 if (j->version < BCACHE_JSET_VERSION_UUID)
2060 __uuid_write(c);
2061
2062 err = "bcache: replay journal failed";
2063 if (bch_journal_replay(c, &journal))
2064 goto err;
2065 } else {
2066 unsigned int j;
2067
2068 pr_notice("invalidating existing data\n");
2069 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2070 2, SB_JOURNAL_BUCKETS);
2071
2072 for (j = 0; j < ca->sb.keys; j++)
2073 ca->sb.d[j] = ca->sb.first_bucket + j;
2074
2075 bch_initial_gc_finish(c);
2076
2077 err = "error starting allocator thread";
2078 if (bch_cache_allocator_start(ca))
2079 goto err;
2080
2081 mutex_lock(&c->bucket_lock);
2082 bch_prio_write(ca, true);
2083 mutex_unlock(&c->bucket_lock);
2084
2085 err = "cannot allocate new UUID bucket";
2086 if (__uuid_write(c))
2087 goto err;
2088
2089 err = "cannot allocate new btree root";
2090 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2091 if (IS_ERR_OR_NULL(c->root))
2092 goto err;
2093
2094 mutex_lock(&c->root->write_lock);
2095 bkey_copy_key(&c->root->key, &MAX_KEY);
2096 bch_btree_node_write(c->root, &cl);
2097 mutex_unlock(&c->root->write_lock);
2098
2099 bch_btree_set_root(c->root);
2100 rw_unlock(true, c->root);
2101
2102 /*
2103 * We don't want to write the first journal entry until
2104 * everything is set up - fortunately journal entries won't be
2105 * written until the SET_CACHE_SYNC() here:
2106 */
2107 SET_CACHE_SYNC(&c->cache->sb, true);
2108
2109 bch_journal_next(&c->journal);
2110 bch_journal_meta(c, &cl);
2111 }
2112
2113 err = "error starting gc thread";
2114 if (bch_gc_thread_start(c))
2115 goto err;
2116
2117 closure_sync(&cl);
2118 c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
2119 bcache_write_super(c);
2120
2121 if (bch_has_feature_obso_large_bucket(&c->cache->sb))
2122 pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
2123
2124 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2125 bch_cached_dev_attach(dc, c, NULL);
2126
2127 flash_devs_run(c);
2128
2129 bch_journal_space_reserve(&c->journal);
2130 set_bit(CACHE_SET_RUNNING, &c->flags);
2131 return 0;
2132err:
2133 while (!list_empty(&journal)) {
2134 l = list_first_entry(&journal, struct journal_replay, list);
2135 list_del(&l->list);
2136 kfree(l);
2137 }
2138
2139 closure_sync(&cl);
2140
2141 bch_cache_set_error(c, "%s", err);
2142
2143 return -EIO;
2144}
2145
2146static const char *register_cache_set(struct cache *ca)
2147{
2148 char buf[12];
2149 const char *err = "cannot allocate memory";
2150 struct cache_set *c;
2151
2152 list_for_each_entry(c, &bch_cache_sets, list)
2153 if (!memcmp(c->set_uuid, ca->sb.set_uuid, 16)) {
2154 if (c->cache)
2155 return "duplicate cache set member";
2156
2157 goto found;
2158 }
2159
2160 c = bch_cache_set_alloc(&ca->sb);
2161 if (!c)
2162 return err;
2163
2164 err = "error creating kobject";
2165 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->set_uuid) ||
2166 kobject_add(&c->internal, &c->kobj, "internal"))
2167 goto err;
2168
2169 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2170 goto err;
2171
2172 bch_debug_init_cache_set(c);
2173
2174 list_add(&c->list, &bch_cache_sets);
2175found:
2176 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2177 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2178 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2179 goto err;
2180
2181 kobject_get(&ca->kobj);
2182 ca->set = c;
2183 ca->set->cache = ca;
2184
2185 err = "failed to run cache set";
2186 if (run_cache_set(c) < 0)
2187 goto err;
2188
2189 return NULL;
2190err:
2191 bch_cache_set_unregister(c);
2192 return err;
2193}
2194
2195/* Cache device */
2196
2197/* When ca->kobj released */
2198void bch_cache_release(struct kobject *kobj)
2199{
2200 struct cache *ca = container_of(kobj, struct cache, kobj);
2201 unsigned int i;
2202
2203 if (ca->set) {
2204 BUG_ON(ca->set->cache != ca);
2205 ca->set->cache = NULL;
2206 }
2207
2208 free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2209 kfree(ca->prio_buckets);
2210 vfree(ca->buckets);
2211
2212 free_heap(&ca->heap);
2213 free_fifo(&ca->free_inc);
2214
2215 for (i = 0; i < RESERVE_NR; i++)
2216 free_fifo(&ca->free[i]);
2217
2218 if (ca->sb_disk)
2219 put_page(virt_to_page(ca->sb_disk));
2220
2221 if (!IS_ERR_OR_NULL(ca->bdev))
2222 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2223
2224 kfree(ca);
2225 module_put(THIS_MODULE);
2226}
2227
2228static int cache_alloc(struct cache *ca)
2229{
2230 size_t free;
2231 size_t btree_buckets;
2232 struct bucket *b;
2233 int ret = -ENOMEM;
2234 const char *err = NULL;
2235
2236 __module_get(THIS_MODULE);
2237 kobject_init(&ca->kobj, &bch_cache_ktype);
2238
2239 bio_init(&ca->journal.bio, NULL, ca->journal.bio.bi_inline_vecs, 8, 0);
2240
2241 /*
2242 * when ca->sb.njournal_buckets is not zero, journal exists,
2243 * and in bch_journal_replay(), tree node may split,
2244 * so bucket of RESERVE_BTREE type is needed,
2245 * the worst situation is all journal buckets are valid journal,
2246 * and all the keys need to replay,
2247 * so the number of RESERVE_BTREE type buckets should be as much
2248 * as journal buckets
2249 */
2250 btree_buckets = ca->sb.njournal_buckets ?: 8;
2251 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2252 if (!free) {
2253 ret = -EPERM;
2254 err = "ca->sb.nbuckets is too small";
2255 goto err_free;
2256 }
2257
2258 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2259 GFP_KERNEL)) {
2260 err = "ca->free[RESERVE_BTREE] alloc failed";
2261 goto err_btree_alloc;
2262 }
2263
2264 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2265 GFP_KERNEL)) {
2266 err = "ca->free[RESERVE_PRIO] alloc failed";
2267 goto err_prio_alloc;
2268 }
2269
2270 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2271 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2272 goto err_movinggc_alloc;
2273 }
2274
2275 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2276 err = "ca->free[RESERVE_NONE] alloc failed";
2277 goto err_none_alloc;
2278 }
2279
2280 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2281 err = "ca->free_inc alloc failed";
2282 goto err_free_inc_alloc;
2283 }
2284
2285 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2286 err = "ca->heap alloc failed";
2287 goto err_heap_alloc;
2288 }
2289
2290 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2291 ca->sb.nbuckets));
2292 if (!ca->buckets) {
2293 err = "ca->buckets alloc failed";
2294 goto err_buckets_alloc;
2295 }
2296
2297 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2298 prio_buckets(ca), 2),
2299 GFP_KERNEL);
2300 if (!ca->prio_buckets) {
2301 err = "ca->prio_buckets alloc failed";
2302 goto err_prio_buckets_alloc;
2303 }
2304
2305 ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2306 if (!ca->disk_buckets) {
2307 err = "ca->disk_buckets alloc failed";
2308 goto err_disk_buckets_alloc;
2309 }
2310
2311 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2312
2313 for_each_bucket(b, ca)
2314 atomic_set(&b->pin, 0);
2315 return 0;
2316
2317err_disk_buckets_alloc:
2318 kfree(ca->prio_buckets);
2319err_prio_buckets_alloc:
2320 vfree(ca->buckets);
2321err_buckets_alloc:
2322 free_heap(&ca->heap);
2323err_heap_alloc:
2324 free_fifo(&ca->free_inc);
2325err_free_inc_alloc:
2326 free_fifo(&ca->free[RESERVE_NONE]);
2327err_none_alloc:
2328 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2329err_movinggc_alloc:
2330 free_fifo(&ca->free[RESERVE_PRIO]);
2331err_prio_alloc:
2332 free_fifo(&ca->free[RESERVE_BTREE]);
2333err_btree_alloc:
2334err_free:
2335 module_put(THIS_MODULE);
2336 if (err)
2337 pr_notice("error %pg: %s\n", ca->bdev, err);
2338 return ret;
2339}
2340
2341static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2342 struct block_device *bdev, struct cache *ca)
2343{
2344 const char *err = NULL; /* must be set for any error case */
2345 int ret = 0;
2346
2347 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2348 ca->bdev = bdev;
2349 ca->bdev->bd_holder = ca;
2350 ca->sb_disk = sb_disk;
2351
2352 if (bdev_max_discard_sectors((bdev)))
2353 ca->discard = CACHE_DISCARD(&ca->sb);
2354
2355 ret = cache_alloc(ca);
2356 if (ret != 0) {
2357 /*
2358 * If we failed here, it means ca->kobj is not initialized yet,
2359 * kobject_put() won't be called and there is no chance to
2360 * call blkdev_put() to bdev in bch_cache_release(). So we
2361 * explicitly call blkdev_put() here.
2362 */
2363 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2364 if (ret == -ENOMEM)
2365 err = "cache_alloc(): -ENOMEM";
2366 else if (ret == -EPERM)
2367 err = "cache_alloc(): cache device is too small";
2368 else
2369 err = "cache_alloc(): unknown error";
2370 goto err;
2371 }
2372
2373 if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) {
2374 err = "error calling kobject_add";
2375 ret = -ENOMEM;
2376 goto out;
2377 }
2378
2379 mutex_lock(&bch_register_lock);
2380 err = register_cache_set(ca);
2381 mutex_unlock(&bch_register_lock);
2382
2383 if (err) {
2384 ret = -ENODEV;
2385 goto out;
2386 }
2387
2388 pr_info("registered cache device %pg\n", ca->bdev);
2389
2390out:
2391 kobject_put(&ca->kobj);
2392
2393err:
2394 if (err)
2395 pr_notice("error %pg: %s\n", ca->bdev, err);
2396
2397 return ret;
2398}
2399
2400/* Global interfaces/init */
2401
2402static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2403 const char *buffer, size_t size);
2404static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2405 struct kobj_attribute *attr,
2406 const char *buffer, size_t size);
2407
2408kobj_attribute_write(register, register_bcache);
2409kobj_attribute_write(register_quiet, register_bcache);
2410kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2411
2412static bool bch_is_open_backing(dev_t dev)
2413{
2414 struct cache_set *c, *tc;
2415 struct cached_dev *dc, *t;
2416
2417 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2418 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2419 if (dc->bdev->bd_dev == dev)
2420 return true;
2421 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2422 if (dc->bdev->bd_dev == dev)
2423 return true;
2424 return false;
2425}
2426
2427static bool bch_is_open_cache(dev_t dev)
2428{
2429 struct cache_set *c, *tc;
2430
2431 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2432 struct cache *ca = c->cache;
2433
2434 if (ca->bdev->bd_dev == dev)
2435 return true;
2436 }
2437
2438 return false;
2439}
2440
2441static bool bch_is_open(dev_t dev)
2442{
2443 return bch_is_open_cache(dev) || bch_is_open_backing(dev);
2444}
2445
2446struct async_reg_args {
2447 struct delayed_work reg_work;
2448 char *path;
2449 struct cache_sb *sb;
2450 struct cache_sb_disk *sb_disk;
2451 struct block_device *bdev;
2452};
2453
2454static void register_bdev_worker(struct work_struct *work)
2455{
2456 int fail = false;
2457 struct async_reg_args *args =
2458 container_of(work, struct async_reg_args, reg_work.work);
2459 struct cached_dev *dc;
2460
2461 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2462 if (!dc) {
2463 fail = true;
2464 put_page(virt_to_page(args->sb_disk));
2465 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2466 goto out;
2467 }
2468
2469 mutex_lock(&bch_register_lock);
2470 if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
2471 fail = true;
2472 mutex_unlock(&bch_register_lock);
2473
2474out:
2475 if (fail)
2476 pr_info("error %s: fail to register backing device\n",
2477 args->path);
2478 kfree(args->sb);
2479 kfree(args->path);
2480 kfree(args);
2481 module_put(THIS_MODULE);
2482}
2483
2484static void register_cache_worker(struct work_struct *work)
2485{
2486 int fail = false;
2487 struct async_reg_args *args =
2488 container_of(work, struct async_reg_args, reg_work.work);
2489 struct cache *ca;
2490
2491 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2492 if (!ca) {
2493 fail = true;
2494 put_page(virt_to_page(args->sb_disk));
2495 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2496 goto out;
2497 }
2498
2499 /* blkdev_put() will be called in bch_cache_release() */
2500 if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
2501 fail = true;
2502
2503out:
2504 if (fail)
2505 pr_info("error %s: fail to register cache device\n",
2506 args->path);
2507 kfree(args->sb);
2508 kfree(args->path);
2509 kfree(args);
2510 module_put(THIS_MODULE);
2511}
2512
2513static void register_device_async(struct async_reg_args *args)
2514{
2515 if (SB_IS_BDEV(args->sb))
2516 INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2517 else
2518 INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2519
2520 /* 10 jiffies is enough for a delay */
2521 queue_delayed_work(system_wq, &args->reg_work, 10);
2522}
2523
2524static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2525 const char *buffer, size_t size)
2526{
2527 const char *err;
2528 char *path = NULL;
2529 struct cache_sb *sb;
2530 struct cache_sb_disk *sb_disk;
2531 struct block_device *bdev;
2532 ssize_t ret;
2533 bool async_registration = false;
2534
2535#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2536 async_registration = true;
2537#endif
2538
2539 ret = -EBUSY;
2540 err = "failed to reference bcache module";
2541 if (!try_module_get(THIS_MODULE))
2542 goto out;
2543
2544 /* For latest state of bcache_is_reboot */
2545 smp_mb();
2546 err = "bcache is in reboot";
2547 if (bcache_is_reboot)
2548 goto out_module_put;
2549
2550 ret = -ENOMEM;
2551 err = "cannot allocate memory";
2552 path = kstrndup(buffer, size, GFP_KERNEL);
2553 if (!path)
2554 goto out_module_put;
2555
2556 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2557 if (!sb)
2558 goto out_free_path;
2559
2560 ret = -EINVAL;
2561 err = "failed to open device";
2562 bdev = blkdev_get_by_path(strim(path),
2563 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2564 sb);
2565 if (IS_ERR(bdev)) {
2566 if (bdev == ERR_PTR(-EBUSY)) {
2567 dev_t dev;
2568
2569 mutex_lock(&bch_register_lock);
2570 if (lookup_bdev(strim(path), &dev) == 0 &&
2571 bch_is_open(dev))
2572 err = "device already registered";
2573 else
2574 err = "device busy";
2575 mutex_unlock(&bch_register_lock);
2576 if (attr == &ksysfs_register_quiet)
2577 goto done;
2578 }
2579 goto out_free_sb;
2580 }
2581
2582 err = "failed to set blocksize";
2583 if (set_blocksize(bdev, 4096))
2584 goto out_blkdev_put;
2585
2586 err = read_super(sb, bdev, &sb_disk);
2587 if (err)
2588 goto out_blkdev_put;
2589
2590 err = "failed to register device";
2591
2592 if (async_registration) {
2593 /* register in asynchronous way */
2594 struct async_reg_args *args =
2595 kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2596
2597 if (!args) {
2598 ret = -ENOMEM;
2599 err = "cannot allocate memory";
2600 goto out_put_sb_page;
2601 }
2602
2603 args->path = path;
2604 args->sb = sb;
2605 args->sb_disk = sb_disk;
2606 args->bdev = bdev;
2607 register_device_async(args);
2608 /* No wait and returns to user space */
2609 goto async_done;
2610 }
2611
2612 if (SB_IS_BDEV(sb)) {
2613 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2614
2615 if (!dc) {
2616 ret = -ENOMEM;
2617 err = "cannot allocate memory";
2618 goto out_put_sb_page;
2619 }
2620
2621 mutex_lock(&bch_register_lock);
2622 ret = register_bdev(sb, sb_disk, bdev, dc);
2623 mutex_unlock(&bch_register_lock);
2624 /* blkdev_put() will be called in cached_dev_free() */
2625 if (ret < 0)
2626 goto out_free_sb;
2627 } else {
2628 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2629
2630 if (!ca) {
2631 ret = -ENOMEM;
2632 err = "cannot allocate memory";
2633 goto out_put_sb_page;
2634 }
2635
2636 /* blkdev_put() will be called in bch_cache_release() */
2637 ret = register_cache(sb, sb_disk, bdev, ca);
2638 if (ret)
2639 goto out_free_sb;
2640 }
2641
2642done:
2643 kfree(sb);
2644 kfree(path);
2645 module_put(THIS_MODULE);
2646async_done:
2647 return size;
2648
2649out_put_sb_page:
2650 put_page(virt_to_page(sb_disk));
2651out_blkdev_put:
2652 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2653out_free_sb:
2654 kfree(sb);
2655out_free_path:
2656 kfree(path);
2657 path = NULL;
2658out_module_put:
2659 module_put(THIS_MODULE);
2660out:
2661 pr_info("error %s: %s\n", path?path:"", err);
2662 return ret;
2663}
2664
2665
2666struct pdev {
2667 struct list_head list;
2668 struct cached_dev *dc;
2669};
2670
2671static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2672 struct kobj_attribute *attr,
2673 const char *buffer,
2674 size_t size)
2675{
2676 LIST_HEAD(pending_devs);
2677 ssize_t ret = size;
2678 struct cached_dev *dc, *tdc;
2679 struct pdev *pdev, *tpdev;
2680 struct cache_set *c, *tc;
2681
2682 mutex_lock(&bch_register_lock);
2683 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2684 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2685 if (!pdev)
2686 break;
2687 pdev->dc = dc;
2688 list_add(&pdev->list, &pending_devs);
2689 }
2690
2691 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2692 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2693 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2694 char *set_uuid = c->set_uuid;
2695
2696 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2697 list_del(&pdev->list);
2698 kfree(pdev);
2699 break;
2700 }
2701 }
2702 }
2703 mutex_unlock(&bch_register_lock);
2704
2705 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2706 pr_info("delete pdev %p\n", pdev);
2707 list_del(&pdev->list);
2708 bcache_device_stop(&pdev->dc->disk);
2709 kfree(pdev);
2710 }
2711
2712 return ret;
2713}
2714
2715static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2716{
2717 if (bcache_is_reboot)
2718 return NOTIFY_DONE;
2719
2720 if (code == SYS_DOWN ||
2721 code == SYS_HALT ||
2722 code == SYS_POWER_OFF) {
2723 DEFINE_WAIT(wait);
2724 unsigned long start = jiffies;
2725 bool stopped = false;
2726
2727 struct cache_set *c, *tc;
2728 struct cached_dev *dc, *tdc;
2729
2730 mutex_lock(&bch_register_lock);
2731
2732 if (bcache_is_reboot)
2733 goto out;
2734
2735 /* New registration is rejected since now */
2736 bcache_is_reboot = true;
2737 /*
2738 * Make registering caller (if there is) on other CPU
2739 * core know bcache_is_reboot set to true earlier
2740 */
2741 smp_mb();
2742
2743 if (list_empty(&bch_cache_sets) &&
2744 list_empty(&uncached_devices))
2745 goto out;
2746
2747 mutex_unlock(&bch_register_lock);
2748
2749 pr_info("Stopping all devices:\n");
2750
2751 /*
2752 * The reason bch_register_lock is not held to call
2753 * bch_cache_set_stop() and bcache_device_stop() is to
2754 * avoid potential deadlock during reboot, because cache
2755 * set or bcache device stopping process will acquire
2756 * bch_register_lock too.
2757 *
2758 * We are safe here because bcache_is_reboot sets to
2759 * true already, register_bcache() will reject new
2760 * registration now. bcache_is_reboot also makes sure
2761 * bcache_reboot() won't be re-entered on by other thread,
2762 * so there is no race in following list iteration by
2763 * list_for_each_entry_safe().
2764 */
2765 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2766 bch_cache_set_stop(c);
2767
2768 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2769 bcache_device_stop(&dc->disk);
2770
2771
2772 /*
2773 * Give an early chance for other kthreads and
2774 * kworkers to stop themselves
2775 */
2776 schedule();
2777
2778 /* What's a condition variable? */
2779 while (1) {
2780 long timeout = start + 10 * HZ - jiffies;
2781
2782 mutex_lock(&bch_register_lock);
2783 stopped = list_empty(&bch_cache_sets) &&
2784 list_empty(&uncached_devices);
2785
2786 if (timeout < 0 || stopped)
2787 break;
2788
2789 prepare_to_wait(&unregister_wait, &wait,
2790 TASK_UNINTERRUPTIBLE);
2791
2792 mutex_unlock(&bch_register_lock);
2793 schedule_timeout(timeout);
2794 }
2795
2796 finish_wait(&unregister_wait, &wait);
2797
2798 if (stopped)
2799 pr_info("All devices stopped\n");
2800 else
2801 pr_notice("Timeout waiting for devices to be closed\n");
2802out:
2803 mutex_unlock(&bch_register_lock);
2804 }
2805
2806 return NOTIFY_DONE;
2807}
2808
2809static struct notifier_block reboot = {
2810 .notifier_call = bcache_reboot,
2811 .priority = INT_MAX, /* before any real devices */
2812};
2813
2814static void bcache_exit(void)
2815{
2816 bch_debug_exit();
2817 bch_request_exit();
2818 if (bcache_kobj)
2819 kobject_put(bcache_kobj);
2820 if (bcache_wq)
2821 destroy_workqueue(bcache_wq);
2822 if (bch_journal_wq)
2823 destroy_workqueue(bch_journal_wq);
2824 if (bch_flush_wq)
2825 destroy_workqueue(bch_flush_wq);
2826 bch_btree_exit();
2827
2828 if (bcache_major)
2829 unregister_blkdev(bcache_major, "bcache");
2830 unregister_reboot_notifier(&reboot);
2831 mutex_destroy(&bch_register_lock);
2832}
2833
2834/* Check and fixup module parameters */
2835static void check_module_parameters(void)
2836{
2837 if (bch_cutoff_writeback_sync == 0)
2838 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2839 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2840 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2841 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2842 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2843 }
2844
2845 if (bch_cutoff_writeback == 0)
2846 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2847 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2848 pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2849 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2850 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2851 }
2852
2853 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2854 pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2855 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2856 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2857 }
2858}
2859
2860static int __init bcache_init(void)
2861{
2862 static const struct attribute *files[] = {
2863 &ksysfs_register.attr,
2864 &ksysfs_register_quiet.attr,
2865 &ksysfs_pendings_cleanup.attr,
2866 NULL
2867 };
2868
2869 check_module_parameters();
2870
2871 mutex_init(&bch_register_lock);
2872 init_waitqueue_head(&unregister_wait);
2873 register_reboot_notifier(&reboot);
2874
2875 bcache_major = register_blkdev(0, "bcache");
2876 if (bcache_major < 0) {
2877 unregister_reboot_notifier(&reboot);
2878 mutex_destroy(&bch_register_lock);
2879 return bcache_major;
2880 }
2881
2882 if (bch_btree_init())
2883 goto err;
2884
2885 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2886 if (!bcache_wq)
2887 goto err;
2888
2889 /*
2890 * Let's not make this `WQ_MEM_RECLAIM` for the following reasons:
2891 *
2892 * 1. It used `system_wq` before which also does no memory reclaim.
2893 * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and
2894 * reduced throughput can be observed.
2895 *
2896 * We still want to user our own queue to not congest the `system_wq`.
2897 */
2898 bch_flush_wq = alloc_workqueue("bch_flush", 0, 0);
2899 if (!bch_flush_wq)
2900 goto err;
2901
2902 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2903 if (!bch_journal_wq)
2904 goto err;
2905
2906 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2907 if (!bcache_kobj)
2908 goto err;
2909
2910 if (bch_request_init() ||
2911 sysfs_create_files(bcache_kobj, files))
2912 goto err;
2913
2914 bch_debug_init();
2915 closure_debug_init();
2916
2917 bcache_is_reboot = false;
2918
2919 return 0;
2920err:
2921 bcache_exit();
2922 return -ENOMEM;
2923}
2924
2925/*
2926 * Module hooks
2927 */
2928module_exit(bcache_exit);
2929module_init(bcache_init);
2930
2931module_param(bch_cutoff_writeback, uint, 0);
2932MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2933
2934module_param(bch_cutoff_writeback_sync, uint, 0);
2935MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2936
2937MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2938MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2939MODULE_LICENSE("GPL");
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 <kent.overstreet@gmail.com>
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 page *page;
172 unsigned int i;
173
174 page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
175 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
176 if (IS_ERR(page))
177 return "IO error";
178 s = page_address(page) + offset_in_page(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 put_page(page);
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_page(bio, virt_to_page(out), SB_SIZE,
297 offset_in_page(out));
298
299 out->offset = cpu_to_le64(sb->offset);
300
301 memcpy(out->uuid, sb->uuid, 16);
302 memcpy(out->set_uuid, sb->set_uuid, 16);
303 memcpy(out->label, sb->label, SB_LABEL_SIZE);
304
305 out->flags = cpu_to_le64(sb->flags);
306 out->seq = cpu_to_le64(sb->seq);
307
308 out->last_mount = cpu_to_le32(sb->last_mount);
309 out->first_bucket = cpu_to_le16(sb->first_bucket);
310 out->keys = cpu_to_le16(sb->keys);
311
312 for (i = 0; i < sb->keys; i++)
313 out->d[i] = cpu_to_le64(sb->d[i]);
314
315 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
316 out->feature_compat = cpu_to_le64(sb->feature_compat);
317 out->feature_incompat = cpu_to_le64(sb->feature_incompat);
318 out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
319 }
320
321 out->version = cpu_to_le64(sb->version);
322 out->csum = csum_set(out);
323
324 pr_debug("ver %llu, flags %llu, seq %llu\n",
325 sb->version, sb->flags, sb->seq);
326
327 submit_bio(bio);
328}
329
330static CLOSURE_CALLBACK(bch_write_bdev_super_unlock)
331{
332 closure_type(dc, struct cached_dev, sb_write);
333
334 up(&dc->sb_write_mutex);
335}
336
337void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
338{
339 struct closure *cl = &dc->sb_write;
340 struct bio *bio = &dc->sb_bio;
341
342 down(&dc->sb_write_mutex);
343 closure_init(cl, parent);
344
345 bio_init(bio, dc->bdev, dc->sb_bv, 1, 0);
346 bio->bi_end_io = write_bdev_super_endio;
347 bio->bi_private = dc;
348
349 closure_get(cl);
350 /* I/O request sent to backing device */
351 __write_super(&dc->sb, dc->sb_disk, bio);
352
353 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
354}
355
356static void write_super_endio(struct bio *bio)
357{
358 struct cache *ca = bio->bi_private;
359
360 /* is_read = 0 */
361 bch_count_io_errors(ca, bio->bi_status, 0,
362 "writing superblock");
363 closure_put(&ca->set->sb_write);
364}
365
366static CLOSURE_CALLBACK(bcache_write_super_unlock)
367{
368 closure_type(c, struct cache_set, sb_write);
369
370 up(&c->sb_write_mutex);
371}
372
373void bcache_write_super(struct cache_set *c)
374{
375 struct closure *cl = &c->sb_write;
376 struct cache *ca = c->cache;
377 struct bio *bio = &ca->sb_bio;
378 unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
379
380 down(&c->sb_write_mutex);
381 closure_init(cl, &c->cl);
382
383 ca->sb.seq++;
384
385 if (ca->sb.version < version)
386 ca->sb.version = version;
387
388 bio_init(bio, ca->bdev, ca->sb_bv, 1, 0);
389 bio->bi_end_io = write_super_endio;
390 bio->bi_private = ca;
391
392 closure_get(cl);
393 __write_super(&ca->sb, ca->sb_disk, bio);
394
395 closure_return_with_destructor(cl, bcache_write_super_unlock);
396}
397
398/* UUID io */
399
400static void uuid_endio(struct bio *bio)
401{
402 struct closure *cl = bio->bi_private;
403 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
404
405 cache_set_err_on(bio->bi_status, c, "accessing uuids");
406 bch_bbio_free(bio, c);
407 closure_put(cl);
408}
409
410static CLOSURE_CALLBACK(uuid_io_unlock)
411{
412 closure_type(c, struct cache_set, uuid_write);
413
414 up(&c->uuid_write_mutex);
415}
416
417static void uuid_io(struct cache_set *c, blk_opf_t opf, struct bkey *k,
418 struct closure *parent)
419{
420 struct closure *cl = &c->uuid_write;
421 struct uuid_entry *u;
422 unsigned int i;
423 char buf[80];
424
425 BUG_ON(!parent);
426 down(&c->uuid_write_mutex);
427 closure_init(cl, parent);
428
429 for (i = 0; i < KEY_PTRS(k); i++) {
430 struct bio *bio = bch_bbio_alloc(c);
431
432 bio->bi_opf = opf | REQ_SYNC | REQ_META;
433 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
434
435 bio->bi_end_io = uuid_endio;
436 bio->bi_private = cl;
437 bch_bio_map(bio, c->uuids);
438
439 bch_submit_bbio(bio, c, k, i);
440
441 if ((opf & REQ_OP_MASK) != REQ_OP_WRITE)
442 break;
443 }
444
445 bch_extent_to_text(buf, sizeof(buf), k);
446 pr_debug("%s UUIDs at %s\n", (opf & REQ_OP_MASK) == REQ_OP_WRITE ?
447 "wrote" : "read", buf);
448
449 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
450 if (!bch_is_zero(u->uuid, 16))
451 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
452 u - c->uuids, u->uuid, u->label,
453 u->first_reg, u->last_reg, u->invalidated);
454
455 closure_return_with_destructor(cl, uuid_io_unlock);
456}
457
458static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
459{
460 struct bkey *k = &j->uuid_bucket;
461
462 if (__bch_btree_ptr_invalid(c, k))
463 return "bad uuid pointer";
464
465 bkey_copy(&c->uuid_bucket, k);
466 uuid_io(c, REQ_OP_READ, k, cl);
467
468 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
469 struct uuid_entry_v0 *u0 = (void *) c->uuids;
470 struct uuid_entry *u1 = (void *) c->uuids;
471 int i;
472
473 closure_sync(cl);
474
475 /*
476 * Since the new uuid entry is bigger than the old, we have to
477 * convert starting at the highest memory address and work down
478 * in order to do it in place
479 */
480
481 for (i = c->nr_uuids - 1;
482 i >= 0;
483 --i) {
484 memcpy(u1[i].uuid, u0[i].uuid, 16);
485 memcpy(u1[i].label, u0[i].label, 32);
486
487 u1[i].first_reg = u0[i].first_reg;
488 u1[i].last_reg = u0[i].last_reg;
489 u1[i].invalidated = u0[i].invalidated;
490
491 u1[i].flags = 0;
492 u1[i].sectors = 0;
493 }
494 }
495
496 return NULL;
497}
498
499static int __uuid_write(struct cache_set *c)
500{
501 BKEY_PADDED(key) k;
502 struct closure cl;
503 struct cache *ca = c->cache;
504 unsigned int size;
505
506 closure_init_stack(&cl);
507 lockdep_assert_held(&bch_register_lock);
508
509 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
510 return 1;
511
512 size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS;
513 SET_KEY_SIZE(&k.key, size);
514 uuid_io(c, REQ_OP_WRITE, &k.key, &cl);
515 closure_sync(&cl);
516
517 /* Only one bucket used for uuid write */
518 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
519
520 bkey_copy(&c->uuid_bucket, &k.key);
521 bkey_put(c, &k.key);
522 return 0;
523}
524
525int bch_uuid_write(struct cache_set *c)
526{
527 int ret = __uuid_write(c);
528
529 if (!ret)
530 bch_journal_meta(c, NULL);
531
532 return ret;
533}
534
535static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
536{
537 struct uuid_entry *u;
538
539 for (u = c->uuids;
540 u < c->uuids + c->nr_uuids; u++)
541 if (!memcmp(u->uuid, uuid, 16))
542 return u;
543
544 return NULL;
545}
546
547static struct uuid_entry *uuid_find_empty(struct cache_set *c)
548{
549 static const char zero_uuid[16] = "\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_simple_remove(&bcache_device_idx,
885 first_minor_to_idx(disk->first_minor));
886 put_disk(disk);
887 }
888
889 bioset_exit(&d->bio_split);
890 kvfree(d->full_dirty_stripes);
891 kvfree(d->stripe_sectors_dirty);
892
893 closure_debug_destroy(&d->cl);
894}
895
896static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
897 sector_t sectors, struct block_device *cached_bdev,
898 const struct block_device_operations *ops)
899{
900 struct request_queue *q;
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 };
913 uint64_t n;
914 int idx;
915
916 if (cached_bdev) {
917 d->stripe_size = bdev_io_opt(cached_bdev) >> SECTOR_SHIFT;
918 lim.io_opt = umax(block_size, bdev_io_opt(cached_bdev));
919 }
920 if (!d->stripe_size)
921 d->stripe_size = 1 << 31;
922 else if (d->stripe_size < BCH_MIN_STRIPE_SZ)
923 d->stripe_size = roundup(BCH_MIN_STRIPE_SZ, d->stripe_size);
924
925 n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
926 if (!n || n > max_stripes) {
927 pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
928 n);
929 return -ENOMEM;
930 }
931 d->nr_stripes = n;
932
933 n = d->nr_stripes * sizeof(atomic_t);
934 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
935 if (!d->stripe_sectors_dirty)
936 return -ENOMEM;
937
938 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
939 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
940 if (!d->full_dirty_stripes)
941 goto out_free_stripe_sectors_dirty;
942
943 idx = ida_simple_get(&bcache_device_idx, 0,
944 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
945 if (idx < 0)
946 goto out_free_full_dirty_stripes;
947
948 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
949 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
950 goto out_ida_remove;
951
952 if (lim.logical_block_size > PAGE_SIZE && cached_bdev) {
953 /*
954 * This should only happen with BCACHE_SB_VERSION_BDEV.
955 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
956 */
957 pr_info("bcache%i: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
958 idx, lim.logical_block_size,
959 PAGE_SIZE, bdev_logical_block_size(cached_bdev));
960
961 /* This also adjusts physical block size/min io size if needed */
962 lim.logical_block_size = bdev_logical_block_size(cached_bdev);
963 }
964
965 d->disk = blk_alloc_disk(&lim, NUMA_NO_NODE);
966 if (IS_ERR(d->disk))
967 goto out_bioset_exit;
968
969 set_capacity(d->disk, sectors);
970 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
971
972 d->disk->major = bcache_major;
973 d->disk->first_minor = idx_to_first_minor(idx);
974 d->disk->minors = BCACHE_MINORS;
975 d->disk->fops = ops;
976 d->disk->private_data = d;
977
978 q = d->disk->queue;
979
980 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
981
982 blk_queue_write_cache(q, true, true);
983
984 return 0;
985
986out_bioset_exit:
987 bioset_exit(&d->bio_split);
988out_ida_remove:
989 ida_simple_remove(&bcache_device_idx, idx);
990out_free_full_dirty_stripes:
991 kvfree(d->full_dirty_stripes);
992out_free_stripe_sectors_dirty:
993 kvfree(d->stripe_sectors_dirty);
994 return -ENOMEM;
995
996}
997
998/* Cached device */
999
1000static void calc_cached_dev_sectors(struct cache_set *c)
1001{
1002 uint64_t sectors = 0;
1003 struct cached_dev *dc;
1004
1005 list_for_each_entry(dc, &c->cached_devs, list)
1006 sectors += bdev_nr_sectors(dc->bdev);
1007
1008 c->cached_dev_sectors = sectors;
1009}
1010
1011#define BACKING_DEV_OFFLINE_TIMEOUT 5
1012static int cached_dev_status_update(void *arg)
1013{
1014 struct cached_dev *dc = arg;
1015 struct request_queue *q;
1016
1017 /*
1018 * If this delayed worker is stopping outside, directly quit here.
1019 * dc->io_disable might be set via sysfs interface, so check it
1020 * here too.
1021 */
1022 while (!kthread_should_stop() && !dc->io_disable) {
1023 q = bdev_get_queue(dc->bdev);
1024 if (blk_queue_dying(q))
1025 dc->offline_seconds++;
1026 else
1027 dc->offline_seconds = 0;
1028
1029 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1030 pr_err("%pg: device offline for %d seconds\n",
1031 dc->bdev,
1032 BACKING_DEV_OFFLINE_TIMEOUT);
1033 pr_err("%s: disable I/O request due to backing device offline\n",
1034 dc->disk.name);
1035 dc->io_disable = true;
1036 /* let others know earlier that io_disable is true */
1037 smp_mb();
1038 bcache_device_stop(&dc->disk);
1039 break;
1040 }
1041 schedule_timeout_interruptible(HZ);
1042 }
1043
1044 wait_for_kthread_stop();
1045 return 0;
1046}
1047
1048
1049int bch_cached_dev_run(struct cached_dev *dc)
1050{
1051 int ret = 0;
1052 struct bcache_device *d = &dc->disk;
1053 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1054 char *env[] = {
1055 "DRIVER=bcache",
1056 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1057 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1058 NULL,
1059 };
1060
1061 if (dc->io_disable) {
1062 pr_err("I/O disabled on cached dev %pg\n", dc->bdev);
1063 ret = -EIO;
1064 goto out;
1065 }
1066
1067 if (atomic_xchg(&dc->running, 1)) {
1068 pr_info("cached dev %pg is running already\n", dc->bdev);
1069 ret = -EBUSY;
1070 goto out;
1071 }
1072
1073 if (!d->c &&
1074 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1075 struct closure cl;
1076
1077 closure_init_stack(&cl);
1078
1079 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1080 bch_write_bdev_super(dc, &cl);
1081 closure_sync(&cl);
1082 }
1083
1084 ret = add_disk(d->disk);
1085 if (ret)
1086 goto out;
1087 bd_link_disk_holder(dc->bdev, dc->disk.disk);
1088 /*
1089 * won't show up in the uevent file, use udevadm monitor -e instead
1090 * only class / kset properties are persistent
1091 */
1092 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1093
1094 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1095 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1096 &d->kobj, "bcache")) {
1097 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1098 ret = -ENOMEM;
1099 goto out;
1100 }
1101
1102 dc->status_update_thread = kthread_run(cached_dev_status_update,
1103 dc, "bcache_status_update");
1104 if (IS_ERR(dc->status_update_thread)) {
1105 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1106 }
1107
1108out:
1109 kfree(env[1]);
1110 kfree(env[2]);
1111 kfree(buf);
1112 return ret;
1113}
1114
1115/*
1116 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1117 * work dc->writeback_rate_update is running. Wait until the routine
1118 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1119 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1120 * seconds, give up waiting here and continue to cancel it too.
1121 */
1122static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1123{
1124 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1125
1126 do {
1127 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1128 &dc->disk.flags))
1129 break;
1130 time_out--;
1131 schedule_timeout_interruptible(1);
1132 } while (time_out > 0);
1133
1134 if (time_out == 0)
1135 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1136
1137 cancel_delayed_work_sync(&dc->writeback_rate_update);
1138}
1139
1140static void cached_dev_detach_finish(struct work_struct *w)
1141{
1142 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1143 struct cache_set *c = dc->disk.c;
1144
1145 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1146 BUG_ON(refcount_read(&dc->count));
1147
1148
1149 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1150 cancel_writeback_rate_update_dwork(dc);
1151
1152 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1153 kthread_stop(dc->writeback_thread);
1154 dc->writeback_thread = NULL;
1155 }
1156
1157 mutex_lock(&bch_register_lock);
1158
1159 bcache_device_detach(&dc->disk);
1160 list_move(&dc->list, &uncached_devices);
1161 calc_cached_dev_sectors(c);
1162
1163 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1164 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1165
1166 mutex_unlock(&bch_register_lock);
1167
1168 pr_info("Caching disabled for %pg\n", dc->bdev);
1169
1170 /* Drop ref we took in cached_dev_detach() */
1171 closure_put(&dc->disk.cl);
1172}
1173
1174void bch_cached_dev_detach(struct cached_dev *dc)
1175{
1176 lockdep_assert_held(&bch_register_lock);
1177
1178 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1179 return;
1180
1181 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1182 return;
1183
1184 /*
1185 * Block the device from being closed and freed until we're finished
1186 * detaching
1187 */
1188 closure_get(&dc->disk.cl);
1189
1190 bch_writeback_queue(dc);
1191
1192 cached_dev_put(dc);
1193}
1194
1195int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1196 uint8_t *set_uuid)
1197{
1198 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1199 struct uuid_entry *u;
1200 struct cached_dev *exist_dc, *t;
1201 int ret = 0;
1202
1203 if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
1204 (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
1205 return -ENOENT;
1206
1207 if (dc->disk.c) {
1208 pr_err("Can't attach %pg: already attached\n", dc->bdev);
1209 return -EINVAL;
1210 }
1211
1212 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1213 pr_err("Can't attach %pg: shutting down\n", dc->bdev);
1214 return -EINVAL;
1215 }
1216
1217 if (dc->sb.block_size < c->cache->sb.block_size) {
1218 /* Will die */
1219 pr_err("Couldn't attach %pg: block size less than set's block size\n",
1220 dc->bdev);
1221 return -EINVAL;
1222 }
1223
1224 /* Check whether already attached */
1225 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1226 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1227 pr_err("Tried to attach %pg but duplicate UUID already attached\n",
1228 dc->bdev);
1229
1230 return -EINVAL;
1231 }
1232 }
1233
1234 u = uuid_find(c, dc->sb.uuid);
1235
1236 if (u &&
1237 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1238 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1239 memcpy(u->uuid, invalid_uuid, 16);
1240 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1241 u = NULL;
1242 }
1243
1244 if (!u) {
1245 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1246 pr_err("Couldn't find uuid for %pg in set\n", dc->bdev);
1247 return -ENOENT;
1248 }
1249
1250 u = uuid_find_empty(c);
1251 if (!u) {
1252 pr_err("Not caching %pg, no room for UUID\n", dc->bdev);
1253 return -EINVAL;
1254 }
1255 }
1256
1257 /*
1258 * Deadlocks since we're called via sysfs...
1259 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1260 */
1261
1262 if (bch_is_zero(u->uuid, 16)) {
1263 struct closure cl;
1264
1265 closure_init_stack(&cl);
1266
1267 memcpy(u->uuid, dc->sb.uuid, 16);
1268 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1269 u->first_reg = u->last_reg = rtime;
1270 bch_uuid_write(c);
1271
1272 memcpy(dc->sb.set_uuid, c->set_uuid, 16);
1273 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1274
1275 bch_write_bdev_super(dc, &cl);
1276 closure_sync(&cl);
1277 } else {
1278 u->last_reg = rtime;
1279 bch_uuid_write(c);
1280 }
1281
1282 bcache_device_attach(&dc->disk, c, u - c->uuids);
1283 list_move(&dc->list, &c->cached_devs);
1284 calc_cached_dev_sectors(c);
1285
1286 /*
1287 * dc->c must be set before dc->count != 0 - paired with the mb in
1288 * cached_dev_get()
1289 */
1290 smp_wmb();
1291 refcount_set(&dc->count, 1);
1292
1293 /* Block writeback thread, but spawn it */
1294 down_write(&dc->writeback_lock);
1295 if (bch_cached_dev_writeback_start(dc)) {
1296 up_write(&dc->writeback_lock);
1297 pr_err("Couldn't start writeback facilities for %s\n",
1298 dc->disk.disk->disk_name);
1299 return -ENOMEM;
1300 }
1301
1302 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1303 atomic_set(&dc->has_dirty, 1);
1304 bch_writeback_queue(dc);
1305 }
1306
1307 bch_sectors_dirty_init(&dc->disk);
1308
1309 ret = bch_cached_dev_run(dc);
1310 if (ret && (ret != -EBUSY)) {
1311 up_write(&dc->writeback_lock);
1312 /*
1313 * bch_register_lock is held, bcache_device_stop() is not
1314 * able to be directly called. The kthread and kworker
1315 * created previously in bch_cached_dev_writeback_start()
1316 * have to be stopped manually here.
1317 */
1318 kthread_stop(dc->writeback_thread);
1319 cancel_writeback_rate_update_dwork(dc);
1320 pr_err("Couldn't run cached device %pg\n", dc->bdev);
1321 return ret;
1322 }
1323
1324 bcache_device_link(&dc->disk, c, "bdev");
1325 atomic_inc(&c->attached_dev_nr);
1326
1327 if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
1328 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1329 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1330 set_disk_ro(dc->disk.disk, 1);
1331 }
1332
1333 /* Allow the writeback thread to proceed */
1334 up_write(&dc->writeback_lock);
1335
1336 pr_info("Caching %pg as %s on set %pU\n",
1337 dc->bdev,
1338 dc->disk.disk->disk_name,
1339 dc->disk.c->set_uuid);
1340 return 0;
1341}
1342
1343/* when dc->disk.kobj released */
1344void bch_cached_dev_release(struct kobject *kobj)
1345{
1346 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1347 disk.kobj);
1348 kfree(dc);
1349 module_put(THIS_MODULE);
1350}
1351
1352static CLOSURE_CALLBACK(cached_dev_free)
1353{
1354 closure_type(dc, struct cached_dev, disk.cl);
1355
1356 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1357 cancel_writeback_rate_update_dwork(dc);
1358
1359 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1360 kthread_stop(dc->writeback_thread);
1361 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1362 kthread_stop(dc->status_update_thread);
1363
1364 mutex_lock(&bch_register_lock);
1365
1366 if (atomic_read(&dc->running)) {
1367 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1368 del_gendisk(dc->disk.disk);
1369 }
1370 bcache_device_free(&dc->disk);
1371 list_del(&dc->list);
1372
1373 mutex_unlock(&bch_register_lock);
1374
1375 if (dc->sb_disk)
1376 put_page(virt_to_page(dc->sb_disk));
1377
1378 if (dc->bdev_file)
1379 fput(dc->bdev_file);
1380
1381 wake_up(&unregister_wait);
1382
1383 kobject_put(&dc->disk.kobj);
1384}
1385
1386static CLOSURE_CALLBACK(cached_dev_flush)
1387{
1388 closure_type(dc, struct cached_dev, disk.cl);
1389 struct bcache_device *d = &dc->disk;
1390
1391 mutex_lock(&bch_register_lock);
1392 bcache_device_unlink(d);
1393 mutex_unlock(&bch_register_lock);
1394
1395 bch_cache_accounting_destroy(&dc->accounting);
1396 kobject_del(&d->kobj);
1397
1398 continue_at(cl, cached_dev_free, system_wq);
1399}
1400
1401static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1402{
1403 int ret;
1404 struct io *io;
1405 struct request_queue *q = bdev_get_queue(dc->bdev);
1406
1407 __module_get(THIS_MODULE);
1408 INIT_LIST_HEAD(&dc->list);
1409 closure_init(&dc->disk.cl, NULL);
1410 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1411 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1412 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1413 sema_init(&dc->sb_write_mutex, 1);
1414 INIT_LIST_HEAD(&dc->io_lru);
1415 spin_lock_init(&dc->io_lock);
1416 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1417
1418 dc->sequential_cutoff = 4 << 20;
1419
1420 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1421 list_add(&io->lru, &dc->io_lru);
1422 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1423 }
1424
1425 if (bdev_io_opt(dc->bdev))
1426 dc->partial_stripes_expensive =
1427 q->limits.raid_partial_stripes_expensive;
1428
1429 ret = bcache_device_init(&dc->disk, block_size,
1430 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
1431 dc->bdev, &bcache_cached_ops);
1432 if (ret)
1433 return ret;
1434
1435 atomic_set(&dc->io_errors, 0);
1436 dc->io_disable = false;
1437 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1438 /* default to auto */
1439 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1440
1441 bch_cached_dev_request_init(dc);
1442 bch_cached_dev_writeback_init(dc);
1443 return 0;
1444}
1445
1446/* Cached device - bcache superblock */
1447
1448static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1449 struct file *bdev_file,
1450 struct cached_dev *dc)
1451{
1452 const char *err = "cannot allocate memory";
1453 struct cache_set *c;
1454 int ret = -ENOMEM;
1455
1456 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1457 dc->bdev_file = bdev_file;
1458 dc->bdev = file_bdev(bdev_file);
1459 dc->sb_disk = sb_disk;
1460
1461 if (cached_dev_init(dc, sb->block_size << 9))
1462 goto err;
1463
1464 err = "error creating kobject";
1465 if (kobject_add(&dc->disk.kobj, bdev_kobj(dc->bdev), "bcache"))
1466 goto err;
1467 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1468 goto err;
1469
1470 pr_info("registered backing device %pg\n", dc->bdev);
1471
1472 list_add(&dc->list, &uncached_devices);
1473 /* attach to a matched cache set if it exists */
1474 list_for_each_entry(c, &bch_cache_sets, list)
1475 bch_cached_dev_attach(dc, c, NULL);
1476
1477 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1478 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1479 err = "failed to run cached device";
1480 ret = bch_cached_dev_run(dc);
1481 if (ret)
1482 goto err;
1483 }
1484
1485 return 0;
1486err:
1487 pr_notice("error %pg: %s\n", dc->bdev, err);
1488 bcache_device_stop(&dc->disk);
1489 return ret;
1490}
1491
1492/* Flash only volumes */
1493
1494/* When d->kobj released */
1495void bch_flash_dev_release(struct kobject *kobj)
1496{
1497 struct bcache_device *d = container_of(kobj, struct bcache_device,
1498 kobj);
1499 kfree(d);
1500}
1501
1502static CLOSURE_CALLBACK(flash_dev_free)
1503{
1504 closure_type(d, struct bcache_device, cl);
1505
1506 mutex_lock(&bch_register_lock);
1507 atomic_long_sub(bcache_dev_sectors_dirty(d),
1508 &d->c->flash_dev_dirty_sectors);
1509 del_gendisk(d->disk);
1510 bcache_device_free(d);
1511 mutex_unlock(&bch_register_lock);
1512 kobject_put(&d->kobj);
1513}
1514
1515static CLOSURE_CALLBACK(flash_dev_flush)
1516{
1517 closure_type(d, struct bcache_device, cl);
1518
1519 mutex_lock(&bch_register_lock);
1520 bcache_device_unlink(d);
1521 mutex_unlock(&bch_register_lock);
1522 kobject_del(&d->kobj);
1523 continue_at(cl, flash_dev_free, system_wq);
1524}
1525
1526static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1527{
1528 int err = -ENOMEM;
1529 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1530 GFP_KERNEL);
1531 if (!d)
1532 goto err_ret;
1533
1534 closure_init(&d->cl, NULL);
1535 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1536
1537 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1538
1539 if (bcache_device_init(d, block_bytes(c->cache), u->sectors,
1540 NULL, &bcache_flash_ops))
1541 goto err;
1542
1543 bcache_device_attach(d, c, u - c->uuids);
1544 bch_sectors_dirty_init(d);
1545 bch_flash_dev_request_init(d);
1546 err = add_disk(d->disk);
1547 if (err)
1548 goto err;
1549
1550 err = kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache");
1551 if (err)
1552 goto err;
1553
1554 bcache_device_link(d, c, "volume");
1555
1556 if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
1557 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1558 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1559 set_disk_ro(d->disk, 1);
1560 }
1561
1562 return 0;
1563err:
1564 kobject_put(&d->kobj);
1565err_ret:
1566 return err;
1567}
1568
1569static int flash_devs_run(struct cache_set *c)
1570{
1571 int ret = 0;
1572 struct uuid_entry *u;
1573
1574 for (u = c->uuids;
1575 u < c->uuids + c->nr_uuids && !ret;
1576 u++)
1577 if (UUID_FLASH_ONLY(u))
1578 ret = flash_dev_run(c, u);
1579
1580 return ret;
1581}
1582
1583int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1584{
1585 struct uuid_entry *u;
1586
1587 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1588 return -EINTR;
1589
1590 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1591 return -EPERM;
1592
1593 u = uuid_find_empty(c);
1594 if (!u) {
1595 pr_err("Can't create volume, no room for UUID\n");
1596 return -EINVAL;
1597 }
1598
1599 get_random_bytes(u->uuid, 16);
1600 memset(u->label, 0, 32);
1601 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1602
1603 SET_UUID_FLASH_ONLY(u, 1);
1604 u->sectors = size >> 9;
1605
1606 bch_uuid_write(c);
1607
1608 return flash_dev_run(c, u);
1609}
1610
1611bool bch_cached_dev_error(struct cached_dev *dc)
1612{
1613 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1614 return false;
1615
1616 dc->io_disable = true;
1617 /* make others know io_disable is true earlier */
1618 smp_mb();
1619
1620 pr_err("stop %s: too many IO errors on backing device %pg\n",
1621 dc->disk.disk->disk_name, dc->bdev);
1622
1623 bcache_device_stop(&dc->disk);
1624 return true;
1625}
1626
1627/* Cache set */
1628
1629__printf(2, 3)
1630bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1631{
1632 struct va_format vaf;
1633 va_list args;
1634
1635 if (c->on_error != ON_ERROR_PANIC &&
1636 test_bit(CACHE_SET_STOPPING, &c->flags))
1637 return false;
1638
1639 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1640 pr_info("CACHE_SET_IO_DISABLE already set\n");
1641
1642 /*
1643 * XXX: we can be called from atomic context
1644 * acquire_console_sem();
1645 */
1646
1647 va_start(args, fmt);
1648
1649 vaf.fmt = fmt;
1650 vaf.va = &args;
1651
1652 pr_err("error on %pU: %pV, disabling caching\n",
1653 c->set_uuid, &vaf);
1654
1655 va_end(args);
1656
1657 if (c->on_error == ON_ERROR_PANIC)
1658 panic("panic forced after error\n");
1659
1660 bch_cache_set_unregister(c);
1661 return true;
1662}
1663
1664/* When c->kobj released */
1665void bch_cache_set_release(struct kobject *kobj)
1666{
1667 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1668
1669 kfree(c);
1670 module_put(THIS_MODULE);
1671}
1672
1673static CLOSURE_CALLBACK(cache_set_free)
1674{
1675 closure_type(c, struct cache_set, cl);
1676 struct cache *ca;
1677
1678 debugfs_remove(c->debug);
1679
1680 bch_open_buckets_free(c);
1681 bch_btree_cache_free(c);
1682 bch_journal_free(c);
1683
1684 mutex_lock(&bch_register_lock);
1685 bch_bset_sort_state_free(&c->sort);
1686 free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
1687
1688 ca = c->cache;
1689 if (ca) {
1690 ca->set = NULL;
1691 c->cache = NULL;
1692 kobject_put(&ca->kobj);
1693 }
1694
1695
1696 if (c->moving_gc_wq)
1697 destroy_workqueue(c->moving_gc_wq);
1698 bioset_exit(&c->bio_split);
1699 mempool_exit(&c->fill_iter);
1700 mempool_exit(&c->bio_meta);
1701 mempool_exit(&c->search);
1702 kfree(c->devices);
1703
1704 list_del(&c->list);
1705 mutex_unlock(&bch_register_lock);
1706
1707 pr_info("Cache set %pU unregistered\n", c->set_uuid);
1708 wake_up(&unregister_wait);
1709
1710 closure_debug_destroy(&c->cl);
1711 kobject_put(&c->kobj);
1712}
1713
1714static CLOSURE_CALLBACK(cache_set_flush)
1715{
1716 closure_type(c, struct cache_set, caching);
1717 struct cache *ca = c->cache;
1718 struct btree *b;
1719
1720 bch_cache_accounting_destroy(&c->accounting);
1721
1722 kobject_put(&c->internal);
1723 kobject_del(&c->kobj);
1724
1725 if (!IS_ERR_OR_NULL(c->gc_thread))
1726 kthread_stop(c->gc_thread);
1727
1728 if (!IS_ERR(c->root))
1729 list_add(&c->root->list, &c->btree_cache);
1730
1731 /*
1732 * Avoid flushing cached nodes if cache set is retiring
1733 * due to too many I/O errors detected.
1734 */
1735 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1736 list_for_each_entry(b, &c->btree_cache, list) {
1737 mutex_lock(&b->write_lock);
1738 if (btree_node_dirty(b))
1739 __bch_btree_node_write(b, NULL);
1740 mutex_unlock(&b->write_lock);
1741 }
1742
1743 if (ca->alloc_thread)
1744 kthread_stop(ca->alloc_thread);
1745
1746 if (c->journal.cur) {
1747 cancel_delayed_work_sync(&c->journal.work);
1748 /* flush last journal entry if needed */
1749 c->journal.work.work.func(&c->journal.work.work);
1750 }
1751
1752 closure_return(cl);
1753}
1754
1755/*
1756 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1757 * cache set is unregistering due to too many I/O errors. In this condition,
1758 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1759 * value and whether the broken cache has dirty data:
1760 *
1761 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1762 * BCH_CACHED_STOP_AUTO 0 NO
1763 * BCH_CACHED_STOP_AUTO 1 YES
1764 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1765 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1766 *
1767 * The expected behavior is, if stop_when_cache_set_failed is configured to
1768 * "auto" via sysfs interface, the bcache device will not be stopped if the
1769 * backing device is clean on the broken cache device.
1770 */
1771static void conditional_stop_bcache_device(struct cache_set *c,
1772 struct bcache_device *d,
1773 struct cached_dev *dc)
1774{
1775 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1776 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1777 d->disk->disk_name, c->set_uuid);
1778 bcache_device_stop(d);
1779 } else if (atomic_read(&dc->has_dirty)) {
1780 /*
1781 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1782 * and dc->has_dirty == 1
1783 */
1784 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1785 d->disk->disk_name);
1786 /*
1787 * There might be a small time gap that cache set is
1788 * released but bcache device is not. Inside this time
1789 * gap, regular I/O requests will directly go into
1790 * backing device as no cache set attached to. This
1791 * behavior may also introduce potential inconsistence
1792 * data in writeback mode while cache is dirty.
1793 * Therefore before calling bcache_device_stop() due
1794 * to a broken cache device, dc->io_disable should be
1795 * explicitly set to true.
1796 */
1797 dc->io_disable = true;
1798 /* make others know io_disable is true earlier */
1799 smp_mb();
1800 bcache_device_stop(d);
1801 } else {
1802 /*
1803 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1804 * and dc->has_dirty == 0
1805 */
1806 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1807 d->disk->disk_name);
1808 }
1809}
1810
1811static CLOSURE_CALLBACK(__cache_set_unregister)
1812{
1813 closure_type(c, struct cache_set, caching);
1814 struct cached_dev *dc;
1815 struct bcache_device *d;
1816 size_t i;
1817
1818 mutex_lock(&bch_register_lock);
1819
1820 for (i = 0; i < c->devices_max_used; i++) {
1821 d = c->devices[i];
1822 if (!d)
1823 continue;
1824
1825 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1826 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1827 dc = container_of(d, struct cached_dev, disk);
1828 bch_cached_dev_detach(dc);
1829 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1830 conditional_stop_bcache_device(c, d, dc);
1831 } else {
1832 bcache_device_stop(d);
1833 }
1834 }
1835
1836 mutex_unlock(&bch_register_lock);
1837
1838 continue_at(cl, cache_set_flush, system_wq);
1839}
1840
1841void bch_cache_set_stop(struct cache_set *c)
1842{
1843 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1844 /* closure_fn set to __cache_set_unregister() */
1845 closure_queue(&c->caching);
1846}
1847
1848void bch_cache_set_unregister(struct cache_set *c)
1849{
1850 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1851 bch_cache_set_stop(c);
1852}
1853
1854#define alloc_meta_bucket_pages(gfp, sb) \
1855 ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1856
1857struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1858{
1859 int iter_size;
1860 struct cache *ca = container_of(sb, struct cache, sb);
1861 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1862
1863 if (!c)
1864 return NULL;
1865
1866 __module_get(THIS_MODULE);
1867 closure_init(&c->cl, NULL);
1868 set_closure_fn(&c->cl, cache_set_free, system_wq);
1869
1870 closure_init(&c->caching, &c->cl);
1871 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1872
1873 /* Maybe create continue_at_noreturn() and use it here? */
1874 closure_set_stopped(&c->cl);
1875 closure_put(&c->cl);
1876
1877 kobject_init(&c->kobj, &bch_cache_set_ktype);
1878 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1879
1880 bch_cache_accounting_init(&c->accounting, &c->cl);
1881
1882 memcpy(c->set_uuid, sb->set_uuid, 16);
1883
1884 c->cache = ca;
1885 c->cache->set = c;
1886 c->bucket_bits = ilog2(sb->bucket_size);
1887 c->block_bits = ilog2(sb->block_size);
1888 c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
1889 c->devices_max_used = 0;
1890 atomic_set(&c->attached_dev_nr, 0);
1891 c->btree_pages = meta_bucket_pages(sb);
1892 if (c->btree_pages > BTREE_MAX_PAGES)
1893 c->btree_pages = max_t(int, c->btree_pages / 4,
1894 BTREE_MAX_PAGES);
1895
1896 sema_init(&c->sb_write_mutex, 1);
1897 mutex_init(&c->bucket_lock);
1898 init_waitqueue_head(&c->btree_cache_wait);
1899 spin_lock_init(&c->btree_cannibalize_lock);
1900 init_waitqueue_head(&c->bucket_wait);
1901 init_waitqueue_head(&c->gc_wait);
1902 sema_init(&c->uuid_write_mutex, 1);
1903
1904 spin_lock_init(&c->btree_gc_time.lock);
1905 spin_lock_init(&c->btree_split_time.lock);
1906 spin_lock_init(&c->btree_read_time.lock);
1907
1908 bch_moving_init_cache_set(c);
1909
1910 INIT_LIST_HEAD(&c->list);
1911 INIT_LIST_HEAD(&c->cached_devs);
1912 INIT_LIST_HEAD(&c->btree_cache);
1913 INIT_LIST_HEAD(&c->btree_cache_freeable);
1914 INIT_LIST_HEAD(&c->btree_cache_freed);
1915 INIT_LIST_HEAD(&c->data_buckets);
1916
1917 iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
1918 sizeof(struct btree_iter_set);
1919
1920 c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1921 if (!c->devices)
1922 goto err;
1923
1924 if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1925 goto err;
1926
1927 if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1928 sizeof(struct bbio) +
1929 sizeof(struct bio_vec) * meta_bucket_pages(sb)))
1930 goto err;
1931
1932 if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1933 goto err;
1934
1935 if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1936 BIOSET_NEED_RESCUER))
1937 goto err;
1938
1939 c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
1940 if (!c->uuids)
1941 goto err;
1942
1943 c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
1944 if (!c->moving_gc_wq)
1945 goto err;
1946
1947 if (bch_journal_alloc(c))
1948 goto err;
1949
1950 if (bch_btree_cache_alloc(c))
1951 goto err;
1952
1953 if (bch_open_buckets_alloc(c))
1954 goto err;
1955
1956 if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1957 goto err;
1958
1959 c->congested_read_threshold_us = 2000;
1960 c->congested_write_threshold_us = 20000;
1961 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1962 c->idle_max_writeback_rate_enabled = 1;
1963 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1964
1965 return c;
1966err:
1967 bch_cache_set_unregister(c);
1968 return NULL;
1969}
1970
1971static int run_cache_set(struct cache_set *c)
1972{
1973 const char *err = "cannot allocate memory";
1974 struct cached_dev *dc, *t;
1975 struct cache *ca = c->cache;
1976 struct closure cl;
1977 LIST_HEAD(journal);
1978 struct journal_replay *l;
1979
1980 closure_init_stack(&cl);
1981
1982 c->nbuckets = ca->sb.nbuckets;
1983 set_gc_sectors(c);
1984
1985 if (CACHE_SYNC(&c->cache->sb)) {
1986 struct bkey *k;
1987 struct jset *j;
1988
1989 err = "cannot allocate memory for journal";
1990 if (bch_journal_read(c, &journal))
1991 goto err;
1992
1993 pr_debug("btree_journal_read() done\n");
1994
1995 err = "no journal entries found";
1996 if (list_empty(&journal))
1997 goto err;
1998
1999 j = &list_entry(journal.prev, struct journal_replay, list)->j;
2000
2001 err = "IO error reading priorities";
2002 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2003 goto err;
2004
2005 /*
2006 * If prio_read() fails it'll call cache_set_error and we'll
2007 * tear everything down right away, but if we perhaps checked
2008 * sooner we could avoid journal replay.
2009 */
2010
2011 k = &j->btree_root;
2012
2013 err = "bad btree root";
2014 if (__bch_btree_ptr_invalid(c, k))
2015 goto err;
2016
2017 err = "error reading btree root";
2018 c->root = bch_btree_node_get(c, NULL, k,
2019 j->btree_level,
2020 true, NULL);
2021 if (IS_ERR(c->root))
2022 goto err;
2023
2024 list_del_init(&c->root->list);
2025 rw_unlock(true, c->root);
2026
2027 err = uuid_read(c, j, &cl);
2028 if (err)
2029 goto err;
2030
2031 err = "error in recovery";
2032 if (bch_btree_check(c))
2033 goto err;
2034
2035 bch_journal_mark(c, &journal);
2036 bch_initial_gc_finish(c);
2037 pr_debug("btree_check() done\n");
2038
2039 /*
2040 * bcache_journal_next() can't happen sooner, or
2041 * btree_gc_finish() will give spurious errors about last_gc >
2042 * gc_gen - this is a hack but oh well.
2043 */
2044 bch_journal_next(&c->journal);
2045
2046 err = "error starting allocator thread";
2047 if (bch_cache_allocator_start(ca))
2048 goto err;
2049
2050 /*
2051 * First place it's safe to allocate: btree_check() and
2052 * btree_gc_finish() have to run before we have buckets to
2053 * allocate, and bch_bucket_alloc_set() might cause a journal
2054 * entry to be written so bcache_journal_next() has to be called
2055 * first.
2056 *
2057 * If the uuids were in the old format we have to rewrite them
2058 * before the next journal entry is written:
2059 */
2060 if (j->version < BCACHE_JSET_VERSION_UUID)
2061 __uuid_write(c);
2062
2063 err = "bcache: replay journal failed";
2064 if (bch_journal_replay(c, &journal))
2065 goto err;
2066 } else {
2067 unsigned int j;
2068
2069 pr_notice("invalidating existing data\n");
2070 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2071 2, SB_JOURNAL_BUCKETS);
2072
2073 for (j = 0; j < ca->sb.keys; j++)
2074 ca->sb.d[j] = ca->sb.first_bucket + j;
2075
2076 bch_initial_gc_finish(c);
2077
2078 err = "error starting allocator thread";
2079 if (bch_cache_allocator_start(ca))
2080 goto err;
2081
2082 mutex_lock(&c->bucket_lock);
2083 bch_prio_write(ca, true);
2084 mutex_unlock(&c->bucket_lock);
2085
2086 err = "cannot allocate new UUID bucket";
2087 if (__uuid_write(c))
2088 goto err;
2089
2090 err = "cannot allocate new btree root";
2091 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2092 if (IS_ERR(c->root))
2093 goto err;
2094
2095 mutex_lock(&c->root->write_lock);
2096 bkey_copy_key(&c->root->key, &MAX_KEY);
2097 bch_btree_node_write(c->root, &cl);
2098 mutex_unlock(&c->root->write_lock);
2099
2100 bch_btree_set_root(c->root);
2101 rw_unlock(true, c->root);
2102
2103 /*
2104 * We don't want to write the first journal entry until
2105 * everything is set up - fortunately journal entries won't be
2106 * written until the SET_CACHE_SYNC() here:
2107 */
2108 SET_CACHE_SYNC(&c->cache->sb, true);
2109
2110 bch_journal_next(&c->journal);
2111 bch_journal_meta(c, &cl);
2112 }
2113
2114 err = "error starting gc thread";
2115 if (bch_gc_thread_start(c))
2116 goto err;
2117
2118 closure_sync(&cl);
2119 c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
2120 bcache_write_super(c);
2121
2122 if (bch_has_feature_obso_large_bucket(&c->cache->sb))
2123 pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
2124
2125 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2126 bch_cached_dev_attach(dc, c, NULL);
2127
2128 flash_devs_run(c);
2129
2130 bch_journal_space_reserve(&c->journal);
2131 set_bit(CACHE_SET_RUNNING, &c->flags);
2132 return 0;
2133err:
2134 while (!list_empty(&journal)) {
2135 l = list_first_entry(&journal, struct journal_replay, list);
2136 list_del(&l->list);
2137 kfree(l);
2138 }
2139
2140 closure_sync(&cl);
2141
2142 bch_cache_set_error(c, "%s", err);
2143
2144 return -EIO;
2145}
2146
2147static const char *register_cache_set(struct cache *ca)
2148{
2149 char buf[12];
2150 const char *err = "cannot allocate memory";
2151 struct cache_set *c;
2152
2153 list_for_each_entry(c, &bch_cache_sets, list)
2154 if (!memcmp(c->set_uuid, ca->sb.set_uuid, 16)) {
2155 if (c->cache)
2156 return "duplicate cache set member";
2157
2158 goto found;
2159 }
2160
2161 c = bch_cache_set_alloc(&ca->sb);
2162 if (!c)
2163 return err;
2164
2165 err = "error creating kobject";
2166 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->set_uuid) ||
2167 kobject_add(&c->internal, &c->kobj, "internal"))
2168 goto err;
2169
2170 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2171 goto err;
2172
2173 bch_debug_init_cache_set(c);
2174
2175 list_add(&c->list, &bch_cache_sets);
2176found:
2177 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2178 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2179 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2180 goto err;
2181
2182 kobject_get(&ca->kobj);
2183 ca->set = c;
2184 ca->set->cache = ca;
2185
2186 err = "failed to run cache set";
2187 if (run_cache_set(c) < 0)
2188 goto err;
2189
2190 return NULL;
2191err:
2192 bch_cache_set_unregister(c);
2193 return err;
2194}
2195
2196/* Cache device */
2197
2198/* When ca->kobj released */
2199void bch_cache_release(struct kobject *kobj)
2200{
2201 struct cache *ca = container_of(kobj, struct cache, kobj);
2202 unsigned int i;
2203
2204 if (ca->set) {
2205 BUG_ON(ca->set->cache != ca);
2206 ca->set->cache = NULL;
2207 }
2208
2209 free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2210 kfree(ca->prio_buckets);
2211 vfree(ca->buckets);
2212
2213 free_heap(&ca->heap);
2214 free_fifo(&ca->free_inc);
2215
2216 for (i = 0; i < RESERVE_NR; i++)
2217 free_fifo(&ca->free[i]);
2218
2219 if (ca->sb_disk)
2220 put_page(virt_to_page(ca->sb_disk));
2221
2222 if (ca->bdev_file)
2223 fput(ca->bdev_file);
2224
2225 kfree(ca);
2226 module_put(THIS_MODULE);
2227}
2228
2229static int cache_alloc(struct cache *ca)
2230{
2231 size_t free;
2232 size_t btree_buckets;
2233 struct bucket *b;
2234 int ret = -ENOMEM;
2235 const char *err = NULL;
2236
2237 __module_get(THIS_MODULE);
2238 kobject_init(&ca->kobj, &bch_cache_ktype);
2239
2240 bio_init(&ca->journal.bio, NULL, ca->journal.bio.bi_inline_vecs, 8, 0);
2241
2242 /*
2243 * when ca->sb.njournal_buckets is not zero, journal exists,
2244 * and in bch_journal_replay(), tree node may split,
2245 * so bucket of RESERVE_BTREE type is needed,
2246 * the worst situation is all journal buckets are valid journal,
2247 * and all the keys need to replay,
2248 * so the number of RESERVE_BTREE type buckets should be as much
2249 * as journal buckets
2250 */
2251 btree_buckets = ca->sb.njournal_buckets ?: 8;
2252 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2253 if (!free) {
2254 ret = -EPERM;
2255 err = "ca->sb.nbuckets is too small";
2256 goto err_free;
2257 }
2258
2259 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2260 GFP_KERNEL)) {
2261 err = "ca->free[RESERVE_BTREE] alloc failed";
2262 goto err_btree_alloc;
2263 }
2264
2265 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2266 GFP_KERNEL)) {
2267 err = "ca->free[RESERVE_PRIO] alloc failed";
2268 goto err_prio_alloc;
2269 }
2270
2271 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2272 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2273 goto err_movinggc_alloc;
2274 }
2275
2276 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2277 err = "ca->free[RESERVE_NONE] alloc failed";
2278 goto err_none_alloc;
2279 }
2280
2281 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2282 err = "ca->free_inc alloc failed";
2283 goto err_free_inc_alloc;
2284 }
2285
2286 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2287 err = "ca->heap alloc failed";
2288 goto err_heap_alloc;
2289 }
2290
2291 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2292 ca->sb.nbuckets));
2293 if (!ca->buckets) {
2294 err = "ca->buckets alloc failed";
2295 goto err_buckets_alloc;
2296 }
2297
2298 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2299 prio_buckets(ca), 2),
2300 GFP_KERNEL);
2301 if (!ca->prio_buckets) {
2302 err = "ca->prio_buckets alloc failed";
2303 goto err_prio_buckets_alloc;
2304 }
2305
2306 ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2307 if (!ca->disk_buckets) {
2308 err = "ca->disk_buckets alloc failed";
2309 goto err_disk_buckets_alloc;
2310 }
2311
2312 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2313
2314 for_each_bucket(b, ca)
2315 atomic_set(&b->pin, 0);
2316 return 0;
2317
2318err_disk_buckets_alloc:
2319 kfree(ca->prio_buckets);
2320err_prio_buckets_alloc:
2321 vfree(ca->buckets);
2322err_buckets_alloc:
2323 free_heap(&ca->heap);
2324err_heap_alloc:
2325 free_fifo(&ca->free_inc);
2326err_free_inc_alloc:
2327 free_fifo(&ca->free[RESERVE_NONE]);
2328err_none_alloc:
2329 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2330err_movinggc_alloc:
2331 free_fifo(&ca->free[RESERVE_PRIO]);
2332err_prio_alloc:
2333 free_fifo(&ca->free[RESERVE_BTREE]);
2334err_btree_alloc:
2335err_free:
2336 module_put(THIS_MODULE);
2337 if (err)
2338 pr_notice("error %pg: %s\n", ca->bdev, err);
2339 return ret;
2340}
2341
2342static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2343 struct file *bdev_file,
2344 struct cache *ca)
2345{
2346 const char *err = NULL; /* must be set for any error case */
2347 int ret = 0;
2348
2349 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2350 ca->bdev_file = bdev_file;
2351 ca->bdev = file_bdev(bdev_file);
2352 ca->sb_disk = sb_disk;
2353
2354 if (bdev_max_discard_sectors(file_bdev(bdev_file)))
2355 ca->discard = CACHE_DISCARD(&ca->sb);
2356
2357 ret = cache_alloc(ca);
2358 if (ret != 0) {
2359 if (ret == -ENOMEM)
2360 err = "cache_alloc(): -ENOMEM";
2361 else if (ret == -EPERM)
2362 err = "cache_alloc(): cache device is too small";
2363 else
2364 err = "cache_alloc(): unknown error";
2365 pr_notice("error %pg: %s\n", file_bdev(bdev_file), err);
2366 /*
2367 * If we failed here, it means ca->kobj is not initialized yet,
2368 * kobject_put() won't be called and there is no chance to
2369 * call fput() to bdev in bch_cache_release(). So
2370 * we explicitly call fput() on the block device here.
2371 */
2372 fput(bdev_file);
2373 return ret;
2374 }
2375
2376 if (kobject_add(&ca->kobj, bdev_kobj(file_bdev(bdev_file)), "bcache")) {
2377 pr_notice("error %pg: error calling kobject_add\n",
2378 file_bdev(bdev_file));
2379 ret = -ENOMEM;
2380 goto out;
2381 }
2382
2383 mutex_lock(&bch_register_lock);
2384 err = register_cache_set(ca);
2385 mutex_unlock(&bch_register_lock);
2386
2387 if (err) {
2388 ret = -ENODEV;
2389 goto out;
2390 }
2391
2392 pr_info("registered cache device %pg\n", file_bdev(ca->bdev_file));
2393
2394out:
2395 kobject_put(&ca->kobj);
2396 return ret;
2397}
2398
2399/* Global interfaces/init */
2400
2401static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2402 const char *buffer, size_t size);
2403static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2404 struct kobj_attribute *attr,
2405 const char *buffer, size_t size);
2406
2407kobj_attribute_write(register, register_bcache);
2408kobj_attribute_write(register_quiet, register_bcache);
2409kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2410
2411static bool bch_is_open_backing(dev_t dev)
2412{
2413 struct cache_set *c, *tc;
2414 struct cached_dev *dc, *t;
2415
2416 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2417 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2418 if (dc->bdev->bd_dev == dev)
2419 return true;
2420 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2421 if (dc->bdev->bd_dev == dev)
2422 return true;
2423 return false;
2424}
2425
2426static bool bch_is_open_cache(dev_t dev)
2427{
2428 struct cache_set *c, *tc;
2429
2430 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2431 struct cache *ca = c->cache;
2432
2433 if (ca->bdev->bd_dev == dev)
2434 return true;
2435 }
2436
2437 return false;
2438}
2439
2440static bool bch_is_open(dev_t dev)
2441{
2442 return bch_is_open_cache(dev) || bch_is_open_backing(dev);
2443}
2444
2445struct async_reg_args {
2446 struct delayed_work reg_work;
2447 char *path;
2448 struct cache_sb *sb;
2449 struct cache_sb_disk *sb_disk;
2450 struct file *bdev_file;
2451 void *holder;
2452};
2453
2454static void register_bdev_worker(struct work_struct *work)
2455{
2456 int fail = false;
2457 struct async_reg_args *args =
2458 container_of(work, struct async_reg_args, reg_work.work);
2459
2460 mutex_lock(&bch_register_lock);
2461 if (register_bdev(args->sb, args->sb_disk, args->bdev_file,
2462 args->holder) < 0)
2463 fail = true;
2464 mutex_unlock(&bch_register_lock);
2465
2466 if (fail)
2467 pr_info("error %s: fail to register backing device\n",
2468 args->path);
2469 kfree(args->sb);
2470 kfree(args->path);
2471 kfree(args);
2472 module_put(THIS_MODULE);
2473}
2474
2475static void register_cache_worker(struct work_struct *work)
2476{
2477 int fail = false;
2478 struct async_reg_args *args =
2479 container_of(work, struct async_reg_args, reg_work.work);
2480
2481 /* blkdev_put() will be called in bch_cache_release() */
2482 if (register_cache(args->sb, args->sb_disk, args->bdev_file,
2483 args->holder))
2484 fail = true;
2485
2486 if (fail)
2487 pr_info("error %s: fail to register cache device\n",
2488 args->path);
2489 kfree(args->sb);
2490 kfree(args->path);
2491 kfree(args);
2492 module_put(THIS_MODULE);
2493}
2494
2495static void register_device_async(struct async_reg_args *args)
2496{
2497 if (SB_IS_BDEV(args->sb))
2498 INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2499 else
2500 INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2501
2502 /* 10 jiffies is enough for a delay */
2503 queue_delayed_work(system_wq, &args->reg_work, 10);
2504}
2505
2506static void *alloc_holder_object(struct cache_sb *sb)
2507{
2508 if (SB_IS_BDEV(sb))
2509 return kzalloc(sizeof(struct cached_dev), GFP_KERNEL);
2510 return kzalloc(sizeof(struct cache), GFP_KERNEL);
2511}
2512
2513static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2514 const char *buffer, size_t size)
2515{
2516 const char *err;
2517 char *path = NULL;
2518 struct cache_sb *sb;
2519 struct cache_sb_disk *sb_disk;
2520 struct file *bdev_file, *bdev_file2;
2521 void *holder = NULL;
2522 ssize_t ret;
2523 bool async_registration = false;
2524 bool quiet = false;
2525
2526#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2527 async_registration = true;
2528#endif
2529
2530 ret = -EBUSY;
2531 err = "failed to reference bcache module";
2532 if (!try_module_get(THIS_MODULE))
2533 goto out;
2534
2535 /* For latest state of bcache_is_reboot */
2536 smp_mb();
2537 err = "bcache is in reboot";
2538 if (bcache_is_reboot)
2539 goto out_module_put;
2540
2541 ret = -ENOMEM;
2542 err = "cannot allocate memory";
2543 path = kstrndup(buffer, size, GFP_KERNEL);
2544 if (!path)
2545 goto out_module_put;
2546
2547 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2548 if (!sb)
2549 goto out_free_path;
2550
2551 ret = -EINVAL;
2552 err = "failed to open device";
2553 bdev_file = bdev_file_open_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
2554 if (IS_ERR(bdev_file))
2555 goto out_free_sb;
2556
2557 err = "failed to set blocksize";
2558 if (set_blocksize(file_bdev(bdev_file), 4096))
2559 goto out_blkdev_put;
2560
2561 err = read_super(sb, file_bdev(bdev_file), &sb_disk);
2562 if (err)
2563 goto out_blkdev_put;
2564
2565 holder = alloc_holder_object(sb);
2566 if (!holder) {
2567 ret = -ENOMEM;
2568 err = "cannot allocate memory";
2569 goto out_put_sb_page;
2570 }
2571
2572 /* Now reopen in exclusive mode with proper holder */
2573 bdev_file2 = bdev_file_open_by_dev(file_bdev(bdev_file)->bd_dev,
2574 BLK_OPEN_READ | BLK_OPEN_WRITE, holder, NULL);
2575 fput(bdev_file);
2576 bdev_file = bdev_file2;
2577 if (IS_ERR(bdev_file)) {
2578 ret = PTR_ERR(bdev_file);
2579 bdev_file = NULL;
2580 if (ret == -EBUSY) {
2581 dev_t dev;
2582
2583 mutex_lock(&bch_register_lock);
2584 if (lookup_bdev(strim(path), &dev) == 0 &&
2585 bch_is_open(dev))
2586 err = "device already registered";
2587 else
2588 err = "device busy";
2589 mutex_unlock(&bch_register_lock);
2590 if (attr == &ksysfs_register_quiet) {
2591 quiet = true;
2592 ret = size;
2593 }
2594 }
2595 goto out_free_holder;
2596 }
2597
2598 err = "failed to register device";
2599
2600 if (async_registration) {
2601 /* register in asynchronous way */
2602 struct async_reg_args *args =
2603 kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2604
2605 if (!args) {
2606 ret = -ENOMEM;
2607 err = "cannot allocate memory";
2608 goto out_free_holder;
2609 }
2610
2611 args->path = path;
2612 args->sb = sb;
2613 args->sb_disk = sb_disk;
2614 args->bdev_file = bdev_file;
2615 args->holder = holder;
2616 register_device_async(args);
2617 /* No wait and returns to user space */
2618 goto async_done;
2619 }
2620
2621 if (SB_IS_BDEV(sb)) {
2622 mutex_lock(&bch_register_lock);
2623 ret = register_bdev(sb, sb_disk, bdev_file, holder);
2624 mutex_unlock(&bch_register_lock);
2625 /* blkdev_put() will be called in cached_dev_free() */
2626 if (ret < 0)
2627 goto out_free_sb;
2628 } else {
2629 /* blkdev_put() will be called in bch_cache_release() */
2630 ret = register_cache(sb, sb_disk, bdev_file, holder);
2631 if (ret)
2632 goto out_free_sb;
2633 }
2634
2635 kfree(sb);
2636 kfree(path);
2637 module_put(THIS_MODULE);
2638async_done:
2639 return size;
2640
2641out_free_holder:
2642 kfree(holder);
2643out_put_sb_page:
2644 put_page(virt_to_page(sb_disk));
2645out_blkdev_put:
2646 if (bdev_file)
2647 fput(bdev_file);
2648out_free_sb:
2649 kfree(sb);
2650out_free_path:
2651 kfree(path);
2652 path = NULL;
2653out_module_put:
2654 module_put(THIS_MODULE);
2655out:
2656 if (!quiet)
2657 pr_info("error %s: %s\n", path?path:"", err);
2658 return ret;
2659}
2660
2661
2662struct pdev {
2663 struct list_head list;
2664 struct cached_dev *dc;
2665};
2666
2667static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2668 struct kobj_attribute *attr,
2669 const char *buffer,
2670 size_t size)
2671{
2672 LIST_HEAD(pending_devs);
2673 ssize_t ret = size;
2674 struct cached_dev *dc, *tdc;
2675 struct pdev *pdev, *tpdev;
2676 struct cache_set *c, *tc;
2677
2678 mutex_lock(&bch_register_lock);
2679 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2680 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2681 if (!pdev)
2682 break;
2683 pdev->dc = dc;
2684 list_add(&pdev->list, &pending_devs);
2685 }
2686
2687 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2688 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2689 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2690 char *set_uuid = c->set_uuid;
2691
2692 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2693 list_del(&pdev->list);
2694 kfree(pdev);
2695 break;
2696 }
2697 }
2698 }
2699 mutex_unlock(&bch_register_lock);
2700
2701 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2702 pr_info("delete pdev %p\n", pdev);
2703 list_del(&pdev->list);
2704 bcache_device_stop(&pdev->dc->disk);
2705 kfree(pdev);
2706 }
2707
2708 return ret;
2709}
2710
2711static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2712{
2713 if (bcache_is_reboot)
2714 return NOTIFY_DONE;
2715
2716 if (code == SYS_DOWN ||
2717 code == SYS_HALT ||
2718 code == SYS_POWER_OFF) {
2719 DEFINE_WAIT(wait);
2720 unsigned long start = jiffies;
2721 bool stopped = false;
2722
2723 struct cache_set *c, *tc;
2724 struct cached_dev *dc, *tdc;
2725
2726 mutex_lock(&bch_register_lock);
2727
2728 if (bcache_is_reboot)
2729 goto out;
2730
2731 /* New registration is rejected since now */
2732 bcache_is_reboot = true;
2733 /*
2734 * Make registering caller (if there is) on other CPU
2735 * core know bcache_is_reboot set to true earlier
2736 */
2737 smp_mb();
2738
2739 if (list_empty(&bch_cache_sets) &&
2740 list_empty(&uncached_devices))
2741 goto out;
2742
2743 mutex_unlock(&bch_register_lock);
2744
2745 pr_info("Stopping all devices:\n");
2746
2747 /*
2748 * The reason bch_register_lock is not held to call
2749 * bch_cache_set_stop() and bcache_device_stop() is to
2750 * avoid potential deadlock during reboot, because cache
2751 * set or bcache device stopping process will acquire
2752 * bch_register_lock too.
2753 *
2754 * We are safe here because bcache_is_reboot sets to
2755 * true already, register_bcache() will reject new
2756 * registration now. bcache_is_reboot also makes sure
2757 * bcache_reboot() won't be re-entered on by other thread,
2758 * so there is no race in following list iteration by
2759 * list_for_each_entry_safe().
2760 */
2761 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2762 bch_cache_set_stop(c);
2763
2764 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2765 bcache_device_stop(&dc->disk);
2766
2767
2768 /*
2769 * Give an early chance for other kthreads and
2770 * kworkers to stop themselves
2771 */
2772 schedule();
2773
2774 /* What's a condition variable? */
2775 while (1) {
2776 long timeout = start + 10 * HZ - jiffies;
2777
2778 mutex_lock(&bch_register_lock);
2779 stopped = list_empty(&bch_cache_sets) &&
2780 list_empty(&uncached_devices);
2781
2782 if (timeout < 0 || stopped)
2783 break;
2784
2785 prepare_to_wait(&unregister_wait, &wait,
2786 TASK_UNINTERRUPTIBLE);
2787
2788 mutex_unlock(&bch_register_lock);
2789 schedule_timeout(timeout);
2790 }
2791
2792 finish_wait(&unregister_wait, &wait);
2793
2794 if (stopped)
2795 pr_info("All devices stopped\n");
2796 else
2797 pr_notice("Timeout waiting for devices to be closed\n");
2798out:
2799 mutex_unlock(&bch_register_lock);
2800 }
2801
2802 return NOTIFY_DONE;
2803}
2804
2805static struct notifier_block reboot = {
2806 .notifier_call = bcache_reboot,
2807 .priority = INT_MAX, /* before any real devices */
2808};
2809
2810static void bcache_exit(void)
2811{
2812 bch_debug_exit();
2813 bch_request_exit();
2814 if (bcache_kobj)
2815 kobject_put(bcache_kobj);
2816 if (bcache_wq)
2817 destroy_workqueue(bcache_wq);
2818 if (bch_journal_wq)
2819 destroy_workqueue(bch_journal_wq);
2820 if (bch_flush_wq)
2821 destroy_workqueue(bch_flush_wq);
2822 bch_btree_exit();
2823
2824 if (bcache_major)
2825 unregister_blkdev(bcache_major, "bcache");
2826 unregister_reboot_notifier(&reboot);
2827 mutex_destroy(&bch_register_lock);
2828}
2829
2830/* Check and fixup module parameters */
2831static void check_module_parameters(void)
2832{
2833 if (bch_cutoff_writeback_sync == 0)
2834 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2835 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2836 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2837 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2838 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2839 }
2840
2841 if (bch_cutoff_writeback == 0)
2842 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2843 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2844 pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2845 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2846 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2847 }
2848
2849 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2850 pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2851 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2852 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2853 }
2854}
2855
2856static int __init bcache_init(void)
2857{
2858 static const struct attribute *files[] = {
2859 &ksysfs_register.attr,
2860 &ksysfs_register_quiet.attr,
2861 &ksysfs_pendings_cleanup.attr,
2862 NULL
2863 };
2864
2865 check_module_parameters();
2866
2867 mutex_init(&bch_register_lock);
2868 init_waitqueue_head(&unregister_wait);
2869 register_reboot_notifier(&reboot);
2870
2871 bcache_major = register_blkdev(0, "bcache");
2872 if (bcache_major < 0) {
2873 unregister_reboot_notifier(&reboot);
2874 mutex_destroy(&bch_register_lock);
2875 return bcache_major;
2876 }
2877
2878 if (bch_btree_init())
2879 goto err;
2880
2881 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2882 if (!bcache_wq)
2883 goto err;
2884
2885 /*
2886 * Let's not make this `WQ_MEM_RECLAIM` for the following reasons:
2887 *
2888 * 1. It used `system_wq` before which also does no memory reclaim.
2889 * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and
2890 * reduced throughput can be observed.
2891 *
2892 * We still want to user our own queue to not congest the `system_wq`.
2893 */
2894 bch_flush_wq = alloc_workqueue("bch_flush", 0, 0);
2895 if (!bch_flush_wq)
2896 goto err;
2897
2898 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2899 if (!bch_journal_wq)
2900 goto err;
2901
2902 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2903 if (!bcache_kobj)
2904 goto err;
2905
2906 if (bch_request_init() ||
2907 sysfs_create_files(bcache_kobj, files))
2908 goto err;
2909
2910 bch_debug_init();
2911
2912 bcache_is_reboot = false;
2913
2914 return 0;
2915err:
2916 bcache_exit();
2917 return -ENOMEM;
2918}
2919
2920/*
2921 * Module hooks
2922 */
2923module_exit(bcache_exit);
2924module_init(bcache_init);
2925
2926module_param(bch_cutoff_writeback, uint, 0);
2927MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2928
2929module_param(bch_cutoff_writeback_sync, uint, 0);
2930MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2931
2932MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2933MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2934MODULE_LICENSE("GPL");