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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/genhd.h>
22#include <linux/idr.h>
23#include <linux/kthread.h>
24#include <linux/workqueue.h>
25#include <linux/module.h>
26#include <linux/random.h>
27#include <linux/reboot.h>
28#include <linux/sysfs.h>
29
30unsigned int bch_cutoff_writeback;
31unsigned int bch_cutoff_writeback_sync;
32
33static const char bcache_magic[] = {
34 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
35 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
36};
37
38static const char invalid_uuid[] = {
39 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
40 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
41};
42
43static struct kobject *bcache_kobj;
44struct mutex bch_register_lock;
45bool bcache_is_reboot;
46LIST_HEAD(bch_cache_sets);
47static LIST_HEAD(uncached_devices);
48
49static int bcache_major;
50static DEFINE_IDA(bcache_device_idx);
51static wait_queue_head_t unregister_wait;
52struct workqueue_struct *bcache_wq;
53struct workqueue_struct *bch_flush_wq;
54struct workqueue_struct *bch_journal_wq;
55
56
57#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
58/* limitation of partitions number on single bcache device */
59#define BCACHE_MINORS 128
60/* limitation of bcache devices number on single system */
61#define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
62
63/* Superblock */
64
65static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s)
66{
67 unsigned int bucket_size = le16_to_cpu(s->bucket_size);
68
69 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
70 if (bch_has_feature_large_bucket(sb)) {
71 unsigned int max, order;
72
73 max = sizeof(unsigned int) * BITS_PER_BYTE - 1;
74 order = le16_to_cpu(s->bucket_size);
75 /*
76 * bcache tool will make sure the overflow won't
77 * happen, an error message here is enough.
78 */
79 if (order > max)
80 pr_err("Bucket size (1 << %u) overflows\n",
81 order);
82 bucket_size = 1 << order;
83 } else if (bch_has_feature_obso_large_bucket(sb)) {
84 bucket_size +=
85 le16_to_cpu(s->obso_bucket_size_hi) << 16;
86 }
87 }
88
89 return bucket_size;
90}
91
92static const char *read_super_common(struct cache_sb *sb, struct block_device *bdev,
93 struct cache_sb_disk *s)
94{
95 const char *err;
96 unsigned int i;
97
98 sb->first_bucket= le16_to_cpu(s->first_bucket);
99 sb->nbuckets = le64_to_cpu(s->nbuckets);
100 sb->bucket_size = get_bucket_size(sb, s);
101
102 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
103 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
104
105 err = "Too many journal buckets";
106 if (sb->keys > SB_JOURNAL_BUCKETS)
107 goto err;
108
109 err = "Too many buckets";
110 if (sb->nbuckets > LONG_MAX)
111 goto err;
112
113 err = "Not enough buckets";
114 if (sb->nbuckets < 1 << 7)
115 goto err;
116
117 err = "Bad block size (not power of 2)";
118 if (!is_power_of_2(sb->block_size))
119 goto err;
120
121 err = "Bad block size (larger than page size)";
122 if (sb->block_size > PAGE_SECTORS)
123 goto err;
124
125 err = "Bad bucket size (not power of 2)";
126 if (!is_power_of_2(sb->bucket_size))
127 goto err;
128
129 err = "Bad bucket size (smaller than page size)";
130 if (sb->bucket_size < PAGE_SECTORS)
131 goto err;
132
133 err = "Invalid superblock: device too small";
134 if (get_capacity(bdev->bd_disk) <
135 sb->bucket_size * sb->nbuckets)
136 goto err;
137
138 err = "Bad UUID";
139 if (bch_is_zero(sb->set_uuid, 16))
140 goto err;
141
142 err = "Bad cache device number in set";
143 if (!sb->nr_in_set ||
144 sb->nr_in_set <= sb->nr_this_dev ||
145 sb->nr_in_set > MAX_CACHES_PER_SET)
146 goto err;
147
148 err = "Journal buckets not sequential";
149 for (i = 0; i < sb->keys; i++)
150 if (sb->d[i] != sb->first_bucket + i)
151 goto err;
152
153 err = "Too many journal buckets";
154 if (sb->first_bucket + sb->keys > sb->nbuckets)
155 goto err;
156
157 err = "Invalid superblock: first bucket comes before end of super";
158 if (sb->first_bucket * sb->bucket_size < 16)
159 goto err;
160
161 err = NULL;
162err:
163 return err;
164}
165
166
167static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
168 struct cache_sb_disk **res)
169{
170 const char *err;
171 struct cache_sb_disk *s;
172 struct page *page;
173 unsigned int i;
174
175 page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
176 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
177 if (IS_ERR(page))
178 return "IO error";
179 s = page_address(page) + offset_in_page(SB_OFFSET);
180
181 sb->offset = le64_to_cpu(s->offset);
182 sb->version = le64_to_cpu(s->version);
183
184 memcpy(sb->magic, s->magic, 16);
185 memcpy(sb->uuid, s->uuid, 16);
186 memcpy(sb->set_uuid, s->set_uuid, 16);
187 memcpy(sb->label, s->label, SB_LABEL_SIZE);
188
189 sb->flags = le64_to_cpu(s->flags);
190 sb->seq = le64_to_cpu(s->seq);
191 sb->last_mount = le32_to_cpu(s->last_mount);
192 sb->keys = le16_to_cpu(s->keys);
193
194 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
195 sb->d[i] = le64_to_cpu(s->d[i]);
196
197 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u\n",
198 sb->version, sb->flags, sb->seq, sb->keys);
199
200 err = "Not a bcache superblock (bad offset)";
201 if (sb->offset != SB_SECTOR)
202 goto err;
203
204 err = "Not a bcache superblock (bad magic)";
205 if (memcmp(sb->magic, bcache_magic, 16))
206 goto err;
207
208 err = "Bad checksum";
209 if (s->csum != csum_set(s))
210 goto err;
211
212 err = "Bad UUID";
213 if (bch_is_zero(sb->uuid, 16))
214 goto err;
215
216 sb->block_size = le16_to_cpu(s->block_size);
217
218 err = "Superblock block size smaller than device block size";
219 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
220 goto err;
221
222 switch (sb->version) {
223 case BCACHE_SB_VERSION_BDEV:
224 sb->data_offset = BDEV_DATA_START_DEFAULT;
225 break;
226 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
227 case BCACHE_SB_VERSION_BDEV_WITH_FEATURES:
228 sb->data_offset = le64_to_cpu(s->data_offset);
229
230 err = "Bad data offset";
231 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
232 goto err;
233
234 break;
235 case BCACHE_SB_VERSION_CDEV:
236 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
237 err = read_super_common(sb, bdev, s);
238 if (err)
239 goto err;
240 break;
241 case BCACHE_SB_VERSION_CDEV_WITH_FEATURES:
242 /*
243 * Feature bits are needed in read_super_common(),
244 * convert them firstly.
245 */
246 sb->feature_compat = le64_to_cpu(s->feature_compat);
247 sb->feature_incompat = le64_to_cpu(s->feature_incompat);
248 sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat);
249
250 /* Check incompatible features */
251 err = "Unsupported compatible feature found";
252 if (bch_has_unknown_compat_features(sb))
253 goto err;
254
255 err = "Unsupported read-only compatible feature found";
256 if (bch_has_unknown_ro_compat_features(sb))
257 goto err;
258
259 err = "Unsupported incompatible feature found";
260 if (bch_has_unknown_incompat_features(sb))
261 goto err;
262
263 err = read_super_common(sb, bdev, s);
264 if (err)
265 goto err;
266 break;
267 default:
268 err = "Unsupported superblock version";
269 goto err;
270 }
271
272 sb->last_mount = (u32)ktime_get_real_seconds();
273 *res = s;
274 return NULL;
275err:
276 put_page(page);
277 return err;
278}
279
280static void write_bdev_super_endio(struct bio *bio)
281{
282 struct cached_dev *dc = bio->bi_private;
283
284 if (bio->bi_status)
285 bch_count_backing_io_errors(dc, bio);
286
287 closure_put(&dc->sb_write);
288}
289
290static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
291 struct bio *bio)
292{
293 unsigned int i;
294
295 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
296 bio->bi_iter.bi_sector = SB_SECTOR;
297 __bio_add_page(bio, virt_to_page(out), SB_SIZE,
298 offset_in_page(out));
299
300 out->offset = cpu_to_le64(sb->offset);
301
302 memcpy(out->uuid, sb->uuid, 16);
303 memcpy(out->set_uuid, sb->set_uuid, 16);
304 memcpy(out->label, sb->label, SB_LABEL_SIZE);
305
306 out->flags = cpu_to_le64(sb->flags);
307 out->seq = cpu_to_le64(sb->seq);
308
309 out->last_mount = cpu_to_le32(sb->last_mount);
310 out->first_bucket = cpu_to_le16(sb->first_bucket);
311 out->keys = cpu_to_le16(sb->keys);
312
313 for (i = 0; i < sb->keys; i++)
314 out->d[i] = cpu_to_le64(sb->d[i]);
315
316 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
317 out->feature_compat = cpu_to_le64(sb->feature_compat);
318 out->feature_incompat = cpu_to_le64(sb->feature_incompat);
319 out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
320 }
321
322 out->version = cpu_to_le64(sb->version);
323 out->csum = csum_set(out);
324
325 pr_debug("ver %llu, flags %llu, seq %llu\n",
326 sb->version, sb->flags, sb->seq);
327
328 submit_bio(bio);
329}
330
331static void bch_write_bdev_super_unlock(struct closure *cl)
332{
333 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
334
335 up(&dc->sb_write_mutex);
336}
337
338void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
339{
340 struct closure *cl = &dc->sb_write;
341 struct bio *bio = &dc->sb_bio;
342
343 down(&dc->sb_write_mutex);
344 closure_init(cl, parent);
345
346 bio_init(bio, dc->sb_bv, 1);
347 bio_set_dev(bio, dc->bdev);
348 bio->bi_end_io = write_bdev_super_endio;
349 bio->bi_private = dc;
350
351 closure_get(cl);
352 /* I/O request sent to backing device */
353 __write_super(&dc->sb, dc->sb_disk, bio);
354
355 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
356}
357
358static void write_super_endio(struct bio *bio)
359{
360 struct cache *ca = bio->bi_private;
361
362 /* is_read = 0 */
363 bch_count_io_errors(ca, bio->bi_status, 0,
364 "writing superblock");
365 closure_put(&ca->set->sb_write);
366}
367
368static void bcache_write_super_unlock(struct closure *cl)
369{
370 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
371
372 up(&c->sb_write_mutex);
373}
374
375void bcache_write_super(struct cache_set *c)
376{
377 struct closure *cl = &c->sb_write;
378 struct cache *ca = c->cache;
379 struct bio *bio = &ca->sb_bio;
380 unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
381
382 down(&c->sb_write_mutex);
383 closure_init(cl, &c->cl);
384
385 ca->sb.seq++;
386
387 if (ca->sb.version < version)
388 ca->sb.version = version;
389
390 bio_init(bio, ca->sb_bv, 1);
391 bio_set_dev(bio, ca->bdev);
392 bio->bi_end_io = write_super_endio;
393 bio->bi_private = ca;
394
395 closure_get(cl);
396 __write_super(&ca->sb, ca->sb_disk, bio);
397
398 closure_return_with_destructor(cl, bcache_write_super_unlock);
399}
400
401/* UUID io */
402
403static void uuid_endio(struct bio *bio)
404{
405 struct closure *cl = bio->bi_private;
406 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
407
408 cache_set_err_on(bio->bi_status, c, "accessing uuids");
409 bch_bbio_free(bio, c);
410 closure_put(cl);
411}
412
413static void uuid_io_unlock(struct closure *cl)
414{
415 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
416
417 up(&c->uuid_write_mutex);
418}
419
420static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
421 struct bkey *k, struct closure *parent)
422{
423 struct closure *cl = &c->uuid_write;
424 struct uuid_entry *u;
425 unsigned int i;
426 char buf[80];
427
428 BUG_ON(!parent);
429 down(&c->uuid_write_mutex);
430 closure_init(cl, parent);
431
432 for (i = 0; i < KEY_PTRS(k); i++) {
433 struct bio *bio = bch_bbio_alloc(c);
434
435 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
436 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
437
438 bio->bi_end_io = uuid_endio;
439 bio->bi_private = cl;
440 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
441 bch_bio_map(bio, c->uuids);
442
443 bch_submit_bbio(bio, c, k, i);
444
445 if (op != REQ_OP_WRITE)
446 break;
447 }
448
449 bch_extent_to_text(buf, sizeof(buf), k);
450 pr_debug("%s UUIDs at %s\n", op == REQ_OP_WRITE ? "wrote" : "read", buf);
451
452 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
453 if (!bch_is_zero(u->uuid, 16))
454 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
455 u - c->uuids, u->uuid, u->label,
456 u->first_reg, u->last_reg, u->invalidated);
457
458 closure_return_with_destructor(cl, uuid_io_unlock);
459}
460
461static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
462{
463 struct bkey *k = &j->uuid_bucket;
464
465 if (__bch_btree_ptr_invalid(c, k))
466 return "bad uuid pointer";
467
468 bkey_copy(&c->uuid_bucket, k);
469 uuid_io(c, REQ_OP_READ, 0, k, cl);
470
471 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
472 struct uuid_entry_v0 *u0 = (void *) c->uuids;
473 struct uuid_entry *u1 = (void *) c->uuids;
474 int i;
475
476 closure_sync(cl);
477
478 /*
479 * Since the new uuid entry is bigger than the old, we have to
480 * convert starting at the highest memory address and work down
481 * in order to do it in place
482 */
483
484 for (i = c->nr_uuids - 1;
485 i >= 0;
486 --i) {
487 memcpy(u1[i].uuid, u0[i].uuid, 16);
488 memcpy(u1[i].label, u0[i].label, 32);
489
490 u1[i].first_reg = u0[i].first_reg;
491 u1[i].last_reg = u0[i].last_reg;
492 u1[i].invalidated = u0[i].invalidated;
493
494 u1[i].flags = 0;
495 u1[i].sectors = 0;
496 }
497 }
498
499 return NULL;
500}
501
502static int __uuid_write(struct cache_set *c)
503{
504 BKEY_PADDED(key) k;
505 struct closure cl;
506 struct cache *ca = c->cache;
507 unsigned int size;
508
509 closure_init_stack(&cl);
510 lockdep_assert_held(&bch_register_lock);
511
512 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
513 return 1;
514
515 size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS;
516 SET_KEY_SIZE(&k.key, size);
517 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
518 closure_sync(&cl);
519
520 /* Only one bucket used for uuid write */
521 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
522
523 bkey_copy(&c->uuid_bucket, &k.key);
524 bkey_put(c, &k.key);
525 return 0;
526}
527
528int bch_uuid_write(struct cache_set *c)
529{
530 int ret = __uuid_write(c);
531
532 if (!ret)
533 bch_journal_meta(c, NULL);
534
535 return ret;
536}
537
538static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
539{
540 struct uuid_entry *u;
541
542 for (u = c->uuids;
543 u < c->uuids + c->nr_uuids; u++)
544 if (!memcmp(u->uuid, uuid, 16))
545 return u;
546
547 return NULL;
548}
549
550static struct uuid_entry *uuid_find_empty(struct cache_set *c)
551{
552 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
553
554 return uuid_find(c, zero_uuid);
555}
556
557/*
558 * Bucket priorities/gens:
559 *
560 * For each bucket, we store on disk its
561 * 8 bit gen
562 * 16 bit priority
563 *
564 * See alloc.c for an explanation of the gen. The priority is used to implement
565 * lru (and in the future other) cache replacement policies; for most purposes
566 * it's just an opaque integer.
567 *
568 * The gens and the priorities don't have a whole lot to do with each other, and
569 * it's actually the gens that must be written out at specific times - it's no
570 * big deal if the priorities don't get written, if we lose them we just reuse
571 * buckets in suboptimal order.
572 *
573 * On disk they're stored in a packed array, and in as many buckets are required
574 * to fit them all. The buckets we use to store them form a list; the journal
575 * header points to the first bucket, the first bucket points to the second
576 * bucket, et cetera.
577 *
578 * This code is used by the allocation code; periodically (whenever it runs out
579 * of buckets to allocate from) the allocation code will invalidate some
580 * buckets, but it can't use those buckets until their new gens are safely on
581 * disk.
582 */
583
584static void prio_endio(struct bio *bio)
585{
586 struct cache *ca = bio->bi_private;
587
588 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
589 bch_bbio_free(bio, ca->set);
590 closure_put(&ca->prio);
591}
592
593static void prio_io(struct cache *ca, uint64_t bucket, int op,
594 unsigned long op_flags)
595{
596 struct closure *cl = &ca->prio;
597 struct bio *bio = bch_bbio_alloc(ca->set);
598
599 closure_init_stack(cl);
600
601 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
602 bio_set_dev(bio, ca->bdev);
603 bio->bi_iter.bi_size = meta_bucket_bytes(&ca->sb);
604
605 bio->bi_end_io = prio_endio;
606 bio->bi_private = ca;
607 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
608 bch_bio_map(bio, ca->disk_buckets);
609
610 closure_bio_submit(ca->set, bio, &ca->prio);
611 closure_sync(cl);
612}
613
614int bch_prio_write(struct cache *ca, bool wait)
615{
616 int i;
617 struct bucket *b;
618 struct closure cl;
619
620 pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n",
621 fifo_used(&ca->free[RESERVE_PRIO]),
622 fifo_used(&ca->free[RESERVE_NONE]),
623 fifo_used(&ca->free_inc));
624
625 /*
626 * Pre-check if there are enough free buckets. In the non-blocking
627 * scenario it's better to fail early rather than starting to allocate
628 * buckets and do a cleanup later in case of failure.
629 */
630 if (!wait) {
631 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
632 fifo_used(&ca->free[RESERVE_NONE]);
633 if (prio_buckets(ca) > avail)
634 return -ENOMEM;
635 }
636
637 closure_init_stack(&cl);
638
639 lockdep_assert_held(&ca->set->bucket_lock);
640
641 ca->disk_buckets->seq++;
642
643 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
644 &ca->meta_sectors_written);
645
646 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
647 long bucket;
648 struct prio_set *p = ca->disk_buckets;
649 struct bucket_disk *d = p->data;
650 struct bucket_disk *end = d + prios_per_bucket(ca);
651
652 for (b = ca->buckets + i * prios_per_bucket(ca);
653 b < ca->buckets + ca->sb.nbuckets && d < end;
654 b++, d++) {
655 d->prio = cpu_to_le16(b->prio);
656 d->gen = b->gen;
657 }
658
659 p->next_bucket = ca->prio_buckets[i + 1];
660 p->magic = pset_magic(&ca->sb);
661 p->csum = bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8);
662
663 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
664 BUG_ON(bucket == -1);
665
666 mutex_unlock(&ca->set->bucket_lock);
667 prio_io(ca, bucket, REQ_OP_WRITE, 0);
668 mutex_lock(&ca->set->bucket_lock);
669
670 ca->prio_buckets[i] = bucket;
671 atomic_dec_bug(&ca->buckets[bucket].pin);
672 }
673
674 mutex_unlock(&ca->set->bucket_lock);
675
676 bch_journal_meta(ca->set, &cl);
677 closure_sync(&cl);
678
679 mutex_lock(&ca->set->bucket_lock);
680
681 /*
682 * Don't want the old priorities to get garbage collected until after we
683 * finish writing the new ones, and they're journalled
684 */
685 for (i = 0; i < prio_buckets(ca); i++) {
686 if (ca->prio_last_buckets[i])
687 __bch_bucket_free(ca,
688 &ca->buckets[ca->prio_last_buckets[i]]);
689
690 ca->prio_last_buckets[i] = ca->prio_buckets[i];
691 }
692 return 0;
693}
694
695static int prio_read(struct cache *ca, uint64_t bucket)
696{
697 struct prio_set *p = ca->disk_buckets;
698 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
699 struct bucket *b;
700 unsigned int bucket_nr = 0;
701 int ret = -EIO;
702
703 for (b = ca->buckets;
704 b < ca->buckets + ca->sb.nbuckets;
705 b++, d++) {
706 if (d == end) {
707 ca->prio_buckets[bucket_nr] = bucket;
708 ca->prio_last_buckets[bucket_nr] = bucket;
709 bucket_nr++;
710
711 prio_io(ca, bucket, REQ_OP_READ, 0);
712
713 if (p->csum !=
714 bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) {
715 pr_warn("bad csum reading priorities\n");
716 goto out;
717 }
718
719 if (p->magic != pset_magic(&ca->sb)) {
720 pr_warn("bad magic reading priorities\n");
721 goto out;
722 }
723
724 bucket = p->next_bucket;
725 d = p->data;
726 }
727
728 b->prio = le16_to_cpu(d->prio);
729 b->gen = b->last_gc = d->gen;
730 }
731
732 ret = 0;
733out:
734 return ret;
735}
736
737/* Bcache device */
738
739static int open_dev(struct block_device *b, fmode_t mode)
740{
741 struct bcache_device *d = b->bd_disk->private_data;
742
743 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
744 return -ENXIO;
745
746 closure_get(&d->cl);
747 return 0;
748}
749
750static void release_dev(struct gendisk *b, fmode_t mode)
751{
752 struct bcache_device *d = b->private_data;
753
754 closure_put(&d->cl);
755}
756
757static int ioctl_dev(struct block_device *b, fmode_t mode,
758 unsigned int cmd, unsigned long arg)
759{
760 struct bcache_device *d = b->bd_disk->private_data;
761
762 return d->ioctl(d, mode, cmd, arg);
763}
764
765static const struct block_device_operations bcache_cached_ops = {
766 .submit_bio = cached_dev_submit_bio,
767 .open = open_dev,
768 .release = release_dev,
769 .ioctl = ioctl_dev,
770 .owner = THIS_MODULE,
771};
772
773static const struct block_device_operations bcache_flash_ops = {
774 .submit_bio = flash_dev_submit_bio,
775 .open = open_dev,
776 .release = release_dev,
777 .ioctl = ioctl_dev,
778 .owner = THIS_MODULE,
779};
780
781void bcache_device_stop(struct bcache_device *d)
782{
783 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
784 /*
785 * closure_fn set to
786 * - cached device: cached_dev_flush()
787 * - flash dev: flash_dev_flush()
788 */
789 closure_queue(&d->cl);
790}
791
792static void bcache_device_unlink(struct bcache_device *d)
793{
794 lockdep_assert_held(&bch_register_lock);
795
796 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
797 struct cache *ca = d->c->cache;
798
799 sysfs_remove_link(&d->c->kobj, d->name);
800 sysfs_remove_link(&d->kobj, "cache");
801
802 bd_unlink_disk_holder(ca->bdev, d->disk);
803 }
804}
805
806static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
807 const char *name)
808{
809 struct cache *ca = c->cache;
810 int ret;
811
812 bd_link_disk_holder(ca->bdev, d->disk);
813
814 snprintf(d->name, BCACHEDEVNAME_SIZE,
815 "%s%u", name, d->id);
816
817 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
818 if (ret < 0)
819 pr_err("Couldn't create device -> cache set symlink\n");
820
821 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
822 if (ret < 0)
823 pr_err("Couldn't create cache set -> device symlink\n");
824
825 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
826}
827
828static void bcache_device_detach(struct bcache_device *d)
829{
830 lockdep_assert_held(&bch_register_lock);
831
832 atomic_dec(&d->c->attached_dev_nr);
833
834 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
835 struct uuid_entry *u = d->c->uuids + d->id;
836
837 SET_UUID_FLASH_ONLY(u, 0);
838 memcpy(u->uuid, invalid_uuid, 16);
839 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
840 bch_uuid_write(d->c);
841 }
842
843 bcache_device_unlink(d);
844
845 d->c->devices[d->id] = NULL;
846 closure_put(&d->c->caching);
847 d->c = NULL;
848}
849
850static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
851 unsigned int id)
852{
853 d->id = id;
854 d->c = c;
855 c->devices[id] = d;
856
857 if (id >= c->devices_max_used)
858 c->devices_max_used = id + 1;
859
860 closure_get(&c->caching);
861}
862
863static inline int first_minor_to_idx(int first_minor)
864{
865 return (first_minor/BCACHE_MINORS);
866}
867
868static inline int idx_to_first_minor(int idx)
869{
870 return (idx * BCACHE_MINORS);
871}
872
873static void bcache_device_free(struct bcache_device *d)
874{
875 struct gendisk *disk = d->disk;
876
877 lockdep_assert_held(&bch_register_lock);
878
879 if (disk)
880 pr_info("%s stopped\n", disk->disk_name);
881 else
882 pr_err("bcache device (NULL gendisk) stopped\n");
883
884 if (d->c)
885 bcache_device_detach(d);
886
887 if (disk) {
888 bool disk_added = (disk->flags & GENHD_FL_UP) != 0;
889
890 if (disk_added)
891 del_gendisk(disk);
892
893 blk_cleanup_disk(disk);
894 ida_simple_remove(&bcache_device_idx,
895 first_minor_to_idx(disk->first_minor));
896 }
897
898 bioset_exit(&d->bio_split);
899 kvfree(d->full_dirty_stripes);
900 kvfree(d->stripe_sectors_dirty);
901
902 closure_debug_destroy(&d->cl);
903}
904
905static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
906 sector_t sectors, struct block_device *cached_bdev,
907 const struct block_device_operations *ops)
908{
909 struct request_queue *q;
910 const size_t max_stripes = min_t(size_t, INT_MAX,
911 SIZE_MAX / sizeof(atomic_t));
912 uint64_t n;
913 int idx;
914
915 if (!d->stripe_size)
916 d->stripe_size = 1 << 31;
917
918 n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
919 if (!n || n > max_stripes) {
920 pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
921 n);
922 return -ENOMEM;
923 }
924 d->nr_stripes = n;
925
926 n = d->nr_stripes * sizeof(atomic_t);
927 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
928 if (!d->stripe_sectors_dirty)
929 return -ENOMEM;
930
931 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
932 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
933 if (!d->full_dirty_stripes)
934 goto out_free_stripe_sectors_dirty;
935
936 idx = ida_simple_get(&bcache_device_idx, 0,
937 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
938 if (idx < 0)
939 goto out_free_full_dirty_stripes;
940
941 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
942 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
943 goto out_ida_remove;
944
945 d->disk = blk_alloc_disk(NUMA_NO_NODE);
946 if (!d->disk)
947 goto out_bioset_exit;
948
949 set_capacity(d->disk, sectors);
950 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
951
952 d->disk->major = bcache_major;
953 d->disk->first_minor = idx_to_first_minor(idx);
954 d->disk->minors = BCACHE_MINORS;
955 d->disk->fops = ops;
956 d->disk->private_data = d;
957
958 q = d->disk->queue;
959 q->limits.max_hw_sectors = UINT_MAX;
960 q->limits.max_sectors = UINT_MAX;
961 q->limits.max_segment_size = UINT_MAX;
962 q->limits.max_segments = BIO_MAX_VECS;
963 blk_queue_max_discard_sectors(q, UINT_MAX);
964 q->limits.discard_granularity = 512;
965 q->limits.io_min = block_size;
966 q->limits.logical_block_size = block_size;
967 q->limits.physical_block_size = block_size;
968
969 if (q->limits.logical_block_size > PAGE_SIZE && cached_bdev) {
970 /*
971 * This should only happen with BCACHE_SB_VERSION_BDEV.
972 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
973 */
974 pr_info("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
975 d->disk->disk_name, q->limits.logical_block_size,
976 PAGE_SIZE, bdev_logical_block_size(cached_bdev));
977
978 /* This also adjusts physical block size/min io size if needed */
979 blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev));
980 }
981
982 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
983 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
984 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
985
986 blk_queue_write_cache(q, true, true);
987
988 return 0;
989
990out_bioset_exit:
991 bioset_exit(&d->bio_split);
992out_ida_remove:
993 ida_simple_remove(&bcache_device_idx, idx);
994out_free_full_dirty_stripes:
995 kvfree(d->full_dirty_stripes);
996out_free_stripe_sectors_dirty:
997 kvfree(d->stripe_sectors_dirty);
998 return -ENOMEM;
999
1000}
1001
1002/* Cached device */
1003
1004static void calc_cached_dev_sectors(struct cache_set *c)
1005{
1006 uint64_t sectors = 0;
1007 struct cached_dev *dc;
1008
1009 list_for_each_entry(dc, &c->cached_devs, list)
1010 sectors += bdev_sectors(dc->bdev);
1011
1012 c->cached_dev_sectors = sectors;
1013}
1014
1015#define BACKING_DEV_OFFLINE_TIMEOUT 5
1016static int cached_dev_status_update(void *arg)
1017{
1018 struct cached_dev *dc = arg;
1019 struct request_queue *q;
1020
1021 /*
1022 * If this delayed worker is stopping outside, directly quit here.
1023 * dc->io_disable might be set via sysfs interface, so check it
1024 * here too.
1025 */
1026 while (!kthread_should_stop() && !dc->io_disable) {
1027 q = bdev_get_queue(dc->bdev);
1028 if (blk_queue_dying(q))
1029 dc->offline_seconds++;
1030 else
1031 dc->offline_seconds = 0;
1032
1033 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1034 pr_err("%s: device offline for %d seconds\n",
1035 dc->backing_dev_name,
1036 BACKING_DEV_OFFLINE_TIMEOUT);
1037 pr_err("%s: disable I/O request due to backing device offline\n",
1038 dc->disk.name);
1039 dc->io_disable = true;
1040 /* let others know earlier that io_disable is true */
1041 smp_mb();
1042 bcache_device_stop(&dc->disk);
1043 break;
1044 }
1045 schedule_timeout_interruptible(HZ);
1046 }
1047
1048 wait_for_kthread_stop();
1049 return 0;
1050}
1051
1052
1053int bch_cached_dev_run(struct cached_dev *dc)
1054{
1055 int ret = 0;
1056 struct bcache_device *d = &dc->disk;
1057 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1058 char *env[] = {
1059 "DRIVER=bcache",
1060 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1061 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1062 NULL,
1063 };
1064
1065 if (dc->io_disable) {
1066 pr_err("I/O disabled on cached dev %s\n",
1067 dc->backing_dev_name);
1068 ret = -EIO;
1069 goto out;
1070 }
1071
1072 if (atomic_xchg(&dc->running, 1)) {
1073 pr_info("cached dev %s is running already\n",
1074 dc->backing_dev_name);
1075 ret = -EBUSY;
1076 goto out;
1077 }
1078
1079 if (!d->c &&
1080 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1081 struct closure cl;
1082
1083 closure_init_stack(&cl);
1084
1085 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1086 bch_write_bdev_super(dc, &cl);
1087 closure_sync(&cl);
1088 }
1089
1090 add_disk(d->disk);
1091 bd_link_disk_holder(dc->bdev, dc->disk.disk);
1092 /*
1093 * won't show up in the uevent file, use udevadm monitor -e instead
1094 * only class / kset properties are persistent
1095 */
1096 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1097
1098 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1099 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1100 &d->kobj, "bcache")) {
1101 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1102 ret = -ENOMEM;
1103 goto out;
1104 }
1105
1106 dc->status_update_thread = kthread_run(cached_dev_status_update,
1107 dc, "bcache_status_update");
1108 if (IS_ERR(dc->status_update_thread)) {
1109 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1110 }
1111
1112out:
1113 kfree(env[1]);
1114 kfree(env[2]);
1115 kfree(buf);
1116 return ret;
1117}
1118
1119/*
1120 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1121 * work dc->writeback_rate_update is running. Wait until the routine
1122 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1123 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1124 * seconds, give up waiting here and continue to cancel it too.
1125 */
1126static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1127{
1128 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1129
1130 do {
1131 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1132 &dc->disk.flags))
1133 break;
1134 time_out--;
1135 schedule_timeout_interruptible(1);
1136 } while (time_out > 0);
1137
1138 if (time_out == 0)
1139 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1140
1141 cancel_delayed_work_sync(&dc->writeback_rate_update);
1142}
1143
1144static void cached_dev_detach_finish(struct work_struct *w)
1145{
1146 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1147
1148 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1149 BUG_ON(refcount_read(&dc->count));
1150
1151
1152 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1153 cancel_writeback_rate_update_dwork(dc);
1154
1155 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1156 kthread_stop(dc->writeback_thread);
1157 dc->writeback_thread = NULL;
1158 }
1159
1160 mutex_lock(&bch_register_lock);
1161
1162 calc_cached_dev_sectors(dc->disk.c);
1163 bcache_device_detach(&dc->disk);
1164 list_move(&dc->list, &uncached_devices);
1165
1166 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1167 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1168
1169 mutex_unlock(&bch_register_lock);
1170
1171 pr_info("Caching disabled for %s\n", dc->backing_dev_name);
1172
1173 /* Drop ref we took in cached_dev_detach() */
1174 closure_put(&dc->disk.cl);
1175}
1176
1177void bch_cached_dev_detach(struct cached_dev *dc)
1178{
1179 lockdep_assert_held(&bch_register_lock);
1180
1181 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1182 return;
1183
1184 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1185 return;
1186
1187 /*
1188 * Block the device from being closed and freed until we're finished
1189 * detaching
1190 */
1191 closure_get(&dc->disk.cl);
1192
1193 bch_writeback_queue(dc);
1194
1195 cached_dev_put(dc);
1196}
1197
1198int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1199 uint8_t *set_uuid)
1200{
1201 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1202 struct uuid_entry *u;
1203 struct cached_dev *exist_dc, *t;
1204 int ret = 0;
1205
1206 if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
1207 (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
1208 return -ENOENT;
1209
1210 if (dc->disk.c) {
1211 pr_err("Can't attach %s: already attached\n",
1212 dc->backing_dev_name);
1213 return -EINVAL;
1214 }
1215
1216 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1217 pr_err("Can't attach %s: shutting down\n",
1218 dc->backing_dev_name);
1219 return -EINVAL;
1220 }
1221
1222 if (dc->sb.block_size < c->cache->sb.block_size) {
1223 /* Will die */
1224 pr_err("Couldn't attach %s: block size less than set's block size\n",
1225 dc->backing_dev_name);
1226 return -EINVAL;
1227 }
1228
1229 /* Check whether already attached */
1230 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1231 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1232 pr_err("Tried to attach %s but duplicate UUID already attached\n",
1233 dc->backing_dev_name);
1234
1235 return -EINVAL;
1236 }
1237 }
1238
1239 u = uuid_find(c, dc->sb.uuid);
1240
1241 if (u &&
1242 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1243 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1244 memcpy(u->uuid, invalid_uuid, 16);
1245 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1246 u = NULL;
1247 }
1248
1249 if (!u) {
1250 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1251 pr_err("Couldn't find uuid for %s in set\n",
1252 dc->backing_dev_name);
1253 return -ENOENT;
1254 }
1255
1256 u = uuid_find_empty(c);
1257 if (!u) {
1258 pr_err("Not caching %s, no room for UUID\n",
1259 dc->backing_dev_name);
1260 return -EINVAL;
1261 }
1262 }
1263
1264 /*
1265 * Deadlocks since we're called via sysfs...
1266 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1267 */
1268
1269 if (bch_is_zero(u->uuid, 16)) {
1270 struct closure cl;
1271
1272 closure_init_stack(&cl);
1273
1274 memcpy(u->uuid, dc->sb.uuid, 16);
1275 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1276 u->first_reg = u->last_reg = rtime;
1277 bch_uuid_write(c);
1278
1279 memcpy(dc->sb.set_uuid, c->set_uuid, 16);
1280 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1281
1282 bch_write_bdev_super(dc, &cl);
1283 closure_sync(&cl);
1284 } else {
1285 u->last_reg = rtime;
1286 bch_uuid_write(c);
1287 }
1288
1289 bcache_device_attach(&dc->disk, c, u - c->uuids);
1290 list_move(&dc->list, &c->cached_devs);
1291 calc_cached_dev_sectors(c);
1292
1293 /*
1294 * dc->c must be set before dc->count != 0 - paired with the mb in
1295 * cached_dev_get()
1296 */
1297 smp_wmb();
1298 refcount_set(&dc->count, 1);
1299
1300 /* Block writeback thread, but spawn it */
1301 down_write(&dc->writeback_lock);
1302 if (bch_cached_dev_writeback_start(dc)) {
1303 up_write(&dc->writeback_lock);
1304 pr_err("Couldn't start writeback facilities for %s\n",
1305 dc->disk.disk->disk_name);
1306 return -ENOMEM;
1307 }
1308
1309 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1310 atomic_set(&dc->has_dirty, 1);
1311 bch_writeback_queue(dc);
1312 }
1313
1314 bch_sectors_dirty_init(&dc->disk);
1315
1316 ret = bch_cached_dev_run(dc);
1317 if (ret && (ret != -EBUSY)) {
1318 up_write(&dc->writeback_lock);
1319 /*
1320 * bch_register_lock is held, bcache_device_stop() is not
1321 * able to be directly called. The kthread and kworker
1322 * created previously in bch_cached_dev_writeback_start()
1323 * have to be stopped manually here.
1324 */
1325 kthread_stop(dc->writeback_thread);
1326 cancel_writeback_rate_update_dwork(dc);
1327 pr_err("Couldn't run cached device %s\n",
1328 dc->backing_dev_name);
1329 return ret;
1330 }
1331
1332 bcache_device_link(&dc->disk, c, "bdev");
1333 atomic_inc(&c->attached_dev_nr);
1334
1335 if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
1336 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1337 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1338 set_disk_ro(dc->disk.disk, 1);
1339 }
1340
1341 /* Allow the writeback thread to proceed */
1342 up_write(&dc->writeback_lock);
1343
1344 pr_info("Caching %s as %s on set %pU\n",
1345 dc->backing_dev_name,
1346 dc->disk.disk->disk_name,
1347 dc->disk.c->set_uuid);
1348 return 0;
1349}
1350
1351/* when dc->disk.kobj released */
1352void bch_cached_dev_release(struct kobject *kobj)
1353{
1354 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1355 disk.kobj);
1356 kfree(dc);
1357 module_put(THIS_MODULE);
1358}
1359
1360static void cached_dev_free(struct closure *cl)
1361{
1362 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1363
1364 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1365 cancel_writeback_rate_update_dwork(dc);
1366
1367 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1368 kthread_stop(dc->writeback_thread);
1369 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1370 kthread_stop(dc->status_update_thread);
1371
1372 mutex_lock(&bch_register_lock);
1373
1374 if (atomic_read(&dc->running))
1375 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1376 bcache_device_free(&dc->disk);
1377 list_del(&dc->list);
1378
1379 mutex_unlock(&bch_register_lock);
1380
1381 if (dc->sb_disk)
1382 put_page(virt_to_page(dc->sb_disk));
1383
1384 if (!IS_ERR_OR_NULL(dc->bdev))
1385 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1386
1387 wake_up(&unregister_wait);
1388
1389 kobject_put(&dc->disk.kobj);
1390}
1391
1392static void cached_dev_flush(struct closure *cl)
1393{
1394 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1395 struct bcache_device *d = &dc->disk;
1396
1397 mutex_lock(&bch_register_lock);
1398 bcache_device_unlink(d);
1399 mutex_unlock(&bch_register_lock);
1400
1401 bch_cache_accounting_destroy(&dc->accounting);
1402 kobject_del(&d->kobj);
1403
1404 continue_at(cl, cached_dev_free, system_wq);
1405}
1406
1407static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1408{
1409 int ret;
1410 struct io *io;
1411 struct request_queue *q = bdev_get_queue(dc->bdev);
1412
1413 __module_get(THIS_MODULE);
1414 INIT_LIST_HEAD(&dc->list);
1415 closure_init(&dc->disk.cl, NULL);
1416 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1417 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1418 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1419 sema_init(&dc->sb_write_mutex, 1);
1420 INIT_LIST_HEAD(&dc->io_lru);
1421 spin_lock_init(&dc->io_lock);
1422 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1423
1424 dc->sequential_cutoff = 4 << 20;
1425
1426 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1427 list_add(&io->lru, &dc->io_lru);
1428 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1429 }
1430
1431 dc->disk.stripe_size = q->limits.io_opt >> 9;
1432
1433 if (dc->disk.stripe_size)
1434 dc->partial_stripes_expensive =
1435 q->limits.raid_partial_stripes_expensive;
1436
1437 ret = bcache_device_init(&dc->disk, block_size,
1438 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
1439 dc->bdev, &bcache_cached_ops);
1440 if (ret)
1441 return ret;
1442
1443 blk_queue_io_opt(dc->disk.disk->queue,
1444 max(queue_io_opt(dc->disk.disk->queue), queue_io_opt(q)));
1445
1446 atomic_set(&dc->io_errors, 0);
1447 dc->io_disable = false;
1448 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1449 /* default to auto */
1450 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1451
1452 bch_cached_dev_request_init(dc);
1453 bch_cached_dev_writeback_init(dc);
1454 return 0;
1455}
1456
1457/* Cached device - bcache superblock */
1458
1459static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1460 struct block_device *bdev,
1461 struct cached_dev *dc)
1462{
1463 const char *err = "cannot allocate memory";
1464 struct cache_set *c;
1465 int ret = -ENOMEM;
1466
1467 bdevname(bdev, dc->backing_dev_name);
1468 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1469 dc->bdev = bdev;
1470 dc->bdev->bd_holder = dc;
1471 dc->sb_disk = sb_disk;
1472
1473 if (cached_dev_init(dc, sb->block_size << 9))
1474 goto err;
1475
1476 err = "error creating kobject";
1477 if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache"))
1478 goto err;
1479 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1480 goto err;
1481
1482 pr_info("registered backing device %s\n", dc->backing_dev_name);
1483
1484 list_add(&dc->list, &uncached_devices);
1485 /* attach to a matched cache set if it exists */
1486 list_for_each_entry(c, &bch_cache_sets, list)
1487 bch_cached_dev_attach(dc, c, NULL);
1488
1489 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1490 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1491 err = "failed to run cached device";
1492 ret = bch_cached_dev_run(dc);
1493 if (ret)
1494 goto err;
1495 }
1496
1497 return 0;
1498err:
1499 pr_notice("error %s: %s\n", dc->backing_dev_name, err);
1500 bcache_device_stop(&dc->disk);
1501 return ret;
1502}
1503
1504/* Flash only volumes */
1505
1506/* When d->kobj released */
1507void bch_flash_dev_release(struct kobject *kobj)
1508{
1509 struct bcache_device *d = container_of(kobj, struct bcache_device,
1510 kobj);
1511 kfree(d);
1512}
1513
1514static void flash_dev_free(struct closure *cl)
1515{
1516 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1517
1518 mutex_lock(&bch_register_lock);
1519 atomic_long_sub(bcache_dev_sectors_dirty(d),
1520 &d->c->flash_dev_dirty_sectors);
1521 bcache_device_free(d);
1522 mutex_unlock(&bch_register_lock);
1523 kobject_put(&d->kobj);
1524}
1525
1526static void flash_dev_flush(struct closure *cl)
1527{
1528 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1529
1530 mutex_lock(&bch_register_lock);
1531 bcache_device_unlink(d);
1532 mutex_unlock(&bch_register_lock);
1533 kobject_del(&d->kobj);
1534 continue_at(cl, flash_dev_free, system_wq);
1535}
1536
1537static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1538{
1539 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1540 GFP_KERNEL);
1541 if (!d)
1542 return -ENOMEM;
1543
1544 closure_init(&d->cl, NULL);
1545 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1546
1547 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1548
1549 if (bcache_device_init(d, block_bytes(c->cache), u->sectors,
1550 NULL, &bcache_flash_ops))
1551 goto err;
1552
1553 bcache_device_attach(d, c, u - c->uuids);
1554 bch_sectors_dirty_init(d);
1555 bch_flash_dev_request_init(d);
1556 add_disk(d->disk);
1557
1558 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1559 goto err;
1560
1561 bcache_device_link(d, c, "volume");
1562
1563 if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
1564 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1565 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1566 set_disk_ro(d->disk, 1);
1567 }
1568
1569 return 0;
1570err:
1571 kobject_put(&d->kobj);
1572 return -ENOMEM;
1573}
1574
1575static int flash_devs_run(struct cache_set *c)
1576{
1577 int ret = 0;
1578 struct uuid_entry *u;
1579
1580 for (u = c->uuids;
1581 u < c->uuids + c->nr_uuids && !ret;
1582 u++)
1583 if (UUID_FLASH_ONLY(u))
1584 ret = flash_dev_run(c, u);
1585
1586 return ret;
1587}
1588
1589int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1590{
1591 struct uuid_entry *u;
1592
1593 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1594 return -EINTR;
1595
1596 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1597 return -EPERM;
1598
1599 u = uuid_find_empty(c);
1600 if (!u) {
1601 pr_err("Can't create volume, no room for UUID\n");
1602 return -EINVAL;
1603 }
1604
1605 get_random_bytes(u->uuid, 16);
1606 memset(u->label, 0, 32);
1607 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1608
1609 SET_UUID_FLASH_ONLY(u, 1);
1610 u->sectors = size >> 9;
1611
1612 bch_uuid_write(c);
1613
1614 return flash_dev_run(c, u);
1615}
1616
1617bool bch_cached_dev_error(struct cached_dev *dc)
1618{
1619 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1620 return false;
1621
1622 dc->io_disable = true;
1623 /* make others know io_disable is true earlier */
1624 smp_mb();
1625
1626 pr_err("stop %s: too many IO errors on backing device %s\n",
1627 dc->disk.disk->disk_name, dc->backing_dev_name);
1628
1629 bcache_device_stop(&dc->disk);
1630 return true;
1631}
1632
1633/* Cache set */
1634
1635__printf(2, 3)
1636bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1637{
1638 struct va_format vaf;
1639 va_list args;
1640
1641 if (c->on_error != ON_ERROR_PANIC &&
1642 test_bit(CACHE_SET_STOPPING, &c->flags))
1643 return false;
1644
1645 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1646 pr_info("CACHE_SET_IO_DISABLE already set\n");
1647
1648 /*
1649 * XXX: we can be called from atomic context
1650 * acquire_console_sem();
1651 */
1652
1653 va_start(args, fmt);
1654
1655 vaf.fmt = fmt;
1656 vaf.va = &args;
1657
1658 pr_err("error on %pU: %pV, disabling caching\n",
1659 c->set_uuid, &vaf);
1660
1661 va_end(args);
1662
1663 if (c->on_error == ON_ERROR_PANIC)
1664 panic("panic forced after error\n");
1665
1666 bch_cache_set_unregister(c);
1667 return true;
1668}
1669
1670/* When c->kobj released */
1671void bch_cache_set_release(struct kobject *kobj)
1672{
1673 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1674
1675 kfree(c);
1676 module_put(THIS_MODULE);
1677}
1678
1679static void cache_set_free(struct closure *cl)
1680{
1681 struct cache_set *c = container_of(cl, struct cache_set, cl);
1682 struct cache *ca;
1683
1684 debugfs_remove(c->debug);
1685
1686 bch_open_buckets_free(c);
1687 bch_btree_cache_free(c);
1688 bch_journal_free(c);
1689
1690 mutex_lock(&bch_register_lock);
1691 bch_bset_sort_state_free(&c->sort);
1692 free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
1693
1694 ca = c->cache;
1695 if (ca) {
1696 ca->set = NULL;
1697 c->cache = NULL;
1698 kobject_put(&ca->kobj);
1699 }
1700
1701
1702 if (c->moving_gc_wq)
1703 destroy_workqueue(c->moving_gc_wq);
1704 bioset_exit(&c->bio_split);
1705 mempool_exit(&c->fill_iter);
1706 mempool_exit(&c->bio_meta);
1707 mempool_exit(&c->search);
1708 kfree(c->devices);
1709
1710 list_del(&c->list);
1711 mutex_unlock(&bch_register_lock);
1712
1713 pr_info("Cache set %pU unregistered\n", c->set_uuid);
1714 wake_up(&unregister_wait);
1715
1716 closure_debug_destroy(&c->cl);
1717 kobject_put(&c->kobj);
1718}
1719
1720static void cache_set_flush(struct closure *cl)
1721{
1722 struct cache_set *c = container_of(cl, struct cache_set, caching);
1723 struct cache *ca = c->cache;
1724 struct btree *b;
1725
1726 bch_cache_accounting_destroy(&c->accounting);
1727
1728 kobject_put(&c->internal);
1729 kobject_del(&c->kobj);
1730
1731 if (!IS_ERR_OR_NULL(c->gc_thread))
1732 kthread_stop(c->gc_thread);
1733
1734 if (!IS_ERR_OR_NULL(c->root))
1735 list_add(&c->root->list, &c->btree_cache);
1736
1737 /*
1738 * Avoid flushing cached nodes if cache set is retiring
1739 * due to too many I/O errors detected.
1740 */
1741 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1742 list_for_each_entry(b, &c->btree_cache, list) {
1743 mutex_lock(&b->write_lock);
1744 if (btree_node_dirty(b))
1745 __bch_btree_node_write(b, NULL);
1746 mutex_unlock(&b->write_lock);
1747 }
1748
1749 if (ca->alloc_thread)
1750 kthread_stop(ca->alloc_thread);
1751
1752 if (c->journal.cur) {
1753 cancel_delayed_work_sync(&c->journal.work);
1754 /* flush last journal entry if needed */
1755 c->journal.work.work.func(&c->journal.work.work);
1756 }
1757
1758 closure_return(cl);
1759}
1760
1761/*
1762 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1763 * cache set is unregistering due to too many I/O errors. In this condition,
1764 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1765 * value and whether the broken cache has dirty data:
1766 *
1767 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1768 * BCH_CACHED_STOP_AUTO 0 NO
1769 * BCH_CACHED_STOP_AUTO 1 YES
1770 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1771 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1772 *
1773 * The expected behavior is, if stop_when_cache_set_failed is configured to
1774 * "auto" via sysfs interface, the bcache device will not be stopped if the
1775 * backing device is clean on the broken cache device.
1776 */
1777static void conditional_stop_bcache_device(struct cache_set *c,
1778 struct bcache_device *d,
1779 struct cached_dev *dc)
1780{
1781 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1782 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1783 d->disk->disk_name, c->set_uuid);
1784 bcache_device_stop(d);
1785 } else if (atomic_read(&dc->has_dirty)) {
1786 /*
1787 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1788 * and dc->has_dirty == 1
1789 */
1790 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1791 d->disk->disk_name);
1792 /*
1793 * There might be a small time gap that cache set is
1794 * released but bcache device is not. Inside this time
1795 * gap, regular I/O requests will directly go into
1796 * backing device as no cache set attached to. This
1797 * behavior may also introduce potential inconsistence
1798 * data in writeback mode while cache is dirty.
1799 * Therefore before calling bcache_device_stop() due
1800 * to a broken cache device, dc->io_disable should be
1801 * explicitly set to true.
1802 */
1803 dc->io_disable = true;
1804 /* make others know io_disable is true earlier */
1805 smp_mb();
1806 bcache_device_stop(d);
1807 } else {
1808 /*
1809 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1810 * and dc->has_dirty == 0
1811 */
1812 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1813 d->disk->disk_name);
1814 }
1815}
1816
1817static void __cache_set_unregister(struct closure *cl)
1818{
1819 struct cache_set *c = container_of(cl, struct cache_set, caching);
1820 struct cached_dev *dc;
1821 struct bcache_device *d;
1822 size_t i;
1823
1824 mutex_lock(&bch_register_lock);
1825
1826 for (i = 0; i < c->devices_max_used; i++) {
1827 d = c->devices[i];
1828 if (!d)
1829 continue;
1830
1831 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1832 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1833 dc = container_of(d, struct cached_dev, disk);
1834 bch_cached_dev_detach(dc);
1835 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1836 conditional_stop_bcache_device(c, d, dc);
1837 } else {
1838 bcache_device_stop(d);
1839 }
1840 }
1841
1842 mutex_unlock(&bch_register_lock);
1843
1844 continue_at(cl, cache_set_flush, system_wq);
1845}
1846
1847void bch_cache_set_stop(struct cache_set *c)
1848{
1849 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1850 /* closure_fn set to __cache_set_unregister() */
1851 closure_queue(&c->caching);
1852}
1853
1854void bch_cache_set_unregister(struct cache_set *c)
1855{
1856 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1857 bch_cache_set_stop(c);
1858}
1859
1860#define alloc_meta_bucket_pages(gfp, sb) \
1861 ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1862
1863struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1864{
1865 int iter_size;
1866 struct cache *ca = container_of(sb, struct cache, sb);
1867 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1868
1869 if (!c)
1870 return NULL;
1871
1872 __module_get(THIS_MODULE);
1873 closure_init(&c->cl, NULL);
1874 set_closure_fn(&c->cl, cache_set_free, system_wq);
1875
1876 closure_init(&c->caching, &c->cl);
1877 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1878
1879 /* Maybe create continue_at_noreturn() and use it here? */
1880 closure_set_stopped(&c->cl);
1881 closure_put(&c->cl);
1882
1883 kobject_init(&c->kobj, &bch_cache_set_ktype);
1884 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1885
1886 bch_cache_accounting_init(&c->accounting, &c->cl);
1887
1888 memcpy(c->set_uuid, sb->set_uuid, 16);
1889
1890 c->cache = ca;
1891 c->cache->set = c;
1892 c->bucket_bits = ilog2(sb->bucket_size);
1893 c->block_bits = ilog2(sb->block_size);
1894 c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
1895 c->devices_max_used = 0;
1896 atomic_set(&c->attached_dev_nr, 0);
1897 c->btree_pages = meta_bucket_pages(sb);
1898 if (c->btree_pages > BTREE_MAX_PAGES)
1899 c->btree_pages = max_t(int, c->btree_pages / 4,
1900 BTREE_MAX_PAGES);
1901
1902 sema_init(&c->sb_write_mutex, 1);
1903 mutex_init(&c->bucket_lock);
1904 init_waitqueue_head(&c->btree_cache_wait);
1905 spin_lock_init(&c->btree_cannibalize_lock);
1906 init_waitqueue_head(&c->bucket_wait);
1907 init_waitqueue_head(&c->gc_wait);
1908 sema_init(&c->uuid_write_mutex, 1);
1909
1910 spin_lock_init(&c->btree_gc_time.lock);
1911 spin_lock_init(&c->btree_split_time.lock);
1912 spin_lock_init(&c->btree_read_time.lock);
1913
1914 bch_moving_init_cache_set(c);
1915
1916 INIT_LIST_HEAD(&c->list);
1917 INIT_LIST_HEAD(&c->cached_devs);
1918 INIT_LIST_HEAD(&c->btree_cache);
1919 INIT_LIST_HEAD(&c->btree_cache_freeable);
1920 INIT_LIST_HEAD(&c->btree_cache_freed);
1921 INIT_LIST_HEAD(&c->data_buckets);
1922
1923 iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
1924 sizeof(struct btree_iter_set);
1925
1926 c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1927 if (!c->devices)
1928 goto err;
1929
1930 if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1931 goto err;
1932
1933 if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1934 sizeof(struct bbio) +
1935 sizeof(struct bio_vec) * meta_bucket_pages(sb)))
1936 goto err;
1937
1938 if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1939 goto err;
1940
1941 if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1942 BIOSET_NEED_RESCUER))
1943 goto err;
1944
1945 c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
1946 if (!c->uuids)
1947 goto err;
1948
1949 c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
1950 if (!c->moving_gc_wq)
1951 goto err;
1952
1953 if (bch_journal_alloc(c))
1954 goto err;
1955
1956 if (bch_btree_cache_alloc(c))
1957 goto err;
1958
1959 if (bch_open_buckets_alloc(c))
1960 goto err;
1961
1962 if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1963 goto err;
1964
1965 c->congested_read_threshold_us = 2000;
1966 c->congested_write_threshold_us = 20000;
1967 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1968 c->idle_max_writeback_rate_enabled = 1;
1969 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1970
1971 return c;
1972err:
1973 bch_cache_set_unregister(c);
1974 return NULL;
1975}
1976
1977static int run_cache_set(struct cache_set *c)
1978{
1979 const char *err = "cannot allocate memory";
1980 struct cached_dev *dc, *t;
1981 struct cache *ca = c->cache;
1982 struct closure cl;
1983 LIST_HEAD(journal);
1984 struct journal_replay *l;
1985
1986 closure_init_stack(&cl);
1987
1988 c->nbuckets = ca->sb.nbuckets;
1989 set_gc_sectors(c);
1990
1991 if (CACHE_SYNC(&c->cache->sb)) {
1992 struct bkey *k;
1993 struct jset *j;
1994
1995 err = "cannot allocate memory for journal";
1996 if (bch_journal_read(c, &journal))
1997 goto err;
1998
1999 pr_debug("btree_journal_read() done\n");
2000
2001 err = "no journal entries found";
2002 if (list_empty(&journal))
2003 goto err;
2004
2005 j = &list_entry(journal.prev, struct journal_replay, list)->j;
2006
2007 err = "IO error reading priorities";
2008 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2009 goto err;
2010
2011 /*
2012 * If prio_read() fails it'll call cache_set_error and we'll
2013 * tear everything down right away, but if we perhaps checked
2014 * sooner we could avoid journal replay.
2015 */
2016
2017 k = &j->btree_root;
2018
2019 err = "bad btree root";
2020 if (__bch_btree_ptr_invalid(c, k))
2021 goto err;
2022
2023 err = "error reading btree root";
2024 c->root = bch_btree_node_get(c, NULL, k,
2025 j->btree_level,
2026 true, NULL);
2027 if (IS_ERR_OR_NULL(c->root))
2028 goto err;
2029
2030 list_del_init(&c->root->list);
2031 rw_unlock(true, c->root);
2032
2033 err = uuid_read(c, j, &cl);
2034 if (err)
2035 goto err;
2036
2037 err = "error in recovery";
2038 if (bch_btree_check(c))
2039 goto err;
2040
2041 bch_journal_mark(c, &journal);
2042 bch_initial_gc_finish(c);
2043 pr_debug("btree_check() done\n");
2044
2045 /*
2046 * bcache_journal_next() can't happen sooner, or
2047 * btree_gc_finish() will give spurious errors about last_gc >
2048 * gc_gen - this is a hack but oh well.
2049 */
2050 bch_journal_next(&c->journal);
2051
2052 err = "error starting allocator thread";
2053 if (bch_cache_allocator_start(ca))
2054 goto err;
2055
2056 /*
2057 * First place it's safe to allocate: btree_check() and
2058 * btree_gc_finish() have to run before we have buckets to
2059 * allocate, and bch_bucket_alloc_set() might cause a journal
2060 * entry to be written so bcache_journal_next() has to be called
2061 * first.
2062 *
2063 * If the uuids were in the old format we have to rewrite them
2064 * before the next journal entry is written:
2065 */
2066 if (j->version < BCACHE_JSET_VERSION_UUID)
2067 __uuid_write(c);
2068
2069 err = "bcache: replay journal failed";
2070 if (bch_journal_replay(c, &journal))
2071 goto err;
2072 } else {
2073 unsigned int j;
2074
2075 pr_notice("invalidating existing data\n");
2076 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2077 2, SB_JOURNAL_BUCKETS);
2078
2079 for (j = 0; j < ca->sb.keys; j++)
2080 ca->sb.d[j] = ca->sb.first_bucket + j;
2081
2082 bch_initial_gc_finish(c);
2083
2084 err = "error starting allocator thread";
2085 if (bch_cache_allocator_start(ca))
2086 goto err;
2087
2088 mutex_lock(&c->bucket_lock);
2089 bch_prio_write(ca, true);
2090 mutex_unlock(&c->bucket_lock);
2091
2092 err = "cannot allocate new UUID bucket";
2093 if (__uuid_write(c))
2094 goto err;
2095
2096 err = "cannot allocate new btree root";
2097 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2098 if (IS_ERR_OR_NULL(c->root))
2099 goto err;
2100
2101 mutex_lock(&c->root->write_lock);
2102 bkey_copy_key(&c->root->key, &MAX_KEY);
2103 bch_btree_node_write(c->root, &cl);
2104 mutex_unlock(&c->root->write_lock);
2105
2106 bch_btree_set_root(c->root);
2107 rw_unlock(true, c->root);
2108
2109 /*
2110 * We don't want to write the first journal entry until
2111 * everything is set up - fortunately journal entries won't be
2112 * written until the SET_CACHE_SYNC() here:
2113 */
2114 SET_CACHE_SYNC(&c->cache->sb, true);
2115
2116 bch_journal_next(&c->journal);
2117 bch_journal_meta(c, &cl);
2118 }
2119
2120 err = "error starting gc thread";
2121 if (bch_gc_thread_start(c))
2122 goto err;
2123
2124 closure_sync(&cl);
2125 c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
2126 bcache_write_super(c);
2127
2128 if (bch_has_feature_obso_large_bucket(&c->cache->sb))
2129 pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
2130
2131 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2132 bch_cached_dev_attach(dc, c, NULL);
2133
2134 flash_devs_run(c);
2135
2136 set_bit(CACHE_SET_RUNNING, &c->flags);
2137 return 0;
2138err:
2139 while (!list_empty(&journal)) {
2140 l = list_first_entry(&journal, struct journal_replay, list);
2141 list_del(&l->list);
2142 kfree(l);
2143 }
2144
2145 closure_sync(&cl);
2146
2147 bch_cache_set_error(c, "%s", err);
2148
2149 return -EIO;
2150}
2151
2152static const char *register_cache_set(struct cache *ca)
2153{
2154 char buf[12];
2155 const char *err = "cannot allocate memory";
2156 struct cache_set *c;
2157
2158 list_for_each_entry(c, &bch_cache_sets, list)
2159 if (!memcmp(c->set_uuid, ca->sb.set_uuid, 16)) {
2160 if (c->cache)
2161 return "duplicate cache set member";
2162
2163 goto found;
2164 }
2165
2166 c = bch_cache_set_alloc(&ca->sb);
2167 if (!c)
2168 return err;
2169
2170 err = "error creating kobject";
2171 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->set_uuid) ||
2172 kobject_add(&c->internal, &c->kobj, "internal"))
2173 goto err;
2174
2175 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2176 goto err;
2177
2178 bch_debug_init_cache_set(c);
2179
2180 list_add(&c->list, &bch_cache_sets);
2181found:
2182 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2183 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2184 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2185 goto err;
2186
2187 kobject_get(&ca->kobj);
2188 ca->set = c;
2189 ca->set->cache = ca;
2190
2191 err = "failed to run cache set";
2192 if (run_cache_set(c) < 0)
2193 goto err;
2194
2195 return NULL;
2196err:
2197 bch_cache_set_unregister(c);
2198 return err;
2199}
2200
2201/* Cache device */
2202
2203/* When ca->kobj released */
2204void bch_cache_release(struct kobject *kobj)
2205{
2206 struct cache *ca = container_of(kobj, struct cache, kobj);
2207 unsigned int i;
2208
2209 if (ca->set) {
2210 BUG_ON(ca->set->cache != ca);
2211 ca->set->cache = NULL;
2212 }
2213
2214 free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2215 kfree(ca->prio_buckets);
2216 vfree(ca->buckets);
2217
2218 free_heap(&ca->heap);
2219 free_fifo(&ca->free_inc);
2220
2221 for (i = 0; i < RESERVE_NR; i++)
2222 free_fifo(&ca->free[i]);
2223
2224 if (ca->sb_disk)
2225 put_page(virt_to_page(ca->sb_disk));
2226
2227 if (!IS_ERR_OR_NULL(ca->bdev))
2228 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2229
2230 kfree(ca);
2231 module_put(THIS_MODULE);
2232}
2233
2234static int cache_alloc(struct cache *ca)
2235{
2236 size_t free;
2237 size_t btree_buckets;
2238 struct bucket *b;
2239 int ret = -ENOMEM;
2240 const char *err = NULL;
2241
2242 __module_get(THIS_MODULE);
2243 kobject_init(&ca->kobj, &bch_cache_ktype);
2244
2245 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2246
2247 /*
2248 * when ca->sb.njournal_buckets is not zero, journal exists,
2249 * and in bch_journal_replay(), tree node may split,
2250 * so bucket of RESERVE_BTREE type is needed,
2251 * the worst situation is all journal buckets are valid journal,
2252 * and all the keys need to replay,
2253 * so the number of RESERVE_BTREE type buckets should be as much
2254 * as journal buckets
2255 */
2256 btree_buckets = ca->sb.njournal_buckets ?: 8;
2257 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2258 if (!free) {
2259 ret = -EPERM;
2260 err = "ca->sb.nbuckets is too small";
2261 goto err_free;
2262 }
2263
2264 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2265 GFP_KERNEL)) {
2266 err = "ca->free[RESERVE_BTREE] alloc failed";
2267 goto err_btree_alloc;
2268 }
2269
2270 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2271 GFP_KERNEL)) {
2272 err = "ca->free[RESERVE_PRIO] alloc failed";
2273 goto err_prio_alloc;
2274 }
2275
2276 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2277 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2278 goto err_movinggc_alloc;
2279 }
2280
2281 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2282 err = "ca->free[RESERVE_NONE] alloc failed";
2283 goto err_none_alloc;
2284 }
2285
2286 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2287 err = "ca->free_inc alloc failed";
2288 goto err_free_inc_alloc;
2289 }
2290
2291 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2292 err = "ca->heap alloc failed";
2293 goto err_heap_alloc;
2294 }
2295
2296 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2297 ca->sb.nbuckets));
2298 if (!ca->buckets) {
2299 err = "ca->buckets alloc failed";
2300 goto err_buckets_alloc;
2301 }
2302
2303 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2304 prio_buckets(ca), 2),
2305 GFP_KERNEL);
2306 if (!ca->prio_buckets) {
2307 err = "ca->prio_buckets alloc failed";
2308 goto err_prio_buckets_alloc;
2309 }
2310
2311 ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2312 if (!ca->disk_buckets) {
2313 err = "ca->disk_buckets alloc failed";
2314 goto err_disk_buckets_alloc;
2315 }
2316
2317 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2318
2319 for_each_bucket(b, ca)
2320 atomic_set(&b->pin, 0);
2321 return 0;
2322
2323err_disk_buckets_alloc:
2324 kfree(ca->prio_buckets);
2325err_prio_buckets_alloc:
2326 vfree(ca->buckets);
2327err_buckets_alloc:
2328 free_heap(&ca->heap);
2329err_heap_alloc:
2330 free_fifo(&ca->free_inc);
2331err_free_inc_alloc:
2332 free_fifo(&ca->free[RESERVE_NONE]);
2333err_none_alloc:
2334 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2335err_movinggc_alloc:
2336 free_fifo(&ca->free[RESERVE_PRIO]);
2337err_prio_alloc:
2338 free_fifo(&ca->free[RESERVE_BTREE]);
2339err_btree_alloc:
2340err_free:
2341 module_put(THIS_MODULE);
2342 if (err)
2343 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2344 return ret;
2345}
2346
2347static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2348 struct block_device *bdev, struct cache *ca)
2349{
2350 const char *err = NULL; /* must be set for any error case */
2351 int ret = 0;
2352
2353 bdevname(bdev, ca->cache_dev_name);
2354 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2355 ca->bdev = bdev;
2356 ca->bdev->bd_holder = ca;
2357 ca->sb_disk = sb_disk;
2358
2359 if (blk_queue_discard(bdev_get_queue(bdev)))
2360 ca->discard = CACHE_DISCARD(&ca->sb);
2361
2362 ret = cache_alloc(ca);
2363 if (ret != 0) {
2364 /*
2365 * If we failed here, it means ca->kobj is not initialized yet,
2366 * kobject_put() won't be called and there is no chance to
2367 * call blkdev_put() to bdev in bch_cache_release(). So we
2368 * explicitly call blkdev_put() here.
2369 */
2370 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2371 if (ret == -ENOMEM)
2372 err = "cache_alloc(): -ENOMEM";
2373 else if (ret == -EPERM)
2374 err = "cache_alloc(): cache device is too small";
2375 else
2376 err = "cache_alloc(): unknown error";
2377 goto err;
2378 }
2379
2380 if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) {
2381 err = "error calling kobject_add";
2382 ret = -ENOMEM;
2383 goto out;
2384 }
2385
2386 mutex_lock(&bch_register_lock);
2387 err = register_cache_set(ca);
2388 mutex_unlock(&bch_register_lock);
2389
2390 if (err) {
2391 ret = -ENODEV;
2392 goto out;
2393 }
2394
2395 pr_info("registered cache device %s\n", ca->cache_dev_name);
2396
2397out:
2398 kobject_put(&ca->kobj);
2399
2400err:
2401 if (err)
2402 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2403
2404 return ret;
2405}
2406
2407/* Global interfaces/init */
2408
2409static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2410 const char *buffer, size_t size);
2411static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2412 struct kobj_attribute *attr,
2413 const char *buffer, size_t size);
2414
2415kobj_attribute_write(register, register_bcache);
2416kobj_attribute_write(register_quiet, register_bcache);
2417kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2418
2419static bool bch_is_open_backing(dev_t dev)
2420{
2421 struct cache_set *c, *tc;
2422 struct cached_dev *dc, *t;
2423
2424 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2425 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2426 if (dc->bdev->bd_dev == dev)
2427 return true;
2428 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2429 if (dc->bdev->bd_dev == dev)
2430 return true;
2431 return false;
2432}
2433
2434static bool bch_is_open_cache(dev_t dev)
2435{
2436 struct cache_set *c, *tc;
2437
2438 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2439 struct cache *ca = c->cache;
2440
2441 if (ca->bdev->bd_dev == dev)
2442 return true;
2443 }
2444
2445 return false;
2446}
2447
2448static bool bch_is_open(dev_t dev)
2449{
2450 return bch_is_open_cache(dev) || bch_is_open_backing(dev);
2451}
2452
2453struct async_reg_args {
2454 struct delayed_work reg_work;
2455 char *path;
2456 struct cache_sb *sb;
2457 struct cache_sb_disk *sb_disk;
2458 struct block_device *bdev;
2459};
2460
2461static void register_bdev_worker(struct work_struct *work)
2462{
2463 int fail = false;
2464 struct async_reg_args *args =
2465 container_of(work, struct async_reg_args, reg_work.work);
2466 struct cached_dev *dc;
2467
2468 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2469 if (!dc) {
2470 fail = true;
2471 put_page(virt_to_page(args->sb_disk));
2472 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2473 goto out;
2474 }
2475
2476 mutex_lock(&bch_register_lock);
2477 if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
2478 fail = true;
2479 mutex_unlock(&bch_register_lock);
2480
2481out:
2482 if (fail)
2483 pr_info("error %s: fail to register backing device\n",
2484 args->path);
2485 kfree(args->sb);
2486 kfree(args->path);
2487 kfree(args);
2488 module_put(THIS_MODULE);
2489}
2490
2491static void register_cache_worker(struct work_struct *work)
2492{
2493 int fail = false;
2494 struct async_reg_args *args =
2495 container_of(work, struct async_reg_args, reg_work.work);
2496 struct cache *ca;
2497
2498 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2499 if (!ca) {
2500 fail = true;
2501 put_page(virt_to_page(args->sb_disk));
2502 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2503 goto out;
2504 }
2505
2506 /* blkdev_put() will be called in bch_cache_release() */
2507 if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
2508 fail = true;
2509
2510out:
2511 if (fail)
2512 pr_info("error %s: fail to register cache device\n",
2513 args->path);
2514 kfree(args->sb);
2515 kfree(args->path);
2516 kfree(args);
2517 module_put(THIS_MODULE);
2518}
2519
2520static void register_device_async(struct async_reg_args *args)
2521{
2522 if (SB_IS_BDEV(args->sb))
2523 INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2524 else
2525 INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2526
2527 /* 10 jiffies is enough for a delay */
2528 queue_delayed_work(system_wq, &args->reg_work, 10);
2529}
2530
2531static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2532 const char *buffer, size_t size)
2533{
2534 const char *err;
2535 char *path = NULL;
2536 struct cache_sb *sb;
2537 struct cache_sb_disk *sb_disk;
2538 struct block_device *bdev;
2539 ssize_t ret;
2540 bool async_registration = false;
2541
2542#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2543 async_registration = true;
2544#endif
2545
2546 ret = -EBUSY;
2547 err = "failed to reference bcache module";
2548 if (!try_module_get(THIS_MODULE))
2549 goto out;
2550
2551 /* For latest state of bcache_is_reboot */
2552 smp_mb();
2553 err = "bcache is in reboot";
2554 if (bcache_is_reboot)
2555 goto out_module_put;
2556
2557 ret = -ENOMEM;
2558 err = "cannot allocate memory";
2559 path = kstrndup(buffer, size, GFP_KERNEL);
2560 if (!path)
2561 goto out_module_put;
2562
2563 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2564 if (!sb)
2565 goto out_free_path;
2566
2567 ret = -EINVAL;
2568 err = "failed to open device";
2569 bdev = blkdev_get_by_path(strim(path),
2570 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2571 sb);
2572 if (IS_ERR(bdev)) {
2573 if (bdev == ERR_PTR(-EBUSY)) {
2574 dev_t dev;
2575
2576 mutex_lock(&bch_register_lock);
2577 if (lookup_bdev(strim(path), &dev) == 0 &&
2578 bch_is_open(dev))
2579 err = "device already registered";
2580 else
2581 err = "device busy";
2582 mutex_unlock(&bch_register_lock);
2583 if (attr == &ksysfs_register_quiet)
2584 goto done;
2585 }
2586 goto out_free_sb;
2587 }
2588
2589 err = "failed to set blocksize";
2590 if (set_blocksize(bdev, 4096))
2591 goto out_blkdev_put;
2592
2593 err = read_super(sb, bdev, &sb_disk);
2594 if (err)
2595 goto out_blkdev_put;
2596
2597 err = "failed to register device";
2598
2599 if (async_registration) {
2600 /* register in asynchronous way */
2601 struct async_reg_args *args =
2602 kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2603
2604 if (!args) {
2605 ret = -ENOMEM;
2606 err = "cannot allocate memory";
2607 goto out_put_sb_page;
2608 }
2609
2610 args->path = path;
2611 args->sb = sb;
2612 args->sb_disk = sb_disk;
2613 args->bdev = bdev;
2614 register_device_async(args);
2615 /* No wait and returns to user space */
2616 goto async_done;
2617 }
2618
2619 if (SB_IS_BDEV(sb)) {
2620 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2621
2622 if (!dc)
2623 goto out_put_sb_page;
2624
2625 mutex_lock(&bch_register_lock);
2626 ret = register_bdev(sb, sb_disk, bdev, dc);
2627 mutex_unlock(&bch_register_lock);
2628 /* blkdev_put() will be called in cached_dev_free() */
2629 if (ret < 0)
2630 goto out_free_sb;
2631 } else {
2632 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2633
2634 if (!ca)
2635 goto out_put_sb_page;
2636
2637 /* blkdev_put() will be called in bch_cache_release() */
2638 if (register_cache(sb, sb_disk, bdev, ca) != 0)
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 acqurie
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");