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
30 unsigned int bch_cutoff_writeback;
31 unsigned int bch_cutoff_writeback_sync;
32
33 static const char bcache_magic[] = {
34 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
35 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
36 };
37
38 static const char invalid_uuid[] = {
39 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
40 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
41 };
42
43 static struct kobject *bcache_kobj;
44 struct mutex bch_register_lock;
45 bool bcache_is_reboot;
46 LIST_HEAD(bch_cache_sets);
47 static LIST_HEAD(uncached_devices);
48
49 static int bcache_major;
50 static DEFINE_IDA(bcache_device_idx);
51 static wait_queue_head_t unregister_wait;
52 struct workqueue_struct *bcache_wq;
53 struct workqueue_struct *bch_flush_wq;
54 struct 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
get_bucket_size(struct cache_sb * sb,struct cache_sb_disk * s)65 static 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
read_super_common(struct cache_sb * sb,struct block_device * bdev,struct cache_sb_disk * s)92 static 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;
162 err:
163 return err;
164 }
165
166
read_super(struct cache_sb * sb,struct block_device * bdev,struct cache_sb_disk ** res)167 static 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;
275 err:
276 put_page(page);
277 return err;
278 }
279
write_bdev_super_endio(struct bio * bio)280 static 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
__write_super(struct cache_sb * sb,struct cache_sb_disk * out,struct bio * bio)290 static 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
bch_write_bdev_super_unlock(struct closure * cl)331 static 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
bch_write_bdev_super(struct cached_dev * dc,struct closure * parent)338 void 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
write_super_endio(struct bio * bio)358 static 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
bcache_write_super_unlock(struct closure * cl)368 static 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
bcache_write_super(struct cache_set * c)375 void 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
uuid_endio(struct bio * bio)403 static 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
uuid_io_unlock(struct closure * cl)413 static 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
uuid_io(struct cache_set * c,int op,unsigned long op_flags,struct bkey * k,struct closure * parent)420 static 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
uuid_read(struct cache_set * c,struct jset * j,struct closure * cl)461 static 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
__uuid_write(struct cache_set * c)502 static 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
bch_uuid_write(struct cache_set * c)528 int 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
uuid_find(struct cache_set * c,const char * uuid)538 static 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
uuid_find_empty(struct cache_set * c)550 static 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
prio_endio(struct bio * bio)584 static 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
prio_io(struct cache * ca,uint64_t bucket,int op,unsigned long op_flags)593 static 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
bch_prio_write(struct cache * ca,bool wait)614 int 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
prio_read(struct cache * ca,uint64_t bucket)695 static 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;
733 out:
734 return ret;
735 }
736
737 /* Bcache device */
738
open_dev(struct block_device * b,fmode_t mode)739 static 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
release_dev(struct gendisk * b,fmode_t mode)750 static 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
ioctl_dev(struct block_device * b,fmode_t mode,unsigned int cmd,unsigned long arg)757 static 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
765 static 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
773 static 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
bcache_device_stop(struct bcache_device * d)781 void 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
bcache_device_unlink(struct bcache_device * d)792 static 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
bcache_device_link(struct bcache_device * d,struct cache_set * c,const char * name)806 static 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
bcache_device_detach(struct bcache_device * d)828 static 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
bcache_device_attach(struct bcache_device * d,struct cache_set * c,unsigned int id)850 static 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
first_minor_to_idx(int first_minor)863 static inline int first_minor_to_idx(int first_minor)
864 {
865 return (first_minor/BCACHE_MINORS);
866 }
867
idx_to_first_minor(int idx)868 static inline int idx_to_first_minor(int idx)
869 {
870 return (idx * BCACHE_MINORS);
871 }
872
bcache_device_free(struct bcache_device * d)873 static 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 if (disk->queue)
894 blk_cleanup_queue(disk->queue);
895
896 ida_simple_remove(&bcache_device_idx,
897 first_minor_to_idx(disk->first_minor));
898 if (disk_added)
899 put_disk(disk);
900 }
901
902 bioset_exit(&d->bio_split);
903 kvfree(d->full_dirty_stripes);
904 kvfree(d->stripe_sectors_dirty);
905
906 closure_debug_destroy(&d->cl);
907 }
908
bcache_device_init(struct bcache_device * d,unsigned int block_size,sector_t sectors,struct block_device * cached_bdev,const struct block_device_operations * ops)909 static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
910 sector_t sectors, struct block_device *cached_bdev,
911 const struct block_device_operations *ops)
912 {
913 struct request_queue *q;
914 const size_t max_stripes = min_t(size_t, INT_MAX,
915 SIZE_MAX / sizeof(atomic_t));
916 uint64_t n;
917 int idx;
918
919 if (!d->stripe_size)
920 d->stripe_size = 1 << 31;
921
922 n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
923 if (!n || n > max_stripes) {
924 pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
925 n);
926 return -ENOMEM;
927 }
928 d->nr_stripes = n;
929
930 n = d->nr_stripes * sizeof(atomic_t);
931 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
932 if (!d->stripe_sectors_dirty)
933 return -ENOMEM;
934
935 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
936 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
937 if (!d->full_dirty_stripes)
938 return -ENOMEM;
939
940 idx = ida_simple_get(&bcache_device_idx, 0,
941 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
942 if (idx < 0)
943 return idx;
944
945 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
946 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
947 goto err;
948
949 d->disk = alloc_disk(BCACHE_MINORS);
950 if (!d->disk)
951 goto err;
952
953 set_capacity(d->disk, sectors);
954 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
955
956 d->disk->major = bcache_major;
957 d->disk->first_minor = idx_to_first_minor(idx);
958 d->disk->fops = ops;
959 d->disk->private_data = d;
960
961 q = blk_alloc_queue(NUMA_NO_NODE);
962 if (!q)
963 return -ENOMEM;
964
965 d->disk->queue = q;
966 q->limits.max_hw_sectors = UINT_MAX;
967 q->limits.max_sectors = UINT_MAX;
968 q->limits.max_segment_size = UINT_MAX;
969 q->limits.max_segments = BIO_MAX_VECS;
970 blk_queue_max_discard_sectors(q, UINT_MAX);
971 q->limits.discard_granularity = 512;
972 q->limits.io_min = block_size;
973 q->limits.logical_block_size = block_size;
974 q->limits.physical_block_size = block_size;
975
976 if (q->limits.logical_block_size > PAGE_SIZE && cached_bdev) {
977 /*
978 * This should only happen with BCACHE_SB_VERSION_BDEV.
979 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
980 */
981 pr_info("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
982 d->disk->disk_name, q->limits.logical_block_size,
983 PAGE_SIZE, bdev_logical_block_size(cached_bdev));
984
985 /* This also adjusts physical block size/min io size if needed */
986 blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev));
987 }
988
989 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
990 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
991 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
992
993 blk_queue_write_cache(q, true, true);
994
995 return 0;
996
997 err:
998 ida_simple_remove(&bcache_device_idx, idx);
999 return -ENOMEM;
1000
1001 }
1002
1003 /* Cached device */
1004
calc_cached_dev_sectors(struct cache_set * c)1005 static void calc_cached_dev_sectors(struct cache_set *c)
1006 {
1007 uint64_t sectors = 0;
1008 struct cached_dev *dc;
1009
1010 list_for_each_entry(dc, &c->cached_devs, list)
1011 sectors += bdev_sectors(dc->bdev);
1012
1013 c->cached_dev_sectors = sectors;
1014 }
1015
1016 #define BACKING_DEV_OFFLINE_TIMEOUT 5
cached_dev_status_update(void * arg)1017 static int cached_dev_status_update(void *arg)
1018 {
1019 struct cached_dev *dc = arg;
1020 struct request_queue *q;
1021
1022 /*
1023 * If this delayed worker is stopping outside, directly quit here.
1024 * dc->io_disable might be set via sysfs interface, so check it
1025 * here too.
1026 */
1027 while (!kthread_should_stop() && !dc->io_disable) {
1028 q = bdev_get_queue(dc->bdev);
1029 if (blk_queue_dying(q))
1030 dc->offline_seconds++;
1031 else
1032 dc->offline_seconds = 0;
1033
1034 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1035 pr_err("%s: device offline for %d seconds\n",
1036 dc->backing_dev_name,
1037 BACKING_DEV_OFFLINE_TIMEOUT);
1038 pr_err("%s: disable I/O request due to backing device offline\n",
1039 dc->disk.name);
1040 dc->io_disable = true;
1041 /* let others know earlier that io_disable is true */
1042 smp_mb();
1043 bcache_device_stop(&dc->disk);
1044 break;
1045 }
1046 schedule_timeout_interruptible(HZ);
1047 }
1048
1049 wait_for_kthread_stop();
1050 return 0;
1051 }
1052
1053
bch_cached_dev_run(struct cached_dev * dc)1054 int bch_cached_dev_run(struct cached_dev *dc)
1055 {
1056 int ret = 0;
1057 struct bcache_device *d = &dc->disk;
1058 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1059 char *env[] = {
1060 "DRIVER=bcache",
1061 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1062 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1063 NULL,
1064 };
1065
1066 if (dc->io_disable) {
1067 pr_err("I/O disabled on cached dev %s\n",
1068 dc->backing_dev_name);
1069 ret = -EIO;
1070 goto out;
1071 }
1072
1073 if (atomic_xchg(&dc->running, 1)) {
1074 pr_info("cached dev %s is running already\n",
1075 dc->backing_dev_name);
1076 ret = -EBUSY;
1077 goto out;
1078 }
1079
1080 if (!d->c &&
1081 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1082 struct closure cl;
1083
1084 closure_init_stack(&cl);
1085
1086 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1087 bch_write_bdev_super(dc, &cl);
1088 closure_sync(&cl);
1089 }
1090
1091 add_disk(d->disk);
1092 bd_link_disk_holder(dc->bdev, dc->disk.disk);
1093 /*
1094 * won't show up in the uevent file, use udevadm monitor -e instead
1095 * only class / kset properties are persistent
1096 */
1097 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1098
1099 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1100 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1101 &d->kobj, "bcache")) {
1102 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1103 ret = -ENOMEM;
1104 goto out;
1105 }
1106
1107 dc->status_update_thread = kthread_run(cached_dev_status_update,
1108 dc, "bcache_status_update");
1109 if (IS_ERR(dc->status_update_thread)) {
1110 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1111 }
1112
1113 out:
1114 kfree(env[1]);
1115 kfree(env[2]);
1116 kfree(buf);
1117 return ret;
1118 }
1119
1120 /*
1121 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1122 * work dc->writeback_rate_update is running. Wait until the routine
1123 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1124 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1125 * seconds, give up waiting here and continue to cancel it too.
1126 */
cancel_writeback_rate_update_dwork(struct cached_dev * dc)1127 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1128 {
1129 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1130
1131 do {
1132 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1133 &dc->disk.flags))
1134 break;
1135 time_out--;
1136 schedule_timeout_interruptible(1);
1137 } while (time_out > 0);
1138
1139 if (time_out == 0)
1140 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1141
1142 cancel_delayed_work_sync(&dc->writeback_rate_update);
1143 }
1144
cached_dev_detach_finish(struct work_struct * w)1145 static void cached_dev_detach_finish(struct work_struct *w)
1146 {
1147 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1148
1149 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1150 BUG_ON(refcount_read(&dc->count));
1151
1152
1153 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1154 cancel_writeback_rate_update_dwork(dc);
1155
1156 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1157 kthread_stop(dc->writeback_thread);
1158 dc->writeback_thread = NULL;
1159 }
1160
1161 mutex_lock(&bch_register_lock);
1162
1163 calc_cached_dev_sectors(dc->disk.c);
1164 bcache_device_detach(&dc->disk);
1165 list_move(&dc->list, &uncached_devices);
1166
1167 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1168 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1169
1170 mutex_unlock(&bch_register_lock);
1171
1172 pr_info("Caching disabled for %s\n", dc->backing_dev_name);
1173
1174 /* Drop ref we took in cached_dev_detach() */
1175 closure_put(&dc->disk.cl);
1176 }
1177
bch_cached_dev_detach(struct cached_dev * dc)1178 void bch_cached_dev_detach(struct cached_dev *dc)
1179 {
1180 lockdep_assert_held(&bch_register_lock);
1181
1182 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1183 return;
1184
1185 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1186 return;
1187
1188 /*
1189 * Block the device from being closed and freed until we're finished
1190 * detaching
1191 */
1192 closure_get(&dc->disk.cl);
1193
1194 bch_writeback_queue(dc);
1195
1196 cached_dev_put(dc);
1197 }
1198
bch_cached_dev_attach(struct cached_dev * dc,struct cache_set * c,uint8_t * set_uuid)1199 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1200 uint8_t *set_uuid)
1201 {
1202 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1203 struct uuid_entry *u;
1204 struct cached_dev *exist_dc, *t;
1205 int ret = 0;
1206
1207 if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
1208 (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
1209 return -ENOENT;
1210
1211 if (dc->disk.c) {
1212 pr_err("Can't attach %s: already attached\n",
1213 dc->backing_dev_name);
1214 return -EINVAL;
1215 }
1216
1217 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1218 pr_err("Can't attach %s: shutting down\n",
1219 dc->backing_dev_name);
1220 return -EINVAL;
1221 }
1222
1223 if (dc->sb.block_size < c->cache->sb.block_size) {
1224 /* Will die */
1225 pr_err("Couldn't attach %s: block size less than set's block size\n",
1226 dc->backing_dev_name);
1227 return -EINVAL;
1228 }
1229
1230 /* Check whether already attached */
1231 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1232 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1233 pr_err("Tried to attach %s but duplicate UUID already attached\n",
1234 dc->backing_dev_name);
1235
1236 return -EINVAL;
1237 }
1238 }
1239
1240 u = uuid_find(c, dc->sb.uuid);
1241
1242 if (u &&
1243 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1244 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1245 memcpy(u->uuid, invalid_uuid, 16);
1246 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1247 u = NULL;
1248 }
1249
1250 if (!u) {
1251 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1252 pr_err("Couldn't find uuid for %s in set\n",
1253 dc->backing_dev_name);
1254 return -ENOENT;
1255 }
1256
1257 u = uuid_find_empty(c);
1258 if (!u) {
1259 pr_err("Not caching %s, no room for UUID\n",
1260 dc->backing_dev_name);
1261 return -EINVAL;
1262 }
1263 }
1264
1265 /*
1266 * Deadlocks since we're called via sysfs...
1267 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1268 */
1269
1270 if (bch_is_zero(u->uuid, 16)) {
1271 struct closure cl;
1272
1273 closure_init_stack(&cl);
1274
1275 memcpy(u->uuid, dc->sb.uuid, 16);
1276 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1277 u->first_reg = u->last_reg = rtime;
1278 bch_uuid_write(c);
1279
1280 memcpy(dc->sb.set_uuid, c->set_uuid, 16);
1281 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1282
1283 bch_write_bdev_super(dc, &cl);
1284 closure_sync(&cl);
1285 } else {
1286 u->last_reg = rtime;
1287 bch_uuid_write(c);
1288 }
1289
1290 bcache_device_attach(&dc->disk, c, u - c->uuids);
1291 list_move(&dc->list, &c->cached_devs);
1292 calc_cached_dev_sectors(c);
1293
1294 /*
1295 * dc->c must be set before dc->count != 0 - paired with the mb in
1296 * cached_dev_get()
1297 */
1298 smp_wmb();
1299 refcount_set(&dc->count, 1);
1300
1301 /* Block writeback thread, but spawn it */
1302 down_write(&dc->writeback_lock);
1303 if (bch_cached_dev_writeback_start(dc)) {
1304 up_write(&dc->writeback_lock);
1305 pr_err("Couldn't start writeback facilities for %s\n",
1306 dc->disk.disk->disk_name);
1307 return -ENOMEM;
1308 }
1309
1310 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1311 atomic_set(&dc->has_dirty, 1);
1312 bch_writeback_queue(dc);
1313 }
1314
1315 bch_sectors_dirty_init(&dc->disk);
1316
1317 ret = bch_cached_dev_run(dc);
1318 if (ret && (ret != -EBUSY)) {
1319 up_write(&dc->writeback_lock);
1320 /*
1321 * bch_register_lock is held, bcache_device_stop() is not
1322 * able to be directly called. The kthread and kworker
1323 * created previously in bch_cached_dev_writeback_start()
1324 * have to be stopped manually here.
1325 */
1326 kthread_stop(dc->writeback_thread);
1327 cancel_writeback_rate_update_dwork(dc);
1328 pr_err("Couldn't run cached device %s\n",
1329 dc->backing_dev_name);
1330 return ret;
1331 }
1332
1333 bcache_device_link(&dc->disk, c, "bdev");
1334 atomic_inc(&c->attached_dev_nr);
1335
1336 if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
1337 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1338 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1339 set_disk_ro(dc->disk.disk, 1);
1340 }
1341
1342 /* Allow the writeback thread to proceed */
1343 up_write(&dc->writeback_lock);
1344
1345 pr_info("Caching %s as %s on set %pU\n",
1346 dc->backing_dev_name,
1347 dc->disk.disk->disk_name,
1348 dc->disk.c->set_uuid);
1349 return 0;
1350 }
1351
1352 /* when dc->disk.kobj released */
bch_cached_dev_release(struct kobject * kobj)1353 void bch_cached_dev_release(struct kobject *kobj)
1354 {
1355 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1356 disk.kobj);
1357 kfree(dc);
1358 module_put(THIS_MODULE);
1359 }
1360
cached_dev_free(struct closure * cl)1361 static void cached_dev_free(struct closure *cl)
1362 {
1363 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1364
1365 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1366 cancel_writeback_rate_update_dwork(dc);
1367
1368 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1369 kthread_stop(dc->writeback_thread);
1370 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1371 kthread_stop(dc->status_update_thread);
1372
1373 mutex_lock(&bch_register_lock);
1374
1375 if (atomic_read(&dc->running))
1376 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1377 bcache_device_free(&dc->disk);
1378 list_del(&dc->list);
1379
1380 mutex_unlock(&bch_register_lock);
1381
1382 if (dc->sb_disk)
1383 put_page(virt_to_page(dc->sb_disk));
1384
1385 if (!IS_ERR_OR_NULL(dc->bdev))
1386 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1387
1388 wake_up(&unregister_wait);
1389
1390 kobject_put(&dc->disk.kobj);
1391 }
1392
cached_dev_flush(struct closure * cl)1393 static void cached_dev_flush(struct closure *cl)
1394 {
1395 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1396 struct bcache_device *d = &dc->disk;
1397
1398 mutex_lock(&bch_register_lock);
1399 bcache_device_unlink(d);
1400 mutex_unlock(&bch_register_lock);
1401
1402 bch_cache_accounting_destroy(&dc->accounting);
1403 kobject_del(&d->kobj);
1404
1405 continue_at(cl, cached_dev_free, system_wq);
1406 }
1407
cached_dev_init(struct cached_dev * dc,unsigned int block_size)1408 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1409 {
1410 int ret;
1411 struct io *io;
1412 struct request_queue *q = bdev_get_queue(dc->bdev);
1413
1414 __module_get(THIS_MODULE);
1415 INIT_LIST_HEAD(&dc->list);
1416 closure_init(&dc->disk.cl, NULL);
1417 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1418 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1419 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1420 sema_init(&dc->sb_write_mutex, 1);
1421 INIT_LIST_HEAD(&dc->io_lru);
1422 spin_lock_init(&dc->io_lock);
1423 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1424
1425 dc->sequential_cutoff = 4 << 20;
1426
1427 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1428 list_add(&io->lru, &dc->io_lru);
1429 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1430 }
1431
1432 dc->disk.stripe_size = q->limits.io_opt >> 9;
1433
1434 if (dc->disk.stripe_size)
1435 dc->partial_stripes_expensive =
1436 q->limits.raid_partial_stripes_expensive;
1437
1438 ret = bcache_device_init(&dc->disk, block_size,
1439 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
1440 dc->bdev, &bcache_cached_ops);
1441 if (ret)
1442 return ret;
1443
1444 blk_queue_io_opt(dc->disk.disk->queue,
1445 max(queue_io_opt(dc->disk.disk->queue), queue_io_opt(q)));
1446
1447 atomic_set(&dc->io_errors, 0);
1448 dc->io_disable = false;
1449 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1450 /* default to auto */
1451 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1452
1453 bch_cached_dev_request_init(dc);
1454 bch_cached_dev_writeback_init(dc);
1455 return 0;
1456 }
1457
1458 /* Cached device - bcache superblock */
1459
register_bdev(struct cache_sb * sb,struct cache_sb_disk * sb_disk,struct block_device * bdev,struct cached_dev * dc)1460 static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1461 struct block_device *bdev,
1462 struct cached_dev *dc)
1463 {
1464 const char *err = "cannot allocate memory";
1465 struct cache_set *c;
1466 int ret = -ENOMEM;
1467
1468 bdevname(bdev, dc->backing_dev_name);
1469 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1470 dc->bdev = bdev;
1471 dc->bdev->bd_holder = dc;
1472 dc->sb_disk = sb_disk;
1473
1474 if (cached_dev_init(dc, sb->block_size << 9))
1475 goto err;
1476
1477 err = "error creating kobject";
1478 if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache"))
1479 goto err;
1480 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1481 goto err;
1482
1483 pr_info("registered backing device %s\n", dc->backing_dev_name);
1484
1485 list_add(&dc->list, &uncached_devices);
1486 /* attach to a matched cache set if it exists */
1487 list_for_each_entry(c, &bch_cache_sets, list)
1488 bch_cached_dev_attach(dc, c, NULL);
1489
1490 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1491 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1492 err = "failed to run cached device";
1493 ret = bch_cached_dev_run(dc);
1494 if (ret)
1495 goto err;
1496 }
1497
1498 return 0;
1499 err:
1500 pr_notice("error %s: %s\n", dc->backing_dev_name, err);
1501 bcache_device_stop(&dc->disk);
1502 return ret;
1503 }
1504
1505 /* Flash only volumes */
1506
1507 /* When d->kobj released */
bch_flash_dev_release(struct kobject * kobj)1508 void bch_flash_dev_release(struct kobject *kobj)
1509 {
1510 struct bcache_device *d = container_of(kobj, struct bcache_device,
1511 kobj);
1512 kfree(d);
1513 }
1514
flash_dev_free(struct closure * cl)1515 static void flash_dev_free(struct closure *cl)
1516 {
1517 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1518
1519 mutex_lock(&bch_register_lock);
1520 atomic_long_sub(bcache_dev_sectors_dirty(d),
1521 &d->c->flash_dev_dirty_sectors);
1522 bcache_device_free(d);
1523 mutex_unlock(&bch_register_lock);
1524 kobject_put(&d->kobj);
1525 }
1526
flash_dev_flush(struct closure * cl)1527 static void flash_dev_flush(struct closure *cl)
1528 {
1529 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1530
1531 mutex_lock(&bch_register_lock);
1532 bcache_device_unlink(d);
1533 mutex_unlock(&bch_register_lock);
1534 kobject_del(&d->kobj);
1535 continue_at(cl, flash_dev_free, system_wq);
1536 }
1537
flash_dev_run(struct cache_set * c,struct uuid_entry * u)1538 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1539 {
1540 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1541 GFP_KERNEL);
1542 if (!d)
1543 return -ENOMEM;
1544
1545 closure_init(&d->cl, NULL);
1546 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1547
1548 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1549
1550 if (bcache_device_init(d, block_bytes(c->cache), u->sectors,
1551 NULL, &bcache_flash_ops))
1552 goto err;
1553
1554 bcache_device_attach(d, c, u - c->uuids);
1555 bch_sectors_dirty_init(d);
1556 bch_flash_dev_request_init(d);
1557 add_disk(d->disk);
1558
1559 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1560 goto err;
1561
1562 bcache_device_link(d, c, "volume");
1563
1564 if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
1565 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1566 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1567 set_disk_ro(d->disk, 1);
1568 }
1569
1570 return 0;
1571 err:
1572 kobject_put(&d->kobj);
1573 return -ENOMEM;
1574 }
1575
flash_devs_run(struct cache_set * c)1576 static int flash_devs_run(struct cache_set *c)
1577 {
1578 int ret = 0;
1579 struct uuid_entry *u;
1580
1581 for (u = c->uuids;
1582 u < c->uuids + c->nr_uuids && !ret;
1583 u++)
1584 if (UUID_FLASH_ONLY(u))
1585 ret = flash_dev_run(c, u);
1586
1587 return ret;
1588 }
1589
bch_flash_dev_create(struct cache_set * c,uint64_t size)1590 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1591 {
1592 struct uuid_entry *u;
1593
1594 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1595 return -EINTR;
1596
1597 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1598 return -EPERM;
1599
1600 u = uuid_find_empty(c);
1601 if (!u) {
1602 pr_err("Can't create volume, no room for UUID\n");
1603 return -EINVAL;
1604 }
1605
1606 get_random_bytes(u->uuid, 16);
1607 memset(u->label, 0, 32);
1608 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1609
1610 SET_UUID_FLASH_ONLY(u, 1);
1611 u->sectors = size >> 9;
1612
1613 bch_uuid_write(c);
1614
1615 return flash_dev_run(c, u);
1616 }
1617
bch_cached_dev_error(struct cached_dev * dc)1618 bool bch_cached_dev_error(struct cached_dev *dc)
1619 {
1620 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1621 return false;
1622
1623 dc->io_disable = true;
1624 /* make others know io_disable is true earlier */
1625 smp_mb();
1626
1627 pr_err("stop %s: too many IO errors on backing device %s\n",
1628 dc->disk.disk->disk_name, dc->backing_dev_name);
1629
1630 bcache_device_stop(&dc->disk);
1631 return true;
1632 }
1633
1634 /* Cache set */
1635
1636 __printf(2, 3)
bch_cache_set_error(struct cache_set * c,const char * fmt,...)1637 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1638 {
1639 struct va_format vaf;
1640 va_list args;
1641
1642 if (c->on_error != ON_ERROR_PANIC &&
1643 test_bit(CACHE_SET_STOPPING, &c->flags))
1644 return false;
1645
1646 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1647 pr_info("CACHE_SET_IO_DISABLE already set\n");
1648
1649 /*
1650 * XXX: we can be called from atomic context
1651 * acquire_console_sem();
1652 */
1653
1654 va_start(args, fmt);
1655
1656 vaf.fmt = fmt;
1657 vaf.va = &args;
1658
1659 pr_err("error on %pU: %pV, disabling caching\n",
1660 c->set_uuid, &vaf);
1661
1662 va_end(args);
1663
1664 if (c->on_error == ON_ERROR_PANIC)
1665 panic("panic forced after error\n");
1666
1667 bch_cache_set_unregister(c);
1668 return true;
1669 }
1670
1671 /* When c->kobj released */
bch_cache_set_release(struct kobject * kobj)1672 void bch_cache_set_release(struct kobject *kobj)
1673 {
1674 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1675
1676 kfree(c);
1677 module_put(THIS_MODULE);
1678 }
1679
cache_set_free(struct closure * cl)1680 static void cache_set_free(struct closure *cl)
1681 {
1682 struct cache_set *c = container_of(cl, struct cache_set, cl);
1683 struct cache *ca;
1684
1685 debugfs_remove(c->debug);
1686
1687 bch_open_buckets_free(c);
1688 bch_btree_cache_free(c);
1689 bch_journal_free(c);
1690
1691 mutex_lock(&bch_register_lock);
1692 bch_bset_sort_state_free(&c->sort);
1693 free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
1694
1695 ca = c->cache;
1696 if (ca) {
1697 ca->set = NULL;
1698 c->cache = NULL;
1699 kobject_put(&ca->kobj);
1700 }
1701
1702
1703 if (c->moving_gc_wq)
1704 destroy_workqueue(c->moving_gc_wq);
1705 bioset_exit(&c->bio_split);
1706 mempool_exit(&c->fill_iter);
1707 mempool_exit(&c->bio_meta);
1708 mempool_exit(&c->search);
1709 kfree(c->devices);
1710
1711 list_del(&c->list);
1712 mutex_unlock(&bch_register_lock);
1713
1714 pr_info("Cache set %pU unregistered\n", c->set_uuid);
1715 wake_up(&unregister_wait);
1716
1717 closure_debug_destroy(&c->cl);
1718 kobject_put(&c->kobj);
1719 }
1720
cache_set_flush(struct closure * cl)1721 static void cache_set_flush(struct closure *cl)
1722 {
1723 struct cache_set *c = container_of(cl, struct cache_set, caching);
1724 struct cache *ca = c->cache;
1725 struct btree *b;
1726
1727 bch_cache_accounting_destroy(&c->accounting);
1728
1729 kobject_put(&c->internal);
1730 kobject_del(&c->kobj);
1731
1732 if (!IS_ERR_OR_NULL(c->gc_thread))
1733 kthread_stop(c->gc_thread);
1734
1735 if (!IS_ERR_OR_NULL(c->root))
1736 list_add(&c->root->list, &c->btree_cache);
1737
1738 /*
1739 * Avoid flushing cached nodes if cache set is retiring
1740 * due to too many I/O errors detected.
1741 */
1742 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1743 list_for_each_entry(b, &c->btree_cache, list) {
1744 mutex_lock(&b->write_lock);
1745 if (btree_node_dirty(b))
1746 __bch_btree_node_write(b, NULL);
1747 mutex_unlock(&b->write_lock);
1748 }
1749
1750 if (ca->alloc_thread)
1751 kthread_stop(ca->alloc_thread);
1752
1753 if (c->journal.cur) {
1754 cancel_delayed_work_sync(&c->journal.work);
1755 /* flush last journal entry if needed */
1756 c->journal.work.work.func(&c->journal.work.work);
1757 }
1758
1759 closure_return(cl);
1760 }
1761
1762 /*
1763 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1764 * cache set is unregistering due to too many I/O errors. In this condition,
1765 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1766 * value and whether the broken cache has dirty data:
1767 *
1768 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1769 * BCH_CACHED_STOP_AUTO 0 NO
1770 * BCH_CACHED_STOP_AUTO 1 YES
1771 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1772 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1773 *
1774 * The expected behavior is, if stop_when_cache_set_failed is configured to
1775 * "auto" via sysfs interface, the bcache device will not be stopped if the
1776 * backing device is clean on the broken cache device.
1777 */
conditional_stop_bcache_device(struct cache_set * c,struct bcache_device * d,struct cached_dev * dc)1778 static void conditional_stop_bcache_device(struct cache_set *c,
1779 struct bcache_device *d,
1780 struct cached_dev *dc)
1781 {
1782 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1783 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1784 d->disk->disk_name, c->set_uuid);
1785 bcache_device_stop(d);
1786 } else if (atomic_read(&dc->has_dirty)) {
1787 /*
1788 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1789 * and dc->has_dirty == 1
1790 */
1791 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1792 d->disk->disk_name);
1793 /*
1794 * There might be a small time gap that cache set is
1795 * released but bcache device is not. Inside this time
1796 * gap, regular I/O requests will directly go into
1797 * backing device as no cache set attached to. This
1798 * behavior may also introduce potential inconsistence
1799 * data in writeback mode while cache is dirty.
1800 * Therefore before calling bcache_device_stop() due
1801 * to a broken cache device, dc->io_disable should be
1802 * explicitly set to true.
1803 */
1804 dc->io_disable = true;
1805 /* make others know io_disable is true earlier */
1806 smp_mb();
1807 bcache_device_stop(d);
1808 } else {
1809 /*
1810 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1811 * and dc->has_dirty == 0
1812 */
1813 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1814 d->disk->disk_name);
1815 }
1816 }
1817
__cache_set_unregister(struct closure * cl)1818 static void __cache_set_unregister(struct closure *cl)
1819 {
1820 struct cache_set *c = container_of(cl, struct cache_set, caching);
1821 struct cached_dev *dc;
1822 struct bcache_device *d;
1823 size_t i;
1824
1825 mutex_lock(&bch_register_lock);
1826
1827 for (i = 0; i < c->devices_max_used; i++) {
1828 d = c->devices[i];
1829 if (!d)
1830 continue;
1831
1832 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1833 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1834 dc = container_of(d, struct cached_dev, disk);
1835 bch_cached_dev_detach(dc);
1836 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1837 conditional_stop_bcache_device(c, d, dc);
1838 } else {
1839 bcache_device_stop(d);
1840 }
1841 }
1842
1843 mutex_unlock(&bch_register_lock);
1844
1845 continue_at(cl, cache_set_flush, system_wq);
1846 }
1847
bch_cache_set_stop(struct cache_set * c)1848 void bch_cache_set_stop(struct cache_set *c)
1849 {
1850 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1851 /* closure_fn set to __cache_set_unregister() */
1852 closure_queue(&c->caching);
1853 }
1854
bch_cache_set_unregister(struct cache_set * c)1855 void bch_cache_set_unregister(struct cache_set *c)
1856 {
1857 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1858 bch_cache_set_stop(c);
1859 }
1860
1861 #define alloc_meta_bucket_pages(gfp, sb) \
1862 ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1863
bch_cache_set_alloc(struct cache_sb * sb)1864 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1865 {
1866 int iter_size;
1867 struct cache *ca = container_of(sb, struct cache, sb);
1868 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1869
1870 if (!c)
1871 return NULL;
1872
1873 __module_get(THIS_MODULE);
1874 closure_init(&c->cl, NULL);
1875 set_closure_fn(&c->cl, cache_set_free, system_wq);
1876
1877 closure_init(&c->caching, &c->cl);
1878 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1879
1880 /* Maybe create continue_at_noreturn() and use it here? */
1881 closure_set_stopped(&c->cl);
1882 closure_put(&c->cl);
1883
1884 kobject_init(&c->kobj, &bch_cache_set_ktype);
1885 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1886
1887 bch_cache_accounting_init(&c->accounting, &c->cl);
1888
1889 memcpy(c->set_uuid, sb->set_uuid, 16);
1890
1891 c->cache = ca;
1892 c->cache->set = c;
1893 c->bucket_bits = ilog2(sb->bucket_size);
1894 c->block_bits = ilog2(sb->block_size);
1895 c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
1896 c->devices_max_used = 0;
1897 atomic_set(&c->attached_dev_nr, 0);
1898 c->btree_pages = meta_bucket_pages(sb);
1899 if (c->btree_pages > BTREE_MAX_PAGES)
1900 c->btree_pages = max_t(int, c->btree_pages / 4,
1901 BTREE_MAX_PAGES);
1902
1903 sema_init(&c->sb_write_mutex, 1);
1904 mutex_init(&c->bucket_lock);
1905 init_waitqueue_head(&c->btree_cache_wait);
1906 spin_lock_init(&c->btree_cannibalize_lock);
1907 init_waitqueue_head(&c->bucket_wait);
1908 init_waitqueue_head(&c->gc_wait);
1909 sema_init(&c->uuid_write_mutex, 1);
1910
1911 spin_lock_init(&c->btree_gc_time.lock);
1912 spin_lock_init(&c->btree_split_time.lock);
1913 spin_lock_init(&c->btree_read_time.lock);
1914
1915 bch_moving_init_cache_set(c);
1916
1917 INIT_LIST_HEAD(&c->list);
1918 INIT_LIST_HEAD(&c->cached_devs);
1919 INIT_LIST_HEAD(&c->btree_cache);
1920 INIT_LIST_HEAD(&c->btree_cache_freeable);
1921 INIT_LIST_HEAD(&c->btree_cache_freed);
1922 INIT_LIST_HEAD(&c->data_buckets);
1923
1924 iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
1925 sizeof(struct btree_iter_set);
1926
1927 c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1928 if (!c->devices)
1929 goto err;
1930
1931 if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1932 goto err;
1933
1934 if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1935 sizeof(struct bbio) +
1936 sizeof(struct bio_vec) * meta_bucket_pages(sb)))
1937 goto err;
1938
1939 if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1940 goto err;
1941
1942 if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1943 BIOSET_NEED_RESCUER))
1944 goto err;
1945
1946 c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
1947 if (!c->uuids)
1948 goto err;
1949
1950 c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
1951 if (!c->moving_gc_wq)
1952 goto err;
1953
1954 if (bch_journal_alloc(c))
1955 goto err;
1956
1957 if (bch_btree_cache_alloc(c))
1958 goto err;
1959
1960 if (bch_open_buckets_alloc(c))
1961 goto err;
1962
1963 if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1964 goto err;
1965
1966 c->congested_read_threshold_us = 2000;
1967 c->congested_write_threshold_us = 20000;
1968 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1969 c->idle_max_writeback_rate_enabled = 1;
1970 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1971
1972 return c;
1973 err:
1974 bch_cache_set_unregister(c);
1975 return NULL;
1976 }
1977
run_cache_set(struct cache_set * c)1978 static int run_cache_set(struct cache_set *c)
1979 {
1980 const char *err = "cannot allocate memory";
1981 struct cached_dev *dc, *t;
1982 struct cache *ca = c->cache;
1983 struct closure cl;
1984 LIST_HEAD(journal);
1985 struct journal_replay *l;
1986
1987 closure_init_stack(&cl);
1988
1989 c->nbuckets = ca->sb.nbuckets;
1990 set_gc_sectors(c);
1991
1992 if (CACHE_SYNC(&c->cache->sb)) {
1993 struct bkey *k;
1994 struct jset *j;
1995
1996 err = "cannot allocate memory for journal";
1997 if (bch_journal_read(c, &journal))
1998 goto err;
1999
2000 pr_debug("btree_journal_read() done\n");
2001
2002 err = "no journal entries found";
2003 if (list_empty(&journal))
2004 goto err;
2005
2006 j = &list_entry(journal.prev, struct journal_replay, list)->j;
2007
2008 err = "IO error reading priorities";
2009 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2010 goto err;
2011
2012 /*
2013 * If prio_read() fails it'll call cache_set_error and we'll
2014 * tear everything down right away, but if we perhaps checked
2015 * sooner we could avoid journal replay.
2016 */
2017
2018 k = &j->btree_root;
2019
2020 err = "bad btree root";
2021 if (__bch_btree_ptr_invalid(c, k))
2022 goto err;
2023
2024 err = "error reading btree root";
2025 c->root = bch_btree_node_get(c, NULL, k,
2026 j->btree_level,
2027 true, NULL);
2028 if (IS_ERR_OR_NULL(c->root))
2029 goto err;
2030
2031 list_del_init(&c->root->list);
2032 rw_unlock(true, c->root);
2033
2034 err = uuid_read(c, j, &cl);
2035 if (err)
2036 goto err;
2037
2038 err = "error in recovery";
2039 if (bch_btree_check(c))
2040 goto err;
2041
2042 bch_journal_mark(c, &journal);
2043 bch_initial_gc_finish(c);
2044 pr_debug("btree_check() done\n");
2045
2046 /*
2047 * bcache_journal_next() can't happen sooner, or
2048 * btree_gc_finish() will give spurious errors about last_gc >
2049 * gc_gen - this is a hack but oh well.
2050 */
2051 bch_journal_next(&c->journal);
2052
2053 err = "error starting allocator thread";
2054 if (bch_cache_allocator_start(ca))
2055 goto err;
2056
2057 /*
2058 * First place it's safe to allocate: btree_check() and
2059 * btree_gc_finish() have to run before we have buckets to
2060 * allocate, and bch_bucket_alloc_set() might cause a journal
2061 * entry to be written so bcache_journal_next() has to be called
2062 * first.
2063 *
2064 * If the uuids were in the old format we have to rewrite them
2065 * before the next journal entry is written:
2066 */
2067 if (j->version < BCACHE_JSET_VERSION_UUID)
2068 __uuid_write(c);
2069
2070 err = "bcache: replay journal failed";
2071 if (bch_journal_replay(c, &journal))
2072 goto err;
2073 } else {
2074 unsigned int j;
2075
2076 pr_notice("invalidating existing data\n");
2077 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2078 2, SB_JOURNAL_BUCKETS);
2079
2080 for (j = 0; j < ca->sb.keys; j++)
2081 ca->sb.d[j] = ca->sb.first_bucket + j;
2082
2083 bch_initial_gc_finish(c);
2084
2085 err = "error starting allocator thread";
2086 if (bch_cache_allocator_start(ca))
2087 goto err;
2088
2089 mutex_lock(&c->bucket_lock);
2090 bch_prio_write(ca, true);
2091 mutex_unlock(&c->bucket_lock);
2092
2093 err = "cannot allocate new UUID bucket";
2094 if (__uuid_write(c))
2095 goto err;
2096
2097 err = "cannot allocate new btree root";
2098 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2099 if (IS_ERR_OR_NULL(c->root))
2100 goto err;
2101
2102 mutex_lock(&c->root->write_lock);
2103 bkey_copy_key(&c->root->key, &MAX_KEY);
2104 bch_btree_node_write(c->root, &cl);
2105 mutex_unlock(&c->root->write_lock);
2106
2107 bch_btree_set_root(c->root);
2108 rw_unlock(true, c->root);
2109
2110 /*
2111 * We don't want to write the first journal entry until
2112 * everything is set up - fortunately journal entries won't be
2113 * written until the SET_CACHE_SYNC() here:
2114 */
2115 SET_CACHE_SYNC(&c->cache->sb, true);
2116
2117 bch_journal_next(&c->journal);
2118 bch_journal_meta(c, &cl);
2119 }
2120
2121 err = "error starting gc thread";
2122 if (bch_gc_thread_start(c))
2123 goto err;
2124
2125 closure_sync(&cl);
2126 c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
2127 bcache_write_super(c);
2128
2129 if (bch_has_feature_obso_large_bucket(&c->cache->sb))
2130 pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
2131
2132 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2133 bch_cached_dev_attach(dc, c, NULL);
2134
2135 flash_devs_run(c);
2136
2137 set_bit(CACHE_SET_RUNNING, &c->flags);
2138 return 0;
2139 err:
2140 while (!list_empty(&journal)) {
2141 l = list_first_entry(&journal, struct journal_replay, list);
2142 list_del(&l->list);
2143 kfree(l);
2144 }
2145
2146 closure_sync(&cl);
2147
2148 bch_cache_set_error(c, "%s", err);
2149
2150 return -EIO;
2151 }
2152
register_cache_set(struct cache * ca)2153 static const char *register_cache_set(struct cache *ca)
2154 {
2155 char buf[12];
2156 const char *err = "cannot allocate memory";
2157 struct cache_set *c;
2158
2159 list_for_each_entry(c, &bch_cache_sets, list)
2160 if (!memcmp(c->set_uuid, ca->sb.set_uuid, 16)) {
2161 if (c->cache)
2162 return "duplicate cache set member";
2163
2164 goto found;
2165 }
2166
2167 c = bch_cache_set_alloc(&ca->sb);
2168 if (!c)
2169 return err;
2170
2171 err = "error creating kobject";
2172 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->set_uuid) ||
2173 kobject_add(&c->internal, &c->kobj, "internal"))
2174 goto err;
2175
2176 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2177 goto err;
2178
2179 bch_debug_init_cache_set(c);
2180
2181 list_add(&c->list, &bch_cache_sets);
2182 found:
2183 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2184 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2185 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2186 goto err;
2187
2188 kobject_get(&ca->kobj);
2189 ca->set = c;
2190 ca->set->cache = ca;
2191
2192 err = "failed to run cache set";
2193 if (run_cache_set(c) < 0)
2194 goto err;
2195
2196 return NULL;
2197 err:
2198 bch_cache_set_unregister(c);
2199 return err;
2200 }
2201
2202 /* Cache device */
2203
2204 /* When ca->kobj released */
bch_cache_release(struct kobject * kobj)2205 void bch_cache_release(struct kobject *kobj)
2206 {
2207 struct cache *ca = container_of(kobj, struct cache, kobj);
2208 unsigned int i;
2209
2210 if (ca->set) {
2211 BUG_ON(ca->set->cache != ca);
2212 ca->set->cache = NULL;
2213 }
2214
2215 free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2216 kfree(ca->prio_buckets);
2217 vfree(ca->buckets);
2218
2219 free_heap(&ca->heap);
2220 free_fifo(&ca->free_inc);
2221
2222 for (i = 0; i < RESERVE_NR; i++)
2223 free_fifo(&ca->free[i]);
2224
2225 if (ca->sb_disk)
2226 put_page(virt_to_page(ca->sb_disk));
2227
2228 if (!IS_ERR_OR_NULL(ca->bdev))
2229 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2230
2231 kfree(ca);
2232 module_put(THIS_MODULE);
2233 }
2234
cache_alloc(struct cache * ca)2235 static int cache_alloc(struct cache *ca)
2236 {
2237 size_t free;
2238 size_t btree_buckets;
2239 struct bucket *b;
2240 int ret = -ENOMEM;
2241 const char *err = NULL;
2242
2243 __module_get(THIS_MODULE);
2244 kobject_init(&ca->kobj, &bch_cache_ktype);
2245
2246 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2247
2248 /*
2249 * when ca->sb.njournal_buckets is not zero, journal exists,
2250 * and in bch_journal_replay(), tree node may split,
2251 * so bucket of RESERVE_BTREE type is needed,
2252 * the worst situation is all journal buckets are valid journal,
2253 * and all the keys need to replay,
2254 * so the number of RESERVE_BTREE type buckets should be as much
2255 * as journal buckets
2256 */
2257 btree_buckets = ca->sb.njournal_buckets ?: 8;
2258 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2259 if (!free) {
2260 ret = -EPERM;
2261 err = "ca->sb.nbuckets is too small";
2262 goto err_free;
2263 }
2264
2265 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2266 GFP_KERNEL)) {
2267 err = "ca->free[RESERVE_BTREE] alloc failed";
2268 goto err_btree_alloc;
2269 }
2270
2271 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2272 GFP_KERNEL)) {
2273 err = "ca->free[RESERVE_PRIO] alloc failed";
2274 goto err_prio_alloc;
2275 }
2276
2277 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2278 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2279 goto err_movinggc_alloc;
2280 }
2281
2282 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2283 err = "ca->free[RESERVE_NONE] alloc failed";
2284 goto err_none_alloc;
2285 }
2286
2287 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2288 err = "ca->free_inc alloc failed";
2289 goto err_free_inc_alloc;
2290 }
2291
2292 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2293 err = "ca->heap alloc failed";
2294 goto err_heap_alloc;
2295 }
2296
2297 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2298 ca->sb.nbuckets));
2299 if (!ca->buckets) {
2300 err = "ca->buckets alloc failed";
2301 goto err_buckets_alloc;
2302 }
2303
2304 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2305 prio_buckets(ca), 2),
2306 GFP_KERNEL);
2307 if (!ca->prio_buckets) {
2308 err = "ca->prio_buckets alloc failed";
2309 goto err_prio_buckets_alloc;
2310 }
2311
2312 ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2313 if (!ca->disk_buckets) {
2314 err = "ca->disk_buckets alloc failed";
2315 goto err_disk_buckets_alloc;
2316 }
2317
2318 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2319
2320 for_each_bucket(b, ca)
2321 atomic_set(&b->pin, 0);
2322 return 0;
2323
2324 err_disk_buckets_alloc:
2325 kfree(ca->prio_buckets);
2326 err_prio_buckets_alloc:
2327 vfree(ca->buckets);
2328 err_buckets_alloc:
2329 free_heap(&ca->heap);
2330 err_heap_alloc:
2331 free_fifo(&ca->free_inc);
2332 err_free_inc_alloc:
2333 free_fifo(&ca->free[RESERVE_NONE]);
2334 err_none_alloc:
2335 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2336 err_movinggc_alloc:
2337 free_fifo(&ca->free[RESERVE_PRIO]);
2338 err_prio_alloc:
2339 free_fifo(&ca->free[RESERVE_BTREE]);
2340 err_btree_alloc:
2341 err_free:
2342 module_put(THIS_MODULE);
2343 if (err)
2344 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2345 return ret;
2346 }
2347
register_cache(struct cache_sb * sb,struct cache_sb_disk * sb_disk,struct block_device * bdev,struct cache * ca)2348 static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2349 struct block_device *bdev, struct cache *ca)
2350 {
2351 const char *err = NULL; /* must be set for any error case */
2352 int ret = 0;
2353
2354 bdevname(bdev, ca->cache_dev_name);
2355 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2356 ca->bdev = bdev;
2357 ca->bdev->bd_holder = ca;
2358 ca->sb_disk = sb_disk;
2359
2360 if (blk_queue_discard(bdev_get_queue(bdev)))
2361 ca->discard = CACHE_DISCARD(&ca->sb);
2362
2363 ret = cache_alloc(ca);
2364 if (ret != 0) {
2365 /*
2366 * If we failed here, it means ca->kobj is not initialized yet,
2367 * kobject_put() won't be called and there is no chance to
2368 * call blkdev_put() to bdev in bch_cache_release(). So we
2369 * explicitly call blkdev_put() here.
2370 */
2371 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2372 if (ret == -ENOMEM)
2373 err = "cache_alloc(): -ENOMEM";
2374 else if (ret == -EPERM)
2375 err = "cache_alloc(): cache device is too small";
2376 else
2377 err = "cache_alloc(): unknown error";
2378 goto err;
2379 }
2380
2381 if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) {
2382 err = "error calling kobject_add";
2383 ret = -ENOMEM;
2384 goto out;
2385 }
2386
2387 mutex_lock(&bch_register_lock);
2388 err = register_cache_set(ca);
2389 mutex_unlock(&bch_register_lock);
2390
2391 if (err) {
2392 ret = -ENODEV;
2393 goto out;
2394 }
2395
2396 pr_info("registered cache device %s\n", ca->cache_dev_name);
2397
2398 out:
2399 kobject_put(&ca->kobj);
2400
2401 err:
2402 if (err)
2403 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2404
2405 return ret;
2406 }
2407
2408 /* Global interfaces/init */
2409
2410 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2411 const char *buffer, size_t size);
2412 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2413 struct kobj_attribute *attr,
2414 const char *buffer, size_t size);
2415
2416 kobj_attribute_write(register, register_bcache);
2417 kobj_attribute_write(register_quiet, register_bcache);
2418 kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2419
bch_is_open_backing(dev_t dev)2420 static bool bch_is_open_backing(dev_t dev)
2421 {
2422 struct cache_set *c, *tc;
2423 struct cached_dev *dc, *t;
2424
2425 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2426 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2427 if (dc->bdev->bd_dev == dev)
2428 return true;
2429 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2430 if (dc->bdev->bd_dev == dev)
2431 return true;
2432 return false;
2433 }
2434
bch_is_open_cache(dev_t dev)2435 static bool bch_is_open_cache(dev_t dev)
2436 {
2437 struct cache_set *c, *tc;
2438
2439 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2440 struct cache *ca = c->cache;
2441
2442 if (ca->bdev->bd_dev == dev)
2443 return true;
2444 }
2445
2446 return false;
2447 }
2448
bch_is_open(dev_t dev)2449 static bool bch_is_open(dev_t dev)
2450 {
2451 return bch_is_open_cache(dev) || bch_is_open_backing(dev);
2452 }
2453
2454 struct async_reg_args {
2455 struct delayed_work reg_work;
2456 char *path;
2457 struct cache_sb *sb;
2458 struct cache_sb_disk *sb_disk;
2459 struct block_device *bdev;
2460 };
2461
register_bdev_worker(struct work_struct * work)2462 static void register_bdev_worker(struct work_struct *work)
2463 {
2464 int fail = false;
2465 struct async_reg_args *args =
2466 container_of(work, struct async_reg_args, reg_work.work);
2467 struct cached_dev *dc;
2468
2469 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2470 if (!dc) {
2471 fail = true;
2472 put_page(virt_to_page(args->sb_disk));
2473 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2474 goto out;
2475 }
2476
2477 mutex_lock(&bch_register_lock);
2478 if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
2479 fail = true;
2480 mutex_unlock(&bch_register_lock);
2481
2482 out:
2483 if (fail)
2484 pr_info("error %s: fail to register backing device\n",
2485 args->path);
2486 kfree(args->sb);
2487 kfree(args->path);
2488 kfree(args);
2489 module_put(THIS_MODULE);
2490 }
2491
register_cache_worker(struct work_struct * work)2492 static void register_cache_worker(struct work_struct *work)
2493 {
2494 int fail = false;
2495 struct async_reg_args *args =
2496 container_of(work, struct async_reg_args, reg_work.work);
2497 struct cache *ca;
2498
2499 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2500 if (!ca) {
2501 fail = true;
2502 put_page(virt_to_page(args->sb_disk));
2503 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2504 goto out;
2505 }
2506
2507 /* blkdev_put() will be called in bch_cache_release() */
2508 if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
2509 fail = true;
2510
2511 out:
2512 if (fail)
2513 pr_info("error %s: fail to register cache device\n",
2514 args->path);
2515 kfree(args->sb);
2516 kfree(args->path);
2517 kfree(args);
2518 module_put(THIS_MODULE);
2519 }
2520
register_device_async(struct async_reg_args * args)2521 static void register_device_async(struct async_reg_args *args)
2522 {
2523 if (SB_IS_BDEV(args->sb))
2524 INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2525 else
2526 INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2527
2528 /* 10 jiffies is enough for a delay */
2529 queue_delayed_work(system_wq, &args->reg_work, 10);
2530 }
2531
register_bcache(struct kobject * k,struct kobj_attribute * attr,const char * buffer,size_t size)2532 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2533 const char *buffer, size_t size)
2534 {
2535 const char *err;
2536 char *path = NULL;
2537 struct cache_sb *sb;
2538 struct cache_sb_disk *sb_disk;
2539 struct block_device *bdev;
2540 ssize_t ret;
2541 bool async_registration = false;
2542
2543 #ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2544 async_registration = true;
2545 #endif
2546
2547 ret = -EBUSY;
2548 err = "failed to reference bcache module";
2549 if (!try_module_get(THIS_MODULE))
2550 goto out;
2551
2552 /* For latest state of bcache_is_reboot */
2553 smp_mb();
2554 err = "bcache is in reboot";
2555 if (bcache_is_reboot)
2556 goto out_module_put;
2557
2558 ret = -ENOMEM;
2559 err = "cannot allocate memory";
2560 path = kstrndup(buffer, size, GFP_KERNEL);
2561 if (!path)
2562 goto out_module_put;
2563
2564 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2565 if (!sb)
2566 goto out_free_path;
2567
2568 ret = -EINVAL;
2569 err = "failed to open device";
2570 bdev = blkdev_get_by_path(strim(path),
2571 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2572 sb);
2573 if (IS_ERR(bdev)) {
2574 if (bdev == ERR_PTR(-EBUSY)) {
2575 dev_t dev;
2576
2577 mutex_lock(&bch_register_lock);
2578 if (lookup_bdev(strim(path), &dev) == 0 &&
2579 bch_is_open(dev))
2580 err = "device already registered";
2581 else
2582 err = "device busy";
2583 mutex_unlock(&bch_register_lock);
2584 if (attr == &ksysfs_register_quiet)
2585 goto done;
2586 }
2587 goto out_free_sb;
2588 }
2589
2590 err = "failed to set blocksize";
2591 if (set_blocksize(bdev, 4096))
2592 goto out_blkdev_put;
2593
2594 err = read_super(sb, bdev, &sb_disk);
2595 if (err)
2596 goto out_blkdev_put;
2597
2598 err = "failed to register device";
2599
2600 if (async_registration) {
2601 /* register in asynchronous way */
2602 struct async_reg_args *args =
2603 kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2604
2605 if (!args) {
2606 ret = -ENOMEM;
2607 err = "cannot allocate memory";
2608 goto out_put_sb_page;
2609 }
2610
2611 args->path = path;
2612 args->sb = sb;
2613 args->sb_disk = sb_disk;
2614 args->bdev = bdev;
2615 register_device_async(args);
2616 /* No wait and returns to user space */
2617 goto async_done;
2618 }
2619
2620 if (SB_IS_BDEV(sb)) {
2621 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2622
2623 if (!dc)
2624 goto out_put_sb_page;
2625
2626 mutex_lock(&bch_register_lock);
2627 ret = register_bdev(sb, sb_disk, bdev, dc);
2628 mutex_unlock(&bch_register_lock);
2629 /* blkdev_put() will be called in cached_dev_free() */
2630 if (ret < 0)
2631 goto out_free_sb;
2632 } else {
2633 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2634
2635 if (!ca)
2636 goto out_put_sb_page;
2637
2638 /* blkdev_put() will be called in bch_cache_release() */
2639 if (register_cache(sb, sb_disk, bdev, ca) != 0)
2640 goto out_free_sb;
2641 }
2642
2643 done:
2644 kfree(sb);
2645 kfree(path);
2646 module_put(THIS_MODULE);
2647 async_done:
2648 return size;
2649
2650 out_put_sb_page:
2651 put_page(virt_to_page(sb_disk));
2652 out_blkdev_put:
2653 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2654 out_free_sb:
2655 kfree(sb);
2656 out_free_path:
2657 kfree(path);
2658 path = NULL;
2659 out_module_put:
2660 module_put(THIS_MODULE);
2661 out:
2662 pr_info("error %s: %s\n", path?path:"", err);
2663 return ret;
2664 }
2665
2666
2667 struct pdev {
2668 struct list_head list;
2669 struct cached_dev *dc;
2670 };
2671
bch_pending_bdevs_cleanup(struct kobject * k,struct kobj_attribute * attr,const char * buffer,size_t size)2672 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2673 struct kobj_attribute *attr,
2674 const char *buffer,
2675 size_t size)
2676 {
2677 LIST_HEAD(pending_devs);
2678 ssize_t ret = size;
2679 struct cached_dev *dc, *tdc;
2680 struct pdev *pdev, *tpdev;
2681 struct cache_set *c, *tc;
2682
2683 mutex_lock(&bch_register_lock);
2684 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2685 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2686 if (!pdev)
2687 break;
2688 pdev->dc = dc;
2689 list_add(&pdev->list, &pending_devs);
2690 }
2691
2692 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2693 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2694 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2695 char *set_uuid = c->set_uuid;
2696
2697 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2698 list_del(&pdev->list);
2699 kfree(pdev);
2700 break;
2701 }
2702 }
2703 }
2704 mutex_unlock(&bch_register_lock);
2705
2706 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2707 pr_info("delete pdev %p\n", pdev);
2708 list_del(&pdev->list);
2709 bcache_device_stop(&pdev->dc->disk);
2710 kfree(pdev);
2711 }
2712
2713 return ret;
2714 }
2715
bcache_reboot(struct notifier_block * n,unsigned long code,void * x)2716 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2717 {
2718 if (bcache_is_reboot)
2719 return NOTIFY_DONE;
2720
2721 if (code == SYS_DOWN ||
2722 code == SYS_HALT ||
2723 code == SYS_POWER_OFF) {
2724 DEFINE_WAIT(wait);
2725 unsigned long start = jiffies;
2726 bool stopped = false;
2727
2728 struct cache_set *c, *tc;
2729 struct cached_dev *dc, *tdc;
2730
2731 mutex_lock(&bch_register_lock);
2732
2733 if (bcache_is_reboot)
2734 goto out;
2735
2736 /* New registration is rejected since now */
2737 bcache_is_reboot = true;
2738 /*
2739 * Make registering caller (if there is) on other CPU
2740 * core know bcache_is_reboot set to true earlier
2741 */
2742 smp_mb();
2743
2744 if (list_empty(&bch_cache_sets) &&
2745 list_empty(&uncached_devices))
2746 goto out;
2747
2748 mutex_unlock(&bch_register_lock);
2749
2750 pr_info("Stopping all devices:\n");
2751
2752 /*
2753 * The reason bch_register_lock is not held to call
2754 * bch_cache_set_stop() and bcache_device_stop() is to
2755 * avoid potential deadlock during reboot, because cache
2756 * set or bcache device stopping process will acqurie
2757 * bch_register_lock too.
2758 *
2759 * We are safe here because bcache_is_reboot sets to
2760 * true already, register_bcache() will reject new
2761 * registration now. bcache_is_reboot also makes sure
2762 * bcache_reboot() won't be re-entered on by other thread,
2763 * so there is no race in following list iteration by
2764 * list_for_each_entry_safe().
2765 */
2766 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2767 bch_cache_set_stop(c);
2768
2769 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2770 bcache_device_stop(&dc->disk);
2771
2772
2773 /*
2774 * Give an early chance for other kthreads and
2775 * kworkers to stop themselves
2776 */
2777 schedule();
2778
2779 /* What's a condition variable? */
2780 while (1) {
2781 long timeout = start + 10 * HZ - jiffies;
2782
2783 mutex_lock(&bch_register_lock);
2784 stopped = list_empty(&bch_cache_sets) &&
2785 list_empty(&uncached_devices);
2786
2787 if (timeout < 0 || stopped)
2788 break;
2789
2790 prepare_to_wait(&unregister_wait, &wait,
2791 TASK_UNINTERRUPTIBLE);
2792
2793 mutex_unlock(&bch_register_lock);
2794 schedule_timeout(timeout);
2795 }
2796
2797 finish_wait(&unregister_wait, &wait);
2798
2799 if (stopped)
2800 pr_info("All devices stopped\n");
2801 else
2802 pr_notice("Timeout waiting for devices to be closed\n");
2803 out:
2804 mutex_unlock(&bch_register_lock);
2805 }
2806
2807 return NOTIFY_DONE;
2808 }
2809
2810 static struct notifier_block reboot = {
2811 .notifier_call = bcache_reboot,
2812 .priority = INT_MAX, /* before any real devices */
2813 };
2814
bcache_exit(void)2815 static void bcache_exit(void)
2816 {
2817 bch_debug_exit();
2818 bch_request_exit();
2819 if (bcache_kobj)
2820 kobject_put(bcache_kobj);
2821 if (bcache_wq)
2822 destroy_workqueue(bcache_wq);
2823 if (bch_journal_wq)
2824 destroy_workqueue(bch_journal_wq);
2825 if (bch_flush_wq)
2826 destroy_workqueue(bch_flush_wq);
2827 bch_btree_exit();
2828
2829 if (bcache_major)
2830 unregister_blkdev(bcache_major, "bcache");
2831 unregister_reboot_notifier(&reboot);
2832 mutex_destroy(&bch_register_lock);
2833 }
2834
2835 /* Check and fixup module parameters */
check_module_parameters(void)2836 static void check_module_parameters(void)
2837 {
2838 if (bch_cutoff_writeback_sync == 0)
2839 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2840 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2841 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2842 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2843 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2844 }
2845
2846 if (bch_cutoff_writeback == 0)
2847 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2848 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2849 pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2850 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2851 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2852 }
2853
2854 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2855 pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2856 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2857 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2858 }
2859 }
2860
bcache_init(void)2861 static int __init bcache_init(void)
2862 {
2863 static const struct attribute *files[] = {
2864 &ksysfs_register.attr,
2865 &ksysfs_register_quiet.attr,
2866 &ksysfs_pendings_cleanup.attr,
2867 NULL
2868 };
2869
2870 check_module_parameters();
2871
2872 mutex_init(&bch_register_lock);
2873 init_waitqueue_head(&unregister_wait);
2874 register_reboot_notifier(&reboot);
2875
2876 bcache_major = register_blkdev(0, "bcache");
2877 if (bcache_major < 0) {
2878 unregister_reboot_notifier(&reboot);
2879 mutex_destroy(&bch_register_lock);
2880 return bcache_major;
2881 }
2882
2883 if (bch_btree_init())
2884 goto err;
2885
2886 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2887 if (!bcache_wq)
2888 goto err;
2889
2890 /*
2891 * Let's not make this `WQ_MEM_RECLAIM` for the following reasons:
2892 *
2893 * 1. It used `system_wq` before which also does no memory reclaim.
2894 * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and
2895 * reduced throughput can be observed.
2896 *
2897 * We still want to user our own queue to not congest the `system_wq`.
2898 */
2899 bch_flush_wq = alloc_workqueue("bch_flush", 0, 0);
2900 if (!bch_flush_wq)
2901 goto err;
2902
2903 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2904 if (!bch_journal_wq)
2905 goto err;
2906
2907 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2908 if (!bcache_kobj)
2909 goto err;
2910
2911 if (bch_request_init() ||
2912 sysfs_create_files(bcache_kobj, files))
2913 goto err;
2914
2915 bch_debug_init();
2916 closure_debug_init();
2917
2918 bcache_is_reboot = false;
2919
2920 return 0;
2921 err:
2922 bcache_exit();
2923 return -ENOMEM;
2924 }
2925
2926 /*
2927 * Module hooks
2928 */
2929 module_exit(bcache_exit);
2930 module_init(bcache_init);
2931
2932 module_param(bch_cutoff_writeback, uint, 0);
2933 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2934
2935 module_param(bch_cutoff_writeback_sync, uint, 0);
2936 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2937
2938 MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2939 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2940 MODULE_LICENSE("GPL");
2941