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gpio: rcar: Fix runtime PM imbalance on error
[linux/fpc-iii.git] / drivers / md / bcache / super.c
blobd98354fa28e3ea3aef890838b4d09cb28cccdd3c
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
17 #include <linux/blkdev.h>
18 #include <linux/debugfs.h>
19 #include <linux/genhd.h>
20 #include <linux/idr.h>
21 #include <linux/kthread.h>
22 #include <linux/module.h>
23 #include <linux/random.h>
24 #include <linux/reboot.h>
25 #include <linux/sysfs.h>
26
27 unsigned int bch_cutoff_writeback;
28 unsigned int bch_cutoff_writeback_sync;
29
30 static const char bcache_magic[] = {
31 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
32 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
33 };
34
35 static const char invalid_uuid[] = {
36 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
37 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
38 };
39
40 static struct kobject *bcache_kobj;
41 struct mutex bch_register_lock;
42 bool bcache_is_reboot;
43 LIST_HEAD(bch_cache_sets);
44 static LIST_HEAD(uncached_devices);
45
46 static int bcache_major;
47 static DEFINE_IDA(bcache_device_idx);
48 static wait_queue_head_t unregister_wait;
49 struct workqueue_struct *bcache_wq;
50 struct workqueue_struct *bch_journal_wq;
51
52
53 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
54 /* limitation of partitions number on single bcache device */
55 #define BCACHE_MINORS 128
56 /* limitation of bcache devices number on single system */
57 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
58
59 /* Superblock */
60
61 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
62 struct cache_sb_disk **res)
63 {
64 const char *err;
65 struct cache_sb_disk *s;
66 struct page *page;
67 unsigned int i;
68
69 page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
70 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
71 if (IS_ERR(page))
72 return "IO error";
73 s = page_address(page) + offset_in_page(SB_OFFSET);
74
75 sb->offset = le64_to_cpu(s->offset);
76 sb->version = le64_to_cpu(s->version);
77
78 memcpy(sb->magic, s->magic, 16);
79 memcpy(sb->uuid, s->uuid, 16);
80 memcpy(sb->set_uuid, s->set_uuid, 16);
81 memcpy(sb->label, s->label, SB_LABEL_SIZE);
82
83 sb->flags = le64_to_cpu(s->flags);
84 sb->seq = le64_to_cpu(s->seq);
85 sb->last_mount = le32_to_cpu(s->last_mount);
86 sb->first_bucket = le16_to_cpu(s->first_bucket);
87 sb->keys = le16_to_cpu(s->keys);
88
89 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
90 sb->d[i] = le64_to_cpu(s->d[i]);
91
92 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
93 sb->version, sb->flags, sb->seq, sb->keys);
94
95 err = "Not a bcache superblock (bad offset)";
96 if (sb->offset != SB_SECTOR)
97 goto err;
98
99 err = "Not a bcache superblock (bad magic)";
100 if (memcmp(sb->magic, bcache_magic, 16))
101 goto err;
102
103 err = "Too many journal buckets";
104 if (sb->keys > SB_JOURNAL_BUCKETS)
105 goto err;
106
107 err = "Bad checksum";
108 if (s->csum != csum_set(s))
109 goto err;
110
111 err = "Bad UUID";
112 if (bch_is_zero(sb->uuid, 16))
113 goto err;
114
115 sb->block_size = le16_to_cpu(s->block_size);
116
117 err = "Superblock block size smaller than device block size";
118 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
119 goto err;
120
121 switch (sb->version) {
122 case BCACHE_SB_VERSION_BDEV:
123 sb->data_offset = BDEV_DATA_START_DEFAULT;
124 break;
125 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
126 sb->data_offset = le64_to_cpu(s->data_offset);
127
128 err = "Bad data offset";
129 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
130 goto err;
131
132 break;
133 case BCACHE_SB_VERSION_CDEV:
134 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
135 sb->nbuckets = le64_to_cpu(s->nbuckets);
136 sb->bucket_size = le16_to_cpu(s->bucket_size);
137
138 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
139 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
140
141 err = "Too many buckets";
142 if (sb->nbuckets > LONG_MAX)
143 goto err;
144
145 err = "Not enough buckets";
146 if (sb->nbuckets < 1 << 7)
147 goto err;
148
149 err = "Bad block/bucket size";
150 if (!is_power_of_2(sb->block_size) ||
151 sb->block_size > PAGE_SECTORS ||
152 !is_power_of_2(sb->bucket_size) ||
153 sb->bucket_size < PAGE_SECTORS)
154 goto err;
155
156 err = "Invalid superblock: device too small";
157 if (get_capacity(bdev->bd_disk) <
158 sb->bucket_size * sb->nbuckets)
159 goto err;
160
161 err = "Bad UUID";
162 if (bch_is_zero(sb->set_uuid, 16))
163 goto err;
164
165 err = "Bad cache device number in set";
166 if (!sb->nr_in_set ||
167 sb->nr_in_set <= sb->nr_this_dev ||
168 sb->nr_in_set > MAX_CACHES_PER_SET)
169 goto err;
170
171 err = "Journal buckets not sequential";
172 for (i = 0; i < sb->keys; i++)
173 if (sb->d[i] != sb->first_bucket + i)
174 goto err;
175
176 err = "Too many journal buckets";
177 if (sb->first_bucket + sb->keys > sb->nbuckets)
178 goto err;
179
180 err = "Invalid superblock: first bucket comes before end of super";
181 if (sb->first_bucket * sb->bucket_size < 16)
182 goto err;
183
184 break;
185 default:
186 err = "Unsupported superblock version";
187 goto err;
188 }
189
190 sb->last_mount = (u32)ktime_get_real_seconds();
191 *res = s;
192 return NULL;
193 err:
194 put_page(page);
195 return err;
196 }
197
198 static void write_bdev_super_endio(struct bio *bio)
199 {
200 struct cached_dev *dc = bio->bi_private;
201
202 if (bio->bi_status)
203 bch_count_backing_io_errors(dc, bio);
204
205 closure_put(&dc->sb_write);
206 }
207
208 static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
209 struct bio *bio)
210 {
211 unsigned int i;
212
213 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
214 bio->bi_iter.bi_sector = SB_SECTOR;
215 __bio_add_page(bio, virt_to_page(out), SB_SIZE,
216 offset_in_page(out));
217
218 out->offset = cpu_to_le64(sb->offset);
219 out->version = cpu_to_le64(sb->version);
220
221 memcpy(out->uuid, sb->uuid, 16);
222 memcpy(out->set_uuid, sb->set_uuid, 16);
223 memcpy(out->label, sb->label, SB_LABEL_SIZE);
224
225 out->flags = cpu_to_le64(sb->flags);
226 out->seq = cpu_to_le64(sb->seq);
227
228 out->last_mount = cpu_to_le32(sb->last_mount);
229 out->first_bucket = cpu_to_le16(sb->first_bucket);
230 out->keys = cpu_to_le16(sb->keys);
231
232 for (i = 0; i < sb->keys; i++)
233 out->d[i] = cpu_to_le64(sb->d[i]);
234
235 out->csum = csum_set(out);
236
237 pr_debug("ver %llu, flags %llu, seq %llu",
238 sb->version, sb->flags, sb->seq);
239
240 submit_bio(bio);
241 }
242
243 static void bch_write_bdev_super_unlock(struct closure *cl)
244 {
245 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
246
247 up(&dc->sb_write_mutex);
248 }
249
250 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
251 {
252 struct closure *cl = &dc->sb_write;
253 struct bio *bio = &dc->sb_bio;
254
255 down(&dc->sb_write_mutex);
256 closure_init(cl, parent);
257
258 bio_init(bio, dc->sb_bv, 1);
259 bio_set_dev(bio, dc->bdev);
260 bio->bi_end_io = write_bdev_super_endio;
261 bio->bi_private = dc;
262
263 closure_get(cl);
264 /* I/O request sent to backing device */
265 __write_super(&dc->sb, dc->sb_disk, bio);
266
267 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
268 }
269
270 static void write_super_endio(struct bio *bio)
271 {
272 struct cache *ca = bio->bi_private;
273
274 /* is_read = 0 */
275 bch_count_io_errors(ca, bio->bi_status, 0,
276 "writing superblock");
277 closure_put(&ca->set->sb_write);
278 }
279
280 static void bcache_write_super_unlock(struct closure *cl)
281 {
282 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
283
284 up(&c->sb_write_mutex);
285 }
286
287 void bcache_write_super(struct cache_set *c)
288 {
289 struct closure *cl = &c->sb_write;
290 struct cache *ca;
291 unsigned int i;
292
293 down(&c->sb_write_mutex);
294 closure_init(cl, &c->cl);
295
296 c->sb.seq++;
297
298 for_each_cache(ca, c, i) {
299 struct bio *bio = &ca->sb_bio;
300
301 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
302 ca->sb.seq = c->sb.seq;
303 ca->sb.last_mount = c->sb.last_mount;
304
305 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
306
307 bio_init(bio, ca->sb_bv, 1);
308 bio_set_dev(bio, ca->bdev);
309 bio->bi_end_io = write_super_endio;
310 bio->bi_private = ca;
311
312 closure_get(cl);
313 __write_super(&ca->sb, ca->sb_disk, bio);
314 }
315
316 closure_return_with_destructor(cl, bcache_write_super_unlock);
317 }
318
319 /* UUID io */
320
321 static void uuid_endio(struct bio *bio)
322 {
323 struct closure *cl = bio->bi_private;
324 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
325
326 cache_set_err_on(bio->bi_status, c, "accessing uuids");
327 bch_bbio_free(bio, c);
328 closure_put(cl);
329 }
330
331 static void uuid_io_unlock(struct closure *cl)
332 {
333 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
334
335 up(&c->uuid_write_mutex);
336 }
337
338 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
339 struct bkey *k, struct closure *parent)
340 {
341 struct closure *cl = &c->uuid_write;
342 struct uuid_entry *u;
343 unsigned int i;
344 char buf[80];
345
346 BUG_ON(!parent);
347 down(&c->uuid_write_mutex);
348 closure_init(cl, parent);
349
350 for (i = 0; i < KEY_PTRS(k); i++) {
351 struct bio *bio = bch_bbio_alloc(c);
352
353 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
354 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
355
356 bio->bi_end_io = uuid_endio;
357 bio->bi_private = cl;
358 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
359 bch_bio_map(bio, c->uuids);
360
361 bch_submit_bbio(bio, c, k, i);
362
363 if (op != REQ_OP_WRITE)
364 break;
365 }
366
367 bch_extent_to_text(buf, sizeof(buf), k);
368 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf);
369
370 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
371 if (!bch_is_zero(u->uuid, 16))
372 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
373 u - c->uuids, u->uuid, u->label,
374 u->first_reg, u->last_reg, u->invalidated);
375
376 closure_return_with_destructor(cl, uuid_io_unlock);
377 }
378
379 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
380 {
381 struct bkey *k = &j->uuid_bucket;
382
383 if (__bch_btree_ptr_invalid(c, k))
384 return "bad uuid pointer";
385
386 bkey_copy(&c->uuid_bucket, k);
387 uuid_io(c, REQ_OP_READ, 0, k, cl);
388
389 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
390 struct uuid_entry_v0 *u0 = (void *) c->uuids;
391 struct uuid_entry *u1 = (void *) c->uuids;
392 int i;
393
394 closure_sync(cl);
395
396 /*
397 * Since the new uuid entry is bigger than the old, we have to
398 * convert starting at the highest memory address and work down
399 * in order to do it in place
400 */
401
402 for (i = c->nr_uuids - 1;
403 i >= 0;
404 --i) {
405 memcpy(u1[i].uuid, u0[i].uuid, 16);
406 memcpy(u1[i].label, u0[i].label, 32);
407
408 u1[i].first_reg = u0[i].first_reg;
409 u1[i].last_reg = u0[i].last_reg;
410 u1[i].invalidated = u0[i].invalidated;
411
412 u1[i].flags = 0;
413 u1[i].sectors = 0;
414 }
415 }
416
417 return NULL;
418 }
419
420 static int __uuid_write(struct cache_set *c)
421 {
422 BKEY_PADDED(key) k;
423 struct closure cl;
424 struct cache *ca;
425
426 closure_init_stack(&cl);
427 lockdep_assert_held(&bch_register_lock);
428
429 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
430 return 1;
431
432 SET_KEY_SIZE(&k.key, c->sb.bucket_size);
433 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
434 closure_sync(&cl);
435
436 /* Only one bucket used for uuid write */
437 ca = PTR_CACHE(c, &k.key, 0);
438 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
439
440 bkey_copy(&c->uuid_bucket, &k.key);
441 bkey_put(c, &k.key);
442 return 0;
443 }
444
445 int bch_uuid_write(struct cache_set *c)
446 {
447 int ret = __uuid_write(c);
448
449 if (!ret)
450 bch_journal_meta(c, NULL);
451
452 return ret;
453 }
454
455 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
456 {
457 struct uuid_entry *u;
458
459 for (u = c->uuids;
460 u < c->uuids + c->nr_uuids; u++)
461 if (!memcmp(u->uuid, uuid, 16))
462 return u;
463
464 return NULL;
465 }
466
467 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
468 {
469 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
470
471 return uuid_find(c, zero_uuid);
472 }
473
474 /*
475 * Bucket priorities/gens:
476 *
477 * For each bucket, we store on disk its
478 * 8 bit gen
479 * 16 bit priority
480 *
481 * See alloc.c for an explanation of the gen. The priority is used to implement
482 * lru (and in the future other) cache replacement policies; for most purposes
483 * it's just an opaque integer.
484 *
485 * The gens and the priorities don't have a whole lot to do with each other, and
486 * it's actually the gens that must be written out at specific times - it's no
487 * big deal if the priorities don't get written, if we lose them we just reuse
488 * buckets in suboptimal order.
489 *
490 * On disk they're stored in a packed array, and in as many buckets are required
491 * to fit them all. The buckets we use to store them form a list; the journal
492 * header points to the first bucket, the first bucket points to the second
493 * bucket, et cetera.
494 *
495 * This code is used by the allocation code; periodically (whenever it runs out
496 * of buckets to allocate from) the allocation code will invalidate some
497 * buckets, but it can't use those buckets until their new gens are safely on
498 * disk.
499 */
500
501 static void prio_endio(struct bio *bio)
502 {
503 struct cache *ca = bio->bi_private;
504
505 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
506 bch_bbio_free(bio, ca->set);
507 closure_put(&ca->prio);
508 }
509
510 static void prio_io(struct cache *ca, uint64_t bucket, int op,
511 unsigned long op_flags)
512 {
513 struct closure *cl = &ca->prio;
514 struct bio *bio = bch_bbio_alloc(ca->set);
515
516 closure_init_stack(cl);
517
518 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
519 bio_set_dev(bio, ca->bdev);
520 bio->bi_iter.bi_size = bucket_bytes(ca);
521
522 bio->bi_end_io = prio_endio;
523 bio->bi_private = ca;
524 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
525 bch_bio_map(bio, ca->disk_buckets);
526
527 closure_bio_submit(ca->set, bio, &ca->prio);
528 closure_sync(cl);
529 }
530
531 int bch_prio_write(struct cache *ca, bool wait)
532 {
533 int i;
534 struct bucket *b;
535 struct closure cl;
536
537 pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu",
538 fifo_used(&ca->free[RESERVE_PRIO]),
539 fifo_used(&ca->free[RESERVE_NONE]),
540 fifo_used(&ca->free_inc));
541
542 /*
543 * Pre-check if there are enough free buckets. In the non-blocking
544 * scenario it's better to fail early rather than starting to allocate
545 * buckets and do a cleanup later in case of failure.
546 */
547 if (!wait) {
548 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
549 fifo_used(&ca->free[RESERVE_NONE]);
550 if (prio_buckets(ca) > avail)
551 return -ENOMEM;
552 }
553
554 closure_init_stack(&cl);
555
556 lockdep_assert_held(&ca->set->bucket_lock);
557
558 ca->disk_buckets->seq++;
559
560 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
561 &ca->meta_sectors_written);
562
563 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
564 long bucket;
565 struct prio_set *p = ca->disk_buckets;
566 struct bucket_disk *d = p->data;
567 struct bucket_disk *end = d + prios_per_bucket(ca);
568
569 for (b = ca->buckets + i * prios_per_bucket(ca);
570 b < ca->buckets + ca->sb.nbuckets && d < end;
571 b++, d++) {
572 d->prio = cpu_to_le16(b->prio);
573 d->gen = b->gen;
574 }
575
576 p->next_bucket = ca->prio_buckets[i + 1];
577 p->magic = pset_magic(&ca->sb);
578 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
579
580 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
581 BUG_ON(bucket == -1);
582
583 mutex_unlock(&ca->set->bucket_lock);
584 prio_io(ca, bucket, REQ_OP_WRITE, 0);
585 mutex_lock(&ca->set->bucket_lock);
586
587 ca->prio_buckets[i] = bucket;
588 atomic_dec_bug(&ca->buckets[bucket].pin);
589 }
590
591 mutex_unlock(&ca->set->bucket_lock);
592
593 bch_journal_meta(ca->set, &cl);
594 closure_sync(&cl);
595
596 mutex_lock(&ca->set->bucket_lock);
597
598 /*
599 * Don't want the old priorities to get garbage collected until after we
600 * finish writing the new ones, and they're journalled
601 */
602 for (i = 0; i < prio_buckets(ca); i++) {
603 if (ca->prio_last_buckets[i])
604 __bch_bucket_free(ca,
605 &ca->buckets[ca->prio_last_buckets[i]]);
606
607 ca->prio_last_buckets[i] = ca->prio_buckets[i];
608 }
609 return 0;
610 }
611
612 static int prio_read(struct cache *ca, uint64_t bucket)
613 {
614 struct prio_set *p = ca->disk_buckets;
615 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
616 struct bucket *b;
617 unsigned int bucket_nr = 0;
618 int ret = -EIO;
619
620 for (b = ca->buckets;
621 b < ca->buckets + ca->sb.nbuckets;
622 b++, d++) {
623 if (d == end) {
624 ca->prio_buckets[bucket_nr] = bucket;
625 ca->prio_last_buckets[bucket_nr] = bucket;
626 bucket_nr++;
627
628 prio_io(ca, bucket, REQ_OP_READ, 0);
629
630 if (p->csum !=
631 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) {
632 pr_warn("bad csum reading priorities");
633 goto out;
634 }
635
636 if (p->magic != pset_magic(&ca->sb)) {
637 pr_warn("bad magic reading priorities");
638 goto out;
639 }
640
641 bucket = p->next_bucket;
642 d = p->data;
643 }
644
645 b->prio = le16_to_cpu(d->prio);
646 b->gen = b->last_gc = d->gen;
647 }
648
649 ret = 0;
650 out:
651 return ret;
652 }
653
654 /* Bcache device */
655
656 static int open_dev(struct block_device *b, fmode_t mode)
657 {
658 struct bcache_device *d = b->bd_disk->private_data;
659
660 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
661 return -ENXIO;
662
663 closure_get(&d->cl);
664 return 0;
665 }
666
667 static void release_dev(struct gendisk *b, fmode_t mode)
668 {
669 struct bcache_device *d = b->private_data;
670
671 closure_put(&d->cl);
672 }
673
674 static int ioctl_dev(struct block_device *b, fmode_t mode,
675 unsigned int cmd, unsigned long arg)
676 {
677 struct bcache_device *d = b->bd_disk->private_data;
678
679 return d->ioctl(d, mode, cmd, arg);
680 }
681
682 static const struct block_device_operations bcache_ops = {
683 .open = open_dev,
684 .release = release_dev,
685 .ioctl = ioctl_dev,
686 .owner = THIS_MODULE,
687 };
688
689 void bcache_device_stop(struct bcache_device *d)
690 {
691 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
692 /*
693 * closure_fn set to
694 * - cached device: cached_dev_flush()
695 * - flash dev: flash_dev_flush()
696 */
697 closure_queue(&d->cl);
698 }
699
700 static void bcache_device_unlink(struct bcache_device *d)
701 {
702 lockdep_assert_held(&bch_register_lock);
703
704 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
705 unsigned int i;
706 struct cache *ca;
707
708 sysfs_remove_link(&d->c->kobj, d->name);
709 sysfs_remove_link(&d->kobj, "cache");
710
711 for_each_cache(ca, d->c, i)
712 bd_unlink_disk_holder(ca->bdev, d->disk);
713 }
714 }
715
716 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
717 const char *name)
718 {
719 unsigned int i;
720 struct cache *ca;
721 int ret;
722
723 for_each_cache(ca, d->c, i)
724 bd_link_disk_holder(ca->bdev, d->disk);
725
726 snprintf(d->name, BCACHEDEVNAME_SIZE,
727 "%s%u", name, d->id);
728
729 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
730 if (ret < 0)
731 pr_err("Couldn't create device -> cache set symlink");
732
733 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
734 if (ret < 0)
735 pr_err("Couldn't create cache set -> device symlink");
736
737 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
738 }
739
740 static void bcache_device_detach(struct bcache_device *d)
741 {
742 lockdep_assert_held(&bch_register_lock);
743
744 atomic_dec(&d->c->attached_dev_nr);
745
746 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
747 struct uuid_entry *u = d->c->uuids + d->id;
748
749 SET_UUID_FLASH_ONLY(u, 0);
750 memcpy(u->uuid, invalid_uuid, 16);
751 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
752 bch_uuid_write(d->c);
753 }
754
755 bcache_device_unlink(d);
756
757 d->c->devices[d->id] = NULL;
758 closure_put(&d->c->caching);
759 d->c = NULL;
760 }
761
762 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
763 unsigned int id)
764 {
765 d->id = id;
766 d->c = c;
767 c->devices[id] = d;
768
769 if (id >= c->devices_max_used)
770 c->devices_max_used = id + 1;
771
772 closure_get(&c->caching);
773 }
774
775 static inline int first_minor_to_idx(int first_minor)
776 {
777 return (first_minor/BCACHE_MINORS);
778 }
779
780 static inline int idx_to_first_minor(int idx)
781 {
782 return (idx * BCACHE_MINORS);
783 }
784
785 static void bcache_device_free(struct bcache_device *d)
786 {
787 struct gendisk *disk = d->disk;
788
789 lockdep_assert_held(&bch_register_lock);
790
791 if (disk)
792 pr_info("%s stopped", disk->disk_name);
793 else
794 pr_err("bcache device (NULL gendisk) stopped");
795
796 if (d->c)
797 bcache_device_detach(d);
798
799 if (disk) {
800 if (disk->flags & GENHD_FL_UP)
801 del_gendisk(disk);
802
803 if (disk->queue)
804 blk_cleanup_queue(disk->queue);
805
806 ida_simple_remove(&bcache_device_idx,
807 first_minor_to_idx(disk->first_minor));
808 put_disk(disk);
809 }
810
811 bioset_exit(&d->bio_split);
812 kvfree(d->full_dirty_stripes);
813 kvfree(d->stripe_sectors_dirty);
814
815 closure_debug_destroy(&d->cl);
816 }
817
818 static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
819 sector_t sectors, make_request_fn make_request_fn)
820 {
821 struct request_queue *q;
822 const size_t max_stripes = min_t(size_t, INT_MAX,
823 SIZE_MAX / sizeof(atomic_t));
824 size_t n;
825 int idx;
826
827 if (!d->stripe_size)
828 d->stripe_size = 1 << 31;
829
830 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
831
832 if (!d->nr_stripes || d->nr_stripes > max_stripes) {
833 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)",
834 (unsigned int)d->nr_stripes);
835 return -ENOMEM;
836 }
837
838 n = d->nr_stripes * sizeof(atomic_t);
839 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
840 if (!d->stripe_sectors_dirty)
841 return -ENOMEM;
842
843 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
844 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
845 if (!d->full_dirty_stripes)
846 return -ENOMEM;
847
848 idx = ida_simple_get(&bcache_device_idx, 0,
849 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
850 if (idx < 0)
851 return idx;
852
853 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
854 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
855 goto err;
856
857 d->disk = alloc_disk(BCACHE_MINORS);
858 if (!d->disk)
859 goto err;
860
861 set_capacity(d->disk, sectors);
862 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
863
864 d->disk->major = bcache_major;
865 d->disk->first_minor = idx_to_first_minor(idx);
866 d->disk->fops = &bcache_ops;
867 d->disk->private_data = d;
868
869 q = blk_alloc_queue(make_request_fn, NUMA_NO_NODE);
870 if (!q)
871 return -ENOMEM;
872
873 d->disk->queue = q;
874 q->queuedata = d;
875 q->backing_dev_info->congested_data = d;
876 q->limits.max_hw_sectors = UINT_MAX;
877 q->limits.max_sectors = UINT_MAX;
878 q->limits.max_segment_size = UINT_MAX;
879 q->limits.max_segments = BIO_MAX_PAGES;
880 blk_queue_max_discard_sectors(q, UINT_MAX);
881 q->limits.discard_granularity = 512;
882 q->limits.io_min = block_size;
883 q->limits.logical_block_size = block_size;
884 q->limits.physical_block_size = block_size;
885 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
886 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
887 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
888
889 blk_queue_write_cache(q, true, true);
890
891 return 0;
892
893 err:
894 ida_simple_remove(&bcache_device_idx, idx);
895 return -ENOMEM;
896
897 }
898
899 /* Cached device */
900
901 static void calc_cached_dev_sectors(struct cache_set *c)
902 {
903 uint64_t sectors = 0;
904 struct cached_dev *dc;
905
906 list_for_each_entry(dc, &c->cached_devs, list)
907 sectors += bdev_sectors(dc->bdev);
908
909 c->cached_dev_sectors = sectors;
910 }
911
912 #define BACKING_DEV_OFFLINE_TIMEOUT 5
913 static int cached_dev_status_update(void *arg)
914 {
915 struct cached_dev *dc = arg;
916 struct request_queue *q;
917
918 /*
919 * If this delayed worker is stopping outside, directly quit here.
920 * dc->io_disable might be set via sysfs interface, so check it
921 * here too.
922 */
923 while (!kthread_should_stop() && !dc->io_disable) {
924 q = bdev_get_queue(dc->bdev);
925 if (blk_queue_dying(q))
926 dc->offline_seconds++;
927 else
928 dc->offline_seconds = 0;
929
930 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
931 pr_err("%s: device offline for %d seconds",
932 dc->backing_dev_name,
933 BACKING_DEV_OFFLINE_TIMEOUT);
934 pr_err("%s: disable I/O request due to backing "
935 "device offline", dc->disk.name);
936 dc->io_disable = true;
937 /* let others know earlier that io_disable is true */
938 smp_mb();
939 bcache_device_stop(&dc->disk);
940 break;
941 }
942 schedule_timeout_interruptible(HZ);
943 }
944
945 wait_for_kthread_stop();
946 return 0;
947 }
948
949
950 int bch_cached_dev_run(struct cached_dev *dc)
951 {
952 struct bcache_device *d = &dc->disk;
953 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
954 char *env[] = {
955 "DRIVER=bcache",
956 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
957 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
958 NULL,
959 };
960
961 if (dc->io_disable) {
962 pr_err("I/O disabled on cached dev %s",
963 dc->backing_dev_name);
964 kfree(env[1]);
965 kfree(env[2]);
966 kfree(buf);
967 return -EIO;
968 }
969
970 if (atomic_xchg(&dc->running, 1)) {
971 kfree(env[1]);
972 kfree(env[2]);
973 kfree(buf);
974 pr_info("cached dev %s is running already",
975 dc->backing_dev_name);
976 return -EBUSY;
977 }
978
979 if (!d->c &&
980 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
981 struct closure cl;
982
983 closure_init_stack(&cl);
984
985 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
986 bch_write_bdev_super(dc, &cl);
987 closure_sync(&cl);
988 }
989
990 add_disk(d->disk);
991 bd_link_disk_holder(dc->bdev, dc->disk.disk);
992 /*
993 * won't show up in the uevent file, use udevadm monitor -e instead
994 * only class / kset properties are persistent
995 */
996 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
997 kfree(env[1]);
998 kfree(env[2]);
999 kfree(buf);
1000
1001 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1002 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1003 &d->kobj, "bcache")) {
1004 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks");
1005 return -ENOMEM;
1006 }
1007
1008 dc->status_update_thread = kthread_run(cached_dev_status_update,
1009 dc, "bcache_status_update");
1010 if (IS_ERR(dc->status_update_thread)) {
1011 pr_warn("failed to create bcache_status_update kthread, "
1012 "continue to run without monitoring backing "
1013 "device status");
1014 }
1015
1016 return 0;
1017 }
1018
1019 /*
1020 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1021 * work dc->writeback_rate_update is running. Wait until the routine
1022 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1023 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1024 * seconds, give up waiting here and continue to cancel it too.
1025 */
1026 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1027 {
1028 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1029
1030 do {
1031 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1032 &dc->disk.flags))
1033 break;
1034 time_out--;
1035 schedule_timeout_interruptible(1);
1036 } while (time_out > 0);
1037
1038 if (time_out == 0)
1039 pr_warn("give up waiting for dc->writeback_write_update to quit");
1040
1041 cancel_delayed_work_sync(&dc->writeback_rate_update);
1042 }
1043
1044 static void cached_dev_detach_finish(struct work_struct *w)
1045 {
1046 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1047 struct closure cl;
1048
1049 closure_init_stack(&cl);
1050
1051 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1052 BUG_ON(refcount_read(&dc->count));
1053
1054
1055 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1056 cancel_writeback_rate_update_dwork(dc);
1057
1058 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1059 kthread_stop(dc->writeback_thread);
1060 dc->writeback_thread = NULL;
1061 }
1062
1063 memset(&dc->sb.set_uuid, 0, 16);
1064 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
1065
1066 bch_write_bdev_super(dc, &cl);
1067 closure_sync(&cl);
1068
1069 mutex_lock(&bch_register_lock);
1070
1071 calc_cached_dev_sectors(dc->disk.c);
1072 bcache_device_detach(&dc->disk);
1073 list_move(&dc->list, &uncached_devices);
1074
1075 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1076 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1077
1078 mutex_unlock(&bch_register_lock);
1079
1080 pr_info("Caching disabled for %s", dc->backing_dev_name);
1081
1082 /* Drop ref we took in cached_dev_detach() */
1083 closure_put(&dc->disk.cl);
1084 }
1085
1086 void bch_cached_dev_detach(struct cached_dev *dc)
1087 {
1088 lockdep_assert_held(&bch_register_lock);
1089
1090 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1091 return;
1092
1093 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1094 return;
1095
1096 /*
1097 * Block the device from being closed and freed until we're finished
1098 * detaching
1099 */
1100 closure_get(&dc->disk.cl);
1101
1102 bch_writeback_queue(dc);
1103
1104 cached_dev_put(dc);
1105 }
1106
1107 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1108 uint8_t *set_uuid)
1109 {
1110 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1111 struct uuid_entry *u;
1112 struct cached_dev *exist_dc, *t;
1113 int ret = 0;
1114
1115 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
1116 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
1117 return -ENOENT;
1118
1119 if (dc->disk.c) {
1120 pr_err("Can't attach %s: already attached",
1121 dc->backing_dev_name);
1122 return -EINVAL;
1123 }
1124
1125 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1126 pr_err("Can't attach %s: shutting down",
1127 dc->backing_dev_name);
1128 return -EINVAL;
1129 }
1130
1131 if (dc->sb.block_size < c->sb.block_size) {
1132 /* Will die */
1133 pr_err("Couldn't attach %s: block size less than set's block size",
1134 dc->backing_dev_name);
1135 return -EINVAL;
1136 }
1137
1138 /* Check whether already attached */
1139 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1140 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1141 pr_err("Tried to attach %s but duplicate UUID already attached",
1142 dc->backing_dev_name);
1143
1144 return -EINVAL;
1145 }
1146 }
1147
1148 u = uuid_find(c, dc->sb.uuid);
1149
1150 if (u &&
1151 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1152 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1153 memcpy(u->uuid, invalid_uuid, 16);
1154 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1155 u = NULL;
1156 }
1157
1158 if (!u) {
1159 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1160 pr_err("Couldn't find uuid for %s in set",
1161 dc->backing_dev_name);
1162 return -ENOENT;
1163 }
1164
1165 u = uuid_find_empty(c);
1166 if (!u) {
1167 pr_err("Not caching %s, no room for UUID",
1168 dc->backing_dev_name);
1169 return -EINVAL;
1170 }
1171 }
1172
1173 /*
1174 * Deadlocks since we're called via sysfs...
1175 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1176 */
1177
1178 if (bch_is_zero(u->uuid, 16)) {
1179 struct closure cl;
1180
1181 closure_init_stack(&cl);
1182
1183 memcpy(u->uuid, dc->sb.uuid, 16);
1184 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1185 u->first_reg = u->last_reg = rtime;
1186 bch_uuid_write(c);
1187
1188 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
1189 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1190
1191 bch_write_bdev_super(dc, &cl);
1192 closure_sync(&cl);
1193 } else {
1194 u->last_reg = rtime;
1195 bch_uuid_write(c);
1196 }
1197
1198 bcache_device_attach(&dc->disk, c, u - c->uuids);
1199 list_move(&dc->list, &c->cached_devs);
1200 calc_cached_dev_sectors(c);
1201
1202 /*
1203 * dc->c must be set before dc->count != 0 - paired with the mb in
1204 * cached_dev_get()
1205 */
1206 smp_wmb();
1207 refcount_set(&dc->count, 1);
1208
1209 /* Block writeback thread, but spawn it */
1210 down_write(&dc->writeback_lock);
1211 if (bch_cached_dev_writeback_start(dc)) {
1212 up_write(&dc->writeback_lock);
1213 pr_err("Couldn't start writeback facilities for %s",
1214 dc->disk.disk->disk_name);
1215 return -ENOMEM;
1216 }
1217
1218 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1219 atomic_set(&dc->has_dirty, 1);
1220 bch_writeback_queue(dc);
1221 }
1222
1223 bch_sectors_dirty_init(&dc->disk);
1224
1225 ret = bch_cached_dev_run(dc);
1226 if (ret && (ret != -EBUSY)) {
1227 up_write(&dc->writeback_lock);
1228 /*
1229 * bch_register_lock is held, bcache_device_stop() is not
1230 * able to be directly called. The kthread and kworker
1231 * created previously in bch_cached_dev_writeback_start()
1232 * have to be stopped manually here.
1233 */
1234 kthread_stop(dc->writeback_thread);
1235 cancel_writeback_rate_update_dwork(dc);
1236 pr_err("Couldn't run cached device %s",
1237 dc->backing_dev_name);
1238 return ret;
1239 }
1240
1241 bcache_device_link(&dc->disk, c, "bdev");
1242 atomic_inc(&c->attached_dev_nr);
1243
1244 /* Allow the writeback thread to proceed */
1245 up_write(&dc->writeback_lock);
1246
1247 pr_info("Caching %s as %s on set %pU",
1248 dc->backing_dev_name,
1249 dc->disk.disk->disk_name,
1250 dc->disk.c->sb.set_uuid);
1251 return 0;
1252 }
1253
1254 /* when dc->disk.kobj released */
1255 void bch_cached_dev_release(struct kobject *kobj)
1256 {
1257 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1258 disk.kobj);
1259 kfree(dc);
1260 module_put(THIS_MODULE);
1261 }
1262
1263 static void cached_dev_free(struct closure *cl)
1264 {
1265 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1266
1267 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1268 cancel_writeback_rate_update_dwork(dc);
1269
1270 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1271 kthread_stop(dc->writeback_thread);
1272 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1273 kthread_stop(dc->status_update_thread);
1274
1275 mutex_lock(&bch_register_lock);
1276
1277 if (atomic_read(&dc->running))
1278 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1279 bcache_device_free(&dc->disk);
1280 list_del(&dc->list);
1281
1282 mutex_unlock(&bch_register_lock);
1283
1284 if (dc->sb_disk)
1285 put_page(virt_to_page(dc->sb_disk));
1286
1287 if (!IS_ERR_OR_NULL(dc->bdev))
1288 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1289
1290 wake_up(&unregister_wait);
1291
1292 kobject_put(&dc->disk.kobj);
1293 }
1294
1295 static void cached_dev_flush(struct closure *cl)
1296 {
1297 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1298 struct bcache_device *d = &dc->disk;
1299
1300 mutex_lock(&bch_register_lock);
1301 bcache_device_unlink(d);
1302 mutex_unlock(&bch_register_lock);
1303
1304 bch_cache_accounting_destroy(&dc->accounting);
1305 kobject_del(&d->kobj);
1306
1307 continue_at(cl, cached_dev_free, system_wq);
1308 }
1309
1310 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1311 {
1312 int ret;
1313 struct io *io;
1314 struct request_queue *q = bdev_get_queue(dc->bdev);
1315
1316 __module_get(THIS_MODULE);
1317 INIT_LIST_HEAD(&dc->list);
1318 closure_init(&dc->disk.cl, NULL);
1319 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1320 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1321 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1322 sema_init(&dc->sb_write_mutex, 1);
1323 INIT_LIST_HEAD(&dc->io_lru);
1324 spin_lock_init(&dc->io_lock);
1325 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1326
1327 dc->sequential_cutoff = 4 << 20;
1328
1329 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1330 list_add(&io->lru, &dc->io_lru);
1331 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1332 }
1333
1334 dc->disk.stripe_size = q->limits.io_opt >> 9;
1335
1336 if (dc->disk.stripe_size)
1337 dc->partial_stripes_expensive =
1338 q->limits.raid_partial_stripes_expensive;
1339
1340 ret = bcache_device_init(&dc->disk, block_size,
1341 dc->bdev->bd_part->nr_sects - dc->sb.data_offset,
1342 cached_dev_make_request);
1343 if (ret)
1344 return ret;
1345
1346 dc->disk.disk->queue->backing_dev_info->ra_pages =
1347 max(dc->disk.disk->queue->backing_dev_info->ra_pages,
1348 q->backing_dev_info->ra_pages);
1349
1350 atomic_set(&dc->io_errors, 0);
1351 dc->io_disable = false;
1352 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1353 /* default to auto */
1354 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1355
1356 bch_cached_dev_request_init(dc);
1357 bch_cached_dev_writeback_init(dc);
1358 return 0;
1359 }
1360
1361 /* Cached device - bcache superblock */
1362
1363 static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1364 struct block_device *bdev,
1365 struct cached_dev *dc)
1366 {
1367 const char *err = "cannot allocate memory";
1368 struct cache_set *c;
1369 int ret = -ENOMEM;
1370
1371 bdevname(bdev, dc->backing_dev_name);
1372 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1373 dc->bdev = bdev;
1374 dc->bdev->bd_holder = dc;
1375 dc->sb_disk = sb_disk;
1376
1377 if (cached_dev_init(dc, sb->block_size << 9))
1378 goto err;
1379
1380 err = "error creating kobject";
1381 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1382 "bcache"))
1383 goto err;
1384 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1385 goto err;
1386
1387 pr_info("registered backing device %s", dc->backing_dev_name);
1388
1389 list_add(&dc->list, &uncached_devices);
1390 /* attach to a matched cache set if it exists */
1391 list_for_each_entry(c, &bch_cache_sets, list)
1392 bch_cached_dev_attach(dc, c, NULL);
1393
1394 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1395 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1396 err = "failed to run cached device";
1397 ret = bch_cached_dev_run(dc);
1398 if (ret)
1399 goto err;
1400 }
1401
1402 return 0;
1403 err:
1404 pr_notice("error %s: %s", dc->backing_dev_name, err);
1405 bcache_device_stop(&dc->disk);
1406 return ret;
1407 }
1408
1409 /* Flash only volumes */
1410
1411 /* When d->kobj released */
1412 void bch_flash_dev_release(struct kobject *kobj)
1413 {
1414 struct bcache_device *d = container_of(kobj, struct bcache_device,
1415 kobj);
1416 kfree(d);
1417 }
1418
1419 static void flash_dev_free(struct closure *cl)
1420 {
1421 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1422
1423 mutex_lock(&bch_register_lock);
1424 atomic_long_sub(bcache_dev_sectors_dirty(d),
1425 &d->c->flash_dev_dirty_sectors);
1426 bcache_device_free(d);
1427 mutex_unlock(&bch_register_lock);
1428 kobject_put(&d->kobj);
1429 }
1430
1431 static void flash_dev_flush(struct closure *cl)
1432 {
1433 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1434
1435 mutex_lock(&bch_register_lock);
1436 bcache_device_unlink(d);
1437 mutex_unlock(&bch_register_lock);
1438 kobject_del(&d->kobj);
1439 continue_at(cl, flash_dev_free, system_wq);
1440 }
1441
1442 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1443 {
1444 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1445 GFP_KERNEL);
1446 if (!d)
1447 return -ENOMEM;
1448
1449 closure_init(&d->cl, NULL);
1450 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1451
1452 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1453
1454 if (bcache_device_init(d, block_bytes(c), u->sectors,
1455 flash_dev_make_request))
1456 goto err;
1457
1458 bcache_device_attach(d, c, u - c->uuids);
1459 bch_sectors_dirty_init(d);
1460 bch_flash_dev_request_init(d);
1461 add_disk(d->disk);
1462
1463 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1464 goto err;
1465
1466 bcache_device_link(d, c, "volume");
1467
1468 return 0;
1469 err:
1470 kobject_put(&d->kobj);
1471 return -ENOMEM;
1472 }
1473
1474 static int flash_devs_run(struct cache_set *c)
1475 {
1476 int ret = 0;
1477 struct uuid_entry *u;
1478
1479 for (u = c->uuids;
1480 u < c->uuids + c->nr_uuids && !ret;
1481 u++)
1482 if (UUID_FLASH_ONLY(u))
1483 ret = flash_dev_run(c, u);
1484
1485 return ret;
1486 }
1487
1488 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1489 {
1490 struct uuid_entry *u;
1491
1492 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1493 return -EINTR;
1494
1495 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1496 return -EPERM;
1497
1498 u = uuid_find_empty(c);
1499 if (!u) {
1500 pr_err("Can't create volume, no room for UUID");
1501 return -EINVAL;
1502 }
1503
1504 get_random_bytes(u->uuid, 16);
1505 memset(u->label, 0, 32);
1506 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1507
1508 SET_UUID_FLASH_ONLY(u, 1);
1509 u->sectors = size >> 9;
1510
1511 bch_uuid_write(c);
1512
1513 return flash_dev_run(c, u);
1514 }
1515
1516 bool bch_cached_dev_error(struct cached_dev *dc)
1517 {
1518 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1519 return false;
1520
1521 dc->io_disable = true;
1522 /* make others know io_disable is true earlier */
1523 smp_mb();
1524
1525 pr_err("stop %s: too many IO errors on backing device %s\n",
1526 dc->disk.disk->disk_name, dc->backing_dev_name);
1527
1528 bcache_device_stop(&dc->disk);
1529 return true;
1530 }
1531
1532 /* Cache set */
1533
1534 __printf(2, 3)
1535 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1536 {
1537 va_list args;
1538
1539 if (c->on_error != ON_ERROR_PANIC &&
1540 test_bit(CACHE_SET_STOPPING, &c->flags))
1541 return false;
1542
1543 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1544 pr_info("CACHE_SET_IO_DISABLE already set");
1545
1546 /*
1547 * XXX: we can be called from atomic context
1548 * acquire_console_sem();
1549 */
1550
1551 pr_err("bcache: error on %pU: ", c->sb.set_uuid);
1552
1553 va_start(args, fmt);
1554 vprintk(fmt, args);
1555 va_end(args);
1556
1557 pr_err(", disabling caching\n");
1558
1559 if (c->on_error == ON_ERROR_PANIC)
1560 panic("panic forced after error\n");
1561
1562 bch_cache_set_unregister(c);
1563 return true;
1564 }
1565
1566 /* When c->kobj released */
1567 void bch_cache_set_release(struct kobject *kobj)
1568 {
1569 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1570
1571 kfree(c);
1572 module_put(THIS_MODULE);
1573 }
1574
1575 static void cache_set_free(struct closure *cl)
1576 {
1577 struct cache_set *c = container_of(cl, struct cache_set, cl);
1578 struct cache *ca;
1579 unsigned int i;
1580
1581 debugfs_remove(c->debug);
1582
1583 bch_open_buckets_free(c);
1584 bch_btree_cache_free(c);
1585 bch_journal_free(c);
1586
1587 mutex_lock(&bch_register_lock);
1588 for_each_cache(ca, c, i)
1589 if (ca) {
1590 ca->set = NULL;
1591 c->cache[ca->sb.nr_this_dev] = NULL;
1592 kobject_put(&ca->kobj);
1593 }
1594
1595 bch_bset_sort_state_free(&c->sort);
1596 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
1597
1598 if (c->moving_gc_wq)
1599 destroy_workqueue(c->moving_gc_wq);
1600 bioset_exit(&c->bio_split);
1601 mempool_exit(&c->fill_iter);
1602 mempool_exit(&c->bio_meta);
1603 mempool_exit(&c->search);
1604 kfree(c->devices);
1605
1606 list_del(&c->list);
1607 mutex_unlock(&bch_register_lock);
1608
1609 pr_info("Cache set %pU unregistered", c->sb.set_uuid);
1610 wake_up(&unregister_wait);
1611
1612 closure_debug_destroy(&c->cl);
1613 kobject_put(&c->kobj);
1614 }
1615
1616 static void cache_set_flush(struct closure *cl)
1617 {
1618 struct cache_set *c = container_of(cl, struct cache_set, caching);
1619 struct cache *ca;
1620 struct btree *b;
1621 unsigned int i;
1622
1623 bch_cache_accounting_destroy(&c->accounting);
1624
1625 kobject_put(&c->internal);
1626 kobject_del(&c->kobj);
1627
1628 if (!IS_ERR_OR_NULL(c->gc_thread))
1629 kthread_stop(c->gc_thread);
1630
1631 if (!IS_ERR_OR_NULL(c->root))
1632 list_add(&c->root->list, &c->btree_cache);
1633
1634 /*
1635 * Avoid flushing cached nodes if cache set is retiring
1636 * due to too many I/O errors detected.
1637 */
1638 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1639 list_for_each_entry(b, &c->btree_cache, list) {
1640 mutex_lock(&b->write_lock);
1641 if (btree_node_dirty(b))
1642 __bch_btree_node_write(b, NULL);
1643 mutex_unlock(&b->write_lock);
1644 }
1645
1646 for_each_cache(ca, c, i)
1647 if (ca->alloc_thread)
1648 kthread_stop(ca->alloc_thread);
1649
1650 if (c->journal.cur) {
1651 cancel_delayed_work_sync(&c->journal.work);
1652 /* flush last journal entry if needed */
1653 c->journal.work.work.func(&c->journal.work.work);
1654 }
1655
1656 closure_return(cl);
1657 }
1658
1659 /*
1660 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1661 * cache set is unregistering due to too many I/O errors. In this condition,
1662 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1663 * value and whether the broken cache has dirty data:
1664 *
1665 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1666 * BCH_CACHED_STOP_AUTO 0 NO
1667 * BCH_CACHED_STOP_AUTO 1 YES
1668 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1669 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1670 *
1671 * The expected behavior is, if stop_when_cache_set_failed is configured to
1672 * "auto" via sysfs interface, the bcache device will not be stopped if the
1673 * backing device is clean on the broken cache device.
1674 */
1675 static void conditional_stop_bcache_device(struct cache_set *c,
1676 struct bcache_device *d,
1677 struct cached_dev *dc)
1678 {
1679 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1680 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.",
1681 d->disk->disk_name, c->sb.set_uuid);
1682 bcache_device_stop(d);
1683 } else if (atomic_read(&dc->has_dirty)) {
1684 /*
1685 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1686 * and dc->has_dirty == 1
1687 */
1688 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.",
1689 d->disk->disk_name);
1690 /*
1691 * There might be a small time gap that cache set is
1692 * released but bcache device is not. Inside this time
1693 * gap, regular I/O requests will directly go into
1694 * backing device as no cache set attached to. This
1695 * behavior may also introduce potential inconsistence
1696 * data in writeback mode while cache is dirty.
1697 * Therefore before calling bcache_device_stop() due
1698 * to a broken cache device, dc->io_disable should be
1699 * explicitly set to true.
1700 */
1701 dc->io_disable = true;
1702 /* make others know io_disable is true earlier */
1703 smp_mb();
1704 bcache_device_stop(d);
1705 } else {
1706 /*
1707 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1708 * and dc->has_dirty == 0
1709 */
1710 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.",
1711 d->disk->disk_name);
1712 }
1713 }
1714
1715 static void __cache_set_unregister(struct closure *cl)
1716 {
1717 struct cache_set *c = container_of(cl, struct cache_set, caching);
1718 struct cached_dev *dc;
1719 struct bcache_device *d;
1720 size_t i;
1721
1722 mutex_lock(&bch_register_lock);
1723
1724 for (i = 0; i < c->devices_max_used; i++) {
1725 d = c->devices[i];
1726 if (!d)
1727 continue;
1728
1729 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1730 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1731 dc = container_of(d, struct cached_dev, disk);
1732 bch_cached_dev_detach(dc);
1733 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1734 conditional_stop_bcache_device(c, d, dc);
1735 } else {
1736 bcache_device_stop(d);
1737 }
1738 }
1739
1740 mutex_unlock(&bch_register_lock);
1741
1742 continue_at(cl, cache_set_flush, system_wq);
1743 }
1744
1745 void bch_cache_set_stop(struct cache_set *c)
1746 {
1747 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1748 /* closure_fn set to __cache_set_unregister() */
1749 closure_queue(&c->caching);
1750 }
1751
1752 void bch_cache_set_unregister(struct cache_set *c)
1753 {
1754 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1755 bch_cache_set_stop(c);
1756 }
1757
1758 #define alloc_bucket_pages(gfp, c) \
1759 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
1760
1761 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1762 {
1763 int iter_size;
1764 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1765
1766 if (!c)
1767 return NULL;
1768
1769 __module_get(THIS_MODULE);
1770 closure_init(&c->cl, NULL);
1771 set_closure_fn(&c->cl, cache_set_free, system_wq);
1772
1773 closure_init(&c->caching, &c->cl);
1774 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1775
1776 /* Maybe create continue_at_noreturn() and use it here? */
1777 closure_set_stopped(&c->cl);
1778 closure_put(&c->cl);
1779
1780 kobject_init(&c->kobj, &bch_cache_set_ktype);
1781 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1782
1783 bch_cache_accounting_init(&c->accounting, &c->cl);
1784
1785 memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1786 c->sb.block_size = sb->block_size;
1787 c->sb.bucket_size = sb->bucket_size;
1788 c->sb.nr_in_set = sb->nr_in_set;
1789 c->sb.last_mount = sb->last_mount;
1790 c->bucket_bits = ilog2(sb->bucket_size);
1791 c->block_bits = ilog2(sb->block_size);
1792 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
1793 c->devices_max_used = 0;
1794 atomic_set(&c->attached_dev_nr, 0);
1795 c->btree_pages = bucket_pages(c);
1796 if (c->btree_pages > BTREE_MAX_PAGES)
1797 c->btree_pages = max_t(int, c->btree_pages / 4,
1798 BTREE_MAX_PAGES);
1799
1800 sema_init(&c->sb_write_mutex, 1);
1801 mutex_init(&c->bucket_lock);
1802 init_waitqueue_head(&c->btree_cache_wait);
1803 spin_lock_init(&c->btree_cannibalize_lock);
1804 init_waitqueue_head(&c->bucket_wait);
1805 init_waitqueue_head(&c->gc_wait);
1806 sema_init(&c->uuid_write_mutex, 1);
1807
1808 spin_lock_init(&c->btree_gc_time.lock);
1809 spin_lock_init(&c->btree_split_time.lock);
1810 spin_lock_init(&c->btree_read_time.lock);
1811
1812 bch_moving_init_cache_set(c);
1813
1814 INIT_LIST_HEAD(&c->list);
1815 INIT_LIST_HEAD(&c->cached_devs);
1816 INIT_LIST_HEAD(&c->btree_cache);
1817 INIT_LIST_HEAD(&c->btree_cache_freeable);
1818 INIT_LIST_HEAD(&c->btree_cache_freed);
1819 INIT_LIST_HEAD(&c->data_buckets);
1820
1821 iter_size = (sb->bucket_size / sb->block_size + 1) *
1822 sizeof(struct btree_iter_set);
1823
1824 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) ||
1825 mempool_init_slab_pool(&c->search, 32, bch_search_cache) ||
1826 mempool_init_kmalloc_pool(&c->bio_meta, 2,
1827 sizeof(struct bbio) + sizeof(struct bio_vec) *
1828 bucket_pages(c)) ||
1829 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
1830 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1831 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) ||
1832 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
1833 !(c->moving_gc_wq = alloc_workqueue("bcache_gc",
1834 WQ_MEM_RECLAIM, 0)) ||
1835 bch_journal_alloc(c) ||
1836 bch_btree_cache_alloc(c) ||
1837 bch_open_buckets_alloc(c) ||
1838 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1839 goto err;
1840
1841 c->congested_read_threshold_us = 2000;
1842 c->congested_write_threshold_us = 20000;
1843 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1844 c->idle_max_writeback_rate_enabled = 1;
1845 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1846
1847 return c;
1848 err:
1849 bch_cache_set_unregister(c);
1850 return NULL;
1851 }
1852
1853 static int run_cache_set(struct cache_set *c)
1854 {
1855 const char *err = "cannot allocate memory";
1856 struct cached_dev *dc, *t;
1857 struct cache *ca;
1858 struct closure cl;
1859 unsigned int i;
1860 LIST_HEAD(journal);
1861 struct journal_replay *l;
1862
1863 closure_init_stack(&cl);
1864
1865 for_each_cache(ca, c, i)
1866 c->nbuckets += ca->sb.nbuckets;
1867 set_gc_sectors(c);
1868
1869 if (CACHE_SYNC(&c->sb)) {
1870 struct bkey *k;
1871 struct jset *j;
1872
1873 err = "cannot allocate memory for journal";
1874 if (bch_journal_read(c, &journal))
1875 goto err;
1876
1877 pr_debug("btree_journal_read() done");
1878
1879 err = "no journal entries found";
1880 if (list_empty(&journal))
1881 goto err;
1882
1883 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1884
1885 err = "IO error reading priorities";
1886 for_each_cache(ca, c, i) {
1887 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
1888 goto err;
1889 }
1890
1891 /*
1892 * If prio_read() fails it'll call cache_set_error and we'll
1893 * tear everything down right away, but if we perhaps checked
1894 * sooner we could avoid journal replay.
1895 */
1896
1897 k = &j->btree_root;
1898
1899 err = "bad btree root";
1900 if (__bch_btree_ptr_invalid(c, k))
1901 goto err;
1902
1903 err = "error reading btree root";
1904 c->root = bch_btree_node_get(c, NULL, k,
1905 j->btree_level,
1906 true, NULL);
1907 if (IS_ERR_OR_NULL(c->root))
1908 goto err;
1909
1910 list_del_init(&c->root->list);
1911 rw_unlock(true, c->root);
1912
1913 err = uuid_read(c, j, &cl);
1914 if (err)
1915 goto err;
1916
1917 err = "error in recovery";
1918 if (bch_btree_check(c))
1919 goto err;
1920
1921 bch_journal_mark(c, &journal);
1922 bch_initial_gc_finish(c);
1923 pr_debug("btree_check() done");
1924
1925 /*
1926 * bcache_journal_next() can't happen sooner, or
1927 * btree_gc_finish() will give spurious errors about last_gc >
1928 * gc_gen - this is a hack but oh well.
1929 */
1930 bch_journal_next(&c->journal);
1931
1932 err = "error starting allocator thread";
1933 for_each_cache(ca, c, i)
1934 if (bch_cache_allocator_start(ca))
1935 goto err;
1936
1937 /*
1938 * First place it's safe to allocate: btree_check() and
1939 * btree_gc_finish() have to run before we have buckets to
1940 * allocate, and bch_bucket_alloc_set() might cause a journal
1941 * entry to be written so bcache_journal_next() has to be called
1942 * first.
1943 *
1944 * If the uuids were in the old format we have to rewrite them
1945 * before the next journal entry is written:
1946 */
1947 if (j->version < BCACHE_JSET_VERSION_UUID)
1948 __uuid_write(c);
1949
1950 err = "bcache: replay journal failed";
1951 if (bch_journal_replay(c, &journal))
1952 goto err;
1953 } else {
1954 pr_notice("invalidating existing data");
1955
1956 for_each_cache(ca, c, i) {
1957 unsigned int j;
1958
1959 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
1960 2, SB_JOURNAL_BUCKETS);
1961
1962 for (j = 0; j < ca->sb.keys; j++)
1963 ca->sb.d[j] = ca->sb.first_bucket + j;
1964 }
1965
1966 bch_initial_gc_finish(c);
1967
1968 err = "error starting allocator thread";
1969 for_each_cache(ca, c, i)
1970 if (bch_cache_allocator_start(ca))
1971 goto err;
1972
1973 mutex_lock(&c->bucket_lock);
1974 for_each_cache(ca, c, i)
1975 bch_prio_write(ca, true);
1976 mutex_unlock(&c->bucket_lock);
1977
1978 err = "cannot allocate new UUID bucket";
1979 if (__uuid_write(c))
1980 goto err;
1981
1982 err = "cannot allocate new btree root";
1983 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
1984 if (IS_ERR_OR_NULL(c->root))
1985 goto err;
1986
1987 mutex_lock(&c->root->write_lock);
1988 bkey_copy_key(&c->root->key, &MAX_KEY);
1989 bch_btree_node_write(c->root, &cl);
1990 mutex_unlock(&c->root->write_lock);
1991
1992 bch_btree_set_root(c->root);
1993 rw_unlock(true, c->root);
1994
1995 /*
1996 * We don't want to write the first journal entry until
1997 * everything is set up - fortunately journal entries won't be
1998 * written until the SET_CACHE_SYNC() here:
1999 */
2000 SET_CACHE_SYNC(&c->sb, true);
2001
2002 bch_journal_next(&c->journal);
2003 bch_journal_meta(c, &cl);
2004 }
2005
2006 err = "error starting gc thread";
2007 if (bch_gc_thread_start(c))
2008 goto err;
2009
2010 closure_sync(&cl);
2011 c->sb.last_mount = (u32)ktime_get_real_seconds();
2012 bcache_write_super(c);
2013
2014 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2015 bch_cached_dev_attach(dc, c, NULL);
2016
2017 flash_devs_run(c);
2018
2019 set_bit(CACHE_SET_RUNNING, &c->flags);
2020 return 0;
2021 err:
2022 while (!list_empty(&journal)) {
2023 l = list_first_entry(&journal, struct journal_replay, list);
2024 list_del(&l->list);
2025 kfree(l);
2026 }
2027
2028 closure_sync(&cl);
2029
2030 bch_cache_set_error(c, "%s", err);
2031
2032 return -EIO;
2033 }
2034
2035 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
2036 {
2037 return ca->sb.block_size == c->sb.block_size &&
2038 ca->sb.bucket_size == c->sb.bucket_size &&
2039 ca->sb.nr_in_set == c->sb.nr_in_set;
2040 }
2041
2042 static const char *register_cache_set(struct cache *ca)
2043 {
2044 char buf[12];
2045 const char *err = "cannot allocate memory";
2046 struct cache_set *c;
2047
2048 list_for_each_entry(c, &bch_cache_sets, list)
2049 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
2050 if (c->cache[ca->sb.nr_this_dev])
2051 return "duplicate cache set member";
2052
2053 if (!can_attach_cache(ca, c))
2054 return "cache sb does not match set";
2055
2056 if (!CACHE_SYNC(&ca->sb))
2057 SET_CACHE_SYNC(&c->sb, false);
2058
2059 goto found;
2060 }
2061
2062 c = bch_cache_set_alloc(&ca->sb);
2063 if (!c)
2064 return err;
2065
2066 err = "error creating kobject";
2067 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
2068 kobject_add(&c->internal, &c->kobj, "internal"))
2069 goto err;
2070
2071 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2072 goto err;
2073
2074 bch_debug_init_cache_set(c);
2075
2076 list_add(&c->list, &bch_cache_sets);
2077 found:
2078 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2079 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2080 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2081 goto err;
2082
2083 if (ca->sb.seq > c->sb.seq) {
2084 c->sb.version = ca->sb.version;
2085 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2086 c->sb.flags = ca->sb.flags;
2087 c->sb.seq = ca->sb.seq;
2088 pr_debug("set version = %llu", c->sb.version);
2089 }
2090
2091 kobject_get(&ca->kobj);
2092 ca->set = c;
2093 ca->set->cache[ca->sb.nr_this_dev] = ca;
2094 c->cache_by_alloc[c->caches_loaded++] = ca;
2095
2096 if (c->caches_loaded == c->sb.nr_in_set) {
2097 err = "failed to run cache set";
2098 if (run_cache_set(c) < 0)
2099 goto err;
2100 }
2101
2102 return NULL;
2103 err:
2104 bch_cache_set_unregister(c);
2105 return err;
2106 }
2107
2108 /* Cache device */
2109
2110 /* When ca->kobj released */
2111 void bch_cache_release(struct kobject *kobj)
2112 {
2113 struct cache *ca = container_of(kobj, struct cache, kobj);
2114 unsigned int i;
2115
2116 if (ca->set) {
2117 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca);
2118 ca->set->cache[ca->sb.nr_this_dev] = NULL;
2119 }
2120
2121 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
2122 kfree(ca->prio_buckets);
2123 vfree(ca->buckets);
2124
2125 free_heap(&ca->heap);
2126 free_fifo(&ca->free_inc);
2127
2128 for (i = 0; i < RESERVE_NR; i++)
2129 free_fifo(&ca->free[i]);
2130
2131 if (ca->sb_disk)
2132 put_page(virt_to_page(ca->sb_disk));
2133
2134 if (!IS_ERR_OR_NULL(ca->bdev))
2135 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2136
2137 kfree(ca);
2138 module_put(THIS_MODULE);
2139 }
2140
2141 static int cache_alloc(struct cache *ca)
2142 {
2143 size_t free;
2144 size_t btree_buckets;
2145 struct bucket *b;
2146 int ret = -ENOMEM;
2147 const char *err = NULL;
2148
2149 __module_get(THIS_MODULE);
2150 kobject_init(&ca->kobj, &bch_cache_ktype);
2151
2152 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2153
2154 /*
2155 * when ca->sb.njournal_buckets is not zero, journal exists,
2156 * and in bch_journal_replay(), tree node may split,
2157 * so bucket of RESERVE_BTREE type is needed,
2158 * the worst situation is all journal buckets are valid journal,
2159 * and all the keys need to replay,
2160 * so the number of RESERVE_BTREE type buckets should be as much
2161 * as journal buckets
2162 */
2163 btree_buckets = ca->sb.njournal_buckets ?: 8;
2164 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2165 if (!free) {
2166 ret = -EPERM;
2167 err = "ca->sb.nbuckets is too small";
2168 goto err_free;
2169 }
2170
2171 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2172 GFP_KERNEL)) {
2173 err = "ca->free[RESERVE_BTREE] alloc failed";
2174 goto err_btree_alloc;
2175 }
2176
2177 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2178 GFP_KERNEL)) {
2179 err = "ca->free[RESERVE_PRIO] alloc failed";
2180 goto err_prio_alloc;
2181 }
2182
2183 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2184 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2185 goto err_movinggc_alloc;
2186 }
2187
2188 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2189 err = "ca->free[RESERVE_NONE] alloc failed";
2190 goto err_none_alloc;
2191 }
2192
2193 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2194 err = "ca->free_inc alloc failed";
2195 goto err_free_inc_alloc;
2196 }
2197
2198 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2199 err = "ca->heap alloc failed";
2200 goto err_heap_alloc;
2201 }
2202
2203 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2204 ca->sb.nbuckets));
2205 if (!ca->buckets) {
2206 err = "ca->buckets alloc failed";
2207 goto err_buckets_alloc;
2208 }
2209
2210 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2211 prio_buckets(ca), 2),
2212 GFP_KERNEL);
2213 if (!ca->prio_buckets) {
2214 err = "ca->prio_buckets alloc failed";
2215 goto err_prio_buckets_alloc;
2216 }
2217
2218 ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca);
2219 if (!ca->disk_buckets) {
2220 err = "ca->disk_buckets alloc failed";
2221 goto err_disk_buckets_alloc;
2222 }
2223
2224 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2225
2226 for_each_bucket(b, ca)
2227 atomic_set(&b->pin, 0);
2228 return 0;
2229
2230 err_disk_buckets_alloc:
2231 kfree(ca->prio_buckets);
2232 err_prio_buckets_alloc:
2233 vfree(ca->buckets);
2234 err_buckets_alloc:
2235 free_heap(&ca->heap);
2236 err_heap_alloc:
2237 free_fifo(&ca->free_inc);
2238 err_free_inc_alloc:
2239 free_fifo(&ca->free[RESERVE_NONE]);
2240 err_none_alloc:
2241 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2242 err_movinggc_alloc:
2243 free_fifo(&ca->free[RESERVE_PRIO]);
2244 err_prio_alloc:
2245 free_fifo(&ca->free[RESERVE_BTREE]);
2246 err_btree_alloc:
2247 err_free:
2248 module_put(THIS_MODULE);
2249 if (err)
2250 pr_notice("error %s: %s", ca->cache_dev_name, err);
2251 return ret;
2252 }
2253
2254 static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2255 struct block_device *bdev, struct cache *ca)
2256 {
2257 const char *err = NULL; /* must be set for any error case */
2258 int ret = 0;
2259
2260 bdevname(bdev, ca->cache_dev_name);
2261 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2262 ca->bdev = bdev;
2263 ca->bdev->bd_holder = ca;
2264 ca->sb_disk = sb_disk;
2265
2266 if (blk_queue_discard(bdev_get_queue(bdev)))
2267 ca->discard = CACHE_DISCARD(&ca->sb);
2268
2269 ret = cache_alloc(ca);
2270 if (ret != 0) {
2271 /*
2272 * If we failed here, it means ca->kobj is not initialized yet,
2273 * kobject_put() won't be called and there is no chance to
2274 * call blkdev_put() to bdev in bch_cache_release(). So we
2275 * explicitly call blkdev_put() here.
2276 */
2277 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2278 if (ret == -ENOMEM)
2279 err = "cache_alloc(): -ENOMEM";
2280 else if (ret == -EPERM)
2281 err = "cache_alloc(): cache device is too small";
2282 else
2283 err = "cache_alloc(): unknown error";
2284 goto err;
2285 }
2286
2287 if (kobject_add(&ca->kobj,
2288 &part_to_dev(bdev->bd_part)->kobj,
2289 "bcache")) {
2290 err = "error calling kobject_add";
2291 ret = -ENOMEM;
2292 goto out;
2293 }
2294
2295 mutex_lock(&bch_register_lock);
2296 err = register_cache_set(ca);
2297 mutex_unlock(&bch_register_lock);
2298
2299 if (err) {
2300 ret = -ENODEV;
2301 goto out;
2302 }
2303
2304 pr_info("registered cache device %s", ca->cache_dev_name);
2305
2306 out:
2307 kobject_put(&ca->kobj);
2308
2309 err:
2310 if (err)
2311 pr_notice("error %s: %s", ca->cache_dev_name, err);
2312
2313 return ret;
2314 }
2315
2316 /* Global interfaces/init */
2317
2318 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2319 const char *buffer, size_t size);
2320 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2321 struct kobj_attribute *attr,
2322 const char *buffer, size_t size);
2323
2324 kobj_attribute_write(register, register_bcache);
2325 kobj_attribute_write(register_quiet, register_bcache);
2326 kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2327
2328 static bool bch_is_open_backing(struct block_device *bdev)
2329 {
2330 struct cache_set *c, *tc;
2331 struct cached_dev *dc, *t;
2332
2333 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2334 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2335 if (dc->bdev == bdev)
2336 return true;
2337 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2338 if (dc->bdev == bdev)
2339 return true;
2340 return false;
2341 }
2342
2343 static bool bch_is_open_cache(struct block_device *bdev)
2344 {
2345 struct cache_set *c, *tc;
2346 struct cache *ca;
2347 unsigned int i;
2348
2349 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2350 for_each_cache(ca, c, i)
2351 if (ca->bdev == bdev)
2352 return true;
2353 return false;
2354 }
2355
2356 static bool bch_is_open(struct block_device *bdev)
2357 {
2358 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
2359 }
2360
2361 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2362 const char *buffer, size_t size)
2363 {
2364 const char *err;
2365 char *path = NULL;
2366 struct cache_sb *sb;
2367 struct cache_sb_disk *sb_disk;
2368 struct block_device *bdev;
2369 ssize_t ret;
2370
2371 ret = -EBUSY;
2372 err = "failed to reference bcache module";
2373 if (!try_module_get(THIS_MODULE))
2374 goto out;
2375
2376 /* For latest state of bcache_is_reboot */
2377 smp_mb();
2378 err = "bcache is in reboot";
2379 if (bcache_is_reboot)
2380 goto out_module_put;
2381
2382 ret = -ENOMEM;
2383 err = "cannot allocate memory";
2384 path = kstrndup(buffer, size, GFP_KERNEL);
2385 if (!path)
2386 goto out_module_put;
2387
2388 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2389 if (!sb)
2390 goto out_free_path;
2391
2392 ret = -EINVAL;
2393 err = "failed to open device";
2394 bdev = blkdev_get_by_path(strim(path),
2395 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2396 sb);
2397 if (IS_ERR(bdev)) {
2398 if (bdev == ERR_PTR(-EBUSY)) {
2399 bdev = lookup_bdev(strim(path));
2400 mutex_lock(&bch_register_lock);
2401 if (!IS_ERR(bdev) && bch_is_open(bdev))
2402 err = "device already registered";
2403 else
2404 err = "device busy";
2405 mutex_unlock(&bch_register_lock);
2406 if (!IS_ERR(bdev))
2407 bdput(bdev);
2408 if (attr == &ksysfs_register_quiet)
2409 goto done;
2410 }
2411 goto out_free_sb;
2412 }
2413
2414 err = "failed to set blocksize";
2415 if (set_blocksize(bdev, 4096))
2416 goto out_blkdev_put;
2417
2418 err = read_super(sb, bdev, &sb_disk);
2419 if (err)
2420 goto out_blkdev_put;
2421
2422 err = "failed to register device";
2423 if (SB_IS_BDEV(sb)) {
2424 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2425
2426 if (!dc)
2427 goto out_put_sb_page;
2428
2429 mutex_lock(&bch_register_lock);
2430 ret = register_bdev(sb, sb_disk, bdev, dc);
2431 mutex_unlock(&bch_register_lock);
2432 /* blkdev_put() will be called in cached_dev_free() */
2433 if (ret < 0)
2434 goto out_free_sb;
2435 } else {
2436 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2437
2438 if (!ca)
2439 goto out_put_sb_page;
2440
2441 /* blkdev_put() will be called in bch_cache_release() */
2442 if (register_cache(sb, sb_disk, bdev, ca) != 0)
2443 goto out_free_sb;
2444 }
2445
2446 done:
2447 kfree(sb);
2448 kfree(path);
2449 module_put(THIS_MODULE);
2450 return size;
2451
2452 out_put_sb_page:
2453 put_page(virt_to_page(sb_disk));
2454 out_blkdev_put:
2455 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2456 out_free_sb:
2457 kfree(sb);
2458 out_free_path:
2459 kfree(path);
2460 path = NULL;
2461 out_module_put:
2462 module_put(THIS_MODULE);
2463 out:
2464 pr_info("error %s: %s", path?path:"", err);
2465 return ret;
2466 }
2467
2468
2469 struct pdev {
2470 struct list_head list;
2471 struct cached_dev *dc;
2472 };
2473
2474 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2475 struct kobj_attribute *attr,
2476 const char *buffer,
2477 size_t size)
2478 {
2479 LIST_HEAD(pending_devs);
2480 ssize_t ret = size;
2481 struct cached_dev *dc, *tdc;
2482 struct pdev *pdev, *tpdev;
2483 struct cache_set *c, *tc;
2484
2485 mutex_lock(&bch_register_lock);
2486 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2487 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2488 if (!pdev)
2489 break;
2490 pdev->dc = dc;
2491 list_add(&pdev->list, &pending_devs);
2492 }
2493
2494 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2495 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2496 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2497 char *set_uuid = c->sb.uuid;
2498
2499 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2500 list_del(&pdev->list);
2501 kfree(pdev);
2502 break;
2503 }
2504 }
2505 }
2506 mutex_unlock(&bch_register_lock);
2507
2508 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2509 pr_info("delete pdev %p", pdev);
2510 list_del(&pdev->list);
2511 bcache_device_stop(&pdev->dc->disk);
2512 kfree(pdev);
2513 }
2514
2515 return ret;
2516 }
2517
2518 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2519 {
2520 if (bcache_is_reboot)
2521 return NOTIFY_DONE;
2522
2523 if (code == SYS_DOWN ||
2524 code == SYS_HALT ||
2525 code == SYS_POWER_OFF) {
2526 DEFINE_WAIT(wait);
2527 unsigned long start = jiffies;
2528 bool stopped = false;
2529
2530 struct cache_set *c, *tc;
2531 struct cached_dev *dc, *tdc;
2532
2533 mutex_lock(&bch_register_lock);
2534
2535 if (bcache_is_reboot)
2536 goto out;
2537
2538 /* New registration is rejected since now */
2539 bcache_is_reboot = true;
2540 /*
2541 * Make registering caller (if there is) on other CPU
2542 * core know bcache_is_reboot set to true earlier
2543 */
2544 smp_mb();
2545
2546 if (list_empty(&bch_cache_sets) &&
2547 list_empty(&uncached_devices))
2548 goto out;
2549
2550 mutex_unlock(&bch_register_lock);
2551
2552 pr_info("Stopping all devices:");
2553
2554 /*
2555 * The reason bch_register_lock is not held to call
2556 * bch_cache_set_stop() and bcache_device_stop() is to
2557 * avoid potential deadlock during reboot, because cache
2558 * set or bcache device stopping process will acqurie
2559 * bch_register_lock too.
2560 *
2561 * We are safe here because bcache_is_reboot sets to
2562 * true already, register_bcache() will reject new
2563 * registration now. bcache_is_reboot also makes sure
2564 * bcache_reboot() won't be re-entered on by other thread,
2565 * so there is no race in following list iteration by
2566 * list_for_each_entry_safe().
2567 */
2568 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2569 bch_cache_set_stop(c);
2570
2571 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2572 bcache_device_stop(&dc->disk);
2573
2574
2575 /*
2576 * Give an early chance for other kthreads and
2577 * kworkers to stop themselves
2578 */
2579 schedule();
2580
2581 /* What's a condition variable? */
2582 while (1) {
2583 long timeout = start + 10 * HZ - jiffies;
2584
2585 mutex_lock(&bch_register_lock);
2586 stopped = list_empty(&bch_cache_sets) &&
2587 list_empty(&uncached_devices);
2588
2589 if (timeout < 0 || stopped)
2590 break;
2591
2592 prepare_to_wait(&unregister_wait, &wait,
2593 TASK_UNINTERRUPTIBLE);
2594
2595 mutex_unlock(&bch_register_lock);
2596 schedule_timeout(timeout);
2597 }
2598
2599 finish_wait(&unregister_wait, &wait);
2600
2601 if (stopped)
2602 pr_info("All devices stopped");
2603 else
2604 pr_notice("Timeout waiting for devices to be closed");
2605 out:
2606 mutex_unlock(&bch_register_lock);
2607 }
2608
2609 return NOTIFY_DONE;
2610 }
2611
2612 static struct notifier_block reboot = {
2613 .notifier_call = bcache_reboot,
2614 .priority = INT_MAX, /* before any real devices */
2615 };
2616
2617 static void bcache_exit(void)
2618 {
2619 bch_debug_exit();
2620 bch_request_exit();
2621 if (bcache_kobj)
2622 kobject_put(bcache_kobj);
2623 if (bcache_wq)
2624 destroy_workqueue(bcache_wq);
2625 if (bch_journal_wq)
2626 destroy_workqueue(bch_journal_wq);
2627
2628 if (bcache_major)
2629 unregister_blkdev(bcache_major, "bcache");
2630 unregister_reboot_notifier(&reboot);
2631 mutex_destroy(&bch_register_lock);
2632 }
2633
2634 /* Check and fixup module parameters */
2635 static void check_module_parameters(void)
2636 {
2637 if (bch_cutoff_writeback_sync == 0)
2638 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2639 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2640 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u",
2641 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2642 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2643 }
2644
2645 if (bch_cutoff_writeback == 0)
2646 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2647 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2648 pr_warn("set bch_cutoff_writeback (%u) to max value %u",
2649 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2650 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2651 }
2652
2653 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2654 pr_warn("set bch_cutoff_writeback (%u) to %u",
2655 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2656 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2657 }
2658 }
2659
2660 static int __init bcache_init(void)
2661 {
2662 static const struct attribute *files[] = {
2663 &ksysfs_register.attr,
2664 &ksysfs_register_quiet.attr,
2665 &ksysfs_pendings_cleanup.attr,
2666 NULL
2667 };
2668
2669 check_module_parameters();
2670
2671 mutex_init(&bch_register_lock);
2672 init_waitqueue_head(&unregister_wait);
2673 register_reboot_notifier(&reboot);
2674
2675 bcache_major = register_blkdev(0, "bcache");
2676 if (bcache_major < 0) {
2677 unregister_reboot_notifier(&reboot);
2678 mutex_destroy(&bch_register_lock);
2679 return bcache_major;
2680 }
2681
2682 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2683 if (!bcache_wq)
2684 goto err;
2685
2686 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2687 if (!bch_journal_wq)
2688 goto err;
2689
2690 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2691 if (!bcache_kobj)
2692 goto err;
2693
2694 if (bch_request_init() ||
2695 sysfs_create_files(bcache_kobj, files))
2696 goto err;
2697
2698 bch_debug_init();
2699 closure_debug_init();
2700
2701 bcache_is_reboot = false;
2702
2703 return 0;
2704 err:
2705 bcache_exit();
2706 return -ENOMEM;
2707 }
2708
2709 /*
2710 * Module hooks
2711 */
2712 module_exit(bcache_exit);
2713 module_init(bcache_init);
2714
2715 module_param(bch_cutoff_writeback, uint, 0);
2716 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2717
2718 module_param(bch_cutoff_writeback_sync, uint, 0);
2719 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2720
2721 MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2722 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2723 MODULE_LICENSE("GPL");
Linux with added FPC-III support