1 // SPDX-License-Identifier: GPL-2.0
3 * bcache setup/teardown code, and some metadata io - read a superblock and
4 * figure out what to do with it.
6 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
7 * Copyright 2012 Google, Inc.
15 #include "writeback.h"
17 #include <linux/blkdev.h>
18 #include <linux/buffer_head.h>
19 #include <linux/debugfs.h>
20 #include <linux/genhd.h>
21 #include <linux/idr.h>
22 #include <linux/kthread.h>
23 #include <linux/module.h>
24 #include <linux/random.h>
25 #include <linux/reboot.h>
26 #include <linux/sysfs.h>
28 unsigned int bch_cutoff_writeback;
29 unsigned int bch_cutoff_writeback_sync;
31 static const char bcache_magic[] = {
32 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
33 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
36 static const char invalid_uuid[] = {
37 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
38 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
41 static struct kobject *bcache_kobj;
42 struct mutex bch_register_lock;
43 LIST_HEAD(bch_cache_sets);
44 static LIST_HEAD(uncached_devices);
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;
52 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
53 /* limitation of partitions number on single bcache device */
54 #define BCACHE_MINORS 128
55 /* limitation of bcache devices number on single system */
56 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
60 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
65 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
71 s = (struct cache_sb *) bh->b_data;
73 sb->offset = le64_to_cpu(s->offset);
74 sb->version = le64_to_cpu(s->version);
76 memcpy(sb->magic, s->magic, 16);
77 memcpy(sb->uuid, s->uuid, 16);
78 memcpy(sb->set_uuid, s->set_uuid, 16);
79 memcpy(sb->label, s->label, SB_LABEL_SIZE);
81 sb->flags = le64_to_cpu(s->flags);
82 sb->seq = le64_to_cpu(s->seq);
83 sb->last_mount = le32_to_cpu(s->last_mount);
84 sb->first_bucket = le16_to_cpu(s->first_bucket);
85 sb->keys = le16_to_cpu(s->keys);
87 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
88 sb->d[i] = le64_to_cpu(s->d[i]);
90 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
91 sb->version, sb->flags, sb->seq, sb->keys);
93 err = "Not a bcache superblock";
94 if (sb->offset != SB_SECTOR)
97 if (memcmp(sb->magic, bcache_magic, 16))
100 err = "Too many journal buckets";
101 if (sb->keys > SB_JOURNAL_BUCKETS)
104 err = "Bad checksum";
105 if (s->csum != csum_set(s))
109 if (bch_is_zero(sb->uuid, 16))
112 sb->block_size = le16_to_cpu(s->block_size);
114 err = "Superblock block size smaller than device block size";
115 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
118 switch (sb->version) {
119 case BCACHE_SB_VERSION_BDEV:
120 sb->data_offset = BDEV_DATA_START_DEFAULT;
122 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
123 sb->data_offset = le64_to_cpu(s->data_offset);
125 err = "Bad data offset";
126 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
130 case BCACHE_SB_VERSION_CDEV:
131 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
132 sb->nbuckets = le64_to_cpu(s->nbuckets);
133 sb->bucket_size = le16_to_cpu(s->bucket_size);
135 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
136 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
138 err = "Too many buckets";
139 if (sb->nbuckets > LONG_MAX)
142 err = "Not enough buckets";
143 if (sb->nbuckets < 1 << 7)
146 err = "Bad block/bucket size";
147 if (!is_power_of_2(sb->block_size) ||
148 sb->block_size > PAGE_SECTORS ||
149 !is_power_of_2(sb->bucket_size) ||
150 sb->bucket_size < PAGE_SECTORS)
153 err = "Invalid superblock: device too small";
154 if (get_capacity(bdev->bd_disk) <
155 sb->bucket_size * sb->nbuckets)
159 if (bch_is_zero(sb->set_uuid, 16))
162 err = "Bad cache device number in set";
163 if (!sb->nr_in_set ||
164 sb->nr_in_set <= sb->nr_this_dev ||
165 sb->nr_in_set > MAX_CACHES_PER_SET)
168 err = "Journal buckets not sequential";
169 for (i = 0; i < sb->keys; i++)
170 if (sb->d[i] != sb->first_bucket + i)
173 err = "Too many journal buckets";
174 if (sb->first_bucket + sb->keys > sb->nbuckets)
177 err = "Invalid superblock: first bucket comes before end of super";
178 if (sb->first_bucket * sb->bucket_size < 16)
183 err = "Unsupported superblock version";
187 sb->last_mount = (u32)ktime_get_real_seconds();
190 get_page(bh->b_page);
197 static void write_bdev_super_endio(struct bio *bio)
199 struct cached_dev *dc = bio->bi_private;
200 /* XXX: error checking */
202 closure_put(&dc->sb_write);
205 static void __write_super(struct cache_sb *sb, struct bio *bio)
207 struct cache_sb *out = page_address(bio_first_page_all(bio));
210 bio->bi_iter.bi_sector = SB_SECTOR;
211 bio->bi_iter.bi_size = SB_SIZE;
212 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META);
213 bch_bio_map(bio, NULL);
215 out->offset = cpu_to_le64(sb->offset);
216 out->version = cpu_to_le64(sb->version);
218 memcpy(out->uuid, sb->uuid, 16);
219 memcpy(out->set_uuid, sb->set_uuid, 16);
220 memcpy(out->label, sb->label, SB_LABEL_SIZE);
222 out->flags = cpu_to_le64(sb->flags);
223 out->seq = cpu_to_le64(sb->seq);
225 out->last_mount = cpu_to_le32(sb->last_mount);
226 out->first_bucket = cpu_to_le16(sb->first_bucket);
227 out->keys = cpu_to_le16(sb->keys);
229 for (i = 0; i < sb->keys; i++)
230 out->d[i] = cpu_to_le64(sb->d[i]);
232 out->csum = csum_set(out);
234 pr_debug("ver %llu, flags %llu, seq %llu",
235 sb->version, sb->flags, sb->seq);
240 static void bch_write_bdev_super_unlock(struct closure *cl)
242 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
244 up(&dc->sb_write_mutex);
247 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
249 struct closure *cl = &dc->sb_write;
250 struct bio *bio = &dc->sb_bio;
252 down(&dc->sb_write_mutex);
253 closure_init(cl, parent);
256 bio_set_dev(bio, dc->bdev);
257 bio->bi_end_io = write_bdev_super_endio;
258 bio->bi_private = dc;
261 /* I/O request sent to backing device */
262 __write_super(&dc->sb, bio);
264 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
267 static void write_super_endio(struct bio *bio)
269 struct cache *ca = bio->bi_private;
272 bch_count_io_errors(ca, bio->bi_status, 0,
273 "writing superblock");
274 closure_put(&ca->set->sb_write);
277 static void bcache_write_super_unlock(struct closure *cl)
279 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
281 up(&c->sb_write_mutex);
284 void bcache_write_super(struct cache_set *c)
286 struct closure *cl = &c->sb_write;
290 down(&c->sb_write_mutex);
291 closure_init(cl, &c->cl);
295 for_each_cache(ca, c, i) {
296 struct bio *bio = &ca->sb_bio;
298 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
299 ca->sb.seq = c->sb.seq;
300 ca->sb.last_mount = c->sb.last_mount;
302 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
305 bio_set_dev(bio, ca->bdev);
306 bio->bi_end_io = write_super_endio;
307 bio->bi_private = ca;
310 __write_super(&ca->sb, bio);
313 closure_return_with_destructor(cl, bcache_write_super_unlock);
318 static void uuid_endio(struct bio *bio)
320 struct closure *cl = bio->bi_private;
321 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
323 cache_set_err_on(bio->bi_status, c, "accessing uuids");
324 bch_bbio_free(bio, c);
328 static void uuid_io_unlock(struct closure *cl)
330 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
332 up(&c->uuid_write_mutex);
335 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
336 struct bkey *k, struct closure *parent)
338 struct closure *cl = &c->uuid_write;
339 struct uuid_entry *u;
344 down(&c->uuid_write_mutex);
345 closure_init(cl, parent);
347 for (i = 0; i < KEY_PTRS(k); i++) {
348 struct bio *bio = bch_bbio_alloc(c);
350 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
351 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
353 bio->bi_end_io = uuid_endio;
354 bio->bi_private = cl;
355 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
356 bch_bio_map(bio, c->uuids);
358 bch_submit_bbio(bio, c, k, i);
360 if (op != REQ_OP_WRITE)
364 bch_extent_to_text(buf, sizeof(buf), k);
365 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf);
367 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
368 if (!bch_is_zero(u->uuid, 16))
369 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
370 u - c->uuids, u->uuid, u->label,
371 u->first_reg, u->last_reg, u->invalidated);
373 closure_return_with_destructor(cl, uuid_io_unlock);
376 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
378 struct bkey *k = &j->uuid_bucket;
380 if (__bch_btree_ptr_invalid(c, k))
381 return "bad uuid pointer";
383 bkey_copy(&c->uuid_bucket, k);
384 uuid_io(c, REQ_OP_READ, 0, k, cl);
386 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
387 struct uuid_entry_v0 *u0 = (void *) c->uuids;
388 struct uuid_entry *u1 = (void *) c->uuids;
394 * Since the new uuid entry is bigger than the old, we have to
395 * convert starting at the highest memory address and work down
396 * in order to do it in place
399 for (i = c->nr_uuids - 1;
402 memcpy(u1[i].uuid, u0[i].uuid, 16);
403 memcpy(u1[i].label, u0[i].label, 32);
405 u1[i].first_reg = u0[i].first_reg;
406 u1[i].last_reg = u0[i].last_reg;
407 u1[i].invalidated = u0[i].invalidated;
417 static int __uuid_write(struct cache_set *c)
423 closure_init_stack(&cl);
424 lockdep_assert_held(&bch_register_lock);
426 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
429 SET_KEY_SIZE(&k.key, c->sb.bucket_size);
430 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
433 /* Only one bucket used for uuid write */
434 ca = PTR_CACHE(c, &k.key, 0);
435 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
437 bkey_copy(&c->uuid_bucket, &k.key);
442 int bch_uuid_write(struct cache_set *c)
444 int ret = __uuid_write(c);
447 bch_journal_meta(c, NULL);
452 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
454 struct uuid_entry *u;
457 u < c->uuids + c->nr_uuids; u++)
458 if (!memcmp(u->uuid, uuid, 16))
464 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
466 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
468 return uuid_find(c, zero_uuid);
472 * Bucket priorities/gens:
474 * For each bucket, we store on disk its
478 * See alloc.c for an explanation of the gen. The priority is used to implement
479 * lru (and in the future other) cache replacement policies; for most purposes
480 * it's just an opaque integer.
482 * The gens and the priorities don't have a whole lot to do with each other, and
483 * it's actually the gens that must be written out at specific times - it's no
484 * big deal if the priorities don't get written, if we lose them we just reuse
485 * buckets in suboptimal order.
487 * On disk they're stored in a packed array, and in as many buckets are required
488 * to fit them all. The buckets we use to store them form a list; the journal
489 * header points to the first bucket, the first bucket points to the second
492 * This code is used by the allocation code; periodically (whenever it runs out
493 * of buckets to allocate from) the allocation code will invalidate some
494 * buckets, but it can't use those buckets until their new gens are safely on
498 static void prio_endio(struct bio *bio)
500 struct cache *ca = bio->bi_private;
502 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
503 bch_bbio_free(bio, ca->set);
504 closure_put(&ca->prio);
507 static void prio_io(struct cache *ca, uint64_t bucket, int op,
508 unsigned long op_flags)
510 struct closure *cl = &ca->prio;
511 struct bio *bio = bch_bbio_alloc(ca->set);
513 closure_init_stack(cl);
515 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
516 bio_set_dev(bio, ca->bdev);
517 bio->bi_iter.bi_size = bucket_bytes(ca);
519 bio->bi_end_io = prio_endio;
520 bio->bi_private = ca;
521 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
522 bch_bio_map(bio, ca->disk_buckets);
524 closure_bio_submit(ca->set, bio, &ca->prio);
528 void bch_prio_write(struct cache *ca)
534 closure_init_stack(&cl);
536 lockdep_assert_held(&ca->set->bucket_lock);
538 ca->disk_buckets->seq++;
540 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
541 &ca->meta_sectors_written);
543 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free),
544 // fifo_used(&ca->free_inc), fifo_used(&ca->unused));
546 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
548 struct prio_set *p = ca->disk_buckets;
549 struct bucket_disk *d = p->data;
550 struct bucket_disk *end = d + prios_per_bucket(ca);
552 for (b = ca->buckets + i * prios_per_bucket(ca);
553 b < ca->buckets + ca->sb.nbuckets && d < end;
555 d->prio = cpu_to_le16(b->prio);
559 p->next_bucket = ca->prio_buckets[i + 1];
560 p->magic = pset_magic(&ca->sb);
561 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
563 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true);
564 BUG_ON(bucket == -1);
566 mutex_unlock(&ca->set->bucket_lock);
567 prio_io(ca, bucket, REQ_OP_WRITE, 0);
568 mutex_lock(&ca->set->bucket_lock);
570 ca->prio_buckets[i] = bucket;
571 atomic_dec_bug(&ca->buckets[bucket].pin);
574 mutex_unlock(&ca->set->bucket_lock);
576 bch_journal_meta(ca->set, &cl);
579 mutex_lock(&ca->set->bucket_lock);
582 * Don't want the old priorities to get garbage collected until after we
583 * finish writing the new ones, and they're journalled
585 for (i = 0; i < prio_buckets(ca); i++) {
586 if (ca->prio_last_buckets[i])
587 __bch_bucket_free(ca,
588 &ca->buckets[ca->prio_last_buckets[i]]);
590 ca->prio_last_buckets[i] = ca->prio_buckets[i];
594 static void prio_read(struct cache *ca, uint64_t bucket)
596 struct prio_set *p = ca->disk_buckets;
597 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
599 unsigned int bucket_nr = 0;
601 for (b = ca->buckets;
602 b < ca->buckets + ca->sb.nbuckets;
605 ca->prio_buckets[bucket_nr] = bucket;
606 ca->prio_last_buckets[bucket_nr] = bucket;
609 prio_io(ca, bucket, REQ_OP_READ, 0);
612 bch_crc64(&p->magic, bucket_bytes(ca) - 8))
613 pr_warn("bad csum reading priorities");
615 if (p->magic != pset_magic(&ca->sb))
616 pr_warn("bad magic reading priorities");
618 bucket = p->next_bucket;
622 b->prio = le16_to_cpu(d->prio);
623 b->gen = b->last_gc = d->gen;
629 static int open_dev(struct block_device *b, fmode_t mode)
631 struct bcache_device *d = b->bd_disk->private_data;
633 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
640 static void release_dev(struct gendisk *b, fmode_t mode)
642 struct bcache_device *d = b->private_data;
647 static int ioctl_dev(struct block_device *b, fmode_t mode,
648 unsigned int cmd, unsigned long arg)
650 struct bcache_device *d = b->bd_disk->private_data;
652 return d->ioctl(d, mode, cmd, arg);
655 static const struct block_device_operations bcache_ops = {
657 .release = release_dev,
659 .owner = THIS_MODULE,
662 void bcache_device_stop(struct bcache_device *d)
664 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
667 * - cached device: cached_dev_flush()
668 * - flash dev: flash_dev_flush()
670 closure_queue(&d->cl);
673 static void bcache_device_unlink(struct bcache_device *d)
675 lockdep_assert_held(&bch_register_lock);
677 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
681 sysfs_remove_link(&d->c->kobj, d->name);
682 sysfs_remove_link(&d->kobj, "cache");
684 for_each_cache(ca, d->c, i)
685 bd_unlink_disk_holder(ca->bdev, d->disk);
689 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
695 for_each_cache(ca, d->c, i)
696 bd_link_disk_holder(ca->bdev, d->disk);
698 snprintf(d->name, BCACHEDEVNAME_SIZE,
699 "%s%u", name, d->id);
701 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
702 sysfs_create_link(&c->kobj, &d->kobj, d->name),
703 "Couldn't create device <-> cache set symlinks");
705 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
708 static void bcache_device_detach(struct bcache_device *d)
710 lockdep_assert_held(&bch_register_lock);
712 atomic_dec(&d->c->attached_dev_nr);
714 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
715 struct uuid_entry *u = d->c->uuids + d->id;
717 SET_UUID_FLASH_ONLY(u, 0);
718 memcpy(u->uuid, invalid_uuid, 16);
719 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
720 bch_uuid_write(d->c);
723 bcache_device_unlink(d);
725 d->c->devices[d->id] = NULL;
726 closure_put(&d->c->caching);
730 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
737 if (id >= c->devices_max_used)
738 c->devices_max_used = id + 1;
740 closure_get(&c->caching);
743 static inline int first_minor_to_idx(int first_minor)
745 return (first_minor/BCACHE_MINORS);
748 static inline int idx_to_first_minor(int idx)
750 return (idx * BCACHE_MINORS);
753 static void bcache_device_free(struct bcache_device *d)
755 lockdep_assert_held(&bch_register_lock);
757 pr_info("%s stopped", d->disk->disk_name);
760 bcache_device_detach(d);
761 if (d->disk && d->disk->flags & GENHD_FL_UP)
762 del_gendisk(d->disk);
763 if (d->disk && d->disk->queue)
764 blk_cleanup_queue(d->disk->queue);
766 ida_simple_remove(&bcache_device_idx,
767 first_minor_to_idx(d->disk->first_minor));
771 bioset_exit(&d->bio_split);
772 kvfree(d->full_dirty_stripes);
773 kvfree(d->stripe_sectors_dirty);
775 closure_debug_destroy(&d->cl);
778 static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
781 struct request_queue *q;
782 const size_t max_stripes = min_t(size_t, INT_MAX,
783 SIZE_MAX / sizeof(atomic_t));
788 d->stripe_size = 1 << 31;
790 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
792 if (!d->nr_stripes || d->nr_stripes > max_stripes) {
793 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)",
794 (unsigned int)d->nr_stripes);
798 n = d->nr_stripes * sizeof(atomic_t);
799 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
800 if (!d->stripe_sectors_dirty)
803 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
804 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
805 if (!d->full_dirty_stripes)
808 idx = ida_simple_get(&bcache_device_idx, 0,
809 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
813 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
814 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
817 d->disk = alloc_disk(BCACHE_MINORS);
821 set_capacity(d->disk, sectors);
822 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
824 d->disk->major = bcache_major;
825 d->disk->first_minor = idx_to_first_minor(idx);
826 d->disk->fops = &bcache_ops;
827 d->disk->private_data = d;
829 q = blk_alloc_queue(GFP_KERNEL);
833 blk_queue_make_request(q, NULL);
836 q->backing_dev_info->congested_data = d;
837 q->limits.max_hw_sectors = UINT_MAX;
838 q->limits.max_sectors = UINT_MAX;
839 q->limits.max_segment_size = UINT_MAX;
840 q->limits.max_segments = BIO_MAX_PAGES;
841 blk_queue_max_discard_sectors(q, UINT_MAX);
842 q->limits.discard_granularity = 512;
843 q->limits.io_min = block_size;
844 q->limits.logical_block_size = block_size;
845 q->limits.physical_block_size = block_size;
846 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
847 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
848 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
850 blk_queue_write_cache(q, true, true);
855 ida_simple_remove(&bcache_device_idx, idx);
862 static void calc_cached_dev_sectors(struct cache_set *c)
864 uint64_t sectors = 0;
865 struct cached_dev *dc;
867 list_for_each_entry(dc, &c->cached_devs, list)
868 sectors += bdev_sectors(dc->bdev);
870 c->cached_dev_sectors = sectors;
873 #define BACKING_DEV_OFFLINE_TIMEOUT 5
874 static int cached_dev_status_update(void *arg)
876 struct cached_dev *dc = arg;
877 struct request_queue *q;
880 * If this delayed worker is stopping outside, directly quit here.
881 * dc->io_disable might be set via sysfs interface, so check it
884 while (!kthread_should_stop() && !dc->io_disable) {
885 q = bdev_get_queue(dc->bdev);
886 if (blk_queue_dying(q))
887 dc->offline_seconds++;
889 dc->offline_seconds = 0;
891 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
892 pr_err("%s: device offline for %d seconds",
893 dc->backing_dev_name,
894 BACKING_DEV_OFFLINE_TIMEOUT);
895 pr_err("%s: disable I/O request due to backing "
896 "device offline", dc->disk.name);
897 dc->io_disable = true;
898 /* let others know earlier that io_disable is true */
900 bcache_device_stop(&dc->disk);
903 schedule_timeout_interruptible(HZ);
906 wait_for_kthread_stop();
911 void bch_cached_dev_run(struct cached_dev *dc)
913 struct bcache_device *d = &dc->disk;
914 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
917 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
918 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
922 if (atomic_xchg(&dc->running, 1)) {
930 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
933 closure_init_stack(&cl);
935 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
936 bch_write_bdev_super(dc, &cl);
941 bd_link_disk_holder(dc->bdev, dc->disk.disk);
943 * won't show up in the uevent file, use udevadm monitor -e instead
944 * only class / kset properties are persistent
946 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
951 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
952 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
953 pr_debug("error creating sysfs link");
955 dc->status_update_thread = kthread_run(cached_dev_status_update,
956 dc, "bcache_status_update");
957 if (IS_ERR(dc->status_update_thread)) {
958 pr_warn("failed to create bcache_status_update kthread, "
959 "continue to run without monitoring backing "
965 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
966 * work dc->writeback_rate_update is running. Wait until the routine
967 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
968 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
969 * seconds, give up waiting here and continue to cancel it too.
971 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
973 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
976 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
980 schedule_timeout_interruptible(1);
981 } while (time_out > 0);
984 pr_warn("give up waiting for dc->writeback_write_update to quit");
986 cancel_delayed_work_sync(&dc->writeback_rate_update);
989 static void cached_dev_detach_finish(struct work_struct *w)
991 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
994 closure_init_stack(&cl);
996 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
997 BUG_ON(refcount_read(&dc->count));
999 mutex_lock(&bch_register_lock);
1001 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1002 cancel_writeback_rate_update_dwork(dc);
1004 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1005 kthread_stop(dc->writeback_thread);
1006 dc->writeback_thread = NULL;
1009 memset(&dc->sb.set_uuid, 0, 16);
1010 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
1012 bch_write_bdev_super(dc, &cl);
1015 calc_cached_dev_sectors(dc->disk.c);
1016 bcache_device_detach(&dc->disk);
1017 list_move(&dc->list, &uncached_devices);
1019 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1020 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1022 mutex_unlock(&bch_register_lock);
1024 pr_info("Caching disabled for %s", dc->backing_dev_name);
1026 /* Drop ref we took in cached_dev_detach() */
1027 closure_put(&dc->disk.cl);
1030 void bch_cached_dev_detach(struct cached_dev *dc)
1032 lockdep_assert_held(&bch_register_lock);
1034 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1037 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1041 * Block the device from being closed and freed until we're finished
1044 closure_get(&dc->disk.cl);
1046 bch_writeback_queue(dc);
1051 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1054 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1055 struct uuid_entry *u;
1056 struct cached_dev *exist_dc, *t;
1058 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
1059 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
1063 pr_err("Can't attach %s: already attached",
1064 dc->backing_dev_name);
1068 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1069 pr_err("Can't attach %s: shutting down",
1070 dc->backing_dev_name);
1074 if (dc->sb.block_size < c->sb.block_size) {
1076 pr_err("Couldn't attach %s: block size less than set's block size",
1077 dc->backing_dev_name);
1081 /* Check whether already attached */
1082 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1083 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1084 pr_err("Tried to attach %s but duplicate UUID already attached",
1085 dc->backing_dev_name);
1091 u = uuid_find(c, dc->sb.uuid);
1094 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1095 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1096 memcpy(u->uuid, invalid_uuid, 16);
1097 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1102 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1103 pr_err("Couldn't find uuid for %s in set",
1104 dc->backing_dev_name);
1108 u = uuid_find_empty(c);
1110 pr_err("Not caching %s, no room for UUID",
1111 dc->backing_dev_name);
1117 * Deadlocks since we're called via sysfs...
1118 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1121 if (bch_is_zero(u->uuid, 16)) {
1124 closure_init_stack(&cl);
1126 memcpy(u->uuid, dc->sb.uuid, 16);
1127 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1128 u->first_reg = u->last_reg = rtime;
1131 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
1132 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1134 bch_write_bdev_super(dc, &cl);
1137 u->last_reg = rtime;
1141 bcache_device_attach(&dc->disk, c, u - c->uuids);
1142 list_move(&dc->list, &c->cached_devs);
1143 calc_cached_dev_sectors(c);
1146 * dc->c must be set before dc->count != 0 - paired with the mb in
1150 refcount_set(&dc->count, 1);
1152 /* Block writeback thread, but spawn it */
1153 down_write(&dc->writeback_lock);
1154 if (bch_cached_dev_writeback_start(dc)) {
1155 up_write(&dc->writeback_lock);
1159 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1160 atomic_set(&dc->has_dirty, 1);
1161 bch_writeback_queue(dc);
1164 bch_sectors_dirty_init(&dc->disk);
1166 bch_cached_dev_run(dc);
1167 bcache_device_link(&dc->disk, c, "bdev");
1168 atomic_inc(&c->attached_dev_nr);
1170 /* Allow the writeback thread to proceed */
1171 up_write(&dc->writeback_lock);
1173 pr_info("Caching %s as %s on set %pU",
1174 dc->backing_dev_name,
1175 dc->disk.disk->disk_name,
1176 dc->disk.c->sb.set_uuid);
1180 /* when dc->disk.kobj released */
1181 void bch_cached_dev_release(struct kobject *kobj)
1183 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1186 module_put(THIS_MODULE);
1189 static void cached_dev_free(struct closure *cl)
1191 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1193 mutex_lock(&bch_register_lock);
1195 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1196 cancel_writeback_rate_update_dwork(dc);
1198 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1199 kthread_stop(dc->writeback_thread);
1200 if (dc->writeback_write_wq)
1201 destroy_workqueue(dc->writeback_write_wq);
1202 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1203 kthread_stop(dc->status_update_thread);
1205 if (atomic_read(&dc->running))
1206 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1207 bcache_device_free(&dc->disk);
1208 list_del(&dc->list);
1210 mutex_unlock(&bch_register_lock);
1212 if (!IS_ERR_OR_NULL(dc->bdev))
1213 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1215 wake_up(&unregister_wait);
1217 kobject_put(&dc->disk.kobj);
1220 static void cached_dev_flush(struct closure *cl)
1222 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1223 struct bcache_device *d = &dc->disk;
1225 mutex_lock(&bch_register_lock);
1226 bcache_device_unlink(d);
1227 mutex_unlock(&bch_register_lock);
1229 bch_cache_accounting_destroy(&dc->accounting);
1230 kobject_del(&d->kobj);
1232 continue_at(cl, cached_dev_free, system_wq);
1235 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1239 struct request_queue *q = bdev_get_queue(dc->bdev);
1241 __module_get(THIS_MODULE);
1242 INIT_LIST_HEAD(&dc->list);
1243 closure_init(&dc->disk.cl, NULL);
1244 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1245 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1246 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1247 sema_init(&dc->sb_write_mutex, 1);
1248 INIT_LIST_HEAD(&dc->io_lru);
1249 spin_lock_init(&dc->io_lock);
1250 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1252 dc->sequential_cutoff = 4 << 20;
1254 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1255 list_add(&io->lru, &dc->io_lru);
1256 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1259 dc->disk.stripe_size = q->limits.io_opt >> 9;
1261 if (dc->disk.stripe_size)
1262 dc->partial_stripes_expensive =
1263 q->limits.raid_partial_stripes_expensive;
1265 ret = bcache_device_init(&dc->disk, block_size,
1266 dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
1270 dc->disk.disk->queue->backing_dev_info->ra_pages =
1271 max(dc->disk.disk->queue->backing_dev_info->ra_pages,
1272 q->backing_dev_info->ra_pages);
1274 atomic_set(&dc->io_errors, 0);
1275 dc->io_disable = false;
1276 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1277 /* default to auto */
1278 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1280 bch_cached_dev_request_init(dc);
1281 bch_cached_dev_writeback_init(dc);
1285 /* Cached device - bcache superblock */
1287 static int register_bdev(struct cache_sb *sb, struct page *sb_page,
1288 struct block_device *bdev,
1289 struct cached_dev *dc)
1291 const char *err = "cannot allocate memory";
1292 struct cache_set *c;
1294 bdevname(bdev, dc->backing_dev_name);
1295 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1297 dc->bdev->bd_holder = dc;
1299 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1);
1300 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page;
1304 if (cached_dev_init(dc, sb->block_size << 9))
1307 err = "error creating kobject";
1308 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1311 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1314 pr_info("registered backing device %s", dc->backing_dev_name);
1316 list_add(&dc->list, &uncached_devices);
1317 /* attach to a matched cache set if it exists */
1318 list_for_each_entry(c, &bch_cache_sets, list)
1319 bch_cached_dev_attach(dc, c, NULL);
1321 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1322 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
1323 bch_cached_dev_run(dc);
1327 pr_notice("error %s: %s", dc->backing_dev_name, err);
1328 bcache_device_stop(&dc->disk);
1332 /* Flash only volumes */
1334 /* When d->kobj released */
1335 void bch_flash_dev_release(struct kobject *kobj)
1337 struct bcache_device *d = container_of(kobj, struct bcache_device,
1342 static void flash_dev_free(struct closure *cl)
1344 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1346 mutex_lock(&bch_register_lock);
1347 atomic_long_sub(bcache_dev_sectors_dirty(d),
1348 &d->c->flash_dev_dirty_sectors);
1349 bcache_device_free(d);
1350 mutex_unlock(&bch_register_lock);
1351 kobject_put(&d->kobj);
1354 static void flash_dev_flush(struct closure *cl)
1356 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1358 mutex_lock(&bch_register_lock);
1359 bcache_device_unlink(d);
1360 mutex_unlock(&bch_register_lock);
1361 kobject_del(&d->kobj);
1362 continue_at(cl, flash_dev_free, system_wq);
1365 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1367 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1372 closure_init(&d->cl, NULL);
1373 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1375 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1377 if (bcache_device_init(d, block_bytes(c), u->sectors))
1380 bcache_device_attach(d, c, u - c->uuids);
1381 bch_sectors_dirty_init(d);
1382 bch_flash_dev_request_init(d);
1385 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1388 bcache_device_link(d, c, "volume");
1392 kobject_put(&d->kobj);
1396 static int flash_devs_run(struct cache_set *c)
1399 struct uuid_entry *u;
1402 u < c->uuids + c->nr_uuids && !ret;
1404 if (UUID_FLASH_ONLY(u))
1405 ret = flash_dev_run(c, u);
1410 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1412 struct uuid_entry *u;
1414 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1417 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1420 u = uuid_find_empty(c);
1422 pr_err("Can't create volume, no room for UUID");
1426 get_random_bytes(u->uuid, 16);
1427 memset(u->label, 0, 32);
1428 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1430 SET_UUID_FLASH_ONLY(u, 1);
1431 u->sectors = size >> 9;
1435 return flash_dev_run(c, u);
1438 bool bch_cached_dev_error(struct cached_dev *dc)
1440 struct cache_set *c;
1442 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1445 dc->io_disable = true;
1446 /* make others know io_disable is true earlier */
1449 pr_err("stop %s: too many IO errors on backing device %s\n",
1450 dc->disk.disk->disk_name, dc->backing_dev_name);
1453 * If the cached device is still attached to a cache set,
1454 * even dc->io_disable is true and no more I/O requests
1455 * accepted, cache device internal I/O (writeback scan or
1456 * garbage collection) may still prevent bcache device from
1457 * being stopped. So here CACHE_SET_IO_DISABLE should be
1458 * set to c->flags too, to make the internal I/O to cache
1459 * device rejected and stopped immediately.
1460 * If c is NULL, that means the bcache device is not attached
1461 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set.
1464 if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1465 pr_info("CACHE_SET_IO_DISABLE already set");
1467 bcache_device_stop(&dc->disk);
1474 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1478 if (c->on_error != ON_ERROR_PANIC &&
1479 test_bit(CACHE_SET_STOPPING, &c->flags))
1482 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1483 pr_info("CACHE_SET_IO_DISABLE already set");
1486 * XXX: we can be called from atomic context
1487 * acquire_console_sem();
1490 pr_err("bcache: error on %pU: ", c->sb.set_uuid);
1492 va_start(args, fmt);
1496 pr_err(", disabling caching\n");
1498 if (c->on_error == ON_ERROR_PANIC)
1499 panic("panic forced after error\n");
1501 bch_cache_set_unregister(c);
1505 /* When c->kobj released */
1506 void bch_cache_set_release(struct kobject *kobj)
1508 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1511 module_put(THIS_MODULE);
1514 static void cache_set_free(struct closure *cl)
1516 struct cache_set *c = container_of(cl, struct cache_set, cl);
1520 debugfs_remove(c->debug);
1522 bch_open_buckets_free(c);
1523 bch_btree_cache_free(c);
1524 bch_journal_free(c);
1526 mutex_lock(&bch_register_lock);
1527 for_each_cache(ca, c, i)
1530 c->cache[ca->sb.nr_this_dev] = NULL;
1531 kobject_put(&ca->kobj);
1534 bch_bset_sort_state_free(&c->sort);
1535 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
1537 if (c->moving_gc_wq)
1538 destroy_workqueue(c->moving_gc_wq);
1539 bioset_exit(&c->bio_split);
1540 mempool_exit(&c->fill_iter);
1541 mempool_exit(&c->bio_meta);
1542 mempool_exit(&c->search);
1546 mutex_unlock(&bch_register_lock);
1548 pr_info("Cache set %pU unregistered", c->sb.set_uuid);
1549 wake_up(&unregister_wait);
1551 closure_debug_destroy(&c->cl);
1552 kobject_put(&c->kobj);
1555 static void cache_set_flush(struct closure *cl)
1557 struct cache_set *c = container_of(cl, struct cache_set, caching);
1562 bch_cache_accounting_destroy(&c->accounting);
1564 kobject_put(&c->internal);
1565 kobject_del(&c->kobj);
1568 kthread_stop(c->gc_thread);
1570 if (!IS_ERR_OR_NULL(c->root))
1571 list_add(&c->root->list, &c->btree_cache);
1573 /* Should skip this if we're unregistering because of an error */
1574 list_for_each_entry(b, &c->btree_cache, list) {
1575 mutex_lock(&b->write_lock);
1576 if (btree_node_dirty(b))
1577 __bch_btree_node_write(b, NULL);
1578 mutex_unlock(&b->write_lock);
1581 for_each_cache(ca, c, i)
1582 if (ca->alloc_thread)
1583 kthread_stop(ca->alloc_thread);
1585 if (c->journal.cur) {
1586 cancel_delayed_work_sync(&c->journal.work);
1587 /* flush last journal entry if needed */
1588 c->journal.work.work.func(&c->journal.work.work);
1595 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1596 * cache set is unregistering due to too many I/O errors. In this condition,
1597 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1598 * value and whether the broken cache has dirty data:
1600 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1601 * BCH_CACHED_STOP_AUTO 0 NO
1602 * BCH_CACHED_STOP_AUTO 1 YES
1603 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1604 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1606 * The expected behavior is, if stop_when_cache_set_failed is configured to
1607 * "auto" via sysfs interface, the bcache device will not be stopped if the
1608 * backing device is clean on the broken cache device.
1610 static void conditional_stop_bcache_device(struct cache_set *c,
1611 struct bcache_device *d,
1612 struct cached_dev *dc)
1614 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1615 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.",
1616 d->disk->disk_name, c->sb.set_uuid);
1617 bcache_device_stop(d);
1618 } else if (atomic_read(&dc->has_dirty)) {
1620 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1621 * and dc->has_dirty == 1
1623 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.",
1624 d->disk->disk_name);
1626 * There might be a small time gap that cache set is
1627 * released but bcache device is not. Inside this time
1628 * gap, regular I/O requests will directly go into
1629 * backing device as no cache set attached to. This
1630 * behavior may also introduce potential inconsistence
1631 * data in writeback mode while cache is dirty.
1632 * Therefore before calling bcache_device_stop() due
1633 * to a broken cache device, dc->io_disable should be
1634 * explicitly set to true.
1636 dc->io_disable = true;
1637 /* make others know io_disable is true earlier */
1639 bcache_device_stop(d);
1642 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1643 * and dc->has_dirty == 0
1645 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.",
1646 d->disk->disk_name);
1650 static void __cache_set_unregister(struct closure *cl)
1652 struct cache_set *c = container_of(cl, struct cache_set, caching);
1653 struct cached_dev *dc;
1654 struct bcache_device *d;
1657 mutex_lock(&bch_register_lock);
1659 for (i = 0; i < c->devices_max_used; i++) {
1664 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1665 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1666 dc = container_of(d, struct cached_dev, disk);
1667 bch_cached_dev_detach(dc);
1668 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1669 conditional_stop_bcache_device(c, d, dc);
1671 bcache_device_stop(d);
1675 mutex_unlock(&bch_register_lock);
1677 continue_at(cl, cache_set_flush, system_wq);
1680 void bch_cache_set_stop(struct cache_set *c)
1682 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1683 /* closure_fn set to __cache_set_unregister() */
1684 closure_queue(&c->caching);
1687 void bch_cache_set_unregister(struct cache_set *c)
1689 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1690 bch_cache_set_stop(c);
1693 #define alloc_bucket_pages(gfp, c) \
1694 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
1696 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1699 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1704 __module_get(THIS_MODULE);
1705 closure_init(&c->cl, NULL);
1706 set_closure_fn(&c->cl, cache_set_free, system_wq);
1708 closure_init(&c->caching, &c->cl);
1709 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1711 /* Maybe create continue_at_noreturn() and use it here? */
1712 closure_set_stopped(&c->cl);
1713 closure_put(&c->cl);
1715 kobject_init(&c->kobj, &bch_cache_set_ktype);
1716 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1718 bch_cache_accounting_init(&c->accounting, &c->cl);
1720 memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1721 c->sb.block_size = sb->block_size;
1722 c->sb.bucket_size = sb->bucket_size;
1723 c->sb.nr_in_set = sb->nr_in_set;
1724 c->sb.last_mount = sb->last_mount;
1725 c->bucket_bits = ilog2(sb->bucket_size);
1726 c->block_bits = ilog2(sb->block_size);
1727 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
1728 c->devices_max_used = 0;
1729 atomic_set(&c->attached_dev_nr, 0);
1730 c->btree_pages = bucket_pages(c);
1731 if (c->btree_pages > BTREE_MAX_PAGES)
1732 c->btree_pages = max_t(int, c->btree_pages / 4,
1735 sema_init(&c->sb_write_mutex, 1);
1736 mutex_init(&c->bucket_lock);
1737 init_waitqueue_head(&c->btree_cache_wait);
1738 init_waitqueue_head(&c->bucket_wait);
1739 init_waitqueue_head(&c->gc_wait);
1740 sema_init(&c->uuid_write_mutex, 1);
1742 spin_lock_init(&c->btree_gc_time.lock);
1743 spin_lock_init(&c->btree_split_time.lock);
1744 spin_lock_init(&c->btree_read_time.lock);
1746 bch_moving_init_cache_set(c);
1748 INIT_LIST_HEAD(&c->list);
1749 INIT_LIST_HEAD(&c->cached_devs);
1750 INIT_LIST_HEAD(&c->btree_cache);
1751 INIT_LIST_HEAD(&c->btree_cache_freeable);
1752 INIT_LIST_HEAD(&c->btree_cache_freed);
1753 INIT_LIST_HEAD(&c->data_buckets);
1755 iter_size = (sb->bucket_size / sb->block_size + 1) *
1756 sizeof(struct btree_iter_set);
1758 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) ||
1759 mempool_init_slab_pool(&c->search, 32, bch_search_cache) ||
1760 mempool_init_kmalloc_pool(&c->bio_meta, 2,
1761 sizeof(struct bbio) + sizeof(struct bio_vec) *
1763 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
1764 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1765 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) ||
1766 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
1767 !(c->moving_gc_wq = alloc_workqueue("bcache_gc",
1768 WQ_MEM_RECLAIM, 0)) ||
1769 bch_journal_alloc(c) ||
1770 bch_btree_cache_alloc(c) ||
1771 bch_open_buckets_alloc(c) ||
1772 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1775 c->congested_read_threshold_us = 2000;
1776 c->congested_write_threshold_us = 20000;
1777 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1778 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1782 bch_cache_set_unregister(c);
1786 static int run_cache_set(struct cache_set *c)
1788 const char *err = "cannot allocate memory";
1789 struct cached_dev *dc, *t;
1794 struct journal_replay *l;
1796 closure_init_stack(&cl);
1798 for_each_cache(ca, c, i)
1799 c->nbuckets += ca->sb.nbuckets;
1802 if (CACHE_SYNC(&c->sb)) {
1806 err = "cannot allocate memory for journal";
1807 if (bch_journal_read(c, &journal))
1810 pr_debug("btree_journal_read() done");
1812 err = "no journal entries found";
1813 if (list_empty(&journal))
1816 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1818 err = "IO error reading priorities";
1819 for_each_cache(ca, c, i)
1820 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]);
1823 * If prio_read() fails it'll call cache_set_error and we'll
1824 * tear everything down right away, but if we perhaps checked
1825 * sooner we could avoid journal replay.
1830 err = "bad btree root";
1831 if (__bch_btree_ptr_invalid(c, k))
1834 err = "error reading btree root";
1835 c->root = bch_btree_node_get(c, NULL, k,
1838 if (IS_ERR_OR_NULL(c->root))
1841 list_del_init(&c->root->list);
1842 rw_unlock(true, c->root);
1844 err = uuid_read(c, j, &cl);
1848 err = "error in recovery";
1849 if (bch_btree_check(c))
1852 bch_journal_mark(c, &journal);
1853 bch_initial_gc_finish(c);
1854 pr_debug("btree_check() done");
1857 * bcache_journal_next() can't happen sooner, or
1858 * btree_gc_finish() will give spurious errors about last_gc >
1859 * gc_gen - this is a hack but oh well.
1861 bch_journal_next(&c->journal);
1863 err = "error starting allocator thread";
1864 for_each_cache(ca, c, i)
1865 if (bch_cache_allocator_start(ca))
1869 * First place it's safe to allocate: btree_check() and
1870 * btree_gc_finish() have to run before we have buckets to
1871 * allocate, and bch_bucket_alloc_set() might cause a journal
1872 * entry to be written so bcache_journal_next() has to be called
1875 * If the uuids were in the old format we have to rewrite them
1876 * before the next journal entry is written:
1878 if (j->version < BCACHE_JSET_VERSION_UUID)
1881 err = "bcache: replay journal failed";
1882 if (bch_journal_replay(c, &journal))
1885 pr_notice("invalidating existing data");
1887 for_each_cache(ca, c, i) {
1890 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
1891 2, SB_JOURNAL_BUCKETS);
1893 for (j = 0; j < ca->sb.keys; j++)
1894 ca->sb.d[j] = ca->sb.first_bucket + j;
1897 bch_initial_gc_finish(c);
1899 err = "error starting allocator thread";
1900 for_each_cache(ca, c, i)
1901 if (bch_cache_allocator_start(ca))
1904 mutex_lock(&c->bucket_lock);
1905 for_each_cache(ca, c, i)
1907 mutex_unlock(&c->bucket_lock);
1909 err = "cannot allocate new UUID bucket";
1910 if (__uuid_write(c))
1913 err = "cannot allocate new btree root";
1914 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
1915 if (IS_ERR_OR_NULL(c->root))
1918 mutex_lock(&c->root->write_lock);
1919 bkey_copy_key(&c->root->key, &MAX_KEY);
1920 bch_btree_node_write(c->root, &cl);
1921 mutex_unlock(&c->root->write_lock);
1923 bch_btree_set_root(c->root);
1924 rw_unlock(true, c->root);
1927 * We don't want to write the first journal entry until
1928 * everything is set up - fortunately journal entries won't be
1929 * written until the SET_CACHE_SYNC() here:
1931 SET_CACHE_SYNC(&c->sb, true);
1933 bch_journal_next(&c->journal);
1934 bch_journal_meta(c, &cl);
1937 err = "error starting gc thread";
1938 if (bch_gc_thread_start(c))
1942 c->sb.last_mount = (u32)ktime_get_real_seconds();
1943 bcache_write_super(c);
1945 list_for_each_entry_safe(dc, t, &uncached_devices, list)
1946 bch_cached_dev_attach(dc, c, NULL);
1950 set_bit(CACHE_SET_RUNNING, &c->flags);
1953 while (!list_empty(&journal)) {
1954 l = list_first_entry(&journal, struct journal_replay, list);
1960 /* XXX: test this, it's broken */
1961 bch_cache_set_error(c, "%s", err);
1966 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
1968 return ca->sb.block_size == c->sb.block_size &&
1969 ca->sb.bucket_size == c->sb.bucket_size &&
1970 ca->sb.nr_in_set == c->sb.nr_in_set;
1973 static const char *register_cache_set(struct cache *ca)
1976 const char *err = "cannot allocate memory";
1977 struct cache_set *c;
1979 list_for_each_entry(c, &bch_cache_sets, list)
1980 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
1981 if (c->cache[ca->sb.nr_this_dev])
1982 return "duplicate cache set member";
1984 if (!can_attach_cache(ca, c))
1985 return "cache sb does not match set";
1987 if (!CACHE_SYNC(&ca->sb))
1988 SET_CACHE_SYNC(&c->sb, false);
1993 c = bch_cache_set_alloc(&ca->sb);
1997 err = "error creating kobject";
1998 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
1999 kobject_add(&c->internal, &c->kobj, "internal"))
2002 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2005 bch_debug_init_cache_set(c);
2007 list_add(&c->list, &bch_cache_sets);
2009 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2010 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2011 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2014 if (ca->sb.seq > c->sb.seq) {
2015 c->sb.version = ca->sb.version;
2016 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2017 c->sb.flags = ca->sb.flags;
2018 c->sb.seq = ca->sb.seq;
2019 pr_debug("set version = %llu", c->sb.version);
2022 kobject_get(&ca->kobj);
2024 ca->set->cache[ca->sb.nr_this_dev] = ca;
2025 c->cache_by_alloc[c->caches_loaded++] = ca;
2027 if (c->caches_loaded == c->sb.nr_in_set) {
2028 err = "failed to run cache set";
2029 if (run_cache_set(c) < 0)
2035 bch_cache_set_unregister(c);
2041 /* When ca->kobj released */
2042 void bch_cache_release(struct kobject *kobj)
2044 struct cache *ca = container_of(kobj, struct cache, kobj);
2048 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca);
2049 ca->set->cache[ca->sb.nr_this_dev] = NULL;
2052 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
2053 kfree(ca->prio_buckets);
2056 free_heap(&ca->heap);
2057 free_fifo(&ca->free_inc);
2059 for (i = 0; i < RESERVE_NR; i++)
2060 free_fifo(&ca->free[i]);
2062 if (ca->sb_bio.bi_inline_vecs[0].bv_page)
2063 put_page(bio_first_page_all(&ca->sb_bio));
2065 if (!IS_ERR_OR_NULL(ca->bdev))
2066 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2069 module_put(THIS_MODULE);
2072 static int cache_alloc(struct cache *ca)
2075 size_t btree_buckets;
2078 const char *err = NULL;
2080 __module_get(THIS_MODULE);
2081 kobject_init(&ca->kobj, &bch_cache_ktype);
2083 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2086 * when ca->sb.njournal_buckets is not zero, journal exists,
2087 * and in bch_journal_replay(), tree node may split,
2088 * so bucket of RESERVE_BTREE type is needed,
2089 * the worst situation is all journal buckets are valid journal,
2090 * and all the keys need to replay,
2091 * so the number of RESERVE_BTREE type buckets should be as much
2092 * as journal buckets
2094 btree_buckets = ca->sb.njournal_buckets ?: 8;
2095 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2098 err = "ca->sb.nbuckets is too small";
2102 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2104 err = "ca->free[RESERVE_BTREE] alloc failed";
2105 goto err_btree_alloc;
2108 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2110 err = "ca->free[RESERVE_PRIO] alloc failed";
2111 goto err_prio_alloc;
2114 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2115 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2116 goto err_movinggc_alloc;
2119 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2120 err = "ca->free[RESERVE_NONE] alloc failed";
2121 goto err_none_alloc;
2124 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2125 err = "ca->free_inc alloc failed";
2126 goto err_free_inc_alloc;
2129 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2130 err = "ca->heap alloc failed";
2131 goto err_heap_alloc;
2134 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2137 err = "ca->buckets alloc failed";
2138 goto err_buckets_alloc;
2141 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2142 prio_buckets(ca), 2),
2144 if (!ca->prio_buckets) {
2145 err = "ca->prio_buckets alloc failed";
2146 goto err_prio_buckets_alloc;
2149 ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca);
2150 if (!ca->disk_buckets) {
2151 err = "ca->disk_buckets alloc failed";
2152 goto err_disk_buckets_alloc;
2155 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2157 for_each_bucket(b, ca)
2158 atomic_set(&b->pin, 0);
2161 err_disk_buckets_alloc:
2162 kfree(ca->prio_buckets);
2163 err_prio_buckets_alloc:
2166 free_heap(&ca->heap);
2168 free_fifo(&ca->free_inc);
2170 free_fifo(&ca->free[RESERVE_NONE]);
2172 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2174 free_fifo(&ca->free[RESERVE_PRIO]);
2176 free_fifo(&ca->free[RESERVE_BTREE]);
2179 module_put(THIS_MODULE);
2181 pr_notice("error %s: %s", ca->cache_dev_name, err);
2185 static int register_cache(struct cache_sb *sb, struct page *sb_page,
2186 struct block_device *bdev, struct cache *ca)
2188 const char *err = NULL; /* must be set for any error case */
2191 bdevname(bdev, ca->cache_dev_name);
2192 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2194 ca->bdev->bd_holder = ca;
2196 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1);
2197 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page;
2200 if (blk_queue_discard(bdev_get_queue(bdev)))
2201 ca->discard = CACHE_DISCARD(&ca->sb);
2203 ret = cache_alloc(ca);
2206 * If we failed here, it means ca->kobj is not initialized yet,
2207 * kobject_put() won't be called and there is no chance to
2208 * call blkdev_put() to bdev in bch_cache_release(). So we
2209 * explicitly call blkdev_put() here.
2211 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2213 err = "cache_alloc(): -ENOMEM";
2214 else if (ret == -EPERM)
2215 err = "cache_alloc(): cache device is too small";
2217 err = "cache_alloc(): unknown error";
2221 if (kobject_add(&ca->kobj,
2222 &part_to_dev(bdev->bd_part)->kobj,
2224 err = "error calling kobject_add";
2229 mutex_lock(&bch_register_lock);
2230 err = register_cache_set(ca);
2231 mutex_unlock(&bch_register_lock);
2238 pr_info("registered cache device %s", ca->cache_dev_name);
2241 kobject_put(&ca->kobj);
2245 pr_notice("error %s: %s", ca->cache_dev_name, err);
2250 /* Global interfaces/init */
2252 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2253 const char *buffer, size_t size);
2255 kobj_attribute_write(register, register_bcache);
2256 kobj_attribute_write(register_quiet, register_bcache);
2258 static bool bch_is_open_backing(struct block_device *bdev)
2260 struct cache_set *c, *tc;
2261 struct cached_dev *dc, *t;
2263 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2264 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2265 if (dc->bdev == bdev)
2267 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2268 if (dc->bdev == bdev)
2273 static bool bch_is_open_cache(struct block_device *bdev)
2275 struct cache_set *c, *tc;
2279 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2280 for_each_cache(ca, c, i)
2281 if (ca->bdev == bdev)
2286 static bool bch_is_open(struct block_device *bdev)
2288 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
2291 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2292 const char *buffer, size_t size)
2294 ssize_t ret = -EINVAL;
2295 const char *err = "cannot allocate memory";
2297 struct cache_sb *sb = NULL;
2298 struct block_device *bdev = NULL;
2299 struct page *sb_page = NULL;
2301 if (!try_module_get(THIS_MODULE))
2304 path = kstrndup(buffer, size, GFP_KERNEL);
2308 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2312 err = "failed to open device";
2313 bdev = blkdev_get_by_path(strim(path),
2314 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2317 if (bdev == ERR_PTR(-EBUSY)) {
2318 bdev = lookup_bdev(strim(path));
2319 mutex_lock(&bch_register_lock);
2320 if (!IS_ERR(bdev) && bch_is_open(bdev))
2321 err = "device already registered";
2323 err = "device busy";
2324 mutex_unlock(&bch_register_lock);
2327 if (attr == &ksysfs_register_quiet)
2333 err = "failed to set blocksize";
2334 if (set_blocksize(bdev, 4096))
2337 err = read_super(sb, bdev, &sb_page);
2341 err = "failed to register device";
2342 if (SB_IS_BDEV(sb)) {
2343 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2348 mutex_lock(&bch_register_lock);
2349 ret = register_bdev(sb, sb_page, bdev, dc);
2350 mutex_unlock(&bch_register_lock);
2351 /* blkdev_put() will be called in cached_dev_free() */
2355 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2360 /* blkdev_put() will be called in bch_cache_release() */
2361 if (register_cache(sb, sb_page, bdev, ca) != 0)
2371 module_put(THIS_MODULE);
2375 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2377 pr_info("error %s: %s", path, err);
2381 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2383 if (code == SYS_DOWN ||
2385 code == SYS_POWER_OFF) {
2387 unsigned long start = jiffies;
2388 bool stopped = false;
2390 struct cache_set *c, *tc;
2391 struct cached_dev *dc, *tdc;
2393 mutex_lock(&bch_register_lock);
2395 if (list_empty(&bch_cache_sets) &&
2396 list_empty(&uncached_devices))
2399 pr_info("Stopping all devices:");
2401 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2402 bch_cache_set_stop(c);
2404 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2405 bcache_device_stop(&dc->disk);
2407 mutex_unlock(&bch_register_lock);
2410 * Give an early chance for other kthreads and
2411 * kworkers to stop themselves
2415 /* What's a condition variable? */
2417 long timeout = start + 10 * HZ - jiffies;
2419 mutex_lock(&bch_register_lock);
2420 stopped = list_empty(&bch_cache_sets) &&
2421 list_empty(&uncached_devices);
2423 if (timeout < 0 || stopped)
2426 prepare_to_wait(&unregister_wait, &wait,
2427 TASK_UNINTERRUPTIBLE);
2429 mutex_unlock(&bch_register_lock);
2430 schedule_timeout(timeout);
2433 finish_wait(&unregister_wait, &wait);
2436 pr_info("All devices stopped");
2438 pr_notice("Timeout waiting for devices to be closed");
2440 mutex_unlock(&bch_register_lock);
2446 static struct notifier_block reboot = {
2447 .notifier_call = bcache_reboot,
2448 .priority = INT_MAX, /* before any real devices */
2451 static void bcache_exit(void)
2456 kobject_put(bcache_kobj);
2458 destroy_workqueue(bcache_wq);
2460 destroy_workqueue(bch_journal_wq);
2463 unregister_blkdev(bcache_major, "bcache");
2464 unregister_reboot_notifier(&reboot);
2465 mutex_destroy(&bch_register_lock);
2468 /* Check and fixup module parameters */
2469 static void check_module_parameters(void)
2471 if (bch_cutoff_writeback_sync == 0)
2472 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2473 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2474 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u",
2475 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2476 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2479 if (bch_cutoff_writeback == 0)
2480 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2481 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2482 pr_warn("set bch_cutoff_writeback (%u) to max value %u",
2483 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2484 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2487 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2488 pr_warn("set bch_cutoff_writeback (%u) to %u",
2489 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2490 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2494 static int __init bcache_init(void)
2496 static const struct attribute *files[] = {
2497 &ksysfs_register.attr,
2498 &ksysfs_register_quiet.attr,
2502 check_module_parameters();
2504 mutex_init(&bch_register_lock);
2505 init_waitqueue_head(&unregister_wait);
2506 register_reboot_notifier(&reboot);
2508 bcache_major = register_blkdev(0, "bcache");
2509 if (bcache_major < 0) {
2510 unregister_reboot_notifier(&reboot);
2511 mutex_destroy(&bch_register_lock);
2512 return bcache_major;
2515 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2519 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2520 if (!bch_journal_wq)
2523 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2527 if (bch_request_init() ||
2528 sysfs_create_files(bcache_kobj, files))
2532 closure_debug_init();
2543 module_exit(bcache_exit);
2544 module_init(bcache_init);
2546 module_param(bch_cutoff_writeback, uint, 0);
2547 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2549 module_param(bch_cutoff_writeback_sync, uint, 0);
2550 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2552 MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2553 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2554 MODULE_LICENSE("GPL");