2 * bcache setup/teardown code, and some metadata io - read a superblock and
3 * figure out what to do with it.
5 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
6 * Copyright 2012 Google, Inc.
14 #include "writeback.h"
16 #include <linux/blkdev.h>
17 #include <linux/buffer_head.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>
27 MODULE_LICENSE("GPL");
28 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
30 static const char bcache_magic[] = {
31 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
32 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
35 static const char invalid_uuid[] = {
36 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
37 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
40 /* Default is -1; we skip past it for struct cached_dev's cache mode */
41 const char * const bch_cache_modes[] = {
50 /* Default is -1; we skip past it for stop_when_cache_set_failed */
51 const char * const bch_stop_on_failure_modes[] = {
58 static struct kobject *bcache_kobj;
59 struct mutex bch_register_lock;
60 LIST_HEAD(bch_cache_sets);
61 static LIST_HEAD(uncached_devices);
63 static int bcache_major;
64 static DEFINE_IDA(bcache_device_idx);
65 static wait_queue_head_t unregister_wait;
66 struct workqueue_struct *bcache_wq;
68 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
69 /* limitation of partitions number on single bcache device */
70 #define BCACHE_MINORS 128
71 /* limitation of bcache devices number on single system */
72 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
76 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
81 struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
87 s = (struct cache_sb *) bh->b_data;
89 sb->offset = le64_to_cpu(s->offset);
90 sb->version = le64_to_cpu(s->version);
92 memcpy(sb->magic, s->magic, 16);
93 memcpy(sb->uuid, s->uuid, 16);
94 memcpy(sb->set_uuid, s->set_uuid, 16);
95 memcpy(sb->label, s->label, SB_LABEL_SIZE);
97 sb->flags = le64_to_cpu(s->flags);
98 sb->seq = le64_to_cpu(s->seq);
99 sb->last_mount = le32_to_cpu(s->last_mount);
100 sb->first_bucket = le16_to_cpu(s->first_bucket);
101 sb->keys = le16_to_cpu(s->keys);
103 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
104 sb->d[i] = le64_to_cpu(s->d[i]);
106 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
107 sb->version, sb->flags, sb->seq, sb->keys);
109 err = "Not a bcache superblock";
110 if (sb->offset != SB_SECTOR)
113 if (memcmp(sb->magic, bcache_magic, 16))
116 err = "Too many journal buckets";
117 if (sb->keys > SB_JOURNAL_BUCKETS)
120 err = "Bad checksum";
121 if (s->csum != csum_set(s))
125 if (bch_is_zero(sb->uuid, 16))
128 sb->block_size = le16_to_cpu(s->block_size);
130 err = "Superblock block size smaller than device block size";
131 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
134 switch (sb->version) {
135 case BCACHE_SB_VERSION_BDEV:
136 sb->data_offset = BDEV_DATA_START_DEFAULT;
138 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
139 sb->data_offset = le64_to_cpu(s->data_offset);
141 err = "Bad data offset";
142 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
146 case BCACHE_SB_VERSION_CDEV:
147 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
148 sb->nbuckets = le64_to_cpu(s->nbuckets);
149 sb->bucket_size = le16_to_cpu(s->bucket_size);
151 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
152 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
154 err = "Too many buckets";
155 if (sb->nbuckets > LONG_MAX)
158 err = "Not enough buckets";
159 if (sb->nbuckets < 1 << 7)
162 err = "Bad block/bucket size";
163 if (!is_power_of_2(sb->block_size) ||
164 sb->block_size > PAGE_SECTORS ||
165 !is_power_of_2(sb->bucket_size) ||
166 sb->bucket_size < PAGE_SECTORS)
169 err = "Invalid superblock: device too small";
170 if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets)
174 if (bch_is_zero(sb->set_uuid, 16))
177 err = "Bad cache device number in set";
178 if (!sb->nr_in_set ||
179 sb->nr_in_set <= sb->nr_this_dev ||
180 sb->nr_in_set > MAX_CACHES_PER_SET)
183 err = "Journal buckets not sequential";
184 for (i = 0; i < sb->keys; i++)
185 if (sb->d[i] != sb->first_bucket + i)
188 err = "Too many journal buckets";
189 if (sb->first_bucket + sb->keys > sb->nbuckets)
192 err = "Invalid superblock: first bucket comes before end of super";
193 if (sb->first_bucket * sb->bucket_size < 16)
198 err = "Unsupported superblock version";
202 sb->last_mount = get_seconds();
205 get_page(bh->b_page);
212 static void write_bdev_super_endio(struct bio *bio)
214 struct cached_dev *dc = bio->bi_private;
215 /* XXX: error checking */
217 closure_put(&dc->sb_write);
220 static void __write_super(struct cache_sb *sb, struct bio *bio)
222 struct cache_sb *out = page_address(bio_first_page_all(bio));
225 bio->bi_iter.bi_sector = SB_SECTOR;
226 bio->bi_iter.bi_size = SB_SIZE;
227 bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META);
228 bch_bio_map(bio, NULL);
230 out->offset = cpu_to_le64(sb->offset);
231 out->version = cpu_to_le64(sb->version);
233 memcpy(out->uuid, sb->uuid, 16);
234 memcpy(out->set_uuid, sb->set_uuid, 16);
235 memcpy(out->label, sb->label, SB_LABEL_SIZE);
237 out->flags = cpu_to_le64(sb->flags);
238 out->seq = cpu_to_le64(sb->seq);
240 out->last_mount = cpu_to_le32(sb->last_mount);
241 out->first_bucket = cpu_to_le16(sb->first_bucket);
242 out->keys = cpu_to_le16(sb->keys);
244 for (i = 0; i < sb->keys; i++)
245 out->d[i] = cpu_to_le64(sb->d[i]);
247 out->csum = csum_set(out);
249 pr_debug("ver %llu, flags %llu, seq %llu",
250 sb->version, sb->flags, sb->seq);
255 static void bch_write_bdev_super_unlock(struct closure *cl)
257 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
259 up(&dc->sb_write_mutex);
262 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
264 struct closure *cl = &dc->sb_write;
265 struct bio *bio = &dc->sb_bio;
267 down(&dc->sb_write_mutex);
268 closure_init(cl, parent);
271 bio_set_dev(bio, dc->bdev);
272 bio->bi_end_io = write_bdev_super_endio;
273 bio->bi_private = dc;
276 __write_super(&dc->sb, bio);
278 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
281 static void write_super_endio(struct bio *bio)
283 struct cache *ca = bio->bi_private;
286 bch_count_io_errors(ca, bio->bi_status, 0,
287 "writing superblock");
288 closure_put(&ca->set->sb_write);
291 static void bcache_write_super_unlock(struct closure *cl)
293 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
295 up(&c->sb_write_mutex);
298 void bcache_write_super(struct cache_set *c)
300 struct closure *cl = &c->sb_write;
304 down(&c->sb_write_mutex);
305 closure_init(cl, &c->cl);
309 for_each_cache(ca, c, i) {
310 struct bio *bio = &ca->sb_bio;
312 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
313 ca->sb.seq = c->sb.seq;
314 ca->sb.last_mount = c->sb.last_mount;
316 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
319 bio_set_dev(bio, ca->bdev);
320 bio->bi_end_io = write_super_endio;
321 bio->bi_private = ca;
324 __write_super(&ca->sb, bio);
327 closure_return_with_destructor(cl, bcache_write_super_unlock);
332 static void uuid_endio(struct bio *bio)
334 struct closure *cl = bio->bi_private;
335 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
337 cache_set_err_on(bio->bi_status, c, "accessing uuids");
338 bch_bbio_free(bio, c);
342 static void uuid_io_unlock(struct closure *cl)
344 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
346 up(&c->uuid_write_mutex);
349 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
350 struct bkey *k, struct closure *parent)
352 struct closure *cl = &c->uuid_write;
353 struct uuid_entry *u;
358 down(&c->uuid_write_mutex);
359 closure_init(cl, parent);
361 for (i = 0; i < KEY_PTRS(k); i++) {
362 struct bio *bio = bch_bbio_alloc(c);
364 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
365 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
367 bio->bi_end_io = uuid_endio;
368 bio->bi_private = cl;
369 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
370 bch_bio_map(bio, c->uuids);
372 bch_submit_bbio(bio, c, k, i);
374 if (op != REQ_OP_WRITE)
378 bch_extent_to_text(buf, sizeof(buf), k);
379 pr_debug("%s UUIDs at %s", op == REQ_OP_WRITE ? "wrote" : "read", buf);
381 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
382 if (!bch_is_zero(u->uuid, 16))
383 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
384 u - c->uuids, u->uuid, u->label,
385 u->first_reg, u->last_reg, u->invalidated);
387 closure_return_with_destructor(cl, uuid_io_unlock);
390 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
392 struct bkey *k = &j->uuid_bucket;
394 if (__bch_btree_ptr_invalid(c, k))
395 return "bad uuid pointer";
397 bkey_copy(&c->uuid_bucket, k);
398 uuid_io(c, REQ_OP_READ, 0, k, cl);
400 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
401 struct uuid_entry_v0 *u0 = (void *) c->uuids;
402 struct uuid_entry *u1 = (void *) c->uuids;
408 * Since the new uuid entry is bigger than the old, we have to
409 * convert starting at the highest memory address and work down
410 * in order to do it in place
413 for (i = c->nr_uuids - 1;
416 memcpy(u1[i].uuid, u0[i].uuid, 16);
417 memcpy(u1[i].label, u0[i].label, 32);
419 u1[i].first_reg = u0[i].first_reg;
420 u1[i].last_reg = u0[i].last_reg;
421 u1[i].invalidated = u0[i].invalidated;
431 static int __uuid_write(struct cache_set *c)
435 closure_init_stack(&cl);
437 lockdep_assert_held(&bch_register_lock);
439 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
442 SET_KEY_SIZE(&k.key, c->sb.bucket_size);
443 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
446 bkey_copy(&c->uuid_bucket, &k.key);
451 int bch_uuid_write(struct cache_set *c)
453 int ret = __uuid_write(c);
456 bch_journal_meta(c, NULL);
461 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
463 struct uuid_entry *u;
466 u < c->uuids + c->nr_uuids; u++)
467 if (!memcmp(u->uuid, uuid, 16))
473 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
475 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
476 return uuid_find(c, zero_uuid);
480 * Bucket priorities/gens:
482 * For each bucket, we store on disk its
486 * See alloc.c for an explanation of the gen. The priority is used to implement
487 * lru (and in the future other) cache replacement policies; for most purposes
488 * it's just an opaque integer.
490 * The gens and the priorities don't have a whole lot to do with each other, and
491 * it's actually the gens that must be written out at specific times - it's no
492 * big deal if the priorities don't get written, if we lose them we just reuse
493 * buckets in suboptimal order.
495 * On disk they're stored in a packed array, and in as many buckets are required
496 * to fit them all. The buckets we use to store them form a list; the journal
497 * header points to the first bucket, the first bucket points to the second
500 * This code is used by the allocation code; periodically (whenever it runs out
501 * of buckets to allocate from) the allocation code will invalidate some
502 * buckets, but it can't use those buckets until their new gens are safely on
506 static void prio_endio(struct bio *bio)
508 struct cache *ca = bio->bi_private;
510 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
511 bch_bbio_free(bio, ca->set);
512 closure_put(&ca->prio);
515 static void prio_io(struct cache *ca, uint64_t bucket, int op,
516 unsigned long op_flags)
518 struct closure *cl = &ca->prio;
519 struct bio *bio = bch_bbio_alloc(ca->set);
521 closure_init_stack(cl);
523 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
524 bio_set_dev(bio, ca->bdev);
525 bio->bi_iter.bi_size = bucket_bytes(ca);
527 bio->bi_end_io = prio_endio;
528 bio->bi_private = ca;
529 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
530 bch_bio_map(bio, ca->disk_buckets);
532 closure_bio_submit(ca->set, bio, &ca->prio);
536 void bch_prio_write(struct cache *ca)
542 closure_init_stack(&cl);
544 lockdep_assert_held(&ca->set->bucket_lock);
546 ca->disk_buckets->seq++;
548 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
549 &ca->meta_sectors_written);
551 //pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free),
552 // fifo_used(&ca->free_inc), fifo_used(&ca->unused));
554 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
556 struct prio_set *p = ca->disk_buckets;
557 struct bucket_disk *d = p->data;
558 struct bucket_disk *end = d + prios_per_bucket(ca);
560 for (b = ca->buckets + i * prios_per_bucket(ca);
561 b < ca->buckets + ca->sb.nbuckets && d < end;
563 d->prio = cpu_to_le16(b->prio);
567 p->next_bucket = ca->prio_buckets[i + 1];
568 p->magic = pset_magic(&ca->sb);
569 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
571 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, true);
572 BUG_ON(bucket == -1);
574 mutex_unlock(&ca->set->bucket_lock);
575 prio_io(ca, bucket, REQ_OP_WRITE, 0);
576 mutex_lock(&ca->set->bucket_lock);
578 ca->prio_buckets[i] = bucket;
579 atomic_dec_bug(&ca->buckets[bucket].pin);
582 mutex_unlock(&ca->set->bucket_lock);
584 bch_journal_meta(ca->set, &cl);
587 mutex_lock(&ca->set->bucket_lock);
590 * Don't want the old priorities to get garbage collected until after we
591 * finish writing the new ones, and they're journalled
593 for (i = 0; i < prio_buckets(ca); i++) {
594 if (ca->prio_last_buckets[i])
595 __bch_bucket_free(ca,
596 &ca->buckets[ca->prio_last_buckets[i]]);
598 ca->prio_last_buckets[i] = ca->prio_buckets[i];
602 static void prio_read(struct cache *ca, uint64_t bucket)
604 struct prio_set *p = ca->disk_buckets;
605 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
607 unsigned bucket_nr = 0;
609 for (b = ca->buckets;
610 b < ca->buckets + ca->sb.nbuckets;
613 ca->prio_buckets[bucket_nr] = bucket;
614 ca->prio_last_buckets[bucket_nr] = bucket;
617 prio_io(ca, bucket, REQ_OP_READ, 0);
619 if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8))
620 pr_warn("bad csum reading priorities");
622 if (p->magic != pset_magic(&ca->sb))
623 pr_warn("bad magic reading priorities");
625 bucket = p->next_bucket;
629 b->prio = le16_to_cpu(d->prio);
630 b->gen = b->last_gc = d->gen;
636 static int open_dev(struct block_device *b, fmode_t mode)
638 struct bcache_device *d = b->bd_disk->private_data;
639 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
646 static void release_dev(struct gendisk *b, fmode_t mode)
648 struct bcache_device *d = b->private_data;
652 static int ioctl_dev(struct block_device *b, fmode_t mode,
653 unsigned int cmd, unsigned long arg)
655 struct bcache_device *d = b->bd_disk->private_data;
656 return d->ioctl(d, mode, cmd, arg);
659 static const struct block_device_operations bcache_ops = {
661 .release = release_dev,
663 .owner = THIS_MODULE,
666 void bcache_device_stop(struct bcache_device *d)
668 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
669 closure_queue(&d->cl);
672 static void bcache_device_unlink(struct bcache_device *d)
674 lockdep_assert_held(&bch_register_lock);
676 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
680 sysfs_remove_link(&d->c->kobj, d->name);
681 sysfs_remove_link(&d->kobj, "cache");
683 for_each_cache(ca, d->c, i)
684 bd_unlink_disk_holder(ca->bdev, d->disk);
688 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
694 for_each_cache(ca, d->c, i)
695 bd_link_disk_holder(ca->bdev, d->disk);
697 snprintf(d->name, BCACHEDEVNAME_SIZE,
698 "%s%u", name, d->id);
700 WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
701 sysfs_create_link(&c->kobj, &d->kobj, d->name),
702 "Couldn't create device <-> cache set symlinks");
704 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
707 static void bcache_device_detach(struct bcache_device *d)
709 lockdep_assert_held(&bch_register_lock);
711 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
712 struct uuid_entry *u = d->c->uuids + d->id;
714 SET_UUID_FLASH_ONLY(u, 0);
715 memcpy(u->uuid, invalid_uuid, 16);
716 u->invalidated = cpu_to_le32(get_seconds());
717 bch_uuid_write(d->c);
720 bcache_device_unlink(d);
722 d->c->devices[d->id] = NULL;
723 closure_put(&d->c->caching);
727 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
734 if (id >= c->devices_max_used)
735 c->devices_max_used = id + 1;
737 closure_get(&c->caching);
740 static inline int first_minor_to_idx(int first_minor)
742 return (first_minor/BCACHE_MINORS);
745 static inline int idx_to_first_minor(int idx)
747 return (idx * BCACHE_MINORS);
750 static void bcache_device_free(struct bcache_device *d)
752 lockdep_assert_held(&bch_register_lock);
754 pr_info("%s stopped", d->disk->disk_name);
757 bcache_device_detach(d);
758 if (d->disk && d->disk->flags & GENHD_FL_UP)
759 del_gendisk(d->disk);
760 if (d->disk && d->disk->queue)
761 blk_cleanup_queue(d->disk->queue);
763 ida_simple_remove(&bcache_device_idx,
764 first_minor_to_idx(d->disk->first_minor));
769 bioset_free(d->bio_split);
770 kvfree(d->full_dirty_stripes);
771 kvfree(d->stripe_sectors_dirty);
773 closure_debug_destroy(&d->cl);
776 static int bcache_device_init(struct bcache_device *d, unsigned block_size,
779 struct request_queue *q;
784 d->stripe_size = 1 << 31;
786 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
788 if (!d->nr_stripes ||
789 d->nr_stripes > INT_MAX ||
790 d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) {
791 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)",
792 (unsigned)d->nr_stripes);
796 n = d->nr_stripes * sizeof(atomic_t);
797 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
798 if (!d->stripe_sectors_dirty)
801 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
802 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
803 if (!d->full_dirty_stripes)
806 idx = ida_simple_get(&bcache_device_idx, 0,
807 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
811 if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio),
813 BIOSET_NEED_RESCUER)) ||
814 !(d->disk = alloc_disk(BCACHE_MINORS))) {
815 ida_simple_remove(&bcache_device_idx, idx);
819 set_capacity(d->disk, sectors);
820 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
822 d->disk->major = bcache_major;
823 d->disk->first_minor = idx_to_first_minor(idx);
824 d->disk->fops = &bcache_ops;
825 d->disk->private_data = d;
827 q = blk_alloc_queue(GFP_KERNEL);
831 blk_queue_make_request(q, NULL);
834 q->backing_dev_info->congested_data = d;
835 q->limits.max_hw_sectors = UINT_MAX;
836 q->limits.max_sectors = UINT_MAX;
837 q->limits.max_segment_size = UINT_MAX;
838 q->limits.max_segments = BIO_MAX_PAGES;
839 blk_queue_max_discard_sectors(q, UINT_MAX);
840 q->limits.discard_granularity = 512;
841 q->limits.io_min = block_size;
842 q->limits.logical_block_size = block_size;
843 q->limits.physical_block_size = block_size;
844 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
845 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
846 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
848 blk_queue_write_cache(q, true, true);
855 static void calc_cached_dev_sectors(struct cache_set *c)
857 uint64_t sectors = 0;
858 struct cached_dev *dc;
860 list_for_each_entry(dc, &c->cached_devs, list)
861 sectors += bdev_sectors(dc->bdev);
863 c->cached_dev_sectors = sectors;
866 void bch_cached_dev_run(struct cached_dev *dc)
868 struct bcache_device *d = &dc->disk;
869 char buf[SB_LABEL_SIZE + 1];
872 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
877 memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
878 buf[SB_LABEL_SIZE] = '\0';
879 env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf);
881 if (atomic_xchg(&dc->running, 1)) {
888 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
890 closure_init_stack(&cl);
892 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
893 bch_write_bdev_super(dc, &cl);
898 bd_link_disk_holder(dc->bdev, dc->disk.disk);
899 /* won't show up in the uevent file, use udevadm monitor -e instead
900 * only class / kset properties are persistent */
901 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
905 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
906 sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
907 pr_debug("error creating sysfs link");
911 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
912 * work dc->writeback_rate_update is running. Wait until the routine
913 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
914 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
915 * seconds, give up waiting here and continue to cancel it too.
917 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
919 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
922 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
926 schedule_timeout_interruptible(1);
927 } while (time_out > 0);
930 pr_warn("give up waiting for dc->writeback_write_update to quit");
932 cancel_delayed_work_sync(&dc->writeback_rate_update);
935 static void cached_dev_detach_finish(struct work_struct *w)
937 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
938 char buf[BDEVNAME_SIZE];
940 closure_init_stack(&cl);
942 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
943 BUG_ON(refcount_read(&dc->count));
945 mutex_lock(&bch_register_lock);
947 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
948 cancel_writeback_rate_update_dwork(dc);
950 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
951 kthread_stop(dc->writeback_thread);
952 dc->writeback_thread = NULL;
955 memset(&dc->sb.set_uuid, 0, 16);
956 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
958 bch_write_bdev_super(dc, &cl);
961 bcache_device_detach(&dc->disk);
962 list_move(&dc->list, &uncached_devices);
964 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
965 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
967 mutex_unlock(&bch_register_lock);
969 pr_info("Caching disabled for %s", bdevname(dc->bdev, buf));
971 /* Drop ref we took in cached_dev_detach() */
972 closure_put(&dc->disk.cl);
975 void bch_cached_dev_detach(struct cached_dev *dc)
977 lockdep_assert_held(&bch_register_lock);
979 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
982 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
986 * Block the device from being closed and freed until we're finished
989 closure_get(&dc->disk.cl);
991 bch_writeback_queue(dc);
996 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
999 uint32_t rtime = cpu_to_le32(get_seconds());
1000 struct uuid_entry *u;
1001 char buf[BDEVNAME_SIZE];
1003 bdevname(dc->bdev, buf);
1005 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
1006 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
1010 pr_err("Can't attach %s: already attached", buf);
1014 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1015 pr_err("Can't attach %s: shutting down", buf);
1019 if (dc->sb.block_size < c->sb.block_size) {
1021 pr_err("Couldn't attach %s: block size less than set's block size",
1026 u = uuid_find(c, dc->sb.uuid);
1029 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1030 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1031 memcpy(u->uuid, invalid_uuid, 16);
1032 u->invalidated = cpu_to_le32(get_seconds());
1037 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1038 pr_err("Couldn't find uuid for %s in set", buf);
1042 u = uuid_find_empty(c);
1044 pr_err("Not caching %s, no room for UUID", buf);
1049 /* Deadlocks since we're called via sysfs...
1050 sysfs_remove_file(&dc->kobj, &sysfs_attach);
1053 if (bch_is_zero(u->uuid, 16)) {
1055 closure_init_stack(&cl);
1057 memcpy(u->uuid, dc->sb.uuid, 16);
1058 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1059 u->first_reg = u->last_reg = rtime;
1062 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
1063 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1065 bch_write_bdev_super(dc, &cl);
1068 u->last_reg = rtime;
1072 bcache_device_attach(&dc->disk, c, u - c->uuids);
1073 list_move(&dc->list, &c->cached_devs);
1074 calc_cached_dev_sectors(c);
1078 * dc->c must be set before dc->count != 0 - paired with the mb in
1081 refcount_set(&dc->count, 1);
1083 /* Block writeback thread, but spawn it */
1084 down_write(&dc->writeback_lock);
1085 if (bch_cached_dev_writeback_start(dc)) {
1086 up_write(&dc->writeback_lock);
1090 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1091 bch_sectors_dirty_init(&dc->disk);
1092 atomic_set(&dc->has_dirty, 1);
1093 bch_writeback_queue(dc);
1096 bch_cached_dev_run(dc);
1097 bcache_device_link(&dc->disk, c, "bdev");
1099 /* Allow the writeback thread to proceed */
1100 up_write(&dc->writeback_lock);
1102 pr_info("Caching %s as %s on set %pU",
1103 bdevname(dc->bdev, buf), dc->disk.disk->disk_name,
1104 dc->disk.c->sb.set_uuid);
1108 void bch_cached_dev_release(struct kobject *kobj)
1110 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1113 module_put(THIS_MODULE);
1116 static void cached_dev_free(struct closure *cl)
1118 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1120 mutex_lock(&bch_register_lock);
1122 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1123 cancel_writeback_rate_update_dwork(dc);
1125 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1126 kthread_stop(dc->writeback_thread);
1127 if (dc->writeback_write_wq)
1128 destroy_workqueue(dc->writeback_write_wq);
1130 if (atomic_read(&dc->running))
1131 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1132 bcache_device_free(&dc->disk);
1133 list_del(&dc->list);
1135 mutex_unlock(&bch_register_lock);
1137 if (!IS_ERR_OR_NULL(dc->bdev))
1138 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1140 wake_up(&unregister_wait);
1142 kobject_put(&dc->disk.kobj);
1145 static void cached_dev_flush(struct closure *cl)
1147 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1148 struct bcache_device *d = &dc->disk;
1150 mutex_lock(&bch_register_lock);
1151 bcache_device_unlink(d);
1152 mutex_unlock(&bch_register_lock);
1154 bch_cache_accounting_destroy(&dc->accounting);
1155 kobject_del(&d->kobj);
1157 continue_at(cl, cached_dev_free, system_wq);
1160 static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
1164 struct request_queue *q = bdev_get_queue(dc->bdev);
1166 __module_get(THIS_MODULE);
1167 INIT_LIST_HEAD(&dc->list);
1168 closure_init(&dc->disk.cl, NULL);
1169 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1170 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1171 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1172 sema_init(&dc->sb_write_mutex, 1);
1173 INIT_LIST_HEAD(&dc->io_lru);
1174 spin_lock_init(&dc->io_lock);
1175 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1177 dc->sequential_cutoff = 4 << 20;
1179 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1180 list_add(&io->lru, &dc->io_lru);
1181 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1184 dc->disk.stripe_size = q->limits.io_opt >> 9;
1186 if (dc->disk.stripe_size)
1187 dc->partial_stripes_expensive =
1188 q->limits.raid_partial_stripes_expensive;
1190 ret = bcache_device_init(&dc->disk, block_size,
1191 dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
1195 dc->disk.disk->queue->backing_dev_info->ra_pages =
1196 max(dc->disk.disk->queue->backing_dev_info->ra_pages,
1197 q->backing_dev_info->ra_pages);
1199 /* default to auto */
1200 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1202 bch_cached_dev_request_init(dc);
1203 bch_cached_dev_writeback_init(dc);
1207 /* Cached device - bcache superblock */
1209 static void register_bdev(struct cache_sb *sb, struct page *sb_page,
1210 struct block_device *bdev,
1211 struct cached_dev *dc)
1213 char name[BDEVNAME_SIZE];
1214 const char *err = "cannot allocate memory";
1215 struct cache_set *c;
1217 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1219 dc->bdev->bd_holder = dc;
1221 bio_init(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1);
1222 bio_first_bvec_all(&dc->sb_bio)->bv_page = sb_page;
1225 if (cached_dev_init(dc, sb->block_size << 9))
1228 err = "error creating kobject";
1229 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1232 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1235 pr_info("registered backing device %s", bdevname(bdev, name));
1237 list_add(&dc->list, &uncached_devices);
1238 list_for_each_entry(c, &bch_cache_sets, list)
1239 bch_cached_dev_attach(dc, c, NULL);
1241 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1242 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
1243 bch_cached_dev_run(dc);
1247 pr_notice("error opening %s: %s", bdevname(bdev, name), err);
1248 bcache_device_stop(&dc->disk);
1251 /* Flash only volumes */
1253 void bch_flash_dev_release(struct kobject *kobj)
1255 struct bcache_device *d = container_of(kobj, struct bcache_device,
1260 static void flash_dev_free(struct closure *cl)
1262 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1263 mutex_lock(&bch_register_lock);
1264 bcache_device_free(d);
1265 mutex_unlock(&bch_register_lock);
1266 kobject_put(&d->kobj);
1269 static void flash_dev_flush(struct closure *cl)
1271 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1273 mutex_lock(&bch_register_lock);
1274 bcache_device_unlink(d);
1275 mutex_unlock(&bch_register_lock);
1276 kobject_del(&d->kobj);
1277 continue_at(cl, flash_dev_free, system_wq);
1280 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1282 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1287 closure_init(&d->cl, NULL);
1288 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1290 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1292 if (bcache_device_init(d, block_bytes(c), u->sectors))
1295 bcache_device_attach(d, c, u - c->uuids);
1296 bch_sectors_dirty_init(d);
1297 bch_flash_dev_request_init(d);
1300 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1303 bcache_device_link(d, c, "volume");
1307 kobject_put(&d->kobj);
1311 static int flash_devs_run(struct cache_set *c)
1314 struct uuid_entry *u;
1317 u < c->uuids + c->nr_uuids && !ret;
1319 if (UUID_FLASH_ONLY(u))
1320 ret = flash_dev_run(c, u);
1325 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1327 struct uuid_entry *u;
1329 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1332 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1335 u = uuid_find_empty(c);
1337 pr_err("Can't create volume, no room for UUID");
1341 get_random_bytes(u->uuid, 16);
1342 memset(u->label, 0, 32);
1343 u->first_reg = u->last_reg = cpu_to_le32(get_seconds());
1345 SET_UUID_FLASH_ONLY(u, 1);
1346 u->sectors = size >> 9;
1350 return flash_dev_run(c, u);
1356 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1360 if (c->on_error != ON_ERROR_PANIC &&
1361 test_bit(CACHE_SET_STOPPING, &c->flags))
1364 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1365 pr_warn("CACHE_SET_IO_DISABLE already set");
1367 /* XXX: we can be called from atomic context
1368 acquire_console_sem();
1371 printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid);
1373 va_start(args, fmt);
1377 printk(", disabling caching\n");
1379 if (c->on_error == ON_ERROR_PANIC)
1380 panic("panic forced after error\n");
1382 bch_cache_set_unregister(c);
1386 void bch_cache_set_release(struct kobject *kobj)
1388 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1390 module_put(THIS_MODULE);
1393 static void cache_set_free(struct closure *cl)
1395 struct cache_set *c = container_of(cl, struct cache_set, cl);
1399 if (!IS_ERR_OR_NULL(c->debug))
1400 debugfs_remove(c->debug);
1402 bch_open_buckets_free(c);
1403 bch_btree_cache_free(c);
1404 bch_journal_free(c);
1406 for_each_cache(ca, c, i)
1409 c->cache[ca->sb.nr_this_dev] = NULL;
1410 kobject_put(&ca->kobj);
1413 bch_bset_sort_state_free(&c->sort);
1414 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
1416 if (c->moving_gc_wq)
1417 destroy_workqueue(c->moving_gc_wq);
1419 bioset_free(c->bio_split);
1421 mempool_destroy(c->fill_iter);
1423 mempool_destroy(c->bio_meta);
1425 mempool_destroy(c->search);
1428 mutex_lock(&bch_register_lock);
1430 mutex_unlock(&bch_register_lock);
1432 pr_info("Cache set %pU unregistered", c->sb.set_uuid);
1433 wake_up(&unregister_wait);
1435 closure_debug_destroy(&c->cl);
1436 kobject_put(&c->kobj);
1439 static void cache_set_flush(struct closure *cl)
1441 struct cache_set *c = container_of(cl, struct cache_set, caching);
1446 bch_cache_accounting_destroy(&c->accounting);
1448 kobject_put(&c->internal);
1449 kobject_del(&c->kobj);
1452 kthread_stop(c->gc_thread);
1454 if (!IS_ERR_OR_NULL(c->root))
1455 list_add(&c->root->list, &c->btree_cache);
1457 /* Should skip this if we're unregistering because of an error */
1458 list_for_each_entry(b, &c->btree_cache, list) {
1459 mutex_lock(&b->write_lock);
1460 if (btree_node_dirty(b))
1461 __bch_btree_node_write(b, NULL);
1462 mutex_unlock(&b->write_lock);
1465 for_each_cache(ca, c, i)
1466 if (ca->alloc_thread)
1467 kthread_stop(ca->alloc_thread);
1469 if (c->journal.cur) {
1470 cancel_delayed_work_sync(&c->journal.work);
1471 /* flush last journal entry if needed */
1472 c->journal.work.work.func(&c->journal.work.work);
1479 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1480 * cache set is unregistering due to too many I/O errors. In this condition,
1481 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1482 * value and whether the broken cache has dirty data:
1484 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1485 * BCH_CACHED_STOP_AUTO 0 NO
1486 * BCH_CACHED_STOP_AUTO 1 YES
1487 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1488 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1490 * The expected behavior is, if stop_when_cache_set_failed is configured to
1491 * "auto" via sysfs interface, the bcache device will not be stopped if the
1492 * backing device is clean on the broken cache device.
1494 static void conditional_stop_bcache_device(struct cache_set *c,
1495 struct bcache_device *d,
1496 struct cached_dev *dc)
1498 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1499 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.",
1500 d->disk->disk_name, c->sb.set_uuid);
1501 bcache_device_stop(d);
1502 } else if (atomic_read(&dc->has_dirty)) {
1504 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1505 * and dc->has_dirty == 1
1507 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.",
1508 d->disk->disk_name);
1509 bcache_device_stop(d);
1512 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1513 * and dc->has_dirty == 0
1515 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.",
1516 d->disk->disk_name);
1520 static void __cache_set_unregister(struct closure *cl)
1522 struct cache_set *c = container_of(cl, struct cache_set, caching);
1523 struct cached_dev *dc;
1524 struct bcache_device *d;
1527 mutex_lock(&bch_register_lock);
1529 for (i = 0; i < c->devices_max_used; i++) {
1534 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1535 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1536 dc = container_of(d, struct cached_dev, disk);
1537 bch_cached_dev_detach(dc);
1538 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1539 conditional_stop_bcache_device(c, d, dc);
1541 bcache_device_stop(d);
1545 mutex_unlock(&bch_register_lock);
1547 continue_at(cl, cache_set_flush, system_wq);
1550 void bch_cache_set_stop(struct cache_set *c)
1552 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1553 closure_queue(&c->caching);
1556 void bch_cache_set_unregister(struct cache_set *c)
1558 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1559 bch_cache_set_stop(c);
1562 #define alloc_bucket_pages(gfp, c) \
1563 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
1565 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1568 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1572 __module_get(THIS_MODULE);
1573 closure_init(&c->cl, NULL);
1574 set_closure_fn(&c->cl, cache_set_free, system_wq);
1576 closure_init(&c->caching, &c->cl);
1577 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1579 /* Maybe create continue_at_noreturn() and use it here? */
1580 closure_set_stopped(&c->cl);
1581 closure_put(&c->cl);
1583 kobject_init(&c->kobj, &bch_cache_set_ktype);
1584 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1586 bch_cache_accounting_init(&c->accounting, &c->cl);
1588 memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1589 c->sb.block_size = sb->block_size;
1590 c->sb.bucket_size = sb->bucket_size;
1591 c->sb.nr_in_set = sb->nr_in_set;
1592 c->sb.last_mount = sb->last_mount;
1593 c->bucket_bits = ilog2(sb->bucket_size);
1594 c->block_bits = ilog2(sb->block_size);
1595 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
1596 c->devices_max_used = 0;
1597 c->btree_pages = bucket_pages(c);
1598 if (c->btree_pages > BTREE_MAX_PAGES)
1599 c->btree_pages = max_t(int, c->btree_pages / 4,
1602 sema_init(&c->sb_write_mutex, 1);
1603 mutex_init(&c->bucket_lock);
1604 init_waitqueue_head(&c->btree_cache_wait);
1605 init_waitqueue_head(&c->bucket_wait);
1606 init_waitqueue_head(&c->gc_wait);
1607 sema_init(&c->uuid_write_mutex, 1);
1609 spin_lock_init(&c->btree_gc_time.lock);
1610 spin_lock_init(&c->btree_split_time.lock);
1611 spin_lock_init(&c->btree_read_time.lock);
1613 bch_moving_init_cache_set(c);
1615 INIT_LIST_HEAD(&c->list);
1616 INIT_LIST_HEAD(&c->cached_devs);
1617 INIT_LIST_HEAD(&c->btree_cache);
1618 INIT_LIST_HEAD(&c->btree_cache_freeable);
1619 INIT_LIST_HEAD(&c->btree_cache_freed);
1620 INIT_LIST_HEAD(&c->data_buckets);
1622 c->search = mempool_create_slab_pool(32, bch_search_cache);
1626 iter_size = (sb->bucket_size / sb->block_size + 1) *
1627 sizeof(struct btree_iter_set);
1629 if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) ||
1630 !(c->bio_meta = mempool_create_kmalloc_pool(2,
1631 sizeof(struct bbio) + sizeof(struct bio_vec) *
1632 bucket_pages(c))) ||
1633 !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) ||
1634 !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio),
1636 BIOSET_NEED_RESCUER)) ||
1637 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
1638 !(c->moving_gc_wq = alloc_workqueue("bcache_gc",
1639 WQ_MEM_RECLAIM, 0)) ||
1640 bch_journal_alloc(c) ||
1641 bch_btree_cache_alloc(c) ||
1642 bch_open_buckets_alloc(c) ||
1643 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1646 c->congested_read_threshold_us = 2000;
1647 c->congested_write_threshold_us = 20000;
1648 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1649 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1653 bch_cache_set_unregister(c);
1657 static void run_cache_set(struct cache_set *c)
1659 const char *err = "cannot allocate memory";
1660 struct cached_dev *dc, *t;
1665 closure_init_stack(&cl);
1667 for_each_cache(ca, c, i)
1668 c->nbuckets += ca->sb.nbuckets;
1671 if (CACHE_SYNC(&c->sb)) {
1676 err = "cannot allocate memory for journal";
1677 if (bch_journal_read(c, &journal))
1680 pr_debug("btree_journal_read() done");
1682 err = "no journal entries found";
1683 if (list_empty(&journal))
1686 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1688 err = "IO error reading priorities";
1689 for_each_cache(ca, c, i)
1690 prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]);
1693 * If prio_read() fails it'll call cache_set_error and we'll
1694 * tear everything down right away, but if we perhaps checked
1695 * sooner we could avoid journal replay.
1700 err = "bad btree root";
1701 if (__bch_btree_ptr_invalid(c, k))
1704 err = "error reading btree root";
1705 c->root = bch_btree_node_get(c, NULL, k, j->btree_level, true, NULL);
1706 if (IS_ERR_OR_NULL(c->root))
1709 list_del_init(&c->root->list);
1710 rw_unlock(true, c->root);
1712 err = uuid_read(c, j, &cl);
1716 err = "error in recovery";
1717 if (bch_btree_check(c))
1720 bch_journal_mark(c, &journal);
1721 bch_initial_gc_finish(c);
1722 pr_debug("btree_check() done");
1725 * bcache_journal_next() can't happen sooner, or
1726 * btree_gc_finish() will give spurious errors about last_gc >
1727 * gc_gen - this is a hack but oh well.
1729 bch_journal_next(&c->journal);
1731 err = "error starting allocator thread";
1732 for_each_cache(ca, c, i)
1733 if (bch_cache_allocator_start(ca))
1737 * First place it's safe to allocate: btree_check() and
1738 * btree_gc_finish() have to run before we have buckets to
1739 * allocate, and bch_bucket_alloc_set() might cause a journal
1740 * entry to be written so bcache_journal_next() has to be called
1743 * If the uuids were in the old format we have to rewrite them
1744 * before the next journal entry is written:
1746 if (j->version < BCACHE_JSET_VERSION_UUID)
1749 bch_journal_replay(c, &journal);
1751 pr_notice("invalidating existing data");
1753 for_each_cache(ca, c, i) {
1756 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
1757 2, SB_JOURNAL_BUCKETS);
1759 for (j = 0; j < ca->sb.keys; j++)
1760 ca->sb.d[j] = ca->sb.first_bucket + j;
1763 bch_initial_gc_finish(c);
1765 err = "error starting allocator thread";
1766 for_each_cache(ca, c, i)
1767 if (bch_cache_allocator_start(ca))
1770 mutex_lock(&c->bucket_lock);
1771 for_each_cache(ca, c, i)
1773 mutex_unlock(&c->bucket_lock);
1775 err = "cannot allocate new UUID bucket";
1776 if (__uuid_write(c))
1779 err = "cannot allocate new btree root";
1780 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
1781 if (IS_ERR_OR_NULL(c->root))
1784 mutex_lock(&c->root->write_lock);
1785 bkey_copy_key(&c->root->key, &MAX_KEY);
1786 bch_btree_node_write(c->root, &cl);
1787 mutex_unlock(&c->root->write_lock);
1789 bch_btree_set_root(c->root);
1790 rw_unlock(true, c->root);
1793 * We don't want to write the first journal entry until
1794 * everything is set up - fortunately journal entries won't be
1795 * written until the SET_CACHE_SYNC() here:
1797 SET_CACHE_SYNC(&c->sb, true);
1799 bch_journal_next(&c->journal);
1800 bch_journal_meta(c, &cl);
1803 err = "error starting gc thread";
1804 if (bch_gc_thread_start(c))
1808 c->sb.last_mount = get_seconds();
1809 bcache_write_super(c);
1811 list_for_each_entry_safe(dc, t, &uncached_devices, list)
1812 bch_cached_dev_attach(dc, c, NULL);
1816 set_bit(CACHE_SET_RUNNING, &c->flags);
1820 /* XXX: test this, it's broken */
1821 bch_cache_set_error(c, "%s", err);
1824 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
1826 return ca->sb.block_size == c->sb.block_size &&
1827 ca->sb.bucket_size == c->sb.bucket_size &&
1828 ca->sb.nr_in_set == c->sb.nr_in_set;
1831 static const char *register_cache_set(struct cache *ca)
1834 const char *err = "cannot allocate memory";
1835 struct cache_set *c;
1837 list_for_each_entry(c, &bch_cache_sets, list)
1838 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
1839 if (c->cache[ca->sb.nr_this_dev])
1840 return "duplicate cache set member";
1842 if (!can_attach_cache(ca, c))
1843 return "cache sb does not match set";
1845 if (!CACHE_SYNC(&ca->sb))
1846 SET_CACHE_SYNC(&c->sb, false);
1851 c = bch_cache_set_alloc(&ca->sb);
1855 err = "error creating kobject";
1856 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
1857 kobject_add(&c->internal, &c->kobj, "internal"))
1860 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
1863 bch_debug_init_cache_set(c);
1865 list_add(&c->list, &bch_cache_sets);
1867 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
1868 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
1869 sysfs_create_link(&c->kobj, &ca->kobj, buf))
1872 if (ca->sb.seq > c->sb.seq) {
1873 c->sb.version = ca->sb.version;
1874 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
1875 c->sb.flags = ca->sb.flags;
1876 c->sb.seq = ca->sb.seq;
1877 pr_debug("set version = %llu", c->sb.version);
1880 kobject_get(&ca->kobj);
1882 ca->set->cache[ca->sb.nr_this_dev] = ca;
1883 c->cache_by_alloc[c->caches_loaded++] = ca;
1885 if (c->caches_loaded == c->sb.nr_in_set)
1890 bch_cache_set_unregister(c);
1896 void bch_cache_release(struct kobject *kobj)
1898 struct cache *ca = container_of(kobj, struct cache, kobj);
1902 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca);
1903 ca->set->cache[ca->sb.nr_this_dev] = NULL;
1906 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
1907 kfree(ca->prio_buckets);
1910 free_heap(&ca->heap);
1911 free_fifo(&ca->free_inc);
1913 for (i = 0; i < RESERVE_NR; i++)
1914 free_fifo(&ca->free[i]);
1916 if (ca->sb_bio.bi_inline_vecs[0].bv_page)
1917 put_page(bio_first_page_all(&ca->sb_bio));
1919 if (!IS_ERR_OR_NULL(ca->bdev))
1920 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1923 module_put(THIS_MODULE);
1926 static int cache_alloc(struct cache *ca)
1929 size_t btree_buckets;
1932 __module_get(THIS_MODULE);
1933 kobject_init(&ca->kobj, &bch_cache_ktype);
1935 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
1938 * when ca->sb.njournal_buckets is not zero, journal exists,
1939 * and in bch_journal_replay(), tree node may split,
1940 * so bucket of RESERVE_BTREE type is needed,
1941 * the worst situation is all journal buckets are valid journal,
1942 * and all the keys need to replay,
1943 * so the number of RESERVE_BTREE type buckets should be as much
1944 * as journal buckets
1946 btree_buckets = ca->sb.njournal_buckets ?: 8;
1947 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
1949 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets, GFP_KERNEL) ||
1950 !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) ||
1951 !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) ||
1952 !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) ||
1953 !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) ||
1954 !init_heap(&ca->heap, free << 3, GFP_KERNEL) ||
1955 !(ca->buckets = vzalloc(sizeof(struct bucket) *
1956 ca->sb.nbuckets)) ||
1957 !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) *
1959 !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)))
1962 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
1964 for_each_bucket(b, ca)
1965 atomic_set(&b->pin, 0);
1970 static int register_cache(struct cache_sb *sb, struct page *sb_page,
1971 struct block_device *bdev, struct cache *ca)
1973 char name[BDEVNAME_SIZE];
1974 const char *err = NULL; /* must be set for any error case */
1977 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
1979 ca->bdev->bd_holder = ca;
1981 bio_init(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1);
1982 bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page;
1985 if (blk_queue_discard(bdev_get_queue(ca->bdev)))
1986 ca->discard = CACHE_DISCARD(&ca->sb);
1988 ret = cache_alloc(ca);
1991 err = "cache_alloc(): -ENOMEM";
1993 err = "cache_alloc(): unknown error";
1997 if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache")) {
1998 err = "error calling kobject_add";
2003 mutex_lock(&bch_register_lock);
2004 err = register_cache_set(ca);
2005 mutex_unlock(&bch_register_lock);
2012 pr_info("registered cache device %s", bdevname(bdev, name));
2015 kobject_put(&ca->kobj);
2019 pr_notice("error opening %s: %s", bdevname(bdev, name), err);
2024 /* Global interfaces/init */
2026 static ssize_t register_bcache(struct kobject *, struct kobj_attribute *,
2027 const char *, size_t);
2029 kobj_attribute_write(register, register_bcache);
2030 kobj_attribute_write(register_quiet, register_bcache);
2032 static bool bch_is_open_backing(struct block_device *bdev) {
2033 struct cache_set *c, *tc;
2034 struct cached_dev *dc, *t;
2036 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2037 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2038 if (dc->bdev == bdev)
2040 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2041 if (dc->bdev == bdev)
2046 static bool bch_is_open_cache(struct block_device *bdev) {
2047 struct cache_set *c, *tc;
2051 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2052 for_each_cache(ca, c, i)
2053 if (ca->bdev == bdev)
2058 static bool bch_is_open(struct block_device *bdev) {
2059 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
2062 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2063 const char *buffer, size_t size)
2066 const char *err = "cannot allocate memory";
2068 struct cache_sb *sb = NULL;
2069 struct block_device *bdev = NULL;
2070 struct page *sb_page = NULL;
2072 if (!try_module_get(THIS_MODULE))
2075 if (!(path = kstrndup(buffer, size, GFP_KERNEL)) ||
2076 !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL)))
2079 err = "failed to open device";
2080 bdev = blkdev_get_by_path(strim(path),
2081 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2084 if (bdev == ERR_PTR(-EBUSY)) {
2085 bdev = lookup_bdev(strim(path));
2086 mutex_lock(&bch_register_lock);
2087 if (!IS_ERR(bdev) && bch_is_open(bdev))
2088 err = "device already registered";
2090 err = "device busy";
2091 mutex_unlock(&bch_register_lock);
2094 if (attr == &ksysfs_register_quiet)
2100 err = "failed to set blocksize";
2101 if (set_blocksize(bdev, 4096))
2104 err = read_super(sb, bdev, &sb_page);
2108 if (SB_IS_BDEV(sb)) {
2109 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2113 mutex_lock(&bch_register_lock);
2114 register_bdev(sb, sb_page, bdev, dc);
2115 mutex_unlock(&bch_register_lock);
2117 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2121 if (register_cache(sb, sb_page, bdev, ca) != 0)
2129 module_put(THIS_MODULE);
2133 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2135 pr_info("error opening %s: %s", path, err);
2140 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2142 if (code == SYS_DOWN ||
2144 code == SYS_POWER_OFF) {
2146 unsigned long start = jiffies;
2147 bool stopped = false;
2149 struct cache_set *c, *tc;
2150 struct cached_dev *dc, *tdc;
2152 mutex_lock(&bch_register_lock);
2154 if (list_empty(&bch_cache_sets) &&
2155 list_empty(&uncached_devices))
2158 pr_info("Stopping all devices:");
2160 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2161 bch_cache_set_stop(c);
2163 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2164 bcache_device_stop(&dc->disk);
2166 /* What's a condition variable? */
2168 long timeout = start + 2 * HZ - jiffies;
2170 stopped = list_empty(&bch_cache_sets) &&
2171 list_empty(&uncached_devices);
2173 if (timeout < 0 || stopped)
2176 prepare_to_wait(&unregister_wait, &wait,
2177 TASK_UNINTERRUPTIBLE);
2179 mutex_unlock(&bch_register_lock);
2180 schedule_timeout(timeout);
2181 mutex_lock(&bch_register_lock);
2184 finish_wait(&unregister_wait, &wait);
2187 pr_info("All devices stopped");
2189 pr_notice("Timeout waiting for devices to be closed");
2191 mutex_unlock(&bch_register_lock);
2197 static struct notifier_block reboot = {
2198 .notifier_call = bcache_reboot,
2199 .priority = INT_MAX, /* before any real devices */
2202 static void bcache_exit(void)
2207 kobject_put(bcache_kobj);
2209 destroy_workqueue(bcache_wq);
2211 unregister_blkdev(bcache_major, "bcache");
2212 unregister_reboot_notifier(&reboot);
2213 mutex_destroy(&bch_register_lock);
2216 static int __init bcache_init(void)
2218 static const struct attribute *files[] = {
2219 &ksysfs_register.attr,
2220 &ksysfs_register_quiet.attr,
2224 mutex_init(&bch_register_lock);
2225 init_waitqueue_head(&unregister_wait);
2226 register_reboot_notifier(&reboot);
2228 bcache_major = register_blkdev(0, "bcache");
2229 if (bcache_major < 0) {
2230 unregister_reboot_notifier(&reboot);
2231 mutex_destroy(&bch_register_lock);
2232 return bcache_major;
2235 if (!(bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0)) ||
2236 !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) ||
2237 bch_request_init() ||
2238 bch_debug_init(bcache_kobj) || closure_debug_init() ||
2239 sysfs_create_files(bcache_kobj, files))
2248 module_exit(bcache_exit);
2249 module_init(bcache_init);