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"
18 #include <linux/blkdev.h>
19 #include <linux/pagemap.h>
20 #include <linux/debugfs.h>
21 #include <linux/genhd.h>
22 #include <linux/idr.h>
23 #include <linux/kthread.h>
24 #include <linux/workqueue.h>
25 #include <linux/module.h>
26 #include <linux/random.h>
27 #include <linux/reboot.h>
28 #include <linux/sysfs.h>
30 unsigned int bch_cutoff_writeback;
31 unsigned int bch_cutoff_writeback_sync;
33 static const char bcache_magic[] = {
34 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
35 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
38 static const char invalid_uuid[] = {
39 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
40 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
43 static struct kobject *bcache_kobj;
44 struct mutex bch_register_lock;
45 bool bcache_is_reboot;
46 LIST_HEAD(bch_cache_sets);
47 static LIST_HEAD(uncached_devices);
49 static int bcache_major;
50 static DEFINE_IDA(bcache_device_idx);
51 static wait_queue_head_t unregister_wait;
52 struct workqueue_struct *bcache_wq;
53 struct workqueue_struct *bch_flush_wq;
54 struct workqueue_struct *bch_journal_wq;
57 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
58 /* limitation of partitions number on single bcache device */
59 #define BCACHE_MINORS 128
60 /* limitation of bcache devices number on single system */
61 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
65 static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s)
67 unsigned int bucket_size = le16_to_cpu(s->bucket_size);
69 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
70 if (bch_has_feature_large_bucket(sb)) {
71 unsigned int max, order;
73 max = sizeof(unsigned int) * BITS_PER_BYTE - 1;
74 order = le16_to_cpu(s->bucket_size);
76 * bcache tool will make sure the overflow won't
77 * happen, an error message here is enough.
80 pr_err("Bucket size (1 << %u) overflows\n",
82 bucket_size = 1 << order;
83 } else if (bch_has_feature_obso_large_bucket(sb)) {
85 le16_to_cpu(s->obso_bucket_size_hi) << 16;
92 static const char *read_super_common(struct cache_sb *sb, struct block_device *bdev,
93 struct cache_sb_disk *s)
98 sb->first_bucket= le16_to_cpu(s->first_bucket);
99 sb->nbuckets = le64_to_cpu(s->nbuckets);
100 sb->bucket_size = get_bucket_size(sb, s);
102 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
103 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
105 err = "Too many journal buckets";
106 if (sb->keys > SB_JOURNAL_BUCKETS)
109 err = "Too many buckets";
110 if (sb->nbuckets > LONG_MAX)
113 err = "Not enough buckets";
114 if (sb->nbuckets < 1 << 7)
117 err = "Bad block size (not power of 2)";
118 if (!is_power_of_2(sb->block_size))
121 err = "Bad block size (larger than page size)";
122 if (sb->block_size > PAGE_SECTORS)
125 err = "Bad bucket size (not power of 2)";
126 if (!is_power_of_2(sb->bucket_size))
129 err = "Bad bucket size (smaller than page size)";
130 if (sb->bucket_size < PAGE_SECTORS)
133 err = "Invalid superblock: device too small";
134 if (get_capacity(bdev->bd_disk) <
135 sb->bucket_size * sb->nbuckets)
139 if (bch_is_zero(sb->set_uuid, 16))
142 err = "Bad cache device number in set";
143 if (!sb->nr_in_set ||
144 sb->nr_in_set <= sb->nr_this_dev ||
145 sb->nr_in_set > MAX_CACHES_PER_SET)
148 err = "Journal buckets not sequential";
149 for (i = 0; i < sb->keys; i++)
150 if (sb->d[i] != sb->first_bucket + i)
153 err = "Too many journal buckets";
154 if (sb->first_bucket + sb->keys > sb->nbuckets)
157 err = "Invalid superblock: first bucket comes before end of super";
158 if (sb->first_bucket * sb->bucket_size < 16)
167 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
168 struct cache_sb_disk **res)
171 struct cache_sb_disk *s;
175 page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
176 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
179 s = page_address(page) + offset_in_page(SB_OFFSET);
181 sb->offset = le64_to_cpu(s->offset);
182 sb->version = le64_to_cpu(s->version);
184 memcpy(sb->magic, s->magic, 16);
185 memcpy(sb->uuid, s->uuid, 16);
186 memcpy(sb->set_uuid, s->set_uuid, 16);
187 memcpy(sb->label, s->label, SB_LABEL_SIZE);
189 sb->flags = le64_to_cpu(s->flags);
190 sb->seq = le64_to_cpu(s->seq);
191 sb->last_mount = le32_to_cpu(s->last_mount);
192 sb->keys = le16_to_cpu(s->keys);
194 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
195 sb->d[i] = le64_to_cpu(s->d[i]);
197 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u\n",
198 sb->version, sb->flags, sb->seq, sb->keys);
200 err = "Not a bcache superblock (bad offset)";
201 if (sb->offset != SB_SECTOR)
204 err = "Not a bcache superblock (bad magic)";
205 if (memcmp(sb->magic, bcache_magic, 16))
208 err = "Bad checksum";
209 if (s->csum != csum_set(s))
213 if (bch_is_zero(sb->uuid, 16))
216 sb->block_size = le16_to_cpu(s->block_size);
218 err = "Superblock block size smaller than device block size";
219 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
222 switch (sb->version) {
223 case BCACHE_SB_VERSION_BDEV:
224 sb->data_offset = BDEV_DATA_START_DEFAULT;
226 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
227 case BCACHE_SB_VERSION_BDEV_WITH_FEATURES:
228 sb->data_offset = le64_to_cpu(s->data_offset);
230 err = "Bad data offset";
231 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
235 case BCACHE_SB_VERSION_CDEV:
236 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
237 err = read_super_common(sb, bdev, s);
241 case BCACHE_SB_VERSION_CDEV_WITH_FEATURES:
243 * Feature bits are needed in read_super_common(),
244 * convert them firstly.
246 sb->feature_compat = le64_to_cpu(s->feature_compat);
247 sb->feature_incompat = le64_to_cpu(s->feature_incompat);
248 sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat);
250 /* Check incompatible features */
251 err = "Unsupported compatible feature found";
252 if (bch_has_unknown_compat_features(sb))
255 err = "Unsupported read-only compatible feature found";
256 if (bch_has_unknown_ro_compat_features(sb))
259 err = "Unsupported incompatible feature found";
260 if (bch_has_unknown_incompat_features(sb))
263 err = read_super_common(sb, bdev, s);
268 err = "Unsupported superblock version";
272 sb->last_mount = (u32)ktime_get_real_seconds();
280 static void write_bdev_super_endio(struct bio *bio)
282 struct cached_dev *dc = bio->bi_private;
285 bch_count_backing_io_errors(dc, bio);
287 closure_put(&dc->sb_write);
290 static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
295 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
296 bio->bi_iter.bi_sector = SB_SECTOR;
297 __bio_add_page(bio, virt_to_page(out), SB_SIZE,
298 offset_in_page(out));
300 out->offset = cpu_to_le64(sb->offset);
302 memcpy(out->uuid, sb->uuid, 16);
303 memcpy(out->set_uuid, sb->set_uuid, 16);
304 memcpy(out->label, sb->label, SB_LABEL_SIZE);
306 out->flags = cpu_to_le64(sb->flags);
307 out->seq = cpu_to_le64(sb->seq);
309 out->last_mount = cpu_to_le32(sb->last_mount);
310 out->first_bucket = cpu_to_le16(sb->first_bucket);
311 out->keys = cpu_to_le16(sb->keys);
313 for (i = 0; i < sb->keys; i++)
314 out->d[i] = cpu_to_le64(sb->d[i]);
316 if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
317 out->feature_compat = cpu_to_le64(sb->feature_compat);
318 out->feature_incompat = cpu_to_le64(sb->feature_incompat);
319 out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
322 out->version = cpu_to_le64(sb->version);
323 out->csum = csum_set(out);
325 pr_debug("ver %llu, flags %llu, seq %llu\n",
326 sb->version, sb->flags, sb->seq);
331 static void bch_write_bdev_super_unlock(struct closure *cl)
333 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
335 up(&dc->sb_write_mutex);
338 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
340 struct closure *cl = &dc->sb_write;
341 struct bio *bio = &dc->sb_bio;
343 down(&dc->sb_write_mutex);
344 closure_init(cl, parent);
346 bio_init(bio, dc->sb_bv, 1);
347 bio_set_dev(bio, dc->bdev);
348 bio->bi_end_io = write_bdev_super_endio;
349 bio->bi_private = dc;
352 /* I/O request sent to backing device */
353 __write_super(&dc->sb, dc->sb_disk, bio);
355 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
358 static void write_super_endio(struct bio *bio)
360 struct cache *ca = bio->bi_private;
363 bch_count_io_errors(ca, bio->bi_status, 0,
364 "writing superblock");
365 closure_put(&ca->set->sb_write);
368 static void bcache_write_super_unlock(struct closure *cl)
370 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
372 up(&c->sb_write_mutex);
375 void bcache_write_super(struct cache_set *c)
377 struct closure *cl = &c->sb_write;
378 struct cache *ca = c->cache;
379 struct bio *bio = &ca->sb_bio;
380 unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
382 down(&c->sb_write_mutex);
383 closure_init(cl, &c->cl);
387 if (ca->sb.version < version)
388 ca->sb.version = version;
390 bio_init(bio, ca->sb_bv, 1);
391 bio_set_dev(bio, ca->bdev);
392 bio->bi_end_io = write_super_endio;
393 bio->bi_private = ca;
396 __write_super(&ca->sb, ca->sb_disk, bio);
398 closure_return_with_destructor(cl, bcache_write_super_unlock);
403 static void uuid_endio(struct bio *bio)
405 struct closure *cl = bio->bi_private;
406 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
408 cache_set_err_on(bio->bi_status, c, "accessing uuids");
409 bch_bbio_free(bio, c);
413 static void uuid_io_unlock(struct closure *cl)
415 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
417 up(&c->uuid_write_mutex);
420 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
421 struct bkey *k, struct closure *parent)
423 struct closure *cl = &c->uuid_write;
424 struct uuid_entry *u;
429 down(&c->uuid_write_mutex);
430 closure_init(cl, parent);
432 for (i = 0; i < KEY_PTRS(k); i++) {
433 struct bio *bio = bch_bbio_alloc(c);
435 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
436 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
438 bio->bi_end_io = uuid_endio;
439 bio->bi_private = cl;
440 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
441 bch_bio_map(bio, c->uuids);
443 bch_submit_bbio(bio, c, k, i);
445 if (op != REQ_OP_WRITE)
449 bch_extent_to_text(buf, sizeof(buf), k);
450 pr_debug("%s UUIDs at %s\n", op == REQ_OP_WRITE ? "wrote" : "read", buf);
452 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
453 if (!bch_is_zero(u->uuid, 16))
454 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
455 u - c->uuids, u->uuid, u->label,
456 u->first_reg, u->last_reg, u->invalidated);
458 closure_return_with_destructor(cl, uuid_io_unlock);
461 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
463 struct bkey *k = &j->uuid_bucket;
465 if (__bch_btree_ptr_invalid(c, k))
466 return "bad uuid pointer";
468 bkey_copy(&c->uuid_bucket, k);
469 uuid_io(c, REQ_OP_READ, 0, k, cl);
471 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
472 struct uuid_entry_v0 *u0 = (void *) c->uuids;
473 struct uuid_entry *u1 = (void *) c->uuids;
479 * Since the new uuid entry is bigger than the old, we have to
480 * convert starting at the highest memory address and work down
481 * in order to do it in place
484 for (i = c->nr_uuids - 1;
487 memcpy(u1[i].uuid, u0[i].uuid, 16);
488 memcpy(u1[i].label, u0[i].label, 32);
490 u1[i].first_reg = u0[i].first_reg;
491 u1[i].last_reg = u0[i].last_reg;
492 u1[i].invalidated = u0[i].invalidated;
502 static int __uuid_write(struct cache_set *c)
506 struct cache *ca = c->cache;
509 closure_init_stack(&cl);
510 lockdep_assert_held(&bch_register_lock);
512 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
515 size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS;
516 SET_KEY_SIZE(&k.key, size);
517 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
520 /* Only one bucket used for uuid write */
521 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
523 bkey_copy(&c->uuid_bucket, &k.key);
528 int bch_uuid_write(struct cache_set *c)
530 int ret = __uuid_write(c);
533 bch_journal_meta(c, NULL);
538 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
540 struct uuid_entry *u;
543 u < c->uuids + c->nr_uuids; u++)
544 if (!memcmp(u->uuid, uuid, 16))
550 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
552 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
554 return uuid_find(c, zero_uuid);
558 * Bucket priorities/gens:
560 * For each bucket, we store on disk its
564 * See alloc.c for an explanation of the gen. The priority is used to implement
565 * lru (and in the future other) cache replacement policies; for most purposes
566 * it's just an opaque integer.
568 * The gens and the priorities don't have a whole lot to do with each other, and
569 * it's actually the gens that must be written out at specific times - it's no
570 * big deal if the priorities don't get written, if we lose them we just reuse
571 * buckets in suboptimal order.
573 * On disk they're stored in a packed array, and in as many buckets are required
574 * to fit them all. The buckets we use to store them form a list; the journal
575 * header points to the first bucket, the first bucket points to the second
578 * This code is used by the allocation code; periodically (whenever it runs out
579 * of buckets to allocate from) the allocation code will invalidate some
580 * buckets, but it can't use those buckets until their new gens are safely on
584 static void prio_endio(struct bio *bio)
586 struct cache *ca = bio->bi_private;
588 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
589 bch_bbio_free(bio, ca->set);
590 closure_put(&ca->prio);
593 static void prio_io(struct cache *ca, uint64_t bucket, int op,
594 unsigned long op_flags)
596 struct closure *cl = &ca->prio;
597 struct bio *bio = bch_bbio_alloc(ca->set);
599 closure_init_stack(cl);
601 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
602 bio_set_dev(bio, ca->bdev);
603 bio->bi_iter.bi_size = meta_bucket_bytes(&ca->sb);
605 bio->bi_end_io = prio_endio;
606 bio->bi_private = ca;
607 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
608 bch_bio_map(bio, ca->disk_buckets);
610 closure_bio_submit(ca->set, bio, &ca->prio);
614 int bch_prio_write(struct cache *ca, bool wait)
620 pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n",
621 fifo_used(&ca->free[RESERVE_PRIO]),
622 fifo_used(&ca->free[RESERVE_NONE]),
623 fifo_used(&ca->free_inc));
626 * Pre-check if there are enough free buckets. In the non-blocking
627 * scenario it's better to fail early rather than starting to allocate
628 * buckets and do a cleanup later in case of failure.
631 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
632 fifo_used(&ca->free[RESERVE_NONE]);
633 if (prio_buckets(ca) > avail)
637 closure_init_stack(&cl);
639 lockdep_assert_held(&ca->set->bucket_lock);
641 ca->disk_buckets->seq++;
643 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
644 &ca->meta_sectors_written);
646 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
648 struct prio_set *p = ca->disk_buckets;
649 struct bucket_disk *d = p->data;
650 struct bucket_disk *end = d + prios_per_bucket(ca);
652 for (b = ca->buckets + i * prios_per_bucket(ca);
653 b < ca->buckets + ca->sb.nbuckets && d < end;
655 d->prio = cpu_to_le16(b->prio);
659 p->next_bucket = ca->prio_buckets[i + 1];
660 p->magic = pset_magic(&ca->sb);
661 p->csum = bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8);
663 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
664 BUG_ON(bucket == -1);
666 mutex_unlock(&ca->set->bucket_lock);
667 prio_io(ca, bucket, REQ_OP_WRITE, 0);
668 mutex_lock(&ca->set->bucket_lock);
670 ca->prio_buckets[i] = bucket;
671 atomic_dec_bug(&ca->buckets[bucket].pin);
674 mutex_unlock(&ca->set->bucket_lock);
676 bch_journal_meta(ca->set, &cl);
679 mutex_lock(&ca->set->bucket_lock);
682 * Don't want the old priorities to get garbage collected until after we
683 * finish writing the new ones, and they're journalled
685 for (i = 0; i < prio_buckets(ca); i++) {
686 if (ca->prio_last_buckets[i])
687 __bch_bucket_free(ca,
688 &ca->buckets[ca->prio_last_buckets[i]]);
690 ca->prio_last_buckets[i] = ca->prio_buckets[i];
695 static int prio_read(struct cache *ca, uint64_t bucket)
697 struct prio_set *p = ca->disk_buckets;
698 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
700 unsigned int bucket_nr = 0;
703 for (b = ca->buckets;
704 b < ca->buckets + ca->sb.nbuckets;
707 ca->prio_buckets[bucket_nr] = bucket;
708 ca->prio_last_buckets[bucket_nr] = bucket;
711 prio_io(ca, bucket, REQ_OP_READ, 0);
714 bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) {
715 pr_warn("bad csum reading priorities\n");
719 if (p->magic != pset_magic(&ca->sb)) {
720 pr_warn("bad magic reading priorities\n");
724 bucket = p->next_bucket;
728 b->prio = le16_to_cpu(d->prio);
729 b->gen = b->last_gc = d->gen;
739 static int open_dev(struct block_device *b, fmode_t mode)
741 struct bcache_device *d = b->bd_disk->private_data;
743 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
750 static void release_dev(struct gendisk *b, fmode_t mode)
752 struct bcache_device *d = b->private_data;
757 static int ioctl_dev(struct block_device *b, fmode_t mode,
758 unsigned int cmd, unsigned long arg)
760 struct bcache_device *d = b->bd_disk->private_data;
762 return d->ioctl(d, mode, cmd, arg);
765 static const struct block_device_operations bcache_cached_ops = {
766 .submit_bio = cached_dev_submit_bio,
768 .release = release_dev,
770 .owner = THIS_MODULE,
773 static const struct block_device_operations bcache_flash_ops = {
774 .submit_bio = flash_dev_submit_bio,
776 .release = release_dev,
778 .owner = THIS_MODULE,
781 void bcache_device_stop(struct bcache_device *d)
783 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
786 * - cached device: cached_dev_flush()
787 * - flash dev: flash_dev_flush()
789 closure_queue(&d->cl);
792 static void bcache_device_unlink(struct bcache_device *d)
794 lockdep_assert_held(&bch_register_lock);
796 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
797 struct cache *ca = d->c->cache;
799 sysfs_remove_link(&d->c->kobj, d->name);
800 sysfs_remove_link(&d->kobj, "cache");
802 bd_unlink_disk_holder(ca->bdev, d->disk);
806 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
809 struct cache *ca = c->cache;
812 bd_link_disk_holder(ca->bdev, d->disk);
814 snprintf(d->name, BCACHEDEVNAME_SIZE,
815 "%s%u", name, d->id);
817 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
819 pr_err("Couldn't create device -> cache set symlink\n");
821 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
823 pr_err("Couldn't create cache set -> device symlink\n");
825 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
828 static void bcache_device_detach(struct bcache_device *d)
830 lockdep_assert_held(&bch_register_lock);
832 atomic_dec(&d->c->attached_dev_nr);
834 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
835 struct uuid_entry *u = d->c->uuids + d->id;
837 SET_UUID_FLASH_ONLY(u, 0);
838 memcpy(u->uuid, invalid_uuid, 16);
839 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
840 bch_uuid_write(d->c);
843 bcache_device_unlink(d);
845 d->c->devices[d->id] = NULL;
846 closure_put(&d->c->caching);
850 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
857 if (id >= c->devices_max_used)
858 c->devices_max_used = id + 1;
860 closure_get(&c->caching);
863 static inline int first_minor_to_idx(int first_minor)
865 return (first_minor/BCACHE_MINORS);
868 static inline int idx_to_first_minor(int idx)
870 return (idx * BCACHE_MINORS);
873 static void bcache_device_free(struct bcache_device *d)
875 struct gendisk *disk = d->disk;
877 lockdep_assert_held(&bch_register_lock);
880 pr_info("%s stopped\n", disk->disk_name);
882 pr_err("bcache device (NULL gendisk) stopped\n");
885 bcache_device_detach(d);
888 bool disk_added = (disk->flags & GENHD_FL_UP) != 0;
894 blk_cleanup_queue(disk->queue);
896 ida_simple_remove(&bcache_device_idx,
897 first_minor_to_idx(disk->first_minor));
902 bioset_exit(&d->bio_split);
903 kvfree(d->full_dirty_stripes);
904 kvfree(d->stripe_sectors_dirty);
906 closure_debug_destroy(&d->cl);
909 static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
910 sector_t sectors, struct block_device *cached_bdev,
911 const struct block_device_operations *ops)
913 struct request_queue *q;
914 const size_t max_stripes = min_t(size_t, INT_MAX,
915 SIZE_MAX / sizeof(atomic_t));
920 d->stripe_size = 1 << 31;
922 n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
923 if (!n || n > max_stripes) {
924 pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
930 n = d->nr_stripes * sizeof(atomic_t);
931 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
932 if (!d->stripe_sectors_dirty)
935 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
936 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
937 if (!d->full_dirty_stripes)
940 idx = ida_simple_get(&bcache_device_idx, 0,
941 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
945 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
946 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
949 d->disk = alloc_disk(BCACHE_MINORS);
953 set_capacity(d->disk, sectors);
954 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
956 d->disk->major = bcache_major;
957 d->disk->first_minor = idx_to_first_minor(idx);
959 d->disk->private_data = d;
961 q = blk_alloc_queue(NUMA_NO_NODE);
966 q->limits.max_hw_sectors = UINT_MAX;
967 q->limits.max_sectors = UINT_MAX;
968 q->limits.max_segment_size = UINT_MAX;
969 q->limits.max_segments = BIO_MAX_VECS;
970 blk_queue_max_discard_sectors(q, UINT_MAX);
971 q->limits.discard_granularity = 512;
972 q->limits.io_min = block_size;
973 q->limits.logical_block_size = block_size;
974 q->limits.physical_block_size = block_size;
976 if (q->limits.logical_block_size > PAGE_SIZE && cached_bdev) {
978 * This should only happen with BCACHE_SB_VERSION_BDEV.
979 * Block/page size is checked for BCACHE_SB_VERSION_CDEV.
981 pr_info("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
982 d->disk->disk_name, q->limits.logical_block_size,
983 PAGE_SIZE, bdev_logical_block_size(cached_bdev));
985 /* This also adjusts physical block size/min io size if needed */
986 blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev));
989 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
990 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
991 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
993 blk_queue_write_cache(q, true, true);
998 ida_simple_remove(&bcache_device_idx, idx);
1005 static void calc_cached_dev_sectors(struct cache_set *c)
1007 uint64_t sectors = 0;
1008 struct cached_dev *dc;
1010 list_for_each_entry(dc, &c->cached_devs, list)
1011 sectors += bdev_sectors(dc->bdev);
1013 c->cached_dev_sectors = sectors;
1016 #define BACKING_DEV_OFFLINE_TIMEOUT 5
1017 static int cached_dev_status_update(void *arg)
1019 struct cached_dev *dc = arg;
1020 struct request_queue *q;
1023 * If this delayed worker is stopping outside, directly quit here.
1024 * dc->io_disable might be set via sysfs interface, so check it
1027 while (!kthread_should_stop() && !dc->io_disable) {
1028 q = bdev_get_queue(dc->bdev);
1029 if (blk_queue_dying(q))
1030 dc->offline_seconds++;
1032 dc->offline_seconds = 0;
1034 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
1035 pr_err("%s: device offline for %d seconds\n",
1036 dc->backing_dev_name,
1037 BACKING_DEV_OFFLINE_TIMEOUT);
1038 pr_err("%s: disable I/O request due to backing device offline\n",
1040 dc->io_disable = true;
1041 /* let others know earlier that io_disable is true */
1043 bcache_device_stop(&dc->disk);
1046 schedule_timeout_interruptible(HZ);
1049 wait_for_kthread_stop();
1054 int bch_cached_dev_run(struct cached_dev *dc)
1057 struct bcache_device *d = &dc->disk;
1058 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
1061 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
1062 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
1066 if (dc->io_disable) {
1067 pr_err("I/O disabled on cached dev %s\n",
1068 dc->backing_dev_name);
1073 if (atomic_xchg(&dc->running, 1)) {
1074 pr_info("cached dev %s is running already\n",
1075 dc->backing_dev_name);
1081 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
1084 closure_init_stack(&cl);
1086 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
1087 bch_write_bdev_super(dc, &cl);
1092 bd_link_disk_holder(dc->bdev, dc->disk.disk);
1094 * won't show up in the uevent file, use udevadm monitor -e instead
1095 * only class / kset properties are persistent
1097 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1099 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1100 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1101 &d->kobj, "bcache")) {
1102 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1107 dc->status_update_thread = kthread_run(cached_dev_status_update,
1108 dc, "bcache_status_update");
1109 if (IS_ERR(dc->status_update_thread)) {
1110 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1121 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1122 * work dc->writeback_rate_update is running. Wait until the routine
1123 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1124 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1125 * seconds, give up waiting here and continue to cancel it too.
1127 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1129 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1132 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1136 schedule_timeout_interruptible(1);
1137 } while (time_out > 0);
1140 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1142 cancel_delayed_work_sync(&dc->writeback_rate_update);
1145 static void cached_dev_detach_finish(struct work_struct *w)
1147 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1149 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1150 BUG_ON(refcount_read(&dc->count));
1153 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1154 cancel_writeback_rate_update_dwork(dc);
1156 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1157 kthread_stop(dc->writeback_thread);
1158 dc->writeback_thread = NULL;
1161 mutex_lock(&bch_register_lock);
1163 calc_cached_dev_sectors(dc->disk.c);
1164 bcache_device_detach(&dc->disk);
1165 list_move(&dc->list, &uncached_devices);
1167 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1168 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1170 mutex_unlock(&bch_register_lock);
1172 pr_info("Caching disabled for %s\n", dc->backing_dev_name);
1174 /* Drop ref we took in cached_dev_detach() */
1175 closure_put(&dc->disk.cl);
1178 void bch_cached_dev_detach(struct cached_dev *dc)
1180 lockdep_assert_held(&bch_register_lock);
1182 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1185 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1189 * Block the device from being closed and freed until we're finished
1192 closure_get(&dc->disk.cl);
1194 bch_writeback_queue(dc);
1199 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1202 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1203 struct uuid_entry *u;
1204 struct cached_dev *exist_dc, *t;
1207 if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
1208 (!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
1212 pr_err("Can't attach %s: already attached\n",
1213 dc->backing_dev_name);
1217 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1218 pr_err("Can't attach %s: shutting down\n",
1219 dc->backing_dev_name);
1223 if (dc->sb.block_size < c->cache->sb.block_size) {
1225 pr_err("Couldn't attach %s: block size less than set's block size\n",
1226 dc->backing_dev_name);
1230 /* Check whether already attached */
1231 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1232 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1233 pr_err("Tried to attach %s but duplicate UUID already attached\n",
1234 dc->backing_dev_name);
1240 u = uuid_find(c, dc->sb.uuid);
1243 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1244 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1245 memcpy(u->uuid, invalid_uuid, 16);
1246 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1251 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1252 pr_err("Couldn't find uuid for %s in set\n",
1253 dc->backing_dev_name);
1257 u = uuid_find_empty(c);
1259 pr_err("Not caching %s, no room for UUID\n",
1260 dc->backing_dev_name);
1266 * Deadlocks since we're called via sysfs...
1267 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1270 if (bch_is_zero(u->uuid, 16)) {
1273 closure_init_stack(&cl);
1275 memcpy(u->uuid, dc->sb.uuid, 16);
1276 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1277 u->first_reg = u->last_reg = rtime;
1280 memcpy(dc->sb.set_uuid, c->set_uuid, 16);
1281 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1283 bch_write_bdev_super(dc, &cl);
1286 u->last_reg = rtime;
1290 bcache_device_attach(&dc->disk, c, u - c->uuids);
1291 list_move(&dc->list, &c->cached_devs);
1292 calc_cached_dev_sectors(c);
1295 * dc->c must be set before dc->count != 0 - paired with the mb in
1299 refcount_set(&dc->count, 1);
1301 /* Block writeback thread, but spawn it */
1302 down_write(&dc->writeback_lock);
1303 if (bch_cached_dev_writeback_start(dc)) {
1304 up_write(&dc->writeback_lock);
1305 pr_err("Couldn't start writeback facilities for %s\n",
1306 dc->disk.disk->disk_name);
1310 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1311 atomic_set(&dc->has_dirty, 1);
1312 bch_writeback_queue(dc);
1315 bch_sectors_dirty_init(&dc->disk);
1317 ret = bch_cached_dev_run(dc);
1318 if (ret && (ret != -EBUSY)) {
1319 up_write(&dc->writeback_lock);
1321 * bch_register_lock is held, bcache_device_stop() is not
1322 * able to be directly called. The kthread and kworker
1323 * created previously in bch_cached_dev_writeback_start()
1324 * have to be stopped manually here.
1326 kthread_stop(dc->writeback_thread);
1327 cancel_writeback_rate_update_dwork(dc);
1328 pr_err("Couldn't run cached device %s\n",
1329 dc->backing_dev_name);
1333 bcache_device_link(&dc->disk, c, "bdev");
1334 atomic_inc(&c->attached_dev_nr);
1336 if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
1337 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1338 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1339 set_disk_ro(dc->disk.disk, 1);
1342 /* Allow the writeback thread to proceed */
1343 up_write(&dc->writeback_lock);
1345 pr_info("Caching %s as %s on set %pU\n",
1346 dc->backing_dev_name,
1347 dc->disk.disk->disk_name,
1348 dc->disk.c->set_uuid);
1352 /* when dc->disk.kobj released */
1353 void bch_cached_dev_release(struct kobject *kobj)
1355 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1358 module_put(THIS_MODULE);
1361 static void cached_dev_free(struct closure *cl)
1363 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1365 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1366 cancel_writeback_rate_update_dwork(dc);
1368 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1369 kthread_stop(dc->writeback_thread);
1370 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1371 kthread_stop(dc->status_update_thread);
1373 mutex_lock(&bch_register_lock);
1375 if (atomic_read(&dc->running))
1376 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1377 bcache_device_free(&dc->disk);
1378 list_del(&dc->list);
1380 mutex_unlock(&bch_register_lock);
1383 put_page(virt_to_page(dc->sb_disk));
1385 if (!IS_ERR_OR_NULL(dc->bdev))
1386 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1388 wake_up(&unregister_wait);
1390 kobject_put(&dc->disk.kobj);
1393 static void cached_dev_flush(struct closure *cl)
1395 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1396 struct bcache_device *d = &dc->disk;
1398 mutex_lock(&bch_register_lock);
1399 bcache_device_unlink(d);
1400 mutex_unlock(&bch_register_lock);
1402 bch_cache_accounting_destroy(&dc->accounting);
1403 kobject_del(&d->kobj);
1405 continue_at(cl, cached_dev_free, system_wq);
1408 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1412 struct request_queue *q = bdev_get_queue(dc->bdev);
1414 __module_get(THIS_MODULE);
1415 INIT_LIST_HEAD(&dc->list);
1416 closure_init(&dc->disk.cl, NULL);
1417 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1418 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1419 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1420 sema_init(&dc->sb_write_mutex, 1);
1421 INIT_LIST_HEAD(&dc->io_lru);
1422 spin_lock_init(&dc->io_lock);
1423 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1425 dc->sequential_cutoff = 4 << 20;
1427 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1428 list_add(&io->lru, &dc->io_lru);
1429 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1432 dc->disk.stripe_size = q->limits.io_opt >> 9;
1434 if (dc->disk.stripe_size)
1435 dc->partial_stripes_expensive =
1436 q->limits.raid_partial_stripes_expensive;
1438 ret = bcache_device_init(&dc->disk, block_size,
1439 bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
1440 dc->bdev, &bcache_cached_ops);
1444 blk_queue_io_opt(dc->disk.disk->queue,
1445 max(queue_io_opt(dc->disk.disk->queue), queue_io_opt(q)));
1447 atomic_set(&dc->io_errors, 0);
1448 dc->io_disable = false;
1449 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1450 /* default to auto */
1451 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1453 bch_cached_dev_request_init(dc);
1454 bch_cached_dev_writeback_init(dc);
1458 /* Cached device - bcache superblock */
1460 static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1461 struct block_device *bdev,
1462 struct cached_dev *dc)
1464 const char *err = "cannot allocate memory";
1465 struct cache_set *c;
1468 bdevname(bdev, dc->backing_dev_name);
1469 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1471 dc->bdev->bd_holder = dc;
1472 dc->sb_disk = sb_disk;
1474 if (cached_dev_init(dc, sb->block_size << 9))
1477 err = "error creating kobject";
1478 if (kobject_add(&dc->disk.kobj, bdev_kobj(bdev), "bcache"))
1480 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1483 pr_info("registered backing device %s\n", dc->backing_dev_name);
1485 list_add(&dc->list, &uncached_devices);
1486 /* attach to a matched cache set if it exists */
1487 list_for_each_entry(c, &bch_cache_sets, list)
1488 bch_cached_dev_attach(dc, c, NULL);
1490 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1491 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1492 err = "failed to run cached device";
1493 ret = bch_cached_dev_run(dc);
1500 pr_notice("error %s: %s\n", dc->backing_dev_name, err);
1501 bcache_device_stop(&dc->disk);
1505 /* Flash only volumes */
1507 /* When d->kobj released */
1508 void bch_flash_dev_release(struct kobject *kobj)
1510 struct bcache_device *d = container_of(kobj, struct bcache_device,
1515 static void flash_dev_free(struct closure *cl)
1517 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1519 mutex_lock(&bch_register_lock);
1520 atomic_long_sub(bcache_dev_sectors_dirty(d),
1521 &d->c->flash_dev_dirty_sectors);
1522 bcache_device_free(d);
1523 mutex_unlock(&bch_register_lock);
1524 kobject_put(&d->kobj);
1527 static void flash_dev_flush(struct closure *cl)
1529 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1531 mutex_lock(&bch_register_lock);
1532 bcache_device_unlink(d);
1533 mutex_unlock(&bch_register_lock);
1534 kobject_del(&d->kobj);
1535 continue_at(cl, flash_dev_free, system_wq);
1538 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1540 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1545 closure_init(&d->cl, NULL);
1546 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1548 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1550 if (bcache_device_init(d, block_bytes(c->cache), u->sectors,
1551 NULL, &bcache_flash_ops))
1554 bcache_device_attach(d, c, u - c->uuids);
1555 bch_sectors_dirty_init(d);
1556 bch_flash_dev_request_init(d);
1559 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1562 bcache_device_link(d, c, "volume");
1564 if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
1565 pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
1566 pr_err("Please update to the latest bcache-tools to create the cache device\n");
1567 set_disk_ro(d->disk, 1);
1572 kobject_put(&d->kobj);
1576 static int flash_devs_run(struct cache_set *c)
1579 struct uuid_entry *u;
1582 u < c->uuids + c->nr_uuids && !ret;
1584 if (UUID_FLASH_ONLY(u))
1585 ret = flash_dev_run(c, u);
1590 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1592 struct uuid_entry *u;
1594 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1597 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1600 u = uuid_find_empty(c);
1602 pr_err("Can't create volume, no room for UUID\n");
1606 get_random_bytes(u->uuid, 16);
1607 memset(u->label, 0, 32);
1608 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1610 SET_UUID_FLASH_ONLY(u, 1);
1611 u->sectors = size >> 9;
1615 return flash_dev_run(c, u);
1618 bool bch_cached_dev_error(struct cached_dev *dc)
1620 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1623 dc->io_disable = true;
1624 /* make others know io_disable is true earlier */
1627 pr_err("stop %s: too many IO errors on backing device %s\n",
1628 dc->disk.disk->disk_name, dc->backing_dev_name);
1630 bcache_device_stop(&dc->disk);
1637 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1639 struct va_format vaf;
1642 if (c->on_error != ON_ERROR_PANIC &&
1643 test_bit(CACHE_SET_STOPPING, &c->flags))
1646 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1647 pr_info("CACHE_SET_IO_DISABLE already set\n");
1650 * XXX: we can be called from atomic context
1651 * acquire_console_sem();
1654 va_start(args, fmt);
1659 pr_err("error on %pU: %pV, disabling caching\n",
1664 if (c->on_error == ON_ERROR_PANIC)
1665 panic("panic forced after error\n");
1667 bch_cache_set_unregister(c);
1671 /* When c->kobj released */
1672 void bch_cache_set_release(struct kobject *kobj)
1674 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1677 module_put(THIS_MODULE);
1680 static void cache_set_free(struct closure *cl)
1682 struct cache_set *c = container_of(cl, struct cache_set, cl);
1685 debugfs_remove(c->debug);
1687 bch_open_buckets_free(c);
1688 bch_btree_cache_free(c);
1689 bch_journal_free(c);
1691 mutex_lock(&bch_register_lock);
1692 bch_bset_sort_state_free(&c->sort);
1693 free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
1699 kobject_put(&ca->kobj);
1703 if (c->moving_gc_wq)
1704 destroy_workqueue(c->moving_gc_wq);
1705 bioset_exit(&c->bio_split);
1706 mempool_exit(&c->fill_iter);
1707 mempool_exit(&c->bio_meta);
1708 mempool_exit(&c->search);
1712 mutex_unlock(&bch_register_lock);
1714 pr_info("Cache set %pU unregistered\n", c->set_uuid);
1715 wake_up(&unregister_wait);
1717 closure_debug_destroy(&c->cl);
1718 kobject_put(&c->kobj);
1721 static void cache_set_flush(struct closure *cl)
1723 struct cache_set *c = container_of(cl, struct cache_set, caching);
1724 struct cache *ca = c->cache;
1727 bch_cache_accounting_destroy(&c->accounting);
1729 kobject_put(&c->internal);
1730 kobject_del(&c->kobj);
1732 if (!IS_ERR_OR_NULL(c->gc_thread))
1733 kthread_stop(c->gc_thread);
1735 if (!IS_ERR_OR_NULL(c->root))
1736 list_add(&c->root->list, &c->btree_cache);
1739 * Avoid flushing cached nodes if cache set is retiring
1740 * due to too many I/O errors detected.
1742 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1743 list_for_each_entry(b, &c->btree_cache, list) {
1744 mutex_lock(&b->write_lock);
1745 if (btree_node_dirty(b))
1746 __bch_btree_node_write(b, NULL);
1747 mutex_unlock(&b->write_lock);
1750 if (ca->alloc_thread)
1751 kthread_stop(ca->alloc_thread);
1753 if (c->journal.cur) {
1754 cancel_delayed_work_sync(&c->journal.work);
1755 /* flush last journal entry if needed */
1756 c->journal.work.work.func(&c->journal.work.work);
1763 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1764 * cache set is unregistering due to too many I/O errors. In this condition,
1765 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1766 * value and whether the broken cache has dirty data:
1768 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1769 * BCH_CACHED_STOP_AUTO 0 NO
1770 * BCH_CACHED_STOP_AUTO 1 YES
1771 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1772 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1774 * The expected behavior is, if stop_when_cache_set_failed is configured to
1775 * "auto" via sysfs interface, the bcache device will not be stopped if the
1776 * backing device is clean on the broken cache device.
1778 static void conditional_stop_bcache_device(struct cache_set *c,
1779 struct bcache_device *d,
1780 struct cached_dev *dc)
1782 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1783 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1784 d->disk->disk_name, c->set_uuid);
1785 bcache_device_stop(d);
1786 } else if (atomic_read(&dc->has_dirty)) {
1788 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1789 * and dc->has_dirty == 1
1791 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1792 d->disk->disk_name);
1794 * There might be a small time gap that cache set is
1795 * released but bcache device is not. Inside this time
1796 * gap, regular I/O requests will directly go into
1797 * backing device as no cache set attached to. This
1798 * behavior may also introduce potential inconsistence
1799 * data in writeback mode while cache is dirty.
1800 * Therefore before calling bcache_device_stop() due
1801 * to a broken cache device, dc->io_disable should be
1802 * explicitly set to true.
1804 dc->io_disable = true;
1805 /* make others know io_disable is true earlier */
1807 bcache_device_stop(d);
1810 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1811 * and dc->has_dirty == 0
1813 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1814 d->disk->disk_name);
1818 static void __cache_set_unregister(struct closure *cl)
1820 struct cache_set *c = container_of(cl, struct cache_set, caching);
1821 struct cached_dev *dc;
1822 struct bcache_device *d;
1825 mutex_lock(&bch_register_lock);
1827 for (i = 0; i < c->devices_max_used; i++) {
1832 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1833 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1834 dc = container_of(d, struct cached_dev, disk);
1835 bch_cached_dev_detach(dc);
1836 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1837 conditional_stop_bcache_device(c, d, dc);
1839 bcache_device_stop(d);
1843 mutex_unlock(&bch_register_lock);
1845 continue_at(cl, cache_set_flush, system_wq);
1848 void bch_cache_set_stop(struct cache_set *c)
1850 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1851 /* closure_fn set to __cache_set_unregister() */
1852 closure_queue(&c->caching);
1855 void bch_cache_set_unregister(struct cache_set *c)
1857 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1858 bch_cache_set_stop(c);
1861 #define alloc_meta_bucket_pages(gfp, sb) \
1862 ((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
1864 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1867 struct cache *ca = container_of(sb, struct cache, sb);
1868 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1873 __module_get(THIS_MODULE);
1874 closure_init(&c->cl, NULL);
1875 set_closure_fn(&c->cl, cache_set_free, system_wq);
1877 closure_init(&c->caching, &c->cl);
1878 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1880 /* Maybe create continue_at_noreturn() and use it here? */
1881 closure_set_stopped(&c->cl);
1882 closure_put(&c->cl);
1884 kobject_init(&c->kobj, &bch_cache_set_ktype);
1885 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1887 bch_cache_accounting_init(&c->accounting, &c->cl);
1889 memcpy(c->set_uuid, sb->set_uuid, 16);
1893 c->bucket_bits = ilog2(sb->bucket_size);
1894 c->block_bits = ilog2(sb->block_size);
1895 c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
1896 c->devices_max_used = 0;
1897 atomic_set(&c->attached_dev_nr, 0);
1898 c->btree_pages = meta_bucket_pages(sb);
1899 if (c->btree_pages > BTREE_MAX_PAGES)
1900 c->btree_pages = max_t(int, c->btree_pages / 4,
1903 sema_init(&c->sb_write_mutex, 1);
1904 mutex_init(&c->bucket_lock);
1905 init_waitqueue_head(&c->btree_cache_wait);
1906 spin_lock_init(&c->btree_cannibalize_lock);
1907 init_waitqueue_head(&c->bucket_wait);
1908 init_waitqueue_head(&c->gc_wait);
1909 sema_init(&c->uuid_write_mutex, 1);
1911 spin_lock_init(&c->btree_gc_time.lock);
1912 spin_lock_init(&c->btree_split_time.lock);
1913 spin_lock_init(&c->btree_read_time.lock);
1915 bch_moving_init_cache_set(c);
1917 INIT_LIST_HEAD(&c->list);
1918 INIT_LIST_HEAD(&c->cached_devs);
1919 INIT_LIST_HEAD(&c->btree_cache);
1920 INIT_LIST_HEAD(&c->btree_cache_freeable);
1921 INIT_LIST_HEAD(&c->btree_cache_freed);
1922 INIT_LIST_HEAD(&c->data_buckets);
1924 iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size + 1) *
1925 sizeof(struct btree_iter_set);
1927 c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
1931 if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
1934 if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
1935 sizeof(struct bbio) +
1936 sizeof(struct bio_vec) * meta_bucket_pages(sb)))
1939 if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
1942 if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1943 BIOSET_NEED_RESCUER))
1946 c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
1950 c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
1951 if (!c->moving_gc_wq)
1954 if (bch_journal_alloc(c))
1957 if (bch_btree_cache_alloc(c))
1960 if (bch_open_buckets_alloc(c))
1963 if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1966 c->congested_read_threshold_us = 2000;
1967 c->congested_write_threshold_us = 20000;
1968 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1969 c->idle_max_writeback_rate_enabled = 1;
1970 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1974 bch_cache_set_unregister(c);
1978 static int run_cache_set(struct cache_set *c)
1980 const char *err = "cannot allocate memory";
1981 struct cached_dev *dc, *t;
1982 struct cache *ca = c->cache;
1985 struct journal_replay *l;
1987 closure_init_stack(&cl);
1989 c->nbuckets = ca->sb.nbuckets;
1992 if (CACHE_SYNC(&c->cache->sb)) {
1996 err = "cannot allocate memory for journal";
1997 if (bch_journal_read(c, &journal))
2000 pr_debug("btree_journal_read() done\n");
2002 err = "no journal entries found";
2003 if (list_empty(&journal))
2006 j = &list_entry(journal.prev, struct journal_replay, list)->j;
2008 err = "IO error reading priorities";
2009 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
2013 * If prio_read() fails it'll call cache_set_error and we'll
2014 * tear everything down right away, but if we perhaps checked
2015 * sooner we could avoid journal replay.
2020 err = "bad btree root";
2021 if (__bch_btree_ptr_invalid(c, k))
2024 err = "error reading btree root";
2025 c->root = bch_btree_node_get(c, NULL, k,
2028 if (IS_ERR_OR_NULL(c->root))
2031 list_del_init(&c->root->list);
2032 rw_unlock(true, c->root);
2034 err = uuid_read(c, j, &cl);
2038 err = "error in recovery";
2039 if (bch_btree_check(c))
2042 bch_journal_mark(c, &journal);
2043 bch_initial_gc_finish(c);
2044 pr_debug("btree_check() done\n");
2047 * bcache_journal_next() can't happen sooner, or
2048 * btree_gc_finish() will give spurious errors about last_gc >
2049 * gc_gen - this is a hack but oh well.
2051 bch_journal_next(&c->journal);
2053 err = "error starting allocator thread";
2054 if (bch_cache_allocator_start(ca))
2058 * First place it's safe to allocate: btree_check() and
2059 * btree_gc_finish() have to run before we have buckets to
2060 * allocate, and bch_bucket_alloc_set() might cause a journal
2061 * entry to be written so bcache_journal_next() has to be called
2064 * If the uuids were in the old format we have to rewrite them
2065 * before the next journal entry is written:
2067 if (j->version < BCACHE_JSET_VERSION_UUID)
2070 err = "bcache: replay journal failed";
2071 if (bch_journal_replay(c, &journal))
2076 pr_notice("invalidating existing data\n");
2077 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2078 2, SB_JOURNAL_BUCKETS);
2080 for (j = 0; j < ca->sb.keys; j++)
2081 ca->sb.d[j] = ca->sb.first_bucket + j;
2083 bch_initial_gc_finish(c);
2085 err = "error starting allocator thread";
2086 if (bch_cache_allocator_start(ca))
2089 mutex_lock(&c->bucket_lock);
2090 bch_prio_write(ca, true);
2091 mutex_unlock(&c->bucket_lock);
2093 err = "cannot allocate new UUID bucket";
2094 if (__uuid_write(c))
2097 err = "cannot allocate new btree root";
2098 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
2099 if (IS_ERR_OR_NULL(c->root))
2102 mutex_lock(&c->root->write_lock);
2103 bkey_copy_key(&c->root->key, &MAX_KEY);
2104 bch_btree_node_write(c->root, &cl);
2105 mutex_unlock(&c->root->write_lock);
2107 bch_btree_set_root(c->root);
2108 rw_unlock(true, c->root);
2111 * We don't want to write the first journal entry until
2112 * everything is set up - fortunately journal entries won't be
2113 * written until the SET_CACHE_SYNC() here:
2115 SET_CACHE_SYNC(&c->cache->sb, true);
2117 bch_journal_next(&c->journal);
2118 bch_journal_meta(c, &cl);
2121 err = "error starting gc thread";
2122 if (bch_gc_thread_start(c))
2126 c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
2127 bcache_write_super(c);
2129 if (bch_has_feature_obso_large_bucket(&c->cache->sb))
2130 pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
2132 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2133 bch_cached_dev_attach(dc, c, NULL);
2137 set_bit(CACHE_SET_RUNNING, &c->flags);
2140 while (!list_empty(&journal)) {
2141 l = list_first_entry(&journal, struct journal_replay, list);
2148 bch_cache_set_error(c, "%s", err);
2153 static const char *register_cache_set(struct cache *ca)
2156 const char *err = "cannot allocate memory";
2157 struct cache_set *c;
2159 list_for_each_entry(c, &bch_cache_sets, list)
2160 if (!memcmp(c->set_uuid, ca->sb.set_uuid, 16)) {
2162 return "duplicate cache set member";
2167 c = bch_cache_set_alloc(&ca->sb);
2171 err = "error creating kobject";
2172 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->set_uuid) ||
2173 kobject_add(&c->internal, &c->kobj, "internal"))
2176 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2179 bch_debug_init_cache_set(c);
2181 list_add(&c->list, &bch_cache_sets);
2183 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2184 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2185 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2188 kobject_get(&ca->kobj);
2190 ca->set->cache = ca;
2192 err = "failed to run cache set";
2193 if (run_cache_set(c) < 0)
2198 bch_cache_set_unregister(c);
2204 /* When ca->kobj released */
2205 void bch_cache_release(struct kobject *kobj)
2207 struct cache *ca = container_of(kobj, struct cache, kobj);
2211 BUG_ON(ca->set->cache != ca);
2212 ca->set->cache = NULL;
2215 free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
2216 kfree(ca->prio_buckets);
2219 free_heap(&ca->heap);
2220 free_fifo(&ca->free_inc);
2222 for (i = 0; i < RESERVE_NR; i++)
2223 free_fifo(&ca->free[i]);
2226 put_page(virt_to_page(ca->sb_disk));
2228 if (!IS_ERR_OR_NULL(ca->bdev))
2229 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2232 module_put(THIS_MODULE);
2235 static int cache_alloc(struct cache *ca)
2238 size_t btree_buckets;
2241 const char *err = NULL;
2243 __module_get(THIS_MODULE);
2244 kobject_init(&ca->kobj, &bch_cache_ktype);
2246 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2249 * when ca->sb.njournal_buckets is not zero, journal exists,
2250 * and in bch_journal_replay(), tree node may split,
2251 * so bucket of RESERVE_BTREE type is needed,
2252 * the worst situation is all journal buckets are valid journal,
2253 * and all the keys need to replay,
2254 * so the number of RESERVE_BTREE type buckets should be as much
2255 * as journal buckets
2257 btree_buckets = ca->sb.njournal_buckets ?: 8;
2258 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2261 err = "ca->sb.nbuckets is too small";
2265 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2267 err = "ca->free[RESERVE_BTREE] alloc failed";
2268 goto err_btree_alloc;
2271 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2273 err = "ca->free[RESERVE_PRIO] alloc failed";
2274 goto err_prio_alloc;
2277 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2278 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2279 goto err_movinggc_alloc;
2282 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2283 err = "ca->free[RESERVE_NONE] alloc failed";
2284 goto err_none_alloc;
2287 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2288 err = "ca->free_inc alloc failed";
2289 goto err_free_inc_alloc;
2292 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2293 err = "ca->heap alloc failed";
2294 goto err_heap_alloc;
2297 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2300 err = "ca->buckets alloc failed";
2301 goto err_buckets_alloc;
2304 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2305 prio_buckets(ca), 2),
2307 if (!ca->prio_buckets) {
2308 err = "ca->prio_buckets alloc failed";
2309 goto err_prio_buckets_alloc;
2312 ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
2313 if (!ca->disk_buckets) {
2314 err = "ca->disk_buckets alloc failed";
2315 goto err_disk_buckets_alloc;
2318 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2320 for_each_bucket(b, ca)
2321 atomic_set(&b->pin, 0);
2324 err_disk_buckets_alloc:
2325 kfree(ca->prio_buckets);
2326 err_prio_buckets_alloc:
2329 free_heap(&ca->heap);
2331 free_fifo(&ca->free_inc);
2333 free_fifo(&ca->free[RESERVE_NONE]);
2335 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2337 free_fifo(&ca->free[RESERVE_PRIO]);
2339 free_fifo(&ca->free[RESERVE_BTREE]);
2342 module_put(THIS_MODULE);
2344 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2348 static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2349 struct block_device *bdev, struct cache *ca)
2351 const char *err = NULL; /* must be set for any error case */
2354 bdevname(bdev, ca->cache_dev_name);
2355 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2357 ca->bdev->bd_holder = ca;
2358 ca->sb_disk = sb_disk;
2360 if (blk_queue_discard(bdev_get_queue(bdev)))
2361 ca->discard = CACHE_DISCARD(&ca->sb);
2363 ret = cache_alloc(ca);
2366 * If we failed here, it means ca->kobj is not initialized yet,
2367 * kobject_put() won't be called and there is no chance to
2368 * call blkdev_put() to bdev in bch_cache_release(). So we
2369 * explicitly call blkdev_put() here.
2371 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2373 err = "cache_alloc(): -ENOMEM";
2374 else if (ret == -EPERM)
2375 err = "cache_alloc(): cache device is too small";
2377 err = "cache_alloc(): unknown error";
2381 if (kobject_add(&ca->kobj, bdev_kobj(bdev), "bcache")) {
2382 err = "error calling kobject_add";
2387 mutex_lock(&bch_register_lock);
2388 err = register_cache_set(ca);
2389 mutex_unlock(&bch_register_lock);
2396 pr_info("registered cache device %s\n", ca->cache_dev_name);
2399 kobject_put(&ca->kobj);
2403 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2408 /* Global interfaces/init */
2410 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2411 const char *buffer, size_t size);
2412 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2413 struct kobj_attribute *attr,
2414 const char *buffer, size_t size);
2416 kobj_attribute_write(register, register_bcache);
2417 kobj_attribute_write(register_quiet, register_bcache);
2418 kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2420 static bool bch_is_open_backing(dev_t dev)
2422 struct cache_set *c, *tc;
2423 struct cached_dev *dc, *t;
2425 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2426 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2427 if (dc->bdev->bd_dev == dev)
2429 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2430 if (dc->bdev->bd_dev == dev)
2435 static bool bch_is_open_cache(dev_t dev)
2437 struct cache_set *c, *tc;
2439 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2440 struct cache *ca = c->cache;
2442 if (ca->bdev->bd_dev == dev)
2449 static bool bch_is_open(dev_t dev)
2451 return bch_is_open_cache(dev) || bch_is_open_backing(dev);
2454 struct async_reg_args {
2455 struct delayed_work reg_work;
2457 struct cache_sb *sb;
2458 struct cache_sb_disk *sb_disk;
2459 struct block_device *bdev;
2462 static void register_bdev_worker(struct work_struct *work)
2465 struct async_reg_args *args =
2466 container_of(work, struct async_reg_args, reg_work.work);
2467 struct cached_dev *dc;
2469 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2472 put_page(virt_to_page(args->sb_disk));
2473 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2477 mutex_lock(&bch_register_lock);
2478 if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
2480 mutex_unlock(&bch_register_lock);
2484 pr_info("error %s: fail to register backing device\n",
2489 module_put(THIS_MODULE);
2492 static void register_cache_worker(struct work_struct *work)
2495 struct async_reg_args *args =
2496 container_of(work, struct async_reg_args, reg_work.work);
2499 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2502 put_page(virt_to_page(args->sb_disk));
2503 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2507 /* blkdev_put() will be called in bch_cache_release() */
2508 if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
2513 pr_info("error %s: fail to register cache device\n",
2518 module_put(THIS_MODULE);
2521 static void register_device_async(struct async_reg_args *args)
2523 if (SB_IS_BDEV(args->sb))
2524 INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
2526 INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
2528 /* 10 jiffies is enough for a delay */
2529 queue_delayed_work(system_wq, &args->reg_work, 10);
2532 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2533 const char *buffer, size_t size)
2537 struct cache_sb *sb;
2538 struct cache_sb_disk *sb_disk;
2539 struct block_device *bdev;
2541 bool async_registration = false;
2543 #ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
2544 async_registration = true;
2548 err = "failed to reference bcache module";
2549 if (!try_module_get(THIS_MODULE))
2552 /* For latest state of bcache_is_reboot */
2554 err = "bcache is in reboot";
2555 if (bcache_is_reboot)
2556 goto out_module_put;
2559 err = "cannot allocate memory";
2560 path = kstrndup(buffer, size, GFP_KERNEL);
2562 goto out_module_put;
2564 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2569 err = "failed to open device";
2570 bdev = blkdev_get_by_path(strim(path),
2571 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2574 if (bdev == ERR_PTR(-EBUSY)) {
2577 mutex_lock(&bch_register_lock);
2578 if (lookup_bdev(strim(path), &dev) == 0 &&
2580 err = "device already registered";
2582 err = "device busy";
2583 mutex_unlock(&bch_register_lock);
2584 if (attr == &ksysfs_register_quiet)
2590 err = "failed to set blocksize";
2591 if (set_blocksize(bdev, 4096))
2592 goto out_blkdev_put;
2594 err = read_super(sb, bdev, &sb_disk);
2596 goto out_blkdev_put;
2598 err = "failed to register device";
2600 if (async_registration) {
2601 /* register in asynchronous way */
2602 struct async_reg_args *args =
2603 kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2607 err = "cannot allocate memory";
2608 goto out_put_sb_page;
2613 args->sb_disk = sb_disk;
2615 register_device_async(args);
2616 /* No wait and returns to user space */
2620 if (SB_IS_BDEV(sb)) {
2621 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2624 goto out_put_sb_page;
2626 mutex_lock(&bch_register_lock);
2627 ret = register_bdev(sb, sb_disk, bdev, dc);
2628 mutex_unlock(&bch_register_lock);
2629 /* blkdev_put() will be called in cached_dev_free() */
2633 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2636 goto out_put_sb_page;
2638 /* blkdev_put() will be called in bch_cache_release() */
2639 if (register_cache(sb, sb_disk, bdev, ca) != 0)
2646 module_put(THIS_MODULE);
2651 put_page(virt_to_page(sb_disk));
2653 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2660 module_put(THIS_MODULE);
2662 pr_info("error %s: %s\n", path?path:"", err);
2668 struct list_head list;
2669 struct cached_dev *dc;
2672 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2673 struct kobj_attribute *attr,
2677 LIST_HEAD(pending_devs);
2679 struct cached_dev *dc, *tdc;
2680 struct pdev *pdev, *tpdev;
2681 struct cache_set *c, *tc;
2683 mutex_lock(&bch_register_lock);
2684 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2685 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2689 list_add(&pdev->list, &pending_devs);
2692 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2693 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2694 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2695 char *set_uuid = c->set_uuid;
2697 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2698 list_del(&pdev->list);
2704 mutex_unlock(&bch_register_lock);
2706 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2707 pr_info("delete pdev %p\n", pdev);
2708 list_del(&pdev->list);
2709 bcache_device_stop(&pdev->dc->disk);
2716 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2718 if (bcache_is_reboot)
2721 if (code == SYS_DOWN ||
2723 code == SYS_POWER_OFF) {
2725 unsigned long start = jiffies;
2726 bool stopped = false;
2728 struct cache_set *c, *tc;
2729 struct cached_dev *dc, *tdc;
2731 mutex_lock(&bch_register_lock);
2733 if (bcache_is_reboot)
2736 /* New registration is rejected since now */
2737 bcache_is_reboot = true;
2739 * Make registering caller (if there is) on other CPU
2740 * core know bcache_is_reboot set to true earlier
2744 if (list_empty(&bch_cache_sets) &&
2745 list_empty(&uncached_devices))
2748 mutex_unlock(&bch_register_lock);
2750 pr_info("Stopping all devices:\n");
2753 * The reason bch_register_lock is not held to call
2754 * bch_cache_set_stop() and bcache_device_stop() is to
2755 * avoid potential deadlock during reboot, because cache
2756 * set or bcache device stopping process will acqurie
2757 * bch_register_lock too.
2759 * We are safe here because bcache_is_reboot sets to
2760 * true already, register_bcache() will reject new
2761 * registration now. bcache_is_reboot also makes sure
2762 * bcache_reboot() won't be re-entered on by other thread,
2763 * so there is no race in following list iteration by
2764 * list_for_each_entry_safe().
2766 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2767 bch_cache_set_stop(c);
2769 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2770 bcache_device_stop(&dc->disk);
2774 * Give an early chance for other kthreads and
2775 * kworkers to stop themselves
2779 /* What's a condition variable? */
2781 long timeout = start + 10 * HZ - jiffies;
2783 mutex_lock(&bch_register_lock);
2784 stopped = list_empty(&bch_cache_sets) &&
2785 list_empty(&uncached_devices);
2787 if (timeout < 0 || stopped)
2790 prepare_to_wait(&unregister_wait, &wait,
2791 TASK_UNINTERRUPTIBLE);
2793 mutex_unlock(&bch_register_lock);
2794 schedule_timeout(timeout);
2797 finish_wait(&unregister_wait, &wait);
2800 pr_info("All devices stopped\n");
2802 pr_notice("Timeout waiting for devices to be closed\n");
2804 mutex_unlock(&bch_register_lock);
2810 static struct notifier_block reboot = {
2811 .notifier_call = bcache_reboot,
2812 .priority = INT_MAX, /* before any real devices */
2815 static void bcache_exit(void)
2820 kobject_put(bcache_kobj);
2822 destroy_workqueue(bcache_wq);
2824 destroy_workqueue(bch_journal_wq);
2826 destroy_workqueue(bch_flush_wq);
2830 unregister_blkdev(bcache_major, "bcache");
2831 unregister_reboot_notifier(&reboot);
2832 mutex_destroy(&bch_register_lock);
2835 /* Check and fixup module parameters */
2836 static void check_module_parameters(void)
2838 if (bch_cutoff_writeback_sync == 0)
2839 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2840 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2841 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2842 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2843 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2846 if (bch_cutoff_writeback == 0)
2847 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2848 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2849 pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2850 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2851 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2854 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2855 pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2856 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2857 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2861 static int __init bcache_init(void)
2863 static const struct attribute *files[] = {
2864 &ksysfs_register.attr,
2865 &ksysfs_register_quiet.attr,
2866 &ksysfs_pendings_cleanup.attr,
2870 check_module_parameters();
2872 mutex_init(&bch_register_lock);
2873 init_waitqueue_head(&unregister_wait);
2874 register_reboot_notifier(&reboot);
2876 bcache_major = register_blkdev(0, "bcache");
2877 if (bcache_major < 0) {
2878 unregister_reboot_notifier(&reboot);
2879 mutex_destroy(&bch_register_lock);
2880 return bcache_major;
2883 if (bch_btree_init())
2886 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2891 * Let's not make this `WQ_MEM_RECLAIM` for the following reasons:
2893 * 1. It used `system_wq` before which also does no memory reclaim.
2894 * 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and
2895 * reduced throughput can be observed.
2897 * We still want to user our own queue to not congest the `system_wq`.
2899 bch_flush_wq = alloc_workqueue("bch_flush", 0, 0);
2903 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2904 if (!bch_journal_wq)
2907 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2911 if (bch_request_init() ||
2912 sysfs_create_files(bcache_kobj, files))
2916 closure_debug_init();
2918 bcache_is_reboot = false;
2929 module_exit(bcache_exit);
2930 module_init(bcache_init);
2932 module_param(bch_cutoff_writeback, uint, 0);
2933 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2935 module_param(bch_cutoff_writeback_sync, uint, 0);
2936 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2938 MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2939 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2940 MODULE_LICENSE("GPL");