1 // SPDX-License-Identifier: GPL-2.0
3 * bcache setup/teardown code, and some metadata io - read a superblock and
4 * figure out what to do with it.
6 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
7 * Copyright 2012 Google, Inc.
15 #include "writeback.h"
17 #include <linux/blkdev.h>
18 #include <linux/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 unsigned int bch_cutoff_writeback;
28 unsigned int bch_cutoff_writeback_sync;
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 static struct kobject *bcache_kobj;
41 struct mutex bch_register_lock;
42 bool bcache_is_reboot;
43 LIST_HEAD(bch_cache_sets);
44 static LIST_HEAD(uncached_devices);
46 static int bcache_major;
47 static DEFINE_IDA(bcache_device_idx);
48 static wait_queue_head_t unregister_wait;
49 struct workqueue_struct *bcache_wq;
50 struct workqueue_struct *bch_journal_wq;
53 #define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
54 /* limitation of partitions number on single bcache device */
55 #define BCACHE_MINORS 128
56 /* limitation of bcache devices number on single system */
57 #define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
61 static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
62 struct cache_sb_disk **res)
65 struct cache_sb_disk *s;
69 page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
70 SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
73 s = page_address(page) + offset_in_page(SB_OFFSET);
75 sb->offset = le64_to_cpu(s->offset);
76 sb->version = le64_to_cpu(s->version);
78 memcpy(sb->magic, s->magic, 16);
79 memcpy(sb->uuid, s->uuid, 16);
80 memcpy(sb->set_uuid, s->set_uuid, 16);
81 memcpy(sb->label, s->label, SB_LABEL_SIZE);
83 sb->flags = le64_to_cpu(s->flags);
84 sb->seq = le64_to_cpu(s->seq);
85 sb->last_mount = le32_to_cpu(s->last_mount);
86 sb->first_bucket = le16_to_cpu(s->first_bucket);
87 sb->keys = le16_to_cpu(s->keys);
89 for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
90 sb->d[i] = le64_to_cpu(s->d[i]);
92 pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u\n",
93 sb->version, sb->flags, sb->seq, sb->keys);
95 err = "Not a bcache superblock (bad offset)";
96 if (sb->offset != SB_SECTOR)
99 err = "Not a bcache superblock (bad magic)";
100 if (memcmp(sb->magic, bcache_magic, 16))
103 err = "Too many journal buckets";
104 if (sb->keys > SB_JOURNAL_BUCKETS)
107 err = "Bad checksum";
108 if (s->csum != csum_set(s))
112 if (bch_is_zero(sb->uuid, 16))
115 sb->block_size = le16_to_cpu(s->block_size);
117 err = "Superblock block size smaller than device block size";
118 if (sb->block_size << 9 < bdev_logical_block_size(bdev))
121 switch (sb->version) {
122 case BCACHE_SB_VERSION_BDEV:
123 sb->data_offset = BDEV_DATA_START_DEFAULT;
125 case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
126 sb->data_offset = le64_to_cpu(s->data_offset);
128 err = "Bad data offset";
129 if (sb->data_offset < BDEV_DATA_START_DEFAULT)
133 case BCACHE_SB_VERSION_CDEV:
134 case BCACHE_SB_VERSION_CDEV_WITH_UUID:
135 sb->nbuckets = le64_to_cpu(s->nbuckets);
136 sb->bucket_size = le16_to_cpu(s->bucket_size);
138 sb->nr_in_set = le16_to_cpu(s->nr_in_set);
139 sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
141 err = "Too many buckets";
142 if (sb->nbuckets > LONG_MAX)
145 err = "Not enough buckets";
146 if (sb->nbuckets < 1 << 7)
149 err = "Bad block/bucket size";
150 if (!is_power_of_2(sb->block_size) ||
151 sb->block_size > PAGE_SECTORS ||
152 !is_power_of_2(sb->bucket_size) ||
153 sb->bucket_size < PAGE_SECTORS)
156 err = "Invalid superblock: device too small";
157 if (get_capacity(bdev->bd_disk) <
158 sb->bucket_size * sb->nbuckets)
162 if (bch_is_zero(sb->set_uuid, 16))
165 err = "Bad cache device number in set";
166 if (!sb->nr_in_set ||
167 sb->nr_in_set <= sb->nr_this_dev ||
168 sb->nr_in_set > MAX_CACHES_PER_SET)
171 err = "Journal buckets not sequential";
172 for (i = 0; i < sb->keys; i++)
173 if (sb->d[i] != sb->first_bucket + i)
176 err = "Too many journal buckets";
177 if (sb->first_bucket + sb->keys > sb->nbuckets)
180 err = "Invalid superblock: first bucket comes before end of super";
181 if (sb->first_bucket * sb->bucket_size < 16)
186 err = "Unsupported superblock version";
190 sb->last_mount = (u32)ktime_get_real_seconds();
198 static void write_bdev_super_endio(struct bio *bio)
200 struct cached_dev *dc = bio->bi_private;
203 bch_count_backing_io_errors(dc, bio);
205 closure_put(&dc->sb_write);
208 static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
213 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
214 bio->bi_iter.bi_sector = SB_SECTOR;
215 __bio_add_page(bio, virt_to_page(out), SB_SIZE,
216 offset_in_page(out));
218 out->offset = cpu_to_le64(sb->offset);
219 out->version = cpu_to_le64(sb->version);
221 memcpy(out->uuid, sb->uuid, 16);
222 memcpy(out->set_uuid, sb->set_uuid, 16);
223 memcpy(out->label, sb->label, SB_LABEL_SIZE);
225 out->flags = cpu_to_le64(sb->flags);
226 out->seq = cpu_to_le64(sb->seq);
228 out->last_mount = cpu_to_le32(sb->last_mount);
229 out->first_bucket = cpu_to_le16(sb->first_bucket);
230 out->keys = cpu_to_le16(sb->keys);
232 for (i = 0; i < sb->keys; i++)
233 out->d[i] = cpu_to_le64(sb->d[i]);
235 out->csum = csum_set(out);
237 pr_debug("ver %llu, flags %llu, seq %llu\n",
238 sb->version, sb->flags, sb->seq);
243 static void bch_write_bdev_super_unlock(struct closure *cl)
245 struct cached_dev *dc = container_of(cl, struct cached_dev, sb_write);
247 up(&dc->sb_write_mutex);
250 void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
252 struct closure *cl = &dc->sb_write;
253 struct bio *bio = &dc->sb_bio;
255 down(&dc->sb_write_mutex);
256 closure_init(cl, parent);
258 bio_init(bio, dc->sb_bv, 1);
259 bio_set_dev(bio, dc->bdev);
260 bio->bi_end_io = write_bdev_super_endio;
261 bio->bi_private = dc;
264 /* I/O request sent to backing device */
265 __write_super(&dc->sb, dc->sb_disk, bio);
267 closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
270 static void write_super_endio(struct bio *bio)
272 struct cache *ca = bio->bi_private;
275 bch_count_io_errors(ca, bio->bi_status, 0,
276 "writing superblock");
277 closure_put(&ca->set->sb_write);
280 static void bcache_write_super_unlock(struct closure *cl)
282 struct cache_set *c = container_of(cl, struct cache_set, sb_write);
284 up(&c->sb_write_mutex);
287 void bcache_write_super(struct cache_set *c)
289 struct closure *cl = &c->sb_write;
293 down(&c->sb_write_mutex);
294 closure_init(cl, &c->cl);
298 for_each_cache(ca, c, i) {
299 struct bio *bio = &ca->sb_bio;
301 ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
302 ca->sb.seq = c->sb.seq;
303 ca->sb.last_mount = c->sb.last_mount;
305 SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
307 bio_init(bio, ca->sb_bv, 1);
308 bio_set_dev(bio, ca->bdev);
309 bio->bi_end_io = write_super_endio;
310 bio->bi_private = ca;
313 __write_super(&ca->sb, ca->sb_disk, bio);
316 closure_return_with_destructor(cl, bcache_write_super_unlock);
321 static void uuid_endio(struct bio *bio)
323 struct closure *cl = bio->bi_private;
324 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
326 cache_set_err_on(bio->bi_status, c, "accessing uuids");
327 bch_bbio_free(bio, c);
331 static void uuid_io_unlock(struct closure *cl)
333 struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
335 up(&c->uuid_write_mutex);
338 static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
339 struct bkey *k, struct closure *parent)
341 struct closure *cl = &c->uuid_write;
342 struct uuid_entry *u;
347 down(&c->uuid_write_mutex);
348 closure_init(cl, parent);
350 for (i = 0; i < KEY_PTRS(k); i++) {
351 struct bio *bio = bch_bbio_alloc(c);
353 bio->bi_opf = REQ_SYNC | REQ_META | op_flags;
354 bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
356 bio->bi_end_io = uuid_endio;
357 bio->bi_private = cl;
358 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
359 bch_bio_map(bio, c->uuids);
361 bch_submit_bbio(bio, c, k, i);
363 if (op != REQ_OP_WRITE)
367 bch_extent_to_text(buf, sizeof(buf), k);
368 pr_debug("%s UUIDs at %s\n", op == REQ_OP_WRITE ? "wrote" : "read", buf);
370 for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
371 if (!bch_is_zero(u->uuid, 16))
372 pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u\n",
373 u - c->uuids, u->uuid, u->label,
374 u->first_reg, u->last_reg, u->invalidated);
376 closure_return_with_destructor(cl, uuid_io_unlock);
379 static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
381 struct bkey *k = &j->uuid_bucket;
383 if (__bch_btree_ptr_invalid(c, k))
384 return "bad uuid pointer";
386 bkey_copy(&c->uuid_bucket, k);
387 uuid_io(c, REQ_OP_READ, 0, k, cl);
389 if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
390 struct uuid_entry_v0 *u0 = (void *) c->uuids;
391 struct uuid_entry *u1 = (void *) c->uuids;
397 * Since the new uuid entry is bigger than the old, we have to
398 * convert starting at the highest memory address and work down
399 * in order to do it in place
402 for (i = c->nr_uuids - 1;
405 memcpy(u1[i].uuid, u0[i].uuid, 16);
406 memcpy(u1[i].label, u0[i].label, 32);
408 u1[i].first_reg = u0[i].first_reg;
409 u1[i].last_reg = u0[i].last_reg;
410 u1[i].invalidated = u0[i].invalidated;
420 static int __uuid_write(struct cache_set *c)
426 closure_init_stack(&cl);
427 lockdep_assert_held(&bch_register_lock);
429 if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
432 SET_KEY_SIZE(&k.key, c->sb.bucket_size);
433 uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
436 /* Only one bucket used for uuid write */
437 ca = PTR_CACHE(c, &k.key, 0);
438 atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
440 bkey_copy(&c->uuid_bucket, &k.key);
445 int bch_uuid_write(struct cache_set *c)
447 int ret = __uuid_write(c);
450 bch_journal_meta(c, NULL);
455 static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
457 struct uuid_entry *u;
460 u < c->uuids + c->nr_uuids; u++)
461 if (!memcmp(u->uuid, uuid, 16))
467 static struct uuid_entry *uuid_find_empty(struct cache_set *c)
469 static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
471 return uuid_find(c, zero_uuid);
475 * Bucket priorities/gens:
477 * For each bucket, we store on disk its
481 * See alloc.c for an explanation of the gen. The priority is used to implement
482 * lru (and in the future other) cache replacement policies; for most purposes
483 * it's just an opaque integer.
485 * The gens and the priorities don't have a whole lot to do with each other, and
486 * it's actually the gens that must be written out at specific times - it's no
487 * big deal if the priorities don't get written, if we lose them we just reuse
488 * buckets in suboptimal order.
490 * On disk they're stored in a packed array, and in as many buckets are required
491 * to fit them all. The buckets we use to store them form a list; the journal
492 * header points to the first bucket, the first bucket points to the second
495 * This code is used by the allocation code; periodically (whenever it runs out
496 * of buckets to allocate from) the allocation code will invalidate some
497 * buckets, but it can't use those buckets until their new gens are safely on
501 static void prio_endio(struct bio *bio)
503 struct cache *ca = bio->bi_private;
505 cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
506 bch_bbio_free(bio, ca->set);
507 closure_put(&ca->prio);
510 static void prio_io(struct cache *ca, uint64_t bucket, int op,
511 unsigned long op_flags)
513 struct closure *cl = &ca->prio;
514 struct bio *bio = bch_bbio_alloc(ca->set);
516 closure_init_stack(cl);
518 bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
519 bio_set_dev(bio, ca->bdev);
520 bio->bi_iter.bi_size = bucket_bytes(ca);
522 bio->bi_end_io = prio_endio;
523 bio->bi_private = ca;
524 bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
525 bch_bio_map(bio, ca->disk_buckets);
527 closure_bio_submit(ca->set, bio, &ca->prio);
531 int bch_prio_write(struct cache *ca, bool wait)
537 pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n",
538 fifo_used(&ca->free[RESERVE_PRIO]),
539 fifo_used(&ca->free[RESERVE_NONE]),
540 fifo_used(&ca->free_inc));
543 * Pre-check if there are enough free buckets. In the non-blocking
544 * scenario it's better to fail early rather than starting to allocate
545 * buckets and do a cleanup later in case of failure.
548 size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
549 fifo_used(&ca->free[RESERVE_NONE]);
550 if (prio_buckets(ca) > avail)
554 closure_init_stack(&cl);
556 lockdep_assert_held(&ca->set->bucket_lock);
558 ca->disk_buckets->seq++;
560 atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
561 &ca->meta_sectors_written);
563 for (i = prio_buckets(ca) - 1; i >= 0; --i) {
565 struct prio_set *p = ca->disk_buckets;
566 struct bucket_disk *d = p->data;
567 struct bucket_disk *end = d + prios_per_bucket(ca);
569 for (b = ca->buckets + i * prios_per_bucket(ca);
570 b < ca->buckets + ca->sb.nbuckets && d < end;
572 d->prio = cpu_to_le16(b->prio);
576 p->next_bucket = ca->prio_buckets[i + 1];
577 p->magic = pset_magic(&ca->sb);
578 p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
580 bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
581 BUG_ON(bucket == -1);
583 mutex_unlock(&ca->set->bucket_lock);
584 prio_io(ca, bucket, REQ_OP_WRITE, 0);
585 mutex_lock(&ca->set->bucket_lock);
587 ca->prio_buckets[i] = bucket;
588 atomic_dec_bug(&ca->buckets[bucket].pin);
591 mutex_unlock(&ca->set->bucket_lock);
593 bch_journal_meta(ca->set, &cl);
596 mutex_lock(&ca->set->bucket_lock);
599 * Don't want the old priorities to get garbage collected until after we
600 * finish writing the new ones, and they're journalled
602 for (i = 0; i < prio_buckets(ca); i++) {
603 if (ca->prio_last_buckets[i])
604 __bch_bucket_free(ca,
605 &ca->buckets[ca->prio_last_buckets[i]]);
607 ca->prio_last_buckets[i] = ca->prio_buckets[i];
612 static int prio_read(struct cache *ca, uint64_t bucket)
614 struct prio_set *p = ca->disk_buckets;
615 struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
617 unsigned int bucket_nr = 0;
620 for (b = ca->buckets;
621 b < ca->buckets + ca->sb.nbuckets;
624 ca->prio_buckets[bucket_nr] = bucket;
625 ca->prio_last_buckets[bucket_nr] = bucket;
628 prio_io(ca, bucket, REQ_OP_READ, 0);
631 bch_crc64(&p->magic, bucket_bytes(ca) - 8)) {
632 pr_warn("bad csum reading priorities\n");
636 if (p->magic != pset_magic(&ca->sb)) {
637 pr_warn("bad magic reading priorities\n");
641 bucket = p->next_bucket;
645 b->prio = le16_to_cpu(d->prio);
646 b->gen = b->last_gc = d->gen;
656 static int open_dev(struct block_device *b, fmode_t mode)
658 struct bcache_device *d = b->bd_disk->private_data;
660 if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
667 static void release_dev(struct gendisk *b, fmode_t mode)
669 struct bcache_device *d = b->private_data;
674 static int ioctl_dev(struct block_device *b, fmode_t mode,
675 unsigned int cmd, unsigned long arg)
677 struct bcache_device *d = b->bd_disk->private_data;
679 return d->ioctl(d, mode, cmd, arg);
682 static const struct block_device_operations bcache_ops = {
684 .release = release_dev,
686 .owner = THIS_MODULE,
689 void bcache_device_stop(struct bcache_device *d)
691 if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
694 * - cached device: cached_dev_flush()
695 * - flash dev: flash_dev_flush()
697 closure_queue(&d->cl);
700 static void bcache_device_unlink(struct bcache_device *d)
702 lockdep_assert_held(&bch_register_lock);
704 if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
708 sysfs_remove_link(&d->c->kobj, d->name);
709 sysfs_remove_link(&d->kobj, "cache");
711 for_each_cache(ca, d->c, i)
712 bd_unlink_disk_holder(ca->bdev, d->disk);
716 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
723 for_each_cache(ca, d->c, i)
724 bd_link_disk_holder(ca->bdev, d->disk);
726 snprintf(d->name, BCACHEDEVNAME_SIZE,
727 "%s%u", name, d->id);
729 ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
731 pr_err("Couldn't create device -> cache set symlink\n");
733 ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
735 pr_err("Couldn't create cache set -> device symlink\n");
737 clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
740 static void bcache_device_detach(struct bcache_device *d)
742 lockdep_assert_held(&bch_register_lock);
744 atomic_dec(&d->c->attached_dev_nr);
746 if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
747 struct uuid_entry *u = d->c->uuids + d->id;
749 SET_UUID_FLASH_ONLY(u, 0);
750 memcpy(u->uuid, invalid_uuid, 16);
751 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
752 bch_uuid_write(d->c);
755 bcache_device_unlink(d);
757 d->c->devices[d->id] = NULL;
758 closure_put(&d->c->caching);
762 static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
769 if (id >= c->devices_max_used)
770 c->devices_max_used = id + 1;
772 closure_get(&c->caching);
775 static inline int first_minor_to_idx(int first_minor)
777 return (first_minor/BCACHE_MINORS);
780 static inline int idx_to_first_minor(int idx)
782 return (idx * BCACHE_MINORS);
785 static void bcache_device_free(struct bcache_device *d)
787 struct gendisk *disk = d->disk;
789 lockdep_assert_held(&bch_register_lock);
792 pr_info("%s stopped\n", disk->disk_name);
794 pr_err("bcache device (NULL gendisk) stopped\n");
797 bcache_device_detach(d);
800 bool disk_added = (disk->flags & GENHD_FL_UP) != 0;
806 blk_cleanup_queue(disk->queue);
808 ida_simple_remove(&bcache_device_idx,
809 first_minor_to_idx(disk->first_minor));
814 bioset_exit(&d->bio_split);
815 kvfree(d->full_dirty_stripes);
816 kvfree(d->stripe_sectors_dirty);
818 closure_debug_destroy(&d->cl);
821 static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
822 sector_t sectors, make_request_fn make_request_fn)
824 struct request_queue *q;
825 const size_t max_stripes = min_t(size_t, INT_MAX,
826 SIZE_MAX / sizeof(atomic_t));
831 d->stripe_size = 1 << 31;
833 d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
835 if (!d->nr_stripes || d->nr_stripes > max_stripes) {
836 pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)\n",
837 (unsigned int)d->nr_stripes);
841 n = d->nr_stripes * sizeof(atomic_t);
842 d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
843 if (!d->stripe_sectors_dirty)
846 n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
847 d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
848 if (!d->full_dirty_stripes)
851 idx = ida_simple_get(&bcache_device_idx, 0,
852 BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
856 if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
857 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
860 d->disk = alloc_disk(BCACHE_MINORS);
864 set_capacity(d->disk, sectors);
865 snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
867 d->disk->major = bcache_major;
868 d->disk->first_minor = idx_to_first_minor(idx);
869 d->disk->fops = &bcache_ops;
870 d->disk->private_data = d;
872 q = blk_alloc_queue(make_request_fn, NUMA_NO_NODE);
878 q->backing_dev_info->congested_data = d;
879 q->limits.max_hw_sectors = UINT_MAX;
880 q->limits.max_sectors = UINT_MAX;
881 q->limits.max_segment_size = UINT_MAX;
882 q->limits.max_segments = BIO_MAX_PAGES;
883 blk_queue_max_discard_sectors(q, UINT_MAX);
884 q->limits.discard_granularity = 512;
885 q->limits.io_min = block_size;
886 q->limits.logical_block_size = block_size;
887 q->limits.physical_block_size = block_size;
888 blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
889 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
890 blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
892 blk_queue_write_cache(q, true, true);
897 ida_simple_remove(&bcache_device_idx, idx);
904 static void calc_cached_dev_sectors(struct cache_set *c)
906 uint64_t sectors = 0;
907 struct cached_dev *dc;
909 list_for_each_entry(dc, &c->cached_devs, list)
910 sectors += bdev_sectors(dc->bdev);
912 c->cached_dev_sectors = sectors;
915 #define BACKING_DEV_OFFLINE_TIMEOUT 5
916 static int cached_dev_status_update(void *arg)
918 struct cached_dev *dc = arg;
919 struct request_queue *q;
922 * If this delayed worker is stopping outside, directly quit here.
923 * dc->io_disable might be set via sysfs interface, so check it
926 while (!kthread_should_stop() && !dc->io_disable) {
927 q = bdev_get_queue(dc->bdev);
928 if (blk_queue_dying(q))
929 dc->offline_seconds++;
931 dc->offline_seconds = 0;
933 if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
934 pr_err("%s: device offline for %d seconds\n",
935 dc->backing_dev_name,
936 BACKING_DEV_OFFLINE_TIMEOUT);
937 pr_err("%s: disable I/O request due to backing device offline\n",
939 dc->io_disable = true;
940 /* let others know earlier that io_disable is true */
942 bcache_device_stop(&dc->disk);
945 schedule_timeout_interruptible(HZ);
948 wait_for_kthread_stop();
953 int bch_cached_dev_run(struct cached_dev *dc)
955 struct bcache_device *d = &dc->disk;
956 char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
959 kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
960 kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
964 if (dc->io_disable) {
965 pr_err("I/O disabled on cached dev %s\n",
966 dc->backing_dev_name);
973 if (atomic_xchg(&dc->running, 1)) {
977 pr_info("cached dev %s is running already\n",
978 dc->backing_dev_name);
983 BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
986 closure_init_stack(&cl);
988 SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
989 bch_write_bdev_super(dc, &cl);
994 bd_link_disk_holder(dc->bdev, dc->disk.disk);
996 * won't show up in the uevent file, use udevadm monitor -e instead
997 * only class / kset properties are persistent
999 kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
1004 if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
1005 sysfs_create_link(&disk_to_dev(d->disk)->kobj,
1006 &d->kobj, "bcache")) {
1007 pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
1011 dc->status_update_thread = kthread_run(cached_dev_status_update,
1012 dc, "bcache_status_update");
1013 if (IS_ERR(dc->status_update_thread)) {
1014 pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
1021 * If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
1022 * work dc->writeback_rate_update is running. Wait until the routine
1023 * quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
1024 * cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
1025 * seconds, give up waiting here and continue to cancel it too.
1027 static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
1029 int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
1032 if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
1036 schedule_timeout_interruptible(1);
1037 } while (time_out > 0);
1040 pr_warn("give up waiting for dc->writeback_write_update to quit\n");
1042 cancel_delayed_work_sync(&dc->writeback_rate_update);
1045 static void cached_dev_detach_finish(struct work_struct *w)
1047 struct cached_dev *dc = container_of(w, struct cached_dev, detach);
1050 closure_init_stack(&cl);
1052 BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
1053 BUG_ON(refcount_read(&dc->count));
1056 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1057 cancel_writeback_rate_update_dwork(dc);
1059 if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
1060 kthread_stop(dc->writeback_thread);
1061 dc->writeback_thread = NULL;
1064 memset(&dc->sb.set_uuid, 0, 16);
1065 SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
1067 bch_write_bdev_super(dc, &cl);
1070 mutex_lock(&bch_register_lock);
1072 calc_cached_dev_sectors(dc->disk.c);
1073 bcache_device_detach(&dc->disk);
1074 list_move(&dc->list, &uncached_devices);
1076 clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
1077 clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
1079 mutex_unlock(&bch_register_lock);
1081 pr_info("Caching disabled for %s\n", dc->backing_dev_name);
1083 /* Drop ref we took in cached_dev_detach() */
1084 closure_put(&dc->disk.cl);
1087 void bch_cached_dev_detach(struct cached_dev *dc)
1089 lockdep_assert_held(&bch_register_lock);
1091 if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1094 if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
1098 * Block the device from being closed and freed until we're finished
1101 closure_get(&dc->disk.cl);
1103 bch_writeback_queue(dc);
1108 int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
1111 uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
1112 struct uuid_entry *u;
1113 struct cached_dev *exist_dc, *t;
1116 if ((set_uuid && memcmp(set_uuid, c->sb.set_uuid, 16)) ||
1117 (!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
1121 pr_err("Can't attach %s: already attached\n",
1122 dc->backing_dev_name);
1126 if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
1127 pr_err("Can't attach %s: shutting down\n",
1128 dc->backing_dev_name);
1132 if (dc->sb.block_size < c->sb.block_size) {
1134 pr_err("Couldn't attach %s: block size less than set's block size\n",
1135 dc->backing_dev_name);
1139 /* Check whether already attached */
1140 list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
1141 if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
1142 pr_err("Tried to attach %s but duplicate UUID already attached\n",
1143 dc->backing_dev_name);
1149 u = uuid_find(c, dc->sb.uuid);
1152 (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
1153 BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
1154 memcpy(u->uuid, invalid_uuid, 16);
1155 u->invalidated = cpu_to_le32((u32)ktime_get_real_seconds());
1160 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1161 pr_err("Couldn't find uuid for %s in set\n",
1162 dc->backing_dev_name);
1166 u = uuid_find_empty(c);
1168 pr_err("Not caching %s, no room for UUID\n",
1169 dc->backing_dev_name);
1175 * Deadlocks since we're called via sysfs...
1176 * sysfs_remove_file(&dc->kobj, &sysfs_attach);
1179 if (bch_is_zero(u->uuid, 16)) {
1182 closure_init_stack(&cl);
1184 memcpy(u->uuid, dc->sb.uuid, 16);
1185 memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
1186 u->first_reg = u->last_reg = rtime;
1189 memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
1190 SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
1192 bch_write_bdev_super(dc, &cl);
1195 u->last_reg = rtime;
1199 bcache_device_attach(&dc->disk, c, u - c->uuids);
1200 list_move(&dc->list, &c->cached_devs);
1201 calc_cached_dev_sectors(c);
1204 * dc->c must be set before dc->count != 0 - paired with the mb in
1208 refcount_set(&dc->count, 1);
1210 /* Block writeback thread, but spawn it */
1211 down_write(&dc->writeback_lock);
1212 if (bch_cached_dev_writeback_start(dc)) {
1213 up_write(&dc->writeback_lock);
1214 pr_err("Couldn't start writeback facilities for %s\n",
1215 dc->disk.disk->disk_name);
1219 if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
1220 atomic_set(&dc->has_dirty, 1);
1221 bch_writeback_queue(dc);
1224 bch_sectors_dirty_init(&dc->disk);
1226 ret = bch_cached_dev_run(dc);
1227 if (ret && (ret != -EBUSY)) {
1228 up_write(&dc->writeback_lock);
1230 * bch_register_lock is held, bcache_device_stop() is not
1231 * able to be directly called. The kthread and kworker
1232 * created previously in bch_cached_dev_writeback_start()
1233 * have to be stopped manually here.
1235 kthread_stop(dc->writeback_thread);
1236 cancel_writeback_rate_update_dwork(dc);
1237 pr_err("Couldn't run cached device %s\n",
1238 dc->backing_dev_name);
1242 bcache_device_link(&dc->disk, c, "bdev");
1243 atomic_inc(&c->attached_dev_nr);
1245 /* Allow the writeback thread to proceed */
1246 up_write(&dc->writeback_lock);
1248 pr_info("Caching %s as %s on set %pU\n",
1249 dc->backing_dev_name,
1250 dc->disk.disk->disk_name,
1251 dc->disk.c->sb.set_uuid);
1255 /* when dc->disk.kobj released */
1256 void bch_cached_dev_release(struct kobject *kobj)
1258 struct cached_dev *dc = container_of(kobj, struct cached_dev,
1261 module_put(THIS_MODULE);
1264 static void cached_dev_free(struct closure *cl)
1266 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1268 if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
1269 cancel_writeback_rate_update_dwork(dc);
1271 if (!IS_ERR_OR_NULL(dc->writeback_thread))
1272 kthread_stop(dc->writeback_thread);
1273 if (!IS_ERR_OR_NULL(dc->status_update_thread))
1274 kthread_stop(dc->status_update_thread);
1276 mutex_lock(&bch_register_lock);
1278 if (atomic_read(&dc->running))
1279 bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
1280 bcache_device_free(&dc->disk);
1281 list_del(&dc->list);
1283 mutex_unlock(&bch_register_lock);
1286 put_page(virt_to_page(dc->sb_disk));
1288 if (!IS_ERR_OR_NULL(dc->bdev))
1289 blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
1291 wake_up(&unregister_wait);
1293 kobject_put(&dc->disk.kobj);
1296 static void cached_dev_flush(struct closure *cl)
1298 struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
1299 struct bcache_device *d = &dc->disk;
1301 mutex_lock(&bch_register_lock);
1302 bcache_device_unlink(d);
1303 mutex_unlock(&bch_register_lock);
1305 bch_cache_accounting_destroy(&dc->accounting);
1306 kobject_del(&d->kobj);
1308 continue_at(cl, cached_dev_free, system_wq);
1311 static int cached_dev_init(struct cached_dev *dc, unsigned int block_size)
1315 struct request_queue *q = bdev_get_queue(dc->bdev);
1317 __module_get(THIS_MODULE);
1318 INIT_LIST_HEAD(&dc->list);
1319 closure_init(&dc->disk.cl, NULL);
1320 set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
1321 kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
1322 INIT_WORK(&dc->detach, cached_dev_detach_finish);
1323 sema_init(&dc->sb_write_mutex, 1);
1324 INIT_LIST_HEAD(&dc->io_lru);
1325 spin_lock_init(&dc->io_lock);
1326 bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
1328 dc->sequential_cutoff = 4 << 20;
1330 for (io = dc->io; io < dc->io + RECENT_IO; io++) {
1331 list_add(&io->lru, &dc->io_lru);
1332 hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
1335 dc->disk.stripe_size = q->limits.io_opt >> 9;
1337 if (dc->disk.stripe_size)
1338 dc->partial_stripes_expensive =
1339 q->limits.raid_partial_stripes_expensive;
1341 ret = bcache_device_init(&dc->disk, block_size,
1342 dc->bdev->bd_part->nr_sects - dc->sb.data_offset,
1343 cached_dev_make_request);
1347 dc->disk.disk->queue->backing_dev_info->ra_pages =
1348 max(dc->disk.disk->queue->backing_dev_info->ra_pages,
1349 q->backing_dev_info->ra_pages);
1351 atomic_set(&dc->io_errors, 0);
1352 dc->io_disable = false;
1353 dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
1354 /* default to auto */
1355 dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
1357 bch_cached_dev_request_init(dc);
1358 bch_cached_dev_writeback_init(dc);
1362 /* Cached device - bcache superblock */
1364 static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
1365 struct block_device *bdev,
1366 struct cached_dev *dc)
1368 const char *err = "cannot allocate memory";
1369 struct cache_set *c;
1372 bdevname(bdev, dc->backing_dev_name);
1373 memcpy(&dc->sb, sb, sizeof(struct cache_sb));
1375 dc->bdev->bd_holder = dc;
1376 dc->sb_disk = sb_disk;
1378 if (cached_dev_init(dc, sb->block_size << 9))
1381 err = "error creating kobject";
1382 if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
1385 if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
1388 pr_info("registered backing device %s\n", dc->backing_dev_name);
1390 list_add(&dc->list, &uncached_devices);
1391 /* attach to a matched cache set if it exists */
1392 list_for_each_entry(c, &bch_cache_sets, list)
1393 bch_cached_dev_attach(dc, c, NULL);
1395 if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
1396 BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
1397 err = "failed to run cached device";
1398 ret = bch_cached_dev_run(dc);
1405 pr_notice("error %s: %s\n", dc->backing_dev_name, err);
1406 bcache_device_stop(&dc->disk);
1410 /* Flash only volumes */
1412 /* When d->kobj released */
1413 void bch_flash_dev_release(struct kobject *kobj)
1415 struct bcache_device *d = container_of(kobj, struct bcache_device,
1420 static void flash_dev_free(struct closure *cl)
1422 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1424 mutex_lock(&bch_register_lock);
1425 atomic_long_sub(bcache_dev_sectors_dirty(d),
1426 &d->c->flash_dev_dirty_sectors);
1427 bcache_device_free(d);
1428 mutex_unlock(&bch_register_lock);
1429 kobject_put(&d->kobj);
1432 static void flash_dev_flush(struct closure *cl)
1434 struct bcache_device *d = container_of(cl, struct bcache_device, cl);
1436 mutex_lock(&bch_register_lock);
1437 bcache_device_unlink(d);
1438 mutex_unlock(&bch_register_lock);
1439 kobject_del(&d->kobj);
1440 continue_at(cl, flash_dev_free, system_wq);
1443 static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
1445 struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
1450 closure_init(&d->cl, NULL);
1451 set_closure_fn(&d->cl, flash_dev_flush, system_wq);
1453 kobject_init(&d->kobj, &bch_flash_dev_ktype);
1455 if (bcache_device_init(d, block_bytes(c), u->sectors,
1456 flash_dev_make_request))
1459 bcache_device_attach(d, c, u - c->uuids);
1460 bch_sectors_dirty_init(d);
1461 bch_flash_dev_request_init(d);
1464 if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
1467 bcache_device_link(d, c, "volume");
1471 kobject_put(&d->kobj);
1475 static int flash_devs_run(struct cache_set *c)
1478 struct uuid_entry *u;
1481 u < c->uuids + c->nr_uuids && !ret;
1483 if (UUID_FLASH_ONLY(u))
1484 ret = flash_dev_run(c, u);
1489 int bch_flash_dev_create(struct cache_set *c, uint64_t size)
1491 struct uuid_entry *u;
1493 if (test_bit(CACHE_SET_STOPPING, &c->flags))
1496 if (!test_bit(CACHE_SET_RUNNING, &c->flags))
1499 u = uuid_find_empty(c);
1501 pr_err("Can't create volume, no room for UUID\n");
1505 get_random_bytes(u->uuid, 16);
1506 memset(u->label, 0, 32);
1507 u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
1509 SET_UUID_FLASH_ONLY(u, 1);
1510 u->sectors = size >> 9;
1514 return flash_dev_run(c, u);
1517 bool bch_cached_dev_error(struct cached_dev *dc)
1519 if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
1522 dc->io_disable = true;
1523 /* make others know io_disable is true earlier */
1526 pr_err("stop %s: too many IO errors on backing device %s\n",
1527 dc->disk.disk->disk_name, dc->backing_dev_name);
1529 bcache_device_stop(&dc->disk);
1536 bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
1538 struct va_format vaf;
1541 if (c->on_error != ON_ERROR_PANIC &&
1542 test_bit(CACHE_SET_STOPPING, &c->flags))
1545 if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
1546 pr_info("CACHE_SET_IO_DISABLE already set\n");
1549 * XXX: we can be called from atomic context
1550 * acquire_console_sem();
1553 va_start(args, fmt);
1558 pr_err("error on %pU: %pV, disabling caching\n",
1559 c->sb.set_uuid, &vaf);
1563 if (c->on_error == ON_ERROR_PANIC)
1564 panic("panic forced after error\n");
1566 bch_cache_set_unregister(c);
1570 /* When c->kobj released */
1571 void bch_cache_set_release(struct kobject *kobj)
1573 struct cache_set *c = container_of(kobj, struct cache_set, kobj);
1576 module_put(THIS_MODULE);
1579 static void cache_set_free(struct closure *cl)
1581 struct cache_set *c = container_of(cl, struct cache_set, cl);
1585 debugfs_remove(c->debug);
1587 bch_open_buckets_free(c);
1588 bch_btree_cache_free(c);
1589 bch_journal_free(c);
1591 mutex_lock(&bch_register_lock);
1592 for_each_cache(ca, c, i)
1595 c->cache[ca->sb.nr_this_dev] = NULL;
1596 kobject_put(&ca->kobj);
1599 bch_bset_sort_state_free(&c->sort);
1600 free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
1602 if (c->moving_gc_wq)
1603 destroy_workqueue(c->moving_gc_wq);
1604 bioset_exit(&c->bio_split);
1605 mempool_exit(&c->fill_iter);
1606 mempool_exit(&c->bio_meta);
1607 mempool_exit(&c->search);
1611 mutex_unlock(&bch_register_lock);
1613 pr_info("Cache set %pU unregistered\n", c->sb.set_uuid);
1614 wake_up(&unregister_wait);
1616 closure_debug_destroy(&c->cl);
1617 kobject_put(&c->kobj);
1620 static void cache_set_flush(struct closure *cl)
1622 struct cache_set *c = container_of(cl, struct cache_set, caching);
1627 bch_cache_accounting_destroy(&c->accounting);
1629 kobject_put(&c->internal);
1630 kobject_del(&c->kobj);
1632 if (!IS_ERR_OR_NULL(c->gc_thread))
1633 kthread_stop(c->gc_thread);
1635 if (!IS_ERR_OR_NULL(c->root))
1636 list_add(&c->root->list, &c->btree_cache);
1639 * Avoid flushing cached nodes if cache set is retiring
1640 * due to too many I/O errors detected.
1642 if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1643 list_for_each_entry(b, &c->btree_cache, list) {
1644 mutex_lock(&b->write_lock);
1645 if (btree_node_dirty(b))
1646 __bch_btree_node_write(b, NULL);
1647 mutex_unlock(&b->write_lock);
1650 for_each_cache(ca, c, i)
1651 if (ca->alloc_thread)
1652 kthread_stop(ca->alloc_thread);
1654 if (c->journal.cur) {
1655 cancel_delayed_work_sync(&c->journal.work);
1656 /* flush last journal entry if needed */
1657 c->journal.work.work.func(&c->journal.work.work);
1664 * This function is only called when CACHE_SET_IO_DISABLE is set, which means
1665 * cache set is unregistering due to too many I/O errors. In this condition,
1666 * the bcache device might be stopped, it depends on stop_when_cache_set_failed
1667 * value and whether the broken cache has dirty data:
1669 * dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
1670 * BCH_CACHED_STOP_AUTO 0 NO
1671 * BCH_CACHED_STOP_AUTO 1 YES
1672 * BCH_CACHED_DEV_STOP_ALWAYS 0 YES
1673 * BCH_CACHED_DEV_STOP_ALWAYS 1 YES
1675 * The expected behavior is, if stop_when_cache_set_failed is configured to
1676 * "auto" via sysfs interface, the bcache device will not be stopped if the
1677 * backing device is clean on the broken cache device.
1679 static void conditional_stop_bcache_device(struct cache_set *c,
1680 struct bcache_device *d,
1681 struct cached_dev *dc)
1683 if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
1684 pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
1685 d->disk->disk_name, c->sb.set_uuid);
1686 bcache_device_stop(d);
1687 } else if (atomic_read(&dc->has_dirty)) {
1689 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1690 * and dc->has_dirty == 1
1692 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
1693 d->disk->disk_name);
1695 * There might be a small time gap that cache set is
1696 * released but bcache device is not. Inside this time
1697 * gap, regular I/O requests will directly go into
1698 * backing device as no cache set attached to. This
1699 * behavior may also introduce potential inconsistence
1700 * data in writeback mode while cache is dirty.
1701 * Therefore before calling bcache_device_stop() due
1702 * to a broken cache device, dc->io_disable should be
1703 * explicitly set to true.
1705 dc->io_disable = true;
1706 /* make others know io_disable is true earlier */
1708 bcache_device_stop(d);
1711 * dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
1712 * and dc->has_dirty == 0
1714 pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
1715 d->disk->disk_name);
1719 static void __cache_set_unregister(struct closure *cl)
1721 struct cache_set *c = container_of(cl, struct cache_set, caching);
1722 struct cached_dev *dc;
1723 struct bcache_device *d;
1726 mutex_lock(&bch_register_lock);
1728 for (i = 0; i < c->devices_max_used; i++) {
1733 if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
1734 test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
1735 dc = container_of(d, struct cached_dev, disk);
1736 bch_cached_dev_detach(dc);
1737 if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
1738 conditional_stop_bcache_device(c, d, dc);
1740 bcache_device_stop(d);
1744 mutex_unlock(&bch_register_lock);
1746 continue_at(cl, cache_set_flush, system_wq);
1749 void bch_cache_set_stop(struct cache_set *c)
1751 if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
1752 /* closure_fn set to __cache_set_unregister() */
1753 closure_queue(&c->caching);
1756 void bch_cache_set_unregister(struct cache_set *c)
1758 set_bit(CACHE_SET_UNREGISTERING, &c->flags);
1759 bch_cache_set_stop(c);
1762 #define alloc_bucket_pages(gfp, c) \
1763 ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
1765 struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
1768 struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
1773 __module_get(THIS_MODULE);
1774 closure_init(&c->cl, NULL);
1775 set_closure_fn(&c->cl, cache_set_free, system_wq);
1777 closure_init(&c->caching, &c->cl);
1778 set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
1780 /* Maybe create continue_at_noreturn() and use it here? */
1781 closure_set_stopped(&c->cl);
1782 closure_put(&c->cl);
1784 kobject_init(&c->kobj, &bch_cache_set_ktype);
1785 kobject_init(&c->internal, &bch_cache_set_internal_ktype);
1787 bch_cache_accounting_init(&c->accounting, &c->cl);
1789 memcpy(c->sb.set_uuid, sb->set_uuid, 16);
1790 c->sb.block_size = sb->block_size;
1791 c->sb.bucket_size = sb->bucket_size;
1792 c->sb.nr_in_set = sb->nr_in_set;
1793 c->sb.last_mount = sb->last_mount;
1794 c->bucket_bits = ilog2(sb->bucket_size);
1795 c->block_bits = ilog2(sb->block_size);
1796 c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
1797 c->devices_max_used = 0;
1798 atomic_set(&c->attached_dev_nr, 0);
1799 c->btree_pages = bucket_pages(c);
1800 if (c->btree_pages > BTREE_MAX_PAGES)
1801 c->btree_pages = max_t(int, c->btree_pages / 4,
1804 sema_init(&c->sb_write_mutex, 1);
1805 mutex_init(&c->bucket_lock);
1806 init_waitqueue_head(&c->btree_cache_wait);
1807 spin_lock_init(&c->btree_cannibalize_lock);
1808 init_waitqueue_head(&c->bucket_wait);
1809 init_waitqueue_head(&c->gc_wait);
1810 sema_init(&c->uuid_write_mutex, 1);
1812 spin_lock_init(&c->btree_gc_time.lock);
1813 spin_lock_init(&c->btree_split_time.lock);
1814 spin_lock_init(&c->btree_read_time.lock);
1816 bch_moving_init_cache_set(c);
1818 INIT_LIST_HEAD(&c->list);
1819 INIT_LIST_HEAD(&c->cached_devs);
1820 INIT_LIST_HEAD(&c->btree_cache);
1821 INIT_LIST_HEAD(&c->btree_cache_freeable);
1822 INIT_LIST_HEAD(&c->btree_cache_freed);
1823 INIT_LIST_HEAD(&c->data_buckets);
1825 iter_size = (sb->bucket_size / sb->block_size + 1) *
1826 sizeof(struct btree_iter_set);
1828 if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) ||
1829 mempool_init_slab_pool(&c->search, 32, bch_search_cache) ||
1830 mempool_init_kmalloc_pool(&c->bio_meta, 2,
1831 sizeof(struct bbio) + sizeof(struct bio_vec) *
1833 mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
1834 bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
1835 BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) ||
1836 !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
1837 !(c->moving_gc_wq = alloc_workqueue("bcache_gc",
1838 WQ_MEM_RECLAIM, 0)) ||
1839 bch_journal_alloc(c) ||
1840 bch_btree_cache_alloc(c) ||
1841 bch_open_buckets_alloc(c) ||
1842 bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
1845 c->congested_read_threshold_us = 2000;
1846 c->congested_write_threshold_us = 20000;
1847 c->error_limit = DEFAULT_IO_ERROR_LIMIT;
1848 c->idle_max_writeback_rate_enabled = 1;
1849 WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
1853 bch_cache_set_unregister(c);
1857 static int run_cache_set(struct cache_set *c)
1859 const char *err = "cannot allocate memory";
1860 struct cached_dev *dc, *t;
1865 struct journal_replay *l;
1867 closure_init_stack(&cl);
1869 for_each_cache(ca, c, i)
1870 c->nbuckets += ca->sb.nbuckets;
1873 if (CACHE_SYNC(&c->sb)) {
1877 err = "cannot allocate memory for journal";
1878 if (bch_journal_read(c, &journal))
1881 pr_debug("btree_journal_read() done\n");
1883 err = "no journal entries found";
1884 if (list_empty(&journal))
1887 j = &list_entry(journal.prev, struct journal_replay, list)->j;
1889 err = "IO error reading priorities";
1890 for_each_cache(ca, c, i) {
1891 if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
1896 * If prio_read() fails it'll call cache_set_error and we'll
1897 * tear everything down right away, but if we perhaps checked
1898 * sooner we could avoid journal replay.
1903 err = "bad btree root";
1904 if (__bch_btree_ptr_invalid(c, k))
1907 err = "error reading btree root";
1908 c->root = bch_btree_node_get(c, NULL, k,
1911 if (IS_ERR_OR_NULL(c->root))
1914 list_del_init(&c->root->list);
1915 rw_unlock(true, c->root);
1917 err = uuid_read(c, j, &cl);
1921 err = "error in recovery";
1922 if (bch_btree_check(c))
1925 bch_journal_mark(c, &journal);
1926 bch_initial_gc_finish(c);
1927 pr_debug("btree_check() done\n");
1930 * bcache_journal_next() can't happen sooner, or
1931 * btree_gc_finish() will give spurious errors about last_gc >
1932 * gc_gen - this is a hack but oh well.
1934 bch_journal_next(&c->journal);
1936 err = "error starting allocator thread";
1937 for_each_cache(ca, c, i)
1938 if (bch_cache_allocator_start(ca))
1942 * First place it's safe to allocate: btree_check() and
1943 * btree_gc_finish() have to run before we have buckets to
1944 * allocate, and bch_bucket_alloc_set() might cause a journal
1945 * entry to be written so bcache_journal_next() has to be called
1948 * If the uuids were in the old format we have to rewrite them
1949 * before the next journal entry is written:
1951 if (j->version < BCACHE_JSET_VERSION_UUID)
1954 err = "bcache: replay journal failed";
1955 if (bch_journal_replay(c, &journal))
1958 pr_notice("invalidating existing data\n");
1960 for_each_cache(ca, c, i) {
1963 ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
1964 2, SB_JOURNAL_BUCKETS);
1966 for (j = 0; j < ca->sb.keys; j++)
1967 ca->sb.d[j] = ca->sb.first_bucket + j;
1970 bch_initial_gc_finish(c);
1972 err = "error starting allocator thread";
1973 for_each_cache(ca, c, i)
1974 if (bch_cache_allocator_start(ca))
1977 mutex_lock(&c->bucket_lock);
1978 for_each_cache(ca, c, i)
1979 bch_prio_write(ca, true);
1980 mutex_unlock(&c->bucket_lock);
1982 err = "cannot allocate new UUID bucket";
1983 if (__uuid_write(c))
1986 err = "cannot allocate new btree root";
1987 c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
1988 if (IS_ERR_OR_NULL(c->root))
1991 mutex_lock(&c->root->write_lock);
1992 bkey_copy_key(&c->root->key, &MAX_KEY);
1993 bch_btree_node_write(c->root, &cl);
1994 mutex_unlock(&c->root->write_lock);
1996 bch_btree_set_root(c->root);
1997 rw_unlock(true, c->root);
2000 * We don't want to write the first journal entry until
2001 * everything is set up - fortunately journal entries won't be
2002 * written until the SET_CACHE_SYNC() here:
2004 SET_CACHE_SYNC(&c->sb, true);
2006 bch_journal_next(&c->journal);
2007 bch_journal_meta(c, &cl);
2010 err = "error starting gc thread";
2011 if (bch_gc_thread_start(c))
2015 c->sb.last_mount = (u32)ktime_get_real_seconds();
2016 bcache_write_super(c);
2018 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2019 bch_cached_dev_attach(dc, c, NULL);
2023 set_bit(CACHE_SET_RUNNING, &c->flags);
2026 while (!list_empty(&journal)) {
2027 l = list_first_entry(&journal, struct journal_replay, list);
2034 bch_cache_set_error(c, "%s", err);
2039 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
2041 return ca->sb.block_size == c->sb.block_size &&
2042 ca->sb.bucket_size == c->sb.bucket_size &&
2043 ca->sb.nr_in_set == c->sb.nr_in_set;
2046 static const char *register_cache_set(struct cache *ca)
2049 const char *err = "cannot allocate memory";
2050 struct cache_set *c;
2052 list_for_each_entry(c, &bch_cache_sets, list)
2053 if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
2054 if (c->cache[ca->sb.nr_this_dev])
2055 return "duplicate cache set member";
2057 if (!can_attach_cache(ca, c))
2058 return "cache sb does not match set";
2060 if (!CACHE_SYNC(&ca->sb))
2061 SET_CACHE_SYNC(&c->sb, false);
2066 c = bch_cache_set_alloc(&ca->sb);
2070 err = "error creating kobject";
2071 if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
2072 kobject_add(&c->internal, &c->kobj, "internal"))
2075 if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
2078 bch_debug_init_cache_set(c);
2080 list_add(&c->list, &bch_cache_sets);
2082 sprintf(buf, "cache%i", ca->sb.nr_this_dev);
2083 if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
2084 sysfs_create_link(&c->kobj, &ca->kobj, buf))
2087 if (ca->sb.seq > c->sb.seq) {
2088 c->sb.version = ca->sb.version;
2089 memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
2090 c->sb.flags = ca->sb.flags;
2091 c->sb.seq = ca->sb.seq;
2092 pr_debug("set version = %llu\n", c->sb.version);
2095 kobject_get(&ca->kobj);
2097 ca->set->cache[ca->sb.nr_this_dev] = ca;
2098 c->cache_by_alloc[c->caches_loaded++] = ca;
2100 if (c->caches_loaded == c->sb.nr_in_set) {
2101 err = "failed to run cache set";
2102 if (run_cache_set(c) < 0)
2108 bch_cache_set_unregister(c);
2114 /* When ca->kobj released */
2115 void bch_cache_release(struct kobject *kobj)
2117 struct cache *ca = container_of(kobj, struct cache, kobj);
2121 BUG_ON(ca->set->cache[ca->sb.nr_this_dev] != ca);
2122 ca->set->cache[ca->sb.nr_this_dev] = NULL;
2125 free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
2126 kfree(ca->prio_buckets);
2129 free_heap(&ca->heap);
2130 free_fifo(&ca->free_inc);
2132 for (i = 0; i < RESERVE_NR; i++)
2133 free_fifo(&ca->free[i]);
2136 put_page(virt_to_page(ca->sb_disk));
2138 if (!IS_ERR_OR_NULL(ca->bdev))
2139 blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2142 module_put(THIS_MODULE);
2145 static int cache_alloc(struct cache *ca)
2148 size_t btree_buckets;
2151 const char *err = NULL;
2153 __module_get(THIS_MODULE);
2154 kobject_init(&ca->kobj, &bch_cache_ktype);
2156 bio_init(&ca->journal.bio, ca->journal.bio.bi_inline_vecs, 8);
2159 * when ca->sb.njournal_buckets is not zero, journal exists,
2160 * and in bch_journal_replay(), tree node may split,
2161 * so bucket of RESERVE_BTREE type is needed,
2162 * the worst situation is all journal buckets are valid journal,
2163 * and all the keys need to replay,
2164 * so the number of RESERVE_BTREE type buckets should be as much
2165 * as journal buckets
2167 btree_buckets = ca->sb.njournal_buckets ?: 8;
2168 free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
2171 err = "ca->sb.nbuckets is too small";
2175 if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
2177 err = "ca->free[RESERVE_BTREE] alloc failed";
2178 goto err_btree_alloc;
2181 if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
2183 err = "ca->free[RESERVE_PRIO] alloc failed";
2184 goto err_prio_alloc;
2187 if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
2188 err = "ca->free[RESERVE_MOVINGGC] alloc failed";
2189 goto err_movinggc_alloc;
2192 if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
2193 err = "ca->free[RESERVE_NONE] alloc failed";
2194 goto err_none_alloc;
2197 if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
2198 err = "ca->free_inc alloc failed";
2199 goto err_free_inc_alloc;
2202 if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
2203 err = "ca->heap alloc failed";
2204 goto err_heap_alloc;
2207 ca->buckets = vzalloc(array_size(sizeof(struct bucket),
2210 err = "ca->buckets alloc failed";
2211 goto err_buckets_alloc;
2214 ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
2215 prio_buckets(ca), 2),
2217 if (!ca->prio_buckets) {
2218 err = "ca->prio_buckets alloc failed";
2219 goto err_prio_buckets_alloc;
2222 ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca);
2223 if (!ca->disk_buckets) {
2224 err = "ca->disk_buckets alloc failed";
2225 goto err_disk_buckets_alloc;
2228 ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
2230 for_each_bucket(b, ca)
2231 atomic_set(&b->pin, 0);
2234 err_disk_buckets_alloc:
2235 kfree(ca->prio_buckets);
2236 err_prio_buckets_alloc:
2239 free_heap(&ca->heap);
2241 free_fifo(&ca->free_inc);
2243 free_fifo(&ca->free[RESERVE_NONE]);
2245 free_fifo(&ca->free[RESERVE_MOVINGGC]);
2247 free_fifo(&ca->free[RESERVE_PRIO]);
2249 free_fifo(&ca->free[RESERVE_BTREE]);
2252 module_put(THIS_MODULE);
2254 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2258 static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
2259 struct block_device *bdev, struct cache *ca)
2261 const char *err = NULL; /* must be set for any error case */
2264 bdevname(bdev, ca->cache_dev_name);
2265 memcpy(&ca->sb, sb, sizeof(struct cache_sb));
2267 ca->bdev->bd_holder = ca;
2268 ca->sb_disk = sb_disk;
2270 if (blk_queue_discard(bdev_get_queue(bdev)))
2271 ca->discard = CACHE_DISCARD(&ca->sb);
2273 ret = cache_alloc(ca);
2276 * If we failed here, it means ca->kobj is not initialized yet,
2277 * kobject_put() won't be called and there is no chance to
2278 * call blkdev_put() to bdev in bch_cache_release(). So we
2279 * explicitly call blkdev_put() here.
2281 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2283 err = "cache_alloc(): -ENOMEM";
2284 else if (ret == -EPERM)
2285 err = "cache_alloc(): cache device is too small";
2287 err = "cache_alloc(): unknown error";
2291 if (kobject_add(&ca->kobj,
2292 &part_to_dev(bdev->bd_part)->kobj,
2294 err = "error calling kobject_add";
2299 mutex_lock(&bch_register_lock);
2300 err = register_cache_set(ca);
2301 mutex_unlock(&bch_register_lock);
2308 pr_info("registered cache device %s\n", ca->cache_dev_name);
2311 kobject_put(&ca->kobj);
2315 pr_notice("error %s: %s\n", ca->cache_dev_name, err);
2320 /* Global interfaces/init */
2322 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2323 const char *buffer, size_t size);
2324 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2325 struct kobj_attribute *attr,
2326 const char *buffer, size_t size);
2328 kobj_attribute_write(register, register_bcache);
2329 kobj_attribute_write(register_quiet, register_bcache);
2330 kobj_attribute_write(register_async, register_bcache);
2331 kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
2333 static bool bch_is_open_backing(struct block_device *bdev)
2335 struct cache_set *c, *tc;
2336 struct cached_dev *dc, *t;
2338 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2339 list_for_each_entry_safe(dc, t, &c->cached_devs, list)
2340 if (dc->bdev == bdev)
2342 list_for_each_entry_safe(dc, t, &uncached_devices, list)
2343 if (dc->bdev == bdev)
2348 static bool bch_is_open_cache(struct block_device *bdev)
2350 struct cache_set *c, *tc;
2354 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2355 for_each_cache(ca, c, i)
2356 if (ca->bdev == bdev)
2361 static bool bch_is_open(struct block_device *bdev)
2363 return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
2366 struct async_reg_args {
2367 struct work_struct reg_work;
2369 struct cache_sb *sb;
2370 struct cache_sb_disk *sb_disk;
2371 struct block_device *bdev;
2374 static void register_bdev_worker(struct work_struct *work)
2377 struct async_reg_args *args =
2378 container_of(work, struct async_reg_args, reg_work);
2379 struct cached_dev *dc;
2381 dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2384 put_page(virt_to_page(args->sb_disk));
2385 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2389 mutex_lock(&bch_register_lock);
2390 if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
2392 mutex_unlock(&bch_register_lock);
2396 pr_info("error %s: fail to register backing device\n",
2401 module_put(THIS_MODULE);
2404 static void register_cache_worker(struct work_struct *work)
2407 struct async_reg_args *args =
2408 container_of(work, struct async_reg_args, reg_work);
2411 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2414 put_page(virt_to_page(args->sb_disk));
2415 blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2419 /* blkdev_put() will be called in bch_cache_release() */
2420 if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
2425 pr_info("error %s: fail to register cache device\n",
2430 module_put(THIS_MODULE);
2433 static void register_device_aync(struct async_reg_args *args)
2435 if (SB_IS_BDEV(args->sb))
2436 INIT_WORK(&args->reg_work, register_bdev_worker);
2438 INIT_WORK(&args->reg_work, register_cache_worker);
2440 queue_work(system_wq, &args->reg_work);
2443 static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
2444 const char *buffer, size_t size)
2448 struct cache_sb *sb;
2449 struct cache_sb_disk *sb_disk;
2450 struct block_device *bdev;
2454 err = "failed to reference bcache module";
2455 if (!try_module_get(THIS_MODULE))
2458 /* For latest state of bcache_is_reboot */
2460 err = "bcache is in reboot";
2461 if (bcache_is_reboot)
2462 goto out_module_put;
2465 err = "cannot allocate memory";
2466 path = kstrndup(buffer, size, GFP_KERNEL);
2468 goto out_module_put;
2470 sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
2475 err = "failed to open device";
2476 bdev = blkdev_get_by_path(strim(path),
2477 FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2480 if (bdev == ERR_PTR(-EBUSY)) {
2481 bdev = lookup_bdev(strim(path));
2482 mutex_lock(&bch_register_lock);
2483 if (!IS_ERR(bdev) && bch_is_open(bdev))
2484 err = "device already registered";
2486 err = "device busy";
2487 mutex_unlock(&bch_register_lock);
2490 if (attr == &ksysfs_register_quiet)
2496 err = "failed to set blocksize";
2497 if (set_blocksize(bdev, 4096))
2498 goto out_blkdev_put;
2500 err = read_super(sb, bdev, &sb_disk);
2502 goto out_blkdev_put;
2504 err = "failed to register device";
2505 if (attr == &ksysfs_register_async) {
2506 /* register in asynchronous way */
2507 struct async_reg_args *args =
2508 kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
2512 err = "cannot allocate memory";
2513 goto out_put_sb_page;
2518 args->sb_disk = sb_disk;
2520 register_device_aync(args);
2521 /* No wait and returns to user space */
2525 if (SB_IS_BDEV(sb)) {
2526 struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
2529 goto out_put_sb_page;
2531 mutex_lock(&bch_register_lock);
2532 ret = register_bdev(sb, sb_disk, bdev, dc);
2533 mutex_unlock(&bch_register_lock);
2534 /* blkdev_put() will be called in cached_dev_free() */
2538 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
2541 goto out_put_sb_page;
2543 /* blkdev_put() will be called in bch_cache_release() */
2544 if (register_cache(sb, sb_disk, bdev, ca) != 0)
2551 module_put(THIS_MODULE);
2556 put_page(virt_to_page(sb_disk));
2558 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
2565 module_put(THIS_MODULE);
2567 pr_info("error %s: %s\n", path?path:"", err);
2573 struct list_head list;
2574 struct cached_dev *dc;
2577 static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
2578 struct kobj_attribute *attr,
2582 LIST_HEAD(pending_devs);
2584 struct cached_dev *dc, *tdc;
2585 struct pdev *pdev, *tpdev;
2586 struct cache_set *c, *tc;
2588 mutex_lock(&bch_register_lock);
2589 list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
2590 pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
2594 list_add(&pdev->list, &pending_devs);
2597 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2598 list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
2599 char *pdev_set_uuid = pdev->dc->sb.set_uuid;
2600 char *set_uuid = c->sb.uuid;
2602 if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
2603 list_del(&pdev->list);
2609 mutex_unlock(&bch_register_lock);
2611 list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
2612 pr_info("delete pdev %p\n", pdev);
2613 list_del(&pdev->list);
2614 bcache_device_stop(&pdev->dc->disk);
2621 static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
2623 if (bcache_is_reboot)
2626 if (code == SYS_DOWN ||
2628 code == SYS_POWER_OFF) {
2630 unsigned long start = jiffies;
2631 bool stopped = false;
2633 struct cache_set *c, *tc;
2634 struct cached_dev *dc, *tdc;
2636 mutex_lock(&bch_register_lock);
2638 if (bcache_is_reboot)
2641 /* New registration is rejected since now */
2642 bcache_is_reboot = true;
2644 * Make registering caller (if there is) on other CPU
2645 * core know bcache_is_reboot set to true earlier
2649 if (list_empty(&bch_cache_sets) &&
2650 list_empty(&uncached_devices))
2653 mutex_unlock(&bch_register_lock);
2655 pr_info("Stopping all devices:\n");
2658 * The reason bch_register_lock is not held to call
2659 * bch_cache_set_stop() and bcache_device_stop() is to
2660 * avoid potential deadlock during reboot, because cache
2661 * set or bcache device stopping process will acqurie
2662 * bch_register_lock too.
2664 * We are safe here because bcache_is_reboot sets to
2665 * true already, register_bcache() will reject new
2666 * registration now. bcache_is_reboot also makes sure
2667 * bcache_reboot() won't be re-entered on by other thread,
2668 * so there is no race in following list iteration by
2669 * list_for_each_entry_safe().
2671 list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
2672 bch_cache_set_stop(c);
2674 list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
2675 bcache_device_stop(&dc->disk);
2679 * Give an early chance for other kthreads and
2680 * kworkers to stop themselves
2684 /* What's a condition variable? */
2686 long timeout = start + 10 * HZ - jiffies;
2688 mutex_lock(&bch_register_lock);
2689 stopped = list_empty(&bch_cache_sets) &&
2690 list_empty(&uncached_devices);
2692 if (timeout < 0 || stopped)
2695 prepare_to_wait(&unregister_wait, &wait,
2696 TASK_UNINTERRUPTIBLE);
2698 mutex_unlock(&bch_register_lock);
2699 schedule_timeout(timeout);
2702 finish_wait(&unregister_wait, &wait);
2705 pr_info("All devices stopped\n");
2707 pr_notice("Timeout waiting for devices to be closed\n");
2709 mutex_unlock(&bch_register_lock);
2715 static struct notifier_block reboot = {
2716 .notifier_call = bcache_reboot,
2717 .priority = INT_MAX, /* before any real devices */
2720 static void bcache_exit(void)
2725 kobject_put(bcache_kobj);
2727 destroy_workqueue(bcache_wq);
2729 destroy_workqueue(bch_journal_wq);
2732 unregister_blkdev(bcache_major, "bcache");
2733 unregister_reboot_notifier(&reboot);
2734 mutex_destroy(&bch_register_lock);
2737 /* Check and fixup module parameters */
2738 static void check_module_parameters(void)
2740 if (bch_cutoff_writeback_sync == 0)
2741 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
2742 else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
2743 pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
2744 bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
2745 bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
2748 if (bch_cutoff_writeback == 0)
2749 bch_cutoff_writeback = CUTOFF_WRITEBACK;
2750 else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
2751 pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
2752 bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
2753 bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
2756 if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
2757 pr_warn("set bch_cutoff_writeback (%u) to %u\n",
2758 bch_cutoff_writeback, bch_cutoff_writeback_sync);
2759 bch_cutoff_writeback = bch_cutoff_writeback_sync;
2763 static int __init bcache_init(void)
2765 static const struct attribute *files[] = {
2766 &ksysfs_register.attr,
2767 &ksysfs_register_quiet.attr,
2768 #ifdef CONFIG_BCACHE_ASYNC_REGISTRAION
2769 &ksysfs_register_async.attr,
2771 &ksysfs_pendings_cleanup.attr,
2775 check_module_parameters();
2777 mutex_init(&bch_register_lock);
2778 init_waitqueue_head(&unregister_wait);
2779 register_reboot_notifier(&reboot);
2781 bcache_major = register_blkdev(0, "bcache");
2782 if (bcache_major < 0) {
2783 unregister_reboot_notifier(&reboot);
2784 mutex_destroy(&bch_register_lock);
2785 return bcache_major;
2788 bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
2792 bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
2793 if (!bch_journal_wq)
2796 bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
2800 if (bch_request_init() ||
2801 sysfs_create_files(bcache_kobj, files))
2805 closure_debug_init();
2807 bcache_is_reboot = false;
2818 module_exit(bcache_exit);
2819 module_init(bcache_init);
2821 module_param(bch_cutoff_writeback, uint, 0);
2822 MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
2824 module_param(bch_cutoff_writeback_sync, uint, 0);
2825 MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
2827 MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
2828 MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
2829 MODULE_LICENSE("GPL");