https://github.com/torvalds/linux
Tip revision: 6e4664525b1db28f8c4e1130957f70a94c19213e authored by Linus Torvalds on 02 September 2013, 20:46:10 UTC
Linux 3.11
Linux 3.11
Tip revision: 6e46645
super.c
/*
* bcache setup/teardown code, and some metadata io - read a superblock and
* figure out what to do with it.
*
* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
* Copyright 2012 Google, Inc.
*/
#include "bcache.h"
#include "btree.h"
#include "debug.h"
#include "request.h"
#include "writeback.h"
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/debugfs.h>
#include <linux/genhd.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/reboot.h>
#include <linux/sysfs.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
static const char bcache_magic[] = {
0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
};
static const char invalid_uuid[] = {
0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
};
/* Default is -1; we skip past it for struct cached_dev's cache mode */
const char * const bch_cache_modes[] = {
"default",
"writethrough",
"writeback",
"writearound",
"none",
NULL
};
struct uuid_entry_v0 {
uint8_t uuid[16];
uint8_t label[32];
uint32_t first_reg;
uint32_t last_reg;
uint32_t invalidated;
uint32_t pad;
};
static struct kobject *bcache_kobj;
struct mutex bch_register_lock;
LIST_HEAD(bch_cache_sets);
static LIST_HEAD(uncached_devices);
static int bcache_major, bcache_minor;
static wait_queue_head_t unregister_wait;
struct workqueue_struct *bcache_wq;
#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
static void bio_split_pool_free(struct bio_split_pool *p)
{
if (p->bio_split_hook)
mempool_destroy(p->bio_split_hook);
if (p->bio_split)
bioset_free(p->bio_split);
}
static int bio_split_pool_init(struct bio_split_pool *p)
{
p->bio_split = bioset_create(4, 0);
if (!p->bio_split)
return -ENOMEM;
p->bio_split_hook = mempool_create_kmalloc_pool(4,
sizeof(struct bio_split_hook));
if (!p->bio_split_hook)
return -ENOMEM;
return 0;
}
/* Superblock */
static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
struct page **res)
{
const char *err;
struct cache_sb *s;
struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
unsigned i;
if (!bh)
return "IO error";
s = (struct cache_sb *) bh->b_data;
sb->offset = le64_to_cpu(s->offset);
sb->version = le64_to_cpu(s->version);
memcpy(sb->magic, s->magic, 16);
memcpy(sb->uuid, s->uuid, 16);
memcpy(sb->set_uuid, s->set_uuid, 16);
memcpy(sb->label, s->label, SB_LABEL_SIZE);
sb->flags = le64_to_cpu(s->flags);
sb->seq = le64_to_cpu(s->seq);
sb->last_mount = le32_to_cpu(s->last_mount);
sb->first_bucket = le16_to_cpu(s->first_bucket);
sb->keys = le16_to_cpu(s->keys);
for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
sb->d[i] = le64_to_cpu(s->d[i]);
pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
sb->version, sb->flags, sb->seq, sb->keys);
err = "Not a bcache superblock";
if (sb->offset != SB_SECTOR)
goto err;
if (memcmp(sb->magic, bcache_magic, 16))
goto err;
err = "Too many journal buckets";
if (sb->keys > SB_JOURNAL_BUCKETS)
goto err;
err = "Bad checksum";
if (s->csum != csum_set(s))
goto err;
err = "Bad UUID";
if (bch_is_zero(sb->uuid, 16))
goto err;
sb->block_size = le16_to_cpu(s->block_size);
err = "Superblock block size smaller than device block size";
if (sb->block_size << 9 < bdev_logical_block_size(bdev))
goto err;
switch (sb->version) {
case BCACHE_SB_VERSION_BDEV:
sb->data_offset = BDEV_DATA_START_DEFAULT;
break;
case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
sb->data_offset = le64_to_cpu(s->data_offset);
err = "Bad data offset";
if (sb->data_offset < BDEV_DATA_START_DEFAULT)
goto err;
break;
case BCACHE_SB_VERSION_CDEV:
case BCACHE_SB_VERSION_CDEV_WITH_UUID:
sb->nbuckets = le64_to_cpu(s->nbuckets);
sb->block_size = le16_to_cpu(s->block_size);
sb->bucket_size = le16_to_cpu(s->bucket_size);
sb->nr_in_set = le16_to_cpu(s->nr_in_set);
sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
err = "Too many buckets";
if (sb->nbuckets > LONG_MAX)
goto err;
err = "Not enough buckets";
if (sb->nbuckets < 1 << 7)
goto err;
err = "Bad block/bucket size";
if (!is_power_of_2(sb->block_size) ||
sb->block_size > PAGE_SECTORS ||
!is_power_of_2(sb->bucket_size) ||
sb->bucket_size < PAGE_SECTORS)
goto err;
err = "Invalid superblock: device too small";
if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets)
goto err;
err = "Bad UUID";
if (bch_is_zero(sb->set_uuid, 16))
goto err;
err = "Bad cache device number in set";
if (!sb->nr_in_set ||
sb->nr_in_set <= sb->nr_this_dev ||
sb->nr_in_set > MAX_CACHES_PER_SET)
goto err;
err = "Journal buckets not sequential";
for (i = 0; i < sb->keys; i++)
if (sb->d[i] != sb->first_bucket + i)
goto err;
err = "Too many journal buckets";
if (sb->first_bucket + sb->keys > sb->nbuckets)
goto err;
err = "Invalid superblock: first bucket comes before end of super";
if (sb->first_bucket * sb->bucket_size < 16)
goto err;
break;
default:
err = "Unsupported superblock version";
goto err;
}
sb->last_mount = get_seconds();
err = NULL;
get_page(bh->b_page);
*res = bh->b_page;
err:
put_bh(bh);
return err;
}
static void write_bdev_super_endio(struct bio *bio, int error)
{
struct cached_dev *dc = bio->bi_private;
/* XXX: error checking */
closure_put(&dc->sb_write.cl);
}
static void __write_super(struct cache_sb *sb, struct bio *bio)
{
struct cache_sb *out = page_address(bio->bi_io_vec[0].bv_page);
unsigned i;
bio->bi_sector = SB_SECTOR;
bio->bi_rw = REQ_SYNC|REQ_META;
bio->bi_size = SB_SIZE;
bch_bio_map(bio, NULL);
out->offset = cpu_to_le64(sb->offset);
out->version = cpu_to_le64(sb->version);
memcpy(out->uuid, sb->uuid, 16);
memcpy(out->set_uuid, sb->set_uuid, 16);
memcpy(out->label, sb->label, SB_LABEL_SIZE);
out->flags = cpu_to_le64(sb->flags);
out->seq = cpu_to_le64(sb->seq);
out->last_mount = cpu_to_le32(sb->last_mount);
out->first_bucket = cpu_to_le16(sb->first_bucket);
out->keys = cpu_to_le16(sb->keys);
for (i = 0; i < sb->keys; i++)
out->d[i] = cpu_to_le64(sb->d[i]);
out->csum = csum_set(out);
pr_debug("ver %llu, flags %llu, seq %llu",
sb->version, sb->flags, sb->seq);
submit_bio(REQ_WRITE, bio);
}
void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
{
struct closure *cl = &dc->sb_write.cl;
struct bio *bio = &dc->sb_bio;
closure_lock(&dc->sb_write, parent);
bio_reset(bio);
bio->bi_bdev = dc->bdev;
bio->bi_end_io = write_bdev_super_endio;
bio->bi_private = dc;
closure_get(cl);
__write_super(&dc->sb, bio);
closure_return(cl);
}
static void write_super_endio(struct bio *bio, int error)
{
struct cache *ca = bio->bi_private;
bch_count_io_errors(ca, error, "writing superblock");
closure_put(&ca->set->sb_write.cl);
}
void bcache_write_super(struct cache_set *c)
{
struct closure *cl = &c->sb_write.cl;
struct cache *ca;
unsigned i;
closure_lock(&c->sb_write, &c->cl);
c->sb.seq++;
for_each_cache(ca, c, i) {
struct bio *bio = &ca->sb_bio;
ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
ca->sb.seq = c->sb.seq;
ca->sb.last_mount = c->sb.last_mount;
SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
bio_reset(bio);
bio->bi_bdev = ca->bdev;
bio->bi_end_io = write_super_endio;
bio->bi_private = ca;
closure_get(cl);
__write_super(&ca->sb, bio);
}
closure_return(cl);
}
/* UUID io */
static void uuid_endio(struct bio *bio, int error)
{
struct closure *cl = bio->bi_private;
struct cache_set *c = container_of(cl, struct cache_set, uuid_write.cl);
cache_set_err_on(error, c, "accessing uuids");
bch_bbio_free(bio, c);
closure_put(cl);
}
static void uuid_io(struct cache_set *c, unsigned long rw,
struct bkey *k, struct closure *parent)
{
struct closure *cl = &c->uuid_write.cl;
struct uuid_entry *u;
unsigned i;
char buf[80];
BUG_ON(!parent);
closure_lock(&c->uuid_write, parent);
for (i = 0; i < KEY_PTRS(k); i++) {
struct bio *bio = bch_bbio_alloc(c);
bio->bi_rw = REQ_SYNC|REQ_META|rw;
bio->bi_size = KEY_SIZE(k) << 9;
bio->bi_end_io = uuid_endio;
bio->bi_private = cl;
bch_bio_map(bio, c->uuids);
bch_submit_bbio(bio, c, k, i);
if (!(rw & WRITE))
break;
}
bch_bkey_to_text(buf, sizeof(buf), k);
pr_debug("%s UUIDs at %s", rw & REQ_WRITE ? "wrote" : "read", buf);
for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
if (!bch_is_zero(u->uuid, 16))
pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
u - c->uuids, u->uuid, u->label,
u->first_reg, u->last_reg, u->invalidated);
closure_return(cl);
}
static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
{
struct bkey *k = &j->uuid_bucket;
if (__bch_ptr_invalid(c, 1, k))
return "bad uuid pointer";
bkey_copy(&c->uuid_bucket, k);
uuid_io(c, READ_SYNC, k, cl);
if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
struct uuid_entry_v0 *u0 = (void *) c->uuids;
struct uuid_entry *u1 = (void *) c->uuids;
int i;
closure_sync(cl);
/*
* Since the new uuid entry is bigger than the old, we have to
* convert starting at the highest memory address and work down
* in order to do it in place
*/
for (i = c->nr_uuids - 1;
i >= 0;
--i) {
memcpy(u1[i].uuid, u0[i].uuid, 16);
memcpy(u1[i].label, u0[i].label, 32);
u1[i].first_reg = u0[i].first_reg;
u1[i].last_reg = u0[i].last_reg;
u1[i].invalidated = u0[i].invalidated;
u1[i].flags = 0;
u1[i].sectors = 0;
}
}
return NULL;
}
static int __uuid_write(struct cache_set *c)
{
BKEY_PADDED(key) k;
struct closure cl;
closure_init_stack(&cl);
lockdep_assert_held(&bch_register_lock);
if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, &cl))
return 1;
SET_KEY_SIZE(&k.key, c->sb.bucket_size);
uuid_io(c, REQ_WRITE, &k.key, &cl);
closure_sync(&cl);
bkey_copy(&c->uuid_bucket, &k.key);
__bkey_put(c, &k.key);
return 0;
}
int bch_uuid_write(struct cache_set *c)
{
int ret = __uuid_write(c);
if (!ret)
bch_journal_meta(c, NULL);
return ret;
}
static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
{
struct uuid_entry *u;
for (u = c->uuids;
u < c->uuids + c->nr_uuids; u++)
if (!memcmp(u->uuid, uuid, 16))
return u;
return NULL;
}
static struct uuid_entry *uuid_find_empty(struct cache_set *c)
{
static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
return uuid_find(c, zero_uuid);
}
/*
* Bucket priorities/gens:
*
* For each bucket, we store on disk its
* 8 bit gen
* 16 bit priority
*
* See alloc.c for an explanation of the gen. The priority is used to implement
* lru (and in the future other) cache replacement policies; for most purposes
* it's just an opaque integer.
*
* The gens and the priorities don't have a whole lot to do with each other, and
* it's actually the gens that must be written out at specific times - it's no
* big deal if the priorities don't get written, if we lose them we just reuse
* buckets in suboptimal order.
*
* On disk they're stored in a packed array, and in as many buckets are required
* to fit them all. The buckets we use to store them form a list; the journal
* header points to the first bucket, the first bucket points to the second
* bucket, et cetera.
*
* This code is used by the allocation code; periodically (whenever it runs out
* of buckets to allocate from) the allocation code will invalidate some
* buckets, but it can't use those buckets until their new gens are safely on
* disk.
*/
static void prio_endio(struct bio *bio, int error)
{
struct cache *ca = bio->bi_private;
cache_set_err_on(error, ca->set, "accessing priorities");
bch_bbio_free(bio, ca->set);
closure_put(&ca->prio);
}
static void prio_io(struct cache *ca, uint64_t bucket, unsigned long rw)
{
struct closure *cl = &ca->prio;
struct bio *bio = bch_bbio_alloc(ca->set);
closure_init_stack(cl);
bio->bi_sector = bucket * ca->sb.bucket_size;
bio->bi_bdev = ca->bdev;
bio->bi_rw = REQ_SYNC|REQ_META|rw;
bio->bi_size = bucket_bytes(ca);
bio->bi_end_io = prio_endio;
bio->bi_private = ca;
bch_bio_map(bio, ca->disk_buckets);
closure_bio_submit(bio, &ca->prio, ca);
closure_sync(cl);
}
#define buckets_free(c) "free %zu, free_inc %zu, unused %zu", \
fifo_used(&c->free), fifo_used(&c->free_inc), fifo_used(&c->unused)
void bch_prio_write(struct cache *ca)
{
int i;
struct bucket *b;
struct closure cl;
closure_init_stack(&cl);
lockdep_assert_held(&ca->set->bucket_lock);
for (b = ca->buckets;
b < ca->buckets + ca->sb.nbuckets; b++)
b->disk_gen = b->gen;
ca->disk_buckets->seq++;
atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
&ca->meta_sectors_written);
pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free),
fifo_used(&ca->free_inc), fifo_used(&ca->unused));
for (i = prio_buckets(ca) - 1; i >= 0; --i) {
long bucket;
struct prio_set *p = ca->disk_buckets;
struct bucket_disk *d = p->data;
struct bucket_disk *end = d + prios_per_bucket(ca);
for (b = ca->buckets + i * prios_per_bucket(ca);
b < ca->buckets + ca->sb.nbuckets && d < end;
b++, d++) {
d->prio = cpu_to_le16(b->prio);
d->gen = b->gen;
}
p->next_bucket = ca->prio_buckets[i + 1];
p->magic = pset_magic(ca);
p->csum = bch_crc64(&p->magic, bucket_bytes(ca) - 8);
bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, &cl);
BUG_ON(bucket == -1);
mutex_unlock(&ca->set->bucket_lock);
prio_io(ca, bucket, REQ_WRITE);
mutex_lock(&ca->set->bucket_lock);
ca->prio_buckets[i] = bucket;
atomic_dec_bug(&ca->buckets[bucket].pin);
}
mutex_unlock(&ca->set->bucket_lock);
bch_journal_meta(ca->set, &cl);
closure_sync(&cl);
mutex_lock(&ca->set->bucket_lock);
ca->need_save_prio = 0;
/*
* Don't want the old priorities to get garbage collected until after we
* finish writing the new ones, and they're journalled
*/
for (i = 0; i < prio_buckets(ca); i++)
ca->prio_last_buckets[i] = ca->prio_buckets[i];
}
static void prio_read(struct cache *ca, uint64_t bucket)
{
struct prio_set *p = ca->disk_buckets;
struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
struct bucket *b;
unsigned bucket_nr = 0;
for (b = ca->buckets;
b < ca->buckets + ca->sb.nbuckets;
b++, d++) {
if (d == end) {
ca->prio_buckets[bucket_nr] = bucket;
ca->prio_last_buckets[bucket_nr] = bucket;
bucket_nr++;
prio_io(ca, bucket, READ_SYNC);
if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8))
pr_warn("bad csum reading priorities");
if (p->magic != pset_magic(ca))
pr_warn("bad magic reading priorities");
bucket = p->next_bucket;
d = p->data;
}
b->prio = le16_to_cpu(d->prio);
b->gen = b->disk_gen = b->last_gc = b->gc_gen = d->gen;
}
}
/* Bcache device */
static int open_dev(struct block_device *b, fmode_t mode)
{
struct bcache_device *d = b->bd_disk->private_data;
if (atomic_read(&d->closing))
return -ENXIO;
closure_get(&d->cl);
return 0;
}
static void release_dev(struct gendisk *b, fmode_t mode)
{
struct bcache_device *d = b->private_data;
closure_put(&d->cl);
}
static int ioctl_dev(struct block_device *b, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct bcache_device *d = b->bd_disk->private_data;
return d->ioctl(d, mode, cmd, arg);
}
static const struct block_device_operations bcache_ops = {
.open = open_dev,
.release = release_dev,
.ioctl = ioctl_dev,
.owner = THIS_MODULE,
};
void bcache_device_stop(struct bcache_device *d)
{
if (!atomic_xchg(&d->closing, 1))
closure_queue(&d->cl);
}
static void bcache_device_unlink(struct bcache_device *d)
{
unsigned i;
struct cache *ca;
sysfs_remove_link(&d->c->kobj, d->name);
sysfs_remove_link(&d->kobj, "cache");
for_each_cache(ca, d->c, i)
bd_unlink_disk_holder(ca->bdev, d->disk);
}
static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
const char *name)
{
unsigned i;
struct cache *ca;
for_each_cache(ca, d->c, i)
bd_link_disk_holder(ca->bdev, d->disk);
snprintf(d->name, BCACHEDEVNAME_SIZE,
"%s%u", name, d->id);
WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
sysfs_create_link(&c->kobj, &d->kobj, d->name),
"Couldn't create device <-> cache set symlinks");
}
static void bcache_device_detach(struct bcache_device *d)
{
lockdep_assert_held(&bch_register_lock);
if (atomic_read(&d->detaching)) {
struct uuid_entry *u = d->c->uuids + d->id;
SET_UUID_FLASH_ONLY(u, 0);
memcpy(u->uuid, invalid_uuid, 16);
u->invalidated = cpu_to_le32(get_seconds());
bch_uuid_write(d->c);
atomic_set(&d->detaching, 0);
}
if (!d->flush_done)
bcache_device_unlink(d);
d->c->devices[d->id] = NULL;
closure_put(&d->c->caching);
d->c = NULL;
}
static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
unsigned id)
{
BUG_ON(test_bit(CACHE_SET_STOPPING, &c->flags));
d->id = id;
d->c = c;
c->devices[id] = d;
closure_get(&c->caching);
}
static void bcache_device_free(struct bcache_device *d)
{
lockdep_assert_held(&bch_register_lock);
pr_info("%s stopped", d->disk->disk_name);
if (d->c)
bcache_device_detach(d);
if (d->disk && d->disk->flags & GENHD_FL_UP)
del_gendisk(d->disk);
if (d->disk && d->disk->queue)
blk_cleanup_queue(d->disk->queue);
if (d->disk)
put_disk(d->disk);
bio_split_pool_free(&d->bio_split_hook);
if (d->unaligned_bvec)
mempool_destroy(d->unaligned_bvec);
if (d->bio_split)
bioset_free(d->bio_split);
if (is_vmalloc_addr(d->stripe_sectors_dirty))
vfree(d->stripe_sectors_dirty);
else
kfree(d->stripe_sectors_dirty);
closure_debug_destroy(&d->cl);
}
static int bcache_device_init(struct bcache_device *d, unsigned block_size,
sector_t sectors)
{
struct request_queue *q;
size_t n;
if (!d->stripe_size_bits)
d->stripe_size_bits = 31;
d->nr_stripes = round_up(sectors, 1 << d->stripe_size_bits) >>
d->stripe_size_bits;
if (!d->nr_stripes || d->nr_stripes > SIZE_MAX / sizeof(atomic_t))
return -ENOMEM;
n = d->nr_stripes * sizeof(atomic_t);
d->stripe_sectors_dirty = n < PAGE_SIZE << 6
? kzalloc(n, GFP_KERNEL)
: vzalloc(n);
if (!d->stripe_sectors_dirty)
return -ENOMEM;
if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
!(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
bio_split_pool_init(&d->bio_split_hook) ||
!(d->disk = alloc_disk(1)) ||
!(q = blk_alloc_queue(GFP_KERNEL)))
return -ENOMEM;
set_capacity(d->disk, sectors);
snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor);
d->disk->major = bcache_major;
d->disk->first_minor = bcache_minor++;
d->disk->fops = &bcache_ops;
d->disk->private_data = d;
blk_queue_make_request(q, NULL);
d->disk->queue = q;
q->queuedata = d;
q->backing_dev_info.congested_data = d;
q->limits.max_hw_sectors = UINT_MAX;
q->limits.max_sectors = UINT_MAX;
q->limits.max_segment_size = UINT_MAX;
q->limits.max_segments = BIO_MAX_PAGES;
q->limits.max_discard_sectors = UINT_MAX;
q->limits.io_min = block_size;
q->limits.logical_block_size = block_size;
q->limits.physical_block_size = block_size;
set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags);
set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags);
blk_queue_flush(q, REQ_FLUSH|REQ_FUA);
return 0;
}
/* Cached device */
static void calc_cached_dev_sectors(struct cache_set *c)
{
uint64_t sectors = 0;
struct cached_dev *dc;
list_for_each_entry(dc, &c->cached_devs, list)
sectors += bdev_sectors(dc->bdev);
c->cached_dev_sectors = sectors;
}
void bch_cached_dev_run(struct cached_dev *dc)
{
struct bcache_device *d = &dc->disk;
char buf[SB_LABEL_SIZE + 1];
char *env[] = {
"DRIVER=bcache",
kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
NULL,
NULL,
};
memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
buf[SB_LABEL_SIZE] = '\0';
env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf);
if (atomic_xchg(&dc->running, 1))
return;
if (!d->c &&
BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
struct closure cl;
closure_init_stack(&cl);
SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
bch_write_bdev_super(dc, &cl);
closure_sync(&cl);
}
add_disk(d->disk);
bd_link_disk_holder(dc->bdev, dc->disk.disk);
/* won't show up in the uevent file, use udevadm monitor -e instead
* only class / kset properties are persistent */
kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
kfree(env[1]);
kfree(env[2]);
if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
pr_debug("error creating sysfs link");
}
static void cached_dev_detach_finish(struct work_struct *w)
{
struct cached_dev *dc = container_of(w, struct cached_dev, detach);
char buf[BDEVNAME_SIZE];
struct closure cl;
closure_init_stack(&cl);
BUG_ON(!atomic_read(&dc->disk.detaching));
BUG_ON(atomic_read(&dc->count));
mutex_lock(&bch_register_lock);
memset(&dc->sb.set_uuid, 0, 16);
SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
bch_write_bdev_super(dc, &cl);
closure_sync(&cl);
bcache_device_detach(&dc->disk);
list_move(&dc->list, &uncached_devices);
mutex_unlock(&bch_register_lock);
pr_info("Caching disabled for %s", bdevname(dc->bdev, buf));
/* Drop ref we took in cached_dev_detach() */
closure_put(&dc->disk.cl);
}
void bch_cached_dev_detach(struct cached_dev *dc)
{
lockdep_assert_held(&bch_register_lock);
if (atomic_read(&dc->disk.closing))
return;
if (atomic_xchg(&dc->disk.detaching, 1))
return;
/*
* Block the device from being closed and freed until we're finished
* detaching
*/
closure_get(&dc->disk.cl);
bch_writeback_queue(dc);
cached_dev_put(dc);
}
int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c)
{
uint32_t rtime = cpu_to_le32(get_seconds());
struct uuid_entry *u;
char buf[BDEVNAME_SIZE];
bdevname(dc->bdev, buf);
if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))
return -ENOENT;
if (dc->disk.c) {
pr_err("Can't attach %s: already attached", buf);
return -EINVAL;
}
if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
pr_err("Can't attach %s: shutting down", buf);
return -EINVAL;
}
if (dc->sb.block_size < c->sb.block_size) {
/* Will die */
pr_err("Couldn't attach %s: block size less than set's block size",
buf);
return -EINVAL;
}
u = uuid_find(c, dc->sb.uuid);
if (u &&
(BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
memcpy(u->uuid, invalid_uuid, 16);
u->invalidated = cpu_to_le32(get_seconds());
u = NULL;
}
if (!u) {
if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
pr_err("Couldn't find uuid for %s in set", buf);
return -ENOENT;
}
u = uuid_find_empty(c);
if (!u) {
pr_err("Not caching %s, no room for UUID", buf);
return -EINVAL;
}
}
/* Deadlocks since we're called via sysfs...
sysfs_remove_file(&dc->kobj, &sysfs_attach);
*/
if (bch_is_zero(u->uuid, 16)) {
struct closure cl;
closure_init_stack(&cl);
memcpy(u->uuid, dc->sb.uuid, 16);
memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
u->first_reg = u->last_reg = rtime;
bch_uuid_write(c);
memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
bch_write_bdev_super(dc, &cl);
closure_sync(&cl);
} else {
u->last_reg = rtime;
bch_uuid_write(c);
}
bcache_device_attach(&dc->disk, c, u - c->uuids);
list_move(&dc->list, &c->cached_devs);
calc_cached_dev_sectors(c);
smp_wmb();
/*
* dc->c must be set before dc->count != 0 - paired with the mb in
* cached_dev_get()
*/
atomic_set(&dc->count, 1);
if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
bch_sectors_dirty_init(dc);
atomic_set(&dc->has_dirty, 1);
atomic_inc(&dc->count);
bch_writeback_queue(dc);
}
bch_cached_dev_run(dc);
bcache_device_link(&dc->disk, c, "bdev");
pr_info("Caching %s as %s on set %pU",
bdevname(dc->bdev, buf), dc->disk.disk->disk_name,
dc->disk.c->sb.set_uuid);
return 0;
}
void bch_cached_dev_release(struct kobject *kobj)
{
struct cached_dev *dc = container_of(kobj, struct cached_dev,
disk.kobj);
kfree(dc);
module_put(THIS_MODULE);
}
static void cached_dev_free(struct closure *cl)
{
struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
cancel_delayed_work_sync(&dc->writeback_rate_update);
mutex_lock(&bch_register_lock);
if (atomic_read(&dc->running))
bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
bcache_device_free(&dc->disk);
list_del(&dc->list);
mutex_unlock(&bch_register_lock);
if (!IS_ERR_OR_NULL(dc->bdev)) {
if (dc->bdev->bd_disk)
blk_sync_queue(bdev_get_queue(dc->bdev));
blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
}
wake_up(&unregister_wait);
kobject_put(&dc->disk.kobj);
}
static void cached_dev_flush(struct closure *cl)
{
struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
struct bcache_device *d = &dc->disk;
mutex_lock(&bch_register_lock);
d->flush_done = 1;
if (d->c)
bcache_device_unlink(d);
mutex_unlock(&bch_register_lock);
bch_cache_accounting_destroy(&dc->accounting);
kobject_del(&d->kobj);
continue_at(cl, cached_dev_free, system_wq);
}
static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
{
int ret;
struct io *io;
struct request_queue *q = bdev_get_queue(dc->bdev);
__module_get(THIS_MODULE);
INIT_LIST_HEAD(&dc->list);
closure_init(&dc->disk.cl, NULL);
set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
INIT_WORK(&dc->detach, cached_dev_detach_finish);
closure_init_unlocked(&dc->sb_write);
INIT_LIST_HEAD(&dc->io_lru);
spin_lock_init(&dc->io_lock);
bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
dc->sequential_merge = true;
dc->sequential_cutoff = 4 << 20;
for (io = dc->io; io < dc->io + RECENT_IO; io++) {
list_add(&io->lru, &dc->io_lru);
hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
}
ret = bcache_device_init(&dc->disk, block_size,
dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
if (ret)
return ret;
set_capacity(dc->disk.disk,
dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
dc->disk.disk->queue->backing_dev_info.ra_pages =
max(dc->disk.disk->queue->backing_dev_info.ra_pages,
q->backing_dev_info.ra_pages);
bch_cached_dev_request_init(dc);
bch_cached_dev_writeback_init(dc);
return 0;
}
/* Cached device - bcache superblock */
static void register_bdev(struct cache_sb *sb, struct page *sb_page,
struct block_device *bdev,
struct cached_dev *dc)
{
char name[BDEVNAME_SIZE];
const char *err = "cannot allocate memory";
struct cache_set *c;
memcpy(&dc->sb, sb, sizeof(struct cache_sb));
dc->bdev = bdev;
dc->bdev->bd_holder = dc;
bio_init(&dc->sb_bio);
dc->sb_bio.bi_max_vecs = 1;
dc->sb_bio.bi_io_vec = dc->sb_bio.bi_inline_vecs;
dc->sb_bio.bi_io_vec[0].bv_page = sb_page;
get_page(sb_page);
if (cached_dev_init(dc, sb->block_size << 9))
goto err;
err = "error creating kobject";
if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
"bcache"))
goto err;
if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
goto err;
pr_info("registered backing device %s", bdevname(bdev, name));
list_add(&dc->list, &uncached_devices);
list_for_each_entry(c, &bch_cache_sets, list)
bch_cached_dev_attach(dc, c);
if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
bch_cached_dev_run(dc);
return;
err:
pr_notice("error opening %s: %s", bdevname(bdev, name), err);
bcache_device_stop(&dc->disk);
}
/* Flash only volumes */
void bch_flash_dev_release(struct kobject *kobj)
{
struct bcache_device *d = container_of(kobj, struct bcache_device,
kobj);
kfree(d);
}
static void flash_dev_free(struct closure *cl)
{
struct bcache_device *d = container_of(cl, struct bcache_device, cl);
bcache_device_free(d);
kobject_put(&d->kobj);
}
static void flash_dev_flush(struct closure *cl)
{
struct bcache_device *d = container_of(cl, struct bcache_device, cl);
bcache_device_unlink(d);
kobject_del(&d->kobj);
continue_at(cl, flash_dev_free, system_wq);
}
static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
{
struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
GFP_KERNEL);
if (!d)
return -ENOMEM;
closure_init(&d->cl, NULL);
set_closure_fn(&d->cl, flash_dev_flush, system_wq);
kobject_init(&d->kobj, &bch_flash_dev_ktype);
if (bcache_device_init(d, block_bytes(c), u->sectors))
goto err;
bcache_device_attach(d, c, u - c->uuids);
bch_flash_dev_request_init(d);
add_disk(d->disk);
if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
goto err;
bcache_device_link(d, c, "volume");
return 0;
err:
kobject_put(&d->kobj);
return -ENOMEM;
}
static int flash_devs_run(struct cache_set *c)
{
int ret = 0;
struct uuid_entry *u;
for (u = c->uuids;
u < c->uuids + c->nr_uuids && !ret;
u++)
if (UUID_FLASH_ONLY(u))
ret = flash_dev_run(c, u);
return ret;
}
int bch_flash_dev_create(struct cache_set *c, uint64_t size)
{
struct uuid_entry *u;
if (test_bit(CACHE_SET_STOPPING, &c->flags))
return -EINTR;
u = uuid_find_empty(c);
if (!u) {
pr_err("Can't create volume, no room for UUID");
return -EINVAL;
}
get_random_bytes(u->uuid, 16);
memset(u->label, 0, 32);
u->first_reg = u->last_reg = cpu_to_le32(get_seconds());
SET_UUID_FLASH_ONLY(u, 1);
u->sectors = size >> 9;
bch_uuid_write(c);
return flash_dev_run(c, u);
}
/* Cache set */
__printf(2, 3)
bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
{
va_list args;
if (test_bit(CACHE_SET_STOPPING, &c->flags))
return false;
/* XXX: we can be called from atomic context
acquire_console_sem();
*/
printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid);
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
printk(", disabling caching\n");
bch_cache_set_unregister(c);
return true;
}
void bch_cache_set_release(struct kobject *kobj)
{
struct cache_set *c = container_of(kobj, struct cache_set, kobj);
kfree(c);
module_put(THIS_MODULE);
}
static void cache_set_free(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, cl);
struct cache *ca;
unsigned i;
if (!IS_ERR_OR_NULL(c->debug))
debugfs_remove(c->debug);
bch_open_buckets_free(c);
bch_btree_cache_free(c);
bch_journal_free(c);
for_each_cache(ca, c, i)
if (ca)
kobject_put(&ca->kobj);
free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
free_pages((unsigned long) c->sort, ilog2(bucket_pages(c)));
if (c->bio_split)
bioset_free(c->bio_split);
if (c->fill_iter)
mempool_destroy(c->fill_iter);
if (c->bio_meta)
mempool_destroy(c->bio_meta);
if (c->search)
mempool_destroy(c->search);
kfree(c->devices);
mutex_lock(&bch_register_lock);
list_del(&c->list);
mutex_unlock(&bch_register_lock);
pr_info("Cache set %pU unregistered", c->sb.set_uuid);
wake_up(&unregister_wait);
closure_debug_destroy(&c->cl);
kobject_put(&c->kobj);
}
static void cache_set_flush(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, caching);
struct cache *ca;
struct btree *b;
unsigned i;
bch_cache_accounting_destroy(&c->accounting);
kobject_put(&c->internal);
kobject_del(&c->kobj);
if (!IS_ERR_OR_NULL(c->root))
list_add(&c->root->list, &c->btree_cache);
/* Should skip this if we're unregistering because of an error */
list_for_each_entry(b, &c->btree_cache, list)
if (btree_node_dirty(b))
bch_btree_node_write(b, NULL);
for_each_cache(ca, c, i)
if (ca->alloc_thread)
kthread_stop(ca->alloc_thread);
closure_return(cl);
}
static void __cache_set_unregister(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, caching);
struct cached_dev *dc;
size_t i;
mutex_lock(&bch_register_lock);
for (i = 0; i < c->nr_uuids; i++)
if (c->devices[i]) {
if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
dc = container_of(c->devices[i],
struct cached_dev, disk);
bch_cached_dev_detach(dc);
} else {
bcache_device_stop(c->devices[i]);
}
}
mutex_unlock(&bch_register_lock);
continue_at(cl, cache_set_flush, system_wq);
}
void bch_cache_set_stop(struct cache_set *c)
{
if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
closure_queue(&c->caching);
}
void bch_cache_set_unregister(struct cache_set *c)
{
set_bit(CACHE_SET_UNREGISTERING, &c->flags);
bch_cache_set_stop(c);
}
#define alloc_bucket_pages(gfp, c) \
((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
{
int iter_size;
struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
if (!c)
return NULL;
__module_get(THIS_MODULE);
closure_init(&c->cl, NULL);
set_closure_fn(&c->cl, cache_set_free, system_wq);
closure_init(&c->caching, &c->cl);
set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
/* Maybe create continue_at_noreturn() and use it here? */
closure_set_stopped(&c->cl);
closure_put(&c->cl);
kobject_init(&c->kobj, &bch_cache_set_ktype);
kobject_init(&c->internal, &bch_cache_set_internal_ktype);
bch_cache_accounting_init(&c->accounting, &c->cl);
memcpy(c->sb.set_uuid, sb->set_uuid, 16);
c->sb.block_size = sb->block_size;
c->sb.bucket_size = sb->bucket_size;
c->sb.nr_in_set = sb->nr_in_set;
c->sb.last_mount = sb->last_mount;
c->bucket_bits = ilog2(sb->bucket_size);
c->block_bits = ilog2(sb->block_size);
c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
c->btree_pages = c->sb.bucket_size / PAGE_SECTORS;
if (c->btree_pages > BTREE_MAX_PAGES)
c->btree_pages = max_t(int, c->btree_pages / 4,
BTREE_MAX_PAGES);
c->sort_crit_factor = int_sqrt(c->btree_pages);
mutex_init(&c->bucket_lock);
mutex_init(&c->sort_lock);
spin_lock_init(&c->sort_time_lock);
closure_init_unlocked(&c->sb_write);
closure_init_unlocked(&c->uuid_write);
spin_lock_init(&c->btree_read_time_lock);
bch_moving_init_cache_set(c);
INIT_LIST_HEAD(&c->list);
INIT_LIST_HEAD(&c->cached_devs);
INIT_LIST_HEAD(&c->btree_cache);
INIT_LIST_HEAD(&c->btree_cache_freeable);
INIT_LIST_HEAD(&c->btree_cache_freed);
INIT_LIST_HEAD(&c->data_buckets);
c->search = mempool_create_slab_pool(32, bch_search_cache);
if (!c->search)
goto err;
iter_size = (sb->bucket_size / sb->block_size + 1) *
sizeof(struct btree_iter_set);
if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) ||
!(c->bio_meta = mempool_create_kmalloc_pool(2,
sizeof(struct bbio) + sizeof(struct bio_vec) *
bucket_pages(c))) ||
!(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) ||
!(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
!(c->sort = alloc_bucket_pages(GFP_KERNEL, c)) ||
!(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
bch_journal_alloc(c) ||
bch_btree_cache_alloc(c) ||
bch_open_buckets_alloc(c))
goto err;
c->congested_read_threshold_us = 2000;
c->congested_write_threshold_us = 20000;
c->error_limit = 8 << IO_ERROR_SHIFT;
return c;
err:
bch_cache_set_unregister(c);
return NULL;
}
static void run_cache_set(struct cache_set *c)
{
const char *err = "cannot allocate memory";
struct cached_dev *dc, *t;
struct cache *ca;
unsigned i;
struct btree_op op;
bch_btree_op_init_stack(&op);
op.lock = SHRT_MAX;
for_each_cache(ca, c, i)
c->nbuckets += ca->sb.nbuckets;
if (CACHE_SYNC(&c->sb)) {
LIST_HEAD(journal);
struct bkey *k;
struct jset *j;
err = "cannot allocate memory for journal";
if (bch_journal_read(c, &journal, &op))
goto err;
pr_debug("btree_journal_read() done");
err = "no journal entries found";
if (list_empty(&journal))
goto err;
j = &list_entry(journal.prev, struct journal_replay, list)->j;
err = "IO error reading priorities";
for_each_cache(ca, c, i)
prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]);
/*
* If prio_read() fails it'll call cache_set_error and we'll
* tear everything down right away, but if we perhaps checked
* sooner we could avoid journal replay.
*/
k = &j->btree_root;
err = "bad btree root";
if (__bch_ptr_invalid(c, j->btree_level + 1, k))
goto err;
err = "error reading btree root";
c->root = bch_btree_node_get(c, k, j->btree_level, &op);
if (IS_ERR_OR_NULL(c->root))
goto err;
list_del_init(&c->root->list);
rw_unlock(true, c->root);
err = uuid_read(c, j, &op.cl);
if (err)
goto err;
err = "error in recovery";
if (bch_btree_check(c, &op))
goto err;
bch_journal_mark(c, &journal);
bch_btree_gc_finish(c);
pr_debug("btree_check() done");
/*
* bcache_journal_next() can't happen sooner, or
* btree_gc_finish() will give spurious errors about last_gc >
* gc_gen - this is a hack but oh well.
*/
bch_journal_next(&c->journal);
err = "error starting allocator thread";
for_each_cache(ca, c, i)
if (bch_cache_allocator_start(ca))
goto err;
/*
* First place it's safe to allocate: btree_check() and
* btree_gc_finish() have to run before we have buckets to
* allocate, and bch_bucket_alloc_set() might cause a journal
* entry to be written so bcache_journal_next() has to be called
* first.
*
* If the uuids were in the old format we have to rewrite them
* before the next journal entry is written:
*/
if (j->version < BCACHE_JSET_VERSION_UUID)
__uuid_write(c);
bch_journal_replay(c, &journal, &op);
} else {
pr_notice("invalidating existing data");
/* Don't want invalidate_buckets() to queue a gc yet */
closure_lock(&c->gc, NULL);
for_each_cache(ca, c, i) {
unsigned j;
ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
2, SB_JOURNAL_BUCKETS);
for (j = 0; j < ca->sb.keys; j++)
ca->sb.d[j] = ca->sb.first_bucket + j;
}
bch_btree_gc_finish(c);
err = "error starting allocator thread";
for_each_cache(ca, c, i)
if (bch_cache_allocator_start(ca))
goto err;
mutex_lock(&c->bucket_lock);
for_each_cache(ca, c, i)
bch_prio_write(ca);
mutex_unlock(&c->bucket_lock);
err = "cannot allocate new UUID bucket";
if (__uuid_write(c))
goto err_unlock_gc;
err = "cannot allocate new btree root";
c->root = bch_btree_node_alloc(c, 0, &op.cl);
if (IS_ERR_OR_NULL(c->root))
goto err_unlock_gc;
bkey_copy_key(&c->root->key, &MAX_KEY);
bch_btree_node_write(c->root, &op.cl);
bch_btree_set_root(c->root);
rw_unlock(true, c->root);
/*
* We don't want to write the first journal entry until
* everything is set up - fortunately journal entries won't be
* written until the SET_CACHE_SYNC() here:
*/
SET_CACHE_SYNC(&c->sb, true);
bch_journal_next(&c->journal);
bch_journal_meta(c, &op.cl);
/* Unlock */
closure_set_stopped(&c->gc.cl);
closure_put(&c->gc.cl);
}
closure_sync(&op.cl);
c->sb.last_mount = get_seconds();
bcache_write_super(c);
list_for_each_entry_safe(dc, t, &uncached_devices, list)
bch_cached_dev_attach(dc, c);
flash_devs_run(c);
return;
err_unlock_gc:
closure_set_stopped(&c->gc.cl);
closure_put(&c->gc.cl);
err:
closure_sync(&op.cl);
/* XXX: test this, it's broken */
bch_cache_set_error(c, err);
}
static bool can_attach_cache(struct cache *ca, struct cache_set *c)
{
return ca->sb.block_size == c->sb.block_size &&
ca->sb.bucket_size == c->sb.block_size &&
ca->sb.nr_in_set == c->sb.nr_in_set;
}
static const char *register_cache_set(struct cache *ca)
{
char buf[12];
const char *err = "cannot allocate memory";
struct cache_set *c;
list_for_each_entry(c, &bch_cache_sets, list)
if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
if (c->cache[ca->sb.nr_this_dev])
return "duplicate cache set member";
if (!can_attach_cache(ca, c))
return "cache sb does not match set";
if (!CACHE_SYNC(&ca->sb))
SET_CACHE_SYNC(&c->sb, false);
goto found;
}
c = bch_cache_set_alloc(&ca->sb);
if (!c)
return err;
err = "error creating kobject";
if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
kobject_add(&c->internal, &c->kobj, "internal"))
goto err;
if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
goto err;
bch_debug_init_cache_set(c);
list_add(&c->list, &bch_cache_sets);
found:
sprintf(buf, "cache%i", ca->sb.nr_this_dev);
if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
sysfs_create_link(&c->kobj, &ca->kobj, buf))
goto err;
if (ca->sb.seq > c->sb.seq) {
c->sb.version = ca->sb.version;
memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
c->sb.flags = ca->sb.flags;
c->sb.seq = ca->sb.seq;
pr_debug("set version = %llu", c->sb.version);
}
ca->set = c;
ca->set->cache[ca->sb.nr_this_dev] = ca;
c->cache_by_alloc[c->caches_loaded++] = ca;
if (c->caches_loaded == c->sb.nr_in_set)
run_cache_set(c);
return NULL;
err:
bch_cache_set_unregister(c);
return err;
}
/* Cache device */
void bch_cache_release(struct kobject *kobj)
{
struct cache *ca = container_of(kobj, struct cache, kobj);
if (ca->set)
ca->set->cache[ca->sb.nr_this_dev] = NULL;
bch_cache_allocator_exit(ca);
bio_split_pool_free(&ca->bio_split_hook);
free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
kfree(ca->prio_buckets);
vfree(ca->buckets);
free_heap(&ca->heap);
free_fifo(&ca->unused);
free_fifo(&ca->free_inc);
free_fifo(&ca->free);
if (ca->sb_bio.bi_inline_vecs[0].bv_page)
put_page(ca->sb_bio.bi_io_vec[0].bv_page);
if (!IS_ERR_OR_NULL(ca->bdev)) {
blk_sync_queue(bdev_get_queue(ca->bdev));
blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
}
kfree(ca);
module_put(THIS_MODULE);
}
static int cache_alloc(struct cache_sb *sb, struct cache *ca)
{
size_t free;
struct bucket *b;
__module_get(THIS_MODULE);
kobject_init(&ca->kobj, &bch_cache_ktype);
INIT_LIST_HEAD(&ca->discards);
bio_init(&ca->journal.bio);
ca->journal.bio.bi_max_vecs = 8;
ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs;
free = roundup_pow_of_two(ca->sb.nbuckets) >> 9;
free = max_t(size_t, free, (prio_buckets(ca) + 8) * 2);
if (!init_fifo(&ca->free, free, GFP_KERNEL) ||
!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) ||
!init_fifo(&ca->unused, free << 2, GFP_KERNEL) ||
!init_heap(&ca->heap, free << 3, GFP_KERNEL) ||
!(ca->buckets = vzalloc(sizeof(struct bucket) *
ca->sb.nbuckets)) ||
!(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) *
2, GFP_KERNEL)) ||
!(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)) ||
bio_split_pool_init(&ca->bio_split_hook))
return -ENOMEM;
ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
for_each_bucket(b, ca)
atomic_set(&b->pin, 0);
if (bch_cache_allocator_init(ca))
goto err;
return 0;
err:
kobject_put(&ca->kobj);
return -ENOMEM;
}
static void register_cache(struct cache_sb *sb, struct page *sb_page,
struct block_device *bdev, struct cache *ca)
{
char name[BDEVNAME_SIZE];
const char *err = "cannot allocate memory";
memcpy(&ca->sb, sb, sizeof(struct cache_sb));
ca->bdev = bdev;
ca->bdev->bd_holder = ca;
bio_init(&ca->sb_bio);
ca->sb_bio.bi_max_vecs = 1;
ca->sb_bio.bi_io_vec = ca->sb_bio.bi_inline_vecs;
ca->sb_bio.bi_io_vec[0].bv_page = sb_page;
get_page(sb_page);
if (blk_queue_discard(bdev_get_queue(ca->bdev)))
ca->discard = CACHE_DISCARD(&ca->sb);
if (cache_alloc(sb, ca) != 0)
goto err;
err = "error creating kobject";
if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache"))
goto err;
err = register_cache_set(ca);
if (err)
goto err;
pr_info("registered cache device %s", bdevname(bdev, name));
return;
err:
pr_notice("error opening %s: %s", bdevname(bdev, name), err);
kobject_put(&ca->kobj);
}
/* Global interfaces/init */
static ssize_t register_bcache(struct kobject *, struct kobj_attribute *,
const char *, size_t);
kobj_attribute_write(register, register_bcache);
kobj_attribute_write(register_quiet, register_bcache);
static bool bch_is_open_backing(struct block_device *bdev) {
struct cache_set *c, *tc;
struct cached_dev *dc, *t;
list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
list_for_each_entry_safe(dc, t, &c->cached_devs, list)
if (dc->bdev == bdev)
return true;
list_for_each_entry_safe(dc, t, &uncached_devices, list)
if (dc->bdev == bdev)
return true;
return false;
}
static bool bch_is_open_cache(struct block_device *bdev) {
struct cache_set *c, *tc;
struct cache *ca;
unsigned i;
list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
for_each_cache(ca, c, i)
if (ca->bdev == bdev)
return true;
return false;
}
static bool bch_is_open(struct block_device *bdev) {
return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
}
static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
const char *buffer, size_t size)
{
ssize_t ret = size;
const char *err = "cannot allocate memory";
char *path = NULL;
struct cache_sb *sb = NULL;
struct block_device *bdev = NULL;
struct page *sb_page = NULL;
if (!try_module_get(THIS_MODULE))
return -EBUSY;
mutex_lock(&bch_register_lock);
if (!(path = kstrndup(buffer, size, GFP_KERNEL)) ||
!(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL)))
goto err;
err = "failed to open device";
bdev = blkdev_get_by_path(strim(path),
FMODE_READ|FMODE_WRITE|FMODE_EXCL,
sb);
if (IS_ERR(bdev)) {
if (bdev == ERR_PTR(-EBUSY)) {
bdev = lookup_bdev(strim(path));
if (!IS_ERR(bdev) && bch_is_open(bdev))
err = "device already registered";
else
err = "device busy";
}
goto err;
}
err = "failed to set blocksize";
if (set_blocksize(bdev, 4096))
goto err_close;
err = read_super(sb, bdev, &sb_page);
if (err)
goto err_close;
if (SB_IS_BDEV(sb)) {
struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
if (!dc)
goto err_close;
register_bdev(sb, sb_page, bdev, dc);
} else {
struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
if (!ca)
goto err_close;
register_cache(sb, sb_page, bdev, ca);
}
out:
if (sb_page)
put_page(sb_page);
kfree(sb);
kfree(path);
mutex_unlock(&bch_register_lock);
module_put(THIS_MODULE);
return ret;
err_close:
blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
err:
if (attr != &ksysfs_register_quiet)
pr_info("error opening %s: %s", path, err);
ret = -EINVAL;
goto out;
}
static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
{
if (code == SYS_DOWN ||
code == SYS_HALT ||
code == SYS_POWER_OFF) {
DEFINE_WAIT(wait);
unsigned long start = jiffies;
bool stopped = false;
struct cache_set *c, *tc;
struct cached_dev *dc, *tdc;
mutex_lock(&bch_register_lock);
if (list_empty(&bch_cache_sets) &&
list_empty(&uncached_devices))
goto out;
pr_info("Stopping all devices:");
list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
bch_cache_set_stop(c);
list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
bcache_device_stop(&dc->disk);
/* What's a condition variable? */
while (1) {
long timeout = start + 2 * HZ - jiffies;
stopped = list_empty(&bch_cache_sets) &&
list_empty(&uncached_devices);
if (timeout < 0 || stopped)
break;
prepare_to_wait(&unregister_wait, &wait,
TASK_UNINTERRUPTIBLE);
mutex_unlock(&bch_register_lock);
schedule_timeout(timeout);
mutex_lock(&bch_register_lock);
}
finish_wait(&unregister_wait, &wait);
if (stopped)
pr_info("All devices stopped");
else
pr_notice("Timeout waiting for devices to be closed");
out:
mutex_unlock(&bch_register_lock);
}
return NOTIFY_DONE;
}
static struct notifier_block reboot = {
.notifier_call = bcache_reboot,
.priority = INT_MAX, /* before any real devices */
};
static void bcache_exit(void)
{
bch_debug_exit();
bch_writeback_exit();
bch_request_exit();
bch_btree_exit();
if (bcache_kobj)
kobject_put(bcache_kobj);
if (bcache_wq)
destroy_workqueue(bcache_wq);
unregister_blkdev(bcache_major, "bcache");
unregister_reboot_notifier(&reboot);
}
static int __init bcache_init(void)
{
static const struct attribute *files[] = {
&ksysfs_register.attr,
&ksysfs_register_quiet.attr,
NULL
};
mutex_init(&bch_register_lock);
init_waitqueue_head(&unregister_wait);
register_reboot_notifier(&reboot);
closure_debug_init();
bcache_major = register_blkdev(0, "bcache");
if (bcache_major < 0)
return bcache_major;
if (!(bcache_wq = create_workqueue("bcache")) ||
!(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) ||
sysfs_create_files(bcache_kobj, files) ||
bch_btree_init() ||
bch_request_init() ||
bch_writeback_init() ||
bch_debug_init(bcache_kobj))
goto err;
return 0;
err:
bcache_exit();
return -ENOMEM;
}
module_exit(bcache_exit);
module_init(bcache_init);