// SPDX-License-Identifier: GPL-2.0
/*
* bcache setup/teardown code, and some metadata io - read a superblock and
* figure out what to do with it.
*
* Copyright 2010, 2011 Kent Overstreet <[email protected]>
* Copyright 2012 Google, Inc.
*/
#include "bcache.h"
#include "btree.h"
#include "debug.h"
#include "extents.h"
#include "request.h"
#include "writeback.h"
#include "features.h"
#include <linux/blkdev.h>
#include <linux/pagemap.h>
#include <linux/debugfs.h>
#include <linux/idr.h>
#include <linux/kthread.h>
#include <linux/workqueue.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/reboot.h>
#include <linux/sysfs.h>
unsigned int bch_cutoff_writeback;
unsigned int bch_cutoff_writeback_sync;
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
};
static struct kobject *bcache_kobj;
struct mutex bch_register_lock;
bool bcache_is_reboot;
LIST_HEAD(bch_cache_sets);
static LIST_HEAD(uncached_devices);
static int bcache_major;
static DEFINE_IDA(bcache_device_idx);
static wait_queue_head_t unregister_wait;
struct workqueue_struct *bcache_wq;
struct workqueue_struct *bch_flush_wq;
struct workqueue_struct *bch_journal_wq;
#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
/* limitation of partitions number on single bcache device */
#define BCACHE_MINORS 128
/* limitation of bcache devices number on single system */
#define BCACHE_DEVICE_IDX_MAX ((1U << MINORBITS)/BCACHE_MINORS)
/* Superblock */
static unsigned int get_bucket_size(struct cache_sb *sb, struct cache_sb_disk *s)
{
unsigned int bucket_size = le16_to_cpu(s->bucket_size);
if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
if (bch_has_feature_large_bucket(sb)) {
unsigned int max, order;
max = sizeof(unsigned int) * BITS_PER_BYTE - 1;
order = le16_to_cpu(s->bucket_size);
/*
* bcache tool will make sure the overflow won't
* happen, an error message here is enough.
*/
if (order > max)
pr_err("Bucket size (1 << %u) overflows\n",
order);
bucket_size = 1 << order;
} else if (bch_has_feature_obso_large_bucket(sb)) {
bucket_size +=
le16_to_cpu(s->obso_bucket_size_hi) << 16;
}
}
return bucket_size;
}
static const char *read_super_common(struct cache_sb *sb, struct block_device *bdev,
struct cache_sb_disk *s)
{
const char *err;
unsigned int i;
sb->first_bucket= le16_to_cpu(s->first_bucket);
sb->nbuckets = le64_to_cpu(s->nbuckets);
sb->bucket_size = get_bucket_size(sb, s);
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 journal buckets";
if (sb->keys > SB_JOURNAL_BUCKETS)
goto err;
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 size (not power of 2)";
if (!is_power_of_2(sb->block_size))
goto err;
err = "Bad block size (larger than page size)";
if (sb->block_size > PAGE_SECTORS)
goto err;
err = "Bad bucket size (not power of 2)";
if (!is_power_of_2(sb->bucket_size))
goto err;
err = "Bad bucket size (smaller than page size)";
if (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;
err = NULL;
err:
return err;
}
static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
struct cache_sb_disk **res)
{
const char *err;
struct cache_sb_disk *s;
struct page *page;
unsigned int i;
page = read_cache_page_gfp(bdev->bd_mapping,
SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
if (IS_ERR(page))
return "IO error";
s = page_address(page) + offset_in_page(SB_OFFSET);
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->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\n",
sb->version, sb->flags, sb->seq, sb->keys);
err = "Not a bcache superblock (bad offset)";
if (sb->offset != SB_SECTOR)
goto err;
err = "Not a bcache superblock (bad magic)";
if (memcmp(sb->magic, bcache_magic, 16))
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:
case BCACHE_SB_VERSION_BDEV_WITH_FEATURES:
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:
err = read_super_common(sb, bdev, s);
if (err)
goto err;
break;
case BCACHE_SB_VERSION_CDEV_WITH_FEATURES:
/*
* Feature bits are needed in read_super_common(),
* convert them firstly.
*/
sb->feature_compat = le64_to_cpu(s->feature_compat);
sb->feature_incompat = le64_to_cpu(s->feature_incompat);
sb->feature_ro_compat = le64_to_cpu(s->feature_ro_compat);
/* Check incompatible features */
err = "Unsupported compatible feature found";
if (bch_has_unknown_compat_features(sb))
goto err;
err = "Unsupported read-only compatible feature found";
if (bch_has_unknown_ro_compat_features(sb))
goto err;
err = "Unsupported incompatible feature found";
if (bch_has_unknown_incompat_features(sb))
goto err;
err = read_super_common(sb, bdev, s);
if (err)
goto err;
break;
default:
err = "Unsupported superblock version";
goto err;
}
sb->last_mount = (u32)ktime_get_real_seconds();
*res = s;
return NULL;
err:
put_page(page);
return err;
}
static void write_bdev_super_endio(struct bio *bio)
{
struct cached_dev *dc = bio->bi_private;
if (bio->bi_status)
bch_count_backing_io_errors(dc, bio);
closure_put(&dc->sb_write);
}
static void __write_super(struct cache_sb *sb, struct cache_sb_disk *out,
struct bio *bio)
{
unsigned int i;
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_META;
bio->bi_iter.bi_sector = SB_SECTOR;
__bio_add_page(bio, virt_to_page(out), SB_SIZE,
offset_in_page(out));
out->offset = cpu_to_le64(sb->offset);
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]);
if (sb->version >= BCACHE_SB_VERSION_CDEV_WITH_FEATURES) {
out->feature_compat = cpu_to_le64(sb->feature_compat);
out->feature_incompat = cpu_to_le64(sb->feature_incompat);
out->feature_ro_compat = cpu_to_le64(sb->feature_ro_compat);
}
out->version = cpu_to_le64(sb->version);
out->csum = csum_set(out);
pr_debug("ver %llu, flags %llu, seq %llu\n",
sb->version, sb->flags, sb->seq);
submit_bio(bio);
}
static CLOSURE_CALLBACK(bch_write_bdev_super_unlock)
{
closure_type(dc, struct cached_dev, sb_write);
up(&dc->sb_write_mutex);
}
void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
{
struct closure *cl = &dc->sb_write;
struct bio *bio = &dc->sb_bio;
down(&dc->sb_write_mutex);
closure_init(cl, parent);
bio_init(bio, dc->bdev, dc->sb_bv, 1, 0);
bio->bi_end_io = write_bdev_super_endio;
bio->bi_private = dc;
closure_get(cl);
/* I/O request sent to backing device */
__write_super(&dc->sb, dc->sb_disk, bio);
closure_return_with_destructor(cl, bch_write_bdev_super_unlock);
}
static void write_super_endio(struct bio *bio)
{
struct cache *ca = bio->bi_private;
/* is_read = 0 */
bch_count_io_errors(ca, bio->bi_status, 0,
"writing superblock");
closure_put(&ca->set->sb_write);
}
static CLOSURE_CALLBACK(bcache_write_super_unlock)
{
closure_type(c, struct cache_set, sb_write);
up(&c->sb_write_mutex);
}
void bcache_write_super(struct cache_set *c)
{
struct closure *cl = &c->sb_write;
struct cache *ca = c->cache;
struct bio *bio = &ca->sb_bio;
unsigned int version = BCACHE_SB_VERSION_CDEV_WITH_UUID;
down(&c->sb_write_mutex);
closure_init(cl, &c->cl);
ca->sb.seq++;
if (ca->sb.version < version)
ca->sb.version = version;
bio_init(bio, ca->bdev, ca->sb_bv, 1, 0);
bio->bi_end_io = write_super_endio;
bio->bi_private = ca;
closure_get(cl);
__write_super(&ca->sb, ca->sb_disk, bio);
closure_return_with_destructor(cl, bcache_write_super_unlock);
}
/* UUID io */
static void uuid_endio(struct bio *bio)
{
struct closure *cl = bio->bi_private;
struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
cache_set_err_on(bio->bi_status, c, "accessing uuids");
bch_bbio_free(bio, c);
closure_put(cl);
}
static CLOSURE_CALLBACK(uuid_io_unlock)
{
closure_type(c, struct cache_set, uuid_write);
up(&c->uuid_write_mutex);
}
static void uuid_io(struct cache_set *c, blk_opf_t opf, struct bkey *k,
struct closure *parent)
{
struct closure *cl = &c->uuid_write;
struct uuid_entry *u;
unsigned int i;
char buf[80];
BUG_ON(!parent);
down(&c->uuid_write_mutex);
closure_init(cl, parent);
for (i = 0; i < KEY_PTRS(k); i++) {
struct bio *bio = bch_bbio_alloc(c);
bio->bi_opf = opf | REQ_SYNC | REQ_META;
bio->bi_iter.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 ((opf & REQ_OP_MASK) != REQ_OP_WRITE)
break;
}
bch_extent_to_text(buf, sizeof(buf), k);
pr_debug("%s UUIDs at %s\n", (opf & REQ_OP_MASK) == REQ_OP_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\n",
u - c->uuids, u->uuid, u->label,
u->first_reg, u->last_reg, u->invalidated);
closure_return_with_destructor(cl, uuid_io_unlock);
}
static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
{
struct bkey *k = &j->uuid_bucket;
if (__bch_btree_ptr_invalid(c, k))
return "bad uuid pointer";
bkey_copy(&c->uuid_bucket, k);
uuid_io(c, REQ_OP_READ, 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;
struct cache *ca = c->cache;
unsigned int size;
closure_init_stack(&cl);
lockdep_assert_held(&bch_register_lock);
if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
return 1;
size = meta_bucket_pages(&ca->sb) * PAGE_SECTORS;
SET_KEY_SIZE(&k.key, size);
uuid_io(c, REQ_OP_WRITE, &k.key, &cl);
closure_sync(&cl);
/* Only one bucket used for uuid write */
atomic_long_add(ca->sb.bucket_size, &ca->meta_sectors_written);
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)
{
struct cache *ca = bio->bi_private;
cache_set_err_on(bio->bi_status, ca->set, "accessing priorities");
bch_bbio_free(bio, ca->set);
closure_put(&ca->prio);
}
static void prio_io(struct cache *ca, uint64_t bucket, blk_opf_t opf)
{
struct closure *cl = &ca->prio;
struct bio *bio = bch_bbio_alloc(ca->set);
closure_init_stack(cl);
bio->bi_iter.bi_sector = bucket * ca->sb.bucket_size;
bio_set_dev(bio, ca->bdev);
bio->bi_iter.bi_size = meta_bucket_bytes(&ca->sb);
bio->bi_end_io = prio_endio;
bio->bi_private = ca;
bio->bi_opf = opf | REQ_SYNC | REQ_META;
bch_bio_map(bio, ca->disk_buckets);
closure_bio_submit(ca->set, bio, &ca->prio);
closure_sync(cl);
}
int bch_prio_write(struct cache *ca, bool wait)
{
int i;
struct bucket *b;
struct closure cl;
pr_debug("free_prio=%zu, free_none=%zu, free_inc=%zu\n",
fifo_used(&ca->free[RESERVE_PRIO]),
fifo_used(&ca->free[RESERVE_NONE]),
fifo_used(&ca->free_inc));
/*
* Pre-check if there are enough free buckets. In the non-blocking
* scenario it's better to fail early rather than starting to allocate
* buckets and do a cleanup later in case of failure.
*/
if (!wait) {
size_t avail = fifo_used(&ca->free[RESERVE_PRIO]) +
fifo_used(&ca->free[RESERVE_NONE]);
if (prio_buckets(ca) > avail)
return -ENOMEM;
}
closure_init_stack(&cl);
lockdep_assert_held(&ca->set->bucket_lock);
ca->disk_buckets->seq++;
atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
&ca->meta_sectors_written);
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->sb);
p->csum = bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8);
bucket = bch_bucket_alloc(ca, RESERVE_PRIO, wait);
BUG_ON(bucket == -1);
mutex_unlock(&ca->set->bucket_lock);
prio_io(ca, bucket, REQ_OP_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);
/*
* 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++) {
if (ca->prio_last_buckets[i])
__bch_bucket_free(ca,
&ca->buckets[ca->prio_last_buckets[i]]);
ca->prio_last_buckets[i] = ca->prio_buckets[i];
}
return 0;
}
static int 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 int bucket_nr = 0;
int ret = -EIO;
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, REQ_OP_READ);
if (p->csum !=
bch_crc64(&p->magic, meta_bucket_bytes(&ca->sb) - 8)) {
pr_warn("bad csum reading priorities\n");
goto out;
}
if (p->magic != pset_magic(&ca->sb)) {
pr_warn("bad magic reading priorities\n");
goto out;
}
bucket = p->next_bucket;
d = p->data;
}
b->prio = le16_to_cpu(d->prio);
b->gen = b->last_gc = d->gen;
}
ret = 0;
out:
return ret;
}
/* Bcache device */
static int open_dev(struct gendisk *disk, blk_mode_t mode)
{
struct bcache_device *d = disk->private_data;
if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
return -ENXIO;
closure_get(&d->cl);
return 0;
}
static void release_dev(struct gendisk *b)
{
struct bcache_device *d = b->private_data;
closure_put(&d->cl);
}
static int ioctl_dev(struct block_device *b, blk_mode_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_cached_ops = {
.submit_bio = cached_dev_submit_bio,
.open = open_dev,
.release = release_dev,
.ioctl = ioctl_dev,
.owner = THIS_MODULE,
};
static const struct block_device_operations bcache_flash_ops = {
.submit_bio = flash_dev_submit_bio,
.open = open_dev,
.release = release_dev,
.ioctl = ioctl_dev,
.owner = THIS_MODULE,
};
void bcache_device_stop(struct bcache_device *d)
{
if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
/*
* closure_fn set to
* - cached device: cached_dev_flush()
* - flash dev: flash_dev_flush()
*/
closure_queue(&d->cl);
}
static void bcache_device_unlink(struct bcache_device *d)
{
lockdep_assert_held(&bch_register_lock);
if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
struct cache *ca = d->c->cache;
sysfs_remove_link(&d->c->kobj, d->name);
sysfs_remove_link(&d->kobj, "cache");
bd_unlink_disk_holder(ca->bdev, d->disk);
}
}
static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
const char *name)
{
struct cache *ca = c->cache;
int ret;
bd_link_disk_holder(ca->bdev, d->disk);
snprintf(d->name, BCACHEDEVNAME_SIZE,
"%s%u", name, d->id);
ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
if (ret < 0)
pr_err("Couldn't create device -> cache set symlink\n");
ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
if (ret < 0)
pr_err("Couldn't create cache set -> device symlink\n");
clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
}
static void bcache_device_detach(struct bcache_device *d)
{
lockdep_assert_held(&bch_register_lock);
atomic_dec(&d->c->attached_dev_nr);
if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
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((u32)ktime_get_real_seconds());
bch_uuid_write(d->c);
}
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 int id)
{
d->id = id;
d->c = c;
c->devices[id] = d;
if (id >= c->devices_max_used)
c->devices_max_used = id + 1;
closure_get(&c->caching);
}
static inline int first_minor_to_idx(int first_minor)
{
return (first_minor/BCACHE_MINORS);
}
static inline int idx_to_first_minor(int idx)
{
return (idx * BCACHE_MINORS);
}
static void bcache_device_free(struct bcache_device *d)
{
struct gendisk *disk = d->disk;
lockdep_assert_held(&bch_register_lock);
if (disk)
pr_info("%s stopped\n", disk->disk_name);
else
pr_err("bcache device (NULL gendisk) stopped\n");
if (d->c)
bcache_device_detach(d);
if (disk) {
ida_free(&bcache_device_idx,
first_minor_to_idx(disk->first_minor));
put_disk(disk);
}
bioset_exit(&d->bio_split);
kvfree(d->full_dirty_stripes);
kvfree(d->stripe_sectors_dirty);
closure_debug_destroy(&d->cl);
}
static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
sector_t sectors, struct block_device *cached_bdev,
const struct block_device_operations *ops)
{
const size_t max_stripes = min_t(size_t, INT_MAX,
SIZE_MAX / sizeof(atomic_t));
struct queue_limits lim = {
.max_hw_sectors = UINT_MAX,
.max_sectors = UINT_MAX,
.max_segment_size = UINT_MAX,
.max_segments = BIO_MAX_VECS,
.max_hw_discard_sectors = UINT_MAX,
.io_min = block_size,
.logical_block_size = block_size,
.physical_block_size = block_size,
.features = BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA,
};
uint64_t n;
int idx;
if (cached_bdev) {
d->stripe_size = bdev_io_opt(cached_bdev) >> SECTOR_SHIFT;
lim.io_opt = umax(block_size, bdev_io_opt(cached_bdev));
}
if (!d->stripe_size)
d->stripe_size = 1 << 31;
else if (d->stripe_size < BCH_MIN_STRIPE_SZ)
d->stripe_size = roundup(BCH_MIN_STRIPE_SZ, d->stripe_size);
n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
if (!n || n > max_stripes) {
pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
n);
return -ENOMEM;
}
d->nr_stripes = n;
n = d->nr_stripes * sizeof(atomic_t);
d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
if (!d->stripe_sectors_dirty)
return -ENOMEM;
n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
if (!d->full_dirty_stripes)
goto out_free_stripe_sectors_dirty;
idx = ida_alloc_max(&bcache_device_idx, BCACHE_DEVICE_IDX_MAX - 1,
GFP_KERNEL);
if (idx < 0)
goto out_free_full_dirty_stripes;
if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
goto out_ida_remove;
if (lim.logical_block_size > PAGE_SIZE && cached_bdev) {
/*
* This should only happen with BCACHE_SB_VERSION_BDEV.
* Block/page size is checked for BCACHE_SB_VERSION_CDEV.
*/
pr_info("bcache%i: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
idx, lim.logical_block_size,
PAGE_SIZE, bdev_logical_block_size(cached_bdev));
/* This also adjusts physical block size/min io size if needed */
lim.logical_block_size = bdev_logical_block_size(cached_bdev);
}
d->disk = blk_alloc_disk(&lim, NUMA_NO_NODE);
if (IS_ERR(d->disk))
goto out_bioset_exit;
set_capacity(d->disk, sectors);
snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", idx);
d->disk->major = bcache_major;
d->disk->first_minor = idx_to_first_minor(idx);
d->disk->minors = BCACHE_MINORS;
d->disk->fops = ops;
d->disk->private_data = d;
return 0;
out_bioset_exit:
bioset_exit(&d->bio_split);
out_ida_remove:
ida_free(&bcache_device_idx, idx);
out_free_full_dirty_stripes:
kvfree(d->full_dirty_stripes);
out_free_stripe_sectors_dirty:
kvfree(d->stripe_sectors_dirty);
return -ENOMEM;
}
/* 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_nr_sectors(dc->bdev);
c->cached_dev_sectors = sectors;
}
#define BACKING_DEV_OFFLINE_TIMEOUT 5
static int cached_dev_status_update(void *arg)
{
struct cached_dev *dc = arg;
struct request_queue *q;
/*
* If this delayed worker is stopping outside, directly quit here.
* dc->io_disable might be set via sysfs interface, so check it
* here too.
*/
while (!kthread_should_stop() && !dc->io_disable) {
q = bdev_get_queue(dc->bdev);
if (blk_queue_dying(q))
dc->offline_seconds++;
else
dc->offline_seconds = 0;
if (dc->offline_seconds >= BACKING_DEV_OFFLINE_TIMEOUT) {
pr_err("%pg: device offline for %d seconds\n",
dc->bdev,
BACKING_DEV_OFFLINE_TIMEOUT);
pr_err("%s: disable I/O request due to backing device offline\n",
dc->disk.name);
dc->io_disable = true;
/* let others know earlier that io_disable is true */
smp_mb();
bcache_device_stop(&dc->disk);
break;
}
schedule_timeout_interruptible(HZ);
}
wait_for_kthread_stop();
return 0;
}
int bch_cached_dev_run(struct cached_dev *dc)
{
int ret = 0;
struct bcache_device *d = &dc->disk;
char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
char *env[] = {
"DRIVER=bcache",
kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
NULL,
};
if (dc->io_disable) {
pr_err("I/O disabled on cached dev %pg\n", dc->bdev);
ret = -EIO;
goto out;
}
if (atomic_xchg(&dc->running, 1)) {
pr_info("cached dev %pg is running already\n", dc->bdev);
ret = -EBUSY;
goto out;
}
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);
}
ret = add_disk(d->disk);
if (ret)
goto out;
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);
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_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
ret = -ENOMEM;
goto out;
}
dc->status_update_thread = kthread_run(cached_dev_status_update,
dc, "bcache_status_update");
if (IS_ERR(dc->status_update_thread)) {
pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
}
out:
kfree(env[1]);
kfree(env[2]);
kfree(buf);
return ret;
}
/*
* If BCACHE_DEV_RATE_DW_RUNNING is set, it means routine of the delayed
* work dc->writeback_rate_update is running. Wait until the routine
* quits (BCACHE_DEV_RATE_DW_RUNNING is clear), then continue to
* cancel it. If BCACHE_DEV_RATE_DW_RUNNING is not clear after time_out
* seconds, give up waiting here and continue to cancel it too.
*/
static void cancel_writeback_rate_update_dwork(struct cached_dev *dc)
{
int time_out = WRITEBACK_RATE_UPDATE_SECS_MAX * HZ;
do {
if (!test_bit(BCACHE_DEV_RATE_DW_RUNNING,
&dc->disk.flags))
break;
time_out--;
schedule_timeout_interruptible(1);
} while (time_out > 0);
if (time_out == 0)
pr_warn("give up waiting for dc->writeback_write_update to quit\n");
cancel_delayed_work_sync(&dc->writeback_rate_update);
}
static void cached_dev_detach_finish(struct work_struct *w)
{
struct cached_dev *dc = container_of(w, struct cached_dev, detach);
struct cache_set *c = dc->disk.c;
BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
BUG_ON(refcount_read(&dc->count));
if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
cancel_writeback_rate_update_dwork(dc);
if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
kthread_stop(dc->writeback_thread);
dc->writeback_thread = NULL;
}
mutex_lock(&bch_register_lock);
bcache_device_detach(&dc->disk);
list_move(&dc->list, &uncached_devices);
calc_cached_dev_sectors(c);
clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
clear_bit(BCACHE_DEV_UNLINK_DONE, &dc->disk.flags);
mutex_unlock(&bch_register_lock);
pr_info("Caching disabled for %pg\n", dc->bdev);
/* 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 (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
return;
if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
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,
uint8_t *set_uuid)
{
uint32_t rtime = cpu_to_le32((u32)ktime_get_real_seconds());
struct uuid_entry *u;
struct cached_dev *exist_dc, *t;
int ret = 0;
if ((set_uuid && memcmp(set_uuid, c->set_uuid, 16)) ||
(!set_uuid && memcmp(dc->sb.set_uuid, c->set_uuid, 16)))
return -ENOENT;
if (dc->disk.c) {
pr_err("Can't attach %pg: already attached\n", dc->bdev);
return -EINVAL;
}
if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
pr_err("Can't attach %pg: shutting down\n", dc->bdev);
return -EINVAL;
}
if (dc->sb.block_size < c->cache->sb.block_size) {
/* Will die */
pr_err("Couldn't attach %pg: block size less than set's block size\n",
dc->bdev);
return -EINVAL;
}
/* Check whether already attached */
list_for_each_entry_safe(exist_dc, t, &c->cached_devs, list) {
if (!memcmp(dc->sb.uuid, exist_dc->sb.uuid, 16)) {
pr_err("Tried to attach %pg but duplicate UUID already attached\n",
dc->bdev);
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((u32)ktime_get_real_seconds());
u = NULL;
}
if (!u) {
if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
pr_err("Couldn't find uuid for %pg in set\n", dc->bdev);
return -ENOENT;
}
u = uuid_find_empty(c);
if (!u) {
pr_err("Not caching %pg, no room for UUID\n", dc->bdev);
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->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);
/*
* dc->c must be set before dc->count != 0 - paired with the mb in
* cached_dev_get()
*/
smp_wmb();
refcount_set(&dc->count, 1);
/* Block writeback thread, but spawn it */
down_write(&dc->writeback_lock);
if (bch_cached_dev_writeback_start(dc)) {
up_write(&dc->writeback_lock);
pr_err("Couldn't start writeback facilities for %s\n",
dc->disk.disk->disk_name);
return -ENOMEM;
}
if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
atomic_set(&dc->has_dirty, 1);
bch_writeback_queue(dc);
}
bch_sectors_dirty_init(&dc->disk);
ret = bch_cached_dev_run(dc);
if (ret && (ret != -EBUSY)) {
up_write(&dc->writeback_lock);
/*
* bch_register_lock is held, bcache_device_stop() is not
* able to be directly called. The kthread and kworker
* created previously in bch_cached_dev_writeback_start()
* have to be stopped manually here.
*/
kthread_stop(dc->writeback_thread);
cancel_writeback_rate_update_dwork(dc);
pr_err("Couldn't run cached device %pg\n", dc->bdev);
return ret;
}
bcache_device_link(&dc->disk, c, "bdev");
atomic_inc(&c->attached_dev_nr);
if (bch_has_feature_obso_large_bucket(&(c->cache->sb))) {
pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
pr_err("Please update to the latest bcache-tools to create the cache device\n");
set_disk_ro(dc->disk.disk, 1);
}
/* Allow the writeback thread to proceed */
up_write(&dc->writeback_lock);
pr_info("Caching %pg as %s on set %pU\n",
dc->bdev,
dc->disk.disk->disk_name,
dc->disk.c->set_uuid);
return 0;
}
/* when dc->disk.kobj released */
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 CLOSURE_CALLBACK(cached_dev_free)
{
closure_type(dc, struct cached_dev, disk.cl);
if (test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags))
cancel_writeback_rate_update_dwork(dc);
if (!IS_ERR_OR_NULL(dc->writeback_thread))
kthread_stop(dc->writeback_thread);
if (!IS_ERR_OR_NULL(dc->status_update_thread))
kthread_stop(dc->status_update_thread);
mutex_lock(&bch_register_lock);
if (atomic_read(&dc->running)) {
bd_unlink_disk_holder(dc->bdev, dc->disk.disk);
del_gendisk(dc->disk.disk);
}
bcache_device_free(&dc->disk);
list_del(&dc->list);
mutex_unlock(&bch_register_lock);
if (dc->sb_disk)
put_page(virt_to_page(dc->sb_disk));
if (dc->bdev_file)
fput(dc->bdev_file);
wake_up(&unregister_wait);
kobject_put(&dc->disk.kobj);
}
static CLOSURE_CALLBACK(cached_dev_flush)
{
closure_type(dc, struct cached_dev, disk.cl);
struct bcache_device *d = &dc->disk;
mutex_lock(&bch_register_lock);
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 int 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);
sema_init(&dc->sb_write_mutex, 1);
INIT_LIST_HEAD(&dc->io_lru);
spin_lock_init(&dc->io_lock);
bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
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);
}
if (bdev_io_opt(dc->bdev))
dc->partial_stripes_expensive = !!(q->limits.features &
BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE);
ret = bcache_device_init(&dc->disk, block_size,
bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
dc->bdev, &bcache_cached_ops);
if (ret)
return ret;
atomic_set(&dc->io_errors, 0);
dc->io_disable = false;
dc->error_limit = DEFAULT_CACHED_DEV_ERROR_LIMIT;
/* default to auto */
dc->stop_when_cache_set_failed = BCH_CACHED_DEV_STOP_AUTO;
bch_cached_dev_request_init(dc);
bch_cached_dev_writeback_init(dc);
return 0;
}
/* Cached device - bcache superblock */
static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
struct file *bdev_file,
struct cached_dev *dc)
{
const char *err = "cannot allocate memory";
struct cache_set *c;
int ret = -ENOMEM;
memcpy(&dc->sb, sb, sizeof(struct cache_sb));
dc->bdev_file = bdev_file;
dc->bdev = file_bdev(bdev_file);
dc->sb_disk = sb_disk;
if (cached_dev_init(dc, sb->block_size << 9))
goto err;
err = "error creating kobject";
if (kobject_add(&dc->disk.kobj, bdev_kobj(dc->bdev), "bcache"))
goto err;
if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
goto err;
pr_info("registered backing device %pg\n", dc->bdev);
list_add(&dc->list, &uncached_devices);
/* attach to a matched cache set if it exists */
list_for_each_entry(c, &bch_cache_sets, list)
bch_cached_dev_attach(dc, c, NULL);
if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
BDEV_STATE(&dc->sb) == BDEV_STATE_STALE) {
err = "failed to run cached device";
ret = bch_cached_dev_run(dc);
if (ret)
goto err;
}
return 0;
err:
pr_notice("error %pg: %s\n", dc->bdev, err);
bcache_device_stop(&dc->disk);
return ret;
}
/* Flash only volumes */
/* When d->kobj released */
void bch_flash_dev_release(struct kobject *kobj)
{
struct bcache_device *d = container_of(kobj, struct bcache_device,
kobj);
kfree(d);
}
static CLOSURE_CALLBACK(flash_dev_free)
{
closure_type(d, struct bcache_device, cl);
mutex_lock(&bch_register_lock);
atomic_long_sub(bcache_dev_sectors_dirty(d),
&d->c->flash_dev_dirty_sectors);
del_gendisk(d->disk);
bcache_device_free(d);
mutex_unlock(&bch_register_lock);
kobject_put(&d->kobj);
}
static CLOSURE_CALLBACK(flash_dev_flush)
{
closure_type(d, struct bcache_device, cl);
mutex_lock(&bch_register_lock);
bcache_device_unlink(d);
mutex_unlock(&bch_register_lock);
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)
{
int err = -ENOMEM;
struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
GFP_KERNEL);
if (!d)
goto err_ret;
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->cache), u->sectors,
NULL, &bcache_flash_ops))
goto err;
bcache_device_attach(d, c, u - c->uuids);
bch_sectors_dirty_init(d);
bch_flash_dev_request_init(d);
err = add_disk(d->disk);
if (err)
goto err;
err = kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache");
if (err)
goto err;
bcache_device_link(d, c, "volume");
if (bch_has_feature_obso_large_bucket(&c->cache->sb)) {
pr_err("The obsoleted large bucket layout is unsupported, set the bcache device into read-only\n");
pr_err("Please update to the latest bcache-tools to create the cache device\n");
set_disk_ro(d->disk, 1);
}
return 0;
err:
kobject_put(&d->kobj);
err_ret:
return err;
}
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;
if (!test_bit(CACHE_SET_RUNNING, &c->flags))
return -EPERM;
u = uuid_find_empty(c);
if (!u) {
pr_err("Can't create volume, no room for UUID\n");
return -EINVAL;
}
get_random_bytes(u->uuid, 16);
memset(u->label, 0, 32);
u->first_reg = u->last_reg = cpu_to_le32((u32)ktime_get_real_seconds());
SET_UUID_FLASH_ONLY(u, 1);
u->sectors = size >> 9;
bch_uuid_write(c);
return flash_dev_run(c, u);
}
bool bch_cached_dev_error(struct cached_dev *dc)
{
if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
return false;
dc->io_disable = true;
/* make others know io_disable is true earlier */
smp_mb();
pr_err("stop %s: too many IO errors on backing device %pg\n",
dc->disk.disk->disk_name, dc->bdev);
bcache_device_stop(&dc->disk);
return true;
}
/* Cache set */
__printf(2, 3)
bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
if (c->on_error != ON_ERROR_PANIC &&
test_bit(CACHE_SET_STOPPING, &c->flags))
return false;
if (test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
pr_info("CACHE_SET_IO_DISABLE already set\n");
/*
* XXX: we can be called from atomic context
* acquire_console_sem();
*/
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
pr_err("error on %pU: %pV, disabling caching\n",
c->set_uuid, &vaf);
va_end(args);
if (c->on_error == ON_ERROR_PANIC)
panic("panic forced after error\n");
bch_cache_set_unregister(c);
return true;
}
/* When c->kobj released */
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 CLOSURE_CALLBACK(cache_set_free)
{
closure_type(c, struct cache_set, cl);
struct cache *ca;
debugfs_remove(c->debug);
bch_open_buckets_free(c);
bch_btree_cache_free(c);
bch_journal_free(c);
mutex_lock(&bch_register_lock);
bch_bset_sort_state_free(&c->sort);
free_pages((unsigned long) c->uuids, ilog2(meta_bucket_pages(&c->cache->sb)));
ca = c->cache;
if (ca) {
ca->set = NULL;
c->cache = NULL;
kobject_put(&ca->kobj);
}
if (c->moving_gc_wq)
destroy_workqueue(c->moving_gc_wq);
bioset_exit(&c->bio_split);
mempool_exit(&c->fill_iter);
mempool_exit(&c->bio_meta);
mempool_exit(&c->search);
kfree(c->devices);
list_del(&c->list);
mutex_unlock(&bch_register_lock);
pr_info("Cache set %pU unregistered\n", c->set_uuid);
wake_up(&unregister_wait);
closure_debug_destroy(&c->cl);
kobject_put(&c->kobj);
}
static CLOSURE_CALLBACK(cache_set_flush)
{
closure_type(c, struct cache_set, caching);
struct cache *ca = c->cache;
struct btree *b;
bch_cache_accounting_destroy(&c->accounting);
kobject_put(&c->internal);
kobject_del(&c->kobj);
if (!IS_ERR_OR_NULL(c->gc_thread))
kthread_stop(c->gc_thread);
if (!IS_ERR(c->root))
list_add(&c->root->list, &c->btree_cache);
/*
* Avoid flushing cached nodes if cache set is retiring
* due to too many I/O errors detected.
*/
if (!test_bit(CACHE_SET_IO_DISABLE, &c->flags))
list_for_each_entry(b, &c->btree_cache, list) {
mutex_lock(&b->write_lock);
if (btree_node_dirty(b))
__bch_btree_node_write(b, NULL);
mutex_unlock(&b->write_lock);
}
if (ca->alloc_thread)
kthread_stop(ca->alloc_thread);
if (c->journal.cur) {
cancel_delayed_work_sync(&c->journal.work);
/* flush last journal entry if needed */
c->journal.work.work.func(&c->journal.work.work);
}
closure_return(cl);
}
/*
* This function is only called when CACHE_SET_IO_DISABLE is set, which means
* cache set is unregistering due to too many I/O errors. In this condition,
* the bcache device might be stopped, it depends on stop_when_cache_set_failed
* value and whether the broken cache has dirty data:
*
* dc->stop_when_cache_set_failed dc->has_dirty stop bcache device
* BCH_CACHED_STOP_AUTO 0 NO
* BCH_CACHED_STOP_AUTO 1 YES
* BCH_CACHED_DEV_STOP_ALWAYS 0 YES
* BCH_CACHED_DEV_STOP_ALWAYS 1 YES
*
* The expected behavior is, if stop_when_cache_set_failed is configured to
* "auto" via sysfs interface, the bcache device will not be stopped if the
* backing device is clean on the broken cache device.
*/
static void conditional_stop_bcache_device(struct cache_set *c,
struct bcache_device *d,
struct cached_dev *dc)
{
if (dc->stop_when_cache_set_failed == BCH_CACHED_DEV_STOP_ALWAYS) {
pr_warn("stop_when_cache_set_failed of %s is \"always\", stop it for failed cache set %pU.\n",
d->disk->disk_name, c->set_uuid);
bcache_device_stop(d);
} else if (atomic_read(&dc->has_dirty)) {
/*
* dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
* and dc->has_dirty == 1
*/
pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is dirty, stop it to avoid potential data corruption.\n",
d->disk->disk_name);
/*
* There might be a small time gap that cache set is
* released but bcache device is not. Inside this time
* gap, regular I/O requests will directly go into
* backing device as no cache set attached to. This
* behavior may also introduce potential inconsistence
* data in writeback mode while cache is dirty.
* Therefore before calling bcache_device_stop() due
* to a broken cache device, dc->io_disable should be
* explicitly set to true.
*/
dc->io_disable = true;
/* make others know io_disable is true earlier */
smp_mb();
bcache_device_stop(d);
} else {
/*
* dc->stop_when_cache_set_failed == BCH_CACHED_STOP_AUTO
* and dc->has_dirty == 0
*/
pr_warn("stop_when_cache_set_failed of %s is \"auto\" and cache is clean, keep it alive.\n",
d->disk->disk_name);
}
}
static CLOSURE_CALLBACK(__cache_set_unregister)
{
closure_type(c, struct cache_set, caching);
struct cached_dev *dc;
struct bcache_device *d;
size_t i;
mutex_lock(&bch_register_lock);
for (i = 0; i < c->devices_max_used; i++) {
d = c->devices[i];
if (!d)
continue;
if (!UUID_FLASH_ONLY(&c->uuids[i]) &&
test_bit(CACHE_SET_UNREGISTERING, &c->flags)) {
dc = container_of(d, struct cached_dev, disk);
bch_cached_dev_detach(dc);
if (test_bit(CACHE_SET_IO_DISABLE, &c->flags))
conditional_stop_bcache_device(c, d, dc);
} else {
bcache_device_stop(d);
}
}
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_fn set to __cache_set_unregister() */
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_meta_bucket_pages(gfp, sb) \
((void *) __get_free_pages(__GFP_ZERO|__GFP_COMP|gfp, ilog2(meta_bucket_pages(sb))))
struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
{
int iter_size;
struct cache *ca = container_of(sb, struct cache, sb);
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->set_uuid, sb->set_uuid, 16);
c->cache = ca;
c->cache->set = c;
c->bucket_bits = ilog2(sb->bucket_size);
c->block_bits = ilog2(sb->block_size);
c->nr_uuids = meta_bucket_bytes(sb) / sizeof(struct uuid_entry);
c->devices_max_used = 0;
atomic_set(&c->attached_dev_nr, 0);
c->btree_pages = meta_bucket_pages(sb);
if (c->btree_pages > BTREE_MAX_PAGES)
c->btree_pages = max_t(int, c->btree_pages / 4,
BTREE_MAX_PAGES);
sema_init(&c->sb_write_mutex, 1);
mutex_init(&c->bucket_lock);
init_waitqueue_head(&c->btree_cache_wait);
spin_lock_init(&c->btree_cannibalize_lock);
init_waitqueue_head(&c->bucket_wait);
init_waitqueue_head(&c->gc_wait);
sema_init(&c->uuid_write_mutex, 1);
spin_lock_init(&c->btree_gc_time.lock);
spin_lock_init(&c->btree_split_time.lock);
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);
iter_size = ((meta_bucket_pages(sb) * PAGE_SECTORS) / sb->block_size) *
sizeof(struct btree_iter_set);
c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL);
if (!c->devices)
goto err;
if (mempool_init_slab_pool(&c->search, 32, bch_search_cache))
goto err;
if (mempool_init_kmalloc_pool(&c->bio_meta, 2,
sizeof(struct bbio) +
sizeof(struct bio_vec) * meta_bucket_pages(sb)))
goto err;
if (mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size))
goto err;
if (bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
BIOSET_NEED_RESCUER))
goto err;
c->uuids = alloc_meta_bucket_pages(GFP_KERNEL, sb);
if (!c->uuids)
goto err;
c->moving_gc_wq = alloc_workqueue("bcache_gc", WQ_MEM_RECLAIM, 0);
if (!c->moving_gc_wq)
goto err;
if (bch_journal_alloc(c))
goto err;
if (bch_btree_cache_alloc(c))
goto err;
if (bch_open_buckets_alloc(c))
goto err;
if (bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
goto err;
c->congested_read_threshold_us = 2000;
c->congested_write_threshold_us = 20000;
c->error_limit = DEFAULT_IO_ERROR_LIMIT;
c->idle_max_writeback_rate_enabled = 1;
WARN_ON(test_and_clear_bit(CACHE_SET_IO_DISABLE, &c->flags));
return c;
err:
bch_cache_set_unregister(c);
return NULL;
}
static int run_cache_set(struct cache_set *c)
{
const char *err = "cannot allocate memory";
struct cached_dev *dc, *t;
struct cache *ca = c->cache;
struct closure cl;
LIST_HEAD(journal);
struct journal_replay *l;
closure_init_stack(&cl);
c->nbuckets = ca->sb.nbuckets;
set_gc_sectors(c);
if (CACHE_SYNC(&c->cache->sb)) {
struct bkey *k;
struct jset *j;
err = "cannot allocate memory for journal";
if (bch_journal_read(c, &journal))
goto err;
pr_debug("btree_journal_read() done\n");
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";
if (prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]))
goto err;
/*
* 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_btree_ptr_invalid(c, k))
goto err;
err = "error reading btree root";
c->root = bch_btree_node_get(c, NULL, k,
j->btree_level,
true, NULL);
if (IS_ERR(c->root))
goto err;
list_del_init(&c->root->list);
rw_unlock(true, c->root);
err = uuid_read(c, j, &cl);
if (err)
goto err;
err = "error in recovery";
if (bch_btree_check(c))
goto err;
bch_journal_mark(c, &journal);
bch_initial_gc_finish(c);
pr_debug("btree_check() done\n");
/*
* 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";
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);
err = "bcache: replay journal failed";
if (bch_journal_replay(c, &journal))
goto err;
} else {
unsigned int j;
pr_notice("invalidating existing data\n");
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_initial_gc_finish(c);
err = "error starting allocator thread";
if (bch_cache_allocator_start(ca))
goto err;
mutex_lock(&c->bucket_lock);
bch_prio_write(ca, true);
mutex_unlock(&c->bucket_lock);
err = "cannot allocate new UUID bucket";
if (__uuid_write(c))
goto err;
err = "cannot allocate new btree root";
c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
if (IS_ERR(c->root))
goto err;
mutex_lock(&c->root->write_lock);
bkey_copy_key(&c->root->key, &MAX_KEY);
bch_btree_node_write(c->root, &cl);
mutex_unlock(&c->root->write_lock);
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->cache->sb, true);
bch_journal_next(&c->journal);
bch_journal_meta(c, &cl);
}
err = "error starting gc thread";
if (bch_gc_thread_start(c))
goto err;
closure_sync(&cl);
c->cache->sb.last_mount = (u32)ktime_get_real_seconds();
bcache_write_super(c);
if (bch_has_feature_obso_large_bucket(&c->cache->sb))
pr_err("Detect obsoleted large bucket layout, all attached bcache device will be read-only\n");
list_for_each_entry_safe(dc, t, &uncached_devices, list)
bch_cached_dev_attach(dc, c, NULL);
flash_devs_run(c);
bch_journal_space_reserve(&c->journal);
set_bit(CACHE_SET_RUNNING, &c->flags);
return 0;
err:
while (!list_empty(&journal)) {
l = list_first_entry(&journal, struct journal_replay, list);
list_del(&l->list);
kfree(l);
}
closure_sync(&cl);
bch_cache_set_error(c, "%s", err);
return -EIO;
}
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->set_uuid, ca->sb.set_uuid, 16)) {
if (c->cache)
return "duplicate cache set member";
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->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;
kobject_get(&ca->kobj);
ca->set = c;
ca->set->cache = ca;
err = "failed to run cache set";
if (run_cache_set(c) < 0)
goto err;
return NULL;
err:
bch_cache_set_unregister(c);
return err;
}
/* Cache device */
/* When ca->kobj released */
void bch_cache_release(struct kobject *kobj)
{
struct cache *ca = container_of(kobj, struct cache, kobj);
unsigned int i;
if (ca->set) {
BUG_ON(ca->set->cache != ca);
ca->set->cache = NULL;
}
free_pages((unsigned long) ca->disk_buckets, ilog2(meta_bucket_pages(&ca->sb)));
kfree(ca->prio_buckets);
vfree(ca->buckets);
free_heap(&ca->heap);
free_fifo(&ca->free_inc);
for (i = 0; i < RESERVE_NR; i++)
free_fifo(&ca->free[i]);
if (ca->sb_disk)
put_page(virt_to_page(ca->sb_disk));
if (ca->bdev_file)
fput(ca->bdev_file);
kfree(ca);
module_put(THIS_MODULE);
}
static int cache_alloc(struct cache *ca)
{
size_t free;
size_t btree_buckets;
struct bucket *b;
int ret = -ENOMEM;
const char *err = NULL;
__module_get(THIS_MODULE);
kobject_init(&ca->kobj, &bch_cache_ktype);
bio_init(&ca->journal.bio, NULL, ca->journal.bio.bi_inline_vecs, 8, 0);
/*
* when ca->sb.njournal_buckets is not zero, journal exists,
* and in bch_journal_replay(), tree node may split,
* so bucket of RESERVE_BTREE type is needed,
* the worst situation is all journal buckets are valid journal,
* and all the keys need to replay,
* so the number of RESERVE_BTREE type buckets should be as much
* as journal buckets
*/
btree_buckets = ca->sb.njournal_buckets ?: 8;
free = roundup_pow_of_two(ca->sb.nbuckets) >> 10;
if (!free) {
ret = -EPERM;
err = "ca->sb.nbuckets is too small";
goto err_free;
}
if (!init_fifo(&ca->free[RESERVE_BTREE], btree_buckets,
GFP_KERNEL)) {
err = "ca->free[RESERVE_BTREE] alloc failed";
goto err_btree_alloc;
}
if (!init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca),
GFP_KERNEL)) {
err = "ca->free[RESERVE_PRIO] alloc failed";
goto err_prio_alloc;
}
if (!init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL)) {
err = "ca->free[RESERVE_MOVINGGC] alloc failed";
goto err_movinggc_alloc;
}
if (!init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL)) {
err = "ca->free[RESERVE_NONE] alloc failed";
goto err_none_alloc;
}
if (!init_fifo(&ca->free_inc, free << 2, GFP_KERNEL)) {
err = "ca->free_inc alloc failed";
goto err_free_inc_alloc;
}
if (!init_heap(&ca->heap, free << 3, GFP_KERNEL)) {
err = "ca->heap alloc failed";
goto err_heap_alloc;
}
ca->buckets = vzalloc(array_size(sizeof(struct bucket),
ca->sb.nbuckets));
if (!ca->buckets) {
err = "ca->buckets alloc failed";
goto err_buckets_alloc;
}
ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
prio_buckets(ca), 2),
GFP_KERNEL);
if (!ca->prio_buckets) {
err = "ca->prio_buckets alloc failed";
goto err_prio_buckets_alloc;
}
ca->disk_buckets = alloc_meta_bucket_pages(GFP_KERNEL, &ca->sb);
if (!ca->disk_buckets) {
err = "ca->disk_buckets alloc failed";
goto err_disk_buckets_alloc;
}
ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
for_each_bucket(b, ca)
atomic_set(&b->pin, 0);
return 0;
err_disk_buckets_alloc:
kfree(ca->prio_buckets);
err_prio_buckets_alloc:
vfree(ca->buckets);
err_buckets_alloc:
free_heap(&ca->heap);
err_heap_alloc:
free_fifo(&ca->free_inc);
err_free_inc_alloc:
free_fifo(&ca->free[RESERVE_NONE]);
err_none_alloc:
free_fifo(&ca->free[RESERVE_MOVINGGC]);
err_movinggc_alloc:
free_fifo(&ca->free[RESERVE_PRIO]);
err_prio_alloc:
free_fifo(&ca->free[RESERVE_BTREE]);
err_btree_alloc:
err_free:
module_put(THIS_MODULE);
if (err)
pr_notice("error %pg: %s\n", ca->bdev, err);
return ret;
}
static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
struct file *bdev_file,
struct cache *ca)
{
const char *err = NULL; /* must be set for any error case */
int ret = 0;
memcpy(&ca->sb, sb, sizeof(struct cache_sb));
ca->bdev_file = bdev_file;
ca->bdev = file_bdev(bdev_file);
ca->sb_disk = sb_disk;
if (bdev_max_discard_sectors(file_bdev(bdev_file)))
ca->discard = CACHE_DISCARD(&ca->sb);
ret = cache_alloc(ca);
if (ret != 0) {
if (ret == -ENOMEM)
err = "cache_alloc(): -ENOMEM";
else if (ret == -EPERM)
err = "cache_alloc(): cache device is too small";
else
err = "cache_alloc(): unknown error";
pr_notice("error %pg: %s\n", file_bdev(bdev_file), err);
/*
* If we failed here, it means ca->kobj is not initialized yet,
* kobject_put() won't be called and there is no chance to
* call fput() to bdev in bch_cache_release(). So
* we explicitly call fput() on the block device here.
*/
fput(bdev_file);
return ret;
}
if (kobject_add(&ca->kobj, bdev_kobj(file_bdev(bdev_file)), "bcache")) {
pr_notice("error %pg: error calling kobject_add\n",
file_bdev(bdev_file));
ret = -ENOMEM;
goto out;
}
mutex_lock(&bch_register_lock);
err = register_cache_set(ca);
mutex_unlock(&bch_register_lock);
if (err) {
ret = -ENODEV;
goto out;
}
pr_info("registered cache device %pg\n", file_bdev(ca->bdev_file));
out:
kobject_put(&ca->kobj);
return ret;
}
/* Global interfaces/init */
static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
const char *buffer, size_t size);
static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
struct kobj_attribute *attr,
const char *buffer, size_t size);
kobj_attribute_write(register, register_bcache);
kobj_attribute_write(register_quiet, register_bcache);
kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
static bool bch_is_open_backing(dev_t dev)
{
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->bd_dev == dev)
return true;
list_for_each_entry_safe(dc, t, &uncached_devices, list)
if (dc->bdev->bd_dev == dev)
return true;
return false;
}
static bool bch_is_open_cache(dev_t dev)
{
struct cache_set *c, *tc;
list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
struct cache *ca = c->cache;
if (ca->bdev->bd_dev == dev)
return true;
}
return false;
}
static bool bch_is_open(dev_t dev)
{
return bch_is_open_cache(dev) || bch_is_open_backing(dev);
}
struct async_reg_args {
struct delayed_work reg_work;
char *path;
struct cache_sb *sb;
struct cache_sb_disk *sb_disk;
struct file *bdev_file;
void *holder;
};
static void register_bdev_worker(struct work_struct *work)
{
int fail = false;
struct async_reg_args *args =
container_of(work, struct async_reg_args, reg_work.work);
mutex_lock(&bch_register_lock);
if (register_bdev(args->sb, args->sb_disk, args->bdev_file,
args->holder) < 0)
fail = true;
mutex_unlock(&bch_register_lock);
if (fail)
pr_info("error %s: fail to register backing device\n",
args->path);
kfree(args->sb);
kfree(args->path);
kfree(args);
module_put(THIS_MODULE);
}
static void register_cache_worker(struct work_struct *work)
{
int fail = false;
struct async_reg_args *args =
container_of(work, struct async_reg_args, reg_work.work);
/* blkdev_put() will be called in bch_cache_release() */
if (register_cache(args->sb, args->sb_disk, args->bdev_file,
args->holder))
fail = true;
if (fail)
pr_info("error %s: fail to register cache device\n",
args->path);
kfree(args->sb);
kfree(args->path);
kfree(args);
module_put(THIS_MODULE);
}
static void register_device_async(struct async_reg_args *args)
{
if (SB_IS_BDEV(args->sb))
INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
else
INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
/* 10 jiffies is enough for a delay */
queue_delayed_work(system_wq, &args->reg_work, 10);
}
static void *alloc_holder_object(struct cache_sb *sb)
{
if (SB_IS_BDEV(sb))
return kzalloc(sizeof(struct cached_dev), GFP_KERNEL);
return kzalloc(sizeof(struct cache), GFP_KERNEL);
}
static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
const char *buffer, size_t size)
{
const char *err;
char *path = NULL;
struct cache_sb *sb;
struct cache_sb_disk *sb_disk;
struct file *bdev_file, *bdev_file2;
void *holder = NULL;
ssize_t ret;
bool async_registration = false;
bool quiet = false;
#ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
async_registration = true;
#endif
ret = -EBUSY;
err = "failed to reference bcache module";
if (!try_module_get(THIS_MODULE))
goto out;
/* For latest state of bcache_is_reboot */
smp_mb();
err = "bcache is in reboot";
if (bcache_is_reboot)
goto out_module_put;
ret = -ENOMEM;
err = "cannot allocate memory";
path = kstrndup(buffer, size, GFP_KERNEL);
if (!path)
goto out_module_put;
sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
if (!sb)
goto out_free_path;
ret = -EINVAL;
err = "failed to open device";
bdev_file = bdev_file_open_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
if (IS_ERR(bdev_file))
goto out_free_sb;
err = read_super(sb, file_bdev(bdev_file), &sb_disk);
if (err)
goto out_blkdev_put;
holder = alloc_holder_object(sb);
if (!holder) {
ret = -ENOMEM;
err = "cannot allocate memory";
goto out_put_sb_page;
}
/* Now reopen in exclusive mode with proper holder */
bdev_file2 = bdev_file_open_by_dev(file_bdev(bdev_file)->bd_dev,
BLK_OPEN_READ | BLK_OPEN_WRITE, holder, NULL);
fput(bdev_file);
bdev_file = bdev_file2;
if (IS_ERR(bdev_file)) {
ret = PTR_ERR(bdev_file);
bdev_file = NULL;
if (ret == -EBUSY) {
dev_t dev;
mutex_lock(&bch_register_lock);
if (lookup_bdev(strim(path), &dev) == 0 &&
bch_is_open(dev))
err = "device already registered";
else
err = "device busy";
mutex_unlock(&bch_register_lock);
if (attr == &ksysfs_register_quiet) {
quiet = true;
ret = size;
}
}
goto out_free_holder;
}
err = "failed to register device";
if (async_registration) {
/* register in asynchronous way */
struct async_reg_args *args =
kzalloc(sizeof(struct async_reg_args), GFP_KERNEL);
if (!args) {
ret = -ENOMEM;
err = "cannot allocate memory";
goto out_free_holder;
}
args->path = path;
args->sb = sb;
args->sb_disk = sb_disk;
args->bdev_file = bdev_file;
args->holder = holder;
register_device_async(args);
/* No wait and returns to user space */
goto async_done;
}
if (SB_IS_BDEV(sb)) {
mutex_lock(&bch_register_lock);
ret = register_bdev(sb, sb_disk, bdev_file, holder);
mutex_unlock(&bch_register_lock);
/* blkdev_put() will be called in cached_dev_free() */
if (ret < 0)
goto out_free_sb;
} else {
/* blkdev_put() will be called in bch_cache_release() */
ret = register_cache(sb, sb_disk, bdev_file, holder);
if (ret)
goto out_free_sb;
}
kfree(sb);
kfree(path);
module_put(THIS_MODULE);
async_done:
return size;
out_free_holder:
kfree(holder);
out_put_sb_page:
put_page(virt_to_page(sb_disk));
out_blkdev_put:
if (bdev_file)
fput(bdev_file);
out_free_sb:
kfree(sb);
out_free_path:
kfree(path);
path = NULL;
out_module_put:
module_put(THIS_MODULE);
out:
if (!quiet)
pr_info("error %s: %s\n", path?path:"", err);
return ret;
}
struct pdev {
struct list_head list;
struct cached_dev *dc;
};
static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
struct kobj_attribute *attr,
const char *buffer,
size_t size)
{
LIST_HEAD(pending_devs);
ssize_t ret = size;
struct cached_dev *dc, *tdc;
struct pdev *pdev, *tpdev;
struct cache_set *c, *tc;
mutex_lock(&bch_register_lock);
list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
if (!pdev)
break;
pdev->dc = dc;
list_add(&pdev->list, &pending_devs);
}
list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
char *pdev_set_uuid = pdev->dc->sb.set_uuid;
list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
char *set_uuid = c->set_uuid;
if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
list_del(&pdev->list);
kfree(pdev);
break;
}
}
}
mutex_unlock(&bch_register_lock);
list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
pr_info("delete pdev %p\n", pdev);
list_del(&pdev->list);
bcache_device_stop(&pdev->dc->disk);
kfree(pdev);
}
return ret;
}
static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
{
if (bcache_is_reboot)
return NOTIFY_DONE;
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 (bcache_is_reboot)
goto out;
/* New registration is rejected since now */
bcache_is_reboot = true;
/*
* Make registering caller (if there is) on other CPU
* core know bcache_is_reboot set to true earlier
*/
smp_mb();
if (list_empty(&bch_cache_sets) &&
list_empty(&uncached_devices))
goto out;
mutex_unlock(&bch_register_lock);
pr_info("Stopping all devices:\n");
/*
* The reason bch_register_lock is not held to call
* bch_cache_set_stop() and bcache_device_stop() is to
* avoid potential deadlock during reboot, because cache
* set or bcache device stopping process will acquire
* bch_register_lock too.
*
* We are safe here because bcache_is_reboot sets to
* true already, register_bcache() will reject new
* registration now. bcache_is_reboot also makes sure
* bcache_reboot() won't be re-entered on by other thread,
* so there is no race in following list iteration by
* list_for_each_entry_safe().
*/
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);
/*
* Give an early chance for other kthreads and
* kworkers to stop themselves
*/
schedule();
/* What's a condition variable? */
while (1) {
long timeout = start + 10 * HZ - jiffies;
mutex_lock(&bch_register_lock);
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);
}
finish_wait(&unregister_wait, &wait);
if (stopped)
pr_info("All devices stopped\n");
else
pr_notice("Timeout waiting for devices to be closed\n");
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_request_exit();
if (bcache_kobj)
kobject_put(bcache_kobj);
if (bcache_wq)
destroy_workqueue(bcache_wq);
if (bch_journal_wq)
destroy_workqueue(bch_journal_wq);
if (bch_flush_wq)
destroy_workqueue(bch_flush_wq);
bch_btree_exit();
if (bcache_major)
unregister_blkdev(bcache_major, "bcache");
unregister_reboot_notifier(&reboot);
mutex_destroy(&bch_register_lock);
}
/* Check and fixup module parameters */
static void check_module_parameters(void)
{
if (bch_cutoff_writeback_sync == 0)
bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC;
else if (bch_cutoff_writeback_sync > CUTOFF_WRITEBACK_SYNC_MAX) {
pr_warn("set bch_cutoff_writeback_sync (%u) to max value %u\n",
bch_cutoff_writeback_sync, CUTOFF_WRITEBACK_SYNC_MAX);
bch_cutoff_writeback_sync = CUTOFF_WRITEBACK_SYNC_MAX;
}
if (bch_cutoff_writeback == 0)
bch_cutoff_writeback = CUTOFF_WRITEBACK;
else if (bch_cutoff_writeback > CUTOFF_WRITEBACK_MAX) {
pr_warn("set bch_cutoff_writeback (%u) to max value %u\n",
bch_cutoff_writeback, CUTOFF_WRITEBACK_MAX);
bch_cutoff_writeback = CUTOFF_WRITEBACK_MAX;
}
if (bch_cutoff_writeback > bch_cutoff_writeback_sync) {
pr_warn("set bch_cutoff_writeback (%u) to %u\n",
bch_cutoff_writeback, bch_cutoff_writeback_sync);
bch_cutoff_writeback = bch_cutoff_writeback_sync;
}
}
static int __init bcache_init(void)
{
static const struct attribute *files[] = {
&ksysfs_register.attr,
&ksysfs_register_quiet.attr,
&ksysfs_pendings_cleanup.attr,
NULL
};
check_module_parameters();
mutex_init(&bch_register_lock);
init_waitqueue_head(&unregister_wait);
register_reboot_notifier(&reboot);
bcache_major = register_blkdev(0, "bcache");
if (bcache_major < 0) {
unregister_reboot_notifier(&reboot);
mutex_destroy(&bch_register_lock);
return bcache_major;
}
if (bch_btree_init())
goto err;
bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
if (!bcache_wq)
goto err;
/*
* Let's not make this `WQ_MEM_RECLAIM` for the following reasons:
*
* 1. It used `system_wq` before which also does no memory reclaim.
* 2. With `WQ_MEM_RECLAIM` desktop stalls, increased boot times, and
* reduced throughput can be observed.
*
* We still want to user our own queue to not congest the `system_wq`.
*/
bch_flush_wq = alloc_workqueue("bch_flush", 0, 0);
if (!bch_flush_wq)
goto err;
bch_journal_wq = alloc_workqueue("bch_journal", WQ_MEM_RECLAIM, 0);
if (!bch_journal_wq)
goto err;
bcache_kobj = kobject_create_and_add("bcache", fs_kobj);
if (!bcache_kobj)
goto err;
if (bch_request_init() ||
sysfs_create_files(bcache_kobj, files))
goto err;
bch_debug_init();
bcache_is_reboot = false;
return 0;
err:
bcache_exit();
return -ENOMEM;
}
/*
* Module hooks
*/
module_exit(bcache_exit);
module_init(bcache_init);
module_param(bch_cutoff_writeback, uint, 0);
MODULE_PARM_DESC(bch_cutoff_writeback, "threshold to cutoff writeback");
module_param(bch_cutoff_writeback_sync, uint, 0);
MODULE_PARM_DESC(bch_cutoff_writeback_sync, "hard threshold to cutoff writeback");
MODULE_DESCRIPTION("Bcache: a Linux block layer cache");
MODULE_AUTHOR("Kent Overstreet <[email protected]>");
MODULE_LICENSE("GPL");
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