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// 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 <kent.overstreet@gmail.com>
* Copyright 2012 Google, Inc.
*/
#include "bcache.h"
#include "btree.h"
#include "debug.h"
#include "extents.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/idr.h>
#include <linux/kthread.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_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 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 int 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 (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 = "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->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 = (u32)ktime_get_real_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)
{
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 bio *bio)
{
struct cache_sb *out = page_address(bio_first_page_all(bio));
unsigned int i;
bio->bi_iter.bi_sector = SB_SECTOR;
bio->bi_iter.bi_size = SB_SIZE;
bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC|REQ_META);
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(bio);
}
static void bch_write_bdev_super_unlock(struct closure *cl)
{
struct cached_dev *dc = container_of(cl, 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_reset(bio);
bio_set_dev(bio, dc->bdev);
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, 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 void bcache_write_super_unlock(struct closure *cl)
{
struct cache_set *c = container_of(cl, 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;
unsigned int i;
down(&c->sb_write_mutex);
closure_init(cl, &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_set_dev(bio, ca->bdev);
bio->bi_end_io = write_super_endio;
bio->bi_private = ca;
closure_get(cl);
__write_super(&ca->sb, 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 void uuid_io_unlock(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, uuid_write);
up(&c->uuid_write_mutex);
}
static void uuid_io(struct cache_set *c, int op, unsigned long op_flags,
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 = REQ_SYNC | REQ_META | op_flags;
bio->bi_iter.bi_size = KEY_SIZE(k) << 9;
bio->bi_end_io = uuid_endio;
bio->bi_private = cl;
bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
bch_bio_map(bio, c->uuids);
bch_submit_bbio(bio, c, k, i);
if (op != REQ_OP_WRITE)
break;
}
bch_extent_to_text(buf, sizeof(buf), k);
pr_debug("%s UUIDs at %s", op == 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",
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, 0, 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;
closure_init_stack(&cl);
lockdep_assert_held(&bch_register_lock);
if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
return 1;
SET_KEY_SIZE(&k.key, c->sb.bucket_size);
uuid_io(c, REQ_OP_WRITE, 0, &k.key, &cl);
closure_sync(&cl);
/* Only one bucket used for uuid write */
ca = PTR_CACHE(c, &k.key, 0);
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, int op,
unsigned long op_flags)
{
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 = bucket_bytes(ca);
bio->bi_end_io = prio_endio;
bio->bi_private = ca;
bio_set_op_attrs(bio, op, REQ_SYNC|REQ_META|op_flags);
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",
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, bucket_bytes(ca) - 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, 0);
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 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 int 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, REQ_OP_READ, 0);
if (p->csum !=
bch_crc64(&p->magic, bucket_bytes(ca) - 8))
pr_warn("bad csum reading priorities");
if (p->magic != pset_magic(&ca->sb))
pr_warn("bad magic reading priorities");
bucket = p->next_bucket;
d = p->data;
}
b->prio = le16_to_cpu(d->prio);
b->gen = b->last_gc = 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 (test_bit(BCACHE_DEV_CLOSING, &d->flags))
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 (!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)) {
unsigned int 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 int i;
struct cache *ca;
int ret;
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);
ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
if (ret < 0)
pr_err("Couldn't create device -> cache set symlink");
ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
if (ret < 0)
pr_err("Couldn't create cache set -> device symlink");
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", disk->disk_name);
else
pr_err("bcache device (NULL gendisk) stopped");
if (d->c)
bcache_device_detach(d);
if (disk) {
if (disk->flags & GENHD_FL_UP)
del_gendisk(disk);
if (disk->queue)
blk_cleanup_queue(disk->queue);
ida_simple_remove(&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 request_queue *q;
const size_t max_stripes = min_t(size_t, INT_MAX,
SIZE_MAX / sizeof(atomic_t));
size_t n;
int idx;
if (!d->stripe_size)
d->stripe_size = 1 << 31;
d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
if (!d->nr_stripes || d->nr_stripes > max_stripes) {
pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)",
(unsigned int)d->nr_stripes);
return -ENOMEM;
}
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)
return -ENOMEM;
idx = ida_simple_get(&bcache_device_idx, 0,
BCACHE_DEVICE_IDX_MAX, GFP_KERNEL);
if (idx < 0)
return idx;
if (bioset_init(&d->bio_split, 4, offsetof(struct bbio, bio),
BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
goto err;
d->disk = alloc_disk(BCACHE_MINORS);
if (!d->disk)
goto err;
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->fops = &bcache_ops;
d->disk->private_data = d;
q = blk_alloc_queue(GFP_KERNEL);
if (!q)
return -ENOMEM;
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;
blk_queue_max_discard_sectors(q, UINT_MAX);
q->limits.discard_granularity = 512;
q->limits.io_min = block_size;
q->limits.logical_block_size = block_size;
q->limits.physical_block_size = block_size;
blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
blk_queue_flag_set(QUEUE_FLAG_DISCARD, d->disk->queue);
blk_queue_write_cache(q, true, true);
return 0;
err:
ida_simple_remove(&bcache_device_idx, idx);
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_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("%s: device offline for %d seconds",
dc->backing_dev_name,
BACKING_DEV_OFFLINE_TIMEOUT);
pr_err("%s: disable I/O request due to backing "
"device offline", 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)
{
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 %s",
dc->backing_dev_name);
kfree(env[1]);
kfree(env[2]);
kfree(buf);
return -EIO;
}
if (atomic_xchg(&dc->running, 1)) {
kfree(env[1]);
kfree(env[2]);
kfree(buf);
pr_info("cached dev %s is running already",
dc->backing_dev_name);
return -EBUSY;
}
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]);
kfree(buf);
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");
return -ENOMEM;
}
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");
}
return 0;
}
/*
* 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");
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 closure cl;
closure_init_stack(&cl);
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;
}
memset(&dc->sb.set_uuid, 0, 16);
SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
bch_write_bdev_super(dc, &cl);
closure_sync(&cl);
mutex_lock(&bch_register_lock);
calc_cached_dev_sectors(dc->disk.c);
bcache_device_detach(&dc->disk);
list_move(&dc->list, &uncached_devices);
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 %s", dc->backing_dev_name);
/* 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->sb.set_uuid, 16)) ||
(!set_uuid && memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16)))
return -ENOENT;
if (dc->disk.c) {
pr_err("Can't attach %s: already attached",
dc->backing_dev_name);
return -EINVAL;
}
if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
pr_err("Can't attach %s: shutting down",
dc->backing_dev_name);
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",
dc->backing_dev_name);
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 %s but duplicate UUID already attached",
dc->backing_dev_name);
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 %s in set",
dc->backing_dev_name);
return -ENOENT;
}
u = uuid_find_empty(c);
if (!u) {
pr_err("Not caching %s, no room for UUID",
dc->backing_dev_name);
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);
/*
* 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",
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 %s",
dc->backing_dev_name);
return ret;
}
bcache_device_link(&dc->disk, c, "bdev");
atomic_inc(&c->attached_dev_nr);
/* Allow the writeback thread to proceed */
up_write(&dc->writeback_lock);
pr_info("Caching %s as %s on set %pU",
dc->backing_dev_name,
dc->disk.disk->disk_name,
dc->disk.c->sb.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 void cached_dev_free(struct closure *cl)
{
struct cached_dev *dc = container_of(cl, 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);
bcache_device_free(&dc->disk);
list_del(&dc->list);
mutex_unlock(&bch_register_lock);
if (!IS_ERR_OR_NULL(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);
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);
}
dc->disk.stripe_size = q->limits.io_opt >> 9;
if (dc->disk.stripe_size)
dc->partial_stripes_expensive =
q->limits.raid_partial_stripes_expensive;
ret = bcache_device_init(&dc->disk, block_size,
dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
if (ret)
return ret;
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);
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 page *sb_page,
struct block_device *bdev,
struct cached_dev *dc)
{
const char *err = "cannot allocate memory";
struct cache_set *c;
int ret = -ENOMEM;
bdevname(bdev, dc->backing_dev_name);
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_inline_vecs, 1);
bio_first_bvec_all(&dc->sb_bio)->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", dc->backing_dev_name);
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 %s: %s", dc->backing_dev_name, 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 void flash_dev_free(struct closure *cl)
{
struct bcache_device *d = container_of(cl, struct bcache_device, cl);
mutex_lock(&bch_register_lock);
atomic_long_sub(bcache_dev_sectors_dirty(d),
&d->c->flash_dev_dirty_sectors);
bcache_device_free(d);
mutex_unlock(&bch_register_lock);
kobject_put(&d->kobj);
}
static void flash_dev_flush(struct closure *cl)
{
struct bcache_device *d = container_of(cl, 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)
{
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_sectors_dirty_init(d);
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;
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");
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 %s\n",
dc->disk.disk->disk_name, dc->backing_dev_name);
bcache_device_stop(&dc->disk);
return true;
}
/* Cache set */
__printf(2, 3)
bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
{
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");
/*
* XXX: we can be called from atomic context
* acquire_console_sem();
*/
pr_err("bcache: error on %pU: ", c->sb.set_uuid);
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
pr_err(", disabling caching\n");
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 void cache_set_free(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, cl);
struct cache *ca;
unsigned int i;
debugfs_remove(c->debug);
bch_open_buckets_free(c);
bch_btree_cache_free(c);
bch_journal_free(c);
mutex_lock(&bch_register_lock);
for_each_cache(ca, c, i)
if (ca) {
ca->set = NULL;
c->cache[ca->sb.nr_this_dev] = NULL;
kobject_put(&ca->kobj);
}
bch_bset_sort_state_free(&c->sort);
free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
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", 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 int i;
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_OR_NULL(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);
}
for_each_cache(ca, c, i)
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.",
d->disk->disk_name, c->sb.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.",
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.",
d->disk->disk_name);
}
}
static void __cache_set_unregister(struct closure *cl)
{
struct cache_set *c = container_of(cl, 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_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->devices_max_used = 0;
atomic_set(&c->attached_dev_nr, 0);
c->btree_pages = bucket_pages(c);
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 = (sb->bucket_size / sb->block_size + 1) *
sizeof(struct btree_iter_set);
if (!(c->devices = kcalloc(c->nr_uuids, sizeof(void *), GFP_KERNEL)) ||
mempool_init_slab_pool(&c->search, 32, bch_search_cache) ||
mempool_init_kmalloc_pool(&c->bio_meta, 2,
sizeof(struct bbio) + sizeof(struct bio_vec) *
bucket_pages(c)) ||
mempool_init_kmalloc_pool(&c->fill_iter, 1, iter_size) ||
bioset_init(&c->bio_split, 4, offsetof(struct bbio, bio),
BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER) ||
!(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
!(c->moving_gc_wq = alloc_workqueue("bcache_gc",
WQ_MEM_RECLAIM, 0)) ||
bch_journal_alloc(c) ||
bch_btree_cache_alloc(c) ||
bch_open_buckets_alloc(c) ||
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;
struct closure cl;
unsigned int i;
LIST_HEAD(journal);
struct journal_replay *l;
closure_init_stack(&cl);
for_each_cache(ca, c, i)
c->nbuckets += ca->sb.nbuckets;
set_gc_sectors(c);
if (CACHE_SYNC(&c->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");
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_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_OR_NULL(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_btree_check() may occupy too much system memory which
* has negative effects to user space application (e.g. data
* base) performance. Shrink the mca cache memory proactively
* here to avoid competing memory with user space workloads..
*/
if (!c->shrinker_disabled) {
struct shrink_control sc;
sc.gfp_mask = GFP_KERNEL;
sc.nr_to_scan = c->btree_cache_used * c->btree_pages;
/* first run to clear b->accessed tag */
c->shrink.scan_objects(&c->shrink, &sc);
/* second run to reap non-accessed nodes */
c->shrink.scan_objects(&c->shrink, &sc);
}
bch_journal_mark(c, &journal);
bch_initial_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);
err = "bcache: replay journal failed";
if (bch_journal_replay(c, &journal))
goto err;
} else {
pr_notice("invalidating existing data");
for_each_cache(ca, c, i) {
unsigned int 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_initial_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, 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_OR_NULL(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->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->sb.last_mount = (u32)ktime_get_real_seconds();
bcache_write_super(c);
list_for_each_entry_safe(dc, t, &uncached_devices, list)
bch_cached_dev_attach(dc, c, NULL);
flash_devs_run(c);
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 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.bucket_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);
}
kobject_get(&ca->kobj);
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) {
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->sb.nr_this_dev] != ca);
ca->set->cache[ca->sb.nr_this_dev] = NULL;
}
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->free_inc);
for (i = 0; i < RESERVE_NR; i++)
free_fifo(&ca->free[i]);
if (ca->sb_bio.bi_inline_vecs[0].bv_page)
put_page(bio_first_page_all(&ca->sb_bio));
if (!IS_ERR_OR_NULL(ca->bdev))
blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
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, ca->journal.bio.bi_inline_vecs, 8);
/*
* 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_bucket_pages(GFP_KERNEL, ca);
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 %s: %s", ca->cache_dev_name, err);
return ret;
}
static int register_cache(struct cache_sb *sb, struct page *sb_page,
struct block_device *bdev, struct cache *ca)
{
const char *err = NULL; /* must be set for any error case */
int ret = 0;
bdevname(bdev, ca->cache_dev_name);
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_inline_vecs, 1);
bio_first_bvec_all(&ca->sb_bio)->bv_page = sb_page;
get_page(sb_page);
if (blk_queue_discard(bdev_get_queue(bdev)))
ca->discard = CACHE_DISCARD(&ca->sb);
ret = cache_alloc(ca);
if (ret != 0) {
/*
* 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 blkdev_put() to bdev in bch_cache_release(). So we
* explicitly call blkdev_put() here.
*/
blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
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";
goto err;
}
if (kobject_add(&ca->kobj,
&part_to_dev(bdev->bd_part)->kobj,
"bcache")) {
err = "error calling kobject_add";
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 %s", ca->cache_dev_name);
out:
kobject_put(&ca->kobj);
err:
if (err)
pr_notice("error %s: %s", ca->cache_dev_name, err);
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(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 int 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 = -EINVAL;
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;
/* For latest state of bcache_is_reboot */
smp_mb();
if (bcache_is_reboot)
return -EBUSY;
path = kstrndup(buffer, size, GFP_KERNEL);
if (!path)
goto err;
sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL);
if (!sb)
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));
mutex_lock(&bch_register_lock);
if (!IS_ERR(bdev) && bch_is_open(bdev))
err = "device already registered";
else
err = "device busy";
mutex_unlock(&bch_register_lock);
if (!IS_ERR(bdev))
bdput(bdev);
if (attr == &ksysfs_register_quiet)
goto quiet_out;
}
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;
err = "failed to register device";
if (SB_IS_BDEV(sb)) {
struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
if (!dc)
goto err_close;
mutex_lock(&bch_register_lock);
ret = register_bdev(sb, sb_page, bdev, dc);
mutex_unlock(&bch_register_lock);
/* blkdev_put() will be called in cached_dev_free() */
if (ret < 0)
goto err;
} else {
struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
if (!ca)
goto err_close;
/* blkdev_put() will be called in bch_cache_release() */
if (register_cache(sb, sb_page, bdev, ca) != 0)
goto err;
}
quiet_out:
ret = size;
out:
if (sb_page)
put_page(sb_page);
kfree(sb);
kfree(path);
module_put(THIS_MODULE);
return ret;
err_close:
blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
err:
pr_info("error %s: %s", path, err);
goto out;
}
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) {
list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
char *pdev_set_uuid = pdev->dc->sb.set_uuid;
char *set_uuid = c->sb.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", 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:");
/*
* 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 acqurie
* 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");
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_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 (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",
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",
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",
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;
}
bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
if (!bcache_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();
closure_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 <kent.overstreet@gmail.com>");
MODULE_LICENSE("GPL");
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