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-rw-r--r--drivers/md/bcache/super.c2941
1 files changed, 2941 insertions, 0 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
new file mode 100644
index 000000000..70e5bd896
--- /dev/null
+++ b/drivers/md/bcache/super.c
@@ -0,0 +1,2941 @@
+// 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 "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_inode->i_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 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_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 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 = 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 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, 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 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_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_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 block_device *cached_bdev,
+ const struct block_device_operations *ops)
+{
+ struct request_queue *q;
+ const size_t max_stripes = min_t(size_t, INT_MAX,
+ SIZE_MAX / sizeof(atomic_t));
+ uint64_t n;
+ int idx;
+
+ 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_simple_get(&bcache_device_idx, 0,
+ BCACHE_DEVICE_IDX_MAX, 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;
+
+ d->disk = blk_alloc_disk(NUMA_NO_NODE);
+ if (!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;
+
+ q = d->disk->queue;
+ 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_VECS;
+ 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;
+
+ if (q->limits.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("%s: sb/logical block size (%u) greater than page size (%lu) falling back to device logical block size (%u)\n",
+ d->disk->disk_name, q->limits.logical_block_size,
+ PAGE_SIZE, bdev_logical_block_size(cached_bdev));
+
+ /* This also adjusts physical block size/min io size if needed */
+ blk_queue_logical_block_size(q, bdev_logical_block_size(cached_bdev));
+ }
+
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, d->disk->queue);
+ blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, d->disk->queue);
+
+ blk_queue_write_cache(q, true, true);
+
+ return 0;
+
+out_bioset_exit:
+ bioset_exit(&d->bio_split);
+out_ida_remove:
+ ida_simple_remove(&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 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);
+ 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 (!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,
+ bdev_nr_sectors(dc->bdev) - dc->sb.data_offset,
+ dc->bdev, &bcache_cached_ops);
+ if (ret)
+ return ret;
+
+ blk_queue_io_opt(dc->disk.disk->queue,
+ max(queue_io_opt(dc->disk.disk->queue), queue_io_opt(q)));
+
+ 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 block_device *bdev,
+ 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 = bdev;
+ dc->bdev->bd_holder = dc;
+ 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(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 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);
+ del_gendisk(d->disk);
+ 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)
+{
+ 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 void cache_set_free(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, 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 void cache_set_flush(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, 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 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_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 + 1) *
+ 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 (!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, 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 block_device *bdev, 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 = bdev;
+ ca->bdev->bd_holder = ca;
+ ca->sb_disk = sb_disk;
+
+ if (bdev_max_discard_sectors((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, bdev_kobj(bdev), "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 %pg\n", ca->bdev);
+
+out:
+ kobject_put(&ca->kobj);
+
+err:
+ if (err)
+ pr_notice("error %pg: %s\n", ca->bdev, 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(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 block_device *bdev;
+};
+
+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);
+ struct cached_dev *dc;
+
+ dc = kzalloc(sizeof(*dc), GFP_KERNEL);
+ if (!dc) {
+ fail = true;
+ put_page(virt_to_page(args->sb_disk));
+ blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+ goto out;
+ }
+
+ mutex_lock(&bch_register_lock);
+ if (register_bdev(args->sb, args->sb_disk, args->bdev, dc) < 0)
+ fail = true;
+ mutex_unlock(&bch_register_lock);
+
+out:
+ 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);
+ struct cache *ca;
+
+ ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+ if (!ca) {
+ fail = true;
+ put_page(virt_to_page(args->sb_disk));
+ blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+ goto out;
+ }
+
+ /* blkdev_put() will be called in bch_cache_release() */
+ if (register_cache(args->sb, args->sb_disk, args->bdev, ca) != 0)
+ fail = true;
+
+out:
+ 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 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 block_device *bdev;
+ ssize_t ret;
+ bool async_registration = 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 = blkdev_get_by_path(strim(path),
+ FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+ sb);
+ if (IS_ERR(bdev)) {
+ if (bdev == ERR_PTR(-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)
+ goto done;
+ }
+ goto out_free_sb;
+ }
+
+ err = "failed to set blocksize";
+ if (set_blocksize(bdev, 4096))
+ goto out_blkdev_put;
+
+ err = read_super(sb, bdev, &sb_disk);
+ if (err)
+ goto out_blkdev_put;
+
+ 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_put_sb_page;
+ }
+
+ args->path = path;
+ args->sb = sb;
+ args->sb_disk = sb_disk;
+ args->bdev = bdev;
+ register_device_async(args);
+ /* No wait and returns to user space */
+ goto async_done;
+ }
+
+ if (SB_IS_BDEV(sb)) {
+ struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
+
+ if (!dc) {
+ ret = -ENOMEM;
+ err = "cannot allocate memory";
+ goto out_put_sb_page;
+ }
+
+ mutex_lock(&bch_register_lock);
+ ret = register_bdev(sb, sb_disk, bdev, dc);
+ mutex_unlock(&bch_register_lock);
+ /* blkdev_put() will be called in cached_dev_free() */
+ if (ret < 0)
+ goto out_free_sb;
+ } else {
+ struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+
+ if (!ca) {
+ ret = -ENOMEM;
+ err = "cannot allocate memory";
+ goto out_put_sb_page;
+ }
+
+ /* blkdev_put() will be called in bch_cache_release() */
+ ret = register_cache(sb, sb_disk, bdev, ca);
+ if (ret)
+ goto out_free_sb;
+ }
+
+done:
+ kfree(sb);
+ kfree(path);
+ module_put(THIS_MODULE);
+async_done:
+ return size;
+
+out_put_sb_page:
+ put_page(virt_to_page(sb_disk));
+out_blkdev_put:
+ blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+out_free_sb:
+ kfree(sb);
+out_free_path:
+ kfree(path);
+ path = NULL;
+out_module_put:
+ module_put(THIS_MODULE);
+out:
+ 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();
+ 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");