From 2903381fce71004a7ce24d40fad53ba8236a3921 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Thu, 11 Apr 2013 15:14:35 -0700 Subject: [PATCH] bcache: Take data offset from the bdev superblock. Add a new superblock version, and consolidate related defines. Signed-off-by: Gabriel de Perthuis Signed-off-by: Kent Overstreet --- drivers/md/bcache/bcache.h | 47 +++++++++++--- drivers/md/bcache/request.c | 2 +- drivers/md/bcache/super.c | 122 ++++++++++++++++++++---------------- 3 files changed, 107 insertions(+), 64 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index f05723565f17..340146d7c17f 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -223,11 +223,17 @@ struct bkey { #define BKEY_PADDED(key) \ union { struct bkey key; uint64_t key ## _pad[BKEY_PAD]; } -/* Version 1: Backing device +/* Version 0: Cache device + * Version 1: Backing device * Version 2: Seed pointer into btree node checksum - * Version 3: New UUID format + * Version 3: Cache device with new UUID format + * Version 4: Backing device with data offset */ -#define BCACHE_SB_VERSION 3 +#define BCACHE_SB_VERSION_CDEV 0 +#define BCACHE_SB_VERSION_BDEV 1 +#define BCACHE_SB_VERSION_CDEV_WITH_UUID 3 +#define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4 +#define BCACHE_SB_MAX_VERSION 4 #define SB_SECTOR 8 #define SB_SIZE 4096 @@ -236,13 +242,12 @@ struct bkey { /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */ #define MAX_CACHES_PER_SET 8 -#define BDEV_DATA_START 16 /* sectors */ +#define BDEV_DATA_START_DEFAULT 16 /* sectors */ struct cache_sb { uint64_t csum; uint64_t offset; /* sector where this sb was written */ uint64_t version; -#define CACHE_BACKING_DEV 1 uint8_t magic[16]; @@ -257,12 +262,28 @@ struct cache_sb { uint64_t seq; uint64_t pad[8]; - uint64_t nbuckets; /* device size */ - uint16_t block_size; /* sectors */ - uint16_t bucket_size; /* sectors */ + union { + struct { + /* Cache devices */ + uint64_t nbuckets; /* device size */ - uint16_t nr_in_set; - uint16_t nr_this_dev; + uint16_t block_size; /* sectors */ + uint16_t bucket_size; /* sectors */ + + uint16_t nr_in_set; + uint16_t nr_this_dev; + }; + struct { + /* Backing devices */ + uint64_t data_offset; + + /* + * block_size from the cache device section is still used by + * backing devices, so don't add anything here until we fix + * things to not need it for backing devices anymore + */ + }; + }; uint32_t last_mount; /* time_t */ @@ -861,6 +882,12 @@ static inline bool key_merging_disabled(struct cache_set *c) #endif } +static inline bool SB_IS_BDEV(const struct cache_sb *sb) +{ + return sb->version == BCACHE_SB_VERSION_BDEV + || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET; +} + struct bbio { unsigned submit_time_us; union { diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index 83731dc36f34..e5ff12e52d5b 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -1220,7 +1220,7 @@ static void cached_dev_make_request(struct request_queue *q, struct bio *bio) part_stat_unlock(); bio->bi_bdev = dc->bdev; - bio->bi_sector += BDEV_DATA_START; + bio->bi_sector += dc->sb.data_offset; if (cached_dev_get(dc)) { s = search_alloc(bio, d); diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 5fa3cd2d9ff0..f1e69f2fad37 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -110,15 +110,7 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, sb->flags = le64_to_cpu(s->flags); sb->seq = le64_to_cpu(s->seq); - - sb->nbuckets = le64_to_cpu(s->nbuckets); - sb->block_size = le16_to_cpu(s->block_size); - sb->bucket_size = le16_to_cpu(s->bucket_size); - - sb->nr_in_set = le16_to_cpu(s->nr_in_set); - sb->nr_this_dev = le16_to_cpu(s->nr_this_dev); 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); @@ -147,53 +139,77 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, if (bch_is_zero(sb->uuid, 16)) goto err; - err = "Unsupported superblock version"; - if (sb->version > BCACHE_SB_VERSION) - goto err; + switch (sb->version) { + case BCACHE_SB_VERSION_BDEV: + sb->block_size = le16_to_cpu(s->block_size); + sb->data_offset = BDEV_DATA_START_DEFAULT; + break; + case BCACHE_SB_VERSION_BDEV_WITH_OFFSET: + sb->block_size = le16_to_cpu(s->block_size); + sb->data_offset = le64_to_cpu(s->data_offset); - 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 = "Too many buckets"; - if (sb->nbuckets > LONG_MAX) - goto err; - - err = "Not enough buckets"; - if (sb->nbuckets < 1 << 7) - goto err; - - err = "Invalid superblock: device too small"; - if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets) - goto err; - - if (sb->version == CACHE_BACKING_DEV) - goto out; - - 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) + err = "Bad data offset"; + if (sb->data_offset < BDEV_DATA_START_DEFAULT) goto err; - err = "Too many journal buckets"; - if (sb->first_bucket + sb->keys > sb->nbuckets) - goto err; + break; + case BCACHE_SB_VERSION_CDEV: + case BCACHE_SB_VERSION_CDEV_WITH_UUID: + sb->nbuckets = le64_to_cpu(s->nbuckets); + sb->block_size = le16_to_cpu(s->block_size); + sb->bucket_size = le16_to_cpu(s->bucket_size); - err = "Invalid superblock: first bucket comes before end of super"; - if (sb->first_bucket * sb->bucket_size < 16) + 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; -out: + } + sb->last_mount = get_seconds(); err = NULL; @@ -286,7 +302,7 @@ void bcache_write_super(struct cache_set *c) for_each_cache(ca, c, i) { struct bio *bio = &ca->sb_bio; - ca->sb.version = BCACHE_SB_VERSION; + ca->sb.version = BCACHE_SB_VERSION_CDEV_WITH_UUID; ca->sb.seq = c->sb.seq; ca->sb.last_mount = c->sb.last_mount; @@ -1049,7 +1065,7 @@ static const char *register_bdev(struct cache_sb *sb, struct page *sb_page, g = dc->disk.disk; - set_capacity(g, dc->bdev->bd_part->nr_sects - 16); + set_capacity(g, dc->bdev->bd_part->nr_sects - dc->sb.data_offset); bch_cached_dev_request_init(dc); @@ -1802,7 +1818,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, if (err) goto err_close; - if (sb->version == CACHE_BACKING_DEV) { + if (SB_IS_BDEV(sb)) { struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL); err = register_bdev(sb, sb_page, bdev, dc);