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Commit 2903381f authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcache: Take data offset from the bdev superblock. 



Add a new superblock version, and consolidate related defines.

Signed-off-by: default avatarGabriel de Perthuis <g2p.code+bcache@gmail.com>
Signed-off-by: default avatarKent Overstreet <koverstreet@google.com>
parent cef52797

drivers/md/bcache/bcache.h

+37 −10
Original line number Diff line number Diff line
@@ -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];



	union {

	struct {

		/* Cache devices */

		uint64_t	nbuckets;	/* device size */



		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 {

drivers/md/bcache/request.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/md/bcache/super.c

+62 −46
Original line number Diff line number Diff line
@@ -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);
@@ -147,15 +139,29 @@ 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)

		err = "Bad data offset";

		if (sb->data_offset < BDEV_DATA_START_DEFAULT)

			goto err;



		break;

	case BCACHE_SB_VERSION_CDEV:

	case BCACHE_SB_VERSION_CDEV_WITH_UUID:

		sb->nbuckets	= le64_to_cpu(s->nbuckets);

		sb->block_size	= le16_to_cpu(s->block_size);

		sb->bucket_size	= le16_to_cpu(s->bucket_size);



		sb->nr_in_set	= le16_to_cpu(s->nr_in_set);

		sb->nr_this_dev	= le16_to_cpu(s->nr_this_dev);



		err = "Too many buckets";

		if (sb->nbuckets > LONG_MAX)

			goto err;
@@ -164,13 +170,17 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 
		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;



	if (sb->version == CACHE_BACKING_DEV)

		goto out;



		err = "Bad UUID";

		if (bch_is_zero(sb->set_uuid, 16))

			goto err;
@@ -193,7 +203,13 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 
		err = "Invalid superblock: first bucket comes before end of super";

		if (sb->first_bucket * sb->bucket_size < 16)

			goto err;

out:



		break;

	default:

		err = "Unsupported superblock version";

		goto err;

	}



	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);