Commit 5b21403c authored by Coly Li's avatar Coly Li Committed by Jens Axboe
Browse files

bcache: add read_super_common() to read major part of super block 



Later patches will introduce feature set bits to on-disk super block and
increase super block version. Current code in read_super() which reads
common part of super block for version BCACHE_SB_VERSION_CDEV and version
BCACHE_SB_VERSION_CDEV_WITH_UUID will be shared with the new version.

Therefore this patch moves the reusable part into read_super_common(),
this preparation patch will make later patches more simplier and only
focus on new feature set bits.

Signed-off-by: default avatarColy Li <colyli@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7a148126

drivers/md/bcache/super.c

+63 −48
Original line number Diff line number Diff line
@@ -59,6 +59,67 @@ struct workqueue_struct *bch_journal_wq; 


/* Superblock */



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->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;



	err = NULL;

err:

	return err;

}





static const char *read_super(struct cache_sb *sb, struct block_device *bdev,

			      struct cache_sb_disk **res)

{
@@ -133,55 +194,9 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 
		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)

		err = read_super_common(sb, bdev, s);

		if (err)

			goto err;



		break;

	default:

		err = "Unsupported superblock version";

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