Commit b4e967be authored by David Sterba's avatar David Sterba
Browse files

btrfs: add member for a specific checksum driver 



Currently all the checksum algorithms generate a fixed size digest size
and we use it.  The on-disk format can hold up to BTRFS_CSUM_SIZE bytes
and BLAKE2b produces digest of 512 bits by default. We can't do that and
will use the blake2b-256, this needs to be passed to the crypto API.

Separate that from the base algorithm name and add a member to request
specific driver, in this case with the digest size.

The only place that uses the driver name is the crypto API setup.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 41e6d2a8

fs/btrfs/ctree.c

+12 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ static void del_ptr(struct btrfs_root *root, struct btrfs_path *path, 
static const struct btrfs_csums {

	u16		size;

	const char	*name;

	const char	*driver;

} btrfs_csums[] = {

	[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },

	[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
@@ -53,6 +54,17 @@ const char *btrfs_super_csum_name(u16 csum_type) 
	return btrfs_csums[csum_type].name;

}



/*

 * Return driver name if defined, otherwise the name that's also a valid driver

 * name

 */

const char *btrfs_super_csum_driver(u16 csum_type)

{

	/* csum type is validated at mount time */

	return btrfs_csums[csum_type].driver ?:

		btrfs_csums[csum_type].name;

}



size_t __const btrfs_get_num_csums(void)

{

	return ARRAY_SIZE(btrfs_csums);

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -2163,6 +2163,7 @@ BTRFS_SETGET_STACK_FUNCS(super_uuid_tree_generation, struct btrfs_super_block, 


int btrfs_super_csum_size(const struct btrfs_super_block *s);

const char *btrfs_super_csum_name(u16 csum_type);

const char *btrfs_super_csum_driver(u16 csum_type);

size_t __const btrfs_get_num_csums(void);

fs/btrfs/disk-io.c

+3 −3
Original line number Diff line number Diff line
@@ -2219,13 +2219,13 @@ static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info, 
static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info, u16 csum_type)

{

	struct crypto_shash *csum_shash;

	const char *csum_name = btrfs_super_csum_name(csum_type);

	const char *csum_driver = btrfs_super_csum_driver(csum_type);



	csum_shash = crypto_alloc_shash(csum_name, 0, 0);

	csum_shash = crypto_alloc_shash(csum_driver, 0, 0);



	if (IS_ERR(csum_shash)) {

		btrfs_err(fs_info, "error allocating %s hash for checksum",

			  csum_name);

			  csum_driver);

		return PTR_ERR(csum_shash);

	}

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