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: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2019-10-08 18:41:33 +02:00
parent 41e6d2a808
commit b4e967be43
3 changed files with 16 additions and 3 deletions

View File

@ -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);

View File

@ -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);

View File

@ -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);
}