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jbd2: switch to using the crc32c library

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Now that the crc32c() library function directly takes advantage of
architecture-specific optimizations, it is unnecessary to go through the
crypto API.  Just use crc32c().  This is much simpler, and it improves
performance due to eliminating the crypto API overhead.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20241202010844.144356-18-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2024-12-01 17:08:42 -08:00
parent f2b4fa1964
commit dd348f054b
3 changed files with 6 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/jbd2/Kconfig
View File

@ -2,8 +2,6 @@
config JBD2
tristate
select CRC32
select CRYPTO
select CRYPTO_CRC32C
help
This is a generic journaling layer for block devices that support
both 32-bit and 64-bit block numbers. It is currently used by

30
fs/jbd2/journal.c
View File

@ -1369,20 +1369,12 @@ static int journal_check_superblock(journal_t *journal)
return err;
}
/* Load the checksum driver */
if (jbd2_journal_has_csum_v2or3_feature(journal)) {
if (sb->s_checksum_type != JBD2_CRC32C_CHKSUM) {
printk(KERN_ERR "JBD2: Unknown checksum type\n");
return err;
}
journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
err = PTR_ERR(journal->j_chksum_driver);
journal->j_chksum_driver = NULL;
return err;
}
/* Check superblock checksum */
if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
printk(KERN_ERR "JBD2: journal checksum error\n");
@ -1608,8 +1600,6 @@ static journal_t *journal_init_common(struct block_device *bdev,
err_cleanup:
percpu_counter_destroy(&journal->j_checkpoint_jh_count);
if (journal->j_chksum_driver)
crypto_free_shash(journal->j_chksum_driver);
kfree(journal->j_wbuf);
jbd2_journal_destroy_revoke(journal);
journal_fail_superblock(journal);
@ -2191,8 +2181,6 @@ int jbd2_journal_destroy(journal_t *journal)
iput(journal->j_inode);
if (journal->j_revoke)
jbd2_journal_destroy_revoke(journal);
if (journal->j_chksum_driver)
crypto_free_shash(journal->j_chksum_driver);
kfree(journal->j_fc_wbuf);
kfree(journal->j_wbuf);
kfree(journal);
@ -2337,27 +2325,15 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
}
}
/* Load the checksum driver if necessary */
if ((journal->j_chksum_driver == NULL) &&
INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
journal->j_chksum_driver = NULL;
return 0;
}
/* Precompute checksum seed for all metadata */
journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
sizeof(sb->s_uuid));
}
lock_buffer(journal->j_sb_buffer);
/* If enabling v3 checksums, update superblock */
/* If enabling v3 checksums, update superblock and precompute seed */
if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
sb->s_feature_compat &=
~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
sizeof(sb->s_uuid));
}
/* If enabling v1 checksums, downgrade superblock */

33
include/linux/jbd2.h
View File

@ -28,7 +28,7 @@
#include <linux/slab.h>
#include <linux/bit_spinlock.h>
#include <linux/blkdev.h>
#include <crypto/hash.h>
#include <linux/crc32c.h>
#endif
#define journal_oom_retry 1
@ -1241,13 +1241,6 @@ struct journal_s
*/
void *j_private;
/**
* @j_chksum_driver:
*
* Reference to checksum algorithm driver via cryptoapi.
*/
struct crypto_shash *j_chksum_driver;
/**
* @j_csum_seed:
*
@ -1750,10 +1743,7 @@ static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)
static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
{
WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&
journal->j_chksum_driver == NULL);
return journal->j_chksum_driver != NULL;
return jbd2_journal_has_csum_v2or3_feature(journal);
}
static inline int jbd2_journal_get_num_fc_blks(journal_superblock_t *jsb)
@ -1790,27 +1780,10 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal)
#define BJ_Reserved 4 /* Buffer is reserved for access by journal */
#define BJ_Types 5
/* JBD uses a CRC32 checksum */
#define JBD_MAX_CHECKSUM_SIZE 4
static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
const void *address, unsigned int length)
{
DEFINE_RAW_FLEX(struct shash_desc, desc, __ctx,
DIV_ROUND_UP(JBD_MAX_CHECKSUM_SIZE,
sizeof(*((struct shash_desc *)0)->__ctx)));
int err;
BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) >
JBD_MAX_CHECKSUM_SIZE);
desc->tfm = journal->j_chksum_driver;
*(u32 *)desc->__ctx = crc;
err = crypto_shash_update(desc, address, length);
BUG_ON(err);
return *(u32 *)desc->__ctx;
return crc32c(crc, address, length);
}
/* Return most recent uncommitted transaction */