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jbd2: Grab a reference to the crc32c driver if necessary

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Obtain a reference to the crc32c driver if needed for the v2 checksum.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2012-05-27 07:50:56 -04:00 committed by Theodore Ts'o
parent 25ed6e8a54
commit 01b5adcebb
3 changed files with 50 additions and 0 deletions
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2
fs/jbd2/Kconfig
View file

@ -1,6 +1,8 @@
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

25
fs/jbd2/journal.c
View file

@ -1438,6 +1438,17 @@ static int journal_get_superblock(journal_t *journal)
goto out;
}
/* Load the checksum driver */
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD: Cannot load crc32c driver.\n");
err = PTR_ERR(journal->j_chksum_driver);
journal->j_chksum_driver = NULL;
goto out;
}
}
set_buffer_verified(bh);
return 0;
@ -1591,6 +1602,8 @@ 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_wbuf);
kfree(journal);
@ -1707,6 +1720,18 @@ int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
sb->s_feature_compat &=
~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
/* Load the checksum driver */
if (journal->j_chksum_driver == NULL) {
journal->j_chksum_driver = crypto_alloc_shash("crc32c",
0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD: Cannot load crc32c "
"driver.\n");
journal->j_chksum_driver = NULL;
return 0;
}
}
}
/* If enabling v1 checksums, downgrade superblock */

23
include/linux/jbd2.h
View file

@ -31,6 +31,7 @@
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <crypto/hash.h>
#endif
#define journal_oom_retry 1
@ -965,6 +966,9 @@ struct journal_s
* superblock pointer here
*/
void *j_private;
/* Reference to checksum algorithm driver via cryptoapi */
struct crypto_shash *j_chksum_driver;
};
/*
@ -1294,6 +1298,25 @@ static inline int jbd_space_needed(journal_t *journal)
extern int jbd_blocks_per_page(struct inode *inode);
static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
const void *address, unsigned int length)
{
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(journal->j_chksum_driver)];
} desc;
int err;
desc.shash.tfm = journal->j_chksum_driver;
desc.shash.flags = 0;
*(u32 *)desc.ctx = crc;
err = crypto_shash_update(&desc.shash, address, length);
BUG_ON(err);
return *(u32 *)desc.ctx;
}
#ifdef __KERNEL__
#define buffer_trace_init(bh) do {} while (0)