Commit 01b5adce authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o
Browse files

jbd2: Grab a reference to the crc32c driver if necessary 



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

Signed-off-by: default avatarDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 25ed6e8a

fs/jbd2/Kconfig

+2 −0
Original line number Diff line number Diff line 
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

fs/jbd2/journal.c

+25 −0
Original line number Diff line number Diff line
@@ -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 */

include/linux/jbd2.h

+23 −0
Original line number Diff line number Diff line
@@ -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)