Commit c3900875 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o
Browse files

jbd2: checksum data blocks that are stored in the journal 



Calculate and verify checksums of each data block being stored in the journal.

Signed-off-by: default avatarDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 1f56c589

fs/jbd2/commit.c

+22 −0
Original line number Diff line number Diff line
@@ -338,6 +338,26 @@ static void jbd2_descr_block_csum_set(journal_t *j, 
	tail->t_checksum = cpu_to_be32(csum);

}



static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,

				    struct buffer_head *bh, __u32 sequence)

{

	struct page *page = bh->b_page;

	__u8 *addr;

	__u32 csum;



	if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))

		return;



	sequence = cpu_to_be32(sequence);

	addr = kmap_atomic(page, KM_USER0);

	csum = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,

			  sizeof(sequence));

	csum = jbd2_chksum(j, csum, addr + offset_in_page(bh->b_data),

			  bh->b_size);

	kunmap_atomic(addr, KM_USER0);



	tag->t_checksum = cpu_to_be32(csum);

}

/*

 * jbd2_journal_commit_transaction

 *
@@ -669,6 +689,8 @@ void jbd2_journal_commit_transaction(journal_t *journal) 
		tag = (journal_block_tag_t *) tagp;

		write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);

		tag->t_flags = cpu_to_be16(tag_flag);

		jbd2_block_tag_csum_set(journal, tag, jh2bh(new_jh),

					commit_transaction->t_tid);

		tagp += tag_bytes;

		space_left -= tag_bytes;

fs/jbd2/journal.c

+8 −2
Original line number Diff line number Diff line
@@ -2097,10 +2097,16 @@ int jbd2_journal_blocks_per_page(struct inode *inode) 
 */

size_t journal_tag_bytes(journal_t *journal)

{

	journal_block_tag_t tag;

	size_t x = 0;



	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))

		x += sizeof(tag.t_checksum);



	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))

		return JBD2_TAG_SIZE64;

		return x + JBD2_TAG_SIZE64;

	else

		return JBD2_TAG_SIZE32;

		return x + JBD2_TAG_SIZE32;

}



/*

fs/jbd2/recovery.c

+30 −0
Original line number Diff line number Diff line
@@ -393,6 +393,23 @@ static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 
	return provided == calculated;

}



static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,

				      void *buf, __u32 sequence)

{

	__u32 provided, calculated;



	if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))

		return 1;



	sequence = cpu_to_be32(sequence);

	calculated = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,

				 sizeof(sequence));

	calculated = jbd2_chksum(j, calculated, buf, j->j_blocksize);

	provided = be32_to_cpu(tag->t_checksum);



	return provided == cpu_to_be32(calculated);

}



static int do_one_pass(journal_t *journal,

			struct recovery_info *info, enum passtype pass)

{
@@ -569,6 +586,19 @@ static int do_one_pass(journal_t *journal, 
						goto skip_write;

					}



					/* Look for block corruption */

					if (!jbd2_block_tag_csum_verify(

						journal, tag, obh->b_data,

						be32_to_cpu(tmp->h_sequence))) {

						brelse(obh);

						success = -EIO;

						printk(KERN_ERR "JBD: Invalid "

						       "checksum recovering "

						       "block %llu in log\n",

						       blocknr);

						continue;

					}



					/* Find a buffer for the new

					 * data being restored */

					nbh = __getblk(journal->j_fs_dev,