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Commit 42a7106d authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o
Browse files

jbd2: checksum revocation blocks 



Compute and verify revoke blocks inside 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 4fd5ea43

fs/jbd2/recovery.c

+22 −0
Original line number Diff line number Diff line
@@ -706,6 +706,25 @@ static int do_one_pass(journal_t *journal, 
	return err;

}



static int jbd2_revoke_block_csum_verify(journal_t *j,

					 void *buf)

{

	struct jbd2_journal_revoke_tail *tail;

	__u32 provided, calculated;



	if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))

		return 1;



	tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -

			sizeof(struct jbd2_journal_revoke_tail));

	provided = tail->r_checksum;

	tail->r_checksum = 0;

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

	tail->r_checksum = provided;



	provided = be32_to_cpu(provided);

	return provided == calculated;

}



/* Scan a revoke record, marking all blocks mentioned as revoked. */
@@ -720,6 +739,9 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, 
	offset = sizeof(jbd2_journal_revoke_header_t);

	max = be32_to_cpu(header->r_count);



	if (!jbd2_revoke_block_csum_verify(journal, header))

		return -EINVAL;



	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))

		record_len = 8;

fs/jbd2/revoke.c

+26 −1
Original line number Diff line number Diff line
@@ -578,6 +578,7 @@ static void write_one_revoke_record(journal_t *journal, 
				    struct jbd2_revoke_record_s *record,

				    int write_op)

{

	int csum_size = 0;

	struct journal_head *descriptor;

	int offset;

	journal_header_t *header;
@@ -592,9 +593,13 @@ static void write_one_revoke_record(journal_t *journal, 
	descriptor = *descriptorp;

	offset = *offsetp;



	/* Do we need to leave space at the end for a checksum? */

	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))

		csum_size = sizeof(struct jbd2_journal_revoke_tail);



	/* Make sure we have a descriptor with space left for the record */

	if (descriptor) {

		if (offset == journal->j_blocksize) {

		if (offset >= journal->j_blocksize - csum_size) {

			flush_descriptor(journal, descriptor, offset, write_op);

			descriptor = NULL;

		}
@@ -631,6 +636,24 @@ static void write_one_revoke_record(journal_t *journal, 
	*offsetp = offset;

}



static void jbd2_revoke_csum_set(journal_t *j,

				 struct journal_head *descriptor)

{

	struct jbd2_journal_revoke_tail *tail;

	__u32 csum;



	if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))

		return;



	tail = (struct jbd2_journal_revoke_tail *)

			(jh2bh(descriptor)->b_data + j->j_blocksize -

			sizeof(struct jbd2_journal_revoke_tail));

	tail->r_checksum = 0;

	csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,

			   j->j_blocksize);

	tail->r_checksum = cpu_to_be32(csum);

}



/*

 * Flush a revoke descriptor out to the journal.  If we are aborting,

 * this is a noop; otherwise we are generating a buffer which needs to
@@ -652,6 +675,8 @@ static void flush_descriptor(journal_t *journal, 


	header = (jbd2_journal_revoke_header_t *) jh2bh(descriptor)->b_data;

	header->r_count = cpu_to_be32(offset);

	jbd2_revoke_csum_set(journal, descriptor);



	set_buffer_jwrite(bh);

	BUFFER_TRACE(bh, "write");

	set_buffer_dirty(bh);