Commit a20d1ceb authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

jbd2: fix portability problems caused by unaligned accesses 



This commit applies the e2fsck/recovery.c portions of commit
1e0c8ca7c08a ("e2fsck: fix portability problems caused by unaligned
accesses) from the e2fsprogs git tree.

The on-disk format for the ext4 journal can have unaigned 32-bit
integers.  This can happen when replaying a journal using a obsolete
checksum format (which was never popularly used, since the v3 format
replaced v2 while the metadata checksum feature was being stablized).

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 877ba3f7

fs/jbd2/recovery.c

+11 −11
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf) 
static int count_tags(journal_t *journal, struct buffer_head *bh)

{

	char *			tagp;

	journal_block_tag_t *	tag;

	journal_block_tag_t	tag;

	int			nr = 0, size = journal->j_blocksize;

	int			tag_bytes = journal_tag_bytes(journal);
@@ -206,14 +206,14 @@ static int count_tags(journal_t *journal, struct buffer_head *bh) 
	tagp = &bh->b_data[sizeof(journal_header_t)];



	while ((tagp - bh->b_data + tag_bytes) <= size) {

		tag = (journal_block_tag_t *) tagp;

		memcpy(&tag, tagp, sizeof(tag));



		nr++;

		tagp += tag_bytes;

		if (!(tag->t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))

		if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))

			tagp += 16;



		if (tag->t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))

		if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))

			break;

	}
@@ -433,9 +433,9 @@ static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 
}



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

				      journal_block_tag3_t *tag3,

				      void *buf, __u32 sequence)

{

	journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;

	__u32 csum32;

	__be32 seq;
@@ -496,7 +496,7 @@ static int do_one_pass(journal_t *journal, 
	while (1) {

		int			flags;

		char *			tagp;

		journal_block_tag_t *	tag;

		journal_block_tag_t	tag;

		struct buffer_head *	obh;

		struct buffer_head *	nbh;
@@ -613,8 +613,8 @@ static int do_one_pass(journal_t *journal, 
			       <= journal->j_blocksize - descr_csum_size) {

				unsigned long io_block;



				tag = (journal_block_tag_t *) tagp;

				flags = be16_to_cpu(tag->t_flags);

				memcpy(&tag, tagp, sizeof(tag));

				flags = be16_to_cpu(tag.t_flags);



				io_block = next_log_block++;

				wrap(journal, next_log_block);
@@ -632,7 +632,7 @@ static int do_one_pass(journal_t *journal, 


					J_ASSERT(obh != NULL);

					blocknr = read_tag_block(journal,

								 tag);

								 &tag);



					/* If the block has been

					 * revoked, then we're all done
@@ -647,8 +647,8 @@ static int do_one_pass(journal_t *journal, 


					/* Look for block corruption */

					if (!jbd2_block_tag_csum_verify(

						journal, tag, obh->b_data,

						be32_to_cpu(tmp->h_sequence))) {

			journal, &tag, (journal_block_tag3_t *)tagp,

			obh->b_data, be32_to_cpu(tmp->h_sequence))) {

						brelse(obh);

						success = -EFSBADCRC;

						printk(KERN_ERR "JBD2: Invalid "