From db9ee220361de03ee86388f9ea5e529eaad5323c Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Wed, 27 Aug 2014 18:40:07 -0400 Subject: jbd2: fix descriptor block size handling errors with journal_csum It turns out that there are some serious problems with the on-disk format of journal checksum v2. The foremost is that the function to calculate descriptor tag size returns sizes that are too big. This causes alignment issues on some architectures and is compounded by the fact that some parts of jbd2 use the structure size (incorrectly) to determine the presence of a 64bit journal instead of checking the feature flags. Therefore, introduce journal checksum v3, which enlarges the descriptor block tag format to allow for full 32-bit checksums of journal blocks, fix the journal tag function to return the correct sizes, and fix the jbd2 recovery code to use feature flags to determine 64bitness. Add a few function helpers so we don't have to open-code quite so many pieces. Switching to a 16-byte block size was found to increase journal size overhead by a maximum of 0.1%, to convert a 32-bit journal with no checksumming to a 32-bit journal with checksum v3 enabled. Signed-off-by: Darrick J. Wong Reported-by: TR Reardon Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- fs/jbd2/revoke.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/jbd2/revoke.c') diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c index 198c9c10276d..d5e95a175c92 100644 --- a/fs/jbd2/revoke.c +++ b/fs/jbd2/revoke.c @@ -91,8 +91,8 @@ #include #include #include -#endif #include +#endif static struct kmem_cache *jbd2_revoke_record_cache; static struct kmem_cache *jbd2_revoke_table_cache; @@ -597,7 +597,7 @@ static void write_one_revoke_record(journal_t *journal, 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)) + if (jbd2_journal_has_csum_v2or3(journal)) csum_size = sizeof(struct jbd2_journal_revoke_tail); /* Make sure we have a descriptor with space left for the record */ @@ -644,7 +644,7 @@ static void jbd2_revoke_csum_set(journal_t *j, struct buffer_head *bh) struct jbd2_journal_revoke_tail *tail; __u32 csum; - if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) + if (!jbd2_journal_has_csum_v2or3(j)) return; tail = (struct jbd2_journal_revoke_tail *)(bh->b_data + j->j_blocksize - -- cgit v1.2.3