[Cluster-devel] Re: [GFS2] Fix crc32 calculation in recovery.c [8/70]

[Jan Engelhardt]

>Commit "[GFS2] split and annotate gfs2_log_head" resulted in an incorrect
>checksum calculation for log headers. This patch corrects the
>problem without resorting to copying the whole log header as
>the previous code used to.
>
>Cc: Al Viro <viro at zeniv.linux.org.uk>
>Signed-off-by: Steven Whitehouse <swhiteho at redhat.com>
>---
> fs/gfs2/recovery.c |    9 +++++----
> 1 files changed, 5 insertions(+), 4 deletions(-)
>
>diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
>index 4478162..4acf238 100644
>--- a/fs/gfs2/recovery.c
>+++ b/fs/gfs2/recovery.c
>@@ -136,6 +136,7 @@ static int get_log_header(struct gfs2_jd
> {
> 	struct buffer_head *bh;
> 	struct gfs2_log_header_host lh;
>+static const u32 nothing = 0;
> 	u32 hash;
> 	int error;
> 

At least indent it.

>@@ -143,11 +144,11 @@ static int get_log_header(struct gfs2_jd
> 	if (error)
> 		return error;
> 
>-	memcpy(&lh, bh->b_data, sizeof(struct gfs2_log_header));	/* XXX */
>-	lh.lh_hash = 0;
>-	hash = gfs2_disk_hash((char *)&lh, sizeof(struct gfs2_log_header));
>+	hash = crc32_le((u32)~0, bh->b_data, sizeof(struct gfs2_log_header) -
>+					     sizeof(u32));
>+	hash = crc32_le(hash, (unsigned char const *)&nothing, sizeof(nothing));
>+	hash ^= (u32)~0;
> 	gfs2_log_header_in(&lh, bh->b_data);
>-
> 	brelse(bh);
> 
> 	if (lh.lh_header.mh_magic != GFS2_MAGIC ||
>-- 
>1.4.1


	-`J'
--