[GFS2] Fix crc32 calculation in recovery.c

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@zeniv.linux.org.uk>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index 4478162..4acf238 100644 (file)
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -136,6 +136,7 @@ static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
 {
        struct buffer_head *bh;
        struct gfs2_log_header_host lh;
+static const u32 nothing = 0;
        u32 hash;
        int error;
 
@@ -143,11 +144,11 @@ static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
        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 ||