GFS2: Fix error handling when reading an invalid block from the journal

When we read an invalid block from the journal, we should not call
withdraw, but simply print a message and return an error. It is
up to the caller to then handle that error. In the case of mount
that means a failed mount, rather than a withdraw (requiring a
reboot). In the case of recovering another nodes journal then
we return an error via the uevent.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/lops.c

@@ -401,9 +401,14 @@ static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 		goto out;
 	set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
 	set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
-	gfs2_meta_check(sdp, bd->bd_bh);
-	gfs2_pin(sdp, bd->bd_bh);
 	mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
+	if (unlikely(mh->mh_magic != cpu_to_be32(GFS2_MAGIC))) {
+		printk(KERN_ERR
+		       "Attempting to add uninitialised block to journal (inplace block=%lld)\n",
+		       (unsigned long long)bd->bd_bh->b_blocknr);
+		BUG();
+	}
+	gfs2_pin(sdp, bd->bd_bh);
 	mh->__pad0 = cpu_to_be64(0);
 	mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
 	sdp->sd_log_num_buf++;

fs/gfs2/util.h

@@ -79,23 +79,19 @@ int gfs2_meta_check_ii(struct gfs2_sbd *sdp, struct buffer_head *bh,
 		       const char *type, const char *function,
 		       char *file, unsigned int line);
 
-static inline int gfs2_meta_check_i(struct gfs2_sbd *sdp,
-				    struct buffer_head *bh,
-				    const char *function,
-				    char *file, unsigned int line)
+static inline int gfs2_meta_check(struct gfs2_sbd *sdp,
+				    struct buffer_head *bh)
 {
 	struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 	u32 magic = be32_to_cpu(mh->mh_magic);
-	if (unlikely(magic != GFS2_MAGIC))
-		return gfs2_meta_check_ii(sdp, bh, "magic number", function,
-					  file, line);
+	if (unlikely(magic != GFS2_MAGIC)) {
+		printk(KERN_ERR "GFS2: Magic number missing at %llu\n",
+		       (unsigned long long)bh->b_blocknr);
+		return -EIO;
+	}
 	return 0;
 }
 
-#define gfs2_meta_check(sdp, bh) \
-gfs2_meta_check_i((sdp), (bh), __func__, __FILE__, __LINE__)
-
-
 int gfs2_metatype_check_ii(struct gfs2_sbd *sdp, struct buffer_head *bh,
 			   u16 type, u16 t,
 			   const char *function,