ocfs2/o2hb: check len for bio_add_page() to avoid getting incorrect bio

We need to check len for bio_add_page() to make sure the bio has been
set up correctly, otherwise we may submit incorrect data to device.

Link: http://lkml.kernel.org/r/5ABC3EBE.5020807@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Acked-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/cluster/heartbeat.c

@@ -570,7 +570,16 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 		     current_page, vec_len, vec_start);
 
 		len = bio_add_page(bio, page, vec_len, vec_start);
-		if (len != vec_len) break;
+		if (len != vec_len) {
+			mlog(ML_ERROR, "Adding page[%d] to bio failed, "
+			     "page %p, len %d, vec_len %u, vec_start %u, "
+			     "bi_sector %llu\n", current_page, page, len,
+			     vec_len, vec_start,
+			     (unsigned long long)bio->bi_iter.bi_sector);
+			bio_put(bio);
+			bio = ERR_PTR(-EIO);
+			return bio;
+		}
 
 		cs += vec_len / (PAGE_SIZE/spp);
 		vec_start = 0;