udf: Fortify LVID loading

A user has reported an oops in udf_statfs() that was caused by
numOfPartitions entry in LVID structure being corrupted. Fix the problem
by verifying whether numOfPartitions makes sense at least to the extent
that LVID fits into a single block as it should.

Reported-by: Juergen Weigert <jw@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index ed401e9..1f32c7b 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -162,7 +162,7 @@
 	return sb->s_fs_info;
 }
 
-struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct udf_sb_info *sbi);
+struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct super_block *sb);
 
 int udf_compute_nr_groups(struct super_block *sb, u32 partition);