ext4: enable block_validity by default

Enable by default the block_validity feature, which checks for
collisions between newly allocated blocks and critical system
metadata.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 896e452..7194a51 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3519,8 +3519,8 @@
 		set_opt(sb, ERRORS_CONT);
 	else
 		set_opt(sb, ERRORS_RO);
-	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
-		set_opt(sb, BLOCK_VALIDITY);
+	/* block_validity enabled by default; disable with noblock_validity */
+	set_opt(sb, BLOCK_VALIDITY);
 	if (def_mount_opts & EXT4_DEFM_DISCARD)
 		set_opt(sb, DISCARD);