ext4: suppress verbose debugging information if malloc-debug is off

If CONFIG_EXT4_DEBUG is enabled, then if a block allocation fails due
to disk being full, a verbose debugging message is printed, even if
the malloc-debug switch has not been enabled.  Suppress the debugging
message so that nothing is printed unless malloc-debug has been turned
on.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/mballoc.c

@@ -3912,7 +3912,8 @@ static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
 	struct super_block *sb = ac->ac_sb;
 	ext4_group_t ngroups, i;
 
-	if (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
+	if (!mb_enable_debug ||
+	    (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
 		return;
 
 	printk(KERN_ERR "EXT4-fs: Can't allocate:"