Re: daddr_t is inconsistent and barely used

[Albert D. Cahalan]

Christoph Hellwig writes:
>>> In article <[e-mail]> you wrote:

>>>> The use of daddr_t in freevxfs may give different in core
>>>> and disk layouts on different machines.  Is that intended?.
...
> vx_daddr_t is for disk structures, daddr_t for core.

This is asking for trouble. The disk structures aren't about
to change. See include/linux/ext2_fs.h for a safe way to do
the on-disk structure. For the in-core stuff, "unsigned long"
is a perfectly fine data type -- and yes I know it gets wider
with a 64-bit system.

To save you the trouble of looking up my example:

/*
 * Structure of a blocks group descriptor
 */
struct ext2_group_desc
{
        __u32   bg_block_bitmap;                /* Blocks bitmap block */
        __u32   bg_inode_bitmap;                /* Inodes bitmap block */
        __u32   bg_inode_table;         /* Inodes table block */
        __u16   bg_free_blocks_count;   /* Free blocks count */
        __u16   bg_free_inodes_count;   /* Free inodes count */
        __u16   bg_used_dirs_count;     /* Directories count */
        __u16   bg_pad;
        __u32   bg_reserved[3];
};

Don't forget to add explicit padding as needed to give natural alignment.