Re: vfs dmapi handle generation problem

[Christoph Hellwig <hch@infradead.org>]

On Wed, Jun 04, 2008 at 03:55:04PM +0200, Tim J?dicke wrote:
> int
> vfs_dm_inode_to_fh(struct inode *ip, dm_fid_t *dmfid, dm_fsid_t *dmfsid)
> {
>    dmfid->dm_fid_len = sizeof(dm_fid_t) - sizeof(dmfid->dm_fid_len);
>    dmfid->dm_fid_pad = 0;
>    memcpy(&dmfid->dm_fid_ino, &ip->i_ino, sizeof(dmfid->dm_fid_ino));
>    dmfid->dm_fid_gen = ip->i_generation;
> 
>    *dmfsid = 11; // need generation system
> 
>    return 0;

i_ino in struct inode is unsigned long.  If you run the above code
on a 32bit system you'll get crap in the upper half of dm_fid_ino.

Try:

int
vfs_dm_inode_to_fh(struct inode *ip, dm_fid_t *dmfid, dm_fsid_t *dmfsid)
{
	dmfid->dm_fid_len = sizeof(dm_fid_t) - sizeof(dmfid->dm_fid_len);
	dmfid->dm_fid_pad = 0;
	dmfid->dm_fid_ino = ip->i_ino;
	dmfid->dm_fid_gen = ip->i_generation;

	*dmfsid = 11; // need generation system
	return 0;
}

instead.  If you actually want to support 64bit inode numbers on 32bit
systems you'll have to query for it with vfs_getattr, though.