Re: [patch 3/3] Fix XFS_IOC_FSBULKSTAT{,_SINGLE} and XFS_IOC_FSINUMBERS in compat mode

[Michal Marek <mmarek@suse.cz>]

David Chinner wrote:
> On Tue, Jun 19, 2007 at 03:25:52PM +0200, mmarek@suse.cz wrote:
>> +static int xfs_bulkstat_one_compat(
>> +	xfs_mount_t	*mp,		/* mount point for filesystem */
>> +	xfs_ino_t	ino,		/* inode number to get data for */
>> +	void		__user *buffer,	/* buffer to place output in */
>> +	int		ubsize,		/* size of buffer */
>> +	void		*private_data,	/* my private data */
>> +	xfs_daddr_t	bno,		/* starting bno of inode cluster */
>> +	int		*ubused,	/* bytes used by me */
>> +	void		*dibuff,	/* on-disk inode buffer */
>> +	int		*stat)		/* BULKSTAT_RV_... */
> 
> Hmmm - this is almost all duplicated code. It's pretty much what I
> described, but maybe not /quite/ what I had in mind here. It's a
> *big* improvement on the first version, but it seems now that the
> only real difference xfs_bulkstat_one() and
> xfs_bulkstat_one_compat() is copy_to_user() vs the discrete put_user
> calls.
> 
> I think we can remove xfs_bulkstat_one_compat() completely by using
> the same method you used with the xfs_inumber_fmt functions.

You mean xfs_ioc_bulkstat_compat() -> native xfs_bulkstat() -> native
xfs_bulkstat_one() -> a compat output formatter, so a
pointer-to-function passed to pointer-to-function? ;) I could (ab)use
the void *private_data arg which xfs_bulkstat passes unmodified to the
formatter; xfs_bulkstat_one() doesn't make use of it atm. I'll try it
and post the result in a while.

Michal