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

Michal Marek
2007-07-02T09:40:39Z

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