Re: [PATCH] fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 29 Jan 2009 02:29:11 +0530
Ankit Jain <me@ankitjain.org> wrote:

> --- xfs.orig/include/linux/falloc.h	2009-01-21 21:03:28.076324621 +0100
> +++ xfs/include/linux/falloc.h	2009-01-27 20:36:59.190423995 +0100
> @@ -3,4 +3,48 @@
>  
>  #define FALLOC_FL_KEEP_SIZE	0x01 /* default is extend size */
>  
> +#ifdef __KERNEL__
> +
> +/*
> + * Space reservation ioctls and argument structure
> + * are designed to be compatible with the legacy XFS ioctls.
> + */
> +struct space_resv {
> +	__s16		l_type;
> +	__s16		l_whence;
> +	__s64		l_start;
> +	__s64		l_len;		/* len == 0 means until end of file */
> +	__s32		l_sysid;
> +	__u32		l_pid;
> +	__s32		l_pad[4];	/* reserve area			    */
> +};
> +
> +#define F_IOC_RESVSP		_IOW('X', 40, struct space_resv)
> +#define F_IOC_RESVSP64		_IOW('X', 42, struct space_resv)

Should this stuff be inside #ifdef __KERNEL__?  It is shared with userspace.

Are we sure that the aligment of l_start will be reliably the same
across all compilers and versions thereof for all time?