Re: HEADS UP ON -DEVELOPMENT

[Garance A Drosihn <drosih@xxxxxxx>]

At 9:23 AM -0700 8/5/05, Matthew Dillon wrote:
>     Joerg and I have discussed the struct stat and struct dirent
>     changes.  So far the stat work has been committed and the dirent
>     work is still in progress.  This is work to increase ino_t from
>     32 to 64 bits and nlink_t from 16 to 32 bits.

How about dev_t to 64 bits?  For "worldwide" distributed filesystems
(such as OpenAFS), this would be a very nice thing.

> At 5:42 PM +0100 8/5/05, Hiten Pandya wrote:
> > What about time related fields, are they currently 64-bits wide?
>
>     We are stuck with various time standards so there isn't much
>     we can do with the time fields.  The standards idiots didn't
>     fix the seconds  field when they changed the microseconds
>     field to nanoseconds.

One thing I considered is coming up with a "struct_time_t" macro.
This could be used to at least *reserve* 64-bit areas in a struct
for any struct where a time_t value is used.  That way, if you
later want to have a 64-bit time_t, you'll have the room reserved
for it.  I'm hoping to get something like this together for
FreeBSD 7.x, when I'm in a particularly optimistic mood...

Something along the lines of:

#include <sys/cdefs.h>
#include <sys/types.h>

/* This uses specific sizes, and then some other include file
 * would set the real time_t to either time32_t or time64_t. */
typedef	int32_t	time32_t;
typedef	int64_t	time64_t;

#if _BYTE_ORDER == _LITTLE_ENDIAN
#define	STRUCT_TIME_T(vname) \
	union __aligned(8) { \
		time64_t	__CONCAT(vname,_64); \
		struct { \
			time32_t	vname; \
			int32_t		__CONCAT(vname,_h32); \
		}; \
	}
#elif _BYTE_ORDER == _BIG_ENDIAN
#define	STRUCT_TIME_T(vname) \
	union __aligned(8) { \
		time64_t	__CONCAT(vname,_64); \
		struct { \
			int32_t		__CONCAT(vname,_h32); \
			time32_t	vname; \
		}; \
	}
#endif

(which I have done some limited testing with, and it seems to do
what I want it to do).  You would use it like:

struct test_stat {
	...
	dev_t	  st_rdev;		/* device type */
	STRUCT_TIME_T(st_atime);	/* time of last access */
	long	  st_atimensec;		/* nsec of last access */
	STRUCT_TIME_T(st_mtime);	/* time of last data modification */
	long	  st_mtimensec;		/* nsec of last data modification */
	STRUCT_TIME_T(st_ctime);	/* time of last file status change */
	long	  st_ctimensec;		/* nsec of last file status change */
	char abyte;
};

--
Garance Alistair Drosehn            =   gad@xxxxxxxxxxxxxxxxxxxx
Senior Systems Programmer           or  gad@xxxxxxxxxxx
Rensselaer Polytechnic Institute    or  drosih@xxxxxxx