On Mon, 2009-10-19 at 12:55 -0600, Andreas Dilger wrote: > On 19-Oct-09, at 11:17, Steve French wrote: > > A new version of the format for Samba server related file system > > extended attributes is expected in the next version of Samba so the > > topic of create time and nanosecond timestamps for Linux has come up > > again. Since some file systems don't support storing create time > > (birth time), and none support updating create time, or for that > > matter for storing any nanosecond timestamps at all (a millisecond > > seems like a much longer time today than when the stat structure was > > defined), and dos attributes, Samba server stores these in extended > > attributes, which is awkward on those file systems which store > > (different) versions of these on disk. > > I had proposed in the past that these file attributes be exposed to > userspace as virtual xattrs, e.g. user.cr_time returning a struct > timespec, but the data is stored internal to the filesystem in whatever > format is most efficient for it. We only strictly need user.crtime > for this, but I wouldn't object to exporting other inode attributes in > this way (e.g. user.mtime, user.atime, etc). > > I believe that nanosecond timestamps ARE supported with newer > filesystems > using stat(). There is the utimensat() system call, which takes a > timespec > parameter, so it looks to be suitable for setting nanosecond timestamps > from userspace. I don't know if glibc() supports this, but I do see it > in the kernel. > How we are going to set the nanotimestamps today? utimes(2) man page seems indicating it only support setting time at microseond level. > As for _updating_ create time, isn't that sort of defeating the purpose > of create time? > Perphas the backup/restore wants to preserve the original creation timestamp after the file being backuped? > Cheers, Andreas > -- > Andreas Dilger > Sr. Staff Engineer, Lustre Group > Sun Microsystems of Canada, Inc. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
