On Thu, 22 Jul 2010 10:24:17 -0700 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > Of people can just use xattrs and do it all entirely in user space. I > assume that's what samba does now, even outside of birthtime. Much as I despise xattrs, this would definitely be my preference. ctime and mtime have real cache-coherence semantics which require them being updated by the kernel (whether the cache is on an NFS client, in a backup archive, or in a .o translation of a .c file). create-time, on the other hand, would never be updated by the kernel, and might sometimes be updated by an application. So it is a very different sort of attribute, much like a hypothetical 'last archived' time. The only role the kernel might have would be setting the 'creation time' when the file was created, but it seems even that isn't always what is wanted, because people don't so much what the time of create of the container-on-disk, but the time of creation of the data-content. I would want to see a pretty convincing use-case that cannot be solved with xattrs before 'creation time' was added to a generic kernel interface. So just use xattrs and don't involve the kernel in any detailed knowledge of this value. Maybe xstat should take a list of xattrs to be retrieved as well?? or maybe not. But I hope the xstat debate doesn't get bogged down about whether 'create time' is sensible or not. Quite apart from the ability to return more attributes, I think it has real value is being able to return fewer attributes, and being allowed to ask for 'best guess' values. Being able to do an 'fstat' and being certain that you won't be blocked by a non-responsive NFS server would be a GOOD THING (TM). NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
