On Sat, 7 Aug 2010 06:34:00 -0400 Jeff Layton <jlayton@xxxxxxxxx> wrote: > On Sat, 7 Aug 2010 13:32:40 +1000 > Neil Brown <neilb@xxxxxxx> wrote: > > > So we are left with an attribute that is needed for windows compatibility, > > and so just needs to be understood by samba and wine. Some filesystems might > > support it efficiently, others might require the use of generic > > extended-attributes, still others might not support it at all (I guess you > > store it in some 'tdb' and hope it works well enough). > > > > Core-linux doesn't really need to know about this - there just needs to be a > > channel to pass it between samba/wine and the filesystem. xattr still seems > > the best mechanism to pass this stuff around. Team-samba can negotiate with > > fs developers to optimise/accelerate certain attributes, and linux-VFS > > doesn't need to know or care (except maybe to provide generic non-blocking or > > multiple-access interfaces). > > > > IIUC, you're saying that we should basically just have samba stuff the > current time into an xattr when it creates the file and leave the > filesystems alone. If so, I disagree here. I'm not quite saying that (though there is a temptation). Some attributes are initialised by the filesystem rather than by common code. i_uid is a simple example. I have no problem with the filesystem initialising the storage that is used for this well-known-EA to the current time at creation. This would be part of what team-samba negotiated with FS developers. > > The problem with treating this as *just* an xattr is that it doesn't > account for files that are created outside of samba but are then shared > out by it. If something is created in a different universe, then brought into this one - when is its date of birth? The moment of creation, or the moment of entry into this universe? If both universes have a common time line (altough with a 10 year offset) then I guess the former, though I think it is a bit of a philosophical point.... :-) > > To handle this correctly, I believe it needs to be initialized by the > kernel to the current time whenever an inode is created, even if samba > doesn't create it. After that, it can be treated as just another xattr. > Yes, I suspect that would be ideal, and trivial for the fs to implement (it has to initialise it to something after all). i.e. I agree. 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
