On Mon, May 22, 2023 at 8:00 PM ronnie sahlberg via samba-technical <samba-technical@xxxxxxxxxxxxxxx> wrote: > > Yeah, I don't think we should surface these as xattrs. > Xattrs are already way too small for most of the usecases of ADS on > windows (file metadata for explorer etc) > and they are also just an atomic blob and not a proper filedescriptor. > Since ADS is still just a file, any application that in the future > will use ADS features should only do so via > a proper filedescriptors, where it is possible to > seek/read/write/truncate/... so IMHO we shouldn't offer them an > alternative but inferior API. Because they might mistakenly start to use it. :-( > > There are no real applications, yet, for linux that uses ADS but there > are many that potentially could use ADS or > become ADS aware. GUI Filebrowsers would be a nice usecase. As would > making 'cp', 'mv', 'tar', 'rsync', ... ADS aware. > > So let's not do it with xattrs. > No one needs/asks for this right now so it would be code we will have > to maintain but has no users. > > > What we should do though is think about and talk with the NTFS folks > so that we make sure our aims and APIs will align with the plans they > have. > And once we have multiple filesystems supporting it (cifs.ko and ntfs) > then we can start thinking about how to encourage external users and > applications to use it. > There are really nice use-cases for ADS where one can store additional > metadata within the "file" itself. > > regards > ronnie s > > On Tue, 23 May 2023 at 02:21, Jeremy Allison <jra@xxxxxxxxx> wrote: > > > > On Mon, May 22, 2023 at 01:39:50AM -0500, Steve French wrote: > > >On Sun, May 21, 2023 at 11:33 PM ronnie sahlberg > > ><ronniesahlberg@xxxxxxxxx> wrote: > > >> > > >> A problem we have with xattrs today is that we use EAs and these are > > >> case insensitive. > > >> Even worse I think windows may also convert the names to uppercase :-( > > >> And there is no way to change it in the registry :-( > > > > > >But for alternate data streams if we allowed them to be retrieved via xattrs, > > >would case sensitivity matter? Alternate data streams IIRC are already > > >case preserving. Presumably the more common case is for a Linux user > > >to read (or backup) an existing alternate data stream (which are usually > > >created by Windows so case sensitivity would not be relevant). > > > > Warning Will Robinson ! Mixing ADS and xattrs on the client side is a receipe for > > confusion and disaster IMHO. > > > > They really are different things. No good will come of trying to mix > > the two into one client namespace. > Solaris / Illumos had a neat feature where you could say openat(fd, O_RDWR | O_XATTR) to open a stream on ZFS and then do normal file IO to the stream (pread, pwrite, etc).
