Re: [PATCH 1/1] ntfs: add ioctl support for named data streams

On Mon, Aug 3, 2026 at 6:10=E2=80=AFPM Lionel Cons <[email protected]=
m> wrote:
>
> On Wed, 29 Jul 2026 at 13:00, Namjae Jeon <[email protected]> wrote:
> >
> > Sebastian and Cedric requested NTFS driver support for an interface tha=
t
> > WINE can use to access named data streams.
> >
> > NTFS supports multiple named $DATA attributes, commonly known as altern=
ate
> > data streams, but they are not directly accessible through the existing
> > file operations. Add NTFS-specific ioctl commands to let userspace list=
,
> > read, write, and remove named data streams on an opened file.
> >
> > The new UAPI provides separate commands for each operation:
> >
> >   - NTFS_IOC_STREAM_READ
> >   - NTFS_IOC_STREAM_WRITE
> >   - NTFS_IOC_STREAM_REMOVE
>
> Wouldn't it be better to just provide an API to get a fd, relative to
> a filename? Win32 named streams can be sparse, and it is common to
> punch holes to deallocate sections of streams too. Streams do have
> their own timestamps, too.
I believe the current ioctl interface is the best fit for this
support. It operates on an already-open base-file fd, avoids pathname
ambiguity with :, supports UTF-16 stream names, and does not require a
new system call or VFS changes. If WINE requires hole punching for
sparse streams, I can extend the ioctl interface to support it.
>
> >   - NTFS_IOC_LIST_STREAMS
>
> NTFS_IOC_LIST_STREAMS looks OK.
Thanks!