[0/3] Fuse definitions for virtiofs

Message

Dr. David Alan Gilbert Aug. 2, 2019, 5:15 p.m. UTC

From: "Dr. David Alan Gilbert" <[e-mail]>

Hi,
  Virtiofs is a fuse-over-virtio filesystem to allow
virtual machines to access a fileystem easily, it's
currently in development, and we'd like to try and
get some of our structures and commands stabilised.
Since it runs over virtio, a spec is currently running through
the virtio standardisation process, and they'd like to
see the additional Fuse commands nailed down.  Also we'd
like to stop chasing bit/command number allocation.

The additions included here provide a performance feature
that lets the daemon map files into the hypervisor and thus
guests address space, allowing a DAX like mapping.

Note:
  For you following these patches in virtiofs, I've
made three changes:
     a) Remove the unused 'fh' field from removemapping
     b) Change the 'map_alignment' field to be log2(size) and
        use up the current uint16_t padding rather than eating
        a fresh uint32_t
     c) Moved FUSE_MAP_ALIGNMENT along one bit since
        FUSE_EXPLICIT_INVAL_DATA used up bit 25.

References:
    virtiofs home page: https://virtio-fs.gitlab.io/
    virtio-fs specification patches: https://lists.oasis-open.org/archives/virtio-dev/201907/msg00052.html

Dave

Dr. David Alan Gilbert (3):
  fuse: Add 'setupmapping'
  fuse: add 'removemapping'
  fuse: Add map_alignment for setup/remove mapping

 include/uapi/linux/fuse.h | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)