[Linux-cachefs] [fuse-devel] [Gluster-devel] Feature proposal - FS-Cache support in FUSE

[Anand Avati]

On Wed, Sep 10, 2014 at 7:20 AM, Miklos Szeredi <miklos at szeredi.hu> wrote:
>
> >> This would be a challenge with any FUSE based filesystem which has
> >> persistent filehandles larger than 64bit.
>
> Fuse does provide a total of 128bits of file handle identification
> with nodeID + generation, with some of that number-space reserved for
> special uses, unfortunately.
>
> Would be nice to provide for arbitrary file handle lengths.   Will
> look into that, at least for the libfuse-3.0 API.
>

This is something beyond the libfuse API. Unless the kernel/user ABI is
modified to present the entire 128bits with each call (i.e, both nodeID +
generation instead of just nodeID) we are still bound to provide unique
64bit nodeID (and persistent for anything living across umount/mount). This
is perhaps the biggest reason why GlusterFS implemented its own NFS server
for v3 and uses NFS-Ganesha for v4, instead of using kNFSd.

Thanks