Re: [patch 6/9] fuse: add export operations

[Christoph Hellwig <hch@infradead.org>]

> +struct fuse_inode_handle
> +{
> +	u64 nodeid;
> +	u32 generation;
> +};

This is the same filehandle type XFS uses for 64bit inode filesystems
where the parent is not encoded.  I'll post a patch soon to move that
64bit inode handling to common code.  I don't think it's a good idea
to delay your patch until that happens, but can you chose the fid
types to be the same as XFS does currently so that a conversion is
easily possible.  The fh_type should be 0x81 (fh type 1 order by 0x80
to imply it's 64bit inodes)

In case you want to look at that patch I'v uploaded the current
version at http://verein.lst.de/~hch/generic-64bit-inode-export

> +static struct dentry *fuse_get_dentry(struct super_block *sb,
> +				      struct fuse_inode_handle *handle)
> +{
> +	struct inode *inode;
> +	struct dentry *entry;
> +	int err = -ESTALE;
> +
> +	if (handle->nodeid == 0)
> +		goto out_err;
> +
> +	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
> +	if (!inode)
> +		goto out_err;

Only finding in-memory inodes for nfs export is quite dangerous.  I
think it would be a much better idea to support whatever upcalls are
needed to find the object if it's not in memory.  Without that the nfs
exporting support is hardly useable.