Re: [PATCH v2 4/5] nfsd: add a header describing upcall to nfsdcld

[Benny Halevy <bhalevy@tonian.com>]

On 2011-12-15 20:43, Jeff Layton wrote:
> The daemon takes a versioned binary struct. Hopefully this should allow
> us to revise the struct later if it becomes necessary.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  include/linux/nfsd/cld.h |   57 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 57 insertions(+), 0 deletions(-)
>  create mode 100644 include/linux/nfsd/cld.h
> 
> diff --git a/include/linux/nfsd/cld.h b/include/linux/nfsd/cld.h
> new file mode 100644
> index 0000000..d64a7e7
> --- /dev/null
> +++ b/include/linux/nfsd/cld.h
> @@ -0,0 +1,57 @@
> +/*
> + * fs/nfsd/cld.h - upcall description for nfsdcld communication
> + *
> + * Copyright (c) 2011 Red Hat, Inc.
> + * Author(s): Jeff Layton <jlayton@redhat.com>
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, write to the Free Software
> + *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +#ifndef _NFSD_CLD_H
> +#define _NFSD_CLD_H
> +
> +/* latest upcall version available */
> +#define CLD_MAX_UPCALL_VERSION 1
> +
> +/* defined by RFC3530 */
> +#define NFS4_OPAQUE_LIMIT 1024
> +
> +enum cld_command {
> +	Cld_Create,		/* create a record for this cm_id */
> +	Cld_Expire,		/* remove record for this cm_id */
> +	Cld_Allow,		/* is this cm_id allowed? */
> +	Cld_GraceDone,		/* grace period is complete */
> +	Cld_NrToReclaim,	/* how many client records need reclaim? */
> +};
> +
> +/* representation of long-form NFSv4 client ID */
> +struct cld_name {
> +	uint16_t	cn_len;				/* length of cm_id */
> +	unsigned char	cn_id[NFS4_OPAQUE_LIMIT];	/* client-provided */
> +} __attribute__((packed));
> +
> +/* message struct for communication with userspace */
> +struct cld_msg {
> +	uint8_t		cm_vers;		/* upcall version */
> +	uint8_t		cm_cmd;			/* upcall command */
> +	uint32_t	cm_xid;			/* transaction id */
> +	int16_t		cm_status;		/* return code */

How about swapping the xid and status members so they'd align better?

Benny

> +	union {
> +		int64_t		cm_gracetime;	/* grace period start time */
> +		struct cld_name	cm_name;
> +	} __attribute__((packed)) cm_u;
> +} __attribute__((packed));
> +
> +#endif /* !_NFSD_CLD_H */