On Dec 21, 2011, at 4:33 PM, Jeff Layton wrote:
> On Wed, 21 Dec 2011 15:45:01 -0500
> Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>
>>
>> On Dec 21, 2011, at 3:34 PM, Jeff Layton wrote:
>>
>>> The daemon takes a versioned binary struct. Hopefully this should allow
>>> us to revise the struct later if it becomes necessary.
>>
>> This breaks the pattern of using text-based up- and downcalls in NFSD. I assume this is binary because nfs_client_id4 is a string of opaque bytes?
>>
>
> That's the main reason. We could, of course encode that string in hex or
> something, and decode it on the other end. No one has presented a
> strong argument for doing it that way as of yet though.
>
> If anyone feels strongly about that, then it would be helpful to have
> them pipe up now and state why they do...
<pipe>Because binary data structures are difficult to work with over time, which is why other NFSD user space interfaces are text-based.</pipe>
;-)
>
>>> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
>>> ---
>>> include/linux/nfsd/cld.h | 56 ++++++++++++++++++++++++++++++++++++++++++++++
>>> 1 files changed, 56 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..d97d678
>>> --- /dev/null
>>> +++ b/include/linux/nfsd/cld.h
>>> @@ -0,0 +1,56 @@
>>> +/*
>>> + * fs/nfsd/cld.h - upcall description for nfsdcld communication
>>> + *
>>> + * Copyright (c) 2011 Red Hat, Inc.
>>> + * Author(s): Jeff Layton <jlayton@xxxxxxxxxx>
>>> + *
>>> + * 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_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, /* expire record for this cm_id */
>>> + Cld_Allow, /* is this cm_id allowed? */
>>> + Cld_GraceDone, /* grace period is complete */
>>> +};
>>> +
>>> +/* 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 */
>>> + int16_t cm_status; /* return code */
>>> + uint32_t cm_xid; /* transaction id */
>>> + union {
>>> + int64_t cm_gracetime; /* grace period start time */
>>> + struct cld_name cm_name;
>>> + } __attribute__((packed)) cm_u;
>>> +} __attribute__((packed));
>>> +
>>> +#endif /* !_NFSD_CLD_H */
>>> --
>>> 1.7.1
>>>
>>> --
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>>
>
>
> --
> Jeff Layton <jlayton@xxxxxxxxxx>
> --
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--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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