linux/fs/nfs/netns.h
Chuck Lever f092075dd3 NFS: Always use the same SETCLIENTID boot verifier
Currently our NFS client assigns a unique SETCLIENTID boot verifier
for each server IP address it knows about.  It's set to CURRENT_TIME
when the struct nfs_client for that server IP is created.

During the SETCLIENTID operation, our client also presents an
nfs_client_id4 string to servers, as an identifier on which the server
can hang all of this client's NFSv4 state.  Our client's
nfs_client_id4 string is unique for each server IP address.

An NFSv4 server is obligated to wipe all NFSv4 state associated with
an nfs_client_id4 string when the client presents the same
nfs_client_id4 string along with a changed SETCLIENTID boot verifier.

When our client unmounts the last of a server's shares, it destroys
that server's struct nfs_client.  The next time the client mounts that
NFS server, it creates a fresh struct nfs_client with a fresh boot
verifier.  On seeing the fresh verifer, the server wipes any previous
NFSv4 state associated with that nfs_client_id4.

However, NFSv4.1 clients are supposed to present the same
nfs_client_id4 string to all servers.  And, to support Transparent
State Migration, the same nfs_client_id4 string should be presented
to all NFSv4.0 servers so they recognize that migrated state for this
client belongs with state a server may already have for this client.
(This is known as the Uniform Client String model).

If the nfs_client_id4 string is the same but the boot verifier changes
for each server IP address, SETCLIENTID and EXCHANGE_ID operations
from such a client could unintentionally result in a server wiping a
client's previously obtained lease.

Thus, if our NFS client is going to use a fixed nfs_client_id4 string,
either for NFSv4.0 or NFSv4.1 mounts, our NFS client should use a
boot verifier that does not change depending on server IP address.
Replace our current per-nfs_client boot verifier with a per-nfs_net
boot verifier.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-05-22 16:45:46 -04:00

33 lines
660 B
C

/*
* NFS-private data for each "struct net". Accessed with net_generic().
*/
#ifndef __NFS_NETNS_H__
#define __NFS_NETNS_H__
#include <net/net_namespace.h>
#include <net/netns/generic.h>
struct bl_dev_msg {
int32_t status;
uint32_t major, minor;
};
struct nfs_net {
struct cache_detail *nfs_dns_resolve;
struct rpc_pipe *bl_device_pipe;
struct bl_dev_msg bl_mount_reply;
wait_queue_head_t bl_wq;
struct list_head nfs_client_list;
struct list_head nfs_volume_list;
#ifdef CONFIG_NFS_V4
struct idr cb_ident_idr; /* Protected by nfs_client_lock */
#endif
spinlock_t nfs_client_lock;
struct timespec boot_time;
};
extern int nfs_net_id;
#endif