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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>
This commit is contained in:
Chuck Lever 2012-05-21 22:45:41 -04:00 committed by Trond Myklebust
parent 2c820d9a97
commit f092075dd3
5 changed files with 18 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/nfs/client.c
View File

@ -184,7 +184,6 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
spin_lock_init(&clp->cl_lock);
INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
clp->cl_boot_time = CURRENT_TIME;
clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
clp->cl_minorversion = cl_init->minorversion;
clp->cl_mvops = nfs_v4_minor_ops[cl_init->minorversion];
@ -1813,6 +1812,7 @@ void nfs_clients_init(struct net *net)
idr_init(&nn->cb_ident_idr);
#endif
spin_lock_init(&nn->nfs_client_lock);
nn->boot_time = CURRENT_TIME;
}
#ifdef CONFIG_PROC_FS

5
fs/nfs/netns.h
View File

@ -1,3 +1,7 @@
/*
* NFS-private data for each "struct net". Accessed with net_generic().
*/
#ifndef __NFS_NETNS_H__
#define __NFS_NETNS_H__
@ -20,6 +24,7 @@ struct nfs_net {
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;

14
fs/nfs/nfs4proc.c
View File

@ -64,6 +64,7 @@
#include "iostat.h"
#include "callback.h"
#include "pnfs.h"
#include "netns.h"
#define NFSDBG_FACILITY NFSDBG_PROC
@ -3903,8 +3904,8 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server,
return -EAGAIN;
}
static void nfs4_construct_boot_verifier(struct nfs_client *clp,
nfs4_verifier *bootverf)
static void nfs4_init_boot_verifier(const struct nfs_client *clp,
nfs4_verifier *bootverf)
{
__be32 verf[2];
@ -3914,8 +3915,9 @@ static void nfs4_construct_boot_verifier(struct nfs_client *clp,
verf[0] = 0;
verf[1] = (__be32)(NSEC_PER_SEC + 1);
} else {
verf[0] = (__be32)clp->cl_boot_time.tv_sec;
verf[1] = (__be32)clp->cl_boot_time.tv_nsec;
struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
verf[0] = (__be32)nn->boot_time.tv_sec;
verf[1] = (__be32)nn->boot_time.tv_nsec;
}
memcpy(bootverf->data, verf, sizeof(bootverf->data));
}
@ -3939,7 +3941,7 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
int loop = 0;
int status;
nfs4_construct_boot_verifier(clp, &sc_verifier);
nfs4_init_boot_verifier(clp, &sc_verifier);
for(;;) {
rcu_read_lock();
@ -5099,7 +5101,7 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
dprintk("--> %s\n", __func__);
BUG_ON(clp == NULL);
nfs4_construct_boot_verifier(clp, &verifier);
nfs4_init_boot_verifier(clp, &verifier);
args.id_len = scnprintf(args.id, sizeof(args.id),
"%s/%s/%u",

5
fs/nfs/nfs4xdr.c
View File

@ -53,9 +53,11 @@
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_idmap.h>
#include "nfs4_fs.h"
#include "internal.h"
#include "pnfs.h"
#include "netns.h"
#define NFSDBG_FACILITY NFSDBG_XDR
@ -1702,6 +1704,7 @@ static void encode_create_session(struct xdr_stream *xdr,
char machine_name[NFS4_MAX_MACHINE_NAME_LEN];
uint32_t len;
struct nfs_client *clp = args->client;
struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
u32 max_resp_sz_cached;
/*
@ -1743,7 +1746,7 @@ static void encode_create_session(struct xdr_stream *xdr,
*p++ = cpu_to_be32(RPC_AUTH_UNIX); /* auth_sys */
/* authsys_parms rfc1831 */
*p++ = cpu_to_be32((u32)clp->cl_boot_time.tv_nsec); /* stamp */
*p++ = (__be32)nn->boot_time.tv_nsec; /* stamp */
p = xdr_encode_opaque(p, machine_name, len);
*p++ = cpu_to_be32(0); /* UID */
*p++ = cpu_to_be32(0); /* GID */

3
include/linux/nfs_fs_sb.h
View File

@ -61,9 +61,6 @@ struct nfs_client {
struct rpc_wait_queue cl_rpcwaitq;
/* used for the setclientid verifier */
struct timespec cl_boot_time;
/* idmapper */
struct idmap * cl_idmap;