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Commit f092075d authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

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: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 2c820d9a

fs/nfs/client.c

+1 −1
Original line number Diff line number Diff line
@@ -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

fs/nfs/netns.h

+5 −0
Original line number Diff line number Diff line 
/*

 * 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;

fs/nfs/nfs4proc.c

+8 −6
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ 
#include "iostat.h"

#include "callback.h"

#include "pnfs.h"

#include "netns.h"



#define NFSDBG_FACILITY		NFSDBG_PROC
@@ -3903,7 +3904,7 @@ 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,

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",

fs/nfs/nfs4xdr.c

+4 −1
Original line number Diff line number Diff line
@@ -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 */

include/linux/nfs_fs_sb.h

+0 −3
Original line number Diff line number Diff line
@@ -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;