From f092075dd33ea04000590e8ffea65c2e7d03d764 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 21 May 2012 22:45:41 -0400 Subject: 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 Signed-off-by: Trond Myklebust --- fs/nfs/client.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/nfs/client.c') diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 9b9df71df09a..af9b7e4b9df2 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -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 -- cgit v1.2.3