path: root/fs/nfs/netns.h
diff options
authorChuck Lever <chuck.lever@oracle.com>2012-05-21 22:45:41 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-05-22 16:45:46 -0400
commitf092075dd33ea04000590e8ffea65c2e7d03d764 (patch)
tree626ce6b85084d50e9d2d81e32850e494eadbc8cb /fs/nfs/netns.h
parent2c820d9a97f07b273b2c8a5960bd52b1b5864c68 (diff)
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>
Diffstat (limited to 'fs/nfs/netns.h')
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index aa14ec303e9..8a6394edb8b 100644
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -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 */
spinlock_t nfs_client_lock;
+ struct timespec boot_time;
extern int nfs_net_id;