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author | Chuck Lever <chuck.lever@oracle.com> | 2012-05-21 22:45:41 -0400 |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-05-22 16:45:46 -0400 |
commit | f092075dd33ea04000590e8ffea65c2e7d03d764 (patch) | |
tree | 626ce6b85084d50e9d2d81e32850e494eadbc8cb /fs/nfs/netns.h | |
parent | 2c820d9a97f07b273b2c8a5960bd52b1b5864c68 (diff) | |
download | linux-f092075dd33ea04000590e8ffea65c2e7d03d764.tar.gz linux-f092075dd33ea04000590e8ffea65c2e7d03d764.tar.bz2 linux-f092075dd33ea04000590e8ffea65c2e7d03d764.zip |
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')
-rw-r--r-- | fs/nfs/netns.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h index aa14ec303e94..8a6394edb8b0 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 */ #endif spinlock_t nfs_client_lock; + struct timespec boot_time; }; extern int nfs_net_id; |