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authorChuck Lever <chuck.lever@oracle.com>2012-09-15 01:24:11 +0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-10-02 02:33:33 +0400
commit896526174ce2b6a773e187ebe5a047b68230e2c4 (patch)
tree0f994ab0746003d4a6355086b24051664c89612d /include/linux/nfs_fs_sb.h
parentba9b584c1dc37851d9c6ca6d0d2ccba55d9aad04 (diff)
downloadlinux-896526174ce2b6a773e187ebe5a047b68230e2c4.tar.xz
NFS: Introduce "migration" mount option
Currently, the Linux client uses a unique nfs_client_id4.id string when identifying itself to distinct NFS servers. To support transparent state migration, the Linux client will have to use the same nfs_client_id4 string for all servers it communicates with (also known as the "uniform client string" approach). Otherwise NFS servers can not recognize that open and lock state need to be merged after a file system transition. Unfortunately, there are some NFSv4.0 servers currently in the field that do not tolerate the uniform client string approach. Thus, by default, our NFSv4.0 mounts will continue to use the current approach, and we introduce a mount option that switches them to use the uniform model. Client administrators must identify which servers can be mounted with this option. Eventually most NFSv4.0 servers will be able to handle the uniform approach, and we can change the default. The first mount of a server controls the behavior for all subsequent mounts for the lifetime of that set of mounts of that server. After the last mount of that server is gone, the client erases the data structure that tracks the lease. A subsequent lease may then honor a different "migration" setting. This patch adds only the infrastructure for parsing the new mount option. Support for uniform client strings is added in a subsequent patch. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'include/linux/nfs_fs_sb.h')
-rw-r--r--include/linux/nfs_fs_sb.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 310c63c8ab2c..2e22fc7e47cf 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -39,6 +39,7 @@ struct nfs_client {
unsigned long cl_flags; /* behavior switches */
#define NFS_CS_NORESVPORT 0 /* - use ephemeral src port */
#define NFS_CS_DISCRTRY 1 /* - disconnect on RPC retry */
+#define NFS_CS_MIGRATION 2 /* - transparent state migr */
struct sockaddr_storage cl_addr; /* server identifier */
size_t cl_addrlen;
char * cl_hostname; /* hostname of server */
@@ -125,6 +126,7 @@ struct nfs_server {
unsigned int namelen;
unsigned int options; /* extra options enabled by mount */
#define NFS_OPTION_FSCACHE 0x00000001 /* - local caching enabled */
+#define NFS_OPTION_MIGRATION 0x00000002 /* - NFSv4 migration enabled */
struct nfs_fsid fsid;
__u64 maxfilesize; /* maximum file size */