On Jul 16, 2012, at 3:05 PM, Myklebust, Trond wrote: > On Wed, 2012-07-11 at 16:31 -0400, Chuck Lever wrote: >> "Server trunking" is a fancy named for a multi-homed NFS server. >> Trunking might occur if a client sends NFS requests for a single >> workload to multiple network interfaces on the same server. There >> are some implications for NFSv4 state management that make it useful >> for a client to know if a single NFSv4 server instance is >> multi-homed. (Note this is only a consideration for NFSv4, not for >> legacy versions of NFS, which are stateless). >> >> If a client cares about server trunking, no NFSv4 operations can >> proceed until that client determines who it is talking to. Thus >> server IP trunking discovery must be done when the client first >> encounters an unfamiliar server IP address. >> >> The nfs_get_client() function walks the nfs_client_list and matches >> on server IP address. The outcome of that walk tells us immediately >> if we have an unfamiliar server IP address. It invokes >> nfs_init_client() in this case. Thus, nfs4_init_client() is a good >> spot to perform trunking discovery. >> >> Discovery requires a client to establish a fresh client ID, so our >> client will now send SETCLIENTID or EXCHANGE_ID as the first NFS >> operation after a successful ping, rather than waiting for an >> application to perform an operation that requires NFSv4 state. >> >> The exact process for detecting trunking is different for NFSv4.0 and >> NFSv4.1, so a minorversion-specific init_client callout method is >> introduced. >> >> CLID_INUSE recovery is important for the trunking discovery process. >> CLID_INUSE is a sign the server recognizes the client's nfs_client_id4 >> id string, but the client is using the wrong principal this time for >> the SETCLIENTID operation. The SETCLIENTID must be retried with a >> series of different principals until one works, and the rest of >> trunking discovery can proceed. >> >> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> >> --- >> >> fs/nfs/client.c | 237 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> fs/nfs/internal.h | 6 + >> fs/nfs/nfs4_fs.h | 8 ++ >> fs/nfs/nfs4proc.c | 2 >> fs/nfs/nfs4state.c | 186 ++++++++++++++++++++++++++++++++++++++++- >> 5 files changed, 433 insertions(+), 6 deletions(-) > > Applying: NFS: Discover NFSv4 server trunking when mounting > error: patch failed: fs/nfs/nfs4state.c:1656 > error: fs/nfs/nfs4state.c: patch does not apply > Patch failed at 0001 NFS: Discover NFSv4 server trunking when mounting I can take a look. What are you applying it to, exactly? -- Chuck Lever chuck[dot]lever[at]oracle[dot]com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
