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NFS: Migration support for RELEASE_LOCKOWNER 

Currently the Linux NFS client ignores the operation status code for
the RELEASE_LOCKOWNER operation.  Like NFSv3's UMNT operation,
RELEASE_LOCKOWNER is a courtesy to help servers manage their
resources, and the outcome is not consequential for the client.

During a migration, a server may report NFS4ERR_LEASE_MOVED, in
which case the client really should retry, since typically
LEASE_MOVED has nothing to do with the current operation, but does
prevent it from going forward.

Also, it's important for a client to respond as soon as possible to
a moved lease condition, since the client's lease could expire on
the destination without further action by the client.

NFS4ERR_DELAY is not included in the list of valid status codes for
RELEASE_LOCKOWNER in RFC 3530bis.  However, rfc3530-migration-update
does permit migration-capable servers to return DELAY to clients,
but only in the context of an ongoing migration.  In this case the
server has frozen lock state in preparation for migration, and a
client retry would help the destination server purge unneeded state
once migration recovery is complete.

Interestly, NFS4ERR_MOVED is not valid for RELEASE_LOCKOWNER, even
though lock owners can be migrated with Transparent State Migration.

Note that RFC 3530bis section 9.5 includes RELEASE_LOCKOWNER in the
list of operations that renew a client's lease on the server if they
succeed.  Now that our client pays attention to the operation's
status code, we can note that renewal appropriately.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Chuck Lever 2013-10-17 14:13:47 -04:00 committed by Trond Myklebust
parent 8ef2f8d46a
commit 60ea681299
1 changed files with 16 additions and 0 deletions
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16
fs/nfs/nfs4proc.c
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@ -5800,6 +5800,7 @@ struct nfs_release_lockowner_data {
struct nfs_release_lockowner_args args;
struct nfs4_sequence_args seq_args;
struct nfs4_sequence_res seq_res;
unsigned long timestamp;
};
static void nfs4_release_lockowner_prepare(struct rpc_task *task, void *calldata)
@ -5807,12 +5808,27 @@ static void nfs4_release_lockowner_prepare(struct rpc_task *task, void *calldata
struct nfs_release_lockowner_data *data = calldata;
nfs40_setup_sequence(data->server,
&data->seq_args, &data->seq_res, task);
data->timestamp = jiffies;
}
static void nfs4_release_lockowner_done(struct rpc_task *task, void *calldata)
{
struct nfs_release_lockowner_data *data = calldata;
struct nfs_server *server = data->server;
nfs40_sequence_done(task, &data->seq_res);
switch (task->tk_status) {
case 0:
renew_lease(server, data->timestamp);
break;
case -NFS4ERR_STALE_CLIENTID:
case -NFS4ERR_EXPIRED:
case -NFS4ERR_LEASE_MOVED:
case -NFS4ERR_DELAY:
if (nfs4_async_handle_error(task, server, NULL) == -EAGAIN)
rpc_restart_call_prepare(task);
}
}
static void nfs4_release_lockowner_release(void *calldata)