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nfsd41: Backchannel: Setup sequence information 

Follows the model used by the NFS client.  Setup the RPC prepare and done
function pointers so that we can populate the sequence information if
minorversion == 1.  rpc_run_task() is then invoked directly just like
existing NFS client operations do.

nfsd4_cb_prepare() determines if the sequence information needs to be setup.
If the slot is in use, it adds itself to the wait queue.

nfsd4_cb_done() wakes anyone sleeping on the callback channel wait queue
after our RPC reply has been received.  It also sets the task message
result pointer to NULL to clearly indicate we're done using it.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
[define and initialize cl_cb_seq_nr here]
[pulled out unused defintion of nfsd4_cb_done]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
Ricardo Labiaga 2009-09-10 12:26:38 +03:00 committed by J. Bruce Fields
parent 199ff35e1c
commit 2a1d1b5938
3 changed files with 64 additions and 0 deletions
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62
fs/nfsd/nfs4callback.c
View File

@ -501,6 +501,67 @@ nfsd4_probe_callback(struct nfs4_client *clp)
do_probe_callback(clp);
}
/*
* There's currently a single callback channel slot.
* If the slot is available, then mark it busy. Otherwise, set the
* thread for sleeping on the callback RPC wait queue.
*/
static int nfsd41_cb_setup_sequence(struct nfs4_client *clp,
struct rpc_task *task)
{
struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
u32 *ptr = (u32 *)clp->cl_sessionid.data;
int status = 0;
dprintk("%s: %u:%u:%u:%u\n", __func__,
ptr[0], ptr[1], ptr[2], ptr[3]);
if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
dprintk("%s slot is busy\n", __func__);
status = -EAGAIN;
goto out;
}
/*
* We'll need the clp during XDR encoding and decoding,
* and the sequence during decoding to verify the reply
*/
args->args_seq.cbs_clp = clp;
task->tk_msg.rpc_resp = &args->args_seq;
out:
dprintk("%s status=%d\n", __func__, status);
return status;
}
/*
* TODO: cb_sequence should support referring call lists, cachethis, multiple
* slots, and mark callback channel down on communication errors.
*/
static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
{
struct nfs4_delegation *dp = calldata;
struct nfs4_client *clp = dp->dl_client;
struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
u32 minorversion = clp->cl_cb_conn.cb_minorversion;
int status = 0;
args->args_seq.cbs_minorversion = minorversion;
if (minorversion) {
status = nfsd41_cb_setup_sequence(clp, task);
if (status) {
if (status != -EAGAIN) {
/* terminate rpc task */
task->tk_status = status;
task->tk_action = NULL;
}
return;
}
}
rpc_call_start(task);
}
static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
{
struct nfs4_delegation *dp = calldata;
@ -540,6 +601,7 @@ static void nfsd4_cb_recall_release(void *calldata)
}
static const struct rpc_call_ops nfsd4_cb_recall_ops = {
.rpc_call_prepare = nfsd4_cb_prepare,
.rpc_call_done = nfsd4_cb_recall_done,
.rpc_release = nfsd4_cb_recall_release,
};

1
fs/nfsd/nfs4state.c
View File

@ -1331,6 +1331,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
unconf->cl_cb_conn.cb_minorversion =
cstate->minorversion;
unconf->cl_cb_conn.cb_prog = cr_ses->callback_prog;
unconf->cl_cb_seq_nr = 1;
nfsd4_probe_callback(unconf);
}
conf = unconf;

1
include/linux/nfsd/state.h
View File

@ -221,6 +221,7 @@ struct nfs4_client {
/* for nfs41 callbacks */
/* We currently support a single back channel with a single slot */
unsigned long cl_cb_slot_busy;
u32 cl_cb_seq_nr;
struct svc_xprt *cl_cb_xprt; /* 4.1 callback transport */
struct rpc_wait_queue cl_cb_waitq; /* backchannel callers may */
/* wait here for slots */