140 lines
4.6 KiB
C
140 lines
4.6 KiB
C
/*
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* fs/nfs/nfs4renewd.c
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*
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* Copyright (c) 2002 The Regents of the University of Michigan.
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* All rights reserved.
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*
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* Kendrick Smith <kmsmith@umich.edu>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Implementation of the NFSv4 "renew daemon", which wakes up periodically to
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* send a RENEW, to keep state alive on the server. The daemon is implemented
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* as an rpc_task, not a real kernel thread, so it always runs in rpciod's
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* context. There is one renewd per nfs_server.
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*
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* TODO: If the send queue gets backlogged (e.g., if the server goes down),
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* we will keep filling the queue with periodic RENEW requests. We need a
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* mechanism for ensuring that if renewd successfully sends off a request,
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* then it only wakes up when the request is finished. Maybe use the
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* child task framework of the RPC layer?
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*/
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/sunrpc/sched.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/nfs.h>
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#include <linux/nfs4.h>
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#include <linux/nfs_fs.h>
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#include "nfs4_fs.h"
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#include "delegation.h"
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#define NFSDBG_FACILITY NFSDBG_PROC
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void
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nfs4_renew_state(struct work_struct *work)
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{
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struct nfs4_state_maintenance_ops *ops;
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struct nfs_client *clp =
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container_of(work, struct nfs_client, cl_renewd.work);
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struct rpc_cred *cred;
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long lease, timeout;
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unsigned long last, now;
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ops = nfs4_state_renewal_ops[clp->cl_minorversion];
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dprintk("%s: start\n", __func__);
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/* Are there any active superblocks? */
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if (list_empty(&clp->cl_superblocks))
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goto out;
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spin_lock(&clp->cl_lock);
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lease = clp->cl_lease_time;
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last = clp->cl_last_renewal;
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now = jiffies;
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timeout = (2 * lease) / 3 + (long)last - (long)now;
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/* Are we close to a lease timeout? */
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if (time_after(now, last + lease/3)) {
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cred = ops->get_state_renewal_cred_locked(clp);
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spin_unlock(&clp->cl_lock);
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if (cred == NULL) {
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if (list_empty(&clp->cl_delegations)) {
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set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
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goto out;
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}
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nfs_expire_all_delegations(clp);
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} else {
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/* Queue an asynchronous RENEW. */
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ops->sched_state_renewal(clp, cred);
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put_rpccred(cred);
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}
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timeout = (2 * lease) / 3;
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spin_lock(&clp->cl_lock);
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} else
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dprintk("%s: failed to call renewd. Reason: lease not expired \n",
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__func__);
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if (timeout < 5 * HZ) /* safeguard */
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timeout = 5 * HZ;
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dprintk("%s: requeueing work. Lease period = %ld\n",
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__func__, (timeout + HZ - 1) / HZ);
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cancel_delayed_work(&clp->cl_renewd);
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schedule_delayed_work(&clp->cl_renewd, timeout);
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spin_unlock(&clp->cl_lock);
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nfs_expire_unreferenced_delegations(clp);
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out:
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dprintk("%s: done\n", __func__);
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}
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void
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nfs4_schedule_state_renewal(struct nfs_client *clp)
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{
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long timeout;
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spin_lock(&clp->cl_lock);
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timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
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- (long)jiffies;
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if (timeout < 5 * HZ)
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timeout = 5 * HZ;
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dprintk("%s: requeueing work. Lease period = %ld\n",
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__func__, (timeout + HZ - 1) / HZ);
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cancel_delayed_work(&clp->cl_renewd);
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schedule_delayed_work(&clp->cl_renewd, timeout);
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set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
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spin_unlock(&clp->cl_lock);
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}
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void
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nfs4_kill_renewd(struct nfs_client *clp)
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{
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cancel_delayed_work_sync(&clp->cl_renewd);
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}
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/*
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* Local variables:
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* c-basic-offset: 8
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* End:
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*/
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