cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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nfs4renewd.c (4595B)

      1/*
      2 *  fs/nfs/nfs4renewd.c
      3 *
      4 *  Copyright (c) 2002 The Regents of the University of Michigan.
      5 *  All rights reserved.
      6 *
      7 *  Kendrick Smith <kmsmith@umich.edu>
      8 *
      9 *  Redistribution and use in source and binary forms, with or without
     10 *  modification, are permitted provided that the following conditions
     11 *  are met:
     12 *
     13 *  1. Redistributions of source code must retain the above copyright
     14 *     notice, this list of conditions and the following disclaimer.
     15 *  2. Redistributions in binary form must reproduce the above copyright
     16 *     notice, this list of conditions and the following disclaimer in the
     17 *     documentation and/or other materials provided with the distribution.
     18 *  3. Neither the name of the University nor the names of its
     19 *     contributors may be used to endorse or promote products derived
     20 *     from this software without specific prior written permission.
     21 *
     22 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
     23 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     24 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     25 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     27 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     28 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
     29 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     30 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     31 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     32 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     33 *
     34 * Implementation of the NFSv4 "renew daemon", which wakes up periodically to
     35 * send a RENEW, to keep state alive on the server.  The daemon is implemented
     36 * as an rpc_task, not a real kernel thread, so it always runs in rpciod's
     37 * context.  There is one renewd per nfs_server.
     38 *
     39 */
     40
     41#include <linux/mm.h>
     42#include <linux/pagemap.h>
     43#include <linux/sunrpc/sched.h>
     44#include <linux/sunrpc/clnt.h>
     45
     46#include <linux/nfs.h>
     47#include <linux/nfs4.h>
     48#include <linux/nfs_fs.h>
     49#include "nfs4_fs.h"
     50#include "delegation.h"
     51
     52#define NFSDBG_FACILITY		NFSDBG_STATE
     53
     54void
     55nfs4_renew_state(struct work_struct *work)
     56{
     57	const struct nfs4_state_maintenance_ops *ops;
     58	struct nfs_client *clp =
     59		container_of(work, struct nfs_client, cl_renewd.work);
     60	const struct cred *cred;
     61	long lease;
     62	unsigned long last, now;
     63	unsigned renew_flags = 0;
     64
     65	ops = clp->cl_mvops->state_renewal_ops;
     66	dprintk("%s: start\n", __func__);
     67
     68	if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))
     69		goto out;
     70
     71	lease = clp->cl_lease_time;
     72	last = clp->cl_last_renewal;
     73	now = jiffies;
     74	/* Are we close to a lease timeout? */
     75	if (time_after(now, last + lease/3))
     76		renew_flags |= NFS4_RENEW_TIMEOUT;
     77	if (nfs_delegations_present(clp))
     78		renew_flags |= NFS4_RENEW_DELEGATION_CB;
     79
     80	if (renew_flags != 0) {
     81		cred = ops->get_state_renewal_cred(clp);
     82		if (cred == NULL) {
     83			if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {
     84				set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
     85				goto out;
     86			}
     87			nfs_expire_all_delegations(clp);
     88		} else {
     89			int ret;
     90
     91			/* Queue an asynchronous RENEW. */
     92			ret = ops->sched_state_renewal(clp, cred, renew_flags);
     93			put_cred(cred);
     94			switch (ret) {
     95			default:
     96				goto out_exp;
     97			case -EAGAIN:
     98			case -ENOMEM:
     99				break;
    100			}
    101		}
    102	} else {
    103		dprintk("%s: failed to call renewd. Reason: lease not expired \n",
    104				__func__);
    105	}
    106	nfs4_schedule_state_renewal(clp);
    107out_exp:
    108	nfs_expire_unreferenced_delegations(clp);
    109out:
    110	dprintk("%s: done\n", __func__);
    111}
    112
    113void
    114nfs4_schedule_state_renewal(struct nfs_client *clp)
    115{
    116	long timeout;
    117
    118	spin_lock(&clp->cl_lock);
    119	timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal
    120		- (long)jiffies;
    121	if (timeout < 5 * HZ)
    122		timeout = 5 * HZ;
    123	dprintk("%s: requeueing work. Lease period = %ld\n",
    124			__func__, (timeout + HZ - 1) / HZ);
    125	mod_delayed_work(system_wq, &clp->cl_renewd, timeout);
    126	set_bit(NFS_CS_RENEWD, &clp->cl_res_state);
    127	spin_unlock(&clp->cl_lock);
    128}
    129
    130void
    131nfs4_kill_renewd(struct nfs_client *clp)
    132{
    133	cancel_delayed_work_sync(&clp->cl_renewd);
    134}
    135
    136/**
    137 * nfs4_set_lease_period - Sets the lease period on a nfs_client
    138 *
    139 * @clp: pointer to nfs_client
    140 * @lease: new value for lease period
    141 */
    142void nfs4_set_lease_period(struct nfs_client *clp,
    143		unsigned long lease)
    144{
    145	spin_lock(&clp->cl_lock);
    146	clp->cl_lease_time = lease;
    147	spin_unlock(&clp->cl_lock);
    148
    149	/* Cap maximum reconnect timeout at 1/2 lease period */
    150	rpc_set_connect_timeout(clp->cl_rpcclient, lease, lease >> 1);
    151}