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 * TODO: If the send queue gets backlogged (e.g., if the server goes down), 40 * we will keep filling the queue with periodic RENEW requests. We need a 41 * mechanism for ensuring that if renewd successfully sends off a request, 42 * then it only wakes up when the request is finished. Maybe use the 43 * child task framework of the RPC layer? 44 */ 45 46 #include <linux/sched.h> 47 #include <linux/smp_lock.h> 48 #include <linux/mm.h> 49 #include <linux/pagemap.h> 50 #include <linux/sunrpc/sched.h> 51 #include <linux/sunrpc/clnt.h> 52 53 #include <linux/nfs.h> 54 #include <linux/nfs4.h> 55 #include <linux/nfs_fs.h> 56 #include "nfs4_fs.h" 57 58 #define NFSDBG_FACILITY NFSDBG_PROC 59 60 void 61 nfs4_renew_state(void *data) 62 { 63 struct nfs4_client *clp = (struct nfs4_client *)data; 64 long lease, timeout; 65 unsigned long last, now; 66 67 down_read(&clp->cl_sem); 68 dprintk("%s: start\n", __FUNCTION__); 69 /* Are there any active superblocks? */ 70 if (list_empty(&clp->cl_superblocks)) 71 goto out; 72 spin_lock(&clp->cl_lock); 73 lease = clp->cl_lease_time; 74 last = clp->cl_last_renewal; 75 now = jiffies; 76 timeout = (2 * lease) / 3 + (long)last - (long)now; 77 /* Are we close to a lease timeout? */ 78 if (time_after(now, last + lease/3)) { 79 spin_unlock(&clp->cl_lock); 80 /* Queue an asynchronous RENEW. */ 81 nfs4_proc_async_renew(clp); 82 timeout = (2 * lease) / 3; 83 spin_lock(&clp->cl_lock); 84 } else 85 dprintk("%s: failed to call renewd. Reason: lease not expired \n", 86 __FUNCTION__); 87 if (timeout < 5 * HZ) /* safeguard */ 88 timeout = 5 * HZ; 89 dprintk("%s: requeueing work. Lease period = %ld\n", 90 __FUNCTION__, (timeout + HZ - 1) / HZ); 91 cancel_delayed_work(&clp->cl_renewd); 92 schedule_delayed_work(&clp->cl_renewd, timeout); 93 spin_unlock(&clp->cl_lock); 94 out: 95 up_read(&clp->cl_sem); 96 dprintk("%s: done\n", __FUNCTION__); 97 } 98 99 /* Must be called with clp->cl_sem locked for writes */ 100 void 101 nfs4_schedule_state_renewal(struct nfs4_client *clp) 102 { 103 long timeout; 104 105 spin_lock(&clp->cl_lock); 106 timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal 107 - (long)jiffies; 108 if (timeout < 5 * HZ) 109 timeout = 5 * HZ; 110 dprintk("%s: requeueing work. Lease period = %ld\n", 111 __FUNCTION__, (timeout + HZ - 1) / HZ); 112 cancel_delayed_work(&clp->cl_renewd); 113 schedule_delayed_work(&clp->cl_renewd, timeout); 114 spin_unlock(&clp->cl_lock); 115 } 116 117 void 118 nfs4_renewd_prepare_shutdown(struct nfs_server *server) 119 { 120 struct nfs4_client *clp = server->nfs4_state; 121 122 if (!clp) 123 return; 124 flush_scheduled_work(); 125 down_write(&clp->cl_sem); 126 if (!list_empty(&server->nfs4_siblings)) 127 list_del_init(&server->nfs4_siblings); 128 up_write(&clp->cl_sem); 129 } 130 131 /* Must be called with clp->cl_sem locked for writes */ 132 void 133 nfs4_kill_renewd(struct nfs4_client *clp) 134 { 135 down_read(&clp->cl_sem); 136 if (!list_empty(&clp->cl_superblocks)) { 137 up_read(&clp->cl_sem); 138 return; 139 } 140 cancel_delayed_work(&clp->cl_renewd); 141 up_read(&clp->cl_sem); 142 flush_scheduled_work(); 143 } 144 145 /* 146 * Local variables: 147 * c-basic-offset: 8 148 * End: 149 */ 150