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 57 #define NFSDBG_FACILITY NFSDBG_PROC 58 59 void 60 nfs4_renew_state(void *data) 61 { 62 struct nfs4_client *clp = (struct nfs4_client *)data; 63 long lease, timeout; 64 unsigned long last, now; 65 66 down_read(&clp->cl_sem); 67 dprintk("%s: start\n", __FUNCTION__); 68 /* Are there any active superblocks? */ 69 if (list_empty(&clp->cl_superblocks)) 70 goto out; 71 spin_lock(&clp->cl_lock); 72 lease = clp->cl_lease_time; 73 last = clp->cl_last_renewal; 74 now = jiffies; 75 timeout = (2 * lease) / 3 + (long)last - (long)now; 76 /* Are we close to a lease timeout? */ 77 if (time_after(now, last + lease/3)) { 78 spin_unlock(&clp->cl_lock); 79 /* Queue an asynchronous RENEW. */ 80 nfs4_proc_async_renew(clp); 81 timeout = (2 * lease) / 3; 82 spin_lock(&clp->cl_lock); 83 } else 84 dprintk("%s: failed to call renewd. Reason: lease not expired \n", 85 __FUNCTION__); 86 if (timeout < 5 * HZ) /* safeguard */ 87 timeout = 5 * HZ; 88 dprintk("%s: requeueing work. Lease period = %ld\n", 89 __FUNCTION__, (timeout + HZ - 1) / HZ); 90 cancel_delayed_work(&clp->cl_renewd); 91 schedule_delayed_work(&clp->cl_renewd, timeout); 92 spin_unlock(&clp->cl_lock); 93 out: 94 up_read(&clp->cl_sem); 95 dprintk("%s: done\n", __FUNCTION__); 96 } 97 98 /* Must be called with clp->cl_sem locked for writes */ 99 void 100 nfs4_schedule_state_renewal(struct nfs4_client *clp) 101 { 102 long timeout; 103 104 spin_lock(&clp->cl_lock); 105 timeout = (2 * clp->cl_lease_time) / 3 + (long)clp->cl_last_renewal 106 - (long)jiffies; 107 if (timeout < 5 * HZ) 108 timeout = 5 * HZ; 109 dprintk("%s: requeueing work. Lease period = %ld\n", 110 __FUNCTION__, (timeout + HZ - 1) / HZ); 111 cancel_delayed_work(&clp->cl_renewd); 112 schedule_delayed_work(&clp->cl_renewd, timeout); 113 spin_unlock(&clp->cl_lock); 114 } 115 116 void 117 nfs4_renewd_prepare_shutdown(struct nfs_server *server) 118 { 119 struct nfs4_client *clp = server->nfs4_state; 120 121 if (!clp) 122 return; 123 flush_scheduled_work(); 124 down_write(&clp->cl_sem); 125 if (!list_empty(&server->nfs4_siblings)) 126 list_del_init(&server->nfs4_siblings); 127 up_write(&clp->cl_sem); 128 } 129 130 /* Must be called with clp->cl_sem locked for writes */ 131 void 132 nfs4_kill_renewd(struct nfs4_client *clp) 133 { 134 down_read(&clp->cl_sem); 135 if (!list_empty(&clp->cl_superblocks)) { 136 up_read(&clp->cl_sem); 137 return; 138 } 139 cancel_delayed_work(&clp->cl_renewd); 140 up_read(&clp->cl_sem); 141 flush_scheduled_work(); 142 } 143 144 /* 145 * Local variables: 146 * c-basic-offset: 8 147 * End: 148 */ 149