1 /*- 2 * Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions, and the following disclaimer, 10 * without modification. 11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer 12 * substantially similar to the "NO WARRANTY" disclaimer below 13 * ("Disclaimer") and any redistribution must be conditioned upon 14 * including a substantially similar Disclaimer requirement for further 15 * binary redistribution. 16 * 17 * NO WARRANTY 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGES. 29 * 30 * Authors: Justin T. Gibbs (Spectra Logic Corporation) 31 * 32 * $FreeBSD$ 33 */ 34 35 /** 36 * \file callout.cc 37 * 38 * \brief Implementation of the Callout class - multi-client 39 * timer services built on top of the POSIX interval timer. 40 */ 41 42 #include <sys/time.h> 43 44 #include <signal.h> 45 #include <syslog.h> 46 47 #include <climits> 48 #include <list> 49 #include <map> 50 #include <string> 51 52 #include <devdctl/guid.h> 53 #include <devdctl/event.h> 54 #include <devdctl/event_factory.h> 55 #include <devdctl/consumer.h> 56 #include <devdctl/exception.h> 57 58 #include "callout.h" 59 #include "vdev_iterator.h" 60 #include "zfsd.h" 61 #include "zfsd_exception.h" 62 63 std::list<Callout *> Callout::s_activeCallouts; 64 bool Callout::s_alarmFired(false); 65 66 void 67 Callout::Init() 68 { 69 signal(SIGALRM, Callout::AlarmSignalHandler); 70 } 71 72 bool 73 Callout::Stop() 74 { 75 if (!IsPending()) 76 return (false); 77 78 for (std::list<Callout *>::iterator it(s_activeCallouts.begin()); 79 it != s_activeCallouts.end(); it++) { 80 if (*it != this) 81 continue; 82 83 it = s_activeCallouts.erase(it); 84 if (it != s_activeCallouts.end()) { 85 86 /* 87 * Maintain correct interval for the 88 * callouts that follow the just removed 89 * entry. 90 */ 91 timeradd(&(*it)->m_interval, &m_interval, 92 &(*it)->m_interval); 93 } 94 break; 95 } 96 m_pending = false; 97 return (true); 98 } 99 100 bool 101 Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg) 102 { 103 bool cancelled(false); 104 105 if (!timerisset(&interval)) 106 throw ZfsdException("Callout::Reset: interval of 0"); 107 108 cancelled = Stop(); 109 110 m_interval = interval; 111 m_func = func; 112 m_arg = arg; 113 m_pending = true; 114 115 std::list<Callout *>::iterator it(s_activeCallouts.begin()); 116 for (; it != s_activeCallouts.end(); it++) { 117 118 if (timercmp(&(*it)->m_interval, &m_interval, <=)) { 119 /* 120 * Decrease our interval by those that come 121 * before us. 122 */ 123 timersub(&m_interval, &(*it)->m_interval, &m_interval); 124 } else { 125 /* 126 * Account for the time between the newly 127 * inserted event and those that follow. 128 */ 129 timersub(&(*it)->m_interval, &m_interval, 130 &(*it)->m_interval); 131 break; 132 } 133 } 134 s_activeCallouts.insert(it, this); 135 136 137 if (s_activeCallouts.front() == this) { 138 itimerval timerval = { {0, 0}, m_interval }; 139 140 setitimer(ITIMER_REAL, &timerval, NULL); 141 } 142 143 return (cancelled); 144 } 145 146 void 147 Callout::AlarmSignalHandler(int) 148 { 149 s_alarmFired = true; 150 ZfsDaemon::WakeEventLoop(); 151 } 152 153 void 154 Callout::ExpireCallouts() 155 { 156 if (!s_alarmFired) 157 return; 158 159 s_alarmFired = false; 160 if (s_activeCallouts.empty()) { 161 /* Callout removal/SIGALRM race was lost. */ 162 return; 163 } 164 165 /* 166 * Expire the first callout (the one we used to set the 167 * interval timer) as well as any callouts following that 168 * expire at the same time (have a zero interval from 169 * the callout before it). 170 */ 171 do { 172 Callout *cur(s_activeCallouts.front()); 173 s_activeCallouts.pop_front(); 174 cur->m_pending = false; 175 cur->m_func(cur->m_arg); 176 } while (!s_activeCallouts.empty() 177 && timerisset(&s_activeCallouts.front()->m_interval) == 0); 178 179 if (!s_activeCallouts.empty()) { 180 Callout *next(s_activeCallouts.front()); 181 itimerval timerval = { { 0, 0 }, next->m_interval }; 182 183 setitimer(ITIMER_REAL, &timerval, NULL); 184 } 185 } 186 187 timeval 188 Callout::TimeRemaining() const 189 { 190 /* 191 * Outline: Add the m_interval for each callout in s_activeCallouts 192 * ahead of this, except for the first callout. Add to that the result 193 * of getitimer (That's because the first callout stores its original 194 * interval setting while the timer is ticking). 195 */ 196 itimerval timervalToAlarm; 197 timeval timeToExpiry; 198 std::list<Callout *>::iterator it; 199 200 if (!IsPending()) { 201 timeToExpiry.tv_sec = INT_MAX; 202 timeToExpiry.tv_usec = 999999; /*maximum normalized value*/ 203 return (timeToExpiry); 204 } 205 206 timerclear(&timeToExpiry); 207 getitimer(ITIMER_REAL, &timervalToAlarm); 208 timeval& timeToAlarm = timervalToAlarm.it_value; 209 timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry); 210 211 it =s_activeCallouts.begin(); 212 it++; /*skip the first callout in the list*/ 213 for (; it != s_activeCallouts.end(); it++) { 214 timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry); 215 if ((*it) == this) 216 break; 217 } 218 return (timeToExpiry); 219 } 220