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 33 /** 34 * \file callout.cc 35 * 36 * \brief Implementation of the Callout class - multi-client 37 * timer services built on top of the POSIX interval timer. 38 */ 39 40 #include <sys/byteorder.h> 41 #include <sys/time.h> 42 43 #include <signal.h> 44 #include <syslog.h> 45 46 #include <climits> 47 #include <list> 48 #include <map> 49 #include <string> 50 51 #include <devdctl/guid.h> 52 #include <devdctl/event.h> 53 #include <devdctl/event_factory.h> 54 #include <devdctl/consumer.h> 55 #include <devdctl/exception.h> 56 57 #include "callout.h" 58 #include "vdev_iterator.h" 59 #include "zfsd.h" 60 #include "zfsd_exception.h" 61 62 std::list<Callout *> Callout::s_activeCallouts; 63 bool Callout::s_alarmFired(false); 64 65 void 66 Callout::Init() 67 { 68 signal(SIGALRM, Callout::AlarmSignalHandler); 69 } 70 71 bool 72 Callout::Stop() 73 { 74 if (!IsPending()) 75 return (false); 76 77 for (std::list<Callout *>::iterator it(s_activeCallouts.begin()); 78 it != s_activeCallouts.end(); it++) { 79 if (*it != this) 80 continue; 81 82 it = s_activeCallouts.erase(it); 83 if (it != s_activeCallouts.end()) { 84 85 /* 86 * Maintain correct interval for the 87 * callouts that follow the just removed 88 * entry. 89 */ 90 timeradd(&(*it)->m_interval, &m_interval, 91 &(*it)->m_interval); 92 } 93 break; 94 } 95 m_pending = false; 96 return (true); 97 } 98 99 bool 100 Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg) 101 { 102 bool cancelled(false); 103 104 if (!timerisset(&interval)) 105 throw ZfsdException("Callout::Reset: interval of 0"); 106 107 cancelled = Stop(); 108 109 m_interval = interval; 110 m_func = func; 111 m_arg = arg; 112 m_pending = true; 113 114 std::list<Callout *>::iterator it(s_activeCallouts.begin()); 115 for (; it != s_activeCallouts.end(); it++) { 116 117 if (timercmp(&(*it)->m_interval, &m_interval, <=)) { 118 /* 119 * Decrease our interval by those that come 120 * before us. 121 */ 122 timersub(&m_interval, &(*it)->m_interval, &m_interval); 123 } else { 124 /* 125 * Account for the time between the newly 126 * inserted event and those that follow. 127 */ 128 timersub(&(*it)->m_interval, &m_interval, 129 &(*it)->m_interval); 130 break; 131 } 132 } 133 s_activeCallouts.insert(it, this); 134 135 136 if (s_activeCallouts.front() == this) { 137 itimerval timerval = { {0, 0}, m_interval }; 138 139 setitimer(ITIMER_REAL, &timerval, NULL); 140 } 141 142 return (cancelled); 143 } 144 145 void 146 Callout::AlarmSignalHandler(int) 147 { 148 s_alarmFired = true; 149 ZfsDaemon::WakeEventLoop(); 150 } 151 152 void 153 Callout::ExpireCallouts() 154 { 155 if (!s_alarmFired) 156 return; 157 158 s_alarmFired = false; 159 if (s_activeCallouts.empty()) { 160 /* Callout removal/SIGALRM race was lost. */ 161 return; 162 } 163 164 /* 165 * Expire the first callout (the one we used to set the 166 * interval timer) as well as any callouts following that 167 * expire at the same time (have a zero interval from 168 * the callout before it). 169 */ 170 do { 171 Callout *cur(s_activeCallouts.front()); 172 s_activeCallouts.pop_front(); 173 cur->m_pending = false; 174 cur->m_func(cur->m_arg); 175 } while (!s_activeCallouts.empty() 176 && timerisset(&s_activeCallouts.front()->m_interval) == 0); 177 178 if (!s_activeCallouts.empty()) { 179 Callout *next(s_activeCallouts.front()); 180 itimerval timerval = { { 0, 0 }, next->m_interval }; 181 182 setitimer(ITIMER_REAL, &timerval, NULL); 183 } 184 } 185 186 timeval 187 Callout::TimeRemaining() const 188 { 189 /* 190 * Outline: Add the m_interval for each callout in s_activeCallouts 191 * ahead of this, except for the first callout. Add to that the result 192 * of getitimer (That's because the first callout stores its original 193 * interval setting while the timer is ticking). 194 */ 195 itimerval timervalToAlarm; 196 timeval timeToExpiry; 197 std::list<Callout *>::iterator it; 198 199 if (!IsPending()) { 200 timeToExpiry.tv_sec = INT_MAX; 201 timeToExpiry.tv_usec = 999999; /*maximum normalized value*/ 202 return (timeToExpiry); 203 } 204 205 timerclear(&timeToExpiry); 206 getitimer(ITIMER_REAL, &timervalToAlarm); 207 timeval& timeToAlarm = timervalToAlarm.it_value; 208 timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry); 209 210 it =s_activeCallouts.begin(); 211 it++; /*skip the first callout in the list*/ 212 for (; it != s_activeCallouts.end(); it++) { 213 timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry); 214 if ((*it) == this) 215 break; 216 } 217 return (timeToExpiry); 218 } 219