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
Init()66 Callout::Init()
67 {
68 signal(SIGALRM, Callout::AlarmSignalHandler);
69 }
70
71 bool
Stop()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
Reset(const timeval & interval,CalloutFunc_t * func,void * arg)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
AlarmSignalHandler(int)146 Callout::AlarmSignalHandler(int)
147 {
148 s_alarmFired = true;
149 ZfsDaemon::WakeEventLoop();
150 }
151
152 void
ExpireCallouts()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
TimeRemaining() const187 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