xref: /titanic_51/usr/src/cmd/fm/fmd/common/fmd_dr.c (revision b0daa853ddd4c48b6374b8ac0dca46629b225c39)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * FMD Dynamic Reconfiguration (DR) Event Handling
28  *
29  * Fault manager scheme plug-ins must track characteristics of individual
30  * pieces of hardware.  As these components can be added or removed by a DR
31  * operation, we need to provide a means by which plug-ins can determine when
32  * they need to re-examine the current configuration.  We provide a simple
33  * mechanism whereby this task can be implemented using lazy evaluation: a
34  * simple 64-bit generation counter is maintained and incremented on *any* DR.
35  * Schemes can store the generation number in scheme-specific data structures,
36  * and then revalidate their contents if the current generation number has
37  * changed since the resource information was cached.  This method saves time,
38  * avoids the complexity of direct participation in DR, avoids the need for
39  * resource-specific processing of DR events, and is relatively easy to port
40  * to other systems that support dynamic reconfiguration.
41  *
42  * The dr generation is only incremented in response to hardware changes.  Since
43  * ASRUs can be in any scheme, including the device scheme, we must also be
44  * aware of software configuration changes which may affect the resource cache.
45  * In addition, we take a snapshot of the topology whenever a reconfiguration
46  * event occurs and notify any modules of the change.
47  */
48 
49 #include <sys/types.h>
50 #include <sys/sunddi.h>
51 #include <sys/sysevent/dr.h>
52 #include <sys/sysevent/eventdefs.h>
53 
54 #include <stdio.h>
55 #include <string.h>
56 #include <unistd.h>
57 #include <libsysevent.h>
58 
59 #undef MUTEX_HELD
60 #undef RW_READ_HELD
61 #undef RW_WRITE_HELD
62 
63 #include <fmd_asru.h>
64 #include <fmd_error.h>
65 #include <fmd_event.h>
66 #include <fmd_fmri.h>
67 #include <fmd_module.h>
68 #include <fmd_subr.h>
69 #include <fmd_topo.h>
70 #include <fmd.h>
71 
72 void
73 fmd_dr_event(sysevent_t *sep)
74 {
75 	uint64_t gen;
76 	fmd_event_t *e;
77 	const char *class = sysevent_get_class_name(sep);
78 	const char *subclass = sysevent_get_subclass_name(sep);
79 	hrtime_t evtime;
80 	fmd_topo_t *ftp, *prev;
81 	boolean_t update_topo = B_FALSE;
82 
83 	if (strcmp(class, EC_DR) == 0) {
84 		if (strcmp(subclass, ESC_DR_AP_STATE_CHANGE) != 0 &&
85 		    strcmp(subclass, ESC_DR_TARGET_STATE_CHANGE) != 0)
86 			return;
87 
88 		/*
89 		 * The DR generation is only changed in response to DR events.
90 		 */
91 		update_topo = B_TRUE;
92 
93 		(void) pthread_mutex_lock(&fmd.d_stats_lock);
94 		gen = fmd.d_stats->ds_dr_gen.fmds_value.ui64++;
95 		(void) pthread_mutex_unlock(&fmd.d_stats_lock);
96 
97 		TRACE((FMD_DBG_XPRT, "dr event %p, gen=%llu",
98 		    (void *)sep, gen));
99 	} else if (strcmp(class, EC_DEVFS) == 0) {
100 		/*
101 		 * A devfs configuration event can change the topology,
102 		 * as disk nodes only exist when the device is configured.
103 		 */
104 		update_topo = B_TRUE;
105 	} else if (strcmp(class, EC_PLATFORM) == 0) {
106 		if (strcmp(subclass, ESC_PLATFORM_SP_RESET) == 0) {
107 			/*
108 			 * Since we rely on the SP to enumerate fans,
109 			 * power-supplies and sensors/leds, it would be prudent
110 			 * to take a new snapshot if the SP resets.
111 			 */
112 			update_topo = B_TRUE;
113 		}
114 	} else if (strcmp(class, EC_ZFS) == 0) {
115 		/*
116 		 * These events can change the resource cache.
117 		 */
118 		if (strcmp(subclass, ESC_ZFS_VDEV_CLEAR) != 0 &&
119 		    strcmp(subclass, ESC_ZFS_VDEV_REMOVE) != 0 &&
120 		    strcmp(subclass, ESC_ZFS_POOL_DESTROY) != 0)
121 			return;
122 	} else if (strcmp(class, EC_DEV_ADD) == 0 ||
123 	    strcmp(class, EC_DEV_REMOVE) == 0) {
124 		if (strcmp(subclass, ESC_DISK) != 0)
125 			return;
126 
127 		update_topo = B_TRUE;
128 	}
129 
130 	/*
131 	 * Take a topo snapshot and notify modules of the change.  Picking an
132 	 * accurate time here is difficult.  On one hand, we have the timestamp
133 	 * of the underlying sysevent, indicating when the reconfiguration event
134 	 * occurred.  On the other hand, we are taking the topo snapshot
135 	 * asynchronously, and hence the timestamp of the snapshot is the
136 	 * current time.  Pretending this topo snapshot was valid at the time
137 	 * the sysevent was posted seems wrong, so we instead opt for the
138 	 * current time as an upper bound on the snapshot validity.
139 	 *
140 	 * Along these lines, we keep track of the last time we dispatched a
141 	 * topo snapshot.  If the sysevent occurred before the last topo
142 	 * snapshot, then don't bother dispatching another topo change event.
143 	 * We've already indicated (to the best of our ability) the change in
144 	 * topology.  This prevents endless topo snapshots in response to a
145 	 * flurry of sysevents.
146 	 */
147 	sysevent_get_time(sep, &evtime);
148 	prev = fmd_topo_hold();
149 	if (evtime <= prev->ft_time_begin &&
150 	    fmd.d_clockops == &fmd_timeops_native) {
151 		fmd_topo_rele(prev);
152 		return;
153 	}
154 	fmd_topo_rele(prev);
155 
156 	if (update_topo)
157 		fmd_topo_update(B_FALSE);
158 
159 	ftp = fmd_topo_hold();
160 	e = fmd_event_create(FMD_EVT_TOPO, ftp->ft_time_end, NULL, ftp);
161 	fmd_modhash_dispatch(fmd.d_mod_hash, e);
162 }
163