summaryrefslogtreecommitdiffstats
path: root/module/zfs/zfs_debug.c
blob: 55a18e8399b4c12846eceef03200ab2a17bfd3de (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2013 by Delphix. All rights reserved.
 */

#include <sys/zfs_context.h>

#if !defined(_KERNEL) || !defined(__linux__)
list_t zfs_dbgmsgs;
int zfs_dbgmsg_size;
kmutex_t zfs_dbgmsgs_lock;
int zfs_dbgmsg_maxsize = 1<<20; /* 1MB */
#endif

/*
 * Enable various debugging features.
 */
int zfs_flags = 0;

/*
 * zfs_recover can be set to nonzero to attempt to recover from
 * otherwise-fatal errors, typically caused by on-disk corruption.  When
 * set, calls to zfs_panic_recover() will turn into warning messages.
 * This should only be used as a last resort, as it typically results
 * in leaked space, or worse.
 */
int zfs_recover = 0;


void
zfs_panic_recover(const char *fmt, ...)
{
	va_list adx;

	va_start(adx, fmt);
	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
	va_end(adx);
}

/*
 * Debug logging is enabled by default for production kernel builds.
 * The overhead for this is negligible and the logs can be valuable when
 * debugging.  For non-production user space builds all debugging except
 * logging is enabled since performance is no longer a concern.
 */
void
zfs_dbgmsg_init(void)
{
#if !defined(_KERNEL) || !defined(__linux__)
	list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
	    offsetof(zfs_dbgmsg_t, zdm_node));
	mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
#endif

	if (zfs_flags == 0) {
#if defined(_KERNEL)
		zfs_flags = ZFS_DEBUG_DPRINTF;
		spl_debug_set_mask(spl_debug_get_mask() | SD_DPRINTF);
		spl_debug_set_subsys(spl_debug_get_subsys() | SS_USER1);
#else
		zfs_flags = ~ZFS_DEBUG_DPRINTF;
#endif /* _KERNEL */
	}
}

void
zfs_dbgmsg_fini(void)
{
#if !defined(_KERNEL) || !defined(__linux__)
	zfs_dbgmsg_t *zdm;

	while ((zdm = list_remove_head(&zfs_dbgmsgs)) != NULL) {
		int size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
		kmem_free(zdm, size);
		zfs_dbgmsg_size -= size;
	}
	mutex_destroy(&zfs_dbgmsgs_lock);
	ASSERT0(zfs_dbgmsg_size);
#endif
	return;
}

#if !defined(_KERNEL) || !defined(__linux__)
/*
 * Print these messages by running:
 * echo ::zfs_dbgmsg | mdb -k
 *
 * Monitor these messages by running:
 * 	dtrace -q -n 'zfs-dbgmsg{printf("%s\n", stringof(arg0))}'
 */
void
zfs_dbgmsg(const char *fmt, ...)
{
	int size;
	va_list adx;
	zfs_dbgmsg_t *zdm;

	va_start(adx, fmt);
	size = vsnprintf(NULL, 0, fmt, adx);
	va_end(adx);

	/*
	 * There is one byte of string in sizeof (zfs_dbgmsg_t), used
	 * for the terminating null.
	 */
	zdm = kmem_alloc(sizeof (zfs_dbgmsg_t) + size, KM_SLEEP);
	zdm->zdm_timestamp = gethrestime_sec();

	va_start(adx, fmt);
	(void) vsnprintf(zdm->zdm_msg, size + 1, fmt, adx);
	va_end(adx);

	DTRACE_PROBE1(zfs__dbgmsg, char *, zdm->zdm_msg);

	mutex_enter(&zfs_dbgmsgs_lock);
	list_insert_tail(&zfs_dbgmsgs, zdm);
	zfs_dbgmsg_size += sizeof (zfs_dbgmsg_t) + size;
	while (zfs_dbgmsg_size > zfs_dbgmsg_maxsize) {
		zdm = list_remove_head(&zfs_dbgmsgs);
		size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
		kmem_free(zdm, size);
		zfs_dbgmsg_size -= size;
	}
	mutex_exit(&zfs_dbgmsgs_lock);
}

void
zfs_dbgmsg_print(const char *tag)
{
	zfs_dbgmsg_t *zdm;

	(void) printf("ZFS_DBGMSG(%s):\n", tag);
	mutex_enter(&zfs_dbgmsgs_lock);
	for (zdm = list_head(&zfs_dbgmsgs); zdm;
	    zdm = list_next(&zfs_dbgmsgs, zdm))
		(void) printf("%s\n", zdm->zdm_msg);
	mutex_exit(&zfs_dbgmsgs_lock);
}
#endif

#if defined(_KERNEL)
module_param(zfs_flags, int, 0644);
MODULE_PARM_DESC(zfs_flags, "Set additional debugging flags");

module_param(zfs_recover, int, 0644);
MODULE_PARM_DESC(zfs_recover, "Set to attempt to recover from fatal errors");
#endif /* _KERNEL */