1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * CDDL HEADER START
4 *
5 * The contents of this file are subject to the terms of the
6 * Common Development and Distribution License (the "License").
7 * You may not use this file except in compliance with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or https://opensource.org/licenses/CDDL-1.0.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
25 */
26
27 #include <sys/zfs_context.h>
28 #include <sys/trace_zfs.h>
29
30 typedef struct zfs_dbgmsg {
31 procfs_list_node_t zdm_node;
32 uint64_t zdm_timestamp;
33 uint_t zdm_size;
34 char zdm_msg[]; /* variable length allocation */
35 } zfs_dbgmsg_t;
36
37 static procfs_list_t zfs_dbgmsgs;
38 static uint_t zfs_dbgmsg_size = 0;
39 static uint_t zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
40
41 /*
42 * Internal ZFS debug messages are enabled by default.
43 *
44 * # Print debug messages
45 * cat /proc/spl/kstat/zfs/dbgmsg
46 *
47 * # Disable the kernel debug message log.
48 * echo 0 > /sys/module/zfs/parameters/zfs_dbgmsg_enable
49 *
50 * # Clear the kernel debug message log.
51 * echo 0 >/proc/spl/kstat/zfs/dbgmsg
52 */
53 int zfs_dbgmsg_enable = B_TRUE;
54
55 static int
zfs_dbgmsg_show_header(struct seq_file * f)56 zfs_dbgmsg_show_header(struct seq_file *f)
57 {
58 seq_printf(f, "%-12s %-8s\n", "timestamp", "message");
59 return (0);
60 }
61
62 static int
zfs_dbgmsg_show(struct seq_file * f,void * p)63 zfs_dbgmsg_show(struct seq_file *f, void *p)
64 {
65 zfs_dbgmsg_t *zdm = (zfs_dbgmsg_t *)p;
66 seq_printf(f, "%-12llu %-s\n",
67 (u_longlong_t)zdm->zdm_timestamp, zdm->zdm_msg);
68 return (0);
69 }
70
71 static void
zfs_dbgmsg_purge(uint_t max_size)72 zfs_dbgmsg_purge(uint_t max_size)
73 {
74 while (zfs_dbgmsg_size > max_size) {
75 zfs_dbgmsg_t *zdm = list_remove_head(&zfs_dbgmsgs.pl_list);
76 if (zdm == NULL)
77 return;
78
79 uint_t size = zdm->zdm_size;
80 kmem_free(zdm, size);
81 zfs_dbgmsg_size -= size;
82 }
83 }
84
85 static int
zfs_dbgmsg_clear(procfs_list_t * procfs_list)86 zfs_dbgmsg_clear(procfs_list_t *procfs_list)
87 {
88 (void) procfs_list;
89 mutex_enter(&zfs_dbgmsgs.pl_lock);
90 zfs_dbgmsg_purge(0);
91 mutex_exit(&zfs_dbgmsgs.pl_lock);
92 return (0);
93 }
94
95 void
zfs_dbgmsg_init(void)96 zfs_dbgmsg_init(void)
97 {
98 procfs_list_install("zfs",
99 NULL,
100 "dbgmsg",
101 0600,
102 &zfs_dbgmsgs,
103 zfs_dbgmsg_show,
104 zfs_dbgmsg_show_header,
105 zfs_dbgmsg_clear,
106 offsetof(zfs_dbgmsg_t, zdm_node));
107 }
108
109 void
zfs_dbgmsg_fini(void)110 zfs_dbgmsg_fini(void)
111 {
112 procfs_list_uninstall(&zfs_dbgmsgs);
113 zfs_dbgmsg_purge(0);
114
115 procfs_list_destroy(&zfs_dbgmsgs);
116 }
117
118 void
__set_error(const char * file,const char * func,int line,int err)119 __set_error(const char *file, const char *func, int line, int err)
120 {
121 /*
122 * To enable this:
123 *
124 * $ echo 512 >/sys/module/zfs/parameters/zfs_flags
125 */
126 if (zfs_flags & ZFS_DEBUG_SET_ERROR)
127 __dprintf(B_FALSE, file, func, line, "error %lu",
128 (ulong_t)err);
129 }
130
131 void
__zfs_dbgmsg(char * buf)132 __zfs_dbgmsg(char *buf)
133 {
134 uint_t size = sizeof (zfs_dbgmsg_t) + strlen(buf) + 1;
135 zfs_dbgmsg_t *zdm = kmem_zalloc(size, KM_SLEEP);
136 zdm->zdm_size = size;
137 zdm->zdm_timestamp = gethrestime_sec();
138 strcpy(zdm->zdm_msg, buf);
139
140 mutex_enter(&zfs_dbgmsgs.pl_lock);
141 procfs_list_add(&zfs_dbgmsgs, zdm);
142 zfs_dbgmsg_size += size;
143 zfs_dbgmsg_purge(zfs_dbgmsg_maxsize);
144 mutex_exit(&zfs_dbgmsgs.pl_lock);
145 }
146
147 void
__dprintf(boolean_t dprint,const char * file,const char * func,int line,const char * fmt,...)148 __dprintf(boolean_t dprint, const char *file, const char *func,
149 int line, const char *fmt, ...)
150 {
151 const char *newfile;
152 va_list adx;
153 size_t size;
154 char *buf;
155 char *nl;
156 int i;
157 char *prefix = (dprint) ? "dprintf: " : "";
158
159 size = 1024;
160 buf = kmem_alloc(size, KM_SLEEP);
161
162 /*
163 * Get rid of annoying prefix to filename.
164 */
165 newfile = strrchr(file, '/');
166 if (newfile != NULL) {
167 newfile = newfile + 1; /* Get rid of leading / */
168 } else {
169 newfile = file;
170 }
171
172 i = snprintf(buf, size, "%px %s%s:%d:%s(): ",
173 curthread, prefix, newfile, line, func);
174
175 if (i < size) {
176 va_start(adx, fmt);
177 (void) vsnprintf(buf + i, size - i, fmt, adx);
178 va_end(adx);
179 }
180
181 /*
182 * Get rid of trailing newline for dprintf logs.
183 */
184 if (dprint && buf[0] != '\0') {
185 nl = &buf[strlen(buf) - 1];
186 if (*nl == '\n')
187 *nl = '\0';
188 }
189
190 /*
191 * To get this data enable the zfs__dprintf trace point as shown:
192 *
193 * # Enable zfs__dprintf tracepoint, clear the tracepoint ring buffer
194 * $ echo 1 > /sys/kernel/debug/tracing/events/zfs/enable
195 * $ echo 0 > /sys/kernel/debug/tracing/trace
196 *
197 * # Dump the ring buffer.
198 * $ cat /sys/kernel/debug/tracing/trace
199 */
200 DTRACE_PROBE1(zfs__dprintf, char *, buf);
201
202 /*
203 * To get this data:
204 *
205 * $ cat /proc/spl/kstat/zfs/dbgmsg
206 *
207 * To clear the buffer:
208 * $ echo 0 > /proc/spl/kstat/zfs/dbgmsg
209 */
210 __zfs_dbgmsg(buf);
211
212 kmem_free(buf, size);
213 }
214
215 module_param(zfs_dbgmsg_enable, int, 0644);
216 MODULE_PARM_DESC(zfs_dbgmsg_enable, "Enable ZFS debug message log");
217
218 module_param(zfs_dbgmsg_maxsize, uint, 0644);
219 MODULE_PARM_DESC(zfs_dbgmsg_maxsize, "Maximum ZFS debug log size");
220