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 https://opensource.org/licenses/CDDL-1.0.
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 (c) 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
24 */
25
26 #include <sys/zfs_context.h>
27 #include <sys/trace_zfs.h>
28
29 typedef struct zfs_dbgmsg {
30 procfs_list_node_t zdm_node;
31 uint64_t zdm_timestamp;
32 uint_t zdm_size;
33 char zdm_msg[]; /* variable length allocation */
34 } zfs_dbgmsg_t;
35
36 static procfs_list_t zfs_dbgmsgs;
37 static uint_t zfs_dbgmsg_size = 0;
38 static uint_t zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
39
40 /*
41 * Internal ZFS debug messages are enabled by default.
42 *
43 * # Print debug messages
44 * cat /proc/spl/kstat/zfs/dbgmsg
45 *
46 * # Disable the kernel debug message log.
47 * echo 0 > /sys/module/zfs/parameters/zfs_dbgmsg_enable
48 *
49 * # Clear the kernel debug message log.
50 * echo 0 >/proc/spl/kstat/zfs/dbgmsg
51 */
52 int zfs_dbgmsg_enable = B_TRUE;
53
54 static int
zfs_dbgmsg_show_header(struct seq_file * f)55 zfs_dbgmsg_show_header(struct seq_file *f)
56 {
57 seq_printf(f, "%-12s %-8s\n", "timestamp", "message");
58 return (0);
59 }
60
61 static int
zfs_dbgmsg_show(struct seq_file * f,void * p)62 zfs_dbgmsg_show(struct seq_file *f, void *p)
63 {
64 zfs_dbgmsg_t *zdm = (zfs_dbgmsg_t *)p;
65 seq_printf(f, "%-12llu %-s\n",
66 (u_longlong_t)zdm->zdm_timestamp, zdm->zdm_msg);
67 return (0);
68 }
69
70 static void
zfs_dbgmsg_purge(uint_t max_size)71 zfs_dbgmsg_purge(uint_t max_size)
72 {
73 while (zfs_dbgmsg_size > max_size) {
74 zfs_dbgmsg_t *zdm = list_remove_head(&zfs_dbgmsgs.pl_list);
75 if (zdm == NULL)
76 return;
77
78 uint_t size = zdm->zdm_size;
79 kmem_free(zdm, size);
80 zfs_dbgmsg_size -= size;
81 }
82 }
83
84 static int
zfs_dbgmsg_clear(procfs_list_t * procfs_list)85 zfs_dbgmsg_clear(procfs_list_t *procfs_list)
86 {
87 (void) procfs_list;
88 mutex_enter(&zfs_dbgmsgs.pl_lock);
89 zfs_dbgmsg_purge(0);
90 mutex_exit(&zfs_dbgmsgs.pl_lock);
91 return (0);
92 }
93
94 void
zfs_dbgmsg_init(void)95 zfs_dbgmsg_init(void)
96 {
97 procfs_list_install("zfs",
98 NULL,
99 "dbgmsg",
100 0600,
101 &zfs_dbgmsgs,
102 zfs_dbgmsg_show,
103 zfs_dbgmsg_show_header,
104 zfs_dbgmsg_clear,
105 offsetof(zfs_dbgmsg_t, zdm_node));
106 }
107
108 void
zfs_dbgmsg_fini(void)109 zfs_dbgmsg_fini(void)
110 {
111 procfs_list_uninstall(&zfs_dbgmsgs);
112 zfs_dbgmsg_purge(0);
113
114 /*
115 * TODO - decide how to make this permanent
116 */
117 #ifdef _KERNEL
118 procfs_list_destroy(&zfs_dbgmsgs);
119 #endif
120 }
121
122 void
__set_error(const char * file,const char * func,int line,int err)123 __set_error(const char *file, const char *func, int line, int err)
124 {
125 /*
126 * To enable this:
127 *
128 * $ echo 512 >/sys/module/zfs/parameters/zfs_flags
129 */
130 if (zfs_flags & ZFS_DEBUG_SET_ERROR)
131 __dprintf(B_FALSE, file, func, line, "error %lu",
132 (ulong_t)err);
133 }
134
135 void
__zfs_dbgmsg(char * buf)136 __zfs_dbgmsg(char *buf)
137 {
138 uint_t size = sizeof (zfs_dbgmsg_t) + strlen(buf) + 1;
139 zfs_dbgmsg_t *zdm = kmem_zalloc(size, KM_SLEEP);
140 zdm->zdm_size = size;
141 zdm->zdm_timestamp = gethrestime_sec();
142 strcpy(zdm->zdm_msg, buf);
143
144 mutex_enter(&zfs_dbgmsgs.pl_lock);
145 procfs_list_add(&zfs_dbgmsgs, zdm);
146 zfs_dbgmsg_size += size;
147 zfs_dbgmsg_purge(zfs_dbgmsg_maxsize);
148 mutex_exit(&zfs_dbgmsgs.pl_lock);
149 }
150
151 #ifdef _KERNEL
152
153 void
__dprintf(boolean_t dprint,const char * file,const char * func,int line,const char * fmt,...)154 __dprintf(boolean_t dprint, const char *file, const char *func,
155 int line, const char *fmt, ...)
156 {
157 const char *newfile;
158 va_list adx;
159 size_t size;
160 char *buf;
161 char *nl;
162 int i;
163 char *prefix = (dprint) ? "dprintf: " : "";
164
165 size = 1024;
166 buf = kmem_alloc(size, KM_SLEEP);
167
168 /*
169 * Get rid of annoying prefix to filename.
170 */
171 newfile = strrchr(file, '/');
172 if (newfile != NULL) {
173 newfile = newfile + 1; /* Get rid of leading / */
174 } else {
175 newfile = file;
176 }
177
178 i = snprintf(buf, size, "%px %s%s:%d:%s(): ",
179 curthread, prefix, newfile, line, func);
180
181 if (i < size) {
182 va_start(adx, fmt);
183 (void) vsnprintf(buf + i, size - i, fmt, adx);
184 va_end(adx);
185 }
186
187 /*
188 * Get rid of trailing newline for dprintf logs.
189 */
190 if (dprint && buf[0] != '\0') {
191 nl = &buf[strlen(buf) - 1];
192 if (*nl == '\n')
193 *nl = '\0';
194 }
195
196 /*
197 * To get this data enable the zfs__dprintf trace point as shown:
198 *
199 * # Enable zfs__dprintf tracepoint, clear the tracepoint ring buffer
200 * $ echo 1 > /sys/kernel/debug/tracing/events/zfs/enable
201 * $ echo 0 > /sys/kernel/debug/tracing/trace
202 *
203 * # Dump the ring buffer.
204 * $ cat /sys/kernel/debug/tracing/trace
205 */
206 DTRACE_PROBE1(zfs__dprintf, char *, buf);
207
208 /*
209 * To get this data:
210 *
211 * $ cat /proc/spl/kstat/zfs/dbgmsg
212 *
213 * To clear the buffer:
214 * $ echo 0 > /proc/spl/kstat/zfs/dbgmsg
215 */
216 __zfs_dbgmsg(buf);
217
218 kmem_free(buf, size);
219 }
220
221 #else
222
223 void
zfs_dbgmsg_print(int fd,const char * tag)224 zfs_dbgmsg_print(int fd, const char *tag)
225 {
226 ssize_t ret __attribute__((unused));
227
228 mutex_enter(&zfs_dbgmsgs.pl_lock);
229
230 /*
231 * We use write() in this function instead of printf()
232 * so it is safe to call from a signal handler.
233 */
234 ret = write(fd, "ZFS_DBGMSG(", 11);
235 ret = write(fd, tag, strlen(tag));
236 ret = write(fd, ") START:\n", 9);
237
238 for (zfs_dbgmsg_t *zdm = list_head(&zfs_dbgmsgs.pl_list); zdm != NULL;
239 zdm = list_next(&zfs_dbgmsgs.pl_list, zdm)) {
240 ret = write(fd, zdm->zdm_msg, strlen(zdm->zdm_msg));
241 ret = write(fd, "\n", 1);
242 }
243
244 ret = write(fd, "ZFS_DBGMSG(", 11);
245 ret = write(fd, tag, strlen(tag));
246 ret = write(fd, ") END\n", 6);
247
248 mutex_exit(&zfs_dbgmsgs.pl_lock);
249 }
250 #endif /* _KERNEL */
251
252 #ifdef _KERNEL
253 module_param(zfs_dbgmsg_enable, int, 0644);
254 MODULE_PARM_DESC(zfs_dbgmsg_enable, "Enable ZFS debug message log");
255
256 /* BEGIN CSTYLED */
257 module_param(zfs_dbgmsg_maxsize, uint, 0644);
258 /* END CSTYLED */
259 MODULE_PARM_DESC(zfs_dbgmsg_maxsize, "Maximum ZFS debug log size");
260 #endif
261