1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* -*- mode: c; c-basic-offset: 8; -*-
3 * vim: noexpandtab sw=8 ts=8 sts=0:
4 *
5 * Copyright (C) 2005 Oracle. All rights reserved.
6 */
7
8 #ifndef O2CLUSTER_MASKLOG_H
9 #define O2CLUSTER_MASKLOG_H
10
11 /*
12 * For now this is a trivial wrapper around printk() that gives the critical
13 * ability to enable sets of debugging output at run-time. In the future this
14 * will almost certainly be redirected to relayfs so that it can pay a
15 * substantially lower heisenberg tax.
16 *
17 * Callers associate the message with a bitmask and a global bitmask is
18 * maintained with help from /proc. If any of the bits match the message is
19 * output.
20 *
21 * We must have efficient bit tests on i386 and it seems gcc still emits crazy
22 * code for the 64bit compare. It emits very good code for the dual unsigned
23 * long tests, though, completely avoiding tests that can never pass if the
24 * caller gives a constant bitmask that fills one of the longs with all 0s. So
25 * the desire is to have almost all of the calls decided on by comparing just
26 * one of the longs. This leads to having infrequently given bits that are
27 * frequently matched in the high bits.
28 *
29 * _ERROR and _NOTICE are used for messages that always go to the console and
30 * have appropriate KERN_ prefixes. We wrap these in our function instead of
31 * just calling printk() so that this can eventually make its way through
32 * relayfs along with the debugging messages. Everything else gets KERN_DEBUG.
33 * The inline tests and macro dance give GCC the opportunity to quite cleverly
34 * only emit the appropriage printk() when the caller passes in a constant
35 * mask, as is almost always the case.
36 *
37 * All this bitmask nonsense is managed from the files under
38 * /sys/fs/o2cb/logmask/. Reading the files gives a straightforward
39 * indication of which bits are allowed (allow) or denied (off/deny).
40 * ENTRY deny
41 * EXIT deny
42 * TCP off
43 * MSG off
44 * SOCKET off
45 * ERROR allow
46 * NOTICE allow
47 *
48 * Writing changes the state of a given bit and requires a strictly formatted
49 * single write() call:
50 *
51 * write(fd, "allow", 5);
52 *
53 * Echoing allow/deny/off string into the logmask files can flip the bits
54 * on or off as expected; here is the bash script for example:
55 *
56 * log_mask="/sys/fs/o2cb/log_mask"
57 * for node in ENTRY EXIT TCP MSG SOCKET ERROR NOTICE; do
58 * echo allow >"$log_mask"/"$node"
59 * done
60 *
61 * The debugfs.ocfs2 tool can also flip the bits with the -l option:
62 *
63 * debugfs.ocfs2 -l TCP allow
64 */
65
66 /* for task_struct */
67 #include <linux/sched.h>
68
69 /* bits that are frequently given and infrequently matched in the low word */
70 /* NOTE: If you add a flag, you need to also update masklog.c! */
71 #define ML_TCP 0x0000000000000001ULL /* net cluster/tcp.c */
72 #define ML_MSG 0x0000000000000002ULL /* net network messages */
73 #define ML_SOCKET 0x0000000000000004ULL /* net socket lifetime */
74 #define ML_HEARTBEAT 0x0000000000000008ULL /* hb all heartbeat tracking */
75 #define ML_HB_BIO 0x0000000000000010ULL /* hb io tracing */
76 #define ML_DLMFS 0x0000000000000020ULL /* dlm user dlmfs */
77 #define ML_DLM 0x0000000000000040ULL /* dlm general debugging */
78 #define ML_DLM_DOMAIN 0x0000000000000080ULL /* dlm domain debugging */
79 #define ML_DLM_THREAD 0x0000000000000100ULL /* dlm domain thread */
80 #define ML_DLM_MASTER 0x0000000000000200ULL /* dlm master functions */
81 #define ML_DLM_RECOVERY 0x0000000000000400ULL /* dlm master functions */
82 #define ML_DLM_GLUE 0x0000000000000800ULL /* ocfs2 dlm glue layer */
83 #define ML_VOTE 0x0000000000001000ULL /* ocfs2 node messaging */
84 #define ML_CONN 0x0000000000002000ULL /* net connection management */
85 #define ML_QUORUM 0x0000000000004000ULL /* net connection quorum */
86 #define ML_BASTS 0x0000000000008000ULL /* dlmglue asts and basts */
87 #define ML_CLUSTER 0x0000000000010000ULL /* cluster stack */
88
89 /* bits that are infrequently given and frequently matched in the high word */
90 #define ML_ERROR 0x1000000000000000ULL /* sent to KERN_ERR */
91 #define ML_NOTICE 0x2000000000000000ULL /* setn to KERN_NOTICE */
92 #define ML_KTHREAD 0x4000000000000000ULL /* kernel thread activity */
93
94 #define MLOG_INITIAL_AND_MASK (ML_ERROR|ML_NOTICE)
95 #ifndef MLOG_MASK_PREFIX
96 #define MLOG_MASK_PREFIX 0
97 #endif
98
99 /*
100 * When logging is disabled, force the bit test to 0 for anything other
101 * than errors and notices, allowing gcc to remove the code completely.
102 * When enabled, allow all masks.
103 */
104 #if defined(CONFIG_OCFS2_DEBUG_MASKLOG)
105 #define ML_ALLOWED_BITS ~0
106 #else
107 #define ML_ALLOWED_BITS (ML_ERROR|ML_NOTICE)
108 #endif
109
110 #define MLOG_MAX_BITS 64
111
112 struct mlog_bits {
113 unsigned long words[MLOG_MAX_BITS / BITS_PER_LONG];
114 };
115
116 extern struct mlog_bits mlog_and_bits, mlog_not_bits;
117
118 #if BITS_PER_LONG == 32
119
120 #define __mlog_test_u64(mask, bits) \
121 ( (u32)(mask & 0xffffffff) & bits.words[0] || \
122 ((u64)(mask) >> 32) & bits.words[1] )
123 #define __mlog_set_u64(mask, bits) do { \
124 bits.words[0] |= (u32)(mask & 0xffffffff); \
125 bits.words[1] |= (u64)(mask) >> 32; \
126 } while (0)
127 #define __mlog_clear_u64(mask, bits) do { \
128 bits.words[0] &= ~((u32)(mask & 0xffffffff)); \
129 bits.words[1] &= ~((u64)(mask) >> 32); \
130 } while (0)
131 #define MLOG_BITS_RHS(mask) { \
132 { \
133 [0] = (u32)(mask & 0xffffffff), \
134 [1] = (u64)(mask) >> 32, \
135 } \
136 }
137
138 #else /* 32bit long above, 64bit long below */
139
140 #define __mlog_test_u64(mask, bits) ((mask) & bits.words[0])
141 #define __mlog_set_u64(mask, bits) do { \
142 bits.words[0] |= (mask); \
143 } while (0)
144 #define __mlog_clear_u64(mask, bits) do { \
145 bits.words[0] &= ~(mask); \
146 } while (0)
147 #define MLOG_BITS_RHS(mask) { { (mask) } }
148
149 #endif
150
151 __printf(4, 5)
152 void __mlog_printk(const u64 *m, const char *func, int line,
153 const char *fmt, ...);
154
155 /*
156 * Testing before the __mlog_printk call lets the compiler eliminate the
157 * call completely when (m & ML_ALLOWED_BITS) is 0.
158 */
159 #define mlog(mask, fmt, ...) \
160 do { \
161 u64 _m = MLOG_MASK_PREFIX | (mask); \
162 if (_m & ML_ALLOWED_BITS) \
163 __mlog_printk(&_m, __func__, __LINE__, fmt, \
164 ##__VA_ARGS__); \
165 } while (0)
166
167 #define mlog_ratelimited(mask, fmt, ...) \
168 do { \
169 static DEFINE_RATELIMIT_STATE(_rs, \
170 DEFAULT_RATELIMIT_INTERVAL, \
171 DEFAULT_RATELIMIT_BURST); \
172 if (__ratelimit(&_rs)) \
173 mlog(mask, fmt, ##__VA_ARGS__); \
174 } while (0)
175
176 #define mlog_errno(st) ({ \
177 int _st = (st); \
178 if (_st != -ERESTARTSYS && _st != -EINTR && \
179 _st != AOP_TRUNCATED_PAGE && _st != -ENOSPC && \
180 _st != -EDQUOT) \
181 mlog(ML_ERROR, "status = %lld\n", (long long)_st); \
182 _st; \
183 })
184
185 #define mlog_bug_on_msg(cond, fmt, args...) do { \
186 if (cond) { \
187 mlog(ML_ERROR, "bug expression: " #cond "\n"); \
188 mlog(ML_ERROR, fmt, ##args); \
189 BUG(); \
190 } \
191 } while (0)
192
193 #include <linux/kobject.h>
194 #include <linux/sysfs.h>
195 int mlog_sys_init(struct kset *o2cb_subsys);
196 void mlog_sys_shutdown(void);
197
198 #endif /* O2CLUSTER_MASKLOG_H */