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