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