1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * Copyright (C) 2005 Oracle.  All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public
17  * License along with this program; if not, write to the
18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19  * Boston, MA 021110-1307, USA.
20  */
21 
22 #ifndef O2CLUSTER_MASKLOG_H
23 #define O2CLUSTER_MASKLOG_H
24 
25 /*
26  * For now this is a trivial wrapper around printk() that gives the critical
27  * ability to enable sets of debugging output at run-time.  In the future this
28  * will almost certainly be redirected to relayfs so that it can pay a
29  * substantially lower heisenberg tax.
30  *
31  * Callers associate the message with a bitmask and a global bitmask is
32  * maintained with help from /proc.  If any of the bits match the message is
33  * output.
34  *
35  * We must have efficient bit tests on i386 and it seems gcc still emits crazy
36  * code for the 64bit compare.  It emits very good code for the dual unsigned
37  * long tests, though, completely avoiding tests that can never pass if the
38  * caller gives a constant bitmask that fills one of the longs with all 0s.  So
39  * the desire is to have almost all of the calls decided on by comparing just
40  * one of the longs.  This leads to having infrequently given bits that are
41  * frequently matched in the high bits.
42  *
43  * _ERROR and _NOTICE are used for messages that always go to the console and
44  * have appropriate KERN_ prefixes.  We wrap these in our function instead of
45  * just calling printk() so that this can eventually make its way through
46  * relayfs along with the debugging messages.  Everything else gets KERN_DEBUG.
47  * The inline tests and macro dance give GCC the opportunity to quite cleverly
48  * only emit the appropriage printk() when the caller passes in a constant
49  * mask, as is almost always the case.
50  *
51  * All this bitmask nonsense is managed from the files under
52  * /sys/fs/o2cb/logmask/.  Reading the files gives a straightforward
53  * indication of which bits are allowed (allow) or denied (off/deny).
54  * 	ENTRY deny
55  * 	EXIT deny
56  * 	TCP off
57  * 	MSG off
58  * 	SOCKET off
59  * 	ERROR allow
60  * 	NOTICE allow
61  *
62  * Writing changes the state of a given bit and requires a strictly formatted
63  * single write() call:
64  *
65  * 	write(fd, "allow", 5);
66  *
67  * Echoing allow/deny/off string into the logmask files can flip the bits
68  * on or off as expected; here is the bash script for example:
69  *
70  * log_mask="/sys/fs/o2cb/log_mask"
71  * for node in ENTRY EXIT TCP MSG SOCKET ERROR NOTICE; do
72  *	echo allow >"$log_mask"/"$node"
73  * done
74  *
75  * The debugfs.ocfs2 tool can also flip the bits with the -l option:
76  *
77  * debugfs.ocfs2 -l TCP allow
78  */
79 
80 /* for task_struct */
81 #include <linux/sched.h>
82 
83 /* bits that are frequently given and infrequently matched in the low word */
84 /* NOTE: If you add a flag, you need to also update masklog.c! */
85 #define ML_TCP		0x0000000000000001ULL /* net cluster/tcp.c */
86 #define ML_MSG		0x0000000000000002ULL /* net network messages */
87 #define ML_SOCKET	0x0000000000000004ULL /* net socket lifetime */
88 #define ML_HEARTBEAT	0x0000000000000008ULL /* hb all heartbeat tracking */
89 #define ML_HB_BIO	0x0000000000000010ULL /* hb io tracing */
90 #define ML_DLMFS	0x0000000000000020ULL /* dlm user dlmfs */
91 #define ML_DLM		0x0000000000000040ULL /* dlm general debugging */
92 #define ML_DLM_DOMAIN	0x0000000000000080ULL /* dlm domain debugging */
93 #define ML_DLM_THREAD	0x0000000000000100ULL /* dlm domain thread */
94 #define ML_DLM_MASTER	0x0000000000000200ULL /* dlm master functions */
95 #define ML_DLM_RECOVERY	0x0000000000000400ULL /* dlm master functions */
96 #define ML_DLM_GLUE	0x0000000000000800ULL /* ocfs2 dlm glue layer */
97 #define ML_VOTE		0x0000000000001000ULL /* ocfs2 node messaging  */
98 #define ML_CONN		0x0000000000002000ULL /* net connection management */
99 #define ML_QUORUM	0x0000000000004000ULL /* net connection quorum */
100 #define ML_BASTS	0x0000000000008000ULL /* dlmglue asts and basts */
101 #define ML_CLUSTER	0x0000000000010000ULL /* cluster stack */
102 
103 /* bits that are infrequently given and frequently matched in the high word */
104 #define ML_ERROR	0x1000000000000000ULL /* sent to KERN_ERR */
105 #define ML_NOTICE	0x2000000000000000ULL /* setn to KERN_NOTICE */
106 #define ML_KTHREAD	0x4000000000000000ULL /* kernel thread activity */
107 
108 #define MLOG_INITIAL_AND_MASK (ML_ERROR|ML_NOTICE)
109 #ifndef MLOG_MASK_PREFIX
110 #define MLOG_MASK_PREFIX 0
111 #endif
112 
113 /*
114  * When logging is disabled, force the bit test to 0 for anything other
115  * than errors and notices, allowing gcc to remove the code completely.
116  * When enabled, allow all masks.
117  */
118 #if defined(CONFIG_OCFS2_DEBUG_MASKLOG)
119 #define ML_ALLOWED_BITS ~0
120 #else
121 #define ML_ALLOWED_BITS (ML_ERROR|ML_NOTICE)
122 #endif
123 
124 #define MLOG_MAX_BITS 64
125 
126 struct mlog_bits {
127 	unsigned long words[MLOG_MAX_BITS / BITS_PER_LONG];
128 };
129 
130 extern struct mlog_bits mlog_and_bits, mlog_not_bits;
131 
132 #if BITS_PER_LONG == 32
133 
134 #define __mlog_test_u64(mask, bits)			\
135 	( (u32)(mask & 0xffffffff) & bits.words[0] || 	\
136 	  ((u64)(mask) >> 32) & bits.words[1] )
137 #define __mlog_set_u64(mask, bits) do {			\
138 	bits.words[0] |= (u32)(mask & 0xffffffff);	\
139        	bits.words[1] |= (u64)(mask) >> 32;		\
140 } while (0)
141 #define __mlog_clear_u64(mask, bits) do {		\
142 	bits.words[0] &= ~((u32)(mask & 0xffffffff));	\
143        	bits.words[1] &= ~((u64)(mask) >> 32);		\
144 } while (0)
145 #define MLOG_BITS_RHS(mask) {				\
146 	{						\
147 		[0] = (u32)(mask & 0xffffffff),		\
148 		[1] = (u64)(mask) >> 32,		\
149 	}						\
150 }
151 
152 #else /* 32bit long above, 64bit long below */
153 
154 #define __mlog_test_u64(mask, bits)	((mask) & bits.words[0])
155 #define __mlog_set_u64(mask, bits) do {		\
156 	bits.words[0] |= (mask);		\
157 } while (0)
158 #define __mlog_clear_u64(mask, bits) do {	\
159 	bits.words[0] &= ~(mask);		\
160 } while (0)
161 #define MLOG_BITS_RHS(mask) { { (mask) } }
162 
163 #endif
164 
165 __printf(4, 5)
166 void __mlog_printk(const u64 *m, const char *func, int line,
167 		   const char *fmt, ...);
168 
169 /*
170  * Testing before the __mlog_printk call lets the compiler eliminate the
171  * call completely when (m & ML_ALLOWED_BITS) is 0.
172  */
173 #define mlog(mask, fmt, ...)						\
174 do {									\
175 	u64 _m = MLOG_MASK_PREFIX | (mask);				\
176 	if (_m & ML_ALLOWED_BITS)					\
177 		__mlog_printk(&_m, __func__, __LINE__, fmt,		\
178 			      ##__VA_ARGS__);				\
179 } while (0)
180 
181 #define mlog_ratelimited(mask, fmt, ...)				\
182 do {									\
183 	static DEFINE_RATELIMIT_STATE(_rs,				\
184 				      DEFAULT_RATELIMIT_INTERVAL,	\
185 				      DEFAULT_RATELIMIT_BURST);		\
186 	if (__ratelimit(&_rs))						\
187 		mlog(mask, fmt, ##__VA_ARGS__);				\
188 } while (0)
189 
190 #define mlog_errno(st) ({						\
191 	int _st = (st);							\
192 	if (_st != -ERESTARTSYS && _st != -EINTR &&			\
193 	    _st != AOP_TRUNCATED_PAGE && _st != -ENOSPC &&		\
194 	    _st != -EDQUOT)						\
195 		mlog(ML_ERROR, "status = %lld\n", (long long)_st);	\
196 	_st;								\
197 })
198 
199 #define mlog_bug_on_msg(cond, fmt, args...) do {			\
200 	if (cond) {							\
201 		mlog(ML_ERROR, "bug expression: " #cond "\n");		\
202 		mlog(ML_ERROR, fmt, ##args);				\
203 		BUG();							\
204 	}								\
205 } while (0)
206 
207 #include <linux/kobject.h>
208 #include <linux/sysfs.h>
209 int mlog_sys_init(struct kset *o2cb_subsys);
210 void mlog_sys_shutdown(void);
211 
212 #endif /* O2CLUSTER_MASKLOG_H */
213