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 */ 199