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 appropriate 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