fs/ocfs2/cluster/masklog.h

   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_errno(st) ({                                               \
 182         int _st = (st);                                                 \
 183         if (_st != -ERESTARTSYS && _st != -EINTR &&                     \
 184             _st != AOP_TRUNCATED_PAGE && _st != -ENOSPC &&              \
 185             _st != -EDQUOT)                                             \
 186                 mlog(ML_ERROR, "status = %lld\n", (long long)_st);      \
 187         _st;                                                            \
 188 })
 189
 190 #define mlog_bug_on_msg(cond, fmt, args...) do {                        \
 191         if (cond) {                                                     \
 192                 mlog(ML_ERROR, "bug expression: " #cond "\n");          \
 193                 mlog(ML_ERROR, fmt, ##args);                            \
 194                 BUG();                                                  \
 195         }                                                               \
 196 } while (0)
 197
 198 #include <linux/kobject.h>
 199 #include <linux/sysfs.h>
 200 int mlog_sys_init(struct kset *o2cb_subsys);
 201 void mlog_sys_shutdown(void);
 202
 203 #endif /* O2CLUSTER_MASKLOG_H */