libcfs/libcfs/fail.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see http://www.gnu.org/licenses
  20  *
  21  * Please contact Oracle Corporation, Inc., 500 Oracle Parkway, Redwood Shores,
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  24  *
  25  * GPL HEADER END
  26  */
  27 /*
  28  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  29  * Use is subject to license terms.
  30  */
  31 /*
  32  * This file is part of Lustre, http://www.lustre.org/
  33  * Lustre is a trademark of Oracle Corporation, Inc.
  34  */
  35
  36 #ifndef __KERNEL__
  37 #include <liblustre.h>
  38 #else
  39 #include <libcfs/libcfs.h>
  40 #endif
  41
  42 unsigned long cfs_fail_loc = 0;
  43 unsigned int cfs_fail_val = 0;
  44 cfs_waitq_t cfs_race_waitq;
  45 int cfs_race_state;
  46
  47 CFS_EXPORT_SYMBOL(cfs_fail_loc);
  48 CFS_EXPORT_SYMBOL(cfs_fail_val);
  49 CFS_EXPORT_SYMBOL(cfs_race_waitq);
  50 CFS_EXPORT_SYMBOL(cfs_race_state);
  51
  52 int __cfs_fail_check_set(__u32 id, __u32 value, int set)
  53 {
  54         static cfs_atomic_t cfs_fail_count = CFS_ATOMIC_INIT(0);
  55
  56         LASSERT(!(id & CFS_FAIL_ONCE));
  57
  58         if ((cfs_fail_loc & (CFS_FAILED | CFS_FAIL_ONCE)) ==
  59             (CFS_FAILED | CFS_FAIL_ONCE)) {
  60                 cfs_atomic_set(&cfs_fail_count, 0); /* paranoia */
  61                 return 0;
  62         }
  63
  64         /* Fail 1/cfs_fail_val times */
  65         if (cfs_fail_loc & CFS_FAIL_RAND) {
  66                 if (cfs_fail_val < 2 || cfs_rand() % cfs_fail_val > 0)
  67                         return 0;
  68         }
  69
  70         /* Skip the first cfs_fail_val, then fail */
  71         if (cfs_fail_loc & CFS_FAIL_SKIP) {
  72                 if (cfs_atomic_inc_return(&cfs_fail_count) <= cfs_fail_val)
  73                         return 0;
  74         }
  75
  76         /* Fail cfs_fail_val times, overridden by FAIL_ONCE */
  77         if (cfs_fail_loc & CFS_FAIL_SOME &&
  78             (!(cfs_fail_loc & CFS_FAIL_ONCE) || cfs_fail_val <= 1)) {
  79                 int count = cfs_atomic_inc_return(&cfs_fail_count);
  80
  81                 if (count >= cfs_fail_val) {
  82                         cfs_set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  83                         cfs_atomic_set(&cfs_fail_count, 0);
  84                         /* we are lost race to increase  */
  85                         if (count > cfs_fail_val)
  86                                 return 0;
  87                 }
  88         }
  89
  90         if ((set == CFS_FAIL_LOC_ORSET || set == CFS_FAIL_LOC_RESET) &&
  91             (value & CFS_FAIL_ONCE))
  92                 cfs_set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  93         /* Lost race to set CFS_FAILED_BIT. */
  94         if (cfs_test_and_set_bit(CFS_FAILED_BIT, &cfs_fail_loc)) {
  95                 /* If CFS_FAIL_ONCE is valid, only one process can fail,
  96                  * otherwise multi-process can fail at the same time. */
  97                 if (cfs_fail_loc & CFS_FAIL_ONCE)
  98                         return 0;
  99         }
 100
 101         switch (set) {
 102                 case CFS_FAIL_LOC_NOSET:
 103                         break;
 104                 case CFS_FAIL_LOC_ORSET:
 105                         cfs_fail_loc |= value & ~(CFS_FAILED | CFS_FAIL_ONCE);
 106                         break;
 107                 case CFS_FAIL_LOC_RESET:
 108                         cfs_fail_loc = value;
 109                         break;
 110                 default:
 111                         LASSERTF(0, "called with bad set %u\n", set);
 112                         break;
 113         }
 114
 115         return 1;
 116 }
 117 CFS_EXPORT_SYMBOL(__cfs_fail_check_set);
 118
 119 int __cfs_fail_timeout_set(__u32 id, __u32 value, int ms, int set)
 120 {
 121         int ret = 0;
 122
 123         ret = __cfs_fail_check_set(id, value, set);
 124         if (ret) {
 125                 CERROR("cfs_fail_timeout id %x sleeping for %dms\n",
 126                        id, ms);
 127                 cfs_schedule_timeout_and_set_state(CFS_TASK_UNINT,
 128                                                    cfs_time_seconds(ms) / 1000);
 129                 cfs_set_current_state(CFS_TASK_RUNNING);
 130                 CERROR("cfs_fail_timeout id %x awake\n", id);
 131         }
 132         return ret;
 133 }
 134 CFS_EXPORT_SYMBOL(__cfs_fail_timeout_set);