drivers/staging/lustre/lnet/libcfs/fail.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see http://www.gnu.org/licenses
  18  *
  19  * GPL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Use is subject to license terms.
  24  *
  25  * Copyright (c) 2011, 2015, Intel Corporation.
  26  */
  27 /*
  28  * This file is part of Lustre, http://www.lustre.org/
  29  * Lustre is a trademark of Oracle Corporation, Inc.
  30  */
  31
  32 #include "../../include/linux/libcfs/libcfs.h"
  33
  34 unsigned long cfs_fail_loc;
  35 EXPORT_SYMBOL(cfs_fail_loc);
  36
  37 unsigned int cfs_fail_val;
  38 EXPORT_SYMBOL(cfs_fail_val);
  39
  40 int cfs_fail_err;
  41 EXPORT_SYMBOL(cfs_fail_err);
  42
  43 DECLARE_WAIT_QUEUE_HEAD(cfs_race_waitq);
  44 EXPORT_SYMBOL(cfs_race_waitq);
  45
  46 int cfs_race_state;
  47 EXPORT_SYMBOL(cfs_race_state);
  48
  49 int __cfs_fail_check_set(__u32 id, __u32 value, int set)
  50 {
  51         static atomic_t cfs_fail_count = ATOMIC_INIT(0);
  52
  53         LASSERT(!(id & CFS_FAIL_ONCE));
  54
  55         if ((cfs_fail_loc & (CFS_FAILED | CFS_FAIL_ONCE)) ==
  56             (CFS_FAILED | CFS_FAIL_ONCE)) {
  57                 atomic_set(&cfs_fail_count, 0); /* paranoia */
  58                 return 0;
  59         }
  60
  61         /* Fail 1/cfs_fail_val times */
  62         if (cfs_fail_loc & CFS_FAIL_RAND) {
  63                 if (cfs_fail_val < 2 || cfs_rand() % cfs_fail_val > 0)
  64                         return 0;
  65         }
  66
  67         /* Skip the first cfs_fail_val, then fail */
  68         if (cfs_fail_loc & CFS_FAIL_SKIP) {
  69                 if (atomic_inc_return(&cfs_fail_count) <= cfs_fail_val)
  70                         return 0;
  71         }
  72
  73         /* check cfs_fail_val... */
  74         if (set == CFS_FAIL_LOC_VALUE) {
  75                 if (cfs_fail_val != -1 && cfs_fail_val != value)
  76                         return 0;
  77         }
  78
  79         /* Fail cfs_fail_val times, overridden by FAIL_ONCE */
  80         if (cfs_fail_loc & CFS_FAIL_SOME &&
  81             (!(cfs_fail_loc & CFS_FAIL_ONCE) || cfs_fail_val <= 1)) {
  82                 int count = atomic_inc_return(&cfs_fail_count);
  83
  84                 if (count >= cfs_fail_val) {
  85                         set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  86                         atomic_set(&cfs_fail_count, 0);
  87                         /* we are lost race to increase  */
  88                         if (count > cfs_fail_val)
  89                                 return 0;
  90                 }
  91         }
  92
  93         if ((set == CFS_FAIL_LOC_ORSET || set == CFS_FAIL_LOC_RESET) &&
  94             (value & CFS_FAIL_ONCE))
  95                 set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  96         /* Lost race to set CFS_FAILED_BIT. */
  97         if (test_and_set_bit(CFS_FAILED_BIT, &cfs_fail_loc)) {
  98                 /* If CFS_FAIL_ONCE is valid, only one process can fail,
  99                  * otherwise multi-process can fail at the same time.
 100                  */
 101                 if (cfs_fail_loc & CFS_FAIL_ONCE)
 102                         return 0;
 103         }
 104
 105         switch (set) {
 106         case CFS_FAIL_LOC_NOSET:
 107         case CFS_FAIL_LOC_VALUE:
 108                 break;
 109         case CFS_FAIL_LOC_ORSET:
 110                 cfs_fail_loc |= value & ~(CFS_FAILED | CFS_FAIL_ONCE);
 111                 break;
 112         case CFS_FAIL_LOC_RESET:
 113                 cfs_fail_loc = value;
 114                 break;
 115         default:
 116                 LASSERTF(0, "called with bad set %u\n", set);
 117                 break;
 118         }
 119
 120         return 1;
 121 }
 122 EXPORT_SYMBOL(__cfs_fail_check_set);
 123
 124 int __cfs_fail_timeout_set(__u32 id, __u32 value, int ms, int set)
 125 {
 126         int ret;
 127
 128         ret = __cfs_fail_check_set(id, value, set);
 129         if (ret && likely(ms > 0)) {
 130                 CERROR("cfs_fail_timeout id %x sleeping for %dms\n",
 131                        id, ms);
 132                 set_current_state(TASK_UNINTERRUPTIBLE);
 133                 schedule_timeout(cfs_time_seconds(ms) / 1000);
 134                 CERROR("cfs_fail_timeout id %x awake\n", id);
 135         }
 136         return ret;
 137 }
 138 EXPORT_SYMBOL(__cfs_fail_timeout_set);