LXR linux/drivers/staging/lustre/lustre/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 * Please contact Oracle Corporation, Inc., 500 Oracle Parkway, Redwood Shores,
  20 * CA 94065 USA or visit www.oracle.com if you need additional information or
  21 * have any questions.
  22 *
  23 * GPL HEADER END
  24 */
  25/*
  26 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  27 * Use is subject to license terms.
  28 *
  29 * Copyright (c) 2011, 2012, Intel Corporation.
  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#include "../../include/linux/libcfs/libcfs.h"
  37
  38unsigned long cfs_fail_loc = 0;
  39EXPORT_SYMBOL(cfs_fail_loc);
  40
  41unsigned int cfs_fail_val = 0;
  42EXPORT_SYMBOL(cfs_fail_val);
  43
  44wait_queue_head_t cfs_race_waitq;
  45EXPORT_SYMBOL(cfs_race_waitq);
  46
  47int cfs_race_state;
  48EXPORT_SYMBOL(cfs_race_state);
  49
  50int __cfs_fail_check_set(__u32 id, __u32 value, int set)
  51{
  52        static atomic_t cfs_fail_count = ATOMIC_INIT(0);
  53
  54        LASSERT(!(id & CFS_FAIL_ONCE));
  55
  56        if ((cfs_fail_loc & (CFS_FAILED | CFS_FAIL_ONCE)) ==
  57            (CFS_FAILED | CFS_FAIL_ONCE)) {
  58                atomic_set(&cfs_fail_count, 0); /* paranoia */
  59                return 0;
  60        }
  61
  62        /* Fail 1/cfs_fail_val times */
  63        if (cfs_fail_loc & CFS_FAIL_RAND) {
  64                if (cfs_fail_val < 2 || cfs_rand() % cfs_fail_val > 0)
  65                        return 0;
  66        }
  67
  68        /* Skip the first cfs_fail_val, then fail */
  69        if (cfs_fail_loc & CFS_FAIL_SKIP) {
  70                if (atomic_inc_return(&cfs_fail_count) <= cfs_fail_val)
  71                        return 0;
  72        }
  73
  74        /* check cfs_fail_val... */
  75        if (set == CFS_FAIL_LOC_VALUE) {
  76                if (cfs_fail_val != -1 && cfs_fail_val != value)
  77                        return 0;
  78        }
  79
  80        /* Fail cfs_fail_val times, overridden by FAIL_ONCE */
  81        if (cfs_fail_loc & CFS_FAIL_SOME &&
  82            (!(cfs_fail_loc & CFS_FAIL_ONCE) || cfs_fail_val <= 1)) {
  83                int count = atomic_inc_return(&cfs_fail_count);
  84
  85                if (count >= cfs_fail_val) {
  86                        set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  87                        atomic_set(&cfs_fail_count, 0);
  88                        /* we are lost race to increase  */
  89                        if (count > cfs_fail_val)
  90                                return 0;
  91                }
  92        }
  93
  94        if ((set == CFS_FAIL_LOC_ORSET || set == CFS_FAIL_LOC_RESET) &&
  95            (value & CFS_FAIL_ONCE))
  96                set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  97        /* Lost race to set CFS_FAILED_BIT. */
  98        if (test_and_set_bit(CFS_FAILED_BIT, &cfs_fail_loc)) {
  99                /* If CFS_FAIL_ONCE is valid, only one process can fail,
 100                 * otherwise multi-process can fail at the same time. */
 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}
 122EXPORT_SYMBOL(__cfs_fail_check_set);
 123
 124int __cfs_fail_timeout_set(__u32 id, __u32 value, int ms, int set)
 125{
 126        int ret = 0;
 127
 128        ret = __cfs_fail_check_set(id, value, set);
 129        if (ret) {
 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}
 138EXPORT_SYMBOL(__cfs_fail_timeout_set);
 139