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  * 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, 2015, 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
  38 unsigned long cfs_fail_loc;
  39 EXPORT_SYMBOL(cfs_fail_loc);
  40
  41 unsigned int cfs_fail_val;
  42 EXPORT_SYMBOL(cfs_fail_val);
  43
  44 int cfs_fail_err;
  45 EXPORT_SYMBOL(cfs_fail_err);
  46
  47 DECLARE_WAIT_QUEUE_HEAD(cfs_race_waitq);
  48 EXPORT_SYMBOL(cfs_race_waitq);
  49
  50 int cfs_race_state;
  51 EXPORT_SYMBOL(cfs_race_state);
  52
  53 int __cfs_fail_check_set(__u32 id, __u32 value, int set)
  54 {
  55         static atomic_t cfs_fail_count = ATOMIC_INIT(0);
  56
  57         LASSERT(!(id & CFS_FAIL_ONCE));
  58
  59         if ((cfs_fail_loc & (CFS_FAILED | CFS_FAIL_ONCE)) ==
  60             (CFS_FAILED | CFS_FAIL_ONCE)) {
  61                 atomic_set(&cfs_fail_count, 0); /* paranoia */
  62                 return 0;
  63         }
  64
  65         /* Fail 1/cfs_fail_val times */
  66         if (cfs_fail_loc & CFS_FAIL_RAND) {
  67                 if (cfs_fail_val < 2 || cfs_rand() % cfs_fail_val > 0)
  68                         return 0;
  69         }
  70
  71         /* Skip the first cfs_fail_val, then fail */
  72         if (cfs_fail_loc & CFS_FAIL_SKIP) {
  73                 if (atomic_inc_return(&cfs_fail_count) <= cfs_fail_val)
  74                         return 0;
  75         }
  76
  77         /* check cfs_fail_val... */
  78         if (set == CFS_FAIL_LOC_VALUE) {
  79                 if (cfs_fail_val != -1 && cfs_fail_val != value)
  80                         return 0;
  81         }
  82
  83         /* Fail cfs_fail_val times, overridden by FAIL_ONCE */
  84         if (cfs_fail_loc & CFS_FAIL_SOME &&
  85             (!(cfs_fail_loc & CFS_FAIL_ONCE) || cfs_fail_val <= 1)) {
  86                 int count = atomic_inc_return(&cfs_fail_count);
  87
  88                 if (count >= cfs_fail_val) {
  89                         set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
  90                         atomic_set(&cfs_fail_count, 0);
  91                         /* we are lost race to increase  */
  92                         if (count > cfs_fail_val)
  93                                 return 0;
  94                 }
  95         }
  96
  97         if ((set == CFS_FAIL_LOC_ORSET || set == CFS_FAIL_LOC_RESET) &&
  98             (value & CFS_FAIL_ONCE))
  99                 set_bit(CFS_FAIL_ONCE_BIT, &cfs_fail_loc);
 100         /* Lost race to set CFS_FAILED_BIT. */
 101         if (test_and_set_bit(CFS_FAILED_BIT, &cfs_fail_loc)) {
 102                 /* If CFS_FAIL_ONCE is valid, only one process can fail,
 103                  * otherwise multi-process can fail at the same time.
 104                  */
 105                 if (cfs_fail_loc & CFS_FAIL_ONCE)
 106                         return 0;
 107         }
 108
 109         switch (set) {
 110         case CFS_FAIL_LOC_NOSET:
 111         case CFS_FAIL_LOC_VALUE:
 112                 break;
 113         case CFS_FAIL_LOC_ORSET:
 114                 cfs_fail_loc |= value & ~(CFS_FAILED | CFS_FAIL_ONCE);
 115                 break;
 116         case CFS_FAIL_LOC_RESET:
 117                 cfs_fail_loc = value;
 118                 break;
 119         default:
 120                 LASSERTF(0, "called with bad set %u\n", set);
 121                 break;
 122         }
 123
 124         return 1;
 125 }
 126 EXPORT_SYMBOL(__cfs_fail_check_set);
 127
 128 int __cfs_fail_timeout_set(__u32 id, __u32 value, int ms, int set)
 129 {
 130         int ret;
 131
 132         ret = __cfs_fail_check_set(id, value, set);
 133         if (ret && likely(ms > 0)) {
 134                 CERROR("cfs_fail_timeout id %x sleeping for %dms\n",
 135                        id, ms);
 136                 set_current_state(TASK_UNINTERRUPTIBLE);
 137                 schedule_timeout(cfs_time_seconds(ms) / 1000);
 138                 CERROR("cfs_fail_timeout id %x awake\n", id);
 139         }
 140         return ret;
 141 }
 142 EXPORT_SYMBOL(__cfs_fail_timeout_set);