/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  lustre/lvfs/lvfs_lib.c
 *  Lustre filesystem abstraction routines
 *
 *  Copyright (C) 2007 Cluster File Systems, Inc.
 *   Author: Andreas Dilger <adilger@clusterfs.com>
 *
 *   This file is part of Lustre, http://www.lustre.org.
 *
 *   Lustre is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Lustre is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Lustre; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#ifdef __KERNEL__
#include <linux/module.h>
#include <linux/random.h>
#else
#include <liblustre.h>
#endif
#include <lustre_lib.h>

unsigned int obd_fail_val = 0;
unsigned long obd_fail_loc = 0;
unsigned int obd_alloc_fail_rate = 0;

int obd_alloc_fail(const void *ptr, const char *name, const char *type,
                   size_t size, const char *file, int line)
{
        if (ptr == NULL ||
            (ll_rand() & OBD_ALLOC_FAIL_MASK) < obd_alloc_fail_rate) {
                CERROR("%s%salloc of %s ("LPU64" bytes) failed at %s:%d\n",
                       ptr ? "force " :"", type, name, (__u64)size, file,
                       line);
                CERROR(LPU64" total bytes and "LPU64" total pages "
                       "("LPU64" bytes) allocated by Lustre, "
                       "%d total bytes by LNET\n",
                       obd_memory_sum(),
                       obd_pages_sum() << CFS_PAGE_SHIFT,
                       obd_pages_sum(),
                       atomic_read(&libcfs_kmemory));                
                return 1;
        }
        return 0;
}
EXPORT_SYMBOL(obd_alloc_fail);

int __obd_fail_check_set(__u32 id, __u32 value, int set)
{
        static atomic_t obd_fail_count = ATOMIC_INIT(0);

        LASSERT(!(id & OBD_FAIL_ONCE));

        if ((obd_fail_loc & (OBD_FAILED | OBD_FAIL_ONCE)) ==
            (OBD_FAILED | OBD_FAIL_ONCE)) {
                atomic_set(&obd_fail_count, 0); /* paranoia */
                return 0;
        }

        /* Fail 1/obd_fail_val times */
        if (obd_fail_loc & OBD_FAIL_RAND) {
                if (obd_fail_val < 2 || ll_rand() % obd_fail_val > 0)
                        return 0;
        }

        /* Skip the first obd_fail_val, then fail */
        if (obd_fail_loc & OBD_FAIL_SKIP) {
                if (atomic_inc_return(&obd_fail_count) <= obd_fail_val)
                        return 0;
        }

        /* Fail obd_fail_val times, overridden by FAIL_ONCE */
        if (obd_fail_loc & OBD_FAIL_SOME &&
            (!(obd_fail_loc & OBD_FAIL_ONCE) || obd_fail_val <= 1)) { 
                int count = atomic_inc_return(&obd_fail_count);

                if (count >= obd_fail_val) {
                        set_bit(OBD_FAIL_ONCE_BIT, &obd_fail_loc);
                        atomic_set(&obd_fail_count, 0);
                        /* we are lost race to increase obd_fail_count */
                        if (count > obd_fail_val)
                                return 0;
                }
        }

        if ((set == OBD_FAIL_LOC_ORSET || set == OBD_FAIL_LOC_RESET) &&
            (value & OBD_FAIL_ONCE))
                set_bit(OBD_FAIL_ONCE_BIT, &obd_fail_loc);

        /* Lost race to set OBD_FAILED_BIT. */
        if (test_and_set_bit(OBD_FAILED_BIT, &obd_fail_loc)) {
                /* If OBD_FAIL_ONCE is valid, only one process can fail,
                 * otherwise multi-process can fail at the same time. */
                if (obd_fail_loc & OBD_FAIL_ONCE)
                        return 0;
        }

        switch (set) {
                case OBD_FAIL_LOC_NOSET:
                        break;
                case OBD_FAIL_LOC_ORSET:
                        obd_fail_loc |= value & ~(OBD_FAILED | OBD_FAIL_ONCE);
                        break;
                case OBD_FAIL_LOC_RESET:
                        obd_fail_loc = value;
                        break;
                default:
                        LASSERTF(0, "called with bad set %u\n", set);
                        break;
        }

        return 1;
}
EXPORT_SYMBOL(__obd_fail_check_set);

EXPORT_SYMBOL(obd_fail_loc);
EXPORT_SYMBOL(obd_alloc_fail_rate);
EXPORT_SYMBOL(obd_fail_val);