kernel/drivers/staging/lustre/lustre/ptlrpc/sec_gc.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
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2012, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/ptlrpc/sec_gc.c
  37  *
  38  * Author: Eric Mei <ericm@clusterfs.com>
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_SEC
  42
  43 #include "../../include/linux/libcfs/libcfs.h"
  44
  45 #include "../include/obd_support.h"
  46 #include "../include/obd_class.h"
  47 #include "../include/lustre_net.h"
  48 #include "../include/lustre_sec.h"
  49
  50 #include "ptlrpc_internal.h"
  51
  52 #define SEC_GC_INTERVAL (30 * 60)
  53
  54 static struct mutex sec_gc_mutex;
  55 static LIST_HEAD(sec_gc_list);
  56 static spinlock_t sec_gc_list_lock;
  57
  58 static LIST_HEAD(sec_gc_ctx_list);
  59 static spinlock_t sec_gc_ctx_list_lock;
  60
  61 static struct ptlrpc_thread sec_gc_thread;
  62 static atomic_t sec_gc_wait_del = ATOMIC_INIT(0);
  63
  64 void sptlrpc_gc_add_sec(struct ptlrpc_sec *sec)
  65 {
  66         LASSERT(sec->ps_policy->sp_cops->gc_ctx);
  67         LASSERT(sec->ps_gc_interval > 0);
  68         LASSERT(list_empty(&sec->ps_gc_list));
  69
  70         sec->ps_gc_next = ktime_get_real_seconds() + sec->ps_gc_interval;
  71
  72         spin_lock(&sec_gc_list_lock);
  73         list_add_tail(&sec_gc_list, &sec->ps_gc_list);
  74         spin_unlock(&sec_gc_list_lock);
  75
  76         CDEBUG(D_SEC, "added sec %p(%s)\n", sec, sec->ps_policy->sp_name);
  77 }
  78 EXPORT_SYMBOL(sptlrpc_gc_add_sec);
  79
  80 void sptlrpc_gc_del_sec(struct ptlrpc_sec *sec)
  81 {
  82         if (list_empty(&sec->ps_gc_list))
  83                 return;
  84
  85         might_sleep();
  86
  87         /* signal before list_del to make iteration in gc thread safe */
  88         atomic_inc(&sec_gc_wait_del);
  89
  90         spin_lock(&sec_gc_list_lock);
  91         list_del_init(&sec->ps_gc_list);
  92         spin_unlock(&sec_gc_list_lock);
  93
  94         /* barrier */
  95         mutex_lock(&sec_gc_mutex);
  96         mutex_unlock(&sec_gc_mutex);
  97
  98         atomic_dec(&sec_gc_wait_del);
  99
 100         CDEBUG(D_SEC, "del sec %p(%s)\n", sec, sec->ps_policy->sp_name);
 101 }
 102 EXPORT_SYMBOL(sptlrpc_gc_del_sec);
 103
 104 static void sec_process_ctx_list(void)
 105 {
 106         struct ptlrpc_cli_ctx *ctx;
 107
 108         spin_lock(&sec_gc_ctx_list_lock);
 109
 110         while (!list_empty(&sec_gc_ctx_list)) {
 111                 ctx = list_entry(sec_gc_ctx_list.next,
 112                                      struct ptlrpc_cli_ctx, cc_gc_chain);
 113                 list_del_init(&ctx->cc_gc_chain);
 114                 spin_unlock(&sec_gc_ctx_list_lock);
 115
 116                 LASSERT(ctx->cc_sec);
 117                 LASSERT(atomic_read(&ctx->cc_refcount) == 1);
 118                 CDEBUG(D_SEC, "gc pick up ctx %p(%u->%s)\n",
 119                        ctx, ctx->cc_vcred.vc_uid, sec2target_str(ctx->cc_sec));
 120                 sptlrpc_cli_ctx_put(ctx, 1);
 121
 122                 spin_lock(&sec_gc_ctx_list_lock);
 123         }
 124
 125         spin_unlock(&sec_gc_ctx_list_lock);
 126 }
 127
 128 static void sec_do_gc(struct ptlrpc_sec *sec)
 129 {
 130         LASSERT(sec->ps_policy->sp_cops->gc_ctx);
 131
 132         if (unlikely(sec->ps_gc_next == 0)) {
 133                 CDEBUG(D_SEC, "sec %p(%s) has 0 gc time\n",
 134                       sec, sec->ps_policy->sp_name);
 135                 return;
 136         }
 137
 138         CDEBUG(D_SEC, "check on sec %p(%s)\n", sec, sec->ps_policy->sp_name);
 139
 140         if (sec->ps_gc_next > ktime_get_real_seconds())
 141                 return;
 142
 143         sec->ps_policy->sp_cops->gc_ctx(sec);
 144         sec->ps_gc_next = ktime_get_real_seconds() + sec->ps_gc_interval;
 145 }
 146
 147 static int sec_gc_main(void *arg)
 148 {
 149         struct ptlrpc_thread *thread = arg;
 150         struct l_wait_info lwi;
 151
 152         unshare_fs_struct();
 153
 154         /* Record that the thread is running */
 155         thread_set_flags(thread, SVC_RUNNING);
 156         wake_up(&thread->t_ctl_waitq);
 157
 158         while (1) {
 159                 struct ptlrpc_sec *sec;
 160
 161                 thread_clear_flags(thread, SVC_SIGNAL);
 162                 sec_process_ctx_list();
 163 again:
 164                 /* go through sec list do gc.
 165                  * FIXME here we iterate through the whole list each time which
 166                  * is not optimal. we perhaps want to use balanced binary tree
 167                  * to trace each sec as order of expiry time.
 168                  * another issue here is we wakeup as fixed interval instead of
 169                  * according to each sec's expiry time */
 170                 mutex_lock(&sec_gc_mutex);
 171                 list_for_each_entry(sec, &sec_gc_list, ps_gc_list) {
 172                         /* if someone is waiting to be deleted, let it
 173                          * proceed as soon as possible. */
 174                         if (atomic_read(&sec_gc_wait_del)) {
 175                                 CDEBUG(D_SEC, "deletion pending, start over\n");
 176                                 mutex_unlock(&sec_gc_mutex);
 177                                 goto again;
 178                         }
 179
 180                         sec_do_gc(sec);
 181                 }
 182                 mutex_unlock(&sec_gc_mutex);
 183
 184                 /* check ctx list again before sleep */
 185                 sec_process_ctx_list();
 186
 187                 lwi = LWI_TIMEOUT(SEC_GC_INTERVAL * HZ, NULL, NULL);
 188                 l_wait_event(thread->t_ctl_waitq,
 189                              thread_is_stopping(thread) ||
 190                              thread_is_signal(thread),
 191                              &lwi);
 192
 193                 if (thread_test_and_clear_flags(thread, SVC_STOPPING))
 194                         break;
 195         }
 196
 197         thread_set_flags(thread, SVC_STOPPED);
 198         wake_up(&thread->t_ctl_waitq);
 199         return 0;
 200 }
 201
 202 int sptlrpc_gc_init(void)
 203 {
 204         struct l_wait_info lwi = { 0 };
 205         struct task_struct *task;
 206
 207         mutex_init(&sec_gc_mutex);
 208         spin_lock_init(&sec_gc_list_lock);
 209         spin_lock_init(&sec_gc_ctx_list_lock);
 210
 211         /* initialize thread control */
 212         memset(&sec_gc_thread, 0, sizeof(sec_gc_thread));
 213         init_waitqueue_head(&sec_gc_thread.t_ctl_waitq);
 214
 215         task = kthread_run(sec_gc_main, &sec_gc_thread, "sptlrpc_gc");
 216         if (IS_ERR(task)) {
 217                 CERROR("can't start gc thread: %ld\n", PTR_ERR(task));
 218                 return PTR_ERR(task);
 219         }
 220
 221         l_wait_event(sec_gc_thread.t_ctl_waitq,
 222                      thread_is_running(&sec_gc_thread), &lwi);
 223         return 0;
 224 }
 225
 226 void sptlrpc_gc_fini(void)
 227 {
 228         struct l_wait_info lwi = { 0 };
 229
 230         thread_set_flags(&sec_gc_thread, SVC_STOPPING);
 231         wake_up(&sec_gc_thread.t_ctl_waitq);
 232
 233         l_wait_event(sec_gc_thread.t_ctl_waitq,
 234                      thread_is_stopped(&sec_gc_thread), &lwi);
 235 }