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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2012, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/ptlrpc/sec_gc.c
  33  *
  34  * Author: Eric Mei <ericm@clusterfs.com>
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_SEC
  38
  39 #include "../../include/linux/libcfs/libcfs.h"
  40
  41 #include "../include/obd_support.h"
  42 #include "../include/obd_class.h"
  43 #include "../include/lustre_net.h"
  44 #include "../include/lustre_sec.h"
  45
  46 #include "ptlrpc_internal.h"
  47
  48 #define SEC_GC_INTERVAL (30 * 60)
  49
  50 static struct mutex sec_gc_mutex;
  51 static LIST_HEAD(sec_gc_list);
  52 static spinlock_t sec_gc_list_lock;
  53
  54 static LIST_HEAD(sec_gc_ctx_list);
  55 static spinlock_t sec_gc_ctx_list_lock;
  56
  57 static struct ptlrpc_thread sec_gc_thread;
  58 static atomic_t sec_gc_wait_del = ATOMIC_INIT(0);
  59
  60 void sptlrpc_gc_add_sec(struct ptlrpc_sec *sec)
  61 {
  62         LASSERT(sec->ps_policy->sp_cops->gc_ctx);
  63         LASSERT(sec->ps_gc_interval > 0);
  64         LASSERT(list_empty(&sec->ps_gc_list));
  65
  66         sec->ps_gc_next = ktime_get_real_seconds() + sec->ps_gc_interval;
  67
  68         spin_lock(&sec_gc_list_lock);
  69         list_add_tail(&sec_gc_list, &sec->ps_gc_list);
  70         spin_unlock(&sec_gc_list_lock);
  71
  72         CDEBUG(D_SEC, "added sec %p(%s)\n", sec, sec->ps_policy->sp_name);
  73 }
  74
  75 void sptlrpc_gc_del_sec(struct ptlrpc_sec *sec)
  76 {
  77         if (list_empty(&sec->ps_gc_list))
  78                 return;
  79
  80         might_sleep();
  81
  82         /* signal before list_del to make iteration in gc thread safe */
  83         atomic_inc(&sec_gc_wait_del);
  84
  85         spin_lock(&sec_gc_list_lock);
  86         list_del_init(&sec->ps_gc_list);
  87         spin_unlock(&sec_gc_list_lock);
  88
  89         /* barrier */
  90         mutex_lock(&sec_gc_mutex);
  91         mutex_unlock(&sec_gc_mutex);
  92
  93         atomic_dec(&sec_gc_wait_del);
  94
  95         CDEBUG(D_SEC, "del sec %p(%s)\n", sec, sec->ps_policy->sp_name);
  96 }
  97
  98 static void sec_process_ctx_list(void)
  99 {
 100         struct ptlrpc_cli_ctx *ctx;
 101
 102         spin_lock(&sec_gc_ctx_list_lock);
 103
 104         while (!list_empty(&sec_gc_ctx_list)) {
 105                 ctx = list_entry(sec_gc_ctx_list.next,
 106                                  struct ptlrpc_cli_ctx, cc_gc_chain);
 107                 list_del_init(&ctx->cc_gc_chain);
 108                 spin_unlock(&sec_gc_ctx_list_lock);
 109
 110                 LASSERT(ctx->cc_sec);
 111                 LASSERT(atomic_read(&ctx->cc_refcount) == 1);
 112                 CDEBUG(D_SEC, "gc pick up ctx %p(%u->%s)\n",
 113                        ctx, ctx->cc_vcred.vc_uid, sec2target_str(ctx->cc_sec));
 114                 sptlrpc_cli_ctx_put(ctx, 1);
 115
 116                 spin_lock(&sec_gc_ctx_list_lock);
 117         }
 118
 119         spin_unlock(&sec_gc_ctx_list_lock);
 120 }
 121
 122 static void sec_do_gc(struct ptlrpc_sec *sec)
 123 {
 124         LASSERT(sec->ps_policy->sp_cops->gc_ctx);
 125
 126         if (unlikely(sec->ps_gc_next == 0)) {
 127                 CDEBUG(D_SEC, "sec %p(%s) has 0 gc time\n",
 128                        sec, sec->ps_policy->sp_name);
 129                 return;
 130         }
 131
 132         CDEBUG(D_SEC, "check on sec %p(%s)\n", sec, sec->ps_policy->sp_name);
 133
 134         if (sec->ps_gc_next > ktime_get_real_seconds())
 135                 return;
 136
 137         sec->ps_policy->sp_cops->gc_ctx(sec);
 138         sec->ps_gc_next = ktime_get_real_seconds() + sec->ps_gc_interval;
 139 }
 140
 141 static int sec_gc_main(void *arg)
 142 {
 143         struct ptlrpc_thread *thread = arg;
 144         struct l_wait_info lwi;
 145
 146         unshare_fs_struct();
 147
 148         /* Record that the thread is running */
 149         thread_set_flags(thread, SVC_RUNNING);
 150         wake_up(&thread->t_ctl_waitq);
 151
 152         while (1) {
 153                 struct ptlrpc_sec *sec;
 154
 155                 thread_clear_flags(thread, SVC_SIGNAL);
 156                 sec_process_ctx_list();
 157 again:
 158                 /* go through sec list do gc.
 159                  * FIXME here we iterate through the whole list each time which
 160                  * is not optimal. we perhaps want to use balanced binary tree
 161                  * to trace each sec as order of expiry time.
 162                  * another issue here is we wakeup as fixed interval instead of
 163                  * according to each sec's expiry time
 164                  */
 165                 mutex_lock(&sec_gc_mutex);
 166                 list_for_each_entry(sec, &sec_gc_list, ps_gc_list) {
 167                         /* if someone is waiting to be deleted, let it
 168                          * proceed as soon as possible.
 169                          */
 170                         if (atomic_read(&sec_gc_wait_del)) {
 171                                 CDEBUG(D_SEC, "deletion pending, start over\n");
 172                                 mutex_unlock(&sec_gc_mutex);
 173                                 goto again;
 174                         }
 175
 176                         sec_do_gc(sec);
 177                 }
 178                 mutex_unlock(&sec_gc_mutex);
 179
 180                 /* check ctx list again before sleep */
 181                 sec_process_ctx_list();
 182
 183                 lwi = LWI_TIMEOUT(msecs_to_jiffies(SEC_GC_INTERVAL * MSEC_PER_SEC),
 184                                   NULL, NULL);
 185                 l_wait_event(thread->t_ctl_waitq,
 186                              thread_is_stopping(thread) ||
 187                              thread_is_signal(thread),
 188                              &lwi);
 189
 190                 if (thread_test_and_clear_flags(thread, SVC_STOPPING))
 191                         break;
 192         }
 193
 194         thread_set_flags(thread, SVC_STOPPED);
 195         wake_up(&thread->t_ctl_waitq);
 196         return 0;
 197 }
 198
 199 int sptlrpc_gc_init(void)
 200 {
 201         struct l_wait_info lwi = { 0 };
 202         struct task_struct *task;
 203
 204         mutex_init(&sec_gc_mutex);
 205         spin_lock_init(&sec_gc_list_lock);
 206         spin_lock_init(&sec_gc_ctx_list_lock);
 207
 208         /* initialize thread control */
 209         memset(&sec_gc_thread, 0, sizeof(sec_gc_thread));
 210         init_waitqueue_head(&sec_gc_thread.t_ctl_waitq);
 211
 212         task = kthread_run(sec_gc_main, &sec_gc_thread, "sptlrpc_gc");
 213         if (IS_ERR(task)) {
 214                 CERROR("can't start gc thread: %ld\n", PTR_ERR(task));
 215                 return PTR_ERR(task);
 216         }
 217
 218         l_wait_event(sec_gc_thread.t_ctl_waitq,
 219                      thread_is_running(&sec_gc_thread), &lwi);
 220         return 0;
 221 }
 222
 223 void sptlrpc_gc_fini(void)
 224 {
 225         struct l_wait_info lwi = { 0 };
 226
 227         thread_set_flags(&sec_gc_thread, SVC_STOPPING);
 228         wake_up(&sec_gc_thread.t_ctl_waitq);
 229
 230         l_wait_event(sec_gc_thread.t_ctl_waitq,
 231                      thread_is_stopped(&sec_gc_thread), &lwi);
 232 }