lustre/obdclass/lustre_handles.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Copyright (C) 2002 Cluster File Systems, Inc.
   5  *   Author: Phil Schwan <phil@clusterfs.com>
   6  *
   7  *   This file is part of Lustre, http://www.lustre.org/
   8  *
   9  *   Lustre is free software; you can redistribute it and/or
  10  *   modify it under the terms of version 2 of the GNU General Public
  11  *   License as published by the Free Software Foundation.
  12  *
  13  *   Lustre is distributed in the hope that it will be useful,
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *   GNU General Public License for more details.
  17  *
  18  *   You should have received a copy of the GNU General Public License
  19  *   along with Lustre; if not, write to the Free Software
  20  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #define DEBUG_SUBSYSTEM S_CLASS
  24 #ifdef __KERNEL__
  25 # include <linux/types.h>
  26 # include <linux/random.h>
  27 #else
  28 # include <liblustre.h>
  29 #endif
  30
  31 #include <linux/obd_support.h>
  32 #include <linux/lustre_handles.h>
  33
  34 static spinlock_t handle_lock = SPIN_LOCK_UNLOCKED;
  35 static spinlock_t random_lock = SPIN_LOCK_UNLOCKED;
  36 static struct list_head *handle_hash = NULL;
  37 static int handle_count = 0;
  38
  39 #define HANDLE_HASH_SIZE (1 << 14)
  40 #define HANDLE_HASH_MASK (HANDLE_HASH_SIZE - 1)
  41
  42 void class_handle_hash(struct portals_handle *h, portals_handle_addref_cb cb)
  43 {
  44         struct list_head *bucket;
  45         ENTRY;
  46
  47         LASSERT(h != NULL);
  48         LASSERT(list_empty(&h->h_link));
  49
  50         /* My hypothesis is that get_random_bytes, if called from two threads at
  51          * the same time, will return the same bytes. -phil */
  52         spin_lock(&random_lock);
  53         get_random_bytes(&h->h_cookie, sizeof(h->h_cookie));
  54         spin_unlock(&random_lock);
  55
  56         h->h_addref = cb;
  57
  58         bucket = handle_hash + (h->h_cookie & HANDLE_HASH_MASK);
  59
  60         CDEBUG(D_INFO, "adding object %p with handle "LPX64" to hash\n",
  61                h, h->h_cookie);
  62
  63         spin_lock(&handle_lock);
  64         list_add(&h->h_link, bucket);
  65         handle_count++;
  66         spin_unlock(&handle_lock);
  67         EXIT;
  68 }
  69
  70 static void class_handle_unhash_nolock(struct portals_handle *h)
  71 {
  72         LASSERT(!list_empty(&h->h_link));
  73
  74         CDEBUG(D_INFO, "removing object %p with handle "LPX64" from hash\n",
  75                h, h->h_cookie);
  76
  77         handle_count--;
  78         list_del_init(&h->h_link);
  79 }
  80
  81 void class_handle_unhash(struct portals_handle *h)
  82 {
  83         spin_lock(&handle_lock);
  84         class_handle_unhash_nolock(h);
  85         spin_unlock(&handle_lock);
  86 }
  87
  88 void *class_handle2object(__u64 cookie)
  89 {
  90         struct list_head *bucket, *tmp;
  91         void *retval = NULL;
  92         ENTRY;
  93
  94         LASSERT(handle_hash != NULL);
  95
  96         spin_lock(&handle_lock);
  97         bucket = handle_hash + (cookie & HANDLE_HASH_MASK);
  98
  99         list_for_each(tmp, bucket) {
 100                 struct portals_handle *h;
 101                 h = list_entry(tmp, struct portals_handle, h_link);
 102
 103                 if (h->h_cookie == cookie) {
 104                         h->h_addref(h);
 105                         retval = h;
 106                         break;
 107                 }
 108         }
 109         spin_unlock(&handle_lock);
 110
 111         RETURN(retval);
 112 }
 113
 114 int class_handle_init(void)
 115 {
 116         struct list_head *bucket;
 117
 118         LASSERT(handle_hash == NULL);
 119
 120         OBD_VMALLOC(handle_hash, sizeof(*handle_hash) * HANDLE_HASH_SIZE);
 121         if (handle_hash == NULL)
 122                 return -ENOMEM;
 123
 124         for (bucket = handle_hash + HANDLE_HASH_SIZE - 1; bucket >= handle_hash;
 125              bucket--)
 126                 INIT_LIST_HEAD(bucket);
 127
 128         return 0;
 129 }
 130
 131 static void cleanup_all_handles(void)
 132 {
 133         int i;
 134
 135         spin_lock(&handle_lock);
 136         for (i = 0; i < HANDLE_HASH_SIZE; i++) {
 137                 struct list_head *tmp, *pos;
 138                 list_for_each_safe(tmp, pos, &(handle_hash[i])) {
 139                         struct portals_handle *h;
 140                         h = list_entry(tmp, struct portals_handle, h_link);
 141
 142                         CERROR("forcing cleanup for handle "LPX64"\n",
 143                                h->h_cookie);
 144
 145                         class_handle_unhash_nolock(h);
 146                 }
 147         }
 148         spin_unlock(&handle_lock);
 149 }
 150
 151 void class_handle_cleanup(void)
 152 {
 153         LASSERT(handle_hash != NULL);
 154
 155         if (handle_count != 0) {
 156                 CERROR("handle_count at cleanup: %d\n", handle_count);
 157                 cleanup_all_handles();
 158         }
 159
 160         OBD_VFREE(handle_hash, sizeof(*handle_hash) * HANDLE_HASH_SIZE);
 161         handle_hash = NULL;
 162
 163         if (handle_count)
 164                 CERROR("leaked %d handles\n", handle_count);
 165 }