fs/xfs/support/uuid.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include <xfs.h>
  19
  20 static mutex_t  uuid_monitor;
  21 static int      uuid_table_size;
  22 static uuid_t   *uuid_table;
  23
  24 void
  25 uuid_init(void)
  26 {
  27         mutex_init(&uuid_monitor, MUTEX_DEFAULT, "uuid_monitor");
  28 }
  29
  30 /*
  31  * uuid_getnodeuniq - obtain the node unique fields of a UUID.
  32  *
  33  * This is not in any way a standard or condoned UUID function;
  34  * it just something that's needed for user-level file handles.
  35  */
  36 void
  37 uuid_getnodeuniq(uuid_t *uuid, int fsid [2])
  38 {
  39         char    *uu = (char *)uuid;
  40
  41         /* on IRIX, this function assumes big-endian fields within
  42          * the uuid, so we use INT_GET to get the same result on
  43          * little-endian systems
  44          */
  45
  46         fsid[0] = (INT_GET(*(u_int16_t*)(uu+8), ARCH_CONVERT) << 16) +
  47                    INT_GET(*(u_int16_t*)(uu+4), ARCH_CONVERT);
  48         fsid[1] =  INT_GET(*(u_int32_t*)(uu  ), ARCH_CONVERT);
  49 }
  50
  51 void
  52 uuid_create_nil(uuid_t *uuid)
  53 {
  54         memset(uuid, 0, sizeof(*uuid));
  55 }
  56
  57 int
  58 uuid_is_nil(uuid_t *uuid)
  59 {
  60         int     i;
  61         char    *cp = (char *)uuid;
  62
  63         if (uuid == NULL)
  64                 return 0;
  65         /* implied check of version number here... */
  66         for (i = 0; i < sizeof *uuid; i++)
  67                 if (*cp++) return 0;    /* not nil */
  68         return 1;       /* is nil */
  69 }
  70
  71 int
  72 uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
  73 {
  74         return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
  75 }
  76
  77 /*
  78  * Given a 128-bit uuid, return a 64-bit value by adding the top and bottom
  79  * 64-bit words.  NOTE: This function can not be changed EVER.  Although
  80  * brain-dead, some applications depend on this 64-bit value remaining
  81  * persistent.  Specifically, DMI vendors store the value as a persistent
  82  * filehandle.
  83  */
  84 __uint64_t
  85 uuid_hash64(uuid_t *uuid)
  86 {
  87         __uint64_t      *sp = (__uint64_t *)uuid;
  88
  89         return sp[0] + sp[1];
  90 }
  91
  92 int
  93 uuid_table_insert(uuid_t *uuid)
  94 {
  95         int     i, hole;
  96
  97         mutex_lock(&uuid_monitor, PVFS);
  98         for (i = 0, hole = -1; i < uuid_table_size; i++) {
  99                 if (uuid_is_nil(&uuid_table[i])) {
 100                         hole = i;
 101                         continue;
 102                 }
 103                 if (uuid_equal(uuid, &uuid_table[i])) {
 104                         mutex_unlock(&uuid_monitor);
 105                         return 0;
 106                 }
 107         }
 108         if (hole < 0) {
 109                 uuid_table = kmem_realloc(uuid_table,
 110                         (uuid_table_size + 1) * sizeof(*uuid_table),
 111                         uuid_table_size  * sizeof(*uuid_table),
 112                         KM_SLEEP);
 113                 hole = uuid_table_size++;
 114         }
 115         uuid_table[hole] = *uuid;
 116         mutex_unlock(&uuid_monitor);
 117         return 1;
 118 }
 119
 120 void
 121 uuid_table_remove(uuid_t *uuid)
 122 {
 123         int     i;
 124
 125         mutex_lock(&uuid_monitor, PVFS);
 126         for (i = 0; i < uuid_table_size; i++) {
 127                 if (uuid_is_nil(&uuid_table[i]))
 128                         continue;
 129                 if (!uuid_equal(uuid, &uuid_table[i]))
 130                         continue;
 131                 uuid_create_nil(&uuid_table[i]);
 132                 break;
 133         }
 134         ASSERT(i < uuid_table_size);
 135         mutex_unlock(&uuid_monitor);
 136 }