fs/xfs/support/uuid.c

   1 /*
   2  * Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32
  33 #include <xfs.h>
  34
  35 static mutex_t  uuid_monitor;
  36 static int      uuid_table_size;
  37 static uuid_t   *uuid_table;
  38
  39 void
  40 uuid_init(void)
  41 {
  42         mutex_init(&uuid_monitor, MUTEX_DEFAULT, "uuid_monitor");
  43 }
  44
  45 /*
  46  * uuid_getnodeuniq - obtain the node unique fields of a UUID.
  47  *
  48  * This is not in any way a standard or condoned UUID function;
  49  * it just something that's needed for user-level file handles.
  50  */
  51 void
  52 uuid_getnodeuniq(uuid_t *uuid, int fsid [2])
  53 {
  54         char    *uu = (char *)uuid;
  55
  56         /* on IRIX, this function assumes big-endian fields within
  57          * the uuid, so we use INT_GET to get the same result on
  58          * little-endian systems
  59          */
  60
  61         fsid[0] = (INT_GET(*(u_int16_t*)(uu+8), ARCH_CONVERT) << 16) +
  62                    INT_GET(*(u_int16_t*)(uu+4), ARCH_CONVERT);
  63         fsid[1] =  INT_GET(*(u_int32_t*)(uu  ), ARCH_CONVERT);
  64 }
  65
  66 void
  67 uuid_create_nil(uuid_t *uuid)
  68 {
  69         memset(uuid, 0, sizeof(*uuid));
  70 }
  71
  72 int
  73 uuid_is_nil(uuid_t *uuid)
  74 {
  75         int     i;
  76         char    *cp = (char *)uuid;
  77
  78         if (uuid == NULL)
  79                 return 0;
  80         /* implied check of version number here... */
  81         for (i = 0; i < sizeof *uuid; i++)
  82                 if (*cp++) return 0;    /* not nil */
  83         return 1;       /* is nil */
  84 }
  85
  86 int
  87 uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
  88 {
  89         return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
  90 }
  91
  92 /*
  93  * Given a 128-bit uuid, return a 64-bit value by adding the top and bottom
  94  * 64-bit words.  NOTE: This function can not be changed EVER.  Although
  95  * brain-dead, some applications depend on this 64-bit value remaining
  96  * persistent.  Specifically, DMI vendors store the value as a persistent
  97  * filehandle.
  98  */
  99 __uint64_t
 100 uuid_hash64(uuid_t *uuid)
 101 {
 102         __uint64_t      *sp = (__uint64_t *)uuid;
 103
 104         return sp[0] + sp[1];
 105 }
 106
 107 int
 108 uuid_table_insert(uuid_t *uuid)
 109 {
 110         int     i, hole;
 111
 112         mutex_lock(&uuid_monitor, PVFS);
 113         for (i = 0, hole = -1; i < uuid_table_size; i++) {
 114                 if (uuid_is_nil(&uuid_table[i])) {
 115                         hole = i;
 116                         continue;
 117                 }
 118                 if (uuid_equal(uuid, &uuid_table[i])) {
 119                         mutex_unlock(&uuid_monitor);
 120                         return 0;
 121                 }
 122         }
 123         if (hole < 0) {
 124                 uuid_table = kmem_realloc(uuid_table,
 125                         (uuid_table_size + 1) * sizeof(*uuid_table),
 126                         uuid_table_size  * sizeof(*uuid_table),
 127                         KM_SLEEP);
 128                 hole = uuid_table_size++;
 129         }
 130         uuid_table[hole] = *uuid;
 131         mutex_unlock(&uuid_monitor);
 132         return 1;
 133 }
 134
 135 void
 136 uuid_table_remove(uuid_t *uuid)
 137 {
 138         int     i;
 139
 140         mutex_lock(&uuid_monitor, PVFS);
 141         for (i = 0; i < uuid_table_size; i++) {
 142                 if (uuid_is_nil(&uuid_table[i]))
 143                         continue;
 144                 if (!uuid_equal(uuid, &uuid_table[i]))
 145                         continue;
 146                 uuid_create_nil(&uuid_table[i]);
 147                 break;
 148         }
 149         ASSERT(i < uuid_table_size);
 150         mutex_unlock(&uuid_monitor);
 151 }