mirror of https://gitee.com/openkylin/linux.git
135 lines
3.1 KiB
C
135 lines
3.1 KiB
C
/*
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* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <xfs.h>
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static DEFINE_MUTEX(uuid_monitor);
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static int uuid_table_size;
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static uuid_t *uuid_table;
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/* IRIX interpretation of an uuid_t */
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typedef struct {
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__be32 uu_timelow;
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__be16 uu_timemid;
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__be16 uu_timehi;
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__be16 uu_clockseq;
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__be16 uu_node[3];
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} xfs_uu_t;
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/*
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* uuid_getnodeuniq - obtain the node unique fields of a UUID.
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*
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* This is not in any way a standard or condoned UUID function;
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* it just something that's needed for user-level file handles.
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*/
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void
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uuid_getnodeuniq(uuid_t *uuid, int fsid [2])
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{
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xfs_uu_t *uup = (xfs_uu_t *)uuid;
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fsid[0] = (be16_to_cpu(uup->uu_clockseq) << 16) |
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be16_to_cpu(uup->uu_timemid);
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fsid[1] = be32_to_cpu(uup->uu_timelow);
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}
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void
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uuid_create_nil(uuid_t *uuid)
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{
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memset(uuid, 0, sizeof(*uuid));
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}
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int
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uuid_is_nil(uuid_t *uuid)
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{
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int i;
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char *cp = (char *)uuid;
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if (uuid == NULL)
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return 0;
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/* implied check of version number here... */
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for (i = 0; i < sizeof *uuid; i++)
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if (*cp++) return 0; /* not nil */
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return 1; /* is nil */
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}
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int
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uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
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{
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return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
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}
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/*
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* Given a 128-bit uuid, return a 64-bit value by adding the top and bottom
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* 64-bit words. NOTE: This function can not be changed EVER. Although
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* brain-dead, some applications depend on this 64-bit value remaining
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* persistent. Specifically, DMI vendors store the value as a persistent
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* filehandle.
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*/
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__uint64_t
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uuid_hash64(uuid_t *uuid)
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{
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__uint64_t *sp = (__uint64_t *)uuid;
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return sp[0] + sp[1];
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}
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int
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uuid_table_insert(uuid_t *uuid)
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{
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int i, hole;
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mutex_lock(&uuid_monitor);
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for (i = 0, hole = -1; i < uuid_table_size; i++) {
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if (uuid_is_nil(&uuid_table[i])) {
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hole = i;
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continue;
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}
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if (uuid_equal(uuid, &uuid_table[i])) {
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mutex_unlock(&uuid_monitor);
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return 0;
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}
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}
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if (hole < 0) {
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uuid_table = kmem_realloc(uuid_table,
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(uuid_table_size + 1) * sizeof(*uuid_table),
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uuid_table_size * sizeof(*uuid_table),
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KM_SLEEP);
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hole = uuid_table_size++;
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}
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uuid_table[hole] = *uuid;
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mutex_unlock(&uuid_monitor);
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return 1;
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}
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void
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uuid_table_remove(uuid_t *uuid)
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{
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int i;
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mutex_lock(&uuid_monitor);
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for (i = 0; i < uuid_table_size; i++) {
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if (uuid_is_nil(&uuid_table[i]))
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continue;
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if (!uuid_equal(uuid, &uuid_table[i]))
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continue;
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uuid_create_nil(&uuid_table[i]);
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break;
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}
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ASSERT(i < uuid_table_size);
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mutex_unlock(&uuid_monitor);
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}
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