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/*
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/*
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 * Copyright (c) 2008 Jakub Jermar
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 * Copyright (c) 2008 Jakub Jermar
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 * All rights reserved.
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 * All rights reserved.
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 *
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * are met:
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 *
8
 *
9
 * - Redistributions of source code must retain the above copyright
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *   derived from this software without specific prior written permission.
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 *
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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 */
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/** @addtogroup fs
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/** @addtogroup fs
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 * @{
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 * @{
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 */
31
 */
32
 
32
 
33
/**
33
/**
34
 * @file    vfs_node.c
34
 * @file    vfs_node.c
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 * @brief   Various operations on VFS nodes have their home in this file.
35
 * @brief   Various operations on VFS nodes have their home in this file.
36
 */
36
 */
37
 
37
 
38
#include "vfs.h"
38
#include "vfs.h"
39
#include <stdlib.h>
39
#include <stdlib.h>
40
#include <string.h>
40
#include <string.h>
41
#include <atomic.h>
41
#include <atomic.h>
42
#include <futex.h>
42
#include <futex.h>
43
#include <rwlock.h>
43
#include <rwlock.h>
44
#include <libadt/hash_table.h>
44
#include <libadt/hash_table.h>
45
#include <assert.h>
45
#include <assert.h>
46
#include <async.h>
46
#include <async.h>
47
#include <errno.h>
47
#include <errno.h>
48
 
48
 
49
/** Futex protecting the VFS node hash table. */
49
/** Futex protecting the VFS node hash table. */
50
atomic_t nodes_futex = FUTEX_INITIALIZER;
50
atomic_t nodes_futex = FUTEX_INITIALIZER;
51
 
51
 
52
#define NODES_BUCKETS_LOG   8
52
#define NODES_BUCKETS_LOG   8
53
#define NODES_BUCKETS       (1 << NODES_BUCKETS_LOG)
53
#define NODES_BUCKETS       (1 << NODES_BUCKETS_LOG)
54
 
54
 
55
/** VFS node hash table containing all active, in-memory VFS nodes. */
55
/** VFS node hash table containing all active, in-memory VFS nodes. */
56
hash_table_t nodes;
56
hash_table_t nodes;
57
 
57
 
58
#define KEY_FS_HANDLE   0
58
#define KEY_FS_HANDLE   0
59
#define KEY_DEV_HANDLE  1
59
#define KEY_DEV_HANDLE  1
60
#define KEY_INDEX   2
60
#define KEY_INDEX   2
61
 
61
 
62
static hash_index_t nodes_hash(unsigned long []);
62
static hash_index_t nodes_hash(unsigned long []);
63
static int nodes_compare(unsigned long [], hash_count_t, link_t *);
63
static int nodes_compare(unsigned long [], hash_count_t, link_t *);
64
static void nodes_remove_callback(link_t *);
64
static void nodes_remove_callback(link_t *);
65
 
65
 
66
/** VFS node hash table operations. */
66
/** VFS node hash table operations. */
67
hash_table_operations_t nodes_ops = {
67
hash_table_operations_t nodes_ops = {
68
    .hash = nodes_hash,
68
    .hash = nodes_hash,
69
    .compare = nodes_compare,
69
    .compare = nodes_compare,
70
    .remove_callback = nodes_remove_callback
70
    .remove_callback = nodes_remove_callback
71
};
71
};
72
 
72
 
73
/** Initialize the VFS node hash table.
73
/** Initialize the VFS node hash table.
74
 *
74
 *
75
 * @return      Return true on success, false on failure.
75
 * @return      Return true on success, false on failure.
76
 */
76
 */
77
bool vfs_nodes_init(void)
77
bool vfs_nodes_init(void)
78
{
78
{
79
    return hash_table_create(&nodes, NODES_BUCKETS, 3, &nodes_ops);
79
    return hash_table_create(&nodes, NODES_BUCKETS, 3, &nodes_ops);
80
}
80
}
81
 
81
 
82
static inline void _vfs_node_addref(vfs_node_t *node)
82
static inline void _vfs_node_addref(vfs_node_t *node)
83
{
83
{
84
    node->refcnt++;
84
    node->refcnt++;
85
}
85
}
86
 
86
 
87
/** Increment reference count of a VFS node.
87
/** Increment reference count of a VFS node.
88
 *
88
 *
89
 * @param node      VFS node that will have its refcnt incremented.
89
 * @param node      VFS node that will have its refcnt incremented.
90
 */
90
 */
91
void vfs_node_addref(vfs_node_t *node)
91
void vfs_node_addref(vfs_node_t *node)
92
{
92
{
93
    futex_down(&nodes_futex);
93
    futex_down(&nodes_futex);
94
    _vfs_node_addref(node);
94
    _vfs_node_addref(node);
95
    futex_up(&nodes_futex);
95
    futex_up(&nodes_futex);
96
}
96
}
97
 
97
 
98
/** Decrement reference count of a VFS node.
98
/** Decrement reference count of a VFS node.
99
 *
99
 *
100
 * This function handles the case when the reference count drops to zero.
100
 * This function handles the case when the reference count drops to zero.
101
 *
101
 *
102
 * @param node      VFS node that will have its refcnt decremented.
102
 * @param node      VFS node that will have its refcnt decremented.
103
 */
103
 */
104
void vfs_node_delref(vfs_node_t *node)
104
void vfs_node_delref(vfs_node_t *node)
105
{
105
{
106
    bool free_vfs_node = false;
106
    bool free_vfs_node = false;
107
    bool free_fs_node = false;
107
    bool free_fs_node = false;
108
 
108
 
109
    futex_down(&nodes_futex);
109
    futex_down(&nodes_futex);
110
    if (node->refcnt-- == 1) {
110
    if (node->refcnt-- == 1) {
111
        /*
111
        /*
112
         * We are dropping the last reference to this node.
112
         * We are dropping the last reference to this node.
113
         * Remove it from the VFS node hash table.
113
         * Remove it from the VFS node hash table.
114
         */
114
         */
115
        unsigned long key[] = {
115
        unsigned long key[] = {
116
            [KEY_FS_HANDLE] = node->fs_handle,
116
            [KEY_FS_HANDLE] = node->fs_handle,
117
            [KEY_DEV_HANDLE] = node->dev_handle,
117
            [KEY_DEV_HANDLE] = node->dev_handle,
118
            [KEY_INDEX] = node->index
118
            [KEY_INDEX] = node->index
119
        };
119
        };
120
        hash_table_remove(&nodes, key, 3);
120
        hash_table_remove(&nodes, key, 3);
121
        free_vfs_node = true;
121
        free_vfs_node = true;
122
        if (!node->lnkcnt)
122
        if (!node->lnkcnt)
123
            free_fs_node = true;
123
            free_fs_node = true;
124
    }
124
    }
125
    futex_up(&nodes_futex);
125
    futex_up(&nodes_futex);
126
 
126
 
127
    if (free_fs_node) {
127
    if (free_fs_node) {
128
        /*
128
        /*
129
         * The node is not visible in the file system namespace.
129
         * The node is not visible in the file system namespace.
130
         * Free up its resources.
130
         * Free up its resources.
131
         */
131
         */
132
        int phone = vfs_grab_phone(node->fs_handle);
132
        int phone = vfs_grab_phone(node->fs_handle);
133
        ipcarg_t rc;
133
        ipcarg_t rc;
134
        rc = async_req_2_0(phone, VFS_FREE, (ipcarg_t)node->dev_handle,
134
        rc = async_req_2_0(phone, VFS_DESTROY,
135
            (ipcarg_t)node->index);
135
            (ipcarg_t)node->dev_handle, (ipcarg_t)node->index);
136
        assert(rc == EOK);
136
        assert(rc == EOK);
137
        vfs_release_phone(phone);
137
        vfs_release_phone(phone);
138
    }
138
    }
139
    if (free_vfs_node)
139
    if (free_vfs_node)
140
        free(node);
140
        free(node);
141
}
141
}
142
 
142
 
143
/** Find VFS node.
143
/** Find VFS node.
144
 *
144
 *
145
 * This function will try to lookup the given triplet in the VFS node hash
145
 * This function will try to lookup the given triplet in the VFS node hash
146
 * table. In case the triplet is not found there, a new VFS node is created.
146
 * table. In case the triplet is not found there, a new VFS node is created.
147
 * In any case, the VFS node will have its reference count incremented. Every
147
 * In any case, the VFS node will have its reference count incremented. Every
148
 * node returned by this call should be eventually put back by calling
148
 * node returned by this call should be eventually put back by calling
149
 * vfs_node_put() on it.
149
 * vfs_node_put() on it.
150
 *
150
 *
151
 * @param result    Populated lookup result structure.
151
 * @param result    Populated lookup result structure.
152
 *
152
 *
153
 * @return      VFS node corresponding to the given triplet.
153
 * @return      VFS node corresponding to the given triplet.
154
 */
154
 */
155
vfs_node_t *vfs_node_get(vfs_lookup_res_t *result)
155
vfs_node_t *vfs_node_get(vfs_lookup_res_t *result)
156
{
156
{
157
    unsigned long key[] = {
157
    unsigned long key[] = {
158
        [KEY_FS_HANDLE] = result->triplet.fs_handle,
158
        [KEY_FS_HANDLE] = result->triplet.fs_handle,
159
        [KEY_DEV_HANDLE] = result->triplet.dev_handle,
159
        [KEY_DEV_HANDLE] = result->triplet.dev_handle,
160
        [KEY_INDEX] = result->triplet.index
160
        [KEY_INDEX] = result->triplet.index
161
    };
161
    };
162
    link_t *tmp;
162
    link_t *tmp;
163
    vfs_node_t *node;
163
    vfs_node_t *node;
164
 
164
 
165
    futex_down(&nodes_futex);
165
    futex_down(&nodes_futex);
166
    tmp = hash_table_find(&nodes, key);
166
    tmp = hash_table_find(&nodes, key);
167
    if (!tmp) {
167
    if (!tmp) {
168
        node = (vfs_node_t *) malloc(sizeof(vfs_node_t));
168
        node = (vfs_node_t *) malloc(sizeof(vfs_node_t));
169
        if (!node) {
169
        if (!node) {
170
            futex_up(&nodes_futex);
170
            futex_up(&nodes_futex);
171
            return NULL;
171
            return NULL;
172
        }
172
        }
173
        memset(node, 0, sizeof(vfs_node_t));
173
        memset(node, 0, sizeof(vfs_node_t));
174
        node->fs_handle = result->triplet.fs_handle;
174
        node->fs_handle = result->triplet.fs_handle;
175
        node->dev_handle = result->triplet.dev_handle;
175
        node->dev_handle = result->triplet.dev_handle;
176
        node->index = result->triplet.index;
176
        node->index = result->triplet.index;
177
        node->size = result->size;
177
        node->size = result->size;
178
        node->lnkcnt = result->lnkcnt;
178
        node->lnkcnt = result->lnkcnt;
179
        link_initialize(&node->nh_link);
179
        link_initialize(&node->nh_link);
180
        rwlock_initialize(&node->contents_rwlock);
180
        rwlock_initialize(&node->contents_rwlock);
181
        hash_table_insert(&nodes, key, &node->nh_link);
181
        hash_table_insert(&nodes, key, &node->nh_link);
182
    } else {
182
    } else {
183
        node = hash_table_get_instance(tmp, vfs_node_t, nh_link);  
183
        node = hash_table_get_instance(tmp, vfs_node_t, nh_link);  
184
    }
184
    }
185
 
185
 
186
    assert(node->size == result->size);
186
    assert(node->size == result->size);
187
    assert(node->lnkcnt == result->lnkcnt);
187
    assert(node->lnkcnt == result->lnkcnt);
188
 
188
 
189
    _vfs_node_addref(node);
189
    _vfs_node_addref(node);
190
    futex_up(&nodes_futex);
190
    futex_up(&nodes_futex);
191
 
191
 
192
    return node;
192
    return node;
193
}
193
}
194
 
194
 
195
/** Return VFS node when no longer needed by the caller.
195
/** Return VFS node when no longer needed by the caller.
196
 *
196
 *
197
 * This function will remove the reference on the VFS node created by
197
 * This function will remove the reference on the VFS node created by
198
 * vfs_node_get(). This function can only be called as a closing bracket to the
198
 * vfs_node_get(). This function can only be called as a closing bracket to the
199
 * preceding vfs_node_get() call.
199
 * preceding vfs_node_get() call.
200
 *
200
 *
201
 * @param node      VFS node being released.
201
 * @param node      VFS node being released.
202
 */
202
 */
203
void vfs_node_put(vfs_node_t *node)
203
void vfs_node_put(vfs_node_t *node)
204
{
204
{
205
    vfs_node_delref(node);
205
    vfs_node_delref(node);
206
}
206
}
207
 
207
 
208
hash_index_t nodes_hash(unsigned long key[])
208
hash_index_t nodes_hash(unsigned long key[])
209
{
209
{
210
    hash_index_t a = key[KEY_FS_HANDLE] << (NODES_BUCKETS_LOG / 4);
210
    hash_index_t a = key[KEY_FS_HANDLE] << (NODES_BUCKETS_LOG / 4);
211
    hash_index_t b = (a | key[KEY_DEV_HANDLE]) << (NODES_BUCKETS_LOG / 2);
211
    hash_index_t b = (a | key[KEY_DEV_HANDLE]) << (NODES_BUCKETS_LOG / 2);
212
   
212
   
213
    return (b | key[KEY_INDEX]) & (NODES_BUCKETS - 1);
213
    return (b | key[KEY_INDEX]) & (NODES_BUCKETS - 1);
214
}
214
}
215
 
215
 
216
int nodes_compare(unsigned long key[], hash_count_t keys, link_t *item)
216
int nodes_compare(unsigned long key[], hash_count_t keys, link_t *item)
217
{
217
{
218
    vfs_node_t *node = hash_table_get_instance(item, vfs_node_t, nh_link);
218
    vfs_node_t *node = hash_table_get_instance(item, vfs_node_t, nh_link);
219
    return (node->fs_handle == key[KEY_FS_HANDLE]) &&
219
    return (node->fs_handle == key[KEY_FS_HANDLE]) &&
220
        (node->dev_handle == key[KEY_DEV_HANDLE]) &&
220
        (node->dev_handle == key[KEY_DEV_HANDLE]) &&
221
        (node->index == key[KEY_INDEX]);
221
        (node->index == key[KEY_INDEX]);
222
}
222
}
223
 
223
 
224
void nodes_remove_callback(link_t *item)
224
void nodes_remove_callback(link_t *item)
225
{
225
{
226
}
226
}
227
 
227
 
228
/**
228
/**
229
 * @}
229
 * @}
230
 */
230
 */
231
 
231