WebSVN – HelenOS – Diff – /branches/network/uspace/srv/vfs/vfs_node.c


/*
 * Copyright (c) 2008 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/** @addtogroup fs
 * @{
 */
 
/**
 * @file    vfs_node.c
 * @brief   Various operations on VFS nodes have their home in this file.
 */
 
#include "vfs.h"
#include <stdlib.h>
#include <string.h>
#include <atomic.h>
#include <futex.h>
#include <rwlock.h>
#include <libadt/hash_table.h>
#include <assert.h>
#include <async.h>
#include <errno.h>
 
/** Futex protecting the VFS node hash table. */
atomic_t nodes_futex = FUTEX_INITIALIZER;
 
#define NODES_BUCKETS_LOG   8
#define NODES_BUCKETS       (1 << NODES_BUCKETS_LOG)
 
/** VFS node hash table containing all active, in-memory VFS nodes. */
hash_table_t nodes;
 
#define KEY_FS_HANDLE   0
#define KEY_DEV_HANDLE  1
#define KEY_INDEX   2
 
static hash_index_t nodes_hash(unsigned long []);
static int nodes_compare(unsigned long [], hash_count_t, link_t *);
static void nodes_remove_callback(link_t *);
 
/** VFS node hash table operations. */
hash_table_operations_t nodes_ops = {
    .hash = nodes_hash,
    .compare = nodes_compare,
    .remove_callback = nodes_remove_callback
};
 
/** Initialize the VFS node hash table.
 *
 * @return      Return true on success, false on failure.
 */
bool vfs_nodes_init(void)
{
    return hash_table_create(&nodes, NODES_BUCKETS, 3, &nodes_ops);
}
 
static inline void _vfs_node_addref(vfs_node_t *node)
{
    node->refcnt++;
}
 
/** Increment reference count of a VFS node.
 *
 * @param node      VFS node that will have its refcnt incremented.
 */
void vfs_node_addref(vfs_node_t *node)
{
    futex_down(&nodes_futex);
    _vfs_node_addref(node);
    futex_up(&nodes_futex);
}
 
/** Decrement reference count of a VFS node.
 *
 * This function handles the case when the reference count drops to zero.
 *
 * @param node      VFS node that will have its refcnt decremented.
 */
void vfs_node_delref(vfs_node_t *node)
{
    bool free_vfs_node = false;
    bool free_fs_node = false;
 
    futex_down(&nodes_futex);
    if (node->refcnt-- == 1) {
        /*
         * We are dropping the last reference to this node.
         * Remove it from the VFS node hash table.
         */
        unsigned long key[] = {
            [KEY_FS_HANDLE] = node->fs_handle,
            [KEY_DEV_HANDLE] = node->dev_handle,
            [KEY_INDEX] = node->index
        };
        hash_table_remove(&nodes, key, 3);
        free_vfs_node = true;
        if (!node->lnkcnt)
            free_fs_node = true;
    }
    futex_up(&nodes_futex);
 
    if (free_fs_node) {
        /*
         * The node is not visible in the file system namespace.
         * Free up its resources.
         */
        int phone = vfs_grab_phone(node->fs_handle);
        ipcarg_t rc;
        rc = async_req_2_0(phone, VFS_FREE, (ipcarg_t)node->dev_handle,
            (ipcarg_t)node->index);
        assert(rc == EOK);
        vfs_release_phone(phone);
    }
    if (free_vfs_node)
        free(node);
}
 
/** Find VFS node.
 *
 * This function will try to lookup the given triplet in the VFS node hash
 * table. In case the triplet is not found there, a new VFS node is created.
 * In any case, the VFS node will have its reference count incremented. Every
 * node returned by this call should be eventually put back by calling
 * vfs_node_put() on it.
 *
 * @param result    Populated lookup result structure.
 *
 * @return      VFS node corresponding to the given triplet.
 */
vfs_node_t *vfs_node_get(vfs_lookup_res_t *result)
{
    unsigned long key[] = {
        [KEY_FS_HANDLE] = result->triplet.fs_handle,
        [KEY_DEV_HANDLE] = result->triplet.dev_handle,
        [KEY_INDEX] = result->triplet.index
    };
    link_t *tmp;
    vfs_node_t *node;
 
    futex_down(&nodes_futex);
    tmp = hash_table_find(&nodes, key);
    if (!tmp) {
        node = (vfs_node_t *) malloc(sizeof(vfs_node_t));
        if (!node) {
            futex_up(&nodes_futex);
            return NULL;
        }
        memset(node, 0, sizeof(vfs_node_t));
        node->fs_handle = result->triplet.fs_handle;
        node->dev_handle = result->triplet.fs_handle;
        node->index = result->triplet.index;
        node->size = result->size;
        node->lnkcnt = result->lnkcnt;
        link_initialize(&node->nh_link);
        rwlock_initialize(&node->contents_rwlock);
        hash_table_insert(&nodes, key, &node->nh_link);
    } else {
        node = hash_table_get_instance(tmp, vfs_node_t, nh_link);  
    }
 
    assert(node->size == result->size);
    assert(node->lnkcnt == result->lnkcnt);
 
    _vfs_node_addref(node);
    futex_up(&nodes_futex);
 
    return node;
}
 
/** Return VFS node when no longer needed by the caller.
 *
 * This function will remove the reference on the VFS node created by
 * vfs_node_get(). This function can only be called as a closing bracket to the
 * preceding vfs_node_get() call.
 *
 * @param node      VFS node being released.
 */
void vfs_node_put(vfs_node_t *node)
{
    vfs_node_delref(node);
}
 
hash_index_t nodes_hash(unsigned long key[])
{
    hash_index_t a = key[KEY_FS_HANDLE] << (NODES_BUCKETS_LOG / 4);
    hash_index_t b = (a | key[KEY_DEV_HANDLE]) << (NODES_BUCKETS_LOG / 2);
   
    return (b | key[KEY_INDEX]) & (NODES_BUCKETS - 1);
}
 
int nodes_compare(unsigned long key[], hash_count_t keys, link_t *item)
{
    vfs_node_t *node = hash_table_get_instance(item, vfs_node_t, nh_link);
    return (node->fs_handle == key[KEY_FS_HANDLE]) &&
        (node->dev_handle == key[KEY_DEV_HANDLE]) &&
        (node->index == key[KEY_INDEX]);
}
 
void nodes_remove_callback(link_t *item)
{
 
 
}
 
/**
 * @}
 */
 

Rev 2730	Rev 2731
1	/*	1	/*
2	* Copyright (c) 2008 Jakub Jermar	2	* Copyright (c) 2008 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup fs	29	/** @addtogroup fs
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file vfs_node.c	34	* @file vfs_node.c
35	* @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>
-		47	#include <errno.h>
46		48
47	/** Futex protecting the VFS node hash table. */	49	/** Futex protecting the VFS node hash table. */
48	atomic_t nodes_futex = FUTEX_INITIALIZER;	50	atomic_t nodes_futex = FUTEX_INITIALIZER;
49		51
50	#define NODES_BUCKETS_LOG 8	52	#define NODES_BUCKETS_LOG 8
51	#define NODES_BUCKETS (1 << NODES_BUCKETS_LOG)	53	#define NODES_BUCKETS (1 << NODES_BUCKETS_LOG)
52		54
53	/** VFS node hash table containing all active, in-memory VFS nodes. */	55	/** VFS node hash table containing all active, in-memory VFS nodes. */
54	hash_table_t nodes;	56	hash_table_t nodes;
55		57
56	#define KEY_FS_HANDLE 0	58	#define KEY_FS_HANDLE 0
57	#define KEY_DEV_HANDLE 1	59	#define KEY_DEV_HANDLE 1
58	#define KEY_INDEX 2	60	#define KEY_INDEX 2
59		61
60	static hash_index_t nodes_hash(unsigned long []);	62	static hash_index_t nodes_hash(unsigned long []);
61	static int nodes_compare(unsigned long [], hash_count_t, link_t *);	63	static int nodes_compare(unsigned long [], hash_count_t, link_t *);
62	static void nodes_remove_callback(link_t *);	64	static void nodes_remove_callback(link_t *);
63		65
64	/** VFS node hash table operations. */	66	/** VFS node hash table operations. */
65	hash_table_operations_t nodes_ops = {	67	hash_table_operations_t nodes_ops = {
66	.hash = nodes_hash,	68	.hash = nodes_hash,
67	.compare = nodes_compare,	69	.compare = nodes_compare,
68	.remove_callback = nodes_remove_callback	70	.remove_callback = nodes_remove_callback
69	};	71	};
70		72
71	/** Initialize the VFS node hash table.	73	/** Initialize the VFS node hash table.
72	*	74	*
73	* @return Return true on success, false on failure.	75	* @return Return true on success, false on failure.
74	*/	76	*/
75	bool vfs_nodes_init(void)	77	bool vfs_nodes_init(void)
76	{	78	{
77	return hash_table_create(&nodes, NODES_BUCKETS, 3, &nodes_ops);	79	return hash_table_create(&nodes, NODES_BUCKETS, 3, &nodes_ops);
78	}	80	}
79		81
80	static inline void _vfs_node_addref(vfs_node_t *node)	82	static inline void _vfs_node_addref(vfs_node_t *node)
81	{	83	{
82	node->refcnt++;	84	node->refcnt++;
83	}	85	}
84		86
85	/** Increment reference count of a VFS node.	87	/** Increment reference count of a VFS node.
86	*	88	*
87	* @param node VFS node that will have its refcnt incremented.	89	* @param node VFS node that will have its refcnt incremented.
88	*/	90	*/
89	void vfs_node_addref(vfs_node_t *node)	91	void vfs_node_addref(vfs_node_t *node)
90	{	92	{
91	futex_down(&nodes_futex);	93	futex_down(&nodes_futex);
92	_vfs_node_addref(node);	94	_vfs_node_addref(node);
93	futex_up(&nodes_futex);	95	futex_up(&nodes_futex);
94	}	96	}
95		97
96	/** Decrement reference count of a VFS node.	98	/** Decrement reference count of a VFS node.
97	*	99	*
98	* 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.
99	*	101	*
100	* @param node VFS node that will have its refcnt decremented.	102	* @param node VFS node that will have its refcnt decremented.
101	*/	103	*/
102	void vfs_node_delref(vfs_node_t *node)	104	void vfs_node_delref(vfs_node_t *node)
103	{	105	{
-		106	bool free_vfs_node = false;
-		107	bool free_fs_node = false;
-		108
104	futex_down(&nodes_futex);	109	futex_down(&nodes_futex);
105	if (node->refcnt-- == 1) {	110	if (node->refcnt-- == 1) {
-		111	/*
-		112	* We are dropping the last reference to this node.
-		113	* Remove it from the VFS node hash table.
-		114	*/
106	unsigned long key[] = {	115	unsigned long key[] = {
107	[KEY_FS_HANDLE] = node->fs_handle,	116	[KEY_FS_HANDLE] = node->fs_handle,
108	[KEY_DEV_HANDLE] = node->dev_handle,	117	[KEY_DEV_HANDLE] = node->dev_handle,
109	[KEY_INDEX] = node->index	118	[KEY_INDEX] = node->index
110	};	119	};
111	hash_table_remove(&nodes, key, 3);	120	hash_table_remove(&nodes, key, 3);
-		121	free_vfs_node = true;
-		122	if (!node->lnkcnt)
-		123	free_fs_node = true;
112	}	124	}
113	futex_up(&nodes_futex);	125	futex_up(&nodes_futex);
-		126
-		127	if (free_fs_node) {
-		128	/*
-		129	* The node is not visible in the file system namespace.
-		130	* Free up its resources.
-		131	*/
-		132	int phone = vfs_grab_phone(node->fs_handle);
-		133	ipcarg_t rc;
-		134	rc = async_req_2_0(phone, VFS_FREE, (ipcarg_t)node->dev_handle,
-		135	(ipcarg_t)node->index);
-		136	assert(rc == EOK);
-		137	vfs_release_phone(phone);
-		138	}
-		139	if (free_vfs_node)
-		140	free(node);
114	}	141	}
115		142
116	/** Find VFS node.	143	/** Find VFS node.
117	*	144	*
118	* 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
119	* 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.
120	* 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
121	* 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
122	* vfs_node_put() on it.	149	* vfs_node_put() on it.
123	*	150	*
124	* @param result Populated lookup result structure.	151	* @param result Populated lookup result structure.
125	*	152	*
126	* @return VFS node corresponding to the given triplet.	153	* @return VFS node corresponding to the given triplet.
127	*/	154	*/
128	vfs_node_t vfs_node_get(vfs_lookup_res_t result)	155	vfs_node_t vfs_node_get(vfs_lookup_res_t result)
129	{	156	{
130	unsigned long key[] = {	157	unsigned long key[] = {
131	[KEY_FS_HANDLE] = result->triplet.fs_handle,	158	[KEY_FS_HANDLE] = result->triplet.fs_handle,
132	[KEY_DEV_HANDLE] = result->triplet.dev_handle,	159	[KEY_DEV_HANDLE] = result->triplet.dev_handle,
133	[KEY_INDEX] = result->triplet.index	160	[KEY_INDEX] = result->triplet.index
134	};	161	};
135	link_t *tmp;	162	link_t *tmp;
136	vfs_node_t *node;	163	vfs_node_t *node;
137		164
138	futex_down(&nodes_futex);	165	futex_down(&nodes_futex);
139	tmp = hash_table_find(&nodes, key);	166	tmp = hash_table_find(&nodes, key);
140	if (!tmp) {	167	if (!tmp) {
141	node = (vfs_node_t *) malloc(sizeof(vfs_node_t));	168	node = (vfs_node_t *) malloc(sizeof(vfs_node_t));
142	if (!node) {	169	if (!node) {
143	futex_up(&nodes_futex);	170	futex_up(&nodes_futex);
144	return NULL;	171	return NULL;
145	}	172	}
146	memset(node, 0, sizeof(vfs_node_t));	173	memset(node, 0, sizeof(vfs_node_t));
147	node->fs_handle = result->triplet.fs_handle;	174	node->fs_handle = result->triplet.fs_handle;
148	node->dev_handle = result->triplet.fs_handle;	175	node->dev_handle = result->triplet.fs_handle;
149	node->index = result->triplet.index;	176	node->index = result->triplet.index;
150	node->size = result->size;	177	node->size = result->size;
151	node->lnkcnt = result->lnkcnt;	178	node->lnkcnt = result->lnkcnt;
152	link_initialize(&node->nh_link);	179	link_initialize(&node->nh_link);
153	rwlock_initialize(&node->contents_rwlock);	180	rwlock_initialize(&node->contents_rwlock);
154	hash_table_insert(&nodes, key, &node->nh_link);	181	hash_table_insert(&nodes, key, &node->nh_link);
155	} else {	182	} else {
156	node = hash_table_get_instance(tmp, vfs_node_t, nh_link);	183	node = hash_table_get_instance(tmp, vfs_node_t, nh_link);
157	}	184	}
158		185
159	assert(node->size == result->size);	186	assert(node->size == result->size);
160	assert(node->lnkcnt == result->lnkcnt);	187	assert(node->lnkcnt == result->lnkcnt);
161		188
162	_vfs_node_addref(node);	189	_vfs_node_addref(node);
163	futex_up(&nodes_futex);	190	futex_up(&nodes_futex);
164		191
165	return node;	192	return node;
166	}	193	}
167		194
168	/** Return VFS node when no longer needed by the caller.	195	/** Return VFS node when no longer needed by the caller.
169	*	196	*
170	* 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
171	* 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
172	* preceding vfs_node_get() call.	199	* preceding vfs_node_get() call.
173	*	200	*
174	* @param node VFS node being released.	201	* @param node VFS node being released.
175	*/	202	*/
176	void vfs_node_put(vfs_node_t *node)	203	void vfs_node_put(vfs_node_t *node)
177	{	204	{
178	vfs_node_delref(node);	205	vfs_node_delref(node);
179	}	206	}
180		207
181	hash_index_t nodes_hash(unsigned long key[])	208	hash_index_t nodes_hash(unsigned long key[])
182	{	209	{
183	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);
184	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);
185		212
186	return (b \| key[KEY_INDEX]) & (NODES_BUCKETS - 1);	213	return (b \| key[KEY_INDEX]) & (NODES_BUCKETS - 1);
187	}	214	}
188		215
189	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)
190	{	217	{
191	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);
192	return (node->fs_handle == key[KEY_FS_HANDLE]) &&	219	return (node->fs_handle == key[KEY_FS_HANDLE]) &&
193	(node->dev_handle == key[KEY_DEV_HANDLE]) &&	220	(node->dev_handle == key[KEY_DEV_HANDLE]) &&
194	(node->index == key[KEY_INDEX]);	221	(node->index == key[KEY_INDEX]);
195	}	222	}
196		223
197	void nodes_remove_callback(link_t *item)	224	void nodes_remove_callback(link_t *item)
198	{	225	{
199	vfs_node_t *node = hash_table_get_instance(item, vfs_node_t, nh_link);	-
200	free(node);	-
201	}	226	}
202		227
203	/**	228	/**
204	* @}	229	* @}
205	*/	230	*/
206		231

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(root)/branches/network/uspace/srv/vfs/vfs_node.c @ 4718 – Rev 2730 → 2731