36,7 → 36,50 |
*/ |
|
#include "vfs.h" |
#include <stdlib.h> |
#include <string.h> |
#include <atomic.h> |
#include <futex.h> |
#include <libadt/hash_table.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. |
43,7 → 86,9 |
*/ |
void vfs_node_addref(vfs_node_t *node) |
{ |
/* TODO */ |
futex_down(&nodes_futex); |
_vfs_node_addref(node); |
futex_up(&nodes_futex); |
} |
|
/** Decrement reference count of a VFS node. |
54,7 → 99,16 |
*/ |
void vfs_node_delref(vfs_node_t *node) |
{ |
/* TODO */ |
futex_down(&nodes_futex); |
if (node->refcnt-- == 1) { |
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); |
} |
futex_up(&nodes_futex); |
} |
|
/** Find VFS node. |
71,8 → 125,35 |
*/ |
vfs_node_t *vfs_node_get(vfs_triplet_t *triplet) |
{ |
/* TODO */ |
return NULL; |
unsigned long key[] = { |
[KEY_FS_HANDLE] = triplet->fs_handle, |
[KEY_DEV_HANDLE] = triplet->dev_handle, |
[KEY_INDEX] = 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 = triplet->fs_handle; |
node->dev_handle = triplet->fs_handle; |
node->index = triplet->index; |
link_initialize(&node->nh_link); |
hash_table_insert(&nodes, key, &node->nh_link); |
} else { |
node = hash_table_get_instance(tmp, vfs_node_t, nh_link); |
} |
_vfs_node_addref(node); |
futex_up(&nodes_futex); |
|
return node; |
} |
|
/** Return VFS node when no longer needed by the caller. |
88,6 → 169,28 |
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) |
{ |
vfs_node_t *node = hash_table_get_instance(item, vfs_node_t, nh_link); |
free(node); |
} |
|
/** |
* @} |
*/ |