Changeset b818cff in mainline

Timestamp:

2007-11-06T17:26:28Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

44358c1

Parents:

6537572

Message:

VFS work.
Implement VFS node hash table management.

Location:

uspace/srv/vfs

Files:

• vfs.c (modified) (1 diff)
• vfs.h (modified) (2 diffs)
• vfs_node.c (modified) (5 diffs)

uspace/srv/vfs/vfs.c

@@ -125 +125 @@
 
         /*
+         * Initialize VFS node hash table.
+         */
+        if (!vfs_nodes_init()) {
+                printf("Failed to initialize the VFS node hash table.\n");
+                return ENOMEM;
+        }
+
+        /*
          * Allocate and initialize the Path Lookup Buffer.
          */

uspace/srv/vfs/vfs.h

@@ -179 +179 @@
 extern int vfs_lookup_internal(char *, size_t, vfs_triplet_t *, vfs_pair_t *);
 
-
+extern bool vfs_nodes_init(void);
 extern vfs_node_t *vfs_node_get(vfs_triplet_t *);
 extern void vfs_node_put(vfs_node_t *);
+
+#define MAX_OPEN_FILES  128
 
 extern bool vfs_files_init(void);
@@ -194 +196 @@
 extern void vfs_node_delref(vfs_node_t *);
 
-#define MAX_OPEN_FILES  128     
-
 extern void vfs_register(ipc_callid_t, ipc_call_t *);
 extern void vfs_mount(ipc_callid_t, ipc_call_t *);

uspace/srv/vfs/vfs_node.c

@@ -37 +37 @@
 
 #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.
@@ -44 +87 @@
 void vfs_node_addref(vfs_node_t *node)
 {
-        /* TODO */
+        futex_down(&nodes_futex);
+        _vfs_node_addref(node);
+        futex_up(&nodes_futex);
 }
 
@@ -55 +100 @@
 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);
 }
 
@@ -72 +126 @@
 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;
 }
 
@@ -89 +170 @@
 }
 
+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);
+}
+
 /**
  * @}