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 */
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 */
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#include "vfs.h"
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#include "vfs.h"
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#include <stdlib.h>
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#include <stdlib.h>
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#include <string.h>
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#include <string.h>
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#include <futex.h>
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#include <rwlock.h>
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#include <fibril_sync.h>
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#include <libadt/hash_table.h>
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#include <adt/hash_table.h>
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#include <assert.h>
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#include <assert.h>
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#include <async.h>
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#include <async.h>
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#include <errno.h>
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#include <errno.h>
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/** Futex protecting the VFS node hash table. */
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/** Mutex protecting the VFS node hash table. */
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futex_t nodes_futex = FUTEX_INITIALIZER;
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FIBRIL_MUTEX_INITIALIZE(nodes_mutex);
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#define NODES_BUCKETS_LOG   8
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#define NODES_BUCKETS_LOG   8
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#define NODES_BUCKETS       (1 << NODES_BUCKETS_LOG)
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#define NODES_BUCKETS       (1 << NODES_BUCKETS_LOG)
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/** VFS node hash table containing all active, in-memory VFS nodes. */
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/** VFS node hash table containing all active, in-memory VFS nodes. */
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 *
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 *
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 * @param node      VFS node that will have its refcnt incremented.
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 * @param node      VFS node that will have its refcnt incremented.
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 */
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 */
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void vfs_node_addref(vfs_node_t *node)
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void vfs_node_addref(vfs_node_t *node)
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{
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{
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    futex_down(&nodes_futex);
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    fibril_mutex_lock(&nodes_mutex);
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    _vfs_node_addref(node);
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    _vfs_node_addref(node);
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    futex_up(&nodes_futex);
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    fibril_mutex_unlock(&nodes_mutex);
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}
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}
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/** Decrement reference count of a VFS node.
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/** Decrement reference count of a VFS node.
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 *
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 *
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 * This function handles the case when the reference count drops to zero.
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 * This function handles the case when the reference count drops to zero.
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void vfs_node_delref(vfs_node_t *node)
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void vfs_node_delref(vfs_node_t *node)
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{
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{
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    bool free_vfs_node = false;
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    bool free_vfs_node = false;
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    bool free_fs_node = false;
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    bool free_fs_node = false;
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    futex_down(&nodes_futex);
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    fibril_mutex_lock(&nodes_mutex);
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    if (node->refcnt-- == 1) {
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    if (node->refcnt-- == 1) {
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        /*
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        /*
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         * We are dropping the last reference to this node.
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         * We are dropping the last reference to this node.
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         * Remove it from the VFS node hash table.
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         * Remove it from the VFS node hash table.
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         */
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         */
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        hash_table_remove(&nodes, key, 3);
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        hash_table_remove(&nodes, key, 3);
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        free_vfs_node = true;
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        free_vfs_node = true;
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        if (!node->lnkcnt)
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        if (!node->lnkcnt)
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            free_fs_node = true;
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            free_fs_node = true;
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    }
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    }
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    futex_up(&nodes_futex);
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    fibril_mutex_unlock(&nodes_mutex);
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    if (free_fs_node) {
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    if (free_fs_node) {
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        /*
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        /*
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         * The node is not visible in the file system namespace.
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         * The node is not visible in the file system namespace.
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         * Free up its resources.
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         * Free up its resources.
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        [KEY_INDEX] = result->triplet.index
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        [KEY_INDEX] = result->triplet.index
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    };
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    };
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    link_t *tmp;
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    link_t *tmp;
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    vfs_node_t *node;
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    vfs_node_t *node;
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    futex_down(&nodes_futex);
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    fibril_mutex_lock(&nodes_mutex);
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    tmp = hash_table_find(&nodes, key);
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    tmp = hash_table_find(&nodes, key);
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    if (!tmp) {
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    if (!tmp) {
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        node = (vfs_node_t *) malloc(sizeof(vfs_node_t));
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        node = (vfs_node_t *) malloc(sizeof(vfs_node_t));
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        if (!node) {
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        if (!node) {
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            futex_up(&nodes_futex);
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            fibril_mutex_unlock(&nodes_mutex);
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            return NULL;
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            return NULL;
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        }
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        }
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        memset(node, 0, sizeof(vfs_node_t));
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        memset(node, 0, sizeof(vfs_node_t));
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        node->fs_handle = result->triplet.fs_handle;
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        node->fs_handle = result->triplet.fs_handle;
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        node->dev_handle = result->triplet.dev_handle;
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        node->dev_handle = result->triplet.dev_handle;
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        node->index = result->triplet.index;
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        node->index = result->triplet.index;
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        node->size = result->size;
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        node->size = result->size;
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        node->lnkcnt = result->lnkcnt;
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        node->lnkcnt = result->lnkcnt;
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        node->type = result->type;
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        node->type = result->type;
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        link_initialize(&node->nh_link);
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        link_initialize(&node->nh_link);
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        rwlock_initialize(&node->contents_rwlock);
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        fibril_rwlock_initialize(&node->contents_rwlock);
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        hash_table_insert(&nodes, key, &node->nh_link);
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        hash_table_insert(&nodes, key, &node->nh_link);
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    } else {
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    } else {
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        node = hash_table_get_instance(tmp, vfs_node_t, nh_link);  
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        node = hash_table_get_instance(tmp, vfs_node_t, nh_link);
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        if (node->type == VFS_NODE_UNKNOWN &&
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        if (node->type == VFS_NODE_UNKNOWN &&
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            result->type != VFS_NODE_UNKNOWN) {
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            result->type != VFS_NODE_UNKNOWN) {
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            /* Upgrade the node type. */
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            /* Upgrade the node type. */
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            node->type = result->type;
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            node->type = result->type;
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        }
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        }
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    assert(node->size == result->size);
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    assert(node->size == result->size);
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    assert(node->lnkcnt == result->lnkcnt);
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    assert(node->lnkcnt == result->lnkcnt);
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    assert(node->type == result->type || result->type == VFS_NODE_UNKNOWN);
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    assert(node->type == result->type || result->type == VFS_NODE_UNKNOWN);
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    _vfs_node_addref(node);
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    _vfs_node_addref(node);
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    futex_up(&nodes_futex);
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    fibril_mutex_unlock(&nodes_mutex);
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    return node;
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    return node;
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}
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}
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/** Return VFS node when no longer needed by the caller.
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/** Return VFS node when no longer needed by the caller.
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{
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{
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}
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}
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/**
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/**
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 * @}
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 * @}
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 */
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 */