WebSVN – HelenOS – Diff – /branches/dd/uspace/srv/fs/fat/fat_idx.c

 static futex_t unused_futex = FUTEX_INITIALIZER;
 /** List of unused structures. */
 static LIST_INITIALIZE(unused_head);
+static void unused_initialize(unused_t *u, dev_handle_t dev_handle)
+{
+    link_initialize(&u->link);
+    u->dev_handle = dev_handle;
+    u->next = 0;
+    u->remaining = ((uint64_t)((fs_index_t)-1)) + 1;
+    list_initialize(&u->freed_head);
+}
+static unused_t *unused_find(dev_handle_t dev_handle, bool lock)
+{
+    unused_t *u;
+    link_t *l;
+    if (lock)
+        futex_down(&unused_futex);
+    for (l = unused_head.next; l != &unused_head; l = l->next) {
+        u = list_get_instance(l, unused_t, link);
+        if (u->dev_handle == dev_handle)
+            return u;
+    }
+    if (lock)
+        futex_up(&unused_futex);
+    return NULL;
+}
 /** Futex protecting the up_hash and ui_hash. */
 static futex_t used_futex = FUTEX_INITIALIZER;
 /**
  * Global hash table of all used fat_idx_t structures.
     .compare = idx_compare,
     .remove_callback = idx_remove_callback,
 };
 /** Allocate a VFS index which is not currently in use. */
-static bool fat_idx_alloc(dev_handle_t dev_handle, fs_index_t *index)
+static bool fat_index_alloc(dev_handle_t dev_handle, fs_index_t *index)
+{
-    link_t *l;
     unused_t *u;
     assert(index);
-    futex_down(&unused_futex);
-    for (l = unused_head.next; l != &unused_head; l = l->next) {
-        u = list_get_instance(l, unused_t, link);
-        if (u->dev_handle == dev_handle)
+    u = unused_find(dev_handle, true);
-            goto hit;
+    if (!u)
-    }
-    futex_up(&unused_futex);
-    /* dev_handle not found */
-    return false;
+        return false;
-hit:
     if (list_empty(&u->freed_head)) {
         if (u->remaining) {
             /*
              * There are no freed indices, allocate one directly
              * from the counter.
+        }
+    }
+}
 /** Free a VFS index, which is no longer in use. */
-static void fat_idx_free(dev_handle_t dev_handle, fs_index_t index)
+static void fat_index_free(dev_handle_t dev_handle, fs_index_t index)
+{
-    link_t *l;
     unused_t *u;
-    futex_down(&unused_futex);
-    for (l = unused_head.next; l != &unused_head; l = l->next) {
-        u = list_get_instance(l, unused_t, link);
-        if (u->dev_handle == dev_handle)
+    u = unused_find(dev_handle, true);
-            goto hit;
-    }
-    futex_up(&unused_futex);
-    /* should not happen */
-    assert(0);
+    assert(u);
-hit:
     if (u->next == index + 1) {
         /* The index can be returned directly to the counter. */
         u->next--;
         u->remaining++;
     } else {
         list_append(&n->link, &u->freed_head);
+    }
     futex_up(&unused_futex);
+}
+static fat_idx_t *fat_idx_create(dev_handle_t dev_handle)
+{
+    fat_idx_t *fidx;
+    fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t));
+    if (!fidx)
+        return NULL;
+    if (!fat_index_alloc(dev_handle, &fidx->index)) {
+        free(fidx);
+        return NULL;
+    }
+    link_initialize(&fidx->uph_link);
+    link_initialize(&fidx->uih_link);
+    futex_initialize(&fidx->lock, 1);
+    fidx->dev_handle = dev_handle;
+    fidx->pfc = FAT_CLST_RES0;  /* no parent yet */
+    fidx->pdi = 0;
+    fidx->nodep = NULL;
+    return fidx;
+}
+fat_idx_t *fat_idx_get_new(dev_handle_t dev_handle)
+{
+    fat_idx_t *fidx;
+    futex_down(&used_futex);
+    fidx = fat_idx_create(dev_handle);
+    if (!fidx) {
+        futex_up(&used_futex);
+        return NULL;
+    }
+    unsigned long ikey[] = {
+        [UIH_DH_KEY] = dev_handle,
+        [UIH_INDEX_KEY] = fidx->index,
+    };
+    hash_table_insert(&ui_hash, ikey, &fidx->uih_link);
+    futex_down(&fidx->lock);
+    futex_up(&used_futex);
+    return fidx;
+}
 fat_idx_t *
 fat_idx_get_by_pos(dev_handle_t dev_handle, fat_cluster_t pfc, unsigned pdi)
+{
     fat_idx_t *fidx;
     link_t *l;
     futex_down(&used_futex);
     l = hash_table_find(&up_hash, pkey);
     if (l) {
         fidx = hash_table_get_instance(l, fat_idx_t, uph_link);
     } else {
-        fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t));
+        fidx = fat_idx_create(dev_handle);
         if (!fidx) {
             futex_up(&used_futex);
             return NULL;
+        }
-        if (!fat_idx_alloc(dev_handle, &fidx->index)) {
-            free(fidx);
-            futex_up(&used_futex);
-            return NULL;
-        }
         unsigned long ikey[] = {
             [UIH_DH_KEY] = dev_handle,
             [UIH_INDEX_KEY] = fidx->index,
         };
-        link_initialize(&fidx->uph_link);
-        link_initialize(&fidx->uih_link);
-        futex_initialize(&fidx->lock, 1);
-        fidx->dev_handle = dev_handle;
         fidx->pfc = pfc;
         fidx->pdi = pdi;
-        fidx->nodep = NULL;
         hash_table_insert(&up_hash, pkey, &fidx->uph_link);
         hash_table_insert(&ui_hash, ikey, &fidx->uih_link);
+    }
     futex_down(&fidx->lock);
     futex_up(&used_futex);
     return fidx;
+}
+void fat_idx_hashin(fat_idx_t *idx)
+{
+    unsigned long pkey[] = {
+        [UPH_DH_KEY] = idx->dev_handle,
+        [UPH_PFC_KEY] = idx->pfc,
+        [UPH_PDI_KEY] = idx->pdi,
+    };
+    futex_down(&used_futex);
+    hash_table_insert(&up_hash, pkey, &idx->uph_link);
+    futex_up(&used_futex);
+}
+void fat_idx_hashout(fat_idx_t *idx)
+{
+    unsigned long pkey[] = {
+        [UPH_DH_KEY] = idx->dev_handle,
+        [UPH_PFC_KEY] = idx->pfc,
+        [UPH_PDI_KEY] = idx->pdi,
+    };
+    futex_down(&used_futex);
+    hash_table_remove(&up_hash, pkey, 3);
+    futex_up(&used_futex);
+}
 fat_idx_t *
 fat_idx_get_by_index(dev_handle_t dev_handle, fs_index_t index)
+{
     fat_idx_t *fidx = NULL;
     link_t *l;
     futex_up(&used_futex);
     return fidx;
+}
+/** Destroy the index structure.
+ *
+ * @param idx       The index structure to be destroyed.
+ */
+void fat_idx_destroy(fat_idx_t *idx)
+{
+    unsigned long ikey[] = {
+        [UIH_DH_KEY] = idx->dev_handle,
+        [UIH_INDEX_KEY] = idx->index,
+    };
+    assert(idx->pfc == FAT_CLST_RES0);
+    futex_down(&used_futex);
+    /*
+     * Since we can only free unlinked nodes, the index structure is not
+     * present in the position hash (uph). We therefore hash it out from
+     * the index hash only.
+     */
+    hash_table_remove(&ui_hash, ikey, 2);
+    futex_up(&used_futex);
+    /* Release the VFS index. */
+    fat_index_free(idx->dev_handle, idx->index);
+    /* Deallocate the structure. */
+    free(idx);
+}
+int fat_idx_init(void)
+{
+    if (!hash_table_create(&up_hash, UPH_BUCKETS, 3, &uph_ops))
+        return ENOMEM;
+    if (!hash_table_create(&ui_hash, UIH_BUCKETS, 2, &uih_ops)) {
+        hash_table_destroy(&up_hash);
+        return ENOMEM;
+    }
+    return EOK;
+}
+void fat_idx_fini(void)
+{
+    /* We assume the hash tables are empty. */
+    hash_table_destroy(&up_hash);
+    hash_table_destroy(&ui_hash);
+}
+int fat_idx_init_by_dev_handle(dev_handle_t dev_handle)
+{
+    unused_t *u;
+    int rc = EOK;
+    u = (unused_t *) malloc(sizeof(unused_t));
+    if (!u)
+        return ENOMEM;
+    unused_initialize(u, dev_handle);
+    futex_down(&unused_futex);
+    if (!unused_find(dev_handle, false))
+        list_append(&u->link, &unused_head);
+    else
+        rc = EEXIST;
+    futex_up(&unused_futex);
+    return rc;
+}
+void fat_idx_fini_by_dev_handle(dev_handle_t dev_handle)
+{
+    unused_t *u;
+    u = unused_find(dev_handle, true);
+    assert(u);
+    list_remove(&u->link);
+    futex_up(&unused_futex);
+    while (!list_empty(&u->freed_head)) {
+        freed_t *f;
+        f = list_get_instance(u->freed_head.next, freed_t, link);
+        list_remove(&f->link);
+        free(f);
+    }
+    free(u);
+}
+/**
+ * @}
+ */

Subversion Repositories HelenOS

(root)/branches/dd/uspace/srv/fs/fat/fat_idx.c – Rev 3022 → 4055