[btr] Add a comment to btr_pool_available().

[paraslash.git] / buffer_tree.c

diff --git a/buffer_tree.c b/buffer_tree.c
index 40079c2ff9984f5207ad5f1cb0aeaaf78bf9dedc..4160646da483bff8c8b0eea6c754d05fe17cf895 100644 (file)
--- a/buffer_tree.c
+++ b/buffer_tree.c
@@ -100,6 +100,10 @@ size_t btr_pool_unused(struct btr_pool *btrp)
        return btr_pool_size(btrp) - btr_pool_filled(btrp);
 }
 
+/*
+ * Return maximal size available for one read. This is
+ * smaller than the value returned by btr_pool_unused().
+ */
 size_t btr_pool_available(struct btr_pool *btrp)
 {
        if (!btrp->whead)
@@ -168,25 +172,32 @@ static void btr_pool_deallocate(struct btr_pool *btrp, size_t size)
 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
        list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
 
-struct btr_node *btr_new_node(const char *name, struct btr_node *parent,
-               btr_command_handler handler, void *context)
+/*
+       (parent, child):
+       (NULL, NULL): new, isolated node.
+       (NULL, c): new node becomes root, c must be old root
+       (p, NULL): new leaf node
+       (p, c): new internal node, ch must be child of p
+
+*/
+struct btr_node *btr_new_node(struct btr_node_description *bnd)
 {
        struct btr_node *btrn = para_malloc(sizeof(*btrn));
 
-       btrn->name = para_strdup(name);
-       btrn->parent = parent;
-       btrn->execute = handler;
-       btrn->context = context;
+       btrn->name = para_strdup(bnd->name);
+       btrn->parent = bnd->parent;
+       btrn->execute = bnd->handler;
+       btrn->context = bnd->context;
        btrn->start.tv_sec = 0;
        btrn->start.tv_usec = 0;
-       if (parent)
-               list_add_tail(&btrn->node, &parent->children);
+       if (bnd->parent)
+               list_add_tail(&btrn->node, &bnd->parent->children);
        INIT_LIST_HEAD(&btrn->children);
        INIT_LIST_HEAD(&btrn->input_queue);
-       if (parent)
-               PARA_INFO_LOG("added %s as child of %s\n", name, parent->name);
+       if (bnd->parent)
+               PARA_INFO_LOG("added %s as child of %s\n", bnd->name, bnd->parent->name);
        else
-               PARA_INFO_LOG("added %s as btr root\n", name);
+               PARA_INFO_LOG("added %s as btr root\n", bnd->name);
        return btrn;
 }
 
@@ -484,12 +495,17 @@ void btr_remove_node(struct btr_node *btrn)
 size_t btr_get_input_queue_size(struct btr_node *btrn)
 {
        struct btr_buffer_reference *br;
-       size_t size = 0;
+       size_t size = 0, wrap_consumed = 0;
 
        FOR_EACH_BUFFER_REF(br, btrn) {
-               //PARA_CRIT_LOG("size: %zu\n", size);
+               if (br->wrap_count != 0) {
+                       wrap_consumed = br->consumed;
+                       continue;
+               }
                size += br_available_bytes(br);
        }
+       assert(wrap_consumed <= size);
+       size -= wrap_consumed;
        return size;
 }
 
@@ -778,8 +794,7 @@ int btr_node_status(struct btr_node *btrn, size_t min_iqs,
 {
        size_t iqs;
 
-       if (!btrn)
-               return 0;
+       assert(btrn);
        if (type != BTR_NT_LEAF) {
                if (btr_no_children(btrn))
                        return -E_BTR_NO_CHILD;