+/* returns zero if the push worked, non-zero otherwise */
+static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ struct extent_buffer *right = NULL;
+ struct extent_buffer *mid;
+ struct extent_buffer *left = NULL;
+ struct extent_buffer *parent = NULL;
+ int ret = 0;
+ int wret;
+ int pslot;
+ int orig_slot = path->slots[level];
+ u64 orig_ptr;
+
+ if (level == 0)
+ return 1;
+
+ mid = path->nodes[level];
+ WARN_ON(btrfs_header_generation(mid) != trans->transid);
+ orig_ptr = btrfs_node_blockptr(mid, orig_slot);
+
+ if (level < BTRFS_MAX_LEVEL - 1)
+ parent = path->nodes[level + 1];
+ pslot = path->slots[level + 1];
+
+ if (!parent)
+ return 1;
+
+ left = read_node_slot(root, parent, pslot - 1);
+
+ /* first, try to make some room in the middle buffer */
+ if (left) {
+ u32 left_nr;
+
+ btrfs_tree_lock(left);
+ left_nr = btrfs_header_nritems(left);
+ if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
+ wret = 1;
+ } else {
+ ret = btrfs_cow_block(trans, root, left, parent,
+ pslot - 1, &left);
+ if (ret)
+ wret = 1;
+ else {
+ wret = push_node_left(trans, root,
+ left, mid, 0);
+ }
+ }
+ if (wret < 0)
+ ret = wret;
+ if (wret == 0) {
+ struct btrfs_disk_key disk_key;
+ orig_slot += left_nr;
+ btrfs_node_key(mid, &disk_key, 0);
+ btrfs_set_node_key(parent, &disk_key, pslot);
+ btrfs_mark_buffer_dirty(parent);
+ if (btrfs_header_nritems(left) > orig_slot) {
+ path->nodes[level] = left;
+ path->slots[level + 1] -= 1;
+ path->slots[level] = orig_slot;
+ btrfs_tree_unlock(mid);
+ free_extent_buffer(mid);
+ } else {
+ orig_slot -=
+ btrfs_header_nritems(left);
+ path->slots[level] = orig_slot;
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ }
+ return 0;
+ }
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ }
+ right = read_node_slot(root, parent, pslot + 1);
+
+ /*
+ * then try to empty the right most buffer into the middle
+ */
+ if (right) {
+ u32 right_nr;
+ btrfs_tree_lock(right);
+ right_nr = btrfs_header_nritems(right);
+ if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
+ wret = 1;
+ } else {
+ ret = btrfs_cow_block(trans, root, right,
+ parent, pslot + 1,
+ &right);
+ if (ret)
+ wret = 1;
+ else {
+ wret = balance_node_right(trans, root,
+ right, mid);
+ }
+ }
+ if (wret < 0)
+ ret = wret;
+ if (wret == 0) {
+ struct btrfs_disk_key disk_key;
+
+ btrfs_node_key(right, &disk_key, 0);
+ btrfs_set_node_key(parent, &disk_key, pslot + 1);
+ btrfs_mark_buffer_dirty(parent);
+
+ if (btrfs_header_nritems(mid) <= orig_slot) {
+ path->nodes[level] = right;
+ path->slots[level + 1] += 1;
+ path->slots[level] = orig_slot -
+ btrfs_header_nritems(mid);
+ btrfs_tree_unlock(mid);
+ free_extent_buffer(mid);
+ } else {
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+ return 0;
+ }
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+ return 1;
+}
+
+/*
+ * readahead one full node of leaves
+ */
+static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
+ int level, int slot, u64 objectid)
+{
+ struct extent_buffer *node;
+ struct btrfs_disk_key disk_key;
+ u32 nritems;
+ u64 search;
+ u64 lowest_read;
+ u64 highest_read;
+ u64 nread = 0;
+ int direction = path->reada;
+ struct extent_buffer *eb;
+ u32 nr;
+ u32 blocksize;
+ u32 nscan = 0;
+
+ if (level != 1)
+ return;
+
+ if (!path->nodes[level])
+ return;
+
+ node = path->nodes[level];
+
+ search = btrfs_node_blockptr(node, slot);
+ blocksize = btrfs_level_size(root, level - 1);
+ eb = btrfs_find_tree_block(root, search, blocksize);
+ if (eb) {
+ free_extent_buffer(eb);
+ return;
+ }
+
+ highest_read = search;
+ lowest_read = search;
+
+ nritems = btrfs_header_nritems(node);
+ nr = slot;
+ while(1) {
+ if (direction < 0) {
+ if (nr == 0)
+ break;
+ nr--;
+ } else if (direction > 0) {
+ nr++;
+ if (nr >= nritems)
+ break;
+ }
+ if (path->reada < 0 && objectid) {
+ btrfs_node_key(node, &disk_key, nr);
+ if (btrfs_disk_key_objectid(&disk_key) != objectid)
+ break;
+ }
+ search = btrfs_node_blockptr(node, nr);
+ if ((search >= lowest_read && search <= highest_read) ||
+ (search < lowest_read && lowest_read - search <= 32768) ||
+ (search > highest_read && search - highest_read <= 32768)) {
+ readahead_tree_block(root, search, blocksize,
+ btrfs_node_ptr_generation(node, nr));
+ nread += blocksize;
+ }
+ nscan++;
+ if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
+ break;
+ if(nread > (1024 * 1024) || nscan > 128)
+ break;
+
+ if (search < lowest_read)
+ lowest_read = search;
+ if (search > highest_read)
+ highest_read = search;
+ }
+}
+
+static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
+{
+ int i;
+ int skip_level = level;
+ int no_skips = 0;
+ struct extent_buffer *t;
+
+ for (i = level; i < BTRFS_MAX_LEVEL; i++) {
+ if (!path->nodes[i])
+ break;
+ if (!path->locks[i])
+ break;
+ if (!no_skips && path->slots[i] == 0) {
+ skip_level = i + 1;
+ continue;
+ }
+ if (!no_skips && path->keep_locks) {
+ u32 nritems;
+ t = path->nodes[i];
+ nritems = btrfs_header_nritems(t);
+ if (nritems < 1 || path->slots[i] >= nritems - 1) {
+ skip_level = i + 1;
+ continue;
+ }
+ }
+ if (skip_level < i && i >= lowest_unlock)
+ no_skips = 1;
+
+ t = path->nodes[i];
+ if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
+ btrfs_tree_unlock(t);
+ path->locks[i] = 0;
+ }
+ }
+}
+