Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2822 insertions, 0 deletions

diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c
new file mode 100644
index 0000000000..6c13a8d9a7
--- /dev/null
+++ b/fs/reiserfs/fix_node.c
@@ -0,0 +1,2822 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+
+#include <linux/time.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include "reiserfs.h"
+#include <linux/buffer_head.h>
+
+/*
+ * To make any changes in the tree we find a node that contains item
+ * to be changed/deleted or position in the node we insert a new item
+ * to. We call this node S. To do balancing we need to decide what we
+ * will shift to left/right neighbor, or to a new node, where new item
+ * will be etc. To make this analysis simpler we build virtual
+ * node. Virtual node is an array of items, that will replace items of
+ * node S. (For instance if we are going to delete an item, virtual
+ * node does not contain it). Virtual node keeps information about
+ * item sizes and types, mergeability of first and last items, sizes
+ * of all entries in directory item. We use this array of items when
+ * calculating what we can shift to neighbors and how many nodes we
+ * have to have if we do not any shiftings, if we shift to left/right
+ * neighbor or to both.
+ */
+
+/*
+ * Takes item number in virtual node, returns number of item
+ * that it has in source buffer
+ */
+static inline int old_item_num(int new_num, int affected_item_num, int mode)
+{
+	if (mode == M_PASTE || mode == M_CUT || new_num < affected_item_num)
+		return new_num;
+
+	if (mode == M_INSERT) {
+
+		RFALSE(new_num == 0,
+		       "vs-8005: for INSERT mode and item number of inserted item");
+
+		return new_num - 1;
+	}
+
+	RFALSE(mode != M_DELETE,
+	       "vs-8010: old_item_num: mode must be M_DELETE (mode = \'%c\'",
+	       mode);
+	/* delete mode */
+	return new_num + 1;
+}
+
+static void create_virtual_node(struct tree_balance *tb, int h)
+{
+	struct item_head *ih;
+	struct virtual_node *vn = tb->tb_vn;
+	int new_num;
+	struct buffer_head *Sh;	/* this comes from tb->S[h] */
+
+	Sh = PATH_H_PBUFFER(tb->tb_path, h);
+
+	/* size of changed node */
+	vn->vn_size =
+	    MAX_CHILD_SIZE(Sh) - B_FREE_SPACE(Sh) + tb->insert_size[h];
+
+	/* for internal nodes array if virtual items is not created */
+	if (h) {
+		vn->vn_nr_item = (vn->vn_size - DC_SIZE) / (DC_SIZE + KEY_SIZE);
+		return;
+	}
+
+	/* number of items in virtual node  */
+	vn->vn_nr_item =
+	    B_NR_ITEMS(Sh) + ((vn->vn_mode == M_INSERT) ? 1 : 0) -
+	    ((vn->vn_mode == M_DELETE) ? 1 : 0);
+
+	/* first virtual item */
+	vn->vn_vi = (struct virtual_item *)(tb->tb_vn + 1);
+	memset(vn->vn_vi, 0, vn->vn_nr_item * sizeof(struct virtual_item));
+	vn->vn_free_ptr += vn->vn_nr_item * sizeof(struct virtual_item);
+
+	/* first item in the node */
+	ih = item_head(Sh, 0);
+
+	/* define the mergeability for 0-th item (if it is not being deleted) */
+	if (op_is_left_mergeable(&ih->ih_key, Sh->b_size)
+	    && (vn->vn_mode != M_DELETE || vn->vn_affected_item_num))
+		vn->vn_vi[0].vi_type |= VI_TYPE_LEFT_MERGEABLE;
+
+	/*
+	 * go through all items that remain in the virtual
+	 * node (except for the new (inserted) one)
+	 */
+	for (new_num = 0; new_num < vn->vn_nr_item; new_num++) {
+		int j;
+		struct virtual_item *vi = vn->vn_vi + new_num;
+		int is_affected =
+		    ((new_num != vn->vn_affected_item_num) ? 0 : 1);
+
+		if (is_affected && vn->vn_mode == M_INSERT)
+			continue;
+
+		/* get item number in source node */
+		j = old_item_num(new_num, vn->vn_affected_item_num,
+				 vn->vn_mode);
+
+		vi->vi_item_len += ih_item_len(ih + j) + IH_SIZE;
+		vi->vi_ih = ih + j;
+		vi->vi_item = ih_item_body(Sh, ih + j);
+		vi->vi_uarea = vn->vn_free_ptr;
+
+		/*
+		 * FIXME: there is no check that item operation did not
+		 * consume too much memory
+		 */
+		vn->vn_free_ptr +=
+		    op_create_vi(vn, vi, is_affected, tb->insert_size[0]);
+		if (tb->vn_buf + tb->vn_buf_size < vn->vn_free_ptr)
+			reiserfs_panic(tb->tb_sb, "vs-8030",
+				       "virtual node space consumed");
+
+		if (!is_affected)
+			/* this is not being changed */
+			continue;
+
+		if (vn->vn_mode == M_PASTE || vn->vn_mode == M_CUT) {
+			vn->vn_vi[new_num].vi_item_len += tb->insert_size[0];
+			/* pointer to data which is going to be pasted */
+			vi->vi_new_data = vn->vn_data;
+		}
+	}
+
+	/* virtual inserted item is not defined yet */
+	if (vn->vn_mode == M_INSERT) {
+		struct virtual_item *vi = vn->vn_vi + vn->vn_affected_item_num;
+
+		RFALSE(vn->vn_ins_ih == NULL,
+		       "vs-8040: item header of inserted item is not specified");
+		vi->vi_item_len = tb->insert_size[0];
+		vi->vi_ih = vn->vn_ins_ih;
+		vi->vi_item = vn->vn_data;
+		vi->vi_uarea = vn->vn_free_ptr;
+
+		op_create_vi(vn, vi, 0 /*not pasted or cut */ ,
+			     tb->insert_size[0]);
+	}
+
+	/*
+	 * set right merge flag we take right delimiting key and
+	 * check whether it is a mergeable item
+	 */
+	if (tb->CFR[0]) {
+		struct reiserfs_key *key;
+
+		key = internal_key(tb->CFR[0], tb->rkey[0]);
+		if (op_is_left_mergeable(key, Sh->b_size)
+		    && (vn->vn_mode != M_DELETE
+			|| vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1))
+			vn->vn_vi[vn->vn_nr_item - 1].vi_type |=
+			    VI_TYPE_RIGHT_MERGEABLE;
+
+#ifdef CONFIG_REISERFS_CHECK
+		if (op_is_left_mergeable(key, Sh->b_size) &&
+		    !(vn->vn_mode != M_DELETE
+		      || vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1)) {
+			/*
+			 * we delete last item and it could be merged
+			 * with right neighbor's first item
+			 */
+			if (!
+			    (B_NR_ITEMS(Sh) == 1
+			     && is_direntry_le_ih(item_head(Sh, 0))
+			     && ih_entry_count(item_head(Sh, 0)) == 1)) {
+				/*
+				 * node contains more than 1 item, or item
+				 * is not directory item, or this item
+				 * contains more than 1 entry
+				 */
+				print_block(Sh, 0, -1, -1);
+				reiserfs_panic(tb->tb_sb, "vs-8045",
+					       "rdkey %k, affected item==%d "
+					       "(mode==%c) Must be %c",
+					       key, vn->vn_affected_item_num,
+					       vn->vn_mode, M_DELETE);
+			}
+		}
+#endif
+
+	}
+}
+
+/*
+ * Using virtual node check, how many items can be
+ * shifted to left neighbor
+ */
+static void check_left(struct tree_balance *tb, int h, int cur_free)
+{
+	int i;
+	struct virtual_node *vn = tb->tb_vn;
+	struct virtual_item *vi;
+	int d_size, ih_size;
+
+	RFALSE(cur_free < 0, "vs-8050: cur_free (%d) < 0", cur_free);
+
+	/* internal level */
+	if (h > 0) {
+		tb->lnum[h] = cur_free / (DC_SIZE + KEY_SIZE);
+		return;
+	}
+
+	/* leaf level */
+
+	if (!cur_free || !vn->vn_nr_item) {
+		/* no free space or nothing to move */
+		tb->lnum[h] = 0;
+		tb->lbytes = -1;
+		return;
+	}
+
+	RFALSE(!PATH_H_PPARENT(tb->tb_path, 0),
+	       "vs-8055: parent does not exist or invalid");
+
+	vi = vn->vn_vi;
+	if ((unsigned int)cur_free >=
+	    (vn->vn_size -
+	     ((vi->vi_type & VI_TYPE_LEFT_MERGEABLE) ? IH_SIZE : 0))) {
+		/* all contents of S[0] fits into L[0] */
+
+		RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE,
+		       "vs-8055: invalid mode or balance condition failed");
+
+		tb->lnum[0] = vn->vn_nr_item;
+		tb->lbytes = -1;
+		return;
+	}
+
+	d_size = 0, ih_size = IH_SIZE;
+
+	/* first item may be merge with last item in left neighbor */
+	if (vi->vi_type & VI_TYPE_LEFT_MERGEABLE)
+		d_size = -((int)IH_SIZE), ih_size = 0;
+
+	tb->lnum[0] = 0;
+	for (i = 0; i < vn->vn_nr_item;
+	     i++, ih_size = IH_SIZE, d_size = 0, vi++) {
+		d_size += vi->vi_item_len;
+		if (cur_free >= d_size) {
+			/* the item can be shifted entirely */
+			cur_free -= d_size;
+			tb->lnum[0]++;
+			continue;
+		}
+
+		/* the item cannot be shifted entirely, try to split it */
+		/*
+		 * check whether L[0] can hold ih and at least one byte
+		 * of the item body
+		 */
+
+		/* cannot shift even a part of the current item */
+		if (cur_free <= ih_size) {
+			tb->lbytes = -1;
+			return;
+		}
+		cur_free -= ih_size;
+
+		tb->lbytes = op_check_left(vi, cur_free, 0, 0);
+		if (tb->lbytes != -1)
+			/* count partially shifted item */
+			tb->lnum[0]++;
+
+		break;
+	}
+
+	return;
+}
+
+/*
+ * Using virtual node check, how many items can be
+ * shifted to right neighbor
+ */
+static void check_right(struct tree_balance *tb, int h, int cur_free)
+{
+	int i;
+	struct virtual_node *vn = tb->tb_vn;
+	struct virtual_item *vi;
+	int d_size, ih_size;
+
+	RFALSE(cur_free < 0, "vs-8070: cur_free < 0");
+
+	/* internal level */
+	if (h > 0) {
+		tb->rnum[h] = cur_free / (DC_SIZE + KEY_SIZE);
+		return;
+	}
+
+	/* leaf level */
+
+	if (!cur_free || !vn->vn_nr_item) {
+		/* no free space  */
+		tb->rnum[h] = 0;
+		tb->rbytes = -1;
+		return;
+	}
+
+	RFALSE(!PATH_H_PPARENT(tb->tb_path, 0),
+	       "vs-8075: parent does not exist or invalid");
+
+	vi = vn->vn_vi + vn->vn_nr_item - 1;
+	if ((unsigned int)cur_free >=
+	    (vn->vn_size -
+	     ((vi->vi_type & VI_TYPE_RIGHT_MERGEABLE) ? IH_SIZE : 0))) {
+		/* all contents of S[0] fits into R[0] */
+
+		RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE,
+		       "vs-8080: invalid mode or balance condition failed");
+
+		tb->rnum[h] = vn->vn_nr_item;
+		tb->rbytes = -1;
+		return;
+	}
+
+	d_size = 0, ih_size = IH_SIZE;
+
+	/* last item may be merge with first item in right neighbor */
+	if (vi->vi_type & VI_TYPE_RIGHT_MERGEABLE)
+		d_size = -(int)IH_SIZE, ih_size = 0;
+
+	tb->rnum[0] = 0;
+	for (i = vn->vn_nr_item - 1; i >= 0;
+	     i--, d_size = 0, ih_size = IH_SIZE, vi--) {
+		d_size += vi->vi_item_len;
+		if (cur_free >= d_size) {
+			/* the item can be shifted entirely */
+			cur_free -= d_size;
+			tb->rnum[0]++;
+			continue;
+		}
+
+		/*
+		 * check whether R[0] can hold ih and at least one
+		 * byte of the item body
+		 */
+
+		/* cannot shift even a part of the current item */
+		if (cur_free <= ih_size) {
+			tb->rbytes = -1;
+			return;
+		}
+
+		/*
+		 * R[0] can hold the header of the item and at least
+		 * one byte of its body
+		 */
+		cur_free -= ih_size;	/* cur_free is still > 0 */
+
+		tb->rbytes = op_check_right(vi, cur_free);
+		if (tb->rbytes != -1)
+			/* count partially shifted item */
+			tb->rnum[0]++;
+
+		break;
+	}
+
+	return;
+}
+
+/*
+ * from - number of items, which are shifted to left neighbor entirely
+ * to - number of item, which are shifted to right neighbor entirely
+ * from_bytes - number of bytes of boundary item (or directory entries)
+ *              which are shifted to left neighbor
+ * to_bytes - number of bytes of boundary item (or directory entries)
+ *            which are shifted to right neighbor
+ */
+static int get_num_ver(int mode, struct tree_balance *tb, int h,
+		       int from, int from_bytes,
+		       int to, int to_bytes, short *snum012, int flow)
+{
+	int i;
+	int units;
+	struct virtual_node *vn = tb->tb_vn;
+	int total_node_size, max_node_size, current_item_size;
+	int needed_nodes;
+
+	/* position of item we start filling node from */
+	int start_item;
+
+	/* position of item we finish filling node by */
+	int end_item;
+
+	/*
+	 * number of first bytes (entries for directory) of start_item-th item
+	 * we do not include into node that is being filled
+	 */
+	int start_bytes;
+
+	/*
+	 * number of last bytes (entries for directory) of end_item-th item
+	 * we do node include into node that is being filled
+	 */
+	int end_bytes;
+
+	/*
+	 * these are positions in virtual item of items, that are split
+	 * between S[0] and S1new and S1new and S2new
+	 */
+	int split_item_positions[2];
+
+	split_item_positions[0] = -1;
+	split_item_positions[1] = -1;
+
+	/*
+	 * We only create additional nodes if we are in insert or paste mode
+	 * or we are in replace mode at the internal level. If h is 0 and
+	 * the mode is M_REPLACE then in fix_nodes we change the mode to
+	 * paste or insert before we get here in the code.
+	 */
+	RFALSE(tb->insert_size[h] < 0 || (mode != M_INSERT && mode != M_PASTE),
+	       "vs-8100: insert_size < 0 in overflow");
+
+	max_node_size = MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, h));
+
+	/*
+	 * snum012 [0-2] - number of items, that lay
+	 * to S[0], first new node and second new node
+	 */
+	snum012[3] = -1;	/* s1bytes */
+	snum012[4] = -1;	/* s2bytes */
+
+	/* internal level */
+	if (h > 0) {
+		i = ((to - from) * (KEY_SIZE + DC_SIZE) + DC_SIZE);
+		if (i == max_node_size)
+			return 1;
+		return (i / max_node_size + 1);
+	}
+
+	/* leaf level */
+	needed_nodes = 1;
+	total_node_size = 0;
+
+	/* start from 'from'-th item */
+	start_item = from;
+	/* skip its first 'start_bytes' units */
+	start_bytes = ((from_bytes != -1) ? from_bytes : 0);
+
+	/* last included item is the 'end_item'-th one */
+	end_item = vn->vn_nr_item - to - 1;
+	/* do not count last 'end_bytes' units of 'end_item'-th item */
+	end_bytes = (to_bytes != -1) ? to_bytes : 0;
+
+	/*
+	 * go through all item beginning from the start_item-th item
+	 * and ending by the end_item-th item. Do not count first
+	 * 'start_bytes' units of 'start_item'-th item and last
+	 * 'end_bytes' of 'end_item'-th item
+	 */
+	for (i = start_item; i <= end_item; i++) {
+		struct virtual_item *vi = vn->vn_vi + i;
+		int skip_from_end = ((i == end_item) ? end_bytes : 0);
+
+		RFALSE(needed_nodes > 3, "vs-8105: too many nodes are needed");
+
+		/* get size of current item */
+		current_item_size = vi->vi_item_len;
+
+		/*
+		 * do not take in calculation head part (from_bytes)
+		 * of from-th item
+		 */
+		current_item_size -=
+		    op_part_size(vi, 0 /*from start */ , start_bytes);
+
+		/* do not take in calculation tail part of last item */
+		current_item_size -=
+		    op_part_size(vi, 1 /*from end */ , skip_from_end);
+
+		/* if item fits into current node entierly */
+		if (total_node_size + current_item_size <= max_node_size) {
+			snum012[needed_nodes - 1]++;
+			total_node_size += current_item_size;
+			start_bytes = 0;
+			continue;
+		}
+
+		/*
+		 * virtual item length is longer, than max size of item in
+		 * a node. It is impossible for direct item
+		 */
+		if (current_item_size > max_node_size) {
+			RFALSE(is_direct_le_ih(vi->vi_ih),
+			       "vs-8110: "
+			       "direct item length is %d. It can not be longer than %d",
+			       current_item_size, max_node_size);
+			/* we will try to split it */
+			flow = 1;
+		}
+
+		/* as we do not split items, take new node and continue */
+		if (!flow) {
+			needed_nodes++;
+			i--;
+			total_node_size = 0;
+			continue;
+		}
+
+		/*
+		 * calculate number of item units which fit into node being
+		 * filled
+		 */
+		{
+			int free_space;
+
+			free_space = max_node_size - total_node_size - IH_SIZE;
+			units =
+			    op_check_left(vi, free_space, start_bytes,
+					  skip_from_end);
+			/*
+			 * nothing fits into current node, take new
+			 * node and continue
+			 */
+			if (units == -1) {
+				needed_nodes++, i--, total_node_size = 0;
+				continue;
+			}
+		}
+
+		/* something fits into the current node */
+		start_bytes += units;
+		snum012[needed_nodes - 1 + 3] = units;
+
+		if (needed_nodes > 2)
+			reiserfs_warning(tb->tb_sb, "vs-8111",
+					 "split_item_position is out of range");
+		snum012[needed_nodes - 1]++;
+		split_item_positions[needed_nodes - 1] = i;
+		needed_nodes++;
+		/* continue from the same item with start_bytes != -1 */
+		start_item = i;
+		i--;
+		total_node_size = 0;
+	}
+
+	/*
+	 * sum012[4] (if it is not -1) contains number of units of which
+	 * are to be in S1new, snum012[3] - to be in S0. They are supposed
+	 * to be S1bytes and S2bytes correspondingly, so recalculate
+	 */
+	if (snum012[4] > 0) {
+		int split_item_num;
+		int bytes_to_r, bytes_to_l;
+		int bytes_to_S1new;
+
+		split_item_num = split_item_positions[1];
+		bytes_to_l =
+		    ((from == split_item_num
+		      && from_bytes != -1) ? from_bytes : 0);
+		bytes_to_r =
+		    ((end_item == split_item_num
+		      && end_bytes != -1) ? end_bytes : 0);
+		bytes_to_S1new =
+		    ((split_item_positions[0] ==
+		      split_item_positions[1]) ? snum012[3] : 0);
+
+		/* s2bytes */
+		snum012[4] =
+		    op_unit_num(&vn->vn_vi[split_item_num]) - snum012[4] -
+		    bytes_to_r - bytes_to_l - bytes_to_S1new;
+
+		if (vn->vn_vi[split_item_num].vi_index != TYPE_DIRENTRY &&
+		    vn->vn_vi[split_item_num].vi_index != TYPE_INDIRECT)
+			reiserfs_warning(tb->tb_sb, "vs-8115",
+					 "not directory or indirect item");
+	}
+
+	/* now we know S2bytes, calculate S1bytes */
+	if (snum012[3] > 0) {
+		int split_item_num;
+		int bytes_to_r, bytes_to_l;
+		int bytes_to_S2new;
+
+		split_item_num = split_item_positions[0];
+		bytes_to_l =
+		    ((from == split_item_num
+		      && from_bytes != -1) ? from_bytes : 0);
+		bytes_to_r =
+		    ((end_item == split_item_num
+		      && end_bytes != -1) ? end_bytes : 0);
+		bytes_to_S2new =
+		    ((split_item_positions[0] == split_item_positions[1]
+		      && snum012[4] != -1) ? snum012[4] : 0);
+
+		/* s1bytes */
+		snum012[3] =
+		    op_unit_num(&vn->vn_vi[split_item_num]) - snum012[3] -
+		    bytes_to_r - bytes_to_l - bytes_to_S2new;
+	}
+
+	return needed_nodes;
+}
+
+
+/*
+ * Set parameters for balancing.
+ * Performs write of results of analysis of balancing into structure tb,
+ * where it will later be used by the functions that actually do the balancing.
+ * Parameters:
+ *	tb	tree_balance structure;
+ *	h	current level of the node;
+ *	lnum	number of items from S[h] that must be shifted to L[h];
+ *	rnum	number of items from S[h] that must be shifted to R[h];
+ *	blk_num	number of blocks that S[h] will be splitted into;
+ *	s012	number of items that fall into splitted nodes.
+ *	lbytes	number of bytes which flow to the left neighbor from the
+ *              item that is not shifted entirely
+ *	rbytes	number of bytes which flow to the right neighbor from the
+ *              item that is not shifted entirely
+ *	s1bytes	number of bytes which flow to the first  new node when
+ *              S[0] splits (this number is contained in s012 array)
+ */
+
+static void set_parameters(struct tree_balance *tb, int h, int lnum,
+			   int rnum, int blk_num, short *s012, int lb, int rb)
+{
+
+	tb->lnum[h] = lnum;
+	tb->rnum[h] = rnum;
+	tb->blknum[h] = blk_num;
+
+	/* only for leaf level */
+	if (h == 0) {
+		if (s012 != NULL) {
+			tb->s0num = *s012++;
+			tb->snum[0] = *s012++;
+			tb->snum[1] = *s012++;
+			tb->sbytes[0] = *s012++;
+			tb->sbytes[1] = *s012;
+		}
+		tb->lbytes = lb;
+		tb->rbytes = rb;
+	}
+	PROC_INFO_ADD(tb->tb_sb, lnum[h], lnum);
+	PROC_INFO_ADD(tb->tb_sb, rnum[h], rnum);
+
+	PROC_INFO_ADD(tb->tb_sb, lbytes[h], lb);
+	PROC_INFO_ADD(tb->tb_sb, rbytes[h], rb);
+}
+
+/*
+ * check if node disappears if we shift tb->lnum[0] items to left
+ * neighbor and tb->rnum[0] to the right one.
+ */
+static int is_leaf_removable(struct tree_balance *tb)
+{
+	struct virtual_node *vn = tb->tb_vn;
+	int to_left, to_right;
+	int size;
+	int remain_items;
+
+	/*
+	 * number of items that will be shifted to left (right) neighbor
+	 * entirely
+	 */
+	to_left = tb->lnum[0] - ((tb->lbytes != -1) ? 1 : 0);
+	to_right = tb->rnum[0] - ((tb->rbytes != -1) ? 1 : 0);
+	remain_items = vn->vn_nr_item;
+
+	/* how many items remain in S[0] after shiftings to neighbors */
+	remain_items -= (to_left + to_right);
+
+	/* all content of node can be shifted to neighbors */
+	if (remain_items < 1) {
+		set_parameters(tb, 0, to_left, vn->vn_nr_item - to_left, 0,
+			       NULL, -1, -1);
+		return 1;
+	}
+
+	/* S[0] is not removable */
+	if (remain_items > 1 || tb->lbytes == -1 || tb->rbytes == -1)
+		return 0;
+
+	/* check whether we can divide 1 remaining item between neighbors */
+
+	/* get size of remaining item (in item units) */
+	size = op_unit_num(&vn->vn_vi[to_left]);
+
+	if (tb->lbytes + tb->rbytes >= size) {
+		set_parameters(tb, 0, to_left + 1, to_right + 1, 0, NULL,
+			       tb->lbytes, -1);
+		return 1;
+	}
+
+	return 0;
+}
+
+/* check whether L, S, R can be joined in one node */
+static int are_leaves_removable(struct tree_balance *tb, int lfree, int rfree)
+{
+	struct virtual_node *vn = tb->tb_vn;
+	int ih_size;
+	struct buffer_head *S0;
+
+	S0 = PATH_H_PBUFFER(tb->tb_path, 0);
+
+	ih_size = 0;
+	if (vn->vn_nr_item) {
+		if (vn->vn_vi[0].vi_type & VI_TYPE_LEFT_MERGEABLE)
+			ih_size += IH_SIZE;
+
+		if (vn->vn_vi[vn->vn_nr_item - 1].
+		    vi_type & VI_TYPE_RIGHT_MERGEABLE)
+			ih_size += IH_SIZE;
+	} else {
+		/* there was only one item and it will be deleted */
+		struct item_head *ih;
+
+		RFALSE(B_NR_ITEMS(S0) != 1,
+		       "vs-8125: item number must be 1: it is %d",
+		       B_NR_ITEMS(S0));
+
+		ih = item_head(S0, 0);
+		if (tb->CFR[0]
+		    && !comp_short_le_keys(&ih->ih_key,
+					   internal_key(tb->CFR[0],
+							  tb->rkey[0])))
+			/*
+			 * Directory must be in correct state here: that is
+			 * somewhere at the left side should exist first
+			 * directory item. But the item being deleted can
+			 * not be that first one because its right neighbor
+			 * is item of the same directory. (But first item
+			 * always gets deleted in last turn). So, neighbors
+			 * of deleted item can be merged, so we can save
+			 * ih_size
+			 */
+			if (is_direntry_le_ih(ih)) {
+				ih_size = IH_SIZE;
+
+				/*
+				 * we might check that left neighbor exists
+				 * and is of the same directory
+				 */
+				RFALSE(le_ih_k_offset(ih) == DOT_OFFSET,
+				       "vs-8130: first directory item can not be removed until directory is not empty");
+			}
+
+	}
+
+	if (MAX_CHILD_SIZE(S0) + vn->vn_size <= rfree + lfree + ih_size) {
+		set_parameters(tb, 0, -1, -1, -1, NULL, -1, -1);
+		PROC_INFO_INC(tb->tb_sb, leaves_removable);
+		return 1;
+	}
+	return 0;
+
+}
+
+/* when we do not split item, lnum and rnum are numbers of entire items */
+#define SET_PAR_SHIFT_LEFT \
+if (h)\
+{\
+   int to_l;\
+   \
+   to_l = (MAX_NR_KEY(Sh)+1 - lpar + vn->vn_nr_item + 1) / 2 -\
+	      (MAX_NR_KEY(Sh) + 1 - lpar);\
+	      \
+	      set_parameters (tb, h, to_l, 0, lnver, NULL, -1, -1);\
+}\
+else \
+{\
+   if (lset==LEFT_SHIFT_FLOW)\
+     set_parameters (tb, h, lpar, 0, lnver, snum012+lset,\
+		     tb->lbytes, -1);\
+   else\
+     set_parameters (tb, h, lpar - (tb->lbytes!=-1), 0, lnver, snum012+lset,\
+		     -1, -1);\
+}
+
+#define SET_PAR_SHIFT_RIGHT \
+if (h)\
+{\
+   int to_r;\
+   \
+   to_r = (MAX_NR_KEY(Sh)+1 - rpar + vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - rpar);\
+   \
+   set_parameters (tb, h, 0, to_r, rnver, NULL, -1, -1);\
+}\
+else \
+{\
+   if (rset==RIGHT_SHIFT_FLOW)\
+     set_parameters (tb, h, 0, rpar, rnver, snum012+rset,\
+		  -1, tb->rbytes);\
+   else\
+     set_parameters (tb, h, 0, rpar - (tb->rbytes!=-1), rnver, snum012+rset,\
+		  -1, -1);\
+}
+
+static void free_buffers_in_tb(struct tree_balance *tb)
+{
+	int i;
+
+	pathrelse(tb->tb_path);
+
+	for (i = 0; i < MAX_HEIGHT; i++) {
+		brelse(tb->L[i]);
+		brelse(tb->R[i]);
+		brelse(tb->FL[i]);
+		brelse(tb->FR[i]);
+		brelse(tb->CFL[i]);
+		brelse(tb->CFR[i]);
+
+		tb->L[i] = NULL;
+		tb->R[i] = NULL;
+		tb->FL[i] = NULL;
+		tb->FR[i] = NULL;
+		tb->CFL[i] = NULL;
+		tb->CFR[i] = NULL;
+	}
+}
+
+/*
+ * Get new buffers for storing new nodes that are created while balancing.
+ * Returns:	SCHEDULE_OCCURRED - schedule occurred while the function worked;
+ *	        CARRY_ON - schedule didn't occur while the function worked;
+ *	        NO_DISK_SPACE - no disk space.
+ */
+/* The function is NOT SCHEDULE-SAFE! */
+static int get_empty_nodes(struct tree_balance *tb, int h)
+{
+	struct buffer_head *new_bh, *Sh = PATH_H_PBUFFER(tb->tb_path, h);
+	b_blocknr_t *blocknr, blocknrs[MAX_AMOUNT_NEEDED] = { 0, };
+	int counter, number_of_freeblk;
+	int  amount_needed;	/* number of needed empty blocks */
+	int  retval = CARRY_ON;
+	struct super_block *sb = tb->tb_sb;
+
+	/*
+	 * number_of_freeblk is the number of empty blocks which have been
+	 * acquired for use by the balancing algorithm minus the number of
+	 * empty blocks used in the previous levels of the analysis,
+	 * number_of_freeblk = tb->cur_blknum can be non-zero if a schedule
+	 * occurs after empty blocks are acquired, and the balancing analysis
+	 * is then restarted, amount_needed is the number needed by this
+	 * level (h) of the balancing analysis.
+	 *
+	 * Note that for systems with many processes writing, it would be
+	 * more layout optimal to calculate the total number needed by all
+	 * levels and then to run reiserfs_new_blocks to get all of them at
+	 * once.
+	 */
+
+	/*
+	 * Initiate number_of_freeblk to the amount acquired prior to the
+	 * restart of the analysis or 0 if not restarted, then subtract the
+	 * amount needed by all of the levels of the tree below h.
+	 */
+	/* blknum includes S[h], so we subtract 1 in this calculation */
+	for (counter = 0, number_of_freeblk = tb->cur_blknum;
+	     counter < h; counter++)
+		number_of_freeblk -=
+		    (tb->blknum[counter]) ? (tb->blknum[counter] -
+						   1) : 0;
+
+	/* Allocate missing empty blocks. */
+	/* if Sh == 0  then we are getting a new root */
+	amount_needed = (Sh) ? (tb->blknum[h] - 1) : 1;
+	/*
+	 * Amount_needed = the amount that we need more than the
+	 * amount that we have.
+	 */
+	if (amount_needed > number_of_freeblk)
+		amount_needed -= number_of_freeblk;
+	else	/* If we have enough already then there is nothing to do. */
+		return CARRY_ON;
+
+	/*
+	 * No need to check quota - is not allocated for blocks used
+	 * for formatted nodes
+	 */
+	if (reiserfs_new_form_blocknrs(tb, blocknrs,
+				       amount_needed) == NO_DISK_SPACE)
+		return NO_DISK_SPACE;
+
+	/* for each blocknumber we just got, get a buffer and stick it on FEB */
+	for (blocknr = blocknrs, counter = 0;
+	     counter < amount_needed; blocknr++, counter++) {
+
+		RFALSE(!*blocknr,
+		       "PAP-8135: reiserfs_new_blocknrs failed when got new blocks");
+
+		new_bh = sb_getblk(sb, *blocknr);
+		RFALSE(buffer_dirty(new_bh) ||
+		       buffer_journaled(new_bh) ||
+		       buffer_journal_dirty(new_bh),
+		       "PAP-8140: journaled or dirty buffer %b for the new block",
+		       new_bh);
+
+		/* Put empty buffers into the array. */
+		RFALSE(tb->FEB[tb->cur_blknum],
+		       "PAP-8141: busy slot for new buffer");
+
+		set_buffer_journal_new(new_bh);
+		tb->FEB[tb->cur_blknum++] = new_bh;
+	}
+
+	if (retval == CARRY_ON && FILESYSTEM_CHANGED_TB(tb))
+		retval = REPEAT_SEARCH;
+
+	return retval;
+}
+
+/*
+ * Get free space of the left neighbor, which is stored in the parent
+ * node of the left neighbor.
+ */
+static int get_lfree(struct tree_balance *tb, int h)
+{
+	struct buffer_head *l, *f;
+	int order;
+
+	if ((f = PATH_H_PPARENT(tb->tb_path, h)) == NULL ||
+	    (l = tb->FL[h]) == NULL)
+		return 0;
+
+	if (f == l)
+		order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) - 1;
+	else {
+		order = B_NR_ITEMS(l);
+		f = l;
+	}
+
+	return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order)));
+}
+
+/*
+ * Get free space of the right neighbor,
+ * which is stored in the parent node of the right neighbor.
+ */
+static int get_rfree(struct tree_balance *tb, int h)
+{
+	struct buffer_head *r, *f;
+	int order;
+
+	if ((f = PATH_H_PPARENT(tb->tb_path, h)) == NULL ||
+	    (r = tb->FR[h]) == NULL)
+		return 0;
+
+	if (f == r)
+		order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) + 1;
+	else {
+		order = 0;
+		f = r;
+	}
+
+	return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order)));
+
+}
+
+/* Check whether left neighbor is in memory. */
+static int is_left_neighbor_in_cache(struct tree_balance *tb, int h)
+{
+	struct buffer_head *father, *left;
+	struct super_block *sb = tb->tb_sb;
+	b_blocknr_t left_neighbor_blocknr;
+	int left_neighbor_position;
+
+	/* Father of the left neighbor does not exist. */
+	if (!tb->FL[h])
+		return 0;
+
+	/* Calculate father of the node to be balanced. */
+	father = PATH_H_PBUFFER(tb->tb_path, h + 1);
+
+	RFALSE(!father ||
+	       !B_IS_IN_TREE(father) ||
+	       !B_IS_IN_TREE(tb->FL[h]) ||
+	       !buffer_uptodate(father) ||
+	       !buffer_uptodate(tb->FL[h]),
+	       "vs-8165: F[h] (%b) or FL[h] (%b) is invalid",
+	       father, tb->FL[h]);
+
+	/*
+	 * Get position of the pointer to the left neighbor
+	 * into the left father.
+	 */
+	left_neighbor_position = (father == tb->FL[h]) ?
+	    tb->lkey[h] : B_NR_ITEMS(tb->FL[h]);
+	/* Get left neighbor block number. */
+	left_neighbor_blocknr =
+	    B_N_CHILD_NUM(tb->FL[h], left_neighbor_position);
+	/* Look for the left neighbor in the cache. */
+	if ((left = sb_find_get_block(sb, left_neighbor_blocknr))) {
+
+		RFALSE(buffer_uptodate(left) && !B_IS_IN_TREE(left),
+		       "vs-8170: left neighbor (%b %z) is not in the tree",
+		       left, left);
+		put_bh(left);
+		return 1;
+	}
+
+	return 0;
+}
+
+#define LEFT_PARENTS  'l'
+#define RIGHT_PARENTS 'r'
+
+static void decrement_key(struct cpu_key *key)
+{
+	/* call item specific function for this key */
+	item_ops[cpu_key_k_type(key)]->decrement_key(key);
+}
+
+/*
+ * Calculate far left/right parent of the left/right neighbor of the
+ * current node, that is calculate the left/right (FL[h]/FR[h]) neighbor
+ * of the parent F[h].
+ * Calculate left/right common parent of the current node and L[h]/R[h].
+ * Calculate left/right delimiting key position.
+ * Returns:	PATH_INCORRECT    - path in the tree is not correct
+ *		SCHEDULE_OCCURRED - schedule occurred while the function worked
+ *	        CARRY_ON          - schedule didn't occur while the function
+ *				    worked
+ */
+static int get_far_parent(struct tree_balance *tb,
+			  int h,
+			  struct buffer_head **pfather,
+			  struct buffer_head **pcom_father, char c_lr_par)
+{
+	struct buffer_head *parent;
+	INITIALIZE_PATH(s_path_to_neighbor_father);
+	struct treepath *path = tb->tb_path;
+	struct cpu_key s_lr_father_key;
+	int counter,
+	    position = INT_MAX,
+	    first_last_position = 0,
+	    path_offset = PATH_H_PATH_OFFSET(path, h);
+
+	/*
+	 * Starting from F[h] go upwards in the tree, and look for the common
+	 * ancestor of F[h], and its neighbor l/r, that should be obtained.
+	 */
+
+	counter = path_offset;
+
+	RFALSE(counter < FIRST_PATH_ELEMENT_OFFSET,
+	       "PAP-8180: invalid path length");
+
+	for (; counter > FIRST_PATH_ELEMENT_OFFSET; counter--) {
+		/*
+		 * Check whether parent of the current buffer in the path
+		 * is really parent in the tree.
+		 */
+		if (!B_IS_IN_TREE
+		    (parent = PATH_OFFSET_PBUFFER(path, counter - 1)))
+			return REPEAT_SEARCH;
+
+		/* Check whether position in the parent is correct. */
+		if ((position =
+		     PATH_OFFSET_POSITION(path,
+					  counter - 1)) >
+		    B_NR_ITEMS(parent))
+			return REPEAT_SEARCH;
+
+		/*
+		 * Check whether parent at the path really points
+		 * to the child.
+		 */
+		if (B_N_CHILD_NUM(parent, position) !=
+		    PATH_OFFSET_PBUFFER(path, counter)->b_blocknr)
+			return REPEAT_SEARCH;
+
+		/*
+		 * Return delimiting key if position in the parent is not
+		 * equal to first/last one.
+		 */
+		if (c_lr_par == RIGHT_PARENTS)
+			first_last_position = B_NR_ITEMS(parent);
+		if (position != first_last_position) {
+			*pcom_father = parent;
+			get_bh(*pcom_father);
+			/*(*pcom_father = parent)->b_count++; */
+			break;
+		}
+	}
+
+	/* if we are in the root of the tree, then there is no common father */
+	if (counter == FIRST_PATH_ELEMENT_OFFSET) {
+		/*
+		 * Check whether first buffer in the path is the
+		 * root of the tree.
+		 */
+		if (PATH_OFFSET_PBUFFER
+		    (tb->tb_path,
+		     FIRST_PATH_ELEMENT_OFFSET)->b_blocknr ==
+		    SB_ROOT_BLOCK(tb->tb_sb)) {
+			*pfather = *pcom_father = NULL;
+			return CARRY_ON;
+		}
+		return REPEAT_SEARCH;
+	}
+
+	RFALSE(B_LEVEL(*pcom_father) <= DISK_LEAF_NODE_LEVEL,
+	       "PAP-8185: (%b %z) level too small",
+	       *pcom_father, *pcom_father);
+
+	/* Check whether the common parent is locked. */
+
+	if (buffer_locked(*pcom_father)) {
+
+		/* Release the write lock while the buffer is busy */
+		int depth = reiserfs_write_unlock_nested(tb->tb_sb);
+		__wait_on_buffer(*pcom_father);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
+		if (FILESYSTEM_CHANGED_TB(tb)) {
+			brelse(*pcom_father);
+			return REPEAT_SEARCH;
+		}
+	}
+
+	/*
+	 * So, we got common parent of the current node and its
+	 * left/right neighbor.  Now we are getting the parent of the
+	 * left/right neighbor.
+	 */
+
+	/* Form key to get parent of the left/right neighbor. */
+	le_key2cpu_key(&s_lr_father_key,
+		       internal_key(*pcom_father,
+				      (c_lr_par ==
+				       LEFT_PARENTS) ? (tb->lkey[h - 1] =
+							position -
+							1) : (tb->rkey[h -
+									   1] =
+							      position)));
+
+	if (c_lr_par == LEFT_PARENTS)
+		decrement_key(&s_lr_father_key);
+
+	if (search_by_key
+	    (tb->tb_sb, &s_lr_father_key, &s_path_to_neighbor_father,
+	     h + 1) == IO_ERROR)
+		/* path is released */
+		return IO_ERROR;
+
+	if (FILESYSTEM_CHANGED_TB(tb)) {
+		pathrelse(&s_path_to_neighbor_father);
+		brelse(*pcom_father);
+		return REPEAT_SEARCH;
+	}
+
+	*pfather = PATH_PLAST_BUFFER(&s_path_to_neighbor_father);
+
+	RFALSE(B_LEVEL(*pfather) != h + 1,
+	       "PAP-8190: (%b %z) level too small", *pfather, *pfather);
+	RFALSE(s_path_to_neighbor_father.path_length <
+	       FIRST_PATH_ELEMENT_OFFSET, "PAP-8192: path length is too small");
+
+	s_path_to_neighbor_father.path_length--;
+	pathrelse(&s_path_to_neighbor_father);
+	return CARRY_ON;
+}
+
+/*
+ * Get parents of neighbors of node in the path(S[path_offset]) and
+ * common parents of S[path_offset] and L[path_offset]/R[path_offset]:
+ * F[path_offset], FL[path_offset], FR[path_offset], CFL[path_offset],
+ * CFR[path_offset].
+ * Calculate numbers of left and right delimiting keys position:
+ * lkey[path_offset], rkey[path_offset].
+ * Returns:	SCHEDULE_OCCURRED - schedule occurred while the function worked
+ *	        CARRY_ON - schedule didn't occur while the function worked
+ */
+static int get_parents(struct tree_balance *tb, int h)
+{
+	struct treepath *path = tb->tb_path;
+	int position,
+	    ret,
+	    path_offset = PATH_H_PATH_OFFSET(tb->tb_path, h);
+	struct buffer_head *curf, *curcf;
+
+	/* Current node is the root of the tree or will be root of the tree */
+	if (path_offset <= FIRST_PATH_ELEMENT_OFFSET) {
+		/*
+		 * The root can not have parents.
+		 * Release nodes which previously were obtained as
+		 * parents of the current node neighbors.
+		 */
+		brelse(tb->FL[h]);
+		brelse(tb->CFL[h]);
+		brelse(tb->FR[h]);
+		brelse(tb->CFR[h]);
+		tb->FL[h]  = NULL;
+		tb->CFL[h] = NULL;
+		tb->FR[h]  = NULL;
+		tb->CFR[h] = NULL;
+		return CARRY_ON;
+	}
+
+	/* Get parent FL[path_offset] of L[path_offset]. */
+	position = PATH_OFFSET_POSITION(path, path_offset - 1);
+	if (position) {
+		/* Current node is not the first child of its parent. */
+		curf = PATH_OFFSET_PBUFFER(path, path_offset - 1);
+		curcf = PATH_OFFSET_PBUFFER(path, path_offset - 1);
+		get_bh(curf);
+		get_bh(curf);
+		tb->lkey[h] = position - 1;
+	} else {
+		/*
+		 * Calculate current parent of L[path_offset], which is the
+		 * left neighbor of the current node.  Calculate current
+		 * common parent of L[path_offset] and the current node.
+		 * Note that CFL[path_offset] not equal FL[path_offset] and
+		 * CFL[path_offset] not equal F[path_offset].
+		 * Calculate lkey[path_offset].
+		 */
+		if ((ret = get_far_parent(tb, h + 1, &curf,
+						  &curcf,
+						  LEFT_PARENTS)) != CARRY_ON)
+			return ret;
+	}
+
+	brelse(tb->FL[h]);
+	tb->FL[h] = curf;	/* New initialization of FL[h]. */
+	brelse(tb->CFL[h]);
+	tb->CFL[h] = curcf;	/* New initialization of CFL[h]. */
+
+	RFALSE((curf && !B_IS_IN_TREE(curf)) ||
+	       (curcf && !B_IS_IN_TREE(curcf)),
+	       "PAP-8195: FL (%b) or CFL (%b) is invalid", curf, curcf);
+
+	/* Get parent FR[h] of R[h]. */
+
+	/* Current node is the last child of F[h]. FR[h] != F[h]. */
+	if (position == B_NR_ITEMS(PATH_H_PBUFFER(path, h + 1))) {
+		/*
+		 * Calculate current parent of R[h], which is the right
+		 * neighbor of F[h].  Calculate current common parent of
+		 * R[h] and current node. Note that CFR[h] not equal
+		 * FR[path_offset] and CFR[h] not equal F[h].
+		 */
+		if ((ret =
+		     get_far_parent(tb, h + 1, &curf, &curcf,
+				    RIGHT_PARENTS)) != CARRY_ON)
+			return ret;
+	} else {
+		/* Current node is not the last child of its parent F[h]. */
+		curf = PATH_OFFSET_PBUFFER(path, path_offset - 1);
+		curcf = PATH_OFFSET_PBUFFER(path, path_offset - 1);
+		get_bh(curf);
+		get_bh(curf);
+		tb->rkey[h] = position;
+	}
+
+	brelse(tb->FR[h]);
+	/* New initialization of FR[path_offset]. */
+	tb->FR[h] = curf;
+
+	brelse(tb->CFR[h]);
+	/* New initialization of CFR[path_offset]. */
+	tb->CFR[h] = curcf;
+
+	RFALSE((curf && !B_IS_IN_TREE(curf)) ||
+	       (curcf && !B_IS_IN_TREE(curcf)),
+	       "PAP-8205: FR (%b) or CFR (%b) is invalid", curf, curcf);
+
+	return CARRY_ON;
+}
+
+/*
+ * it is possible to remove node as result of shiftings to
+ * neighbors even when we insert or paste item.
+ */
+static inline int can_node_be_removed(int mode, int lfree, int sfree, int rfree,
+				      struct tree_balance *tb, int h)
+{
+	struct buffer_head *Sh = PATH_H_PBUFFER(tb->tb_path, h);
+	int levbytes = tb->insert_size[h];
+	struct item_head *ih;
+	struct reiserfs_key *r_key = NULL;
+
+	ih = item_head(Sh, 0);
+	if (tb->CFR[h])
+		r_key = internal_key(tb->CFR[h], tb->rkey[h]);
+
+	if (lfree + rfree + sfree < MAX_CHILD_SIZE(Sh) + levbytes
+	    /* shifting may merge items which might save space */
+	    -
+	    ((!h
+	      && op_is_left_mergeable(&ih->ih_key, Sh->b_size)) ? IH_SIZE : 0)
+	    -
+	    ((!h && r_key
+	      && op_is_left_mergeable(r_key, Sh->b_size)) ? IH_SIZE : 0)
+	    + ((h) ? KEY_SIZE : 0)) {
+		/* node can not be removed */
+		if (sfree >= levbytes) {
+			/* new item fits into node S[h] without any shifting */
+			if (!h)
+				tb->s0num =
+				    B_NR_ITEMS(Sh) +
+				    ((mode == M_INSERT) ? 1 : 0);
+			set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+			return NO_BALANCING_NEEDED;
+		}
+	}
+	PROC_INFO_INC(tb->tb_sb, can_node_be_removed[h]);
+	return !NO_BALANCING_NEEDED;
+}
+
+/*
+ * Check whether current node S[h] is balanced when increasing its size by
+ * Inserting or Pasting.
+ * Calculate parameters for balancing for current level h.
+ * Parameters:
+ *	tb	tree_balance structure;
+ *	h	current level of the node;
+ *	inum	item number in S[h];
+ *	mode	i - insert, p - paste;
+ * Returns:	1 - schedule occurred;
+ *	        0 - balancing for higher levels needed;
+ *	       -1 - no balancing for higher levels needed;
+ *	       -2 - no disk space.
+ */
+/* ip means Inserting or Pasting */
+static int ip_check_balance(struct tree_balance *tb, int h)
+{
+	struct virtual_node *vn = tb->tb_vn;
+	/*
+	 * Number of bytes that must be inserted into (value is negative
+	 * if bytes are deleted) buffer which contains node being balanced.
+	 * The mnemonic is that the attempted change in node space used
+	 * level is levbytes bytes.
+	 */
+	int levbytes;
+	int ret;
+
+	int lfree, sfree, rfree /* free space in L, S and R */ ;
+
+	/*
+	 * nver is short for number of vertixes, and lnver is the number if
+	 * we shift to the left, rnver is the number if we shift to the
+	 * right, and lrnver is the number if we shift in both directions.
+	 * The goal is to minimize first the number of vertixes, and second,
+	 * the number of vertixes whose contents are changed by shifting,
+	 * and third the number of uncached vertixes whose contents are
+	 * changed by shifting and must be read from disk.
+	 */
+	int nver, lnver, rnver, lrnver;
+
+	/*
+	 * used at leaf level only, S0 = S[0] is the node being balanced,
+	 * sInum [ I = 0,1,2 ] is the number of items that will
+	 * remain in node SI after balancing.  S1 and S2 are new
+	 * nodes that might be created.
+	 */
+
+	/*
+	 * we perform 8 calls to get_num_ver().  For each call we
+	 * calculate five parameters.  where 4th parameter is s1bytes
+	 * and 5th - s2bytes
+	 *
+	 * s0num, s1num, s2num for 8 cases
+	 * 0,1 - do not shift and do not shift but bottle
+	 * 2   - shift only whole item to left
+	 * 3   - shift to left and bottle as much as possible
+	 * 4,5 - shift to right (whole items and as much as possible
+	 * 6,7 - shift to both directions (whole items and as much as possible)
+	 */
+	short snum012[40] = { 0, };
+
+	/* Sh is the node whose balance is currently being checked */
+	struct buffer_head *Sh;
+
+	Sh = PATH_H_PBUFFER(tb->tb_path, h);
+	levbytes = tb->insert_size[h];
+
+	/* Calculate balance parameters for creating new root. */
+	if (!Sh) {
+		if (!h)
+			reiserfs_panic(tb->tb_sb, "vs-8210",
+				       "S[0] can not be 0");
+		switch (ret = get_empty_nodes(tb, h)) {
+		/* no balancing for higher levels needed */
+		case CARRY_ON:
+			set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+			return NO_BALANCING_NEEDED;
+
+		case NO_DISK_SPACE:
+		case REPEAT_SEARCH:
+			return ret;
+		default:
+			reiserfs_panic(tb->tb_sb, "vs-8215", "incorrect "
+				       "return value of get_empty_nodes");
+		}
+	}
+
+	/* get parents of S[h] neighbors. */
+	ret = get_parents(tb, h);
+	if (ret != CARRY_ON)
+		return ret;
+
+	sfree = B_FREE_SPACE(Sh);
+
+	/* get free space of neighbors */
+	rfree = get_rfree(tb, h);
+	lfree = get_lfree(tb, h);
+
+	/* and new item fits into node S[h] without any shifting */
+	if (can_node_be_removed(vn->vn_mode, lfree, sfree, rfree, tb, h) ==
+	    NO_BALANCING_NEEDED)
+		return NO_BALANCING_NEEDED;
+
+	create_virtual_node(tb, h);
+
+	/*
+	 * determine maximal number of items we can shift to the left
+	 * neighbor (in tb structure) and the maximal number of bytes
+	 * that can flow to the left neighbor from the left most liquid
+	 * item that cannot be shifted from S[0] entirely (returned value)
+	 */
+	check_left(tb, h, lfree);
+
+	/*
+	 * determine maximal number of items we can shift to the right
+	 * neighbor (in tb structure) and the maximal number of bytes
+	 * that can flow to the right neighbor from the right most liquid
+	 * item that cannot be shifted from S[0] entirely (returned value)
+	 */
+	check_right(tb, h, rfree);
+
+	/*
+	 * all contents of internal node S[h] can be moved into its
+	 * neighbors, S[h] will be removed after balancing
+	 */
+	if (h && (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1)) {
+		int to_r;
+
+		/*
+		 * Since we are working on internal nodes, and our internal
+		 * nodes have fixed size entries, then we can balance by the
+		 * number of items rather than the space they consume.  In this
+		 * routine we set the left node equal to the right node,
+		 * allowing a difference of less than or equal to 1 child
+		 * pointer.
+		 */
+		to_r =
+		    ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - tb->rnum[h] +
+		     vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 -
+						tb->rnum[h]);
+		set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, 0, NULL,
+			       -1, -1);
+		return CARRY_ON;
+	}
+
+	/*
+	 * this checks balance condition, that any two neighboring nodes
+	 * can not fit in one node
+	 */
+	RFALSE(h &&
+	       (tb->lnum[h] >= vn->vn_nr_item + 1 ||
+		tb->rnum[h] >= vn->vn_nr_item + 1),
+	       "vs-8220: tree is not balanced on internal level");
+	RFALSE(!h && ((tb->lnum[h] >= vn->vn_nr_item && (tb->lbytes == -1)) ||
+		      (tb->rnum[h] >= vn->vn_nr_item && (tb->rbytes == -1))),
+	       "vs-8225: tree is not balanced on leaf level");
+
+	/*
+	 * all contents of S[0] can be moved into its neighbors
+	 * S[0] will be removed after balancing.
+	 */
+	if (!h && is_leaf_removable(tb))
+		return CARRY_ON;
+
+	/*
+	 * why do we perform this check here rather than earlier??
+	 * Answer: we can win 1 node in some cases above. Moreover we
+	 * checked it above, when we checked, that S[0] is not removable
+	 * in principle
+	 */
+
+	 /* new item fits into node S[h] without any shifting */
+	if (sfree >= levbytes) {
+		if (!h)
+			tb->s0num = vn->vn_nr_item;
+		set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+		return NO_BALANCING_NEEDED;
+	}
+
+	{
+		int lpar, rpar, nset, lset, rset, lrset;
+		/* regular overflowing of the node */
+
+		/*
+		 * get_num_ver works in 2 modes (FLOW & NO_FLOW)
+		 * lpar, rpar - number of items we can shift to left/right
+		 *              neighbor (including splitting item)
+		 * nset, lset, rset, lrset - shows, whether flowing items
+		 *                           give better packing
+		 */
+#define FLOW 1
+#define NO_FLOW 0		/* do not any splitting */
+
+		/* we choose one of the following */
+#define NOTHING_SHIFT_NO_FLOW	0
+#define NOTHING_SHIFT_FLOW	5
+#define LEFT_SHIFT_NO_FLOW	10
+#define LEFT_SHIFT_FLOW		15
+#define RIGHT_SHIFT_NO_FLOW	20
+#define RIGHT_SHIFT_FLOW	25
+#define LR_SHIFT_NO_FLOW	30
+#define LR_SHIFT_FLOW		35
+
+		lpar = tb->lnum[h];
+		rpar = tb->rnum[h];
+
+		/*
+		 * calculate number of blocks S[h] must be split into when
+		 * nothing is shifted to the neighbors, as well as number of
+		 * items in each part of the split node (s012 numbers),
+		 * and number of bytes (s1bytes) of the shared drop which
+		 * flow to S1 if any
+		 */
+		nset = NOTHING_SHIFT_NO_FLOW;
+		nver = get_num_ver(vn->vn_mode, tb, h,
+				   0, -1, h ? vn->vn_nr_item : 0, -1,
+				   snum012, NO_FLOW);
+
+		if (!h) {
+			int nver1;
+
+			/*
+			 * note, that in this case we try to bottle
+			 * between S[0] and S1 (S1 - the first new node)
+			 */
+			nver1 = get_num_ver(vn->vn_mode, tb, h,
+					    0, -1, 0, -1,
+					    snum012 + NOTHING_SHIFT_FLOW, FLOW);
+			if (nver > nver1)
+				nset = NOTHING_SHIFT_FLOW, nver = nver1;
+		}
+
+		/*
+		 * calculate number of blocks S[h] must be split into when
+		 * l_shift_num first items and l_shift_bytes of the right
+		 * most liquid item to be shifted are shifted to the left
+		 * neighbor, as well as number of items in each part of the
+		 * splitted node (s012 numbers), and number of bytes
+		 * (s1bytes) of the shared drop which flow to S1 if any
+		 */
+		lset = LEFT_SHIFT_NO_FLOW;
+		lnver = get_num_ver(vn->vn_mode, tb, h,
+				    lpar - ((h || tb->lbytes == -1) ? 0 : 1),
+				    -1, h ? vn->vn_nr_item : 0, -1,
+				    snum012 + LEFT_SHIFT_NO_FLOW, NO_FLOW);
+		if (!h) {
+			int lnver1;
+
+			lnver1 = get_num_ver(vn->vn_mode, tb, h,
+					     lpar -
+					     ((tb->lbytes != -1) ? 1 : 0),
+					     tb->lbytes, 0, -1,
+					     snum012 + LEFT_SHIFT_FLOW, FLOW);
+			if (lnver > lnver1)
+				lset = LEFT_SHIFT_FLOW, lnver = lnver1;
+		}
+
+		/*
+		 * calculate number of blocks S[h] must be split into when
+		 * r_shift_num first items and r_shift_bytes of the left most
+		 * liquid item to be shifted are shifted to the right neighbor,
+		 * as well as number of items in each part of the splitted
+		 * node (s012 numbers), and number of bytes (s1bytes) of the
+		 * shared drop which flow to S1 if any
+		 */
+		rset = RIGHT_SHIFT_NO_FLOW;
+		rnver = get_num_ver(vn->vn_mode, tb, h,
+				    0, -1,
+				    h ? (vn->vn_nr_item - rpar) : (rpar -
+								   ((tb->
+								     rbytes !=
+								     -1) ? 1 :
+								    0)), -1,
+				    snum012 + RIGHT_SHIFT_NO_FLOW, NO_FLOW);
+		if (!h) {
+			int rnver1;
+
+			rnver1 = get_num_ver(vn->vn_mode, tb, h,
+					     0, -1,
+					     (rpar -
+					      ((tb->rbytes != -1) ? 1 : 0)),
+					     tb->rbytes,
+					     snum012 + RIGHT_SHIFT_FLOW, FLOW);
+
+			if (rnver > rnver1)
+				rset = RIGHT_SHIFT_FLOW, rnver = rnver1;
+		}
+
+		/*
+		 * calculate number of blocks S[h] must be split into when
+		 * items are shifted in both directions, as well as number
+		 * of items in each part of the splitted node (s012 numbers),
+		 * and number of bytes (s1bytes) of the shared drop which
+		 * flow to S1 if any
+		 */
+		lrset = LR_SHIFT_NO_FLOW;
+		lrnver = get_num_ver(vn->vn_mode, tb, h,
+				     lpar - ((h || tb->lbytes == -1) ? 0 : 1),
+				     -1,
+				     h ? (vn->vn_nr_item - rpar) : (rpar -
+								    ((tb->
+								      rbytes !=
+								      -1) ? 1 :
+								     0)), -1,
+				     snum012 + LR_SHIFT_NO_FLOW, NO_FLOW);
+		if (!h) {
+			int lrnver1;
+
+			lrnver1 = get_num_ver(vn->vn_mode, tb, h,
+					      lpar -
+					      ((tb->lbytes != -1) ? 1 : 0),
+					      tb->lbytes,
+					      (rpar -
+					       ((tb->rbytes != -1) ? 1 : 0)),
+					      tb->rbytes,
+					      snum012 + LR_SHIFT_FLOW, FLOW);
+			if (lrnver > lrnver1)
+				lrset = LR_SHIFT_FLOW, lrnver = lrnver1;
+		}
+
+		/*
+		 * Our general shifting strategy is:
+		 * 1) to minimized number of new nodes;
+		 * 2) to minimized number of neighbors involved in shifting;
+		 * 3) to minimized number of disk reads;
+		 */
+
+		/* we can win TWO or ONE nodes by shifting in both directions */
+		if (lrnver < lnver && lrnver < rnver) {
+			RFALSE(h &&
+			       (tb->lnum[h] != 1 ||
+				tb->rnum[h] != 1 ||
+				lrnver != 1 || rnver != 2 || lnver != 2
+				|| h != 1), "vs-8230: bad h");
+			if (lrset == LR_SHIFT_FLOW)
+				set_parameters(tb, h, tb->lnum[h], tb->rnum[h],
+					       lrnver, snum012 + lrset,
+					       tb->lbytes, tb->rbytes);
+			else
+				set_parameters(tb, h,
+					       tb->lnum[h] -
+					       ((tb->lbytes == -1) ? 0 : 1),
+					       tb->rnum[h] -
+					       ((tb->rbytes == -1) ? 0 : 1),
+					       lrnver, snum012 + lrset, -1, -1);
+
+			return CARRY_ON;
+		}
+
+		/*
+		 * if shifting doesn't lead to better packing
+		 * then don't shift
+		 */
+		if (nver == lrnver) {
+			set_parameters(tb, h, 0, 0, nver, snum012 + nset, -1,
+				       -1);
+			return CARRY_ON;
+		}
+
+		/*
+		 * now we know that for better packing shifting in only one
+		 * direction either to the left or to the right is required
+		 */
+
+		/*
+		 * if shifting to the left is better than
+		 * shifting to the right
+		 */
+		if (lnver < rnver) {
+			SET_PAR_SHIFT_LEFT;
+			return CARRY_ON;
+		}
+
+		/*
+		 * if shifting to the right is better than
+		 * shifting to the left
+		 */
+		if (lnver > rnver) {
+			SET_PAR_SHIFT_RIGHT;
+			return CARRY_ON;
+		}
+
+		/*
+		 * now shifting in either direction gives the same number
+		 * of nodes and we can make use of the cached neighbors
+		 */
+		if (is_left_neighbor_in_cache(tb, h)) {
+			SET_PAR_SHIFT_LEFT;
+			return CARRY_ON;
+		}
+
+		/*
+		 * shift to the right independently on whether the
+		 * right neighbor in cache or not
+		 */
+		SET_PAR_SHIFT_RIGHT;
+		return CARRY_ON;
+	}
+}
+
+/*
+ * Check whether current node S[h] is balanced when Decreasing its size by
+ * Deleting or Cutting for INTERNAL node of S+tree.
+ * Calculate parameters for balancing for current level h.
+ * Parameters:
+ *	tb	tree_balance structure;
+ *	h	current level of the node;
+ *	inum	item number in S[h];
+ *	mode	i - insert, p - paste;
+ * Returns:	1 - schedule occurred;
+ *	        0 - balancing for higher levels needed;
+ *	       -1 - no balancing for higher levels needed;
+ *	       -2 - no disk space.
+ *
+ * Note: Items of internal nodes have fixed size, so the balance condition for
+ * the internal part of S+tree is as for the B-trees.
+ */
+static int dc_check_balance_internal(struct tree_balance *tb, int h)
+{
+	struct virtual_node *vn = tb->tb_vn;
+
+	/*
+	 * Sh is the node whose balance is currently being checked,
+	 * and Fh is its father.
+	 */
+	struct buffer_head *Sh, *Fh;
+	int ret;
+	int lfree, rfree /* free space in L and R */ ;
+
+	Sh = PATH_H_PBUFFER(tb->tb_path, h);
+	Fh = PATH_H_PPARENT(tb->tb_path, h);
+
+	/*
+	 * using tb->insert_size[h], which is negative in this case,
+	 * create_virtual_node calculates:
+	 * new_nr_item = number of items node would have if operation is
+	 * performed without balancing (new_nr_item);
+	 */
+	create_virtual_node(tb, h);
+
+	if (!Fh) {		/* S[h] is the root. */
+		/* no balancing for higher levels needed */
+		if (vn->vn_nr_item > 0) {
+			set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+			return NO_BALANCING_NEEDED;
+		}
+		/*
+		 * new_nr_item == 0.
+		 * Current root will be deleted resulting in
+		 * decrementing the tree height.
+		 */
+		set_parameters(tb, h, 0, 0, 0, NULL, -1, -1);
+		return CARRY_ON;
+	}
+
+	if ((ret = get_parents(tb, h)) != CARRY_ON)
+		return ret;
+
+	/* get free space of neighbors */
+	rfree = get_rfree(tb, h);
+	lfree = get_lfree(tb, h);
+
+	/* determine maximal number of items we can fit into neighbors */
+	check_left(tb, h, lfree);
+	check_right(tb, h, rfree);
+
+	/*
+	 * Balance condition for the internal node is valid.
+	 * In this case we balance only if it leads to better packing.
+	 */
+	if (vn->vn_nr_item >= MIN_NR_KEY(Sh)) {
+		/*
+		 * Here we join S[h] with one of its neighbors,
+		 * which is impossible with greater values of new_nr_item.
+		 */
+		if (vn->vn_nr_item == MIN_NR_KEY(Sh)) {
+			/* All contents of S[h] can be moved to L[h]. */
+			if (tb->lnum[h] >= vn->vn_nr_item + 1) {
+				int n;
+				int order_L;
+
+				order_L =
+				    ((n =
+				      PATH_H_B_ITEM_ORDER(tb->tb_path,
+							  h)) ==
+				     0) ? B_NR_ITEMS(tb->FL[h]) : n - 1;
+				n = dc_size(B_N_CHILD(tb->FL[h], order_L)) /
+				    (DC_SIZE + KEY_SIZE);
+				set_parameters(tb, h, -n - 1, 0, 0, NULL, -1,
+					       -1);
+				return CARRY_ON;
+			}
+
+			/* All contents of S[h] can be moved to R[h]. */
+			if (tb->rnum[h] >= vn->vn_nr_item + 1) {
+				int n;
+				int order_R;
+
+				order_R =
+				    ((n =
+				      PATH_H_B_ITEM_ORDER(tb->tb_path,
+							  h)) ==
+				     B_NR_ITEMS(Fh)) ? 0 : n + 1;
+				n = dc_size(B_N_CHILD(tb->FR[h], order_R)) /
+				    (DC_SIZE + KEY_SIZE);
+				set_parameters(tb, h, 0, -n - 1, 0, NULL, -1,
+					       -1);
+				return CARRY_ON;
+			}
+		}
+
+		/*
+		 * All contents of S[h] can be moved to the neighbors
+		 * (L[h] & R[h]).
+		 */
+		if (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1) {
+			int to_r;
+
+			to_r =
+			    ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] -
+			     tb->rnum[h] + vn->vn_nr_item + 1) / 2 -
+			    (MAX_NR_KEY(Sh) + 1 - tb->rnum[h]);
+			set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r,
+				       0, NULL, -1, -1);
+			return CARRY_ON;
+		}
+
+		/* Balancing does not lead to better packing. */
+		set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+		return NO_BALANCING_NEEDED;
+	}
+
+	/*
+	 * Current node contain insufficient number of items.
+	 * Balancing is required.
+	 */
+	/* Check whether we can merge S[h] with left neighbor. */
+	if (tb->lnum[h] >= vn->vn_nr_item + 1)
+		if (is_left_neighbor_in_cache(tb, h)
+		    || tb->rnum[h] < vn->vn_nr_item + 1 || !tb->FR[h]) {
+			int n;
+			int order_L;
+
+			order_L =
+			    ((n =
+			      PATH_H_B_ITEM_ORDER(tb->tb_path,
+						  h)) ==
+			     0) ? B_NR_ITEMS(tb->FL[h]) : n - 1;
+			n = dc_size(B_N_CHILD(tb->FL[h], order_L)) / (DC_SIZE +
+								      KEY_SIZE);
+			set_parameters(tb, h, -n - 1, 0, 0, NULL, -1, -1);
+			return CARRY_ON;
+		}
+
+	/* Check whether we can merge S[h] with right neighbor. */
+	if (tb->rnum[h] >= vn->vn_nr_item + 1) {
+		int n;
+		int order_R;
+
+		order_R =
+		    ((n =
+		      PATH_H_B_ITEM_ORDER(tb->tb_path,
+					  h)) == B_NR_ITEMS(Fh)) ? 0 : (n + 1);
+		n = dc_size(B_N_CHILD(tb->FR[h], order_R)) / (DC_SIZE +
+							      KEY_SIZE);
+		set_parameters(tb, h, 0, -n - 1, 0, NULL, -1, -1);
+		return CARRY_ON;
+	}
+
+	/* All contents of S[h] can be moved to the neighbors (L[h] & R[h]). */
+	if (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1) {
+		int to_r;
+
+		to_r =
+		    ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - tb->rnum[h] +
+		     vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 -
+						tb->rnum[h]);
+		set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, 0, NULL,
+			       -1, -1);
+		return CARRY_ON;
+	}
+
+	/* For internal nodes try to borrow item from a neighbor */
+	RFALSE(!tb->FL[h] && !tb->FR[h], "vs-8235: trying to borrow for root");
+
+	/* Borrow one or two items from caching neighbor */
+	if (is_left_neighbor_in_cache(tb, h) || !tb->FR[h]) {
+		int from_l;
+
+		from_l =
+		    (MAX_NR_KEY(Sh) + 1 - tb->lnum[h] + vn->vn_nr_item +
+		     1) / 2 - (vn->vn_nr_item + 1);
+		set_parameters(tb, h, -from_l, 0, 1, NULL, -1, -1);
+		return CARRY_ON;
+	}
+
+	set_parameters(tb, h, 0,
+		       -((MAX_NR_KEY(Sh) + 1 - tb->rnum[h] + vn->vn_nr_item +
+			  1) / 2 - (vn->vn_nr_item + 1)), 1, NULL, -1, -1);
+	return CARRY_ON;
+}
+
+/*
+ * Check whether current node S[h] is balanced when Decreasing its size by
+ * Deleting or Truncating for LEAF node of S+tree.
+ * Calculate parameters for balancing for current level h.
+ * Parameters:
+ *	tb	tree_balance structure;
+ *	h	current level of the node;
+ *	inum	item number in S[h];
+ *	mode	i - insert, p - paste;
+ * Returns:	1 - schedule occurred;
+ *	        0 - balancing for higher levels needed;
+ *	       -1 - no balancing for higher levels needed;
+ *	       -2 - no disk space.
+ */
+static int dc_check_balance_leaf(struct tree_balance *tb, int h)
+{
+	struct virtual_node *vn = tb->tb_vn;
+
+	/*
+	 * Number of bytes that must be deleted from
+	 * (value is negative if bytes are deleted) buffer which
+	 * contains node being balanced.  The mnemonic is that the
+	 * attempted change in node space used level is levbytes bytes.
+	 */
+	int levbytes;
+
+	/* the maximal item size */
+	int maxsize, ret;
+
+	/*
+	 * S0 is the node whose balance is currently being checked,
+	 * and F0 is its father.
+	 */
+	struct buffer_head *S0, *F0;
+	int lfree, rfree /* free space in L and R */ ;
+
+	S0 = PATH_H_PBUFFER(tb->tb_path, 0);
+	F0 = PATH_H_PPARENT(tb->tb_path, 0);
+
+	levbytes = tb->insert_size[h];
+
+	maxsize = MAX_CHILD_SIZE(S0);	/* maximal possible size of an item */
+
+	if (!F0) {		/* S[0] is the root now. */
+
+		RFALSE(-levbytes >= maxsize - B_FREE_SPACE(S0),
+		       "vs-8240: attempt to create empty buffer tree");
+
+		set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+		return NO_BALANCING_NEEDED;
+	}
+
+	if ((ret = get_parents(tb, h)) != CARRY_ON)
+		return ret;
+
+	/* get free space of neighbors */
+	rfree = get_rfree(tb, h);
+	lfree = get_lfree(tb, h);
+
+	create_virtual_node(tb, h);
+
+	/* if 3 leaves can be merge to one, set parameters and return */
+	if (are_leaves_removable(tb, lfree, rfree))
+		return CARRY_ON;
+
+	/*
+	 * determine maximal number of items we can shift to the left/right
+	 * neighbor and the maximal number of bytes that can flow to the
+	 * left/right neighbor from the left/right most liquid item that
+	 * cannot be shifted from S[0] entirely
+	 */
+	check_left(tb, h, lfree);
+	check_right(tb, h, rfree);
+
+	/* check whether we can merge S with left neighbor. */
+	if (tb->lnum[0] >= vn->vn_nr_item && tb->lbytes == -1)
+		if (is_left_neighbor_in_cache(tb, h) || ((tb->rnum[0] - ((tb->rbytes == -1) ? 0 : 1)) < vn->vn_nr_item) ||	/* S can not be merged with R */
+		    !tb->FR[h]) {
+
+			RFALSE(!tb->FL[h],
+			       "vs-8245: dc_check_balance_leaf: FL[h] must exist");
+
+			/* set parameter to merge S[0] with its left neighbor */
+			set_parameters(tb, h, -1, 0, 0, NULL, -1, -1);
+			return CARRY_ON;
+		}
+
+	/* check whether we can merge S[0] with right neighbor. */
+	if (tb->rnum[0] >= vn->vn_nr_item && tb->rbytes == -1) {
+		set_parameters(tb, h, 0, -1, 0, NULL, -1, -1);
+		return CARRY_ON;
+	}
+
+	/*
+	 * All contents of S[0] can be moved to the neighbors (L[0] & R[0]).
+	 * Set parameters and return
+	 */
+	if (is_leaf_removable(tb))
+		return CARRY_ON;
+
+	/* Balancing is not required. */
+	tb->s0num = vn->vn_nr_item;
+	set_parameters(tb, h, 0, 0, 1, NULL, -1, -1);
+	return NO_BALANCING_NEEDED;
+}
+
+/*
+ * Check whether current node S[h] is balanced when Decreasing its size by
+ * Deleting or Cutting.
+ * Calculate parameters for balancing for current level h.
+ * Parameters:
+ *	tb	tree_balance structure;
+ *	h	current level of the node;
+ *	inum	item number in S[h];
+ *	mode	d - delete, c - cut.
+ * Returns:	1 - schedule occurred;
+ *	        0 - balancing for higher levels needed;
+ *	       -1 - no balancing for higher levels needed;
+ *	       -2 - no disk space.
+ */
+static int dc_check_balance(struct tree_balance *tb, int h)
+{
+	RFALSE(!(PATH_H_PBUFFER(tb->tb_path, h)),
+	       "vs-8250: S is not initialized");
+
+	if (h)
+		return dc_check_balance_internal(tb, h);
+	else
+		return dc_check_balance_leaf(tb, h);
+}
+
+/*
+ * Check whether current node S[h] is balanced.
+ * Calculate parameters for balancing for current level h.
+ * Parameters:
+ *
+ *	tb	tree_balance structure:
+ *
+ *              tb is a large structure that must be read about in the header
+ *		file at the same time as this procedure if the reader is
+ *		to successfully understand this procedure
+ *
+ *	h	current level of the node;
+ *	inum	item number in S[h];
+ *	mode	i - insert, p - paste, d - delete, c - cut.
+ * Returns:	1 - schedule occurred;
+ *	        0 - balancing for higher levels needed;
+ *	       -1 - no balancing for higher levels needed;
+ *	       -2 - no disk space.
+ */
+static int check_balance(int mode,
+			 struct tree_balance *tb,
+			 int h,
+			 int inum,
+			 int pos_in_item,
+			 struct item_head *ins_ih, const void *data)
+{
+	struct virtual_node *vn;
+
+	vn = tb->tb_vn = (struct virtual_node *)(tb->vn_buf);
+	vn->vn_free_ptr = (char *)(tb->tb_vn + 1);
+	vn->vn_mode = mode;
+	vn->vn_affected_item_num = inum;
+	vn->vn_pos_in_item = pos_in_item;
+	vn->vn_ins_ih = ins_ih;
+	vn->vn_data = data;
+
+	RFALSE(mode == M_INSERT && !vn->vn_ins_ih,
+	       "vs-8255: ins_ih can not be 0 in insert mode");
+
+	/* Calculate balance parameters when size of node is increasing. */
+	if (tb->insert_size[h] > 0)
+		return ip_check_balance(tb, h);
+
+	/* Calculate balance parameters when  size of node is decreasing. */
+	return dc_check_balance(tb, h);
+}
+
+/* Check whether parent at the path is the really parent of the current node.*/
+static int get_direct_parent(struct tree_balance *tb, int h)
+{
+	struct buffer_head *bh;
+	struct treepath *path = tb->tb_path;
+	int position,
+	    path_offset = PATH_H_PATH_OFFSET(tb->tb_path, h);
+
+	/* We are in the root or in the new root. */
+	if (path_offset <= FIRST_PATH_ELEMENT_OFFSET) {
+
+		RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET - 1,
+		       "PAP-8260: invalid offset in the path");
+
+		if (PATH_OFFSET_PBUFFER(path, FIRST_PATH_ELEMENT_OFFSET)->
+		    b_blocknr == SB_ROOT_BLOCK(tb->tb_sb)) {
+			/* Root is not changed. */
+			PATH_OFFSET_PBUFFER(path, path_offset - 1) = NULL;
+			PATH_OFFSET_POSITION(path, path_offset - 1) = 0;
+			return CARRY_ON;
+		}
+		/* Root is changed and we must recalculate the path. */
+		return REPEAT_SEARCH;
+	}
+
+	/* Parent in the path is not in the tree. */
+	if (!B_IS_IN_TREE
+	    (bh = PATH_OFFSET_PBUFFER(path, path_offset - 1)))
+		return REPEAT_SEARCH;
+
+	if ((position =
+	     PATH_OFFSET_POSITION(path,
+				  path_offset - 1)) > B_NR_ITEMS(bh))
+		return REPEAT_SEARCH;
+
+	/* Parent in the path is not parent of the current node in the tree. */
+	if (B_N_CHILD_NUM(bh, position) !=
+	    PATH_OFFSET_PBUFFER(path, path_offset)->b_blocknr)
+		return REPEAT_SEARCH;
+
+	if (buffer_locked(bh)) {
+		int depth = reiserfs_write_unlock_nested(tb->tb_sb);
+		__wait_on_buffer(bh);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
+		if (FILESYSTEM_CHANGED_TB(tb))
+			return REPEAT_SEARCH;
+	}
+
+	/*
+	 * Parent in the path is unlocked and really parent
+	 * of the current node.
+	 */
+	return CARRY_ON;
+}
+
+/*
+ * Using lnum[h] and rnum[h] we should determine what neighbors
+ * of S[h] we
+ * need in order to balance S[h], and get them if necessary.
+ * Returns:	SCHEDULE_OCCURRED - schedule occurred while the function worked;
+ *	        CARRY_ON - schedule didn't occur while the function worked;
+ */
+static int get_neighbors(struct tree_balance *tb, int h)
+{
+	int child_position,
+	    path_offset = PATH_H_PATH_OFFSET(tb->tb_path, h + 1);
+	unsigned long son_number;
+	struct super_block *sb = tb->tb_sb;
+	struct buffer_head *bh;
+	int depth;
+
+	PROC_INFO_INC(sb, get_neighbors[h]);
+
+	if (tb->lnum[h]) {
+		/* We need left neighbor to balance S[h]. */
+		PROC_INFO_INC(sb, need_l_neighbor[h]);
+		bh = PATH_OFFSET_PBUFFER(tb->tb_path, path_offset);
+
+		RFALSE(bh == tb->FL[h] &&
+		       !PATH_OFFSET_POSITION(tb->tb_path, path_offset),
+		       "PAP-8270: invalid position in the parent");
+
+		child_position =
+		    (bh ==
+		     tb->FL[h]) ? tb->lkey[h] : B_NR_ITEMS(tb->
+								       FL[h]);
+		son_number = B_N_CHILD_NUM(tb->FL[h], child_position);
+		depth = reiserfs_write_unlock_nested(tb->tb_sb);
+		bh = sb_bread(sb, son_number);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
+		if (!bh)
+			return IO_ERROR;
+		if (FILESYSTEM_CHANGED_TB(tb)) {
+			brelse(bh);
+			PROC_INFO_INC(sb, get_neighbors_restart[h]);
+			return REPEAT_SEARCH;
+		}
+
+		RFALSE(!B_IS_IN_TREE(tb->FL[h]) ||
+		       child_position > B_NR_ITEMS(tb->FL[h]) ||
+		       B_N_CHILD_NUM(tb->FL[h], child_position) !=
+		       bh->b_blocknr, "PAP-8275: invalid parent");
+		RFALSE(!B_IS_IN_TREE(bh), "PAP-8280: invalid child");
+		RFALSE(!h &&
+		       B_FREE_SPACE(bh) !=
+		       MAX_CHILD_SIZE(bh) -
+		       dc_size(B_N_CHILD(tb->FL[0], child_position)),
+		       "PAP-8290: invalid child size of left neighbor");
+
+		brelse(tb->L[h]);
+		tb->L[h] = bh;
+	}
+
+	/* We need right neighbor to balance S[path_offset]. */
+	if (tb->rnum[h]) {
+		PROC_INFO_INC(sb, need_r_neighbor[h]);
+		bh = PATH_OFFSET_PBUFFER(tb->tb_path, path_offset);
+
+		RFALSE(bh == tb->FR[h] &&
+		       PATH_OFFSET_POSITION(tb->tb_path,
+					    path_offset) >=
+		       B_NR_ITEMS(bh),
+		       "PAP-8295: invalid position in the parent");
+
+		child_position =
+		    (bh == tb->FR[h]) ? tb->rkey[h] + 1 : 0;
+		son_number = B_N_CHILD_NUM(tb->FR[h], child_position);
+		depth = reiserfs_write_unlock_nested(tb->tb_sb);
+		bh = sb_bread(sb, son_number);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
+		if (!bh)
+			return IO_ERROR;
+		if (FILESYSTEM_CHANGED_TB(tb)) {
+			brelse(bh);
+			PROC_INFO_INC(sb, get_neighbors_restart[h]);
+			return REPEAT_SEARCH;
+		}
+		brelse(tb->R[h]);
+		tb->R[h] = bh;
+
+		RFALSE(!h
+		       && B_FREE_SPACE(bh) !=
+		       MAX_CHILD_SIZE(bh) -
+		       dc_size(B_N_CHILD(tb->FR[0], child_position)),
+		       "PAP-8300: invalid child size of right neighbor (%d != %d - %d)",
+		       B_FREE_SPACE(bh), MAX_CHILD_SIZE(bh),
+		       dc_size(B_N_CHILD(tb->FR[0], child_position)));
+
+	}
+	return CARRY_ON;
+}
+
+static int get_virtual_node_size(struct super_block *sb, struct buffer_head *bh)
+{
+	int max_num_of_items;
+	int max_num_of_entries;
+	unsigned long blocksize = sb->s_blocksize;
+
+#define MIN_NAME_LEN 1
+
+	max_num_of_items = (blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN);
+	max_num_of_entries = (blocksize - BLKH_SIZE - IH_SIZE) /
+	    (DEH_SIZE + MIN_NAME_LEN);
+
+	return sizeof(struct virtual_node) +
+	    max(max_num_of_items * sizeof(struct virtual_item),
+		sizeof(struct virtual_item) +
+		struct_size_t(struct direntry_uarea, entry_sizes,
+			      max_num_of_entries));
+}
+
+/*
+ * maybe we should fail balancing we are going to perform when kmalloc
+ * fails several times. But now it will loop until kmalloc gets
+ * required memory
+ */
+static int get_mem_for_virtual_node(struct tree_balance *tb)
+{
+	int check_fs = 0;
+	int size;
+	char *buf;
+
+	size = get_virtual_node_size(tb->tb_sb, PATH_PLAST_BUFFER(tb->tb_path));
+
+	/* we have to allocate more memory for virtual node */
+	if (size > tb->vn_buf_size) {
+		if (tb->vn_buf) {
+			/* free memory allocated before */
+			kfree(tb->vn_buf);
+			/* this is not needed if kfree is atomic */
+			check_fs = 1;
+		}
+
+		/* virtual node requires now more memory */
+		tb->vn_buf_size = size;
+
+		/* get memory for virtual item */
+		buf = kmalloc(size, GFP_ATOMIC | __GFP_NOWARN);
+		if (!buf) {
+			/*
+			 * getting memory with GFP_KERNEL priority may involve
+			 * balancing now (due to indirect_to_direct conversion
+			 * on dcache shrinking). So, release path and collected
+			 * resources here
+			 */
+			free_buffers_in_tb(tb);
+			buf = kmalloc(size, GFP_NOFS);
+			if (!buf) {
+				tb->vn_buf_size = 0;
+			}
+			tb->vn_buf = buf;
+			schedule();
+			return REPEAT_SEARCH;
+		}
+
+		tb->vn_buf = buf;
+	}
+
+	if (check_fs && FILESYSTEM_CHANGED_TB(tb))
+		return REPEAT_SEARCH;
+
+	return CARRY_ON;
+}
+
+#ifdef CONFIG_REISERFS_CHECK
+static void tb_buffer_sanity_check(struct super_block *sb,
+				   struct buffer_head *bh,
+				   const char *descr, int level)
+{
+	if (bh) {
+		if (atomic_read(&(bh->b_count)) <= 0)
+
+			reiserfs_panic(sb, "jmacd-1", "negative or zero "
+				       "reference counter for buffer %s[%d] "
+				       "(%b)", descr, level, bh);
+
+		if (!buffer_uptodate(bh))
+			reiserfs_panic(sb, "jmacd-2", "buffer is not up "
+				       "to date %s[%d] (%b)",
+				       descr, level, bh);
+
+		if (!B_IS_IN_TREE(bh))
+			reiserfs_panic(sb, "jmacd-3", "buffer is not "
+				       "in tree %s[%d] (%b)",
+				       descr, level, bh);
+
+		if (bh->b_bdev != sb->s_bdev)
+			reiserfs_panic(sb, "jmacd-4", "buffer has wrong "
+				       "device %s[%d] (%b)",
+				       descr, level, bh);
+
+		if (bh->b_size != sb->s_blocksize)
+			reiserfs_panic(sb, "jmacd-5", "buffer has wrong "
+				       "blocksize %s[%d] (%b)",
+				       descr, level, bh);
+
+		if (bh->b_blocknr > SB_BLOCK_COUNT(sb))
+			reiserfs_panic(sb, "jmacd-6", "buffer block "
+				       "number too high %s[%d] (%b)",
+				       descr, level, bh);
+	}
+}
+#else
+static void tb_buffer_sanity_check(struct super_block *sb,
+				   struct buffer_head *bh,
+				   const char *descr, int level)
+{;
+}
+#endif
+
+static int clear_all_dirty_bits(struct super_block *s, struct buffer_head *bh)
+{
+	return reiserfs_prepare_for_journal(s, bh, 0);
+}
+
+static int wait_tb_buffers_until_unlocked(struct tree_balance *tb)
+{
+	struct buffer_head *locked;
+#ifdef CONFIG_REISERFS_CHECK
+	int repeat_counter = 0;
+#endif
+	int i;
+
+	do {
+
+		locked = NULL;
+
+		for (i = tb->tb_path->path_length;
+		     !locked && i > ILLEGAL_PATH_ELEMENT_OFFSET; i--) {
+			if (PATH_OFFSET_PBUFFER(tb->tb_path, i)) {
+				/*
+				 * if I understand correctly, we can only
+				 * be sure the last buffer in the path is
+				 * in the tree --clm
+				 */
+#ifdef CONFIG_REISERFS_CHECK
+				if (PATH_PLAST_BUFFER(tb->tb_path) ==
+				    PATH_OFFSET_PBUFFER(tb->tb_path, i))
+					tb_buffer_sanity_check(tb->tb_sb,
+							       PATH_OFFSET_PBUFFER
+							       (tb->tb_path,
+								i), "S",
+							       tb->tb_path->
+							       path_length - i);
+#endif
+				if (!clear_all_dirty_bits(tb->tb_sb,
+							  PATH_OFFSET_PBUFFER
+							  (tb->tb_path,
+							   i))) {
+					locked =
+					    PATH_OFFSET_PBUFFER(tb->tb_path,
+								i);
+				}
+			}
+		}
+
+		for (i = 0; !locked && i < MAX_HEIGHT && tb->insert_size[i];
+		     i++) {
+
+			if (tb->lnum[i]) {
+
+				if (tb->L[i]) {
+					tb_buffer_sanity_check(tb->tb_sb,
+							       tb->L[i],
+							       "L", i);
+					if (!clear_all_dirty_bits
+					    (tb->tb_sb, tb->L[i]))
+						locked = tb->L[i];
+				}
+
+				if (!locked && tb->FL[i]) {
+					tb_buffer_sanity_check(tb->tb_sb,
+							       tb->FL[i],
+							       "FL", i);
+					if (!clear_all_dirty_bits
+					    (tb->tb_sb, tb->FL[i]))
+						locked = tb->FL[i];
+				}
+
+				if (!locked && tb->CFL[i]) {
+					tb_buffer_sanity_check(tb->tb_sb,
+							       tb->CFL[i],
+							       "CFL", i);
+					if (!clear_all_dirty_bits
+					    (tb->tb_sb, tb->CFL[i]))
+						locked = tb->CFL[i];
+				}
+
+			}
+
+			if (!locked && (tb->rnum[i])) {
+
+				if (tb->R[i]) {
+					tb_buffer_sanity_check(tb->tb_sb,
+							       tb->R[i],
+							       "R", i);
+					if (!clear_all_dirty_bits
+					    (tb->tb_sb, tb->R[i]))
+						locked = tb->R[i];
+				}
+
+				if (!locked && tb->FR[i]) {
+					tb_buffer_sanity_check(tb->tb_sb,
+							       tb->FR[i],
+							       "FR", i);
+					if (!clear_all_dirty_bits
+					    (tb->tb_sb, tb->FR[i]))
+						locked = tb->FR[i];
+				}
+
+				if (!locked && tb->CFR[i]) {
+					tb_buffer_sanity_check(tb->tb_sb,
+							       tb->CFR[i],
+							       "CFR", i);
+					if (!clear_all_dirty_bits
+					    (tb->tb_sb, tb->CFR[i]))
+						locked = tb->CFR[i];
+				}
+			}
+		}
+
+		/*
+		 * as far as I can tell, this is not required.  The FEB list
+		 * seems to be full of newly allocated nodes, which will
+		 * never be locked, dirty, or anything else.
+		 * To be safe, I'm putting in the checks and waits in.
+		 * For the moment, they are needed to keep the code in
+		 * journal.c from complaining about the buffer.
+		 * That code is inside CONFIG_REISERFS_CHECK as well.  --clm
+		 */
+		for (i = 0; !locked && i < MAX_FEB_SIZE; i++) {
+			if (tb->FEB[i]) {
+				if (!clear_all_dirty_bits
+				    (tb->tb_sb, tb->FEB[i]))
+					locked = tb->FEB[i];
+			}
+		}
+
+		if (locked) {
+			int depth;
+#ifdef CONFIG_REISERFS_CHECK
+			repeat_counter++;
+			if ((repeat_counter % 10000) == 0) {
+				reiserfs_warning(tb->tb_sb, "reiserfs-8200",
+						 "too many iterations waiting "
+						 "for buffer to unlock "
+						 "(%b)", locked);
+
+				/* Don't loop forever.  Try to recover from possible error. */
+
+				return (FILESYSTEM_CHANGED_TB(tb)) ?
+				    REPEAT_SEARCH : CARRY_ON;
+			}
+#endif
+			depth = reiserfs_write_unlock_nested(tb->tb_sb);
+			__wait_on_buffer(locked);
+			reiserfs_write_lock_nested(tb->tb_sb, depth);
+			if (FILESYSTEM_CHANGED_TB(tb))
+				return REPEAT_SEARCH;
+		}
+
+	} while (locked);
+
+	return CARRY_ON;
+}
+
+/*
+ * Prepare for balancing, that is
+ *	get all necessary parents, and neighbors;
+ *	analyze what and where should be moved;
+ *	get sufficient number of new nodes;
+ * Balancing will start only after all resources will be collected at a time.
+ *
+ * When ported to SMP kernels, only at the last moment after all needed nodes
+ * are collected in cache, will the resources be locked using the usual
+ * textbook ordered lock acquisition algorithms.  Note that ensuring that
+ * this code neither write locks what it does not need to write lock nor locks
+ * out of order will be a pain in the butt that could have been avoided.
+ * Grumble grumble. -Hans
+ *
+ * fix is meant in the sense of render unchanging
+ *
+ * Latency might be improved by first gathering a list of what buffers
+ * are needed and then getting as many of them in parallel as possible? -Hans
+ *
+ * Parameters:
+ *	op_mode	i - insert, d - delete, c - cut (truncate), p - paste (append)
+ *	tb	tree_balance structure;
+ *	inum	item number in S[h];
+ *      pos_in_item - comment this if you can
+ *      ins_ih	item head of item being inserted
+ *	data	inserted item or data to be pasted
+ * Returns:	1 - schedule occurred while the function worked;
+ *	        0 - schedule didn't occur while the function worked;
+ *             -1 - if no_disk_space
+ */
+
+int fix_nodes(int op_mode, struct tree_balance *tb,
+	      struct item_head *ins_ih, const void *data)
+{
+	int ret, h, item_num = PATH_LAST_POSITION(tb->tb_path);
+	int pos_in_item;
+
+	/*
+	 * we set wait_tb_buffers_run when we have to restore any dirty
+	 * bits cleared during wait_tb_buffers_run
+	 */
+	int wait_tb_buffers_run = 0;
+	struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+
+	++REISERFS_SB(tb->tb_sb)->s_fix_nodes;
+
+	pos_in_item = tb->tb_path->pos_in_item;
+
+	tb->fs_gen = get_generation(tb->tb_sb);
+
+	/*
+	 * we prepare and log the super here so it will already be in the
+	 * transaction when do_balance needs to change it.
+	 * This way do_balance won't have to schedule when trying to prepare
+	 * the super for logging
+	 */
+	reiserfs_prepare_for_journal(tb->tb_sb,
+				     SB_BUFFER_WITH_SB(tb->tb_sb), 1);
+	journal_mark_dirty(tb->transaction_handle,
+			   SB_BUFFER_WITH_SB(tb->tb_sb));
+	if (FILESYSTEM_CHANGED_TB(tb))
+		return REPEAT_SEARCH;
+
+	/* if it possible in indirect_to_direct conversion */
+	if (buffer_locked(tbS0)) {
+		int depth = reiserfs_write_unlock_nested(tb->tb_sb);
+		__wait_on_buffer(tbS0);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
+		if (FILESYSTEM_CHANGED_TB(tb))
+			return REPEAT_SEARCH;
+	}
+#ifdef CONFIG_REISERFS_CHECK
+	if (REISERFS_SB(tb->tb_sb)->cur_tb) {
+		print_cur_tb("fix_nodes");
+		reiserfs_panic(tb->tb_sb, "PAP-8305",
+			       "there is pending do_balance");
+	}
+
+	if (!buffer_uptodate(tbS0) || !B_IS_IN_TREE(tbS0))
+		reiserfs_panic(tb->tb_sb, "PAP-8320", "S[0] (%b %z) is "
+			       "not uptodate at the beginning of fix_nodes "
+			       "or not in tree (mode %c)",
+			       tbS0, tbS0, op_mode);
+
+	/* Check parameters. */
+	switch (op_mode) {
+	case M_INSERT:
+		if (item_num <= 0 || item_num > B_NR_ITEMS(tbS0))
+			reiserfs_panic(tb->tb_sb, "PAP-8330", "Incorrect "
+				       "item number %d (in S0 - %d) in case "
+				       "of insert", item_num,
+				       B_NR_ITEMS(tbS0));
+		break;
+	case M_PASTE:
+	case M_DELETE:
+	case M_CUT:
+		if (item_num < 0 || item_num >= B_NR_ITEMS(tbS0)) {
+			print_block(tbS0, 0, -1, -1);
+			reiserfs_panic(tb->tb_sb, "PAP-8335", "Incorrect "
+				       "item number(%d); mode = %c "
+				       "insert_size = %d",
+				       item_num, op_mode,
+				       tb->insert_size[0]);
+		}
+		break;
+	default:
+		reiserfs_panic(tb->tb_sb, "PAP-8340", "Incorrect mode "
+			       "of operation");
+	}
+#endif
+
+	if (get_mem_for_virtual_node(tb) == REPEAT_SEARCH)
+		/* FIXME: maybe -ENOMEM when tb->vn_buf == 0? Now just repeat */
+		return REPEAT_SEARCH;
+
+	/* Starting from the leaf level; for all levels h of the tree. */
+	for (h = 0; h < MAX_HEIGHT && tb->insert_size[h]; h++) {
+		ret = get_direct_parent(tb, h);
+		if (ret != CARRY_ON)
+			goto repeat;
+
+		ret = check_balance(op_mode, tb, h, item_num,
+				    pos_in_item, ins_ih, data);
+		if (ret != CARRY_ON) {
+			if (ret == NO_BALANCING_NEEDED) {
+				/* No balancing for higher levels needed. */
+				ret = get_neighbors(tb, h);
+				if (ret != CARRY_ON)
+					goto repeat;
+				if (h != MAX_HEIGHT - 1)
+					tb->insert_size[h + 1] = 0;
+				/*
+				 * ok, analysis and resource gathering
+				 * are complete
+				 */
+				break;
+			}
+			goto repeat;
+		}
+
+		ret = get_neighbors(tb, h);
+		if (ret != CARRY_ON)
+			goto repeat;
+
+		/*
+		 * No disk space, or schedule occurred and analysis may be
+		 * invalid and needs to be redone.
+		 */
+		ret = get_empty_nodes(tb, h);
+		if (ret != CARRY_ON)
+			goto repeat;
+
+		/*
+		 * We have a positive insert size but no nodes exist on this
+		 * level, this means that we are creating a new root.
+		 */
+		if (!PATH_H_PBUFFER(tb->tb_path, h)) {
+
+			RFALSE(tb->blknum[h] != 1,
+			       "PAP-8350: creating new empty root");
+
+			if (h < MAX_HEIGHT - 1)
+				tb->insert_size[h + 1] = 0;
+		} else if (!PATH_H_PBUFFER(tb->tb_path, h + 1)) {
+			/*
+			 * The tree needs to be grown, so this node S[h]
+			 * which is the root node is split into two nodes,
+			 * and a new node (S[h+1]) will be created to
+			 * become the root node.
+			 */
+			if (tb->blknum[h] > 1) {
+
+				RFALSE(h == MAX_HEIGHT - 1,
+				       "PAP-8355: attempt to create too high of a tree");
+
+				tb->insert_size[h + 1] =
+				    (DC_SIZE +
+				     KEY_SIZE) * (tb->blknum[h] - 1) +
+				    DC_SIZE;
+			} else if (h < MAX_HEIGHT - 1)
+				tb->insert_size[h + 1] = 0;
+		} else
+			tb->insert_size[h + 1] =
+			    (DC_SIZE + KEY_SIZE) * (tb->blknum[h] - 1);
+	}
+
+	ret = wait_tb_buffers_until_unlocked(tb);
+	if (ret == CARRY_ON) {
+		if (FILESYSTEM_CHANGED_TB(tb)) {
+			wait_tb_buffers_run = 1;
+			ret = REPEAT_SEARCH;
+			goto repeat;
+		} else {
+			return CARRY_ON;
+		}
+	} else {
+		wait_tb_buffers_run = 1;
+		goto repeat;
+	}
+
+repeat:
+	/*
+	 * fix_nodes was unable to perform its calculation due to
+	 * filesystem got changed under us, lack of free disk space or i/o
+	 * failure. If the first is the case - the search will be
+	 * repeated. For now - free all resources acquired so far except
+	 * for the new allocated nodes
+	 */
+	{
+		int i;
+
+		/* Release path buffers. */
+		if (wait_tb_buffers_run) {
+			pathrelse_and_restore(tb->tb_sb, tb->tb_path);
+		} else {
+			pathrelse(tb->tb_path);
+		}
+		/* brelse all resources collected for balancing */
+		for (i = 0; i < MAX_HEIGHT; i++) {
+			if (wait_tb_buffers_run) {
+				reiserfs_restore_prepared_buffer(tb->tb_sb,
+								 tb->L[i]);
+				reiserfs_restore_prepared_buffer(tb->tb_sb,
+								 tb->R[i]);
+				reiserfs_restore_prepared_buffer(tb->tb_sb,
+								 tb->FL[i]);
+				reiserfs_restore_prepared_buffer(tb->tb_sb,
+								 tb->FR[i]);
+				reiserfs_restore_prepared_buffer(tb->tb_sb,
+								 tb->
+								 CFL[i]);
+				reiserfs_restore_prepared_buffer(tb->tb_sb,
+								 tb->
+								 CFR[i]);
+			}
+
+			brelse(tb->L[i]);
+			brelse(tb->R[i]);
+			brelse(tb->FL[i]);
+			brelse(tb->FR[i]);
+			brelse(tb->CFL[i]);
+			brelse(tb->CFR[i]);
+
+			tb->L[i] = NULL;
+			tb->R[i] = NULL;
+			tb->FL[i] = NULL;
+			tb->FR[i] = NULL;
+			tb->CFL[i] = NULL;
+			tb->CFR[i] = NULL;
+		}
+
+		if (wait_tb_buffers_run) {
+			for (i = 0; i < MAX_FEB_SIZE; i++) {
+				if (tb->FEB[i])
+					reiserfs_restore_prepared_buffer
+					    (tb->tb_sb, tb->FEB[i]);
+			}
+		}
+		return ret;
+	}
+
+}
+
+void unfix_nodes(struct tree_balance *tb)
+{
+	int i;
+
+	/* Release path buffers. */
+	pathrelse_and_restore(tb->tb_sb, tb->tb_path);
+
+	/* brelse all resources collected for balancing */
+	for (i = 0; i < MAX_HEIGHT; i++) {
+		reiserfs_restore_prepared_buffer(tb->tb_sb, tb->L[i]);
+		reiserfs_restore_prepared_buffer(tb->tb_sb, tb->R[i]);
+		reiserfs_restore_prepared_buffer(tb->tb_sb, tb->FL[i]);
+		reiserfs_restore_prepared_buffer(tb->tb_sb, tb->FR[i]);
+		reiserfs_restore_prepared_buffer(tb->tb_sb, tb->CFL[i]);
+		reiserfs_restore_prepared_buffer(tb->tb_sb, tb->CFR[i]);
+
+		brelse(tb->L[i]);
+		brelse(tb->R[i]);
+		brelse(tb->FL[i]);
+		brelse(tb->FR[i]);
+		brelse(tb->CFL[i]);
+		brelse(tb->CFR[i]);
+	}
+
+	/* deal with list of allocated (used and unused) nodes */
+	for (i = 0; i < MAX_FEB_SIZE; i++) {
+		if (tb->FEB[i]) {
+			b_blocknr_t blocknr = tb->FEB[i]->b_blocknr;
+			/*
+			 * de-allocated block which was not used by
+			 * balancing and bforget about buffer for it
+			 */
+			brelse(tb->FEB[i]);
+			reiserfs_free_block(tb->transaction_handle, NULL,
+					    blocknr, 0);
+		}
+		if (tb->used[i]) {
+			/* release used as new nodes including a new root */
+			brelse(tb->used[i]);
+		}
+	}
+
+	kfree(tb->vn_buf);
+
+}