Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2518 insertions, 0 deletions

diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c
new file mode 100644
index 00000000000..e4f64be9e15
--- /dev/null
+++ b/fs/reiserfs/fix_node.c
@@ -0,0 +1,2518 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+
+/**
+ ** old_item_num
+ ** old_entry_num
+ ** set_entry_sizes
+ ** create_virtual_node
+ ** check_left
+ ** check_right
+ ** directory_part_size
+ ** get_num_ver
+ ** set_parameters
+ ** is_leaf_removable
+ ** are_leaves_removable
+ ** get_empty_nodes
+ ** get_lfree
+ ** get_rfree
+ ** is_left_neighbor_in_cache
+ ** decrement_key
+ ** get_far_parent
+ ** get_parents
+ ** can_node_be_removed
+ ** ip_check_balance
+ ** dc_check_balance_internal
+ ** dc_check_balance_leaf
+ ** dc_check_balance
+ ** check_balance
+ ** get_direct_parent
+ ** get_neighbors
+ ** fix_nodes
+ ** 
+ ** 
+ **/
+
+
+#include <linux/config.h>
+#include <linux/time.h>
+#include <linux/string.h>
+#include <linux/reiserfs_fs.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. */
+
+
+/* taking 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 = B_N_PITEM_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 those 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 = B_I_PITEM (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: create_virtual_node: "
+			    "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];
+	    vi->vi_new_data = vn->vn_data; // pointer to data which is going to be pasted
+	}
+    }
+
+  
+    /* 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 == 0,
+		"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 = B_N_PDELIM_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 (B_N_PITEM_HEAD (Sh, 0)) &&
+		  I_ENTRY_COUNT (B_N_PITEM_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: create_virtual_node: rdkey %k, affected item==%d (mode==%c) Must be %c", 
+				key, vn->vn_affected_item_num, vn->vn_mode, M_DELETE);
+	    } else
+		/* we can delete directory item, that has only one directory entry in it */
+		;
+	}
+#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 */
+	if (cur_free <= ih_size) {
+	    /* cannot shift even a part of the current item */
+	    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 */
+	if ( cur_free <= ih_size ) {    /* cannot shift even a part of the current item */
+	    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 cur_free;
+    //    int bytes;
+    int units;
+    struct virtual_node * vn = tb->tb_vn;
+    //    struct virtual_item * vi;
+
+    int total_node_size, max_node_size, current_item_size;
+    int needed_nodes;
+    int start_item, 	/* position of item we start filling node from */
+	end_item,	/* position of item we finish filling node by */
+	start_bytes,/* number of first bytes (entries for directory) of start_item-th item 
+		       we do not include into node that is being filled */
+	end_bytes;	/* number of last bytes (entries for directory) of end_item-th item 
+			   we do node include into node that is being filled */
+    int split_item_positions[2]; /* these are positions in virtual item of
+				    items, that are split between S[0] and
+				    S1new and S1new and S2new */
+
+    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;
+    cur_free = max_node_size;
+
+    // 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;
+	}
+
+	if (current_item_size > max_node_size) {
+	    /* virtual item length is longer, than max size of item in
+               a node. It is impossible for direct item */
+	    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;
+	}
+
+	if (!flow) {
+	    /* as we do not split items, take new node and continue */
+	    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);
+	    if (units == -1) {
+		/* nothing fits into current node, take new node and continue */
+		needed_nodes ++, i--, total_node_size = 0;
+		continue;
+	    }
+	}
+
+	/* something fits into the current node */
+	//if (snum012[3] != -1 || needed_nodes != 1)
+	//  reiserfs_panic (tb->tb_sb, "vs-8115: get_num_ver: too many nodes required");
+	//snum012[needed_nodes - 1 + 3] = op_unit_num (vi) - start_bytes - units;
+	start_bytes += units;
+	snum012[needed_nodes - 1 + 3] = units;
+
+	if (needed_nodes > 2)
+	    reiserfs_warning (tb->tb_sb, "vs-8111: get_num_ver: "
+			      "split_item_position is out of boundary");
+	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: get_num_ver: 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;
+}
+
+
+#ifdef CONFIG_REISERFS_CHECK
+extern struct tree_balance * cur_tb;
+#endif
+
+
+/* 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
+ *		not shifted entirely
+ *	rbytes	number of bytes which flow to the right neighbor from the item that is not
+ *		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;
+
+  if (h == 0)
+    {  /* only for leaf level */
+      if (s012 != NULL)
+	{
+	  tb->s0num = * s012 ++,
+	  tb->s1num = * s012 ++,
+	  tb->s2num = * s012 ++;
+	  tb->s1bytes = * s012 ++;
+	  tb->s2bytes = * 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, does node disappear 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);
+
+  if (remain_items < 1) {
+    /* all content of node can be shifted to neighbors */
+    set_parameters (tb, 0, to_left, vn->vn_nr_item - to_left, 0, NULL, -1, -1);    
+    return 1;
+  }
+  
+  if (remain_items > 1 || tb->lbytes == -1 || tb->rbytes == -1)
+    /* S[0] is not removable */
+    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 = B_N_PITEM_HEAD (S0, 0);
+    if (tb->CFR[0] && !comp_short_le_keys (&(ih->ih_key), B_N_PDELIM_KEY (tb->CFR[0], tb->rkey[0])))
+	if (is_direntry_le_ih (ih)) {
+	    /* 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 */
+	    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 * p_s_tb
+		       ) {
+  int n_counter;
+
+  decrement_counters_in_path(p_s_tb->tb_path);
+  
+  for ( n_counter = 0; n_counter < MAX_HEIGHT; n_counter++ ) {
+    decrement_bcount(p_s_tb->L[n_counter]);
+    p_s_tb->L[n_counter] = NULL;
+    decrement_bcount(p_s_tb->R[n_counter]);
+    p_s_tb->R[n_counter] = NULL;
+    decrement_bcount(p_s_tb->FL[n_counter]);
+    p_s_tb->FL[n_counter] = NULL;
+    decrement_bcount(p_s_tb->FR[n_counter]);
+    p_s_tb->FR[n_counter] = NULL;
+    decrement_bcount(p_s_tb->CFL[n_counter]);
+    p_s_tb->CFL[n_counter] = NULL;
+    decrement_bcount(p_s_tb->CFR[n_counter]);
+    p_s_tb->CFR[n_counter] = 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 * p_s_tb,
+              int n_h
+            ) {
+  struct buffer_head  * p_s_new_bh,
+    		      *	p_s_Sh = PATH_H_PBUFFER (p_s_tb->tb_path, n_h);
+  b_blocknr_t	      *	p_n_blocknr,
+    			a_n_blocknrs[MAX_AMOUNT_NEEDED] = {0, };
+  int       		n_counter,
+   			n_number_of_freeblk,
+                	n_amount_needed,/* number of needed empty blocks */
+			n_retval = CARRY_ON;
+  struct super_block *	p_s_sb = p_s_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
+     (n_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 n_h. */
+  /* blknum includes S[n_h], so we subtract 1 in this calculation */
+  for ( n_counter = 0, n_number_of_freeblk = p_s_tb->cur_blknum; n_counter < n_h; n_counter++ )
+    n_number_of_freeblk -= ( p_s_tb->blknum[n_counter] ) ? (p_s_tb->blknum[n_counter] - 1) : 0;
+
+  /* Allocate missing empty blocks. */
+  /* if p_s_Sh == 0  then we are getting a new root */
+  n_amount_needed = ( p_s_Sh ) ? (p_s_tb->blknum[n_h] - 1) : 1;
+  /*  Amount_needed = the amount that we need more than the amount that we have. */
+  if ( n_amount_needed > n_number_of_freeblk )
+    n_amount_needed -= n_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 (p_s_tb, a_n_blocknrs,
+                                   n_amount_needed) == NO_DISK_SPACE)
+    return NO_DISK_SPACE;
+
+  /* for each blocknumber we just got, get a buffer and stick it on FEB */
+  for ( p_n_blocknr = a_n_blocknrs, n_counter = 0; n_counter < n_amount_needed;
+	p_n_blocknr++, n_counter++ ) { 
+
+    RFALSE( ! *p_n_blocknr,
+	    "PAP-8135: reiserfs_new_blocknrs failed when got new blocks");
+
+    p_s_new_bh = sb_getblk(p_s_sb, *p_n_blocknr);
+    RFALSE (buffer_dirty (p_s_new_bh) ||
+	    buffer_journaled (p_s_new_bh) ||
+	    buffer_journal_dirty (p_s_new_bh),
+	    "PAP-8140: journlaled or dirty buffer %b for the new block", 
+	    p_s_new_bh);
+    
+    /* Put empty buffers into the array. */
+    RFALSE (p_s_tb->FEB[p_s_tb->cur_blknum],
+	    "PAP-8141: busy slot for new buffer");
+
+    set_buffer_journal_new (p_s_new_bh);
+    p_s_tb->FEB[p_s_tb->cur_blknum++] = p_s_new_bh;
+  }
+
+  if ( n_retval == CARRY_ON && FILESYSTEM_CHANGED_TB (p_s_tb) )
+    n_retval = REPEAT_SEARCH ;
+
+  return n_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)) == 0 || (l = tb->FL[h]) == 0)
+	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)) == 0 || (r = tb->FR[h]) == 0)
+    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 * p_s_tb,
+              int                   n_h
+            ) {
+  struct buffer_head  * p_s_father, * left;
+  struct super_block  * p_s_sb = p_s_tb->tb_sb;
+  b_blocknr_t		n_left_neighbor_blocknr;
+  int                   n_left_neighbor_position;
+
+  if ( ! p_s_tb->FL[n_h] ) /* Father of the left neighbor does not exist. */
+    return 0;
+
+  /* Calculate father of the node to be balanced. */
+  p_s_father = PATH_H_PBUFFER(p_s_tb->tb_path, n_h + 1);
+
+  RFALSE( ! p_s_father || 
+	  ! B_IS_IN_TREE (p_s_father) || 
+	  ! B_IS_IN_TREE (p_s_tb->FL[n_h]) ||
+	  ! buffer_uptodate (p_s_father) || 
+	  ! buffer_uptodate (p_s_tb->FL[n_h]),
+	  "vs-8165: F[h] (%b) or FL[h] (%b) is invalid", 
+	  p_s_father, p_s_tb->FL[n_h]);
+
+
+  /* Get position of the pointer to the left neighbor into the left father. */
+  n_left_neighbor_position = ( p_s_father == p_s_tb->FL[n_h] ) ?
+                      p_s_tb->lkey[n_h] : B_NR_ITEMS (p_s_tb->FL[n_h]);
+  /* Get left neighbor block number. */
+  n_left_neighbor_blocknr = B_N_CHILD_NUM(p_s_tb->FL[n_h], n_left_neighbor_position);
+  /* Look for the left neighbor in the cache. */
+  if ( (left = sb_find_get_block(p_s_sb, n_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 * p_s_key)
+{
+    // call item specific function for this key
+    item_ops[cpu_key_k_type (p_s_key)]->decrement_key (p_s_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 *   p_s_tb,
+			    int                     n_h,
+			    struct buffer_head  **  pp_s_father,
+			    struct buffer_head  **  pp_s_com_father,
+			    char                    c_lr_par) 
+{
+    struct buffer_head  * p_s_parent;
+    INITIALIZE_PATH (s_path_to_neighbor_father);
+    struct path * p_s_path = p_s_tb->tb_path;
+    struct cpu_key	s_lr_father_key;
+    int                   n_counter,
+	n_position = INT_MAX,
+	n_first_last_position = 0,
+	n_path_offset = PATH_H_PATH_OFFSET(p_s_path, n_h);
+
+    /* Starting from F[n_h] go upwards in the tree, and look for the common
+      ancestor of F[n_h], and its neighbor l/r, that should be obtained. */
+
+    n_counter = n_path_offset;
+
+    RFALSE( n_counter < FIRST_PATH_ELEMENT_OFFSET,
+	    "PAP-8180: invalid path length");
+
+  
+    for ( ; n_counter > FIRST_PATH_ELEMENT_OFFSET; n_counter--  )  {
+	/* Check whether parent of the current buffer in the path is really parent in the tree. */
+	if ( ! B_IS_IN_TREE(p_s_parent = PATH_OFFSET_PBUFFER(p_s_path, n_counter - 1)) )
+	    return REPEAT_SEARCH;
+	/* Check whether position in the parent is correct. */
+	if ( (n_position = PATH_OFFSET_POSITION(p_s_path, n_counter - 1)) > B_NR_ITEMS(p_s_parent) )
+	    return REPEAT_SEARCH;
+	/* Check whether parent at the path really points to the child. */
+	if ( B_N_CHILD_NUM(p_s_parent, n_position) !=
+	     PATH_OFFSET_PBUFFER(p_s_path, n_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 )
+	    n_first_last_position = B_NR_ITEMS (p_s_parent);
+	if ( n_position != n_first_last_position ) {
+	    *pp_s_com_father = p_s_parent;
+	    get_bh(*pp_s_com_father) ;
+	    /*(*pp_s_com_father = p_s_parent)->b_count++;*/
+	    break;
+	}
+    }
+
+    /* if we are in the root of the tree, then there is no common father */
+    if ( n_counter == FIRST_PATH_ELEMENT_OFFSET ) {
+	/* Check whether first buffer in the path is the root of the tree. */
+	if ( PATH_OFFSET_PBUFFER(p_s_tb->tb_path, FIRST_PATH_ELEMENT_OFFSET)->b_blocknr ==
+	     SB_ROOT_BLOCK (p_s_tb->tb_sb) ) {
+	    *pp_s_father = *pp_s_com_father = NULL;
+	    return CARRY_ON;
+	}
+	return REPEAT_SEARCH;
+    }
+
+    RFALSE( B_LEVEL (*pp_s_com_father) <= DISK_LEAF_NODE_LEVEL,
+	    "PAP-8185: (%b %z) level too small", 
+	    *pp_s_com_father, *pp_s_com_father);
+
+    /* Check whether the common parent is locked. */
+
+    if ( buffer_locked (*pp_s_com_father) ) {
+	__wait_on_buffer(*pp_s_com_father);
+	if ( FILESYSTEM_CHANGED_TB (p_s_tb) ) {
+	    decrement_bcount(*pp_s_com_father);
+	    return REPEAT_SEARCH;
+	}
+    }
+
+    /* So, we got common parent of the current node and its left/right neighbor.
+     Now we are geting the parent of the left/right neighbor. */
+
+    /* Form key to get parent of the left/right neighbor. */
+    le_key2cpu_key (&s_lr_father_key, B_N_PDELIM_KEY(*pp_s_com_father, ( c_lr_par == LEFT_PARENTS ) ?
+						     (p_s_tb->lkey[n_h - 1] = n_position - 1) : (p_s_tb->rkey[n_h - 1] = n_position)));
+
+
+    if ( c_lr_par == LEFT_PARENTS )
+	decrement_key(&s_lr_father_key);
+
+    if (search_by_key(p_s_tb->tb_sb, &s_lr_father_key, &s_path_to_neighbor_father, n_h + 1) == IO_ERROR)
+	// path is released
+	return IO_ERROR;
+
+    if ( FILESYSTEM_CHANGED_TB (p_s_tb) ) {
+	decrement_counters_in_path(&s_path_to_neighbor_father);
+	decrement_bcount(*pp_s_com_father);
+	return REPEAT_SEARCH;
+    }
+
+    *pp_s_father = PATH_PLAST_BUFFER(&s_path_to_neighbor_father);
+
+    RFALSE( B_LEVEL (*pp_s_father) !