Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / reiserfs / do_balan.c
diff --git a/kernel/fs/reiserfs/do_balan.c b/kernel/fs/reiserfs/do_balan.c
new file mode 100644 (file)
index 0000000..9c02d96
--- /dev/null
@@ -0,0 +1,1911 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+
+/*
+ * Now we have all buffers that must be used in balancing of the tree
+ * Further calculations can not cause schedule(), and thus the buffer
+ * tree will be stable until the balancing will be finished
+ * balance the tree according to the analysis made before,
+ * and using buffers obtained after all above.
+ */
+
+#include <linux/uaccess.h>
+#include <linux/time.h>
+#include "reiserfs.h"
+#include <linux/buffer_head.h>
+#include <linux/kernel.h>
+
+static inline void buffer_info_init_left(struct tree_balance *tb,
+                                         struct buffer_info *bi)
+{
+       bi->tb          = tb;
+       bi->bi_bh       = tb->L[0];
+       bi->bi_parent   = tb->FL[0];
+       bi->bi_position = get_left_neighbor_position(tb, 0);
+}
+
+static inline void buffer_info_init_right(struct tree_balance *tb,
+                                          struct buffer_info *bi)
+{
+       bi->tb          = tb;
+       bi->bi_bh       = tb->R[0];
+       bi->bi_parent   = tb->FR[0];
+       bi->bi_position = get_right_neighbor_position(tb, 0);
+}
+
+static inline void buffer_info_init_tbS0(struct tree_balance *tb,
+                                         struct buffer_info *bi)
+{
+       bi->tb          = tb;
+       bi->bi_bh        = PATH_PLAST_BUFFER(tb->tb_path);
+       bi->bi_parent   = PATH_H_PPARENT(tb->tb_path, 0);
+       bi->bi_position = PATH_H_POSITION(tb->tb_path, 1);
+}
+
+static inline void buffer_info_init_bh(struct tree_balance *tb,
+                                       struct buffer_info *bi,
+                                       struct buffer_head *bh)
+{
+       bi->tb          = tb;
+       bi->bi_bh       = bh;
+       bi->bi_parent   = NULL;
+       bi->bi_position = 0;
+}
+
+inline void do_balance_mark_leaf_dirty(struct tree_balance *tb,
+                                      struct buffer_head *bh, int flag)
+{
+       journal_mark_dirty(tb->transaction_handle, bh);
+}
+
+#define do_balance_mark_internal_dirty do_balance_mark_leaf_dirty
+#define do_balance_mark_sb_dirty do_balance_mark_leaf_dirty
+
+/*
+ * summary:
+ *  if deleting something ( tb->insert_size[0] < 0 )
+ *    return(balance_leaf_when_delete()); (flag d handled here)
+ *  else
+ *    if lnum is larger than 0 we put items into the left node
+ *    if rnum is larger than 0 we put items into the right node
+ *    if snum1 is larger than 0 we put items into the new node s1
+ *    if snum2 is larger than 0 we put items into the new node s2
+ * Note that all *num* count new items being created.
+ */
+
+static void balance_leaf_when_delete_del(struct tree_balance *tb)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int item_pos = PATH_LAST_POSITION(tb->tb_path);
+       struct buffer_info bi;
+#ifdef CONFIG_REISERFS_CHECK
+       struct item_head *ih = item_head(tbS0, item_pos);
+#endif
+
+       RFALSE(ih_item_len(ih) + IH_SIZE != -tb->insert_size[0],
+              "vs-12013: mode Delete, insert size %d, ih to be deleted %h",
+              -tb->insert_size[0], ih);
+
+       buffer_info_init_tbS0(tb, &bi);
+       leaf_delete_items(&bi, 0, item_pos, 1, -1);
+
+       if (!item_pos && tb->CFL[0]) {
+               if (B_NR_ITEMS(tbS0)) {
+                       replace_key(tb, tb->CFL[0], tb->lkey[0], tbS0, 0);
+               } else {
+                       if (!PATH_H_POSITION(tb->tb_path, 1))
+                               replace_key(tb, tb->CFL[0], tb->lkey[0],
+                                           PATH_H_PPARENT(tb->tb_path, 0), 0);
+               }
+       }
+
+       RFALSE(!item_pos && !tb->CFL[0],
+              "PAP-12020: tb->CFL[0]==%p, tb->L[0]==%p", tb->CFL[0],
+              tb->L[0]);
+}
+
+/* cut item in S[0] */
+static void balance_leaf_when_delete_cut(struct tree_balance *tb)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int item_pos = PATH_LAST_POSITION(tb->tb_path);
+       struct item_head *ih = item_head(tbS0, item_pos);
+       int pos_in_item = tb->tb_path->pos_in_item;
+       struct buffer_info bi;
+       buffer_info_init_tbS0(tb, &bi);
+
+       if (is_direntry_le_ih(ih)) {
+               /*
+                * UFS unlink semantics are such that you can only
+                * delete one directory entry at a time.
+                *
+                * when we cut a directory tb->insert_size[0] means
+                * number of entries to be cut (always 1)
+                */
+               tb->insert_size[0] = -1;
+               leaf_cut_from_buffer(&bi, item_pos, pos_in_item,
+                                    -tb->insert_size[0]);
+
+               RFALSE(!item_pos && !pos_in_item && !tb->CFL[0],
+                      "PAP-12030: can not change delimiting key. CFL[0]=%p",
+                      tb->CFL[0]);
+
+               if (!item_pos && !pos_in_item && tb->CFL[0])
+                       replace_key(tb, tb->CFL[0], tb->lkey[0], tbS0, 0);
+       } else {
+               leaf_cut_from_buffer(&bi, item_pos, pos_in_item,
+                                    -tb->insert_size[0]);
+
+               RFALSE(!ih_item_len(ih),
+                      "PAP-12035: cut must leave non-zero dynamic "
+                      "length of item");
+       }
+}
+
+static int balance_leaf_when_delete_left(struct tree_balance *tb)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+
+       /* L[0] must be joined with S[0] */
+       if (tb->lnum[0] == -1) {
+               /* R[0] must be also joined with S[0] */
+               if (tb->rnum[0] == -1) {
+                       if (tb->FR[0] == PATH_H_PPARENT(tb->tb_path, 0)) {
+                               /*
+                                * all contents of all the
+                                * 3 buffers will be in L[0]
+                                */
+                               if (PATH_H_POSITION(tb->tb_path, 1) == 0 &&
+                                   1 < B_NR_ITEMS(tb->FR[0]))
+                                       replace_key(tb, tb->CFL[0],
+                                                   tb->lkey[0], tb->FR[0], 1);
+
+                               leaf_move_items(LEAF_FROM_S_TO_L, tb, n, -1,
+                                               NULL);
+                               leaf_move_items(LEAF_FROM_R_TO_L, tb,
+                                               B_NR_ITEMS(tb->R[0]), -1,
+                                               NULL);
+
+                               reiserfs_invalidate_buffer(tb, tbS0);
+                               reiserfs_invalidate_buffer(tb, tb->R[0]);
+
+                               return 0;
+                       }
+
+                       /* all contents of all the 3 buffers will be in R[0] */
+                       leaf_move_items(LEAF_FROM_S_TO_R, tb, n, -1, NULL);
+                       leaf_move_items(LEAF_FROM_L_TO_R, tb,
+                                       B_NR_ITEMS(tb->L[0]), -1, NULL);
+
+                       /* right_delimiting_key is correct in R[0] */
+                       replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
+
+                       reiserfs_invalidate_buffer(tb, tbS0);
+                       reiserfs_invalidate_buffer(tb, tb->L[0]);
+
+                       return -1;
+               }
+
+               RFALSE(tb->rnum[0] != 0,
+                      "PAP-12045: rnum must be 0 (%d)", tb->rnum[0]);
+               /* all contents of L[0] and S[0] will be in L[0] */
+               leaf_shift_left(tb, n, -1);
+
+               reiserfs_invalidate_buffer(tb, tbS0);
+
+               return 0;
+       }
+
+       /*
+        * a part of contents of S[0] will be in L[0] and
+        * the rest part of S[0] will be in R[0]
+        */
+
+       RFALSE((tb->lnum[0] + tb->rnum[0] < n) ||
+              (tb->lnum[0] + tb->rnum[0] > n + 1),
+              "PAP-12050: rnum(%d) and lnum(%d) and item "
+              "number(%d) in S[0] are not consistent",
+              tb->rnum[0], tb->lnum[0], n);
+       RFALSE((tb->lnum[0] + tb->rnum[0] == n) &&
+              (tb->lbytes != -1 || tb->rbytes != -1),
+              "PAP-12055: bad rbytes (%d)/lbytes (%d) "
+              "parameters when items are not split",
+              tb->rbytes, tb->lbytes);
+       RFALSE((tb->lnum[0] + tb->rnum[0] == n + 1) &&
+              (tb->lbytes < 1 || tb->rbytes != -1),
+              "PAP-12060: bad rbytes (%d)/lbytes (%d) "
+              "parameters when items are split",
+              tb->rbytes, tb->lbytes);
+
+       leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
+       leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
+
+       reiserfs_invalidate_buffer(tb, tbS0);
+
+       return 0;
+}
+
+/*
+ * Balance leaf node in case of delete or cut: insert_size[0] < 0
+ *
+ * lnum, rnum can have values >= -1
+ *     -1 means that the neighbor must be joined with S
+ *      0 means that nothing should be done with the neighbor
+ *     >0 means to shift entirely or partly the specified number of items
+ *         to the neighbor
+ */
+static int balance_leaf_when_delete(struct tree_balance *tb, int flag)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int item_pos = PATH_LAST_POSITION(tb->tb_path);
+       struct buffer_info bi;
+       int n;
+       struct item_head *ih;
+
+       RFALSE(tb->FR[0] && B_LEVEL(tb->FR[0]) != DISK_LEAF_NODE_LEVEL + 1,
+              "vs- 12000: level: wrong FR %z", tb->FR[0]);
+       RFALSE(tb->blknum[0] > 1,
+              "PAP-12005: tb->blknum == %d, can not be > 1", tb->blknum[0]);
+       RFALSE(!tb->blknum[0] && !PATH_H_PPARENT(tb->tb_path, 0),
+              "PAP-12010: tree can not be empty");
+
+       ih = item_head(tbS0, item_pos);
+       buffer_info_init_tbS0(tb, &bi);
+
+       /* Delete or truncate the item */
+
+       BUG_ON(flag != M_DELETE && flag != M_CUT);
+       if (flag == M_DELETE)
+               balance_leaf_when_delete_del(tb);
+       else /* M_CUT */
+               balance_leaf_when_delete_cut(tb);
+
+
+       /*
+        * the rule is that no shifting occurs unless by shifting
+        * a node can be freed
+        */
+       n = B_NR_ITEMS(tbS0);
+
+
+       /* L[0] takes part in balancing */
+       if (tb->lnum[0])
+               return balance_leaf_when_delete_left(tb);
+
+       if (tb->rnum[0] == -1) {
+               /* all contents of R[0] and S[0] will be in R[0] */
+               leaf_shift_right(tb, n, -1);
+               reiserfs_invalidate_buffer(tb, tbS0);
+               return 0;
+       }
+
+       RFALSE(tb->rnum[0],
+              "PAP-12065: bad rnum parameter must be 0 (%d)", tb->rnum[0]);
+       return 0;
+}
+
+static unsigned int balance_leaf_insert_left(struct tree_balance *tb,
+                                            struct item_head *const ih,
+                                            const char * const body)
+{
+       int ret;
+       struct buffer_info bi;
+       int n = B_NR_ITEMS(tb->L[0]);
+       unsigned body_shift_bytes = 0;
+
+       if (tb->item_pos == tb->lnum[0] - 1 && tb->lbytes != -1) {
+               /* part of new item falls into L[0] */
+               int new_item_len, shift;
+               int version;
+
+               ret = leaf_shift_left(tb, tb->lnum[0] - 1, -1);
+
+               /* Calculate item length to insert to S[0] */
+               new_item_len = ih_item_len(ih) - tb->lbytes;
+
+               /* Calculate and check item length to insert to L[0] */
+               put_ih_item_len(ih, ih_item_len(ih) - new_item_len);
+
+               RFALSE(ih_item_len(ih) <= 0,
+                      "PAP-12080: there is nothing to insert into L[0]: "
+                      "ih_item_len=%d", ih_item_len(ih));
+
+               /* Insert new item into L[0] */
+               buffer_info_init_left(tb, &bi);
+               leaf_insert_into_buf(&bi, n + tb->item_pos - ret, ih, body,
+                            min_t(int, tb->zeroes_num, ih_item_len(ih)));
+
+               version = ih_version(ih);
+
+               /*
+                * Calculate key component, item length and body to
+                * insert into S[0]
+                */
+               shift = 0;
+               if (is_indirect_le_ih(ih))
+                       shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
+
+               add_le_ih_k_offset(ih, tb->lbytes << shift);
+
+               put_ih_item_len(ih, new_item_len);
+               if (tb->lbytes > tb->zeroes_num) {
+                       body_shift_bytes = tb->lbytes - tb->zeroes_num;
+                       tb->zeroes_num = 0;
+               } else
+                       tb->zeroes_num -= tb->lbytes;
+
+               RFALSE(ih_item_len(ih) <= 0,
+                      "PAP-12085: there is nothing to insert into S[0]: "
+                      "ih_item_len=%d", ih_item_len(ih));
+       } else {
+               /* new item in whole falls into L[0] */
+               /* Shift lnum[0]-1 items to L[0] */
+               ret = leaf_shift_left(tb, tb->lnum[0] - 1, tb->lbytes);
+
+               /* Insert new item into L[0] */
+               buffer_info_init_left(tb, &bi);
+               leaf_insert_into_buf(&bi, n + tb->item_pos - ret, ih, body,
+                                    tb->zeroes_num);
+               tb->insert_size[0] = 0;
+               tb->zeroes_num = 0;
+       }
+       return body_shift_bytes;
+}
+
+static void balance_leaf_paste_left_shift_dirent(struct tree_balance *tb,
+                                                struct item_head * const ih,
+                                                const char * const body)
+{
+       int n = B_NR_ITEMS(tb->L[0]);
+       struct buffer_info bi;
+
+       RFALSE(tb->zeroes_num,
+              "PAP-12090: invalid parameter in case of a directory");
+
+       /* directory item */
+       if (tb->lbytes > tb->pos_in_item) {
+               /* new directory entry falls into L[0] */
+               struct item_head *pasted;
+               int ret, l_pos_in_item = tb->pos_in_item;
+
+               /*
+                * Shift lnum[0] - 1 items in whole.
+                * Shift lbytes - 1 entries from given directory item
+                */
+               ret = leaf_shift_left(tb, tb->lnum[0], tb->lbytes - 1);
+               if (ret && !tb->item_pos) {
+                       pasted = item_head(tb->L[0], B_NR_ITEMS(tb->L[0]) - 1);
+                       l_pos_in_item += ih_entry_count(pasted) -
+                                        (tb->lbytes - 1);
+               }
+
+               /* Append given directory entry to directory item */
+               buffer_info_init_left(tb, &bi);
+               leaf_paste_in_buffer(&bi, n + tb->item_pos - ret,
+                                    l_pos_in_item, tb->insert_size[0],
+                                    body, tb->zeroes_num);
+
+               /*
+                * previous string prepared space for pasting new entry,
+                * following string pastes this entry
+                */
+
+               /*
+                * when we have merge directory item, pos_in_item
+                * has been changed too
+                */
+
+               /* paste new directory entry. 1 is entry number */
+               leaf_paste_entries(&bi, n + tb->item_pos - ret,
+                                  l_pos_in_item, 1,
+                                  (struct reiserfs_de_head *) body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+               tb->insert_size[0] = 0;
+       } else {
+               /* new directory item doesn't fall into L[0] */
+               /*
+                * Shift lnum[0]-1 items in whole. Shift lbytes
+                * directory entries from directory item number lnum[0]
+                */
+               leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
+       }
+
+       /* Calculate new position to append in item body */
+       tb->pos_in_item -= tb->lbytes;
+}
+
+static unsigned int balance_leaf_paste_left_shift(struct tree_balance *tb,
+                                                 struct item_head * const ih,
+                                                 const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tb->L[0]);
+       struct buffer_info bi;
+       int body_shift_bytes = 0;
+
+       if (is_direntry_le_ih(item_head(tbS0, tb->item_pos))) {
+               balance_leaf_paste_left_shift_dirent(tb, ih, body);
+               return 0;
+       }
+
+       RFALSE(tb->lbytes <= 0,
+              "PAP-12095: there is nothing to shift to L[0]. "
+              "lbytes=%d", tb->lbytes);
+       RFALSE(tb->pos_in_item != ih_item_len(item_head(tbS0, tb->item_pos)),
+              "PAP-12100: incorrect position to paste: "
+              "item_len=%d, pos_in_item=%d",
+              ih_item_len(item_head(tbS0, tb->item_pos)), tb->pos_in_item);
+
+       /* appended item will be in L[0] in whole */
+       if (tb->lbytes >= tb->pos_in_item) {
+               struct item_head *tbS0_pos_ih, *tbL0_ih;
+               struct item_head *tbS0_0_ih;
+               struct reiserfs_key *left_delim_key;
+               int ret, l_n, version, temp_l;
+
+               tbS0_pos_ih = item_head(tbS0, tb->item_pos);
+               tbS0_0_ih = item_head(tbS0, 0);
+
+               /*
+                * this bytes number must be appended
+                * to the last item of L[h]
+                */
+               l_n = tb->lbytes - tb->pos_in_item;
+
+               /* Calculate new insert_size[0] */
+               tb->insert_size[0] -= l_n;
+
+               RFALSE(tb->insert_size[0] <= 0,
+                      "PAP-12105: there is nothing to paste into "
+                      "L[0]. insert_size=%d", tb->insert_size[0]);
+
+               ret = leaf_shift_left(tb, tb->lnum[0],
+                                     ih_item_len(tbS0_pos_ih));
+
+               tbL0_ih = item_head(tb->L[0], n + tb->item_pos - ret);
+
+               /* Append to body of item in L[0] */
+               buffer_info_init_left(tb, &bi);
+               leaf_paste_in_buffer(&bi, n + tb->item_pos - ret,
+                                    ih_item_len(tbL0_ih), l_n, body,
+                                    min_t(int, l_n, tb->zeroes_num));
+
+               /*
+                * 0-th item in S0 can be only of DIRECT type
+                * when l_n != 0
+                */
+               temp_l = l_n;
+
+               RFALSE(ih_item_len(tbS0_0_ih),
+                      "PAP-12106: item length must be 0");
+               RFALSE(comp_short_le_keys(&tbS0_0_ih->ih_key,
+                      leaf_key(tb->L[0], n + tb->item_pos - ret)),
+                      "PAP-12107: items must be of the same file");
+
+               if (is_indirect_le_ih(tbL0_ih)) {
+                       int shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
+                       temp_l = l_n << shift;
+               }
+               /* update key of first item in S0 */
+               version = ih_version(tbS0_0_ih);
+               add_le_key_k_offset(version, &tbS0_0_ih->ih_key, temp_l);
+
+               /* update left delimiting key */
+               left_delim_key = internal_key(tb->CFL[0], tb->lkey[0]);
+               add_le_key_k_offset(version, left_delim_key, temp_l);
+
+               /*
+                * Calculate new body, position in item and
+                * insert_size[0]
+                */
+               if (l_n > tb->zeroes_num) {
+                       body_shift_bytes = l_n - tb->zeroes_num;
+                       tb->zeroes_num = 0;
+               } else
+                       tb->zeroes_num -= l_n;
+               tb->pos_in_item = 0;
+
+               RFALSE(comp_short_le_keys(&tbS0_0_ih->ih_key,
+                                         leaf_key(tb->L[0],
+                                                B_NR_ITEMS(tb->L[0]) - 1)) ||
+                      !op_is_left_mergeable(leaf_key(tbS0, 0), tbS0->b_size) ||
+                      !op_is_left_mergeable(left_delim_key, tbS0->b_size),
+                      "PAP-12120: item must be merge-able with left "
+                      "neighboring item");
+       } else {
+               /* only part of the appended item will be in L[0] */
+
+               /* Calculate position in item for append in S[0] */
+               tb->pos_in_item -= tb->lbytes;
+
+               RFALSE(tb->pos_in_item <= 0,
+                      "PAP-12125: no place for paste. pos_in_item=%d",
+                      tb->pos_in_item);
+
+               /*
+                * Shift lnum[0] - 1 items in whole.
+                * Shift lbytes - 1 byte from item number lnum[0]
+                */
+               leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
+       }
+       return body_shift_bytes;
+}
+
+
+/* appended item will be in L[0] in whole */
+static void balance_leaf_paste_left_whole(struct tree_balance *tb,
+                                         struct item_head * const ih,
+                                         const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tb->L[0]);
+       struct buffer_info bi;
+       struct item_head *pasted;
+       int ret;
+
+       /* if we paste into first item of S[0] and it is left mergable */
+       if (!tb->item_pos &&
+           op_is_left_mergeable(leaf_key(tbS0, 0), tbS0->b_size)) {
+               /*
+                * then increment pos_in_item by the size of the
+                * last item in L[0]
+                */
+               pasted = item_head(tb->L[0], n - 1);
+               if (is_direntry_le_ih(pasted))
+                       tb->pos_in_item += ih_entry_count(pasted);
+               else
+                       tb->pos_in_item += ih_item_len(pasted);
+       }
+
+       /*
+        * Shift lnum[0] - 1 items in whole.
+        * Shift lbytes - 1 byte from item number lnum[0]
+        */
+       ret = leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
+
+       /* Append to body of item in L[0] */
+       buffer_info_init_left(tb, &bi);
+       leaf_paste_in_buffer(&bi, n + tb->item_pos - ret, tb->pos_in_item,
+                            tb->insert_size[0], body, tb->zeroes_num);
+
+       /* if appended item is directory, paste entry */
+       pasted = item_head(tb->L[0], n + tb->item_pos - ret);
+       if (is_direntry_le_ih(pasted))
+               leaf_paste_entries(&bi, n + tb->item_pos - ret,
+                                  tb->pos_in_item, 1,
+                                  (struct reiserfs_de_head *)body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+
+       /*
+        * if appended item is indirect item, put unformatted node
+        * into un list
+        */
+       if (is_indirect_le_ih(pasted))
+               set_ih_free_space(pasted, 0);
+
+       tb->insert_size[0] = 0;
+       tb->zeroes_num = 0;
+}
+
+static unsigned int balance_leaf_paste_left(struct tree_balance *tb,
+                                           struct item_head * const ih,
+                                           const char * const body)
+{
+       /* we must shift the part of the appended item */
+       if (tb->item_pos == tb->lnum[0] - 1 && tb->lbytes != -1)
+               return balance_leaf_paste_left_shift(tb, ih, body);
+       else
+               balance_leaf_paste_left_whole(tb, ih, body);
+       return 0;
+}
+
+/* Shift lnum[0] items from S[0] to the left neighbor L[0] */
+static unsigned int balance_leaf_left(struct tree_balance *tb,
+                                     struct item_head * const ih,
+                                     const char * const body, int flag)
+{
+       if (tb->lnum[0] <= 0)
+               return 0;
+
+       /* new item or it part falls to L[0], shift it too */
+       if (tb->item_pos < tb->lnum[0]) {
+               BUG_ON(flag != M_INSERT && flag != M_PASTE);
+
+               if (flag == M_INSERT)
+                       return balance_leaf_insert_left(tb, ih, body);
+               else /* M_PASTE */
+                       return balance_leaf_paste_left(tb, ih, body);
+       } else
+               /* new item doesn't fall into L[0] */
+               leaf_shift_left(tb, tb->lnum[0], tb->lbytes);
+       return 0;
+}
+
+
+static void balance_leaf_insert_right(struct tree_balance *tb,
+                                     struct item_head * const ih,
+                                     const char * const body)
+{
+
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+       struct buffer_info bi;
+       int ret;
+
+       /* new item or part of it doesn't fall into R[0] */
+       if (n - tb->rnum[0] >= tb->item_pos) {
+               leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
+               return;
+       }
+
+       /* new item or its part falls to R[0] */
+
+       /* part of new item falls into R[0] */
+       if (tb->item_pos == n - tb->rnum[0] + 1 && tb->rbytes != -1) {
+               loff_t old_key_comp, old_len, r_zeroes_number;
+               const char *r_body;
+               int version, shift;
+               loff_t offset;
+
+               leaf_shift_right(tb, tb->rnum[0] - 1, -1);
+
+               version = ih_version(ih);
+
+               /* Remember key component and item length */
+               old_key_comp = le_ih_k_offset(ih);
+               old_len = ih_item_len(ih);
+
+               /*
+                * Calculate key component and item length to insert
+                * into R[0]
+                */
+               shift = 0;
+               if (is_indirect_le_ih(ih))
+                       shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
+               offset = le_ih_k_offset(ih) + ((old_len - tb->rbytes) << shift);
+               set_le_ih_k_offset(ih, offset);
+               put_ih_item_len(ih, tb->rbytes);
+
+               /* Insert part of the item into R[0] */
+               buffer_info_init_right(tb, &bi);
+               if ((old_len - tb->rbytes) > tb->zeroes_num) {
+                       r_zeroes_number = 0;
+                       r_body = body + (old_len - tb->rbytes) - tb->zeroes_num;
+               } else {
+                       r_body = body;
+                       r_zeroes_number = tb->zeroes_num -
+                                         (old_len - tb->rbytes);
+                       tb->zeroes_num -= r_zeroes_number;
+               }
+
+               leaf_insert_into_buf(&bi, 0, ih, r_body, r_zeroes_number);
+
+               /* Replace right delimiting key by first key in R[0] */
+               replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
+
+               /*
+                * Calculate key component and item length to
+                * insert into S[0]
+                */
+               set_le_ih_k_offset(ih, old_key_comp);
+               put_ih_item_len(ih, old_len - tb->rbytes);
+
+               tb->insert_size[0] -= tb->rbytes;
+
+       } else {
+               /* whole new item falls into R[0] */
+
+               /* Shift rnum[0]-1 items to R[0] */
+               ret = leaf_shift_right(tb, tb->rnum[0] - 1, tb->rbytes);
+
+               /* Insert new item into R[0] */
+               buffer_info_init_right(tb, &bi);
+               leaf_insert_into_buf(&bi, tb->item_pos - n + tb->rnum[0] - 1,
+                                    ih, body, tb->zeroes_num);
+
+               if (tb->item_pos - n + tb->rnum[0] - 1 == 0)
+                       replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
+
+               tb->zeroes_num = tb->insert_size[0] = 0;
+       }
+}
+
+
+static void balance_leaf_paste_right_shift_dirent(struct tree_balance *tb,
+                                    struct item_head * const ih,
+                                    const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       struct buffer_info bi;
+       int entry_count;
+
+       RFALSE(tb->zeroes_num,
+              "PAP-12145: invalid parameter in case of a directory");
+       entry_count = ih_entry_count(item_head(tbS0, tb->item_pos));
+
+       /* new directory entry falls into R[0] */
+       if (entry_count - tb->rbytes < tb->pos_in_item) {
+               int paste_entry_position;
+
+               RFALSE(tb->rbytes - 1 >= entry_count || !tb->insert_size[0],
+                      "PAP-12150: no enough of entries to shift to R[0]: "
+                      "rbytes=%d, entry_count=%d", tb->rbytes, entry_count);
+
+               /*
+                * Shift rnum[0]-1 items in whole.
+                * Shift rbytes-1 directory entries from directory
+                * item number rnum[0]
+                */
+               leaf_shift_right(tb, tb->rnum[0], tb->rbytes - 1);
+
+               /* Paste given directory entry to directory item */
+               paste_entry_position = tb->pos_in_item - entry_count +
+                                      tb->rbytes - 1;
+               buffer_info_init_right(tb, &bi);
+               leaf_paste_in_buffer(&bi, 0, paste_entry_position,
+                                    tb->insert_size[0], body, tb->zeroes_num);
+
+               /* paste entry */
+               leaf_paste_entries(&bi, 0, paste_entry_position, 1,
+                                  (struct reiserfs_de_head *) body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+
+               /* change delimiting keys */
+               if (paste_entry_position == 0)
+                       replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
+
+               tb->insert_size[0] = 0;
+               tb->pos_in_item++;
+       } else {
+               /* new directory entry doesn't fall into R[0] */
+               leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
+       }
+}
+
+static void balance_leaf_paste_right_shift(struct tree_balance *tb,
+                                    struct item_head * const ih,
+                                    const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n_shift, n_rem, r_zeroes_number, version;
+       unsigned long temp_rem;
+       const char *r_body;
+       struct buffer_info bi;
+
+       /* we append to directory item */
+       if (is_direntry_le_ih(item_head(tbS0, tb->item_pos))) {
+               balance_leaf_paste_right_shift_dirent(tb, ih, body);
+               return;
+       }
+
+       /* regular object */
+
+       /*
+        * Calculate number of bytes which must be shifted
+        * from appended item
+        */
+       n_shift = tb->rbytes - tb->insert_size[0];
+       if (n_shift < 0)
+               n_shift = 0;
+
+       RFALSE(tb->pos_in_item != ih_item_len(item_head(tbS0, tb->item_pos)),
+              "PAP-12155: invalid position to paste. ih_item_len=%d, "
+              "pos_in_item=%d", tb->pos_in_item,
+              ih_item_len(item_head(tbS0, tb->item_pos)));
+
+       leaf_shift_right(tb, tb->rnum[0], n_shift);
+
+       /*
+        * Calculate number of bytes which must remain in body
+        * after appending to R[0]
+        */
+       n_rem = tb->insert_size[0] - tb->rbytes;
+       if (n_rem < 0)
+               n_rem = 0;
+
+       temp_rem = n_rem;
+
+       version = ih_version(item_head(tb->R[0], 0));
+
+       if (is_indirect_le_key(version, leaf_key(tb->R[0], 0))) {
+               int shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
+               temp_rem = n_rem << shift;
+       }
+
+       add_le_key_k_offset(version, leaf_key(tb->R[0], 0), temp_rem);
+       add_le_key_k_offset(version, internal_key(tb->CFR[0], tb->rkey[0]),
+                           temp_rem);
+
+       do_balance_mark_internal_dirty(tb, tb->CFR[0], 0);
+
+       /* Append part of body into R[0] */
+       buffer_info_init_right(tb, &bi);
+       if (n_rem > tb->zeroes_num) {
+               r_zeroes_number = 0;
+               r_body = body + n_rem - tb->zeroes_num;
+       } else {
+               r_body = body;
+               r_zeroes_number = tb->zeroes_num - n_rem;
+               tb->zeroes_num -= r_zeroes_number;
+       }
+
+       leaf_paste_in_buffer(&bi, 0, n_shift, tb->insert_size[0] - n_rem,
+                            r_body, r_zeroes_number);
+
+       if (is_indirect_le_ih(item_head(tb->R[0], 0)))
+               set_ih_free_space(item_head(tb->R[0], 0), 0);
+
+       tb->insert_size[0] = n_rem;
+       if (!n_rem)
+               tb->pos_in_item++;
+}
+
+static void balance_leaf_paste_right_whole(struct tree_balance *tb,
+                                    struct item_head * const ih,
+                                    const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+       struct item_head *pasted;
+       struct buffer_info bi;
+
+                                                       buffer_info_init_right(tb, &bi);
+       leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
+
+       /* append item in R[0] */
+       if (tb->pos_in_item >= 0) {
+               buffer_info_init_right(tb, &bi);
+               leaf_paste_in_buffer(&bi, tb->item_pos - n + tb->rnum[0],
+                                    tb->pos_in_item, tb->insert_size[0], body,
+                                    tb->zeroes_num);
+       }
+
+       /* paste new entry, if item is directory item */
+       pasted = item_head(tb->R[0], tb->item_pos - n + tb->rnum[0]);
+       if (is_direntry_le_ih(pasted) && tb->pos_in_item >= 0) {
+               leaf_paste_entries(&bi, tb->item_pos - n + tb->rnum[0],
+                                  tb->pos_in_item, 1,
+                                  (struct reiserfs_de_head *)body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+
+               if (!tb->pos_in_item) {
+
+                       RFALSE(tb->item_pos - n + tb->rnum[0],
+                              "PAP-12165: directory item must be first "
+                              "item of node when pasting is in 0th position");
+
+                       /* update delimiting keys */
+                       replace_key(tb, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
+               }
+       }
+
+       if (is_indirect_le_ih(pasted))
+               set_ih_free_space(pasted, 0);
+       tb->zeroes_num = tb->insert_size[0] = 0;
+}
+
+static void balance_leaf_paste_right(struct tree_balance *tb,
+                                    struct item_head * const ih,
+                                    const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+
+       /* new item doesn't fall into R[0] */
+       if (n - tb->rnum[0] > tb->item_pos) {
+               leaf_shift_right(tb, tb->rnum[0], tb->rbytes);
+               return;
+       }
+
+       /* pasted item or part of it falls to R[0] */
+
+       if (tb->item_pos == n - tb->rnum[0] && tb->rbytes != -1)
+               /* we must shift the part of the appended item */
+               balance_leaf_paste_right_shift(tb, ih, body);
+       else
+               /* pasted item in whole falls into R[0] */
+               balance_leaf_paste_right_whole(tb, ih, body);
+}
+
+/* shift rnum[0] items from S[0] to the right neighbor R[0] */
+static void balance_leaf_right(struct tree_balance *tb,
+                              struct item_head * const ih,
+                              const char * const body, int flag)
+{
+       if (tb->rnum[0] <= 0)
+               return;
+
+       BUG_ON(flag != M_INSERT && flag != M_PASTE);
+
+       if (flag == M_INSERT)
+               balance_leaf_insert_right(tb, ih, body);
+       else /* M_PASTE */
+               balance_leaf_paste_right(tb, ih, body);
+}
+
+static void balance_leaf_new_nodes_insert(struct tree_balance *tb,
+                                         struct item_head * const ih,
+                                         const char * const body,
+                                         struct item_head *insert_key,
+                                         struct buffer_head **insert_ptr,
+                                         int i)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+       struct buffer_info bi;
+       int shift;
+
+       /* new item or it part don't falls into S_new[i] */
+       if (n - tb->snum[i] >= tb->item_pos) {
+               leaf_move_items(LEAF_FROM_S_TO_SNEW, tb,
+                               tb->snum[i], tb->sbytes[i], tb->S_new[i]);
+               return;
+       }
+
+       /* new item or it's part falls to first new node S_new[i] */
+
+       /* part of new item falls into S_new[i] */
+       if (tb->item_pos == n - tb->snum[i] + 1 && tb->sbytes[i] != -1) {
+               int old_key_comp, old_len, r_zeroes_number;
+               const char *r_body;
+               int version;
+
+               /* Move snum[i]-1 items from S[0] to S_new[i] */
+               leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i] - 1, -1,
+                               tb->S_new[i]);
+
+               /* Remember key component and item length */
+               version = ih_version(ih);
+               old_key_comp = le_ih_k_offset(ih);
+               old_len = ih_item_len(ih);
+
+               /*
+                * Calculate key component and item length to insert
+                * into S_new[i]
+                */
+               shift = 0;
+               if (is_indirect_le_ih(ih))
+                       shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
+               set_le_ih_k_offset(ih,
+                                  le_ih_k_offset(ih) +
+                                  ((old_len - tb->sbytes[i]) << shift));
+
+               put_ih_item_len(ih, tb->sbytes[i]);
+
+               /* Insert part of the item into S_new[i] before 0-th item */
+               buffer_info_init_bh(tb, &bi, tb->S_new[i]);
+
+               if ((old_len - tb->sbytes[i]) > tb->zeroes_num) {
+                       r_zeroes_number = 0;
+                       r_body = body + (old_len - tb->sbytes[i]) -
+                                        tb->zeroes_num;
+               } else {
+                       r_body = body;
+                       r_zeroes_number = tb->zeroes_num - (old_len -
+                                         tb->sbytes[i]);
+                       tb->zeroes_num -= r_zeroes_number;
+               }
+
+               leaf_insert_into_buf(&bi, 0, ih, r_body, r_zeroes_number);
+
+               /*
+                * Calculate key component and item length to
+                * insert into S[i]
+                */
+               set_le_ih_k_offset(ih, old_key_comp);
+               put_ih_item_len(ih, old_len - tb->sbytes[i]);
+               tb->insert_size[0] -= tb->sbytes[i];
+       } else {
+               /* whole new item falls into S_new[i] */
+
+               /*
+                * Shift snum[0] - 1 items to S_new[i]
+                * (sbytes[i] of split item)
+                */
+               leaf_move_items(LEAF_FROM_S_TO_SNEW, tb,
+                               tb->snum[i] - 1, tb->sbytes[i], tb->S_new[i]);
+
+               /* Insert new item into S_new[i] */
+               buffer_info_init_bh(tb, &bi, tb->S_new[i]);
+               leaf_insert_into_buf(&bi, tb->item_pos - n + tb->snum[i] - 1,
+                                    ih, body, tb->zeroes_num);
+
+               tb->zeroes_num = tb->insert_size[0] = 0;
+       }
+}
+
+/* we append to directory item */
+static void balance_leaf_new_nodes_paste_dirent(struct tree_balance *tb,
+                                        struct item_head * const ih,
+                                        const char * const body,
+                                        struct item_head *insert_key,
+                                        struct buffer_head **insert_ptr,
+                                        int i)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       struct item_head *aux_ih = item_head(tbS0, tb->item_pos);
+       int entry_count = ih_entry_count(aux_ih);
+       struct buffer_info bi;
+
+       if (entry_count - tb->sbytes[i] < tb->pos_in_item &&
+           tb->pos_in_item <= entry_count) {
+               /* new directory entry falls into S_new[i] */
+
+               RFALSE(!tb->insert_size[0],
+                      "PAP-12215: insert_size is already 0");
+               RFALSE(tb->sbytes[i] - 1 >= entry_count,
+                      "PAP-12220: there are no so much entries (%d), only %d",
+                      tb->sbytes[i] - 1, entry_count);
+
+               /*
+                * Shift snum[i]-1 items in whole.
+                * Shift sbytes[i] directory entries
+                * from directory item number snum[i]
+                */
+               leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i],
+                               tb->sbytes[i] - 1, tb->S_new[i]);
+
+               /*
+                * Paste given directory entry to
+                * directory item
+                */
+               buffer_info_init_bh(tb, &bi, tb->S_new[i]);
+               leaf_paste_in_buffer(&bi, 0, tb->pos_in_item - entry_count +
+                                    tb->sbytes[i] - 1, tb->insert_size[0],
+                                    body, tb->zeroes_num);
+
+               /* paste new directory entry */
+               leaf_paste_entries(&bi, 0, tb->pos_in_item - entry_count +
+                                  tb->sbytes[i] - 1, 1,
+                                  (struct reiserfs_de_head *) body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+
+               tb->insert_size[0] = 0;
+               tb->pos_in_item++;
+       } else {
+               /* new directory entry doesn't fall into S_new[i] */
+               leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i],
+                               tb->sbytes[i], tb->S_new[i]);
+       }
+
+}
+
+static void balance_leaf_new_nodes_paste_shift(struct tree_balance *tb,
+                                        struct item_head * const ih,
+                                        const char * const body,
+                                        struct item_head *insert_key,
+                                        struct buffer_head **insert_ptr,
+                                        int i)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       struct item_head *aux_ih = item_head(tbS0, tb->item_pos);
+       int n_shift, n_rem, r_zeroes_number, shift;
+       const char *r_body;
+       struct item_head *tmp;
+       struct buffer_info bi;
+
+       RFALSE(ih, "PAP-12210: ih must be 0");
+
+       if (is_direntry_le_ih(aux_ih)) {
+               balance_leaf_new_nodes_paste_dirent(tb, ih, body, insert_key,
+                                                   insert_ptr, i);
+               return;
+       }
+
+       /* regular object */
+
+
+       RFALSE(tb->pos_in_item != ih_item_len(item_head(tbS0, tb->item_pos)) ||
+              tb->insert_size[0] <= 0,
+              "PAP-12225: item too short or insert_size <= 0");
+
+       /*
+        * Calculate number of bytes which must be shifted from appended item
+        */
+       n_shift = tb->sbytes[i] - tb->insert_size[0];
+       if (n_shift < 0)
+               n_shift = 0;
+       leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i], n_shift,
+                       tb->S_new[i]);
+
+       /*
+        * Calculate number of bytes which must remain in body after
+        * append to S_new[i]
+        */
+       n_rem = tb->insert_size[0] - tb->sbytes[i];
+       if (n_rem < 0)
+               n_rem = 0;
+
+       /* Append part of body into S_new[0] */
+       buffer_info_init_bh(tb, &bi, tb->S_new[i]);
+       if (n_rem > tb->zeroes_num) {
+               r_zeroes_number = 0;
+               r_body = body + n_rem - tb->zeroes_num;
+       } else {
+               r_body = body;
+               r_zeroes_number = tb->zeroes_num - n_rem;
+               tb->zeroes_num -= r_zeroes_number;
+       }
+
+       leaf_paste_in_buffer(&bi, 0, n_shift, tb->insert_size[0] - n_rem,
+                            r_body, r_zeroes_number);
+
+       tmp = item_head(tb->S_new[i], 0);
+       shift = 0;
+       if (is_indirect_le_ih(tmp)) {
+               set_ih_free_space(tmp, 0);
+               shift = tb->tb_sb->s_blocksize_bits - UNFM_P_SHIFT;
+       }
+       add_le_ih_k_offset(tmp, n_rem << shift);
+
+       tb->insert_size[0] = n_rem;
+       if (!n_rem)
+               tb->pos_in_item++;
+}
+
+static void balance_leaf_new_nodes_paste_whole(struct tree_balance *tb,
+                                              struct item_head * const ih,
+                                              const char * const body,
+                                              struct item_head *insert_key,
+                                              struct buffer_head **insert_ptr,
+                                              int i)
+
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+       int leaf_mi;
+       struct item_head *pasted;
+       struct buffer_info bi;
+
+#ifdef CONFIG_REISERFS_CHECK
+       struct item_head *ih_check = item_head(tbS0, tb->item_pos);
+
+       if (!is_direntry_le_ih(ih_check) &&
+           (tb->pos_in_item != ih_item_len(ih_check) ||
+           tb->insert_size[0] <= 0))
+               reiserfs_panic(tb->tb_sb,
+                            "PAP-12235",
+                            "pos_in_item must be equal to ih_item_len");
+#endif
+
+       leaf_mi = leaf_move_items(LEAF_FROM_S_TO_SNEW, tb, tb->snum[i],
+                                 tb->sbytes[i], tb->S_new[i]);
+
+       RFALSE(leaf_mi,
+              "PAP-12240: unexpected value returned by leaf_move_items (%d)",
+              leaf_mi);
+
+       /* paste into item */
+       buffer_info_init_bh(tb, &bi, tb->S_new[i]);
+       leaf_paste_in_buffer(&bi, tb->item_pos - n + tb->snum[i],
+                            tb->pos_in_item, tb->insert_size[0],
+                            body, tb->zeroes_num);
+
+       pasted = item_head(tb->S_new[i], tb->item_pos - n +
+                          tb->snum[i]);
+       if (is_direntry_le_ih(pasted))
+               leaf_paste_entries(&bi, tb->item_pos - n + tb->snum[i],
+                                  tb->pos_in_item, 1,
+                                  (struct reiserfs_de_head *)body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+
+       /* if we paste to indirect item update ih_free_space */
+       if (is_indirect_le_ih(pasted))
+               set_ih_free_space(pasted, 0);
+
+       tb->zeroes_num = tb->insert_size[0] = 0;
+
+}
+static void balance_leaf_new_nodes_paste(struct tree_balance *tb,
+                                        struct item_head * const ih,
+                                        const char * const body,
+                                        struct item_head *insert_key,
+                                        struct buffer_head **insert_ptr,
+                                        int i)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       int n = B_NR_ITEMS(tbS0);
+
+       /* pasted item doesn't fall into S_new[i] */
+       if (n - tb->snum[i] > tb->item_pos) {
+               leaf_move_items(LEAF_FROM_S_TO_SNEW, tb,
+                               tb->snum[i], tb->sbytes[i], tb->S_new[i]);
+               return;
+       }
+
+       /* pasted item or part if it falls to S_new[i] */
+
+       if (tb->item_pos == n - tb->snum[i] && tb->sbytes[i] != -1)
+               /* we must shift part of the appended item */
+               balance_leaf_new_nodes_paste_shift(tb, ih, body, insert_key,
+                                                  insert_ptr, i);
+       else
+               /* item falls wholly into S_new[i] */
+               balance_leaf_new_nodes_paste_whole(tb, ih, body, insert_key,
+                                                  insert_ptr, i);
+}
+
+/* Fill new nodes that appear in place of S[0] */
+static void balance_leaf_new_nodes(struct tree_balance *tb,
+                                  struct item_head * const ih,
+                                  const char * const body,
+                                  struct item_head *insert_key,
+                                  struct buffer_head **insert_ptr,
+                                  int flag)
+{
+       int i;
+       for (i = tb->blknum[0] - 2; i >= 0; i--) {
+               BUG_ON(flag != M_INSERT && flag != M_PASTE);
+
+               RFALSE(!tb->snum[i],
+                      "PAP-12200: snum[%d] == %d. Must be > 0", i,
+                      tb->snum[i]);
+
+               /* here we shift from S to S_new nodes */
+
+               tb->S_new[i] = get_FEB(tb);
+
+               /* initialized block type and tree level */
+               set_blkh_level(B_BLK_HEAD(tb->S_new[i]), DISK_LEAF_NODE_LEVEL);
+
+               if (flag == M_INSERT)
+                       balance_leaf_new_nodes_insert(tb, ih, body, insert_key,
+                                                     insert_ptr, i);
+               else /* M_PASTE */
+                       balance_leaf_new_nodes_paste(tb, ih, body, insert_key,
+                                                    insert_ptr, i);
+
+               memcpy(insert_key + i, leaf_key(tb->S_new[i], 0), KEY_SIZE);
+               insert_ptr[i] = tb->S_new[i];
+
+               RFALSE(!buffer_journaled(tb->S_new[i])
+                      || buffer_journal_dirty(tb->S_new[i])
+                      || buffer_dirty(tb->S_new[i]),
+                      "PAP-12247: S_new[%d] : (%b)",
+                      i, tb->S_new[i]);
+       }
+}
+
+static void balance_leaf_finish_node_insert(struct tree_balance *tb,
+                                           struct item_head * const ih,
+                                           const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       struct buffer_info bi;
+       buffer_info_init_tbS0(tb, &bi);
+       leaf_insert_into_buf(&bi, tb->item_pos, ih, body, tb->zeroes_num);
+
+       /* If we insert the first key change the delimiting key */
+       if (tb->item_pos == 0) {
+               if (tb->CFL[0]) /* can be 0 in reiserfsck */
+                       replace_key(tb, tb->CFL[0], tb->lkey[0], tbS0, 0);
+
+       }
+}
+
+static void balance_leaf_finish_node_paste_dirent(struct tree_balance *tb,
+                                                 struct item_head * const ih,
+                                                 const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       struct item_head *pasted = item_head(tbS0, tb->item_pos);
+       struct buffer_info bi;
+
+       if (tb->pos_in_item >= 0 && tb->pos_in_item <= ih_entry_count(pasted)) {
+               RFALSE(!tb->insert_size[0],
+                      "PAP-12260: insert_size is 0 already");
+
+               /* prepare space */
+               buffer_info_init_tbS0(tb, &bi);
+               leaf_paste_in_buffer(&bi, tb->item_pos, tb->pos_in_item,
+                                    tb->insert_size[0], body, tb->zeroes_num);
+
+               /* paste entry */
+               leaf_paste_entries(&bi, tb->item_pos, tb->pos_in_item, 1,
+                                  (struct reiserfs_de_head *)body,
+                                  body + DEH_SIZE, tb->insert_size[0]);
+
+               if (!tb->item_pos && !tb->pos_in_item) {
+                       RFALSE(!tb->CFL[0] || !tb->L[0],
+                              "PAP-12270: CFL[0]/L[0] must  be specified");
+                       if (tb->CFL[0])
+                               replace_key(tb, tb->CFL[0], tb->lkey[0],
+                                           tbS0, 0);
+               }
+
+               tb->insert_size[0] = 0;
+       }
+}
+
+static void balance_leaf_finish_node_paste(struct tree_balance *tb,
+                                          struct item_head * const ih,
+                                          const char * const body)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+       struct buffer_info bi;
+       struct item_head *pasted = item_head(tbS0, tb->item_pos);
+
+       /* when directory, may be new entry already pasted */
+       if (is_direntry_le_ih(pasted)) {
+               balance_leaf_finish_node_paste_dirent(tb, ih, body);
+               return;
+       }
+
+       /* regular object */
+
+       if (tb->pos_in_item == ih_item_len(pasted)) {
+               RFALSE(tb->insert_size[0] <= 0,
+                      "PAP-12275: insert size must not be %d",
+                      tb->insert_size[0]);
+               buffer_info_init_tbS0(tb, &bi);
+               leaf_paste_in_buffer(&bi, tb->item_pos,
+                                    tb->pos_in_item, tb->insert_size[0], body,
+                                    tb->zeroes_num);
+
+               if (is_indirect_le_ih(pasted))
+                       set_ih_free_space(pasted, 0);
+
+               tb->insert_size[0] = 0;
+       }
+#ifdef CONFIG_REISERFS_CHECK
+       else if (tb->insert_size[0]) {
+               print_cur_tb("12285");
+               reiserfs_panic(tb->tb_sb, "PAP-12285",
+                   "insert_size must be 0 (%d)", tb->insert_size[0]);
+       }
+#endif
+}
+
+/*
+ * if the affected item was not wholly shifted then we
+ * perform all necessary operations on that part or whole
+ * of the affected item which remains in S
+ */
+static void balance_leaf_finish_node(struct tree_balance *tb,
+                                     struct item_head * const ih,
+                                     const char * const body, int flag)
+{
+       /* if we must insert or append into buffer S[0] */
+       if (0 <= tb->item_pos && tb->item_pos < tb->s0num) {
+               if (flag == M_INSERT)
+                       balance_leaf_finish_node_insert(tb, ih, body);
+               else /* M_PASTE */
+                       balance_leaf_finish_node_paste(tb, ih, body);
+       }
+}
+
+/**
+ * balance_leaf - reiserfs tree balancing algorithm
+ * @tb: tree balance state
+ * @ih: item header of inserted item (little endian)
+ * @body: body of inserted item or bytes to paste
+ * @flag: i - insert, d - delete, c - cut, p - paste (see do_balance)
+ * passed back:
+ * @insert_key: key to insert new nodes
+ * @insert_ptr: array of nodes to insert at the next level
+ *
+ * In our processing of one level we sometimes determine what must be
+ * inserted into the next higher level.  This insertion consists of a
+ * key or two keys and their corresponding pointers.
+ */
+static int balance_leaf(struct tree_balance *tb, struct item_head *ih,
+                       const char *body, int flag,
+                       struct item_head *insert_key,
+                       struct buffer_head **insert_ptr)
+{
+       struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path);
+
+       PROC_INFO_INC(tb->tb_sb, balance_at[0]);
+
+       /* Make balance in case insert_size[0] < 0 */
+       if (tb->insert_size[0] < 0)
+               return balance_leaf_when_delete(tb, flag);
+
+       tb->item_pos = PATH_LAST_POSITION(tb->tb_path),
+       tb->pos_in_item = tb->tb_path->pos_in_item,
+       tb->zeroes_num = 0;
+       if (flag == M_INSERT && !body)
+               tb->zeroes_num = ih_item_len(ih);
+
+       /*
+        * for indirect item pos_in_item is measured in unformatted node
+        * pointers. Recalculate to bytes
+        */
+       if (flag != M_INSERT
+           && is_indirect_le_ih(item_head(tbS0, tb->item_pos)))
+               tb->pos_in_item *= UNFM_P_SIZE;
+
+       body += balance_leaf_left(tb, ih, body, flag);
+
+       /* tb->lnum[0] > 0 */
+       /* Calculate new item position */
+       tb->item_pos -= (tb->lnum[0] - ((tb->lbytes != -1) ? 1 : 0));
+
+       balance_leaf_right(tb, ih, body, flag);
+
+       /* tb->rnum[0] > 0 */
+       RFALSE(tb->blknum[0] > 3,
+              "PAP-12180: blknum can not be %d. It must be <= 3", tb->blknum[0]);
+       RFALSE(tb->blknum[0] < 0,
+              "PAP-12185: blknum can not be %d. It must be >= 0", tb->blknum[0]);
+
+       /*
+        * if while adding to a node we discover that it is possible to split
+        * it in two, and merge the left part into the left neighbor and the
+        * right part into the right neighbor, eliminating the node
+        */
+       if (tb->blknum[0] == 0) {       /* node S[0] is empty now */
+
+               RFALSE(!tb->lnum[0] || !tb->rnum[0],
+                      "PAP-12190: lnum and rnum must not be zero");
+               /*
+                * if insertion was done before 0-th position in R[0], right
+                * delimiting key of the tb->L[0]'s and left delimiting key are
+                * not set correctly
+                */
+               if (tb->CFL[0]) {
+                       if (!tb->CFR[0])
+                               reiserfs_panic(tb->tb_sb, "vs-12195",
+                                              "CFR not initialized");
+                       copy_key(internal_key(tb->CFL[0], tb->lkey[0]),
+                                internal_key(tb->CFR[0], tb->rkey[0]));
+                       do_balance_mark_internal_dirty(tb, tb->CFL[0], 0);
+               }
+
+               reiserfs_invalidate_buffer(tb, tbS0);
+               return 0;
+       }
+
+       balance_leaf_new_nodes(tb, ih, body, insert_key, insert_ptr, flag);
+
+       balance_leaf_finish_node(tb, ih, body, flag);
+
+#ifdef CONFIG_REISERFS_CHECK
+       if (flag == M_PASTE && tb->insert_size[0]) {
+               print_cur_tb("12290");
+               reiserfs_panic(tb->tb_sb,
+                              "PAP-12290", "insert_size is still not 0 (%d)",
+                              tb->insert_size[0]);
+       }
+#endif
+
+       /* Leaf level of the tree is balanced (end of balance_leaf) */
+       return 0;
+}
+
+/* Make empty node */
+void make_empty_node(struct buffer_info *bi)
+{
+       struct block_head *blkh;
+
+       RFALSE(bi->bi_bh == NULL, "PAP-12295: pointer to the buffer is NULL");
+
+       blkh = B_BLK_HEAD(bi->bi_bh);
+       set_blkh_nr_item(blkh, 0);
+       set_blkh_free_space(blkh, MAX_CHILD_SIZE(bi->bi_bh));
+
+       if (bi->bi_parent)
+               B_N_CHILD(bi->bi_parent, bi->bi_position)->dc_size = 0; /* Endian safe if 0 */
+}
+
+/* Get first empty buffer */
+struct buffer_head *get_FEB(struct tree_balance *tb)
+{
+       int i;
+       struct buffer_info bi;
+
+       for (i = 0; i < MAX_FEB_SIZE; i++)
+               if (tb->FEB[i] != NULL)
+                       break;
+
+       if (i == MAX_FEB_SIZE)
+               reiserfs_panic(tb->tb_sb, "vs-12300", "FEB list is empty");
+
+       buffer_info_init_bh(tb, &bi, tb->FEB[i]);
+       make_empty_node(&bi);
+       set_buffer_uptodate(tb->FEB[i]);
+       tb->used[i] = tb->FEB[i];
+       tb->FEB[i] = NULL;
+
+       return tb->used[i];
+}
+
+/* This is now used because reiserfs_free_block has to be able to schedule. */
+static void store_thrown(struct tree_balance *tb, struct buffer_head *bh)
+{
+       int i;
+
+       if (buffer_dirty(bh))
+               reiserfs_warning(tb->tb_sb, "reiserfs-12320",
+                                "called with dirty buffer");
+       for (i = 0; i < ARRAY_SIZE(tb->thrown); i++)
+               if (!tb->thrown[i]) {
+                       tb->thrown[i] = bh;
+                       get_bh(bh);     /* free_thrown puts this */
+                       return;
+               }
+       reiserfs_warning(tb->tb_sb, "reiserfs-12321",
+                        "too many thrown buffers");
+}
+
+static void free_thrown(struct tree_balance *tb)
+{
+       int i;
+       b_blocknr_t blocknr;
+       for (i = 0; i < ARRAY_SIZE(tb->thrown); i++) {
+               if (tb->thrown[i]) {
+                       blocknr = tb->thrown[i]->b_blocknr;
+                       if (buffer_dirty(tb->thrown[i]))
+                               reiserfs_warning(tb->tb_sb, "reiserfs-12322",
+                                                "called with dirty buffer %d",
+                                                blocknr);
+                       brelse(tb->thrown[i]);  /* incremented in store_thrown */
+                       reiserfs_free_block(tb->transaction_handle, NULL,
+                                           blocknr, 0);
+               }
+       }
+}
+
+void reiserfs_invalidate_buffer(struct tree_balance *tb, struct buffer_head *bh)
+{
+       struct block_head *blkh;
+       blkh = B_BLK_HEAD(bh);
+       set_blkh_level(blkh, FREE_LEVEL);
+       set_blkh_nr_item(blkh, 0);
+
+       clear_buffer_dirty(bh);
+       store_thrown(tb, bh);
+}
+
+/* Replace n_dest'th key in buffer dest by n_src'th key of buffer src.*/
+void replace_key(struct tree_balance *tb, struct buffer_head *dest, int n_dest,
+                struct buffer_head *src, int n_src)
+{
+
+       RFALSE(dest == NULL || src == NULL,
+              "vs-12305: source or destination buffer is 0 (src=%p, dest=%p)",
+              src, dest);
+       RFALSE(!B_IS_KEYS_LEVEL(dest),
+              "vs-12310: invalid level (%z) for destination buffer. dest must be leaf",
+              dest);
+       RFALSE(n_dest < 0 || n_src < 0,
+              "vs-12315: src(%d) or dest(%d) key number < 0", n_src, n_dest);
+       RFALSE(n_dest >= B_NR_ITEMS(dest) || n_src >= B_NR_ITEMS(src),
+              "vs-12320: src(%d(%d)) or dest(%d(%d)) key number is too big",
+              n_src, B_NR_ITEMS(src), n_dest, B_NR_ITEMS(dest));
+
+       if (B_IS_ITEMS_LEVEL(src))
+               /* source buffer contains leaf node */
+               memcpy(internal_key(dest, n_dest), item_head(src, n_src),
+                      KEY_SIZE);
+       else
+               memcpy(internal_key(dest, n_dest), internal_key(src, n_src),
+                      KEY_SIZE);
+
+       do_balance_mark_internal_dirty(tb, dest, 0);
+}
+
+int get_left_neighbor_position(struct tree_balance *tb, int h)
+{
+       int Sh_position = PATH_H_POSITION(tb->tb_path, h + 1);
+
+       RFALSE(PATH_H_PPARENT(tb->tb_path, h) == NULL || tb->FL[h] == NULL,
+              "vs-12325: FL[%d](%p) or F[%d](%p) does not exist",
+              h, tb->FL[h], h, PATH_H_PPARENT(tb->tb_path, h));
+
+       if (Sh_position == 0)
+               return B_NR_ITEMS(tb->FL[h]);
+       else
+               return Sh_position - 1;
+}
+
+int get_right_neighbor_position(struct tree_balance *tb, int h)
+{
+       int Sh_position = PATH_H_POSITION(tb->tb_path, h + 1);
+
+       RFALSE(PATH_H_PPARENT(tb->tb_path, h) == NULL || tb->FR[h] == NULL,
+              "vs-12330: F[%d](%p) or FR[%d](%p) does not exist",
+              h, PATH_H_PPARENT(tb->tb_path, h), h, tb->FR[h]);
+
+       if (Sh_position == B_NR_ITEMS(PATH_H_PPARENT(tb->tb_path, h)))
+               return 0;
+       else
+               return Sh_position + 1;
+}
+
+#ifdef CONFIG_REISERFS_CHECK
+
+int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value);
+static void check_internal_node(struct super_block *s, struct buffer_head *bh,
+                               char *mes)
+{
+       struct disk_child *dc;
+       int i;
+
+       RFALSE(!bh, "PAP-12336: bh == 0");
+
+       if (!bh || !B_IS_IN_TREE(bh))
+               return;
+
+       RFALSE(!buffer_dirty(bh) &&
+              !(buffer_journaled(bh) || buffer_journal_dirty(bh)),
+              "PAP-12337: buffer (%b) must be dirty", bh);
+       dc = B_N_CHILD(bh, 0);
+
+       for (i = 0; i <= B_NR_ITEMS(bh); i++, dc++) {
+               if (!is_reusable(s, dc_block_number(dc), 1)) {
+                       print_cur_tb(mes);
+                       reiserfs_panic(s, "PAP-12338",
+                                      "invalid child pointer %y in %b",
+                                      dc, bh);
+               }
+       }
+}
+
+static int locked_or_not_in_tree(struct tree_balance *tb,
+                                 struct buffer_head *bh, char *which)
+{
+       if ((!buffer_journal_prepared(bh) && buffer_locked(bh)) ||
+           !B_IS_IN_TREE(bh)) {
+               reiserfs_warning(tb->tb_sb, "vs-12339", "%s (%b)", which, bh);
+               return 1;
+       }
+       return 0;
+}
+
+static int check_before_balancing(struct tree_balance *tb)
+{
+       int retval = 0;
+
+       if (REISERFS_SB(tb->tb_sb)->cur_tb) {
+               reiserfs_panic(tb->tb_sb, "vs-12335", "suspect that schedule "
+                              "occurred based on cur_tb not being null at "
+                              "this point in code. do_balance cannot properly "
+                              "handle concurrent tree accesses on a same "
+                              "mount point.");
+       }
+
+       /*
+        * double check that buffers that we will modify are unlocked.
+        * (fix_nodes should already have prepped all of these for us).
+        */
+       if (tb->lnum[0]) {
+               retval |= locked_or_not_in_tree(tb, tb->L[0], "L[0]");
+               retval |= locked_or_not_in_tree(tb, tb->FL[0], "FL[0]");
+               retval |= locked_or_not_in_tree(tb, tb->CFL[0], "CFL[0]");
+               check_leaf(tb->L[0]);
+       }
+       if (tb->rnum[0]) {
+               retval |= locked_or_not_in_tree(tb, tb->R[0], "R[0]");
+               retval |= locked_or_not_in_tree(tb, tb->FR[0], "FR[0]");
+               retval |= locked_or_not_in_tree(tb, tb->CFR[0], "CFR[0]");
+               check_leaf(tb->R[0]);
+       }
+       retval |= locked_or_not_in_tree(tb, PATH_PLAST_BUFFER(tb->tb_path),
+                                       "S[0]");
+       check_leaf(PATH_PLAST_BUFFER(tb->tb_path));
+
+       return retval;
+}
+
+static void check_after_balance_leaf(struct tree_balance *tb)
+{
+       if (tb->lnum[0]) {
+               if (B_FREE_SPACE(tb->L[0]) !=
+                   MAX_CHILD_SIZE(tb->L[0]) -
+                   dc_size(B_N_CHILD
+                           (tb->FL[0], get_left_neighbor_position(tb, 0)))) {
+                       print_cur_tb("12221");
+                       reiserfs_panic(tb->tb_sb, "PAP-12355",
+                                      "shift to left was incorrect");
+               }
+       }
+       if (tb->rnum[0]) {
+               if (B_FREE_SPACE(tb->R[0]) !=
+                   MAX_CHILD_SIZE(tb->R[0]) -
+                   dc_size(B_N_CHILD
+                           (tb->FR[0], get_right_neighbor_position(tb, 0)))) {
+                       print_cur_tb("12222");
+                       reiserfs_panic(tb->tb_sb, "PAP-12360",
+                                      "shift to right was incorrect");
+               }
+       }
+       if (PATH_H_PBUFFER(tb->tb_path, 1) &&
+           (B_FREE_SPACE(PATH_H_PBUFFER(tb->tb_path, 0)) !=
+            (MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, 0)) -
+             dc_size(B_N_CHILD(PATH_H_PBUFFER(tb->tb_path, 1),
+                               PATH_H_POSITION(tb->tb_path, 1)))))) {
+               int left = B_FREE_SPACE(PATH_H_PBUFFER(tb->tb_path, 0));
+               int right = (MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, 0)) -
+                            dc_size(B_N_CHILD(PATH_H_PBUFFER(tb->tb_path, 1),
+                                              PATH_H_POSITION(tb->tb_path,
+                                                              1))));
+               print_cur_tb("12223");
+               reiserfs_warning(tb->tb_sb, "reiserfs-12363",
+                                "B_FREE_SPACE (PATH_H_PBUFFER(tb->tb_path,0)) = %d; "
+                                "MAX_CHILD_SIZE (%d) - dc_size( %y, %d ) [%d] = %d",
+                                left,
+                                MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, 0)),
+                                PATH_H_PBUFFER(tb->tb_path, 1),
+                                PATH_H_POSITION(tb->tb_path, 1),
+                                dc_size(B_N_CHILD
+                                        (PATH_H_PBUFFER(tb->tb_path, 1),
+                                         PATH_H_POSITION(tb->tb_path, 1))),
+                                right);
+               reiserfs_panic(tb->tb_sb, "PAP-12365", "S is incorrect");
+       }
+}
+
+static void check_leaf_level(struct tree_balance *tb)
+{
+       check_leaf(tb->L[0]);
+       check_leaf(tb->R[0]);
+       check_leaf(PATH_PLAST_BUFFER(tb->tb_path));
+}
+
+static void check_internal_levels(struct tree_balance *tb)
+{
+       int h;
+
+       /* check all internal nodes */
+       for (h = 1; tb->insert_size[h]; h++) {
+               check_internal_node(tb->tb_sb, PATH_H_PBUFFER(tb->tb_path, h),
+                                   "BAD BUFFER ON PATH");
+               if (tb->lnum[h])
+                       check_internal_node(tb->tb_sb, tb->L[h], "BAD L");
+               if (tb->rnum[h])
+                       check_internal_node(tb->tb_sb, tb->R[h], "BAD R");
+       }
+
+}
+
+#endif
+
+/*
+ * Now we have all of the buffers that must be used in balancing of
+ * the tree.  We rely on the assumption that schedule() will not occur
+ * while do_balance works. ( Only interrupt handlers are acceptable.)
+ * We balance the tree according to the analysis made before this,
+ * using buffers already obtained.  For SMP support it will someday be
+ * necessary to add ordered locking of tb.
+ */
+
+/*
+ * Some interesting rules of balancing:
+ * we delete a maximum of two nodes per level per balancing: we never
+ * delete R, when we delete two of three nodes L, S, R then we move
+ * them into R.
+ *
+ * we only delete L if we are deleting two nodes, if we delete only
+ * one node we delete S
+ *
+ * if we shift leaves then we shift as much as we can: this is a
+ * deliberate policy of extremism in node packing which results in
+ * higher average utilization after repeated random balance operations
+ * at the cost of more memory copies and more balancing as a result of
+ * small insertions to full nodes.
+ *
+ * if we shift internal nodes we try to evenly balance the node
+ * utilization, with consequent less balancing at the cost of lower
+ * utilization.
+ *
+ * one could argue that the policy for directories in leaves should be
+ * that of internal nodes, but we will wait until another day to
+ * evaluate this....  It would be nice to someday measure and prove
+ * these assumptions as to what is optimal....
+ */
+
+static inline void do_balance_starts(struct tree_balance *tb)
+{
+       /* use print_cur_tb() to see initial state of struct tree_balance */
+
+       /* store_print_tb (tb); */
+
+       /* do not delete, just comment it out */
+       /*
+       print_tb(flag, PATH_LAST_POSITION(tb->tb_path),
+                tb->tb_path->pos_in_item, tb, "check");
+       */
+       RFALSE(check_before_balancing(tb), "PAP-12340: locked buffers in TB");
+#ifdef CONFIG_REISERFS_CHECK
+       REISERFS_SB(tb->tb_sb)->cur_tb = tb;
+#endif
+}
+
+static inline void do_balance_completed(struct tree_balance *tb)
+{
+
+#ifdef CONFIG_REISERFS_CHECK
+       check_leaf_level(tb);
+       check_internal_levels(tb);
+       REISERFS_SB(tb->tb_sb)->cur_tb = NULL;
+#endif
+
+       /*
+        * reiserfs_free_block is no longer schedule safe.  So, we need to
+        * put the buffers we want freed on the thrown list during do_balance,
+        * and then free them now
+        */
+
+       REISERFS_SB(tb->tb_sb)->s_do_balance++;
+
+       /* release all nodes hold to perform the balancing */
+       unfix_nodes(tb);
+
+       free_thrown(tb);
+}
+
+/*
+ * do_balance - balance the tree
+ *
+ * @tb: tree_balance structure
+ * @ih: item header of inserted item
+ * @body: body of inserted item or bytes to paste
+ * @flag: 'i' - insert, 'd' - delete, 'c' - cut, 'p' paste
+ *
+ * Cut means delete part of an item (includes removing an entry from a
+ * directory).
+ *
+ * Delete means delete whole item.
+ *
+ * Insert means add a new item into the tree.
+ *
+ * Paste means to append to the end of an existing file or to
+ * insert a directory entry.
+ */
+void do_balance(struct tree_balance *tb, struct item_head *ih,
+               const char *body, int flag)
+{
+       int child_pos;          /* position of a child node in its parent */
+       int h;                  /* level of the tree being processed */
+
+       /*
+        * in our processing of one level we sometimes determine what
+        * must be inserted into the next higher level.  This insertion
+        * consists of a key or two keys and their corresponding
+        * pointers
+        */
+       struct item_head insert_key[2];
+
+       /* inserted node-ptrs for the next level */
+       struct buffer_head *insert_ptr[2];
+
+       tb->tb_mode = flag;
+       tb->need_balance_dirty = 0;
+
+       if (FILESYSTEM_CHANGED_TB(tb)) {
+               reiserfs_panic(tb->tb_sb, "clm-6000", "fs generation has "
+                              "changed");
+       }
+       /* if we have no real work to do  */
+       if (!tb->insert_size[0]) {
+               reiserfs_warning(tb->tb_sb, "PAP-12350",
+                                "insert_size == 0, mode == %c", flag);
+               unfix_nodes(tb);
+               return;
+       }
+
+       atomic_inc(&fs_generation(tb->tb_sb));
+       do_balance_starts(tb);
+
+       /*
+        * balance_leaf returns 0 except if combining L R and S into
+        * one node.  see balance_internal() for explanation of this
+        * line of code.
+        */
+       child_pos = PATH_H_B_ITEM_ORDER(tb->tb_path, 0) +
+           balance_leaf(tb, ih, body, flag, insert_key, insert_ptr);
+
+#ifdef CONFIG_REISERFS_CHECK
+       check_after_balance_leaf(tb);
+#endif
+
+       /* Balance internal level of the tree. */
+       for (h = 1; h < MAX_HEIGHT && tb->insert_size[h]; h++)
+               child_pos = balance_internal(tb, h, child_pos, insert_key,
+                                            insert_ptr);
+
+       do_balance_completed(tb);
+}