/*
 * 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);
}