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