diff options
Diffstat (limited to 'fs/reiserfs/fix_node.c')
| -rw-r--r-- | fs/reiserfs/fix_node.c | 967 |
1 files changed, 598 insertions, 369 deletions
diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c index b6a05a7f465..144bd62c3e3 100644 --- a/fs/reiserfs/fix_node.c +++ b/fs/reiserfs/fix_node.c @@ -2,59 +2,32 @@ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README */ -/** - ** old_item_num - ** old_entry_num - ** set_entry_sizes - ** create_virtual_node - ** check_left - ** check_right - ** directory_part_size - ** get_num_ver - ** set_parameters - ** is_leaf_removable - ** are_leaves_removable - ** get_empty_nodes - ** get_lfree - ** get_rfree - ** is_left_neighbor_in_cache - ** decrement_key - ** get_far_parent - ** get_parents - ** can_node_be_removed - ** ip_check_balance - ** dc_check_balance_internal - ** dc_check_balance_leaf - ** dc_check_balance - ** check_balance - ** get_direct_parent - ** get_neighbors - ** fix_nodes - ** - ** - **/ - #include <linux/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. */ - -/* taking item number in virtual node, returns number of item, that it has in source buffer */ +/* + * 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) @@ -112,7 +85,10 @@ static void create_virtual_node(struct tree_balance *tb, int h) && (vn->vn_mode != M_DELETE || vn->vn_affected_item_num)) vn->vn_vi[0].vi_type |= VI_TYPE_LEFT_MERGEABLE; - /* go through all items those remain in the virtual node (except for the new (inserted) one) */ + /* + * 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; @@ -131,8 +107,10 @@ static void create_virtual_node(struct tree_balance *tb, int h) 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 + /* + * 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) @@ -145,7 +123,8 @@ static void create_virtual_node(struct tree_balance *tb, int h) if (vn->vn_mode == M_PASTE || vn->vn_mode == M_CUT) { vn->vn_vi[new_num].vi_item_len += tb->insert_size[0]; - vi->vi_new_data = vn->vn_data; // pointer to data which is going to be pasted + /* pointer to data which is going to be pasted */ + vi->vi_new_data = vn->vn_data; } } @@ -164,7 +143,10 @@ static void create_virtual_node(struct tree_balance *tb, int h) tb->insert_size[0]); } - /* set right merge flag we take right delimiting key and check whether it is a mergeable item */ + /* + * 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; @@ -179,12 +161,19 @@ static void create_virtual_node(struct tree_balance *tb, int h) 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 */ + /* + * 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 */ + /* + * 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 " @@ -198,8 +187,10 @@ static void create_virtual_node(struct tree_balance *tb, int h) } } -/* using virtual node check, how many items can be shifted to left - neighbor */ +/* + * 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; @@ -259,9 +250,13 @@ static void check_left(struct tree_balance *tb, int h, int cur_free) } /* 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 */ + /* + * 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) { - /* cannot shift even a part of the current item */ tb->lbytes = -1; return; } @@ -278,8 +273,10 @@ static void check_left(struct tree_balance *tb, int h, int cur_free) return; } -/* using virtual node check, how many items can be shifted to right - neighbor */ +/* + * 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; @@ -338,13 +335,21 @@ static void check_right(struct tree_balance *tb, int h, int cur_free) continue; } - /* check whether R[0] can hold ih and at least one byte of the item body */ - if (cur_free <= ih_size) { /* cannot shift even a part of the current item */ + /* + * 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 */ + /* + * 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); @@ -361,45 +366,64 @@ static void check_right(struct tree_balance *tb, int h, int cur_free) /* * 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 */ + * from_bytes - number of bytes of boundary item (or directory entries) + * which are shifted to left neighbor + * to_bytes - number of bytes of boundary item (or directory entries) + * which are shifted to right neighbor + */ static int get_num_ver(int mode, struct tree_balance *tb, int h, int from, int from_bytes, int to, int to_bytes, short *snum012, int flow) { int i; int cur_free; - // int bytes; int units; struct virtual_node *vn = tb->tb_vn; - // struct virtual_item * vi; - int total_node_size, max_node_size, current_item_size; int needed_nodes; - int start_item, /* position of item we start filling node from */ - end_item, /* position of item we finish filling node by */ - start_bytes, /* number of first bytes (entries for directory) of start_item-th item - we do not include into node that is being filled */ - end_bytes; /* number of last bytes (entries for directory) of end_item-th item - we do node include into node that is being filled */ - int split_item_positions[2]; /* these are positions in virtual item of - items, that are split between S[0] and - S1new and S1new and S2new */ + + /* 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. */ + /* + * 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 [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 */ @@ -416,20 +440,22 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, total_node_size = 0; cur_free = max_node_size; - // start from 'from'-th item + /* start from 'from'-th item */ start_item = from; - // skip its first 'start_bytes' units + /* skip its first 'start_bytes' units */ start_bytes = ((from_bytes != -1) ? from_bytes : 0); - // last included item is the 'end_item'-th one + /* 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 + /* 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 */ - + /* + * 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); @@ -439,7 +465,10 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, /* 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 */ + /* + * 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); @@ -455,9 +484,11 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, 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) { - /* virtual item length is longer, than max size of item in - a node. It is impossible for direct item */ RFALSE(is_direct_le_ih(vi->vi_ih), "vs-8110: " "direct item length is %d. It can not be longer than %d", @@ -466,15 +497,18 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, flow = 1; } + /* as we do not split items, take new node and continue */ if (!flow) { - /* as we do not split items, take new node and continue */ needed_nodes++; i--; total_node_size = 0; continue; } - // calculate number of item units which fit into node being - // filled + + /* + * calculate number of item units which fit into node being + * filled + */ { int free_space; @@ -482,17 +516,17 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, 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) { - /* nothing fits into current node, take new node and continue */ needed_nodes++, i--, total_node_size = 0; continue; } } /* something fits into the current node */ - //if (snum012[3] != -1 || needed_nodes != 1) - // reiserfs_panic (tb->tb_sb, "vs-8115: get_num_ver: too many nodes required"); - //snum012[needed_nodes - 1 + 3] = op_unit_num (vi) - start_bytes - units; start_bytes += units; snum012[needed_nodes - 1 + 3] = units; @@ -508,9 +542,11 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, 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 + /* + * 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; @@ -527,7 +563,7 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, ((split_item_positions[0] == split_item_positions[1]) ? snum012[3] : 0); - // s2bytes + /* s2bytes */ snum012[4] = op_unit_num(&vn->vn_vi[split_item_num]) - snum012[4] - bytes_to_r - bytes_to_l - bytes_to_S1new; @@ -555,7 +591,7 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, ((split_item_positions[0] == split_item_positions[1] && snum012[4] != -1) ? snum012[4] : 0); - // s1bytes + /* s1bytes */ snum012[3] = op_unit_num(&vn->vn_vi[split_item_num]) - snum012[3] - bytes_to_r - bytes_to_l - bytes_to_S2new; @@ -565,7 +601,8 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, } -/* Set parameters for balancing. +/* + * 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: @@ -575,11 +612,12 @@ static int get_num_ver(int mode, struct tree_balance *tb, int h, * rnum number of items from S[h] that must be shifted to R[h]; * blk_num number of blocks that S[h] will be splitted into; * s012 number of items that fall into splitted nodes. - * lbytes number of bytes which flow to the left neighbor from the item that is not - * not shifted entirely - * rbytes number of bytes which flow to the right neighbor from the item that is not - * not shifted entirely - * s1bytes number of bytes which flow to the first new node when S[0] splits (this number is contained in s012 array) + * lbytes number of bytes which flow to the left neighbor from the + * item that is not not shifted entirely + * rbytes number of bytes which flow to the right neighbor from the + * item that is not not shifted entirely + * s1bytes number of bytes which flow to the first new node when + * S[0] splits (this number is contained in s012 array) */ static void set_parameters(struct tree_balance *tb, int h, int lnum, @@ -590,7 +628,8 @@ static void set_parameters(struct tree_balance *tb, int h, int lnum, tb->rnum[h] = rnum; tb->blknum[h] = blk_num; - if (h == 0) { /* only for leaf level */ + /* only for leaf level */ + if (h == 0) { if (s012 != NULL) { tb->s0num = *s012++, tb->s1num = *s012++, tb->s2num = *s012++; @@ -607,8 +646,10 @@ static void set_parameters(struct tree_balance *tb, int h, int lnum, PROC_INFO_ADD(tb->tb_sb, rbytes[h], rb); } -/* check, does node disappear if we shift tb->lnum[0] items to left - neighbor and tb->rnum[0] to the right one. */ +/* + * 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; @@ -616,8 +657,10 @@ static int is_leaf_removable(struct tree_balance *tb) int size; int remain_items; - /* number of items, that will be shifted to left (right) neighbor - entirely */ + /* + * 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; @@ -625,18 +668,18 @@ static int is_leaf_removable(struct tree_balance *tb) /* 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) { - /* all content of node can be shifted to neighbors */ set_parameters(tb, 0, to_left, vn->vn_nr_item - to_left, 0, NULL, -1, -1); return 1; } + /* S[0] is not removable */ if (remain_items > 1 || tb->lbytes == -1 || tb->rbytes == -1) - /* S[0] is not removable */ return 0; - /* check, whether we can divide 1 remaining item between neighbors */ + /* 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])); @@ -680,18 +723,23 @@ static int are_leaves_removable(struct tree_balance *tb, int lfree, int rfree) && !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)) { - /* Directory must be in correct state here: that is - somewhere at the left side should exist first directory - item. But the item being deleted can not be that first - one because its right neighbor is item of the same - directory. (But first item always gets deleted in last - turn). So, neighbors of deleted item can be merged, so - we can save ih_size */ ih_size = IH_SIZE; - /* we might check that left neighbor exists and is of the - same directory */ + /* + * 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"); } @@ -770,7 +818,8 @@ static void free_buffers_in_tb(struct tree_balance *tb) } } -/* Get new buffers for storing new nodes that are created while balancing. +/* + * 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. @@ -778,28 +827,33 @@ static void free_buffers_in_tb(struct tree_balance *tb) /* 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); + 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, amount_needed, /* number of needed empty blocks */ - retval = CARRY_ON; + 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. */ + /* + * 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++) @@ -810,13 +864,19 @@ static int get_empty_nodes(struct tree_balance *tb, int h) /* 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. */ + /* + * 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. */ + 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 */ + /* + * 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; @@ -849,8 +909,10 @@ static int get_empty_nodes(struct tree_balance *tb, int h) return retval; } -/* Get free space of the left neighbor, which is stored in the parent - * node of the left neighbor. */ +/* + * 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; @@ -870,7 +932,8 @@ static int get_lfree(struct tree_balance *tb, int h) return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order))); } -/* Get free space of the right neighbor, +/* + * 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) @@ -916,7 +979,10 @@ static int is_left_neighbor_in_cache(struct tree_balance *tb, int 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. */ + /* + * 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. */ @@ -940,17 +1006,20 @@ static int is_left_neighbor_in_cache(struct tree_balance *tb, int h) static void decrement_key(struct cpu_key *key) { - // call item specific function for this 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 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; + * 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, @@ -966,8 +1035,10 @@ static int get_far_parent(struct tree_balance *tb, 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. */ + /* + * 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; @@ -975,21 +1046,33 @@ static int get_far_parent(struct tree_balance *tb, "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. */ + /* + * 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. */ + + /* + * 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. */ + + /* + * 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) { @@ -1002,7 +1085,10 @@ static int get_far_parent(struct tree_balance *tb, /* 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. */ + /* + * 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 == @@ -1031,8 +1117,11 @@ static int get_far_parent(struct tree_balance *tb, } } - /* So, we got common parent of the current node and its left/right neighbor. - Now we are geting the parent of the left/right neighbor. */ + /* + * 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, @@ -1050,7 +1139,7 @@ static int get_far_parent(struct tree_balance *tb, if (search_by_key (tb->tb_sb, &s_lr_father_key, &s_path_to_neighbor_father, h + 1) == IO_ERROR) - // path is released + /* path is released */ return IO_ERROR; if (FILESYSTEM_CHANGED_TB(tb)) { @@ -1071,12 +1160,15 @@ static int get_far_parent(struct tree_balance *tb, 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; +/* + * 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) { @@ -1088,8 +1180,11 @@ static int get_parents(struct tree_balance *tb, int h) /* 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. */ + /* + * 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]); @@ -1111,10 +1206,14 @@ static int get_parents(struct tree_balance *tb, int h) 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]. */ + /* + * 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) @@ -1130,19 +1229,22 @@ static int get_parents(struct tree_balance *tb, int h) (curcf && !B_IS_IN_TREE(curcf)), "PAP-8195: FL (%b) or CFL (%b) is invalid", curf, curcf); -/* Get parent FR[h] of R[h]. */ + /* Get parent FR[h] of R[h]. */ -/* Current node is the last child of F[h]. FR[h] != F[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]. */ + /* + * 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]. */ + /* 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); @@ -1165,8 +1267,10 @@ static int get_parents(struct tree_balance *tb, int h) return CARRY_ON; } -/* it is possible to remove node as result of shiftings to - neighbors even when we insert or paste item. */ +/* + * 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) { @@ -1189,7 +1293,8 @@ static inline int can_node_be_removed(int mode, int lfree, int sfree, int rfree, && 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 (sfree >= levbytes) { + /* new item fits into node S[h] without any shifting */ if (!h) tb->s0num = B_NR_ITEMS(Sh) + @@ -1202,7 +1307,8 @@ static inline int can_node_be_removed(int mode, int lfree, int sfree, int rfree, return !NO_BALANCING_NEEDED; } -/* Check whether current node S[h] is balanced when increasing its size by +/* + * 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: @@ -1219,39 +1325,48 @@ static inline int can_node_be_removed(int mode, int lfree, int sfree, int rfree, static int ip_check_balance(struct tree_balance *tb, int h) { struct virtual_node *vn = tb->tb_vn; - int levbytes, /* 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. */ - ret; + /* + * 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. */ + /* + * 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. */ + /* + * 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 + /* + * 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, }; /* 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; @@ -1265,9 +1380,10 @@ static int ip_check_balance(struct tree_balance *tb, int 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; /* no balancing for higher levels needed */ + return NO_BALANCING_NEEDED; case NO_DISK_SPACE: case REPEAT_SEARCH: @@ -1278,7 +1394,9 @@ static int ip_check_balance(struct tree_balance *tb, int h) } } - if ((ret = get_parents(tb, h)) != CARRY_ON) /* get parents of S[h] neighbors. */ + /* get parents of S[h] neighbors. */ + ret = get_parents(tb, h); + if (ret != CARRY_ON) return ret; sfree = B_FREE_SPACE(Sh); @@ -1287,38 +1405,44 @@ static int ip_check_balance(struct tree_balance *tb, int h) 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) - /* and new item fits into node S[h] without any shifting */ 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) + * 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) + * 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 */ + /* + * 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. */ + /* + * 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 - @@ -1328,7 +1452,10 @@ static int ip_check_balance(struct tree_balance *tb, int h) return CARRY_ON; } - /* this checks balance condition, that any two neighboring nodes can not fit in one node */ + /* + * 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), @@ -1337,16 +1464,22 @@ static int ip_check_balance(struct tree_balance *tb, int h) (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. */ + /* + * 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 */ - if (sfree >= levbytes) { /* new item fits into node S[h] without any shifting */ + /* + * 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); @@ -1355,18 +1488,19 @@ static int ip_check_balance(struct tree_balance *tb, int h) { int lpar, rpar, nset, lset, rset, lrset; - /* - * regular overflowing of the node - */ + /* 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 + /* + * 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 the following */ + /* we choose one of the following */ #define NOTHING_SHIFT_NO_FLOW 0 #define NOTHING_SHIFT_FLOW 5 #define LEFT_SHIFT_NO_FLOW 10 @@ -1379,10 +1513,13 @@ static int ip_check_balance(struct tree_balance *tb, int h) 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 */ + /* + * 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, @@ -1391,7 +1528,10 @@ static int ip_check_balance(struct tree_balance *tb, int h) if (!h) { int nver1; - /* note, that in this case we try to bottle between S[0] and S1 (S1 - the first new node) */ + /* + * 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); @@ -1399,11 +1539,13 @@ static int ip_check_balance(struct tree_balance *tb, int h) 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 + /* + * 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, @@ -1422,11 +1564,13 @@ static int ip_check_balance(struct tree_balance *tb, int h) 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 + /* + * 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, @@ -1451,10 +1595,12 @@ static int ip_check_balance(struct tree_balance *tb, int h) 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 + /* + * 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, @@ -1481,10 +1627,12 @@ static int ip_check_balance(struct tree_balance *tb, int h) 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; */ + /* + * 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) { @@ -1508,42 +1656,59 @@ static int ip_check_balance(struct tree_balance *tb, int h) return CARRY_ON; } - /* if shifting doesn't lead to better packing then don't shift */ + /* + * 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 */ + /* + * 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 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 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 */ + /* + * 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 */ + /* + * 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 +/* + * 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: @@ -1563,8 +1728,10 @@ 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. */ + /* + * Sh is the node whose balance is currently being checked, + * and Fh is its father. + */ struct buffer_head *Sh, *Fh; int maxsize, ret; int lfree, rfree /* free space in L and R */ ; @@ -1574,19 +1741,25 @@ static int dc_check_balance_internal(struct tree_balance *tb, int h) maxsize = MAX_CHILD_SIZE(Sh); -/* 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); */ + /* + * 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; /* no balancing for higher levels needed */ + return NO_BALANCING_NEEDED; } - /* new_nr_item == 0. + /* + * new_nr_item == 0. * Current root will be deleted resulting in - * decrementing the tree height. */ + * decrementing the tree height. + */ set_parameters(tb, h, 0, 0, 0, NULL, -1, -1); return CARRY_ON; } @@ -1602,12 +1775,18 @@ static int dc_check_balance_internal(struct tree_balance *tb, int h) check_left(tb, h, lfree); check_right(tb, h, rfree); - if (vn->vn_nr_item >= MIN_NR_KEY(Sh)) { /* 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. */ + /* + * 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) { - /* All contents of S[h] can be moved to L[h]. */ int n; int order_L; @@ -1623,8 +1802,8 @@ static int dc_check_balance_internal(struct tree_balance *tb, int h) return CARRY_ON; } + /* All contents of S[h] can be moved to R[h]. */ if (tb->rnum[h] >= vn->vn_nr_item + 1) { - /* All contents of S[h] can be moved to R[h]. */ int n; int order_R; @@ -1641,8 +1820,11 @@ static int dc_check_balance_internal(struct tree_balance *tb, int h) } } + /* + * 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) { - /* All contents of S[h] can be moved to the neighbors (L[h] & R[h]). */ int to_r; to_r = @@ -1659,7 +1841,10 @@ static int dc_check_balance_internal(struct tree_balance *tb, int h) return NO_BALANCING_NEEDED; } - /* Current node contain insufficient number of items. Balancing is required. */ + /* + * 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) @@ -1726,7 +1911,8 @@ static int dc_check_balance_internal(struct tree_balance *tb, int h) return CARRY_ON; } -/* Check whether current node S[h] is balanced when Decreasing its size by +/* + * 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: @@ -1743,15 +1929,21 @@ 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. */ + /* + * 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. */ + + /* + * 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 */ ; @@ -1784,9 +1976,11 @@ static int dc_check_balance_leaf(struct tree_balance *tb, int h) 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 + /* + * 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); @@ -1810,7 +2004,10 @@ static int dc_check_balance_leaf(struct tree_balance *tb, int h) return CARRY_ON; } - /* All contents of S[0] can be moved to the neighbors (L[0] & R[0]). Set parameters and return */ + /* + * 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; @@ -1820,7 +2017,8 @@ static int dc_check_balance_leaf(struct tree_balance *tb, int h) return NO_BALANCING_NEEDED; } -/* Check whether current node S[h] is balanced when Decreasing its size by +/* + * 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: @@ -1844,15 +2042,16 @@ static int dc_check_balance(struct tree_balance *tb, int h) return dc_check_balance_leaf(tb, h); } -/* Check whether current node S[h] is balanced. +/* + * 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 + * 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]; @@ -1882,8 +2081,8 @@ static int check_balance(int mode, 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) - /* Calculate balance parameters when size of node is increasing. */ return ip_check_balance(tb, h); /* Calculate balance parameters when size of node is decreasing. */ @@ -1911,21 +2110,23 @@ static int get_direct_parent(struct tree_balance *tb, int h) PATH_OFFSET_POSITION(path, path_offset - 1) = 0; return CARRY_ON; } - return REPEAT_SEARCH; /* Root is changed and we must recalculate the path. */ + /* 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; /* Parent in the path is not in the tree. */ + 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) - /* Parent in the path is not parent of the current node in the tree. */ return REPEAT_SEARCH; if (buffer_locked(bh)) { @@ -1936,10 +2137,15 @@ static int get_direct_parent(struct tree_balance *tb, int h) return REPEAT_SEARCH; } - return CARRY_ON; /* Parent in the path is unlocked and really parent of the current node. */ + /* + * 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 +/* + * 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; @@ -1997,7 +2203,7 @@ static int get_neighbors(struct tree_balance *tb, int h) } /* We need right neighbor to balance S[path_offset]. */ - if (tb->rnum[h]) { /* 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); @@ -2053,9 +2259,11 @@ static int get_virtual_node_size(struct super_block *sb, struct buffer_head *bh) (max_num_of_entries - 1) * sizeof(__u16)); } -/* 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 */ +/* + * 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; @@ -2064,8 +2272,8 @@ static int get_mem_for_virtual_node(struct tree_balance *tb) 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) { - /* we have to allocate more memory for virtual node */ if (tb->vn_buf) { /* free memory allocated before */ kfree(tb->vn_buf); @@ -2079,10 +2287,12 @@ static int get_mem_for_virtual_node(struct tree_balance *tb) /* 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 */ + /* + * 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) { @@ -2168,8 +2378,10 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb) 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 + /* + * 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) == @@ -2256,13 +2468,15 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb) } } } - /* 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 + + /* + * 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]) { @@ -2300,7 +2514,8 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb) return CARRY_ON; } -/* Prepare for balancing, that is +/* + * Prepare for balancing, that is * get all necessary parents, and neighbors; * analyze what and where should be moved; * get sufficient number of new nodes; @@ -2309,13 +2524,14 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb) * 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 + * 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 + * 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) @@ -2335,8 +2551,9 @@ int fix_nodes(int op_mode, struct tree_balance *tb, 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 + /* + * 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); @@ -2347,10 +2564,11 @@ int fix_nodes(int op_mode, struct tree_balance *tb, 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 + /* + * 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); @@ -2408,7 +2626,7 @@ int fix_nodes(int op_mode, struct tree_balance *tb, #endif if (get_mem_for_virtual_node(tb) == REPEAT_SEARCH) - // FIXME: maybe -ENOMEM when tb->vn_buf == 0? Now just repeat + /* 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. */ @@ -2427,7 +2645,10 @@ int fix_nodes(int op_mode, struct tree_balance *tb, goto repeat; if (h != MAX_HEIGHT - 1) tb->insert_size[h + 1] = 0; - /* ok, analysis and resource gathering are complete */ + /* + * ok, analysis and resource gathering + * are complete + */ break; } goto repeat; @@ -2437,15 +2658,19 @@ int fix_nodes(int op_mode, struct tree_balance *tb, if (ret != CARRY_ON) goto repeat; - /* No disk space, or schedule occurred and analysis may be - * invalid and needs to be redone. */ + /* + * 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)) { - /* We have a positive insert size but no nodes exist on this - level, this means that we are creating a new root. */ RFALSE(tb->blknum[h] != 1, "PAP-8350: creating new empty root"); @@ -2453,11 +2678,13 @@ int fix_nodes(int op_mode, struct tree_balance *tb, 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) { - /* 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. */ RFALSE(h == MAX_HEIGHT - 1, "PAP-8355: attempt to create too high of a tree"); @@ -2488,11 +2715,13 @@ int fix_nodes(int op_mode, struct tree_balance *tb, } 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 + /* + * 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; @@ -2548,8 +2777,6 @@ int fix_nodes(int op_mode, struct tree_balance *tb, } -/* Anatoly will probably forgive me renaming tb to tb. I just - wanted to make lines shorter */ void unfix_nodes(struct tree_balance *tb) { int i; @@ -2578,8 +2805,10 @@ void unfix_nodes(struct tree_balance *tb) 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 */ + /* + * 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); |