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fix_node.c
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fix_node.c
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/*
* 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 cur_free;
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;
cur_free = max_node_size;
/* start from 'from'-th item */
start_item = from;
/* skip its first 'start_bytes' units */
start_bytes = ((from_bytes != -1) ? from_bytes : 0);
/* last included item is the 'end_item'-th one */
end_item = vn->vn_nr_item - to - 1;
/* do not count last 'end_bytes' units of 'end_item'-th item */
end_bytes = (to_bytes != -1) ? to_bytes : 0;
/*
* go through all item beginning from the start_item-th item
* and ending by the end_item-th item. Do not count first
* 'start_bytes' units of 'start_item'-th item and last
* 'end_bytes' of 'end_item'-th item
*/
for (i = start_item; i <= end_item; i++) {
struct virtual_item *vi = vn->vn_vi + i;
int skip_from_end = ((i == end_item) ? end_bytes : 0);
RFALSE(needed_nodes > 3, "vs-8105: too many nodes are needed");
/* get size of current item */
current_item_size = vi->vi_item_len;
/*
* do not take in calculation head part (from_bytes)
* of from-th item
*/
current_item_size -=
op_part_size(vi, 0 /*from start */ , start_bytes);
/* do not take in calculation tail part of last item */
current_item_size -=
op_part_size(vi, 1 /*from end */ , skip_from_end);
/* if item fits into current node entierly */
if (total_node_size + current_item_size <= max_node_size) {
snum012[needed_nodes - 1]++;
total_node_size += current_item_size;
start_bytes = 0;
continue;
}
/*
* 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 not shifted entirely
* rbytes number of bytes which flow to the right neighbor from the
* item that is not not shifted entirely
* s1bytes number of bytes which flow to the first new node when
* S[0] splits (this number is contained in s012 array)
*/
static void set_parameters(struct tree_balance *tb, int h, int lnum,
int rnum, int blk_num, short *s012, int lb, int rb)
{
tb->lnum[h] = lnum;
tb->rnum[h] = rnum;
tb->blknum[h] = blk_num;
/* 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;
}