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linux/fs/reiserfs/fix_node.c
Gustavo A. R. Silva 76d2ceda72 reiserfs: Replace one-element array with flexible-array member 
One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in direntry_uarea structure, and refactor the rest of the code,
accordingly.

Worth mentioning is that before these changes, the original implementation
was returning two-too many bytes in function direntry_create_vi():

fs/reiserfs/item_ops.c:464:     int size = sizeof(struct direntry_uarea);
...
fs/reiserfs/item_ops.c-490-     size += (dir_u->entry_count * sizeof(short));
...
fs/reiserfs/item_ops.c-517-     return size;

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/290
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2023-07-12 13:09:46 -06:00

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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 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);
}
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