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reiserfsprogs/reiserfscore/lbalance.c
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/*
* Copyright 1996-2003 by Hans Reiser, licensing governed by
* reiserfsprogs/README
*/
#include "includes.h"
/* these are used in do_balance.c */
/* leaf_move_items
leaf_shift_left
leaf_shift_right
leaf_delete_items
leaf_insert_into_buf
leaf_paste_in_buffer
leaf_cut_from_buffer
leaf_paste_entries
*/
extern struct tree_balance init_tb;
extern int init_item_pos;
extern int init_pos_in_item;
extern int init_mode;
/* copy copy_count entries from source directory item to dest buffer (creating new item if needed) */
static void leaf_copy_dir_entries (reiserfs_filsys_t * fs,
struct buffer_info * dest_bi, struct buffer_head * source,
int last_first, int item_num, int from, int copy_count)
{
struct buffer_head * dest = dest_bi->bi_bh;
int item_num_in_dest; /* either the number of target item,
or if we must create a new item,
the number of the item we will
create it next to */
struct item_head * ih;
struct reiserfs_de_head * deh;
int copy_records_len; /* length of all records in item to be copied */
char * records;
ih = B_N_PITEM_HEAD (source, item_num);
/* length of all record to be copied and first byte of the last of them */
deh = B_I_DEH (source, ih);
if (copy_count) {
copy_records_len = (from ? get_deh_location (&deh[from - 1]) : get_ih_item_len (ih)) -
get_deh_location (&deh[from + copy_count - 1]);
records = source->b_data + get_ih_location (ih) + get_deh_location (&deh[from + copy_count - 1]);
} else {
copy_records_len = 0;
records = 0;
}
/* when copy last to first, dest buffer can contain 0 items */
item_num_in_dest = (last_first == LAST_TO_FIRST) ? (( B_NR_ITEMS(dest) ) ? 0 : -1) : (B_NR_ITEMS(dest) - 1);
/* if there are no items in dest or the first/last item in dest is not item of the same directory */
if ( (item_num_in_dest == - 1) ||
(last_first == FIRST_TO_LAST && are_items_mergeable (B_N_PITEM_HEAD (dest, item_num_in_dest), ih, dest->b_size) == 0) ||
(last_first == LAST_TO_FIRST && are_items_mergeable (ih, B_N_PITEM_HEAD (dest, item_num_in_dest), dest->b_size) == 0)) {
/* create new item in dest */
struct item_head new_ih;
/* form item header */
memcpy (&new_ih.ih_key, &ih->ih_key, KEY_SIZE);
/* calculate item len */
set_ih_item_len (&new_ih, DEH_SIZE * copy_count + copy_records_len);
set_ih_entry_count (&new_ih, 0);
if (last_first == LAST_TO_FIRST) {
/* form key by the following way */
if (from < get_ih_entry_count (ih)) {
set_key_offset_v1 (&new_ih.ih_key, get_deh_offset (&deh[from]));
} else {
/* no entries will be copied to this item in this function */
set_key_offset_v1 (&new_ih.ih_key, MAX_KEY1_OFFSET);
}
set_key_uniqueness (&new_ih.ih_key, DIRENTRY_UNIQUENESS);
}
set_ih_key_format (&new_ih, get_ih_key_format (ih));
set_ih_flags (&new_ih, get_ih_flags (ih));
/* insert item into dest buffer */
leaf_insert_into_buf (fs, dest_bi, (last_first == LAST_TO_FIRST) ? 0 : B_NR_ITEMS(dest), &new_ih, NULL, 0);
} else {
/* prepare space for entries */
leaf_paste_in_buffer (fs, dest_bi, (last_first == FIRST_TO_LAST) ? (B_NR_ITEMS(dest) - 1) : 0, 0xffff /*MAX_US_INT */,
DEH_SIZE * copy_count + copy_records_len, records, 0);
}
item_num_in_dest = (last_first == FIRST_TO_LAST) ? (B_NR_ITEMS(dest)-1) : 0;
leaf_paste_entries (dest_bi->bi_bh, item_num_in_dest,
(last_first == FIRST_TO_LAST) ? get_ih_entry_count (B_N_PITEM_HEAD (dest, item_num_in_dest)) : 0,
copy_count, deh + from, records,
DEH_SIZE * copy_count + copy_records_len
);
}
/* Copy the first (if last_first == FIRST_TO_LAST) or last (last_first == LAST_TO_FIRST) item or
part of it or nothing (see the return 0 below) from SOURCE to the end
(if last_first) or beginning (!last_first) of the DEST */
/* returns 1 if anything was copied, else 0 */
static int leaf_copy_boundary_item (reiserfs_filsys_t * fs,
struct buffer_info * dest_bi, struct buffer_head * src, int last_first,
int bytes_or_entries)
{
struct buffer_head * dest = dest_bi->bi_bh;
int dest_nr_item, src_nr_item; /* number of items in the source and destination buffers */
struct item_head * ih;
struct item_head * dih;
dest_nr_item = B_NR_ITEMS(dest);
if ( last_first == FIRST_TO_LAST ) {
/* if ( DEST is empty or first item of SOURCE and last item of DEST are the items of different objects
or of different types ) then there is no need to treat this item differently from the other items
that we copy, so we return */
ih = B_N_PITEM_HEAD (src, 0);
dih = B_N_PITEM_HEAD (dest, dest_nr_item - 1);
if (!dest_nr_item || (are_items_mergeable (dih, ih, src->b_size) == 0))
/* there is nothing to merge */
return 0;
if ( I_IS_DIRECTORY_ITEM(ih) ) {
if ( bytes_or_entries == -1 )
/* copy all entries to dest */
bytes_or_entries = get_ih_entry_count(ih);
leaf_copy_dir_entries (fs, dest_bi, src, FIRST_TO_LAST, 0, 0, bytes_or_entries);
return 1;
}
/* copy part of the body of the first item of SOURCE to the end of the body of the last item of the DEST
part defined by 'bytes_or_entries'; if bytes_or_entries == -1 copy whole body; don't create new item header
*/
if ( bytes_or_entries == -1 )
bytes_or_entries = get_ih_item_len (ih);
/* merge first item (or its part) of src buffer with the last
item of dest buffer. Both are of the same file */
leaf_paste_in_buffer (fs, dest_bi, dest_nr_item - 1, get_ih_item_len (dih),
bytes_or_entries, B_I_PITEM(src,ih), 0);
if (I_IS_INDIRECT_ITEM(dih)) {
if (bytes_or_entries == get_ih_item_len (ih))
//dih->u.ih_free_space = ih->u.ih_free_space;
set_ih_free_space (dih, get_ih_free_space (ih));
}
return 1;
}
/* copy boundary item to right (last_first == LAST_TO_FIRST) */
/* ( DEST is empty or last item of SOURCE and first item of DEST
are the items of different object or of different types )
*/
src_nr_item = B_NR_ITEMS (src);
ih = B_N_PITEM_HEAD (src, src_nr_item - 1);
dih = B_N_PITEM_HEAD (dest, 0);
if (!dest_nr_item || are_items_mergeable (ih, dih, src->b_size) == 0)
return 0;
if ( I_IS_DIRECTORY_ITEM(ih)) {
if ( bytes_or_entries == -1 )
/* bytes_or_entries = entries number in last item body of SOURCE */
bytes_or_entries = get_ih_entry_count(ih);
leaf_copy_dir_entries (fs, dest_bi, src, LAST_TO_FIRST, src_nr_item - 1, get_ih_entry_count(ih) - bytes_or_entries,
bytes_or_entries);
return 1;
}
/* copy part of the body of the last item of SOURCE to the begin of the body of the first item of the DEST;
part defined by 'bytes_or_entries'; if byte_or_entriess == -1 copy whole body; change first item key of the DEST;
don't create new item header
*/
if ( bytes_or_entries == -1 ) {
/* bytes_or_entries = length of last item body of SOURCE */
bytes_or_entries = get_ih_item_len (ih);
/* change first item key of the DEST */
//dih->ih_key.k_offset = ih->ih_key.k_offset;
set_offset (key_format (&dih->ih_key), &dih->ih_key, get_offset (&ih->ih_key));
/* item becomes non-mergeable */
/* or mergeable if left item was */
//dih->ih_key.k_uniqueness = ih->ih_key.k_uniqueness;
set_type (key_format (&dih->ih_key), &dih->ih_key, get_type (&ih->ih_key));
} else {
/* merge to right only part of item */
/* change first item key of the DEST */
if ( I_IS_DIRECT_ITEM(dih) ) {
//dih->ih_key.k_offset -= bytes_or_entries;
set_offset (key_format (&dih->ih_key), &dih->ih_key, get_offset (&dih->ih_key) - bytes_or_entries);
} else {
//dih->ih_key.k_offset -= ((bytes_or_entries/UNFM_P_SIZE)*dest->b_size);
set_offset (key_format (&dih->ih_key), &dih->ih_key,
get_offset (&dih->ih_key) - ((bytes_or_entries/UNFM_P_SIZE)*dest->b_size));
}
}
leaf_paste_in_buffer (fs, dest_bi, 0, 0, bytes_or_entries, B_I_PITEM(src,ih) + get_ih_item_len (ih) - bytes_or_entries, 0);
return 1;
}
/* copy cpy_mun items from buffer src to buffer dest
* last_first == FIRST_TO_LAST means, that we copy cpy_num items beginning from first-th item in src to tail of dest
* last_first == LAST_TO_FIRST means, that we copy cpy_num items beginning from first-th item in src to head of dest
*/
static void leaf_copy_items_entirely (reiserfs_filsys_t * fs, struct buffer_info * dest_bi,
struct buffer_head * src, int last_first,
int first, int cpy_num)
{
struct buffer_head * dest;
int nr;
int dest_before;
int last_loc, last_inserted_loc, location;
int i, j;
struct block_head * blkh;
struct item_head * ih;
dest = dest_bi->bi_bh;
if (cpy_num == 0)
return;
blkh = B_BLK_HEAD(dest);
nr = get_blkh_nr_items (blkh);
/* we will insert items before 0-th or nr-th item in dest buffer. It depends of last_first parameter */
dest_before = (last_first == LAST_TO_FIRST) ? 0 : nr;
/* location of head of first new item */
ih = B_N_PITEM_HEAD (dest, dest_before);
/* prepare space for headers */
memmove (ih + cpy_num, ih, (nr-dest_before) * IH_SIZE);
/* copy item headers */
memcpy (ih, B_N_PITEM_HEAD (src, first), cpy_num * IH_SIZE);
set_blkh_free_space (blkh, get_blkh_free_space (blkh) - IH_SIZE * cpy_num);
/* location of unmovable item */
j = location = (dest_before == 0) ? dest->b_size : get_ih_location (ih-1);
for (i = dest_before; i < nr + cpy_num; i ++) {
location -= get_ih_item_len (&ih[i-dest_before]);
set_ih_location (&ih[i-dest_before], location);
}
/* prepare space for items */
last_loc = get_ih_location (&ih[nr+cpy_num-1-dest_before]);
last_inserted_loc = get_ih_location (&ih[cpy_num-1]);
/* check free space */
memmove (dest->b_data + last_loc,
dest->b_data + last_loc + j - last_inserted_loc,
last_inserted_loc - last_loc);
/* copy items */
memcpy (dest->b_data + last_inserted_loc, B_N_PITEM(src,(first + cpy_num - 1)),
j - last_inserted_loc);
/* sizes, item number */
set_blkh_nr_items (blkh, get_blkh_nr_items (blkh) + cpy_num);
set_blkh_free_space (blkh,
get_blkh_free_space (blkh) - (j - last_inserted_loc));
mark_buffer_dirty (dest);
if (dest_bi->bi_parent) {
struct disk_child * dc;
dc = B_N_CHILD (dest_bi->bi_parent, dest_bi->bi_position);
set_dc_child_size (dc, get_dc_child_size (dc) + j - last_inserted_loc + IH_SIZE * cpy_num);
mark_buffer_dirty(dest_bi->bi_parent);
}
}
/* This function splits the (liquid) item into two items (useful when
shifting part of an item into another node.) */
static void leaf_item_bottle (reiserfs_filsys_t * fs,
struct buffer_info * dest_bi, struct buffer_head * src, int last_first,
int item_num, int cpy_bytes)
{
struct buffer_head * dest = dest_bi->bi_bh;
struct item_head * ih;
if ( last_first == FIRST_TO_LAST ) {
/* if ( if item in position item_num in buffer SOURCE is directory item ) */
if (I_IS_DIRECTORY_ITEM(ih = B_N_PITEM_HEAD(src,item_num)))
leaf_copy_dir_entries (fs, dest_bi, src, FIRST_TO_LAST, item_num, 0, cpy_bytes);
else {
struct item_head n_ih;
/* copy part of the body of the item number 'item_num' of SOURCE to the end of the DEST
part defined by 'cpy_bytes'; create new item header; change old item_header (????);
n_ih = new item_header;
*/
memcpy (&n_ih, ih, IH_SIZE);
set_ih_item_len (&n_ih, cpy_bytes);
if (I_IS_INDIRECT_ITEM(ih)) {
//n_ih.u.ih_free_space = 0;
set_ih_free_space (&n_ih, 0);;
}
//n_ih.ih_version = ih->ih_version;
set_ih_key_format (&n_ih, get_ih_key_format (ih));
set_ih_flags (&n_ih, get_ih_flags (ih));
leaf_insert_into_buf (fs, dest_bi, B_NR_ITEMS(dest), &n_ih, B_N_PITEM (src, item_num), 0);
}
} else {
/* if ( if item in position item_num in buffer SOURCE is directory item ) */
if (I_IS_DIRECTORY_ITEM(ih = B_N_PITEM_HEAD (src, item_num)))
leaf_copy_dir_entries (fs, dest_bi, src, LAST_TO_FIRST, item_num, get_ih_entry_count(ih) - cpy_bytes, cpy_bytes);
else {
struct item_head n_ih;
/* copy part of the body of the item number 'item_num' of SOURCE to the begin of the DEST
part defined by 'cpy_bytes'; create new item header;
n_ih = new item_header;
*/
memcpy (&n_ih, ih, SHORT_KEY_SIZE);
if (I_IS_DIRECT_ITEM(ih)) {
//n_ih.ih_key.k_offset = ih->ih_key.k_offset + ih->ih_item_len - cpy_bytes;
set_offset (key_format (&ih->ih_key), &n_ih.ih_key, get_offset (&ih->ih_key) + get_ih_item_len (ih) - cpy_bytes);
//n_ih.ih_key.k_uniqueness = TYPE_DIRECT;
set_type (key_format (&ih->ih_key), &n_ih.ih_key, TYPE_DIRECT);
//n_ih.u.ih_free_space = USHRT_MAX;
set_ih_free_space (&n_ih, USHRT_MAX);
} else {
/* indirect item */
//n_ih.ih_key.k_offset = ih->ih_key.k_offset + (ih->ih_item_len - cpy_bytes) / UNFM_P_SIZE * dest->b_size;
set_offset (key_format (&ih->ih_key), &n_ih.ih_key,
get_offset (&ih->ih_key) + (get_ih_item_len (ih) - cpy_bytes) / UNFM_P_SIZE * dest->b_size);
//n_ih.ih_key.k_uniqueness = TYPE_INDIRECT;
set_type (key_format (&ih->ih_key), &n_ih.ih_key, TYPE_INDIRECT);
//n_ih.u.ih_free_space = ih->u.ih_free_space;
set_ih_free_space (&n_ih, get_ih_free_space (ih));
}
/* set item length */
set_ih_item_len (&n_ih, cpy_bytes);
//n_ih.ih_version = ih->ih_version;
set_ih_key_format (&n_ih, get_ih_key_format (ih));
set_ih_flags (&n_ih, get_ih_flags (ih));
leaf_insert_into_buf (fs, dest_bi, 0, &n_ih, B_N_PITEM(src,item_num) + get_ih_item_len (ih) - cpy_bytes, 0);
}
}
}
/* If cpy_bytes equals minus one than copy cpy_num whole items from SOURCE to DEST.
If cpy_bytes not equal to minus one than copy cpy_num-1 whole items from SOURCE to DEST.
From last item copy cpy_num bytes for regular item and cpy_num directory entries for
directory item. */
static int leaf_copy_items (reiserfs_filsys_t * fs,
struct buffer_info * dest_bi, struct buffer_head * src,
int last_first, int cpy_num,
int cpy_bytes)
{
struct buffer_head * dest;
int pos, i, src_nr_item, bytes;
dest = dest_bi->bi_bh;
if ( cpy_num == 0 )
return 0;
if ( last_first == FIRST_TO_LAST ) {
/* copy items to left */
pos = 0;
if ( cpy_num == 1 )
bytes = cpy_bytes;
else
bytes = -1;
/* copy the first item or it part or nothing to the end of the DEST (i = leaf_copy_boundary_item(DEST,SOURCE,0,bytes)) */
i = leaf_copy_boundary_item (fs, dest_bi, src, FIRST_TO_LAST, bytes);
cpy_num -= i;
if ( cpy_num == 0 )
return i;
pos += i;
if ( cpy_bytes == -1 )
/* copy first cpy_num items starting from position 'pos' of SOURCE to end of DEST */
leaf_copy_items_entirely(fs, dest_bi, src, FIRST_TO_LAST, pos, cpy_num);
else {
/* copy first cpy_num-1 items starting from position 'pos-1' of the SOURCE to the end of the DEST */
leaf_copy_items_entirely(fs, dest_bi, src, FIRST_TO_LAST, pos, cpy_num-1);
/* copy part of the item which number is cpy_num+pos-1 to the end of the DEST */
leaf_item_bottle (fs, dest_bi, src, FIRST_TO_LAST, cpy_num+pos-1, cpy_bytes);
}
} else {
/* copy items to right */
src_nr_item = B_NR_ITEMS (src);
if ( cpy_num == 1 )
bytes = cpy_bytes;
else
bytes = -1;
/* copy the last item or it part or nothing to the begin of the DEST (i = leaf_copy_boundary_item(DEST,SOURCE,1,bytes)); */
i = leaf_copy_boundary_item (fs, dest_bi, src, LAST_TO_FIRST, bytes);
cpy_num -= i;
if ( cpy_num == 0 )
return i;
pos = src_nr_item - cpy_num - i;
if ( cpy_bytes == -1 ) {
/* starting from position 'pos' copy last cpy_num items of SOURCE to begin of DEST */
leaf_copy_items_entirely(fs, dest_bi, src, LAST_TO_FIRST, pos, cpy_num);
} else {
/* copy last cpy_num-1 items starting from position 'pos+1' of the SOURCE to the begin of the DEST; */
leaf_copy_items_entirely(fs, dest_bi, src, LAST_TO_FIRST, pos+1, cpy_num-1);
/* copy part of the item which number is pos to the begin of the DEST */
leaf_item_bottle (fs, dest_bi, src, LAST_TO_FIRST, pos, cpy_bytes);
}
}
return i;
}
/* there are types of coping: from S[0] to L[0], from S[0] to R[0],
from R[0] to L[0]. for each of these we have to define parent and
positions of destination and source buffers */
static void leaf_define_dest_src_infos (int shift_mode, struct tree_balance * tb, struct buffer_info * dest_bi,
struct buffer_info * src_bi, int * first_last,
struct buffer_head * Snew)
{
/* define dest, src, dest parent, dest position */
switch (shift_mode) {
case LEAF_FROM_S_TO_L: /* it is used in leaf_shift_left */
src_bi->bi_bh = PATH_PLAST_BUFFER (tb->tb_path);
src_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, 0);
src_bi->bi_position = PATH_H_B_ITEM_ORDER (tb->tb_path, 0); /* src->b_item_order */
dest_bi->bi_bh = tb->L[0];
dest_bi->bi_parent = tb->FL[0];
dest_bi->bi_position = get_left_neighbor_position (tb, 0);
*first_last = FIRST_TO_LAST;
break;
case LEAF_FROM_S_TO_R: /* it is used in leaf_shift_right */
src_bi->bi_bh = PATH_PLAST_BUFFER (tb->tb_path);
src_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, 0);
src_bi->bi_position = PATH_H_B_ITEM_ORDER (tb->tb_path, 0);
dest_bi->bi_bh = tb->R[0];
dest_bi->bi_parent = tb->FR[0];
dest_bi->bi_position = get_right_neighbor_position (tb, 0);
*first_last = LAST_TO_FIRST;
break;
case LEAF_FROM_R_TO_L: /* it is used in balance_leaf_when_delete */
src_bi->bi_bh = tb->R[0];
src_bi->bi_parent = tb->FR[0];
src_bi->bi_position = get_right_neighbor_position (tb, 0);
dest_bi->bi_bh = tb->L[0];
dest_bi->bi_parent = tb->FL[0];
dest_bi->bi_position = get_left_neighbor_position (tb, 0);
*first_last = FIRST_TO_LAST;
break;
case LEAF_FROM_L_TO_R: /* it is used in balance_leaf_when_delete */
src_bi->bi_bh = tb->L[0];
src_bi->bi_parent = tb->FL[0];
src_bi->bi_position = get_left_neighbor_position (tb, 0);
dest_bi->bi_bh = tb->R[0];
dest_bi->bi_parent = tb->FR[0];
dest_bi->bi_position = get_right_neighbor_position (tb, 0);
*first_last = LAST_TO_FIRST;
break;
case LEAF_FROM_S_TO_SNEW:
src_bi->bi_bh = PATH_PLAST_BUFFER (tb->tb_path);
src_bi->bi_parent = PATH_H_PPARENT (tb->tb_path, 0);
src_bi->bi_position = PATH_H_B_ITEM_ORDER (tb->tb_path, 0);
dest_bi->bi_bh = Snew;
dest_bi->bi_parent = 0;
dest_bi->bi_position = 0;
*first_last = LAST_TO_FIRST;
break;
default:
reiserfs_panic (0, "vs-10250: leaf_define_dest_src_infos: shift type is unknown (%d)", shift_mode);
}
}
/* copy mov_num items and mov_bytes of the (mov_num-1)th item to
neighbor. Delete them from source */
int leaf_move_items (int shift_mode, struct tree_balance * tb,
int mov_num, int mov_bytes, struct buffer_head * Snew)
{
int ret_value;
struct buffer_info dest_bi, src_bi;
int first_last;
leaf_define_dest_src_infos (shift_mode, tb, &dest_bi, &src_bi, &first_last, Snew);
ret_value = leaf_copy_items (tb->tb_fs, &dest_bi, src_bi.bi_bh, first_last, mov_num, mov_bytes);
leaf_delete_items (tb->tb_fs, &src_bi, first_last, (first_last == FIRST_TO_LAST) ? 0 :
(B_NR_ITEMS(src_bi.bi_bh) - mov_num), mov_num, mov_bytes);
return ret_value;
}
/* Shift shift_num items (and shift_bytes of last shifted item if shift_bytes != -1)
from S[0] to L[0] and replace the delimiting key */
int leaf_shift_left (struct tree_balance * tb, int shift_num, int shift_bytes)
{
struct buffer_head * S0 = PATH_PLAST_BUFFER (tb->tb_path);
int i;
/* move shift_num (and shift_bytes bytes) items from S[0] to left neighbor L[0] */
i = leaf_move_items (LEAF_FROM_S_TO_L, tb, shift_num, shift_bytes, 0);
if ( shift_num ) {
if (B_NR_ITEMS (S0) == 0) {
/* everything is moved from S[0] */
if (PATH_H_POSITION (tb->tb_path, 1) == 0)
replace_key(tb->tb_fs, tb->CFL[0], tb->lkey[0], PATH_H_PPARENT (tb->tb_path, 0), 0);
} else {
/* replace lkey in CFL[0] by 0-th key from S[0]; */
replace_key(tb->tb_fs, tb->CFL[0], tb->lkey[0], S0, 0);
}
}
return i;
}
/* CLEANING STOPPED HERE */
/* Shift shift_num (shift_bytes) items from S[0] to the right neighbor, and replace the delimiting key */
int leaf_shift_right (struct tree_balance * tb, int shift_num, int shift_bytes)
{
int ret_value;
/* move shift_num (and shift_bytes) items from S[0] to right neighbor R[0] */
ret_value = leaf_move_items (LEAF_FROM_S_TO_R, tb, shift_num, shift_bytes, 0);
/* replace rkey in CFR[0] by the 0-th key from R[0] */
if (shift_num) {
replace_key(tb->tb_fs, tb->CFR[0], tb->rkey[0], tb->R[0], 0);
}
return ret_value;
}
static void leaf_delete_items_entirely (reiserfs_filsys_t * sb,
/*struct reiserfs_transaction_handle *th,*/
struct buffer_info * bi,
int first,
int del_num);
/* If del_bytes == -1, starting from position 'first' delete del_num items in whole in buffer CUR.
If not.
If last_first == 0. Starting from position 'first' delete del_num-1 items in whole. Delete part of body of
the first item. Part defined by del_bytes. Don't delete first item header
If last_first == 1. Starting from position 'first+1' delete del_num-1 items in whole. Delete part of body of
the last item . Part defined by del_bytes. Don't delete last item header.
*/
void leaf_delete_items (reiserfs_filsys_t * fs,
struct buffer_info * cur_bi,
int last_first,
int first, int del_num, int del_bytes)
{
struct buffer_head * bh;
int item_amount = B_NR_ITEMS (bh = cur_bi->bi_bh);
if ( del_num == 0 )
return;
if ( first == 0 && del_num == item_amount && del_bytes == -1 ) {
make_empty_node (cur_bi);
mark_buffer_dirty (bh);
return;
}
if ( del_bytes == -1 )
/* delete del_num items beginning from item in position first */
leaf_delete_items_entirely (fs, cur_bi, first, del_num);
else {
if ( last_first == FIRST_TO_LAST ) {
/* delete del_num-1 items beginning from item in position first */
leaf_delete_items_entirely (fs, cur_bi, first, del_num-1);
/* delete the part of the first item of the bh do not
delete item header */
leaf_cut_from_buffer (fs, cur_bi, 0, 0, del_bytes);
} else {
struct item_head * ih;
int len;
/* delete del_num-1 items beginning from item in position first+1 */
leaf_delete_items_entirely (fs, cur_bi, first+1, del_num-1);
if (I_IS_DIRECTORY_ITEM(ih = B_N_PITEM_HEAD(bh, B_NR_ITEMS(bh)-1))) /* the last item is directory */
/* len = numbers of directory entries in this item */
len = get_ih_entry_count(ih);
else
/* len = body len of item */
len = get_ih_item_len (ih);
/* delete the part of the last item of the bh
do not delete item header
*/
leaf_cut_from_buffer (fs, cur_bi, B_NR_ITEMS(bh) - 1, len - del_bytes, del_bytes);
}
}
}
/* insert item into the leaf node in position before */
void leaf_insert_into_buf (reiserfs_filsys_t * s,
struct buffer_info * bi,
int before,
struct item_head * inserted_item_ih,
const char * inserted_item_body,
int zeros_number
)
{
struct buffer_head * bh = bi->bi_bh;
int nr;
struct block_head * blkh;
struct item_head * ih;
int i;
int last_loc, unmoved_loc;
char * to;
blkh = B_BLK_HEAD (bh);
nr = get_blkh_nr_items (blkh);
/* get item new item must be inserted before */
ih = B_N_PITEM_HEAD (bh, before);
/* prepare space for the body of new item */
last_loc = nr ? get_ih_location (&ih[nr - before - 1]) : bh->b_size;
unmoved_loc = before ? get_ih_location (ih-1) : bh->b_size;
memmove (bh->b_data + last_loc - get_ih_item_len (inserted_item_ih),
bh->b_data + last_loc, unmoved_loc - last_loc);
to = bh->b_data + unmoved_loc - get_ih_item_len (inserted_item_ih);
memset (to, 0, zeros_number);
to += zeros_number;
/* copy body to prepared space */
if (inserted_item_body)
//if (mem_mode == REISERFS_USER_MEM)
// copy_from_user (to, inserted_item_body, inserted_item_ih->ih_item_len - zeros_number);
//else {
memmove (to, inserted_item_body, get_ih_item_len (inserted_item_ih) - zeros_number);
//}
else
memset(to, '\0', get_ih_item_len (inserted_item_ih) - zeros_number);
/* insert item header */
memmove (ih + 1, ih, IH_SIZE * (nr - before));
memmove (ih, inserted_item_ih, IH_SIZE);
/* change locations */
for (i = before; i < nr + 1; i ++) {
unmoved_loc -= get_ih_item_len (&ih[i-before]);
set_ih_location (&ih[i-before], unmoved_loc);
}
/* sizes, free space, item number */
set_blkh_nr_items (blkh, get_blkh_nr_items (blkh) + 1);
set_blkh_free_space (blkh, get_blkh_free_space (blkh) -
(IH_SIZE + get_ih_item_len (inserted_item_ih)));
mark_buffer_dirty(bh) ;
if (bi->bi_parent) {
struct disk_child * dc;
dc = B_N_CHILD (bi->bi_parent, bi->bi_position);
set_dc_child_size (dc, get_dc_child_size (dc) + IH_SIZE + get_ih_item_len (inserted_item_ih));
mark_buffer_dirty(bi->bi_parent) ;
}
if (is_a_leaf(bh->b_data, bh->b_size) != THE_LEAF)
reiserfs_panic ("leaf_insert_into_buf: bad leaf %lu: %b", bh->b_blocknr, bh);
}
/* paste paste_size bytes to affected_item_num-th item.
When item is a directory, this only prepare space for new entries */
void leaf_paste_in_buffer (reiserfs_filsys_t * fs,
struct buffer_info * bi,
int affected_item_num,
int pos_in_item,
int paste_size,
const char * body,
int zeros_number)
{
struct buffer_head * bh = bi->bi_bh;
int nr;
struct block_head * blkh;
struct item_head * ih;
int i;
int last_loc, unmoved_loc;
blkh = B_BLK_HEAD (bh);
nr = get_blkh_nr_items (blkh);
/* item to be appended */
ih = B_N_PITEM_HEAD(bh, affected_item_num);
last_loc = get_ih_location (&ih[nr - affected_item_num - 1]);
unmoved_loc = affected_item_num ? get_ih_location (ih-1) : bh->b_size;
/* prepare space */
memmove (bh->b_data + last_loc - paste_size, bh->b_data + last_loc,
unmoved_loc - last_loc);
/* change locations */
for (i = affected_item_num; i < nr; i ++)
set_ih_location (&ih[i-affected_item_num], get_ih_location (&ih[i-affected_item_num]) - paste_size);
if ( body ) {
if (!I_IS_DIRECTORY_ITEM(ih)) {
//if (mem_mode == REISERFS_USER_MEM) {
//memset (bh->b_data + unmoved_loc - paste_size, 0, zeros_number);
//copy_from_user (bh->b_data + unmoved_loc - paste_size + zeros_number, body, paste_size - zeros_number);
//} else
{
if (!pos_in_item) {
/* shift data to right */
memmove (bh->b_data + get_ih_location (ih) + paste_size,
bh->b_data + get_ih_location (ih), get_ih_item_len (ih));
/* paste data in the head of item */
memset (bh->b_data + get_ih_location (ih), 0, zeros_number);
memcpy (bh->b_data + get_ih_location (ih) + zeros_number, body, paste_size - zeros_number);
} else {
memset (bh->b_data + unmoved_loc - paste_size, 0, zeros_number);
memcpy (bh->b_data + unmoved_loc - paste_size + zeros_number, body, paste_size - zeros_number);
}
}
}
}
else
memset(bh->b_data + unmoved_loc - paste_size,'\0',paste_size);
set_ih_item_len (ih, get_ih_item_len (ih) + paste_size);
/* change free space */
set_blkh_free_space (blkh, get_blkh_free_space (blkh) - paste_size);
mark_buffer_dirty(bh) ;
if (bi->bi_parent) {
struct disk_child * dc;
dc = B_N_CHILD (bi->bi_parent, bi->bi_position);
set_dc_child_size (dc, get_dc_child_size (dc) + paste_size);
mark_buffer_dirty(bi->bi_parent);
}
if (is_a_leaf(bh->b_data, bh->b_size) != THE_LEAF)
reiserfs_panic ("leaf_paste_in_buffer: bad leaf %lu: %b", bh->b_blocknr, bh);
}
/* cuts DEL_COUNT entries beginning from FROM-th entry. Directory item
does not have free space, so it moves DEHs and remaining records as
necessary. Return value is size of removed part of directory item
in bytes. */
static int leaf_cut_entries (struct buffer_head * bh,
struct item_head * ih,
int from, int del_count)
{
char * item;
struct reiserfs_de_head * deh;
int prev_record_offset; /* offset of record, that is (from-1)th */
char * prev_record; /* */
int cut_records_len; /* length of all removed records */
int i;
int entry_count;
/* first byte of item */
item = B_I_PITEM (bh, ih);
/* entry head array */
deh = B_I_DEH (bh, ih);
entry_count = get_ih_entry_count (ih);
if (del_count == 0) {
int shift;
int last_location;
last_location = get_deh_location (deh + entry_count - 1);
shift = last_location - DEH_SIZE * entry_count;
memmove (deh + entry_count, item + last_location,
get_ih_item_len (ih) - last_location);
for (i = 0; i < entry_count; i ++)
set_deh_location (&deh[i], get_deh_location (&deh[i]) - shift);
return shift;
}
/* first byte of remaining entries, those are BEFORE cut entries
(prev_record) and length of all removed records (cut_records_len) */
prev_record_offset = (from ? get_deh_location (&deh[from - 1]) : get_ih_item_len (ih));
cut_records_len = prev_record_offset/*from_record*/ - get_deh_location (&deh[from + del_count - 1]);
prev_record = item + prev_record_offset;
/* adjust locations of remaining entries */
for (i = get_ih_entry_count (ih) - 1; i > from + del_count - 1; i --) {
set_deh_location (deh + i, get_deh_location (deh + i) - (DEH_SIZE * del_count));
}
for (i = 0; i < from; i ++) {
set_deh_location (deh + i, get_deh_location (deh + i) - (DEH_SIZE * del_count + cut_records_len));
}
set_ih_entry_count (ih, get_ih_entry_count (ih) - del_count);
/* shift entry head array and entries those are AFTER removed entries */
memmove ((char *)(deh + from),
deh + from + del_count,
prev_record - cut_records_len - (char *)(deh + from + del_count));
/* shift records, those are BEFORE removed entries */
memmove (prev_record - cut_records_len - DEH_SIZE * del_count,
prev_record, item + get_ih_item_len (ih) - prev_record);
return DEH_SIZE * del_count + cut_records_len;
}
/* when cut item is part of regular file
pos_in_item - first byte that must be cut
cut_size - number of bytes to be cut beginning from pos_in_item
when cut item is part of directory
pos_in_item - number of first deleted entry
cut_size - count of deleted entries
*/
void leaf_cut_from_buffer (reiserfs_filsys_t * fs,
struct buffer_info * bi, int cut_item_num,
int pos_in_item, int cut_size)
{
int nr;
struct buffer_head * bh = bi->bi_bh;
struct block_head * blkh;
struct item_head * ih;
int last_loc, unmoved_loc;
int i;
blkh = B_BLK_HEAD (bh);
nr = get_blkh_nr_items (blkh);
/* item head of truncated item */
ih = B_N_PITEM_HEAD (bh, cut_item_num);
if (I_IS_DIRECTORY_ITEM (ih)) {
/* first cut entry ()*/
cut_size = leaf_cut_entries (bh, ih, pos_in_item, cut_size);
if (pos_in_item == 0) {
/* change item key by key of first entry in the item */
set_key_offset_v1 (&ih->ih_key, get_deh_offset (B_I_DEH (bh, ih)));
/*memcpy (&ih->ih_key.k_offset, &(B_I_DEH (bh, ih)->deh_offset), SHORT_KEY_SIZE);*/
}
} else {
/* item is direct or indirect */
/* shift item body to left if cut is from the head of item */
if (pos_in_item == 0) {
memmove (bh->b_data + get_ih_location (ih),
bh->b_data + get_ih_location (ih) + cut_size,
get_ih_item_len (ih) - cut_size);
/* change key of item */
if (I_IS_DIRECT_ITEM(ih)) {
//ih->ih_key.k_offset += cut_size;
set_offset (key_format (&ih->ih_key), &ih->ih_key, get_offset (&ih->ih_key) + cut_size);
} else {
//ih->ih_key.k_offset += (cut_size / UNFM_P_SIZE) * bh->b_size;
set_offset (key_format (&ih->ih_key), &ih->ih_key,
get_offset (&ih->ih_key) + (cut_size / UNFM_P_SIZE) * bh->b_size);
}
}
}
/* location of the last item */
last_loc = get_ih_location (&ih[nr - cut_item_num - 1]);
/* location of the item, which is remaining at the same place */
unmoved_loc = cut_item_num ? get_ih_location (ih-1) : bh->b_size;
/* shift */
memmove (bh->b_data + last_loc + cut_size, bh->b_data + last_loc,
unmoved_loc - last_loc - cut_size);
/* change item length */
set_ih_item_len (ih, get_ih_item_len (ih) - cut_size);
if (I_IS_INDIRECT_ITEM(ih)) {
if (pos_in_item)
//ih->u.ih_free_space = 0;
set_ih_free_space (ih, 0);
}
/* change locations */
for (i = cut_item_num; i < nr; i ++) {
set_ih_location (&ih[i-cut_item_num], get_ih_location (&ih[i-cut_item_num]) + cut_size);
}
/* size, free space */
set_blkh_free_space (blkh, get_blkh_free_space (blkh) + cut_size);
mark_buffer_dirty(bh);
if (bi->bi_parent) {
struct disk_child * dc;
dc = B_N_CHILD (bi->bi_parent, bi->bi_position);
set_dc_child_size (dc, get_dc_child_size (dc) - cut_size);
mark_buffer_dirty(bi->bi_parent);
}
if (is_a_leaf(bh->b_data, bh->b_size) != THE_LEAF)
reiserfs_panic ("leaf_cut_from_buffer: bad leaf %lu: %b",
bh->b_blocknr, bh);
}
/* delete del_num items from buffer starting from the first'th item */
static void leaf_delete_items_entirely (reiserfs_filsys_t * fs,
struct buffer_info * bi,
int first, int del_num)
{
struct buffer_head * bh = bi->bi_bh;
int nr;
int i, j;
int last_loc, last_removed_loc;
struct block_head * blkh;
struct item_head * ih;
if (del_num == 0)
return;
blkh = B_BLK_HEAD (bh);
nr = get_blkh_nr_items (blkh);
if (first == 0 && del_num == nr) {
/* this does not work */
make_empty_node (bi);
mark_buffer_dirty(bh);
return;
}
ih = B_N_PITEM_HEAD (bh, first);
/* location of unmovable item */
j = (first == 0) ? bh->b_size : get_ih_location (ih-1);
/* delete items */
last_loc = get_ih_location (&ih[nr - 1 - first]);
last_removed_loc = get_ih_location (&ih[del_num-1]);
memmove (bh->b_data + last_loc + j - last_removed_loc,
bh->b_data + last_loc, last_removed_loc - last_loc);
/* delete item headers */
memmove (ih, ih + del_num, (nr - first - del_num) * IH_SIZE);
/* change item location */
for (i = first; i < nr - del_num; i ++) {
set_ih_location (&ih[i-first], get_ih_location (&ih[i-first]) + j - last_removed_loc);
}
/* sizes, item number */
set_blkh_nr_items (blkh, get_blkh_nr_items (blkh)/*nr*/ - del_num);
set_blkh_free_space (blkh, get_blkh_free_space (blkh) + j - last_removed_loc + IH_SIZE * del_num);
mark_buffer_dirty(bh);
if (bi->bi_parent) {
struct disk_child * dc;
dc = B_N_CHILD (bi->bi_parent, bi->bi_position);
set_dc_child_size (dc, get_dc_child_size (dc) -
(j - last_removed_loc + IH_SIZE * del_num));
mark_buffer_dirty(bi->bi_parent);
}
if (is_a_leaf(bh->b_data, bh->b_size) != THE_LEAF)
reiserfs_panic ("leaf_delete_items_entirely: bad leaf %lu: %b", bh->b_blocknr, bh);
}
/* paste new_entry_count entries (new_dehs, records) into position before to item_num-th item */
void leaf_paste_entries (struct buffer_head * bh,
int item_num, int before, int new_entry_count,
struct reiserfs_de_head * new_dehs,
const char * records, int paste_size)
{
struct item_head * ih;
char * item;
struct reiserfs_de_head * deh;
char * insert_point;
int i, old_entry_num;
if (new_entry_count == 0)
return;
ih = B_N_PITEM_HEAD(bh, item_num);
/* first byte of dest item */
item = B_I_PITEM (bh, ih);
/* entry head array */
deh = B_I_DEH (bh, ih);
/* new records will be pasted at this point */
insert_point = item + (before ? get_deh_location (&deh[before - 1]) : (get_ih_item_len (ih) - paste_size));
/* adjust locations of records that will be AFTER new records */
for (i = get_ih_entry_count (ih) - 1; i >= before; i --)
set_deh_location (deh + i, get_deh_location (deh + i) + DEH_SIZE * new_entry_count);
/* adjust locations of records that will be BEFORE new records */
for (i = 0; i < before; i ++)
set_deh_location (deh + i, get_deh_location (deh + i) + paste_size);
old_entry_num = get_ih_entry_count (ih);
//I_ENTRY_COUNT(ih) += new_entry_count;
set_ih_entry_count (ih, old_entry_num + new_entry_count);
/* prepare space for pasted records */
memmove (insert_point + paste_size, insert_point, item + (get_ih_item_len (ih) - paste_size) - insert_point);
/* copy new records */
memcpy (insert_point + DEH_SIZE * new_entry_count, records,
paste_size - DEH_SIZE * new_entry_count);
/* prepare space for new entry heads */
deh += before;
memmove ((char *)(deh + new_entry_count), deh, insert_point - (char *)deh);
/* copy new entry heads */
memcpy (deh, new_dehs, DEH_SIZE * new_entry_count);
/* set locations of new records */
for (i = 0; i < new_entry_count; i ++)
set_deh_location (deh + i,
get_deh_location (deh + i) + (- get_deh_location (&new_dehs[new_entry_count - 1]) +
insert_point + DEH_SIZE * new_entry_count - item));
/* change item key if neccessary (when we paste before 0-th entry */
if (!before)
set_key_offset_v1 (&ih->ih_key, get_deh_offset (new_dehs));
}
/* wrappers for operations on one separated node */
void delete_item (reiserfs_filsys_t * fs,
struct buffer_head * bh, int item_num)
{
struct buffer_info bi;
bi.bi_bh = bh;
bi.bi_parent = 0;
bi.bi_position = 0;
leaf_delete_items_entirely (fs, &bi, item_num, 1);
}
void cut_entry (reiserfs_filsys_t * fs, struct buffer_head * bh,
int item_num, int entry_num, int del_count)
{
struct buffer_info bi;
bi.bi_bh = bh;
bi.bi_parent = 0;
bi.bi_position = 0;
leaf_cut_from_buffer (fs, &bi, item_num, entry_num, del_count);
}
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