401 lines
8.4 KiB
C
401 lines
8.4 KiB
C
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/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <assert.h>
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#include <errno.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include "backed_block.h"
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#include "sparse_defs.h"
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struct backed_block {
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unsigned int block;
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unsigned int len;
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enum backed_block_type type;
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union {
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struct {
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void *data;
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} data;
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struct {
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char *filename;
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int64_t offset;
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} file;
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struct {
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int fd;
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int64_t offset;
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} fd;
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struct {
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uint32_t val;
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} fill;
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};
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struct backed_block *next;
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};
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struct backed_block_list {
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struct backed_block *data_blocks;
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struct backed_block *last_used;
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unsigned int block_size;
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};
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struct backed_block *backed_block_iter_new(struct backed_block_list *bbl)
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{
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return bbl->data_blocks;
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}
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struct backed_block *backed_block_iter_next(struct backed_block *bb)
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{
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return bb->next;
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}
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unsigned int backed_block_len(struct backed_block *bb)
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{
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return bb->len;
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}
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unsigned int backed_block_block(struct backed_block *bb)
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{
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return bb->block;
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}
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void *backed_block_data(struct backed_block *bb)
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{
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assert(bb->type == BACKED_BLOCK_DATA);
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return bb->data.data;
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}
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const char *backed_block_filename(struct backed_block *bb)
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{
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assert(bb->type == BACKED_BLOCK_FILE);
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return bb->file.filename;
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}
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int backed_block_fd(struct backed_block *bb)
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{
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assert(bb->type == BACKED_BLOCK_FD);
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return bb->fd.fd;
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}
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int64_t backed_block_file_offset(struct backed_block *bb)
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{
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assert(bb->type == BACKED_BLOCK_FILE || bb->type == BACKED_BLOCK_FD);
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if (bb->type == BACKED_BLOCK_FILE) {
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return bb->file.offset;
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} else { /* bb->type == BACKED_BLOCK_FD */
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return bb->fd.offset;
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}
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}
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uint32_t backed_block_fill_val(struct backed_block *bb)
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{
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assert(bb->type == BACKED_BLOCK_FILL);
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return bb->fill.val;
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}
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enum backed_block_type backed_block_type(struct backed_block *bb)
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{
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return bb->type;
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}
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void backed_block_destroy(struct backed_block *bb)
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{
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if (bb->type == BACKED_BLOCK_FILE) {
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free(bb->file.filename);
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}
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free(bb);
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}
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struct backed_block_list *backed_block_list_new(unsigned int block_size)
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{
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struct backed_block_list *b = calloc(sizeof(struct backed_block_list), 1);
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b->block_size = block_size;
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return b;
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}
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void backed_block_list_destroy(struct backed_block_list *bbl)
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{
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if (bbl->data_blocks) {
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struct backed_block *bb = bbl->data_blocks;
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while (bb) {
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struct backed_block *next = bb->next;
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backed_block_destroy(bb);
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bb = next;
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}
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}
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free(bbl);
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}
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void backed_block_list_move(struct backed_block_list *from,
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struct backed_block_list *to, struct backed_block *start,
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struct backed_block *end)
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{
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struct backed_block *bb;
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if (start == NULL) {
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start = from->data_blocks;
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}
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if (!end) {
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for (end = start; end && end->next; end = end->next)
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;
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}
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if (start == NULL || end == NULL) {
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return;
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}
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from->last_used = NULL;
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to->last_used = NULL;
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if (from->data_blocks == start) {
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from->data_blocks = end->next;
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} else {
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for (bb = from->data_blocks; bb; bb = bb->next) {
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if (bb->next == start) {
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bb->next = end->next;
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break;
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}
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}
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}
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if (!to->data_blocks) {
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to->data_blocks = start;
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end->next = NULL;
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} else {
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for (bb = to->data_blocks; bb; bb = bb->next) {
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if (!bb->next || bb->next->block > start->block) {
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end->next = bb->next;
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bb->next = start;
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break;
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}
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}
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}
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}
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/* may free b */
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static int merge_bb(struct backed_block_list *bbl,
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struct backed_block *a, struct backed_block *b)
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{
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unsigned int block_len;
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/* Block doesn't exist (possible if one block is the last block) */
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if (!a || !b) {
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return -EINVAL;
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}
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assert(a->block < b->block);
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/* Blocks are of different types */
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if (a->type != b->type) {
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return -EINVAL;
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}
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/* Blocks are not adjacent */
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block_len = a->len / bbl->block_size; /* rounds down */
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if (a->block + block_len != b->block) {
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return -EINVAL;
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}
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switch (a->type) {
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case BACKED_BLOCK_DATA:
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/* Don't support merging data for now */
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return -EINVAL;
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case BACKED_BLOCK_FILL:
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if (a->fill.val != b->fill.val) {
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return -EINVAL;
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}
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break;
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case BACKED_BLOCK_FILE:
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if (a->file.filename != b->file.filename ||
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a->file.offset + a->len != b->file.offset) {
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return -EINVAL;
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}
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break;
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case BACKED_BLOCK_FD:
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if (a->fd.fd != b->fd.fd ||
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a->fd.offset + a->len != b->fd.offset) {
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return -EINVAL;
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}
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break;
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}
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/* Blocks are compatible and adjacent, with a before b. Merge b into a,
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* and free b */
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a->len += b->len;
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a->next = b->next;
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backed_block_destroy(b);
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return 0;
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}
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static int queue_bb(struct backed_block_list *bbl, struct backed_block *new_bb)
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{
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struct backed_block *bb;
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if (bbl->data_blocks == NULL) {
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bbl->data_blocks = new_bb;
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return 0;
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}
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if (bbl->data_blocks->block > new_bb->block) {
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new_bb->next = bbl->data_blocks;
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bbl->data_blocks = new_bb;
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return 0;
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}
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/* Optimization: blocks are mostly queued in sequence, so save the
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pointer to the last bb that was added, and start searching from
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there if the next block number is higher */
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if (bbl->last_used && new_bb->block > bbl->last_used->block)
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bb = bbl->last_used;
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else
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bb = bbl->data_blocks;
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bbl->last_used = new_bb;
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for (; bb->next && bb->next->block < new_bb->block; bb = bb->next)
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;
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if (bb->next == NULL) {
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bb->next = new_bb;
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} else {
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new_bb->next = bb->next;
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bb->next = new_bb;
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}
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merge_bb(bbl, new_bb, new_bb->next);
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merge_bb(bbl, bb, new_bb);
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return 0;
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}
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/* Queues a fill block of memory to be written to the specified data blocks */
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int backed_block_add_fill(struct backed_block_list *bbl, unsigned int fill_val,
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unsigned int len, unsigned int block)
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{
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struct backed_block *bb = calloc(1, sizeof(struct backed_block));
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if (bb == NULL) {
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return -ENOMEM;
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}
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bb->block = block;
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bb->len = len;
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bb->type = BACKED_BLOCK_FILL;
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bb->fill.val = fill_val;
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bb->next = NULL;
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return queue_bb(bbl, bb);
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}
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/* Queues a block of memory to be written to the specified data blocks */
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int backed_block_add_data(struct backed_block_list *bbl, void *data,
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unsigned int len, unsigned int block)
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{
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struct backed_block *bb = calloc(1, sizeof(struct backed_block));
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if (bb == NULL) {
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return -ENOMEM;
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}
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bb->block = block;
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bb->len = len;
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bb->type = BACKED_BLOCK_DATA;
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bb->data.data = data;
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bb->next = NULL;
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return queue_bb(bbl, bb);
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}
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/* Queues a chunk of a file on disk to be written to the specified data blocks */
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int backed_block_add_file(struct backed_block_list *bbl, const char *filename,
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int64_t offset, unsigned int len, unsigned int block)
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{
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struct backed_block *bb = calloc(1, sizeof(struct backed_block));
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if (bb == NULL) {
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return -ENOMEM;
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}
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bb->block = block;
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bb->len = len;
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bb->type = BACKED_BLOCK_FILE;
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bb->file.filename = strdup(filename);
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bb->file.offset = offset;
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bb->next = NULL;
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return queue_bb(bbl, bb);
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}
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/* Queues a chunk of a fd to be written to the specified data blocks */
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int backed_block_add_fd(struct backed_block_list *bbl, int fd, int64_t offset,
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unsigned int len, unsigned int block)
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{
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struct backed_block *bb = calloc(1, sizeof(struct backed_block));
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if (bb == NULL) {
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return -ENOMEM;
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}
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bb->block = block;
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bb->len = len;
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bb->type = BACKED_BLOCK_FD;
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bb->fd.fd = fd;
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bb->fd.offset = offset;
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bb->next = NULL;
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return queue_bb(bbl, bb);
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}
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int backed_block_split(struct backed_block_list *bbl, struct backed_block *bb,
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unsigned int max_len)
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{
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struct backed_block *new_bb;
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max_len = ALIGN_DOWN(max_len, bbl->block_size);
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if (bb->len <= max_len) {
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return 0;
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}
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new_bb = malloc(sizeof(struct backed_block));
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if (bb == NULL) {
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return -ENOMEM;
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}
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*new_bb = *bb;
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new_bb->len = bb->len - max_len;
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new_bb->block = bb->block + max_len / bbl->block_size;
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new_bb->next = bb->next;
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bb->next = new_bb;
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bb->len = max_len;
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switch (bb->type) {
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case BACKED_BLOCK_DATA:
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new_bb->data.data = (char *)bb->data.data + max_len;
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break;
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case BACKED_BLOCK_FILE:
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new_bb->file.offset += max_len;
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break;
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case BACKED_BLOCK_FD:
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new_bb->fd.offset += max_len;
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break;
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case BACKED_BLOCK_FILL:
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break;
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}
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return 0;
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}
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