osd-contiki/core/cfs/cfs-coffee.c

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/*
* Copyright (c) 2008, 2009, Swedish Institute of Computer Science
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* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
*/
/**
* \file
* Coffee: A flash file system for memory-constrained sensor systems.
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* \author
* Nicolas Tsiftes <nvt@sics.se>
*/
#include <contiki-conf.h>
#include <cfs/cfs.h>
#include <cfs-coffee-arch.h>
#include <cfs/cfs-coffee.h>
#include <dev/watchdog.h>
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#include <limits.h>
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#include <string.h>
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#define DEBUG 0
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#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
#if COFFEE_PAGES_PER_SECTOR & (COFFEE_PAGES_PER_SECTOR - 1)
#error COFFEE_PAGES_PER_SECTOR must be a power of two.
#error Change COFFEE_PAGES_PER_SECTOR in cfs-coffee-arch.h.
#endif
#define COFFEE_FD_FREE 0x0
#define COFFEE_FD_READ 0x1
#define COFFEE_FD_WRITE 0x2
#define COFFEE_FD_APPEND 0x4
#define COFFEE_FILE_MODIFIED 0x1
#define INVALID_PAGE ((coffee_page_t)-1)
#define UNKNOWN_OFFSET ((coffee_offset_t)-1)
#define FD_VALID(fd) \
((fd) >= 0 && (fd) < COFFEE_FD_SET_SIZE && \
coffee_fd_set[(fd)].flags != COFFEE_FD_FREE)
#define FD_READABLE(fd) (coffee_fd_set[(fd)].flags & CFS_READ)
#define FD_WRITABLE(fd) (coffee_fd_set[(fd)].flags & CFS_WRITE)
#define FD_APPENDABLE(fd) (coffee_fd_set[(fd)].flags & CFS_APPEND)
#define FILE_MODIFIED(file) ((file)->flags & COFFEE_FILE_MODIFIED)
/* File header flags. */
#define HDR_FLAG_VALID 0x1 /* Completely written header. */
#define HDR_FLAG_ALLOCATED 0x2 /* Allocated file. */
#define HDR_FLAG_OBSOLETE 0x4 /* File marked for GC. */
#define HDR_FLAG_MODIFIED 0x8 /* Modified file, log exists. */
#define HDR_FLAG_LOG 0x10 /* Log file. */
#define HDR_FLAG_ISOLATED 0x20 /* Isolated page. */
#define CHECK_FLAG(hdr, flag) ((hdr).flags & (flag))
#define HDR_VALID(hdr) CHECK_FLAG(hdr, HDR_FLAG_VALID)
#define HDR_ALLOCATED(hdr) CHECK_FLAG(hdr, HDR_FLAG_ALLOCATED)
#define HDR_FREE(hdr) !HDR_ALLOCATED(hdr)
#define HDR_LOG(hdr) CHECK_FLAG(hdr, HDR_FLAG_LOG)
#define HDR_MODIFIED(hdr) CHECK_FLAG(hdr, HDR_FLAG_MODIFIED)
#define HDR_ISOLATED(hdr) CHECK_FLAG(hdr, HDR_FLAG_ISOLATED)
#define HDR_OBSOLETE(hdr) CHECK_FLAG(hdr, HDR_FLAG_OBSOLETE)
#define HDR_ACTIVE(hdr) (HDR_ALLOCATED(hdr) && \
!HDR_OBSOLETE(hdr) && \
!HDR_ISOLATED(hdr))
#define COFFEE_SECTOR_COUNT (COFFEE_SIZE / COFFEE_SECTOR_SIZE)
#define COFFEE_PAGE_COUNT \
((coffee_page_t)(COFFEE_SIZE / COFFEE_PAGE_SIZE))
#define COFFEE_PAGES_PER_SECTOR \
((coffee_page_t)(COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE))
struct sector_stats {
coffee_page_t active;
coffee_page_t obsolete;
coffee_page_t free;
};
struct file {
coffee_offset_t end;
coffee_page_t page;
coffee_page_t max_pages;
int16_t next_log_record;
uint8_t references;
uint8_t flags;
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};
struct file_desc {
coffee_offset_t offset;
struct file *file;
uint8_t flags;
};
struct file_header {
coffee_page_t log_page;
uint16_t log_records;
uint16_t log_record_size;
coffee_page_t max_pages;
uint8_t eof_hint;
uint8_t flags;
char name[COFFEE_NAME_LENGTH];
} __attribute__((packed));
/* This is needed because of a buggy compiler. */
struct log_param {
coffee_offset_t offset;
const char *buf;
uint16_t size;
};
static struct protected_mem_t {
struct file coffee_files[COFFEE_MAX_OPEN_FILES];
struct file_desc coffee_fd_set[COFFEE_FD_SET_SIZE];
} protected_mem;
static struct file *coffee_files = protected_mem.coffee_files;
static struct file_desc *coffee_fd_set = protected_mem.coffee_fd_set;
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/*---------------------------------------------------------------------------*/
static void
write_header(struct file_header *hdr, coffee_page_t page)
{
hdr->flags |= HDR_FLAG_VALID;
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COFFEE_WRITE(hdr, sizeof(*hdr), page * COFFEE_PAGE_SIZE);
}
/*---------------------------------------------------------------------------*/
static void
read_header(struct file_header *hdr, coffee_page_t page)
{
COFFEE_READ(hdr, sizeof(*hdr), page * COFFEE_PAGE_SIZE);
#if DEBUG
if(HDR_ACTIVE(*hdr) && !HDR_VALID(*hdr)) {
PRINTF("Invalid header at page %u!\n", (unsigned)page);
}
#endif
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}
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/*---------------------------------------------------------------------------*/
static coffee_offset_t
absolute_offset(coffee_page_t page, coffee_offset_t offset)
{
return page * COFFEE_PAGE_SIZE + sizeof(struct file_header) + offset;
}
/*---------------------------------------------------------------------------*/
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static void
get_sector_status(uint16_t sector, struct sector_stats *stats) {
static coffee_page_t skip_pages, active, obsolete, free;
static char last_pages_are_active;
coffee_offset_t offset, sector_start, end;
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struct file_header hdr;
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coffee_page_t jump;
int i;
active = obsolete = free = 0;
if(sector == 0) {
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skip_pages = 0;
last_pages_are_active = 0;
} else if(skip_pages > COFFEE_PAGES_PER_SECTOR) {
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skip_pages -= COFFEE_PAGES_PER_SECTOR;
if(last_pages_are_active) {
active = COFFEE_PAGES_PER_SECTOR;
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} else {
obsolete = COFFEE_PAGES_PER_SECTOR;
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}
return;
}
sector_start = sector * COFFEE_SECTOR_SIZE;
if(last_pages_are_active) {
active = skip_pages;
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} else {
obsolete = skip_pages;
/* Split an obsolete file starting in the previous sector and mark
the following pages as isolated. */
offset = sector_start;
for(i = 0; i < skip_pages; i++) {
COFFEE_READ(&hdr, sizeof(hdr), offset);
hdr.flags |= HDR_FLAG_ALLOCATED | HDR_FLAG_ISOLATED;
COFFEE_WRITE(&hdr, sizeof(hdr), offset);
offset += COFFEE_PAGE_SIZE;
}
PRINTF("Coffee: Isolated %u pages starting in sector %d\n",
(unsigned)skip_pages, (int)sector);
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}
offset = sector_start + (skip_pages * COFFEE_PAGE_SIZE);
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end = (sector + 1) * COFFEE_SECTOR_SIZE;
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jump = 0;
while(offset < end) {
COFFEE_READ(&hdr, sizeof(hdr), offset);
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last_pages_are_active = 0;
if(HDR_ACTIVE(hdr)) {
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last_pages_are_active = 1;
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jump = hdr.max_pages;
active += jump;
} else if(HDR_ISOLATED(hdr)) {
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jump = 1;
obsolete++;
} else if(HDR_OBSOLETE(hdr)) {
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jump = hdr.max_pages;
obsolete += jump;
} else {
free = COFFEE_PAGES_PER_SECTOR - active - obsolete;
break;
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}
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offset += jump * COFFEE_PAGE_SIZE;
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}
skip_pages = active + obsolete + free - COFFEE_PAGES_PER_SECTOR;
if(skip_pages > 0) {
if(last_pages_are_active) {
active = COFFEE_PAGES_PER_SECTOR - obsolete;
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} else {
obsolete = COFFEE_PAGES_PER_SECTOR - active;
}
}
stats->active = active;
stats->obsolete = obsolete;
stats->free = free;
}
/*---------------------------------------------------------------------------*/
static void
cfs_garbage_collect(void)
{
uint16_t sector;
struct sector_stats stats;
watchdog_stop();
PRINTF("Coffee: Running the file system garbage collector...\n");
/*
* The garbage collector erases as many sectors as possible. A sector is
* erasable if there are only free or obsolete pages in it.
*/
for(sector = 0; sector < COFFEE_SECTOR_COUNT; sector++) {
get_sector_status(sector, &stats);
PRINTF("Coffee: Sector %u has %u active, %u free, and %u obsolete pages.\n",
sector, (unsigned)stats.active, (unsigned)stats.free, (unsigned)stats.obsolete);
if(stats.active == 0 && stats.obsolete > 0) {
COFFEE_ERASE(sector);
PRINTF("Coffee: Erased sector %d!\n", sector);
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}
}
watchdog_start();
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}
/*---------------------------------------------------------------------------*/
static struct file *
load_file(const char *name, struct file_header *hdr, coffee_page_t start)
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{
int i, unreferenced, free;
struct file *file;
for(i = 0, unreferenced = free = -1; i < COFFEE_MAX_OPEN_FILES; i++) {
if(coffee_files[i].page == INVALID_PAGE) {
free = i;
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break;
} else if(coffee_files[i].references == 0) {
unreferenced = i;
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}
}
if(free != -1) {
i = free;
} else if(unreferenced != -1) {
i = unreferenced;
} else {
return NULL;
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}
file = &coffee_files[i];
file->page = start;
file->end = UNKNOWN_OFFSET;
file->max_pages = hdr->max_pages;
file->next_log_record = -1;
return file;
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}
/*---------------------------------------------------------------------------*/
static struct file *
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find_file(const char *name)
{
int i;
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struct file_header hdr;
coffee_page_t page;
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/* First check if the file metadata is cached. */
for(i = 0; i < COFFEE_MAX_OPEN_FILES; i++) {
if(coffee_files[i].max_pages == 0) {
continue;
}
read_header(&hdr, coffee_files[i].page);
if(HDR_ACTIVE(hdr) && strcmp(name, hdr.name) == 0) {
return &coffee_files[i];
}
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}
/* Scan the flash memory sequentially otherwise. */
page = 0;
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do {
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read_header(&hdr, page);
if(HDR_ACTIVE(hdr)) {
if(strcmp(name, hdr.name) == 0) {
return load_file(name, &hdr, page);
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}
page += hdr.max_pages;
} else if(HDR_ISOLATED(hdr)) {
++page;
} else if(HDR_OBSOLETE(hdr)) {
page += hdr.max_pages;
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} else {
/* It follows from the properties of the page allocation algorithm
that if a free page is encountered, then the rest of the sector
is also free. */
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
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}
watchdog_periodic();
} while(page < COFFEE_PAGE_COUNT);
return NULL;
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}
/*---------------------------------------------------------------------------*/
static void
refresh_eof_hint(struct file *file)
{
struct file_header hdr;
coffee_page_t current_page;
int part_size, i;
uint8_t eof_hint;
read_header(&hdr, file->page);
current_page = (file->end + sizeof(hdr)) / COFFEE_PAGE_SIZE;
part_size = hdr.max_pages / (sizeof(hdr.eof_hint) * CHAR_BIT);
if(part_size == 0) {
part_size = 1;
}
for(i = eof_hint = 0; i < sizeof(eof_hint) * CHAR_BIT; i++) {
eof_hint |= (current_page >= (i + 1) * part_size) << i;
}
if(eof_hint > hdr.eof_hint) {
hdr.eof_hint |= eof_hint;
write_header(&hdr, file->page);
}
}
/*---------------------------------------------------------------------------*/
static coffee_offset_t
file_end(coffee_page_t start)
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{
struct file_header hdr;
unsigned char buf[COFFEE_PAGE_SIZE];
coffee_page_t page;
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int i;
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int search_limit;
coffee_page_t range_start, range_end, part_size;
read_header(&hdr, start);
search_limit = 0;
for(i = 0; i < sizeof(hdr.eof_hint) * CHAR_BIT; i++) {
if(hdr.eof_hint >> i) {
search_limit = i + 1;
}
}
part_size = hdr.max_pages / sizeof(hdr.eof_hint) / CHAR_BIT;
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if(part_size == 0) {
part_size = 1;
}
range_start = part_size * search_limit;
range_end = range_start + part_size;
if(range_end + 1 > hdr.max_pages) {
range_end = hdr.max_pages - 1;
}
/*
* Move from the end of the range towards the beginning and look for
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* a byte that has been modified.
*
* An important implication of this is that if the last written bytes
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* are zeroes, then these are skipped from the calculation.
*/
for(page = start + range_end; page >= start; page--) {
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watchdog_periodic();
COFFEE_READ(buf, sizeof(buf), page * COFFEE_PAGE_SIZE);
for(i = COFFEE_PAGE_SIZE - 1; i >= 0; i--) {
if(buf[i] != 0) {
if(page == start && i < sizeof(hdr)) {
return 0;
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}
return 1 + i + ((page - start) * COFFEE_PAGE_SIZE) - sizeof(hdr);
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}
}
}
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/* All bytes are writable. */
return 0;
}
/*---------------------------------------------------------------------------*/
static coffee_page_t
find_contiguous_pages(coffee_page_t amount)
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{
coffee_page_t page, start;
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struct file_header hdr;
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start = -1;
for(page = 0; page < COFFEE_PAGE_COUNT;) {
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read_header(&hdr, page);
if(HDR_FREE(hdr)) {
if(start == -1) {
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start = page;
}
/* Jump to the next sector. */
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
if(start + amount <= page) {
return start;
}
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} else {
start = -1;
page += HDR_ISOLATED(hdr) ? 1 : hdr.max_pages;
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}
}
return -1;
}
/*---------------------------------------------------------------------------*/
static int
remove_by_page(coffee_page_t page, int remove_log, int close_fds)
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{
struct file_header hdr;
int i, last_valid;
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read_header(&hdr, page);
if(!HDR_ACTIVE(hdr)) {
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return -1;
}
if(remove_log && HDR_MODIFIED(hdr)) {
if (remove_by_page(hdr.log_page, 0, 0) < 0) {
return -1;
}
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}
hdr.flags |= HDR_FLAG_OBSOLETE;
write_header(&hdr, page);
/* Close all file descriptors that reference the removed file. */
if(close_fds) {
last_valid = -1;
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
if(coffee_fd_set[i].file->page == page) {
coffee_fd_set[i].flags = COFFEE_FD_FREE;
last_valid = i;
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}
}
if(last_valid >= 0) {
coffee_fd_set[last_valid].file->page = INVALID_PAGE;
coffee_fd_set[last_valid].file->max_pages = 0;
coffee_fd_set[last_valid].file->references = 0;
}
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}
return 0;
}
/*---------------------------------------------------------------------------*/
static coffee_page_t
page_count(coffee_offset_t size)
{
return (size + sizeof(struct file_header) + COFFEE_PAGE_SIZE - 1) /
COFFEE_PAGE_SIZE;
}
/*---------------------------------------------------------------------------*/
static struct file *
reserve(const char *name, coffee_page_t pages, int allow_duplicates)
{
struct file_header hdr;
coffee_page_t page;
struct file *file;
watchdog_stop();
if(!allow_duplicates && find_file(name) != NULL) {
watchdog_start();
return NULL;
}
page = find_contiguous_pages(pages);
if(page == INVALID_PAGE) {
cfs_garbage_collect();
page = find_contiguous_pages(pages);
if(page == INVALID_PAGE) {
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watchdog_start();
return NULL;
}
}
memset(&hdr, 0, sizeof(hdr));
memcpy(hdr.name, name, sizeof(hdr.name) - 1);
hdr.name[sizeof(hdr.name) - 1] = '\0';
hdr.max_pages = pages;
hdr.flags = HDR_FLAG_ALLOCATED;
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write_header(&hdr, page);
PRINTF("Coffee: Reserved %u pages starting from %u for file %s\n",
pages, page, name);
file = load_file(name, &hdr, page);
file->end = 0;
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watchdog_start();
return file;
}
/*---------------------------------------------------------------------------*/
static void
adjust_log_config(struct file_header *hdr,
uint16_t *log_record_size, uint16_t *log_records)
{
*log_record_size = hdr->log_record_size == 0 ?
COFFEE_PAGE_SIZE : hdr->log_record_size;
*log_records = hdr->log_records == 0 ?
COFFEE_LOG_SIZE / *log_record_size : hdr->log_records;
}
/*---------------------------------------------------------------------------*/
static uint16_t
modify_log_buffer(uint16_t log_record_size,
coffee_offset_t *offset, uint16_t *size)
{
uint16_t region;
region = *offset / log_record_size;
*offset %= log_record_size;
if(*size > log_record_size - *offset) {
*size = log_record_size - *offset;
}
return region;
}
/*---------------------------------------------------------------------------*/
static int
get_record_index(coffee_page_t log_page, uint16_t search_records,
uint16_t region)
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{
coffee_offset_t base;
uint16_t processed;
uint16_t batch_size;
int16_t match_index, i;
uint16_t record_count;
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base = absolute_offset(log_page, sizeof(uint16_t) * search_records);
record_count = search_records > COFFEE_LOG_TABLE_LIMIT ?
COFFEE_LOG_TABLE_LIMIT : search_records;
processed = 0;
match_index = -1;
{
uint16_t indices[record_count];
while(processed < search_records && match_index < 0) {
if(record_count + processed > search_records) {
batch_size = search_records - processed;
} else {
batch_size = record_count;
}
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base -= batch_size * sizeof(indices[0]);
COFFEE_READ(&indices, sizeof(indices[0]) * batch_size, base);
for(i = batch_size - 1; i >= 0; i--) {
if(indices[i] - 1 == region) {
match_index = search_records - processed - (batch_size - i);
break;
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}
}
processed += batch_size;
}
}
return match_index;
}
/*---------------------------------------------------------------------------*/
static int
read_log_page(struct file_header *hdr, int16_t last_record, struct log_param *lp)
{
uint16_t region;
int16_t match_index;
uint16_t log_record_size;
uint16_t log_records;
coffee_offset_t base;
uint16_t search_records;
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adjust_log_config(hdr, &log_record_size, &log_records);
region = modify_log_buffer(log_record_size, &lp->offset, &lp->size);
search_records = last_record < 0 ? log_records : last_record + 1;
match_index = get_record_index(hdr->log_page, search_records, region);
if(match_index < 0) {
return -1;
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}
base = hdr->log_page * COFFEE_PAGE_SIZE;
base += sizeof(struct file_header) + log_records * sizeof(region);
base += (coffee_offset_t)match_index * log_record_size;
base += lp->offset;
COFFEE_READ(lp->buf, lp->size, base);
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return lp->size;
}
/*---------------------------------------------------------------------------*/
static unsigned char *
create_log_name(unsigned char *new, int max_size, unsigned char *old)
{
unsigned char suffix[] = ".log";
int len;
len = strlen(old);
if(len > max_size - sizeof(suffix)) {
len = max_size - sizeof(suffix);
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}
memcpy(new, old, len);
memcpy(&new[len], suffix, sizeof(suffix));
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return new;
}
/*---------------------------------------------------------------------------*/
static coffee_page_t
create_log(struct file *file, struct file_header *hdr)
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{
coffee_page_t log_page;
unsigned char log_name[sizeof(hdr->name)];
uint16_t log_record_size, log_records;
coffee_offset_t size;
struct file *log_file;
adjust_log_config(hdr, &log_record_size, &log_records);
size = log_records * sizeof(uint16_t); /* Log index size. */
size += log_records * log_record_size; /* Log data size. */
log_file = reserve(create_log_name(log_name, sizeof(log_name), hdr->name),
page_count(size), 0);
if(file == NULL) {
return INVALID_PAGE;
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}
log_page = log_file->page;
hdr->flags |= HDR_FLAG_MODIFIED;
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hdr->log_page = log_page;
write_header(hdr, file->page);
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read_header(hdr, log_page);
hdr->flags |= HDR_FLAG_LOG;
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write_header(hdr, log_page);
file->flags |= COFFEE_FILE_MODIFIED;
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return log_page;
}
/*---------------------------------------------------------------------------*/
static int
merge_log(coffee_page_t file_page, int extend)
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{
coffee_page_t log_page;
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struct file_header hdr, hdr2;
int fd, n;
coffee_offset_t offset;
coffee_page_t max_pages;
struct file *new_file;
int i;
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read_header(&hdr, file_page);
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log_page = hdr.log_page;
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fd = cfs_open(hdr.name, CFS_READ);
if(fd < 0) {
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return -1;
}
/*
* The reservation function adds extra space for the header, which has
* already been calculated with in the previous reservation.
*/
max_pages = hdr.max_pages << extend;
new_file = reserve(hdr.name, max_pages, 1);
if(new_file == NULL) {
cfs_close(fd);
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return -1;
}
offset = 0;
do {
char buf[hdr.log_record_size == 0 ? COFFEE_PAGE_SIZE : hdr.log_record_size];
watchdog_periodic();
n = cfs_read(fd, buf, sizeof(buf));
if(n < 0) {
remove_by_page(new_file->page, 0, 0);
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cfs_close(fd);
return -1;
} else if(n > 0) {
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COFFEE_WRITE(buf, n,
absolute_offset(new_file->page, offset));
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offset += n;
}
} while(n != 0);
if(remove_by_page(file_page, 1, 0) < 0) {
remove_by_page(new_file->page, 0, 0);
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cfs_close(fd);
return -1;
}
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/* Copy the log configuration and the EOF hint. */
read_header(&hdr2, new_file->page);
hdr2.log_record_size = hdr.log_record_size;
hdr2.log_records = hdr.log_records;
hdr2.eof_hint = extend ? 0 : hdr.eof_hint;
write_header(&hdr2, new_file->page);
if(extend) {
new_file->end = offset;
refresh_eof_hint(new_file);
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}
cfs_close(fd);
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
if(coffee_fd_set[i].flags != COFFEE_FD_FREE &&
coffee_fd_set[i].file->page == file_page) {
coffee_fd_set[i].file = new_file;
new_file->references++;
}
}
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return 0;
}
/*---------------------------------------------------------------------------*/
static int
find_next_record(struct file *file, coffee_page_t log_page,
int log_records)
{
int log_record, i, preferred_batch_size;
preferred_batch_size = log_records > COFFEE_LOG_TABLE_LIMIT ?
COFFEE_LOG_TABLE_LIMIT : log_records;
if(file->next_log_record == 0) {
/* The next log record is unknown. Search for it. */
uint16_t indices[preferred_batch_size];
uint16_t processed;
uint16_t batch_size;
log_record = log_records;
for(processed = 0; processed < log_records; processed += batch_size) {
batch_size = log_records - processed >= preferred_batch_size ?
preferred_batch_size : log_records - processed;
COFFEE_READ(&indices, batch_size * sizeof(indices[0]),
absolute_offset(log_page, processed * sizeof(indices[0])));
for(i = 0; i < batch_size && indices[i] != 0; i++);
log_record = i;
if(log_record < batch_size) {
log_record += processed;
break;
}
}
} else {
log_record = file->next_log_record;
}
return log_record;
}
/*---------------------------------------------------------------------------*/
static int
write_log_page(struct file *file, struct log_param *lp)
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{
struct file_header hdr;
uint16_t region;
coffee_page_t log_page;
int16_t log_record;
uint16_t log_record_size;
uint16_t log_records;
coffee_offset_t base;
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struct log_param lp_out;
read_header(&hdr, file->page);
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adjust_log_config(&hdr, &log_record_size, &log_records);
region = modify_log_buffer(log_record_size, &lp->offset, &lp->size);
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log_page = 0;
if(HDR_MODIFIED(hdr)) {
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/* A log structure has already been created. */
log_page = hdr.log_page;
log_record = find_next_record(file, log_page, log_records);
if(log_record >= log_records) {
/* The log is full; merge the log. */
PRINTF("Coffee: Merging the file %s with its log\n", hdr.name);
refresh_eof_hint(file);
return merge_log(file->page, 0);
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}
} else {
/* Create a log structure. */
log_page = create_log(file, &hdr);
if(log_page == INVALID_PAGE) {
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return -1;
}
PRINTF("Coffee: Created a log structure for file %s at page %u\n",
hdr.name, (unsigned)log_page);
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hdr.log_page = log_page;
log_record = 0;
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}
{
unsigned char copy_buf[log_record_size];
lp_out.offset = region * log_record_size;
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lp_out.buf = copy_buf;
lp_out.size = log_record_size;
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if((lp->offset > 0 || lp->size != log_record_size) &&
read_log_page(&hdr, file->next_log_record - 1, &lp_out) < 0) {
COFFEE_READ(copy_buf, sizeof(copy_buf),
absolute_offset(file->page, region * log_record_size));
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}
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memcpy((char *) &copy_buf + lp->offset, lp->buf, lp->size);
base = (coffee_offset_t)log_page * COFFEE_PAGE_SIZE;
base += sizeof(hdr);
base += log_records * sizeof(region);
base += (coffee_offset_t)log_record * log_record_size;
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COFFEE_WRITE(copy_buf, sizeof(copy_buf), base);
++region;
COFFEE_WRITE(&region, sizeof(region),
absolute_offset(log_page, log_record * sizeof(region)));
file->next_log_record = log_record + 1;
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}
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return lp->size;
}
/*---------------------------------------------------------------------------*/
static int
get_available_fd(void)
{
int i;
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
if(coffee_fd_set[i].flags == COFFEE_FD_FREE) {
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return i;
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
int
cfs_open(const char *name, int flags)
{
int fd;
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struct file_desc *fdp;
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fd = get_available_fd();
if(fd < 0) {
PRINTF("Coffee: Failed to allocate a new file descriptor!\n");
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return -1;
}
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fdp = &coffee_fd_set[fd];
fdp->flags = 0;
fdp->file = find_file(name);
if(fdp->file == NULL) {
if((flags & (CFS_READ | CFS_WRITE)) == CFS_READ) {
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return -1;
}
fdp->file = reserve(name, page_count(COFFEE_DYN_SIZE), 1);
if(fdp->file == NULL) {
return -1;
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}
fdp->file->end = 0;
} else if(fdp->file->end == UNKNOWN_OFFSET) {
fdp->file->end = file_end(fdp->file->page);
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}
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fdp->flags |= flags;
fdp->offset = flags & CFS_APPEND ? fdp->file->end : 0;
fdp->file->references++;
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return fd;
}
/*---------------------------------------------------------------------------*/
void
cfs_close(int fd)
{
if(FD_VALID(fd)) {
refresh_eof_hint(coffee_fd_set[fd].file);
coffee_fd_set[fd].flags = COFFEE_FD_FREE;
coffee_fd_set[fd].file->references--;
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}
}
/*---------------------------------------------------------------------------*/
unsigned
cfs_seek(int fd, unsigned offset)
{
struct file_header hdr;
struct file_desc *fdp;
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if(!FD_VALID(fd)) {
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return -1;
}
fdp = &coffee_fd_set[fd];
read_header(&hdr, fdp->file->page);
/* Check if the offset is within the file boundary. */
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if(sizeof(hdr) + offset >= hdr.max_pages * COFFEE_PAGE_SIZE ||
sizeof(hdr) + offset < offset) {
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return -1;
}
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if(fdp->file->end < offset) {
fdp->file->end = offset;
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}
return fdp->offset = offset;
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}
/*---------------------------------------------------------------------------*/
int
cfs_remove(const char *name)
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{
struct file *file;
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/*
* Coffee removes files by marking them as obsolete. The space
* is not guaranteed to be reclaimed immediately, but must be
* sweeped by the garbage collector. The garbage collector is
* called once a file reservation request cannot be granted.
*/
file = find_file(name);
if(file == NULL) {
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return -1;
}
return remove_by_page(file->page, 1, 1);
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}
/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_header hdr;
struct file_desc *fdp;
struct file *file;
unsigned remains, read_chunk;
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int r;
coffee_offset_t base, offset;
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struct log_param lp;
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
2008-04-28 12:33:14 +02:00
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
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}
read_chunk = COFFEE_PAGE_SIZE;
if(FILE_MODIFIED(file)) {
read_header(&hdr, file->page);
if(hdr.log_record_size > 0) {
read_chunk = hdr.log_record_size;
}
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}
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remains = size;
base = fdp->offset;
offset = 0;
/*
* Fill the buffer by copying from the log in first hand, or the
* ordinary file if the page has no log record.
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*/
while(remains) {
watchdog_periodic();
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r = -1;
if(FILE_MODIFIED(file)) {
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lp.offset = base + offset;
lp.buf = (char *)buf + offset;
lp.size = remains;
r = read_log_page(&hdr, file->next_log_record - 1, &lp);
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}
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
r = remains > read_chunk ? read_chunk : remains;
2008-04-28 12:33:14 +02:00
COFFEE_READ((char *) buf + offset, r,
absolute_offset(file->page, base + offset));
2008-04-28 12:33:14 +02:00
}
remains -= r;
offset += r;
}
fdp->offset += offset;
return offset;
}
/*---------------------------------------------------------------------------*/
int
cfs_write(int fd, const void *buf, unsigned size)
{
struct file_desc *fdp;
struct file *file;
2008-04-28 12:33:14 +02:00
int i;
struct log_param lp;
coffee_offset_t remains;
2008-11-13 01:58:51 +01:00
if(!(FD_VALID(fd) && FD_WRITABLE(fd))) {
2008-04-28 12:33:14 +02:00
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
/* Attempt to extend the file if we try to write past the end. */
while(size + fdp->offset + sizeof(struct file_header) >
(file->max_pages * COFFEE_PAGE_SIZE)) {
refresh_eof_hint(file);
if(merge_log(file->page, 1) < 0) {
return -1;
}
file = fdp->file;
PRINTF("Extended the file at page %u\n", (unsigned)file->page);
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}
if(fdp->offset < file->end) {
remains = size;
while(remains) {
lp.offset = fdp->offset;
lp.buf = (char *)buf + size - remains;
lp.size = remains;
i = write_log_page(file, &lp);
if(i == 0) {
file = fdp->file;
/* The file was merged with the log. Try again. */
2008-11-19 15:39:08 +01:00
continue;
}
if(i < 0) {
return size - remains > 0 ? size - remains : -1;
}
remains -= i;
fdp->offset += i;
2008-04-28 12:33:14 +02:00
}
} else {
COFFEE_WRITE(buf, size,
absolute_offset(file->page, fdp->offset));
fdp->offset += size;
2008-04-28 12:33:14 +02:00
}
if(fdp->offset > file->end) {
file->end = fdp->offset;
2008-04-28 12:33:14 +02:00
}
return size;
}
/*---------------------------------------------------------------------------*/
int
cfs_opendir(struct cfs_dir *dir, const char *name)
{
2008-04-28 12:33:14 +02:00
/* We have only a root directory. */
if(name[0] != '/' || name[1] != '\0') {
2008-04-28 12:33:14 +02:00
return -1;
}
*(coffee_page_t *)dir->dummy_space = 0;
2008-04-28 12:33:14 +02:00
return 0;
}
/*---------------------------------------------------------------------------*/
int
cfs_readdir(struct cfs_dir *dir, struct cfs_dirent *record)
2008-04-28 12:33:14 +02:00
{
struct file_header hdr;
coffee_page_t page;
for(page = *(coffee_page_t *)dir->dummy_space; page < COFFEE_PAGE_COUNT;) {
2008-04-28 12:33:14 +02:00
watchdog_periodic();
2008-11-04 18:48:36 +01:00
read_header(&hdr, page);
if(HDR_FREE(hdr)) {
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
} else if(HDR_ISOLATED(hdr)) {
++page;
} else if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr)) {
memcpy(record->name, hdr.name, sizeof(record->name));
record->name[sizeof(record->name) - 1] = '\0';
record->size = file_end(page);
page += hdr.max_pages;
*(coffee_page_t *)dir->dummy_space = page;
return 0;
} else {
page += hdr.max_pages;
2008-04-28 12:33:14 +02:00
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
void
cfs_closedir(struct cfs_dir *dir)
{
return;
}
/*---------------------------------------------------------------------------*/
int
cfs_coffee_reserve(const char *name, uint32_t size)
{
return reserve(name, page_count(size), 0) == NULL ? -1 : 0;
}
/*---------------------------------------------------------------------------*/
int
cfs_coffee_configure_log(const char *filename, unsigned log_size,
unsigned log_record_size)
2008-04-28 12:33:14 +02:00
{
struct file *file;
2008-04-28 12:33:14 +02:00
struct file_header hdr;
if(log_record_size == 0 || log_record_size > COFFEE_PAGE_SIZE ||
log_size < log_record_size) {
return -1;
}
file = find_file(filename);
if(file == NULL) {
2008-04-28 12:33:14 +02:00
return -1;
}
read_header(&hdr, file->page);
if(HDR_MODIFIED(hdr)) {
/* Too late to customize the log. */
2008-04-28 12:33:14 +02:00
return -1;
}
hdr.log_records = log_size / log_record_size;
hdr.log_record_size = log_record_size;
write_header(&hdr, file->page);
2008-04-28 12:33:14 +02:00
return 0;
}
/*---------------------------------------------------------------------------*/
int
cfs_coffee_format(void)
{
int nsectors, i;
nsectors = COFFEE_SECTOR_COUNT;
/* Reject format requests when the configuration is incorrect. */
if(nsectors < 1 || (COFFEE_START & (COFFEE_SECTOR_SIZE - 1))) {
return -1;
}
PRINTF("Coffee: Formatting %d sectors", nsectors);
watchdog_stop();
for(i = 0; i < nsectors; i++) {
COFFEE_ERASE(i);
PRINTF(".");
}
watchdog_start();
/* All file descriptors have become invalid. */
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
coffee_fd_set[i].flags = COFFEE_FD_FREE;
}
PRINTF("done!\n");
return 0;
}
/*---------------------------------------------------------------------------*/
void *
cfs_coffee_get_protected_mem(unsigned *size)
{
*size = sizeof(protected_mem);
return &protected_mem;
}