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osd-contiki/core/cfs/cfs-coffee.c
nvt-se 15e8675ab9 Added file removal function to the CFS API. Only cfs-coffee and cfs-posix 
implements this, whereas the others just return -1.
2008-11-24 10:56:55 +00:00

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/*
* Copyright (c) 2008, Swedish Institute of Computer Science
* 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-contrained sensor systems.
* \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"
#include <limits.h>
#include <string.h>
#define DEBUG 0
#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 kb * 1024UL
#define Mb * (1024 kb)
#define COFFEE_FD_FREE 0x0
#define COFFEE_FD_READ 0x1
#define COFFEE_FD_WRITE 0x2
#define COFFEE_FD_APPEND 0x4
#define COFFEE_FD_MODIFIED 0x8
#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 FD_MODIFIED(fd) (coffee_fd_set[(fd)].flags & COFFEE_FD_MODIFIED)
/* File header flags. */
#define COFFEE_FLAG_VALID 0x1 /* Completely written header. */
#define COFFEE_FLAG_ALLOCATED 0x2 /* Allocated file. */
#define COFFEE_FLAG_OBSOLETE 0x4 /* File marked for GC. */
#define COFFEE_FLAG_MODIFIED 0x8 /* Modified file, log exists. */
#define COFFEE_FLAG_LOG 0x10 /* Log file. */
#define COFFEE_FLAG_ISOLATED 0x20 /* Isolated page. */
#define COFFEE_FILE_ALLOCATED(hdr) ((hdr).flags & COFFEE_FLAG_ALLOCATED)
#define COFFEE_FILE_FREE(hdr) !COFFEE_FILE_ALLOCATED(hdr)
#define COFFEE_FILE_LOG(hdr) ((hdr).flags & COFFEE_FLAG_LOG)
#define COFFEE_FILE_MODIFIED(hdr) ((hdr).flags & COFFEE_FLAG_MODIFIED)
#define COFFEE_FILE_ISOLATED(hdr) ((hdr).flags & COFFEE_FLAG_ISOLATED)
#define COFFEE_FILE_OBSOLETE(hdr) ((hdr).flags & COFFEE_FLAG_OBSOLETE)
#define COFFEE_FILE_ACTIVE(hdr) (COFFEE_FILE_ALLOCATED(hdr) && \
!COFFEE_FILE_OBSOLETE(hdr) && \
!COFFEE_FILE_ISOLATED(hdr))
#define COFFEE_PAGE_COUNT (COFFEE_SIZE / COFFEE_PAGE_SIZE)
#define COFFEE_PAGES_PER_SECTOR (COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE)
struct file_desc {
coffee_offset_t offset;
coffee_offset_t end;
coffee_page_t file_page;
coffee_page_t max_pages;
int16_t next_log_record;
uint8_t flags;
};
struct dir_cache {
coffee_offset_t page;
char filename_start;
};
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;
};
#define ABS_OFFSET(file_page, file_offset) \
((file_page) * COFFEE_PAGE_SIZE + \
sizeof(struct file_header) + (file_offset))
static struct dir_cache dir_cache[COFFEE_DIR_CACHE_ENTRIES];
static struct file_desc coffee_fd_set[COFFEE_FD_SET_SIZE];
/*---------------------------------------------------------------------------*/
static void
write_header(struct file_header *hdr, coffee_page_t page)
{
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);
}
/*---------------------------------------------------------------------------*/
static void
get_sector_status(uint16_t sector, coffee_page_t *active,
coffee_page_t *free, coffee_page_t *obsolete) {
static coffee_page_t skip_pages;
static int last_pages_are_active;
coffee_offset_t offset, sector_start;
coffee_offset_t end;
struct file_header hdr;
coffee_page_t jump;
int i;
*active = *free = *obsolete = 0;
if(sector == 0) {
skip_pages = 0;
last_pages_are_active = 0;
} else if(skip_pages > COFFEE_PAGES_PER_SECTOR) {
skip_pages -= COFFEE_PAGES_PER_SECTOR;
if(last_pages_are_active) {
*active = COFFEE_PAGES_PER_SECTOR;
} else {
*obsolete = COFFEE_PAGES_PER_SECTOR;
}
return;
}
sector_start = sector * COFFEE_SECTOR_SIZE;
if(last_pages_are_active) {
*active = skip_pages;
} 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 |= COFFEE_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);
}
offset = sector_start + skip_pages * COFFEE_PAGE_SIZE;
end = (sector + 1) * COFFEE_SECTOR_SIZE;
jump = 0;
while(offset < end) {
COFFEE_READ(&hdr, sizeof(hdr), offset);
last_pages_are_active = 0;
if(COFFEE_FILE_ACTIVE(hdr)) {
last_pages_are_active = 1;
jump = hdr.max_pages;
*active += jump;
} else if(COFFEE_FILE_ISOLATED(hdr)) {
jump = 1;
*obsolete++;
} else if(COFFEE_FILE_OBSOLETE(hdr)) {
jump = hdr.max_pages;
*obsolete += jump;
} else if(COFFEE_FILE_FREE(hdr)) {
*free = (end - offset) / COFFEE_PAGE_SIZE;
break;
}
offset += jump * COFFEE_PAGE_SIZE;
}
skip_pages = *active + *obsolete - COFFEE_PAGES_PER_SECTOR;
if(skip_pages > 0) {
if(last_pages_are_active) {
*active = COFFEE_PAGES_PER_SECTOR - *obsolete;
} else {
*obsolete = COFFEE_PAGES_PER_SECTOR - *active;
}
}
}
/*---------------------------------------------------------------------------*/
static void
dir_cache_add(char c, coffee_offset_t page)
{
int i;
for(i = 0; i < COFFEE_DIR_CACHE_ENTRIES; i++) {
if(dir_cache[i].filename_start == '\0') {
dir_cache[i].filename_start = c;
dir_cache[i].page = page;
break;
}
}
}
/*---------------------------------------------------------------------------*/
static void
dir_cache_del(coffee_offset_t page)
{
int i;
for(i = 0; i < COFFEE_DIR_CACHE_ENTRIES; i++) {
if(dir_cache[i].page == page) {
dir_cache[i].filename_start = '\0';
}
}
}
/*---------------------------------------------------------------------------*/
static coffee_offset_t
dir_cache_find(const char *name)
{
int i;
struct file_header hdr;
for(i = 0; i < COFFEE_DIR_CACHE_ENTRIES; i++) {
if(*name == dir_cache[i].filename_start) {
read_header(&hdr, dir_cache[i].page);
if(!COFFEE_FILE_ACTIVE(hdr)) {
dir_cache[i].filename_start = '\0';
} else if(strcmp(hdr.name, name) == 0) {
return dir_cache[i].page;
}
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
static coffee_offset_t
find_file(const char *name)
{
struct file_header hdr;
coffee_page_t page;
page = dir_cache_find(name);
if(page >= 0) {
return page;
}
page = 0;
do {
read_header(&hdr, page);
if(COFFEE_FILE_ACTIVE(hdr)) {
if(dir_cache_find(name) == -1) {
dir_cache_add(name[0], page);
}
if(strcmp(name, hdr.name) == 0) {
return page;
}
page += hdr.max_pages;
} else if(COFFEE_FILE_ISOLATED(hdr)) {
++page;
} else if(COFFEE_FILE_OBSOLETE(hdr)) {
page += hdr.max_pages;
} 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);
}
watchdog_periodic();
} while(page < COFFEE_PAGE_COUNT);
return -1;
}
/*---------------------------------------------------------------------------*/
static void
update_eof_hint(coffee_page_t file_page, coffee_offset_t end)
{
struct file_header hdr;
coffee_page_t current_page;
int part_size, i;
uint8_t eof_hint;
read_header(&hdr, file_page);
current_page = (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
find_offset_in_file(int first_page)
{
struct file_header hdr;
unsigned char buf[COFFEE_PAGE_SIZE];
int page;
int i;
int search_limit;
coffee_offset_t range_start, range_end, part_size;
read_header(&hdr, first_page);
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;
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
* a byte that has been modified.
*
* An important implication of this is that if the last written bytes
* are zeroes, then these are skipped from the calculation.
*/
for(page = first_page + range_end; page >= first_page; page--) {
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 == first_page) {
return i < sizeof(hdr) ? 0 : 1 + i - sizeof(hdr);
} else {
return 1 + i + (page - first_page) * COFFEE_PAGE_SIZE - sizeof(hdr);
}
}
}
}
/* All bytes are writable. */
return 0;
}
/*---------------------------------------------------------------------------*/
static int
find_contiguous_pages(unsigned wanted)
{
int page, start;
struct file_header hdr;
start = -1;
for(page = 0; page < COFFEE_PAGE_COUNT;) {
read_header(&hdr, page);
if(COFFEE_FILE_FREE(hdr)) {
if(start == -1) {
start = page;
} else {
if(start + wanted <= page) {
return start;
}
}
/* Jump to the next sector. */
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
} else if(COFFEE_FILE_ISOLATED(hdr)) {
++page;
} else {
start = -1;
page += hdr.max_pages;
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
static int
cfs_garbage_collect(void)
{
uint16_t sector;
coffee_page_t active_pages, free_pages, obsolete_pages;
int nerased;
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(nerased = sector = 0; sector < COFFEE_SIZE / COFFEE_SECTOR_SIZE; sector++) {
get_sector_status(sector, &active_pages, &free_pages, &obsolete_pages);
PRINTF("Coffee: Sector %u has %u active, %u free, and %u obsolete pages.\n",
sector, (unsigned)active_pages, (unsigned)free_pages, (unsigned)obsolete_pages);
if(active_pages == 0 && obsolete_pages > 0) {
COFFEE_ERASE(sector);
nerased++;
PRINTF("Coffee: Erased sector %d!\n", sector);
}
}
watchdog_start();
return nerased;
}
/*---------------------------------------------------------------------------*/
static int
remove_by_page(coffee_page_t page, int remove_log, int close_fds)
{
struct file_header hdr;
int i;
coffee_page_t log_page;
if(page >= COFFEE_PAGE_COUNT) {
return -1;
}
read_header(&hdr, page);
if(!COFFEE_FILE_ACTIVE(hdr)) {
return -1;
}
dir_cache_del(page);
hdr.flags |= COFFEE_FLAG_OBSOLETE;
write_header(&hdr, page);
if(remove_log && COFFEE_FILE_MODIFIED(hdr)) {
log_page = hdr.log_page;
dir_cache_del(log_page);
read_header(&hdr, log_page);
hdr.flags |= COFFEE_FLAG_OBSOLETE;
write_header(&hdr, log_page);
}
/* Close all file descriptors that reference the remove file. */
if(close_fds) {
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;
}
}
}
return 0;
}
/*---------------------------------------------------------------------------*/
static int
reserve(const char *name, uint32_t size, int allow_duplicates)
{
struct file_header hdr;
unsigned need_pages;
int page;
watchdog_stop();
if(!allow_duplicates && find_file(name) >= 0) {
watchdog_start();
return -1;
}
need_pages = (size + sizeof(hdr) + COFFEE_PAGE_SIZE - 1) / COFFEE_PAGE_SIZE;
page = find_contiguous_pages(need_pages);
if(page < 0) {
cfs_garbage_collect();
page = find_contiguous_pages(need_pages);
if(page < 0) {
watchdog_start();
return -1;
}
}
memcpy(hdr.name, name, sizeof(hdr.name));
hdr.name[sizeof(hdr.name) - 1] = '\0';
hdr.max_pages = need_pages;
hdr.flags = COFFEE_FLAG_ALLOCATED | COFFEE_FLAG_VALID;
hdr.log_page = 0;
hdr.eof_hint = 0;
hdr.log_records = 0;
hdr.log_record_size = 0;
write_header(&hdr, page);
PRINTF("Coffee: Reserved %u pages starting from %u for file %s\n",
need_pages, page, name);
dir_cache_add(name[0], page);
watchdog_start();
return page;
}
/*---------------------------------------------------------------------------*/
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)
{
coffee_offset_t base;
uint16_t processed;
uint16_t batch_size;
int16_t match_index, i;
uint16_t record_count;
base = ABS_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;
}
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;
}
}
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;
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;
}
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);
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);
}
memcpy(new, old, len);
memcpy(&new[len], suffix, sizeof(suffix));
return new;
}
/*---------------------------------------------------------------------------*/
static coffee_page_t
create_log(coffee_page_t file_page, struct file_header *hdr)
{
coffee_page_t log_page;
unsigned char log_name[sizeof(hdr->name)];
uint16_t log_record_size, log_records;
coffee_offset_t size;
int i;
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_page = reserve(create_log_name(log_name, sizeof(log_name), hdr->name),
size, 0);
if(log_page < 0) {
return -1;
}
hdr->flags |= COFFEE_FLAG_MODIFIED;
hdr->log_page = log_page;
write_header(hdr, file_page);
read_header(hdr, log_page);
hdr->flags |= COFFEE_FLAG_LOG;
write_header(hdr, log_page);
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
if(coffee_fd_set[i].file_page == file_page &&
coffee_fd_set[i].flags != COFFEE_FD_FREE) {
coffee_fd_set[i].flags |= COFFEE_FD_MODIFIED;
}
}
return log_page;
}
/*---------------------------------------------------------------------------*/
static int
merge_log(coffee_page_t file_page, int extend)
{
coffee_page_t log_page, new_file_page;
struct file_header hdr, hdr2;
int fd, n;
coffee_offset_t offset;
coffee_page_t max_pages;
read_header(&hdr, file_page);
log_page = hdr.log_page;
fd = cfs_open(hdr.name, CFS_READ);
if(fd < 0) {
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 * (1 << extend);
new_file_page = reserve(hdr.name,
max_pages * COFFEE_PAGE_SIZE - sizeof(hdr),
1);
if(new_file_page < 0) {
cfs_close(fd);
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);
cfs_close(fd);
return -1;
} else if(n > 0) {
COFFEE_WRITE(buf, n,
ABS_OFFSET(new_file_page, offset));
offset += n;
}
} while(n != 0);
if(remove_by_page(file_page, 1, 0) < 0) {
remove_by_page(new_file_page, 0, 0);
cfs_close(fd);
return -1;
}
/* 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 = hdr.eof_hint;
write_header(&hdr2, new_file_page);
/* Point the file descriptors to the new file page. */
for(n = 0; n < COFFEE_FD_SET_SIZE; n++) {
if(coffee_fd_set[n].file_page == file_page) {
coffee_fd_set[n].file_page = new_file_page;
coffee_fd_set[n].max_pages = max_pages;
coffee_fd_set[n].flags &= ~COFFEE_FD_MODIFIED;
coffee_fd_set[n].next_log_record = -1;
}
}
cfs_close(fd);
return 0;
}
/*---------------------------------------------------------------------------*/
static int
find_next_record(struct file_desc *fdp, 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(fdp->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]),
ABS_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 = fdp->next_log_record;
}
return log_record;
}
/*---------------------------------------------------------------------------*/
static int
write_log_page(struct file_desc *fdp, struct log_param *lp)
{
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;
struct log_param lp_out;
read_header(&hdr, fdp->file_page);
adjust_log_config(&hdr, &log_record_size, &log_records);
region = modify_log_buffer(log_record_size, &lp->offset, &lp->size);
log_page = 0;
if(COFFEE_FILE_MODIFIED(hdr)) {
/* A log structure has already been created. */
log_page = hdr.log_page;
log_record = find_next_record(fdp, 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);
update_eof_hint(fdp->file_page, fdp->end);
return merge_log(fdp->file_page, 0);
}
} else {
/* Create a log structure. */
log_page = create_log(fdp->file_page, &hdr);
if(log_page < 0) {
return -1;
}
PRINTF("Coffee: Created a log structure for file %s at page %u\n",
hdr.name, (unsigned)log_page);
hdr.log_page = log_page;
log_record = 0;
}
{
unsigned char copy_buf[log_record_size];
lp_out.offset = region * log_record_size;
lp_out.buf = copy_buf;
lp_out.size = log_record_size;
if((lp->offset > 0 || lp->size != log_record_size) &&
read_log_page(&hdr, fdp->next_log_record - 1, &lp_out) < 0) {
COFFEE_READ(copy_buf, sizeof(copy_buf),
ABS_OFFSET(fdp->file_page, region * log_record_size));
}
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;
COFFEE_WRITE(copy_buf, sizeof(copy_buf), base);
++region;
COFFEE_WRITE(&region, sizeof(region),
ABS_OFFSET(log_page, log_record * sizeof(region)));
fdp->next_log_record = log_record + 1;
}
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) {
return i;
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
int
cfs_open(const char *name, int flags)
{
int fd;
int page;
struct file_header hdr;
struct file_desc *fdp;
fd = get_available_fd();
if(fd < 0) {
PRINTF("Coffee: Failed to allocate a new file descriptor!\n");
return -1;
}
fdp = &coffee_fd_set[fd];
page = find_file(name);
if(page < 0) {
if((flags & (CFS_READ | CFS_WRITE)) == CFS_READ) {
return -1;
}
if((page = reserve(name, COFFEE_DYN_SIZE, 1)) < 0) {
return -1;
}
fdp->max_pages = (COFFEE_DYN_SIZE + sizeof(hdr) +
COFFEE_PAGE_SIZE - 1) / COFFEE_PAGE_SIZE;
} else {
read_header(&hdr, page);
if(COFFEE_FILE_MODIFIED(hdr)) {
fdp->flags = COFFEE_FD_MODIFIED;
} else
fdp->max_pages = hdr.max_pages;
}
fdp->file_page = page;
fdp->flags |= flags;
fdp->end = find_offset_in_file(page);
fdp->offset = flags & CFS_APPEND ? fdp->end : 0;
fdp->next_log_record = 0;
return fd;
}
/*---------------------------------------------------------------------------*/
void
cfs_close(int fd)
{
if(FD_VALID(fd)) {
update_eof_hint(coffee_fd_set[fd].file_page, coffee_fd_set[fd].end);
coffee_fd_set[fd].flags = COFFEE_FD_FREE;
}
}
/*---------------------------------------------------------------------------*/
unsigned
cfs_seek(int fd, unsigned offset)
{
struct file_header hdr;
if(!FD_VALID(fd)) {
return -1;
}
read_header(&hdr, coffee_fd_set[fd].file_page);
/* Check if the offset is within the file boundary. */
if(sizeof(hdr) + offset >= hdr.max_pages * COFFEE_PAGE_SIZE ||
sizeof(hdr) + offset < offset) {
return -1;
}
if(coffee_fd_set[fd].end < offset) {
coffee_fd_set[fd].end = offset;
}
return coffee_fd_set[fd].offset = offset;
}
/*---------------------------------------------------------------------------*/
int
cfs_remove(const char *name)
{
int page;
/*
* 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.
*/
page = find_file(name);
if(page < 0) {
return -1;
}
return remove_by_page(page, 1, 1);
}
/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_header hdr;
struct file_desc *fdp;
unsigned remains, read_chunk;
int r;
coffee_offset_t base, offset;
struct log_param lp;
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
if(fdp->offset + size > fdp->end) {
size = fdp->end - fdp->offset;
}
read_chunk = COFFEE_PAGE_SIZE;
if(FD_MODIFIED(fd)) {
read_header(&hdr, fdp->file_page);
if(hdr.log_record_size > 0) {
read_chunk = hdr.log_record_size;
}
}
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.
*/
while(remains) {
watchdog_periodic();
r = -1;
if(FD_MODIFIED(fd)) {
lp.offset = base + offset;
lp.buf = (char *)buf + offset;
lp.size = remains;
r = read_log_page(&hdr, fdp->next_log_record - 1, &lp);
}
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
r = remains > read_chunk ? read_chunk : remains;
COFFEE_READ((char *) buf + offset, r,
ABS_OFFSET(fdp->file_page, base + offset));
}
remains -= r;
offset += r;
}
fdp->offset += offset;
return offset;
}
/*---------------------------------------------------------------------------*/
int
cfs_write(int fd, const void *buf, unsigned size)
{
struct file_desc *fdp;
int i;
struct log_param lp;
coffee_offset_t remains;
if(!(FD_VALID(fd) && FD_WRITABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
/* Attempt to extend the file if we try to write past the end. */
while(size + fdp->offset + sizeof(struct file_header) >
fdp->max_pages * COFFEE_PAGE_SIZE) {
update_eof_hint(fdp->file_page, fdp->end);
if(merge_log(fdp->file_page, 1) < 0) {
return -1;
}
}
if(fdp->offset < fdp->end) {
remains = size;
while(remains) {
lp.offset = fdp->offset;
lp.buf = (char *)buf + size - remains;
lp.size = remains;
i = write_log_page(fdp, &lp);
if(i == 0) {
/* The file was merged with the log. Try again. */
continue;
}
if(i < 0) {
return size - remains > 0 ? size - remains : -1;
}
remains -= i;
fdp->offset += i;
}
} else {
COFFEE_WRITE(buf, size,
ABS_OFFSET(fdp->file_page, fdp->offset));
fdp->offset += size;
}
if(fdp->offset > fdp->end) {
/*
* The file has been extended and the file descriptors
* referencing this file must be updated.
*/
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
if(coffee_fd_set[i].file_page == fdp->file_page) {
coffee_fd_set[i].end = coffee_fd_set[i].offset;
}
}
}
return size;
}
/*---------------------------------------------------------------------------*/
int
cfs_opendir(struct cfs_dir *dir, const char *name)
{
/* We have only a root directory. */
if(name[0] != '/' || name[1] != '\0') {
return -1;
}
*(coffee_page_t *)dir->dummy_space = 0;
return 0;
}
/*---------------------------------------------------------------------------*/
int
cfs_readdir(struct cfs_dir *dir, struct cfs_dirent *record)
{
struct file_header hdr;
coffee_page_t page;
for(page = *(coffee_page_t *)dir->dummy_space; page < COFFEE_PAGE_COUNT;) {
watchdog_periodic();
read_header(&hdr, page);
if(COFFEE_FILE_FREE(hdr)) {
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
} else if(COFFEE_FILE_ISOLATED(hdr)) {
++page;
} else if(COFFEE_FILE_ACTIVE(hdr) && !COFFEE_FILE_LOG(hdr)) {
memcpy(record->name, hdr.name, sizeof(record->name));
record->name[sizeof(record->name) - 1] = '\0';
record->size = find_offset_in_file(page);
page += hdr.max_pages;
*(coffee_page_t *)dir->dummy_space = page;
return 0;
} else {
page += hdr.max_pages;
}
}
return -1;
}
/*---------------------------------------------------------------------------*/
void
cfs_closedir(struct cfs_dir *dir)
{
return;
}
/*---------------------------------------------------------------------------*/
int
cfs_coffee_reserve(const char *name, uint32_t size)
{
return reserve(name, size, 0);
}
/*---------------------------------------------------------------------------*/
int
cfs_coffee_configure_log(const char *file, unsigned log_size,
unsigned log_record_size)
{
coffee_page_t page;
struct file_header hdr;
if(log_record_size == 0 || log_record_size > COFFEE_PAGE_SIZE ||
log_size < log_record_size) {
return -1;
}
page = find_file(file);
if(page < 0) {
return -1;
}
read_header(&hdr, page);
if(COFFEE_FILE_MODIFIED(hdr)) {
/* Too late to customize the log. */
return -1;
}
hdr.log_records = log_size / log_record_size;
hdr.log_record_size = log_record_size;
write_header(&hdr, page);
return 0;
}
/*---------------------------------------------------------------------------*/
int
cfs_coffee_format(void)
{
int nsectors, i;
nsectors = COFFEE_SIZE / COFFEE_SECTOR_SIZE;
/* 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;
}
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