/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_desc *fdp;
struct file *file;
#if COFFEE_MICRO_LOGS
struct file_header hdr;
struct log_param lp;
unsigned bytes_left;
int r;
#endif
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
}
/* If the file is allocated, read directly in the file. */
if(!FILE_MODIFIED(file)) {
COFFEE_READ(buf, size, absolute_offset(file->page, fdp->offset));
fdp->offset += size;
return size;
}
#if COFFEE_MICRO_LOGS
read_header(&hdr, file->page);
/*
* Fill the buffer by copying from the log in first hand, or the
* ordinary file if the page has no log record.
*/
for(bytes_left = size; bytes_left > 0; bytes_left -= r) {
r = -1;
lp.offset = fdp->offset;
lp.buf = buf;
lp.size = bytes_left;
r = read_log_page(&hdr, file->record_count, &lp);
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
COFFEE_READ(buf, lp.size, absolute_offset(file->page, fdp->offset));
r = lp.size;
}
fdp->offset += r;
buf = (char *)buf + r;
}
#endif /* COFFEE_MICRO_LOGS */
return size;
}
/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_desc *fdp;
struct file *file;
#if COFFEE_MICRO_LOGS
struct file_header hdr;
struct log_param lp;
unsigned bytes_left;
int r;
#endif
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
}
/* If the file is not modified, read directly from the file extent. */
if(!FILE_MODIFIED(file)) {
COFFEE_READ(buf, size, absolute_offset(file->page, fdp->offset));
fdp->offset += size;
return size;
}
#if COFFEE_MICRO_LOGS
read_header(&hdr, file->page);
/*
* Copy the contents of the most recent log record. If there is
* no log record for the file area to read from, we simply read
* from the original file extent.
*/
for(bytes_left = size; bytes_left > 0; bytes_left -= r) {
lp.offset = fdp->offset;
lp.buf = buf;
lp.size = bytes_left;
r = read_log_page(&hdr, file->record_count, &lp);
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
COFFEE_READ(buf, lp.size, absolute_offset(file->page, fdp->offset));
r = lp.size;
}
fdp->offset += r;
buf = (char *)buf + r;
}
#endif /* COFFEE_MICRO_LOGS */
return size;
}
static int
read_log_page(struct file_header *hdr, int16_t record_count,
struct log_param *lp)
{
uint16_t region;
int16_t match_index;
uint16_t log_record_size;
uint16_t log_records;
cfs_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 = record_count < 0 ? log_records : record_count;
match_index = get_record_index(hdr->log_page, search_records, region);
if(match_index < 0) {
return -1;
}
base = absolute_offset(hdr->log_page, log_records * sizeof(region));
base += (cfs_offset_t)match_index * log_record_size;
base += lp->offset;
COFFEE_READ(lp->buf, lp->size, base);
return lp->size;
}
/*---------------------------------------------------------------------------*/
static cfs_offset_t
file_end(coffee_page_t start)
{
struct file_header hdr;
unsigned char buf[COFFEE_PAGE_SIZE];
coffee_page_t page;
int i;
read_header(&hdr, start);
/*
* 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 = hdr.max_pages - 1; page >= 0; page--) {
COFFEE_READ(buf, sizeof(buf), (start + page) * COFFEE_PAGE_SIZE);
for(i = COFFEE_PAGE_SIZE - 1; i >= 0; i--) {
if(buf[i] != 0) {
if(page == 0 && i < sizeof(hdr)) {
return 0;
}
return 1 + i + (page * COFFEE_PAGE_SIZE) - sizeof(hdr);
}
}
}
/* All bytes are writable. */
return 0;
}
/*---------------------------------------------------------------------------*/
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
}
/*---------------------------------------------------------------------------*/
int
cfs_read(int fd, void *buf, unsigned size)
{
struct file_header hdr;
struct file_desc *fdp;
struct file *file;
unsigned bytes_left;
int r;
#if COFFEE_MICRO_LOGS
struct log_param lp;
#endif
if(!(FD_VALID(fd) && FD_READABLE(fd))) {
return -1;
}
fdp = &coffee_fd_set[fd];
file = fdp->file;
if(fdp->offset + size > file->end) {
size = file->end - fdp->offset;
}
bytes_left = size;
if(FILE_MODIFIED(file)) {
read_header(&hdr, file->page);
}
/*
* Fill the buffer by copying from the log in first hand, or the
* ordinary file if the page has no log record.
*/
while(bytes_left) {
watchdog_periodic();
r = -1;
#if COFFEE_MICRO_LOGS
if(FILE_MODIFIED(file)) {
lp.offset = fdp->offset;
lp.buf = buf;
lp.size = bytes_left;
r = read_log_page(&hdr, file->record_count, &lp);
}
#endif /* COFFEE_MICRO_LOGS */
/* Read from the original file if we cannot find the data in the log. */
if(r < 0) {
r = bytes_left;
COFFEE_READ(buf, r, absolute_offset(file->page, fdp->offset));
}
bytes_left -= r;
fdp->offset += r;
buf += r;
}
return size;
}
/*---------------------------------------------------------------------------*/
static int32_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;
uint32_t range_start, range_end, part_size;
READ_HEADER(&hdr, first_page);
for(search_limit = 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 > hdr.max_pages) {
range_end = hdr.max_pages;
}
/*
* 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 + range_start; 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
get_record_index(coffee_page_t log_page, uint16_t search_records,
uint16_t region)
{
cfs_offset_t base;
uint16_t processed;
uint16_t batch_size;
int16_t match_index, i;
base = absolute_offset(log_page, sizeof(uint16_t) * search_records);
batch_size = search_records > COFFEE_LOG_TABLE_LIMIT ?
COFFEE_LOG_TABLE_LIMIT : search_records;
processed = 0;
match_index = -1;
{
uint16_t indices[batch_size];
while(processed < search_records && match_index < 0) {
if(batch_size + processed > search_records) {
batch_size = search_records - processed;
}
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
find_next_record(struct file *file, coffee_page_t log_page,
int log_records)
{
int log_record, preferred_batch_size;
if(file->record_count >= 0) {
return file->record_count;
}
preferred_batch_size = log_records > COFFEE_LOG_TABLE_LIMIT ?
COFFEE_LOG_TABLE_LIMIT : log_records;
{
/* The next log record is unknown at this point; 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(log_record = 0; log_record < batch_size; log_record++) {
if(indices[log_record] == 0) {
log_record += processed;
break;
}
}
}
}
return log_record;
}
static int
write_log_page(struct file *file, 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;
cfs_offset_t offset;
struct log_param lp_out;
read_header(&hdr, 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(HDR_MODIFIED(hdr)) {
/* 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));
return merge_log(file->page, 0);
}
} else {
/* Create a log structure. */
log_page = create_log(file, &hdr);
if(log_page == INVALID_PAGE) {
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;
}
{
char copy_buf[log_record_size];
lp_out.offset = 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, log_record, &lp_out) < 0) {
COFFEE_READ(copy_buf, sizeof(copy_buf),
absolute_offset(file->page, offset));
}
memcpy(©_buf[lp->offset], lp->buf, lp->size);
/*
* Write the region number in the region index table.
* The region number is incremented to avoid values of zero.
*/
offset = absolute_offset(log_page, 0);
++region;
COFFEE_WRITE(®ion, sizeof(region),
offset + log_record * sizeof(region));
offset += log_records * sizeof(region);
COFFEE_WRITE(copy_buf, sizeof(copy_buf),
offset + log_record * log_record_size);
file->record_count = log_record + 1;
}
return lp->size;
}
/*---------------------------------------------------------------------------*/
static int
read_log_page(struct file_header *hdr, int16_t last_entry, struct log_param *lp)
{
uint16_t page;
int16_t match_index;
int16_t i;
uint16_t log_entry_size;
uint16_t log_entries;
unsigned long base;
uint16_t entry_count;
uint16_t search_entries;
log_entries = hdr->log_entries == 0 ?
COFFEE_LOG_SIZE / COFFEE_PAGE_SIZE : hdr->log_entries;
log_entry_size = hdr->log_entry_size == 0 ?
COFFEE_PAGE_SIZE : hdr->log_entry_size;
page = lp->offset / log_entry_size;
lp->offset %= log_entry_size;
if(lp->size > log_entry_size - lp->offset) {
lp->size = log_entry_size - lp->offset;
}
search_entries = last_entry < 0 ? log_entries : last_entry + 1;
entry_count = search_entries > COFFEE_LOG_TABLE_LIMIT ?
COFFEE_LOG_TABLE_LIMIT : search_entries;
{
uint16_t indices[entry_count];
uint16_t processed;
uint16_t current_batch_size;
base = ABS_OFFSET(hdr->log_page, sizeof(indices[0]) * search_entries);
processed = 0;
match_index = -1;
while(processed < search_entries && match_index < 0) {
if(entry_count + processed > search_entries) {
current_batch_size = search_entries - processed;
} else {
current_batch_size = entry_count;
}
base -= current_batch_size * sizeof(indices[0]);
COFFEE_READ(&indices, sizeof(indices[0]) * current_batch_size, base);
for(i = current_batch_size - 1; i >= 0; i--) {
if(indices[i] - 1 == page) {
match_index = search_entries - processed - (current_batch_size - i);
break;
}
}
processed += current_batch_size;
}
if(match_index == -1) {
return -1;
}
base = hdr->log_page * COFFEE_PAGE_SIZE;
base += sizeof(struct file_header) + log_entries * sizeof(page);
base += (unsigned long)match_index * log_entry_size;
base += lp->offset;
COFFEE_READ(lp->buf, lp->size, base);
}
return lp->size;
}
/*---------------------------------------------------------------------------*/
static void
get_sector_status(uint16_t sector, uint16_t *active,
uint16_t *free, uint16_t *obsolete) {
uint32_t offset, sector_start;
uint32_t end;
struct file_header hdr;
static int16_t skip_pages;
static int last_pages_are_active;
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;
while(offset < end) {
COFFEE_READ(&hdr, sizeof(hdr), offset);
if(COFFEE_PAGE_ACTIVE(hdr)) {
last_pages_are_active = 1;
offset += hdr.max_pages * COFFEE_PAGE_SIZE;
*active += hdr.max_pages;
} else if(COFFEE_PAGE_ISOLATED(hdr)) {
last_pages_are_active = 0;
offset += COFFEE_PAGE_SIZE;
*obsolete++;
} else if(COFFEE_PAGE_OBSOLETE(hdr)) {
last_pages_are_active = 0;
offset += hdr.max_pages * COFFEE_PAGE_SIZE;
*obsolete += hdr.max_pages;
} else if(COFFEE_PAGE_FREE(hdr)) {
*free = (end - offset) / COFFEE_PAGE_SIZE;
break;
}
}
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;
}
}
}
