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 coffee_page_t
create_log(struct file *file, struct file_header *hdr)
{
coffee_page_t log_page;
uint16_t log_record_size, log_records;
cfs_offset_t size;
struct file *log_file;
adjust_log_config(hdr, &log_record_size, &log_records);
/* Log index size + log data size. */
size = log_records * (sizeof(uint16_t) + log_record_size);
log_file = reserve(hdr->name, page_count(size), 1, HDR_FLAG_LOG);
if(log_file == NULL) {
return INVALID_PAGE;
}
log_page = log_file->page;
hdr->flags |= HDR_FLAG_MODIFIED;
hdr->log_page = log_page;
write_header(hdr, file->page);
file->flags |= COFFEE_FILE_MODIFIED;
return log_page;
}
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;
}
