/*---------------------------------------------------------------------------*/
static struct file *
find_file(const char *name)
{
int i;
struct file_header hdr;
coffee_page_t page;
/* First check if the file metadata is cached. */
for(i = 0; i < COFFEE_MAX_OPEN_FILES; i++) {
if(FILE_FREE(&coffee_files[i])) {
continue;
}
read_header(&hdr, coffee_files[i].page);
if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr) && strcmp(name, hdr.name) == 0) {
return &coffee_files[i];
}
}
/* Scan the flash memory sequentially otherwise. */
for(page = 0; page < COFFEE_PAGE_COUNT; page = next_file(page, &hdr)) {
read_header(&hdr, page);
if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr) && strcmp(name, hdr.name) == 0) {
return load_file(page, &hdr);
}
}
return NULL;
}
/*---------------------------------------------------------------------------*/
int
cfs_readdir(struct cfs_dir *dir, struct cfs_dirent *record)
{
struct file_header hdr;
coffee_page_t page;
memcpy(&page, dir->dummy_space, sizeof(coffee_page_t));
while(page < COFFEE_PAGE_COUNT) {
read_header(&hdr, page);
if(HDR_ACTIVE(hdr) && !HDR_LOG(hdr)) {
coffee_page_t next_page;
memcpy(record->name, hdr.name, sizeof(record->name));
record->name[sizeof(record->name) - 1] = '\0';
record->size = file_end(page);
next_page = next_file(page, &hdr);
memcpy(dir->dummy_space, &next_page, sizeof(coffee_page_t));
return 0;
}
page = next_file(page, &hdr);
}
return -1;
}
/*---------------------------------------------------------------------------*/
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
}
/*---------------------------------------------------------------------------*/
static int
remove_by_page(coffee_page_t page, int remove_log, int close_fds,
int gc_allowed)
{
struct file_header hdr;
int i;
read_header(&hdr, page);
if(!HDR_ACTIVE(hdr)) {
return -1;
}
if(remove_log && HDR_MODIFIED(hdr)) {
if(remove_by_page(hdr.log_page, !REMOVE_LOG, !CLOSE_FDS, !ALLOW_GC) < 0) {
return -1;
}
}
hdr.flags |= HDR_FLAG_OBSOLETE;
write_header(&hdr, page);
*gc_wait = 0;
/* Close all file descriptors that reference the removed file. */
if(close_fds) {
for(i = 0; i < COFFEE_FD_SET_SIZE; i++) {
if(coffee_fd_set[i].file != NULL && coffee_fd_set[i].file->page == page) {
coffee_fd_set[i].flags = COFFEE_FD_FREE;
}
}
}
for(i = 0; i < COFFEE_MAX_OPEN_FILES; i++) {
if(coffee_files[i].page == page) {
coffee_files[i].page = INVALID_PAGE;
coffee_files[i].references = 0;
coffee_files[i].max_pages = 0;
}
}
#if !COFFEE_EXTENDED_WEAR_LEVELLING
if(gc_allowed) {
collect_garbage(GC_RELUCTANT);
}
#endif
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(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);
*(coffee_page_t *)dir->dummy_space = next_file(page, &hdr);
return 0;
}
page = next_file(page, &hdr);
}
return -1;
}
/*---------------------------------------------------------------------------*/
static coffee_page_t
get_sector_status(uint16_t sector, struct sector_status *stats)
{
static coffee_page_t skip_pages;
static char last_pages_are_active;
struct file_header hdr;
coffee_page_t active, obsolete, free;
coffee_page_t sector_start, sector_end;
coffee_page_t page;
memset(stats, 0, sizeof(*stats));
active = obsolete = free = 0;
/*
* get_sector_status() is an iterative function using local static
* state. It therefore requires that the caller starts iterating from
* sector 0 in order to reset the internal state.
*/
if(sector == 0) {
skip_pages = 0;
last_pages_are_active = 0;
}
sector_start = sector * COFFEE_PAGES_PER_SECTOR;
sector_end = sector_start + COFFEE_PAGES_PER_SECTOR;
/*
* Account for pages belonging to a file starting in a previous
* segment that extends into this segment. If the whole segment is
* covered, we do not need to continue counting pages in this iteration.
*/
if(last_pages_are_active) {
if(skip_pages >= COFFEE_PAGES_PER_SECTOR) {
stats->active = COFFEE_PAGES_PER_SECTOR;
skip_pages -= COFFEE_PAGES_PER_SECTOR;
return 0;
}
active = skip_pages;
} else {
if(skip_pages >= COFFEE_PAGES_PER_SECTOR) {
stats->obsolete = COFFEE_PAGES_PER_SECTOR;
skip_pages -= COFFEE_PAGES_PER_SECTOR;
return skip_pages >= COFFEE_PAGES_PER_SECTOR ? 0 : skip_pages;
}
obsolete = skip_pages;
}
/* Determine the amount of pages of each type that have not been
accounted for yet in the current sector. */
for(page = sector_start + skip_pages; page < sector_end;) {
read_header(&hdr, page);
last_pages_are_active = 0;
if(HDR_ACTIVE(hdr)) {
last_pages_are_active = 1;
page += hdr.max_pages;
active += hdr.max_pages;
} else if(HDR_ISOLATED(hdr)) {
page++;
obsolete++;
} else if(HDR_OBSOLETE(hdr)) {
page += hdr.max_pages;
obsolete += hdr.max_pages;
} else {
free = sector_end - page;
break;
}
}
/*
* Determine the amount of pages in the following sectors that
* should be remembered for the next iteration. This is necessary
* because no page except the first of a file contains information
* about what type of page it is. A side effect of remembering this
* amount is that there is no need to read in the headers of each
* of these pages from the storage.
*/
skip_pages = active + obsolete + free - 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;
}
}
stats->active = active;
stats->obsolete = obsolete;
stats->free = free;
/*
* To avoid unnecessary page isolation, we notify the caller that
* "skip_pages" pages should be isolated only if the current file extent
* ends in the next sector. If the file extent ends in a more distant
* sector, however, the garbage collection can free the next sector
* immediately without requiring page isolation.
*/
return (last_pages_are_active || (skip_pages >= COFFEE_PAGES_PER_SECTOR)) ?
0 : skip_pages;
}
/*---------------------------------------------------------------------------*/
static coffee_page_t
get_sector_status(uint16_t sector, struct sector_status *stats)
{
static coffee_page_t skip_pages;
static char last_pages_are_active;
struct file_header hdr;
coffee_page_t active, obsolete, free;
coffee_page_t sector_start, sector_end;
coffee_page_t page;
memset(stats, 0, sizeof(*stats));
active = obsolete = free = 0;
if(sector == 0) {
skip_pages = 0;
last_pages_are_active = 0;
}
sector_start = sector * COFFEE_PAGES_PER_SECTOR;
sector_end = sector_start + COFFEE_PAGES_PER_SECTOR;
if(last_pages_are_active) {
if(skip_pages >= COFFEE_PAGES_PER_SECTOR) {
stats->active = COFFEE_PAGES_PER_SECTOR;
skip_pages -= COFFEE_PAGES_PER_SECTOR;
return 0;
}
active = skip_pages;
} else {
if(skip_pages >= COFFEE_PAGES_PER_SECTOR) {
stats->obsolete = COFFEE_PAGES_PER_SECTOR;
skip_pages -= COFFEE_PAGES_PER_SECTOR;
return skip_pages >= COFFEE_PAGES_PER_SECTOR ? 0 : skip_pages;
}
obsolete = skip_pages;
}
for(page = sector_start + skip_pages; page < sector_end;) {
read_header(&hdr, page);
last_pages_are_active = 0;
if(HDR_ACTIVE(hdr)) {
last_pages_are_active = 1;
page += hdr.max_pages;
active += hdr.max_pages;
} else if(HDR_ISOLATED(hdr)) {
page++;
obsolete++;
} else if(HDR_OBSOLETE(hdr)) {
page += hdr.max_pages;
obsolete += hdr.max_pages;
} else {
free = sector_end - page;
break;
}
}
skip_pages = active + obsolete + free - 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;
}
}
stats->active = active;
stats->obsolete = obsolete;
stats->free = free;
return (last_pages_are_active || (skip_pages >= COFFEE_PAGES_PER_SECTOR)) ?
0 : skip_pages;
}
