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activated EOF hints and fixed a bug in the garbage collector.

This commit is contained in:
nvt-se 2008-08-25 09:57:38 +00:00
parent d28b27f031
commit e483f335ce
1 changed files with 140 additions and 82 deletions
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132
core/cfs/cfs-coffee.c
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@ -43,6 +43,7 @@
#include "cfs/cfs-coffee.h"
#include "dev/watchdog.h"
#include <limits.h>
#include <string.h>
#define DEBUG 0
@ -66,34 +67,36 @@
#define COFFEE_FD_APPEND 0x4
#define COFFEE_FD_FREE 0x0
#define COFFEE_PAGE_COUNT (COFFEE_SIZE / COFFEE_PAGE_SIZE)
#define COFFEE_PAGES_PER_SECTOR (COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE)
#define COFFEE_FLAG_VALID 0x1
#define COFFEE_FLAG_ALLOCATED 0x2
#define COFFEE_FLAG_OBSOLETE 0x4
#define COFFEE_FLAG_MODIFIED 0x8
#define COFFEE_FLAG_LOG 0x10
#define LOG_CMD_MAGIC 0x7a
#define COFFEE_PAGE_ALLOCATED(hdr) ((hdr).flags & COFFEE_FLAG_ALLOCATED)
#define COFFEE_PAGE_FREE(hdr) !COFFEE_PAGE_ALLOCATED(hdr)
#define COFFEE_PAGE_OBSOLETE(hdr) ((hdr).flags & COFFEE_FLAG_OBSOLETE)
#define COFFEE_PAGE_ACTIVE(hdr) \
(COFFEE_PAGE_ALLOCATED(hdr) && !COFFEE_PAGE_OBSOLETE(hdr))
#define COFFEE_PAGE_LOG(hdr) ((hdr).flags & COFFEE_FLAG_LOG)
#define COFFEE_PAGE_MODIFIED(hdr) ((hdr).flags & COFFEE_FLAG_MODIFIED)
#define FD_VALID(fd) \
((fd) < COFFEE_FD_SET_SIZE && coffee_fd_set[(fd)].flags != COFFEE_FD_FREE)
((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)
/* 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_PAGE_ALLOCATED(hdr) ((hdr).flags & COFFEE_FLAG_ALLOCATED)
#define COFFEE_PAGE_FREE(hdr) !COFFEE_PAGE_ALLOCATED(hdr)
#define COFFEE_PAGE_LOG(hdr) ((hdr).flags & COFFEE_FLAG_LOG)
#define COFFEE_PAGE_MODIFIED(hdr) ((hdr).flags & COFFEE_FLAG_MODIFIED)
#define COFFEE_PAGE_ISOLATED(hdr) ((hdr).flags & COFFEE_FLAG_ISOLATED)
#define COFFEE_PAGE_OBSOLETE(hdr) ((hdr).flags & COFFEE_FLAG_OBSOLETE)
#define COFFEE_PAGE_ACTIVE(hdr) (COFFEE_PAGE_ALLOCATED(hdr) && \
!COFFEE_PAGE_OBSOLETE(hdr) && \
!COFFEE_PAGE_ISOLATED(hdr))
#define COFFEE_PAGE_COUNT (COFFEE_SIZE / COFFEE_PAGE_SIZE)
#define COFFEE_PAGES_PER_SECTOR (COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE)
#define READ_HEADER(hdr, page) \
COFFEE_READ((hdr), sizeof(*hdr), (page) * COFFEE_PAGE_SIZE)
#define WRITE_HEADER(hdr, page) \
COFFEE_WRITE((hdr), sizeof(*hdr), (page) * COFFEE_PAGE_SIZE)
@ -139,11 +142,12 @@ static struct file_desc coffee_fd_set[COFFEE_FD_SET_SIZE];
static void
get_sector_status(uint16_t sector, uint16_t *active,
uint16_t *free, uint16_t *obsolete) {
uint32_t offset;
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) {
@ -159,12 +163,27 @@ get_sector_status(uint16_t sector, uint16_t *active,
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;
}
offset = sector * COFFEE_SECTOR_SIZE + skip_pages * 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) {
@ -177,6 +196,10 @@ get_sector_status(uint16_t sector, uint16_t *active,
last_pages_are_active = 0;
offset += hdr.max_pages * COFFEE_PAGE_SIZE;
*obsolete += hdr.max_pages;
} else if(COFFEE_PAGE_ISOLATED(hdr)) {
last_pages_are_active = 0;
offset += COFFEE_PAGE_SIZE;
*obsolete++;
} else if(COFFEE_PAGE_FREE(hdr)) {
*free = (end - offset) / COFFEE_PAGE_SIZE;
break;
@ -262,6 +285,8 @@ find_file(const char *name)
page += hdr.max_pages;
} else if(COFFEE_PAGE_OBSOLETE(hdr)) {
page += hdr.max_pages;
} else if(COFFEE_PAGE_ISOLATED(hdr)) {
++page;
} else {
/* It follows from the properties of the page allocation algorithm
that if a free page is encountered, then the rest of the sector
@ -281,18 +306,31 @@ find_offset_in_file(int first_page)
unsigned char buf[COFFEE_PAGE_SIZE];
int page;
int i;
int search_limit, 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);
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 file towards the beginning and look for
* 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 + hdr.max_pages - 1; page >= first_page; page--) {
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--) {
@ -329,6 +367,8 @@ find_contiguous_pages(unsigned wanted)
}
/* Jump to the next sector. */
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
} else if(COFFEE_PAGE_ISOLATED(hdr)) {
++page;
} else {
start = -1;
page += hdr.max_pages;
@ -361,21 +401,17 @@ cfs_garbage_collect(void)
COFFEE_ERASE(sector);
PRINTF("Coffee: Erased sector %d!\n", sector);
++sectors_in_row;
} else {
if(sectors_in_row > longest_row) {
longest_row = sectors_in_row;
}
} else {
sectors_in_row = 0;
}
}
if(sectors_in_row > longest_row) {
longest_row = sectors_in_row;
}
watchdog_start();
return longest_row * (COFFEE_PAGES_PER_SECTOR);
return longest_row * COFFEE_PAGES_PER_SECTOR;
}
/*---------------------------------------------------------------------------*/
static int
@ -653,7 +689,7 @@ write_log_page(struct file_desc *fdp, struct log_param *lp)
if(log_entry >= log_entries) {
/* The log is full. The new file should be written out. */
PRINTF("Coffee: The log for file %s is full\n", hdr.name);
PRINTF("Coffee: Flushing the log for file %s\n", hdr.name);
fdp->next_log_entry = 0;
return flush_log(fdp->file_page);
}
@ -732,7 +768,8 @@ cfs_open(const char *name, int flags)
if((page = cfs_coffee_reserve(name, COFFEE_DYN_SIZE)) < 0) {
return -1;
}
coffee_fd_set[fd].max_pages = COFFEE_DYN_SIZE / COFFEE_PAGE_SIZE;
coffee_fd_set[fd].max_pages = (COFFEE_DYN_SIZE + sizeof(hdr) +
COFFEE_PAGE_SIZE - 1) / COFFEE_PAGE_SIZE;
} else {
READ_HEADER(&hdr, page);
coffee_fd_set[fd].max_pages = hdr.max_pages;
@ -750,7 +787,25 @@ cfs_open(const char *name, int flags)
void
cfs_close(int fd)
{
struct file_header hdr;
uint16_t current_page, i;
int part_size;
uint8_t eof_hint;
if(FD_VALID(fd)) {
READ_HEADER(&hdr, coffee_fd_set[fd].file_page);
current_page = (coffee_fd_set[fd].end + COFFEE_PAGE_SIZE - 1) / COFFEE_PAGE_SIZE;
part_size = hdr.max_pages / (sizeof(hdr.eof_hint) * CHAR_BIT);
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, coffee_fd_set[fd].file_page);
}
coffee_fd_set[fd].flags = COFFEE_FD_FREE;
}
}
@ -918,16 +973,19 @@ cfs_readdir(struct cfs_dir *dir, struct cfs_dirent *entry)
for(page = *(uint16_t *)dir->dummy_space; page < COFFEE_PAGE_COUNT;) {
watchdog_periodic();
READ_HEADER(&hdr, page);
if(COFFEE_PAGE_FREE(hdr)) {
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
} else if(COFFEE_PAGE_ISOLATED(hdr)) {
++page;
} else {
if(COFFEE_PAGE_ACTIVE(hdr) && !COFFEE_PAGE_LOG(hdr)) {
memcpy(entry->name, hdr.name, sizeof(entry->name));
entry->name[sizeof(entry->name) - 1] = '\0';
entry->size = find_offset_in_file(page);
page += hdr.max_pages;
*(uint16_t *)dir->dummy_space = page;
page += hdr.max_pages;
return 0;
} else if (COFFEE_PAGE_FREE(hdr)) {
page = (page + COFFEE_PAGES_PER_SECTOR) & ~(COFFEE_PAGES_PER_SECTOR - 1);
} else {
}
page += hdr.max_pages;
}
}