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Checking boot sector for dirty bit.

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Some OSos use reseved byte of boot sector to set state of the file
system. If first bit set, then filesystem is proably damaged - write
operation was not finished/cache not snycted/...

Signed-off-by: Oleksij Rempel <bug-track@fisher-privat.net>
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
This commit is contained in:
Oleksij Rempel 2013-01-23 12:35:13 +01:00 committed by Daniel Baumann
parent f33ee8ca56
commit ce2f8dc349
2 changed files with 43 additions and 0 deletions
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41
src/boot.c
View File

@ -291,6 +291,45 @@ static void read_fsinfo(DOS_FS * fs, struct boot_sector *b, int lss)
fs->free_clusters = CF_LE_L(i.free_clusters);
}
static char print_fat_dirty_state(void)
{
printf("Dirty bit is set. Fs was not properly unmounted and"
" some data may be corrupt.\n");
if (interactive) {
printf("1) Remove dirty bit\n"
"2) No action\n");
return get_key("12", "?");
} else
printf(" Automaticaly removing dirty bit.\n");
return '1';
}
static void check_fat_state_bit (DOS_FS *fs, void *b)
{
if (fs->fat_bits == 32) {
struct boot_sector *b32 = b;
if (b32->reserved3 & FAT_STATE_DIRTY) {
printf("0x41: ");
if (print_fat_dirty_state() == '1') {
b32->reserved3 &= ~FAT_STATE_DIRTY;
fs_write(0, sizeof(*b32), b32);
}
}
} else {
struct boot_sector_16 *b16 = b;
if (b16->reserved2 & FAT_STATE_DIRTY) {
printf("0x25: ");
if (print_fat_dirty_state() == '1') {
b16->reserved2 &= ~FAT_STATE_DIRTY;
fs_write(0, sizeof(*b16), b16);
}
}
}
}
void read_boot(DOS_FS * fs)
{
struct boot_sector b;
@ -363,6 +402,7 @@ void read_boot(DOS_FS * fs)
" This may lead to problems on some systems.\n",
fs->clusters, FAT16_THRESHOLD);
check_fat_state_bit(fs, &b);
fs->backupboot_start = CF_LE_W(b.backup_boot) * logical_sector_size;
check_backup_boot(fs, &b, logical_sector_size);
@ -373,6 +413,7 @@ void read_boot(DOS_FS * fs)
fs->fat_bits = (fs->clusters >= FAT12_THRESHOLD) ? 16 : 12;
if (fs->clusters >= FAT16_THRESHOLD)
die("Too many clusters (%lu) for FAT16 filesystem.", fs->clusters);
check_fat_state_bit(fs, &b);
} else {
/* On Atari, things are more difficult: GEMDOS always uses 12bit FATs
* on floppies, and always 16 bit on harddisks. */

2
src/dosfsck.h
View File

@ -57,6 +57,8 @@
#define VFAT_LN_ATTR (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
#define FAT_STATE_DIRTY 0x01
/* ++roman: Use own definition of boot sector structure -- the kernel headers'
* name for it is msdos_boot_sector in 2.0 and fat_boot_sector in 2.1 ... */
struct boot_sector {