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Faster search for backup ext2/ext3/ext4 superblock

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This commit is contained in:
Christophe Grenier 2009-08-18 08:51:11 +02:00
parent 727db32485
commit 903945f4c9
1 changed files with 54 additions and 39 deletions
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53
src/ext2_sbn.c
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@ -37,6 +37,38 @@
#include "ext2.h"
#include "ext2_sbn.h"
static const uint64_t group_size[3]={
((EXT2_MIN_BLOCK_SIZE<<0)*8*(EXT2_MIN_BLOCK_SIZE<<0)+2*512),
(EXT2_MIN_BLOCK_SIZE<<1)*8*(EXT2_MIN_BLOCK_SIZE<<1),
(EXT2_MIN_BLOCK_SIZE<<2)*8*(EXT2_MIN_BLOCK_SIZE<<2),
};
static const uint64_t factors[3]={3,5,7};
static uint64_t next_sb(const uint64_t hd_offset_old)
{
uint64_t hd_offset=0;
int j;
if(hd_offset_old < EXT2_MIN_BLOCK_SIZE<<0)
hd_offset=EXT2_MIN_BLOCK_SIZE<<0;
else if(hd_offset_old < EXT2_MIN_BLOCK_SIZE<<1)
hd_offset=EXT2_MIN_BLOCK_SIZE<<1;
else if(hd_offset_old < EXT2_MIN_BLOCK_SIZE<<2)
hd_offset=EXT2_MIN_BLOCK_SIZE<<2;
for(j=0; j<3; j++)
{
int i;
for(i=0; i<3; i++)
{
uint64_t val;
for(val=1; val * group_size[j] <= hd_offset_old; val*=factors[i])
;
if(hd_offset==0 || val * group_size[j] < hd_offset)
hd_offset=val* group_size[j];
}
}
return hd_offset;
}
list_part_t *search_superblock(disk_t *disk_car, const partition_t *partition, const int verbose, const int dump_ind, const int interface)
{
unsigned char *buffer=(unsigned char *)MALLOC(2*0x200);
@ -65,7 +97,7 @@ list_part_t *search_superblock(disk_t *disk_car, const partition_t *partition, c
wattroff(stdscr, A_REVERSE);
}
#endif
for(hd_offset=0;hd_offset<partition->part_size && nbr_sb<10 && ind_stop==0;hd_offset+=DEFAULT_SECTOR_SIZE)
for(hd_offset=0;hd_offset<partition->part_size && nbr_sb<10 && ind_stop==0;hd_offset=next_sb(hd_offset))
{
#ifdef HAVE_NCURSES
unsigned long int percent;
@ -81,25 +113,9 @@ list_part_t *search_superblock(disk_t *disk_car, const partition_t *partition, c
old_percent=percent;
}
#endif
/* ext2/ext3/ext4 */
if( hd_offset==(EXT2_MIN_BLOCK_SIZE<<0) ||
hd_offset==(EXT2_MIN_BLOCK_SIZE<<1) ||
hd_offset==(EXT2_MIN_BLOCK_SIZE<<2) ||
hd_offset==(1*(EXT2_MIN_BLOCK_SIZE<<0)*8*(EXT2_MIN_BLOCK_SIZE<<0)+2*512) ||
hd_offset==(1*(EXT2_MIN_BLOCK_SIZE<<1)*8*(EXT2_MIN_BLOCK_SIZE<<1)) ||
hd_offset==(1*(EXT2_MIN_BLOCK_SIZE<<2)*8*(EXT2_MIN_BLOCK_SIZE<<2)) ||
hd_offset%(3*(EXT2_MIN_BLOCK_SIZE<<0)*8*(EXT2_MIN_BLOCK_SIZE<<0)+2*512)==0 ||
hd_offset%(5*(EXT2_MIN_BLOCK_SIZE<<0)*8*(EXT2_MIN_BLOCK_SIZE<<0)+2*512)==0 ||
hd_offset%(7*(EXT2_MIN_BLOCK_SIZE<<0)*8*(EXT2_MIN_BLOCK_SIZE<<0)+2*512)==0 ||
hd_offset%(3*(EXT2_MIN_BLOCK_SIZE<<1)*8*(EXT2_MIN_BLOCK_SIZE<<1))==0 ||
hd_offset%(5*(EXT2_MIN_BLOCK_SIZE<<1)*8*(EXT2_MIN_BLOCK_SIZE<<1))==0 ||
hd_offset%(7*(EXT2_MIN_BLOCK_SIZE<<1)*8*(EXT2_MIN_BLOCK_SIZE<<1))==0 ||
hd_offset%(3*(EXT2_MIN_BLOCK_SIZE<<2)*8*(EXT2_MIN_BLOCK_SIZE<<2))==0 ||
hd_offset%(5*(EXT2_MIN_BLOCK_SIZE<<2)*8*(EXT2_MIN_BLOCK_SIZE<<2))==0 ||
hd_offset%(7*(EXT2_MIN_BLOCK_SIZE<<2)*8*(EXT2_MIN_BLOCK_SIZE<<2))==0)
{
if(disk_car->pread(disk_car, buffer, 1024, partition->part_offset + hd_offset) == 1024)
{
/* ext2/ext3/ext4 */
if(le16(sb->s_magic)==EXT2_SUPER_MAGIC)
{
dup_partition_t(new_partition,partition);
@ -127,7 +143,6 @@ list_part_t *search_superblock(disk_t *disk_car, const partition_t *partition, c
}
}
}
}
free(new_partition);
free(buffer);
return list_part;