/*
* This function forces out the primary superblock. We need to only
* write out those fields which we have changed, since if the
* filesystem is mounted, it may have changed some of the other
* fields.
*
* It takes as input a superblock which has already been byte swapped
* (if necessary).
*
*/
static errcode_t write_primary_superblock(ext2_filsys fs,
struct ext2_super_block *super)
{
__u16 *old_super, *new_super;
int check_idx, write_idx, size;
errcode_t retval;
if (!fs->io->manager->write_byte || !fs->orig_super) {
io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE,
super);
io_channel_set_blksize(fs->io, fs->blocksize);
return retval;
}
old_super = (__u16 *) fs->orig_super;
new_super = (__u16 *) super;
for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
if (old_super[check_idx] == new_super[check_idx])
continue;
write_idx = check_idx;
for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
if (old_super[check_idx] == new_super[check_idx])
break;
size = 2 * (check_idx - write_idx);
retval = io_channel_write_byte(fs->io,
SUPERBLOCK_OFFSET + (2 * write_idx), size,
new_super + write_idx);
if (retval)
return retval;
}
memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
return 0;
}
static errcode_t test_write_byte(io_channel channel, unsigned long offset,
int count, const void *buf)
{
struct test_private_data *data;
errcode_t retval = 0;
EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
data = (struct test_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_TEST_IO_CHANNEL);
if (data->real && data->real->manager->write_byte)
retval = io_channel_write_byte(data->real, offset, count, buf);
if (data->write_byte)
data->write_byte(offset, count, retval);
else
printf("Test_io: write_byte(%lu, %d) returned %s\n",
offset, count, retval ? error_message(retval) : "OK");
return retval;
}
/*
* This function forces out the primary superblock. We need to only
* write out those fields which we have changed, since if the
* filesystem is mounted, it may have changed some of the other
* fields.
*
* It takes as input a superblock which has already been byte swapped
* (if necessary).
*
*/
static errcode_t write_primary_superblock(ext2_filsys fs,
struct ext2_super_block *super)
{
__u16 *old_super, *new_super;
int check_idx, write_idx, size;
errcode_t retval;
if (!fs->io->manager->write_byte || !fs->orig_super) {
fallback:
io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
super);
io_channel_set_blksize(fs->io, fs->blocksize);
return retval;
}
old_super = (__u16 *) fs->orig_super;
new_super = (__u16 *) super;
for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
if (old_super[check_idx] == new_super[check_idx])
continue;
write_idx = check_idx;
for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
if (old_super[check_idx] == new_super[check_idx])
break;
size = 2 * (check_idx - write_idx);
#if 0
printf("Writing %d bytes starting at %d\n",
size, write_idx*2);
#endif
retval = io_channel_write_byte(fs->io,
SUPERBLOCK_OFFSET + (2 * write_idx), size,
new_super + write_idx);
if (retval == EXT2_ET_UNIMPLEMENTED)
goto fallback;
if (retval)
return retval;
}
memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
return 0;
}
