void FileSystemUnix::resolveIndirectDataBlocks(Inode* inode, sector_addr_t indirect_block, uint16 degree_of_indirection, uint16 sector_addr_len)
{
if(indirect_block == UNUSED_DATA_BLOCK)
{
debug(FS_UNIX, "resolveIndirectDataBlocks - indirect_block is not in use - quit\n");
return;
}
if(degree_of_indirection == 0)
{
debug(FS_UNIX, "resolveIndirectDataBlocks - sorry this method only works for indirect blocks - quit\n");
return;
}
debug(FS_UNIX, "resolveIndirectDataBlocks - indirect_block %x deg_of_indirection=%d\n", indirect_block, degree_of_indirection);
FileSystem* fs = inode->getFileSystem();
assert(fs != NULL);
FsVolumeManager* volume_manager = fs->getVolumeManager();
assert(volume_manager != NULL);
// lock sector for reading
volume_manager->acquireDataBlockForReading(indirect_block);
// readout sector data
char* sector = volume_manager->readDataBlockUnprotected(indirect_block);
// scan the current block for more indirect blocks
for(sector_len_t i = 0; i < fs->getDataBlockSize(); i+= sector_addr_len)
{
sector_addr_t new_sector = 0;
// reading the current sector entry in a very flexible way
for(uint16 j = 0; j < sector_addr_len; j++)
{
//debug(FS_UNIX, "resolveIndirectDataBlocks - sector[%d + %d]=%x\n", i, j, (uint8)sector[i + j]);
new_sector |= ((uint8)(sector[i + j])) << (8*j);
}
if(new_sector == UNUSED_DATA_BLOCK)
{
// from here on there are no more indirect blocks to resolve, we can quit
debug(FS_UNIX, "resolveIndirectDataBlocks - quit search for indirect blocks\n");
break;
}
debug(FS_UNIX, "resolveIndirectDataBlocks - new_sector=%x\n", new_sector);
// single-indirect block means that the gained (resolved) sector-address
// points to a data-block of the i_node
if(degree_of_indirection == 1)
{
inode->addSector(new_sector);
}
else
{
resolveIndirectDataBlocks(inode, new_sector, degree_of_indirection-1, sector_addr_len);
}
}
volume_manager->releaseReadDataBlock(indirect_block);
delete[] sector;
}
