fat_get_block
return mpage_writepages(mapping, wbc, fat_get_block);
return mpage_read_folio(folio, fat_get_block);
mpage_readahead(rac, fat_get_block);
foliop, fsdata, fat_get_block,
ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
return block_truncate_page(inode->i_mapping, from, fat_get_block);