~~~~~~~~~~~~~~~~ I checked for ext4-users mailing list - but unable to find it and posted this question to ext4-beta-list at redhat.com - It's seems like that mailing list is less active.So I'm posting it again to ext3 list . ~~~~~~~~~~~~~~~~ I was accessing ext4 file using ext2fs lib (from e2fsprogs-1.41.9-Fedora 12 ) ,while parsing inode contents I got these output Let me know whether my assumptions are correct? --------------- //code-part : print inode values ext2fs_read_inode(current_fs,d->d_ino,&inode); for ( i = 0; i < 15; i++) printf ("\ni_block[%d] :%u", i, inode.i_block[i]); --------------- In struct ext4_inode i_block[EXT4_N_BLOCKS], i_block[0] to i_block[2] denotes extent headers and tells whether this inode uses Htree for storing files data blocks. //output i_block[0] :324362 i_block[1] :4 i_block[2] :0 //remaining i_block[3] to i_block[14] holds four extents ?in following format //{extent index,number of blocks in extents,starting block number} i_block[3] :0 ? ? ? ? ? // --> first extent denoted as 0 i_block[4] :1 ? ? ? ? ? // --> has single block i_block[5] :36890 ? ? ? // --> block number is 36890 i_block[6] :1 ? ? ? ? ? // --> second extent denoted as 1 i_block[7] :2 ? ? ? ? ? // --> has two blocks i_block[8] :36892 ? ? ? // --> it uses 36892 and 36893 i_block[9] :3 ? ? ? ? ? // --??--> third extent ?-- why is it numbered as 3 instead of 2? i_block[10] :2 ? ? ? ? ?// --> has two blocks i_block[11] :36898 ? ? ?// --> uses 36898 and 36899 i_block[12] :5 ? ? ? ? ?// --??--> fourth and finally extent -- again why its comes as 5 instead of 3. i_block[13] :11 ? ? ? ? // --> it uses 11 blocks i_block[14] :38402 ? ? ?// --> starting block is 38402. If my assumption are correct,the question is ,why i_block[9] ?shows 3 instead of 2 and ? i_block[12] says 5 instead of 3? Thanks. -- ---- Cheers, Lakshmipathi.G www.giis.co.in