Last update: Wednesday, May 8th 2019
Document Updated!
When I was working at my first ext2 driver implementation, I found myself short of documentation on the subject. It wasn't so much the information not being available as of it not being available all in one place.
This project tries to fix this, by bringing in one single place all the useful information in one easy to understand package. I try to not tie the documentation to any particular operating system, so that it may be useful to the widest audience.
Change Log
February 4th, 2011Fixed typography in EXT2_SECRM_FL description Clarification to s_log_block_size Corrections to s_mnt_count and s_max_mnt_count Removed dead link to htree performance graph and replaced with link to paper by Daniel Phillips
February 1st, 2011Updated the EXT2_*_FL values
October 3rd, 2010Updated sample disk layouts Clarified location of the superblock Updated i_blocks definition in section 3.5.10
February 9th, 2009Updated i_blocks definition
August 5th, 2002Rewrote & updated most sections Indexed directories still need updates
August 2nd, 2002Added a note to .i_blocks and .i_dtime
July 31st, 2002Updated the values of EXT2_S_IFLNK and EXT2_S_IFSOCK as noted by Jeremy Stanley of AccessData Inc Added a note about the reserved inode entries
June 16th, 2002Fixed the 0 and 1 definitions for the block and inode bitmaps.
April 1st, 2002Cleared up the confusion about the location of the group descriptors in section 'Group Descriptor'
March 31st, 2002Added the description of EXT2_INDEX_FL (Hash Indexed Directory) Fixed many table layouts
March 25th, 2002Added the Indexed Directory Format Added .i_flags descriptions Added a collaborator section and a credits appendix Added some notes for compat/incompat features Completed the inode chapter
Added extended attributes