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NetBSD-SoC: Improve and Extend resize_ffs

Project Description

The utility resize_ffs is a program intended to resize Berkeley Fast File Systems (FFS) by either growing or shrinking them. This filesystem is the standard filesystem for the NetBSD operating system -- a free, fast, secure, and highly portable Unix-like Open Source operating system.

There is already a preliminary utility in the NetBSD source tree, and this project will first and primarily thoroughly test it with a regression test suite and code review, and correct and fix any bugs encountered. After this is accomplished, and the utility is stable, this project will attempt to extend the utility with features such as "live" resizing, that is the ability to dynamically resize the filesystem without first having to unmount it.

Status

Google Summer of Code 2009: Program Timeline

You can view the CVS respository here. You can also download the respository module with:

$ cvs -d:pserver:anonymous@netbsd-soc.cvs.sourceforge.net:/cvsroot/netbsd-soc checkout -P resize_ffs

Feel free to use and test the utility and provide feedback here.

Updates

May 23, 2009

• Official Start of Coding

June 30, 2009

• After a bit of a slow start, the project is back on track. I am moving from the "just testing" phase to using that test information to hunt down bugs and also improve the program.
• One addition I have already added is the ability to choose the new filesystem size in kilo-, mega-, or gigabytes - as well as the default of sectors. However, it does currently assume a sector size of 512 KB in the conversion.
• I have several potential bugs:
  • After shrinking, fsck complains about:
    • FREE BLK COUNT(S) WRONG IN SUPERBLK
    • SUMMARY INFORMATION BAD
    • BLK(S) MISSING IN BIT MAPS
    This is a consistent error. A similar error occurs during growing, but it seems limited to only producing bad summary information.
  • Segmentation fault during shrinking. This is intermittent and appears to be related to the above bug.
  • During growing, data can become corrupt. This is intermittent and I have not yet detected any apparent pattern to why or when this will occur.

Deliverables

[What exactly is intended to be provided by this project. This list will be used to judge the success of the project!]

Mandatory (must-have) components:

• regression test-suite
• stable version of resize_ffs

Optional (would-be-nice) components:

• port to FFSv2
• "live" resizing
• defragmentation option

Documentation

[Insert use and test cases, instruction for integration into NetBSD, installation, configuration, using; reference existing standards or other existing works where appropriate]

Documentation for this project

• MANPAGE: resize_ffs(8)
• README
• TODO
• CHANGELOG

Resources that were helpful to me

• Books
  • The Design and Implementation of the 4.4 BSD Operating System
  • Introducing Software Testing
  • Good desktop references:
    • The C Programming Language
    • Unix Shell Programming
• Web Resources
  • The NetBSD Guide
  • hubertf's NetBSD Blog -- March 31, 2008: Catching up: portability, mult, Freescale i.mx31, fortunes, growfs, SMP, IIJ SEIL/X
• Manpages
  • fsck(8)
  • fsck_ffs(8)

Technical Details

[Documentation of existing NetBSD interfaces used, new interfaces created, pointers to header-files, section .2/.3/.9 manpages created and used, etc.]

Christopher Berardi $Id: index.html,v 1.7 2009/06/30 18:56:30 cberardi Exp $