Topic: include 'fstransform'?


I am the author of 'fstransform' (http://sf.net/projects/fstransform/) a program to non-destructively change the contents of a partition from one file-system type to another, in-place and without the need for any backup.

The program is still in beta stage and surely needs more thorough testing, but it's already usable - on Linux I have tested it on ext2, ext3, ext4, jfs, reiserfs and xfs.

Except for 'convertfs', which looks abandoned since 2005, I am not aware of any other tool with similar features.

In _extreme_ summary, fstransform uses this technique to change the file-system inside a partition while preserving all contaned files, directories, etc.: creates a sparse file as large as the device, formats it (mkfs) with the target file-system type, mounts it as a loop device (losetup), moves one by one all the files inside it, finally remaps the file onto the partition.

On the plus side, it needs no knowledge of file-systems implementation details: it only needs the initial file-system to support sparse files and ioctl(FS_IOC_FIEMAP) or the older ioctl(FIBMAP).

On the down side, it is relatively slow: on a fast magnetic disk, transforming a 250GB file-system may take up to 10 hours.

I am proposing to add support to gparted to detect and launch fstransform as an external tool, and I can implement personally the required patches,
but I am new to gparted and I must admit I don't know if such tool can be considered in scope for gparted - personally, I would consider it a nice addition, but I am obviously biased...


Massimiliano Ghilardi


Re: include 'fstransform'?

Hi Massimiliano,

Thank you for your interest in GParted.  The fstransform tool you have developed sounds very promising indeed.

Your offer to add support to GParted for fstransform is in alignment with the GParted Mission Statement and we would certainly consider such an enhancement.

To help track the work on an fstransform enhancement, please create a new enhancement bug report for the GParted application.

For background information we had considered support for convertfs in the past, but as you point out the convertfs tool is no longer actively developed.
See Bug 353065 - convert partitions from between filesystems and other advanced features

If you have questions or concerns, please feel free to ask.  Also see the development page to learn more about GParted development.

Curtis Gedak


Re: include 'fstransform'?

Deal smile

Working as a programmer for non-free software, I can work on this task only in my spare time, so I will need a few weeks as minimum.

And yes, I will surely have some questions when I actually start.


Re: include 'fstransform'?

Thanks for the heads up on time frame.  There is no hard deadline from the GParted project side.  We fix bugs and add new features as the code becomes available.  As volunteers we only work when we have free time and the inclination to improve the code.  :-)

5 (edited by cosmos72 2012-03-10 19:50:03)

Re: include 'fstransform'?

As per your indications, I opened a gparted "enhancement bug report" on gnome Bugzilla - please see Bug 671784.

I also added cross-references between Bug 353065 you mentioned and this new enhancement Bug 671784.

The "gparted hacking session" I did was surprisingly productive: I have an initial patch that, although probably a bit too invasive, is well ahead of schedule. I will refine and post it for review in a few days.


Re: include 'fstransform'?

The first version of my patch is available as attachment in Bug 671784.

It still has some shortcomings and rough edges I would like to discuss - in other words, I have some questions.

At the moment, my questions are in the comments for Bug 671784. Is it better to discuss them here or there?


Re: include 'fstransform'?

Now that you have created the bug report it is best to track all development questions and patches in the bug report.

I have several tasks that I must attend to first, but should be able to look at your patch sometime this week.