Hi all!

There have been quite some articles and posts about the Btrfs file system lately. It seems to be gaining a lot of momentum and adoption in Linux distributions.

Now my question is: How about the MS Windows support?

I still have two or three Windows versions on my computers in dual-boot configuration (in addition to running VirtualBox, which is quite a nice solution). Accessing files from both Linux and Windows operating systems has become quite difficult over the past few years. There are three feasible solutions I know of:

1. FAT32 - Has been supported in Linux for decades now and is the de-facto standard on USB storage devices. Big limitations: File size, case insensitivity and access rights. Though the latter is not really important on USB sticks. Aside from that, it's obsolete...

2. NTFS - With the ntfs-3g driver it works quite nicely out of the box on most Linux distributions now. However, the support is still based on reverse engineering. File size limits are no longer a problem, but the access permissions just don't map between the two worlds and case is also still an issue. I personally don't trust the Windows security implementation as much as the traditional UNIX access rights (in conjunction with ACLs nowadays). And even if it were mappable, there seems to be no documentation about the security models within NTFS.

3. ext2/3/4 - This is what I have been using the last couple of years for any dual-boot configuration. There is the Windows Ext2 IFS driver which also supports ext3 to some extent. Big problems: No journalling on ext3 and it does not support inode sizes > 128 bytes. For some time now, the default inode size when creating ext3 file systems has been 256 bytes. So even if one manages to create a separate data partition and format it to ext3, it's not trivial to figure out why it doesn't work with Ext2 IFS. Or even to know what an inode size is and how to tell mke2fs the right one to use. Having copied Gigabytes of data to the new FS and then noticing the only way to access it from Windows is re-formatting, that's a no-go for inexperienced users wanting to switch to a Linux distribution (like my Dad did, fortunately). The Ext2 IFS project looks rather dead, the last release is 1,5 years old and there don't seem to be any plans concerning these limitations. Not even to mention ext4 support. I am aware of a few commercial ext2/3/4 drivers for Windows, but aside from the licensing, the architecture doesn't seem as sane as with Ext2 IFS.

Enter Btrfs.

With it having a chance to be the default file system in many upcoming distro releases, this is another step further away from Windows / Linux filesystem compatibility. Ext4 as the current default is not an option either, but with the current developments, I would think a nice Btrfs driver would be the better way to go.

This is all not just concerning dual-boot configurations, but think USB mass storage devices? Having a small FAT32 partition with an installable driver and a large Btrfs data partition on a USB hard disk would be sufficient to use it in different environments where so far the only options were FAT and NTFS. Provided one has administrative rights on the Windows boxes

Maybe there is potential here for an article questioning the future plans, if anybody has any?

Kind regards and thanks Michael for all the nice posts and stories!
Andre