BTRFS 0.17 in rawhide (at some point)

[Eric Sandeen]

Rahul Sundaram wrote:
> Kevin Kofler wrote:
>> One question I couldn't find a definite answer to: Does btrfs-convert also
>> work on ext4? In other words: Can we upgrade from ext3 to ext4 and then
>> from ext4 to btrfs? Or are we painting ourselves in a corner by using ext4?
> 
> I asked this question to Eric Sandeen earlier on IRC and Chris Mason has 
> confirmed that it should work. Someone probably needs to test that however.
> 
> Besides, Btrfs is probably going to take a couple more releases before 
> it gets to the stage where we can trust it enough to use it as default 
> and Ext4 provides us good advantages meanwhile.

It does basically work; the ext4 snapshot is bloated because the tool
doesn't understand uninitialized ext4 block groups, but that's just a
detail.  (But yes, I did test this).

Because the tool was properly written to use libext2fs, ext4 should
"just work" (modulo some little kinks like above).  :)

-Eric