Re: Cloning a Btrfs partition

[BJ Quinn <bj@placs.net>]

Thanks for the response!  Not sure I want to roll a custom kernel on this
particular system.  Any idea on when it might make it to 3.10 stable or 
3.11?  Or should I just revert back to 3.9?

Thanks!

-BJ

----- Original Message ----- 

From: "Jan Schmidt" <list.btrfs@jan-o-sch.net> 
Sent: Monday, July 29, 2013 3:21:51 AM 

Hi BJ, 

[original message rewrapped] 

On Thu, July 25, 2013 at 18:32 (+0200), BJ Quinn wrote: 
> (Apologies for the double post -- forgot to send as plain text the first time 
> around, so the list rejected it.) 
> 
> I see that there's now a btrfs send / receive and I've tried using it, but 
> I'm getting the oops I've pasted below, after which the FS becomes 
> unresponsive (no I/O to the drive, no CPU usage, but all attempts to access 
> the FS results in a hang). I have an internal drive (single drive) that 
> contains 82GB of compressed data with a couple hundred snapshots. I tried 
> taking the first snapshot and making a read only copy (btrfs subvolume 
> snapshot -r) and then I connected an external USB drive and ran btrfs send / 
> receive to that external drive. It starts working and gets a couple of GB in 
> (I'd expect the first snapshot to be about 20GB) and then gets the following 
> error. I had to use the latest copy of btrfs-progs from git, because the 
> package installed on my system (btrfs-progs-0.20-0.2.git91d9eec) simply 
> returned "invalid argument" when trying to run btrfs send / receive. Thanks 
> in advance for any info you may have. 

The problem has been introduced with rbtree ulists in 3.10, commit 

Btrfs: add a rb_tree to improve performance of ulist search 

You should be safe to revert that commit, it's a performance optimization 
attempt. Alternatively, you can apply the published fix 

Btrfs: fix crash regarding to ulist_add_merge 

It has not made it into 3.10 stable or 3.11, yet, but is contained in Josef's 
btrfs-next 

git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git 

Thanks, 
-Jan