On 2015-11-24 12:06, Vincent Olivier wrote:
> Hi,
>
> Woke up this morning with a kernel panic (for which I do not have details). Please find below the output for btrfs check. Is this normal ? What should I do ? Arch Linux 4.2.5. Btrfs-utils 4.3.1. 17x4TB RAID10.
You get bonus points for being on a reasonably up-to-date kernel and 
userspace :)

This is actually a pretty tame check result for a filesystem that's been 
through kernel panic. I think everything listed here is safe for check 
to fix, but I would suggest waiting until the devs provide opinions 
before actually running with --repair.  I would also suggest comparing 
results between the different devices in the FS, if things are 
drastically different, you may have issues that check can't fix on it's own.
> [root@3dcpc5 ~]# btrfs check /dev/sdk
> Checking filesystem on /dev/sdk
> UUID: 6a742786-070d-4557-9e67-c73b84967bf5
> checking extents
> checking free space cache
> checking fs roots
These next two lines are errors, but I'm not 100% certain if it's safe 
to have check fix them:
> root 5 inode 1341670 errors 400, nbytes wrong
> root 11406 inode 1341670 errors 400, nbytes wrong
This next one is also an error, and I am fairly certain that it's safe 
to have check fix as long as the number at the end is not too big.
> found 19328809638262 bytes used err is 1
The rest is just reference info
> total csum bytes: 18849042724
> total tree bytes: 27389886464
> total fs tree bytes: 4449746944
> total extent tree bytes: 3075457024
> btree space waste bytes: 2880474254
The only other thing I know that's worth mentioning is that if the 
numbers on these next two lines don't match, you may be missing some 
writes from right before the crash.
> file data blocks allocated: 19430708535296
> referenced 20123773407232