On 2015-10-05 10:19, Austin S Hemmelgarn wrote:
> On 2015-10-05 09:14, Hugo Mills wrote:
>> On Mon, Oct 05, 2015 at 08:30:17AM -0400, Austin S Hemmelgarn wrote:
>>> I've been having issues recently with a relatively simple setup
>>> using a two device BTRFS raid1 on top of two two device md RAID0's,
>>> and every time I've rebooted since starting trying to use this
>>> particular filesystem, I've found it unable to mount and had to
>>> recreate it from scratch.  This is more of an inconvenience than
>>> anything else (while I don't have backups of it, all the data is
>>> trivial to recreate (in fact, so trivial that doing backups would be
>>> more effort than just recreating the data by hand)), but it's still
>>> something that I would like to try and fix.
>>>
>>> First off, general info:
>>> Kernel version: 4.2.1-local+ (4.2.1 with minor modifications,
>>> sources can be found here: https://github.com/ferroin/linux)
>>> Btrfs-progs version: 4.2
>>>
>>> I would post output from btrfs fi show, but that's spouting
>>> obviously wrong data (it's saying I'm using only 127MB with 2GB of
>>> allocations on each 'disk',  I had been storing approximately 4-6GB
>>> of actual data on the filesystem).
>>>
>>> This particular filesystem is composed of BTRFS raid1 across two LVM
>>> managed DM/MD RAID0 devices, each of which spans 2 physical hard
>>> drives.  I have a couple of other filesystems with the exact same
>>> configuration that have not ever displayed this issue.
>>>
>>> When I run 'btrfs check' on the filesystem when it refuses to mount,
>>> I get a number of lines like the following:
>>> bad metadata [<bytenr>, <bytenr>) crossing stripe boundary
>>>
>>> followed eventually by:
>>> Errors found in extent allocation tree or chunk allocation
>>
>>     I _think_ this is a bug in mkfs from 4.2.0, fixed in later
>> releases of the btrfs-progs.
> If so, that's good news (that is, that it's just a mkfs bug).  I guess
> it's time for me to quit waiting around for Gentoo to package the newest
> version and build it myself.
It looks like it was indeed a bug in mkfs from 4.2.0, I upgraded to the 
development branch and everything seems to be working correctly now. 
Thanks for the help!