Bug 84631

Summary: Problem mounting btrfs-volume during boot
Product: File System Reporter: Eugene (ken20001)
Component: btrfsAssignee: Josef Bacik (josef)
Severity: blocking CC: jackdachef, yocto6
Priority: P1    
Hardware: Intel   
OS: Linux   
Kernel Version: 3.17RC5 Subsystem:
Regression: No Bisected commit-id:
Attachments: lsmod

Description Eugene 2014-09-15 15:33:51 UTC
Kubuntu 14.04.1 x86_64
Trying linux 3.17RC5 kernel I dicsovered that it can't mount /mnt/pool/main volume where all btrfs snaphots is. It writes that it can't mount /mnt/pool/main during boot and suggests to push S or M. Pushing S system continues to boot but after login I see clean installed OS. It seems it boots first btrfs snapshot.

Here is my partition table:

sda1: clean, 2MiB -bios_grub flag
sda2: linux-swap, 8GiB
sda3: btrfs, /,/home,/mnt/pool/main, the rest of size

Here is my /etc/fstab:

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sda3 during installation
UUID=b76fc0ae-d31c-4b13-8f4e-424542d850c9 /               btrfs   defaults,autodefrag,subvol=@ 0       1
# /home was on /dev/sda3 during installation
UUID=b76fc0ae-d31c-4b13-8f4e-424542d850c9 /home           btrfs   defaults,autodefrag,subvol=@home 0       2
# swap was on /dev/sda2 during installation
UUID=7f0a3747-8cd1-4806-9df4-918d8c15e119 none            swap    sw              0       0
#pool main
UUID=b76fc0ae-d31c-4b13-8f4e-424542d850c9 /mnt/pool/main       btrfs   defaults,autodefrag   0   2

#pool virt
UUID=6844bc41-95ff-4ec0-ac0b-690e4342fee5 /mnt/pool/virt       btrfs   defaults,autodefrag   0   2

# @libvirtimages
UUID=6844bc41-95ff-4ec0-ac0b-690e4342fee5 /var/lib/libvirt/images btrfs defaults,autodefrag,subvol=@libvirtimages  0   2

tmpfs /tmp tmpfs defaults,nodev,nosuid 0 0
Comment 1 Nicholas 2014-09-21 02:13:50 UTC
I don't known the btrfs code base that well yet to being new to this part of the kernel but I am going to email the list for btrfs devolopment with your fstab and
link to this page with your bug report/
Cheers and Thanks for the Report,
Comment 2 Matthew 2014-09-21 03:31:36 UTC

does the following commit (revert) help ?

Comment 3 Nicholas 2014-09-21 03:35:39 UTC
After reading the patch seems so from my reading. I would ask Eugene to test it through.
Regards Nick
Comment 4 Eugene 2014-09-21 13:46:12 UTC
I would like to test it. But the thing is I'm just a usual user and don't know how to compile kernel. So I don't know how to check that commit.
Comment 5 Nicholas 2014-09-22 01:30:56 UTC
Would you mind then allowing us to ssh into your system or teach you how to do this. Also what distro are you on for our knownledge too.
Comment 6 Eugene 2014-09-22 13:36:46 UTC
Of course I'm ready if you can teach me how to compile it. I'm using Kubuntu 14.04.1 x86_64.
Comment 7 Nicholas 2014-09-22 15:05:53 UTC
The basic steps are download the latest rc release for kernel.org.
Then extract it to any directory, afterwards run lsmod and please
sent the output so me can help you find the modules to build the
kernel correctly with your needed drivers.
Link to Latest Rc 
Download the Rc 6 Candiate
Comment 8 Eugene 2014-09-22 16:00:03 UTC
Created attachment 151301 [details]
Comment 9 Eugene 2014-09-22 17:31:59 UTC
Please see the attachment.
Comment 10 Eugene 2014-09-22 18:38:53 UTC
Strange thing but recently I booted my machine with RC6 and it seems without any problems. I'll test it a little more and write a reply here.
Comment 11 Nicholas 2014-09-22 18:57:59 UTC
Good Job on Compiling your Own Kernel ,
There was a regression you hitin Rc5 that is fixed in Rc6.
I will post the log below this message of the commit if 
you are interested in reading it.
Regards Nick 
Comment 12 Eugene 2014-09-22 19:27:09 UTC
Thanks but I didn't. I just download it from here: http://kernel.ubuntu.com/~kernel-ppa/mainline/. Firest I didn't understood you correctly: I thought I need to apply a patch by hand and then recompile a kernel. But since it was already applied by developers I don't need to do it by hand. Thanks again.

So the only pity thing is that I'll not learn how to compile a kernel.
Comment 13 Nicholas 2014-09-22 19:35:32 UTC
Would you mind closing this bug as to clear up the kernel bugzilla a bit?
Thanks Again Nick
Comment 14 Eugene 2014-09-22 19:58:41 UTC
Done. Another time someone will learn me how to compile a kernel. :)