[Bug 1515510] [NEW] btrfs device delete crashes system

[Thomas]

Public bug reported:

I try to delete a disk from a BTRFS in RAID-10 mode. (not on top of RAID-10)
At random time the whole system simply holds in between of this operation. All the drives are attached to SATA-6/3 ports. Unfortunately there is absolutely nothing in the log before the crash (kernel.log)
During delete operation the cash memory increases steadily but this might be normal?! For this I have attached a screenshot.
The crash happened multiple times for two drives now. 
I can delete drives from crash to crash, the crash is random, sometime btrfs frees several hundred GB without problems, so I can delete a drive finally. 
If there is anything I can do to help debug this, please let me know and I start over again. 

This is what kernel.log says before the crash.

Nov 10 23:33:29 next kernel: [55671.766021] BTRFS info (device sda2): found 61 extents
Nov 10 23:33:30 next kernel: [55672.510210] BTRFS info (device sda2): relocating block group 2848171491328 flags 65
Nov 10 23:34:00 next kernel: [55702.661005] BTRFS info (device sda2): found 18331 extents
Nov 10 23:34:09 next kernel: [55712.079897] BTRFS info (device sda2): found 18331 extents
Nov 10 23:34:10 next kernel: [55712.999124] BTRFS info (device sda2): relocating block group 5085916561408 flags 65
Nov 10 23:34:38 next kernel: [55740.998170] BTRFS info (device sda2): found 9116 extents
Nov 10 23:34:51 next kernel: [55753.269616] BTRFS info (device sda2): found 9116 extents
Nov 10 23:34:51 next kernel: [55753.958786] BTRFS info (device sda2): relocating block group 4207595749376 flags 65

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: btrfs-tools 4.0-2
ProcVersionSignature: Ubuntu 4.2.0-17.21-generic 4.2.3
Uname: Linux 4.2.0-17-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.1-0ubuntu4
Architecture: amd64
Date: Thu Nov 12 08:44:43 2015
InstallationDate: Installed on 2012-10-15 (1122 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121014)
SourcePackage: btrfs-tools
UpgradeStatus: Upgraded to wily on 2015-11-02 (9 days ago)

** Affects: btrfs-tools (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug wily

** Attachment added: "memory-day.png"
   https://bugs.launchpad.net/bugs/1515510/+attachment/4517400/+files/memory-day.png

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to btrfs-tools in Ubuntu.
https://bugs.launchpad.net/bugs/1515510

Title:
  btrfs device delete crashes system

Status in btrfs-tools package in Ubuntu:
  New

Bug description:
  I try to delete a disk from a BTRFS in RAID-10 mode. (not on top of RAID-10)
  At random time the whole system simply holds in between of this operation. All the drives are attached to SATA-6/3 ports. Unfortunately there is absolutely nothing in the log before the crash (kernel.log)
  During delete operation the cash memory increases steadily but this might be normal?! For this I have attached a screenshot.
  The crash happened multiple times for two drives now. 
  I can delete drives from crash to crash, the crash is random, sometime btrfs frees several hundred GB without problems, so I can delete a drive finally. 
  If there is anything I can do to help debug this, please let me know and I start over again. 

  This is what kernel.log says before the crash.

  Nov 10 23:33:29 next kernel: [55671.766021] BTRFS info (device sda2): found 61 extents
  Nov 10 23:33:30 next kernel: [55672.510210] BTRFS info (device sda2): relocating block group 2848171491328 flags 65
  Nov 10 23:34:00 next kernel: [55702.661005] BTRFS info (device sda2): found 18331 extents
  Nov 10 23:34:09 next kernel: [55712.079897] BTRFS info (device sda2): found 18331 extents
  Nov 10 23:34:10 next kernel: [55712.999124] BTRFS info (device sda2): relocating block group 5085916561408 flags 65
  Nov 10 23:34:38 next kernel: [55740.998170] BTRFS info (device sda2): found 9116 extents
  Nov 10 23:34:51 next kernel: [55753.269616] BTRFS info (device sda2): found 9116 extents
  Nov 10 23:34:51 next kernel: [55753.958786] BTRFS info (device sda2): relocating block group 4207595749376 flags 65

  ProblemType: Bug
  DistroRelease: Ubuntu 15.10
  Package: btrfs-tools 4.0-2
  ProcVersionSignature: Ubuntu 4.2.0-17.21-generic 4.2.3
  Uname: Linux 4.2.0-17-generic x86_64
  NonfreeKernelModules: nvidia
  ApportVersion: 2.19.1-0ubuntu4
  Architecture: amd64
  Date: Thu Nov 12 08:44:43 2015
  InstallationDate: Installed on 2012-10-15 (1122 days ago)
  InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121014)
  SourcePackage: btrfs-tools
  UpgradeStatus: Upgraded to wily on 2015-11-02 (9 days ago)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/btrfs-tools/+bug/1515510/+subscriptions