[Bugme-new] [Bug 12555] New: Btrfs is a very UNSAFE Filesystem

[bugme-daemon at bugzilla.kernel.org]

http://bugzilla.kernel.org/show_bug.cgi?id=12555

           Summary: Btrfs is a very UNSAFE Filesystem
           Product: File System
           Version: 2.5
     KernelVersion: 2.6.28.2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: btrfs
        AssignedTo: fs_btrfs at kernel-bugs.osdl.org
        ReportedBy: v.quequet-techniques at orange.fr


Latest working kernel version: unknown
Earliest failing kernel version: 2.6.28.2
Distribution:
Hardware Environment:
Software Environment:

Explained kernel versions Descriptions:

I used both Linux 2.6.28.2 and 2.6.29-rc2-git3 .
With Linux2.6.28.2 , I used btrfs 0.17 provided by
  http://www.kernel.org/pub/linux/kernel/people/mason/btrfs/

Problem Description:

btrfs is still a wreck

Steps to reproduce:

In introduction, please read my 'cat /proc/partitions' output:

major minor  #blocks  name

   3        0   58605120 hda
   3        1   20024991 hda1
   3        2    1959930 hda2
   3        4          1 hda4
   3        5     497983 hda5
   3        6    8787523 hda6
   3        7   26274276 hda7
   3        8    1052226 hda8
 254        0    1959930 dm-0
 254        1     497983 dm-1
   7        0     393216 loop0

I will use /dev/hda8 for BTRFS-related experiments.

Beside creating a fresh-new btrfs filesystem and mounting is straightly,
using the following commands:
  dd bs=1M if=/dev/zero of=/dev/hda8
  mkfs.btrfs /dev/hda8
  mount /dev/hda8 /mnt/hda8

I have 2 test usecases :
  - Usecase A: Extract linux-2.6.29-rc2 to /mnt/hda8
  - Usecase B: Create an approx 400MB emty (zeroed-file) in the /mnt/hda8
directory

Usecase A consists in:
  ( cd /mnt/hda8 && tar -xzf
/home/testr/Custom_Builds/Pristine_Kernel/linux-2.6.29-rc2-git3.tar.gz )

Usecase B consists in:
  ( cd /mnt/hda8 && dd bs=1M count=400 if=/dev/zero of=./400MB.bin )

Reversed usecases would consist in :

Usecase A' consists in:
  rm -vRf /mnt/hda8/linux-2.6.29-rc2-git3

Usecase B' consists in:
  rm -v /mnt/hda8/400MB.bin

The problems I had to face were (Always from a scratch new btrfs-formatted
/dev/hda8 filesystem):

Going through usecase A, then through usecase B lead to a kernel Oops.
  --> Unable to unmount /mnt/hda8 either

Going through usecase B, then through usecase A didn't show out a bug ;
  then, reverting uses case A by trying to remove the kernel source
  directory lead to another kernel Oops.
  --> Unable to unmount /mnt/hda8 either

In hope my report will prove usefull.

Notabene: I am currently unable to providing meaningful log reports such as
syslog or dmesg.

Don't hesitate to ask me for such reports at v.quequet-techniques at orange.fr
if you feel necessary.

Sincerely,
Valentin QUEQUET


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