Re: mkfs.btrfs on 24 disks in parallel crashes kernel

[Li Zefan <lizf@cn.fujitsu.com>]

> So I think we're on the same page for this problem, I've posted a test patch to
> the bugzilla
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=650261
> 
> Basically we just need to setup a blank root/fs_info so it can be set in
> set_super, and then we use those blank structs in open_ctree.  Hopefully this
> works, if it does I'll post it to the list for wider review.
> 

You can reproduce the bug easily by this simple script:

# cat test.sh
#! /bin/sh

for ((; ;))
{
    mount $1 $2
    umount $2
}

Now run the test (I was using loop devices):

# ./test.sh /dev/loop1 /mnt1 &
# ./test.sh /dev/loop2 /mnt2

(You'll get exactly the same crash)