Subject: Re: [vserver] ext4 inode tagging
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Sun, 15 Jan 2012 02:47:15 +0100

On Sun, Jan 15, 2012 at 12:29:36AM +0100, Roberto Puzzanghera wrote:
> On 01/14/2012 11:14 AM, Herbert Poetzl wrote:
>> On Sat, Jan 14, 2012 at 09:47:19AM +0100, Roberto Puzzanghera wrote:
>>> On 01/14/2012 12:48 AM, Herbert Poetzl wrote:
>>>> On Fri, Jan 13, 2012 at 07:26:13PM +0100, Roberto Puzzanghera wrote:
>>>>> On 01/13/2012 06:02 PM, Herbert Poetzl wrote:
>>>>>> On Fri, Jan 13, 2012 at 05:10:46PM +0100, Roberto Puzzanghera wrote:
>>>>>>> [...]

>>>>>>>> no, I don't think that will be necessary, but
>>>>>>>> could you run the following script on your system
>>>>>>>> and provide upload the output somewhere/

>>>>>>>>  # mkdir /test
>>>>>>>>  # testfs.sh -vvv -x -F ext4 -M /test -D<device>

>>>>>>>> note that<device>     should be a partition, disk or
>>>>>>>> loopback device you do not mind to be reformatted
>>>>>>>> with ext4 (all data will be destroyed)

>>>>>>>> you can simply create one with:
>>>>>>>>  # dd if=/dev/zero of=/path/to/somewhere bs=1M count=1024
>>>>>>>>  # losetup /dev/loop0 /path/to/somewhere

>>>>>>>> also, no problem to use /mnt or /media/test instead
>>>>>>>> of just /test (i.e. it doesn't matter as long as
>>>>>>>> you specify the path in -M<path>)

>>>>>>>> the test script can be found here:
>>>>>>>> http://vserver.13thfloor.at/Stuff/SCRIPT/testfs.sh

>>>>> # dd if=/dev/zero of=/mnt/testfs bs=1M count=1024
>>>>> # losetup /dev/loop0 /mnt/testfs
>>>>> # mount -t ext4 /dev/loop0 /mnt/tmp/
>>>>> # testfs.sh -vvv -x -F ext4 -M /mnt/tmp/ -D /dev/loop0

>>>> do not mount any filesystem on /mnt/tmp and do not
>>>> mount or busy /dev/loop0 in any way, filesystem
>>>> creation and mounting will be done by testfs.sh

>>> The output follows

>>> best regards
>>> Roberto Puzzanghera


>>> # dd if=/dev/zero of=/usr/local/testfs bs=1M count=1024
>>> # losetup /dev/loop0 /usr/local/testfs
>>> # ./testfs.sh -vvv -x -F ext4 -M /mnt -D /dev/loop0
>>> Linux-VServer FS Test [V0.23] Copyright (C) 2005-2009 H.Poetzl
>>> Linux 3.1.4-vs2.3.2.1-smp x86_64/0.30.216
>>> VCI:  0002:0308 236 13000f11 (ID24)
>>> ---
>>> testing ext4 filesystem ...
>>> mke2fs 1.41.14 (22-Dec-2010)
>>> Filesystem label=
>>> OS type: Linux
>>> Block size=4096 (log=2)
>>> Fragment size=4096 (log=2)
>>> Stride=0 blocks, Stripe width=0 blocks
>>> 65536 inodes, 262144 blocks
>>> 13107 blocks (5.00%) reserved for the super user
>>> First data block=0
>>> Maximum filesystem blocks=268435456
>>> 8 block groups
>>> 32768 blocks per group, 32768 fragments per group
>>> 8192 inodes per group
>>> Superblock backups stored on blocks:
>>>         32768, 98304, 163840, 229376

>>> Writing inode tables: done
>>> Creating journal (8192 blocks): done
>>> Writing superblocks and filesystem accounting information: done

>>> This filesystem will be automatically checked every 24 mounts or
>>> 180 days, whichever comes first.  Use tune2fs -c or -i to override.
>>> [000]# succeeded.
>>>         mount -t ext4 -o rw /dev/loop0 /mnt 3>&2
>>> [001]# succeeded.
>>>         mount -o remount,rw,tag /mnt 3>&2
>>> mount: /mnt not mounted already, or bad option
>>> [002]# succeeded.
>>> tag related tests ...
>>>         mount -t ext4 -o rw,tag /dev/loop0 /mnt 3>&2
>>> [011]# succeeded.
>>>         do_tag_touch /mnt 0 1 255 256 666
>>>         touch /mnt/file_1: 0
>>>         vtag --migrate --tag 0 -- touch /mnt/file_1
>>>         touch /mnt/file_2: 1
>>>         vtag --migrate --tag 1 -- touch /mnt/file_2
>>>         touch /mnt/file_3: 255
>>>         vtag --migrate --tag 255 -- touch /mnt/file_3
>>>         touch /mnt/file_4: 256
>>>         vtag --migrate --tag 256 -- touch /mnt/file_4
>>>         touch /mnt/file_5: 666
>>>         vtag --migrate --tag 666 -- touch /mnt/file_5
>>> [012]# succeeded.
>>>         do_tag_verify /mnt 0 1 255 256 666
>>>         verify /mnt/file_1: 0 = 0
>>>         verify /mnt/file_2: 1 = 1
>>>         verify /mnt/file_3: 255 = 255
>>>         verify /mnt/file_4: 256 = 256
>>>         verify /mnt/file_5: 666 = 666
>>> [014]# succeeded.

>> this shows that tagging on ext4 works perfectly fine,
>> please verify (with 'cat /proc/mounts' on the host)
>> that your filesystem is indeed mounted with the 'tag'
>> option when you try to do tagging related operations

>> note: it was observed that, for yet unknown reasons,
>> sometimes the 'tag' option isn't used/recognized
>> despite the fact that it is present in host/guest
>> fstab ...

> I don't what I have missed before, but after rebooting the
> machine everything works perfectly: tagging, disk limits.

> I apologize for the noise in the list, at least I hope that my
> tests have shown that inode tagging is working with ext4 in the
> latest 3.1.4-vs2.3.2.1 kernel.

not convinced that it was just noise, but let's see
what we find out in the near future ...

thanks,
Herbert

> Best regards
> Roberto Puzzanghera


>> HTH,
>> Herbert