Re: Btrfs-progs release 3.17

[Anand Jain <Anand.Jain@oracle.com>]

  there is no point in re-creating so many btrfs kernel's logic in user
  space. its just unnecessary, when kernel is already doing it. use
  some interface to get info from kernel after device is registered,
  (not necessarily mounted). so progs can be as sleek as possible.
  to me it started as just one more bug now we have fixed so many many.
  It all needs one good interface for kernel which provides anything
  anything from the kernel.



On 10/23/14 16:52, Gui Hecheng wrote:
> On Thu, 2014-10-23 at 16:13 +0800, Anand Jain wrote:
>>
>> Some of the disks on my system were missing and I was able to hit
>> this issue.
>>
>>
>> ----------------
>> Check tree block failed, want=12582912, have=0
>> read block failed check_tree_block
>> Couldn't read chunk root
>> warning devid 2 not found already
>> Check tree block failed, want=143360, have=0
>> read block failed check_tree_block
>> Couldn't read chunk root
>> warning, device 4 is missing
>> warning, device 3 is missing
>> warning, device 2 is missing
>> warning, device 1 is missing
>> ----------------
>>
>>
>> Did a bisect and it leads to this following patch.
>>
>> ----------------
>> commit 915902c5002485fb13d27c4b699a73fb66cc0f09
>>
>>       btrfs-progs: fix device missing of btrfs fi show with seed devices
>> ----------------
>>
>>    Also this patch stalls ~2sec in the cmd btrfs fi show, on my system
>>    with 48 disks.
>>
>> Also a simple test case hits some warnings...
>>
>> ----------------
>>    mkfs.btrfs -draid1 -mraid1 /dev/sdb /dev/sdc
>>    mount /dev/sdb /btrfs && fillfs /btrfs 100 && umount /btrfs
>>    wipefs -a /dev/sdb
>>    modprobe -r btrfs && modprobe btrfs
>>    mount -o degraded /dev/sdb /btrfs
>>    btrfs fi show
>> Label: none  uuid: 9844cd05-1c8c-473e-a84b-bac95aab7bc9
>>           Total devices 2 FS bytes used 1.59MiB
>>           devid    2 size 967.87MiB used 104.75MiB path /dev/sdc
>>           *** Some devices missing
>>
>> warning, device 1 is missing
>> warning, device 1 is missing
>> warning devid 1 not found already
>> ----------------
>>
>
> Hi Anand and Petr,
>
> Oh, it seems that there are btrfs with missing devs that are bringing
> troubles to the @open_ctree_... function.
> This should be a missing case of the patch above which should only take
> effects when seeding devices are present.
> I will try my best to follow this case, suggestions are welcome, Thanks!
>
> -Gui
>
>>
>>
>>
>> On 10/23/14 14:57, Petr Janecek wrote:
>>> Hello,
>>>
>>>>    You have mentioned two issues when balance and fi show running
>>>>    concurrently
>>>
>>>     my mail was a bit chaotic, but I get the stalls even on idle system.
>>> Today I got
>>>
>>> parent transid verify failed on 1559973888000 wanted 1819 found 1821
>>> parent transid verify failed on 1559973888000 wanted 1819 found 1821
>>> parent transid verify failed on 1559973888000 wanted 1819 found 1821
>>> parent transid verify failed on 1559973888000 wanted 1819 found 1821
>>> Ignoring transid failure
>>> leaf parent key incorrect 1559973888000
>>>
>>> from 'btrfs fi sh' while I was just copying something, no balance running.
>>>
>>> [...]
>>>> [PATCH 1/1] btrfs-progs: code optimize cmd_scan_dev() use
>>>> btrfs_register_one_device()
>>>> [PATCH 1/2] btrfs-progs: introduce btrfs_register_all_device()
>>>> [PATCH 2/2] btrfs-progs: optimize btrfs_scan_lblkid() for multiple calls
>>>>
>>>> If you could, pls..
>>>>    Now on 3.17 apply above 3 patches and see if you see any better
>>>>    performance for the stalling issue.
>>>
>>>     no perceptible change: takes ~40 seconds both before and after
>>> applying. Old version <1 sec.
>>>
>>>>    can you do same steps on 3.16 and report what you observe
>>>
>>>     So many rejects -- do you have older versions of these patches?
>>>
>>>
>>> Thanks,
>>>
>>> Petr
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>
>
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