Re: 2.6.23.1: mdadm/raid5 hung/d-state

Justin Piszcz
2007-11-08T12:44:48Z

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On Thu, 8 Nov 2007, BERTRAND Joël wrote:

> BERTRAND Joël wrote:
>> Chuck Ebbert wrote:
>>> On 11/05/2007 03:36 AM, BERTRAND Joël wrote:
>>>> Neil Brown wrote:
>>>>> On Sunday November 4, jpiszcz@lucidpixels.com wrote:
>>>>>> # ps auxww | grep D
>>>>>> USER PID %CPU %MEM VSZ RSS TTY STAT START TIME
>>>>>> COMMAND
>>>>>> root 273 0.0 0.0 0 0 ? D Oct21 14:40
>>>>>> [pdflush]
>>>>>> root 274 0.0 0.0 0 0 ? D Oct21 13:00
>>>>>> [pdflush]
>>>>>>
>>>>>> After several days/weeks, this is the second time this has happened,
>>>>>> while doing regular file I/O (decompressing a file), everything on
>>>>>> the device went into D-state.
>>>>> At a guess (I haven't looked closely) I'd say it is the bug that was
>>>>> meant to be fixed by
>>>>>
>>>>> commit 4ae3f847e49e3787eca91bced31f8fd328d50496
>>>>>
>>>>> except that patch applied badly and needed to be fixed with
>>>>> the following patch (not in git yet).
>>>>> These have been sent to stable@ and should be in the queue for 2.6.23.2
>>>> My linux-2.6.23/drivers/md/raid5.c contains your patch for a long
>>>> time :
>>>>
>>>> ...
>>>> spin_lock(&sh->lock);
>>>> clear_bit(STRIPE_HANDLE, &sh->state);
>>>> clear_bit(STRIPE_DELAYED, &sh->state);
>>>>
>>>> s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
>>>> s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
>>>> s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
>>>> /* Now to look around and see what can be done */
>>>>
>>>> /* clean-up completed biofill operations */
>>>> if (test_bit(STRIPE_OP_BIOFILL, &sh->ops.complete)) {
>>>> clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
>>>> clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
>>>> clear_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
>>>> }
>>>>
>>>> rcu_read_lock();
>>>> for (i=disks; i--; ) {
>>>> mdk_rdev_t *rdev;
>>>> struct r5dev *dev = &sh->dev[i];
>>>> ...
>>>>
>>>> but it doesn't fix this bug.
>>>>
>>>
>>> Did that chunk starting with "clean-up completed biofill operations" end
>>> up where it belongs? The patch with the big context moves it to a
>>> different
>>> place from where the original one puts it when applied to 2.6.23...
>>>
>>> Lately I've seen several problems where the context isn't enough to make
>>> a patch apply properly when some offsets have changed. In some cases a
>>> patch won't apply at all because two nearly-identical areas are being
>>> changed and the first chunk gets applied where the second one should,
>>> leaving nowhere for the second chunk to apply.
>>
>> I always apply this kind of patches by hands, and no by patch command.
>> Last patch sent here seems to fix this bug :
>>
>> gershwin:[/usr/scripts] > cat /proc/mdstat
>> Personalities : [raid1] [raid6] [raid5] [raid4]
>> md7 : active raid1 sdi1[2] md_d0p1[0]
>> 1464725632 blocks [2/1] [U_]
>> [=====>...............] recovery = 27.1% (396992504/1464725632)
>> finish=1040.3min speed=17104K/sec
>
> Resync done. Patch fix this bug.
>
> Regards,
>
> JKB
>

Excellent!

I cannot easily re-produce the bug on my system so I will wait for the
next stable patch set to include it and let everyone know if it happens
again, thanks.