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

["BERTRAND Joël" <joel.bertrand@systella.fr>]

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
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