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* question about ext4 backup block group descriptors
@ 2019-01-31  8:07 Xiaoguang Wang
  2019-02-01  1:45 ` Andreas Dilger
  0 siblings, 1 reply; 3+ messages in thread
From: Xiaoguang Wang @ 2019-01-31  8:07 UTC (permalink / raw)
  To: linux-ext4

hi,

Anyone can help answer when ext4's backup block group descriptors are updated?
I had used blktrace to track the corresponding backup block group descriptor
block, but didn't find that any backup blocks were written.
Thanks in advance.

Regards,
Xiaoguang Wang

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: question about ext4 backup block group descriptors
  2019-01-31  8:07 question about ext4 backup block group descriptors Xiaoguang Wang
@ 2019-02-01  1:45 ` Andreas Dilger
  2019-02-01  3:08   ` Xiaoguang Wang
  0 siblings, 1 reply; 3+ messages in thread
From: Andreas Dilger @ 2019-02-01  1:45 UTC (permalink / raw)
  To: Xiaoguang Wang; +Cc: linux-ext4

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On Jan 31, 2019, at 1:07 AM, Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> wrote:
> 
> Anyone can help answer when ext4's backup block group descriptors are updated?
> I had used blktrace to track the corresponding backup block group descriptor
> block, but didn't find that any backup blocks were written.
> Thanks in advance.

The ext4 kernel code never updates the backup block group descriptors.  That is only
done by e2fsck.

Cheers, Andreas






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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: question about ext4 backup block group descriptors
  2019-02-01  1:45 ` Andreas Dilger
@ 2019-02-01  3:08   ` Xiaoguang Wang
  0 siblings, 0 replies; 3+ messages in thread
From: Xiaoguang Wang @ 2019-02-01  3:08 UTC (permalink / raw)
  To: Andreas Dilger; +Cc: linux-ext4

hi,

> On Jan 31, 2019, at 1:07 AM, Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> wrote:
>>
>> Anyone can help answer when ext4's backup block group descriptors are updated?
>> I had used blktrace to track the corresponding backup block group descriptor
>> block, but didn't find that any backup blocks were written.
>> Thanks in advance.
> 
> The ext4 kernel code never updates the backup block group descriptors.  That is only
> done by e2fsck.
I see, thanks very much.

Regards,
Xiaoguang Wang

> 
> Cheers, Andreas
> 
> 
> 
> 
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-02-01  3:08 UTC | newest]

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2019-01-31  8:07 question about ext4 backup block group descriptors Xiaoguang Wang
2019-02-01  1:45 ` Andreas Dilger
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