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From: Christoph Hellwig <hch@lst.de>
To: Nikolay Borisov <nborisov@suse.com>
Cc: Christoph Hellwig <hch@lst.de>,
	clm@fb.com, josef@toxicpanda.com, dsterba@suse.com,
	linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: repair all bad mirrors
Date: Wed, 22 Jun 2022 06:23:35 +0200	[thread overview]
Message-ID: <20220622042335.GB21099@lst.de> (raw)
In-Reply-To: <3971f947-aeec-98c0-dca1-a90016f67dd5@suse.com>

On Tue, Jun 21, 2022 at 08:49:09PM +0300, Nikolay Borisov wrote:
>
> My point is won't this loop ever fix at most 1 mirror? Consider again 
> raid1c4, where the 4th copy is the good one. First we read from 0 -> bad we 
> submit io to mirror 1 (orig_mirror = 0, this_mirror=1). The same thing is 
> repeated until we get to orig_mirror = 3, this_mirror =4. This time the 
> repair would be completed and so for this_mirror = 4 we'll execute 
> clean_io_failure in which case the do{} while() loop will only fix the bad 
> copy for mirror 3.

For this case ->orig_mirror is set to 0 if that was the first bad mirror.
The do {} while loop then walks back until it repaired org_mirror, tha
s 0, and breaks after that.  The impotant bit is that unlike in the code
before this patch orig_mirror/failed_mirror is not reset for every new failure.

  reply	other threads:[~2022-06-22  4:24 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-19  8:28 [PATCH] btrfs: repair all bad mirrors Christoph Hellwig
2022-06-21 15:19 ` Nikolay Borisov
2022-06-21 15:46   ` Christoph Hellwig
2022-06-21 17:49     ` Nikolay Borisov
2022-06-22  4:23       ` Christoph Hellwig [this message]
2022-06-22  4:32 ` Qu Wenruo
2022-06-22  5:06   ` Christoph Hellwig
2022-06-22  5:14     ` Qu Wenruo
2022-06-22  7:47       ` Christoph Hellwig
2022-06-22  8:46         ` Qu Wenruo
2022-06-22 11:02           ` Christoph Hellwig

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