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: Tue, 21 Jun 2022 17:46:53 +0200 [thread overview]
Message-ID: <20220621154653.GA10068@lst.de> (raw)
In-Reply-To: <b633dedf-b322-2d8c-adfb-8ab88af5652e@suse.com>
On Tue, Jun 21, 2022 at 06:19:19PM +0300, Nikolay Borisov wrote:
>> +
>> + mirror = failrec->this_mirror;
>> + do {
>> + mirror = prev_mirror(failrec, mirror);
>> + repair_io_failure(fs_info, ino, start, failrec->len,
>> + failrec->logical, page, pg_offset, mirror);
>> + } while (mirror != failrec->orig_mirror);
>
> But does this work as intended? Say we have a raid1c4 and we read from
> mirror 3 which is bad, in this case failrec->orig_mirror = 3 and
> ->this_mirror = 4. The read from mirror 4 returns good data and
> clean_io_failure is called with mirror= 3 in which case only mirror 3 is
> repaired (assume 1/2 were also bad we don't know it yet, because the
> original bio request didn't submit to them based on the PID policy).
Yes. Although that is what I intended as we don't want to read
data we don't otherwise have to. Maybe it should state "all known bad
mirrors" instead of "all mirrors". I think if we want to check all
mirror we need to defer to the scrub code.
next prev parent reply other threads:[~2022-06-21 15:46 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 [this message]
2022-06-21 17:49 ` Nikolay Borisov
2022-06-22 4:23 ` Christoph Hellwig
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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