Commit c0b32972 authored Apr 24, 2013 by NeilBrown

md/raid5: avoid an extra write when writing to a known-bad-block.



If we write to a known-bad-block it will be flags as having
a ReadError by analyse_stripe, but the write will proceed anyway
(as it should).  Then the read-error handling will kick in an
write again, then re-read.

We don't need that 'write-again', so set R5_ReWrite so it looks like
it has already been done.  Then we will just get the re-read, which we
want.

Reported-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

parent 6f608040

drivers/md/raid5.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -1887,8 +1887,15 @@ static void raid5_end_write_request(struct bio *bi, int error)
		&rdev->mddev->recovery);
		} else if (is_badblock(rdev, sh->sector,
		STRIPE_SECTORS,
		&first_bad, &bad_sectors))
		&first_bad, &bad_sectors)) {
		set_bit(R5_MadeGood, &sh->dev[i].flags);
		if (test_bit(R5_ReadError, &sh->dev[i].flags))
		/* That was a successful write so make
		* sure it looks like we already did
		* a re-write.
		*/
		set_bit(R5_ReWrite, &sh->dev[i].flags);
		}
		}
		rdev_dec_pending(rdev, conf->mddev);

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