On Sun, 1 Sep 2013 20:13:02 -0400 ycbzzjlby@xxxxxxxxx wrote:
> From: Bian Yu <bianyu@xxxxxxxxxxx>
>
> Because of block layer merge, one bio fails will cause other bios
> which belongs to the same request fails, so raid5_end_read_request
> will record all these bios as badblocks.
> If retry request with R5_ReadNoMerge flag to avoid bios merge,
> badblocks can only record sector which is bad exactly.
>
> test:
> hdparm --yes-i-know-what-i-am-doing --make-bad-sector 300000 /dev/sdb
> mdadm -C /dev/md0 -l5 -n3 /dev/sd[bcd] --assume-clean
> mdadm /dev/md0 -f /dev/sdd
> mdadm /dev/md0 -r /dev/sdd
> mdadm --zero-superblock /dev/sdd
> mdadm /dev/md0 -a /dev/sdd
>
> 1. Without this patch:
> cat /sys/block/md0/md/rd*/bad_blocks
> 299776 256
> 299776 256
>
> 2. With this patch:
> cat /sys/block/md0/md/rd*/bad_blocks
> 300000 8
> 300000 8
>
> Signed-off-by: Bian Yu <bianyu@xxxxxxxxxxx>
> ---
> drivers/md/raid5.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index ff1aecf..ee8c280 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -1924,6 +1924,9 @@ static void raid5_end_read_request(struct bio * bi, int error)
> mdname(conf->mddev), bdn);
> else
> retry = 1;
> + if (set_bad && test_bit(In_sync, &rdev->flags)
> + && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
> + retry = 1;
> if (retry)
> if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
> set_bit(R5_ReadError, &sh->dev[i].flags);
Applied, thanks.
NeilBrown
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