Re: Re: [PATCH] md/raid1:combine code in fix_read_error andfix_sync_read_error.

["majianpeng" <majianpeng@gmail.com>]

Thanks,Neil.I did not  notice the data buff is the same when write and read.

------------------				 
majianpeng
2012-04-10

-------------------------------------------------------------
发件人：NeilBrown
发送日期：2012-04-10 07:47:15
收件人：majianpeng
抄送：linux-raid
主题：Re: [PATCH] md/raid1:combine code in fix_read_error andfix_sync_read_error.

On Fri, 6 Apr 2012 15:15:38 +0800 "majianpeng" <majianpeng@gmail.com> wrote:

> >From d8d5044e65ed2bea15e135918699777c49b6f224 Mon Sep 17 00:00:00 2001
> From: majianpeng <majianpeng@gmail.com>
> Date: Fri, 6 Apr 2012 15:07:33 +0800
> Subject: [PATCH] md/raid1:combine code in fix_read_error and
>  fix_sync_read_error.
>


your explanation for the patch is, again, too short.

I don't agree with this patch, I'd rather leave it as it is.

I want to perform all the writes before any reads.

If a read fails, I cannot be certain what the contents of the buffer are, so
I don't want to risk writing it anywhere.

Thanks,
NeilBrown


> 
> Signed-off-by: majianpeng <majianpeng@gmail.com>
> ---
>  drivers/md/raid1.c |   36 ++++++++----------------------------
>  1 files changed, 8 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index d35e4c9..a9a4361 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -1603,7 +1603,6 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
>  		int d = r1_bio->read_disk;
>  		int success = 0;
>  		struct md_rdev *rdev;
> -		int start;
>  
>  		if (s > (PAGE_SIZE>>9))
>  			s = PAGE_SIZE >> 9;
> @@ -1661,7 +1660,6 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
>  			continue;
>  		}
>  
> -		start = d;
>  		/* write it back and re-read */
>  		while (d != r1_bio->read_disk) {
>  			if (d == 0)
> @@ -1675,21 +1673,12 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
>  					    WRITE) == 0) {
>  				r1_bio->bios[d]->bi_end_io = NULL;
>  				rdev_dec_pending(rdev, mddev);
> -			}
> -		}
> -		d = start;
> -		while (d != r1_bio->read_disk) {
> -			if (d == 0)
> -				d = conf->raid_disks * 2;
> -			d--;
> -			if (r1_bio->bios[d]->bi_end_io != end_sync_read)
> -				continue;
> -			rdev = conf->mirrors[d].rdev;
> -			if (r1_sync_page_io(rdev, sect, s,
> -					    bio->bi_io_vec[idx].bv_page,
> -					    READ) != 0)
> +			} else if (r1_sync_page_io(rdev, sect, s,
> +					    bio->bi_io_vec[idx].bv_page, READ))
>  				atomic_add(s, &rdev->corrected_errors);
> +
>  		}
> +
>  		sectors -= s;
>  		sect += s;
>  		idx ++;
> @@ -1841,7 +1830,6 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
>  		int s = sectors;
>  		int d = read_disk;
>  		int success = 0;
> -		int start;
>  		struct md_rdev *rdev;
>  
>  		if (s > (PAGE_SIZE>>9))
> @@ -1878,19 +1866,8 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
>  				md_error(mddev, rdev);
>  			break;
>  		}
> +
>  		/* write it back and re-read */
> -		start = d;
> -		while (d != read_disk) {
> -			if (d==0)
> -				d = conf->raid_disks * 2;
> -			d--;
> -			rdev = conf->mirrors[d].rdev;
> -			if (rdev &&
> -			    test_bit(In_sync, &rdev->flags))
> -				r1_sync_page_io(rdev, sect, s,
> -						conf->tmppage, WRITE);
> -		}
> -		d = start;
>  		while (d != read_disk) {
>  			char b[BDEVNAME_SIZE];
>  			if (d==0)
> @@ -1900,6 +1877,9 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
>  			if (rdev &&
>  			    test_bit(In_sync, &rdev->flags)) {
>  				if (r1_sync_page_io(rdev, sect, s,
> +						conf->tmppage, WRITE) == 0)
> +					continue;
> +				else if (r1_sync_page_io(rdev, sect, s,
>  						    conf->tmppage, READ)) {
>  					atomic_add(s, &rdev->corrected_errors);
>  					printk(KERN_INFO