Re: Re: md/raid1:Fix a logic bug in fix_sync_read_error().

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

>>That is correct, and that is how it should be.

>>If we get a read error, then try again and get a successful read, then there
>>is nothing more that we need to do.  No need to write or anything.

>>So: current code is correct.

>>Thanks,
>>NeilBrown
Sorry Neil,I don't understand what's your mean?
I think this function is want to do something like follow when all sync_read failed.
1:want to read partly by PAGE_SIZE from all read devices.
2:if read success and write write to other and read back, in order to repair those disks.

for example :
disk A,B ,read 64k from 0 to 128 sector.
supposed: disk A read failed because sector 0-7 was bad sector.
			   disk B  read failed because sector 8-15 was bad sector.
by this function,we can fix sector 0-7 of A and sector 8-15 of B.
Is ok?

If B is read_disk,so read 0-7 is ok and want to write it to A.But becasue the code ,do not write to disk A.

------------------				 
kedacomkernel
2012-04-05

-------------------------------------------------------------
发件人：NeilBrown
发送日期：2012-04-02 10:05:34
收件人：kedacomkernel
抄送：linux-raid
主题：Re: md/raid1:Fix a logic bug in fix_sync_read_error().

On Sat, 31 Mar 2012 10:38:01 +0800 "kedacomkernel" <kedacomkernel@gmail.com>
wrote:

> >From 0fe15c8e1bd5e46234d37573f3322312d8da325d Mon Sep 17 00:00:00 2001
> From: majianpeng <majianpeng@gmail.com>
> Date: Sat, 31 Mar 2012 10:27:33 +0800
> Subject: [PATCH] md/raid1:Fix a logic bug in fix_sync_read_error(). 
> If  d==read_disk && success == 1 and then break, so d =
>  read_disk. When exec this judgement: >>start = d; >>/*
>  write it back and re-read */ >>while (d !=
>  r1_bio->read_disk) { Because d == read_disk,so write and
>  re-add did not exec.

That is correct, and that is how it should be.

If we get a read error, then try again and get a successful read, then there
is nothing more that we need to do.  No need to write or anything.

So: current code is correct.

Thanks,
NeilBrown


> 
> 
> Signed-off-by: majianpeng <majianpeng@gmail.com>
> ---
>  drivers/md/raid1.c |    1 -
>  1 files changed, 0 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 4a40a20..3a133ff 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -1618,7 +1618,6 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
>  						 bio->bi_io_vec[idx].bv_page,
>  						 READ, false)) {
>  					success = 1;
> -					break;
>  				}
>  			}
>  			d++;