[v2] md: bugfix of writing raid sysfs

[PATCH v2 3/4] md/raid10: fix wrong setting of max_corr_read_errors

Posted by linan666@huaweicloud.com 2 years, 9 months ago

From: Li Nan <linan122@huawei.com>

max_corr_read_errors should not be negative number. Change it to
unsigned int where use it.

Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of correctable read errors.")
Signed-off-by: Li Nan <linan122@huawei.com>
---
 drivers/md/md.c     | 2 +-
 drivers/md/raid10.c | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fd5c3babcd6d..4a1e566d6bdc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4486,7 +4486,7 @@ __ATTR_PREALLOC(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_stor
 
 static ssize_t
 max_corrected_read_errors_show(struct mddev *mddev, char *page) {
-	return sprintf(page, "%d\n",
+	return sprintf(page, "%u\n",
 		       atomic_read(&mddev->max_corr_read_errors));
 }
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 4fcfcb350d2b..4d615fcc6a50 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2727,7 +2727,8 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
 	int sect = 0; /* Offset from r10_bio->sector */
 	int sectors = r10_bio->sectors;
 	struct md_rdev *rdev;
-	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
+	unsigned int max_read_errors =
+			atomic_read(&mddev->max_corr_read_errors);
 	int d = r10_bio->devs[r10_bio->read_slot].devnum;
 
 	/* still own a reference to this rdev, so it cannot
@@ -2743,7 +2744,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
 	check_decay_read_errors(mddev, rdev);
 	atomic_inc(&rdev->read_errors);
 	if (atomic_read(&rdev->read_errors) > max_read_errors) {
-		pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
+		pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %u:max %u]\n",
 			  mdname(mddev), rdev->bdev,
 			  atomic_read(&rdev->read_errors), max_read_errors);
 		pr_notice("md/raid10:%s: %pg: Failing raid device\n",
-- 
2.31.1

Re: [PATCH v2 3/4] md/raid10: fix wrong setting of max_corr_read_errors

Posted by Yu Kuai 2 years, 9 months ago

Hi,

在 2023/05/06 9:23, linan666@huaweicloud.com 写道:
> From: Li Nan <linan122@huawei.com>
> 
> max_corr_read_errors should not be negative number. Change it to
> unsigned int where use it.
> 

Looks good, feel free to add:

Reviewed-by: Yu Kuai <yukuai3@huawei.com>

> Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of correctable read errors.")
> Signed-off-by: Li Nan <linan122@huawei.com>
> ---
>   drivers/md/md.c     | 2 +-
>   drivers/md/raid10.c | 5 +++--
>   2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index fd5c3babcd6d..4a1e566d6bdc 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -4486,7 +4486,7 @@ __ATTR_PREALLOC(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_stor
>   
>   static ssize_t
>   max_corrected_read_errors_show(struct mddev *mddev, char *page) {
> -	return sprintf(page, "%d\n",
> +	return sprintf(page, "%u\n",
>   		       atomic_read(&mddev->max_corr_read_errors));
>   }
>   
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 4fcfcb350d2b..4d615fcc6a50 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -2727,7 +2727,8 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
>   	int sect = 0; /* Offset from r10_bio->sector */
>   	int sectors = r10_bio->sectors;
>   	struct md_rdev *rdev;
> -	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
> +	unsigned int max_read_errors =
> +			atomic_read(&mddev->max_corr_read_errors);
>   	int d = r10_bio->devs[r10_bio->read_slot].devnum;
>   
>   	/* still own a reference to this rdev, so it cannot
> @@ -2743,7 +2744,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
>   	check_decay_read_errors(mddev, rdev);
>   	atomic_inc(&rdev->read_errors);
>   	if (atomic_read(&rdev->read_errors) > max_read_errors) {
> -		pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
> +		pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %u:max %u]\n",
>   			  mdname(mddev), rdev->bdev,
>   			  atomic_read(&rdev->read_errors), max_read_errors);
>   		pr_notice("md/raid10:%s: %pg: Failing raid device\n",
>

Re: [PATCH v2 3/4] md/raid10: fix wrong setting of max_corr_read_errors

Posted by Song Liu 2 years, 9 months ago

On Fri, May 5, 2023 at 7:02 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> Hi,
>
> 在 2023/05/06 9:23, linan666@huaweicloud.com 写道:
> > From: Li Nan <linan122@huawei.com>
> >
> > max_corr_read_errors should not be negative number. Change it to
> > unsigned int where use it.
> >
>
> Looks good, feel free to add:
>
> Reviewed-by: Yu Kuai <yukuai3@huawei.com>
>
> > Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of correctable read errors.")
> > Signed-off-by: Li Nan <linan122@huawei.com>

Hmm.. Does the current code break in any cases?

Thanks,
Song

> > ---
> >   drivers/md/md.c     | 2 +-
> >   drivers/md/raid10.c | 5 +++--
> >   2 files changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/md/md.c b/drivers/md/md.c
> > index fd5c3babcd6d..4a1e566d6bdc 100644
> > --- a/drivers/md/md.c
> > +++ b/drivers/md/md.c
> > @@ -4486,7 +4486,7 @@ __ATTR_PREALLOC(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_stor
> >
> >   static ssize_t
> >   max_corrected_read_errors_show(struct mddev *mddev, char *page) {
> > -     return sprintf(page, "%d\n",
> > +     return sprintf(page, "%u\n",
> >                      atomic_read(&mddev->max_corr_read_errors));
> >   }
> >
> > diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> > index 4fcfcb350d2b..4d615fcc6a50 100644
> > --- a/drivers/md/raid10.c
> > +++ b/drivers/md/raid10.c
> > @@ -2727,7 +2727,8 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
> >       int sect = 0; /* Offset from r10_bio->sector */
> >       int sectors = r10_bio->sectors;
> >       struct md_rdev *rdev;
> > -     int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
> > +     unsigned int max_read_errors =
> > +                     atomic_read(&mddev->max_corr_read_errors);
> >       int d = r10_bio->devs[r10_bio->read_slot].devnum;
> >
> >       /* still own a reference to this rdev, so it cannot
> > @@ -2743,7 +2744,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
> >       check_decay_read_errors(mddev, rdev);
> >       atomic_inc(&rdev->read_errors);
> >       if (atomic_read(&rdev->read_errors) > max_read_errors) {
> > -             pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
> > +             pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %u:max %u]\n",
> >                         mdname(mddev), rdev->bdev,
> >                         atomic_read(&rdev->read_errors), max_read_errors);
> >               pr_notice("md/raid10:%s: %pg: Failing raid device\n",
> >
>

Re: [PATCH v2 3/4] md/raid10: fix wrong setting of max_corr_read_errors

Posted by Yu Kuai 2 years, 9 months ago

Hi,

在 2023/05/13 9:08, Song Liu 写道:
> On Fri, May 5, 2023 at 7:02 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>>
>> Hi,
>>
>> 在 2023/05/06 9:23, linan666@huaweicloud.com 写道:
>>> From: Li Nan <linan122@huawei.com>
>>>
>>> max_corr_read_errors should not be negative number. Change it to
>>> unsigned int where use it.
>>>
>>
>> Looks good, feel free to add:
>>
>> Reviewed-by: Yu Kuai <yukuai3@huawei.com>
>>
>>> Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of correctable read errors.")
>>> Signed-off-by: Li Nan <linan122@huawei.com>
> 
> Hmm.. Does the current code break in any cases?

The problem is that somewhere use unsigned value, and somewhere use
signed value, and I thinsk the only functional change is in
fix_read_error(), if max_read_errors is negative, the judgement will
always pass before this patch:

if (atomic_read(&rdev->read_errors) > max_read_errors)

Thanks,
Kuai
> 
> Thanks,
> Song
> 
>>> ---
>>>    drivers/md/md.c     | 2 +-
>>>    drivers/md/raid10.c | 5 +++--
>>>    2 files changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/md/md.c b/drivers/md/md.c
>>> index fd5c3babcd6d..4a1e566d6bdc 100644
>>> --- a/drivers/md/md.c
>>> +++ b/drivers/md/md.c
>>> @@ -4486,7 +4486,7 @@ __ATTR_PREALLOC(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_stor
>>>
>>>    static ssize_t
>>>    max_corrected_read_errors_show(struct mddev *mddev, char *page) {
>>> -     return sprintf(page, "%d\n",
>>> +     return sprintf(page, "%u\n",
>>>                       atomic_read(&mddev->max_corr_read_errors));
>>>    }
>>>
>>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>>> index 4fcfcb350d2b..4d615fcc6a50 100644
>>> --- a/drivers/md/raid10.c
>>> +++ b/drivers/md/raid10.c
>>> @@ -2727,7 +2727,8 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
>>>        int sect = 0; /* Offset from r10_bio->sector */
>>>        int sectors = r10_bio->sectors;
>>>        struct md_rdev *rdev;
>>> -     int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
>>> +     unsigned int max_read_errors =
>>> +                     atomic_read(&mddev->max_corr_read_errors);
>>>        int d = r10_bio->devs[r10_bio->read_slot].devnum;
>>>
>>>        /* still own a reference to this rdev, so it cannot
>>> @@ -2743,7 +2744,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
>>>        check_decay_read_errors(mddev, rdev);
>>>        atomic_inc(&rdev->read_errors);
>>>        if (atomic_read(&rdev->read_errors) > max_read_errors) {
>>> -             pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
>>> +             pr_notice("md/raid10:%s: %pg: Raid device exceeded read_error threshold [cur %u:max %u]\n",
>>>                          mdname(mddev), rdev->bdev,
>>>                          atomic_read(&rdev->read_errors), max_read_errors);
>>>                pr_notice("md/raid10:%s: %pg: Failing raid device\n",
>>>
>>
> .
>

Re: [PATCH v2 3/4] md/raid10: fix wrong setting of max_corr_read_errors

Posted by Li Nan 2 years, 9 months ago


在 2023/5/13 10:21, Yu Kuai 写道:
> Hi,
> 
> 在 2023/05/13 9:08, Song Liu 写道:
>> On Fri, May 5, 2023 at 7:02 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>>>
>>> Hi,
>>>
>>> 在 2023/05/06 9:23, linan666@huaweicloud.com 写道:
>>>> From: Li Nan <linan122@huawei.com>
>>>>
>>>> max_corr_read_errors should not be negative number. Change it to
>>>> unsigned int where use it.
>>>>
>>>
>>> Looks good, feel free to add:
>>>
>>> Reviewed-by: Yu Kuai <yukuai3@huawei.com>
>>>
>>>> Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of 
>>>> correctable read errors.")
>>>> Signed-off-by: Li Nan <linan122@huawei.com>
>>
>> Hmm.. Does the current code break in any cases?
> 
> The problem is that somewhere use unsigned value, and somewhere use
> signed value, and I thinsk the only functional change is in
> fix_read_error(), if max_read_errors is negative, the judgement will
> always pass before this patch:
> 
> if (atomic_read(&rdev->read_errors) > max_read_errors)
> 

In addition, it is confusing for users after setting a huge number to it.
   # echo 4294967295 > /sys/block/$disk/md/max_read_errors
   # cat /sys/block/$disk/md/max_read_errors
     -1

-- 
Thanks,
Nan