[PATCH 1/2] bcache: Remove redundant set_capacity

[PATCH 1/2] bcache: Remove redundant set_capacity

[Yijing Wang]

set_capacity() has been called in bcache_device_init(),
remove the redundant one.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
 drivers/md/bcache/super.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 849ad44..b638a16 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1126,9 +1126,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
 	if (ret)
 		return ret;
 
-	set_capacity(dc->disk.disk,
-		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
-
 	dc->disk.disk->queue->backing_dev_info.ra_pages =
 		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
 		    q->backing_dev_info.ra_pages);
-- 
2.5.0

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[Coly Li]

On 2016/11/25 上午9:39, Yijing Wang wrote:
> set_capacity() has been called in bcache_device_init(),
> remove the redundant one.
> 
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> ---
>  drivers/md/bcache/super.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 849ad44..b638a16 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1126,9 +1126,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
>  	if (ret)
>  		return ret;
>  
> -	set_capacity(dc->disk.disk,
> -		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
> -
>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
>  		    q->backing_dev_info.ra_pages);
> 

Hi Yijing,

Nice catch, it looks good to me.

Acked-by: Coly Li <colyli@suse.de>

-- 
Coly Li

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[wangyijing]

在 2016/11/27 15:57, Coly Li 写道:
> On 2016/11/25 上午9:39, Yijing Wang wrote:
>> set_capacity() has been called in bcache_device_init(),
>> remove the redundant one.
>>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> ---
>>  drivers/md/bcache/super.c | 3 ---
>>  1 file changed, 3 deletions(-)
>>
>> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
>> index 849ad44..b638a16 100644
>> --- a/drivers/md/bcache/super.c
>> +++ b/drivers/md/bcache/super.c
>> @@ -1126,9 +1126,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
>>  	if (ret)
>>  		return ret;
>>  
>> -	set_capacity(dc->disk.disk,
>> -		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
>> -
>>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
>>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
>>  		    q->backing_dev_info.ra_pages);
>>
> 
> Hi Yijing,
> 
> Nice catch, it looks good to me.
> 
> Acked-by: Coly Li <colyli@suse.de>

Thanks!

> 

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[Eric Wheeler]

On Fri, 25 Nov 2016, Yijing Wang wrote:

> set_capacity() has been called in bcache_device_init(),
> remove the redundant one.
> 
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> ---
>  drivers/md/bcache/super.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 849ad44..b638a16 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1126,9 +1126,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
>  	if (ret)
>  		return ret;
>  
> -	set_capacity(dc->disk.disk,
> -		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
> -

It probably is a duplicate set_capacity, but has anyone tested bringing on 
a writeback volume, and late-attaching the cache volume with this patch 
applied?

Otherwise stated, is it possible to get the backing device attached 
without setting the capacity?

-Eric

>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
>  		    q->backing_dev_info.ra_pages);
> -- 
> 2.5.0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[wangyijing]

在 2016/11/30 4:49, Eric Wheeler 写道:
> On Fri, 25 Nov 2016, Yijing Wang wrote:
> 
>> set_capacity() has been called in bcache_device_init(),
>> remove the redundant one.
>>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> ---
>>  drivers/md/bcache/super.c | 3 ---
>>  1 file changed, 3 deletions(-)
>>
>> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
>> index 849ad44..b638a16 100644
>> --- a/drivers/md/bcache/super.c
>> +++ b/drivers/md/bcache/super.c
>> @@ -1126,9 +1126,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
>>  	if (ret)
>>  		return ret;
>>  
>> -	set_capacity(dc->disk.disk,
>> -		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
>> -
> 
> It probably is a duplicate set_capacity, but has anyone tested bringing on 
> a writeback volume, and late-attaching the cache volume with this patch 
> applied?
> 
> Otherwise stated, is it possible to get the backing device attached 
> without setting the capacity?

Hi Eric, I tested this case in following steps, the result is fine, the capability is setted.

[root@38 sys]# make-bcache -B /dev/nvme1n1
UUID:			6758bd42-c226-4de9-a6d5-fb003af63f9f
Set UUID:		2661eadd-79b4-4c56-a2fb-9f8b505aa9fd
version:		1
block_size:		1
data_offset:		16
[root@38 sys]# ls /dev/bcache
bcache/  bcache0
[root@38 sys]# fdisk -l
Disk /dev/nvme1n1: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
....
Disk /dev/bcache0: 1.8 TiB, 2000398925824 bytes, 3907029152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
....
[root@38 sys]# make-bcache -C /dev/ram0
UUID:			b64a4425-b9c1-4650-9cab-3856410c9566
Set UUID:		a0a31965-a89d-43b6-a5d6-968897abeb7a
version:		0
nbuckets:		1024
block_size:		1
bucket_size:		1024
nr_in_set:		1
nr_this_dev:		0
first_bucket:		1
[root@38 sys]# echo a0a31965-a89d-43b6-a5d6-968897abeb7a > /sys/block/bcache0/bcache/attach
[root@38 sys]# echo writeback > /sys/block/bcache0/bcache/cache_mode
[root@38 sys]# mount /dev/bcache0 /tmp
[root@38 sys]# cd /tmp/
[root@38 tmp]# fio ~/fio_write.sh
file1: (g=0): rw=randwrite, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
fio-2.2.8
Starting 1 thread
file1: Laying out IO file(s) (1 file(s) / 128MB)
Jobs: 1 (f=1): [w(1)] [0.0% done] [0KB/177.2MB/0KB /s] [0/45.4K/0 iops] [eta 05h:33m:13s]

Thanks!
Yijing.

> 
> -Eric
> 
>>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
>>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
>>  		    q->backing_dev_info.ra_pages);
>> -- 
>> 2.5.0
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> 
> .
> 

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[Eric Wheeler]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 3798 bytes --]

On Wed, 30 Nov 2016, wangyijing wrote:

> 
> 
> 在 2016/11/30 4:49, Eric Wheeler 写道:
> > On Fri, 25 Nov 2016, Yijing Wang wrote:
> > 
> >> set_capacity() has been called in bcache_device_init(),
> >> remove the redundant one.
> >>
> >> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> >> ---
> >>  drivers/md/bcache/super.c | 3 ---
> >>  1 file changed, 3 deletions(-)
> >>
> >> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> >> index 849ad44..b638a16 100644
> >> --- a/drivers/md/bcache/super.c
> >> +++ b/drivers/md/bcache/super.c
> >> @@ -1126,9 +1126,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
> >>  	if (ret)
> >>  		return ret;
> >>  
> >> -	set_capacity(dc->disk.disk,
> >> -		     dc->bdev->bd_part->nr_sects - dc->sb.data_offset);
> >> -
> > 
> > It probably is a duplicate set_capacity, but has anyone tested bringing on 
> > a writeback volume, and late-attaching the cache volume with this patch 
> > applied?
> > 
> > Otherwise stated, is it possible to get the backing device attached 
> > without setting the capacity?
> 
> Hi Eric, I tested this case in following steps, the result is fine, the capability is setted.
> 
> [root@38 sys]# make-bcache -B /dev/nvme1n1
> UUID:			6758bd42-c226-4de9-a6d5-fb003af63f9f
> Set UUID:		2661eadd-79b4-4c56-a2fb-9f8b505aa9fd
> version:		1
> block_size:		1
> data_offset:		16
> [root@38 sys]# ls /dev/bcache
> bcache/  bcache0
> [root@38 sys]# fdisk -l
> Disk /dev/nvme1n1: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
> Units: sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> ....
> Disk /dev/bcache0: 1.8 TiB, 2000398925824 bytes, 3907029152 sectors
> Units: sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> ....
> [root@38 sys]# make-bcache -C /dev/ram0
> UUID:			b64a4425-b9c1-4650-9cab-3856410c9566
> Set UUID:		a0a31965-a89d-43b6-a5d6-968897abeb7a
> version:		0
> nbuckets:		1024
> block_size:		1
> bucket_size:		1024
> nr_in_set:		1
> nr_this_dev:		0
> first_bucket:		1
> [root@38 sys]# echo a0a31965-a89d-43b6-a5d6-968897abeb7a > /sys/block/bcache0/bcache/attach
> [root@38 sys]# echo writeback > /sys/block/bcache0/bcache/cache_mode
> [root@38 sys]# mount /dev/bcache0 /tmp
> [root@38 sys]# cd /tmp/
> [root@38 tmp]# fio ~/fio_write.sh
> file1: (g=0): rw=randwrite, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
> fio-2.2.8
> Starting 1 thread
> file1: Laying out IO file(s) (1 file(s) / 128MB)
> Jobs: 1 (f=1): [w(1)] [0.0% done] [0KB/177.2MB/0KB /s] [0/45.4K/0 iops] [eta 05h:33m:13s]
> 
> Thanks!
> Yijing.

I want to make sure that the set_capacity call that happens on cache 
attachment is not necessary when a backing device is attached without 
its dirty writeback cache since bcache0 is not presented until the cache 
attaches in that case.

Can you also unregister the volume, attach the backing device first, and 
then the cache while the cache is dirty to make sure that the size is set 
correctly?

--
Eric Wheeler

> 
> > 
> > -Eric
> > 
> >>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
> >>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
> >>  		    q->backing_dev_info.ra_pages);
> >> -- 
> >> 2.5.0
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>
> > 
> > .
> > 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[wangyijing]

>>> It probably is a duplicate set_capacity, but has anyone tested bringing on 
>>> a writeback volume, and late-attaching the cache volume with this patch 
>>> applied?
>>>
>>> Otherwise stated, is it possible to get the backing device attached 
>>> without setting the capacity?
>>
>> Hi Eric, I tested this case in following steps, the result is fine, the capability is setted.
>>
>> [root@38 sys]# make-bcache -B /dev/nvme1n1
>> UUID:			6758bd42-c226-4de9-a6d5-fb003af63f9f
>> Set UUID:		2661eadd-79b4-4c56-a2fb-9f8b505aa9fd
>> version:		1
>> block_size:		1
>> data_offset:		16
>> [root@38 sys]# ls /dev/bcache
>> bcache/  bcache0
>> [root@38 sys]# fdisk -l
>> Disk /dev/nvme1n1: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
>> Units: sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>> ....
>> Disk /dev/bcache0: 1.8 TiB, 2000398925824 bytes, 3907029152 sectors
>> Units: sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>> ....
>> [root@38 sys]# make-bcache -C /dev/ram0
>> UUID:			b64a4425-b9c1-4650-9cab-3856410c9566
>> Set UUID:		a0a31965-a89d-43b6-a5d6-968897abeb7a
>> version:		0
>> nbuckets:		1024
>> block_size:		1
>> bucket_size:		1024
>> nr_in_set:		1
>> nr_this_dev:		0
>> first_bucket:		1
>> [root@38 sys]# echo a0a31965-a89d-43b6-a5d6-968897abeb7a > /sys/block/bcache0/bcache/attach
>> [root@38 sys]# echo writeback > /sys/block/bcache0/bcache/cache_mode
>> [root@38 sys]# mount /dev/bcache0 /tmp
>> [root@38 sys]# cd /tmp/
>> [root@38 tmp]# fio ~/fio_write.sh
>> file1: (g=0): rw=randwrite, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
>> fio-2.2.8
>> Starting 1 thread
>> file1: Laying out IO file(s) (1 file(s) / 128MB)
>> Jobs: 1 (f=1): [w(1)] [0.0% done] [0KB/177.2MB/0KB /s] [0/45.4K/0 iops] [eta 05h:33m:13s]
>>
>> Thanks!
>> Yijing.
> 
> I want to make sure that the set_capacity call that happens on cache 
> attachment is not necessary when a backing device is attached without

Hi Eric, set_capacity() which removed in this patch is happened at cached_dev_init()
which is called when register a backing device, what do you mean "set_capacity call that happens on cache
> attachment" ?


> its dirty writeback cache since bcache0 is not presented until the cache 
> attaches in that case.

I found bcache0 device present once we do make-bcache -B /dev/nvme1n1. before attach the cache set.
So I missed something ?

> 
> Can you also unregister the volume, attach the backing device first, and 
> then the cache while the cache is dirty to make sure that the size is set 
> correctly?

When I unregister the cache device, I found all the dirty data has been flushed to
backing device, so how can I do the test the case as you point ?

Thanks!
Yijing.

> 
> --
> Eric Wheeler
> 
>>
>>>
>>> -Eric
>>>
>>>>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
>>>>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
>>>>  		    q->backing_dev_info.ra_pages);
>>>> -- 
>>>> 2.5.0
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>>> .
>>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[Eric Wheeler]

On Thu, 1 Dec 2016, wangyijing wrote:

> 
> >>> It probably is a duplicate set_capacity, but has anyone tested bringing on 
> >>> a writeback volume, and late-attaching the cache volume with this patch 
> >>> applied?
> >>>
> >>> Otherwise stated, is it possible to get the backing device attached 
> >>> without setting the capacity?
> >>
> >> Hi Eric, I tested this case in following steps, the result is fine, the capability is setted.
> >>
> >> [root@38 sys]# make-bcache -B /dev/nvme1n1
> >> UUID:			6758bd42-c226-4de9-a6d5-fb003af63f9f
> >> Set UUID:		2661eadd-79b4-4c56-a2fb-9f8b505aa9fd
> >> version:		1
> >> block_size:		1
> >> data_offset:		16
> >> [root@38 sys]# ls /dev/bcache
> >> bcache/  bcache0
> >> [root@38 sys]# fdisk -l
> >> Disk /dev/nvme1n1: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
> >> Units: sectors of 1 * 512 = 512 bytes
> >> Sector size (logical/physical): 512 bytes / 512 bytes
> >> I/O size (minimum/optimal): 512 bytes / 512 bytes
> >> ....
> >> Disk /dev/bcache0: 1.8 TiB, 2000398925824 bytes, 3907029152 sectors
> >> Units: sectors of 1 * 512 = 512 bytes
> >> Sector size (logical/physical): 512 bytes / 512 bytes
> >> I/O size (minimum/optimal): 512 bytes / 512 bytes
> >> ....
> >> [root@38 sys]# make-bcache -C /dev/ram0
> >> UUID:			b64a4425-b9c1-4650-9cab-3856410c9566
> >> Set UUID:		a0a31965-a89d-43b6-a5d6-968897abeb7a
> >> version:		0
> >> nbuckets:		1024
> >> block_size:		1
> >> bucket_size:		1024
> >> nr_in_set:		1
> >> nr_this_dev:		0
> >> first_bucket:		1
> >> [root@38 sys]# echo a0a31965-a89d-43b6-a5d6-968897abeb7a > /sys/block/bcache0/bcache/attach
> >> [root@38 sys]# echo writeback > /sys/block/bcache0/bcache/cache_mode
> >> [root@38 sys]# mount /dev/bcache0 /tmp
> >> [root@38 sys]# cd /tmp/
> >> [root@38 tmp]# fio ~/fio_write.sh
> >> file1: (g=0): rw=randwrite, bs=4K-4K/4K-4K/4K-4K, ioengine=psync, iodepth=1
> >> fio-2.2.8
> >> Starting 1 thread
> >> file1: Laying out IO file(s) (1 file(s) / 128MB)
> >> Jobs: 1 (f=1): [w(1)] [0.0% done] [0KB/177.2MB/0KB /s] [0/45.4K/0 iops] [eta 05h:33m:13s]
> >>
> >> Thanks!
> >> Yijing.
> > 
> > I want to make sure that the set_capacity call that happens on cache 
> > attachment is not necessary when a backing device is attached without
> 
> Hi Eric, set_capacity() which removed in this patch is happened at cached_dev_init()
> which is called when register a backing device, what do you mean "set_capacity call that happens on cache
> > attachment" ?


I'm sorry, you are correct.  I though this was the cache-dev attachment, 
not the cached-dev attachment.  Looks good.

Reviewed-by: Eric Wheeler <bcache@linux.ewheeler.net>

--
Eric Wheeler

> 
> 
> > its dirty writeback cache since bcache0 is not presented until the cache 
> > attaches in that case.
> 
> I found bcache0 device present once we do make-bcache -B /dev/nvme1n1. before attach the cache set.
> So I missed something ?
> 
> > 
> > Can you also unregister the volume, attach the backing device first, and 
> > then the cache while the cache is dirty to make sure that the size is set 
> > correctly?
> 
> When I unregister the cache device, I found all the dirty data has been flushed to
> backing device, so how can I do the test the case as you point ?
> 
> Thanks!
> Yijing.
> 
> > 
> > --
> > Eric Wheeler
> > 
> >>
> >>>
> >>> -Eric
> >>>
> >>>>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
> >>>>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
> >>>>  		    q->backing_dev_info.ra_pages);
> >>>> -- 
> >>>> 2.5.0
> >>>>
> >>>> --
> >>>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> >>>> the body of a message to majordomo@vger.kernel.org
> >>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>>>
> >>>
> >>> .
> >>>
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 

Re: [PATCH 1/2] bcache: Remove redundant set_capacity

[wangyijing]

>>> I want to make sure that the set_capacity call that happens on cache 
>>> attachment is not necessary when a backing device is attached without
>>
>> Hi Eric, set_capacity() which removed in this patch is happened at cached_dev_init()
>> which is called when register a backing device, what do you mean "set_capacity call that happens on cache
>>> attachment" ?
> 
> 
> I'm sorry, you are correct.  I though this was the cache-dev attachment, 
> not the cached-dev attachment.  Looks good.
> 
> Reviewed-by: Eric Wheeler <bcache@linux.ewheeler.net>
> 

Thanks！

> --
> Eric Wheeler
> 
>>
>>
>>> its dirty writeback cache since bcache0 is not presented until the cache 
>>> attaches in that case.
>>
>> I found bcache0 device present once we do make-bcache -B /dev/nvme1n1. before attach the cache set.
>> So I missed something ?
>>
>>>
>>> Can you also unregister the volume, attach the backing device first, and 
>>> then the cache while the cache is dirty to make sure that the size is set 
>>> correctly?
>>
>> When I unregister the cache device, I found all the dirty data has been flushed to
>> backing device, so how can I do the test the case as you point ?
>>
>> Thanks!
>> Yijing.
>>
>>>
>>> --
>>> Eric Wheeler
>>>
>>>>
>>>>>
>>>>> -Eric
>>>>>
>>>>>>  	dc->disk.disk->queue->backing_dev_info.ra_pages =
>>>>>>  		max(dc->disk.disk->queue->backing_dev_info.ra_pages,
>>>>>>  		    q->backing_dev_info.ra_pages);
>>>>>> -- 
>>>>>> 2.5.0
>>>>>>
>>>>>> --
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>>>>>>
>>>>>
>>>>> .
>>>>>
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
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>>
>>
> 
> .
>