Re: [PATCH 3/3] bcache: Remove redundant block_size assignment

[wangyijing <wangyijing@huawei.com>]

在 2016/5/11 9:41, Eric Wheeler 写道:
> On Tue, 10 May 2016, Yijing Wang wrote:
> 
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> ---
>>  drivers/md/bcache/super.c |    1 -
>>  1 files changed, 0 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
>> index 1ccb9be..64d0be6 100644
>> --- a/drivers/md/bcache/super.c
>> +++ b/drivers/md/bcache/super.c
>> @@ -134,7 +134,6 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
>>  	case BCACHE_SB_VERSION_CDEV:
>>  	case BCACHE_SB_VERSION_CDEV_WITH_UUID:
>>  		sb->nbuckets	= le64_to_cpu(s->nbuckets);
>> -		sb->block_size	= le16_to_cpu(s->block_size);
>>  		sb->bucket_size	= le16_to_cpu(s->bucket_size);
> 
> 
> Are you sure we want to do that?  
> 
> The bcache superblock allows us to assign the block size presented by 
> bcache and we wouldn't want 4k users to suddenly revert to 512b.  

Hi, I have nothing functional to change here, we have assigned block_size already before here.

	sb->block_size	= le16_to_cpu(s->block_size);    //first assignment

	err = "Superblock block size smaller than device block size";
	if (sb->block_size << 9 < bdev_logical_block_size(bdev))
		goto err;

	switch (sb->version) {
	case BCACHE_SB_VERSION_BDEV:
		sb->data_offset	= BDEV_DATA_START_DEFAULT;
		break;
	case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
		sb->data_offset	= le64_to_cpu(s->data_offset);

		err = "Bad data offset";
		if (sb->data_offset < BDEV_DATA_START_DEFAULT)
			goto err;

		break;
	case BCACHE_SB_VERSION_CDEV:
	case BCACHE_SB_VERSION_CDEV_WITH_UUID:
		sb->nbuckets	= le64_to_cpu(s->nbuckets);
		sb->block_size	= le16_to_cpu(s->block_size);       //redundant one

Thanks!
Yijing.


> 
> 
> --
> Eric Wheeler
> 
> 
> 
>>  
>>  		sb->nr_in_set	= le16_to_cpu(s->nr_in_set);
>> -- 
>> 1.7.1
>>
>> --
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> 
> .
>