Re: [PATCH] btrfs-progs: Cleanup for using BTRFS_SETGET_STACK instead of raw convert

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

于 2013年07月03日 01:36, David Sterba 写道:
> On Wed, Jun 26, 2013 at 01:27:08PM +0800, Qu Wenruo wrote:
>> --- a/btrfs-convert.c
>> +++ b/btrfs-convert.c
>> @@ -1802,7 +1802,7 @@ static int prepare_system_chunk_sb(struct btrfs_super_block *super)
>>   	btrfs_set_stack_chunk_num_stripes(chunk, 1);
>>   	btrfs_set_stack_chunk_sub_stripes(chunk, 0);
>>   	chunk->stripe.devid = super->dev_item.devid;
> This should use the btrfs_set_* accessors too, right?
I'm afraid not. :(

chunk->stripe.devid is __le64 and so the same is dev_item.devid.
btrfs_set_* is calling cpu_to_le64, but neither of them is u64.

If using btrfs_set_*, we need to first convert le64 to cpu and then 
convert back.
So here I didn't use the btrfs_set_* functions.

>
>> -	chunk->stripe.offset = cpu_to_le64(0);
>> +	btrfs_set_stack_stripe_offset(&chunk->stripe, 0);
>>   	memcpy(chunk->stripe.dev_uuid, super->dev_item.uuid, BTRFS_UUID_SIZE);
>>   	btrfs_set_super_sys_array_size(super, sizeof(*key) + sizeof(*chunk));
>>   	return 0;
>> --- a/btrfs-image.c
>> +++ b/btrfs-image.c
>> @@ -1332,7 +1332,7 @@ static void update_super_old(u8 *buffer)
>>   	btrfs_set_stack_chunk_num_stripes(chunk, 1);
>>   	btrfs_set_stack_chunk_sub_stripes(chunk, 0);
>>   	chunk->stripe.devid = super->dev_item.devid;
> same here, and there's one more in update_super().
Same reason above.

>
>> -	chunk->stripe.offset = cpu_to_le64(0);
>> +	btrfs_set_stack_stripe_offset(&chunk->stripe, 0);
>>   	memcpy(chunk->stripe.dev_uuid, super->dev_item.uuid, BTRFS_UUID_SIZE);
>>   	btrfs_set_super_sys_array_size(super, sizeof(*key) + sizeof(*chunk));
>>   	csum_block(buffer, 4096);


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Qu Wenruo
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