Re: [PATCH 1/2] btrfs: use correct offset for reloc_inode in prealloc_file_extent_cluster()

[Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>]

hello,

On 07/07/2016 03:54 AM, Liu Bo wrote:
> On Wed, Jul 06, 2016 at 06:37:52PM +0800, Wang Xiaoguang wrote:
>> In prealloc_file_extent_cluster(), btrfs_check_data_free_space() uses
>> wrong file offset for reloc_inode, it uses cluster->start and cluster->end,
>> which indeed are extent's bytenr. The correct value should be
>> cluster->[start|end] minus block group's start bytenr.
>>
>> start bytenr   cluster->start
>> |              |     extent      |   extent   | ...| extent |
>> |----------------------------------------------------------------|
>> |                block group reloc_inode                         |
>>
>> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
>> ---
>>   fs/btrfs/relocation.c | 27 +++++++++++++++------------
>>   1 file changed, 15 insertions(+), 12 deletions(-)
>>
>> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
>> index 0477dca..abc2f69 100644
>> --- a/fs/btrfs/relocation.c
>> +++ b/fs/btrfs/relocation.c
>> @@ -3030,34 +3030,37 @@ int prealloc_file_extent_cluster(struct inode *inode,
>>   	u64 num_bytes;
>>   	int nr = 0;
>>   	int ret = 0;
>> +	u64 prealloc_start, prealloc_end;
>>   
>>   	BUG_ON(cluster->start != cluster->boundary[0]);
>>   	inode_lock(inode);
>>   
>> -	ret = btrfs_check_data_free_space(inode, cluster->start,
>> -					  cluster->end + 1 - cluster->start);
>> +	start = cluster->start - offset;
>> +	end = cluster->end - offset;
>> +	ret = btrfs_check_data_free_space(inode, start, end + 1 - start);
>>   	if (ret)
>>   		goto out;
>>   
>>   	while (nr < cluster->nr) {
>> -		start = cluster->boundary[nr] - offset;
>> +		prealloc_start = cluster->boundary[nr] - offset;
>>   		if (nr + 1 < cluster->nr)
>> -			end = cluster->boundary[nr + 1] - 1 - offset;
>> +			prealloc_end = cluster->boundary[nr + 1] - 1 - offset;
>>   		else
>> -			end = cluster->end - offset;
>> +			prealloc_end = cluster->end - offset;
>>   
>> -		lock_extent(&BTRFS_I(inode)->io_tree, start, end);
>> -		num_bytes = end + 1 - start;
>> -		ret = btrfs_prealloc_file_range(inode, 0, start,
>> +		lock_extent(&BTRFS_I(inode)->io_tree, prealloc_start,
>> +			    prealloc_end);
>> +		num_bytes = prealloc_end + 1 - prealloc_start;
>> +		ret = btrfs_prealloc_file_range(inode, 0, prealloc_start,
>>   						num_bytes, num_bytes,
>> -						end + 1, &alloc_hint);
>> -		unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
>> +						prealloc_end + 1, &alloc_hint);
>> +		unlock_extent(&BTRFS_I(inode)->io_tree, prealloc_start,
>> +			      prealloc_end);
> Changing names is unnecessary, we can pick up other names for btrfs_{check/free}_data_free_space().
OK, then the changes will be small, thanks.

Regards,
Xiaoguang Wang

>
> Thanks,
>
> -liubo
>
>>   		if (ret)
>>   			break;
>>   		nr++;
>>   	}
>> -	btrfs_free_reserved_data_space(inode, cluster->start,
>> -				       cluster->end + 1 - cluster->start);
>> +	btrfs_free_reserved_data_space(inode, start, end + 1 - start);
>>   out:
>>   	inode_unlock(inode);
>>   	return ret;
>> -- 
>> 2.9.0
>>
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>