Re: [PATCH 04/15] btrfs: combine device update operations during transaction commit

[Nikolay Borisov]

On 4.02.19 г. 15:25 ч., Johannes Thumshirn wrote:
> On 30/01/2019 15:50, Nikolay Borisov wrote:
>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index 888d72dda794..25dab68070dc 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -4498,6 +4498,15 @@ void btrfs_cleanup_one_transaction(struct 
>> btrfs_transaction *cur_trans,
>>      ASSERT(list_empty(&cur_trans->dirty_bgs));
>>      ASSERT(list_empty(&cur_trans->io_bgs));
>>  
>> +    while (!list_empty(&cur_trans->dev_update_list)) {
>> +            struct btrfs_device *dev;
>> +
>> +            dev = list_first_entry(&cur_trans->dev_update_list,
>> +                                   struct btrfs_device,
>> +                                   post_commit_list);
>> +            list_del_init(&dev->post_commit_list);
>> +    }
>> +
> 
> Why not?
> 
>       list_for_each_entry_safe(dev, next, &cur_trans->dev_update_list,
>                                post_commit_list)
>               list_del_init(&dev->post_commit_list);

Yep, that should work as well, given that there could be no new updates
in the transaction at the point we are cleaning it up.
>