On 08/09/2013 05:42 PM, Arne Jansen wrote:
> On 07.08.2013 07:12, Wang Shilong wrote:
>> btrfs_free_qgroup_config() is not only called by open/close_ctree(),but
>> also btrfs_disable_quota().And for btrfs_disable_quota(),we have set
>> 'quota_root' to be null before calling btrfs_free_qgroup_config(),so it
>> is safe to cleanup in-memory structures without lock held.
>
> Why do you do this? Did the spinlock gave you any trouble?
Because other places such as btrfs_qgroup_reserve() will try spin_lock.
and we should relase spin_lock as soon as possible, luckily we are safe
to move btrfs_free_qgroup_config() out of spin_lock.
>
>>
>> Signed-off-by: Wang Shilong <wangsl.fnst@xxxxxxxxxxxxxx>
>> Reviewed-by: Miao Xie <miaox@xxxxxxxxxxxxxx>
>> ---
>> fs/btrfs/qgroup.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
>> index 3b103e2..b809616 100644
>> --- a/fs/btrfs/qgroup.c
>> +++ b/fs/btrfs/qgroup.c
>> @@ -432,8 +432,10 @@ out:
>> }
>>
>> /*
>> - * This is only called from close_ctree() or open_ctree(), both in single-
>> - * treaded paths. Clean up the in-memory structures. No locking needed.
>> + * This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
>> + * first two are in single-treaded paths.And for the third one, we have set
>
> You could use the opportunity and correct the typo in 'single-treaded'. Also,
> there's a space missing after the period.
I will fix typo.
Thank,
Wang
>
> -Arne
>
>> + * quota_root to be null with qgroup_lock held before, so it is safe to clean
>> + * up the in-memory structures without qgroup_lock held.
>> */
>> void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
>> {
>> @@ -937,9 +939,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
>> fs_info->pending_quota_state = 0;
>> quota_root = fs_info->quota_root;
>> fs_info->quota_root = NULL;
>> - btrfs_free_qgroup_config(fs_info);
>> spin_unlock(&fs_info->qgroup_lock);
>>
>> + btrfs_free_qgroup_config(fs_info);
>> +
>> if (!quota_root) {
>> ret = -EINVAL;
>> goto out;
>
>
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