Hello,
2013/2/22 Arne Jansen <sensi...@gmx.net>:
> On 02/22/13 13:09, Wang Shilong wrote:
>> From: Wang Shilong <wangsl-f...@cn.fujitsu.com>
>>
>> This patch tries to stop users to create/destroy qgroup level 0,
>> users can only create/destroy qgroup level more than 0.
>>
>> See the fact:
>> a subvolume/snapshot qgroup was created automatically
>> when creating subvolume/snapshot, so creating a qgroup level 0 can't
>> be a subvolume/snapshot qgroup, the only way to use it is that assigning
>> subvolume/snapshot qgroup to it, the point is that we don't want to have a
>> parent qgroup whose level is 0.
>>
>> So we want to force users to use qgroup with clear relations
>> which means a parent qgroup's level > child qgroup's level.For example:
>>
>> 2/0
>> / \
>> / \
>> / \
>> 1/0 1/1
>> / \ \
>> / \ \
>> / \ \
>> 0/256 0/257 0/258
>>
>> This pattern of quota is nature and easy for users to understand, otherwise
>> it will
>> make the quota configuration confusing and difficult to maintain.
>
> I agree that a strict hierarchy of the levels should be enforced.
> Currently the kernel has no idea of 'level', it's just an artificial
> concept that lives in userspace. This patch would be the first place
> to add that magic shift '48' to the kernel.
> In my opinion it would be sufficient to do the enforcement in user
> space, as it is of no technical nature.
>
...i have made some patches about these work in btrfs-prog, but it has
been not merged...
I will pick up thoses patches and do the other necessary work..
Thanks,
Wang
> -Arne
>
>>
>> Signed-off-by: Wang Shilong <wangsl-f...@cn.fujitsu.com>
>> Acked-by: Miao Xie <mi...@cn.fujitsu.com>
>> Cc: Arne Jansen <sensi...@gmx.net>
>> ---
>> fs/btrfs/ioctl.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index a31cd93..3590c21 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -3755,7 +3755,7 @@ static long btrfs_ioctl_qgroup_create(struct file
>> *file, void __user *arg)
>> goto drop_write;
>> }
>>
>> - if (!sa->qgroupid) {
>> + if (!(sa->qgroupid >> 48)) {
>> ret = -EINVAL;
>> goto out;
>> }
>>
>
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