On 02/19/2013 09:55 AM, Dave Chinner wrote:
> On Sun, Feb 17, 2013 at 05:10:58PM -0800, Eric W. Biederman wrote:
>> From: "Eric W. Biederman" <ebied...@xmission.com>
>>
>> - Convert the userspace value in fa->fsx_projid into a kprojid and
>>   store it in the variable projid.
>> - Verify that xfs can store the projid after it is converted into
>>   xfs's user namespace.
>> - Replace uses of fa->fsx_projid with projid throughout
>>   xfs_ioctl_setattr.
>>
>> Cc: Ben Myers <b...@sgi.com>
>> Cc: Alex Elder <el...@kernel.org>
>> Cc: Dave Chinner <da...@fromorbit.com>
>> Signed-off-by: "Eric W. Biederman" <ebied...@xmission.com>
>> ---
>>  fs/xfs/xfs_ioctl.c |   26 ++++++++++++++++++--------
>>  1 files changed, 18 insertions(+), 8 deletions(-)
>>
>> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
>> index 016624b..4a55f50 100644
>> --- a/fs/xfs/xfs_ioctl.c
>> +++ b/fs/xfs/xfs_ioctl.c
>> @@ -925,6 +925,7 @@ xfs_ioctl_setattr(
>>      struct xfs_dquot        *gdqp = NULL;
>>      struct xfs_dquot        *olddquot = NULL;
>>      int                     code;
>> +    kprojid_t               projid = INVALID_PROJID;
>>  
>>      trace_xfs_ioctl_setattr(ip);
>>  
>> @@ -934,11 +935,20 @@ xfs_ioctl_setattr(
>>              return XFS_ERROR(EIO);
>>  
>>      /*
>> -     * Disallow 32bit project ids when projid32bit feature is not enabled.
>> +     * Verify the specifid project id is valid.
>>       */
>> -    if ((mask & FSX_PROJID) && (fa->fsx_projid > (__uint16_t)-1) &&
>> -                    !xfs_sb_version_hasprojid32bit(&ip->i_mount->m_sb))
>> -            return XFS_ERROR(EINVAL);
>> +    if (mask & FSX_PROJID) {
>> +            projid = make_kprojid(current_user_ns(), fa->fsx_projid);
>> +            if (!projid_valid(projid))
>> +                    return XFS_ERROR(EINVAL);
>> +
>> +            /*
>> +             * Disallow 32bit project ids when projid32bit feature is not 
>> enabled.
>> +             */
>> +            if ((from_kprojid(&init_user_ns, projid) > (__uint16_t)-1) &&
>> +                !xfs_sb_version_hasprojid32bit(&ip->i_mount->m_sb))
>> +                    return XFS_ERROR(EINVAL);
>> +    }
> 
> That looks busted. Why does one use current_user_ns() and the other
> &init_user_ns()?
> 

hmm, through this thread had been stopped discussing for a long time, but I'm 
working on converting
ids to kids for xfs now, and I want to remove the finial dependenciy for user 
namespace.

Maybe I can explain why.

projid = make_kprojid(current_user_ns(), fa->fsx_projid);

this code translates the projid in current user namespace to the global kernel 
projid(kprojid_t).

and from_kprojid(&init_user_ns, projid) here is equal to projid.val, since the 
real value
of global kernel projid and projid is same in init user namespace.

After translating projid to global kernel projid, we should check if the real 
value of this
global kernel projid is valid.

I think maybe just modifying from_kprojid(&init_user_ns, projid) to projid.val 
here is easier
to understand.


Thanks!
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