linux-ext4 - Re: [PATCH v3 1/3] ext4: fix setattr project check upon fssetxattr ioctl

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Date:   Mon, 17 Sep 2018 05:18:13 +0000
From:   Wang Shilong <wshilong@....com>
To:     Theodore Ts'o <tytso@....edu>
CC:     Wang Shilong <wangshilong1991@...il.com>,
        "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
        "linux-f2fs-devel@...ts.sourceforge.net" 
        <linux-f2fs-devel@...ts.sourceforge.net>,
        "dchinner@...hat.com" <dchinner@...hat.com>,
        "adilger@...ger.ca" <adilger@...ger.ca>
Subject: Re: [PATCH v3 1/3] ext4: fix setattr project check upon fssetxattr
 ioctl


> 在 2018年9月16日，下午8:25，Wang Shilong <wshilong@....com> 写道：
> 
> 
> 
>> 在 2018年9月16日，下午8:20，Theodore Y. Ts'o <tytso@....edu> 写道：
>> 
>> On Sun, Sep 16, 2018 at 04:02:52AM +0000, Wang Shilong wrote:
>>> 
>>> 
>>>> 在 2018年9月16日，上午11:55，Theodore Y. Ts'o <tytso@....edu> 写道：
>>>> 
>>>> On Wed, Sep 12, 2018 at 08:57:16AM +0900, Wang Shilong wrote:
>>>>> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
>>>>> index a7074115d6f6..f81102bd3203 100644
>>>>> --- a/fs/ext4/ioctl.c
>>>>> +++ b/fs/ext4/ioctl.c
>>>>> @@ -339,19 +339,14 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
>>>>> 	if (projid_eq(kprojid, EXT4_I(inode)->i_projid))
>>>>> 		return 0;
>>>>> 
>>>>> -	err = mnt_want_write_file(filp);
>>>>> -	if (err)
>>>>> -		return err;
>>>>> -
>>>> 
>>>> A huge part of this patch is dropping the calls to
>>>> mnt_want_write_file() and mnt_drop_write_file().  What's the
>>>> justification for doing this?  The use of mnt_want_write_file() looks
>>>> necessary to me…
>>> 
>>> Hi Ted,
>>> 
>>>    mnt_want_write_file() and inode_lock is held before this function called now.
>>> Since both ioctl_set_flags and ext4_set_project() need call them.
>> 
>> I don't see any place in this patch where mnt_want_write_file() is
>> being called.  What am I missing?  And if there is a dependent patch
>> to this first patch in the patch series, please include it in this
>> patch series....  or least point it out after the --- list.
> 
> Sorry, I might not explain it clearly, here is current codes after applying patch:
> 
> 039                 err = mnt_want_write_file(filp);          ———————>called here, this is originally there for ext4_ioctl_setflags()
> 1040                 if (err)
> 1041                         return err;
> 1042 
> 1043                 inode_lock(inode);
> 1044                 err = ext4_ioctl_setattr_check_projid(inode, &fa);
> 1045                 if (err)
> 1046                         goto out;
> 1047                 flags = (ei->i_flags & ~EXT4_FL_XFLAG_VISIBLE) |
> 1048                          (flags & EXT4_FL_XFLAG_VISIBLE);
> 1049                 err = ext4_ioctl_setflags(inode, flags);
> 1050                 if (err)
> 1051                         goto out;
> 1052                 err = ext4_ioctl_setproject(filp, fa.fsx_projid);
> 1053 out:
> 1054                 inode_unlock(inode);
> 1055                 mnt_drop_write_file(filp);          ————————>dropped here.
> 1056                 return err; 
> 1057         }
> 
> Thanks,
> Shilong

Just a general ping for this, make sure you did not miss reply.
Since I saw you sent new pull request.

Is there anything more I could do? 


> 
>> 
>> Thanks,
>> 
>> 						- Ted
>