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Subject: Re: [f2fs-dev] [PATCH v2 2/2] f2fs: fix compat F2FS_IOC_{MOVE,
 GARBAGE_COLLECT}_RANGE
To:     Eric Biggers <ebiggers@kernel.org>
CC:     <jaegeuk@kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20201104064310.15769-1-yuchao0@huawei.com>
 <20201104064310.15769-2-yuchao0@huawei.com>
 <20201104180153.GB846@sol.localdomain>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <2bec3d16-e920-12b9-562d-0e055c1af28e@huawei.com>
Date:   Thu, 5 Nov 2020 09:00:59 +0800
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On 2020/11/5 2:01, Eric Biggers wrote:
> On Wed, Nov 04, 2020 at 02:43:10PM +0800, Chao Yu wrote:
>> +static int f2fs_ioc_gc_range(struct file *filp, unsigned long arg)
>> +{
>> +	struct f2fs_gc_range range;
>> +	struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(filp));
>> +
>> +	if (!capable(CAP_SYS_ADMIN))
>> +		return -EPERM;
>> +	if (f2fs_readonly(sbi->sb))
>> +		return -EROFS;
>> +	if (copy_from_user(&range, (struct f2fs_gc_range __user *)arg,
>> +							sizeof(range)))
>> +		return -EFAULT;
>> +
>> +	return __f2fs_ioc_gc_range(filp, &range);
>> +}
> [...]
>>   #ifdef CONFIG_COMPAT
>> +static int f2fs_compat_ioc_gc_range(struct file *file, unsigned long arg)
>> +{
>> +	struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(file));
>> +	struct compat_f2fs_gc_range __user *urange;
>> +	struct f2fs_gc_range range;
>> +	int err;
>> +
>> +	if (unlikely(f2fs_cp_error(sbi)))
>> +		return -EIO;
>> +	if (!f2fs_is_checkpoint_ready(sbi))
>> +		return -ENOSPC;
>> +	if (!capable(CAP_SYS_ADMIN))
>> +		return -EPERM;
>> +	if (f2fs_readonly(sbi->sb))
>> +		return -EROFS;
>> +
>> +	urange = compat_ptr(arg);
>> +	err = get_user(range.sync, &urange->sync);
>> +	err |= get_user(range.start, &urange->start);
>> +	err |= get_user(range.len, &urange->len);
>> +	if (err)
>> +		return -EFAULT;
>> +
>> +	return __f2fs_ioc_gc_range(file, &range);
>> +}
> 
> It would be better to have __f2fs_ioc_gc_range() handle the f2fs_cp_error(),
> f2fs_is_checkpoint_ready(), capable(), and f2fs_readonly() checks, so that they
> don't have to be duplicated in the native and compat cases.
> 
> Similarly for "move range".

Will clean up in v3.

Thanks,

> 
> - Eric
> .
>