Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [f2fs-dev] [PATCH] f2fs: prevent compressed file from being
 disabled after releasing cblocks
To:     Daeho Jeong <daeho43@gmail.com>
CC:     Chao Yu <chao@kernel.org>, Daeho Jeong <daehojeong@google.com>,
        <kernel-team@android.com>, <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20200828054629.583577-1-daeho43@gmail.com>
 <61996dcd-6db1-13fc-8239-7e684f3ec49e@kernel.org>
 <CACOAw_wc29AROzFhcGyC73i_vYZC1NmHP60uQfP7X-j6y6=kSA@mail.gmail.com>
 <bd1a8ffa-83ff-b774-9bed-ed68025d0c7a@huawei.com>
 <CACOAw_y=O35_SFxdfsVER4+a+n-eE6f48NXF6CsAnj=Ms-dgkA@mail.gmail.com>
 <c4f58675-9df5-e3af-45fc-6fa924e3ee68@huawei.com>
 <CACOAw_wZFAyyt8qPCFd-LQKpMGa1moyOqSBpUnaeM0z2Y5Z+cA@mail.gmail.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <78ffaf17-56a0-32bd-0bcf-212333b52f06@huawei.com>
Date:   Mon, 31 Aug 2020 14:06:46 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <CACOAw_wZFAyyt8qPCFd-LQKpMGa1moyOqSBpUnaeM0z2Y5Z+cA@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2020/8/31 11:55, Daeho Jeong wrote:
>> - open(O_RDWR)
>> - ioctl(FS_IOC_SETFLAGS, F2FS_COMPR_FL)
>> - write()
>> - ioctl(RELEASE_COMPRESS_BLOCKS) -- inode is immutable now
>> - ioctl(FS_IOC_SETFLAGS, ~F2FS_COMPR_FL) -- Should we allow to update immutable inode?
>> as we know, normally, immutable inode should deny open(O_WRONLY or O_RDWR) and later update.
>>
> 
> For this case, with this patch we'll return -EINVAL for
> ioctl(FS_IOC_SETFLAGS, ~F2FS_COMPR_FL).
> I thought RESERVE_COMPRESS_BLOCKS ioctl is always required to get the
> file to normal mode after RELEASE_COMPRESS_BLOCKS is called.

That's an example, after compressed block release, shouldn't we disallow other ioctl
interface which updates immutable inode?

> .
>