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Subject: Re: [f2fs-dev] [PATCH v2] f2fs: change the way of handling range.len
 in F2FS_IOC_SEC_TRIM_FILE
To:     Daeho Jeong <daeho43@gmail.com>
CC:     Jaegeuk Kim <jaegeuk@kernel.org>,
        Daeho Jeong <daehojeong@google.com>, <kernel-team@android.com>,
        <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20200713031252.3873546-1-daeho43@gmail.com>
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 <3b02263d-a5e1-136c-40ed-514d34e4c895@huawei.com>
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 <f4a594a1-464f-3a74-90cb-fd536bed9962@huawei.com>
 <CACOAw_w3OWDVXSYHuTEEVv1HaBZir1CWcRAmxOt00MB4vXBKVg@mail.gmail.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <1d84bc01-fece-df55-6e33-07a705cfb432@huawei.com>
Date:   Wed, 15 Jul 2020 15:17:54 +0800
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On 2020/7/15 14:54, Daeho Jeong wrote:
> You mean we can support ZEROOUT option only for encrypted files of
> non-multidevice f2fs,
> and return -EOPNOTSUPP in the multidevice case, right now?

Yes, something like:

f2fs_sec_trim_file()

if ((range.flags & F2FS_TRIM_FILE_ZEROOUT) &&
	f2fs_encrypted_file() && f2fs_is_multi_device())
	return -EOPNOTSUPP;


f2fs_secure_erase()

if (!ret && (flags & F2FS_TRIM_FILE_ZEROOUT)) {
	if (f2fs_encrypted_file()) {
		if (fscrypt_inode_uses_fs_layer_crypto)
			ret = fscrypt_zeroout_range();
		else
			ret = fscrypt_zeroout_range_inline_crypt();
	} else {
		ret = blkdev_issue_zeroout();
	}
}

Thanks,

> 
> 2020년 7월 15일 (수) 오후 3:17, Chao Yu <yuchao0@huawei.com>님이 작성:
>>
>> On 2020/7/15 12:06, Daeho Jeong wrote:
>>> We could use fscrypt_zeroout_range() for an encrypted file.
>>> But, one problem is fscrypt_zeroout_range() assumes that filesystems
>>> only use a single block device.
>>> It means it doesn't receive bdev as a parameter.
>>> How about changing the interface of fscrypt_zeroout_range() first and using it?
>>
>> Yes, please limited to use fscrypt_zeroout_range() on non-multidevice f2fs image
>> first, we can add a condition to check that in the beginning of ioctl interface,
>> once fscrypt_zeroout_range() accepts bdev as parameter, we can remove that limitation.
>>
>> Thanks,
>>
>>>
>>> 2020년 7월 14일 (화) 오후 9:36, Chao Yu <yuchao0@huawei.com>님이 작성:
>>>>
>>>> On 2020/7/14 2:11, Jaegeuk Kim wrote:
>>>>> Hi Daeho,
>>>>>
>>>>> Please take a look at this.
>>>>>
>>>>> https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=35245180459aebf6d70fde88a538f0400a794aa6
>>>>
>>>> I'm curious about what will happen if we call
>>>> sec_trim_file(F2FS_TRIM_FILE_ZEROOUT) on an encrypted file, will
>>>> it use zero bits covering encrypted data on disk?
>>>>
>>>> Thanks,
>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> On 07/13, Daeho Jeong wrote:
>>>>>> From: Daeho Jeong <daehojeong@google.com>
>>>>>>
>>>>>> Changed the way of handling range.len of F2FS_IOC_SEC_TRIM_FILE.
>>>>>>  1. Added -1 value support for range.len to secure trim the whole blocks
>>>>>>     starting from range.start regardless of i_size.
>>>>>>  2. If the end of the range passes over the end of file, it means until
>>>>>>     the end of file (i_size).
>>>>>>  3. ignored the case of that range.len is zero to prevent the function
>>>>>>     from making end_addr zero and triggering different behaviour of
>>>>>>     the function.
>>>>>>
>>>>>> Signed-off-by: Daeho Jeong <daehojeong@google.com>
>>>>>> ---
>>>>>> Changes in v2:
>>>>>>  - Changed -1 range.len option to mean the whole blocks starting from
>>>>>>    range.start regardless of i_size
>>>>>> ---
>>>>>>  fs/f2fs/file.c | 23 ++++++++++++-----------
>>>>>>  1 file changed, 12 insertions(+), 11 deletions(-)
>>>>>>
>>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>>>> index 368c80f8e2a1..2485841e3b2d 100644
>>>>>> --- a/fs/f2fs/file.c
>>>>>> +++ b/fs/f2fs/file.c
>>>>>> @@ -3792,7 +3792,7 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
>>>>>>      pgoff_t index, pg_end;
>>>>>>      block_t prev_block = 0, len = 0;
>>>>>>      loff_t end_addr;
>>>>>> -    bool to_end;
>>>>>> +    bool to_end = false;
>>>>>>      int ret = 0;
>>>>>>
>>>>>>      if (!(filp->f_mode & FMODE_WRITE))
>>>>>> @@ -3813,23 +3813,23 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
>>>>>>      file_start_write(filp);
>>>>>>      inode_lock(inode);
>>>>>>
>>>>>> -    if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode)) {
>>>>>> +    if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode) ||
>>>>>> +                    range.start >= inode->i_size) {
>>>>>>              ret = -EINVAL;
>>>>>>              goto err;
>>>>>>      }
>>>>>>
>>>>>> -    if (range.start >= inode->i_size) {
>>>>>> -            ret = -EINVAL;
>>>>>> +    if (range.len == 0)
>>>>>>              goto err;
>>>>>> -    }
>>>>>>
>>>>>> -    if (inode->i_size - range.start < range.len) {
>>>>>> -            ret = -E2BIG;
>>>>>> -            goto err;
>>>>>> +    if (inode->i_size - range.start > range.len) {
>>>>>> +            end_addr = range.start + range.len;
>>>>>> +    } else {
>>>>>> +            end_addr = range.len == (u64)-1 ?
>>>>>> +                    sbi->sb->s_maxbytes : inode->i_size;
>>>>>> +            to_end = true;
>>>>>>      }
>>>>>> -    end_addr = range.start + range.len;
>>>>>>
>>>>>> -    to_end = (end_addr == inode->i_size);
>>>>>>      if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
>>>>>>                      (!to_end && !IS_ALIGNED(end_addr, F2FS_BLKSIZE))) {
>>>>>>              ret = -EINVAL;
>>>>>> @@ -3846,7 +3846,8 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
>>>>>>      down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>>>>>>      down_write(&F2FS_I(inode)->i_mmap_sem);
>>>>>>
>>>>>> -    ret = filemap_write_and_wait_range(mapping, range.start, end_addr - 1);
>>>>>> +    ret = filemap_write_and_wait_range(mapping, range.start,
>>>>>> +                    to_end ? LLONG_MAX : end_addr - 1);
>>>>>>      if (ret)
>>>>>>              goto out;
>>>>>>
>>>>>> --
>>>>>> 2.27.0.383.g050319c2ae-goog
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Linux-f2fs-devel mailing list
>>>>> Linux-f2fs-devel@lists.sourceforge.net
>>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>>>>> .
>>>>>
>>> .
>>>
> .
>