From: Chao Yu <yuchao0@huawei.com>
To: Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>
Cc: Eric Biggers <ebiggers@kernel.org>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
Michael Halcrow <mhalcrow@google.com>,
<linux-kernel@vger.kernel.org>,
<linux-f2fs-devel@lists.sourceforge.net>,
<linux-fscrypt@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
<linux-integrity@vger.kernel.org>, <linux-ext4@vger.kernel.org>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Victor Hsieh <victorhsieh@google.com>
Subject: Re: [f2fs-dev] [RFC PATCH 10/10] f2fs: fs-verity support
Date: Tue, 28 Aug 2018 17:20:01 +0800 [thread overview]
Message-ID: <63a19512-e938-d239-9e3c-f6ecc479478c@huawei.com> (raw)
In-Reply-To: <20180828072756.GC29049@jaegeuk-macbookpro.roam.corp.google.com>
On 2018/8/28 15:27, Jaegeuk Kim wrote:
> On 08/27, Chao Yu wrote:
>> Hi Eric,
>>
>> On 2018/8/27 1:35, Eric Biggers wrote:
>>> Hi Chao,
>>>
>>> On Sat, Aug 25, 2018 at 01:54:08PM +0800, Chao Yu wrote:
>>>> On 2018/8/25 0:16, Eric Biggers wrote:
>>>>> From: Eric Biggers <ebiggers@google.com>
>>>>> #ifdef CONFIG_F2FS_CHECK_FS
>>>>> #define f2fs_bug_on(sbi, condition) BUG_ON(condition)
>>>>> #else
>>>>> @@ -146,7 +149,7 @@ struct f2fs_mount_info {
>>>>> #define F2FS_FEATURE_QUOTA_INO 0x0080
>>>>> #define F2FS_FEATURE_INODE_CRTIME 0x0100
>>>>> #define F2FS_FEATURE_LOST_FOUND 0x0200
>>>>> -#define F2FS_FEATURE_VERITY 0x0400 /* reserved */
>>>>> +#define F2FS_FEATURE_VERITY 0x0400
>>>>>
>>>>> #define F2FS_HAS_FEATURE(sb, mask) \
>>>>> ((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0)
>>>>> @@ -598,7 +601,7 @@ enum {
>>>>> #define FADVISE_ENC_NAME_BIT 0x08
>>>>> #define FADVISE_KEEP_SIZE_BIT 0x10
>>>>> #define FADVISE_HOT_BIT 0x20
>>>>> -#define FADVISE_VERITY_BIT 0x40 /* reserved */
>>>>> +#define FADVISE_VERITY_BIT 0x40
>>>>
>>>> As I suggested before, how about moving f2fs' verity_bit from i_fadvise to more
>>>> generic i_flags field like ext4, so we can a) remaining more bits for those
>>>> demands which really need file advise fields. b) using i_flags bits keeping line
>>>> with ext4. Not sure, if user want to know whether the file is verity one, it
>>>> will be easy for f2fs to export the status through FS_IOC_SETFLAGS.
>>>>
>>>> #define EXT4_VERITY_FL 0x00100000 /* Verity protected inode */
>>>>
>>>> #define F2FS_VERITY_FL 0x00100000 /* Verity protected inode */
>>>>
>>>
>>> I don't like using i_advise much either, but I actually don't see either
>>> location being much better than the other at the moment. The real problem is an
>>> artificial one: the i_flags in f2fs's on-disk format are being assumed to use
>>
>> Yeah, but since most copied flags from vfs/ext4 are not actually used in f2fs,
>> also 0x00100000 bit is not used now, so we can just define it now directly for
>> verity bit.
>>
>> Cleanup and remapping in ioctl interface for those unused flags, we can do it
>> latter?
>
> No, it was reserved by f2fs-tools,
That's not a problem, since we didn't use that reserved bit in any of images
now, there is no backward compatibility issue.
> and I think this should be aligned to the encryption bit.
Alright, we could, but if so, i_advise will run out of space earlier, after that
we have to add real advice bit into i_inline or i_flags, that would be a little
weird.
For encryption bit, as a common vfs feature flag, in the beginning of encryption
development, it will be better to set it into i_flags, IMO, but now, we have to
keep it as it was.
> Moreover, we guarantee i_flags less strictly from power-cut than i_advise.
IMO, in power-cut scenario, it needs to keep both i_flags and i_advise being
recoverable strictly. Any condition that we can not recover i_flags?
Thanks,
>
>>
>> Thanks,
>>
>>> the same numbering scheme as ext4's on-disk format, which makes it seem that
>>> they have to be in sync, and that all new ext4 flags (say, EA_INODE) also
>>> reserve bits in f2fs and vice versa, when they in fact do not. Instead, f2fs
>>> should use its own numbering for its i_flags, and it should map them to/from
>>> whatever is needed for common APIs like FS_IOC_{GET,SET}FLAGS and
>>> FS_IOC_FS{GET,SET}XATTR.
>>>
>>> So putting the verity flag in *either* location (i_advise or i_flags) is just
>>> kicking the can down the road. If I get around to it I will send a patch that
>>> cleans up the f2fs flags properly...>
>>> Thanks,
>>>
>>> - Eric
>>>
>>> ------------------------------------------------------------------------------
>>> Check out the vibrant tech community on one of the world's most
>>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>>> _______________________________________________
>>> Linux-f2fs-devel mailing list
>>> Linux-f2fs-devel@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>>>
>
> .
>
next prev parent reply other threads:[~2018-08-28 9:20 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 16:16 [RFC PATCH 00/10] fs-verity: filesystem-level integrity protection Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 01/10] fs-verity: add setup code, UAPI, and Kconfig Eric Biggers
2018-08-24 17:28 ` Randy Dunlap
2018-08-24 17:42 ` Colin Walters
2018-08-24 22:45 ` Theodore Y. Ts'o
2018-08-25 4:48 ` Eric Biggers
2018-09-14 13:15 ` Colin Walters
2018-09-14 16:21 ` Eric Biggers
2018-09-15 15:27 ` Theodore Y. Ts'o
2018-08-26 16:22 ` Chuck Lever
2018-08-26 17:17 ` Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 02/10] fs-verity: add data verification hooks for ->readpages() Eric Biggers
2018-08-25 2:29 ` [f2fs-dev] " Gao Xiang
2018-08-25 3:45 ` Theodore Y. Ts'o
2018-08-25 4:00 ` Gao Xiang
2018-08-25 5:06 ` Theodore Y. Ts'o
2018-08-25 7:33 ` Gao Xiang
2018-08-25 7:55 ` Gao Xiang
2018-08-25 4:16 ` Eric Biggers
2018-08-25 6:31 ` Gao Xiang
2018-08-25 7:18 ` Eric Biggers
2018-08-25 7:43 ` Gao Xiang
2018-08-25 17:06 ` Theodore Y. Ts'o
2018-08-26 13:44 ` Gao Xiang
2018-09-02 2:35 ` Olof Johansson
2018-08-26 15:55 ` Chuck Lever
2018-08-26 17:04 ` Eric Biggers
2018-08-26 17:44 ` Gao Xiang
2018-08-24 16:16 ` [RFC PATCH 03/10] fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 04/10] fs-verity: implement FS_IOC_MEASURE_VERITY ioctl Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 05/10] fs-verity: add SHA-512 support Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 06/10] fs-verity: add CRC-32C support Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 07/10] fs-verity: support builtin file signatures Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 08/10] ext4: add basic fs-verity support Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 09/10] ext4: add fs-verity read support Eric Biggers
2018-08-24 16:16 ` [RFC PATCH 10/10] f2fs: fs-verity support Eric Biggers
2018-08-25 5:54 ` [f2fs-dev] " Chao Yu
2018-08-26 17:35 ` Eric Biggers
2018-08-27 15:54 ` Chao Yu
2018-08-28 7:27 ` Jaegeuk Kim
2018-08-28 9:20 ` Chao Yu [this message]
2018-08-28 17:01 ` Jaegeuk Kim
2018-08-29 1:22 ` Chao Yu
2018-08-29 1:43 ` Jaegeuk Kim
2018-08-31 20:05 ` [RFC PATCH 00/10] fs-verity: filesystem-level integrity protection Jan Lübbe
2018-08-31 21:39 ` Eric Biggers
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