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Message-ID: <a155121f-2e1b-c3c5-17bb-b5ac3f4a7b1f@huawei.com>
Date: Tue, 6 Aug 2019 10:22:50 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>
CC: Chao Yu <chao@...nel.org>,
<linux-f2fs-devel@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 RESEND] f2fs: introduce sb.required_features to store
incompatible features
On 2019/8/6 10:11, Jaegeuk Kim wrote:
> On 08/06, Chao Yu wrote:
>> On 2019/8/6 9:24, Jaegeuk Kim wrote:
>>> On 08/06, Chao Yu wrote:
>>>> On 2019/8/6 8:35, Jaegeuk Kim wrote:
>>>>> On 08/02, Chao Yu wrote:
>>>>>> On 2019/8/2 6:35, Jaegeuk Kim wrote:
>>>>>>> On 08/01, Chao Yu wrote:
>>>>>>>> On 2019/8/1 12:22, Jaegeuk Kim wrote:
>>>>>>>>> On 07/31, Chao Yu wrote:
>>>>>>>>>> On 2019/7/31 7:18, Jaegeuk Kim wrote:
>>>>>>>>>>> On 07/29, Chao Yu wrote:
>>>>>>>>>>>> From: Chao Yu <yuchao0@...wei.com>
>>>>>>>>>>>>
>>>>>>>>>>>> Later after this patch was merged, all new incompatible feature's
>>>>>>>>>>>> bit should be added into sb.required_features field, and define new
>>>>>>>>>>>> feature function with F2FS_INCOMPAT_FEATURE_FUNCS() macro.
>>>>>>>>>>>>
>>>>>>>>>>>> Then during mount, we will do sanity check with enabled features in
>>>>>>>>>>>> image, if there are features in sb.required_features that kernel can
>>>>>>>>>>>> not recognize, just fail the mount.
>>>>>>>>>>>>
>>>>>>>>>>>> Signed-off-by: Chao Yu <yuchao0@...wei.com>
>>>>>>>>>>>> ---
>>>>>>>>>>>> v3:
>>>>>>>>>>>> - change commit title.
>>>>>>>>>>>> - fix wrong macro name.
>>>>>>>>>>>> fs/f2fs/f2fs.h | 15 +++++++++++++++
>>>>>>>>>>>> fs/f2fs/super.c | 10 ++++++++++
>>>>>>>>>>>> include/linux/f2fs_fs.h | 3 ++-
>>>>>>>>>>>> 3 files changed, 27 insertions(+), 1 deletion(-)
>>>>>>>>>>>>
>>>>>>>>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>>>>>>>>>> index a6eb828af57f..b8e17d4ddb8d 100644
>>>>>>>>>>>> --- a/fs/f2fs/f2fs.h
>>>>>>>>>>>> +++ b/fs/f2fs/f2fs.h
>>>>>>>>>>>> @@ -163,6 +163,15 @@ struct f2fs_mount_info {
>>>>>>>>>>>> #define F2FS_CLEAR_FEATURE(sbi, mask) \
>>>>>>>>>>>> (sbi->raw_super->feature &= ~cpu_to_le32(mask))
>>>>>>>>>>>>
>>>>>>>>>>>> +#define F2FS_INCOMPAT_FEATURES 0
>>>>>>>>>>>> +
>>>>>>>>>>>> +#define F2FS_HAS_INCOMPAT_FEATURE(sbi, mask) \
>>>>>>>>>>>> + ((sbi->raw_super->required_features & cpu_to_le32(mask)) != 0)
>>>>>>>>>>>> +#define F2FS_SET_INCOMPAT_FEATURE(sbi, mask) \
>>>>>>>>>>>> + (sbi->raw_super->required_features |= cpu_to_le32(mask))
>>>>>>>>>>>> +#define F2FS_CLEAR_INCOMPAT_FEATURE(sbi, mask) \
>>>>>>>>>>>> + (sbi->raw_super->required_features &= ~cpu_to_le32(mask))
>>>>>>>>>>>> +
>>>>>>>>>>>> /*
>>>>>>>>>>>> * Default values for user and/or group using reserved blocks
>>>>>>>>>>>> */
>>>>>>>>>>>> @@ -3585,6 +3594,12 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
>>>>>>>>>>>> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>>>>>>>>>>>> F2FS_FEATURE_FUNCS(casefold, CASEFOLD);
>>>>>>>>>>>>
>>>>>>>>>>>> +#define F2FS_INCOMPAT_FEATURE_FUNCS(name, flagname) \
>>>>>>>>>>>> +static inline int f2fs_sb_has_##name(struct f2fs_sb_info *sbi) \
>>>>>>>>>>>> +{ \
>>>>>>>>>>>> + return F2FS_HAS_INCOMPAT_FEATURE(sbi, F2FS_FEATURE_##flagname); \
>>>>>>>>>>>> +}
>>>>>>>>>>>> +
>>>>>>>>>>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>>>>>>>>>> static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi, int devi,
>>>>>>>>>>>> block_t blkaddr)
>>>>>>>>>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>>>>>>>>>> index 5540fee0fe3f..3701dcce90e6 100644
>>>>>>>>>>>> --- a/fs/f2fs/super.c
>>>>>>>>>>>> +++ b/fs/f2fs/super.c
>>>>>>>>>>>> @@ -2513,6 +2513,16 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
>>>>>>>>>>>> return -EINVAL;
>>>>>>>>>>>> }
>>>>>>>>>>>>
>>>>>>>>>>>> + /* check whether current kernel supports all features on image */
>>>>>>>>>>>> + if (le32_to_cpu(raw_super->required_features) &
>>>>>>>>>>>
>>>>>>>>>>> ...
>>>>>>>>>>> #define F2FS_FEATURE_VERITY 0x0400 /* reserved */
>>>>>>>>>>> ...
>>>>>>>>>>> #define F2FS_FEATURE_CASEFOLD 0x1000
>>>>>>>>>>> #define F2FS_FEATURE_SUPPORT 0x1BFF
>>>>>>>>>>>
>>>>>>>>>>> if (le32_to_cpu(raw_super->required_features) & ~F2FS_FEATURE_SUPPORT) {
>>>>>>>>>>> ...
>>>>>>>>>>> return -EINVAL;
>>>>>>>>>>> }
>>>>>>>>>>
>>>>>>>>>> Um, I thought .required_features are used to store new feature flags from 0x0.
>>>>>>>>>>
>>>>>>>>>> All 'F2FS_FEATURE_SUPPORT' bits should be stored in sb.feature instead of
>>>>>>>>>> sb.required_features, I'm confused...
>>>>>>>>>
>>>>>>>>> I'm thinking,
>>>>>>>>>
>>>>>>>>> f2fs-tools sb->required_features f2fs F2FS_FEATURE_SUPPORT
>>>>>>>>> v0 0 v0 no_check -> ok
>>>>>>>>> v1 0x1BFF v0 no_check -> ok
>>>>>>>>> v0 0 v1 0x1BFF -> ok
>>>>>>>>> v1 0x1BFF v1 0x1BFF -> ok
>>>>>>>>> v2 0x3BFF v1 0x1BFF -> fail
>>>>>>>>> v1 0x1BFF v2 0x3BFF -> ok
>>>>>>>>> v2 0x3BFF v2 0x3BFF -> ok
>>>>>>>>
>>>>>>>> I see, it's a bit waste for 0x1FFF low bits in sb->required_features. Why not
>>>>>>>> leaving 0x0FFF in sb->feature w/o sanity check. And make all new incompatible
>>>>>>>> features (including casefold) adding into sb->required_features.
>>>>>>>
>>>>>>> I don't think we can define like this, and we still have 32bits feature filed.
>>>>>>> This would give another confusion to understand. VERITY is reserved only now.
>>>>>>>
>>>>>>> #define F2FS_FEATURE_CASEFOLD 0x0001
>>>>>>
>>>>>> Oops, so you want to make .required_features being almost a mirror of .feature,
>>>>>> and do sanity check on it... I can see now. :P
>>>>>>
>>>>>> If so, why not just use .feature:
>>>>>
>>>>> Sometimes, we don't need to set the flag, but not required at some point.
>>>>> (e.g., verify)
>>>>
>>>> Sorry, I'm not sure whether I have understood your point... :(
>>>>
>>>> IIUC of your point, we have defined F2FS_FEATURE_SUPPORT (0x0BFF) which excludes
>>>> F2FS_FEATURE_VERITY (0x0400) feature bit, then once verity feature merged in
>>>> kernel, we can add it into F2FS_FEATURE_SUPPORT, any problem we may face here?
>>>
>>> I was thinking the cases like "don't care features" made by mkfs. For example,
>>> mkfs can set F2FS_FEATURE_BLKZONED, which doesn't need f2fs being supported.
>>
>> Yes, I can understand this.
>>
>> So F2FS_FEATURE_SUPPORT can exclude them directly?
>
> No, I'd like to control it via mkfs. Kernel always needs to say what they can
> support, IIUC your point.
Oh, it's different macros, we will define F2FS_INCOMPAT_FEATURE_SUPPORT 0x19B9,
and F2FS_ALL_FEATURE_SUPPORT (0x0001 | 0x0002 ... ).
In sanity check function, we only check .feature with
F2FS_INCOMPAT_FEATURE_SUPPORT. And of course, meanwhile kernel will say it
supports features in F2FS_ALL_FEATURE_SUPPORT.
Thanks,
>
>>
>> excluded:
>>
>> #define F2FS_FEATURE_BLKZONED 0x0002
>> #define F2FS_FEATURE_ATOMIC_WRITE 0x0004
>> #define F2FS_FEATURE_LOST_FOUND 0x0200
>>
>> included:
>>
>> #define F2FS_FEATURE_ENCRYPT 0x0001
>> #define F2FS_FEATURE_EXTRA_ATTR 0x0008
>> #define F2FS_FEATURE_PRJQUOTA 0x0010
>> #define F2FS_FEATURE_INODE_CHKSUM 0x0020
>> #define F2FS_FEATURE_FLEXIBLE_INLINE_XATTR 0x0040
>> #define F2FS_FEATURE_QUOTA_INO 0x0080
>> #define F2FS_FEATURE_INODE_CRTIME 0x0100
>> #define F2FS_FEATURE_SB_CHKSUM 0x0800
>> //#define F2FS_FEATURE_VERITY 0x0400 /* reserved */
>> #define F2FS_FEATURE_CASEFOLD 0x1000
>>
>> #define F2FS_FEATURE_SUPPORT 0x19B9
>>
>> Thanks,
>>
>>>
>>>>
>>>> Thanks
>>>>
>>>>>
>>>>>>
>>>>>> kernel tool
>>>>>> v5.2 .. 1.12
>>>>>> #define F2FS_FEATURE_SUPPORT 0x0BFF
>>>>>>
>>>>>> v5.3 .. 1.13
>>>>>> #define F2FS_FEATURE_CASEFOLD 0x1000
>>>>>> #define F2FS_FEATURE_SUPPORT 0x1BFF
>>>>>>
>>>>>> v5.4 .. 1.14
>>>>>> #define F2FS_FEATURE_CASEFOLD 0x1000
>>>>>> #define F2FS_FEATURE_COMPRESS 0x2000
>>>>>> #define F2FS_FEATURE_SUPPORT 0x3BFF
>>>>>>
>>>>>> f2fs-tools sb->feature f2fs F2FS_FEATURE_SUPPORT
>>>>>>
>>>>>> [enable all features in tools]
>>>>>> v1.12 0x0BFF v5.2 no_check -> ok
>>>>>> v1.12 0x0BFF v5.3 0x1BFF -> ok
>>>>>> v1.12 0x0BFF v5.4 0x3BFF -> ok
>>>>>>
>>>>>> v1.13 0x1BFF v5.2 that's issue we need to fix
>>>>>> v1.13 0x1BFF v5.3 0x1BFF -> ok
>>>>>> v1.13 0x1BFF v5.4 0x3BFF -> ok
>>>>>>
>>>>>> v1.14 0x3BFF v5.2 that's issue we need to fix
>>>>>> v1.14 0x3BFF v5.3 0x1BFF -> fail
>>>>>> v1.14 0x3BFF v5.4 0x3BFF -> ok
>>>>>>
>>>>>> Or am I missing something?
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Then that would be:
>>>>>>>>
>>>>>>>> kernel tool
>>>>>>>> v5.2 .. 1.12
>>>>>>>> #define F2FS_FEATURE_SUPPORT 0x0000
>>>>>>>>
>>>>>>>> v5.3 .. 1.13
>>>>>>>> #define F2FS_FEATURE_CASEFOLD 0x0001
>>>>>>>> #define F2FS_FEATURE_SUPPORT 0x0001
>>>>>>>>
>>>>>>>> v5.4 .. 1.14
>>>>>>>> #define F2FS_FEATURE_CASEFOLD 0x0001
>>>>>>>> #define F2FS_FEATURE_COMPRESS 0x0002
>>>>>>>> #define F2FS_FEATURE_SUPPORT 0x0003
>>>>>>>>
>>>>>>>> f2fs-tools sb->required_features f2fs F2FS_FEATURE_SUPPORT
>>>>>>>>
>>>>>>>> v1.12 0x0000 v5.2 no_check -> ok
>>>>>>>> v1.12 0x0000 v5.3 0x0001 -> ok
>>>>>>>> v1.12 0x0000 v5.4 0x0003 -> ok
>>>>>>>>
>>>>>>>> v1.13 0x0001 v5.2 that's issue we need to fix
>>>>>>>> v1.13 0x0001 v5.3 0x0001 -> ok
>>>>>>>> v1.13 0x0001 v5.4 0x0003 -> ok
>>>>>>>>
>>>>>>>> v1.14 0x0003 v5.2 that's issue we need to fix
>>>>>>>> v1.14 0x0003 v5.3 0x0001 -> fail
>>>>>>>> v1.14 0x0003 v5.4 0x0003 -> ok
>>>>>>>>
>>>>>>>> And all compatible features can be added into sb->feature[_VERITY, ....].
>>>>>>>>
>>>>>>>> Would that okay to you?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>> + ~F2FS_INCOMPAT_FEATURES) {
>>>>>>>>>>>> + f2fs_info(sbi, "Unsupported feature: %x: supported: %x",
>>>>>>>>>>>> + le32_to_cpu(raw_super->required_features) ^
>>>>>>>>>>>> + F2FS_INCOMPAT_FEATURES,
>>>>>>>>>>>> + F2FS_INCOMPAT_FEATURES);
>>>>>>>>>>>> + return -EINVAL;
>>>>>>>>>>>> + }
>>>>>>>>>>>> +
>>>>>>>>>>>> /* Check checksum_offset and crc in superblock */
>>>>>>>>>>>> if (__F2FS_HAS_FEATURE(raw_super, F2FS_FEATURE_SB_CHKSUM)) {
>>>>>>>>>>>> crc_offset = le32_to_cpu(raw_super->checksum_offset);
>>>>>>>>>>>> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
>>>>>>>>>>>> index a2b36b2e286f..4141be3f219c 100644
>>>>>>>>>>>> --- a/include/linux/f2fs_fs.h
>>>>>>>>>>>> +++ b/include/linux/f2fs_fs.h
>>>>>>>>>>>> @@ -117,7 +117,8 @@ struct f2fs_super_block {
>>>>>>>>>>>> __u8 hot_ext_count; /* # of hot file extension */
>>>>>>>>>>>> __le16 s_encoding; /* Filename charset encoding */
>>>>>>>>>>>> __le16 s_encoding_flags; /* Filename charset encoding flags */
>>>>>>>>>>>> - __u8 reserved[306]; /* valid reserved region */
>>>>>>>>>>>> + __le32 required_features; /* incompatible features to old kernel */
>>>>>>>>>>>> + __u8 reserved[302]; /* valid reserved region */
>>>>>>>>>>>> __le32 crc; /* checksum of superblock */
>>>>>>>>>>>> } __packed;
>>>>>>>>>>>>
>>>>>>>>>>>> --
>>>>>>>>>>>> 2.22.0
>>>>>>>>>>> .
>>>>>>>>>>>
>>>>>>>>> .
>>>>>>>>>
>>>>>>> .
>>>>>>>
>>>>> .
>>>>>
>>> .
>>>
> .
>
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