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Date: Tue, 6 Aug 2019 10:01:09 +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 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?
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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