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 <yuch...@huawei.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 <yuch...@huawei.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. 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 >>> . >>> > . >