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> --- v2: - add sb.required_features to store new incompatible feature's bit. 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 73e007dca3bb..9923902156f1 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_FEATURE 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..1ea24fce668e 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) & + ~F2FS_INCOMPATIBLE_FEATURE) { + f2fs_info(sbi, "Unsupported feature: %x: supported: %x", + le32_to_cpu(raw_super->required_features) ^ + F2FS_INCOMPATIBLE_FEATURE, + F2FS_INCOMPATIBLE_FEATURE); + 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 284738996028..a4bab287814f 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; -- 2.18.0.rc1