Re: [f2fs-dev] [PATCH] f2fs: prevent mounting devices with unsupported features

[Chao Yu <yuchao0@huawei.com>]

Hi Ju Hyung,

On 2021/4/5 16:40, Park Ju Hyung wrote:
> Mounting f2fs devices with future options leads to unwanted behaviors
> incurring errors and data destruction.
> 
> Implement a long overdue safeguard to prevent mounting devices with
> unsupported features.
> 
> This can be further extended to allow read-only mounts on certain
> incompatible features, but that doesn't seem necessary for now with
> how f2fs features has been added.

Thanks for the patch!

I have a RFC patch for this issue, but the patch doesn't being merged,
IIRC, Jaegeuk and I have divergence on implementation details, maybe we
could continue the discussion and work right now. :)

https://lkml.org/lkml/2019/7/29/623

Thanks,

> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
> ---
>   fs/f2fs/f2fs.h  | 11 +++++++++++
>   fs/f2fs/super.c | 10 ++++++++++
>   2 files changed, 21 insertions(+)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index e2d302ae3a46..12d274492d6f 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -153,6 +153,9 @@ struct f2fs_mount_info {
>   	unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN];	/* extensions */
>   };
>   
> +/*
> + * All features listed here should be appended to F2FS_SUPPORTED_FEATURES
> + */
>   #define F2FS_FEATURE_ENCRYPT		0x0001
>   #define F2FS_FEATURE_BLKZONED		0x0002
>   #define F2FS_FEATURE_ATOMIC_WRITE	0x0004
> @@ -168,6 +171,14 @@ struct f2fs_mount_info {
>   #define F2FS_FEATURE_CASEFOLD		0x1000
>   #define F2FS_FEATURE_COMPRESSION	0x2000
>   
> +/* Currently supported features by this version of f2fs */
> +#define F2FS_SUPPORTED_FEATURES \
> +	(F2FS_FEATURE_ENCRYPT | F2FS_FEATURE_BLKZONED | F2FS_FEATURE_ATOMIC_WRITE | \
> +	 F2FS_FEATURE_EXTRA_ATTR | F2FS_FEATURE_PRJQUOTA | F2FS_FEATURE_INODE_CHKSUM | \
> +	 F2FS_FEATURE_FLEXIBLE_INLINE_XATTR | F2FS_FEATURE_QUOTA_INO | F2FS_FEATURE_INODE_CRTIME | \
> +	 F2FS_FEATURE_LOST_FOUND | F2FS_FEATURE_VERITY | F2FS_FEATURE_SB_CHKSUM | \
> +	 F2FS_FEATURE_CASEFOLD | F2FS_FEATURE_COMPRESSION)
> +
>   #define __F2FS_HAS_FEATURE(raw_super, mask)				\
>   	((raw_super->feature & cpu_to_le32(mask)) != 0)
>   #define F2FS_HAS_FEATURE(sbi, mask)	__F2FS_HAS_FEATURE(sbi->raw_super, mask)
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 82592b19b4e0..91d77985cf9b 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -3610,6 +3610,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>   	int recovery, i, valid_super_block;
>   	struct curseg_info *seg_i;
>   	int retry_cnt = 1;
> +	__le32 unsupported;
>   
>   try_onemore:
>   	err = -EINVAL;
> @@ -3647,6 +3648,15 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>   	sb->s_fs_info = sbi;
>   	sbi->raw_super = raw_super;
>   
> +	/* check supported features */
> +	unsupported = raw_super->feature & ~F2FS_SUPPORTED_FEATURES;
> +	if (unsupported) {
> +		f2fs_err(sbi, "unsupported features: 0x%x\n", unsupported);
> +		f2fs_err(sbi, "please update your kernel or adjust the mkfs.f2fs option\n", unsupported);
> +		err = -EOPNOTSUPP;
> +		goto free_sb_buf;
> +	}
> +
>   	/* precompute checksum seed for metadata */
>   	if (f2fs_sb_has_inode_chksum(sbi))
>   		sbi->s_chksum_seed = f2fs_chksum(sbi, ~0, raw_super->uuid,
> 


_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel