Re: [PATCH v3] btrfs: Add chunk type check in read a chunk

[Nikolay Borisov <nborisov@suse.com>]

On  4.07.2018 13:16, Gu Jinxiang wrote:
> Reported in https://bugzilla.kernel.org/show_bug.cgi?id=199839,
> which has a invalid chunk, not return error opportunlly.
> 
> Add chunk type check in btrfs_check_chunk_valid,
> to make error be returned in advance.
> 
> Reported-by: Xu Wen <wen.xu@gatech.edu>
> Signed-off-by: Gu Jinxiang <gujx@cn.fujitsu.com>
> Reviewed-by: Qu Wenruo <wqu@suse.com>
> ---
> changelog:
> v3:
> deal with comment by Nikolay Borisov, change the error message
> more appropriate.
> 
> v2:
> deal with comment by Qu, add precise check for chunk type.
> 
>  fs/btrfs/volumes.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index b33bf29130b6..deea169cc276 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -6401,6 +6401,8 @@ static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info,
>  	u16 num_stripes;
>  	u16 sub_stripes;
>  	u64 type;
> +	u64 features;
> +	int mixed = 0;
>  
>  	length = btrfs_chunk_length(leaf, chunk);
>  	stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
> @@ -6439,6 +6441,33 @@ static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info,
>  			  btrfs_chunk_type(leaf, chunk));
>  		return -EIO;
>  	}
> +
> +	if (!(type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
> +		btrfs_err(fs_info, "missing chunk type flag: %llu", type);
> +		return -EIO;
> +	}
> +
> +	if ((type & BTRFS_BLOCK_GROUP_SYSTEM) &&
> +	(type & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA))) {
> +		btrfs_err(fs_info,
> +"system chunk type, meanwhile with metadata or data chunk type flag: %llu",
> +				type);

That's rather cumbersomely worded, why not simply "Invalid chunk type
detected"

> +		return -EIO;
> +	}
> +
> +	features = btrfs_super_incompat_flags(fs_info->super_copy);
> +	if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
> +		mixed = 1;
> +
> +	if (!mixed) {
> +		if (type &
> +		(BTRFS_BLOCK_GROUP_METADATA & BTRFS_BLOCK_GROUP_DATA)) {
> +			btrfs_err(fs_info,
> +			"mixed chunk type flag in non-mixed mode: %llu", type);
> +			return -EIO;
> +		}
> +	}
> +
>  	if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) ||
>  	    (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) ||
>  	    (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
>