Re: [PATCH 2/2] btrfs: tree-checker: Add check for INODE_REF

[Nikolay Borisov <nborisov@suse.com>]

On 26.08.19 г. 10:40 ч., Qu Wenruo wrote:
> For INODE_REF we will check:
> - Objectid (ino) against previous key
>   To detect missing INODE_ITEM.
> 
> - No overflow/padding in the data payload
>   Much like DIR_ITEM, but with less members to check.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  fs/btrfs/tree-checker.c | 53 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
> index 636ce1b4566e..3ce447eb591c 100644
> --- a/fs/btrfs/tree-checker.c
> +++ b/fs/btrfs/tree-checker.c
> @@ -842,6 +842,56 @@ static int check_inode_item(struct extent_buffer *leaf,
>  	return 0;
>  }
>  
> +#define inode_ref_err(fs_info, eb, slot, fmt, ...)		\
> +	inode_item_err(fs_info, eb, slot, fmt, __VA_ARGS__)

This define doesn't bring anything, just opencode the call to
inode_item_err directly.

> +static int check_inode_ref(struct extent_buffer *leaf,
> +			   struct btrfs_key *key, struct btrfs_key *prev_key,
> +			   int slot)
> +{
> +	struct btrfs_inode_ref *iref;
> +	unsigned long ptr;
> +	unsigned long end;
> +
> +	/* namelen can't be 0, so item_size == sizeof() is also invalid */
> +	if (btrfs_item_size_nr(leaf, slot) <= sizeof(*iref)) {
> +		inode_ref_err(fs_info, leaf, slot,
> +		"invalid item size, have %u expect (%zu, %u)",
> +			btrfs_item_size_nr(leaf, slot),
> +			sizeof(*iref), BTRFS_LEAF_DATA_SIZE(leaf->fs_info));
> +		return -EUCLEAN;
> +	}
> +
> +	ptr = btrfs_item_ptr_offset(leaf, slot);
> +	end = ptr + btrfs_item_size_nr(leaf, slot);
> +	while (ptr < end) {
> +		u16 namelen;
> +
> +		if (ptr + sizeof(iref) > end) {
> +			inode_ref_err(fs_info, leaf, slot,
> +		"inode ref overflow, ptr %lu end %lu inode_ref_size %zu",
> +				ptr, end, sizeof(iref));
> +			return -EUCLEAN;
> +		}
> +
> +		iref = (struct btrfs_inode_ref *)ptr;
> +		namelen = btrfs_inode_ref_name_len(leaf, iref);
> +		if (ptr + sizeof(*iref) + namelen > end) {
> +			inode_ref_err(fs_info, leaf, slot,
> +		"inode ref overflow, ptr %lu end %lu namelen %u",
> +				ptr, end, namelen);
> +			return -EUCLEAN;
> +		}
> +
> +		/*
> +		 * NOTE: In theory we should record all found index number
> +		 * to find any duplicated index. But that will be too time
> +		 * consuming for inodes with too many hard links.
> +		 */
> +		ptr += sizeof(*iref) + namelen;
> +	}
> +	return 0;
> +}
> +
>  /*
>   * Common point to switch the item-specific validation.
>   */
> @@ -864,6 +914,9 @@ static int check_leaf_item(struct extent_buffer *leaf,
>  	case BTRFS_XATTR_ITEM_KEY:
>  		ret = check_dir_item(leaf, key, prev_key, slot);
>  		break;
> +	case BTRFS_INODE_REF_KEY:
> +		ret = check_inode_ref(leaf, key, prev_key, slot);
> +		break;
>  	case BTRFS_BLOCK_GROUP_ITEM_KEY:
>  		ret = check_block_group_item(leaf, key, slot);
>  		break;
>