Re: [nft] deleting chains and verdict map entries in the same transaction

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Mon, Sep 07, 2015 at 11:45:42AM +0200, Andreas Schultz wrote:
> Hi,
> 
> I'm trying to delete a verdict map entry and the chain it points to
> in the same nft transaction. This currently fails with:
> 
>    Error: Could not process rule: Device or resource busy
> 
> existing rules:
> 
>  nft list table mangle
> table ip mangle {
> 	map client_to_any { 
> 		type mark : verdict
> 		elements = { 0x00000080 : jump BIn_1, 0x00000100 : jump BIn_2}
> 	}
> 
> 	map any_to_client { 
> 		type mark : verdict
> 		elements = { 0x00000100 : jump BOut_2, 0x00000080 : jump BOut_1}
> 	}
> 
> ...
> 
> 	chain BIn_1 {
> 		counter packets 133 bytes 63243 
> 	}
> 
> 	chain BOut_1 {
> 		counter packets 136 bytes 34430 
> 	}
> }
> 
> delete script:
> 
> # cat /tmp/nft-18536-delete-1.tmp  
> delete element mangle client_to_any { 0x00000080 : jump BIn_1 }
> delete element mangle any_to_client { 0x00000080 : jump BOut_1 }
> delete chain ip mangle BIn_1
> delete chain ip mangle BOut_1
> 
> Result:
> 
> # nft -f  /tmp/nft-18536-delete-1.tmp 
> /tmp/nft-18536-delete-1.tmp:3:1-29: Error: Could not process rule: Device or resource busy
> delete chain ip mangle BIn_1
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> /tmp/nft-18536-delete-1.tmp:4:1-30: Error: Could not process rule: Device or resource busy
> delete chain ip mangle BOut_1
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> 
> nft is from git://git.netfilter.org/nftables @ cba42084057b6de61d95d87177f0f8c01db539ab (HEAD)
> kernel is 4.2.0-rc6 with net-next applied from Aug 18th)
> 
> Does it make sense to update to a newer kernel (4.2-final or current net-next) or is this
> expected behavior?

The kernel should allow this.

Will be sending patches for this soon. Will you have some time to
test? If so I would be glad to add your Tested-by: tag to the patch.