[Devel] [PATCH RHEL7 COMMIT] ms/netfilter: nf_tables: fix update chain error

[Vasily Averin]

The commit is pushed to "branch-rh7-3.10.0-1160.11.1.vz7.172.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.11.1.vz7.172.12
------>
commit 9f3bb479b8b5496f1fd238b1d0e3e4bd863cd8e7
Author: JingPiao Chen <chenjingpiao at gmail.com>
Date:   Fri Feb 5 14:27:17 2021 +0300

    ms/netfilter: nf_tables: fix update chain error
    
     # nft add table filter
     # nft add chain filter c1
     # nft rename chain filter c1 c2
    
    Error: Could not process rule: No such file or directory
    rename chain filter c1 c2
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
    
     # nft add chain filter c2
     # nft rename chain filter c1 c2
     # nft list table filter
    
    table ip filter {
    	chain c2 {
    	}
    
    	chain c2 {
    	}
    }
    
    Fixes: 664b0f8cd8 ("netfilter: nf_tables: add generation mask to chains")
    Signed-off-by: JingPiao Chen <chenjingpiao at gmail.com>
    Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
    (cherry picked from commit 0d18779be13766b33c69cbc26df38383598da373)
    https://bugs.openvz.org/browse/OVZ-7223
    Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
---
 net/netfilter/nf_tables_api.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 1cea127..d6dff4a 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1369,8 +1369,8 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk,
 			chain2 = nf_tables_chain_lookup(table,
 							nla[NFTA_CHAIN_NAME],
 							genmask);
-			if (IS_ERR(chain2))
-				return PTR_ERR(chain2);
+			if (!IS_ERR(chain2))
+				return -EEXIST;
 		}
 
 		if (nla[NFTA_CHAIN_COUNTERS]) {