This patch tries to address the following failure:
nfsdctl threads 0
nfsdctl listener +rdma::20049
nfsdctl listener +tcp::2049
nfsdctl listener -tcp::2049
nfsdctl: Error: Cannot assign requested address
The reason for the failure is due to the fact that socket cleanup only
happens in __svc_rdma_free() which is a deferred work triggers when an
rdma transport is destroyed. To remove a listener nfsdctl is forced to
first remove all transports via svc_xprt_destroy_all() and then re-add
the ones that are left. Due to the fact that there isn't a way to
delete a particular entry from a list where permanent sockets are
stored. Going back to the deferred work done in __svc_rdma_free(), the
work might not get to run before nfsd_nl_listener_set_doit() creates
the new transports. As a result, it finds that something is still
listening of the rdma port and rdma_bind_addr() fails.
Proposed solution is to add a delay after svc_xprt_destroy_all() to
allow for the deferred work to run.
--- Is the chosen value of 1s enough to ensure socket goes away?
I can't guarantee that.
--- Alternatives that i can think of:
(1) to go back to listener removal approach that added removal of
entry to the llist api. That would not require a removal of all
transport causing this problem to occur. Earlier it was preferred
not to change llist api.
(2) some method of checking that all deferred work occuring in
svc_xprt_destroy_all() completed.
Fixes: d093c90892607 ("nfsd: fix management of listener transports")
Signed-off-by: Olga Kornievskaia <okorniev@xxxxxxxxxx>
---
fs/nfsd/nfsctl.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index dd3267b4c203..f9f5670abcc3 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1998,8 +1998,10 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
* Since we can't delete an arbitrary llist entry, destroy the
* remaining listeners and recreate the list.
*/
- if (delete)
+ if (delete) {
svc_xprt_destroy_all(serv, net, false);
+ ssleep(1);
+ }
/* walk list of addrs again, open any that still don't exist */
nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
--
2.47.1
