nfsd4: fix unlikely race in session replay case
In the replay case, the
renew_client(session->se_client);
happens after we've droppped the sessionid_lock, and without holding a
reference on the session; so there's nothing preventing the session
being freed before we get here.
Thanks to Benny Halevy for catching a bug in an earlier version of this
patch.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Benny Halevy <bhalevy@panasas.com>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index fb27b1d..05bc5bd 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3306,10 +3306,12 @@
iov = &rqstp->rq_res.head[0];
iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base;
BUG_ON(iov->iov_len > PAGE_SIZE);
- if (nfsd4_has_session(cs) && cs->status != nfserr_replay_cache) {
- nfsd4_store_cache_entry(resp);
- dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__);
- resp->cstate.slot->sl_inuse = false;
+ if (nfsd4_has_session(cs)) {
+ if (cs->status != nfserr_replay_cache) {
+ nfsd4_store_cache_entry(resp);
+ dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__);
+ resp->cstate.slot->sl_inuse = false;
+ }
nfsd4_put_session(resp->cstate.session);
}
return 1;