nfsd4: remove redundant encode buffer size checking

Now that all op encoders can handle running out of space, we no longer
need to check the remaining size for every operation; only nonidempotent
operations need that check, and that can be done by
nfsd4_check_resp_size.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 13 insertions, 9 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 89c65a3e09e4..df643e0fb6b3 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3753,20 +3753,24 @@ static nfsd4_enc nfsd4_enc_ops[] = {
 __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 pad)
 {
         struct xdr_buf *buf = &resp->rqstp->rq_res;
-        struct nfsd4_session *session = NULL;
+        struct nfsd4_session *session = resp->cstate.session;
         struct nfsd4_slot *slot = resp->cstate.slot;
+        int slack_bytes = (char *)resp->xdr.end - (char *)resp->xdr.p;
 
-        if (!nfsd4_has_session(&resp->cstate))
-                return 0;
+        if (nfsd4_has_session(&resp->cstate)) {
 
-        session = resp->cstate.session;
+                if (buf->len + pad > session->se_fchannel.maxresp_sz)
+                        return nfserr_rep_too_big;
 
-        if (buf->len + pad > session->se_fchannel.maxresp_sz)
-                return nfserr_rep_too_big;
+                if ((slot->sl_flags & NFSD4_SLOT_CACHETHIS) &&
+                    buf->len + pad > session->se_fchannel.maxresp_cached)
+                        return nfserr_rep_too_big_to_cache;
+        }
 
-        if ((slot->sl_flags & NFSD4_SLOT_CACHETHIS) &&
-            buf->len + pad > session->se_fchannel.maxresp_cached)
-                return nfserr_rep_too_big_to_cache;
+        if (pad > slack_bytes) {
+                WARN_ON_ONCE(nfsd4_has_session(&resp->cstate));
+                return nfserr_resource;
+        }
 
         return 0;
 }