nfsd4: fix encoding of out-of-space replies

If nfsd4_check_resp_size() returns an error then we should really be
truncating the reply here, otherwise we may leave extra garbage at the
end of the rpc reply.

Also add a warning to catch any cases where our reply-size estimates may
be wrong in the case of a non-idempotent operation.

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

1 files changed, 9 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 747d6a87a47d..bf8cddfdd3be 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1171,9 +1171,7 @@ struct nfsd4_operation {
 
 static struct nfsd4_operation nfsd4_ops[];
 
-#ifdef NFSD_DEBUG
 static const char *nfsd4_op_name(unsigned opnum);
-#endif
 
 /*
  * Enforce NFSv4.1 COMPOUND ordering rules:
@@ -1859,14 +1857,21 @@ static struct nfsd4_operation nfsd4_ops[] = {
         },
 };
 
-#ifdef NFSD_DEBUG
+void warn_on_nonidempotent_op(struct nfsd4_op *op)
+{
+        if (OPDESC(op)->op_flags & OP_MODIFIES_SOMETHING) {
+                pr_err("unable to encode reply to nonidempotent op %d (%s)\n",
+                        op->opnum, nfsd4_op_name(op->opnum));
+                WARN_ON_ONCE(1);
+        }
+}
+
 static const char *nfsd4_op_name(unsigned opnum)
 {
         if (opnum < ARRAY_SIZE(nfsd4_ops))
                 return nfsd4_ops[opnum].op_name;
         return "unknown_operation";
 }
-#endif
 
 #define nfsd4_voidres                   nfsd4_voidargs
 struct nfsd4_voidargs { int dummy; };