4 files changed, 22 insertions, 3 deletions

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 7f5bad0393b1..eac82830bfd7 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -177,7 +177,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp, struct nfsd3_readargs *argp,
         if (max_blocksize < resp->count)
                 resp->count = max_blocksize;
 
-        svc_reserve(rqstp, ((1 + NFS3_POST_OP_ATTR_WORDS + 3)<<2) + resp->count +4);
+        svc_reserve_auth(rqstp, ((1 + NFS3_POST_OP_ATTR_WORDS + 3)<<2) + resp->count +4);
 
         fh_copy(&resp->fh, &argp->fh);
         nfserr = nfsd_read(rqstp, &resp->fh, NULL,
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 5cc2eec981b8..b2c7147aa921 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -155,7 +155,7 @@ nfsd_proc_read(struct svc_rqst *rqstp, struct nfsd_readargs *argp,
                                 argp->count);
                 argp->count = NFSSVC_MAXBLKSIZE_V2;
         }
-        svc_reserve(rqstp, (19<<2) + argp->count + 4);
+        svc_reserve_auth(rqstp, (19<<2) + argp->count + 4);
 
         resp->count = argp->count;
         nfserr = nfsd_read(rqstp, fh_copy(&resp->fh, &argp->fh), NULL,
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 35fa4d5aadd0..4a7ae8ab6eb8 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -396,4 +396,23 @@ char *		   svc_print_addr(struct svc_rqst *, char *, size_t);
 
 #define RPC_MAX_ADDRBUFLEN      (63U)
 
+/*
+ * When we want to reduce the size of the reserved space in the response
+ * buffer, we need to take into account the size of any checksum data that
+ * may be at the end of the packet. This is difficult to determine exactly
+ * for all cases without actually generating the checksum, so we just use a
+ * static value.
+ */
+static inline void
+svc_reserve_auth(struct svc_rqst *rqstp, int space)
+{
+        int                     added_space = 0;
+
+        switch(rqstp->rq_authop->flavour) {
+                case RPC_AUTH_GSS:
+                        added_space = RPC_MAX_AUTH_SIZE;
+        }
+        return svc_reserve(rqstp, space + added_space);
+}
+
 #endif /* SUNRPC_SVC_H */
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index b7503c103ae8..e673ef993904 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -907,7 +907,7 @@ svc_process(struct svc_rqst *rqstp)
          * better idea of reply size
          */
         if (procp->pc_xdrressize)
-                svc_reserve(rqstp, procp->pc_xdrressize<<2);
+                svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
 
         /* Call the function that processes the request. */
         if (!versp->vs_dispatch) {