[PATCH 1/7] nfsd4: reserve space for integrity/privacy

["J. Bruce Fields" <bfields@redhat.com>]

From: "J. Bruce Fields" <bfields@redhat.com>

If a compound reply comes too close to filling up this first page, the
gss code may end up dropping it, resulting in a client hang in the
krb5i/krb5p case.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/nfsd/nfs4proc.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 9d1c5db..f45096e 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1202,7 +1202,13 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
 	resp->tagp = resp->p;
 	/* reserve space for: taglen, tag, and opcnt */
 	resp->p += 2 + XDR_QUADLEN(args->taglen);
-	resp->end = rqstp->rq_res.head[0].iov_base + PAGE_SIZE;
+	/*
+	 * In the integrity and privacy cases we need to reserve a
+	 * little extra space for a tail (see svcauth_gss_wrap_resp_priv
+	 * and svcauth_gss_wrap_resp_integ):
+	 */
+	resp->end = rqstp->rq_res.head[0].iov_base + PAGE_SIZE
+						- 2 * RPC_MAX_AUTH_SIZE;
 	resp->taglen = args->taglen;
 	resp->tag = args->tag;
 	resp->opcnt = 0;
-- 
1.7.11.7