nfs41: Verify channel's attributes accordingly to RFC v2

 ca_maxoperations:

      For the backchannel, the server MUST
      NOT change the value the client offers.  For the fore channel,
      the server MAY change the requested value.

  ca_maxrequests:

       For the backchannel, the server MUST NOT change the
       value the client offers.  For the fore channel, the server MAY
       change the requested value.

Signed-off-by: Vitaliy Gusev <gusev.vitaliy@nexenta.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 0b3316541734..87c584dd88b1 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5287,6 +5287,8 @@ static int nfs4_verify_fore_channel_attrs(struct nfs41_create_session_args *args
                 return -EINVAL;
         if (rcvd->max_reqs == 0)
                 return -EINVAL;
+        if (rcvd->max_reqs > NFS4_MAX_SLOT_TABLE)
+                rcvd->max_reqs = NFS4_MAX_SLOT_TABLE;
         return 0;
 }
 
@@ -5302,9 +5304,9 @@ static int nfs4_verify_back_channel_attrs(struct nfs41_create_session_args *args
         if (rcvd->max_resp_sz_cached > sent->max_resp_sz_cached)
                 return -EINVAL;
         /* These would render the backchannel useless: */
-        if (rcvd->max_ops  == 0)
+        if (rcvd->max_ops != sent->max_ops)
                 return -EINVAL;
-        if (rcvd->max_reqs == 0)
+        if (rcvd->max_reqs != sent->max_reqs)
                 return -EINVAL;
         return 0;
 }