[NFS]: Check that the server returns a valid regular file to our OPEN request

 Since it appears that some servers don't...

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index c9ecb8119632..3db1c9f0b09c 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -419,6 +419,22 @@ static int _nfs4_proc_open(struct inode *dir, struct nfs4_state_owner  *sp, stru
         o_arg->clientid = sp->so_client->cl_clientid;
 
         status = rpc_call_sync(server->client, &msg, RPC_TASK_NOINTR);
+        if (status == 0) {
+                /* OPEN on anything except a regular file is disallowed in NFSv4 */
+                switch (o_res->f_attr->mode & S_IFMT) {
+                        case S_IFREG:
+                                break;
+                        case S_IFLNK:
+                                status = -ELOOP;
+                                break;
+                        case S_IFDIR:
+                                status = -EISDIR;
+                                break;
+                        default:
+                                status = -ENOTDIR;
+                }
+        }
+
         nfs_increment_open_seqid(status, o_arg->seqid);
         if (status != 0)
                 goto out;