[NFS]: Check that the server returns a valid regular file to our OPEN request
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 dir.c      |    4 +++-
 nfs4proc.c |   14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

Index: linux-2.6.13-rc1/fs/nfs/nfs4proc.c
===================================================================
--- linux-2.6.13-rc1.orig/fs/nfs/nfs4proc.c
+++ linux-2.6.13-rc1/fs/nfs/nfs4proc.c
@@ -671,6 +671,20 @@ static int _nfs4_do_open(struct inode *d
 	status = _nfs4_proc_open(dir, sp, &o_arg, &o_res);
 	if (status != 0)
 		goto out_err;
+	/* OPEN on anything except a regular file is disallowed in NFSv4 */
+	switch (f_attr.mode & S_IFMT) {
+		case S_IFREG:
+			break;
+		case S_IFLNK:
+			status = -ELOOP;
+			goto out_err;
+		case S_IFDIR:
+			status = -EISDIR;
+			goto out_err;
+		default:
+			status = -ENOTDIR;
+			goto out_err;
+	}
 
 	status = -ENOMEM;
 	inode = nfs_fhget(dir->i_sb, &o_res.fh, &f_attr);
Index: linux-2.6.13-rc1/fs/nfs/dir.c
===================================================================
--- linux-2.6.13-rc1.orig/fs/nfs/dir.c
+++ linux-2.6.13-rc1/fs/nfs/dir.c
@@ -954,10 +954,12 @@ static struct dentry *nfs_atomic_lookup(
 				res = NULL;
 				goto out;
 			/* This turned out not to be a regular file */
+			case -EISDIR:
+			case -ENOTDIR:
+				goto no_open;
 			case -ELOOP:
 				if (!(nd->intent.open.flags & O_NOFOLLOW))
 					goto no_open;
-			/* case -EISDIR: */
 			/* case -EINVAL: */
 			default:
 				goto out;