[CIFS] Fix oops in cifs_create when nfsd server exports cifs mount

nfsd is passing null nameidata (probably the only one doing that)
on call to create - cifs was missing one check for this.

Note that running nfsd over a cifs mount requires specifying fsid on
the nfs exports entry and requires mounting cifs with serverino mount
option.

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/cifs/export.c b/fs/cifs/export.c
index 5a08effda0a..6e66bc19f0a 100644
--- a/fs/cifs/export.c
+++ b/fs/cifs/export.c
@@ -26,15 +26,30 @@
  /*
   * See Documentation/filesystems/Exporting
   * and examples in fs/exportfs
+  *
+  * Since cifs is a network file system, an "fsid" must be included for
+  * any nfs exports file entries which refer to cifs paths.  In addition
+  * the cifs mount must be mounted with the "serverino" option (ie use stable
+  * server inode numbers instead of locally generated temporary ones).
+  * Although cifs inodes do not use generation numbers (have generation number
+  * of zero) - the inode number alone should be good enough for simple cases
+  * in which users want to export cifs shares with NFS. The decode and encode
+  * could be improved by using a new routine which expects 64 bit inode numbers
+  * instead of the default 32 bit routines in fs/exportfs
+  *
   */
 
 #include <linux/fs.h>
+#include "cifsglob.h"
+#include "cifs_debug.h"
+
  
 #ifdef CONFIG_CIFS_EXPERIMENTAL
  
 static struct dentry *cifs_get_parent(struct dentry *dentry)
 {
 	/* BB need to add code here eventually to enable export via NFSD */
+	cFYI(1, ("get parent for %p", dentry));
 	return ERR_PTR(-EACCES);
 }