fsnotify: put inode specific fields in an fsnotify_mark in a union

The addition of marks on vfs mounts will be simplified if the inode
specific parts of a mark and the vfsmnt specific parts of a mark are
actually in a union so naming can be easy.  This patch just implements the
inode struct and the union.

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index a48d68a..4b1587f 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -445,7 +445,7 @@
 	if (wd == -1) {
 		WARN_ONCE(1, "%s: ientry=%p ientry->wd=%d ientry->group=%p"
 			" ientry->inode=%p\n", __func__, ientry, ientry->wd,
-			ientry->fsn_entry.group, ientry->fsn_entry.inode);
+			ientry->fsn_entry.group, ientry->fsn_entry.i.inode);
 		goto out;
 	}
 
@@ -454,7 +454,7 @@
 	if (unlikely(!found_ientry)) {
 		WARN_ONCE(1, "%s: ientry=%p ientry->wd=%d ientry->group=%p"
 			" ientry->inode=%p\n", __func__, ientry, ientry->wd,
-			ientry->fsn_entry.group, ientry->fsn_entry.inode);
+			ientry->fsn_entry.group, ientry->fsn_entry.i.inode);
 		goto out;
 	}
 
@@ -468,9 +468,9 @@
 			"entry->inode=%p found_ientry=%p found_ientry->wd=%d "
 			"found_ientry->group=%p found_ientry->inode=%p\n",
 			__func__, ientry, ientry->wd, ientry->fsn_entry.group,
-			ientry->fsn_entry.inode, found_ientry, found_ientry->wd,
+			ientry->fsn_entry.i.inode, found_ientry, found_ientry->wd,
 			found_ientry->fsn_entry.group,
-			found_ientry->fsn_entry.inode);
+			found_ientry->fsn_entry.i.inode);
 		goto out;
 	}
 
@@ -482,7 +482,7 @@
 	if (unlikely(atomic_read(&ientry->fsn_entry.refcnt) < 3)) {
 		printk(KERN_ERR "%s: ientry=%p ientry->wd=%d ientry->group=%p"
 			" ientry->inode=%p\n", __func__, ientry, ientry->wd,
-			ientry->fsn_entry.group, ientry->fsn_entry.inode);
+			ientry->fsn_entry.group, ientry->fsn_entry.i.inode);
 		/* we can't really recover with bad ref cnting.. */
 		BUG();
 	}