fs/9p: Move writeback fid to v9fs_inode

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index ce59d15..71cab8e 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -122,6 +122,7 @@
 	struct fscache_cookie *fscache;
 	struct p9_qid *fscache_key;
 #endif
+	struct p9_fid *writeback_fid;
 	struct inode vfs_inode;
 };