[PATCH 38/39] union-mount: Implement union-aware setxattr()

[Valerie Aurora <vaurora@redhat.com>]

---
 fs/xattr.c |   33 +++++++++++++++++++++++++++------
 1 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 46f87e8..f930ab7 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/fsnotify.h>
 #include <linux/audit.h>
+#include <linux/union.h>
 #include <asm/uaccess.h>
 
 
@@ -281,17 +282,37 @@ SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
 		size_t, size, int, flags)
 {
 	struct path path;
+	struct nameidata nd;
+	struct vfsmount *mnt;
+	char *tmp;
 	int error;
 
-	error = user_path(pathname, &path);
+	error = user_path_nd(AT_FDCWD, pathname, LOOKUP_FOLLOW, &nd, &path,
+			     &tmp);
 	if (error)
 		return error;
-	error = mnt_want_write(path.mnt);
-	if (!error) {
-		error = setxattr(path.dentry, name, value, size, flags);
-		mnt_drop_write(path.mnt);
-	}
+
+	if (IS_UNIONED_DIR(&nd.path))
+		mnt = nd.path.mnt;
+	else
+		mnt = path.mnt;
+
+	error = mnt_want_write(mnt);
+	if (error)
+		goto out;
+
+	error = union_copyup(&nd, &path);
+	if (error)
+		goto out_drop_write;
+
+	error = setxattr(path.dentry, name, value, size, flags);
+
+out_drop_write:
+	mnt_drop_write(mnt);
+out:
 	path_put(&path);
+	path_put(&nd.path);
+	putname(tmp);
 	return error;
 }
 
-- 
1.6.3.3