[PATCH 37/38] union-mount: Implement union-aware setxattr()

From: Valerie Aurora
Date: Tue Jun 15 2010 - 14:48:10 EST


---
fs/xattr.c | 34 +++++++++++++++++++++++++++-------
1 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 46f87e8..66bb5c7 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -19,7 +19,7 @@
#include <linux/fsnotify.h>
#include <linux/audit.h>
#include <asm/uaccess.h>
-
+#include "union.h"

/*
* Check permissions for extended attribute access. This is a bit complicated
@@ -281,17 +281,37 @@ 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_DIR_UNIONED(nd.path.dentry))
+ 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

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