init: add an init_chown helper

Add a simple helper to chown with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

3 files changed, 20 insertions, 2 deletions

diff --git a/fs/init.c b/fs/init.c
index 2c78f24814dd..edd024465595 100644
--- a/fs/init.c
+++ b/fs/init.c
@@ -78,6 +78,24 @@ dput_and_out:
 	return error;
 }
 
+int __init init_chown(const char *filename, uid_t user, gid_t group, int flags)
+{
+	int lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+	struct path path;
+	int error;
+
+	error = kern_path(filename, lookup_flags, &path);
+	if (error)
+		return error;
+	error = mnt_want_write(path.mnt);
+	if (!error) {
+		error = chown_common(&path, user, group);
+		mnt_drop_write(path.mnt);
+	}
+	path_put(&path);
+	return error;
+}
+
 int __init init_unlink(const char *pathname)
 {
 	return do_unlinkat(AT_FDCWD, getname_kernel(pathname));
diff --git a/fs/internal.h b/fs/internal.h
index 491d1e63809b..e81b9e23c3ea 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -134,7 +134,7 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
 		int flag);
-
+int chown_common(const struct path *path, uid_t user, gid_t group);
 extern int vfs_open(const struct path *, struct file *);
 
 /*
diff --git a/fs/open.c b/fs/open.c
index f62f4752bb43..49960a1248f1 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -639,7 +639,7 @@ SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
 	return do_fchmodat(AT_FDCWD, filename, mode);
 }
 
-static int chown_common(const struct path *path, uid_t user, gid_t group)
+int chown_common(const struct path *path, uid_t user, gid_t group)
 {
 	struct inode *inode = path->dentry->d_inode;
 	struct inode *delegated_inode = NULL;