Unverified Commit 901766df authored by Christian Brauner's avatar Christian Brauner
Browse files

fs: add vfs_open_tree() helper 

Split out vfs_open_tree() from open_tree() so we can use it in later
patches.

Link: https://lore.kernel.org/r/20250128-work-mnt_idmap-update-v2-v1-1-c25feb0d2eb3@kernel.org


Reviewed-by: default avatar"Seth Forshee (DigitalOcean)" <sforshee@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 8f6116b5

fs/namespace.c

+26 −23
Original line number Diff line number Diff line
@@ -3002,24 +3002,22 @@ static struct file *open_detached_copy(struct path *path, bool recursive) 
	return file;

}



SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, flags)

static struct file *vfs_open_tree(int dfd, const char __user *filename, unsigned int flags)

{

	struct file *file;

	struct path path;

	int ret;

	struct path path __free(path_put) = {};

	int lookup_flags = LOOKUP_AUTOMOUNT | LOOKUP_FOLLOW;

	bool detached = flags & OPEN_TREE_CLONE;

	int error;

	int fd;



	BUILD_BUG_ON(OPEN_TREE_CLOEXEC != O_CLOEXEC);



	if (flags & ~(AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_RECURSIVE |

		      AT_SYMLINK_NOFOLLOW | OPEN_TREE_CLONE |

		      OPEN_TREE_CLOEXEC))

		return -EINVAL;

		return ERR_PTR(-EINVAL);



	if ((flags & (AT_RECURSIVE | OPEN_TREE_CLONE)) == AT_RECURSIVE)

		return -EINVAL;

		return ERR_PTR(-EINVAL);



	if (flags & AT_NO_AUTOMOUNT)

		lookup_flags &= ~LOOKUP_AUTOMOUNT;
@@ -3029,27 +3027,32 @@ SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, fl 
		lookup_flags |= LOOKUP_EMPTY;



	if (detached && !may_mount())

		return -EPERM;

		return ERR_PTR(-EPERM);



	fd = get_unused_fd_flags(flags & O_CLOEXEC);

	if (fd < 0)

		return fd;

	ret = user_path_at(dfd, filename, lookup_flags, &path);

	if (unlikely(ret))

		return ERR_PTR(ret);



	error = user_path_at(dfd, filename, lookup_flags, &path);

	if (unlikely(error)) {

		file = ERR_PTR(error);

	} else {

	if (detached)

			file = open_detached_copy(&path, flags & AT_RECURSIVE);

		else

			file = dentry_open(&path, O_PATH, current_cred());

		path_put(&path);

		return open_detached_copy(&path, flags & AT_RECURSIVE);



	return dentry_open(&path, O_PATH, current_cred());

}

	if (IS_ERR(file)) {

		put_unused_fd(fd);



SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, flags)

{

	int fd;

	struct file *file __free(fput) = NULL;



	file = vfs_open_tree(dfd, filename, flags);

	if (IS_ERR(file))

		return PTR_ERR(file);

	}

	fd_install(fd, file);



	fd = get_unused_fd_flags(flags & O_CLOEXEC);

	if (fd < 0)

		return fd;



	fd_install(fd, no_free_ptr(file));

	return fd;

}