Unverified Commit ad4a3599 authored by Christian Brauner's avatar Christian Brauner
Browse files

mount: simplify __do_loopback() 

Remove the OPEN_TREE_NAMESPACE flag checking from __do_loopback() and
instead have callers pass CL_COPY_MNT_NS_FILE directly in copy_flags.

Link: https://patch.msgid.link/20260122-work-fsmount-namespace-v1-2-5ef0a886e646@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 0c0b0463

fs/namespace.c

+9 −22
Original line number Diff line number Diff line
@@ -2958,10 +2958,9 @@ static inline bool may_copy_tree(const struct path *path) 
}



static struct mount *__do_loopback(const struct path *old_path,

				   unsigned int flags, unsigned int copy_flags)

				   bool recurse, unsigned int copy_flags)

{

	struct mount *old = real_mount(old_path->mnt);

	bool recurse = flags & AT_RECURSIVE;



	if (IS_MNT_UNBINDABLE(old))

		return ERR_PTR(-EINVAL);
@@ -2972,18 +2971,6 @@ static struct mount *__do_loopback(const struct path *old_path, 
	if (!recurse && __has_locked_children(old, old_path->dentry))

		return ERR_PTR(-EINVAL);



	/*

	 * When creating a new mount namespace we don't want to copy over

	 * mounts of mount namespaces to avoid the risk of cycles and also to

	 * minimize the default complex interdependencies between mount

	 * namespaces.

	 *

	 * We could ofc just check whether all mount namespace files aren't

	 * creating cycles but really let's keep this simple.

	 */

	if (!(flags & OPEN_TREE_NAMESPACE))

		copy_flags |= CL_COPY_MNT_NS_FILE;



	if (recurse)

		return copy_tree(old, old_path->dentry, copy_flags);
@@ -2998,7 +2985,6 @@ static int do_loopback(const struct path *path, const char *old_name, 
{

	struct path old_path __free(path_put) = {};

	struct mount *mnt = NULL;

	unsigned int flags = recurse ? AT_RECURSIVE : 0;

	int err;



	if (!old_name || !*old_name)
@@ -3017,7 +3003,7 @@ static int do_loopback(const struct path *path, const char *old_name, 
	if (!check_mnt(mp.parent))

		return -EINVAL;



	mnt = __do_loopback(&old_path, flags, 0);

	mnt = __do_loopback(&old_path, recurse, CL_COPY_MNT_NS_FILE);

	if (IS_ERR(mnt))

		return PTR_ERR(mnt);
@@ -3055,7 +3041,7 @@ static struct mnt_namespace *get_detached_copy(const struct path *path, unsigned 
			ns->seq_origin = src_mnt_ns->ns.ns_id;

	}



	mnt = __do_loopback(path, flags, 0);

	mnt = __do_loopback(path, (flags & AT_RECURSIVE), CL_COPY_MNT_NS_FILE);

	if (IS_ERR(mnt)) {

		emptied_ns = ns;

		return ERR_CAST(mnt);
@@ -3087,7 +3073,8 @@ static struct file *open_detached_copy(struct path *path, unsigned int flags) 
	return file;

}



static struct mnt_namespace *create_new_namespace(struct path *path, unsigned int flags)

static struct mnt_namespace *create_new_namespace(struct path *path,

						  bool recurse)

{

	struct mnt_namespace *ns = current->nsproxy->mnt_ns;

	struct user_namespace *user_ns = current_user_ns();
@@ -3135,7 +3122,7 @@ static struct mnt_namespace *create_new_namespace(struct path *path, unsigned in 
	 * to the restrictions of creating detached bind-mounts. It

	 * has a lot saner and simpler semantics.

	 */

	mnt = __do_loopback(path, flags, copy_flags);

	mnt = __do_loopback(path, recurse, copy_flags);

	scoped_guard(mount_writer) {

		if (IS_ERR(mnt)) {

			emptied_ns = new_ns;
@@ -3164,11 +3151,11 @@ static struct mnt_namespace *create_new_namespace(struct path *path, unsigned in 
	return new_ns;

}



static struct file *open_new_namespace(struct path *path, unsigned int flags)

static struct file *open_new_namespace(struct path *path, bool recurse)

{

	struct mnt_namespace *new_ns;



	new_ns = create_new_namespace(path, flags);

	new_ns = create_new_namespace(path, recurse);

	if (IS_ERR(new_ns))

		return ERR_CAST(new_ns);

	return open_namespace_file(to_ns_common(new_ns));
@@ -3217,7 +3204,7 @@ static struct file *vfs_open_tree(int dfd, const char __user *filename, unsigned 
		return ERR_PTR(ret);



	if (flags & OPEN_TREE_NAMESPACE)

		return open_new_namespace(&path, flags);

		return open_new_namespace(&path, (flags & AT_RECURSIVE));



	if (flags & OPEN_TREE_CLONE)

		return open_detached_copy(&path, flags);