Unverified Commit 460695a2 authored by Christian Brauner's avatar Christian Brauner
Browse files

nsfs: add open_namespace() 

and call it from open_related_ns().

Link: https://lore.kernel.org/r/20240627-work-pidfs-v1-3-7e9ab6cc3bb1@kernel.org


Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarAlexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 85e4daae

fs/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ struct fs_context; 
struct pipe_inode_info;

struct iov_iter;

struct mnt_idmap;

struct ns_common;



/*

 * block/bdev.c
@@ -321,3 +322,4 @@ struct stashed_operations { 
int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,

		      struct path *path);

void stashed_dentry_prune(struct dentry *dentry);

int open_namespace(struct ns_common *ns);

fs/nsfs.c

+31 −24
Original line number Diff line number Diff line
@@ -82,40 +82,47 @@ int ns_get_path(struct path *path, struct task_struct *task, 
	return ns_get_path_cb(path, ns_get_path_task, &args);

}



int open_related_ns(struct ns_common *ns,

		   struct ns_common *(*get_ns)(struct ns_common *ns))

/**

 * open_namespace - open a namespace

 * @ns: the namespace to open

 *

 * This will consume a reference to @ns indendent of success or failure.

 *

 * Return: A file descriptor on success or a negative error code on failure.

 */

int open_namespace(struct ns_common *ns)

{

	struct path path = {};

	struct ns_common *relative;

	struct path path __free(path_put) = {};

	struct file *f;

	int err;

	int fd;



	fd = get_unused_fd_flags(O_CLOEXEC);

	/* call first to consume reference */

	err = path_from_stashed(&ns->stashed, nsfs_mnt, ns, &path);

	if (err < 0)

		return err;



	CLASS(get_unused_fd, fd)(O_CLOEXEC);

	if (fd < 0)

		return fd;



	relative = get_ns(ns);

	if (IS_ERR(relative)) {

		put_unused_fd(fd);

		return PTR_ERR(relative);

	}

	f = dentry_open(&path, O_RDONLY, current_cred());

	if (IS_ERR(f))

		return PTR_ERR(f);



	err = path_from_stashed(&relative->stashed, nsfs_mnt, relative, &path);

	if (err < 0) {

		put_unused_fd(fd);

		return err;

	fd_install(fd, f);

	return take_fd(fd);

}



	f = dentry_open(&path, O_RDONLY, current_cred());

	path_put(&path);

	if (IS_ERR(f)) {

		put_unused_fd(fd);

		fd = PTR_ERR(f);

	} else

		fd_install(fd, f);

int open_related_ns(struct ns_common *ns,

		   struct ns_common *(*get_ns)(struct ns_common *ns))

{

	struct ns_common *relative;



	return fd;

	relative = get_ns(ns);

	if (IS_ERR(relative))

		return PTR_ERR(relative);



	return open_namespace(relative);

}

EXPORT_SYMBOL_GPL(open_related_ns);