nsfs: add open_namespace()

and call it from open_related_ns().

Christian Brauner committed 2 years ago

Commit 460695a1 parent 85e4daa2 files · +33 −24Browse files

Unified · Split

2 files

fs/internal.h +2 −0
fs/nsfs.c +31 −24

@@ -17,6 +17,7 @@ struct fs_context; · 16 unmodified lines
17	17	struct pipe_inode_info;
18	18	struct iov_iter;
19	19	struct mnt_idmap;
	20	+struct ns_common;
20	21
21	22	/*
22	23	* block/bdev.c
@@ -321,3 +322,4 @@ struct stashed_operations { · 298 unmodified lines
321	322	int path_from_stashed(struct dentry *stashed, struct vfsmount mnt, void *data,
322	323	struct path *path);
323	324	void stashed_dentry_prune(struct dentry *dentry);
	325	+int open_namespace(struct ns_common *ns);

fs/nsfs.c+31−24

@@ -82,40 +82,47 @@ int ns_get_path(struct path path, struct task_struct task, · 81 unmodified lines
82	82	return ns_get_path_cb(path, ns_get_path_task, &args);
83	83	}
84	84
85		−int open_related_ns(struct ns_common *ns,
86		− struct ns_common (get_ns)(struct ns_common *ns))
	85	+/**
	86	+ * open_namespace - open a namespace
	87	+ * @ns: the namespace to open
	88	+ *
	89	+ * This will consume a reference to @ns indendent of success or failure.
	90	+ *
	91	+ * Return: A file descriptor on success or a negative error code on failure.
	92	+ */
	93	+int open_namespace(struct ns_common *ns)
87	94	{
88		− struct path path = {};
89		− struct ns_common *relative;
	95	+ struct path path __free(path_put) = {};
90	96	struct file *f;
91	97	int err;
92		− int fd;
93	98
94		− fd = get_unused_fd_flags(O_CLOEXEC);
	99	+ /* call first to consume reference */
	100	+ err = path_from_stashed(&ns->stashed, nsfs_mnt, ns, &path);
	101	+ if (err < 0)
	102	+ return err;
	103	+
	104	+ CLASS(get_unused_fd, fd)(O_CLOEXEC);
95	105	if (fd < 0)
96	106	return fd;
97	107
	108	+ f = dentry_open(&path, O_RDONLY, current_cred());
	109	+ if (IS_ERR(f))
	110	+ return PTR_ERR(f);
	111	+
	112	+ fd_install(fd, f);
	113	+ return take_fd(fd);
	114	+}
	115	+
	116	+int open_related_ns(struct ns_common *ns,
	117	+ struct ns_common (get_ns)(struct ns_common *ns))
	118	+{
	119	+ struct ns_common *relative;
	120	+
98	121	relative = get_ns(ns);
99		− if (IS_ERR(relative)) {
100		− put_unused_fd(fd);
	122	+ if (IS_ERR(relative))
101	123	return PTR_ERR(relative);
102		− }
103	124
104		− err = path_from_stashed(&relative->stashed, nsfs_mnt, relative, &path);
105		− if (err < 0) {
106		− put_unused_fd(fd);
107		− return err;
108		− }
109		−
110		− f = dentry_open(&path, O_RDONLY, current_cred());
111		− path_put(&path);
112		− if (IS_ERR(f)) {
113		− put_unused_fd(fd);
114		− fd = PTR_ERR(f);
115		− } else
116		− fd_install(fd, f);
117		−
118		− return fd;
	125	+ return open_namespace(relative);
119	126	}
120	127	EXPORT_SYMBOL_GPL(open_related_ns);
121	128