[RFC PATCH 1/3] fs: Add documentation to some `struct fs_struct` fields

[John Ericson <John.Ericson@Obsidian.Systems>]

From: John Ericson <mail@JohnEricson.me>

This will be expanded upon in the next commit.

Link: https://lore.kernel.org/all/a49ce818-f38d-41b0-bbf7-80b8aad998b1@app.fastmail.com/
Signed-off-by: John Ericson <mail@JohnEricson.me>
---
 include/linux/fs_struct.h | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h
index 0070764b790a..b5db5de9eb01 100644
--- a/include/linux/fs_struct.h
+++ b/include/linux/fs_struct.h
@@ -12,7 +12,21 @@ struct fs_struct {
 	seqlock_t seq;
 	int umask;
 	int in_exec;
-	struct path root, pwd;
+
+	/*
+	 * The root directory for the task(s) that points to this
+	 * `fs_struct`. The root directory also controls how `..`
+	 * resolve; path traversal is not allowed to resolve upwards
+	 * beyond the root directory. (It is for this latter reason that
+	 * `chroot` is a privileged operation.)
+	 */
+	struct path root;
+
+	/*
+	 * The current working directory for the task(s) that points to
+	 * this `fs_struct`.
+	 */
+	struct path pwd;
 } __randomize_layout;
 
 extern struct kmem_cache *fs_cachep;
-- 
2.51.2