LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Yordan Karadzhov (VMware)" <y.karadz@gmail.com>
To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: viro@zeniv.linux.org.uk, ebiederm@xmission.com,
	rostedt@goodmis.org, mingo@redhat.com, hagen@jauu.net,
	rppt@kernel.org, James.Bottomley@HansenPartnership.com,
	akpm@linux-foundation.org, vvs@virtuozzo.com,
	shakeelb@google.com, christian.brauner@ubuntu.com,
	mkoutny@suse.com,
	"Yordan Karadzhov (VMware)" <y.karadz@gmail.com>
Subject: [RFC PATCH 3/4] namespacefs: Couple namespacefs to the PID namespace
Date: Thu, 18 Nov 2021 20:12:09 +0200	[thread overview]
Message-ID: <20211118181210.281359-4-y.karadz@gmail.com> (raw)
In-Reply-To: <20211118181210.281359-1-y.karadz@gmail.com>

When the PID namespace gets initialized, a directory called 'pid' is
added to 'namespacesfs'. This directory represents the main PID namespace
and also serves as a trunk (parent) of all child PID namespaces. Every
time when a new PID namespace is created a corresponding directory is
added to 'namespacefs/pid/parent/hierarchy/'. The 'inum' of the new
namespace gives the name of its directory. When the PID namespace is
destroyed the corresponding directory is removed.

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 fs/namespacefs/inode.c | 21 +++++++++++++++++++++
 kernel/pid_namespace.c |  9 +++++++++
 2 files changed, 30 insertions(+)

diff --git a/fs/namespacefs/inode.c b/fs/namespacefs/inode.c
index 012c1c43b44d..55d71733164c 100644
--- a/fs/namespacefs/inode.c
+++ b/fs/namespacefs/inode.c
@@ -11,7 +11,9 @@
 #include <linux/fsnotify.h>
 #include <linux/magic.h>
 #include <linux/idr.h>
+#include <linux/proc_ns.h>
 #include <linux/seq_file.h>
+#include <linux/pid_namespace.h>
 
 static struct vfsmount *namespacefs_mount;
 static int namespacefs_mount_count;
@@ -307,6 +309,19 @@ void namespacefs_remove_pid_ns_dir(struct pid_namespace *ns)
 	namespacefs_remove_dir(ns->ns.dentry);
 }
 
+static int add_ns_dentry(struct ns_common *ns)
+{
+	struct dentry *dentry =
+		namespacefs_create_dir(ns->ops->name, NULL, &init_user_ns);
+
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
+	ns->dentry = dentry;
+
+	return 0;
+}
+
 #define _NS_MOUNT_DIR	"namespaces"
 
 static int __init namespacefs_init(void)
@@ -321,8 +336,14 @@ static int __init namespacefs_init(void)
 	if (err)
 		goto rm_mount;
 
+	err = add_ns_dentry(&init_pid_ns.ns);
+	if (err)
+		goto unreg;
+
 	return 0;
 
+ unreg:
+	unregister_filesystem(&namespacefs_fs_type);
  rm_mount:
 	sysfs_remove_mount_point(fs_kobj, _NS_MOUNT_DIR);
  fail:
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index a46a3723bc66..1690b2c87661 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -12,6 +12,7 @@
 #include <linux/pid.h>
 #include <linux/pid_namespace.h>
 #include <linux/user_namespace.h>
+#include <linux/namespacefs.h>
 #include <linux/syscalls.h>
 #include <linux/cred.h>
 #include <linux/err.h>
@@ -101,6 +102,7 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
 	err = ns_alloc_inum(&ns->ns);
 	if (err)
 		goto out_free_idr;
+
 	ns->ns.ops = &pidns_operations;
 
 	refcount_set(&ns->ns.count, 1);
@@ -110,8 +112,14 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
 	ns->ucounts = ucounts;
 	ns->pid_allocated = PIDNS_ADDING;
 
+	err = namespacefs_create_pid_ns_dir(ns);
+	if (err)
+		goto out_free_inum;
+
 	return ns;
 
+out_free_inum:
+	ns_free_inum(&ns->ns);
 out_free_idr:
 	idr_destroy(&ns->idr);
 	kmem_cache_free(pid_ns_cachep, ns);
@@ -133,6 +141,7 @@ static void delayed_free_pidns(struct rcu_head *p)
 
 static void destroy_pid_namespace(struct pid_namespace *ns)
 {
+	namespacefs_remove_pid_ns_dir(ns);
 	ns_free_inum(&ns->ns);
 
 	idr_destroy(&ns->idr);
-- 
2.33.1


  parent reply	other threads:[~2021-11-18 18:13 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-18 18:12 [RFC PATCH 0/4] namespacefs: Proof-of-Concept Yordan Karadzhov (VMware)
2021-11-18 18:12 ` [RFC PATCH 1/4] namespacefs: Introduce 'namespacefs' Yordan Karadzhov (VMware)
2021-11-18 18:12 ` [RFC PATCH 2/4] namespacefs: Add methods to create/remove PID namespace directories Yordan Karadzhov (VMware)
2021-11-18 18:12 ` Yordan Karadzhov (VMware) [this message]
2021-11-18 18:12 ` [RFC PATCH 4/4] namespacefs: Couple namespacefs to the UTS namespace Yordan Karadzhov (VMware)
2021-11-18 18:55 ` [RFC PATCH 0/4] namespacefs: Proof-of-Concept Eric W. Biederman
2021-11-18 19:02   ` Steven Rostedt
2021-11-18 19:22     ` Eric W. Biederman
2021-11-18 19:36       ` Steven Rostedt
2021-11-18 19:24   ` Steven Rostedt
2021-11-19  9:50     ` Kirill Tkhai
2021-11-19 12:45     ` James Bottomley
     [not found]       ` <20211119092758.1012073e@gandalf.local.home>
2021-11-19 16:42         ` James Bottomley
2021-11-19 17:14           ` Yordan Karadzhov
2021-11-19 17:22             ` Steven Rostedt
2021-11-19 23:22             ` James Bottomley
2021-11-20  0:07               ` Steven Rostedt
2021-11-20  0:14                 ` James Bottomley
     [not found]         ` <f6ca1f5bdb3b516688f291d9685a6a59f49f1393.camel@HansenPartnership.com>
2021-11-19 16:47           ` Steven Rostedt
2021-11-19 16:49             ` Steven Rostedt
2021-11-19 23:08               ` James Bottomley
2021-11-22 13:02                 ` Yordan Karadzhov
2021-11-22 13:44                   ` James Bottomley
2021-11-22 15:00                     ` Yordan Karadzhov
2021-11-22 15:47                       ` James Bottomley
2021-11-22 16:15                         ` Yordan Karadzhov
2021-11-19 14:26   ` Yordan Karadzhov
2021-11-18 21:24 ` Mike Rapoport

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20211118181210.281359-4-y.karadz@gmail.com \
    --to=y.karadz@gmail.com \
    --cc=James.Bottomley@HansenPartnership.com \
    --cc=akpm@linux-foundation.org \
    --cc=christian.brauner@ubuntu.com \
    --cc=ebiederm@xmission.com \
    --cc=hagen@jauu.net \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=mkoutny@suse.com \
    --cc=rostedt@goodmis.org \
    --cc=rppt@kernel.org \
    --cc=shakeelb@google.com \
    --cc=viro@zeniv.linux.org.uk \
    --cc=vvs@virtuozzo.com \
    --subject='Re: [RFC PATCH 3/4] namespacefs: Couple namespacefs to the PID namespace' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).