From: ebiederm@xmission.com (Eric W. Biederman)
To: <linux-kernel@vger.kernel.org>
Cc: Linux Containers <containers@lists.osdl.org>,
<netdev@vger.kernel.org>,
netfilter-devel@vger.kernel.org, <linux-fsdevel@vger.kernel.org>,
jamal <hadi@cyberus.ca>, Daniel Lezcano <daniel.lezcano@free.fr>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Ulrich Drepper <drepper@gmail.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
David Miller <davem@davemloft.net>,
"Serge E. Hallyn" <serge@hallyn.com>,
Pavel Emelyanov <xemul@openvz.org>,
Pavel Emelyanov <xemul@parallels.com>,
Ben Greear <greearb@candelatech.com>,
Matt Helsley <matthltc@us.ibm.com>,
Jonathan Corbet <corbet@lwn.net>,
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
Jan Engelhardt <jengelh@medozas.de>,
Patrick McHardy <kaber@trash.net>
Subject: [PATCH 6/8] ns proc: Add support for the mount namespace
Date: Thu, 23 Sep 2010 01:50:45 -0700 [thread overview]
Message-ID: <m1mxr8q1wa.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <m1ocborgq7.fsf@fess.ebiederm.org> (Eric W. Biederman's message of "Thu, 23 Sep 2010 01:45:04 -0700")
The mount namespace is a little tricky as an arbitrary
decision must be made about what to set fs->root and
fs->pwd to, as there is no expectation of a relationship
between the two mount namespaces.
Therefor I arbitrary find the root mount point, and follow
every mount on top of it to find the top of the mount stack.
Then I set fs->root and fs->pwd to that location.
The topmost root of the mount stack seems like a reasonable place to be.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
fs/namespace.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++
fs/proc/namespaces.c | 1 +
include/linux/proc_fs.h | 1 +
3 files changed, 59 insertions(+), 0 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index a72eaab..ed11bac 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -32,6 +32,7 @@
#include <linux/idr.h>
#include <linux/fs_struct.h>
#include <linux/fsnotify.h>
+#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
@@ -2418,3 +2419,59 @@ void put_mnt_ns(struct mnt_namespace *ns)
kfree(ns);
}
EXPORT_SYMBOL(put_mnt_ns);
+
+
+static void *mntns_get(struct task_struct *task)
+{
+ struct mnt_namespace *ns;
+ rcu_read_lock();
+ ns = task->nsproxy->mnt_ns;
+ get_mnt_ns(ns);
+ rcu_read_unlock();
+ return ns;
+}
+
+static void mntns_put(void *ns)
+{
+ put_mnt_ns(ns);
+}
+
+static int mntns_install(struct nsproxy *nsproxy, void *ns)
+{
+ struct fs_struct *fs = current->fs;
+ struct mnt_namespace *mnt_ns = ns;
+ struct path root;
+
+ if (fs->users != 1)
+ return -EINVAL;
+
+ get_mnt_ns(mnt_ns);
+ put_mnt_ns(nsproxy->mnt_ns);
+ nsproxy->mnt_ns = mnt_ns;
+
+ /* Find the root */
+ root.mnt = mnt_ns->root;
+ root.dentry = mnt_ns->root->mnt_root;
+ path_get(&root);
+ while(d_mountpoint(root.dentry) && follow_down(&root))
+ ;
+
+ /* Update the pwd and root */
+ path_get(&root);
+ path_get(&root);
+ path_put(&fs->root);
+ path_put(&fs->pwd);
+ fs->root = root;
+ fs->pwd = root;
+ path_put(&root);
+
+ return 0;
+}
+
+const struct proc_ns_operations mntns_operations = {
+ .name = PROC_NSNAME("mnt"),
+ .get = mntns_get,
+ .put = mntns_put,
+ .install = mntns_install,
+};
+
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 2f503b5..c5956ad 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -25,6 +25,7 @@ static const struct proc_ns_operations *ns_entries[] = {
#ifdef CONFIG_IPC_NS
&ipcns_operations,
#endif
+ &mntns_operations,
};
static const struct file_operations ns_file_operations = {
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 9a9ef31..8a260b0 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -265,6 +265,7 @@ struct proc_ns_operations {
extern const struct proc_ns_operations netns_operations;
extern const struct proc_ns_operations utsns_operations;
extern const struct proc_ns_operations ipcns_operations;
+extern const struct proc_ns_operations mntns_operations;
extern struct file *proc_ns_fget(int fd);
union proc_op {
--
1.6.5.2.143.g8cc62
next prev parent reply other threads:[~2010-09-23 8:50 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-23 8:45 [ABI REVIEW][PATCH 0/8] Namespace file descriptors Eric W. Biederman
2010-09-23 8:46 ` [PATCH 1/8] ns: proc files for namespace naming policy Eric W. Biederman
2010-09-23 8:46 ` [PATCH 2/8] ns: Introduce the setns syscall Eric W. Biederman
2010-09-23 8:47 ` [PATCH 3/8] ns proc: Add support for the network namespace Eric W. Biederman
2010-09-23 11:27 ` Louis Rilling
2010-09-23 16:00 ` Eric W. Biederman
2010-09-23 8:48 ` [PATCH 4/8] ns proc: Add support for the uts namespace Eric W. Biederman
2010-09-23 8:49 ` [PATCH 5/8] ns proc: Add support for the ipc namespace Eric W. Biederman
2010-09-23 8:50 ` Eric W. Biederman [this message]
2010-09-23 8:51 ` [PATCH 7/8] net: Allow setting the network namespace by fd Eric W. Biederman
2010-09-23 9:41 ` Eric Dumazet
2010-09-23 16:03 ` Eric W. Biederman
2010-09-23 11:22 ` jamal
2010-09-23 14:58 ` David Lamparter
2010-09-24 11:51 ` jamal
2010-09-24 12:57 ` David Lamparter
2010-09-24 13:32 ` jamal
2010-09-24 14:09 ` David Lamparter
2010-09-24 14:16 ` jamal
2010-09-23 15:14 ` Eric W. Biederman
2010-09-23 14:22 ` Brian Haley
2010-09-23 16:16 ` Eric W. Biederman
2010-09-24 13:46 ` Daniel Lezcano
2010-09-23 8:51 ` [PATCH 8/8] net: Implement socketat Eric W. Biederman
2010-09-23 8:56 ` Pavel Emelyanov
2010-09-23 11:19 ` jamal
2010-09-23 11:33 ` Pavel Emelyanov
2010-09-23 11:40 ` jamal
2010-09-23 11:53 ` Pavel Emelyanov
2010-09-23 12:11 ` jamal
2010-09-23 12:34 ` Pavel Emelyanov
2010-09-23 14:54 ` David Lamparter
2010-09-23 15:00 ` Eric W. Biederman
2010-10-02 21:13 ` Daniel Lezcano
2010-10-03 13:44 ` jamal
2010-10-04 10:13 ` Daniel Lezcano
2010-10-04 19:07 ` Eric W. Biederman
2010-10-15 12:30 ` netns patches WAS( " jamal
2010-10-26 20:52 ` jamal
2010-10-27 0:27 ` Eric W. Biederman
2010-09-23 15:18 ` [ABI REVIEW][PATCH 0/8] Namespace file descriptors David Lamparter
2010-09-23 16:32 ` Eric W. Biederman
2010-09-23 16:49 ` David Lamparter
2010-09-24 13:02 ` Andrew Lutomirski
2010-09-24 13:49 ` Daniel Lezcano
2010-09-24 17:06 ` Eric W. Biederman
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