[RFC][PATCH 2/5] mqueue namespace: add unshare support

[RFC][PATCH 2/5] mqueue namespace: add unshare support

[Dave Hansen]

From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>

This patch includes the mqueue namespace in the nsproxy object. It  
also adds the support of unshare() and clone() with a new clone flag. 

It's totally harmless for the moment because the current code still 
uses the default mqueue namespace object 'init_mq_ns' 

Changes since v6 Mar 05, 2008: 

	* dropped new clone flag CLONE_NEWMQ and used CLONE_NEWIPC 
	  instead

Changes since v5 Feb 28, 2008: 

	* fix typo in create_new_namespaces()

Changes since v4: 

	* remove CLONE_NEWNS enforcement. stalled user mounts are 
	  handled in the fs ops.

Signed-off-by: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
---

 linux-2.6.git-dave/include/linux/init_task.h    |    2 +
 linux-2.6.git-dave/include/linux/mq_namespace.h |    1 
 linux-2.6.git-dave/include/linux/nsproxy.h      |    2 +
 linux-2.6.git-dave/ipc/mq_namespace.c           |   36 +++++++++++++++++++++++-
 linux-2.6.git-dave/kernel/nsproxy.c             |   11 +++++++
 5 files changed, 51 insertions(+), 1 deletion(-)

diff -puN include/linux/init_task.h~mq_namespace-add-mq_namespace-to-nsproxy include/linux/init_task.h
--- linux-2.6.git/include/linux/init_task.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/include/linux/init_task.h	2008-06-24 12:03:17.000000000 -0700
@@ -10,6 +10,7 @@
 #include <linux/user_namespace.h>
 #include <linux/securebits.h>
 #include <net/net_namespace.h>
+#include <linux/mq_namespace.h>
 
 extern struct files_struct init_files;
 
@@ -58,6 +59,7 @@ extern struct nsproxy init_nsproxy;
 	INIT_NET_NS(net_ns)                                             \
 	INIT_IPC_NS(ipc_ns)						\
 	.user_ns	= &init_user_ns,				\
+	INIT_MQ_NS(mq_ns)						\
 }
 
 #define INIT_SIGHAND(sighand) {						\
diff -puN include/linux/mq_namespace.h~mq_namespace-add-mq_namespace-to-nsproxy include/linux/mq_namespace.h
--- linux-2.6.git/include/linux/mq_namespace.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/include/linux/mq_namespace.h	2008-06-24 12:03:17.000000000 -0700
@@ -2,6 +2,7 @@
 #define _LINUX_MQ_NAMESPACE_H
 
 #include <linux/kref.h>
+#include <linux/err.h>
 
 struct vfsmount;
 
diff -puN include/linux/nsproxy.h~mq_namespace-add-mq_namespace-to-nsproxy include/linux/nsproxy.h
--- linux-2.6.git/include/linux/nsproxy.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/include/linux/nsproxy.h	2008-06-24 12:03:17.000000000 -0700
@@ -8,6 +8,7 @@ struct mnt_namespace;
 struct uts_namespace;
 struct ipc_namespace;
 struct pid_namespace;
+struct mq_namespace;
 
 /*
  * A structure to contain pointers to all per-process
@@ -29,6 +30,7 @@ struct nsproxy {
 	struct pid_namespace *pid_ns;
 	struct user_namespace *user_ns;
 	struct net 	     *net_ns;
+	struct mq_namespace *mq_ns;
 };
 extern struct nsproxy init_nsproxy;
 
diff -puN ipc/mq_namespace.c~mq_namespace-add-mq_namespace-to-nsproxy ipc/mq_namespace.c
--- linux-2.6.git/ipc/mq_namespace.c~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/ipc/mq_namespace.c	2008-06-24 12:03:17.000000000 -0700
@@ -10,14 +10,48 @@
  */
 
 #include <linux/mq_namespace.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+
+static struct mq_namespace *clone_mq_ns(struct mq_namespace *old_ns)
+{
+	struct mq_namespace *mq_ns;
+
+	mq_ns = kmalloc(sizeof(struct mq_namespace), GFP_KERNEL);
+	if (!mq_ns)
+		return ERR_PTR(-ENOMEM);
+
+	kref_init(&mq_ns->kref);
+	mq_ns->queues_count	= 0;
+	mq_ns->queues_max	= DFLT_QUEUESMAX;
+	mq_ns->msg_max		= DFLT_MSGMAX;
+	mq_ns->msgsize_max	= DFLT_MSGSIZEMAX;
+	mq_ns->mnt		= NULL;
+	return mq_ns;
+}
 
 struct mq_namespace *copy_mq_ns(unsigned long clone_flags,
 				struct mq_namespace *old_ns)
 {
+	struct mq_namespace *mq_ns;
+
 	BUG_ON(!old_ns);
-	return get_mq_ns(old_ns);
+	get_mq_ns(old_ns);
+
+	if (!(clone_flags & CLONE_NEWIPC))
+		return old_ns;
+
+	mq_ns = clone_mq_ns(old_ns);
+
+	put_mq_ns(old_ns);
+	return mq_ns;
 }
 
 void free_mq_ns(struct kref *kref)
 {
+	struct mq_namespace *ns;
+
+	ns = container_of(kref, struct mq_namespace, kref);
+	kfree(ns);
 }
diff -puN kernel/nsproxy.c~mq_namespace-add-mq_namespace-to-nsproxy kernel/nsproxy.c
--- linux-2.6.git/kernel/nsproxy.c~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/kernel/nsproxy.c	2008-06-24 12:03:17.000000000 -0700
@@ -93,8 +93,17 @@ static struct nsproxy *create_new_namesp
 		goto out_net;
 	}
 
+	new_nsp->mq_ns = copy_mq_ns(flags, tsk->nsproxy->mq_ns);
+	if (IS_ERR(new_nsp->mq_ns)) {
+		err = PTR_ERR(new_nsp->mq_ns);
+		goto out_mq;
+	}
+
 	return new_nsp;
 
+out_mq:
+	if (new_nsp->net_ns)
+		put_net(new_nsp->net_ns);
 out_net:
 	if (new_nsp->user_ns)
 		put_user_ns(new_nsp->user_ns);
@@ -182,6 +191,8 @@ void free_nsproxy(struct nsproxy *ns)
 		put_pid_ns(ns->pid_ns);
 	if (ns->user_ns)
 		put_user_ns(ns->user_ns);
+	if (ns->mq_ns)
+		put_mq_ns(ns->mq_ns);
 	put_net(ns->net_ns);
 	kmem_cache_free(nsproxy_cachep, ns);
 }
_

[RFC][PATCH 1/5] mqueue namespace: add struct mq_namespace

[Dave Hansen]

From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>

This patch adds a struct mq_namespace holding the common attributes 
of the mqueue namespace. 

The current code is modified to use the default mqueue namespace 
object 'init_mq_ns' and to prepare the ground for futur dynamic 
objects.

A new option CONFIG_MQ_NS protects configuration not using namespaces.

Signed-off-by: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
---

 linux-2.6.git-dave/include/linux/mq_namespace.h |   67 ++++++++++++++
 linux-2.6.git-dave/init/Kconfig                 |    9 +
 linux-2.6.git-dave/ipc/Makefile                 |    1 
 linux-2.6.git-dave/ipc/mq_namespace.c           |   23 +++++
 linux-2.6.git-dave/ipc/mqueue.c                 |  109 ++++++++++++------------
 5 files changed, 158 insertions(+), 51 deletions(-)

diff -puN /dev/null include/linux/mq_namespace.h
--- /dev/null	2007-04-11 11:48:27.000000000 -0700
+++ linux-2.6.git-dave/include/linux/mq_namespace.h	2008-06-24 12:03:16.000000000 -0700
@@ -0,0 +1,67 @@
+#ifndef _LINUX_MQ_NAMESPACE_H
+#define _LINUX_MQ_NAMESPACE_H
+
+#include <linux/kref.h>
+
+struct vfsmount;
+
+struct mq_namespace {
+	struct kref	kref;
+	struct vfsmount *mnt;
+
+	unsigned int	queues_count;
+	unsigned int	queues_max;
+	unsigned int	msg_max;
+	unsigned int	msgsize_max;
+};
+
+extern struct mq_namespace init_mq_ns;
+
+/* default values */
+#define DFLT_QUEUESMAX	256	/* max number of message queues */
+#define DFLT_MSGMAX 	10	/* max number of messages in each queue */
+#define HARD_MSGMAX 	(131072/sizeof(void *))
+#define DFLT_MSGSIZEMAX 8192	/* max message size */
+
+#ifdef CONFIG_POSIX_MQUEUE
+#define INIT_MQ_NS(ns)		.ns		= &init_mq_ns,
+#else
+#define INIT_MQ_NS(ns)
+#endif
+
+#if defined(CONFIG_POSIX_MQUEUE) && defined(CONFIG_MQ_NS)
+static inline struct mq_namespace *get_mq_ns(struct mq_namespace *ns)
+{
+	if (ns)
+		kref_get(&ns->kref);
+	return ns;
+}
+
+extern struct mq_namespace *copy_mq_ns(unsigned long clone_flags,
+				struct mq_namespace *old_ns);
+extern void free_mq_ns(struct kref *kref);
+
+static inline void put_mq_ns(struct mq_namespace *ns)
+{
+	if (ns)
+		kref_put(&ns->kref, free_mq_ns);
+}
+
+#else
+
+static inline struct mq_namespace *get_mq_ns(struct mq_namespace *ns)
+{
+	return ns;
+}
+
+static inline struct mq_namespace *copy_mq_ns(unsigned long clone_flags,
+					struct mq_namespace *old_ns)
+{
+	return old_ns;
+}
+
+static inline void put_mq_ns(struct mq_namespace *ns) { }
+
+#endif /* CONFIG_POSIX_MQUEUE */
+
+#endif /* _LINUX_MQ_H */
diff -puN init/Kconfig~mq_namespace-add-mq_namespace init/Kconfig
--- linux-2.6.git/init/Kconfig~mq_namespace-add-mq_namespace	2008-06-24 12:03:16.000000000 -0700
+++ linux-2.6.git-dave/init/Kconfig	2008-06-24 12:03:16.000000000 -0700
@@ -493,6 +493,15 @@ config PID_NS
 	  Unless you want to work with an experimental feature
 	  say N here.
 
+config MQ_NS
+       bool "POSIX Message Queues namespace"
+       depends on NAMESPACES && POSIX_MQUEUE
+       help
+	 Support for POSIX Message Queues namespaces. This allows
+	 having different POSIX Message Queues filesystems containing
+	 message queues with the same name. Yet another a building
+	 block of containers.
+
 config BLK_DEV_INITRD
 	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 	depends on BROKEN || !FRV
diff -puN ipc/Makefile~mq_namespace-add-mq_namespace ipc/Makefile
--- linux-2.6.git/ipc/Makefile~mq_namespace-add-mq_namespace	2008-06-24 12:03:16.000000000 -0700
+++ linux-2.6.git-dave/ipc/Makefile	2008-06-24 12:03:16.000000000 -0700
@@ -8,4 +8,5 @@ obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysc
 obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
 obj-$(CONFIG_IPC_NS) += namespace.o
+obj-$(CONFIG_MQ_NS) += mq_namespace.o
 
diff -puN /dev/null ipc/mq_namespace.c
--- /dev/null	2007-04-11 11:48:27.000000000 -0700
+++ linux-2.6.git-dave/ipc/mq_namespace.c	2008-06-24 12:03:16.000000000 -0700
@@ -0,0 +1,23 @@
+/*
+ *  Copyright (C) 2007 IBM Corporation
+ *
+ *  Author: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License as
+ *  published by the Free Software Foundation, version 2 of the
+ *  License.
+ */
+
+#include <linux/mq_namespace.h>
+
+struct mq_namespace *copy_mq_ns(unsigned long clone_flags,
+				struct mq_namespace *old_ns)
+{
+	BUG_ON(!old_ns);
+	return get_mq_ns(old_ns);
+}
+
+void free_mq_ns(struct kref *kref)
+{
+}
diff -puN ipc/mqueue.c~mq_namespace-add-mq_namespace ipc/mqueue.c
--- linux-2.6.git/ipc/mqueue.c~mq_namespace-add-mq_namespace	2008-06-24 12:03:16.000000000 -0700
+++ linux-2.6.git-dave/ipc/mqueue.c	2008-06-24 12:03:16.000000000 -0700
@@ -31,6 +31,7 @@
 #include <linux/mutex.h>
 #include <linux/nsproxy.h>
 #include <linux/pid.h>
+#include <linux/mq_namespace.h>
 
 #include <net/sock.h>
 #include "util.h"
@@ -46,13 +47,6 @@
 #define STATE_PENDING	1
 #define STATE_READY	2
 
-/* default values */
-#define DFLT_QUEUESMAX	256	/* max number of message queues */
-#define DFLT_MSGMAX 	10	/* max number of messages in each queue */
-#define HARD_MSGMAX 	(131072/sizeof(void*))
-#define DFLT_MSGSIZEMAX 8192	/* max message size */
-
-
 struct ext_wait_queue {		/* queue of sleeping tasks */
 	struct task_struct *task;
 	struct list_head list;
@@ -87,12 +81,18 @@ static void remove_notification(struct m
 
 static spinlock_t mq_lock;
 static struct kmem_cache *mqueue_inode_cachep;
-static struct vfsmount *mqueue_mnt;
 
-static unsigned int queues_count;
-static unsigned int queues_max 	= DFLT_QUEUESMAX;
-static unsigned int msg_max 	= DFLT_MSGMAX;
-static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
+struct mq_namespace init_mq_ns = {
+	.kref = {
+		.refcount = ATOMIC_INIT(2),
+	},
+	.mnt		= NULL,
+	.queues_count	= 0,
+	.queues_max 	= DFLT_QUEUESMAX,
+	.msg_max 	= DFLT_MSGMAX,
+	.msgsize_max	= DFLT_MSGSIZEMAX,
+};
+
 
 static struct ctl_table_header * mq_sysctl_table;
 
@@ -235,6 +235,7 @@ static void mqueue_delete_inode(struct i
 	struct user_struct *user;
 	unsigned long mq_bytes;
 	int i;
+	struct mq_namespace *mq_ns = &init_mq_ns;
 
 	if (S_ISDIR(inode->i_mode)) {
 		clear_inode(inode);
@@ -255,7 +256,7 @@ static void mqueue_delete_inode(struct i
 	if (user) {
 		spin_lock(&mq_lock);
 		user->mq_bytes -= mq_bytes;
-		queues_count--;
+		mq_ns->queues_count--;
 		spin_unlock(&mq_lock);
 		free_uid(user);
 	}
@@ -267,20 +268,22 @@ static int mqueue_create(struct inode *d
 	struct inode *inode;
 	struct mq_attr *attr = dentry->d_fsdata;
 	int error;
+	struct mq_namespace *mq_ns = &init_mq_ns;
 
 	spin_lock(&mq_lock);
-	if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
+	if (mq_ns->queues_count >= mq_ns->queues_max &&
+		!capable(CAP_SYS_RESOURCE)) {
 		error = -ENOSPC;
 		goto out_lock;
 	}
-	queues_count++;
+	mq_ns->queues_count++;
 	spin_unlock(&mq_lock);
 
 	inode = mqueue_get_inode(dir->i_sb, mode, attr);
 	if (!inode) {
 		error = -ENOMEM;
 		spin_lock(&mq_lock);
-		queues_count--;
+		mq_ns->queues_count--;
 		goto out_lock;
 	}
 
@@ -569,7 +572,7 @@ static void remove_notification(struct m
 	info->notify_owner = NULL;
 }
 
-static int mq_attr_ok(struct mq_attr *attr)
+static int mq_attr_ok(struct mq_namespace *mq_ns, struct mq_attr *attr)
 {
 	if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
 		return 0;
@@ -577,8 +580,8 @@ static int mq_attr_ok(struct mq_attr *at
 		if (attr->mq_maxmsg > HARD_MSGMAX)
 			return 0;
 	} else {
-		if (attr->mq_maxmsg > msg_max ||
-				attr->mq_msgsize > msgsize_max)
+		if (attr->mq_maxmsg > mq_ns->msg_max ||
+				attr->mq_msgsize > mq_ns->msgsize_max)
 			return 0;
 	}
 	/* check for overflow */
@@ -594,8 +597,9 @@ static int mq_attr_ok(struct mq_attr *at
 /*
  * Invoked when creating a new queue via sys_mq_open
  */
-static struct file *do_create(struct dentry *dir, struct dentry *dentry,
-			int oflag, mode_t mode, struct mq_attr __user *u_attr)
+static struct file *do_create(struct mq_namespace *mq_ns, struct dentry *dir,
+			struct dentry *dentry, int oflag, mode_t mode,
+			struct mq_attr __user *u_attr)
 {
 	struct mq_attr attr;
 	struct file *result;
@@ -606,14 +610,14 @@ static struct file *do_create(struct den
 		if (copy_from_user(&attr, u_attr, sizeof(attr)))
 			goto out;
 		ret = -EINVAL;
-		if (!mq_attr_ok(&attr))
+		if (!mq_attr_ok(mq_ns, &attr))
 			goto out;
 		/* store for use during create */
 		dentry->d_fsdata = &attr;
 	}
 
 	mode &= ~current->fs->umask;
-	ret = mnt_want_write(mqueue_mnt);
+	ret = mnt_want_write(mq_ns->mnt);
 	if (ret)
 		goto out;
 	ret = vfs_create(dir->d_inode, dentry, mode, NULL);
@@ -621,41 +625,42 @@ static struct file *do_create(struct den
 	if (ret)
 		goto out_drop_write;
 
-	result = dentry_open(dentry, mqueue_mnt, oflag);
+	result = dentry_open(dentry, mq_ns->mnt, oflag);
 	/*
 	 * dentry_open() took a persistent mnt_want_write(),
 	 * so we can now drop this one.
 	 */
-	mnt_drop_write(mqueue_mnt);
+	mnt_drop_write(mq_ns->mnt);
 	return result;
 
 out_drop_write:
-	mnt_drop_write(mqueue_mnt);
+	mnt_drop_write(mq_ns->mnt);
 out:
 	dput(dentry);
-	mntput(mqueue_mnt);
+	mntput(mq_ns->mnt);
 	return ERR_PTR(ret);
 }
 
 /* Opens existing queue */
-static struct file *do_open(struct dentry *dentry, int oflag)
+static struct file *do_open(struct mq_namespace *mq_ns, struct dentry *dentry,
+			int oflag)
 {
-static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
+	static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 					MAY_READ | MAY_WRITE };
 
 	if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
 		dput(dentry);
-		mntput(mqueue_mnt);
+		mntput(mq_ns->mnt);
 		return ERR_PTR(-EINVAL);
 	}
 
 	if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) {
 		dput(dentry);
-		mntput(mqueue_mnt);
+		mntput(mq_ns->mnt);
 		return ERR_PTR(-EACCES);
 	}
 
-	return dentry_open(dentry, mqueue_mnt, oflag);
+	return dentry_open(dentry, mq_ns->mnt, oflag);
 }
 
 asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
@@ -665,6 +670,7 @@ asmlinkage long sys_mq_open(const char _
 	struct file *filp;
 	char *name;
 	int fd, error;
+	struct mq_namespace *mq_ns = &init_mq_ns;
 
 	error = audit_mq_open(oflag, mode, u_attr);
 	if (error != 0)
@@ -677,13 +683,13 @@ asmlinkage long sys_mq_open(const char _
 	if (fd < 0)
 		goto out_putname;
 
-	mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
-	dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
+	mutex_lock(&mq_ns->mnt->mnt_root->d_inode->i_mutex);
+	dentry = lookup_one_len(name, mq_ns->mnt->mnt_root, strlen(name));
 	if (IS_ERR(dentry)) {
 		error = PTR_ERR(dentry);
 		goto out_err;
 	}
-	mntget(mqueue_mnt);
+	mntget(mq_ns->mnt);
 
 	if (oflag & O_CREAT) {
 		if (dentry->d_inode) {	/* entry already exists */
@@ -691,9 +697,9 @@ asmlinkage long sys_mq_open(const char _
 			error = -EEXIST;
 			if (oflag & O_EXCL)
 				goto out;
-			filp = do_open(dentry, oflag);
+			filp = do_open(mq_ns, dentry, oflag);
 		} else {
-			filp = do_create(mqueue_mnt->mnt_root, dentry,
+			filp = do_create(mq_ns, mq_ns->mnt->mnt_root, dentry,
 						oflag, mode, u_attr);
 		}
 	} else {
@@ -701,7 +707,7 @@ asmlinkage long sys_mq_open(const char _
 		if (!dentry->d_inode)
 			goto out;
 		audit_inode(name, dentry);
-		filp = do_open(dentry, oflag);
+		filp = do_open(mq_ns, dentry, oflag);
 	}
 
 	if (IS_ERR(filp)) {
@@ -714,13 +720,13 @@ asmlinkage long sys_mq_open(const char _
 
 out:
 	dput(dentry);
-	mntput(mqueue_mnt);
+	mntput(mq_ns->mnt);
 out_putfd:
 	put_unused_fd(fd);
 out_err:
 	fd = error;
 out_upsem:
-	mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
+	mutex_unlock(&mq_ns->mnt->mnt_root->d_inode->i_mutex);
 out_putname:
 	putname(name);
 	return fd;
@@ -732,14 +738,15 @@ asmlinkage long sys_mq_unlink(const char
 	char *name;
 	struct dentry *dentry;
 	struct inode *inode = NULL;
+	struct mq_namespace *mq_ns = &init_mq_ns;
 
 	name = getname(u_name);
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
-	mutex_lock_nested(&mqueue_mnt->mnt_root->d_inode->i_mutex,
+	mutex_lock_nested(&mq_ns->mnt->mnt_root->d_inode->i_mutex,
 			I_MUTEX_PARENT);
-	dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
+	dentry = lookup_one_len(name, mq_ns->mnt->mnt_root, strlen(name));
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
 		goto out_unlock;
@@ -753,16 +760,16 @@ asmlinkage long sys_mq_unlink(const char
 	inode = dentry->d_inode;
 	if (inode)
 		atomic_inc(&inode->i_count);
-	err = mnt_want_write(mqueue_mnt);
+	err = mnt_want_write(mq_ns->mnt);
 	if (err)
 		goto out_err;
 	err = vfs_unlink(dentry->d_parent->d_inode, dentry);
-	mnt_drop_write(mqueue_mnt);
+	mnt_drop_write(mq_ns->mnt);
 out_err:
 	dput(dentry);
 
 out_unlock:
-	mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
+	mutex_unlock(&mq_ns->mnt->mnt_root->d_inode->i_mutex);
 	putname(name);
 	if (inode)
 		iput(inode);
@@ -1211,14 +1218,14 @@ static int msg_maxsize_limit_max = INT_M
 static ctl_table mq_sysctls[] = {
 	{
 		.procname	= "queues_max",
-		.data		= &queues_max,
+		.data		= &init_mq_ns.queues_max,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec,
 	},
 	{
 		.procname	= "msg_max",
-		.data		= &msg_max,
+		.data		= &init_mq_ns.msg_max,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec_minmax,
@@ -1227,7 +1234,7 @@ static ctl_table mq_sysctls[] = {
 	},
 	{
 		.procname	= "msgsize_max",
-		.data		= &msgsize_max,
+		.data		= &init_mq_ns.msgsize_max,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec_minmax,
@@ -1273,13 +1280,13 @@ static int __init init_mqueue_fs(void)
 	if (error)
 		goto out_sysctl;
 
-	if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
-		error = PTR_ERR(mqueue_mnt);
+	init_mq_ns.mnt = kern_mount(&mqueue_fs_type);
+	if (IS_ERR(init_mq_ns.mnt)) {
+		error = PTR_ERR(init_mq_ns.mnt);
 		goto out_filesystem;
 	}
 
 	/* internal initialization - not common for vfs */
-	queues_count = 0;
 	spin_lock_init(&mq_lock);
 
 	return 0;
_

[RFC][PATCH 3/5] fs: add get_sb_single_ns() helper routine

[Dave Hansen]

From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>

This patch add a helper routine get_sb_single_ns() which allocates
a single super_block per instance of namespace. The data parameter
is used to differentiate the namespaces.

This is used in subsystems with an internal fs like mqueue. 

TODO:
	- use in pidns and devpts 

Signed-off-by: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
---

 linux-2.6.git-dave/fs/super.c         |   37 ++++++++++++++++++++++++++++++++++
 linux-2.6.git-dave/include/linux/fs.h |    4 +++
 2 files changed, 41 insertions(+)

diff -puN fs/super.c~add-get_sb_single_ns-helper fs/super.c
--- linux-2.6.git/fs/super.c~add-get_sb_single_ns-helper	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/fs/super.c	2008-06-24 12:03:17.000000000 -0700
@@ -882,6 +882,43 @@ int get_sb_single(struct file_system_typ
 
 EXPORT_SYMBOL(get_sb_single);
 
+static int compare_sb_single_ns(struct super_block *sb, void *data)
+{
+	return sb->s_fs_info == data;
+}
+
+static int set_sb_single_ns(struct super_block *sb, void *data)
+{
+	sb->s_fs_info = data;
+	return set_anon_super(sb, data);
+}
+
+int get_sb_single_ns(struct file_system_type *fs_type,
+	int flags, void *data,
+	int (*fill_super)(struct super_block *, void *, int),
+	struct vfsmount *mnt)
+{
+	struct super_block *s;
+	int error;
+
+	s = sget(fs_type, compare_sb_single_ns, set_sb_single_ns, data);
+	if (IS_ERR(s))
+		return PTR_ERR(s);
+	if (!s->s_root) {
+		s->s_flags = flags;
+		error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
+		if (error) {
+			up_write(&s->s_umount);
+			deactivate_super(s);
+			return error;
+		}
+		s->s_flags |= MS_ACTIVE;
+	}
+	do_remount_sb(s, flags, data, 0);
+	return simple_set_mnt(mnt, s);
+}
+EXPORT_SYMBOL(get_sb_single_ns);
+
 struct vfsmount *
 vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
 {
diff -puN include/linux/fs.h~add-get_sb_single_ns-helper include/linux/fs.h
--- linux-2.6.git/include/linux/fs.h~add-get_sb_single_ns-helper	2008-06-24 12:03:17.000000000 -0700
+++ linux-2.6.git-dave/include/linux/fs.h	2008-06-24 12:03:17.000000000 -0700
@@ -1502,6 +1502,10 @@ extern int get_sb_nodev(struct file_syst
 	int flags, void *data,
 	int (*fill_super)(struct super_block *, void *, int),
 	struct vfsmount *mnt);
+extern int get_sb_single_ns(struct file_system_type *fs_type,
+	int flags, void *data,
+	int (*fill_super)(struct super_block *, void *, int),
+	struct vfsmount *mnt);
 void generic_shutdown_super(struct super_block *sb);
 void kill_block_super(struct super_block *sb);
 void kill_anon_super(struct super_block *sb);
_

[RFC][PATCH 4/5] mqueue namespace: enable the mqueue namespace

[Dave Hansen]

From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>

Move forward and start using the mqueue namespace.

The single super block mount of the file system is modified to allow 
one mount per namespace. This is achieved by storing the namespace 
in the super_block s_fs_info attribute. 

Changes since v5 Feb 28, 2008: 

	* fix race on sb->s_fs_info when the namespace is freed 

Changes since v4: 

	* check mq_ns validity when the message queue is accessed
	  through a user mount and eventually return -EACCES if
	  mq_ns is bogus

Signed-off-by: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
---

 linux-2.6.git-dave/include/linux/mq_namespace.h |    2 +
 linux-2.6.git-dave/ipc/mq_namespace.c           |   10 +++++-
 linux-2.6.git-dave/ipc/mqueue.c                 |   37 ++++++++++++++++++------
 3 files changed, 40 insertions(+), 9 deletions(-)

diff -puN include/linux/mq_namespace.h~mq_namespace-use-mq_namespace include/linux/mq_namespace.h
--- linux-2.6.git/include/linux/mq_namespace.h~mq_namespace-use-mq_namespace	2008-06-24 12:03:18.000000000 -0700
+++ linux-2.6.git-dave/include/linux/mq_namespace.h	2008-06-24 12:03:18.000000000 -0700
@@ -3,6 +3,7 @@
 
 #include <linux/kref.h>
 #include <linux/err.h>
+#include <linux/fs.h>
 
 struct vfsmount;
 
@@ -17,6 +18,7 @@ struct mq_namespace {
 };
 
 extern struct mq_namespace init_mq_ns;
+extern struct file_system_type mqueue_fs_type;
 
 /* default values */
 #define DFLT_QUEUESMAX	256	/* max number of message queues */
diff -puN ipc/mq_namespace.c~mq_namespace-use-mq_namespace ipc/mq_namespace.c
--- linux-2.6.git/ipc/mq_namespace.c~mq_namespace-use-mq_namespace	2008-06-24 12:03:18.000000000 -0700
+++ linux-2.6.git-dave/ipc/mq_namespace.c	2008-06-24 12:03:18.000000000 -0700
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/err.h>
+#include <linux/mount.h>
 
 static struct mq_namespace *clone_mq_ns(struct mq_namespace *old_ns)
 {
@@ -27,7 +28,12 @@ static struct mq_namespace *clone_mq_ns(
 	mq_ns->queues_max	= DFLT_QUEUESMAX;
 	mq_ns->msg_max		= DFLT_MSGMAX;
 	mq_ns->msgsize_max	= DFLT_MSGSIZEMAX;
-	mq_ns->mnt		= NULL;
+	mq_ns->mnt		= kern_mount_data(&mqueue_fs_type, mq_ns);
+	if (IS_ERR(mq_ns->mnt)) {
+		void *error = mq_ns->mnt;
+		kfree(mq_ns);
+		return error;
+	}
 	return mq_ns;
 }
 
@@ -53,5 +59,7 @@ void free_mq_ns(struct kref *kref)
 	struct mq_namespace *ns;
 
 	ns = container_of(kref, struct mq_namespace, kref);
+	ns->mnt->mnt_sb->s_fs_info = NULL;
+	mntput(ns->mnt);
 	kfree(ns);
 }
diff -puN ipc/mqueue.c~mq_namespace-use-mq_namespace ipc/mqueue.c
--- linux-2.6.git/ipc/mqueue.c~mq_namespace-use-mq_namespace	2008-06-24 12:03:18.000000000 -0700
+++ linux-2.6.git-dave/ipc/mqueue.c	2008-06-24 12:03:18.000000000 -0700
@@ -204,7 +204,10 @@ static int mqueue_get_sb(struct file_sys
 			 int flags, const char *dev_name,
 			 void *data, struct vfsmount *mnt)
 {
-	return get_sb_single(fs_type, flags, data, mqueue_fill_super, mnt);
+	if (!(flags & MS_KERNMOUNT))
+		data = current->nsproxy->mq_ns;
+
+	return get_sb_single_ns(fs_type, flags, data, mqueue_fill_super, mnt);
 }
 
 static void init_once(struct kmem_cache *cachep, void *foo)
@@ -235,7 +238,7 @@ static void mqueue_delete_inode(struct i
 	struct user_struct *user;
 	unsigned long mq_bytes;
 	int i;
-	struct mq_namespace *mq_ns = &init_mq_ns;
+	struct mq_namespace *mq_ns = inode->i_sb->s_fs_info;
 
 	if (S_ISDIR(inode->i_mode)) {
 		clear_inode(inode);
@@ -256,7 +259,8 @@ static void mqueue_delete_inode(struct i
 	if (user) {
 		spin_lock(&mq_lock);
 		user->mq_bytes -= mq_bytes;
-		mq_ns->queues_count--;
+		if (mq_ns)
+			mq_ns->queues_count--;
 		spin_unlock(&mq_lock);
 		free_uid(user);
 	}
@@ -268,7 +272,15 @@ static int mqueue_create(struct inode *d
 	struct inode *inode;
 	struct mq_attr *attr = dentry->d_fsdata;
 	int error;
-	struct mq_namespace *mq_ns = &init_mq_ns;
+	struct mq_namespace *mq_ns = dir->i_sb->s_fs_info;
+
+	/*
+	 * There is a race on sb->s_fs_info with free_mq_ns() but it
+	 * shouldn't be an issue as we are only interested in
+	 * current->nsproxy->mq_ns which is valid.
+	 */
+	if (mq_ns != current->nsproxy->mq_ns)
+		return -EACCES;
 
 	spin_lock(&mq_lock);
 	if (mq_ns->queues_count >= mq_ns->queues_max &&
@@ -301,6 +313,15 @@ out_lock:
 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 {
   	struct inode *inode = dentry->d_inode;
+	struct mq_namespace *mq_ns = dir->i_sb->s_fs_info;
+
+	/*
+	 * There is a race on sb->s_fs_info with free_mq_ns() but it
+	 * shouldn't be an issue as we are only interested in
+	 * current->nsproxy->mq_ns which is valid.
+	 */
+	if (mq_ns != current->nsproxy->mq_ns)
+		return -EACCES;
 
 	dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 	dir->i_size -= DIRENT_SIZE;
@@ -670,7 +691,7 @@ asmlinkage long sys_mq_open(const char _
 	struct file *filp;
 	char *name;
 	int fd, error;
-	struct mq_namespace *mq_ns = &init_mq_ns;
+	struct mq_namespace *mq_ns = current->nsproxy->mq_ns;
 
 	error = audit_mq_open(oflag, mode, u_attr);
 	if (error != 0)
@@ -738,7 +759,7 @@ asmlinkage long sys_mq_unlink(const char
 	char *name;
 	struct dentry *dentry;
 	struct inode *inode = NULL;
-	struct mq_namespace *mq_ns = &init_mq_ns;
+	struct mq_namespace *mq_ns = current->nsproxy->mq_ns;
 
 	name = getname(u_name);
 	if (IS_ERR(name))
@@ -1203,7 +1224,7 @@ static struct super_operations mqueue_su
 	.drop_inode = generic_delete_inode,
 };
 
-static struct file_system_type mqueue_fs_type = {
+struct file_system_type mqueue_fs_type = {
 	.name = "mqueue",
 	.get_sb = mqueue_get_sb,
 	.kill_sb = kill_litter_super,
@@ -1280,7 +1301,7 @@ static int __init init_mqueue_fs(void)
 	if (error)
 		goto out_sysctl;
 
-	init_mq_ns.mnt = kern_mount(&mqueue_fs_type);
+	init_mq_ns.mnt = kern_mount_data(&mqueue_fs_type, &init_mq_ns);
 	if (IS_ERR(init_mq_ns.mnt)) {
 		error = PTR_ERR(init_mq_ns.mnt);
 		goto out_filesystem;
_

[RFC][PATCH 5/5] Subject: mqueue namespace: adapt sysctl

[Dave Hansen]

From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>

Largely inspired from ipc/ipc_sysctl.c. This patch isolates the mqueue 
sysctl stuff in its own file.

Signed-off-by: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
---

 linux-2.6.git-dave/include/linux/mq_namespace.h |   10 ++
 linux-2.6.git-dave/init/Kconfig                 |    6 +
 linux-2.6.git-dave/ipc/Makefile                 |    1 
 linux-2.6.git-dave/ipc/mq_sysctl.c              |  117 ++++++++++++++++++++++++
 linux-2.6.git-dave/ipc/mqueue.c                 |   56 -----------
 5 files changed, 135 insertions(+), 55 deletions(-)

diff -puN include/linux/mq_namespace.h~mq_namespace-fix-sysctl include/linux/mq_namespace.h
--- linux-2.6.git/include/linux/mq_namespace.h~mq_namespace-fix-sysctl	2008-06-24 12:03:19.000000000 -0700
+++ linux-2.6.git-dave/include/linux/mq_namespace.h	2008-06-24 12:03:19.000000000 -0700
@@ -67,4 +67,14 @@ static inline void put_mq_ns(struct mq_n
 
 #endif /* CONFIG_POSIX_MQUEUE */
 
+#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
+struct ctl_table_header;
+extern struct ctl_table_header *mq_register_sysctl_table(void);
+#else
+static inline struct ctl_table_header *mq_register_sysctl_table(void)
+{
+	return NULL;
+}
+#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
+
 #endif /* _LINUX_MQ_H */
diff -puN init/Kconfig~mq_namespace-fix-sysctl init/Kconfig
--- linux-2.6.git/init/Kconfig~mq_namespace-fix-sysctl	2008-06-24 12:03:19.000000000 -0700
+++ linux-2.6.git-dave/init/Kconfig	2008-06-24 12:03:19.000000000 -0700
@@ -148,6 +148,12 @@ config POSIX_MQUEUE
 
 	  If unsure, say Y.
 
+config POSIX_MQUEUE_SYSCTL
+	bool
+	depends on POSIX_MQUEUE
+	depends on SYSCTL
+	default y
+
 config BSD_PROCESS_ACCT
 	bool "BSD Process Accounting"
 	help
diff -puN ipc/Makefile~mq_namespace-fix-sysctl ipc/Makefile
--- linux-2.6.git/ipc/Makefile~mq_namespace-fix-sysctl	2008-06-24 12:03:19.000000000 -0700
+++ linux-2.6.git-dave/ipc/Makefile	2008-06-24 12:03:19.000000000 -0700
@@ -9,4 +9,5 @@ obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
 obj-$(CONFIG_IPC_NS) += namespace.o
 obj-$(CONFIG_MQ_NS) += mq_namespace.o
+obj-$(CONFIG_POSIX_MQUEUE_SYSCTL) += mq_sysctl.o
 
diff -puN /dev/null ipc/mq_sysctl.c
--- /dev/null	2007-04-11 11:48:27.000000000 -0700
+++ linux-2.6.git-dave/ipc/mq_sysctl.c	2008-06-24 12:03:19.000000000 -0700
@@ -0,0 +1,117 @@
+/*
+ *  Copyright (C) 2007 IBM Corporation
+ *
+ *  Author: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License as
+ *  published by the Free Software Foundation, version 2 of the
+ *  License.
+ */
+
+#include <linux/nsproxy.h>
+#include <linux/mq_namespace.h>
+#include <linux/sysctl.h>
+
+
+static void *get_mq(ctl_table *table)
+{
+	char *which = table->data;
+	struct mq_namespace *mq_ns = current->nsproxy->mq_ns;
+	which = (which - (char *)&init_mq_ns) + (char *)mq_ns;
+	return which;
+}
+
+#ifdef CONFIG_PROC_FS
+static int proc_mq_dointvec(ctl_table *table, int write, struct file *filp,
+	void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table mq_table;
+	memcpy(&mq_table, table, sizeof(mq_table));
+	mq_table.data = get_mq(table);
+
+	return proc_dointvec(&mq_table, write, filp, buffer, lenp, ppos);
+}
+
+static int proc_mq_dointvec_minmax(ctl_table *table, int write,
+	struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table mq_table;
+	memcpy(&mq_table, table, sizeof(mq_table));
+	mq_table.data = get_mq(table);
+
+	return proc_dointvec_minmax(&mq_table, write, filp, buffer,
+					lenp, ppos);
+}
+#else
+static int proc_mq_dointvec(ctl_table *table, int write, struct file *filp,
+	void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+
+static int proc_mq_dointvec_minmax(ctl_table *table, int write,
+	struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	return -ENOSYS;
+}
+#endif
+
+static int msg_max_limit_min = DFLT_MSGMAX;
+static int msg_max_limit_max = HARD_MSGMAX;
+
+static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
+static int msg_maxsize_limit_max = INT_MAX;
+
+static ctl_table mq_sysctls[] = {
+	{
+		.procname	= "queues_max",
+		.data		= &init_mq_ns.queues_max,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_mq_dointvec,
+	},
+	{
+		.procname	= "msg_max",
+		.data		= &init_mq_ns.msg_max,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_mq_dointvec_minmax,
+		.extra1		= &msg_max_limit_min,
+		.extra2		= &msg_max_limit_max,
+	},
+	{
+		.procname	= "msgsize_max",
+		.data		= &init_mq_ns.msgsize_max,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_mq_dointvec_minmax,
+		.extra1		= &msg_maxsize_limit_min,
+		.extra2		= &msg_maxsize_limit_max,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table mq_sysctl_dir[] = {
+	{
+		.procname	= "mqueue",
+		.mode		= 0555,
+		.child		= mq_sysctls,
+	},
+	{ .ctl_name = 0 }
+};
+
+static ctl_table mq_sysctl_root[] = {
+	{
+		.ctl_name	= CTL_FS,
+		.procname	= "fs",
+		.mode		= 0555,
+		.child		= mq_sysctl_dir,
+	},
+	{ .ctl_name = 0 }
+};
+
+struct ctl_table_header *mq_register_sysctl_table(void)
+{
+	return register_sysctl_table(mq_sysctl_root);
+}
diff -puN ipc/mqueue.c~mq_namespace-fix-sysctl ipc/mqueue.c
--- linux-2.6.git/ipc/mqueue.c~mq_namespace-fix-sysctl	2008-06-24 12:03:19.000000000 -0700
+++ linux-2.6.git-dave/ipc/mqueue.c	2008-06-24 12:03:19.000000000 -0700
@@ -1230,60 +1230,6 @@ struct file_system_type mqueue_fs_type =
 	.kill_sb = kill_litter_super,
 };
 
-static int msg_max_limit_min = DFLT_MSGMAX;
-static int msg_max_limit_max = HARD_MSGMAX;
-
-static int msg_maxsize_limit_min = DFLT_MSGSIZEMAX;
-static int msg_maxsize_limit_max = INT_MAX;
-
-static ctl_table mq_sysctls[] = {
-	{
-		.procname	= "queues_max",
-		.data		= &init_mq_ns.queues_max,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec,
-	},
-	{
-		.procname	= "msg_max",
-		.data		= &init_mq_ns.msg_max,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec_minmax,
-		.extra1		= &msg_max_limit_min,
-		.extra2		= &msg_max_limit_max,
-	},
-	{
-		.procname	= "msgsize_max",
-		.data		= &init_mq_ns.msgsize_max,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec_minmax,
-		.extra1		= &msg_maxsize_limit_min,
-		.extra2		= &msg_maxsize_limit_max,
-	},
-	{ .ctl_name = 0 }
-};
-
-static ctl_table mq_sysctl_dir[] = {
-	{
-		.procname	= "mqueue",
-		.mode		= 0555,
-		.child		= mq_sysctls,
-	},
-	{ .ctl_name = 0 }
-};
-
-static ctl_table mq_sysctl_root[] = {
-	{
-		.ctl_name	= CTL_FS,
-		.procname	= "fs",
-		.mode		= 0555,
-		.child		= mq_sysctl_dir,
-	},
-	{ .ctl_name = 0 }
-};
-
 static int __init init_mqueue_fs(void)
 {
 	int error;
@@ -1295,7 +1241,7 @@ static int __init init_mqueue_fs(void)
 		return -ENOMEM;
 
 	/* ignore failues - they are not fatal */
-	mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
+	mq_sysctl_table = mq_register_sysctl_table();
 
 	error = register_filesystem(&mqueue_fs_type);
 	if (error)
_

Re: [RFC][PATCH 2/5] mqueue namespace: add unshare support

[Daniel Hokka Zakrisson]

"Dave Hansen" <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
>
>
> From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
>
> This patch includes the mqueue namespace in the nsproxy object. It
> also adds the support of unshare() and clone() with a new clone flag.
                                                        ^^^

> It's totally harmless for the moment because the current code still
> uses the default mqueue namespace object 'init_mq_ns'
>
> Changes since v6 Mar 05, 2008:
>
> 	* dropped new clone flag CLONE_NEWMQ and used CLONE_NEWIPC
> 	  instead

Maybe the description above should be updated too?

> Changes since v5 Feb 28, 2008:
>
> 	* fix typo in create_new_namespaces()
>
> Changes since v4:
>
> 	* remove CLONE_NEWNS enforcement. stalled user mounts are
> 	  handled in the fs ops.
>
> Signed-off-by: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
> ---
>
>  linux-2.6.git-dave/include/linux/init_task.h    |    2 +
>  linux-2.6.git-dave/include/linux/mq_namespace.h |    1
>  linux-2.6.git-dave/include/linux/nsproxy.h      |    2 +
>  linux-2.6.git-dave/ipc/mq_namespace.c           |   36
> +++++++++++++++++++++++-
>  linux-2.6.git-dave/kernel/nsproxy.c             |   11 +++++++
>  5 files changed, 51 insertions(+), 1 deletion(-)
>
> diff -puN
> include/linux/init_task.h~mq_namespace-add-mq_namespace-to-nsproxy
> include/linux/init_task.h
> ---
> linux-2.6.git/include/linux/init_task.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/include/linux/init_task.h	2008-06-24
> 12:03:17.000000000 -0700
> @@ -10,6 +10,7 @@
>  #include <linux/user_namespace.h>
>  #include <linux/securebits.h>
>  #include <net/net_namespace.h>
> +#include <linux/mq_namespace.h>
>
>  extern struct files_struct init_files;
>
> @@ -58,6 +59,7 @@ extern struct nsproxy init_nsproxy;
>  	INIT_NET_NS(net_ns)                                             \
>  	INIT_IPC_NS(ipc_ns)						\
>  	.user_ns	= &init_user_ns,				\
> +	INIT_MQ_NS(mq_ns)						\
>  }
>
>  #define INIT_SIGHAND(sighand) {						\
> diff -puN
> include/linux/mq_namespace.h~mq_namespace-add-mq_namespace-to-nsproxy
> include/linux/mq_namespace.h
> ---
> linux-2.6.git/include/linux/mq_namespace.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/include/linux/mq_namespace.h	2008-06-24
> 12:03:17.000000000 -0700
> @@ -2,6 +2,7 @@
>  #define _LINUX_MQ_NAMESPACE_H
>
>  #include <linux/kref.h>
> +#include <linux/err.h>

Why is this necessary (in this patch)?

>  struct vfsmount;
>
> diff -puN include/linux/nsproxy.h~mq_namespace-add-mq_namespace-to-nsproxy
> include/linux/nsproxy.h
> ---
> linux-2.6.git/include/linux/nsproxy.h~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/include/linux/nsproxy.h	2008-06-24
> 12:03:17.000000000 -0700
> @@ -8,6 +8,7 @@ struct mnt_namespace;
>  struct uts_namespace;
>  struct ipc_namespace;
>  struct pid_namespace;
> +struct mq_namespace;
>
>  /*
>   * A structure to contain pointers to all per-process
> @@ -29,6 +30,7 @@ struct nsproxy {
>  	struct pid_namespace *pid_ns;
>  	struct user_namespace *user_ns;
>  	struct net 	     *net_ns;
> +	struct mq_namespace *mq_ns;
>  };
>  extern struct nsproxy init_nsproxy;
>
> diff -puN ipc/mq_namespace.c~mq_namespace-add-mq_namespace-to-nsproxy
> ipc/mq_namespace.c
> ---
> linux-2.6.git/ipc/mq_namespace.c~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/ipc/mq_namespace.c	2008-06-24 12:03:17.000000000
> -0700
> @@ -10,14 +10,48 @@
>   */
>
>  #include <linux/mq_namespace.h>
> +#include <linux/slab.h>
> +#include <linux/sched.h>
> +#include <linux/err.h>
> +
> +static struct mq_namespace *clone_mq_ns(struct mq_namespace *old_ns)
> +{
> +	struct mq_namespace *mq_ns;
> +
> +	mq_ns = kmalloc(sizeof(struct mq_namespace), GFP_KERNEL);
> +	if (!mq_ns)
> +		return ERR_PTR(-ENOMEM);
> +
> +	kref_init(&mq_ns->kref);
> +	mq_ns->queues_count	= 0;
> +	mq_ns->queues_max	= DFLT_QUEUESMAX;
> +	mq_ns->msg_max		= DFLT_MSGMAX;
> +	mq_ns->msgsize_max	= DFLT_MSGSIZEMAX;
> +	mq_ns->mnt		= NULL;
> +	return mq_ns;
> +}
>
>  struct mq_namespace *copy_mq_ns(unsigned long clone_flags,
>  				struct mq_namespace *old_ns)
>  {
> +	struct mq_namespace *mq_ns;
> +
>  	BUG_ON(!old_ns);
> -	return get_mq_ns(old_ns);
> +	get_mq_ns(old_ns);
> +
> +	if (!(clone_flags & CLONE_NEWIPC))
> +		return old_ns;
> +
> +	mq_ns = clone_mq_ns(old_ns);
> +
> +	put_mq_ns(old_ns);
> +	return mq_ns;
>  }
>
>  void free_mq_ns(struct kref *kref)
>  {
> +	struct mq_namespace *ns;
> +
> +	ns = container_of(kref, struct mq_namespace, kref);
> +	kfree(ns);
>  }
> diff -puN kernel/nsproxy.c~mq_namespace-add-mq_namespace-to-nsproxy
> kernel/nsproxy.c
> ---
> linux-2.6.git/kernel/nsproxy.c~mq_namespace-add-mq_namespace-to-nsproxy	2008-06-24
> 12:03:17.000000000 -0700
> +++ linux-2.6.git-dave/kernel/nsproxy.c	2008-06-24 12:03:17.000000000
> -0700
> @@ -93,8 +93,17 @@ static struct nsproxy *create_new_namesp
>  		goto out_net;
>  	}
>
> +	new_nsp->mq_ns = copy_mq_ns(flags, tsk->nsproxy->mq_ns);
> +	if (IS_ERR(new_nsp->mq_ns)) {
> +		err = PTR_ERR(new_nsp->mq_ns);
> +		goto out_mq;
> +	}
> +
>  	return new_nsp;
>
> +out_mq:
> +	if (new_nsp->net_ns)
> +		put_net(new_nsp->net_ns);
>  out_net:
>  	if (new_nsp->user_ns)
>  		put_user_ns(new_nsp->user_ns);
> @@ -182,6 +191,8 @@ void free_nsproxy(struct nsproxy *ns)
>  		put_pid_ns(ns->pid_ns);
>  	if (ns->user_ns)
>  		put_user_ns(ns->user_ns);
> +	if (ns->mq_ns)
> +		put_mq_ns(ns->mq_ns);
>  	put_net(ns->net_ns);
>  	kmem_cache_free(nsproxy_cachep, ns);
>  }
> _

-- 
Daniel Hokka Zakrisson

Re: [RFC][PATCH 2/5] mqueue namespace: add unshare support

[Serge E. Hallyn]

(Sorry, Bastian's message seems to have hit a snag in the mailing list,
and I see no option to re-post it)

Quoting Bastian Blank <bastian-yyjItF7Rl6lg9hUCZPvPmw@public.gmane.org>
> Date: Fri, 11 Jul 2008 11:39:59 +0200
> From: Bastian Blank <bastian-yyjItF7Rl6lg9hUCZPvPmw@public.gmane.org>
> To: Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org
> Subject: Re: [RFC][PATCH 2/5] mqueue namespace: add unshare support
> 
> On Thu, Jul 10, 2008 at 03:30:48PM -0700, Dave Hansen wrote:
> > 	* dropped new clone flag CLONE_NEWMQ and used CLONE_NEWIPC 
> > 	  instead
> 
> Hmm, can't it be merged into the ipc namespace then?

That could be done, but since CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
are separate options, in order to keep ifdefs out of .c we'd still
have separate handlers for initializing the sysv and posixmqueue
portions of the ipcns.  So keeping two separate namespace structs
seems like a clean separation to me in this case.

-serge