[PATCH 2/9] namespaces: incorporate fs namespace into nsproxy
From: Serge E. Hallyn
Date: Thu May 18 2006 - 11:48:44 EST
This moves the mount namespace into the nsproxy. The mount
namespace count now refers to the number of nsproxies point
to it, rather than the number of tasks. As a result, the
unshare_namespace() function in kernel/fork.c no longer checks
whether it is being shared.
Signed-off-by: Serge Hallyn <serue@xxxxxxxxxx>
---
fs/namespace.c | 22 ++++++++--------------
fs/proc/base.c | 5 +++--
include/linux/init_task.h | 1 +
include/linux/namespace.h | 6 ++----
include/linux/nsproxy.h | 3 +++
include/linux/sched.h | 4 +---
kernel/exit.c | 5 -----
kernel/fork.c | 19 +++++++------------
kernel/nsproxy.c | 40 +++++++++++++++++++++++++++++++++++-----
9 files changed, 60 insertions(+), 45 deletions(-)
a06a931bb7f9f82df3267dfce14c8a9784ae68e4
diff --git a/fs/namespace.c b/fs/namespace.c
index 2c5f1f8..33330fe 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -133,7 +133,7 @@ struct vfsmount *lookup_mnt(struct vfsmo
static inline int check_mnt(struct vfsmount *mnt)
{
- return mnt->mnt_namespace == current->namespace;
+ return mnt->mnt_namespace == current->nsproxy->namespace;
}
static void touch_namespace(struct namespace *ns)
@@ -832,7 +832,7 @@ static int attach_recursive_mnt(struct v
if (parent_nd) {
detach_mnt(source_mnt, parent_nd);
attach_mnt(source_mnt, nd);
- touch_namespace(current->namespace);
+ touch_namespace(current->nsproxy->namespace);
} else {
mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
commit_tree(source_mnt);
@@ -1372,7 +1372,7 @@ dput_out:
*/
struct namespace *dup_namespace(struct task_struct *tsk, struct fs_struct *fs)
{
- struct namespace *namespace = tsk->namespace;
+ struct namespace *namespace = tsk->nsproxy->namespace;
struct namespace *new_ns;
struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
struct vfsmount *p, *q;
@@ -1439,7 +1439,7 @@ struct namespace *dup_namespace(struct t
int copy_namespace(int flags, struct task_struct *tsk)
{
- struct namespace *namespace = tsk->namespace;
+ struct namespace *namespace = tsk->nsproxy->namespace;
struct namespace *new_ns;
int err = 0;
@@ -1462,7 +1462,7 @@ int copy_namespace(int flags, struct tas
goto out;
}
- tsk->namespace = new_ns;
+ tsk->nsproxy->namespace = new_ns;
out:
put_namespace(namespace);
@@ -1685,7 +1685,7 @@ asmlinkage long sys_pivot_root(const cha
detach_mnt(user_nd.mnt, &root_parent);
attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */
attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
- touch_namespace(current->namespace);
+ touch_namespace(current->nsproxy->namespace);
spin_unlock(&vfsmount_lock);
chroot_fs_refs(&user_nd, &new_nd);
security_sb_post_pivotroot(&user_nd, &new_nd);
@@ -1711,7 +1711,6 @@ static void __init init_mount_tree(void)
{
struct vfsmount *mnt;
struct namespace *namespace;
- struct task_struct *g, *p;
mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
if (IS_ERR(mnt))
@@ -1727,13 +1726,8 @@ static void __init init_mount_tree(void)
namespace->root = mnt;
mnt->mnt_namespace = namespace;
- init_task.namespace = namespace;
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- get_namespace(namespace);
- p->namespace = namespace;
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
+ init_task.nsproxy->namespace = namespace;
+ get_namespace(namespace);
set_fs_pwd(current->fs, namespace->root, namespace->root->mnt_root);
set_fs_root(current->fs, namespace->root, namespace->root->mnt_root);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6cc77dc..f74acae 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -72,6 +72,7 @@
#include <linux/cpuset.h>
#include <linux/audit.h>
#include <linux/poll.h>
+#include <linux/nsproxy.h>
#include "internal.h"
/*
@@ -685,7 +686,7 @@ static int mounts_open(struct inode *ino
int ret = -EINVAL;
task_lock(task);
- namespace = task->namespace;
+ namespace = task->nsproxy->namespace;
if (namespace)
get_namespace(namespace);
task_unlock(task);
@@ -752,7 +753,7 @@ static int mountstats_open(struct inode
struct seq_file *m = file->private_data;
struct namespace *namespace;
task_lock(task);
- namespace = task->namespace;
+ namespace = task->nsproxy->namespace;
if (namespace)
get_namespace(namespace);
task_unlock(task);
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 79ec4ea..672dc04 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -70,6 +70,7 @@ extern struct nsproxy init_nsproxy;
#define INIT_NSPROXY(nsproxy) { \
.count = ATOMIC_INIT(1), \
.nslock = SPIN_LOCK_UNLOCKED, \
+ .namespace = NULL, \
}
#define INIT_SIGHAND(sighand) { \
diff --git a/include/linux/namespace.h b/include/linux/namespace.h
index 3abc8e3..d137009 100644
--- a/include/linux/namespace.h
+++ b/include/linux/namespace.h
@@ -4,6 +4,7 @@
#include <linux/mount.h>
#include <linux/sched.h>
+#include <linux/nsproxy.h>
struct namespace {
atomic_t count;
@@ -26,11 +27,8 @@ static inline void put_namespace(struct
static inline void exit_namespace(struct task_struct *p)
{
- struct namespace *namespace = p->namespace;
+ struct namespace *namespace = p->nsproxy->namespace;
if (namespace) {
- task_lock(p);
- p->namespace = NULL;
- task_unlock(p);
put_namespace(namespace);
}
}
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 7bdebfa..7ebe666 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -4,6 +4,8 @@
#include <linux/spinlock.h>
#include <linux/sched.h>
+struct namespace;
+
/*
* A structure to contain pointers to all per-process
* namespaces - fs (mount), uts, network, sysvipc, etc.
@@ -19,6 +21,7 @@
struct nsproxy {
atomic_t count;
spinlock_t nslock;
+ struct namespace *namespace;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4c0bbb3..f2c945b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -235,7 +235,6 @@ extern signed long schedule_timeout_inte
extern signed long schedule_timeout_uninterruptible(signed long timeout);
asmlinkage void schedule(void);
-struct namespace;
struct nsproxy;
/* Maximum number of active map areas.. This is a random (large) number */
@@ -807,8 +806,7 @@ struct task_struct {
struct fs_struct *fs;
/* open file information */
struct files_struct *files;
-/* namespace */
- struct namespace *namespace;
+/* namespaces */
struct nsproxy *nsproxy;
/* signal handlers */
struct signal_struct *signal;
diff --git a/kernel/exit.c b/kernel/exit.c
index da2fc84..240d0df 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -36,7 +36,6 @@
#include <linux/compat.h>
#include <linux/pipe_fs_i.h>
#include <linux/audit.h> /* for audit_free() */
-#include <linux/nsproxy.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -415,11 +414,8 @@ void daemonize(const char *name, ...)
current->fs = fs;
atomic_inc(&fs->count);
- exit_namespace(current);
exit_task_namespaces(current);
- current->namespace = init_task.namespace;
current->nsproxy = init_task.nsproxy;
- get_namespace(current->namespace);
get_task_namespaces(current);
exit_files(current);
@@ -924,7 +920,6 @@ fastcall NORET_TYPE void do_exit(long co
exit_sem(tsk);
__exit_files(tsk);
__exit_fs(tsk);
- exit_namespace(tsk);
exit_task_namespaces(tsk);
exit_thread();
cpuset_exit(tsk);
diff --git a/kernel/fork.c b/kernel/fork.c
index 60303c3..ddab7e7 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1063,11 +1063,9 @@ static task_t *copy_process(unsigned lon
goto bad_fork_cleanup_mm;
if ((retval = copy_namespaces(clone_flags, p)))
goto bad_fork_cleanup_keys;
- if ((retval = copy_namespace(clone_flags, p)))
- goto bad_fork_cleanup_namespaces;
retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
if (retval)
- goto bad_fork_cleanup_namespace;
+ goto bad_fork_cleanup_namespaces;
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
/*
@@ -1154,7 +1152,7 @@ static task_t *copy_process(unsigned lon
spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
retval = -ERESTARTNOINTR;
- goto bad_fork_cleanup_namespace;
+ goto bad_fork_cleanup_namespaces;
}
if (clone_flags & CLONE_THREAD) {
@@ -1167,7 +1165,7 @@ static task_t *copy_process(unsigned lon
spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
retval = -EAGAIN;
- goto bad_fork_cleanup_namespace;
+ goto bad_fork_cleanup_namespaces;
}
p->group_leader = current->group_leader;
@@ -1219,8 +1217,6 @@ static task_t *copy_process(unsigned lon
proc_fork_connector(p);
return p;
-bad_fork_cleanup_namespace:
- exit_namespace(p);
bad_fork_cleanup_namespaces:
exit_task_namespaces(p);
bad_fork_cleanup_keys:
@@ -1472,10 +1468,9 @@ static int unshare_fs(unsigned long unsh
*/
static int unshare_namespace(unsigned long unshare_flags, struct namespace **new_nsp, struct fs_struct *new_fs)
{
- struct namespace *ns = current->namespace;
+ struct namespace *ns = current->nsproxy->namespace;
- if ((unshare_flags & CLONE_NEWNS) &&
- (ns && atomic_read(&ns->count) > 1)) {
+ if ((unshare_flags & CLONE_NEWNS) && ns) {
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -1608,8 +1603,8 @@ asmlinkage long sys_unshare(unsigned lon
}
if (new_ns) {
- ns = current->namespace;
- current->namespace = new_ns;
+ ns = current->nsproxy->namespace;
+ current->nsproxy->namespace = new_ns;
new_ns = ns;
}
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 6f53df1..4103f58 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -1,18 +1,19 @@
/*
* Copyright (C) 2006 IBM Corporation
- *
- * Author: Serge Hallyn <serue@xxxxxxxxxx>
- *
+ *
+ * Author: Serge Hallyn <serue@xxxxxxxxxx>
+ *
* 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/compile.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/nsproxy.h>
+#include <linux/namespace.h>
static inline void get_nsproxy(struct nsproxy *ns)
{
@@ -53,6 +54,11 @@ struct nsproxy *dup_namespaces(struct ns
{
struct nsproxy *ns = clone_namespaces(orig);
+ if (ns) {
+ if (ns->namespace)
+ get_namespace(ns->namespace);
+ }
+
return ns;
}
@@ -63,16 +69,40 @@ struct nsproxy *dup_namespaces(struct ns
int copy_namespaces(int flags, struct task_struct *tsk)
{
struct nsproxy *old_ns = tsk->nsproxy;
+ struct nsproxy *new_ns;
+ int err = 0;
if (!old_ns)
return 0;
get_nsproxy(old_ns);
- return 0;
+ if (!(flags & CLONE_NEWNS))
+ return 0;
+
+ new_ns = clone_namespaces(old_ns);
+ if (!new_ns) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ tsk->nsproxy = new_ns;
+
+ err = copy_namespace(flags, tsk);
+ if (err) {
+ tsk->nsproxy = old_ns;
+ put_nsproxy(new_ns);
+ goto out;
+ }
+
+out:
+ put_nsproxy(old_ns);
+ return err;
}
void free_nsproxy(struct nsproxy *ns)
{
+ if (ns->namespace)
+ put_namespace(ns->namespace);
kfree(ns);
}
--
1.1.6
-
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