The patch titled
Containers: add container_clone() interface
has been added to the -mm tree. Its filename is
containersv10-add-container_clone-interface.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Containers: add container_clone() interface
From: Paul Menage <[EMAIL PROTECTED]>
This patch adds support for container_clone(), a speculative interface to
creating new containers intended to be used for systems such as namespace
unsharing.
Signed-off-by: Paul Menage <[EMAIL PROTECTED]>
Cc: "Serge E. Hallyn" <[EMAIL PROTECTED]>
Cc: "Eric W. Biederman" <[EMAIL PROTECTED]>
Cc: Dave Hansen <[EMAIL PROTECTED]>
Cc: Balbir Singh <[EMAIL PROTECTED]>
Cc: Paul Jackson <[EMAIL PROTECTED]>
Cc: Kirill Korotaev <[EMAIL PROTECTED]>
Cc: Herbert Poetzl <[EMAIL PROTECTED]>
Cc: Srivatsa Vaddagiri <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
include/linux/container.h | 2
kernel/container.c | 123 ++++++++++++++++++++++++++++++++++++
2 files changed, 125 insertions(+)
diff -puN include/linux/container.h~containersv10-add-container_clone-interface
include/linux/container.h
--- a/include/linux/container.h~containersv10-add-container_clone-interface
+++ a/include/linux/container.h
@@ -195,6 +195,8 @@ static inline struct container* task_con
int container_path(const struct container *cont, char *buf, int buflen);
+int container_clone(struct task_struct *tsk, struct container_subsys *ss);
+
#else /* !CONFIG_CONTAINERS */
static inline int container_init_early(void) { return 0; }
diff -puN kernel/container.c~containersv10-add-container_clone-interface
kernel/container.c
--- a/kernel/container.c~containersv10-add-container_clone-interface
+++ a/kernel/container.c
@@ -1602,3 +1602,126 @@ void container_exit(struct task_struct *
tsk->containers = init_task.containers;
task_unlock(tsk);
}
+
+static atomic_t namecnt;
+static void get_unused_name(char *buf)
+{
+ sprintf(buf, "node%d", atomic_inc_return(&namecnt));
+}
+
+/**
+ * container_clone - duplicate the current container in the hierarchy
+ * that the given subsystem is attached to, and move this task into
+ * the new child
+ */
+int container_clone(struct task_struct *tsk, struct container_subsys *subsys)
+{
+ struct dentry *dentry;
+ int ret = 0;
+ char nodename[32];
+ struct container *parent, *child;
+ struct inode *inode;
+ struct css_group *cg;
+ struct containerfs_root *root;
+
+ /* We shouldn't be called by an unregistered subsystem */
+ BUG_ON(!subsys->active);
+
+ /* First figure out what hierarchy and container we're dealing
+ * with, and pin them so we can drop container_mutex */
+ mutex_lock(&container_mutex);
+ again:
+ root = subsys->root;
+ if (root == &rootnode) {
+ printk(KERN_INFO
+ "Not cloning container for unused subsystem %s\n",
+ subsys->name);
+ mutex_unlock(&container_mutex);
+ return 0;
+ }
+ cg = &tsk->containers;
+ parent = task_container(tsk, subsys->subsys_id);
+ /* Pin the hierarchy */
+ atomic_inc(&parent->root->sb->s_active);
+
+ mutex_unlock(&container_mutex);
+
+ /* Now do the VFS work to create a container */
+ get_unused_name(nodename);
+ inode = parent->dentry->d_inode;
+
+ /* Hold the parent directory mutex across this operation to
+ * stop anyone else deleting the new container */
+ mutex_lock(&inode->i_mutex);
+ dentry = container_get_dentry(parent->dentry, nodename);
+ if (IS_ERR(dentry)) {
+ printk(KERN_INFO
+ "Couldn't allocate dentry for %s: %ld\n", nodename,
+ PTR_ERR(dentry));
+ ret = PTR_ERR(dentry);
+ goto out_release;
+ }
+
+ /* Create the container directory, which also creates the container */
+ ret = vfs_mkdir(inode, dentry, S_IFDIR | 0755);
+ child = __d_cont(dentry);
+ dput(dentry);
+ if (ret) {
+ printk(KERN_INFO
+ "Failed to create container %s: %d\n", nodename,
+ ret);
+ goto out_release;
+ }
+
+ if (!child) {
+ printk(KERN_INFO
+ "Couldn't find new container %s\n", nodename);
+ ret = -ENOMEM;
+ goto out_release;
+ }
+
+ /* The container now exists. Retake container_mutex and check
+ * that we're still in the same state that we thought we
+ * were. */
+ mutex_lock(&container_mutex);
+ if ((root != subsys->root) ||
+ (parent != task_container(tsk, subsys->subsys_id))) {
+ /* Aargh, we raced ... */
+ mutex_unlock(&inode->i_mutex);
+
+ deactivate_super(parent->root->sb);
+ /* The container is still accessible in the VFS, but
+ * we're not going to try to rmdir() it at this
+ * point. */
+ printk(KERN_INFO
+ "Race in container_clone() - leaking container %s\n",
+ nodename);
+ goto again;
+ }
+
+ /* All seems fine. Finish by moving the task into the new container */
+ ret = attach_task(child, tsk);
+ mutex_unlock(&container_mutex);
+
+ out_release:
+ mutex_unlock(&inode->i_mutex);
+ deactivate_super(parent->root->sb);
+ return ret;
+}
+
+/* See if "cont" is a descendant of the current task's container in
+ * the appropriate hierarchy */
+
+int container_is_descendant(const struct container *cont)
+{
+ int ret;
+ struct container *target;
+ int subsys_id;
+ get_first_subsys(cont, NULL, &subsys_id);
+ target = task_container(current, subsys_id);
+ while (cont != target && cont!= cont->top_container) {
+ cont = cont->parent;
+ }
+ ret = (cont == target);
+ return ret;
+}
_
Patches currently in -mm which might be from [EMAIL PROTECTED] are
reduce-cpusetc-write_lock_irq-to-read_lock.patch
reduce-cpusetc-write_lock_irq-to-read_lock-fix.patch
containersv10-basic-container-framework.patch
containersv10-basic-container-framework-fix.patch
containersv10-example-cpu-accounting-subsystem.patch
containersv10-example-cpu-accounting-subsystem-fix.patch
containersv10-add-tasks-file-interface.patch
containersv10-add-tasks-file-interface-fix.patch
containersv10-add-fork-exit-hooks.patch
containersv10-add-fork-exit-hooks-fix.patch
containersv10-add-container_clone-interface.patch
containersv10-add-container_clone-interface-fix.patch
containersv10-add-procfs-interface.patch
containersv10-add-procfs-interface-fix.patch
containersv10-make-cpusets-a-client-of-containers.patch
containersv10-share-css_group-arrays-between-tasks-with-same-container-memberships.patch
containersv10-share-css_group-arrays-between-tasks-with-same-container-memberships-fix.patch
containersv10-simple-debug-info-subsystem.patch
containersv10-simple-debug-info-subsystem-fix.patch
containersv10-support-for-automatic-userspace-release-agents.patch
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