Btrfs: skip adding an acl attribute if we don't have to

[pandora-kernel.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a51ba74..ec64a18 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -361,12 +361,20 @@ static void __put_css_set(struct css_set *cg, int taskexit)
                struct cgroup *cgrp = link->cgrp;
                list_del(&link->cg_link_list);
                list_del(&link->cgrp_link_list);
+
+               /*
+                * We may not be holding cgroup_mutex, and if cgrp->count is
+                * dropped to 0 the cgroup can be destroyed at any time, hence
+                * rcu_read_lock is used to keep it alive.
+                */
+               rcu_read_lock();
                if (atomic_dec_and_test(&cgrp->count) &&
                    notify_on_release(cgrp)) {
                        if (taskexit)
                                set_bit(CGRP_RELEASABLE, &cgrp->flags);
                        check_for_release(cgrp);
                }
+               rcu_read_unlock();
 
                kfree(link);
        }
@@ -873,7 +881,7 @@ static void cgroup_clear_directory(struct dentry *dentry)
        spin_lock(&dentry->d_lock);
        node = dentry->d_subdirs.next;
        while (node != &dentry->d_subdirs) {
-               struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
+               struct dentry *d = list_entry(node, struct dentry, d_child);
 
                spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
                list_del_init(node);
@@ -907,7 +915,7 @@ static void cgroup_d_remove_dir(struct dentry *dentry)
        parent = dentry->d_parent;
        spin_lock(&parent->d_lock);
        spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
-       list_del_init(&dentry->d_u.d_child);
+       list_del_init(&dentry->d_child);
        spin_unlock(&dentry->d_lock);
        spin_unlock(&parent->d_lock);
        remove_dir(dentry);
@@ -1045,15 +1053,16 @@ static int cgroup_show_options(struct seq_file *seq, struct vfsmount *vfs)
 
        mutex_lock(&cgroup_mutex);
        for_each_subsys(root, ss)
-               seq_printf(seq, ",%s", ss->name);
+               seq_show_option(seq, ss->name, NULL);
        if (test_bit(ROOT_NOPREFIX, &root->flags))
                seq_puts(seq, ",noprefix");
        if (strlen(root->release_agent_path))
-               seq_printf(seq, ",release_agent=%s", root->release_agent_path);
+               seq_show_option(seq, "release_agent",
+                               root->release_agent_path);
        if (clone_children(&root->top_cgroup))
                seq_puts(seq, ",clone_children");
        if (strlen(root->name))
-               seq_printf(seq, ",name=%s", root->name);
+               seq_show_option(seq, "name", root->name);
        mutex_unlock(&cgroup_mutex);
        return 0;
 }
@@ -2021,7 +2030,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
        if (!group)
                return -ENOMEM;
        /* pre-allocate to guarantee space while iterating in rcu read-side. */
-       retval = flex_array_prealloc(group, 0, group_size - 1, GFP_KERNEL);
+       retval = flex_array_prealloc(group, 0, group_size, GFP_KERNEL);
        if (retval)
                goto out_free_group_list;
 
@@ -2636,9 +2645,7 @@ static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry,
                dentry->d_fsdata = cgrp;
                inc_nlink(parent->d_inode);
                rcu_assign_pointer(cgrp->dentry, dentry);
-               dget(dentry);
        }
-       dput(dentry);
 
        return error;
 }
@@ -2779,9 +2786,14 @@ static void cgroup_enable_task_cg_lists(void)
                 * We should check if the process is exiting, otherwise
                 * it will race with cgroup_exit() in that the list
                 * entry won't be deleted though the process has exited.
+                * Do it while holding siglock so that we don't end up
+                * racing against cgroup_exit().
                 */
+               spin_lock_irq(&p->sighand->siglock);
                if (!(p->flags & PF_EXITING) && list_empty(&p->cg_list))
                        list_add(&p->cg_list, &p->cgroups->tasks);
+               spin_unlock_irq(&p->sighand->siglock);
+
                task_unlock(p);
        } while_each_thread(g, p);
        write_unlock(&css_set_lock);
@@ -3498,6 +3510,7 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
                                      const char *buffer)
 {
        struct cgroup_event *event = NULL;
+       struct cgroup *cgrp_cfile;
        unsigned int efd, cfd;
        struct file *efile = NULL;
        struct file *cfile = NULL;
@@ -3553,6 +3566,16 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
                goto fail;
        }
 
+       /*
+        * The file to be monitored must be in the same cgroup as
+        * cgroup.event_control is.
+        */
+       cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent);
+       if (cgrp_cfile != cgrp) {
+               ret = -EINVAL;
+               goto fail;
+       }
+
        if (!event->cft->register_event || !event->cft->unregister_event) {
                ret = -EINVAL;
                goto fail;
@@ -3849,6 +3872,11 @@ static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
        struct cgroup *c_parent = dentry->d_parent->d_fsdata;
 
+       /* Do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable.
+        */
+       if (strchr(dentry->d_name.name, '\n'))
+               return -EINVAL;
+
        /* the vfs holds inode->i_mutex already */
        return cgroup_create(c_parent, dentry, mode | S_IFDIR);
 }