On Thu, Mar 1, 2012 at 2:17 PM, Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:
>
> -static void cgroup_clear_directory(struct dentry *dentry)
> +static void cgroup_clear_directory(struct dentry *dentry, bool remove_all,
> + unsigned long removed_bits)
> {
> - struct list_head *node;
> + LIST_HEAD(head);
> + struct dentry *d, *node;
>
> BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
> +
> 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);
> + list_for_each_entry_safe(d, node, &dentry->d_subdirs, d_u.d_child) {
> + struct cftype *cft = d->d_fsdata;
> +
> + if (!remove_all && cft->subsys &&
> + !test_bit(cft->subsys->subsys_id, &removed_bits))
> + continue;
>
> spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
> - list_del_init(node);
> + list_move(&d->d_u.d_child, &head);
> if (d->d_inode) {
> /* This should never be called on a cgroup
> * directory with child cgroups */
> BUG_ON(d->d_inode->i_mode & S_IFDIR);
> dget_dlock(d);
> - spin_unlock(&d->d_lock);
> - spin_unlock(&dentry->d_lock);
> + }
> + spin_unlock(&d->d_lock);
> + }
> + spin_unlock(&dentry->d_lock);
> +
Safe to process isolated entries without dentry->d_lock held?
-hd
> + list_for_each_entry_safe(d, node, &head, d_u.d_child) {
> + spin_lock(&d->d_lock);
> + list_del_init(&d->d_u.d_child);
> + spin_unlock(&d->d_lock);
> + if (d->d_inode) {
> d_delete(d);
> simple_unlink(dentry->d_inode, d);
> dput(d);
> - spin_lock(&dentry->d_lock);
> - } else
> - spin_unlock(&d->d_lock);
> - node = dentry->d_subdirs.next;
> + }
> }
> - spin_unlock(&dentry->d_lock);
> }
>
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