[patch 01/14] cgroup: dont call vfs_mkdir

From: Miklos Szeredi
Date: Tue Jul 22 2008 - 18:13:47 EST


From: Miklos Szeredi <mszeredi@xxxxxxx>

cgroup_clone() calls vfs_mkdir() to create a directory in the cgroup
filesystem. Replace with explicit call to cgroup_mkdir() and
fsnotify_mkdir().

This is equivalent, except that the following functions are not called
before cgroup_mkdir():

- may_create()
- security_inode_mkdir()
- DQUOT_INIT()

Permission to clone the cgroup has already been checked in
copy_namespaces() (requiring CAP_SYS_ADMIN). Additional file system
related capability checks are inappropriate and confusing.

The quota check is unnecessary, as quotas don't make any sense for
this filesystem.

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
CC: Paul Menage <menage@xxxxxxxxxx>
---
kernel/cgroup.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6/kernel/cgroup.c
===================================================================
--- linux-2.6.orig/kernel/cgroup.c 2008-07-23 00:10:13.000000000 +0200
+++ linux-2.6/kernel/cgroup.c 2008-07-23 00:10:20.000000000 +0200
@@ -25,6 +25,7 @@
#include <linux/cgroup.h>
#include <linux/errno.h>
#include <linux/fs.h>
+#include <linux/fsnotify.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
@@ -2928,7 +2929,9 @@ int cgroup_clone(struct task_struct *tsk
}

/* Create the cgroup directory, which also creates the cgroup */
- ret = vfs_mkdir(inode, dentry, S_IFDIR | 0755);
+ ret = cgroup_mkdir(inode, dentry, S_IFDIR);
+ if (!ret)
+ fsnotify_mkdir(inode, dentry);
child = __d_cgrp(dentry);
dput(dentry);
if (ret) {

--
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