From b592fcfe7f06c15ec11774b5be7ce0de3aa86e73 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 24 Jan 2007 12:35:52 -0700 Subject: sysfs: Shadow directory support The problem. When implementing a network namespace I need to be able to have multiple network devices with the same name. Currently this is a problem for /sys/class/net/*. What I want is a separate /sys/class/net directory in sysfs for each network namespace, and I want to name each of them /sys/class/net. I looked and the VFS actually allows that. All that is needed is for /sys/class/net to implement a follow link method to redirect lookups to the real directory you want. Implementing a follow link method that is sensitive to the current network namespace turns out to be 3 lines of code so it looks like a clean approach. Modifying sysfs so it doesn't get in my was is a bit trickier. I am calling the concept of multiple directories all at the same path in the filesystem shadow directories. With the directory entry really at that location the shadow master. The following patch modifies sysfs so it can handle a directory structure slightly different from the kobject tree so I can implement the shadow directories for handling /sys/class/net/. Signed-off-by: Eric W. Biederman Cc: Maneesh Soni Signed-off-by: Greg Kroah-Hartman --- include/linux/kobject.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/kobject.h') diff --git a/include/linux/kobject.h b/include/linux/kobject.h index 76538fcf2c4e..b850e0310538 100644 --- a/include/linux/kobject.h +++ b/include/linux/kobject.h @@ -74,9 +74,13 @@ extern void kobject_init(struct kobject *); extern void kobject_cleanup(struct kobject *); extern int __must_check kobject_add(struct kobject *); +extern int __must_check kobject_shadow_add(struct kobject *, struct dentry *); extern void kobject_del(struct kobject *); extern int __must_check kobject_rename(struct kobject *, const char *new_name); +extern int __must_check kobject_shadow_rename(struct kobject *kobj, + struct dentry *new_parent, + const char *new_name); extern int __must_check kobject_move(struct kobject *, struct kobject *); extern int __must_check kobject_register(struct kobject *); -- cgit v1.2.2