Re: How to get vfsmount from inode?

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chrisat_private

* Omen Wild (Omen.Wildat_private) wrote:
> 
> Something like this?

No, cycle the whole namespace looking for mountpoint roots that match
the root of the superblock that the dentry (that you start with) is on.

More like:
> ...
> struct vfsmount *mnt = find_vfsmount(inode->i_sb->s_root);
> ...
> 
> static struct vfsmount *find_vfsmount(struct dentry *d) {
	struct dentry *root = dget(dentry->d_sb->s_root);
	struct namespace *namespace = current->namespace;
	struct list_head *head;
	struct vfsmount *mnt = NULL;

	down_read(&namespace->sem);
	list_for_each(head, &namespace->list) {
		mnt = list_entry(head, struct vfsmount, mnt_list);
		if (mnt->mnt_root == sb_root) {
			mntget(mnt);
			break;	/* this is the problem spot */
		}
	}
	up_read(&namespace->sem);
	dput(sb_root);
	return mnt;
}

It's pretty fugly, but will find the matches (well, with the 'break' only
the first match.  which is not necessarily the path the user used to get
to the dentry!).

thanks,
-chris
-- 
Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net
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