question on your MOUNT_REWRITE changes.

[Tigran Aivazian]

Hi Al,

The "exchange dentries" code in sys_chdir()/chroot() used to look like
this:

        tmp = current->fs->pwd;
        current->fs->pwd = dentry;
        dput(tmp);

so, I used it in my function:

void move_task_pwd(struct task *p, struct dentry *where)
{
	struct dentry *tmp;

	tmp = p->fs->pwd;
	p->fs->pwd = dget(where);
	dput(tmp);
}

(the race with namei that may be using current->fs->pwd on some other CPU
is overcome by making sure that while move_task_pwd() is called 'p'
can't be running on any CPU).

So, with your recent changes, I assume my move_task_pwd() should look
like this:

void move_task_pwd(struct task *p, struct dentry *where)
{
        struct dentry *tmp;
	struct vfsmount *tmp_mnt;    
         
	tmp_mnt = p->fs->pwdmnt;
        tmp = p->fs->pwd;
        p->fs->pwd = dget(where);
	p->fs->pwdmnt = ???? /* mntget(what?) */
        dput(tmp);
	mntput(tmp_mnt);
}

i.e. how do I get 'struct vfsmount' by given 'dentry *where'?

My guess is that I can't. Instead I should have kept 'struct file'
corresponding to 'where' and used f_vfsmnt - is this correct? (assuming
that 'where' is always a mountpoint)

Thanks for your help,

Tigran.