Re: [RFC PATCH] mountinfo: show only reachable mounts

[Jan Blunck <jblunck@suse.de>]

On Thu, Mar 13, Miklos Szeredi wrote:

> But I'm an idiot.  This is a much simpler and faster implementation
> that uses is_subdir(), which essentially does what you suggested:
> 
> /*
>  * Return true if 'path' is reachable from 'root'
>  */
> static bool is_path_reachable(const struct path *path, const struct path *root)
> {
> 	struct dentry *dentry = path->dentry;
> 	struct vfsmount *mnt = path->mnt;
> 	bool res = false;
> 
> 	spin_lock(&vfsmount_lock);
> 	while (mnt != root->mnt && mnt->mnt_parent != mnt) {
> 		dentry = mnt->mnt_mountpoint;
> 		mnt = mnt->mnt_parent;
> 	}
> 	if (mnt == root->mnt && is_subdir(dentry, root->dentry))
> 		res = true;
> 	spin_unlock(&vfsmount_lock);
> 
> 	return res;
> }

Very well.

BTW, I have a patch rotting in my quilt stack to remove
lives_below_in_same_fs() since is_subdir() provides the same
functionality.

Cheers,
Jan