Quoting matthew green <mrg@eterna.com.au>:

> there is an vfs_busy() that works on a per-mountpoint basis,
> is this what you're after?

I think it doesn't do what I want.  I have vfs_busy around the VFS_SYNC call 
and I delayed the vfs_unbusy until after I have taken the snapshot and it 
didn't make a noticeable difference, i.e. fsck phase 5 reports missing blocks 
and occasionally there's other errors.

-- 
Christian Limpach <chris@pin.lu>