On Wed, Apr 09, 2014 at 03:30:27AM +0100, Al Viro wrote: > > When renaming or unlinking directory entries that are not mountpoints > > no additional locks are taken so no performance differences can result, > > and my benchmark reflected that. > > It also means that d_invalidate() now might trigger fs shutdown. Which > has bloody huge stack footprint, for obvious reasons. And d_invalidate() > can be called with pretty deep stack - walk into wrong dentry while > resolving a deeply nested symlink and there you go...
PS: I thought I actually replied with that point back a month or so ago, but having checked sent-mail... Looks like I had not. My deep apologies. FWIW, I think that overall this thing is a good idea, provided that we can live with semantics changes. The implementation is too optimistic, though - at the very least, we want this work done upon namespace_unlock() held back until we are not too deep in stack. task_work_add() fodder, perhaps? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
