On Tue, 21 Oct 2008, Christoph Lameter wrote: > The only way that a secure reference can be established is if the > slab page is locked. That requires a spinlock. The slab allocator > calls the get() functions while the slab lock guarantees object > existence. Then locks are dropped and reclaim actions can start with > the guarantee that the slab object will not suddenly vanish. Yes, you've made up your mind, that you want to do it this way. But it's the _wrong_ way, this "want to get a secure reference for use later" leads to madness when applied to dentries or inodes. Try for a minute to think outside this template. For example dcache_lock will protect against dentries moving to/from d_lru. So you can do this: take dcache_lock check if d_lru is non-empty take sb->s_umount free dentry release sb->s_umount release dcache_lock Yeah, locking will be more complicated in reality. Still, much less complicated than trying to do the same across two separate phases. Why can't something like that work? Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
