Re: [PATCH v2] fs/dcache.c: avoid soft-lockup in dput()

From: Al Viro
Date: Fri Sep 16 2016 - 08:10:46 EST

On Fri, Sep 16, 2016 at 01:19:19PM +0530, Vaishali Thakkar wrote:

> Hi,
> Just a question regarding this change. As after this change
> dput() is sleepable, is it still safe to use if under the
> spinlock in the function d_prune_aliases?

It has always been sleepable and it wouldn't have been safe to use
under spinlocks. Which d_prune_aliases() does not do - __dentry_kill()
is called with dentry, its parent and its inode (if present) all locked and
it drops all those locks before returning.