Re: [PATCH 0/3] smb/client(cifs): prepare for locking changes.

[Christian Brauner]

On Mon, Sep 28, 2026 at 11:25:01AM +1000, NeilBrown wrote:
> I am working on changes to directory locking.  The medium term goal is
> to lift d_alloc_parallel() locking above i_rwsem, so d_alloc_paralle()
> can be run unlocked, and consequently cannot be called when ->i_rwsem is
> held.
> 
> The requires:
>  1/ that d_alloc_parallel() not be called while i_rwsem is held.  cifs
>     does this in a couple of places.  A new interface d_alloc_trylock()
>     is now available and can be used instead.
> 
>  2/ a dentry must not be d_drop()ed while an operation is ongoing, as an
>     unlocked d_alloc_parallel() would then be able to create a new
>     dentry with the same name.  In particular d_rehash() must be phased
>     out as it won't be safe.  This particularly affects the mechanism to
>     block lookups/revalidates while an unlink/rename is happening.  The
>     mechanism is changed to use one similar to how NFS addresses this
>     needed, though using the new LOOKUP_PRIVATE flag.
> 
> The patches depend on patches recently added to the vfs tree.  I would
> prefer these land in that tree too with an Acked-by or similar from cifs
> maintainers.

Can do, will need an Ack.