Re: [PATCH] fs: don't block i_writecount during exec

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2024-05-31 at 08:40 -0700, Linus Torvalds wrote:
> On Fri, 31 May 2024 at 06:05, Christian Brauner <brauner@kernel.org>
> wrote:
> > 
> > Back in 2021 we already discussed removing deny_write_access() for
> > executables. Back then I was hesistant because I thought that this
> > might
> > cause issues in userspace. But even back then I had started taking
> > some
> > notes on what could potentially depend on this and I didn't come up
> > with
> > a lot so I've changed my mind and I would like to try this.
> 
> Ack. Let's try it and see if anybody notices. Judging by past
> performance, nobody will, but...
> 
> I still think we should strive to remove the underlying i_writecount
> entirely, but yes, even if we're eventually able to do that, it
> should
> be done in small steps, and this is the obvious first one.
> 
> 

FWIW: file leases also use i_writecount and i_readcount(...see
check_conflicting_open()), but they don't rely on the semantics for
blocking writes. They're just interested in whether the inode is open
for read or write anywhere.
-- 
Jeff Layton <jlayton@kernel.org>