linux-kernel - Re: [PATCH 1/3] nfsd: use __fput_sync() to avoid delayed closing of files.

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Message-ID: <20231211191117.GD1674809@ZenIV>
Date:   Mon, 11 Dec 2023 19:11:17 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     NeilBrown <neilb@...e.de>
Cc:     Chuck Lever <chuck.lever@...cle.com>,
        Christian Brauner <brauner@...nel.org>,
        Jens Axboe <axboe@...nel.dk>, Oleg Nesterov <oleg@...hat.com>,
        Jeff Layton <jlayton@...nel.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-nfs@...r.kernel.org
Subject: Re: [PATCH 1/3] nfsd: use __fput_sync() to avoid delayed closing of
 files.

On Mon, Dec 11, 2023 at 09:47:35AM +1100, NeilBrown wrote:

> Similarly would could wrap __fput_sync() is a more friendly name, but
> that would be better if we actually renamed the function.
> 
>   void fput_now(struct file *f)
>   {
>       __fput_sync(f);
>   }

It is unfriendly *precisely* because it should not be used without
a very good reason.

It may be the last opened file keeping a lazy-umounted mount alive.
It may be taking pretty much any locks, or eating a lot of stack
space.

It really isn't a general-purpose API; any "more friendly name"
is going to be NAKed for that reason alone.

Al, very much tempted to send a patch renaming that sucker to
__fput_dont_use_that_unless_you_really_know_what_you_are_doing().