linux-ext4 - Re: [PATCH v8 13/19] fanotify: add a helper to check for pre content events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAOQ4uxjLraeWK78d69DRTpuAWWmaPSaHmi-15hW2KRLES6M4qQ@mail.gmail.com>
Date: Wed, 20 Nov 2024 17:43:56 +0100
From: Amir Goldstein <amir73il@...il.com>
To: Jan Kara <jack@...e.cz>
Cc: Josef Bacik <josef@...icpanda.com>, kernel-team@...com, linux-fsdevel@...r.kernel.org, 
	brauner@...nel.org, torvalds@...ux-foundation.org, viro@...iv.linux.org.uk, 
	linux-xfs@...r.kernel.org, linux-btrfs@...r.kernel.org, linux-mm@...ck.org, 
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH v8 13/19] fanotify: add a helper to check for pre content events

On Wed, Nov 20, 2024 at 4:44 PM Jan Kara <jack@...e.cz> wrote:
>
> On Fri 15-11-24 10:30:26, Josef Bacik wrote:
> > From: Amir Goldstein <amir73il@...il.com>
> >
> > We want to emit events during page fault, and calling into fanotify
> > could be expensive, so add a helper to allow us to skip calling into
> > fanotify from page fault.  This will also be used to disable readahead
> > for content watched files which will be handled in a subsequent patch.
> >
> > Signed-off-by: Josef Bacik <josef@...icpanda.com>
> > Signed-off-by: Amir Goldstein <amir73il@...il.com>
> > ---
> >  include/linux/fsnotify.h | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> > index 08893429a818..d5a0d8648000 100644
> > --- a/include/linux/fsnotify.h
> > +++ b/include/linux/fsnotify.h
> > @@ -178,6 +178,11 @@ static inline void file_set_fsnotify_mode(struct file *file)
> >       }
> >  }
> >
> > +static inline bool fsnotify_file_has_pre_content_watches(struct file *file)
> > +{
> > +     return file && unlikely(FMODE_FSNOTIFY_HSM(file->f_mode));
> > +}
> > +
>
> I was pondering about this and since we are trying to make these quick
> checks more explicit, I'll probably drop this helper. Also the 'file &&'
> part looks strange (I understand page_cache_[a]sync_ra() need it but I'd
> rather handle it explicitely there).

Makes sense.

Thanks,
Amir.