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Date:   Tue, 26 Oct 2021 14:06:37 +0200
From:   Jan Kara <jack@suse.cz>
To:     Amir Goldstein <amir73il@gmail.com>
Cc:     Gabriel Krisman Bertazi <krisman@collabora.com>,
        Jan Kara <jack@suse.com>,
        "Darrick J. Wong" <djwong@kernel.org>,
        Theodore Tso <tytso@mit.edu>,
        Dave Chinner <david@fromorbit.com>,
        David Howells <dhowells@redhat.com>,
        Khazhismel Kumykov <khazhy@google.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Ext4 <linux-ext4@vger.kernel.org>, kernel@collabora.com,
        Jan Kara <jack@suse.cz>
Subject: Re: [PATCH v9 24/31] fanotify: Report fid entry even for zero-length
 file_handle
Message-ID: <20211026120637.GD21228@quack2.suse.cz>
References: <20211025192746.66445-1-krisman@collabora.com>
 <20211025192746.66445-25-krisman@collabora.com>
 <CAOQ4uxhCsCPNN=Xb6Xo9VpW+rYCkMUy-1zEXO41d1D4vN74GcA@mail.gmail.com>
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On Tue 26-10-21 12:09:19, Amir Goldstein wrote:
> On Mon, Oct 25, 2021 at 10:30 PM Gabriel Krisman Bertazi
> <krisman@collabora.com> wrote:
> >
> > Non-inode errors will reported with an empty file_handle.  In
> > preparation for that, allow some events to print the FID record even if
> > there isn't any file_handle encoded
> >
> > Even though FILEID_ROOT is used internally, make zero-length file
> > handles be reported as FILEID_INVALID.
> >
> > Reviewed-by: Amir Goldstein <amir73il@gmail.com>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
> >
> > ---
> > Changes since v8:
> >   - Move fanotify_event_has_object_fh check here (jan)
> 
> Logically, this move is wrong, because after this patch,
> copy_fid_info_to_user() can theoretically be called with NULL fh in the
> existing construct of:
>   if (fanotify_event_has_object_fh(event)) {
>   ...
>     ret = copy_fid_info_to_user(fanotify_event_fsid(event),
> 
> fanotify_event_object_fh(event),
> 
> The thing that prevents this case in effect is that FAN_FS_ERROR
> is not yet wired, but I am not sure if leaving this theoretic bisect
> issue is a good idea.
> 
> Anyway, that's a very minor theoretic issue and I am sure Jan can
> decide whether to deal with it and how (no need to post v10 IMO).

Hum, correct. I guess I'll just fold this patch into patch 26. Logically
they are very close anyway.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR