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References: <20210426184201.4177978-1-krisman@collabora.com> <20210426184201.4177978-13-krisman@collabora.com>
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From:   Amir Goldstein <amir73il@gmail.com>
Date:   Tue, 27 Apr 2021 10:25:14 +0300
Message-ID: <CAOQ4uxhhyZhEwg6aiNVYc4Nbxg4PBhTtcgYE0Vqm8iONXDqg=Q@mail.gmail.com>
Subject: Re: [PATCH RFC 12/15] fanotify: Introduce the FAN_ERROR mark
To:     Gabriel Krisman Bertazi <krisman@collabora.com>
Cc:     Theodore Tso <tytso@mit.edu>,
        "Darrick J. Wong" <djwong@kernel.org>,
        Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.com>,
        David Howells <dhowells@redhat.com>,
        Khazhismel Kumykov <khazhy@google.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Ext4 <linux-ext4@vger.kernel.org>, kernel@collabora.com
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On Mon, Apr 26, 2021 at 9:43 PM Gabriel Krisman Bertazi
<krisman@collabora.com> wrote:
>
> The FAN_ERROR mark is used by filesystem wide monitoring tools to
> receive notifications of type FS_ERROR_EVENT, emited by filesystems when
> a problem is detected.  The error notification includes a generic error
> descriptor, an optional location record and a filesystem specific blob.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
> ---
>  fs/notify/fanotify/fanotify.c      | 48 +++++++++++++++++++----
>  fs/notify/fanotify/fanotify.h      |  8 ++++
>  fs/notify/fanotify/fanotify_user.c | 63 ++++++++++++++++++++++++++++++
>  include/linux/fanotify.h           |  9 ++++-
>  include/uapi/linux/fanotify.h      |  2 +
>  5 files changed, 120 insertions(+), 10 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 98591a8155a7..6bae23d42e5e 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -240,12 +240,14 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
>                  __func__, iter_info->report_mask, event_mask, data, data_type);
>
>         if (!fid_mode) {
> -               /* Do we have path to open a file descriptor? */
> -               if (!path)
> -                       return 0;
> -               /* Path type events are only relevant for files and dirs */
> -               if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry))
> -                       return 0;
> +               if (!fanotify_is_error_event(event_mask)) {

This open coded nested condition is not nice.
If we get as far as this, I will explain what needs to be done.
Need helpers fanotify_is_reporting_fd(), fanotify_is_reporting_fid() and
fanotify_is_reporting_dir_fid().

Thanks,
Amir.