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From: Max Kellermann <max.kellermann@ionos.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	amir73il@gmail.com
Subject: Re: [PATCH 3/4] inotify_user: add system call inotify_add_watch_at()
Date: Mon, 18 Sep 2023 21:45:16 +0200	[thread overview]
Message-ID: <CAKPOu+9yAKCtrRZsZPFDtM6RP6Ev_-2x84WYCLf_SPHJcr3Faw@mail.gmail.com> (raw)
In-Reply-To: <20230918124050.hzbgpci42illkcec@quack3>

On Mon, Sep 18, 2023 at 2:40 PM Jan Kara <jack@suse.cz> wrote:
> Is there any problem with using fanotify for you?

Turns out fanotify is unusable for me, unfortunately.
I have been using inotify to get notifications of cgroup events, but
the cgroup filesystem appears to be unsupported by fanotify: all
attempts to use fanotify_mark() on cgroup event files fail with
ENODEV. I think that comes from fanotify_test_fsid(). Filesystems
without a fsid work just fine with inotify, but fail with fanotify.

Since fanotify lacks important features, is it really a good idea to
feature-freeze inotify?

(By the way, what was not documented is that fanotify_init() can only
be used by unprivileged processes if the FAN_REPORT_FID flag was
specified. I had to read the kernel sources to figure that out - I
have no idea why this limitation exists - the code comment in the
kernel source doesn't explain it.)

  parent reply	other threads:[~2023-09-18 19:45 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-18 12:32 [PATCH 1/4] inotify_user: pass directory fd to inotify_find_inode() Max Kellermann
2023-09-18 12:32 ` [PATCH 2/4] inotify_user: move code to do_inotify_add_watch() Max Kellermann
2023-09-18 12:32 ` [PATCH 3/4] inotify_user: add system call inotify_add_watch_at() Max Kellermann
2023-09-18 12:40   ` Jan Kara
2023-09-18 13:57     ` Max Kellermann
2023-09-18 14:23       ` Jan Kara
2023-09-18 15:28         ` Amir Goldstein
2023-09-18 18:05           ` inotify maintenance status Amir Goldstein
2023-09-19  7:16             ` Amir Goldstein
2023-09-19  9:08               ` Max Kellermann
2023-09-19 10:01                 ` Jan Kara
2023-09-19 10:42                   ` Amir Goldstein
2023-09-19 10:48                     ` Max Kellermann
2023-09-19 10:42                   ` Max Kellermann
2023-09-19 10:58                     ` Amir Goldstein
2023-09-19 11:21                       ` Max Kellermann
2023-09-19 12:21                         ` Amir Goldstein
2023-09-19 12:51                           ` Max Kellermann
2023-09-19 13:01                             ` Amir Goldstein
2023-09-19 13:11                               ` Max Kellermann
2023-09-19 13:22                                 ` Amir Goldstein
2023-09-19 13:41                                   ` Max Kellermann
2023-09-19 13:56                                     ` Amir Goldstein
2023-09-19 13:28                         ` Jan Kara
2023-09-19 13:48                           ` Max Kellermann
2023-09-19  9:26             ` Christian Brauner
2023-09-19  9:48             ` Jan Kara
2023-09-19 14:55               ` Amir Goldstein
2023-09-18 19:45     ` Max Kellermann [this message]
2023-09-18 12:32 ` [PATCH 4/4] arch: register inotify_add_watch_at Max Kellermann
2023-09-18 20:24   ` kernel test robot
2023-09-18 20:24   ` kernel test robot

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