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From: Amir Goldstein <amir73il@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <christian.brauner@ubuntu.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>
Subject: Re: [RFC][PATCH] fanotify: allow setting FAN_CREATE in mount mark mask
Date: Tue, 30 Mar 2021 15:20:37 +0300	[thread overview]
Message-ID: <CAOQ4uxiSqG24sTnNQzjPEtRoUQvRus0ahO_se=Oo9pTU3yfGRQ@mail.gmail.com> (raw)
In-Reply-To: <20210328155624.930558-1-amir73il@gmail.com>

On Sun, Mar 28, 2021 at 6:56 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> Add a high level hook fsnotify_path_create() which is called from
> syscall context where mount context is available, so that FAN_CREATE
> event can be added to a mount mark mask.
>
> This high level hook is called in addition to fsnotify_create(),
> fsnotify_mkdir() and fsnotify_link() hooks in vfs helpers where the mount
> context is not available.
>
> In the context where fsnotify_path_create() will be called, a dentry flag
> flag is set on the new dentry the suppress the FS_CREATE event in the vfs
> level hooks.
>
> This functionality was requested by Christian Brauner to replace
> recursive inotify watches for detecting when some path was created under
> an idmapped mount without having to monitor FAN_CREATE events in the
> entire filesystem.
>
> In combination with more changes to allow unprivileged fanotify listener
> to watch an idmapped mount, this functionality would be usable also by
> nested container managers.
>
> Link: https://lore.kernel.org/linux-fsdevel/20210318143140.jxycfn3fpqntq34z@wittgenstein/
> Cc: Christian Brauner <christian.brauner@ubuntu.com>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>
> Jan,
>
> After trying several different approaches, I finally realized that
> making FAN_CREATE available for mount marks is not that hard and it could
> be very useful IMO.
>
> Adding support for other "inode events" with mount mark, such as
> FAN_ATTRIB, FAN_DELETE, FAN_MOVE may also be possible, but adding support
> for FAN_CREATE was really easy due to the fact that all call sites are
> already surrounded by filename_creat()/done_path_create() calls.
>

FWIW, adding support for FAN_DELETE and FAN_MOVE_SELF was not
so hard. The move event at least will also be needed for the use case
where watching when a negative path is instantiated.

https://github.com/amir73il/linux/commits/fsnotify_path_hooks

Thanks,
Amir.

      parent reply	other threads:[~2021-03-30 12:21 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-28 15:56 [RFC][PATCH] fanotify: allow setting FAN_CREATE in mount mark mask Amir Goldstein
2021-03-30  7:31 ` Christian Brauner
2021-03-30  9:31   ` Amir Goldstein
2021-03-30 16:24     ` Amir Goldstein
2021-03-31 10:08       ` Christian Brauner
2021-03-31 10:57         ` Amir Goldstein
2021-04-08 11:44         ` open_by_handle_at() in userns Amir Goldstein
2021-04-08 12:55           ` Christian Brauner
2021-04-08 14:15             ` J. Bruce Fields
2021-04-08 15:54               ` Amir Goldstein
2021-04-08 16:08                 ` J. Bruce Fields
2021-04-08 16:48                   ` Frank Filz
2021-04-08 15:34             ` Amir Goldstein
2021-04-08 15:41               ` Christian Brauner
2021-03-30 12:12 ` [RFC][PATCH] fanotify: allow setting FAN_CREATE in mount mark mask Christian Brauner
2021-03-30 12:33   ` Amir Goldstein
2021-03-30 12:53     ` Christian Brauner
2021-03-30 12:55       ` Christian Brauner
2021-03-30 13:54       ` Amir Goldstein
2021-03-30 14:17         ` Christian Brauner
2021-03-30 14:56           ` Amir Goldstein
2021-03-31  9:46             ` Christian Brauner
2021-03-31 11:29               ` Amir Goldstein
2021-03-31 12:17                 ` Christian Brauner
2021-03-31 12:59                   ` Amir Goldstein
2021-03-31 12:54                 ` Jan Kara
2021-03-31 14:06                   ` Amir Goldstein
2021-03-31 20:59                     ` fsnotify path hooks Amir Goldstein
2021-04-01 10:29                       ` Jan Kara
2021-04-01 14:18                         ` Amir Goldstein
2021-04-02  8:20                           ` Amir Goldstein
2021-04-04 10:27                             ` LSM and setxattr helpers Amir Goldstein
2021-04-05 12:23                               ` Christian Brauner
2021-04-05 14:47                               ` Mimi Zohar
2021-04-06 15:43                                 ` Amir Goldstein
2021-04-05 16:18                               ` Casey Schaufler
2021-04-06  8:35                           ` fsnotify path hooks Jan Kara
2021-04-06 18:49                           ` Amir Goldstein
2021-04-08 12:52                             ` Jan Kara
2021-04-08 15:11                               ` Amir Goldstein
2021-04-09 10:08                                 ` Jan Kara
2021-04-09 10:45                                   ` Christian Brauner
2021-04-20  6:01                                     ` Amir Goldstein
2021-04-20 11:41                                       ` Christian Brauner
2021-04-20 11:58                                         ` Amir Goldstein
2021-04-20 13:38                                         ` Christian Brauner
2021-04-09 13:22                                   ` Amir Goldstein
2021-04-09 14:30                                     ` Al Viro
2021-04-09 14:39                                       ` Christian Brauner
2021-04-09 14:46                                         ` Al Viro
2021-04-09 15:20                                           ` Christian Brauner
2021-04-09 16:06                                       ` Amir Goldstein
2021-04-09 16:09                                         ` Amir Goldstein
2021-04-18 18:51                                   ` Amir Goldstein
2021-04-19  8:08                                     ` Amir Goldstein
2021-04-19 16:41                                 ` Amir Goldstein
2021-04-19 17:02                                   ` Al Viro
2021-04-19 22:04                                     ` Amir Goldstein
2021-04-20  7:53                                       ` Amir Goldstein
2021-03-31 13:06                 ` [RFC][PATCH] fanotify: allow setting FAN_CREATE in mount mark mask J. Bruce Fields
2021-03-30 12:20 ` Amir Goldstein [this message]

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