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From: Karel Zak <kzak@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: David Howells <dhowells@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	dray@redhat.com, Miklos Szeredi <mszeredi@redhat.com>,
	Steven Whitehouse <swhiteho@redhat.com>,
	Jeff Layton <jlayton@redhat.com>, Ian Kent <raven@themaw.net>,
	andres@anarazel.de,
	Christian Brauner <christian.brauner@ubuntu.com>,
	keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
Date: Tue, 31 Mar 2020 09:21:01 +0000	[thread overview]
Message-ID: <20200331092101.fnipaxqewol2hzd2@ws.net.home> (raw)
In-Reply-To: <CAJfpegvZ_qtdGcP4bNQyYt1BbgF9HdaDRsmD43a-Muxgki+wTw@mail.gmail.com>

On Mon, Mar 30, 2020 at 10:28:56PM +0200, Miklos Szeredi wrote:
> All this could be solved with a string key/value representation of the
> same data, with minimal performance loss on encoding/parsing.  The
> proposed fs interface[1] is one example of that, but I could also
> imagine a syscall based one too.

Yes, key/value is possible solution. The question is if we really 
need to add extra /sys-like filesystem to get key/value ;-) I can 
imagine key/value from FD based interface without open/read/close for
each attribute,

    fd = open("/mnt", O_PATH);
    fsinfo(fd, "propagation", buf, sizeof(buf));
    fsinfo(fd, "fstype", buf, sizeof(buf));
    close(fd);

why I need /mountfs/<id>/propagation and /mountfs/<id>/fstype to get
the same? It sounds like over-engineering without any extra bonus.

Anyway, if we have FD based interfaces like fsopen(), fsmount(),
open_tree() and move_mount() then it sounds strange that you cannot
use the FD to ask kernel for the mount node attributes and you need 
to open and read another /sys-like files. 

IMHO it would be nice that after open(/mnt, O_PATH) I can do whatever
with the mount point (umount, move, reconfigure, query, etc.). Please,
try to keep it simple and consistent ;-)

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

WARNING: multiple messages have this Message-ID (diff)
From: Karel Zak <kzak@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: David Howells <dhowells@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	dray@redhat.com, Miklos Szeredi <mszeredi@redhat.com>,
	Steven Whitehouse <swhiteho@redhat.com>,
	Jeff Layton <jlayton@redhat.com>, Ian Kent <raven@themaw.net>,
	andres@anarazel.de,
	Christian Brauner <christian.brauner@ubuntu.com>,
	keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: Upcoming: Notifications, FS notifications and fsinfo()
Date: Tue, 31 Mar 2020 11:21:01 +0200	[thread overview]
Message-ID: <20200331092101.fnipaxqewol2hzd2@ws.net.home> (raw)
In-Reply-To: <CAJfpegvZ_qtdGcP4bNQyYt1BbgF9HdaDRsmD43a-Muxgki+wTw@mail.gmail.com>

On Mon, Mar 30, 2020 at 10:28:56PM +0200, Miklos Szeredi wrote:
> All this could be solved with a string key/value representation of the
> same data, with minimal performance loss on encoding/parsing.  The
> proposed fs interface[1] is one example of that, but I could also
> imagine a syscall based one too.

Yes, key/value is possible solution. The question is if we really 
need to add extra /sys-like filesystem to get key/value ;-) I can 
imagine key/value from FD based interface without open/read/close for
each attribute,

    fd = open("/mnt", O_PATH);
    fsinfo(fd, "propagation", buf, sizeof(buf));
    fsinfo(fd, "fstype", buf, sizeof(buf));
    close(fd);

why I need /mountfs/<id>/propagation and /mountfs/<id>/fstype to get
the same? It sounds like over-engineering without any extra bonus.

Anyway, if we have FD based interfaces like fsopen(), fsmount(),
open_tree() and move_mount() then it sounds strange that you cannot
use the FD to ask kernel for the mount node attributes and you need 
to open and read another /sys-like files. 

IMHO it would be nice that after open(/mnt, O_PATH) I can do whatever
with the mount point (umount, move, reconfigure, query, etc.). Please,
try to keep it simple and consistent ;-)

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com


  reply	other threads:[~2020-03-31  9:21 UTC|newest]

Thread overview: 199+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-30 13:58 Upcoming: Notifications, FS notifications and fsinfo() David Howells
2020-03-30 13:58 ` David Howells
2020-03-30 14:31 ` [GIT PULL] General notification queue and key notifications David Howells
2020-03-30 14:31   ` David Howells
2020-03-31  6:51   ` Stephen Rothwell
2020-03-31  6:51     ` Stephen Rothwell
2020-06-02 15:55   ` David Howells
2020-06-02 15:55     ` David Howells
2020-06-03  2:15     ` Ian Kent
2020-06-03  2:15       ` Ian Kent
2020-06-08  0:49       ` Ian Kent
2020-06-08  0:49         ` Ian Kent
2020-06-10  9:56     ` Christian Brauner
2020-06-10  9:56       ` Christian Brauner
2020-06-10 11:12     ` Karel Zak
2020-06-10 11:12       ` Karel Zak
2020-06-12 21:32       ` Linus Torvalds
2020-06-12 21:32         ` Linus Torvalds
2020-06-12 22:01       ` Linus Torvalds
2020-06-12 22:01         ` Linus Torvalds
2020-06-13 13:04       ` David Howells
2020-06-13 13:04         ` David Howells
2020-06-13 16:47         ` Linus Torvalds
2020-06-13 16:47           ` Linus Torvalds
2020-06-13 17:03           ` Linus Torvalds
2020-06-13 17:03             ` Linus Torvalds
2020-06-13 19:22         ` Miklos Szeredi
2020-06-13 19:22           ` Miklos Szeredi
2020-06-13 13:24       ` David Howells
2020-06-13 13:24         ` David Howells
2020-06-13 18:00     ` pr-tracker-bot
2020-06-13 18:00       ` pr-tracker-bot
2020-06-17  1:15     ` Williams, Dan J
2020-06-17  1:15       ` Williams, Dan J
2020-06-17  1:15       ` Williams, Dan J
2020-06-23 23:38       ` Dan Williams
2020-06-23 23:38         ` Dan Williams
2020-06-23 23:38         ` Dan Williams
2020-06-24  0:55       ` David Howells
2020-06-24  0:55         ` David Howells
2020-06-24  0:55         ` David Howells
2020-06-24  1:03         ` Dan Williams
2020-06-24  1:03           ` Dan Williams
2020-06-24  1:03           ` Dan Williams
2020-06-24  1:17         ` David Howells
2020-06-24  1:17           ` David Howells
2020-06-24  1:17           ` David Howells
2020-03-30 14:36 ` [GIT PULL] Mount and superblock notifications David Howells
2020-03-30 14:36   ` David Howells
2020-04-04 21:13   ` Linus Torvalds
2020-04-04 21:13     ` Linus Torvalds
2020-04-05 22:52     ` Andres Freund
2020-04-05 22:52       ` Andres Freund
2020-03-30 14:43 ` [GIT PULL] fsinfo: Filesystem information query David Howells
2020-03-30 14:43   ` David Howells
2020-03-30 20:28 ` Upcoming: Notifications, FS notifications and fsinfo() Miklos Szeredi
2020-03-30 20:28   ` Miklos Szeredi
2020-03-31  9:21   ` Karel Zak [this message]
2020-03-31  9:21     ` Karel Zak
2020-03-30 21:17 ` Christian Brauner
2020-03-30 21:17   ` Christian Brauner
2020-03-31  5:11   ` Miklos Szeredi
2020-03-31  5:11     ` Miklos Szeredi
2020-03-31  8:15     ` Christian Brauner
2020-03-31  8:15       ` Christian Brauner
2020-03-31  8:34       ` Miklos Szeredi
2020-03-31  8:34         ` Miklos Szeredi
2020-03-31  8:34     ` Karel Zak
2020-03-31  8:34       ` Karel Zak
2020-03-31  8:56       ` Miklos Szeredi
2020-03-31  8:56         ` Miklos Szeredi
2020-03-31  9:49         ` Karel Zak
2020-03-31  9:49           ` Karel Zak
2020-03-31 12:25         ` Lennart Poettering
2020-03-31 12:25           ` Lennart Poettering
2020-03-31 15:10           ` Miklos Szeredi
2020-03-31 15:10             ` Miklos Szeredi
2020-03-31 15:24             ` Lennart Poettering
2020-03-31 15:24               ` Lennart Poettering
2020-03-31 21:56         ` David Howells
2020-03-31 21:56           ` David Howells
2020-03-31 21:54     ` David Howells
2020-03-31 21:54       ` David Howells
2020-04-01  8:43       ` Karel Zak
2020-04-01  8:43         ` Karel Zak
2020-03-31  7:22   ` Lennart Poettering
2020-03-31  7:22     ` Lennart Poettering
2020-03-31 17:31 ` David Howells
2020-03-31 17:31   ` David Howells
2020-03-31 19:42   ` Miklos Szeredi
2020-03-31 19:42     ` Miklos Szeredi
2020-03-31 19:47   ` David Howells
2020-03-31 19:47     ` David Howells
2020-03-31 21:14   ` David Howells
2020-03-31 21:14     ` David Howells
2020-03-31 21:23   ` David Howells
2020-03-31 21:23     ` David Howells
2020-03-31 21:52 ` David Howells
2020-03-31 21:52   ` David Howells
2020-04-01  9:04   ` Karel Zak
2020-04-01  9:04     ` Karel Zak
2020-04-01 13:34     ` Miklos Szeredi
2020-04-01 13:34       ` Miklos Szeredi
2020-04-01 13:55     ` David Howells
2020-04-01 13:55       ` David Howells
2020-04-01 13:58     ` David Howells
2020-04-01 13:58       ` David Howells
2020-04-01 15:25       ` Miklos Szeredi
2020-04-01 15:25         ` Miklos Szeredi
2020-04-03  9:11         ` Karel Zak
2020-04-03  9:11           ` Karel Zak
2020-04-01 16:01       ` David Howells
2020-04-01 16:01         ` David Howells
2020-04-01 16:30         ` Miklos Szeredi
2020-04-01 16:30           ` Miklos Szeredi
2020-04-02 15:22         ` David Howells
2020-04-02 15:22           ` David Howells
2020-04-02 15:24           ` Miklos Szeredi
2020-04-02 15:24             ` Miklos Szeredi
2020-04-02 15:42           ` David Howells
2020-04-02 15:42             ` David Howells
2020-04-02 15:24         ` David Howells
2020-04-02 15:24           ` David Howells
2020-04-01 14:41   ` Lennart Poettering
2020-04-01 14:41     ` Lennart Poettering
2020-04-01 15:33     ` Miklos Szeredi
2020-04-01 15:33       ` Miklos Szeredi
2020-04-01 16:06     ` David Howells
2020-04-01 16:06       ` David Howells
2020-04-01 16:40       ` Miklos Szeredi
2020-04-01 16:40         ` Miklos Szeredi
2020-04-02  2:52         ` Ian Kent
2020-04-02  2:52           ` Ian Kent
2020-04-02 13:52           ` Miklos Szeredi
2020-04-02 13:52             ` Miklos Szeredi
2020-04-02 14:36             ` Lennart Poettering
2020-04-02 14:36               ` Lennart Poettering
2020-04-02 15:22               ` Miklos Szeredi
2020-04-02 15:22                 ` Miklos Szeredi
2020-04-02 15:28                 ` Lennart Poettering
2020-04-02 15:28                   ` Lennart Poettering
2020-04-02 15:35                   ` Miklos Szeredi
2020-04-02 15:35                     ` Miklos Szeredi
2020-04-02 15:50                     ` Lennart Poettering
2020-04-02 15:50                       ` Lennart Poettering
2020-04-02 17:20                       ` Miklos Szeredi
2020-04-02 17:20                         ` Miklos Szeredi
2020-04-03 11:08                         ` Lennart Poettering
2020-04-03 11:08                           ` Lennart Poettering
2020-04-03 11:48                           ` Miklos Szeredi
2020-04-03 11:48                             ` Miklos Szeredi
2020-04-03 15:01                             ` Lennart Poettering
2020-04-03 15:01                               ` Lennart Poettering
2020-04-06  9:22                               ` Miklos Szeredi
2020-04-06  9:22                                 ` Miklos Szeredi
2020-04-06 17:29                                 ` Lennart Poettering
2020-04-06 17:29                                   ` Lennart Poettering
2020-04-07  2:21                                   ` Ian Kent
2020-04-07  2:21                                     ` Ian Kent
2020-04-07 13:59                                     ` Miklos Szeredi
2020-04-07 13:59                                       ` Miklos Szeredi
2020-04-07 15:53                                       ` Lennart Poettering
2020-04-07 15:53                                         ` Lennart Poettering
2020-04-07 16:06                                         ` Miklos Szeredi
2020-04-07 16:06                                           ` Miklos Szeredi
2020-04-02 15:51                 ` David Howells
2020-04-02 15:51                   ` David Howells
2020-04-02 15:56                 ` David Howells
2020-04-02 15:56                   ` David Howells
2020-04-03  1:44             ` Ian Kent
2020-04-03  1:44               ` Ian Kent
2020-04-03 11:11               ` Lennart Poettering
2020-04-03 11:11                 ` Lennart Poettering
2020-04-03 11:38                 ` Miklos Szeredi
2020-04-03 11:38                   ` Miklos Szeredi
2020-04-03 12:05                   ` Richard Weinberger
2020-04-03 12:05                     ` Richard Weinberger
2020-04-03 15:12                   ` Lennart Poettering
2020-04-03 15:12                     ` Lennart Poettering
2020-04-03 20:30                     ` J. Bruce Fields
2020-04-03 20:30                       ` J. Bruce Fields
2020-04-06  8:35                       ` Miklos Szeredi
2020-04-06  8:35                         ` Miklos Szeredi
2020-04-06 16:07                         ` J. Bruce Fields
2020-04-06 16:07                           ` J. Bruce Fields
2020-04-06  9:17                       ` Karel Zak
2020-04-06  9:17                         ` Karel Zak
2020-04-06 16:34                         ` Linus Torvalds
2020-04-06 16:34                           ` Linus Torvalds
2020-04-06 18:46                           ` J. Bruce Fields
2020-04-06 18:46                             ` J. Bruce Fields
2020-04-06 18:48                           ` Lennart Poettering
2020-04-06 18:48                             ` Lennart Poettering
2020-04-08  3:36                             ` Linus Torvalds
2020-04-08  3:36                               ` Linus Torvalds
2020-04-03 15:36                   ` David Howells
2020-04-03 15:36                     ` David Howells
2020-04-03 15:41                     ` Lennart Poettering
2020-04-03 15:41                       ` Lennart Poettering

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