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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Karel Zak <kzak@redhat.com>, David Howells <dhowells@redhat.com>,
	Ian Kent <raven@themaw.net>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Steven Whitehouse <swhiteho@redhat.com>,
	Miklos Szeredi <mszeredi@redhat.com>,
	viro <viro@zeniv.linux.org.uk>,
	Christian Brauner <christian@brauner.io>,
	Jann Horn <jannh@google.com>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Linux API <linux-api@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 00/17] VFS: Filesystem information and notifications [ver #17]
Date: Tue, 3 Mar 2020 14:43:16 +0100	[thread overview]
Message-ID: <20200303134316.GA2509660@kroah.com> (raw)
In-Reply-To: <CAJfpegt0aQVvoDeBXOu2xZh+atZQ+q5uQ_JRxe46E8cZ7sHRwg@mail.gmail.com>

On Tue, Mar 03, 2020 at 02:34:42PM +0100, Miklos Szeredi wrote:
> On Tue, Mar 3, 2020 at 2:14 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> 
> > > Unlimited beers for a 21-line kernel patch?  Sign me up!
> > >
> > > Totally untested, barely compiled patch below.
> >
> > Ok, that didn't even build, let me try this for real now...
> 
> Some comments on the interface:

Ok, hey, let's do this proper :)

> O_LARGEFILE can be unconditional, since offsets are not exposed to the caller.

Good point.

> Use the openat2 style arguments; limit the accepted flags to sane ones
> (e.g. don't let this syscall create a file).

Yeah, I just added that check to my local version:
	/* Mask off all O_ flags as we only want to read from the file */
	flags &= ~(VALID_OPEN_FLAGS);
	flags |= O_RDONLY | O_LARGEFILE;

> If buffer is too small to fit the whole file, return error.

Why?  What's wrong with just returning the bytes asked for?  If someone
only wants 5 bytes from the front of a file, it should be fine to give
that to them, right?

> Verify that the number of bytes read matches the file size, otherwise
> return error (may need to loop?).

No, we can't "match file size" as sysfs files do not really have a sane
"size".  So I don't want to loop at all here, one-shot, that's all you
get :)

Let me actually do this and try it out for real.

/me has no idea what he is getting himself into...

thanks,

greg k-h

  reply	other threads:[~2020-03-03 13:43 UTC|newest]

Thread overview: 117+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-21 18:01 [PATCH 00/17] VFS: Filesystem information and notifications [ver #17] David Howells
2020-02-21 18:01 ` [PATCH 01/17] watch_queue: Add security hooks to rule on setting mount and sb watches " David Howells
2020-02-21 18:02 ` [PATCH 02/17] watch_queue: Implement mount topology and attribute change notifications " David Howells
2020-02-21 18:02 ` [PATCH 03/17] watch_queue: sample: Display mount tree " David Howells
2020-02-21 18:02 ` [PATCH 04/17] watch_queue: Introduce a non-repeating system-unique superblock ID " David Howells
2020-02-21 18:02 ` [PATCH 05/17] watch_queue: Add superblock notifications " David Howells
2020-02-21 18:02 ` [PATCH 06/17] watch_queue: sample: Display " David Howells
2020-02-21 18:02 ` [PATCH 07/17] fsinfo: Add fsinfo() syscall to query filesystem information " David Howells
2020-02-26  2:29   ` Aleksa Sarai
2020-02-28 14:44   ` David Howells
2020-02-21 18:02 ` [PATCH 08/17] fsinfo: Provide a bitmap of supported features " David Howells
2020-02-21 18:03 ` [PATCH 09/17] fsinfo: Allow fsinfo() to look up a mount object by ID " David Howells
2020-02-21 18:03 ` [PATCH 10/17] fsinfo: Allow mount information to be queried " David Howells
2020-03-04 14:58   ` Miklos Szeredi
2020-03-04 16:10   ` Miklos Szeredi
2020-02-21 18:03 ` [PATCH 11/17] fsinfo: sample: Mount listing program " David Howells
2020-02-21 18:03 ` [PATCH 12/17] fsinfo: Allow the mount topology propogation flags to be retrieved " David Howells
2020-02-21 18:03 ` [PATCH 13/17] fsinfo: Query superblock unique ID and notification counter " David Howells
2020-02-21 18:03 ` [PATCH 14/17] fsinfo: Add API documentation " David Howells
2020-02-21 18:03 ` [PATCH 15/17] fsinfo: Add support for AFS " David Howells
2020-02-21 18:03 ` [PATCH 16/17] fsinfo: Add example support for Ext4 " David Howells
2020-02-21 18:04 ` [PATCH 17/17] fsinfo: Add example support for NFS " David Howells
2020-02-21 20:21 ` [PATCH 00/17] VFS: Filesystem information and notifications " James Bottomley
2020-02-24 10:24   ` Miklos Szeredi
2020-02-24 14:55     ` James Bottomley
2020-02-24 15:28       ` Miklos Szeredi
2020-02-25 12:13         ` Steven Whitehouse
2020-02-25 15:28           ` James Bottomley
2020-02-25 15:47             ` Steven Whitehouse
2020-02-26  9:11             ` Miklos Szeredi
2020-02-26 10:51               ` Steven Whitehouse
2020-02-27  5:06               ` Ian Kent
2020-02-27  9:36                 ` Miklos Szeredi
2020-02-27 11:34                   ` Ian Kent
2020-02-27 13:45                     ` Miklos Szeredi
2020-02-27 15:14                       ` Karel Zak
2020-02-28  0:43                         ` Ian Kent
2020-02-28  8:35                           ` Miklos Szeredi
2020-02-28 12:27                             ` Greg Kroah-Hartman
2020-02-28 16:24                               ` Miklos Szeredi
2020-02-28 17:15                                 ` Al Viro
2020-03-02  8:43                                   ` Miklos Szeredi
2020-03-02 10:34                                 ` Karel Zak
2020-02-28 16:42                               ` David Howells
2020-02-28 15:08                             ` James Bottomley
2020-02-28 15:40                               ` Miklos Szeredi
2020-02-28  0:12                       ` Ian Kent
2020-02-28 15:52             ` Christian Brauner
2020-02-28 16:36             ` David Howells
2020-03-02  9:09               ` Miklos Szeredi
2020-03-02  9:38                 ` Greg Kroah-Hartman
2020-03-03  5:27                 ` Ian Kent
2020-03-03  7:46                   ` Miklos Szeredi
2020-03-06 16:25                     ` Miklos Szeredi
2020-03-06 19:43                       ` Al Viro
2020-03-06 19:54                         ` Miklos Szeredi
2020-03-06 19:58                         ` Al Viro
2020-03-06 20:05                           ` Al Viro
2020-03-06 20:11                             ` Miklos Szeredi
2020-03-06 20:37                             ` Al Viro
2020-03-06 20:38                               ` Al Viro
2020-03-06 20:45                                 ` Al Viro
2020-03-06 20:49                                   ` Al Viro
2020-03-06 20:51                                     ` Miklos Szeredi
2020-03-06 21:28                                       ` Al Viro
2020-03-06 20:56                                     ` Al Viro
2020-03-06 20:51                                   ` Miklos Szeredi
2020-03-07  9:48                       ` Greg Kroah-Hartman
2020-03-07 20:48                         ` Miklos Szeredi
2020-03-03  9:12                   ` David Howells
2020-03-03  9:26                     ` Miklos Szeredi
2020-03-03  9:48                       ` Miklos Szeredi
2020-03-03 10:21                         ` Steven Whitehouse
2020-03-03 10:32                           ` Miklos Szeredi
2020-03-03 11:09                             ` Ian Kent
2020-03-03 10:00                       ` Christian Brauner
2020-03-03 10:13                         ` Miklos Szeredi
2020-03-03 10:25                           ` Christian Brauner
2020-03-03 11:33                             ` Miklos Szeredi
2020-03-03 11:56                               ` Christian Brauner
2020-03-03 11:38                       ` Karel Zak
2020-03-03 13:03                         ` Greg Kroah-Hartman
2020-03-03 13:14                           ` Greg Kroah-Hartman
2020-03-03 13:34                             ` Miklos Szeredi
2020-03-03 13:43                               ` Greg Kroah-Hartman [this message]
2020-03-03 14:10                                 ` Greg Kroah-Hartman
2020-03-03 14:13                                   ` Jann Horn
2020-03-03 14:24                                     ` Greg Kroah-Hartman
2020-03-03 15:44                                       ` Jens Axboe
2020-03-03 16:37                                         ` Greg Kroah-Hartman
2020-03-03 16:51                                         ` Jeff Layton
2020-03-03 16:55                                           ` Jens Axboe
2020-03-03 19:02                                             ` Jeff Layton
2020-03-03 19:07                                               ` Jens Axboe
2020-03-03 19:23                                               ` Jens Axboe
2020-03-03 19:43                                                 ` Jeff Layton
2020-03-03 20:33                                                   ` Jens Axboe
2020-03-03 21:03                                                     ` Jeff Layton
2020-03-03 21:20                                                       ` Jens Axboe
2020-03-03 14:10                                 ` Miklos Szeredi
2020-03-03 14:29                                   ` Greg Kroah-Hartman
2020-03-03 14:40                                     ` Jann Horn
2020-03-03 16:51                                       ` Greg Kroah-Hartman
2020-03-03 16:57                                         ` Jann Horn
2020-03-03 20:15                                         ` Greg Kroah-Hartman
2020-03-03 14:40                                   ` David Howells
2020-03-04  4:20                                   ` Ian Kent
2020-03-03 14:19                                 ` David Howells
2020-03-03 16:59                                   ` Greg Kroah-Hartman
2020-03-03 14:23                               ` Christian Brauner
2020-03-03 15:23                                 ` Greg Kroah-Hartman
2020-03-03 15:53                                 ` David Howells
2020-03-04  2:01                           ` Ian Kent
2020-03-04 15:22                             ` Karel Zak
2020-03-04 16:49                               ` Greg Kroah-Hartman
2020-03-04 17:55                                 ` Karel Zak
2020-03-03 14:09                         ` David Howells

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