From: David Lehman <dlehman@redhat.com>
To: Ray Strode <rstrode@redhat.com>, Steven Whitehouse <swhiteho@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
David Howells <dhowells@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
raven@themaw.net, keyrings@vger.kernel.org,
linux-usb@vger.kernel.org,
linux-block <linux-block@vger.kernel.org>,
Christian Brauner <christian@brauner.io>,
LSM List <linux-security-module@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Ian Kent <ikent@redhat.com>
Subject: Re: Why add the general notification queue and its sources
Date: Thu, 05 Sep 2019 16:09:58 -0400
Message-ID: <d19e8783e7fe47e51fbc12bf33c95fea16c93070.camel@redhat.com> (raw)
In-Reply-To: <CAKCoTu7ms4ckwDA_-onuJg+famnMzGZE9gGUcqqMz0kCAAECRg@mail.gmail.com>
On Thu, 2019-09-05 at 14:51 -0400, Ray Strode wrote:
> Hi,
>
> On Thu, Sep 5, 2019 at 2:37 PM Steven Whitehouse <swhiteho@redhat.com
> > wrote:
> > The original reason for the mount notification mechanism was so
> > that we
> > are able to provide information to GUIs and similar filesystem and
> > storage management tools, matching the state of the filesystem with
> > the
> > state of the underlying devices. This is part of a larger project
> > entitled "Project Springfield" to try and provide better management
> > tools for storage and filesystems. I've copied David Lehman in,
> > since he
> > can provide a wider view on this topic.
> So one problem that I've heard discussed before is what happens in a
> thinp
> setup when the disk space is overallocated and gets used up. IIRC,
> the
> volumes just sort of eat themselves?
>
> Getting proper notification of looming catastrophic failure to the
> workstation user
> before it's too late would be useful, indeed.
>
> I don't know if this new mechanism dhowells has development can help
> with that,
My understanding is that there is already a dm devent that gets sent
when the low water mark is crossed for a thin pool, but there is
nothing in userspace that knows how to effectively get the user's
attention at that time.
> and/or if solving that problem is part of the Project Springfield
> initiative or not. Do you
> know off hand?
We have been looking into building a userspace event notification
service (for storage, initially) to aggregate and add context to low-
level events such as these, providing a single source for all kinds of
storage events with an excellent signal:noise ratio. Thin pool
exhaustion is high on the list of problems we would want to address.
David
next prev parent reply index
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 22:15 [PATCH 00/11] Keyrings, Block and USB notifications [ver #8] David Howells
2019-09-04 22:15 ` [PATCH 01/11] uapi: General notification ring definitions " David Howells
2019-09-04 22:16 ` [PATCH 02/11] security: Add hooks to rule on setting a watch " David Howells
2019-09-04 22:16 ` [PATCH 03/11] security: Add a hook for the point of notification insertion " David Howells
2019-09-04 22:16 ` [PATCH 04/11] General notification queue with user mmap()'able ring buffer " David Howells
2019-09-04 22:16 ` [PATCH 05/11] keys: Add a notification facility " David Howells
2019-09-04 22:16 ` [PATCH 06/11] Add a general, global device notification watch list " David Howells
2019-09-04 22:16 ` [PATCH 07/11] block: Add block layer notifications " David Howells
2019-09-04 22:16 ` [PATCH 08/11] usb: Add USB subsystem " David Howells
2019-09-04 22:17 ` [PATCH 09/11] Add sample notification program " David Howells
2019-09-04 22:17 ` [PATCH 10/11] selinux: Implement the watch_key security hook " David Howells
2019-09-04 22:17 ` [PATCH 11/11] smack: Implement the watch_key and post_notification hooks " David Howells
2019-09-04 22:28 ` [PATCH 00/11] Keyrings, Block and USB notifications " Linus Torvalds
2019-09-05 17:01 ` Why add the general notification queue and its sources David Howells
2019-09-05 17:19 ` Linus Torvalds
2019-09-05 18:32 ` Ray Strode
2019-09-05 20:39 ` Linus Torvalds
2019-09-06 19:32 ` Ray Strode
2019-09-06 19:41 ` Ray Strode
2019-09-06 19:53 ` Robbie Harwood
2019-09-05 21:32 ` David Howells
2019-09-05 22:08 ` Linus Torvalds
2019-09-05 23:18 ` David Howells
2019-09-06 0:07 ` Linus Torvalds
2019-09-06 10:09 ` David Howells
2019-09-06 15:35 ` Linus Torvalds
2019-09-06 15:53 ` Linus Torvalds
2019-09-06 16:12 ` Steven Whitehouse
2019-09-06 17:07 ` Linus Torvalds
2019-09-06 17:14 ` Linus Torvalds
2019-09-06 21:19 ` David Howells
2019-09-06 17:14 ` Andy Lutomirski
2019-09-05 18:37 ` Steven Whitehouse
2019-09-05 18:51 ` Ray Strode
2019-09-05 20:09 ` David Lehman [this message]
2019-09-05 18:33 ` Greg Kroah-Hartman
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