linux-block.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jens Axboe <axboe@kernel.dk>
To: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>,
	linux-kernel@vger.kernel.org
Cc: linux-block@vger.kernel.org, nbd@other.debian.org,
	josef@toxicpanda.com, idryomov@redhat.com, xiubli@redhat.com
Subject: Re: [PATCH] nbd: provide a way for userspace processes to identify device backends
Date: Wed, 16 Jun 2021 06:59:33 -0600	[thread overview]
Message-ID: <f3035a3f-4494-929f-5c21-ba921a77ea6c@kernel.dk> (raw)
In-Reply-To: <20210429102828.31248-1-prasanna.kalever@redhat.com>

On 4/29/21 4:28 AM, Prasanna Kumar Kalever wrote:
> Problem:
> On reconfigure of device, there is no way to defend if the backend
> storage is matching with the initial backend storage.
> 
> Say, if an initial connect request for backend "pool1/image1" got
> mapped to /dev/nbd0 and the userspace process is terminated. A next
> reconfigure request within NBD_ATTR_DEAD_CONN_TIMEOUT is allowed to
> use /dev/nbd0 for a different backend "pool1/image2"
> 
> For example, an operation like below could be dangerous:
> 
> $ sudo rbd-nbd map --try-netlink rbd-pool/ext4-image
> /dev/nbd0
> $ sudo blkid /dev/nbd0
> /dev/nbd0: UUID="bfc444b4-64b1-418f-8b36-6e0d170cfc04" TYPE="ext4"
> $ sudo pkill -9 rbd-nbd
> $ sudo rbd-nbd attach --try-netlink --device /dev/nbd0 rbd-pool/xfs-image
> /dev/nbd0
> $ sudo blkid /dev/nbd0
> /dev/nbd0: UUID="d29bf343-6570-4069-a9ea-2fa156ced908" TYPE="xfs"
> 
> Solution:
> Provide a way for userspace processes to keep some metadata to identify
> between the device and the backend, so that when a reconfigure request is
> made, we can compare and avoid such dangerous operations.
> 
> With this solution, as part of the initial connect request, backend
> path can be stored in the sysfs per device config, so that on a reconfigure
> request it's easy to check if the backend path matches with the initial
> connect backend path.
> 
> Please note, ioctl interface to nbd will not have these changes, as there
> won't be any reconfigure.

Applied, thanks.

-- 
Jens Axboe


      parent reply	other threads:[~2021-06-16 12:59 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-29 10:28 Prasanna Kumar Kalever
2021-04-30  2:14 ` Xiubo Li
2021-05-17 14:42   ` Prasanna Kalever
2021-05-18  0:29 ` Ming Lei
2021-05-18  7:52   ` Prasanna Kalever
2021-05-18  9:24     ` Ming Lei
2021-05-18  9:49       ` Prasanna Kalever
2021-05-19  7:54         ` Ming Lei
2021-05-19 14:17           ` Prasanna Kalever
2021-05-19 14:33     ` Matteo Croce
2021-05-26 14:13       ` Matteo Croce
2021-05-27  5:22         ` Prasanna Kalever
2021-06-16  8:42 ` Prasanna Kalever
2021-06-16 12:59 ` Jens Axboe [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=f3035a3f-4494-929f-5c21-ba921a77ea6c@kernel.dk \
    --to=axboe@kernel.dk \
    --cc=idryomov@redhat.com \
    --cc=josef@toxicpanda.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=nbd@other.debian.org \
    --cc=prasanna.kalever@redhat.com \
    --cc=xiubli@redhat.com \
    --subject='Re: [PATCH] nbd: provide a way for userspace processes to identify device backends' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).