Linux block layer
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
	Lekshmi Pillai <lekshmicpillai@in.ibm.com>,
	NeilBrown <neilb@suse.de>, Omar Sandoval <osandov@osandov.com>
Subject: Re: [PATCH 02/11] block: Fix race of bdev open with gendisk shutdown
Date: Mon, 6 Mar 2017 17:04:59 -0500	[thread overview]
Message-ID: <20170306220459.GJ26127@htj.duckdns.org> (raw)
In-Reply-To: <20170306163404.1238-3-jack@suse.cz>

Hello,

On Mon, Mar 06, 2017 at 05:33:55PM +0100, Jan Kara wrote:
> +	disk->flags &= ~GENHD_FL_UP;
> +	/*
> +	 * Make sure __blkdev_open() sees the disk is going away before
> +	 * starting to unhash bdev inodes.
> +	 */
> +	smp_wmb();

But which rmb is this paired with?  Without paring memory barriers
don't do anything.  Given that this isn't a super hot path, I think
it'd be far better to stick to a simpler synchronization mechanism.

Thanks.

-- 
tejun

  reply	other threads:[~2017-03-06 22:04 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-06 16:33 [PATCH 0/11 v3] block: Fix block device shutdown related races Jan Kara
2017-03-06 16:33 ` [PATCH 01/11] block: Fix bdi assignment to bdev inode when racing with disk delete Jan Kara
2017-03-06 22:01   ` Tejun Heo
2017-03-07  6:47   ` Hannes Reinecke
2017-03-06 16:33 ` [PATCH 02/11] block: Fix race of bdev open with gendisk shutdown Jan Kara
2017-03-06 22:04   ` Tejun Heo [this message]
2017-03-07 11:14     ` Jan Kara
2017-03-07 19:43       ` Tejun Heo
2017-03-08 14:25         ` Jan Kara
2017-03-06 16:33 ` [PATCH 03/11] bdi: Mark congested->bdi as internal Jan Kara
2017-03-06 16:33 ` [PATCH 04/11] bdi: Make wb->bdi a proper reference Jan Kara
2017-03-06 16:33 ` [PATCH 05/11] bdi: Move removal from bdi->wb_list into wb_shutdown() Jan Kara
2017-03-06 16:33 ` [PATCH 06/11] bdi: Shutdown writeback on all cgwbs in cgwb_bdi_destroy() Jan Kara
2017-03-06 22:08   ` Tejun Heo
2017-03-06 16:34 ` [PATCH 07/11] bdi: Do not wait for cgwbs release in bdi_unregister() Jan Kara
2017-03-06 22:08   ` Tejun Heo
2017-03-06 16:34 ` [PATCH 08/11] bdi: Rename cgwb_bdi_destroy() to cgwb_bdi_unregister() Jan Kara
2017-03-06 16:34 ` [PATCH 09/11] block: Fix oops in locked_inode_to_wb_and_lock_list() Jan Kara
2017-03-06 16:34 ` [PATCH 10/11] kobject: Export kobject_get_unless_zero() Jan Kara
2017-03-06 16:34 ` [PATCH 11/11] block: Fix oops scsi_disk_get() Jan Kara
  -- strict thread matches above, loose matches on Subject: below --
2017-03-13 15:13 [PATCH 0/11 v4] block: Fix block device shutdown related races Jan Kara
2017-03-13 15:14 ` [PATCH 02/11] block: Fix race of bdev open with gendisk shutdown Jan Kara
2017-03-21 16:19   ` Tejun Heo
2017-03-23  0:21     ` Jan Kara
2017-03-23 15:38       ` Tejun Heo
2017-11-17  6:51   ` Hou Tao
2017-11-20 16:43     ` Jan Kara
2017-11-24  3:12       ` Hou Tao

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=20170306220459.GJ26127@htj.duckdns.org \
    --to=tj@kernel.org \
    --cc=axboe@kernel.dk \
    --cc=bauerman@linux.vnet.ibm.com \
    --cc=dan.j.williams@intel.com \
    --cc=hch@infradead.org \
    --cc=jack@suse.cz \
    --cc=lekshmicpillai@in.ibm.com \
    --cc=linux-block@vger.kernel.org \
    --cc=neilb@suse.de \
    --cc=osandov@osandov.com \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox