From: Tejun Heo <tj@kernel.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
"Theodore Ts'o" <tytso@mit.edu>,
Kernel development list <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@suse.de>,
Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: Revoking filesystems [was Re: Sysfs attributes racing with unregistration]
Date: Thu, 5 Jan 2012 09:11:57 -0800 [thread overview]
Message-ID: <20120105171157.GA18486@google.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1201051133490.1434-100000@iolanthe.rowland.org>
Hello,
On Thu, Jan 05, 2012 at 11:47:54AM -0500, Alan Stern wrote:
> One problem (which was reported by a user last spring) is that
> del_gendisk() calls device_del() for the disk and bdi_unregister() for
> the disk's backing_dev_info structure. Now, del_gendisk will leave the
> data structure in memory until the disk's refcount drops to 0, but
> bdi_unregister ignores refcounts and simply erases the bdi->dev
> pointer. Once this happens, any attempt to call mark_buffer_dirty()
> (for example, by ext4_commit_super) will cause an oops.
Yeah, there were multiple bugs in block device hot-removal path. I
got some of them fixed recently but didn't get to the bdi one yet.
It's a bug and needs to be fixed regardless of fs revoke support.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-01-05 17:12 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-04 16:52 Sysfs attributes racing with unregistration Alan Stern
2012-01-04 17:18 ` Tejun Heo
2012-01-04 18:13 ` Eric W. Biederman
2012-01-04 19:41 ` Alan Stern
2012-01-05 3:07 ` Eric W. Biederman
2012-01-05 15:13 ` Revoking filesystems [was Re: Sysfs attributes racing with unregistration] Alan Stern
2012-01-05 15:32 ` Tejun Heo
2012-01-05 16:03 ` Eric W. Biederman
2012-01-05 16:44 ` Tejun Heo
2012-01-05 16:47 ` Alan Stern
2012-01-05 17:11 ` Tejun Heo [this message]
2012-01-05 18:27 ` Ted Ts'o
2012-01-05 18:36 ` Tejun Heo
2012-01-05 19:28 ` Ted Ts'o
2012-01-05 20:52 ` Tejun Heo
2012-01-06 6:25 ` Alexander E. Patrakov
2012-01-07 21:01 ` Revoking filesystems [was Re: Sysfs attributes racing withunregistration] Milton Miller
2012-01-05 20:43 ` Revoking filesystems [was Re: Sysfs attributes racing with unregistration] Eric W. Biederman
2012-01-05 20:55 ` Tejun Heo
2012-01-05 18:38 ` Christoph Hellwig
2012-01-05 15:52 ` Eric W. Biederman
2013-01-14 15:11 ` watchdog code anish kumar
2012-01-05 18:18 ` Revoking filesystems [was Re: Sysfs attributes racing with unregistration] Greg KH
2012-01-04 18:13 ` Sysfs attributes racing with unregistration Alan Stern
2012-01-04 18:20 ` Tejun Heo
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