From: Bart Van Assche <bart.vanassche@sandisk.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: James Bottomley <jbottomley@parallels.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Jens Axboe <axboe@fb.com>, Tejun Heo <tj@kernel.org>,
Jan Kara <jack@suse.cz>, Hannes Reinecke <hare@suse.de>,
Aaro Koskinen <aaro.koskinen@iki.fi>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH] Fix a bdi reregistration race, v2
Date: Tue, 24 Nov 2015 15:23:21 -0800 [thread overview]
Message-ID: <5654F169.6070000@sandisk.com> (raw)
In-Reply-To: <20151124231331.GA25591@infradead.org>
On 11/24/2015 03:13 PM, Christoph Hellwig wrote:
> What sort of re-registration is this? Seems like we should only
> release the minor number once the bdi is released.
Hello Christoph,
As you most likely know the BDI device name for disks is based on the
device major and minor number:
$ ls -l /dev/sda
brw-rw---- 1 root disk 8, 0 Nov 24 14:53 /dev/sda
$ ls -l /sys/block/sda/bdi
lrwxrwxrwx 1 root root 0 Nov 24 15:17 /sys/block/sda/bdi ->
../../../../../../../../virtual/bdi/8:0
So if a driver stops using a (major, minor) number pair and the same
device number is reused before the bdi device has been released the
warning mentioned in the patch description at the start of this thread
is triggered. This patch fixes that race by removing the bdi device from
sysfs during the __scsi_remove_device() call instead of when the bdi
device is released.
Bart.
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next prev parent reply other threads:[~2015-11-24 23:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 22:13 [PATCH] Fix a bdi reregistration race, v2 Bart Van Assche
2015-11-20 22:43 ` Aaro Koskinen
2015-11-20 22:55 ` Bart Van Assche
2015-11-24 23:13 ` Christoph Hellwig
2015-11-24 23:23 ` Bart Van Assche [this message]
2015-11-25 8:47 ` Christoph Hellwig
2015-11-25 14:59 ` Bart Van Assche
2015-12-01 0:57 ` Martin K. Petersen
2015-12-01 1:18 ` Bart Van Assche
2015-12-01 7:23 ` Christoph Hellwig
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