[PATCH] dm missing bdput/thaw_bdev at removal

[PATCH] dm missing bdput/thaw_bdev at removal

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 586 bytes --]

Hello,

The following script stalls at the 2nd suspend.
It's because bdput() isn't called for the suspended_bdev.

So the inode with bd_mount_sem held is just reused
in the next mapped_device device.
Then dm_suspend will try to freeze_bdev and wait forever.

Attached patch fixes this problem.

------------------------------------------------------------
#!/bin/sh -x

map=a
while true; do
  dmsetup create $map --notable
  dmsetup suspend $map
  dmsetup remove $map
done
------------------------------------------------------------

-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: dm-missing-bdput.patch --]
[-- Type: text/x-patch, Size: 638 bytes --]

Need to unfreeze and release bdev
otherwise the bdev inode with inconsistent state is reused later
and cause problem.

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

--- linux-2.6.15.orig/drivers/md/dm.c	2006-02-23 18:28:23.000000000 -0500
+++ linux-2.6.15/drivers/md/dm.c	2006-02-23 18:29:04.000000000 -0500
@@ -812,6 +812,10 @@ static struct mapped_device *alloc_dev(u
 
 static void free_dev(struct mapped_device *md)
 {
+	if (md->suspended_bdev) {
+		thaw_bdev(md->suspended_bdev, NULL);
+		bdput(md->suspended_bdev);
+	}
 	free_minor(md->disk->first_minor);
 	mempool_destroy(md->tio_pool);
 	mempool_destroy(md->io_pool);

Re: [dm-devel] [PATCH] dm missing bdput/thaw_bdev at removal

[Alasdair G Kergon]

On Thu, Feb 23, 2006 at 07:05:09PM -0500, Jun'ichi Nomura wrote:
> Then dm_suspend will try to freeze_bdev and wait forever.
 
> Attached patch fixes this problem.

Indeed - well spotted!

Alasdair
-- 
agk@redhat.com