On 01/13/11 09:23, Milan Broz wrote:

On 01/12/2011 06:34 PM, Valdis.Kletnieks@vt.edu wrote:

quoted

Seen in a boot of yesterday's linux-next.   The 'W' flag was due to the
already-reported 'WARNING: at kernel/workqueue.c:1202 worker_enter_idle'.
Not sure if it's a block_dev or dm/LVM issue, so I'm cc:'ing both groups.  I wonder
if the fact I still have 'CONFIG_DEVTMPFS=n' is involved (it's apparently ticking off
dracut before and after the warning).

[   16.840333] dracut: Found volume group "vg_blackice" using metadata type lvm2
[   16.892282] dracut: The link /dev/vg_blackice/opt should had been created by udev but it was not found.  Falling back to direct link creation.
[   16.912627] ------------[ cut here ]------------
[   16.912635] WARNING: at fs/block_dev.c:824 bd_link_disk_holder+0x92/0x1ac()

That seems to be
WARN_ON_ONCE(!bdev->bd_holder || bdev->bd_holder_disk);
added in patch
http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=commitdiff;h=e09b457bdb7e8d23fc54dcef0930ac697d8de895
"block: simplify holder symlink handling"

dm linear just claims device in table constructor, I don't think it is bug in DM code.

The patch assumes only one holder disk for a claimed dev, which is not true.
E.g. if there are multiple LVs on a PV.

In addition to that, since claiming is done in table constructor,
there can be 2 claim instances for a slave/holder pair at a time
when you load a table while there's already an active one.
E.g. if you do lvresize.
We need consideration for this, too.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation