Just to add a little bit to this discussion, I think I'm experiencing a
similar issue. I'm using bcache to improve my laptop's I/O
performance. My configuration is, using the syntax you used,
RootFS->LVM->dm-crypt->bcache(bcache0)->(sda7)
I get pretty much the same sort of shutdown messages using the stock
Linux 3.11.5 from kernel.org on my Debian Wheezy installation.
In my case, I'm getting this message with bcache immediately over a raw
disk (with a partition on an SSD acting as the cache). I don't have the
spare hardware to test things out, but I'm guessing that this happens
whenever LVM is anywhere on the stack above bcache.
It seems probable to me that this bug is preventing my laptop from
hibernating. :( I can still put it to sleep. The hibernation process
will start correctly, but things don't come back correctly when I try to
restore: I just get fscking on my root partition, which leads me to
believe that things weren't closed up properly. (To be fair, this might
also just be a kernel regression, since my Inspiron 17R SE laptop was
running 3.10 from Debian beforehand and is running 3.11.5 from
kernel.org now.)
Just wanted to throw in the extra data. :)
Cheers,
Zach
Hi,
My system has the following block device stack:
RootFS->LVM->bcache(bcache0)->RAID5(md1)->(sda2, sdb2, sdc2)
During shutdown on Fedora I noticed the following on console:
[ 137.036846] dracut Warning: Unmounted /oldroot.
[ 137.103139] dracut: Disassembling device-mapper devices
[ 137.147160] dracut: Waiting for mdraid devices to be clean.
[ 137.158556] dracut: Disassembling mdraid devices.
mdadm: Cannot get exclusive access to /dev/md1:Perhaps a running
process, mounted filesystem or active volume group?
[ 138.247044] bcache: bcache_reboot() Stopping all devices:
[ 140.247073] bcache: bcache_reboot() Timeout waiting for devices to
be closed
[ 140.250295] Unregister pv shared memory for cpu 0
[ 140.253139] kvm: exiting hardware virtualization
So apparently bcache is (b)locking /dev/md1 during shutdown. In an
attempt to solve this, I added a "echo 1 >
/sys/block/bcache0/bcache/stop":
[ 137.036846] dracut Warning: Unmounted /oldroot.
[ 137.076580] dracut: Stopping bcache devices
STOP /sys/block/bcache0/bcache/stop
[ 137.103139] dracut: Disassembling device-mapper devices
[ 137.147160] dracut: Waiting for mdraid devices to be clean.
[ 137.158556] dracut: Disassembling mdraid devices.
mdadm: Cannot get exclusive access to /dev/md1:Perhaps a running
process, mounted filesystem or active volume group?
mdadm: Cannot get exclusive access to /dev/md1:Perhaps a running
process, mounted filesystem or active volume group?
mdadm: Cannot get exclusive access to /dev/md1:Perhaps a running
process, mounted filesystem or active volume group?
[ 137.200086] dracut: Stopping bcache cache sets
STOP /sys/fs/bcache/408c0554-9752-4126-916d-5c5fe32037d2/stop
Rebooting.
[ 138.247044] bcache: bcache_reboot() Stopping all devices:
[ 140.247073] bcache: bcache_reboot() Timeout waiting for devices to
be closed
[ 140.250295] Unregister pv shared memory for cpu 0
The 1st STOP... line is the result of a debugging "echo .." command:
for stop in /sys/block/bcache[0-9]*/bcache/stop; do
[ -f "$stop" ] || continue
echo 1 > "$stop"
echo STOP $stop
done
The second STOP does the same for the cache set, but that's not the
issue now.
From both the documentation and testing I understand that the first
STOP should mark the bcache0 device for stop as soon as it's no longer
used, in this case by LVM. So when LVM (device mapper devices) is
disassembled, bcache should actually stop the bcache0 device. But his
apparently doesn't happen. I did a test with almost the same config,
but without bcache between LVM and RAID5, in that case all works fine.
So it looks like bcache is the cause.
So I may be misunderstanding the way "echo 1 >
/sys/block/bcache0/bcache/stop" works. Are there any suggestions for
my where to look further?
Thanks,
Rolf
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