[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [xen-unstable test] 19308: regressions - FAIL
On Mon, Sep 16, 2013 at 01:43:57PM +0100, Ian Campbell wrote: [...] > > > I've tracked this down to libxl writing a wrong physical-device > > > xenstore node when using regular files. When using block devices libxl > > > can write the physical-device because it can be fetched without > > > requiring the execution of the block script, but with regular files it > > > is not true, we must first execute the block script in order to mount > > > the regular file into a loop device and then fetch the physical-device > > > from the loop device to which the image has been mounted. Following > > > patch solves the issue for me. > > > > > > > Yes, that's the in question I think. That code snippet was introduced in: > > > > commit 15116f1c254a8aa7774e2f73a3e1340a6decd867 > > Author: Ian Campbell <Ian.Campbell@xxxxxxxxxx> > > Date: Tue Aug 7 14:26:29 2012 +0100 > > > > libxl: write physical-device node if user did not supply a block script > > > > This reverts one of the intentional changes from 25733:353bc0801b11. > > That change exposed an issue with the xl migration protocol, which > > although safe triggers the hotplug scripts device sharing logic. > > > > For 4.2 we disable this logic by writing the physical-device xenstore > > node ourselves if a user did not supply a script. If the user did > > supply a script then we continue to rely on it to write the > > physical-device node (not least because the script may create the > > device and therefore it is not available before we run the script). > > > > This means that to support localhost migration a block hotplug script > > needs to be robust against adding a device twice and should not > > deactivate the device until it has been removed twice. > > > > This should be revisited for 4.3. > > > > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> > > Acked-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx> > > Committed-by: Ian Campbell <ian.campbell@xxxxxxxxxx> > > > > And in the commit message it says this behavior should be revisited. > > Which never happened :-( > > I don't remember exactly but I think the real fix is a reworking of the > sequencing of block device attach/detach vs the migration stop and copy > phase, not a simple tweak IIRC. > > > Tracing back to 25733 > > (http://xenbits.xen.org/hg/xen-unstable.hg/rev/353bc0801b11) > > things look more complicated. One interesting snippet in the commit > > message is: > > > > - libxl should not write the "physical-device" node. This is the > > responsibility of the block script. Writing the "physical-device" > > node in libxl basically completely short-cuts the standard block > > hotplug script which uses "physical-device" to know if it has run > > already or not. > > > > That makes me believe the following fix is the correct thing to do in > > long term. > > > > I have to admit that I cannot fully consume the commit message of 25733 > > in one day so unless you (Ian) can confirm Roger's fix will not cause > > further > > regression otherwise I would suggest reverting my change at the moment. > > Can you test some lifecycle operations, in particular localhost > migrations with both phy:// and file:// devices to see if it fixes it? > If not then we can revert. > Unfortunately with Roger's patch applied local migration for raw format file disk doesn't work. xc: detail: Save exit of domid 69 with rc=0 libxl: error: libxl_exec.c:118:libxl_report_child_exitstatus: /etc/xen/scripts/block add [8102] exited with error status 1 libxl: error: libxl_device.c:1021:device_hotplug_child_death_cb: script: File /data/s0.raw is loopback-mounted through /dev/loop0, which is mounted in a guest domain, and so cannot be mounted now. libxl: error: libxl_create.c:932:domcreate_launch_dm: unable to add disk devices libxl: error: libxl_exec.c:118:libxl_report_child_exitstatus: /etc/xen/scripts/block remove [8181] exited with error status 1 libxl: error: libxl_device.c:1021:device_hotplug_child_death_cb: script: /etc/xen/scripts/block failed; error detected. migration target: Domain creation failed (code -3). libxl: error: libxl_utils.c:393:libxl_read_exactly: file/stream truncated reading ready message from migration receiver stream libxl: info: libxl_exec.c:118:libxl_report_child_exitstatus: migration target process [8091] exited with error status 3 Migration failed, resuming at sender. > Perhaps rather than removing that block entirely it should be > conditional on S_ISBLK? > With the conditional on S_ISBLK, raw format file mounted to loopdev, local migration still breaks with above error. So for now please revert that change. Wei. > Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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