[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen-blkback: Switch to closed state after releasing the backing device
On Wed, Sep 05, 2018 at 12:36:49PM +0200, Roger Pau Monné wrote: > On Wed, Aug 29, 2018 at 08:52:14AM +0200, Valentin Vidic wrote: > > Switching to closed state earlier can cause the block-drbd > > script to fail with 'Device is held open by someone': > > > > root: /etc/xen/scripts/block-drbd: remove XENBUS_PATH=backend/vbd/6/51712 > > kernel: [ 2222.278235] block drbd6: State change failed: Device is held > > open by someone > > kernel: [ 2222.278304] block drbd6: state = { cs:Connected > > ro:Primary/Secondary ds:UpToDate/UpToDate r----- } > > kernel: [ 2222.278340] block drbd6: wanted = { cs:Connected > > ro:Secondary/Secondary ds:UpToDate/UpToDate r----- } > > root: /etc/xen/scripts/block-drbd: Writing > > backend/vbd/6/51712/hotplug-error /etc/xen/scripts/block-drbd failed; error > > detected. backend/vbd/6/51712/hotplug-status error to xenstore. > > root: /etc/xen/scripts/block-drbd: /etc/xen/scripts/block-drbd failed; > > error detected. > > > > Signed-off-by: Valentin Vidic <Valentin.Vidic@xxxxxxxxx> > > Cc: stable@xxxxxxxxxxxxxxx > > --- > > drivers/block/xen-blkback/xenbus.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/block/xen-blkback/xenbus.c > > b/drivers/block/xen-blkback/xenbus.c > > index a4bc74e72c39..43bddc996709 100644 > > --- a/drivers/block/xen-blkback/xenbus.c > > +++ b/drivers/block/xen-blkback/xenbus.c > > @@ -323,6 +323,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) > > { > > WARN_ON(xen_blkif_disconnect(blkif)); > > xen_vbd_free(&blkif->vbd); > > + xenbus_switch_state(blkif->be->dev, XenbusStateClosed); > > kfree(blkif->be->mode); > > kfree(blkif->be); > > > > @@ -814,7 +815,6 @@ static void frontend_changed(struct xenbus_device *dev, > > > > case XenbusStateClosed: > > xen_blkif_disconnect(be->blkif); > > - xenbus_switch_state(dev, XenbusStateClosed); > > if (xenbus_dev_is_online(dev)) > > break; > > AFAICT, this will cause the backend to never switch to 'Closed' state > until the toolstack sets online to 0, which is not good IMO. > > If for example a frontend decides to close a device, the backend will > stay in state 'Closing' until the toolstack actually removes the disk > by setting online to 0. > > This will prevent resetting blk connections, as blkback will refuse to > switch to state XenbusStateInitWait unless it's at XenbusStateClosed > (see the XenbusStateInitialising case in frontend_changed), which will > never be reached with your patch. Ok, is it possible to test this somehow? > Maybe the easiest solution would be to wait in the block-drbd script > until the device is released? Maybe using fstat in a loop or one of > the drbd tools? That is an option, but I don't know if it is possible to check device release like that. Including drbd-user in CC, maybe they have some idea how to solve this. -- Valentin _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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