Am 15.10.2012 11:13, schrieb Kevin Wolf: > Am 12.10.2012 17:52, schrieb Andreas Färber: >> Am 12.06.2012 15:44, schrieb Kevin Wolf: >>> Am 12.06.2012 15:33, schrieb Andreas Färber: >>>> Am 14.05.2012 14:20, schrieb Kevin Wolf: >>>>> Am 13.05.2012 10:03, schrieb Zhouyi Zhou: >>>>>> sometimes, qemu/kvm-0.1x will hang in endless loop in >>>>>> qcow2_alloc_cluster_offset. >>>>> >>>>> The patch looks reasonable to me. Note however that while it fixes the >>>>> hang, it still causes cluster leaks. I'm not sure if someone is >>>>> interested in picking these up for old stable releases. Andreas, I think >>>>> you were going to take 0.15? The first version that doesn't have the >>>>> problem is 1.0. >>>> >>> It's "fixed" as a side effect of the block layer conversion to >>> coroutines. Not exactly the kind of patches you'd want to cherry-pick >>> for stable-0.15. >>> >>> The better fix for 0.15 could be to backport the new behaviour of >>> coroutine based requests with bdrv_aio_cancel: >>> >>> static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb) >>> { >>> qemu_aio_flush(); >>> } >>> >>> Using that as the implementation for qcow2_aio_cancel should be safe and >>> fix this problem. >> >> [...] stable-0.15 does not have coroutines, so I don't >> understand what exactly you're suggesting as alternative here: Backport >> the whole coroutine feature including coroutine function above? Or just >> call qemu_aio_flush() in place of what? This is old qcow2_aio_cancel(): > > No, that was qcow2_aio_flush. ;-)
Ugh, what a copy-and-paste error... ;-) > What I'm suggesting (not even compile tested!) is: > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > > diff --git a/block/qcow2.c b/block/qcow2.c > index 48e1b95..d665675 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -388,10 +388,7 @@ typedef struct QCowAIOCB { > > static void qcow2_aio_cancel(BlockDriverAIOCB *blockacb) > { > - QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common); > - if (acb->hd_aiocb) > - bdrv_aio_cancel(acb->hd_aiocb); > - qemu_aio_release(acb); > + qemu_aio_flush(); > } > > static AIOPool qcow2_aio_pool = { Compiles fine. Is there a particular test case to invoke this code path? Does this attempt to fix the cluster leaks you mentioned as well, or just the cluster allocation endless loop? Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg