On Tue, Dec 22, 2015 at 09:59:46AM +0300, Denis V. Lunev wrote: > error: Failed to start domain rhel7 > error: internal error: process exited while connecting to monitor: > 2015-12-22T06:55:18.812637Z qemu-system-x86_64: > -drive file=/var/lib/libvirt/images/rhel7.qcow2,if=none, > id=drive-scsi0-0-0-0,format=qcow2,cache=none,aio=native: > aio=native was specified, but it requires cache.direct=on, > which was not specified. > > cache=none option was specified as seen above while the VM is unable to > start. The patch properly passed BDRV_O_NOCACHE to underlying layer. > > The problem is revealed with > commit d657c0c289e944fc22289f5c318f48da87d79dcb > Author: Kevin Wolf <kw...@redhat.com> > Date: Tue Dec 15 11:35:36 2015 +0100 > > raw-posix: Make aio=native option binding > > Signed-off-by: Denis V. Lunev <d...@openvz.org> > CC: Kevin Wolf <kw...@redhat.com> > --- > block.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/block.c b/block.c > index 411edbf..fe0fbbc 100644 > --- a/block.c > +++ b/block.c > @@ -990,6 +990,7 @@ static int bdrv_open_common(BlockDriverState *bs, > BdrvChild *file, > bs->opaque = g_malloc0(drv->instance_size); > > /* Apply cache mode options */ > + update_flags_from_options(&open_flags, opts); > update_flags_from_options(&bs->open_flags, opts); > bdrv_set_enable_write_cache(bs, bs->open_flags & BDRV_O_CACHE_WB);
I tried to review this patch and failed to understand block.c flags handling. Perhaps there is a larger problem here because I see: 1. .bdrv_open() and friends take an int flags argument in addition to the already open bs node, which has bs->open_flags. Some of the code that manipulates the flags argument in block.c updates bs->open_flags to keep them in sync. Some code does not (e.g. BDRV_O_NO_BACKING). Is this a bug? Should int flags be removed in favor of just bs->open_flags? 2. The bdrv_open_common() open_flags local variable contains different values from bs->open_flags (i.e. BDRV_O_PROTOCOL). I'm not sure whether this is intentional or a bug. Your patch syncs them but I wonder if it would be cleaner to remove the open_flags local (avoiding similar problems in the future)? 3. block/qcow2.c stashes .bdrv_open(flags) in s->flags. I'm not sure if bs->open_flags can be used instead of s->flags. That would be simpler. Maybe someone can explain how this is all supposed to work. Stefan
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