On Fri, Apr 26, 2013 at 05:04:06PM +0800, Liu Yuan wrote: > On 04/25/2013 09:06 PM, MORITA Kazutaka wrote: > > At Thu, 25 Apr 2013 20:49:39 +0800, > > Liu Yuan wrote: > >> > >> From: Liu Yuan <tailai...@taobao.com> > >> > >> Currently the 'loadvm' opertaion works as following: > >> 1. switch to the snapshot > >> 2. mark current working VDI as a snapshot > >> 3. rely on sd_create_branch to create a new working VDI based on the > >> snapshot > >> > >> This works not the same as other format as QCOW2. For e.g, > >> > >> qemu > savevm # get a live snapshot snap1 > >> qemu > savevm # snap2 > >> qemu > loadvm 1 # This will steally create snap3 of the working VDI > >> > >> Which will result in following snapshot chain: > >> > >> base <-- snap1 <-- snap2 <-- snap3 > >> ^ > >> | > >> working VDI > >> > >> snap3 was unnecessarily created and might be annoying users. > >> > >> This patch discard the unnecessary 'snap3' creation. and implement > >> rollback(loadvm) operation to the specified snapshot by > >> 1. switch to the snapshot > >> 2. delete working VDI > >> 3. rely on sd_create_branch to create a new working VDI based on the > >> snapshot > >> > >> The snapshot chain for above example will be: > >> > >> base <-- snap1 <-- snap2 > >> ^ > >> | > >> working VDI > >> > >> Cc: qemu-devel@nongnu.org > >> Cc: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp> > >> Cc: Kevin Wolf <kw...@redhat.com> > >> Cc: Stefan Hajnoczi <stefa...@redhat.com> > >> Signed-off-by: Liu Yuan <tailai...@taobao.com> > >> --- > >> v4: > >> - print an error message when NO_VDI found > >> > >> v3: > >> - let boot from snapshot behave like 'loadvm' > >> > >> v2: > >> - use do_req() because sd_delete isn't in coroutine > >> - don't break old behavior if we boot up on the snapshot by using > >> s->reverted > >> to indicate if we delete working VDI successfully > >> - fix a subtle case that sd_create_branch() isn't called yet while another > >> 'loadvm' is executed > >> > >> block/sheepdog.c | 54 > >> +++++++++++++++++++++++++++++++++++++++++++++++++++++- > >> 1 file changed, 53 insertions(+), 1 deletion(-) > > > > Reviewed-by: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp> > > Missed this one, Stefan?
Please send patches as top-level email threads instead of replies so that they get noticed. Thanks, Stefan
