Re: [libvirt] [PATCH] blockcopy: check dst = identical device

On 07/29/2014 03:59 AM, Chunyan Liu wrote: > Check whether dst is the same device as source, if yes, report > error and exit. > > Currently if dst is the same device as source, blockcopy is still > going and qemu 'drive-mirror' is executed. Considering that: > a). blockcopy to the same device is meaningless. b.) result is > unexpected. (tested with block device whose source path is /dev/sdaX, > after blockcopy, shutdown VM and then create VM from xml again, the > VM cannot be started.) This case should not be allowed. > > Signed-off-by: Chunyan Liu <cyliu(a)suse.com&gt; > --- > src/qemu/qemu_driver.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > index 704ba39..87a3790 100644 > --- a/src/qemu/qemu_driver.c > +++ b/src/qemu/qemu_driver.c > @@ -15309,6 +15309,13 @@ qemuDomainBlockCopy(virDomainObjPtr vm, > } > > /* Prepare the destination file. */ > + if (STREQ(disk->src->path, dest)) { STREQ is too weak (consider symlinks, or even "a/b" vs. "a//b"). It will catch some cases, but not all. I don't know that we can reliably detect all possible ways the user can shoot themselves in the foot, so I'm not sure this patch is a good idea.