Re: [Qemu-devel] [PATCH V5 03/13] block: add bdrv_can_read_snapshot() function

[Wenchao Xia]

于 2013-1-29 20:37, Kevin Wolf 写道:

Am 25.01.2013 19:11, schrieb Eric Blake:

On 01/23/2013 07:57 PM, Wenchao Xia wrote:

   Compared to bdrv_can_snapshot(), this function return whether
bs* is ready to read snapshot info from instead of write. If yes,
caller can then query snapshot information, but taking snapshot
is not always possible for that *bs may be read only.

Signed-off-by: Wenchao Xia <xiaw...@linux.vnet.ibm.com>
---
  block.c               |   19 +++++++++++++++++++
  include/block/block.h |    1 +
  2 files changed, 20 insertions(+), 0 deletions(-)

+/* return whether internal snapshot can be read on @bs */
+int bdrv_can_read_snapshot(BlockDriverState *bs)
+{

+/* return whether internal snapshot can be write on @bs */
  int bdrv_can_snapshot(BlockDriverState *bs)

I see you just copied existing code; but any reason why these functions
return int instead of bool?  Would that be worth a separate cleanup patch?

More importantly, you shouldn't copy code. Make both of them small
wrappers around a static helper functions that contains the existing code.

Kevin

  I tried that before, but found that hard to wrapper around a common
function, because both need to recusively check some condition.



--
Best Regards

Wenchao Xia