Reviewed the code, except Paolo's comments, function seems fine.
Il 15/05/2013 16:34, Stefan Hajnoczi ha scritto:
The bdrv_add_before_write_cb() function installs a callback that is
invoked before a write request is processed. This will be used to
implement copy-on-write point-in-time snapshots where we need to copy
out old data before overwriting it.
Perhaps a notifier list that receives the BdrvTrackedRequest? (BTW we
should probably remove all the notifier_remove wrappers, they're useless).
The BdrvTrackedRequest pointer would also act as a unique id of the request.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block.c | 37 +++++++++++++++++++++++++++++++++++++
include/block/block_int.h | 32 ++++++++++++++++++++++++++++++++
2 files changed, 69 insertions(+)
diff --git a/block.c b/block.c
index 3f87489..0fd7167 100644
--- a/block.c
+++ b/block.c
@@ -308,6 +308,7 @@ BlockDriverState *bdrv_new(const char *device_name)
}
bdrv_iostatus_disable(bs);
notifier_list_init(&bs->close_notifiers);
+ QTAILQ_INIT(&bs->before_write_cbs);
return bs;
}
@@ -1383,6 +1384,8 @@ void bdrv_close(BlockDriverState *bs)
bs->growable = 0;
QDECREF(bs->options);
bs->options = NULL;
+ assert(QTAILQ_EMPTY(&bs->before_write_cbs));
+ QTAILQ_INIT(&bs->before_write_cbs);
INIT not needed if you assert before.
Paolo
--
Best Regards
Wenchao Xia
