From 1bc5f09f2e1b2be8f6f737b8d5352b438fc41492 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 26 Jun 2018 14:23:23 +0200 Subject: block: Use tracked request for truncate When growing an image, block drivers (especially protocol drivers) may initialise the newly added area. I/O requests to the same area need to wait for this initialisation to be completed so that data writes don't get overwritten and reads don't read uninitialised data. To avoid overhead in the fast I/O path by adding new locking in the protocol drivers and to restrict the impact to requests that actually touch the new area, reuse the existing tracked request infrastructure in block/io.c and mark all discard requests as serialising. With this change, it is safe for protocol drivers to make .bdrv_co_truncate actually asynchronous. Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi --- include/block/block_int.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/block/block_int.h b/include/block/block_int.h index 740166a996..af71b414be 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -63,6 +63,7 @@ enum BdrvTrackedRequestType { BDRV_TRACKED_READ, BDRV_TRACKED_WRITE, BDRV_TRACKED_DISCARD, + BDRV_TRACKED_TRUNCATE, }; typedef struct BdrvTrackedRequest { -- cgit v1.2.3-55-g7522