From e900a7b748316b5b5a98e41dde36a0cb8e15be5f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 4 Sep 2009 19:01:15 +0200 Subject: block: add enable_write_cache flag Add a enable_write_cache flag in the block driver state, and use it to decide if we claim to have a volatile write cache that needs controlled flushing from the guest. The flag is off if cache=writethrough is defined because O_DSYNC guarantees that every write goes to stable storage, and it is on for cache=none and cache=writeback. Both scsi-disk and ide now use the new flage, changing from their defaults of always off (ide) or always on (scsi-disk). Signed-off-by: Christoph Hellwig Signed-off-by: Anthony Liguori --- block_int.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block_int.h') diff --git a/block_int.h b/block_int.h index 3e4b4a387b..f95c80b906 100644 --- a/block_int.h +++ b/block_int.h @@ -158,6 +158,9 @@ struct BlockDriverState { /* the memory alignment required for the buffers handled by this driver */ int buffer_alignment; + /* do we need to tell the quest if we have a volatile write cache? */ + int enable_write_cache; + /* NOTE: the following infos are only hints for real hardware drivers. They are not used by the block driver */ int cyls, heads, secs, translation; -- cgit v1.2.3