block: always open drivers in writeback mode

Formats are entirely in charge of flushes for metadata writes.  For
guest-initiated writes, a writethrough cache is faked in the block layer.
So we can always open in writeback mode.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
master
Paolo Bonzini 2012-06-06 00:04:53 +02:00 committed by Kevin Wolf
parent 425b01487a
commit e1e9b0aca0
1 changed files with 2 additions and 1 deletions

View File

@ -649,12 +649,13 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename,
bs->opaque = g_malloc0(drv->instance_size);
bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB);
open_flags = flags | BDRV_O_CACHE_WB;
/*
* Clear flags that are internal to the block layer before opening the
* image.
*/
open_flags = flags & ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
/*
* Snapshots should be writable.