fridtjof/qemu-cr16
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

block: introduce BDRV_REQ_MAY_UNMAP request flag

Browse source 
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Peter Lieven 2013-10-24 12:06:52 +02:00 • committed by Kevin Wolf
parent aa7bfbfff7
commit d32f35cbc5
4 changed files with 14 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

7
include/block/block.h
View file

@ -65,6 +65,13 @@ typedef struct BlockDevOps {
typedef enum {
BDRV_REQ_COPY_ON_READ = 0x1,
BDRV_REQ_ZERO_WRITE = 0x2,
/* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
* is allowed to optimize a write zeroes request by unmapping (discarding)
* blocks if it is guaranteed that the result will read back as
* zeroes. The flag is only passed to the driver if the block device is
* opened with BDRV_O_UNMAP.
*/
BDRV_REQ_MAY_UNMAP = 0x4,
} BdrvRequestFlags;
#define BDRV_O_RDWR 0x0002