diff options
| author | Peter Lieven <pl@kamp.de> | 2013-10-24 12:06:52 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2013-11-28 10:30:51 +0100 |
| commit | d32f35cbc5a87af5e1100dd55074a79fc2cb5307 (patch) | |
| tree | 55fa60fcbf692789af57904cb5bc84be7b649df7 /include/block/block.h | |
| parent | aa7bfbfff792538a9eeefe879fc4c629aa0b4203 (diff) | |
| download | qemu-d32f35cbc5a87af5e1100dd55074a79fc2cb5307.zip | |
block: introduce BDRV_REQ_MAY_UNMAP request flag
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'include/block/block.h')
| -rw-r--r-- | include/block/block.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/block/block.h b/include/block/block.h index 8ba9f0c80f..1f30a56fb0 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -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 |