| Message ID | 1460538604-12132-2-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/include/block/block.h b/include/block/block.h index 3a73137..b803597 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -94,6 +94,7 @@ typedef struct HDGeometry { select an appropriate protocol driver, ignoring the format layer */ #define BDRV_O_NO_IO 0x10000 /* don't initialize for I/O */ +#define BDRV_O_NO_LOCK 0x20000 /* don't lock image file */ #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
Later the block layer will automatically lock the images to avoid unexpected concurrent accesses to the same image, which will easily corrupt the metadata or user data, unless in some very special cases, like migration. The exceptional cases like shared storage migration and testing should set BDRV_O_NO_LOCK the flag indicating that the block layer should skip the automatic locking of the image, like the old behavior. Signed-off-by: Fam Zheng <famz@redhat.com> --- include/block/block.h | 1 + 1 file changed, 1 insertion(+)