The bdrv_is_allocated() interface is not suitable for use while the VM is running. It is a synchronous interface so it may block the running VM for arbitrary amounts of time. It also assumes it is the only block driver operation and there is a risk that internal state could be corrupted if asynchronous I/O is currently pending.
This patch series refactors the block layer so that the bdrv_is_allocated() operation is performed internally in coroutine context. We can then introduce a new public bdrv_co_is_allocated() function that is suitable for use when the VM is running. Making these changes without breaking git bisect means we need to first introduce BlockDriver .bdrv_co_is_allocated() and add wrapper code into bdrv_is_allocated() so existing callers can use converted BlockDrivers. After converting all block drivers there are no .bdrv_is_allocated() functions left and the interface can be removed from BlockDriver. Finally, we can add the new public bdrv_co_is_allocated() public interface and turn the old bdrv_is_allocated() into a wrapper. This series is a prerequisite for copy-on-read, which needs to check whether sectors are allocated while the VM is running. v2: * Rebased on kevin/block and resolved conflicts Stefan Hajnoczi (9): block: use public bdrv_is_allocated() interface block: add .bdrv_co_is_allocated() qed: convert to .bdrv_co_is_allocated() block: convert qcow2, qcow2, and vmdk to .bdrv_co_is_allocated() vvfat: convert to .bdrv_co_is_allocated() vdi: convert to .bdrv_co_is_allocated() cow: convert to .bdrv_co_is_allocated() block: drop .bdrv_is_allocated() interface block: add bdrv_co_is_allocated() interface block.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++----- block.h | 2 + block/cow.c | 8 +++--- block/qcow.c | 8 ++++-- block/qcow2.c | 13 +++++++---- block/qed.c | 15 ++++++++++--- block/vdi.c | 6 ++-- block/vmdk.c | 8 ++++-- block/vvfat.c | 4 +- block_int.h | 4 +- 10 files changed, 94 insertions(+), 32 deletions(-) -- 1.7.7.1
