mirror of https://gitee.com/openkylin/qemu.git
ceaca56fee
No .bdrv_has_zero_init() implementation returns 1 if growing the file would add non-zero areas (at least with PREALLOC_MODE_OFF), so using it in lieu of this new function was always safe. But on the other hand, it is possible that growing an image that is not zero-initialized would still add a zero-initialized area, like when using nonpreallocating truncation on a preallocated image. For callers that care only about truncation, not about creation with potential preallocation, this new function is useful. Alternatively, we could have added a PreallocMode parameter to bdrv_has_zero_init(). But the only user would have been qemu-img convert, which does not have a plain PreallocMode value right now -- it would have to parse the creation option to obtain it. Therefore, the simpler solution is to let bdrv_has_zero_init() inquire the preallocation status and add the new bdrv_has_zero_init_truncate() that presupposes PREALLOC_MODE_OFF. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190724171239.8764-4-mreitz@redhat.com Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> |
||
|---|---|---|
| .. | ||
| accounting.h | ||
| aio-wait.h | ||
| aio.h | ||
| block.h | ||
| block_backup.h | ||
| block_int.h | ||
| blockjob.h | ||
| blockjob_int.h | ||
| dirty-bitmap.h | ||
| nbd.h | ||
| nvme.h | ||
| qapi.h | ||
| qdict.h | ||
| raw-aio.h | ||
| snapshot.h | ||
| thread-pool.h | ||
| throttle-groups.h | ||
| write-threshold.h | ||