Eric Blake 86a3d5c688 block: Add .bdrv_co_block_status() callback ... We are gradually moving away from sector-based interfaces, towards byte-based. Now that the block layer exposes byte-based allocation, it's time to tackle the drivers. Add a new callback that operates on as small as byte boundaries. Subsequent patches will then update individual drivers, then finally remove .bdrv_co_get_block_status(). The new code also passes through the 'want_zero' hint, which will allow subsequent patches to further optimize callers that only care about how much of the image is allocated (want_zero is false), rather than full details about runs of zeroes and which offsets the allocation actually maps to (want_zero is true). As part of this effort, fix another part of the documentation: the claim in commit 4c41cb4 that BDRV_BLOCK_ALLOCATED is short for 'DATA || ZERO' is a lie at the block layer (see commit e88ae2264), even though it is how the bit is computed from the driver layer. After all, there are intentionally cases where we return ZERO but not ALLOCATED at the block layer, when we know that a read sees zero because the backing file is too short. Note that the driver interface is thus slightly different than the public interface with regards to which bits will be set, and what guarantees are provided on input. We also add an assertion that any driver using the new callback will make progress (the only time pnum will be 0 is if the block layer already handled an out-of-bounds request, or if there is an error); the old driver interface did not provide this guarantee, which could lead to some inf-loops in drastic corner-case failures. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>		2018-03-02 18:39:07 +01:00
..
accounting.h	block: make accounting thread-safe	2017-06-16 07:55:00 +08:00
aio.h	aio: add missing aio_notify() to aio_enable_external()	2017-05-12 10:36:46 -04:00
block.h	block: Add .bdrv_co_block_status() callback	2018-03-02 18:39:07 +01:00
block_backup.h	backup: Switch block_backup.h to byte-based	2017-07-10 13:18:06 +02:00
block_int.h	block: Add .bdrv_co_block_status() callback	2018-03-02 18:39:07 +01:00
blockjob.h	blockjob: reimplement block_job_sleep_ns to allow cancellation	2017-11-29 15:26:21 +01:00
blockjob_int.h	blockjob: reimplement block_job_sleep_ns to allow cancellation	2017-11-29 15:26:21 +01:00
dirty-bitmap.h	block: maintain persistent disabled bitmaps	2018-02-13 16:59:58 +01:00
nbd.h	nbd: BLOCK_STATUS constants	2018-03-01 14:05:24 -06:00
nvme.h	block: Move NVMe constants to a separate header	2018-02-08 09:22:03 +08:00
qapi.h	Drop superfluous includes of qapi-types.h and test-qapi-types.h	2018-02-09 05:05:11 +01:00
raw-aio.h	linux-aio: share one LinuxAioState within an AioContext	2016-07-18 15:09:31 +01:00
snapshot.h	Move include qemu/option.h from qemu-common.h to actual users	2018-02-09 13:52:16 +01:00
thread-pool.h	Clean up decorations and whitespace around header guards	2016-07-12 16:20:46 +02:00
throttle-groups.h	block: add throttle block filter driver	2017-09-06 10:12:02 +02:00
write-threshold.h	Use scripts/clean-includes to drop redundant qemu/typedefs.h	2016-03-22 22:20:16 +01:00