[PATCH v5 00/10] preallocate filter

[Vladimir Sementsov-Ogievskiy]

Hi all!

Here is a filter, which does preallocation on write.

In Virtuozzo we have to deal with some custom distributed storage
solution, where allocation is relatively expensive operation. We have to
workaround it in Qemu, so here is a new filter.

v5: rewrite patch 08 as Nir suggested

v4:
01-04: add r-bs
05: add coroutine_fn tag
06: use QEMU_LOCK_GUARD and fix reqs_lock leak
07: grammar
08-10: add r-b

Vladimir Sementsov-Ogievskiy (10):
  block: simplify comment to BDRV_REQ_SERIALISING
  block/io.c: drop assertion on double waiting for request serialisation
  block/io: split out bdrv_find_conflicting_request
  block/io: bdrv_wait_serialising_requests_locked: drop extra bs arg
  block: bdrv_mark_request_serialising: split non-waiting function
  block: introduce BDRV_REQ_NO_WAIT flag
  block: introduce preallocate filter
  iotests.py: add verify_o_direct helper
  iotests.py: add filter_img_check
  iotests: add 298 to test new preallocate filter driver

 docs/system/qemu-block-drivers.rst.inc |  26 +++
 qapi/block-core.json                   |  20 +-
 include/block/block.h                  |  20 +-
 include/block/block_int.h              |   3 +-
 block/file-posix.c                     |   2 +-
 block/io.c                             | 130 ++++++-----
 block/preallocate.c                    | 291 +++++++++++++++++++++++++
 block/Makefile.objs                    |   1 +
 tests/qemu-iotests/298                 |  50 +++++
 tests/qemu-iotests/298.out             |   6 +
 tests/qemu-iotests/group               |   1 +
 tests/qemu-iotests/iotests.py          |  16 ++
 12 files changed, 498 insertions(+), 68 deletions(-)
 create mode 100644 block/preallocate.c
 create mode 100644 tests/qemu-iotests/298
 create mode 100644 tests/qemu-iotests/298.out

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2.21.3