Re: [PATCH v5 0/9] qcow2-bitmaps: rewrite reopening logic

[John Snow <jsnow@redhat.com>]

On 9/27/19 8:23 AM, Vladimir Sementsov-Ogievskiy wrote:
> Hi all!
> 
> Bitmaps reopening is buggy, reopening-rw just not working at all and
> reopening-ro may lead to producing broken incremental
> backup if we do temporary snapshot in a meantime.
> 
> v5:
> 01: - add Max's r-b
>     - fix s/QSIMPLE_INIT/QTAILQ_INIT/ in a comment
> 02: - add Max's and John's a-b
> 03: - improve test to check bitmap hashes in more safe way
> 07: - drop wrong statement from commit message
>     - log events by hand
> 08: - drop 'the' from comment
>     - add Corruption in case of existent IN_USE on RO->RW reopen
> 09: - add Max's a-b and John's r-b
> 
> v4: Drop complicated solution around reopening logic [Kevin], fix
>     the existing bug in a simplest way
> 
> Vladimir Sementsov-Ogievskiy (9):
>   block: switch reopen queue from QSIMPLEQ to QTAILQ
>   block: reverse order for reopen commits
>   iotests: add test-case to 165 to test reopening qcow2 bitmaps to RW
>   block/qcow2-bitmap: get rid of bdrv_has_changed_persistent_bitmaps
>   block/qcow2-bitmap: drop qcow2_reopen_bitmaps_rw_hint()
>   block/qcow2-bitmap: do not remove bitmaps on reopen-ro
>   iotests: add test 260 to check bitmap life after snapshot + commit
>   block/qcow2-bitmap: fix and improve qcow2_reopen_bitmaps_rw
>   qcow2-bitmap: move bitmap reopen-rw code to qcow2_reopen_commit
> 
>  block/qcow2.h                |   5 +-
>  include/block/block.h        |   2 +-
>  include/block/block_int.h    |   6 --
>  include/block/dirty-bitmap.h |   1 -
>  block.c                      |  53 +++++------
>  block/dirty-bitmap.c         |  12 ---
>  block/qcow2-bitmap.c         | 164 ++++++++++++++++++++++-------------
>  block/qcow2.c                |  17 +++-
>  tests/qemu-iotests/165       |  57 +++++++++++-
>  tests/qemu-iotests/165.out   |   4 +-
>  tests/qemu-iotests/260       |  89 +++++++++++++++++++
>  tests/qemu-iotests/260.out   |  52 +++++++++++
>  tests/qemu-iotests/group     |   1 +
>  13 files changed, 343 insertions(+), 120 deletions(-)
>  create mode 100755 tests/qemu-iotests/260
>  create mode 100644 tests/qemu-iotests/260.out
> 

Provisionally staged, pending feedback from Kevin.

Some minor rebase conflicts against the current bitmaps branch:

012/17:[----] [-C] 'block/qcow2-bitmap: get rid of
bdrv_has_changed_persistent_bitmaps'
014/17:[0004] [FC] 'block/qcow2-bitmap: do not remove bitmaps on reopen-ro'
017/17:[----] [-C] 'qcow2-bitmap: move bitmap reopen-rw code to
qcow2_reopen_commit'


12: just context against changed _first and _next prototypes.
14: the signature of bdrv_release_dirty_bitmap has changed, which incurs
a change in the refactor.
17: bdrv_can_store... has changed to bdrv_co_can_store...
    Same for bdrv_remove_persistent.


Thanks, applied to my bitmaps tree:

https://github.com/jnsnow/qemu/commits/bitmaps
https://github.com/jnsnow/qemu.git

--js