[Qemu-commits] [qemu/qemu] fe16c7: qcow2: Release read-only bitmaps when inactivated

[Peter Maydell]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: fe16c7ddf82b25e54cb76936a4cdf6bf9327ece5
      
https://github.com/qemu/qemu/commit/fe16c7ddf82b25e54cb76936a4cdf6bf9327ece5
  Author: Max Reitz <mreitz@redhat.com>
  Date:   2020-08-03 (Mon, 03 Aug 2020)

  Changed paths:
    M block/qcow2-bitmap.c

  Log Message:
  -----------
  qcow2: Release read-only bitmaps when inactivated

During migration, we release all bitmaps after storing them on disk, as
long as they are (1) stored on disk, (2) not read-only, and (3)
consistent.

(2) seems arbitrary, though.  The reason we do not release them is
because we do not write them, as there is no need to; and then we just
forget about all bitmaps that we have not written to the file.  However,
read-only persistent bitmaps are still in the file and in sync with
their in-memory representation, so we may as well release them just like
any R/W bitmap that we have updated.

It leads to actual problems, too: After migration, letting the source
continue may result in an error if there were any bitmaps on read-only
nodes (such as backing images), because those have not been released by
bdrv_inactive_all(), but bdrv_invalidate_cache_all() attempts to reload
them (which fails, because they are still present in memory).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200730120234.49288-2-mreitz@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>


  Commit: edadc99a2ee90daeaaf4fba21d623ec8efe7c8e6
      
https://github.com/qemu/qemu/commit/edadc99a2ee90daeaaf4fba21d623ec8efe7c8e6
  Author: Max Reitz <mreitz@redhat.com>
  Date:   2020-08-03 (Mon, 03 Aug 2020)

  Changed paths:
    M tests/qemu-iotests/169
    M tests/qemu-iotests/169.out

  Log Message:
  -----------
  iotests/169: Test source cont with backing bmap

Test migrating from a VM with a persistent bitmap in the backing chain,
and then continuing that VM after the migration

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200730120234.49288-3-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>


  Commit: 45a150aa2b3492acf6691c7bdbeb25a8545d8345
      
https://github.com/qemu/qemu/commit/45a150aa2b3492acf6691c7bdbeb25a8545d8345
  Author: Peter Maydell <peter.maydell@linaro.org>
  Date:   2020-08-03 (Mon, 03 Aug 2020)

  Changed paths:
    M block/qcow2-bitmap.c
    M tests/qemu-iotests/169
    M tests/qemu-iotests/169.out

  Log Message:
  -----------
  Merge remote-tracking branch 'remotes/ericb/tags/pull-bitmaps-2020-08-03' 
into staging

bitmaps patches for 2020-08-03

- fix bitmap migration involving read-only bitmap from backing chain

# gpg: Signature made Mon 03 Aug 2020 15:06:51 BST
# gpg:                using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) 
<ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-bitmaps-2020-08-03:
  iotests/169: Test source cont with backing bmap
  qcow2: Release read-only bitmaps when inactivated

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>


Compare: https://github.com/qemu/qemu/compare/6c5dfc9ccb64...45a150aa2b34