[PATCH v2 0/4] block: Do not call BlockDriver.bdrv_make_empty() directly

[Max Reitz <mreitz@redhat.com>]

v1: https://lists.nongnu.org/archive/html/qemu-block/2020-04/msg01245.html

Branch: https://github.com/XanClic/qemu.git fix-bdrv_make_empty-v2
Branch: https://git.xanclic.moe/XanClic/qemu.git fix-bdrv_make_empty-v2

Based-on: <20200428192648.749066-1-eblake@redhat.com>
          (“qcow2: Allow resize of images with internal snapshots”)

Hi,

As described in v1’s cover letter (linked above), this series ensures
that all calls to BlockDriver.bdrv_make_empty() go through a wrapper
bdrv_make_empty() function that ensures the caller does have the
necessary permissions.


Changes in v2 (thanks for the quick reviews, I didn’t expect this series
to get attention so quickly :)):
- Added Based-on here in the cover letter [Eric]
- Patch 1: WRITE_UNCHANGED is sufficient [Kevin]
- Patch 3: Check whether blk->root is actually present with
           blk_is_available() [Kevin]
- Patch 4: Let bdrv_commit() only take the WRITE_UNCHANGED permission,
           and take it from the moment the @src BB is created and @bs is
           inserted [Kevin];
           then drop the drv->bdrv_make_empty check, just call
           blk_make_empty() and ignore -ENOTSUP [Eric]


git-backport-diff against v1:

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

001/4:[0002] [FC] 'block: Add bdrv_make_empty()'
002/4:[----] [--] 'block: Use bdrv_make_empty() where possible'
003/4:[0005] [FC] 'block: Add blk_make_empty()'
004/4:[0020] [FC] 'block: Use blk_make_empty() after commits'


Max Reitz (4):
  block: Add bdrv_make_empty()
  block: Use bdrv_make_empty() where possible
  block: Add blk_make_empty()
  block: Use blk_make_empty() after commits

 include/block/block.h          |  1 +
 include/sysemu/block-backend.h |  2 ++
 block.c                        | 23 +++++++++++++++++++++++
 block/block-backend.c          | 10 ++++++++++
 block/commit.c                 | 16 +++++++++-------
 block/replication.c            |  6 ++----
 block/vvfat.c                  |  4 +---
 qemu-img.c                     | 19 ++++++++++++++-----
 8 files changed, 62 insertions(+), 19 deletions(-)

-- 
2.25.4