[Qemu-devel] [PATCH v4 0/8] Add metadata overlap checks

[Max Reitz]

If a qcow2 image file becomes corrupted, any write may inadvertently
overwrite important metadata structures such as the L1 table. This
series adds functionality for detecting, preventing and (to some extent)
repairing such collisions.

v4:
 - fixed handling of preallocated zero clusters in patch 4
 - moved OFLAG_COPIED checks into a separate function (this affects
   patches 4 and 5); functionality remains unchanged
 - patches 1, 2, 3, 6, 7 and 8 remain unmodified (except for line
   numbers in block/qcow2-refcount.c)

v3:
 - split PATCH 4/5 into four distinct patches (4/8, 5/8, 6/8 and 7/8,
   respectively)
 - directly generate a JSON message when marking the image corrupt
 - other (minor) fixes according to Kevin's comments

v2:
 - Generally implemented Kevin's comments, especially:
    - new QMP event QEVENT_BLOCK_IMAGE_CORRUPTED
    - removed BDRV_O_REPAIR in favor of BDRV_O_CHECK | BDRV_O_RDWR
    - always check full clusters for overlaps
 - removed qcow2_check_allocations in favor of some
   qcow2_check_refcounts extensions that will hopefully include all
   that functionality

Max Reitz (8):
  qcow2: Add corrupt bit
  qcow2: Metadata overlap checks
  qcow2: Employ metadata overlap checks
  qcow2-refcount: Move OFLAG_COPIED checks
  qcow2-refcount: Repair OFLAG_COPIED errors
  qcow2-refcount: Repair shared refcount blocks
  qcow2_check: Mark image consistent
  qemu-iotests: Overlapping cluster allocations

 block/qcow2-cache.c        |  17 ++
 block/qcow2-cluster.c      |  25 ++-
 block/qcow2-refcount.c     | 481 +++++++++++++++++++++++++++++++++++++++++----
 block/qcow2-snapshot.c     |  22 +++
 block/qcow2.c              |  79 +++++++-
 block/qcow2.h              |  47 ++++-
 docs/specs/qcow2.txt       |   7 +-
 include/block/block.h      |   1 +
 include/monitor/monitor.h  |   1 +
 monitor.c                  |   1 +
 tests/qemu-iotests/031.out |  12 +-
 tests/qemu-iotests/036.out |   2 +-
 tests/qemu-iotests/060     | 111 +++++++++++
 tests/qemu-iotests/060.out |  44 +++++
 tests/qemu-iotests/group   |   1 +
 15 files changed, 804 insertions(+), 47 deletions(-)
 create mode 100755 tests/qemu-iotests/060
 create mode 100644 tests/qemu-iotests/060.out

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1.8.3.1