Allow qemu-img to show information about bitmaps stored in qcow2 images.
Add a 'bitmap' meta-command with 'dump' sub-command to retrieve a list of
dirty regions in bitmaps stored in a qcow2 image.
RFC:
- I am not 1000% convinced the bm_list caching is perfectly safe,
especially with respect to migration and inactivation. There are
more efficiencies and tweaks I can make, but I think this is the
minimal set.
- I decided not to gate bitmap info in the "info" command behind
extra flags.
- Bitmap data-gathering in "bitmap dump" could be made more
space-efficient by just reporting one segment at a time,
probably.
- `bitmap rm` and `bitmap mk` need extra work, so I am not submitting
them just yet: rm needs more work around the remove persistence API,
and make needs more work around the "can add" API.
- None of these commands will work with "in use" bitmaps; we need
qemu-img check -r bitmaps support for this. I'm not sure what the
right behavior to "fix" in-use bitmaps should be:
- Cleared: This might be dangerous.
- Fully Set: This is safer, but stupid.
- Deleted: This might be the best option.
- Un-set in-use: VERY dangerous; would rather not.
John Snow (12):
qcow2-bitmap: cache bm_list
qcow2/dirty-bitmap: cache loaded bitmaps
block/qcow2-bitmap: avoid adjusting bm->flags for RO bitmaps
qcow2/dirty-bitmaps: load IN_USE bitmaps if disk is RO
qcow2-bitmap: track bitmap type
qapi: add bitmap info
qcow2-bitmap: add basic bitmaps info
qjson: allow caller to ask for arbitrary indent
qapi/block-core: add BitmapMapping and BitmapEntry structs
qemu-img: split off common chunk of map command
qemu-img: add bitmap dump
qemu-img: add bitmap clear
block/qcow2-bitmap.c | 220 +++++++++++++++++--------
block/qcow2.c | 9 +
block/qcow2.h | 3 +
include/qapi/qmp/qjson.h | 1 +
qapi/block-core.json | 92 ++++++++++-
qemu-img-cmds.hx | 6 +
qemu-img.c | 419 +++++++++++++++++++++++++++++++++++++----------
qobject/qjson.c | 21 +--
8 files changed, 612 insertions(+), 159 deletions(-)