qemu-img should use QMP commands whenever possible in order to ensure feature completeness of both online and offline image operations. For the "commit" command, this is relatively easy, so implement it first (in the hope that indeed others will follow).
As qemu-img does not have access to QMP (due to QMP being intertwined with basically everything in qemu), we cannot directly use QMP, but at least use the functions the corresponding QMP commands are using (which would be "block-commit", in this case). v2 (mostly following Eric's comments): - Patch 1: - allow giving the granularity as 0 in order to enforce the default value - use is_power_of_2() instead of manually inlining it - use "if (!has_x) { x = DEFAULT_VALUE; }" (which is the common pattern in blockdev.c) instead of "x = has_x ? x : DEFAULT_VALUE;" - Patch 2: - "if (!has_x) { x = DEFAULT_VALUE; }" with a fixed condition - Patch 3: - don't use obsolete error_is_set() - use bs->backing_hd instead of bdrv_find_base(), as the latter actually finds the very base of the backing chain which does not correspond to the current qemu-img commit behavior (which is to commit into the first backing file) - Added patches 5 and 6 Max Reitz (6): block-commit: Expose granularity block-commit: speed is an optional parameter qemu-img: Implement commit like QMP qemu-img: Enable progress output for commit qemu-img: Specify backing file for commit iotests: Commit tests for two-layer backing chains block/Makefile.objs | 2 +- block/commit.c | 16 +- block/mirror.c | 4 +- blockdev.c | 26 +- include/block/block_int.h | 6 +- qapi-schema.json | 6 +- qemu-img-cmds.hx | 4 +- qemu-img.c | 113 ++- qemu-img.texi | 8 +- tests/qemu-iotests/020 | 57 +- tests/qemu-iotests/020.out | 2168 ++++++++++++++++++++++++++++++++++++++++++++ 11 files changed, 2368 insertions(+), 42 deletions(-) -- 1.9.1