This is a little simpler than the commit block job because it's synchronous and only commits into the immediate backing file, but otherwise doing more or less the same.
Signed-off-by: Kevin Wolf <kw...@redhat.com> --- block/commit.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/block/commit.c b/block/commit.c index 49ffddb..581d161 100644 --- a/block/commit.c +++ b/block/commit.c @@ -396,11 +396,14 @@ fail: int bdrv_commit(BlockDriverState *bs) { BlockBackend *src, *backing; + BlockDriverState *backing_file_bs = NULL; + BlockDriverState *commit_top_bs = NULL; BlockDriver *drv = bs->drv; int64_t sector, total_sectors, length, backing_length; int n, ro, open_flags; int ret = 0; uint8_t *buf = NULL; + Error *local_err = NULL; if (!drv) return -ENOMEDIUM; @@ -423,17 +426,31 @@ int bdrv_commit(BlockDriverState *bs) } } - /* FIXME Use real permissions */ - src = blk_new(0, BLK_PERM_ALL); - backing = blk_new(0, BLK_PERM_ALL); + src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); + backing = blk_new(BLK_PERM_WRITE, BLK_PERM_ALL); + + ret = blk_insert_bs(src, bs, &local_err); + if (ret < 0) { + error_report_err(local_err); + goto ro_cleanup; + } + + /* Insert commit_top block node above backing, so we can write to it */ + backing_file_bs = backing_bs(bs); - ret = blk_insert_bs(src, bs, NULL); + ret = bdrv_new_open_driver(&bdrv_commit_top, &commit_top_bs, NULL, + BDRV_O_RDWR, &local_err); if (ret < 0) { + error_report_err(local_err); goto ro_cleanup; } - ret = blk_insert_bs(backing, bs->backing->bs, NULL); + bdrv_set_backing_hd(commit_top_bs, backing_file_bs); + bdrv_set_backing_hd(bs, commit_top_bs); + + ret = blk_insert_bs(backing, backing_file_bs, &local_err); if (ret < 0) { + error_report_err(local_err); goto ro_cleanup; } @@ -507,6 +524,10 @@ int bdrv_commit(BlockDriverState *bs) ro_cleanup: qemu_vfree(buf); + if (backing_file_bs) { + bdrv_set_backing_hd(bs, backing_file_bs); + } + bdrv_unref(commit_top_bs); blk_unref(src); blk_unref(backing); -- 1.8.3.1