static void coroutine_fn commit_run(void *opaque) { CommitBlockJob *s = opaque; BlockDriverState *active = s->active; BlockDriverState *top = s->top; BlockDriverState *base = s->base; BlockDriverState *overlay_bs; int64_t sector_num, end; int ret = 0; int n = 0; void *buf; int bytes_written = 0; int64_t base_len; ret = s->common.len = bdrv_getlength(top); if (s->common.len < 0) { goto exit_restore_reopen; } ret = base_len = bdrv_getlength(base); if (base_len < 0) { goto exit_restore_reopen; } if (base_len < s->common.len) { ret = bdrv_truncate(base, s->common.len); if (ret) { goto exit_restore_reopen; } } end = s->common.len >> BDRV_SECTOR_BITS; buf = qemu_blockalign(top, COMMIT_BUFFER_SIZE); for (sector_num = 0; sector_num < end; sector_num += n) { uint64_t delay_ns = 0; bool copy; wait: /* Note that even when no rate limit is applied we need to yield * with no pending I/O here so that bdrv_drain_all() returns. */ block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); if (block_job_is_cancelled(&s->common)) { break; } /* Copy if allocated above the base */ ret = bdrv_is_allocated_above(top, base, sector_num, COMMIT_BUFFER_SIZE / BDRV_SECTOR_SIZE, &n); copy = (ret == 1); trace_commit_one_iteration(s, sector_num, n, ret); if (copy) { if (s->common.speed) { delay_ns = ratelimit_calculate_delay(&s->limit, n); if (delay_ns > 0) { goto wait; } } ret = commit_populate(top, base, sector_num, n, buf); bytes_written += n * BDRV_SECTOR_SIZE; } if (ret < 0) { if (s->on_error == BLOCKDEV_ON_ERROR_STOP || s->on_error == BLOCKDEV_ON_ERROR_REPORT|| (s->on_error == BLOCKDEV_ON_ERROR_ENOSPC && ret == -ENOSPC)) { goto exit_free_buf; } else { n = 0; continue; } } /* Publish progress */ s->common.offset += n * BDRV_SECTOR_SIZE; } ret = 0; if (!block_job_is_cancelled(&s->common) && sector_num == end) { /* success */ ret = bdrv_drop_intermediate(active, top, base, s->backing_file_str); } exit_free_buf: qemu_vfree(buf); exit_restore_reopen: /* restore base open flags here if appropriate (e.g., change the base back * to r/o). These reopens do not need to be atomic, since we won't abort * even on failure here */ if (s->base_flags != bdrv_get_flags(base)) { bdrv_reopen(base, s->base_flags, NULL); } overlay_bs = bdrv_find_overlay(active, top); if (overlay_bs && s->orig_overlay_flags != bdrv_get_flags(overlay_bs)) { bdrv_reopen(overlay_bs, s->orig_overlay_flags, NULL); } g_free(s->backing_file_str); block_job_completed(&s->common, ret); }