void stream_start(const char *job_id, BlockDriverState *bs, BlockDriverState *base, const char *backing_file_str, int creation_flags, int64_t speed, BlockdevOnError on_error, Error **errp) { StreamBlockJob *s; BlockDriverState *iter; bool bs_read_only; if (bdrv_freeze_backing_chain(bs, base, errp) < 0) { return; } /* Make sure that the image is opened in read-write mode */ bs_read_only = bdrv_is_read_only(bs); if (bs_read_only) { if (bdrv_reopen_set_read_only(bs, false, errp) != 0) { bs_read_only = false; goto fail; } } /* Prevent concurrent jobs trying to modify the graph structure here, we * already have our own plans. Also don't allow resize as the image size is * queried only at the job start and then cached. */ s = block_job_create(job_id, &stream_job_driver, NULL, bs, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, speed, creation_flags, NULL, NULL, errp); if (!s) { goto fail; } /* Block all intermediate nodes between bs and base, because they will * disappear from the chain after this operation. The streaming job reads * every block only once, assuming that it doesn't change, so block writes * and resizes. */ for (iter = backing_bs(bs); iter && iter != base; iter = backing_bs(iter)) { block_job_add_bdrv(&s->common, "intermediate node", iter, 0, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED, &error_abort); } s->base = base; s->backing_file_str = g_strdup(backing_file_str); s->bs_read_only = bs_read_only; s->chain_frozen = true; s->on_error = on_error; trace_stream_start(bs, base, s); job_start(&s->common.job); return; fail: if (bs_read_only) { bdrv_reopen_set_read_only(bs, true, NULL); } bdrv_unfreeze_backing_chain(bs, base); }
void commit_start(const char *job_id, BlockDriverState *bs, BlockDriverState *base, BlockDriverState *top, int creation_flags, int64_t speed, BlockdevOnError on_error, const char *backing_file_str, const char *filter_node_name, Error **errp) { CommitBlockJob *s; BlockDriverState *iter; BlockDriverState *commit_top_bs = NULL; Error *local_err = NULL; int ret; assert(top != bs); if (top == base) { error_setg(errp, "Invalid files for merge: top and base are the same"); return; } s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL, speed, creation_flags, NULL, NULL, errp); if (!s) { return; } /* convert base to r/w, if necessary */ s->base_read_only = bdrv_is_read_only(base); if (s->base_read_only) { if (bdrv_reopen_set_read_only(base, false, errp) != 0) { goto fail; } } /* Insert commit_top block node above top, so we can block consistent read * on the backing chain below it */ commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0, errp); if (commit_top_bs == NULL) { goto fail; } if (!filter_node_name) { commit_top_bs->implicit = true; } commit_top_bs->total_sectors = top->total_sectors; bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top)); bdrv_set_backing_hd(commit_top_bs, top, &local_err); if (local_err) { bdrv_unref(commit_top_bs); commit_top_bs = NULL; error_propagate(errp, local_err); goto fail; } bdrv_replace_node(top, commit_top_bs, &local_err); if (local_err) { bdrv_unref(commit_top_bs); commit_top_bs = NULL; error_propagate(errp, local_err); goto fail; } s->commit_top_bs = commit_top_bs; bdrv_unref(commit_top_bs); /* Block all nodes between top and base, because they will * disappear from the chain after this operation. */ assert(bdrv_chain_contains(top, base)); for (iter = top; iter != base; iter = backing_bs(iter)) { /* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves * at s->base (if writes are blocked for a node, they are also blocked * for its backing file). The other options would be a second filter * driver above s->base. */ ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, errp); if (ret < 0) { goto fail; } } if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) { goto fail; } s->chain_frozen = true; ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp); if (ret < 0) { goto fail; } s->base = blk_new(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | BLK_PERM_WRITE_UNCHANGED); ret = blk_insert_bs(s->base, base, errp); if (ret < 0) { goto fail; } s->base_bs = base; /* Required permissions are already taken with block_job_add_bdrv() */ s->top = blk_new(0, BLK_PERM_ALL); ret = blk_insert_bs(s->top, top, errp); if (ret < 0) { goto fail; } s->backing_file_str = g_strdup(backing_file_str); s->on_error = on_error; trace_commit_start(bs, base, top, s); job_start(&s->common.job); return; fail: if (s->chain_frozen) { bdrv_unfreeze_backing_chain(commit_top_bs, base); } if (s->base) { blk_unref(s->base); } if (s->top) { blk_unref(s->top); } job_early_fail(&s->common.job); /* commit_top_bs has to be replaced after deleting the block job, * otherwise this would fail because of lack of permissions. */ if (commit_top_bs) { bdrv_replace_node(commit_top_bs, top, &error_abort); } }