diff options
Diffstat (limited to 'block/mirror.c')
| -rw-r--r-- | block/mirror.c | 119 |
1 files changed, 91 insertions, 28 deletions
diff --git a/block/mirror.c b/block/mirror.c index e8e8844afc..26acf4af6f 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -42,6 +42,7 @@ typedef struct MirrorBlockJob { BlockBackend *target; BlockDriverState *mirror_top_bs; BlockDriverState *base; + BlockDriverState *base_overlay; /* The name of the graph node to replace */ char *replaces; @@ -677,8 +678,10 @@ static int mirror_exit_common(Job *job) &error_abort); if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { BlockDriverState *backing = s->is_none_mode ? src : s->base; - if (backing_bs(target_bs) != backing) { - bdrv_set_backing_hd(target_bs, backing, &local_err); + BlockDriverState *unfiltered_target = bdrv_skip_filters(target_bs); + + if (bdrv_cow_bs(unfiltered_target) != backing) { + bdrv_set_backing_hd(unfiltered_target, backing, &local_err); if (local_err) { error_report_err(local_err); local_err = NULL; @@ -740,7 +743,7 @@ static int mirror_exit_common(Job *job) * valid. */ block_job_remove_all_bdrv(bjob); - bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); + bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort); /* We just changed the BDS the job BB refers to (with either or both of the * bdrv_replace_node() calls), so switch the BB back so the cleanup does @@ -786,7 +789,6 @@ static void coroutine_fn mirror_throttle(MirrorBlockJob *s) static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) { int64_t offset; - BlockDriverState *base = s->base; BlockDriverState *bs = s->mirror_top_bs->backing->bs; BlockDriverState *target_bs = blk_bs(s->target); int ret; @@ -837,7 +839,8 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) return 0; } - ret = bdrv_is_allocated_above(bs, base, false, offset, bytes, &count); + ret = bdrv_is_allocated_above(bs, s->base_overlay, true, offset, bytes, + &count); if (ret < 0) { return ret; } @@ -936,7 +939,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) } else { s->target_cluster_size = BDRV_SECTOR_SIZE; } - if (backing_filename[0] && !target_bs->backing && + if (backing_filename[0] && !bdrv_backing_chain_next(target_bs) && s->granularity < s->target_cluster_size) { s->buf_size = MAX(s->buf_size, s->target_cluster_size); s->cow_bitmap = bitmap_new(length); @@ -1116,8 +1119,9 @@ static void mirror_complete(Job *job, Error **errp) if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) { int ret; - assert(!target->backing); - ret = bdrv_open_backing_file(target, NULL, "backing", errp); + assert(!bdrv_backing_chain_next(target)); + ret = bdrv_open_backing_file(bdrv_skip_filters(target), NULL, + "backing", errp); if (ret < 0) { return; } @@ -1527,7 +1531,6 @@ static BlockDriver bdrv_mirror_top = { .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes, .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard, .bdrv_co_flush = bdrv_mirror_top_flush, - .bdrv_co_block_status = bdrv_co_block_status_from_backing, .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename, .bdrv_child_perm = bdrv_mirror_top_child_perm, @@ -1555,8 +1558,8 @@ static BlockJob *mirror_start_job( MirrorBlockJob *s; MirrorBDSOpaque *bs_opaque; BlockDriverState *mirror_top_bs; - bool target_graph_mod; bool target_is_backing; + uint64_t target_perms, target_shared_perms; Error *local_err = NULL; int ret; @@ -1575,7 +1578,7 @@ static BlockJob *mirror_start_job( buf_size = DEFAULT_MIRROR_BUF_SIZE; } - if (bs == target) { + if (bdrv_skip_filters(bs) == bdrv_skip_filters(target)) { error_setg(errp, "Can't mirror node into itself"); return NULL; } @@ -1639,15 +1642,50 @@ static BlockJob *mirror_start_job( * In the case of active commit, things look a bit different, though, * because the target is an already populated backing file in active use. * We can allow anything except resize there.*/ + + target_perms = BLK_PERM_WRITE; + target_shared_perms = BLK_PERM_WRITE_UNCHANGED; + target_is_backing = bdrv_chain_contains(bs, target); - target_graph_mod = (backing_mode != MIRROR_LEAVE_BACKING_CHAIN); + if (target_is_backing) { + int64_t bs_size, target_size; + bs_size = bdrv_getlength(bs); + if (bs_size < 0) { + error_setg_errno(errp, -bs_size, + "Could not inquire top image size"); + goto fail; + } + + target_size = bdrv_getlength(target); + if (target_size < 0) { + error_setg_errno(errp, -target_size, + "Could not inquire base image size"); + goto fail; + } + + if (target_size < bs_size) { + target_perms |= BLK_PERM_RESIZE; + } + + target_shared_perms |= BLK_PERM_CONSISTENT_READ + | BLK_PERM_WRITE + | BLK_PERM_GRAPH_MOD; + } else if (bdrv_chain_contains(bs, bdrv_skip_filters(target))) { + /* + * We may want to allow this in the future, but it would + * require taking some extra care. + */ + error_setg(errp, "Cannot mirror to a filter on top of a node in the " + "source's backing chain"); + goto fail; + } + + if (backing_mode != MIRROR_LEAVE_BACKING_CHAIN) { + target_perms |= BLK_PERM_GRAPH_MOD; + } + s->target = blk_new(s->common.job.aio_context, - BLK_PERM_WRITE | BLK_PERM_RESIZE | - (target_graph_mod ? BLK_PERM_GRAPH_MOD : 0), - BLK_PERM_WRITE_UNCHANGED | - (target_is_backing ? BLK_PERM_CONSISTENT_READ | - BLK_PERM_WRITE | - BLK_PERM_GRAPH_MOD : 0)); + target_perms, target_shared_perms); ret = blk_insert_bs(s->target, target, errp); if (ret < 0) { goto fail; @@ -1672,6 +1710,7 @@ static BlockJob *mirror_start_job( s->zero_target = zero_target; s->copy_mode = copy_mode; s->base = base; + s->base_overlay = bdrv_find_overlay(bs, base); s->granularity = granularity; s->buf_size = ROUND_UP(buf_size, granularity); s->unmap = unmap; @@ -1702,15 +1741,39 @@ static BlockJob *mirror_start_job( /* In commit_active_start() all intermediate nodes disappear, so * any jobs in them must be blocked */ if (target_is_backing) { - BlockDriverState *iter; - for (iter = backing_bs(bs); iter != target; 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 (== target). */ + BlockDriverState *iter, *filtered_target; + uint64_t iter_shared_perms; + + /* + * The topmost node with + * bdrv_skip_filters(filtered_target) == bdrv_skip_filters(target) + */ + filtered_target = bdrv_cow_bs(bdrv_find_overlay(bs, target)); + + assert(bdrv_skip_filters(filtered_target) == + bdrv_skip_filters(target)); + + /* + * 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 (== target). + */ + iter_shared_perms = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE; + + for (iter = bdrv_filter_or_cow_bs(bs); iter != target; + iter = bdrv_filter_or_cow_bs(iter)) + { + if (iter == filtered_target) { + /* + * From here on, all nodes are filters on the base. + * This allows us to share BLK_PERM_CONSISTENT_READ. + */ + iter_shared_perms |= BLK_PERM_CONSISTENT_READ; + } + ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, - BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, - errp); + iter_shared_perms, errp); if (ret < 0) { goto fail; } @@ -1746,7 +1809,7 @@ fail: bs_opaque->stop = true; bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, &error_abort); - bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); + bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort); bdrv_unref(mirror_top_bs); @@ -1774,7 +1837,7 @@ void mirror_start(const char *job_id, BlockDriverState *bs, return; } is_none_mode = mode == MIRROR_SYNC_MODE_NONE; - base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; + base = mode == MIRROR_SYNC_MODE_TOP ? bdrv_backing_chain_next(bs) : NULL; mirror_start_job(job_id, bs, creation_flags, target, replaces, speed, granularity, buf_size, backing_mode, zero_target, on_source_error, on_target_error, unmap, NULL, NULL, |