This includes some permission limiting (for example, we only need to take the RESIZE permission for active commits where the base is smaller than the top).
Signed-off-by: Max Reitz <mre...@redhat.com> --- block/mirror.c | 110 +++++++++++++++++++++++++++++++++++++------------ blockdev.c | 47 +++++++++++++++++---- 2 files changed, 124 insertions(+), 33 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 4fa8f57c80..3d767e3030 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -660,8 +660,10 @@ 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_rw_filters(target_bs); + + if (bdrv_filtered_cow_bs(unfiltered_target) != backing) { + bdrv_set_backing_hd(unfiltered_target, backing, &local_err); if (local_err) { error_report_err(local_err); ret = -EPERM; @@ -711,7 +713,7 @@ static int mirror_exit_common(Job *job) block_job_remove_all_bdrv(bjob); bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, &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); /* 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 @@ -757,6 +759,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) { int64_t offset; BlockDriverState *base = s->base; + BlockDriverState *filtered_base; BlockDriverState *bs = s->mirror_top_bs->backing->bs; BlockDriverState *target_bs = blk_bs(s->target); int ret; @@ -795,6 +798,9 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) s->initial_zeroing_ongoing = false; } + /* Will be NULL if @base is not in @bs's chain */ + filtered_base = bdrv_filtered_cow_bs(bdrv_find_overlay(bs, base)); + /* First part, loop on the sectors and initialize the dirty bitmap. */ for (offset = 0; offset < s->bdev_length; ) { /* Just to make sure we are not exceeding int limit. */ @@ -807,7 +813,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) return 0; } - ret = bdrv_is_allocated_above(bs, base, offset, bytes, &count); + ret = bdrv_is_allocated_above(bs, filtered_base, offset, bytes, &count); if (ret < 0) { return ret; } @@ -903,7 +909,7 @@ 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); @@ -1083,8 +1089,9 @@ 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_rw_filters(target), NULL, + "backing", errp); if (ret < 0) { return; } @@ -1503,8 +1510,8 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, 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; @@ -1523,7 +1530,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, buf_size = DEFAULT_MIRROR_BUF_SIZE; } - if (bs == target) { + if (bdrv_skip_rw_filters(bs) == bdrv_skip_rw_filters(target)) { error_setg(errp, "Can't mirror node into itself"); return; } @@ -1583,15 +1590,42 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, * 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; + } + + 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; @@ -1641,15 +1675,39 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, /* 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_rw_filters(filtered_target) == bdrv_skip_rw_filters(target) + */ + filtered_target = bdrv_filtered_cow_bs(bdrv_find_overlay(bs, target)); + + assert(bdrv_skip_rw_filters(filtered_target) == + bdrv_skip_rw_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_filtered_bs(bs); iter != target; + iter = bdrv_filtered_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; } @@ -1683,7 +1741,7 @@ fail: bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, &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); } @@ -1706,7 +1764,7 @@ 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, on_source_error, on_target_error, unmap, NULL, NULL, diff --git a/blockdev.c b/blockdev.c index 0f0cf0d9ae..68e8d33447 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3777,7 +3777,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs, return; } - if (!bs->backing && sync == MIRROR_SYNC_MODE_TOP) { + if (!bdrv_backing_chain_next(bs) && sync == MIRROR_SYNC_MODE_TOP) { sync = MIRROR_SYNC_MODE_FULL; } @@ -3826,7 +3826,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs, void qmp_drive_mirror(DriveMirror *arg, Error **errp) { - BlockDriverState *bs; + BlockDriverState *bs, *unfiltered_bs; BlockDriverState *source, *target_bs; AioContext *aio_context; BlockMirrorBackingMode backing_mode; @@ -3835,6 +3835,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) int flags; int64_t size; const char *format = arg->format; + const char *replaces_node_name = NULL; int ret; bs = qmp_get_root_bs(arg->device, errp); @@ -3847,6 +3848,16 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) return; } + /* + * If the user has not instructed us otherwise, we should let the + * block job run from @bs (thus taking into account all filters on + * it) but replace @unfiltered_bs when it finishes (thus not + * removing those filters). + * (And if there are any explicit filters, we should assume the + * user knows how to use the @replaces option.) + */ + unfiltered_bs = bdrv_skip_implicit_filters(bs); + aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); @@ -3860,8 +3871,14 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) } flags = bs->open_flags | BDRV_O_RDWR; - source = backing_bs(bs); + source = bdrv_filtered_cow_bs(unfiltered_bs); if (!source && arg->sync == MIRROR_SYNC_MODE_TOP) { + if (bdrv_filtered_bs(unfiltered_bs)) { + /* @unfiltered_bs is an explicit filter */ + error_setg(errp, "Cannot perform sync=top mirror through an " + "explicitly added filter node on the source"); + goto out; + } arg->sync = MIRROR_SYNC_MODE_FULL; } if (arg->sync == MIRROR_SYNC_MODE_NONE) { @@ -3880,6 +3897,9 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) " named node of the graph"); goto out; } + replaces_node_name = arg->replaces; + } else if (unfiltered_bs != bs) { + replaces_node_name = unfiltered_bs->node_name; } if (arg->mode == NEW_IMAGE_MODE_ABSOLUTE_PATHS) { @@ -3899,6 +3919,9 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) bdrv_img_create(arg->target, format, NULL, NULL, NULL, size, flags, false, &local_err); } else { + /* Implicit filters should not appear in the filename */ + BlockDriverState *explicit_backing = bdrv_skip_implicit_filters(source); + switch (arg->mode) { case NEW_IMAGE_MODE_EXISTING: break; @@ -3906,8 +3929,8 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) /* create new image with backing file */ bdrv_refresh_filename(source); bdrv_img_create(arg->target, format, - source->filename, - source->drv->format_name, + explicit_backing->filename, + explicit_backing->drv->format_name, NULL, size, flags, false, &local_err); break; default: @@ -3943,7 +3966,7 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) } blockdev_mirror_common(arg->has_job_id ? arg->job_id : NULL, bs, target_bs, - arg->has_replaces, arg->replaces, arg->sync, + !!replaces_node_name, replaces_node_name, arg->sync, backing_mode, arg->has_speed, arg->speed, arg->has_granularity, arg->granularity, arg->has_buf_size, arg->buf_size, @@ -3979,7 +4002,7 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id, bool has_auto_dismiss, bool auto_dismiss, Error **errp) { - BlockDriverState *bs; + BlockDriverState *bs, *unfiltered_bs; BlockDriverState *target_bs; AioContext *aio_context; BlockMirrorBackingMode backing_mode = MIRROR_LEAVE_BACKING_CHAIN; @@ -3991,6 +4014,16 @@ void qmp_blockdev_mirror(bool has_job_id, const char *job_id, return; } + /* + * Same as in qmp_drive_mirror(): We want to run the job from @bs, + * but we want to replace @unfiltered_bs on completion. + */ + unfiltered_bs = bdrv_skip_implicit_filters(bs); + if (!has_replaces && unfiltered_bs != bs) { + replaces = unfiltered_bs->node_name; + has_replaces = true; + } + target_bs = bdrv_lookup_bs(target, target, errp); if (!target_bs) { return; -- 2.21.0