13.06.2019 1:09, Max Reitz wrote: > 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>
ohm, unfortunately I'm far from knowing block/mirror mechanics and interfaces :(. still some comments below. > --- > 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 */ Should we assert that not NULL? Hmm, so this is the way to "skip filters reverse from the base", yes? Worth add a comment? > + 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); don't you want skip filters here? actual target node may be in backing chain, but has separate filters above it > - 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 */ hmm, preexisting, it s/jobs/nodes/ > 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; > -- Best regards, Vladimir