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 | 117 ++++++++++++++++++++++++++++++++++++++-----------
blockdev.c | 47 +++++++++++++++++---
2 files changed, 131 insertions(+), 33 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c
index 54bafdf176..6ddbfb9708 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;
@@ -665,8 +666,10 @@ 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;
@@ -715,7 +718,7 @@ 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
@@ -812,7 +815,8 @@ 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;
}
@@ -908,7 +912,7 @@ 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);
@@ -1088,8 +1092,9 @@ 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;
}
@@ -1531,8 +1536,8 @@ 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;
@@ -1551,7 +1556,7 @@ static BlockJob *mirror_start_job(
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 NULL;
}
@@ -1615,15 +1620,50 @@ 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_rw_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;
@@ -1647,6 +1687,7 @@ static BlockJob *mirror_start_job(
s->backing_mode = backing_mode;
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;
@@ -1693,15 +1734,39 @@ 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_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;
}
@@ -1737,7 +1802,7 @@ 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);
@@ -1764,7 +1829,7 @@ 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 c540802127..c451f553f7 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3851,7 +3851,7 @@ 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;
}
@@ -3900,7 +3900,7 @@ 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;
@@ -3909,6 +3909,7 @@ 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);
@@ -3921,6 +3922,16 @@ 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);
@@ -3934,8 +3945,14 @@ 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) {
@@ -3954,6 +3971,9 @@ 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) {
@@ -3973,6 +3993,9 @@ 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;
@@ -3980,8 +4003,8 @@ 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:
@@ -4017,7 +4040,7 @@ 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,
@@ -4053,7 +4076,7 @@ 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;
@@ -4065,6 +4088,16 @@ 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
