This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_cow_child() need to hold a reader lock for the graph because it
accesses bs->backing.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
include/block/block_int-io.h | 5 +++--
block/stream.c | 2 +-
qemu-img.c | 11 ++++++++---
3 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h
index 17547a2dab..4a7cf2b4fd 100644
--- a/include/block/block_int-io.h
+++ b/include/block/block_int-io.h
@@ -130,14 +130,15 @@ bdrv_co_refresh_total_sectors(BlockDriverState *bs, int64_t hint);
int co_wrapper_mixed_bdrv_rdlock
bdrv_refresh_total_sectors(BlockDriverState *bs, int64_t hint);
-BdrvChild *bdrv_cow_child(BlockDriverState *bs);
+BdrvChild * GRAPH_RDLOCK bdrv_cow_child(BlockDriverState *bs);
BdrvChild * GRAPH_RDLOCK bdrv_filter_child(BlockDriverState *bs);
BdrvChild * GRAPH_RDLOCK bdrv_filter_or_cow_child(BlockDriverState *bs);
BdrvChild * GRAPH_RDLOCK bdrv_primary_child(BlockDriverState *bs);
BlockDriverState * GRAPH_RDLOCK bdrv_skip_filters(BlockDriverState *bs);
BlockDriverState * GRAPH_RDLOCK bdrv_backing_chain_next(BlockDriverState *bs);
-static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs)
+static inline BlockDriverState * GRAPH_RDLOCK
+bdrv_cow_bs(BlockDriverState *bs)
{
IO_CODE();
return child_bs(bdrv_cow_child(bs));
diff --git a/block/stream.c b/block/stream.c
index c32c98339a..3f5d773535 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -90,7 +90,7 @@ static int stream_prepare(Job *job)
unfiltered_base = bdrv_skip_filters(base);
bdrv_graph_rdunlock_main_loop();
- if (bdrv_cow_child(unfiltered_bs)) {
+ if (unfiltered_bs_cow) {
const char *base_id = NULL, *base_fmt = NULL;
if (unfiltered_base) {
base_id = s->backing_file_str ?: unfiltered_base->filename;
diff --git a/qemu-img.c b/qemu-img.c
index 33f3ab5fba..5a77f67719 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3541,7 +3541,7 @@ static int img_rebase(int argc, char **argv)
uint8_t *buf_old = NULL;
uint8_t *buf_new = NULL;
BlockDriverState *bs = NULL, *prefix_chain_bs = NULL;
- BlockDriverState *unfiltered_bs;
+ BlockDriverState *unfiltered_bs, *unfiltered_bs_cow;
BlockDriverInfo bdi = {0};
char *filename;
const char *fmt, *cache, *src_cache, *out_basefmt, *out_baseimg;
@@ -3675,6 +3675,7 @@ static int img_rebase(int argc, char **argv)
bdrv_graph_rdlock_main_loop();
unfiltered_bs = bdrv_skip_filters(bs);
+ unfiltered_bs_cow = bdrv_cow_bs(unfiltered_bs);
bdrv_graph_rdunlock_main_loop();
if (compress && !block_driver_can_compress(unfiltered_bs->drv)) {
@@ -3710,7 +3711,11 @@ static int img_rebase(int argc, char **argv)
/* For safe rebasing we need to compare old and new backing file */
if (!unsafe) {
QDict *options = NULL;
- BlockDriverState *base_bs = bdrv_cow_bs(unfiltered_bs);
+ BlockDriverState *base_bs;
+
+ bdrv_graph_rdlock_main_loop();
+ base_bs = bdrv_cow_bs(unfiltered_bs);
+ bdrv_graph_rdunlock_main_loop();
if (base_bs) {
blk_old_backing = blk_new(qemu_get_aio_context(),
@@ -3876,7 +3881,7 @@ static int img_rebase(int argc, char **argv)
* If cluster wasn't changed since prefix_chain, we don't need
* to take action
*/
- ret = bdrv_is_allocated_above(bdrv_cow_bs(unfiltered_bs),
+ ret = bdrv_is_allocated_above(unfiltered_bs_cow,
prefix_chain_bs, false,
offset, n, &n);
if (ret < 0) {
--
2.41.0