This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_chain_contains() need to hold a reader lock for the graph because
it calls bdrv_filter_or_cow_bs(), which accesses bs->file/backing.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
include/block/block-global-state.h | 4 ++-
block.c | 1 -
block/block-copy.c | 2 ++
blockdev.c | 48 +++++++++++++++++-------------
4 files changed, 32 insertions(+), 23 deletions(-)
diff --git a/include/block/block-global-state.h
b/include/block/block-global-state.h
index 545708c35a..9a33bd7ef9 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -199,7 +199,9 @@ XDbgBlockGraph * GRAPH_RDLOCK
bdrv_get_xdbg_block_graph(Error **errp);
BlockDriverState *bdrv_lookup_bs(const char *device,
const char *node_name,
Error **errp);
-bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
+bool GRAPH_RDLOCK
+bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
+
BlockDriverState *bdrv_next_node(BlockDriverState *bs);
BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
diff --git a/block.c b/block.c
index dc1980ee42..bb322df7d8 100644
--- a/block.c
+++ b/block.c
@@ -6524,7 +6524,6 @@ bool bdrv_chain_contains(BlockDriverState *top,
BlockDriverState *base)
{
GLOBAL_STATE_CODE();
- GRAPH_RDLOCK_GUARD_MAINLOOP();
while (top && top != base) {
top = bdrv_filter_or_cow_bs(top);
diff --git a/block/block-copy.c b/block/block-copy.c
index 6b2be3d204..9ee3dd7ef5 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -399,7 +399,9 @@ BlockCopyState *block_copy_state_new(BdrvChild *source,
BdrvChild *target,
* For more information see commit f8d59dfb40bb and test
* tests/qemu-iotests/222
*/
+ bdrv_graph_rdlock_main_loop();
is_fleecing = bdrv_chain_contains(target->bs, source->bs);
+ bdrv_graph_rdunlock_main_loop();
s = g_new(BlockCopyState, 1);
*s = (BlockCopyState) {
diff --git a/blockdev.c b/blockdev.c
index 0d9c821e66..368cec3747 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2441,11 +2441,12 @@ void qmp_block_stream(const char *job_id, const char
*device,
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
+ bdrv_graph_rdlock_main_loop();
if (base) {
base_bs = bdrv_find_backing_image(bs, base);
if (base_bs == NULL) {
error_setg(errp, "Can't find '%s' in the backing chain", base);
- goto out;
+ goto out_rdlock;
}
assert(bdrv_get_aio_context(base_bs) == aio_context);
}
@@ -2453,38 +2454,36 @@ void qmp_block_stream(const char *job_id, const char
*device,
if (base_node) {
base_bs = bdrv_lookup_bs(NULL, base_node, errp);
if (!base_bs) {
- goto out;
+ goto out_rdlock;
}
if (bs == base_bs || !bdrv_chain_contains(bs, base_bs)) {
error_setg(errp, "Node '%s' is not a backing image of '%s'",
base_node, device);
- goto out;
+ goto out_rdlock;
}
assert(bdrv_get_aio_context(base_bs) == aio_context);
- bdrv_graph_rdlock_main_loop();
bdrv_refresh_filename(base_bs);
- bdrv_graph_rdunlock_main_loop();
}
if (bottom) {
bottom_bs = bdrv_lookup_bs(NULL, bottom, errp);
if (!bottom_bs) {
- goto out;
+ goto out_rdlock;
}
if (!bottom_bs->drv) {
error_setg(errp, "Node '%s' is not open", bottom);
- goto out;
+ goto out_rdlock;
}
if (bottom_bs->drv->is_filter) {
error_setg(errp, "Node '%s' is a filter, use a non-filter node "
"as 'bottom'", bottom);
- goto out;
+ goto out_rdlock;
}
if (!bdrv_chain_contains(bs, bottom_bs)) {
error_setg(errp, "Node '%s' is not in a chain starting from '%s'",
bottom, device);
- goto out;
+ goto out_rdlock;
}
assert(bdrv_get_aio_context(bottom_bs) == aio_context);
}
@@ -2492,14 +2491,12 @@ void qmp_block_stream(const char *job_id, const char
*device,
/*
* Check for op blockers in the whole chain between bs and base (or bottom)
*/
- bdrv_graph_rdlock_main_loop();
iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs;
for (iter = bs; iter && iter != iter_end;
iter = bdrv_filter_or_cow_bs(iter))
{
if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) {
- bdrv_graph_rdunlock_main_loop();
- goto out;
+ goto out_rdlock;
}
}
bdrv_graph_rdunlock_main_loop();
@@ -2531,6 +2528,11 @@ void qmp_block_stream(const char *job_id, const char
*device,
out:
aio_context_release(aio_context);
+ return;
+
+out_rdlock:
+ bdrv_graph_rdunlock_main_loop();
+ aio_context_release(aio_context);
}
void qmp_block_commit(const char *job_id, const char *device,
@@ -3416,39 +3418,38 @@ void qmp_change_backing_file(const char *device,
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
+ bdrv_graph_rdlock_main_loop();
+
image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
if (local_err) {
error_propagate(errp, local_err);
- goto out;
+ goto out_rdlock;
}
if (!image_bs) {
error_setg(errp, "image file not found");
- goto out;
+ goto out_rdlock;
}
- bdrv_graph_rdlock_main_loop();
if (bdrv_find_base(image_bs) == image_bs) {
error_setg(errp, "not allowing backing file change on an image "
"without a backing file");
- bdrv_graph_rdunlock_main_loop();
- goto out;
+ goto out_rdlock;
}
/* even though we are not necessarily operating on bs, we need it to
* determine if block ops are currently prohibited on the chain */
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) {
- bdrv_graph_rdunlock_main_loop();
- goto out;
+ goto out_rdlock;
}
- bdrv_graph_rdunlock_main_loop();
/* final sanity check */
if (!bdrv_chain_contains(bs, image_bs)) {
error_setg(errp, "'%s' and image file are not in the same chain",
device);
- goto out;
+ goto out_rdlock;
}
+ bdrv_graph_rdunlock_main_loop();
/* if not r/w, reopen to make r/w */
ro = bdrv_is_read_only(image_bs);
@@ -3476,6 +3477,11 @@ void qmp_change_backing_file(const char *device,
out:
aio_context_release(aio_context);
+ return;
+
+out_rdlock:
+ bdrv_graph_rdunlock_main_loop();
+ aio_context_release(aio_context);
}
void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
--
2.41.0
