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qcow2: Unlock the graph in qcow2_do_open() where necessary

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qcow2_do_open() calls a few no_co_wrappers that wrap functions taking
the graph lock internally as a writer. Therefore, it can't hold the
reader lock across these calls, it causes deadlocks. Drop the lock
temporarily around the calls.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230510203601.418015-4-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2023-05-10 22:35:56 +02:00
parent a184563778
commit e3e31dc872
1 changed files with 6 additions and 0 deletions
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6
block/qcow2.c
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@ -1619,9 +1619,11 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
if (open_data_file) {
/* Open external data file */
bdrv_graph_co_rdunlock();
s->data_file = bdrv_co_open_child(NULL, options, "data-file", bs,
&child_of_bds, BDRV_CHILD_DATA,
true, errp);
bdrv_graph_co_rdlock();
if (*errp) {
ret = -EINVAL;
goto fail;
@ -1629,10 +1631,12 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
if (!s->data_file && s->image_data_file) {
bdrv_graph_co_rdunlock();
s->data_file = bdrv_co_open_child(s->image_data_file, options,
"data-file", bs,
&child_of_bds,
BDRV_CHILD_DATA, false, errp);
bdrv_graph_co_rdlock();
if (!s->data_file) {
ret = -EINVAL;
goto fail;
@ -1857,7 +1861,9 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
fail:
g_free(s->image_data_file);
if (open_data_file && has_data_file(bs)) {
bdrv_graph_co_rdunlock();
bdrv_unref_child(bs, s->data_file);
bdrv_graph_co_rdlock();
s->data_file = NULL;
}
g_free(s->unknown_header_fields);