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block: Mark bdrv_replace_node() GRAPH_WRLOCK

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Instead of taking the writer lock internally, require callers to already
hold it when calling bdrv_replace_node(). Its callers may already want
to hold the graph lock and so wouldn't be able to call functions that
take it internally.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231027155333.420094-17-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
2023-10-27 17:53:25 +02:00
parent 5c0ef4954f
commit ccd6a37947
7 changed files with 64 additions and 35 deletions
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30
block.c
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@ -5484,25 +5484,7 @@ out:
int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
Error **errp)
{
int ret;
GLOBAL_STATE_CODE();
/* Make sure that @from doesn't go away until we have successfully attached
* all of its parents to @to. */
bdrv_ref(from);
bdrv_drained_begin(from);
bdrv_drained_begin(to);
bdrv_graph_wrlock(to);
ret = bdrv_replace_node_common(from, to, true, false, errp);
bdrv_graph_wrunlock();
bdrv_drained_end(to);
bdrv_drained_end(from);
bdrv_unref(from);
return ret;
return bdrv_replace_node_common(from, to, true, false, errp);
}
int bdrv_drop_filter(BlockDriverState *bs, Error **errp)
@ -5717,9 +5699,19 @@ BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *options,
goto fail;
}
/*
* Make sure that @bs doesn't go away until we have successfully attached
* all of its parents to @new_node_bs and undrained it again.
*/
bdrv_ref(bs);
bdrv_drained_begin(bs);
bdrv_drained_begin(new_node_bs);
bdrv_graph_wrlock(new_node_bs);
ret = bdrv_replace_node(bs, new_node_bs, errp);
bdrv_graph_wrunlock();
bdrv_drained_end(new_node_bs);
bdrv_drained_end(bs);
bdrv_unref(bs);
if (ret < 0) {
error_prepend(errp, "Could not replace node: ");