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block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCK

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This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_filter_or_cow_bs() need to hold a reader lock for the graph because
it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231027155333.420094-7-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 17:53:15 +02:00
parent f3bbc53dc5
commit 372b69f503
5 changed files with 32 additions and 16 deletions
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33
block.c
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@ -5435,17 +5435,6 @@ static int bdrv_replace_node_common(BlockDriverState *from,
GLOBAL_STATE_CODE();
if (detach_subchain) {
assert(bdrv_chain_contains(from, to));
assert(from != to);
for (to_cow_parent = from;
bdrv_filter_or_cow_bs(to_cow_parent) != to;
to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent))
{
;
}
}
/* Make sure that @from doesn't go away until we have successfully attached
* all of its parents to @to. */
bdrv_ref(from);
@ -5457,6 +5446,17 @@ static int bdrv_replace_node_common(BlockDriverState *from,
bdrv_graph_wrlock(to);
if (detach_subchain) {
assert(bdrv_chain_contains(from, to));
assert(from != to);
for (to_cow_parent = from;
bdrv_filter_or_cow_bs(to_cow_parent) != to;
to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent))
{
;
}
}
/*
* Do the replacement without permission update.
* Replacement may influence the permissions, we should calculate new
@ -5504,10 +5504,14 @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
int bdrv_drop_filter(BlockDriverState *bs, Error **errp)
{
GLOBAL_STATE_CODE();
BlockDriverState *child_bs;
return bdrv_replace_node_common(bs, bdrv_filter_or_cow_bs(bs), true, true,
errp);
GLOBAL_STATE_CODE();
bdrv_graph_rdlock_main_loop();
child_bs = bdrv_filter_or_cow_bs(bs);
bdrv_graph_rdunlock_main_loop();
return bdrv_replace_node_common(bs, child_bs, true, true, errp);
}
/*
@ -6509,6 +6513,7 @@ 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);