motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-04 16:23:55 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

block: Mark bdrv_replace_node() GRAPH_WRLOCK

Browse source 
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
Download patch file Download diff file Expand all files Collapse all files

26
block/mirror.c
View file

@ -712,6 +712,7 @@ static int mirror_exit_common(Job *job)
* these permissions any more means that we can't allow any new requests on
* mirror_top_bs from now on, so keep it drained. */
bdrv_drained_begin(mirror_top_bs);
bdrv_drained_begin(target_bs);
bs_opaque->stop = true;
bdrv_graph_rdlock_main_loop();
@ -757,15 +758,13 @@ static int mirror_exit_common(Job *job)
/* The mirror job has no requests in flight any more, but we need to
* drain potential other users of the BDS before changing the graph. */
assert(s->in_drain);
bdrv_drained_begin(target_bs);
bdrv_drained_begin(to_replace);
/*
* Cannot use check_to_replace_node() here, because that would
* check for an op blocker on @to_replace, and we have our own
* there.
*
* TODO Pull out the writer lock from bdrv_replace_node() to here
*/
bdrv_graph_rdlock_main_loop();
bdrv_graph_wrlock(target_bs);
if (bdrv_recurse_can_replace(src, to_replace)) {
bdrv_replace_node(to_replace, target_bs, &local_err);
} else {
@ -774,8 +773,8 @@ static int mirror_exit_common(Job *job)
"would not lead to an abrupt change of visible data",
to_replace->node_name, target_bs->node_name);
}
bdrv_graph_rdunlock_main_loop();
bdrv_drained_end(target_bs);
bdrv_graph_wrunlock();
bdrv_drained_end(to_replace);
if (local_err) {
error_report_err(local_err);
ret = -EPERM;
@ -790,7 +789,6 @@ static int mirror_exit_common(Job *job)
aio_context_release(replace_aio_context);
}
g_free(s->replaces);
bdrv_unref(target_bs);
/*
* Remove the mirror filter driver from the graph. Before this, get rid of
@ -798,7 +796,12 @@ static int mirror_exit_common(Job *job)
* valid.
*/
block_job_remove_all_bdrv(bjob);
bdrv_graph_wrlock(mirror_top_bs);
bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
bdrv_graph_wrunlock();
bdrv_drained_end(target_bs);
bdrv_unref(target_bs);
bs_opaque->job = NULL;
@ -1987,11 +1990,14 @@ fail:
}
bs_opaque->stop = true;
bdrv_graph_rdlock_main_loop();
bdrv_drained_begin(bs);
bdrv_graph_wrlock(bs);
assert(mirror_top_bs->backing->bs == bs);
bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
&error_abort);
bdrv_graph_rdunlock_main_loop();
bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
bdrv_replace_node(mirror_top_bs, bs, &error_abort);
bdrv_graph_wrunlock();
bdrv_drained_end(bs);
bdrv_unref(mirror_top_bs);