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[PATCH 13/24] block: Mark bdrv_set_backing_hd_drained() GRAPH_WRLOCK
From: |
Kevin Wolf |
Subject: |
[PATCH 13/24] block: Mark bdrv_set_backing_hd_drained() GRAPH_WRLOCK |
Date: |
Fri, 27 Oct 2023 17:53:22 +0200 |
Instead of taking the writer lock internally, require callers to already
hold it when calling bdrv_set_backing_hd_drained(). Basically everthing
in the function needs the lock and 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>
---
include/block/block-global-state.h | 7 ++++---
block.c | 4 ++--
block/stream.c | 2 ++
3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/include/block/block-global-state.h
b/include/block/block-global-state.h
index 9a33bd7ef9..a1fd70ec97 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -101,9 +101,10 @@ bdrv_co_open_blockdev_ref(BlockdevRef *ref, Error **errp);
int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
Error **errp);
-int bdrv_set_backing_hd_drained(BlockDriverState *bs,
- BlockDriverState *backing_hd,
- Error **errp);
+int GRAPH_WRLOCK
+bdrv_set_backing_hd_drained(BlockDriverState *bs, BlockDriverState *backing_hd,
+ Error **errp);
+
int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
const char *bdref_key, Error **errp);
diff --git a/block.c b/block.c
index 499b147315..d79a6f41f9 100644
--- a/block.c
+++ b/block.c
@@ -3557,7 +3557,6 @@ int bdrv_set_backing_hd_drained(BlockDriverState *bs,
if (bs->backing) {
assert(bs->backing->bs->quiesce_counter > 0);
}
- bdrv_graph_wrlock(backing_hd);
ret = bdrv_set_backing_noperm(bs, backing_hd, tran, errp);
if (ret < 0) {
@@ -3567,7 +3566,6 @@ int bdrv_set_backing_hd_drained(BlockDriverState *bs,
ret = bdrv_refresh_perms(bs, tran, errp);
out:
tran_finalize(tran, ret);
- bdrv_graph_wrunlock();
return ret;
}
@@ -3580,7 +3578,9 @@ int bdrv_set_backing_hd(BlockDriverState *bs,
BlockDriverState *backing_hd,
bdrv_ref(drain_bs);
bdrv_drained_begin(drain_bs);
+ bdrv_graph_wrlock(backing_hd);
ret = bdrv_set_backing_hd_drained(bs, backing_hd, errp);
+ bdrv_graph_wrunlock();
bdrv_drained_end(drain_bs);
bdrv_unref(drain_bs);
diff --git a/block/stream.c b/block/stream.c
index 3f5d773535..0b92410c00 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -99,7 +99,9 @@ static int stream_prepare(Job *job)
}
}
+ bdrv_graph_wrlock(base);
bdrv_set_backing_hd_drained(unfiltered_bs, base, &local_err);
+ bdrv_graph_wrunlock();
/*
* This call will do I/O, so the graph can change again from here on.
--
2.41.0
- Re: [PATCH 02/24] block: Mark bdrv_has_zero_init() and callers GRAPH_RDLOCK, (continued)
- [PATCH 03/24] block: Mark bdrv_filter_bs() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27
- [PATCH 07/24] block: Mark bdrv_skip_implicit_filters() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27
- [PATCH 05/24] block: Mark block_job_add_bdrv() GRAPH_WRLOCK, Kevin Wolf, 2023/10/27
- [PATCH 06/24] block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27
- [PATCH 13/24] block: Mark bdrv_set_backing_hd_drained() GRAPH_WRLOCK,
Kevin Wolf <=
- [PATCH 08/24] block: Mark bdrv_skip_filters() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27
- [PATCH 12/24] block: Mark bdrv_cow_child() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27
- [PATCH 09/24] block: Mark bdrv_(un)freeze_backing_chain() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27
- [PATCH 17/24] block: Protect bs->backing with graph_lock, Kevin Wolf, 2023/10/27
- [PATCH 11/24] block: Mark bdrv_filter_child() and callers GRAPH_RDLOCK, Kevin Wolf, 2023/10/27