From e790b4c20a5124239fe93e91fbc87745e5f2cea6 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 18 Nov 2022 18:41:01 +0100 Subject: [PATCH 19/31] block: Fix locking for bdrv_reopen_queue_child() RH-Author: Stefano Garzarella RH-MergeRequest: 135: block: Simplify drain to prevent QEMU from crashing during snapshot RH-Bugzilla: 2155112 RH-Acked-by: Emanuele Giuseppe Esposito RH-Acked-by: Hanna Czenczek RH-Acked-by: Kevin Wolf RH-Commit: [7/16] 46bb54506c4400b9a1bf66b6bd7987ff67260003 (sgarzarella/qemu-kvm-c-9-s) Callers don't agree whether bdrv_reopen_queue_child() should be called with the AioContext lock held or not. Standardise on holding the lock (as done by QMP blockdev-reopen and the replication block driver) and fix bdrv_reopen() to do the same. Signed-off-by: Kevin Wolf Message-Id: <20221118174110.55183-7-kwolf@redhat.com> Reviewed-by: Hanna Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Kevin Wolf (cherry picked from commit 2e117866d7c96cc17e84cd2946fee1bf3292d814) Signed-off-by: Stefano Garzarella --- block.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index 7999fd08c5..46df410b07 100644 --- a/block.c +++ b/block.c @@ -4151,6 +4151,8 @@ static bool bdrv_recurse_has_child(BlockDriverState *bs, * bs_queue, or the existing bs_queue being used. * * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple(). + * + * To be called with bs->aio_context locked. */ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, BlockDriverState *bs, @@ -4309,6 +4311,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, return bs_queue; } +/* To be called with bs->aio_context locked */ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, BlockDriverState *bs, QDict *options, bool keep_old_opts) @@ -4473,11 +4476,11 @@ int bdrv_reopen(BlockDriverState *bs, QDict *opts, bool keep_old_opts, GLOBAL_STATE_CODE(); bdrv_subtree_drained_begin(bs); + queue = bdrv_reopen_queue(NULL, bs, opts, keep_old_opts); + if (ctx != qemu_get_aio_context()) { aio_context_release(ctx); } - - queue = bdrv_reopen_queue(NULL, bs, opts, keep_old_opts); ret = bdrv_reopen_multiple(queue, errp); if (ctx != qemu_get_aio_context()) { -- 2.31.1