From c86422c5549c0983b4b4525b8f56a1c69dd67aa1 Mon Sep 17 00:00:00 2001 From: Emanuele Giuseppe Esposito Date: Fri, 13 Jan 2023 21:42:04 +0100 Subject: block: Convert bdrv_refresh_total_sectors() to co_wrapper_mixed BlockDriver->bdrv_getlength is categorized as IO callback, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since the callback traverses the block nodes graph, which however is only possible in a coroutine. Therefore turn it into a co_wrapper to move the actual function into a coroutine where the lock can be taken. Because now this function creates a new coroutine and polls, we need to take the AioContext lock where it is missing, for the only reason that internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the AioContext lock. This is especially messy when a co_wrapper creates a coroutine and polls in bdrv_open_driver, because this function has so many callers in so many context that it can easily lead to deadlocks. Therefore the new rule for bdrv_open_driver is that the caller must always hold the AioContext lock of the given bs (except if it is a coroutine), because the function calls bdrv_refresh_total_sectors() which is now a co_wrapper. Once the rwlock is ultimated and placed in every place it needs to be, we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext lock. Signed-off-by: Emanuele Giuseppe Esposito Signed-off-by: Kevin Wolf Message-Id: <20230113204212.359076-7-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito Signed-off-by: Kevin Wolf --- tests/unit/test-block-iothread.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'tests/unit') diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c index ff5147f..6dfac64 100644 --- a/tests/unit/test-block-iothread.c +++ b/tests/unit/test-block-iothread.c @@ -832,7 +832,10 @@ static void test_attach_second_node(void) qdict_put_str(options, "driver", "raw"); qdict_put_str(options, "file", "base"); + aio_context_acquire(ctx); filter = bdrv_open(NULL, NULL, options, BDRV_O_RDWR, &error_abort); + aio_context_release(ctx); + g_assert(blk_get_aio_context(blk) == ctx); g_assert(bdrv_get_aio_context(bs) == ctx); g_assert(bdrv_get_aio_context(filter) == ctx); -- cgit v1.1