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 --- block/commit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'block/commit.c') diff --git a/block/commit.c b/block/commit.c index b346341..41e3599 100644 --- a/block/commit.c +++ b/block/commit.c @@ -123,13 +123,13 @@ static int coroutine_fn commit_run(Job *job, Error **errp) QEMU_AUTO_VFREE void *buf = NULL; int64_t len, base_len; - len = blk_getlength(s->top); + len = blk_co_getlength(s->top); if (len < 0) { return len; } job_progress_set_remaining(&s->common.job, len); - base_len = blk_getlength(s->base); + base_len = blk_co_getlength(s->base); if (base_len < 0) { return base_len; } -- cgit v1.1