From 0f873eca82a0bee45f38862e0ea2ac7b1c2a31bd Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 27 Apr 2016 09:59:38 -0400 Subject: [PATCH] btrfs: fix deadlock in delayed_ref_async_start "Btrfs: track transid for delayed ref flushing" was deadlocking on btrfs_attach_transaction because its not safe to call from the async delayed ref start code. This commit brings back btrfs_join_transaction instead and checks for a blocked commit. Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index ecfa52002363..82b912a293ab 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2851,16 +2851,13 @@ static void delayed_ref_async_start(struct btrfs_work *work) async = container_of(work, struct async_delayed_refs, work); - trans = btrfs_attach_transaction(async->root); - if (IS_ERR(trans)) { - if (PTR_ERR(trans) != -ENOENT) - async->error = PTR_ERR(trans); + /* if the commit is already started, we don't need to wait here */ + if (btrfs_transaction_blocked(async->root->fs_info)) goto done; - } - /* Don't bother flushing if we got into a different transaction */ - if (trans->transid != async->transid) { - btrfs_end_transaction(trans, async->root); + trans = btrfs_join_transaction(async->root); + if (IS_ERR(trans)) { + async->error = PTR_ERR(trans); goto done; } @@ -2869,10 +2866,15 @@ static void delayed_ref_async_start(struct btrfs_work *work) * wait on delayed refs */ trans->sync = true; + + /* Don't bother flushing if we got into a different transaction */ + if (trans->transid > async->transid) + goto end; + ret = btrfs_run_delayed_refs(trans, async->root, async->count); if (ret) async->error = ret; - +end: ret = btrfs_end_transaction(trans, async->root); if (ret && !async->error) async->error = ret; -- 2.20.1