From 9c93c238c15ffd8d5622c51a475d5fb35f65ca07 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 26 Jul 2023 16:57:13 +0100 Subject: [PATCH] btrfs: avoid start and commit empty transaction when flushing qgroups When flushing qgroups, we try to join a running transaction, with btrfs_join_transaction(), and then commit the transaction. However using btrfs_join_transaction() will result in creating a new transaction in case there isn't any running or if there's an existing one already committing. This is pointless as we only need to attach to an existing one that is not committing and in case there's an existing one committing, wait for its commit to complete. Creating and committing an empty transaction is wasteful, pointless IO and unnecessary rotation of the backup roots. So use btrfs_attach_transaction_barrier() instead, to avoid creating and committing empty transactions. Signed-off-by: Filipe Manana Signed-off-by: David Sterba --- fs/btrfs/qgroup.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 1ef60ea8f0bc4..b99230db3c820 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -3758,9 +3758,11 @@ static int try_flush_qgroup(struct btrfs_root *root) goto out; btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1); - trans = btrfs_join_transaction(root); + trans = btrfs_attach_transaction_barrier(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); + if (ret == -ENOENT) + ret = 0; goto out; } -- 2.30.2