diff mbox series

[14/17] btrfs: avoid starting new transaction when flushing delayed items and refs

Message ID 8d7f2507c523dddd0de8be3a5ae24cbc06836201.1690383587.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: some misc stuff around space flushing and enospc handling | expand

Commit Message

Filipe Manana July 26, 2023, 3:57 p.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

When flushing space we join a transaction to flush delayed items and
delayed references, in order to try to release space. However using
btrfs_join_transaction() not only joins an existing transaction as well
as it starts a new transaction if there is none open. If there is no
transaction open, we don't have neither delayed items nor delayed
references, so creating a new transaction is a waste of time, IO and
creates an unnecessary rotation of the backup roots without gaining any
benefits (including releasing space).

So use btrfs_join_transaction_nostart() when attempting to flush delayed
items and references.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/space-info.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index be5ce209b918..2db92a201697 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -725,9 +725,11 @@  static void flush_space(struct btrfs_fs_info *fs_info,
 		else
 			nr = -1;
 
-		trans = btrfs_join_transaction(root);
+		trans = btrfs_join_transaction_nostart(root);
 		if (IS_ERR(trans)) {
 			ret = PTR_ERR(trans);
+			if (ret == -ENOENT)
+				ret = 0;
 			break;
 		}
 		ret = btrfs_run_delayed_items_nr(trans, nr);
@@ -743,9 +745,11 @@  static void flush_space(struct btrfs_fs_info *fs_info,
 		break;
 	case FLUSH_DELAYED_REFS_NR:
 	case FLUSH_DELAYED_REFS:
-		trans = btrfs_join_transaction(root);
+		trans = btrfs_join_transaction_nostart(root);
 		if (IS_ERR(trans)) {
 			ret = PTR_ERR(trans);
+			if (ret == -ENOENT)
+				ret = 0;
 			break;
 		}
 		if (state == FLUSH_DELAYED_REFS_NR)