From 5ba6515a2da35bc627dadaceb037533da433d8c7 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Fri, 17 Apr 2015 17:08:37 +0100 Subject: [PATCH] Btrfs: don't attach unnecessary extents to transaction on fsync We don't need to attach ordered extents that have completed to the current transaction. Doing so only makes us hold memory for longer than necessary and delaying the iput of the inode until the transaction is committed (for each created ordered extent we do an igrab and then schedule an asynchronous iput when the ordered extent's reference count drops to 0), preventing the inode from being evictable until the transaction commits. Signed-off-by: Filipe Manana Signed-off-by: Chris Mason --- fs/btrfs/ordered-data.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index ceccd078c93dd..89656d799ff6f 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -502,7 +502,21 @@ void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans, wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)); - list_add_tail(&ordered->trans_list, &trans->ordered); + /* + * If our ordered extent completed it means it updated the + * fs/subvol and csum trees already, so no need to make the + * current transaction's commit wait for it, as we end up + * holding memory unnecessarily and delaying the inode's iput + * until the transaction commit (we schedule an iput for the + * inode when the ordered extent's refcount drops to 0), which + * prevents it from being evictable until the transaction + * commits. + */ + if (test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) + btrfs_put_ordered_extent(ordered); + else + list_add_tail(&ordered->trans_list, &trans->ordered); + spin_lock_irq(&log->log_extents_lock[index]); } spin_unlock_irq(&log->log_extents_lock[index]); -- 2.39.5