From 257c62e1bce03e5b9f3f069fd52ad73a56de71fd Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 13 Oct 2009 13:21:08 -0400 Subject: Btrfs: avoid tree log commit when there are no changes rpm has a habit of running fdatasync when the file hasn't changed. We already detect if a file hasn't been changed in the current transaction but it might have been sent to the tree-log in this transaction and not changed since the last call to fsync. In this case, we want to avoid a tree log sync, which includes a number of synchronous writes and barriers. This commit extends the existing tracking of the last transaction to change a file to also track the last sub-transaction. The end result is that rpm -ivh and -Uvh are roughly twice as fast, and on par with ext3. Signed-off-by: Chris Mason --- fs/btrfs/transaction.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/btrfs/transaction.h') diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 663c67404918..f68cbbe61e56 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -79,6 +79,7 @@ static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans, struct inode *inode) { BTRFS_I(inode)->last_trans = trans->transaction->transid; + BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid; } int btrfs_end_transaction(struct btrfs_trans_handle *trans, -- cgit v1.2.3