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 663c6740491..f68cbbe61e5 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 From 690587d109ffe19d6743e4cc80c18b0906b7f9ff Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 13 Oct 2009 13:29:19 -0400 Subject: Btrfs: streamline tree-log btree block writeout Syncing the tree log is a 3 phase operation. 1) write and wait for all the tree log blocks for a given root. 2) write and wait for all the tree log blocks for the tree of tree log roots. 3) write and wait for the super blocks (barriers here) This isn't as efficient as it could be because there is no requirement to wait for the blocks from step one to hit the disk before we start writing the blocks from step two. This commit changes the sequence so that we don't start waiting until all the tree blocks from both steps one and two have been sent to disk. We do this by breaking up btrfs_write_wait_marked_extents into two functions, which is trivial because it was already broken up into two parts. Signed-off-by: Chris Mason --- fs/btrfs/transaction.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/btrfs/transaction.h') diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index f68cbbe61e5..d4e3e7a6938 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -108,5 +108,9 @@ int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, struct btrfs_root *root); int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, struct extent_io_tree *dirty_pages); +int btrfs_write_marked_extents(struct btrfs_root *root, + struct extent_io_tree *dirty_pages); +int btrfs_wait_marked_extents(struct btrfs_root *root, + struct extent_io_tree *dirty_pages); int btrfs_transaction_in_commit(struct btrfs_fs_info *info); #endif -- cgit v1.2.3