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authorChris Mason <chris.mason@oracle.com>2009-10-13 13:21:08 -0400
committerChris Mason <chris.mason@oracle.com>2009-10-13 13:35:12 -0400
commit257c62e1bce03e5b9f3f069fd52ad73a56de71fd (patch)
treead047fe5796156aa88e3f3600111bf2b8d12759f /fs/btrfs/disk-io.c
parent4722607db6a78bd7748c51fa4c8d7371da797254 (diff)
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 <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r--fs/btrfs/disk-io.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ac8927bdc33..d4132aad9ea 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -919,6 +919,7 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
atomic_set(&root->log_writers, 0);
root->log_batch = 0;
root->log_transid = 0;
+ root->last_log_commit = 0;
extent_io_tree_init(&root->dirty_log_pages,
fs_info->btree_inode->i_mapping, GFP_NOFS);
@@ -1089,6 +1090,7 @@ int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
WARN_ON(root->log_root);
root->log_root = log_root;
root->log_transid = 0;
+ root->last_log_commit = 0;
return 0;
}