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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/inode.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/inode.c')
-rw-r--r--fs/btrfs/inode.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ef399a7794f..5b9567caba0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3480,6 +3480,7 @@ static noinline void init_btrfs_i(struct inode *inode)
bi->generation = 0;
bi->sequence = 0;
bi->last_trans = 0;
+ bi->last_sub_trans = 0;
bi->logged_trans = 0;
bi->delalloc_bytes = 0;
bi->reserved_bytes = 0;
@@ -4980,7 +4981,9 @@ again:
set_page_dirty(page);
SetPageUptodate(page);
- BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
+ BTRFS_I(inode)->last_trans = root->fs_info->generation;
+ BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
+
unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
out_unlock:
@@ -5100,6 +5103,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
if (!ei)
return NULL;
ei->last_trans = 0;
+ ei->last_sub_trans = 0;
ei->logged_trans = 0;
ei->outstanding_extents = 0;
ei->reserved_extents = 0;