Btrfs: reduce stalls during transaction commit

[linux-2.6-omap-h63xx.git] / fs / btrfs / inode.c

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7d4f948bc22a5b5c811b93b385ff36d5b49e8977..13a17477c4f4dacf91d03519a06cb4ccfd5a78ba 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1502,6 +1502,7 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
        struct btrfs_trans_handle *trans;
        struct btrfs_ordered_extent *ordered_extent;
        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+       struct btrfs_path *path;
        int compressed = 0;
        int ret;
 
@@ -1509,6 +1510,23 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
        if (!ret)
                return 0;
 
+       /*
+        * before we join the transaction, try to do some of our IO.
+        * This will limit the amount of IO that we have to do with
+        * the transaction running.  We're unlikely to need to do any
+        * IO if the file extents are new, the disk_i_size checks
+        * covers the most common case.
+        */
+       if (start < BTRFS_I(inode)->disk_i_size) {
+               path = btrfs_alloc_path();
+               if (path) {
+                       ret = btrfs_lookup_file_extent(NULL, root, path,
+                                                      inode->i_ino,
+                                                      start, 0);
+                       btrfs_free_path(path);
+               }
+       }
+
        trans = btrfs_join_transaction(root, 1);
 
        ordered_extent = btrfs_lookup_ordered_extent(inode, start);