Btrfs: Only let very young transactions grow during commit

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

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 01c9620bb0016e0cfcc8f1e346e9750060dfe966..9c8f158dd2dbb95dd04a2690efdfa6c946380da3 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -972,6 +972,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        struct extent_io_tree *pinned_copy;
        DEFINE_WAIT(wait);
        int ret;
+       int should_grow = 0;
+       unsigned long now = get_seconds();
 
        /* make a pass through all the delayed refs we have so far
         * any runnings procs may add more while we are here
@@ -1029,6 +1031,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                }
        }
 
+       if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
+               should_grow = 1;
+
        do {
                int snap_pending = 0;
                joined = cur_trans->num_joined;
@@ -1041,7 +1046,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
                if (cur_trans->num_writers > 1)
                        timeout = MAX_SCHEDULE_TIMEOUT;
-               else
+               else if (should_grow)
                        timeout = 1;
 
                mutex_unlock(&root->fs_info->trans_mutex);
@@ -1051,12 +1056,14 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                        BUG_ON(ret);
                }
 
-               schedule_timeout(timeout);
+               smp_mb();
+               if (cur_trans->num_writers > 1 || should_grow)
+                       schedule_timeout(timeout);
 
                mutex_lock(&root->fs_info->trans_mutex);
                finish_wait(&cur_trans->writer_wait, &wait);
        } while (cur_trans->num_writers > 1 ||
-                (cur_trans->num_joined != joined));
+                (should_grow && cur_trans->num_joined != joined));
 
        ret = create_pending_snapshots(trans, root->fs_info);
        BUG_ON(ret);