Add btrfs_end_transaction_throttle to force writers to wait for pending commits

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

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 5a1ee0665ae890d6603ee4cb3cc237ae86888635..69ed5f85a38792d87e23a7e62385e6a3602f4a9d 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -130,8 +130,27 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
        return h;
 }
 
-int btrfs_end_transaction(struct btrfs_trans_handle *trans,
-                         struct btrfs_root *root)
+static noinline int wait_for_commit(struct btrfs_root *root,
+                                   struct btrfs_transaction *commit)
+{
+       DEFINE_WAIT(wait);
+       mutex_lock(&root->fs_info->trans_mutex);
+       while(!commit->commit_done) {
+               prepare_to_wait(&commit->commit_wait, &wait,
+                               TASK_UNINTERRUPTIBLE);
+               if (commit->commit_done)
+                       break;
+               mutex_unlock(&root->fs_info->trans_mutex);
+               schedule();
+               mutex_lock(&root->fs_info->trans_mutex);
+       }
+       mutex_unlock(&root->fs_info->trans_mutex);
+       finish_wait(&commit->commit_wait, &wait);
+       return 0;
+}
+
+static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
+                         struct btrfs_root *root, int throttle)
 {
        struct btrfs_transaction *cur_trans;
 
@@ -140,8 +159,18 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans,
        WARN_ON(cur_trans != trans->transaction);
        WARN_ON(cur_trans->num_writers < 1);
        cur_trans->num_writers--;
+
        if (waitqueue_active(&cur_trans->writer_wait))
                wake_up(&cur_trans->writer_wait);
+
+       if (cur_trans->in_commit && throttle) {
+               int ret;
+               mutex_unlock(&root->fs_info->trans_mutex);
+               ret = wait_for_commit(root, cur_trans);
+               BUG_ON(ret);
+               mutex_lock(&root->fs_info->trans_mutex);
+       }
+
        put_transaction(cur_trans);
        mutex_unlock(&root->fs_info->trans_mutex);
        memset(trans, 0, sizeof(*trans));
@@ -149,6 +178,18 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans,
        return 0;
 }
 
+int btrfs_end_transaction(struct btrfs_trans_handle *trans,
+                         struct btrfs_root *root)
+{
+       return __btrfs_end_transaction(trans, root, 0);
+}
+
+int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
+                                  struct btrfs_root *root)
+{
+       return __btrfs_end_transaction(trans, root, 1);
+}
+
 
 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
                                     struct btrfs_root *root)
@@ -240,25 +281,6 @@ int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
        return 0;
 }
 
-static noinline int wait_for_commit(struct btrfs_root *root,
-                                   struct btrfs_transaction *commit)
-{
-       DEFINE_WAIT(wait);
-       mutex_lock(&root->fs_info->trans_mutex);
-       while(!commit->commit_done) {
-               prepare_to_wait(&commit->commit_wait, &wait,
-                               TASK_UNINTERRUPTIBLE);
-               if (commit->commit_done)
-                       break;
-               mutex_unlock(&root->fs_info->trans_mutex);
-               schedule();
-               mutex_lock(&root->fs_info->trans_mutex);
-       }
-       mutex_unlock(&root->fs_info->trans_mutex);
-       finish_wait(&commit->commit_wait, &wait);
-       return 0;
-}
-
 struct dirty_root {
        struct list_head list;
        struct btrfs_root *root;
@@ -680,6 +702,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                             root->fs_info->btree_inode->i_mapping, GFP_NOFS);
 
        trans->transaction->in_commit = 1;
+printk("trans %Lu in commit\n", trans->transid);
        cur_trans = trans->transaction;
        if (cur_trans->list.prev != &root->fs_info->trans_list) {
                prev_trans = list_entry(cur_trans->list.prev,
@@ -760,6 +783,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        kfree(pinned_copy);
 
        cur_trans->commit_done = 1;
+printk("trans %Lu done in commit\n", cur_trans->transid);
        root->fs_info->last_trans_committed = cur_trans->transid;
        wake_up(&cur_trans->commit_wait);
        put_transaction(cur_trans);